Bump 0.12.3 (#19279 )

Filter ruff_linter::VERSION out of SARIF output tests (#19280 )
Summary -- Fixes the test failures in #19279. This is the same variable used to construct the SARIF output: 350d563c88/crates/ruff_linter/src/message/sarif.rs (L39-L44) Test Plan -- Existing tests with the modified filter
2025-07-11 09:07:50 -04:00 · 2025-07-11 08:55:51 -04:00 · 2025-07-11 16:29:16 +05:30 · 2025-07-11 09:58:14 +02:00 · 2025-07-10 19:32:00 -07:00 · 2025-07-10 17:57:48 -04:00
356 changed files with 17927 additions and 4752 deletions
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -214,7 +214,7 @@ jobs:
      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
        with:
          persist-credentials: false
-      - uses: Swatinem/rust-cache@9d47c6ad4b02e050fd481d890b2ea34778fd09d6 # v2.7.8
+      - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
      - name: "Install Rust toolchain"
        run: |
          rustup component add clippy
@@ -234,17 +234,17 @@ jobs:
      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
        with:
          persist-credentials: false
-      - uses: Swatinem/rust-cache@9d47c6ad4b02e050fd481d890b2ea34778fd09d6 # v2.7.8
+      - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
      - name: "Install Rust toolchain"
        run: rustup show
      - name: "Install mold"
        uses: rui314/setup-mold@85c79d00377f0d32cdbae595a46de6f7c2fa6599 # v1
      - name: "Install cargo nextest"
-        uses: taiki-e/install-action@d12e869b89167df346dd0ff65da342d1fb1202fb # v2.53.2
+        uses: taiki-e/install-action@f3a27926ea13d7be3ee2f4cbb925883cf9442b56 # v2.56.7
        with:
          tool: cargo-nextest
      - name: "Install cargo insta"
-        uses: taiki-e/install-action@d12e869b89167df346dd0ff65da342d1fb1202fb # v2.53.2
+        uses: taiki-e/install-action@f3a27926ea13d7be3ee2f4cbb925883cf9442b56 # v2.56.7
        with:
          tool: cargo-insta
      - name: ty mdtests (GitHub annotations)
@@ -292,17 +292,17 @@ jobs:
      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
        with:
          persist-credentials: false
-      - uses: Swatinem/rust-cache@9d47c6ad4b02e050fd481d890b2ea34778fd09d6 # v2.7.8
+      - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
      - name: "Install Rust toolchain"
        run: rustup show
      - name: "Install mold"
        uses: rui314/setup-mold@85c79d00377f0d32cdbae595a46de6f7c2fa6599 # v1
      - name: "Install cargo nextest"
-        uses: taiki-e/install-action@d12e869b89167df346dd0ff65da342d1fb1202fb # v2.53.2
+        uses: taiki-e/install-action@f3a27926ea13d7be3ee2f4cbb925883cf9442b56 # v2.56.7
        with:
          tool: cargo-nextest
      - name: "Install cargo insta"
-        uses: taiki-e/install-action@d12e869b89167df346dd0ff65da342d1fb1202fb # v2.53.2
+        uses: taiki-e/install-action@f3a27926ea13d7be3ee2f4cbb925883cf9442b56 # v2.56.7
        with:
          tool: cargo-insta
      - name: "Run tests"
@@ -321,11 +321,11 @@ jobs:
      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
        with:
          persist-credentials: false
-      - uses: Swatinem/rust-cache@9d47c6ad4b02e050fd481d890b2ea34778fd09d6 # v2.7.8
+      - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
      - name: "Install Rust toolchain"
        run: rustup show
      - name: "Install cargo nextest"
-        uses: taiki-e/install-action@d12e869b89167df346dd0ff65da342d1fb1202fb # v2.53.2
+        uses: taiki-e/install-action@f3a27926ea13d7be3ee2f4cbb925883cf9442b56 # v2.56.7
        with:
          tool: cargo-nextest
      - name: "Run tests"
@@ -348,7 +348,7 @@ jobs:
      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
        with:
          persist-credentials: false
-      - uses: Swatinem/rust-cache@9d47c6ad4b02e050fd481d890b2ea34778fd09d6 # v2.7.8
+      - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
      - name: "Install Rust toolchain"
        run: rustup target add wasm32-unknown-unknown
      - uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4.4.0
@@ -377,7 +377,7 @@ jobs:
      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
        with:
          persist-credentials: false
-      - uses: Swatinem/rust-cache@9d47c6ad4b02e050fd481d890b2ea34778fd09d6 # v2.7.8
+      - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
      - name: "Install Rust toolchain"
        run: rustup show
      - name: "Install mold"
@@ -400,7 +400,7 @@ jobs:
        with:
          file: "Cargo.toml"
          field: "workspace.package.rust-version"
-      - uses: Swatinem/rust-cache@9d47c6ad4b02e050fd481d890b2ea34778fd09d6 # v2.7.8
+      - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
      - name: "Install Rust toolchain"
        env:
          MSRV: ${{ steps.msrv.outputs.value }}
@@ -408,11 +408,11 @@ jobs:
      - name: "Install mold"
        uses: rui314/setup-mold@85c79d00377f0d32cdbae595a46de6f7c2fa6599 # v1
      - name: "Install cargo nextest"
-        uses: taiki-e/install-action@d12e869b89167df346dd0ff65da342d1fb1202fb # v2.53.2
+        uses: taiki-e/install-action@f3a27926ea13d7be3ee2f4cbb925883cf9442b56 # v2.56.7
        with:
          tool: cargo-nextest
      - name: "Install cargo insta"
-        uses: taiki-e/install-action@d12e869b89167df346dd0ff65da342d1fb1202fb # v2.53.2
+        uses: taiki-e/install-action@f3a27926ea13d7be3ee2f4cbb925883cf9442b56 # v2.56.7
        with:
          tool: cargo-insta
      - name: "Run tests"
@@ -432,7 +432,7 @@ jobs:
      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
        with:
          persist-credentials: false
-      - uses: Swatinem/rust-cache@9d47c6ad4b02e050fd481d890b2ea34778fd09d6 # v2.7.8
+      - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
        with:
          workspaces: "fuzz -> target"
      - name: "Install Rust toolchain"
@@ -494,7 +494,7 @@ jobs:
      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
        with:
          persist-credentials: false
-      - uses: Swatinem/rust-cache@9d47c6ad4b02e050fd481d890b2ea34778fd09d6 # v2.7.8
+      - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
      - name: "Install Rust toolchain"
        run: rustup component add rustfmt
      # Run all code generation scripts, and verify that the current output is
@@ -708,7 +708,7 @@ jobs:
        with:
          python-version: ${{ env.PYTHON_VERSION }}
          architecture: x64
-      - uses: Swatinem/rust-cache@9d47c6ad4b02e050fd481d890b2ea34778fd09d6 # v2.7.8
+      - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
      - name: "Prep README.md"
        run: python scripts/transform_readme.py --target pypi
      - name: "Build wheels"
@@ -732,7 +732,7 @@ jobs:
        with:
          persist-credentials: false
      - uses: astral-sh/setup-uv@bd01e18f51369d5a26f1651c3cb451d3417e3bba # v6.3.1
-      - uses: Swatinem/rust-cache@9d47c6ad4b02e050fd481d890b2ea34778fd09d6 # v2.7.8
+      - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
      - uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4.4.0
        with:
          node-version: 22
@@ -765,7 +765,7 @@ jobs:
      - uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5.6.0
        with:
          python-version: "3.13"
-      - uses: Swatinem/rust-cache@9d47c6ad4b02e050fd481d890b2ea34778fd09d6 # v2.7.8
+      - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
      - name: "Add SSH key"
        if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS == 'true' }}
        uses: webfactory/ssh-agent@a6f90b1f127823b31d4d4a8d96047790581349bd # v0.9.1
@@ -804,7 +804,7 @@ jobs:
      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
        with:
          persist-credentials: false
-      - uses: Swatinem/rust-cache@9d47c6ad4b02e050fd481d890b2ea34778fd09d6 # v2.7.8
+      - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
      - name: "Install Rust toolchain"
        run: rustup show
      - name: "Run checks"
@@ -874,7 +874,7 @@ jobs:
          persist-credentials: false
      - name: "Install Rust toolchain"
        run: rustup target add wasm32-unknown-unknown
-      - uses: Swatinem/rust-cache@9d47c6ad4b02e050fd481d890b2ea34778fd09d6 # v2.7.8
+      - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
      - uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4.4.0
        with:
          node-version: 22
@@ -905,14 +905,14 @@ jobs:
        with:
          persist-credentials: false

-      - uses: Swatinem/rust-cache@9d47c6ad4b02e050fd481d890b2ea34778fd09d6 # v2.7.8
+      - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
      - uses: astral-sh/setup-uv@bd01e18f51369d5a26f1651c3cb451d3417e3bba # v6.3.1

      - name: "Install Rust toolchain"
        run: rustup show

      - name: "Install codspeed"
-        uses: taiki-e/install-action@d12e869b89167df346dd0ff65da342d1fb1202fb # v2.53.2
+        uses: taiki-e/install-action@f3a27926ea13d7be3ee2f4cbb925883cf9442b56 # v2.56.7
        with:
          tool: cargo-codspeed

@@ -938,14 +938,14 @@ jobs:
        with:
          persist-credentials: false

-      - uses: Swatinem/rust-cache@9d47c6ad4b02e050fd481d890b2ea34778fd09d6 # v2.7.8
+      - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
      - uses: astral-sh/setup-uv@bd01e18f51369d5a26f1651c3cb451d3417e3bba # v6.3.1

      - name: "Install Rust toolchain"
        run: rustup show

      - name: "Install codspeed"
-        uses: taiki-e/install-action@d12e869b89167df346dd0ff65da342d1fb1202fb # v2.53.2
+        uses: taiki-e/install-action@f3a27926ea13d7be3ee2f4cbb925883cf9442b56 # v2.56.7
        with:
          tool: cargo-codspeed

--- a/.github/workflows/daily_fuzz.yaml
+++ b/.github/workflows/daily_fuzz.yaml
@@ -39,7 +39,7 @@ jobs:
        run: rustup show
      - name: "Install mold"
        uses: rui314/setup-mold@85c79d00377f0d32cdbae595a46de6f7c2fa6599 # v1
-      - uses: Swatinem/rust-cache@9d47c6ad4b02e050fd481d890b2ea34778fd09d6 # v2.7.8
+      - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
      - name: Build ruff
        # A debug build means the script runs slower once it gets started,
        # but this is outweighed by the fact that a release build takes *much* longer to compile in CI
--- a/.github/workflows/mypy_primer.yaml
+++ b/.github/workflows/mypy_primer.yaml
@@ -12,6 +12,7 @@ on:
      - ".github/workflows/mypy_primer.yaml"
      - ".github/workflows/mypy_primer_comment.yaml"
      - "Cargo.lock"
+      - "!**.md"

 concurrency:
  group: ${{ github.workflow }}-${{ github.ref_name }}-${{ github.event.pull_request.number || github.sha }}
@@ -39,7 +40,7 @@ jobs:
      - name: Install the latest version of uv
        uses: astral-sh/setup-uv@bd01e18f51369d5a26f1651c3cb451d3417e3bba # v6.3.1

-      - uses: Swatinem/rust-cache@9d47c6ad4b02e050fd481d890b2ea34778fd09d6 # v2.7.8
+      - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
        with:
          workspaces: "ruff"

@@ -49,46 +50,12 @@ jobs:
      - name: Run mypy_primer
        shell: bash
        env:
-          TY_MEMORY_REPORT: mypy_primer
+          PRIMER_SELECTOR: crates/ty_python_semantic/resources/primer/good.txt
+          DIFF_FILE: mypy_primer.diff
        run: |
          cd ruff
-
-          echo "Enabling mypy primer specific configuration overloads (see .github/mypy-primer-ty.toml)"
-          mkdir -p ~/.config/ty
-          cp .github/mypy-primer-ty.toml ~/.config/ty/ty.toml
-
-          PRIMER_SELECTOR="$(paste -s -d'|' crates/ty_python_semantic/resources/primer/good.txt)"
-
-          echo "new commit"
-          git rev-list --format=%s --max-count=1 "$GITHUB_SHA"
-
-          MERGE_BASE="$(git merge-base "$GITHUB_SHA" "origin/$GITHUB_BASE_REF")"
-          git checkout -b base_commit "$MERGE_BASE"
-          echo "base commit"
-          git rev-list --format=%s --max-count=1 base_commit
-
-          cd ..
-
-          echo "Project selector: $PRIMER_SELECTOR"
-          # Allow the exit code to be 0 or 1, only fail for actual mypy_primer crashes/bugs
-          uvx \
-            --from="git+https://github.com/hauntsaninja/mypy_primer@e5f55447969d33ae3c7ccdb183e2a37101867270" \
-            mypy_primer \
-            --repo ruff \
-            --type-checker ty \
-            --old base_commit \
-            --new "$GITHUB_SHA" \
-            --project-selector "/($PRIMER_SELECTOR)\$" \
-            --output concise \
-            --debug > mypy_primer.diff || [ $? -eq 1 ]
-
-          # Output diff with ANSI color codes
-          cat mypy_primer.diff
-
-          # Remove ANSI color codes before uploading
-          sed -ie 's/\x1b\[[0-9;]*m//g' mypy_primer.diff
-
-          echo ${{ github.event.number }} > pr-number
+          scripts/mypy_primer.sh
+          echo ${{ github.event.number }} > ../pr-number

      - name: Upload diff
        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
@@ -101,3 +68,41 @@ jobs:
        with:
          name: pr-number
          path: pr-number
+
+  memory_usage:
+    name: Run memory statistics
+    runs-on: depot-ubuntu-22.04-32
+    timeout-minutes: 20
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        with:
+          path: ruff
+          fetch-depth: 0
+          persist-credentials: false
+
+      - name: Install the latest version of uv
+        uses: astral-sh/setup-uv@bd01e18f51369d5a26f1651c3cb451d3417e3bba # v6.3.1
+
+      - uses: Swatinem/rust-cache@9d47c6ad4b02e050fd481d890b2ea34778fd09d6 # v2.7.8
+        with:
+          workspaces: "ruff"
+
+      - name: Install Rust toolchain
+        run: rustup show
+
+      - name: Run mypy_primer
+        shell: bash
+        env:
+          TY_MAX_PARALLELISM: 1 # for deterministic memory numbers
+          TY_MEMORY_REPORT: mypy_primer
+          PRIMER_SELECTOR: crates/ty_python_semantic/resources/primer/memory.txt
+          DIFF_FILE: mypy_primer_memory.diff
+        run: |
+          cd ruff
+          scripts/mypy_primer.sh
+
+      - name: Upload diff
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
+        with:
+          name: mypy_primer_memory_diff
+          path: mypy_primer_memory.diff
--- a/.github/workflows/mypy_primer_comment.yaml
+++ b/.github/workflows/mypy_primer_comment.yaml
@@ -45,15 +45,28 @@ jobs:
          if_no_artifact_found: ignore
          allow_forks: true

+      - uses: dawidd6/action-download-artifact@20319c5641d495c8a52e688b7dc5fada6c3a9fbc # v8
+        name: "Download mypy_primer memory results"
+        id: download-mypy_primer_memory_diff
+        if: steps.pr-number.outputs.pr-number
+        with:
+          name: mypy_primer_memory_diff
+          workflow: mypy_primer.yaml
+          pr: ${{ steps.pr-number.outputs.pr-number }}
+          path: pr/mypy_primer_memory_diff
+          workflow_conclusion: completed
+          if_no_artifact_found: ignore
+          allow_forks: true
+
      - name: Generate comment content
        id: generate-comment
-        if: steps.download-mypy_primer_diff.outputs.found_artifact == 'true'
+        if: ${{ steps.download-mypy_primer_diff.outputs.found_artifact == 'true' && steps.download-mypy_primer_memory_diff.outputs.found_artifact == 'true' }}
        run: |
          # Guard against malicious mypy_primer results that symlink to a secret
          # file on this runner
-          if [[ -L pr/mypy_primer_diff/mypy_primer.diff ]]
+          if [[ -L pr/mypy_primer_diff/mypy_primer.diff ]] || [[ -L pr/mypy_primer_memory_diff/mypy_primer_memory.diff ]]
          then
-              echo "Error: mypy_primer.diff cannot be a symlink"
+              echo "Error: mypy_primer.diff and mypy_primer_memory.diff cannot be a symlink"
              exit 1
          fi

@@ -74,6 +87,18 @@ jobs:
            echo 'No ecosystem changes detected ✅' >> comment.txt
          fi

+          if [ -s "pr/mypy_primer_memory_diff/mypy_primer_memory.diff" ]; then
+            echo '<details>' >> comment.txt
+            echo '<summary>Memory usage changes were detected when running on open source projects</summary>' >> comment.txt
+            echo '' >> comment.txt
+            echo '```diff' >> comment.txt
+            cat pr/mypy_primer_memory_diff/mypy_primer_memory.diff >> comment.txt
+            echo '```' >> comment.txt
+            echo '</details>' >> comment.txt
+          else
+            echo 'No memory usage changes detected ✅' >> comment.txt
+          fi
+
          echo 'comment<<EOF' >> "$GITHUB_OUTPUT"
          cat comment.txt >> "$GITHUB_OUTPUT"
          echo 'EOF' >> "$GITHUB_OUTPUT"
--- a/.github/workflows/publish-docs.yml
+++ b/.github/workflows/publish-docs.yml
@@ -68,7 +68,7 @@ jobs:
      - name: "Install Rust toolchain"
        run: rustup show

-      - uses: Swatinem/rust-cache@9d47c6ad4b02e050fd481d890b2ea34778fd09d6 # v2.7.8
+      - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0

      - name: "Install Insiders dependencies"
        if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS == 'true' }}
--- a/.github/workflows/ty-ecosystem-analyzer.yaml
+++ b/.github/workflows/ty-ecosystem-analyzer.yaml
@@ -17,6 +17,7 @@ env:
  RUSTUP_MAX_RETRIES: 10
  RUST_BACKTRACE: 1
  REF_NAME: ${{ github.ref_name }}
+  CF_API_TOKEN_EXISTS: ${{ secrets.CF_API_TOKEN != '' }}

 jobs:
  ty-ecosystem-analyzer:
@@ -34,7 +35,7 @@ jobs:
      - name: Install the latest version of uv
        uses: astral-sh/setup-uv@bd01e18f51369d5a26f1651c3cb451d3417e3bba # v6.3.1

-      - uses: Swatinem/rust-cache@9d47c6ad4b02e050fd481d890b2ea34778fd09d6 # v2.7.8
+      - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
        with:
          workspaces: "ruff"

@@ -63,32 +64,75 @@ jobs:

          cd ..

-          uv tool install "git+https://github.com/astral-sh/ecosystem-analyzer@9c34dc514ee9aef6735db1dfebb80f63acbc3440"
+          uv tool install "git+https://github.com/astral-sh/ecosystem-analyzer@f0eec0e549684d8e1d7b8bc3e351202124b63bda"

          ecosystem-analyzer \
            --repository ruff \
-            analyze \
-            --projects ruff/projects_old.txt \
-            --commit old_commit \
-            --output diagnostics_old.json
+            diff \
+            --projects-old ruff/projects_old.txt \
+            --projects-new ruff/projects_new.txt \
+            --old old_commit \
+            --new new_commit \
+            --output-old diagnostics-old.json \
+            --output-new diagnostics-new.json

-          ecosystem-analyzer \
-            --repository ruff \
-            analyze \
-            --projects ruff/projects_new.txt \
-            --commit new_commit \
-            --output diagnostics_new.json
+          mkdir dist

          ecosystem-analyzer \
            generate-diff \
-            diagnostics_old.json \
-            diagnostics_new.json \
+            diagnostics-old.json \
+            diagnostics-new.json \
            --old-name "main (merge base)" \
            --new-name "$REF_NAME" \
-            --output-html diff.html
+            --output-html dist/diff.html

-      - name: Upload HTML diff report
+          ecosystem-analyzer \
+            generate-diff-statistics \
+            diagnostics-old.json \
+            diagnostics-new.json \
+            --old-name "main (merge base)" \
+            --new-name "$REF_NAME" \
+            --output diff-statistics.md
+
+          echo '## `ecosystem-analyzer` results' > comment.md
+          echo >> comment.md
+          cat diff-statistics.md >> comment.md
+
+          cat diff-statistics.md >> "$GITHUB_STEP_SUMMARY"
+
+          echo ${{ github.event.number }} > pr-number
+
+      - name: "Deploy to Cloudflare Pages"
+        if: ${{ env.CF_API_TOKEN_EXISTS == 'true' }}
+        id: deploy
+        uses: cloudflare/wrangler-action@da0e0dfe58b7a431659754fdf3f186c529afbe65 # v3.14.1
+        with:
+          apiToken: ${{ secrets.CF_API_TOKEN }}
+          accountId: ${{ secrets.CF_ACCOUNT_ID }}
+          command: pages deploy dist --project-name=ty-ecosystem --branch ${{ github.head_ref }} --commit-hash ${GITHUB_SHA}
+
+      - name: "Append deployment URL"
+        if: ${{ env.CF_API_TOKEN_EXISTS == 'true' }}
+        env:
+          DEPLOYMENT_URL: ${{ steps.deploy.outputs.pages-deployment-alias-url }}
+        run: |
+          echo >> comment.md
+          echo "**[Full report with detailed diff]($DEPLOYMENT_URL/diff)**" >> comment.md
+
+      - name: Upload comment
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
+        with:
+          name: comment.md
+          path: comment.md
+
+      - name: Upload pr-number
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
+        with:
+          name: pr-number
+          path: pr-number
+
+      - name: Upload diagnostics diff
        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
        with:
          name: diff.html
-          path: diff.html
+          path: dist/diff.html
--- a/.github/workflows/ty-ecosystem-analyzer_comment.yaml
+++ b/.github/workflows/ty-ecosystem-analyzer_comment.yaml
@@ -0,0 +1,85 @@
+name: PR comment (ty ecosystem-analyzer)
+
+on: # zizmor: ignore[dangerous-triggers]
+  workflow_run:
+    workflows: [ty ecosystem-analyzer]
+    types: [completed]
+  workflow_dispatch:
+    inputs:
+      workflow_run_id:
+        description: The ty ecosystem-analyzer workflow that triggers the workflow run
+        required: true
+
+jobs:
+  comment:
+    runs-on: ubuntu-24.04
+    permissions:
+      pull-requests: write
+    steps:
+      - uses: dawidd6/action-download-artifact@20319c5641d495c8a52e688b7dc5fada6c3a9fbc # v8
+        name: Download PR number
+        with:
+          name: pr-number
+          run_id: ${{ github.event.workflow_run.id ||  github.event.inputs.workflow_run_id }}
+          if_no_artifact_found: ignore
+          allow_forks: true
+
+      - name: Parse pull request number
+        id: pr-number
+        run: |
+          if [[ -f pr-number ]]
+          then
+            echo "pr-number=$(<pr-number)" >> "$GITHUB_OUTPUT"
+          fi
+
+      - uses: dawidd6/action-download-artifact@20319c5641d495c8a52e688b7dc5fada6c3a9fbc # v8
+        name: "Download comment.md"
+        id: download-comment
+        if: steps.pr-number.outputs.pr-number
+        with:
+          name: comment.md
+          workflow: ty-ecosystem-analyzer.yaml
+          pr: ${{ steps.pr-number.outputs.pr-number }}
+          path: pr/comment
+          workflow_conclusion: completed
+          if_no_artifact_found: ignore
+          allow_forks: true
+
+      - name: Generate comment content
+        id: generate-comment
+        if: ${{ steps.download-comment.outputs.found_artifact == 'true' }}
+        run: |
+          # Guard against malicious ty ecosystem-analyzer results that symlink to a secret
+          # file on this runner
+          if [[ -L pr/comment/comment.md ]]
+          then
+              echo "Error: comment.md cannot be a symlink"
+              exit 1
+          fi
+
+          # Note: this identifier is used to find the comment to update on subsequent runs
+          echo '<!-- generated-comment ty ecosystem-analyzer -->' > comment.md
+          echo >> comment.md
+          cat pr/comment/comment.md >> comment.md
+
+          echo 'comment<<EOF' >> "$GITHUB_OUTPUT"
+          cat comment.md >> "$GITHUB_OUTPUT"
+          echo 'EOF' >> "$GITHUB_OUTPUT"
+
+      - name: Find existing comment
+        uses: peter-evans/find-comment@3eae4d37986fb5a8592848f6a574fdf654e61f9e # v3.1.0
+        if: steps.generate-comment.outcome == 'success'
+        id: find-comment
+        with:
+          issue-number: ${{ steps.pr-number.outputs.pr-number }}
+          comment-author: "github-actions[bot]"
+          body-includes: "<!-- generated-comment ty ecosystem-analyzer -->"
+
+      - name: Create or update comment
+        if: steps.find-comment.outcome == 'success'
+        uses: peter-evans/create-or-update-comment@71345be0265236311c031f5c7866368bd1eff043 # v4
+        with:
+          comment-id: ${{ steps.find-comment.outputs.comment-id }}
+          issue-number: ${{ steps.pr-number.outputs.pr-number }}
+          body-path: comment.md
+          edit-mode: replace
--- a/.github/zizmor.yml
+++ b/.github/zizmor.yml
@@ -10,6 +10,7 @@ rules:
    ignore:
      - build-docker.yml
      - publish-playground.yml
+      - ty-ecosystem-analyzer.yaml
  excessive-permissions:
    # it's hard to test what the impact of removing these ignores would be
    # without actually running the release workflow...
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -6,7 +6,7 @@ exclude: |
    crates/ty_vendored/vendor/.*|
    crates/ty_project/resources/.*|
    crates/ty_python_semantic/resources/corpus/.*|
-    crates/ty/docs/(configuration|rules|cli).md|
+    crates/ty/docs/(configuration|rules|cli|environment).md|
    crates/ruff_benchmark/resources/.*|
    crates/ruff_linter/resources/.*|
    crates/ruff_linter/src/rules/.*/snapshots/.*|
@@ -67,7 +67,7 @@ repos:
          - black==25.1.0

  - repo: https://github.com/crate-ci/typos
-    rev: v1.33.1
+    rev: v1.34.0
    hooks:
      - id: typos

@@ -81,7 +81,7 @@ repos:
        pass_filenames: false # This makes it a lot faster

  - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.12.1
+    rev: v0.12.2
    hooks:
      - id: ruff-format
      - id: ruff
@@ -99,12 +99,12 @@ repos:
  # zizmor detects security vulnerabilities in GitHub Actions workflows.
  # Additional configuration for the tool is found in `.github/zizmor.yml`
  - repo: https://github.com/woodruffw/zizmor-pre-commit
-    rev: v1.10.0
+    rev: v1.11.0
    hooks:
      - id: zizmor

  - repo: https://github.com/python-jsonschema/check-jsonschema
-    rev: 0.33.1
+    rev: 0.33.2
    hooks:
      - id: check-github-workflows

--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,89 @@
 # Changelog

+## 0.12.3
+
+### Preview features
+
+- \[`flake8-bugbear`\] Support non-context-manager calls in `B017` ([#19063](https://github.com/astral-sh/ruff/pull/19063))
+- \[`flake8-use-pathlib`\] Add autofixes for `PTH100`, `PTH106`, `PTH107`, `PTH108`, `PTH110`, `PTH111`, `PTH112`, `PTH113`, `PTH114`, `PTH115`, `PTH117`, `PTH119`, `PTH120` ([#19213](https://github.com/astral-sh/ruff/pull/19213))
+- \[`flake8-use-pathlib`\] Add autofixes for `PTH203`, `PTH204`, `PTH205` ([#18922](https://github.com/astral-sh/ruff/pull/18922))
+
+### Bug fixes
+
+- \[`flake8-return`\] Fix false-positive for variables used inside nested functions in `RET504` ([#18433](https://github.com/astral-sh/ruff/pull/18433))
+- Treat form feed as valid whitespace before a line continuation ([#19220](https://github.com/astral-sh/ruff/pull/19220))
+- \[`flake8-type-checking`\] Fix syntax error introduced by fix (`TC008`) ([#19150](https://github.com/astral-sh/ruff/pull/19150))
+- \[`pyupgrade`\] Keyword arguments in `super` should suppress the `UP008` fix ([#19131](https://github.com/astral-sh/ruff/pull/19131))
+
+### Documentation
+
+- \[`flake8-pyi`\] Make example error out-of-the-box (`PYI007`, `PYI008`) ([#19103](https://github.com/astral-sh/ruff/pull/19103))
+- \[`flake8-simplify`\] Make example error out-of-the-box (`SIM116`) ([#19111](https://github.com/astral-sh/ruff/pull/19111))
+- \[`flake8-type-checking`\] Make example error out-of-the-box (`TC001`) ([#19151](https://github.com/astral-sh/ruff/pull/19151))
+- \[`flake8-use-pathlib`\] Make example error out-of-the-box (`PTH210`) ([#19189](https://github.com/astral-sh/ruff/pull/19189))
+- \[`pycodestyle`\] Make example error out-of-the-box (`E272`) ([#19191](https://github.com/astral-sh/ruff/pull/19191))
+- \[`pycodestyle`\] Make example not raise unnecessary `SyntaxError` (`E114`) ([#19190](https://github.com/astral-sh/ruff/pull/19190))
+- \[`pydoclint`\] Make example error out-of-the-box (`DOC501`) ([#19218](https://github.com/astral-sh/ruff/pull/19218))
+- \[`pylint`, `pyupgrade`\] Fix syntax errors in examples (`PLW1501`, `UP028`) ([#19127](https://github.com/astral-sh/ruff/pull/19127))
+- \[`pylint`\] Update `missing-maxsplit-arg` docs and error to suggest proper usage (`PLC0207`) ([#18949](https://github.com/astral-sh/ruff/pull/18949))
+- \[`flake8-bandit`\] Make example error out-of-the-box (`S412`) ([#19241](https://github.com/astral-sh/ruff/pull/19241))
+
+## 0.12.2
+
+### Preview features
+
+- \[`flake8-pyi`\] Expand `Optional[A]` to `A | None` (`PYI016`) ([#18572](https://github.com/astral-sh/ruff/pull/18572))
+- \[`pyupgrade`\] Mark `UP008` fix safe if no comments are in range ([#18683](https://github.com/astral-sh/ruff/pull/18683))
+
+### Bug fixes
+
+- \[`flake8-comprehensions`\] Fix `C420` to prepend whitespace when needed ([#18616](https://github.com/astral-sh/ruff/pull/18616))
+- \[`perflint`\] Fix `PERF403` panic on attribute or subscription loop variable ([#19042](https://github.com/astral-sh/ruff/pull/19042))
+- \[`pydocstyle`\] Fix `D413` infinite loop for parenthesized docstring ([#18930](https://github.com/astral-sh/ruff/pull/18930))
+- \[`pylint`\] Fix `PLW0108` autofix introducing a syntax error when the lambda's body contains an assignment expression ([#18678](https://github.com/astral-sh/ruff/pull/18678))
+- \[`refurb`\] Fix false positive on empty tuples (`FURB168`) ([#19058](https://github.com/astral-sh/ruff/pull/19058))
+- \[`ruff`\] Allow more `field` calls from `attrs` (`RUF009`) ([#19021](https://github.com/astral-sh/ruff/pull/19021))
+- \[`ruff`\] Fix syntax error introduced for an empty string followed by a u-prefixed string (`UP025`) ([#18899](https://github.com/astral-sh/ruff/pull/18899))
+
+### Rule changes
+
+- \[`flake8-executable`\] Allow `uvx` in shebang line (`EXE003`) ([#18967](https://github.com/astral-sh/ruff/pull/18967))
+- \[`pandas`\] Avoid flagging `PD002` if `pandas` is not imported ([#18963](https://github.com/astral-sh/ruff/pull/18963))
+- \[`pyupgrade`\] Avoid PEP-604 unions with `typing.NamedTuple` (`UP007`, `UP045`) ([#18682](https://github.com/astral-sh/ruff/pull/18682))
+
+### Documentation
+
+- Document link between `import-outside-top-level (PLC0415)` and `lint.flake8-tidy-imports.banned-module-level-imports` ([#18733](https://github.com/astral-sh/ruff/pull/18733))
+- Fix description of the `format.skip-magic-trailing-comma` example ([#19095](https://github.com/astral-sh/ruff/pull/19095))
+- \[`airflow`\] Make `AIR302` example error out-of-the-box ([#18988](https://github.com/astral-sh/ruff/pull/18988))
+- \[`airflow`\] Make `AIR312` example error out-of-the-box ([#18989](https://github.com/astral-sh/ruff/pull/18989))
+- \[`flake8-annotations`\] Make `ANN401` example error out-of-the-box ([#18974](https://github.com/astral-sh/ruff/pull/18974))
+- \[`flake8-async`\] Make `ASYNC100` example error out-of-the-box ([#18993](https://github.com/astral-sh/ruff/pull/18993))
+- \[`flake8-async`\] Make `ASYNC105` example error out-of-the-box ([#19002](https://github.com/astral-sh/ruff/pull/19002))
+- \[`flake8-async`\] Make `ASYNC110` example error out-of-the-box ([#18975](https://github.com/astral-sh/ruff/pull/18975))
+- \[`flake8-async`\] Make `ASYNC210` example error out-of-the-box ([#18977](https://github.com/astral-sh/ruff/pull/18977))
+- \[`flake8-async`\] Make `ASYNC220`, `ASYNC221`, and `ASYNC222` examples error out-of-the-box ([#18978](https://github.com/astral-sh/ruff/pull/18978))
+- \[`flake8-async`\] Make `ASYNC251` example error out-of-the-box ([#18990](https://github.com/astral-sh/ruff/pull/18990))
+- \[`flake8-bandit`\] Make `S201` example error out-of-the-box ([#19017](https://github.com/astral-sh/ruff/pull/19017))
+- \[`flake8-bandit`\] Make `S604` and `S609` examples error out-of-the-box ([#19049](https://github.com/astral-sh/ruff/pull/19049))
+- \[`flake8-bugbear`\] Make `B028` example error out-of-the-box ([#19054](https://github.com/astral-sh/ruff/pull/19054))
+- \[`flake8-bugbear`\] Make `B911` example error out-of-the-box ([#19051](https://github.com/astral-sh/ruff/pull/19051))
+- \[`flake8-datetimez`\] Make `DTZ011` example error out-of-the-box ([#19055](https://github.com/astral-sh/ruff/pull/19055))
+- \[`flake8-datetimez`\] Make `DTZ901` example error out-of-the-box ([#19056](https://github.com/astral-sh/ruff/pull/19056))
+- \[`flake8-pyi`\] Make `PYI032` example error out-of-the-box ([#19061](https://github.com/astral-sh/ruff/pull/19061))
+- \[`flake8-pyi`\] Make example error out-of-the-box (`PYI014`, `PYI015`) ([#19097](https://github.com/astral-sh/ruff/pull/19097))
+- \[`flake8-pyi`\] Make example error out-of-the-box (`PYI042`) ([#19101](https://github.com/astral-sh/ruff/pull/19101))
+- \[`flake8-pyi`\] Make example error out-of-the-box (`PYI059`) ([#19080](https://github.com/astral-sh/ruff/pull/19080))
+- \[`flake8-pyi`\] Make example error out-of-the-box (`PYI062`) ([#19079](https://github.com/astral-sh/ruff/pull/19079))
+- \[`flake8-pytest-style`\] Make example error out-of-the-box (`PT023`) ([#19104](https://github.com/astral-sh/ruff/pull/19104))
+- \[`flake8-pytest-style`\] Make example error out-of-the-box (`PT030`) ([#19105](https://github.com/astral-sh/ruff/pull/19105))
+- \[`flake8-quotes`\] Make example error out-of-the-box (`Q003`) ([#19106](https://github.com/astral-sh/ruff/pull/19106))
+- \[`flake8-simplify`\] Make example error out-of-the-box (`SIM110`) ([#19113](https://github.com/astral-sh/ruff/pull/19113))
+- \[`flake8-simplify`\] Make example error out-of-the-box (`SIM113`) ([#19109](https://github.com/astral-sh/ruff/pull/19109))
+- \[`flake8-simplify`\] Make example error out-of-the-box (`SIM401`) ([#19110](https://github.com/astral-sh/ruff/pull/19110))
+- \[`pyflakes`\] Fix backslash in docs (`F621`) ([#19098](https://github.com/astral-sh/ruff/pull/19098))
+- \[`pylint`\] Fix `PLC0415` example ([#18970](https://github.com/astral-sh/ruff/pull/18970))
+
 ## 0.12.1

