chore: code convention

.github/ISSUE_TEMPLATE/bug_report.md

@@ -9,15 +9,9 @@ assignees: ''
 
 ### Prerequisites
 
-Please put an X between the brackets as you perform the following steps:
-
-* [ ] Check that your issue is not already filed:
-      https://github.com/leanprover/lean4/issues
-* [ ] Reduce the issue to a minimal, self-contained, reproducible test case.
-      Avoid dependencies to Mathlib or Batteries.
-* [ ] Test your test case against the latest nightly release, for example on
-      https://live.lean-lang.org/#project=lean-nightly
-      (You can also use the settings there to switch to “Lean nightly”)
+* [ ] Put an X between the brackets on this line if you have done all of the following:
+    * Check that your issue is not already [filed](https://github.com/leanprover/lean4/issues).
+    * Reduce the issue to a minimal, self-contained, reproducible test case. Avoid dependencies to mathlib4 or std4.
 
 ### Description
 
@@ -25,7 +19,7 @@ Please put an X between the brackets as you perform the following steps:
 
 ### Context
 
-[Broader context that the issue occurred in. If there was any prior discussion on [the Lean Zulip](https://leanprover.zulipchat.com), link it here as well.]
+[Broader context that the issue occured in. If there was any prior discussion on [the Lean Zulip](https://leanprover.zulipchat.com), link it here as well.]
 
 ### Steps to Reproduce
 
@@ -39,8 +33,8 @@ Please put an X between the brackets as you perform the following steps:
 
 ### Versions
 
-[Output of `#eval Lean.versionString`]
-[OS version, if not using live.lean-lang.org.]
+[Output of `#eval Lean.versionString` or of `lean --version` in the folder that the issue occured in]
+[OS version]
 
 ### Additional Information
 

.github/PULL_REQUEST_TEMPLATE.md

@@ -5,7 +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.
-* 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.
 * Remove this section, up to and including the `---` before submitting.

.github/workflows/actionlint.yml

@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Checkout
-      uses: actions/checkout@v4
+      uses: actions/checkout@v3
     - name: actionlint
       uses: raven-actions/actionlint@v1
       with:

.github/workflows/ci.yml

@@ -6,20 +6,10 @@ on:
     tags:
       - '*'
   pull_request:
+    types: [opened, synchronize, reopened, labeled]
   merge_group:
   schedule:
     - cron: '0 7 * * *'  # 8AM CET/11PM PT
-  # for manual re-release of a nightly
-  workflow_dispatch:
-    inputs:
-      action:
-        description: 'Action'
-        required: true
-        default: 'release nightly'
-        type: choice
-        options:
-        - release nightly
-
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}-${{ github.event_name }}
@@ -31,10 +21,8 @@ jobs:
   configure:
     runs-on: ubuntu-latest
     outputs:
-      # 0: PRs without special label
-      # 1: PRs with `merge-ci` label, merge queue checks, master commits
-      # 2: PRs with `release-ci` label, releases (incl. nightlies)
-      check-level: ${{ steps.set-level.outputs.check-level }}
+      # Should we run only a quick CI? Yes on a pull request without the full-ci label
+      quick: ${{ steps.set-quick.outputs.quick }}
       # The build matrix, dynamically generated here
       matrix: ${{ steps.set-matrix.outputs.result }}
       # Should we make a nightly release? If so, this output contains the lean version string, else it is empty
@@ -51,12 +39,164 @@ jobs:
       RELEASE_TAG: ${{ steps.set-release.outputs.RELEASE_TAG }}
 
     steps:
+      - name: Run quick CI?
+        id: set-quick
+        env:
+          quick: ${{
+            github.event_name == 'pull_request' && !contains( github.event.pull_request.labels.*.name, 'full-ci')
+           }}
+        run: |
+          echo "quick=${{env.quick}}" >> "$GITHUB_OUTPUT"
+
+      - name: Configure build matrix
+        id: set-matrix
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const quick = ${{ steps.set-quick.outputs.quick }};
+            console.log(`quick: ${quick}`)
+            let matrix = [
+              {
+                // portable release build: use channel with older glibc (2.27)
+                "name": "Linux LLVM",
+                "os": "ubuntu-latest",
+                "release": false,
+                "quick": false,
+                "shell": "nix develop .#oldGlibc -c bash -euxo pipefail {0}",
+                "llvm-url": "https://github.com/leanprover/lean-llvm/releases/download/15.0.1/lean-llvm-x86_64-linux-gnu.tar.zst",
+                "prepare-llvm": "../script/prepare-llvm-linux.sh lean-llvm*",
+                "binary-check": "ldd -v",
+                // foreign code may be linked against more recent glibc
+                // reverse-ffi needs to be updated to link to LLVM libraries
+                "CTEST_OPTIONS": "-E 'foreign|leanlaketest_reverse-ffi'",
+                "CMAKE_OPTIONS": "-DLLVM=ON -DLLVM_CONFIG=${GITHUB_WORKSPACE}/build/llvm-host/bin/llvm-config"
+              },
+              {
+                "name": "Linux release",
+                "os": "ubuntu-latest",
+                "release": true,
+                "quick": true,
+                "shell": "nix develop .#oldGlibc -c bash -euxo pipefail {0}",
+                "llvm-url": "https://github.com/leanprover/lean-llvm/releases/download/15.0.1/lean-llvm-x86_64-linux-gnu.tar.zst",
+                "prepare-llvm": "../script/prepare-llvm-linux.sh lean-llvm*",
+                "binary-check": "ldd -v",
+                // foreign code may be linked against more recent glibc
+                "CTEST_OPTIONS": "-E 'foreign'"
+              },
+              {
+                "name": "Linux",
+                "os": "ubuntu-latest",
+                "check-stage3": true,
+                "test-speedcenter": true,
+                "quick": false,
+              },
+              {
+                "name": "Linux Debug",
+                "os": "ubuntu-latest",
+                "quick": false,
+                "CMAKE_OPTIONS": "-DCMAKE_BUILD_TYPE=Debug",
+                // exclude seriously slow tests
+                "CTEST_OPTIONS": "-E 'interactivetest|leanpkgtest|laketest|benchtest'"
+              },
+              // TODO: suddenly started failing in CI
+              /*{
+                "name": "Linux fsanitize",
+                "os": "ubuntu-latest",
+                "quick": false,
+                // turn off custom allocator & symbolic functions to make LSAN do its magic
+                "CMAKE_OPTIONS": "-DLEAN_EXTRA_CXX_FLAGS=-fsanitize=address,undefined -DLEANC_EXTRA_FLAGS='-fsanitize=address,undefined -fsanitize-link-c++-runtime' -DSMALL_ALLOCATOR=OFF -DBSYMBOLIC=OFF",
+                // exclude seriously slow/problematic tests (laketests crash)
+                "CTEST_OPTIONS": "-E 'interactivetest|leanpkgtest|laketest|benchtest'"
+              },*/
+              {
+                "name": "macOS",
+                "os": "macos-13",
+                "release": true,
+                "quick": false,
+                "shell": "bash -euxo pipefail {0}",
+                "llvm-url": "https://github.com/leanprover/lean-llvm/releases/download/15.0.1/lean-llvm-x86_64-apple-darwin.tar.zst",
+                "prepare-llvm": "../script/prepare-llvm-macos.sh lean-llvm*",
+                "binary-check": "otool -L",
+                "tar": "gtar" // https://github.com/actions/runner-images/issues/2619
+              },
+              {
+                "name": "macOS aarch64",
+                "os": "macos-13",
+                "release": true,
+                "quick": false,
+                "cross": true,
+                "cross_target": "aarch64-apple-darwin",
+                "shell": "bash -euxo pipefail {0}",
+                "CMAKE_OPTIONS": "-DUSE_GMP=OFF -DLEAN_INSTALL_SUFFIX=-darwin_aarch64",
+                "llvm-url": "https://github.com/leanprover/lean-llvm/releases/download/15.0.1/lean-llvm-aarch64-apple-darwin.tar.zst https://github.com/leanprover/lean-llvm/releases/download/15.0.1/lean-llvm-x86_64-apple-darwin.tar.zst",
+                "prepare-llvm": "../script/prepare-llvm-macos.sh lean-llvm-aarch64-* lean-llvm-x86_64-*",
+                "binary-check": "otool -L",
+                "tar": "gtar" // https://github.com/actions/runner-images/issues/2619
+              },
+              {
+                "name": "Windows",
+                "os": "windows-2022",
+                "release": true,
+                "quick": false,
+                "shell": "msys2 {0}",
+                "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",
+                "prepare-llvm": "../script/prepare-llvm-mingw.sh lean-llvm*",
+                "binary-check": "ldd"
+              },
+              {
+                "name": "Linux aarch64",
+                "os": "ubuntu-latest",
+                "CMAKE_OPTIONS": "-DUSE_GMP=OFF -DLEAN_INSTALL_SUFFIX=-linux_aarch64",
+                "release": true,
+                "quick": false,
+                "cross": true,
+                "cross_target": "aarch64-unknown-linux-gnu",
+                "shell": "nix develop .#oldGlibcAArch -c bash -euxo pipefail {0}",
+                "llvm-url": "https://github.com/leanprover/lean-llvm/releases/download/15.0.1/lean-llvm-x86_64-linux-gnu.tar.zst https://github.com/leanprover/lean-llvm/releases/download/15.0.1/lean-llvm-aarch64-linux-gnu.tar.zst",
+                "prepare-llvm": "../script/prepare-llvm-linux.sh lean-llvm-aarch64-* lean-llvm-x86_64-*"
+              },
+              {
+                "name": "Linux 32bit",
+                "os": "ubuntu-latest",
+                // Use 32bit on stage0 and stage1 to keep oleans compatible
+                "CMAKE_OPTIONS": "-DSTAGE0_USE_GMP=OFF -DSTAGE0_LEAN_EXTRA_CXX_FLAGS='-m32' -DSTAGE0_LEANC_OPTS='-m32' -DSTAGE0_MMAP=OFF -DUSE_GMP=OFF -DLEAN_EXTRA_CXX_FLAGS='-m32' -DLEANC_OPTS='-m32' -DMMAP=OFF -DLEAN_INSTALL_SUFFIX=-linux_x86",
+                "cmultilib": true,
+                "release": true,
+                "quick": false,
+                "cross": true,
+                "shell": "bash -euxo pipefail {0}"
+              },
+              {
+                "name": "Web Assembly",
+                "os": "ubuntu-latest",
+                // Build a native 32bit binary in stage0 and use it to compile the oleans and the wasm build
+                "CMAKE_OPTIONS": "-DCMAKE_C_COMPILER_WORKS=1 -DSTAGE0_USE_GMP=OFF -DSTAGE0_LEAN_EXTRA_CXX_FLAGS='-m32' -DSTAGE0_LEANC_OPTS='-m32' -DSTAGE0_CMAKE_CXX_COMPILER=clang++ -DSTAGE0_CMAKE_C_COMPILER=clang -DSTAGE0_CMAKE_EXECUTABLE_SUFFIX=\"\" -DUSE_GMP=OFF -DMMAP=OFF -DSTAGE0_MMAP=OFF -DCMAKE_AR=../emsdk/emsdk-main/upstream/emscripten/emar -DCMAKE_TOOLCHAIN_FILE=../emsdk/emsdk-main/upstream/emscripten/cmake/Modules/Platform/Emscripten.cmake -DLEAN_INSTALL_SUFFIX=-linux_wasm32",
+                "wasm": true,
+                "cmultilib": true,
+                "release": true,
+                "quick": false,
+                "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\""
+              }
+            ];
+            console.log(`matrix:\n${JSON.stringify(matrix, null, 2)}`)
+            if (quick) {
+              return matrix.filter((job) => job.quick)
+            } else {
+              return matrix
+            }
+
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v3
         # don't schedule nightlies on forks
-        if: github.event_name == 'schedule' && github.repository == 'leanprover/lean4' || inputs.action == 'release nightly'
+        if: github.event_name == 'schedule' && github.repository == 'leanprover/lean4'
       - name: Set Nightly
-        if: github.event_name == 'schedule' && github.repository == 'leanprover/lean4' || inputs.action == 'release nightly'
+        if: github.event_name == 'schedule' && github.repository == 'leanprover/lean4'
         id: set-nightly
         run: |
           if [[ -n '${{ secrets.PUSH_NIGHTLY_TOKEN }}' ]]; then
@@ -101,168 +241,6 @@ jobs:
             echo "Tag ${TAG_NAME} did not match SemVer regex."
           fi
 
-      - name: Set check level
-        id: set-level
-        # We do not use github.event.pull_request.labels.*.name here because
-        # re-running a run does not update that list, and we do want to be able to
-        # rerun the workflow run after setting the `release-ci`/`merge-ci` labels.
-        run: |
-          check_level=0
-
-          if [[ -n "${{ steps.set-nightly.outputs.nightly }}" || -n "${{ steps.set-release.outputs.RELEASE_TAG }}" ]]; then
-            check_level=2
-          elif [[ "${{ github.event_name }}" != "pull_request" ]]; then
-            check_level=1
-          else
-            labels="$(gh api repos/${{ github.repository_owner }}/${{ github.event.repository.name }}/pulls/${{ github.event.pull_request.number }} --jq '.labels')"
-            if echo "$labels" | grep -q "release-ci"; then
-              check_level=2
-            elif echo "$labels" | grep -q "merge-ci"; then
-              check_level=1
-            fi
-          fi
-
-          echo "check-level=$check_level" >> "$GITHUB_OUTPUT"
-        env:
-          GH_TOKEN: ${{ github.token }}
-
-      - name: Configure build matrix
-        id: set-matrix
-        uses: actions/github-script@v7
-        with:
-          script: |
-            const level = ${{ steps.set-level.outputs.check-level }};
-            console.log(`level: ${level}`);
-            // use large runners where available (original repo)
-            let large = ${{ github.repository == 'leanprover/lean4' }};
-            let matrix = [
-              {
-                // portable release build: use channel with older glibc (2.27)
-                "name": "Linux LLVM",
-                "os": "ubuntu-latest",
-                "release": false,
-                "check-level": 2,
-                "shell": "nix develop .#oldGlibc -c bash -euxo pipefail {0}",
-                "llvm-url": "https://github.com/leanprover/lean-llvm/releases/download/15.0.1/lean-llvm-x86_64-linux-gnu.tar.zst",
-                "prepare-llvm": "../script/prepare-llvm-linux.sh lean-llvm*",
-                "binary-check": "ldd -v",
-                // foreign code may be linked against more recent glibc
-                // reverse-ffi needs to be updated to link to LLVM libraries
-                "CTEST_OPTIONS": "-E 'foreign|leanlaketest_reverse-ffi'",
-                "CMAKE_OPTIONS": "-DLLVM=ON -DLLVM_CONFIG=${GITHUB_WORKSPACE}/build/llvm-host/bin/llvm-config"
-              },
-              {
-                "name": "Linux release",
-                "os": large ? "nscloud-ubuntu-22.04-amd64-4x8" : "ubuntu-latest",
-                "release": true,
-                "check-level": 0,
-                "shell": "nix develop .#oldGlibc -c bash -euxo pipefail {0}",
-                "llvm-url": "https://github.com/leanprover/lean-llvm/releases/download/15.0.1/lean-llvm-x86_64-linux-gnu.tar.zst",
-                "prepare-llvm": "../script/prepare-llvm-linux.sh lean-llvm*",
-                "binary-check": "ldd -v",
-                // foreign code may be linked against more recent glibc
-                "CTEST_OPTIONS": "-E 'foreign'"
-              },
-              {
-                "name": "Linux",
-                "os": large ? "nscloud-ubuntu-22.04-amd64-4x8" : "ubuntu-latest",
-                "check-stage3": level >= 2,
-                "test-speedcenter": level >= 2,
-                "check-level": 1,
-              },
-              {
-                "name": "Linux Debug",
-                "os": "ubuntu-latest",
-                "check-level": 2,
-                "CMAKE_PRESET": "debug",
-                // exclude seriously slow tests
-                "CTEST_OPTIONS": "-E 'interactivetest|leanpkgtest|laketest|benchtest|bv_bitblast_stress'"
-              },
-              // TODO: suddenly started failing in CI
-              /*{
-                "name": "Linux fsanitize",
-                "os": "ubuntu-latest",
-                "check-level": 2,
-                // turn off custom allocator & symbolic functions to make LSAN do its magic
-                "CMAKE_PRESET": "sanitize",
-                // exclude seriously slow/problematic tests (laketests crash)
-                "CTEST_OPTIONS": "-E 'interactivetest|leanpkgtest|laketest|benchtest'"
-              },*/
-              {
-                "name": "macOS",
-                "os": "macos-13",
-                "release": true,
-                "check-level": 2,
-                "shell": "bash -euxo pipefail {0}",
-                "llvm-url": "https://github.com/leanprover/lean-llvm/releases/download/15.0.1/lean-llvm-x86_64-apple-darwin.tar.zst",
-                "prepare-llvm": "../script/prepare-llvm-macos.sh lean-llvm*",
-                "binary-check": "otool -L",
-                "tar": "gtar" // https://github.com/actions/runner-images/issues/2619
-              },
-              {
-                "name": "macOS aarch64",
-                "os": "macos-14",
-                "CMAKE_OPTIONS": "-DLEAN_INSTALL_SUFFIX=-darwin_aarch64",
-                "release": true,
-                "check-level": 0,
-                "shell": "bash -euxo pipefail {0}",
-                "llvm-url": "https://github.com/leanprover/lean-llvm/releases/download/15.0.1/lean-llvm-aarch64-apple-darwin.tar.zst",
-                "prepare-llvm": "../script/prepare-llvm-macos.sh lean-llvm*",
-                "binary-check": "otool -L",
-                "tar": "gtar" // https://github.com/actions/runner-images/issues/2619
-              },
-              {
-                "name": "Windows",
-                "os": "windows-2022",
-                "release": true,
-                "check-level": 2,
-                "shell": "msys2 {0}",
-                "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",
-                "prepare-llvm": "../script/prepare-llvm-mingw.sh lean-llvm*",
-                "binary-check": "ldd"
-              },
-              {
-                "name": "Linux aarch64",
-                "os": "nscloud-ubuntu-22.04-arm64-4x8",
-                "CMAKE_OPTIONS": "-DUSE_GMP=OFF -DLEAN_INSTALL_SUFFIX=-linux_aarch64",
-                "release": true,
-                "check-level": 2,
-                "shell": "nix develop .#oldGlibcAArch -c bash -euxo pipefail {0}",
-                "llvm-url": "https://github.com/leanprover/lean-llvm/releases/download/15.0.1/lean-llvm-aarch64-linux-gnu.tar.zst",
-                "prepare-llvm": "../script/prepare-llvm-linux.sh lean-llvm*"
-              },
-              {
-                "name": "Linux 32bit",
-                "os": "ubuntu-latest",
-                // Use 32bit on stage0 and stage1 to keep oleans compatible
-                "CMAKE_OPTIONS": "-DSTAGE0_USE_GMP=OFF -DSTAGE0_LEAN_EXTRA_CXX_FLAGS='-m32' -DSTAGE0_LEANC_OPTS='-m32' -DSTAGE0_MMAP=OFF -DUSE_GMP=OFF -DLEAN_EXTRA_CXX_FLAGS='-m32' -DLEANC_OPTS='-m32' -DMMAP=OFF -DLEAN_INSTALL_SUFFIX=-linux_x86 -DCMAKE_LIBRARY_PATH=/usr/lib/i386-linux-gnu/ -DSTAGE0_CMAKE_LIBRARY_PATH=/usr/lib/i386-linux-gnu/",
-                "cmultilib": true,
-                "release": true,
-                "check-level": 2,
-                "cross": true,
-                "shell": "bash -euxo pipefail {0}"
-              },
-              {
-                "name": "Web Assembly",
-                "os": "ubuntu-latest",
-                // Build a native 32bit binary in stage0 and use it to compile the oleans and the wasm build
-                "CMAKE_OPTIONS": "-DCMAKE_C_COMPILER_WORKS=1 -DSTAGE0_USE_GMP=OFF -DSTAGE0_LEAN_EXTRA_CXX_FLAGS='-m32' -DSTAGE0_LEANC_OPTS='-m32' -DSTAGE0_CMAKE_CXX_COMPILER=clang++ -DSTAGE0_CMAKE_C_COMPILER=clang -DSTAGE0_CMAKE_EXECUTABLE_SUFFIX=\"\" -DUSE_GMP=OFF -DMMAP=OFF -DSTAGE0_MMAP=OFF -DCMAKE_AR=../emsdk/emsdk-main/upstream/emscripten/emar -DCMAKE_TOOLCHAIN_FILE=../emsdk/emsdk-main/upstream/emscripten/cmake/Modules/Platform/Emscripten.cmake -DLEAN_INSTALL_SUFFIX=-linux_wasm32 -DSTAGE0_CMAKE_LIBRARY_PATH=/usr/lib/i386-linux-gnu/",
-                "wasm": true,
-                "cmultilib": true,
-                "release": true,
-                "check-level": 2,
-                "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_libuv\\.lean\""
-              }
-            ];
-            console.log(`matrix:\n${JSON.stringify(matrix, null, 2)}`)
-            return matrix.filter((job) => level >= job["check-level"])
-
   build:
     needs: [configure]
     if: github.event_name != 'schedule' || github.repository == 'leanprover/lean4'
@@ -289,34 +267,28 @@ jobs:
       CXX: c++
       MACOSX_DEPLOYMENT_TARGET: 10.15
     steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+        with:
+          submodules: true
+          # 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 }}
       - name: Install Nix
-        uses: DeterminateSystems/nix-installer-action@main
+        uses: cachix/install-nix-action@v18
+        with:
+          install_url: https://releases.nixos.org/nix/nix-2.12.0/install
         if: runner.os == 'Linux' && !matrix.cmultilib
       - name: Install MSYS2
         uses: msys2/setup-msys2@v2
         with:
           msystem: clang64
-          # `:` means do not prefix with msystem
-          pacboy: "make: python: cmake clang ccache gmp libuv git: zip: unzip: diffutils: binutils: tree: zstd tar:"
+          # `:p` means prefix with appropriate msystem prefix
+          pacboy: "make python cmake:p clang:p ccache:p gmp:p git zip unzip diffutils binutils tree zstd:p tar"
         if: runner.os == 'Windows'
       - name: Install Brew Packages
         run: |
-          brew install ccache tree zstd coreutils gmp libuv
+          brew install ccache tree zstd coreutils gmp
         if: runner.os == 'macOS'
-      - name: Checkout
-        uses: actions/checkout@v4
-        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 }}
-      # Do check out some CI-relevant files from virtual merge commit to accommodate CI changes on
-      # master (as the workflow files themselves are always taken from the merge)
-      # (needs to be after "Install *" to use the right shell)
-      - name: CI Merge Checkout
-        run: |
-          git fetch --depth=1 origin ${{ github.sha }}
-          git checkout FETCH_HEAD flake.nix flake.lock
-        if: github.event_name == 'pull_request'
-      # (needs to be after "Checkout" so files don't get overridden)
       - name: Setup emsdk
         uses: mymindstorm/setup-emsdk@v12
         with:
@@ -325,31 +297,33 @@ jobs:
         if: matrix.wasm
       - name: Install 32bit c libs
         run: |
-          sudo dpkg --add-architecture i386
           sudo apt-get update
-          sudo apt-get install -y gcc-multilib g++-multilib ccache libuv1-dev:i386
+          sudo apt-get install -y gcc-multilib g++-multilib ccache
         if: matrix.cmultilib
       - name: Cache
-        uses: actions/cache@v4
+        uses: actions/cache@v3
         with:
           path: .ccache
-          key: ${{ matrix.name }}-build-v3-${{ github.event.pull_request.head.sha }}
+          key: ${{ matrix.name }}-build-v3-${{ github.sha }}
           # fall back to (latest) previous cache
           restore-keys: |
             ${{ matrix.name }}-build-v3
-          save-always: true
-      # open nix-shell once for initial setup
       - name: Setup
         run: |
-          ccache --zero-stats
+          # open nix-shell once for initial setup
+          true
         if: runner.os == 'Linux'
-      - name: Set up NPROC
+      - name: Set up core dumps
         run: |
-          echo "NPROC=$(nproc 2>/dev/null || sysctl -n hw.logicalcpu 2>/dev/null || echo 4)" >> $GITHUB_ENV
+          mkdir -p $PWD/coredumps
+          # store in current directory, for easy uploading together with binary
+          echo $PWD/coredumps/%e.%p.%t | sudo tee /proc/sys/kernel/core_pattern
+        if: runner.os == 'Linux'
       - name: Build
         run: |
           mkdir build
           cd build
+          ulimit -c unlimited # coredumps
           # arguments passed to `cmake`
           # this also enables githash embedding into stage 1 library
           OPTIONS=(-DCHECK_OLEAN_VERSION=ON)
@@ -375,19 +349,11 @@ jobs:
             OPTIONS+=(-DLEAN_SPECIAL_VERSION_DESC=${{ needs.configure.outputs.LEAN_SPECIAL_VERSION_DESC }})
           fi
           # contortion to support empty OPTIONS with old macOS bash
-          cmake .. --preset ${{ matrix.CMAKE_PRESET || 'release' }} -B . ${{ matrix.CMAKE_OPTIONS }} ${OPTIONS[@]+"${OPTIONS[@]}"} -DLEAN_INSTALL_PREFIX=$PWD/..
-          time make -j$NPROC
-      - name: Install
-        run: |
-          make -C build install
+          cmake .. ${{ matrix.CMAKE_OPTIONS }} ${OPTIONS[@]+"${OPTIONS[@]}"} -DLEAN_INSTALL_PREFIX=$PWD/..
+          make -j4
+          make install
       - name: Check Binaries
         run: ${{ matrix.binary-check }} lean-*/bin/* || true
-      - name: Count binary symbols
-        run: |
-          for f in lean-*/bin/*; do
-            echo "$f: $(nm $f | grep " T " | wc -l) exported symbols"
-          done
-        if: matrix.name == 'Windows'
       - name: List Install Tree
         run: |
           # omit contents of Init/, ...
@@ -403,7 +369,7 @@ jobs:
           else
             ${{ matrix.tar || 'tar' }} cf - $dir | zstd -T0 --no-progress -o pack/$dir.tar.zst
           fi
-      - uses: actions/upload-artifact@v4
+      - uses: actions/upload-artifact@v3
         if: matrix.release
         with:
           name: build-${{ matrix.name }}
@@ -413,43 +379,71 @@ jobs:
           build/stage1/bin/lean --stats src/Lean.lean
         if: ${{ !matrix.cross }}
       - name: Test
-        id: test
         run: |
-          time ctest --preset ${{ matrix.CMAKE_PRESET || 'release' }} --test-dir build/stage1 -j$NPROC --output-junit test-results.xml ${{ matrix.CTEST_OPTIONS }}
-        if: (matrix.wasm || !matrix.cross) && needs.configure.outputs.check-level >= 1
+          cd build/stage1
+          ulimit -c unlimited # coredumps
+          # exclude nonreproducible test
+          ctest -j4 --progress --output-junit test-results.xml --output-on-failure ${{ matrix.CTEST_OPTIONS }} < /dev/null
+        if: (matrix.wasm || !matrix.cross) && needs.configure.outputs.quick == 'false'
       - name: Test Summary
         uses: test-summary/action@v2
         with:
           paths: build/stage1/test-results.xml
         # prefix `if` above with `always` so it's run even if tests failed
-        if: always() && steps.test.conclusion != 'skipped'
+        if: always() && (matrix.wasm || !matrix.cross) && needs.configure.outputs.quick == 'false'
       - name: Check Test Binary
         run: ${{ matrix.binary-check }} tests/compiler/534.lean.out
-        if: (!matrix.cross) && steps.test.conclusion != 'skipped'
+        if: ${{ !matrix.cross && needs.configure.outputs.quick == 'false' }}
       - name: Build Stage 2
         run: |
-          make -C build -j$NPROC stage2
+          cd build
+          ulimit -c unlimited # coredumps
+          make -j4 stage2
         if: matrix.test-speedcenter
       - name: Check Stage 3
         run: |
-          make -C build -j$NPROC check-stage3
+          cd build
+          ulimit -c unlimited # coredumps
+          make -j4 check-stage3
         if: matrix.test-speedcenter
       - name: Test Speedcenter Benchmarks
         run: |
-          # Necessary for some timing metrics but does not work on Namespace runners
-          # and we just want to test that the benchmarks run at all here
-          #echo -1 | sudo tee /proc/sys/kernel/perf_event_paranoid
+          echo -1 | sudo tee /proc/sys/kernel/perf_event_paranoid
           export BUILD=$PWD/build PATH=$PWD/build/stage1/bin:$PATH
           cd tests/bench
           nix shell .#temci -c temci exec --config speedcenter.yaml --included_blocks fast --runs 1
         if: matrix.test-speedcenter
       - name: Check rebootstrap
         run: |
+          cd build
+          ulimit -c unlimited # coredumps
           # clean rebuild in case of Makefile changes
-          make -C build update-stage0 && rm -rf build/stage* && make -C build -j$NPROC
-        if: matrix.name == 'Linux' && needs.configure.outputs.check-level >= 1
+          make update-stage0 && rm -rf ./stage* && make -j4
+        if: matrix.name == 'Linux' && needs.configure.outputs.quick == 'false'
       - name: CCache stats
         run: ccache -s
+      - name: Show stacktrace for coredumps
+        if: ${{ failure() && runner.os == 'Linux' }}
+        run: |
+          for c in coredumps/*; do
+            progbin="$(file $c | sed "s/.*execfn: '\([^']*\)'.*/\1/")"
+            echo bt | $GDB/bin/gdb -q $progbin $c || true
+          done
+      # has not been used in a long while, would need to be adapted to new
+      # shared libs
+      #- name: Upload coredumps
+      #  uses: actions/upload-artifact@v3
+      #  if: ${{ failure() && runner.os == 'Linux' }}
+      #  with:
+      #    name: coredumps-${{ matrix.name }}
+      #    path: |
+      #      ./coredumps
+      #      ./build/stage0/bin/lean
+      #      ./build/stage0/lib/lean/libleanshared.so
+      #      ./build/stage1/bin/lean
+      #      ./build/stage1/lib/lean/libleanshared.so
+      #      ./build/stage2/bin/lean
+      #      ./build/stage2/lib/lean/libleanshared.so
 
   # This job collects results from all the matrix jobs
   # This can be made the “required” job, instead of listing each
@@ -461,24 +455,12 @@ jobs:
     # mark as merely cancelled not failed if builds are cancelled
     if: ${{ !cancelled() }}
     steps:
-    - if: ${{ contains(needs.*.result, 'failure') && github.repository == 'leanprover/lean4' && github.ref_name == 'master' }}
-      uses: zulip/github-actions-zulip/send-message@v1
-      with:
-        api-key: ${{ secrets.ZULIP_BOT_KEY }}
-        email: "github-actions-bot@lean-fro.zulipchat.com"
-        organization-url: "https://lean-fro.zulipchat.com"
-        to: "infrastructure"
-        topic: "Github actions"
-        type: "stream"
-        content: |
-          A build of `${{ github.ref_name }}`, triggered by event `${{ github.event_name }}`, [failed](https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}).
     - if: contains(needs.*.result, 'failure')
       uses: actions/github-script@v7
       with:
         script: |
             core.setFailed('Some jobs failed')
 
-
   # This job creates releases from tags
   # (whether they are "unofficial" releases for experiments, or official releases when the tag is "v" followed by a semver string.)
   # We do not attempt to automatically construct a changelog here:
@@ -488,7 +470,7 @@ jobs:
     runs-on: ubuntu-latest
     needs: build
     steps:
-      - uses: actions/download-artifact@v4
+      - uses: actions/download-artifact@v3
         with:
           path: artifacts
       - name: Release
@@ -496,14 +478,8 @@ jobs:
         with:
           files: artifacts/*/*
           fail_on_unmatched_files: true
-          prerelease: ${{ !startsWith(github.ref, 'refs/tags/v') || contains(github.ref, '-rc') }}
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-      - name: Update release.lean-lang.org
-        run: |
-          gh workflow -R leanprover/release-index run update-index.yml
-        env:
-          GITHUB_TOKEN: ${{ secrets.RELEASE_INDEX_TOKEN }}
 
   # This job creates nightly releases during the cron job.
   # It is responsible for creating the tag, and automatically generating a changelog.
@@ -513,12 +489,12 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v3
         with:
           # needed for tagging
           fetch-depth: 0
           token: ${{ secrets.PUSH_NIGHTLY_TOKEN }}
-      - uses: actions/download-artifact@v4
+      - uses: actions/download-artifact@v3
         with:
           path: artifacts
       - name: Prepare Nightly Release
@@ -546,13 +522,3 @@ jobs:
           repository: ${{ github.repository_owner }}/lean4-nightly
         env:
           GITHUB_TOKEN: ${{ secrets.PUSH_NIGHTLY_TOKEN }}
-      - name: Update release.lean-lang.org
-        run: |
-          gh workflow -R leanprover/release-index run update-index.yml
-        env:
-          GITHUB_TOKEN: ${{ secrets.RELEASE_INDEX_TOKEN }}
-      - name: Update toolchain on mathlib4's nightly-testing branch
-        run: |
-          gh workflow -R leanprover-community/mathlib4 run nightly_bump_toolchain.yml
-        env:
-          GITHUB_TOKEN: ${{ secrets.MATHLIB4_BOT }}

.github/workflows/jira.yml

@@ -1,34 +0,0 @@
-name: Jira sync
-
-on:
-  issues:
-    types: [closed]
-
-jobs:
-  jira-sync:
-    runs-on: ubuntu-latest
-
-    steps:
-      - name: Move Jira issue to Done
-        env:
-          JIRA_API_TOKEN: ${{ secrets.JIRA_API_TOKEN }}
-          JIRA_USERNAME: ${{ secrets.JIRA_USERNAME }}
-          JIRA_BASE_URL: ${{ secrets.JIRA_BASE_URL }}
-        run: |
-          issue_number=${{ github.event.issue.number }}
-
-          jira_issue_key=$(curl -s -u "${JIRA_USERNAME}:${JIRA_API_TOKEN}" \
-            -X GET -H "Content-Type: application/json" \
-            "${JIRA_BASE_URL}/rest/api/2/search?jql=summary~\"${issue_number}\"" | \
-            jq -r '.issues[0].key')
-
-          if [ -z "$jira_issue_key" ]; then
-            exit
-          fi
-
-          curl -s -u "${JIRA_USERNAME}:${JIRA_API_TOKEN}" \
-            -X POST -H "Content-Type: application/json" \
-            --data "{\"transition\": {\"id\": \"41\"}}" \
-            "${JIRA_BASE_URL}/rest/api/2/issue/${jira_issue_key}/transitions"
-
-          echo "Moved Jira issue ${jira_issue_key} to Done"

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

@@ -1,7 +1,6 @@
-# This workflow allows any user to add one of the `awaiting-review`, `awaiting-author`, `WIP`,
-# 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.
+# This workflow allows any user to add one of the `awaiting-review`, `awaiting-author`, or `WIP` labels,
+# by commenting on the PR or issue.
+# Other labels from this set are removed automatically at the same time.
 
 name: Label PR based on Comment
 
@@ -11,7 +10,7 @@ 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'))
+    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'))
     runs-on: ubuntu-latest
 
     steps:
@@ -26,7 +25,6 @@ jobs:
           const awaitingReview = commentLines.includes('awaiting-review');
           const awaitingAuthor = commentLines.includes('awaiting-author');
           const wip = commentLines.includes('WIP');
-          const releaseCI = commentLines.includes('release-ci');
 
           if (awaitingReview || awaitingAuthor || wip) {
             await github.rest.issues.removeLabel({ owner, repo, issue_number, name: 'awaiting-review' }).catch(() => {});
@@ -43,7 +41,3 @@ jobs:
           if (wip) {
             await github.rest.issues.addLabels({ owner, repo, issue_number, labels: ['WIP'] });
           }
-
-          if (releaseCI) {
-            await github.rest.issues.addLabels({ owner, repo, issue_number, labels: ['release-ci'] });
-          }

.github/workflows/nix-ci.yml

@@ -6,6 +6,7 @@ on:
     tags:
       - '*'
   pull_request:
+    types: [opened, synchronize, reopened, labeled]
   merge_group:
 
 concurrency:
@@ -13,36 +14,18 @@ concurrency:
   cancel-in-progress: true
 
 jobs:
-  # see ci.yml
-  configure:
-    runs-on: ubuntu-latest
-    outputs:
-      matrix: ${{ steps.set-matrix.outputs.result }}
-    steps:
-      - name: Configure build matrix
-        id: set-matrix
-        uses: actions/github-script@v7
-        with:
-          script: |
-            let large = ${{ github.repository == 'leanprover/lean4' }};
-            let matrix = [
-              {
-                "name": "Nix Linux",
-                "os": large ? "nscloud-ubuntu-22.04-amd64-8x8" : "ubuntu-latest",
-              }
-            ];
-            console.log(`matrix:\n${JSON.stringify(matrix, null, 2)}`);
-            return matrix;
-
   Build:
-    needs: [configure]
     runs-on: ${{ matrix.os }}
     defaults:
       run:
         shell: nix run .#ciShell -- bash -euxo pipefail {0}
     strategy:
       matrix:
-        include: ${{fromJson(needs.configure.outputs.matrix)}}
+        include:
+          - name: Nix Linux
+            os: ubuntu-latest
+          #- name: Nix macOS
+          #  os: macos-latest
       # complete all jobs
       fail-fast: false
     name: ${{ matrix.name }}
@@ -50,19 +33,18 @@ jobs:
       NIX_BUILD_ARGS: --print-build-logs --fallback
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v3
         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 }}
       - name: Set Up Nix Cache
-        uses: actions/cache@v4
+        uses: actions/cache@v3
         with:
           path: nix-store-cache
           key: ${{ matrix.name }}-nix-store-cache-${{ github.sha }}
           # fall back to (latest) previous cache
           restore-keys: |
             ${{ matrix.name }}-nix-store-cache
-          save-always: true
       - name: Further Set Up Nix Cache
         shell: bash -euxo pipefail {0}
         run: |
@@ -79,14 +61,13 @@ jobs:
           sudo mkdir -m0770 -p /nix/var/cache/ccache
           sudo chown -R $USER /nix/var/cache/ccache
       - name: Setup CCache Cache
-        uses: actions/cache@v4
+        uses: actions/cache@v3
         with:
           path: /nix/var/cache/ccache
           key: ${{ matrix.name }}-nix-ccache-${{ github.sha }}
           # fall back to (latest) previous cache
           restore-keys: |
             ${{ matrix.name }}-nix-ccache
-          save-always: true
       - name: Further Set Up CCache Cache
         run: |
           sudo chown -R root:nixbld /nix/var/cache
@@ -105,7 +86,7 @@ jobs:
         continue-on-error: true
       - name: Build manual
         run: |
-          nix build $NIX_BUILD_ARGS --update-input lean --no-write-lock-file ./doc#{lean-mdbook,leanInk,alectryon,inked} -o push-doc
+          nix build $NIX_BUILD_ARGS --update-input lean --no-write-lock-file ./doc#{lean-mdbook,leanInk,alectryon,test,inked} -o push-doc
           nix build $NIX_BUILD_ARGS --update-input lean --no-write-lock-file ./doc
           # https://github.com/netlify/cli/issues/1809
           cp -r --dereference ./result ./dist
@@ -148,3 +129,5 @@ jobs:
       - name: Fixup CCache Cache
         run: |
           sudo chown -R $USER /nix/var/cache
+      - name: CCache stats
+        run: CCACHE_DIR=/nix/var/cache/ccache nix run .#nixpkgs.ccache -- -s

.github/workflows/pr-release.yml

@@ -126,22 +126,22 @@ jobs:
           if [ "$NIGHTLY_SHA" = "$MERGE_BASE_SHA" ]; then
             echo "The merge base of this PR coincides with the nightly release"
 
-            BATTERIES_REMOTE_TAGS="$(git ls-remote https://github.com/leanprover-community/batteries.git nightly-testing-"$MOST_RECENT_NIGHTLY")"
+            STD_REMOTE_TAGS="$(git ls-remote https://github.com/leanprover/std4.git nightly-testing-"$MOST_RECENT_NIGHTLY")"
             MATHLIB_REMOTE_TAGS="$(git ls-remote https://github.com/leanprover-community/mathlib4.git nightly-testing-"$MOST_RECENT_NIGHTLY")"
 
-            if [[ -n "$BATTERIES_REMOTE_TAGS" ]]; then
-              echo "... and Batteries has a 'nightly-testing-$MOST_RECENT_NIGHTLY' tag."
+            if [[ -n "$STD_REMOTE_TAGS" ]]; then
+              echo "... and Std has a 'nightly-testing-$MOST_RECENT_NIGHTLY' tag."
               MESSAGE=""
 
               if [[ -n "$MATHLIB_REMOTE_TAGS" ]]; then
-                echo "... and Mathlib has a 'nightly-testing-$MOST_RECENT_NIGHTLY' tag."
+                echo "... and Mathlib has a 'nightly-testing-$MOST_RECENT_NIGHTLY' tag."    
               else
                 echo "... but Mathlib does not yet have a 'nightly-testing-$MOST_RECENT_NIGHTLY' tag."
                 MESSAGE="- ❗ Mathlib CI can not be attempted yet, as the \`nightly-testing-$MOST_RECENT_NIGHTLY\` tag does not exist there yet. We will retry when you push more commits. If you rebase your branch onto \`nightly-with-mathlib\`, Mathlib CI should run now."
               fi
             else
-              echo "... but Batteries does not yet have a 'nightly-testing-$MOST_RECENT_NIGHTLY' tag."
-              MESSAGE="- ❗ Batteries CI can not be attempted yet, as the \`nightly-testing-$MOST_RECENT_NIGHTLY\` tag does not exist there yet. We will retry when you push more commits. If you rebase your branch onto \`nightly-with-mathlib\`, Batteries CI should run now."
+              echo "... but Std does not yet have a 'nightly-testing-$MOST_RECENT_NIGHTLY' tag."
+              MESSAGE="- ❗ Std CI can not be attempted yet, as the \`nightly-testing-$MOST_RECENT_NIGHTLY\` tag does not exist there yet. We will retry when you push more commits. If you rebase your branch onto \`nightly-with-mathlib\`, Std CI should run now."
             fi
 
           else
@@ -149,9 +149,9 @@ jobs:
             echo "but 'git merge-base origin/master HEAD' reported: $MERGE_BASE_SHA"
             git -C lean4.git log -10 origin/master
 
-            git -C lean4.git fetch origin nightly-with-mathlib
+            git -C lean4.git fetch origin nightly-with-mathlib 
             NIGHTLY_WITH_MATHLIB_SHA="$(git -C lean4.git rev-parse "origin/nightly-with-mathlib")"
-            MESSAGE="- ❗ Batteries/Mathlib CI will not be attempted unless your PR branches off the \`nightly-with-mathlib\` branch. Try \`git rebase $MERGE_BASE_SHA --onto $NIGHTLY_WITH_MATHLIB_SHA\`."
+            MESSAGE="- ❗ Std/Mathlib CI will not be attempted unless your PR branches off the \`nightly-with-mathlib\` branch. Try \`git rebase $MERGE_BASE_SHA --onto $NIGHTLY_WITH_MATHLIB_SHA\`."
           fi
 
           if [[ -n "$MESSAGE" ]]; then
@@ -163,8 +163,7 @@ jobs:
             # so keep in sync
 
             # Use GitHub API to check if a comment already exists
-            existing_comment="$(curl --retry 3 --location --silent \
-                                    -H "Authorization: token ${{ secrets.MATHLIB4_BOT }}" \
+            existing_comment="$(curl -L -s -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-mathlib4-bot"))')"
@@ -224,27 +223,27 @@ jobs:
               description: description,
             });
 
-      # We next automatically create a Batteries branch using this toolchain.
-      # Batteries doesn't itself have a mechanism to report results of CI from this branch back to Lean
-      # Instead this is taken care of by Mathlib CI, which will fail if Batteries fails.
+      # We next automatically create a Std branch using this toolchain.
+      # Std doesn't itself have a mechanism to report results of CI from this branch back to Lean
+      # Instead this is taken care of by Mathlib CI, which will fail if Std fails.
       - name: Cleanup workspace
         if: steps.workflow-info.outputs.pullRequestNumber != '' && steps.ready.outputs.mathlib_ready == 'true'
         run: |
           sudo rm -rf ./*
 
-      # Checkout the Batteries repository with all branches
-      - name: Checkout Batteries repository
+      # Checkout the Std repository with all branches
+      - name: Checkout Std repository
         if: steps.workflow-info.outputs.pullRequestNumber != '' && steps.ready.outputs.mathlib_ready == 'true'
-        uses: actions/checkout@v4
+        uses: actions/checkout@v3
         with:
-          repository: leanprover-community/batteries
+          repository: leanprover/std4
           token: ${{ secrets.MATHLIB4_BOT }}
           ref: nightly-testing
           fetch-depth: 0 # This ensures we check out all tags and branches.
 
