chore: make some instance arguments implicit

.github/ISSUE_TEMPLATE/bug_report.md

@@ -39,7 +39,7 @@ Please put an X between the brackets as you perform the following steps:
 
 ### Versions
 
-[Output of `#version` or `#eval Lean.versionString`]
+[Output of `#eval Lean.versionString`]
 [OS version, if not using live.lean-lang.org.]
 
 ### Additional Information

.github/PULL_REQUEST_TEMPLATE.md

@@ -5,10 +5,6 @@
 * Include the link to your `RFC` or `bug` issue in the description.
 * If the issue does not already have approval from a developer, submit the PR as draft.
 * The PR title/description will become the commit message. Keep it up-to-date as the PR evolves.
-* For `feat/fix` PRs, the first paragraph starting with "This PR" must be present and will become a
-  changelog entry unless the PR is labeled with `no-changelog`. If the PR does not have this label,
-  it must instead be categorized with one of the `changelog-*` labels (which will be done by a
-  reviewer for external PRs).
 * A toolchain of the form `leanprover/lean4-pr-releases:pr-release-NNNN` for Linux and M-series Macs will be generated upon build. To generate binaries for Windows and Intel-based Macs as well, write a comment containing `release-ci` on its own line.
 * If you rebase your PR onto `nightly-with-mathlib` then CI will test Mathlib against your PR.
 * You can manage the `awaiting-review`, `awaiting-author`, and `WIP` labels yourself, by writing a comment containing one of these labels on its own line.
@@ -16,6 +12,4 @@
 
 ---
 
-This PR <short changelog summary for feat/fix, see above>.
-
-Closes <`RFC` or `bug` issue number fixed by this PR, if any>
+Closes #0000 (`RFC` or `bug` issue number fixed by this PR, if any)

.github/dependabot.yml

@@ -1,8 +0,0 @@
-version: 2
-updates:
-  - package-ecosystem: "github-actions"
-    directory: "/"
-    schedule:
-      interval: "monthly"
-    commit-message:
-      prefix: "chore: CI"

.github/workflows/actionlint.yml

@@ -17,6 +17,6 @@ jobs:
     - name: Checkout
       uses: actions/checkout@v4
     - name: actionlint
-      uses: raven-actions/actionlint@v2
+      uses: raven-actions/actionlint@v1
       with:
         pyflakes: false # we do not use python scripts

.github/workflows/check-prelude.yml

@@ -11,10 +11,7 @@ jobs:
         with:
           # the default is to use a virtual merge commit between the PR and master: just use the PR
           ref: ${{ github.event.pull_request.head.sha }}
-          sparse-checkout: |
-            src/Lean
-            src/Std
-            src/lake/Lake
+          sparse-checkout: src/Lean
       - name: Check Prelude
         run: |
           failed_files=""
@@ -22,8 +19,8 @@ jobs:
             if ! grep -q "^prelude$" "$file"; then
               failed_files="$failed_files$file\n"
             fi
-          done < <(find src/Lean src/Std src/lake/Lake -name '*.lean' -print0)
+          done < <(find src/Lean -name '*.lean' -print0)
           if [ -n "$failed_files" ]; then
             echo -e "The following files should use 'prelude':\n$failed_files"
             exit 1
-          fi
+          fi

.github/workflows/ci.yml

@@ -217,7 +217,7 @@ jobs:
                 "release": true,
                 "check-level": 2,
                 "shell": "msys2 {0}",
-                "CMAKE_OPTIONS": "-G \"Unix Makefiles\"",
+                "CMAKE_OPTIONS": "-G \"Unix Makefiles\" -DUSE_GMP=OFF",
                 // for reasons unknown, interactivetests are flaky on Windows
                 "CTEST_OPTIONS": "--repeat until-pass:2",
                 "llvm-url": "https://github.com/leanprover/lean-llvm/releases/download/15.0.1/lean-llvm-x86_64-w64-windows-gnu.tar.zst",
@@ -227,7 +227,7 @@ jobs:
               {
                 "name": "Linux aarch64",
                 "os": "nscloud-ubuntu-22.04-arm64-4x8",
-                "CMAKE_OPTIONS": "-DLEAN_INSTALL_SUFFIX=-linux_aarch64",
+                "CMAKE_OPTIONS": "-DUSE_GMP=OFF -DLEAN_INSTALL_SUFFIX=-linux_aarch64",
                 "release": true,
                 "check-level": 2,
                 "shell": "nix develop .#oldGlibcAArch -c bash -euxo pipefail {0}",
@@ -257,7 +257,7 @@ jobs:
                 "cross": true,
                 "shell": "bash -euxo pipefail {0}",
                 // Just a few selected tests because wasm is slow
-                "CTEST_OPTIONS": "-R \"leantest_1007\\.lean|leantest_Format\\.lean|leanruntest\\_1037.lean|leanruntest_ac_rfl\\.lean|leanruntest_tempfile.lean\\.|leanruntest_libuv\\.lean\""
+                "CTEST_OPTIONS": "-R \"leantest_1007\\.lean|leantest_Format\\.lean|leanruntest\\_1037.lean|leanruntest_ac_rfl\\.lean|leanruntest_libuv\\.lean\""
               }
             ];
             console.log(`matrix:\n${JSON.stringify(matrix, null, 2)}`)
@@ -318,7 +318,7 @@ jobs:
         if: github.event_name == 'pull_request'
       # (needs to be after "Checkout" so files don't get overridden)
       - name: Setup emsdk
-        uses: mymindstorm/setup-emsdk@v14
+        uses: mymindstorm/setup-emsdk@v12
         with:
           version: 3.1.44
           actions-cache-folder: emsdk
@@ -452,7 +452,7 @@ jobs:
         run: ccache -s
 
   # This job collects results from all the matrix jobs
-  # This can be made the "required" job, instead of listing each
+  # This can be made the “required” job, instead of listing each
   # matrix job separately
   all-done:
     name: Build matrix complete
@@ -492,7 +492,7 @@ jobs:
         with:
           path: artifacts
       - name: Release
-        uses: softprops/action-gh-release@v2
+        uses: softprops/action-gh-release@v1
         with:
           files: artifacts/*/*
           fail_on_unmatched_files: true
@@ -536,7 +536,7 @@ jobs:
           echo -e "\n*Full commit log*\n" >> diff.md
           git log --oneline "$last_tag"..HEAD | sed 's/^/* /' >> diff.md
       - name: Release Nightly
-        uses: softprops/action-gh-release@v2
+        uses: softprops/action-gh-release@v1
         with:
           body_path: diff.md
           prerelease: true

.github/workflows/labels-from-comments.yml

@@ -1,8 +1,7 @@
 # This workflow allows any user to add one of the `awaiting-review`, `awaiting-author`, `WIP`,
-# `release-ci`, or a `changelog-XXX` label by commenting on the PR or issue.
+# or `release-ci` labels by commenting on the PR or issue.
 # If any labels from the set {`awaiting-review`, `awaiting-author`, `WIP`} are added, other labels
 # from that set are removed automatically at the same time.
-# Similarly, if any `changelog-XXX` label is added, other `changelog-YYY` labels are removed.
 
 name: Label PR based on Comment
 
@@ -12,7 +11,7 @@ on:
 
 jobs:
   update-label:
-    if: github.event.issue.pull_request != null && (contains(github.event.comment.body, 'awaiting-review') || contains(github.event.comment.body, 'awaiting-author') || contains(github.event.comment.body, 'WIP') || contains(github.event.comment.body, 'release-ci') || contains(github.event.comment.body, 'changelog-'))
+    if: github.event.issue.pull_request != null && (contains(github.event.comment.body, 'awaiting-review') || contains(github.event.comment.body, 'awaiting-author') || contains(github.event.comment.body, 'WIP') || contains(github.event.comment.body, 'release-ci'))
     runs-on: ubuntu-latest
 
     steps:
@@ -21,14 +20,13 @@ jobs:
       with:
         github-token: ${{ secrets.GITHUB_TOKEN }}
         script: |
-          const { owner, repo, number: issue_number } = context.issue;
+          const { owner, repo, number: issue_number  } = context.issue;
           const commentLines = context.payload.comment.body.split('\r\n');
 
           const awaitingReview = commentLines.includes('awaiting-review');
           const awaitingAuthor = commentLines.includes('awaiting-author');
           const wip = commentLines.includes('WIP');
           const releaseCI = commentLines.includes('release-ci');
-          const changelogMatch = commentLines.find(line => line.startsWith('changelog-'));
 
           if (awaitingReview || awaitingAuthor || wip) {
             await github.rest.issues.removeLabel({ owner, repo, issue_number, name: 'awaiting-review' }).catch(() => {});
@@ -49,19 +47,3 @@ jobs:
           if (releaseCI) {
             await github.rest.issues.addLabels({ owner, repo, issue_number, labels: ['release-ci'] });
           }
-
-          if (changelogMatch) {
-            const changelogLabel = changelogMatch.trim();
-            const { data: existingLabels } = await github.rest.issues.listLabelsOnIssue({ owner, repo, issue_number });
-            const changelogLabels = existingLabels.filter(label => label.name.startsWith('changelog-'));
-
-            // Remove all other changelog labels
-            for (const label of changelogLabels) {
-              if (label.name !== changelogLabel) {
-                await github.rest.issues.removeLabel({ owner, repo, issue_number, name: label.name }).catch(() => {});
-              }
-            }
-
-            // Add the new changelog label
-            await github.rest.issues.addLabels({ owner, repo, issue_number, labels: [changelogLabel] });
-          }

.github/workflows/nix-ci.yml

@@ -96,7 +96,7 @@ jobs:
           nix build $NIX_BUILD_ARGS .#cacheRoots -o push-build
       - name: Test
         run: |
-          nix build --keep-failed $NIX_BUILD_ARGS .#test -o push-test || (ln -s /tmp/nix-build-*/build/source/src/build ./push-test; false)
+          nix build --keep-failed $NIX_BUILD_ARGS .#test -o push-test || (ln -s /tmp/nix-build-*/source/src/build/ ./push-test; false)
       - name: Test Summary
         uses: test-summary/action@v2
         with:
@@ -110,6 +110,14 @@ jobs:
           # https://github.com/netlify/cli/issues/1809
           cp -r --dereference ./result ./dist
         if: matrix.name == 'Nix Linux'
+      - name: Check manual for broken links
+        id: lychee
+        uses: lycheeverse/lychee-action@v1.9.0
+        with:
+          fail: false  # report errors but do not block CI on temporary failures
+          # gmplib.org consistently times out from GH actions
+          # the GitHub token is to avoid rate limiting
+          args: --base './dist' --no-progress --github-token ${{ secrets.GITHUB_TOKEN }} --exclude 'gmplib.org' './dist/**/*.html'
       - name: Rebuild Nix Store Cache
         run: |
           rm -rf nix-store-cache || true
@@ -121,7 +129,7 @@ jobs:
           python3 -c 'import base64; print("alias="+base64.urlsafe_b64encode(bytes.fromhex("${{github.sha}}")).decode("utf-8").rstrip("="))' >> "$GITHUB_OUTPUT"
           echo "message=`git log -1 --pretty=format:"%s"`" >> "$GITHUB_OUTPUT"
       - name: Publish manual to Netlify
-        uses: nwtgck/actions-netlify@v3.0
+        uses: nwtgck/actions-netlify@v2.0
         id: publish-manual
         with:
           publish-dir: ./dist

.github/workflows/pr-body.yml

@@ -1,25 +0,0 @@
-name: Check PR body for changelog convention
-
-on:
-  merge_group:
-  pull_request:
-    types: [opened, synchronize, reopened, edited, labeled, converted_to_draft, ready_for_review]
-
-jobs:
-  check-pr-body:
-    runs-on: ubuntu-latest
-    steps:
-      - name: Check PR body
-        if: github.event_name == 'pull_request'
-        uses: actions/github-script@v7
-        with:
-          script: |
-            const { title, body, labels, draft } = context.payload.pull_request;
-            if (!draft && /^(feat|fix):/.test(title) && !labels.some(label => label.name == "changelog-no")) {
-              if (!labels.some(label => label.name.startsWith("changelog-"))) {
-                core.setFailed('feat/fix PR must have a `changelog-*` label');
-              }
-              if (!/^This PR [^<]/.test(body)) {
-                core.setFailed('feat/fix PR must have changelog summary starting with "This PR ..." as first line.');
-              }
-            }

.github/workflows/pr-release.yml

@@ -34,7 +34,7 @@ jobs:
       - name: Download artifact from the previous workflow.
         if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' }}
         id: download-artifact
-        uses: dawidd6/action-download-artifact@v7 # https://github.com/marketplace/actions/download-workflow-artifact
+        uses: dawidd6/action-download-artifact@v2 # https://github.com/marketplace/actions/download-workflow-artifact
         with:
           run_id: ${{ github.event.workflow_run.id }}
           path: artifacts
@@ -60,7 +60,7 @@ jobs:
           GH_TOKEN: ${{ secrets.PR_RELEASES_TOKEN }}
       - name: Release
         if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' }}
-        uses: softprops/action-gh-release@v2
+        uses: softprops/action-gh-release@v1
         with:
           name: Release for PR ${{ steps.workflow-info.outputs.pullRequestNumber }}
           # There are coredumps files here as well, but all in deeper subdirectories.
@@ -75,7 +75,7 @@ jobs:
 
       - name: Report release status
         if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' }}
-        uses: actions/github-script@v7
+        uses: actions/github-script@v6
         with:
           script: |
             await github.rest.repos.createCommitStatus({
@@ -111,7 +111,7 @@ jobs:
 
       - name: 'Setup jq'
         if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' }}
-        uses: dcarbone/install-jq-action@v3.0.1
+        uses: dcarbone/install-jq-action@v1.0.1
 
       # Check that the most recently nightly coincides with 'git merge-base HEAD master'
       - name: Check merge-base and nightly-testing-YYYY-MM-DD
@@ -164,10 +164,10 @@ jobs:
 
             # Use GitHub API to check if a comment already exists
             existing_comment="$(curl --retry 3 --location --silent \
-                                    -H "Authorization: token ${{ secrets.MATHLIB4_COMMENT_BOT }}" \
+                                    -H "Authorization: token ${{ secrets.MATHLIB4_BOT }}" \
                                     -H "Accept: application/vnd.github.v3+json" \
                                     "https://api.github.com/repos/leanprover/lean4/issues/${{ steps.workflow-info.outputs.pullRequestNumber }}/comments" \
-                                    | jq 'first(.[] | select(.body | test("^- . Mathlib") or startswith("Mathlib CI status")) | select(.user.login == "leanprover-community-bot"))')"
+                                    | jq 'first(.[] | select(.body | test("^- . Mathlib") or startswith("Mathlib CI status")) | select(.user.login == "leanprover-community-mathlib4-bot"))')"
             existing_comment_id="$(echo "$existing_comment" | jq -r .id)"
             existing_comment_body="$(echo "$existing_comment" | jq -r .body)"
 
@@ -177,14 +177,14 @@ jobs:
               echo "Posting message to the comments: $MESSAGE"
 
               # Append new result to the existing comment or post a new comment
-              # It's essential we use the MATHLIB4_COMMENT_BOT token here, so that Mathlib CI can subsequently edit the comment.
+              # It's essential we use the MATHLIB4_BOT token here, so that Mathlib CI can subsequently edit the comment.
               if [ -z "$existing_comment_id" ]; then
                 INTRO="Mathlib CI status ([docs](https://leanprover-community.github.io/contribute/tags_and_branches.html)):"
                 # Post new comment with a bullet point
                 echo "Posting as new comment at leanprover/lean4/issues/${{ steps.workflow-info.outputs.pullRequestNumber }}/comments"
                 curl -L -s \
                   -X POST \
-                  -H "Authorization: token ${{ secrets.MATHLIB4_COMMENT_BOT }}" \
+                  -H "Authorization: token ${{ secrets.MATHLIB4_BOT }}" \
                   -H "Accept: application/vnd.github.v3+json" \
                   -d "$(jq --null-input --arg intro "$INTRO" --arg val "$MESSAGE" '{"body":($intro + "\n" + $val)}')" \
                   "https://api.github.com/repos/leanprover/lean4/issues/${{ steps.workflow-info.outputs.pullRequestNumber }}/comments"
@@ -193,7 +193,7 @@ jobs:
                 echo "Appending to existing comment at leanprover/lean4/issues/${{ steps.workflow-info.outputs.pullRequestNumber }}/comments"
                 curl -L -s \
                   -X PATCH \
-                  -H "Authorization: token ${{ secrets.MATHLIB4_COMMENT_BOT }}" \
+                  -H "Authorization: token ${{ secrets.MATHLIB4_BOT }}" \
                   -H "Accept: application/vnd.github.v3+json" \
                   -d "$(jq --null-input --arg existing "$existing_comment_body" --arg message "$MESSAGE" '{"body":($existing + "\n" + $message)}')" \
                   "https://api.github.com/repos/leanprover/lean4/issues/comments/$existing_comment_id"
@@ -208,7 +208,7 @@ jobs:
 
       - name: Report mathlib base
         if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' && steps.ready.outputs.mathlib_ready == 'true' }}
-        uses: actions/github-script@v7
+        uses: actions/github-script@v6
         with:
           script: |
             const description =
@@ -340,7 +340,6 @@ jobs:
             # (This should no longer be possible once `nightly-testing-YYYY-MM-DD` is a tag, but it is still safe to merge.)
             git merge "$BASE" --strategy-option ours --no-commit --allow-unrelated-histories
             lake update batteries
-            git add lake-manifest.json
             git commit --allow-empty -m "Trigger CI for https://github.com/leanprover/lean4/pull/${{ steps.workflow-info.outputs.pullRequestNumber }}"
           fi
 

.github/workflows/stale.yml

@@ -11,7 +11,7 @@ jobs:
   stale:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/stale@v9
+      - uses: actions/stale@v8
         with:
           days-before-stale: -1
           days-before-pr-stale: 30

CODEOWNERS

@@ -4,20 +4,22 @@
 # Listed persons will automatically be asked by GitHub to review a PR touching these paths.
 # If multiple names are listed, a review by any of them is considered sufficient by default.
 
-/.github/ @kim-em
-/RELEASES.md @kim-em
+/.github/ @Kha @semorrison
+/RELEASES.md @semorrison
 /src/kernel/ @leodemoura
 /src/lake/ @tydeu
 /src/Lean/Compiler/ @leodemoura
 /src/Lean/Data/Lsp/ @mhuisi
-/src/Lean/Elab/Deriving/ @kim-em
-/src/Lean/Elab/Tactic/ @kim-em
+/src/Lean/Elab/Deriving/ @semorrison
+/src/Lean/Elab/Tactic/ @semorrison
 /src/Lean/Language/ @Kha
 /src/Lean/Meta/Tactic/ @leodemoura
-/src/Lean/PrettyPrinter/ @kmill
+/src/Lean/Parser/ @Kha
+/src/Lean/PrettyPrinter/ @Kha
+/src/Lean/PrettyPrinter/Delaborator/ @kmill
 /src/Lean/Server/ @mhuisi
 /src/Lean/Widget/ @Vtec234
-/src/Init/Data/ @kim-em
+/src/Init/Data/ @semorrison
 /src/Init/Data/Array/Lemmas.lean @digama0
 /src/Init/Data/List/Lemmas.lean @digama0
 /src/Init/Data/List/BasicAux.lean @digama0
@@ -43,4 +45,3 @@
 /src/Std/ @TwoFX
 /src/Std/Tactic/BVDecide/ @hargoniX
 /src/Lean/Elab/Tactic/BVDecide/ @hargoniX
-/src/Std/Sat/ @hargoniX

RELEASES.md

@@ -8,926 +8,9 @@ This file contains work-in-progress notes for the upcoming release, as well as p
 Please check the [releases](https://github.com/leanprover/lean4/releases) page for the current status
 of each version.
 
-v4.16.0
-----------
-
-Development in progress.
-
-v4.15.0
-----------
-
-Release candidate, release notes will be copied from the branch `releases/v4.15.0` once completed.
-
-v4.14.0
-----------
-
-**Full Changelog**: https://github.com/leanprover/lean4/compare/v4.13.0...v4.14.0
-
-### Language features, tactics, and metaprograms
-
-* `structure` and `inductive` commands
-  * [#5517](https://github.com/leanprover/lean4/pull/5517) improves universe level inference for the resulting type of an `inductive` or `structure.` Recall that a `Prop`-valued inductive type is a syntactic subsingleton if it has at most one constructor and all the arguments to the constructor are in `Prop`. Such types have large elimination, so they could be defined in `Type` or `Prop` without any trouble. The way inference has changed is that if a type is a syntactic subsingleton with exactly one constructor, and the constructor has at least one parameter/field, then the `inductive`/`structure` command will prefer creating a `Prop` instead of a `Type`. The upshot is that the `: Prop` in `structure S : Prop` is often no longer needed. (With @arthur-adjedj).
-  * [#5842](https://github.com/leanprover/lean4/pull/5842) and [#5783](https://github.com/leanprover/lean4/pull/5783) implement a feature where the `structure` command can now define recursive inductive types:
-    ```lean
-    structure Tree where
-      n : Nat
-      children : Fin n → Tree
-
-    def Tree.size : Tree → Nat
-      | {n, children} => Id.run do
-        let mut s := 0
-        for h : i in [0 : n] do
-          s := s + (children ⟨i, h.2⟩).size
-        pure s
-    ```
-  * [#5814](https://github.com/leanprover/lean4/pull/5814) fixes a bug where Mathlib's `Type*` elaborator could lead to incorrect universe parameters with the `inductive` command.
-  * [#3152](https://github.com/leanprover/lean4/pull/3152) and [#5844](https://github.com/leanprover/lean4/pull/5844) fix bugs in default value processing for structure instance notation (with @arthur-adjedj).
-  * [#5399](https://github.com/leanprover/lean4/pull/5399) promotes instance synthesis order calculation failure from a soft error to a hard error.
-  * [#5542](https://github.com/leanprover/lean4/pull/5542) deprecates `:=` variants of `inductive` and `structure` (see breaking changes).
-
-* **Application elaboration improvements**
-  * [#5671](https://github.com/leanprover/lean4/pull/5671) makes `@[elab_as_elim]` require at least one discriminant, since otherwise there is no advantage to this alternative elaborator.
-  * [#5528](https://github.com/leanprover/lean4/pull/5528) enables field notation in explicit mode. The syntax `@x.f` elaborates as `@S.f` with `x` supplied to the appropriate parameter.
-  * [#5692](https://github.com/leanprover/lean4/pull/5692) modifies the dot notation resolution algorithm so that it can apply `CoeFun` instances. For example, Mathlib has `Multiset.card : Multiset α →+ Nat`, and now with `m : Multiset α`, the notation `m.card` resolves to `⇑Multiset.card m`.
-  * [#5658](https://github.com/leanprover/lean4/pull/5658) fixes a bug where 'don't know how to synthesize implicit argument' errors might have the incorrect local context when the eta arguments feature is activated.
-  * [#5933](https://github.com/leanprover/lean4/pull/5933) fixes a bug where `..` ellipses in patterns made use of optparams and autoparams.
-  * [#5770](https://github.com/leanprover/lean4/pull/5770) makes dot notation for structures resolve using *all* ancestors. Adds a *resolution order* for generalized field notation. This is the order of namespaces visited during resolution when trying to resolve names. The algorithm to compute a resolution order is the commonly used C3 linearization (used for example by Python), which when successful ensures that immediate parents' namespaces are considered before more distant ancestors' namespaces. By default we use a relaxed version of the algorithm that tolerates inconsistencies, but using `set_option structure.strictResolutionOrder true` makes inconsistent parent orderings into warnings.
-
-* **Recursion and induction principles**
-  * [#5619](https://github.com/leanprover/lean4/pull/5619) fixes functional induction principle generation to avoid over-eta-expanding in the preprocessing step.
-  * [#5766](https://github.com/leanprover/lean4/pull/5766) fixes structural nested recursion so that it is not confused when a nested type appears first.
-  * [#5803](https://github.com/leanprover/lean4/pull/5803) fixes a bug in functional induction principle generation when there are `let` bindings.
-  * [#5904](https://github.com/leanprover/lean4/pull/5904) improves functional induction principle generation to unfold aux definitions more carefully.
-  * [#5850](https://github.com/leanprover/lean4/pull/5850) refactors code for `Predefinition.Structural`.
-
-* **Error messages**
-  * [#5276](https://github.com/leanprover/lean4/pull/5276) fixes a bug in "type mismatch" errors that would structurally assign metavariables during the algorithm to expose differences.
-  * [#5919](https://github.com/leanprover/lean4/pull/5919) makes "type mismatch" errors add type ascriptions to expose differences for numeric literals.
-  * [#5922](https://github.com/leanprover/lean4/pull/5922) makes "type mismatch" errors expose differences in the bodies of functions and pi types.
-  * [#5888](https://github.com/leanprover/lean4/pull/5888) improves the error message for invalid induction alternative names in `match` expressions (@josojo).
-  * [#5719](https://github.com/leanprover/lean4/pull/5719) improves `calc` error messages.
-
-* [#5627](https://github.com/leanprover/lean4/pull/5627) and [#5663](https://github.com/leanprover/lean4/pull/5663) improve the **`#eval` command** and introduce some new features.
-  * Now results can be pretty printed if there is a `ToExpr` instance, which means **hoverable output**. If `ToExpr` fails, it then tries looking for a `Repr` or `ToString` instance like before. Setting `set_option eval.pp false` disables making use of `ToExpr` instances.
-  * There is now **auto-derivation** of `Repr` instances, enabled with the `pp.derive.repr` option (default to **true**). For example:
-    ```lean
-    inductive Baz
-    | a | b
-
-    #eval Baz.a
-    -- Baz.a
-    ```
-    It simply does `deriving instance Repr for Baz` when there's no way to represent `Baz`.
-  * The option `eval.type` controls whether or not to include the type in the output. For now the default is false.
-  * Now expressions such as `#eval do return 2`, where monad is unknown, work. It tries unifying the monad with `CommandElabM`, `TermElabM`, or `IO`.
-  * The classes `Lean.Eval` and `Lean.MetaEval` have been removed. These each used to be responsible for adapting monads and printing results. Now the `MonadEval` class is responsible for adapting monads for evaluation (it is similar to `MonadLift`, but instances are allowed to use default data when initializing state), and representing results is handled through a separate process.
-  * Error messages about failed instance synthesis are now more precise. Once it detects that a `MonadEval` class applies, then the error message will be specific about missing `ToExpr`/`Repr`/`ToString` instances.
-  * Fixes bugs where evaluating `MetaM` and `CoreM` wouldn't collect log messages.
-  * Fixes a bug where `let rec` could not be used in `#eval`.
-
-* `partial` definitions
-  * [#5780](https://github.com/leanprover/lean4/pull/5780) improves the error message when `partial` fails to prove a type is inhabited. Add delta deriving.
-  * [#5821](https://github.com/leanprover/lean4/pull/5821) gives `partial` inhabitation the ability to create local `Inhabited` instances from parameters.
-
-* **New tactic configuration syntax.** The configuration syntax for all core tactics has been given an upgrade. Rather than `simp (config := { contextual := true, maxSteps := 22})`, one can now write `simp +contextual (maxSteps := 22)`. Tactic authors can migrate by switching from `(config)?` to `optConfig` in tactic syntaxes and potentially deleting `mkOptionalNode` in elaborators. [#5883](https://github.com/leanprover/lean4/pull/5883), [#5898](https://github.com/leanprover/lean4/pull/5898),  [#5928](https://github.com/leanprover/lean4/pull/5928), and [#5932](https://github.com/leanprover/lean4/pull/5932). (Tactic authors, see breaking changes.)
-
-* `simp` tactic
-  * [#5632](https://github.com/leanprover/lean4/pull/5632) fixes the simpproc for `Fin` literals to reduce more consistently.
-  * [#5648](https://github.com/leanprover/lean4/pull/5648) fixes a bug in `simpa ... using t` where metavariables in `t` were not properly accounted for, and also improves the type mismatch error.
-  * [#5838](https://github.com/leanprover/lean4/pull/5838) fixes the docstring of `simp!` to actually talk about `simp!`.
-  * [#5870](https://github.com/leanprover/lean4/pull/5870) adds support for `attribute [simp ←]` (note the reverse direction). This adds the reverse of a theorem as a global simp theorem.
-
-* `decide` tactic
-  * [#5665](https://github.com/leanprover/lean4/pull/5665) adds `decide!` tactic for using kernel reduction (warning: this is renamed to `decide +kernel` in a future release).
-
-* `bv_decide` tactic
-  * [#5714](https://github.com/leanprover/lean4/pull/5714) adds inequality regression tests (@alexkeizer).
-  * [#5608](https://github.com/leanprover/lean4/pull/5608) adds `bv_toNat` tag for `toNat_ofInt` (@bollu).
-  * [#5618](https://github.com/leanprover/lean4/pull/5618) adds support for `at` in `ac_nf` and uses it in `bv_normalize` (@tobiasgrosser).
-  * [#5628](https://github.com/leanprover/lean4/pull/5628) adds udiv support.
-  * [#5635](https://github.com/leanprover/lean4/pull/5635) adds auxiliary bitblasters for negation and subtraction.
-  * [#5637](https://github.com/leanprover/lean4/pull/5637) adds more `getLsbD` bitblaster theory.
-  * [#5652](https://github.com/leanprover/lean4/pull/5652) adds umod support.
-  * [#5653](https://github.com/leanprover/lean4/pull/5653) adds performance benchmark for modulo.
-  * [#5655](https://github.com/leanprover/lean4/pull/5655) reduces error on `bv_check` to warning.
-  * [#5670](https://github.com/leanprover/lean4/pull/5670) adds `~~~(-x)` support.
-  * [#5673](https://github.com/leanprover/lean4/pull/5673) disables `ac_nf` by default.
-  * [#5675](https://github.com/leanprover/lean4/pull/5675) fixes context tracking in `bv_decide` counter example.
-  * [#5676](https://github.com/leanprover/lean4/pull/5676) adds an error when the LRAT proof is invalid.
-  * [#5781](https://github.com/leanprover/lean4/pull/5781) introduces uninterpreted symbols everywhere.
-  * [#5823](https://github.com/leanprover/lean4/pull/5823) adds `BitVec.sdiv` support.
-  * [#5852](https://github.com/leanprover/lean4/pull/5852) adds `BitVec.ofBool` support.
-  * [#5855](https://github.com/leanprover/lean4/pull/5855) adds `if` support.
-  * [#5869](https://github.com/leanprover/lean4/pull/5869) adds support for all the SMTLIB BitVec divison/remainder operations.
-  * [#5886](https://github.com/leanprover/lean4/pull/5886) adds embedded constraint substitution.
-  * [#5918](https://github.com/leanprover/lean4/pull/5918) fixes loose mvars bug in `bv_normalize`.
-  * Documentation:
-    * [#5636](https://github.com/leanprover/lean4/pull/5636) adds remarks about multiplication.
-
-* `conv` mode
-  * [#5861](https://github.com/leanprover/lean4/pull/5861) improves the `congr` conv tactic to handle "over-applied" functions.
-  * [#5894](https://github.com/leanprover/lean4/pull/5894) improves the `arg` conv tactic so that it can access more arguments and so that it can handle "over-applied" functions (it generates a specialized congruence lemma for the specific argument in question). Makes `arg 1` and `arg 2` apply to pi types in more situations. Adds negative indexing, for example `arg -2` is equivalent to the `lhs` tactic. Makes the `enter [...]` tactic show intermediate states like `rw`.
-
-* **Other tactics**
-  * [#4846](https://github.com/leanprover/lean4/pull/4846) fixes a bug where `generalize ... at *` would apply to implementation details (@ymherklotz).
-  * [#5730](https://github.com/leanprover/lean4/pull/5730) upstreams the `classical` tactic combinator.
-  * [#5815](https://github.com/leanprover/lean4/pull/5815) improves the error message when trying to unfold a local hypothesis that is not a local definition.
-  * [#5862](https://github.com/leanprover/lean4/pull/5862) and [#5863](https://github.com/leanprover/lean4/pull/5863) change how `apply` and `simp` elaborate, making them not disable error recovery. This improves hovers and completions when the term has elaboration errors.
-
-* `deriving` clauses
-  * [#5899](https://github.com/leanprover/lean4/pull/5899) adds declaration ranges for delta-derived instances.
-  * [#5265](https://github.com/leanprover/lean4/pull/5265) removes unused syntax in `deriving` clauses for providing arguments to deriving handlers (see breaking changes).
-
-* [#5065](https://github.com/leanprover/lean4/pull/5065) upstreams and updates `#where`, a command that reports the current scope information.
-
-* **Linters**
-  * [#5338](https://github.com/leanprover/lean4/pull/5338) makes the unused variables linter ignore variables defined in tactics by default now, avoiding performance bottlenecks.
-  * [#5644](https://github.com/leanprover/lean4/pull/5644) ensures that linters in general do not run on `#guard_msgs` itself.
-
-* **Metaprogramming interface**
-  * [#5720](https://github.com/leanprover/lean4/pull/5720) adds `pushGoal`/`pushGoals` and `popGoal` for manipulating the goal state. These are an alternative to `replaceMainGoal` and `getMainGoal`, and with them you don't need to worry about making sure nothing clears assigned metavariables from the goal list between assigning the main goal and using `replaceMainGoal`. Modifies `closeMainGoalUsing`, which is like a `TacticM` version of `liftMetaTactic`. Now the callback is run in a context where the main goal is removed from the goal list, and the callback is free to modify the goal list. Furthermore, the `checkUnassigned` argument has been replaced with `checkNewUnassigned`, which checks whether the value assigned to the goal has any *new* metavariables, relative to the start of execution of the callback. Modifies `withCollectingNewGoalsFrom` to take the `parentTag` argument explicitly rather than indirectly via `getMainTag`. Modifies `elabTermWithHoles` to optionally take `parentTag?`.
-  * [#5563](https://github.com/leanprover/lean4/pull/5563) fixes `getFunInfo` and `inferType` to use `withAtLeastTransparency` rather than `withTransparency`.
-  * [#5679](https://github.com/leanprover/lean4/pull/5679) fixes `RecursorVal.getInduct` to return the name of major argument’s type. This makes "structure eta" work for nested inductives.
-  * [#5681](https://github.com/leanprover/lean4/pull/5681) removes unused `mkRecursorInfoForKernelRec`.
-  * [#5686](https://github.com/leanprover/lean4/pull/5686) makes discrimination trees index the domains of foralls, for better performance of the simplify and type class search.
-  * [#5760](https://github.com/leanprover/lean4/pull/5760) adds `Lean.Expr.name?` recognizer for `Name` expressions.
-  * [#5800](https://github.com/leanprover/lean4/pull/5800) modifies `liftCommandElabM` to preserve more state, fixing an issue where using it would drop messages.
-  * [#5857](https://github.com/leanprover/lean4/pull/5857) makes it possible to use dot notation in `m!` strings, for example `m!"{.ofConstName n}"`.
-  * [#5841](https://github.com/leanprover/lean4/pull/5841) and [#5853](https://github.com/leanprover/lean4/pull/5853) record the complete list of `structure` parents in the `StructureInfo` environment extension.
-
-* **Other fixes or improvements**
-  * [#5566](https://github.com/leanprover/lean4/pull/5566) fixes a bug introduced in [#4781](https://github.com/leanprover/lean4/pull/4781) where heartbeat exceptions were no longer being handled properly. Now such exceptions are tagged with `runtime.maxHeartbeats` (@eric-wieser).
-  * [#5708](https://github.com/leanprover/lean4/pull/5708) modifies the proof objects produced by the proof-by-reflection tactics `ac_nf0` and `simp_arith` so that the kernel is less prone to reducing expensive atoms.
-  * [#5768](https://github.com/leanprover/lean4/pull/5768) adds a `#version` command that prints Lean's version information.
-  * [#5822](https://github.com/leanprover/lean4/pull/5822) fixes elaborator algorithms to match kernel algorithms for primitive projections (`Expr.proj`).
-  * [#5811](https://github.com/leanprover/lean4/pull/5811) improves the docstring for the `rwa` tactic.
-
-
-### Language server, widgets, and IDE extensions
-
-* [#5224](https://github.com/leanprover/lean4/pull/5224) fixes `WorkspaceClientCapabilities` to make `applyEdit` optional, in accordance with the LSP specification (@pzread).
-* [#5340](https://github.com/leanprover/lean4/pull/5340) fixes a server deadlock when shutting down the language server and a desync between client and language server after a file worker crash.
-* [#5560](https://github.com/leanprover/lean4/pull/5560) makes `initialize` and `builtin_initialize` participate in the call hierarchy and other requests.
-* [#5650](https://github.com/leanprover/lean4/pull/5650) makes references in attributes participate in the call hierarchy and other requests.
-* [#5666](https://github.com/leanprover/lean4/pull/5666) add auto-completion in tactic blocks without having to type the first character of the tactic, and adds tactic completion docs to tactic auto-completion items.
-* [#5677](https://github.com/leanprover/lean4/pull/5677) fixes several cases where goal states were not displayed in certain text cursor positions.
-* [#5707](https://github.com/leanprover/lean4/pull/5707) indicates deprecations in auto-completion items.
-* [#5736](https://github.com/leanprover/lean4/pull/5736), [#5752](https://github.com/leanprover/lean4/pull/5752), [#5763](https://github.com/leanprover/lean4/pull/5763), [#5802](https://github.com/leanprover/lean4/pull/5802), and [#5805](https://github.com/leanprover/lean4/pull/5805) fix various performance issues in the language server.
-* [#5801](https://github.com/leanprover/lean4/pull/5801) distinguishes theorem auto-completions from non-theorem auto-completions.
-
-### Pretty printing
-
-* [#5640](https://github.com/leanprover/lean4/pull/5640) fixes a bug where goal states in messages might print newlines as spaces.
-* [#5643](https://github.com/leanprover/lean4/pull/5643) adds option `pp.mvars.delayed` (default false), which when false causes delayed assignment metavariables to pretty print with what they are assigned to. Now `fun x : Nat => ?a` pretty prints as `fun x : Nat => ?a` rather than `fun x ↦ ?m.7 x`.
-* [#5711](https://github.com/leanprover/lean4/pull/5711) adds options `pp.mvars.anonymous` and `pp.mvars.levels`, which when false respectively cause expression metavariables and level metavariables to pretty print as `?_`.
-* [#5710](https://github.com/leanprover/lean4/pull/5710) adjusts the `⋯` elaboration warning to mention `pp.maxSteps`.
-
-* [#5759](https://github.com/leanprover/lean4/pull/5759) fixes the app unexpander for `sorryAx`.
-* [#5827](https://github.com/leanprover/lean4/pull/5827) improves accuracy of binder names in the signature pretty printer (like in output of `#check`). Also fixes the issue where consecutive hygienic names pretty print without a space separating them, so we now have `(x✝ y✝ : Nat)` rather than `(x✝y✝ : Nat)`.
-* [#5830](https://github.com/leanprover/lean4/pull/5830) makes sure all the core delaborators respond to `pp.explicit` when appropriate.
-* [#5639](https://github.com/leanprover/lean4/pull/5639) makes sure name literals use escaping when pretty printing.
-* [#5854](https://github.com/leanprover/lean4/pull/5854) adds delaborators for `<|>`, `<*>`, `>>`, `<*`, and `*>`.
-
-### Library
-
-* `Array`
-  * [#5687](https://github.com/leanprover/lean4/pull/5687) deprecates `Array.data`.
-  * [#5705](https://github.com/leanprover/lean4/pull/5705) uses a better default value for `Array.swapAt!`.
-  * [#5748](https://github.com/leanprover/lean4/pull/5748) moves `Array.mapIdx` lemmas to a new file.
-  * [#5749](https://github.com/leanprover/lean4/pull/5749) simplifies signature of `Array.mapIdx`.
-  * [#5758](https://github.com/leanprover/lean4/pull/5758) upstreams `Array.reduceOption`.
-  * [#5786](https://github.com/leanprover/lean4/pull/5786) adds simp lemmas for `Array.isEqv` and `BEq`.
-  * [#5796](https://github.com/leanprover/lean4/pull/5796) renames `Array.shrink` to `Array.take`, and relates it to `List.take`.
-  * [#5798](https://github.com/leanprover/lean4/pull/5798) upstreams `List.modify`, adds lemmas, relates to `Array.modify`.
-  * [#5799](https://github.com/leanprover/lean4/pull/5799) relates `Array.forIn` and `List.forIn`.
-  * [#5833](https://github.com/leanprover/lean4/pull/5833) adds `Array.forIn'`, and relates to `List`.
-  * [#5848](https://github.com/leanprover/lean4/pull/5848) fixes deprecations in `Init.Data.Array.Basic` to not recommend the deprecated constant.
-  * [#5895](https://github.com/leanprover/lean4/pull/5895) adds `LawfulBEq (Array α) ↔ LawfulBEq α`.
-  * [#5896](https://github.com/leanprover/lean4/pull/5896) moves `@[simp]` from `back_eq_back?` to `back_push`.
-  * [#5897](https://github.com/leanprover/lean4/pull/5897) renames `Array.back` to `back!`.
-
-* `List`
-  * [#5605](https://github.com/leanprover/lean4/pull/5605) removes `List.redLength`.
-  * [#5696](https://github.com/leanprover/lean4/pull/5696) upstreams `List.mapIdx` and adds lemmas.
-  * [#5697](https://github.com/leanprover/lean4/pull/5697) upstreams `List.foldxM_map`.
-  * [#5701](https://github.com/leanprover/lean4/pull/5701) renames `List.join` to `List.flatten`.
-  * [#5703](https://github.com/leanprover/lean4/pull/5703) upstreams `List.sum`.
-  * [#5706](https://github.com/leanprover/lean4/pull/5706) marks `prefix_append_right_inj` as a simp lemma.
-  * [#5716](https://github.com/leanprover/lean4/pull/5716) fixes `List.drop_drop` addition order.
-  * [#5731](https://github.com/leanprover/lean4/pull/5731) renames `List.bind` and `Array.concatMap` to `flatMap`.
-  * [#5732](https://github.com/leanprover/lean4/pull/5732) renames `List.pure` to `List.singleton`.
-  * [#5742](https://github.com/leanprover/lean4/pull/5742) upstreams `ne_of_mem_of_not_mem`.
-  * [#5743](https://github.com/leanprover/lean4/pull/5743) upstreams `ne_of_apply_ne`.
-  * [#5816](https://github.com/leanprover/lean4/pull/5816) adds more `List.modify` lemmas.
-  * [#5879](https://github.com/leanprover/lean4/pull/5879) renames `List.groupBy` to `splitBy`.
-  * [#5913](https://github.com/leanprover/lean4/pull/5913) relates `for` loops over `List` with `foldlM`.
-
-* `Nat`
-  * [#5694](https://github.com/leanprover/lean4/pull/5694) removes `instBEqNat`, which is redundant with `instBEqOfDecidableEq` but not defeq.
-  * [#5746](https://github.com/leanprover/lean4/pull/5746) deprecates `Nat.sum`.
-  * [#5785](https://github.com/leanprover/lean4/pull/5785) adds `Nat.forall_lt_succ` and variants.
-
-* Fixed width integers
-  * [#5323](https://github.com/leanprover/lean4/pull/5323) redefine unsigned fixed width integers in terms of `BitVec`.
-  * [#5735](https://github.com/leanprover/lean4/pull/5735) adds `UIntX.[val_ofNat, toBitVec_ofNat]`.
-  * [#5790](https://github.com/leanprover/lean4/pull/5790) defines `Int8`.
-  * [#5901](https://github.com/leanprover/lean4/pull/5901) removes native code for `UInt8.modn`.
-
-* `BitVec`
-  * [#5604](https://github.com/leanprover/lean4/pull/5604) completes `BitVec.[getMsbD|getLsbD|msb]` for shifts (@luisacicolini).
-  * [#5609](https://github.com/leanprover/lean4/pull/5609) adds lemmas for division when denominator is zero (@bollu).
-  * [#5620](https://github.com/leanprover/lean4/pull/5620) documents Bitblasting (@bollu)
-  * [#5623](https://github.com/leanprover/lean4/pull/5623) moves `BitVec.udiv/umod/sdiv/smod` after `add/sub/mul/lt` (@tobiasgrosser).
-  * [#5645](https://github.com/leanprover/lean4/pull/5645) defines `udiv` normal form to be `/`, resp. `umod` and `%` (@bollu).
-  * [#5646](https://github.com/leanprover/lean4/pull/5646) adds lemmas about arithmetic inequalities (@bollu).
-  * [#5680](https://github.com/leanprover/lean4/pull/5680) expands relationship with `toFin` (@tobiasgrosser).
-  * [#5691](https://github.com/leanprover/lean4/pull/5691) adds `BitVec.(getMSbD, msb)_(add, sub)` and `BitVec.getLsbD_sub` (@luisacicolini).
-  * [#5712](https://github.com/leanprover/lean4/pull/5712) adds `BitVec.[udiv|umod]_[zero|one|self]` (@tobiasgrosser).
-  * [#5718](https://github.com/leanprover/lean4/pull/5718) adds `BitVec.sdiv_[zero|one|self]` (@tobiasgrosser).
-  * [#5721](https://github.com/leanprover/lean4/pull/5721) adds `BitVec.(msb, getMsbD, getLsbD)_(neg, abs)` (@luisacicolini).
-  * [#5772](https://github.com/leanprover/lean4/pull/5772) adds `BitVec.toInt_sub`, simplifies `BitVec.toInt_neg` (@tobiasgrosser).
-  * [#5778](https://github.com/leanprover/lean4/pull/5778) prove that `intMin` the smallest signed bitvector (@alexkeizer).
-  * [#5851](https://github.com/leanprover/lean4/pull/5851) adds `(msb, getMsbD)_twoPow` (@luisacicolini).
-  * [#5858](https://github.com/leanprover/lean4/pull/5858) adds `BitVec.[zero_ushiftRight|zero_sshiftRight|zero_mul]` and cleans up BVDecide (@tobiasgrosser).
-  * [#5865](https://github.com/leanprover/lean4/pull/5865) adds `BitVec.(msb, getMsbD)_concat` (@luisacicolini).
-  * [#5881](https://github.com/leanprover/lean4/pull/5881) adds `Hashable (BitVec n)`
-
-* `String`/`Char`
-  * [#5728](https://github.com/leanprover/lean4/pull/5728) upstreams `String.dropPrefix?`.
-  * [#5745](https://github.com/leanprover/lean4/pull/5745) changes `String.dropPrefix?` signature.
-  * [#5747](https://github.com/leanprover/lean4/pull/5747) adds `Hashable Char` instance
-
-* `HashMap`
-  * [#5880](https://github.com/leanprover/lean4/pull/5880) adds interim implementation of `HashMap.modify`/`alter`
-
-* **Other**
-  * [#5704](https://github.com/leanprover/lean4/pull/5704) removes `@[simp]` from `Option.isSome_eq_isSome`.
-  * [#5739](https://github.com/leanprover/lean4/pull/5739) upstreams material on `Prod`.
-  * [#5740](https://github.com/leanprover/lean4/pull/5740) moves `Antisymm` to `Std.Antisymm`.
-  * [#5741](https://github.com/leanprover/lean4/pull/5741) upstreams basic material on `Sum`.
-  * [#5756](https://github.com/leanprover/lean4/pull/5756) adds `Nat.log2_two_pow` (@spinylobster).
-  * [#5892](https://github.com/leanprover/lean4/pull/5892) removes duplicated `ForIn` instances.
-  * [#5900](https://github.com/leanprover/lean4/pull/5900) removes `@[simp]` from `Sum.forall` and `Sum.exists`.
-  * [#5812](https://github.com/leanprover/lean4/pull/5812) removes redundant `Decidable` assumptions (@FR-vdash-bot).
-
-### Compiler, runtime, and FFI
-
-* [#5685](https://github.com/leanprover/lean4/pull/5685) fixes help message flags, removes the `-f` flag and adds the `-g` flag (@James-Oswald).
-* [#5930](https://github.com/leanprover/lean4/pull/5930) adds `--short-version` (`-V`) option to display short version (@juhp).
-* [#5144](https://github.com/leanprover/lean4/pull/5144) switches all 64-bit platforms over to consistently using GMP for bignum arithmetic.
-* [#5753](https://github.com/leanprover/lean4/pull/5753) raises the minimum supported Windows version to Windows 10 1903 (released May 2019).
-
-### Lake
-
-* [#5715](https://github.com/leanprover/lean4/pull/5715) changes `lake new math` to use `autoImplicit false` (@eric-wieser).
-* [#5688](https://github.com/leanprover/lean4/pull/5688) makes `Lake` not create core aliases in the `Lake` namespace.
-* [#5924](https://github.com/leanprover/lean4/pull/5924) adds a `text` option for `buildFile*` utilities.
-* [#5789](https://github.com/leanprover/lean4/pull/5789) makes `lake init` not `git init` when inside git work tree (@haoxins).
-* [#5684](https://github.com/leanprover/lean4/pull/5684) has Lake update a package's `lean-toolchain` file on `lake update` if it finds the package's direct dependencies use a newer compatible toolchain. To skip this step, use the `--keep-toolchain` CLI option. (See breaking changes.)
-* [#6218](https://github.com/leanprover/lean4/pull/6218) makes Lake no longer automatically fetch GitHub cloud releases if the package build directory is already present (mirroring the behavior of the Reservoir cache). This prevents the cache from clobbering existing prebuilt artifacts. Users can still manually fetch the cache and clobber the build directory by running `lake build <pkg>:release`.
-* [#6231](https://github.com/leanprover/lean4/pull/6231) improves the errors Lake produces when it fails to fetch a dependency from Reservoir. If the package is not indexed, it will produce a suggestion about how to require it from GitHub.
-
-### Documentation
-
-* [#5617](https://github.com/leanprover/lean4/pull/5617) fixes MSYS2 build instructions.
-* [#5725](https://github.com/leanprover/lean4/pull/5725) points out that `OfScientific` is called with raw literals (@eric-wieser).
-* [#5794](https://github.com/leanprover/lean4/pull/5794) adds a stub for application ellipsis notation (@eric-wieser).
-
-### Breaking changes
-
-* The syntax for providing arguments to deriving handlers has been removed, which was not used by any major Lean projects in the ecosystem. As a result, the  `applyDerivingHandlers` now takes one fewer argument, `registerDerivingHandlerWithArgs` is now simply `registerDerivingHandler`, `DerivingHandler` no longer includes the unused parameter, and `DerivingHandlerNoArgs` has been deprecated. To migrate code, delete the unused `none` argument and use `registerDerivingHandler` and `DerivingHandler`. ([#5265](https://github.com/leanprover/lean4/pull/5265))
-* The minimum supported Windows version has been raised to Windows 10 1903, released May 2019. ([#5753](https://github.com/leanprover/lean4/pull/5753))
-* The `--lean` CLI option for `lake` was removed. Use the `LEAN` environment variable instead. ([#5684](https://github.com/leanprover/lean4/pull/5684))
-* The `inductive ... :=`, `structure ... :=`, and `class ... :=` syntaxes have been deprecated in favor of the `... where` variants. The old syntax produces a warning, controlled by the `linter.deprecated` option. ([#5542](https://github.com/leanprover/lean4/pull/5542))
-* The generated tactic configuration elaborators now land in `TacticM` to make use of the current recovery state. Commands that wish to elaborate configurations should now use `declare_command_config_elab` instead of `declare_config_elab` to get an elaborator landing in `CommandElabM`. Syntaxes should migrate to `optConfig` instead of `(config)?`, but the elaborators are reverse compatible. ([#5883](https://github.com/leanprover/lean4/pull/5883))
-
-
-v4.13.0
-----------
-
-**Full Changelog**: https://github.com/leanprover/lean4/compare/v4.12.0...v4.13.0
-
-### Language features, tactics, and metaprograms
-
-* `structure` command
-  * [#5511](https://github.com/leanprover/lean4/pull/5511) allows structure parents to be type synonyms.
-  * [#5531](https://github.com/leanprover/lean4/pull/5531) allows default values for structure fields to be noncomputable.
-
-* `rfl` and `apply_rfl` tactics
-  * [#3714](https://github.com/leanprover/lean4/pull/3714), [#3718](https://github.com/leanprover/lean4/pull/3718) improve the `rfl` tactic and give better error messages.
-  * [#3772](https://github.com/leanprover/lean4/pull/3772) makes `rfl` no longer use kernel defeq for ground terms.
-  * [#5329](https://github.com/leanprover/lean4/pull/5329) tags `Iff.refl` with `@[refl]` (@Parcly-Taxel)
-  * [#5359](https://github.com/leanprover/lean4/pull/5359) ensures that the `rfl` tactic tries `Iff.rfl` (@Parcly-Taxel)
-
-* `unfold` tactic
-  * [#4834](https://github.com/leanprover/lean4/pull/4834) let `unfold` do zeta-delta reduction of local definitions, incorporating functionality of the Mathlib `unfold_let` tactic.
-
-* `omega` tactic
-  * [#5382](https://github.com/leanprover/lean4/pull/5382) fixes spurious error in [#5315](https://github.com/leanprover/lean4/issues/5315)
-  * [#5523](https://github.com/leanprover/lean4/pull/5523) supports `Int.toNat`
-
-* `simp` tactic
-  * [#5479](https://github.com/leanprover/lean4/pull/5479) lets `simp` apply rules with higher-order patterns.
-
-* `induction` tactic
-  * [#5494](https://github.com/leanprover/lean4/pull/5494) fixes `induction`’s "pre-tactic" block to always be indented, avoiding unintended uses of it.
-
-* `ac_nf` tactic
-  * [#5524](https://github.com/leanprover/lean4/pull/5524) adds `ac_nf`, a counterpart to `ac_rfl`, for normalizing expressions with respect to associativity and commutativity. Tests it with `BitVec` expressions.
-
-* `bv_decide`
-  * [#5211](https://github.com/leanprover/lean4/pull/5211) makes `extractLsb'` the primitive `bv_decide` understands, rather than `extractLsb` (@alexkeizer)
-  * [#5365](https://github.com/leanprover/lean4/pull/5365) adds `bv_decide` diagnoses.
-  * [#5375](https://github.com/leanprover/lean4/pull/5375) adds `bv_decide` normalization rules for `ofBool (a.getLsbD i)` and `ofBool a[i]` (@alexkeizer)
-  * [#5423](https://github.com/leanprover/lean4/pull/5423) enhances the rewriting rules of `bv_decide`
-  * [#5433](https://github.com/leanprover/lean4/pull/5433) presents the `bv_decide` counterexample at the API
-  * [#5484](https://github.com/leanprover/lean4/pull/5484) handles `BitVec.ofNat` with `Nat` fvars in `bv_decide`
-  * [#5506](https://github.com/leanprover/lean4/pull/5506), [#5507](https://github.com/leanprover/lean4/pull/5507) add `bv_normalize` rules.
-  * [#5568](https://github.com/leanprover/lean4/pull/5568) generalize the `bv_normalize` pipeline to support more general preprocessing passes
-  * [#5573](https://github.com/leanprover/lean4/pull/5573) gets `bv_normalize` up-to-date with the current `BitVec` rewrites
-  * Cleanups: [#5408](https://github.com/leanprover/lean4/pull/5408), [#5493](https://github.com/leanprover/lean4/pull/5493), [#5578](https://github.com/leanprover/lean4/pull/5578)
-
-
-* Elaboration improvements
-  * [#5266](https://github.com/leanprover/lean4/pull/5266) preserve order of overapplied arguments in `elab_as_elim` procedure.
-  * [#5510](https://github.com/leanprover/lean4/pull/5510) generalizes `elab_as_elim` to allow arbitrary motive applications.
-  * [#5283](https://github.com/leanprover/lean4/pull/5283), [#5512](https://github.com/leanprover/lean4/pull/5512) refine how named arguments suppress explicit arguments. Breaking change: some previously omitted explicit arguments may need explicit `_` arguments now.
-  * [#5376](https://github.com/leanprover/lean4/pull/5376) modifies projection instance binder info for instances, making parameters that are instance implicit in the type be implicit.
-  * [#5402](https://github.com/leanprover/lean4/pull/5402) localizes universe metavariable errors to `let` bindings and `fun` binders if possible. Makes "cannot synthesize metavariable" errors take precedence over unsolved universe level errors.
-  * [#5419](https://github.com/leanprover/lean4/pull/5419) must not reduce `ite` in the discriminant of `match`-expression when reducibility setting is `.reducible`
-  * [#5474](https://github.com/leanprover/lean4/pull/5474) have autoparams report parameter/field on failure
-  * [#5530](https://github.com/leanprover/lean4/pull/5530) makes automatic instance names about types with hygienic names be hygienic.
-
-* Deriving handlers
-  * [#5432](https://github.com/leanprover/lean4/pull/5432) makes `Repr` deriving instance handle explicit type parameters
-
-* Functional induction
-  * [#5364](https://github.com/leanprover/lean4/pull/5364) adds more equalities in context, more careful cleanup.
-
-* Linters
-  * [#5335](https://github.com/leanprover/lean4/pull/5335) fixes the unused variables linter complaining about match/tactic combinations
-  * [#5337](https://github.com/leanprover/lean4/pull/5337) fixes the unused variables linter complaining about some wildcard patterns
-
-* Other fixes
-  * [#4768](https://github.com/leanprover/lean4/pull/4768) fixes a parse error when `..` appears with a `.` on the next line
-
-* Metaprogramming
-  * [#3090](https://github.com/leanprover/lean4/pull/3090) handles level parameters in `Meta.evalExpr` (@eric-wieser)
-  * [#5401](https://github.com/leanprover/lean4/pull/5401) instance for `Inhabited (TacticM α)` (@alexkeizer)
-  * [#5412](https://github.com/leanprover/lean4/pull/5412) expose Kernel.check for debugging purposes
-  * [#5556](https://github.com/leanprover/lean4/pull/5556) improves the "invalid projection" type inference error in `inferType`.
-  * [#5587](https://github.com/leanprover/lean4/pull/5587) allows `MVarId.assertHypotheses` to set `BinderInfo` and `LocalDeclKind`.
-  * [#5588](https://github.com/leanprover/lean4/pull/5588) adds `MVarId.tryClearMany'`, a variant of `MVarId.tryClearMany`.
-
-
-
-### Language server, widgets, and IDE extensions
-
-* [#5205](https://github.com/leanprover/lean4/pull/5205) decreases the latency of auto-completion in tactic blocks.
-* [#5237](https://github.com/leanprover/lean4/pull/5237) fixes symbol occurrence highlighting in VS Code not highlighting occurrences when moving the text cursor into the identifier from the right.
-* [#5257](https://github.com/leanprover/lean4/pull/5257) fixes several instances of incorrect auto-completions being reported.
-* [#5299](https://github.com/leanprover/lean4/pull/5299) allows auto-completion to report completions for global identifiers when the elaborator fails to provide context-specific auto-completions.
-* [#5312](https://github.com/leanprover/lean4/pull/5312) fixes the server breaking when changing whitespace after the module header.
-* [#5322](https://github.com/leanprover/lean4/pull/5322) fixes several instances of auto-completion reporting non-existent namespaces.
-* [#5428](https://github.com/leanprover/lean4/pull/5428) makes sure to always report some recent file range as progress when waiting for elaboration.
-
-
-### Pretty printing
-
-* [#4979](https://github.com/leanprover/lean4/pull/4979) make pretty printer escape identifiers that are tokens.
-* [#5389](https://github.com/leanprover/lean4/pull/5389) makes formatter use the current token table.
-* [#5513](https://github.com/leanprover/lean4/pull/5513) use breakable instead of unbreakable whitespace when formatting tokens.
-
-
-### Library
-
-* [#5222](https://github.com/leanprover/lean4/pull/5222) reduces allocations in `Json.compress`.
-* [#5231](https://github.com/leanprover/lean4/pull/5231) upstreams `Zero` and `NeZero`
-* [#5292](https://github.com/leanprover/lean4/pull/5292) refactors `Lean.Elab.Deriving.FromToJson` (@arthur-adjedj)
-* [#5415](https://github.com/leanprover/lean4/pull/5415) implements `Repr Empty` (@TomasPuverle)
-* [#5421](https://github.com/leanprover/lean4/pull/5421) implements `To/FromJSON Empty` (@TomasPuverle)
-
-* Logic
-  * [#5263](https://github.com/leanprover/lean4/pull/5263) allows simplifying `dite_not`/`decide_not` with only `Decidable (¬p)`.
-  * [#5268](https://github.com/leanprover/lean4/pull/5268) fixes binders on `ite_eq_left_iff`
-  * [#5284](https://github.com/leanprover/lean4/pull/5284) turns off `Inhabited (Sum α β)` instances
-  * [#5355](https://github.com/leanprover/lean4/pull/5355) adds simp lemmas for `LawfulBEq`
-  * [#5374](https://github.com/leanprover/lean4/pull/5374) add `Nonempty` instances for products, allowing more `partial` functions to elaborate successfully
-  * [#5447](https://github.com/leanprover/lean4/pull/5447) updates Pi instance names
-  * [#5454](https://github.com/leanprover/lean4/pull/5454) makes some instance arguments implicit
-  * [#5456](https://github.com/leanprover/lean4/pull/5456) adds `heq_comm`
-  * [#5529](https://github.com/leanprover/lean4/pull/5529) moves `@[simp]` from `exists_prop'` to `exists_prop`
-
-* `Bool`
-  * [#5228](https://github.com/leanprover/lean4/pull/5228) fills gaps in Bool lemmas
-  * [#5332](https://github.com/leanprover/lean4/pull/5332) adds notation `^^` for Bool.xor
-  * [#5351](https://github.com/leanprover/lean4/pull/5351) removes `_root_.and` (and or/not/xor) and instead exports/uses `Bool.and` (etc.).
-
-* `BitVec`
-  * [#5240](https://github.com/leanprover/lean4/pull/5240) removes BitVec simps with complicated RHS
-  * [#5247](https://github.com/leanprover/lean4/pull/5247) `BitVec.getElem_zeroExtend`
-  * [#5248](https://github.com/leanprover/lean4/pull/5248) simp lemmas for BitVec, improving confluence
-  * [#5249](https://github.com/leanprover/lean4/pull/5249) removes `@[simp]` from some BitVec lemmas
-  * [#5252](https://github.com/leanprover/lean4/pull/5252) changes `BitVec.intMin/Max` from abbrev to def
-  * [#5278](https://github.com/leanprover/lean4/pull/5278) adds `BitVec.getElem_truncate` (@tobiasgrosser)
-  * [#5281](https://github.com/leanprover/lean4/pull/5281) adds udiv/umod bitblasting for `bv_decide` (@bollu)
-  * [#5297](https://github.com/leanprover/lean4/pull/5297) `BitVec` unsigned order theoretic results
-  * [#5313](https://github.com/leanprover/lean4/pull/5313) adds more basic BitVec ordering theory for UInt
-  * [#5314](https://github.com/leanprover/lean4/pull/5314) adds `toNat_sub_of_le` (@bollu)
-  * [#5357](https://github.com/leanprover/lean4/pull/5357) adds `BitVec.truncate` lemmas
-  * [#5358](https://github.com/leanprover/lean4/pull/5358) introduces `BitVec.setWidth` to unify zeroExtend and truncate (@tobiasgrosser)
-  * [#5361](https://github.com/leanprover/lean4/pull/5361) some BitVec GetElem lemmas
-  * [#5385](https://github.com/leanprover/lean4/pull/5385) adds `BitVec.ofBool_[and|or|xor]_ofBool` theorems (@tobiasgrosser)
-  * [#5404](https://github.com/leanprover/lean4/pull/5404) more of `BitVec.getElem_*` (@tobiasgrosser)
-  * [#5410](https://github.com/leanprover/lean4/pull/5410) BitVec analogues of `Nat.{mul_two, two_mul, mul_succ, succ_mul}` (@bollu)
-  * [#5411](https://github.com/leanprover/lean4/pull/5411) `BitVec.toNat_{add,sub,mul_of_lt}` for BitVector non-overflow reasoning (@bollu)
-  * [#5413](https://github.com/leanprover/lean4/pull/5413) adds `_self`, `_zero`, and `_allOnes` for `BitVec.[and|or|xor]` (@tobiasgrosser)
-  * [#5416](https://github.com/leanprover/lean4/pull/5416) adds LawCommIdentity + IdempotentOp for `BitVec.[and|or|xor]` (@tobiasgrosser)
-  * [#5418](https://github.com/leanprover/lean4/pull/5418) decidable quantifers for BitVec
-  * [#5450](https://github.com/leanprover/lean4/pull/5450) adds `BitVec.toInt_[intMin|neg|neg_of_ne_intMin]` (@tobiasgrosser)
-  * [#5459](https://github.com/leanprover/lean4/pull/5459) missing BitVec lemmas
-  * [#5469](https://github.com/leanprover/lean4/pull/5469) adds `BitVec.[not_not, allOnes_shiftLeft_or_shiftLeft, allOnes_shiftLeft_and_shiftLeft]` (@luisacicolini)
-  * [#5478](https://github.com/leanprover/lean4/pull/5478) adds `BitVec.(shiftLeft_add_distrib, shiftLeft_ushiftRight)` (@luisacicolini)
-  * [#5487](https://github.com/leanprover/lean4/pull/5487) adds `sdiv_eq`, `smod_eq` to allow `sdiv`/`smod` bitblasting (@bollu)
-  * [#5491](https://github.com/leanprover/lean4/pull/5491) adds `BitVec.toNat_[abs|sdiv|smod]` (@tobiasgrosser)
-  * [#5492](https://github.com/leanprover/lean4/pull/5492) `BitVec.(not_sshiftRight, not_sshiftRight_not, getMsb_not, msb_not)` (@luisacicolini)
-  * [#5499](https://github.com/leanprover/lean4/pull/5499) `BitVec.Lemmas` - drop non-terminal simps (@tobiasgrosser)
-  * [#5505](https://github.com/leanprover/lean4/pull/5505) unsimps `BitVec.divRec_succ'`
-  * [#5508](https://github.com/leanprover/lean4/pull/5508) adds `BitVec.getElem_[add|add_add_bool|mul|rotateLeft|rotateRight…` (@tobiasgrosser)
-  * [#5554](https://github.com/leanprover/lean4/pull/5554) adds `Bitvec.[add, sub, mul]_eq_xor` and `width_one_cases` (@luisacicolini)
-
-* `List`
-  * [#5242](https://github.com/leanprover/lean4/pull/5242) improve naming for `List.mergeSort` lemmas
-  * [#5302](https://github.com/leanprover/lean4/pull/5302) provide `mergeSort` comparator autoParam
-  * [#5373](https://github.com/leanprover/lean4/pull/5373) fix name of `List.length_mergeSort`
-  * [#5377](https://github.com/leanprover/lean4/pull/5377) upstream `map_mergeSort`
-  * [#5378](https://github.com/leanprover/lean4/pull/5378) modify signature of lemmas about `mergeSort`
-  * [#5245](https://github.com/leanprover/lean4/pull/5245) avoid importing `List.Basic` without List.Impl
-  * [#5260](https://github.com/leanprover/lean4/pull/5260) review of List API
-  * [#5264](https://github.com/leanprover/lean4/pull/5264) review of List API
-  * [#5269](https://github.com/leanprover/lean4/pull/5269) remove HashMap's duplicated Pairwise and Sublist
-  * [#5271](https://github.com/leanprover/lean4/pull/5271) remove @[simp] from `List.head_mem` and similar
-  * [#5273](https://github.com/leanprover/lean4/pull/5273) lemmas about `List.attach`
-  * [#5275](https://github.com/leanprover/lean4/pull/5275) reverse direction of `List.tail_map`
-  * [#5277](https://github.com/leanprover/lean4/pull/5277) more `List.attach` lemmas
-  * [#5285](https://github.com/leanprover/lean4/pull/5285) `List.count` lemmas
-  * [#5287](https://github.com/leanprover/lean4/pull/5287) use boolean predicates in `List.filter`
-  * [#5289](https://github.com/leanprover/lean4/pull/5289) `List.mem_ite_nil_left` and analogues
-  * [#5293](https://github.com/leanprover/lean4/pull/5293) cleanup of `List.findIdx` / `List.take` lemmas
-  * [#5294](https://github.com/leanprover/lean4/pull/5294) switch primes on `List.getElem_take`
-  * [#5300](https://github.com/leanprover/lean4/pull/5300) more `List.findIdx` theorems
-  * [#5310](https://github.com/leanprover/lean4/pull/5310) fix `List.all/any` lemmas
-  * [#5311](https://github.com/leanprover/lean4/pull/5311) fix `List.countP` lemmas
-  * [#5316](https://github.com/leanprover/lean4/pull/5316) `List.tail` lemma
-  * [#5331](https://github.com/leanprover/lean4/pull/5331) fix implicitness of `List.getElem_mem`
-  * [#5350](https://github.com/leanprover/lean4/pull/5350) `List.replicate` lemmas
-  * [#5352](https://github.com/leanprover/lean4/pull/5352) `List.attachWith` lemmas
-  * [#5353](https://github.com/leanprover/lean4/pull/5353) `List.head_mem_head?`
-  * [#5360](https://github.com/leanprover/lean4/pull/5360) lemmas about `List.tail`
-  * [#5391](https://github.com/leanprover/lean4/pull/5391) review of `List.erase` / `List.find` lemmas
-  * [#5392](https://github.com/leanprover/lean4/pull/5392) `List.fold` / `attach` lemmas
-  * [#5393](https://github.com/leanprover/lean4/pull/5393) `List.fold` relators
-  * [#5394](https://github.com/leanprover/lean4/pull/5394) lemmas about `List.maximum?`
-  * [#5403](https://github.com/leanprover/lean4/pull/5403) theorems about `List.toArray`
-  * [#5405](https://github.com/leanprover/lean4/pull/5405) reverse direction of `List.set_map`
-  * [#5448](https://github.com/leanprover/lean4/pull/5448) add lemmas about `List.IsPrefix` (@Command-Master)
-  * [#5460](https://github.com/leanprover/lean4/pull/5460) missing `List.set_replicate_self`
-  * [#5518](https://github.com/leanprover/lean4/pull/5518) rename `List.maximum?` to `max?`
-  * [#5519](https://github.com/leanprover/lean4/pull/5519) upstream `List.fold` lemmas
-  * [#5520](https://github.com/leanprover/lean4/pull/5520) restore `@[simp]` on `List.getElem_mem` etc.
-  * [#5521](https://github.com/leanprover/lean4/pull/5521) List simp fixes
-  * [#5550](https://github.com/leanprover/lean4/pull/5550) `List.unattach` and simp lemmas
-  * [#5594](https://github.com/leanprover/lean4/pull/5594) induction-friendly `List.min?_cons`
-
-* `Array`
-  * [#5246](https://github.com/leanprover/lean4/pull/5246) cleanup imports of Array.Lemmas
-  * [#5255](https://github.com/leanprover/lean4/pull/5255) split Init.Data.Array.Lemmas for better bootstrapping
-  * [#5288](https://github.com/leanprover/lean4/pull/5288) rename `Array.data` to `Array.toList`
-  * [#5303](https://github.com/leanprover/lean4/pull/5303) cleanup of `List.getElem_append` variants
-  * [#5304](https://github.com/leanprover/lean4/pull/5304) `Array.not_mem_empty`
-  * [#5400](https://github.com/leanprover/lean4/pull/5400) reorganization in Array/Basic
-  * [#5420](https://github.com/leanprover/lean4/pull/5420) make `Array` functions either semireducible or use structural recursion
-  * [#5422](https://github.com/leanprover/lean4/pull/5422) refactor `DecidableEq (Array α)`
-  * [#5452](https://github.com/leanprover/lean4/pull/5452) refactor of Array
-  * [#5458](https://github.com/leanprover/lean4/pull/5458) cleanup of Array docstrings after refactor
-  * [#5461](https://github.com/leanprover/lean4/pull/5461) restore `@[simp]` on `Array.swapAt!_def`
-  * [#5465](https://github.com/leanprover/lean4/pull/5465) improve Array GetElem lemmas
-  * [#5466](https://github.com/leanprover/lean4/pull/5466) `Array.foldX` lemmas
-  * [#5472](https://github.com/leanprover/lean4/pull/5472) @[simp] lemmas about `List.toArray`
-  * [#5485](https://github.com/leanprover/lean4/pull/5485) reverse simp direction for `toArray_concat`
-  * [#5514](https://github.com/leanprover/lean4/pull/5514) `Array.eraseReps`
-  * [#5515](https://github.com/leanprover/lean4/pull/5515) upstream `Array.qsortOrd`
-  * [#5516](https://github.com/leanprover/lean4/pull/5516) upstream `Subarray.empty`
-  * [#5526](https://github.com/leanprover/lean4/pull/5526) fix name of `Array.length_toList`
-  * [#5527](https://github.com/leanprover/lean4/pull/5527) reduce use of deprecated lemmas in Array
-  * [#5534](https://github.com/leanprover/lean4/pull/5534) cleanup of Array GetElem lemmas
-  * [#5536](https://github.com/leanprover/lean4/pull/5536) fix `Array.modify` lemmas
-  * [#5551](https://github.com/leanprover/lean4/pull/5551) upstream `Array.flatten` lemmas
-  * [#5552](https://github.com/leanprover/lean4/pull/5552) switch obvious cases of array "bang"`[]!` indexing to rely on hypothesis (@TomasPuverle)
-  * [#5577](https://github.com/leanprover/lean4/pull/5577) add missing simp to `Array.size_feraseIdx`
-  * [#5586](https://github.com/leanprover/lean4/pull/5586) `Array/Option.unattach`
-
-* `Option`
-  * [#5272](https://github.com/leanprover/lean4/pull/5272) remove @[simp] from `Option.pmap/pbind` and add simp lemmas
-  * [#5307](https://github.com/leanprover/lean4/pull/5307) restoring Option simp confluence
-  * [#5354](https://github.com/leanprover/lean4/pull/5354) remove @[simp] from `Option.bind_map`
-  * [#5532](https://github.com/leanprover/lean4/pull/5532) `Option.attach`
-  * [#5539](https://github.com/leanprover/lean4/pull/5539) fix explicitness of `Option.mem_toList`
-
-* `Nat`
-  * [#5241](https://github.com/leanprover/lean4/pull/5241) add @[simp] to `Nat.add_eq_zero_iff`
-  * [#5261](https://github.com/leanprover/lean4/pull/5261) Nat bitwise lemmas
-  * [#5262](https://github.com/leanprover/lean4/pull/5262) `Nat.testBit_add_one` should not be a global simp lemma
-  * [#5267](https://github.com/leanprover/lean4/pull/5267) protect some Nat bitwise theorems
-  * [#5305](https://github.com/leanprover/lean4/pull/5305) rename Nat bitwise lemmas
-  * [#5306](https://github.com/leanprover/lean4/pull/5306) add `Nat.self_sub_mod` lemma
-  * [#5503](https://github.com/leanprover/lean4/pull/5503) restore @[simp] to upstreamed `Nat.lt_off_iff`
-
-* `Int`
-  * [#5301](https://github.com/leanprover/lean4/pull/5301) rename `Int.div/mod` to `Int.tdiv/tmod`
-  * [#5320](https://github.com/leanprover/lean4/pull/5320) add `ediv_nonneg_of_nonpos_of_nonpos` to DivModLemmas (@sakehl)
-
-* `Fin`
-  * [#5250](https://github.com/leanprover/lean4/pull/5250) missing lemma about `Fin.ofNat'`
-  * [#5356](https://github.com/leanprover/lean4/pull/5356) `Fin.ofNat'` uses `NeZero`
-  * [#5379](https://github.com/leanprover/lean4/pull/5379) remove some @[simp]s from Fin lemmas
-  * [#5380](https://github.com/leanprover/lean4/pull/5380) missing Fin @[simp] lemmas
-
-* `HashMap`
-  * [#5244](https://github.com/leanprover/lean4/pull/5244) (`DHashMap`|`HashMap`|`HashSet`).(`getKey?`|`getKey`|`getKey!`|`getKeyD`)
-  * [#5362](https://github.com/leanprover/lean4/pull/5362) remove the last use of `Lean.(HashSet|HashMap)`
-  * [#5369](https://github.com/leanprover/lean4/pull/5369) `HashSet.ofArray`
-  * [#5370](https://github.com/leanprover/lean4/pull/5370) `HashSet.partition`
-  * [#5581](https://github.com/leanprover/lean4/pull/5581) `Singleton`/`Insert`/`Union` instances for `HashMap`/`Set`
-  * [#5582](https://github.com/leanprover/lean4/pull/5582) `HashSet.all`/`any`
-  * [#5590](https://github.com/leanprover/lean4/pull/5590) adding `Insert`/`Singleton`/`Union` instances for `HashMap`/`Set.Raw`
-  * [#5591](https://github.com/leanprover/lean4/pull/5591) `HashSet.Raw.all/any`
-
-* `Monads`
-  * [#5463](https://github.com/leanprover/lean4/pull/5463) upstream some monad lemmas
-  * [#5464](https://github.com/leanprover/lean4/pull/5464) adjust simp attributes on monad lemmas
-  * [#5522](https://github.com/leanprover/lean4/pull/5522) more monadic simp lemmas
-
-* Simp lemma cleanup
-  * [#5251](https://github.com/leanprover/lean4/pull/5251) remove redundant simp annotations
-  * [#5253](https://github.com/leanprover/lean4/pull/5253) remove Int simp lemmas that can't fire
-  * [#5254](https://github.com/leanprover/lean4/pull/5254) variables appearing on both sides of an iff should be implicit
-  * [#5381](https://github.com/leanprover/lean4/pull/5381) cleaning up redundant simp lemmas
-
-
-### Compiler, runtime, and FFI
-
-* [#4685](https://github.com/leanprover/lean4/pull/4685) fixes a typo in the C `run_new_frontend` signature
-* [#4729](https://github.com/leanprover/lean4/pull/4729) has IR checker suggest using `noncomputable`
-* [#5143](https://github.com/leanprover/lean4/pull/5143) adds a shared library for Lake
-* [#5437](https://github.com/leanprover/lean4/pull/5437) removes (syntactically) duplicate imports (@euprunin)
-* [#5462](https://github.com/leanprover/lean4/pull/5462) updates `src/lake/lakefile.toml` to the adjusted Lake build process
-* [#5541](https://github.com/leanprover/lean4/pull/5541) removes new shared libs before build to better support Windows
-* [#5558](https://github.com/leanprover/lean4/pull/5558) make `lean.h` compile with MSVC (@kant2002)
-* [#5564](https://github.com/leanprover/lean4/pull/5564) removes non-conforming size-0 arrays (@eric-wieser)
-
-
-### Lake
-  * Reservoir build cache. Lake will now attempt to fetch a pre-built copy of the package from Reservoir before building it. This is only enabled for packages in the leanprover or leanprover-community organizations on versions indexed by Reservoir. Users can force Lake to build packages from the source by passing --no-cache on the CLI or by setting the  LAKE_NO_CACHE environment variable to true. [#5486](https://github.com/leanprover/lean4/pull/5486), [#5572](https://github.com/leanprover/lean4/pull/5572), [#5583](https://github.com/leanprover/lean4/pull/5583), [#5600](https://github.com/leanprover/lean4/pull/5600), [#5641](https://github.com/leanprover/lean4/pull/5641), [#5642](https://github.com/leanprover/lean4/pull/5642).
-  * [#5504](https://github.com/leanprover/lean4/pull/5504) lake new and lake init now produce TOML configurations by default.
-  * [#5878](https://github.com/leanprover/lean4/pull/5878) fixes a serious issue where Lake would delete path dependencies when attempting to cleanup a dependency required with an incorrect name.
-
-  * **Breaking changes**
-    * [#5641](https://github.com/leanprover/lean4/pull/5641) A Lake build of target within a package will no longer build a package's dependencies package-level extra target dependencies. At the technical level, a package's extraDep facet no longer transitively builds its dependencies’ extraDep facets (which include their extraDepTargets).
-
-### Documentation fixes
-
-* [#3918](https://github.com/leanprover/lean4/pull/3918) `@[builtin_doc]` attribute (@digama0)
-* [#4305](https://github.com/leanprover/lean4/pull/4305) explains the borrow syntax (@eric-wieser)
-* [#5349](https://github.com/leanprover/lean4/pull/5349) adds documentation for `groupBy.loop` (@vihdzp)
-* [#5473](https://github.com/leanprover/lean4/pull/5473) fixes typo in `BitVec.mul` docstring (@llllvvuu)
-* [#5476](https://github.com/leanprover/lean4/pull/5476) fixes typos in `Lean.MetavarContext`
-* [#5481](https://github.com/leanprover/lean4/pull/5481) removes mention of `Lean.withSeconds` (@alexkeizer)
-* [#5497](https://github.com/leanprover/lean4/pull/5497) updates documentation and tests for `toUIntX` functions (@TomasPuverle)
-* [#5087](https://github.com/leanprover/lean4/pull/5087) mentions that `inferType` does not ensure type correctness
-* Many fixes to spelling across the doc-strings, (@euprunin): [#5425](https://github.com/leanprover/lean4/pull/5425) [#5426](https://github.com/leanprover/lean4/pull/5426) [#5427](https://github.com/leanprover/lean4/pull/5427) [#5430](https://github.com/leanprover/lean4/pull/5430)  [#5431](https://github.com/leanprover/lean4/pull/5431) [#5434](https://github.com/leanprover/lean4/pull/5434) [#5435](https://github.com/leanprover/lean4/pull/5435) [#5436](https://github.com/leanprover/lean4/pull/5436) [#5438](https://github.com/leanprover/lean4/pull/5438) [#5439](https://github.com/leanprover/lean4/pull/5439) [#5440](https://github.com/leanprover/lean4/pull/5440) [#5599](https://github.com/leanprover/lean4/pull/5599)
-
-### Changes to CI
-
-* [#5343](https://github.com/leanprover/lean4/pull/5343) allows addition of `release-ci` label via comment (@thorimur)
-* [#5344](https://github.com/leanprover/lean4/pull/5344) sets check level correctly during workflow (@thorimur)
-* [#5444](https://github.com/leanprover/lean4/pull/5444) Mathlib's `lean-pr-testing-NNNN` branches should use Batteries' `lean-pr-testing-NNNN` branches
-* [#5489](https://github.com/leanprover/lean4/pull/5489) commit `lake-manifest.json` when updating `lean-pr-testing` branches
-* [#5490](https://github.com/leanprover/lean4/pull/5490) use separate secrets for commenting and branching in `pr-release.yml`
-
 v4.12.0
 ----------
-
-### Language features, tactics, and metaprograms
-
-* `bv_decide` tactic. This release introduces a new tactic for proving goals involving `BitVec` and `Bool`. It reduces the goal to a SAT instance that is refuted by an external solver, and the resulting LRAT proof is checked in Lean. This is used to synthesize a proof of the goal by reflection. As this process uses verified algorithms, proofs generated by this tactic use `Lean.ofReduceBool`, so this tactic includes the Lean compiler as part of the trusted code base. The external solver CaDiCaL is included with Lean and does not need to be installed separately to make use of `bv_decide`.
-
-  For example, we can use `bv_decide` to verify that a bit twiddling formula leaves at most one bit set:
-  ```lean
-  def popcount (x : BitVec 64) : BitVec 64 :=
-    let rec go (x pop : BitVec 64) : Nat → BitVec 64
-      | 0 => pop
-      | n + 1 => go (x >>> 2) (pop + (x &&& 1)) n
-    go x 0 64
-
-  example (x : BitVec 64) : popcount ((x &&& (x - 1)) ^^^ x) ≤ 1 := by
-    simp only [popcount, popcount.go]
-    bv_decide
-  ```
-  When the external solver fails to refute the SAT instance generated by `bv_decide`, it can report a counterexample:
-  ```lean
-  /--
-  error: The prover found a counterexample, consider the following assignment:
-  x = 0xffffffffffffffff#64
-  -/
-  #guard_msgs in
-  example (x : BitVec 64) : x < x + 1 := by
-    bv_decide
-  ```
-
-  See `Lean.Elab.Tactic.BVDecide` for a more detailed overview, and look in `tests/lean/run/bv_*` for examples.
-
-  [#5013](https://github.com/leanprover/lean4/pull/5013), [#5074](https://github.com/leanprover/lean4/pull/5074), [#5100](https://github.com/leanprover/lean4/pull/5100), [#5113](https://github.com/leanprover/lean4/pull/5113), [#5137](https://github.com/leanprover/lean4/pull/5137), [#5203](https://github.com/leanprover/lean4/pull/5203), [#5212](https://github.com/leanprover/lean4/pull/5212), [#5220](https://github.com/leanprover/lean4/pull/5220).
-
-* `simp` tactic
-  * [#4988](https://github.com/leanprover/lean4/pull/4988) fixes a panic in the `reducePow` simproc.
-  * [#5071](https://github.com/leanprover/lean4/pull/5071) exposes the `index` option to the `dsimp` tactic, introduced to `simp` in [#4202](https://github.com/leanprover/lean4/pull/4202).
-  * [#5159](https://github.com/leanprover/lean4/pull/5159) fixes a panic at `Fin.isValue` simproc.
-  * [#5167](https://github.com/leanprover/lean4/pull/5167) and [#5175](https://github.com/leanprover/lean4/pull/5175) rename the `simpCtorEq` simproc to `reduceCtorEq` and makes it optional. (See breaking changes.)
-  * [#5187](https://github.com/leanprover/lean4/pull/5187) ensures `reduceCtorEq` is enabled in the `norm_cast` tactic.
-  * [#5073](https://github.com/leanprover/lean4/pull/5073) modifies the simp debug trace messages to tag with "dpre" and "dpost" instead of "pre" and "post" when in definitional rewrite mode. [#5054](https://github.com/leanprover/lean4/pull/5054) explains the `reduce` steps for `trace.Debug.Meta.Tactic.simp` trace messages.
-* `ext` tactic
-  * [#4996](https://github.com/leanprover/lean4/pull/4996) reduces default maximum iteration depth from 1000000 to 100.
-* `induction` tactic
-  * [#5117](https://github.com/leanprover/lean4/pull/5117) fixes a bug where `let` bindings in minor premises wouldn't be counted correctly.
-
-* `omega` tactic
-  * [#5157](https://github.com/leanprover/lean4/pull/5157) fixes a panic.
-
-* `conv` tactic
-  * [#5149](https://github.com/leanprover/lean4/pull/5149) improves `arg n` to handle subsingleton instance arguments.
-
-* [#5044](https://github.com/leanprover/lean4/pull/5044) upstreams the `#time` command.
-* [#5079](https://github.com/leanprover/lean4/pull/5079) makes `#check` and `#reduce` typecheck the elaborated terms.
-
-* **Incrementality**
-  * [#4974](https://github.com/leanprover/lean4/pull/4974) fixes regression where we would not interrupt elaboration of previous document versions.
-  * [#5004](https://github.com/leanprover/lean4/pull/5004) fixes a performance regression.
-  * [#5001](https://github.com/leanprover/lean4/pull/5001) disables incremental body elaboration in presence of `where` clauses in declarations.
-  * [#5018](https://github.com/leanprover/lean4/pull/5018) enables infotrees on the command line for ilean generation.
-  * [#5040](https://github.com/leanprover/lean4/pull/5040) and [#5056](https://github.com/leanprover/lean4/pull/5056) improve performance of info trees.
-  * [#5090](https://github.com/leanprover/lean4/pull/5090) disables incrementality in the `case .. | ..` tactic.
-  * [#5312](https://github.com/leanprover/lean4/pull/5312) fixes a bug where changing whitespace after the module header could break subsequent commands.
-
-* **Definitions**
-  * [#5016](https://github.com/leanprover/lean4/pull/5016) and [#5066](https://github.com/leanprover/lean4/pull/5066) add `clean_wf` tactic to clean up tactic state in `decreasing_by`. This can be disabled with `set_option debug.rawDecreasingByGoal false`.
-  * [#5055](https://github.com/leanprover/lean4/pull/5055) unifies equational theorems between structural and well-founded recursion.
-  * [#5041](https://github.com/leanprover/lean4/pull/5041) allows mutually recursive functions to use different parameter names among the “fixed parameter prefix”
-  * [#4154](https://github.com/leanprover/lean4/pull/4154) and [#5109](https://github.com/leanprover/lean4/pull/5109) add fine-grained equational lemmas for non-recursive functions. See breaking changes.
-  * [#5129](https://github.com/leanprover/lean4/pull/5129) unifies equation lemmas for recursive and non-recursive definitions. The `backward.eqns.deepRecursiveSplit` option can be set to `false` to get the old behavior. See breaking changes.
-  * [#5141](https://github.com/leanprover/lean4/pull/5141) adds `f.eq_unfold` lemmas. Now Lean produces the following zoo of rewrite rules:
-    ```
-    Option.map.eq_1      : Option.map f none = none
-    Option.map.eq_2      : Option.map f (some x) = some (f x)
-    Option.map.eq_def    : Option.map f p = match o with | none => none | (some x) => some (f x)
-    Option.map.eq_unfold : Option.map = fun f p => match o with | none => none | (some x) => some (f x)
-    ```
-    The `f.eq_unfold` variant is especially useful to rewrite with `rw` under binders.
-  * [#5136](https://github.com/leanprover/lean4/pull/5136) fixes bugs in recursion over predicates.
-
-* **Variable inclusion**
-  * [#5206](https://github.com/leanprover/lean4/pull/5206) documents that `include` currently only applies to theorems.
-
-* **Elaboration**
-  * [#4926](https://github.com/leanprover/lean4/pull/4926) fixes a bug where autoparam errors were associated to an incorrect source position.
-  * [#4833](https://github.com/leanprover/lean4/pull/4833) fixes an issue where cdot anonymous functions (e.g. `(· + ·)`) would not handle ambiguous notation correctly. Numbers the parameters, making this example expand as `fun x1 x2 => x1 + x2` rather than `fun x x_1 => x + x_1`.
-  * [#5037](https://github.com/leanprover/lean4/pull/5037) improves strength of the tactic that proves array indexing is in bounds.
-  * [#5119](https://github.com/leanprover/lean4/pull/5119) fixes a bug in the tactic that proves indexing is in bounds where it could loop in the presence of mvars.
-  * [#5072](https://github.com/leanprover/lean4/pull/5072) makes the structure type clickable in "not a field of structure" errors for structure instance notation.
-  * [#4717](https://github.com/leanprover/lean4/pull/4717) fixes a bug where mutual `inductive` commands could create terms that the kernel rejects.
-  * [#5142](https://github.com/leanprover/lean4/pull/5142) fixes a bug where `variable` could fail when mixing binder updates and declarations.
-
-* **Other fixes or improvements**
-  * [#5118](https://github.com/leanprover/lean4/pull/5118) changes the definition of the `syntheticHole` parser so that hovering over `_` in `?_` gives the docstring for synthetic holes.
-  * [#5173](https://github.com/leanprover/lean4/pull/5173) uses the emoji variant selector for ✅️,❌️,💥️ in messages, improving fonts selection.
-  * [#5183](https://github.com/leanprover/lean4/pull/5183) fixes a bug in `rename_i` where implementation detail hypotheses could be renamed.
-
-### Language server, widgets, and IDE extensions
-
-* [#4821](https://github.com/leanprover/lean4/pull/4821) resolves two language server bugs that especially affect Windows users. (1) Editing the header could result in the watchdog not correctly restarting the file worker, which would lead to the file seemingly being processed forever. (2) On an especially slow Windows machine, we found that starting the language server would sometimes not succeed at all. This PR also resolves an issue where we would not correctly emit messages that we received while the file worker is being restarted to the corresponding file worker after the restart.
-* [#5006](https://github.com/leanprover/lean4/pull/5006) updates the user widget manual.
-* [#5193](https://github.com/leanprover/lean4/pull/5193) updates the quickstart guide with the new display name for the Lean 4 extension ("Lean 4").
-* [#5185](https://github.com/leanprover/lean4/pull/5185) fixes a bug where over time "import out of date" messages would accumulate.
-* [#4900](https://github.com/leanprover/lean4/pull/4900) improves ilean loading performance by about a factor of two. Optimizes the JSON parser and the conversion from JSON to Lean data structures; see PR description for details.
-* **Other fixes or improvements**
-  * [#5031](https://github.com/leanprover/lean4/pull/5031) localizes an instance in `Lsp.Diagnostics`.
-
-### Pretty printing
-
-* [#4976](https://github.com/leanprover/lean4/pull/4976) introduces `@[app_delab]`, a macro for creating delaborators for particular constants. The `@[app_delab ident]` syntax resolves `ident` to its constant name `name` and then expands to `@[delab app.name]`.
-* [#4982](https://github.com/leanprover/lean4/pull/4982) fixes a bug where the pretty printer assumed structure projections were type correct (such terms can appear in type mismatch errors). Improves hoverability of `#print` output for structures.
-* [#5218](https://github.com/leanprover/lean4/pull/5218) and [#5239](https://github.com/leanprover/lean4/pull/5239) add `pp.exprSizes` debugging option. When true, each pretty printed expression is prefixed with `[size a/b/c]`, where `a` is the size without sharing, `b` is the actual size, and `c` is the size with the maximum possible sharing.
-
-### Library
-
-* [#5020](https://github.com/leanprover/lean4/pull/5020) swaps the parameters to `Membership.mem`. A purpose of this change is to make set-like `CoeSort` coercions to refer to the eta-expanded function `fun x => Membership.mem s x`, which can reduce in many computations. Another is that having the `s` argument first leads to better discrimination tree keys. (See breaking changes.)
-* `Array`
-  * [#4970](https://github.com/leanprover/lean4/pull/4970) adds `@[ext]` attribute to `Array.ext`.
-  * [#4957](https://github.com/leanprover/lean4/pull/4957) deprecates `Array.get_modify`.
-* `List`
-  * [#4995](https://github.com/leanprover/lean4/pull/4995) upstreams `List.findIdx` lemmas.
-  * [#5029](https://github.com/leanprover/lean4/pull/5029), [#5048](https://github.com/leanprover/lean4/pull/5048) and [#5132](https://github.com/leanprover/lean4/pull/5132) add `List.Sublist` lemmas, some upstreamed. [#5077](https://github.com/leanprover/lean4/pull/5077) fixes implicitness in refl/rfl lemma binders.  add `List.Sublist` theorems.
-  * [#5047](https://github.com/leanprover/lean4/pull/5047) upstreams `List.Pairwise` lemmas.
-  * [#5053](https://github.com/leanprover/lean4/pull/5053), [#5124](https://github.com/leanprover/lean4/pull/5124), and [#5161](https://github.com/leanprover/lean4/pull/5161) add `List.find?/findSome?/findIdx?` theorems.
-  * [#5039](https://github.com/leanprover/lean4/pull/5039) adds `List.foldlRecOn` and `List.foldrRecOn` recursion principles to prove things about `List.foldl` and `List.foldr`.
-  * [#5069](https://github.com/leanprover/lean4/pull/5069) upstreams `List.Perm`.
-  * [#5092](https://github.com/leanprover/lean4/pull/5092) and [#5107](https://github.com/leanprover/lean4/pull/5107) add `List.mergeSort` and a fast `@[csimp]` implementation.
-  * [#5103](https://github.com/leanprover/lean4/pull/5103) makes the simp lemmas for `List.subset` more aggressive.
-  * [#5106](https://github.com/leanprover/lean4/pull/5106) changes the statement of `List.getLast?_cons`.
-  * [#5123](https://github.com/leanprover/lean4/pull/5123) and [#5158](https://github.com/leanprover/lean4/pull/5158) add `List.range` and `List.iota` lemmas.
-  * [#5130](https://github.com/leanprover/lean4/pull/5130) adds `List.join` lemmas.
-  * [#5131](https://github.com/leanprover/lean4/pull/5131) adds `List.append` lemmas.
-  * [#5152](https://github.com/leanprover/lean4/pull/5152) adds `List.erase(|P|Idx)` lemmas.
-  * [#5127](https://github.com/leanprover/lean4/pull/5127) makes miscellaneous lemma updates.
-  * [#5153](https://github.com/leanprover/lean4/pull/5153) and [#5160](https://github.com/leanprover/lean4/pull/5160) add lemmas about `List.attach` and `List.pmap`.
-  * [#5164](https://github.com/leanprover/lean4/pull/5164), [#5177](https://github.com/leanprover/lean4/pull/5177), and [#5215](https://github.com/leanprover/lean4/pull/5215) add `List.find?` and `List.range'/range/iota` lemmas.
-  * [#5196](https://github.com/leanprover/lean4/pull/5196) adds `List.Pairwise_erase` and related lemmas.
-  * [#5151](https://github.com/leanprover/lean4/pull/5151) and [#5163](https://github.com/leanprover/lean4/pull/5163) improve confluence of `List` simp lemmas. [#5105](https://github.com/leanprover/lean4/pull/5105) and [#5102](https://github.com/leanprover/lean4/pull/5102) adjust `List` simp lemmas.
-  * [#5178](https://github.com/leanprover/lean4/pull/5178) removes `List.getLast_eq_iff_getLast_eq_some` as a simp lemma.
-  * [#5210](https://github.com/leanprover/lean4/pull/5210) reverses the meaning of `List.getElem_drop` and `List.getElem_drop'`.
-  * [#5214](https://github.com/leanprover/lean4/pull/5214) moves `@[csimp]` lemmas earlier where possible.
-* `Nat` and `Int`
-  * [#5104](https://github.com/leanprover/lean4/pull/5104) adds `Nat.add_left_eq_self` and relatives.
-  * [#5146](https://github.com/leanprover/lean4/pull/5146) adds missing `Nat.and_xor_distrib_(left|right)`.
-  * [#5148](https://github.com/leanprover/lean4/pull/5148) and [#5190](https://github.com/leanprover/lean4/pull/5190) improve `Nat` and `Int` simp lemma confluence.
-  * [#5165](https://github.com/leanprover/lean4/pull/5165) adjusts `Int` simp lemmas.
-  * [#5166](https://github.com/leanprover/lean4/pull/5166) adds `Int` lemmas relating `neg` and `emod`/`mod`.
-  * [#5208](https://github.com/leanprover/lean4/pull/5208) reverses the direction of the `Int.toNat_sub` simp lemma.
-  * [#5209](https://github.com/leanprover/lean4/pull/5209) adds `Nat.bitwise` lemmas.
-  * [#5230](https://github.com/leanprover/lean4/pull/5230) corrects the docstrings for integer division and modulus.
-* `Option`
-  * [#5128](https://github.com/leanprover/lean4/pull/5128) and [#5154](https://github.com/leanprover/lean4/pull/5154) add `Option` lemmas.
-* `BitVec`
-  * [#4889](https://github.com/leanprover/lean4/pull/4889) adds `sshiftRight` bitblasting.
-  * [#4981](https://github.com/leanprover/lean4/pull/4981) adds `Std.Associative` and `Std.Commutative` instances for `BitVec.[and|or|xor]`.
-  * [#4913](https://github.com/leanprover/lean4/pull/4913) enables `missingDocs` error for `BitVec` modules.
-  * [#4930](https://github.com/leanprover/lean4/pull/4930) makes parameter names for `BitVec` more consistent.
-  * [#5098](https://github.com/leanprover/lean4/pull/5098) adds `BitVec.intMin`. Introduces `boolToPropSimps` simp set for converting from boolean to propositional expressions.
-  * [#5200](https://github.com/leanprover/lean4/pull/5200) and [#5217](https://github.com/leanprover/lean4/pull/5217) rename `BitVec.getLsb` to `BitVec.getLsbD`, etc., to bring naming in line with `List`/`Array`/etc.
-  * **Theorems:** [#4977](https://github.com/leanprover/lean4/pull/4977), [#4951](https://github.com/leanprover/lean4/pull/4951), [#4667](https://github.com/leanprover/lean4/pull/4667), [#5007](https://github.com/leanprover/lean4/pull/5007), [#4997](https://github.com/leanprover/lean4/pull/4997), [#5083](https://github.com/leanprover/lean4/pull/5083), [#5081](https://github.com/leanprover/lean4/pull/5081), [#4392](https://github.com/leanprover/lean4/pull/4392)
-* `UInt`
-  * [#4514](https://github.com/leanprover/lean4/pull/4514) fixes naming convention for `UInt` lemmas.
-* `Std.HashMap` and `Std.HashSet`
-  * [#4943](https://github.com/leanprover/lean4/pull/4943) deprecates variants of hash map query methods. (See breaking changes.)
-  * [#4917](https://github.com/leanprover/lean4/pull/4917) switches the library and Lean to `Std.HashMap` and `Std.HashSet` almost everywhere.
-  * [#4954](https://github.com/leanprover/lean4/pull/4954) deprecates `Lean.HashMap` and `Lean.HashSet`.
-  * [#5023](https://github.com/leanprover/lean4/pull/5023) cleans up lemma parameters.
-
-* `Std.Sat` (for `bv_decide`)
-  * [#4933](https://github.com/leanprover/lean4/pull/4933) adds definitions of SAT and CNF.
-  * [#4953](https://github.com/leanprover/lean4/pull/4953) defines "and-inverter graphs" (AIGs) as described in section 3 of [Davis-Swords 2013](https://arxiv.org/pdf/1304.7861.pdf).
-
-* **Parsec**
-  * [#4774](https://github.com/leanprover/lean4/pull/4774) generalizes the `Parsec` library, allowing parsing of iterable data beyond `String` such as `ByteArray`. (See breaking changes.)
-  * [#5115](https://github.com/leanprover/lean4/pull/5115) moves `Lean.Data.Parsec` to `Std.Internal.Parsec` for bootstrappng reasons.
-
-* `Thunk`
-  * [#4969](https://github.com/leanprover/lean4/pull/4969) upstreams `Thunk.ext`.
-
-* **IO**
-  * [#4973](https://github.com/leanprover/lean4/pull/4973) modifies `IO.FS.lines` to handle `\r\n` on all operating systems instead of just on Windows.
-  * [#5125](https://github.com/leanprover/lean4/pull/5125) adds `createTempFile` and `withTempFile` for creating temporary files that can only be read and written by the current user.
-
-* **Other fixes or improvements**
-  * [#4945](https://github.com/leanprover/lean4/pull/4945) adds `Array`, `Bool` and `Prod` utilities from LeanSAT.
-  * [#4960](https://github.com/leanprover/lean4/pull/4960) adds `Relation.TransGen.trans`.
-  * [#5012](https://github.com/leanprover/lean4/pull/5012) states `WellFoundedRelation Nat` using `<`, not `Nat.lt`.
-  * [#5011](https://github.com/leanprover/lean4/pull/5011) uses `≠` instead of `Not (Eq ...)` in `Fin.ne_of_val_ne`.
-  * [#5197](https://github.com/leanprover/lean4/pull/5197) upstreams `Fin.le_antisymm`.
-  * [#5042](https://github.com/leanprover/lean4/pull/5042) reduces usage of `refine'`.
-  * [#5101](https://github.com/leanprover/lean4/pull/5101) adds about `if-then-else` and `Option`.
-  * [#5112](https://github.com/leanprover/lean4/pull/5112) adds basic instances for `ULift` and `PLift`.
-  * [#5133](https://github.com/leanprover/lean4/pull/5133) and [#5168](https://github.com/leanprover/lean4/pull/5168) make fixes from running the simpNF linter over Lean.
-  * [#5156](https://github.com/leanprover/lean4/pull/5156) removes a bad simp lemma in `omega` theory.
-  * [#5155](https://github.com/leanprover/lean4/pull/5155) improves confluence of `Bool` simp lemmas.
-  * [#5162](https://github.com/leanprover/lean4/pull/5162) improves confluence of `Function.comp` simp lemmas.
-  * [#5191](https://github.com/leanprover/lean4/pull/5191) improves confluence of `if-then-else` simp lemmas.
-  * [#5147](https://github.com/leanprover/lean4/pull/5147) adds `@[elab_as_elim]` to `Quot.rec`, `Nat.strongInductionOn` and `Nat.casesStrongInductionOn`, and also renames the latter two to `Nat.strongRecOn` and `Nat.casesStrongRecOn` (deprecated in [#5179](https://github.com/leanprover/lean4/pull/5179)).
-  * [#5180](https://github.com/leanprover/lean4/pull/5180) disables some simp lemmas with bad discrimination tree keys.
-  * [#5189](https://github.com/leanprover/lean4/pull/5189) cleans up internal simp lemmas that had leaked.
-  * [#5198](https://github.com/leanprover/lean4/pull/5198) cleans up `allowUnsafeReducibility`.
-  * [#5229](https://github.com/leanprover/lean4/pull/5229) removes unused lemmas from some `simp` tactics.
-  * [#5199](https://github.com/leanprover/lean4/pull/5199) removes >6 month deprecations.
-
-### Lean internals
-
-* **Performance**
-  * Some core algorithms have been rewritten in C++ for performance.
-    * [#4910](https://github.com/leanprover/lean4/pull/4910) and [#4912](https://github.com/leanprover/lean4/pull/4912) reimplement `instantiateLevelMVars`.
-    * [#4915](https://github.com/leanprover/lean4/pull/4915), [#4922](https://github.com/leanprover/lean4/pull/4922), and [#4931](https://github.com/leanprover/lean4/pull/4931) reimplement `instantiateExprMVars`, 30% faster on a benchmark.
-  * [#4934](https://github.com/leanprover/lean4/pull/4934) has optimizations for the kernel's `Expr` equality test.
-  * [#4990](https://github.com/leanprover/lean4/pull/4990) fixes bug in hashing for the kernel's `Expr` equality test.
-  * [#4935](https://github.com/leanprover/lean4/pull/4935) and [#4936](https://github.com/leanprover/lean4/pull/4936) skip some `PreDefinition` transformations if they are not needed.
-  * [#5225](https://github.com/leanprover/lean4/pull/5225) adds caching for visited exprs at `CheckAssignmentQuick` in `ExprDefEq`.
-  * [#5226](https://github.com/leanprover/lean4/pull/5226) maximizes term sharing at `instantiateMVarDeclMVars`, used by `runTactic`.
-* **Diagnostics and profiling**
-  * [#4923](https://github.com/leanprover/lean4/pull/4923) adds profiling for `instantiateMVars` in `Lean.Elab.MutualDef`, which can be a bottleneck there.
-  * [#4924](https://github.com/leanprover/lean4/pull/4924) adds diagnostics for large theorems, controlled by the `diagnostics.threshold.proofSize` option.
-  * [#4897](https://github.com/leanprover/lean4/pull/4897) improves display of diagnostic results.
-* **Other fixes or improvements**
-  * [#4921](https://github.com/leanprover/lean4/pull/4921) cleans up `Expr.betaRev`.
-  * [#4940](https://github.com/leanprover/lean4/pull/4940) fixes tests by not writing directly to stdout, which is unreliable now that elaboration and reporting are executed in separate threads.
-  * [#4955](https://github.com/leanprover/lean4/pull/4955) documents that `stderrAsMessages` is now the default on the command line as well.
-  * [#4647](https://github.com/leanprover/lean4/pull/4647) adjusts documentation for building on macOS.
-  * [#4987](https://github.com/leanprover/lean4/pull/4987) makes regular mvar assignments take precedence over delayed ones in `instantiateMVars`. Normally delayed assignment metavariables are never directly assigned, but on errors Lean assigns `sorry` to unassigned metavariables.
-  * [#4967](https://github.com/leanprover/lean4/pull/4967) adds linter name to errors when a linter crashes.
-  * [#5043](https://github.com/leanprover/lean4/pull/5043) cleans up command line snapshots logic.
-  * [#5067](https://github.com/leanprover/lean4/pull/5067) minimizes some imports.
-  * [#5068](https://github.com/leanprover/lean4/pull/5068) generalizes the monad for `addMatcherInfo`.
-  * [f71a1f](https://github.com/leanprover/lean4/commit/f71a1fb4ae958fccb3ad4d48786a8f47ced05c15) adds missing test for [#5126](https://github.com/leanprover/lean4/issues/5126).
-  * [#5201](https://github.com/leanprover/lean4/pull/5201) restores a test.
-  * [#3698](https://github.com/leanprover/lean4/pull/3698) fixes a bug where label attributes did not pass on the attribute kind.
-  * Typos: [#5080](https://github.com/leanprover/lean4/pull/5080), [#5150](https://github.com/leanprover/lean4/pull/5150), [#5202](https://github.com/leanprover/lean4/pull/5202)
-
-### Compiler, runtime, and FFI
-
-* [#3106](https://github.com/leanprover/lean4/pull/3106) moves frontend to new snapshot architecture. Note that `Frontend.processCommand` and `FrontendM` are no longer used by Lean core, but they will be preserved.
-* [#4919](https://github.com/leanprover/lean4/pull/4919) adds missing include in runtime for `AUTO_THREAD_FINALIZATION` feature on Windows.
-* [#4941](https://github.com/leanprover/lean4/pull/4941) adds more `LEAN_EXPORT`s for Windows.
-* [#4911](https://github.com/leanprover/lean4/pull/4911) improves formatting of CLI help text for the frontend.
-* [#4950](https://github.com/leanprover/lean4/pull/4950) improves file reading and writing.
-  * `readBinFile` and `readFile` now only require two system calls (`stat` + `read`) instead of one `read` per 1024 byte chunk.
-  * `Handle.getLine` and `Handle.putStr` no longer get tripped up by NUL characters.
-* [#4971](https://github.com/leanprover/lean4/pull/4971) handles the SIGBUS signal when detecting stack overflows.
-* [#5062](https://github.com/leanprover/lean4/pull/5062) avoids overwriting existing signal handlers, like in [rust-lang/rust#69685](https://github.com/rust-lang/rust/pull/69685).
-* [#4860](https://github.com/leanprover/lean4/pull/4860) improves workarounds for building on Windows. Splits `libleanshared` on Windows to avoid symbol limit, removes the `LEAN_EXPORT` denylist workaround, adds missing `LEAN_EXPORT`s.
-* [#4952](https://github.com/leanprover/lean4/pull/4952) output panics into Lean's redirected stderr, ensuring panics ARE visible as regular messages in the language server and properly ordered in relation to other messages on the command line.
-* [#4963](https://github.com/leanprover/lean4/pull/4963) links LibUV.
-
-### Lake
-
-* [#5030](https://github.com/leanprover/lean4/pull/5030) removes dead code.
-* [#4770](https://github.com/leanprover/lean4/pull/4770) adds additional fields to the package configuration which will be used by Reservoir. See the PR description for details.
-
-
-### DevOps/CI
-* [#4914](https://github.com/leanprover/lean4/pull/4914) and [#4937](https://github.com/leanprover/lean4/pull/4937) improve the release checklist.
-* [#4925](https://github.com/leanprover/lean4/pull/4925) ignores stale leanpkg tests.
-* [#5003](https://github.com/leanprover/lean4/pull/5003) upgrades `actions/cache` in CI.
-* [#5010](https://github.com/leanprover/lean4/pull/5010) sets `save-always` in cache actions in CI.
-* [#5008](https://github.com/leanprover/lean4/pull/5008) adds more libuv search patterns for the speedcenter.
-* [#5009](https://github.com/leanprover/lean4/pull/5009) reduce number of runs in the speedcenter for "fast" benchmarks from 10 to 3.
-* [#5014](https://github.com/leanprover/lean4/pull/5014) adjusts lakefile editing to use new `git` syntax in `pr-release` workflow.
-* [#5025](https://github.com/leanprover/lean4/pull/5025) has `pr-release` workflow pass `--retry` to `curl`.
-* [#5022](https://github.com/leanprover/lean4/pull/5022) builds MacOS Aarch64 release for PRs by default.
-* [#5045](https://github.com/leanprover/lean4/pull/5045) adds libuv to the required packages heading in macos docs.
-* [#5034](https://github.com/leanprover/lean4/pull/5034) fixes the install name of `libleanshared_1` on macOS.
-* [#5051](https://github.com/leanprover/lean4/pull/5051) fixes Windows stage 0.
-* [#5052](https://github.com/leanprover/lean4/pull/5052) fixes 32bit stage 0 builds in CI.
-* [#5057](https://github.com/leanprover/lean4/pull/5057) avoids rebuilding `leanmanifest` in each build.
-* [#5099](https://github.com/leanprover/lean4/pull/5099) makes `restart-on-label` workflow also filter by commit SHA.
-* [#4325](https://github.com/leanprover/lean4/pull/4325) adds CaDiCaL.
-
-### Breaking changes
-
-* [LibUV](https://libuv.org/) is now required to build Lean. This change only affects developers who compile Lean themselves instead of obtaining toolchains via `elan`. We have updated the official build instructions with information on how to obtain LibUV on our supported platforms. ([#4963](https://github.com/leanprover/lean4/pull/4963))
-
-* Recursive definitions with a `decreasing_by` clause that begins with `simp_wf` may break. Try removing `simp_wf` or replacing it with `simp`. ([#5016](https://github.com/leanprover/lean4/pull/5016))
-
-* The behavior of `rw [f]` where `f` is a non-recursive function defined by pattern matching changed.
-
-  For example, preciously, `rw [Option.map]` would rewrite `Option.map f o` to `match o with … `. Now this rewrite fails because it will use the equational lemmas, and these require constructors – just like for `List.map`.
-
-  Remedies:
-  * Split on `o` before rewriting.
-  * Use `rw [Option.map.eq_def]`, which rewrites any (saturated) application of `Option.map`.
-  * Use `set_option backward.eqns.nonrecursive false` when *defining* the function in question.
-  ([#4154](https://github.com/leanprover/lean4/pull/4154))
-
-* The unified handling of equation lemmas for recursive and non-recursive functions can break existing code, as there now can be extra equational lemmas:
-
-  * Explicit uses of `f.eq_2` might have to be adjusted if the numbering changed.
-
-  * Uses of `rw [f]` or `simp [f]` may no longer apply if they previously matched (and introduced a `match` statement), when the equational lemmas got more fine-grained.
-
-    In this case either case analysis on the parameters before rewriting helps, or setting the option `backward.eqns.deepRecursiveSplit false` while *defining* the function.
-
-  ([#5129](https://github.com/leanprover/lean4/pull/5129), [#5207](https://github.com/leanprover/lean4/pull/5207))
-
-* The `reduceCtorEq` simproc is now optional, and it might need to be included in lists of simp lemmas, like `simp only [reduceCtorEq]`. This simproc is responsible for reducing equalities of constructors. ([#5167](https://github.com/leanprover/lean4/pull/5167))
-
-* `Nat.strongInductionOn` is now `Nat.strongRecOn` and `Nat.caseStrongInductionOn` to `Nat.caseStrongRecOn`. ([#5147](https://github.com/leanprover/lean4/pull/5147))
-
-* The parameters to `Membership.mem` have been swapped, which affects all `Membership` instances. ([#5020](https://github.com/leanprover/lean4/pull/5020))
-
-* The meanings of `List.getElem_drop` and `List.getElem_drop'` have been reversed and the first is now a simp lemma. ([#5210](https://github.com/leanprover/lean4/pull/5210))
-
-* The `Parsec` library has moved from `Lean.Data.Parsec` to `Std.Internal.Parsec`. The `Parsec` type is now more general with a parameter for an iterable. Users parsing strings can migrate to `Parser` in the `Std.Internal.Parsec.String` namespace, which also includes string-focused parsing combinators. ([#4774](https://github.com/leanprover/lean4/pull/4774))
-
-* The `Lean` module has switched from `Lean.HashMap` and `Lean.HashSet` to `Std.HashMap` and `Std.HashSet` ([#4943](https://github.com/leanprover/lean4/pull/4943)). `Lean.HashMap` and `Lean.HashSet` are now deprecated ([#4954](https://github.com/leanprover/lean4/pull/4954)) and will be removed in a future release. Users of `Lean` APIs that interact with hash maps, for example `Lean.Environment.const2ModIdx`, might encounter minor breakage due to the following changes from `Lean.HashMap` to `Std.HashMap`:
-  * query functions use the term `get` instead of `find`, ([#4943](https://github.com/leanprover/lean4/pull/4943))
-  * the notation `map[key]` no longer returns an optional value but instead expects a proof that the key is present in the map. The previous behavior is available via the `map[key]?` notation.
-
+Development in progress.
 