 ### Preview features
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -591,7 +591,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "117725a109d387c937a1533ce01b450cbde6b88abceea8473c4d7a85853cda3c"
 dependencies = [
 "lazy_static",
- "windows-sys 0.59.0",
+ "windows-sys 0.52.0",
 ]

 [[package]]
@@ -600,7 +600,7 @@ version = "3.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fde0e0ec90c9dfb3b4b1a0891a7dcd0e2bffde2f7efed5fe7c9bb00e5bfb915e"
 dependencies = [
- "windows-sys 0.59.0",
+ "windows-sys 0.52.0",
 ]

 [[package]]
@@ -633,10 +633,22 @@ dependencies = [
 "encode_unicode",
 "libc",
 "once_cell",
- "unicode-width 0.2.1",
 "windows-sys 0.59.0",
 ]

+[[package]]
+name = "console"
+version = "0.16.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2e09ced7ebbccb63b4c65413d821f2e00ce54c5ca4514ddc6b3c892fdbcbc69d"
+dependencies = [
+ "encode_unicode",
+ "libc",
+ "once_cell",
+ "unicode-width 0.2.1",
+ "windows-sys 0.60.2",
+]
+
 [[package]]
 name = "console_error_panic_hook"
 version = "0.1.7"
@@ -668,11 +680,6 @@ name = "countme"
 version = "3.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7704b5fdd17b18ae31c4c1da5a2e0305a2bf17b5249300a9ee9ed7b72114c636"
-dependencies = [
- "dashmap 5.5.3",
- "once_cell",
- "rustc-hash 1.1.0",
-]

 [[package]]
 name = "cpufeatures"
@@ -840,19 +847,6 @@ dependencies = [
 "syn",
 ]

-[[package]]
-name = "dashmap"
-version = "5.5.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "978747c1d849a7d2ee5e8adc0159961c48fb7e5db2f06af6723b80123bb53856"
-dependencies = [
- "cfg-if",
- "hashbrown 0.14.5",
- "lock_api",
- "once_cell",
- "parking_lot_core",
-]
-
 [[package]]
 name = "dashmap"
 version = "6.1.0"
@@ -1019,7 +1013,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cea14ef9355e3beab063703aa9dab15afd25f0667c341310c1e5274bb1d0da18"
 dependencies = [
 "libc",
- "windows-sys 0.59.0",
+ "windows-sys 0.52.0",
 ]

 [[package]]
@@ -1481,14 +1475,14 @@ dependencies = [

 [[package]]
 name = "indicatif"
-version = "0.17.11"
+version = "0.18.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "183b3088984b400f4cfac3620d5e076c84da5364016b4f49473de574b2586235"
+checksum = "70a646d946d06bedbbc4cac4c218acf4bbf2d87757a784857025f4d447e4e1cd"
 dependencies = [
- "console",
- "number_prefix",
+ "console 0.16.0",
 "portable-atomic",
 "unicode-width 0.2.1",
+ "unit-prefix",
 "vt100",
 "web-time",
 ]
@@ -1525,7 +1519,7 @@ version = "1.43.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "154934ea70c58054b556dd430b99a98c2a7ff5309ac9891597e339b5c28f4371"
 dependencies = [
- "console",
+ "console 0.15.11",
 "globset",
 "once_cell",
 "pest",
@@ -1592,7 +1586,7 @@ checksum = "e04d7f318608d35d4b61ddd75cbdaee86b023ebe2bd5a66ee0915f0bf93095a9"
 dependencies = [
 "hermit-abi 0.5.1",
 "libc",
- "windows-sys 0.59.0",
+ "windows-sys 0.52.0",
 ]

 [[package]]
@@ -1656,7 +1650,7 @@ dependencies = [
 "portable-atomic",
 "portable-atomic-util",
 "serde",
- "windows-sys 0.59.0",
+ "windows-sys 0.52.0",
 ]

 [[package]]
@@ -2025,12 +2019,11 @@ checksum = "61807f77802ff30975e01f4f071c8ba10c022052f98b3294119f3e615d13e5be"

 [[package]]
 name = "notify"
-version = "8.0.0"
+version = "8.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2fee8403b3d66ac7b26aee6e40a897d85dc5ce26f44da36b8b73e987cc52e943"
+checksum = "3163f59cd3fa0e9ef8c32f242966a7b9994fd7378366099593e0e73077cd8c97"
 dependencies = [
 "bitflags 2.9.1",
- "filetime",
 "fsevent-sys",
 "inotify",
 "kqueue",
@@ -2039,7 +2032,7 @@ dependencies = [
 "mio",
 "notify-types",
 "walkdir",
- "windows-sys 0.59.0",
+ "windows-sys 0.60.2",
 ]

 [[package]]
@@ -2077,12 +2070,6 @@ dependencies = [
 "libc",
 ]

-[[package]]
-name = "number_prefix"
-version = "0.4.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "830b246a0e5f20af87141b25c173cd1b609bd7779a4617d6ec582abaf90870f3"
-
 [[package]]
 name = "once_cell"
 version = "1.21.3"
@@ -2166,7 +2153,7 @@ dependencies = [
 "libc",
 "redox_syscall",
 "smallvec",
- "windows-targets",
+ "windows-targets 0.52.6",
 ]

 [[package]]
@@ -2257,7 +2244,7 @@ dependencies = [
 "once_cell",
 "pep440_rs",
 "regex",
- "rustc-hash 2.1.1",
+ "rustc-hash",
 "serde",
 "smallvec",
 "thiserror 1.0.69",
@@ -2724,7 +2711,7 @@ dependencies = [

 [[package]]
 name = "ruff"
-version = "0.12.1"
+version = "0.12.3"
 dependencies = [
 "anyhow",
 "argfile",
@@ -2767,7 +2754,7 @@ dependencies = [
 "ruff_source_file",
 "ruff_text_size",
 "ruff_workspace",
- "rustc-hash 2.1.1",
+ "rustc-hash",
 "serde",
 "serde_json",
 "shellexpand",
@@ -2813,7 +2800,7 @@ dependencies = [
 "ruff_python_formatter",
 "ruff_python_parser",
 "ruff_python_trivia",
- "rustc-hash 2.1.1",
+ "rustc-hash",
 "serde",
 "serde_json",
 "tikv-jemallocator",
@@ -2842,7 +2829,7 @@ dependencies = [
 "arc-swap",
 "camino",
 "countme",
- "dashmap 6.1.0",
+ "dashmap",
 "dunce",
 "etcetera",
 "filetime",
@@ -2854,13 +2841,14 @@ dependencies = [
 "path-slash",
 "ruff_annotate_snippets",
 "ruff_cache",
+ "ruff_diagnostics",
 "ruff_notebook",
 "ruff_python_ast",
 "ruff_python_parser",
 "ruff_python_trivia",
 "ruff_source_file",
 "ruff_text_size",
- "rustc-hash 2.1.1",
+ "rustc-hash",
 "salsa",
 "schemars",
 "serde",
@@ -2868,6 +2856,7 @@ dependencies = [
 "thiserror 2.0.12",
 "tracing",
 "tracing-subscriber",
+ "ty_static",
 "web-time",
 "zip",
 ]
@@ -2911,6 +2900,7 @@ dependencies = [
 "tracing-subscriber",
 "ty",
 "ty_project",
+ "ty_static",
 "url",
 ]

@@ -2918,6 +2908,7 @@ dependencies = [
 name = "ruff_diagnostics"
 version = "0.0.0"
 dependencies = [
+ "get-size2",
 "is-macro",
 "ruff_text_size",
 "serde",
@@ -2931,7 +2922,7 @@ dependencies = [
 "ruff_cache",
 "ruff_macros",
 "ruff_text_size",
- "rustc-hash 2.1.1",
+ "rustc-hash",
 "schemars",
 "serde",
 "static_assertions",
@@ -2970,7 +2961,7 @@ dependencies = [

 [[package]]
 name = "ruff_linter"
-version = "0.12.1"
+version = "0.12.3"
 dependencies = [
 "aho-corasick",
 "anyhow",
@@ -3013,7 +3004,7 @@ dependencies = [
 "ruff_python_trivia",
 "ruff_source_file",
 "ruff_text_size",
- "rustc-hash 2.1.1",
+ "rustc-hash",
 "schemars",
 "serde",
 "serde_json",
@@ -3085,7 +3076,7 @@ dependencies = [
 "ruff_python_trivia",
 "ruff_source_file",
 "ruff_text_size",
- "rustc-hash 2.1.1",
+ "rustc-hash",
 "salsa",
 "schemars",
 "serde",
@@ -3135,7 +3126,7 @@ dependencies = [
 "ruff_python_trivia",
 "ruff_source_file",
 "ruff_text_size",
- "rustc-hash 2.1.1",
+ "rustc-hash",
 "salsa",
 "schemars",
 "serde",
@@ -3184,7 +3175,7 @@ dependencies = [
 "ruff_python_trivia",
 "ruff_source_file",
 "ruff_text_size",
- "rustc-hash 2.1.1",
+ "rustc-hash",
 "serde",
 "serde_json",
 "static_assertions",
@@ -3208,7 +3199,7 @@ dependencies = [
 "ruff_python_parser",
 "ruff_python_stdlib",
 "ruff_text_size",
- "rustc-hash 2.1.1",
+ "rustc-hash",
 "schemars",
 "serde",
 "smallvec",
@@ -3256,6 +3247,7 @@ dependencies = [
 "lsp-server",
 "lsp-types",
 "regex",
+ "ruff_db",
 "ruff_diagnostics",
 "ruff_formatter",
 "ruff_linter",
@@ -3268,7 +3260,7 @@ dependencies = [
 "ruff_source_file",
 "ruff_text_size",
 "ruff_workspace",
- "rustc-hash 2.1.1",
+ "rustc-hash",
 "serde",
 "serde_json",
 "shellexpand",
@@ -3302,7 +3294,7 @@ dependencies = [

 [[package]]
 name = "ruff_wasm"
-version = "0.12.1"
+version = "0.12.3"
 dependencies = [
 "console_error_panic_hook",
 "console_log",
@@ -3357,7 +3349,7 @@ dependencies = [
 "ruff_python_semantic",
 "ruff_python_stdlib",
 "ruff_source_file",
- "rustc-hash 2.1.1",
+ "rustc-hash",
 "schemars",
 "serde",
 "shellexpand",
@@ -3376,12 +3368,6 @@ dependencies = [
 "serde_derive",
 ]

-[[package]]
-name = "rustc-hash"
-version = "1.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "08d43f7aa6b08d49f382cde6a7982047c3426db949b1424bc4b7ec9ae12c6ce2"
-
 [[package]]
 name = "rustc-hash"
 version = "2.1.1"
@@ -3404,7 +3390,7 @@ dependencies = [
 "errno",
 "libc",
 "linux-raw-sys",
- "windows-sys 0.59.0",
+ "windows-sys 0.52.0",
 ]

 [[package]]
@@ -3436,7 +3422,7 @@ dependencies = [
 "parking_lot",
 "portable-atomic",
 "rayon",
- "rustc-hash 2.1.1",
+ "rustc-hash",
 "salsa-macro-rules",
 "salsa-macros",
 "smallvec",
@@ -3600,9 +3586,9 @@ dependencies = [

 [[package]]
 name = "serde_with"
-version = "3.12.0"
+version = "3.14.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d6b6f7f2fcb69f747921f79f3926bd1e203fce4fef62c268dd3abfb6d86029aa"
+checksum = "f2c45cd61fefa9db6f254525d46e392b852e0e61d9a1fd36e5bd183450a556d5"
 dependencies = [
 "serde",
 "serde_derive",
@@ -3611,9 +3597,9 @@ dependencies = [

 [[package]]
 name = "serde_with_macros"
-version = "3.12.0"
+version = "3.14.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8d00caa5193a3c8362ac2b73be6b9e768aa5a4b2f721d8f4b339600c3cb51f8e"
+checksum = "de90945e6565ce0d9a25098082ed4ee4002e047cb59892c318d66821e14bb30f"
 dependencies = [
 "darling",
 "proc-macro2",
@@ -3794,7 +3780,7 @@ dependencies = [
 "getrandom 0.3.3",
 "once_cell",
 "rustix",
- "windows-sys 0.59.0",
+ "windows-sys 0.52.0",
 ]

 [[package]]
@@ -4053,9 +4039,9 @@ dependencies = [

 [[package]]
 name = "tracing-core"
-version = "0.1.33"
+version = "0.1.34"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e672c95779cf947c5311f83787af4fa8fffd12fb27e4993211a84bdfd9610f9c"
+checksum = "b9d12581f227e93f094d3af2ae690a574abb8a2b9b7a96e7cfe9647b2b617678"
 dependencies = [
 "once_cell",
 "valuable",
@@ -4074,9 +4060,9 @@ dependencies = [

 [[package]]
 name = "tracing-indicatif"
-version = "0.3.9"
+version = "0.3.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8201ca430e0cd893ef978226fd3516c06d9c494181c8bf4e5b32e30ed4b40aa1"
+checksum = "8c714cc8fc46db04fcfddbd274c6ef59bebb1b435155984e7c6e89c3ce66f200"
 dependencies = [
 "indicatif",
 "tracing",
@@ -4134,7 +4120,6 @@ dependencies = [
 "clap",
 "clap_complete_command",
 "colored 3.0.0",
- "countme",
 "crossbeam",
 "ctrlc",
 "dunce",
@@ -4157,6 +4142,7 @@ dependencies = [
 "ty_project",
 "ty_python_semantic",
 "ty_server",
+ "ty_static",
 "wild",
 ]

@@ -4164,12 +4150,16 @@ dependencies = [
 name = "ty_ide"
 version = "0.0.0"
 dependencies = [
+ "bitflags 2.9.1",
 "insta",
+ "regex",
 "ruff_db",
 "ruff_python_ast",
 "ruff_python_parser",
+ "ruff_python_trivia",
+ "ruff_source_file",
 "ruff_text_size",
- "rustc-hash 2.1.1",
+ "rustc-hash",
 "salsa",
 "smallvec",
 "tracing",
@@ -4201,7 +4191,7 @@ dependencies = [
 "ruff_python_ast",
 "ruff_python_formatter",
 "ruff_text_size",
- "rustc-hash 2.1.1",
+ "rustc-hash",
 "salsa",
 "schemars",
 "serde",
@@ -4222,7 +4212,6 @@ dependencies = [
 "camino",
 "colored 3.0.0",
 "compact_str",
- "countme",
 "dir-test",
 "drop_bomb",
 "get-size2",
@@ -4246,7 +4235,7 @@ dependencies = [
 "ruff_python_trivia",
 "ruff_source_file",
 "ruff_text_size",
- "rustc-hash 2.1.1",
+ "rustc-hash",
 "salsa",
 "schemars",
 "serde",
@@ -4259,6 +4248,7 @@ dependencies = [
 "thiserror 2.0.12",
 "tracing",
 "ty_python_semantic",
+ "ty_static",
 "ty_test",
 "ty_vendored",
 ]
@@ -4277,7 +4267,7 @@ dependencies = [
 "ruff_notebook",
 "ruff_source_file",
 "ruff_text_size",
- "rustc-hash 2.1.1",
+ "rustc-hash",
 "salsa",
 "serde",
 "serde_json",
@@ -4290,6 +4280,13 @@ dependencies = [
 "ty_vendored",
 ]

+[[package]]
+name = "ty_static"
+version = "0.0.1"
+dependencies = [
+ "ruff_macros",
+]
+
 [[package]]
 name = "ty_test"
 version = "0.0.0"
@@ -4308,7 +4305,7 @@ dependencies = [
 "ruff_python_trivia",
 "ruff_source_file",
 "ruff_text_size",
- "rustc-hash 2.1.1",
+ "rustc-hash",
 "rustc-stable-hash",
 "salsa",
 "serde",
@@ -4318,6 +4315,7 @@ dependencies = [
 "toml",
 "tracing",
 "ty_python_semantic",
+ "ty_static",
 "ty_vendored",
 ]

@@ -4470,6 +4468,12 @@ dependencies = [
 "rand 0.8.5",
 ]

+[[package]]
+name = "unit-prefix"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "323402cff2dd658f39ca17c789b502021b3f18707c91cdf22e3838e1b4023817"
+
 [[package]]
 name = "unscanny"
 version = "0.1.0"
@@ -4802,7 +4806,7 @@ version = "0.1.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cf221c93e13a30d793f7645a0e7762c55d169dbb0a49671918a2319d289b10bb"
 dependencies = [
- "windows-sys 0.59.0",
+ "windows-sys 0.52.0",
 ]

 [[package]]
@@ -4876,7 +4880,7 @@ version = "0.52.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "282be5f36a8ce781fad8c8ae18fa3f9beff57ec1b52cb3de0789201425d9a33d"
 dependencies = [
- "windows-targets",
+ "windows-targets 0.52.6",
 ]

 [[package]]
@@ -4885,7 +4889,16 @@ version = "0.59.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1e38bc4d79ed67fd075bcc251a1c39b32a1776bbe92e5bef1f0bf1f8c531853b"
 dependencies = [
- "windows-targets",
+ "windows-targets 0.52.6",
+]
+
+[[package]]
+name = "windows-sys"
+version = "0.60.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f2f500e4d28234f72040990ec9d39e3a6b950f9f22d3dba18416c35882612bcb"
+dependencies = [
+ "windows-targets 0.53.2",
 ]

 [[package]]
@@ -4894,14 +4907,30 @@ version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9b724f72796e036ab90c1021d4780d4d3d648aca59e491e6b98e725b84e99973"
 dependencies = [
- "windows_aarch64_gnullvm",
- "windows_aarch64_msvc",
- "windows_i686_gnu",
- "windows_i686_gnullvm",
- "windows_i686_msvc",
- "windows_x86_64_gnu",
- "windows_x86_64_gnullvm",
- "windows_x86_64_msvc",
+ "windows_aarch64_gnullvm 0.52.6",
+ "windows_aarch64_msvc 0.52.6",
+ "windows_i686_gnu 0.52.6",
+ "windows_i686_gnullvm 0.52.6",
+ "windows_i686_msvc 0.52.6",
+ "windows_x86_64_gnu 0.52.6",
+ "windows_x86_64_gnullvm 0.52.6",
+ "windows_x86_64_msvc 0.52.6",
+]
+
+[[package]]
+name = "windows-targets"
+version = "0.53.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c66f69fcc9ce11da9966ddb31a40968cad001c5bedeb5c2b82ede4253ab48aef"
+dependencies = [
+ "windows_aarch64_gnullvm 0.53.0",
+ "windows_aarch64_msvc 0.53.0",
+ "windows_i686_gnu 0.53.0",
+ "windows_i686_gnullvm 0.53.0",
+ "windows_i686_msvc 0.53.0",
+ "windows_x86_64_gnu 0.53.0",
+ "windows_x86_64_gnullvm 0.53.0",
+ "windows_x86_64_msvc 0.53.0",
 ]

 [[package]]
@@ -4910,48 +4939,96 @@ version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "32a4622180e7a0ec044bb555404c800bc9fd9ec262ec147edd5989ccd0c02cd3"

+[[package]]
+name = "windows_aarch64_gnullvm"
+version = "0.53.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "86b8d5f90ddd19cb4a147a5fa63ca848db3df085e25fee3cc10b39b6eebae764"
+
 [[package]]
 name = "windows_aarch64_msvc"
 version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "09ec2a7bb152e2252b53fa7803150007879548bc709c039df7627cabbd05d469"

+[[package]]
+name = "windows_aarch64_msvc"
+version = "0.53.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c7651a1f62a11b8cbd5e0d42526e55f2c99886c77e007179efff86c2b137e66c"
+
 [[package]]
 name = "windows_i686_gnu"
 version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8e9b5ad5ab802e97eb8e295ac6720e509ee4c243f69d781394014ebfe8bbfa0b"

+[[package]]
+name = "windows_i686_gnu"
+version = "0.53.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c1dc67659d35f387f5f6c479dc4e28f1d4bb90ddd1a5d3da2e5d97b42d6272c3"
+
 [[package]]
 name = "windows_i686_gnullvm"
 version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0eee52d38c090b3caa76c563b86c3a4bd71ef1a819287c19d586d7334ae8ed66"

+[[package]]
+name = "windows_i686_gnullvm"
+version = "0.53.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9ce6ccbdedbf6d6354471319e781c0dfef054c81fbc7cf83f338a4296c0cae11"
+
 [[package]]
 name = "windows_i686_msvc"
 version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "240948bc05c5e7c6dabba28bf89d89ffce3e303022809e73deaefe4f6ec56c66"

+[[package]]
+name = "windows_i686_msvc"
+version = "0.53.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "581fee95406bb13382d2f65cd4a908ca7b1e4c2f1917f143ba16efe98a589b5d"
+
 [[package]]
 name = "windows_x86_64_gnu"
 version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "147a5c80aabfbf0c7d901cb5895d1de30ef2907eb21fbbab29ca94c5b08b1a78"

+[[package]]
+name = "windows_x86_64_gnu"
+version = "0.53.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2e55b5ac9ea33f2fc1716d1742db15574fd6fc8dadc51caab1c16a3d3b4190ba"
+
 [[package]]
 name = "windows_x86_64_gnullvm"
 version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "24d5b23dc417412679681396f2b49f3de8c1473deb516bd34410872eff51ed0d"

+[[package]]
+name = "windows_x86_64_gnullvm"
+version = "0.53.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0a6e035dd0599267ce1ee132e51c27dd29437f63325753051e71dd9e42406c57"
+
 [[package]]
 name = "windows_x86_64_msvc"
 version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "589f6da84c646204747d1270a2a5661ea66ed1cced2631d546fdfb155959f9ec"

+[[package]]
+name = "windows_x86_64_msvc"
+version = "0.53.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "271414315aff87387382ec3d271b52d7ae78726f5d44ac98b4f4030c91880486"
+
 [[package]]
 name = "winnow"
 version = "0.7.10"
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -44,6 +44,7 @@ ty_ide = { path = "crates/ty_ide" }
 ty_project = { path = "crates/ty_project", default-features = false }
 ty_python_semantic = { path = "crates/ty_python_semantic" }
 ty_server = { path = "crates/ty_server" }
+ty_static = { path = "crates/ty_static" }
 ty_test = { path = "crates/ty_test" }
 ty_vendored = { path = "crates/ty_vendored" }

@@ -83,7 +84,7 @@ get-size2 = { version = "0.5.0", features = [
    "derive",
    "smallvec",
    "hashbrown",
-    "compact-str"
+    "compact-str",
 ] }
 glob = { version = "0.3.1" }
 globset = { version = "0.4.14" }
@@ -98,7 +99,7 @@ ignore = { version = "0.4.22" }
 imara-diff = { version = "0.1.5" }
 imperative = { version = "1.0.4" }
 indexmap = { version = "2.6.0" }
-indicatif = { version = "0.17.8" }
+indicatif = { version = "0.18.0" }
 indoc = { version = "2.0.4" }
 insta = { version = "1.35.1" }
 insta-cmd = { version = "0.6.0" }
@@ -167,13 +168,13 @@ tikv-jemallocator = { version = "0.6.0" }
 toml = { version = "0.8.11" }
 tracing = { version = "0.1.40" }
 tracing-flame = { version = "0.2.0" }
-tracing-indicatif = { version = "0.3.6" }
+tracing-indicatif = { version = "0.3.11" }
 tracing-log = { version = "0.2.0" }
 tracing-subscriber = { version = "0.3.18", default-features = false, features = [
    "env-filter",
    "fmt",
    "ansi",
-    "smallvec"
+    "smallvec",
 ] }
 tryfn = { version = "0.2.1" }
 typed-arena = { version = "2.0.2" }
@@ -183,11 +184,7 @@ unicode-width = { version = "0.2.0" }
 unicode_names2 = { version = "1.2.2" }
 unicode-normalization = { version = "0.1.23" }
 url = { version = "2.5.0" }
-uuid = { version = "1.6.1", features = [
-    "v4",
-    "fast-rng",
-    "macro-diagnostics",
-] }
+uuid = { version = "1.6.1", features = ["v4", "fast-rng", "macro-diagnostics"] }
 walkdir = { version = "2.3.2" }
 wasm-bindgen = { version = "0.2.92" }
 wasm-bindgen-test = { version = "0.3.42" }
@@ -222,8 +219,8 @@ must_use_candidate = "allow"
 similar_names = "allow"
 single_match_else = "allow"
 too_many_lines = "allow"
-needless_continue = "allow"       # An explicit continue can be more readable, especially if the alternative is an empty block.
-unnecessary_debug_formatting = "allow"  # too many instances, the display also doesn't quote the path which is often desired in logs where we use them the most often.
+needless_continue = "allow" # An explicit continue can be more readable, especially if the alternative is an empty block.
+unnecessary_debug_formatting = "allow" # too many instances, the display also doesn't quote the path which is often desired in logs where we use them the most often.
 # Without the hashes we run into a `rustfmt` bug in some snapshot tests, see #13250
 needless_raw_string_hashes = "allow"
 # Disallowed restriction lints
--- a/README.md
+++ b/README.md
@@ -148,8 +148,8 @@ curl -LsSf https://astral.sh/ruff/install.sh | sh
 powershell -c "irm https://astral.sh/ruff/install.ps1 | iex"

 # For a specific version.
-curl -LsSf https://astral.sh/ruff/0.12.1/install.sh | sh
-powershell -c "irm https://astral.sh/ruff/0.12.1/install.ps1 | iex"
+curl -LsSf https://astral.sh/ruff/0.12.3/install.sh | sh
+powershell -c "irm https://astral.sh/ruff/0.12.3/install.ps1 | iex"
 ```

 You can also install Ruff via [Homebrew](https://formulae.brew.sh/formula/ruff), [Conda](https://anaconda.org/conda-forge/ruff),
@@ -182,7 +182,7 @@ Ruff can also be used as a [pre-commit](https://pre-commit.com/) hook via [`ruff
 ```yaml
 - repo: https://github.com/astral-sh/ruff-pre-commit
  # Ruff version.
-  rev: v0.12.1
+  rev: v0.12.3
  hooks:
    # Run the linter.
    - id: ruff-check
@@ -430,6 +430,7 @@ Ruff is used by a number of major open-source projects and companies, including:
 - [Babel](https://github.com/python-babel/babel)
 - Benchling ([Refac](https://github.com/benchling/refac))
 - [Bokeh](https://github.com/bokeh/bokeh)
+- Capital One ([datacompy](https://github.com/capitalone/datacompy))
 - CrowdCent ([NumerBlox](https://github.com/crowdcent/numerblox)) <!-- typos: ignore -->
 - [Cryptography (PyCA)](https://github.com/pyca/cryptography)
 - CERN ([Indico](https://getindico.io/))
@@ -506,6 +507,7 @@ Ruff is used by a number of major open-source projects and companies, including:
 - [Streamlit](https://github.com/streamlit/streamlit)
 - [The Algorithms](https://github.com/TheAlgorithms/Python)
 - [Vega-Altair](https://github.com/altair-viz/altair)
+- [Weblate](https://weblate.org/)
 - WordPress ([Openverse](https://github.com/WordPress/openverse))
 - [ZenML](https://github.com/zenml-io/zenml)
 - [Zulip](https://github.com/zulip/zulip)
--- a/crates/ruff/Cargo.toml
+++ b/crates/ruff/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "ruff"
-version = "0.12.1"
+version = "0.12.3"
 publish = true
 authors = { workspace = true }
 edition = { workspace = true }
--- a/crates/ruff/src/cache.rs
+++ b/crates/ruff/src/cache.rs
@@ -18,14 +18,15 @@ use rustc_hash::FxHashMap;
 use tempfile::NamedTempFile;

 use ruff_cache::{CacheKey, CacheKeyHasher};
+use ruff_db::diagnostic::Diagnostic;
 use ruff_diagnostics::Fix;
-use ruff_linter::message::OldDiagnostic;
+use ruff_linter::message::create_lint_diagnostic;
 use ruff_linter::package::PackageRoot;
 use ruff_linter::{VERSION, warn_user};
 use ruff_macros::CacheKey;
 use ruff_notebook::NotebookIndex;
 use ruff_source_file::SourceFileBuilder;
-use ruff_text_size::{Ranged, TextRange, TextSize};
+use ruff_text_size::{TextRange, TextSize};
 use ruff_workspace::Settings;
 use ruff_workspace::resolver::Resolver;

