chore: update stage0

.gitattributes

@@ -1,6 +1,3 @@
-*.lean text eol=lf
 *.expected.out -text
 RELEASES.md merge=union
 stage0/** binary linguist-generated
-# The following file is often manually edited, so do show it in diffs
-stage0/src/stdlib_flags.h -binary -linguist-generated

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,30 @@
+### Prerequisites
+
+* [ ] Put an X between the brackets on this line if you have done all of the following:
+    * Checked that your issue isn't already [filed](https://github.com/leanprover/lean4/issues).
+    * Reduced the issue to a self-contained, reproducible test case.
+
+### Description
+
+[Description of the issue]
+
+### Steps to Reproduce
+
+1. [First Step]
+2. [Second Step]
+3. [and so on...]
+
+**Expected behavior:** [What you expect to happen]
+
+**Actual behavior:** [What actually happens]
+
+**Reproduces how often:** [What percentage of the time does it reproduce?]
+
+### Versions
+
+You can get this information from copy and pasting the output of `lean --version`,
+please include the OS and what version of the OS you're running.
+
+### Additional Information
+
+Any additional information, configuration or data that might be necessary to reproduce the issue.

.github/ISSUE_TEMPLATE/bug_report.md

@@ -1,45 +0,0 @@
----
-name: Bug report
-about: Create a bug report
-title: ''
-labels: bug
-assignees: ''
-
----
-
-### Prerequisites
-
-* [ ] 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
-
-[Clear and concise description of the issue]
-
-### Context
-
-[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
-
-1.
-2.
-3.
-
-**Expected behavior:** [Clear and concise description of what you expect to happen]
-
-**Actual behavior:** [Clear and concise description of what actually happens]
-
-### Versions
-
-[Output of `#eval Lean.versionString` or of `lean --version` in the folder that the issue occured in]
-[OS version]
-
-### Additional Information
-
-[Additional information, configuration or data that might be necessary to reproduce the issue]
-
-### Impact
-
-Add :+1: to [issues you consider important](https://github.com/leanprover/lean4/issues?q=is%3Aissue+is%3Aopen+sort%3Areactions-%2B1-desc). If others are impacted by this issue, please ask them to add :+1: to it.

.github/ISSUE_TEMPLATE/rfc.md

@@ -1,26 +0,0 @@
----
-name: Request for comments
-about: Create a feature proposal
-title: 'RFC: '
-labels: RFC
-assignees: ''
-
----
-
-### Proposal
-
-Clear and detailed description of the proposal. Consider the following questions:
-
-  - **User Experience**: How does this feature improve the user experience?
-
-  - **Beneficiaries**: Which Lean users and projects benefit most from this feature/change?
-
-  - **Maintainability**: Will this change streamline code maintenance or simplify its structure?
-
-### Community Feedback
-
-Ideas should be discussed on [the Lean Zulip](https://leanprover.zulipchat.com) prior to submitting a proposal. Summarize all prior discussions and link them here.
-
-### Impact
-
-Add :+1: to [issues you consider important](https://github.com/leanprover/lean4/issues?q=is%3Aissue+is%3Aopen+sort%3Areactions-%2B1-desc). If others benefit from the changes in this proposal being added, please ask them to add :+1: to it.

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,14 +0,0 @@
-# Read this section before submitting
-
-* Ensure your PR follows the [External Contribution Guidelines](https://github.com/leanprover/lean4/blob/master/CONTRIBUTING.md).
-* Please make sure the PR has excellent documentation and tests. If we label it `missing documentation` or `missing tests` then it needs fixing!
-* 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.
-* 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.
-
----
-
-Closes #0000 (`RFC` or `bug` issue number fixed by this PR, if any)

.github/workflows/actionlint.yml

@@ -1,22 +0,0 @@
-name: Actionlint
-on:
-  push:
-    branches:
-      - 'master'
-    paths:
-      - '.github/**'
-  pull_request:
-    paths:
-      - '.github/**'
-  merge_group:
-
-jobs:
-  actionlint:
-    runs-on: ubuntu-latest
-    steps:
-    - name: Checkout
-      uses: actions/checkout@v3
-    - name: actionlint
-      uses: raven-actions/actionlint@v1
-      with:
-        pyflakes: false # we do not use python scripts

.github/workflows/backport.yml

@@ -1,26 +0,0 @@
-name: Backport
-on:
-  pull_request_target:
-    types:
-      - closed
-      - labeled
-
-jobs:
-  backport:
-    name: Backport
-    runs-on: ubuntu-latest
-    # Only react to merged PRs for security reasons.
-    # See https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows#pull_request_target.
-    if: >
-      github.event.pull_request.merged
-      && (
-        github.event.action == 'closed'
-        || (
-          github.event.action == 'labeled'
-          && contains(github.event.label.name, 'backport')
-        )
-      )
-    steps:
-      - uses: tibdex/backport@v2
-        with:
-          github_token: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/ci.yml

@@ -6,252 +6,107 @@ on:
     tags:
       - '*'
   pull_request:
-    types: [opened, synchronize, reopened, labeled]
-  merge_group:
+    branches:
+      - master
   schedule:
     - cron: '0 7 * * *'  # 8AM CET/11PM PT
 
-concurrency:
-  group: ${{ github.workflow }}-${{ github.ref }}-${{ github.event_name }}
-  cancel-in-progress: true
-
 jobs:
-
-  # This job determines various settings for the following CI runs; see the `outputs` for details
-  configure:
+  set-nightly:
+    # don't schedule nightlies on forks
+    if: github.event_name == 'schedule' && github.repository == 'leanprover/lean4'
     runs-on: ubuntu-latest
     outputs:
-      # 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
-      nightly: ${{ steps.set-nightly.outputs.nightly }}
-      # Should this be the CI for a tagged release?
-      # Yes only if a tag is pushed to the `leanprover` repository, and the tag is "v" followed by a valid semver.
-      # It sets `set-release.outputs.RELEASE_TAG` to the tag
-      # and sets `set-release.outputs.{LEAN_VERSION_MAJOR,LEAN_VERSION_MINOR,LEAN_VERSION_PATCH,LEAN_SPECIAL_VERSION_DESC}`
-      # to the semver components parsed via regex.
-      LEAN_VERSION_MAJOR: ${{ steps.set-release.outputs.LEAN_VERSION_MAJOR }}
-      LEAN_VERSION_MINOR: ${{ steps.set-release.outputs.LEAN_VERSION_MINOR }}
-      LEAN_VERSION_PATCH: ${{ steps.set-release.outputs.LEAN_VERSION_PATCH }}
-      LEAN_SPECIAL_VERSION_DESC: ${{ steps.set-release.outputs.LEAN_SPECIAL_VERSION_DESC }}
-      RELEASE_TAG: ${{ steps.set-release.outputs.RELEASE_TAG }}
-
+      nightly: ${{ steps.set.outputs.nightly }}
     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: ${quick}`)
-            let matrix = [
-              {
-                // portable release build: use channel with older glibc (2.27)
-                "name": "Linux LLVM",
-                "os": "ubuntu-latest",
-                "release": false,
-                "quick": false,
-                "shell": "nix-shell --arg pkgsDist \"import (fetchTarball \\\"channel:nixos-19.03\\\") {{}}\" --run \"bash -euxo pipefail {0}\"",
-                "llvm-url": "https://github.com/leanprover/lean-llvm/releases/download/15.0.1/lean-llvm-x86_64-linux-gnu.tar.zst",
-                "prepare-llvm": "../script/prepare-llvm-linux.sh lean-llvm*",
-                "binary-check": "ldd -v",
-                // foreign code may be linked against more recent glibc
-                // reverse-ffi needs to be updated to link to LLVM libraries
-                "CTEST_OPTIONS": "-E 'foreign|leanlaketest_reverse-ffi'",
-                "CMAKE_OPTIONS": "-DLLVM=ON -DLLVM_CONFIG=${GITHUB_WORKSPACE}/build/llvm-host/bin/llvm-config"
-              },
-              {
-                "name": "Linux release",
-                "os": "ubuntu-latest",
-                "release": true,
-                "quick": true,
-                "shell": "nix-shell --arg pkgsDist \"import (fetchTarball \\\"channel:nixos-19.03\\\") {{}}\" --run \"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'"
-              },
-              {
-                "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-latest",
-                "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-latest",
-                "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-shell --arg pkgsDist \"import (fetchTarball \\\"channel:nixos-19.03\\\") {{ localSystem.config = \\\"aarch64-unknown-linux-gnu\\\"; }}\" --run \"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${JSON.stringify(matrix, null, 2)}`)
-            if (quick) {
-              return matrix.filter((job) => job.quick)
-            } else {
-              return matrix
-            }
-
       - name: Checkout
-        uses: actions/checkout@v3
-        # don't schedule nightlies on forks
-        if: github.event_name == 'schedule' && github.repository == 'leanprover/lean4'
+        uses: actions/checkout@v2
       - name: Set Nightly
-        if: github.event_name == 'schedule' && github.repository == 'leanprover/lean4'
-        id: set-nightly
+        id: set
         run: |
           if [[ -n '${{ secrets.PUSH_NIGHTLY_TOKEN }}' ]]; then
             git remote add nightly https://foo:'${{ secrets.PUSH_NIGHTLY_TOKEN }}'@github.com/${{ github.repository_owner }}/lean4-nightly.git
             git fetch nightly --tags
             LEAN_VERSION_STRING="nightly-$(date -u +%F)"
             # do nothing if commit already has a different tag
-            if [[ "$(git name-rev --name-only --tags --no-undefined HEAD 2> /dev/null || echo "$LEAN_VERSION_STRING")" == "$LEAN_VERSION_STRING" ]]; then
-              echo "nightly=$LEAN_VERSION_STRING" >> "$GITHUB_OUTPUT"
+            if [[ $(git name-rev --name-only --tags --no-undefined HEAD 2> /dev/null || echo $LEAN_VERSION_STRING) == $LEAN_VERSION_STRING ]]; then
+              echo "::set-output name=nightly::$LEAN_VERSION_STRING"
             fi
           fi
 
-      - name: Check for official release
-        if: startsWith(github.ref, 'refs/tags/') && github.repository == 'leanprover/lean4'
-        id: set-release
-        run: |
-          TAG_NAME="${GITHUB_REF##*/}"
-
-          # From https://github.com/fsaintjacques/semver-tool/blob/master/src/semver
-
-          NAT='0|[1-9][0-9]*'
-          ALPHANUM='[0-9]*[A-Za-z-][0-9A-Za-z-]*'
-          IDENT="$NAT|$ALPHANUM"
-          FIELD='[0-9A-Za-z-]+'
-
-          SEMVER_REGEX="\
-          ^[vV]?\
-          ($NAT)\\.($NAT)\\.($NAT)\
-          (\\-(${IDENT})(\\.(${IDENT}))*)?\
-          (\\+${FIELD}(\\.${FIELD})*)?$"
-
-          if [[ ${TAG_NAME} =~ ${SEMVER_REGEX} ]]; then
-            echo "Tag ${TAG_NAME} matches SemVer regex, with groups ${BASH_REMATCH[1]} ${BASH_REMATCH[2]} ${BASH_REMATCH[3]} ${BASH_REMATCH[4]}"
-            {
-              echo "LEAN_VERSION_MAJOR=${BASH_REMATCH[1]}"
-              echo "LEAN_VERSION_MINOR=${BASH_REMATCH[2]}"
-              echo "LEAN_VERSION_PATCH=${BASH_REMATCH[3]}"
-              echo "LEAN_SPECIAL_VERSION_DESC=${BASH_REMATCH[4]##-}"
-              echo "RELEASE_TAG=$TAG_NAME"
-            } >> "$GITHUB_OUTPUT"
-          else
-            echo "Tag ${TAG_NAME} did not match SemVer regex."
-          fi
-
   build:
-    needs: [configure]
-    if: github.event_name != 'schedule' || github.repository == 'leanprover/lean4'
-    strategy:
-      matrix:
-        include: ${{fromJson(needs.configure.outputs.matrix)}}
-      # complete all jobs
-      fail-fast: false
+    needs: set-nightly
+    # `always` *must* be used to continue even after a dependency has been skipped
+    if: always() && (github.event_name != 'schedule' || github.repository == 'leanprover/lean4')
     runs-on: ${{ matrix.os }}
     defaults:
       run:
         shell: ${{ matrix.shell || 'nix-shell --run "bash -euxo pipefail {0}"' }}
+    strategy:
+      matrix:
+        include:
+          # portable release build: use channel with older glibc (2.27)
+          - name: Linux release
+            os: ubuntu-latest
+            release: true
+            shell: nix-shell --arg pkgsDist "import (fetchTarball \"channel:nixos-19.03\") {{}}" --run "bash -euxo pipefail {0}"
+            llvm-url: https://github.com/leanprover/lean-llvm/releases/download/14.0.0/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|leanlaketest_git'
+          - name: Linux
+            os: ubuntu-latest
+            check-stage3: true
+            test-speedcenter: true
+          - name: Linux Debug
+            os: ubuntu-latest
+            CMAKE_OPTIONS: -DCMAKE_BUILD_TYPE=Debug
+          - name: Linux fsanitize
+            os: ubuntu-latest
+            # 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 problematic tests
+            CTEST_OPTIONS: -E laketest
+          - name: macOS
+            os: macos-latest
+            release: true
+            shell: bash -euxo pipefail {0}
+            CMAKE_OPTIONS: -DCMAKE_OSX_DEPLOYMENT_TARGET=10.15
+            llvm-url: https://github.com/leanprover/lean-llvm/releases/download/14.0.0/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-latest
+            release: true
+            cross: true
+            shell: bash -euxo pipefail {0}
+            CMAKE_OPTIONS: -DCMAKE_OSX_DEPLOYMENT_TARGET=10.15 -DUSE_GMP=OFF -DLEAN_INSTALL_SUFFIX=-darwin_aarch64
+            llvm-url: https://github.com/leanprover/lean-llvm/releases/download/14.0.0/lean-llvm-aarch64-apple-darwin.tar.zst https://github.com/leanprover/lean-llvm/releases/download/14.0.0/lean-llvm-x86_64-apple-darwin.tar.zst
+            prepare-llvm: EXTRA_FLAGS=--target=aarch64-apple-darwin ../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
+            shell: msys2 {0}
+            CMAKE_OPTIONS: -G "Unix Makefiles"
+            # for reasons unknown, interactivetests are flaky on Windows
+            CTEST_OPTIONS: --repeat until-pass:2
+            llvm-url: https://github.com/leanprover/lean-llvm/releases/download/14.0.0/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: -DCMAKE_PREFIX_PATH=$GMP -DLEAN_INSTALL_SUFFIX=-linux_aarch64
+            release: true
+            cross: true
+            shell: nix-shell --arg pkgsDist "import (fetchTarball \"channel:nixos-19.03\") {{ localSystem.config = \"aarch64-unknown-linux-gnu\"; }}" --run "bash -euxo pipefail {0}"
+            llvm-url: https://github.com/leanprover/lean-llvm/releases/download/14.0.0/lean-llvm-x86_64-linux-gnu.tar.zst https://github.com/leanprover/lean-llvm/releases/download/14.0.0/lean-llvm-aarch64-linux-gnu.tar.zst
+            prepare-llvm: EXTRA_FLAGS=--target=aarch64-unknown-linux-gnu ../script/prepare-llvm-linux.sh lean-llvm-aarch64-* lean-llvm-x86_64-*
+      # complete all jobs
+      fail-fast: false
     name: ${{ matrix.name }}
     env:
       # must be inside workspace
@@ -264,19 +119,14 @@ jobs:
       LSAN_OPTIONS: max_leaks=10
       # somehow MinGW clang64 (or cmake?) defaults to `g++` even though it doesn't exist
       CXX: c++
-      MACOSX_DEPLOYMENT_TARGET: 10.15
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v2
         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: cachix/install-nix-action@v18
-        with:
-          install_url: https://releases.nixos.org/nix/nix-2.12.0/install
-        if: matrix.os == 'ubuntu-latest' && !matrix.cmultilib
+        uses: cachix/install-nix-action@v15
+        if: matrix.os == 'ubuntu-latest'
       - name: Install MSYS2
         uses: msys2/setup-msys2@v2
         with:
@@ -286,21 +136,10 @@ jobs:
         if: matrix.os == 'windows-2022'
       - name: Install Brew Packages
         run: |
-          brew install ccache tree zstd coreutils gmp
+          brew install ccache tree zstd coreutils
         if: matrix.os == 'macos-latest'
-      - name: Setup emsdk
-        uses: mymindstorm/setup-emsdk@v12
-        with:
-          version: 3.1.44
-          actions-cache-folder: emsdk
-        if: matrix.wasm
-      - name: Install 32bit c libs
-        run: |
-          sudo apt-get update
-          sudo apt-get install -y gcc-multilib g++-multilib ccache
-        if: matrix.cmultilib
       - name: Cache
-        uses: actions/cache@v3
+        uses: actions/cache@v2
         with:
           path: .ccache
           key: ${{ matrix.name }}-build-v3-${{ github.sha }}
@@ -312,40 +151,18 @@ jobs:
           # open nix-shell once for initial setup
           true
         if: matrix.os == 'ubuntu-latest'
-      - name: Set up core dumps
-        run: |
-          mkdir -p $PWD/coredumps
-          # store in current directory, for easy uploading together with binary
-          echo $PWD/coredumps/%e.%p.%t | sudo tee /proc/sys/kernel/core_pattern
-        if: matrix.os == 'ubuntu-latest'
       - name: Build
         run: |
           mkdir build
           cd build
-          ulimit -c unlimited # coredumps
-          # arguments passed to `cmake`
-          # this also enables githash embedding into stage 1 library
-          OPTIONS=(-DCHECK_OLEAN_VERSION=ON)
-          OPTIONS+=(-DLEAN_EXTRA_MAKE_OPTS=-DwarningAsError=true)
-          if [[ -n '${{ matrix.cross_target }}' ]]; then
-            # used by `prepare-llvm`
-            export EXTRA_FLAGS=--target=${{ matrix.cross_target }}
-            OPTIONS+=(-DLEAN_PLATFORM_TARGET=${{ matrix.cross_target }})
-          fi
+          OPTIONS=()
           if [[ -n '${{ matrix.prepare-llvm }}' ]]; then
             wget -q ${{ matrix.llvm-url }}
             PREPARE="$(${{ matrix.prepare-llvm }})"
             eval "OPTIONS+=($PREPARE)"
           fi
-          if [[ -n '${{ matrix.release }}' && -n '${{ needs.configure.outputs.nightly }}' ]]; then
-            OPTIONS+=(-DLEAN_SPECIAL_VERSION_DESC=${{ needs.configure.outputs.nightly }})
-          fi
-          if [[ -n '${{ matrix.release }}' && -n '${{ needs.configure.outputs.RELEASE_TAG }}' ]]; then
-            OPTIONS+=(-DLEAN_VERSION_MAJOR=${{ needs.configure.outputs.LEAN_VERSION_MAJOR }})
-            OPTIONS+=(-DLEAN_VERSION_MINOR=${{ needs.configure.outputs.LEAN_VERSION_MINOR }})
-            OPTIONS+=(-DLEAN_VERSION_PATCH=${{ needs.configure.outputs.LEAN_VERSION_PATCH }})
-            OPTIONS+=(-DLEAN_VERSION_IS_RELEASE=1)
-            OPTIONS+=(-DLEAN_SPECIAL_VERSION_DESC=${{ needs.configure.outputs.LEAN_SPECIAL_VERSION_DESC }})
+          if [[ -n '${{ matrix.release }}' && -n '${{ needs.set-nightly.outputs.nightly }}' ]]; then
+            OPTIONS+=(-DLEAN_SPECIAL_VERSION_DESC=${{ needs.set-nightly.outputs.nightly }})
           fi
           # contortion to support empty OPTIONS with old macOS bash
           cmake .. ${{ matrix.CMAKE_OPTIONS }} ${OPTIONS[@]+"${OPTIONS[@]}"} -DLEAN_INSTALL_PREFIX=$PWD/..
@@ -356,19 +173,19 @@ jobs:
       - name: List Install Tree
         run: |
           # omit contents of Init/, ...
-          tree --du -h lean-*-* | grep -E ' (Init|Lean|Lake|LICENSE|[a-z])'
+          tree --du -h lean-* | grep -E ' (Init|Lean|Lake|LICENSE|[a-z])'
       - name: Pack
         run: |
-          dir=$(echo lean-*-*)
+          dir=$(echo lean-*)
           mkdir pack
           # high-compression tar.zst + zip for release, fast tar.zst otherwise
-          if [[ '${{ startsWith(github.ref, 'refs/tags/') && matrix.release }}' == true || -n '${{ needs.configure.outputs.nightly }}' || -n '${{ needs.configure.outputs.RELEASE_TAG }}' ]]; then
+          if [[ '${{ startsWith(github.ref, 'refs/tags/v') && matrix.release }}' == true || -n '${{ needs.set-nightly.outputs.nightly }}' ]]; then
             ${{ matrix.tar || 'tar' }} cf - $dir | zstd -T0 --no-progress -19 -o pack/$dir.tar.zst
             zip -rq pack/$dir.zip $dir
           else
             ${{ matrix.tar || 'tar' }} cf - $dir | zstd -T0 --no-progress -o pack/$dir.tar.zst
           fi
-      - uses: actions/upload-artifact@v3
+      - uses: actions/upload-artifact@v2
         if: matrix.release
         with:
           name: build-${{ matrix.name }}
@@ -380,25 +197,22 @@ jobs:
       - name: Test
         run: |
           cd build/stage1
-          ulimit -c unlimited # coredumps
           # exclude nonreproducible test
-          ctest -j4 --output-on-failure ${{ matrix.CTEST_OPTIONS }} < /dev/null
-        if: (matrix.wasm || !matrix.cross) && needs.configure.outputs.quick == 'false'
+          ctest -j4 --output-on-failure -E leanlaketest_git ${{ matrix.CTEST_OPTIONS }} < /dev/null
+        if: ${{ !matrix.cross }}
       - name: Check Test Binary
         run: ${{ matrix.binary-check }} tests/compiler/534.lean.out
-        if: ${{ !matrix.cross && needs.configure.outputs.quick == 'false' }}
+        if: ${{ !matrix.cross }}
       - name: Build Stage 2
         run: |
           cd build
-          ulimit -c unlimited # coredumps
           make -j4 stage2
-        if: matrix.test-speedcenter
+        if: matrix.build-stage2 || matrix.check-stage3
       - name: Check Stage 3
         run: |
           cd build
-          ulimit -c unlimited # coredumps
           make -j4 check-stage3
-        if: matrix.test-speedcenter
+        if: matrix.check-stage3
       - name: Test Speedcenter Benchmarks
         run: |
           echo -1 | sudo tee /proc/sys/kernel/perf_event_paranoid
@@ -409,57 +223,21 @@ jobs:
       - name: Check rebootstrap
         run: |
           cd build
-          ulimit -c unlimited # coredumps
           make update-stage0 && make -j4
-        if: matrix.name == 'Linux' && needs.configure.outputs.quick == 'false'
+        if: matrix.name == 'Linux'
       - name: CCache stats
         run: ccache -s
-      - name: Show stacktrace for coredumps
-        if: ${{ failure() && matrix.os == 'ubuntu-latest' }}
-        run: |
-          for c in coredumps/*; do
-            progbin="$(file $c | sed "s/.*execfn: '\([^']*\)'.*/\1/")"
-            echo bt | $GDB/bin/gdb -q $progbin $c || true
-          done
-      - name: Upload coredumps
-        uses: actions/upload-artifact@v3
-        if: ${{ failure() && matrix.os == 'ubuntu-latest' }}
-        with:
-          name: coredumps-${{ 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
-  # matrix job separately
-  all-done:
-    name: Build matrix complete
-    runs-on: ubuntu-latest
-    needs: build
-    if: ${{ always() }}
-    steps:
-    - if: contains(needs.*.result, 'failure') ||  contains(needs.*.result, 'cancelled')
-      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:
-  # unofficial releases don't need them, and official release notes will be written by a human.
   release:
-    if: startsWith(github.ref, 'refs/tags/')
+    # When GitHub says "If a job fails, all jobs that need it are skipped unless
+    # the jobs use a conditional expression that causes the job to continue.", don't believe
+    # their lies. It's actually the entire closure (i.e. including `set-nightly`) that
+    # must succeed for subsequent to be run without `always()`.
+    if: always() && needs.build.result == 'success' && startsWith(github.ref, 'refs/tags/v')
     runs-on: ubuntu-latest
     needs: build
     steps:
-      - uses: actions/download-artifact@v3
+      - uses: actions/download-artifact@v2
         with:
           path: artifacts
       - name: Release
@@ -470,36 +248,33 @@ jobs:
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
 
-  # This job creates nightly releases during the cron job.
-  # It is responsible for creating the tag, and automatically generating a changelog.
   release-nightly:
-    needs: [configure, build]
-    if: needs.configure.outputs.nightly
+    needs: [set-nightly, build]
+    if: needs.set-nightly.outputs.nightly
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v2
         with:
           # needed for tagging
           fetch-depth: 0
           token: ${{ secrets.PUSH_NIGHTLY_TOKEN }}
-      - uses: actions/download-artifact@v3
+      - uses: actions/download-artifact@v2
         with:
           path: artifacts
       - name: Prepare Nightly Release
         run: |
           git remote add nightly https://foo:'${{ secrets.PUSH_NIGHTLY_TOKEN }}'@github.com/${{ github.repository_owner }}/lean4-nightly.git
           git fetch nightly --tags
-          git tag "${{ needs.configure.outputs.nightly }}"
-          git push nightly "${{ needs.configure.outputs.nightly }}"
-          git push -f origin refs/tags/${{ needs.configure.outputs.nightly }}:refs/heads/nightly
-          last_tag="$(git log HEAD^ --simplify-by-decoration --pretty="format:%d" | grep -o "nightly-[-0-9]*" | head -n 1)"
+          git tag ${{ needs.set-nightly.outputs.nightly }}
+          git push nightly ${{ needs.set-nightly.outputs.nightly }}
+          last_tag=$(git describe HEAD^ --abbrev=0 --tags)
           echo -e "*Changes since ${last_tag}:*\n\n" > diff.md
-          git show "$last_tag":RELEASES.md > old.md
+          git show $last_tag:RELEASES.md > old.md
           #./script/diff_changelogs.py old.md doc/changes.md >> diff.md
           diff --changed-group-format='%>' --unchanged-group-format='' old.md RELEASES.md >> diff.md || true
           echo -e "\n*Full commit log*\n" >> diff.md
-          git log --oneline "$last_tag"..HEAD | sed 's/^/* /' >> diff.md
+          git log --oneline $last_tag..HEAD | sed 's/^/* /' >> diff.md
       - name: Release Nightly
         uses: softprops/action-gh-release@v1
         with:
@@ -507,7 +282,7 @@ jobs:
           prerelease: true
           files: artifacts/*/*
           fail_on_unmatched_files: true
-          tag_name: ${{ needs.configure.outputs.nightly }}
+          tag_name: ${{ needs.set-nightly.outputs.nightly }}
           repository: ${{ github.repository_owner }}/lean4-nightly
         env:
           GITHUB_TOKEN: ${{ secrets.PUSH_NIGHTLY_TOKEN }}

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

@@ -1,43 +0,0 @@
-# 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
-
-on:
-  issue_comment:
-    types: [created]
-
-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'))
-    runs-on: ubuntu-latest
-
-    steps:
-    - name: Add label based on comment
-      uses: actions/github-script@v7
-      with:
-        github-token: ${{ secrets.GITHUB_TOKEN }}
-        script: |
-          const { owner, repo, number: issue_number  } = context.issue;
-          const commentLines = context.payload.comment.body.split('\r\n');
-
-          const awaitingReview = commentLines.includes('awaiting-review');
-          const awaitingAuthor = commentLines.includes('awaiting-author');
-          const wip = commentLines.includes('WIP');
-
-          if (awaitingReview || awaitingAuthor || wip) {
-            await github.rest.issues.removeLabel({ owner, repo, issue_number, name: 'awaiting-review' }).catch(() => {});
-            await github.rest.issues.removeLabel({ owner, repo, issue_number, name: 'awaiting-author' }).catch(() => {});
-            await github.rest.issues.removeLabel({ owner, repo, issue_number, name: 'WIP' }).catch(() => {});
-          }
-
-          if (awaitingReview) {
-            await github.rest.issues.addLabels({ owner, repo, issue_number, labels: ['awaiting-review'] });
-          }
-          if (awaitingAuthor) {
-            await github.rest.issues.addLabels({ owner, repo, issue_number, labels: ['awaiting-author'] });
-          }
-          if (wip) {
-            await github.rest.issues.addLabels({ owner, repo, issue_number, labels: ['WIP'] });
-          }