       - name: Check if tag exists
         if: steps.workflow-info.outputs.pullRequestNumber != '' && steps.ready.outputs.mathlib_ready == 'true'
-        id: check_batteries_tag
+        id: check_std_tag
         run: |
           git config user.name "leanprover-community-mathlib4-bot"
           git config user.email "leanprover-community-mathlib4-bot@users.noreply.github.com"
@@ -252,7 +251,7 @@ jobs:
           if git ls-remote --heads --tags --exit-code origin "nightly-testing-${MOST_RECENT_NIGHTLY}" >/dev/null; then
             BASE="nightly-testing-${MOST_RECENT_NIGHTLY}"
           else
-            echo "This shouldn't be possible: couldn't find a 'nightly-testing-${MOST_RECENT_NIGHTLY}' tag at Batteries. Falling back to 'nightly-testing'."
+            echo "This shouldn't be possible: couldn't find a 'nightly-testing-${MOST_RECENT_NIGHTLY}' tag at Std. Falling back to 'nightly-testing'."
             BASE=nightly-testing
           fi
 
@@ -269,7 +268,7 @@ jobs:
           else
             echo "Branch already exists, pushing an empty commit."
             git switch lean-pr-testing-${{ steps.workflow-info.outputs.pullRequestNumber }}
-            # The Batteries `nightly-testing` or `nightly-testing-YYYY-MM-DD` branch may have moved since this branch was created, so merge their changes.
+            # The Std `nightly-testing` or `nightly-testing-YYYY-MM-DD` branch may have moved since this branch was created, so merge their changes.
             # (This should no longer be possible once `nightly-testing-YYYY-MM-DD` is a tag, but it is still safe to merge.)
             git merge "$BASE" --strategy-option ours --no-commit --allow-unrelated-histories
             git commit --allow-empty -m "Trigger CI for https://github.com/leanprover/lean4/pull/${{ steps.workflow-info.outputs.pullRequestNumber }}"
@@ -292,20 +291,13 @@ jobs:
       # Checkout the mathlib4 repository with all branches
       - name: Checkout mathlib4 repository
         if: steps.workflow-info.outputs.pullRequestNumber != '' && steps.ready.outputs.mathlib_ready == 'true'
-        uses: actions/checkout@v4
+        uses: actions/checkout@v3
         with:
           repository: leanprover-community/mathlib4
           token: ${{ secrets.MATHLIB4_BOT }}
           ref: nightly-testing
           fetch-depth: 0 # This ensures we check out all tags and branches.
 
-      - name: install elan
-        run: |
-          set -o pipefail
-          curl -sSfL https://github.com/leanprover/elan/releases/download/v3.0.0/elan-x86_64-unknown-linux-gnu.tar.gz | tar xz
-          ./elan-init -y --default-toolchain none
-          echo "$HOME/.elan/bin" >> "${GITHUB_PATH}"
-
       - name: Check if tag exists
         if: steps.workflow-info.outputs.pullRequestNumber != '' && steps.ready.outputs.mathlib_ready == 'true'
         id: check_mathlib_tag
@@ -329,17 +321,15 @@ jobs:
             git switch -c lean-pr-testing-${{ steps.workflow-info.outputs.pullRequestNumber }} "$BASE"
             echo "leanprover/lean4-pr-releases:pr-release-${{ steps.workflow-info.outputs.pullRequestNumber }}" > lean-toolchain
             git add lean-toolchain
-            sed -i 's,require "leanprover-community" / "batteries" @ git ".\+",require "leanprover-community" / "batteries" @ git "lean-pr-testing-${{ steps.workflow-info.outputs.pullRequestNumber }}",' lakefile.lean
-            lake update batteries
-            git add lakefile.lean lake-manifest.json
+            sed -i "s/require std from git \"https:\/\/github.com\/leanprover\/std4\" @ \".\+\"/require std from git \"https:\/\/github.com\/leanprover\/std4\" @ \"nightly-testing-${MOST_RECENT_NIGHTLY}\"/" lakefile.lean
+            git add lakefile.lean
             git commit -m "Update lean-toolchain for testing https://github.com/leanprover/lean4/pull/${{ steps.workflow-info.outputs.pullRequestNumber }}"
           else
-            echo "Branch already exists, merging $BASE and bumping Batteries."
+            echo "Branch already exists, pushing an empty commit."
             git switch lean-pr-testing-${{ steps.workflow-info.outputs.pullRequestNumber }}
             # The Mathlib `nightly-testing` branch or `nightly-testing-YYYY-MM-DD` tag may have moved since this branch was created, so merge their changes.
             # (This should no longer be possible once `nightly-testing-YYYY-MM-DD` is a tag, but it is still safe to merge.)
             git merge "$BASE" --strategy-option ours --no-commit --allow-unrelated-histories
-            lake update batteries
             git commit --allow-empty -m "Trigger CI for https://github.com/leanprover/lean4/pull/${{ steps.workflow-info.outputs.pullRequestNumber }}"
           fi
 

.github/workflows/restart-on-label.yml

@@ -1,35 +0,0 @@
-name: Restart by label
-on:
-  pull_request_target:
-    types:
-      - unlabeled
-      - labeled
-jobs:
-  restart-on-label:
-    runs-on: ubuntu-latest
-    if: contains(github.event.label.name, 'merge-ci') || contains(github.event.label.name, 'release-ci')
-    steps:
-    - run: |
-        # Finding latest CI workflow run on current pull request
-        # (unfortunately cannot search by PR number, only base branch,
-        # and that is't even unique given PRs from forks, but the risk
-        # of confusion is low and the danger is mild)
-        echo "Trying to find a run with branch $head_ref and commit $head_sha"
-        run_id="$(gh run list -e pull_request -b "$head_ref" -c "$head_sha" \
-          --workflow 'CI' --limit 1 --json databaseId --jq '.[0].databaseId')"
-        echo "Run id: ${run_id}"
-        gh run view "$run_id"
-        echo "Cancelling (just in case)"
-        gh run cancel "$run_id" || echo "(failed)"
-        echo "Waiting for 30s"
-        sleep 30
-        gh run view "$run_id"
-        echo "Rerunning"
-        gh run rerun "$run_id"
-        gh run view "$run_id"
-      shell: bash
-      env:
-        head_ref: ${{ github.head_ref }}
-        head_sha: ${{ github.event.pull_request.head.sha }}
-        GH_TOKEN: ${{ github.token }}
-        GH_REPO: ${{ github.repository }}

.github/workflows/update-stage0.yml

@@ -23,7 +23,7 @@ jobs:
     # This action should push to an otherwise protected branch, so it
     # uses a deploy key with write permissions, as suggested at
     # https://stackoverflow.com/a/76135647/946226
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v3
       with:
         ssh-key: ${{secrets.STAGE0_SSH_KEY}}
     - run: echo "should_update_stage0=yes" >> "$GITHUB_ENV"
@@ -47,7 +47,7 @@ jobs:
     #  uses: DeterminateSystems/magic-nix-cache-action@v2
     - if: env.should_update_stage0 == 'yes'
       name: Restore Build Cache
-      uses: actions/cache/restore@v4
+      uses: actions/cache/restore@v3
       with:
         path: nix-store-cache
         key: Nix Linux-nix-store-cache-${{ github.sha }}

.gitignore

@@ -4,10 +4,8 @@
 *.lock
 .lake
 lake-manifest.json
-/build
-/src/lakefile.toml
-/tests/lakefile.toml
-/lakefile.toml
+build
+!/src/lake/Lake/Build
 GPATH
 GRTAGS
 GSYMS

CMakeLists.txt

@@ -30,35 +30,6 @@ if(NOT (DEFINED STAGE0_CMAKE_EXECUTABLE_SUFFIX))
     set(STAGE0_CMAKE_EXECUTABLE_SUFFIX "${CMAKE_EXECUTABLE_SUFFIX}")
 endif()
 
-# Don't do anything with cadical on wasm
-if (NOT ${CMAKE_SYSTEM_NAME} MATCHES "Emscripten")
-  # On CI Linux, we source cadical from Nix instead; see flake.nix
-  find_program(CADICAL cadical)
-  if(NOT CADICAL)
-    set(CADICAL_CXX c++)
-    find_program(CCACHE ccache)
-    if(CCACHE)
-      set(CADICAL_CXX "${CCACHE} ${CADICAL_CXX}")
-    endif()
-    # missing stdio locking API on Windows
-    if(${CMAKE_SYSTEM_NAME} MATCHES "Windows")
-      string(APPEND CADICAL_CXXFLAGS " -DNUNLOCKED")
-    endif()
-    ExternalProject_add(cadical
-      PREFIX cadical
-      GIT_REPOSITORY https://github.com/arminbiere/cadical
-      GIT_TAG rel-1.9.5
-      CONFIGURE_COMMAND ""
-      # https://github.com/arminbiere/cadical/blob/master/BUILD.md#manual-build
-      BUILD_COMMAND $(MAKE) -f ${CMAKE_SOURCE_DIR}/src/cadical.mk CMAKE_EXECUTABLE_SUFFIX=${CMAKE_EXECUTABLE_SUFFIX} CXX=${CADICAL_CXX} CXXFLAGS=${CADICAL_CXXFLAGS}
-      BUILD_IN_SOURCE ON
-      INSTALL_COMMAND "")
-    set(CADICAL ${CMAKE_BINARY_DIR}/cadical/cadical${CMAKE_EXECUTABLE_SUFFIX} CACHE FILEPATH "path to cadical binary" FORCE)
-    set(EXTRA_DEPENDS "cadical")
-  endif()
-  list(APPEND CL_ARGS -DCADICAL=${CADICAL})
-endif()
-
 ExternalProject_add(stage0
   SOURCE_DIR "${LEAN_SOURCE_DIR}/stage0"
   SOURCE_SUBDIR src

CMakePresets.json

@@ -1,83 +0,0 @@
-{
-  "version": 2,
-  "cmakeMinimumRequired": {
-    "major": 3,
-    "minor": 10,
-    "patch": 0
-  },
-  "configurePresets": [
-    {
-      "name": "release",
-      "displayName": "Default development optimized build config",
-      "generator": "Unix Makefiles",
-      "binaryDir": "${sourceDir}/build/release"
-    },
-    {
-      "name": "debug",
-      "displayName": "Debug build config",
-      "cacheVariables": {
-        "CMAKE_BUILD_TYPE": "Debug"
-      },
-      "generator": "Unix Makefiles",
-      "binaryDir": "${sourceDir}/build/debug"
-    },
-    {
-      "name": "sanitize",
-      "displayName": "Sanitize build config",
-      "cacheVariables": {
-        "LEAN_EXTRA_CXX_FLAGS": "-fsanitize=address,undefined",
-        "LEANC_EXTRA_FLAGS": "-fsanitize=address,undefined -fsanitize-link-c++-runtime",
-        "SMALL_ALLOCATOR": "OFF",
-        "BSYMBOLIC": "OFF"
-      },
-      "generator": "Unix Makefiles",
-      "binaryDir": "${sourceDir}/build/sanitize"
-    },
-    {
-      "name": "sandebug",
-      "inherits": ["debug", "sanitize"],
-      "displayName": "Sanitize+debug build config",
-      "binaryDir": "${sourceDir}/build/sandebug"
-    }
-  ],
-  "buildPresets": [
-    {
-      "name": "release",
-      "configurePreset": "release"
-    },
-    {
-      "name": "debug",
-      "configurePreset": "debug"
-    },
-    {
-      "name": "sanitize",
-      "configurePreset": "sanitize"
-    },
-    {
-      "name": "sandebug",
-      "configurePreset": "sandebug"
-    }
-  ],
-  "testPresets": [
-    {
-      "name": "release",
-      "configurePreset": "release",
-      "output": {"outputOnFailure": true, "shortProgress": true}
-    },
-    {
-      "name": "debug",
-      "configurePreset": "debug",
-      "inherits": "release"
-    },
-    {
-      "name": "sanitize",
-      "configurePreset": "sanitize",
-      "inherits": "release"
-    },
-    {
-      "name": "sandebug",
-      "configurePreset": "sandebug",
-      "inherits": "release"
-    }
-  ]
-}

CODEOWNERS

@@ -42,6 +42,4 @@
 /src/Lean/Elab/Tactic/Guard.lean @digama0
 /src/Init/Guard.lean @digama0
 /src/Lean/Server/CodeActions/ @digama0
-/src/Std/ @TwoFX
-/src/Std/Tactic/BVDecide/ @hargoniX
-/src/Lean/Elab/Tactic/BVDecide/ @hargoniX
+

CONTRIBUTING.md

@@ -63,20 +63,6 @@ Because the change will be squashed, there is no need to polish the commit messa
 Reviews and Feedback:
 ----
 
-The lean4 repo is managed by the Lean FRO's *triage team* that aims to provide initial feedback on new bug reports, PRs, and RFCs weekly.
-This feedback generally consists of prioritizing the ticket using one of the following categories:
-* label `P-high`: We will work on this issue
-* label `P-medium`: We may work on this issue if we find the time
-* label `P-low`: We are not planning to work on this issue
-* *closed*: This issue is already fixed, it is not an issue, or is not sufficiently compatible with our roadmap for the project and we will not work on it nor accept external contributions on it
-
-For *bug reports*, the listed priority reflects our commitment to fixing the issue.
-It is generally indicative but not necessarily identical to the priority an external contribution addressing this bug would receive.
-For *PRs* and *RFCs*, the priority reflects our commitment to reviewing them and getting them to an acceptable state.
-Accepted RFCs are marked with the label `RFC accepted` and afterwards assigned a new "implementation" priority as with bug reports.
-
-General guidelines for interacting with reviews and feedback:
-
 **Be Patient**: Given the limited number of full-time maintainers and the volume of PRs, reviews may take some time.
 
 **Engage Constructively**: Always approach feedback positively and constructively. Remember, reviews are about ensuring the best quality for the project, not personal criticism.

LICENSES

@@ -1341,33 +1341,3 @@ whether future versions of the GNU Lesser General Public License shall
 apply, that proxy's public statement of acceptance of any version is
 permanent authorization for you to choose that version for the
 Library.
-==============================================================================
-CaDiCaL is under the MIT License:
-==============================================================================
-MIT License
-
-Copyright (c) 2016-2021 Armin Biere, Johannes Kepler University Linz, Austria
-Copyright (c) 2020-2021 Mathias Fleury, Johannes Kepler University Linz, Austria
-Copyright (c) 2020-2021 Nils Froleyks, Johannes Kepler University Linz, Austria
-Copyright (c) 2022-2024 Katalin Fazekas, Vienna University of Technology, Austria
-Copyright (c) 2021-2024 Armin Biere, University of Freiburg, Germany
-Copyright (c) 2021-2024 Mathias Fleury, University of Freiburg, Germany
-Copyright (c) 2023-2024 Florian Pollitt, University of Freiburg, Germany
-
-Permission is hereby granted, free of charge, to any person obtaining a copy
-of this software and associated documentation files (the "Software"), to deal
-in the Software without restriction, including without limitation the rights
-to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-copies of the Software, and to permit persons to whom the Software is
-furnished to do so, subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in all
-copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-SOFTWARE.

README.md

@@ -22,4 +22,4 @@ Please read our [Contribution Guidelines](CONTRIBUTING.md) first.
 
 # Building from Source
 
-See [Building Lean](https://lean-lang.org/lean4/doc/make/index.html) (documentation source: [doc/make/index.md](doc/make/index.md)).
+See [Building Lean](https://lean-lang.org/lean4/doc/make/index.html).

debug.log

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

doc/BoolExpr.lean

@@ -1,4 +1,4 @@
-open Batteries
+open Std
 open Lean
 
 inductive BoolExpr where

doc/char.md

@@ -1,11 +1 @@
 # Characters
-
-A value of type `Char`, also known as a character, is a [Unicode scalar value](https://www.unicode.org/glossary/#unicode_scalar_value). It is represented using an unsigned 32-bit integer and is statically guaranteed to be a valid Unicode scalar value.
-
-Syntactically, character literals are enclosed in single quotes.
-```lean
-#eval 'a' -- 'a'
-#eval '∀' -- '∀'
-```
-
-Characters are ordered and can be decidably compared using the relational operators `=`, `<`, `≤`, `>`, `≥`.

doc/dev/bootstrap.md

@@ -73,7 +73,7 @@ update the archived C source code of the stage 0 compiler in `stage0/src`.
 The github repository will automatically update stage0 on `master` once
 `src/stdlib_flags.h` and `stage0/src/stdlib_flags.h` are out of sync.
 
-If you have write access to the lean4 repository, you can also manually
+If you have write access to the lean4 repository, you can also also manually
 trigger that process, for example to be able to use new features in the compiler itself.
 You can do that on <https://github.com/leanprover/lean4/actions/workflows/update-stage0.yml>
 or using Github CLI with
@@ -84,12 +84,10 @@ gh workflow run update-stage0.yml
 Leaving stage0 updates to the CI automation is preferable, but should you need
 to do it locally, you can use `make update-stage0-commit` in `build/release` to
 update `stage0` from `stage1` or `make -C stageN update-stage0-commit` to
-update from another stage. This command will automatically stage the updated files
-and introduce a commit,so make sure to commit your work before that.
+update from another stage.
 
-If you rebased the branch (either onto a newer version of `master`, or fixing
-up some commits prior to the stage0 update, recreate the stage0 update commits.
-The script `script/rebase-stage0.sh` can be used for that.
+This command will automatically stage the updated files and introduce a commit,
+so make sure to commit your work before that.
 
 The CI should prevent PRs with changes to stage0 (besides `stdlib_flags.h`)
 from entering `master` through the (squashing!) merge queue, and label such PRs
@@ -97,7 +95,6 @@ with the `changes-stage0` label. Such PRs should have a cleaned up history,
 with separate stage0 update commits; then coordinate with the admins to merge
 your PR using rebase merge, bypassing the merge queue.
 
-
 ## Further Bootstrapping Complications
 
 As written above, changes in meta code in the current stage usually will only

doc/dev/debugging.md

@@ -5,7 +5,7 @@ Some notes on how to debug Lean, which may also be applicable to debugging Lean
 
 ## Tracing
 
-In `CoreM` and derived monads, we use `trace[traceCls] "msg with {interpolations}"` to fill the structured trace viewable with `set_option trace.traceCls true`.
+In `CoreM` and derived monads, we use `trace![traceCls] "msg with {interpolations}"` to fill the structured trace viewable with `set_option trace.traceCls true`.
 New trace classes have to be registered using `registerTraceClass` first.
 
 Notable trace classes:
@@ -22,9 +22,7 @@ Notable trace classes:
 
 In pure contexts or when execution is aborted before the messages are finally printed, one can instead use the term `dbg_trace "msg with {interpolations}"; val` (`;` can also be replaced by a newline), which will print the message to stderr before evaluating `val`. `dbgTraceVal val` can be used as a shorthand for `dbg_trace "{val}"; val`.
 Note that if the return value is not actually used, the trace code is silently dropped as well.
-
-By default, such stderr output is buffered and shown as messages after a command has been elaborated, which is necessary to ensure deterministic ordering of messages under parallelism.
-If Lean aborts the process before it can finish the command or takes too long to do that, using `-DstderrAsMessages=false` avoids this buffering and shows `dbg_trace` output (but not `trace`s or other diagnostics) immediately.
+In the language server, stderr output is buffered and shown as messages after a command has been elaborated, unless the option `server.stderrAsMessages` is deactivated.
 
 ## Debuggers
 

doc/dev/ffi.md

@@ -53,59 +53,10 @@ In the case of `@[extern]` all *irrelevant* types are removed first; see next se
   Its runtime value is either a pointer to an opaque bignum object or, if the lowest bit of the "pointer" is 1 (`lean_is_scalar`), an encoded unboxed natural number (`lean_box`/`lean_unbox`).
 * A universe `Sort u`, type constructor `... → Sort u`, or proposition `p : Prop` is *irrelevant* and is either statically erased (see above) or represented as a `lean_object *` with the runtime value `lean_box(0)`
 * Any other type is represented by `lean_object *`.
-  Its runtime value is a pointer to an object of a subtype of `lean_object` (see the "Inductive types" section below) or the unboxed value `lean_box(cidx)` for the `cidx`th constructor of an inductive type if this constructor does not have any relevant parameters.
+  Its runtime value is a pointer to an object of a subtype of `lean_object` (see respective declarations in `lean.h`) or the unboxed value `lean_box(cidx)` for the `cidx`th constructor of an inductive type if this constructor does not have any relevant parameters.
 
   Example: the runtime value of `u : Unit` is always `lean_box(0)`.
 
-#### Inductive types
-
-For inductive types which are in the fallback `lean_object *` case above and not trivial constructors, the type is stored as a `lean_ctor_object`, and `lean_is_ctor` will return true. A `lean_ctor_object` stores the constructor index in the header, and the fields are stored in the `m_objs` portion of the object.
-
-The memory order of the fields is derived from the types and order of the fields in the declaration. They are ordered as follows:
-
-* Non-scalar fields stored as `lean_object *`
-* Fields of type `USize`
-* Other scalar fields, in decreasing order by size
-
-Within each group the fields are ordered in declaration order. **Warning**: Trivial wrapper types still count toward a field being treated as non-scalar for this purpose.
-
-* To access fields of the first kind, use `lean_ctor_get(val, i)` to get the `i`th non-scalar field.
-* To access `USize` fields, use `lean_ctor_get_usize(val, n+i)` to get the `i`th usize field and `n` is the total number of fields of the first kind.
-* To access other scalar fields, use `lean_ctor_get_uintN(val, off)` or `lean_ctor_get_usize(val, off)` as appropriate. Here `off` is the byte offset of the field in the structure, starting at `n*sizeof(void*)` where `n` is the number of fields of the first two kinds.
-
-For example, a structure such as
-```lean
-structure S where
-  ptr_1 : Array Nat
-  usize_1 : USize
-  sc64_1 : UInt64
-  ptr_2 : { x : UInt64 // x > 0 } -- wrappers don't count as scalars
-  sc64_2 : Float -- `Float` is 64 bit
-  sc8_1 : Bool
-  sc16_1 : UInt16
-  sc8_2 : UInt8
-  sc64_3 : UInt64
-  usize_2 : USize
-  ptr_3 : Char -- trivial wrapper around `UInt32`
-  sc32_1 : UInt32
-  sc16_2 : UInt16
-```
-would get re-sorted into the following memory order:
-
-* `S.ptr_1` - `lean_ctor_get(val, 0)`
-* `S.ptr_2` - `lean_ctor_get(val, 1)`
-* `S.ptr_3` - `lean_ctor_get(val, 2)`
-* `S.usize_1` - `lean_ctor_get_usize(val, 3)`
-* `S.usize_2` - `lean_ctor_get_usize(val, 4)`
-* `S.sc64_1` - `lean_ctor_get_uint64(val, sizeof(void*)*5)`
-* `S.sc64_2` - `lean_ctor_get_float(val, sizeof(void*)*5 + 8)`
-* `S.sc64_3` - `lean_ctor_get_uint64(val, sizeof(void*)*5 + 16)`
-* `S.sc32_1` - `lean_ctor_get_uint32(val, sizeof(void*)*5 + 24)`
-* `S.sc16_1` - `lean_ctor_get_uint16(val, sizeof(void*)*5 + 28)`
-* `S.sc16_2` - `lean_ctor_get_uint16(val, sizeof(void*)*5 + 30)`
-* `S.sc8_1` - `lean_ctor_get_uint8(val, sizeof(void*)*5 + 32)`
-* `S.sc8_2` - `lean_ctor_get_uint8(val, sizeof(void*)*5 + 33)`
-
 ### Borrowing
 
 By default, all `lean_object *` parameters of an `@[extern]` function are considered *owned*, i.e. the external code is passed a "virtual RC token" and is responsible for passing this token along to another consuming function (exactly once) or freeing it via `lean_dec`.

doc/dev/release_checklist.md

@@ -5,11 +5,7 @@ See below for the checklist for release candidates.
 
 We'll use `v4.6.0` as the intended release version as a running example.
 
-- One week before the planned release, ensure that
-  (1) someone has written the release notes and
-  (2) someone has written the first draft of the release blog post.
-  If there is any material in `./releases_drafts/` on the `releases/v4.6.0` branch, then the release notes are not done.
-  (See the section "Writing the release notes".)
+- One week before the planned release, ensure that someone has written the first draft of the release blog post
 - `git checkout releases/v4.6.0`
   (This branch should already exist, from the release candidates.)
 - `git pull`
@@ -17,6 +13,13 @@ We'll use `v4.6.0` as the intended release version as a running example.
   - `set(LEAN_VERSION_MINOR 6)` (for whichever `6` is appropriate)
   - `set(LEAN_VERSION_IS_RELEASE 1)`
   - (both of these should already be in place from the release candidates)
+- It is possible that the `v4.6.0` section of `RELEASES.md` is out of sync between
+  `releases/v4.6.0` and `master`. This should be reconciled:
+  - Run `git diff master RELEASES.md`.
+  - You should expect to see additons on `master` in the `v4.7.0-rc1` section; ignore these.
+    (i.e. the new release notes for the upcoming release candidate).
+  - Reconcile discrepancies in the `v4.6.0` section,
+    usually via copy and paste and a commit to `releases/v4.6.0`.
 - `git tag v4.6.0`
 - `git push $REMOTE v4.6.0`, where `$REMOTE` is the upstream Lean repository (e.g., `origin`, `upstream`)
 - Now wait, while CI runs.
@@ -27,9 +30,8 @@ We'll use `v4.6.0` as the intended release version as a running example.
     you may want to start on the release candidate checklist now.
 - Go to https://github.com/leanprover/lean4/releases and verify that the `v4.6.0` release appears.
   - Edit the release notes on Github to select the "Set as the latest release".
-  - Follow the instructions in creating a release candidate for the "GitHub release notes" step,
-    now that we have a written `RELEASES.md` section.
-    Do a quick sanity check.
+  - Copy and paste the Github release notes from the previous releases candidate for this version
+    (e.g. `v4.6.0-rc1`), and quickly sanity check.
 - Next, we will move a curated list of downstream repos to the latest stable release.
   - For each of the repositories listed below:
     - Make a PR to `master`/`main` changing the toolchain to `v4.6.0`
@@ -44,16 +46,17 @@ We'll use `v4.6.0` as the intended release version as a running example.
   - We do this for the repositories:
     - [lean4checker](https://github.com/leanprover/lean4checker)
       - No dependencies
+      - Note: `lean4checker` uses a different version tagging scheme: use `toolchain/v4.6.0` rather than `v4.6.0`.
       - Toolchain bump PR
       - Create and push the tag
       - Merge the tag into `stable`
-    - [Batteries](https://github.com/leanprover-community/batteries)
+    - [Std](https://github.com/leanprover-community/std4)
       - No dependencies
       - Toolchain bump PR
       - Create and push the tag
       - Merge the tag into `stable`
     - [ProofWidgets4](https://github.com/leanprover-community/ProofWidgets4)
-      - Dependencies: `Batteries`
+      - Dependencies: `Std`
       - Note on versions and branches:
         - `ProofWidgets` uses a sequential version tagging scheme, e.g. `v0.0.29`,
           which does not refer to the toolchain being used.
@@ -62,7 +65,7 @@ We'll use `v4.6.0` as the intended release version as a running example.
       - Toolchain bump PR
       - Create and push the tag, following the version convention of the repository
     - [Aesop](https://github.com/leanprover-community/aesop)
-      - Dependencies: `Batteries`
+      - Dependencies: `Std`
       - Toolchain bump PR including updated Lake manifest
       - Create and push the tag
       - Merge the tag into `stable`
@@ -71,22 +74,18 @@ We'll use `v4.6.0` as the intended release version as a running example.
       - Toolchain bump PR including updated Lake manifest
       - Create and push the tag
       - There is no `stable` branch; skip this step
-    - [Verso](https://github.com/leanprover/verso)
-      - Dependencies: exist, but they're not part of the release workflow
-      - The `SubVerso` dependency should be compatible with _every_ Lean release simultaneously, rather than following this workflow
-      - Toolchain bump PR including updated Lake manifest
-      - Create and push the tag
-      - There is no `stable` branch; skip this step
     - [import-graph](https://github.com/leanprover-community/import-graph)
       - Toolchain bump PR including updated Lake manifest
       - Create and push the tag
       - There is no `stable` branch; skip this step
     - [Mathlib](https://github.com/leanprover-community/mathlib4)
-      - Dependencies: `Aesop`, `ProofWidgets4`, `lean4checker`, `Batteries`, `doc-gen4`, `import-graph`
+      - Dependencies: `Aesop`, `ProofWidgets4`, `lean4checker`, `Std`, `doc-gen4`, `import-graph`
       - Toolchain bump PR notes:
         - In addition to updating the `lean-toolchain` and `lakefile.lean`,
-          in `.github/workflows/lean4checker.yml` update the line
-          `git checkout v4.6.0` to the appropriate tag. 
+          in `.github/workflows/build.yml.in` in the `lean4checker` section update the line
+          `git checkout toolchain/v4.6.0` to the appropriate tag,
+          and then run `.github/workflows/mk_build_yml.sh`. Coordinate with
+          a Mathlib maintainer to get this merged.
         - Push the PR branch to the main Mathlib repository rather than a fork, or CI may not work reliably
         - Create and push the tag
         - Create a new branch from the tag, push it, and open a pull request against `stable`.
@@ -98,10 +97,6 @@ We'll use `v4.6.0` as the intended release version as a running example.
       - Toolchain bump PR including updated Lake manifest
       - Create and push the tag
       - Merge the tag into `stable`
-- The `v4.6.0` section of `RELEASES.md` is out of sync between
-  `releases/v4.6.0` and `master`. This should be reconciled:
-  - Replace the `v4.6.0` section on `master` with the `v4.6.0` section on `releases/v4.6.0`
-    and commit this to `master`.
 - Merge the release announcement PR for the Lean website - it will be deployed automatically
 - Finally, make an announcement!
   This should go in https://leanprover.zulipchat.com/#narrow/stream/113486-announce, with topic `v4.6.0`.
@@ -112,6 +107,7 @@ We'll use `v4.6.0` as the intended release version as a running example.
 
 ## Optimistic(?) time estimates:
 - Initial checks and push the tag: 30 minutes.
+- Note that if `RELEASES.md` has discrepancies this could take longer!
 - Waiting for the release: 60 minutes.
 - Fixing release notes: 10 minutes.
 - Bumping toolchains in downstream repositories, up to creating the Mathlib PR: 30 minutes.
@@ -127,8 +123,8 @@ We'll use `v4.7.0-rc1` as the intended release version in this example.
 