@@ -348,7 +349,7 @@ impl FileCache {
                lint.messages
                    .iter()
                    .map(|msg| {
-                        OldDiagnostic::lint(
+                        create_lint_diagnostic(
                            &msg.body,
                            msg.suggestion.as_ref(),
                            msg.range,
@@ -428,11 +429,11 @@ pub(crate) struct LintCacheData {

 impl LintCacheData {
    pub(crate) fn from_diagnostics(
-        diagnostics: &[OldDiagnostic],
+        diagnostics: &[Diagnostic],
        notebook_index: Option<NotebookIndex>,
    ) -> Self {
        let source = if let Some(msg) = diagnostics.first() {
-            msg.source_file().source_text().to_owned()
+            msg.expect_ruff_source_file().source_text().to_owned()
        } else {
            String::new() // No messages, no need to keep the source!
        };
@@ -446,16 +447,16 @@ impl LintCacheData {
            .map(|(rule, msg)| {
                // Make sure that all message use the same source file.
                assert_eq!(
-                    msg.source_file(),
-                    diagnostics.first().unwrap().source_file(),
+                    msg.expect_ruff_source_file(),
+                    diagnostics.first().unwrap().expect_ruff_source_file(),
                    "message uses a different source file"
                );
                CacheMessage {
                    rule,
                    body: msg.body().to_string(),
                    suggestion: msg.suggestion().map(ToString::to_string),
-                    range: msg.range(),
-                    parent: msg.parent,
+                    range: msg.expect_range(),
+                    parent: msg.parent(),
                    fix: msg.fix().cloned(),
                    noqa_offset: msg.noqa_offset(),
                }
@@ -608,12 +609,12 @@ mod tests {
    use anyhow::Result;
    use filetime::{FileTime, set_file_mtime};
    use itertools::Itertools;
-    use ruff_linter::settings::LinterSettings;
    use test_case::test_case;

    use ruff_cache::CACHE_DIR_NAME;
-    use ruff_linter::message::OldDiagnostic;
+    use ruff_db::diagnostic::Diagnostic;
    use ruff_linter::package::PackageRoot;
+    use ruff_linter::settings::LinterSettings;
    use ruff_linter::settings::flags;
    use ruff_linter::settings::types::UnsafeFixes;
    use ruff_python_ast::{PySourceType, PythonVersion};
@@ -680,7 +681,7 @@ mod tests {
                    UnsafeFixes::Enabled,
                )
                .unwrap();
-                if diagnostics.inner.iter().any(OldDiagnostic::is_syntax_error) {
+                if diagnostics.inner.iter().any(Diagnostic::is_invalid_syntax) {
                    parse_errors.push(path.clone());
                }
                paths.push(path);
--- a/crates/ruff/src/commands/check.rs
+++ b/crates/ruff/src/commands/check.rs
@@ -11,13 +11,13 @@ use log::{debug, error, warn};
 use rayon::prelude::*;
 use rustc_hash::FxHashMap;

+use ruff_db::diagnostic::Diagnostic;
 use ruff_db::panic::catch_unwind;
-use ruff_linter::OldDiagnostic;
 use ruff_linter::package::PackageRoot;
 use ruff_linter::registry::Rule;
 use ruff_linter::settings::types::UnsafeFixes;
 use ruff_linter::settings::{LinterSettings, flags};
-use ruff_linter::{IOError, fs, warn_user_once};
+use ruff_linter::{IOError, Violation, fs, warn_user_once};
 use ruff_source_file::SourceFileBuilder;
 use ruff_text_size::TextRange;
 use ruff_workspace::resolver::{
@@ -129,11 +129,7 @@ pub(crate) fn check(
                        SourceFileBuilder::new(path.to_string_lossy().as_ref(), "").finish();

                    Diagnostics::new(
-                        vec![OldDiagnostic::new(
-                            IOError { message },
-                            TextRange::default(),
-                            &dummy,
-                        )],
+                        vec![IOError { message }.into_diagnostic(TextRange::default(), &dummy)],
                        FxHashMap::default(),
                    )
                } else {
@@ -166,7 +162,9 @@ pub(crate) fn check(
            |a, b| (a.0 + b.0, a.1 + b.1),
        );

-    all_diagnostics.inner.sort();
+    all_diagnostics
+        .inner
+        .sort_by(Diagnostic::ruff_start_ordering);

    // Store the caches.
    caches.persist()?;
--- a/crates/ruff/src/commands/check_stdin.rs
+++ b/crates/ruff/src/commands/check_stdin.rs
@@ -1,6 +1,7 @@
 use std::path::Path;

 use anyhow::Result;
+use ruff_db::diagnostic::Diagnostic;
 use ruff_linter::package::PackageRoot;
 use ruff_linter::packaging;
 use ruff_linter::settings::flags;
@@ -52,6 +53,8 @@ pub(crate) fn check_stdin(
        noqa,
        fix_mode,
    )?;
-    diagnostics.inner.sort_unstable();
+    diagnostics
+        .inner
+        .sort_unstable_by(Diagnostic::ruff_start_ordering);
    Ok(diagnostics)
 }
--- a/crates/ruff/src/diagnostics.rs
+++ b/crates/ruff/src/diagnostics.rs
@@ -10,35 +10,35 @@ use std::path::Path;
 use anyhow::{Context, Result};
 use colored::Colorize;
 use log::{debug, warn};
-use rustc_hash::FxHashMap;
-
-use ruff_linter::OldDiagnostic;
+use ruff_db::diagnostic::Diagnostic;
 use ruff_linter::codes::Rule;
 use ruff_linter::linter::{FixTable, FixerResult, LinterResult, ParseSource, lint_fix, lint_only};
+use ruff_linter::message::create_syntax_error_diagnostic;
 use ruff_linter::package::PackageRoot;
 use ruff_linter::pyproject_toml::lint_pyproject_toml;
 use ruff_linter::settings::types::UnsafeFixes;
 use ruff_linter::settings::{LinterSettings, flags};
 use ruff_linter::source_kind::{SourceError, SourceKind};
-use ruff_linter::{IOError, fs};
+use ruff_linter::{IOError, Violation, fs};
 use ruff_notebook::{Notebook, NotebookError, NotebookIndex};
 use ruff_python_ast::{PySourceType, SourceType, TomlSourceType};
 use ruff_source_file::SourceFileBuilder;
 use ruff_text_size::TextRange;
 use ruff_workspace::Settings;
+use rustc_hash::FxHashMap;

 use crate::cache::{Cache, FileCacheKey, LintCacheData};

 #[derive(Debug, Default, PartialEq)]
 pub(crate) struct Diagnostics {
-    pub(crate) inner: Vec<OldDiagnostic>,
+    pub(crate) inner: Vec<Diagnostic>,
    pub(crate) fixed: FixMap,
    pub(crate) notebook_indexes: FxHashMap<String, NotebookIndex>,
 }

 impl Diagnostics {
    pub(crate) fn new(
-        diagnostics: Vec<OldDiagnostic>,
+        diagnostics: Vec<Diagnostic>,
        notebook_indexes: FxHashMap<String, NotebookIndex>,
    ) -> Self {
        Self {
@@ -62,13 +62,12 @@ impl Diagnostics {
                    let name = path.map_or_else(|| "-".into(), Path::to_string_lossy);
                    let source_file = SourceFileBuilder::new(name, "").finish();
                    Self::new(
-                        vec![OldDiagnostic::new(
+                        vec![
                            IOError {
                                message: err.to_string(),
-                            },
-                            TextRange::default(),
-                            &source_file,
-                        )],
+                            }
+                            .into_diagnostic(TextRange::default(), &source_file),
+                        ],
                        FxHashMap::default(),
                    )
                } else {
@@ -98,10 +97,10 @@ impl Diagnostics {
                let name = path.map_or_else(|| "-".into(), Path::to_string_lossy);
                let dummy = SourceFileBuilder::new(name, "").finish();
                Self::new(
-                    vec![OldDiagnostic::syntax_error(
+                    vec![create_syntax_error_diagnostic(
+                        dummy,
                        err,
                        TextRange::default(),
-                        dummy,
                    )],
                    FxHashMap::default(),
                )
--- a/crates/ruff/src/printer.rs
+++ b/crates/ruff/src/printer.rs
@@ -9,12 +9,13 @@ use itertools::{Itertools, iterate};
 use ruff_linter::linter::FixTable;
 use serde::Serialize;

+use ruff_db::diagnostic::{Diagnostic, SecondaryCode};
 use ruff_linter::fs::relativize_path;
 use ruff_linter::logging::LogLevel;
 use ruff_linter::message::{
    AzureEmitter, Emitter, EmitterContext, GithubEmitter, GitlabEmitter, GroupedEmitter,
-    JsonEmitter, JsonLinesEmitter, JunitEmitter, OldDiagnostic, PylintEmitter, RdjsonEmitter,
-    SarifEmitter, SecondaryCode, TextEmitter,
+    JsonEmitter, JsonLinesEmitter, JunitEmitter, PylintEmitter, RdjsonEmitter, SarifEmitter,
+    TextEmitter,
 };
 use ruff_linter::notify_user;
 use ruff_linter::settings::flags::{self};
@@ -306,8 +307,7 @@ impl Printer {
            .sorted_by_key(|(code, message)| (*code, message.fixable()))
            .fold(
                vec![],
-                |mut acc: Vec<((Option<&SecondaryCode>, &OldDiagnostic), usize)>,
-                 (code, message)| {
+                |mut acc: Vec<((Option<&SecondaryCode>, &Diagnostic), usize)>, (code, message)| {
                    if let Some(((prev_code, _prev_message), count)) = acc.last_mut() {
                        if *prev_code == code {
                            *count += 1;
--- a/crates/ruff/tests/integration_test.rs
+++ b/crates/ruff/tests/integration_test.rs
@@ -1067,7 +1067,7 @@ fn show_statistics_syntax_errors() {
    success: false
    exit_code: 1
    ----- stdout -----
-    1		syntax-error
+    1		invalid-syntax
    Found 1 error.

    ----- stderr -----
@@ -1080,7 +1080,7 @@ fn show_statistics_syntax_errors() {
    success: false
    exit_code: 1
    ----- stdout -----
-    1		syntax-error
+    1		invalid-syntax
    Found 1 error.

    ----- stderr -----
@@ -1093,7 +1093,7 @@ fn show_statistics_syntax_errors() {
    success: false
    exit_code: 1
    ----- stdout -----
-    1		syntax-error
+    1		invalid-syntax
    Found 1 error.

    ----- stderr -----
--- a/crates/ruff/tests/lint.rs
+++ b/crates/ruff/tests/lint.rs
@@ -5692,3 +5692,57 @@ class Foo:
    "
    );
 }
+
+#[test_case::test_case("concise")]
+#[test_case::test_case("full")]
+#[test_case::test_case("json")]
+#[test_case::test_case("json-lines")]
+#[test_case::test_case("junit")]
+#[test_case::test_case("grouped")]
+#[test_case::test_case("github")]
+#[test_case::test_case("gitlab")]
+#[test_case::test_case("pylint")]
+#[test_case::test_case("rdjson")]
+#[test_case::test_case("azure")]
+#[test_case::test_case("sarif")]
+fn output_format(output_format: &str) -> Result<()> {
+    const CONTENT: &str = "\
+import os  # F401
+x = y      # F821
+match 42:  # invalid-syntax
+    case _: ...
+";
+
+    let tempdir = TempDir::new()?;
+    let input = tempdir.path().join("input.py");
+    fs::write(&input, CONTENT)?;
+
+    let snapshot = format!("output_format_{output_format}");
+
+    insta::with_settings!({
+        filters => vec![
+            (tempdir_filter(&tempdir).as_str(), "[TMP]/"),
+            (r#""[^"]+\\?/?input.py"#, r#""[TMP]/input.py"#),
+            (ruff_linter::VERSION, "[VERSION]"),
+        ]
+    }, {
+        assert_cmd_snapshot!(
+            snapshot,
+            Command::new(get_cargo_bin(BIN_NAME))
+                .args([
+                    "check",
+                    "--no-cache",
+                    "--output-format",
+                    output_format,
+                    "--select",
+                    "F401,F821",
+                    "--target-version",
+                    "py39",
+                    "input.py",
+                ])
+                .current_dir(&tempdir),
+        );
+    });
+
+    Ok(())
+}
--- a/crates/ruff/tests/snapshots/lint__output_format_azure.snap
+++ b/crates/ruff/tests/snapshots/lint__output_format_azure.snap
@@ -0,0 +1,23 @@
+---
+source: crates/ruff/tests/lint.rs
+info:
+  program: ruff
+  args:
+    - check
+    - "--no-cache"
+    - "--output-format"
+    - azure
+    - "--select"
+    - "F401,F821"
+    - "--target-version"
+    - py39
+    - input.py
+---
+success: false
+exit_code: 1
+----- stdout -----
+##vso[task.logissue type=error;sourcepath=[TMP]/input.py;linenumber=1;columnnumber=8;code=F401;]`os` imported but unused
+##vso[task.logissue type=error;sourcepath=[TMP]/input.py;linenumber=2;columnnumber=5;code=F821;]Undefined name `y`
+##vso[task.logissue type=error;sourcepath=[TMP]/input.py;linenumber=3;columnnumber=1;]SyntaxError: Cannot use `match` statement on Python 3.9 (syntax was added in Python 3.10)
+
+----- stderr -----
--- a/crates/ruff/tests/snapshots/lint__output_format_concise.snap
+++ b/crates/ruff/tests/snapshots/lint__output_format_concise.snap
@@ -0,0 +1,25 @@
+---
+source: crates/ruff/tests/lint.rs
+info:
+  program: ruff
+  args:
+    - check
+    - "--no-cache"
+    - "--output-format"
+    - concise
+    - "--select"
+    - "F401,F821"
+    - "--target-version"
+    - py39
+    - input.py
+---
+success: false
+exit_code: 1
+----- stdout -----
+input.py:1:8: F401 [*] `os` imported but unused
+input.py:2:5: F821 Undefined name `y`
+input.py:3:1: SyntaxError: Cannot use `match` statement on Python 3.9 (syntax was added in Python 3.10)
+Found 3 errors.
+[*] 1 fixable with the `--fix` option.
+
+----- stderr -----
--- a/crates/ruff/tests/snapshots/lint__output_format_full.snap
+++ b/crates/ruff/tests/snapshots/lint__output_format_full.snap
@@ -0,0 +1,49 @@
+---
+source: crates/ruff/tests/lint.rs
+info:
+  program: ruff
+  args:
+    - check
+    - "--no-cache"
+    - "--output-format"
+    - full
+    - "--select"
+    - "F401,F821"
+    - "--target-version"
+    - py39
+    - input.py
+---
+success: false
+exit_code: 1
+----- stdout -----
+input.py:1:8: F401 [*] `os` imported but unused
+  |
+1 | import os  # F401
+  |        ^^ F401
+2 | x = y      # F821
+3 | match 42:  # invalid-syntax
+  |
+  = help: Remove unused import: `os`
+
+input.py:2:5: F821 Undefined name `y`
+  |
+1 | import os  # F401
+2 | x = y      # F821
+  |     ^ F821
+3 | match 42:  # invalid-syntax
+4 |     case _: ...
+  |
+
+input.py:3:1: SyntaxError: Cannot use `match` statement on Python 3.9 (syntax was added in Python 3.10)
+  |
+1 | import os  # F401
+2 | x = y      # F821
+3 | match 42:  # invalid-syntax
+  | ^^^^^
+4 |     case _: ...
+  |
+
+Found 3 errors.
+[*] 1 fixable with the `--fix` option.
+
+----- stderr -----
--- a/crates/ruff/tests/snapshots/lint__output_format_github.snap
+++ b/crates/ruff/tests/snapshots/lint__output_format_github.snap
@@ -0,0 +1,23 @@
+---
+source: crates/ruff/tests/lint.rs
+info:
+  program: ruff
+  args:
+    - check
+    - "--no-cache"
+    - "--output-format"
+    - github
+    - "--select"
+    - "F401,F821"
+    - "--target-version"
+    - py39
+    - input.py
+---
+success: false
+exit_code: 1
+----- stdout -----
+::error title=Ruff (F401),file=[TMP]/input.py,line=1,col=8,endLine=1,endColumn=10::input.py:1:8: F401 `os` imported but unused
+::error title=Ruff (F821),file=[TMP]/input.py,line=2,col=5,endLine=2,endColumn=6::input.py:2:5: F821 Undefined name `y`
+::error title=Ruff,file=[TMP]/input.py,line=3,col=1,endLine=3,endColumn=6::input.py:3:1: SyntaxError: Cannot use `match` statement on Python 3.9 (syntax was added in Python 3.10)
+
+----- stderr -----
--- a/crates/ruff/tests/snapshots/lint__output_format_gitlab.snap
+++ b/crates/ruff/tests/snapshots/lint__output_format_gitlab.snap
@@ -0,0 +1,60 @@
+---
+source: crates/ruff/tests/lint.rs
+info:
+  program: ruff
+  args:
+    - check
+    - "--no-cache"
+    - "--output-format"
+    - gitlab
+    - "--select"
+    - "F401,F821"
+    - "--target-version"
+    - py39
+    - input.py
+---
+success: false
+exit_code: 1
+----- stdout -----
+[
+  {
+    "check_name": "F401",
+    "description": "`os` imported but unused",
+    "fingerprint": "4dbad37161e65c72",
+    "location": {
+      "lines": {
+        "begin": 1,
+        "end": 1
+      },
+      "path": "input.py"
+    },
+    "severity": "major"
+  },
+  {
+    "check_name": "F821",
+    "description": "Undefined name `y`",
+    "fingerprint": "7af59862a085230",
+    "location": {
+      "lines": {
+        "begin": 2,
+        "end": 2
+      },
+      "path": "input.py"
+    },
+    "severity": "major"
+  },
+  {
+    "check_name": "syntax-error",
+    "description": "Cannot use `match` statement on Python 3.9 (syntax was added in Python 3.10)",
+    "fingerprint": "e558cec859bb66e8",
+    "location": {
+      "lines": {
+        "begin": 3,
+        "end": 3
+      },
+      "path": "input.py"
+    },
+    "severity": "major"
+  }
+]
+----- stderr -----
--- a/crates/ruff/tests/snapshots/lint__output_format_grouped.snap
+++ b/crates/ruff/tests/snapshots/lint__output_format_grouped.snap
@@ -0,0 +1,27 @@
+---
+source: crates/ruff/tests/lint.rs
+info:
+  program: ruff
+  args:
+    - check
+    - "--no-cache"
+    - "--output-format"
+    - grouped
+    - "--select"
+    - "F401,F821"
+    - "--target-version"
+    - py39
+    - input.py
+---
+success: false
+exit_code: 1
+----- stdout -----
+input.py:
+  1:8 F401 [*] `os` imported but unused
+  2:5 F821 Undefined name `y`
+  3:1 SyntaxError: Cannot use `match` statement on Python 3.9 (syntax was added in Python 3.10)
+
+Found 3 errors.
+[*] 1 fixable with the `--fix` option.
+
+----- stderr -----
--- a/crates/ruff/tests/snapshots/lint__output_format_json-lines.snap
+++ b/crates/ruff/tests/snapshots/lint__output_format_json-lines.snap
@@ -0,0 +1,23 @@
+---
+source: crates/ruff/tests/lint.rs
+info:
+  program: ruff
+  args:
+    - check
+    - "--no-cache"
+    - "--output-format"
+    - json-lines
+    - "--select"
+    - "F401,F821"
+    - "--target-version"
+    - py39
+    - input.py
+---
+success: false
+exit_code: 1
+----- stdout -----
+{"cell":null,"code":"F401","end_location":{"column":10,"row":1},"filename":"[TMP]/input.py","fix":{"applicability":"safe","edits":[{"content":"","end_location":{"column":1,"row":2},"location":{"column":1,"row":1}}],"message":"Remove unused import: `os`"},"location":{"column":8,"row":1},"message":"`os` imported but unused","noqa_row":1,"url":"https://docs.astral.sh/ruff/rules/unused-import"}
+{"cell":null,"code":"F821","end_location":{"column":6,"row":2},"filename":"[TMP]/input.py","fix":null,"location":{"column":5,"row":2},"message":"Undefined name `y`","noqa_row":2,"url":"https://docs.astral.sh/ruff/rules/undefined-name"}
+{"cell":null,"code":null,"end_location":{"column":6,"row":3},"filename":"[TMP]/input.py","fix":null,"location":{"column":1,"row":3},"message":"SyntaxError: Cannot use `match` statement on Python 3.9 (syntax was added in Python 3.10)","noqa_row":null,"url":null}
+
+----- stderr -----
--- a/crates/ruff/tests/snapshots/lint__output_format_json.snap
+++ b/crates/ruff/tests/snapshots/lint__output_format_json.snap
@@ -0,0 +1,88 @@
+---
+source: crates/ruff/tests/lint.rs
+info:
+  program: ruff
+  args:
+    - check
+    - "--no-cache"
+    - "--output-format"
+    - json
+    - "--select"
+    - "F401,F821"
+    - "--target-version"
+    - py39
+    - input.py
+---
+success: false
+exit_code: 1
+----- stdout -----
+[
+  {
+    "cell": null,
+    "code": "F401",
+    "end_location": {
+      "column": 10,
+      "row": 1
+    },
+    "filename": "[TMP]/input.py",
+    "fix": {
+      "applicability": "safe",
+      "edits": [
+        {
+          "content": "",
+          "end_location": {
+            "column": 1,
+            "row": 2
+          },
+          "location": {
+            "column": 1,
+            "row": 1
+          }
+        }
+      ],
+      "message": "Remove unused import: `os`"
+    },
+    "location": {
+      "column": 8,
+      "row": 1
+    },
+    "message": "`os` imported but unused",
+    "noqa_row": 1,
+    "url": "https://docs.astral.sh/ruff/rules/unused-import"
+  },
+  {
+    "cell": null,
+    "code": "F821",
+    "end_location": {
+      "column": 6,
+      "row": 2
+    },
+    "filename": "[TMP]/input.py",
+    "fix": null,
+    "location": {
+      "column": 5,
+      "row": 2
+    },
+    "message": "Undefined name `y`",
+    "noqa_row": 2,
+    "url": "https://docs.astral.sh/ruff/rules/undefined-name"
+  },
+  {
+    "cell": null,
+    "code": null,
+    "end_location": {
+      "column": 6,
+      "row": 3
+    },
+    "filename": "[TMP]/input.py",
+    "fix": null,
+    "location": {
+      "column": 1,
+      "row": 3
+    },
+    "message": "SyntaxError: Cannot use `match` statement on Python 3.9 (syntax was added in Python 3.10)",
+    "noqa_row": null,
+    "url": null
+  }
+]
+----- stderr -----
--- a/crates/ruff/tests/snapshots/lint__output_format_junit.snap
+++ b/crates/ruff/tests/snapshots/lint__output_format_junit.snap
@@ -0,0 +1,34 @@
+---
+source: crates/ruff/tests/lint.rs
+info:
+  program: ruff
+  args:
+    - check
+    - "--no-cache"
+    - "--output-format"
+    - junit
+    - "--select"
+    - "F401,F821"
+    - "--target-version"
+    - py39
+    - input.py
+---
+success: false
+exit_code: 1
+----- stdout -----
+<?xml version="1.0" encoding="UTF-8"?>
+<testsuites name="ruff" tests="3" failures="3" errors="0">
+    <testsuite name="[TMP]/input.py" tests="3" disabled="0" errors="0" failures="3" package="org.ruff">
+        <testcase name="org.ruff.F401" classname="[TMP]/input" line="1" column="8">
+            <failure message="`os` imported but unused">line 1, col 8, `os` imported but unused</failure>
+        </testcase>
+        <testcase name="org.ruff.F821" classname="[TMP]/input" line="2" column="5">
+            <failure message="Undefined name `y`">line 2, col 5, Undefined name `y`</failure>
+        </testcase>
+        <testcase name="org.ruff" classname="[TMP]/input" line="3" column="1">
+            <failure message="SyntaxError: Cannot use `match` statement on Python 3.9 (syntax was added in Python 3.10)">line 3, col 1, SyntaxError: Cannot use `match` statement on Python 3.9 (syntax was added in Python 3.10)</failure>
+        </testcase>
+    </testsuite>
+</testsuites>
+
+----- stderr -----
--- a/crates/ruff/tests/snapshots/lint__output_format_pylint.snap
+++ b/crates/ruff/tests/snapshots/lint__output_format_pylint.snap
@@ -0,0 +1,23 @@
+---
+source: crates/ruff/tests/lint.rs
+info:
+  program: ruff
+  args:
+    - check
+    - "--no-cache"
+    - "--output-format"
+    - pylint
+    - "--select"
+    - "F401,F821"
+    - "--target-version"
+    - py39
+    - input.py
+---
+success: false
+exit_code: 1
+----- stdout -----
+input.py:1: [F401] `os` imported but unused
+input.py:2: [F821] Undefined name `y`
+input.py:3: SyntaxError: Cannot use `match` statement on Python 3.9 (syntax was added in Python 3.10)
+
+----- stderr -----
--- a/crates/ruff/tests/snapshots/lint__output_format_rdjson.snap
+++ b/crates/ruff/tests/snapshots/lint__output_format_rdjson.snap
@@ -0,0 +1,103 @@
+---
+source: crates/ruff/tests/lint.rs
+info:
+  program: ruff
+  args:
+    - check
+    - "--no-cache"
+    - "--output-format"
+    - rdjson
+    - "--select"
+    - "F401,F821"
+    - "--target-version"
+    - py39
+    - input.py
+---
+success: false
+exit_code: 1
+----- stdout -----
+{
+  "diagnostics": [
+    {
+      "code": {
+        "url": "https://docs.astral.sh/ruff/rules/unused-import",
+        "value": "F401"
+      },
+      "location": {
+        "path": "[TMP]/input.py",
+        "range": {
+          "end": {
+            "column": 10,
+            "line": 1
+          },
+          "start": {
+            "column": 8,
+            "line": 1
+          }
+        }
+      },
+      "message": "`os` imported but unused",
+      "suggestions": [
+        {
+          "range": {
+            "end": {
+              "column": 1,
+              "line": 2
+            },
+            "start": {
+              "column": 1,
+              "line": 1
+            }
+          },
+          "text": ""
+        }
+      ]
+    },
+    {
+      "code": {
+        "url": "https://docs.astral.sh/ruff/rules/undefined-name",
+        "value": "F821"
+      },
+      "location": {
+        "path": "[TMP]/input.py",
+        "range": {
+          "end": {
+            "column": 6,
+            "line": 2
+          },
+          "start": {
+            "column": 5,
+            "line": 2
+          }
+        }
+      },
+      "message": "Undefined name `y`"
+    },
+    {
+      "code": {
+        "url": null,
+        "value": null
+      },
+      "location": {
+        "path": "[TMP]/input.py",
+        "range": {
+          "end": {
+            "column": 6,
+            "line": 3
+          },
+          "start": {
+            "column": 1,
+            "line": 3
+          }
+        }
+      },
+      "message": "SyntaxError: Cannot use `match` statement on Python 3.9 (syntax was added in Python 3.10)"
+    }
+  ],
+  "severity": "warning",
+  "source": {
+    "name": "ruff",
+    "url": "https://docs.astral.sh/ruff"
+  }
+}
+----- stderr -----
--- a/crates/ruff/tests/snapshots/lint__output_format_sarif.snap
+++ b/crates/ruff/tests/snapshots/lint__output_format_sarif.snap
@@ -0,0 +1,142 @@
+---
+source: crates/ruff/tests/lint.rs
+info:
+  program: ruff
+  args:
+    - check
+    - "--no-cache"
+    - "--output-format"
+    - sarif
+    - "--select"
+    - "F401,F821"
+    - "--target-version"
+    - py39
+    - input.py
+---
+success: false
+exit_code: 1
+----- stdout -----
+{
+  "$schema": "https://json.schemastore.org/sarif-2.1.0.json",
+  "runs": [
+    {
+      "results": [
+        {
+          "level": "error",
+          "locations": [
+            {
+              "physicalLocation": {
+                "artifactLocation": {
+                  "uri": "[TMP]/input.py"
+                },
+                "region": {
+                  "endColumn": 10,
+                  "endLine": 1,
+                  "startColumn": 8,
+                  "startLine": 1
+                }
+              }
+            }
+          ],
+          "message": {
+            "text": "`os` imported but unused"
+          },
+          "ruleId": "F401"
+        },
+        {
+          "level": "error",
+          "locations": [
+            {
+              "physicalLocation": {
+                "artifactLocation": {
+                  "uri": "[TMP]/input.py"
+                },
+                "region": {
+                  "endColumn": 6,
+                  "endLine": 2,
+                  "startColumn": 5,
+                  "startLine": 2
+                }
+              }
+            }
+          ],
+          "message": {
+            "text": "Undefined name `y`"
+          },
+          "ruleId": "F821"
+        },
+        {
+          "level": "error",
+          "locations": [
+            {
+              "physicalLocation": {
+                "artifactLocation": {
+                  "uri": "[TMP]/input.py"
+                },
+                "region": {
+                  "endColumn": 6,
+                  "endLine": 3,
+                  "startColumn": 1,
+                  "startLine": 3
+                }
+              }
+            }
+          ],
+          "message": {
+            "text": "SyntaxError: Cannot use `match` statement on Python 3.9 (syntax was added in Python 3.10)"
+          },
+          "ruleId": null
+        }
+      ],
+      "tool": {
+        "driver": {
+          "informationUri": "https://github.com/astral-sh/ruff",
+          "name": "ruff",
+          "rules": [
+            {
+              "fullDescription": {
+                "text": "## What it does\nChecks for unused imports.\n\n## Why is this bad?\nUnused imports add a performance overhead at runtime, and risk creating\nimport cycles. They also increase the cognitive load of reading the code.\n\nIf an import statement is used to check for the availability or existence\nof a module, consider using `importlib.util.find_spec` instead.\n\nIf an import statement is used to re-export a symbol as part of a module's\npublic interface, consider using a \"redundant\" import alias, which\ninstructs Ruff (and other tools) to respect the re-export, and avoid\nmarking it as unused, as in:\n\n```python\nfrom module import member as member\n```\n\nAlternatively, you can use `__all__` to declare a symbol as part of the module's\ninterface, as in:\n\n```python\n# __init__.py\nimport some_module\n\n__all__ = [\"some_module\"]\n```\n\n## Fix safety\n\nFixes to remove unused imports are safe, except in `__init__.py` files.\n\nApplying fixes to `__init__.py` files is currently in preview. The fix offered depends on the\ntype of the unused import. Ruff will suggest a safe fix to export first-party imports with\neither a redundant alias or, if already present in the file, an `__all__` entry. If multiple\n`__all__` declarations are present, Ruff will not offer a fix. Ruff will suggest an unsafe fix\nto remove third-party and standard library imports -- the fix is unsafe because the module's\ninterface changes.\n\n## Example\n\n```python\nimport numpy as np  # unused import\n\n\ndef area(radius):\n    return 3.14 * radius**2\n```\n\nUse instead:\n\n```python\ndef area(radius):\n    return 3.14 * radius**2\n```\n\nTo check the availability of a module, use `importlib.util.find_spec`:\n\n```python\nfrom importlib.util import find_spec\n\nif find_spec(\"numpy\") is not None:\n    print(\"numpy is installed\")\nelse:\n    print(\"numpy is not installed\")\n```\n\n## Preview\nWhen [preview](https://docs.astral.sh/ruff/preview/) is enabled,\nthe criterion for determining whether an import is first-party\nis stricter, which could affect the suggested fix. See [this FAQ section](https://docs.astral.sh/ruff/faq/#how-does-ruff-determine-which-of-my-imports-are-first-party-third-party-etc) for more details.\n\n## Options\n- `lint.ignore-init-module-imports`\n- `lint.pyflakes.allowed-unused-imports`\n\n## References\n- [Python documentation: `import`](https://docs.python.org/3/reference/simple_stmts.html#the-import-statement)\n- [Python documentation: `importlib.util.find_spec`](https://docs.python.org/3/library/importlib.html#importlib.util.find_spec)\n- [Typing documentation: interface conventions](https://typing.python.org/en/latest/source/libraries.html#library-interface-public-and-private-symbols)\n"
+              },
+              "help": {
+                "text": "`{name}` imported but unused; consider using `importlib.util.find_spec` to test for availability"
+              },
+              "helpUri": "https://docs.astral.sh/ruff/rules/unused-import",
+              "id": "F401",
+              "properties": {
+                "id": "F401",
+                "kind": "Pyflakes",
+                "name": "unused-import",
+                "problem.severity": "error"
+              },
+              "shortDescription": {
+                "text": "`{name}` imported but unused; consider using `importlib.util.find_spec` to test for availability"
+              }
+            },
+            {
+              "fullDescription": {
+                "text": "## What it does\nChecks for uses of undefined names.\n\n## Why is this bad?\nAn undefined name is likely to raise `NameError` at runtime.\n\n## Example\n```python\ndef double():\n    return n * 2  # raises `NameError` if `n` is undefined when `double` is called\n```\n\nUse instead:\n```python\ndef double(n):\n    return n * 2\n```\n\n## Options\n- [`target-version`]: Can be used to configure which symbols Ruff will understand\n  as being available in the `builtins` namespace.\n\n## References\n- [Python documentation: Naming and binding](https://docs.python.org/3/reference/executionmodel.html#naming-and-binding)\n"
+              },
+              "help": {
+                "text": "Undefined name `{name}`. {tip}"
+              },
+              "helpUri": "https://docs.astral.sh/ruff/rules/undefined-name",
+              "id": "F821",
+              "properties": {
+                "id": "F821",
+                "kind": "Pyflakes",
+                "name": "undefined-name",
+                "problem.severity": "error"
+              },
+              "shortDescription": {
+                "text": "Undefined name `{name}`. {tip}"
+              }
+            }
+          ],
+          "version": "[VERSION]"
+        }
+      }
+    }
+  ],
+  "version": "2.1.0"
+}
+----- stderr -----
--- a/crates/ruff_benchmark/benches/ty.rs
+++ b/crates/ruff_benchmark/benches/ty.rs
@@ -498,11 +498,8 @@ fn bench_project(benchmark: &ProjectBenchmark, criterion: &mut Criterion) {
        let diagnostics = result.len();

        assert!(
-            diagnostics > 1 && diagnostics <= max_diagnostics,
-            "Expected between {} and {} diagnostics but got {}",
-            1,
-            max_diagnostics,
-            diagnostics
+            diagnostics <= max_diagnostics,
+            "Expected <={max_diagnostics} diagnostics but got {diagnostics}"
        );
    }