.github/workflows/nix-ci.yml

@@ -6,18 +6,15 @@ on:
     tags:
       - '*'
   pull_request:
-  merge_group:
-
-concurrency:
-  group: ${{ github.workflow }}-${{ github.ref }}
-  cancel-in-progress: true
+    branches:
+      - master
 
 jobs:
   Build:
     runs-on: ${{ matrix.os }}
     defaults:
       run:
-        shell: nix run .#ciShell -- bash -euxo pipefail {0}
+        shell: nix -v --experimental-features "nix-command flakes" run .#ciShell -- bash -euxo pipefail {0}
     strategy:
       matrix:
         include:
@@ -29,15 +26,20 @@ jobs:
       fail-fast: false
     name: ${{ matrix.name }}
     env:
-      NIX_BUILD_ARGS: --print-build-logs --fallback
+      NIX_BUILD_ARGS: -v --print-build-logs --fallback
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v2
+      - name: Install Nix
+        uses: cachix/install-nix-action@v15
         with:
-          # the default is to use a virtual merge commit between the PR and master: just use the PR
-          ref: ${{ github.event.pull_request.head.sha }}
+          # https://github.com/NixOS/nix/issues/6572
+          install_url: https://releases.nixos.org/nix/nix-2.7.0/install
+          extra_nix_config: |
+            extra-sandbox-paths = /nix/var/cache/ccache
+            substituters = file://${{ github.workspace }}/nix-store-cache-copy?priority=10&trusted=true https://cache.nixos.org
       - name: Set Up Nix Cache
-        uses: actions/cache@v3
+        uses: actions/cache@v2
         with:
           path: nix-store-cache
           key: ${{ matrix.name }}-nix-store-cache-${{ github.sha }}
@@ -49,18 +51,13 @@ jobs:
         run: |
           # Nix seems to mutate the cache, so make a copy
           cp -r nix-store-cache nix-store-cache-copy || true
-      - name: Install Nix
-        uses: DeterminateSystems/nix-installer-action@main
-        with:
-          extra-conf: |
-            extra-sandbox-paths = /nix/var/cache/ccache?
-            substituters = file://${{ github.workspace }}/nix-store-cache-copy?priority=10&trusted=true https://cache.nixos.org  
       - name: Prepare CCache Cache
+        shell: bash -euxo pipefail {0}
         run: |
           sudo mkdir -m0770 -p /nix/var/cache/ccache
           sudo chown -R $USER /nix/var/cache/ccache
       - name: Setup CCache Cache
-        uses: actions/cache@v3
+        uses: actions/cache@v2
         with:
           path: /nix/var/cache/ccache
           key: ${{ matrix.name }}-nix-ccache-${{ github.sha }}
@@ -68,36 +65,28 @@ jobs:
           restore-keys: |
             ${{ matrix.name }}-nix-ccache
       - name: Further Set Up CCache Cache
+        shell: bash -euxo pipefail {0}
         run: |
           sudo chown -R root:nixbld /nix/var/cache
           sudo chmod -R 770 /nix/var/cache
       - name: Install Cachix
-        uses: cachix/cachix-action@v12
+        uses: cachix/cachix-action@v10
         with:
           name: lean4
           authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
           skipPush: true  # we push specific outputs only
       - name: Build
         run: |
-          nix build $NIX_BUILD_ARGS .#cacheRoots -o push-build
+          # .o files are not a runtime dependency on macOS because of lack of thin archives
+          nix build $NIX_BUILD_ARGS .#stage0 .#stage1.lean-all .#Lean.oTree .#iTree .#modDepsFiles -o push-build
       - name: Test
         run: |
           nix build $NIX_BUILD_ARGS .#test -o push-test
       - name: Build manual
         run: |
-          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#{lean-mdbook,leanInk,alectryon,test} -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
         if: matrix.name == 'Nix Linux'
-      - name: Check manual for broken links
-        id: lychee
-        uses: lycheeverse/lychee-action@v1.9.0
-        with:
-          fail: false  # report errors but do not block CI on temporary failures
-          # gmplib.org consistently times out from GH actions
-          # the GitHub token is to avoid rate limiting
-          args: --base './dist' --no-progress --github-token ${{ secrets.GITHUB_TOKEN }} --exclude 'gmplib.org' './dist/**/*.html'
       - name: Push to Cachix
         run: |
           [ -z "${{ secrets.CACHIX_AUTH_TOKEN }}" ] || cachix push -j4 lean4 ./push-* || true
@@ -105,29 +94,13 @@ jobs:
         run: |
           rm -rf nix-store-cache || true
           nix copy ./push-* --to file://$PWD/nix-store-cache?compression=none
-      - id: deploy-info
-        name: Compute Deployment Metadata
-        run: |
-          set -e
-          python3 -c 'import base64; print("alias="+base64.urlsafe_b64encode(bytes.fromhex("${{github.sha}}")).decode("utf-8").rstrip("="))' >> "$GITHUB_OUTPUT"
-          echo "message=`git log -1 --pretty=format:"%s"`" >> "$GITHUB_OUTPUT"
-      - name: Publish manual to Netlify
-        uses: nwtgck/actions-netlify@v2.0
-        id: publish-manual
+      - name: Publish manual
+        uses: peaceiris/actions-gh-pages@v3
         with:
-          publish-dir: ./dist
-          production-branch: master
-          github-token: ${{ secrets.GITHUB_TOKEN }}
-          deploy-message: |
-            ${{ github.event_name == 'pull_request' && format('pr#{0}: {1}', github.event.number, github.event.pull_request.title) || format('ref/{0}: {1}', github.ref_name, steps.deploy-info.outputs.message) }}
-          alias: ${{ steps.deploy-info.outputs.alias }}
-          enable-commit-comment: false
-          enable-pull-request-comment: false
-          github-deployment-environment: "lean-lang.org/lean4/doc"
-          fails-without-credentials: false
-        env:
-          NETLIFY_AUTH_TOKEN: ${{ secrets.NETLIFY_AUTH_TOKEN }}
-          NETLIFY_SITE_ID: "b8e805d2-7e9b-4f80-91fb-a84d72fc4a68"
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          publish_dir: ./result
+          destination_dir: ./doc
+        if: matrix.name == 'Nix Linux' && github.ref == 'refs/heads/master' && github.event_name == 'push'
       - name: Fixup CCache Cache
         run: |
           sudo chown -R $USER /nix/var/cache

.github/workflows/pr-release.yml

@@ -1,339 +0,0 @@
-# Push a release to the lean4-pr-releases repository, whenever someone pushes to a PR branch.
-
-# This needs to run with the `secrets.PR_RELEASES_TOKEN` token available,
-# but PR branches will generally come from forks,
-# so it is not possible to run this using the `pull_request` or `pull_request_target` workflows.
-# Instead we use `workflow_run`, which essentially allows us to escalate privileges
-# (but only runs the CI as described in the `master` branch, not in the PR branch).
-
-# The main specification/documentation for this workflow is at
-# https://leanprover-community.github.io/contribute/tags_and_branches.html
-# Keep that in sync!
-
-name: PR release
-
-on:
-  workflow_run: # https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows#workflow_run
-    workflows: [CI]
-    types: [completed]
-
-jobs:
-  on-success:
-    runs-on: ubuntu-latest
-    if: github.event.workflow_run.conclusion == 'success' && github.event.workflow_run.event == 'pull_request' && github.repository == 'leanprover/lean4'
-    steps:
-      - name: Retrieve information about the original workflow
-        uses: potiuk/get-workflow-origin@v1_1 # https://github.com/marketplace/actions/get-workflow-origin
-        # This action is deprecated and archived, but it seems hard to find a better solution for getting the PR number
-        # see https://github.com/orgs/community/discussions/25220 for some discussion
-        id: workflow-info
-        with:
-          token: ${{ secrets.GITHUB_TOKEN }}
-          sourceRunId: ${{ github.event.workflow_run.id }}
-
-      - name: Download artifact from the previous workflow.
-        if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' }}
-        id: download-artifact
-        uses: dawidd6/action-download-artifact@v2 # https://github.com/marketplace/actions/download-workflow-artifact
-        with:
-          run_id: ${{ github.event.workflow_run.id }}
-          path: artifacts
-          name: build-.*
-          name_is_regexp: true
-
-      - name: Push tag
-        if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' }}
-        run: |
-          git init --bare lean4.git
-          git -C lean4.git remote add origin https://github.com/${{ github.repository_owner }}/lean4.git
-          git -C lean4.git fetch -n origin master
-          git -C lean4.git fetch -n origin "${{ steps.workflow-info.outputs.sourceHeadSha }}"
-          git -C lean4.git tag -f pr-release-${{ steps.workflow-info.outputs.pullRequestNumber }} "${{ steps.workflow-info.outputs.sourceHeadSha }}"
-          git -C lean4.git remote add pr-releases https://foo:'${{ secrets.PR_RELEASES_TOKEN }}'@github.com/${{ github.repository_owner }}/lean4-pr-releases.git
-          git -C lean4.git push -f pr-releases pr-release-${{ steps.workflow-info.outputs.pullRequestNumber }}
-      - name: Delete existing release if present
-        if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' }}
-        run: |
-          # Try to delete any existing release for the current PR.
-          gh release delete --repo ${{ github.repository_owner }}/lean4-pr-releases pr-release-${{ steps.workflow-info.outputs.pullRequestNumber }} -y || true
-        env:
-          GH_TOKEN: ${{ secrets.PR_RELEASES_TOKEN }}
-      - name: Release
-        if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' }}
-        uses: softprops/action-gh-release@v1
-        with:
-          name: Release for PR ${{ steps.workflow-info.outputs.pullRequestNumber }}
-          # There are coredumps files here as well, but all in deeper subdirectories.
-          files: artifacts/*/*
-          fail_on_unmatched_files: true
-          draft: false
-          tag_name: pr-release-${{ steps.workflow-info.outputs.pullRequestNumber }}
-          repository: ${{ github.repository_owner }}/lean4-pr-releases
-        env:
-          # The token used here must have `workflow` privileges.
-          GITHUB_TOKEN: ${{ secrets.PR_RELEASES_TOKEN }}
-
-      - name: Report release status
-        if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' }}
-        uses: actions/github-script@v6
-        with:
-          script: |
-            await github.rest.repos.createCommitStatus({
-              owner: context.repo.owner,
-              repo: context.repo.repo,
-              sha: "${{ steps.workflow-info.outputs.sourceHeadSha }}",
-              state: "success",
-              context: "PR toolchain",
-              description: "${{ github.repository_owner }}/lean4-pr-releases:pr-release-${{ steps.workflow-info.outputs.pullRequestNumber }}",
-            });
-
-      - name: Add label
-        if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' }}
-        uses: actions/github-script@v7
-        with:
-          script: |
-            await github.rest.issues.addLabels({
-              issue_number: ${{ steps.workflow-info.outputs.pullRequestNumber }},
-              owner: context.repo.owner,
-              repo: context.repo.repo,
-              labels: ['toolchain-available']
-            })
-
-      # Next, determine the most recent nightly release in this PR's history.
-      - name: Find most recent nightly in feature branch
-        id: most-recent-nightly-tag
-        if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' }}
-        run: |
-          git -C lean4.git remote add nightly https://github.com/leanprover/lean4-nightly.git
-          git -C lean4.git fetch nightly '+refs/tags/nightly-*:refs/tags/nightly-*'
-          git -C lean4.git tag --merged "${{ steps.workflow-info.outputs.sourceHeadSha }}" --list "nightly-*" \
-            | sort -rV | head -n 1 | sed "s/^nightly-*/MOST_RECENT_NIGHTLY=/" | tee -a "$GITHUB_ENV"
-
-      - name: 'Setup jq'
-        if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' }}
-        uses: dcarbone/install-jq-action@v1.0.1
-
-      # Check that the most recently nightly coincides with 'git merge-base HEAD master'
-      - name: Check merge-base and nightly-testing-YYYY-MM-DD
-        if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' }}
-        id: ready
-        run: |
-          echo "Most recent nightly release in your branch: $MOST_RECENT_NIGHTLY"
-          NIGHTLY_SHA=$(git -C lean4.git rev-parse "nightly-$MOST_RECENT_NIGHTLY^{commit}")
-          echo "SHA of most recent nightly release: $NIGHTLY_SHA"
-          MERGE_BASE_SHA=$(git -C lean4.git merge-base origin/master "${{ steps.workflow-info.outputs.sourceHeadSha }}")
-          echo "SHA of merge-base: $MERGE_BASE_SHA"
-          if [ "$NIGHTLY_SHA" = "$MERGE_BASE_SHA" ]; then
-            echo "The merge base of this PR coincides with the nightly release"
-
-            MATHLIB_REMOTE_TAGS="$(git ls-remote https://github.com/leanprover-community/mathlib4.git nightly-testing-"$MOST_RECENT_NIGHTLY")"
-
-            if [[ -n "$MATHLIB_REMOTE_TAGS" ]]; then
-              echo "... and Mathlib has a 'nightly-testing-$MOST_RECENT_NIGHTLY' tag."
-              MESSAGE=""
-            else
-              echo "... but Mathlib does not yet have a 'nightly-testing-$MOST_RECENT_NIGHTLY' tag."
-              MESSAGE="- ❗ Mathlib CI can not be attempted yet, as the \`nightly-testing-$MOST_RECENT_NIGHTLY\` tag does not exist there yet. We will retry when you push more commits. If you rebase your branch onto \`nightly-with-mathlib\`, Mathlib CI should run now."
-            fi
-
-            STD_REMOTE_TAGS="$(git ls-remote https://github.com/leanprover/std4.git nightly-testing-"$MOST_RECENT_NIGHTLY")"
-
-            if [[ -n "$STD_REMOTE_TAGS" ]]; then
-              echo "... and Std has a 'nightly-testing-$MOST_RECENT_NIGHTLY' tag."
-              MESSAGE=""
-            else
-              echo "... but Std does not yet have a 'nightly-testing-$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
-            echo "The most recently nightly tag on this branch has SHA: $NIGHTLY_SHA"
-            echo "but 'git merge-base origin/master HEAD' reported: $MERGE_BASE_SHA"
-            git -C lean4.git log -10 origin/master
-
-            MESSAGE="- ❗ Std/Mathlib CI will not be attempted unless your PR branches off the \`nightly-with-mathlib\` branch."
-          fi
-
-          if [[ -n "$MESSAGE" ]]; then
-
-            echo "Checking existing messages"
-
-            # The code for updating comments is duplicated in mathlib's
-            # scripts/lean-pr-testing-comments.sh
-            # so keep in sync
-
-            # Use GitHub API to check if a comment already exists
-            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"))')"
-            existing_comment_id="$(echo "$existing_comment" | jq -r .id)"
-            existing_comment_body="$(echo "$existing_comment" | jq -r .body)"
-
-            if [[ "$existing_comment_body" != *"$MESSAGE"* ]]; then
-              MESSAGE="$MESSAGE ($(date "+%Y-%m-%d %H:%M:%S"))"
-
-              echo "Posting message to the comments: $MESSAGE"
-
-              # Append new result to the existing comment or post a new comment
-              # It's essential we use the MATHLIB4_BOT token here, so that Mathlib CI can subsequently edit the comment.
-              if [ -z "$existing_comment_id" ]; then
-                INTRO="Mathlib CI status ([docs](https://leanprover-community.github.io/contribute/tags_and_branches.html)):"
-                # Post new comment with a bullet point
-                echo "Posting as new comment at leanprover/lean4/issues/${{ steps.workflow-info.outputs.pullRequestNumber }}/comments"
-                curl -L -s \
-                  -X POST \
-                  -H "Authorization: token ${{ secrets.MATHLIB4_BOT }}" \
-                  -H "Accept: application/vnd.github.v3+json" \
-                  -d "$(jq --null-input --arg intro "$INTRO" --arg val "$MESSAGE" '{"body":($intro + "\n" + $val)}')" \
-                  "https://api.github.com/repos/leanprover/lean4/issues/${{ steps.workflow-info.outputs.pullRequestNumber }}/comments"
-              else
-                # Append new result to the existing comment
-                echo "Appending to existing comment at leanprover/lean4/issues/${{ steps.workflow-info.outputs.pullRequestNumber }}/comments"
-                curl -L -s \
-                  -X PATCH \
-                  -H "Authorization: token ${{ secrets.MATHLIB4_BOT }}" \
-                  -H "Accept: application/vnd.github.v3+json" \
-                  -d "$(jq --null-input --arg existing "$existing_comment_body" --arg message "$MESSAGE" '{"body":($existing + "\n" + $message)}')" \
-                  "https://api.github.com/repos/leanprover/lean4/issues/comments/$existing_comment_id"
-              fi
-            else
-              echo "The message already exists in the comment body."
-            fi
-            echo "mathlib_ready=false" >> "$GITHUB_OUTPUT"
-          else
-            echo "mathlib_ready=true" >> "$GITHUB_OUTPUT"
-          fi
-
-      - name: Report mathlib base
-        if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' && steps.ready.outputs.mathlib_ready == 'true' }}
-        uses: actions/github-script@v6
-        with:
-          script: |
-            const description =
-              process.env.MOST_RECENT_NIGHTLY ?
-              "nightly-" + process.env.MOST_RECENT_NIGHTLY :
-              "not branched off nightly";
-            await github.rest.repos.createCommitStatus({
-              owner: context.repo.owner,
-              repo: context.repo.repo,
-              sha: "${{ steps.workflow-info.outputs.sourceHeadSha }}",
-              state: "success",
-              context: "PR branched off:",
-              description: description,
-            });
-
-      # 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 Std repository with all branches
-      - name: Checkout Std repository
-        if: steps.workflow-info.outputs.pullRequestNumber != '' && steps.ready.outputs.mathlib_ready == 'true'
-        uses: actions/checkout@v3
-        with:
-          repository: leanprover/std4
-          token: ${{ secrets.MATHLIB4_BOT }}
-          ref: nightly-testing
-          fetch-depth: 0 # This ensures we check out all tags and branches.
-
-      - name: Check if tag exists
-        if: steps.workflow-info.outputs.pullRequestNumber != '' && steps.ready.outputs.mathlib_ready == 'true'
-        id: check_std_tag
-        run: |
-          git config user.name "leanprover-community-mathlib4-bot"
-          git config user.email "leanprover-community-mathlib4-bot@users.noreply.github.com"
-
-          if git ls-remote --heads --tags --exit-code origin "nightly-testing-${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 Std. Falling back to 'nightly-testing'."
-            BASE=nightly-testing
-          fi
-
-          echo "Using base branch: $BASE"
-
-          EXISTS="$(git ls-remote --heads origin lean-pr-testing-${{ steps.workflow-info.outputs.pullRequestNumber }} | wc -l)"
-          echo "Branch exists: $EXISTS"
-          if [ "$EXISTS" = "0" ]; then
-            echo "Branch does not exist, creating it."
-            git switch -c lean-pr-testing-${{ steps.workflow-info.outputs.pullRequestNumber }} "$BASE"
-            echo "leanprover/lean4-pr-releases:pr-release-${{ steps.workflow-info.outputs.pullRequestNumber }}" > lean-toolchain
-            git add lean-toolchain
-            git commit -m "Update lean-toolchain for testing https://github.com/leanprover/lean4/pull/${{ steps.workflow-info.outputs.pullRequestNumber }}"
-          else
-            echo "Branch already exists, pushing an empty commit."
-            git switch lean-pr-testing-${{ steps.workflow-info.outputs.pullRequestNumber }}
-            # The Std `nightly-testing` or `nightly-testing-YYYY-MM-DD` branch may have moved since this branch was created, so merge their changes.
-            # (This should no longer be possible once `nightly-testing-YYYY-MM-DD` is a tag, but it is still safe to merge.)
-            git merge "$BASE" --strategy-option ours --no-commit --allow-unrelated-histories
-            git commit --allow-empty -m "Trigger CI for https://github.com/leanprover/lean4/pull/${{ steps.workflow-info.outputs.pullRequestNumber }}"
-          fi
-
-      - name: Push changes
-        if: steps.workflow-info.outputs.pullRequestNumber != '' && steps.ready.outputs.mathlib_ready == 'true'
-        run: |
-          git push origin lean-pr-testing-${{ steps.workflow-info.outputs.pullRequestNumber }}
-
-
-      # We next automatically create a Mathlib branch using this toolchain.
-      # Mathlib CI will be responsible for reporting back success or failure
-      # to the PR comments asynchronously.
-      - name: Cleanup workspace
-        if: steps.workflow-info.outputs.pullRequestNumber != '' && steps.ready.outputs.mathlib_ready == 'true'
-        run: |
-          sudo rm -rf ./*
-
-      # 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@v3
-        with:
-          repository: leanprover-community/mathlib4
-          token: ${{ secrets.MATHLIB4_BOT }}
-          ref: nightly-testing
-          fetch-depth: 0 # This ensures we check out all tags and branches.
-
-      - name: Check if tag exists
-        if: steps.workflow-info.outputs.pullRequestNumber != '' && steps.ready.outputs.mathlib_ready == 'true'
-        id: check_mathlib_tag
-        run: |
-          git config user.name "leanprover-community-mathlib4-bot"
-          git config user.email "leanprover-community-mathlib4-bot@users.noreply.github.com"
-
-          if git ls-remote --heads --tags --exit-code origin "nightly-testing-${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}' branch at Mathlib. Falling back to 'nightly-testing'."
-            BASE=nightly-testing
-          fi
-
-          echo "Using base tag: $BASE"
-
-          EXISTS="$(git ls-remote --heads origin lean-pr-testing-${{ steps.workflow-info.outputs.pullRequestNumber }} | wc -l)"
-          echo "Branch exists: $EXISTS"
-          if [ "$EXISTS" = "0" ]; then
-            echo "Branch does not exist, creating it."
-            git switch -c lean-pr-testing-${{ steps.workflow-info.outputs.pullRequestNumber }} "$BASE"
-            echo "leanprover/lean4-pr-releases:pr-release-${{ steps.workflow-info.outputs.pullRequestNumber }}" > lean-toolchain
-            git add lean-toolchain
-            sed -i "s/require std from git \"https:\/\/github.com\/leanprover\/std4\" @ \".\+\"/require std from git \"https:\/\/github.com\/leanprover\/std4\" @ \"nightly-testing-${MOST_RECENT_NIGHTLY}\"/" lakefile.lean
-            git add lakefile.lean
-            git commit -m "Update lean-toolchain for testing https://github.com/leanprover/lean4/pull/${{ steps.workflow-info.outputs.pullRequestNumber }}"
-          else
-            echo "Branch already exists, pushing an empty commit."
-            git switch lean-pr-testing-${{ 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 "$BASE" --strategy-option ours --no-commit --allow-unrelated-histories
-            git commit --allow-empty -m "Trigger CI for https://github.com/leanprover/lean4/pull/${{ steps.workflow-info.outputs.pullRequestNumber }}"
-          fi
-
-      - name: Push changes
-        if: steps.workflow-info.outputs.pullRequestNumber != '' && steps.ready.outputs.mathlib_ready == 'true'
-        run: |
-          git push origin lean-pr-testing-${{ steps.workflow-info.outputs.pullRequestNumber }}

.github/workflows/pr-title.yml

@@ -1,20 +0,0 @@
-name: Check PR title for commit convention
-
-on:
-  merge_group:
-  pull_request:
-    types: [opened, synchronize, reopened, edited]
-
-jobs:
-  check-pr-title:
-    runs-on: ubuntu-latest
-    steps:
-      - name: Check PR title
-        uses: actions/github-script@v7
-        with:
-          script: |
-            const msg = context.payload.pull_request? context.payload.pull_request.title : context.payload.merge_group.head_commit.message;
-            console.log(`Message: ${msg}`)
-            if (!/^(feat|fix|doc|style|refactor|test|chore|perf): .*[^.]($|\n\n)/.test(msg)) {
-              core.setFailed('PR title does not follow the Commit Convention (https://leanprover.github.io/lean4/doc/dev/commit_convention.html).');
-            }

.github/workflows/pr.yml

@@ -0,0 +1,31 @@
+name: sanity-check opened PRs
+
+on:
+  # needs read/write GH token, do *not* execute arbitrary code from PR
+  pull_request_target:
+    types: [opened]
+
+jobs:
+  check-pr:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check Commit Message
+        uses: actions/github-script@v3
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          script: |
+            const { data: commits } = await github.pulls.listCommits({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              pull_number: context.issue.number,
+            });
+            console.log(commits[0].commit.message);
+            // check first commit only (and only once) since later commits might be intended to be squashed away
+            if (!/^(feat|fix|doc|style|refactor|test|chore|perf): .*[^.]($|\n\n)/.test(commits[0].commit.message)) {
+              await github.issues.createComment({
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                issue_number: context.issue.number,
+                body: 'Thanks for your contribution! Please make sure to follow our [Commit Convention](https://leanprover.github.io/lean4/doc/dev/commit_convention.html).',
+              });
+            }

.github/workflows/stale.yml

@@ -1,20 +0,0 @@
-name: 'Label stale PRs'
-on:
-  schedule:
-    - cron: '30 1 * * *'
-  workflow_dispatch:
-
-permissions:
-  pull-requests: write
-
-jobs:
-  stale:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/stale@v8
-        with:
-          days-before-stale: -1
-          days-before-pr-stale: 30
-          days-before-close: -1
-          stale-pr-label: 'stale'
-          only-labels: 'awaiting-author'

.github/workflows/update-stage0.yml

@@ -1,64 +0,0 @@
-name: Update stage0
-
-# This action will update stage0 on master as soon as
-# src/stdlib_flags.h and stage0/src/stdlib_flags.h
-# are out of sync there, or when manually triggered.
-# The update bypasses the merge queue to be quick.
-# Also see <doc/dev/bootstrap.md>.
-
-on:
-  push:
-    branches:
-      - 'master'
-  workflow_dispatch:
-
-concurrency:
-  group: stage0
-  cancel-in-progress: true
-
-jobs:
-  update-stage0:
-    runs-on: ubuntu-latest
-    steps:
-    # 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@v3
-      with:
-        ssh-key: ${{secrets.STAGE0_SSH_KEY}}
-    - run: echo "should_update_stage0=yes" >> "$GITHUB_ENV"
-    - name: Check if automatic update is needed
-      if: github.event_name == 'push'
-      run: |
-        if diff -u src/stdlib_flags.h stage0/src/stdlib_flags.h
-        then
-          echo "src/stdlib_flags.h and stage0/src/stdlib_flags.h agree, nothing to do"
-          echo "should_update_stage0=no" >> "$GITHUB_ENV"
-        fi
-    - name: Setup git user
-      if: env.should_update_stage0 == 'yes'
-      run: |
-          git config --global user.name "Lean stage0 autoupdater"
-          git config --global user.email "<>"
-    - if: env.should_update_stage0 == 'yes'
-      uses: DeterminateSystems/nix-installer-action@main
-    # Would be nice, but does not work yet:
-    # https://github.com/DeterminateSystems/magic-nix-cache/issues/39
-    # This action does not run that often and building runs in a few minutes, so ok for now
-    #- if: env.should_update_stage0 == 'yes'
-    #  uses: DeterminateSystems/magic-nix-cache-action@v2
-    - if: env.should_update_stage0 == 'yes'
-      name: Install Cachix
-      uses: cachix/cachix-action@v12
-      with:
-        name: lean4
-    - if: env.should_update_stage0 == 'yes'
-      run: nix run .#update-stage0-commit
-    - if: env.should_update_stage0 == 'yes'
-      run: git show --stat
-    - if: env.should_update_stage0 == 'yes' && github.event_name == 'push'
-      name: Sanity check # to avoid loops
-      run: |
-        diff -u src/stdlib_flags.h stage0/src/stdlib_flags.h || exit 1
-    - if: env.should_update_stage0 == 'yes'
-      run: git push origin

.gitignore

@@ -2,10 +2,7 @@
 \#*
 .#*
 *.lock
-.lake
-lake-manifest.json
 build
-!/src/lake/Lake/Build
 GPATH
 GRTAGS
 GSYMS
@@ -28,4 +25,4 @@ fwIn.txt
 fwOut.txt
 wdErr.txt
 wdIn.txt
-wdOut.txt
+wdOut.txt

.gitmodules

@@ -0,0 +1,4 @@
+[submodule "lake"]
+        path = src/lake
+        url = https://github.com/leanprover/lake.git
+        ignore = untracked

.vscode/settings.json

@@ -0,0 +1,7 @@
+{
+    "files.insertFinalNewline": true,
+    "files.trimTrailingWhitespace": true,
+    "[markdown]": {
+        "rewrap.wrappingColumn": 70
+    }
+}

CMakeLists.txt

@@ -11,13 +11,10 @@ foreach(var ${vars})
     list(APPEND STAGE0_ARGS "-D${CMAKE_MATCH_1}=${${var}}")
   elseif("${currentHelpString}" MATCHES "No help, variable specified on the command line." OR "${currentHelpString}" STREQUAL "")
     list(APPEND CL_ARGS "-D${var}=${${var}}")
-    if("${var}" MATCHES "USE_GMP|CHECK_OLEAN_VERSION")
+    if("${var}" STREQUAL "USE_GMP")
       # must forward options that generate incompatible .olean format
       list(APPEND STAGE0_ARGS "-D${var}=${${var}}")
     endif()
-    if("${var}" MATCHES "LLVM*")
-      list(APPEND STAGE0_ARGS "-D${var}=${${var}}")
-    endif()
   elseif(("${var}" MATCHES "CMAKE_.*") AND NOT ("${var}" MATCHES "CMAKE_BUILD_TYPE") AND NOT ("${var}" MATCHES "CMAKE_HOME_DIRECTORY"))
     list(APPEND PLATFORM_ARGS "-D${var}=${${var}}")
   endif()
@@ -26,17 +23,28 @@ endforeach()
 include(ExternalProject)
 project(LEAN CXX C)
 
-if(NOT (DEFINED STAGE0_CMAKE_EXECUTABLE_SUFFIX))
-    set(STAGE0_CMAKE_EXECUTABLE_SUFFIX "${CMAKE_EXECUTABLE_SUFFIX}")
+if("${CMAKE_SYSTEM_NAME}" MATCHES "Emscripten")
+  # For Emscripten, we build GMP before any of the stages and reuse it in all of them.
+  set(GMP_INSTALL_PREFIX ${CMAKE_BINARY_DIR}/gmp-root)
+  set(EMSCRIPTEN_FLAGS "-s ALLOW_MEMORY_GROWTH=1 -s MAIN_MODULE=1 -O3")
+  ExternalProject_Add(
+    gmp
+    URL https://gmplib.org/download/gmp/gmp-6.2.1.tar.bz2
+    URL_HASH SHA256=eae9326beb4158c386e39a356818031bd28f3124cf915f8c5b1dc4c7a36b4d7c
+    BUILD_IN_SOURCE 1
+    CONFIGURE_COMMAND emconfigure ./configure "CFLAGS=${EMSCRIPTEN_FLAGS}" --host=wasm32-unknown-emscripten --disable-assembly --prefix=${GMP_INSTALL_PREFIX}
+    BUILD_COMMAND emmake make -j4
+    INSTALL_COMMAND emmake make install
+  )
+  set(EXTRA_DEPENDS "gmp")
+  list(APPEND CL_ARGS "-DGMP_INSTALL_PREFIX=${GMP_INSTALL_PREFIX}")
+  list(APPEND PLATFORM_ARGS "-DGMP_INSTALL_PREFIX=${GMP_INSTALL_PREFIX}")
 endif()
-
 ExternalProject_add(stage0
   SOURCE_DIR "${LEAN_SOURCE_DIR}/stage0"
   SOURCE_SUBDIR src
   BINARY_DIR stage0
   # do not rebuild stage0 when git hash changes; it's not from this commit anyway
-  # (however, `CHECK_OLEAN_VERSION=ON` in CI will override this as we need to
-  # embed the githash into the stage 1 library built by stage 0)
   CMAKE_ARGS -DSTAGE=0 -DUSE_GITHASH=OFF ${PLATFORM_ARGS} ${STAGE0_ARGS}
   BUILD_ALWAYS ON  # cmake doesn't auto-detect changes without a download method
   INSTALL_COMMAND ""  # skip install
@@ -46,7 +54,7 @@ ExternalProject_add(stage1
   SOURCE_DIR "${LEAN_SOURCE_DIR}"
   SOURCE_SUBDIR src
   BINARY_DIR stage1
-  CMAKE_ARGS -DSTAGE=1 -DPREV_STAGE=${CMAKE_BINARY_DIR}/stage0 -DPREV_STAGE_CMAKE_EXECUTABLE_SUFFIX=${STAGE0_CMAKE_EXECUTABLE_SUFFIX} ${CL_ARGS}
+  CMAKE_ARGS -DSTAGE=1 -DPREV_STAGE=${CMAKE_BINARY_DIR}/stage0 ${CL_ARGS}
   BUILD_ALWAYS ON
   INSTALL_COMMAND ""
   DEPENDS stage0
@@ -55,7 +63,7 @@ ExternalProject_add(stage2
   SOURCE_DIR "${LEAN_SOURCE_DIR}"
   SOURCE_SUBDIR src
   BINARY_DIR stage2
-  CMAKE_ARGS -DSTAGE=2 -DPREV_STAGE=${CMAKE_BINARY_DIR}/stage1 -DPREV_STAGE_CMAKE_EXECUTABLE_SUFFIX=${CMAKE_EXECUTABLE_SUFFIX} ${CL_ARGS}
+  CMAKE_ARGS -DSTAGE=2 -DPREV_STAGE=${CMAKE_BINARY_DIR}/stage1 ${CL_ARGS}
   BUILD_ALWAYS ON
   INSTALL_COMMAND ""
   DEPENDS stage1
@@ -65,7 +73,7 @@ ExternalProject_add(stage3
   SOURCE_DIR "${LEAN_SOURCE_DIR}"
   SOURCE_SUBDIR src
   BINARY_DIR stage3
-  CMAKE_ARGS -DSTAGE=3 -DPREV_STAGE=${CMAKE_BINARY_DIR}/stage2 -DPREV_STAGE_CMAKE_EXECUTABLE_SUFFIX=${CMAKE_EXECUTABLE_SUFFIX} ${CL_ARGS}
+  CMAKE_ARGS -DSTAGE=3 -DPREV_STAGE=${CMAKE_BINARY_DIR}/stage2 ${CL_ARGS}
   BUILD_ALWAYS ON
   INSTALL_COMMAND ""
   DEPENDS stage2

CODEOWNERS

@@ -1,22 +0,0 @@
-# Code Owners
-#
-# Documents responsible people per component.
-# Listed persons will automatically be asked by GitHub to review a PR touching these paths.
-# If multiple names are listed, a review by any of them is considered sufficient by default.
-
-/.github/ @Kha @semorrison
-/RELEASES.md @semorrison
-/src/ @leodemoura @Kha
-/src/Init/IO.lean @joehendrix
-/src/kernel/ @leodemoura
-/src/lake/ @tydeu
-/src/Lean/Compiler/ @leodemoura
-/src/Lean/Data/Lsp/ @mhuisi
-/src/Lean/Elab/Deriving/ @semorrison
-/src/Lean/Elab/Tactic/ @semorrison
-/src/Lean/Meta/Tactic/ @leodemoura
-/src/Lean/Parser/ @Kha
-/src/Lean/PrettyPrinter/ @Kha
-/src/Lean/Server/ @mhuisi
-/src/Lean/Widget/ @Vtec234
-/src/runtime/io.cpp @joehendrix

CONTRIBUTING.md

@@ -1,79 +1,57 @@
-External Contribution Guidelines
-============
+# Contribution Guidelines
 
-In the past, we accepted most pull requests. This practice produced hard to maintain code, performance problems, and bugs. In order to improve the quality and maintainability of our codebase, we've established the following guidelines for external contributions.
+Thank you for your interest in contributing to Lean! There are many ways to contribute and we appreciate all of them.
 