 v4.11.0
 ----------
@@ -938,7 +21,7 @@ v4.11.0
 
   See breaking changes below.
 
-  PRs: [#4883](https://github.com/leanprover/lean4/pull/4883), [#4814](https://github.com/leanprover/lean4/pull/4814), [#5000](https://github.com/leanprover/lean4/pull/5000), [#5036](https://github.com/leanprover/lean4/pull/5036), [#5138](https://github.com/leanprover/lean4/pull/5138), [0edf1b](https://github.com/leanprover/lean4/commit/0edf1bac392f7e2fe0266b28b51c498306363a84).
+  PRs: [#4883](https://github.com/leanprover/lean4/pull/4883), [1242ff](https://github.com/leanprover/lean4/commit/1242ffbfb5a79296041683682268e770fc3cf820), [#5000](https://github.com/leanprover/lean4/pull/5000), [#5036](https://github.com/leanprover/lean4/pull/5036), [#5138](https://github.com/leanprover/lean4/pull/5138), [0edf1b](https://github.com/leanprover/lean4/commit/0edf1bac392f7e2fe0266b28b51c498306363a84).
 
 * **Recursive definitions**
   * Structural recursion can now be explicitly requested using

debug.log

@@ -0,0 +1 @@
+[0829/202002.254:ERROR:crashpad_client_win.cc(868)] not connected

doc/dev/bootstrap.md

@@ -103,21 +103,10 @@ your PR using rebase merge, bypassing the merge queue.
 As written above, changes in meta code in the current stage usually will only
 affect later stages. This is an issue in two specific cases.
 
-* For the special case of *quotations*, it is desirable to have changes in builtin parsers affect them immediately: when the changes in the parser become active in the next stage, builtin macros implemented via quotations should generate syntax trees compatible with the new parser, and quotation patterns in builtin macros and elaborators should be able to match syntax created by the new parser and macros.
-  Since quotations capture the syntax tree structure during execution of the current stage and turn it into code for the next stage, we need to run the current stage's builtin parsers in quotations via the interpreter for this to work.
-  Caveats:
-  * We activate this behavior by default when building stage 1 by setting `-Dinternal.parseQuotWithCurrentStage=true`.
-    We force-disable it inside `macro/macro_rules/elab/elab_rules` via `suppressInsideQuot` as they are guaranteed not to run in the next stage and may need to be run in the current one, so the stage 0 parser is the correct one to use for them.
-    It may be necessary to extend this disabling to functions that contain quotations and are (exclusively) used by one of the mentioned commands. A function using quotations should never be used by both builtin and non-builtin macros/elaborators. Example: https://github.com/leanprover/lean4/blob/f70b7e5722da6101572869d87832494e2f8534b7/src/Lean/Elab/Tactic/Config.lean#L118-L122
-  * The parser needs to be reachable via an `import` statement, otherwise the version of the previous stage will silently be used.
-  * Only the parser code (`Parser.fn`) is affected; all metadata such as leading tokens is taken from the previous stage.
-
-  For an example, see https://github.com/leanprover/lean4/commit/f9dcbbddc48ccab22c7674ba20c5f409823b4cc1#diff-371387aed38bb02bf7761084fd9460e4168ae16d1ffe5de041b47d3ad2d22422R13
-
 * For *non-builtin* meta code such as `notation`s or `macro`s in
   `Notation.lean`, we expect changes to affect the current file and all later
   files of the same stage immediately, just like outside the stdlib. To ensure
-  this, we build stage 1 using `-Dinterpreter.prefer_native=false` -
+  this, we need to build the stage using `-Dinterpreter.prefer_native=false` -
   otherwise, when executing a macro, the interpreter would notice that there is
   already a native symbol available for this function and run it instead of the
   new IR, but the symbol is from the previous stage!
@@ -135,11 +124,26 @@ affect later stages. This is an issue in two specific cases.
   further stages (e.g. after an `update-stage0`) will then need to be compiled
   with the flag set to `false` again since they will expect the new signature.
 
-  When enabling `prefer_native`, we usually want to *disable* `parseQuotWithCurrentStage` as it would otherwise make quotations use the interpreter after all.
-  However, there is a specific case where we want to set both options to `true`: when we make changes to a non-builtin parser like `simp` that has a builtin elaborator, we cannot have the new parser be active outside of quotations in stage 1 as the builtin elaborator from stage 0 would not understand them; on the other hand, we need quotations in e.g. the builtin `simp` elaborator to produce the new syntax in the next stage.
-  As this issue usually affects only tactics, enabling `debug.byAsSorry` instead of `prefer_native` can be a simpler solution.
+  For an example, see https://github.com/leanprover/lean4/commit/da4c46370d85add64ef7ca5e7cc4638b62823fbb.
 
-  For a `prefer_native` example, see https://github.com/leanprover/lean4/commit/da4c46370d85add64ef7ca5e7cc4638b62823fbb.
+* For the special case of *quotations*, it is desirable to have changes in
+  built-in parsers affect them immediately: when the changes in the parser
+  become active in the next stage, macros implemented via quotations should
+  generate syntax trees compatible with the new parser, and quotation patterns
+  in macro and elaborators should be able to match syntax created by the new
+  parser and macros. Since quotations capture the syntax tree structure during
+  execution of the current stage and turn it into code for the next stage, we
+  need to run the current stage's built-in parsers in quotation via the
+  interpreter for this to work. Caveats:
+  * Since interpreting full parsers is not nearly as cheap and we rarely change
+    built-in syntax, this needs to be opted in using `-Dinternal.parseQuotWithCurrentStage=true`.
+  * The parser needs to be reachable via an `import` statement, otherwise the
+    version of the previous stage will silently be used.
+  * Only the parser code (`Parser.fn`) is affected; all metadata such as leading
+    tokens is taken from the previous stage.
+
+  For an example, see https://github.com/leanprover/lean4/commit/f9dcbbddc48ccab22c7674ba20c5f409823b4cc1#diff-371387aed38bb02bf7761084fd9460e4168ae16d1ffe5de041b47d3ad2d22422
+  (from before the flag defaulted to `false`).
 
 To modify either of these flags both for building and editing the stdlib, adjust
 the code in `stage0/src/stdlib_flags.h`. The flags will automatically be reset

doc/examples/interp.lean

@@ -12,17 +12,17 @@ Remark: this example is based on an example found in the Idris manual.
 Vectors
 --------
 
-A `Vec` is a list of size `n` whose elements belong to a type `α`.
+A `Vector` is a list of size `n` whose elements belong to a type `α`.
 -/
 
-inductive Vec (α : Type u) : Nat → Type u
-  | nil : Vec α 0
-  | cons : α → Vec α n → Vec α (n+1)
+inductive Vector (α : Type u) : Nat → Type u
+  | nil : Vector α 0
+  | cons : α → Vector α n → Vector α (n+1)
 
 /-!
-We can overload the `List.cons` notation `::` and use it to create `Vec`s.
+We can overload the `List.cons` notation `::` and use it to create `Vector`s.
 -/
-infix:67 " :: " => Vec.cons
+infix:67 " :: " => Vector.cons
 
 /-!
 Now, we define the types of our simple functional language.
@@ -50,11 +50,11 @@ the builtin instance for `Add Int` as the solution.
 /-!
 Expressions are indexed by the types of the local variables, and the type of the expression itself.
 -/
-inductive HasType : Fin n → Vec Ty n → Ty → Type where
+inductive HasType : Fin n → Vector Ty n → Ty → Type where
   | stop : HasType 0 (ty :: ctx) ty
   | pop  : HasType k ctx ty → HasType k.succ (u :: ctx) ty
 
-inductive Expr : Vec Ty n → Ty → Type where
+inductive Expr : Vector Ty n → Ty → Type where
   | var   : HasType i ctx ty → Expr ctx ty
   | val   : Int → Expr ctx Ty.int
   | lam   : Expr (a :: ctx) ty → Expr ctx (Ty.fn a ty)
@@ -102,8 +102,8 @@ indexed over the types in scope. Since an environment is just another form of li
 to the vector of local variable types, we overload again the notation `::` so that we can use the usual list syntax.
 Given a proof that a variable is defined in the context, we can then produce a value from the environment.
 -/
-inductive Env : Vec Ty n → Type where
-  | nil  : Env Vec.nil
+inductive Env : Vector Ty n → Type where
+  | nil  : Env Vector.nil
   | cons : Ty.interp a → Env ctx → Env (a :: ctx)
 
 infix:67 " :: " => Env.cons

doc/examples/tc.lean

@@ -82,7 +82,9 @@ theorem Expr.typeCheck_correct (h₁ : HasType e ty) (h₂ : e.typeCheck ≠ .un
 /-!
 Now, we prove that if `Expr.typeCheck e` returns `Maybe.unknown`, then forall `ty`, `HasType e ty` does not hold.
 The notation `e.typeCheck` is sugar for `Expr.typeCheck e`. Lean can infer this because we explicitly said that `e` has type `Expr`.
-The proof is by induction on `e` and case analysis. Note that the tactic `simp [typeCheck]` is applied to all goal generated by the `induction` tactic, and closes
+The proof is by induction on `e` and case analysis. The tactic `rename_i` is used to rename "inaccessible" variables.
+We say a variable is inaccessible if it is introduced by a tactic (e.g., `cases`) or has been shadowed by another variable introduced
+by the user. Note that the tactic `simp [typeCheck]` is applied to all goal generated by the `induction` tactic, and closes
 the cases corresponding to the constructors `Expr.nat` and `Expr.bool`.
 -/
 theorem Expr.typeCheck_complete {e : Expr} : e.typeCheck = .unknown → ¬ HasType e ty := by

doc/examples/test_single.sh

@@ -1,4 +1,4 @@
 #!/usr/bin/env bash
 source ../../tests/common.sh
 
-exec_check_raw lean -Dlinter.all=false "$f"
+exec_check lean -Dlinter.all=false "$f"

doc/lexical_structure.md

@@ -128,16 +128,16 @@ Numeric literals can be specified in various bases.
 
 ```
    numeral    : numeral10 | numeral2 | numeral8 | numeral16
-   numeral10  : [0-9]+ ("_"+ [0-9]+)*
-   numeral2   : "0" [bB] ("_"* [0-1]+)+
-   numeral8   : "0" [oO] ("_"* [0-7]+)+
-   numeral16  : "0" [xX] ("_"* hex_char+)+
+   numeral10  : [0-9]+
+   numeral2   : "0" [bB] [0-1]+
+   numeral8   : "0" [oO] [0-7]+
+   numeral16  : "0" [xX] hex_char+
 ```
 
 Floating point literals are also possible with optional exponent:
 
 ```
-   float    : numeral10 "." numeral10? [eE[+-]numeral10]
+   float    : [0-9]+ "." [0-9]+ [[eE[+-][0-9]+]
 ```
 
 For example:
@@ -147,7 +147,6 @@ constant w : Int := 55
 constant x : Nat := 26085
 constant y : Nat := 0x65E5
 constant z : Float := 2.548123e-05
-constant b : Bool := 0b_11_01_10_00
 ```
 
 Note: that negative numbers are created by applying the "-" negation prefix operator to the number, for example:

doc/make/index.md

@@ -1,6 +1,6 @@
-These are instructions to set up a working development environment for those who wish to make changes to Lean itself. It is part of the [Development Guide](../dev/index.md).
+These are instructions to set up a working development environment for those who wish to make changes to Lean itself. It is part of the [Development Guide](doc/dev/index.md).
 
-We strongly suggest that new users instead follow the [Quickstart](../quickstart.md) to get started using Lean, since this sets up an environment that can automatically manage multiple Lean toolchain versions, which is necessary when working within the Lean ecosystem.
+We strongly suggest that new users instead follow the [Quickstart](doc/quickstart.md) to get started using Lean, since this sets up an environment that can automatically manage multiple Lean toolchain versions, which is necessary when working within the Lean ecosystem.
 
 Requirements
 ------------

doc/make/msys2.md

@@ -15,24 +15,17 @@ Mode](https://docs.microsoft.com/en-us/windows/apps/get-started/enable-your-devi
 which will allow Lean to create symlinks that e.g. enable go-to-definition in
 the stdlib.
 
-## Installing the Windows SDK
-
-Install the Windows SDK from [Microsoft](https://developer.microsoft.com/en-us/windows/downloads/windows-sdk/).
-The oldest supported version is 10.0.18362.0. If you installed the Windows SDK to the default location,
-then there should be a directory with the version number at `C:\Program Files (x86)\Windows Kits\10\Include`.
-If there are multiple directories, only the highest version number matters.
-
 ## Installing dependencies
 
 [The official webpage of MSYS2][msys2] provides one-click installers.
-Once installed, you should run the "MSYS2 CLANG64" shell from the start menu (the one that runs `clang64.exe`).
-Do not run "MSYS2 MSYS" or "MSYS2 MINGW64" instead!
-MSYS2 has a package management system, [pacman][pacman].
+Once installed, you should run the "MSYS2 MinGW 64-bit shell" from the start menu (the one that runs `mingw64.exe`).
+Do not run "MSYS2 MSYS" instead!
+MSYS2 has a package management system, [pacman][pacman], which is used in Arch Linux.
 
 Here are the commands to install all dependencies needed to compile Lean on your machine.
 