 - Decide which nightly release you want to turn into a release candidate.
   We will use `nightly-2024-02-29` in this example.
-- It is essential that Batteries and Mathlib already have reviewed branches compatible with this nightly.
-  - Check that both Batteries and Mathlib's `bump/v4.7.0` branch contain `nightly-2024-02-29`
+- It is essential that Std and Mathlib already have reviewed branches compatible with this nightly.
+  - Check that both Std and Mathlib's `bump/v4.7.0` branch contain `nightly-2024-02-29`
     in their `lean-toolchain`.
   - The steps required to reach that state are beyond the scope of this checklist, but see below!
 - Create the release branch from this nightly tag:
@@ -138,53 +134,55 @@ We'll use `v4.7.0-rc1` as the intended release version in this example.
     git checkout nightly-2024-02-29
     git checkout -b releases/v4.7.0
     ```
-- In `RELEASES.md` replace `Development in progress` in the `v4.7.0` section with `Release notes to be written.`
-- We will rely on automatically generated release notes for release candidates,
-  and the written release notes will be used for stable versions only.
-  It is essential to choose the nightly that will become the release candidate as early as possible, to avoid confusion.
+- In `RELEASES.md` remove `(development in progress)` from the `v4.7.0` section header.
+- Our current goal is to have written release notes only about major language features or breaking changes,
+  and to rely on automatically generated release notes for bugfixes and minor changes.
+  - Do not wait on `RELEASES.md` being perfect before creating the `release/v4.7.0` branch. It is essential to choose the nightly which will become the release candidate as early as possible, to avoid confusion.
+  - If there are major changes not reflected in `RELEASES.md` already, you may need to solicit help from the authors.
+  - Minor changes and bug fixes do not need to be documented in `RELEASES.md`: they will be added automatically on the Github release page.
+  - Commit your changes to `RELEASES.md`, and push.
+  - Remember that changes to `RELEASES.md` after you have branched `releases/v4.7.0` should also be cherry-picked back to `master`.
 - In `src/CMakeLists.txt`,
   - verify that you see `set(LEAN_VERSION_MINOR 7)` (for whichever `7` is appropriate); this should already have been updated when the development cycle began.
   - `set(LEAN_VERSION_IS_RELEASE 1)` (this should be a change; on `master` and nightly releases it is always `0`).
   - Commit your changes to `src/CMakeLists.txt`, and push.
 - `git tag v4.7.0-rc1`
 - `git push origin v4.7.0-rc1`
-- Ping the FRO Zulip that release notes need to be written. The release notes do not block completing the rest of this checklist.
 - Now wait, while CI runs.
   - You can monitor this at `https://github.com/leanprover/lean4/actions/workflows/ci.yml`, looking for the `v4.7.0-rc1` tag.
   - This step can take up to an hour.
-- (GitHub release notes) Once the release appears at https://github.com/leanprover/lean4/releases/
-  - Verify that the release is marked as a prerelease (this should have been done automatically by the CI release job).
-  - In the "previous tag" dropdown, select `v4.6.0`, and click "Generate release notes".
-    This will add a list of all the commits since the last stable version.
+- Once the release appears at https://github.com/leanprover/lean4/releases/
+  - Edit the release notes on Github to select the "Set as a pre-release box".
+  - Copy the section of `RELEASES.md` for this version into the Github release notes.
+  - Use the title "Changes since v4.6.0 (from RELEASES.md)"
+  - Then in the "previous tag" dropdown, select `v4.6.0`, and click "Generate release notes".
+  - This will add a list of all the commits since the last stable version.
+    - Delete anything already mentioned in the hand-written release notes above.
     - Delete "update stage0" commits, and anything with a completely inscrutable commit message.
+    - Briefly rearrange the remaining items by category (e.g. `simp`, `lake`, `bug fixes`),
+      but for minor items don't put any work in expanding on commit messages.
+  - (How we want to release notes to look is evolving: please update this section if it looks wrong!)
 - Next, we will move a curated list of downstream repos to the release candidate.
-  - This assumes that for each repository either:
-    * There is already a *reviewed* branch `bump/v4.7.0` containing the required adaptations.
-      The preparation of this branch is beyond the scope of this document.
-    * The repository does not need any changes to move to the new version.
+  - This assumes that there is already a *reviewed* branch `bump/v4.7.0` on each repository
+    containing the required adaptations (or no adaptations are required).
+    The preparation of this branch is beyond the scope of this document.
   - For each of the target repositories:
-    - If the repository does not need any changes (i.e. `bump/v4.7.0` does not exist) then create
-      a new PR updating `lean-toolchain` to `leanprover/lean4:v4.7.0-rc1` and running `lake update`.
-    - Otherwise:
-      - Checkout the `bump/v4.7.0` branch.
-      - Verify that the `lean-toolchain` is set to the nightly from which the release candidate was created.
-      - `git merge origin/master`
-      - Change the `lean-toolchain` to `leanprover/lean4:v4.7.0-rc1`
-      - In `lakefile.lean`, change any dependencies which were using `nightly-testing` or `bump/v4.7.0` branches
-        back to `master` or `main`, and run `lake update` for those dependencies.
-      - Run `lake build` to ensure that dependencies are found (but it's okay to stop it after a moment).
-      - `git commit`
-      - `git push`
-      - Open a PR from `bump/v4.7.0` to `master`, and either merge it yourself after CI, if appropriate,
-        or notify the maintainers that it is ready to go.
-    - Once the PR has been merged, tag `master` with `v4.7.0-rc1` and push this tag.
+    - Checkout the `bump/v4.7.0` branch.
+    - Verify that the `lean-toolchain` is set to the nightly from which the release candidate was created.
+    - `git merge origin/master`
+    - Change the `lean-toolchain` to `leanprover/lean4:v4.7.0-rc1`
+    - In `lakefile.lean`, change any dependencies which were using `nightly-testing` or `bump/v4.7.0` branches
+      back to `master` or `main`, and run `lake update` for those dependencies.
+    - Run `lake build` to ensure that dependencies are found (but it's okay to stop it after a moment).
+    - `git commit`
+    - `git push`
+    - Open a PR from `bump/v4.7.0` to `master`, and either merge it yourself after CI, if appropriate,
+      or notify the maintainers that it is ready to go.
+    - Once this PR has been merged, tag `master` with `v4.7.0-rc1` and push this tag.
   - We do this for the same list of repositories as for stable releases, see above.
     As above, there are dependencies between these, and so the process above is iterative.
     It greatly helps if you can merge the `bump/v4.7.0` PRs yourself!
-    It is essential for Mathlib CI that you then create the next `bump/v4.8.0` branch
-    for the next development cycle.
-    Set the `lean-toolchain` file on this branch to same `nightly` you used for this release.
-  - For Batteries/Aesop/Mathlib, which maintain a `nightly-testing` branch, make sure there is a tag
+  - For Std/Aesop/Mathlib, which maintain a `nightly-testing` branch, make sure there is a tag
     `nightly-testing-2024-02-29` with date corresponding to the nightly used for the release
     (create it if not), and then on the `nightly-testing` branch `git reset --hard master`, and force push.
 - Make an announcement!
@@ -194,21 +192,8 @@ We'll use `v4.7.0-rc1` as the intended release version in this example.
   Please also make sure that whoever is handling social media knows the release is out.
 - Begin the next development cycle (i.e. for `v4.8.0`) on the Lean repository, by making a PR that:
   - Updates `src/CMakeLists.txt` to say `set(LEAN_VERSION_MINOR 8)`
-  - Replaces the "release notes will be copied" text in the `v4.6.0` section of `RELEASES.md` with the
-    finalized release notes from the `releases/v4.6.0` branch.
-  - Replaces the "development in progress" in the `v4.7.0` section of `RELEASES.md` with
-    ```
-    Release candidate, release notes will be copied from the branch `releases/v4.7.0` once completed.
-    ```
-    and inserts the following section before that section:
-    ```
-    v4.8.0
-    ----------
-    Development in progress.
-    ```
-  - Removes all the entries from the `./releases_drafts/` folder.
-  - Titled "chore: begin development cycle for v4.8.0"
-
+  - Removes `(in development)` from the section heading in `RELEASES.md` for `v4.7.0`,
+    and creates a new `v4.8.0 (in development)` section heading.
 
 ## Time estimates:
 Slightly longer than the corresponding steps for a stable release.
@@ -219,7 +204,7 @@ In particular, updating the downstream repositories is significantly more work
 # Preparing `bump/v4.7.0` branches
 
 While not part of the release process per se,
-this is a brief summary of the work that goes into updating Batteries/Aesop/Mathlib to new versions.
+this is a brief summary of the work that goes into updating Std/Aesop/Mathlib to new versions.
 
 Please read https://leanprover-community.github.io/contribute/tags_and_branches.html
 
@@ -233,30 +218,12 @@ Please read https://leanprover-community.github.io/contribute/tags_and_branches.
   * This can either be done by the person managing this process directly,
     or by soliciting assistance from authors of files, or generally helpful people on Zulip!
 * Each repo has a `bump/v4.7.0` which accumulates reviewed changes adapting to new versions.
-* Once `nightly-testing` is working on a given nightly, say `nightly-2024-02-15`, we will create a PR to `bump/v4.7.0`.
-* For Mathlib, there is a script in `scripts/create-adaptation-pr.sh` that automates this process.
-* For Batteries and Aesop it is currently manual.
-* For all of these repositories, the process is the same:
+* Once `nightly-testing` is working on a given nightly, say `nightly-2024-02-15`, we:
   * Make sure `bump/v4.7.0` is up to date with `master` (by merging `master`, no PR necessary)
   * Create from `bump/v4.7.0` a `bump/nightly-2024-02-15` branch.
-  * In that branch, `git merge nightly-testing` to bring across changes from `nightly-testing`.
+  * In that branch, `git merge --squash nightly-testing` to bring across changes from `nightly-testing`.
   * Sanity check changes, commit, and make a PR to `bump/v4.7.0` from the `bump/nightly-2024-02-15` branch.
-  * Solicit review, merge the PR into `bump/v4.7.0`.
+  * Solicit review, merge the PR into `bump/v4,7,0`.
 * It is always okay to merge in the following directions:
   `master` -> `bump/v4.7.0` -> `bump/nightly-2024-02-15` -> `nightly-testing`.
   Please remember to push any merges you make to intermediate steps!
-
-# Writing the release notes
-
-We are currently trying a system where release notes are compiled all at once from someone looking through the commit history.
-The exact steps are a work in progress.
-Here is the general idea:
-
-* The work is done right on the `releases/v4.6.0` branch sometime after it is created but before the stable release is made.
-  The release notes for `v4.6.0` will later be copied to `master` when we begin a new development cycle.
-* There can be material for release notes entries in commit messages.
-* There can also be pre-written entries in `./releases_drafts`, which should be all incorporated in the release notes and then deleted from the branch.
-  See `./releases_drafts/README.md` for more information.
-* The release notes should be written from a downstream expert user's point of view.
-
-This section will be updated when the next release notes are written (for `v4.10.0`).

doc/examples/ICERM2022/ctor.lean

@@ -18,7 +18,7 @@ def ctor (mvarId : MVarId) (idx : Nat) : MetaM (List MVarId) := do
     else if h : idx - 1 < ctors.length then
       mvarId.apply (.const ctors[idx - 1] us)
     else
-      throwTacticEx `ctor mvarId "invalid index, inductive datatype has only {ctors.length} constructors"
+      throwTacticEx `ctor mvarId "invalid index, inductive datatype has only {ctors.length} contructors"
 
 open Elab Tactic
 

doc/examples/compiler/.gitignore

@@ -1 +0,0 @@
-build

doc/examples/deBruijn.lean

@@ -149,7 +149,7 @@ We now define the constant folding optimization that traverses a term if replace
 /-!
 The correctness of the `Term.constFold` is proved using induction, case-analysis, and the term simplifier.
 We prove all cases but the one for `plus` using `simp [*]`. This tactic instructs the term simplifier to
-use hypotheses such as `a = b` as rewriting/simplifications rules.
+use hypotheses such as `a = b` as rewriting/simplications rules.
 We use the `split` to break the nested `match` expression in the `plus` case into two cases.
 The local variables `iha` and `ihb` are the induction hypotheses for `a` and `b`.
 The modifier `←` in a term simplifier argument instructs the term simplifier to use the equation as a rewriting rule in

doc/examples/interp.lean

@@ -149,4 +149,4 @@ def fact : Expr ctx (Ty.fn Ty.int Ty.int) :=
            (op (·*·) (delay fun _ => app fact (op (·-·) (var stop) (val 1))) (var stop)))
   decreasing_by sorry
 
-#eval! fact.interp Env.nil 10
+#eval fact.interp Env.nil 10

doc/examples/phoas.lean

@@ -225,7 +225,7 @@ We now define the constant folding optimization that traverses a term if replace
 /-!
 The correctness of the `constFold` is proved using induction, case-analysis, and the term simplifier.
 We prove all cases but the one for `plus` using `simp [*]`. This tactic instructs the term simplifier to
-use hypotheses such as `a = b` as rewriting/simplifications rules.
+use hypotheses such as `a = b` as rewriting/simplications rules.
 We use the `split` to break the nested `match` expression in the `plus` case into two cases.
 The local variables `iha` and `ihb` are the induction hypotheses for `a` and `b`.
 The modifier `←` in a term simplifier argument instructs the term simplifier to use the equation as a rewriting rule in

doc/examples/tc.lean

@@ -29,7 +29,7 @@ inductive HasType : Expr → Ty → Prop
 
 /-!
 We can easily show that if `e` has type `t₁` and type `t₂`, then `t₁` and `t₂` must be equal
-by using the `cases` tactic. This tactic creates a new subgoal for every constructor,
+by using the the `cases` tactic. This tactic creates a new subgoal for every constructor,
 and automatically discharges unreachable cases. The tactic combinator `tac₁ <;> tac₂` applies
 `tac₂` to each subgoal produced by `tac₁`. Then, the tactic `rfl` is used to close all produced
 goals using reflexivity.
@@ -82,7 +82,7 @@ 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. The tactic `rename_i` is used to rename "inaccessible" variables.
+The proof is by induction on `e` and case analysis. The tactic `rename_i` is used to 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`.

doc/examples/test_single.sh

@@ -1,4 +1,4 @@
 #!/usr/bin/env bash
 source ../../tests/common.sh
 
-exec_check lean -Dlinter.all=false "$f"
+exec_check lean -j 0 -Dlinter.all=false "$f"

doc/examples/widgets.lean

@@ -4,18 +4,15 @@ open Lean Widget
 /-!
 # The user-widgets system
 
-Proving and programming are inherently interactive tasks.
-Lots of mathematical objects and data structures are visual in nature.
-*User widgets* let you associate custom interactive UIs
-with sections of a Lean document.
-User widgets are rendered in the Lean infoview.
+Proving and programming are inherently interactive tasks. Lots of mathematical objects and data
+structures are visual in nature. *User widgets* let you associate custom interactive UIs with
+sections of a Lean document. User widgets are rendered in the Lean infoview.
 
 ![Rubik's cube](../images/widgets_rubiks.png)
 
 ## Trying it out
 
-To try it out, type in the following code and place your cursor over the `#widget` command.
-You can also [view this manual entry in the online editor](https://live.lean-lang.org/#url=https%3A%2F%2Fraw.githubusercontent.com%2Fleanprover%2Flean4%2Fmaster%2Fdoc%2Fexamples%2Fwidgets.lean).
+To try it out, simply type in the following code and place your cursor over the `#widget` command.
 -/
 
 @[widget_module]
@@ -24,37 +21,38 @@ def helloWidget : Widget.Module where
     import * as React from 'react';
     export default function(props) {
       const name = props.name || 'world'
-      return React.createElement('p', {}, 'Hello ' + name + '!')
+      return React.createElement('p', {}, name + '!')
     }"
 
 #widget helloWidget
 
 /-!
 If you want to dive into a full sample right away, check out
-[`Rubiks`](https://github.com/leanprover-community/ProofWidgets4/blob/main/ProofWidgets/Demos/Rubiks.lean).
-This sample uses higher-level widget components from the ProofWidgets library.
-
+[`RubiksCube`](https://github.com/leanprover/lean4-samples/blob/main/RubiksCube/).
 Below, we'll explain the system piece by piece.
 
 ⚠️ WARNING: All of the user widget APIs are **unstable** and subject to breaking changes.
 
-## Widget modules and instances
+## Widget sources and instances
 
-A [widget module](https://leanprover-community.github.io/mathlib4_docs/Lean/Widget/UserWidget.html#Lean.Widget.Module)
-is a valid JavaScript [ESModule](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules)
-that can execute in the Lean infoview.
-Most widget modules export a [React component](https://reactjs.org/docs/components-and-props.html)
-as the piece of user interface to be rendered.
-To access React, the module can use `import * as React from 'react'`.
-Our first example of a widget module is `helloWidget` above.
-Widget modules must be registered with the `@[widget_module]` attribute.
+A *widget source* is a valid JavaScript [ESModule](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules)
+which exports a [React component](https://reactjs.org/docs/components-and-props.html). To access
+React, the module must use `import * as React from 'react'`. Our first example of a widget source
+is of course the value of `helloWidget.javascript`.
 
-A [widget instance](https://leanprover-community.github.io/mathlib4_docs/Lean/Widget/Types.html#Lean.Widget.WidgetInstance)
-is then the identifier of a widget module (e.g. `` `helloWidget ``)
-bundled with a value for its props.
-This value is passed as the argument to the React component.
-In our first invocation of `#widget`, we set it to `.null`.
-Try out what happens when you type in:
+We can register a widget source with the `@[widget]` attribute, giving it a friendlier name
+in the `name` field. This is bundled together in a `UserWidgetDefinition`.
+
+A *widget instance* is then the identifier of a `UserWidgetDefinition` (so `` `helloWidget ``,
+not `"Hello"`) associated with a range of positions in the Lean source code. Widget instances
+are stored in the *infotree* in the same manner as other information about the source file
+such as the type of every expression. In our example, the `#widget` command stores a widget instance
+with the entire line as its range. We can think of a widget instance as an instruction for the
+infoview: "when the user places their cursor here, please render the following widget".
+
+Every widget instance also contains a `props : Json` value. This value is passed as an argument
+to the React component. In our first invocation of `#widget`, we set it to `.null`. Try out what
+happens when you type in:
 -/
 
 structure HelloWidgetProps where
@@ -64,37 +62,21 @@ structure HelloWidgetProps where
 #widget helloWidget with { name? := "<your name here>" : HelloWidgetProps }
 
 /-!
-Under the hood, widget instances are associated with a range of positions in the source file.
-Widget instances are stored in the *infotree*
-in the same manner as other information about the source file
-such as the type of every expression.
-In our example, the `#widget` command stores a widget instance
-with the entire line as its range.
-One can think of the infotree entry as an instruction for the infoview:
-"when the user places their cursor here, please render the following widget".
--/
+💡 NOTE: The RPC system presented below does not depend on JavaScript. However the primary use case
+is the web-based infoview in VSCode.
 
-/-!
 ## Querying the Lean server
 
-💡 NOTE: The RPC system presented below does not depend on JavaScript.
-However, the primary use case is the web-based infoview in VSCode.
+Besides enabling us to create cool client-side visualizations, user widgets come with the ability
+to communicate with the Lean server. Thanks to this, they have the same metaprogramming capabilities
+as custom elaborators or the tactic framework. To see this in action, let's implement a `#check`
+command as a web input form. This example assumes some familiarity with React.
 
-Besides enabling us to create cool client-side visualizations,
-user widgets have the ability to communicate with the Lean server.
-Thanks to this, they have the same metaprogramming capabilities
-as custom elaborators or the tactic framework.
-To see this in action, let's implement a `#check` command as a web input form.
-This example assumes some familiarity with React.
-
-The first thing we'll need is to create an *RPC method*.
-Meaning "Remote Procedure Call",this is a Lean function callable from widget code
-(possibly remotely over the internet).
+The first thing we'll need is to create an *RPC method*. Meaning "Remote Procedure Call", this
+is basically a Lean function callable from widget code (possibly remotely over the internet).
 Our method will take in the `name : Name` of a constant in the environment and return its type.
-By convention, we represent the input data as a `structure`.
-Since it will be sent over from JavaScript,
-we need `FromJson` and `ToJson` instance.
-We'll see why the position field is needed later.
+By convention, we represent the input data as a `structure`. Since it will be sent over from JavaScript,
+we need `FromJson` and `ToJson`. We'll see below why the position field is needed.
 -/
 
 structure GetTypeParams where
@@ -105,33 +87,25 @@ structure GetTypeParams where
   deriving FromJson, ToJson
 
 /-!
-After its argument structure, we define the `getType` method.
-RPCs method execute in the `RequestM` monad and must return a `RequestTask α`
-where `α` is the "actual" return type.
-The `Task` is so that requests can be handled concurrently.
-As a first guess, we'd use `Expr` as `α`.
-However, expressions in general can be large objects
-which depend on an `Environment` and `LocalContext`.
-Thus we cannot directly serialize an `Expr` and send it to JavaScript.
-Instead, there are two options:
+After its arguments, we define the `getType` method. Every RPC method executes in the `RequestM`
+monad and must return a `RequestTask α` where `α` is its "actual" return type. The `Task` is so
+that requests can be handled concurrently. A first guess for `α` might be `Expr`. However,
+expressions in general can be large objects which depend on an `Environment` and `LocalContext`.
+Thus we cannot directly serialize an `Expr` and send it to the widget. Instead, there are two
+options:
+- One is to send a *reference* which points to an object residing on the server. From JavaScript's
+  point of view, references are entirely opaque, but they can be sent back to other RPC methods for
+  further processing.
+- Two is to pretty-print the expression and send its textual representation called `CodeWithInfos`.
+  This representation contains extra data which the infoview uses for interactivity. We take this
+  strategy here.
 
-- One is to send a *reference* which points to an object residing on the server.
-  From JavaScript's point of view, references are entirely opaque,
-  but they can be sent back to other RPC methods for further processing.
-- The other is to pretty-print the expression and send its textual representation called `CodeWithInfos`.
-  This representation contains extra data which the infoview uses for interactivity.
-  We take this strategy here.
-
-RPC methods execute in the context of a file,
-but not of any particular `Environment`,
-so they don't know about the available `def`initions and `theorem`s.
-Thus, we need to pass in a position at which we want to use the local `Environment`.
-This is why we store it in `GetTypeParams`.
-The `withWaitFindSnapAtPos` method launches a concurrent computation
-whose job is to find such an `Environment` for us,
-in the form of a `snap : Snapshot`.
-With this in hand, we can call `MetaM` procedures
-to find out the type of `name` and pretty-print it.
+RPC methods execute in the context of a file, but not any particular `Environment` so they don't
+know about the available `def`initions and `theorem`s. Thus, we need to pass in a position at which
+we want to use the local `Environment`. This is why we store it in `GetTypeParams`. The `withWaitFindSnapAtPos`
+method launches a concurrent computation whose job is to find such an `Environment` and a bit
+more information for us, in the form of a `snap : Snapshot`. With this in hand, we can call
+`MetaM` procedures to find out the type of `name` and pretty-print it.
 -/
 
 open Server RequestM in
@@ -147,22 +121,18 @@ def getType (params : GetTypeParams) : RequestM (RequestTask CodeWithInfos) :=
 /-!
 ## Using infoview components
 
-Now that we have all we need on the server side, let's write the widget module.
-By importing `@leanprover/infoview`, widgets can render UI components used to implement the infoview itself.
-For example, the `<InteractiveCode>` component displays expressions
-with `term : type` tooltips as seen in the goal view.
-We will use it to implement our custom `#check` display.
+Now that we have all we need on the server side, let's write the widget source. By importing
+`@leanprover/infoview`, widgets can render UI components used to implement the infoview itself.
+For example, the `<InteractiveCode>` component displays expressions with `term : type` tooltips
+as seen in the goal view. We will use it to implement our custom `#check` display.
 
 ⚠️ WARNING: Like the other widget APIs, the infoview JS API is **unstable** and subject to breaking changes.
 
-The code below demonstrates useful parts of the API.
-To make RPC method calls, we invoke the `useRpcSession` hook.
-The `useAsync` helper packs the results of an RPC call into an `AsyncState` structure
-which indicates whether the call has resolved successfully,
-has returned an error, or is still in-flight.
-Based on this we either display an `InteractiveCode` component with the result,
-`mapRpcError` the error in order to turn it into a readable message,
-or show a `Loading..` message, respectively.
+The code below demonstrates useful parts of the API. To make RPC method calls, we use the `RpcContext`.
+The `useAsync` helper packs the results of a call into an `AsyncState` structure which indicates
+whether the call has resolved successfully, has returned an error, or is still in-flight. Based
+on this we either display an `InteractiveCode` with the type, `mapRpcError` the error in order
+to turn it into a readable message, or show a `Loading..` message, respectively.
 -/
 
 @[widget_module]
@@ -170,10 +140,10 @@ def checkWidget : Widget.Module where
   javascript := "
 import * as React from 'react';
 const e = React.createElement;
-import { useRpcSession, InteractiveCode, useAsync, mapRpcError } from '@leanprover/infoview';
+import { RpcContext, InteractiveCode, useAsync, mapRpcError } from '@leanprover/infoview';
 
 export default function(props) {
-  const rs = useRpcSession()
+  const rs = React.useContext(RpcContext)
   const [name, setName] = React.useState('getType')
 
   const st = useAsync(() =>
@@ -189,7 +159,7 @@ export default function(props) {
 "
 
 /-!
-We can now try out the widget.
+Finally we can try out the widget.
 -/
 
 #widget checkWidget
@@ -199,31 +169,30 @@ We can now try out the widget.
 
 ## Building widget sources
 
-While typing JavaScript inline is fine for a simple example,
-for real developments we want to use packages from NPM, a proper build system, and JSX.
-Thus, most actual widget sources are built with Lake and NPM.
-They consist of multiple files and may import libraries which don't work as ESModules by default.
-On the other hand a widget module must be a single, self-contained ESModule in the form of a string.
-Readers familiar with web development may already have guessed that to obtain such a string, we need a *bundler*.
-Two popular choices are [`rollup.js`](https://rollupjs.org/guide/en/)
-and [`esbuild`](https://esbuild.github.io/).
-If we go with `rollup.js`, to make a widget work with the infoview we need to:
+While typing JavaScript inline is fine for a simple example, for real developments we want to use
+packages from NPM, a proper build system, and JSX. Thus, most actual widget sources are built with
+Lake and NPM. They consist of multiple files and may import libraries which don't work as ESModules
+by default. On the other hand a widget source must be a single, self-contained ESModule in the form
+of a string. Readers familiar with web development may already have guessed that to obtain such a
+string, we need a *bundler*. Two popular choices are [`rollup.js`](https://rollupjs.org/guide/en/)
+and [`esbuild`](https://esbuild.github.io/). If we go with `rollup.js`, to make a widget work with
+the infoview we need to:
 - Set [`output.format`](https://rollupjs.org/guide/en/#outputformat) to `'es'`.
 - [Externalize](https://rollupjs.org/guide/en/#external) `react`, `react-dom`, `@leanprover/infoview`.
   These libraries are already loaded by the infoview so they should not be bundled.
 
-ProofWidgets provides a working `rollup.js` build configuration in
-[rollup.config.js](https://github.com/leanprover-community/ProofWidgets4/blob/main/widget/rollup.config.js).
+In the RubiksCube sample, we provide a working `rollup.js` build configuration in
+[rollup.config.js](https://github.com/leanprover/lean4-samples/blob/main/RubiksCube/widget/rollup.config.js).
 
 ## Inserting text
 
-Besides making RPC calls, widgets can instruct the editor to carry out certain actions.
-We can insert text, copy text to the clipboard, or highlight a certain location in the document.
-To do this, use the `EditorContext` React context.
-This will return an `EditorConnection`
-whose `api` field contains a number of methods that interact with the editor.
+We can also instruct the editor to insert text, copy text to the clipboard, or
+reveal a certain location in the document.
+To do this, use the `React.useContext(EditorContext)` React context.
+This will return an `EditorConnection` whose `api` field contains a number of methods to
+interact with the text editor.
 
-The full API can be viewed [here](https://github.com/leanprover/vscode-lean4/blob/master/lean4-infoview-api/src/infoviewApi.ts#L52).
+You can see the full API for this [here](https://github.com/leanprover/vscode-lean4/blob/master/lean4-infoview-api/src/infoviewApi.ts#L52)
 -/
 
 @[widget_module]
@@ -243,4 +212,6 @@ export default function(props) {
 }
 "
 
+/-! Finally, we can try this out: -/
+
 #widget insertTextWidget

doc/expressions.md

@@ -396,7 +396,7 @@ Every expression in Lean has a natural computational interpretation, unless it i
 
 * *β-reduction* : An expression ``(λ x, t) s`` β-reduces to ``t[s/x]``, that is, the result of replacing ``x`` by ``s`` in ``t``.
 * *ζ-reduction* : An expression ``let x := s in t`` ζ-reduces to ``t[s/x]``.
-* *δ-reduction* : If ``c`` is a defined constant with definition ``t``, then ``c`` δ-reduces to ``t``.
+* *δ-reduction* : If ``c`` is a defined constant with definition ``t``, then ``c`` δ-reduces to to ``t``.
 * *ι-reduction* : When a function defined by recursion on an inductive type is applied to an element given by an explicit constructor, the result ι-reduces to the specified function value, as described in [Inductive Types](inductive.md).
 
 The reduction relation is transitive, which is to say, is ``s`` reduces to ``s'`` and ``t`` reduces to ``t'``, then ``s t`` reduces to ``s' t'``, ``λ x, s`` reduces to ``λ x, s'``, and so on. If ``s`` and ``t`` reduce to a common term, they are said to be *definitionally equal*. Definitional equality is defined to be the smallest equivalence relation that satisfies all these properties and also includes α-equivalence and the following two relations:

doc/flake.lock

@@ -18,15 +18,12 @@
       }
     },
     "flake-utils": {
-      "inputs": {
-        "systems": "systems"
-      },
       "locked": {
-        "lastModified": 1710146030,
-        "narHash": "sha256-SZ5L6eA7HJ/nmkzGG7/ISclqe6oZdOZTNoesiInkXPQ=",
+        "lastModified": 1656928814,
+        "narHash": "sha256-RIFfgBuKz6Hp89yRr7+NR5tzIAbn52h8vT6vXkYjZoM=",
         "owner": "numtide",
         "repo": "flake-utils",
-        "rev": "b1d9ab70662946ef0850d488da1c9019f3a9752a",
+        "rev": "7e2a3b3dfd9af950a856d66b0a7d01e3c18aa249",
         "type": "github"
       },
       "original": {
@@ -38,12 +35,13 @@
     "lean": {
       "inputs": {
         "flake-utils": "flake-utils",
-        "nixpkgs": "nixpkgs",
-        "nixpkgs-old": "nixpkgs-old"
+        "lean4-mode": "lean4-mode",
+        "nix": "nix",
+        "nixpkgs": "nixpkgs_2"
       },
       "locked": {
         "lastModified": 0,
-        "narHash": "sha256-saRAtQ6VautVXKDw1XH35qwP0KEBKTKZbg/TRa4N9Vw=",
+        "narHash": "sha256-YnYbmG0oou1Q/GE4JbMNb8/yqUVXBPIvcdQQJHBqtPk=",
         "path": "../.",
         "type": "path"
       },
@@ -52,6 +50,22 @@
         "type": "path"
       }
     },
+    "lean4-mode": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1659020985,
+        "narHash": "sha256-+dRaXB7uvN/weSZiKcfSKWhcdJVNg9Vg8k0pJkDNjpc=",
+        "owner": "leanprover",
+        "repo": "lean4-mode",
+        "rev": "37d5c99b7b29c80ab78321edd6773200deb0bca6",
+        "type": "github"
+      },
+      "original": {
+        "owner": "leanprover",
+        "repo": "lean4-mode",
+        "type": "github"
+      }
+    },
     "leanInk": {
       "flake": false,
       "locked": {
@@ -69,6 +83,22 @@
         "type": "github"
       }
     },
+    "lowdown-src": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1633514407,
+        "narHash": "sha256-Dw32tiMjdK9t3ETl5fzGrutQTzh2rufgZV4A/BbxuD4=",
+        "owner": "kristapsdz",
+        "repo": "lowdown",
+        "rev": "d2c2b44ff6c27b936ec27358a2653caaef8f73b8",
+        "type": "github"
+      },
+      "original": {
+        "owner": "kristapsdz",
+        "repo": "lowdown",
+        "type": "github"
+      }
+    },
     "mdBook": {
       "flake": false,
       "locked": {
@@ -85,13 +115,65 @@
         "type": "github"
       }
     },
+    "nix": {
+      "inputs": {
+        "lowdown-src": "lowdown-src",
+        "nixpkgs": "nixpkgs",
+        "nixpkgs-regression": "nixpkgs-regression"
+      },
+      "locked": {
+        "lastModified": 1657097207,
+        "narHash": "sha256-SmeGmjWM3fEed3kQjqIAO8VpGmkC2sL1aPE7kKpK650=",
+        "owner": "NixOS",
+        "repo": "nix",
+        "rev": "f6316b49a0c37172bca87ede6ea8144d7d89832f",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "repo": "nix",
+        "type": "github"
+      }
+    },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1710889954,
-        "narHash": "sha256-Pr6F5Pmd7JnNEMHHmspZ0qVqIBVxyZ13ik1pJtm2QXk=",
+        "lastModified": 1653988320,
+        "narHash": "sha256-ZaqFFsSDipZ6KVqriwM34T739+KLYJvNmCWzErjAg7c=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "7872526e9c5332274ea5932a0c3270d6e4724f3b",
+        "rev": "2fa57ed190fd6c7c746319444f34b5917666e5c1",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-22.05-small",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs-regression": {
+      "locked": {
+        "lastModified": 1643052045,
+        "narHash": "sha256-uGJ0VXIhWKGXxkeNnq4TvV3CIOkUJ3PAoLZ3HMzNVMw=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "215d4d0fd80ca5163643b03a33fde804a29cc1e2",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "215d4d0fd80ca5163643b03a33fde804a29cc1e2",
+        "type": "github"
+      }
+    },
+    "nixpkgs_2": {
+      "locked": {
+        "lastModified": 1657208011,
+        "narHash": "sha256-BlIFwopAykvdy1DYayEkj6ZZdkn+cVgPNX98QVLc0jM=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "2770cc0b1e8faa0e20eb2c6aea64c256a706d4f2",
         "type": "github"
       },
       "original": {
@@ -101,23 +183,6 @@
         "type": "github"
       }
     },
-    "nixpkgs-old": {
-      "flake": false,
-      "locked": {
-        "lastModified": 1581379743,
-        "narHash": "sha256-i1XCn9rKuLjvCdu2UeXKzGLF6IuQePQKFt4hEKRU5oc=",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "34c7eb7545d155cc5b6f499b23a7cb1c96ab4d59",
-        "type": "github"
-      },
-      "original": {
-        "owner": "NixOS",
-        "ref": "nixos-19.03",
-        "repo": "nixpkgs",
-        "type": "github"
-      }
-    },
     "root": {
       "inputs": {
         "alectryon": "alectryon",
@@ -129,21 +194,6 @@
         "leanInk": "leanInk",
         "mdBook": "mdBook"
       }
-    },
-    "systems": {
-      "locked": {
-        "lastModified": 1681028828,
-        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
-        "owner": "nix-systems",
-        "repo": "default",
-        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
-        "type": "github"
-      },
-      "original": {
-        "owner": "nix-systems",
-        "repo": "default",
-        "type": "github"
-      }
     }
   },
   "root": "root",

doc/flake.nix

@@ -17,7 +17,7 @@
   };
 
   outputs = inputs@{ self, ... }: inputs.flake-utils.lib.eachDefaultSystem (system:
-    with inputs.lean.packages.${system}.deprecated; with nixpkgs;
+    with inputs.lean.packages.${system}; with nixpkgs;
     let
       doc-src = lib.sourceByRegex ../. ["doc.*" "tests(/lean(/beginEndAsMacro.lean)?)?"];
     in {
@@ -44,6 +44,21 @@
           mdbook build -d $out
         '';
       };
+      # We use a separate derivation instead of `checkPhase` so we can push it but not `doc` to the binary cache
+      test = stdenv.mkDerivation {
+        name ="lean-doc-test";
+        src = doc-src;
+        buildInputs = [ lean-mdbook stage1.Lean.lean-package strace ];
+        patchPhase = ''
+          cd doc
+          patchShebangs test
+        '';
+        buildPhase = ''
+          mdbook test
+          touch $out
+        '';
+        dontInstall = true;
+      };
       leanInk = (buildLeanPackage {
         name = "Main";
         src = inputs.leanInk;

doc/int.md

@@ -13,7 +13,7 @@ Recall that nonnegative numerals are considered to be a `Nat` if there are no ty
 
 The operator `/` for `Int` implements integer division.
 ```lean
-#eval -10 / 4 -- -3
+#eval -10 / 4 -- -2
 ```
 
 Similar to `Nat`, the internal representation of `Int` is optimized. Small integers are

doc/latex/lean4.py

@@ -0,0 +1,100 @@
+# -*- coding: utf-8 -*-
+"""
+    pygments.lexers.theorem
+    ~~~~~~~~~~~~~~~~~~~~~~~
+
+    Lexers for theorem-proving languages.
+
+    :copyright: Copyright 2006-2017 by the Pygments team, see AUTHORS.
+    :license: BSD, see LICENSE for details.
+"""
+
+import re
+
+from pygments.lexer import RegexLexer, default, words
+from pygments.token import Text, Comment, Operator, Keyword, Name, String, \
+    Number, Punctuation, Generic
+
+__all__ = ['Lean4Lexer']
+
+class Lean4Lexer(RegexLexer):
+    """
+    For the `Lean 4 <https://github.com/leanprover/lean4>`_
+    theorem prover.
+
+    .. versionadded:: 2.0
+    """
+    name = 'Lean4'
+    aliases = ['lean4']
+    filenames = ['*.lean']
+    mimetypes = ['text/x-lean']
+
+    flags = re.MULTILINE | re.UNICODE
+
+    keywords1 = (
+        'import', 'abbreviation', 'opaque_hint', 'tactic_hint', 'definition',
+        'renaming', 'inline', 'hiding', 'parameter', 'lemma', 'variable',
+        'theorem', 'axiom', 'inductive', 'structure', 'universe', 'alias',
+        'help', 'options', 'precedence', 'postfix', 'prefix',
+        'infix', 'infixl', 'infixr', 'notation', '#eval',
+        '#check', '#reduce', '#exit', 'coercion', 'end', 'private', 'using', 'namespace',
+        'including', 'instance', 'section', 'context', 'protected', 'expose',
+        'export', 'set_option', 'extends', 'open', 'example',
+        'constant', 'constants', 'print', 'opaque', 'reducible', 'irreducible',
+        'def', 'macro', 'elab', 'syntax', 'macro_rules', 'reduce', 'where',
+        'abbrev', 'noncomputable', 'class', 'attribute', 'synth', 'mutual',
+    )
+
+    keywords2 = (
+        'forall', 'fun', 'Pi', 'obtain', 'from', 'have', 'show', 'assume',
+        'take', 'let', 'if', 'else', 'then', 'by', 'in', 'with', 'begin',
+        'proof', 'qed', 'calc', 'match', 'nomatch', 'do', 'at',
+    )
+
+    keywords3 = (
+        # Sorts
+        'Type', 'Prop', 'Sort',
+    )
+
+    operators = (
+        u'!=', u'#', u'&', u'&&', u'*', u'+', u'-', u'/', u'@', u'!', u'`',
+        u'-.', u'->', u'.', u'..', u'...', u'::', u':>', u';', u';;', u'<',
+        u'<-', u'=', u'==', u'>', u'_', u'|', u'||', u'~', u'=>', u'<=', u'>=',
+        u'/\\', u'\\/', u'∀', u'Π', u'λ', u'↔', u'∧', u'∨', u'≠', u'≤', u'≥',
+        u'¬', u'⁻¹', u'⬝', u'▸', u'→', u'∃', u'ℕ', u'ℤ', u'≈', u'×', u'⌞',
+        u'⌟', u'≡', u'⟨', u'⟩',
+    )
+
+    punctuation = (u'(', u')', u':', u'{', u'}', u'[', u']', u'⦃', u'⦄',
+                   u':=', u',')
+
+    tokens = {
+        'root': [
+            (r'\s+', Text),
+            (r'/-', Comment, 'comment'),
+            (r'--.*?$', Comment.Single),
+            (words(keywords1, prefix=r'\b', suffix=r'\b'), Keyword.Namespace),
+            (words(keywords2, prefix=r'\b', suffix=r'\b'), Keyword),
+            (words(keywords3, prefix=r'\b', suffix=r'\b'), Keyword.Type),
+            (words(operators), Name.Builtin.Pseudo),
+            (words(punctuation), Operator),
+            (u"[A-Za-z_\u03b1-\u03ba\u03bc-\u03fb\u1f00-\u1ffe\u2100-\u214f]"
+             u"[A-Za-z_'\u03b1-\u03ba\u03bc-\u03fb\u1f00-\u1ffe\u2070-\u2079"
+             u"\u207f-\u2089\u2090-\u209c\u2100-\u214f0-9]*", Name),
+            (r'\d+', Number.Integer),
+            (r'"', String.Double, 'string'),
+            (r'[~?][a-z][\w\']*:', Name.Variable)
+        ],
+        'comment': [
+            # Multiline Comments
+            (r'[^/-]', Comment.Multiline),
+            (r'/-', Comment.Multiline, '#push'),
+            (r'-/', Comment.Multiline, '#pop'),
+            (r'[/-]', Comment.Multiline)
+        ],
+        'string': [
+            (r'[^\\"]+', String.Double),
+            (r'\\[n"\\]', String.Escape),
+            ('"', String.Double, '#pop'),
+        ],
+    }

doc/make/index.md

@@ -1,14 +1,9 @@
-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](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
 ------------
 
 - C++14 compatible compiler
 - [CMake](http://www.cmake.org)
 - [GMP (GNU multiprecision library)](http://gmplib.org/)
-- [LibUV](https://libuv.org/)
 
 Platform-Specific Setup
 -----------------------
@@ -22,27 +17,39 @@ Platform-Specific Setup
 Generic Build Instructions
 --------------------------
 
-Setting up a basic parallelized release build:
+Setting up a basic release build:
 
 ```bash
-git clone https://github.com/leanprover/lean4
+git clone https://github.com/leanprover/lean4 --recurse-submodules
 cd lean4
-cmake --preset release
-make -C build/release -j$(nproc || sysctl -n hw.logicalcpu)
+mkdir -p build/release
+cd build/release
+cmake ../..
+make
 ```
-You can replace `$(nproc || sysctl -n hw.logicalcpu)` with the desired parallelism amount.
+
+For regular development, we recommend running
+```bash
+git config submodule.recurse true
+```
+in the checkout so that `--recurse-submodules` doesn't have to be
+specified with `git pull/checkout/...`.
 
 The above commands will compile the Lean library and binaries into the
-`stage1` subfolder; see below for details.
+`stage1` subfolder; see below for details. Add `-j N` for an
+appropriate `N` to `make` for a parallel build.
 
-You should not usually run `cmake --install` after a successful build.
+For example, on an AMD Ryzen 9 `make` takes 00:04:55, whereas `make -j 10`
+takes 00:01:38.  Your results may vary depending on the speed of your hard
+drive.
+
+You should not usually run `make install` after a successful build.
 See [Dev setup using elan](../dev/index.md#dev-setup-using-elan) on how to properly set up your editor to use the correct stage depending on the source directory.
 
 Useful CMake Configuration Settings
 -----------------------------------
 
-Pass these along with the `cmake --preset release` command.
-There are also two alternative presets that combine some of these options you can use instead of `release`: `debug` and `sandebug` (sanitize + debug).
+Pass these along with the `cmake ../..` command.
 
 * `-D CMAKE_BUILD_TYPE=`\
   Select the build type. Valid values are `RELEASE` (default), `DEBUG`,

doc/make/msvc.md

@@ -0,0 +1,39 @@
+# Compiling Lean with Visual Studio
+
+WARNING: Compiling Lean with Visual Studio doesn't currently work.
+There's an ongoing effort to port Lean to Visual Studio.
+The instructions below are for VS 2017.
+
+In the meantime you can use [MSYS2](msys2.md) or [WSL](wsl.md).
+
+## Installing dependencies
+
+First, install `vcpkg` from https://github.com/Microsoft/vcpkg if you haven't
+done so already.
+Then, open a console in the directory you cloned `vcpkg` to, and type:
+`vcpkg install mpir` for the 32-bit library or
+`vcpkg install mpir:x64-windows` for the x64 one.
+
+In Visual Studio, use the "open folder" feature and open the Lean directory.
+Go to the `CMake->Change CMake Settings` menu. File `CMakeSettings.json` opens.
+In each of the targets, add the following snippet (i.e., after every
+`ctestCommandArgs`):
+
+```json
+    "variables": [
+      {
+        "name": "CMAKE_TOOLCHAIN_FILE",
+        "value": "C:\\path\\to\\vcpkg\\scripts\\buildsystems\\vcpkg.cmake"
+      }
+    ]
+```
+
+## Enable Intellisense
+
+In Visual Studio, press Ctrl+Q and type `CppProperties.json` and press Enter.
+Ensure `includePath` variables include `"${workspaceRoot}\\src"`.
+
+
+## Build Lean
+
+Press F7.

doc/make/msys2.md

@@ -25,7 +25,7 @@ MSYS2 has a package management system, [pacman][pacman], which is used in Arch L
 Here are the commands to install all dependencies needed to compile Lean on your machine.
 