-Helpful links
--------
+## Bug reports
 
-* [Development Setup](./doc/dev/index.md)
-* [Testing](./doc/dev/testing.md)
-* [Commit convention](./doc/dev/commit_convention.md)
+Bug reports as new issues are always welcome. Please check the existing [issues](https://github.com/leanprover/lean4/issues) first.
+Reduce the issue to a self-contained, reproducible test case.
+If you have the chance, before reporting a bug, please search existing issues, as it's possible that
+someone else has already reported your error.
+If you're not sure if something is a bug or not, feel free to file a bug anyway. You may also want to discuss it with the Lean
+community using the [lean4 Zulip channel](https://leanprover.zulipchat.com/#narrow/stream/270676-lean4).
 
-Before You Submit a Pull Request (PR):
--------
+## Simple fixes
 
-**Start with an Issue**: Before submitting a PR, always open an issue discussing the problem you wish to solve or the feature you'd like to add. Use the prefix `RFC:` (request for comments) if you are proposing a new feature. Ask for feedback from other users. Take the time to summarize all the feedback. This allows the maintainers to evaluate your proposal more efficiently. When creating a RFC, consider the following questions:
+Simple fixes for **typos and clear bugs** are welcome.
 
-  - **User Experience**: How does this feature improve the user experience?
+## Documentation
 
-  - **Beneficiaries**: Which Lean users and projects do benefit most from this feature/change?
+Tutorial-like examples are very welcome.
+They are useful for finding rough edges and bugs in Lean 4, for highlighting new features, and for showing how to use Lean.
+If you want to store your tutorial in the Lean 4 repository to make sure future changes will not break it, we suggest the following workflow:
+* Contact one of the Lean developers on Zulip, and check whether your tutorial is a good match for the Lean 4 repository.
+* Send bug reports and report rough edges. We will work with you until the tutorial looks great.
+* Add plenty of comments and make sure others will be able to follow it.
+* Create a pull request in the Lean 4 repository. After merging, we will link it to the official documentation and make sure it becomes part of our test suite.
 
-  - **Community Feedback**: Have you sought feedback or insights from other Lean users?
+You can use `.lean` or `.md` files to create your tutorial. The `.md` files are ideal when you want to format your prose using markdown. For an example, see [this `.md` file](https://github.com/leanprover/lean4/blob/master/doc/lean3changes.md).
 
-  - **Maintainability**: Will this change streamline code maintenance or simplify its structure?
+Contributions to the reference manual are also welcome, but since Lean 4 is changing rapidly, please contact us first using Zulip
+to find out which parts are stable enough to document. We will work with you to get this kind of
+pull request merged. We are also happy to meet using Zoom, Skype or Google hangout to coordinate this kind of effort.
 
-**Understand the Project**: Familiarize yourself with the project, existing issues, and latest commits. Ensure your contribution aligns with the project's direction and priorities.
+As Lean 4 matures, other forms of documentation (e.g., doc-strings) will be welcome too.
 
-**Stay Updated**: Regularly fetch and merge changes from the main branch to ensure your branch is up-to-date and can be smoothly integrated.
+## "Help wanted"
 
-**Help wanted**: We have issues tagged with ["help wanted"](https://github.com/leanprover/lean4/issues?q=is%3Aissue+is%3Aopen+label%3A%22help+wanted%22), if you want to contribute to the project, please take a look at them. If you are interested in one of them, post comments, ask questions, and engage with the core developers there.
+For issues marked as [`help wanted`](https://github.com/leanprover/lean4/issues?q=is%3Aissue+is%3Aopen+label%3A%22help+wanted%22), pull requests (PR) are welcome and we will work with you to get a PR merged. Some of these issues are nontrivial. If you are interested, please consider adding comments to the issue and/or messaging the Lean developers in [Zulip](https://leanprover.zulipchat.com/#).
 
-Quality Over Quantity:
------
+## Unexpected Pull Requests
 
-**Focused Changes**: Each PR should address a single, clearly-defined issue or feature. Avoid making multiple unrelated changes in a single PR.
+We have very few core developers, and we cannot review arbitrary pull requests (PRs). Moreover, many features involve subtle tradeoffs, and it may require significant time and energy to even assess a proposed design. We suggest the following workflow:
 
-**Write Tests**: Every new feature or bug fix should come with relevant tests. This ensures the robustness and reliability of the contribution.
+* First, discuss your idea with the Lean community on Zulip. Ask the community to help collect examples, document the requirements, and detect complications.
+* If there is broad support, create a detailed issue for it on the Lean 4 repository at GitHub, and tag the issue with `RFC`.
+* Ask the community for help documenting the requirements, and for collecting examples and concerns.
+* Wait for one of the core developers to give you a "go ahead". At this point, the core developers will work with you to make sure your PR gets merged.
 
-**Documentation**: Update relevant documentation, including comments in the code, to explain the logic and reasoning behind your changes.
+We don't want to waste your time by you implementing a feature and then us not being able to merge it.
 
-Coding Standards:
-----
+## How to Contribute
 
-**Follow the Code Style**: Ensure that your code follows the established coding style of the project.
-
-**Lean on Lean**: Use Lean's built-in features and libraries effectively, avoiding reinventions.
-
-**Performance**: Make sure that your changes do not introduce performance regressions. If possible, optimize the solution for speed and resource usage.
-
-PR Submission:
----
-
-**Descriptive Title and Summary**: The PR title should briefly explain the purpose of the PR. The summary should give more detailed information on what changes are made and why. Links to Zulip threads are not acceptable as a summary. You are responsible for summarizing the discussion, and getting support for it.
-
-**Follow the commit convention**: Pull requests are squash merged, and the
-commit message is taken from the pull request title and body, so make sure they adhere to the [commit convention](https://github.com/leanprover/lean4/blob/master/doc/dev/commit_convention.md). Put questions and extra information, which should not be part of the final commit message, into a first comment rather than the Pull Request description.
-Because the change will be squashed, there is no need to polish the commit messages and history on the branch.
-
-**Link to Relevant Issues**: Reference any issues that your PR addresses to provide context.
-
-**Stay Responsive**: Once the PR is submitted, stay responsive to feedback and be prepared to make necessary revisions. We will close any PR that has been inactive (no response or updates from the submitter) for more than a month.
-
-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.
-
-**Continuous Integration**: Ensure that all CI checks pass on your PR. Failed checks will delay the review process. The maintainers will not check PRs containing failures.
-
-What to Expect:
-----
-
-**Not All PRs Get Merged**: While we appreciate every contribution, not all PRs will be merged. Ensure your changes align with the project's goals and quality standards.
-
-**Feedback is a Gift**: It helps improve the project and can also help you grow as a developer or contributor.
-
-**Community Involvement**: Engage with the Lean community on our communication channels. This can lead to better collaboration and understanding of the project's direction.
+* Always follow the [commit convention](https://leanprover.github.io/lean4/doc/dev/commit_convention.html).
+* Follow the style of the surrounding code. When in doubt, look at other files using the particular syntax as well.
+* Make sure your code is documented.
+* New features or bug fixes should come with appropriate tests.
+* Ensure all tests work before submitting a PR; see [Development Setup](https://leanprover.github.io/lean4/doc/make/index.html#development-setup) and [Fixing Tests](https://leanprover.github.io/lean4/doc/dev/fixing_tests.html).

README.md

@@ -1,20 +1,22 @@
-This is the repository for **Lean 4**.
+This is the repository for **Lean 4**, which is currently being released as milestone releases towards a first stable release.
+[Lean 3](https://github.com/leanprover/lean) is still the latest stable release.
 
 # About
 
-- [Quickstart](https://lean-lang.org/lean4/doc/quickstart.html)
-- [Homepage](https://lean-lang.org)
-- [Theorem Proving Tutorial](https://lean-lang.org/theorem_proving_in_lean4/)
-- [Functional Programming in Lean](https://lean-lang.org/functional_programming_in_lean/)
-- [Manual](https://lean-lang.org/lean4/doc/)
+- [Quickstart](https://github.com/leanprover/lean4/blob/master/doc/quickstart.md)
+- [Walkthrough installation video](https://www.youtube.com/watch?v=yZo6k48L0VY)
+- [Quick tour video](https://youtu.be/zyXtbb_eYbY)
+- [Homepage](https://leanprover.github.io)
+- [Theorem Proving Tutorial](https://leanprover.github.io/theorem_proving_in_lean4/)
+- [Functional Programming in Lean](https://leanprover.github.io/functional_programming_in_lean/) **first chapter is available!**
+- [Manual](https://leanprover.github.io/lean4/doc/)
 - [Release notes](RELEASES.md) starting at v4.0.0-m3
-- [Examples](https://lean-lang.org/lean4/doc/examples.html)
-- [External Contribution Guidelines](CONTRIBUTING.md)
-- [FAQ](https://lean-lang.org/lean4/doc/faq.html)
+- [Examples](https://leanprover.github.io/lean4/doc/examples.html)
+- [FAQ](https://leanprover.github.io/lean4/doc/faq.html)
 
 # Installation
 
-See [Setting Up Lean](https://lean-lang.org/lean4/doc/setup.html).
+See [Setting Up Lean](https://leanprover.github.io/lean4/doc/setup.html).
 
 # Contributing
 
@@ -22,4 +24,4 @@ Please read our [Contribution Guidelines](CONTRIBUTING.md) first.
 
 # Building from Source
 
-See [Building Lean](https://lean-lang.org/lean4/doc/make/index.html).
+See [Building Lean](https://leanprover.github.io/lean4/doc/make/index.html).