 ```bash
-pacman -S make python mingw-w64-clang-x86_64-cmake mingw-w64-clang-x86_64-clang mingw-w64-clang-x86_64-ccache mingw-w64-clang-x86_64-libuv mingw-w64-clang-x86_64-gmp git unzip diffutils binutils
+pacman -S make python mingw-w64-x86_64-cmake mingw-w64-x86_64-clang mingw-w64-x86_64-ccache mingw-w64-x86_64-libuv mingw-w64-x86_64-gmp git unzip diffutils binutils
 ```
 
 You should now be able to run these commands:
@@ -68,7 +61,8 @@ If you want a version that can run independently of your MSYS install
 then you need to copy the following dependent DLL's from where ever
 they are installed in your MSYS setup:
 
-- libc++.dll
+- libgcc_s_seh-1.dll
+- libstdc++-6.dll
 - libgmp-10.dll
 - libuv-1.dll
 - libwinpthread-1.dll
@@ -88,6 +82,6 @@ version clang to your path.
 
 **-bash: gcc: command not found**
 
-Make sure `/clang64/bin` is in your PATH environment.  If it is not then
-check you launched the MSYS2 CLANG64 shell from the start menu.
-(The one that runs `clang64.exe`).
+Make sure `/mingw64/bin` is in your PATH environment.  If it is not then
+check you launched the MSYS2 MinGW 64-bit shell from the start menu.
+(The one that runs `mingw64.exe`).

doc/monads/applicatives.lean

@@ -138,8 +138,8 @@ definition:
 
 -/
 instance : Applicative List where
-  pure := List.singleton
-  seq f x := List.flatMap f fun y => Functor.map y (x ())
+  pure := List.pure
+  seq f x := List.bind f fun y => Functor.map y (x ())
 /-!
 
 Notice you can now sequence a _list_ of functions and a _list_ of items.

doc/monads/laws.lean

@@ -128,8 +128,8 @@ Applying the identity function through an applicative structure should not chang
 values or structure.  For example:
 -/
 instance : Applicative List where
-  pure := List.singleton
-  seq f x := List.flatMap f fun y => Functor.map y (x ())
+  pure := List.pure
+  seq f x := List.bind f fun y => Functor.map y (x ())
 
 #eval pure id <*> [1, 2, 3]  -- [1, 2, 3]
 /-!
@@ -235,8 +235,8 @@ structure or its values.
 Left identity is `x >>= pure = x` and is demonstrated by the following examples on a monadic `List`:
 -/
 instance : Monad List  where
-  pure := List.singleton
-  bind := List.flatMap
+  pure := List.pure
+  bind := List.bind
 
 def a := ["apple", "orange"]
 

doc/monads/monads.lean

@@ -192,8 +192,8 @@ implementation of `pure` and `bind`.
 
 -/
 instance : Monad List  where
-  pure := List.singleton
-  bind := List.flatMap
+  pure := List.pure
+  bind := List.bind
 /-!
 
 Like you saw with the applicative `seq` operator, the `bind` operator applies the given function

doc/monads/readers.lean

@@ -139,7 +139,7 @@ You might be wondering, how does the context actually move through the `ReaderM`
 add an input argument to a function by modifying its return type?  There is a special command in
 Lean that will show you the reduced types:
 -/
-#reduce (types := true) ReaderM Environment String   -- Environment → String
+#reduce ReaderM Environment String   -- Environment → String
 /-!
 And you can see here that this type is actually a function!  It's a function that takes an
 `Environment` as input and returns a `String`.
@@ -196,4 +196,4 @@ entirely.
 
 Now it's time to move on to [StateM Monad](states.lean.md) which is like a `ReaderM` that is
 also updatable.
--/
+-/

doc/setup.md

@@ -7,7 +7,7 @@ Platforms built & tested by our CI, available as binary releases via elan (see b
 * x86-64 Linux with glibc 2.27+
 * x86-64 macOS 10.15+
 * aarch64 (Apple Silicon) macOS 10.15+
-* x86-64 Windows 11 (any version), Windows 10 (version 1903 or higher), Windows Server 2022
+* x86-64 Windows 10+
 
 ### Tier 2
 

flake.nix

@@ -38,24 +38,8 @@
           # more convenient `ctest` output
           CTEST_OUTPUT_ON_FAILURE = 1;
         } // pkgs.lib.optionalAttrs pkgs.stdenv.isLinux {
-          GMP = (pkgsDist.gmp.override { withStatic = true; }).overrideAttrs (attrs:
-            pkgs.lib.optionalAttrs (pkgs.stdenv.system == "aarch64-linux") {
-              # would need additional linking setup on Linux aarch64, we don't use it anywhere else either
-              hardeningDisable = [ "stackprotector" ];
-            });
-          LIBUV = pkgsDist.libuv.overrideAttrs (attrs: {
-            configureFlags = ["--enable-static"];
-            hardeningDisable = [ "stackprotector" ];
-            # Sync version with CMakeLists.txt
-            version = "1.48.0";
-            src = pkgs.fetchFromGitHub {
-              owner = "libuv";
-              repo = "libuv";
-              rev = "v1.48.0";
-              sha256 = "100nj16fg8922qg4m2hdjh62zv4p32wyrllsvqr659hdhjc03bsk";
-            };
-            doCheck = false;
-          });
+          GMP = pkgsDist.gmp.override { withStatic = true; };
+          LIBUV = pkgsDist.libuv.overrideAttrs (attrs: { configureFlags = ["--enable-static"]; });
           GLIBC = pkgsDist.glibc;
           GLIBC_DEV = pkgsDist.glibc.dev;
           GCC_LIB = pkgsDist.gcc.cc.lib;

nix/bootstrap.nix

@@ -170,7 +170,7 @@ lib.warn "The Nix-based build is deprecated" rec {
           ln -sf ${lean-all}/* .
         '';
         buildPhase = ''
-         ctest --output-junit test-results.xml --output-on-failure -E 'leancomptest_(doc_example|foreign)|leanlaketest_reverse-ffi|leanruntest_timeIO' -j$NIX_BUILD_CORES
+          ctest --output-junit test-results.xml --output-on-failure -E 'leancomptest_(doc_example|foreign)|leanlaketest_reverse-ffi' -j$NIX_BUILD_CORES
         '';
         installPhase = ''
           mkdir $out

releases_drafts/hashmap.md

@@ -0,0 +1,3 @@
+* The `Lean` module has switched from `Lean.HashMap` and `Lean.HashSet` to `Std.HashMap` and `Std.HashSet`. `Lean.HashMap` and `Lean.HashSet` are now deprecated and will be removed in a future release. Users of `Lean` APIs that interact with hash maps, for example `Lean.Environment.const2ModIdx`, might encounter minor breakage due to the following breaking changes from `Lean.HashMap` to `Std.HashMap`:
+    * query functions use the term `get` instead of `find`,
+    * the notation `map[key]` no longer returns an optional value but expects a proof that the key is present in the map instead. The previous behavior is available via the `map[key]?` notation.

releases_drafts/libuv.md

@@ -0,0 +1 @@
+* #4963 [LibUV](https://libuv.org/) is now required to build Lean. This change only affects developers who compile Lean themselves instead of obtaining toolchains via `elan`. We have updated the official build instructions with information on how to obtain LibUV on our supported platforms.

script/mathlib-bench

@@ -1,12 +0,0 @@
-#! /bin/env bash
-# Open a Mathlib4 PR for benchmarking a given Lean 4 PR
-
-set -euo pipefail
-
-[ $# -eq 1 ] || (echo "usage: $0 <lean4 PR #>"; exit 1)
-
-LEAN_PR=$1
-PR_RESPONSE=$(gh api repos/leanprover-community/mathlib4/pulls -X POST -f head=lean-pr-testing-$LEAN_PR -f base=nightly-testing -f title="leanprover/lean4#$LEAN_PR benchmarking" -f draft=true -f body="ignore me")
-PR_NUMBER=$(echo "$PR_RESPONSE" | jq '.number')
-echo "opened https://github.com/leanprover-community/mathlib4/pull/$PR_NUMBER"
-gh api repos/leanprover-community/mathlib4/issues/$PR_NUMBER/comments -X POST -f body="!bench" > /dev/null

script/prepare-llvm-linux.sh

@@ -48,8 +48,6 @@ $CP llvm-host/lib/*/lib{c++,c++abi,unwind}.* llvm-host/lib/
 $CP -r llvm/include/*-*-* llvm-host/include/
 # glibc: use for linking (so Lean programs don't embed newer symbol versions), but not for running (because libc.so, librt.so, and ld.so must be compatible)!
 $CP $GLIBC/lib/libc_nonshared.a stage1/lib/glibc
-# libpthread_nonshared.a must be linked in order to be able to use `pthread_atfork(3)`. LibUV uses this function.
-$CP $GLIBC/lib/libpthread_nonshared.a stage1/lib/glibc
 for f in $GLIBC/lib/lib{c,dl,m,rt,pthread}-*; do b=$(basename $f); cp $f stage1/lib/glibc/${b%-*}.so; done
 OPTIONS=()
 echo -n " -DLEAN_STANDALONE=ON"
@@ -64,8 +62,8 @@ fi
 # use `-nostdinc` to make sure headers are not visible by default (in particular, not to `#include_next` in the clang headers),
 # but do not change sysroot so users can still link against system libs
 echo -n " -DLEANC_INTERNAL_FLAGS='-nostdinc -isystem ROOT/include/clang' -DLEANC_CC=ROOT/bin/clang"
-echo -n " -DLEANC_INTERNAL_LINKER_FLAGS='-L ROOT/lib -L ROOT/lib/glibc ROOT/lib/glibc/libc_nonshared.a ROOT/lib/glibc/libpthread_nonshared.a -Wl,--as-needed -Wl,-Bstatic -lgmp -lunwind -luv -Wl,-Bdynamic -Wl,--no-as-needed -fuse-ld=lld'"
+echo -n " -DLEANC_INTERNAL_LINKER_FLAGS='-L ROOT/lib -L ROOT/lib/glibc ROOT/lib/glibc/libc_nonshared.a -Wl,--as-needed -Wl,-Bstatic -lgmp -lunwind -luv -Wl,-Bdynamic -Wl,--no-as-needed -fuse-ld=lld'"
 # when not using the above flags, link GMP dynamically/as usual
-echo -n " -DLEAN_EXTRA_LINKER_FLAGS='-Wl,--as-needed -lgmp -luv -lpthread -ldl -lrt -Wl,--no-as-needed'"
+echo -n " -DLEAN_EXTRA_LINKER_FLAGS='-Wl,--as-needed -lgmp -luv -Wl,--no-as-needed'"
 # do not set `LEAN_CC` for tests
 echo -n " -DLEAN_TEST_VARS=''"

script/prepare-llvm-mingw.sh

@@ -31,21 +31,15 @@ cp /clang64/lib/{crtbegin,crtend,crt2,dllcrt2}.o stage1/lib/
 # runtime
 (cd llvm; cp --parents lib/clang/*/lib/*/libclang_rt.builtins* ../stage1)
 # further dependencies
-# Note: even though we're linking against libraries like `libbcrypt.a` which appear to be static libraries from the file name,
-# we're not actually linking statically against the code.
-# Rather, `libbcrypt.a` is an import library (see https://en.wikipedia.org/wiki/Dynamic-link_library#Import_libraries) that just
-# tells the compiler how to dynamically link against `bcrypt.dll` (which is located in the System32 folder).
-# This distinction is relevant specifically for `libicu.a`/`icu.dll` because there we want updates to the time zone database to
-# be delivered to users via Windows Update without having to recompile Lean or Lean programs.
-cp /clang64/lib/lib{m,bcrypt,mingw32,moldname,mingwex,msvcrt,pthread,advapi32,shell32,user32,kernel32,ucrtbase,psapi,iphlpapi,userenv,ws2_32,dbghelp,ole32,icu}.* /clang64/lib/libgmp.a /clang64/lib/libuv.a llvm/lib/lib{c++,c++abi,unwind}.a stage1/lib/
+cp /clang64/lib/lib{m,bcrypt,mingw32,moldname,mingwex,msvcrt,pthread,advapi32,shell32,user32,kernel32,ucrtbase}.* /clang64/lib/libgmp.a /clang64/lib/libuv.a llvm/lib/lib{c++,c++abi,unwind}.a stage1/lib/
 echo -n " -DLEAN_STANDALONE=ON"
 echo -n " -DCMAKE_C_COMPILER=$PWD/stage1/bin/clang.exe -DCMAKE_C_COMPILER_WORKS=1 -DCMAKE_CXX_COMPILER=$PWD/llvm/bin/clang++.exe -DCMAKE_CXX_COMPILER_WORKS=1 -DLEAN_CXX_STDLIB='-lc++ -lc++abi'"
 echo -n " -DSTAGE0_CMAKE_C_COMPILER=clang -DSTAGE0_CMAKE_CXX_COMPILER=clang++"
 echo -n " -DLEAN_EXTRA_CXX_FLAGS='--sysroot $PWD/llvm -idirafter /clang64/include/'"
 echo -n " -DLEANC_INTERNAL_FLAGS='--sysroot ROOT -nostdinc -isystem ROOT/include/clang' -DLEANC_CC=ROOT/bin/clang.exe"
-echo -n " -DLEANC_INTERNAL_LINKER_FLAGS='-L ROOT/lib -static-libgcc -Wl,-Bstatic -lgmp $(pkg-config --static --libs libuv) -lunwind -Wl,-Bdynamic -fuse-ld=lld'"
-# when not using the above flags, link GMP dynamically/as usual. Always link ICU dynamically.
-echo -n " -DLEAN_EXTRA_LINKER_FLAGS='-lgmp $(pkg-config --libs libuv) -lucrtbase'"
+echo -n " -DLEANC_INTERNAL_LINKER_FLAGS='-L ROOT/lib -static-libgcc -Wl,-Bstatic -lgmp -luv -lunwind -Wl,-Bdynamic -fuse-ld=lld'"
+# when not using the above flags, link GMP dynamically/as usual
+echo -n " -DLEAN_EXTRA_LINKER_FLAGS='-lgmp -luv -lucrtbase'"
 # do not set `LEAN_CC` for tests
 echo -n " -DAUTO_THREAD_FINALIZATION=OFF -DSTAGE0_AUTO_THREAD_FINALIZATION=OFF"
 echo -n " -DLEAN_TEST_VARS=''"

src/CMakeLists.txt

@@ -10,15 +10,13 @@ endif()
 include(ExternalProject)
 project(LEAN CXX C)
 set(LEAN_VERSION_MAJOR 4)
-set(LEAN_VERSION_MINOR 16)
+set(LEAN_VERSION_MINOR 12)
 set(LEAN_VERSION_PATCH 0)
 set(LEAN_VERSION_IS_RELEASE 0)  # This number is 1 in the release revision, and 0 otherwise.
 set(LEAN_SPECIAL_VERSION_DESC "" CACHE STRING "Additional version description like 'nightly-2018-03-11'")
 set(LEAN_VERSION_STRING "${LEAN_VERSION_MAJOR}.${LEAN_VERSION_MINOR}.${LEAN_VERSION_PATCH}")
 if (LEAN_SPECIAL_VERSION_DESC)
   string(APPEND LEAN_VERSION_STRING "-${LEAN_SPECIAL_VERSION_DESC}")
-elseif (NOT LEAN_VERSION_IS_RELEASE)
-  string(APPEND LEAN_VERSION_STRING "-pre")
 endif()
 
 set(LEAN_PLATFORM_TARGET "" CACHE STRING "LLVM triple of the target platform")
@@ -51,8 +49,6 @@ option(LLVM               "LLVM"               OFF)
 option(USE_GITHASH        "GIT_HASH"           ON)
 # When ON we install LICENSE files to CMAKE_INSTALL_PREFIX
 option(INSTALL_LICENSE "INSTALL_LICENSE" ON)
-# When ON we install a copy of cadical
-option(INSTALL_CADICAL "Install a copy of cadical" ON)
 # When ON thread storage is automatically finalized, it assumes platform support pthreads.
 # This option is important when using Lean as library that is invoked from a different programming language (e.g., Haskell).
 option(AUTO_THREAD_FINALIZATION "AUTO_THREAD_FINALIZATION" ON)
@@ -122,7 +118,7 @@ if(${CMAKE_SYSTEM_NAME} MATCHES "Emscripten")
     # From https://emscripten.org/docs/compiling/WebAssembly.html#backends:
     # > The simple and safe thing is to pass all -s flags at both compile and link time.
     set(EMSCRIPTEN_SETTINGS "-s ALLOW_MEMORY_GROWTH=1 -fwasm-exceptions -pthread -flto")
-    string(APPEND LEANC_EXTRA_CC_FLAGS " -pthread")
+    string(APPEND LEANC_EXTRA_FLAGS " -pthread")
     string(APPEND LEAN_EXTRA_CXX_FLAGS " -D LEAN_EMSCRIPTEN ${EMSCRIPTEN_SETTINGS}")
     string(APPEND LEAN_EXTRA_LINKER_FLAGS " ${EMSCRIPTEN_SETTINGS}")
 endif()
@@ -157,11 +153,7 @@ if ((${MULTI_THREAD} MATCHES "ON") AND (${CMAKE_SYSTEM_NAME} MATCHES "Darwin"))
 endif ()
 
 # We want explicit stack probes in huge Lean stack frames for robust stack overflow detection
-string(APPEND LEANC_EXTRA_CC_FLAGS " -fstack-clash-protection")
-
-# This makes signed integer overflow guaranteed to match 2's complement.
-string(APPEND CMAKE_CXX_FLAGS " -fwrapv")
-string(APPEND LEANC_EXTRA_CC_FLAGS " -fwrapv")
+string(APPEND LEANC_EXTRA_FLAGS " -fstack-clash-protection")
 
 if(NOT MULTI_THREAD)
   message(STATUS "Disabled multi-thread support, it will not be safe to run multiple threads in parallel")
@@ -251,77 +243,15 @@ if("${USE_GMP}" MATCHES "ON")
   endif()
 endif()
 
-# LibUV
-if("${CMAKE_SYSTEM_NAME}" MATCHES "Emscripten")
-  # Only on WebAssembly we compile LibUV ourselves
-  set(LIBUV_EMSCRIPTEN_FLAGS "${EMSCRIPTEN_SETTINGS}")
-
-  # LibUV does not compile on WebAssembly without modifications because
-  # building LibUV on a platform requires including stub implementations
-  # for features not present on the target platform. This patch includes
-  # the minimum amount of stub implementations needed for successfully
-  # running Lean on WebAssembly and using LibUV's temporary file support.
-  # It still leaves several symbols completely undefined: uv__fs_event_close,
-  # uv__hrtime, uv__io_check_fd, uv__io_fork, uv__io_poll, uv__platform_invalidate_fd
-  # uv__platform_loop_delete, uv__platform_loop_init. Making additional
-  # LibUV features available on WebAssembly might require adapting the
-  # patch to include additional LibUV source files.
-  set(LIBUV_PATCH_IN "
-diff --git a/CMakeLists.txt b/CMakeLists.txt
-index 5e8e0166..f3b29134 100644
---- a/CMakeLists.txt
-+++ b/CMakeLists.txt
-@@ -317,6 +317,11 @@ if(CMAKE_SYSTEM_NAME STREQUAL \"GNU\")
-        src/unix/hurd.c)
- endif()
-
-+if(CMAKE_SYSTEM_NAME STREQUAL \"Emscripten\")
-+  list(APPEND uv_sources
-+       src/unix/no-proctitle.c)
-+endif()
-+
- if(CMAKE_SYSTEM_NAME STREQUAL \"Linux\")
-   list(APPEND uv_defines _GNU_SOURCE _POSIX_C_SOURCE=200112)
-   list(APPEND uv_libraries dl rt)
-")
-  string(REPLACE "\n" "\\n" LIBUV_PATCH ${LIBUV_PATCH_IN})
-
-  ExternalProject_add(libuv
-    PREFIX libuv
-    GIT_REPOSITORY https://github.com/libuv/libuv
-    # Sync version with flake.nix
-    GIT_TAG v1.48.0
-    CMAKE_ARGS -DCMAKE_BUILD_TYPE=Release -DLIBUV_BUILD_TESTS=OFF -DLIBUV_BUILD_SHARED=OFF -DCMAKE_AR=${CMAKE_AR} -DCMAKE_TOOLCHAIN_FILE=${CMAKE_TOOLCHAIN_FILE} -DCMAKE_POSITION_INDEPENDENT_CODE=ON -DCMAKE_C_FLAGS=${LIBUV_EMSCRIPTEN_FLAGS}
-	  PATCH_COMMAND git reset --hard HEAD && printf "${LIBUV_PATCH}" > patch.diff && git apply patch.diff
-    BUILD_IN_SOURCE ON
-    INSTALL_COMMAND "")
-  set(LIBUV_INCLUDE_DIR "${CMAKE_BINARY_DIR}/libuv/src/libuv/include")
-  set(LIBUV_LIBRARIES "${CMAKE_BINARY_DIR}/libuv/src/libuv/libuv.a")
-else()
+if(NOT "${CMAKE_SYSTEM_NAME}" MATCHES "Emscripten")
+  # LibUV
   find_package(LibUV 1.0.0 REQUIRED)
+  include_directories(${LIBUV_INCLUDE_DIR})
 endif()
-include_directories(${LIBUV_INCLUDE_DIR})
 if(NOT LEAN_STANDALONE)
   string(APPEND LEAN_EXTRA_LINKER_FLAGS " ${LIBUV_LIBRARIES}")
 endif()
 
-# Windows SDK (for ICU)
-if(${CMAKE_SYSTEM_NAME} MATCHES "Windows")
-  # Pass 'tools' to skip MSVC version check (as MSVC/Visual Studio is not necessarily installed)
-  find_package(WindowsSDK REQUIRED COMPONENTS tools)
-
-  # This will give a semicolon-separated list of include directories
-  get_windowssdk_include_dirs(${WINDOWSSDK_LATEST_DIR} WINDOWSSDK_INCLUDE_DIRS)
-
-  # To successfully build against Windows SDK headers, the Windows SDK headers must have lower
-  # priority than other system headers, so use `-idirafter`. Unfortunately, CMake does not
-  # support this using `include_directories`.
-  string(REPLACE ";" "\" -idirafter \"" WINDOWSSDK_INCLUDE_DIRS "${WINDOWSSDK_INCLUDE_DIRS}")
-  string(APPEND CMAKE_CXX_FLAGS " -idirafter \"${WINDOWSSDK_INCLUDE_DIRS}\"")
-
-  string(APPEND LEAN_EXTRA_LINKER_FLAGS " -licu")
-endif()
-
 # ccache
 if(CCACHE AND NOT CMAKE_CXX_COMPILER_LAUNCHER AND NOT CMAKE_C_COMPILER_LAUNCHER)
   find_program(CCACHE_PATH ccache)
@@ -451,7 +381,7 @@ if(${CMAKE_SYSTEM_NAME} MATCHES "Linux")
     string(APPEND TOOLCHAIN_SHARED_LINKER_FLAGS " -Wl,-Bsymbolic")
   endif()
   string(APPEND CMAKE_CXX_FLAGS " -fPIC -ftls-model=initial-exec")
-  string(APPEND LEANC_EXTRA_CC_FLAGS " -fPIC")
+  string(APPEND LEANC_EXTRA_FLAGS " -fPIC")
   string(APPEND TOOLCHAIN_SHARED_LINKER_FLAGS " -Wl,-rpath=\\$$ORIGIN/..:\\$$ORIGIN")
   string(APPEND LAKESHARED_LINKER_FLAGS " -Wl,--whole-archive ${CMAKE_BINARY_DIR}/lib/temp/libLake.a.export -Wl,--no-whole-archive")
   string(APPEND CMAKE_EXE_LINKER_FLAGS " -Wl,-rpath=\\\$ORIGIN/../lib:\\\$ORIGIN/../lib/lean")
@@ -464,7 +394,7 @@ elseif(${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
   string(APPEND CMAKE_EXE_LINKER_FLAGS " -Wl,-rpath,@executable_path/../lib -Wl,-rpath,@executable_path/../lib/lean")
 elseif(${CMAKE_SYSTEM_NAME} MATCHES "Emscripten")
   string(APPEND CMAKE_CXX_FLAGS " -fPIC")
-  string(APPEND LEANC_EXTRA_CC_FLAGS " -fPIC")
+  string(APPEND LEANC_EXTRA_FLAGS " -fPIC")
 elseif(${CMAKE_SYSTEM_NAME} MATCHES "Windows")
   string(APPEND LAKESHARED_LINKER_FLAGS " -Wl,--out-implib,${CMAKE_BINARY_DIR}/lib/lean/libLake_shared.dll.a -Wl,--whole-archive ${CMAKE_BINARY_DIR}/lib/temp/libLake.a.export -Wl,--no-whole-archive")
 endif()
@@ -479,7 +409,7 @@ if(NOT(${CMAKE_SYSTEM_NAME} MATCHES "Windows") AND NOT(${CMAKE_SYSTEM_NAME} MATC
   string(APPEND CMAKE_EXE_LINKER_FLAGS " -rdynamic")
   # hide all other symbols
   string(APPEND CMAKE_CXX_FLAGS " -fvisibility=hidden -fvisibility-inlines-hidden")
-  string(APPEND LEANC_EXTRA_CC_FLAGS " -fvisibility=hidden")
+  string(APPEND LEANC_EXTRA_FLAGS " -fvisibility=hidden")
 endif()
 
 # On Windows, add bcrypt for random number generation
@@ -505,7 +435,7 @@ endif()
 # Git HASH
 if(USE_GITHASH)
   include(GetGitRevisionDescription)
-  get_git_head_revision(GIT_REFSPEC GIT_SHA1 ALLOW_LOOKING_ABOVE_CMAKE_SOURCE_DIR)
+  get_git_head_revision(GIT_REFSPEC GIT_SHA1)
   if(${GIT_SHA1} MATCHES "GITDIR-NOTFOUND")
     message(STATUS "Failed to read git_sha1")
     set(GIT_SHA1 "")
@@ -544,10 +474,9 @@ include_directories(${CMAKE_BINARY_DIR}/include)  # config.h etc., "public" head
 string(TOUPPER "${CMAKE_BUILD_TYPE}" uppercase_CMAKE_BUILD_TYPE)
 string(APPEND LEANC_OPTS " ${CMAKE_CXX_FLAGS_${uppercase_CMAKE_BUILD_TYPE}}")
 
-# Do embed flag for finding system headers and libraries in dev builds
+# Do embed flag for finding system libraries in dev builds
 if(CMAKE_OSX_SYSROOT AND NOT LEAN_STANDALONE)
-  string(APPEND LEANC_EXTRA_CC_FLAGS " ${CMAKE_CXX_SYSROOT_FLAG}${CMAKE_OSX_SYSROOT}")
-  string(APPEND LEAN_EXTRA_LINKER_FLAGS " ${CMAKE_CXX_SYSROOT_FLAG}${CMAKE_OSX_SYSROOT}")
+  string(APPEND LEANC_EXTRA_FLAGS " ${CMAKE_CXX_SYSROOT_FLAG}${CMAKE_OSX_SYSROOT}")
 endif()
 
 add_subdirectory(initialize)
@@ -593,10 +522,6 @@ if(${STAGE} GREATER 1)
   endif()
 else()
   add_subdirectory(runtime)
-  if("${CMAKE_SYSTEM_NAME}" MATCHES "Emscripten")
-    add_dependencies(leanrt libuv)
-    add_dependencies(leanrt_initial-exec libuv)
-  endif()
 
   add_subdirectory(util)
   set(LEAN_OBJS ${LEAN_OBJS} $<TARGET_OBJECTS:util>)
@@ -619,7 +544,7 @@ else()
     OUTPUT_NAME leancpp)
 endif()
 
-if((${STAGE} GREATER 0) AND CADICAL AND INSTALL_CADICAL)
+if((${STAGE} GREATER 0) AND CADICAL)
   add_custom_target(copy-cadical
     COMMAND cmake -E copy_if_different "${CADICAL}" "${CMAKE_BINARY_DIR}/bin/cadical${CMAKE_EXECUTABLE_SUFFIX}")
   add_dependencies(leancpp copy-cadical)
@@ -637,10 +562,7 @@ if (${CMAKE_SYSTEM_NAME} MATCHES "Emscripten")
   # simple. (And we are not interested in `Lake` anyway.) To use dynamic
   # linking, we would probably have to set MAIN_MODULE=2 on `leanshared`,
   # SIDE_MODULE=2 on `lean`, and set CMAKE_SHARED_LIBRARY_SUFFIX to ".js".
-  # We set `ERROR_ON_UNDEFINED_SYMBOLS=0` because our build of LibUV does not
-  # define all symbols, see the comment about LibUV on WebAssembly further up
-  # in this file.
-  string(APPEND LEAN_EXE_LINKER_FLAGS " ${LIB}/temp/libleanshell.a ${TOOLCHAIN_STATIC_LINKER_FLAGS} ${EMSCRIPTEN_SETTINGS} -lnodefs.js -s EXIT_RUNTIME=1 -s MAIN_MODULE=1 -s LINKABLE=1 -s EXPORT_ALL=1 -s ERROR_ON_UNDEFINED_SYMBOLS=0")
+  string(APPEND LEAN_EXE_LINKER_FLAGS " ${LIB}/temp/libleanshell.a ${TOOLCHAIN_STATIC_LINKER_FLAGS} ${EMSCRIPTEN_SETTINGS} -lnodefs.js -s EXIT_RUNTIME=1 -s MAIN_MODULE=1 -s LINKABLE=1 -s EXPORT_ALL=1")
 endif()
 
 # Build the compiler using the bootstrapped C sources for stage0, and use
@@ -741,7 +663,7 @@ file(COPY ${LEAN_SOURCE_DIR}/bin/leanmake DESTINATION ${CMAKE_BINARY_DIR}/bin)
 
 install(DIRECTORY "${CMAKE_BINARY_DIR}/bin/" USE_SOURCE_PERMISSIONS DESTINATION bin)
 
-if (${STAGE} GREATER 0 AND CADICAL AND INSTALL_CADICAL)
+if (${STAGE} GREATER 0 AND CADICAL)
   install(PROGRAMS "${CADICAL}" DESTINATION bin)
 endif()
 

src/Init.lean

@@ -35,5 +35,3 @@ import Init.Ext
 import Init.Omega
 import Init.MacroTrace
 import Init.Grind
-import Init.While
-import Init.Syntax

src/Init/Classical.lean

@@ -80,8 +80,6 @@ noncomputable scoped instance (priority := low) propDecidable (a : Prop) : Decid
 noncomputable def decidableInhabited (a : Prop) : Inhabited (Decidable a) where
   default := inferInstance
 
-instance (a : Prop) : Nonempty (Decidable a) := ⟨propDecidable a⟩
-
 noncomputable def typeDecidableEq (α : Sort u) : DecidableEq α :=
   fun _ _ => inferInstance
 

src/Init/Control/Basic.lean

@@ -8,42 +8,6 @@ import Init.Core
 
 universe u v w
 
-/--
-A `ForIn'` instance, which handles `for h : x in c do`,
-can also handle `for x in x do` by ignoring `h`, and so provides a `ForIn` instance.
-
-Note that this instance will cause a potentially non-defeq duplication if both `ForIn` and `ForIn'`
-instances are provided for the same type.
--/
--- We set the priority to 500 so it is below the default,
--- but still above the low priority instance from `Stream`.
-instance (priority := 500) instForInOfForIn' [ForIn' m ρ α d] : ForIn m ρ α where
-  forIn x b f := forIn' x b fun a _ => f a
-
-@[simp] theorem forIn'_eq_forIn [d : Membership α ρ] [ForIn' m ρ α d] {β} [Monad m] (x : ρ) (b : β)
-    (f : (a : α) → a ∈ x → β → m (ForInStep β)) (g : (a : α) → β → m (ForInStep β))
-    (h : ∀ a m b, f a m b = g a b) :
-    forIn' x b f = forIn x b g := by
-  simp [instForInOfForIn']
-  congr
-  apply funext
-  intro a
-  apply funext
-  intro m
-  apply funext
-  intro b
-  simp [h]
-  rfl
-
-/-- Extract the value from a `ForInStep`, ignoring whether it is `done` or `yield`. -/
-def ForInStep.value (x : ForInStep α) : α :=
-  match x with
-  | ForInStep.done b => b
-  | ForInStep.yield b => b
-
-@[simp] theorem ForInStep.value_done (b : β) : (ForInStep.done b).value = b := rfl
-@[simp] theorem ForInStep.value_yield (b : β) : (ForInStep.yield b).value = b := rfl
-
 @[reducible]
 def Functor.mapRev {f : Type u → Type v} [Functor f] {α β : Type u} : f α → (α → β) → f β :=
   fun a f => f <$> a

src/Init/Control/Lawful/Basic.lean

@@ -33,10 +33,6 @@ attribute [simp] id_map
 @[simp] theorem id_map' [Functor m] [LawfulFunctor m] (x : m α) : (fun a => a) <$> x = x :=
   id_map x
 
-@[simp] theorem Functor.map_map [Functor f] [LawfulFunctor f] (m : α → β) (g : β → γ) (x : f α) :
-    g <$> m <$> x = (fun a => g (m a)) <$> x :=
-  (comp_map _ _ _).symm
-
 /--
 The `Applicative` typeclass only contains the operations of an applicative functor.
 `LawfulApplicative` further asserts that these operations satisfy the laws of an applicative functor:
@@ -87,16 +83,12 @@ class LawfulMonad (m : Type u → Type v) [Monad m] extends LawfulApplicative m
   seq_assoc x g h := (by simp [← bind_pure_comp, ← bind_map, bind_assoc, pure_bind])
 
 export LawfulMonad (bind_pure_comp bind_map pure_bind bind_assoc)
-attribute [simp] pure_bind bind_assoc bind_pure_comp
+attribute [simp] pure_bind bind_assoc
 
 @[simp] theorem bind_pure [Monad m] [LawfulMonad m] (x : m α) : x >>= pure = x := by
   show x >>= (fun a => pure (id a)) = x
   rw [bind_pure_comp, id_map]
 
-/--
-Use `simp [← bind_pure_comp]` rather than `simp [map_eq_pure_bind]`,
-as `bind_pure_comp` is in the default simp set, so also using `map_eq_pure_bind` would cause a loop.
--/
 theorem map_eq_pure_bind [Monad m] [LawfulMonad m] (f : α → β) (x : m α) : f <$> x = x >>= fun a => pure (f a) := by
   rw [← bind_pure_comp]
 
@@ -117,24 +109,10 @@ theorem seq_eq_bind {α β : Type u} [Monad m] [LawfulMonad m] (mf : m (α →
 
 theorem seqRight_eq_bind [Monad m] [LawfulMonad m] (x : m α) (y : m β) : x *> y = x >>= fun _ => y := by
   rw [seqRight_eq]
-  simp only [map_eq_pure_bind, const, seq_eq_bind_map, bind_assoc, pure_bind, id_eq, bind_pure]
+  simp [map_eq_pure_bind, seq_eq_bind_map, const]
 
 theorem seqLeft_eq_bind [Monad m] [LawfulMonad m] (x : m α) (y : m β) : x <* y = x >>= fun a => y >>= fun _ => pure a := by
-  rw [seqLeft_eq]
-  simp only [map_eq_pure_bind, seq_eq_bind_map, bind_assoc, pure_bind, const_apply]
-
-@[simp] theorem map_bind [Monad m] [LawfulMonad m] (f : β → γ) (x : m α) (g : α → m β) :
-    f <$> (x >>= g) = x >>= fun a => f <$> g a := by
-  rw [← bind_pure_comp, LawfulMonad.bind_assoc]
-  simp [bind_pure_comp]
-
-@[simp] theorem bind_map_left [Monad m] [LawfulMonad m] (f : α → β) (x : m α) (g : β → m γ) :
-    ((f <$> x) >>= fun b => g b) = (x >>= fun a => g (f a)) := by
-  rw [← bind_pure_comp]
-  simp only [bind_assoc, pure_bind]
-
-@[simp] theorem Functor.map_unit [Monad m] [LawfulMonad m] {a : m PUnit} : (fun _ => PUnit.unit) <$> a = a := by
-  simp [map]
+  rw [seqLeft_eq]; simp [map_eq_pure_bind, seq_eq_bind_map]
 
 /--
 An alternative constructor for `LawfulMonad` which has more
@@ -183,9 +161,9 @@ end Id
 
 instance : LawfulMonad Option := LawfulMonad.mk'
   (id_map := fun x => by cases x <;> rfl)
-  (pure_bind := fun _ _ => rfl)
-  (bind_assoc := fun x _ _ => by cases x <;> rfl)
-  (bind_pure_comp := fun _ x => by cases x <;> rfl)
+  (pure_bind := fun x f => rfl)
+  (bind_assoc := fun x f g => by cases x <;> rfl)
+  (bind_pure_comp := fun f x => by cases x <;> rfl)
 
 instance : LawfulApplicative Option := inferInstance
 instance : LawfulFunctor Option := inferInstance

src/Init/Control/Lawful/Instances.lean

@@ -7,7 +7,6 @@ prelude
 import Init.Control.Lawful.Basic
 import Init.Control.Except
 import Init.Control.StateRef
-import Init.Ext
 
 open Function
 
@@ -15,7 +14,7 @@ open Function
 
 namespace ExceptT
 
-@[ext] theorem ext {x y : ExceptT ε m α} (h : x.run = y.run) : x = y := by
+theorem ext {x y : ExceptT ε m α} (h : x.run = y.run) : x = y := by
   simp [run] at h
   assumption
 
@@ -26,7 +25,7 @@ namespace ExceptT
 @[simp] theorem run_throw [Monad m] : run (throw e : ExceptT ε m β) = pure (Except.error e) := rfl
 
 @[simp] theorem run_bind_lift [Monad m] [LawfulMonad m] (x : m α) (f : α → ExceptT ε m β) : run (ExceptT.lift x >>= f : ExceptT ε m β) = x >>= fun a => run (f a) := by
-  simp [ExceptT.run, ExceptT.lift, bind, ExceptT.bind, ExceptT.mk, ExceptT.bindCont]
+  simp[ExceptT.run, ExceptT.lift, bind, ExceptT.bind, ExceptT.mk, ExceptT.bindCont, map_eq_pure_bind]
 
 @[simp] theorem bind_throw [Monad m] [LawfulMonad m] (f : α → ExceptT ε m β) : (throw e >>= f) = throw e := by
   simp [throw, throwThe, MonadExceptOf.throw, bind, ExceptT.bind, ExceptT.bindCont, ExceptT.mk]
@@ -44,7 +43,7 @@ theorem run_bind [Monad m] (x : ExceptT ε m α)
 
 @[simp] theorem run_map [Monad m] [LawfulMonad m] (f : α → β) (x : ExceptT ε m α)
     : (f <$> x).run = Except.map f <$> x.run := by
-  simp [Functor.map, ExceptT.map, ←bind_pure_comp]
+  simp [Functor.map, ExceptT.map, map_eq_pure_bind]
   apply bind_congr
   intro a; cases a <;> simp [Except.map]
 
@@ -63,7 +62,7 @@ protected theorem seqLeft_eq {α β ε : Type u} {m : Type u → Type v} [Monad
   intro
   | Except.error _ => simp
   | Except.ok _ =>
-    simp [←bind_pure_comp]; apply bind_congr; intro b;
+    simp [map_eq_pure_bind]; apply bind_congr; intro b;
     cases b <;> simp [comp, Except.map, const]
 
 protected theorem seqRight_eq [Monad m] [LawfulMonad m] (x : ExceptT ε m α) (y : ExceptT ε m β) : x *> y = const α id <$> x <*> y := by
@@ -85,19 +84,14 @@ instance [Monad m] [LawfulMonad m] : LawfulMonad (ExceptT ε m) where
   pure_bind      := by intros; apply ext; simp [run_bind]
   bind_assoc     := by intros; apply ext; simp [run_bind]; apply bind_congr; intro a; cases a <;> simp
 
-@[simp] theorem map_throw [Monad m] [LawfulMonad m] {α β : Type _} (f : α → β) (e : ε) :
-    f <$> (throw e : ExceptT ε m α) = (throw e : ExceptT ε m β) := by
-  simp only [ExceptT.instMonad, ExceptT.map, ExceptT.mk, throw, throwThe, MonadExceptOf.throw,
-    pure_bind]
-
 end ExceptT
 
 /-! # Except -/
 
 instance : LawfulMonad (Except ε) := LawfulMonad.mk'
   (id_map := fun x => by cases x <;> rfl)
-  (pure_bind := fun _ _ => rfl)
-  (bind_assoc := fun a _ _ => by cases a <;> rfl)
+  (pure_bind := fun a f => rfl)
+  (bind_assoc := fun a f g => by cases a <;> rfl)
 
 instance : LawfulApplicative (Except ε) := inferInstance
 instance : LawfulFunctor (Except ε) := inferInstance
@@ -106,7 +100,7 @@ instance : LawfulFunctor (Except ε) := inferInstance
 
 namespace ReaderT
 
-@[ext] theorem ext {x y : ReaderT ρ m α} (h : ∀ ctx, x.run ctx = y.run ctx) : x = y := by
+theorem ext {x y : ReaderT ρ m α} (h : ∀ ctx, x.run ctx = y.run ctx) : x = y := by
   simp [run] at h
   exact funext h
 
@@ -168,7 +162,7 @@ instance [Monad m] [LawfulMonad m] : LawfulMonad (StateRefT' ω σ m) :=
 
 namespace StateT
 
-@[ext] theorem ext {x y : StateT σ m α} (h : ∀ s, x.run s = y.run s) : x = y :=
+theorem ext {x y : StateT σ m α} (h : ∀ s, x.run s = y.run s) : x = y :=
   funext h
 
 @[simp] theorem run'_eq [Monad m] (x : StateT σ m α) (s : σ) : run' x s = (·.1) <$> run x s :=
@@ -181,7 +175,7 @@ namespace StateT
   simp [bind, StateT.bind, run]
 
 @[simp] theorem run_map {α β σ : Type u} [Monad m] [LawfulMonad m] (f : α → β) (x : StateT σ m α) (s : σ) : (f <$> x).run s = (fun (p : α × σ) => (f p.1, p.2)) <$> x.run s := by
-  simp [Functor.map, StateT.map, run, ←bind_pure_comp]
+  simp [Functor.map, StateT.map, run, map_eq_pure_bind]
 
 @[simp] theorem run_get [Monad m] (s : σ)    : (get : StateT σ m σ).run s = pure (s, s) := rfl
 
@@ -216,13 +210,13 @@ theorem run_bind_lift {α σ : Type u} [Monad m] [LawfulMonad m] (x : m α) (f :
 
 theorem seqRight_eq [Monad m] [LawfulMonad m] (x : StateT σ m α) (y : StateT σ m β) : x *> y = const α id <$> x <*> y := by
   apply ext; intro s
-  simp [←bind_pure_comp, const]
+  simp [map_eq_pure_bind, const]
   apply bind_congr; intro p; cases p
   simp [Prod.eta]
 
 theorem seqLeft_eq [Monad m] [LawfulMonad m] (x : StateT σ m α) (y : StateT σ m β) : x <* y = const β <$> x <*> y := by
   apply ext; intro s
-  simp [←bind_pure_comp]
+  simp [map_eq_pure_bind]
 
 instance [Monad m] [LawfulMonad m] : LawfulMonad (StateT σ m) where
   id_map         := by intros; apply ext; intros; simp[Prod.eta]
@@ -230,7 +224,7 @@ instance [Monad m] [LawfulMonad m] : LawfulMonad (StateT σ m) where
   seqLeft_eq     := seqLeft_eq
   seqRight_eq    := seqRight_eq
   pure_seq       := by intros; apply ext; intros; simp
-  bind_pure_comp := by intros; apply ext; intros; simp
+  bind_pure_comp := by intros; apply ext; intros; simp; apply LawfulMonad.bind_pure_comp
   bind_map       := by intros; rfl
   pure_bind      := by intros; apply ext; intros; simp
   bind_assoc     := by intros; apply ext; intros; simp

src/Init/Control/StateRef.lean

@@ -6,7 +6,8 @@ Authors: Leonardo de Moura, Sebastian Ullrich
 The State monad transformer using IO references.
 -/
 prelude
-import Init.System.ST
+import Init.System.IO
+import Init.Control.State
 
 def StateRefT' (ω : Type) (σ : Type) (m : Type → Type) (α : Type) : Type := ReaderT (ST.Ref ω σ) m α
 

src/Init/Conv.lean

@@ -7,7 +7,6 @@ Notation for operators defined at Prelude.lean
 -/
 prelude
 import Init.Tactics
-import Init.Meta
 
 namespace Lean.Parser.Tactic.Conv
 
@@ -47,20 +46,12 @@ scoped syntax (name := withAnnotateState)
 /-- `skip` does nothing. -/
 syntax (name := skip) "skip" : conv
 
-/--
-Traverses into the left subterm of a binary operator.
-
-In general, for an `n`-ary operator, it traverses into the second to last argument.
-It is a synonym for `arg -2`.
--/
+/-- Traverses into the left subterm of a binary operator.
+(In general, for an `n`-ary operator, it traverses into the second to last argument.) -/
 syntax (name := lhs) "lhs" : conv
 
-/--
-Traverses into the right subterm of a binary operator.
-
-In general, for an `n`-ary operator, it traverses into the last argument.
-It is a synonym for `arg -1`.
--/
+/-- Traverses into the right subterm of a binary operator.
+(In general, for an `n`-ary operator, it traverses into the last argument.) -/
 syntax (name := rhs) "rhs" : conv
 
 /-- Traverses into the function of a (unary) function application.
@@ -83,17 +74,13 @@ subgoals for all the function arguments. For example, if the target is `f x y` t
 `congr` produces two subgoals, one for `x` and one for `y`. -/
 syntax (name := congr) "congr" : conv
 
-syntax argArg := "@"? "-"? num
-
 /--
 * `arg i` traverses into the `i`'th argument of the target. For example if the
   target is `f a b c d` then `arg 1` traverses to `a` and `arg 3` traverses to `c`.
-  The index may be negative; `arg -1` traverses into the last argument,
-  `arg -2` into the second-to-last argument, and so on.
 * `arg @i` is the same as `arg i` but it counts all arguments instead of just the
   explicit arguments.
 * `arg 0` traverses into the function. If the target is `f a b c d`, `arg 0` traverses into `f`. -/
-syntax (name := arg) "arg " argArg : conv
+syntax (name := arg) "arg " "@"? num : conv
 
 /-- `ext x` traverses into a binder (a `fun x => e` or `∀ x, e` expression)
 to target `e`, introducing name `x` in the process. -/
@@ -143,11 +130,11 @@ For example, if we are searching for `f _` in `f (f a) = f b`:
 syntax (name := pattern) "pattern " (occs)? term : conv
 
 /-- `rw [thm]` rewrites the target using `thm`. See the `rw` tactic for more information. -/
-syntax (name := rewrite) "rewrite" optConfig rwRuleSeq : conv
+syntax (name := rewrite) "rewrite" (config)? rwRuleSeq : conv
 
 /-- `simp [thm]` performs simplification using `thm` and marked `@[simp]` lemmas.
 See the `simp` tactic for more information. -/
-syntax (name := simp) "simp" optConfig (discharger)? (&" only")?
+syntax (name := simp) "simp" (config)? (discharger)? (&" only")?
   (" [" withoutPosition((simpStar <|> simpErase <|> simpLemma),*) "]")? : conv
 
 /--
@@ -164,7 +151,7 @@ example (a : Nat): (0 + 0) = a - a := by
     rw [← Nat.sub_self a]
 ```
 -/
-syntax (name := dsimp) "dsimp" optConfig (discharger)? (&" only")?
+syntax (name := dsimp) "dsimp" (config)? (discharger)? (&" only")?
   (" [" withoutPosition((simpErase <|> simpLemma),*) "]")? : conv
 
 /-- `simp_match` simplifies match expressions. For example,
@@ -260,12 +247,12 @@ macro (name := failIfSuccess) tk:"fail_if_success " s:convSeq : conv =>
 
 /-- `rw [rules]` applies the given list of rewrite rules to the target.
 See the `rw` tactic for more information. -/
-macro "rw" c:optConfig s:rwRuleSeq : conv => `(conv| rewrite $c:optConfig $s)
+macro "rw" c:(config)? s:rwRuleSeq : conv => `(conv| rewrite $[$c]? $s)
 
-/-- `erw [rules]` is a shorthand for `rw (transparency := .default) [rules]`.
+/-- `erw [rules]` is a shorthand for `rw (config := { transparency := .default }) [rules]`.
 This does rewriting up to unfolding of regular definitions (by comparison to regular `rw`
 which only unfolds `@[reducible]` definitions). -/
-macro "erw" c:optConfig s:rwRuleSeq : conv => `(conv| rw $[$(getConfigItems c)]* (transparency := .default) $s:rwRuleSeq)
+macro "erw" s:rwRuleSeq : conv => `(conv| rw (config := { transparency := .default }) $s)
 
 /-- `args` traverses into all arguments. Synonym for `congr`. -/
 macro "args" : conv => `(conv| congr)
@@ -276,7 +263,7 @@ macro "right" : conv => `(conv| rhs)
 /-- `intro` traverses into binders. Synonym for `ext`. -/
 macro "intro" xs:(ppSpace colGt ident)* : conv => `(conv| ext $xs*)
 
-syntax enterArg := ident <|> argArg
+syntax enterArg := ident <|> ("@"? num)
 
 /-- `enter [arg, ...]` is a compact way to describe a path to a subterm.
 It is a shorthand for other conv tactics as follows:
@@ -285,7 +272,12 @@ It is a shorthand for other conv tactics as follows:
 * `enter [x]` (where `x` is an identifier) is equivalent to `ext x`.
 For example, given the target `f (g a (fun x => x b))`, `enter [1, 2, x, 1]`
 will traverse to the subterm `b`. -/
-syntax (name := enter) "enter" " [" withoutPosition(enterArg,+) "]" : conv
+syntax "enter" " [" withoutPosition(enterArg,+) "]" : conv
+macro_rules
+  | `(conv| enter [$i:num]) => `(conv| arg $i)
+  | `(conv| enter [@$i]) => `(conv| arg @$i)
+  | `(conv| enter [$id:ident]) => `(conv| ext $id)
+  | `(conv| enter [$arg, $args,*]) => `(conv| (enter [$arg]; enter [$args,*]))
 
 /-- The `apply thm` conv tactic is the same as `apply thm` the tactic.
 There are no restrictions on `thm`, but strange results may occur if `thm`

src/Init/Core.lean

@@ -324,6 +324,7 @@ class ForIn' (m : Type u₁ → Type u₂) (ρ : Type u) (α : outParam (Type v)
 
 export ForIn' (forIn')
 
+
 /--
 Auxiliary type used to compile `do` notation. It is used when compiling a do block
 nested inside a combinator like `tryCatch`. It encodes the possible ways the
@@ -822,7 +823,6 @@ theorem iff_iff_implies_and_implies {a b : Prop} : (a ↔ b) ↔ (a → b) ∧ (
 protected theorem Iff.rfl {a : Prop} : a ↔ a :=
   Iff.refl a
 
--- And, also for backward compatibility, we try `Iff.rfl.` using `exact` (see #5366)
 macro_rules | `(tactic| rfl) => `(tactic| exact Iff.rfl)
 
 theorem Iff.of_eq (h : a = b) : a ↔ b := h ▸ Iff.rfl
@@ -837,9 +837,6 @@ instance : Trans Iff Iff Iff where
 theorem Eq.comm {a b : α} : a = b ↔ b = a := Iff.intro Eq.symm Eq.symm
 theorem eq_comm {a b : α} : a = b ↔ b = a := Eq.comm
 
-theorem HEq.comm {a : α} {b : β} : HEq a b ↔ HEq b a := Iff.intro HEq.symm HEq.symm
-theorem heq_comm {a : α} {b : β} : HEq a b ↔ HEq b a := HEq.comm
-
 @[symm] theorem Iff.symm (h : a ↔ b) : b ↔ a := Iff.intro h.mpr h.mp
 theorem Iff.comm: (a ↔ b) ↔ (b ↔ a) := Iff.intro Iff.symm Iff.symm
 theorem iff_comm : (a ↔ b) ↔ (b ↔ a) := Iff.comm
@@ -861,21 +858,16 @@ theorem Exists.elim {α : Sort u} {p : α → Prop} {b : Prop}
 
 /-! # Decidable -/
 
-@[simp] theorem decide_true (h : Decidable True) : @decide True h = true :=
+theorem decide_true_eq_true (h : Decidable True) : @decide True h = true :=
   match h with
   | isTrue _  => rfl
   | isFalse h => False.elim <| h ⟨⟩
 
-@[simp] theorem decide_false (h : Decidable False) : @decide False h = false :=
+theorem decide_false_eq_false (h : Decidable False) : @decide False h = false :=
   match h with
   | isFalse _ => rfl
   | isTrue h  => False.elim h
 
-set_option linter.missingDocs false in
-@[deprecated decide_true (since := "2024-11-05")] abbrev decide_true_eq_true := decide_true
-set_option linter.missingDocs false in
-@[deprecated decide_false (since := "2024-11-05")] abbrev decide_false_eq_false := decide_false
-
 /-- Similar to `decide`, but uses an explicit instance -/
 @[inline] def toBoolUsing {p : Prop} (d : Decidable p) : Bool :=
   decide (h := d)
@@ -1389,7 +1381,11 @@ gen_injective_theorems% Except
 gen_injective_theorems% EStateM.Result
 gen_injective_theorems% Lean.Name
 gen_injective_theorems% Lean.Syntax
-gen_injective_theorems% BitVec
+
+/-- Replacement for `Array.mk.injEq`; we avoid mentioning the constructor and prefer `List.toArray`. -/
+abbrev List.toArray_inj := @Array.mk.injEq
+
+attribute [deprecated List.toArray_inj (since := "2024-09-09")] Array.mk.injEq
 
 theorem Nat.succ.inj {m n : Nat} : m.succ = n.succ → m = n :=
   fun x => Nat.noConfusion x id
@@ -1869,8 +1865,7 @@ section
 variable {α : Type u}
 variable (r : α → α → Prop)
 
-instance Quotient.decidableEq {α : Sort u} {s : Setoid α} [d : ∀ (a b : α), Decidable (a ≈ b)]
-    : DecidableEq (Quotient s) :=
+instance {α : Sort u} {s : Setoid α} [d : ∀ (a b : α), Decidable (a ≈ b)] : DecidableEq (Quotient s) :=
   fun (q₁ q₂ : Quotient s) =>
     Quotient.recOnSubsingleton₂ q₁ q₂
       fun a₁ a₂ =>
@@ -1922,12 +1917,12 @@ represents an element of `Squash α` the same as `α` itself
 `Squash.lift` will extract a value in any subsingleton `β` from a function on `α`,
 while `Nonempty.rec` can only do the same when `β` is a proposition.
 -/
-def Squash (α : Sort u) := Quot (fun (_ _ : α) => True)
+def Squash (α : Type u) := Quot (fun (_ _ : α) => True)
 
 /-- The canonical quotient map into `Squash α`. -/
-def Squash.mk {α : Sort u} (x : α) : Squash α := Quot.mk _ x
+def Squash.mk {α : Type u} (x : α) : Squash α := Quot.mk _ x
 
-theorem Squash.ind {α : Sort u} {motive : Squash α → Prop} (h : ∀ (a : α), motive (Squash.mk a)) : ∀ (q : Squash α), motive q :=
+theorem Squash.ind {α : Type u} {motive : Squash α → Prop} (h : ∀ (a : α), motive (Squash.mk a)) : ∀ (q : Squash α), motive q :=
   Quot.ind h
 
 /-- If `β` is a subsingleton, then a function `α → β` lifts to `Squash α → β`. -/
@@ -1941,6 +1936,15 @@ instance : Subsingleton (Squash α) where
     apply Quot.sound
     trivial
 
+/-! # Relations -/
+
+/--
+`Antisymm (·≤·)` says that `(·≤·)` is antisymmetric, that is, `a ≤ b → b ≤ a → a = b`.
+-/
+class Antisymm {α : Sort u} (r : α → α → Prop) : Prop where
+  /-- An antisymmetric relation `(·≤·)` satisfies `a ≤ b → b ≤ a → a = b`. -/
+  antisymm {a b : α} : r a b → r b a → a = b
+
 namespace Lean
 /-! # Kernel reduction hints -/
 
@@ -2116,14 +2120,4 @@ instance : Commutative Or := ⟨fun _ _ => propext or_comm⟩
 instance : Commutative And := ⟨fun _ _ => propext and_comm⟩
 instance : Commutative Iff := ⟨fun _ _ => propext iff_comm⟩
 
-/--
-`Antisymm (·≤·)` says that `(·≤·)` is antisymmetric, that is, `a ≤ b → b ≤ a → a = b`.
--/
-class Antisymm (r : α → α → Prop) : Prop where
-  /-- An antisymmetric relation `(·≤·)` satisfies `a ≤ b → b ≤ a → a = b`. -/
-  antisymm {a b : α} : r a b → r b a → a = b
-
-@[deprecated Antisymm (since := "2024-10-16"), inherit_doc Antisymm]
-abbrev _root_.Antisymm (r : α → α → Prop) : Prop := Std.Antisymm r
-
 end Std

src/Init/Data.lean

@@ -19,9 +19,7 @@ import Init.Data.ByteArray
 import Init.Data.FloatArray
 import Init.Data.Fin
 import Init.Data.UInt
-import Init.Data.SInt
 import Init.Data.Float
-import Init.Data.Float32
 import Init.Data.Option
 import Init.Data.Ord
 import Init.Data.Random
@@ -42,6 +40,3 @@ import Init.Data.ULift
 import Init.Data.PLift
 import Init.Data.Zero
 import Init.Data.NeZero
-import Init.Data.Function
-import Init.Data.RArray
-import Init.Data.Vector

src/Init/Data/Array.lean

@@ -16,9 +16,3 @@ import Init.Data.Array.Lemmas
 import Init.Data.Array.TakeDrop
 import Init.Data.Array.Bootstrap
 import Init.Data.Array.GetLit
-import Init.Data.Array.MapIdx
-import Init.Data.Array.Set
-import Init.Data.Array.Monadic
-import Init.Data.Array.FinRange
-import Init.Data.Array.Perm
-import Init.Data.Array.Find

src/Init/Data/Array/Attach.lean

@@ -5,22 +5,10 @@ Authors: Joachim Breitner, Mario Carneiro
 -/
 prelude
 import Init.Data.Array.Mem
-import Init.Data.Array.Lemmas
 import Init.Data.List.Attach
 
 namespace Array
 
-/--
-`O(n)`. Partial map. If `f : Π a, P a → β` is a partial function defined on
-`a : α` satisfying `P`, then `pmap f l h` is essentially the same as `map f l`
-but is defined only when all members of `l` satisfy `P`, using the proof
-to apply `f`.
-
-We replace this at runtime with a more efficient version via the `csimp` lemma `pmap_eq_pmapImpl`.
--/
-def pmap {P : α → Prop} (f : ∀ a, P a → β) (l : Array α) (H : ∀ a ∈ l, P a) : Array β :=
-  (l.toList.pmap f (fun a m => H a (mem_def.mpr m))).toArray
-
 /--
 Unsafe implementation of `attachWith`, taking advantage of the fact that the representation of
 `Array {x // P x}` is the same as the input `Array α`.
@@ -38,546 +26,4 @@ Unsafe implementation of `attachWith`, taking advantage of the fact that the rep
   with the same elements but in the type `{x // x ∈ xs}`. -/
 @[inline] def attach (xs : Array α) : Array {x // x ∈ xs} := xs.attachWith _ fun _ => id
 
-@[simp] theorem _root_.List.attachWith_toArray {l : List α} {P : α → Prop} {H : ∀ x ∈ l.toArray, P x} :
-    l.toArray.attachWith P H = (l.attachWith P (by simpa using H)).toArray := by
-  simp [attachWith]
-
-@[simp] theorem _root_.List.attach_toArray {l : List α} :
-    l.toArray.attach = (l.attachWith (· ∈ l.toArray) (by simp)).toArray := by
-  simp [attach]
-
-@[simp] theorem _root_.List.pmap_toArray {l : List α} {P : α → Prop} {f : ∀ a, P a → β} {H : ∀ a ∈ l.toArray, P a} :
-    l.toArray.pmap f H = (l.pmap f (by simpa using H)).toArray := by
-  simp [pmap]
-
-@[simp] theorem toList_attachWith {l : Array α} {P : α → Prop} {H : ∀ x ∈ l, P x} :
-   (l.attachWith P H).toList = l.toList.attachWith P (by simpa [mem_toList] using H) := by
-  simp [attachWith]
-
-@[simp] theorem toList_attach {α : Type _} {l : Array α} :
-    l.attach.toList = l.toList.attachWith (· ∈ l) (by simp [mem_toList]) := by
-  simp [attach]
-
-@[simp] theorem toList_pmap {l : Array α} {P : α → Prop} {f : ∀ a, P a → β} {H : ∀ a ∈ l, P a} :
-    (l.pmap f H).toList = l.toList.pmap f (fun a m => H a (mem_def.mpr m)) := by
-  simp [pmap]
-
-/-- Implementation of `pmap` using the zero-copy version of `attach`. -/
-@[inline] private def pmapImpl {P : α → Prop} (f : ∀ a, P a → β) (l : Array α) (H : ∀ a ∈ l, P a) :
-    Array β := (l.attachWith _ H).map fun ⟨x, h'⟩ => f x h'
-
-@[csimp] private theorem pmap_eq_pmapImpl : @pmap = @pmapImpl := by
-  funext α β p f L h'
-  cases L
-  simp only [pmap, pmapImpl, List.attachWith_toArray, List.map_toArray, mk.injEq, List.map_attachWith]
-  apply List.pmap_congr_left
-  intro a m h₁ h₂
-  congr
-
-@[simp] theorem pmap_empty {P : α → Prop} (f : ∀ a, P a → β) : pmap f #[] (by simp) = #[] := rfl
-
-@[simp] theorem pmap_push {P : α → Prop} (f : ∀ a, P a → β) (a : α) (l : Array α) (h : ∀ b ∈ l.push a, P b) :
-    pmap f (l.push a) h =
-      (pmap f l (fun a m => by simp at h; exact h a (.inl m))).push (f a (h a (by simp))) := by
-  simp [pmap]
-
-@[simp] theorem attach_empty : (#[] : Array α).attach = #[] := rfl
-
-@[simp] theorem attachWith_empty {P : α → Prop} (H : ∀ x ∈ #[], P x) : (#[] : Array α).attachWith P H = #[] := rfl
-
-@[simp] theorem _root_.List.attachWith_mem_toArray {l : List α} :
-    l.attachWith (fun x => x ∈ l.toArray) (fun x h => by simpa using h) =
-      l.attach.map fun ⟨x, h⟩ => ⟨x, by simpa using h⟩ := by
-  simp only [List.attachWith, List.attach, List.map_pmap]
-  apply List.pmap_congr_left
-  simp
-
-@[simp]
-theorem pmap_eq_map (p : α → Prop) (f : α → β) (l : Array α) (H) :
-    @pmap _ _ p (fun a _ => f a) l H = map f l := by
-  cases l; simp
-
-theorem pmap_congr_left {p q : α → Prop} {f : ∀ a, p a → β} {g : ∀ a, q a → β} (l : Array α) {H₁ H₂}
-    (h : ∀ a ∈ l, ∀ (h₁ h₂), f a h₁ = g a h₂) : pmap f l H₁ = pmap g l H₂ := by
-  cases l
-  simp only [mem_toArray] at h
-  simp only [List.pmap_toArray, mk.injEq]
-  rw [List.pmap_congr_left _ h]
-
-theorem map_pmap {p : α → Prop} (g : β → γ) (f : ∀ a, p a → β) (l H) :
-    map g (pmap f l H) = pmap (fun a h => g (f a h)) l H := by
-  cases l
-  simp [List.map_pmap]
-
-theorem pmap_map {p : β → Prop} (g : ∀ b, p b → γ) (f : α → β) (l H) :
-    pmap g (map f l) H = pmap (fun a h => g (f a) h) l fun _ h => H _ (mem_map_of_mem _ h) := by
-  cases l
-  simp [List.pmap_map]
-
-theorem attach_congr {l₁ l₂ : Array α} (h : l₁ = l₂) :
-    l₁.attach = l₂.attach.map (fun x => ⟨x.1, h ▸ x.2⟩) := by
-  subst h
-  simp
-
-theorem attachWith_congr {l₁ l₂ : Array α} (w : l₁ = l₂) {P : α → Prop} {H : ∀ x ∈ l₁, P x} :
-    l₁.attachWith P H = l₂.attachWith P fun _ h => H _ (w ▸ h) := by
-  subst w
-  simp
-
-@[simp] theorem attach_push {a : α} {l : Array α} :
-    (l.push a).attach =
-      (l.attach.map (fun ⟨x, h⟩ => ⟨x, mem_push_of_mem a h⟩)).push ⟨a, by simp⟩ := by
-  cases l
-  rw [attach_congr (List.push_toArray _ _)]
-  simp [Function.comp_def]
-
-@[simp] theorem attachWith_push {a : α} {l : Array α} {P : α → Prop} {H : ∀ x ∈ l.push a, P x} :
-    (l.push a).attachWith P H =
-      (l.attachWith P (fun x h => by simp at H; exact H x (.inl h))).push ⟨a, H a (by simp)⟩ := by
-  cases l
-  simp [attachWith_congr (List.push_toArray _ _)]
-
-theorem pmap_eq_map_attach {p : α → Prop} (f : ∀ a, p a → β) (l H) :
-    pmap f l H = l.attach.map fun x => f x.1 (H _ x.2) := by
-  cases l
-  simp [List.pmap_eq_map_attach]
-
-theorem attach_map_coe (l : Array α) (f : α → β) :
-    (l.attach.map fun (i : {i // i ∈ l}) => f i) = l.map f := by
-  cases l
-  simp [List.attach_map_coe]
-
-theorem attach_map_val (l : Array α) (f : α → β) : (l.attach.map fun i => f i.val) = l.map f :=
-  attach_map_coe _ _
-
-@[simp]
-theorem attach_map_subtype_val (l : Array α) : l.attach.map Subtype.val = l := by
-  cases l; simp
-
-theorem attachWith_map_coe {p : α → Prop} (f : α → β) (l : Array α) (H : ∀ a ∈ l, p a) :
-    ((l.attachWith p H).map fun (i : { i // p i}) => f i) = l.map f := by
-  cases l; simp
-
-theorem attachWith_map_val {p : α → Prop} (f : α → β) (l : Array α) (H : ∀ a ∈ l, p a) :
-    ((l.attachWith p H).map fun i => f i.val) = l.map f :=
-  attachWith_map_coe _ _ _
-
-@[simp]
-theorem attachWith_map_subtype_val {p : α → Prop} (l : Array α) (H : ∀ a ∈ l, p a) :
-    (l.attachWith p H).map Subtype.val = l := by
-  cases l; simp
-
-@[simp]
-theorem mem_attach (l : Array α) : ∀ x, x ∈ l.attach
-  | ⟨a, h⟩ => by
-    have := mem_map.1 (by rw [attach_map_subtype_val] <;> exact h)
-    rcases this with ⟨⟨_, _⟩, m, rfl⟩
-    exact m
-
-@[simp]
-theorem mem_pmap {p : α → Prop} {f : ∀ a, p a → β} {l H b} :
-    b ∈ pmap f l H ↔ ∃ (a : _) (h : a ∈ l), f a (H a h) = b := by
-  simp only [pmap_eq_map_attach, mem_map, mem_attach, true_and, Subtype.exists, eq_comm]
-
-theorem mem_pmap_of_mem {p : α → Prop} {f : ∀ a, p a → β} {l H} {a} (h : a ∈ l) :
-    f a (H a h) ∈ pmap f l H := by
-  rw [mem_pmap]
-  exact ⟨a, h, rfl⟩
-
-@[simp]
-theorem size_pmap {p : α → Prop} {f : ∀ a, p a → β} {l H} : (pmap f l H).size = l.size := by
-  cases l; simp
-
-@[simp]
-theorem size_attach {L : Array α} : L.attach.size = L.size := by
-  cases L; simp
-
-@[simp]
-theorem size_attachWith {p : α → Prop} {l : Array α} {H} : (l.attachWith p H).size = l.size := by
-  cases l; simp
-
-@[simp]
-theorem pmap_eq_empty_iff {p : α → Prop} {f : ∀ a, p a → β} {l H} : pmap f l H = #[] ↔ l = #[] := by
-  cases l; simp
-
-theorem pmap_ne_empty_iff {P : α → Prop} (f : (a : α) → P a → β) {xs : Array α}
-    (H : ∀ (a : α), a ∈ xs → P a) : xs.pmap f H ≠ #[] ↔ xs ≠ #[] := by
-  cases xs; simp
-
-theorem pmap_eq_self {l : Array α} {p : α → Prop} (hp : ∀ (a : α), a ∈ l → p a)
-    (f : (a : α) → p a → α) : l.pmap f hp = l ↔ ∀ a (h : a ∈ l), f a (hp a h) = a := by
-  cases l; simp [List.pmap_eq_self]
-
-@[simp]
-theorem attach_eq_empty_iff {l : Array α} : l.attach = #[] ↔ l = #[] := by
-  cases l; simp
-
-theorem attach_ne_empty_iff {l : Array α} : l.attach ≠ #[] ↔ l ≠ #[] := by
-  cases l; simp
-
-@[simp]
-theorem attachWith_eq_empty_iff {l : Array α} {P : α → Prop} {H : ∀ a ∈ l, P a} :
-    l.attachWith P H = #[] ↔ l = #[] := by
-  cases l; simp
-
-theorem attachWith_ne_empty_iff {l : Array α} {P : α → Prop} {H : ∀ a ∈ l, P a} :
-    l.attachWith P H ≠ #[] ↔ l ≠ #[] := by
-  cases l; simp
-
-@[simp]
-theorem getElem?_pmap {p : α → Prop} (f : ∀ a, p a → β) {l : Array α} (h : ∀ a ∈ l, p a) (n : Nat) :
-    (pmap f l h)[n]? = Option.pmap f l[n]? fun x H => h x (mem_of_getElem? H) := by
-  cases l; simp
-
-@[simp]
-theorem getElem_pmap {p : α → Prop} (f : ∀ a, p a → β) {l : Array α} (h : ∀ a ∈ l, p a) {n : Nat}
-    (hn : n < (pmap f l h).size) :
-    (pmap f l h)[n] =
-      f (l[n]'(@size_pmap _ _ p f l h ▸ hn))
-        (h _ (getElem_mem (@size_pmap _ _ p f l h ▸ hn))) := by
-  cases l; simp
-
-@[simp]
-theorem getElem?_attachWith {xs : Array α} {i : Nat} {P : α → Prop} {H : ∀ a ∈ xs, P a} :
-    (xs.attachWith P H)[i]? = xs[i]?.pmap Subtype.mk (fun _ a => H _ (mem_of_getElem? a)) :=
-  getElem?_pmap ..
-
-@[simp]
-theorem getElem?_attach {xs : Array α} {i : Nat} :
-    xs.attach[i]? = xs[i]?.pmap Subtype.mk (fun _ a => mem_of_getElem? a) :=
-  getElem?_attachWith
-
-@[simp]
-theorem getElem_attachWith {xs : Array α} {P : α → Prop} {H : ∀ a ∈ xs, P a}
-    {i : Nat} (h : i < (xs.attachWith P H).size) :
-    (xs.attachWith P H)[i] = ⟨xs[i]'(by simpa using h), H _ (getElem_mem (by simpa using h))⟩ :=
-  getElem_pmap _ _ h
-
-@[simp]
-theorem getElem_attach {xs : Array α} {i : Nat} (h : i < xs.attach.size) :
-    xs.attach[i] = ⟨xs[i]'(by simpa using h), getElem_mem (by simpa using h)⟩ :=
-  getElem_attachWith h
-
-theorem foldl_pmap (l : Array α) {P : α → Prop} (f : (a : α) → P a → β)
-  (H : ∀ (a : α), a ∈ l → P a) (g : γ → β → γ) (x : γ) :
-    (l.pmap f H).foldl g x = l.attach.foldl (fun acc a => g acc (f a.1 (H _ a.2))) x := by
-  rw [pmap_eq_map_attach, foldl_map]
-
-theorem foldr_pmap (l : Array α) {P : α → Prop} (f : (a : α) → P a → β)
-  (H : ∀ (a : α), a ∈ l → P a) (g : β → γ → γ) (x : γ) :
-    (l.pmap f H).foldr g x = l.attach.foldr (fun a acc => g (f a.1 (H _ a.2)) acc) x := by
-  rw [pmap_eq_map_attach, foldr_map]
-
-/--
-If we fold over `l.attach` with a function that ignores the membership predicate,
-we get the same results as folding over `l` directly.
-
-This is useful when we need to use `attach` to show termination.
-
-Unfortunately this can't be applied by `simp` because of the higher order unification problem,
-and even when rewriting we need to specify the function explicitly.
-See however `foldl_subtype` below.
--/
-theorem foldl_attach (l : Array α) (f : β → α → β) (b : β) :
-    l.attach.foldl (fun acc t => f acc t.1) b = l.foldl f b := by
-  rcases l with ⟨l⟩
-  simp only [List.attach_toArray, List.attachWith_mem_toArray, List.map_attach, size_toArray,
-    List.length_pmap, List.foldl_toArray', mem_toArray, List.foldl_subtype]
-  congr
-  ext
-  simpa using fun a => List.mem_of_getElem? a
-
-/--
-If we fold over `l.attach` with a function that ignores the membership predicate,
-we get the same results as folding over `l` directly.
-
-This is useful when we need to use `attach` to show termination.
-
-Unfortunately this can't be applied by `simp` because of the higher order unification problem,
-and even when rewriting we need to specify the function explicitly.
-See however `foldr_subtype` below.
--/
-theorem foldr_attach (l : Array α) (f : α → β → β) (b : β) :
-    l.attach.foldr (fun t acc => f t.1 acc) b = l.foldr f b := by
-  rcases l with ⟨l⟩
-  simp only [List.attach_toArray, List.attachWith_mem_toArray, List.map_attach, size_toArray,
-    List.length_pmap, List.foldr_toArray', mem_toArray, List.foldr_subtype]
-  congr
-  ext
-  simpa using fun a => List.mem_of_getElem? a
-
-theorem attach_map {l : Array α} (f : α → β) :
-    (l.map f).attach = l.attach.map (fun ⟨x, h⟩ => ⟨f x, mem_map_of_mem f h⟩) := by
-  cases l
-  ext <;> simp
-
-theorem attachWith_map {l : Array α} (f : α → β) {P : β → Prop} {H : ∀ (b : β), b ∈ l.map f → P b} :
-    (l.map f).attachWith P H = (l.attachWith (P ∘ f) (fun _ h => H _ (mem_map_of_mem f h))).map
-      fun ⟨x, h⟩ => ⟨f x, h⟩ := by
-  cases l
-  ext
-  · simp
-  · simp only [List.map_toArray, List.attachWith_toArray, List.getElem_toArray,
-      List.getElem_attachWith, List.getElem_map, Function.comp_apply]
-    erw [List.getElem_attachWith] -- Why is `erw` needed here?
-
-theorem map_attachWith {l : Array α} {P : α → Prop} {H : ∀ (a : α), a ∈ l → P a}
-    (f : { x // P x } → β) :
-    (l.attachWith P H).map f =
-      l.pmap (fun a (h : a ∈ l ∧ P a) => f ⟨a, H _ h.1⟩) (fun a h => ⟨h, H a h⟩) := by
-  cases l
-  ext <;> simp
-
-/-- See also `pmap_eq_map_attach` for writing `pmap` in terms of `map` and `attach`. -/
-theorem map_attach {l : Array α} (f : { x // x ∈ l } → β) :
-    l.attach.map f = l.pmap (fun a h => f ⟨a, h⟩) (fun _ => id) := by
-  cases l
-  ext <;> simp
-
-theorem attach_filterMap {l : Array α} {f : α → Option β} :
-    (l.filterMap f).attach = l.attach.filterMap
-      fun ⟨x, h⟩ => (f x).pbind (fun b m => some ⟨b, mem_filterMap.mpr ⟨x, h, m⟩⟩) := by
-  cases l
-  rw [attach_congr (List.filterMap_toArray f _)]
-  simp [List.attach_filterMap, List.map_filterMap, Function.comp_def]
-
-theorem attach_filter {l : Array α} (p : α → Bool) :
-    (l.filter p).attach = l.attach.filterMap
-      fun x => if w : p x.1 then some ⟨x.1, mem_filter.mpr ⟨x.2, w⟩⟩ else none := by
-  cases l
-  rw [attach_congr (List.filter_toArray p _)]
-  simp [List.attach_filter, List.map_filterMap, Function.comp_def]
-
--- We are still missing here `attachWith_filterMap` and `attachWith_filter`.
--- Also missing are `filterMap_attach`, `filter_attach`, `filterMap_attachWith` and `filter_attachWith`.
-
-theorem pmap_pmap {p : α → Prop} {q : β → Prop} (g : ∀ a, p a → β) (f : ∀ b, q b → γ) (l H₁ H₂) :
-    pmap f (pmap g l H₁) H₂ =
-      pmap (α := { x // x ∈ l }) (fun a h => f (g a h) (H₂ (g a h) (mem_pmap_of_mem a.2))) l.attach
-        (fun a _ => H₁ a a.2) := by
-  cases l
-  simp [List.pmap_pmap, List.pmap_map]
-
-@[simp] theorem pmap_append {p : ι → Prop} (f : ∀ a : ι, p a → α) (l₁ l₂ : Array ι)
-    (h : ∀ a ∈ l₁ ++ l₂, p a) :
-    (l₁ ++ l₂).pmap f h =
-      (l₁.pmap f fun a ha => h a (mem_append_left l₂ ha)) ++
-        l₂.pmap f fun a ha => h a (mem_append_right l₁ ha) := by
-  cases l₁
-  cases l₂
-  simp
-
-theorem pmap_append' {p : α → Prop} (f : ∀ a : α, p a → β) (l₁ l₂ : Array α)
-    (h₁ : ∀ a ∈ l₁, p a) (h₂ : ∀ a ∈ l₂, p a) :
-    ((l₁ ++ l₂).pmap f fun a ha => (mem_append.1 ha).elim (h₁ a) (h₂ a)) =
-      l₁.pmap f h₁ ++ l₂.pmap f h₂ :=
-  pmap_append f l₁ l₂ _
-
-@[simp] theorem attach_append (xs ys : Array α) :
-    (xs ++ ys).attach = xs.attach.map (fun ⟨x, h⟩ => ⟨x, mem_append_left ys h⟩) ++
-      ys.attach.map fun ⟨x, h⟩ => ⟨x, mem_append_right xs h⟩ := by
-  cases xs
-  cases ys
-  rw [attach_congr (List.append_toArray _ _)]
-  simp [List.attach_append, Function.comp_def]
-
-@[simp] theorem attachWith_append {P : α → Prop} {xs ys : Array α}
-    {H : ∀ (a : α), a ∈ xs ++ ys → P a} :
-    (xs ++ ys).attachWith P H = xs.attachWith P (fun a h => H a (mem_append_left ys h)) ++
-      ys.attachWith P (fun a h => H a (mem_append_right xs h)) := by
-  simp [attachWith, attach_append, map_pmap, pmap_append]
-
-@[simp] theorem pmap_reverse {P : α → Prop} (f : (a : α) → P a → β) (xs : Array α)
-    (H : ∀ (a : α), a ∈ xs.reverse → P a) :
-    xs.reverse.pmap f H = (xs.pmap f (fun a h => H a (by simpa using h))).reverse := by
-  induction xs <;> simp_all
-
-theorem reverse_pmap {P : α → Prop} (f : (a : α) → P a → β) (xs : Array α)
-    (H : ∀ (a : α), a ∈ xs → P a) :
-    (xs.pmap f H).reverse = xs.reverse.pmap f (fun a h => H a (by simpa using h)) := by
-  rw [pmap_reverse]
-
-@[simp] theorem attachWith_reverse {P : α → Prop} {xs : Array α}
-    {H : ∀ (a : α), a ∈ xs.reverse → P a} :
-    xs.reverse.attachWith P H =
-      (xs.attachWith P (fun a h => H a (by simpa using h))).reverse := by
-  cases xs
-  simp
-
-theorem reverse_attachWith {P : α → Prop} {xs : Array α}
-    {H : ∀ (a : α), a ∈ xs → P a} :
-    (xs.attachWith P H).reverse = (xs.reverse.attachWith P (fun a h => H a (by simpa using h))) := by
-  cases xs
-  simp
-
-@[simp] theorem attach_reverse (xs : Array α) :
-    xs.reverse.attach = xs.attach.reverse.map fun ⟨x, h⟩ => ⟨x, by simpa using h⟩ := by
-  cases xs
-  rw [attach_congr (List.reverse_toArray _)]
-  simp
-
-theorem reverse_attach (xs : Array α) :
-    xs.attach.reverse = xs.reverse.attach.map fun ⟨x, h⟩ => ⟨x, by simpa using h⟩ := by
-  cases xs
-  simp
-
-@[simp] theorem back?_pmap {P : α → Prop} (f : (a : α) → P a → β) (xs : Array α)
-    (H : ∀ (a : α), a ∈ xs → P a) :
-    (xs.pmap f H).back? = xs.attach.back?.map fun ⟨a, m⟩ => f a (H a m) := by
-  cases xs
-  simp
-
-@[simp] theorem back?_attachWith {P : α → Prop} {xs : Array α}
-    {H : ∀ (a : α), a ∈ xs → P a} :
-    (xs.attachWith P H).back? = xs.back?.pbind (fun a h => some ⟨a, H _ (mem_of_back?_eq_some h)⟩) := by
-  cases xs
-  simp
-
-@[simp]
-theorem back?_attach {xs : Array α} :
-    xs.attach.back? = xs.back?.pbind fun a h => some ⟨a, mem_of_back?_eq_some h⟩ := by
-  cases xs
-  simp
-
-/-! ## unattach
-
-`Array.unattach` is the (one-sided) inverse of `Array.attach`. It is a synonym for `Array.map Subtype.val`.
-
-We use it by providing a simp lemma `l.attach.unattach = l`, and simp lemmas which recognize higher order
-functions applied to `l : Array { x // p x }` which only depend on the value, not the predicate, and rewrite these
-in terms of a simpler function applied to `l.unattach`.
-
-Further, we provide simp lemmas that push `unattach` inwards.
--/
-
-/--
-A synonym for `l.map (·.val)`. Mostly this should not be needed by users.
-It is introduced as in intermediate step by lemmas such as `map_subtype`,
-and is ideally subsequently simplified away by `unattach_attach`.
-
-If not, usually the right approach is `simp [Array.unattach, -Array.map_subtype]` to unfold.
--/
-def unattach {α : Type _} {p : α → Prop} (l : Array { x // p x }) := l.map (·.val)
-
-@[simp] theorem unattach_nil {p : α → Prop} : (#[] : Array { x // p x }).unattach = #[] := rfl
-@[simp] theorem unattach_push {p : α → Prop} {a : { x // p x }} {l : Array { x // p x }} :
-    (l.push a).unattach = l.unattach.push a.1 := by
-  simp only [unattach, Array.map_push]
-
-@[simp] theorem size_unattach {p : α → Prop} {l : Array { x // p x }} :
-    l.unattach.size = l.size := by
-  unfold unattach
-  simp
-
-@[simp] theorem _root_.List.unattach_toArray {p : α → Prop} {l : List { x // p x }} :
-    l.toArray.unattach = l.unattach.toArray := by
-  simp only [unattach, List.map_toArray, List.unattach]
-
-@[simp] theorem toList_unattach {p : α → Prop} {l : Array { x // p x }} :
-    l.unattach.toList = l.toList.unattach := by
-  simp only [unattach, toList_map, List.unattach]
-
-@[simp] theorem unattach_attach {l : Array α} : l.attach.unattach = l := by
-  cases l
-  simp only [List.attach_toArray, List.unattach_toArray, List.unattach_attachWith]
-
-@[simp] theorem unattach_attachWith {p : α → Prop} {l : Array α}
-    {H : ∀ a ∈ l, p a} :
-    (l.attachWith p H).unattach = l := by
-  cases l
-  simp
-
-@[simp] theorem getElem?_unattach {p : α → Prop} {l : Array { x // p x }} (i : Nat) :
-    l.unattach[i]? = l[i]?.map Subtype.val := by
-  simp [unattach]
-
-@[simp] theorem getElem_unattach
-    {p : α → Prop} {l : Array { x // p x }} (i : Nat) (h : i < l.unattach.size) :
-    l.unattach[i] = (l[i]'(by simpa using h)).1 := by
-  simp [unattach]
-
-/-! ### Recognizing higher order functions using a function that only depends on the value. -/
-
-/--
-This lemma identifies folds over arrays of subtypes, where the function only depends on the value, not the proposition,
-and simplifies these to the function directly taking the value.
--/
-theorem foldl_subtype {p : α → Prop} {l : Array { x // p x }}
-    {f : β → { x // p x } → β} {g : β → α → β} {x : β}
-    {hf : ∀ b x h, f b ⟨x, h⟩ = g b x} :
-    l.foldl f x = l.unattach.foldl g x := by
-  cases l
-  simp only [List.foldl_toArray', List.unattach_toArray]
-  rw [List.foldl_subtype] -- Why can't simp do this?
-  simp [hf]
-
-/-- Variant of `foldl_subtype` with side condition to check `stop = l.size`. -/
-@[simp] theorem foldl_subtype' {p : α → Prop} {l : Array { x // p x }}
-    {f : β → { x // p x } → β} {g : β → α → β} {x : β}
-    {hf : ∀ b x h, f b ⟨x, h⟩ = g b x} (h : stop = l.size) :
-    l.foldl f x 0 stop = l.unattach.foldl g x := by
-  subst h
-  rwa [foldl_subtype]
-
-/--
-This lemma identifies folds over arrays of subtypes, where the function only depends on the value, not the proposition,
-and simplifies these to the function directly taking the value.
--/
-theorem foldr_subtype {p : α → Prop} {l : Array { x // p x }}
-    {f : { x // p x } → β → β} {g : α → β → β} {x : β}
-    {hf : ∀ x h b, f ⟨x, h⟩ b = g x b} :
-    l.foldr f x = l.unattach.foldr g x := by
-  cases l
-  simp only [List.foldr_toArray', List.unattach_toArray]
-  rw [List.foldr_subtype]
-  simp [hf]
-
-/-- Variant of `foldr_subtype` with side condition to check `stop = l.size`. -/
-@[simp] theorem foldr_subtype' {p : α → Prop} {l : Array { x // p x }}
-    {f : { x // p x } → β → β} {g : α → β → β} {x : β}
-    {hf : ∀ x h b, f ⟨x, h⟩ b = g x b} (h : start = l.size) :
-    l.foldr f x start 0 = l.unattach.foldr g x := by
-  subst h
-  rwa [foldr_subtype]
-
-/--
-This lemma identifies maps over arrays of subtypes, where the function only depends on the value, not the proposition,
-and simplifies these to the function directly taking the value.
--/
-@[simp] theorem map_subtype {p : α → Prop} {l : Array { x // p x }}
-    {f : { x // p x } → β} {g : α → β} {hf : ∀ x h, f ⟨x, h⟩ = g x} :
-    l.map f = l.unattach.map g := by
-  cases l
-  simp only [List.map_toArray, List.unattach_toArray]
-  rw [List.map_subtype]
-  simp [hf]
-
-@[simp] theorem filterMap_subtype {p : α → Prop} {l : Array { x // p x }}
-    {f : { x // p x } → Option β} {g : α → Option β} {hf : ∀ x h, f ⟨x, h⟩ = g x} :
-    l.filterMap f = l.unattach.filterMap g := by
-  cases l
-  simp only [size_toArray, List.filterMap_toArray', List.unattach_toArray, List.length_unattach,
-    mk.injEq]
-  rw [List.filterMap_subtype]
-  simp [hf]
-
-@[simp] theorem unattach_filter {p : α → Prop} {l : Array { x // p x }}
-    {f : { x // p x } → Bool} {g : α → Bool} {hf : ∀ x h, f ⟨x, h⟩ = g x} :
-    (l.filter f).unattach = l.unattach.filter g := by
-  cases l
-  simp [hf]
-
-/-! ### Simp lemmas pushing `unattach` inwards. -/
-
-@[simp] theorem unattach_reverse {p : α → Prop} {l : Array { x // p x }} :
-    l.reverse.unattach = l.unattach.reverse := by
-  cases l
-  simp
-
-@[simp] theorem unattach_append {p : α → Prop} {l₁ l₂ : Array { x // p x }} :
-    (l₁ ++ l₂).unattach = l₁.unattach ++ l₂.unattach := by
-  cases l₁
-  cases l₂
-  simp
-
 end Array

src/Init/Data/Array/Basic.lean

@@ -7,13 +7,10 @@ prelude
 import Init.WFTactics
 import Init.Data.Nat.Basic
 import Init.Data.Fin.Basic
-import Init.Data.UInt.BasicAux
+import Init.Data.UInt.Basic
 import Init.Data.Repr
 import Init.Data.ToString.Basic
 import Init.GetElem
-import Init.Data.List.ToArrayImpl
-import Init.Data.Array.Set
-
 universe u v w
 
 /-! ### Array literal syntax -/
@@ -27,12 +24,9 @@ variable {α : Type u}
 
 namespace Array
 
-@[deprecated toList (since := "2024-10-13")] abbrev data := @toList
-
 /-! ### Preliminary theorems -/
 
-@[simp] theorem size_set (a : Array α) (i : Nat) (v : α) (h : i < a.size) :
-    (set a i v h).size = a.size :=
+@[simp] theorem size_set (a : Array α) (i : Fin a.size) (v : α) : (set a i v).size = a.size :=
   List.length_set ..
 