 ```bash
-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
+pacman -S make python mingw-w64-x86_64-cmake mingw-w64-x86_64-clang mingw-w64-x86_64-ccache git unzip diffutils binutils
 ```
 
 You should now be able to run these commands:
@@ -38,9 +38,10 @@ cmake --version
 Then follow the [generic build instructions](index.md) in the MSYS2
 MinGW shell, using:
 ```
-cmake --preset release -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++
+cmake ../.. -G "Unix Makefiles"  -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++
 ```
-instead of `cmake --preset release`. This will use the clang compiler instead of gcc, which is required with msys2.
+instead of `cmake ../..`. This ensures that cmake will call `sh` instead of `cmd.exe`
+for script tasks and it will use the clang compiler instead of gcc, which is required.
 
 ## Install lean
 
@@ -64,7 +65,6 @@ they are installed in your MSYS setup:
 - libgcc_s_seh-1.dll
 - libstdc++-6.dll
 - libgmp-10.dll
-- libuv-1.dll
 - libwinpthread-1.dll
 
 The following linux command will do that:

doc/make/osx-10.9.md

@@ -1,4 +1,4 @@
-# Install Packages on OS X 14.5
+# Install Packages on OS X 10.9
 
 We assume that you are using [homebrew][homebrew] as a package manager.
 
@@ -22,7 +22,7 @@ brew install gcc
 ```
 To install clang++-3.5 via homebrew, please execute:
 ```bash
-brew install llvm
+brew install llvm --with-clang --with-asan
 ```
 To use compilers other than the default one (Apple's clang++), you
 need to use `-DCMAKE_CXX_COMPILER` option to specify the compiler
@@ -32,16 +32,15 @@ following to use `g++`.
 cmake -DCMAKE_CXX_COMPILER=g++ ...
 ```
 
-## Required Packages: CMake, GMP, libuv
+## Required Packages: CMake, GMP
 
 ```bash
 brew install cmake
 brew install gmp
-brew install libuv
 ```
 
 ## Recommended Packages: CCache
 
 ```bash
 brew install ccache
-```
+```

doc/make/ubuntu.md

@@ -8,5 +8,5 @@ follow the [generic build instructions](index.md).
 ## Basic packages
 
 ```bash
-sudo apt-get install git libgmp-dev libuv1-dev cmake ccache clang
+sudo apt-get install git libgmp-dev cmake ccache clang
 ```

doc/monads/laws.lean

@@ -171,7 +171,7 @@ of data contained in the container resulting in a new container that has the sam
 
 `u <*> pure y = pure (. y) <*> u`.
 
-This law is a little more complicated, so don't sweat it too much. It states that the order that
+This law is is a little more complicated, so don't sweat it too much. It states that the order that
 you wrap things shouldn't matter. One the left, you apply any applicative `u` over a pure wrapped
 object. On the right, you first wrap a function applying the object as an argument. Note that `(·
 y)` is short hand for: `fun f => f y`. Then you apply this to the first applicative `u`. These

doc/monads/states.lean

@@ -15,7 +15,7 @@ data type containing several important pieces of information. First and foremost
 current player, and it has a random generator.
 -/
 
-open Batteries (HashMap)
+open Std (HashMap)
 abbrev TileIndex := Nat × Nat -- a 2D index
 
 inductive TileState where

doc/quickstart.md

@@ -5,19 +5,14 @@ See [Setup](./setup.md) for supported platforms and other ways to set up Lean 4.
 
 1. Install [VS Code](https://code.visualstudio.com/).
 
-1. Launch VS Code and install the `Lean 4` extension by clicking on the 'Extensions' sidebar entry and searching for 'Lean 4'.
+1. Launch VS Code and install the `lean4` extension by clicking on the "Extensions" sidebar entry and searching for "lean4".
 
-   ![installing the vscode-lean4 extension](images/code-ext.png)
+    ![installing the vscode-lean4 extension](images/code-ext.png)
 
-1. Open the Lean 4 setup guide by creating a new text file using 'File > New Text File' (`Ctrl+N` / `Cmd+N`), clicking on the ∀-symbol in the top right and selecting 'Documentation… > Docs: Show Setup Guide'.
+1. Open the Lean 4 setup guide by creating a new text file using "File > New Text File" (`Ctrl+N`), clicking on the ∀-symbol in the top right and selecting "Documentation… > Setup: Show Setup Guide".
 
-   ![show setup guide](images/show-setup-guide.png)
+    ![show setup guide](images/show-setup-guide.png)
 
-1. Follow the Lean 4 setup guide. It will:
+1. Follow the Lean 4 setup guide. It will walk you through learning resources for Lean 4, teach you how to set up Lean's dependencies on your platform, install Lean 4 for you at the click of a button and help you set up your first project.
 
-   - walk you through learning resources for Lean,
-   - teach you how to set up Lean's dependencies on your platform,
-   - install Lean 4 for you at the click of a button,
-   - help you set up your first project.
-
-   ![setup guide](images/setup_guide.png)
+    ![setup guide](images/setup_guide.png)

doc/setup.md

@@ -6,7 +6,6 @@ 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 10+
 
 ### Tier 2
@@ -17,6 +16,7 @@ Releases may be silently broken due to the lack of automated testing.
 Issue reports and fixes are welcome.
 
 * aarch64 Linux with glibc 2.27+
+* aarch64 (Apple Silicon) macOS
 * x86 (32-bit) Linux
 * Emscripten Web Assembly
 

doc/syntax_highlight_in_latex.md

@@ -43,8 +43,7 @@ $ pdflatex test.tex
 
 ## Example with `minted`
 
-First [install Pygments](https://pygments.org/download/) (version 2.18 or newer).
-Then save the following sample LaTeX file `test.tex` into the same directory:
+First [install Pygments](https://pygments.org/download/). Then save [`lean4.py`](https://raw.githubusercontent.com/leanprover/lean4/master/doc/latex/lean4.py), which contains an version of the Lean highlighter updated for Lean 4, and the following sample LaTeX file `test.tex` into the same directory:
 
 ```latex
 \documentclass{article}
@@ -52,8 +51,9 @@ Then save the following sample LaTeX file `test.tex` into the same directory:
 % switch to a monospace font supporting more Unicode characters
 \setmonofont{FreeMono}
 \usepackage{minted}
-\newmintinline[lean]{lean4}{bgcolor=white}
-\newminted[leancode]{lean4}{fontsize=\footnotesize}
+% instruct minted to use our local theorem.py
+\newmintinline[lean]{lean4.py:Lean4Lexer -x}{bgcolor=white}
+\newminted[leancode]{lean4.py:Lean4Lexer -x}{fontsize=\footnotesize}
 \usemintedstyle{tango}  % a nice, colorful theme
 
 \begin{document}
@@ -67,6 +67,9 @@ theorem funext {f₁ f₂ : ∀ (x : α), β x} (h : ∀ x, f₁ x = f₂ x) : f
 \end{document}
 ```
 