RELEASES.md

@@ -1,569 +1,3 @@
-# Lean 4 releases
-
-We intend to provide regular "minor version" releases of the Lean language at approximately monthly intervals.
-There is not yet a strong guarantee of backwards compatibility between versions,
-only an expectation that breaking changes will be documented in this file.
-
-This file contains work-in-progress notes for the upcoming release, as well as previous stable releases.
-Please check the [releases](https://github.com/leanprover/lean4/releases) page for the current status
-of each version.
-
-v4.7.0 (development in progress)
----------
-
-v4.6.0
----------
-
-* Add custom simplification procedures (aka `simproc`s) to `simp`. Simprocs can be triggered by the simplifier on a specified term-pattern. Here is an small example:
-```lean
-import Lean.Meta.Tactic.Simp.BuiltinSimprocs.Nat
-
-def foo (x : Nat) : Nat :=
-  x + 10
-
-/--
-The `simproc` `reduceFoo` is invoked on terms that match the pattern `foo _`.
--/
-simproc reduceFoo (foo _) :=
-  /- A term of type `Expr → SimpM Step -/
-  fun e => do
-    /-
-    The `Step` type has three constructors: `.done`, `.visit`, `.continue`.
-    * The constructor `.done` instructs `simp` that the result does
-      not need to be simplied further.
-    * The constructor `.visit` instructs `simp` to visit the resulting expression.
-    * The constructor `.continue` instructs `simp` to try other simplification procedures.
-
-    All three constructors take a `Result`. The `.continue` contructor may also take `none`.
-    `Result` has two fields `expr` (the new expression), and `proof?` (an optional proof).
-     If the new expression is definitionally equal to the input one, then `proof?` can be omitted or set to `none`.
-    -/
-    /- `simp` uses matching modulo reducibility. So, we ensure the term is a `foo`-application. -/
-    unless e.isAppOfArity ``foo 1 do
-      return .continue
-    /- `Nat.fromExpr?` tries to convert an expression into a `Nat` value -/
-    let some n ← Nat.fromExpr? e.appArg!
-      | return .continue
-    return .done { expr := Lean.mkNatLit (n+10) }
-```
-We disable simprocs support by using the command `set_option simprocs false`. This command is particularly useful when porting files to v4.6.0.
-Simprocs can be scoped, manually added to `simp` commands, and suppressed using `-`. They are also supported by `simp?`. `simp only` does not execute any `simproc`. Here are some examples for the `simproc` defined above.
-```lean
-example : x + foo 2 = 12 + x := by
-  set_option simprocs false in
-    /- This `simp` command does not make progress since `simproc`s are disabled. -/
-    fail_if_success simp
-  simp_arith
-
-example : x + foo 2 = 12 + x := by
-  /- `simp only` must not use the default simproc set. -/
-  fail_if_success simp only
-  simp_arith
-
-example : x + foo 2 = 12 + x := by
-  /-
-  `simp only` does not use the default simproc set,
-  but we can provide simprocs as arguments. -/
-  simp only [reduceFoo]
-  simp_arith
-
-example : x + foo 2 = 12 + x := by
-  /- We can use `-` to disable `simproc`s. -/
-  fail_if_success simp [-reduceFoo]
-  simp_arith
-```
-The command `register_simp_attr <id>` now creates a `simp` **and** a `simproc` set with the name `<id>`. The following command instructs Lean to insert the `reduceFoo` simplification procedure into the set `my_simp`. If no set is specified, Lean uses the default `simp` set.
-```lean
-simproc [my_simp] reduceFoo (foo _) := ...
-```
-
-* The syntax of the `termination_by` and `decreasing_by` termination hints is overhauled:
-
-  * They are now placed directly after the function they apply to, instead of
-    after the whole `mutual` block.
-  * Therefore, the function name no longer has to be mentioned in the hint.
-  * If the function has a `where` clause, the `termination_by` and
-    `decreasing_by` for that function come before the `where`. The
-    functions in the `where` clause can have their own termination hints, each
-    following the corresponding definition.
-  * The `termination_by` clause can only bind “extra parameters”, that are not
-    already bound by the function header, but are bound in a lambda (`:= fun x
-    y z =>`) or in patterns (`| x, n + 1 => …`). These extra parameters used to
-    be understood as a suffix of the function parameters; now it is a prefix.
-
-  Migration guide: In simple cases just remove the function name, and any
-  variables already bound at the header.
-  ```diff
-   def foo : Nat → Nat → Nat := …
-  -termination_by foo a b => a - b
-  +termination_by a b => a - b
-  ```
-  or
-  ```diff
-   def foo : Nat → Nat → Nat := …
-  -termination_by _ a b => a - b
-  +termination_by a b => a - b
-  ```
-
-  If the parameters are bound in the function header (before the `:`), remove them as well:
-  ```diff
-   def foo (a b : Nat) : Nat := …
-  -termination_by foo a b => a - b
-  +termination_by a - b
-  ```
-
-  Else, if there are multiple extra parameters, make sure to refer to the right
-  ones; the bound variables are interpreted from left to right, no longer from
-  right to left:
-  ```diff
-   def foo : Nat → Nat → Nat → Nat
-     | a, b, c => …
-  -termination_by foo b c => b
-  +termination_by a b => b
-  ```
-
-  In the case of a `mutual` block, place the termination arguments (without the
-  function name) next to the function definition:
-  ```diff
-  -mutual
-  -def foo : Nat → Nat → Nat := …
-  -def bar : Nat → Nat := …
-  -end
-  -termination_by
-  -  foo a b => a - b
-  -  bar a => a
-  +mutual
-  +def foo : Nat → Nat → Nat := …
-  +termination_by a b => a - b
-  +def bar : Nat → Nat := …
-  +termination_by a => a
-  +end
-  ```
-
-  Similarly, if you have (mutual) recursion through `where` or `let rec`, the
-  termination hints are now placed directly after the function they apply to:
-  ```diff
-  -def foo (a b : Nat) : Nat := …
-  -  where bar (x : Nat) : Nat := …
-  -termination_by
-  -  foo a b => a - b
-  -  bar x => x
-  +def foo (a b : Nat) : Nat := …
-  +termination_by a - b
-  +  where
-  +    bar (x : Nat) : Nat := …
-  +    termination_by x
-
-  -def foo (a b : Nat) : Nat :=
-  -  let rec bar (x : Nat) :  Nat := …
-  -  …
-  -termination_by
-  -  foo a b => a - b
-  -  bar x => x
-  +def foo (a b : Nat) : Nat :=
-  +  let rec bar (x : Nat) : Nat := …
-  +    termination_by x
-  +  …
-  +termination_by a - b
-  ```
-
-  In cases where a single `decreasing_by` clause applied to multiple mutually
-  recursive functions before, the tactic now has to be duplicated.
-
-* The semantics of `decreasing_by` changed; the tactic is applied to all
-  termination proof goals together, not individually.
-
-  This helps when writing termination proofs interactively, as one can focus
-  each subgoal individually, for example using `·`. Previously, the given
-  tactic script had to work for _all_ goals, and one had to resort to tactic
-  combinators like `first`:
-
-  ```diff
-   def foo (n : Nat) := … foo e1 … foo e2 …
-  -decreasing_by
-  -simp_wf
-  -first | apply something_about_e1; …
-  -      | apply something_about_e2; …
-  +decreasing_by
-  +all_goals simp_wf
-  +· apply something_about_e1; …
-  +· apply something_about_e2; …
-  ```
-
-  To obtain the old behaviour of applying a tactic to each goal individually,
-  use `all_goals`:
-  ```diff
-   def foo (n : Nat) := …
-  -decreasing_by some_tactic
-  +decreasing_by all_goals some_tactic
-  ```
-
-  In the case of mutual recursion each `decreasing_by` now applies to just its
-  function. If some functions in a recursive group do not have their own
-  `decreasing_by`, the default `decreasing_tactic` is used. If the same tactic
-  ought to be applied to multiple functions, the `decreasing_by` clause has to
-  be repeated at each of these functions.
-
-* Modify `InfoTree.context` to facilitate augmenting it with partial contexts while elaborating a command. This breaks backwards compatibility with all downstream projects that traverse the `InfoTree` manually instead of going through the functions in `InfoUtils.lean`, as well as those manually creating and saving `InfoTree`s. See [PR #3159](https://github.com/leanprover/lean4/pull/3159) for how to migrate your code.
-
-* Add language server support for [call hierarchy requests](https://www.youtube.com/watch?v=r5LA7ivUb2c) ([PR #3082](https://github.com/leanprover/lean4/pull/3082)). The change to the .ilean format in this PR means that projects must be fully rebuilt once in order to generate .ilean files with the new format before features like "find references" work correctly again.
-
-* Structure instances with multiple sources (for example `{a, b, c with x := 0}`) now have their fields filled from these sources
-  in strict left-to-right order. Furthermore, the structure instance elaborator now aggressively use sources to fill in subobject
-  fields, which prevents unnecessary eta expansion of the sources,
-  and hence greatly reduces the reliance on costly structure eta reduction. This has a large impact on mathlib,
-  reducing total CPU instructions by 3% and enabling impactful refactors like leanprover-community/mathlib4#8386
-  which reduces the build time by almost 20%.
-  See PR [#2478](https://github.com/leanprover/lean4/pull/2478) and RFC [#2451](https://github.com/leanprover/lean4/issues/2451).
-
-* Add pretty printer settings to omit deeply nested terms (`pp.deepTerms false` and `pp.deepTerms.threshold`) ([PR #3201](https://github.com/leanprover/lean4/pull/3201))
-
-* Add pretty printer options `pp.numeralTypes` and `pp.natLit`.
-  When `pp.numeralTypes` is true, then natural number literals, integer literals, and rational number literals
-  are pretty printed with type ascriptions, such as `(2 : Rat)`, `(-2 : Rat)`, and `(-2 / 3 : Rat)`.
-  When `pp.natLit` is true, then raw natural number literals are pretty printed as `nat_lit 2`.
-  [PR #2933](https://github.com/leanprover/lean4/pull/2933) and [RFC #3021](https://github.com/leanprover/lean4/issues/3021).
-
-Lake updates:
-* improved platform information & control [#3226](https://github.com/leanprover/lean4/pull/3226)
-* `lake update` from unsupported manifest versions [#3149](https://github.com/leanprover/lean4/pull/3149)
-
-Other improvements:
-* make `intro` be aware of `let_fun` [#3115](https://github.com/leanprover/lean4/pull/3115)
-* produce simpler proof terms in `rw` [#3121](https://github.com/leanprover/lean4/pull/3121)
-* fuse nested `mkCongrArg` calls in proofs generated by `simp` [#3203](https://github.com/leanprover/lean4/pull/3203)
-* `induction using` followed by a general term [#3188](https://github.com/leanprover/lean4/pull/3188)
-* allow generalization in `let` [#3060](https://github.com/leanprover/lean4/pull/3060, fixing [#3065](https://github.com/leanprover/lean4/issues/3065)
-* reducing out-of-bounds `swap!` should return `a`, not `default`` [#3197](https://github.com/leanprover/lean4/pull/3197), fixing [#3196](https://github.com/leanprover/lean4/issues/3196)
-* derive `BEq` on structure with `Prop`-fields [#3191](https://github.com/leanprover/lean4/pull/3191), fixing [#3140](https://github.com/leanprover/lean4/issues/3140)
-* refine through more `casesOnApp`/`matcherApp` [#3176](https://github.com/leanprover/lean4/pull/3176), fixing [#3175](https://github.com/leanprover/lean4/pull/3175)
-* do not strip dotted components from lean module names [#2994](https://github.com/leanprover/lean4/pull/2994), fixing [#2999](https://github.com/leanprover/lean4/issues/2999)
-* fix `deriving` only deriving the first declaration for some handlers [#3058](https://github.com/leanprover/lean4/pull/3058), fixing [#3057](https://github.com/leanprover/lean4/issues/3057)
-* do not instantiate metavariables in kabstract/rw for disallowed occurrences [#2539](https://github.com/leanprover/lean4/pull/2539), fixing [#2538](https://github.com/leanprover/lean4/issues/2538)
-* hover info for `cases h : ...` [#3084](https://github.com/leanprover/lean4/pull/3084)
-
-v4.5.0
----------
-
-* Modify the lexical syntax of string literals to have string gaps, which are escape sequences of the form `"\" newline whitespace*`.
-  These have the interpetation of an empty string and allow a string to flow across multiple lines without introducing additional whitespace.
-  The following is equivalent to `"this is a string"`.
-  ```lean
-  "this is \
-     a string"
-  ```
-  [PR #2821](https://github.com/leanprover/lean4/pull/2821) and [RFC #2838](https://github.com/leanprover/lean4/issues/2838).
-
-* Add raw string literal syntax. For example, `r"\n"` is equivalent to `"\\n"`, with no escape processing.
-  To include double quote characters in a raw string one can add sufficiently many `#` characters before and after
-  the bounding `"`s, as in `r#"the "the" is in quotes"#` for `"the \"the\" is in quotes"`.
-  [PR #2929](https://github.com/leanprover/lean4/pull/2929) and [issue #1422](https://github.com/leanprover/lean4/issues/1422).
-
-* The low-level `termination_by'` clause is no longer supported.
-
-  Migration guide: Use `termination_by` instead, e.g.:
-  ```diff
-  -termination_by' measure (fun ⟨i, _⟩ => as.size - i)
-  +termination_by i _ => as.size - i
-  ```
-
-  If the well-founded relation you want to use is not the one that the
-  `WellFoundedRelation` type class would infer for your termination argument,
-  you can use `WellFounded.wrap` from the std libarary to explicitly give one:
-  ```diff
-  -termination_by' ⟨r, hwf⟩
-  +termination_by x => hwf.wrap x
-  ```
-
-* Support snippet edits in LSP `TextEdit`s. See `Lean.Lsp.SnippetString` for more details.
-
-* Deprecations and changes in the widget API.
-  - `Widget.UserWidgetDefinition` is deprecated in favour of `Widget.Module`. The annotation `@[widget]` is deprecated in favour of `@[widget_module]`. To migrate a definition of type `UserWidgetDefinition`, remove the `name` field and replace the type with `Widget.Module`. Removing the `name` results in a title bar no longer being drawn above your panel widget. To add it back, draw it as part of the component using `<details open=true><summary class='mv2 pointer'>{name}</summary>{rest_of_widget}</details>`. See an example migration [here](https://github.com/leanprover/std4/pull/475/files#diff-857376079661a0c28a53b7ff84701afabbdf529836a6944d106c5294f0e68109R43-R83).
-  - The new command `show_panel_widgets` allows displaying always-on and locally-on panel widgets.
-  - `RpcEncodable` widget props can now be stored in the infotree.
-  - See [RFC 2963](https://github.com/leanprover/lean4/issues/2963) for more details and motivation.
-
-* If no usable lexicographic order can be found automatically for a termination proof, explain why.
-  See [feat: GuessLex: if no measure is found, explain why](https://github.com/leanprover/lean4/pull/2960).
-
-* Option to print [inferred termination argument](https://github.com/leanprover/lean4/pull/3012).
-  With `set_option showInferredTerminationBy true` you will get messages like
-  ```
-  Inferred termination argument:
-  termination_by
-  ackermann n m => (sizeOf n, sizeOf m)
-  ```
-  for automatically generated `termination_by` clauses.
-
-* More detailed error messages for [invalid mutual blocks](https://github.com/leanprover/lean4/pull/2949).
-
-* [Multiple](https://github.com/leanprover/lean4/pull/2923) [improvements](https://github.com/leanprover/lean4/pull/2969) to the output of `simp?` and `simp_all?`.
-
-* Tactics with `withLocation *` [no longer fail](https://github.com/leanprover/lean4/pull/2917) if they close the main goal.
-
-* Implementation of a `test_extern` command for writing tests for `@[extern]` and `@[implemented_by]` functions.
-  Usage is
-  ```
-  import Lean.Util.TestExtern
-
-  test_extern Nat.add 17 37
-  ```
-  The head symbol must be the constant with the `@[extern]` or `@[implemented_by]` attribute. The return type must have a `DecidableEq` instance.
-
-Bug fixes for
-[#2853](https://github.com/leanprover/lean4/issues/2853), [#2953](https://github.com/leanprover/lean4/issues/2953), [#2966](https://github.com/leanprover/lean4/issues/2966),
-[#2971](https://github.com/leanprover/lean4/issues/2971), [#2990](https://github.com/leanprover/lean4/issues/2990), [#3094](https://github.com/leanprover/lean4/issues/3094).
-
-Bug fix for [eager evaluation of default value](https://github.com/leanprover/lean4/pull/3043) in `Option.getD`.
-Avoid [panic in `leanPosToLspPos`](https://github.com/leanprover/lean4/pull/3071) when file source is unavailable.
-Improve [short-circuiting behavior](https://github.com/leanprover/lean4/pull/2972) for `List.all` and `List.any`.
-
-Several Lake bug fixes: [#3036](https://github.com/leanprover/lean4/issues/3036), [#3064](https://github.com/leanprover/lean4/issues/3064), [#3069](https://github.com/leanprover/lean4/issues/3069).
-
-v4.4.0
----------
-
-* Lake and the language server now support per-package server options using the `moreServerOptions` config field, as well as options that apply to both the language server and `lean` using the `leanOptions` config field. Setting either of these fields instead of `moreServerArgs` ensures that viewing files from a dependency uses the options for that dependency. Additionally, `moreServerArgs` is being deprecated in favor of the `moreGlobalServerArgs` field. See PR [#2858](https://github.com/leanprover/lean4/pull/2858).
-
-  A Lakefile with the following deprecated package declaration:
-  ```lean
-  def moreServerArgs := #[
-    "-Dpp.unicode.fun=true"
-  ]
-  def moreLeanArgs := moreServerArgs
-
-  package SomePackage where
-    moreServerArgs := moreServerArgs
-    moreLeanArgs := moreLeanArgs
-  ```
-
-  ... can be updated to the following package declaration to use per-package options:
-  ```lean
-  package SomePackage where
-    leanOptions := #[⟨`pp.unicode.fun, true⟩]
-  ```
-* [Rename request handler](https://github.com/leanprover/lean4/pull/2462).
-* [Import auto-completion](https://github.com/leanprover/lean4/pull/2904).
-* [`pp.beta`` to apply beta reduction when pretty printing](https://github.com/leanprover/lean4/pull/2864).
-* [Embed and check githash in .olean](https://github.com/leanprover/lean4/pull/2766).
-* [Guess lexicographic order for well-founded recursion](https://github.com/leanprover/lean4/pull/2874).
-* [Allow trailing comma in tuples, lists, and tactics](https://github.com/leanprover/lean4/pull/2643).
-
-Bug fixes for [#2628](https://github.com/leanprover/lean4/issues/2628), [#2883](https://github.com/leanprover/lean4/issues/2883),
-[#2810](https://github.com/leanprover/lean4/issues/2810), [#2925](https://github.com/leanprover/lean4/issues/2925), and [#2914](https://github.com/leanprover/lean4/issues/2914).
-
-**Lake:**
-
-* `lake init .` and a bare `lake init` and will now use the current directory as the package name. [#2890](https://github.com/leanprover/lean4/pull/2890)
-* `lake new` and `lake init` will now produce errors on invalid package names such as `..`, `foo/bar`, `Init`, `Lean`, `Lake`, and `Main`. See issue [#2637](https://github.com/leanprover/lean4/issues/2637) and PR [#2890](https://github.com/leanprover/lean4/pull/2890).
-* `lean_lib` no longer converts its name to upper camel case (e.g., `lean_lib bar` will include modules named `bar.*` rather than `Bar.*`). See issue [#2567](https://github.com/leanprover/lean4/issues/2567) and PR [#2889](https://github.com/leanprover/lean4/pull/2889).
-* Lean and Lake now properly support non-identifier library names (e.g., `lake new 123-hello` and `import «123Hello»` now work correctly). See issue [#2865](https://github.com/leanprover/lean4/issues/2865) and PR [#2889](https://github.com/leanprover/lean4/pull/2888).
-* Lake now filters the environment extensions loaded from a compiled configuration (`lakefile.olean`) to include only those relevant to Lake's workspace loading process. This resolves segmentation faults caused by environment extension type mismatches (e.g., when defining custom elaborators via `elab` in configurations). See issue [#2632](https://github.com/leanprover/lean4/issues/2632) and PR [#2896](https://github.com/leanprover/lean4/pull/2896).
-* Cloud releases will now properly be re-unpacked if the build directory is removed. See PR [#2928](https://github.com/leanprover/lean4/pull/2928).
-* Lake's `math` template has been simplified. See PR [#2930](https://github.com/leanprover/lean4/pull/2930).
-* `lake exe <target>` now parses `target` like a build target (as the help text states it should) rather than as a basic name. For example, `lake exe @mathlib/runLinter` should now work. See PR [#2932](https://github.com/leanprover/lean4/pull/2932).
-* `lake new foo.bar [std]` now generates executables named `foo-bar` and `lake new foo.bar exe` properly creates `foo/bar.lean`. See PR [#2932](https://github.com/leanprover/lean4/pull/2932).
-* Later packages and libraries in the dependency tree are now preferred over earlier ones. That is, the later ones "shadow" the earlier ones. Such an ordering is more consistent with how declarations generally work in programming languages. This will break any package that relied on the previous ordering. See issue [#2548](https://github.com/leanprover/lean4/issues/2548) and PR [#2937](https://github.com/leanprover/lean4/pull/2937).
-* Executable roots are no longer mistakenly treated as importable. They will no longer be picked up by `findModule?`. See PR [#2937](https://github.com/leanprover/lean4/pull/2937).
-
-v4.3.0
----------
-
-* `simp [f]` does not unfold partial applications of `f` anymore. See issue [#2042](https://github.com/leanprover/lean4/issues/2042).
-  To fix proofs affected by this change, use `unfold f` or `simp (config := { unfoldPartialApp := true }) [f]`.
-* By default, `simp` will no longer try to use Decidable instances to rewrite terms. In particular, not all decidable goals will be closed by `simp`, and the `decide` tactic may be useful in such cases. The `decide` simp configuration option can be used to locally restore the old `simp` behavior, as in `simp (config := {decide := true})`; this includes using Decidable instances to verify side goals such as numeric inequalities.
-
-* Many bug fixes:
-  * [Add left/right actions to term tree coercion elaborator and make `^`` a right action](https://github.com/leanprover/lean4/pull/2778)
-  * [Fix for #2775, don't catch max recursion depth errors](https://github.com/leanprover/lean4/pull/2790)
-  * [Reduction of `Decidable` instances very slow when using `cases` tactic](https://github.com/leanprover/lean4/issues/2552)
-  * [`simp` not rewriting in binder](https://github.com/leanprover/lean4/issues/1926)
-  * [`simp` unfolding `let` even with `zeta := false` option](https://github.com/leanprover/lean4/issues/2669)
-  * [`simp` (with beta/zeta disabled) and discrimination trees](https://github.com/leanprover/lean4/issues/2281)
-  * [unknown free variable introduced by `rw ... at h`](https://github.com/leanprover/lean4/issues/2711)
-  * [`dsimp` doesn't use `rfl` theorems which consist of an unapplied constant](https://github.com/leanprover/lean4/issues/2685)
-  * [`dsimp` does not close reflexive equality goals if they are wrapped in metadata](https://github.com/leanprover/lean4/issues/2514)
-  * [`rw [h]` uses `h` from the environment in preference to `h` from the local context](https://github.com/leanprover/lean4/issues/2729)
-  * [missing `withAssignableSyntheticOpaque` for `assumption` tactic](https://github.com/leanprover/lean4/issues/2361)
-  * [ignoring default value for field warning](https://github.com/leanprover/lean4/issues/2178)
-* [Cancel outstanding tasks on document edit in the language server](https://github.com/leanprover/lean4/pull/2648).
-* [Remove unnecessary `%` operations in `Fin.mod` and `Fin.div`](https://github.com/leanprover/lean4/pull/2688)
-* [Avoid `DecidableEq` in `Array.mem`](https://github.com/leanprover/lean4/pull/2774)
-* [Ensure `USize.size` unifies with `?m + 1`](https://github.com/leanprover/lean4/issues/1926)
-* [Improve compatibility with emacs eglot client](https://github.com/leanprover/lean4/pull/2721)
-
-**Lake:**
-
-* [Sensible defaults for `lake new MyProject math`](https://github.com/leanprover/lean4/pull/2770)
-* Changed `postUpdate?` configuration option to a `post_update` declaration. See the `post_update` syntax docstring for more information on the new syntax.
-* [A manifest is automatically created on workspace load if one does not exists.](https://github.com/leanprover/lean4/pull/2680).
-* The `:=` syntax for configuration declarations (i.e., `package`, `lean_lib`, and `lean_exe`) has been deprecated. For example, `package foo := {...}` is deprecated.
-* [support for overriding package URLs via `LAKE_PKG_URL_MAP`](https://github.com/leanprover/lean4/pull/2709)
-* Moved the default build directory (e.g., `build`), default packages directory (e.g., `lake-packages`), and the compiled configuration (e.g., `lakefile.olean`) into a new dedicated directory for Lake outputs, `.lake`. The cloud release build archives are also stored here, fixing [#2713](https://github.com/leanprover/lean4/issues/2713).
-* Update manifest format to version 7 (see [lean4#2801](https://github.com/leanprover/lean4/pull/2801) for details on the changes).
-* Deprecate the `manifestFile` field of a package configuration.
-* There is now a more rigorous check on `lakefile.olean` compatibility (see [#2842](https://github.com/leanprover/lean4/pull/2842) for more details).
-
-v4.2.0
----------
-
-* [isDefEq cache for terms not containing metavariables.](https://github.com/leanprover/lean4/pull/2644).
-* Make [`Environment.mk`](https://github.com/leanprover/lean4/pull/2604) and [`Environment.add`](https://github.com/leanprover/lean4/pull/2642) private, and add [`replay`](https://github.com/leanprover/lean4/pull/2617) as a safer alternative.
-* `IO.Process.output` no longer inherits the standard input of the caller.
-* [Do not inhibit caching](https://github.com/leanprover/lean4/pull/2612) of default-level `match` reduction.
-* [List the valid case tags](https://github.com/leanprover/lean4/pull/2629) when the user writes an invalid one.
-* The derive handler for `DecidableEq` [now handles](https://github.com/leanprover/lean4/pull/2591) mutual inductive types.
-* [Show path of failed import in Lake](https://github.com/leanprover/lean4/pull/2616).
-* [Fix linker warnings on macOS](https://github.com/leanprover/lean4/pull/2598).
-* **Lake:** Add `postUpdate?` package configuration option. Used by a package to specify some code which should be run after a successful `lake update` of the package or one of its downstream dependencies. ([lake#185](https://github.com/leanprover/lake/issues/185))
-* Improvements to Lake startup time ([#2572](https://github.com/leanprover/lean4/pull/2572), [#2573](https://github.com/leanprover/lean4/pull/2573))
-* `refine e` now replaces the main goal with metavariables which were created during elaboration of `e` and no longer captures pre-existing metavariables that occur in `e` ([#2502](https://github.com/leanprover/lean4/pull/2502)).
-  * This is accomplished via changes to `withCollectingNewGoalsFrom`, which also affects `elabTermWithHoles`, `refine'`, `calc` (tactic), and `specialize`. Likewise, all of these now only include newly-created metavariables in their output.
-  * Previously, both newly-created and pre-existing metavariables occurring in `e` were returned inconsistently in different edge cases, causing duplicated goals in the infoview (issue [#2495](https://github.com/leanprover/lean4/issues/2495)), erroneously closed goals (issue [#2434](https://github.com/leanprover/lean4/issues/2434)), and unintuitive behavior due to `refine e` capturing previously-created goals appearing unexpectedly in `e` (no issue; see PR).
-
-v4.1.0
----------
-
-* The error positioning on missing tokens has been [improved](https://github.com/leanprover/lean4/pull/2393). In particular, this should make it easier to spot errors in incomplete tactic proofs.
-
-* After elaborating a configuration file, Lake will now cache the configuration to a `lakefile.olean`. Subsequent runs of Lake will import this OLean instead of elaborating the configuration file. This provides a significant performance improvement (benchmarks indicate that using the OLean cuts Lake's startup time in half), but there are some important details to keep in mind:
-  + Lake will regenerate this OLean after each modification to the `lakefile.lean` or `lean-toolchain`. You can also force a reconfigure by passing the new `--reconfigure` / `-R` option to `lake`.
-  + Lake configuration options (i.e., `-K`) will be fixed at the moment of elaboration. Setting these options when `lake` is using the cached configuration will have no effect. To change options, run `lake` with `-R` / `--reconfigure`.
-  + **The `lakefile.olean` is a local configuration and should not be committed to Git. Therefore, existing Lake packages need to add it to their `.gitignore`.**
-
-* The signature of `Lake.buildO` has changed, `args` has been split into `weakArgs` and `traceArgs`. `traceArgs` are included in the input trace and `weakArgs` are not. See Lake's [FFI example](src/lake/examples/ffi/lib/lakefile.lean) for a demonstration of how to adapt to this change.
-
-* The signatures of `Lean.importModules`, `Lean.Elab.headerToImports`, and `Lean.Elab.parseImports`
-  have [changed](https://github.com/leanprover/lean4/pull/2480) from taking `List Import` to `Array Import`.
-
-* There is now [an `occs` field](https://github.com/leanprover/lean4/pull/2470)
-  in the configuration object for the `rewrite` tactic,
-  allowing control of which occurrences of a pattern should be rewritten.
-  This was previously a separate argument for `Lean.MVarId.rewrite`,
-  and this has been removed in favour of an additional field of `Rewrite.Config`.
-  It was not previously accessible from user tactics.
-
-v4.0.0
----------
-
-* [`Lean.Meta.getConst?` has been renamed](https://github.com/leanprover/lean4/pull/2454).
-  We have renamed `getConst?` to `getUnfoldableConst?` (and `getConstNoEx?` to `getUnfoldableConstNoEx?`).
-  These were not intended to be part of the public API, but downstream projects had been using them
-  (sometimes expecting different behaviour) incorrectly instead of `Lean.getConstInfo`.
-
-* [`dsimp` / `simp` / `simp_all` now fail by default if they make no progress](https://github.com/leanprover/lean4/pull/2336).
-
-  This can be overridden with the `(config := { failIfUnchanged := false })` option.
-  This change was made to ease manual use of `simp` (with complicated goals it can be hard to tell if it was effective)
-  and to allow easier flow control in tactics internally using `simp`.
-  See the [summary discussion](https://leanprover.zulipchat.com/#narrow/stream/270676-lean4/topic/simp.20fails.20if.20no.20progress/near/380153295)
-  on zulip for more details.
-
-* [`simp_all` now preserves order of hypotheses](https://github.com/leanprover/lean4/pull/2334).
-
-  In order to support the `failIfUnchanged` configuration option for `dsimp` / `simp` / `simp_all`
-  the way `simp_all` replaces hypotheses has changed.
-  In particular it is now more likely to preserve the order of hypotheses.
-  See [`simp_all` reorders hypotheses unnecessarily](https://github.com/leanprover/lean4/pull/2334).
-  (Previously all non-dependent propositional hypotheses were reverted and reintroduced.
-  Now only such hypotheses which were changed, or which come after a changed hypothesis,
-  are reverted and reintroduced.
-  This has the effect of preserving the ordering amongst the non-dependent propositional hypotheses,
-  but now any dependent or non-propositional hypotheses retain their position amongst the unchanged
-  non-dependent propositional hypotheses.)
-  This may affect proofs that use `rename_i`, `case ... =>`, or `next ... =>`.
-
-* [New `have this` implementation](https://github.com/leanprover/lean4/pull/2247).
-
-  `this` is now a regular identifier again that is implicitly introduced by anonymous `have :=` for the remainder of the tactic block. It used to be a keyword that was visible in all scopes and led to unexpected behavior when explicitly used as a binder name.
-
-* [Show typeclass and tactic names in profile output](https://github.com/leanprover/lean4/pull/2170).
-
-* [Make `calc` require the sequence of relation/proof-s to have the same indentation](https://github.com/leanprover/lean4/pull/1844),
-  and [add `calc` alternative syntax allowing underscores `_` in the first relation](https://github.com/leanprover/lean4/pull/1844).
-
-  The flexible indentation in `calc` was often used to align the relation symbols:
-  ```lean
-  example (x y : Nat) : (x + y) * (x + y) = x * x + y * x + x * y + y * y :=
-    calc
-        (x + y) * (x + y) = (x + y) * x + (x + y) * y       := by rw [Nat.mul_add]
-                        -- improper indentation
-                        _ = x * x + y * x + (x + y) * y     := by rw [Nat.add_mul]
-                        _ = x * x + y * x + (x * y + y * y) := by rw [Nat.add_mul]
-                        _ = x * x + y * x + x * y + y * y   := by rw [←Nat.add_assoc]
-  ```
-
-  This is no longer legal.  The new syntax puts the first term right after the `calc` and each step has the same indentation:
-  ```lean
-  example (x y : Nat) : (x + y) * (x + y) = x * x + y * x + x * y + y * y :=
-    calc (x + y) * (x + y)
-      _ = (x + y) * x + (x + y) * y       := by rw [Nat.mul_add]
-      _ = x * x + y * x + (x + y) * y     := by rw [Nat.add_mul]
-      _ = x * x + y * x + (x * y + y * y) := by rw [Nat.add_mul]
-      _ = x * x + y * x + x * y + y * y   := by rw [←Nat.add_assoc]
-  ```
-
-
-* Update Lake to latest prerelease.
-
-* [Make go-to-definition on a typeclass projection application go to the instance(s)](https://github.com/leanprover/lean4/pull/1767).
-
-* [Include timings in trace messages when `profiler` is true](https://github.com/leanprover/lean4/pull/1995).
-
-* [Pretty-print signatures in hover and `#check <ident>`](https://github.com/leanprover/lean4/pull/1943).
-
-* [Introduce parser memoization to avoid exponential behavior](https://github.com/leanprover/lean4/pull/1799).
-
-* [feat: allow `doSeq` in `let x <- e | seq`](https://github.com/leanprover/lean4/pull/1809).
-
-* [Add hover/go-to-def/refs for options](https://github.com/leanprover/lean4/pull/1783).
-
-* [Add empty type ascription syntax `(e :)`](https://github.com/leanprover/lean4/pull/1797).
-
-* [Make tokens in `<|>` relevant to syntax match](https://github.com/leanprover/lean4/pull/1744).
-
-* [Add `linter.deprecated` option to silence deprecation warnings](https://github.com/leanprover/lean4/pull/1768).
-
-* [Improve fuzzy-matching heuristics](https://github.com/leanprover/lean4/pull/1710).
-
-* [Implementation-detail hypotheses](https://github.com/leanprover/lean4/pull/1692).
-
-* [Hover information for `cases`/`induction` case names](https://github.com/leanprover/lean4/pull/1660).
-
-* [Prefer longer parse even if unsuccessful](https://github.com/leanprover/lean4/pull/1658).
-
-* [Show declaration module in hover](https://github.com/leanprover/lean4/pull/1638).
-
-* [New `conv` mode structuring tactics](https://github.com/leanprover/lean4/pull/1636).
-
-* `simp` can track information and can print an equivalent `simp only`. [PR #1626](https://github.com/leanprover/lean4/pull/1626).
-
-* Enforce uniform indentation in tactic blocks / do blocks. See issue [#1606](https://github.com/leanprover/lean4/issues/1606).
-
-* Moved `AssocList`, `HashMap`, `HashSet`, `RBMap`, `RBSet`, `PersistentArray`, `PersistentHashMap`, `PersistentHashSet` to the Lean package. The [standard library](https://github.com/leanprover/std4) contains versions that will evolve independently to simplify bootstrapping process.
-
-* Standard library moved to the [std4 GitHub repository](https://github.com/leanprover/std4).
-
-* `InteractiveGoals` now has information that a client infoview can use to show what parts of the goal have changed after applying a tactic. [PR #1610](https://github.com/leanprover/lean4/pull/1610).
-
-* Add `[inheritDoc]` attribute. [PR #1480](https://github.com/leanprover/lean4/pull/1480).
-
-* Expose that `panic = default`. [PR #1614](https://github.com/leanprover/lean4/pull/1614).
-
-* New [code generator](https://github.com/leanprover/lean4/tree/master/src/Lean/Compiler/LCNF) project has started.
-
-* Remove description argument from `register_simp_attr`. [PR #1566](https://github.com/leanprover/lean4/pull/1566).
-
-* [Additional concurrency primitives](https://github.com/leanprover/lean4/pull/1555).
-
-* [Collapsible traces with messages](https://github.com/leanprover/lean4/pull/1448).
-
-* [Hygienic resolution of namespaces](https://github.com/leanprover/lean4/pull/1442).
-
-* [New `Float` functions](https://github.com/leanprover/lean4/pull/1460).
-
-* Many new doc strings have been added to declarations at `Init`.
-
 v4.0.0-m5 (07 August 2022)
 ---------
 
@@ -1072,7 +506,7 @@ v4.0.0-m5 (07 August 2022)
   `Foo : {Foo : Type u} → List Foo → Type`.
 
 
-* Fix syntax highlighting for recursive declarations. Example
+* Fix syntax hightlighting for recursive declarations. Example
   ```lean
   inductive List (α : Type u) where
     | nil : List α  -- `List` is not highlighted as a variable anymore
@@ -1125,7 +559,7 @@ v4.0.0-m5 (07 August 2022)
     ...
   ```
 
-* Remove support for `{}` annotation from inductive datatype constructors. This annotation was barely used, and we can control the binder information for parameter bindings using the new inductive family indices to parameter promotion. Example: the following declaration using `{}`
+* Remove support for `{}` annotation from inductive datatype contructors. This annotation was barely used, and we can control the binder information for parameter bindings using the new inductive family indices to parameter promotion. Example: the following declaration using `{}`
   ```lean
   inductive LE' (n : Nat) : Nat → Prop where
     | refl {} : LE' n n -- Want `n` to be explicit
@@ -1290,7 +724,7 @@ v4.0.0-m4 (23 March 2022)
 
   initialize my_ext : SimpExtension ← registerSimpAttr `my_simp "my own simp attribute"
   ```
-  If you don't need to access `my_ext`, you can also use the macro
+  If you don't neet to acces `my_ext`, you can also use the macro
   ```lean
   import Lean
 
@@ -1381,7 +815,7 @@ For example, given `f : Nat → Nat` and `g : Nat → Nat`, `f.comp g` is now no
 
 * Various improvements to go-to-definition & find-all-references accuracy.
 
-* Auto generated congruence lemmas with support for casts on proofs and `Decidable` instances (see [wishlist](https://github.com/leanprover/lean4/issues/988)).
+* Auto generated congruence lemmas with support for casts on proofs and `Decidable` instances (see [whishlist](https://github.com/leanprover/lean4/issues/988)).
 
 * Rename option `autoBoundImplicitLocal` => `autoImplicit`.
 

doc/SUMMARY.md

@@ -75,7 +75,6 @@
 - [Significant Changes from Lean 3](./lean3changes.md)
 - [Syntax Highlighting Lean in LaTeX](./syntax_highlight_in_latex.md)
 - [User Widgets](examples/widgets.lean.md)
-- [Semantic Highlighting](./semantic_highlighting.md)
 
 # Development
 
@@ -85,6 +84,7 @@
   - [macOS Setup](./make/osx-10.9.md)
   - [Windows MSYS2 Setup](./make/msys2.md)
   - [Windows with WSL](./make/wsl.md)
+  - [Nix Setup (*Experimental*)](./make/nix.md)
 - [Bootstrapping](./dev/bootstrap.md)
 - [Testing](./dev/testing.md)
 - [Debugging](./dev/debugging.md)

doc/autobound.md

@@ -43,5 +43,3 @@ set_option autoImplicit false
 -- def compose (g : β → γ) (f : α → β) (x : α) : γ :=
 --   g (f x)
 ```
-The Lean language server provides [semantic highlighting](./semantic_highlighting.md) information to editors, and it provides
-visual feedback whether an identifier has been interpreted as an auto bound implicit argument.

doc/bin/README.md

@@ -11,4 +11,4 @@ the following command executes a simple set of examples
 
 % bin/lean examples/ex.lean
 
-For more information on Lean and supported editors, please see https://lean-lang.org/documentation/.
+For more information on Lean and supported editors, please see https://leanprover.github.io/documentation/.

doc/dev/bootstrap.md

@@ -65,36 +65,9 @@ You now have a Lean binary and library that include your changes, though their
 own compilation was not influenced by them, that you can use to test your
 changes on test programs whose compilation *will* be influenced by the changes.
 
-## Updating stage0
-
 Finally, when we want to use new language features in the library, we need to
-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 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/nomeata/lean4/actions/workflows/update-stage0.yml>
-or using Github CLI with
-```
-gh workflow run update-stage0.yml
-```
-
-Leaving stage0 updates to the CI automation is preferrable, but should you need
-to do it locally, you can use `make update-stage0` in `build/release`, to
-update `stage0` from `stage1`, `make -C stageN update-stage0` to update from
-another stage, or `nix run .#update-stage0-commit` to update using nix.
-
-Updates to `stage0` should be their own commits in the Git history. So should
-you have to include the stage0 update in your PR (rather than using above
-automation after merging changes), commit your work before running `make
-update-stage0`, commit the updated `stage0` compiler code with the commit
-message:
-```
-chore: update stage0
-```
-and coordinate with the admins to not squash your PR.
+update the stage 0 compiler, which can be done via `make -C stageN update-stage0`.
+`make update-stage0` without `-C` defaults to stage1.
 
 ## Further Bootstrapping Complications
 

doc/dev/commit_convention.md

@@ -1,15 +1,10 @@
 Git Commit Convention
 =====================
 
-We are using the following convention for writing git commit messages. For pull
-requests, make sure the pull request title and description follow this
-convention, as the squash-merge commit will inherit title and body from the
-pull request.
-
-This convention is based on the one from the AngularJS project ([doc][angularjs-doc],
+We are using the following convention for writing git-commit messages.
+It is based on the one from AngularJS project([doc][angularjs-doc],
 [commits][angularjs-git]).
 
-
 [angularjs-git]: https://github.com/angular/angular.js/commits/master
 [angularjs-doc]: https://docs.google.com/document/d/1QrDFcIiPjSLDn3EL15IJygNPiHORgU1_OOAqWjiDU5Y/edit#
 

doc/dev/ffi.md

@@ -11,8 +11,6 @@ There are two primary attributes for interoperating with other languages:
   It can also be used with `def` to provide an internal definition, but ensuring consistency of both definitions is up to the user.
 * `@[export sym] def leanSym : ...` exports `leanSym` under the unmangled symbol name `sym`.
 
-For simple examples of how to call foreign code from Lean and vice versa, see <https://github.com/leanprover/lean4/blob/master/src/lake/examples/ffi> and <https://github.com/leanprover/lean4/blob/master/src/lake/examples/reverse-ffi>, respectively.
-
 ## The Lean ABI
 
 The Lean Application Binary Interface (ABI) describes how the signature of a Lean declaration is encoded as a native calling convention.
@@ -23,7 +21,7 @@ If `n` is 0, the corresponding C declaration is
 extern s sym;
 ```
 where `s` is the C translation of `β` as specified in the next section.
-In the case of an `@[extern]` definition, the symbol's value is guaranteed to be initialized only after calling the Lean module's initializer or that of an importing module; see [Initialization](#initialization).
+In the case of an `@[extern]` definition, the symbol's value is guaranteed to be initialized only after calling the Lean module's initializer or that of an importing module; see [Initialization](.#init).
 
 If `n` is greater than 0, the corresponding C declaration is
 ```c
@@ -34,7 +32,7 @@ In the case of `@[extern]` all *irrelevant* types are removed first; see next se
 
 ### Translating Types from Lean to C
 
-* The integer types `UInt8`, ..., `UInt64`, `USize` are represented by the C types `uint8_t`, ..., `uint64_t`, `size_t`, respectively
+* The integer types `UInt8`, ..., `UInt64`, `USize` are represented by the C types `uint8_t`, ..., `uint64_t`, `usize_t`, respectively
 * `Char` is represented by `uint32_t`
 * `Float` is represented by `double`
 * An *enum* inductive type of at least 2 and at most 2^32 constructors, each of which with no parameters, is represented by the first type of `uint8_t`, `uint16_t`, `uint32_t` that is sufficient to represent all constructor indices.
@@ -47,7 +45,7 @@ In the case of `@[extern]` all *irrelevant* types are removed first; see next se
   * it has a single constructor with a single parameter of *relevant* type
 
   is represented by the representation of that parameter's type.
-
+  
   For example, `{ x : α // p }`, the `Subtype` structure of a value of type `α` and an irrelevant proof, is represented by the representation of `α`.
 * `Nat` is represented by `lean_object *`.
   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`).
@@ -72,13 +70,13 @@ When including Lean code as part of a larger program, modules must be *initializ
 Module initialization entails
 * initialization of all "constants" (nullary functions), including closed terms lifted out of other functions
 * execution of all `[init]` functions
-* execution of all `[builtin_init]` functions, if the `builtin` parameter of the module initializer has been set
+* execution of all `[builtinInit]` functions, if the `builtin` parameter of the module initializer has been set
 
 The module initializer is automatically run with the `builtin` flag for executables compiled from Lean code and for "plugins" loaded with `lean --plugin`.
 For all other modules imported by `lean`, the initializer is run without `builtin`.
-Thus `[init]` functions are run iff their module is imported, regardless of whether they have native code available or not, while `[builtin_init]` functions are only run for native executable or plugins, regardless of whether their module is imported or not.
+Thus `[init]` functions are run iff their module is imported, regardless of whether they have native code available or not, while `[builtinInit]` functions are only run for native executable or plugins, regardless of whether their module is imported or not.
 `lean` uses built-in initializers for e.g. registering basic parsers that should be available even without importing their module (which is necessary for bootstrapping).
-
+  
 The initializer for module `A.B` is called `initialize_A_B` and will automatically initialize any imported modules.
 Module initializers are idempotent (when run with the same `builtin` flag), but not thread-safe.
 Together with initialization of the Lean runtime, you should execute code like the following exactly once before accessing any Lean declarations:
@@ -121,4 +119,4 @@ Thus to e.g. run `#eval` on such a declaration, you need to
 Note that it is not sufficient to load the foreign library containing the external symbol because the interpreter depends on code that is emitted for each `@[extern]` declaration.
 Thus it is not possible to interpret an `@[extern]` declaration in the same file.
 
-See [`tests/compiler/foreign`](https://github.com/leanprover/lean4/tree/master/tests/compiler/foreign/) for an example.
+See `tests/compiler/foreign` for an example.

doc/dev/index.md

@@ -1,6 +1,6 @@
 # Development Workflow
 
-If you want to make changes to Lean itself, start by [building Lean](../make/index.md) from a clean checkout to make sure that everything is set up correctly.
+If you want to make changes to Lean itself, start by [building Lean](../make/index.html) from a clean checkout to make sure that everything is set up correctly.
 After that, read on below to find out how to set up your editor for changing the Lean source code, followed by further sections of the development manual where applicable such as on the [test suite](testing.md) and [commit convention](commit_convention.md).
 