@@ -570,6 +567,23 @@ fn anyio(criterion: &mut Criterion) {
    bench_project(&benchmark, criterion);
 }

+fn datetype(criterion: &mut Criterion) {
+    let benchmark = ProjectBenchmark::new(
+        RealWorldProject {
+            name: "DateType",
+            repository: "https://github.com/glyph/DateType",
+            commit: "57c9c93cf2468069f72945fc04bf27b64100dad8",
+            paths: vec![SystemPath::new("src")],
+            dependencies: vec![],
+            max_dep_date: "2025-07-04",
+            python_version: PythonVersion::PY313,
+        },
+        0,
+    );
+
+    bench_project(&benchmark, criterion);
+}
+
 criterion_group!(check_file, benchmark_cold, benchmark_incremental);
 criterion_group!(
    micro,
@@ -578,5 +592,5 @@ criterion_group!(
    benchmark_complex_constrained_attributes_1,
    benchmark_complex_constrained_attributes_2,
 );
-criterion_group!(project, anyio, attrs, hydra);
+criterion_group!(project, anyio, attrs, hydra, datetype);
 criterion_main!(check_file, micro, project);
--- a/crates/ruff_benchmark/benches/ty_walltime.rs
+++ b/crates/ruff_benchmark/benches/ty_walltime.rs
@@ -242,7 +242,7 @@ fn large(bencher: Bencher, benchmark: &Benchmark) {
    run_single_threaded(bencher, benchmark);
 }

-#[bench(args=[&*PYDANTIC], sample_size=3, sample_count=3)]
+#[bench(args=[&*PYDANTIC], sample_size=3, sample_count=8)]
 fn multithreaded(bencher: Bencher, benchmark: &Benchmark) {
    let thread_pool = ThreadPoolBuilder::new().build().unwrap();

--- a/crates/ruff_db/Cargo.toml
+++ b/crates/ruff_db/Cargo.toml
@@ -13,12 +13,14 @@ license = { workspace = true }
 [dependencies]
 ruff_annotate_snippets = { workspace = true }
 ruff_cache = { workspace = true, optional = true }
+ruff_diagnostics = { workspace = true }
 ruff_notebook = { workspace = true }
 ruff_python_ast = { workspace = true, features = ["get-size"] }
 ruff_python_parser = { workspace = true }
 ruff_python_trivia = { workspace = true }
 ruff_source_file = { workspace = true, features = ["get-size"] }
 ruff_text_size = { workspace = true }
+ty_static = { workspace = true }

 anstyle = { workspace = true }
 arc-swap = { workspace = true }
--- a/crates/ruff_db/src/diagnostic/mod.rs
+++ b/crates/ruff_db/src/diagnostic/mod.rs
@@ -1,10 +1,11 @@
 use std::{fmt::Formatter, sync::Arc};

 use render::{FileResolver, Input};
-use ruff_source_file::{SourceCode, SourceFile};
+use ruff_diagnostics::Fix;
+use ruff_source_file::{LineColumn, SourceCode, SourceFile};

 use ruff_annotate_snippets::Level as AnnotateLevel;
-use ruff_text_size::{Ranged, TextRange};
+use ruff_text_size::{Ranged, TextRange, TextSize};

 pub use self::render::DisplayDiagnostic;
 use crate::{Db, files::File};
@@ -62,10 +63,37 @@ impl Diagnostic {
            message: message.into_diagnostic_message(),
            annotations: vec![],
            subs: vec![],
+            fix: None,
+            parent: None,
+            noqa_offset: None,
+            secondary_code: None,
        });
        Diagnostic { inner }
    }

+    /// Creates a `Diagnostic` for a syntax error.
+    ///
+    /// Unlike the more general [`Diagnostic::new`], this requires a [`Span`] and a [`TextRange`]
+    /// attached to it.
+    ///
+    /// This should _probably_ be a method on the syntax errors, but
+    /// at time of writing, `ruff_db` depends on `ruff_python_parser` instead of
+    /// the other way around. And since we want to do this conversion in a couple
+    /// places, it makes sense to centralize it _somewhere_. So it's here for now.
+    ///
+    /// Note that `message` is stored in the primary annotation, _not_ in the primary diagnostic
+    /// message.
+    pub fn invalid_syntax(
+        span: impl Into<Span>,
+        message: impl IntoDiagnosticMessage,
+        range: impl Ranged,
+    ) -> Diagnostic {
+        let mut diag = Diagnostic::new(DiagnosticId::InvalidSyntax, Severity::Error, "");
+        let span = span.into().with_range(range.range());
+        diag.annotate(Annotation::primary(span).message(message));
+        diag
+    }
+
    /// Add an annotation to this diagnostic.
    ///
    /// Annotations for a diagnostic are optional, but if any are added,
@@ -226,6 +254,11 @@ impl Diagnostic {
        self.primary_annotation().map(|ann| ann.span.clone())
    }

+    /// Returns a reference to the primary span of this diagnostic.
+    pub fn primary_span_ref(&self) -> Option<&Span> {
+        self.primary_annotation().map(|ann| &ann.span)
+    }
+
    /// Returns the tags from the primary annotation of this diagnostic if it exists.
    pub fn primary_tags(&self) -> Option<&[DiagnosticTag]> {
        self.primary_annotation().map(|ann| ann.tags.as_slice())
@@ -268,6 +301,163 @@ impl Diagnostic {
    pub fn sub_diagnostics(&self) -> &[SubDiagnostic] {
        &self.inner.subs
    }
+
+    /// Returns the fix for this diagnostic if it exists.
+    pub fn fix(&self) -> Option<&Fix> {
+        self.inner.fix.as_ref()
+    }
+
+    /// Set the fix for this diagnostic.
+    pub fn set_fix(&mut self, fix: Fix) {
+        Arc::make_mut(&mut self.inner).fix = Some(fix);
+    }
+
+    /// Remove the fix for this diagnostic.
+    pub fn remove_fix(&mut self) {
+        Arc::make_mut(&mut self.inner).fix = None;
+    }
+
+    /// Returns `true` if the diagnostic contains a [`Fix`].
+    pub fn fixable(&self) -> bool {
+        self.fix().is_some()
+    }
+
+    /// Returns the offset of the parent statement for this diagnostic if it exists.
+    ///
+    /// This is primarily used for checking noqa/secondary code suppressions.
+    pub fn parent(&self) -> Option<TextSize> {
+        self.inner.parent
+    }
+
+    /// Set the offset of the diagnostic's parent statement.
+    pub fn set_parent(&mut self, parent: TextSize) {
+        Arc::make_mut(&mut self.inner).parent = Some(parent);
+    }
+
+    /// Returns the remapped offset for a suppression comment if it exists.
+    ///
+    /// Like [`Diagnostic::parent`], this is used for noqa code suppression comments in Ruff.
+    pub fn noqa_offset(&self) -> Option<TextSize> {
+        self.inner.noqa_offset
+    }
+
+    /// Set the remapped offset for a suppression comment.
+    pub fn set_noqa_offset(&mut self, noqa_offset: TextSize) {
+        Arc::make_mut(&mut self.inner).noqa_offset = Some(noqa_offset);
+    }
+
+    /// Returns the secondary code for the diagnostic if it exists.
+    ///
+    /// The "primary" code for the diagnostic is its lint name. Diagnostics in ty don't have
+    /// secondary codes (yet), but in Ruff the noqa code is used.
+    pub fn secondary_code(&self) -> Option<&SecondaryCode> {
+        self.inner.secondary_code.as_ref()
+    }
+
+    /// Set the secondary code for this diagnostic.
+    pub fn set_secondary_code(&mut self, code: SecondaryCode) {
+        Arc::make_mut(&mut self.inner).secondary_code = Some(code);
+    }
+
+    /// Returns the name used to represent the diagnostic.
+    pub fn name(&self) -> &'static str {
+        self.id().as_str()
+    }
+
+    /// Returns `true` if `self` is a syntax error message.
+    pub fn is_invalid_syntax(&self) -> bool {
+        self.id().is_invalid_syntax()
+    }
+
+    /// Returns the message body to display to the user.
+    pub fn body(&self) -> &str {
+        self.primary_message()
+    }
+
+    /// Returns the fix suggestion for the violation.
+    pub fn suggestion(&self) -> Option<&str> {
+        self.primary_annotation()?.get_message()
+    }
+
+    /// Returns the URL for the rule documentation, if it exists.
+    pub fn to_url(&self) -> Option<String> {
+        if self.is_invalid_syntax() {
+            None
+        } else {
+            Some(format!(
+                "{}/rules/{}",
+                env!("CARGO_PKG_HOMEPAGE"),
+                self.name()
+            ))
+        }
+    }
+
+    /// Returns the filename for the message.
+    ///
+    /// Panics if the diagnostic has no primary span, or if its file is not a `SourceFile`.
+    pub fn expect_ruff_filename(&self) -> String {
+        self.expect_primary_span()
+            .expect_ruff_file()
+            .name()
+            .to_string()
+    }
+
+    /// Computes the start source location for the message.
+    ///
+    /// Panics if the diagnostic has no primary span, if its file is not a `SourceFile`, or if the
+    /// span has no range.
+    pub fn expect_ruff_start_location(&self) -> LineColumn {
+        self.expect_primary_span()
+            .expect_ruff_file()
+            .to_source_code()
+            .line_column(self.expect_range().start())
+    }
+
+    /// Computes the end source location for the message.
+    ///
+    /// Panics if the diagnostic has no primary span, if its file is not a `SourceFile`, or if the
+    /// span has no range.
+    pub fn expect_ruff_end_location(&self) -> LineColumn {
+        self.expect_primary_span()
+            .expect_ruff_file()
+            .to_source_code()
+            .line_column(self.expect_range().end())
+    }
+
+    /// Returns the [`SourceFile`] which the message belongs to.
+    pub fn ruff_source_file(&self) -> Option<&SourceFile> {
+        self.primary_span_ref()?.as_ruff_file()
+    }
+
+    /// Returns the [`SourceFile`] which the message belongs to.
+    ///
+    /// Panics if the diagnostic has no primary span, or if its file is not a `SourceFile`.
+    pub fn expect_ruff_source_file(&self) -> SourceFile {
+        self.expect_primary_span().expect_ruff_file().clone()
+    }
+
+    /// Returns the [`TextRange`] for the diagnostic.
+    pub fn range(&self) -> Option<TextRange> {
+        self.primary_span()?.range()
+    }
+
+    /// Returns the [`TextRange`] for the diagnostic.
+    ///
+    /// Panics if the diagnostic has no primary span or if the span has no range.
+    pub fn expect_range(&self) -> TextRange {
+        self.range().expect("Expected a range for the primary span")
+    }
+
+    /// Returns the ordering of diagnostics based on the start of their ranges, if they have any.
+    ///
+    /// Panics if either diagnostic has no primary span, if the span has no range, or if its file is
+    /// not a `SourceFile`.
+    pub fn ruff_start_ordering(&self, other: &Self) -> std::cmp::Ordering {
+        (self.expect_ruff_source_file(), self.expect_range().start()).cmp(&(
+            other.expect_ruff_source_file(),
+            other.expect_range().start(),
+        ))
+    }
 }

 #[derive(Debug, Clone, Eq, PartialEq, get_size2::GetSize)]
@@ -277,6 +467,10 @@ struct DiagnosticInner {
    message: DiagnosticMessage,
    annotations: Vec<Annotation>,
    subs: Vec<SubDiagnostic>,
+    fix: Option<Fix>,
+    parent: Option<TextSize>,
+    noqa_offset: Option<TextSize>,
+    secondary_code: Option<SecondaryCode>,
 }

 struct RenderingSortKey<'a> {
@@ -897,9 +1091,15 @@ impl Span {
    ///
    /// Panics if the file is a [`UnifiedFile::Ty`] instead of a [`UnifiedFile::Ruff`].
    pub fn expect_ruff_file(&self) -> &SourceFile {
+        self.as_ruff_file()
+            .expect("Expected a ruff `SourceFile`, found a ty `File`")
+    }
+
+    /// Returns the [`SourceFile`] attached to this [`Span`].
+    pub fn as_ruff_file(&self) -> Option<&SourceFile> {
        match &self.file {
-            UnifiedFile::Ty(_) => panic!("Expected a ruff `SourceFile`, found a ty `File`"),
-            UnifiedFile::Ruff(file) => file,
+            UnifiedFile::Ty(_) => None,
+            UnifiedFile::Ruff(file) => Some(file),
        }
    }
 }
@@ -1147,41 +1347,52 @@ impl<T: std::fmt::Display> IntoDiagnosticMessage for T {
    }
 }

-/// Creates a `Diagnostic` from a parse error.
+/// A secondary identifier for a lint diagnostic.
 ///
-/// This should _probably_ be a method on `ruff_python_parser::ParseError`, but
-/// at time of writing, `ruff_db` depends on `ruff_python_parser` instead of
-/// the other way around. And since we want to do this conversion in a couple
-/// places, it makes sense to centralize it _somewhere_. So it's here for now.
-pub fn create_parse_diagnostic(file: File, err: &ruff_python_parser::ParseError) -> Diagnostic {
-    let mut diag = Diagnostic::new(DiagnosticId::InvalidSyntax, Severity::Error, "");
-    let span = Span::from(file).with_range(err.location);
-    diag.annotate(Annotation::primary(span).message(&err.error));
-    diag
+/// For Ruff rules this means the noqa code.
+#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Default, Hash, get_size2::GetSize)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize), serde(transparent))]
+pub struct SecondaryCode(String);
+
+impl SecondaryCode {
+    pub fn new(code: String) -> Self {
+        Self(code)
+    }
+
+    pub fn as_str(&self) -> &str {
+        &self.0
+    }
 }

-/// Creates a `Diagnostic` from an unsupported syntax error.
-///
-/// See [`create_parse_diagnostic`] for more details.
-pub fn create_unsupported_syntax_diagnostic(
-    file: File,
-    err: &ruff_python_parser::UnsupportedSyntaxError,
-) -> Diagnostic {
-    let mut diag = Diagnostic::new(DiagnosticId::InvalidSyntax, Severity::Error, "");
-    let span = Span::from(file).with_range(err.range);
-    diag.annotate(Annotation::primary(span).message(err.to_string()));
-    diag
+impl std::fmt::Display for SecondaryCode {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str(&self.0)
+    }
 }

-/// Creates a `Diagnostic` from a semantic syntax error.
-///
-/// See [`create_parse_diagnostic`] for more details.
-pub fn create_semantic_syntax_diagnostic(
-    file: File,
-    err: &ruff_python_parser::semantic_errors::SemanticSyntaxError,
-) -> Diagnostic {
-    let mut diag = Diagnostic::new(DiagnosticId::InvalidSyntax, Severity::Error, "");
-    let span = Span::from(file).with_range(err.range);
-    diag.annotate(Annotation::primary(span).message(err.to_string()));
-    diag
+impl std::ops::Deref for SecondaryCode {
+    type Target = str;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl PartialEq<&str> for SecondaryCode {
+    fn eq(&self, other: &&str) -> bool {
+        self.0 == *other
+    }
+}
+
+impl PartialEq<SecondaryCode> for &str {
+    fn eq(&self, other: &SecondaryCode) -> bool {
+        other.eq(self)
+    }
+}
+
+// for `hashbrown::EntryRef`
+impl From<&SecondaryCode> for SecondaryCode {
+    fn from(value: &SecondaryCode) -> Self {
+        value.clone()
+    }
 }
--- a/crates/ruff_db/src/lib.rs
+++ b/crates/ruff_db/src/lib.rs
@@ -5,6 +5,7 @@ use ruff_python_ast::PythonVersion;
 use rustc_hash::FxHasher;
 use std::hash::BuildHasherDefault;
 use std::num::NonZeroUsize;
+use ty_static::EnvVars;

 pub mod diagnostic;
 pub mod display;
@@ -50,8 +51,8 @@ pub trait Db: salsa::Database {
 /// ty can still spawn more threads for other tasks, e.g. to wait for a Ctrl+C signal or
 /// watching the files for changes.
 pub fn max_parallelism() -> NonZeroUsize {
-    std::env::var("TY_MAX_PARALLELISM")
-        .or_else(|_| std::env::var("RAYON_NUM_THREADS"))
+    std::env::var(EnvVars::TY_MAX_PARALLELISM)
+        .or_else(|_| std::env::var(EnvVars::RAYON_NUM_THREADS))
        .ok()
        .and_then(|s| s.parse().ok())
        .unwrap_or_else(|| {
--- a/crates/ruff_dev/Cargo.toml
+++ b/crates/ruff_dev/Cargo.toml
@@ -13,6 +13,7 @@ license = { workspace = true }
 [dependencies]
 ty = { workspace = true }
 ty_project = { workspace = true, features = ["schemars"] }
+ty_static = { workspace = true }
 ruff = { workspace = true }
 ruff_formatter = { workspace = true }
 ruff_linter = { workspace = true, features = ["schemars"] }
--- a/crates/ruff_dev/src/generate_all.rs
+++ b/crates/ruff_dev/src/generate_all.rs
@@ -4,7 +4,7 @@ use anyhow::Result;

 use crate::{
    generate_cli_help, generate_docs, generate_json_schema, generate_ty_cli_reference,
-    generate_ty_options, generate_ty_rules, generate_ty_schema,
+    generate_ty_env_vars_reference, generate_ty_options, generate_ty_rules, generate_ty_schema,
 };

 pub(crate) const REGENERATE_ALL_COMMAND: &str = "cargo dev generate-all";
@@ -44,5 +44,8 @@ pub(crate) fn main(args: &Args) -> Result<()> {
    generate_ty_options::main(&generate_ty_options::Args { mode: args.mode })?;
    generate_ty_rules::main(&generate_ty_rules::Args { mode: args.mode })?;
    generate_ty_cli_reference::main(&generate_ty_cli_reference::Args { mode: args.mode })?;
+    generate_ty_env_vars_reference::main(&generate_ty_env_vars_reference::Args {
+        mode: args.mode,
+    })?;
    Ok(())
 }
--- a/crates/ruff_dev/src/generate_ty_env_vars_reference.rs
+++ b/crates/ruff_dev/src/generate_ty_env_vars_reference.rs
@@ -0,0 +1,119 @@
+//! Generate the environment variables reference from `ty_static::EnvVars`.
+
+use std::collections::BTreeSet;
+use std::fs;
+use std::path::PathBuf;
+
+use anyhow::bail;
+use pretty_assertions::StrComparison;
+
+use ty_static::EnvVars;
+
+use crate::generate_all::Mode;
+
+#[derive(clap::Args)]
+pub(crate) struct Args {
+    #[arg(long, default_value_t, value_enum)]
+    pub(crate) mode: Mode,
+}
+
+pub(crate) fn main(args: &Args) -> anyhow::Result<()> {
+    let reference_string = generate();
+    let filename = "environment.md";
+    let reference_path = PathBuf::from(env!("CARGO_MANIFEST_DIR"))
+        .parent()
+        .unwrap()
+        .parent()
+        .unwrap()
+        .join("crates")
+        .join("ty")
+        .join("docs")
+        .join(filename);
+
+    match args.mode {
+        Mode::DryRun => {
+            println!("{reference_string}");
+        }
+        Mode::Check => match fs::read_to_string(&reference_path) {
+            Ok(current) => {
+                if current == reference_string {
+                    println!("Up-to-date: {filename}");
+                } else {
+                    let comparison = StrComparison::new(&current, &reference_string);
+                    bail!(
+                        "{filename} changed, please run `cargo dev generate-ty-env-vars-reference`:\n{comparison}"
+                    );
+                }
+            }
+            Err(err) if err.kind() == std::io::ErrorKind::NotFound => {
+                bail!(
+                    "{filename} not found, please run `cargo dev generate-ty-env-vars-reference`"
+                );
+            }
+            Err(err) => {
+                bail!(
+                    "{filename} changed, please run `cargo dev generate-ty-env-vars-reference`:\n{err}"
+                );
+            }
+        },
+        Mode::Write => {
+            // Ensure the docs directory exists
+            if let Some(parent) = reference_path.parent() {
+                fs::create_dir_all(parent)?;
+            }
+
+            match fs::read_to_string(&reference_path) {
+                Ok(current) => {
+                    if current == reference_string {
+                        println!("Up-to-date: {filename}");
+                    } else {
+                        println!("Updating: {filename}");
+                        fs::write(&reference_path, reference_string.as_bytes())?;
+                    }
+                }
+                Err(err) if err.kind() == std::io::ErrorKind::NotFound => {
+                    println!("Updating: {filename}");
+                    fs::write(&reference_path, reference_string.as_bytes())?;
+                }
+                Err(err) => {
+                    bail!(
+                        "{filename} changed, please run `cargo dev generate-ty-env-vars-reference`:\n{err}"
+                    );
+                }
+            }
+        }
+    }
+
+    Ok(())
+}
+
+fn generate() -> String {
+    let mut output = String::new();
+
+    output.push_str("# Environment variables\n\n");
+
+    // Partition and sort environment variables into TY_ and external variables.
+    let (ty_vars, external_vars): (BTreeSet<_>, BTreeSet<_>) = EnvVars::metadata()
+        .iter()
+        .partition(|(var, _)| var.starts_with("TY_"));
+
+    output.push_str("ty defines and respects the following environment variables:\n\n");
+
+    for (var, doc) in ty_vars {
+        output.push_str(&render(var, doc));
+    }
+
+    output.push_str("## Externally-defined variables\n\n");
+    output.push_str("ty also reads the following externally defined environment variables:\n\n");
+
+    for (var, doc) in external_vars {
+        output.push_str(&render(var, doc));
+    }
+
+    output
+}
+
+/// Render an environment variable and its documentation.
+fn render(var: &str, doc: &str) -> String {
+    format!("### `{var}`\n\n{doc}\n\n")
+}
--- a/crates/ruff_dev/src/generate_ty_rules.rs
+++ b/crates/ruff_dev/src/generate_ty_rules.rs
@@ -73,11 +73,16 @@ fn generate_markdown() -> String {
    for lint in lints {
        let _ = writeln!(&mut output, "## `{rule_name}`\n", rule_name = lint.name());

-        // Increase the header-level by one
+        // Reformat headers as bold text
+        let mut in_code_fence = false;
        let documentation = lint
            .documentation_lines()
            .map(|line| {
-                if line.starts_with('#') {
+                // Toggle the code fence state if we encounter a boundary
+                if line.starts_with("```") {
+                    in_code_fence = !in_code_fence;
+                }
+                if !in_code_fence && line.starts_with('#') {
                    Cow::Owned(format!(
                        "**{line}**\n",
                        line = line.trim_start_matches('#').trim_start()
--- a/crates/ruff_dev/src/main.rs
+++ b/crates/ruff_dev/src/main.rs
@@ -18,6 +18,7 @@ mod generate_json_schema;
 mod generate_options;
 mod generate_rules_table;
 mod generate_ty_cli_reference;
+mod generate_ty_env_vars_reference;
 mod generate_ty_options;
 mod generate_ty_rules;
 mod generate_ty_schema;
@@ -53,6 +54,8 @@ enum Command {
    /// Generate a Markdown-compatible listing of configuration options.
    GenerateOptions,
    GenerateTyOptions(generate_ty_options::Args),
+    /// Generate environment variables reference for ty.
+    GenerateTyEnvVarsReference(generate_ty_env_vars_reference::Args),
    /// Generate CLI help.
    GenerateCliHelp(generate_cli_help::Args),
    /// Generate Markdown docs.
@@ -98,6 +101,7 @@ fn main() -> Result<ExitCode> {
        Command::GenerateTyRules(args) => generate_ty_rules::main(&args)?,
        Command::GenerateOptions => println!("{}", generate_options::generate()),
        Command::GenerateTyOptions(args) => generate_ty_options::main(&args)?,
+        Command::GenerateTyEnvVarsReference(args) => generate_ty_env_vars_reference::main(&args)?,
        Command::GenerateCliHelp(args) => generate_cli_help::main(&args)?,
        Command::GenerateDocs(args) => generate_docs::main(&args)?,
        Command::PrintAST(args) => print_ast::main(&args)?,
--- a/crates/ruff_diagnostics/Cargo.toml
+++ b/crates/ruff_diagnostics/Cargo.toml
@@ -16,5 +16,6 @@ doctest = false
 [dependencies]
 ruff_text_size = { workspace = true }

+get-size2 = { workspace = true }
 is-macro = { workspace = true }
 serde = { workspace = true, optional = true, features = [] }
--- a/crates/ruff_diagnostics/src/edit.rs
+++ b/crates/ruff_diagnostics/src/edit.rs
@@ -7,7 +7,7 @@ use ruff_text_size::{Ranged, TextRange, TextSize};

 /// A text edit to be applied to a source file. Inserts, deletes, or replaces
 /// content at a given location.
-#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash, get_size2::GetSize)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct Edit {
    /// The start location of the edit.
--- a/crates/ruff_diagnostics/src/fix.rs
+++ b/crates/ruff_diagnostics/src/fix.rs
@@ -6,7 +6,9 @@ use ruff_text_size::{Ranged, TextSize};
 use crate::edit::Edit;

 /// Indicates if a fix can be applied.
-#[derive(Copy, Clone, Debug, Hash, PartialEq, Eq, PartialOrd, Ord, is_macro::Is)]
+#[derive(
+    Copy, Clone, Debug, Hash, PartialEq, Eq, PartialOrd, Ord, is_macro::Is, get_size2::GetSize,
+)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 #[cfg_attr(feature = "serde", serde(rename_all = "lowercase"))]
 pub enum Applicability {
@@ -30,7 +32,7 @@ pub enum Applicability {
 }

 /// Indicates the level of isolation required to apply a fix.
-#[derive(Default, Copy, Clone, Debug, Hash, PartialEq, Eq, PartialOrd, Ord)]
+#[derive(Default, Copy, Clone, Debug, Hash, PartialEq, Eq, PartialOrd, Ord, get_size2::GetSize)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum IsolationLevel {
    /// The fix should be applied as long as no other fixes in the same group have been applied.
@@ -41,7 +43,7 @@ pub enum IsolationLevel {
 }

 /// A collection of [`Edit`] elements to be applied to a source file.
-#[derive(Debug, PartialEq, Eq, Clone)]
+#[derive(Debug, PartialEq, Eq, Clone, get_size2::GetSize)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct Fix {
    /// The [`Edit`] elements to be applied, sorted by [`Edit::start`] in ascending order.
--- a/crates/ruff_linter/Cargo.toml
+++ b/crates/ruff_linter/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "ruff_linter"
-version = "0.12.1"
+version = "0.12.3"
 publish = false
 authors = { workspace = true }
 edition = { workspace = true }
@@ -15,7 +15,7 @@ license = { workspace = true }
 [dependencies]
 ruff_annotate_snippets = { workspace = true }
 ruff_cache = { workspace = true }
-ruff_db = { workspace = true }
+ruff_db = { workspace = true, features = ["serde"] }
 ruff_diagnostics = { workspace = true, features = ["serde"] }
 ruff_notebook = { workspace = true }
 ruff_macros = { workspace = true }
--- a/crates/ruff_linter/resources/test/fixtures/flake8_bandit/S112.py
+++ b/crates/ruff_linter/resources/test/fixtures/flake8_bandit/S112.py
@@ -1,29 +1,30 @@
-try:
-    pass
-except Exception:
-    continue
+for _ in []:
+    try:
+        pass
+    except Exception:
+        continue

-try:
-    pass
-except:
-    continue
+    try:
+        pass
+    except:
+        continue

-try:
-    pass
-except (Exception,):
-    continue
+    try:
+        pass
+    except (Exception,):
+        continue

-try:
-    pass
-except (Exception, ValueError):
-    continue
+    try:
+        pass
+    except (Exception, ValueError):
+        continue

-try:
-    pass
-except ValueError:
-    continue
+    try:
+        pass
+    except ValueError:
+        continue

-try:
-    pass
-except (ValueError,):
-    continue
+    try:
+        pass
+    except (ValueError,):
+        continue
--- a/crates/ruff_linter/resources/test/fixtures/flake8_bugbear/B017_0.py
+++ b/crates/ruff_linter/resources/test/fixtures/flake8_bugbear/B017_0.py
@@ -1,10 +1,10 @@
 """
 Should emit:
-B017 - on lines 23 and 41
+B017 - on lines 24, 28, 46, 49, 52, and 58
 """
 import asyncio
 import unittest
-import pytest
+import pytest, contextlib

 CONSTANT = True

--- a/crates/ruff_linter/resources/test/fixtures/flake8_bugbear/B017_1.py
+++ b/crates/ruff_linter/resources/test/fixtures/flake8_bugbear/B017_1.py
@@ -0,0 +1,28 @@
+"""
+Should emit:
+B017 - on lines 20, 21, 25, and 26
+"""
+import unittest
+import pytest
+
+
+def something_else() -> None:
+    for i in (1, 2, 3):
+        print(i)
+
+
+class Foo:
+    pass
+
+
+class Foobar(unittest.TestCase):
+    def call_form_raises(self) -> None:
+        self.assertRaises(Exception, something_else)
+        self.assertRaises(BaseException, something_else)
+
+
+def test_pytest_call_form() -> None:
+    pytest.raises(Exception, something_else)
+    pytest.raises(BaseException, something_else)
+
+    pytest.raises(Exception, something_else, match="hello")
--- a/crates/ruff_linter/resources/test/fixtures/flake8_bugbear/B031.py
+++ b/crates/ruff_linter/resources/test/fixtures/flake8_bugbear/B031.py
@@ -185,38 +185,45 @@ for _section, section_items in groupby(items, key=lambda p: p[1]):
    collect_shop_items(shopper, section_items)