 @[simp] theorem size_push (a : Array α) (v : α) : (push a v).size = a.size + 1 :=
@@ -79,51 +73,11 @@ theorem ext' {as bs : Array α} (h : as.toList = bs.toList) : as = bs := by
 @[simp] theorem toArrayAux_eq (as : List α) (acc : Array α) : (as.toArrayAux acc).toList = acc.toList ++ as := by
   induction as generalizing acc <;> simp [*, List.toArrayAux, Array.push, List.append_assoc, List.concat_eq_append]
 
-@[simp] theorem toList_toArray (as : List α) : as.toArray.toList = as := rfl
+@[simp] theorem toList_toArray (as : List α) : as.toArray.toList = as := by
+  simp [List.toArray, Array.mkEmpty]
 
 @[simp] theorem size_toArray (as : List α) : as.toArray.size = as.length := by simp [size]
 
-@[simp] theorem getElem_toList {a : Array α} {i : Nat} (h : i < a.size) : a.toList[i] = a[i] := rfl
-
-@[simp] theorem getElem?_toList {a : Array α} {i : Nat} : a.toList[i]? = a[i]? := rfl
-
-/-- `a ∈ as` is a predicate which asserts that `a` is in the array `as`. -/
--- NB: This is defined as a structure rather than a plain def so that a lemma
--- like `sizeOf_lt_of_mem` will not apply with no actual arrays around.
-structure Mem (as : Array α) (a : α) : Prop where
-  val : a ∈ as.toList
-
-instance : Membership α (Array α) where
-  mem := Mem
-
-theorem mem_def {a : α} {as : Array α} : a ∈ as ↔ a ∈ as.toList :=
-  ⟨fun | .mk h => h, Array.Mem.mk⟩
-
-@[simp] theorem mem_toArray {a : α} {l : List α} : a ∈ l.toArray ↔ a ∈ l := by
-  simp [mem_def]
-
-@[simp] theorem getElem_mem {l : Array α} {i : Nat} (h : i < l.size) : l[i] ∈ l := by
-  rw [Array.mem_def, ← getElem_toList]
-  apply List.getElem_mem
-
-end Array
-
-namespace List
-
-@[simp] theorem toArray_toList (a : Array α) : a.toList.toArray = a := rfl
-
-@[simp] theorem getElem_toArray {a : List α} {i : Nat} (h : i < a.toArray.size) :
-    a.toArray[i] = a[i]'(by simpa using h) := rfl
-
-@[simp] theorem getElem?_toArray {a : List α} {i : Nat} : a.toArray[i]? = a[i]? := rfl
-
-@[simp] theorem getElem!_toArray [Inhabited α] {a : List α} {i : Nat} :
-    a.toArray[i]! = a[i]! := rfl
-
-end List
-
-namespace Array
-
 @[deprecated toList_toArray (since := "2024-09-09")] abbrev data_toArray := @toList_toArray
 
 @[deprecated Array.toList (since := "2024-09-10")] abbrev Array.data := @Array.toList
@@ -149,7 +103,7 @@ def uget (a : @& Array α) (i : USize) (h : i.toNat < a.size) : α :=
    `fset` may be slightly slower than `uset`. -/
 @[extern "lean_array_uset"]
 def uset (a : Array α) (i : USize) (v : α) (h : i.toNat < a.size) : Array α :=
-  a.set i.toNat v h
+  a.set ⟨i.toNat, h⟩ v
 
 @[extern "lean_array_pop"]
 def pop (a : Array α) : Array α where
@@ -171,15 +125,14 @@ This will perform the update destructively provided that `a` has a reference
 count of 1 when called.
 -/
 @[extern "lean_array_fswap"]
-def swap (a : Array α) (i j : @& Nat) (hi : i < a.size := by get_elem_tactic) (hj : j < a.size := by get_elem_tactic) : Array α :=
-  let v₁ := a[i]
-  let v₂ := a[j]
+def swap (a : Array α) (i j : @& Fin a.size) : Array α :=
+  let v₁ := a.get i
+  let v₂ := a.get j
   let a'  := a.set i v₂
-  a'.set j v₁ (Nat.lt_of_lt_of_eq hj (size_set a i v₂ _).symm)
+  a'.set (size_set a i v₂ ▸ j) v₁
 
-@[simp] theorem size_swap (a : Array α) (i j : Nat) {hi hj} : (a.swap i j hi hj).size = a.size := by
-  show ((a.set i a[j]).set j a[i]
-    (Nat.lt_of_lt_of_eq hj (size_set a i a[j] _).symm)).size = a.size
+@[simp] theorem size_swap (a : Array α) (i j : Fin a.size) : (a.swap i j).size = a.size := by
+  show ((a.set i (a.get j)).set (size_set a i _ ▸ j) (a.get i)).size = a.size
   rw [size_set, size_set]
 
 /--
@@ -189,14 +142,12 @@ This will perform the update destructively provided that `a` has a reference
 count of 1 when called.
 -/
 @[extern "lean_array_swap"]
-def swapIfInBounds (a : Array α) (i j : @& Nat) : Array α :=
+def swap! (a : Array α) (i j : @& Nat) : Array α :=
   if h₁ : i < a.size then
-  if h₂ : j < a.size then swap a i j
+  if h₂ : j < a.size then swap a ⟨i, h₁⟩ ⟨j, h₂⟩
   else a
   else a
 
-@[deprecated swapIfInBounds (since := "2024-11-24")] abbrev swap! := @swapIfInBounds
-
 /-! ### GetElem instance for `USize`, backed by `uget` -/
 
 instance : GetElem (Array α) USize α fun xs i => i.toNat < xs.size where
@@ -241,63 +192,60 @@ def ofFn {n} (f : Fin n → α) : Array α := go 0 (mkEmpty n) where
 
 /-- The array `#[0, 1, ..., n - 1]`. -/
 def range (n : Nat) : Array Nat :=
-  ofFn fun (i : Fin n) => i
+  n.fold (flip Array.push) (mkEmpty n)
 
 def singleton (v : α) : Array α :=
   mkArray 1 v
 
-def back! [Inhabited α] (a : Array α) : α :=
-  a[a.size - 1]!
-
-@[deprecated back! (since := "2024-10-31")] abbrev back := @back!
+def back [Inhabited α] (a : Array α) : α :=
+  a.get! (a.size - 1)
 
 def get? (a : Array α) (i : Nat) : Option α :=
   if h : i < a.size then some a[i] else none
 
 def back? (a : Array α) : Option α :=
-  a[a.size - 1]?
+  a.get? (a.size - 1)
 
-@[inline] def swapAt (a : Array α) (i : Nat) (v : α) (hi : i < a.size := by get_elem_tactic) : α × Array α :=
-  let e := a[i]
+@[inline] def swapAt (a : Array α) (i : Fin a.size) (v : α) : α × Array α :=
+  let e := a.get i
   let a := a.set i v
   (e, a)
 
 @[inline]
 def swapAt! (a : Array α) (i : Nat) (v : α) : α × Array α :=
   if h : i < a.size then
-    swapAt a i v
+    swapAt a ⟨i, h⟩ v
   else
-    have : Inhabited (α × Array α) := ⟨(v, a)⟩
+    have : Inhabited α := ⟨v⟩
     panic! ("index " ++ toString i ++ " out of bounds")
 
-/-- `take a n` returns the first `n` elements of `a`. -/
-def take (a : Array α) (n : Nat) : Array α :=
+def shrink (a : Array α) (n : Nat) : Array α :=
   let rec loop
     | 0,   a => a
     | n+1, a => loop n a.pop
   loop (a.size - n) a
 
-@[deprecated take (since := "2024-10-22")] abbrev shrink := @take
-
 @[inline]
 unsafe def modifyMUnsafe [Monad m] (a : Array α) (i : Nat) (f : α → m α) : m (Array α) := do
   if h : i < a.size then
-    let v                := a[i]
+    let idx : Fin a.size := ⟨i, h⟩
+    let v                := a.get idx
     -- Replace a[i] by `box(0)`.  This ensures that `v` remains unshared if possible.
     -- Note: we assume that arrays have a uniform representation irrespective
     -- of the element type, and that it is valid to store `box(0)` in any array.
-    let a'               := a.set i (unsafeCast ())
+    let a'               := a.set idx (unsafeCast ())
     let v ← f v
-    pure <| a'.set i v (Nat.lt_of_lt_of_eq h (size_set a ..).symm)
+    pure <| a'.set (size_set a .. ▸ idx) v
   else
     pure a
 
 @[implemented_by modifyMUnsafe]
 def modifyM [Monad m] (a : Array α) (i : Nat) (f : α → m α) : m (Array α) := do
   if h : i < a.size then
-    let v   := a[i]
+    let idx := ⟨i, h⟩
+    let v   := a.get idx
     let v ← f v
-    pure <| a.set i v
+    pure <| a.set idx v
   else
     pure a
 
@@ -313,21 +261,21 @@ def modifyOp (self : Array α) (idx : Nat) (f : α → α) : Array α :=
   We claim this unsafe implementation is correct because an array cannot have more than `usizeSz` elements in our runtime.
 
   This kind of low level trick can be removed with a little bit of compiler support. For example, if the compiler simplifies `as.size < usizeSz` to true. -/
-@[inline] unsafe def forIn'Unsafe {α : Type u} {β : Type v} {m : Type v → Type w} [Monad m] (as : Array α) (b : β) (f : (a : α) → a ∈ as → β → m (ForInStep β)) : m β :=
+@[inline] unsafe def forInUnsafe {α : Type u} {β : Type v} {m : Type v → Type w} [Monad m] (as : Array α) (b : β) (f : α → β → m (ForInStep β)) : m β :=
   let sz := as.usize
   let rec @[specialize] loop (i : USize) (b : β) : m β := do
     if i < sz then
       let a := as.uget i lcProof
-      match (← f a lcProof b) with
+      match (← f a b) with
       | ForInStep.done  b => pure b
       | ForInStep.yield b => loop (i+1) b
     else
       pure b
   loop 0 b
 
-/-- Reference implementation for `forIn'` -/
-@[implemented_by Array.forIn'Unsafe]
-protected def forIn' {α : Type u} {β : Type v} {m : Type v → Type w} [Monad m] (as : Array α) (b : β) (f : (a : α) → a ∈ as → β → m (ForInStep β)) : m β :=
+/-- Reference implementation for `forIn` -/
+@[implemented_by Array.forInUnsafe]
+protected def forIn {α : Type u} {β : Type v} {m : Type v → Type w} [Monad m] (as : Array α) (b : β) (f : α → β → m (ForInStep β)) : m β :=
   let rec loop (i : Nat) (h : i ≤ as.size) (b : β) : m β := do
     match i, h with
     | 0,   _ => pure b
@@ -335,17 +283,15 @@ protected def forIn' {α : Type u} {β : Type v} {m : Type v → Type w} [Monad
       have h' : i < as.size            := Nat.lt_of_lt_of_le (Nat.lt_succ_self i) h
       have : as.size - 1 < as.size     := Nat.sub_lt (Nat.zero_lt_of_lt h') (by decide)
       have : as.size - 1 - i < as.size := Nat.lt_of_le_of_lt (Nat.sub_le (as.size - 1) i) this
-      match (← f as[as.size - 1 - i] (getElem_mem this) b) with
+      match (← f as[as.size - 1 - i] b) with
       | ForInStep.done b  => pure b
       | ForInStep.yield b => loop i (Nat.le_of_lt h') b
   loop as.size (Nat.le_refl _) b
 
-instance : ForIn' m (Array α) α inferInstance where
-  forIn' := Array.forIn'
+instance : ForIn m (Array α) α where
+  forIn := Array.forIn
 
--- No separate `ForIn` instance is required because it can be derived from `ForIn'`.
-
-/-- See comment at `forIn'Unsafe` -/
+/-- See comment at `forInUnsafe` -/
 @[inline]
 unsafe def foldlMUnsafe {α : Type u} {β : Type v} {m : Type v → Type w} [Monad m] (f : β → α → m β) (init : β) (as : Array α) (start := 0) (stop := as.size) : m β :=
   let rec @[specialize] fold (i : USize) (stop : USize) (b : β) : m β := do
@@ -380,7 +326,7 @@ def foldlM {α : Type u} {β : Type v} {m : Type v → Type w} [Monad m] (f : β
   else
     fold as.size (Nat.le_refl _)
 
-/-- See comment at `forIn'Unsafe` -/
+/-- See comment at `forInUnsafe` -/
 @[inline]
 unsafe def foldrMUnsafe {α : Type u} {β : Type v} {m : Type v → Type w} [Monad m] (f : α → β → m β) (init : β) (as : Array α) (start := as.size) (stop := 0) : m β :=
   let rec @[specialize] fold (i : USize) (stop : USize) (b : β) : m β := do
@@ -419,7 +365,7 @@ def foldrM {α : Type u} {β : Type v} {m : Type v → Type w} [Monad m] (f : α
   else
     pure init
 
-/-- See comment at `forIn'Unsafe` -/
+/-- See comment at `forInUnsafe` -/
 @[inline]
 unsafe def mapMUnsafe {α : Type u} {β : Type v} {m : Type v → Type w} [Monad m] (f : α → m β) (as : Array α) : m (Array β) :=
   let sz := as.usize
@@ -450,48 +396,37 @@ def mapM {α : Type u} {β : Type v} {m : Type v → Type w} [Monad m] (f : α
   decreasing_by simp_wf; decreasing_trivial_pre_omega
   map 0 (mkEmpty as.size)
 
-@[deprecated mapM (since := "2024-11-11")] abbrev sequenceMap := @mapM
-
-/-- Variant of `mapIdxM` which receives the index as a `Fin as.size`. -/
 @[inline]
-def mapFinIdxM {α : Type u} {β : Type v} {m : Type v → Type w} [Monad m]
-    (as : Array α) (f : Fin as.size → α → m β) : m (Array β) :=
+def mapIdxM {α : Type u} {β : Type v} {m : Type v → Type w} [Monad m] (as : Array α) (f : Fin as.size → α → m β) : m (Array β) :=
   let rec @[specialize] map (i : Nat) (j : Nat) (inv : i + j = as.size) (bs : Array β) : m (Array β) := do
     match i, inv with
     | 0,    _  => pure bs
     | i+1, inv =>
-      have j_lt : j < as.size := by
+      have : j < as.size := by
         rw [← inv, Nat.add_assoc, Nat.add_comm 1 j, Nat.add_comm]
         apply Nat.le_add_right
+      let idx : Fin as.size := ⟨j, this⟩
       have : i + (j + 1) = as.size := by rw [← inv, Nat.add_comm j 1, Nat.add_assoc]
-      map i (j+1) this (bs.push (← f ⟨j, j_lt⟩ (as.get j j_lt)))
+      map i (j+1) this (bs.push (← f idx (as.get idx)))
   map as.size 0 rfl (mkEmpty as.size)
 
 @[inline]
-def mapIdxM {α : Type u} {β : Type v} {m : Type v → Type w} [Monad m] (f : Nat → α → m β) (as : Array α) : m (Array β) :=
-  as.mapFinIdxM fun i a => f i a
-
-@[inline]
-def findSomeM? {α : Type u} {β : Type v} {m : Type v → Type w} [Monad m] (f : α → m (Option β)) (as : Array α) : m (Option β) := do
+def findSomeM? {α : Type u} {β : Type v} {m : Type v → Type w} [Monad m] (as : Array α) (f : α → m (Option β)) : m (Option β) := do
   for a in as do
     match (← f a) with
     | some b => return b
     | _      => pure ⟨⟩
   return none
 
-/--
-Note that the universe level is contrained to `Type` here,
-to avoid having to have the predicate live in `p : α → m (ULift Bool)`.
--/
 @[inline]
-def findM? {α : Type} {m : Type → Type} [Monad m] (p : α → m Bool) (as : Array α) : m (Option α) := do
+def findM? {α : Type} {m : Type → Type} [Monad m] (as : Array α) (p : α → m Bool) : m (Option α) := do
   for a in as do
     if (← p a) then
       return a
   return none
 
 @[inline]
-def findIdxM? [Monad m] (p : α → m Bool) (as : Array α) : m (Option Nat) := do
+def findIdxM? [Monad m] (as : Array α) (p : α → m Bool) : m (Option Nat) := do
   let mut i := 0
   for a in as do
     if (← p a) then
@@ -543,7 +478,7 @@ def allM {α : Type u} {m : Type → Type w} [Monad m] (p : α → m Bool) (as :
   return !(← as.anyM (start := start) (stop := stop) fun v => return !(← p v))
 
 @[inline]
-def findSomeRevM? {α : Type u} {β : Type v} {m : Type v → Type w} [Monad m] (f : α → m (Option β)) (as : Array α) : m (Option β) :=
+def findSomeRevM? {α : Type u} {β : Type v} {m : Type v → Type w} [Monad m] (as : Array α) (f : α → m (Option β)) : m (Option β) :=
   let rec @[specialize] find : (i : Nat) → i ≤ as.size → m (Option β)
     | 0,   _ => pure none
     | i+1, h => do
@@ -557,7 +492,7 @@ def findSomeRevM? {α : Type u} {β : Type v} {m : Type v → Type w} [Monad m]
   find as.size (Nat.le_refl _)
 
 @[inline]
-def findRevM? {α : Type} {m : Type → Type w} [Monad m] (p : α → m Bool) (as : Array α) : m (Option α) :=
+def findRevM? {α : Type} {m : Type → Type w} [Monad m] (as : Array α) (p : α → m Bool) : m (Option α) :=
   as.findSomeRevM? fun a => return if (← p a) then some a else none
 
 @[inline]
@@ -580,13 +515,8 @@ def foldr {α : Type u} {β : Type v} (f : α → β → β) (init : β) (as : A
 def map {α : Type u} {β : Type v} (f : α → β) (as : Array α) : Array β :=
   Id.run <| as.mapM f
 
-/-- Variant of `mapIdx` which receives the index as a `Fin as.size`. -/
 @[inline]
-def mapFinIdx {α : Type u} {β : Type v} (as : Array α) (f : Fin as.size → α → β) : Array β :=
-  Id.run <| as.mapFinIdxM f
-
-@[inline]
-def mapIdx {α : Type u} {β : Type v} (f : Nat → α → β) (as : Array α) : Array β :=
+def mapIdx {α : Type u} {β : Type v} (as : Array α) (f : Fin as.size → α → β) : Array β :=
   Id.run <| as.mapIdxM f
 
 /-- Turns `#[a, b]` into `#[(a, 0), (b, 1)]`. -/
@@ -594,33 +524,29 @@ def zipWithIndex (arr : Array α) : Array (α × Nat) :=
   arr.mapIdx fun i a => (a, i)
 
 @[inline]
-def find? {α : Type u} (p : α → Bool) (as : Array α) : Option α :=
-  Id.run do
-    for a in as do
-      if p a then
-        return a
-    return none
+def find? {α : Type} (as : Array α) (p : α → Bool) : Option α :=
+  Id.run <| as.findM? p
 
 @[inline]
-def findSome? {α : Type u} {β : Type v} (f : α → Option β) (as : Array α) : Option β :=
+def findSome? {α : Type u} {β : Type v} (as : Array α) (f : α → Option β) : Option β :=
   Id.run <| as.findSomeM? f
 
 @[inline]
-def findSome! {α : Type u} {β : Type v} [Inhabited β] (f : α → Option β) (a : Array α) : β :=
-  match a.findSome? f with
+def findSome! {α : Type u} {β : Type v} [Inhabited β] (a : Array α) (f : α → Option β) : β :=
+  match findSome? a f with
   | some b => b
   | none   => panic! "failed to find element"
 
 @[inline]
-def findSomeRev? {α : Type u} {β : Type v} (f : α → Option β) (as : Array α) : Option β :=
+def findSomeRev? {α : Type u} {β : Type v} (as : Array α) (f : α → Option β) : Option β :=
   Id.run <| as.findSomeRevM? f
 
 @[inline]
-def findRev? {α : Type} (p : α → Bool) (as : Array α) : Option α :=
+def findRev? {α : Type} (as : Array α) (p : α → Bool) : Option α :=
   Id.run <| as.findRevM? p
 
 @[inline]
-def findIdx? {α : Type u} (p : α → Bool) (as : Array α) : Option Nat :=
+def findIdx? {α : Type u} (as : Array α) (p : α → Bool) : Option Nat :=
   let rec @[semireducible] -- This is otherwise irreducible because it uses well-founded recursion.
   loop (j : Nat) :=
     if h : j < as.size then
@@ -629,20 +555,14 @@ def findIdx? {α : Type u} (p : α → Bool) (as : Array α) : Option Nat :=
     decreasing_by simp_wf; decreasing_trivial_pre_omega
   loop 0
 
-@[inline]
-def findFinIdx? {α : Type u} (p : α → Bool) (as : Array α) : Option (Fin as.size) :=
-  let rec @[semireducible] -- This is otherwise irreducible because it uses well-founded recursion.
-  loop (j : Nat) :=
-    if h : j < as.size then
-      if p as[j] then some ⟨j, h⟩ else loop (j + 1)
-    else none
-    decreasing_by simp_wf; decreasing_trivial_pre_omega
-  loop 0
+def getIdx? [BEq α] (a : Array α) (v : α) : Option Nat :=
+  a.findIdx? fun a => a == v
 
 @[semireducible] -- This is otherwise irreducible because it uses well-founded recursion.
 def indexOfAux [BEq α] (a : Array α) (v : α) (i : Nat) : Option (Fin a.size) :=
   if h : i < a.size then
-    if a[i] == v then some ⟨i, h⟩
+    let idx : Fin a.size := ⟨i, h⟩;
+    if a.get idx == v then some idx
     else indexOfAux a v (i+1)
   else none
 decreasing_by simp_wf; decreasing_trivial_pre_omega
@@ -650,10 +570,6 @@ decreasing_by simp_wf; decreasing_trivial_pre_omega
 def indexOf? [BEq α] (a : Array α) (v : α) : Option (Fin a.size) :=
   indexOfAux a v 0
 
-@[deprecated indexOf? (since := "2024-11-20")]
-def getIdx? [BEq α] (a : Array α) (v : α) : Option Nat :=
-  a.findIdx? fun a => a == v
-
 @[inline]
 def any (as : Array α) (p : α → Bool) (start := 0) (stop := as.size) : Bool :=
   Id.run <| as.anyM p start stop
@@ -663,7 +579,7 @@ def all (as : Array α) (p : α → Bool) (start := 0) (stop := as.size) : Bool
   Id.run <| as.allM p start stop
 
 def contains [BEq α] (as : Array α) (a : α) : Bool :=
-  as.any (a == ·)
+  as.any (· == a)
 
 def elem [BEq α] (a : α) (as : Array α) : Bool :=
   as.contains a
@@ -691,22 +607,18 @@ protected def appendList (as : Array α) (bs : List α) : Array α :=
 instance : HAppend (Array α) (List α) (Array α) := ⟨Array.appendList⟩
 
 @[inline]
-def flatMapM [Monad m] (f : α → m (Array β)) (as : Array α) : m (Array β) :=
+def concatMapM [Monad m] (f : α → m (Array β)) (as : Array α) : m (Array β) :=
   as.foldlM (init := empty) fun bs a => do return bs ++ (← f a)
 
-@[deprecated flatMapM (since := "2024-10-16")] abbrev concatMapM := @flatMapM
-
 @[inline]
-def flatMap (f : α → Array β) (as : Array α) : Array β :=
+def concatMap (f : α → Array β) (as : Array α) : Array β :=
   as.foldl (init := empty) fun bs a => bs ++ f a
 
-@[deprecated flatMap (since := "2024-10-16")] abbrev concatMap := @flatMap
-
 /-- Joins array of array into a single array.
 
 `flatten #[#[a₁, a₂, ⋯], #[b₁, b₂, ⋯], ⋯]` = `#[a₁, a₂, ⋯, b₁, b₂, ⋯]`
 -/
-@[inline] def flatten (as : Array (Array α)) : Array α :=
+def flatten (as : Array (Array α)) : Array α :=
   as.foldl (init := empty) fun r a => r ++ a
 
 @[inline]
@@ -762,7 +674,7 @@ where
   loop (as : Array α) (i : Nat) (j : Fin as.size) :=
     if h : i < j then
       have := termination h
-      let as := as.swap i j (Nat.lt_trans h j.2)
+      let as := as.swap ⟨i, Nat.lt_trans h j.2⟩ j
       have : j-1 < as.size := by rw [size_swap]; exact Nat.lt_of_le_of_lt (Nat.pred_le _) j.2
       loop as (i+1) ⟨j-1, this⟩
     else
@@ -771,7 +683,7 @@ where
 @[semireducible] -- This is otherwise irreducible because it uses well-founded recursion.
 def popWhile (p : α → Bool) (as : Array α) : Array α :=
   if h : as.size > 0 then
-    if p (as[as.size - 1]'(Nat.sub_lt h (by decide))) then
+    if p (as.get ⟨as.size - 1, Nat.sub_lt h (by decide)⟩) then
       popWhile p as.pop
     else
       as
@@ -783,7 +695,7 @@ def takeWhile (p : α → Bool) (as : Array α) : Array α :=
   let rec @[semireducible] -- This is otherwise irreducible because it uses well-founded recursion.
   go (i : Nat) (r : Array α) : Array α :=
     if h : i < as.size then
-      let a := as[i]
+      let a := as.get ⟨i, h⟩
       if p a then
         go (i+1) (r.push a)
       else
@@ -793,63 +705,49 @@ def takeWhile (p : α → Bool) (as : Array α) : Array α :=
     decreasing_by simp_wf; decreasing_trivial_pre_omega
   go 0 #[]
 
-/--
-Remove the element at a given index from an array without a runtime bounds checks,
-using a `Nat` index and a tactic-provided bound.
+/-- Remove the element at a given index from an array without bounds checks, using a `Fin` index.
 
-This function takes worst case O(n) time because
-it has to backshift all elements at positions greater than `i`.-/
+  This function takes worst case O(n) time because
+  it has to backshift all elements at positions greater than `i`.-/
 @[semireducible] -- This is otherwise irreducible because it uses well-founded recursion.
-def eraseIdx (a : Array α) (i : Nat) (h : i < a.size := by get_elem_tactic) : Array α :=
-  if h' : i + 1 < a.size then
-    let a' := a.swap (i + 1) i
-    a'.eraseIdx (i + 1) (by simp [a', h'])
+def feraseIdx (a : Array α) (i : Fin a.size) : Array α :=
+  if h : i.val + 1 < a.size then
+    let a' := a.swap ⟨i.val + 1, h⟩ i
+    let i' : Fin a'.size := ⟨i.val + 1, by simp [a', h]⟩
+    a'.feraseIdx i'
   else
     a.pop
-termination_by a.size - i
-decreasing_by simp_wf; exact Nat.sub_succ_lt_self _ _ h
+termination_by a.size - i.val
+decreasing_by simp_wf; exact Nat.sub_succ_lt_self _ _ i.isLt
 
 -- This is required in `Lean.Data.PersistentHashMap`.
-@[simp] theorem size_eraseIdx (a : Array α) (i : Nat) (h) : (a.eraseIdx i h).size = a.size - 1 := by
-  induction a, i, h using Array.eraseIdx.induct with
-  | @case1 a i h h' a' ih =>
-    unfold eraseIdx
-    simp [h', a', ih]
-  | case2 a i h h' =>
-    unfold eraseIdx
-    simp [h']
+theorem size_feraseIdx (a : Array α) (i : Fin a.size) : (a.feraseIdx i).size = a.size - 1 := by
+  induction a, i using Array.feraseIdx.induct with
+  | @case1 a i h a' _ ih =>
+    unfold feraseIdx
+    simp [h, a', ih]
+  | case2 a i h =>
+    unfold feraseIdx
+    simp [h]
 
 /-- Remove the element at a given index from an array, or do nothing if the index is out of bounds.
 
   This function takes worst case O(n) time because
   it has to backshift all elements at positions greater than `i`.-/
-def eraseIdxIfInBounds (a : Array α) (i : Nat) : Array α :=
-  if h : i < a.size then a.eraseIdx i h else a
-
-/-- Remove the element at a given index from an array, or panic if the index is out of bounds.
-
-This function takes worst case O(n) time because
-it has to backshift all elements at positions greater than `i`. -/
-def eraseIdx! (a : Array α) (i : Nat) : Array α :=
-  if h : i < a.size then a.eraseIdx i h else panic! "invalid index"
+def eraseIdx (a : Array α) (i : Nat) : Array α :=
+  if h : i < a.size then a.feraseIdx ⟨i, h⟩ else a
 
 def erase [BEq α] (as : Array α) (a : α) : Array α :=
   match as.indexOf? a with
   | none   => as
-  | some i => as.eraseIdx i
-
-/-- Erase the first element that satisfies the predicate `p`. -/
-def eraseP (as : Array α) (p : α → Bool) : Array α :=
-  match as.findIdx? p with
-  | none   => as
-  | some i => as.eraseIdxIfInBounds i
+  | some i => as.feraseIdx i
 
 /-- Insert element `a` at position `i`. -/
-@[inline] def insertIdx (as : Array α) (i : Nat) (a : α) (_ : i ≤ as.size := by get_elem_tactic) : Array α :=
+@[inline] def insertAt (as : Array α) (i : Fin (as.size + 1)) (a : α) : Array α :=
   let rec @[semireducible] -- This is otherwise irreducible because it uses well-founded recursion.
   loop (as : Array α) (j : Fin as.size) :=
-    if i < j then
-      let j' : Fin as.size := ⟨j-1, Nat.lt_of_le_of_lt (Nat.pred_le _) j.2⟩
+    if i.1 < j then
+      let j' := ⟨j-1, Nat.lt_of_le_of_lt (Nat.pred_le _) j.2⟩
       let as := as.swap j' j
       loop as ⟨j', by rw [size_swap]; exact j'.2⟩
     else
@@ -859,23 +757,12 @@ def eraseP (as : Array α) (p : α → Bool) : Array α :=
   let as := as.push a
   loop as ⟨j, size_push .. ▸ j.lt_succ_self⟩
 
-@[deprecated insertIdx (since := "2024-11-20")] abbrev insertAt := @insertIdx
-
 /-- Insert element `a` at position `i`. Panics if `i` is not `i ≤ as.size`. -/
-def insertIdx! (as : Array α) (i : Nat) (a : α) : Array α :=
+def insertAt! (as : Array α) (i : Nat) (a : α) : Array α :=
   if h : i ≤ as.size then
-    insertIdx as i a
+    insertAt as ⟨i, Nat.lt_succ_of_le h⟩ a
   else panic! "invalid index"
 
-@[deprecated insertIdx! (since := "2024-11-20")] abbrev insertAt! := @insertIdx!
-
-/-- Insert element `a` at position `i`, or do nothing if `as.size < i`. -/
-def insertIdxIfInBounds (as : Array α) (i : Nat) (a : α) : Array α :=
-  if h : i ≤ as.size then
-    insertIdx as i a
-  else
-    as
-
 @[semireducible] -- This is otherwise irreducible because it uses well-founded recursion.
 def isPrefixOfAux [BEq α] (as bs : Array α) (hle : as.size ≤ bs.size) (i : Nat) : Bool :=
   if h : i < as.size then
@@ -899,12 +786,12 @@ def isPrefixOf [BEq α] (as bs : Array α) : Bool :=
     false
 
 @[semireducible, specialize] -- This is otherwise irreducible because it uses well-founded recursion.
-def zipWithAux (as : Array α) (bs : Array β) (f : α → β → γ) (i : Nat) (cs : Array γ) : Array γ :=
+def zipWithAux (f : α → β → γ) (as : Array α) (bs : Array β) (i : Nat) (cs : Array γ) : Array γ :=
   if h : i < as.size then
     let a := as[i]
     if h : i < bs.size then
       let b := bs[i]
-      zipWithAux as bs f (i+1) <| cs.push <| f a b
+      zipWithAux f as bs (i+1) <| cs.push <| f a b
     else
       cs
   else
@@ -912,58 +799,23 @@ def zipWithAux (as : Array α) (bs : Array β) (f : α → β → γ) (i : Nat)
 decreasing_by simp_wf; decreasing_trivial_pre_omega
 
 @[inline] def zipWith (as : Array α) (bs : Array β) (f : α → β → γ) : Array γ :=
-  zipWithAux as bs f 0 #[]
+  zipWithAux f as bs 0 #[]
 
 def zip (as : Array α) (bs : Array β) : Array (α × β) :=
   zipWith as bs Prod.mk
 
-def zipWithAll (as : Array α) (bs : Array β) (f : Option α → Option β → γ) : Array γ :=
-  go as bs 0 #[]
-where go (as : Array α) (bs : Array β) (i : Nat) (cs : Array γ) :=
-  if i < max as.size bs.size then
-    let a := as[i]?
-    let b := bs[i]?
-    go as bs (i+1) (cs.push (f a b))
-  else
-    cs
-  termination_by max as.size bs.size - i
-  decreasing_by simp_wf; decreasing_trivial_pre_omega
-
 def unzip (as : Array (α × β)) : Array α × Array β :=
   as.foldl (init := (#[], #[])) fun (as, bs) (a, b) => (as.push a, bs.push b)
 
-@[deprecated partition (since := "2024-11-06")]
 def split (as : Array α) (p : α → Bool) : Array α × Array α :=
   as.foldl (init := (#[], #[])) fun (as, bs) a =>
     if p a then (as.push a, bs) else (as, bs.push a)
 
-/-! ## Auxiliary functions used in metaprogramming.
+/-! ### Auxiliary functions used in metaprogramming.
 
-We do not currently intend to provide verification theorems for these functions.
+We do not intend to provide verification theorems for these functions.
 -/
 
-/- ### reduceOption -/
-
-/-- Drop `none`s from a Array, and replace each remaining `some a` with `a`. -/
-@[inline] def reduceOption (as : Array (Option α)) : Array α :=
-  as.filterMap id
-
-/-! ### eraseReps -/
-
-/--
-`O(|l|)`. Erase repeated adjacent elements. Keeps the first occurrence of each run.
-* `eraseReps #[1, 3, 2, 2, 2, 3, 5] = #[1, 3, 2, 3, 5]`
--/
-def eraseReps {α} [BEq α] (as : Array α) : Array α :=
-  if h : 0 < as.size then
-    let ⟨last, r⟩ := as.foldl (init := (as[0], #[])) fun ⟨last, r⟩ a =>
-      if a == last then ⟨last, r⟩ else ⟨a, r.push last⟩
-    r.push last
-  else
-    #[]
-
-/-! ### allDiff -/
-
 private def allDiffAuxAux [BEq α] (as : Array α) (a : α) : forall (i : Nat), i < as.size → Bool
   | 0,   _ => true
   | i+1, h =>
@@ -981,8 +833,6 @@ decreasing_by simp_wf; decreasing_trivial_pre_omega
 def allDiff [BEq α] (as : Array α) : Bool :=
   allDiffAux as 0
 
-/-! ### getEvenElems -/
-
 @[inline] def getEvenElems (as : Array α) : Array α :=
   (·.2) <| as.foldl (init := (true, Array.empty)) fun (even, r) a =>
     if even then

src/Init/Data/Array/BasicAux.lean

@@ -9,7 +9,7 @@ import Init.Data.Nat.Linear
 import Init.NotationExtra
 
 theorem Array.of_push_eq_push {as bs : Array α} (h : as.push a = bs.push b) : as = bs ∧ a = b := by
-  simp only [push, mk.injEq] at h
+  simp only [push, List.toArray_inj] at h
   have ⟨h₁, h₂⟩ := List.of_concat_eq_concat h
   cases as; cases bs
   simp_all
@@ -34,7 +34,7 @@ private theorem List.of_toArrayAux_eq_toArrayAux {as bs : List α} {cs ds : Arra
 
 @[simp] theorem List.toArray_eq_toArray_eq (as bs : List α) : (as.toArray = bs.toArray) = (as = bs) := by
   apply propext; apply Iff.intro
-  · intro h; simpa [toArray] using h
+  · intro h; simp [toArray] at h; have := of_toArrayAux_eq_toArrayAux h rfl; exact this.1
   · intro h; rw [h]
 
 def Array.mapM' [Monad m] (f : α → m β) (as : Array α) : m { bs : Array β // bs.size = as.size } :=
@@ -60,7 +60,7 @@ where
       if ptrEq a b then
         go (i+1) as
       else
-        go (i+1) (as.set i b h)
+        go (i+1) (as.set ⟨i, h⟩ b)
     else
       return as
 

src/Init/Data/Array/BinSearch.lean

@@ -5,64 +5,59 @@ Authors: Leonardo de Moura
 -/
 prelude
 import Init.Data.Array.Basic
-import Init.Omega
 universe u v
 
-namespace Array
+-- TODO: CLEANUP
 
-@[specialize] def binSearchAux {α : Type u} {β : Type v} (lt : α → α → Bool) (found : Option α → β) (as : Array α) (k : α) :
-    (lo : Fin (as.size + 1)) → (hi : Fin as.size) → (lo.1 ≤ hi.1) → β
-  | lo, hi, h =>
-    let m := (lo.1 + hi.1)/2
-    let a := as[m]
-    if lt a k then
-      if h' : m + 1 ≤ hi.1 then
-        binSearchAux lt found as k ⟨m+1, by omega⟩ hi h'
-      else found none
-    else if lt k a then
-      if h' : m = 0 ∨ m - 1 < lo.1 then found none
-      else binSearchAux lt found as k lo ⟨m-1, by omega⟩ (by simp; omega)
-    else found (some a)
-termination_by lo hi => hi.1 - lo.1
+namespace Array
+-- TODO: remove the [Inhabited α] parameters as soon as we have the tactic framework for automating proof generation and using Array.fget
+-- TODO: remove `partial` using well-founded recursion
+
+@[specialize] partial def binSearchAux {α : Type u} {β : Type v} [Inhabited β] (lt : α → α → Bool) (found : Option α → β) (as : Array α) (k : α) : Nat → Nat → β
+  | lo, hi =>
+    if lo <= hi then
+      let _ := Inhabited.mk k
+      let m := (lo + hi)/2
+      let a := as.get! m
+      if lt a k then binSearchAux lt found as k (m+1) hi
+      else if lt k a then
+        if m == 0 then found none
+        else binSearchAux lt found as k lo (m-1)
+      else found (some a)
+    else found none
 
 @[inline] def binSearch {α : Type} (as : Array α) (k : α) (lt : α → α → Bool) (lo := 0) (hi := as.size - 1) : Option α :=
-  if h : lo < as.size then
+  if lo < as.size then
     let hi := if hi < as.size then hi else as.size - 1
-    if w : lo ≤ hi then
-      binSearchAux lt id as k ⟨lo, by omega⟩ ⟨hi, by simp [hi]; split <;> omega⟩ (by simp [hi]; omega)
-    else
-      none
+    binSearchAux lt id as k lo hi
   else
     none
 
 @[inline] def binSearchContains {α : Type} (as : Array α) (k : α) (lt : α → α → Bool) (lo := 0) (hi := as.size - 1) : Bool :=
-  if h : lo < as.size then
+  if lo < as.size then
     let hi := if hi < as.size then hi else as.size - 1
-    if w : lo ≤ hi then
-      binSearchAux lt Option.isSome as k ⟨lo, by omega⟩ ⟨hi, by simp [hi]; split <;> omega⟩ (by simp [hi]; omega)
-    else
-      false
+    binSearchAux lt Option.isSome as k lo hi
   else
     false
 
-@[specialize] private def binInsertAux {α : Type u} {m : Type u → Type v} [Monad m]
+@[specialize] private partial def binInsertAux {α : Type u} {m : Type u → Type v} [Monad m]
     (lt : α → α → Bool)
     (merge : α → m α)
     (add : Unit → m α)
     (as : Array α)
-    (k : α) : (lo : Fin as.size) → (hi : Fin as.size) → (lo.1 ≤ hi.1) → (lt as[lo] k) → m (Array α)
-  | lo, hi, h, w =>
-    let mid    := (lo.1 + hi.1)/2
-    let midVal := as[mid]
-    if w₁ : lt midVal k then
-      if h' : mid = lo then do let v ← add (); pure <| as.insertIdx (lo+1) v
-      else binInsertAux lt merge add as k ⟨mid, by omega⟩ hi (by simp; omega) w₁
-    else if w₂ : lt k midVal then
-      have : mid ≠ lo := fun z => by simp [midVal, z] at w₁; simp_all
-      binInsertAux lt merge add as k lo ⟨mid, by omega⟩ (by simp; omega) w
+    (k : α) : Nat → Nat → m (Array α)
+  | lo, hi =>
+    let _ := Inhabited.mk k
+    -- as[lo] < k < as[hi]
+    let mid    := (lo + hi)/2
+    let midVal := as.get! mid
+    if lt midVal k then
+      if mid == lo then do let v ← add (); pure <| as.insertAt! (lo+1) v
+      else binInsertAux lt merge add as k mid hi
+    else if lt k midVal then
+      binInsertAux lt merge add as k lo mid
     else do
       as.modifyM mid <| fun v => merge v
-termination_by lo hi => hi.1 - lo.1
 
 @[specialize] def binInsertM {α : Type u} {m : Type u → Type v} [Monad m]
     (lt : α → α → Bool)
@@ -70,12 +65,13 @@ termination_by lo hi => hi.1 - lo.1
     (add : Unit → m α)
     (as : Array α)
     (k : α) : m (Array α) :=
-  if h : as.size = 0 then do let v ← add (); pure <| as.push v
-  else if lt k as[0] then do let v ← add (); pure <| as.insertIdx 0 v
-  else if h' : !lt as[0] k then as.modifyM 0 <| merge
-  else if lt as[as.size - 1] k then do let v ← add (); pure <| as.push v
-  else if !lt k as[as.size - 1] then as.modifyM (as.size - 1) <| merge
-  else binInsertAux lt merge add as k ⟨0, by omega⟩ ⟨as.size - 1, by omega⟩ (by simp) (by simpa using h')
+  let _ := Inhabited.mk k
+  if as.isEmpty then do let v ← add (); pure <| as.push v
+  else if lt k (as.get! 0) then do let v ← add (); pure <| as.insertAt! 0 v
+  else if !lt (as.get! 0) k then as.modifyM 0 <| merge
+  else if lt as.back k then do let v ← add (); pure <| as.push v
+  else if !lt k as.back then as.modifyM (as.size - 1) <| merge
+  else binInsertAux lt merge add as k 0 (as.size - 1)
 
 @[inline] def binInsert {α : Type u} (lt : α → α → Bool) (as : Array α) (k : α) : Array α :=
   Id.run <| binInsertM lt (fun _ => k) (fun _ => k) as k

src/Init/Data/Array/Bootstrap.lean

@@ -15,26 +15,26 @@ This file contains some theorems about `Array` and `List` needed for `Init.Data.
 
 namespace Array
 
-theorem foldlM_toList.aux [Monad m]
+theorem foldlM_eq_foldlM_toList.aux [Monad m]
     (f : β → α → m β) (arr : Array α) (i j) (H : arr.size ≤ i + j) (b) :
     foldlM.loop f arr arr.size (Nat.le_refl _) i j b = (arr.toList.drop j).foldlM f b := by
   unfold foldlM.loop
   split; split
   · cases Nat.not_le_of_gt ‹_› (Nat.zero_add _ ▸ H)
   · rename_i i; rw [Nat.succ_add] at H
-    simp [foldlM_toList.aux f arr i (j+1) H]
-    rw (occs := [2]) [← List.getElem_cons_drop_succ_eq_drop ‹_›]
+    simp [foldlM_eq_foldlM_toList.aux f arr i (j+1) H]
+    rw (config := {occs := .pos [2]}) [← List.get_drop_eq_drop _ _ ‹_›]
     rfl
   · rw [List.drop_of_length_le (Nat.ge_of_not_lt ‹_›)]; rfl
 
-@[simp] theorem foldlM_toList [Monad m]
+theorem foldlM_eq_foldlM_toList [Monad m]
     (f : β → α → m β) (init : β) (arr : Array α) :
-    arr.toList.foldlM f init = arr.foldlM f init := by
-  simp [foldlM, foldlM_toList.aux]
+    arr.foldlM f init = arr.toList.foldlM f init := by
+  simp [foldlM, foldlM_eq_foldlM_toList.aux]
 
-@[simp] theorem foldl_toList (f : β → α → β) (init : β) (arr : Array α) :
-    arr.toList.foldl f init = arr.foldl f init :=
-  List.foldl_eq_foldlM .. ▸ foldlM_toList ..
+theorem foldl_eq_foldl_toList (f : β → α → β) (init : β) (arr : Array α) :
+    arr.foldl f init = arr.toList.foldl f init :=
+  List.foldl_eq_foldlM .. ▸ foldlM_eq_foldlM_toList ..
 
 theorem foldrM_eq_reverse_foldlM_toList.aux [Monad m]
     (f : α → β → m β) (arr : Array α) (init : β) (i h) :
@@ -42,7 +42,7 @@ theorem foldrM_eq_reverse_foldlM_toList.aux [Monad m]
   unfold foldrM.fold
   match i with
   | 0 => simp [List.foldlM, List.take]
-  | i+1 => rw [← List.take_concat_get _ _ h]; simp [← (aux f arr · i)]
+  | i+1 => rw [← List.take_concat_get _ _ h]; simp [← (aux f arr · i)]; rfl
 
 theorem foldrM_eq_reverse_foldlM_toList [Monad m] (f : α → β → m β) (init : β) (arr : Array α) :
     arr.foldrM f init = arr.toList.reverse.foldlM (fun x y => f y x) init := by
@@ -51,45 +51,34 @@ theorem foldrM_eq_reverse_foldlM_toList [Monad m] (f : α → β → m β) (init
   match arr, this with | _, .inl rfl => rfl | arr, .inr h => ?_
   simp [foldrM, h, ← foldrM_eq_reverse_foldlM_toList.aux, List.take_length]
 
-@[simp] theorem foldrM_toList [Monad m]
+theorem foldrM_eq_foldrM_toList [Monad m]
     (f : α → β → m β) (init : β) (arr : Array α) :
-    arr.toList.foldrM f init = arr.foldrM f init := by
+    arr.foldrM f init = arr.toList.foldrM f init := by
   rw [foldrM_eq_reverse_foldlM_toList, List.foldlM_reverse]
 
-@[simp] theorem foldr_toList (f : α → β → β) (init : β) (arr : Array α) :
-    arr.toList.foldr f init = arr.foldr f init :=
-  List.foldr_eq_foldrM .. ▸ foldrM_toList ..
+theorem foldr_eq_foldr_toList (f : α → β → β) (init : β) (arr : Array α) :
+    arr.foldr f init = arr.toList.foldr f init :=
+  List.foldr_eq_foldrM .. ▸ foldrM_eq_foldrM_toList ..
 
 @[simp] theorem push_toList (arr : Array α) (a : α) : (arr.push a).toList = arr.toList ++ [a] := by
   simp [push, List.concat_eq_append]
 
 @[simp] theorem toListAppend_eq (arr : Array α) (l) : arr.toListAppend l = arr.toList ++ l := by
-  simp [toListAppend, ← foldr_toList]
+  simp [toListAppend, foldr_eq_foldr_toList]
 
 @[simp] theorem toListImpl_eq (arr : Array α) : arr.toListImpl = arr.toList := by
-  simp [toListImpl, ← foldr_toList]
+  simp [toListImpl, foldr_eq_foldr_toList]
 
 @[simp] theorem pop_toList (arr : Array α) : arr.pop.toList = arr.toList.dropLast := rfl
 
 @[simp] theorem append_eq_append (arr arr' : Array α) : arr.append arr' = arr ++ arr' := rfl
 
-@[simp] theorem toList_append (arr arr' : Array α) :
+@[simp] theorem append_toList (arr arr' : Array α) :
     (arr ++ arr').toList = arr.toList ++ arr'.toList := by
   rw [← append_eq_append]; unfold Array.append
-  rw [← foldl_toList]
+  rw [foldl_eq_foldl_toList]
   induction arr'.toList generalizing arr <;> simp [*]
 
-@[simp] theorem toList_empty : (#[] : Array α).toList = [] := rfl
-
-@[simp] theorem append_nil (as : Array α) : as ++ #[] = as := by
-  apply ext'; simp only [toList_append, toList_empty, List.append_nil]
-
-@[simp] theorem nil_append (as : Array α) : #[] ++ as = as := by
-  apply ext'; simp only [toList_append, toList_empty, List.nil_append]
-
-@[simp] theorem append_assoc (as bs cs : Array α) : as ++ bs ++ cs = as ++ (bs ++ cs) := by
-  apply ext'; simp only [toList_append, List.append_assoc]
-
 @[simp] theorem appendList_eq_append
     (arr : Array α) (l : List α) : arr.appendList l = arr ++ l := rfl
 
@@ -98,44 +87,20 @@ theorem foldrM_eq_reverse_foldlM_toList [Monad m] (f : α → β → m β) (init
   rw [← appendList_eq_append]; unfold Array.appendList
   induction l generalizing arr <;> simp [*]
 
-@[deprecated "Use the reverse direction of `foldrM_toList`." (since := "2024-11-13")]
-theorem foldrM_eq_foldrM_toList [Monad m]
-    (f : α → β → m β) (init : β) (arr : Array α) :
-    arr.foldrM f init = arr.toList.foldrM f init := by
-  simp
+@[deprecated foldlM_eq_foldlM_toList (since := "2024-09-09")]
+abbrev foldlM_eq_foldlM_data := @foldlM_eq_foldlM_toList
 
-@[deprecated "Use the reverse direction of `foldlM_toList`." (since := "2024-11-13")]
-theorem foldlM_eq_foldlM_toList [Monad m]
-    (f : β → α → m β) (init : β) (arr : Array α) :
-    arr.foldlM f init = arr.toList.foldlM f init:= by
-  simp
-
-@[deprecated "Use the reverse direction of `foldr_toList`." (since := "2024-11-13")]
-theorem foldr_eq_foldr_toList
-    (f : α → β → β) (init : β) (arr : Array α) :
-    arr.foldr f init = arr.toList.foldr f init := by
-  simp
-
-@[deprecated "Use the reverse direction of `foldl_toList`." (since := "2024-11-13")]
-theorem foldl_eq_foldl_toList
-    (f : β → α → β) (init : β) (arr : Array α) :
-    arr.foldl f init = arr.toList.foldl f init:= by
-  simp
-
-@[deprecated foldlM_toList (since := "2024-09-09")]
-abbrev foldlM_eq_foldlM_data := @foldlM_toList
-
-@[deprecated foldl_toList (since := "2024-09-09")]
-abbrev foldl_eq_foldl_data := @foldl_toList
+@[deprecated foldl_eq_foldl_toList (since := "2024-09-09")]
+abbrev foldl_eq_foldl_data := @foldl_eq_foldl_toList
 
 @[deprecated foldrM_eq_reverse_foldlM_toList (since := "2024-09-09")]
 abbrev foldrM_eq_reverse_foldlM_data := @foldrM_eq_reverse_foldlM_toList
 
-@[deprecated foldrM_toList (since := "2024-09-09")]
-abbrev foldrM_eq_foldrM_data := @foldrM_toList
+@[deprecated foldrM_eq_foldrM_toList (since := "2024-09-09")]
+abbrev foldrM_eq_foldrM_data := @foldrM_eq_foldrM_toList
 
-@[deprecated foldr_toList (since := "2024-09-09")]
-abbrev foldr_eq_foldr_data := @foldr_toList
+@[deprecated foldr_eq_foldr_toList (since := "2024-09-09")]
+abbrev foldr_eq_foldr_data := @foldr_eq_foldr_toList
 
 @[deprecated push_toList (since := "2024-09-09")]
 abbrev push_data := @push_toList
@@ -146,8 +111,8 @@ abbrev toList_eq := @toListImpl_eq
 @[deprecated pop_toList (since := "2024-09-09")]
 abbrev pop_data := @pop_toList
 
-@[deprecated toList_append (since := "2024-09-09")]
-abbrev append_data := @toList_append
+@[deprecated append_toList (since := "2024-09-09")]
+abbrev append_data := @append_toList
 
 @[deprecated appendList_toList (since := "2024-09-09")]
 abbrev appendList_data := @appendList_toList

src/Init/Data/Array/DecidableEq.lean

@@ -6,15 +6,14 @@ Authors: Leonardo de Moura
 prelude
 import Init.Data.Array.Basic
 import Init.Data.BEq
-import Init.Data.List.Nat.BEq
 import Init.ByCases
 
 namespace Array
 
 theorem rel_of_isEqvAux
-    {r : α → α → Bool} {a b : Array α} (hsz : a.size = b.size) {i : Nat} (hi : i ≤ a.size)
+    (r : α → α → Bool) (a b : Array α) (hsz : a.size = b.size) (i : Nat) (hi : i ≤ a.size)
     (heqv : Array.isEqvAux a b hsz r i hi)
-    {j : Nat} (hj : j < i) : r (a[j]'(Nat.lt_of_lt_of_le hj hi)) (b[j]'(Nat.lt_of_lt_of_le hj (hsz ▸ hi))) := by
+    (j : Nat) (hj : j < i) : r (a[j]'(Nat.lt_of_lt_of_le hj hi)) (b[j]'(Nat.lt_of_lt_of_le hj (hsz ▸ hi))) := by
   induction i with
   | zero => contradiction
   | succ i ih =>
@@ -27,46 +26,15 @@ theorem rel_of_isEqvAux
       subst hj'
       exact heqv.left
 
-theorem isEqvAux_of_rel {r : α → α → Bool} {a b : Array α} (hsz : a.size = b.size) {i : Nat} (hi : i ≤ a.size)
-    (w : ∀ j, (hj : j < i) → r (a[j]'(Nat.lt_of_lt_of_le hj hi)) (b[j]'(Nat.lt_of_lt_of_le hj (hsz ▸ hi)))) : Array.isEqvAux a b hsz r i hi := by
-  induction i with
-  | zero => simp [Array.isEqvAux]
-  | succ i ih =>
-    simp only [isEqvAux, Bool.and_eq_true]
-    exact ⟨w i (Nat.lt_add_one i), ih _ fun j hj => w j (Nat.lt_add_right 1 hj)⟩
-
-theorem rel_of_isEqv {r : α → α → Bool} {a b : Array α} :
+theorem rel_of_isEqv (r : α → α → Bool) (a b : Array α) :
     Array.isEqv a b r → ∃ h : a.size = b.size, ∀ (i : Nat) (h' : i < a.size), r (a[i]) (b[i]'(h ▸ h')) := by
   simp only [isEqv]
   split <;> rename_i h
-  · exact fun h' => ⟨h, fun i => rel_of_isEqvAux h (Nat.le_refl ..) h'⟩
+  · exact fun h' => ⟨h, rel_of_isEqvAux r a b h a.size (Nat.le_refl ..) h'⟩
   · intro; contradiction
 
-theorem isEqv_iff_rel (a b : Array α) (r) :
-    Array.isEqv a b r ↔ ∃ h : a.size = b.size, ∀ (i : Nat) (h' : i < a.size), r (a[i]) (b[i]'(h ▸ h')) :=
-  ⟨rel_of_isEqv, fun ⟨h, w⟩ => by
-    simp only [isEqv, ← h, ↓reduceDIte]
-    exact isEqvAux_of_rel h (by simp [h]) w⟩
-
-theorem isEqv_eq_decide (a b : Array α) (r) :
-    Array.isEqv a b r =
-      if h : a.size = b.size then decide (∀ (i : Nat) (h' : i < a.size), r (a[i]) (b[i]'(h ▸ h'))) else false := by
-  by_cases h : Array.isEqv a b r
-  · simp only [h, Bool.true_eq]
-    simp only [isEqv_iff_rel] at h
-    obtain ⟨h, w⟩ := h
-    simp [h, w]
-  · let h' := h
-    simp only [Bool.not_eq_true] at h
-    simp only [h, Bool.false_eq, dite_eq_right_iff, decide_eq_false_iff_not, Classical.not_forall,
-      Bool.not_eq_true]
-    simpa [isEqv_iff_rel] using h'
-
-@[simp] theorem isEqv_toList [BEq α] (a b : Array α) : (a.toList.isEqv b.toList r) = (a.isEqv b r) := by
-  simp [isEqv_eq_decide, List.isEqv_eq_decide]
-
 theorem eq_of_isEqv [DecidableEq α] (a b : Array α) (h : Array.isEqv a b (fun x y => x = y)) : a = b := by
-  have ⟨h, h'⟩ := rel_of_isEqv h
+  have ⟨h, h'⟩ := rel_of_isEqv (fun x y => x = y) a b h
   exact ext _ _ h (fun i lt _ => by simpa using h' i lt)
 
 theorem isEqvAux_self (r : α → α → Bool) (hr : ∀ a, r a a) (a : Array α) (i : Nat) (h : i ≤ a.size) :
@@ -88,22 +56,4 @@ instance [DecidableEq α] : DecidableEq (Array α) :=
     | true  => isTrue (eq_of_isEqv a b h)
     | false => isFalse fun h' => by subst h'; rw [isEqv_self] at h; contradiction
 
-theorem beq_eq_decide [BEq α] (a b : Array α) :
-    (a == b) = if h : a.size = b.size then
-      decide (∀ (i : Nat) (h' : i < a.size), a[i] == b[i]'(h ▸ h')) else false := by
-  simp [BEq.beq, isEqv_eq_decide]
-
-@[simp] theorem beq_toList [BEq α] (a b : Array α) : (a.toList == b.toList) = (a == b) := by
-  simp [beq_eq_decide, List.beq_eq_decide]
-
 end Array
-
-namespace List
-
-@[simp] theorem isEqv_toArray [BEq α] (a b : List α) : (a.toArray.isEqv b.toArray r) = (a.isEqv b r) := by
-  simp [isEqv_eq_decide, Array.isEqv_eq_decide]
-
-@[simp] theorem beq_toArray [BEq α] (a b : List α) : (a.toArray == b.toArray) = (a == b) := by
-  simp [beq_eq_decide, Array.beq_eq_decide]
-
-end List

src/Init/Data/Array/FinRange.lean

@@ -1,14 +0,0 @@
-/-
-Copyright (c) 2024 François G. Dorais. All rights reserved.
-Released under Apache 2.0 license as described in the file LICENSE.
-Authors: François G. Dorais
--/
-prelude
-import Init.Data.List.FinRange
-
-namespace Array
-
-/-- `finRange n` is the array of all elements of `Fin n` in order. -/
-protected def finRange (n : Nat) : Array (Fin n) := ofFn fun i => i
-
-end Array

src/Init/Data/Array/Find.lean

@@ -1,281 +0,0 @@
-/-
-Copyright (c) 2024 Lean FRO, LLC. All rights reserved.
-Released under Apache 2.0 license as described in the file LICENSE.
-Authors: Kim Morrison
--/
-prelude
-import Init.Data.List.Find
-import Init.Data.Array.Lemmas
-import Init.Data.Array.Attach
-
-/-!
-# Lemmas about `Array.findSome?`, `Array.find?`.
--/
-
-namespace Array
-
-open Nat
-
-/-! ### findSome? -/
-
-@[simp] theorem findSomeRev?_push_of_isSome (l : Array α) (h : (f a).isSome) : (l.push a).findSomeRev? f = f a := by
-  cases l; simp_all
-
-@[simp] theorem findSomeRev?_push_of_isNone (l : Array α) (h : (f a).isNone) : (l.push a).findSomeRev? f = l.findSomeRev? f := by
-  cases l; simp_all
-
-theorem exists_of_findSome?_eq_some {f : α → Option β} {l : Array α} (w : l.findSome? f = some b) :
-    ∃ a, a ∈ l ∧ f a = b := by
-  cases l; simp_all [List.exists_of_findSome?_eq_some]
-
-@[simp] theorem findSome?_eq_none_iff : findSome? p l = none ↔ ∀ x ∈ l, p x = none := by
-  cases l; simp
-
-@[simp] theorem findSome?_isSome_iff {f : α → Option β} {l : Array α} :
-    (l.findSome? f).isSome ↔ ∃ x, x ∈ l ∧ (f x).isSome := by
-  cases l; simp
-
-theorem findSome?_eq_some_iff {f : α → Option β} {l : Array α} {b : β} :
-    l.findSome? f = some b ↔ ∃ (l₁ : Array α) (a : α) (l₂ : Array α), l = l₁.push a ++ l₂ ∧ f a = some b ∧ ∀ x ∈ l₁, f x = none := by
-  cases l
-  simp only [List.findSome?_toArray, List.findSome?_eq_some_iff]
-  constructor
-  · rintro ⟨l₁, a, l₂, rfl, h₁, h₂⟩
-    exact ⟨l₁.toArray, a, l₂.toArray, by simp_all⟩
-  · rintro ⟨l₁, a, l₂, h₀, h₁, h₂⟩
-    exact ⟨l₁.toList, a, l₂.toList, by simpa using congrArg toList h₀, h₁, by simpa⟩
-
-@[simp] theorem findSome?_guard (l : Array α) : findSome? (Option.guard fun x => p x) l = find? p l := by
-  cases l; simp
-
-@[simp] theorem getElem?_zero_filterMap (f : α → Option β) (l : Array α) : (l.filterMap f)[0]? = l.findSome? f := by
-  cases l; simp [← List.head?_eq_getElem?]
-
-@[simp] theorem getElem_zero_filterMap (f : α → Option β) (l : Array α) (h) :
-    (l.filterMap f)[0] = (l.findSome? f).get (by cases l; simpa [List.length_filterMap_eq_countP] using h) := by
-  cases l; simp [← List.head_eq_getElem, ← getElem?_zero_filterMap]
-
-@[simp] theorem back?_filterMap (f : α → Option β) (l : Array α) : (l.filterMap f).back? = l.findSomeRev? f := by
-  cases l; simp
-
-@[simp] theorem back!_filterMap [Inhabited β] (f : α → Option β) (l : Array α) :
-    (l.filterMap f).back! = (l.findSomeRev? f).getD default := by
-  cases l; simp
-
-@[simp] theorem map_findSome? (f : α → Option β) (g : β → γ) (l : Array α) :
-    (l.findSome? f).map g = l.findSome? (Option.map g ∘ f) := by
-  cases l; simp
-
-theorem findSome?_map (f : β → γ) (l : Array β) : findSome? p (l.map f) = l.findSome? (p ∘ f) := by
-  cases l; simp [List.findSome?_map]
-
-theorem findSome?_append {l₁ l₂ : Array α} : (l₁ ++ l₂).findSome? f = (l₁.findSome? f).or (l₂.findSome? f) := by
-  cases l₁; cases l₂; simp [List.findSome?_append]
-
-theorem getElem?_zero_flatten (L : Array (Array α)) :
-    (flatten L)[0]? = L.findSome? fun l => l[0]? := by
-  cases L using array_array_induction
-  simp [← List.head?_eq_getElem?, List.head?_flatten, List.findSome?_map, Function.comp_def]
-
-theorem getElem_zero_flatten.proof {L : Array (Array α)} (h : 0 < L.flatten.size) :
-    (L.findSome? fun l => l[0]?).isSome := by
-  cases L using array_array_induction
-  simp only [List.findSome?_toArray, List.findSome?_map, Function.comp_def, List.getElem?_toArray,
-    List.findSome?_isSome_iff, isSome_getElem?]
-  simp only [flatten_toArray_map_toArray, size_toArray, List.length_flatten,
-    Nat.sum_pos_iff_exists_pos, List.mem_map] at h
-  obtain ⟨_, ⟨xs, m, rfl⟩, h⟩ := h
-  exact ⟨xs, m, by simpa using h⟩
-
-theorem getElem_zero_flatten {L : Array (Array α)} (h) :
-    (flatten L)[0] = (L.findSome? fun l => l[0]?).get (getElem_zero_flatten.proof h) := by
-  have t := getElem?_zero_flatten L
-  simp [getElem?_eq_getElem, h] at t
-  simp [← t]
-
-theorem back?_flatten {L : Array (Array α)} :
-    (flatten L).back? = (L.findSomeRev? fun l => l.back?) := by
-  cases L using array_array_induction
-  simp [List.getLast?_flatten, ← List.map_reverse, List.findSome?_map, Function.comp_def]
-
-theorem findSome?_mkArray : findSome? f (mkArray n a) = if n = 0 then none else f a := by
-  simp [mkArray_eq_toArray_replicate, List.findSome?_replicate]
-
-@[simp] theorem findSome?_mkArray_of_pos (h : 0 < n) : findSome? f (mkArray n a) = f a := by
-  simp [findSome?_mkArray, Nat.ne_of_gt h]
-
--- Argument is unused, but used to decide whether `simp` should unfold.
-@[simp] theorem findSome?_mkArray_of_isSome (_ : (f a).isSome) :
-   findSome? f (mkArray n a) = if n = 0 then none else f a := by
-  simp [findSome?_mkArray]
-
-@[simp] theorem findSome?_mkArray_of_isNone (h : (f a).isNone) :
-    findSome? f (mkArray n a) = none := by
-  rw [Option.isNone_iff_eq_none] at h
-  simp [findSome?_mkArray, h]
-
-/-! ### find? -/
-
-@[simp] theorem find?_singleton (a : α) (p : α → Bool) :
-    #[a].find? p = if p a then some a else none := by
-  simp [singleton_eq_toArray_singleton]
-
-@[simp] theorem findRev?_push_of_pos (l : Array α) (h : p a) :
-    findRev? p (l.push a) = some a := by
-  cases l; simp [h]
-
-@[simp] theorem findRev?_cons_of_neg (l : Array α) (h : ¬p a) :
-    findRev? p (l.push a) = findRev? p l := by
-  cases l; simp [h]
-
-@[simp] theorem find?_eq_none : find? p l = none ↔ ∀ x ∈ l, ¬ p x := by
-  cases l; simp
-
-theorem find?_eq_some_iff_append {xs : Array α} :
-    xs.find? p = some b ↔ p b ∧ ∃ (as bs : Array α), xs = as.push b ++ bs ∧ ∀ a ∈ as, !p a := by
-  rcases xs with ⟨xs⟩
-  simp only [List.find?_toArray, List.find?_eq_some_iff_append, Bool.not_eq_eq_eq_not,
-    Bool.not_true, exists_and_right, and_congr_right_iff]
-  intro w
-  constructor
-  · rintro ⟨as, ⟨⟨x, rfl⟩, h⟩⟩
-    exact ⟨as.toArray, ⟨x.toArray, by simp⟩ , by simpa using h⟩
-  · rintro ⟨as, ⟨⟨x, h'⟩, h⟩⟩
-    exact ⟨as.toList, ⟨x.toList, by simpa using congrArg Array.toList h'⟩,
-      by simpa using h⟩
-
-@[simp]
-theorem find?_push_eq_some {xs : Array α} :
-    (xs.push a).find? p = some b ↔ xs.find? p = some b ∨ (xs.find? p = none ∧ (p a ∧ a = b)) := by
-  cases xs; simp
-
-@[simp] theorem find?_isSome {xs : Array α} {p : α → Bool} : (xs.find? p).isSome ↔ ∃ x, x ∈ xs ∧ p x := by
-  cases xs; simp
-
-theorem find?_some {xs : Array α} (h : find? p xs = some a) : p a := by
-  cases xs
-  simp at h
-  exact List.find?_some h
-
-theorem mem_of_find?_eq_some {xs : Array α} (h : find? p xs = some a) : a ∈ xs := by
-  cases xs
-  simp at h
-  simpa using List.mem_of_find?_eq_some h
-
-theorem get_find?_mem {xs : Array α} (h) : (xs.find? p).get h ∈ xs := by
-  cases xs
-  simp [List.get_find?_mem]
-
-@[simp] theorem find?_filter {xs : Array α} (p q : α → Bool) :
-    (xs.filter p).find? q = xs.find? (fun a => p a ∧ q a) := by
-  cases xs; simp
-
-@[simp] theorem getElem?_zero_filter (p : α → Bool) (l : Array α) :
-    (l.filter p)[0]? = l.find? p := by
-  cases l; simp [← List.head?_eq_getElem?]
-
-@[simp] theorem getElem_zero_filter (p : α → Bool) (l : Array α) (h) :
-    (l.filter p)[0] =
-      (l.find? p).get (by cases l; simpa [← List.countP_eq_length_filter] using h) := by
-  cases l
-  simp [List.getElem_zero_eq_head]
-
-@[simp] theorem back?_filter (p : α → Bool) (l : Array α) : (l.filter p).back? = l.findRev? p := by
-  cases l; simp
-
-@[simp] theorem back!_filter [Inhabited α] (p : α → Bool) (l : Array α) :
-    (l.filter p).back! = (l.findRev? p).get! := by
-  cases l; simp [Option.get!_eq_getD]
-
-@[simp] theorem find?_filterMap (xs : Array α) (f : α → Option β) (p : β → Bool) :
-    (xs.filterMap f).find? p = (xs.find? (fun a => (f a).any p)).bind f := by
-  cases xs; simp
-
-@[simp] theorem find?_map (f : β → α) (xs : Array β) :
-    find? p (xs.map f) = (xs.find? (p ∘ f)).map f := by
-  cases xs; simp
-
-@[simp] theorem find?_append {l₁ l₂ : Array α} :
-    (l₁ ++ l₂).find? p = (l₁.find? p).or (l₂.find? p) := by
-  cases l₁
-  cases l₂
-  simp
-
-@[simp] theorem find?_flatten (xs : Array (Array α)) (p : α → Bool) :
-    xs.flatten.find? p = xs.findSome? (·.find? p) := by
-  cases xs using array_array_induction
-  simp [List.findSome?_map, Function.comp_def]
-
-theorem find?_flatten_eq_none {xs : Array (Array α)} {p : α → Bool} :
-    xs.flatten.find? p = none ↔ ∀ ys ∈ xs, ∀ x ∈ ys, !p x := by
-  simp
-
-/--
-If `find? p` returns `some a` from `xs.flatten`, then `p a` holds, and
-some array in `xs` contains `a`, and no earlier element of that array satisfies `p`.
-Moreover, no earlier array in `xs` has an element satisfying `p`.
--/
-theorem find?_flatten_eq_some {xs : Array (Array α)} {p : α → Bool} {a : α} :
-    xs.flatten.find? p = some a ↔
-      p a ∧ ∃ (as : Array (Array α)) (ys zs : Array α) (bs : Array (Array α)),
-        xs = as.push (ys.push a ++ zs) ++ bs ∧
-        (∀ a ∈ as, ∀ x ∈ a, !p x) ∧ (∀ x ∈ ys, !p x) := by
-  cases xs using array_array_induction
-  simp only [flatten_toArray_map_toArray, List.find?_toArray, List.find?_flatten_eq_some]
-  simp only [Bool.not_eq_eq_eq_not, Bool.not_true, exists_and_right, and_congr_right_iff]
-  intro w
-  constructor
-  · rintro ⟨as, ys, ⟨⟨zs, bs, rfl⟩, h₁, h₂⟩⟩
-    exact ⟨as.toArray.map List.toArray, ys.toArray,
-      ⟨zs.toArray, bs.toArray.map List.toArray, by simp⟩, by simpa using h₁, by simpa using h₂⟩
-  · rintro ⟨as, ys, ⟨⟨zs, bs, h⟩, h₁, h₂⟩⟩
-    replace h := congrArg (·.map Array.toList) (congrArg Array.toList h)
-    simp [Function.comp_def] at h
-    exact ⟨as.toList.map Array.toList, ys.toList,
-      ⟨zs.toList, bs.toList.map Array.toList, by simpa using h⟩,
-        by simpa using h₁, by simpa using h₂⟩
-
-@[simp] theorem find?_flatMap (xs : Array α) (f : α → Array β) (p : β → Bool) :
-    (xs.flatMap f).find? p = xs.findSome? (fun x => (f x).find? p) := by
-  cases xs
-  simp [List.find?_flatMap, Array.flatMap_toArray]
-
-theorem find?_flatMap_eq_none {xs : Array α} {f : α → Array β} {p : β → Bool} :
-    (xs.flatMap f).find? p = none ↔ ∀ x ∈ xs, ∀ y ∈ f x, !p y := by
-  simp
-
-theorem find?_mkArray :
-    find? p (mkArray n a) = if n = 0 then none else if p a then some a else none := by
-  simp [mkArray_eq_toArray_replicate, List.find?_replicate]
-
-@[simp] theorem find?_mkArray_of_length_pos (h : 0 < n) :
-    find? p (mkArray n a) = if p a then some a else none := by
-  simp [find?_mkArray, Nat.ne_of_gt h]
-
-@[simp] theorem find?_mkArray_of_pos (h : p a) :
-    find? p (mkArray n a) = if n = 0 then none else some a := by
-  simp [find?_mkArray, h]
-
-@[simp] theorem find?_mkArray_of_neg (h : ¬ p a) : find? p (mkArray n a) = none := by
-  simp [find?_mkArray, h]
-
--- This isn't a `@[simp]` lemma since there is already a lemma for `l.find? p = none` for any `l`.
-theorem find?_mkArray_eq_none {n : Nat} {a : α} {p : α → Bool} :
-    (mkArray n a).find? p = none ↔ n = 0 ∨ !p a := by
-  simp [mkArray_eq_toArray_replicate, List.find?_replicate_eq_none, Classical.or_iff_not_imp_left]
-
-@[simp] theorem find?_mkArray_eq_some {n : Nat} {a b : α} {p : α → Bool} :
-    (mkArray n a).find? p = some b ↔ n ≠ 0 ∧ p a ∧ a = b := by
-  simp [mkArray_eq_toArray_replicate]
-
-@[simp] theorem get_find?_mkArray (n : Nat) (a : α) (p : α → Bool) (h) :
-    ((mkArray n a).find? p).get h = a := by
-  simp [mkArray_eq_toArray_replicate]
-
-theorem find?_pmap {P : α → Prop} (f : (a : α) → P a → β) (xs : Array α)
-    (H : ∀ (a : α), a ∈ xs → P a) (p : β → Bool) :
-    (xs.pmap f H).find? p = (xs.attach.find? (fun ⟨a, m⟩ => p (f a (H a m)))).map fun ⟨a, m⟩ => f a (H a m) := by
-  simp only [pmap_eq_map_attach, find?_map]
-  rfl
-
-end Array

src/Init/Data/Array/GetLit.lean

@@ -41,6 +41,6 @@ where
   getLit_eq (as : Array α) (i : Nat) (h₁ : as.size = n) (h₂ : i < n) : as.getLit i h₁ h₂ = getElem as.toList i ((id (α := as.toList.length = n) h₁) ▸ h₂) :=
     rfl
   go (i : Nat) (hi : i ≤ as.size) : toListLitAux as n hsz i hi (as.toList.drop i) = as.toList := by
-    induction i <;> simp only [List.drop, toListLitAux, getLit_eq, List.getElem_cons_drop_succ_eq_drop, *]
+    induction i <;> simp [getLit_eq, List.get_drop_eq_drop, toListLitAux, List.drop, *]
 
 end Array

src/Init/Data/Array/InsertionSort.lean

@@ -6,7 +6,7 @@ Authors: Leonardo de Moura
 prelude
 import Init.Data.Array.Basic
 