 If you are planning to make any changes that may affect the compilation of Lean itself, e.g. changes to the parser, elaborator, or compiler, you should first read about the [bootstrapping pipeline](bootstrap.md).
@@ -30,14 +30,20 @@ powershell -f elan-init.ps1 --default-toolchain none
 del elan-init.ps1
 ```
 
-The `lean-toolchain` files in the Lean 4 repository are set up to use the `lean4-stage0`
-toolchain for editing files in `src` and the `lean4` toolchain for editing files in `tests`.
-
-Run the following commands to make `lean4` point at `stage1` and `lean4-stage0` point at `stage0`:
+You can use `elan toolchain link` to give a specific stage build
+directory a reference name, then use `elan override set` to associate
+such a name to the current directory. We usually want to use `stage0`
+for editing files in `src` and `stage1` for everything else (e.g.
+tests).
 ```bash
 # in the Lean rootdir
 elan toolchain link lean4 build/release/stage1
 elan toolchain link lean4-stage0 build/release/stage0
+# make `lean` etc. point to stage1 in the rootdir and subdirs
+elan override set lean4
+cd src
+# make `lean` etc. point to stage0 anywhere inside `src`
+elan override set lean4-stage0
 ```
 
 You can also use the `+toolchain` shorthand (e.g. `lean +lean4-debug`) to switch
@@ -51,26 +57,3 @@ You might find that debugging through elan, e.g. via `gdb lean`, disables some
 things like symbol autocompletion because at first only the elan proxy binary
 is loaded. You can instead pass the explicit path to `bin/lean` in your build
 folder to gdb, or use `gdb $(elan which lean)`.
-
-It is also possible to generate releases that others can use,
-simply by pushing a tag to your fork of the Lean 4 github repository
-(and waiting about an hour; check the `Actions` tab for completion).
-If you push `my-tag` to a fork in your github account `my_name`,
-you can then put `my_name/lean4:my-tag` in your `lean-toolchain` file in a project using `lake`.
-(You must use a tag name that does not start with a numeral, or contain `_`).
-
-### VS Code
-
-There is a `lean.code-workspace` file that correctly sets up VS Code with workspace roots for the stage0/stage1 setup described above as well as with other settings.
-You should always load it when working on Lean, such as by invoking
-```
-code lean.code-workspace
-```
-on the command line.
-
-### `ccache`
-
-Lean's build process uses [`ccache`](https://ccache.dev/) if it is
-installed to speed up recompilation of the generated C code. Without
-`ccache`, you'll likely spend more time than necessary waiting on
-rebuilds - it's a good idea to make sure it's installed.

doc/dev/mdbook.md

@@ -1,7 +1,7 @@
 # Documentation
 
-The Lean `doc` folder contains the [Lean Manual](https://lean-lang.org/lean4/doc/) and is
-authored in a combination of markdown (`*.md`) files and literate Lean files.  The .lean files are
+The Lean `doc` folder contains the [Lean Manual](https://leanprover.github.io/lean4/doc/) and is
+authored in a combination of markdown (*.md) files and literate Lean files.  The .lean files are
 preprocessed using a tool called [LeanInk](https://github.com/leanprover/leanink) and
 [Alectryon](https://github.com/Kha/alectryon) which produces a generated markdown file.  We then run
 `mdbook` on the result to generate the html pages.
@@ -53,28 +53,25 @@ Then run the following:
     cargo install --git https://github.com/leanprover/mdBook mdbook
     ```
 
-1. Clone https://github.com/leanprover/LeanInk.git and run `lake build` then make the resulting
-   binary available to Alectryon using e.g.
-    ```bash
-    # make `leanInk` available in the current shell
-    export PATH=$PWD/build/bin:$PATH
-    ```
+1. Clone https://github.com/leanprover/LeanInk.git and run `lake build` then copy the resulting
+executable to your `$HOME/.elan/bin` folder or `%USERPROFILE%\.elan\bin` so Alectryon can find it
+there.
 
 1. Create a Python 3.10 environment.
 
-1. Install Alectryon:
+1. Install the following packages:
     ```
     python3 -m pip install git+https://github.com/Kha/alectryon.git@typeid
     ```
 
-1. Now you are ready to process the `*.lean` files using Alectryon as follows:
+1. Now you are ready to process the *.lean files using Alectryon as follows:
 
     ```
     cd lean4/doc
-    alectryon --frontend lean4+markup examples/palindromes.lean --backend webpage -o palindromes.lean.md
+    alectryon --frontend lean4+markup examples\palindromes.lean --backend webpage -o palindromes.lean.md
     ```
 
-    Repeat this for the other .lean files you care about or write a script to process them all.
+And repeat this for the other .lean files you care about or write a script to process them all.
 
 1. Now you can build the book using:
     ```
@@ -83,7 +80,7 @@ Then run the following:
     ```
 
 This will put the HTML in a `out` folder so you can load `out/index.html` in your web browser and
-it should look like https://lean-lang.org/lean4/doc/.
+it should look like https://leanprover.github.io/lean4/doc/.
 
 1. It is also handy to use e.g. [`mdbook watch`](https://rust-lang.github.io/mdBook/cli/watch.html)
    in the `doc/` folder so that it keeps the html up to date while you are editing.

doc/dev/testing.md

@@ -5,6 +5,7 @@ After [building Lean](../make/index.md) you can run all the tests using
 cd build/release
 make test ARGS=-j4
 ```
+
 Change the 4 to the maximum number of parallel tests you want to
 allow. The best choice is the number of CPU cores on your machine as
 the tests are mostly CPU bound.  You can find the number of processors
@@ -16,12 +17,6 @@ adding the `-C stageN` argument. The default when run as above is stage 1.  The
 Lean tests will automatically use that stage's corresponding Lean
 executables
 
-Running `make test` will not pick up new test files; run
-```bash
-cmake build/release/stage1
-```
-to update the list of tests.
-
 You can also use `ctest` directly if you are in the right folder.  So
 to run stage1 tests with a 300 second timeout run this:
 
@@ -29,9 +24,6 @@ to run stage1 tests with a 300 second timeout run this:
 cd build/release/stage1
 ctest -j 4 --output-on-failure --timeout 300
 ```
-Useful `ctest` flags are `-R <name of test>` to run a single test, and
-`--rerun-failed` to run all tests that failed during the last run.
-You can also pass `ctest` flags via `make test ARGS="--rerun-failed"`.
 
 To get verbose output from ctest pass the `--verbose` command line
 option. Test output is normally suppressed and only summary
@@ -41,17 +33,17 @@ information is displayed. This option will show all test output.
 
 All these tests are included by [src/shell/CMakeLists.txt](https://github.com/leanprover/lean4/blob/master/src/shell/CMakeLists.txt):
 
-- [`tests/lean`](https://github.com/leanprover/lean4/tree/master/tests/lean/): contains tests that come equipped with a
-  .lean.expected.out file. The driver script [`test_single.sh`](https://github.com/leanprover/lean4/tree/master/tests/lean/test_single.sh) runs
+- `tests/lean`: contains tests that come equipped with a
+  .lean.expected.out file. The driver script `test_single.sh` runs
   each test and checks the actual output (*.produced.out) with the
   checked in expected output.
 
-- [`tests/lean/run`](https://github.com/leanprover/lean4/tree/master/tests/lean/run/): contains tests that are run through the lean
+- `tests/lean/run`: contains tests that are run through the lean
   command line one file at a time. These tests only look for error
   codes and do not check the expected output even though output is
   produced, it is ignored.
 
-- [`tests/lean/interactive`](https://github.com/leanprover/lean4/tree/master/tests/lean/interactive/): are designed to test server requests at a
+- `tests/lean/interactive`: are designed to test server requests at a
   given position in the input file. Each .lean file contains comments
   that indicate how to simulate a client request at that position.
   using a `--^` point to the line position. Example:
@@ -61,7 +53,7 @@ All these tests are included by [src/shell/CMakeLists.txt](https://github.com/le
     Bla.
       --^ textDocument/completion
     ```
-    In this example, the test driver [`test_single.sh`](https://github.com/leanprover/lean4/tree/master/tests/lean/interactive/test_single.sh) will simulate an
+    In this example, the test driver `test_single.sh` will simulate an
     auto-completion request at `Bla.`. The expected output is stored in
     a .lean.expected.out in the json format that is part of the
     [Language Server
@@ -78,33 +70,23 @@ All these tests are included by [src/shell/CMakeLists.txt](https://github.com/le
     --^ collectDiagnostics
     ```
 
-- [`tests/lean/server`](https://github.com/leanprover/lean4/tree/master/tests/lean/server/): Tests more of the Lean `--server` protocol.
+- `tests/lean/server`: Tests more of the Lean `--server` protocol.
   There are just a few of them, and it uses .log files containing
   JSON.
 
-- [`tests/compiler`](https://github.com/leanprover/lean4/tree/master/tests/compiler/): contains tests that will run the Lean compiler and
+- `tests/compiler`: contains tests that will run the Lean compiler and
   build an executable that is executed and the output is compared to
   the .lean.expected.out file. This test also contains a subfolder
-  [`foreign`](https://github.com/leanprover/lean4/tree/master/tests/compiler/foreign/) which shows how to extend Lean using C++.
+  `foreign` which shows how to extend Lean using C++.
 
-- [`tests/lean/trust0`](https://github.com/leanprover/lean4/tree/master/tests/lean/trust0): tests that run Lean in a mode that Lean doesn't
+- `tests/lean/trust0`: tests that run Lean in a mode that Lean doesn't
   even trust the .olean files (i.e., trust 0).
 
-- [`tests/bench`](https://github.com/leanprover/lean4/tree/master/tests/bench/): contains performance tests.
+- `tests/bench`: contains performance tests.
 
-- [`tests/plugin`](https://github.com/leanprover/lean4/tree/master/tests/plugin/): tests that compiled Lean code can be loaded into
+- `tests/plugin`: tests that compiled Lean code can be loaded into
   `lean` via the `--plugin` command line option.
 
-## Writing Good Tests
-
-Every test file should contain:
-* an initial `/-! -/` module docstring summarizing the test's purpose
-* a module docstring for each test section that describes what is tested
-  and, if not 100% clear, why that is the desirable behavior
-
-At the time of writing, most tests do not follow these new guidelines yet.
-For an example of a conforming test, see [`tests/lean/1971.lean`](https://github.com/leanprover/lean4/tree/master/tests/lean/1971.lean).
-
 ## Fixing Tests
 
 When the Lean source code or the standard library are modified, some of the
@@ -119,7 +101,7 @@ First, we must install [meld](http://meldmerge.org/). On Ubuntu, we can do it by
 sudo apt-get install meld
 ```
 