 # Shouldn't trigger the warning when there is a return statement.
-for _section, section_items in groupby(items, key=lambda p: p[1]):
-    if _section == "greens":
+def foo():
+    for _section, section_items in groupby(items, key=lambda p: p[1]):
+        if _section == "greens":
+            collect_shop_items(shopper, section_items)
+            return
+        elif _section == "frozen items":
+            return section_items
        collect_shop_items(shopper, section_items)
-        return
-    elif _section == "frozen items":
-        return section_items
-    collect_shop_items(shopper, section_items)

 # Should trigger the warning for duplicate access, even if is a return statement after.
-for _section, section_items in groupby(items, key=lambda p: p[1]):
-    if _section == "greens":
-        collect_shop_items(shopper, section_items)
-        collect_shop_items(shopper, section_items)
-        return
+def foo():
+    from itertools import groupby
+    for _section, section_items in groupby(items, key=lambda p: p[1]):
+        if _section == "greens":
+            collect_shop_items(shopper, section_items)
+            collect_shop_items(shopper, section_items)
+            return

 # Should trigger the warning for duplicate access, even if is a return in another branch.
-for _section, section_items in groupby(items, key=lambda p: p[1]):
-    if _section == "greens":
-        collect_shop_items(shopper, section_items)
-        return
-    elif _section == "frozen items":
-        collect_shop_items(shopper, section_items)
-        collect_shop_items(shopper, section_items)
+def foo():
+    from itertools import groupby
+    for _section, section_items in groupby(items, key=lambda p: p[1]):
+        if _section == "greens":
+            collect_shop_items(shopper, section_items)
+            return
+        elif _section == "frozen items":
+            collect_shop_items(shopper, section_items)
+            collect_shop_items(shopper, section_items)

 # Should trigger, since only one branch has a return statement.
-for _section, section_items in groupby(items, key=lambda p: p[1]):
-    if _section == "greens":
-        collect_shop_items(shopper, section_items)
-        return
-    elif _section == "frozen items":
-        collect_shop_items(shopper, section_items)
-    collect_shop_items(shopper, section_items)  # B031
+def foo():
+    from itertools import groupby
+    for _section, section_items in groupby(items, key=lambda p: p[1]):
+        if _section == "greens":
+            collect_shop_items(shopper, section_items)
+            return
+        elif _section == "frozen items":
+            collect_shop_items(shopper, section_items)
+        collect_shop_items(shopper, section_items)  # B031

 # Let's redefine the `groupby` function to make sure we pick up the correct one.
 # NOTE: This should always be at the end of the file.
--- a/crates/ruff_linter/resources/test/fixtures/flake8_pie/PIE804.py
+++ b/crates/ruff_linter/resources/test/fixtures/flake8_pie/PIE804.py
@@ -26,8 +26,9 @@ abc(**{'a': b}, **{'a': c})  # PIE804
 abc(a=1, **{'a': c}, **{'b': c})  # PIE804

 # Some values need to be parenthesized.
-abc(foo=1, **{'bar': (bar := 1)})  # PIE804
-abc(foo=1, **{'bar': (yield 1)})  # PIE804
+def foo():
+    abc(foo=1, **{'bar': (bar := 1)})  # PIE804
+    abc(foo=1, **{'bar': (yield 1)})  # PIE804

 # https://github.com/astral-sh/ruff/issues/18036
 # The autofix for this is unsafe due to the comments inside the dictionary.
--- a/crates/ruff_linter/resources/test/fixtures/flake8_return/RET504.py
+++ b/crates/ruff_linter/resources/test/fixtures/flake8_return/RET504.py
@@ -422,6 +422,35 @@ def func(a: dict[str, int]) -> list[dict[str, int]]:
        services = a["services"]
        return services

+
+# See: https://github.com/astral-sh/ruff/issues/14052
+def outer() -> list[object]:
+    @register
+    async def inner() -> None:
+        print(layout)
+
+    layout = [...]
+    return layout
+
+def outer() -> list[object]:
+    with open("") as f:
+        async def inner() -> None:
+            print(layout)
+
+    layout = [...]
+    return layout
+
+
+def outer() -> list[object]:
+    def inner():
+        with open("") as f:
+            async def inner_inner() -> None:
+                print(layout)
+
+    layout = [...]
+    return layout
+
+
 # See: https://github.com/astral-sh/ruff/issues/18411
 def f():
    (#=
--- a/crates/ruff_linter/resources/test/fixtures/flake8_simplify/SIM115.py
+++ b/crates/ruff_linter/resources/test/fixtures/flake8_simplify/SIM115.py
@@ -27,8 +27,9 @@ with contextlib.ExitStack() as stack:
    close_files = stack.pop_all().close

 # OK
-with contextlib.AsyncExitStack() as exit_stack:
-    f = await exit_stack.enter_async_context(open("filename"))
+async def foo():
+    with contextlib.AsyncExitStack() as exit_stack:
+        f = await exit_stack.enter_async_context(open("filename"))

 # OK (false negative)
 with contextlib.ExitStack():
@@ -275,9 +276,10 @@ class ExampleClassTests(TestCase):
        cls.enterClassContext(open("filename"))

 # OK
-class ExampleAsyncTests(IsolatedAsyncioTestCase):
-    async def test_something(self):
-        await self.enterAsyncContext(open("filename"))
+async def foo():
+    class ExampleAsyncTests(IsolatedAsyncioTestCase):
+        async def test_something(self):
+            await self.enterAsyncContext(open("filename"))

 # OK
 class ExampleTests(TestCase):
--- a/crates/ruff_linter/resources/test/fixtures/flake8_simplify/SIM116.py
+++ b/crates/ruff_linter/resources/test/fixtures/flake8_simplify/SIM116.py
@@ -1,98 +1,99 @@
-# Errors
-a = "hello"
+def foo():
+    # Errors
+    a = "hello"

-# SIM116
-if a == "foo":
-    return "bar"
-elif a == "bar":
-    return "baz"
-elif a == "boo":
-    return "ooh"
-else:
-    return 42
-
-# SIM116
-if a == 1:
-    return (1, 2, 3)
-elif a == 2:
-    return (4, 5, 6)
-elif a == 3:
-    return (7, 8, 9)
-else:
-    return (10, 11, 12)
-
-# SIM116
-if a == 1:
-    return (1, 2, 3)
-elif a == 2:
-    return (4, 5, 6)
-elif a == 3:
-    return (7, 8, 9)
-
-# SIM116
-if a == "hello 'sir'":
-    return (1, 2, 3)
-elif a == 'goodbye "mam"':
-    return (4, 5, 6)
-elif a == """Fairwell 'mister'""":
-    return (7, 8, 9)
-else:
-    return (10, 11, 12)
-
-# SIM116
-if a == b"one":
-    return 1
-elif a == b"two":
-    return 2
-elif a == b"three":
-    return 3
-
-# SIM116
-if a == "hello 'sir'":
-    return ("hello'", 'hi"', 3)
-elif a == 'goodbye "mam"':
-    return (4, 5, 6)
-elif a == """Fairwell 'mister'""":
-    return (7, 8, 9)
-else:
-    return (10, 11, 12)
-
-# OK
-if a == "foo":
-    return "bar"
-elif a == "bar":
-    return baz()
-elif a == "boo":
-    return "ooh"
-else:
-    return 42
-
-# OK
-if a == b"one":
-    return 1
-elif b == b"two":
-    return 2
-elif a == b"three":
-    return 3
-
-# SIM116
-if func_name == "create":
-    return "A"
-elif func_name == "modify":
-    return "M"
-elif func_name == "remove":
-    return "D"
-elif func_name == "move":
-    return "MV"
-
-# OK
-def no_return_in_else(platform):
-    if platform == "linux":
-        return "auditwheel repair -w {dest_dir} {wheel}"
-    elif platform == "macos":
-        return "delocate-wheel --require-archs {delocate_archs} -w {dest_dir} -v {wheel}"
-    elif platform == "windows":
-        return ""
+    # SIM116
+    if a == "foo":
+        return "bar"
+    elif a == "bar":
+        return "baz"
+    elif a == "boo":
+        return "ooh"
    else:
-        msg = f"Unknown platform: {platform!r}"
-        raise ValueError(msg)
+        return 42
+
+    # SIM116
+    if a == 1:
+        return (1, 2, 3)
+    elif a == 2:
+        return (4, 5, 6)
+    elif a == 3:
+        return (7, 8, 9)
+    else:
+        return (10, 11, 12)
+
+    # SIM116
+    if a == 1:
+        return (1, 2, 3)
+    elif a == 2:
+        return (4, 5, 6)
+    elif a == 3:
+        return (7, 8, 9)
+
+    # SIM116
+    if a == "hello 'sir'":
+        return (1, 2, 3)
+    elif a == 'goodbye "mam"':
+        return (4, 5, 6)
+    elif a == """Fairwell 'mister'""":
+        return (7, 8, 9)
+    else:
+        return (10, 11, 12)
+
+    # SIM116
+    if a == b"one":
+        return 1
+    elif a == b"two":
+        return 2
+    elif a == b"three":
+        return 3
+
+    # SIM116
+    if a == "hello 'sir'":
+        return ("hello'", 'hi"', 3)
+    elif a == 'goodbye "mam"':
+        return (4, 5, 6)
+    elif a == """Fairwell 'mister'""":
+        return (7, 8, 9)
+    else:
+        return (10, 11, 12)
+
+    # OK
+    if a == "foo":
+        return "bar"
+    elif a == "bar":
+        return baz()
+    elif a == "boo":
+        return "ooh"
+    else:
+        return 42
+
+    # OK
+    if a == b"one":
+        return 1
+    elif b == b"two":
+        return 2
+    elif a == b"three":
+        return 3
+
+    # SIM116
+    if func_name == "create":
+        return "A"
+    elif func_name == "modify":
+        return "M"
+    elif func_name == "remove":
+        return "D"
+    elif func_name == "move":
+        return "MV"
+
+    # OK
+    def no_return_in_else(platform):
+        if platform == "linux":
+            return "auditwheel repair -w {dest_dir} {wheel}"
+        elif platform == "macos":
+            return "delocate-wheel --require-archs {delocate_archs} -w {dest_dir} -v {wheel}"
+        elif platform == "windows":
+            return ""
+        else:
+            msg = f"Unknown platform: {platform!r}"
+            raise ValueError(msg)
--- a/crates/ruff_linter/resources/test/fixtures/flake8_type_checking/TC008.py
+++ b/crates/ruff_linter/resources/test/fixtures/flake8_type_checking/TC008.py
@@ -50,3 +50,23 @@ class Baz:
    class Nested:
        a: TypeAlias = 'Baz'  # OK
        type A = 'Baz'  # TC008
+
+# O should have parenthesis added
+o: TypeAlias = """int
+| None"""
+type O = """int
+| None"""
+
+# P, Q, and R should not have parenthesis added
+p: TypeAlias = ("""int
+| None""")
+type P = ("""int
+| None""")
+
+q: TypeAlias = """(int
+| None)"""
+type Q = """(int
+| None)"""
+
+r: TypeAlias = """int | None"""
+type R = """int | None"""
--- a/crates/ruff_linter/resources/test/fixtures/flake8_type_checking/whitespace.py
+++ b/crates/ruff_linter/resources/test/fixtures/flake8_type_checking/whitespace.py
@@ -0,0 +1,6 @@
+# Regression test for: https://github.com/astral-sh/ruff/issues/19175
+# there is a (potentially invisible) unicode formfeed character (000C) between `TYPE_CHECKING` and the backslash
+from typing import TYPE_CHECKING\
+
+if TYPE_CHECKING: import builtins
+builtins.print("!")
--- a/crates/ruff_linter/resources/test/fixtures/flake8_use_pathlib/PTH203.py
+++ b/crates/ruff_linter/resources/test/fixtures/flake8_use_pathlib/PTH203.py
@@ -1,4 +1,4 @@
-import os.path
+import os.path, pathlib
 from pathlib import Path
 from os.path import getatime

@@ -10,3 +10,26 @@ os.path.getatime(Path("filename"))
 getatime("filename")
 getatime(b"filename")
 getatime(Path("filename"))
+
+
+file = __file__
+
+os.path.getatime(file)
+os.path.getatime(filename="filename")
+os.path.getatime(filename=Path("filename"))
+
+os.path.getatime(  # comment 1
+    # comment 2
+    "filename"  # comment 3
+    # comment 4
+    ,  # comment 5
+    # comment 6
+)  # comment 7
+
+os.path.getatime("file" + "name")
+
+getatime(Path("filename").resolve())
+
+os.path.getatime(pathlib.Path("filename"))
+
+getatime(Path("dir") / "file.txt")
--- a/crates/ruff_linter/resources/test/fixtures/pycodestyle/E27.py
+++ b/crates/ruff_linter/resources/test/fixtures/pycodestyle/E27.py
@@ -81,4 +81,5 @@ match(foo):
 # https://github.com/astral-sh/ruff/issues/12094
 pass;

-yield, x
+def foo():
+    yield, x
--- a/crates/ruff_linter/resources/test/fixtures/pyupgrade/UP008.py
+++ b/crates/ruff_linter/resources/test/fixtures/pyupgrade/UP008.py
@@ -125,3 +125,19 @@ class ClassForCommentEnthusiasts(BaseClass):
            self
            # also a comment
        ).f()
+
+
+# Issue #19096: super calls with keyword arguments should emit diagnostic but not be fixed
+class Ord(int):
+    def __len__(self):
+        return super(Ord, self, uhoh=True, **{"error": True}).bit_length()
+
+class ExampleWithKeywords:
+    def method1(self):
+        super(ExampleWithKeywords, self, invalid=True).some_method()  # Should emit diagnostic but NOT be fixed
+    
+    def method2(self):
+        super(ExampleWithKeywords, self, **{"kwarg": "value"}).some_method()  # Should emit diagnostic but NOT be fixed
+    
+    def method3(self):
+        super(ExampleWithKeywords, self).some_method()  # Should be fixed - no keywords
--- a/crates/ruff_linter/resources/test/fixtures/ruff/RUF009_attrs.py
+++ b/crates/ruff_linter/resources/test/fixtures/ruff/RUF009_attrs.py
@@ -125,3 +125,20 @@ class J:
 class K:
    f: F = F()
    g: G = G()
+
+
+# Regression test for https://github.com/astral-sh/ruff/issues/19014
+# These are all valid field calls and should not cause diagnostics.
+@attr.define
+class TestAttrField:
+    attr_field_factory: list[int] = attr.field(factory=list)
+    attr_field_default: list[int] = attr.field(default=attr.Factory(list))
+    attr_factory: list[int] = attr.Factory(list)
+    attr_ib: list[int] = attr.ib(factory=list)
+    attr_attr: list[int] = attr.attr(factory=list)
+    attr_attrib: list[int] = attr.attrib(factory=list)
+
+
+@attr.attributes
+class TestAttrAttributes:
+    x: list[int] = list()  # RUF009
--- a/crates/ruff_linter/src/checkers/ast/analyze/bindings.rs
+++ b/crates/ruff_linter/src/checkers/ast/analyze/bindings.rs
@@ -4,8 +4,8 @@ use crate::Fix;
 use crate::checkers::ast::Checker;
 use crate::codes::Rule;
 use crate::rules::{
-    flake8_import_conventions, flake8_pyi, flake8_pytest_style, flake8_type_checking, pyflakes,
-    pylint, pyupgrade, refurb, ruff,
+    flake8_import_conventions, flake8_pyi, flake8_pytest_style, flake8_return,
+    flake8_type_checking, pyflakes, pylint, pyupgrade, refurb, ruff,
 };

 /// Run lint rules over the [`Binding`]s.
@@ -25,11 +25,20 @@ pub(crate) fn bindings(checker: &Checker) {
        Rule::ForLoopWrites,
        Rule::CustomTypeVarForSelf,
        Rule::PrivateTypeParameter,
+        Rule::UnnecessaryAssign,
    ]) {
        return;
    }

    for (binding_id, binding) in checker.semantic.bindings.iter_enumerated() {
+        if checker.is_rule_enabled(Rule::UnnecessaryAssign) {
+            if binding.kind.is_function_definition() {
+                flake8_return::rules::unnecessary_assign(
+                    checker,
+                    binding.statement(checker.semantic()).unwrap(),
+                );
+            }
+        }
        if checker.is_rule_enabled(Rule::UnusedVariable) {
            if binding.kind.is_bound_exception()
                && binding.is_unused()
--- a/crates/ruff_linter/src/checkers/ast/analyze/expression.rs
+++ b/crates/ruff_linter/src/checkers/ast/analyze/expression.rs
@@ -7,7 +7,9 @@ use ruff_python_semantic::analyze::typing;
 use ruff_text_size::Ranged;

 use crate::checkers::ast::Checker;
-use crate::preview::is_optional_as_none_in_union_enabled;
+use crate::preview::{
+    is_assert_raises_exception_call_enabled, is_optional_as_none_in_union_enabled,
+};
 use crate::registry::Rule;
 use crate::rules::{
    airflow, flake8_2020, flake8_async, flake8_bandit, flake8_boolean_trap, flake8_bugbear,
@@ -1037,46 +1039,84 @@ pub(crate) fn expression(expr: &Expr, checker: &Checker) {
                flake8_simplify::rules::zip_dict_keys_and_values(checker, call);
            }
            if checker.any_rule_enabled(&[
-                Rule::OsPathAbspath,
                Rule::OsChmod,
                Rule::OsMkdir,
                Rule::OsMakedirs,
                Rule::OsRename,
                Rule::OsReplace,
-                Rule::OsRmdir,
-                Rule::OsRemove,
-                Rule::OsUnlink,
                Rule::OsGetcwd,
-                Rule::OsPathExists,
-                Rule::OsPathExpanduser,
-                Rule::OsPathIsdir,
-                Rule::OsPathIsfile,
-                Rule::OsPathIslink,
-                Rule::OsReadlink,
                Rule::OsStat,
-                Rule::OsPathIsabs,
                Rule::OsPathJoin,
-                Rule::OsPathBasename,
-                Rule::OsPathDirname,
                Rule::OsPathSamefile,
                Rule::OsPathSplitext,
                Rule::BuiltinOpen,
                Rule::PyPath,
-                Rule::OsPathGetatime,
-                Rule::OsPathGetmtime,
-                Rule::OsPathGetctime,
                Rule::Glob,
                Rule::OsListdir,
                Rule::OsSymlink,
            ]) {
                flake8_use_pathlib::rules::replaceable_by_pathlib(checker, call);
            }
-            if checker.is_rule_enabled(Rule::OsPathGetsize) {
-                flake8_use_pathlib::rules::os_path_getsize(checker, call);
-            }
-            if checker.is_rule_enabled(Rule::PathConstructorCurrentDirectory) {
-                flake8_use_pathlib::rules::path_constructor_current_directory(checker, call);
+            if let Some(qualified_name) = checker.semantic().resolve_qualified_name(&call.func) {
+                let segments = qualified_name.segments();
+                if checker.is_rule_enabled(Rule::OsPathGetsize) {
+                    flake8_use_pathlib::rules::os_path_getsize(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsPathGetatime) {
+                    flake8_use_pathlib::rules::os_path_getatime(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsPathGetctime) {
+                    flake8_use_pathlib::rules::os_path_getctime(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsPathGetmtime) {
+                    flake8_use_pathlib::rules::os_path_getmtime(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsPathAbspath) {
+                    flake8_use_pathlib::rules::os_path_abspath(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsRmdir) {
+                    flake8_use_pathlib::rules::os_rmdir(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsRemove) {
+                    flake8_use_pathlib::rules::os_remove(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsUnlink) {
+                    flake8_use_pathlib::rules::os_unlink(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsPathExists) {
+                    flake8_use_pathlib::rules::os_path_exists(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsPathExpanduser) {
+                    flake8_use_pathlib::rules::os_path_expanduser(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsPathBasename) {
+                    flake8_use_pathlib::rules::os_path_basename(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsPathDirname) {
+                    flake8_use_pathlib::rules::os_path_dirname(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsPathIsabs) {
+                    flake8_use_pathlib::rules::os_path_isabs(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsPathIsdir) {
+                    flake8_use_pathlib::rules::os_path_isdir(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsPathIsfile) {
+                    flake8_use_pathlib::rules::os_path_isfile(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsPathIslink) {
+                    flake8_use_pathlib::rules::os_path_islink(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsReadlink) {
+                    flake8_use_pathlib::rules::os_readlink(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::PathConstructorCurrentDirectory) {
+                    flake8_use_pathlib::rules::path_constructor_current_directory(
+                        checker, call, segments,
+                    );
+                }
            }
+
            if checker.is_rule_enabled(Rule::OsSepSplit) {
                flake8_use_pathlib::rules::os_sep_split(checker, call);
            }
@@ -1230,6 +1270,11 @@ pub(crate) fn expression(expr: &Expr, checker: &Checker) {
            if checker.is_rule_enabled(Rule::NonOctalPermissions) {
                ruff::rules::non_octal_permissions(checker, call);
            }
+            if checker.is_rule_enabled(Rule::AssertRaisesException)
+                && is_assert_raises_exception_call_enabled(checker.settings())
+            {
+                flake8_bugbear::rules::assert_raises_exception_call(checker, call);
+            }
        }
        Expr::Dict(dict) => {
            if checker.any_rule_enabled(&[
--- a/crates/ruff_linter/src/checkers/ast/analyze/statement.rs
+++ b/crates/ruff_linter/src/checkers/ast/analyze/statement.rs
@@ -207,7 +207,6 @@ pub(crate) fn statement(stmt: &Stmt, checker: &mut Checker) {
                Rule::UnnecessaryReturnNone,
                Rule::ImplicitReturnValue,
                Rule::ImplicitReturn,
-                Rule::UnnecessaryAssign,
                Rule::SuperfluousElseReturn,
                Rule::SuperfluousElseRaise,
                Rule::SuperfluousElseContinue,
--- a/crates/ruff_linter/src/checkers/ast/mod.rs
+++ b/crates/ruff_linter/src/checkers/ast/mod.rs
@@ -28,6 +28,7 @@ use itertools::Itertools;
 use log::debug;
 use rustc_hash::{FxHashMap, FxHashSet};

+use ruff_db::diagnostic::Diagnostic;
 use ruff_diagnostics::{Applicability, Fix, IsolationLevel};
 use ruff_notebook::{CellOffsets, NotebookIndex};
 use ruff_python_ast::helpers::{collect_import_from_member, is_docstring_stmt, to_module_path};
@@ -74,7 +75,7 @@ use crate::rules::pylint::rules::{AwaitOutsideAsync, LoadBeforeGlobalDeclaration
 use crate::rules::{flake8_pyi, flake8_type_checking, pyflakes, pyupgrade};
 use crate::settings::rule_table::RuleTable;
 use crate::settings::{LinterSettings, TargetVersion, flags};
-use crate::{Edit, OldDiagnostic, Violation};
+use crate::{Edit, Violation};
 use crate::{Locator, docstrings, noqa};

 mod analyze;
@@ -388,7 +389,7 @@ impl<'a> Checker<'a> {

    /// Return a [`DiagnosticGuard`] for reporting a diagnostic.
    ///
-    /// The guard derefs to an [`OldDiagnostic`], so it can be used to further modify the diagnostic
+    /// The guard derefs to a [`Diagnostic`], so it can be used to further modify the diagnostic
    /// before it is added to the collection in the checker on `Drop`.
    pub(crate) fn report_diagnostic<'chk, T: Violation>(
        &'chk self,
@@ -401,7 +402,7 @@ impl<'a> Checker<'a> {
    /// Return a [`DiagnosticGuard`] for reporting a diagnostic if the corresponding rule is
    /// enabled.
    ///
-    /// The guard derefs to an [`OldDiagnostic`], so it can be used to further modify the diagnostic
+    /// The guard derefs to a [`Diagnostic`], so it can be used to further modify the diagnostic
    /// before it is added to the collection in the checker on `Drop`.
    pub(crate) fn report_diagnostic_if_enabled<'chk, T: Violation>(
        &'chk self,
@@ -3116,9 +3117,9 @@ pub(crate) fn check_ast(
 /// A type for collecting diagnostics in a given file.
 ///
 /// [`LintContext::report_diagnostic`] can be used to obtain a [`DiagnosticGuard`], which will push
-/// a [`Violation`] to the contained [`OldDiagnostic`] collection on `Drop`.
+/// a [`Violation`] to the contained [`Diagnostic`] collection on `Drop`.
 pub(crate) struct LintContext<'a> {
-    diagnostics: RefCell<Vec<OldDiagnostic>>,
+    diagnostics: RefCell<Vec<Diagnostic>>,
    source_file: SourceFile,
    rules: RuleTable,
    settings: &'a LinterSettings,
@@ -3126,7 +3127,7 @@ pub(crate) struct LintContext<'a> {

 impl<'a> LintContext<'a> {
    /// Create a new collector with the given `source_file` and an empty collection of
-    /// `OldDiagnostic`s.
+    /// `Diagnostic`s.
    pub(crate) fn new(path: &Path, contents: &str, settings: &'a LinterSettings) -> Self {
        let source_file =
            SourceFileBuilder::new(path.to_string_lossy().as_ref(), contents).finish();
@@ -3147,7 +3148,7 @@ impl<'a> LintContext<'a> {

    /// Return a [`DiagnosticGuard`] for reporting a diagnostic.
    ///
-    /// The guard derefs to an [`OldDiagnostic`], so it can be used to further modify the diagnostic
+    /// The guard derefs to a [`Diagnostic`], so it can be used to further modify the diagnostic
    /// before it is added to the collection in the context on `Drop`.
    pub(crate) fn report_diagnostic<'chk, T: Violation>(
        &'chk self,
@@ -3156,7 +3157,7 @@ impl<'a> LintContext<'a> {
    ) -> DiagnosticGuard<'chk, 'a> {
        DiagnosticGuard {
            context: self,
-            diagnostic: Some(OldDiagnostic::new(kind, range, &self.source_file)),
+            diagnostic: Some(kind.into_diagnostic(range, &self.source_file)),
            rule: T::rule(),
        }
    }
@@ -3164,7 +3165,7 @@ impl<'a> LintContext<'a> {
    /// Return a [`DiagnosticGuard`] for reporting a diagnostic if the corresponding rule is
    /// enabled.
    ///
-    /// The guard derefs to an [`OldDiagnostic`], so it can be used to further modify the diagnostic
+    /// The guard derefs to a [`Diagnostic`], so it can be used to further modify the diagnostic
    /// before it is added to the collection in the context on `Drop`.
    pub(crate) fn report_diagnostic_if_enabled<'chk, T: Violation>(
        &'chk self,
@@ -3175,7 +3176,7 @@ impl<'a> LintContext<'a> {
        if self.is_rule_enabled(rule) {
            Some(DiagnosticGuard {
                context: self,
-                diagnostic: Some(OldDiagnostic::new(kind, range, &self.source_file)),
+                diagnostic: Some(kind.into_diagnostic(range, &self.source_file)),
                rule,
            })
        } else {
@@ -3199,17 +3200,17 @@ impl<'a> LintContext<'a> {
    }

    #[inline]
-    pub(crate) fn into_parts(self) -> (Vec<OldDiagnostic>, SourceFile) {
+    pub(crate) fn into_parts(self) -> (Vec<Diagnostic>, SourceFile) {
        (self.diagnostics.into_inner(), self.source_file)
    }

    #[inline]
-    pub(crate) fn as_mut_vec(&mut self) -> &mut Vec<OldDiagnostic> {
+    pub(crate) fn as_mut_vec(&mut self) -> &mut Vec<Diagnostic> {
        self.diagnostics.get_mut()
    }

    #[inline]
-    pub(crate) fn iter(&mut self) -> impl Iterator<Item = &OldDiagnostic> {
+    pub(crate) fn iter(&mut self) -> impl Iterator<Item = &Diagnostic> {
        self.diagnostics.get_mut().iter()
    }
 }
@@ -3227,7 +3228,7 @@ pub(crate) struct DiagnosticGuard<'a, 'b> {
    /// The diagnostic that we want to report.
    ///
    /// This is always `Some` until the `Drop` (or `defuse`) call.
-    diagnostic: Option<OldDiagnostic>,
+    diagnostic: Option<Diagnostic>,
    rule: Rule,
 }

@@ -3253,11 +3254,14 @@ impl DiagnosticGuard<'_, '_> {
    #[inline]
    pub(crate) fn set_fix(&mut self, fix: Fix) {
        if !self.context.rules.should_fix(self.rule) {
-            self.fix = None;
+            self.diagnostic.as_mut().unwrap().remove_fix();
            return;
        }
        let applicability = self.resolve_applicability(&fix);
-        self.fix = Some(fix.with_applicability(applicability));
+        self.diagnostic
+            .as_mut()
+            .unwrap()
+            .set_fix(fix.with_applicability(applicability));
    }

    /// Set the [`Fix`] used to fix the diagnostic, if the provided function returns `Ok`.
@@ -3286,9 +3290,9 @@ impl DiagnosticGuard<'_, '_> {
 }

 impl std::ops::Deref for DiagnosticGuard<'_, '_> {
-    type Target = OldDiagnostic;
+    type Target = Diagnostic;

-    fn deref(&self) -> &OldDiagnostic {
+    fn deref(&self) -> &Diagnostic {
        // OK because `self.diagnostic` is only `None` within `Drop`.
        self.diagnostic.as_ref().unwrap()
    }
@@ -3296,7 +3300,7 @@ impl std::ops::Deref for DiagnosticGuard<'_, '_> {

 /// Return a mutable borrow of the diagnostic in this guard.
 impl std::ops::DerefMut for DiagnosticGuard<'_, '_> {
-    fn deref_mut(&mut self) -> &mut OldDiagnostic {
+    fn deref_mut(&mut self) -> &mut Diagnostic {
        // OK because `self.diagnostic` is only `None` within `Drop`.
        self.diagnostic.as_mut().unwrap()
    }
--- a/crates/ruff_linter/src/checkers/noqa.rs
+++ b/crates/ruff_linter/src/checkers/noqa.rs
@@ -66,9 +66,9 @@ pub(crate) fn check_noqa(
        }

        let noqa_offsets = diagnostic
-            .parent
+            .parent()
            .into_iter()
-            .chain(std::iter::once(diagnostic.start()))
+            .chain(std::iter::once(diagnostic.expect_range().start()))
            .map(|position| noqa_line_for.resolve(position))
            .unique();

--- a/crates/ruff_linter/src/codes.rs
+++ b/crates/ruff_linter/src/codes.rs
@@ -4,6 +4,7 @@
 /// `--select`. For pylint this is e.g. C0414 and E0118 but also C and E01.
 use std::fmt::Formatter;

+use ruff_db::diagnostic::SecondaryCode;
 use strum_macros::EnumIter;

 use crate::registry::Linter;
@@ -52,6 +53,18 @@ impl PartialEq<NoqaCode> for &str {
    }
 }

+impl PartialEq<NoqaCode> for SecondaryCode {
+    fn eq(&self, other: &NoqaCode) -> bool {
+        &self.as_str() == other
+    }
+}
+
+impl PartialEq<SecondaryCode> for NoqaCode {
+    fn eq(&self, other: &SecondaryCode) -> bool {
+        other.eq(self)
+    }
+}
+
 impl serde::Serialize for NoqaCode {
    fn serialize<S>(&self, serializer: S) -> std::result::Result<S::Ok, S::Error>
    where
@@ -906,27 +919,27 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<(RuleGroup, Rule)> {
        (Tryceratops, "401") => (RuleGroup::Stable, rules::tryceratops::rules::VerboseLogMessage),