+If your version of `minted` is v2.7 or newer, but before v3.0,
+you will additionally need to follow the workaround described in https://github.com/gpoore/minted/issues/360.
+
 You can then compile `test.tex` by executing the following command:
 
 ```bash
@@ -78,14 +81,11 @@ Some remarks:
  - either `xelatex` or `lualatex` is required to handle Unicode characters in the code.
  - `--shell-escape` is needed to allow `xelatex` to execute `pygmentize` in a shell.
  - If the chosen monospace font is missing some Unicode symbols, you can direct them to be displayed using a fallback font or other replacement LaTeX code.
-   ``` latex
-   \usepackage{newunicodechar}
-   \newfontfamily{\freeserif}{DejaVu Sans}
-   \newunicodechar{✝}{\freeserif{✝}}
-   \newunicodechar{𝓞}{\ensuremath{\mathcal{O}}}
-   ```
- - If you are using an old version of Pygments, you can copy 
-   [`lean.py`](https://raw.githubusercontent.com/pygments/pygments/master/pygments/lexers/lean.py) into your working directory,
-   and use `lean4.py:Lean4Lexer -x` instead of `lean4` above.
-   If your version of `minted` is v2.7 or newer, but before v3.0,
-   you will additionally need to follow the workaround described in https://github.com/gpoore/minted/issues/360.
+``` latex
+\usepackage{newunicodechar}
+\newfontfamily{\freeserif}{DejaVu Sans}
+\newunicodechar{✝}{\freeserif{✝}}
+\newunicodechar{𝓞}{\ensuremath{\mathcal{O}}}
+```
+ - minted has a "helpful" feature that draws red boxes around characters the chosen lexer doesn't recognize.
+ Since the Lean lexer cannot encompass all user-defined syntax, it is advisable to [work around](https://tex.stackexchange.com/a/343506/14563) this feature.

flake.lock

@@ -1,5 +1,21 @@
 {
   "nodes": {
+    "flake-compat": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1673956053,
+        "narHash": "sha256-4gtG9iQuiKITOjNQQeQIpoIB6b16fm+504Ch3sNKLd8=",
+        "owner": "edolstra",
+        "repo": "flake-compat",
+        "rev": "35bb57c0c8d8b62bbfd284272c928ceb64ddbde9",
+        "type": "github"
+      },
+      "original": {
+        "owner": "edolstra",
+        "repo": "flake-compat",
+        "type": "github"
+      }
+    },
     "flake-utils": {
       "inputs": {
         "systems": "systems"
@@ -18,35 +34,72 @@
         "type": "github"
       }
     },
-    "nixpkgs": {
+    "lean4-mode": {
+      "flake": false,
       "locked": {
-        "lastModified": 1710889954,
-        "narHash": "sha256-Pr6F5Pmd7JnNEMHHmspZ0qVqIBVxyZ13ik1pJtm2QXk=",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "7872526e9c5332274ea5932a0c3270d6e4724f3b",
+        "lastModified": 1709737301,
+        "narHash": "sha256-uT9JN2kLNKJK9c/S/WxLjiHmwijq49EgLb+gJUSDpz0=",
+        "owner": "leanprover",
+        "repo": "lean4-mode",
+        "rev": "f1f24c15134dee3754b82c9d9924866fe6bc6b9f",
         "type": "github"
       },
       "original": {
-        "owner": "NixOS",
-        "ref": "nixpkgs-unstable",
-        "repo": "nixpkgs",
+        "owner": "leanprover",
+        "repo": "lean4-mode",
         "type": "github"
       }
     },
-    "nixpkgs-cadical": {
+    "libgit2": {
+      "flake": false,
       "locked": {
-        "lastModified": 1722221733,
-        "narHash": "sha256-sga9SrrPb+pQJxG1ttJfMPheZvDOxApFfwXCFO0H9xw=",
+        "lastModified": 1697646580,
+        "narHash": "sha256-oX4Z3S9WtJlwvj0uH9HlYcWv+x1hqp8mhXl7HsLu2f0=",
+        "owner": "libgit2",
+        "repo": "libgit2",
+        "rev": "45fd9ed7ae1a9b74b957ef4f337bc3c8b3df01b5",
+        "type": "github"
+      },
+      "original": {
+        "owner": "libgit2",
+        "repo": "libgit2",
+        "type": "github"
+      }
+    },
+    "nix": {
+      "inputs": {
+        "flake-compat": "flake-compat",
+        "libgit2": "libgit2",
+        "nixpkgs": "nixpkgs",
+        "nixpkgs-regression": "nixpkgs-regression"
+      },
+      "locked": {
+        "lastModified": 1711102798,
+        "narHash": "sha256-CXOIJr8byjolqG7eqCLa+Wfi7rah62VmLoqSXENaZnw=",
         "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "12bf09802d77264e441f48e25459c10c93eada2e",
+        "repo": "nix",
+        "rev": "a22328066416650471c3545b0b138669ea212ab4",
         "type": "github"
       },
       "original": {
+        "owner": "NixOS",
+        "repo": "nix",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1709083642,
+        "narHash": "sha256-7kkJQd4rZ+vFrzWu8sTRtta5D1kBG0LSRYAfhtmMlSo=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "12bf09802d77264e441f48e25459c10c93eada2e",
+        "rev": "b550fe4b4776908ac2a861124307045f8e717c8e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "release-23.11",
+        "repo": "nixpkgs",
         "type": "github"
       }
     },
@@ -67,11 +120,44 @@
         "type": "github"
       }
     },
+    "nixpkgs-regression": {
+      "locked": {
+        "lastModified": 1643052045,
+        "narHash": "sha256-uGJ0VXIhWKGXxkeNnq4TvV3CIOkUJ3PAoLZ3HMzNVMw=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "215d4d0fd80ca5163643b03a33fde804a29cc1e2",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "215d4d0fd80ca5163643b03a33fde804a29cc1e2",
+        "type": "github"
+      }
+    },
+    "nixpkgs_2": {
+      "locked": {
+        "lastModified": 1710889954,
+        "narHash": "sha256-Pr6F5Pmd7JnNEMHHmspZ0qVqIBVxyZ13ik1pJtm2QXk=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "7872526e9c5332274ea5932a0c3270d6e4724f3b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
     "root": {
       "inputs": {
         "flake-utils": "flake-utils",
-        "nixpkgs": "nixpkgs",
-        "nixpkgs-cadical": "nixpkgs-cadical",
+        "lean4-mode": "lean4-mode",
+        "nix": "nix",
+        "nixpkgs": "nixpkgs_2",
         "nixpkgs-old": "nixpkgs-old"
       }
     },

flake.nix

@@ -1,61 +1,96 @@
 {
-  description = "Lean development flake. Not intended for end users.";
+  description = "Lean interactive theorem prover";
 
   inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
   # old nixpkgs used for portable release with older glibc (2.27)
   inputs.nixpkgs-old.url = "github:NixOS/nixpkgs/nixos-19.03";
   inputs.nixpkgs-old.flake = false;
-  # for cadical 1.9.5; sync with CMakeLists.txt
-  inputs.nixpkgs-cadical.url = "github:NixOS/nixpkgs/12bf09802d77264e441f48e25459c10c93eada2e";
   inputs.flake-utils.url = "github:numtide/flake-utils";
+  inputs.nix.url = "github:NixOS/nix";
+  inputs.lean4-mode = {
+    url = "github:leanprover/lean4-mode";
+    flake = false;
+  };
+  # used *only* by `stage0-from-input` below
+  #inputs.lean-stage0 = {
+  #  url = github:leanprover/lean4;
+  #  inputs.nixpkgs.follows = "nixpkgs";
+  #  inputs.flake-utils.follows = "flake-utils";
+  #  inputs.nix.follows = "nix";
+  #  inputs.lean4-mode.follows = "lean4-mode";
+  #};
 
-  outputs = { self, nixpkgs, nixpkgs-old, flake-utils, ... }@inputs: flake-utils.lib.eachDefaultSystem (system:
+  outputs = { self, nixpkgs, nixpkgs-old, flake-utils, nix, lean4-mode, ... }@inputs: flake-utils.lib.eachDefaultSystem (system:
     let
-      pkgs = import nixpkgs { inherit system; };
+      pkgs = import nixpkgs {
+        inherit system;
+        # for `vscode-with-extensions`
+        config.allowUnfree = true;
+      };
       # An old nixpkgs for creating releases with an old glibc
       pkgsDist-old = import nixpkgs-old { inherit system; };
       # An old nixpkgs for creating releases with an old glibc
       pkgsDist-old-aarch = import nixpkgs-old { localSystem.config = "aarch64-unknown-linux-gnu"; };
-      pkgsCadical = import inputs.nixpkgs-cadical { inherit system; };
-      cadical = if pkgs.stdenv.isLinux then
-        # use statically-linked cadical on Linux to avoid glibc versioning troubles
-        pkgsCadical.pkgsStatic.cadical.overrideAttrs { doCheck = false; }
-      else pkgsCadical.cadical;
 
-      lean-packages = pkgs.callPackage (./nix/packages.nix) { src = ./.; };
+      lean-packages = pkgs.callPackage (./nix/packages.nix) { src = ./.; inherit nix lean4-mode; };
 
       devShellWithDist = pkgsDist: pkgs.mkShell.override {
-          stdenv = pkgs.overrideCC pkgs.stdenv lean-packages.llvmPackages.clang;
-        } ({
-          buildInputs = with pkgs; [
-            cmake gmp libuv ccache cadical
-            lean-packages.llvmPackages.llvm  # llvm-symbolizer for asan/lsan
-            gdb
-            tree  # for CI
-          ];
-          # https://github.com/NixOS/nixpkgs/issues/60919
-          hardeningDisable = [ "all" ];
-          # more convenient `ctest` output
-          CTEST_OUTPUT_ON_FAILURE = 1;
-        } // pkgs.lib.optionalAttrs pkgs.stdenv.isLinux {
-          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;
-          ZLIB = pkgsDist.zlib;
-          GDB = pkgsDist.gdb;
-        });
+	  stdenv = pkgs.overrideCC pkgs.stdenv lean-packages.llvmPackages.clang;
+	} ({
+	  buildInputs = with pkgs; [
+	    cmake gmp ccache
+	    lean-packages.llvmPackages.llvm  # llvm-symbolizer for asan/lsan
+	    # TODO: only add when proven to not affect the flakification
+	    #pkgs.python3
+	  ];
+	  # https://github.com/NixOS/nixpkgs/issues/60919
+	  hardeningDisable = [ "all" ];
+	  # more convenient `ctest` output
+	  CTEST_OUTPUT_ON_FAILURE = 1;
+	} // pkgs.lib.optionalAttrs pkgs.stdenv.isLinux {
+	  GMP = pkgsDist.gmp.override { withStatic = true; };
+	  GLIBC = pkgsDist.glibc;
+	  GLIBC_DEV = pkgsDist.glibc.dev;
+	  GCC_LIB = pkgsDist.gcc.cc.lib;
+	  ZLIB = pkgsDist.zlib;
+	  GDB = pkgsDist.gdb;
+	});
     in {
-      packages = {
-        # to be removed when Nix CI is not needed anymore
-        inherit (lean-packages) cacheRoots test update-stage0-commit ciShell;
-        deprecated = lean-packages;
+      packages = lean-packages // rec {
+        debug = lean-packages.override { debug = true; };
+        stage0debug = lean-packages.override { stage0debug = true; };
+        asan = lean-packages.override { extraCMakeFlags = [ "-DLEAN_EXTRA_CXX_FLAGS=-fsanitize=address" "-DLEANC_EXTRA_FLAGS=-fsanitize=address" "-DSMALL_ALLOCATOR=OFF" "-DSYMBOLIC=OFF" ]; };
+        asandebug = asan.override { debug = true; };
+        tsan = lean-packages.override {
+          extraCMakeFlags = [ "-DLEAN_EXTRA_CXX_FLAGS=-fsanitize=thread" "-DLEANC_EXTRA_FLAGS=-fsanitize=thread" "-DCOMPRESSED_OBJECT_HEADER=OFF" ];
+          stage0 = (lean-packages.override {
+            # Compressed headers currently trigger data race reports in tsan.
+            # Turn them off for stage 0 as well so stage 1 can read its own stdlib.
+            extraCMakeFlags = [ "-DCOMPRESSED_OBJECT_HEADER=OFF" ];
+          }).stage1;
+        };
+        tsandebug = tsan.override { debug = true; };
+        stage0-from-input = lean-packages.override {
+          stage0 = pkgs.writeShellScriptBin "lean" ''
+            exec ${inputs.lean-stage0.packages.${system}.lean}/bin/lean -Dinterpreter.prefer_native=false "$@"
+          '';
+        };
+        inherit self;
       };
+      defaultPackage = lean-packages.lean-all;
 
       # The default development shell for working on lean itself
       devShells.default = devShellWithDist pkgs;
       devShells.oldGlibc = devShellWithDist pkgsDist-old;
       devShells.oldGlibcAArch = devShellWithDist pkgsDist-old-aarch;
-    });
+
+      checks.lean = lean-packages.test;
+    }) // rec {
+      templates.pkg = {
+        path = ./nix/templates/pkg;
+        description = "A custom Lean package";
+      };
+
+      defaultTemplate = templates.pkg;
+    };
 }

nix/bootstrap.nix

@@ -1,13 +1,13 @@
 { src, debug ? false, stage0debug ? false, extraCMakeFlags ? [],
-  stdenv, lib, cmake, gmp, libuv, cadical, git, gnumake, bash, buildLeanPackage, writeShellScriptBin, runCommand, symlinkJoin, lndir, perl, gnused, darwin, llvmPackages, linkFarmFromDrvs,
+  stdenv, lib, cmake, gmp, git, gnumake, bash, buildLeanPackage, writeShellScriptBin, runCommand, symlinkJoin, lndir, perl, gnused, darwin, llvmPackages, linkFarmFromDrvs,
   ... } @ args:
 with builtins;
-lib.warn "The Nix-based build is deprecated" rec {
+rec {
   inherit stdenv;
   sourceByRegex = p: rs: lib.sourceByRegex p (map (r: "(/src/)?${r}") rs);
   buildCMake = args: stdenv.mkDerivation ({
     nativeBuildInputs = [ cmake ];
-    buildInputs = [ gmp libuv llvmPackages.llvm ];
+    buildInputs = [ gmp llvmPackages.llvm ];
     # https://github.com/NixOS/nixpkgs/issues/60919
     hardeningDisable = [ "all" ];
     dontStrip = (args.debug or debug);
@@ -17,7 +17,7 @@ lib.warn "The Nix-based build is deprecated" rec {
     '';
   } // args // {
     src = args.realSrc or (sourceByRegex args.src [ "[a-z].*" "CMakeLists\.txt" ]);
-    cmakeFlags = (args.cmakeFlags or [ "-DSTAGE=1" "-DPREV_STAGE=./faux-prev-stage" "-DUSE_GITHASH=OFF" "-DCADICAL=${cadical}/bin/cadical" ]) ++ (args.extraCMakeFlags or extraCMakeFlags) ++ lib.optional (args.debug or debug) [ "-DCMAKE_BUILD_TYPE=Debug" ];
+    cmakeFlags = (args.cmakeFlags or [ "-DSTAGE=1" "-DPREV_STAGE=./faux-prev-stage" "-DUSE_GITHASH=OFF" ]) ++ (args.extraCMakeFlags or extraCMakeFlags) ++ lib.optional (args.debug or debug) [ "-DCMAKE_BUILD_TYPE=Debug" ];
     preConfigure = args.preConfigure or "" + ''
       # ignore absence of submodule
       sed -i 's!lake/Lake.lean!!' CMakeLists.txt
@@ -26,7 +26,11 @@ lib.warn "The Nix-based build is deprecated" rec {
   lean-bin-tools-unwrapped = buildCMake {
     name = "lean-bin-tools";
     outputs = [ "out" "leanc_src" ];
-    realSrc = sourceByRegex (src + "/src") [ "CMakeLists\.txt" "[a-z].*" ".*\.in" "Leanc\.lean" ];
+    realSrc = sourceByRegex (src + "/src") [ "CMakeLists\.txt" "cmake.*" "bin.*" "include.*" ".*\.in" "Leanc\.lean" ];
+    preConfigure = ''
+      touch empty.cpp
+      sed -i 's/add_subdirectory.*//;s/set(LEAN_OBJS.*/set(LEAN_OBJS empty.cpp)/' CMakeLists.txt
+    '';
     dontBuild = true;
     installPhase = ''
       mkdir $out $leanc_src
@@ -41,10 +45,11 @@ lib.warn "The Nix-based build is deprecated" rec {
   leancpp = buildCMake {
     name = "leancpp";
     src = src + "/src";
-    buildFlags = [ "leancpp" "leanrt" "leanrt_initial-exec" "leanshell" "leanmain" ];
+    buildFlags = [ "leancpp" "leanrt" "leanrt_initial-exec" "shell" ];
     installPhase = ''
       mkdir -p $out
       mv lib/ $out/
+      mv shell/CMakeFiles/shell.dir/lean.cpp.o $out/lib
       mv runtime/libleanrt_initial-exec.a $out/lib
     '';
   };
@@ -82,8 +87,7 @@ lib.warn "The Nix-based build is deprecated" rec {
         leanFlags = [ "-DwarningAsError=true" ];
       } // args);
       Init' = build { name = "Init"; deps = []; };
-      Std' = build { name = "Std"; deps = [ Init' ]; };
-      Lean' = build { name = "Lean"; deps = [ Std' ]; };
+      Lean' = build { name = "Lean"; deps = [ Init' ]; };
       attachSharedLib = sharedLib: pkg: pkg // {
         inherit sharedLib;
         mods = mapAttrs (_: m: m // { inherit sharedLib; propagatedLoadDynlibs = []; }) pkg.mods;
@@ -91,61 +95,55 @@ lib.warn "The Nix-based build is deprecated" rec {
     in (all: all // all.lean) rec {
       inherit (Lean) emacs-dev emacs-package vscode-dev vscode-package;
       Init = attachSharedLib leanshared Init';
-      Std = attachSharedLib leanshared Std' // { allExternalDeps = [ Init ]; };
-      Lean = attachSharedLib leanshared Lean' // { allExternalDeps = [ Std ]; };
+      Lean = attachSharedLib leanshared Lean' // { allExternalDeps = [ Init ]; };
       Lake = build {
         name = "Lake";
-        sharedLibName = "Lake_shared";
         src = src + "/src/lake";
         deps = [ Init Lean ];
       };
       Lake-Main = build {
-        name = "LakeMain";
-        roots = [{ glob = "one"; mod = "LakeMain"; }];
+        name = "Lake.Main";
+        roots = [ "Lake.Main" ];
         executableName = "lake";
         deps = [ Lake ];
         linkFlags = lib.optional stdenv.isLinux "-rdynamic";
         src = src + "/src/lake";
       };
-      stdlib = [ Init Std Lean Lake ];
+      stdlib = [ Init Lean Lake ];
       modDepsFiles = symlinkJoin { name = "modDepsFiles"; paths = map (l: l.modDepsFile) (stdlib ++ [ Leanc ]); };
       depRoots = symlinkJoin { name = "depRoots"; paths = map (l: l.depRoots) stdlib; };
       iTree = symlinkJoin { name = "ileans"; paths = map (l: l.iTree) stdlib; };
       Leanc = build { name = "Leanc"; src = lean-bin-tools-unwrapped.leanc_src; deps = stdlib; roots = [ "Leanc" ]; };
-      stdlibLinkFlags = "${lib.concatMapStringsSep " " (l: "-L${l.staticLib}") stdlib} -L${leancpp}/lib/lean";
+      stdlibLinkFlags = "-L${Init.staticLib} -L${Lean.staticLib} -L${Lake.staticLib} -L${leancpp}/lib/lean";
       libInit_shared = runCommand "libInit_shared" { buildInputs = [ stdenv.cc ]; libName = "libInit_shared${stdenv.hostPlatform.extensions.sharedLibrary}"; } ''
         mkdir $out
-        touch empty.c
-        ${stdenv.cc}/bin/cc -shared -o $out/$libName empty.c
-      '';
-      leanshared_1 = runCommand "leanshared_1" { buildInputs = [ stdenv.cc ]; libName = "leanshared_1${stdenv.hostPlatform.extensions.sharedLibrary}"; } ''
-        mkdir $out
-        touch empty.c
-        ${stdenv.cc}/bin/cc -shared -o $out/$libName empty.c
+        LEAN_CC=${stdenv.cc}/bin/cc ${lean-bin-tools-unwrapped}/bin/leanc -shared -Wl,-Bsymbolic \
+          -Wl,--whole-archive -lInit ${leancpp}/lib/libleanrt_initial-exec.a -Wl,--no-whole-archive -lstdc++ -lm ${stdlibLinkFlags} \
+          $(${llvmPackages.libllvm.dev}/bin/llvm-config --ldflags --libs) \
+          -o $out/$libName
       '';
       leanshared = runCommand "leanshared" { buildInputs = [ stdenv.cc ]; libName = "libleanshared${stdenv.hostPlatform.extensions.sharedLibrary}"; } ''
         mkdir $out
-        LEAN_CC=${stdenv.cc}/bin/cc ${lean-bin-tools-unwrapped}/bin/leanc -shared ${lib.optionalString stdenv.isLinux "-Wl,-Bsymbolic"} \
-          -Wl,--whole-archive ${leancpp}/lib/temp/libleanshell.a -lInit -lStd -lLean -lleancpp ${leancpp}/lib/libleanrt_initial-exec.a -Wl,--no-whole-archive -lstdc++ \
-          -lm ${stdlibLinkFlags} \
+        LEAN_CC=${stdenv.cc}/bin/cc ${lean-bin-tools-unwrapped}/bin/leanc -shared -Wl,-Bsymbolic \
+          ${libInit_shared}/* -Wl,--whole-archive -lLean -lleancpp -Wl,--no-whole-archive -lstdc++ -lm ${stdlibLinkFlags} \
           $(${llvmPackages.libllvm.dev}/bin/llvm-config --ldflags --libs) \
           -o $out/$libName
       '';
       mods = foldl' (mods: pkg: mods // pkg.mods) {} stdlib;
       print-paths = Lean.makePrintPathsFor [] mods;
       leanc = writeShellScriptBin "leanc" ''
-        LEAN_CC=${stdenv.cc}/bin/cc ${Leanc.executable}/bin/leanc -I${lean-bin-tools-unwrapped}/include ${stdlibLinkFlags} -L${libInit_shared} -L${leanshared_1} -L${leanshared} -L${Lake.sharedLib} "$@"
+        LEAN_CC=${stdenv.cc}/bin/cc ${Leanc.executable}/bin/leanc -I${lean-bin-tools-unwrapped}/include ${stdlibLinkFlags} -L${libInit_shared} -L${leanshared} "$@"
       '';
       lean = runCommand "lean" { buildInputs = lib.optional stdenv.isDarwin darwin.cctools; } ''
         mkdir -p $out/bin
-        ${leanc}/bin/leanc ${leancpp}/lib/temp/libleanmain.a ${libInit_shared}/* ${leanshared_1}/* ${leanshared}/* -o $out/bin/lean
+        ${leanc}/bin/leanc ${leancpp}/lib/lean.cpp.o ${libInit_shared}/* ${leanshared}/* -o $out/bin/lean
       '';
       # derivation following the directory layout of the "basic" setup, mostly useful for running tests
       lean-all = stdenv.mkDerivation {
         name = "lean-${desc}";
         buildCommand = ''
           mkdir -p $out/bin $out/lib/lean
-          ln -sf ${leancpp}/lib/lean/* ${lib.concatMapStringsSep " " (l: "${l.modRoot}/* ${l.staticLib}/*") (lib.reverseList stdlib)} ${libInit_shared}/* ${leanshared_1}/* ${leanshared}/* ${Lake.sharedLib}/* $out/lib/lean/
+          ln -sf ${leancpp}/lib/lean/* ${lib.concatMapStringsSep " " (l: "${l.modRoot}/* ${l.staticLib}/*") (lib.reverseList stdlib)} ${libInit_shared}/* ${leanshared}/* $out/lib/lean/
           # put everything in a single final derivation so `IO.appDir` references work
           cp ${lean}/bin/lean ${leanc}/bin/leanc ${Lake-Main.executable}/bin/lake $out/bin
           # NOTE: `lndir` will not override existing `bin/leanc`
@@ -153,13 +151,15 @@ lib.warn "The Nix-based build is deprecated" rec {
         '';
         meta.mainProgram = "lean";
       };
-      cacheRoots = linkFarmFromDrvs "cacheRoots" ([
+      cacheRoots = linkFarmFromDrvs "cacheRoots" [
         stage0 lean leanc lean-all iTree modDepsFiles depRoots Leanc.src
-      ] ++ map (lib: lib.oTree) stdlib);
+        # .o files are not a runtime dependency on macOS because of lack of thin archives
+        Lean.oTree Lake.oTree
+      ];
       test = buildCMake {
         name = "lean-test-${desc}";
         realSrc = lib.sourceByRegex src [ "src.*" "tests.*" ];
-        buildInputs = [ gmp libuv perl git cadical ];
+        buildInputs = [ gmp perl git ];
         preConfigure = ''
           cd src
         '';
@@ -170,7 +170,7 @@ lib.warn "The Nix-based build is deprecated" rec {
           ln -sf ${lean-all}/* .
         '';
         buildPhase = ''
-          ctest --output-junit test-results.xml --output-on-failure -E 'leancomptest_(doc_example|foreign)|leanlaketest_reverse-ffi' -j$NIX_BUILD_CORES
+          ctest --output-junit test-results.xml --output-on-failure -E 'leancomptest_(doc_example|foreign)' -j$NIX_BUILD_CORES
         '';
         installPhase = ''
           mkdir $out
@@ -178,9 +178,9 @@ lib.warn "The Nix-based build is deprecated" rec {
         '';
       };
       update-stage0 =
-        let cTree = symlinkJoin { name = "cs"; paths = map (lib: lib.cTree) (stdlib ++ [Lake-Main]); }; in
+        let cTree = symlinkJoin { name = "cs"; paths = [ Init.cTree Lean.cTree ]; }; in
         writeShellScriptBin "update-stage0" ''
-          CSRCS=${cTree} CP_C_PARAMS="--dereference --no-preserve=all" ${src + "/script/lib/update-stage0"}
+          CSRCS=${cTree} CP_C_PARAMS="--dereference --no-preserve=all" ${src + "/script/update-stage0"}
         '';
       update-stage0-commit = writeShellScriptBin "update-stage0-commit" ''
         set -euo pipefail

nix/buildLeanPackage.nix

@@ -1,11 +1,11 @@
 { lean, lean-leanDeps ? lean, lean-final ? lean, leanc,
-  stdenv, lib, coreutils, gnused, writeShellScriptBin, bash, substituteAll, symlinkJoin, linkFarmFromDrvs,
+  stdenv, lib, coreutils, gnused, writeShellScriptBin, bash, lean-emacs, lean-vscode, nix, substituteAll, symlinkJoin, linkFarmFromDrvs,
   runCommand, darwin, mkShell, ... }:
 let lean-final' = lean-final; in
 lib.makeOverridable (
 { name, src, fullSrc ? src, srcPrefix ? "", srcPath ? "$PWD/${srcPrefix}",
   # Lean dependencies. Each entry should be an output of buildLeanPackage.
-  deps ? [ lean.Init lean.Std lean.Lean ],
+  deps ? [ lean.Lean ],
   # Static library dependencies. Each derivation `static` should contain a static library in the directory `${static}`.
   staticLibDeps ? [],
   # Whether to wrap static library inputs in a -Wl,--start-group [...] -Wl,--end-group to ensure dependencies are resolved.
@@ -30,7 +30,7 @@ lib.makeOverridable (
   pluginDeps ? [],
   # `overrideAttrs` for `buildMod`
   overrideBuildModAttrs ? null,
-  debug ? false, leanFlags ? [], leancFlags ? [], linkFlags ? [], executableName ? lib.toLower name, libName ? name, sharedLibName ? libName,
+  debug ? false, leanFlags ? [], leancFlags ? [], linkFlags ? [], executableName ? lib.toLower name, libName ? name,
   srcTarget ? "..#stage0", srcArgs ? "(\${args[*]})", lean-final ? lean-final' }@args:
 with builtins; let
   # "Init.Core" ~> "Init/Core"
@@ -197,6 +197,19 @@ with builtins; let
              then map (m: m.module) header.imports
              else abort "errors while parsing imports of ${mod}:\n${lib.concatStringsSep "\n" header.errors}";
     in mkMod mod (map (dep: if modDepsMap ? ${dep} then modCandidates.${dep} else externalModMap.${dep}) deps)) modDepsMap;
+  makeEmacsWrapper = name: emacs: lean: writeShellScriptBin name ''
+    ${emacs} --eval "(progn (setq lean4-rootdir \"${lean}\"))" "$@"
+  '';
+  makeVSCodeWrapper = name: lean: writeShellScriptBin name ''
+    PATH=${lean}/bin:$PATH ${lean-vscode}/bin/code "$@"
+  '';
+  printPaths = deps: writeShellScriptBin "print-paths" ''
+    echo '${toJSON {
+      oleanPath = [(depRoot "print-paths" deps)];
+      srcPath = ["."] ++ map (dep: dep.src) allExternalDeps;
+      loadDynlibPaths = map pathOfSharedLib (loadDynlibsOfDeps deps);
+    }}'
+  '';
   expandGlob = g:
     if typeOf g == "string" then [g]
     else if g.glob == "one" then [g.mod]
@@ -211,8 +224,7 @@ with builtins; let
   allLinkFlags = lib.foldr (shared: acc: acc ++ [ "-L${shared}" "-l${shared.linkName or shared.name}" ]) linkFlags allNativeSharedLibs;
 
   objects   = mapAttrs (_: m: m.obj) mods';
-  bintools = if stdenv.isDarwin then darwin.cctools else stdenv.cc.bintools.bintools;
-  staticLib = runCommand "${name}-lib" { buildInputs = [ bintools ]; } ''
+  staticLib = runCommand "${name}-lib" { buildInputs = [ stdenv.cc.bintools.bintools ]; } ''
     mkdir -p $out
     ar Trcs $out/lib${libName}.a ${lib.concatStringsSep " " (map (drv: "${drv}/${drv.oPath}") (attrValues objects))};
   '';
@@ -233,15 +245,59 @@ in rec {
   cTree     = symlinkJoin { name = "${name}-cTree"; paths = map (mod: mod.c) (attrValues mods); };
   oTree     = symlinkJoin { name = "${name}-oTree"; paths = (attrValues objects); };
   iTree     = symlinkJoin { name = "${name}-iTree"; paths = map (mod: mod.ilean) (attrValues mods); };
-  sharedLib = mkSharedLib "lib${sharedLibName}" ''
+  sharedLib = mkSharedLib "lib${libName}" ''
     ${if stdenv.isDarwin then "-Wl,-force_load,${staticLib}/lib${libName}.a" else "-Wl,--whole-archive ${staticLib}/lib${libName}.a -Wl,--no-whole-archive"} \
     ${lib.concatStringsSep " " (map (d: "${d.sharedLib}/*") deps)}'';
   executable = lib.makeOverridable ({ withSharedStdlib ? true }: let
-      objPaths = map (drv: "${drv}/${drv.oPath}") (attrValues objects) ++ lib.optional withSharedStdlib "${lean-final.leanshared}/*";
+      objPaths = map (drv: "${drv}/${drv.oPath}") (attrValues objects) ++ lib.optional withSharedStdlib "${lean-final.libInit_shared}/* ${lean-final.leanshared}/*";
     in runCommand executableName { buildInputs = [ stdenv.cc leanc ]; } ''
       mkdir -p $out/bin
       leanc ${staticLibLinkWrapper (lib.concatStringsSep " " (objPaths ++ map (d: "${d}/*.a") allStaticLibDeps))} \
         -o $out/bin/${executableName} \
         ${lib.concatStringsSep " " allLinkFlags}
     '') {};
+
+  lean-package = writeShellScriptBin "lean" ''
+    LEAN_PATH=${modRoot}:$LEAN_PATH LEAN_SRC_PATH=$LEAN_SRC_PATH:${src} exec ${lean-final}/bin/lean "$@"
+  '';
+  emacs-package = makeEmacsWrapper "emacs-package" lean-package;
+  vscode-package = makeVSCodeWrapper "vscode-package" lean-package;
+
+  link-ilean = writeShellScriptBin "link-ilean" ''
+    dest=''${1:-.}
+    mkdir -p $dest/build/lib
+    ln -sf ${iTree}/* $dest/build/lib
+  '';
+
+  makePrintPathsFor = deps: mods: printPaths deps // mapAttrs (_: mod: makePrintPathsFor (deps ++ [mod]) mods) mods;
+  print-paths = makePrintPathsFor [] (mods' // externalModMap);
+  # `lean` wrapper that dynamically runs Nix for the actual `lean` executable so the same editor can be
+  # used for multiple projects/after upgrading the `lean` input/for editing both stage 1 and the tests
+  lean-bin-dev = substituteAll {
+    name = "lean";
+    dir = "bin";
+    src = ./lean-dev.in;
+    isExecutable = true;
+    srcRoot = fullSrc;  # use root flake.nix in case of Lean repo
+    inherit bash nix srcTarget srcArgs;
+  };
+  lake-dev = substituteAll {
+    name = "lake";
+    dir = "bin";
+    src = ./lake-dev.in;
+    isExecutable = true;
+    srcRoot = fullSrc;  # use root flake.nix in case of Lean repo
+    inherit bash nix srcTarget srcArgs;
+  };
+  lean-dev = symlinkJoin { name = "lean-dev"; paths = [ lean-bin-dev lake-dev ]; };
+  emacs-dev = makeEmacsWrapper "emacs-dev" "${lean-emacs}/bin/emacs" lean-dev;
+  emacs-path-dev = makeEmacsWrapper "emacs-path-dev" "emacs" lean-dev;
+  vscode-dev = makeVSCodeWrapper "vscode-dev" lean-dev;
+
+  devShell = mkShell {
+    buildInputs = [ nix ];
+    shellHook = ''
+      export LEAN_SRC_PATH="${srcPath}"
+    '';
+  };
 })

nix/packages.nix

@@ -1,6 +1,9 @@
-{ src, pkgs, ... } @ args:
+{ src, pkgs, nix, ... } @ args:
 with pkgs;
 let
+  nix-pinned = writeShellScriptBin "nix" ''
+    ${nix.packages.${system}.default}/bin/nix --experimental-features 'nix-command flakes' --extra-substituters https://lean4.cachix.org/ --option warn-dirty false "$@"
+  '';
   # https://github.com/NixOS/nixpkgs/issues/130963
   llvmPackages = if stdenv.isDarwin then llvmPackages_11 else llvmPackages_15;
   cc = (ccacheWrapper.override rec {
@@ -39,9 +42,40 @@ let
     inherit (lean) stdenv;
     lean = lean.stage1;
     inherit (lean.stage1) leanc;
+    inherit lean-emacs lean-vscode;
+    nix = nix-pinned;
   }));
+  lean4-mode = emacsPackages.melpaBuild {
+    pname = "lean4-mode";
+    version = "1";
+    commit = "1";
+    src = args.lean4-mode;
+    packageRequires = with pkgs.emacsPackages.melpaPackages; [ dash f flycheck magit-section lsp-mode s ];
+    recipe = pkgs.writeText "recipe" ''
+      (lean4-mode
+       :repo "leanprover/lean4-mode"
+       :fetcher github
+       :files ("*.el" "data"))
+    '';
+  };
+  lean-emacs = emacsWithPackages [ lean4-mode ];
+  # updating might be nicer by building from source from a flake input, but this is good enough for now
+  vscode-lean4 = vscode-utils.extensionFromVscodeMarketplace {
+      name = "lean4";
+      publisher = "leanprover";
+      version = "0.0.63";
+      sha256 = "sha256-kjEex7L0F2P4pMdXi4NIZ1y59ywJVubqDqsoYagZNkI=";
+  };
+  lean-vscode = vscode-with-extensions.override {
+    vscodeExtensions = [ vscode-lean4 ];
+  };
 in {
-  inherit cc buildLeanPackage llvmPackages;
+  inherit cc lean4-mode buildLeanPackage llvmPackages vscode-lean4;
+  lean = lean.stage1;
+  stage0print-paths = lean.stage1.Lean.print-paths;
+  HEAD-as-stage0 = (lean.stage1.Lean.overrideArgs { srcTarget = "..#stage0-from-input.stage0"; srcArgs = "(--override-input lean-stage0 ..\?rev=$(git rev-parse HEAD) -- -Dinterpreter.prefer_native=false \"$@\")"; });
+  HEAD-as-stage1 = (lean.stage1.Lean.overrideArgs { srcTarget = "..\?rev=$(git rev-parse HEAD)#stage0"; });
+  nix = nix-pinned;
   nixpkgs = pkgs;
   ciShell = writeShellScriptBin "ciShell" ''
     set -o pipefail
@@ -49,4 +83,5 @@ in {
     # prefix lines with cumulative and individual execution time
     "$@" |& ts -i "(%.S)]" | ts -s "[%M:%S"
   '';
-} // lean.stage1
+  vscode = lean-vscode;
+} // lean.stage1.Lean // lean.stage1 // lean

releases_drafts/README.md

@@ -1,22 +0,0 @@
-Draft release notes
--------------------
-
-This folder contains drafts of release notes for inclusion in `RELEASES.md`.
-During the process to create a release candidate, we look through all the commits that make up the release
-to prepare the release notes, and in that process we take these drafts into account.
-
-Guidelines:
-- You should prefer adding release notes to commit messages over adding anything to this folder.
-  A release note should briefly explain the impact of a change from a user's point of view.
-  Please mark these parts out with words such as **release notes** and/or **breaking changes**.
-- It is not necessary to add anything to this folder. It is meant for larger features that span multiple PRs,
-  or for anything that would be helpful when preparing the release notes that might be missed
-  by someone reading through the change log.
-- If the PR that adds a feature simultaneously adds a draft release note, including the PR number is not required
-  since it can be obtained from the git history for the file.
-
-When release notes are prepared, all the draft release notes are deleted from this folder.
-For release candidates beyond the first one, you can either update `RELEASE.md` directly
-or continue to add drafts.
-
-When a release is finalized, we will copy the completed release notes from `RELEASE.md` to the `master` branch.

releases_drafts/hashmap.md

@@ -1,3 +0,0 @@
-* 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

@@ -1 +0,0 @@
-* #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/lib/README.md

@@ -1,2 +0,0 @@
-This directory contains various scripts that are *not* meant to be called
-directly, but through other scripts or makefiles.

script/lib/rebase-editor.sh

@@ -1,19 +0,0 @@
-#!/usr/bin/env bash
-
-
-# Script internal to `./script/rebase-stage0.sh`
-
-# Determine OS type for sed in-place editing
-SED_CMD=("sed" "-i")
-if [[ "$OSTYPE" == "darwin"* ]]
-then
-    # macOS requires an empty string argument with -i for in-place editing
-    SED_CMD=("sed" "-i" "")
-fi
-
-if [ "$STAGE0_WITH_NIX" = true ]
-then
-  "${SED_CMD[@]}" '/chore: update stage0/ s,.*,x nix run .#update-stage0-commit,' "$1"
-else
-  "${SED_CMD[@]}" '/chore: update stage0/ s,.*,x make -j32 -C build/release update-stage0 \&\& git commit -m "chore: update stage0",' "$1"
-fi

script/lib/update-stage0

@@ -1,33 +0,0 @@
-#!/usr/bin/env bash
-set -euo pipefail
-
-rm -r stage0 || true
-# don't copy untracked files
-# `:!` is git glob flavor for exclude patterns
-for f in $(git ls-files src ':!:src/lake/*' ':!:src/Leanc.lean'); do
-    if [[ $f == *.lean ]]; then
-        f=${f#src/}
-        f=${f%.lean}.c
-        mkdir -p $(dirname stage0/stdlib/$f)
-        cp ${CP_C_PARAMS:-} $CSRCS/$f stage0/stdlib/$f
-    else
-        mkdir -p $(dirname stage0/$f)
-        cp $f stage0/$f
-    fi
-done
-
-# special handling for Lake files due to its nested directory
-# copy the README to ensure the `stage0/src/lake` directory is committed
-for f in $(git ls-files 'src/lake/Lake/*' src/lake/Lake.lean src/lake/LakeMain.lean src/lake/README.md ':!:src/lakefile.toml'); do
-    if [[ $f == *.lean ]]; then
-        f=${f#src/lake}
-        f=${f%.lean}.c
-        mkdir -p $(dirname stage0/stdlib/$f)
-        cp ${CP_C_PARAMS:-} $CSRCS/$f stage0/stdlib/$f
-    else
-        mkdir -p $(dirname stage0/$f)
-        cp $f stage0/$f
-    fi
-done
-
-git add stage0

script/prepare-llvm-linux.sh

@@ -38,7 +38,7 @@ $CP $GLIBC/lib/*crt* llvm/lib/
 $CP $GLIBC/lib/*crt* stage1/lib/
 # runtime
 (cd llvm; $CP --parents lib/clang/*/lib/*/{clang_rt.*.o,libclang_rt.builtins*} ../stage1)
-$CP llvm/lib/*/lib{c++,c++abi,unwind}.* $GMP/lib/libgmp.a $LIBUV/lib/libuv.a stage1/lib/
+$CP llvm/lib/*/lib{c++,c++abi,unwind}.* $GMP/lib/libgmp.a stage1/lib/
 # LLVM 15 appears to ship the dependencies in 'llvm/lib/<target-triple>/' and 'llvm/include/<target-triple>/'
 # but clang-15 that we use to compile is linked against 'llvm/lib/' and 'llvm/include'
 # https://github.com/llvm/llvm-project/issues/54955
@@ -62,8 +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 -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 -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 -Wl,--no-as-needed'"
+echo -n " -DLEAN_EXTRA_LINKER_FLAGS='-Wl,--as-needed -lgmp -Wl,--no-as-needed'"
 # do not set `LEAN_CC` for tests
 echo -n " -DLEAN_TEST_VARS=''"

script/prepare-llvm-macos.sh

@@ -9,7 +9,6 @@ set -uxo pipefail
 # use full LLVM release for compiling C++ code, but subset for compiling C code and distribution
 
 GMP=${GMP:-$(brew --prefix)}
-LIBUV=${LIBUV:-$(brew --prefix)}
 
 [[ -d llvm ]] || (mkdir llvm; gtar xf $1 --strip-components 1 --directory llvm)
 [[ -d llvm-host ]] || if [[ "$#" -gt 1 ]]; then
@@ -47,9 +46,8 @@ echo -n " -DLEAN_EXTRA_CXX_FLAGS='${EXTRA_FLAGS:-}'"
 if [[ -L llvm-host ]]; then
   echo -n " -DCMAKE_C_COMPILER=$PWD/stage1/bin/clang"
   gcp $GMP/lib/libgmp.a stage1/lib/
-  gcp $LIBUV/lib/libuv.a stage1/lib/
   echo -n " -DLEANC_INTERNAL_LINKER_FLAGS='-L ROOT/lib -L ROOT/lib/libc -fuse-ld=lld'"
-  echo -n " -DLEAN_EXTRA_LINKER_FLAGS='-lgmp -luv'"
+  echo -n " -DLEAN_EXTRA_LINKER_FLAGS='-lgmp'"
 else
   echo -n " -DCMAKE_C_COMPILER=$PWD/llvm-host/bin/clang -DLEANC_OPTS='--sysroot $PWD/stage1 -resource-dir $PWD/stage1/lib/clang/15.0.1 ${EXTRA_FLAGS:-}'"
   echo -n " -DLEANC_INTERNAL_LINKER_FLAGS='-L ROOT/lib -L ROOT/lib/libc -fuse-ld=lld'"

script/prepare-llvm-mingw.sh

@@ -31,15 +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
-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/
+cp /clang64/lib/lib{m,bcrypt,mingw32,moldname,mingwex,msvcrt,pthread,advapi32,shell32,user32,kernel32,ucrtbase}.* /clang64/lib/libgmp.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 -luv -lunwind -Wl,-Bdynamic -fuse-ld=lld'"
+echo -n " -DLEANC_INTERNAL_LINKER_FLAGS='-L ROOT/lib -static-libgcc -Wl,-Bstatic -lgmp -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'"
+echo -n " -DLEAN_EXTRA_LINKER_FLAGS='-lgmp -lucrtbase'"
 # do not set `LEAN_CC` for tests
 echo -n " -DAUTO_THREAD_FINALIZATION=OFF -DSTAGE0_AUTO_THREAD_FINALIZATION=OFF"
 echo -n " -DLEAN_TEST_VARS=''"

script/rebase-stage0.sh

@@ -1,24 +0,0 @@
-#!/usr/bin/env bash
-
-# This script rebases onto the given branch/commit, and updates
-# all `chore: update stage0` commits along the way.
-
-# Whether to use nix or make to update stage0
-if [ "$1" = "-nix" ]
-then
-   export STAGE0_WITH_NIX=true
-   shift
-fi
-
-# Check if an argument is provided
-if [ "$#" -eq 0 ]; then
-    echo "Usage: $0 [-nix] <options to git rebase -i>"
-    exit 1
-fi
-
-REPO_ROOT=$(git rev-parse --show-toplevel)
-
-# Run git rebase in interactive mode, but automatically edit the todo list
-# using the defined GIT_SEQUENCE_EDITOR command
-GIT_SEQUENCE_EDITOR="$REPO_ROOT/script/lib/rebase-editor.sh" git rebase -i "$@"
-

script/update-stage0

@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+rm -r stage0 || true
+# don't copy untracked files
+# `:!` is git glob flavor for exclude patterns
+for f in $(git ls-files src ':!:src/lake/*' ':!:src/Leanc.lean'); do
+    if [[ $f == *.lean ]]; then
+        f=${f#src/}
+        f=${f%.lean}.c
+        mkdir -p $(dirname stage0/stdlib/$f)
+        cp ${CP_C_PARAMS:-} $CSRCS/$f stage0/stdlib/$f
+    else
+        mkdir -p $(dirname stage0/$f)
+        cp $f stage0/$f
+    fi
+done
+git add stage0

src/CMakeLists.txt

@@ -1,6 +1,5 @@
 cmake_minimum_required(VERSION 3.10)
 cmake_policy(SET CMP0054 NEW)
-cmake_policy(SET CMP0110 NEW)
 if(NOT (${CMAKE_GENERATOR} MATCHES "Unix Makefiles"))
   message(FATAL_ERROR "The only supported CMake generator at the moment is 'Unix Makefiles'")
 endif()
@@ -10,7 +9,7 @@ endif()
 include(ExternalProject)
 project(LEAN CXX C)
 set(LEAN_VERSION_MAJOR 4)
-set(LEAN_VERSION_MINOR 12)
+set(LEAN_VERSION_MINOR 8)
 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'")
@@ -74,7 +73,6 @@ option(USE_GMP "USE_GMP" ON)
 
 # development-specific options
 option(CHECK_OLEAN_VERSION "Only load .olean files compiled with the current version of Lean" OFF)
-option(USE_LAKE "Use Lake instead of lean.mk for building core libs from language server" OFF)
 
 set(LEAN_EXTRA_MAKE_OPTS  ""                           CACHE STRING "extra options to lean --make")
 set(LEANC_CC              ${CMAKE_C_COMPILER}          CACHE STRING "C compiler to use in `leanc`")
@@ -243,15 +241,6 @@ if("${USE_GMP}" MATCHES "ON")
   endif()
 endif()
 
-if(NOT "${CMAKE_SYSTEM_NAME}" MATCHES "Emscripten")
-  # LibUV
-  find_package(LibUV 1.0.0 REQUIRED)
-  include_directories(${LIBUV_INCLUDE_DIR})
-endif()
-if(NOT LEAN_STANDALONE)
-  string(APPEND LEAN_EXTRA_LINKER_FLAGS " ${LIBUV_LIBRARIES}")
-endif()
-
 # ccache
 if(CCACHE AND NOT CMAKE_CXX_COMPILER_LAUNCHER AND NOT CMAKE_C_COMPILER_LAUNCHER)
   find_program(CCACHE_PATH ccache)
@@ -310,11 +299,11 @@ if(${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
     cmake_path(GET ZLIB_LIBRARY PARENT_PATH ZLIB_LIBRARY_PARENT_PATH)
     string(APPEND LEANSHARED_LINKER_FLAGS " -L ${ZLIB_LIBRARY_PARENT_PATH}")
   endif()
-  string(APPEND TOOLCHAIN_STATIC_LINKER_FLAGS " -lleancpp -lInit -lStd -lLean -lleanrt")
+  string(APPEND TOOLCHAIN_STATIC_LINKER_FLAGS " -lleancpp -lInit -lLean -lleanrt")
 elseif(${CMAKE_SYSTEM_NAME} MATCHES "Emscripten")
-  string(APPEND TOOLCHAIN_STATIC_LINKER_FLAGS " -lleancpp -lInit -lStd -lLean -lnodefs.js -lleanrt")
+  string(APPEND TOOLCHAIN_STATIC_LINKER_FLAGS " -lleancpp -lInit -lLean -lnodefs.js -lleanrt")
 else()
-  string(APPEND TOOLCHAIN_STATIC_LINKER_FLAGS " -Wl,--start-group -lleancpp -lLean -Wl,--end-group -lStd -Wl,--start-group -lInit -lleanrt -Wl,--end-group")
+  string(APPEND TOOLCHAIN_STATIC_LINKER_FLAGS " -Wl,--start-group -lleancpp -lLean -Wl,--end-group -Wl,--start-group -lInit -lleanrt -Wl,--end-group")
 endif()
 
 set(LEAN_CXX_STDLIB "-lstdc++" CACHE STRING "C++ stdlib linker flags")
@@ -326,19 +315,8 @@ endif()
 string(APPEND TOOLCHAIN_STATIC_LINKER_FLAGS " ${LEAN_CXX_STDLIB}")
 string(APPEND TOOLCHAIN_SHARED_LINKER_FLAGS " ${LEAN_CXX_STDLIB}")
 
-# in local builds, link executables and not just dynlibs against C++ stdlib as well,
-# which is required for e.g. asan
-if(NOT LEAN_STANDALONE)
-  string(APPEND CMAKE_EXE_LINKER_FLAGS " ${LEAN_CXX_STDLIB}")
-endif()
-
 # flags for user binaries = flags for toolchain binaries + Lake
-set(LEANC_STATIC_LINKER_FLAGS " ${TOOLCHAIN_STATIC_LINKER_FLAGS} -lLake")
-if(${CMAKE_SYSTEM_NAME} MATCHES "Linux")
-  set(LEANC_SHARED_LINKER_FLAGS " ${TOOLCHAIN_SHARED_LINKER_FLAGS} -Wl,--as-needed -lLake_shared -Wl,--no-as-needed")
-else()
-  set(LEANC_SHARED_LINKER_FLAGS " ${TOOLCHAIN_SHARED_LINKER_FLAGS} -lLake_shared")
-endif()
+string(APPEND LEANC_STATIC_LINKER_FLAGS " ${TOOLCHAIN_STATIC_LINKER_FLAGS} -lLake")
 
 if (LLVM)
   string(APPEND LEANSHARED_LINKER_FLAGS " -L${LLVM_CONFIG_LIBDIR} ${LLVM_CONFIG_LDFLAGS} ${LLVM_CONFIG_LIBS} ${LLVM_CONFIG_SYSTEM_LIBS}")
@@ -383,20 +361,15 @@ if(${CMAKE_SYSTEM_NAME} MATCHES "Linux")
   string(APPEND CMAKE_CXX_FLAGS " -fPIC -ftls-model=initial-exec")
   string(APPEND LEANC_EXTRA_FLAGS " -fPIC")
   string(APPEND TOOLCHAIN_SHARED_LINKER_FLAGS " -Wl,-rpath=\\$$ORIGIN/..:\\$$ORIGIN")
-  string(APPEND LAKESHARED_LINKER_FLAGS " -Wl,--whole-archive ${CMAKE_BINARY_DIR}/lib/temp/libLake.a.export -Wl,--no-whole-archive")
   string(APPEND CMAKE_EXE_LINKER_FLAGS " -Wl,-rpath=\\\$ORIGIN/../lib:\\\$ORIGIN/../lib/lean")
 elseif(${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
   string(APPEND CMAKE_CXX_FLAGS " -ftls-model=initial-exec")
   string(APPEND INIT_SHARED_LINKER_FLAGS " -install_name @rpath/libInit_shared.dylib")
-  string(APPEND LEANSHARED_1_LINKER_FLAGS " -install_name @rpath/libleanshared_1.dylib")
   string(APPEND LEANSHARED_LINKER_FLAGS " -install_name @rpath/libleanshared.dylib")
-  string(APPEND LAKESHARED_LINKER_FLAGS " -Wl,-force_load,${CMAKE_BINARY_DIR}/lib/temp/libLake.a.export -install_name @rpath/libLake_shared.dylib")
   string(APPEND CMAKE_EXE_LINKER_FLAGS " -Wl,-rpath,@executable_path/../lib -Wl,-rpath,@executable_path/../lib/lean")
 elseif(${CMAKE_SYSTEM_NAME} MATCHES "Emscripten")
   string(APPEND CMAKE_CXX_FLAGS " -fPIC")
   string(APPEND LEANC_EXTRA_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()
 
 if(${CMAKE_SYSTEM_NAME} MATCHES "Linux")
@@ -421,8 +394,8 @@ endif()
 # executable or `leanshared`, plugins would try to look them up at load time (even though they
 # are already loaded) and probably fail unless we set up LD_LIBRARY_PATH.
 if(${CMAKE_SYSTEM_NAME} MATCHES "Windows")
-  # import libraries created by the stdlib.make targets
-  string(APPEND LEANC_SHARED_LINKER_FLAGS " -lInit_shared -lleanshared_1 -lleanshared")
+  # import library created by the `leanshared` target
+  string(APPEND LEANC_SHARED_LINKER_FLAGS " -lInit_shared -lleanshared")
 elseif("${CMAKE_SYSTEM_NAME}" MATCHES "Darwin")
   string(APPEND LEANC_SHARED_LINKER_FLAGS " -Wl,-undefined,dynamic_lookup")
 endif()
@@ -479,22 +452,6 @@ if(CMAKE_OSX_SYSROOT AND NOT LEAN_STANDALONE)
   string(APPEND LEANC_EXTRA_FLAGS " ${CMAKE_CXX_SYSROOT_FLAG}${CMAKE_OSX_SYSROOT}")
 endif()
 
-add_subdirectory(initialize)
-add_subdirectory(shell)
-# to be included in `leanshared` but not the smaller `leanshared_1` (as it would pull
-# in the world)
-add_library(leaninitialize STATIC $<TARGET_OBJECTS:initialize>)
-set_target_properties(leaninitialize PROPERTIES
-  ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib/temp
-  OUTPUT_NAME leaninitialize)
-add_library(leanshell STATIC util/shell.cpp)
-set_target_properties(leanshell PROPERTIES
-  ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib/temp
-  OUTPUT_NAME leanshell)
-if (${CMAKE_SYSTEM_NAME} MATCHES "Windows")
-  string(APPEND CMAKE_EXE_LINKER_FLAGS " -Wl,--whole-archive -lleanmanifest -Wl,--no-whole-archive")
-endif()
-
 if(${STAGE} GREATER 1)
   # reuse C++ parts, which don't change
   add_library(leanrt_initial-exec STATIC IMPORTED)
@@ -503,17 +460,13 @@ if(${STAGE} GREATER 1)
   add_library(leanrt STATIC IMPORTED)
   set_target_properties(leanrt PROPERTIES
     IMPORTED_LOCATION "${CMAKE_BINARY_DIR}/lib/lean/libleanrt.a")
-  add_library(leancpp_1 STATIC IMPORTED)
-  set_target_properties(leancpp_1 PROPERTIES
-    IMPORTED_LOCATION "${CMAKE_BINARY_DIR}/lib/temp/libleancpp_1.a")
   add_library(leancpp STATIC IMPORTED)
   set_target_properties(leancpp PROPERTIES
     IMPORTED_LOCATION "${CMAKE_BINARY_DIR}/lib/lean/libleancpp.a")