-Now, suppose `bad_class.lean` test is broken. We can see the problem by going to [`tests/lean`](https://github.com/leanprover/lean4/tree/master/tests/lean) directory and
+Now, suppose `bad_class.lean` test is broken. We can see the problem by going to `test/lean` directory and
 executing
 
 ```
@@ -132,3 +114,8 @@ outputs. `meld` can also be used to repair the problems.
 
 In Emacs, we can also execute `M-x lean4-diff-test-file` to check/diff the file of the current buffer.
 To mass-copy all `.produced.out` files to the respective `.expected.out` file, use `tests/lean/copy-produced`.
+When using the Nix setup, add `--keep-failed` to the `nix build` call and then call
+```sh
+tests/lean/copy-produced <build-dir>/source/tests/lean
+```
+instead where `<build-dir>` is the path printed out by `nix build`.

doc/examples/Certora2022/ex1.lean

@@ -1,22 +0,0 @@
-/- "Hello world" -/
-
-#eval "hello" ++ " " ++ "world"
--- "hello world"
-
-#check true
--- Bool
-
-def x := 10
-
-#eval x + 2
--- 12
-
-def double (x : Int) := 2*x
-
-#eval double 3
--- 6
-#check double
--- Int → Int
-example : double 4 = 8 := rfl
-
-

doc/examples/Certora2022/ex10.lean

@@ -1,19 +0,0 @@
-/- Dependent pattern matching -/
-
-inductive Vector (α : Type u) : Nat → Type u
-  | nil : Vector α 0
-  | cons : α → Vector α n → Vector α (n+1)
-
-infix:67 "::" => Vector.cons
-
-def Vector.zip : Vector α n → Vector β n → Vector (α × β) n
-  | nil, nil => nil
-  | a::as, b::bs => (a, b) :: zip as bs
-
-#print Vector.zip
-/-
-def Vector.zip.{u_1, u_2} : {α : Type u_1} → {n : Nat} → {β : Type u_2} → Vector α n → Vector β n → Vector (α × β) n :=
-fun {α} {n} {β} x x_1 =>
-  Vector.brecOn (motive := fun {n} x => {β : Type u_2} → Vector β n → Vector (α × β) n) x
-    ...
--/

doc/examples/Certora2022/ex11.lean

@@ -1,22 +0,0 @@
-/- Structures -/
-
-structure Point where
-  x : Int := 0
-  y : Int := 0
-  deriving Repr
-
-#eval Point.x (Point.mk 10 20)
--- 10
-
-#eval { x := 10, y := 20 : Point }
-
-def p : Point := { y := 20 }
-
-#eval p.x
-#eval p.y
-#eval { p with x := 5 }
--- { x := 5, y := 20 }
-
-structure Point3D extends Point where
-  z : Int
-

doc/examples/Certora2022/ex12.lean

@@ -1,28 +0,0 @@
-/- Type classes -/
-namespace Example
-
-class ToString (α : Type u) where
-  toString : α → String
-
-#check @ToString.toString
--- {α : Type u_1} → [self : ToString α] → α → String
-
-instance : ToString String where
-  toString s := s
-
-instance : ToString Bool where
-  toString b := if b then "true" else "false"
-
-#eval ToString.toString "hello"
-export ToString (toString)
-#eval toString true
--- "true"
--- #eval toString (true, "hello") -- Error
-
-instance [ToString α] [ToString β] : ToString (α × β) where
-  toString p := "(" ++ toString p.1 ++ ", " ++ toString p.2 ++ ")"
-
-#eval toString (true, "hello")
--- "(true, hello)"
-
-end Example

doc/examples/Certora2022/ex13.lean

@@ -1,44 +0,0 @@
-/- Type classes are heavily used in Lean -/
-namespace Example
-
-class Mul (α : Type u) where
-  mul : α → α → α
-
-infixl:70 " * " => Mul.mul
-
-def double [Mul α] (a : α) := a * a
-
-class Semigroup (α : Type u) extends Mul α where
-  mul_assoc : ∀ a b c : α, (a * b) * c = a * (b * c)
-
-instance : Semigroup Nat where
-  mul := Nat.mul
-  mul_assoc := Nat.mul_assoc
-
-#eval double 5
-
-class Functor (f : Type u → Type v) : Type (max (u+1) v) where
-  map : (α → β) → f α → f β
-
-infixr:100 " <$> " => Functor.map
-
-class LawfulFunctor (f : Type u → Type v) [Functor f] : Prop where
-  id_map   (x : f α) : id <$> x = x
-  comp_map (g : α → β) (h : β → γ) (x : f α) :(h ∘ g) <$> x = h <$> g <$> x
-
-end Example
-
-/-
-`Deriving instances automatically`
-
-We have seen `deriving Repr` in a few examples.
-It is an instance generator.
-Lean comes equipped with generators for the following classes.
-`Repr`, `Inhabited`, `BEq`, `DecidableEq`,
-`Hashable`, `Ord`, `FromToJson`, `SizeOf`
--/
-
-inductive Tree (α : Type u) where
-  | leaf (val : α)
-  | node (left right : Tree α)
-  deriving DecidableEq, Ord, Inhabited, Repr

doc/examples/Certora2022/ex14.lean

@@ -1,31 +0,0 @@
-/- Tactics -/
-
-example : p → q → p ∧ q ∧ p := by
-  intro hp hq
-  apply And.intro
-  exact hp
-  apply And.intro
-  exact hq
-  exact hp
-
-example : p → q → p ∧ q ∧ p := by
-  intro hp hq; apply And.intro hp; exact And.intro hq hp
-
-/- Structuring proofs -/
-
-example : p → q → p ∧ q ∧ p := by
-  intro hp hq
-  apply And.intro
-  case left => exact hp
-  case right =>
-    apply And.intro
-    case left => exact hq
-    case right => exact hp
-
-example : p → q → p ∧ q ∧ p := by
-  intro hp hq
-  apply And.intro
-  . exact hp
-  . apply And.intro
-    . exact hq
-    . exact hp

doc/examples/Certora2022/ex15.lean

@@ -1,19 +0,0 @@
-/- intro tactic variants -/
-
-example (p q : α → Prop) : (∃ x, p x ∧ q x) → ∃ x, q x ∧ p x := by
-  intro h
-  match h with
-  | Exists.intro w (And.intro hp hq) => exact Exists.intro w (And.intro hq hp)
-
-example (p q : α → Prop) : (∃ x, p x ∧ q x) → ∃ x, q x ∧ p x := by
-  intro (Exists.intro _ (And.intro hp hq))
-  exact Exists.intro _ (And.intro hq hp)
-
-example (p q : α → Prop) : (∃ x, p x ∧ q x) → ∃ x, q x ∧ p x := by
-  intro ⟨_, hp, hq⟩
-  exact ⟨_, hq, hp⟩
-
-example (α : Type) (p q : α → Prop) : (∃ x, p x ∨ q x) → ∃ x, q x ∨ p x := by
-  intro
-    | ⟨_, .inl h⟩ => exact ⟨_, .inr h⟩
-    | ⟨_, .inr h⟩ => exact ⟨_, .inl h⟩

doc/examples/Certora2022/ex16.lean

@@ -1,12 +0,0 @@
-/- Inaccessible names -/
-
-example : ∀ x y : Nat, x = y → y = x := by
-  intros
-  apply Eq.symm
-  assumption
-
-example : ∀ x y : Nat, x = y → y = x := by
-  intros
-  apply Eq.symm
-  rename_i a b hab
-  exact hab

doc/examples/Certora2022/ex17.lean

@@ -1,19 +0,0 @@
-/- More tactics -/
-
-example (p q : Nat → Prop) : (∃ x, p x ∧ q x) → ∃ x, q x ∧ p x := by
-  intro h
-  cases h with
-  | intro x hpq =>
-    cases hpq with
-    | intro hp hq =>
-      exists x
-
-example : p ∧ q → q ∧ p := by
-  intro p
-  cases p
-  constructor <;> assumption
-
-example : p ∧ ¬ p → q := by
-  intro h
-  cases h
-  contradiction

doc/examples/Certora2022/ex18.lean

@@ -1,20 +0,0 @@
-/- Structuring proofs (cont.) -/
-
-example : p ∧ (q ∨ r) → (p ∧ q) ∨ (p ∧ r) := by
-  intro h
-  have hp : p := h.left
-  have hqr : q ∨ r := h.right
-  show (p ∧ q) ∨ (p ∧ r)
-  cases hqr with
-  | inl hq => exact Or.inl ⟨hp, hq⟩
-  | inr hr => exact Or.inr ⟨hp, hr⟩
-
-example : p ∧ (q ∨ r) → (p ∧ q) ∨ (p ∧ r) := by
-  intro ⟨hp, hqr⟩
-  cases hqr with
-  | inl hq =>
-    have := And.intro hp hq
-    apply Or.inl; exact this
-  | inr hr =>
-    have := And.intro hp hr
-    apply Or.inr; exact this

doc/examples/Certora2022/ex19.lean

@@ -1,10 +0,0 @@
-/- Tactic combinators -/
-
-example : p → q → r → p ∧ ((p ∧ q) ∧ r) ∧ (q ∧ r ∧ p) := by
-  intros
-  repeat (any_goals constructor)
-  all_goals assumption
-
-example : p → q → r → p ∧ ((p ∧ q) ∧ r) ∧ (q ∧ r ∧ p) := by
-  intros
-  repeat (any_goals (first | assumption | constructor))

doc/examples/Certora2022/ex2.lean

@@ -1,14 +0,0 @@
-/- First-class functions -/
-
-def twice (f : Nat → Nat) (a : Nat) :=
-  f (f a)
-
-#check twice
--- (Nat → Nat) → Nat → Nat
-
-#eval twice (fun x => x + 2) 10
-
-theorem twice_add_2 (a : Nat) : twice (fun x => x + 2) a = a + 4 := rfl
-
--- `(· + 2)` is syntax sugar for `(fun x => x + 2)`.
-#eval twice (· + 2) 10

doc/examples/Certora2022/ex20.lean

@@ -1,22 +0,0 @@
-/- Rewriting -/
-
-example (f : Nat → Nat) (k : Nat) (h₁ : f 0 = 0) (h₂ : k = 0) : f k = 0 := by
-  rw [h₂] -- replace k with 0
-  rw [h₁] -- replace f 0 with 0
-
-example (f : Nat → Nat) (k : Nat) (h₁ : f 0 = 0) (h₂ : k = 0) : f k = 0 := by
-  rw [h₂, h₁]
-
-example (f : Nat → Nat) (a b : Nat) (h₁ : a = b) (h₂ : f a = 0) : f b = 0 := by
-  rw [← h₁, h₂]
-
-example (f : Nat → Nat) (a : Nat) (h : 0 + a = 0) : f a = f 0 := by
-  rw [Nat.zero_add] at h
-  rw [h]
-
-def Tuple (α : Type) (n : Nat) :=
-  { as : List α // as.length = n }
-
-example (n : Nat) (h : n = 0) (t : Tuple α n) : Tuple α 0 := by
-  rw [h] at t
-  exact t

doc/examples/Certora2022/ex21.lean

@@ -1,21 +0,0 @@
-/- Simplifier -/
-
-example (p : Nat → Prop) : (x + 0) * (0 + y * 1 + z * 0) = x * y := by
-  simp
-
-example (p : Nat → Prop) (h : p (x * y)) : p ((x + 0) * (0 + y * 1 + z * 0)) := by
-  simp; assumption
-
-example (p : Nat → Prop) (h : p ((x + 0) * (0 + y * 1 + z * 0))) : p (x * y) := by
-  simp at h; assumption
-
-def f (m n : Nat) : Nat :=
-  m + n + m
-
-example (h : n = 1) (h' : 0 = m) : (f m n) = n := by
-  simp [h, ←h', f]
-
-example (p : Nat → Prop) (h₁ : x + 0 = x') (h₂ : y + 0 = y')
-        : x + y + 0 = x' + y' := by
-  simp at *
-  simp [*]

doc/examples/Certora2022/ex22.lean

@@ -1,13 +0,0 @@
-/- Simplifier -/
-
-def mk_symm (xs : List α) :=
-  xs ++ xs.reverse
-
-@[simp] theorem reverse_mk_symm : (mk_symm xs).reverse = mk_symm xs := by
-  simp [mk_symm]
-
-theorem tst : (xs ++ mk_symm ys).reverse = mk_symm ys ++ xs.reverse := by
-  simp
-
-#print tst
--- Lean reverse_mk_symm, and List.reverse_append

doc/examples/Certora2022/ex23.lean

@@ -1,26 +0,0 @@
-/- split tactic -/
-
-def f (x y z : Nat) : Nat :=
-  match x, y, z with
-  | 5, _, _ => y
-  | _, 5, _ => y
-  | _, _, 5 => y
-  | _, _, _ => 1
-
-example : x ≠ 5 → y ≠ 5 → z ≠ 5 → z = w → f x y w = 1 := by
-  intros
-  simp [f]
-  split
-  . contradiction
-  . contradiction
-  . contradiction
-  . rfl
-
-def g (xs ys : List Nat) : Nat :=
-  match xs, ys with
-  | [a, b], _ => a+b+1
-  | _, [b, c] => b+1
-  | _, _      => 1
-
-example (xs ys : List Nat) (h : g xs ys = 0) : False := by
-  unfold g at h; split at h <;> simp_arith at h

doc/examples/Certora2022/ex24.lean

@@ -1,9 +0,0 @@
-/- induction tactic -/
-
-example (as : List α) (a : α) : (as.concat a).length = as.length + 1 := by
-  induction as with
-  | nil => rfl
-  | cons _ xs ih => simp [List.concat, ih]
-
-example (as : List α) (a : α) : (as.concat a).length = as.length + 1 := by
-  induction as <;> simp! [*]

doc/examples/Certora2022/ex3.lean

@@ -1,59 +0,0 @@
-/- Enumerated types -/
-
-inductive Weekday where
-  | sunday | monday | tuesday | wednesday
-  | thursday | friday | saturday
-
-#check Weekday.sunday
--- Weekday
-
-open Weekday
-#check sunday
-
-def natOfWeekday (d : Weekday) : Nat :=
-  match d with
-  | sunday    => 1
-  | monday    => 2
-  | tuesday   => 3
-  | wednesday => 4
-  | thursday  => 5
-  | friday    => 6
-  | saturday  => 7
-
-def Weekday.next (d : Weekday) : Weekday :=
-  match d with
-  | sunday    => monday
-  | monday    => tuesday
-  | tuesday   => wednesday
-  | wednesday => thursday
-  | thursday  => friday
-  | friday    => saturday
-  | saturday  => sunday
-
-def Weekday.previous : Weekday → Weekday
-  | sunday    => saturday
-  | monday    => sunday
-  | tuesday   => monday
-  | wednesday => tuesday
-  | thursday  => wednesday
-  | friday    => thursday
-  | saturday  => friday
-
-/- Proving theorems using tactics -/
-
-theorem Weekday.next_previous (d : Weekday) : d.next.previous = d :=
-  match d with
-  | sunday    => rfl
-  | monday    => rfl
-  | tuesday   => rfl
-  | wednesday => rfl
-  | thursday  => rfl
-  | friday    => rfl
-  | saturday  => rfl
-
-theorem Weekday.next_previous' (d : Weekday) : d.next.previous = d := by -- switch to tactic mode
-  cases d -- Creates 7 goals
-  rfl; rfl; rfl; rfl; rfl; rfl; rfl
-
-theorem Weekday.next_previous'' (d : Weekday) : d.next.previous = d := by
-  cases d <;> rfl

doc/examples/Certora2022/ex4.lean

@@ -1,20 +0,0 @@
-/- What is the type of Nat? -/
-
-#check 0
--- Nat
-#check Nat
--- Type
-#check Type
--- Type 1
-#check Type 1
--- Type 2
-#check Eq.refl 2
--- 2 = 2
-#check 2 = 2
--- Prop
-#check Prop
--- Type
-
-example : Prop = Sort 0   := rfl
-example : Type = Sort 1   := rfl
-example : Type 1 = Sort 2 := rfl

doc/examples/Certora2022/ex5.lean

@@ -1,21 +0,0 @@
-/- Implicit arguments and universe polymorphism -/
-
-def f (α β : Sort u) (a : α) (b : β) : α := a
-
-#eval f Nat String 1 "hello"
--- 1
-
-def g {α β : Sort u} (a : α) (b : β) : α := a
-
-#eval g 1 "hello"
-
-def h (a : α) (b : β) : α := a
-
-#check g
--- ?m.1 → ?m.2 → ?m.1
-#check @g
--- {α β : Sort u} → α → β → α
-#check @h
--- {α : Sort u_1} → {β : Sort u_2} → α → β → α
-#check g (α := Nat) (β := String)
--- Nat → String → Nat

doc/examples/Certora2022/ex6.lean

@@ -1,14 +0,0 @@
-/- Inductive Types -/
-
-inductive Tree (β : Type v) where
-  | leaf
-  | node (left : Tree β) (key : Nat) (value : β) (right : Tree β)
-  deriving Repr
-
-#eval Tree.node .leaf 10 true .leaf
--- Tree.node Tree.leaf 10 true Tree.leaf
-
-inductive Vector (α : Type u) : Nat → Type u
-  | nil : Vector α 0
-  | cons : α → Vector α n → Vector α (n+1)
-

doc/examples/Certora2022/ex7.lean

@@ -1,25 +0,0 @@
-/- Recursive functions -/
-
-#print Nat -- Nat is an inductive datatype
-
-def fib (n : Nat) : Nat :=
-  match n with
-  | 0 => 1
-  | 1 => 1
-  | n+2 => fib (n+1) + fib n
-
-example : fib 5 = 8 := rfl
-
-example : fib (n+2) = fib (n+1) + fib n := rfl
-
-#print fib
-/-
-def fib : Nat → Nat :=
-fun n =>
-  Nat.brecOn n fun n f =>
-    (match (motive := (n : Nat) → Nat.below n → Nat) n with
-      | 0 => fun x => 1
-      | 1 => fun x => 1
-      | Nat.succ (Nat.succ n) => fun x => x.fst.fst + x.fst.snd.fst.fst)
-      f
--/

doc/examples/Certora2022/ex8.lean

@@ -1,25 +0,0 @@
-/- Well-founded recursion -/
-
-def ack : Nat → Nat → Nat
-  | 0,   y   => y+1
-  | x+1, 0   => ack x 1
-  | x+1, y+1 => ack x (ack (x+1) y)
-termination_by ack x y => (x, y)
-
-def sum (a : Array Int) : Int :=
-  let rec go (i : Nat) :=
-     if i < a.size then
-        a[i] + go (i+1)
-     else
-        0
-  go 0
-termination_by go i => a.size - i
-
-set_option pp.proofs true
-#print sum.go
-/-
-def sum.go : Array Int → Nat → Int :=
-fun a =>
-  WellFounded.fix (sum.go.proof_1 a) fun i a_1 =>
-    if h : i < Array.size a then Array.getOp a i + a_1 (i + 1) (sum.go.proof_2 a i h) else 0
--/

doc/examples/Certora2022/ex9.lean

@@ -1,44 +0,0 @@
-/- Mutual recursion -/
-
-inductive Term where
- | const : String → Term
- | app   : String → List Term → Term
-
-namespace Term
-mutual
- def numConsts : Term → Nat
-   | const _ => 1
-   | app _ cs => numConstsLst cs
-
- def numConstsLst : List Term → Nat
-   | [] => 0
-   | c :: cs => numConsts c + numConstsLst cs
-end
-
-mutual
-  def replaceConst (a b : String) : Term → Term
-   | const c => if a = c then const b else const c
-   | app f cs => app f (replaceConstLst a b cs)
-
-  def replaceConstLst (a b : String) : List Term → List Term
-   | [] => []
-   | c :: cs => replaceConst a b c :: replaceConstLst a b cs
-end
-
-/- Mutual recursion in theorems -/
-
-mutual
-  theorem numConsts_replaceConst (a b : String) (e : Term)
-            : numConsts (replaceConst a b e) = numConsts e := by
-    match e with
-    | const c => simp [replaceConst]; split <;> simp [numConsts]
-    | app f cs => simp [replaceConst, numConsts, numConsts_replaceConstLst a b cs]
-
-  theorem numConsts_replaceConstLst (a b : String) (es : List Term)
-            : numConstsLst (replaceConstLst a b es) = numConstsLst es := by
-    match es with
-    | [] => simp [replaceConstLst, numConstsLst]
-    | c :: cs =>
-      simp [replaceConstLst, numConstsLst, numConsts_replaceConst a b c,
-            numConsts_replaceConstLst a b cs]
-end

doc/examples/bintree.lean

@@ -5,7 +5,7 @@ If the type of keys can be totally ordered -- that is, it supports a well-behave
 then maps can be implemented with binary search trees (BSTs). Insert and lookup operations on BSTs take time
 proportional to the height of the tree. If the tree is balanced, the operations therefore take logarithmic time.
 
-This example is based on a similar example found in the ["Software Foundations"](https://softwarefoundations.cis.upenn.edu/vfa-current/SearchTree.html)
+This example is based on a similar example found in the ["Sofware Foundations"](https://softwarefoundations.cis.upenn.edu/vfa-current/SearchTree.html)
 book (volume 3).
 -/
 
@@ -81,9 +81,9 @@ def Tree.toList (t : Tree β) : List (Nat × β) :=
       |>.toList
 
 /-!
-The implementation of `Tree.toList` is inefficient because of how it uses the `++` operator.
+The implemention of `Tree.toList` is inefficient because of how it uses the `++` operator.
 On a balanced tree its running time is linearithmic, because it does a linear number of
-concatenations at each level of the tree. On an unbalanced tree it's quadratic time.
+concatentations at each level of the tree. On an unbalanced tree it's quadratic time.
 Here's a tail-recursive implementation than runs in linear time, regardless of whether the tree is balanced:
 -/
 def Tree.toListTR (t : Tree β) : List (Nat × β) :=
@@ -114,9 +114,9 @@ concatenating all goals produced by `tac'`. In this theorem, we use it to apply
 
 The `simp` parameters `toListTR.go` and `toList` instruct the simplifier to try to reduce
 and/or apply auto generated equation theorems for these two functions.
-The parameter `*` instructs the simplifier to use any equation in a goal as rewriting rules.
+The parameter `*` intructs the simplifier to use any equation in a goal as rewriting rules.
 In this particular case, `simp` uses the induction hypotheses as rewriting rules.
-Finally, the parameter `List.append_assoc` instructs the simplifier to use the
+Finally, the parameter `List.append_assoc` intructs the simplifier to use the
 `List.append_assoc` theorem as a rewriting rule.
 -/
 theorem Tree.toList_eq_toListTR (t : Tree β)
@@ -176,8 +176,7 @@ The modifier `local` specifies the scope of the macro.
 /-- The `have_eq lhs rhs` tactic (tries to) prove that `lhs = rhs`,
     and then replaces `lhs` with `rhs`. -/
 local macro "have_eq " lhs:term:max rhs:term:max : tactic =>
-  `(tactic|
-    (have h : $lhs = $rhs :=
+  `((have h : $lhs = $rhs :=
        -- TODO: replace with linarith
        by simp_arith at *; apply Nat.le_antisymm <;> assumption
      try subst $lhs))
@@ -186,13 +185,13 @@ local macro "have_eq " lhs:term:max rhs:term:max : tactic =>
 The `by_cases' e` is just the regular `by_cases` followed by `simp` using all
 hypotheses in the current goal as rewriting rules.
 Recall that the `by_cases` tactic creates two goals. One where we have `h : e` and
-another one containing `h : ¬ e`. The simplifier uses the `h` to rewrite `e` to `True`
+another one containing `h : ¬ e`. The simplier uses the `h` to rewrite `e` to `True`
 in the first subgoal, and `e` to `False` in the second. This is particularly
 useful if `e` is the condition of an `if`-statement.
 -/
 /-- `by_cases' e` is a shorthand form `by_cases e <;> simp[*]` -/
 local macro "by_cases' " e:term :  tactic =>
-  `(tactic| by_cases $e <;> simp [*])
+  `(by_cases $e <;> simp [*])
 
 
 /-!
@@ -282,7 +281,7 @@ theorem BinTree.find_insert_of_ne (b : BinTree β) (h : k ≠ k') (v : β)
   let ⟨t, h⟩ := b; simp
   induction t with simp
   | leaf =>
-    split <;> (try simp) <;> split <;> (try simp)
+    split <;> simp <;> split <;> simp
     have_eq k k'
     contradiction
   | node left key value right ihl ihr =>

doc/examples/deBruijn.lean

@@ -152,7 +152,7 @@ We prove all cases but the one for `plus` using `simp [*]`. This tactic instruct
 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
+The modifier `←` in a term simplifier argument instructs the term simplier to use the equation as a rewriting rule in
 the "reverse direction". That is, given `h : a = b`, `← h` instructs the term simplifier to rewrite `b` subterms to `a`.
 -/
 theorem Term.constFold_sound (e : Term ctx ty) : e.constFold.denote env = e.denote env := by

doc/examples/interp.lean

@@ -83,7 +83,7 @@ In practice, this means we use `stop` to refer to the most recently defined vari
 
 A value `Expr.val` carries a concrete representation of an integer.
 
-A lambda `Expr.lam` creates a function. In the scope of a function of type `Ty.fn a ty`, there is a
+A lambda `Expr.lam` creates a function. In the scope of a function ot type `Ty.fn a ty`, there is a
 new local variable of type `a`.
 
 A function application `Expr.app` produces a value of type `ty` given a function from `a` to `ty` and a value of type `a`.
@@ -139,7 +139,7 @@ def add : Expr ctx (Ty.fn Ty.int (Ty.fn Ty.int Ty.int)) :=
 More interestingly, a factorial function fact (e.g. `fun x => if (x == 0) then 1 else (fact (x-1) * x)`), can be written as.
 Note that this is a recursive (non-terminating) definition. For every input value, the interpreter terminates, but the
 definition itself is non-terminating. We use two tricks to make sure Lean accepts it. First, we use the auxiliary constructor
-`Expr.delay` to delay its unfolding. Second, we add the annotation `decreasing_by sorry` which can be viewed as
+`Expr.delay` to delay its unfolding. Second, we add the annotation `decreasing_by sorry` which can be viwed as
 "trust me, this recursive definition makes sense". Recall that `sorry` is an unsound axiom in Lean.
 -/
 

doc/examples/palindromes.lean

@@ -82,7 +82,7 @@ theorem List.palindrome_ind (motive : List α → Prop)
     have ih := palindrome_ind motive h₁ h₂ h₃ (a₂::as').dropLast
     have : [a₁] ++ (a₂::as').dropLast ++ [(a₂::as').last (by simp)] = a₁::a₂::as' := by simp
     this ▸ h₃ _ _ _ ih
-termination_by as.length
+termination_by _ as => as.length
 
 /-!
 We use our new induction principle to prove that if `as.reverse = as`, then `Palindrome as` holds.

doc/examples/phoas.lean

@@ -228,7 +228,7 @@ We prove all cases but the one for `plus` using `simp [*]`. This tactic instruct
 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
+The modifier `←` in a term simplifier argument instructs the term simplier to use the equation as a rewriting rule in
 the "reverse direction. That is, given `h : a = b`, `← h` instructs the term simplifier to rewrite `b` subterms to `a`.
 -/
 theorem constFold_sound (e : Term' Ty.denote ty) : denote (constFold e) = denote e := by

doc/examples/tc.lean

@@ -38,7 +38,7 @@ theorem HasType.det (h₁ : HasType e t₁) (h₂ : HasType e t₂) : t₁ = t
   cases h₁ <;> cases h₂ <;> rfl
 
 /-!
-The inductive type `Maybe p` has two constructors: `found a h` and `unknown`.
+The inductive type `Maybe p` has two contructors: `found a h` and `unknown`.
 The former contains an element `a : α` and a proof that `a` satisfies the predicate `p`.
 The constructor `unknown` is used to encode "failure".
 -/

doc/examples/widgets.lean

@@ -15,8 +15,9 @@ sections of a Lean document. User widgets are rendered in the Lean infoview.
 To try it out, simply type in the following code and place your cursor over the `#widget` command.
 -/
 
-@[widget_module]
-def helloWidget : Widget.Module where
+@[widget]
+def helloWidget : UserWidgetDefinition where
+  name := "Hello"
   javascript := "
     import * as React from 'react';
     export default function(props) {
@@ -24,7 +25,7 @@ def helloWidget : Widget.Module where
       return React.createElement('p', {}, name + '!')
     }"
 
-#widget helloWidget
+#widget helloWidget .null
 
 /-!
 If you want to dive into a full sample right away, check out
@@ -55,11 +56,7 @@ to the React component. In our first invocation of `#widget`, we set it to `.nul
 happens when you type in:
 -/
 
-structure HelloWidgetProps where
-  name? : Option String := none
-  deriving Server.RpcEncodable
-
-#widget helloWidget with { name? := "<your name here>" : HelloWidgetProps }
+#widget helloWidget (Json.mkObj [("name", "<your name here>")])
 
 /-!
 💡 NOTE: The RPC system presented below does not depend on JavaScript. However the primary use case
@@ -109,13 +106,13 @@ more information for us, in the form of a `snap : Snapshot`. With this in hand,
 -/
 
 open Server RequestM in
-@[server_rpc_method]
+@[serverRpcMethod]
 def getType (params : GetTypeParams) : RequestM (RequestTask CodeWithInfos) :=
   withWaitFindSnapAtPos params.pos fun snap => do
     runTermElabM snap do
       let name ← resolveGlobalConstNoOverloadCore params.name
-      let c ← try getConstInfo name
-        catch _ => throwThe RequestError ⟨.invalidParams, s!"no constant named '{name}'"⟩
+      let some c ← Meta.getConst? name
+        | throwThe RequestError ⟨.invalidParams, s!"no constant named '{name}'"⟩
       Widget.ppExprTagged c.type
 
 /-!
@@ -129,14 +126,14 @@ as seen in the goal view. We will use it to implement our custom `#check` displa
 ⚠️ 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 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.
+The `useAsync` helper packs the results of a call into a `status` enum, the returned `val`ue in case
+the call was successful, and otherwise an `err`or. Based on the `status` we either display
+an `InteractiveCode`, or `mapRpcError` the error in order to turn it into a readable message.
 -/
 
-@[widget_module]
-def checkWidget : Widget.Module where
+@[widget]
+def checkWidget : UserWidgetDefinition where
+  name := "#check as a service"
   javascript := "
 import * as React from 'react';
 const e = React.createElement;
@@ -146,15 +143,18 @@ export default function(props) {
   const rs = React.useContext(RpcContext)
   const [name, setName] = React.useState('getType')
 
-  const st = useAsync(() =>
+  const [status, val, err] = useAsync(() =>
     rs.call('getType', { name, pos: props.pos }), [name, rs, props.pos])
 
-  const type = st.state === 'resolved' ? st.value && e(InteractiveCode, {fmt: st.value})
-    : st.state === 'rejected' ? e('p', null, mapRpcError(st.error).message)
-    : e('p', null, 'Loading..')
+  const type = status === 'fulfilled' ? val && e(InteractiveCode, {fmt: val})
+    : status === 'rejected' ? e('p', null, mapRpcError(err).message)
+      : e('p', null, 'Loading..')
+
   const onChange = (event) => { setName(event.target.value) }
   return e('div', null,
-    e('input', { value: name, onChange }), ' : ', type)
+    e('input', { value: name, onChange }),
+    ' : ',
+    type)
 }
 "
 
@@ -162,7 +162,7 @@ export default function(props) {
 Finally we can try out the widget.
 -/
 
-#widget checkWidget
+#widget checkWidget .null
 
 /-!
 ![`#check` as a service](../images/widgets_caas.png)
@@ -183,35 +183,4 @@ the infoview we need to:
 
 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
-
-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.
-
-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]
-def insertTextWidget : Widget.Module where
-  javascript := "
-import * as React from 'react';
-const e = React.createElement;
-import { EditorContext } from '@leanprover/infoview';
-
-export default function(props) {
-  const editorConnection = React.useContext(EditorContext)
-  function onClick() {
-    editorConnection.api.insertText('-- hello!!!', 'above')
-  }
-
-  return e('div', null, e('button', { value: name, onClick }, 'insert'))
-}
-"
-
-/-! Finally, we can try this out: -/
-
-#widget insertTextWidget

doc/expressions.md

@@ -406,7 +406,7 @@ The reduction relation is transitive, which is to say, is ``s`` reduces to ``s'`
 
 This last fact reflects the intuition that once we have proved a proposition ``p``, we only care that is has been proved; the proof does nothing more than witness the fact that ``p`` is true.
 
-Definitional equality is a strong notion of equality of values. Lean's logical foundations sanction treating definitionally equal terms as being the same when checking that a term is well-typed and/or that it has a given type.
+Definitional equality is a strong notion of equalty of values. Lean's logical foundations sanction treating definitionally equal terms as being the same when checking that a term is well-typed and/or that it has a given type.
 
 The reduction relation is believed to be strongly normalizing, which is to say, every sequence of reductions applied to a term will eventually terminate. The property guarantees that Lean's type-checking algorithm terminates, at least in principle. The consistency of Lean and its soundness with respect to set-theoretic semantics do not depend on either of these properties.
 

doc/faq.md

@@ -7,6 +7,15 @@ Lean is a new open source theorem prover being developed at Microsoft Research.
 It is a research project that aims to bridge the gap between interactive and automated theorem proving.
 Lean can be also used as a programming language. Actually, some Lean features are implemented in Lean itself.
 
+### Are pull requests welcome?
+
+In the past, we accepted most pull requests. This practice produced hard to maintain code, performance problems, and bugs.
+It takes time to review a pull request and make sure it is correct, useful and is not in conflict with our plans.
+Small bug fixes (few lines of code) are always welcome. Any other kind of unrequested pull request is not.
+Thus, before implementing a feature or modifying the system, please ask whether the change is welcome or not.
+We have issues tagged with ["help wanted"](https://github.com/leanprover/lean4/issues?q=is%3Aissue+is%3Aopen+label%3A%22help+wanted%22), if you want to contribute to the project, please take a look at them.
+If you are interested in one of them, post comments, ask questions, and engage with the core developers there.
+
 ### Should I use Lean?
 
 Lean is under heavy development, and we are constantly trying new
@@ -27,7 +36,7 @@ It is a good place to interact with other Lean users.
 ### Should I use Lean to teach a course?
 
 Lean has been used to teach courses on logic, type theory and programming languages at CMU and the University of Washington.
-The lecture notes for the CMU course [Logic and Proof](https://lean-lang.org/logic_and_proof) are available online,
+The lecture notes for the CMU course [Logic and Proof](https://leanprover.github.io/logic_and_proof) are available online,
 but they are for Lean 3.
 If you decide to teach a course using Lean, we suggest you prepare all material before the beginning of the course, and
 make sure that Lean attends all your needs. You should not expect we will fix bugs and/or add features needed for your course.
@@ -47,7 +56,7 @@ We expect similar independent checkers will be built for Lean 4.
 
 We use [GitHub](https://github.com/leanprover/lean4/issues) to track bugs and new features.
 Bug reports are always welcome, but nitpicking issues are not (e.g., the error message is confusing).
-See also our [contribution guidelines](https://github.com/leanprover/lean4/blob/master/CONTRIBUTING.md).
+See also our [contribution guidelines](../CONTRIBUTING.md).
 
 ### Is it Lean, LEAN, or L∃∀N?
 

doc/flake.lock

@@ -19,11 +19,11 @@
     },
     "flake-utils": {
       "locked": {
-        "lastModified": 1656928814,
-        "narHash": "sha256-RIFfgBuKz6Hp89yRr7+NR5tzIAbn52h8vT6vXkYjZoM=",
+        "lastModified": 1644229661,
+        "narHash": "sha256-1YdnJAsNy69bpcjuoKdOYQX0YxZBiCYZo4Twxerqv7k=",
         "owner": "numtide",
         "repo": "flake-utils",
-        "rev": "7e2a3b3dfd9af950a856d66b0a7d01e3c18aa249",
+        "rev": "3cecb5b042f7f209c56ffd8371b2711a290ec797",
         "type": "github"
       },
       "original": {
@@ -35,13 +35,14 @@
     "lean": {
       "inputs": {
         "flake-utils": "flake-utils",
+        "lean-stage0": "lean-stage0",
         "lean4-mode": "lean4-mode",
         "nix": "nix",
         "nixpkgs": "nixpkgs_2"
       },
       "locked": {
         "lastModified": 0,
-        "narHash": "sha256-YnYbmG0oou1Q/GE4JbMNb8/yqUVXBPIvcdQQJHBqtPk=",
+        "narHash": "sha256-AfBkKX6Ahb9YbZke+eWLmsUk1Z9BwdJ1CpIoPY8Msx8=",
         "path": "../.",
         "type": "path"
       },
@@ -50,14 +51,29 @@
         "type": "path"
       }
     },
+    "lean-stage0": {
+      "locked": {
+        "lastModified": 0,
+        "narHash": "sha256-3K/43lSW4WIHNG+HHVKCD1odS63mHuaQ4ueHyTIkcls=",
+        "owner": "leanprover",
+        "repo": "lean4",
+        "rev": "0000000000000000000000000000000000000000",
+        "type": "github"
+      },
+      "original": {
+        "owner": "leanprover",
+        "repo": "lean4",
+        "type": "github"
+      }
+    },
     "lean4-mode": {
       "flake": false,
       "locked": {
-        "lastModified": 1659020985,
-        "narHash": "sha256-+dRaXB7uvN/weSZiKcfSKWhcdJVNg9Vg8k0pJkDNjpc=",
+        "lastModified": 1647694750,
+        "narHash": "sha256-0rV61KhevG9IAjZDN2Ts2VS65fiUAPAezbf282u7yy8=",
         "owner": "leanprover",
         "repo": "lean4-mode",
-        "rev": "37d5c99b7b29c80ab78321edd6773200deb0bca6",
+        "rev": "c016c7aeee92564836355083664c49ed57024427",
         "type": "github"
       },
       "original": {
@@ -69,16 +85,15 @@
     "leanInk": {
       "flake": false,
       "locked": {
-        "lastModified": 1704976501,
-        "narHash": "sha256-FSBUsbX0HxakSnYRYzRBDN2YKmH9EkA0q9p7TSPEJTI=",
+        "lastModified": 1656863690,
+        "narHash": "sha256-9tmynTTeJGhYZaltS4xhSJgLTpe7Ta1ofV6U1SA/5V4=",
         "owner": "leanprover",
         "repo": "LeanInk",
-        "rev": "51821e3c2c032c88e4b2956483899d373ec090c4",
+        "rev": "4b5e606ea8cc54c2447ce48706f8ec1d133d19e9",
         "type": "github"
       },
       "original": {
         "owner": "leanprover",
-        "ref": "refs/pull/57/merge",
         "repo": "LeanInk",
         "type": "github"
       }
@@ -122,11 +137,11 @@
         "nixpkgs-regression": "nixpkgs-regression"
       },
       "locked": {
-        "lastModified": 1657097207,
-        "narHash": "sha256-SmeGmjWM3fEed3kQjqIAO8VpGmkC2sL1aPE7kKpK650=",
+        "lastModified": 1648022028,
+        "narHash": "sha256-HtwmifW6STPcym+3uJ4YavgTKTYVIoiQHg3f0wXOm+Q=",
         "owner": "NixOS",
         "repo": "nix",
-        "rev": "f6316b49a0c37172bca87ede6ea8144d7d89832f",
+        "rev": "98ce1a21b7d959c5575fac566c8699e91703a9f7",
         "type": "github"
       },
       "original": {
@@ -137,18 +152,17 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1653988320,
-        "narHash": "sha256-ZaqFFsSDipZ6KVqriwM34T739+KLYJvNmCWzErjAg7c=",
+        "lastModified": 1632864508,
+        "narHash": "sha256-d127FIvGR41XbVRDPVvozUPQ/uRHbHwvfyKHwEt5xFM=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "2fa57ed190fd6c7c746319444f34b5917666e5c1",
+        "rev": "82891b5e2c2359d7e58d08849e4c89511ab94234",
         "type": "github"
       },
       "original": {
-        "owner": "NixOS",
-        "ref": "nixos-22.05-small",
-        "repo": "nixpkgs",
-        "type": "github"
+        "id": "nixpkgs",
+        "ref": "nixos-21.05-small",
+        "type": "indirect"
       }
     },
     "nixpkgs-regression": {
@@ -161,19 +175,18 @@
         "type": "github"
       },
       "original": {
-        "owner": "NixOS",
-        "repo": "nixpkgs",
+        "id": "nixpkgs",
         "rev": "215d4d0fd80ca5163643b03a33fde804a29cc1e2",
-        "type": "github"
+        "type": "indirect"
       }
     },
     "nixpkgs_2": {
       "locked": {
-        "lastModified": 1657208011,
-        "narHash": "sha256-BlIFwopAykvdy1DYayEkj6ZZdkn+cVgPNX98QVLc0jM=",
+        "lastModified": 1648219316,
+        "narHash": "sha256-Ctij+dOi0ZZIfX5eMhgwugfvB+WZSrvVNAyAuANOsnQ=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "2770cc0b1e8faa0e20eb2c6aea64c256a706d4f2",
+        "rev": "30d3d79b7d3607d56546dd2a6b49e156ba0ec634",
         "type": "github"
       },
       "original": {

doc/flake.nix

@@ -4,15 +4,15 @@
   inputs.lean.url = path:../.;
   inputs.flake-utils.follows = "lean/flake-utils";
   inputs.mdBook = {
-    url = "github:leanprover/mdBook";
+    url = github:leanprover/mdBook;
     flake = false;
   };
   inputs.alectryon = {
-    url = "github:Kha/alectryon/typeid";
+    url = github:Kha/alectryon/typeid;
     flake = false;
   };
   inputs.leanInk = {
-    url = "github:leanprover/LeanInk/refs/pull/57/merge";
+    url = github:leanprover/LeanInk;
     flake = false;
   };
 
@@ -27,7 +27,7 @@
         src = inputs.mdBook;
         cargoDeps = drv.cargoDeps.overrideAttrs (_: {
           inherit src;
-          outputHash = "sha256-1YlPS6cqgxE4fjy9G8pWrpP27YrrbCDnfeyIsX81ZNw=";
+          outputHash = "sha256-mhTWHs/bsmm3FH59SkUxBTl5lEH2Rlz/aF9CuBTu1TE=";
         });
         doCheck = false;
       });
@@ -78,30 +78,22 @@
           (with python3Packages; [ pygments dominate beautifulsoup4 docutils ]);
         doCheck = false;
       };
-      renderLeanMod = mod: mod.overrideAttrs (final: prev: {
-        name = "${prev.name}.md";
-        buildInputs = prev.buildInputs ++ [ alectryon ];
-        outputs = [ "out" ];
-        buildCommand = ''
-          dir=$(dirname $relpath)
-          mkdir -p $dir out/$dir
-          if [ -d $src ]; then cp -r $src/. $dir/; else cp $src $leanPath; fi
-          alectryon --frontend lean4+markup $leanPath --backend webpage -o $out/$leanPath.md
-        '';
-      });
-      renderPackage = pkg: symlinkJoin {
-        name = "${pkg.name}-mds";
-        paths = map renderLeanMod (lib.attrValues pkg.mods);
-      };
-      literate = buildLeanPackage {
-        name = "literate";
-        src = ./.;
-        roots = [
-          { mod = "examples"; glob = "submodules"; }
-          { mod = "monads"; glob = "submodules"; }
-        ];
-      };
-      inked = renderPackage literate;
+      renderLean = name: file: runCommandNoCC "${name}.md" { buildInputs = [ alectryon ]; } ''
+        mkdir -p $(basename $out/${name})
+        alectryon --frontend lean4+markup ${file} --backend webpage -o $out/${name}.md
+      '';
+      listFilesRecursiveRel = root: dir: lib.flatten (lib.mapAttrsToList (name: type:
+        if type == "directory" then
+          listFilesRecursiveRel root ("${dir}/${name}")
+        else
+          dir + "/${name}"
+      ) (builtins.readDir "${root}/${dir}"));
+      renderDir = dir: let
+        inputs = builtins.filter (n: builtins.match ".*\.lean" n != null) (listFilesRecursiveRel dir ".");
+        outputs = lib.genAttrs inputs (n: renderLean n "${dir}/${n}");
+      in
+        outputs // symlinkJoin { inherit name; paths = lib.attrValues outputs; };
+      inked = renderDir ./.;
       doc = book;
     };
     defaultPackage = self.packages.${system}.doc;

doc/fplean.md

@@ -1,7 +1,7 @@
 Functional Programming in Lean
 =======================
 
-The goal of [this book](https://lean-lang.org/functional_programming_in_lean/) is to be an accessible introduction to using Lean 4 as a programming language.
+The goal of [this book](https://leanprover.github.io/functional_programming_in_lean/) is to be an accessible introduction to using Lean 4 as a programming language.
 It should be useful both to people who want to use Lean as a general-purpose programming language and to mathematicians who want to develop larger-scale proof automation but do not have a background in functional programming.
 It does not assume any background with functional programming, though it's probably not a good first book on programming in general.
 New content will be added once per month until it's done.

doc/functions.md

@@ -32,8 +32,8 @@ def fact x :=
 
 #eval fact 100
 ```
-By default, Lean only accepts total functions.
-The `partial` keyword may be used to define a recursive function without a termination proof; `partial` functions compute in compiled programs, but are opaque in proofs and during type checking.
+By default, Lean only accepts total functions. The `partial` keyword should be used when Lean cannot
+establish that a function always terminates.
 ```lean
 partial def g (x : Nat) (p : Nat -> Bool) : Nat :=
   if p x then

doc/highlight.js

@@ -1143,7 +1143,7 @@ hljs.registerLanguage("lean", function(hljs) {
       'sorry admit',
   };
 
-  var LEAN_IDENT_RE = /[A-Za-z_][\\w\u207F-\u209C\u1D62-\u1D6A\u2079\'0-9?]*/;
+  var LEAN_IDENT_RE = /[A-Za-z_][\\w\u207F-\u209C\u1D62-\u1D6A\u2079\'0-9]*/;
 
   var DASH_COMMENT = hljs.COMMENT('--', '$');
   var MULTI_LINE_COMMENT = hljs.COMMENT('/-[^-]', '-/');
@@ -1167,7 +1167,7 @@ hljs.registerLanguage("lean", function(hljs) {
 
   var LEAN_DEFINITION =	{
     className: 'theorem',
-    begin: '\\b(def|theorem|lemma|class|structure|(?<!deriving\\s+)instance)\\b',
+    beginKeywords: 'def theorem lemma class instance structure',
     end: ':= | where',
     excludeEnd: true,
     contains: [

doc/inductive.md

@@ -1,3 +1,3 @@
 # Inductive Types
 
-[Theorem Proving in Lean](https://lean-lang.org/theorem_proving_in_lean4/inductive_types.html) has a chapter about inductive datatypes.
+[Theorem Proving in Lean](https://leanprover.github.io/theorem_proving_in_lean4/inductive_types.html) has a chapter about inductive datatypes.

doc/latex/lstlean.tex

@@ -4,7 +4,7 @@
 
 \lstdefinelanguage{lean} {
 
-% Anything between $ becomes LaTeX math mode
+% Anything betweeen $ becomes LaTeX math mode
 mathescape=false,
 % Comments may or not include Latex commands
 texcl=false,
@@ -201,7 +201,6 @@ literate=
 
 {ₙ}{{\ensuremath{_n}}}1
 {ₘ}{{\ensuremath{_m}}}1
-{ₚ}{{\ensuremath{_p}}}1
 {↑}{{\ensuremath{\uparrow}}}1
 {↓}{{\ensuremath{\downarrow}}}1
 
@@ -265,7 +264,7 @@ columns=[l]fullflexible,
 % Style for (listings') identifiers
 identifierstyle={\ttfamily\color{black}},
 % Note : highlighting of Coq identifiers is done through a new
-% delimiter definition through an lstset at the beginning of the
+% delimiter definition through an lstset at the begining of the
 % document. Don't know how to do better.
 
 % Style for declaration keywords

doc/lean3changes.md

@@ -42,7 +42,7 @@ def Sum.str : Option Nat → String :=
 ## Implicit lambdas
 
 In Lean 3 stdlib, we find many [instances](https://github.com/leanprover/lean/blob/master/library/init/category/reader.lean#L39) of the dreadful `@`+`_` idiom.
-It is often used when the expected type is a function type with implicit arguments,
+It is often used when we the expected type is a function type with implicit arguments,
 and we have a constant (`reader_t.pure` in the example) which also takes implicit arguments. In Lean 4, the elaborator automatically introduces lambdas
 for consuming implicit arguments. We are still exploring this feature and analyzing its impact, but the experience so far has been very positive. As an example,
 here is the example in the link above using Lean 4 implicit lambdas.
@@ -85,7 +85,7 @@ def id5 : {α : Type} → α → α :=
 
 ## Sugar for simple functions
 
-In Lean 3, we can create simple functions from infix operators by using parentheses. For example, `(+1)` is sugar for `fun x, x + 1`. In Lean 4, we generalize this notation using `·` as a placeholder. Here are a few examples:
+In Lean 3, we can create simple functions from infix operators by using parentheses. For example, `(+1)` is sugar for `fun x, x + 1`. In Lean 4, we generalize this notation using `·` As a placeholder. Here are a few examples:
 
 ```lean
 # namespace ex3
@@ -196,8 +196,6 @@ example (f : Nat → Nat) (a b c : Nat) : f (a + b + c) = f (a + (b + c)) :=
   congrArg f (Nat.add_assoc ..)
 ```
 
-In Lean 4, writing `f(x)` in place of `f x` is no longer allowed, you must use whitespace between the function and its arguments (e.g., `f (x)`).
-
 ## Dependent function types
 
 Given `α : Type` and `β : α → Type`, `(x : α) → β x` denotes the type of functions `f` with the property that,
@@ -289,11 +287,11 @@ Lean execution runtime. For example, we cannot prove in Lean that arrays have a
 the runtime used to execute Lean programs guarantees that an array cannot have more than 2^64 (2^32) elements
 in a 64-bit (32-bit) machine. We can take advantage of this fact to provide a more efficient implementation for
 array functions. However, the efficient version would not be very useful if it can only be used in
-unsafe code. Thus, Lean 4 provides the attribute `@[implemented_by functionName]`. The idea is to provide
+unsafe code. Thus, Lean 4 provides the attribute `@[implementedBy functionName]`. The idea is to provide
 an unsafe (and potentially more efficient) version of a safe definition or constant. The function `f`
-at the attribute `@[implemented_by f]` is very similar to an extern/foreign function,
+at the attribute `@[implementedBy f]` is very similar to an extern/foreign function,
 the key difference is that it is implemented in Lean itself. Again, the logical soundness of the system
-cannot be compromised by using the attribute `implemented_by`, but if the implementation is incorrect your
+cannot be compromised by using the attribute `implementedBy`, but if the implementation is incorrect your
 program may crash at runtime. In the following example, we define `withPtrUnsafe a k h` which
 executes `k` using the memory address where `a` is stored in memory. The argument `h` is proof
 that `k` is a constant function. Then, we "seal" this unsafe implementation at `withPtr`. The proof `h`
@@ -304,7 +302,7 @@ unsafe
 def withPtrUnsafe {α β : Type} (a : α) (k : USize → β) (h : ∀ u, k u = k 0) : β :=
   k (ptrAddrUnsafe a)
 
-@[implemented_by withPtrUnsafe]
+@[implementedBy withPtrUnsafe]
 def withPtr {α β : Type} (a : α) (k : USize → β) (h : ∀ u, k u = k 0) : β :=
   k 0
 ```
@@ -342,7 +340,8 @@ partial def f (x : Nat) : IO Unit := do
 
 These are changes to the library which may trip up Lean 3 users:
 
-- `List` is no longer a monad.
+- `Option` and `List` are no longer monads. Instead there is `OptionM`. This was done to avoid some performance traps. For example `o₁ <|> o₂` where `o₁ o₂ : Option α` will evaluate both `o₁` and `o₂` even if `o₁` evaluates to `some x`. This can be a problem if `o₂` requires a lot of compute to evaluate. A zulip discussion on this design choice is [here](https://leanprover.zulipchat.com/#narrow/stream/270676-lean4/topic/Option.20do.20notation.20regression.3F).
+
 
 ## Style changes
 

doc/lexical_structure.md

@@ -8,7 +8,7 @@ A Lean program consists of a stream of UTF-8 tokens where each token
 is one of the following:
 
 ```
-   token: symbol | command | ident | string | raw_string | char | numeral |
+   token: symbol | command | ident | string | char | numeral |
         : decimal | doc_comment | mod_doc_comment | field_notation
 ```
 
@@ -79,35 +79,15 @@ special characters:
 [Unicode table](https://unicode-table.com/en/) so "\xA9 Copyright 2021" is "© Copyright 2021".
 - `\uHHHH` puts the character represented by the 4 digit hexadecimal into the string, so the following
 string "\u65e5\u672c" will become "日本" which means "Japan".
-- `\` followed by a newline and then any amount of whitespace is a "gap" that is equivalent to the empty string,
-useful for letting a string literal span across multiple lines. Gaps spanning multiple lines can be confusing,
-so the parser raises an error if the trailing whitespace contains any newlines.
 