        // flake8-use-pathlib
-        (Flake8UsePathlib, "100") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsPathAbspath),
+        (Flake8UsePathlib, "100") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsPathAbspath),
        (Flake8UsePathlib, "101") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsChmod),
        (Flake8UsePathlib, "102") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsMkdir),
        (Flake8UsePathlib, "103") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsMakedirs),
        (Flake8UsePathlib, "104") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsRename),
        (Flake8UsePathlib, "105") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsReplace),
-        (Flake8UsePathlib, "106") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsRmdir),
-        (Flake8UsePathlib, "107") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsRemove),
-        (Flake8UsePathlib, "108") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsUnlink),
+        (Flake8UsePathlib, "106") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsRmdir),
+        (Flake8UsePathlib, "107") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsRemove),
+        (Flake8UsePathlib, "108") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsUnlink),
        (Flake8UsePathlib, "109") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsGetcwd),
-        (Flake8UsePathlib, "110") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsPathExists),
-        (Flake8UsePathlib, "111") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsPathExpanduser),
-        (Flake8UsePathlib, "112") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsPathIsdir),
-        (Flake8UsePathlib, "113") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsPathIsfile),
-        (Flake8UsePathlib, "114") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsPathIslink),
-        (Flake8UsePathlib, "115") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsReadlink),
+        (Flake8UsePathlib, "110") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsPathExists),
+        (Flake8UsePathlib, "111") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsPathExpanduser),
+        (Flake8UsePathlib, "112") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsPathIsdir),
+        (Flake8UsePathlib, "113") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsPathIsfile),
+        (Flake8UsePathlib, "114") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsPathIslink),
+        (Flake8UsePathlib, "115") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsReadlink),
        (Flake8UsePathlib, "116") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsStat),
-        (Flake8UsePathlib, "117") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsPathIsabs),
+        (Flake8UsePathlib, "117") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsPathIsabs),
        (Flake8UsePathlib, "118") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsPathJoin),
-        (Flake8UsePathlib, "119") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsPathBasename),
-        (Flake8UsePathlib, "120") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsPathDirname),
+        (Flake8UsePathlib, "119") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsPathBasename),
+        (Flake8UsePathlib, "120") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsPathDirname),
        (Flake8UsePathlib, "121") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsPathSamefile),
        (Flake8UsePathlib, "122") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsPathSplitext),
        (Flake8UsePathlib, "123") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::BuiltinOpen),
--- a/crates/ruff_linter/src/fix/edits.rs
+++ b/crates/ruff_linter/src/fix/edits.rs
@@ -618,7 +618,7 @@ mod tests {
    use crate::fix::edits::{
        add_to_dunder_all, make_redundant_alias, next_stmt_break, trailing_semicolon,
    };
-    use crate::{Edit, Fix, Locator, OldDiagnostic};
+    use crate::{Edit, Fix, Locator, Violation};

    /// Parse the given source using [`Mode::Module`] and return the first statement.
    fn parse_first_stmt(source: &str) -> Result<Stmt> {
@@ -749,12 +749,12 @@ x = 1 \
        let diag = {
            use crate::rules::pycodestyle::rules::MissingNewlineAtEndOfFile;
            let mut iter = edits.into_iter();
-            let mut diagnostic = OldDiagnostic::new(
-                MissingNewlineAtEndOfFile, // The choice of rule here is arbitrary.
+            // The choice of rule here is arbitrary.
+            let mut diagnostic = MissingNewlineAtEndOfFile.into_diagnostic(
                TextRange::default(),
                &SourceFileBuilder::new("<filename>", "<code>").finish(),
            );
-            diagnostic.fix = Some(Fix::safe_edits(
+            diagnostic.set_fix(Fix::safe_edits(
                iter.next().ok_or(anyhow!("expected edits nonempty"))?,
                iter,
            ));
--- a/crates/ruff_linter/src/fix/mod.rs
+++ b/crates/ruff_linter/src/fix/mod.rs
@@ -3,12 +3,12 @@ use std::collections::BTreeSet;
 use itertools::Itertools;
 use rustc_hash::FxHashSet;

+use ruff_db::diagnostic::Diagnostic;
 use ruff_diagnostics::{IsolationLevel, SourceMap};
 use ruff_text_size::{Ranged, TextLen, TextRange, TextSize};

 use crate::Locator;
 use crate::linter::FixTable;
-use crate::message::OldDiagnostic;
 use crate::registry::Rule;
 use crate::settings::types::UnsafeFixes;
 use crate::{Edit, Fix};
@@ -28,7 +28,7 @@ pub(crate) struct FixResult {

 /// Fix errors in a file, and write the fixed source code to disk.
 pub(crate) fn fix_file(
-    diagnostics: &[OldDiagnostic],
+    diagnostics: &[Diagnostic],
    locator: &Locator,
    unsafe_fixes: UnsafeFixes,
 ) -> Option<FixResult> {
@@ -52,7 +52,7 @@ pub(crate) fn fix_file(

 /// Apply a series of fixes.
 fn apply_fixes<'a>(
-    diagnostics: impl Iterator<Item = &'a OldDiagnostic>,
+    diagnostics: impl Iterator<Item = &'a Diagnostic>,
    locator: &'a Locator<'a>,
 ) -> FixResult {
    let mut output = String::with_capacity(locator.len());
@@ -172,26 +172,25 @@ mod tests {
    use ruff_source_file::SourceFileBuilder;
    use ruff_text_size::{Ranged, TextSize};

-    use crate::Locator;
-    use crate::OldDiagnostic;
    use crate::fix::{FixResult, apply_fixes};
    use crate::rules::pycodestyle::rules::MissingNewlineAtEndOfFile;
    use crate::{Edit, Fix};
+    use crate::{Locator, Violation};
+    use ruff_db::diagnostic::Diagnostic;

    fn create_diagnostics(
        filename: &str,
        source: &str,
        edit: impl IntoIterator<Item = Edit>,
-    ) -> Vec<OldDiagnostic> {
+    ) -> Vec<Diagnostic> {
        edit.into_iter()
            .map(|edit| {
                // The choice of rule here is arbitrary.
-                let mut diagnostic = OldDiagnostic::new(
-                    MissingNewlineAtEndOfFile,
+                let mut diagnostic = MissingNewlineAtEndOfFile.into_diagnostic(
                    edit.range(),
                    &SourceFileBuilder::new(filename, source).finish(),
                );
-                diagnostic.fix = Some(Fix::safe_edit(edit));
+                diagnostic.set_fix(Fix::safe_edit(edit));
                diagnostic
            })
            .collect()
--- a/crates/ruff_linter/src/importer/insertion.rs
+++ b/crates/ruff_linter/src/importer/insertion.rs
@@ -5,6 +5,7 @@ use ruff_python_ast::Stmt;
 use ruff_python_ast::helpers::is_docstring_stmt;
 use ruff_python_codegen::Stylist;
 use ruff_python_parser::{TokenKind, Tokens};
+use ruff_python_trivia::is_python_whitespace;
 use ruff_python_trivia::{PythonWhitespace, textwrap::indent};
 use ruff_source_file::{LineRanges, UniversalNewlineIterator};
 use ruff_text_size::{Ranged, TextSize};
@@ -306,7 +307,7 @@ fn match_semicolon(s: &str) -> Option<TextSize> {
 fn match_continuation(s: &str) -> Option<TextSize> {
    for (offset, c) in s.char_indices() {
        match c {
-            ' ' | '\t' => continue,
+            _ if is_python_whitespace(c) => continue,
            '\\' => return Some(TextSize::try_from(offset).unwrap()),
            _ => break,
        }
--- a/crates/ruff_linter/src/lib.rs
+++ b/crates/ruff_linter/src/lib.rs
@@ -14,7 +14,6 @@ pub use rule_selector::RuleSelector;
 pub use rule_selector::clap_completion::RuleSelectorParser;
 pub use rules::pycodestyle::rules::IOError;

-pub use message::OldDiagnostic;
 pub(crate) use ruff_diagnostics::{Applicability, Edit, Fix};
 pub use violation::{AlwaysFixableViolation, FixAvailability, Violation, ViolationMetadata};

--- a/crates/ruff_linter/src/linter.rs
+++ b/crates/ruff_linter/src/linter.rs
@@ -7,15 +7,14 @@ use itertools::Itertools;
 use ruff_python_parser::semantic_errors::SemanticSyntaxError;
 use rustc_hash::FxBuildHasher;

+use ruff_db::diagnostic::{Diagnostic, SecondaryCode};
 use ruff_notebook::Notebook;
 use ruff_python_ast::{ModModule, PySourceType, PythonVersion};
 use ruff_python_codegen::Stylist;
 use ruff_python_index::Indexer;
 use ruff_python_parser::{ParseError, ParseOptions, Parsed, UnsupportedSyntaxError};
 use ruff_source_file::SourceFile;
-use ruff_text_size::Ranged;

-use crate::OldDiagnostic;
 use crate::checkers::ast::{LintContext, check_ast};
 use crate::checkers::filesystem::check_file_path;
 use crate::checkers::imports::check_imports;
@@ -25,7 +24,7 @@ use crate::checkers::tokens::check_tokens;
 use crate::directives::Directives;
 use crate::doc_lines::{doc_lines_from_ast, doc_lines_from_tokens};
 use crate::fix::{FixResult, fix_file};
-use crate::message::SecondaryCode;
+use crate::message::create_syntax_error_diagnostic;
 use crate::noqa::add_noqa;
 use crate::package::PackageRoot;
 use crate::preview::is_py314_support_enabled;
@@ -41,7 +40,7 @@ pub(crate) mod float;

 pub struct LinterResult {
    /// A collection of diagnostic messages generated by the linter.
-    pub diagnostics: Vec<OldDiagnostic>,
+    pub diagnostics: Vec<Diagnostic>,
    /// Flag indicating that the parsed source code does not contain any
    /// [`ParseError`]s
    has_valid_syntax: bool,
@@ -145,7 +144,7 @@ pub struct FixerResult<'a> {
    pub fixed: FixTable,
 }

-/// Generate [`OldDiagnostic`]s from the source code contents at the given `Path`.
+/// Generate [`Diagnostic`]s from the source code contents at the given `Path`.
 #[expect(clippy::too_many_arguments)]
 pub fn check_path(
    path: &Path,
@@ -160,7 +159,7 @@ pub fn check_path(
    source_type: PySourceType,
    parsed: &Parsed<ModModule>,
    target_version: TargetVersion,
-) -> Vec<OldDiagnostic> {
+) -> Vec<Diagnostic> {
    // Aggregate all diagnostics.
    let mut context = LintContext::new(path, locator.contents(), settings);

@@ -382,7 +381,7 @@ pub fn check_path(
    if !parsed.has_valid_syntax() {
        // Avoid fixing in case the source code contains syntax errors.
        for diagnostic in &mut diagnostics {
-            diagnostic.fix = None;
+            diagnostic.remove_fix();
        }
    }

@@ -393,7 +392,6 @@ pub fn check_path(
        parsed.errors(),
        syntax_errors,
        &semantic_syntax_errors,
-        locator,
        directives,
        &source_file,
    )
@@ -459,7 +457,7 @@ pub fn add_noqa_to_path(
    )
 }

-/// Generate an [`OldDiagnostic`] for each diagnostic triggered by the given source code.
+/// Generate a [`Diagnostic`] for each diagnostic triggered by the given source code.
 pub fn lint_only(
    path: &Path,
    package: Option<PackageRoot<'_>>,
@@ -516,7 +514,7 @@ pub fn lint_only(

    LinterResult {
        has_valid_syntax: parsed.has_valid_syntax(),
-        has_no_syntax_errors: !diagnostics.iter().any(OldDiagnostic::is_syntax_error),
+        has_no_syntax_errors: !diagnostics.iter().any(Diagnostic::is_invalid_syntax),
        diagnostics,
    }
 }
@@ -525,30 +523,32 @@ pub fn lint_only(
 ///
 /// Also use `directives` to attach noqa offsets to lint diagnostics.
 fn diagnostics_to_messages(
-    diagnostics: Vec<OldDiagnostic>,
+    diagnostics: Vec<Diagnostic>,
    parse_errors: &[ParseError],
    unsupported_syntax_errors: &[UnsupportedSyntaxError],
    semantic_syntax_errors: &[SemanticSyntaxError],
-    locator: &Locator,
    directives: &Directives,
    source_file: &SourceFile,
-) -> Vec<OldDiagnostic> {
+) -> Vec<Diagnostic> {
    parse_errors
        .iter()
        .map(|parse_error| {
-            OldDiagnostic::from_parse_error(parse_error, locator, source_file.clone())
+            create_syntax_error_diagnostic(source_file.clone(), &parse_error.error, parse_error)
        })
        .chain(unsupported_syntax_errors.iter().map(|syntax_error| {
-            OldDiagnostic::from_unsupported_syntax_error(syntax_error, source_file.clone())
+            create_syntax_error_diagnostic(source_file.clone(), syntax_error, syntax_error)
        }))
        .chain(
            semantic_syntax_errors
                .iter()
-                .map(|error| OldDiagnostic::from_semantic_syntax_error(error, source_file.clone())),
+                .map(|error| create_syntax_error_diagnostic(source_file.clone(), error, error)),
        )
-        .chain(diagnostics.into_iter().map(|diagnostic| {
-            let noqa_offset = directives.noqa_line_for.resolve(diagnostic.start());
-            diagnostic.with_noqa_offset(noqa_offset)
+        .chain(diagnostics.into_iter().map(|mut diagnostic| {
+            let noqa_offset = directives
+                .noqa_line_for
+                .resolve(diagnostic.expect_range().start());
+            diagnostic.set_noqa_offset(noqa_offset);
+            diagnostic
        }))
        .collect()
 }
@@ -629,7 +629,7 @@ pub fn lint_fix<'a>(

        if iterations == 0 {
            has_valid_syntax = parsed.has_valid_syntax();
-            has_no_syntax_errors = !diagnostics.iter().any(OldDiagnostic::is_syntax_error);
+            has_no_syntax_errors = !diagnostics.iter().any(Diagnostic::is_invalid_syntax);
        } else {
            // If the source code had no syntax errors on the first pass, but
            // does on a subsequent pass, then we've introduced a
@@ -687,8 +687,8 @@ where
 }

 #[expect(clippy::print_stderr)]
-fn report_failed_to_converge_error(path: &Path, transformed: &str, diagnostics: &[OldDiagnostic]) {
-    let codes = collect_rule_codes(diagnostics.iter().filter_map(OldDiagnostic::secondary_code));
+fn report_failed_to_converge_error(path: &Path, transformed: &str, diagnostics: &[Diagnostic]) {
+    let codes = collect_rule_codes(diagnostics.iter().filter_map(Diagnostic::secondary_code));
    if cfg!(debug_assertions) {
        eprintln!(
            "{}{} Failed to converge after {} iterations in `{}` with rule codes {}:---\n{}\n---",
@@ -806,13 +806,12 @@ mod tests {
    use ruff_python_index::Indexer;
    use ruff_python_parser::ParseOptions;
    use ruff_python_trivia::textwrap::dedent;
-    use ruff_text_size::Ranged;
    use test_case::test_case;

+    use ruff_db::diagnostic::Diagnostic;
    use ruff_notebook::{Notebook, NotebookError};

    use crate::linter::check_path;
-    use crate::message::OldDiagnostic;
    use crate::registry::Rule;
    use crate::settings::LinterSettings;
    use crate::source_kind::SourceKind;
@@ -970,7 +969,7 @@ mod tests {

    /// Wrapper around `test_contents_syntax_errors` for testing a snippet of code instead of a
    /// file.
-    fn test_snippet_syntax_errors(contents: &str, settings: &LinterSettings) -> Vec<OldDiagnostic> {
+    fn test_snippet_syntax_errors(contents: &str, settings: &LinterSettings) -> Vec<Diagnostic> {
        let contents = dedent(contents);
        test_contents_syntax_errors(
            &SourceKind::Python(contents.to_string()),
@@ -985,7 +984,7 @@ mod tests {
        source_kind: &SourceKind,
        path: &Path,
        settings: &LinterSettings,
-    ) -> Vec<OldDiagnostic> {
+    ) -> Vec<Diagnostic> {
        let source_type = PySourceType::from(path);
        let target_version = settings.resolve_target_version(path);
        let options =
@@ -1016,7 +1015,7 @@ mod tests {
            &parsed,
            target_version,
        );
-        diagnostics.sort_by_key(Ranged::start);
+        diagnostics.sort_by_key(|diagnostic| diagnostic.expect_range().start());
        diagnostics
    }

--- a/crates/ruff_linter/src/logging.rs
+++ b/crates/ruff_linter/src/logging.rs
@@ -1,4 +1,4 @@
-use std::fmt::{Display, Formatter, Write};
+use std::fmt::{Display, Formatter};
 use std::path::{Path, PathBuf};
 use std::sync::{LazyLock, Mutex};

@@ -6,7 +6,7 @@ use anyhow::Result;
 use colored::Colorize;
 use fern;
 use log::Level;
-use ruff_python_parser::{ParseError, ParseErrorType};
+use ruff_python_parser::ParseError;
 use rustc_hash::FxHashSet;

 use ruff_source_file::{LineColumn, LineIndex, OneIndexed, SourceCode};
@@ -248,7 +248,7 @@ impl Display for DisplayParseError {
                    row = location.line,
                    column = location.column,
                    colon = ":".cyan(),
-                    inner = &DisplayParseErrorType(&self.error.error)
+                    inner = self.error.error
                )
            }
            ErrorLocation::Cell(cell, location) => {
@@ -259,27 +259,13 @@ impl Display for DisplayParseError {
                    row = location.line,
                    column = location.column,
                    colon = ":".cyan(),
-                    inner = &DisplayParseErrorType(&self.error.error)
+                    inner = self.error.error
                )
            }
        }
    }
 }

-pub(crate) struct DisplayParseErrorType<'a>(&'a ParseErrorType);
-
-impl<'a> DisplayParseErrorType<'a> {
-    pub(crate) fn new(error: &'a ParseErrorType) -> Self {
-        Self(error)
-    }
-}
-
-impl Display for DisplayParseErrorType<'_> {
-    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
-        write!(f, "{}", TruncateAtNewline(&self.0))
-    }
-}
-
 #[derive(Debug)]
 enum ErrorLocation {
    /// The error occurred in a Python file.
@@ -288,44 +274,6 @@ enum ErrorLocation {
    Cell(OneIndexed, LineColumn),
 }

-/// Truncates the display text before the first newline character to avoid line breaks.
-struct TruncateAtNewline<'a>(&'a dyn Display);
-
-impl Display for TruncateAtNewline<'_> {
-    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
-        struct TruncateAdapter<'a> {
-            inner: &'a mut dyn Write,
-            after_new_line: bool,
-        }
-
-        impl Write for TruncateAdapter<'_> {
-            fn write_str(&mut self, s: &str) -> std::fmt::Result {
-                if self.after_new_line {
-                    Ok(())
-                } else {
-                    if let Some(end) = s.find(['\n', '\r']) {
-                        self.inner.write_str(&s[..end])?;
-                        self.inner.write_str("\u{23ce}...")?;
-                        self.after_new_line = true;
-                        Ok(())
-                    } else {
-                        self.inner.write_str(s)
-                    }
-                }
-            }
-        }
-
-        write!(
-            TruncateAdapter {
-                inner: f,
-                after_new_line: false,
-            },
-            "{}",
-            self.0
-        )
-    }
-}
-
 #[cfg(test)]
 mod tests {
    use crate::logging::LogLevel;
--- a/crates/ruff_linter/src/message/azure.rs
+++ b/crates/ruff_linter/src/message/azure.rs
@@ -1,8 +1,9 @@
 use std::io::Write;

+use ruff_db::diagnostic::Diagnostic;
 use ruff_source_file::LineColumn;

-use crate::message::{Emitter, EmitterContext, OldDiagnostic};
+use crate::message::{Emitter, EmitterContext};

 /// Generate error logging commands for Azure Pipelines format.
 /// See [documentation](https://learn.microsoft.com/en-us/azure/devops/pipelines/scripts/logging-commands?view=azure-devops&tabs=bash#logissue-log-an-error-or-warning)
@@ -13,23 +14,23 @@ impl Emitter for AzureEmitter {
    fn emit(
        &mut self,
        writer: &mut dyn Write,
-        diagnostics: &[OldDiagnostic],
+        diagnostics: &[Diagnostic],
        context: &EmitterContext,
    ) -> anyhow::Result<()> {
        for diagnostic in diagnostics {
-            let location = if context.is_notebook(&diagnostic.filename()) {
+            let filename = diagnostic.expect_ruff_filename();
+            let location = if context.is_notebook(&filename) {
                // We can't give a reasonable location for the structured formats,
                // so we show one that's clearly a fallback
                LineColumn::default()
            } else {
-                diagnostic.compute_start_location()
+                diagnostic.expect_ruff_start_location()
            };

            writeln!(
                writer,
                "##vso[task.logissue type=error\
                        ;sourcepath={filename};linenumber={line};columnnumber={col};{code}]{body}",
-                filename = diagnostic.filename(),
                line = location.line,
                col = location.column,
                code = diagnostic
--- a/crates/ruff_linter/src/message/diff.rs
+++ b/crates/ruff_linter/src/message/diff.rs
@@ -2,13 +2,12 @@ use std::fmt::{Display, Formatter};
 use std::num::NonZeroUsize;

 use colored::{Color, ColoredString, Colorize, Styles};
-
-use ruff_text_size::{Ranged, TextRange, TextSize};
 use similar::{ChangeTag, TextDiff};

+use ruff_db::diagnostic::Diagnostic;
 use ruff_source_file::{OneIndexed, SourceFile};
+use ruff_text_size::{Ranged, TextRange, TextSize};

-use crate::message::OldDiagnostic;
 use crate::text_helpers::ShowNonprinting;
 use crate::{Applicability, Fix};

@@ -26,9 +25,9 @@ pub(super) struct Diff<'a> {
 }

 impl<'a> Diff<'a> {
-    pub(crate) fn from_message(message: &'a OldDiagnostic) -> Option<Diff<'a>> {
+    pub(crate) fn from_message(message: &'a Diagnostic) -> Option<Diff<'a>> {
        message.fix().map(|fix| Diff {
-            source_code: message.source_file(),
+            source_code: message.expect_ruff_source_file(),
            fix,
        })
    }
--- a/crates/ruff_linter/src/message/github.rs
+++ b/crates/ruff_linter/src/message/github.rs
@@ -1,9 +1,10 @@
 use std::io::Write;

+use ruff_db::diagnostic::Diagnostic;
 use ruff_source_file::LineColumn;

 use crate::fs::relativize_path;
-use crate::message::{Emitter, EmitterContext, OldDiagnostic};
+use crate::message::{Emitter, EmitterContext};

 /// Generate error workflow command in GitHub Actions format.
 /// See: [GitHub documentation](https://docs.github.com/en/actions/reference/workflow-commands-for-github-actions#setting-an-error-message)
@@ -14,12 +15,13 @@ impl Emitter for GithubEmitter {
    fn emit(
        &mut self,
        writer: &mut dyn Write,
-        diagnostics: &[OldDiagnostic],
+        diagnostics: &[Diagnostic],
        context: &EmitterContext,
    ) -> anyhow::Result<()> {
        for diagnostic in diagnostics {
-            let source_location = diagnostic.compute_start_location();
-            let location = if context.is_notebook(&diagnostic.filename()) {
+            let source_location = diagnostic.expect_ruff_start_location();
+            let filename = diagnostic.expect_ruff_filename();
+            let location = if context.is_notebook(&filename) {
                // We can't give a reasonable location for the structured formats,
                // so we show one that's clearly a fallback
                LineColumn::default()
@@ -27,7 +29,7 @@ impl Emitter for GithubEmitter {
                source_location
            };

-            let end_location = diagnostic.compute_end_location();
+            let end_location = diagnostic.expect_ruff_end_location();

            write!(
                writer,
@@ -35,7 +37,7 @@ impl Emitter for GithubEmitter {
                code = diagnostic
                    .secondary_code()
                    .map_or_else(String::new, |code| format!(" ({code})")),
-                file = diagnostic.filename(),
+                file = filename,
                row = source_location.line,
                column = source_location.column,
                end_row = end_location.line,
@@ -45,7 +47,7 @@ impl Emitter for GithubEmitter {
            write!(
                writer,
                "{path}:{row}:{column}:",
-                path = relativize_path(&*diagnostic.filename()),
+                path = relativize_path(&filename),
                row = location.line,
                column = location.column,
            )?;
--- a/crates/ruff_linter/src/message/gitlab.rs
+++ b/crates/ruff_linter/src/message/gitlab.rs
@@ -7,8 +7,10 @@ use serde::ser::SerializeSeq;
 use serde::{Serialize, Serializer};
 use serde_json::json;

+use ruff_db::diagnostic::Diagnostic;
+
 use crate::fs::{relativize_path, relativize_path_to};
-use crate::message::{Emitter, EmitterContext, OldDiagnostic};
+use crate::message::{Emitter, EmitterContext};

 /// Generate JSON with violations in GitLab CI format
 //  https://docs.gitlab.com/ee/ci/testing/code_quality.html#implement-a-custom-tool
@@ -28,7 +30,7 @@ impl Emitter for GitlabEmitter {
    fn emit(
        &mut self,
        writer: &mut dyn Write,
-        diagnostics: &[OldDiagnostic],
+        diagnostics: &[Diagnostic],
        context: &EmitterContext,
    ) -> anyhow::Result<()> {
        serde_json::to_writer_pretty(
@@ -45,7 +47,7 @@ impl Emitter for GitlabEmitter {
 }

 struct SerializedMessages<'a> {
-    diagnostics: &'a [OldDiagnostic],
+    diagnostics: &'a [Diagnostic],
    context: &'a EmitterContext<'a>,
    project_dir: Option<&'a str>,
 }
@@ -59,10 +61,11 @@ impl Serialize for SerializedMessages<'_> {
        let mut fingerprints = HashSet::<u64>::with_capacity(self.diagnostics.len());

        for diagnostic in self.diagnostics {
-            let start_location = diagnostic.compute_start_location();
-            let end_location = diagnostic.compute_end_location();
+            let start_location = diagnostic.expect_ruff_start_location();
+            let end_location = diagnostic.expect_ruff_end_location();

-            let lines = if self.context.is_notebook(&diagnostic.filename()) {
+            let filename = diagnostic.expect_ruff_filename();
+            let lines = if self.context.is_notebook(&filename) {
                // We can't give a reasonable location for the structured formats,
                // so we show one that's clearly a fallback
                json!({
@@ -77,8 +80,8 @@ impl Serialize for SerializedMessages<'_> {
            };

            let path = self.project_dir.as_ref().map_or_else(
-                || relativize_path(&*diagnostic.filename()),
-                |project_dir| relativize_path_to(&*diagnostic.filename(), project_dir),
+                || relativize_path(&filename),
+                |project_dir| relativize_path_to(&filename, project_dir),
            );

            let mut message_fingerprint = fingerprint(diagnostic, &path, 0);
@@ -120,7 +123,7 @@ impl Serialize for SerializedMessages<'_> {
 }

 /// Generate a unique fingerprint to identify a violation.
-fn fingerprint(message: &OldDiagnostic, project_path: &str, salt: u64) -> u64 {
+fn fingerprint(message: &Diagnostic, project_path: &str, salt: u64) -> u64 {
    let mut hasher = DefaultHasher::new();

    salt.hash(&mut hasher);
--- a/crates/ruff_linter/src/message/grouped.rs
+++ b/crates/ruff_linter/src/message/grouped.rs
@@ -4,15 +4,14 @@ use std::num::NonZeroUsize;

 use colored::Colorize;

+use ruff_db::diagnostic::Diagnostic;
 use ruff_notebook::NotebookIndex;
 use ruff_source_file::OneIndexed;

 use crate::fs::relativize_path;
 use crate::message::diff::calculate_print_width;
 use crate::message::text::{MessageCodeFrame, RuleCodeAndBody};
-use crate::message::{
-    Emitter, EmitterContext, MessageWithLocation, OldDiagnostic, group_diagnostics_by_filename,
-};
+use crate::message::{Emitter, EmitterContext, MessageWithLocation, group_diagnostics_by_filename};
 use crate::settings::types::UnsafeFixes;

 #[derive(Default)]
@@ -46,7 +45,7 @@ impl Emitter for GroupedEmitter {
    fn emit(
        &mut self,
        writer: &mut dyn Write,
-        diagnostics: &[OldDiagnostic],
+        diagnostics: &[Diagnostic],
        context: &EmitterContext,
    ) -> anyhow::Result<()> {
        for (filename, messages) in group_diagnostics_by_filename(diagnostics) {
@@ -73,7 +72,7 @@ impl Emitter for GroupedEmitter {
                    writer,
                    "{}",
                    DisplayGroupedMessage {
-                        notebook_index: context.notebook_index(&message.filename()),
+                        notebook_index: context.notebook_index(&message.expect_ruff_filename()),
                        message,
                        show_fix_status: self.show_fix_status,
                        unsafe_fixes: self.unsafe_fixes,
--- a/crates/ruff_linter/src/message/json.rs
+++ b/crates/ruff_linter/src/message/json.rs
@@ -4,12 +4,13 @@ use serde::ser::SerializeSeq;
 use serde::{Serialize, Serializer};
 use serde_json::{Value, json};

+use ruff_db::diagnostic::Diagnostic;
 use ruff_notebook::NotebookIndex;
 use ruff_source_file::{LineColumn, OneIndexed, SourceCode};
 use ruff_text_size::Ranged;

 use crate::Edit;
-use crate::message::{Emitter, EmitterContext, OldDiagnostic};
+use crate::message::{Emitter, EmitterContext};

 #[derive(Default)]
 pub struct JsonEmitter;
@@ -18,7 +19,7 @@ impl Emitter for JsonEmitter {
    fn emit(
        &mut self,
        writer: &mut dyn Write,
-        diagnostics: &[OldDiagnostic],
+        diagnostics: &[Diagnostic],
        context: &EmitterContext,
    ) -> anyhow::Result<()> {
        serde_json::to_writer_pretty(
@@ -34,7 +35,7 @@ impl Emitter for JsonEmitter {
 }

 struct ExpandedMessages<'a> {
-    diagnostics: &'a [OldDiagnostic],
+    diagnostics: &'a [Diagnostic],
    context: &'a EmitterContext<'a>,
 }

@@ -54,10 +55,11 @@ impl Serialize for ExpandedMessages<'_> {
    }
 }

-pub(crate) fn message_to_json_value(message: &OldDiagnostic, context: &EmitterContext) -> Value {
-    let source_file = message.source_file();
+pub(crate) fn message_to_json_value(message: &Diagnostic, context: &EmitterContext) -> Value {
+    let source_file = message.expect_ruff_source_file();
    let source_code = source_file.to_source_code();
-    let notebook_index = context.notebook_index(&message.filename());
+    let filename = message.expect_ruff_filename();
+    let notebook_index = context.notebook_index(&filename);

    let fix = message.fix().map(|fix| {
        json!({
@@ -67,8 +69,8 @@ pub(crate) fn message_to_json_value(message: &OldDiagnostic, context: &EmitterCo
        })
    });

-    let mut start_location = source_code.line_column(message.start());
-    let mut end_location = source_code.line_column(message.end());
+    let mut start_location = source_code.line_column(message.expect_range().start());
+    let mut end_location = source_code.line_column(message.expect_range().end());
    let mut noqa_location = message
        .noqa_offset()
        .map(|offset| source_code.line_column(offset));
@@ -94,7 +96,7 @@ pub(crate) fn message_to_json_value(message: &OldDiagnostic, context: &EmitterCo
        "cell": notebook_cell_index,
        "location": location_to_json(start_location),
        "end_location": location_to_json(end_location),
-        "filename": message.filename(),
+        "filename": filename,
        "noqa_row": noqa_location.map(|location| location.line)
    })
 }
--- a/crates/ruff_linter/src/message/json_lines.rs
+++ b/crates/ruff_linter/src/message/json_lines.rs
@@ -1,7 +1,9 @@
 use std::io::Write;