   add_custom_target(copy-leancpp
     COMMAND cmake -E copy_if_different "${PREV_STAGE}/runtime/libleanrt_initial-exec.a" "${CMAKE_BINARY_DIR}/runtime/libleanrt_initial-exec.a"
     COMMAND cmake -E copy_if_different "${PREV_STAGE}/lib/lean/libleanrt.a" "${CMAKE_BINARY_DIR}/lib/lean/libleanrt.a"
-    COMMAND cmake -E copy_if_different "${PREV_STAGE}/lib/lean/libleancpp.a" "${CMAKE_BINARY_DIR}/lib/lean/libleancpp.a"
-    COMMAND cmake -E copy_if_different "${PREV_STAGE}/lib/temp/libleancpp_1.a" "${CMAKE_BINARY_DIR}/lib/temp/libleancpp_1.a")
+    COMMAND cmake -E copy_if_different "${PREV_STAGE}/lib/lean/libleancpp.a" "${CMAKE_BINARY_DIR}/lib/lean/libleancpp.a")
   add_dependencies(leancpp copy-leancpp)
   if(LLVM)
       add_custom_target(copy-lean-h-bc
@@ -533,23 +486,14 @@ else()
   set(LEAN_OBJS ${LEAN_OBJS} $<TARGET_OBJECTS:constructions>)
   add_subdirectory(library/compiler)
   set(LEAN_OBJS ${LEAN_OBJS} $<TARGET_OBJECTS:compiler>)
+  add_subdirectory(initialize)
+  set(LEAN_OBJS ${LEAN_OBJS} $<TARGET_OBJECTS:initialize>)
 
-  # leancpp without `initialize` (see `leaninitialize` above)
-  add_library(leancpp_1 STATIC ${LEAN_OBJS})
-  set_target_properties(leancpp_1 PROPERTIES
-    ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib/temp
-    OUTPUT_NAME leancpp_1)
-  add_library(leancpp STATIC ${LEAN_OBJS} $<TARGET_OBJECTS:initialize>)
+  add_library(leancpp STATIC ${LEAN_OBJS})
   set_target_properties(leancpp PROPERTIES
     OUTPUT_NAME leancpp)
 endif()
 
-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)
-endif()
-
 # MSYS2 bash usually handles Windows paths relatively well, but not when putting them in the PATH
 string(REGEX REPLACE "^([a-zA-Z]):" "/\\1" LEAN_BIN "${CMAKE_BINARY_DIR}/bin")
 
@@ -557,12 +501,25 @@ string(REGEX REPLACE "^([a-zA-Z]):" "/\\1" LEAN_BIN "${CMAKE_BINARY_DIR}/bin")
 # (also looks nicer in the build log)
 file(RELATIVE_PATH LIB ${LEAN_SOURCE_DIR} ${CMAKE_BINARY_DIR}/lib)
 
+# set up libInit_shared only on Windows; see also stdlib.make.in
+if(${CMAKE_SYSTEM_NAME} MATCHES "Windows")
+  set(INIT_SHARED_LINKER_FLAGS "-Wl,--whole-archive ${CMAKE_BINARY_DIR}/lib/temp/libInit.a.export ${CMAKE_BINARY_DIR}/runtime/libleanrt_initial-exec.a -Wl,--no-whole-archive -Wl,--out-implib,${CMAKE_BINARY_DIR}/lib/lean/libInit_shared.dll.a")
+endif()
+
+if(${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
+  set(LEANSHARED_LINKER_FLAGS "-Wl,-force_load,${CMAKE_BINARY_DIR}/lib/lean/libInit.a -Wl,-force_load,${CMAKE_BINARY_DIR}/lib/lean/libLean.a -Wl,-force_load,${CMAKE_BINARY_DIR}/lib/lean/libleancpp.a ${CMAKE_BINARY_DIR}/runtime/libleanrt_initial-exec.a ${LEANSHARED_LINKER_FLAGS}")
+elseif(${CMAKE_SYSTEM_NAME} MATCHES "Windows")
+  set(LEANSHARED_LINKER_FLAGS "-Wl,--whole-archive ${CMAKE_BINARY_DIR}/lib/temp/libLean.a.export -lleancpp -Wl,--no-whole-archive -lInit_shared -Wl,--out-implib,${CMAKE_BINARY_DIR}/lib/lean/libleanshared.dll.a")
+else()
+  set(LEANSHARED_LINKER_FLAGS "-Wl,--whole-archive -lInit -lLean -lleancpp -Wl,--no-whole-archive ${CMAKE_BINARY_DIR}/runtime/libleanrt_initial-exec.a ${LEANSHARED_LINKER_FLAGS}")
+endif()
+
 if (${CMAKE_SYSTEM_NAME} MATCHES "Emscripten")
   # We do not use dynamic linking via leanshared for Emscripten to keep things
   # 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".
-  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")
+  string(APPEND LEAN_EXE_LINKER_FLAGS " ${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
@@ -576,7 +533,7 @@ add_custom_target(make_stdlib ALL
   # The actual rule is in a separate makefile because we want to prefix it with '+' to use the Make job server
   # for a parallelized nested build, but CMake doesn't let us do that.
   # We use `lean` from the previous stage, but `leanc`, headers, etc. from the current stage
-  COMMAND $(MAKE) -f ${CMAKE_BINARY_DIR}/stdlib.make Init Std Lean
+  COMMAND $(MAKE) -f ${CMAKE_BINARY_DIR}/stdlib.make Init Lean
   VERBATIM)
 
 # if we have LLVM enabled, then build `lean.h.bc` which has the LLVM bitcode
@@ -596,13 +553,8 @@ if(${CMAKE_SYSTEM_NAME} MATCHES "Emscripten")
   )
   add_custom_target(leanshared ALL
     DEPENDS Init_shared leancpp
-    COMMAND touch ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/libleanshared_1${CMAKE_SHARED_LIBRARY_SUFFIX}
     COMMAND touch ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/libleanshared${CMAKE_SHARED_LIBRARY_SUFFIX}
   )
-  add_custom_target(lake_shared ALL
-    DEPENDS leanshared
-    COMMAND touch ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/libLake_shared${CMAKE_SHARED_LIBRARY_SUFFIX}
-  )
 else()
   add_custom_target(Init_shared ALL
     WORKING_DIRECTORY ${LEAN_SOURCE_DIR}
@@ -612,34 +564,28 @@ else()
 
   add_custom_target(leanshared ALL
     WORKING_DIRECTORY ${LEAN_SOURCE_DIR}
-    DEPENDS Init_shared leancpp_1 leancpp leanshell leaninitialize
+    DEPENDS Init_shared leancpp
     COMMAND $(MAKE) -f ${CMAKE_BINARY_DIR}/stdlib.make leanshared
     VERBATIM)
 
-  string(APPEND CMAKE_EXE_LINKER_FLAGS " -lInit_shared -lleanshared_1 -lleanshared")
+  string(APPEND CMAKE_EXE_LINKER_FLAGS " -lInit_shared -lleanshared")
 endif()
 
-if(NOT ${CMAKE_SYSTEM_NAME} MATCHES "Emscripten")
-  add_custom_target(lake_lib ALL
+if(${STAGE} GREATER 0 AND NOT ${CMAKE_SYSTEM_NAME} MATCHES "Emscripten")
+  if(NOT EXISTS ${LEAN_SOURCE_DIR}/lake/Lake.lean)
+    message(FATAL_ERROR "src/lake does not exist. Please check out the Lake submodule using `git submodule update --init src/lake`.")
+  endif()
+
+  add_custom_target(lake ALL
     WORKING_DIRECTORY ${LEAN_SOURCE_DIR}
     DEPENDS leanshared
     COMMAND $(MAKE) -f ${CMAKE_BINARY_DIR}/stdlib.make Lake
     VERBATIM)
-  add_custom_target(lake_shared ALL
-    WORKING_DIRECTORY ${LEAN_SOURCE_DIR}
-    DEPENDS lake_lib
-    COMMAND $(MAKE) -f ${CMAKE_BINARY_DIR}/stdlib.make libLake_shared
-    VERBATIM)
-  add_custom_target(lake ALL
-    WORKING_DIRECTORY ${LEAN_SOURCE_DIR}
-    DEPENDS lake_shared
-    COMMAND $(MAKE) -f ${CMAKE_BINARY_DIR}/stdlib.make lake
-    VERBATIM)
 endif()
 
 if(PREV_STAGE)
   add_custom_target(update-stage0
-    COMMAND bash -c 'CSRCS=${CMAKE_BINARY_DIR}/lib/temp script/lib/update-stage0'
+    COMMAND bash -c 'CSRCS=${CMAKE_BINARY_DIR}/lib/temp script/update-stage0'
     DEPENDS make_stdlib
     WORKING_DIRECTORY "${LEAN_SOURCE_DIR}/..")
 
@@ -663,9 +609,7 @@ file(COPY ${LEAN_SOURCE_DIR}/bin/leanmake DESTINATION ${CMAKE_BINARY_DIR}/bin)
 
 install(DIRECTORY "${CMAKE_BINARY_DIR}/bin/" USE_SOURCE_PERMISSIONS DESTINATION bin)
 
-if (${STAGE} GREATER 0 AND CADICAL)
-  install(PROGRAMS "${CADICAL}" DESTINATION bin)
-endif()
+add_subdirectory(shell)
 
 add_custom_target(clean-stdlib
   COMMAND rm -rf "${CMAKE_BINARY_DIR}/lib" || true)
@@ -708,9 +652,3 @@ endif()
 string(REPLACE "$" "$$" CMAKE_EXE_LINKER_FLAGS_MAKE "${CMAKE_EXE_LINKER_FLAGS}")
 string(REPLACE "$" "$$" CMAKE_EXE_LINKER_FLAGS_MAKE_MAKE "${CMAKE_EXE_LINKER_FLAGS_MAKE}")
 configure_file(${LEAN_SOURCE_DIR}/stdlib.make.in ${CMAKE_BINARY_DIR}/stdlib.make)
-
-if(USE_LAKE AND STAGE EQUAL 1)
-  configure_file(${LEAN_SOURCE_DIR}/lakefile.toml.in ${LEAN_SOURCE_DIR}/lakefile.toml)
-  configure_file(${LEAN_SOURCE_DIR}/lakefile.toml.in ${LEAN_SOURCE_DIR}/../tests/lakefile.toml)
-  configure_file(${LEAN_SOURCE_DIR}/lakefile.toml.in ${LEAN_SOURCE_DIR}/../lakefile.toml)
-endif()

src/Init.lean

@@ -34,4 +34,3 @@ import Init.BinderPredicates
 import Init.Ext
 import Init.Omega
 import Init.MacroTrace
-import Init.Grind

src/Init/ByCases.lean

@@ -37,26 +37,29 @@ theorem apply_ite (f : α → β) (P : Prop) [Decidable P] (x y : α) :
     f (ite P x y) = ite P (f x) (f y) :=
   apply_dite f P (fun _ => x) (fun _ => y)
 
+@[simp] theorem dite_eq_left_iff {P : Prop} [Decidable P] {B : ¬ P → α} :
+    dite P (fun _ => a) B = a ↔ ∀ h, B h = a := by
+  by_cases P <;> simp [*, forall_prop_of_true, forall_prop_of_false]
+
+@[simp] theorem dite_eq_right_iff {P : Prop} [Decidable P] {A : P → α} :
+    (dite P A fun _ => b) = b ↔ ∀ h, A h = b := by
+  by_cases P <;> simp [*, forall_prop_of_true, forall_prop_of_false]
+
+@[simp] theorem ite_eq_left_iff {P : Prop} [Decidable P] : ite P a b = a ↔ ¬P → b = a :=
+  dite_eq_left_iff
+
+@[simp] theorem ite_eq_right_iff {P : Prop} [Decidable P] : ite P a b = b ↔ P → a = b :=
+  dite_eq_right_iff
+
 /-- A `dite` whose results do not actually depend on the condition may be reduced to an `ite`. -/
 @[simp] theorem dite_eq_ite [Decidable P] : (dite P (fun _ => a) fun _ => b) = ite P a b := rfl
 
-@[deprecated "Use `ite_eq_right_iff`" (since := "2024-09-18")]
+-- We don't mark this as `simp` as it is already handled by `ite_eq_right_iff`.
 theorem ite_some_none_eq_none [Decidable P] :
     (if P then some x else none) = none ↔ ¬ P := by
-  simp only [ite_eq_right_iff, reduceCtorEq]
+  simp only [ite_eq_right_iff]
   rfl
 
-@[deprecated "Use `Option.ite_none_right_eq_some`" (since := "2024-09-18")]
-theorem ite_some_none_eq_some [Decidable P] :
+@[simp] theorem ite_some_none_eq_some [Decidable P] :
     (if P then some x else none) = some y ↔ P ∧ x = y := by
   split <;> simp_all
-
-@[deprecated "Use `dite_eq_right_iff" (since := "2024-09-18")]
-theorem dite_some_none_eq_none [Decidable P] {x : P → α} :
-    (if h : P then some (x h) else none) = none ↔ ¬P := by
-  simp
-
-@[deprecated "Use `Option.dite_none_right_eq_some`" (since := "2024-09-18")]
-theorem dite_some_none_eq_some [Decidable P] {x : P → α} {y : α} :
-    (if h : P then some (x h) else none) = some y ↔ ∃ h : P, x h = y := by
-  by_cases h : P <;> simp [h]

src/Init/Classical.lean

@@ -121,11 +121,11 @@ theorem propComplete (a : Prop) : a = True ∨ a = False :=
   | Or.inl ha => Or.inl (eq_true ha)
   | Or.inr hn => Or.inr (eq_false hn)
 
--- this supersedes byCases in Decidable
+-- this supercedes byCases in Decidable
 theorem byCases {p q : Prop} (hpq : p → q) (hnpq : ¬p → q) : q :=
   Decidable.byCases (dec := propDecidable _) hpq hnpq
 
--- this supersedes byContradiction in Decidable
+-- this supercedes byContradiction in Decidable
 theorem byContradiction {p : Prop} (h : ¬p → False) : p :=
   Decidable.byContradiction (dec := propDecidable _) h
 
@@ -134,30 +134,6 @@ The left-to-right direction, double negation elimination (DNE),
 is classically true but not constructively. -/
 @[simp] theorem not_not : ¬¬a ↔ a := Decidable.not_not
 
-/-- Transfer decidability of `¬ p` to decidability of `p`. -/
--- This can not be an instance as it would be tried everywhere.
-def decidable_of_decidable_not (p : Prop) [h : Decidable (¬ p)] : Decidable p :=
-  match h with
-  | isFalse h => isTrue (Classical.not_not.mp h)
-  | isTrue h => isFalse h
-
-attribute [local instance] decidable_of_decidable_not in
-/-- Negation of the condition `P : Prop` in a `dite` is the same as swapping the branches. -/
-@[simp low] protected theorem dite_not [hn : Decidable (¬p)] (x : ¬p → α) (y : ¬¬p → α) :
-    dite (¬p) x y = dite p (fun h => y (not_not_intro h)) x := by
-  cases hn <;> rename_i g
-  · simp [not_not.mp g]
-  · simp [g]
-
-attribute [local instance] decidable_of_decidable_not in
-/-- Negation of the condition `P : Prop` in a `ite` is the same as swapping the branches. -/
-@[simp low] protected theorem ite_not (p : Prop) [Decidable (¬ p)] (x y : α) : ite (¬p) x y = ite p y x :=
-  dite_not (fun _ => x) (fun _ => y)
-
-attribute [local instance] decidable_of_decidable_not in
-@[simp low] protected theorem decide_not (p : Prop) [Decidable (¬ p)] : decide (¬p) = !decide p :=
-  byCases (fun h : p => by simp_all) (fun h => by simp_all)
-
 @[simp low] theorem not_forall {p : α → Prop} : (¬∀ x, p x) ↔ ∃ x, ¬p x := Decidable.not_forall
 
 theorem not_forall_not {p : α → Prop} : (¬∀ x, ¬p x) ↔ ∃ x, p x := Decidable.not_forall_not
@@ -184,7 +160,7 @@ theorem not_iff : ¬(a ↔ b) ↔ (¬a ↔ b) := Decidable.not_iff
 
 @[simp] theorem not_imp : ¬(a → b) ↔ a ∧ ¬b := Decidable.not_imp_iff_and_not
 
-@[simp] theorem imp_and_neg_imp_iff (p : Prop) {q : Prop} : (p → q) ∧ (¬p → q) ↔ q :=
+@[simp] theorem imp_and_neg_imp_iff (p q : Prop) : (p → q) ∧ (¬p → q) ↔ q :=
   Iff.intro (fun (a : _ ∧ _) => (Classical.em p).rec a.left a.right)
             (fun a => And.intro (fun _ => a) (fun _ => a))
 

src/Init/Control/Basic.lean

@@ -28,7 +28,7 @@ Important instances include
 * `Option`, where `failure := none` and `<|>` returns the left-most `some`.
 * Parser combinators typically provide an `Applicative` instance for error-handling and
   backtracking.
-
+  
 Error recovery and state can interact subtly. For example, the implementation of `Alternative` for `OptionT (StateT σ Id)` keeps modifications made to the state while recovering from failure, while `StateT σ (OptionT Id)` discards them.
 -/
 -- NB: List instance is in mathlib. Once upstreamed, add

src/Init/Control/Except.lean

@@ -131,7 +131,7 @@ protected def adapt {ε' α : Type u} (f : ε → ε') : ExceptT ε m α → Exc
 end ExceptT
 
 @[always_inline]
-instance (m : Type u → Type v) (ε₁ : Type u) (ε₂ : Type u) [MonadExceptOf ε₁ m] : MonadExceptOf ε₁ (ExceptT ε₂ m) where
+instance (m : Type u → Type v) (ε₁ : Type u) (ε₂ : Type u) [Monad m] [MonadExceptOf ε₁ m] : MonadExceptOf ε₁ (ExceptT ε₂ m) where
   throw e := ExceptT.mk <| throwThe ε₁ e
   tryCatch x handle := ExceptT.mk <| tryCatchThe ε₁ x handle
 

src/Init/Control/ExceptCps.lean

@@ -34,7 +34,7 @@ instance : Monad (ExceptCpsT ε m) where
   bind x f := fun _ k₁ k₂ => x _ (fun a => f a _ k₁ k₂) k₂
 
 instance : LawfulMonad (ExceptCpsT σ m) := by
-  refine LawfulMonad.mk' _ ?_ ?_ ?_ <;> intros <;> rfl
+  refine' { .. } <;> intros <;> rfl
 
 instance : MonadExceptOf ε (ExceptCpsT ε m) where
   throw e  := fun _ _ k => k e

src/Init/Control/Lawful/Basic.lean

@@ -9,7 +9,7 @@ import Init.Meta
 
 open Function
 
-@[simp] theorem monadLift_self {m : Type u → Type v} (x : m α) : monadLift x = x :=
+@[simp] theorem monadLift_self [Monad m] (x : m α) : monadLift x = x :=
   rfl
 
 /--
@@ -153,7 +153,7 @@ namespace Id
 @[simp] theorem pure_eq (a : α) : (pure a : Id α) = a := rfl
 
 instance : LawfulMonad Id := by
-  refine LawfulMonad.mk' _ ?_ ?_ ?_ <;> intros <;> rfl
+  refine' { .. } <;> intros <;> rfl
 
 end Id
 

src/Init/Control/Lawful/Instances.lean

@@ -14,7 +14,7 @@ open Function
 
 namespace ExceptT
 
-theorem ext {x y : ExceptT ε m α} (h : x.run = y.run) : x = y := by
+theorem ext [Monad m] {x y : ExceptT ε m α} (h : x.run = y.run) : x = y := by
   simp [run] at h
   assumption
 
@@ -50,7 +50,7 @@ theorem run_bind [Monad m] (x : ExceptT ε m α)
 protected theorem seq_eq {α β ε : Type u} [Monad m] (mf : ExceptT ε m (α → β)) (x : ExceptT ε m α) : mf <*> x = mf >>= fun f => f <$> x :=
   rfl
 
-protected theorem bind_pure_comp [Monad m] (f : α → β) (x : ExceptT ε m α) : x >>= pure ∘ f = f <$> x := by
+protected theorem bind_pure_comp [Monad m] [LawfulMonad m] (f : α → β) (x : ExceptT ε m α) : x >>= pure ∘ f = f <$> x := by
   intros; rfl
 
 protected theorem seqLeft_eq {α β ε : Type u} {m : Type u → Type v} [Monad m] [LawfulMonad m] (x : ExceptT ε m α) (y : ExceptT ε m β) : x <* y = const β <$> x <*> y := by
@@ -188,23 +188,23 @@ theorem ext {x y : StateT σ m α} (h : ∀ s, x.run s = y.run s) : x = y :=
 
 @[simp] theorem run_lift {α σ : Type u} [Monad m] (x : m α) (s : σ) : (StateT.lift x : StateT σ m α).run s = x >>= fun a => pure (a, s) := rfl
 
-theorem run_bind_lift {α σ : Type u} [Monad m] [LawfulMonad m] (x : m α) (f : α → StateT σ m β) (s : σ) : (StateT.lift x >>= f).run s = x >>= fun a => (f a).run s := by
+@[simp] theorem run_bind_lift {α σ : Type u} [Monad m] [LawfulMonad m] (x : m α) (f : α → StateT σ m β) (s : σ) : (StateT.lift x >>= f).run s = x >>= fun a => (f a).run s := by
   simp [StateT.lift, StateT.run, bind, StateT.bind]
 
 @[simp] theorem run_monadLift {α σ : Type u} [Monad m] [MonadLiftT n m] (x : n α) (s : σ) : (monadLift x : StateT σ m α).run s = (monadLift x : m α) >>= fun a => pure (a, s) := rfl
 
-@[simp] theorem run_monadMap [MonadFunctor n m] (f : {β : Type u} → n β → n β) (x : StateT σ m α) (s : σ) :
-    (monadMap @f x : StateT σ m α).run s = monadMap @f (x.run s) := rfl
+@[simp] theorem run_monadMap [Monad m] [MonadFunctor n m] (f : {β : Type u} → n β → n β) (x : StateT σ m α) (s : σ)
+    : (monadMap @f x : StateT σ m α).run s = monadMap @f (x.run s) := rfl
 
 @[simp] theorem run_seq {α β σ : Type u} [Monad m] [LawfulMonad m] (f : StateT σ m (α → β)) (x : StateT σ m α) (s : σ) : (f <*> x).run s = (f.run s >>= fun fs => (fun (p : α × σ) => (fs.1 p.1, p.2)) <$> x.run fs.2) := by
   show (f >>= fun g => g <$> x).run s = _
   simp
 
-@[simp] theorem run_seqRight [Monad m] (x : StateT σ m α) (y : StateT σ m β) (s : σ) : (x *> y).run s = (x.run s >>= fun p => y.run p.2) := by
+@[simp] theorem run_seqRight [Monad m] [LawfulMonad m] (x : StateT σ m α) (y : StateT σ m β) (s : σ) : (x *> y).run s = (x.run s >>= fun p => y.run p.2) := by
   show (x >>= fun _ => y).run s = _
   simp
 
-@[simp] theorem run_seqLeft {α β σ : Type u} [Monad m] (x : StateT σ m α) (y : StateT σ m β) (s : σ) : (x <* y).run s = (x.run s >>= fun p => y.run p.2 >>= fun p' => pure (p.1, p'.2)) := by
+@[simp] theorem run_seqLeft {α β σ : Type u} [Monad m] [LawfulMonad m] (x : StateT σ m α) (y : StateT σ m β) (s : σ) : (x <* y).run s = (x.run s >>= fun p => y.run p.2 >>= fun p' => pure (p.1, p'.2)) := by
   show (x >>= fun a => y >>= fun _ => pure a).run s = _
   simp
 

src/Init/Control/Option.lean

@@ -67,7 +67,7 @@ instance : MonadExceptOf Unit (OptionT m) where
   throw    := fun _ => OptionT.fail
   tryCatch := OptionT.tryCatch
 
-instance (ε : Type u) [MonadExceptOf ε m] : MonadExceptOf ε (OptionT m) where
+instance (ε : Type u) [Monad m] [MonadExceptOf ε m] : MonadExceptOf ε (OptionT m) where
   throw e           := OptionT.mk <| throwThe ε e
   tryCatch x handle := OptionT.mk <| tryCatchThe ε x handle
 

src/Init/Control/Reader.lean

@@ -32,7 +32,7 @@ instance : MonadControl m (ReaderT ρ m) where
   restoreM x _ := x
 
 @[always_inline]
-instance ReaderT.tryFinally [MonadFinally m] : MonadFinally (ReaderT ρ m) where
+instance ReaderT.tryFinally [MonadFinally m] [Monad m] : MonadFinally (ReaderT ρ m) where
   tryFinally' x h ctx := tryFinally' (x ctx) (fun a? => h a? ctx)
 
 @[reducible] def ReaderM (ρ : Type u) := ReaderT ρ Id

src/Init/Control/State.lean

@@ -87,7 +87,7 @@ protected def lift {α : Type u} (t : m α) : StateT σ m α :=
 instance : MonadLift m (StateT σ m) := ⟨StateT.lift⟩
 
 @[always_inline]
-instance (σ m) : MonadFunctor m (StateT σ m) := ⟨fun f x s => f (x s)⟩
+instance (σ m) [Monad m] : MonadFunctor m (StateT σ m) := ⟨fun f x s => f (x s)⟩
 
 @[always_inline]
 instance (ε) [MonadExceptOf ε m] : MonadExceptOf ε (StateT σ m) := {

src/Init/Control/StateCps.lean

@@ -14,18 +14,16 @@ def StateCpsT (σ : Type u) (m : Type u → Type v) (α : Type u) := (δ : Type
 
 namespace StateCpsT
 
-variable {α σ : Type u} {m : Type u → Type v}
-
 @[always_inline, inline]
-def runK (x : StateCpsT σ m α) (s : σ) (k : α → σ → m β) : m β :=
+def runK {α σ : Type u} {m : Type u → Type v}  (x : StateCpsT σ m α) (s : σ) (k : α → σ → m β) : m β :=
   x _ s k
 
 @[always_inline, inline]
-def run [Monad m] (x : StateCpsT σ m α) (s : σ) : m (α × σ) :=
+def run {α σ : Type u} {m : Type u → Type v} [Monad m] (x : StateCpsT σ m α) (s : σ) : m (α × σ) :=
   runK x s (fun a s => pure (a, s))
 
 @[always_inline, inline]
-def run' [Monad m] (x : StateCpsT σ m α) (s : σ) : m α :=
+def run' {α σ : Type u} {m : Type u → Type v}  [Monad m] (x : StateCpsT σ m α) (s : σ) : m α :=
   runK x s (fun a _ => pure a)
 
 @[always_inline]
@@ -35,7 +33,7 @@ instance : Monad (StateCpsT σ m) where
   bind x f := fun δ s k => x δ s fun a s => f a δ s k
 
 instance : LawfulMonad (StateCpsT σ m) := by
-  refine LawfulMonad.mk' _ ?_ ?_ ?_ <;> intros <;> rfl
+  refine' { .. } <;> intros <;> rfl
 
 @[always_inline]
 instance : MonadStateOf σ (StateCpsT σ m) where
@@ -50,29 +48,29 @@ protected def lift [Monad m] (x : m α) : StateCpsT σ m α :=
 instance [Monad m] : MonadLift m (StateCpsT σ m) where
   monadLift := StateCpsT.lift
 
-@[simp] theorem runK_pure (a : α) (s : σ) (k : α → σ → m β) : (pure a : StateCpsT σ m α).runK s k = k a s := rfl
+@[simp] theorem runK_pure {m : Type u → Type v} (a : α) (s : σ) (k : α → σ → m β) : (pure a : StateCpsT σ m α).runK s k = k a s := rfl
 
-@[simp] theorem runK_get (s : σ) (k : σ → σ → m β) : (get : StateCpsT σ m σ).runK s k = k s s := rfl
+@[simp] theorem runK_get {m : Type u → Type v} (s : σ) (k : σ → σ → m β) : (get : StateCpsT σ m σ).runK s k = k s s := rfl
 
-@[simp] theorem runK_set (s s' : σ) (k : PUnit → σ → m β) : (set s' : StateCpsT σ m PUnit).runK s k = k ⟨⟩ s' := rfl
+@[simp] theorem runK_set {m : Type u → Type v} (s s' : σ) (k : PUnit → σ → m β) : (set s' : StateCpsT σ m PUnit).runK s k = k ⟨⟩ s' := rfl
 
-@[simp] theorem runK_modify (f : σ → σ) (s : σ) (k : PUnit → σ → m β) : (modify f : StateCpsT σ m PUnit).runK s k = k ⟨⟩ (f s) := rfl
+@[simp] theorem runK_modify {m : Type u → Type v} (f : σ → σ) (s : σ) (k : PUnit → σ → m β) : (modify f : StateCpsT σ m PUnit).runK s k = k ⟨⟩ (f s) := rfl
 
-@[simp] theorem runK_lift [Monad m] (x : m α) (s : σ) (k : α → σ → m β) : (StateCpsT.lift x : StateCpsT σ m α).runK s k = x >>= (k . s) := rfl
+@[simp] theorem runK_lift {α σ : Type u} [Monad m] (x : m α) (s : σ) (k : α → σ → m β) : (StateCpsT.lift x : StateCpsT σ m α).runK s k = x >>= (k . s) := rfl
 
-@[simp] theorem runK_monadLift [Monad m] [MonadLiftT n m] (x : n α) (s : σ) (k : α → σ → m β)
+@[simp] theorem runK_monadLift {σ : Type u} [Monad m] [MonadLiftT n m] (x : n α) (s : σ) (k : α → σ → m β)
     : (monadLift x : StateCpsT σ m α).runK s k = (monadLift x : m α) >>= (k . s) := rfl
 
-@[simp] theorem runK_bind_pure (a : α) (f : α → StateCpsT σ m β) (s : σ) (k : β → σ → m γ) : (pure a >>= f).runK s k = (f a).runK s k := rfl
+@[simp] theorem runK_bind_pure {α σ : Type u} [Monad m] (a : α) (f : α → StateCpsT σ m β) (s : σ) (k : β → σ → m γ) : (pure a >>= f).runK s k = (f a).runK s k := rfl
 
-@[simp] theorem runK_bind_lift [Monad m] (x : m α) (f : α → StateCpsT σ m β) (s : σ) (k : β → σ → m γ)
+@[simp] theorem runK_bind_lift {α σ : Type u} [Monad m] (x : m α) (f : α → StateCpsT σ m β) (s : σ) (k : β → σ → m γ)
     : (StateCpsT.lift x >>= f).runK s k = x >>= fun a => (f a).runK s k := rfl
 
-@[simp] theorem runK_bind_get (f : σ → StateCpsT σ m β) (s : σ) (k : β → σ → m γ) : (get >>= f).runK s k = (f s).runK s k := rfl
+@[simp] theorem runK_bind_get {σ : Type u} [Monad m] (f : σ → StateCpsT σ m β) (s : σ) (k : β → σ → m γ) : (get >>= f).runK s k = (f s).runK s k := rfl
 
-@[simp] theorem runK_bind_set (f : PUnit → StateCpsT σ m β) (s s' : σ) (k : β → σ → m γ) : (set s' >>= f).runK s k = (f ⟨⟩).runK s' k := rfl
+@[simp] theorem runK_bind_set {σ : Type u} [Monad m] (f : PUnit → StateCpsT σ m β) (s s' : σ) (k : β → σ → m γ) : (set s' >>= f).runK s k = (f ⟨⟩).runK s' k := rfl
 
-@[simp] theorem runK_bind_modify (f : σ → σ) (g : PUnit → StateCpsT σ m β) (s : σ) (k : β → σ → m γ) : (modify f >>= g).runK s k = (g ⟨⟩).runK (f s) k := rfl
+@[simp] theorem runK_bind_modify {σ : Type u} [Monad m] (f : σ → σ) (g : PUnit → StateCpsT σ m β) (s : σ) (k : β → σ → m γ) : (modify f >>= g).runK s k = (g ⟨⟩).runK (f s) k := rfl
 
 @[simp] theorem run_eq [Monad m] (x : StateCpsT σ m α) (s : σ) : x.run s = x.runK s (fun a s => pure (a, s)) := rfl
 

src/Init/Control/StateRef.lean

@@ -34,22 +34,22 @@ protected def lift (x : m α) : StateRefT' ω σ m α :=
 
 instance [Monad m] : Monad (StateRefT' ω σ m) := inferInstanceAs (Monad (ReaderT _ _))
 instance : MonadLift m (StateRefT' ω σ m) := ⟨StateRefT'.lift⟩
-instance (σ m) : MonadFunctor m (StateRefT' ω σ m) := inferInstanceAs (MonadFunctor m (ReaderT _ _))
+instance (σ m) [Monad m] : MonadFunctor m (StateRefT' ω σ m) := inferInstanceAs (MonadFunctor m (ReaderT _ _))
 instance [Alternative m] [Monad m] : Alternative (StateRefT' ω σ m) := inferInstanceAs (Alternative (ReaderT _ _))
 
 @[inline]
-protected def get [MonadLiftT (ST ω) m] : StateRefT' ω σ m σ :=
+protected def get [Monad m] [MonadLiftT (ST ω) m] : StateRefT' ω σ m σ :=
   fun ref => ref.get
 
 @[inline]
-protected def set [MonadLiftT (ST ω) m] (s : σ) : StateRefT' ω σ m PUnit :=
+protected def set [Monad m] [MonadLiftT (ST ω) m] (s : σ) : StateRefT' ω σ m PUnit :=
   fun ref => ref.set s
 
 @[inline]
-protected def modifyGet [MonadLiftT (ST ω) m] (f : σ → α × σ) : StateRefT' ω σ m α :=
+protected def modifyGet [Monad m] [MonadLiftT (ST ω) m] (f : σ → α × σ) : StateRefT' ω σ m α :=
   fun ref => ref.modifyGet f
 
-instance [MonadLiftT (ST ω) m] : MonadStateOf σ (StateRefT' ω σ m) where
+instance [MonadLiftT (ST ω) m] [Monad m] : MonadStateOf σ (StateRefT' ω σ m) where
   get       := StateRefT'.get
   set       := StateRefT'.set
   modifyGet := StateRefT'.modifyGet
@@ -64,5 +64,5 @@ end StateRefT'
 instance (ω σ : Type) (m : Type → Type) : MonadControl m (StateRefT' ω σ m) :=
   inferInstanceAs (MonadControl m (ReaderT _ _))
 
-instance {m : Type → Type} {ω σ : Type} [MonadFinally m] : MonadFinally (StateRefT' ω σ m) :=
+instance {m : Type → Type} {ω σ : Type} [MonadFinally m] [Monad m] : MonadFinally (StateRefT' ω σ m) :=
   inferInstanceAs (MonadFinally (ReaderT _ _))

src/Init/Conv.lean

@@ -97,18 +97,11 @@ Users should prefer `unfold` for unfolding definitions. -/
 syntax (name := delta) "delta" (ppSpace colGt ident)+ : conv
 
 /--
-* `unfold id` unfolds all occurrences of definition `id` in the target.
+* `unfold foo` unfolds all occurrences of `foo` in the target.
 * `unfold id1 id2 ...` is equivalent to `unfold id1; unfold id2; ...`.
-
-Definitions can be either global or local definitions.
-
-For non-recursive global definitions, this tactic is identical to `delta`.
-For recursive global definitions, it uses the "unfolding lemma" `id.eq_def`,
-which is generated for each recursive definition, to unfold according to the recursive definition given by the user.
-Only one level of unfolding is performed, in contrast to `simp only [id]`, which unfolds definition `id` recursively.
-
-This is the `conv` version of the `unfold` tactic.
--/
+Like the `unfold` tactic, this uses equational lemmas for the chosen definition
+to rewrite the target. For recursive definitions,
+only one layer of unfolding is performed. -/
 syntax (name := unfold) "unfold" (ppSpace colGt ident)+ : conv
 
 /--

src/Init/Core.lean

@@ -36,17 +36,6 @@ and `flip (·<·)` is the greater-than relation.
 
 theorem Function.comp_def {α β δ} (f : β → δ) (g : α → β) : f ∘ g = fun x => f (g x) := rfl
 
-@[simp] theorem Function.const_comp {f : α → β} {c : γ} :
-    (Function.const β c ∘ f) = Function.const α c := by
-  rfl
-@[simp] theorem Function.comp_const {f : β → γ} {b : β} :
-    (f ∘ Function.const α b) = Function.const α (f b) := by
-  rfl
-@[simp] theorem Function.true_comp {f : α → β} : ((fun _ => true) ∘ f) = fun _ => true := by
-  rfl
-@[simp] theorem Function.false_comp {f : α → β} : ((fun _ => false) ∘ f) = fun _ => false := by
-  rfl
-
 attribute [simp] namedPattern
 
 /--
@@ -165,23 +154,9 @@ inductive PSum (α : Sort u) (β : Sort v) where
 
 @[inherit_doc] infixr:30 " ⊕' " => PSum
 
-/--
-`PSum α β` is inhabited if `α` is inhabited.
-This is not an instance to avoid non-canonical instances.
--/
-@[reducible] def  PSum.inhabitedLeft {α β} [Inhabited α] : Inhabited (PSum α β) := ⟨PSum.inl default⟩
+instance {α β} [Inhabited α] : Inhabited (PSum α β) := ⟨PSum.inl default⟩
 
-/--
-`PSum α β` is inhabited if `β` is inhabited.
-This is not an instance to avoid non-canonical instances.
--/
-@[reducible] def PSum.inhabitedRight {α β} [Inhabited β] : Inhabited (PSum α β) := ⟨PSum.inr default⟩
-
-instance PSum.nonemptyLeft [h : Nonempty α] : Nonempty (PSum α β) :=
-  Nonempty.elim h (fun a => ⟨PSum.inl a⟩)
-
-instance PSum.nonemptyRight [h : Nonempty β] : Nonempty (PSum α β) :=
-  Nonempty.elim h (fun b => ⟨PSum.inr b⟩)
+instance {α β} [Inhabited β] : Inhabited (PSum α β) := ⟨PSum.inr default⟩
 
 /--
 `Sigma β`, also denoted `Σ a : α, β a` or `(a : α) × β a`, is the type of dependent pairs
@@ -493,13 +468,11 @@ class Singleton (α : outParam <| Type u) (β : Type v) where
 export Singleton (singleton)
 
 /-- `insert x ∅ = {x}` -/
-class LawfulSingleton (α : Type u) (β : Type v) [EmptyCollection β] [Insert α β] [Singleton α β] :
+class IsLawfulSingleton (α : Type u) (β : Type v) [EmptyCollection β] [Insert α β] [Singleton α β] :
     Prop where
   /-- `insert x ∅ = {x}` -/
   insert_emptyc_eq (x : α) : (insert x ∅ : β) = singleton x
-export LawfulSingleton (insert_emptyc_eq)
-
-attribute [simp] insert_emptyc_eq
+export IsLawfulSingleton (insert_emptyc_eq)
 
 /-- Type class used to implement the notation `{ a ∈ c | p a }` -/
 class Sep (α : outParam <| Type u) (γ : Type v) where
@@ -669,7 +642,7 @@ instance : LawfulBEq String := inferInstance
 
 /-! # Logical connectives and equality -/
 
-@[inherit_doc True.intro] theorem trivial : True := ⟨⟩
+@[inherit_doc True.intro] def trivial : True := ⟨⟩
 
 theorem mt {a b : Prop} (h₁ : a → b) (h₂ : ¬b) : ¬a :=
   fun ha => h₂ (h₁ ha)
@@ -728,7 +701,7 @@ theorem Ne.elim (h : a ≠ b) : a = b → False := h
 
 theorem Ne.irrefl (h : a ≠ a) : False := h rfl
 
-@[symm] theorem Ne.symm (h : a ≠ b) : b ≠ a := fun h₁ => h (h₁.symm)
+theorem Ne.symm (h : a ≠ b) : b ≠ a := fun h₁ => h (h₁.symm)
 
 theorem ne_comm {α} {a b : α} : a ≠ b ↔ b ≠ a := ⟨Ne.symm, Ne.symm⟩
 
@@ -781,7 +754,7 @@ noncomputable def HEq.elim {α : Sort u} {a : α} {p : α → Sort v} {b : α} (
 theorem HEq.subst {p : (T : Sort u) → T → Prop} (h₁ : HEq a b) (h₂ : p α a) : p β b :=
   HEq.ndrecOn h₁ h₂
 
-@[symm] theorem HEq.symm (h : HEq a b) : HEq b a :=
+theorem HEq.symm (h : HEq a b) : HEq b a :=
   h.rec (HEq.refl a)
 
 theorem heq_of_eq (h : a = a') : HEq a a' :=
@@ -814,10 +787,10 @@ theorem cast_heq {α β : Sort u} : (h : α = β) → (a : α) → HEq (cast h a
 
 variable {a b c d : Prop}
 
-theorem iff_iff_implies_and_implies {a b : Prop} : (a ↔ b) ↔ (a → b) ∧ (b → a) :=
+theorem iff_iff_implies_and_implies (a b : Prop) : (a ↔ b) ↔ (a → b) ∧ (b → a) :=
   Iff.intro (fun h => And.intro h.mp h.mpr) (fun h => Iff.intro h.left h.right)
 
-@[refl] theorem Iff.refl (a : Prop) : a ↔ a :=
+theorem Iff.refl (a : Prop) : a ↔ a :=
   Iff.intro (fun h => h) (fun h => h)
 
 protected theorem Iff.rfl {a : Prop} : a ↔ a :=
@@ -837,15 +810,15 @@ 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
 
-@[symm] theorem Iff.symm (h : a ↔ b) : b ↔ a := Iff.intro h.mpr h.mp
+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
 
-@[symm] theorem And.symm : a ∧ b → b ∧ a := fun ⟨ha, hb⟩ => ⟨hb, ha⟩
+theorem And.symm : a ∧ b → b ∧ a := fun ⟨ha, hb⟩ => ⟨hb, ha⟩
 theorem And.comm : a ∧ b ↔ b ∧ a := Iff.intro And.symm And.symm
 theorem and_comm : a ∧ b ↔ b ∧ a := And.comm
 
-@[symm] theorem Or.symm : a ∨ b → b ∨ a := .rec .inr .inl
+theorem Or.symm : a ∨ b → b ∨ a := .rec .inr .inl
 theorem Or.comm : a ∨ b ↔ b ∨ a := Iff.intro Or.symm Or.symm
 theorem or_comm : a ∨ b ↔ b ∨ a := Or.comm
 
@@ -910,7 +883,7 @@ theorem byContradiction [dec : Decidable p] (h : ¬p → False) : p :=
 theorem of_not_not [Decidable p] : ¬ ¬ p → p :=
   fun hnn => byContradiction (fun hn => absurd hn hnn)
 
-theorem not_and_iff_or_not {p q : Prop} [d₁ : Decidable p] [d₂ : Decidable q] : ¬ (p ∧ q) ↔ ¬ p ∨ ¬ q :=
+theorem not_and_iff_or_not (p q : Prop) [d₁ : Decidable p] [d₂ : Decidable q] : ¬ (p ∧ q) ↔ ¬ p ∨ ¬ q :=
   Iff.intro
     (fun h => match d₁, d₂ with
       | isTrue h₁,  isTrue h₂   => absurd (And.intro h₁ h₂) h
@@ -1116,30 +1089,19 @@ def InvImage {α : Sort u} {β : Sort v} (r : β → β → Prop) (f : α → β
   fun a₁ a₂ => r (f a₁) (f a₂)
 
 /--
-The transitive closure `TransGen r` of a relation `r` is the smallest relation which is
-transitive and contains `r`. `TransGen r a z` if and only if there exists a sequence
+The transitive closure `r⁺` of a relation `r` is the smallest relation which is
+transitive and contains `r`. `r⁺ a z` if and only if there exists a sequence
 `a r b r ... r z` of length at least 1 connecting `a` to `z`.
 -/
-inductive Relation.TransGen {α : Sort u} (r : α → α → Prop) : α → α → Prop
-  /-- If `r a b` then `TransGen r a b`. This is the base case of the transitive closure. -/
-  | single {a b} : r a b → TransGen r a b
+inductive TC {α : Sort u} (r : α → α → Prop) : α → α → Prop where
+  /-- If `r a b` then `r⁺ a b`. This is the base case of the transitive closure. -/
+  | base  : ∀ a b, r a b → TC r a b
   /-- The transitive closure is transitive. -/
-  | tail {a b c} : TransGen r a b → r b c → TransGen r a c
-
-/-- Deprecated synonym for `Relation.TransGen`. -/
-@[deprecated Relation.TransGen (since := "2024-07-16")] abbrev TC := @Relation.TransGen
-
-theorem Relation.TransGen.trans {α : Sort u} {r : α → α → Prop} {a b c} :
-    TransGen r a b → TransGen r b c → TransGen r a c := by
-  intro hab hbc
-  induction hbc with
-  | single h => exact TransGen.tail hab h
-  | tail _ h ih => exact TransGen.tail ih h
+  | trans : ∀ a b c, TC r a b → TC r b c → TC r a c
 
 /-! # Subtype -/
 
 namespace Subtype
-
 theorem existsOfSubtype {α : Type u} {p : α → Prop} : { x // p x } → Exists (fun x => p x)
   | ⟨a, h⟩ => ⟨a, h⟩
 
@@ -1152,6 +1114,9 @@ theorem eta (a : {x // p x}) (h : p (val a)) : mk (val a) h = a := by
   cases a
   exact rfl
 
+instance {α : Type u} {p : α → Prop} {a : α} (h : p a) : Inhabited {x // p x} where
+  default := ⟨a, h⟩
+
 instance {α : Type u} {p : α → Prop} [DecidableEq α] : DecidableEq {x : α // p x} :=
   fun ⟨a, h₁⟩ ⟨b, h₂⟩ =>
     if h : a = b then isTrue (by subst h; exact rfl)
@@ -1164,20 +1129,12 @@ end Subtype
 section
 variable {α : Type u} {β : Type v}
 
-/-- This is not an instance to avoid non-canonical instances. -/
-@[reducible] def Sum.inhabitedLeft [Inhabited α] : Inhabited (Sum α β) where
+instance Sum.inhabitedLeft [Inhabited α] : Inhabited (Sum α β) where
   default := Sum.inl default
 
-/-- This is not an instance to avoid non-canonical instances. -/
-@[reducible] def Sum.inhabitedRight [Inhabited β] : Inhabited (Sum α β) where
+instance Sum.inhabitedRight [Inhabited β] : Inhabited (Sum α β) where
   default := Sum.inr default
 
-instance Sum.nonemptyLeft [h : Nonempty α] : Nonempty (Sum α β) :=
-  Nonempty.elim h (fun a => ⟨Sum.inl a⟩)
-
-instance Sum.nonemptyRight [h : Nonempty β] : Nonempty (Sum α β) :=
-  Nonempty.elim h (fun b => ⟨Sum.inr b⟩)
-
 instance {α : Type u} {β : Type v} [DecidableEq α] [DecidableEq β] : DecidableEq (Sum α β) := fun a b =>
   match a, b with
   | Sum.inl a, Sum.inl b =>
@@ -1193,21 +1150,6 @@ end
 
 /-! # Product -/
 
-instance [h1 : Nonempty α] [h2 : Nonempty β] : Nonempty (α × β) :=
-  Nonempty.elim h1 fun x =>
-    Nonempty.elim h2 fun y =>
-      ⟨(x, y)⟩
-
-instance [h1 : Nonempty α] [h2 : Nonempty β] : Nonempty (MProd α β) :=
-  Nonempty.elim h1 fun x =>
-    Nonempty.elim h2 fun y =>
-      ⟨⟨x, y⟩⟩
-
-instance [h1 : Nonempty α] [h2 : Nonempty β] : Nonempty (PProd α β) :=
-  Nonempty.elim h1 fun x =>
-    Nonempty.elim h2 fun y =>
-      ⟨⟨x, y⟩⟩
-
 instance [Inhabited α] [Inhabited β] : Inhabited (α × β) where
   default := (default, default)
 
@@ -1234,7 +1176,7 @@ def Prod.lexLt [LT α] [LT β] (s : α × β) (t : α × β) : Prop :=
   s.1 < t.1 ∨ (s.1 = t.1 ∧ s.2 < t.2)
 
 instance Prod.lexLtDec
-    [LT α] [LT β] [DecidableEq α]
+    [LT α] [LT β] [DecidableEq α] [DecidableEq β]
     [(a b : α) → Decidable (a < b)] [(a b : β) → Decidable (a < b)]
     : (s t : α × β) → Decidable (Prod.lexLt s t) :=
   fun _ _ => inferInstanceAs (Decidable (_ ∨ _))
@@ -1252,20 +1194,11 @@ def Prod.map {α₁ : Type u₁} {α₂ : Type u₂} {β₁ : Type v₁} {β₂
     (f : α₁ → α₂) (g : β₁ → β₂) : α₁ × β₁ → α₂ × β₂
   | (a, b) => (f a, g b)
 
-@[simp] theorem Prod.map_apply (f : α → β) (g : γ → δ) (x) (y) :
-    Prod.map f g (x, y) = (f x, g y) := rfl
-@[simp] theorem Prod.map_fst (f : α → β) (g : γ → δ) (x) : (Prod.map f g x).1 = f x.1 := rfl
-@[simp] theorem Prod.map_snd (f : α → β) (g : γ → δ) (x) : (Prod.map f g x).2 = g x.2 := rfl
-
 /-! # Dependent products -/
 
-theorem Exists.of_psigma_prop {α : Sort u} {p : α → Prop} : (PSigma (fun x => p x)) → Exists (fun x => p x)
+theorem ex_of_PSigma {α : Type u} {p : α → Prop} : (PSigma (fun x => p x)) → Exists (fun x => p x)
   | ⟨x, hx⟩ => ⟨x, hx⟩
 
-@[deprecated Exists.of_psigma_prop (since := "2024-07-27")]
-theorem ex_of_PSigma {α : Type u} {p : α → Prop} : (PSigma (fun x => p x)) → Exists (fun x => p x) :=
-  Exists.of_psigma_prop
-
 protected theorem PSigma.eta {α : Sort u} {β : α → Sort v} {a₁ a₂ : α} {b₁ : β a₁} {b₂ : β a₂}
     (h₁ : a₁ = a₂) (h₂ : Eq.ndrec b₁ h₁ = b₂) : PSigma.mk a₁ b₁ = PSigma.mk a₂ b₂ := by
   subst h₁
@@ -1388,7 +1321,7 @@ theorem Nat.succ.inj {m n : Nat} : m.succ = n.succ → m = n :=
 theorem Nat.succ.injEq (u v : Nat) : (u.succ = v.succ) = (u = v) :=
   Eq.propIntro Nat.succ.inj (congrArg Nat.succ)
 
-@[simp] theorem beq_iff_eq [BEq α] [LawfulBEq α] {a b : α} : a == b ↔ a = b :=
+@[simp] theorem beq_iff_eq [BEq α] [LawfulBEq α] (a b : α) : a == b ↔ a = b :=
   ⟨eq_of_beq, by intro h; subst h; exact LawfulBEq.rfl⟩
 
 /-! # Prop lemmas -/
@@ -1427,9 +1360,6 @@ theorem iff_false_right (ha : ¬a) : (b ↔ a) ↔ ¬b := Iff.comm.trans (iff_fa
 theorem of_iff_true    (h : a ↔ True) : a := h.mpr trivial
 theorem iff_true_intro (h : a) : a ↔ True := iff_of_true h trivial
 
-theorem eq_iff_true_of_subsingleton [Subsingleton α] (x y : α) : x = y ↔ True :=
-  iff_true_intro (Subsingleton.elim ..)
-
 theorem not_of_iff_false : (p ↔ False) → ¬p := Iff.mp
 theorem iff_false_intro (h : ¬a) : a ↔ False := iff_of_false h id
 
@@ -1453,7 +1383,7 @@ theorem false_of_true_eq_false  (h : True = False) : False := false_of_true_iff_
 
 theorem true_eq_false_of_false : False → (True = False) := False.elim
 
-theorem iff_def  : (a ↔ b) ↔ (a → b) ∧ (b → a) := iff_iff_implies_and_implies
+theorem iff_def  : (a ↔ b) ↔ (a → b) ∧ (b → a) := iff_iff_implies_and_implies a b
 theorem iff_def' : (a ↔ b) ↔ (b → a) ∧ (a → b) := Iff.trans iff_def And.comm
 
 theorem true_iff_false : (True ↔ False) ↔ False := iff_false_intro (·.mp  True.intro)
@@ -1481,7 +1411,7 @@ theorem imp_true_iff (α : Sort u) : (α → True) ↔ True := iff_true_intro (f
 
 theorem false_imp_iff (a : Prop) : (False → a) ↔ True := iff_true_intro False.elim
 
-theorem true_imp_iff {α : Prop} : (True → α) ↔ α := imp_iff_right True.intro
+theorem true_imp_iff (α : Prop) : (True → α) ↔ α := imp_iff_right True.intro
 
 @[simp high] theorem imp_self : (a → a) ↔ True := iff_true_intro id
 
@@ -1601,13 +1531,13 @@ so you should consider the simpler versions if they apply:
 * `Quot.recOnSubsingleton`, when the target type is a `Subsingleton`
 * `Quot.hrecOn`, which uses `HEq (f a) (f b)` instead of a `sound p ▸ f a = f b` assummption
 -/
-@[elab_as_elim] protected abbrev rec
+protected abbrev rec
     (f : (a : α) → motive (Quot.mk r a))
     (h : (a b : α) → (p : r a b) → Eq.ndrec (f a) (sound p) = f b)
     (q : Quot r) : motive q :=
   Eq.ndrecOn (Quot.liftIndepPr1 f h q) ((lift (Quot.indep f) (Quot.indepCoherent f h) q).2)
 
-@[inherit_doc Quot.rec, elab_as_elim] protected abbrev recOn
+@[inherit_doc Quot.rec] protected abbrev recOn
     (q : Quot r)
     (f : (a : α) → motive (Quot.mk r a))
     (h : (a b : α) → (p : r a b) → Eq.ndrec (f a) (sound p) = f b)
@@ -1618,7 +1548,7 @@ so you should consider the simpler versions if they apply:
 Dependent induction principle for a quotient, when the target type is a `Subsingleton`.
 In this case the quotient's side condition is trivial so any function can be lifted.
 -/
-@[elab_as_elim] protected abbrev recOnSubsingleton
+protected abbrev recOnSubsingleton
     [h : (a : α) → Subsingleton (motive (Quot.mk r a))]
     (q : Quot r)
     (f : (a : α) → motive (Quot.mk r a))
@@ -1687,7 +1617,7 @@ protected theorem ind {α : Sort u} {s : Setoid α} {motive : Quotient s → Pro
 
 /--
 The analogue of `Quot.liftOn`: if `f : α → β` respects the equivalence relation `≈`,
-then it lifts to a function on `Quotient s` such that `liftOn (mk a) f h = f a`.
+then it lifts to a function on `Quotient s` such that `lift (mk a) f h = f a`.
 -/
 protected abbrev liftOn {α : Sort u} {β : Sort v} {s : Setoid α} (q : Quotient s) (f : α → β) (c : (a b : α) → a ≈ b → f a = f b) : β :=
   Quot.liftOn q f c
@@ -1892,8 +1822,7 @@ theorem funext {α : Sort u} {β : α → Sort v} {f g : (x : α) → β x}
   show extfunApp (Quot.mk eqv f) = extfunApp (Quot.mk eqv g)
   exact congrArg extfunApp (Quot.sound h)
 
-instance Pi.instSubsingleton {α : Sort u} {β : α → Sort v} [∀ a, Subsingleton (β a)] :
-    Subsingleton (∀ a, β a) where
+instance {α : Sort u} {β : α → Sort v} [∀ a, Subsingleton (β a)] : Subsingleton (∀ a, β a) where
   allEq f g := funext fun a => Subsingleton.elim (f a) (g a)
 
 /-! # Squash -/
@@ -1936,7 +1865,7 @@ instance : Subsingleton (Squash α) where
 /--
 `Antisymm (·≤·)` says that `(·≤·)` is antisymmetric, that is, `a ≤ b → b ≤ a → a = b`.
 -/
-class Antisymm {α : Sort u} (r : α → α → Prop) : Prop where
+class Antisymm {α : Sort u} (r : α → α → Prop) where
   /-- An antisymmetric relation `(·≤·)` satisfies `a ≤ b → b ≤ a → a = b`. -/
   antisymm {a b : α} : r a b → r b a → a = b
 
@@ -2056,7 +1985,7 @@ class IdempotentOp (op : α → α → α) : Prop where
 `LeftIdentify op o` indicates `o` is a left identity of `op`.
 
 This class does not require a proof that `o` is an identity, and
-is used primarily for inferring the identity using class resolution.
+is used primarily for infering the identity using class resoluton.
 -/
 class LeftIdentity (op : α → β → β) (o : outParam α) : Prop
 
@@ -2072,7 +2001,7 @@ class LawfulLeftIdentity (op : α → β → β) (o : outParam α) extends LeftI
 `RightIdentify op o` indicates `o` is a right identity `o` of `op`.
 
 This class does not require a proof that `o` is an identity, and is used
-primarily for inferring the identity using class resolution.
+primarily for infering the identity using class resoluton.
 -/
 class RightIdentity (op : α → β → α) (o : outParam β) : Prop
 
@@ -2088,7 +2017,7 @@ class LawfulRightIdentity (op : α → β → α) (o : outParam β) extends Righ
 `Identity op o` indicates `o` is a left and right identity of `op`.
 
 This class does not require a proof that `o` is an identity, and is used
-primarily for inferring the identity using class resolution.
+primarily for infering the identity using class resoluton.
 -/
 class Identity (op : α → α → α) (o : outParam α) extends LeftIdentity op o, RightIdentity op o : Prop
 

src/Init/Data.lean

@@ -33,10 +33,5 @@ import Init.Data.Prod
 import Init.Data.AC
 import Init.Data.Queue
 import Init.Data.Channel
+import Init.Data.Cast
 import Init.Data.Sum
-import Init.Data.BEq
-import Init.Data.Subtype
-import Init.Data.ULift
-import Init.Data.PLift
-import Init.Data.Zero
-import Init.Data.NeZero

src/Init/Data/AC.lean

@@ -6,7 +6,7 @@ Authors: Dany Fabian
 
 prelude
 import Init.Classical
-import Init.ByCases
+import Init.Data.List
 
 namespace Lean.Data.AC
 inductive Expr
@@ -146,8 +146,8 @@ theorem Context.evalList_mergeIdem (ctx : Context α) (h : ContextInformation.is
     | nil =>
       simp [mergeIdem, mergeIdem.loop]
       split
-      next h₂ => simp [evalList, h₂, h.1, EvalInformation.evalOp]
-      next => rfl
+      case inl h₂ => simp [evalList, h₂, h.1, EvalInformation.evalOp]
+      rfl
     | cons z zs =>
       by_cases h₂ : x = y
       case pos =>
@@ -191,11 +191,11 @@ theorem Context.evalList_insert
     . simp [evalList, h.1, EvalInformation.evalOp]
   | step y z zs ih =>
     simp [insert] at *; split
-    next => rfl
-    next =>
+    case inl => rfl
+    case inr =>
       split
-      next => simp [evalList, EvalInformation.evalOp]; rw [h.1, ctx.assoc.1, h.1 (evalList _ _ _)]
-      next => simp_all [evalList, EvalInformation.evalOp]; rw [h.1, ctx.assoc.1, h.1 (evalList _ _ _)]
+      case inl => simp [evalList, EvalInformation.evalOp]; rw [h.1, ctx.assoc.1, h.1 (evalList _ _ _)]
+      case inr => simp_all [evalList, EvalInformation.evalOp]; rw [h.1, ctx.assoc.1, h.1 (evalList _ _ _)]
 
 theorem Context.evalList_sort_congr
   (ctx : Context α)
@@ -260,7 +260,7 @@ theorem Context.evalList_sort (ctx : Context α) (h : ContextInformation.isComm
     simp [ContextInformation.isComm, Option.isSome] at h
     match h₂ : ctx.comm with
     | none =>
-      simp [h₂] at h
+      simp only [h₂] at h
     | some val =>
       simp [h₂] at h
       exact val.down

src/Init/Data/Array.lean

@@ -10,9 +10,5 @@ import Init.Data.Array.BinSearch
 import Init.Data.Array.InsertionSort
 import Init.Data.Array.DecidableEq
 import Init.Data.Array.Mem
-import Init.Data.Array.Attach
 import Init.Data.Array.BasicAux
 import Init.Data.Array.Lemmas
-import Init.Data.Array.TakeDrop
-import Init.Data.Array.Bootstrap
-import Init.Data.Array.GetLit

src/Init/Data/Array/Attach.lean

@@ -1,29 +0,0 @@
-/-
-Copyright (c) 2021 Floris van Doorn. All rights reserved.
-Released under Apache 2.0 license as described in the file LICENSE.
-Authors: Joachim Breitner, Mario Carneiro
--/
-prelude
-import Init.Data.Array.Mem
-import Init.Data.List.Attach
-
-namespace Array
-
-/--
-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`.
--/