-@[inline] def Array.insertionSort (a : Array α) (lt : α → α → Bool := by exact (· < ·)) : Array α :=
+@[inline] def Array.insertionSort (a : Array α) (lt : α → α → Bool) : Array α :=
   traverse a 0 a.size
 where
   @[specialize] traverse (a : Array α) (i : Nat) (fuel : Nat) : Array α :=
@@ -23,6 +23,6 @@ where
     | j'+1 =>
       have h' : j' < a.size := by subst j; exact Nat.lt_trans (Nat.lt_succ_self _) h
       if lt a[j] a[j'] then
-        swapLoop (a.swap j j') j' (by rw [size_swap]; assumption; done)
+        swapLoop (a.swap ⟨j, h⟩ ⟨j', h'⟩) j' (by rw [size_swap]; assumption; done)
       else
         a

src/Init/Data/Array/MapIdx.lean

@@ -1,112 +0,0 @@
-/-
-Copyright (c) 2022 Mario Carneiro. All rights reserved.
-Released under Apache 2.0 license as described in the file LICENSE.
-Authors: Mario Carneiro, Kim Morrison
--/
-prelude
-import Init.Data.Array.Lemmas
-import Init.Data.List.MapIdx
-
-namespace Array
-
-/-! ### mapFinIdx -/
-
--- This could also be proved from `SatisfiesM_mapIdxM` in Batteries.
-theorem mapFinIdx_induction (as : Array α) (f : Fin as.size → α → β)
-    (motive : Nat → Prop) (h0 : motive 0)
-    (p : Fin as.size → β → Prop)
-    (hs : ∀ i, motive i.1 → p i (f i as[i]) ∧ motive (i + 1)) :
-    motive as.size ∧ ∃ eq : (Array.mapFinIdx as f).size = as.size,
-      ∀ i h, p ⟨i, h⟩ ((Array.mapFinIdx as f)[i]) := by
-  let rec go {bs i j h} (h₁ : j = bs.size) (h₂ : ∀ i h h', p ⟨i, h⟩ bs[i]) (hm : motive j) :
-    let arr : Array β := Array.mapFinIdxM.map (m := Id) as f i j h bs
-    motive as.size ∧ ∃ eq : arr.size = as.size, ∀ i h, p ⟨i, h⟩ arr[i] := by
-    induction i generalizing j bs with simp [mapFinIdxM.map]
-    | zero =>
-      have := (Nat.zero_add _).symm.trans h
-      exact ⟨this ▸ hm, h₁ ▸ this, fun _ _ => h₂ ..⟩
-    | succ i ih =>
-      apply @ih (bs.push (f ⟨j, by omega⟩ as[j])) (j + 1) (by omega) (by simp; omega)
-      · intro i i_lt h'
-        rw [getElem_push]
-        split
-        · apply h₂
-        · simp only [size_push] at h'
-          obtain rfl : i = j := by omega
-          apply (hs ⟨i, by omega⟩ hm).1
-      · exact (hs ⟨j, by omega⟩ hm).2
-  simp [mapFinIdx, mapFinIdxM]; exact go rfl nofun h0
-
-theorem mapFinIdx_spec (as : Array α) (f : Fin as.size → α → β)
-    (p : Fin as.size → β → Prop) (hs : ∀ i, p i (f i as[i])) :
-    ∃ eq : (Array.mapFinIdx as f).size = as.size,
-      ∀ i h, p ⟨i, h⟩ ((Array.mapFinIdx as f)[i]) :=
-  (mapFinIdx_induction _ _ (fun _ => True) trivial p fun _ _ => ⟨hs .., trivial⟩).2
-
-@[simp] theorem size_mapFinIdx (a : Array α) (f : Fin a.size → α → β) : (a.mapFinIdx f).size = a.size :=
-  (mapFinIdx_spec (p := fun _ _ => True) (hs := fun _ => trivial)).1
-
-@[simp] theorem size_zipWithIndex (as : Array α) : as.zipWithIndex.size = as.size :=
-  Array.size_mapFinIdx _ _
-
-@[simp] theorem getElem_mapFinIdx (a : Array α) (f : Fin a.size → α → β) (i : Nat)
-    (h : i < (mapFinIdx a f).size) :
-    (a.mapFinIdx f)[i] = f ⟨i, by simp_all⟩ (a[i]'(by simp_all)) :=
-  (mapFinIdx_spec _ _ (fun i b => b = f i a[i]) fun _ => rfl).2 i _
-
-@[simp] theorem getElem?_mapFinIdx (a : Array α) (f : Fin a.size → α → β) (i : Nat) :
-    (a.mapFinIdx f)[i]? =
-      a[i]?.pbind fun b h => f ⟨i, (getElem?_eq_some_iff.1 h).1⟩ b := by
-  simp only [getElem?_def, size_mapFinIdx, getElem_mapFinIdx]
-  split <;> simp_all
-
-@[simp] theorem toList_mapFinIdx (a : Array α) (f : Fin a.size → α → β) :
-    (a.mapFinIdx f).toList = a.toList.mapFinIdx (fun i a => f ⟨i, by simp⟩ a) := by
-  apply List.ext_getElem <;> simp
-
-/-! ### mapIdx -/
-
-theorem mapIdx_induction (f : Nat → α → β) (as : Array α)
-    (motive : Nat → Prop) (h0 : motive 0)
-    (p : Fin as.size → β → Prop)
-    (hs : ∀ i, motive i.1 → p i (f i as[i]) ∧ motive (i + 1)) :
-    motive as.size ∧ ∃ eq : (as.mapIdx f).size = as.size,
-      ∀ i h, p ⟨i, h⟩ ((as.mapIdx f)[i]) :=
-  mapFinIdx_induction as (fun i a => f i a) motive h0 p hs
-
-theorem mapIdx_spec (f : Nat → α → β) (as : Array α)
-    (p : Fin as.size → β → Prop) (hs : ∀ i, p i (f i as[i])) :
-    ∃ eq : (as.mapIdx f).size = as.size,
-      ∀ i h, p ⟨i, h⟩ ((as.mapIdx f)[i]) :=
-  (mapIdx_induction _ _ (fun _ => True) trivial p fun _ _ => ⟨hs .., trivial⟩).2
-
-@[simp] theorem size_mapIdx (f : Nat → α → β) (as : Array α) : (as.mapIdx f).size = as.size :=
-  (mapIdx_spec (p := fun _ _ => True) (hs := fun _ => trivial)).1
-
-@[simp] theorem getElem_mapIdx (f : Nat → α → β) (as : Array α) (i : Nat)
-    (h : i < (as.mapIdx f).size) :
-    (as.mapIdx f)[i] = f i (as[i]'(by simp_all)) :=
-  (mapIdx_spec _ _ (fun i b => b = f i as[i]) fun _ => rfl).2 i (by simp_all)
-
-@[simp] theorem getElem?_mapIdx (f : Nat → α → β) (as : Array α) (i : Nat) :
-    (as.mapIdx f)[i]? =
-      as[i]?.map (f i) := by
-  simp [getElem?_def, size_mapIdx, getElem_mapIdx]
-
-@[simp] theorem toList_mapIdx (f : Nat → α → β) (as : Array α) :
-    (as.mapIdx f).toList = as.toList.mapIdx (fun i a => f i a) := by
-  apply List.ext_getElem <;> simp
-
-end Array
-
-namespace List
-
-@[simp] theorem mapFinIdx_toArray (l : List α) (f : Fin l.length → α → β) :
-    l.toArray.mapFinIdx f = (l.mapFinIdx f).toArray := by
-  ext <;> simp
-
-@[simp] theorem mapIdx_toArray (f : Nat → α → β) (l : List α) :
-    l.toArray.mapIdx f = (l.mapIdx f).toArray := by
-  ext <;> simp
-
-end List

src/Init/Data/Array/Mem.lean

@@ -10,16 +10,25 @@ import Init.Data.List.BasicAux
 
 namespace Array
 
+/-- `a ∈ as` is a predicate which asserts that `a` is in the array `as`. -/
+-- NB: This is defined as a structure rather than a plain def so that a lemma
+-- like `sizeOf_lt_of_mem` will not apply with no actual arrays around.
+structure Mem (as : Array α) (a : α) : Prop where
+  val : a ∈ as.toList
+
+instance : Membership α (Array α) where
+  mem := Mem
+
 theorem sizeOf_lt_of_mem [SizeOf α] {as : Array α} (h : a ∈ as) : sizeOf a < sizeOf as := by
   cases as with | _ as =>
   exact Nat.lt_trans (List.sizeOf_lt_of_mem h.val) (by simp_arith)
 
-theorem sizeOf_get [SizeOf α] (as : Array α) (i : Nat) (h : i < as.size) : sizeOf (as.get i h) < sizeOf as := by
+theorem sizeOf_get [SizeOf α] (as : Array α) (i : Fin as.size) : sizeOf (as.get i) < sizeOf as := by
   cases as with | _ as =>
-  simpa using Nat.lt_trans (List.sizeOf_get _ ⟨i, h⟩) (by simp_arith)
+  exact Nat.lt_trans (List.sizeOf_get ..) (by simp_arith)
 
 @[simp] theorem sizeOf_getElem [SizeOf α] (as : Array α) (i : Nat) (h : i < as.size) :
-  sizeOf (as[i]'h) < sizeOf as := sizeOf_get _ _ h
+  sizeOf (as[i]'h) < sizeOf as := sizeOf_get _ _
 
 /-- This tactic, added to the `decreasing_trivial` toolbox, proves that
 `sizeOf arr[i] < sizeOf arr`, which is useful for well founded recursions

src/Init/Data/Array/Monadic.lean

@@ -1,159 +0,0 @@
-/-
-Copyright (c) 2024 Lean FRO, LLC. All rights reserved.
-Released under Apache 2.0 license as described in the file LICENSE.
-Authors: Kim Morrison
--/
-prelude
-import Init.Data.Array.Lemmas
-import Init.Data.Array.Attach
-import Init.Data.List.Monadic
-
-/-!
-# Lemmas about `Array.forIn'` and `Array.forIn`.
--/
-
-namespace Array
-
-open Nat
-
-/-! ## Monadic operations -/
-
-/-! ### mapM -/
-
-theorem mapM_eq_foldlM_push [Monad m] [LawfulMonad m] (f : α → m β) (l : Array α) :
-    mapM f l = l.foldlM (fun acc a => return (acc.push (← f a))) #[] := by
-  rcases l with ⟨l⟩
-  simp only [List.mapM_toArray, bind_pure_comp, size_toArray, List.foldlM_toArray']
-  rw [List.mapM_eq_reverse_foldlM_cons]
-  simp only [bind_pure_comp, Functor.map_map]
-  suffices ∀ (k), (fun a => a.reverse.toArray) <$> List.foldlM (fun acc a => (fun a => a :: acc) <$> f a) k l =
-      List.foldlM (fun acc a => acc.push <$> f a) k.reverse.toArray l by
-    exact this []
-  intro k
-  induction l generalizing k with
-  | nil => simp
-  | cons a as ih =>
-    simp [ih, List.foldlM_cons]
-
-/-! ### foldlM and foldrM -/
-
-theorem foldlM_map [Monad m] (f : β₁ → β₂) (g : α → β₂ → m α) (l : Array β₁) (init : α) :
-    (l.map f).foldlM g init = l.foldlM (fun x y => g x (f y)) init := by
-  cases l
-  rw [List.map_toArray] -- Why doesn't this fire via `simp`?
-  simp [List.foldlM_map]
-
-theorem foldrM_map [Monad m] [LawfulMonad m] (f : β₁ → β₂) (g : β₂ → α → m α) (l : Array β₁)
-    (init : α) : (l.map f).foldrM g init = l.foldrM (fun x y => g (f x) y) init := by
-  cases l
-  rw [List.map_toArray] -- Why doesn't this fire via `simp`?
-  simp [List.foldrM_map]
-
-theorem foldlM_filterMap [Monad m] [LawfulMonad m] (f : α → Option β) (g : γ → β → m γ) (l : Array α) (init : γ) :
-    (l.filterMap f).foldlM g init =
-      l.foldlM (fun x y => match f y with | some b => g x b | none => pure x) init := by
-  cases l
-  rw [List.filterMap_toArray] -- Why doesn't this fire via `simp`?
-  simp [List.foldlM_filterMap]
-  rfl
-
-theorem foldrM_filterMap [Monad m] [LawfulMonad m] (f : α → Option β) (g : β → γ → m γ) (l : Array α) (init : γ) :
-    (l.filterMap f).foldrM g init =
-      l.foldrM (fun x y => match f x with | some b => g b y | none => pure y) init := by
-  cases l
-  rw [List.filterMap_toArray] -- Why doesn't this fire via `simp`?
-  simp [List.foldrM_filterMap]
-  rfl
-
-theorem foldlM_filter [Monad m] [LawfulMonad m] (p : α → Bool) (g : β → α → m β) (l : Array α) (init : β) :
-    (l.filter p).foldlM g init =
-      l.foldlM (fun x y => if p y then g x y else pure x) init := by
-  cases l
-  rw [List.filter_toArray] -- Why doesn't this fire via `simp`?
-  simp [List.foldlM_filter]
-
-theorem foldrM_filter [Monad m] [LawfulMonad m] (p : α → Bool) (g : α → β → m β) (l : Array α) (init : β) :
-    (l.filter p).foldrM g init =
-      l.foldrM (fun x y => if p x then g x y else pure y) init := by
-  cases l
-  rw [List.filter_toArray] -- Why doesn't this fire via `simp`?
-  simp [List.foldrM_filter]
-
-/-! ### forIn' -/
-
-/--
-We can express a for loop over an array as a fold,
-in which whenever we reach `.done b` we keep that value through the rest of the fold.
--/
-theorem forIn'_eq_foldlM [Monad m] [LawfulMonad m]
-    (l : Array α) (f : (a : α) → a ∈ l → β → m (ForInStep β)) (init : β) :
-    forIn' l init f = ForInStep.value <$>
-      l.attach.foldlM (fun b ⟨a, m⟩ => match b with
-        | .yield b => f a m b
-        | .done b => pure (.done b)) (ForInStep.yield init) := by
-  cases l
-  rw [List.attach_toArray] -- Why doesn't this fire via `simp`?
-  simp only [List.forIn'_toArray, List.forIn'_eq_foldlM, List.attachWith_mem_toArray, size_toArray,
-    List.length_map, List.length_attach, List.foldlM_toArray', List.foldlM_map]
-  congr
-
-/-- We can express a for loop over an array which always yields as a fold. -/
-@[simp] theorem forIn'_yield_eq_foldlM [Monad m] [LawfulMonad m]
-    (l : Array α) (f : (a : α) → a ∈ l → β → m γ) (g : (a : α) → a ∈ l → β → γ → β) (init : β) :
-    forIn' l init (fun a m b => (fun c => .yield (g a m b c)) <$> f a m b) =
-      l.attach.foldlM (fun b ⟨a, m⟩ => g a m b <$> f a m b) init := by
-  cases l
-  rw [List.attach_toArray] -- Why doesn't this fire via `simp`?
-  simp [List.foldlM_map]
-
-theorem forIn'_pure_yield_eq_foldl [Monad m] [LawfulMonad m]
-    (l : Array α) (f : (a : α) → a ∈ l → β → β) (init : β) :
-    forIn' l init (fun a m b => pure (.yield (f a m b))) =
-      pure (f := m) (l.attach.foldl (fun b ⟨a, h⟩ => f a h b) init) := by
-  cases l
-  simp [List.forIn'_pure_yield_eq_foldl, List.foldl_map]
-
-@[simp] theorem forIn'_yield_eq_foldl
-    (l : Array α) (f : (a : α) → a ∈ l → β → β) (init : β) :
-    forIn' (m := Id) l init (fun a m b => .yield (f a m b)) =
-      l.attach.foldl (fun b ⟨a, h⟩ => f a h b) init := by
-  cases l
-  simp [List.foldl_map]
-
-/--
-We can express a for loop over an array as a fold,
-in which whenever we reach `.done b` we keep that value through the rest of the fold.
--/
-theorem forIn_eq_foldlM [Monad m] [LawfulMonad m]
-    (f : α → β → m (ForInStep β)) (init : β) (l : Array α) :
-    forIn l init f = ForInStep.value <$>
-      l.foldlM (fun b a => match b with
-        | .yield b => f a b
-        | .done b => pure (.done b)) (ForInStep.yield init) := by
-  cases l
-  simp only [List.forIn_toArray, List.forIn_eq_foldlM, size_toArray, List.foldlM_toArray']
-  congr
-
-/-- We can express a for loop over an array which always yields as a fold. -/
-@[simp] theorem forIn_yield_eq_foldlM [Monad m] [LawfulMonad m]
-    (l : Array α) (f : α → β → m γ) (g : α → β → γ → β) (init : β) :
-    forIn l init (fun a b => (fun c => .yield (g a b c)) <$> f a b) =
-      l.foldlM (fun b a => g a b <$> f a b) init := by
-  cases l
-  simp [List.foldlM_map]
-
-theorem forIn_pure_yield_eq_foldl [Monad m] [LawfulMonad m]
-    (l : Array α) (f : α → β → β) (init : β) :
-    forIn l init (fun a b => pure (.yield (f a b))) =
-      pure (f := m) (l.foldl (fun b a => f a b) init) := by
-  cases l
-  simp [List.forIn_pure_yield_eq_foldl, List.foldl_map]
-
-@[simp] theorem forIn_yield_eq_foldl
-    (l : Array α) (f : α → β → β) (init : β) :
-    forIn (m := Id) l init (fun a b => .yield (f a b)) =
-      l.foldl (fun b a => f a b) init := by
-  cases l
-  simp [List.foldl_map]
-
-end Array

src/Init/Data/Array/Perm.lean

@@ -1,65 +0,0 @@
-/-
-Copyright (c) 2024 Lean FRO. All rights reserved.
-Released under Apache 2.0 license as described in the file LICENSE.
-Authors: Kim Morrison
--/
-prelude
-import Init.Data.List.Nat.Perm
-import Init.Data.Array.Lemmas
-
-namespace Array
-
-open List
-
-/--
-`Perm as bs` asserts that `as` and `bs` are permutations of each other.
-
-This is a wrapper around `List.Perm`, and for now has much less API.
-For more complicated verification, use `perm_iff_toList_perm` and the `List` API.
--/
-def Perm (as bs : Array α) : Prop :=
-  as.toList ~ bs.toList
-
-@[inherit_doc] scoped infixl:50 " ~ " => Perm
-
-theorem perm_iff_toList_perm {as bs : Array α} : as ~ bs ↔ as.toList ~ bs.toList := Iff.rfl
-
-@[simp] theorem perm_toArray (as bs : List α) : as.toArray ~ bs.toArray ↔ as ~ bs := by
-  simp [perm_iff_toList_perm]
-
-@[simp, refl] protected theorem Perm.refl (l : Array α) : l ~ l := by
-  cases l
-  simp
-
-protected theorem Perm.rfl {l : List α} : l ~ l := .refl _
-
-theorem Perm.of_eq {l₁ l₂ : Array α} (h : l₁ = l₂) : l₁ ~ l₂ := h ▸ .rfl
-
-protected theorem Perm.symm {l₁ l₂ : Array α} (h : l₁ ~ l₂) : l₂ ~ l₁ := by
-  cases l₁; cases l₂
-  simp only [perm_toArray] at h
-  simpa using h.symm
-
-protected theorem Perm.trans {l₁ l₂ l₃ : Array α} (h₁ : l₁ ~ l₂) (h₂ : l₂ ~ l₃) : l₁ ~ l₃ := by
-  cases l₁; cases l₂; cases l₃
-  simp only [perm_toArray] at h₁ h₂
-  simpa using h₁.trans h₂
-
-instance : Trans (Perm (α := α)) (Perm (α := α)) (Perm (α := α)) where
-  trans h₁ h₂ := Perm.trans h₁ h₂
-
-theorem perm_comm {l₁ l₂ : Array α} : l₁ ~ l₂ ↔ l₂ ~ l₁ := ⟨Perm.symm, Perm.symm⟩
-
-theorem Perm.push (x y : α) {l₁ l₂ : Array α} (p : l₁ ~ l₂) :
-    (l₁.push x).push y ~ (l₂.push y).push x := by
-  cases l₁; cases l₂
-  simp only [perm_toArray] at p
-  simp only [push_toArray, List.append_assoc, singleton_append, perm_toArray]
-  exact p.append (Perm.swap' _ _ Perm.nil)
-
-theorem swap_perm {as : Array α} {i j : Nat} (h₁ : i < as.size) (h₂ : j < as.size) :
-    as.swap i j ~ as := by
-  simp only [swap, perm_iff_toList_perm, toList_set]
-  apply set_set_perm
-
-end Array

src/Init/Data/Array/QSort.lean

@@ -4,52 +4,44 @@ Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Leonardo de Moura
 -/
 prelude
-import Init.Data.Vector.Basic
-import Init.Data.Ord
+import Init.Data.Array.Basic
 
 namespace Array
+-- TODO: remove the [Inhabited α] parameters as soon as we have the tactic framework for automating proof generation and using Array.fget
 
-private def qpartition {n} (as : Vector α n) (lt : α → α → Bool) (lo hi : Nat)
-    (hlo : lo < n := by omega) (hhi : hi < n := by omega) : {n : Nat // lo ≤ n} × Vector α n :=
+def qpartition (as : Array α) (lt : α → α → Bool) (lo hi : Nat) : Nat × Array α :=
+  if h : as.size = 0 then (0, as) else have : Inhabited α := ⟨as[0]'(by revert h; cases as.size <;> simp)⟩ -- TODO: remove
   let mid := (lo + hi) / 2
-  let as  := if lt as[mid] as[lo] then as.swap lo mid else as
-  let as  := if lt as[hi]  as[lo] then as.swap lo hi  else as
-  let as  := if lt as[mid] as[hi] then as.swap mid hi else as
-  let pivot := as[hi]
-  let rec loop (as : Vector α n) (i j : Nat)
-      (ilo : lo ≤ i := by omega) (jh : j < n := by omega) (w : i ≤ j := by omega) :=
+  let as  := if lt (as.get! mid) (as.get! lo) then as.swap! lo mid else as
+  let as  := if lt (as.get! hi)  (as.get! lo) then as.swap! lo hi  else as
+  let as  := if lt (as.get! mid) (as.get! hi) then as.swap! mid hi else as
+  let pivot := as.get! hi
+  let rec loop (as : Array α) (i j : Nat) :=
     if h : j < hi then
-      if lt as[j] pivot then
-        loop (as.swap i j) (i+1) (j+1)
+      if lt (as.get! j) pivot then
+        let as := as.swap! i j
+        loop as (i+1) (j+1)
       else
         loop as i (j+1)
     else
-      (⟨i, ilo⟩, as.swap i hi)
+      let as := as.swap! i hi
+      (i, as)
+    termination_by hi - j
+    decreasing_by all_goals simp_wf; decreasing_trivial_pre_omega
   loop as lo lo
 
-@[inline] def qsort (as : Array α) (lt : α → α → Bool := by exact (· < ·))
-    (low := 0) (high := as.size - 1) : Array α :=
-  let rec @[specialize] sort {n} (as : Vector α n) (lo hi : Nat)
-      (hlo : lo < n := by omega) (hhi : hi < n := by omega) :=
-    if h₁ : lo < hi then
-      let ⟨⟨mid, hmid⟩, as⟩ := qpartition as lt lo hi
-      if h₂ : mid ≥ hi then
-        as
+@[inline] partial def qsort (as : Array α) (lt : α → α → Bool) (low := 0) (high := as.size - 1) : Array α :=
+  let rec @[specialize] sort (as : Array α) (low high : Nat) :=
+    if low < high then
+      let p := qpartition as lt low high;
+      -- TODO: fix `partial` support in the equation compiler, it breaks if we use `let (mid, as) := partition as lt low high`
+      let mid := p.1
+      let as  := p.2
+      if mid >= high then as
       else
-        sort (sort as lo mid) (mid+1) hi
+        let as := sort as low mid
+        sort as (mid+1) high
     else as
-  if h : as.size = 0 then
-    as
-  else
-    let low := min low (as.size - 1)
-    let high := min high (as.size - 1)
-    sort ⟨as, rfl⟩ low high |>.toArray
-
-set_option linter.unusedVariables.funArgs false in
-/--
-Sort an array using `compare` to compare elements.
--/
-def qsortOrd [ord : Ord α] (xs : Array α) : Array α :=
-  xs.qsort fun x y => compare x y |>.isLT
+  sort as low high
 
 end Array

src/Init/Data/Array/Set.lean

@@ -1,41 +0,0 @@
-/-
-Copyright (c) 2020 Microsoft Corporation. All rights reserved.
-Released under Apache 2.0 license as described in the file LICENSE.
-Authors: Leonardo de Moura, Mario Carneiro
--/
-prelude
-import Init.Tactics
-
-
-/--
-Set an element in an array, using a proof that the index is in bounds.
-(This proof can usually be omitted, and will be synthesized automatically.)
-
-This will perform the update destructively provided that `a` has a reference
-count of 1 when called.
--/
-@[extern "lean_array_fset"]
-def Array.set (a : Array α) (i : @& Nat) (v : α) (h : i < a.size := by get_elem_tactic) :
-    Array α where
-  toList := a.toList.set i v
-
-/--
-Set an element in an array, or do nothing if the index is out of bounds.
-
-This will perform the update destructively provided that `a` has a reference
-count of 1 when called.
--/
-@[inline] def Array.setIfInBounds (a : Array α) (i : Nat) (v : α) : Array α :=
-  dite (LT.lt i a.size) (fun h => a.set i v h) (fun _ => a)
-
-@[deprecated Array.setIfInBounds (since := "2024-11-24")] abbrev Array.setD := @Array.setIfInBounds
-
-/--
-Set an element in an array, or panic if the index is out of bounds.
-
-This will perform the update destructively provided that `a` has a reference
-count of 1 when called.
--/
-@[extern "lean_array_set"]
-def Array.set! (a : Array α) (i : @& Nat) (v : α) : Array α :=
-  Array.setIfInBounds a i v

src/Init/Data/Array/Subarray.lean

@@ -15,6 +15,15 @@ structure Subarray (α : Type u)  where
   start_le_stop : start ≤ stop
   stop_le_array_size : stop ≤ array.size
 
+@[deprecated Subarray.array (since := "2024-04-13")]
+abbrev Subarray.as (s : Subarray α) : Array α := s.array
+
+@[deprecated Subarray.start_le_stop (since := "2024-04-13")]
+theorem Subarray.h₁ (s : Subarray α) : s.start ≤ s.stop := s.start_le_stop
+
+@[deprecated Subarray.stop_le_array_size (since := "2024-04-13")]
+theorem Subarray.h₂ (s : Subarray α) : s.stop ≤ s.array.size := s.stop_le_array_size
+
 namespace Subarray
 
 def size (s : Subarray α) : Nat :=
@@ -39,7 +48,7 @@ instance : GetElem (Subarray α) Nat α fun xs i => i < xs.size where
   getElem xs i h := xs.get ⟨i, h⟩
 
 @[inline] def getD (s : Subarray α) (i : Nat) (v₀ : α) : α :=
-  if h : i < s.size then s[i] else v₀
+  if h : i < s.size then s.get ⟨i, h⟩ else v₀
 
 abbrev get! [Inhabited α] (s : Subarray α) (i : Nat) : α :=
   getD s i default
@@ -50,22 +59,6 @@ def popFront (s : Subarray α) : Subarray α :=
   else
     s
 
-/--
-The empty subarray.
--/
-protected def empty : Subarray α where
-  array := #[]
-  start := 0
-  stop := 0
-  start_le_stop := Nat.le_refl 0
-  stop_le_array_size := Nat.le_refl 0
-
-instance : EmptyCollection (Subarray α) :=
-  ⟨Subarray.empty⟩
-
-instance : Inhabited (Subarray α) :=
-  ⟨{}⟩
-
 @[inline] unsafe def forInUnsafe {α : Type u} {β : Type v} {m : Type v → Type w} [Monad m] (s : Subarray α) (b : β) (f : α → β → m (ForInStep β)) : m β :=
   let sz := USize.ofNat s.stop
   let rec @[specialize] loop (i : USize) (b : β) : m β := do

src/Init/Data/Array/Subarray/Split.lean

@@ -23,13 +23,16 @@ def split (s : Subarray α) (i : Fin s.size.succ) : (Subarray α × Subarray α)
   let ⟨i', isLt⟩ := i
   have := s.start_le_stop
   have := s.stop_le_array_size
+  have : i' ≤ s.stop - s.start := Nat.lt_succ.mp isLt
+  have : s.start + i' ≤ s.stop := by omega
+  have : s.start + i' ≤ s.array.size := by omega
   have : s.start + i' ≤ s.stop := by
     simp only [size] at isLt
     omega
   let pre := {s with
     stop := s.start + i',
     start_le_stop := by omega,
-    stop_le_array_size := by omega
+    stop_le_array_size := by assumption
   }
   let post := {s with
     start := s.start + i'
@@ -45,7 +48,9 @@ def drop (arr : Subarray α) (i : Nat) : Subarray α where
   array := arr.array
   start := min (arr.start + i) arr.stop
   stop := arr.stop
-  start_le_stop := by omega
+  start_le_stop := by
+    rw [Nat.min_def]
+    split <;> simp only [Nat.le_refl, *]
   stop_le_array_size := arr.stop_le_array_size
 
 /--
@@ -58,7 +63,9 @@ def take (arr : Subarray α) (i : Nat) : Subarray α where
   stop := min (arr.start + i) arr.stop
   start_le_stop := by
     have := arr.start_le_stop
-    omega
+    rw [Nat.min_def]
+    split <;> omega
   stop_le_array_size := by
     have := arr.stop_le_array_size
-    omega
+    rw [Nat.min_def]
+    split <;> omega

src/Init/Data/Array/TakeDrop.lean

@@ -12,7 +12,7 @@ namespace Array
 theorem exists_of_uset (self : Array α) (i d h) :
     ∃ l₁ l₂, self.toList = l₁ ++ self[i] :: l₂ ∧ List.length l₁ = i.toNat ∧
       (self.uset i d h).toList = l₁ ++ d :: l₂ := by
-  simpa only [ugetElem_eq_getElem, ← getElem_toList, uset, toList_set] using
+  simpa only [ugetElem_eq_getElem, getElem_eq_toList_getElem, uset, toList_set] using
     List.exists_of_set _
 
 end Array

src/Init/Data/BEq.lean

@@ -40,9 +40,6 @@ theorem BEq.symm [BEq α] [PartialEquivBEq α] {a b : α} : a == b → b == a :=
 theorem BEq.comm [BEq α] [PartialEquivBEq α] {a b : α} : (a == b) = (b == a) :=
   Bool.eq_iff_iff.2 ⟨BEq.symm, BEq.symm⟩
 
-theorem bne_comm [BEq α] [PartialEquivBEq α] {a b : α} : (a != b) = (b != a) := by
-  rw [bne, BEq.comm, bne]
-
 theorem BEq.symm_false [BEq α] [PartialEquivBEq α] {a b : α} : (a == b) = false → (b == a) = false :=
   BEq.comm (α := α) ▸ id
 

src/Init/Data/BitVec/Basic.lean

@@ -1,20 +1,19 @@
 /-
 Copyright (c) 2024 Lean FRO, LLC. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
-Authors: Joe Hendrix, Wojciech Nawrocki, Leonardo de Moura, Mario Carneiro, Alex Keizer, Harun Khan, Abdalrhman M Mohamed, Siddharth Bhat
+Authors: Joe Hendrix, Wojciech Nawrocki, Leonardo de Moura, Mario Carneiro, Alex Keizer, Harun Khan, Abdalrhman M Mohamed
 -/
 prelude
 import Init.Data.Fin.Basic
 import Init.Data.Nat.Bitwise.Lemmas
 import Init.Data.Nat.Power2
 import Init.Data.Int.Bitwise
-import Init.Data.BitVec.BasicAux
 
 /-!
-We define the basic algebraic structure of bitvectors. We choose the `Fin` representation over
-others for its relative efficiency (Lean has special support for `Nat`),  and the fact that bitwise
-operations on `Fin` are already defined. Some other possible representations are `List Bool`,
-`{ l : List Bool // l.length = w }`, `Fin w → Bool`.
+We define bitvectors. We choose the `Fin` representation over others for its relative efficiency
+(Lean has special support for `Nat`), alignment with `UIntXY` types which are also represented
+with `Fin`, and the fact that bitwise operations on `Fin` are already defined. Some other possible
+representations are `List Bool`, `{ l : List Bool // l.length = w }`, `Fin w → Bool`.
 
 We define many of the bitvector operations from the
 [`QF_BV` logic](https://smtlib.cs.uiowa.edu/logics-all.shtml#QF_BV).
@@ -23,12 +22,63 @@ of SMT-LIBv2.
 
 set_option linter.missingDocs true
 
+/--
+A bitvector of the specified width.
+
+This is represented as the underlying `Nat` number in both the runtime
+and the kernel, inheriting all the special support for `Nat`.
+-/
+structure BitVec (w : Nat) where
+  /-- Construct a `BitVec w` from a number less than `2^w`.
+  O(1), because we use `Fin` as the internal representation of a bitvector. -/
+  ofFin ::
+  /-- Interpret a bitvector as a number less than `2^w`.
+  O(1), because we use `Fin` as the internal representation of a bitvector. -/
+  toFin : Fin (2^w)
+
+/--
+Bitvectors have decidable equality. This should be used via the instance `DecidableEq (BitVec n)`.
+-/
+-- We manually derive the `DecidableEq` instances for `BitVec` because
+-- we want to have builtin support for bit-vector literals, and we
+-- need a name for this function to implement `canUnfoldAtMatcher` at `WHNF.lean`.
+def BitVec.decEq (x y : BitVec n) : Decidable (x = y) :=
+  match x, y with
+  | ⟨n⟩, ⟨m⟩ =>
+    if h : n = m then
+      isTrue (h ▸ rfl)
+    else
+      isFalse (fun h' => BitVec.noConfusion h' (fun h' => absurd h' h))
+
+instance : DecidableEq (BitVec n) := BitVec.decEq
+
 namespace BitVec
 
 section Nat
 
+/-- The `BitVec` with value `i`, given a proof that `i < 2^n`. -/
+@[match_pattern]
+protected def ofNatLt {n : Nat} (i : Nat) (p : i < 2^n) : BitVec n where
+  toFin := ⟨i, p⟩
+
+/-- The `BitVec` with value `i mod 2^n`. -/
+@[match_pattern]
+protected def ofNat (n : Nat) (i : Nat) : BitVec n where
+  toFin := Fin.ofNat' (2^n) i
+
+instance instOfNat : OfNat (BitVec n) i where ofNat := .ofNat n i
 instance natCastInst : NatCast (BitVec w) := ⟨BitVec.ofNat w⟩
 
+/-- Given a bitvector `x`, return the underlying `Nat`. This is O(1) because `BitVec` is a
+(zero-cost) wrapper around a `Nat`. -/
+protected def toNat (x : BitVec n) : Nat := x.toFin.val
+
+/-- Return the bound in terms of toNat. -/
+theorem isLt (x : BitVec w) : x.toNat < 2^w := x.toFin.isLt
+
+@[deprecated isLt (since := "2024-03-12")]
+theorem toNat_lt (x : BitVec n) : x.toNat < 2^n := x.isLt
+
 /-- Theorem for normalizing the bit vector literal representation. -/
 -- TODO: This needs more usage data to assess which direction the simp should go.
 @[simp, bv_toNat] theorem ofNat_eq_ofNat : @OfNat.ofNat (BitVec n) i _ = .ofNat n i := rfl
@@ -188,6 +238,22 @@ end repr_toString
 
 section arithmetic
 
+/--
+Addition for bit vectors. This can be interpreted as either signed or unsigned addition
+modulo `2^n`.
+
+SMT-Lib name: `bvadd`.
+-/
+protected def add (x y : BitVec n) : BitVec n := .ofNat n (x.toNat + y.toNat)
+instance : Add (BitVec n) := ⟨BitVec.add⟩
+
+/--
+Subtraction for bit vectors. This can be interpreted as either signed or unsigned subtraction
+modulo `2^n`.
+-/
+protected def sub (x y : BitVec n) : BitVec n := .ofNat n ((2^n - y.toNat) + x.toNat)
+instance : Sub (BitVec n) := ⟨BitVec.sub⟩
+
 /--
 Negation for bit vectors. This can be interpreted as either signed or unsigned negation
 modulo `2^n`.
@@ -203,8 +269,8 @@ Return the absolute value of a signed bitvector.
 protected def abs (x : BitVec n) : BitVec n := if x.msb then .neg x else x
 
 /--
-Multiplication for bit vectors. This can be interpreted as either signed or unsigned
-multiplication modulo `2^n`.
+Multiplication for bit vectors. This can be interpreted as either signed or unsigned negation
+modulo `2^n`.
 
 SMT-Lib name: `bvmul`.
 -/
@@ -321,6 +387,10 @@ SMT-Lib name: `bvult`.
 -/
 protected def ult (x y : BitVec n) : Bool := x.toNat < y.toNat
 
+instance : LT (BitVec n) where lt := (·.toNat < ·.toNat)
+instance (x y : BitVec n) : Decidable (x < y) :=
+  inferInstanceAs (Decidable (x.toNat < y.toNat))
+
 /--
 Unsigned less-than-or-equal-to for bit vectors.
 
@@ -328,6 +398,10 @@ SMT-Lib name: `bvule`.
 -/
 protected def ule (x y : BitVec n) : Bool := x.toNat ≤ y.toNat
 
+instance : LE (BitVec n) where le := (·.toNat ≤ ·.toNat)
+instance (x y : BitVec n) : Decidable (x ≤ y) :=
+  inferInstanceAs (Decidable (x.toNat ≤ y.toNat))
+
 /--
 Signed less-than for bit vectors.
 
@@ -351,17 +425,17 @@ end relations
 section cast
 
 /-- `cast eq x` embeds `x` into an equal `BitVec` type. -/
-@[inline] protected def cast (eq : n = m) (x : BitVec n) : BitVec m := .ofNatLt x.toNat (eq ▸ x.isLt)
+@[inline] def cast (eq : n = m) (x : BitVec n) : BitVec m := .ofNatLt x.toNat (eq ▸ x.isLt)
 
 @[simp] theorem cast_ofNat {n m : Nat} (h : n = m) (x : Nat) :
-    (BitVec.ofNat n x).cast h = BitVec.ofNat m x := by
+    cast h (BitVec.ofNat n x) = BitVec.ofNat m x := by
   subst h; rfl
 
 @[simp] theorem cast_cast {n m k : Nat} (h₁ : n = m) (h₂ : m = k) (x : BitVec n) :
-    (x.cast h₁).cast h₂ = x.cast (h₁ ▸ h₂) :=
+    cast h₂ (cast h₁ x) = cast (h₁ ▸ h₂) x :=
   rfl
 
-@[simp] theorem cast_eq {n : Nat} (h : n = n) (x : BitVec n) : x.cast h = x := rfl
+@[simp] theorem cast_eq {n : Nat} (h : n = n) (x : BitVec n) : cast h x = x := rfl
 
 /--
 Extraction of bits `start` to `start + len - 1` from a bit vector of size `n` to yield a
@@ -602,13 +676,6 @@ result of appending a single bit to the front in the naive implementation).
     That is, the new bit is the least significant bit. -/
 def concat {n} (msbs : BitVec n) (lsb : Bool) : BitVec (n+1) := msbs ++ (ofBool lsb)
 
-/--
-`x.shiftConcat b` shifts all bits of `x` to the left by `1` and sets the least significant bit to `b`.
-It is a non-dependent version of `concat` that does not change the total bitwidth.
--/
-def shiftConcat (x : BitVec n) (b : Bool) : BitVec n :=
-  (x.concat b).truncate n
-
 /-- Prepend a single bit to the front of a bitvector, using big endian order (see `append`).
     That is, the new bit is the most significant bit. -/
 def cons {n} (msb : Bool) (lsbs : BitVec n) : BitVec (n+1) :=
@@ -631,16 +698,6 @@ def twoPow (w : Nat) (i : Nat) : BitVec w := 1#w <<< i
 
 end bitwise
 
-/-- Compute a hash of a bitvector, combining 64-bit words using `mixHash`. -/
-def hash (bv : BitVec n) : UInt64 :=
-  if n ≤ 64 then
-    bv.toFin.val.toUInt64
-  else
-    mixHash (bv.toFin.val.toUInt64) (hash ((bv >>> 64).setWidth (n - 64)))
-
-instance : Hashable (BitVec n) where
-  hash := hash
-
 section normalization_eqs
 /-! We add simp-lemmas that rewrite bitvector operations into the equivalent notation -/
 @[simp] theorem append_eq (x : BitVec w) (y : BitVec v)   : BitVec.append x y = x ++ y        := rfl
@@ -654,8 +711,6 @@ section normalization_eqs
 @[simp] theorem add_eq (x y : BitVec w)                   : BitVec.add x y = x + y            := rfl
 @[simp] theorem sub_eq (x y : BitVec w)                   : BitVec.sub x y = x - y            := rfl
 @[simp] theorem mul_eq (x y : BitVec w)                   : BitVec.mul x y = x * y            := rfl
-@[simp] theorem udiv_eq (x y : BitVec w)                  : BitVec.udiv x y = x / y           := rfl
-@[simp] theorem umod_eq (x y : BitVec w)                  : BitVec.umod x y = x % y           := rfl
 @[simp] theorem zero_eq                                   : BitVec.zero n = 0#n               := rfl
 end normalization_eqs
 

src/Init/Data/BitVec/BasicAux.lean

@@ -1,52 +0,0 @@
-/-
-Copyright (c) 2024 Lean FRO, LLC. All rights reserved.
-Released under Apache 2.0 license as described in the file LICENSE.
-Authors: Joe Hendrix, Wojciech Nawrocki, Leonardo de Moura, Mario Carneiro, Alex Keizer, Harun Khan, Abdalrhman M Mohamed
--/
-prelude
-import Init.Data.Fin.Basic
-
-set_option linter.missingDocs true
-
-/-!
-This module exists to provide the very basic `BitVec` definitions required for
-`Init.Data.UInt.BasicAux`.
--/
-
-namespace BitVec
-
-section Nat
-
-/-- The `BitVec` with value `i mod 2^n`. -/
-@[match_pattern]
-protected def ofNat (n : Nat) (i : Nat) : BitVec n where
-  toFin := Fin.ofNat' (2^n) i
-
-instance instOfNat : OfNat (BitVec n) i where ofNat := .ofNat n i
-
-/-- Return the bound in terms of toNat. -/
-theorem isLt (x : BitVec w) : x.toNat < 2^w := x.toFin.isLt
-
-end Nat
-
-section arithmetic
-
-/--
-Addition for bit vectors. This can be interpreted as either signed or unsigned addition
-modulo `2^n`.
-
-SMT-Lib name: `bvadd`.
--/
-protected def add (x y : BitVec n) : BitVec n := .ofNat n (x.toNat + y.toNat)
-instance : Add (BitVec n) := ⟨BitVec.add⟩
-
-/--
-Subtraction for bit vectors. This can be interpreted as either signed or unsigned subtraction
-modulo `2^n`.
--/
-protected def sub (x y : BitVec n) : BitVec n := .ofNat n ((2^n - y.toNat) + x.toNat)
-instance : Sub (BitVec n) := ⟨BitVec.sub⟩
-
-end arithmetic
-
-end BitVec

src/Init/Data/BitVec/Bitblast.lean

@@ -1,7 +1,7 @@
 /-
 Copyright (c) 2024 Lean FRO, LLC. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
-Authors: Harun Khan, Abdalrhman M Mohamed, Joe Hendrix, Siddharth Bhat
+Authors: Harun Khan, Abdalrhman M Mohamed, Joe Hendrix
 -/
 prelude
 import Init.Data.BitVec.Folds
@@ -18,80 +18,6 @@ as vectors of bits into proofs about Lean `BitVec` values.
 The module is named for the bit-blasting operation in an SMT solver that converts bitvector
 expressions into expressions about individual bits in each vector.
 
-### Example: How bitblasting works for multiplication
-
-We explain how the lemmas here are used for bitblasting,
-by using multiplication as a prototypical example.
-Other bitblasters for other operations follow the same pattern.
-To bitblast a multiplication of the form `x * y`,
-we must unfold the above into a form that the SAT solver understands.
-
-We assume that the solver already knows how to bitblast addition.
-This is known to `bv_decide`, by exploiting the lemma `add_eq_adc`,
-which says that `x + y : BitVec w` equals `(adc x y false).2`,
-where `adc` builds an add-carry circuit in terms of the primitive operations
-(bitwise and, bitwise or, bitwise xor) that bv_decide already understands.
-In this way, we layer bitblasters on top of each other,
-by reducing the multiplication bitblaster to an addition operation.
-
-The core lemma is given by `getLsbD_mul`:
-
-```lean
- x y : BitVec w ⊢ (x * y).getLsbD i = (mulRec x y w).getLsbD i
-```
-
-Which says that the `i`th bit of `x * y` can be obtained by
-evaluating the `i`th bit of `(mulRec x y w)`.
-Once again, we assume that `bv_decide` knows how to implement `getLsbD`,
-given that `mulRec` can be understood by `bv_decide`.
-
-We write two lemmas to enable `bv_decide` to unfold `(mulRec x y w)`
-into a complete circuit, **when `w` is a known constant**`.
-This is given by two recurrence lemmas, `mulRec_zero_eq` and `mulRec_succ_eq`,
-which are applied repeatedly when the width is `0` and when the width is `w' + 1`:
-
-```lean
-mulRec_zero_eq :
-    mulRec x y 0 =
-      if y.getLsbD 0 then x else 0
-
-mulRec_succ_eq
-    mulRec x y (s + 1) =
-      mulRec x y s +
-      if y.getLsbD (s + 1) then (x <<< (s + 1)) else 0 := rfl
-```
-
-By repeatedly applying the lemmas `mulRec_zero_eq` and `mulRec_succ_eq`,
-one obtains a circuit for multiplication.
-Note that this circuit uses `BitVec.add`, `BitVec.getLsbD`, `BitVec.shiftLeft`.
-Here, `BitVec.add` and `BitVec.shiftLeft` are (recursively) bitblasted by `bv_decide`,
-using the lemmas `add_eq_adc` and `shiftLeft_eq_shiftLeftRec`,
-and `BitVec.getLsbD` is a primitive that `bv_decide` knows how to reduce to SAT.
-
-The two lemmas, `mulRec_zero_eq`, and `mulRec_succ_eq`,
-are used in `Std.Tactic.BVDecide.BVExpr.bitblast.blastMul`
-to prove the correctness of the circuit that is built by `bv_decide`.
-
-```lean
-def blastMul (aig : AIG BVBit) (input : AIG.BinaryRefVec aig w) : AIG.RefVecEntry BVBit w
-theorem denote_blastMul (aig : AIG BVBit) (lhs rhs : BitVec w) (assign : Assignment) :
-   ...
-   ⟦(blastMul aig input).aig, (blastMul aig input).vec[idx], assign.toAIGAssignment⟧
-     =
-   (lhs * rhs).getLsbD idx
-```
-
-The definition and theorem above are internal to `bv_decide`,
-and use `mulRec_{zero,succ}_eq` to prove that the circuit built by `bv_decide`
-computes the correct value for multiplication.
-
-To zoom out, therefore, we follow two steps:
-First, we prove bitvector lemmas to unfold a high-level operation (such as multiplication)
-into already bitblastable operations (such as addition and left shift).
-We then use these lemmas to prove the correctness of the circuit that `bv_decide` builds.
-
-We use this workflow to implement bitblasting for all SMT-LIB2 operations.
-
 ## Main results
 * `x + y : BitVec w` is `(adc x y false).2`.
 
@@ -174,30 +100,6 @@ theorem carry_succ (i : Nat) (x y : BitVec w) (c : Bool) :
     exact mod_two_pow_add_mod_two_pow_add_bool_lt_two_pow_succ ..
   cases x.toNat.testBit i <;> cases y.toNat.testBit i <;> (simp; omega)
 
-theorem carry_succ_one (i : Nat) (x : BitVec w) (h : 0 < w) :
-    carry (i+1) x (1#w) false = decide (∀ j ≤ i, x.getLsbD j = true) := by
-  induction i with
-  | zero => simp [carry_succ, h]
-  | succ i ih =>
-    rw [carry_succ, ih]
-    simp only [getLsbD_one, add_one_ne_zero, decide_false, Bool.and_false, atLeastTwo_false_mid]
-    cases hx : x.getLsbD (i+1)
-    case false =>
-      have : ∃ j ≤ i + 1, x.getLsbD j = false :=
-        ⟨i+1, by omega, hx⟩
-      simpa
-    case true =>
-      suffices
-          (∀ (j : Nat), j ≤ i → x.getLsbD j = true)
-          ↔ (∀ (j : Nat), j ≤ i + 1 → x.getLsbD j = true) by
-        simpa
-      constructor
-      · intro h j hj
-        rcases Nat.le_or_eq_of_le_succ hj with (hj' | rfl)
-        · apply h; assumption
-        · exact hx
-      · intro h j hj; apply h; omega
-
 /--
 If `x &&& y = 0`, then the carry bit `(x + y + 0)` is always `false` for any index `i`.
 Intuitively, this is because a carry is only produced when at least two of `x`, `y`, and the
@@ -249,7 +151,7 @@ theorem getLsbD_add_add_bool {i : Nat} (i_lt : i < w) (x y : BitVec w) (c : Bool
     [ Nat.testBit_mod_two_pow,
       Nat.testBit_mul_two_pow_add_eq,
       i_lt,
-      decide_true,
+      decide_True,
       Bool.true_and,
       Nat.add_assoc,
       Nat.add_left_comm (_%_) (_ * _) _,
@@ -262,17 +164,6 @@ theorem getLsbD_add {i : Nat} (i_lt : i < w) (x y : BitVec w) :
       (getLsbD x i ^^ (getLsbD y i ^^ carry i x y false)) := by
   simpa using getLsbD_add_add_bool i_lt x y false
 
-theorem getElem_add_add_bool {i : Nat} (i_lt : i < w) (x y : BitVec w) (c : Bool) :
-    (x + y + setWidth w (ofBool c))[i] =
-      (x[i] ^^ (y[i] ^^ carry i x y c)) := by
-  simp only [← getLsbD_eq_getElem]
-  rw [getLsbD_add_add_bool]
-  omega
-
-theorem getElem_add {i : Nat} (i_lt : i < w) (x y : BitVec w) :
-    (x + y)[i] = (x[i] ^^ (y[i] ^^ carry i x y false)) := by
-  simpa using getElem_add_add_bool i_lt x y false
-
 theorem adc_spec (x y : BitVec w) (c : Bool) :
     adc x y c = (carry w x y c, x + y + setWidth w (ofBool c)) := by
   simp only [adc]
@@ -291,21 +182,6 @@ theorem add_eq_adc (w : Nat) (x y : BitVec w) : x + y = (adc x y false).snd := b
 
 /-! ### add -/
 
-theorem getMsbD_add {i : Nat} {i_lt : i < w} {x y : BitVec w} :
-    getMsbD (x + y) i =
-      Bool.xor (getMsbD x i) (Bool.xor (getMsbD y i) (carry (w - 1 - i) x y false)) := by
-  simp [getMsbD, getLsbD_add, i_lt, show w - 1 - i < w by omega]
-
-theorem msb_add {w : Nat} {x y: BitVec w} :
-    (x + y).msb =
-      Bool.xor x.msb (Bool.xor y.msb (carry (w - 1) x y false)) := by
-  simp only [BitVec.msb, BitVec.getMsbD]
-  by_cases h : w ≤ 0
-  · simp [h, show w = 0 by omega]
-  · rw [getLsbD_add (x := x)]
-    simp [show w > 0 by omega]
-    omega
-
 /-- Adding a bitvector to its own complement yields the all ones bitpattern -/
 @[simp] theorem add_not_self (x : BitVec w) : x + ~~~x = allOnes w := by
   rw [add_eq_adc, adc, iunfoldr_replace (fun _ => false) (allOnes w)]
@@ -331,30 +207,6 @@ theorem add_eq_or_of_and_eq_zero {w : Nat} (x y : BitVec w)
       simp_all [hx]
     · by_cases hx : x.getLsbD i <;> simp_all [hx]
 
-/-! ### Sub-/
-
-theorem getLsbD_sub {i : Nat} {i_lt : i < w} {x y : BitVec w} :
-    (x - y).getLsbD i
-      = (x.getLsbD i ^^ ((~~~y + 1#w).getLsbD i ^^ carry i x (~~~y + 1#w) false)) := by
-  rw [sub_toAdd, BitVec.neg_eq_not_add, getLsbD_add]
-  omega
-
-theorem getMsbD_sub {i : Nat} {i_lt : i < w} {x y : BitVec w} :
-    (x - y).getMsbD i =
-      (x.getMsbD i ^^ ((~~~y + 1).getMsbD i ^^ carry (w - 1 - i) x (~~~y + 1) false)) := by
-  rw [sub_toAdd, neg_eq_not_add, getMsbD_add]
-  · rfl
-  · omega
-
-theorem getElem_sub {i : Nat} {x y : BitVec w} (h : i < w) :
-    (x - y)[i] = (x[i] ^^ ((~~~y + 1#w)[i] ^^ carry i x (~~~y + 1#w) false)) := by
-  simp [← getLsbD_eq_getElem, getLsbD_sub, h]
-
-theorem msb_sub {x y: BitVec w} :
-    (x - y).msb
-      = (x.msb ^^ ((~~~y + 1#w).msb ^^ carry (w - 1 - 0) x (~~~y + 1#w) false)) := by
-  simp [sub_toAdd, BitVec.neg_eq_not_add, msb_add]
-
 /-! ### Negation -/
 
 theorem bit_not_testBit (x : BitVec w) (i : Fin w) :
@@ -380,121 +232,6 @@ theorem bit_neg_eq_neg (x : BitVec w) : -x = (adc (((iunfoldr (fun (i : Fin w) c
     simp [← sub_toAdd, BitVec.sub_add_cancel]
   · simp [bit_not_testBit x _]
 
-/--
-Remember that negating a bitvector is equal to incrementing the complement
-by one, i.e., `-x = ~~~x + 1`. See also `neg_eq_not_add`.
-
-This computation has two crucial properties:
-- The least significant bit of `-x` is the same as the least significant bit of `x`, and
-- The `i+1`-th least significant bit of `-x` is the complement of the `i+1`-th bit of `x`, unless
-  all of the preceding bits are `false`, in which case the bit is equal to the `i+1`-th bit of `x`
--/
-theorem getLsbD_neg {i : Nat} {x : BitVec w} :
-    getLsbD (-x) i =
-      (getLsbD x i ^^ decide (i < w) && decide (∃ j < i, getLsbD x j = true)) := by
-  rw [neg_eq_not_add]
-  by_cases hi : i < w
-  · rw [getLsbD_add hi]
-    have : 0 < w := by omega
-    simp only [getLsbD_not, hi, decide_true, Bool.true_and, getLsbD_one, this, not_bne,
-      _root_.true_and, not_eq_eq_eq_not]
-    cases i with
-    | zero =>
-      have carry_zero : carry 0 ?x ?y false = false := by
-        simp [carry]; omega
-      simp [hi, carry_zero]
-    | succ =>
-      rw [carry_succ_one _ _ (by omega), ← Bool.xor_not, ← decide_not]
-      simp only [add_one_ne_zero, decide_false, getLsbD_not, and_eq_true, decide_eq_true_eq,
-        not_eq_eq_eq_not, Bool.not_true, false_bne, not_exists, _root_.not_and, not_eq_true,
-        bne_right_inj, decide_eq_decide]
-      constructor
-      · rintro h j hj; exact And.right <| h j (by omega)
-      · rintro h j hj; exact ⟨by omega, h j (by omega)⟩
-  · have h_ge : w ≤ i := by omega
-    simp [getLsbD_ge _ _ h_ge, h_ge, hi]
-
-theorem getElem_neg {i : Nat} {x : BitVec w} (h : i < w) :
-    (-x)[i] = (x[i] ^^ decide (∃ j < i, x.getLsbD j = true)) := by
-  simp [← getLsbD_eq_getElem, getLsbD_neg, h]
-
-theorem getMsbD_neg {i : Nat} {x : BitVec w} :
-    getMsbD (-x) i =
-      (getMsbD x i ^^ decide (∃ j < w, i < j ∧ getMsbD x j = true)) := by
-  simp only [getMsbD, getLsbD_neg, Bool.decide_and, Bool.and_eq_true, decide_eq_true_eq]
-  by_cases hi : i < w
-  case neg =>
-    simp [hi]; omega
-  case pos =>
-    have h₁ : w - 1 - i < w := by omega
-    simp only [hi, decide_true, h₁, Bool.true_and, Bool.bne_right_inj, decide_eq_decide]
-    constructor
-    · rintro ⟨j, hj, h⟩
-      refine ⟨w - 1 - j, by omega, by omega, by omega, _root_.cast ?_ h⟩
-      congr; omega
-    · rintro ⟨j, hj₁, hj₂, -, h⟩
-      exact ⟨w - 1 - j, by omega, h⟩
-
-theorem msb_neg {w : Nat} {x : BitVec w} :
-    (-x).msb = ((x != 0#w && x != intMin w) ^^ x.msb) := by
-  simp only [BitVec.msb, getMsbD_neg]
-  by_cases hmin : x = intMin _
-  case pos =>
-    have : (∃ j, j < w ∧ 0 < j ∧ 0 < w ∧ j = 0) ↔ False := by
-      simp; omega
-    simp [hmin, getMsbD_intMin, this]
-  case neg =>
-    by_cases hzero : x = 0#w
-    case pos => simp [hzero]
-    case neg =>
-      have w_pos : 0 < w := by
-        cases w
-        · rw [@of_length_zero x] at hzero
-          contradiction
-        · omega
-      suffices ∃ j, j < w ∧ 0 < j ∧ x.getMsbD j = true
-        by simp [show x != 0#w by simpa, show x != intMin w by simpa, this]
-      false_or_by_contra
-      rename_i getMsbD_x
-      simp only [not_exists, _root_.not_and, not_eq_true] at getMsbD_x
-      /- `getMsbD` says that all bits except the msb are `false` -/
-      cases hmsb : x.msb
-      case true =>
-        apply hmin
-        apply eq_of_getMsbD_eq
-        intro i hi
-        simp only [getMsbD_intMin, w_pos, decide_true, Bool.true_and]
-        cases i
-        case zero => exact hmsb
-        case succ => exact getMsbD_x _ hi (by omega)
-      case false =>
-        apply hzero
-        apply eq_of_getMsbD_eq
-        intro i hi
-        simp only [getMsbD_zero]
-        cases i
-        case zero => exact hmsb
-        case succ => exact getMsbD_x _ hi (by omega)
-
-/-! ### abs -/
-
-theorem msb_abs {w : Nat} {x : BitVec w} :
-    x.abs.msb = (decide (x = intMin w) && decide (0 < w)) := by
-  simp only [BitVec.abs, getMsbD_neg, ne_eq, decide_not, Bool.not_bne]
-  by_cases h₀ : 0 < w
-  · by_cases h₁ : x = intMin w
-    · simp [h₁, msb_intMin]
-    · simp only [neg_eq, h₁, decide_false]
-      by_cases h₂ : x.msb
-      · simp [h₂, msb_neg]
-        and_intros
-        · by_cases h₃ : x = 0#w
-          · simp [h₃] at h₂
-          · simp [h₃]
-        · simp [h₁]
-      · simp [h₂]
-  · simp [BitVec.msb, show w = 0 by omega]
-
 /-! ### Inequalities (le / lt) -/
 
 theorem ult_eq_not_carry (x y : BitVec w) : x.ult y = !carry w x (~~~y) true := by
@@ -573,19 +310,19 @@ theorem setWidth_setWidth_succ_eq_setWidth_setWidth_add_twoPow (x : BitVec w) (i
     setWidth w (x.setWidth (i + 1)) =
       setWidth w (x.setWidth i) + (x &&& twoPow w i) := by
   rw [add_eq_or_of_and_eq_zero]
-  · ext k h
-    simp only [getLsbD_setWidth, h, decide_true, Bool.true_and, getLsbD_or, getLsbD_and]
+  · ext k
+    simp only [getLsbD_setWidth, Fin.is_lt, decide_True, Bool.true_and, getLsbD_or, getLsbD_and]
     by_cases hik : i = k
     · subst hik
-      simp [h]
-    · simp only [getLsbD_twoPow, hik, decide_false, Bool.and_false, Bool.or_false]
+      simp
+    · simp only [getLsbD_twoPow, hik, decide_False, Bool.and_false, Bool.or_false]
       by_cases hik' : k < (i + 1)
       · have hik'' : k < i := by omega
         simp [hik', hik'']
       · have hik'' : ¬ (k < i) := by omega
         simp [hik', hik'']
   · ext k
-    simp only [and_twoPow, getLsbD_and, getLsbD_setWidth, Fin.is_lt, decide_true, Bool.true_and,
+    simp only [and_twoPow, getLsbD_and, getLsbD_setWidth, Fin.is_lt, decide_True, Bool.true_and,
       getLsbD_zero, and_eq_false_imp, and_eq_true, decide_eq_true_eq, and_imp]
     by_cases hi : x.getLsbD i <;> simp [hi] <;> omega
 
@@ -631,10 +368,6 @@ theorem getLsbD_mul (x y : BitVec w) (i : Nat) :
   · simp
   · omega
 
-theorem getElem_mul {x y : BitVec w} {i : Nat} (h : i < w) :
-    (x * y)[i] = (mulRec x y w)[i] := by
-  simp [mulRec_eq_mul_signExtend_setWidth]
-
 /-! ## shiftLeft recurrence for bitblasting -/
 
 /--
@@ -705,385 +438,6 @@ theorem shiftLeft_eq_shiftLeftRec (x : BitVec w₁) (y : BitVec w₂) :
   · simp [of_length_zero]
   · simp [shiftLeftRec_eq]
 