+use ruff_db::diagnostic::Diagnostic;
+
 use crate::message::json::message_to_json_value;
-use crate::message::{Emitter, EmitterContext, OldDiagnostic};
+use crate::message::{Emitter, EmitterContext};

 #[derive(Default)]
 pub struct JsonLinesEmitter;
@@ -10,7 +12,7 @@ impl Emitter for JsonLinesEmitter {
    fn emit(
        &mut self,
        writer: &mut dyn Write,
-        diagnostics: &[OldDiagnostic],
+        diagnostics: &[Diagnostic],
        context: &EmitterContext,
    ) -> anyhow::Result<()> {
        for diagnostic in diagnostics {
--- a/crates/ruff_linter/src/message/junit.rs
+++ b/crates/ruff_linter/src/message/junit.rs
@@ -3,11 +3,10 @@ use std::path::Path;

 use quick_junit::{NonSuccessKind, Report, TestCase, TestCaseStatus, TestSuite, XmlString};

+use ruff_db::diagnostic::Diagnostic;
 use ruff_source_file::LineColumn;

-use crate::message::{
-    Emitter, EmitterContext, MessageWithLocation, OldDiagnostic, group_diagnostics_by_filename,
-};
+use crate::message::{Emitter, EmitterContext, MessageWithLocation, group_diagnostics_by_filename};

 #[derive(Default)]
 pub struct JunitEmitter;
@@ -16,7 +15,7 @@ impl Emitter for JunitEmitter {
    fn emit(
        &mut self,
        writer: &mut dyn Write,
-        diagnostics: &[OldDiagnostic],
+        diagnostics: &[Diagnostic],
        context: &EmitterContext,
    ) -> anyhow::Result<()> {
        let mut report = Report::new("ruff");
@@ -44,7 +43,7 @@ impl Emitter for JunitEmitter {
                    } = message;
                    let mut status = TestCaseStatus::non_success(NonSuccessKind::Failure);
                    status.set_message(message.body());
-                    let location = if context.is_notebook(&message.filename()) {
+                    let location = if context.is_notebook(&message.expect_ruff_filename()) {
                        // We can't give a reasonable location for the structured formats,
                        // so we show one that's clearly a fallback
                        LineColumn::default()
--- a/crates/ruff_linter/src/message/mod.rs
+++ b/crates/ruff_linter/src/message/mod.rs
@@ -1,11 +1,11 @@
-use std::cmp::Ordering;
 use std::collections::BTreeMap;
 use std::fmt::Display;
 use std::io::Write;
 use std::ops::Deref;

-use ruff_db::diagnostic::{self as db, Annotation, DiagnosticId, LintName, Severity, Span};
-use ruff_python_parser::semantic_errors::SemanticSyntaxError;
+use ruff_db::diagnostic::{
+    Annotation, Diagnostic, DiagnosticId, LintName, SecondaryCode, Severity, Span,
+};
 use rustc_hash::FxHashMap;

 pub use azure::AzureEmitter;
@@ -18,17 +18,13 @@ pub use junit::JunitEmitter;
 pub use pylint::PylintEmitter;
 pub use rdjson::RdjsonEmitter;
 use ruff_notebook::NotebookIndex;
-use ruff_python_parser::{ParseError, UnsupportedSyntaxError};
 use ruff_source_file::{LineColumn, SourceFile};
-use ruff_text_size::{Ranged, TextLen, TextRange, TextSize};
+use ruff_text_size::{Ranged, TextRange, TextSize};
 pub use sarif::SarifEmitter;
 pub use text::TextEmitter;

 use crate::Fix;
-use crate::codes::NoqaCode;
-use crate::logging::DisplayParseErrorType;
 use crate::registry::Rule;
-use crate::{Locator, Violation};

 mod azure;
 mod diff;
@@ -43,292 +39,81 @@ mod rdjson;
 mod sarif;
 mod text;

-/// `OldDiagnostic` represents either a diagnostic message corresponding to a rule violation or a
-/// syntax error message.
+/// Creates a `Diagnostic` from a syntax error, with the format expected by Ruff.
 ///
-/// All of the information for syntax errors is captured in the underlying [`db::Diagnostic`], while
-/// rule violations can have the additional optional fields like fixes, suggestions, and (parent)
-/// `noqa` offsets.
+/// This is almost identical to `ruff_db::diagnostic::create_syntax_error_diagnostic`, except the
+/// `message` is stored as the primary diagnostic message instead of on the primary annotation, and
+/// `SyntaxError: ` is prepended to the message.
 ///
-/// For diagnostic messages, the [`db::Diagnostic`]'s primary message contains the
-/// [`OldDiagnostic::body`], and the primary annotation optionally contains the suggestion
-/// accompanying a fix. The `db::Diagnostic::id` field contains the kebab-case lint name derived
-/// from the `Rule`.
-#[derive(Clone, Debug, PartialEq, Eq)]
-pub struct OldDiagnostic {
-    pub diagnostic: db::Diagnostic,
-
-    // these fields are specific to rule violations
-    pub fix: Option<Fix>,
-    pub parent: Option<TextSize>,
-    pub(crate) noqa_offset: Option<TextSize>,
-    pub(crate) secondary_code: Option<SecondaryCode>,
+/// TODO(brent) These should be unified at some point, but we keep them separate for now to avoid a
+/// ton of snapshot changes while combining ruff's diagnostic type with `Diagnostic`.
+pub fn create_syntax_error_diagnostic(
+    span: impl Into<Span>,
+    message: impl std::fmt::Display,
+    range: impl Ranged,
+) -> Diagnostic {
+    let mut diag = Diagnostic::new(
+        DiagnosticId::InvalidSyntax,
+        Severity::Error,
+        format_args!("SyntaxError: {message}"),
+    );
+    let span = span.into().with_range(range.range());
+    diag.annotate(Annotation::primary(span));
+    diag
 }

-impl OldDiagnostic {
-    pub fn syntax_error(
-        message: impl Display,
-        range: TextRange,
-        file: SourceFile,
-    ) -> OldDiagnostic {
-        let mut diag = db::Diagnostic::new(DiagnosticId::InvalidSyntax, Severity::Error, message);
-        let span = Span::from(file).with_range(range);
-        diag.annotate(Annotation::primary(span));
-        Self {
-            diagnostic: diag,
-            fix: None,
-            parent: None,
-            noqa_offset: None,
-            secondary_code: None,
-        }
+#[expect(clippy::too_many_arguments)]
+pub fn create_lint_diagnostic<B, S>(
+    body: B,
+    suggestion: Option<S>,
+    range: TextRange,
+    fix: Option<Fix>,
+    parent: Option<TextSize>,
+    file: SourceFile,
+    noqa_offset: Option<TextSize>,
+    rule: Rule,
+) -> Diagnostic
+where
+    B: Display,
+    S: Display,
+{
+    let mut diagnostic = Diagnostic::new(
+        DiagnosticId::Lint(LintName::of(rule.into())),
+        Severity::Error,
+        body,
+    );
+
+    if let Some(fix) = fix {
+        diagnostic.set_fix(fix);
    }

-    #[expect(clippy::too_many_arguments)]
-    pub fn lint<B, S>(
-        body: B,
-        suggestion: Option<S>,
-        range: TextRange,
-        fix: Option<Fix>,
-        parent: Option<TextSize>,
-        file: SourceFile,
-        noqa_offset: Option<TextSize>,
-        rule: Rule,
-    ) -> OldDiagnostic
-    where
-        B: Display,
-        S: Display,
-    {
-        let mut diagnostic = db::Diagnostic::new(
-            DiagnosticId::Lint(LintName::of(rule.into())),
-            Severity::Error,
-            body,
-        );
-        let span = Span::from(file).with_range(range);
-        let mut annotation = Annotation::primary(span);
-        if let Some(suggestion) = suggestion {
-            annotation = annotation.message(suggestion);
-        }
-        diagnostic.annotate(annotation);
-
-        OldDiagnostic {
-            diagnostic,
-            fix,
-            parent,
-            noqa_offset,
-            secondary_code: Some(SecondaryCode(rule.noqa_code().to_string())),
-        }
+    if let Some(parent) = parent {
+        diagnostic.set_parent(parent);
    }

-    /// Create an [`OldDiagnostic`] from the given [`ParseError`].
-    pub fn from_parse_error(
-        parse_error: &ParseError,
-        locator: &Locator,
-        file: SourceFile,
-    ) -> OldDiagnostic {
-        // Try to create a non-empty range so that the diagnostic can print a caret at the right
-        // position. This requires that we retrieve the next character, if any, and take its length
-        // to maintain char-boundaries.
-        let len = locator
-            .after(parse_error.location.start())
-            .chars()
-            .next()
-            .map_or(TextSize::new(0), TextLen::text_len);
-
-        OldDiagnostic::syntax_error(
-            format_args!(
-                "SyntaxError: {}",
-                DisplayParseErrorType::new(&parse_error.error)
-            ),
-            TextRange::at(parse_error.location.start(), len),
-            file,
-        )
+    if let Some(noqa_offset) = noqa_offset {
+        diagnostic.set_noqa_offset(noqa_offset);
    }

-    /// Create an [`OldDiagnostic`] from the given [`UnsupportedSyntaxError`].
-    pub fn from_unsupported_syntax_error(
-        unsupported_syntax_error: &UnsupportedSyntaxError,
-        file: SourceFile,
-    ) -> OldDiagnostic {
-        OldDiagnostic::syntax_error(
-            format_args!("SyntaxError: {unsupported_syntax_error}"),
-            unsupported_syntax_error.range,
-            file,
-        )
+    let span = Span::from(file).with_range(range);
+    let mut annotation = Annotation::primary(span);
+    if let Some(suggestion) = suggestion {
+        annotation = annotation.message(suggestion);
    }
+    diagnostic.annotate(annotation);

-    /// Create an [`OldDiagnostic`] from the given [`SemanticSyntaxError`].
-    pub fn from_semantic_syntax_error(
-        semantic_syntax_error: &SemanticSyntaxError,
-        file: SourceFile,
-    ) -> OldDiagnostic {
-        OldDiagnostic::syntax_error(
-            format_args!("SyntaxError: {semantic_syntax_error}"),
-            semantic_syntax_error.range,
-            file,
-        )
-    }
+    diagnostic.set_secondary_code(SecondaryCode::new(rule.noqa_code().to_string()));

-    // TODO(brent) We temporarily allow this to avoid updating all of the call sites to add
-    // references. I expect this method to go away or change significantly with the rest of the
-    // diagnostic refactor, but if it still exists in this form at the end of the refactor, we
-    // should just update the call sites.
-    #[expect(clippy::needless_pass_by_value)]
-    pub fn new<T: Violation>(kind: T, range: TextRange, file: &SourceFile) -> Self {
-        Self::lint(
-            Violation::message(&kind),
-            Violation::fix_title(&kind),
-            range,
-            None,
-            None,
-            file.clone(),
-            None,
-            T::rule(),
-        )
-    }
-
-    /// Consumes `self` and returns a new `Diagnostic` with the given parent node.
-    #[inline]
-    #[must_use]
-    pub fn with_parent(mut self, parent: TextSize) -> Self {
-        self.set_parent(parent);
-        self
-    }
-
-    /// Set the location of the diagnostic's parent node.
-    #[inline]
-    pub fn set_parent(&mut self, parent: TextSize) {
-        self.parent = Some(parent);
-    }
-
-    /// Consumes `self` and returns a new `Diagnostic` with the given noqa offset.
-    #[inline]
-    #[must_use]
-    pub fn with_noqa_offset(mut self, noqa_offset: TextSize) -> Self {
-        self.noqa_offset = Some(noqa_offset);
-        self
-    }
-
-    /// Returns `true` if `self` is a syntax error message.
-    pub fn is_syntax_error(&self) -> bool {
-        self.diagnostic.id().is_invalid_syntax()
-    }
-
-    /// Returns the name used to represent the diagnostic.
-    pub fn name(&self) -> &'static str {
-        if self.is_syntax_error() {
-            "syntax-error"
-        } else {
-            self.diagnostic.id().as_str()
-        }
-    }
-
-    /// Returns the message body to display to the user.
-    pub fn body(&self) -> &str {
-        self.diagnostic.primary_message()
-    }
-
-    /// Returns the fix suggestion for the violation.
-    pub fn suggestion(&self) -> Option<&str> {
-        self.diagnostic.primary_annotation()?.get_message()
-    }
-
-    /// Returns the offset at which the `noqa` comment will be placed if it's a diagnostic message.
-    pub fn noqa_offset(&self) -> Option<TextSize> {
-        self.noqa_offset
-    }
-
-    /// Returns the [`Fix`] for the diagnostic, if there is any.
-    pub fn fix(&self) -> Option<&Fix> {
-        self.fix.as_ref()
-    }
-
-    /// Returns `true` if the diagnostic contains a [`Fix`].
-    pub fn fixable(&self) -> bool {
-        self.fix().is_some()
-    }
-
-    /// Returns the noqa code for the diagnostic message as a string.
-    pub fn secondary_code(&self) -> Option<&SecondaryCode> {
-        self.secondary_code.as_ref()
-    }
-
-    /// Returns the URL for the rule documentation, if it exists.
-    pub fn to_url(&self) -> Option<String> {
-        if self.is_syntax_error() {
-            None
-        } else {
-            Some(format!(
-                "{}/rules/{}",
-                env!("CARGO_PKG_HOMEPAGE"),
-                self.name()
-            ))
-        }
-    }
-
-    /// Returns the filename for the message.
-    pub fn filename(&self) -> String {
-        self.diagnostic
-            .expect_primary_span()
-            .expect_ruff_file()
-            .name()
-            .to_string()
-    }
-
-    /// Computes the start source location for the message.
-    pub fn compute_start_location(&self) -> LineColumn {
-        self.diagnostic
-            .expect_primary_span()
-            .expect_ruff_file()
-            .to_source_code()
-            .line_column(self.start())
-    }
-
-    /// Computes the end source location for the message.
-    pub fn compute_end_location(&self) -> LineColumn {
-        self.diagnostic
-            .expect_primary_span()
-            .expect_ruff_file()
-            .to_source_code()
-            .line_column(self.end())
-    }
-
-    /// Returns the [`SourceFile`] which the message belongs to.
-    pub fn source_file(&self) -> SourceFile {
-        self.diagnostic
-            .expect_primary_span()
-            .expect_ruff_file()
-            .clone()
-    }
-}
-
-impl Ord for OldDiagnostic {
-    fn cmp(&self, other: &Self) -> Ordering {
-        (self.source_file(), self.start()).cmp(&(other.source_file(), other.start()))
-    }
-}
-
-impl PartialOrd for OldDiagnostic {
-    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
-        Some(self.cmp(other))
-    }
-}
-
-impl Ranged for OldDiagnostic {
-    fn range(&self) -> TextRange {
-        self.diagnostic
-            .expect_primary_span()
-            .range()
-            .expect("Expected range for ruff span")
-    }
+    diagnostic
 }

 struct MessageWithLocation<'a> {
-    message: &'a OldDiagnostic,
+    message: &'a Diagnostic,
    start_location: LineColumn,
 }

 impl Deref for MessageWithLocation<'_> {
-    type Target = OldDiagnostic;
+    type Target = Diagnostic;

    fn deref(&self) -> &Self::Target {
        self.message
@@ -336,30 +121,30 @@ impl Deref for MessageWithLocation<'_> {
 }

 fn group_diagnostics_by_filename(
-    diagnostics: &[OldDiagnostic],
+    diagnostics: &[Diagnostic],
 ) -> BTreeMap<String, Vec<MessageWithLocation>> {
    let mut grouped_messages = BTreeMap::default();
    for diagnostic in diagnostics {
        grouped_messages
-            .entry(diagnostic.filename().to_string())
+            .entry(diagnostic.expect_ruff_filename())
            .or_insert_with(Vec::new)
            .push(MessageWithLocation {
                message: diagnostic,
-                start_location: diagnostic.compute_start_location(),
+                start_location: diagnostic.expect_ruff_start_location(),
            });
    }
    grouped_messages
 }

-/// Display format for [`OldDiagnostic`]s.
+/// Display format for [`Diagnostic`]s.
 ///
-/// The emitter serializes a slice of [`OldDiagnostic`]s and writes them to a [`Write`].
+/// The emitter serializes a slice of [`Diagnostic`]s and writes them to a [`Write`].
 pub trait Emitter {
    /// Serializes the `diagnostics` and writes the output to `writer`.
    fn emit(
        &mut self,
        writer: &mut dyn Write,
-        diagnostics: &[OldDiagnostic],
+        diagnostics: &[Diagnostic],
        context: &EmitterContext,
    ) -> anyhow::Result<()>;
 }
@@ -384,101 +169,40 @@ impl<'a> EmitterContext<'a> {
    }
 }

-/// A secondary identifier for a lint diagnostic.
-///
-/// For Ruff rules this means the noqa code.
-#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Default, Hash, serde::Serialize)]
-#[serde(transparent)]
-pub struct SecondaryCode(String);
-
-impl SecondaryCode {
-    pub fn new(code: String) -> Self {
-        Self(code)
-    }
-
-    pub fn as_str(&self) -> &str {
-        &self.0
-    }
-}
-
-impl Display for SecondaryCode {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        f.write_str(&self.0)
-    }
-}
-
-impl std::ops::Deref for SecondaryCode {
-    type Target = str;
-
-    fn deref(&self) -> &Self::Target {
-        &self.0
-    }
-}
-
-impl PartialEq<&str> for SecondaryCode {
-    fn eq(&self, other: &&str) -> bool {
-        self.0 == *other
-    }
-}
-
-impl PartialEq<SecondaryCode> for &str {
-    fn eq(&self, other: &SecondaryCode) -> bool {
-        other.eq(self)
-    }
-}
-
-impl PartialEq<NoqaCode> for SecondaryCode {
-    fn eq(&self, other: &NoqaCode) -> bool {
-        &self.as_str() == other
-    }
-}
-
-impl PartialEq<SecondaryCode> for NoqaCode {
-    fn eq(&self, other: &SecondaryCode) -> bool {
-        other.eq(self)
-    }
-}
-
-// for `hashbrown::EntryRef`
-impl From<&SecondaryCode> for SecondaryCode {
-    fn from(value: &SecondaryCode) -> Self {
-        value.clone()
-    }
-}
-
 #[cfg(test)]
 mod tests {
    use rustc_hash::FxHashMap;

-    use crate::codes::Rule;
-    use crate::{Edit, Fix};
+    use ruff_db::diagnostic::Diagnostic;
    use ruff_notebook::NotebookIndex;
    use ruff_python_parser::{Mode, ParseOptions, parse_unchecked};
    use ruff_source_file::{OneIndexed, SourceFileBuilder};
    use ruff_text_size::{TextRange, TextSize};

-    use crate::Locator;
-    use crate::message::{Emitter, EmitterContext, OldDiagnostic};
+    use crate::codes::Rule;
+    use crate::message::{Emitter, EmitterContext, create_lint_diagnostic};
+    use crate::{Edit, Fix};

-    pub(super) fn create_syntax_error_diagnostics() -> Vec<OldDiagnostic> {
+    use super::create_syntax_error_diagnostic;
+
+    pub(super) fn create_syntax_error_diagnostics() -> Vec<Diagnostic> {
        let source = r"from os import

 if call(foo
    def bar():
        pass
 ";
-        let locator = Locator::new(source);
        let source_file = SourceFileBuilder::new("syntax_errors.py", source).finish();
        parse_unchecked(source, ParseOptions::from(Mode::Module))
            .errors()
            .iter()
            .map(|parse_error| {
-                OldDiagnostic::from_parse_error(parse_error, &locator, source_file.clone())
+                create_syntax_error_diagnostic(source_file.clone(), &parse_error.error, parse_error)
            })
            .collect()
    }

-    pub(super) fn create_diagnostics() -> Vec<OldDiagnostic> {
+    pub(super) fn create_diagnostics() -> Vec<Diagnostic> {
        let fib = r#"import os


@@ -496,7 +220,7 @@ def fibonacci(n):
        let fib_source = SourceFileBuilder::new("fib.py", fib).finish();

        let unused_import_start = TextSize::from(7);
-        let unused_import = OldDiagnostic::lint(
+        let unused_import = create_lint_diagnostic(
            "`os` imported but unused",
            Some("Remove unused import: `os`"),
            TextRange::new(unused_import_start, TextSize::from(9)),
@@ -511,7 +235,7 @@ def fibonacci(n):
        );

        let unused_variable_start = TextSize::from(94);
-        let unused_variable = OldDiagnostic::lint(
+        let unused_variable = create_lint_diagnostic(
            "Local variable `x` is assigned to but never used",
            Some("Remove assignment to unused variable `x`"),
            TextRange::new(unused_variable_start, TextSize::from(95)),
@@ -528,7 +252,7 @@ def fibonacci(n):
        let file_2 = r"if a == 1: pass";

        let undefined_name_start = TextSize::from(3);
-        let undefined_name = OldDiagnostic::lint(
+        let undefined_name = create_lint_diagnostic(
            "Undefined name `a`",
            Option::<&'static str>::None,
            TextRange::new(undefined_name_start, TextSize::from(4)),
@@ -543,7 +267,7 @@ def fibonacci(n):
    }

    pub(super) fn create_notebook_diagnostics()
-    -> (Vec<OldDiagnostic>, FxHashMap<String, NotebookIndex>) {
+    -> (Vec<Diagnostic>, FxHashMap<String, NotebookIndex>) {
        let notebook = r"# cell 1
 import os
 # cell 2
@@ -559,7 +283,7 @@ def foo():
        let notebook_source = SourceFileBuilder::new("notebook.ipynb", notebook).finish();

        let unused_import_os_start = TextSize::from(16);
-        let unused_import_os = OldDiagnostic::lint(
+        let unused_import_os = create_lint_diagnostic(
            "`os` imported but unused",
            Some("Remove unused import: `os`"),
            TextRange::new(unused_import_os_start, TextSize::from(18)),
@@ -574,7 +298,7 @@ def foo():
        );

        let unused_import_math_start = TextSize::from(35);
-        let unused_import_math = OldDiagnostic::lint(
+        let unused_import_math = create_lint_diagnostic(
            "`math` imported but unused",
            Some("Remove unused import: `math`"),
            TextRange::new(unused_import_math_start, TextSize::from(39)),
@@ -589,7 +313,7 @@ def foo():
        );

        let unused_variable_start = TextSize::from(98);
-        let unused_variable = OldDiagnostic::lint(
+        let unused_variable = create_lint_diagnostic(
            "Local variable `x` is assigned to but never used",
            Some("Remove assignment to unused variable `x`"),
            TextRange::new(unused_variable_start, TextSize::from(99)),
@@ -642,7 +366,7 @@ def foo():

    pub(super) fn capture_emitter_output(
        emitter: &mut dyn Emitter,
-        diagnostics: &[OldDiagnostic],
+        diagnostics: &[Diagnostic],
    ) -> String {
        let notebook_indexes = FxHashMap::default();
        let context = EmitterContext::new(&notebook_indexes);
@@ -654,7 +378,7 @@ def foo():

    pub(super) fn capture_emitter_notebook_output(
        emitter: &mut dyn Emitter,
-        diagnostics: &[OldDiagnostic],
+        diagnostics: &[Diagnostic],
        notebook_indexes: &FxHashMap<String, NotebookIndex>,
    ) -> String {
        let context = EmitterContext::new(notebook_indexes);
--- a/crates/ruff_linter/src/message/pylint.rs
+++ b/crates/ruff_linter/src/message/pylint.rs
@@ -1,9 +1,10 @@
 use std::io::Write;

+use ruff_db::diagnostic::Diagnostic;
 use ruff_source_file::OneIndexed;

 use crate::fs::relativize_path;
-use crate::message::{Emitter, EmitterContext, OldDiagnostic};
+use crate::message::{Emitter, EmitterContext};

 /// Generate violations in Pylint format.
 /// See: [Flake8 documentation](https://flake8.pycqa.org/en/latest/internal/formatters.html#pylint-formatter)
@@ -14,16 +15,17 @@ impl Emitter for PylintEmitter {
    fn emit(
        &mut self,
        writer: &mut dyn Write,
-        diagnostics: &[OldDiagnostic],
+        diagnostics: &[Diagnostic],
        context: &EmitterContext,
    ) -> anyhow::Result<()> {
        for diagnostic in diagnostics {
-            let row = if context.is_notebook(&diagnostic.filename()) {
+            let filename = diagnostic.expect_ruff_filename();
+            let row = if context.is_notebook(&filename) {
                // We can't give a reasonable location for the structured formats,
                // so we show one that's clearly a fallback
                OneIndexed::from_zero_indexed(0)
            } else {
-                diagnostic.compute_start_location().line
+                diagnostic.expect_ruff_start_location().line
            };

            let body = if let Some(code) = diagnostic.secondary_code() {
@@ -35,7 +37,7 @@ impl Emitter for PylintEmitter {
            writeln!(
                writer,
                "{path}:{row}: {body}",
-                path = relativize_path(&*diagnostic.filename()),
+                path = relativize_path(&filename),
            )?;
        }

--- a/crates/ruff_linter/src/message/rdjson.rs
+++ b/crates/ruff_linter/src/message/rdjson.rs
@@ -4,11 +4,12 @@ use serde::ser::SerializeSeq;
 use serde::{Serialize, Serializer};
 use serde_json::{Value, json};

+use ruff_db::diagnostic::Diagnostic;
 use ruff_source_file::SourceCode;
 use ruff_text_size::Ranged;

 use crate::Edit;
-use crate::message::{Emitter, EmitterContext, LineColumn, OldDiagnostic};
+use crate::message::{Emitter, EmitterContext, LineColumn};

 #[derive(Default)]
 pub struct RdjsonEmitter;
@@ -17,7 +18,7 @@ impl Emitter for RdjsonEmitter {
    fn emit(
        &mut self,
        writer: &mut dyn Write,
-        diagnostics: &[OldDiagnostic],
+        diagnostics: &[Diagnostic],
        _context: &EmitterContext,
    ) -> anyhow::Result<()> {
        serde_json::to_writer_pretty(
@@ -37,7 +38,7 @@ impl Emitter for RdjsonEmitter {
 }

 struct ExpandedMessages<'a> {
-    diagnostics: &'a [OldDiagnostic],
+    diagnostics: &'a [Diagnostic],
 }

 impl Serialize for ExpandedMessages<'_> {
@@ -56,18 +57,18 @@ impl Serialize for ExpandedMessages<'_> {
    }
 }

-fn message_to_rdjson_value(message: &OldDiagnostic) -> Value {
-    let source_file = message.source_file();
+fn message_to_rdjson_value(message: &Diagnostic) -> Value {
+    let source_file = message.expect_ruff_source_file();
    let source_code = source_file.to_source_code();

-    let start_location = source_code.line_column(message.start());
-    let end_location = source_code.line_column(message.end());
+    let start_location = source_code.line_column(message.expect_range().start());
+    let end_location = source_code.line_column(message.expect_range().end());

    if let Some(fix) = message.fix() {
        json!({
            "message": message.body(),
            "location": {
-                "path": message.filename(),
+                "path": message.expect_ruff_filename(),
                "range": rdjson_range(start_location, end_location),
            },
            "code": {
@@ -80,7 +81,7 @@ fn message_to_rdjson_value(message: &OldDiagnostic) -> Value {
        json!({
            "message": message.body(),
            "location": {
-                "path": message.filename(),
+                "path": message.expect_ruff_filename(),
                "range": rdjson_range(start_location, end_location),
            },
            "code": {
--- a/crates/ruff_linter/src/message/sarif.rs
+++ b/crates/ruff_linter/src/message/sarif.rs
@@ -5,11 +5,12 @@ use anyhow::Result;
 use serde::{Serialize, Serializer};
 use serde_json::json;

+use ruff_db::diagnostic::{Diagnostic, SecondaryCode};
 use ruff_source_file::OneIndexed;

 use crate::VERSION;
 use crate::fs::normalize_path;
-use crate::message::{Emitter, EmitterContext, OldDiagnostic, SecondaryCode};
+use crate::message::{Emitter, EmitterContext};
 use crate::registry::{Linter, RuleNamespace};

 pub struct SarifEmitter;
@@ -18,7 +19,7 @@ impl Emitter for SarifEmitter {
    fn emit(
        &mut self,
        writer: &mut dyn Write,
-        diagnostics: &[OldDiagnostic],
+        diagnostics: &[Diagnostic],
        _context: &EmitterContext,
    ) -> Result<()> {
        let results = diagnostics
@@ -122,10 +123,10 @@ struct SarifResult<'a> {

 impl<'a> SarifResult<'a> {
    #[cfg(not(target_arch = "wasm32"))]
-    fn from_message(message: &'a OldDiagnostic) -> Result<Self> {
-        let start_location = message.compute_start_location();
-        let end_location = message.compute_end_location();
-        let path = normalize_path(&*message.filename());
+    fn from_message(message: &'a Diagnostic) -> Result<Self> {
+        let start_location = message.expect_ruff_start_location();
+        let end_location = message.expect_ruff_end_location();
+        let path = normalize_path(&*message.expect_ruff_filename());
        Ok(Self {
            code: message.secondary_code(),
            level: "error".to_string(),
@@ -142,10 +143,10 @@ impl<'a> SarifResult<'a> {

    #[cfg(target_arch = "wasm32")]
    #[expect(clippy::unnecessary_wraps)]
-    fn from_message(message: &'a OldDiagnostic) -> Result<Self> {
-        let start_location = message.compute_start_location();
-        let end_location = message.compute_end_location();
-        let path = normalize_path(&*message.filename());
+    fn from_message(message: &'a Diagnostic) -> Result<Self> {
+        let start_location = message.expect_ruff_start_location();
+        let end_location = message.expect_ruff_end_location();
+        let path = normalize_path(&*message.expect_ruff_filename());
        Ok(Self {
            code: message.secondary_code(),
            level: "error".to_string(),
--- a/crates/ruff_linter/src/message/text.rs
+++ b/crates/ruff_linter/src/message/text.rs
@@ -6,15 +6,16 @@ use bitflags::bitflags;
 use colored::Colorize;
 use ruff_annotate_snippets::{Level, Renderer, Snippet};

+use ruff_db::diagnostic::{Diagnostic, SecondaryCode};
 use ruff_notebook::NotebookIndex;
 use ruff_source_file::{LineColumn, OneIndexed};
-use ruff_text_size::{Ranged, TextLen, TextRange, TextSize};
+use ruff_text_size::{TextLen, TextRange, TextSize};

 use crate::Locator;
 use crate::fs::relativize_path;
 use crate::line_width::{IndentWidth, LineWidthBuilder};
 use crate::message::diff::Diff;
-use crate::message::{Emitter, EmitterContext, OldDiagnostic, SecondaryCode};
+use crate::message::{Emitter, EmitterContext};
 use crate::settings::types::UnsafeFixes;

 bitflags! {
@@ -66,19 +67,20 @@ impl Emitter for TextEmitter {
    fn emit(
        &mut self,
        writer: &mut dyn Write,
-        diagnostics: &[OldDiagnostic],
+        diagnostics: &[Diagnostic],
        context: &EmitterContext,
    ) -> anyhow::Result<()> {
        for message in diagnostics {
+            let filename = message.expect_ruff_filename();
            write!(
                writer,
                "{path}{sep}",
-                path = relativize_path(&*message.filename()).bold(),
+                path = relativize_path(&filename).bold(),
                sep = ":".cyan(),
            )?;

-            let start_location = message.compute_start_location();
-            let notebook_index = context.notebook_index(&message.filename());
+            let start_location = message.expect_ruff_start_location();
+            let notebook_index = context.notebook_index(&filename);

            // Check if we're working on a jupyter notebook and translate positions with cell accordingly
            let diagnostic_location = if let Some(notebook_index) = notebook_index {
@@ -116,7 +118,7 @@ impl Emitter for TextEmitter {

            if self.flags.intersects(EmitterFlags::SHOW_SOURCE) {
                // The `0..0` range is used to highlight file-level diagnostics.
-                if message.range() != TextRange::default() {
+                if message.expect_range() != TextRange::default() {
                    writeln!(
                        writer,
                        "{}",
@@ -140,7 +142,7 @@ impl Emitter for TextEmitter {
 }

 pub(super) struct RuleCodeAndBody<'a> {
-    pub(crate) message: &'a OldDiagnostic,
+    pub(crate) message: &'a Diagnostic,
    pub(crate) show_fix_status: bool,
    pub(crate) unsafe_fixes: UnsafeFixes,
 }
@@ -178,7 +180,7 @@ impl Display for RuleCodeAndBody<'_> {
 }

 pub(super) struct MessageCodeFrame<'a> {
-    pub(crate) message: &'a OldDiagnostic,
+    pub(crate) message: &'a Diagnostic,
    pub(crate) notebook_index: Option<&'a NotebookIndex>,
 }