-@[inline] private unsafe def attachWithImpl
-    (xs : Array α) (P : α → Prop) (_ : ∀ x ∈ xs, P x) : Array {x // P x} := unsafeCast xs
-
-/-- `O(1)`. "Attach" a proof `P x` that holds for all the elements of `xs` to produce a new array
-  with the same elements but in the type `{x // P x}`. -/
-@[implemented_by attachWithImpl] def attachWith
-    (xs : Array α) (P : α → Prop) (H : ∀ x ∈ xs, P x) : Array {x // P x} :=
-  ⟨xs.toList.attachWith P fun x h => H x (Array.Mem.mk h)⟩
-
-/-- `O(1)`. "Attach" the proof that the elements of `xs` are in `xs` to produce a new array
-  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
-
-end Array

src/Init/Data/Array/Basic.lean

@@ -13,18 +13,67 @@ import Init.Data.ToString.Basic
 import Init.GetElem
 universe u v w
 
-/-! ### Array literal syntax -/
-
-syntax "#[" withoutPosition(sepBy(term, ", ")) "]" : term
-
-macro_rules
-  | `(#[ $elems,* ]) => `(List.toArray [ $elems,* ])
-
+namespace Array
 variable {α : Type u}
 
-namespace Array
+@[extern "lean_mk_array"]
+def mkArray {α : Type u} (n : Nat) (v : α) : Array α := {
+  data := List.replicate n v
+}
 
-/-! ### Preliminary theorems -/
+/--
+`ofFn f` with `f : Fin n → α` returns the list whose ith element is `f i`.
+```
+ofFn f = #[f 0, f 1, ... , f(n - 1)]
+``` -/
+def ofFn {n} (f : Fin n → α) : Array α := go 0 (mkEmpty n) where
+  /-- Auxiliary for `ofFn`. `ofFn.go f i acc = acc ++ #[f i, ..., f(n - 1)]` -/
+  go (i : Nat) (acc : Array α) : Array α :=
+    if h : i < n then go (i+1) (acc.push (f ⟨i, h⟩)) else acc
+termination_by n - i
+
+/-- The array `#[0, 1, ..., n - 1]`. -/
+def range (n : Nat) : Array Nat :=
+  n.fold (flip Array.push) (mkEmpty n)
+
+@[simp] theorem size_mkArray (n : Nat) (v : α) : (mkArray n v).size = n :=
+  List.length_replicate ..
+
+instance : EmptyCollection (Array α) := ⟨Array.empty⟩
+instance : Inhabited (Array α) where
+  default := Array.empty
+
+def isEmpty (a : Array α) : Bool :=
+  a.size = 0
+
+def singleton (v : α) : Array α :=
+  mkArray 1 v
+
+/-- Low-level version of `fget` which is as fast as a C array read.
+   `Fin` values are represented as tag pointers in the Lean runtime. Thus,
+   `fget` may be slightly slower than `uget`. -/
+@[extern "lean_array_uget"]
+def uget (a : @& Array α) (i : USize) (h : i.toNat < a.size) : α :=
+  a[i.toNat]
+
+instance : GetElem (Array α) USize α fun xs i => i.toNat < xs.size where
+  getElem xs i h := xs.uget i h
+
+instance : LawfulGetElem (Array α) USize α fun xs i => i.toNat < xs.size where
+
+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.get? (a.size - 1)
+
+-- auxiliary declaration used in the equation compiler when pattern matching array literals.
+abbrev getLit {α : Type u} {n : Nat} (a : Array α) (i : Nat) (h₁ : a.size = n) (h₂ : i < n) : α :=
+  have := h₁.symm ▸ h₂
+  a[i]
 
 @[simp] theorem size_set (a : Array α) (i : Fin a.size) (v : α) : (set a i v).size = a.size :=
   List.length_set ..
@@ -32,71 +81,6 @@ namespace Array
 @[simp] theorem size_push (a : Array α) (v : α) : (push a v).size = a.size + 1 :=
   List.length_concat ..
 
-theorem ext (a b : Array α)
-    (h₁ : a.size = b.size)
-    (h₂ : (i : Nat) → (hi₁ : i < a.size) → (hi₂ : i < b.size) → a[i] = b[i])
-    : a = b := by
-  let rec extAux (a b : List α)
-      (h₁ : a.length = b.length)
-      (h₂ : (i : Nat) → (hi₁ : i < a.length) → (hi₂ : i < b.length) → a.get ⟨i, hi₁⟩ = b.get ⟨i, hi₂⟩)
-      : a = b := by
-    induction a generalizing b with
-    | nil =>
-      cases b with
-      | nil       => rfl
-      | cons b bs => rw [List.length_cons] at h₁; injection h₁
-    | cons a as ih =>
-      cases b with
-      | nil => rw [List.length_cons] at h₁; injection h₁
-      | cons b bs =>
-        have hz₁ : 0 < (a::as).length := by rw [List.length_cons]; apply Nat.zero_lt_succ
-        have hz₂ : 0 < (b::bs).length := by rw [List.length_cons]; apply Nat.zero_lt_succ
-        have headEq : a = b := h₂ 0 hz₁ hz₂
-        have h₁' : as.length = bs.length := by rw [List.length_cons, List.length_cons] at h₁; injection h₁
-        have h₂' : (i : Nat) → (hi₁ : i < as.length) → (hi₂ : i < bs.length) → as.get ⟨i, hi₁⟩ = bs.get ⟨i, hi₂⟩ := by
-          intro i hi₁ hi₂
-          have hi₁' : i+1 < (a::as).length := by rw [List.length_cons]; apply Nat.succ_lt_succ; assumption
-          have hi₂' : i+1 < (b::bs).length := by rw [List.length_cons]; apply Nat.succ_lt_succ; assumption
-          have : (a::as).get ⟨i+1, hi₁'⟩ = (b::bs).get ⟨i+1, hi₂'⟩ := h₂ (i+1) hi₁' hi₂'
-          apply this
-        have tailEq : as = bs := ih bs h₁' h₂'
-        rw [headEq, tailEq]
-  cases a; cases b
-  apply congrArg
-  apply extAux
-  assumption
-  assumption
-
-theorem ext' {as bs : Array α} (h : as.toList = bs.toList) : as = bs := by
-  cases as; cases bs; simp at h; rw [h]
-
-@[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 size_toArray (as : List α) : as.toArray.size = as.length := by simp [size]
-
-@[deprecated toList_toArray (since := "2024-09-09")] abbrev data_toArray := @toList_toArray
-
-@[deprecated Array.toList (since := "2024-09-10")] abbrev Array.data := @Array.toList
-
-/-! ### Externs -/
-
-/-- Low-level version of `size` that directly queries the C array object cached size.
-    While this is not provable, `usize` always returns the exact size of the array since
-    the implementation only supports arrays of size less than `USize.size`.
--/
-@[extern "lean_array_size", simp]
-def usize (a : @& Array α) : USize := a.size.toUSize
-
-/-- Low-level version of `fget` which is as fast as a C array read.
-   `Fin` values are represented as tag pointers in the Lean runtime. Thus,
-   `fget` may be slightly slower than `uget`. -/
-@[extern "lean_array_uget", simp]
-def uget (a : @& Array α) (i : USize) (h : i.toNat < a.size) : α :=
-  a[i.toNat]
-
 /-- Low-level version of `fset` which is as fast as a C array fset.
    `Fin` values are represented as tag pointers in the Lean runtime. Thus,
    `fset` may be slightly slower than `uset`. -/
@@ -104,19 +88,6 @@ def uget (a : @& Array α) (i : USize) (h : i.toNat < a.size) : α :=
 def uset (a : Array α) (i : USize) (v : α) (h : i.toNat < a.size) : Array α :=
   a.set ⟨i.toNat, h⟩ v
 
-@[extern "lean_array_pop"]
-def pop (a : Array α) : Array α where
-  toList := a.toList.dropLast
-
-@[simp] theorem size_pop (a : Array α) : a.pop.size = a.size - 1 := by
-  match a with
-  | ⟨[]⟩ => rfl
-  | ⟨a::as⟩ => simp [pop, Nat.succ_sub_succ_eq_sub, size]
-
-@[extern "lean_mk_array"]
-def mkArray {α : Type u} (n : Nat) (v : α) : Array α where
-  toList := List.replicate n v
-
 /--
 Swaps two entries in an array.
 
@@ -130,12 +101,8 @@ def swap (a : Array α) (i j : @& Fin a.size) : Array α :=
   let a'  := a.set i v₂
   a'.set (size_set a i v₂ ▸ j) v₁
 
-@[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]
-
 /--
-Swaps two entries in an array, or returns the array unchanged if either index is out of bounds.
+Swaps two entries in an array, or panics if either index is out of bounds.
 
 This will perform the update destructively provided that `a` has a reference
 count of 1 when called.
@@ -147,64 +114,6 @@ def swap! (a : Array α) (i j : @& Nat) : Array α :=
   else a
   else a
 
-/-! ### GetElem instance for `USize`, backed by `uget` -/
-
-instance : GetElem (Array α) USize α fun xs i => i.toNat < xs.size where
-  getElem xs i h := xs.uget i h
-
-/-! ### Definitions -/
-
-instance : EmptyCollection (Array α) := ⟨Array.empty⟩
-instance : Inhabited (Array α) where
-  default := Array.empty
-
-@[simp] def isEmpty (a : Array α) : Bool :=
-  a.size = 0
-
-@[specialize]
-def isEqvAux (a b : Array α) (hsz : a.size = b.size) (p : α → α → Bool) :
-    ∀ (i : Nat) (_ : i ≤ a.size), Bool
-  | 0, _ => true
-  | i+1, h =>
-    p a[i] (b[i]'(hsz ▸ h)) && isEqvAux a b hsz p i (Nat.le_trans (Nat.le_add_right i 1) h)
-
-@[inline] def isEqv (a b : Array α) (p : α → α → Bool) : Bool :=
-  if h : a.size = b.size then
-    isEqvAux a b h p a.size (Nat.le_refl a.size)
-  else
-    false
-
-instance [BEq α] : BEq (Array α) :=
-  ⟨fun a b => isEqv a b BEq.beq⟩
-
-/--
-`ofFn f` with `f : Fin n → α` returns the list whose ith element is `f i`.
-```
-ofFn f = #[f 0, f 1, ... , f(n - 1)]
-``` -/
-def ofFn {n} (f : Fin n → α) : Array α := go 0 (mkEmpty n) where
-  /-- Auxiliary for `ofFn`. `ofFn.go f i acc = acc ++ #[f i, ..., f(n - 1)]` -/
-  @[semireducible] -- This is otherwise irreducible because it uses well-founded recursion.
-  go (i : Nat) (acc : Array α) : Array α :=
-    if h : i < n then go (i+1) (acc.push (f ⟨i, h⟩)) else acc
-  decreasing_by simp_wf; decreasing_trivial_pre_omega
-
-/-- The array `#[0, 1, ..., n - 1]`. -/
-def range (n : Nat) : Array Nat :=
-  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.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.get? (a.size - 1)
-
 @[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
@@ -218,6 +127,11 @@ def swapAt! (a : Array α) (i : Nat) (v : α) : α × Array α :=
     have : Inhabited α := ⟨v⟩
     panic! ("index " ++ toString i ++ " out of bounds")
 
+@[extern "lean_array_pop"]
+def pop (a : Array α) : Array α := {
+  data := a.data.dropLast
+}
+
 def shrink (a : Array α) (n : Nat) : Array α :=
   let rec loop
     | 0,   a => a
@@ -261,7 +175,7 @@ def modifyOp (self : Array α) (idx : Nat) (f : α → α) : Array α :=
 
   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 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 sz := USize.ofNat as.size
   let rec @[specialize] loop (i : USize) (b : β) : m β := do
     if i < sz then
       let a := as.uget i lcProof
@@ -367,7 +281,7 @@ def foldrM {α : Type u} {β : Type v} {m : Type v → Type w} [Monad m] (f : α
 /-- 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
+  let sz := USize.ofNat as.size
   let rec @[specialize] map (i : USize) (r : Array NonScalar) : m (Array PNonScalar.{v}) := do
     if i < sz then
      let v    := r.uget i lcProof
@@ -386,13 +300,12 @@ unsafe def mapMUnsafe {α : Type u} {β : Type v} {m : Type v → Type w} [Monad
 def mapM {α : Type u} {β : Type v} {m : Type v → Type w} [Monad m] (f : α → m β) (as : Array α) : m (Array β) :=
   -- Note: we cannot use `foldlM` here for the reference implementation because this calls
   -- `bind` and `pure` too many times. (We are not assuming `m` is a `LawfulMonad`)
-  let rec @[semireducible] -- This is otherwise irreducible because it uses well-founded recursion.
-    map (i : Nat) (r : Array β) : m (Array β) := do
-      if hlt : i < as.size then
-        map (i+1) (r.push (← f as[i]))
-      else
-        pure r
-  decreasing_by simp_wf; decreasing_trivial_pre_omega
+  let rec map (i : Nat) (r : Array β) : m (Array β) := do
+    if hlt : i < as.size then
+      map (i+1) (r.push (← f as[i]))
+    else
+      pure r
+  termination_by as.size - i
   map 0 (mkEmpty as.size)
 
 @[inline]
@@ -455,8 +368,7 @@ unsafe def anyMUnsafe {α : Type u} {m : Type → Type w} [Monad m] (p : α →
 @[implemented_by anyMUnsafe]
 def anyM {α : Type u} {m : Type → Type w} [Monad m] (p : α → m Bool) (as : Array α) (start := 0) (stop := as.size) : m Bool :=
   let any (stop : Nat) (h : stop ≤ as.size) :=
-    let rec @[semireducible] -- This is otherwise irreducible because it uses well-founded recursion.
-    loop (j : Nat) : m Bool := do
+    let rec loop (j : Nat) : m Bool := do
       if hlt : j < stop then
         have : j < as.size := Nat.lt_of_lt_of_le hlt h
         if (← p as[j]) then
@@ -465,7 +377,7 @@ def anyM {α : Type u} {m : Type → Type w} [Monad m] (p : α → m Bool) (as :
           loop (j+1)
       else
         pure false
-      decreasing_by simp_wf; decreasing_trivial_pre_omega
+      termination_by stop - j
     loop start
   if h : stop ≤ as.size then
     any stop h
@@ -546,28 +458,15 @@ def findRev? {α : Type} (as : Array α) (p : α → Bool) : Option α :=
 
 @[inline]
 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) :=
+  let rec loop (j : Nat) :=
     if h : j < as.size then
       if p as[j] then some j else loop (j + 1)
     else none
-    decreasing_by simp_wf; decreasing_trivial_pre_omega
+    termination_by as.size - j
   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
-    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
-
-def indexOf? [BEq α] (a : Array α) (v : α) : Option (Fin a.size) :=
-  indexOfAux a v 0
+a.findIdx? fun a => a == v
 
 @[inline]
 def any (as : Array α) (p : α → Bool) (start := 0) (stop := as.size) : Bool :=
@@ -578,16 +477,23 @@ 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 fun b => a == b
 
 def elem [BEq α] (a : α) (as : Array α) : Bool :=
   as.contains a
 
+@[inline] def getEvenElems (as : Array α) : Array α :=
+  (·.2) <| as.foldl (init := (true, Array.empty)) fun (even, r) a =>
+    if even then
+      (false, r.push a)
+    else
+      (true, r)
+
 /-- Convert a `Array α` into an `List α`. This is O(n) in the size of the array.  -/
--- This function is exported to C, where it is called by `Array.toList`
+-- This function is exported to C, where it is called by `Array.data`
 -- (the projection) to implement this functionality.
-@[export lean_array_to_list_impl]
-def toListImpl (as : Array α) : List α :=
+@[export lean_array_to_list]
+def toList (as : Array α) : List α :=
   as.foldr List.cons []
 
 /-- Prepends an `Array α` onto the front of a list.  Equivalent to `as.toList ++ l`. -/
@@ -595,6 +501,17 @@ def toListImpl (as : Array α) : List α :=
 def toListAppend (as : Array α) (l : List α) : List α :=
   as.foldr List.cons l
 
+instance {α : Type u} [Repr α] : Repr (Array α) where
+  reprPrec a _ :=
+    let _ : Std.ToFormat α := ⟨repr⟩
+    if a.size == 0 then
+      "#[]"
+    else
+      Std.Format.bracketFill "#[" (Std.Format.joinSep (toList a) ("," ++ Std.Format.line)) "]"
+
+instance [ToString α] : ToString (Array α) where
+  toString a := "#" ++ toString a.toList
+
 protected def append (as : Array α) (bs : Array α) : Array α :=
   bs.foldl (init := as) fun r v => r.push v
 
@@ -620,13 +537,43 @@ def concatMap (f : α → Array β) (as : Array α) : Array β :=
 def flatten (as : Array (Array α)) : Array α :=
   as.foldl (init := empty) fun r a => r ++ a
 
+end Array
+
+export Array (mkArray)
+
+syntax "#[" withoutPosition(sepBy(term, ", ")) "]" : term
+
+macro_rules
+  | `(#[ $elems,* ]) => `(List.toArray [ $elems,* ])
+
+namespace Array
+
+-- TODO(Leo): cleanup
+@[specialize]
+def isEqvAux (a b : Array α) (hsz : a.size = b.size) (p : α → α → Bool) (i : Nat) : Bool :=
+  if h : i < a.size then
+     have : i < b.size := hsz ▸ h
+     p a[i] b[i] && isEqvAux a b hsz p (i+1)
+  else
+    true
+termination_by a.size - i
+
+@[inline] def isEqv (a b : Array α) (p : α → α → Bool) : Bool :=
+  if h : a.size = b.size then
+    isEqvAux a b h p 0
+  else
+    false
+
+instance [BEq α] : BEq (Array α) :=
+  ⟨fun a b => isEqv a b BEq.beq⟩
+
 @[inline]
 def filter (p : α → Bool) (as : Array α) (start := 0) (stop := as.size) : Array α :=
   as.foldl (init := #[]) (start := start) (stop := stop) fun r a =>
     if p a then r.push a else r
 
 @[inline]
-def filterM {α : Type} [Monad m] (p : α → m Bool) (as : Array α) (start := 0) (stop := as.size) : m (Array α) :=
+def filterM [Monad m] (p : α → m Bool) (as : Array α) (start := 0) (stop := as.size) : m (Array α) :=
   as.foldlM (init := #[]) (start := start) (stop := stop) fun r a => do
     if (← p a) then return r.push a else return r
 
@@ -661,25 +608,92 @@ def partition (p : α → Bool) (as : Array α) : Array α × Array α := Id.run
       cs := cs.push a
   return (bs, cs)
 
+theorem ext (a b : Array α)
+    (h₁ : a.size = b.size)
+    (h₂ : (i : Nat) → (hi₁ : i < a.size) → (hi₂ : i < b.size) → a[i] = b[i])
+    : a = b := by
+  let rec extAux (a b : List α)
+      (h₁ : a.length = b.length)
+      (h₂ : (i : Nat) → (hi₁ : i < a.length) → (hi₂ : i < b.length) → a.get ⟨i, hi₁⟩ = b.get ⟨i, hi₂⟩)
+      : a = b := by
+    induction a generalizing b with
+    | nil =>
+      cases b with
+      | nil       => rfl
+      | cons b bs => rw [List.length_cons] at h₁; injection h₁
+    | cons a as ih =>
+      cases b with
+      | nil => rw [List.length_cons] at h₁; injection h₁
+      | cons b bs =>
+        have hz₁ : 0 < (a::as).length := by rw [List.length_cons]; apply Nat.zero_lt_succ
+        have hz₂ : 0 < (b::bs).length := by rw [List.length_cons]; apply Nat.zero_lt_succ
+        have headEq : a = b := h₂ 0 hz₁ hz₂
+        have h₁' : as.length = bs.length := by rw [List.length_cons, List.length_cons] at h₁; injection h₁
+        have h₂' : (i : Nat) → (hi₁ : i < as.length) → (hi₂ : i < bs.length) → as.get ⟨i, hi₁⟩ = bs.get ⟨i, hi₂⟩ := by
+          intro i hi₁ hi₂
+          have hi₁' : i+1 < (a::as).length := by rw [List.length_cons]; apply Nat.succ_lt_succ; assumption
+          have hi₂' : i+1 < (b::bs).length := by rw [List.length_cons]; apply Nat.succ_lt_succ; assumption
+          have : (a::as).get ⟨i+1, hi₁'⟩ = (b::bs).get ⟨i+1, hi₂'⟩ := h₂ (i+1) hi₁' hi₂'
+          apply this
+        have tailEq : as = bs := ih bs h₁' h₂'
+        rw [headEq, tailEq]
+  cases a; cases b
+  apply congrArg
+  apply extAux
+  assumption
+  assumption
+
+theorem extLit {n : Nat}
+    (a b : Array α)
+    (hsz₁ : a.size = n) (hsz₂ : b.size = n)
+    (h : (i : Nat) → (hi : i < n) → a.getLit i hsz₁ hi = b.getLit i hsz₂ hi) : a = b :=
+  Array.ext a b (hsz₁.trans hsz₂.symm) fun i hi₁ _ => h i (hsz₁ ▸ hi₁)
+
+end Array
+
+-- CLEANUP the following code
+namespace Array
+
+def indexOfAux [BEq α] (a : Array α) (v : α) (i : Nat) : Option (Fin a.size) :=
+  if h : i < a.size then
+    let idx : Fin a.size := ⟨i, h⟩;
+    if a.get idx == v then some idx
+    else indexOfAux a v (i+1)
+  else none
+termination_by a.size - i
+
+def indexOf? [BEq α] (a : Array α) (v : α) : Option (Fin a.size) :=
+  indexOfAux a v 0
+
+@[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]
+
+@[simp] theorem size_pop (a : Array α) : a.pop.size = a.size - 1 := by
+  match a with
+  | ⟨[]⟩ => rfl
+  | ⟨a::as⟩ => simp [pop, Nat.succ_sub_succ_eq_sub, size]
+
+theorem reverse.termination {i j : Nat} (h : i < j) : j - 1 - (i + 1) < j - i := by
+  rw [Nat.sub_sub, Nat.add_comm]
+  exact Nat.lt_of_le_of_lt (Nat.pred_le _) (Nat.sub_succ_lt_self _ _ h)
+
 def reverse (as : Array α) : Array α :=
   if h : as.size ≤ 1 then
     as
   else
     loop as 0 ⟨as.size - 1, Nat.pred_lt (mt (fun h : as.size = 0 => h ▸ by decide) h)⟩
 where
-  termination {i j : Nat} (h : i < j) : j - 1 - (i + 1) < j - i := by
-    rw [Nat.sub_sub, Nat.add_comm]
-    exact Nat.lt_of_le_of_lt (Nat.pred_le _) (Nat.sub_succ_lt_self _ _ h)
   loop (as : Array α) (i : Nat) (j : Fin as.size) :=
     if h : i < j then
-      have := termination h
+      have := reverse.termination h
       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
       as
+termination_by j - i
 
-@[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.get ⟨as.size - 1, Nat.sub_lt h (by decide)⟩) then
@@ -688,11 +702,10 @@ def popWhile (p : α → Bool) (as : Array α) : Array α :=
       as
   else
     as
-decreasing_by simp_wf; decreasing_trivial_pre_omega
+termination_by as.size
 
 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 :=
+  let rec go (i : Nat) (r : Array α) : Array α :=
     if h : i < as.size then
       let a := as.get ⟨i, h⟩
       if p a then
@@ -701,28 +714,27 @@ def takeWhile (p : α → Bool) (as : Array α) : Array α :=
         r
     else
       r
-    decreasing_by simp_wf; decreasing_trivial_pre_omega
+    termination_by as.size - i
   go 0 #[]
 
 /-- 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`.-/
-@[semireducible] -- This is otherwise irreducible because it uses well-founded recursion.
 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]⟩
+    have : a'.size - i' < a.size - i := by
+      simp [a', Nat.sub_succ_lt_self _ _ i.isLt]
     a'.feraseIdx i'
   else
     a.pop
 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`.
 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 =>
+  | @case1 a i h a' _ _ ih =>
     unfold feraseIdx
     simp [h, a', ih]
   | case2 a i h =>
@@ -743,15 +755,14 @@ def erase [BEq α] (as : Array α) (a : α) : Array α :=
 
 /-- Insert element `a` at position `i`. -/
 @[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) :=
+  let rec loop (as : Array α) (j : Fin as.size) :=
     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
       as
-    decreasing_by simp_wf; decreasing_trivial_pre_omega
+    termination_by j.1
   let j := as.size
   let as := as.push a
   loop as ⟨j, size_push .. ▸ j.lt_succ_self⟩
@@ -762,7 +773,37 @@ def insertAt! (as : Array α) (i : Nat) (a : α) : Array α :=
     insertAt as ⟨i, Nat.lt_succ_of_le h⟩ a
   else panic! "invalid index"
 
-@[semireducible] -- This is otherwise irreducible because it uses well-founded recursion.
+def toListLitAux (a : Array α) (n : Nat) (hsz : a.size = n) : ∀ (i : Nat), i ≤ a.size → List α → List α
+  | 0,     _,  acc => acc
+  | (i+1), hi, acc => toListLitAux a n hsz i (Nat.le_of_succ_le hi) (a.getLit i hsz (Nat.lt_of_lt_of_eq (Nat.lt_of_lt_of_le (Nat.lt_succ_self i) hi) hsz) :: acc)
+
+def toArrayLit (a : Array α) (n : Nat) (hsz : a.size = n) : Array α :=
+  List.toArray <| toListLitAux a n hsz n (hsz ▸ Nat.le_refl _) []
+
+theorem ext' {as bs : Array α} (h : as.data = bs.data) : as = bs := by
+  cases as; cases bs; simp at h; rw [h]
+
+theorem toArrayAux_eq (as : List α) (acc : Array α) : (as.toArrayAux acc).data = acc.data ++ as := by
+  induction as generalizing acc <;> simp [*, List.toArrayAux, Array.push, List.append_assoc, List.concat_eq_append]
+
+theorem data_toArray (as : List α) : as.toArray.data = as := by
+  simp [List.toArray, toArrayAux_eq, Array.mkEmpty]
+
+theorem toArrayLit_eq (as : Array α) (n : Nat) (hsz : as.size = n) : as = toArrayLit as n hsz := by
+  apply ext'
+  simp [toArrayLit, data_toArray]
+  have hle : n ≤ as.size := hsz ▸ Nat.le_refl _
+  have hge : as.size ≤ n := hsz ▸ Nat.le_refl _
+  have := go n hle
+  rw [List.drop_eq_nil_of_le hge] at this
+  rw [this]
+where
+  getLit_eq (as : Array α) (i : Nat) (h₁ : as.size = n) (h₂ : i < n) : as.getLit i h₁ h₂ = getElem as.data i ((id (α := as.data.length = n) h₁) ▸ h₂) :=
+    rfl
+
+  go (i : Nat) (hi : i ≤ as.size) : toListLitAux as n hsz i hi (as.data.drop i) = as.data := by
+    induction i <;> simp [getLit_eq, List.get_drop_eq_drop, toListLitAux, List.drop, *]
+
 def isPrefixOfAux [BEq α] (as bs : Array α) (hle : as.size ≤ bs.size) (i : Nat) : Bool :=
   if h : i < as.size then
     let a := as[i]
@@ -774,7 +815,7 @@ def isPrefixOfAux [BEq α] (as bs : Array α) (hle : as.size ≤ bs.size) (i : N
       false
   else
     true
-decreasing_by simp_wf; decreasing_trivial_pre_omega
+termination_by as.size - i
 
 /-- Return true iff `as` is a prefix of `bs`.
 That is, `bs = as ++ t` for some `t : List α`.-/
@@ -784,8 +825,23 @@ def isPrefixOf [BEq α] (as bs : Array α) : Bool :=
   else
     false
 
-@[semireducible, specialize] -- This is otherwise irreducible because it uses well-founded recursion.
-def zipWithAux (f : α → β → γ) (as : Array α) (bs : Array β) (i : Nat) (cs : Array γ) : Array γ :=
+private def allDiffAuxAux [BEq α] (as : Array α) (a : α) : forall (i : Nat), i < as.size → Bool
+  | 0,   _ => true
+  | i+1, h =>
+    have : i < as.size := Nat.lt_trans (Nat.lt_succ_self _) h;
+    a != as[i] && allDiffAuxAux as a i this
+
+private def allDiffAux [BEq α] (as : Array α) (i : Nat) : Bool :=
+  if h : i < as.size then
+    allDiffAuxAux as as[i] i h && allDiffAux as (i+1)
+  else
+    true
+termination_by as.size - i
+
+def allDiff [BEq α] (as : Array α) : Bool :=
+  allDiffAux as 0
+
+@[specialize] 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
@@ -795,7 +851,7 @@ def zipWithAux (f : α → β → γ) (as : Array α) (bs : Array β) (i : Nat)
       cs
   else
     cs
-decreasing_by simp_wf; decreasing_trivial_pre_omega
+termination_by as.size - i
 
 @[inline] def zipWith (as : Array α) (bs : Array β) (f : α → β → γ) : Array γ :=
   zipWithAux f as bs 0 #[]
@@ -810,48 +866,4 @@ 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.
-
-We do not intend to provide verification theorems for these functions.
--/
-
-private def allDiffAuxAux [BEq α] (as : Array α) (a : α) : forall (i : Nat), i < as.size → Bool
-  | 0,   _ => true
-  | i+1, h =>
-    have : i < as.size := Nat.lt_trans (Nat.lt_succ_self _) h;
-    a != as[i] && allDiffAuxAux as a i this
-
-@[semireducible] -- This is otherwise irreducible because it uses well-founded recursion.
-private def allDiffAux [BEq α] (as : Array α) (i : Nat) : Bool :=
-  if h : i < as.size then
-    allDiffAuxAux as as[i] i h && allDiffAux as (i+1)
-  else
-    true
-decreasing_by simp_wf; decreasing_trivial_pre_omega
-
-def allDiff [BEq α] (as : Array α) : Bool :=
-  allDiffAux as 0
-
-@[inline] def getEvenElems (as : Array α) : Array α :=
-  (·.2) <| as.foldl (init := (true, Array.empty)) fun (even, r) a =>
-    if even then
-      (false, r.push a)
-    else
-      (true, r)
-
-/-! ### Repr and ToString -/
-
-instance {α : Type u} [Repr α] : Repr (Array α) where
-  reprPrec a _ :=
-    let _ : Std.ToFormat α := ⟨repr⟩
-    if a.size == 0 then
-      "#[]"
-    else
-      Std.Format.bracketFill "#[" (Std.Format.joinSep (toList a) ("," ++ Std.Format.line)) "]"
-
-instance [ToString α] : ToString (Array α) where
-  toString a := "#" ++ toString a.toList
-
 end Array
-
-export Array (mkArray)

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 [push] at h
   have ⟨h₁, h₂⟩ := List.of_concat_eq_concat h
   cases as; cases bs
   simp_all
@@ -34,11 +34,11 @@ 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 } :=
-  go 0 ⟨mkEmpty as.size, rfl⟩ (by simp)
+  go 0 ⟨mkEmpty as.size, rfl⟩ (by simp_arith)
 where
   go (i : Nat) (acc : { bs : Array β // bs.size = i }) (hle : i ≤ as.size) : m { bs : Array β // bs.size = as.size } := do
     if h : i = as.size then
@@ -48,7 +48,6 @@ where
       let b ← f as[i]
       go (i+1) ⟨acc.val.push b, by simp [acc.property]⟩ hlt
   termination_by as.size - i
-  decreasing_by decreasing_trivial_pre_omega
 
 @[inline] private unsafe def mapMonoMImp [Monad m] (as : Array α) (f : α → m α) : m (Array α) :=
   go 0 as

src/Init/Data/Array/Bootstrap.lean

@@ -1,120 +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
--/
-
-prelude
-import Init.Data.List.TakeDrop
-
-/-!
-## Bootstrapping theorems about arrays
-
-This file contains some theorems about `Array` and `List` needed for `Init.Data.List.Impl`.
--/
-
-namespace Array
-
-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_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
-
-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 [foldlM, foldlM_eq_foldlM_toList.aux]
-
-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) :
-    (arr.toList.take i).reverse.foldlM (fun x y => f y x) init = foldrM.fold f arr 0 i h init := by
-  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)]; 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
-  have : arr = #[] ∨ 0 < arr.size :=
-    match arr with | ⟨[]⟩ => .inl rfl | ⟨a::l⟩ => .inr (Nat.zero_lt_succ _)
-  match arr, this with | _, .inl rfl => rfl | arr, .inr h => ?_
-  simp [foldrM, h, ← foldrM_eq_reverse_foldlM_toList.aux, List.take_length]
-
-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
-  rw [foldrM_eq_reverse_foldlM_toList, List.foldlM_reverse]
-
-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_eq_foldr_toList]
-
-@[simp] theorem toListImpl_eq (arr : Array α) : arr.toListImpl = arr.toList := by
-  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 append_toList (arr arr' : Array α) :
-    (arr ++ arr').toList = arr.toList ++ arr'.toList := by
-  rw [← append_eq_append]; unfold Array.append
-  rw [foldl_eq_foldl_toList]
-  induction arr'.toList generalizing arr <;> simp [*]
-
-@[simp] theorem appendList_eq_append
-    (arr : Array α) (l : List α) : arr.appendList l = arr ++ l := rfl
-
-@[simp] theorem appendList_toList (arr : Array α) (l : List α) :
-    (arr ++ l).toList = arr.toList ++ l := by
-  rw [← appendList_eq_append]; unfold Array.appendList
-  induction l generalizing arr <;> simp [*]
-
-@[deprecated foldlM_eq_foldlM_toList (since := "2024-09-09")]
-abbrev foldlM_eq_foldlM_data := @foldlM_eq_foldlM_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_eq_foldrM_toList (since := "2024-09-09")]
-abbrev foldrM_eq_foldrM_data := @foldrM_eq_foldrM_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
-
-@[deprecated toListImpl_eq (since := "2024-09-09")]
-abbrev toList_eq := @toListImpl_eq
-
-@[deprecated pop_toList (since := "2024-09-09")]
-abbrev pop_data := @pop_toList
-
-@[deprecated append_toList (since := "2024-09-09")]
-abbrev append_data := @append_toList
-
-@[deprecated appendList_toList (since := "2024-09-09")]
-abbrev appendList_data := @appendList_toList
-
-end Array

src/Init/Data/Array/DecidableEq.lean

@@ -5,49 +5,40 @@ Authors: Leonardo de Moura
 -/
 prelude
 import Init.Data.Array.Basic
-import Init.Data.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)
-    (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
-  induction i with
-  | zero => contradiction
-  | succ i ih =>
-    simp only [Array.isEqvAux, Bool.and_eq_true, decide_eq_true_eq] at heqv
-    by_cases hj' : j < i
-    next =>
-      exact ih _ heqv.right hj'
-    next =>
-      replace hj' : j = i := Nat.eq_of_le_of_lt_succ (Nat.not_lt.mp hj') hj
-      subst hj'
-      exact heqv.left
+theorem eq_of_isEqvAux [DecidableEq α] (a b : Array α) (hsz : a.size = b.size) (i : Nat) (hi : i ≤ a.size) (heqv : Array.isEqvAux a b hsz (fun x y => x = y) i) (j : Nat) (low : i ≤ j) (high : j < a.size) : a[j] = b[j]'(hsz ▸ high) := by
+  by_cases h : i < a.size
+  · unfold Array.isEqvAux at heqv
+    simp [h] at heqv
+    have hind := eq_of_isEqvAux a b hsz (i+1) (Nat.succ_le_of_lt h) heqv.2
+    by_cases heq : i = j
+    · subst heq; exact heqv.1
+    · exact hind j (Nat.succ_le_of_lt (Nat.lt_of_le_of_ne low heq)) high
+  · have heq : i = a.size := Nat.le_antisymm hi (Nat.ge_of_not_lt h)
+    subst heq
+    exact absurd (Nat.lt_of_lt_of_le high low) (Nat.lt_irrefl j)
+termination_by a.size - i
 
-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, rel_of_isEqvAux r a b h a.size (Nat.le_refl ..) h'⟩
-  · intro; contradiction
+theorem eq_of_isEqv [DecidableEq α] (a b : Array α) : Array.isEqv a b (fun x y => x = y) → a = b := by
+  simp [Array.isEqv]
+  split
+  case inr => intro; contradiction
+  case inl hsz =>
+   intro h
+   have aux := eq_of_isEqvAux a b hsz 0 (Nat.zero_le ..) h
+   exact ext a b hsz fun i h _ => aux i (Nat.zero_le ..) _
 
-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 (fun x y => x = y) a b h
-  exact ext _ _ h (fun i lt _ => by simpa using h' i lt)
+theorem isEqvAux_self [DecidableEq α] (a : Array α) (i : Nat) : Array.isEqvAux a a rfl (fun x y => x = y) i = true := by
+  unfold Array.isEqvAux
+  split
+  case inl h => simp [h, isEqvAux_self a (i+1)]
+  case inr h => simp [h]
+termination_by a.size - i
 
-theorem isEqvAux_self (r : α → α → Bool) (hr : ∀ a, r a a) (a : Array α) (i : Nat) (h : i ≤ a.size) :
-    Array.isEqvAux a a rfl r i h = true := by
-  induction i with
-  | zero => simp [Array.isEqvAux]
-  | succ i ih =>
-    simp_all only [isEqvAux, Bool.and_self]
-
-theorem isEqv_self_beq [BEq α] [ReflBEq α] (a : Array α) : Array.isEqv a a (· == ·) = true := by
-  simp [isEqv, isEqvAux_self]
-
-theorem isEqv_self [DecidableEq α] (a : Array α) : Array.isEqv a a (· = ·) = true := by
+theorem isEqv_self [DecidableEq α] (a : Array α) : Array.isEqv a a (fun x y => x = y) = true := by
   simp [isEqv, isEqvAux_self]
 
 instance [DecidableEq α] : DecidableEq (Array α) :=

src/Init/Data/Array/GetLit.lean

@@ -1,46 +0,0 @@
-/-
-Copyright (c) 2018 Microsoft Corporation. All rights reserved.
-Released under Apache 2.0 license as described in the file LICENSE.
-Authors: Leonardo de Moura
--/
-
-prelude
-import Init.Data.Array.Basic
-
-namespace Array
-
-/-! ### getLit -/
-
--- auxiliary declaration used in the equation compiler when pattern matching array literals.
-abbrev getLit {α : Type u} {n : Nat} (a : Array α) (i : Nat) (h₁ : a.size = n) (h₂ : i < n) : α :=
-  have := h₁.symm ▸ h₂
-  a[i]
-
-theorem extLit {n : Nat}
-    (a b : Array α)
-    (hsz₁ : a.size = n) (hsz₂ : b.size = n)
-    (h : (i : Nat) → (hi : i < n) → a.getLit i hsz₁ hi = b.getLit i hsz₂ hi) : a = b :=
-  Array.ext a b (hsz₁.trans hsz₂.symm) fun i hi₁ _ => h i (hsz₁ ▸ hi₁)
-
-def toListLitAux (a : Array α) (n : Nat) (hsz : a.size = n) : ∀ (i : Nat), i ≤ a.size → List α → List α
-  | 0,     _,  acc => acc
-  | (i+1), hi, acc => toListLitAux a n hsz i (Nat.le_of_succ_le hi) (a.getLit i hsz (Nat.lt_of_lt_of_eq (Nat.lt_of_lt_of_le (Nat.lt_succ_self i) hi) hsz) :: acc)
-
-def toArrayLit (a : Array α) (n : Nat) (hsz : a.size = n) : Array α :=
-  List.toArray <| toListLitAux a n hsz n (hsz ▸ Nat.le_refl _) []
-
-theorem toArrayLit_eq (as : Array α) (n : Nat) (hsz : as.size = n) : as = toArrayLit as n hsz := by
-  apply ext'
-  simp [toArrayLit, toList_toArray]
-  have hle : n ≤ as.size := hsz ▸ Nat.le_refl _
-  have hge : as.size ≤ n := hsz ▸ Nat.le_refl _
-  have := go n hle
-  rw [List.drop_eq_nil_of_le hge] at this
-  rw [this]
-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 [getLit_eq, List.get_drop_eq_drop, toListLitAux, List.drop, *]
-
-end Array

src/Init/Data/Array/Mem.lean

@@ -13,34 +13,27 @@ 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
+structure Mem (a : α) (as : Array α) : Prop where
+  val : a ∈ as.data
 
 instance : Membership α (Array α) where
-  mem := Mem
+  mem a as := Mem a as
 
 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 : Fin as.size) : sizeOf (as.get i) < sizeOf as := by
+@[simp] theorem sizeOf_get [SizeOf α] (as : Array α) (i : Fin as.size) : sizeOf (as.get i) < sizeOf as := by
   cases as with | _ as =>
   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 _ _
-
 /-- This tactic, added to the `decreasing_trivial` toolbox, proves that
 `sizeOf arr[i] < sizeOf arr`, which is useful for well founded recursions
 over a nested inductive like `inductive T | mk : Array T → T`. -/
 macro "array_get_dec" : tactic =>
   `(tactic| first
-    -- subsumed by simp
-    -- | with_reducible apply sizeOf_get
-    -- | with_reducible apply sizeOf_getElem
-    | (with_reducible apply Nat.lt_of_lt_of_le (sizeOf_get ..)); simp_arith
-    | (with_reducible apply Nat.lt_of_lt_of_le (sizeOf_getElem ..)); simp_arith
-    )
+    | apply sizeOf_get
+    | apply Nat.lt_trans (sizeOf_get ..); simp_arith)
 
 macro_rules | `(tactic| decreasing_trivial) => `(tactic| array_get_dec)
 
@@ -50,10 +43,9 @@ provided that `a ∈ arr` which is useful for well founded recursions over a nes
 -- NB: This is analogue to tactic `sizeOf_list_dec`
 macro "array_mem_dec" : tactic =>
   `(tactic| first
-    | with_reducible apply Array.sizeOf_lt_of_mem; assumption; done
-    | with_reducible
-        apply Nat.lt_of_lt_of_le (Array.sizeOf_lt_of_mem ?h)
-        case' h => assumption
+    | apply Array.sizeOf_lt_of_mem; assumption; done
+    | apply Nat.lt_trans (Array.sizeOf_lt_of_mem ?h)
+      case' h => assumption
       simp_arith)
 
 macro_rules | `(tactic| decreasing_trivial) => `(tactic| array_mem_dec)

src/Init/Data/Array/QSort.lean

@@ -27,7 +27,6 @@ def qpartition (as : Array α) (lt : α → α → Bool) (lo hi : Nat) : Nat ×
       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] partial def qsort (as : Array α) (lt : α → α → Bool) (low := 0) (high := as.size - 1) : Array α :=

src/Init/Data/Array/Subarray.lean

@@ -15,14 +15,14 @@ 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")]
+@[deprecated Subarray.array]
 abbrev Subarray.as (s : Subarray α) : Array α := s.array
 
-@[deprecated Subarray.start_le_stop (since := "2024-04-13")]
+@[deprecated Subarray.start_le_stop]
 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
+@[deprecated Subarray.stop_le_array_size]
+theorem Subarray.h₂ (s : Subarray α) : s.stop ≤ s.as.size := s.stop_le_array_size
 
 namespace Subarray
 
@@ -47,6 +47,8 @@ def get (s : Subarray α) (i : Fin s.size) : α :=
 instance : GetElem (Subarray α) Nat α fun xs i => i < xs.size where
   getElem xs i h := xs.get ⟨i, h⟩
 
+instance : LawfulGetElem (Subarray α) Nat α fun xs i => i < xs.size where
+
 @[inline] def getD (s : Subarray α) (i : Nat) (v₀ : α) : α :=
   if h : i < s.size then s.get ⟨i, h⟩ else v₀
 

src/Init/Data/Array/TakeDrop.lean

@@ -1,18 +0,0 @@
-/-
-Copyright (c) 2024 Lean FRO, LLC. All rights reserved.
-Released under Apache 2.0 license as described in the file LICENSE.
-Authors: Markus Himmel
--/
-prelude
-import Init.Data.Array.Lemmas
-import Init.Data.List.Nat.TakeDrop
-
-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_eq_toList_getElem, uset, toList_set] using
-    List.exists_of_set _
-
-end Array

src/Init/Data/BEq.lean

@@ -1,60 +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, Markus Himmel
--/
-prelude
-import Init.Data.Bool
-
-set_option linter.missingDocs true
-
-/-- `PartialEquivBEq α` says that the `BEq` implementation is a
-partial equivalence relation, that is:
-* it is symmetric: `a == b → b == a`
-* it is transitive: `a == b → b == c → a == c`.
--/
-class PartialEquivBEq (α) [BEq α] : Prop where
-  /-- Symmetry for `BEq`. If `a == b` then `b == a`. -/
-  symm : (a : α) == b → b == a
-  /-- Transitivity for `BEq`. If `a == b` and `b == c` then `a == c`. -/
-  trans : (a : α) == b → b == c → a == c
-
-/-- `ReflBEq α` says that the `BEq` implementation is reflexive. -/
-class ReflBEq (α) [BEq α] : Prop where
-  /-- Reflexivity for `BEq`. -/
-  refl : (a : α) == a
-
-/-- `EquivBEq` says that the `BEq` implementation is an equivalence relation. -/
-class EquivBEq (α) [BEq α] extends PartialEquivBEq α, ReflBEq α : Prop
-
-@[simp]
-theorem BEq.refl [BEq α] [ReflBEq α] {a : α} : a == a :=
-  ReflBEq.refl
-
-theorem beq_of_eq [BEq α] [ReflBEq α] {a b : α} : a = b → a == b
-  | rfl => BEq.refl
-
-theorem BEq.symm [BEq α] [PartialEquivBEq α] {a b : α} : a == b → b == a :=
-  PartialEquivBEq.symm
-
-theorem BEq.comm [BEq α] [PartialEquivBEq α] {a b : α} : (a == b) = (b == a) :=
-  Bool.eq_iff_iff.2 ⟨BEq.symm, BEq.symm⟩
-
-theorem BEq.symm_false [BEq α] [PartialEquivBEq α] {a b : α} : (a == b) = false → (b == a) = false :=
-  BEq.comm (α := α) ▸ id
-
-theorem BEq.trans [BEq α] [PartialEquivBEq α] {a b c : α} : a == b → b == c → a == c :=
-  PartialEquivBEq.trans
-
-theorem BEq.neq_of_neq_of_beq [BEq α] [PartialEquivBEq α] {a b c : α} :
-    (a == b) = false → b == c → (a == c) = false :=
-  fun h₁ h₂ => Bool.eq_false_iff.2 fun h₃ => Bool.eq_false_iff.1 h₁ (BEq.trans h₃ (BEq.symm h₂))
-
-theorem BEq.neq_of_beq_of_neq [BEq α] [PartialEquivBEq α] {a b c : α} :
-    a == b → (b == c) = false → (a == c) = false :=
-  fun h₁ h₂ => Bool.eq_false_iff.2 fun h₃ => Bool.eq_false_iff.1 h₂ (BEq.trans (BEq.symm h₁) h₃)
-
-instance (priority := low) [BEq α] [LawfulBEq α] : EquivBEq α where
-  refl := LawfulBEq.rfl
-  symm h := beq_iff_eq.2 <| Eq.symm <| beq_iff_eq.1 h
-  trans hab hbc := beq_iff_eq.2 <| (beq_iff_eq.1 hab).trans <| beq_iff_eq.1 hbc

src/Init/Data/BitVec.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: Kim Morrison
+Authors: Scott Morrison
 -/
 prelude
 import Init.Data.BitVec.Basic

src/Init/Data/BitVec/Basic.lean

@@ -20,8 +20,6 @@ We define many of the bitvector operations from the
 of SMT-LIBv2.
 -/
 
-set_option linter.missingDocs true
-
 /--
 A bitvector of the specified width.
 
@@ -36,14 +34,13 @@ structure BitVec (w : Nat) where
   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)`.
--/
+@[deprecated] protected abbrev Std.BitVec := _root_.BitVec
+
 -- 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
+def BitVec.decEq (a b : BitVec n) : Decidable (a = b) :=
+  match a, b with
   | ⟨n⟩, ⟨m⟩ =>
     if h : n = m then
       isTrue (h ▸ rfl)
@@ -64,19 +61,19 @@ protected def ofNatLt {n : Nat} (i : Nat) (p : i < 2^n) : BitVec n where
 /-- 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
+  toFin := Fin.ofNat' i (Nat.two_pow_pos n)
 
 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
+/-- Given a bitvector `a`, 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
+protected def toNat (a : BitVec n) : Nat := a.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")]
+@[deprecated isLt]
 theorem toNat_lt (x : BitVec n) : x.toNat < 2^n := x.isLt
 
 /-- Theorem for normalizing the bit vector literal representation. -/
@@ -116,76 +113,25 @@ end zero_allOnes
 
 section getXsb
 
-/--
-Return the `i`-th least significant bit.
-
-This will be renamed `getLsb` after the existing deprecated alias is removed.
--/
-@[inline] def getLsb' (x : BitVec w) (i : Fin w) : Bool := x.toNat.testBit i
-
-/-- Return the `i`-th least significant bit or `none` if `i ≥ w`. -/
-@[inline] def getLsb? (x : BitVec w) (i : Nat) : Option Bool :=
-  if h : i < w then some (getLsb' x ⟨i, h⟩) else none
-
-/--
-Return the `i`-th most significant bit.
-
-This will be renamed `getMsb` after the existing deprecated alias is removed.
--/
-@[inline] def getMsb' (x : BitVec w) (i : Fin w) : Bool := x.getLsb' ⟨w-1-i, by omega⟩
-
-/-- Return the `i`-th most significant bit or `none` if `i ≥ w`. -/
-@[inline] def getMsb? (x : BitVec w) (i : Nat) : Option Bool :=
-  if h : i < w then some (getMsb' x ⟨i, h⟩) else none
-
 /-- Return the `i`-th least significant bit or `false` if `i ≥ w`. -/
-@[inline] def getLsbD (x : BitVec w) (i : Nat) : Bool :=
-  x.toNat.testBit i
-
-@[deprecated getLsbD (since := "2024-08-29"), inherit_doc getLsbD]
-def getLsb (x : BitVec w) (i : Nat) : Bool := x.getLsbD i
+@[inline] def getLsb (x : BitVec w) (i : Nat) : Bool := x.toNat.testBit i
 
 /-- Return the `i`-th most significant bit or `false` if `i ≥ w`. -/
-@[inline] def getMsbD (x : BitVec w) (i : Nat) : Bool :=
-  i < w && x.getLsbD (w-1-i)
-
-@[deprecated getMsbD (since := "2024-08-29"), inherit_doc getMsbD]
-def getMsb (x : BitVec w) (i : Nat) : Bool := x.getMsbD i
+@[inline] def getMsb (x : BitVec w) (i : Nat) : Bool := i < w && getLsb x (w-1-i)
 
 /-- Return most-significant bit in bitvector. -/
-@[inline] protected def msb (x : BitVec n) : Bool := getMsbD x 0
+@[inline] protected def msb (a : BitVec n) : Bool := getMsb a 0
 
 end getXsb
 
-section getElem
-
-instance : GetElem (BitVec w) Nat Bool fun _ i => i < w where
-  getElem xs i h := xs.getLsb' ⟨i, h⟩
-
-/-- We prefer `x[i]` as the simp normal form for `getLsb'` -/
-@[simp] theorem getLsb'_eq_getElem (x : BitVec w) (i : Fin w) :
-    x.getLsb' i = x[i] := rfl
-
-/-- We prefer `x[i]?` as the simp normal form for `getLsb?` -/
-@[simp] theorem getLsb?_eq_getElem? (x : BitVec w) (i : Nat) :
-    x.getLsb? i = x[i]? := rfl
-
-theorem getElem_eq_testBit_toNat (x : BitVec w) (i : Nat) (h : i < w) :
-  x[i] = x.toNat.testBit i := rfl
-
-theorem getLsbD_eq_getElem {x : BitVec w} {i : Nat} (h : i < w) :
-    x.getLsbD i = x[i] := rfl
-
-end getElem
-
 section Int
 
 /-- Interpret the bitvector as an integer stored in two's complement form. -/
-protected def toInt (x : BitVec n) : Int :=
-  if 2 * x.toNat < 2^n then
-    x.toNat
+protected def toInt (a : BitVec n) : Int :=
+  if 2 * a.toNat < 2^n then
+    a.toNat
   else
-    (x.toNat : Int) - (2^n : Nat)
+    (a.toNat : Int) - (2^n : Nat)
 
 /-- The `BitVec` with value `(2^n + (i mod 2^n)) mod 2^n`.  -/
 protected def ofInt (n : Nat) (i : Int) : BitVec n := .ofNatLt (i % (Int.ofNat (2^n))).toNat (by
@@ -204,12 +150,12 @@ end Int
 section Syntax
 
 /-- Notation for bit vector literals. `i#n` is a shorthand for `BitVec.ofNat n i`. -/
-syntax:max num noWs "#" noWs term:max : term
-macro_rules | `($i:num#$n) => `(BitVec.ofNat $n $i)
+scoped syntax:max term:max noWs "#" noWs term:max : term
+macro_rules | `($i#$n) => `(BitVec.ofNat $n $i)
 
 /-- Unexpander for bit vector literals. -/
 @[app_unexpander BitVec.ofNat] def unexpandBitVecOfNat : Lean.PrettyPrinter.Unexpander
-  | `($(_) $n $i:num) => `($i:num#$n)
+  | `($(_) $n $i) => `($i#$n)
   | _ => throw ()
 
 /-- Notation for bit vector literals without truncation. `i#'lt` is a shorthand for `BitVec.ofNatLt i lt`. -/
@@ -251,7 +197,7 @@ 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)
+protected def sub (x y : BitVec n) : BitVec n := .ofNat n (x.toNat + (2^n - y.toNat))
 instance : Sub (BitVec n) := ⟨BitVec.sub⟩
 
 /--
@@ -266,7 +212,7 @@ instance : Neg (BitVec n) := ⟨.neg⟩
 /--
 Return the absolute value of a signed bitvector.
 -/
-protected def abs (x : BitVec n) : BitVec n := if x.msb then .neg x else x
+protected def abs (s : BitVec n) : BitVec n := if s.msb then .neg s else s
 
 /--
 Multiplication for bit vectors. This can be interpreted as either signed or unsigned negation
@@ -313,12 +259,12 @@ sdiv 5#4 -2 = -2#4
 sdiv (-7#4) (-2) = 3#4
 ```
 -/
-def sdiv (x y : BitVec n) : BitVec n :=
-  match x.msb, y.msb with
-  | false, false => udiv x y
-  | false, true  => .neg (udiv x (.neg y))
-  | true,  false => .neg (udiv (.neg x) y)
-  | true,  true  => udiv (.neg x) (.neg y)
+def sdiv (s t : BitVec n) : BitVec n :=
+  match s.msb, t.msb with
+  | false, false => udiv s t
+  | false, true  => .neg (udiv s (.neg t))
+  | true,  false => .neg (udiv (.neg s) t)
+  | true,  true  => udiv (.neg s) (.neg t)
 