 So the complete syntax is:
 
 ```
    string       : '"' string_item '"'
-   string_item  : string_char | char_escape | string_gap
-   string_char  : [^"\\]
-   char_escape  : "\" ("\" | '"' | "'" | "n" | "t" | "x" hex_char{2} | "u" hex_char{4})
+   string_item  : string_char | string_escape
+   string_char  : [^\\]
+   string_escape: "\" ("\" | '"' | "'" | "n" | "t" | "x" hex_char{2} | "u" hex_char{4} )
    hex_char     : [0-9a-fA-F]
-   string_gap   : "\" newline whitespace*
-```
-
-Raw String Literals
-===================
-
-Raw string literals are string literals without any escape character processing.
-They begin with `r##...#"` (with zero or more `#` characters) and end with `"#...##` (with the same number of `#` characters).
-The contents of a raw string literal may contain `"##..#` so long as the number of `#` characters
-is less than the number of `#` characters used to begin the raw string literal.
-
-```
-   raw_string          : raw_string_aux(0) | raw_string_aux(1) | raw_string_aux(2) | ...
-   raw_string_aux(n)   : 'r' '#'{n} '"' raw_string_item '"' '#'{n}
-   raw_string_item(n)  : raw_string_char | raw_string_quote(n)
-   raw_string_char     : [^"]
-   raw_string_quote(n) : '"' '#'{0..n-1}
 ```
 
 Char Literals
@@ -116,9 +96,7 @@ Char Literals
 Char literals are enclosed by single quotes (``'``).
 
 ```
-   char      : "'" char_item "'"
-   char_item : char_char | char_escape
-   char_char : [^'\\]
+   char: "'" string_item "'"
 ```
 
 Numeric Literals

doc/macro_overview.md

@@ -1,7 +1,7 @@
 
 # Macro Overview
 
-The official paper describing the mechanics behind Lean 4's macro system can be
+The offical paper describing the mechanics behind Lean 4's macro system can be
 found in [Beyond Notations: Hygienic Macro Expansion for Theorem Proving
 Languages](https://arxiv.org/abs/2001.10490) by Sebastian Ullrich and Leonardo
 de Moura, and the accompanying repo with example code can be found in the
@@ -68,7 +68,7 @@ carries state needed for macro expansion to work nicely, including the info
 needed to implement hygiene.
 
 As an example, we again refer to Mathlib's set builder notation:
-```lean
+```
 /- Declares a parser -/
 syntax (priority := high) "{" term,+ "}" : term
 
@@ -95,8 +95,7 @@ simplified representation which omits details in the `atom` and `ident`
 constructors; users can create atoms and idents which comport with this
 simplified representation using the `mkAtom` and `mkIdent` methods provided in
 the `Lean` namespace.
-```lean
-# open Lean
+```
 inductive Syntax where
   | missing : Syntax
   | node (kind : SyntaxNodeKind) (args : Array Syntax) : Syntax
@@ -107,14 +106,12 @@ inductive Syntax where
 
 
 For those interested, `MacroM` is a `ReaderT`:
-```lean
-# open Lean
+```
 abbrev MacroM := ReaderT Macro.Context (EStateM Macro.Exception Macro.State)
 ```
 
 The other relevant components are defined as follows:
-```lean
-# open Lean
+```
 structure Context where
   methods        : MethodsRef
   mainModule     : Name
@@ -151,7 +148,7 @@ or mathlib4's `binderterm`. These are the different categories of things that
 can be referred to in a quote/antiquote. `declare_syntax_cat` results in a call
 to `registerParserCategory` and produces a new parser descriptor:
 
-```lean
+```
 set_option trace.Elab.definition true in
 declare_syntax_cat binderterm
 
@@ -181,8 +178,7 @@ macro/pattern language by way of the `syntax` keyword. This is the recommended
 means of writing parsers. As an example, the parser for the `rwa` (rewrite, then
 use assumption) tactic is:
 
-```lean
-# open Lean.Parser.Tactic
+```
 set_option trace.Elab.definition true in
 syntax "rwa " rwRuleSeq (location)? : tactic
 
@@ -211,17 +207,15 @@ mark, which is not what we want.
 The name `tacticRwa__` is automatically generated. You can name parser
 descriptors declared with the `syntax` keyword like so:
 
-```lean
+```
 set_option trace.Elab.definition true in
 syntax (name := introv) "introv " (colGt ident)* : tactic
 
-/-
 [Elab.definition.body] introv : Lean.ParserDescr :=
 Lean.ParserDescr.node `introv 1022
   (Lean.ParserDescr.binary `andthen (Lean.ParserDescr.nonReservedSymbol "introv " false)
     (Lean.ParserDescr.unary `many
       (Lean.ParserDescr.binary `andthen (Lean.ParserDescr.const `colGt) (Lean.ParserDescr.const `ident))))
--/
 ```
 
 ## The pattern language
@@ -257,7 +251,7 @@ pretty printed output.
 ## Syntax expansions with `macro_rules`, and how it desugars.
 
 `macro_rules` lets you declare expansions for a given `Syntax` element using a
-syntax similar to a `match` statement. The left-hand side of a match arm is a
+syntax simlar to a `match` statement. The left-hand side of a match arm is a
 quotation (with a leading `<cat>|` for categories other than `term` and
 `command`) in which users can specify the pattern they'd like to write an
 expansion for. The right-hand side returns a syntax quotation which is the
@@ -274,7 +268,7 @@ declared with `macro_rules`. This `transitivity` tactic is implemented such that
 it will work for either Nat.le or Nat.lt. The Nat.lt version was declared "most
 recently", so it will be tried first, but if it fails (for example, if the
 actual term in question is Nat.le) the next potential expansion will be tried:
-```lean
+```
 macro "transitivity" e:(colGt term) : tactic => `(tactic| apply Nat.le_trans (m := $e))
 macro_rules
   | `(tactic| transitivity $e) => `(tactic| apply Nat.lt_trans (m := $e))
@@ -289,20 +283,18 @@ example (a b c : Nat) (h0 : a <= b) (h1 : b <= c) : a <= c := by
 
 /- This will fail, but is interesting in that it exposes the "most-recent first" behavior, since the
   error message complains about being unable to unify mvar1 <= mvar2, rather than mvar1 < mvar2. -/
-/-
 example (a b c : Nat) (h0 : a <= b) (h1 : b <= c) : False := by
   transitivity b <;>
   assumption
--/
 ```
 
 To see the desugared definition of the actual expansion, we can again use
 `set_option trace.Elab.definition true in` and observe the output of the humble
 `exfalso` tactic defined in Mathlib4:
-```lean
+```
 
 set_option trace.Elab.definition true in
-macro "exfalso" : tactic => `(tactic| apply False.elim)
+macro "exfalso" : tactic => `(apply False.elim)
 
 /-
 Results in the expansion:
@@ -336,8 +328,7 @@ fun x =>
 We can also create the syntax transformer declaration ourselves instead of using
 `macro_rules`. We'll need to name our parser and use the attribute `@[macro
 myExFalsoParser]` to associate our declaration with the parser:
-```lean
-# open Lean
+```
 syntax (name := myExfalsoParser) "myExfalso" : tactic
 
 -- remember that `Macro` is a synonym for `Syntax -> TacticM Unit`
@@ -352,12 +343,12 @@ example (p : Prop) (h : p) (f : p -> False) : 3 = 2 := by
 In the above example, we're still using the sugar Lean provides for creating
 quotations, as it feels more intuitive and saves us some work. It is possible to
 forego the sugar altogether:
-```lean
+```
 syntax (name := myExfalsoParser) "myExfalso" : tactic
 
 @[macro myExfalsoParser] def implMyExfalso : Lean.Macro :=
-  fun stx => pure (Lean.mkNode `Lean.Parser.Tactic.apply
-    #[Lean.mkAtomFrom stx "apply", Lean.mkCIdentFrom stx ``False.elim])
+  fun stx => Lean.mkNode `Lean.Parser.Tactic.apply
+    #[Lean.mkAtomFrom stx "apply", Lean.mkCIdentFrom stx ``False.elim]
 
 example (p : Prop) (h : p) (f : p -> False) : 3 = 2 := by
   myExfalso

doc/make/index.md

@@ -10,9 +10,12 @@ Platform-Specific Setup
 
 - [Linux (Ubuntu)](ubuntu.md)
 - [Windows (msys2)](msys2.md)
+- [Windows (Visual Studio)](msvc.md)
 - [Windows (WSL)](wsl.md)
 - [macOS (homebrew)](osx-10.9.md)
 - Linux/macOS/WSL via [Nix](https://nixos.org/nix/): Call `nix-shell` in the project root. That's it.
+- There is also an [**experimental** setup based purely on Nix](nix.md) that works fundamentally differently from the
+  make/CMake setup described on this page.
 
 Generic Build Instructions
 --------------------------

doc/make/nix.md

@@ -0,0 +1,110 @@
+# Building with Nix
+
+While [Nix](https://nixos.org/nix/) can be used to quickly open a shell with all dependencies for the [standard setup](index.md) installed, the user-facing [Nix Setup](../setup.md#nix-setup) can also be used to work *on* Lean.
+
+## Setup
+
+Follow the setup in the link above; to open the Lean shell inside a Lean checkout, you can also use
+```bash
+# in the Lean root directory
+$ nix-shell -A nix
+```
+
+On top of the local and remote Nix cache, we do still rely on CCache as well to make C/C++ build steps incremental, which are atomic steps from Nix's point of view.
+To enable CCache, add the following line to the config file mentioned in the setup:
+```bash
+extra-sandbox-paths = /nix/var/cache/ccache
+```
+Then set up that directory as follows:
+```bash
+sudo mkdir -m0770 -p /nix/var/cache/ccache
+# macOS standard chown doesn't support --reference
+nix shell .#nixpkgs.coreutils -c sudo chown --reference=/nix/store /nix/var/cache/ccache
+```
+
+## Basic Build Commands
+
+From the Lean root directory inside the Lean shell:
+```bash
+nix build .#stage1  # build this stage's stdlib & executable
+nix build .#stage1.test  # run all tests
+nix run .#stage1.update-stage0  # update ./stage0 from this stage
+nix run .#stage1.update-stage0-commit  # ...and commit the results
+```
+The `stage1.` part in each command is optional:
+```bash
+nix build .#test  # run tests for stage 1
+nix build .  # build stage 1
+nix build  # ditto
+```
+
+## Build Process Description
+
+The Nix build process conceptually works the same as described in [Lean Build Pipeline](index.md#lean-build-pipeline).
+However, there are two important differences in practice apart from the standard Nix properties (hermeneutic, reproducible builds stored in a global hash-indexed store etc.):
+* Only files tracked by git (using `git add` or at least `git add --intent-to-add`) are compiled.
+This is actually a general property of Nix flakes, and has the benefit of making it basically impossible to forget to commit a file (at least in `src/`).
+* Only files reachable from `src/Lean.lean` are compiled.
+This is because modules are discovered not from a directory listing anymore but by recursively compiling all dependencies of that top module.
+
+## Editor Integration
+
+As in the standard Nix setup.
+After adding `src/` as an LSP workspace, it should automatically fall back to using stage 0 in there.
+
+Note that the UX of `{emacs,vscode}-dev` is quite different from the Make-based setup regarding the compilation of dependencies:
+there is no mutable directory incrementally filled by the build that we could point the editor at for .olean files.
+Instead, `emacs-dev` will gather the individual dependency outputs from the Nix store when checking a file -- and build them on the fly when necessary.
+However, it will only ever load changes saved to disk, not ones opened in other buffers.
+
+The absence of a mutable output directory also means that the Lean server will not automatically pick up `.ilean` metadata from newly compiled files.
+Instead, you can run `nix run .#link-ilean` to symlink the `.ilean` tree of the stdlib state at that point in time to `src/build/lib`, where the server should automatically find them.
+
+## Other Fun Stuff to Do with Nix
+
+Open Emacs with Lean set up from an arbitrary commit (without even cloning Lean beforehand... if your Nix is new enough):
+```bash
+nix run github:leanprover/lean4/7e4edeb#emacs-package
+```
+
+Open a shell with `lean` and `LEAN_PATH` set up for compiling a specific module (this is exactly what `emacs-dev` is doing internally):
+```bash
+nix develop .#mods.\"Lean.Parser.Basic\"
+# alternatively, directly pass a command to execute:
+nix develop .#stage2.mods.\"Init.Control.Basic\" -c bash -c 'lean $src -Dtrace.Elab.command=true'
+```
+
+Not sure what you just broke? Run Lean from (e.g.) the previous commit on a file:
+```bash
+nix run .\?rev=$(git rev-parse @^) scratch.lean
+```
+
+Work on two adjacent stages at the same time without the need for repeatedly updating and reverting `stage0/`:
+```bash
+# open an editor that will use only committed changes (so first commit them when changing files)
+nix run .#HEAD-as-stage1.emacs-dev&
+# open a second editor that will use those commited changes as stage 0
+# (so don't commit changes done here until you are done and ran a final `update-stage0-commit`)
+nix run .#HEAD-as-stage0.emacs-dev&
+```
+To run `nix build` on the second stage outside of the second editor, use
+```bash
+nix build .#stage0-from-input --override-input lean-stage0 .\?rev=$(git rev-parse HEAD)
+```
+This setup will inadvertently change your `flake.lock` file, which you can revert when you are done.
+
+...more surely to come...
+
+## Debugging
+
+Since Nix copies all source files before compilation, you will need to map debug symbols back to the original path using `set substitute-path` in GDB.
+For example, for a build on Linux with the Nix sandbox activated:
+```bash
+(gdb) f
+#1  0x0000000000d23a4f in lean_inc (o=0x1) at /build/source/build/include/lean/lean.h:562
+562	/build/source/build/include/lean/lean.h: No such file or directory.
+(gdb) set substitute-path /build/source/build src
+(gdb) f
+#1  0x0000000000d23a4f in lean_inc (o=0x1) at /build/source/build/include/lean/lean.h:562
+562	static inline void lean_inc(lean_object * o) { if (!lean_is_scalar(o)) lean_inc_ref(o); }
+```

doc/metaprogramming-arith.md

@@ -60,7 +60,7 @@ While parsing `a * (b + c)`, `(b + c)` is assigned a precedence `60` by the addi
 the right argument to have precedence **at least** 71. Thus, this parse is invalid. In contrast, `(a * b) + c` assigns
 a precedence of `70` to `(a * b)`. This is compatible with addition which expects the left argument to have precedence
 **at least `60` ** (`70` is greater than `60`). Thus, the string `a * b + c` is parsed as `(a * b) + c`.
-For more details, please look at the [Lean manual on syntax extensions](./notation.md#notations-and-precedence).
+For more details, please look at the [Lean manual on syntax extensions](../syntax.md#notations-and-precedence).
 
 To go from strings into `Arith`, we define a macro to
 translate the syntax category `arith` into an `Arith` inductive value that

doc/monads/applicatives.lean

@@ -8,7 +8,7 @@ Let's see how they work!
 
 ## What is an Applicative Functor?
 
-An applicative functor defines a default or "base" construction for an object and allows
+An applicative functor is an defines a default or "base" construction for an object and allows
 function application to be chained across multiple instances of the structure. All applicative
 functors are functors, meaning they must also support the "map" operation.
 
@@ -29,30 +29,24 @@ simply from outside the structure, as was the case with `Functor.map`.
 
 Applicative in Lean is built on some helper type classes, `Functor`, `Pure` and `Seq`:
 
--/
-namespace hidden -- hidden
+```lean,ignore
 class Applicative (f : Type u → Type v) extends Functor f, Pure f, Seq f, SeqLeft f, SeqRight f where
-  map      := fun x y => Seq.seq (pure x) fun _ => y
-  seqLeft  := fun a b => Seq.seq (Functor.map (Function.const _) a) b
-  seqRight := fun a b => Seq.seq (Functor.map (Function.const _ id) a) b
-end hidden -- hidden
-/-!
+```
+
 Notice that as with `Functor` it is also a type transformer `(f : Type u → Type v)` and notice the
-`extends Functor f` is ensuring the base `Functor` also performs that same type transformation.
+`extends Functor f` is ensuring the base Functor also performs that same type transformation.
 
 As stated above, all applicatives are then functors. This means you can assume that `map` already
 exists for all these types.
 
 The `Pure` base type class is a very simple type class that supplies the `pure` function.
 
--/
-namespace hidden -- hidden
+```lean,ignore
 class Pure (f : Type u → Type v) where
    pure {α : Type u} : α → f α
-end hidden -- hidden
-/-!
+```
 
-You can think of it as lifting the result of a pure value to some monadic type. The simplest example
+You can think of it as lifing the result of a pure value to some monadic type. The simplest example
 of `pure` is the `Option` type:
 
 -/
@@ -71,12 +65,10 @@ instance : Monad Option where
 The `Seq` type class is also a simple type class that provides the `seq` operator which can
 also be written using the special syntax `<*>`.
 
--/
-namespace hidden -- hidden
+```lean,ignore
 class Seq (f : Type u → Type v) : Type (max (u+1) v) where
   seq : {α β : Type u} → f (α → β) → (Unit → f α) → f β
-end hidden -- hidden
-/-!
+```
 
 
 ## Basic Applicative Examples
@@ -212,7 +204,7 @@ so you get a nice zipped list like this:
 -- [(1, 4), (2, 5), (3, 6)]
 /-!
 
-And of course, as you would expect, there is an `unzip` also:
+And of couse, as you would expect, there is an `unzip` also:
 
 -/
 #eval List.unzip (List.zip [1, 2, 3] [4, 5, 6])
@@ -256,7 +248,7 @@ Applicative functor.
 
 You may remember seeing the `SeqLeft` and `SeqRight` base types on `class Applicative` earlier.
 These provide the `seqLeft` and `seqRight` operations which also have some handy notation
-shorthands `<*` and `*>` respectively. Where: `x <* y` evaluates `x`, then `y`, and returns the
+shorthands `<*` and `*>` repsectively. Where: `x <* y` evaluates `x`, then `y`, and returns the
 result of `x` and `x *> y` evaluates `x`, then `y`,  and returns the result of `y`.
 
 To make it easier to remember, notice that it returns that value that the `<*` or `*>` notation is
@@ -286,13 +278,13 @@ But you will need to understand full Monads before this will make sense.
 Diving a bit deeper, (you can skip this and jump to the [Applicative
 Laws](laws.lean.md#what-are-the-applicative-laws) if don't want to dive into this implementation detail right
 now). But, if you write a simple `Option` example `(.*.) <$> some 4 <*> some 5` that produces `some 20`
-using `Seq.seq` you will see something interesting:
+using `Seq.seq` you will see somthing interesting:
 
 -/
 #eval Seq.seq ((.*.) <$> some 4) (fun (_ : Unit) => some 5) -- some 20
 /-!
 
-This may look a bit cumbersome, specifically, why did we need to invent this funny looking function
+This may look a bit combersome, specifically, why did we need to invent this funny looking function
 `fun (_ : Unit) => (some 5)`?
 
 Well if you take a close look at the type class definition:

doc/monads/except.lean

@@ -48,7 +48,6 @@ And now you can run this test and get the expected exception:
 #eval test      -- Except.error "can't divide by zero"
 /-!
 
-
 ## Chaining
 
 Now as before you can build a chain of monadic actions that can be composed together using `bind (>>=)`:
@@ -71,17 +70,7 @@ def chainUsingDoNotation := do
 
 /-!
 Notice in the second `divide 6 0` the exception from that division was nicely propagated along
-to the final result and the square function was ignored in that case.  You can see why the
-`square` function was ignored if you look at the implementation of `Except.bind`:
--/
-def bind (ma : Except ε α) (f : α → Except ε β) : Except ε β :=
-  match ma with
-  | Except.error err => Except.error err
-  | Except.ok v      => f v
-/-!
-
-Specifically notice that it only calls the next function `f v` in the `Except.ok`, and
-in the error case it simply passes the same error along.
+to the final result and the square function was pretty much ignored in that case.
 
 Remember also that you can chain the actions with implicit binding by using the `do` notation
 as you see in the `chainUsingDoNotation` function above.
@@ -89,7 +78,7 @@ as you see in the `chainUsingDoNotation` function above.
 ## Try/Catch
 
 Now with all good exception handling you also want to be able to catch exceptions so your program
-can continue on or do some error recovery task, which you can do like this:
+can try continue on or do some error recovery task, which you can do like this:
 -/
 def testCatch :=
   try
@@ -139,8 +128,7 @@ def testUnwrap : String := Id.run do
 
 The `Id.run` function is a helper function that executes the `do` block and returns the result where
 `Id` is the _identity monad_.  So `Id.run do` is a pattern you can use to execute monads in a
-function that is not itself monadic.  This works for all monads except `IO` which, as stated earlier,
-you cannot invent out of thin air, you must use the `IO` monad given to your `main` function.
+function that is not itself monadic.
 
 ## Monadic functions
 
@@ -173,6 +161,6 @@ def forM [Monad m] (as : List α) (f : α → m PUnit) : m PUnit :=
 Now that you know all these different monad constructs, you might be wondering how you can combine
 them. What if there was some part of your state that you wanted to be able to modify (using the
 State monad), but you also needed exception handling. How can you get multiple monadic capabilities
-in the same function. To learn the answer, head to [Monad Transformers](transformers.lean.md).
+in the same fuunction. To learn the answer, head to [Monad Transformers](transformers.lean.md).
 
 -/

doc/monads/functors.lean

@@ -172,7 +172,7 @@ and now bringing it all together you can use the simple function `squareFeetToMe
 
 Lean also defines custom infix operator `<$>` for `Functor.map` which allows you to write this:
 -/
-#eval (fun s => s.length) <$> ["elephant", "tiger", "giraffe"] -- [8, 5, 7]
+#eval (fun s => s.length) <$> ["elephant", "tiger", "giraffe"]
 #eval (fun x => x + 1) <$> (some 5) -- some 6
 /-!
 
@@ -213,7 +213,7 @@ class Functor (f : Type u → Type v) : Type (max (u+1) v) where
 Note that `mapConst` has a default implementation, namely:
 `mapConst : {α β : Type u} → α → f β → f α := Function.comp map (Function.const _)` in the `Functor`
 type class.  So you can use this default implementation and you only need to replace it if
-your functor has a more specialized variant than this (usually the custom version is more performant).
+your Functors has a more specialized variant than this which is more performant.
 
 In general then, a functor is a function on types `F : Type u → Type v` equipped with an operator
 called `map` such that if you have a function `f` of type `α → β` then `map f` will convert your

doc/monads/intro.md

@@ -5,7 +5,7 @@ of [Category Theory](https://en.wikipedia.org/wiki/Monad_%28category_theory%29).
 
 Monads in Lean are so similar to Haskell that this introduction to monads is heavily based on the
 similar chapter of the [Monday Morning Haskell](https://mmhaskell.com/monads/). Many thanks to
-the authors of that material for allowing us to reuse it here.
+the authors of that material for allowing it to reused it here.
 
 Monads build on the following fundamental type classes which you will need to understand
 first before fully understanding monads. Shown in light blue are some concrete functors
@@ -29,10 +29,10 @@ still be summed up in a couple simple functions.  Here you will learn how to cre
 
 ## [Monads Tutorial](monads.lean.md)
 Now that you have an intuition for how abstract structures work, you'll examine some of the problems
-that functors and applicative functors don't help you solve. Then you'll learn the specifics of how
+that functors and applicative functors don't help you solve. Then you'll lean the specifics of how
 to actually use monads with some examples using the `Option` monad and the all important `IO` monad.
 
-## [Reader Monad](readers.lean.md)
+## [Reader Monads](readers.lean.md)
 Now that you understand the details of what makes a monadic structure work, in this section, you'll
 learn about one of the most useful built in monads `ReaderM`, which gives your programs a
 global read-only context.
@@ -45,19 +45,19 @@ of the things a function programming language supposedly "can't" do.
 ## [Except Monad](except.lean.md)
 
 Similar to the `Option` monad the `Except` monad allows you to change the signature of a function so
-that it can return an `ok` value or an `error` and it provides the classic exception handling
+that it can return an `ok` value or an `error` and it makes available the classic exception handling
 operations `throw/try/catch` so that your programs can do monad-based exception handling.
 
 ## [Monad Transformers](transformers.lean.md)
 
-Now that you are familiar with all the above monads it is time to answer the question - how you can
-make them work together? After all, there are definitely times when you need multiple kinds of
+Now that you are familiar with all the above monads it is time to answer the question of how you can
+make them work together. After all, there are definitely times when you need multiple kinds of
 monadic behavior. This section introduces the concept of monad transformers, which allow you to
 combine multiple monads into one.
 
 ## [Monad Laws](laws.lean.md)
-This section examines what makes a monad a legal monad. You could just implement your monadic type
-classes any way you want and write "monad" instances, but starting back with functors and
-applicative functors, you'll learn that all these structures have "laws" that they are expected to
-obey with respect to their behavior. You can make instances that don't follow these laws. But you do
-so at your peril, as other programmers will be very confused when they try to use them.
+This section examines what makes a monad a monad. After all, can't you just implement these type
+classes any way you want and write a "monad" instance? Starting back with functors and applicative
+functors, you'll learn that all these structures have "laws" that they are expected to obey with
+respect to their behavior. You can make instances that don't follow these laws. But you do so at
+your peril, as other programmers will be very confused when they try to use them.

doc/monads/laws.lean

@@ -46,7 +46,7 @@ as you will see below.
 
 Functors have two laws: the _identity_ law, and the _composition_ law. These laws express behaviors that
 your functor instances should follow. If they don't, other programmers will be very confused at the
-effect your instances have on their program.
+effect your instances have on their program. Many structures have similar laws, including monads.
 
 The identity law says that if you "map" the identity function (`id`) over your functor, the
 resulting functor should be the same. A succinct way of showing this on a `List` functor is:
@@ -65,7 +65,7 @@ def p1 : Point Nat := (Point.mk 1 2)
 #eval id <$> p1 == p1 -- false
 
 /-!
-Oh, and look while the `List` is behaving well, the `Point` functor fails this identity test.
+Oh, and look while the List is behaving well, the `Point` functor fails this identity test.
 
 The _composition_ law says that if you "map" two functions in succession over a functor, this
 should be the same as "composing" the functions and simply mapping that one super-function over the
@@ -149,9 +149,9 @@ example [Applicative m] [LawfulApplicative m] (v : m α) :
 
 `pure f <*> pure x = pure (f x)`
 
-Suppose you wrap a function and an object in `pure`. You can then apply the wrapped function over the
+Suppose you wrap a function and an object in pure. You can then apply the wrapped function over the
 wrapped object. Of course, you could also apply the normal function over the normal object, and then
-wrap it in `pure`. The homomorphism law states these results should be the same.
+wrap it in pure. The homomorphism law states these results should be the same.
 
 For example:
 
@@ -238,12 +238,8 @@ instance : Monad List  where
   pure := List.pure
   bind := List.bind
 
-def a := ["apple", "orange"]
-
-#eval a >>= pure      -- ["apple", "orange"]
-
-#eval a >>= pure = a  -- true
-
+#eval ["apple", "orange"] >>= pure  -- ["apple", "orange"]
+#eval [1,2,3] >>= pure              -- [1,2,3]
 /-!
 
 ### Right Identity
@@ -256,7 +252,7 @@ def z := 5
 #eval pure z >>= h                  -- some 6
 #eval h z                           -- some 6
 
-#eval pure z >>= h = h z            -- true
+#eval pure z >>= h = h x            -- true
 /-!
 
 So in this example, with this specific `z` and `h`, you see that the rule holds true.
@@ -316,7 +312,7 @@ There are two main ideas from all the laws:
 1. It should not matter what order you group operations in.  Another way to state this is function
    composition should hold across your structures.
 
-Following these laws will ensure other programmers are not confused by the behavior of your
+Following these laws will ensure other programmers are not confused by the bahavior of your
 new functors, applicatives and monads.
 
 -/

doc/monads/monads.lean

@@ -62,8 +62,8 @@ some kind.  Let's examine those function types:
 So `map` is a pure function, `seq` is a pure function wrapped in the structure, and `bind` takes a
 pure input but produces an output wrapped in the structure.
 
-Note: we are ignoring the `(Unit → f α)` function used by `seq` here since that has a special
-purpose explained in [Applicatives Lazy Evaluation](applicatives.lean.md#lazy-evaluation).
+Note: we are ignoring the `(Unit → f α)` function also used by `seq` in this comparison, since that
+was explained in [Applicatives Lazy Evaluation](applicatives.lean.md#lazy-evaluation).
 
 ## Basic Monad Example
 

doc/monads/readers.lean

@@ -3,13 +3,13 @@
 
 In the [previous section](monads.lean.md) you learned about the conceptual idea of monads. You learned
 what they are, and saw how some common types like `IO` and `Option` work as monads. Now in this
-section, you will be looking at some other useful monads. In particular, the `ReaderM` monad.
+part, you will be looking at some other useful monads. In particular, the `ReaderM` monad.
 
 ## How to do Global Variables in Lean?
 
 In Lean, your code is generally "pure", meaning functions can only interact with the arguments
 passed to them. This effectively means you cannot have global variables. You can have global
-definitions, but these are fixed at compile time. If some user behavior might change them, you would have
+definitions, but these are fixed at compile time. If some user behavior might change them, you have
 to wrap them in the `IO` monad, which means they can't be used from pure code.
 
 Consider this example. Here, you want to have an `Environment` containing different parameters as a
@@ -93,7 +93,7 @@ def main2 : IO Unit := do
 #eval main2 -- Result: 7538
 /-!
 The `ReaderM` monad provides a `run` method and it is the `ReaderM` run method that takes the initial
-`Environment` context.  So here you see `main2` loads the environment as before, and establishes
+`Environment` context.  So here you see `main2` loads the environment as before, and estabilishes
 the `ReaderM` context by passing `env` to the `run` method.
 
 > **Side note 1**: The `return` statement used above also needs some explanation.  The `return`
@@ -111,9 +111,9 @@ the monadic container type.
 
 > **Side note 2**: If the function `readerFunc3` also took some explicit arguments then you would have
 to write `(readerFunc3 args).run env` and this is a bit ugly, so Lean provides an infix operator
-`|>` that eliminates those parentheses so you can write `readerFunc3 args |>.run env` and then you can
+`|>` that eliminiates those parens so you can write `readerFunc3 args |>.run env` and then you can
 chain multiple monadic actions like this `m1 args1 |>.run args2 |>.run args3` and this is the
-recommended style.  You will see this pattern used heavily in Lean code.
+recommended style.  You will see this patten used heavily in Lean code.
 
 The `let env ← read` expression in `readerFunc1` unwraps the environment from the `ReaderM` so we
 can use it. Each type of monad might provide one or more extra functions like this, functions that
@@ -122,7 +122,8 @@ become available only when you are in the context of that monad.
 Here the `readerFunc2` function uses the `bind` operator `>>=` just to show you that there are bind
 operations happening here.  The `readerFunc3` function uses the `do` notation you learned about in
 [Monads](monads.lean.md) which hides that bind operation and can make the code look cleaner.
-So the expression `let x ← readerFunc2` is also calling the `bind` function under the covers,
+
+The `do` notation with `let x ← readerFunc2` is also calling the `bind` function under the covers,
 so that you can access the unwrapped value `x` needed for the `toString x` conversion.
 
 The important difference here to the earlier code is that `readerFunc3` and `readerFunc2` no longer
@@ -148,7 +149,7 @@ Now, remember in Lean that a function that takes an argument of type `Nat` and r
 like `def f (a : Nat) : String` is the same as this function `def f : Nat → String`.  These are
 exactly equal as types.  Well this is being used by the `ReaderM` Monad to add an input argument to
 all the functions that use the `ReaderM` monad and this is why `main` is able to start things off by
-simply passing that new input argument in `readerFunc3.run env`. So now that you know the implementation
+simply passing that new input argument in `readerFunc3 env`. So now that you know the implementation
 details of the `ReaderM` monad you can see that what it is doing looks very much like the original
 code we wrote at the beginning of this section, only it's taking a lot of the tedious work off your
 plate and it is creating a nice clean separation between what your pure functions are doing, and the
@@ -157,7 +158,7 @@ global context idea that the `ReaderM` adds.
 ## withReader
 
 One `ReaderM` function can call another with a modified version of the `ReaderM` context. You can
-use the `withReader` function from the `MonadWithReader` type class to do this:
+use the `withReader` function from the `MonadWithReader` typeclass to do this:
 
 -/
 def readerFunc3WithReader : ReaderM Environment String := do
@@ -165,8 +166,8 @@ def readerFunc3WithReader : ReaderM Environment String := do
   return "Result: " ++ toString x
 
 /-!
-Here we changed the `user` in the `Environment` context to "new user" and then we passed that
-modified context to `readerFunc2`.
+Here we changed the `user` in the `Environment` context to "new user" and then we
+passed that modified context to `readerFunc2`.
 
 So `withReader f m` executes monad `m` in the `ReaderM` context modified by `f`.
 
@@ -188,12 +189,6 @@ find that in larger code bases, with many different types of monads all composed
 greatly cleans up the code. Monads provide a beautiful functional way of managing cross-cutting
 concerns that would otherwise make your code very messy.
 
-Having this control over the inherited `ReaderM` context via `withReader` is actually very useful
-and something that is quite messy if you try and do this sort of thing with global variables, saving
-the old value, setting the new one, calling the function, then restoring the old value, making sure
-you do that in a try/finally block and so on. The `ReaderM` design pattern avoids that mess
-entirely.
-
 Now it's time to move on to [StateM Monad](states.lean.md) which is like a `ReaderM` that is
 also updatable.
 -/

doc/monads/states.lean

@@ -9,7 +9,7 @@ part, you will explore the `StateM` monad, which is like a `ReaderM` only the st
 
 ## Motivating example: Tic Tac Toe
 
-For this section, let's build a simple model for a Tic Tace Toe game. The main object is the `GameState`
+For this part, let's build a simple model for a Tic Tace Toe game. The main object is the `GameState`
 data type containing several important pieces of information. First and foremost, it has the
 "board", a map from 2D tile indices to the "Tile State" (X, O or empty). Then it also knows the
 current player, and it has a random generator.
@@ -59,7 +59,7 @@ provide an initial state, in addition to the computation to run. `StateM` then p
 the result of the computation combined with the final updated state.
 
 If you wish to discard the final state and just get the computation's result, you can use
-`run'` method instead.  Yes in Lean, the apostrophe can be part of a name, you read this "run
+`run'` method instead.  Yes in Lean, the apostraphe can be part of a name, you read this "run
 prime", and the general naming convention is that the prime method discards something.
 
 So for your Tic Tac Toe game, many of your functions will have a signature like `State GameState a`.
@@ -115,16 +115,12 @@ So finally, you can combine these functions together with `do` notation, and it
 clean! You don't need to worry about the side effects. The different monadic functions handle them.
 Here's a sample of what your function might look like to play one turn of the game. At the end, it
 returns a boolean determining if all the spaces have been filled.
-
-Notice in `isGameDone` and `nextTurn` we have stopped providing the full return type
-`StateM GameState Unit`.  This is because Lean is able to infer the correct monadic return type
-from the context and as a result the code is now looking really clean.
 -/
 
-def isGameDone := do
+def isGameDone : StateM GameState Bool := do
   return (← findOpen).isEmpty
 
-def nextTurn := do
+def nextTurn : StateM GameState Bool := do
   let i ← chooseRandomMove
   applyMove i
   isGameDone
@@ -153,7 +149,7 @@ def printBoard (board : Board) : IO Unit := do
       IO.println row
       row := []
 
-def playGame := do
+def playGame : StateM GameState Unit := do
   while true do
     let finished ← nextTurn
     if finished then return
@@ -190,8 +186,10 @@ at the reduced Type for `nextTurn`:
 So a function like `nextTurn` that might have just returned a `Bool` has been modified by the
 `StateM` monad such that the initial `GameState` is passed in as a new input argument, and the output
 value has been changed to the pair `Bool × GameState` so that it can return the pure `Bool` and the
-updated `GameState`.  So `playGame` then is automatically saving that updated game state so that each
-time around the `while` loop it is acting on the new state, otherwise that would be an infinite loop!
+updated `GameState`.  This is why the call to `nextTurn` looks like this: `let (_, g) := nextTurn gs`.
+This expression `(_, g)` conveniently breaks the pair up into 2 values, it doesn't care what the first
+value is (hence the underscore `_`), but it does need the updated state `g` which you can then assign
+back to the mutable `gs` variable to use next time around this loop.
 
 It is also interesting to see how much work the `do` and `←` notation are doing for you.  To
 implement the `nextTurn` function without these you would have to write this, manually plumbing
@@ -206,12 +204,6 @@ def nextTurnManually : StateM GameState Bool
 
 /-!
 
-This expression `let (i, gs)` conveniently breaks a returned pair up into 2 variables.
-In the expression `let (_, gs')` we didn't care what the first value was so we used underscore.
-Notice that nextTurn is capturing the updated game state from `chooseRandomMove` in the variable
-`gs`, which it is then passing to `applyMove` which returns `gs'` which is passed to `isGameDone`
-and that function returns `gs''` which we then return from `nextTurnManually`.  Phew, what a lot
-of work you don't have to do when you use `do` notation!
 
 ## StateM vs ReaderM
 
@@ -228,11 +220,6 @@ In this function `chooseRandomMove` is modifying the state that `applyMove` is g
 and `chooseRandomMove` knows nothing about `applyMove`.  So `StateM` functions can have this
 kind of downstream effect outside their own scope, whereas, `withReader` cannot do that.
 
-So there is no equivalent to `withReader` for `StateM`, besides you can always use the `StateM`
-`set` function to modify the state before calling the next function anyway.  You could however,
-manually call a `StateM` function like you see in `nextTurnManually` and completely override
-the state at any point that way.
-
 ## State, IO and other languages
 
 When thinking about Lean, it is often seen as a restriction that you can't have global variables or
@@ -255,7 +242,7 @@ your code cannot communicate with the outside world, you can be far more certain
 The `StateM` monad is also a more disciplined way of managing side effects. Top level code could
 call a `StateM` function multiple times with different independent initial states, even doing that
 across multiple tasks in parallel and each of these cannot clobber the state belonging to other
-tasks. Monadic code is more predictable and reusable than code that uses global variables.
+tasks. Monadic code is more reusable than code that uses global variables.
 
 ## Summary
 

doc/monads/transformers.lean

@@ -117,7 +117,7 @@ lifting.  You already used lifting in the above code, because you were able to c
 `parseArguments` which has a bigger type `StateT Config (ReaderT Arguments (Except String))`.
 This "just worked" because Lean did some magic with monad lifting.
 
-To give you a simpler example of this, suppose you have the following function:
+To give you a simpler example of this, suppose you have the following funciton:
 -/
 def divide (x : Float ) (y : Float): ExceptT String Id Float :=
   if y == 0 then
@@ -193,9 +193,9 @@ If you have an instance `MonadLift m n` that means there is a way to turn a comp
 inside of `m` into one that happens inside of `n` and (this is the key part) usually *without* the
 instance itself creating any additional data that feeds into the computation. This means you can in
 principle declare lifting instances from any monad to any other monad, it does not, however, mean
-that you should do this in all cases.  You can get a very nice report on how all this was done by
-adding the line `set_option trace.Meta.synthInstance true in` before `divideCounter` and moving you
-cursor to the end of the first line after `do`.
+that you should do this in all cases.  You can get a report from Lean of how all this was done by
+add the line `set_option trace.Meta.synthInstance true in` before main and moving the
+cursor to the end of the first line after `do` and you will see a nice detailed report.
 
 This was a lot of detail, but it is very important to understand how monad lifting works because it
 is used heavily in Lean programs.
@@ -225,7 +225,7 @@ instance  : MonadLift m (ReaderT ρ m) where
 This lift operation creates a function that defines the required `ReaderT` input
 argument, but the inner monad doesn't know or care about `ReaderT` so the
 monadLift function throws it away with the `_` then calls the inner monad action `x`.
-This is a perfectly legal implementation of the `ReaderM` monad.
+This is a perfectly legal and trivial way to implement a `ReaderM` monad.
 
 ## Add your own Custom MonadLift
 
@@ -270,10 +270,10 @@ def main3 : IO Unit := do
 #eval main3 -- (2.500000, 1)
 /-!
 
-It turns out that the `IO` monad you see in your `main` function is based on the `EStateM.Result` type
+It turns out that the `IO` monad you see in your `main` function is based on a `Result` type
 which is similar to the `Except` type but it has an additional return value. The `liftIO` function
 converts any `Except String α` into `IO α` by simply mapping the ok case of the `Except` to the
-`Result.ok` and the error case to the `Result.error`.
+`Result.ok` and the error case to the Result.error.
 
 ## Lifting ExceptT
 

doc/notation.md

@@ -7,7 +7,7 @@ overloading existing) prefix, infix, and postfix operators.
 infixl:65   " + " => HAdd.hAdd  -- left-associative
 infix:50    " = " => Eq         -- non-associative
 infixr:80   " ^ " => HPow.hPow  -- right-associative
-prefix:75  "-"   => Neg.neg
+prefix:100  "-"   => Neg.neg
 # set_option quotPrecheck false
 postfix:max "⁻¹"  => Inv.inv
 ```
@@ -26,7 +26,7 @@ can make this more precise by looking at what the commands above unfold to:
 notation:65 lhs:65 " + " rhs:66 => HAdd.hAdd lhs rhs
 notation:50 lhs:51 " = " rhs:51 => Eq lhs rhs
 notation:80 lhs:81 " ^ " rhs:80 => HPow.hPow lhs rhs
-notation:75 "-" arg:75 => Neg.neg arg
+notation:100 "-" arg:100 => Neg.neg arg
 # set_option quotPrecheck false
 notation:1024 arg:1024 "⁻¹" => Inv.inv arg  -- `max` is a shorthand for precedence 1024
 ```

doc/quickstart.md

@@ -1,18 +1,51 @@
 # Quickstart
 
-These instructions will walk you through setting up Lean 4 together with VS Code as an editor for Lean 4.
-See [Setup](./setup.md) for supported platforms and other ways to set up Lean 4.
+These instructions will walk you through setting up Lean using the "basic" setup and VS Code as the editor.
+See [Setup](./setup.md) for other ways, supported platforms, and more details on setting up Lean.
+
+See quick [walkthrough demo video](https://www.youtube.com/watch?v=yZo6k48L0VY).
 
 1. Install [VS Code](https://code.visualstudio.com/).
 
-1. Launch VS Code and install the `lean4` extension by clicking on the "Extensions" sidebar entry and searching for "lean4".
+1. Launch VS Code and install the `lean4` extension.
 
     ![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`), clicking on the ∀-symbol in the top right and selecting "Documentation… > Setup: Show Setup Guide".
+1. Create a new file using "File > New Text File" (`Ctrl+N`). Click the `Select a language` prompt, type in `lean4`, and hit ENTER.  You should see the following popup:
+    ![elan](images/install_elan.png)
 
-    ![show setup guide](images/show-setup-guide.png)
+    Click the "Install Lean using Elan" button. You should see some progress output like this:
 
-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.
+    ```
+    info: syncing channel updates for 'nightly'
+    info: latest update on nightly, lean version nightly-2021-12-05
+    info: downloading component 'lean'
+    ```
 
-    ![setup guide](images/setup_guide.png)
+1. While it is installing, you can paste the following Lean program into the new file:
+
+    ```lean
+    #eval Lean.versionString
+    ```
+
+    When the installation has finished, the Lean Language Server should start automatically and you should get syntax-highlighting and a "Lean Infoview" popping up on the right.  You will see the output of the `#eval` statement when
+    you place your cursor at the end of the statement.
+
+    ![successful setup](images/code-success.png)
+
+You are set up!
+
+## Create a Lean Project
+
+You can now create a Lean project in a new folder. Run `lake init foo` from "View > Terminal" to create a package, followed by `lake build` to get an executable version of your Lean program.
+On Linux/macOS, you first have to follow the instructions printed by the Lean installation or log out and in again for the Lean executables to be available in you terminal.
+
+Note: Packages **have** to be opened using "File > Open Folder..." for imports to work.
+Saved changes are visible in other files after running "Lean 4: Refresh File Dependencies" (`Ctrl+Shift+X`).
+
+## Troubleshooting
+
+**The InfoView says "Waiting for Lean server to start..." forever.**
+
+Check that the VS Code Terminal is not showing some installation errors from `elan`.
+If that doesn't work, try also running the VS Code command `Developer: Reload Window`.

doc/semantic_highlighting.md

@@ -1,23 +0,0 @@
-Semantic Highlighting
----------------------
-
-The Lean language server provides semantic highlighting information to editors. In order to benefit from this in VSCode, you may need to activate the "Editor > Semantic Highlighting" option in the preferences (this is translates to `"editor.semanticHighlighting.enabled": true,`
-in `settings.json`). The default option here is to let your color theme decides whether it activates semantic highlighting (the default themes Dark+ and Light+ do activate it for instance).
-
-However this may be insufficient if your color theme does not distinguish enough syntax categories or distinguishes them very subtly. For instance the default Light+ theme uses color `#001080` for variables. This is awfully close to `#000000` that is used as the default text color. This makes it very easy to miss an accidental use of [auto bound implicit arguments](https://lean-lang.org/lean4/doc/autobound.html). For instance in
-```lean
-def my_id (n : nat) := n
-```
-maybe `nat` is a typo and `Nat` was intended. If your color theme is good enough then you should see that `n` and `nat` have the same color since they are both marked as variables by semantic highlighting. If you rather write `(n : Nat)` then `n` keeps its variable color but `Nat` gets the default text color.
-
-If you use such a bad theme, you can fix things by modifying the `Semantic Token Color Customizations` configuration. This cannot be done directly in the preferences dialog but you can click on "Edit in settings.json" to directly edit the settings file. Beware that you must save this file (in the same way you save any file opened in VSCode) before seeing any effect in other tabs or VSCode windows.
-
-In the main config object, you can add something like
-```
-"editor.semanticTokenColorCustomizations": {
-        "[Default Light+]": {"rules": {"function": "#ff0000", "property": "#00ff00", "variable": "#ff00ff"}}
-    },
-```
-The colors in this example are not meant to be nice but to be easy to spot in your file when testing. Of course you need to replace `Default Light+` with the name of your theme, and you can customize several themes if you use several themes. VSCode will display small colored boxes next to the HTML color specifications. Hovering on top of a color specification opens a convenient color picker dialog.
-
-In order to understand what `function`, `property` and `variable` mean in the above example, the easiest path is to open a Lean file and ask VSCode about its classification of various bits of your file. Open the command palette with Ctrl-shift-p (or ⌘-shift-p on a Mac) and search for "Inspect Editor Tokens and Scopes" (typing the word "tokens" should be enough to see it). You can then click on any word in your file and look if there is a "semantic token type" line in the displayed information.

doc/setup.md

@@ -2,7 +2,7 @@
 
 ### Tier 1
 
-Platforms built & tested by our CI, available as binary releases via elan (see below)
+Platforms built & tested by our CI, available as nightly & stable releases via elan (see above)
 
 * x86-64 Linux with glibc 2.27+
 * x86-64 macOS 10.15+
@@ -10,15 +10,13 @@ Platforms built & tested by our CI, available as binary releases via elan (see b
 
 ### Tier 2
 
-Platforms cross-compiled but not tested by our CI, available as binary releases
+Platforms cross-compiled but not tested by our CI, available as nightly & stable releases
 
 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
+* aarch64 (M1) macOS
 
 <!--
 ### Tier 3
@@ -28,17 +26,28 @@ Platforms that are known to work from manual testing, but do not come with CI or
 
 # Setting Up Lean
 
-See also the [quickstart](./quickstart.md) instructions for a standard setup with VS Code as the editor.
+There are currently two ways to set up a Lean 4 development environment:
+
+* [basic setup](./setup.md#basic-setup) (Linux/macOS/Windows): uses [`elan`](https://github.com/leanprover/elan) + your preinstalled editor
+* [Nix setup](./setup.md#nix-setup) (Linux/macOS/WSL): uses the [Nix](https://nixos.org/nix/) package manager for installing all dependencies localized to your project
+
+See also the [quickstart](./quickstart.md) instructions for using the basic setup with VS Code as the editor.
+
+## Basic Setup
 
 Release builds for all supported platforms are available at <https://github.com/leanprover/lean4/releases>.
 Instead of downloading these and setting up the paths manually, however, it is recommended to use the Lean version manager [`elan`](https://github.com/leanprover/elan) instead:
 ```sh
 $ elan self update  # in case you haven't updated elan in a while
-# download & activate latest Lean 4 stable release (https://github.com/leanprover/lean4/releases)
+# download & activate latest Lean 4 release (https://github.com/leanprover/lean4/releases)
 $ elan default leanprover/lean4:stable
+# alternatively, use the latest nightly build (https://github.com/leanprover/lean4-nightly/releases)
+$ elan default leanprover/lean4:nightly
+# alternatively, activate Lean 4 in current directory only
+$ elan override set leanprover/lean4:stable
 ```
 
-## `lake`
+### `lake`
 
 Lean 4 comes with a package manager named `lake`.
 Use `lake init foo` to initialize a Lean package `foo` in the current directory, and `lake build` to typecheck and build it as well as all its dependencies. Use `lake help` to learn about further commands.
@@ -50,16 +59,88 @@ Foo.lean       # main file, import via `import Foo`
 Foo/
   A.lean       # further files, import via e.g. `import Foo.A`
   A/...        # further nesting
-.lake/         # `lake` build output directory
+build/         # `lake` build output directory
 ```
 