@@ -191,10 +193,10 @@ impl Display for MessageCodeFrame<'_> {
            Vec::new()
        };

-        let source_file = self.message.source_file();
+        let source_file = self.message.expect_ruff_source_file();
        let source_code = source_file.to_source_code();

-        let content_start_index = source_code.line_index(self.message.start());
+        let content_start_index = source_code.line_index(self.message.expect_range().start());
        let mut start_index = content_start_index.saturating_sub(2);

        // If we're working with a Jupyter Notebook, skip the lines which are
@@ -217,7 +219,7 @@ impl Display for MessageCodeFrame<'_> {
            start_index = start_index.saturating_add(1);
        }

-        let content_end_index = source_code.line_index(self.message.end());
+        let content_end_index = source_code.line_index(self.message.expect_range().end());
        let mut end_index = content_end_index
            .saturating_add(2)
            .min(OneIndexed::from_zero_indexed(source_code.line_count()));
@@ -248,7 +250,7 @@ impl Display for MessageCodeFrame<'_> {

        let source = replace_whitespace_and_unprintable(
            source_code.slice(TextRange::new(start_offset, end_offset)),
-            self.message.range() - start_offset,
+            self.message.expect_range() - start_offset,
        )
        .fix_up_empty_spans_after_line_terminator();

--- a/crates/ruff_linter/src/noqa.rs
+++ b/crates/ruff_linter/src/noqa.rs
@@ -9,6 +9,7 @@ use anyhow::Result;
 use itertools::Itertools;
 use log::warn;

+use ruff_db::diagnostic::{Diagnostic, SecondaryCode};
 use ruff_python_trivia::{CommentRanges, Cursor, indentation_at_offset};
 use ruff_source_file::{LineEnding, LineRanges};
 use ruff_text_size::{Ranged, TextLen, TextRange, TextSize};
@@ -17,7 +18,6 @@ use rustc_hash::FxHashSet;
 use crate::Edit;
 use crate::Locator;
 use crate::fs::relativize_path;
-use crate::message::{OldDiagnostic, SecondaryCode};
 use crate::registry::Rule;
 use crate::rule_redirects::get_redirect_target;

@@ -28,7 +28,7 @@ use crate::rule_redirects::get_redirect_target;
 /// simultaneously.
 pub fn generate_noqa_edits(
    path: &Path,
-    diagnostics: &[OldDiagnostic],
+    diagnostics: &[Diagnostic],
    locator: &Locator,
    comment_ranges: &CommentRanges,
    external: &[String],
@@ -717,7 +717,7 @@ impl Error for LexicalError {}
 /// Adds noqa comments to suppress all messages of a file.
 pub(crate) fn add_noqa(
    path: &Path,
-    diagnostics: &[OldDiagnostic],
+    diagnostics: &[Diagnostic],
    locator: &Locator,
    comment_ranges: &CommentRanges,
    external: &[String],
@@ -740,7 +740,7 @@ pub(crate) fn add_noqa(

 fn add_noqa_inner(
    path: &Path,
-    diagnostics: &[OldDiagnostic],
+    diagnostics: &[Diagnostic],
    locator: &Locator,
    comment_ranges: &CommentRanges,
    external: &[String],
@@ -845,7 +845,7 @@ struct NoqaComment<'a> {
 }

 fn find_noqa_comments<'a>(
-    diagnostics: &'a [OldDiagnostic],
+    diagnostics: &'a [Diagnostic],
    locator: &'a Locator,
    exemption: &'a FileExemption,
    directives: &'a NoqaDirectives,
@@ -867,7 +867,7 @@ fn find_noqa_comments<'a>(
        }

        // Is the violation ignored by a `noqa` directive on the parent line?
-        if let Some(parent) = message.parent {
+        if let Some(parent) = message.parent() {
            if let Some(directive_line) =
                directives.find_line_with_directive(noqa_line_for.resolve(parent))
            {
@@ -886,7 +886,7 @@ fn find_noqa_comments<'a>(
            }
        }

-        let noqa_offset = noqa_line_for.resolve(message.range().start());
+        let noqa_offset = noqa_line_for.resolve(message.expect_range().start());

        // Or ignored by the directive itself?
        if let Some(directive_line) = directives.find_line_with_directive(noqa_offset) {
@@ -1232,7 +1232,7 @@ mod tests {
    use crate::rules::pycodestyle::rules::{AmbiguousVariableName, UselessSemicolon};
    use crate::rules::pyflakes::rules::UnusedVariable;
    use crate::rules::pyupgrade::rules::PrintfStringFormatting;
-    use crate::{Edit, OldDiagnostic};
+    use crate::{Edit, Violation};
    use crate::{Locator, generate_noqa_edits};

    fn assert_lexed_ranges_match_slices(
@@ -2831,10 +2831,10 @@ mod tests {
        assert_eq!(output, format!("{contents}"));

        let source_file = SourceFileBuilder::new(path.to_string_lossy(), contents).finish();
-        let messages = [OldDiagnostic::new(
-            UnusedVariable {
-                name: "x".to_string(),
-            },
+        let messages = [UnusedVariable {
+            name: "x".to_string(),
+        }
+        .into_diagnostic(
            TextRange::new(TextSize::from(0), TextSize::from(0)),
            &source_file,
        )];
@@ -2855,15 +2855,14 @@ mod tests {

        let source_file = SourceFileBuilder::new(path.to_string_lossy(), contents).finish();
        let messages = [
-            OldDiagnostic::new(
-                AmbiguousVariableName("x".to_string()),
+            AmbiguousVariableName("x".to_string()).into_diagnostic(
                TextRange::new(TextSize::from(0), TextSize::from(0)),
                &source_file,
            ),
-            OldDiagnostic::new(
-                UnusedVariable {
-                    name: "x".to_string(),
-                },
+            UnusedVariable {
+                name: "x".to_string(),
+            }
+            .into_diagnostic(
                TextRange::new(TextSize::from(0), TextSize::from(0)),
                &source_file,
            ),
@@ -2886,15 +2885,14 @@ mod tests {

        let source_file = SourceFileBuilder::new(path.to_string_lossy(), contents).finish();
        let messages = [
-            OldDiagnostic::new(
-                AmbiguousVariableName("x".to_string()),
+            AmbiguousVariableName("x".to_string()).into_diagnostic(
                TextRange::new(TextSize::from(0), TextSize::from(0)),
                &source_file,
            ),
-            OldDiagnostic::new(
-                UnusedVariable {
-                    name: "x".to_string(),
-                },
+            UnusedVariable {
+                name: "x".to_string(),
+            }
+            .into_diagnostic(
                TextRange::new(TextSize::from(0), TextSize::from(0)),
                &source_file,
            ),
@@ -2930,11 +2928,8 @@ print(
 "#;
        let noqa_line_for = [TextRange::new(8.into(), 68.into())].into_iter().collect();
        let source_file = SourceFileBuilder::new(path.to_string_lossy(), source).finish();
-        let messages = [OldDiagnostic::new(
-            PrintfStringFormatting,
-            TextRange::new(12.into(), 79.into()),
-            &source_file,
-        )];
+        let messages = [PrintfStringFormatting
+            .into_diagnostic(TextRange::new(12.into(), 79.into()), &source_file)];
        let comment_ranges = CommentRanges::default();
        let edits = generate_noqa_edits(
            path,
@@ -2963,11 +2958,8 @@ foo;
 bar =
 ";
        let source_file = SourceFileBuilder::new(path.to_string_lossy(), source).finish();
-        let messages = [OldDiagnostic::new(
-            UselessSemicolon,
-            TextRange::new(4.into(), 5.into()),
-            &source_file,
-        )];
+        let messages =
+            [UselessSemicolon.into_diagnostic(TextRange::new(4.into(), 5.into()), &source_file)];
        let noqa_line_for = NoqaMapping::default();
        let comment_ranges = CommentRanges::default();
        let edits = generate_noqa_edits(
--- a/crates/ruff_linter/src/preview.rs
+++ b/crates/ruff_linter/src/preview.rs
@@ -54,6 +54,85 @@ pub(crate) const fn is_fix_manual_list_comprehension_enabled(settings: &LinterSe
 pub(crate) const fn is_fix_os_path_getsize_enabled(settings: &LinterSettings) -> bool {
    settings.preview.is_enabled()
 }
+// https://github.com/astral-sh/ruff/pull/18922
+pub(crate) const fn is_fix_os_path_getmtime_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
+// https://github.com/astral-sh/ruff/pull/18922
+pub(crate) const fn is_fix_os_path_getatime_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
+// https://github.com/astral-sh/ruff/pull/18922
+pub(crate) const fn is_fix_os_path_getctime_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
+// https://github.com/astral-sh/ruff/pull/19213
+pub(crate) const fn is_fix_os_path_abspath_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
+// https://github.com/astral-sh/ruff/pull/19213
+pub(crate) const fn is_fix_os_rmdir_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
+// https://github.com/astral-sh/ruff/pull/19213
+pub(crate) const fn is_fix_os_unlink_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
+// https://github.com/astral-sh/ruff/pull/19213
+pub(crate) const fn is_fix_os_remove_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
+// https://github.com/astral-sh/ruff/pull/19213
+pub(crate) const fn is_fix_os_path_exists_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
+// https://github.com/astral-sh/ruff/pull/19213
+pub(crate) const fn is_fix_os_path_expanduser_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
+// https://github.com/astral-sh/ruff/pull/19213
+pub(crate) const fn is_fix_os_path_isdir_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
+// https://github.com/astral-sh/ruff/pull/19213
+pub(crate) const fn is_fix_os_path_isfile_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
+// https://github.com/astral-sh/ruff/pull/19213
+pub(crate) const fn is_fix_os_path_islink_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
+// https://github.com/astral-sh/ruff/pull/19213
+pub(crate) const fn is_fix_os_path_isabs_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
+// https://github.com/astral-sh/ruff/pull/19213
+pub(crate) const fn is_fix_os_readlink_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
+// https://github.com/astral-sh/ruff/pull/19213
+pub(crate) const fn is_fix_os_path_basename_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
+// https://github.com/astral-sh/ruff/pull/19213
+pub(crate) const fn is_fix_os_path_dirname_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}

 // https://github.com/astral-sh/ruff/pull/11436
 // https://github.com/astral-sh/ruff/pull/11168
@@ -111,3 +190,8 @@ pub(crate) const fn is_safe_super_call_with_parameters_fix_enabled(
 ) -> bool {
    settings.preview.is_enabled()
 }
+
+// https://github.com/astral-sh/ruff/pull/19063
+pub(crate) const fn is_assert_raises_exception_call_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
--- a/crates/ruff_linter/src/pyproject_toml.rs
+++ b/crates/ruff_linter/src/pyproject_toml.rs
@@ -3,19 +3,16 @@ use log::warn;
 use pyproject_toml::PyProjectToml;
 use ruff_text_size::{TextRange, TextSize};

+use ruff_db::diagnostic::Diagnostic;
 use ruff_source_file::SourceFile;

-use crate::IOError;
-use crate::OldDiagnostic;
 use crate::registry::Rule;
 use crate::rules::ruff::rules::InvalidPyprojectToml;
 use crate::settings::LinterSettings;
+use crate::{IOError, Violation};

 /// RUF200
-pub fn lint_pyproject_toml(
-    source_file: &SourceFile,
-    settings: &LinterSettings,
-) -> Vec<OldDiagnostic> {
+pub fn lint_pyproject_toml(source_file: &SourceFile, settings: &LinterSettings) -> Vec<Diagnostic> {
    let Some(err) = toml::from_str::<PyProjectToml>(source_file.source_text()).err() else {
        return Vec::default();
    };
@@ -33,7 +30,7 @@ pub fn lint_pyproject_toml(
                );
                if settings.rules.enabled(Rule::IOError) {
                    let diagnostic =
-                        OldDiagnostic::new(IOError { message }, TextRange::default(), source_file);
+                        IOError { message }.into_diagnostic(TextRange::default(), source_file);
                    messages.push(diagnostic);
                } else {
                    warn!(
@@ -55,11 +52,8 @@ pub fn lint_pyproject_toml(

    if settings.rules.enabled(Rule::InvalidPyprojectToml) {
        let toml_err = err.message().to_string();
-        let diagnostic = OldDiagnostic::new(
-            InvalidPyprojectToml { message: toml_err },
-            range,
-            source_file,
-        );
+        let diagnostic =
+            InvalidPyprojectToml { message: toml_err }.into_diagnostic(range, source_file);
        messages.push(diagnostic);
    }

--- a/crates/ruff_linter/src/rules/flake8_bandit/rules/suspicious_imports.rs
+++ b/crates/ruff_linter/src/rules/flake8_bandit/rules/suspicious_imports.rs
@@ -283,7 +283,7 @@ impl Violation for SuspiciousXmlrpcImport {
 ///
 /// ## Example
 /// ```python
-/// import wsgiref.handlers.CGIHandler
+/// from wsgiref.handlers import CGIHandler
 /// ```
 ///
 /// ## References
--- a/crates/ruff_linter/src/rules/flake8_bandit/snapshots/ruff_linterrulesflake8_bandittestsS112_S112.py.snap
+++ b/crates/ruff_linter/src/rules/flake8_bandit/snapshots/ruff_linterrulesflake8_bandittestsS112_S112.py.snap
@@ -1,46 +1,46 @@
 ---
 source: crates/ruff_linter/src/rules/flake8_bandit/mod.rs
 ---
-S112.py:3:1: S112 `try`-`except`-`continue` detected, consider logging the exception
+S112.py:4:5: S112 `try`-`except`-`continue` detected, consider logging the exception
  |
-1 |   try:
-2 |       pass
-3 | / except Exception:
-4 | |     continue
-  | |____________^ S112
-5 |
-6 |   try:
+2 |       try:
+3 |           pass
+4 | /     except Exception:
+5 | |         continue
+  | |________________^ S112
+6 |
+7 |       try:
  |

-S112.py:8:1: S112 `try`-`except`-`continue` detected, consider logging the exception
+S112.py:9:5: S112 `try`-`except`-`continue` detected, consider logging the exception
   |
- 6 |   try:
- 7 |       pass
- 8 | / except:
- 9 | |     continue
-   | |____________^ S112
-10 |
-11 |   try:
+ 7 |       try:
+ 8 |           pass
+ 9 | /     except:
+10 | |         continue
+   | |________________^ S112
+11 |
+12 |       try:
   |

-S112.py:13:1: S112 `try`-`except`-`continue` detected, consider logging the exception
+S112.py:14:5: S112 `try`-`except`-`continue` detected, consider logging the exception
   |
-11 |   try:
-12 |       pass
-13 | / except (Exception,):
-14 | |     continue
-   | |____________^ S112
-15 |
-16 |   try:
+12 |       try:
+13 |           pass
+14 | /     except (Exception,):
+15 | |         continue
+   | |________________^ S112
+16 |
+17 |       try:
   |

-S112.py:18:1: S112 `try`-`except`-`continue` detected, consider logging the exception
+S112.py:19:5: S112 `try`-`except`-`continue` detected, consider logging the exception
   |
-16 |   try:
-17 |       pass
-18 | / except (Exception, ValueError):
-19 | |     continue
-   | |____________^ S112
-20 |
-21 |   try:
+17 |       try:
+18 |           pass
+19 | /     except (Exception, ValueError):
+20 | |         continue
+   | |________________^ S112
+21 |
+22 |       try:
   |
--- a/crates/ruff_linter/src/rules/flake8_bugbear/mod.rs
+++ b/crates/ruff_linter/src/rules/flake8_bugbear/mod.rs
@@ -16,11 +16,14 @@ mod tests {
    use crate::settings::LinterSettings;
    use crate::test::test_path;

+    use crate::settings::types::PreviewMode;
+
    use ruff_python_ast::PythonVersion;

    #[test_case(Rule::AbstractBaseClassWithoutAbstractMethod, Path::new("B024.py"))]
    #[test_case(Rule::AssertFalse, Path::new("B011.py"))]
-    #[test_case(Rule::AssertRaisesException, Path::new("B017.py"))]
+    #[test_case(Rule::AssertRaisesException, Path::new("B017_0.py"))]
+    #[test_case(Rule::AssertRaisesException, Path::new("B017_1.py"))]
    #[test_case(Rule::AssignmentToOsEnviron, Path::new("B003.py"))]
    #[test_case(Rule::CachedInstanceMethod, Path::new("B019.py"))]
    #[test_case(Rule::ClassAsDataStructure, Path::new("class_as_data_structure.py"))]
@@ -174,4 +177,23 @@ mod tests {
        assert_diagnostics!(snapshot, diagnostics);
        Ok(())
    }
+
+    #[test_case(Rule::AssertRaisesException, Path::new("B017_0.py"))]
+    #[test_case(Rule::AssertRaisesException, Path::new("B017_1.py"))]
+    fn rules_preview(rule_code: Rule, path: &Path) -> Result<()> {
+        let snapshot = format!(
+            "preview__{}_{}",
+            rule_code.noqa_code(),
+            path.to_string_lossy()
+        );
+        let diagnostics = test_path(
+            Path::new("flake8_bugbear").join(path).as_path(),
+            &LinterSettings {
+                preview: PreviewMode::Enabled,
+                ..LinterSettings::for_rule(rule_code)
+            },
+        )?;
+        assert_diagnostics!(snapshot, diagnostics);
+        Ok(())
+    }
 }
--- a/crates/ruff_linter/src/rules/flake8_bugbear/rules/assert_raises_exception.rs
+++ b/crates/ruff_linter/src/rules/flake8_bugbear/rules/assert_raises_exception.rs
@@ -1,7 +1,7 @@
 use std::fmt;

 use ruff_macros::{ViolationMetadata, derive_message_formats};
-use ruff_python_ast::{self as ast, Expr, WithItem};
+use ruff_python_ast::{self as ast, Arguments, Expr, WithItem};
 use ruff_text_size::Ranged;

 use crate::Violation;
@@ -56,6 +56,48 @@ impl fmt::Display for ExceptionKind {
    }
 }

+fn detect_blind_exception(
+    semantic: &ruff_python_semantic::SemanticModel<'_>,
+    func: &Expr,
+    arguments: &Arguments,
+) -> Option<ExceptionKind> {
+    let is_assert_raises = matches!(
+        func,
+        &Expr::Attribute(ast::ExprAttribute { ref attr, .. }) if attr.as_str() == "assertRaises"
+    );
+
+    let is_pytest_raises = semantic
+        .resolve_qualified_name(func)
+        .is_some_and(|qualified_name| matches!(qualified_name.segments(), ["pytest", "raises"]));
+
+    if !(is_assert_raises || is_pytest_raises) {
+        return None;
+    }
+
+    if is_pytest_raises {
+        if arguments.find_keyword("match").is_some() {
+            return None;
+        }
+
+        if arguments
+            .find_positional(1)
+            .is_some_and(|arg| matches!(arg, Expr::StringLiteral(_) | Expr::BytesLiteral(_)))
+        {
+            return None;
+        }
+    }
+
+    let first_arg = arguments.args.first()?;
+
+    let builtin_symbol = semantic.resolve_builtin_symbol(first_arg)?;
+
+    match builtin_symbol {
+        "Exception" => Some(ExceptionKind::Exception),
+        "BaseException" => Some(ExceptionKind::BaseException),
+        _ => None,
+    }
+}
+
 /// B017
 pub(crate) fn assert_raises_exception(checker: &Checker, items: &[WithItem]) {
    for item in items {
@@ -73,33 +115,31 @@ pub(crate) fn assert_raises_exception(checker: &Checker, items: &[WithItem]) {
            continue;
        }

-        let [arg] = &*arguments.args else {
-            continue;
-        };
-
-        let semantic = checker.semantic();
-
-        let Some(builtin_symbol) = semantic.resolve_builtin_symbol(arg) else {
-            continue;
-        };
-
-        let exception = match builtin_symbol {
-            "Exception" => ExceptionKind::Exception,
-            "BaseException" => ExceptionKind::BaseException,
-            _ => continue,
-        };
-
-        if !(matches!(func.as_ref(), Expr::Attribute(ast::ExprAttribute { attr, .. }) if attr == "assertRaises")
-            || semantic
-                .resolve_qualified_name(func)
-                .is_some_and(|qualified_name| {
-                    matches!(qualified_name.segments(), ["pytest", "raises"])
-                })
-                && arguments.find_keyword("match").is_none())
+        if let Some(exception) =
+            detect_blind_exception(checker.semantic(), func.as_ref(), arguments)
        {
-            continue;
+            checker.report_diagnostic(AssertRaisesException { exception }, item.range());
        }
-
-        checker.report_diagnostic(AssertRaisesException { exception }, item.range());
+    }
+}
+
+/// B017 (call form)
+pub(crate) fn assert_raises_exception_call(
+    checker: &Checker,
+    ast::ExprCall {
+        func,
+        arguments,
+        range,
+        node_index: _,
+    }: &ast::ExprCall,
+) {
+    let semantic = checker.semantic();
+
+    if arguments.args.len() < 2 && arguments.find_argument("func", 1).is_none() {
+        return;
+    }
+
+    if let Some(exception) = detect_blind_exception(semantic, func.as_ref(), arguments) {
+        checker.report_diagnostic(AssertRaisesException { exception }, *range);
    }
 }
--- a/crates/ruff_linter/src/rules/flake8_bugbear/snapshots/ruff_linterrulesflake8_bugbeartestsB017_B017_0.py.snap
+++ b/crates/ruff_linter/src/rules/flake8_bugbear/snapshots/ruff_linterrulesflake8_bugbeartestsB017_B017_0.py.snap
@@ -1,7 +1,7 @@
 ---
 source: crates/ruff_linter/src/rules/flake8_bugbear/mod.rs
 ---
-B017.py:23:14: B017 Do not assert blind exception: `Exception`
+B017_0.py:23:14: B017 Do not assert blind exception: `Exception`
   |
 21 | class Foobar(unittest.TestCase):
 22 |     def evil_raises(self) -> None:
@@ -10,7 +10,7 @@ B017.py:23:14: B017 Do not assert blind exception: `Exception`
 24 |             raise Exception("Evil I say!")
   |

-B017.py:27:14: B017 Do not assert blind exception: `BaseException`
+B017_0.py:27:14: B017 Do not assert blind exception: `BaseException`
   |
 26 |     def also_evil_raises(self) -> None:
 27 |         with self.assertRaises(BaseException):
@@ -18,7 +18,7 @@ B017.py:27:14: B017 Do not assert blind exception: `BaseException`
 28 |             raise Exception("Evil I say!")
   |

-B017.py:45:10: B017 Do not assert blind exception: `Exception`
+B017_0.py:45:10: B017 Do not assert blind exception: `Exception`
   |
 44 | def test_pytest_raises():
 45 |     with pytest.raises(Exception):
@@ -26,7 +26,7 @@ B017.py:45:10: B017 Do not assert blind exception: `Exception`
 46 |         raise ValueError("Hello")
   |

-B017.py:48:10: B017 Do not assert blind exception: `Exception`
+B017_0.py:48:10: B017 Do not assert blind exception: `Exception`
   |
 46 |         raise ValueError("Hello")
 47 |
@@ -35,7 +35,7 @@ B017.py:48:10: B017 Do not assert blind exception: `Exception`
 49 |         raise ValueError("Hello")
   |

-B017.py:57:36: B017 Do not assert blind exception: `Exception`
+B017_0.py:57:36: B017 Do not assert blind exception: `Exception`
   |
 55 |         raise ValueError("This is also fine")
 56 |
--- a/crates/ruff_linter/src/rules/flake8_bugbear/snapshots/ruff_linterrulesflake8_bugbeartestsB017_B017_1.py.snap
+++ b/crates/ruff_linter/src/rules/flake8_bugbear/snapshots/ruff_linterrulesflake8_bugbeartestsB017_B017_1.py.snap
@@ -0,0 +1,4 @@
+---
+source: crates/ruff_linter/src/rules/flake8_bugbear/mod.rs
+---
+
--- a/crates/ruff_linter/src/rules/flake8_bugbear/snapshots/ruff_linterrulesflake8_bugbeartestsB031_B031.py.snap
+++ b/crates/ruff_linter/src/rules/flake8_bugbear/snapshots/ruff_linterrulesflake8_bugbeartestsB031_B031.py.snap
@@ -195,31 +195,31 @@ B031.py:144:33: B031 Using the generator returned from `itertools.groupby()` mor
 146 | for group in groupby(items, key=lambda p: p[1]):
    |

-B031.py:200:37: B031 Using the generator returned from `itertools.groupby()` more than once will do nothing on the second usage
+B031.py:203:41: B031 Using the generator returned from `itertools.groupby()` more than once will do nothing on the second usage
    |
-198 |     if _section == "greens":
-199 |         collect_shop_items(shopper, section_items)
-200 |         collect_shop_items(shopper, section_items)
-    |                                     ^^^^^^^^^^^^^ B031
-201 |         return
+201 |         if _section == "greens":
+202 |             collect_shop_items(shopper, section_items)
+203 |             collect_shop_items(shopper, section_items)
+    |                                         ^^^^^^^^^^^^^ B031
+204 |             return
    |

-B031.py:210:37: B031 Using the generator returned from `itertools.groupby()` more than once will do nothing on the second usage
+B031.py:215:41: B031 Using the generator returned from `itertools.groupby()` more than once will do nothing on the second usage
    |
-208 |     elif _section == "frozen items":
-209 |         collect_shop_items(shopper, section_items)
-210 |         collect_shop_items(shopper, section_items)
-    |                                     ^^^^^^^^^^^^^ B031
-211 |
-212 | # Should trigger, since only one branch has a return statement.
+213 |         elif _section == "frozen items":
+214 |             collect_shop_items(shopper, section_items)
+215 |             collect_shop_items(shopper, section_items)
+    |                                         ^^^^^^^^^^^^^ B031
+216 |
+217 | # Should trigger, since only one branch has a return statement.
    |

-B031.py:219:33: B031 Using the generator returned from `itertools.groupby()` more than once will do nothing on the second usage
+B031.py:226:37: B031 Using the generator returned from `itertools.groupby()` more than once will do nothing on the second usage
    |
-217 |     elif _section == "frozen items":
-218 |         collect_shop_items(shopper, section_items)
-219 |     collect_shop_items(shopper, section_items)  # B031
-    |                                 ^^^^^^^^^^^^^ B031
-220 |
-221 | # Let's redefine the `groupby` function to make sure we pick up the correct one.
+224 |         elif _section == "frozen items":
+225 |             collect_shop_items(shopper, section_items)
+226 |         collect_shop_items(shopper, section_items)  # B031
+    |                                     ^^^^^^^^^^^^^ B031
+227 |
+228 | # Let's redefine the `groupby` function to make sure we pick up the correct one.
    |
--- a/crates/ruff_linter/src/rules/flake8_bugbear/snapshots/ruff_linterrulesflake8_bugbeartestspreview__B017_B017_0.py.snap
+++ b/crates/ruff_linter/src/rules/flake8_bugbear/snapshots/ruff_linterrulesflake8_bugbeartestspreview__B017_B017_0.py.snap
@@ -0,0 +1,45 @@
+---
+source: crates/ruff_linter/src/rules/flake8_bugbear/mod.rs
+---
+B017_0.py:23:14: B017 Do not assert blind exception: `Exception`
+   |
+21 | class Foobar(unittest.TestCase):
+22 |     def evil_raises(self) -> None:
+23 |         with self.assertRaises(Exception):
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ B017
+24 |             raise Exception("Evil I say!")
+   |
+
+B017_0.py:27:14: B017 Do not assert blind exception: `BaseException`
+   |
+26 |     def also_evil_raises(self) -> None:
+27 |         with self.assertRaises(BaseException):
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ B017
+28 |             raise Exception("Evil I say!")
+   |
+
+B017_0.py:45:10: B017 Do not assert blind exception: `Exception`
+   |
+44 | def test_pytest_raises():
+45 |     with pytest.raises(Exception):
+   |          ^^^^^^^^^^^^^^^^^^^^^^^^ B017
+46 |         raise ValueError("Hello")
+   |
+
+B017_0.py:48:10: B017 Do not assert blind exception: `Exception`
+   |
+46 |         raise ValueError("Hello")
+47 |
+48 |     with pytest.raises(Exception), pytest.raises(ValueError):
+   |          ^^^^^^^^^^^^^^^^^^^^^^^^ B017
+49 |         raise ValueError("Hello")
+   |
+
+B017_0.py:57:36: B017 Do not assert blind exception: `Exception`
+   |
+55 |         raise ValueError("This is also fine")
+56 |
+57 |     with contextlib.nullcontext(), pytest.raises(Exception):
+   |                                    ^^^^^^^^^^^^^^^^^^^^^^^^ B017
+58 |         raise ValueError("Multiple context managers")
+   |
--- a/crates/ruff_linter/src/rules/flake8_bugbear/snapshots/ruff_linterrulesflake8_bugbeartestspreview__B017_B017_1.py.snap
+++ b/crates/ruff_linter/src/rules/flake8_bugbear/snapshots/ruff_linterrulesflake8_bugbeartestspreview__B017_B017_1.py.snap
@@ -0,0 +1,37 @@
+---
+source: crates/ruff_linter/src/rules/flake8_bugbear/mod.rs
+---
+B017_1.py:20:9: B017 Do not assert blind exception: `Exception`
+   |
+18 | class Foobar(unittest.TestCase):
+19 |     def call_form_raises(self) -> None:
+20 |         self.assertRaises(Exception, something_else)
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ B017
+21 |         self.assertRaises(BaseException, something_else)
+   |
+
+B017_1.py:21:9: B017 Do not assert blind exception: `BaseException`
+   |
+19 |     def call_form_raises(self) -> None:
+20 |         self.assertRaises(Exception, something_else)
+21 |         self.assertRaises(BaseException, something_else)
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ B017
+   |
+
+B017_1.py:25:5: B017 Do not assert blind exception: `Exception`
+   |
+24 | def test_pytest_call_form() -> None:
+25 |     pytest.raises(Exception, something_else)
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ B017
+26 |     pytest.raises(BaseException, something_else)
+   |
+
+B017_1.py:26:5: B017 Do not assert blind exception: `BaseException`
+   |
+24 | def test_pytest_call_form() -> None:
+25 |     pytest.raises(Exception, something_else)
+26 |     pytest.raises(BaseException, something_else)
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ B017
+27 |
+28 |     pytest.raises(Exception, something_else, match="hello")
+   |
--- a/crates/ruff_linter/src/rules/flake8_commas/rules/trailing_commas.rs
+++ b/crates/ruff_linter/src/rules/flake8_commas/rules/trailing_commas.rs
@@ -355,7 +355,7 @@ fn check_token(
        if let Some(mut diagnostic) =
            lint_context.report_diagnostic_if_enabled(ProhibitedTrailingComma, prev.range())
        {
-            let range = diagnostic.range();
+            let range = diagnostic.expect_range();
            diagnostic.set_fix(Fix::safe_edit(Edit::range_deletion(range)));
            return;
        }
--- a/crates/ruff_linter/src/rules/flake8_commas/snapshots/ruff_linterrulesflake8_commastestsCOM81_syntax_error.py.snap
+++ b/crates/ruff_linter/src/rules/flake8_commas/snapshots/ruff_linterrulesflake8_commastestsCOM81_syntax_error.py.snap
@@ -6,7 +6,7 @@ COM81_syntax_error.py:3:5: SyntaxError: Starred expression cannot be used here
 1 | # Check for `flake8-commas` violation for a file containing syntax errors.
 2 | (
 3 |     *args
-  |     ^
+  |     ^^^^^
 4 | )
  |

--- a/Show More
+++ b/Show More