 /--
 Signed division for bit vectors using SMTLIB rules for division by zero.
@@ -327,40 +273,40 @@ Specifically, `smtSDiv x 0 = if x >= 0 then -1 else 1`
 
 SMT-Lib name: `bvsdiv`.
 -/
-def smtSDiv (x y : BitVec n) : BitVec n :=
-  match x.msb, y.msb with
-  | false, false => smtUDiv x y
-  | false, true  => .neg (smtUDiv x (.neg y))
-  | true,  false => .neg (smtUDiv (.neg x) y)
-  | true,  true  => smtUDiv (.neg x) (.neg y)
+def smtSDiv (s t : BitVec n) : BitVec n :=
+  match s.msb, t.msb with
+  | false, false => smtUDiv s t
+  | false, true  => .neg (smtUDiv s (.neg t))
+  | true,  false => .neg (smtUDiv (.neg s) t)
+  | true,  true  => smtUDiv (.neg s) (.neg t)
 
 /--
 Remainder for signed division rounding to zero.
 
 SMT_Lib name: `bvsrem`.
 -/
-def srem (x y : BitVec n) : BitVec n :=
-  match x.msb, y.msb with
-  | false, false => umod x y
-  | false, true  => umod x (.neg y)
-  | true,  false => .neg (umod (.neg x) y)
-  | true,  true  => .neg (umod (.neg x) (.neg y))
+def srem (s t : BitVec n) : BitVec n :=
+  match s.msb, t.msb with
+  | false, false => umod s t
+  | false, true  => umod s (.neg t)
+  | true,  false => .neg (umod (.neg s) t)
+  | true,  true  => .neg (umod (.neg s) (.neg t))
 
 /--
 Remainder for signed division rounded to negative infinity.
 
 SMT_Lib name: `bvsmod`.
 -/
-def smod (x y : BitVec m) : BitVec m :=
-  match x.msb, y.msb with
-  | false, false => umod x y
+def smod (s t : BitVec m) : BitVec m :=
+  match s.msb, t.msb with
+  | false, false => umod s t
   | false, true =>
-    let u := umod x (.neg y)
-    (if u = .zero m then u else .add u y)
+    let u := umod s (.neg t)
+    (if u = .zero m then u else .add u t)
   | true, false =>
-    let u := umod (.neg x) y
-    (if u = .zero m then u else .sub y u)
-  | true, true => .neg (umod (.neg x) (.neg y))
+    let u := umod (.neg s) t
+    (if u = .zero m then u else .sub t u)
+  | true, true => .neg (umod (.neg s) (.neg t))
 
 end arithmetic
 
@@ -424,8 +370,8 @@ end relations
 
 section cast
 
-/-- `cast eq x` embeds `x` into an equal `BitVec` type. -/
-@[inline] def cast (eq : n = m) (x : BitVec n) : BitVec m := .ofNatLt x.toNat (eq ▸ x.isLt)
+/-- `cast eq i` embeds `i` into an equal `BitVec` type. -/
+@[inline] def cast (eq : n = m) (i : BitVec n) : BitVec m := .ofNatLt i.toNat (eq ▸ i.isLt)
 
 @[simp] theorem cast_ofNat {n m : Nat} (h : n = m) (x : Nat) :
     cast h (BitVec.ofNat n x) = BitVec.ofNat m x := by
@@ -442,7 +388,7 @@ Extraction of bits `start` to `start + len - 1` from a bit vector of size `n` to
 new bitvector of size `len`. If `start + len > n`, then the vector will be zero-padded in the
 high bits.
 -/
-def extractLsb' (start len : Nat) (x : BitVec n) : BitVec len := .ofNat _ (x.toNat >>> start)
+def extractLsb' (start len : Nat) (a : BitVec n) : BitVec len := .ofNat _ (a.toNat >>> start)
 
 /--
 Extraction of bits `hi` (inclusive) down to `lo` (inclusive) from a bit vector of size `n` to
@@ -450,59 +396,44 @@ yield a new bitvector of size `hi - lo + 1`.
 
 SMT-Lib name: `extract`.
 -/
-def extractLsb (hi lo : Nat) (x : BitVec n) : BitVec (hi - lo + 1) := extractLsb' lo _ x
+def extractLsb (hi lo : Nat) (a : BitVec n) : BitVec (hi - lo + 1) := extractLsb' lo _ a
 
 /--
-A version of `setWidth` that requires a proof, but is a noop.
+A version of `zeroExtend` that requires a proof, but is a noop.
 -/
-def setWidth' {n w : Nat} (le : n ≤ w) (x : BitVec n) : BitVec w :=
+def zeroExtend' {n w : Nat} (le : n ≤ w) (x : BitVec n)  : BitVec w :=
   x.toNat#'(by
     apply Nat.lt_of_lt_of_le x.isLt
     exact Nat.pow_le_pow_of_le_right (by trivial) le)
 
-@[deprecated setWidth' (since := "2024-09-18"), inherit_doc setWidth'] abbrev zeroExtend' := @setWidth'
-
 /--
 `shiftLeftZeroExtend x n` returns `zeroExtend (w+n) x <<< n` without
 needing to compute `x % 2^(2+n)`.
 -/
-def shiftLeftZeroExtend (msbs : BitVec w) (m : Nat) : BitVec (w + m) :=
-  let shiftLeftLt {x : Nat} (p : x < 2^w) (m : Nat) : x <<< m < 2^(w + m) := by
+def shiftLeftZeroExtend (msbs : BitVec w) (m : Nat) : BitVec (w+m) :=
+  let shiftLeftLt {x : Nat} (p : x < 2^w) (m : Nat) : x <<< m < 2^(w+m) := by
         simp [Nat.shiftLeft_eq, Nat.pow_add]
         apply Nat.mul_lt_mul_of_pos_right p
         exact (Nat.two_pow_pos m)
   (msbs.toNat <<< m)#'(shiftLeftLt msbs.isLt m)
 
 /--
-Transform `x` of length `w` into a bitvector of length `v`, by either:
-- zero extending, that is, adding zeros in the high bits until it has length `v`, if `v > w`, or
-- truncating the high bits, if `v < w`.
+Zero extend vector `x` of length `w` by adding zeros in the high bits until it has length `v`.
+If `v < w` then it truncates the high bits instead.
 
 SMT-Lib name: `zero_extend`.
 -/
-def setWidth (v : Nat) (x : BitVec w) : BitVec v :=
+def zeroExtend (v : Nat) (x : BitVec w) : BitVec v :=
   if h : w ≤ v then
-    setWidth' h x
+    zeroExtend' h x
   else
     .ofNat v x.toNat
 
 /--
-Transform `x` of length `w` into a bitvector of length `v`, by either:
-- zero extending, that is, adding zeros in the high bits until it has length `v`, if `v > w`, or
-- truncating the high bits, if `v < w`.
-
-SMT-Lib name: `zero_extend`.
+Truncate the high bits of bitvector `x` of length `w`, resulting in a vector of length `v`.
+If `v > w` then it zero-extends the vector instead.
 -/
-abbrev zeroExtend := @setWidth
-
-/--
-Transform `x` of length `w` into a bitvector of length `v`, by either:
-- zero extending, that is, adding zeros in the high bits until it has length `v`, if `v > w`, or
-- truncating the high bits, if `v < w`.
-
-SMT-Lib name: `zero_extend`.
--/
-abbrev truncate := @setWidth
+abbrev truncate := @zeroExtend
 
 /--
 Sign extend a vector of length `w`, extending with `i` additional copies of the most significant
@@ -568,24 +499,24 @@ instance : Complement (BitVec w) := ⟨.not⟩
 
 /--
 Left shift for bit vectors. The low bits are filled with zeros. As a numeric operation, this is
-equivalent to `x * 2^s`, modulo `2^n`.
+equivalent to `a * 2^s`, modulo `2^n`.
 
 SMT-Lib name: `bvshl` except this operator uses a `Nat` shift value.
 -/
-protected def shiftLeft (x : BitVec n) (s : Nat) : BitVec n := BitVec.ofNat n (x.toNat <<< s)
+protected def shiftLeft (a : BitVec n) (s : Nat) : BitVec n := (a.toNat <<< s)#n
 instance : HShiftLeft (BitVec w) Nat (BitVec w) := ⟨.shiftLeft⟩
 
 /--
 (Logical) right shift for bit vectors. The high bits are filled with zeros.
-As a numeric operation, this is equivalent to `x / 2^s`, rounding down.
+As a numeric operation, this is equivalent to `a / 2^s`, rounding down.
 
 SMT-Lib name: `bvlshr` except this operator uses a `Nat` shift value.
 -/
-def ushiftRight (x : BitVec n) (s : Nat) : BitVec n :=
-  (x.toNat >>> s)#'(by
-  let ⟨x, lt⟩ := x
+def ushiftRight (a : BitVec n) (s : Nat) : BitVec n :=
+  (a.toNat >>> s)#'(by
+  let ⟨a, lt⟩ := a
   simp only [BitVec.toNat, Nat.shiftRight_eq_div_pow, Nat.div_lt_iff_lt_mul (Nat.two_pow_pos s)]
-  rw [←Nat.mul_one x]
+  rw [←Nat.mul_one a]
   exact Nat.mul_lt_mul_of_lt_of_le' lt (Nat.two_pow_pos s) (Nat.le_refl 1))
 
 instance : HShiftRight (BitVec w) Nat (BitVec w) := ⟨.ushiftRight⟩
@@ -593,29 +524,15 @@ instance : HShiftRight (BitVec w) Nat (BitVec w) := ⟨.ushiftRight⟩
 /--
 Arithmetic right shift for bit vectors. The high bits are filled with the
 most-significant bit.
-As a numeric operation, this is equivalent to `x.toInt >>> s`.
+As a numeric operation, this is equivalent to `a.toInt >>> s`.
 
 SMT-Lib name: `bvashr` except this operator uses a `Nat` shift value.
 -/
-def sshiftRight (x : BitVec n) (s : Nat) : BitVec n := .ofInt n (x.toInt >>> s)
+def sshiftRight (a : BitVec n) (s : Nat) : BitVec n := .ofInt n (a.toInt >>> s)
 
 instance {n} : HShiftLeft  (BitVec m) (BitVec n) (BitVec m) := ⟨fun x y => x <<< y.toNat⟩
 instance {n} : HShiftRight (BitVec m) (BitVec n) (BitVec m) := ⟨fun x y => x >>> y.toNat⟩
 
-/--
-Arithmetic right shift for bit vectors. The high bits are filled with the
-most-significant bit.
-As a numeric operation, this is equivalent to `a.toInt >>> s.toNat`.
-
-SMT-Lib name: `bvashr`.
--/
-def sshiftRight' (a : BitVec n) (s : BitVec m) : BitVec n := a.sshiftRight s.toNat
-
-/-- Auxiliary function for `rotateLeft`, which does not take into account the case where
-the rotation amount is greater than the bitvector width. -/
-def rotateLeftAux (x : BitVec w) (n : Nat) : BitVec w :=
-  x <<< n ||| x >>> (w - n)
-
 /--
 Rotate left for bit vectors. All the bits of `x` are shifted to higher positions, with the top `n`
 bits wrapping around to fill the low bits.
@@ -625,15 +542,7 @@ rotateLeft  0b0011#4 3 = 0b1001
 ```
 SMT-Lib name: `rotate_left` except this operator uses a `Nat` shift amount.
 -/
-def rotateLeft (x : BitVec w) (n : Nat) : BitVec w := rotateLeftAux x (n % w)
-
-
-/--
-Auxiliary function for `rotateRight`, which does not take into account the case where
-the rotation amount is greater than the bitvector width.
--/
-def rotateRightAux (x : BitVec w) (n : Nat) : BitVec w :=
-  x >>> n ||| x <<< (w - n)
+def rotateLeft (x : BitVec w) (n : Nat) : BitVec w := x <<< n ||| x >>> (w - n)
 
 /--
 Rotate right for bit vectors. All the bits of `x` are shifted to lower positions, with the
@@ -644,7 +553,7 @@ rotateRight 0b01001#5 1 = 0b10100
 ```
 SMT-Lib name: `rotate_right` except this operator uses a `Nat` shift amount.
 -/
-def rotateRight (x : BitVec w) (n : Nat) : BitVec w := rotateRightAux x (n % w)
+def rotateRight (x : BitVec w) (n : Nat) : BitVec w := x >>> n ||| x <<< (w - n)
 
 /--
 Concatenation of bitvectors. This uses the "big endian" convention that the more significant
@@ -653,16 +562,18 @@ input is on the left, so `0xAB#8 ++ 0xCD#8 = 0xABCD#16`.
 SMT-Lib name: `concat`.
 -/
 def append (msbs : BitVec n) (lsbs : BitVec m) : BitVec (n+m) :=
-  shiftLeftZeroExtend msbs m ||| setWidth' (Nat.le_add_left m n) lsbs
+  shiftLeftZeroExtend msbs m ||| zeroExtend' (Nat.le_add_left m n) lsbs
 
 instance : HAppend (BitVec w) (BitVec v) (BitVec (w + v)) := ⟨.append⟩
 
 -- TODO: write this using multiplication
 /-- `replicate i x` concatenates `i` copies of `x` into a new vector of length `w*i`. -/
 def replicate : (i : Nat) → BitVec w → BitVec (w*i)
-  | 0,   _ => 0#0
+  | 0,   _ => 0
   | n+1, x =>
-    (x ++ replicate n x).cast (by rw [Nat.mul_succ]; omega)
+    have hEq : w + w*n = w*(n + 1) := by
+      rw [Nat.mul_add, Nat.add_comm, Nat.mul_one]
+    hEq ▸ (x ++ replicate n x)
 
 /-!
 ### Cons and Concat
@@ -689,13 +600,6 @@ theorem ofBool_append (msb : Bool) (lsbs : BitVec w) :
     ofBool msb ++ lsbs = (cons msb lsbs).cast (Nat.add_comm ..) :=
   rfl
 
-/--
-`twoPow w i` is the bitvector `2^i` if `i < w`, and `0` otherwise.
-That is, 2 to the power `i`.
-For the bitwise point of view, it has the `i`th bit as `1` and all other bits as `0`.
--/
-def twoPow (w : Nat) (i : Nat) : BitVec w := 1#w <<< i
-
 end bitwise
 
 section normalization_eqs