-/-! # udiv/urem recurrence for bitblasting
-
-In order to prove the correctness of the division algorithm on the integers,
-one shows that `n.div d = q` and `n.mod d = r` iff `n = d * q + r` and `0 ≤ r < d`.
-Mnemonic: `n` is the numerator, `d` is the denominator, `q` is the quotient, and `r` the remainder.
-
-This *uniqueness of decomposition* is not true for bitvectors.
-For `n = 0, d = 3, w = 3`, we can write:
-- `0 = 0 * 3 + 0` (`q = 0`, `r = 0 < 3`.)
-- `0 = 2 * 3 + 2 = 6 + 2 ≃ 0 (mod 8)` (`q = 2`, `r = 2 < 3`).
-
-Such examples can be created by choosing different `(q, r)` for a fixed `(d, n)`
-such that `(d * q + r)` overflows and wraps around to equal `n`.
-
-This tells us that the division algorithm must have more restrictions than just the ones
-we have for integers. These restrictions are captured in `DivModState.Lawful`.
-The key idea is to state the relationship in terms of the toNat values of {n, d, q, r}.
-If the division equation `d.toNat * q.toNat + r.toNat = n.toNat` holds,
-then `n.udiv d = q` and `n.umod d = r`.
-
-Following this, we implement the division algorithm by repeated shift-subtract.
-
-References:
-- Fast 32-bit Division on the DSP56800E: Minimized nonrestoring division algorithm by David Baca
-- Bitwuzla sources for bitblasting.h
--/
-
-private theorem Nat.div_add_eq_left_of_lt {x y z : Nat} (hx : z ∣ x) (hy : y < z) (hz : 0 < z) :
-    (x + y) / z = x / z := by
-  refine Nat.div_eq_of_lt_le ?lo ?hi
-  · apply Nat.le_trans
-    · exact div_mul_le_self x z
-    · omega
-  · simp only [succ_eq_add_one, Nat.add_mul, Nat.one_mul]
-    apply Nat.add_lt_add_of_le_of_lt
-    · apply Nat.le_of_eq
-      exact (Nat.div_eq_iff_eq_mul_left hz hx).mp rfl
-    · exact hy
-
-/-- If the division equation `d.toNat * q.toNat + r.toNat = n.toNat` holds,
-then `n.udiv d = q`. -/
-theorem udiv_eq_of_mul_add_toNat {d n q r : BitVec w} (hd : 0 < d)
-    (hrd : r < d)
-    (hdqnr : d.toNat * q.toNat + r.toNat = n.toNat) :
-    n / d = q := by
-  apply BitVec.eq_of_toNat_eq
-  rw [toNat_udiv]
-  replace hdqnr : (d.toNat * q.toNat + r.toNat) / d.toNat = n.toNat / d.toNat := by
-    simp [hdqnr]
-  rw [Nat.div_add_eq_left_of_lt] at hdqnr
-  · rw [← hdqnr]
-    exact mul_div_right q.toNat hd
-  · exact Nat.dvd_mul_right d.toNat q.toNat
-  · exact hrd
-  · exact hd
-
-/-- If the division equation `d.toNat * q.toNat + r.toNat = n.toNat` holds,
-then `n.umod d = r`. -/
-theorem umod_eq_of_mul_add_toNat {d n q r : BitVec w} (hrd : r < d)
-    (hdqnr : d.toNat * q.toNat + r.toNat = n.toNat) :
-    n % d = r := by
-  apply BitVec.eq_of_toNat_eq
-  rw [toNat_umod]
-  replace hdqnr : (d.toNat * q.toNat + r.toNat) % d.toNat = n.toNat % d.toNat := by
-    simp [hdqnr]
-  rw [Nat.add_mod, Nat.mul_mod_right] at hdqnr
-  simp only [Nat.zero_add, mod_mod] at hdqnr
-  replace hrd : r.toNat < d.toNat := by
-    simpa [BitVec.lt_def] using hrd
-  rw [Nat.mod_eq_of_lt hrd] at hdqnr
-  simp [hdqnr]
-
-/-! ### DivModState -/
-
-/-- `DivModState` is a structure that maintains the state of recursive `divrem` calls. -/
-structure DivModState (w : Nat) : Type where
-  /-- The number of bits in the numerator that are not yet processed -/
-  wn : Nat
-  /-- The number of bits in the remainder (and quotient) -/
-  wr : Nat
-  /-- The current quotient. -/
-  q : BitVec w
-  /-- The current remainder. -/
-  r : BitVec w
-
-
-/-- `DivModArgs` contains the arguments to a `divrem` call which remain constant throughout
-execution. -/
-structure DivModArgs (w : Nat) where
-  /-- the numerator (aka, dividend) -/
-  n : BitVec w
-  /-- the denumerator (aka, divisor)-/
-  d : BitVec w
-
-/-- A `DivModState` is lawful if the remainder width `wr` plus the numerator width `wn` equals `w`,
-and the bitvectors `r` and `n` have values in the bounds given by bitwidths `wr`, resp. `wn`.
-
-This is a proof engineering choice: an alternative world could have been
-`r : BitVec wr` and `n : BitVec wn`, but this required much more dependent typing coercions.
-
-Instead, we choose to declare all involved bitvectors as length `w`, and then prove that
-the values are within their respective bounds.
-
-We start with `wn = w` and `wr = 0`, and then in each step, we decrement `wn` and increment `wr`.
-In this way, we grow a legal remainder in each loop iteration.
--/
-structure DivModState.Lawful {w : Nat} (args : DivModArgs w) (qr : DivModState w) : Prop where
-  /-- The sum of widths of the dividend and remainder is `w`. -/
-  hwrn : qr.wr + qr.wn = w
-  /-- The denominator is positive. -/
-  hdPos : 0 < args.d
-  /-- The remainder is strictly less than the denominator. -/
-  hrLtDivisor : qr.r.toNat < args.d.toNat
-  /-- The remainder is morally a `Bitvec wr`, and so has value less than `2^wr`. -/
-  hrWidth : qr.r.toNat < 2^qr.wr
-  /-- The quotient is morally a `Bitvec wr`, and so has value less than `2^wr`. -/
-  hqWidth : qr.q.toNat < 2^qr.wr
-  /-- The low `(w - wn)` bits of `n` obey the invariant for division. -/
-  hdiv : args.n.toNat >>> qr.wn = args.d.toNat * qr.q.toNat + qr.r.toNat
-
-/-- A lawful DivModState implies `w > 0`. -/
-def DivModState.Lawful.hw {args : DivModArgs w} {qr : DivModState w}
-    {h : DivModState.Lawful args qr} : 0 < w := by
-  have hd := h.hdPos
-  rcases w with rfl | w
-  · have hcontra : args.d = 0#0 := by apply Subsingleton.elim
-    rw [hcontra] at hd
-    simp at hd
-  · omega
-
-/-- An initial value with both `q, r = 0`. -/
-def DivModState.init (w : Nat) : DivModState w := {
-  wn := w
-  wr := 0
-  q := 0#w
-  r := 0#w
-}
-
-/-- The initial state is lawful. -/
-def DivModState.lawful_init {w : Nat} (args : DivModArgs w) (hd : 0#w < args.d) :
-    DivModState.Lawful args (DivModState.init w) := by
-  simp only [BitVec.DivModState.init]
-  exact {
-    hwrn := by simp only; omega,
-    hdPos := by assumption
-    hrLtDivisor := by simp [BitVec.lt_def] at hd ⊢; assumption
-    hrWidth := by simp [DivModState.init],
-    hqWidth := by simp [DivModState.init],
-    hdiv := by
-      simp only [DivModState.init, toNat_ofNat, zero_mod, Nat.mul_zero, Nat.add_zero];
-      rw [Nat.shiftRight_eq_div_pow]
-      apply Nat.div_eq_of_lt args.n.isLt
-  }
-
-/--
-A lawful DivModState with a fully consumed dividend (`wn = 0`) witnesses that the
-quotient has been correctly computed.
--/
-theorem DivModState.udiv_eq_of_lawful {n d : BitVec w} {qr : DivModState w}
-    (h_lawful : DivModState.Lawful {n, d} qr)
-    (h_final  : qr.wn = 0) :
-    n / d = qr.q := by
-  apply udiv_eq_of_mul_add_toNat h_lawful.hdPos h_lawful.hrLtDivisor
-  have hdiv := h_lawful.hdiv
-  simp only [h_final] at *
-  omega
-
-/--
-A lawful DivModState with a fully consumed dividend (`wn = 0`) witnesses that the
-remainder has been correctly computed.
--/
-theorem DivModState.umod_eq_of_lawful {qr : DivModState w}
-    (h : DivModState.Lawful {n, d} qr)
-    (h_final  : qr.wn = 0) :
-    n % d = qr.r := by
-  apply umod_eq_of_mul_add_toNat h.hrLtDivisor
-  have hdiv := h.hdiv
-  simp only [shiftRight_zero] at hdiv
-  simp only [h_final] at *
-  exact hdiv.symm
-
-/-! ### DivModState.Poised -/
-
-/--
-A `Poised` DivModState is a state which is `Lawful` and furthermore, has at least
-one numerator bit left to process `(0 < wn)`
-
-The input to the shift subtractor is a legal input to `divrem`, and we also need to have an
-input bit to perform shift subtraction on, and thus we need `0 < wn`.
--/
-structure DivModState.Poised {w : Nat} (args : DivModArgs w) (qr : DivModState w)
-  extends DivModState.Lawful args qr : Type where
-  /-- Only perform a round of shift-subtract if we have dividend bits. -/
-  hwn_lt : 0 < qr.wn
-
-/--
-In the shift subtract input, the dividend is at least one bit long (`wn > 0`), so
-the remainder has bits to be computed (`wr < w`).
--/
-def DivModState.wr_lt_w {qr : DivModState w} (h : qr.Poised args) : qr.wr < w := by
-  have hwrn := h.hwrn
-  have hwn_lt := h.hwn_lt
-  omega
-
-/-! ### Division shift subtractor -/
-
-/--
-One round of the division algorithm, that tries to perform a subtract shift.
-Note that this should only be called when `r.msb = false`, so we will not overflow.
--/
-def divSubtractShift (args : DivModArgs w) (qr : DivModState w) : DivModState w :=
-  let {n, d} := args
-  let wn := qr.wn - 1
-  let wr := qr.wr + 1
-  let r' := shiftConcat qr.r (n.getLsbD wn)
-  if r' < d then {
-    q := qr.q.shiftConcat false, -- If `r' < d`, then we do not have a quotient bit.
-    r := r'
-    wn, wr
-  } else {
-    q := qr.q.shiftConcat true, -- Otherwise, `r' ≥ d`, and we have a quotient bit.
-    r := r' - d -- we subtract to maintain the invariant that `r < d`.
-    wn, wr
-  }
-
-/-- The value of shifting right by `wn - 1` equals shifting by `wn` and grabbing the lsb at `(wn - 1)`. -/
-theorem DivModState.toNat_shiftRight_sub_one_eq
-    {args : DivModArgs w} {qr : DivModState w} (h : qr.Poised args) :
-    args.n.toNat >>> (qr.wn - 1)
-    = (args.n.toNat >>> qr.wn) * 2 + (args.n.getLsbD (qr.wn - 1)).toNat := by
-  show BitVec.toNat (args.n >>> (qr.wn - 1)) = _
-  have {..} := h -- break the structure down for `omega`
-  rw [shiftRight_sub_one_eq_shiftConcat args.n h.hwn_lt]
-  rw [toNat_shiftConcat_eq_of_lt (k := w - qr.wn)]
-  · simp
-  · omega
-  · apply BitVec.toNat_ushiftRight_lt
-    omega
-
-/--
-This is used when proving the correctness of the division algorithm,
-where we know that `r < d`.
-We then want to show that `((r.shiftConcat b) - d) < d` as the loop invariant.
-In arithmetic, this is the same as showing that
-`r * 2 + 1 - d < d`, which this theorem establishes.
--/
-private theorem two_mul_add_sub_lt_of_lt_of_lt_two (h : a < x) (hy : y < 2) :
-    2 * a + y - x < x := by omega
-
-/-- We show that the output of `divSubtractShift` is lawful, which tells us that it
-obeys the division equation. -/
-theorem lawful_divSubtractShift (qr : DivModState w) (h : qr.Poised args) :
-    DivModState.Lawful args (divSubtractShift args qr) := by
-  rcases args with ⟨n, d⟩
-  simp only [divSubtractShift, decide_eq_true_eq]
-  -- We add these hypotheses for `omega` to find them later.
-  have ⟨⟨hrwn, hd, hrd, hr, hn, hrnd⟩, hwn_lt⟩ := h
-  have : d.toNat * (qr.q.toNat * 2) = d.toNat * qr.q.toNat * 2 := by rw [Nat.mul_assoc]
-  by_cases rltd : shiftConcat qr.r (n.getLsbD (qr.wn - 1)) < d
-  · simp only [rltd, ↓reduceIte]
-    constructor <;> try bv_omega
-    case pos.hrWidth => apply toNat_shiftConcat_lt_of_lt <;> omega
-    case pos.hqWidth => apply toNat_shiftConcat_lt_of_lt <;> omega
-    case pos.hdiv =>
-      simp [qr.toNat_shiftRight_sub_one_eq h, h.hdiv, this,
-        toNat_shiftConcat_eq_of_lt (qr.wr_lt_w h) h.hrWidth,
-        toNat_shiftConcat_eq_of_lt (qr.wr_lt_w h) h.hqWidth]
-      omega
-  · simp only [rltd, ↓reduceIte]
-    constructor <;> try bv_omega
-    case neg.hrLtDivisor =>
-      simp only [lt_def, Nat.not_lt] at rltd
-      rw [BitVec.toNat_sub_of_le rltd,
-        toNat_shiftConcat_eq_of_lt (hk := qr.wr_lt_w h) (hx := h.hrWidth),
-        Nat.mul_comm]
-      apply two_mul_add_sub_lt_of_lt_of_lt_two <;> bv_omega
-    case neg.hrWidth =>
-      simp only
-      have hdr' : d ≤ (qr.r.shiftConcat (n.getLsbD (qr.wn - 1))) :=
-        BitVec.not_lt_iff_le.mp rltd
-      have hr' : ((qr.r.shiftConcat (n.getLsbD (qr.wn - 1)))).toNat < 2 ^ (qr.wr + 1) := by
-        apply toNat_shiftConcat_lt_of_lt <;> bv_omega
-      rw [BitVec.toNat_sub_of_le hdr']
-      omega
-    case neg.hqWidth =>
-      apply toNat_shiftConcat_lt_of_lt <;> omega
-    case neg.hdiv =>
-      have rltd' := (BitVec.not_lt_iff_le.mp rltd)
-      simp only [qr.toNat_shiftRight_sub_one_eq h,
-        BitVec.toNat_sub_of_le rltd',
-        toNat_shiftConcat_eq_of_lt (qr.wr_lt_w h) h.hrWidth]
-      simp only [BitVec.le_def,
-        toNat_shiftConcat_eq_of_lt (qr.wr_lt_w h) h.hrWidth] at rltd'
-      simp only [toNat_shiftConcat_eq_of_lt (qr.wr_lt_w h) h.hqWidth, h.hdiv, Nat.mul_add]
-      bv_omega
-
-/-! ### Core division algorithm circuit -/
-
-/-- A recursive definition of division for bitblasting, in terms of a shift-subtraction circuit. -/
-def divRec {w : Nat} (m : Nat) (args : DivModArgs w) (qr : DivModState w) :
-    DivModState w :=
-  match m with
-  | 0 => qr
-  | m + 1 => divRec m args <| divSubtractShift args qr
-
-@[simp]
-theorem divRec_zero (qr : DivModState w) :
-    divRec 0 args qr = qr := rfl
-
-@[simp]
-theorem divRec_succ (m : Nat) (args : DivModArgs w) (qr : DivModState w) :
-    divRec (m + 1) args qr =
-      divRec m args (divSubtractShift args qr) := rfl
-
-/-- The output of `divRec` is a lawful state -/
-theorem lawful_divRec {args : DivModArgs w} {qr : DivModState w}
-    (h : DivModState.Lawful args qr) :
-    DivModState.Lawful args (divRec qr.wn args qr) := by
-  generalize hm : qr.wn = m
-  induction m generalizing qr
-  case zero =>
-    exact h
-  case succ wn' ih =>
-    simp only [divRec_succ]
-    apply ih
-    · apply lawful_divSubtractShift
-      constructor
-      · assumption
-      · omega
-    · simp only [divSubtractShift, hm]
-      split <;> rfl
-
-/-- The output of `divRec` has no more bits left to process (i.e., `wn = 0`) -/
-@[simp]
-theorem wn_divRec (args : DivModArgs w) (qr : DivModState w) :
-    (divRec qr.wn args qr).wn = 0 := by
-  generalize hm : qr.wn = m
-  induction m generalizing qr
-  case zero =>
-    assumption
-  case succ wn' ih =>
-    apply ih
-    simp only [divSubtractShift, hm]
-    split <;> rfl
-
-/-- The result of `udiv` agrees with the result of the division recurrence. -/
-theorem udiv_eq_divRec (hd : 0#w < d) :
-    let out := divRec w {n, d} (DivModState.init w)
-    n / d = out.q := by
-  have := DivModState.lawful_init {n, d} hd
-  have := lawful_divRec this
-  apply DivModState.udiv_eq_of_lawful this (wn_divRec ..)
-
-/-- The result of `umod` agrees with the result of the division recurrence. -/
-theorem umod_eq_divRec (hd : 0#w < d) :
-    let out := divRec w {n, d} (DivModState.init w)
-    n % d = out.r := by
-  have := DivModState.lawful_init {n, d} hd
-  have := lawful_divRec this
-  apply DivModState.umod_eq_of_lawful this (wn_divRec ..)
-
-theorem divRec_succ' (m : Nat) (args : DivModArgs w) (qr : DivModState w) :
-    divRec (m+1) args qr =
-    let wn := qr.wn - 1
-    let wr := qr.wr + 1
-    let r' := shiftConcat qr.r (args.n.getLsbD wn)
-    let input : DivModState _ :=
-      if r' < args.d then {
-        q := qr.q.shiftConcat false,
-        r := r'
-        wn, wr
-      } else {
-        q := qr.q.shiftConcat true,
-        r := r' - args.d
-        wn, wr
-      }
-    divRec m args input := by
-  simp [divRec_succ, divSubtractShift]
-
 /- ### Arithmetic shift right (sshiftRight) recurrence -/
 
 /--
@@ -1100,8 +454,8 @@ def sshiftRightRec (x : BitVec w₁) (y : BitVec w₂) (n : Nat) : BitVec w₁ :
 
 @[simp]
 theorem sshiftRightRec_zero_eq (x : BitVec w₁) (y : BitVec w₂) :
-    sshiftRightRec x y 0 = x.sshiftRight' (y &&& twoPow w₂ 0) := by
-  simp only [sshiftRightRec]
+    sshiftRightRec x y 0 = x.sshiftRight' (y &&& 1#w₂) := by
+  simp only [sshiftRightRec, twoPow_zero]
 
 @[simp]
 theorem sshiftRightRec_succ_eq (x : BitVec w₁) (y : BitVec w₂) (n : Nat) :

src/Init/Data/BitVec/Folds.lean

@@ -65,7 +65,7 @@ theorem iunfoldr_getLsbD' {f : Fin w → α → α × Bool} (state : Nat → α)
     intro
     apply And.intro
     · intro i
-      have := Fin.pos i
+      have := Fin.size_pos i
       contradiction
     · rfl
   case step =>

src/Init/Data/Bool.lean

@@ -238,8 +238,8 @@ theorem not_bne_not : ∀ (x y : Bool), ((!x) != (!y)) = (x != y) := by simp
 @[simp] theorem bne_assoc : ∀ (x y z : Bool), ((x != y) != z) = (x != (y != z)) := by decide
 instance : Std.Associative (· != ·) := ⟨bne_assoc⟩
 
-@[simp] theorem bne_right_inj  : ∀ {x y z : Bool}, (x != y) = (x != z) ↔ y = z := by decide
-@[simp] theorem bne_left_inj : ∀ {x y z : Bool}, (x != z) = (y != z) ↔ x = y := by decide
+@[simp] theorem bne_left_inj  : ∀ {x y z : Bool}, (x != y) = (x != z) ↔ y = z := by decide
+@[simp] theorem bne_right_inj : ∀ {x y z : Bool}, (x != z) = (y != z) ↔ x = y := by decide
 
 theorem eq_not_of_ne : ∀ {x y : Bool}, x ≠ y → x = !y := by decide
 
@@ -295,9 +295,9 @@ theorem xor_right_comm : ∀ (x y z : Bool), ((x ^^ y) ^^ z) = ((x ^^ z) ^^ y) :
 
 theorem xor_assoc : ∀ (x y z : Bool), ((x ^^ y) ^^ z) = (x ^^ (y ^^ z)) := bne_assoc
 
-theorem xor_right_inj : ∀ {x y z : Bool}, (x ^^ y) = (x ^^ z) ↔ y = z := bne_right_inj
+theorem xor_left_inj : ∀ {x y z : Bool}, (x ^^ y) = (x ^^ z) ↔ y = z := bne_left_inj
 
-theorem xor_left_inj : ∀ {x y z : Bool}, (x ^^ z) = (y ^^ z) ↔ x = y := bne_left_inj
+theorem xor_right_inj : ∀ {x y z : Bool}, (x ^^ z) = (y ^^ z) ↔ x = y := bne_right_inj
 
 /-! ### le/lt -/
 
@@ -368,14 +368,13 @@ theorem and_or_inj_left_iff :
 /-- convert a `Bool` to a `Nat`, `false -> 0`, `true -> 1` -/
 def toNat (b : Bool) : Nat := cond b 1 0
 
-@[simp, bv_toNat] theorem toNat_false : false.toNat = 0 := rfl
+@[simp] theorem toNat_false : false.toNat = 0 := rfl
 
-@[simp, bv_toNat] theorem toNat_true : true.toNat = 1 := rfl
+@[simp] theorem toNat_true : true.toNat = 1 := rfl
 
 theorem toNat_le (c : Bool) : c.toNat ≤ 1 := by
   cases c <;> trivial
 
-@[bv_toNat]
 theorem toNat_lt (b : Bool) : b.toNat < 2 :=
   Nat.lt_succ_of_le (toNat_le _)
 
@@ -384,15 +383,6 @@ theorem toNat_lt (b : Bool) : b.toNat < 2 :=
 @[simp] theorem toNat_eq_one  {b : Bool} : b.toNat = 1 ↔ b = true := by
   cases b <;> simp
 
-/-! ## toInt -/
-
-/-- convert a `Bool` to an `Int`, `false -> 0`, `true -> 1` -/
-def toInt (b : Bool) : Int := cond b 1 0
-
-@[simp] theorem toInt_false : false.toInt = 0 := rfl
-
-@[simp] theorem toInt_true : true.toInt = 1 := rfl
-
 /-! ### ite -/
 
 @[simp] theorem if_true_left  (p : Prop) [h : Decidable p] (f : Bool) :

src/Init/Data/ByteArray/Basic.lean

@@ -42,7 +42,7 @@ def usize (a : @& ByteArray) : USize :=
   a.size.toUSize
 
 @[extern "lean_byte_array_uget"]
-def uget : (a : @& ByteArray) → (i : USize) → (h : i.toNat < a.size := by get_elem_tactic) → UInt8
+def uget : (a : @& ByteArray) → (i : USize) → i.toNat < a.size → UInt8
   | ⟨bs⟩, i, h => bs[i]
 
 @[extern "lean_byte_array_get"]
@@ -50,11 +50,11 @@ def get! : (@& ByteArray) → (@& Nat) → UInt8
   | ⟨bs⟩, i => bs.get! i
 
 @[extern "lean_byte_array_fget"]
-def get : (a : @& ByteArray) → (i : @& Nat) → (h : i < a.size := by get_elem_tactic) → UInt8
-  | ⟨bs⟩, i, _ => bs[i]
+def get : (a : @& ByteArray) → (@& Fin a.size) → UInt8
+  | ⟨bs⟩, i => bs.get i
 
 instance : GetElem ByteArray Nat UInt8 fun xs i => i < xs.size where
-  getElem xs i h := xs.get i
+  getElem xs i h := xs.get ⟨i, h⟩
 
 instance : GetElem ByteArray USize UInt8 fun xs i => i.val < xs.size where
   getElem xs i h := xs.uget i h
@@ -64,11 +64,11 @@ def set! : ByteArray → (@& Nat) → UInt8 → ByteArray
   | ⟨bs⟩, i, b => ⟨bs.set! i b⟩
 
 @[extern "lean_byte_array_fset"]
-def set : (a : ByteArray) → (i : @& Nat) → UInt8 → (h : i < a.size := by get_elem_tactic) → ByteArray
-  | ⟨bs⟩, i, b, h => ⟨bs.set i b h⟩
+def set : (a : ByteArray) → (@& Fin a.size) → UInt8 → ByteArray
+  | ⟨bs⟩, i, b => ⟨bs.set i b⟩
 
 @[extern "lean_byte_array_uset"]
-def uset : (a : ByteArray) → (i : USize) → UInt8 → (h : i.toNat < a.size := by get_elem_tactic) → ByteArray
+def uset : (a : ByteArray) → (i : USize) → UInt8 → i.toNat < a.size → ByteArray
   | ⟨bs⟩, i, v, h => ⟨bs.uset i v h⟩
 
 @[extern "lean_byte_array_hash"]
@@ -108,18 +108,8 @@ def toList (bs : ByteArray) : List UInt8 :=
 
 @[inline] def findIdx? (a : ByteArray) (p : UInt8 → Bool) (start := 0) : Option Nat :=
   let rec @[specialize] loop (i : Nat) :=
-    if h : i < a.size then
-      if p a[i] then some i else loop (i+1)
-    else
-      none
-    termination_by a.size - i
-    decreasing_by decreasing_trivial_pre_omega
-  loop start
-
-@[inline] def findFinIdx? (a : ByteArray) (p : UInt8 → Bool) (start := 0) : Option (Fin a.size) :=
-  let rec @[specialize] loop (i : Nat) :=
-    if h : i < a.size then
-      if p a[i] then some ⟨i, h⟩ else loop (i+1)
+    if i < a.size then
+      if p (a.get! i) then some i else loop (i+1)
     else
       none
     termination_by a.size - i
@@ -154,7 +144,7 @@ protected def forIn {β : Type v} {m : Type v → Type w} [Monad m] (as : ByteAr
       have h' : i < as.size            := Nat.lt_of_lt_of_le (Nat.lt_succ_self i) h
       have : as.size - 1 < as.size     := Nat.sub_lt (Nat.zero_lt_of_lt h') (by decide)
       have : as.size - 1 - i < as.size := Nat.lt_of_le_of_lt (Nat.sub_le (as.size - 1) i) this
-      match (← f as[as.size - 1 - i] b) with
+      match (← f (as.get ⟨as.size - 1 - i, this⟩) b) with
       | ForInStep.done b  => pure b
       | ForInStep.yield b => loop i (Nat.le_of_lt h') b
   loop as.size (Nat.le_refl _) b
@@ -188,7 +178,7 @@ def foldlM {β : Type v} {m : Type v → Type w} [Monad m] (f : β → UInt8 →
         match i with
         | 0    => pure b
         | i'+1 =>
-          loop i' (j+1) (← f b as[j])
+          loop i' (j+1) (← f b (as.get ⟨j, Nat.lt_of_lt_of_le hlt h⟩))
       else
         pure b
     loop (stop - start) start init
@@ -255,7 +245,7 @@ On an invalid position, returns `(default : UInt8)`. -/
 @[inline]
 def curr : Iterator → UInt8
   | ⟨arr, i⟩ =>
-    if h : i < arr.size then
+    if h:i < arr.size then
       arr[i]'h
     else
       default

src/Init/Data/Channel.lean

@@ -8,8 +8,6 @@ import Init.Data.Queue
 import Init.System.Promise
 import Init.System.Mutex
 
-set_option linter.deprecated false
-
 namespace IO
 
 /--
@@ -17,7 +15,6 @@ Internal state of an `Channel`.
 
 We maintain the invariant that at all times either `consumers` or `values` is empty.
 -/
-@[deprecated "Use Std.Channel.State from Std.Sync.Channel instead" (since := "2024-12-02")]
 structure Channel.State (α : Type) where
   values : Std.Queue α := ∅
   consumers : Std.Queue (Promise (Option α)) := ∅
@@ -30,14 +27,12 @@ FIFO channel with unbounded buffer, where `recv?` returns a `Task`.
 A channel can be closed.  Once it is closed, all `send`s are ignored, and
 `recv?` returns `none` once the queue is empty.
 -/
-@[deprecated "Use Std.Channel from Std.Sync.Channel instead" (since := "2024-12-02")]
 def Channel (α : Type) : Type := Mutex (Channel.State α)
 
 instance : Nonempty (Channel α) :=
   inferInstanceAs (Nonempty (Mutex _))
 
 /-- Creates a new `Channel`. -/
-@[deprecated "Use Std.Channel.new from Std.Sync.Channel instead" (since := "2024-12-02")]
 def Channel.new : BaseIO (Channel α) :=
   Mutex.new {}
 
@@ -46,7 +41,6 @@ Sends a message on an `Channel`.
 
 This function does not block.
 -/
-@[deprecated "Use Std.Channel.send from Std.Sync.Channel instead" (since := "2024-12-02")]
 def Channel.send (ch : Channel α) (v : α) : BaseIO Unit :=
   ch.atomically do
     let st ← get
@@ -60,7 +54,6 @@ def Channel.send (ch : Channel α) (v : α) : BaseIO Unit :=
 /--
 Closes an `Channel`.
 -/
-@[deprecated "Use Std.Channel.close from Std.Sync.Channel instead" (since := "2024-12-02")]
 def Channel.close (ch : Channel α) : BaseIO Unit :=
   ch.atomically do
     let st ← get
@@ -74,7 +67,6 @@ Every message is only received once.
 
 Returns `none` if the channel is closed and the queue is empty.
 -/
-@[deprecated "Use Std.Channel.recv? from Std.Sync.Channel instead" (since := "2024-12-02")]
 def Channel.recv? (ch : Channel α) : BaseIO (Task (Option α)) :=
   ch.atomically do
     let st ← get
@@ -93,7 +85,6 @@ def Channel.recv? (ch : Channel α) : BaseIO (Task (Option α)) :=
 
 Note that if this function is called twice, each `forAsync` only gets half the messages.
 -/
-@[deprecated "Use Std.Channel.forAsync from Std.Sync.Channel instead" (since := "2024-12-02")]
 partial def Channel.forAsync (f : α → BaseIO Unit) (ch : Channel α)
     (prio : Task.Priority := .default) : BaseIO (Task Unit) := do
   BaseIO.bindTask (prio := prio) (← ch.recv?) fun
@@ -105,13 +96,11 @@ Receives all currently queued messages from the channel.
 
 Those messages are dequeued and will not be returned by `recv?`.
 -/
-@[deprecated "Use Std.Channel.recvAllCurrent from Std.Sync.Channel instead" (since := "2024-12-02")]
 def Channel.recvAllCurrent (ch : Channel α) : BaseIO (Array α) :=
   ch.atomically do
     modifyGet fun st => (st.values.toArray, { st with values := ∅ })
 
 /-- Type tag for synchronous (blocking) operations on a `Channel`. -/
-@[deprecated "Use Std.Channel.Sync from Std.Sync.Channel instead" (since := "2024-12-02")]
 def Channel.Sync := Channel
 
 /--
@@ -121,7 +110,6 @@ For example, `ch.sync.recv?` blocks until the next message,
 and `for msg in ch.sync do ...` iterates synchronously over the channel.
 These functions should only be used in dedicated threads.
 -/
-@[deprecated "Use Std.Channel.sync from Std.Sync.Channel instead" (since := "2024-12-02")]
 def Channel.sync (ch : Channel α) : Channel.Sync α := ch
 
 /--
@@ -130,11 +118,9 @@ Synchronously receives a message from the channel.
 Every message is only received once.
 Returns `none` if the channel is closed and the queue is empty.
 -/
-@[deprecated "Use Std.Channel.Sync.recv? from Std.Sync.Channel instead" (since := "2024-12-02")]
 def Channel.Sync.recv? (ch : Channel.Sync α) : BaseIO (Option α) := do
   IO.wait (← Channel.recv? ch)
 
-@[deprecated "Use Std.Channel.Sync.forIn from Std.Sync.Channel instead" (since := "2024-12-02")]
 private partial def Channel.Sync.forIn [Monad m] [MonadLiftT BaseIO m]
     (ch : Channel.Sync α) (f : α → β → m (ForInStep β)) : β → m β := fun b => do
   match ← ch.recv? with

src/Init/Data/Char/Basic.lean

@@ -4,7 +4,7 @@ Released under Apache 2.0 license as described in the file LICENSE.
 Author: Leonardo de Moura
 -/
 prelude
-import Init.Data.UInt.BasicAux
+import Init.Data.UInt.Basic
 
 /-- Determines if the given integer is a valid [Unicode scalar value](https://www.unicode.org/glossary/#unicode_scalar_value).
 
@@ -42,10 +42,8 @@ theorem isValidUInt32 (n : Nat) (h : isValidCharNat n) : n < UInt32.size := by
 
 theorem isValidChar_of_isValidCharNat (n : Nat) (h : isValidCharNat n) : isValidChar (UInt32.ofNat' n (isValidUInt32 n h)) :=
   match h with
-  | Or.inl h =>
-    Or.inl (UInt32.ofNat'_lt_of_lt _ (by decide) h)
-  | Or.inr ⟨h₁, h₂⟩ =>
-    Or.inr ⟨UInt32.lt_ofNat'_of_lt _ (by decide) h₁, UInt32.ofNat'_lt_of_lt _ (by decide) h₂⟩
+  | Or.inl h        => Or.inl h
+  | Or.inr ⟨h₁, h₂⟩ => Or.inr ⟨h₁, h₂⟩
 
 theorem isValidChar_zero : isValidChar 0 :=
   Or.inl (by decide)
@@ -59,7 +57,7 @@ theorem isValidChar_zero : isValidChar 0 :=
   c.val.toUInt8
 
 /-- The numbers from 0 to 256 are all valid UTF-8 characters, so we can embed one in the other. -/
-def ofUInt8 (n : UInt8) : Char := ⟨n.toUInt32, .inl (Nat.lt_trans n.toBitVec.isLt (by decide))⟩
+def ofUInt8 (n : UInt8) : Char := ⟨n.toUInt32, .inl (Nat.lt_trans n.1.2 (by decide))⟩
 
 instance : Inhabited Char where
   default := 'A'

src/Init/Data/Fin/Basic.lean

@@ -36,6 +36,12 @@ def succ : Fin n → Fin (n + 1)
 
 variable {n : Nat}
 
+/--
+Returns `a` modulo `n + 1` as a `Fin n.succ`.
+-/
+protected def ofNat {n : Nat} (a : Nat) : Fin (n + 1) :=
+  ⟨a % (n+1), Nat.mod_lt _ (Nat.zero_lt_succ _)⟩
+
 /--
 Returns `a` modulo `n` as a `Fin n`.
 
@@ -44,12 +50,9 @@ The assumption `NeZero n` ensures that `Fin n` is nonempty.
 protected def ofNat' (n : Nat) [NeZero n] (a : Nat) : Fin n :=
   ⟨a % n, Nat.mod_lt _ (pos_of_neZero n)⟩
 
-/--
-Returns `a` modulo `n + 1` as a `Fin n.succ`.
--/
-@[deprecated Fin.ofNat' (since := "2024-11-27")]
-protected def ofNat {n : Nat} (a : Nat) : Fin (n + 1) :=
-  ⟨a % (n+1), Nat.mod_lt _ (Nat.zero_lt_succ _)⟩
+-- We intend to deprecate `Fin.ofNat` in favor of `Fin.ofNat'` (and later rename).
+-- This is waiting on https://github.com/leanprover/lean4/pull/5323
+-- attribute [deprecated Fin.ofNat' (since := "2024-09-16")] Fin.ofNat
 
 private theorem mlt {b : Nat} : {a : Nat} → a < n → b % n < n
   | 0,   h => Nat.mod_lt _ h
@@ -162,7 +165,6 @@ theorem modn_lt : ∀ {m : Nat} (i : Fin n), m > 0 → (modn i m).val < m
 theorem val_lt_of_le (i : Fin b) (h : b ≤ n) : i.val < n :=
   Nat.lt_of_lt_of_le i.isLt h
 
-/-- If you actually have an element of `Fin n`, then the `n` is always positive -/
 protected theorem pos (i : Fin n) : 0 < n :=
   Nat.lt_of_le_of_lt (Nat.zero_le _) i.2
 
@@ -176,7 +178,7 @@ protected theorem pos (i : Fin n) : 0 < n :=
 @[inline] def castLE (h : n ≤ m) (i : Fin n) : Fin m := ⟨i, Nat.lt_of_lt_of_le i.2 h⟩
 
 /-- `cast eq i` embeds `i` into an equal `Fin` type. -/
-@[inline] protected def cast (eq : n = m) (i : Fin n) : Fin m := ⟨i, eq ▸ i.2⟩
+@[inline] def cast (eq : n = m) (i : Fin n) : Fin m := ⟨i, eq ▸ i.2⟩
 
 /-- `castAdd m i` embeds `i : Fin n` in `Fin (n+m)`. See also `Fin.natAdd` and `Fin.addNat`. -/
 @[inline] def castAdd (m) : Fin n → Fin (n + m) :=

src/Init/Data/Fin/Fold.lean

@@ -5,217 +5,22 @@ Authors: François G. Dorais
 -/
 prelude
 import Init.Data.Nat.Linear
-import Init.Control.Lawful.Basic
-import Init.Data.Fin.Lemmas
 
 namespace Fin
 
 /-- Folds over `Fin n` from the left: `foldl 3 f x = f (f (f x 0) 1) 2`. -/
 @[inline] def foldl (n) (f : α → Fin n → α) (init : α) : α := loop init 0 where
   /-- Inner loop for `Fin.foldl`. `Fin.foldl.loop n f x i = f (f (f x i) ...) (n-1)`  -/
-  @[semireducible, specialize] loop (x : α) (i : Nat) : α :=
+  loop (x : α) (i : Nat) : α :=
     if h : i < n then loop (f x ⟨i, h⟩) (i+1) else x
   termination_by n - i
-
-/-- Folds over `Fin n` from the right: `foldr 3 f x = f 0 (f 1 (f 2 x))`. -/
-@[inline] def foldr (n) (f : Fin n → α → α) (init : α) : α := loop n (Nat.le_refl n) init where
-  /-- Inner loop for `Fin.foldr`. `Fin.foldr.loop n f i x = f 0 (f ... (f (i-1) x))`  -/
-  @[specialize] loop : (i : _) → i ≤ n → α → α
-  | 0, _, x => x
-  | i+1, h, x => loop i (Nat.le_of_lt h) (f ⟨i, h⟩ x)
-  termination_by structural i => i
-
-/--
-Folds a monadic function over `Fin n` from left to right:
-```
-Fin.foldlM n f x₀ = do
-  let x₁ ← f x₀ 0
-  let x₂ ← f x₁ 1
-  ...
-  let xₙ ← f xₙ₋₁ (n-1)
-  pure xₙ
-```
--/
-@[inline] def foldlM [Monad m] (n) (f : α → Fin n → m α) (init : α) : m α := loop init 0 where
-  /--
-  Inner loop for `Fin.foldlM`.
-  ```
-  Fin.foldlM.loop n f xᵢ i = do
-    let xᵢ₊₁ ← f xᵢ i
-    ...
-    let xₙ ← f xₙ₋₁ (n-1)
-    pure xₙ
-  ```
-  -/
-  @[semireducible, specialize] loop (x : α) (i : Nat) : m α := do
-    if h : i < n then f x ⟨i, h⟩ >>= (loop · (i+1)) else pure x
-  termination_by n - i
   decreasing_by decreasing_trivial_pre_omega
 
-/--
-Folds a monadic function over `Fin n` from right to left:
-```
-Fin.foldrM n f xₙ = do
-  let xₙ₋₁ ← f (n-1) xₙ
-  let xₙ₋₂ ← f (n-2) xₙ₋₁
-  ...
-  let x₀ ← f 0 x₁
-  pure x₀
-```
--/
-@[inline] def foldrM [Monad m] (n) (f : Fin n → α → m α) (init : α) : m α :=
-  loop ⟨n, Nat.le_refl n⟩ init where
-  /--
-  Inner loop for `Fin.foldrM`.
-  ```
-  Fin.foldrM.loop n f i xᵢ = do
-    let xᵢ₋₁ ← f (i-1) xᵢ
-    ...
-    let x₁ ← f 1 x₂
-    let x₀ ← f 0 x₁
-    pure x₀
-  ```
-  -/
-  @[semireducible, specialize] loop : {i // i ≤ n} → α → m α
-  | ⟨0, _⟩, x => pure x
-  | ⟨i+1, h⟩, x => f ⟨i, h⟩ x >>= loop ⟨i, Nat.le_of_lt h⟩
-
-/-! ### foldlM -/
-
-theorem foldlM_loop_lt [Monad m] (f : α → Fin n → m α) (x) (h : i < n) :
-    foldlM.loop n f x i = f x ⟨i, h⟩ >>= (foldlM.loop n f . (i+1)) := by
-  rw [foldlM.loop, dif_pos h]
-
-theorem foldlM_loop_eq [Monad m] (f : α → Fin n → m α) (x) : foldlM.loop n f x n = pure x := by
-  rw [foldlM.loop, dif_neg (Nat.lt_irrefl _)]
-
-theorem foldlM_loop [Monad m] (f : α → Fin (n+1) → m α) (x) (h : i < n+1) :
-    foldlM.loop (n+1) f x i = f x ⟨i, h⟩ >>= (foldlM.loop n (fun x j => f x j.succ) . i) := by
-  if h' : i < n then
-    rw [foldlM_loop_lt _ _ h]
-    congr; funext
-    rw [foldlM_loop_lt _ _ h', foldlM_loop]; rfl
-  else
-    cases Nat.le_antisymm (Nat.le_of_lt_succ h) (Nat.not_lt.1 h')
-    rw [foldlM_loop_lt]
-    congr; funext
-    rw [foldlM_loop_eq, foldlM_loop_eq]
-termination_by n - i
-
-@[simp] theorem foldlM_zero [Monad m] (f : α → Fin 0 → m α) (x) : foldlM 0 f x = pure x :=
-  foldlM_loop_eq ..
-
-theorem foldlM_succ [Monad m] (f : α → Fin (n+1) → m α) (x) :
-    foldlM (n+1) f x = f x 0 >>= foldlM n (fun x j => f x j.succ) := foldlM_loop ..
-
-/-! ### foldrM -/
-
-theorem foldrM_loop_zero [Monad m] (f : Fin n → α → m α) (x) :
-    foldrM.loop n f ⟨0, Nat.zero_le _⟩ x = pure x := by
-  rw [foldrM.loop]
-
-theorem foldrM_loop_succ [Monad m] (f : Fin n → α → m α) (x) (h : i < n) :
-    foldrM.loop n f ⟨i+1, h⟩ x = f ⟨i, h⟩ x >>= foldrM.loop n f ⟨i, Nat.le_of_lt h⟩ := by
-  rw [foldrM.loop]
-
-theorem foldrM_loop [Monad m] [LawfulMonad m] (f : Fin (n+1) → α → m α) (x) (h : i+1 ≤ n+1) :
-    foldrM.loop (n+1) f ⟨i+1, h⟩ x =
-      foldrM.loop n (fun j => f j.succ) ⟨i, Nat.le_of_succ_le_succ h⟩ x >>= f 0 := by
-  induction i generalizing x with
-  | zero =>
-    rw [foldrM_loop_zero, foldrM_loop_succ, pure_bind]
-    conv => rhs; rw [←bind_pure (f 0 x)]
-    congr; funext
-  | succ i ih =>
-    rw [foldrM_loop_succ, foldrM_loop_succ, bind_assoc]
-    congr; funext; exact ih ..
-
-@[simp] theorem foldrM_zero [Monad m] (f : Fin 0 → α → m α) (x) : foldrM 0 f x = pure x :=
-  foldrM_loop_zero ..
-
-theorem foldrM_succ [Monad m] [LawfulMonad m] (f : Fin (n+1) → α → m α) (x) :
-    foldrM (n+1) f x = foldrM n (fun i => f i.succ) x >>= f 0 := foldrM_loop ..
-
-/-! ### foldl -/
-
-theorem foldl_loop_lt (f : α → Fin n → α) (x) (h : i < n) :
-    foldl.loop n f x i = foldl.loop n f (f x ⟨i, h⟩) (i+1) := by
-  rw [foldl.loop, dif_pos h]
-
-theorem foldl_loop_eq (f : α → Fin n → α) (x) : foldl.loop n f x n = x := by
-  rw [foldl.loop, dif_neg (Nat.lt_irrefl _)]
-
-theorem foldl_loop (f : α → Fin (n+1) → α) (x) (h : i < n+1) :
-    foldl.loop (n+1) f x i = foldl.loop n (fun x j => f x j.succ) (f x ⟨i, h⟩) i := by
-  if h' : i < n then
-    rw [foldl_loop_lt _ _ h]
-    rw [foldl_loop_lt _ _ h', foldl_loop]; rfl
-  else
-    cases Nat.le_antisymm (Nat.le_of_lt_succ h) (Nat.not_lt.1 h')
-    rw [foldl_loop_lt]
-    rw [foldl_loop_eq, foldl_loop_eq]
-
-@[simp] theorem foldl_zero (f : α → Fin 0 → α) (x) : foldl 0 f x = x :=
-  foldl_loop_eq ..
-
-theorem foldl_succ (f : α → Fin (n+1) → α) (x) :
-    foldl (n+1) f x = foldl n (fun x i => f x i.succ) (f x 0) :=
-  foldl_loop ..
-
-theorem foldl_succ_last (f : α → Fin (n+1) → α) (x) :
-    foldl (n+1) f x = f (foldl n (f · ·.castSucc) x) (last n) := by
-  rw [foldl_succ]
-  induction n generalizing x with
-  | zero => simp [foldl_succ, Fin.last]
-  | succ n ih => rw [foldl_succ, ih (f · ·.succ), foldl_succ]; simp [succ_castSucc]
-
-theorem foldl_eq_foldlM (f : α → Fin n → α) (x) :
-    foldl n f x = foldlM (m:=Id) n f x := by
-  induction n generalizing x <;> simp [foldl_succ, foldlM_succ, *]
-
-/-! ### foldr -/
-
-theorem foldr_loop_zero (f : Fin n → α → α) (x) :
-    foldr.loop n f 0 (Nat.zero_le _) x = x := by
-  rw [foldr.loop]
-
-theorem foldr_loop_succ (f : Fin n → α → α) (x) (h : i < n) :
-    foldr.loop n f (i+1) h x = foldr.loop n f i (Nat.le_of_lt h) (f ⟨i, h⟩ x) := by
-  rw [foldr.loop]
-
-theorem foldr_loop (f : Fin (n+1) → α → α) (x) (h : i+1 ≤ n+1) :
-    foldr.loop (n+1) f (i+1) h x =
-      f 0 (foldr.loop n (fun j => f j.succ) i (Nat.le_of_succ_le_succ h) x) := by
-  induction i generalizing x with
-  | zero => simp [foldr_loop_succ, foldr_loop_zero]
-  | succ i ih => rw [foldr_loop_succ, ih]; rfl
-
-@[simp] theorem foldr_zero (f : Fin 0 → α → α) (x) : foldr 0 f x = x :=
-  foldr_loop_zero ..
-
-theorem foldr_succ (f : Fin (n+1) → α → α) (x) :
-    foldr (n+1) f x = f 0 (foldr n (fun i => f i.succ) x) := foldr_loop ..
-
-theorem foldr_succ_last (f : Fin (n+1) → α → α) (x) :
-    foldr (n+1) f x = foldr n (f ·.castSucc) (f (last n) x) := by
-  induction n generalizing x with
-  | zero => simp [foldr_succ, Fin.last]
-  | succ n ih => rw [foldr_succ, ih (f ·.succ), foldr_succ]; simp [succ_castSucc]
-
-theorem foldr_eq_foldrM (f : Fin n → α → α) (x) :
-    foldr n f x = foldrM (m:=Id) n f x := by
-  induction n <;> simp [foldr_succ, foldrM_succ, *]
-
-theorem foldl_rev (f : Fin n → α → α) (x) :
-    foldl n (fun x i => f i.rev x) x = foldr n f x := by
-  induction n generalizing x with
-  | zero => simp
-  | succ n ih => rw [foldl_succ, foldr_succ_last, ← ih]; simp [rev_succ]
-
-theorem foldr_rev (f : α → Fin n → α) (x) :
-     foldr n (fun i x => f x i.rev) x = foldl n f x := by
-  induction n generalizing x with
-  | zero => simp
-  | succ n ih => rw [foldl_succ_last, foldr_succ, ← ih]; simp [rev_succ]
+/-- Folds over `Fin n` from the right: `foldr 3 f x = f 0 (f 1 (f 2 x))`. -/
+@[inline] def foldr (n) (f : Fin n → α → α) (init : α) : α := loop ⟨n, Nat.le_refl n⟩ init where
+  /-- Inner loop for `Fin.foldr`. `Fin.foldr.loop n f i x = f 0 (f ... (f (i-1) x))`  -/
+  loop : {i // i ≤ n} → α → α
+  | ⟨0, _⟩, x => x
+  | ⟨i+1, h⟩, x => loop ⟨i, Nat.le_of_lt h⟩ (f ⟨i, h⟩ x)
 
 end Fin

src/Init/Data/Fin/Lemmas.lean

@@ -13,19 +13,17 @@ import Init.Omega
 
 namespace Fin
 
-@[deprecated Fin.pos (since := "2024-11-11")]
-theorem size_pos (i : Fin n) : 0 < n := i.pos
+/-- If you actually have an element of `Fin n`, then the `n` is always positive -/
+theorem size_pos (i : Fin n) : 0 < n := Nat.lt_of_le_of_lt (Nat.zero_le _) i.2
 
 theorem mod_def (a m : Fin n) : a % m = Fin.mk (a % m) (Nat.lt_of_le_of_lt (Nat.mod_le _ _) a.2) :=
   rfl
 
-theorem mul_def (a b : Fin n) : a * b = Fin.mk ((a * b) % n) (Nat.mod_lt _ a.pos) := rfl
+theorem mul_def (a b : Fin n) : a * b = Fin.mk ((a * b) % n) (Nat.mod_lt _ a.size_pos) := rfl
 
-theorem sub_def (a b : Fin n) : a - b = Fin.mk (((n - b) + a) % n) (Nat.mod_lt _ a.pos) := rfl
+theorem sub_def (a b : Fin n) : a - b = Fin.mk (((n - b) + a) % n) (Nat.mod_lt _ a.size_pos) := rfl
 
-theorem pos' : ∀ [Nonempty (Fin n)], 0 < n | ⟨i⟩ => i.pos
-
-@[deprecated pos' (since := "2024-11-11")] abbrev size_pos' := @pos'
+theorem size_pos' : ∀ [Nonempty (Fin n)], 0 < n | ⟨i⟩ => i.size_pos
 
 @[simp] theorem is_lt (a : Fin n) : (a : Nat) < n := a.2
 
@@ -242,17 +240,13 @@ theorem fin_one_eq_zero (a : Fin 1) : a = 0 := Subsingleton.elim a 0
   rw [eq_comm]
   simp
 
-theorem add_def (a b : Fin n) : a + b = Fin.mk ((a + b) % n) (Nat.mod_lt _ a.pos) := rfl
+theorem add_def (a b : Fin n) : a + b = Fin.mk ((a + b) % n) (Nat.mod_lt _ a.size_pos) := rfl
 
 theorem val_add (a b : Fin n) : (a + b).val = (a.val + b.val) % n := rfl
 
-@[simp] protected theorem zero_add [NeZero n] (k : Fin n) : (0 : Fin n) + k = k := by
+@[simp] protected theorem zero_add {n : Nat} [NeZero n] (i : Fin n) : (0 : Fin n) + i = i := by
   ext
-  simp [Fin.add_def, Nat.mod_eq_of_lt k.2]
-
-@[simp] protected theorem add_zero [NeZero n] (k : Fin n) : k + 0 = k := by
-  ext
-  simp [add_def, Nat.mod_eq_of_lt k.2]
+  simp [Fin.add_def, Nat.mod_eq_of_lt i.2]
 
 theorem val_add_one_of_lt {n : Nat} {i : Fin n.succ} (h : i < last _) : (i + 1).1 = i + 1 := by
   match n with
@@ -370,25 +364,25 @@ theorem succ_succ_ne_one (a : Fin n) : Fin.succ (Fin.succ a) ≠ 1 :=
     Fin.castLE mn ∘ Fin.castLE km = Fin.castLE (Nat.le_trans km mn) :=
   funext (castLE_castLE km mn)
 
-@[simp] theorem coe_cast (h : n = m) (i : Fin n) : (i.cast h : Nat) = i := rfl
+@[simp] theorem coe_cast (h : n = m) (i : Fin n) : (cast h i : Nat) = i := rfl
 
-@[simp] theorem cast_last {n' : Nat} {h : n + 1 = n' + 1} : (last n).cast h  = last n' :=
+@[simp] theorem cast_last {n' : Nat} {h : n + 1 = n' + 1} : cast h (last n) = last n' :=
   Fin.ext (by rw [coe_cast, val_last, val_last, Nat.succ.inj h])
 
-@[simp] theorem cast_mk (h : n = m) (i : Nat) (hn : i < n) : Fin.cast h ⟨i, hn⟩ = ⟨i, h ▸ hn⟩ := rfl
+@[simp] theorem cast_mk (h : n = m) (i : Nat) (hn : i < n) : cast h ⟨i, hn⟩ = ⟨i, h ▸ hn⟩ := rfl
 
-@[simp] theorem cast_refl (n : Nat) (h : n = n) : Fin.cast h = id := by
+@[simp] theorem cast_refl (n : Nat) (h : n = n) : cast h = id := by
   ext
   simp
 
 @[simp] theorem cast_trans {k : Nat} (h : n = m) (h' : m = k) {i : Fin n} :
-    (i.cast h).cast h' = i.cast (Eq.trans h h') := rfl
+    cast h' (cast h i) = cast (Eq.trans h h') i := rfl
 
 theorem castLE_of_eq {m n : Nat} (h : m = n) {h' : m ≤ n} : castLE h' = Fin.cast h := rfl
 
 @[simp] theorem coe_castAdd (m : Nat) (i : Fin n) : (castAdd m i : Nat) = i := rfl
 
-@[simp] theorem castAdd_zero : (castAdd 0 : Fin n → Fin (n + 0)) = Fin.cast rfl := rfl
+@[simp] theorem castAdd_zero : (castAdd 0 : Fin n → Fin (n + 0)) = cast rfl := rfl
 
 theorem castAdd_lt {m : Nat} (n : Nat) (i : Fin m) : (castAdd n i : Nat) < m := by simp
 
@@ -406,37 +400,37 @@ theorem castAdd_cast {n n' : Nat} (m : Nat) (i : Fin n') (h : n' = n) :
     castAdd m (Fin.cast h i) = Fin.cast (congrArg (. + m) h) (castAdd m i) := Fin.ext rfl
 
 theorem cast_castAdd_left {n n' m : Nat} (i : Fin n') (h : n' + m = n + m) :
-    (i.castAdd m).cast h = (i.cast (Nat.add_right_cancel h)).castAdd m := rfl
+    cast h (castAdd m i) = castAdd m (cast (Nat.add_right_cancel h) i) := rfl
 
 @[simp] theorem cast_castAdd_right {n m m' : Nat} (i : Fin n) (h : n + m' = n + m) :
-    (i.castAdd m').cast h = i.castAdd m := rfl
+    cast h (castAdd m' i) = castAdd m i := rfl
 
 theorem castAdd_castAdd {m n p : Nat} (i : Fin m) :
-    (i.castAdd n).castAdd p = (i.castAdd (n + p)).cast (Nat.add_assoc ..).symm  := rfl
+    castAdd p (castAdd n i) = cast (Nat.add_assoc ..).symm (castAdd (n + p) i) := rfl
 
 /-- The cast of the successor is the successor of the cast. See `Fin.succ_cast_eq` for rewriting in
 the reverse direction. -/
 @[simp] theorem cast_succ_eq {n' : Nat} (i : Fin n) (h : n.succ = n'.succ) :
-    i.succ.cast h = (i.cast (Nat.succ.inj h)).succ := rfl
+    cast h i.succ = (cast (Nat.succ.inj h) i).succ := rfl
 
 theorem succ_cast_eq {n' : Nat} (i : Fin n) (h : n = n') :
-    (i.cast h).succ = i.succ.cast (by rw [h]) := rfl
+    (cast h i).succ = cast (by rw [h]) i.succ := rfl
 
-@[simp] theorem coe_castSucc (i : Fin n) : (i.castSucc : Nat) = i := rfl
+@[simp] theorem coe_castSucc (i : Fin n) : (Fin.castSucc i : Nat) = i := rfl
 
 @[simp] theorem castSucc_mk (n i : Nat) (h : i < n) : castSucc ⟨i, h⟩ = ⟨i, Nat.lt.step h⟩ := rfl
 
 @[simp] theorem cast_castSucc {n' : Nat} {h : n + 1 = n' + 1} {i : Fin n} :
-    i.castSucc.cast h = (i.cast (Nat.succ.inj h)).castSucc := rfl
+    cast h (castSucc i) = castSucc (cast (Nat.succ.inj h) i) := rfl
 
-theorem castSucc_lt_succ (i : Fin n) : i.castSucc < i.succ :=
+theorem castSucc_lt_succ (i : Fin n) : Fin.castSucc i < i.succ :=
   lt_def.2 <| by simp only [coe_castSucc, val_succ, Nat.lt_succ_self]
 
-theorem le_castSucc_iff {i : Fin (n + 1)} {j : Fin n} : i ≤ j.castSucc ↔ i < j.succ := by
+theorem le_castSucc_iff {i : Fin (n + 1)} {j : Fin n} : i ≤ Fin.castSucc j ↔ i < j.succ := by
   simpa only [lt_def, le_def] using Nat.add_one_le_add_one_iff.symm
 
 theorem castSucc_lt_iff_succ_le {n : Nat} {i : Fin n} {j : Fin (n + 1)} :
-    i.castSucc < j ↔ i.succ ≤ j := .rfl
+    Fin.castSucc i < j ↔ i.succ ≤ j := .rfl
 
 @[simp] theorem succ_last (n : Nat) : (last n).succ = last n.succ := rfl
 
@@ -444,48 +438,48 @@ theorem castSucc_lt_iff_succ_le {n : Nat} {i : Fin n} {j : Fin (n + 1)} :
     i.succ = last (n + 1) ↔ i = last n := by rw [← succ_last, succ_inj]
 
 @[simp] theorem castSucc_castLT (i : Fin (n + 1)) (h : (i : Nat) < n) :
-    (castLT i h).castSucc = i := rfl
+    castSucc (castLT i h) = i := rfl
 
 @[simp] theorem castLT_castSucc {n : Nat} (a : Fin n) (h : (a : Nat) < n) :
-    castLT a.castSucc h = a := rfl
+    castLT (castSucc a) h = a := rfl
 
 @[simp] theorem castSucc_lt_castSucc_iff {a b : Fin n} :
-    a.castSucc < b.castSucc ↔ a < b := .rfl
+    Fin.castSucc a < Fin.castSucc b ↔ a < b := .rfl
 
-theorem castSucc_inj {a b : Fin n} : a.castSucc = b.castSucc ↔ a = b := by simp [Fin.ext_iff]
+theorem castSucc_inj {a b : Fin n} : castSucc a = castSucc b ↔ a = b := by simp [Fin.ext_iff]
 
-theorem castSucc_lt_last (a : Fin n) : a.castSucc < last n := a.is_lt
+theorem castSucc_lt_last (a : Fin n) : castSucc a < last n := a.is_lt
 
 @[simp] theorem castSucc_zero : castSucc (0 : Fin (n + 1)) = 0 := rfl
 
 @[simp] theorem castSucc_one {n : Nat} : castSucc (1 : Fin (n + 2)) = 1 := rfl
 
 /-- `castSucc i` is positive when `i` is positive -/
-theorem castSucc_pos {i : Fin (n + 1)} (h : 0 < i) : 0 < i.castSucc := by
+theorem castSucc_pos {i : Fin (n + 1)} (h : 0 < i) : 0 < castSucc i := by
   simpa [lt_def] using h
 
-@[simp] theorem castSucc_eq_zero_iff {a : Fin (n + 1)} : a.castSucc = 0 ↔ a = 0 := by simp [Fin.ext_iff]
+@[simp] theorem castSucc_eq_zero_iff {a : Fin (n + 1)} : castSucc a = 0 ↔ a = 0 := by simp [Fin.ext_iff]
 
-theorem castSucc_ne_zero_iff {a : Fin (n + 1)} : a.castSucc ≠ 0 ↔ a ≠ 0 :=
+theorem castSucc_ne_zero_iff {a : Fin (n + 1)} : castSucc a ≠ 0 ↔ a ≠ 0 :=
   not_congr <| castSucc_eq_zero_iff
 
 theorem castSucc_fin_succ (n : Nat) (j : Fin n) :
-    j.succ.castSucc = (j.castSucc).succ := by simp [Fin.ext_iff]
+    castSucc (Fin.succ j) = Fin.succ (castSucc j) := by simp [Fin.ext_iff]
 
 @[simp]
-theorem coeSucc_eq_succ {a : Fin n} : a.castSucc + 1 = a.succ := by
+theorem coeSucc_eq_succ {a : Fin n} : castSucc a + 1 = a.succ := by
   cases n
   · exact a.elim0
   · simp [Fin.ext_iff, add_def, Nat.mod_eq_of_lt (Nat.succ_lt_succ a.is_lt)]
 
-theorem lt_succ {a : Fin n} : a.castSucc < a.succ := by
+theorem lt_succ {a : Fin n} : castSucc a < a.succ := by
   rw [castSucc, lt_def, coe_castAdd, val_succ]; exact Nat.lt_succ_self a.val
 
 theorem exists_castSucc_eq {n : Nat} {i : Fin (n + 1)} : (∃ j, castSucc j = i) ↔ i ≠ last n :=
   ⟨fun ⟨j, hj⟩ => hj ▸ Fin.ne_of_lt j.castSucc_lt_last,
    fun hi => ⟨i.castLT <| Fin.val_lt_last hi, rfl⟩⟩
 
-theorem succ_castSucc {n : Nat} (i : Fin n) : i.castSucc.succ = i.succ.castSucc := rfl
+theorem succ_castSucc {n : Nat} (i : Fin n) : i.castSucc.succ = castSucc i.succ := rfl
 
 @[simp] theorem coe_addNat (m : Nat) (i : Fin n) : (addNat i m : Nat) = i + m := rfl
 
@@ -502,17 +496,17 @@ theorem le_coe_addNat (m : Nat) (i : Fin n) : m ≤ addNat i m :=
     addNat ⟨i, hi⟩ n = ⟨i + n, Nat.add_lt_add_right hi n⟩ := rfl
 
 @[simp] theorem cast_addNat_zero {n n' : Nat} (i : Fin n) (h : n + 0 = n') :
-    (addNat i 0).cast h = i.cast ((Nat.add_zero _).symm.trans h) := rfl
+    cast h (addNat i 0) = cast ((Nat.add_zero _).symm.trans h) i := rfl
 
 /-- For rewriting in the reverse direction, see `Fin.cast_addNat_left`. -/
 theorem addNat_cast {n n' m : Nat} (i : Fin n') (h : n' = n) :
-    addNat (i.cast h) m = (addNat i m).cast (congrArg (. + m) h) := rfl
+    addNat (cast h i) m = cast (congrArg (. + m) h) (addNat i m) := rfl
 
 theorem cast_addNat_left {n n' m : Nat} (i : Fin n') (h : n' + m = n + m) :
-    (addNat i m).cast h = addNat (i.cast (Nat.add_right_cancel h)) m := rfl
+    cast h (addNat i m) = addNat (cast (Nat.add_right_cancel h) i) m := rfl
 
 @[simp] theorem cast_addNat_right {n m m' : Nat} (i : Fin n) (h : n + m' = n + m) :
-    (addNat i m').cast h = addNat i m :=
+    cast h (addNat i m') = addNat i m :=
   Fin.ext <| (congrArg ((· + ·) (i : Nat)) (Nat.add_left_cancel h) : _)
 
 @[simp] theorem coe_natAdd (n : Nat) {m : Nat} (i : Fin m) : (natAdd n i : Nat) = n + i := rfl
@@ -522,46 +516,46 @@ theorem cast_addNat_left {n n' m : Nat} (i : Fin n') (h : n' + m = n + m) :
 
 theorem le_coe_natAdd (m : Nat) (i : Fin n) : m ≤ natAdd m i := Nat.le_add_right ..
 
-@[simp] theorem natAdd_zero {n : Nat} : natAdd 0 = Fin.cast (Nat.zero_add n).symm := by ext; simp
+@[simp] theorem natAdd_zero {n : Nat} : natAdd 0 = cast (Nat.zero_add n).symm := by ext; simp
 
 /-- For rewriting in the reverse direction, see `Fin.cast_natAdd_right`. -/
 theorem natAdd_cast {n n' : Nat} (m : Nat) (i : Fin n') (h : n' = n) :
-    natAdd m (i.cast h) = (natAdd m i).cast (congrArg _ h) := rfl
+    natAdd m (cast h i) = cast (congrArg _ h) (natAdd m i) := rfl
 
 theorem cast_natAdd_right {n n' m : Nat} (i : Fin n') (h : m + n' = m + n) :
-    (natAdd m i).cast h  = natAdd m (i.cast (Nat.add_left_cancel h)) := rfl
+    cast h (natAdd m i) = natAdd m (cast (Nat.add_left_cancel h) i) := rfl
 
 @[simp] theorem cast_natAdd_left {n m m' : Nat} (i : Fin n) (h : m' + n = m + n) :
-    (natAdd m' i).cast h = natAdd m i :=
+    cast h (natAdd m' i) = natAdd m i :=
   Fin.ext <| (congrArg (· + (i : Nat)) (Nat.add_right_cancel h) : _)
 
 theorem castAdd_natAdd (p m : Nat) {n : Nat} (i : Fin n) :
-    castAdd p (natAdd m i) = (natAdd m (castAdd p i)).cast (Nat.add_assoc ..).symm := rfl
+    castAdd p (natAdd m i) = cast (Nat.add_assoc ..).symm (natAdd m (castAdd p i)) := rfl
 
 theorem natAdd_castAdd (p m : Nat) {n : Nat} (i : Fin n) :
-    natAdd m (castAdd p i) = (castAdd p (natAdd m i)).cast (Nat.add_assoc ..) := rfl
+    natAdd m (castAdd p i) = cast (Nat.add_assoc ..) (castAdd p (natAdd m i)) := rfl
 
 theorem natAdd_natAdd (m n : Nat) {p : Nat} (i : Fin p) :
-    natAdd m (natAdd n i) = (natAdd (m + n) i).cast (Nat.add_assoc ..) :=
+    natAdd m (natAdd n i) = cast (Nat.add_assoc ..) (natAdd (m + n) i) :=
   Fin.ext <| (Nat.add_assoc ..).symm
 
 @[simp]
 theorem cast_natAdd_zero {n n' : Nat} (i : Fin n) (h : 0 + n = n') :
-    (natAdd 0 i).cast h = i.cast ((Nat.zero_add _).symm.trans h) :=
+    cast h (natAdd 0 i) = cast ((Nat.zero_add _).symm.trans h) i :=
   Fin.ext <| Nat.zero_add _
 
 @[simp]
 theorem cast_natAdd (n : Nat) {m : Nat} (i : Fin m) :
-    (natAdd n i).cast (Nat.add_comm ..) = addNat i n := Fin.ext <| Nat.add_comm ..
+    cast (Nat.add_comm ..) (natAdd n i) = addNat i n := Fin.ext <| Nat.add_comm ..
 
 @[simp]
 theorem cast_addNat {n : Nat} (m : Nat) (i : Fin n) :
-    (addNat i m).cast (Nat.add_comm ..) = natAdd m i := Fin.ext <| Nat.add_comm ..
+    cast (Nat.add_comm ..) (addNat i m) = natAdd m i := Fin.ext <| Nat.add_comm ..
 