-After running `lake build` you will see a binary named `./.lake/build/bin/foo` and when you run it you should see the output:
+After running `lake build` you will see a binary named `./build/bin/foo` and when you run it you should see the output:
 ```
 Hello, world!
 ```
 
-## Editing
+### Editing
 
 Lean implements the [Language Server Protocol](https://microsoft.github.io/language-server-protocol/) that can be used for interactive development in [Emacs](https://github.com/leanprover/lean4-mode), [VS Code](https://github.com/leanprover-community/vscode-lean4), and possibly other editors.
 
 Changes must be saved to be visible in other files, which must then be invalidated using an editor command (see links above).
+
+## Nix Setup
+
+The alternative setup based on Nix provides a perfectly reproducible development environment for your project from the Lean version down to the editor and Lean extension.
+However, it is still experimental and subject to change; in particular, it is heavily based on an unreleased version of Nix enabling [Nix Flakes](https://www.tweag.io/blog/2020-05-25-flakes/). The setup has been tested on NixOS, other Linux distributions, and macOS.
+
+After installing (any version of) Nix (<https://nixos.org/download.html>), you can easily open a shell with the particular pre-release version of Nix needed by and tested with our setup (called the "Lean shell" from here on):
+```bash
+$ nix-shell https://github.com/leanprover/lean4/archive/master.tar.gz -A nix
+```
+While this shell is sufficient for executing the steps below, it is recommended to also set the following options in `/etc/nix/nix.conf` (`nix.extraOptions` in NixOS):
+```
+max-jobs = auto  # Allow building multiple derivations in parallel
+keep-outputs = true  # Do not garbage-collect build time-only dependencies (e.g. clang)
+# Allow fetching build results from the Lean Cachix cache
+trusted-substituters = https://lean4.cachix.org/
+trusted-public-keys = cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY= lean4.cachix.org-1:mawtxSxcaiWE24xCXXgh3qnvlTkyU7evRRnGeAhD4Wk=
+```
+On a multi-user installation of Nix (the default), you need to restart the Nix daemon afterwards:
+```bash
+sudo pkill nix-daemon
+```
+
+The [Cachix](https://cachix.org/) integration will magically beam any build steps already executed by the CI right onto your machine when calling Nix commands in the shell opened above.
+It can be set up analogously as a cache for your own project.
+
+Note: Your system Nix might print warnings about not knowing some of the settings used by the Lean shell Nix, which can be ignored.
+
+### Basic Commands
+
+From a Lean shell, run
+```bash
+$ nix flake new mypkg -t github:leanprover/lean4
+```
+to create a new Lean package in directory `mypkg` using the latest commit of Lean 4.
+Such packages follow the same directory layout as described in the basic setup above, except for a `lakefile.lean` replaced by a `flake.nix` file set up so you can run Nix commands on it, for example:
+```bash
+$ nix build  # build package and all dependencies
+$ nix build .#executable  # compile `main` definition into executable (after you've added one)
+$ nix run .#emacs-dev  # open a pinned version of Emacs with lean4-mode fully set up
+$ nix run .#emacs-dev MyPackage.lean  # arguments can be passed as well, e.g. the file to open
+$ nix run .#vscode-dev MyPackage.lean  # ditto, using VS Code
+```
+Note that if you rename `MyPackage.lean`, you also have to adjust the `name` attribute in `flake.nix` accordingly.
+Also note that if you turn the package into a Git repository, only tracked files will be visible to Nix.
+
+As in the basic setup, changes need to be saved to be visible in other files, which have then to be invalidated via an editor command.
+
+If you don't want to or cannot start the pinned editor from Nix, e.g. because you're running Lean inside WSL/a container/on a different machine, you can manually point your editor at the `lean` wrapper script the commands above use internally:
+```bash
+$ nix build .#lean-dev -o result-lean-dev
+```
+The resulting `./result-lean-dev/bin/lean` script essentially runs `nix run .#lean` in the current project's root directory when you open a Lean file or use the "refresh dependencies" command such that the correct Lean version for that project is executed.
+This includes selecting the correct stage of Lean (which it will compile on the fly, though without progress output) if you are [working on Lean itself](./make/nix.md#editor-integration).
+
+Package dependencies can be added as further input flakes and passed to the `deps` list of `buildLeanPackage`. Example: <https://github.com/Kha/testpkg2/blob/master/flake.nix#L5>
+
+For hacking, it can be useful to temporarily override an input with a local checkout/different version of a dependency:
+```bash
+$ nix build --override-input somedep path/to/somedep
+```
+
+On a build error, Nix will show the last 10 lines of the output by default. You can pass `-L` to `nix build` to show all lines, or pass the shown `*.drv` path to `nix log` to show the full log after the fact.
+
+Keeping all outputs ever built on a machine alive can accumulate to quite impressive amounts of disk space, so you might want to trigger the Nix GC when `/nix/store/` has grown too large:
+```bash
+nix-collect-garbage
+```
+This will remove everything not reachable from "GC roots" such as the `./result` symlink created by `nix build`.
+
+Note that the package information in `flake.nix` is currently completely independent from `lakefile.lean` used in the basic setup.
+Unifying the two formats is TBD.

doc/syntax_highlight_in_latex.md

@@ -67,9 +67,6 @@ 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

doc/tactics.md

@@ -224,7 +224,7 @@ example (n : Nat) : (binToChar n).isSome -> n = 0 ∨ n = 1 := by
   next => exact fun _ => Or.inr rfl
   next => intro h; cases h
 
-/- Hypotheses about previous cases can be accessed by assigning them a
+/- Hypotheses about previous cases can be accessesd by assigning them a
    name, like `ne_zero` below. Information about the matched term can also
    be preserved using the `generalizing` tactic: -/
 example (n : Nat) : (n = 0) -> (binToChar n = some '0') := by

doc/tour.md

@@ -15,7 +15,7 @@ The most fundamental pieces of any Lean program are functions organized into nam
 [Functions](./functions.md) perform work on inputs to produce outputs,
 and they are organized under [namespaces](./namespaces.md),
 which are the primary way you group things in Lean.
-They are defined using the `def` command,
+They are defined using the [`def`](./definitions.md) command,
 which give the function a name and define its arguments.
 
 ```lean

doc/tpil.md

@@ -1,5 +1,5 @@
 Theorem Proving in Lean
 =======================
 
-We strongly encourage you to read the book [Theorem Proving in Lean](https://lean-lang.org/theorem_proving_in_lean4/title_page.html).
+We strongly encourage you to read the book [Theorem Proving in Lean](https://leanprover.github.io/theorem_proving_in_lean4/title_page.html).
 Many Lean users consider it to be the Lean Bible.

doc/typeclass.md

@@ -99,11 +99,11 @@ Let us start with the first step of the program above, declaring an appropriate
 
 ```lean
 # namespace Ex
-class Inhabited (a : Sort u) where
+class Inhabited (a : Type u) where
   default : a
 
 #check @Inhabited.default
--- Inhabited.default : {a : Sort u} → [self : Inhabited a] → a
+-- Inhabited.default : {a : Type u} → [self : Inhabited a] → a
 # end Ex
 ```
 Note `Inhabited.default` doesn't have any explicit argument.
@@ -114,7 +114,7 @@ Now we populate the class with some instances:
 
 ```lean
 # namespace Ex
-# class Inhabited (a : Sort _) where
+# class Inhabited (a : Type _) where
 #  default : a
 instance : Inhabited Bool where
   default := true
@@ -138,7 +138,7 @@ instance : Inhabited Prop where
 You can use the command `export` to create the alias `default` for `Inhabited.default`
 ```lean
 # namespace Ex
-# class Inhabited (a : Sort _) where
+# class Inhabited (a : Type _) where
 #  default : a
 # instance : Inhabited Bool where
 #  default := true
@@ -174,7 +174,7 @@ instance [Inhabited a] [Inhabited b] : Inhabited (a × b) where
 With this added to the earlier instance declarations, type class instance can infer, for example, a default element of ``Nat × Bool``:
 ```lean
 # namespace Ex
-# class Inhabited (a : Sort u) where
+# class Inhabited (a : Type u) where
 #  default : a
 # instance : Inhabited Bool where
 #  default := true
@@ -191,14 +191,8 @@ instance [Inhabited a] [Inhabited b] : Inhabited (a × b) where
 ```
 Similarly, we can inhabit type function with suitable constant functions:
 ```lean
-# namespace Ex
-# class Inhabited (a : Sort u) where
-#  default : a
-# opaque default [Inhabited a] : a :=
-#  Inhabited.default
 instance [Inhabited b] : Inhabited (a -> b) where
   default := fun _ => default
-# end Ex
 ```
 As an exercise, try defining default instances for other types, such as `List` and `Sum` types.
 
@@ -388,7 +382,7 @@ class HMul (α : Type u) (β : Type v) (γ : outParam (Type w)) where
 
 export HMul (hMul)
 
-@[default_instance]
+@[defaultInstance]
 instance : HMul Int Int Int where
   hMul := Int.mul
 
@@ -397,7 +391,7 @@ def xs : List Int := [1, 2, 3]
 #check fun y => xs.map (fun x => hMul x y)  -- Int -> List Int
 # end Ex
 ```
-By tagging the instance above with the attribute `default_instance`, we are instructing Lean
+By tagging the instance above with the attribute `defaultInstance`, we are instructing Lean
 to use this instance on pending type class synthesis problems.
 The actual Lean implementation defines homogeneous and heterogeneous classes for arithmetical operators.
 Moreover, `a+b`, `a*b`, `a-b`, `a/b`, and `a%b` are notations for the heterogeneous versions.
@@ -410,7 +404,7 @@ structure Rational where
   den : Nat
   inv : den ≠ 0
 
-@[default_instance 200]
+@[defaultInstance 200]
 instance : OfNat Rational n where
   ofNat := { num := n, den := 1, inv := by decide }
 
@@ -429,7 +423,7 @@ Now, we reveal how the notation `a*b` is defined in Lean.
 class OfNat (α : Type u) (n : Nat) where
   ofNat : α
 
-@[default_instance]
+@[defaultInstance]
 instance (n : Nat) : OfNat Nat n where
   ofNat := n
 
@@ -439,7 +433,7 @@ class HMul (α : Type u) (β : Type v) (γ : outParam (Type w)) where
 class Mul (α : Type u) where
   mul : α → α → α
 
-@[default_instance 10]
+@[defaultInstance 10]
 instance [Mul α] : HMul α α α where
   hMul a b := Mul.mul a b