 @[simp] theorem natAdd_last {m n : Nat} : natAdd n (last m) = last (n + m) := rfl
 
 @[simp] theorem addNat_last (n : Nat) :
-    addNat (last n) m = (last (n + m)).cast (by omega) := by
+    addNat (last n) m = cast (by omega) (last (n + m)) := by
   ext
   simp
 
@@ -588,8 +582,8 @@ theorem rev_succ (k : Fin n) : rev (succ k) = castSucc (rev k) := k.rev_addNat 1
 @[simp] theorem coe_pred (j : Fin (n + 1)) (h : j ≠ 0) : (j.pred h : Nat) = j - 1 := rfl
 
 @[simp] theorem succ_pred : ∀ (i : Fin (n + 1)) (h : i ≠ 0), (i.pred h).succ = i
-  | ⟨0, _⟩, hi => by simp only [mk_zero, ne_eq, not_true] at hi
-  | ⟨_ + 1, _⟩, _ => rfl
+  | ⟨0, h⟩, hi => by simp only [mk_zero, ne_eq, not_true] at hi
+  | ⟨n + 1, h⟩, hi => rfl
 
 @[simp]
 theorem pred_succ (i : Fin n) {h : i.succ ≠ 0} : i.succ.pred h = i := by
@@ -642,7 +636,7 @@ theorem pred_add_one (i : Fin (n + 2)) (h : (i : Nat) < n + 1) :
   ext
   simp
 
-@[simp] theorem subNat_one_succ (i : Fin (n + 1)) (h : 1 ≤ (i : Nat)) : (subNat 1 i h).succ = i := by
+@[simp] theorem subNat_one_succ (i : Fin (n + 1)) (h : 1 ≤ ↑i) : (subNat 1 i h).succ = i := by
   ext
   simp
   omega
@@ -657,7 +651,7 @@ theorem pred_add_one (i : Fin (n + 2)) (h : (i : Nat) < n + 1) :
     subNat m (addNat i m) h = i := Fin.ext <| Nat.add_sub_cancel i m
 
 @[simp] theorem natAdd_subNat_cast {i : Fin (n + m)} (h : n ≤ i) :
-    natAdd n (subNat n (i.cast (Nat.add_comm ..)) h) = i := by simp [← cast_addNat]
+    natAdd n (subNat n (cast (Nat.add_comm ..) i) h) = i := by simp [← cast_addNat]
 
 /-! ### recursion and induction principles -/
 

src/Init/Data/Float.lean

@@ -31,7 +31,7 @@ opaque floatSpec : FloatSpec := {
 structure Float where
   val : floatSpec.float
 
-instance : Nonempty Float := ⟨{ val := floatSpec.val }⟩
+instance : Inhabited Float := ⟨{ val := floatSpec.val }⟩
 
 @[extern "lean_float_add"] opaque Float.add : Float → Float → Float
 @[extern "lean_float_sub"] opaque Float.sub : Float → Float → Float
@@ -47,25 +47,6 @@ def Float.lt : Float → Float → Prop := fun a b =>
 def Float.le : Float → Float → Prop := fun a b =>
   floatSpec.le a.val b.val
 
-/--
-Raw transmutation from `UInt64`.
-
-Floats and UInts have the same endianness on all supported platforms.
-IEEE 754 very precisely specifies the bit layout of floats.
--/
-@[extern "lean_float_of_bits"] opaque Float.ofBits : UInt64 → Float
-
-/--
-Raw transmutation to `UInt64`.
-
-Floats and UInts have the same endianness on all supported platforms.
-IEEE 754 very precisely specifies the bit layout of floats.
-
-Note that this function is distinct from `Float.toUInt64`, which attempts
-to preserve the numeric value, and not the bitwise value.
--/
-@[extern "lean_float_to_bits"] opaque Float.toBits : Float → UInt64
-
 instance : Add Float := ⟨Float.add⟩
 instance : Sub Float := ⟨Float.sub⟩
 instance : Mul Float := ⟨Float.mul⟩
@@ -91,35 +72,21 @@ instance floatDecLt (a b : Float) : Decidable (a < b) := Float.decLt a b
 instance floatDecLe (a b : Float) : Decidable (a ≤ b) := Float.decLe a b
 
 @[extern "lean_float_to_string"] opaque Float.toString : Float → String
-/-- If the given float is non-negative, truncates the value to the nearest non-negative integer.
-If negative or NaN, returns `0`.
-If larger than the maximum value for `UInt8` (including Inf), returns the maximum value of `UInt8`
-(i.e. `UInt8.size - 1`).
--/
+
+/-- If the given float is positive, truncates the value to the nearest positive integer.
+If negative or larger than the maximum value for UInt8, returns 0. -/
 @[extern "lean_float_to_uint8"] opaque Float.toUInt8 : Float → UInt8
-/-- If the given float is non-negative, truncates the value to the nearest non-negative integer.
-If negative or NaN, returns `0`.
-If larger than the maximum value for `UInt16` (including Inf), returns the maximum value of `UInt16`
-(i.e. `UInt16.size - 1`).
--/
+/-- If the given float is positive, truncates the value to the nearest positive integer.
+If negative or larger than the maximum value for UInt16, returns 0. -/
 @[extern "lean_float_to_uint16"] opaque Float.toUInt16 : Float → UInt16
-/-- If the given float is non-negative, truncates the value to the nearest non-negative integer.
-If negative or NaN, returns `0`.
-If larger than the maximum value for `UInt32` (including Inf), returns the maximum value of `UInt32`
-(i.e. `UInt32.size - 1`).
--/
+/-- If the given float is positive, truncates the value to the nearest positive integer.
+If negative or larger than the maximum value for UInt32, returns 0. -/
 @[extern "lean_float_to_uint32"] opaque Float.toUInt32 : Float → UInt32
-/-- If the given float is non-negative, truncates the value to the nearest non-negative integer.
-If negative or NaN, returns `0`.
-If larger than the maximum value for `UInt64` (including Inf), returns the maximum value of `UInt64`
-(i.e. `UInt64.size - 1`).
--/
+/-- If the given float is positive, truncates the value to the nearest positive integer.
+If negative or larger than the maximum value for UInt64, returns 0. -/
 @[extern "lean_float_to_uint64"] opaque Float.toUInt64 : Float → UInt64
-/-- If the given float is non-negative, truncates the value to the nearest non-negative integer.
-If negative or NaN, returns `0`.
-If larger than the maximum value for `USize` (including Inf), returns the maximum value of `USize`
-(i.e. `USize.size - 1`). This value is platform dependent).
--/
+/-- If the given float is positive, truncates the value to the nearest positive integer.
+If negative or larger than the maximum value for USize, returns 0. -/
 @[extern "lean_float_to_usize"] opaque Float.toUSize : Float → USize
 
 @[extern "lean_float_isnan"] opaque Float.isNaN : Float → Bool
@@ -136,9 +103,6 @@ instance : ToString Float where
 
 @[extern "lean_uint64_to_float"] opaque UInt64.toFloat (n : UInt64) : Float
 
-instance : Inhabited Float where
-  default := UInt64.toFloat 0
-
 instance : Repr Float where
   reprPrec n prec := if n < UInt64.toFloat 0 then Repr.addAppParen (toString n) prec else toString n
 

src/Init/Data/Float32.lean

@@ -1,180 +0,0 @@
-/-
-Copyright (c) 2023 Amazon.com, Inc. or its affiliates. All Rights Reserved.
-Released under Apache 2.0 license as described in the file LICENSE.
-Authors: Leonardo de Moura
--/
-prelude
-import Init.Core
-import Init.Data.Int.Basic
-import Init.Data.ToString.Basic
-import Init.Data.Float
-
-/-
-#exit -- TODO: Remove after update stage0
-
--- Just show FloatSpec is inhabited.
-opaque float32Spec : FloatSpec := {
-  float := Unit,
-  val   := (),
-  lt    := fun _ _ => True,
-  le    := fun _ _ => True,
-  decLt := fun _ _ => inferInstanceAs (Decidable True),
-  decLe := fun _ _ => inferInstanceAs (Decidable True)
-}
-
-/-- Native floating point type, corresponding to the IEEE 754 *binary32* format
-(`float` in C or `f32` in Rust). -/
-structure Float32 where
-  val : float32Spec.float
-
-instance : Nonempty Float32 := ⟨{ val := float32Spec.val }⟩
-
-@[extern "lean_float32_add"] opaque Float32.add : Float32 → Float32 → Float32
-@[extern "lean_float32_sub"] opaque Float32.sub : Float32 → Float32 → Float32
-@[extern "lean_float32_mul"] opaque Float32.mul : Float32 → Float32 → Float32
-@[extern "lean_float32_div"] opaque Float32.div : Float32 → Float32 → Float32
-@[extern "lean_float32_negate"] opaque Float32.neg : Float32 → Float32
-
-set_option bootstrap.genMatcherCode false
-def Float32.lt : Float32 → Float32 → Prop := fun a b =>
-  match a, b with
-  | ⟨a⟩, ⟨b⟩ => float32Spec.lt a b
-
-def Float32.le : Float32 → Float32 → Prop := fun a b =>
-  float32Spec.le a.val b.val
-
-/--
-Raw transmutation from `UInt32`.
-
-Float32s and UInts have the same endianness on all supported platforms.
-IEEE 754 very precisely specifies the bit layout of floats.
--/
-@[extern "lean_float32_of_bits"] opaque Float32.ofBits : UInt32 → Float32
-
-/--
-Raw transmutation to `UInt32`.
-
-Float32s and UInts have the same endianness on all supported platforms.
-IEEE 754 very precisely specifies the bit layout of floats.
-
-Note that this function is distinct from `Float32.toUInt32`, which attempts
-to preserve the numeric value, and not the bitwise value.
--/
-@[extern "lean_float32_to_bits"] opaque Float32.toBits : Float32 → UInt32
-
-instance : Add Float32 := ⟨Float32.add⟩
-instance : Sub Float32 := ⟨Float32.sub⟩
-instance : Mul Float32 := ⟨Float32.mul⟩
-instance : Div Float32 := ⟨Float32.div⟩
-instance : Neg Float32 := ⟨Float32.neg⟩
-instance : LT Float32  := ⟨Float32.lt⟩
-instance : LE Float32  := ⟨Float32.le⟩
-
-/-- Note: this is not reflexive since `NaN != NaN`.-/
-@[extern "lean_float32_beq"] opaque Float32.beq (a b : Float32) : Bool
-
-instance : BEq Float32 := ⟨Float32.beq⟩
-
-@[extern "lean_float32_decLt"] opaque Float32.decLt (a b : Float32) : Decidable (a < b) :=
-  match a, b with
-  | ⟨a⟩, ⟨b⟩ => float32Spec.decLt a b
-
-@[extern "lean_float32_decLe"] opaque Float32.decLe (a b : Float32) : Decidable (a ≤ b) :=
-  match a, b with
-  | ⟨a⟩, ⟨b⟩ => float32Spec.decLe a b
-
-instance float32DecLt (a b : Float32) : Decidable (a < b) := Float32.decLt a b
-instance float32DecLe (a b : Float32) : Decidable (a ≤ b) := Float32.decLe a b
-
-@[extern "lean_float32_to_string"] opaque Float32.toString : Float32 → String
-/-- If the given float is non-negative, truncates the value to the nearest non-negative integer.
-If negative or NaN, returns `0`.
-If larger than the maximum value for `UInt8` (including Inf), returns the maximum value of `UInt8`
-(i.e. `UInt8.size - 1`).
--/
-@[extern "lean_float32_to_uint8"] opaque Float32.toUInt8 : Float32 → UInt8
-/-- If the given float is non-negative, truncates the value to the nearest non-negative integer.
-If negative or NaN, returns `0`.
-If larger than the maximum value for `UInt16` (including Inf), returns the maximum value of `UInt16`
-(i.e. `UInt16.size - 1`).
--/
-@[extern "lean_float32_to_uint16"] opaque Float32.toUInt16 : Float32 → UInt16
-/-- If the given float is non-negative, truncates the value to the nearest non-negative integer.
-If negative or NaN, returns `0`.
-If larger than the maximum value for `UInt32` (including Inf), returns the maximum value of `UInt32`
-(i.e. `UInt32.size - 1`).
--/
-@[extern "lean_float32_to_uint32"] opaque Float32.toUInt32 : Float32 → UInt32
-/-- If the given float is non-negative, truncates the value to the nearest non-negative integer.
-If negative or NaN, returns `0`.
-If larger than the maximum value for `UInt64` (including Inf), returns the maximum value of `UInt64`
-(i.e. `UInt64.size - 1`).
--/
-@[extern "lean_float32_to_uint64"] opaque Float32.toUInt64 : Float32 → UInt64
-/-- If the given float is non-negative, truncates the value to the nearest non-negative integer.
-If negative or NaN, returns `0`.
-If larger than the maximum value for `USize` (including Inf), returns the maximum value of `USize`
-(i.e. `USize.size - 1`). This value is platform dependent).
--/
-@[extern "lean_float32_to_usize"] opaque Float32.toUSize : Float32 → USize
-
-@[extern "lean_float32_isnan"] opaque Float32.isNaN : Float32 → Bool
-@[extern "lean_float32_isfinite"] opaque Float32.isFinite : Float32 → Bool
-@[extern "lean_float32_isinf"] opaque Float32.isInf : Float32 → Bool
-/-- Splits the given float `x` into a significand/exponent pair `(s, i)`
-such that `x = s * 2^i` where `s ∈ (-1;-0.5] ∪ [0.5; 1)`.
-Returns an undefined value if `x` is not finite.
--/
-@[extern "lean_float32_frexp"] opaque Float32.frExp : Float32 → Float32 × Int
-
-instance : ToString Float32 where
-  toString := Float32.toString
-
-@[extern "lean_uint64_to_float"] opaque UInt64.toFloat32 (n : UInt64) : Float32
-
-instance : Inhabited Float32 where
-  default := UInt64.toFloat32 0
-
-instance : Repr Float32 where
-  reprPrec n prec := if n < UInt64.toFloat32 0 then Repr.addAppParen (toString n) prec else toString n
-
-instance : ReprAtom Float32  := ⟨⟩
-
-@[extern "sinf"] opaque Float32.sin : Float32 → Float32
-@[extern "cosf"] opaque Float32.cos : Float32 → Float32
-@[extern "tanf"] opaque Float32.tan : Float32 → Float32
-@[extern "asinf"] opaque Float32.asin : Float32 → Float32
-@[extern "acosf"] opaque Float32.acos : Float32 → Float32
-@[extern "atanf"] opaque Float32.atan : Float32 → Float32
-@[extern "atan2f"] opaque Float32.atan2 : Float32 → Float32 → Float32
-@[extern "sinhf"] opaque Float32.sinh : Float32 → Float32
-@[extern "coshf"] opaque Float32.cosh : Float32 → Float32
-@[extern "tanhf"] opaque Float32.tanh : Float32 → Float32
-@[extern "asinhf"] opaque Float32.asinh : Float32 → Float32
-@[extern "acoshf"] opaque Float32.acosh : Float32 → Float32
-@[extern "atanhf"] opaque Float32.atanh : Float32 → Float32
-@[extern "expf"] opaque Float32.exp : Float32 → Float32
-@[extern "exp2f"] opaque Float32.exp2 : Float32 → Float32
-@[extern "logf"] opaque Float32.log : Float32 → Float32
-@[extern "log2f"] opaque Float32.log2 : Float32 → Float32
-@[extern "log10f"] opaque Float32.log10 : Float32 → Float32
-@[extern "powf"] opaque Float32.pow : Float32 → Float32 → Float32
-@[extern "sqrtf"] opaque Float32.sqrt : Float32 → Float32
-@[extern "cbrtf"] opaque Float32.cbrt : Float32 → Float32
-@[extern "ceilf"] opaque Float32.ceil : Float32 → Float32
-@[extern "floorf"] opaque Float32.floor : Float32 → Float32
-@[extern "roundf"] opaque Float32.round : Float32 → Float32
-@[extern "fabsf"] opaque Float32.abs : Float32 → Float32
-
-instance : HomogeneousPow Float32 := ⟨Float32.pow⟩
-
-instance : Min Float32 := minOfLe
-
-instance : Max Float32 := maxOfLe
-
-/--
-Efficiently computes `x * 2^i`.
--/
-@[extern "lean_float32_scaleb"]
-opaque Float32.scaleB (x : Float32) (i : @& Int) : Float32
--/

src/Init/Data/FloatArray/Basic.lean

@@ -46,8 +46,8 @@ def uget : (a : @& FloatArray) → (i : USize) → i.toNat < a.size → Float
   | ⟨ds⟩, i, h => ds[i]
 
 @[extern "lean_float_array_fget"]
-def get : (ds : @& FloatArray) → (i : @& Nat) → (h : i < ds.size := by get_elem_tactic) → Float
-  | ⟨ds⟩, i, h => ds.get i h
+def get : (ds : @& FloatArray) → (@& Fin ds.size) → Float
+  | ⟨ds⟩, i => ds.get i
 
 @[extern "lean_float_array_get"]
 def get! : (@& FloatArray) → (@& Nat) → Float
@@ -55,23 +55,23 @@ def get! : (@& FloatArray) → (@& Nat) → Float
 
 def get? (ds : FloatArray) (i : Nat) : Option Float :=
   if h : i < ds.size then
-    some (ds.get i h)
+    ds.get ⟨i, h⟩
   else
     none
 
 instance : GetElem FloatArray Nat Float fun xs i => i < xs.size where
-  getElem xs i h := xs.get i h
+  getElem xs i h := xs.get ⟨i, h⟩
 
 instance : GetElem FloatArray USize Float fun xs i => i.val < xs.size where
   getElem xs i h := xs.uget i h
 
 @[extern "lean_float_array_uset"]
-def uset : (a : FloatArray) → (i : USize) → Float → (h : i.toNat < a.size := by get_elem_tactic) → FloatArray
+def uset : (a : FloatArray) → (i : USize) → Float → i.toNat < a.size → FloatArray
   | ⟨ds⟩, i, v, h => ⟨ds.uset i v h⟩
 
 @[extern "lean_float_array_fset"]
-def set : (ds : FloatArray) → (i : @& Nat) → Float → (h : i < ds.size := by get_elem_tactic) → FloatArray
-  | ⟨ds⟩, i, d, h => ⟨ds.set i d h⟩
+def set : (ds : FloatArray) → (@& Fin ds.size) → Float → FloatArray
+  | ⟨ds⟩, i, d => ⟨ds.set i d⟩
 
 @[extern "lean_float_array_set"]
 def set! : FloatArray → (@& Nat) → Float → FloatArray
@@ -83,7 +83,7 @@ def isEmpty (s : FloatArray) : Bool :=
 partial def toList (ds : FloatArray) : List Float :=
   let rec loop (i r) :=
     if h : i < ds.size then
-      loop (i+1) (ds[i] :: r)
+      loop (i+1) (ds.get ⟨i, h⟩ :: r)
     else
       r.reverse
   loop 0 []
@@ -115,7 +115,7 @@ protected def forIn {β : Type v} {m : Type v → Type w} [Monad m] (as : FloatA
       have h' : i < as.size            := Nat.lt_of_lt_of_le (Nat.lt_succ_self i) h
       have : as.size - 1 < as.size     := Nat.sub_lt (Nat.zero_lt_of_lt h') (by decide)
       have : as.size - 1 - i < as.size := Nat.lt_of_le_of_lt (Nat.sub_le (as.size - 1) i) this
-      match (← f as[as.size - 1 - i] b) with
+      match (← f (as.get ⟨as.size - 1 - i, this⟩) b) with
       | ForInStep.done b  => pure b
       | ForInStep.yield b => loop i (Nat.le_of_lt h') b
   loop as.size (Nat.le_refl _) b
@@ -149,7 +149,7 @@ def foldlM {β : Type v} {m : Type v → Type w} [Monad m] (f : β → Float →
         match i with
         | 0    => pure b
         | i'+1 =>
-          loop i' (j+1) (← f b (as[j]'(Nat.lt_of_lt_of_le hlt h)))
+          loop i' (j+1) (← f b (as.get ⟨j, Nat.lt_of_lt_of_le hlt h⟩))
       else
         pure b
     loop (stop - start) start init

src/Init/Data/Function.lean

@@ -1,35 +0,0 @@
-/-
-Copyright (c) 2024 Lean FRO. All rights reserved.
-Released under Apache 2.0 license as described in the file LICENSE.
-Authors: Kim Morrison
--/
-
-prelude
-import Init.Core
-
-namespace Function
-
-@[inline]
-def curry : (α × β → φ) → α → β → φ := fun f a b => f (a, b)
-
-/-- Interpret a function with two arguments as a function on `α × β` -/
-@[inline]
-def uncurry : (α → β → φ) → α × β → φ := fun f a => f a.1 a.2
-
-@[simp]
-theorem curry_uncurry (f : α → β → φ) : curry (uncurry f) = f :=
-  rfl
-
-@[simp]
-theorem uncurry_curry (f : α × β → φ) : uncurry (curry f) = f :=
-  funext fun ⟨_a, _b⟩ => rfl
-
-@[simp]
-theorem uncurry_apply_pair {α β γ} (f : α → β → γ) (x : α) (y : β) : uncurry f (x, y) = f x y :=
-  rfl
-
-@[simp]
-theorem curry_apply {α β γ} (f : α × β → γ) (x : α) (y : β) : curry f x y = f (x, y) :=
-  rfl
-
-end Function

src/Init/Data/Hashable.lean

@@ -48,15 +48,9 @@ instance : Hashable UInt64 where
 instance : Hashable USize where
   hash n := n.toUInt64
 
-instance : Hashable ByteArray where
-  hash as := as.foldl (fun r a => mixHash r (hash a)) 7
-
 instance : Hashable (Fin n) where
   hash v := v.val.toUInt64
 
-instance : Hashable Char where
-  hash c := c.val.toUInt64
-
 instance : Hashable Int where
   hash
     | Int.ofNat n => UInt64.ofNat (2 * n)

src/Init/Data/Int/Bitwise/Lemmas.lean

@@ -34,8 +34,4 @@ theorem shiftRight_eq_div_pow (m : Int) (n : Nat) :
 theorem zero_shiftRight (n : Nat) : (0 : Int) >>> n = 0 := by
   simp [Int.shiftRight_eq_div_pow]
 
-@[simp]
-theorem shiftRight_zero (n : Int) : n >>> 0 = n := by
-  simp [Int.shiftRight_eq_div_pow]
-
 end Int

src/Init/Data/Int/DivMod.lean

@@ -29,8 +29,6 @@ At that time, we did not rename `div` and `mod` to `tdiv` and `tmod` (along with
 In September 2024, we decided to do this rename (with deprecations in place),
 and later we intend to rename `ediv` and `emod` to `div` and `mod`, as nearly all users will only
 ever need to use these functions and their associated lemmas.
-
-In December 2024, we removed `tdiv` and `tmod`, but have not yet renamed `ediv` and `emod`.
 -/
 
 /-! ### T-rounding division -/
@@ -73,6 +71,8 @@ def tdiv : (@& Int) → (@& Int) → Int
   | -[m +1], ofNat n => -ofNat (succ m / n)
   | -[m +1], -[n +1] =>  ofNat (succ m / succ n)
 
+@[deprecated tdiv (since := "2024-09-11")] abbrev div := tdiv
+
 /-- Integer modulo. This function uses the
   [*"T-rounding"*][t-rounding] (**T**runcation-rounding) convention
   to pair with `Int.tdiv`, meaning that `tmod a b + b * (tdiv a b) = a`
@@ -107,6 +107,8 @@ def tmod : (@& Int) → (@& Int) → Int
   | -[m +1], ofNat n => -ofNat (succ m % n)
   | -[m +1], -[n +1] => -ofNat (succ m % succ n)
 
+@[deprecated tmod (since := "2024-09-11")] abbrev mod := tmod
+
 /-! ### F-rounding division
 This pair satisfies `fdiv x y = floor (x / y)`.
 -/
@@ -249,6 +251,8 @@ instance : Mod Int where
 
 theorem ofNat_tdiv (m n : Nat) : ↑(m / n) = tdiv ↑m ↑n := rfl
 
+@[deprecated ofNat_tdiv (since := "2024-09-11")] abbrev ofNat_div := ofNat_tdiv
+
 theorem ofNat_fdiv : ∀ m n : Nat, ↑(m / n) = fdiv ↑m ↑n
   | 0, _ => by simp [fdiv]
   | succ _, _ => rfl

src/Init/Data/Int/DivModLemmas.lean

@@ -125,7 +125,7 @@ theorem eq_one_of_mul_eq_one_right {a b : Int} (H : 0 ≤ a) (H' : a * b = 1) :
   eq_one_of_dvd_one H ⟨b, H'.symm⟩
 
 theorem eq_one_of_mul_eq_one_left {a b : Int} (H : 0 ≤ b) (H' : a * b = 1) : b = 1 :=
-  eq_one_of_mul_eq_one_right (b := a) H <| by rw [Int.mul_comm, H']
+  eq_one_of_mul_eq_one_right H <| by rw [Int.mul_comm, H']
 
 /-! ### *div zero  -/
 
@@ -253,7 +253,7 @@ theorem tmod_def (a b : Int) : tmod a b = a - b * a.tdiv b := by
 
 theorem fmod_add_fdiv : ∀ a b : Int, a.fmod b + b * a.fdiv b = a
   | 0, ofNat _ | 0, -[_+1] => congrArg ofNat <| by simp
-  | succ _, ofNat _ => congrArg ofNat <| Nat.mod_add_div ..
+  | succ m, ofNat n => congrArg ofNat <| Nat.mod_add_div ..
   | succ m, -[n+1] => by
     show subNatNat (m % succ n) n + (↑(succ n * (m / succ n)) + n + 1) = (m + 1)
     rw [Int.add_comm _ n, ← Int.add_assoc, ← Int.add_assoc,
@@ -289,8 +289,8 @@ theorem fmod_eq_tmod {a b : Int} (Ha : 0 ≤ a) (Hb : 0 ≤ b) : fmod a b = tmod
 
 @[simp] protected theorem ediv_neg : ∀ a b : Int, a / (-b) = -(a / b)
   | ofNat m, 0 => show ofNat (m / 0) = -↑(m / 0) by rw [Nat.div_zero]; rfl
-  | ofNat _, -[_+1] => (Int.neg_neg _).symm
-  | ofNat _, succ _ | -[_+1], 0 | -[_+1], succ _ | -[_+1], -[_+1] => rfl
+  | ofNat m, -[n+1] => (Int.neg_neg _).symm
+  | ofNat m, succ n | -[m+1], 0 | -[m+1], succ n | -[m+1], -[n+1] => rfl
 
 theorem ediv_neg' {a b : Int} (Ha : a < 0) (Hb : 0 < b) : a / b < 0 :=
   match a, b, eq_negSucc_of_lt_zero Ha, eq_succ_of_zero_lt Hb with
@@ -339,7 +339,7 @@ theorem add_mul_ediv_right (a b : Int) {c : Int} (H : c ≠ 0) : (a + b * c) / c
       | _, ⟨k, rfl⟩, -[n+1] => show (a - n.succ * k.succ).ediv k.succ = a.ediv k.succ - n.succ by
         rw [← Int.add_sub_cancel (ediv ..), ← this, Int.sub_add_cancel]
   fun {k n} => @fun
-  | ofNat _ => congrArg ofNat <| Nat.add_mul_div_right _ _ k.succ_pos
+  | ofNat m => congrArg ofNat <| Nat.add_mul_div_right _ _ k.succ_pos
   | -[m+1] => by
     show ((n * k.succ : Nat) - m.succ : Int).ediv k.succ = n - (m / k.succ + 1 : Nat)
     by_cases h : m < n * k.succ
@@ -396,7 +396,7 @@ theorem add_mul_ediv_left (a : Int) {b : Int}
       rw [Int.mul_neg, Int.ediv_neg, Int.ediv_neg]; apply congrArg Neg.neg; apply this
   fun m k b =>
   match b, k with
-  | ofNat _, _ => congrArg ofNat (Nat.mul_div_mul_left _ _ m.succ_pos)
+  | ofNat n, k => congrArg ofNat (Nat.mul_div_mul_left _ _ m.succ_pos)
   | -[n+1], 0 => by
     rw [Int.ofNat_zero, Int.mul_zero, Int.ediv_zero, Int.ediv_zero]
   | -[n+1], succ k => congrArg negSucc <|
@@ -822,14 +822,14 @@ theorem ediv_eq_ediv_of_mul_eq_mul {a b c d : Int}
 unseal Nat.div in
 @[simp] protected theorem tdiv_neg : ∀ a b : Int, a.tdiv (-b) = -(a.tdiv b)
   | ofNat m, 0 => show ofNat (m / 0) = -↑(m / 0) by rw [Nat.div_zero]; rfl
-  | ofNat _, -[_+1] | -[_+1], succ _ => (Int.neg_neg _).symm
-  | ofNat _, succ _ | -[_+1], 0 | -[_+1], -[_+1] => rfl
+  | ofNat m, -[n+1] | -[m+1], succ n => (Int.neg_neg _).symm
+  | ofNat m, succ n | -[m+1], 0 | -[m+1], -[n+1] => rfl
 
 unseal Nat.div in
 @[simp] protected theorem neg_tdiv : ∀ a b : Int, (-a).tdiv b = -(a.tdiv b)
   | 0, n => by simp [Int.neg_zero]
-  | succ _, (n:Nat) | -[_+1], 0 | -[_+1], -[_+1] => rfl
-  | succ _, -[_+1] | -[_+1], succ _ => (Int.neg_neg _).symm
+  | succ m, (n:Nat) | -[m+1], 0 | -[m+1], -[n+1] => rfl
+  | succ m, -[n+1] | -[m+1], succ n => (Int.neg_neg _).symm
 
 protected theorem neg_tdiv_neg (a b : Int) : (-a).tdiv (-b) = a.tdiv b := by
   simp [Int.tdiv_neg, Int.neg_tdiv, Int.neg_neg]
@@ -1125,17 +1125,6 @@ theorem emod_add_bmod_congr (x : Int) (n : Nat) : Int.bmod (x%n + y) n = Int.bmo
   simp [Int.emod_def, Int.sub_eq_add_neg]
   rw [←Int.mul_neg, Int.add_right_comm,  Int.bmod_add_mul_cancel]
 
-@[simp]
-theorem emod_sub_bmod_congr (x : Int) (n : Nat) : Int.bmod (x%n - y) n = Int.bmod (x - y) n := by
-  simp only [emod_def, Int.sub_eq_add_neg]
-  rw [←Int.mul_neg, Int.add_right_comm,  Int.bmod_add_mul_cancel]
-
-@[simp]
-theorem sub_emod_bmod_congr (x : Int) (n : Nat) : Int.bmod (x - y%n) n = Int.bmod (x - y) n := by
-  simp only [emod_def]
-  rw [Int.sub_eq_add_neg, Int.neg_sub, Int.sub_eq_add_neg, ← Int.add_assoc, Int.add_right_comm,
-    Int.bmod_add_mul_cancel, Int.sub_eq_add_neg]
-
 @[simp]
 theorem emod_mul_bmod_congr (x : Int) (n : Nat) : Int.bmod (x%n * y) n = Int.bmod (x * y) n := by
   simp [Int.emod_def, Int.sub_eq_add_neg]
@@ -1151,28 +1140,9 @@ theorem bmod_add_bmod_congr : Int.bmod (Int.bmod x n + y) n = Int.bmod (x + y) n
     rw [Int.sub_eq_add_neg, Int.add_right_comm, ←Int.sub_eq_add_neg]
     simp
 
-@[simp]
-theorem bmod_sub_bmod_congr : Int.bmod (Int.bmod x n - y) n = Int.bmod (x - y) n := by
-  rw [Int.bmod_def x n]
-  split
-  next p =>
-    simp only [emod_sub_bmod_congr]
-  next p =>
-    rw [Int.sub_eq_add_neg, Int.sub_eq_add_neg, Int.add_right_comm, ←Int.sub_eq_add_neg, ← Int.sub_eq_add_neg]
-    simp [emod_sub_bmod_congr]
-
 @[simp] theorem add_bmod_bmod : Int.bmod (x + Int.bmod y n) n = Int.bmod (x + y) n := by
   rw [Int.add_comm x, Int.bmod_add_bmod_congr, Int.add_comm y]
 
-@[simp] theorem sub_bmod_bmod : Int.bmod (x - Int.bmod y n) n = Int.bmod (x - y) n := by
-  rw [Int.bmod_def y n]
-  split
-  next p =>
-    simp [sub_emod_bmod_congr]
-  next p =>
-    rw [Int.sub_eq_add_neg, Int.sub_eq_add_neg, Int.neg_add, Int.neg_neg, ← Int.add_assoc, ← Int.sub_eq_add_neg]
-    simp [sub_emod_bmod_congr]
-
 @[simp]
 theorem bmod_mul_bmod : Int.bmod (Int.bmod x n * y) n = Int.bmod (x * y) n := by
   rw [bmod_def x n]
@@ -1267,7 +1237,7 @@ theorem bmod_le {x : Int} {m : Nat} (h : 0 < m) : bmod x m ≤ (m - 1) / 2 := by
     _ = ((m + 1 - 2) + 2)/2 := by simp
     _ = (m - 1) / 2 + 1     := by
       rw [add_ediv_of_dvd_right]
-      · simp +decide only [Int.ediv_self]
+      · simp (config := {decide := true}) only [Int.ediv_self]
         congr 2
         rw [Int.add_sub_assoc, ← Int.sub_neg]
         congr
@@ -1285,7 +1255,7 @@ theorem bmod_natAbs_plus_one (x : Int) (w : 1 < x.natAbs) : bmod x (x.natAbs + 1
     simp only [bmod, ofNat_eq_coe, natAbs_ofNat, natCast_add, ofNat_one,
       emod_self_add_one (ofNat_nonneg x)]
     match x with
-    | 0 => rw [if_pos] <;> simp +decide
+    | 0 => rw [if_pos] <;> simp (config := {decide := true})
     | (x+1) =>
       rw [if_neg]
       · simp [← Int.sub_sub]
@@ -1315,3 +1285,65 @@ theorem bmod_natAbs_plus_one (x : Int) (w : 1 < x.natAbs) : bmod x (x.natAbs + 1
           all_goals decide
     · exact ofNat_nonneg x
     · exact succ_ofNat_pos (x + 1)
+
+/-! ### Deprecations -/
+
+@[deprecated Int.zero_tdiv (since := "2024-09-11")] protected abbrev zero_div := @Int.zero_tdiv
+@[deprecated Int.tdiv_zero (since := "2024-09-11")] protected abbrev div_zero := @Int.tdiv_zero
+@[deprecated tdiv_eq_ediv (since := "2024-09-11")] abbrev div_eq_ediv := @tdiv_eq_ediv
+@[deprecated fdiv_eq_tdiv (since := "2024-09-11")] abbrev fdiv_eq_div := @fdiv_eq_tdiv
+@[deprecated zero_tmod (since := "2024-09-11")] abbrev zero_mod := @zero_tmod
+@[deprecated tmod_zero (since := "2024-09-11")] abbrev mod_zero := @tmod_zero
+@[deprecated tmod_add_tdiv (since := "2024-09-11")] abbrev mod_add_div := @tmod_add_tdiv
+@[deprecated tdiv_add_tmod (since := "2024-09-11")] abbrev div_add_mod := @tdiv_add_tmod
+@[deprecated tmod_add_tdiv' (since := "2024-09-11")] abbrev mod_add_div' := @tmod_add_tdiv'
+@[deprecated tdiv_add_tmod' (since := "2024-09-11")] abbrev div_add_mod' := @tdiv_add_tmod'
+@[deprecated tmod_def (since := "2024-09-11")] abbrev mod_def := @tmod_def
+@[deprecated tmod_eq_emod (since := "2024-09-11")] abbrev mod_eq_emod := @tmod_eq_emod
+@[deprecated fmod_eq_tmod (since := "2024-09-11")] abbrev fmod_eq_mod := @fmod_eq_tmod
+@[deprecated Int.tdiv_one (since := "2024-09-11")] protected abbrev div_one := @Int.tdiv_one
+@[deprecated Int.tdiv_neg (since := "2024-09-11")] protected abbrev div_neg := @Int.tdiv_neg
+@[deprecated Int.neg_tdiv (since := "2024-09-11")] protected abbrev neg_div := @Int.neg_tdiv
+@[deprecated Int.neg_tdiv_neg (since := "2024-09-11")] protected abbrev neg_div_neg := @Int.neg_tdiv_neg
+@[deprecated Int.tdiv_nonneg (since := "2024-09-11")] protected abbrev div_nonneg := @Int.tdiv_nonneg
+@[deprecated Int.tdiv_nonpos (since := "2024-09-11")] protected abbrev div_nonpos := @Int.tdiv_nonpos
+@[deprecated Int.tdiv_eq_zero_of_lt (since := "2024-09-11")] abbrev div_eq_zero_of_lt := @Int.tdiv_eq_zero_of_lt
+@[deprecated Int.mul_tdiv_cancel (since := "2024-09-11")] protected abbrev mul_div_cancel := @Int.mul_tdiv_cancel
+@[deprecated Int.mul_tdiv_cancel_left (since := "2024-09-11")] protected abbrev mul_div_cancel_left := @Int.mul_tdiv_cancel_left
+@[deprecated Int.tdiv_self (since := "2024-09-11")] protected abbrev div_self := @Int.tdiv_self
+@[deprecated Int.mul_tdiv_cancel_of_tmod_eq_zero (since := "2024-09-11")] abbrev mul_div_cancel_of_mod_eq_zero := @Int.mul_tdiv_cancel_of_tmod_eq_zero
+@[deprecated Int.tdiv_mul_cancel_of_tmod_eq_zero (since := "2024-09-11")] abbrev div_mul_cancel_of_mod_eq_zero := @Int.tdiv_mul_cancel_of_tmod_eq_zero
+@[deprecated Int.dvd_of_tmod_eq_zero (since := "2024-09-11")] abbrev dvd_of_mod_eq_zero := @Int.dvd_of_tmod_eq_zero
+@[deprecated Int.mul_tdiv_assoc (since := "2024-09-11")] protected abbrev mul_div_assoc := @Int.mul_tdiv_assoc
+@[deprecated Int.mul_tdiv_assoc' (since := "2024-09-11")] protected abbrev mul_div_assoc' := @Int.mul_tdiv_assoc'
+@[deprecated Int.tdiv_dvd_tdiv (since := "2024-09-11")] abbrev div_dvd_div := @Int.tdiv_dvd_tdiv
+@[deprecated Int.natAbs_tdiv (since := "2024-09-11")] abbrev natAbs_div := @Int.natAbs_tdiv
+@[deprecated Int.tdiv_eq_of_eq_mul_right (since := "2024-09-11")] protected abbrev div_eq_of_eq_mul_right := @Int.tdiv_eq_of_eq_mul_right
+@[deprecated Int.eq_tdiv_of_mul_eq_right (since := "2024-09-11")] protected abbrev eq_div_of_mul_eq_right := @Int.eq_tdiv_of_mul_eq_right
+@[deprecated Int.ofNat_tmod (since := "2024-09-11")] abbrev ofNat_mod := @Int.ofNat_tmod
+@[deprecated Int.tmod_one (since := "2024-09-11")] abbrev mod_one := @Int.tmod_one
+@[deprecated Int.tmod_eq_of_lt (since := "2024-09-11")] abbrev mod_eq_of_lt := @Int.tmod_eq_of_lt
+@[deprecated Int.tmod_lt_of_pos (since := "2024-09-11")] abbrev mod_lt_of_pos := @Int.tmod_lt_of_pos
+@[deprecated Int.tmod_nonneg (since := "2024-09-11")] abbrev mod_nonneg := @Int.tmod_nonneg
+@[deprecated Int.tmod_neg (since := "2024-09-11")] abbrev mod_neg := @Int.tmod_neg
+@[deprecated Int.mul_tmod_left (since := "2024-09-11")] abbrev mul_mod_left := @Int.mul_tmod_left
+@[deprecated Int.mul_tmod_right (since := "2024-09-11")] abbrev mul_mod_right := @Int.mul_tmod_right
+@[deprecated Int.tmod_eq_zero_of_dvd (since := "2024-09-11")] abbrev mod_eq_zero_of_dvd := @Int.tmod_eq_zero_of_dvd
+@[deprecated Int.dvd_iff_tmod_eq_zero (since := "2024-09-11")] abbrev dvd_iff_mod_eq_zero := @Int.dvd_iff_tmod_eq_zero
+@[deprecated Int.neg_mul_tmod_right (since := "2024-09-11")] abbrev neg_mul_mod_right := @Int.neg_mul_tmod_right
+@[deprecated Int.neg_mul_tmod_left (since := "2024-09-11")] abbrev neg_mul_mod_left := @Int.neg_mul_tmod_left
+@[deprecated Int.tdiv_mul_cancel (since := "2024-09-11")] protected abbrev div_mul_cancel := @Int.tdiv_mul_cancel
+@[deprecated Int.mul_tdiv_cancel' (since := "2024-09-11")] protected abbrev mul_div_cancel' := @Int.mul_tdiv_cancel'
+@[deprecated Int.eq_mul_of_tdiv_eq_right (since := "2024-09-11")] protected abbrev eq_mul_of_div_eq_right := @Int.eq_mul_of_tdiv_eq_right
+@[deprecated Int.tmod_self (since := "2024-09-11")] abbrev mod_self := @Int.tmod_self
+@[deprecated Int.neg_tmod_self (since := "2024-09-11")] abbrev neg_mod_self := @Int.neg_tmod_self
+@[deprecated Int.lt_tdiv_add_one_mul_self (since := "2024-09-11")] abbrev lt_div_add_one_mul_self := @Int.lt_tdiv_add_one_mul_self
+@[deprecated Int.tdiv_eq_iff_eq_mul_right (since := "2024-09-11")] protected abbrev div_eq_iff_eq_mul_right := @Int.tdiv_eq_iff_eq_mul_right
+@[deprecated Int.tdiv_eq_iff_eq_mul_left (since := "2024-09-11")] protected abbrev div_eq_iff_eq_mul_left := @Int.tdiv_eq_iff_eq_mul_left
+@[deprecated Int.eq_mul_of_tdiv_eq_left (since := "2024-09-11")] protected abbrev eq_mul_of_div_eq_left := @Int.eq_mul_of_tdiv_eq_left
+@[deprecated Int.tdiv_eq_of_eq_mul_left (since := "2024-09-11")] protected abbrev div_eq_of_eq_mul_left := @Int.tdiv_eq_of_eq_mul_left
+@[deprecated Int.eq_zero_of_tdiv_eq_zero (since := "2024-09-11")] protected abbrev eq_zero_of_div_eq_zero := @Int.eq_zero_of_tdiv_eq_zero
+@[deprecated Int.tdiv_left_inj (since := "2024-09-11")] protected abbrev div_left_inj := @Int.tdiv_left_inj
+@[deprecated Int.tdiv_sign (since := "2024-09-11")] abbrev div_sign := @Int.tdiv_sign
+@[deprecated Int.sign_eq_tdiv_abs (since := "2024-09-11")] protected abbrev sign_eq_div_abs := @Int.sign_eq_tdiv_abs
+@[deprecated Int.tdiv_eq_ediv_of_dvd (since := "2024-09-11")] abbrev div_eq_ediv_of_dvd := @Int.tdiv_eq_ediv_of_dvd

src/Init/Data/Int/Lemmas.lean

@@ -181,12 +181,12 @@ theorem subNatNat_add_negSucc (m n k : Nat) :
       Nat.add_comm]
 
 protected theorem add_assoc : ∀ a b c : Int, a + b + c = a + (b + c)
-  | (m:Nat), (n:Nat), _ => aux1 ..
+  | (m:Nat), (n:Nat), c => aux1 ..
   | Nat.cast m, b, Nat.cast k => by
     rw [Int.add_comm, ← aux1, Int.add_comm k, aux1, Int.add_comm b]
   | a, (n:Nat), (k:Nat) => by
     rw [Int.add_comm, Int.add_comm a, ← aux1, Int.add_comm a, Int.add_comm k]
-  | -[_+1], -[_+1], (k:Nat) => aux2 ..
+  | -[m+1], -[n+1], (k:Nat) => aux2 ..
   | -[m+1], (n:Nat), -[k+1] => by
     rw [Int.add_comm, ← aux2, Int.add_comm n, ← aux2, Int.add_comm -[m+1]]
   | (m:Nat), -[n+1], -[k+1] => by
@@ -329,22 +329,22 @@ theorem toNat_sub (m n : Nat) : toNat (m - n) = m - n := by
 /- ## add/sub injectivity -/
 
 @[simp]
-protected theorem add_left_inj {i j : Int} (k : Int) : (i + k = j + k) ↔ i = j := by
+protected theorem add_right_inj {i j : Int} (k : Int) : (i + k = j + k) ↔ i = j := by
   apply Iff.intro
   · intro p
     rw [←Int.add_sub_cancel i k, ←Int.add_sub_cancel j k, p]
   · exact congrArg (· + k)
 
 @[simp]
-protected theorem add_right_inj {i j : Int} (k : Int) : (k + i = k + j) ↔ i = j := by
+protected theorem add_left_inj {i j : Int} (k : Int) : (k + i = k + j) ↔ i = j := by
   simp [Int.add_comm k]
 
 @[simp]
-protected theorem sub_right_inj {i j : Int} (k : Int) : (k - i = k - j) ↔ i = j := by
+protected theorem sub_left_inj {i j : Int} (k : Int) : (k - i = k - j) ↔ i = j := by
   simp [Int.sub_eq_add_neg, Int.neg_inj]
 
 @[simp]
-protected theorem sub_left_inj {i j : Int} (k : Int) : (i - k = j - k) ↔ i = j := by
+protected theorem sub_right_inj {i j : Int} (k : Int) : (i - k = j - k) ↔ i = j := by
   simp [Int.sub_eq_add_neg]
 
 /- ## Ring properties -/

src/Init/Data/Int/Order.lean

@@ -512,8 +512,8 @@ theorem toNat_add_nat {a : Int} (ha : 0 ≤ a) (n : Nat) : (a + n).toNat = a.toN
 
 @[simp] theorem pred_toNat : ∀ i : Int, (i - 1).toNat = i.toNat - 1
   | 0 => rfl
-  | (_+1:Nat) => by simp [ofNat_add]
-  | -[_+1] => rfl
+  | (n+1:Nat) => by simp [ofNat_add]
+  | -[n+1] => rfl
 
 theorem toNat_sub_toNat_neg : ∀ n : Int, ↑n.toNat - ↑(-n).toNat = n
   | 0 => rfl
@@ -1007,9 +1007,9 @@ theorem sign_eq_neg_one_iff_neg {a : Int} : sign a = -1 ↔ a < 0 :=
   match x with
   | 0 => rfl
   | .ofNat (_ + 1) =>
-    simp +decide only [sign, true_iff]
+    simp (config := { decide := true }) only [sign, true_iff]
     exact Int.le_add_one (ofNat_nonneg _)
-  | .negSucc _ => simp +decide [sign]
+  | .negSucc _ => simp (config := { decide := true }) [sign]
 
 theorem mul_sign : ∀ i : Int, i * sign i = natAbs i
   | succ _ => Int.mul_one _

src/Init/Data/Int/Pow.lean

@@ -5,7 +5,6 @@ Authors: Jeremy Avigad, Deniz Aydin, Floris van Doorn, Mario Carneiro
 -/
 prelude
 import Init.Data.Int.Lemmas
-import Init.Data.Nat.Lemmas
 
 namespace Int
 
@@ -36,24 +35,10 @@ theorem pow_le_pow_of_le_right {n : Nat} (hx : n > 0) {i : Nat} : ∀ {j}, i ≤
 theorem pos_pow_of_pos {n : Nat} (m : Nat) (h : 0 < n) : 0 < n^m :=
   pow_le_pow_of_le_right h (Nat.zero_le _)
 
-@[norm_cast]
 theorem natCast_pow (b n : Nat) : ((b^n : Nat) : Int) = (b : Int) ^ n := by
   match n with
   | 0 => rfl
   | n + 1 =>
     simp only [Nat.pow_succ, Int.pow_succ, natCast_mul, natCast_pow _ n]
 
-@[simp]
-protected theorem two_pow_pred_sub_two_pow {w : Nat} (h : 0 < w) :
-    ((2 ^ (w - 1) : Nat) - (2 ^ w : Nat) : Int) = - ((2 ^ (w - 1) : Nat) : Int) := by
-  rw [← Nat.two_pow_pred_add_two_pow_pred h]
-  omega
-
-@[simp]
-protected theorem two_pow_pred_sub_two_pow' {w : Nat} (h : 0 < w) :
-    (2 : Int) ^ (w - 1) - (2 : Int) ^ w = - (2 : Int) ^ (w - 1) := by
-  norm_cast
-  rw [← Nat.two_pow_pred_add_two_pow_pred h]
-  simp [h]
-
 end Int

src/Init/Data/List.lean

@@ -23,8 +23,3 @@ import Init.Data.List.TakeDrop
 import Init.Data.List.Zip
 import Init.Data.List.Perm
 import Init.Data.List.Sort
-import Init.Data.List.ToArray
-import Init.Data.List.ToArrayImpl
-import Init.Data.List.MapIdx
-import Init.Data.List.OfFn
-import Init.Data.List.FinRange

src/Init/Data/List/Attach.lean

@@ -13,7 +13,7 @@ namespace List
   `a : α` satisfying `P`, then `pmap f l h` is essentially the same as `map f l`
   but is defined only when all members of `l` satisfy `P`, using the proof
   to apply `f`. -/
-def pmap {P : α → Prop} (f : ∀ a, P a → β) : ∀ l : List α, (H : ∀ a ∈ l, P a) → List β
+@[simp] def pmap {P : α → Prop} (f : ∀ a, P a → β) : ∀ l : List α, (H : ∀ a ∈ l, P a) → List β
   | [], _ => []
   | a :: l, H => f a (forall_mem_cons.1 H).1 :: pmap f l (forall_mem_cons.1 H).2
 
@@ -46,11 +46,6 @@ Unsafe implementation of `attachWith`, taking advantage of the fact that the rep
   | cons _ L', hL' => congrArg _ <| go L' fun _ hx => hL' (.tail _ hx)
   exact go L h'
 
-@[simp] theorem pmap_nil {P : α → Prop} (f : ∀ a, P a → β) : pmap f [] (by simp) = [] := rfl
-
-@[simp] theorem pmap_cons {P : α → Prop} (f : ∀ a, P a → β) (a : α) (l : List α) (h : ∀ b ∈ a :: l, P b) :
-    pmap f (a :: l) h = f a (forall_mem_cons.1 h).1 :: pmap f l (forall_mem_cons.1 h).2 := rfl
-
 @[simp] theorem attach_nil : ([] : List α).attach = [] := rfl
 
 @[simp] theorem attachWith_nil : ([] : List α).attachWith P H = [] := rfl
@@ -78,7 +73,7 @@ theorem map_pmap {p : α → Prop} (g : β → γ) (f : ∀ a, p a → β) (l H)
   · simp only [*, pmap, map]
 
 theorem pmap_map {p : β → Prop} (g : ∀ b, p b → γ) (f : α → β) (l H) :
-    pmap g (map f l) H = pmap (fun a h => g (f a) h) l fun _ h => H _ (mem_map_of_mem _ h) := by
+    pmap g (map f l) H = pmap (fun a h => g (f a) h) l fun a h => H _ (mem_map_of_mem _ h) := by
   induction l
   · rfl
   · simp only [*, pmap, map]
@@ -89,7 +84,7 @@ theorem attach_congr {l₁ l₂ : List α} (h : l₁ = l₂) :
   simp
 
 theorem attachWith_congr {l₁ l₂ : List α} (w : l₁ = l₂) {P : α → Prop} {H : ∀ x ∈ l₁, P x} :
-    l₁.attachWith P H = l₂.attachWith P fun _ h => H _ (w ▸ h) := by
+    l₁.attachWith P H = l₂.attachWith P fun x h => H _ (w ▸ h) := by
   subst w
   simp
 
@@ -153,7 +148,7 @@ theorem mem_pmap_of_mem {p : α → Prop} {f : ∀ a, p a → β} {l H} {a} (h :
   exact ⟨a, h, rfl⟩
 
 @[simp]
-theorem length_pmap {p : α → Prop} {f : ∀ a, p a → β} {l H} : (pmap f l H).length = l.length := by
+theorem length_pmap {p : α → Prop} {f : ∀ a, p a → β} {l H} : length (pmap f l H) = length l := by
   induction l
   · rfl
   · simp only [*, pmap, length]
@@ -174,13 +169,6 @@ theorem pmap_ne_nil_iff {P : α → Prop} (f : (a : α) → P a → β) {xs : Li
     (H : ∀ (a : α), a ∈ xs → P a) : xs.pmap f H ≠ [] ↔ xs ≠ [] := by
   simp
 
-theorem pmap_eq_self {l : List α} {p : α → Prop} (hp : ∀ (a : α), a ∈ l → p a)
-    (f : (a : α) → p a → α) : l.pmap f hp = l ↔ ∀ a (h : a ∈ l), f a (hp a h) = a := by
-  rw [pmap_eq_map_attach]
-  conv => lhs; rhs; rw [← attach_map_subtype_val l]
-  rw [map_inj_left]
-  simp
-
 @[simp]
 theorem attach_eq_nil_iff {l : List α} : l.attach = [] ↔ l = [] :=
   pmap_eq_nil_iff
@@ -204,7 +192,7 @@ theorem attachWith_ne_nil_iff {l : List α} {P : α → Prop} {H : ∀ a ∈ l,
 
 @[simp]
 theorem getElem?_pmap {p : α → Prop} (f : ∀ a, p a → β) {l : List α} (h : ∀ a ∈ l, p a) (n : Nat) :
-    (pmap f l h)[n]? = Option.pmap f l[n]? fun x H => h x (mem_of_getElem? H) := by
+    (pmap f l h)[n]? = Option.pmap f l[n]? fun x H => h x (getElem?_mem H) := by
   induction l generalizing n with
   | nil => simp
   | cons hd tl hl =>
@@ -220,7 +208,7 @@ theorem getElem?_pmap {p : α → Prop} (f : ∀ a, p a → β) {l : List α} (h
       · simp_all
 
 theorem get?_pmap {p : α → Prop} (f : ∀ a, p a → β) {l : List α} (h : ∀ a ∈ l, p a) (n : Nat) :
-    get? (pmap f l h) n = Option.pmap f (get? l n) fun x H => h x (mem_of_get? H) := by
+    get? (pmap f l h) n = Option.pmap f (get? l n) fun x H => h x (get?_mem H) := by
   simp only [get?_eq_getElem?]
   simp [getElem?_pmap, h]
 
@@ -243,18 +231,18 @@ theorem get_pmap {p : α → Prop} (f : ∀ a, p a → β) {l : List α} (h :
     (hn : n < (pmap f l h).length) :
     get (pmap f l h) ⟨n, hn⟩ =
       f (get l ⟨n, @length_pmap _ _ p f l h ▸ hn⟩)
-        (h _ (getElem_mem (@length_pmap _ _ p f l h ▸ hn))) := by
+        (h _ (get_mem l n (@length_pmap _ _ p f l h ▸ hn))) := by
   simp only [get_eq_getElem]
   simp [getElem_pmap]
 
 @[simp]
 theorem getElem?_attachWith {xs : List α} {i : Nat} {P : α → Prop} {H : ∀ a ∈ xs, P a} :
-    (xs.attachWith P H)[i]? = xs[i]?.pmap Subtype.mk (fun _ a => H _ (mem_of_getElem? a)) :=
+    (xs.attachWith P H)[i]? = xs[i]?.pmap Subtype.mk (fun _ a => H _ (getElem?_mem a)) :=
   getElem?_pmap ..
 
 @[simp]
 theorem getElem?_attach {xs : List α} {i : Nat} :
-    xs.attach[i]? = xs[i]?.pmap Subtype.mk (fun _ a => mem_of_getElem? a) :=
+    xs.attach[i]? = xs[i]?.pmap Subtype.mk (fun _ a => getElem?_mem a) :=
   getElem?_attachWith
 
 @[simp]
@@ -338,7 +326,6 @@ This is useful when we need to use `attach` to show termination.
 
 Unfortunately this can't be applied by `simp` because of the higher order unification problem,
 and even when rewriting we need to specify the function explicitly.
-See however `foldl_subtype` below.
 -/
 theorem foldl_attach (l : List α) (f : β → α → β) (b : β) :
     l.attach.foldl (fun acc t => f acc t.1) b = l.foldl f b := by
@@ -354,7 +341,6 @@ This is useful when we need to use `attach` to show termination.
 
 Unfortunately this can't be applied by `simp` because of the higher order unification problem,
 and even when rewriting we need to specify the function explicitly.
-See however `foldr_subtype` below.
 -/
 theorem foldr_attach (l : List α) (f : α → β → β) (b : β) :
     l.attach.foldr (fun t acc => f t.1 acc) b = l.foldr f b := by
@@ -367,7 +353,7 @@ theorem attach_map {l : List α} (f : α → β) :
   induction l <;> simp [*]
 
 theorem attachWith_map {l : List α} (f : α → β) {P : β → Prop} {H : ∀ (b : β), b ∈ l.map f → P b} :
-    (l.map f).attachWith P H = (l.attachWith (P ∘ f) (fun _ h => H _ (mem_map_of_mem f h))).map
+    (l.map f).attachWith P H = (l.attachWith (P ∘ f) (fun a h => H _ (mem_map_of_mem f h))).map
       fun ⟨x, h⟩ => ⟨f x, h⟩ := by
   induction l <;> simp [*]
 
@@ -459,16 +445,16 @@ theorem pmap_append' {p : α → Prop} (f : ∀ a : α, p a → β) (l₁ l₂ :
   pmap_append f l₁ l₂ _
 
 @[simp] theorem attach_append (xs ys : List α) :
-    (xs ++ ys).attach = xs.attach.map (fun ⟨x, h⟩ => ⟨x, mem_append_left ys h⟩) ++
-      ys.attach.map fun ⟨x, h⟩ => ⟨x, mem_append_right xs h⟩ := by
+    (xs ++ ys).attach = xs.attach.map (fun ⟨x, h⟩ => ⟨x, mem_append_of_mem_left ys h⟩) ++
+      ys.attach.map fun ⟨x, h⟩ => ⟨x, mem_append_of_mem_right xs h⟩ := by
   simp only [attach, attachWith, pmap, map_pmap, pmap_append]
   congr 1 <;>
   exact pmap_congr_left _ fun _ _ _ _ => rfl
 
 @[simp] theorem attachWith_append {P : α → Prop} {xs ys : List α}
     {H : ∀ (a : α), a ∈ xs ++ ys → P a} :
-    (xs ++ ys).attachWith P H = xs.attachWith P (fun a h => H a (mem_append_left ys h)) ++
-      ys.attachWith P (fun a h => H a (mem_append_right xs h)) := by
+    (xs ++ ys).attachWith P H = xs.attachWith P (fun a h => H a (mem_append_of_mem_left ys h)) ++
+      ys.attachWith P (fun a h => H a (mem_append_of_mem_right xs h)) := by
   simp only [attachWith, attach_append, map_pmap, pmap_append]
 
 @[simp] theorem pmap_reverse {P : α → Prop} (f : (a : α) → P a → β) (xs : List α)
@@ -562,144 +548,4 @@ theorem count_attachWith [DecidableEq α] {p : α → Prop} (l : List α) (H :
     (l.attachWith p H).count a = l.count ↑a :=
   Eq.trans (countP_congr fun _ _ => by simp [Subtype.ext_iff]) <| countP_attachWith _ _ _
 
-/-! ## unattach
-
-`List.unattach` is the (one-sided) inverse of `List.attach`. It is a synonym for `List.map Subtype.val`.
-
-We use it by providing a simp lemma `l.attach.unattach = l`, and simp lemmas which recognize higher order
-functions applied to `l : List { x // p x }` which only depend on the value, not the predicate, and rewrite these
-in terms of a simpler function applied to `l.unattach`.
-
-Further, we provide simp lemmas that push `unattach` inwards.
--/
-
-/--
-A synonym for `l.map (·.val)`. Mostly this should not be needed by users.
-It is introduced as an intermediate step by lemmas such as `map_subtype`,
-and is ideally subsequently simplified away by `unattach_attach`.
-
-If not, usually the right approach is `simp [List.unattach, -List.map_subtype]` to unfold.
--/
-def unattach {α : Type _} {p : α → Prop} (l : List { x // p x }) := l.map (·.val)
-
-@[simp] theorem unattach_nil {p : α → Prop} : ([] : List { x // p x }).unattach = [] := rfl
-@[simp] theorem unattach_cons {p : α → Prop} {a : { x // p x }} {l : List { x // p x }} :
-  (a :: l).unattach = a.val :: l.unattach := rfl
-
-@[simp] theorem length_unattach {p : α → Prop} {l : List { x // p x }} :
-    l.unattach.length = l.length := by
-  unfold unattach
-  simp
-
-@[simp] theorem unattach_attach {l : List α} : l.attach.unattach = l := by
-  unfold unattach
-  induction l with
-  | nil => simp
-  | cons a l ih => simp [ih, Function.comp_def]
-
-@[simp] theorem unattach_attachWith {p : α → Prop} {l : List α}
-    {H : ∀ a ∈ l, p a} :
-    (l.attachWith p H).unattach = l := by
-  unfold unattach
-  induction l with
-  | nil => simp
-  | cons a l ih => simp [ih, Function.comp_def]
-
-@[simp] theorem getElem?_unattach {p : α → Prop} {l : List { x // p x }} (i : Nat) :
-    l.unattach[i]? = l[i]?.map Subtype.val := by
-  simp [unattach]
-
-@[simp] theorem getElem_unattach
-    {p : α → Prop} {l : List { x // p x }} (i : Nat) (h : i < l.unattach.length) :
-    l.unattach[i] = (l[i]'(by simpa using h)).1 := by
-  simp [unattach]
-
-/-! ### Recognizing higher order functions on subtypes using a function that only depends on the value. -/
-
-/--
-This lemma identifies folds over lists of subtypes, where the function only depends on the value, not the proposition,
-and simplifies these to the function directly taking the value.
--/
-@[simp] theorem foldl_subtype {p : α → Prop} {l : List { x // p x }}
-    {f : β → { x // p x } → β} {g : β → α → β} {x : β}
-    {hf : ∀ b x h, f b ⟨x, h⟩ = g b x} :
-    l.foldl f x = l.unattach.foldl g x := by
-  unfold unattach
-  induction l generalizing x with
-  | nil => simp
-  | cons a l ih => simp [ih, hf]
-
-/--
-This lemma identifies folds over lists of subtypes, where the function only depends on the value, not the proposition,
-and simplifies these to the function directly taking the value.
--/
-@[simp] theorem foldr_subtype {p : α → Prop} {l : List { x // p x }}
-    {f : { x // p x } → β → β} {g : α → β → β} {x : β}
-    {hf : ∀ x h b, f ⟨x, h⟩ b = g x b} :
-    l.foldr f x = l.unattach.foldr g x := by
-  unfold unattach
-  induction l generalizing x with
-  | nil => simp
-  | cons a l ih => simp [ih, hf]
-
-/--
-This lemma identifies maps over lists of subtypes, where the function only depends on the value, not the proposition,
-and simplifies these to the function directly taking the value.
--/
-@[simp] theorem map_subtype {p : α → Prop} {l : List { x // p x }}
-    {f : { x // p x } → β} {g : α → β} {hf : ∀ x h, f ⟨x, h⟩ = g x} :
-    l.map f = l.unattach.map g := by
-  unfold unattach
-  induction l with
-  | nil => simp
-  | cons a l ih => simp [ih, hf]
-
-@[simp] theorem filterMap_subtype {p : α → Prop} {l : List { x // p x }}
-    {f : { x // p x } → Option β} {g : α → Option β} {hf : ∀ x h, f ⟨x, h⟩ = g x} :
-    l.filterMap f = l.unattach.filterMap g := by
-  unfold unattach
-  induction l with
-  | nil => simp
-  | cons a l ih => simp [ih, hf, filterMap_cons]
-
-@[simp] theorem flatMap_subtype {p : α → Prop} {l : List { x // p x }}
-    {f : { x // p x } → List β} {g : α → List β} {hf : ∀ x h, f ⟨x, h⟩ = g x} :
-    (l.flatMap f) = l.unattach.flatMap g := by
-  unfold unattach
-  induction l with
-  | nil => simp
-  | cons a l ih => simp [ih, hf]
-
-@[deprecated flatMap_subtype (since := "2024-10-16")] abbrev bind_subtype := @flatMap_subtype
-
-@[simp] theorem unattach_filter {p : α → Prop} {l : List { x // p x }}
-    {f : { x // p x } → Bool} {g : α → Bool} {hf : ∀ x h, f ⟨x, h⟩ = g x} :
-    (l.filter f).unattach = l.unattach.filter g := by
-  induction l with
-  | nil => simp
-  | cons a l ih =>
-    simp only [filter_cons, hf, unattach_cons]
-    split <;> simp [ih]
-
-/-! ### Simp lemmas pushing `unattach` inwards. -/
-
-@[simp] theorem unattach_reverse {p : α → Prop} {l : List { x // p x }} :
-    l.reverse.unattach = l.unattach.reverse := by
-  simp [unattach, -map_subtype]
-
-@[simp] theorem unattach_append {p : α → Prop} {l₁ l₂ : List { x // p x }} :
-    (l₁ ++ l₂).unattach = l₁.unattach ++ l₂.unattach := by
-  simp [unattach, -map_subtype]
-
-@[simp] theorem unattach_flatten {p : α → Prop} {l : List (List { x // p x })} :
-    l.flatten.unattach = (l.map unattach).flatten := by
-  unfold unattach
-  induction l <;> simp_all
-
-@[deprecated unattach_flatten (since := "2024-10-14")] abbrev unattach_join := @unattach_flatten
-
-@[simp] theorem unattach_replicate {p : α → Prop} {n : Nat} {x : { x // p x }} :
-    (List.replicate n x).unattach = List.replicate n x.1 := by
-  simp [unattach, -map_subtype]
-
 end List

src/Init/Data/List/Basic.lean

@@ -29,23 +29,22 @@ The operations are organized as follow:
 * Lexicographic ordering: `lt`, `le`, and instances.
 * Head and tail operators: `head`, `head?`, `headD?`, `tail`, `tail?`, `tailD`.
 * Basic operations:
-  `map`, `filter`, `filterMap`, `foldr`, `append`, `flatten`, `pure`, `flatMap`, `replicate`, and
+  `map`, `filter`, `filterMap`, `foldr`, `append`, `join`, `pure`, `bind`, `replicate`, and
   `reverse`.
 * Additional functions defined in terms of these: `leftpad`, `rightPad`, and `reduceOption`.
-* Operations using indexes: `mapIdx`.
 * List membership: `isEmpty`, `elem`, `contains`, `mem` (and the `∈` notation),
   and decidability for predicates quantifying over membership in a `List`.
 * Sublists: `take`, `drop`, `takeWhile`, `dropWhile`, `partition`, `dropLast`,
   `isPrefixOf`, `isPrefixOf?`, `isSuffixOf`, `isSuffixOf?`, `Subset`, `Sublist`,
   `rotateLeft` and `rotateRight`.
-* Manipulating elements: `replace`, `modify`, `insert`, `insertIdx`, `erase`, `eraseP`, `eraseIdx`.
+* Manipulating elements: `replace`, `insert`, `erase`, `eraseP`, `eraseIdx`.
 * Finding elements: `find?`, `findSome?`, `findIdx`, `indexOf`, `findIdx?`, `indexOf?`,
  `countP`, `count`, and `lookup`.
 * Logic: `any`, `all`, `or`, and `and`.
 * Zippers: `zipWith`, `zip`, `zipWithAll`, and `unzip`.
 * Ranges and enumeration: `range`, `iota`, `enumFrom`, and `enum`.
-* Minima and maxima: `min?` and `max?`.
-* Other functions: `intersperse`, `intercalate`, `eraseDups`, `eraseReps`, `span`, `splitBy`,
+* Minima and maxima: `minimum?` and `maximum?`.
+* Other functions: `intersperse`, `intercalate`, `eraseDups`, `eraseReps`, `span`, `groupBy`,
   `removeAll`
   (currently these functions are mostly only used in meta code,
   and do not have API suitable for verification).
@@ -122,11 +121,6 @@ protected def beq [BEq α] : List α → List α → Bool
   | a::as, b::bs => a == b && List.beq as bs
   | _,     _     => false
 
-@[simp] theorem beq_nil_nil [BEq α] : List.beq ([] : List α) ([] : List α) = true := rfl
-@[simp] theorem beq_cons_nil [BEq α] (a : α) (as : List α) : List.beq (a::as) [] = false := rfl
-@[simp] theorem beq_nil_cons [BEq α] (a : α) (as : List α) : List.beq [] (a::as) = false := rfl
-theorem beq_cons₂ [BEq α] (a b : α) (as bs : List α) : List.beq (a::as) (b::bs) = (a == b && List.beq as bs) := rfl
-
 instance [BEq α] : BEq (List α) := ⟨List.beq⟩
 
 instance [BEq α] [LawfulBEq α] : LawfulBEq (List α) where
@@ -224,14 +218,14 @@ def get? : (as : List α) → (i : Nat) → Option α
 
 theorem ext_get? : ∀ {l₁ l₂ : List α}, (∀ n, l₁.get? n = l₂.get? n) → l₁ = l₂
   | [], [], _ => rfl
-  | _ :: _, [], h => nomatch h 0
-  | [], _ :: _, h => nomatch h 0
+  | a :: l₁, [], h => nomatch h 0
+  | [], a' :: l₂, h => nomatch h 0
   | a :: l₁, a' :: l₂, h => by
     have h0 : some a = some a' := h 0
     injection h0 with aa; simp only [aa, ext_get? fun n => h (n+1)]
 
 /-- Deprecated alias for `ext_get?`. The preferred extensionality theorem is now `ext_getElem?`. -/
-@[deprecated ext_get? (since := "2024-06-07")] abbrev ext := @ext_get?
+@[deprecated (since := "2024-06-07")] abbrev ext := @ext_get?
 
 /-! ### getD -/
 
@@ -374,7 +368,7 @@ def tailD (list fallback : List α) : List α :=
 /-! ## Basic `List` operations.
 
 We define the basic functional programming operations on `List`:
-`map`, `filter`, `filterMap`, `foldr`, `append`, `flatten`, `pure`, `bind`, `replicate`, and `reverse`.
+`map`, `filter`, `filterMap`, `foldr`, `append`, `join`, `pure`, `bind`, `replicate`, and `reverse`.
 -/
 
 /-! ### map -/
@@ -548,53 +542,41 @@ theorem reverseAux_eq_append (as bs : List α) : reverseAux as bs = reverseAux a
   simp [reverse, reverseAux]
   rw [← reverseAux_eq_append]
 
-/-! ### flatten -/
+/-! ### join -/
 
 /--
-`O(|flatten L|)`. `flatten L` concatenates all the lists in `L` into one list.
-* `flatten [[a], [], [b, c], [d, e, f]] = [a, b, c, d, e, f]`
+`O(|join L|)`. `join L` concatenates all the lists in `L` into one list.
+* `join [[a], [], [b, c], [d, e, f]] = [a, b, c, d, e, f]`
 -/
-def flatten : List (List α) → List α
+def join : List (List α) → List α
   | []      => []
-  | a :: as => a ++ flatten as
+  | a :: as => a ++ join as
 
-@[simp] theorem flatten_nil : List.flatten ([] : List (List α)) = [] := rfl
-@[simp] theorem flatten_cons : (l :: ls).flatten = l ++ ls.flatten := rfl
+@[simp] theorem join_nil : List.join ([] : List (List α)) = [] := rfl
+@[simp] theorem join_cons : (l :: ls).join = l ++ ls.join := rfl
 
-@[deprecated flatten (since := "2024-10-14"), inherit_doc flatten] abbrev join := @flatten
+/-! ### pure -/
 
-/-! ### singleton -/
+/-- `pure x = [x]` is the `pure` operation of the list monad. -/
+@[inline] protected def pure {α : Type u} (a : α) : List α := [a]
 
-/-- `singleton x = [x]`. -/
-@[inline] protected def singleton {α : Type u} (a : α) : List α := [a]
-
-set_option linter.missingDocs false in
-@[deprecated singleton (since := "2024-10-16")] protected abbrev pure := @singleton
-
-/-! ### flatMap -/
+/-! ### bind -/
 
 /--
-`flatMap xs f` applies `f` to each element of `xs`
+`bind xs f` is the bind operation of the list monad. It applies `f` to each element of `xs`
 to get a list of lists, and then concatenates them all together.
 * `[2, 3, 2].bind range = [0, 1, 0, 1, 2, 0, 1]`
 -/
-@[inline] def flatMap {α : Type u} {β : Type v} (a : List α) (b : α → List β) : List β := flatten (map b a)
+@[inline] protected def bind {α : Type u} {β : Type v} (a : List α) (b : α → List β) : List β := join (map b a)
 
-@[simp] theorem flatMap_nil (f : α → List β) : List.flatMap [] f = [] := by simp [flatten, List.flatMap]
-@[simp] theorem flatMap_cons x xs (f : α → List β) :
-  List.flatMap (x :: xs) f = f x ++ List.flatMap xs f := by simp [flatten, List.flatMap]
+@[simp] theorem bind_nil (f : α → List β) : List.bind [] f = [] := by simp [join, List.bind]
+@[simp] theorem bind_cons x xs (f : α → List β) :
+  List.bind (x :: xs) f = f x ++ List.bind xs f := by simp [join, List.bind]
 
 set_option linter.missingDocs false in
-@[deprecated flatMap (since := "2024-10-16")] abbrev bind := @flatMap
+@[deprecated bind_nil (since := "2024-06-15")] abbrev nil_bind := @bind_nil
 set_option linter.missingDocs false in
-@[deprecated flatMap_nil (since := "2024-10-16")] abbrev nil_flatMap := @flatMap_nil
-set_option linter.missingDocs false in
-@[deprecated flatMap_cons (since := "2024-10-16")] abbrev cons_flatMap := @flatMap_cons
-
-set_option linter.missingDocs false in
-@[deprecated flatMap_nil (since := "2024-06-15")] abbrev nil_bind := @flatMap_nil
-set_option linter.missingDocs false in
-@[deprecated flatMap_cons (since := "2024-06-15")] abbrev cons_bind := @flatMap_cons
+@[deprecated bind_cons (since := "2024-06-15")] abbrev cons_bind := @bind_cons
 
 /-! ### replicate -/
 
@@ -666,14 +648,10 @@ def isEmpty : List α → Bool
 /-! ### elem -/
 
 /--
-`O(|l|)`.
-`l.contains a` or `elem a l` is true if there is an element in `l` equal (according to `==`) to `a`.
+`O(|l|)`. `elem a l` or `l.contains a` is true if there is an element in `l` equal to `a`.
 
-* `[1, 4, 2, 3, 3, 7].contains 3 = true`
-* `[1, 4, 2, 3, 3, 7].contains 5 = false`
-
-The preferred simp normal form is `l.contains a`, and when `LawfulBEq α` is available,
-`l.contains a = true ↔ a ∈ l` and `l.contains a = false ↔ a ∉ l`.
+* `elem 3 [1, 4, 2, 3, 3, 7] = true`
+* `elem 5 [1, 4, 2, 3, 3, 7] = false`
 -/
 def elem [BEq α] (a : α) : List α → Bool
   | []    => false
@@ -686,7 +664,7 @@ theorem elem_cons [BEq α] {a : α} :
     (b::bs).elem a = match a == b with | true => true | false => bs.elem a := rfl
 
 /-- `notElem a l` is `!(elem a l)`. -/
-@[deprecated "Use `!(elem a l)` instead."(since := "2024-06-15")]
+@[deprecated (since := "2024-06-15")]
 def notElem [BEq α] (a : α) (as : List α) : Bool :=
   !(as.elem a)
 
@@ -730,13 +708,13 @@ theorem elem_eq_true_of_mem [BEq α] [LawfulBEq α] {a : α} {as : List α} (h :
 instance [BEq α] [LawfulBEq α] (a : α) (as : List α) : Decidable (a ∈ as) :=
   decidable_of_decidable_of_iff (Iff.intro mem_of_elem_eq_true elem_eq_true_of_mem)
 
-theorem mem_append_left {a : α} {as : List α} (bs : List α) : a ∈ as → a ∈ as ++ bs := by
+theorem mem_append_of_mem_left {a : α} {as : List α} (bs : List α) : a ∈ as → a ∈ as ++ bs := by
   intro h
   induction h with
   | head => apply Mem.head
   | tail => apply Mem.tail; assumption
 
-theorem mem_append_right {b : α} {bs : List α} (as : List α) : b ∈ bs → b ∈ as ++ bs := by
+theorem mem_append_of_mem_right {b : α} {bs : List α} (as : List α) : b ∈ bs → b ∈ as ++ bs := by
   intro h
   induction as with
   | nil  => simp [h]
@@ -1117,50 +1095,12 @@ theorem replace_cons [BEq α] {a : α} :
     (a::as).replace b c = match b == a with | true => c::as | false => a :: replace as b c :=
   rfl
 
-/-! ### modify -/
-
-/--
-Apply a function to the nth tail of `l`. Returns the input without
-using `f` if the index is larger than the length of the List.
-```
-modifyTailIdx f 2 [a, b, c] = [a, b] ++ f [c]
-```
--/
-@[simp] def modifyTailIdx (f : List α → List α) : Nat → List α → List α
-  | 0, l => f l
-  | _+1, [] => []
-  | n+1, a :: l => a :: modifyTailIdx f n l
-
-/-- Apply `f` to the head of the list, if it exists. -/
-@[inline] def modifyHead (f : α → α) : List α → List α
-  | [] => []
-  | a :: l => f a :: l
-
-@[simp] theorem modifyHead_nil (f : α → α) : [].modifyHead f = [] := by rw [modifyHead]
-@[simp] theorem modifyHead_cons (a : α) (l : List α) (f : α → α) :
-    (a :: l).modifyHead f = f a :: l := by rw [modifyHead]
-
-/--
-Apply `f` to the nth element of the list, if it exists, replacing that element with the result.
--/
-def modify (f : α → α) : Nat → List α → List α :=
-  modifyTailIdx (modifyHead f)
-
 /-! ### insert -/
 
 /-- Inserts an element into a list without duplication. -/
 @[inline] protected def insert [BEq α] (a : α) (l : List α) : List α :=
   if l.elem a then l else a :: l
 
-/--
-`insertIdx n a l` inserts `a` into the list `l` after the first `n` elements of `l`
-```
-insertIdx 2 1 [1, 2, 3, 4] = [1, 2, 1, 3, 4]
-```
--/
-def insertIdx (n : Nat) (a : α) : List α → List α :=
-  modifyTailIdx (cons a) n
-
 /-! ### erase -/
 
 /--
@@ -1431,10 +1371,10 @@ def zipWithAll (f : Option α → Option β → γ) : List α → List β → Li
   | a :: as, [] => (a :: as).map fun a => f (some a) none
   | a :: as, b :: bs => f a b :: zipWithAll f as bs
 
-@[simp] theorem zipWithAll_nil :
+@[simp] theorem zipWithAll_nil_right :
     zipWithAll f as [] = as.map fun a => f (some a) none := by
   cases as <;> rfl
-@[simp] theorem nil_zipWithAll :
+@[simp] theorem zipWithAll_nil_left :
     zipWithAll f [] bs = bs.map fun b => f none (some b) := rfl
 @[simp] theorem zipWithAll_cons_cons :
     zipWithAll f (a :: as) (b :: bs) = f (some a) (some b) :: zipWithAll f as bs := rfl
@@ -1455,25 +1395,12 @@ def unzip : List (α × β) → List α × List β
 
 /-! ## Ranges and enumeration -/
 
-/-- Sum of a list.
-
-`List.sum [a, b, c] = a + (b + (c + 0))` -/
-def sum {α} [Add α] [Zero α] : List α → α :=
-  foldr (· + ·) 0
-
-@[simp] theorem sum_nil [Add α] [Zero α] : ([] : List α).sum = 0 := rfl
-@[simp] theorem sum_cons [Add α] [Zero α] {a : α} {l : List α} : (a::l).sum = a + l.sum := rfl
-
 /-- Sum of a list of natural numbers. -/
-@[deprecated List.sum (since := "2024-10-17")]
+-- This is not in the `List` namespace as later `List.sum` will be defined polymorphically.
 protected def _root_.Nat.sum (l : List Nat) : Nat := l.foldr (·+·) 0
 
-set_option linter.deprecated false in
-@[simp, deprecated sum_nil (since := "2024-10-17")]
-theorem _root_.Nat.sum_nil : Nat.sum ([] : List Nat) = 0 := rfl
-set_option linter.deprecated false in
-@[simp, deprecated sum_cons (since := "2024-10-17")]
-theorem _root_.Nat.sum_cons (a : Nat) (l : List Nat) :
+@[simp] theorem _root_.Nat.sum_nil : Nat.sum ([] : List Nat) = 0 := rfl
+@[simp] theorem _root_.Nat.sum_cons (a : Nat) (l : List Nat) :
     Nat.sum (a::l) = a + Nat.sum l := rfl
 
 /-! ### range -/
@@ -1537,34 +1464,30 @@ def enum : List α → List (Nat × α) := enumFrom 0
 
 /-! ## Minima and maxima -/
 
-/-! ### min? -/
+/-! ### minimum? -/
 
 /--
 Returns the smallest element of the list, if it is not empty.
-* `[].min? = none`
-* `[4].min? = some 4`
-* `[1, 4, 2, 10, 6].min? = some 1`
+* `[].minimum? = none`
+* `[4].minimum? = some 4`
+* `[1, 4, 2, 10, 6].minimum? = some 1`
 -/
-def min? [Min α] : List α → Option α
+def minimum? [Min α] : List α → Option α
   | []    => none
   | a::as => some <| as.foldl min a
 
-@[inherit_doc min?, deprecated min? (since := "2024-09-29")] abbrev minimum? := @min?
-
-/-! ### max? -/
+/-! ### maximum? -/
 
 /--
 Returns the largest element of the list, if it is not empty.
-* `[].max? = none`
-* `[4].max? = some 4`
-* `[1, 4, 2, 10, 6].max? = some 10`
+* `[].maximum? = none`
+* `[4].maximum? = some 4`
+* `[1, 4, 2, 10, 6].maximum? = some 10`
 -/
-def max? [Max α] : List α → Option α
+def maximum? [Max α] : List α → Option α
   | []    => none
   | a::as => some <| as.foldl max a
 
-@[inherit_doc max?, deprecated max? (since := "2024-09-29")] abbrev maximum? := @max?
-
 /-! ## Other list operations
 
 The functions are currently mostly used in meta code,
@@ -1600,7 +1523,7 @@ def intersperse (sep : α) : List α → List α
 * `intercalate sep [a, b, c] = a ++ sep ++ b ++ sep ++ c`
 -/
 def intercalate (sep : List α) (xs : List (List α)) : List α :=
-  (intersperse sep xs).flatten
+  join (intersperse sep xs)
 
 /-! ### eraseDups -/
 
@@ -1652,23 +1575,23 @@ where
     | true  => loop as (a::rs)
     | false => (rs.reverse, a::as)
 
-/-! ### splitBy -/
+/-! ### groupBy -/
 
 /--
-`O(|l|)`. `splitBy R l` splits `l` into chains of elements
+`O(|l|)`. `groupBy R l` splits `l` into chains of elements
 such that adjacent elements are related by `R`.
 
-* `splitBy (·==·) [1, 1, 2, 2, 2, 3, 2] = [[1, 1], [2, 2, 2], [3], [2]]`
-* `splitBy (·<·) [1, 2, 5, 4, 5, 1, 4] = [[1, 2, 5], [4, 5], [1, 4]]`
+* `groupBy (·==·) [1, 1, 2, 2, 2, 3, 2] = [[1, 1], [2, 2, 2], [3], [2]]`
+* `groupBy (·<·) [1, 2, 5, 4, 5, 1, 4] = [[1, 2, 5], [4, 5], [1, 4]]`
 -/
-@[specialize] def splitBy (R : α → α → Bool) : List α → List (List α)
+@[specialize] def groupBy (R : α → α → Bool) : List α → List (List α)
   | []    => []
   | a::as => loop as a [] []
 where
   /--
-  The arguments of `splitBy.loop l ag g gs` represent the following:
+  The arguments of `groupBy.loop l ag g gs` represent the following:
 
-  - `l : List α` are the elements which we still need to split.
+  - `l : List α` are the elements which we still need to group.
   - `ag : α` is the previous element for which a comparison was performed.
   - `g : List α` is the group currently being assembled, in **reverse order**.
   - `gs : List (List α)` is all of the groups that have been completed, in **reverse order**.
@@ -1679,8 +1602,6 @@ where
     | false => loop as a [] ((ag::g).reverse::gs)
   | [], ag, g, gs => ((ag::g).reverse::gs).reverse
 
-@[deprecated splitBy (since := "2024-10-30"), inherit_doc splitBy] abbrev groupBy := @splitBy
-
 /-! ### removeAll -/
 
 /-- `O(|xs|)`. Computes the "set difference" of lists,

src/Init/Data/List/BasicAux.lean

@@ -155,8 +155,7 @@ def mapMono (as : List α) (f : α → α) : List α :=
 
 /-! ## Additional lemmas required for bootstrapping `Array`. -/
 
-theorem getElem_append_left {as bs : List α} (h : i < as.length) {h' : i < (as ++ bs).length} :
-    (as ++ bs)[i] = as[i] := by
+theorem getElem_append_left {as bs : List α} (h : i < as.length) {h'} : (as ++ bs)[i] = as[i] := by
   induction as generalizing i with
   | nil => trivial
   | cons a as ih =>
@@ -233,12 +232,11 @@ theorem sizeOf_get [SizeOf α] (as : List α) (i : Fin as.length) : sizeOf (as.g
     apply Nat.lt_trans ih
     simp_arith
 
-theorem le_antisymm [LT α] [s : Std.Antisymm (¬ · < · : α → α → Prop)]
-    {as bs : List α} (h₁ : as ≤ bs) (h₂ : bs ≤ as) : as = bs :=
+theorem le_antisymm [LT α] [s : Antisymm (¬ · < · : α → α → Prop)] {as bs : List α} (h₁ : as ≤ bs) (h₂ : bs ≤ as) : as = bs :=
   match as, bs with
   | [],    []    => rfl
-  | [],    _::_ => False.elim <| h₂ (List.lt.nil ..)
-  | _::_, []    => False.elim <| h₁ (List.lt.nil ..)
+  | [],    b::bs => False.elim <| h₂ (List.lt.nil ..)
+  | a::as, []    => False.elim <| h₁ (List.lt.nil ..)
   | a::as, b::bs => by
     by_cases hab : a < b
     · exact False.elim <| h₂ (List.lt.head _ _ hab)
@@ -250,8 +248,7 @@ theorem le_antisymm [LT α] [s : Std.Antisymm (¬ · < · : α → α → Prop)]
         have : a = b := s.antisymm hab hba
         simp [this, ih]
 
-instance [LT α] [Std.Antisymm (¬ · < · : α → α → Prop)] :
-    Std.Antisymm (· ≤ · : List α → List α → Prop) where
+instance [LT α] [Antisymm (¬ · < · : α → α → Prop)] : Antisymm (· ≤ · : List α → List α → Prop) where
   antisymm h₁ h₂ := le_antisymm h₁ h₂
 
 end List

src/Init/Data/List/Control.lean

@@ -5,8 +5,6 @@ Author: Leonardo de Moura
 -/
 prelude
 import Init.Control.Basic
-import Init.Control.Id
-import Init.Control.Lawful
 import Init.Data.List.Basic
 
 namespace List
@@ -209,16 +207,6 @@ def findM? {m : Type → Type u} [Monad m] {α : Type} (p : α → m Bool) : Lis
     | true  => pure (some a)
     | false => findM? p as
 
-@[simp]
-theorem findM?_id (p : α → Bool) (as : List α) : findM? (m := Id) p as = as.find? p := by
-  induction as with
-  | nil => rfl
-  | cons a as ih =>
-    simp only [findM?, find?]
-    cases p a with
-    | true  => rfl
-    | false => rw [ih]; rfl
-
 @[specialize]
 def findSomeM? {m : Type u → Type v} [Monad m] {α : Type w} {β : Type u} (f : α → m (Option β)) : List α → m (Option β)
   | []    => pure none
@@ -227,27 +215,26 @@ def findSomeM? {m : Type u → Type v} [Monad m] {α : Type w} {β : Type u} (f
     | some b => pure (some b)
     | none   => findSomeM? f as
 
-@[simp]
-theorem findSomeM?_id (f : α → Option β) (as : List α) : findSomeM? (m := Id) f as = as.findSome? f := by
-  induction as with
-  | nil => rfl
-  | cons a as ih =>
-    simp only [findSomeM?, findSome?]
-    cases f a with
-    | some b => rfl
-    | none   => rw [ih]; rfl
+@[inline] protected def forIn {α : Type u} {β : Type v} {m : Type v → Type w} [Monad m] (as : List α) (init : β) (f : α → β → m (ForInStep β)) : m β :=
+  let rec @[specialize] loop
+    | [], b    => pure b
+    | a::as, b => do
+      match (← f a b) with
+      | ForInStep.done b  => pure b
+      | ForInStep.yield b => loop as b
+  loop as init
 
-theorem findM?_eq_findSomeM? [Monad m] [LawfulMonad m] (p : α → m Bool) (as : List α) :
-    as.findM? p = as.findSomeM? fun a => return if (← p a) then some a else none := by
-  induction as with
-  | nil => rfl
-  | cons a as ih =>
-    simp only [findM?, findSomeM?]
-    simp [ih]
-    congr
-    apply funext
-    intro b
-    cases b <;> simp
+instance : ForIn m (List α) α where
+  forIn := List.forIn
+
+@[simp] theorem forIn_eq_forIn [Monad m] : @List.forIn α β m _ = forIn := rfl
+
+@[simp] theorem forIn_nil [Monad m] (f : α → β → m (ForInStep β)) (b : β) : forIn [] b f = pure b :=
+  rfl
+
+@[simp] theorem forIn_cons [Monad m] (f : α → β → m (ForInStep β)) (a : α) (as : List α) (b : β)
+    : forIn (a::as) b f = f a b >>= fun | ForInStep.done b => pure b | ForInStep.yield b => forIn as b f :=
+  rfl
 
 @[inline] protected def forIn' {α : Type u} {β : Type v} {m : Type v → Type w} [Monad m] (as : List α) (init : β) (f : (a : α) → a ∈ as → β → m (ForInStep β)) : m β :=
   let rec @[specialize] loop : (as' : List α) → (b : β) → Exists (fun bs => bs ++ as' = as) → m β
@@ -256,7 +243,7 @@ theorem findM?_eq_findSomeM? [Monad m] [LawfulMonad m] (p : α → m Bool) (as :
       have : a ∈ as := by
         have ⟨bs, h⟩ := h
         subst h
-        exact mem_append_right _ (Mem.head ..)
+        exact mem_append_of_mem_right _ (Mem.head ..)
       match (← f a this b) with
       | ForInStep.done b  => pure b
       | ForInStep.yield b =>
@@ -267,15 +254,14 @@ theorem findM?_eq_findSomeM? [Monad m] [LawfulMonad m] (p : α → m Bool) (as :
 instance : ForIn' m (List α) α inferInstance where
   forIn' := List.forIn'
 
--- No separate `ForIn` instance is required because it can be derived from `ForIn'`.
-
-@[simp] theorem forIn'_eq_forIn' [Monad m] : @List.forIn' α β m _ = forIn' := rfl
-
-@[simp] theorem forIn'_nil [Monad m] (f : (a : α) → a ∈ [] → β → m (ForInStep β)) (b : β) : forIn' [] b f = pure b :=
-  rfl
-
-@[simp] theorem forIn_nil [Monad m] (f : α → β → m (ForInStep β)) (b : β) : forIn [] b f = pure b :=
-  rfl
+@[simp] theorem forIn'_eq_forIn {α : Type u} {β : Type v} {m : Type v → Type w} [Monad m] (as : List α) (init : β) (f : α → β → m (ForInStep β)) : forIn' as init (fun a _ b => f a b) = forIn as init f := by
+  simp [forIn', forIn, List.forIn, List.forIn']
+  have : ∀ cs h, List.forIn'.loop cs (fun a _ b => f a b) as init h = List.forIn.loop f as init := by
+    intro cs h
+    induction as generalizing cs init with
+    | nil => intros; rfl
+    | cons a as ih => intros; simp [List.forIn.loop, List.forIn'.loop, ih]
+  apply this
 
 instance : ForM m (List α) α where
   forM := List.forM

src/Init/Data/List/Count.lean

@@ -153,19 +153,13 @@ theorem countP_filterMap (p : β → Bool) (f : α → Option β) (l : List α)
   simp only [length_filterMap_eq_countP]
   congr
   ext a
-  simp +contextual [Option.getD_eq_iff, Option.isSome_eq_isSome]
+  simp (config := { contextual := true }) [Option.getD_eq_iff]
 
-@[simp] theorem countP_flatten (l : List (List α)) :
-    countP p l.flatten = (l.map (countP p)).sum := by
-  simp only [countP_eq_length_filter, filter_flatten]
+@[simp] theorem countP_join (l : List (List α)) :
+    countP p l.join = Nat.sum (l.map (countP p)) := by
+  simp only [countP_eq_length_filter, filter_join]
   simp [countP_eq_length_filter']
 
-@[deprecated countP_flatten (since := "2024-10-14")] abbrev countP_join := @countP_flatten
-
-theorem countP_flatMap (p : β → Bool) (l : List α) (f : α → List β) :
-    countP p (l.flatMap f) = sum (map (countP p ∘ f) l) := by
-  rw [List.flatMap, countP_flatten, map_map]
-
 @[simp] theorem countP_reverse (l : List α) : countP p l.reverse = countP p l := by
   simp [countP_eq_length_filter, filter_reverse]
 
@@ -236,10 +230,8 @@ theorem count_singleton (a b : α) : count a [b] = if b == a then 1 else 0 := by
 @[simp] theorem count_append (a : α) : ∀ l₁ l₂, count a (l₁ ++ l₂) = count a l₁ + count a l₂ :=
   countP_append _
 
-theorem count_flatten (a : α) (l : List (List α)) : count a l.flatten = (l.map (count a)).sum := by
-  simp only [count_eq_countP, countP_flatten, count_eq_countP']
-
-@[deprecated count_flatten (since := "2024-10-14")] abbrev count_join := @count_flatten
+theorem count_join (a : α) (l : List (List α)) : count a l.join = Nat.sum (l.map (count a)) := by
+  simp only [count_eq_countP, countP_join, count_eq_countP']
 
 @[simp] theorem count_reverse (a : α) (l : List α) : count a l.reverse = count a l := by
   simp only [count_eq_countP, countP_eq_length_filter, filter_reverse, length_reverse]
@@ -319,7 +311,7 @@ theorem replicate_count_eq_of_count_eq_length {l : List α} (h : count a l = len
 theorem count_le_count_map [DecidableEq β] (l : List α) (f : α → β) (x : α) :
     count x l ≤ count (f x) (map f l) := by
   rw [count, count, countP_map]
-  apply countP_mono_left; simp +contextual
+  apply countP_mono_left; simp (config := { contextual := true })
 
 theorem count_filterMap {α} [BEq β] (b : β) (f : α → Option β) (l : List α) :
     count b (filterMap f l) = countP (fun a => f a == some b) l := by
@@ -330,9 +322,6 @@ theorem count_filterMap {α} [BEq β] (b : β) (f : α → Option β) (l : List
   · simp
   · simp
 
-theorem count_flatMap {α} [BEq β] (l : List α) (f : α → List β) (x : β) :
-    count x (l.flatMap f) = sum (map (count x ∘ f) l) := countP_flatMap _ _ _
-
 theorem count_erase (a b : α) :
     ∀ l : List α, count a (l.erase b) = count a l - if b == a then 1 else 0
   | [] => by simp

src/Init/Data/List/Erase.lean

@@ -52,9 +52,9 @@ theorem eraseP_of_forall_not {l : List α} (h : ∀ a, a ∈ l → ¬p a) : l.er
 theorem eraseP_ne_nil {xs : List α} {p : α → Bool} : xs.eraseP p ≠ [] ↔ xs ≠ [] ∧ ∀ x, p x → xs ≠ [x] := by
   simp
 
-theorem exists_of_eraseP : ∀ {l : List α} {a} (_ : a ∈ l) (_ : p a),
+theorem exists_of_eraseP : ∀ {l : List α} {a} (al : a ∈ l) (pa : p a),
     ∃ a l₁ l₂, (∀ b ∈ l₁, ¬p b) ∧ p a ∧ l = l₁ ++ a :: l₂ ∧ l.eraseP p = l₁ ++ l₂
-  | b :: l, _, al, pa =>
+  | b :: l, a, al, pa =>
     if pb : p b then
       ⟨b, [], l, forall_mem_nil _, pb, by simp [pb]⟩
     else
@@ -168,8 +168,8 @@ theorem eraseP_append_left {a : α} (pa : p a) :
 
 theorem eraseP_append_right :
     ∀ {l₁ : List α} l₂, (∀ b ∈ l₁, ¬p b) → eraseP p (l₁++l₂) = l₁ ++ l₂.eraseP p
-  | [],     _, _ => rfl
-  | _ :: _, _, h => by
+  | [],      l₂, _ => rfl
+  | x :: xs, l₂, h => by
     simp [(forall_mem_cons.1 h).1, eraseP_append_right _ (forall_mem_cons.1 h).2]
 
 theorem eraseP_append (l₁ l₂ : List α) :

src/Init/Data/List/FinRange.lean

@@ -1,48 +0,0 @@
-/-
-Copyright (c) 2024 François G. Dorais. All rights reserved.
-Released under Apache 2.0 license as described in the file LICENSE.
-Authors: François G. Dorais
--/
-prelude
-import Init.Data.List.OfFn
-
-namespace List
-
-/-- `finRange n` lists all elements of `Fin n` in order -/
-def finRange (n : Nat) : List (Fin n) := ofFn fun i => i
-
-@[simp] theorem length_finRange (n) : (List.finRange n).length = n := by
-  simp [List.finRange]
-
-@[simp] theorem getElem_finRange (i : Nat) (h : i < (List.finRange n).length) :
-    (finRange n)[i] = Fin.cast (length_finRange n) ⟨i, h⟩ := by
-  simp [List.finRange]
-
-@[simp] theorem finRange_zero : finRange 0 = [] := by simp [finRange, ofFn]
-
-theorem finRange_succ (n) : finRange (n+1) = 0 :: (finRange n).map Fin.succ := by
-  apply List.ext_getElem; simp; intro i; cases i <;> simp
-
-theorem finRange_succ_last (n) :
-    finRange (n+1) = (finRange n).map Fin.castSucc ++ [Fin.last n] := by
-  apply List.ext_getElem
-  · simp
-  · intros
-    simp only [List.finRange, List.getElem_ofFn, getElem_append, length_map, length_ofFn,
-      getElem_map, Fin.castSucc_mk, getElem_singleton]
-    split
-    · rfl
-    · next h => exact Fin.eq_last_of_not_lt h
-
-theorem finRange_reverse (n) : (finRange n).reverse = (finRange n).map Fin.rev := by
-  induction n with
-  | zero => simp
-  | succ n ih =>
-    conv => lhs; rw [finRange_succ_last]
-    conv => rhs; rw [finRange_succ]
-    rw [reverse_append, reverse_cons, reverse_nil, nil_append, singleton_append, ← map_reverse,
-      map_cons, ih, map_map, map_map]
-    congr; funext
-    simp [Fin.rev_succ]
-
-end List

src/Init/Data/List/Find.lean

@@ -10,8 +10,7 @@ import Init.Data.List.Sublist
 import Init.Data.List.Range
 
 /-!
-Lemmas about `List.findSome?`, `List.find?`, `List.findIdx`, `List.findIdx?`, `List.indexOf`,
-and `List.lookup`.
+# Lemmas about `List.findSome?`, `List.find?`, `List.findIdx`, `List.findIdx?`, and `List.indexOf`.
 -/
 
 namespace List
@@ -96,22 +95,22 @@ theorem findSome?_eq_some_iff {f : α → Option β} {l : List α} {b : β} :
     · simp only [Option.guard_eq_none] at h
       simp [ih, h]
 
-@[simp] theorem head?_filterMap (f : α → Option β) (l : List α) : (l.filterMap f).head? = l.findSome? f := by
+@[simp] theorem filterMap_head? (f : α → Option β) (l : List α) : (l.filterMap f).head? = l.findSome? f := by
   induction l with
   | nil => simp
   | cons x xs ih =>
     simp only [filterMap_cons, findSome?_cons]
     split <;> simp [*]
 
-@[simp] theorem head_filterMap (f : α → Option β) (l : List α) (h) :
-    (l.filterMap f).head h = (l.findSome? f).get (by simp_all [Option.isSome_iff_ne_none]) := by
+@[simp] theorem filterMap_head (f : α → Option β) (l : List α) (h) :
+    (l.filterMap f).head h = (l.findSome? f).get (by simp_all [Option.isSome_iff_ne_none])  := by
   simp [head_eq_iff_head?_eq_some]
 
-@[simp] theorem getLast?_filterMap (f : α → Option β) (l : List α) : (l.filterMap f).getLast? = l.reverse.findSome? f := by
+@[simp] theorem filterMap_getLast? (f : α → Option β) (l : List α) : (l.filterMap f).getLast? = l.reverse.findSome? f := by
   rw [getLast?_eq_head?_reverse]
   simp [← filterMap_reverse]
 
-@[simp] theorem getLast_filterMap (f : α → Option β) (l : List α) (h) :
+@[simp] theorem filterMap_getLast (f : α → Option β) (l : List α) (h) :
     (l.filterMap f).getLast h = (l.reverse.findSome? f).get (by simp_all [Option.isSome_iff_ne_none]) := by
   simp [getLast_eq_iff_getLast_eq_some]
 
@@ -133,14 +132,14 @@ theorem findSome?_append {l₁ l₂ : List α} : (l₁ ++ l₂).findSome? f = (l
     simp only [cons_append, findSome?]
     split <;> simp_all
 
-theorem head_flatten {L : List (List α)} (h : ∃ l, l ∈ L ∧ l ≠ []) :
-    (flatten L).head (by simpa using h) = (L.findSome? fun l => l.head?).get (by simpa using h) := by
-  simp [head_eq_iff_head?_eq_some, head?_flatten]
+theorem head_join {L : List (List α)} (h : ∃ l, l ∈ L ∧ l ≠ []) :
+    (join L).head (by simpa using h) = (L.findSome? fun l => l.head?).get (by simpa using h) := by
+  simp [head_eq_iff_head?_eq_some, head?_join]
 
-theorem getLast_flatten {L : List (List α)} (h : ∃ l, l ∈ L ∧ l ≠ []) :
-    (flatten L).getLast (by simpa using h) =
+theorem getLast_join {L : List (List α)} (h : ∃ l, l ∈ L ∧ l ≠ []) :
+    (join L).getLast (by simpa using h) =
       (L.reverse.findSome? fun l => l.getLast?).get (by simpa using h) := by
-  simp [getLast_eq_iff_getLast_eq_some, getLast?_flatten]
+  simp [getLast_eq_iff_getLast_eq_some, getLast?_join]
 
 theorem findSome?_replicate : findSome? f (replicate n a) = if n = 0 then none else f a := by
   cases n with
@@ -180,7 +179,7 @@ theorem IsPrefix.findSome?_eq_some {l₁ l₂ : List α} {f : α → Option β}
     List.findSome? f l₁ = some b → List.findSome? f l₂ = some b := by
   rw [IsPrefix] at h
   obtain ⟨t, rfl⟩ := h
-  simp +contextual [findSome?_append]
+  simp (config := {contextual := true}) [findSome?_append]
 
 theorem IsPrefix.findSome?_eq_none {l₁ l₂ : List α} {f : α → Option β} (h : l₁ <+: l₂) :
     List.findSome? f l₂ = none → List.findSome? f l₁ = none :=
@@ -207,8 +206,7 @@ theorem IsInfix.findSome?_eq_none {l₁ l₂ : List α} {f : α → Option β} (
 @[simp] theorem find?_eq_none : find? p l = none ↔ ∀ x ∈ l, ¬ p x := by
   induction l <;> simp [find?_cons]; split <;> simp [*]
 
-theorem find?_eq_some_iff_append :
-    xs.find? p = some b ↔ p b ∧ ∃ as bs, xs = as ++ b :: bs ∧ ∀ a ∈ as, !p a := by
+theorem find?_eq_some : xs.find? p = some b ↔ p b ∧ ∃ as bs, xs = as ++ b :: bs ∧ ∀ a ∈ as, !p a := by
   induction xs with
   | nil => simp
   | cons x xs ih =>
@@ -244,9 +242,6 @@ theorem find?_eq_some_iff_append :
           cases h₁
           simp
 
-@[deprecated find?_eq_some_iff_append (since := "2024-11-06")]
-abbrev find?_eq_some := @find?_eq_some_iff_append
-
 @[simp]
 theorem find?_cons_eq_some : (a :: xs).find? p = some b ↔ (p a ∧ a = b) ∨ (!p a ∧ xs.find? p = some b) := by
   rw [find?_cons]
@@ -292,18 +287,18 @@ theorem get_find?_mem (xs : List α) (p : α → Bool) (h) : (xs.find? p).get h
     · simp only [find?_cons]
       split <;> simp_all
 
-@[simp] theorem head?_filter (p : α → Bool) (l : List α) : (l.filter p).head? = l.find? p := by
-  rw [← filterMap_eq_filter, head?_filterMap, findSome?_guard]
+@[simp] theorem filter_head? (p : α → Bool) (l : List α) : (l.filter p).head? = l.find? p := by
+  rw [← filterMap_eq_filter, filterMap_head?, findSome?_guard]
 
-@[simp] theorem head_filter (p : α → Bool) (l : List α) (h) :
+@[simp] theorem filter_head (p : α → Bool) (l : List α) (h) :
     (l.filter p).head h = (l.find? p).get (by simp_all [Option.isSome_iff_ne_none]) := by
   simp [head_eq_iff_head?_eq_some]
 
-@[simp] theorem getLast?_filter (p : α → Bool) (l : List α) : (l.filter p).getLast? = l.reverse.find? p := by
+@[simp] theorem filter_getLast? (p : α → Bool) (l : List α) : (l.filter p).getLast? = l.reverse.find? p := by
   rw [getLast?_eq_head?_reverse]
   simp [← filter_reverse]
 
-@[simp] theorem getLast_filter (p : α → Bool) (l : List α) (h) :
+@[simp] theorem filter_getLast (p : α → Bool) (l : List α) (h) :
     (l.filter p).getLast h = (l.reverse.find? p).get (by simp_all [Option.isSome_iff_ne_none]) := by
   simp [getLast_eq_iff_getLast_eq_some]
 
@@ -331,35 +326,35 @@ theorem get_find?_mem (xs : List α) (p : α → Bool) (h) : (xs.find? p).get h
     simp only [cons_append, find?]
     by_cases h : p x <;> simp [h, ih]
 
-@[simp] theorem find?_flatten (xs : List (List α)) (p : α → Bool) :
-    xs.flatten.find? p = xs.findSome? (·.find? p) := by
+@[simp] theorem find?_join (xs : List (List α)) (p : α → Bool) :
+    xs.join.find? p = xs.findSome? (·.find? p) := by
   induction xs with
   | nil => simp
   | cons x xs ih =>
-    simp only [flatten_cons, find?_append, findSome?_cons, ih]
+    simp only [join_cons, find?_append, findSome?_cons, ih]
     split <;> simp [*]
 
-theorem find?_flatten_eq_none {xs : List (List α)} {p : α → Bool} :
-    xs.flatten.find? p = none ↔ ∀ ys ∈ xs, ∀ x ∈ ys, !p x := by
+theorem find?_join_eq_none {xs : List (List α)} {p : α → Bool} :
+    xs.join.find? p = none ↔ ∀ ys ∈ xs, ∀ x ∈ ys, !p x := by
   simp
 
 /--
-If `find? p` returns `some a` from `xs.flatten`, then `p a` holds, and
+If `find? p` returns `some a` from `xs.join`, then `p a` holds, and
 some list in `xs` contains `a`, and no earlier element of that list satisfies `p`.
 Moreover, no earlier list in `xs` has an element satisfying `p`.
 -/
-theorem find?_flatten_eq_some {xs : List (List α)} {p : α → Bool} {a : α} :
-    xs.flatten.find? p = some a ↔
+theorem find?_join_eq_some {xs : List (List α)} {p : α → Bool} {a : α} :
+    xs.join.find? p = some a ↔
       p a ∧ ∃ as ys zs bs, xs = as ++ (ys ++ a :: zs) :: bs ∧
         (∀ a ∈ as, ∀ x ∈ a, !p x) ∧ (∀ x ∈ ys, !p x) := by
-  rw [find?_eq_some_iff_append]
+  rw [find?_eq_some]
   constructor
   · rintro ⟨h, ⟨ys, zs, h₁, h₂⟩⟩
     refine ⟨h, ?_⟩
-    rw [flatten_eq_append_iff] at h₁
+    rw [join_eq_append_iff] at h₁
     obtain (⟨as, bs, rfl, rfl, h₁⟩ | ⟨as, bs, c, cs, ds, rfl, rfl, h₁⟩) := h₁
     · replace h₁ := h₁.symm
-      rw [flatten_eq_cons_iff] at h₁
+      rw [join_eq_cons_iff] at h₁
       obtain ⟨bs, cs, ds, rfl, h₁, rfl⟩ := h₁
       refine ⟨as ++ bs, [], cs, ds, by simp, ?_⟩
       simp
@@ -376,25 +371,21 @@ theorem find?_flatten_eq_some {xs : List (List α)} {p : α → Bool} {a : α} :
       · intro x m
         simpa using h₂ x (by simpa using .inr m)
   · rintro ⟨h, ⟨as, ys, zs, bs, rfl, h₁, h₂⟩⟩
-    refine ⟨h, as.flatten ++ ys, zs ++ bs.flatten, by simp, ?_⟩
+    refine ⟨h, as.join ++ ys, zs ++ bs.join, by simp, ?_⟩
     intro a m
     simp at m
     obtain ⟨l, ml, m⟩ | m := m
     · exact h₁ l ml a m
     · exact h₂ a m
 
-@[simp] theorem find?_flatMap (xs : List α) (f : α → List β) (p : β → Bool) :
-    (xs.flatMap f).find? p = xs.findSome? (fun x => (f x).find? p) := by
-  simp [flatMap_def, findSome?_map]; rfl
+@[simp] theorem find?_bind (xs : List α) (f : α → List β) (p : β → Bool) :
+    (xs.bind f).find? p = xs.findSome? (fun x => (f x).find? p) := by
+  simp [bind_def, findSome?_map]; rfl
 
-@[deprecated find?_flatMap (since := "2024-10-16")] abbrev find?_bind := @find?_flatMap
-
-theorem find?_flatMap_eq_none {xs : List α} {f : α → List β} {p : β → Bool} :
-    (xs.flatMap f).find? p = none ↔ ∀ x ∈ xs, ∀ y ∈ f x, !p y := by
+theorem find?_bind_eq_none {xs : List α} {f : α → List β} {p : β → Bool} :
+    (xs.bind f).find? p = none ↔ ∀ x ∈ xs, ∀ y ∈ f x, !p y := by
   simp
 
-@[deprecated find?_flatMap_eq_none (since := "2024-10-16")] abbrev find?_bind_eq_none := @find?_flatMap_eq_none
-
 theorem find?_replicate : find? p (replicate n a) = if n = 0 then none else if p a then some a else none := by
   cases n
   · simp
@@ -441,7 +432,7 @@ theorem IsPrefix.find?_eq_some {l₁ l₂ : List α} {p : α → Bool} (h : l₁
     List.find? p l₁ = some b → List.find? p l₂ = some b := by
   rw [IsPrefix] at h
   obtain ⟨t, rfl⟩ := h
-  simp +contextual [find?_append]
+  simp (config := {contextual := true}) [find?_append]
 
 theorem IsPrefix.find?_eq_none {l₁ l₂ : List α} {p : α → Bool} (h : l₁ <+: l₂) :
     List.find? p l₂ = none → List.find? p l₁ = none :=
@@ -567,7 +558,7 @@ theorem not_of_lt_findIdx {p : α → Bool} {xs : List α} {i : Nat} (h : i < xs
     | inr e =>
       have ipm := Nat.succ_pred_eq_of_pos e
       have ilt := Nat.le_trans ho (findIdx_le_length p)
-      simp +singlePass only [← ipm, getElem_cons_succ]
+      simp (config := { singlePass := true }) only [← ipm, getElem_cons_succ]
       rw [← ipm, Nat.succ_lt_succ_iff] at h
       simpa using ih h
 
@@ -600,14 +591,15 @@ theorem findIdx_eq {p : α → Bool} {xs : List α} {i : Nat} (h : i < xs.length
 
 theorem findIdx_append (p : α → Bool) (l₁ l₂ : List α) :
     (l₁ ++ l₂).findIdx p =
-      if l₁.findIdx p < l₁.length then l₁.findIdx p else l₂.findIdx p + l₁.length := by
+      if ∃ x, x ∈ l₁ ∧ p x = true then l₁.findIdx p else l₂.findIdx p + l₁.length := by
   induction l₁ with
   | nil => simp
   | cons x xs ih =>
     simp only [findIdx_cons, length_cons, cons_append]
     by_cases h : p x
     · simp [h]
-    · simp only [h, ih, cond_eq_if, Bool.false_eq_true, ↓reduceIte, add_one_lt_add_one_iff]
+    · simp only [h, ih, cond_eq_if, Bool.false_eq_true, ↓reduceIte, mem_cons, exists_eq_or_imp,
+        false_or]
       split <;> simp [Nat.add_assoc]
 
 theorem IsPrefix.findIdx_le {l₁ l₂ : List α} {p : α → Bool} (h : l₁ <+: l₂) :
@@ -794,15 +786,15 @@ theorem findIdx?_of_eq_none {xs : List α} {p : α → Bool} (w : xs.findIdx? p
   induction xs with simp
   | cons _ _ _ => split <;> simp_all [Option.map_or', Option.map_map]; rfl
 
-theorem findIdx?_flatten {l : List (List α)} {p : α → Bool} :
-    l.flatten.findIdx? p =
+theorem findIdx?_join {l : List (List α)} {p : α → Bool} :
+    l.join.findIdx? p =
       (l.findIdx? (·.any p)).map
-        fun i => ((l.take i).map List.length).sum +
+        fun i => Nat.sum ((l.take i).map List.length) +
           (l[i]?.map fun xs => xs.findIdx p).getD 0 := by
   induction l with
   | nil => simp
   | cons xs l ih =>
-    simp only [flatten, findIdx?_append, map_take, map_cons, findIdx?, any_eq_true, Nat.zero_add,
+    simp only [join, findIdx?_append, map_take, map_cons, findIdx?, any_eq_true, Nat.zero_add,
       findIdx?_succ]
     split
     · simp only [Option.map_some', take_zero, sum_nil, length_cons, zero_lt_succ,
@@ -984,13 +976,4 @@ theorem IsInfix.lookup_eq_none {l₁ l₂ : List (α × β)} (h : l₁ <:+: l₂
 
 end lookup
 
-/-! ### Deprecations -/
-
-@[deprecated head_flatten (since := "2024-10-14")] abbrev head_join := @head_flatten
-@[deprecated getLast_flatten (since := "2024-10-14")] abbrev getLast_join := @getLast_flatten
-@[deprecated find?_flatten (since := "2024-10-14")] abbrev find?_join := @find?_flatten
-@[deprecated find?_flatten_eq_none (since := "2024-10-14")] abbrev find?_join_eq_none := @find?_flatten_eq_none
-@[deprecated find?_flatten_eq_some (since := "2024-10-14")] abbrev find?_join_eq_some := @find?_flatten_eq_some
-@[deprecated findIdx?_flatten (since := "2024-10-14")] abbrev findIdx?_join := @findIdx?_flatten
-
 end List

src/Init/Data/List/Impl.lean

@@ -23,7 +23,7 @@ namespace List
 The following operations are already tail-recursive, and do not need `@[csimp]` replacements:
 `get`, `foldl`, `beq`, `isEqv`, `reverse`, `elem` (and hence `contains`), `drop`, `dropWhile`,
 `partition`, `isPrefixOf`, `isPrefixOf?`, `find?`, `findSome?`, `lookup`, `any` (and hence `or`),
-`all` (and hence `and`) , `range`, `eraseDups`, `eraseReps`, `span`, `splitBy`.
+`all` (and hence `and`) , `range`, `eraseDups`, `eraseReps`, `span`, `groupBy`.
 
 The following operations are still missing `@[csimp]` replacements:
 `concat`, `zipWithAll`.
@@ -31,14 +31,14 @@ The following operations are still missing `@[csimp]` replacements:
 The following operations are not recursive to begin with
 (or are defined in terms of recursive primitives):
 `isEmpty`, `isSuffixOf`, `isSuffixOf?`, `rotateLeft`, `rotateRight`, `insert`, `zip`, `enum`,
-`min?`, `max?`, and `removeAll`.
+`minimum?`, `maximum?`, and `removeAll`.
 
 The following operations were already given `@[csimp]` replacements in `Init/Data/List/Basic.lean`:
 `length`, `map`, `filter`, `replicate`, `leftPad`, `unzip`, `range'`, `iota`, `intersperse`.
 
 The following operations are given `@[csimp]` replacements below:
 `set`, `filterMap`, `foldr`, `append`, `bind`, `join`,
-`take`, `takeWhile`, `dropLast`, `replace`, `modify`, `insertIdx`, `erase`, `eraseIdx`, `zipWith`,
+`take`, `takeWhile`, `dropLast`, `replace`, `erase`, `eraseIdx`, `zipWith`,
 `enumFrom`, and `intercalate`.
 
 -/
@@ -91,31 +91,31 @@ The following operations are given `@[csimp]` replacements below:
 @[specialize] def foldrTR (f : α → β → β) (init : β) (l : List α) : β := l.toArray.foldr f init
 
 @[csimp] theorem foldr_eq_foldrTR : @foldr = @foldrTR := by
-  funext α β f init l; simp [foldrTR, ← Array.foldr_toList, -Array.size_toArray]
+  funext α β f init l; simp [foldrTR, Array.foldr_eq_foldr_toList, -Array.size_toArray]
 
-/-! ### flatMap  -/
+/-! ### bind  -/
 
-/-- Tail recursive version of `List.flatMap`. -/
-@[inline] def flatMapTR (as : List α) (f : α → List β) : List β := go as #[] where
-  /-- Auxiliary for `flatMap`: `flatMap.go f as = acc.toList ++ bind f as` -/
+/-- Tail recursive version of `List.bind`. -/
+@[inline] def bindTR (as : List α) (f : α → List β) : List β := go as #[] where
+  /-- Auxiliary for `bind`: `bind.go f as = acc.toList ++ bind f as` -/
   @[specialize] go : List α → Array β → List β
   | [], acc => acc.toList
   | x::xs, acc => go xs (acc ++ f x)
 
-@[csimp] theorem flatMap_eq_flatMapTR : @List.flatMap = @flatMapTR := by
+@[csimp] theorem bind_eq_bindTR : @List.bind = @bindTR := by
   funext α β as f
-  let rec go : ∀ as acc, flatMapTR.go f as acc = acc.toList ++ as.flatMap f
-    | [], acc => by simp [flatMapTR.go, flatMap]
-    | x::xs, acc => by simp [flatMapTR.go, flatMap, go xs]
+  let rec go : ∀ as acc, bindTR.go f as acc = acc.toList ++ as.bind f
+    | [], acc => by simp [bindTR.go, bind]
+    | x::xs, acc => by simp [bindTR.go, bind, go xs]
   exact (go as #[]).symm
 
-/-! ### flatten -/
+/-! ### join -/
 
-/-- Tail recursive version of `List.flatten`. -/
-@[inline] def flattenTR (l : List (List α)) : List α := flatMapTR l id
+/-- Tail recursive version of `List.join`. -/
+@[inline] def joinTR (l : List (List α)) : List α := bindTR l id
 
-@[csimp] theorem flatten_eq_flattenTR : @flatten = @flattenTR := by
-  funext α l; rw [← List.flatMap_id, List.flatMap_eq_flatMapTR]; rfl
+@[csimp] theorem join_eq_joinTR : @join = @joinTR := by
+  funext α l; rw [← List.bind_id, List.bind_eq_bindTR]; rfl
 
 /-! ## Sublists -/
 
@@ -197,41 +197,6 @@ The following operations are given `@[csimp]` replacements below:
     · simp [*]
     · intro h; rw [IH] <;> simp_all
 
-/-! ### modify -/
-
-/-- Tail-recursive version of `modify`. -/
-def modifyTR (f : α → α) (n : Nat) (l : List α) : List α := go l n #[] where
-  /-- Auxiliary for `modifyTR`: `modifyTR.go f l n acc = acc.toList ++ modify f n l`. -/
-  go : List α → Nat → Array α → List α
-  | [], _, acc => acc.toList
-  | a :: l, 0, acc => acc.toListAppend (f a :: l)
-  | a :: l, n+1, acc => go l n (acc.push a)
-
-theorem modifyTR_go_eq : ∀ l n, modifyTR.go f l n acc = acc.toList ++ modify f n l
-  | [], n => by cases n <;> simp [modifyTR.go, modify]
-  | a :: l, 0 => by simp [modifyTR.go, modify]
-  | a :: l, n+1 => by simp [modifyTR.go, modify, modifyTR_go_eq l]
-
-@[csimp] theorem modify_eq_modifyTR : @modify = @modifyTR := by
-  funext α f n l; simp [modifyTR, modifyTR_go_eq]
-
-/-! ### insertIdx -/
-
-/-- Tail-recursive version of `insertIdx`. -/
-@[inline] def insertIdxTR (n : Nat) (a : α) (l : List α) : List α := go n l #[] where
-  /-- Auxiliary for `insertIdxTR`: `insertIdxTR.go a n l acc = acc.toList ++ insertIdx n a l`. -/
-  go : Nat → List α → Array α → List α
-  | 0, l, acc => acc.toListAppend (a :: l)
-  | _, [], acc => acc.toList
-  | n+1, a :: l, acc => go n l (acc.push a)
-
-theorem insertIdxTR_go_eq : ∀ n l, insertIdxTR.go a n l acc = acc.toList ++ insertIdx n a l
-  | 0, l | _+1, [] => by simp [insertIdxTR.go, insertIdx]
-  | n+1, a :: l => by simp [insertIdxTR.go, insertIdx, insertIdxTR_go_eq n l]
-
-@[csimp] theorem insertIdx_eq_insertIdxTR : @insertIdx = @insertIdxTR := by
-  funext α f n l; simp [insertIdxTR, insertIdxTR_go_eq]
-
 /-! ### erase -/
 
 /-- Tail recursive version of `List.erase`. -/
@@ -331,7 +296,7 @@ def enumFromTR (n : Nat) (l : List α) : List (Nat × α) :=
     | a::as, n => by
       rw [← show _ + as.length = n + (a::as).length from Nat.succ_add .., foldr, go as]
       simp [enumFrom, f]
-  rw [← Array.foldr_toList]
+  rw [Array.foldr_eq_foldr_toList]
   simp [go]
 
 /-! ## Other list operations -/
@@ -357,7 +322,7 @@ where
   | [_] => simp
   | x::y::xs =>
     let rec go {acc x} : ∀ xs,
-      intercalateTR.go sep.toArray x xs acc = acc.toList ++ flatten (intersperse sep (x::xs))
+      intercalateTR.go sep.toArray x xs acc = acc.toList ++ join (intersperse sep (x::xs))
     | [] => by simp [intercalateTR.go]
     | _::_ => by simp [intercalateTR.go, go]
     simp [intersperse, go]

src/Init/Data/List/MapIdx.lean

@@ -1,409 +0,0 @@
-/-
-Copyright (c) 2024 Lean FRO. All rights reserved.
-Released under Apache 2.0 license as described in the file LICENSE.
-Authors: Kim Morrison, Mario Carneiro
--/
-
-prelude
-import Init.Data.Array.Lemmas
-import Init.Data.List.Nat.Range
-import Init.Data.List.OfFn
-import Init.Data.Fin.Lemmas
-import Init.Data.Option.Attach
-
-namespace List
-
-/-! ## Operations using indexes -/
-
-/-! ### mapIdx -/
-
-
-/--
-Given a list `as = [a₀, a₁, ...]` function `f : Fin as.length → α → β`, returns the list
-`[f 0 a₀, f 1 a₁, ...]`.
--/
-@[inline] def mapFinIdx (as : List α) (f : Fin as.length → α → β) : List β := go as #[] (by simp) where
-  /-- Auxiliary for `mapFinIdx`:
-  `mapFinIdx.go [a₀, a₁, ...] acc = acc.toList ++ [f 0 a₀, f 1 a₁, ...]` -/
-  @[specialize] go : (bs : List α) → (acc : Array β) → bs.length + acc.size = as.length → List β
-  | [], acc, h => acc.toList
-  | a :: as, acc, h =>
-    go as (acc.push (f ⟨acc.size, by simp at h; omega⟩ a)) (by simp at h ⊢; omega)
-
-/--
-Given a function `f : Nat → α → β` and `as : List α`, `as = [a₀, a₁, ...]`, returns the list
-`[f 0 a₀, f 1 a₁, ...]`.
--/
-@[inline] def mapIdx (f : Nat → α → β) (as : List α) : List β := go as #[] where
-  /-- Auxiliary for `mapIdx`:
-  `mapIdx.go [a₀, a₁, ...] acc = acc.toList ++ [f acc.size a₀, f (acc.size + 1) a₁, ...]` -/
-  @[specialize] go : List α → Array β → List β
-  | [], acc => acc.toList
-  | a :: as, acc => go as (acc.push (f acc.size a))
-
-/-! ### mapFinIdx -/
-
-@[simp]
-theorem mapFinIdx_nil {f : Fin 0 → α → β} : mapFinIdx [] f = [] :=
-  rfl
-
-@[simp] theorem length_mapFinIdx_go :
-    (mapFinIdx.go as f bs acc h).length = as.length := by
-  induction bs generalizing acc with
-  | nil => simpa using h
-  | cons _ _ ih => simp [mapFinIdx.go, ih]
-
-@[simp] theorem length_mapFinIdx {as : List α} {f : Fin as.length → α → β} :
-    (as.mapFinIdx f).length = as.length := by
-  simp [mapFinIdx, length_mapFinIdx_go]
-
-theorem getElem_mapFinIdx_go {as : List α} {f : Fin as.length → α → β} {i : Nat} {h} {w} :
-    (mapFinIdx.go as f bs acc h)[i] =
-      if w' : i < acc.size then acc[i] else f ⟨i, by simp at w; omega⟩ (bs[i - acc.size]'(by simp at w; omega)) := by
-  induction bs generalizing acc with
-  | nil =>
-    simp only [length_mapFinIdx_go, length_nil, Nat.zero_add] at w h
-    simp only [mapFinIdx.go, Array.getElem_toList]
-    rw [dif_pos]
-  | cons _ _ ih =>
-    simp [mapFinIdx.go]
-    rw [ih]
-    simp
-    split <;> rename_i h₁ <;> split <;> rename_i h₂
-    · rw [Array.getElem_push_lt]
-    · have h₃ : i = acc.size := by omega
-      subst h₃
-      simp
-    · omega
-    · have h₃ : i - acc.size = (i - (acc.size + 1)) + 1 := by omega
-      simp [h₃]
-
-@[simp] theorem getElem_mapFinIdx {as : List α} {f : Fin as.length → α → β} {i : Nat} {h} :
-    (as.mapFinIdx f)[i] = f ⟨i, by simp at h; omega⟩ (as[i]'(by simp at h; omega)) := by
-  simp [mapFinIdx, getElem_mapFinIdx_go]
-
-theorem mapFinIdx_eq_ofFn {as : List α} {f : Fin as.length → α → β} :
-    as.mapFinIdx f = List.ofFn fun i : Fin as.length => f i as[i] := by
-  apply ext_getElem <;> simp
-
-@[simp] theorem getElem?_mapFinIdx {l : List α} {f : Fin l.length → α → β} {i : Nat} :
-    (l.mapFinIdx f)[i]? = l[i]?.pbind fun x m => f ⟨i, by simp [getElem?_eq_some_iff] at m; exact m.1⟩ x := by
-  simp only [getElem?_def, length_mapFinIdx, getElem_mapFinIdx]
-  split <;> simp
-
-@[simp]
-theorem mapFinIdx_cons {l : List α} {a : α} {f : Fin (l.length + 1) → α → β} :
-    mapFinIdx (a :: l) f = f 0 a :: mapFinIdx l (fun i => f i.succ) := by
-  apply ext_getElem
-  · simp
-  · rintro (_|i) h₁ h₂ <;> simp
-
-theorem mapFinIdx_append {K L : List α} {f : Fin (K ++ L).length → α → β} :
-    (K ++ L).mapFinIdx f =
-      K.mapFinIdx (fun i => f (i.castLE (by simp))) ++ L.mapFinIdx (fun i => f ((i.natAdd K.length).cast (by simp))) := by
-  apply ext_getElem
-  · simp
-  · intro i h₁ h₂
-    rw [getElem_append]
-    simp only [getElem_mapFinIdx, length_mapFinIdx]
-    split <;> rename_i h
-    · rw [getElem_append_left]
-      congr
-    · simp only [Nat.not_lt] at h
-      rw [getElem_append_right h]
-      congr
-      simp
-      omega
-
-@[simp] theorem mapFinIdx_concat {l : List α} {e : α} {f : Fin (l ++ [e]).length → α → β}:
-    (l ++ [e]).mapFinIdx f = l.mapFinIdx (fun i => f (i.castLE (by simp))) ++ [f ⟨l.length, by simp⟩ e] := by
-  simp [mapFinIdx_append]
-  congr
-
-theorem mapFinIdx_singleton {a : α} {f : Fin 1 → α → β} :
-    [a].mapFinIdx f = [f ⟨0, by simp⟩ a] := by
-  simp
-
-theorem mapFinIdx_eq_enum_map {l : List α} {f : Fin l.length → α → β} :
-    l.mapFinIdx f = l.enum.attach.map
-      fun ⟨⟨i, x⟩, m⟩ =>
-        f ⟨i, by rw [mk_mem_enum_iff_getElem?, getElem?_eq_some_iff] at m; exact m.1⟩ x := by
-  apply ext_getElem <;> simp
-
-@[simp]
-theorem mapFinIdx_eq_nil_iff {l : List α} {f : Fin l.length → α → β} :
-    l.mapFinIdx f = [] ↔ l = [] := by
-  rw [mapFinIdx_eq_enum_map, map_eq_nil_iff, attach_eq_nil_iff, enum_eq_nil_iff]
-
-theorem mapFinIdx_ne_nil_iff {l : List α} {f : Fin l.length → α → β} :
-    l.mapFinIdx f ≠ [] ↔ l ≠ [] := by
-  simp
-
-theorem exists_of_mem_mapFinIdx {b : β} {l : List α} {f : Fin l.length → α → β}
-    (h : b ∈ l.mapFinIdx f) : ∃ (i : Fin l.length), f i l[i] = b := by
-  rw [mapFinIdx_eq_enum_map] at h
-  replace h := exists_of_mem_map h
-  simp only [mem_attach, true_and, Subtype.exists, Prod.exists, mk_mem_enum_iff_getElem?] at h
-  obtain ⟨i, b, h, rfl⟩ := h
-  rw [getElem?_eq_some_iff] at h
-  obtain ⟨h', rfl⟩ := h
-  exact ⟨⟨i, h'⟩, rfl⟩
-
-@[simp] theorem mem_mapFinIdx {b : β} {l : List α} {f : Fin l.length → α → β} :
-    b ∈ l.mapFinIdx f ↔ ∃ (i : Fin l.length), f i l[i] = b := by
-  constructor
-  · intro h
-    exact exists_of_mem_mapFinIdx h
-  · rintro ⟨i, h, rfl⟩
-    rw [mem_iff_getElem]
-    exact ⟨i, by simp⟩
-
-theorem mapFinIdx_eq_cons_iff {l : List α} {b : β} {f : Fin l.length → α → β} :
-    l.mapFinIdx f = b :: l₂ ↔
-      ∃ (a : α) (l₁ : List α) (h : l = a :: l₁),
-        f ⟨0, by simp [h]⟩ a = b ∧ l₁.mapFinIdx (fun i => f (i.succ.cast (by simp [h]))) = l₂ := by
-  cases l with
-  | nil => simp
-  | cons x l' =>
-    simp only [mapFinIdx_cons, cons.injEq, length_cons, Fin.zero_eta, Fin.cast_succ_eq,
-      exists_and_left]
-    constructor
-    · rintro ⟨rfl, rfl⟩
-      refine ⟨x, rfl, l', by simp⟩
-    · rintro ⟨a, ⟨rfl, h⟩, ⟨_, ⟨rfl, rfl⟩, h⟩⟩
-      exact ⟨rfl, h⟩
-
-theorem mapFinIdx_eq_cons_iff' {l : List α} {b : β} {f : Fin l.length → α → β} :
-    l.mapFinIdx f = b :: l₂ ↔
-      l.head?.pbind (fun x m => (f ⟨0, by cases l <;> simp_all⟩ x)) = some b ∧
-        l.tail?.attach.map (fun ⟨t, m⟩ => t.mapFinIdx fun i => f (i.succ.cast (by cases l <;> simp_all))) = some l₂ := by
-  cases l <;> simp
-
-theorem mapFinIdx_eq_iff {l : List α} {f : Fin l.length → α → β} :
-    l.mapFinIdx f = l' ↔ ∃ h : l'.length = l.length, ∀ (i : Nat) (h : i < l.length), l'[i] = f ⟨i, h⟩ l[i] := by
-  constructor
-  · rintro rfl
-    simp
-  · rintro ⟨h, w⟩
-    apply ext_getElem <;> simp_all
-
-theorem mapFinIdx_eq_mapFinIdx_iff {l : List α} {f g : Fin l.length → α → β} :
-    l.mapFinIdx f = l.mapFinIdx g ↔ ∀ (i : Fin l.length), f i l[i] = g i l[i] := by
-  rw [eq_comm, mapFinIdx_eq_iff]
-  simp [Fin.forall_iff]
-
-@[simp] theorem mapFinIdx_mapFinIdx {l : List α} {f : Fin l.length → α → β} {g : Fin _ → β → γ} :
-    (l.mapFinIdx f).mapFinIdx g = l.mapFinIdx (fun i => g (i.cast (by simp)) ∘ f i) := by
-  simp [mapFinIdx_eq_iff]
-
-theorem mapFinIdx_eq_replicate_iff {l : List α} {f : Fin l.length → α → β} {b : β} :
-    l.mapFinIdx f = replicate l.length b ↔ ∀ (i : Fin l.length), f i l[i] = b := by
-  simp [eq_replicate_iff, length_mapFinIdx, mem_mapFinIdx, forall_exists_index, true_and]
-
-@[simp] theorem mapFinIdx_reverse {l : List α} {f : Fin l.reverse.length → α → β} :
-    l.reverse.mapFinIdx f = (l.mapFinIdx (fun i => f ⟨l.length - 1 - i, by simp; omega⟩)).reverse := by
-  simp [mapFinIdx_eq_iff]
-  intro i h
-  congr
-  omega
-
-/-! ### mapIdx -/
-
-@[simp]
-theorem mapIdx_nil {f : Nat → α → β} : mapIdx f [] = [] :=
-  rfl
-
-theorem mapIdx_go_length {arr : Array β} :
-    length (mapIdx.go f l arr) = length l + arr.size := by
-  induction l generalizing arr with
-  | nil => simp only [mapIdx.go, length_nil, Nat.zero_add]
-  | cons _ _ ih =>
-    simp only [mapIdx.go, ih, Array.size_push, Nat.add_succ, length_cons, Nat.add_comm]
-
-theorem length_mapIdx_go : ∀ {l : List α} {arr : Array β},
-    (mapIdx.go f l arr).length = l.length + arr.size
-  | [], _ => by simp [mapIdx.go]
-  | a :: l, _ => by
-    simp only [mapIdx.go, length_cons]
-    rw [length_mapIdx_go]
-    simp
-    omega
-
-@[simp] theorem length_mapIdx {l : List α} : (l.mapIdx f).length = l.length := by
-  simp [mapIdx, length_mapIdx_go]
-
-theorem getElem?_mapIdx_go : ∀ {l : List α} {arr : Array β} {i : Nat},
-    (mapIdx.go f l arr)[i]? =
-      if h : i < arr.size then some arr[i] else Option.map (f i) l[i - arr.size]?
-  | [], arr, i => by
-    simp only [mapIdx.go, Array.toListImpl_eq, getElem?_def, Array.length_toList,
-      ← Array.getElem_toList, length_nil, Nat.not_lt_zero, ↓reduceDIte, Option.map_none']
-  | a :: l, arr, i => by
-    rw [mapIdx.go, getElem?_mapIdx_go]
-    simp only [Array.size_push]
-    split <;> split
-    · simp only [Option.some.injEq]
-      rw [← Array.getElem_toList]
-      simp only [Array.push_toList]
-      rw [getElem_append_left, ← Array.getElem_toList]
-    · have : i = arr.size := by omega
-      simp_all
-    · omega
-    · have : i - arr.size = i - (arr.size + 1) + 1 := by omega
-      simp_all
-
-@[simp] theorem getElem?_mapIdx {l : List α} {i : Nat} :
-    (l.mapIdx f)[i]? = Option.map (f i) l[i]? := by
-  simp [mapIdx, getElem?_mapIdx_go]
-
-@[simp] theorem getElem_mapIdx {l : List α} {f : Nat → α → β} {i : Nat} {h : i < (l.mapIdx f).length} :
-    (l.mapIdx f)[i] = f i (l[i]'(by simpa using h)) := by
-  apply Option.some_inj.mp
-  rw [← getElem?_eq_getElem, getElem?_mapIdx, getElem?_eq_getElem (by simpa using h)]
-  simp
-
-@[simp] theorem mapFinIdx_eq_mapIdx {l : List α} {f : Fin l.length → α → β} {g : Nat → α → β}
-    (h : ∀ (i : Fin l.length), f i l[i] = g i l[i]) :
-    l.mapFinIdx f = l.mapIdx g := by
-  simp_all [mapFinIdx_eq_iff]
-
-theorem mapIdx_eq_mapFinIdx {l : List α} {f : Nat → α → β} :
-    l.mapIdx f = l.mapFinIdx (fun i => f i) := by
-  simp [mapFinIdx_eq_mapIdx]
-
-theorem mapIdx_eq_enum_map {l : List α} :
-    l.mapIdx f = l.enum.map (Function.uncurry f) := by
-  ext1 i
-  simp only [getElem?_mapIdx, Option.map, getElem?_map, getElem?_enum]
-  split <;> simp
-
-@[simp]
-theorem mapIdx_cons {l : List α} {a : α} :
-    mapIdx f (a :: l) = f 0 a :: mapIdx (fun i => f (i + 1)) l := by
-  simp [mapIdx_eq_enum_map, enum_eq_zip_range, map_uncurry_zip_eq_zipWith,
-    range_succ_eq_map, zipWith_map_left]
-
-theorem mapIdx_append {K L : List α} :
-    (K ++ L).mapIdx f = K.mapIdx f ++ L.mapIdx fun i => f (i + K.length) := by
-  induction K generalizing f with
-  | nil => rfl
-  | cons _ _ ih => simp [ih (f := fun i => f (i + 1)), Nat.add_assoc]
-
-@[simp] theorem mapIdx_concat {l : List α} {e : α} :
-    mapIdx f (l ++ [e]) = mapIdx f l ++ [f l.length e] := by
-  simp [mapIdx_append]
-
-theorem mapIdx_singleton {a : α} : mapIdx f [a] = [f 0 a] := by
-  simp
-
-@[simp]
-theorem mapIdx_eq_nil_iff {l : List α} : List.mapIdx f l = [] ↔ l = [] := by
-  rw [List.mapIdx_eq_enum_map, List.map_eq_nil_iff, List.enum_eq_nil_iff]
-
-theorem mapIdx_ne_nil_iff {l : List α} :
-    List.mapIdx f l ≠ [] ↔ l ≠ [] := by
-  simp
-
-theorem exists_of_mem_mapIdx {b : β} {l : List α}
-    (h : b ∈ mapIdx f l) : ∃ (i : Nat) (h : i < l.length), f i l[i] = b := by
-  rw [mapIdx_eq_mapFinIdx] at h
-  simpa [Fin.exists_iff] using exists_of_mem_mapFinIdx h
-
-@[simp] theorem mem_mapIdx {b : β} {l : List α} :
-    b ∈ mapIdx f l ↔ ∃ (i : Nat) (h : i < l.length), f i l[i] = b := by
-  constructor
-  · intro h
-    exact exists_of_mem_mapIdx h
-  · rintro ⟨i, h, rfl⟩
-    rw [mem_iff_getElem]
-    exact ⟨i, by simpa using h, by simp⟩
-
-theorem mapIdx_eq_cons_iff {l : List α} {b : β} :
-    mapIdx f l = b :: l₂ ↔
-      ∃ (a : α) (l₁ : List α), l = a :: l₁ ∧ f 0 a = b ∧ mapIdx (fun i => f (i + 1)) l₁ = l₂ := by
-  cases l <;> simp [and_assoc]
-
-theorem mapIdx_eq_cons_iff' {l : List α} {b : β} :
-    mapIdx f l = b :: l₂ ↔
-      l.head?.map (f 0) = some b ∧ l.tail?.map (mapIdx fun i => f (i + 1)) = some l₂ := by
-  cases l <;> simp
-
-theorem mapIdx_eq_iff {l : List α} : mapIdx f l = l' ↔ ∀ i : Nat, l'[i]? = l[i]?.map (f i) := by
-  constructor
-  · intro w i
-    simpa using congrArg (fun l => l[i]?) w.symm
-  · intro w
-    ext1 i
-    simp [w]
-
-theorem mapIdx_eq_mapIdx_iff {l : List α} :
-    mapIdx f l = mapIdx g l ↔ ∀ i : Nat, (h : i < l.length) → f i l[i] = g i l[i] := by
-  constructor
-  · intro w i h
-    simpa [h] using congrArg (fun l => l[i]?) w
-  · intro w
-    apply ext_getElem
-    · simp
-    · intro i h₁ h₂
-      simp [w]
-
-@[simp] theorem mapIdx_set {l : List α} {i : Nat} {a : α} :
-    (l.set i a).mapIdx f = (l.mapIdx f).set i (f i a) := by
-  simp only [mapIdx_eq_iff, getElem?_set, length_mapIdx, getElem?_mapIdx]
-  intro i
-  split
-  · split <;> simp_all
-  · rfl
-
-@[simp] theorem head_mapIdx {l : List α} {f : Nat → α → β} {w : mapIdx f l ≠ []} :
-    (mapIdx f l).head w = f 0 (l.head (by simpa using w)) := by
-  cases l with
-  | nil => simp at w
-  | cons _ _ => simp
-
-@[simp] theorem head?_mapIdx {l : List α} {f : Nat → α → β} : (mapIdx f l).head? = l.head?.map (f 0) := by
-  cases l <;> simp
-
-@[simp] theorem getLast_mapIdx {l : List α} {f : Nat → α → β} {h} :
-    (mapIdx f l).getLast h = f (l.length - 1) (l.getLast (by simpa using h)) := by
-  cases l with
-  | nil => simp at h
-  | cons _ _ =>
-    simp only [← getElem_cons_length _ _ _ rfl]
-    simp only [mapIdx_cons]
-    simp only [← getElem_cons_length _ _ _ rfl]
-    simp only [← mapIdx_cons, getElem_mapIdx]
-    simp
-
-@[simp] theorem getLast?_mapIdx {l : List α} {f : Nat → α → β} :
-    (mapIdx f l).getLast? = (getLast? l).map (f (l.length - 1)) := by
-  cases l
-  · simp
-  · rw [getLast?_eq_getLast, getLast?_eq_getLast, getLast_mapIdx] <;> simp
-
-@[simp] theorem mapIdx_mapIdx {l : List α} {f : Nat → α → β} {g : Nat → β → γ} :
-    (l.mapIdx f).mapIdx g = l.mapIdx (fun i => g i ∘ f i) := by
-  simp [mapIdx_eq_iff]
-
-theorem mapIdx_eq_replicate_iff {l : List α} {f : Nat → α → β} {b : β} :
-    mapIdx f l = replicate l.length b ↔ ∀ (i : Nat) (h : i < l.length), f i l[i] = b := by
-  simp only [eq_replicate_iff, length_mapIdx, mem_mapIdx, forall_exists_index, true_and]
-  constructor
-  · intro w i h
-    apply w _ _ _ rfl
-  · rintro w _ i h rfl
-    exact w i h
-
-@[simp] theorem mapIdx_reverse {l : List α} {f : Nat → α → β} :
-    l.reverse.mapIdx f = (mapIdx (fun i => f (l.length - 1 - i)) l).reverse := by
-  simp [mapIdx_eq_iff]
-  intro i
-  by_cases h : i < l.length
-  · simp [getElem?_reverse, h]
-    congr
-    omega
-  · simp at h
-    rw [getElem?_eq_none (by simp [h]), getElem?_eq_none (by simp [h])]
-    simp
-
-end List