Bump 0.12.5 (#19528)

This PR adds support for "go to references" in the ty playground.

<img width="393" height="168" alt="image"
src="https://github.com/user-attachments/assets/ce3ae1bf-c17c-4510-9f77-20b10f6170c4"
/>

---------

Co-authored-by: UnboundVariable <unbound@gmail.com>

.github/workflows/ci.yaml

@@ -143,12 +143,12 @@ jobs:
         env:
           MERGE_BASE: ${{ steps.merge_base.outputs.sha }}
         run: |
-          if git diff --quiet "${MERGE_BASE}...HEAD" -- ':**' \
-            ':!**/*.md' \
-            ':crates/ty_python_semantic/resources/mdtest/**/*.md' \
+          # NOTE: Do not exclude all Markdown files here, but rather use
+          # specific exclude patterns like 'docs/**'), because tests for
+          # 'ty' are written in Markdown.
+          if git diff --quiet "${MERGE_BASE}...HEAD" -- \
             ':!docs/**' \
             ':!assets/**' \
-            ':.github/workflows/ci.yaml' \
           ; then
               echo "changed=false" >> "$GITHUB_OUTPUT"
           else
@@ -238,13 +238,13 @@ jobs:
       - name: "Install Rust toolchain"
         run: rustup show
       - name: "Install mold"
-        uses: rui314/setup-mold@85c79d00377f0d32cdbae595a46de6f7c2fa6599 # v1
+        uses: rui314/setup-mold@702b1908b5edf30d71a8d1666b724e0f0c6fa035 # v1
       - name: "Install cargo nextest"
-        uses: taiki-e/install-action@c07504cae06f832dc8de08911c9a9c5cddb0d2d3 # v2.56.13
+        uses: taiki-e/install-action@c99cc51b309eee71a866715cfa08c922f11cf898 # v2.56.19
         with:
           tool: cargo-nextest
       - name: "Install cargo insta"
-        uses: taiki-e/install-action@c07504cae06f832dc8de08911c9a9c5cddb0d2d3 # v2.56.13
+        uses: taiki-e/install-action@c99cc51b309eee71a866715cfa08c922f11cf898 # v2.56.19
         with:
           tool: cargo-insta
       - name: ty mdtests (GitHub annotations)
@@ -296,13 +296,13 @@ jobs:
       - name: "Install Rust toolchain"
         run: rustup show
       - name: "Install mold"
-        uses: rui314/setup-mold@85c79d00377f0d32cdbae595a46de6f7c2fa6599 # v1
+        uses: rui314/setup-mold@702b1908b5edf30d71a8d1666b724e0f0c6fa035 # v1
       - name: "Install cargo nextest"
-        uses: taiki-e/install-action@c07504cae06f832dc8de08911c9a9c5cddb0d2d3 # v2.56.13
+        uses: taiki-e/install-action@c99cc51b309eee71a866715cfa08c922f11cf898 # v2.56.19
         with:
           tool: cargo-nextest
       - name: "Install cargo insta"
-        uses: taiki-e/install-action@c07504cae06f832dc8de08911c9a9c5cddb0d2d3 # v2.56.13
+        uses: taiki-e/install-action@c99cc51b309eee71a866715cfa08c922f11cf898 # v2.56.19
         with:
           tool: cargo-insta
       - name: "Run tests"
@@ -325,7 +325,7 @@ jobs:
       - name: "Install Rust toolchain"
         run: rustup show
       - name: "Install cargo nextest"
-        uses: taiki-e/install-action@c07504cae06f832dc8de08911c9a9c5cddb0d2d3 # v2.56.13
+        uses: taiki-e/install-action@c99cc51b309eee71a866715cfa08c922f11cf898 # v2.56.19
         with:
           tool: cargo-nextest
       - name: "Run tests"
@@ -381,7 +381,7 @@ jobs:
       - name: "Install Rust toolchain"
         run: rustup show
       - name: "Install mold"
-        uses: rui314/setup-mold@85c79d00377f0d32cdbae595a46de6f7c2fa6599 # v1
+        uses: rui314/setup-mold@702b1908b5edf30d71a8d1666b724e0f0c6fa035 # v1
       - name: "Build"
         run: cargo build --release --locked
 
@@ -406,7 +406,7 @@ jobs:
           MSRV: ${{ steps.msrv.outputs.value }}
         run: rustup default "${MSRV}"
       - name: "Install mold"
-        uses: rui314/setup-mold@85c79d00377f0d32cdbae595a46de6f7c2fa6599 # v1
+        uses: rui314/setup-mold@702b1908b5edf30d71a8d1666b724e0f0c6fa035 # v1
       - name: "Build tests"
         shell: bash
         env:
@@ -903,7 +903,7 @@ jobs:
         run: rustup show
 
       - name: "Install codspeed"
-        uses: taiki-e/install-action@c07504cae06f832dc8de08911c9a9c5cddb0d2d3 # v2.56.13
+        uses: taiki-e/install-action@c99cc51b309eee71a866715cfa08c922f11cf898 # v2.56.19
         with:
           tool: cargo-codspeed
 
@@ -936,7 +936,7 @@ jobs:
         run: rustup show
 
       - name: "Install codspeed"
-        uses: taiki-e/install-action@c07504cae06f832dc8de08911c9a9c5cddb0d2d3 # v2.56.13
+        uses: taiki-e/install-action@c99cc51b309eee71a866715cfa08c922f11cf898 # v2.56.19
         with:
           tool: cargo-codspeed
 

.github/workflows/daily_fuzz.yaml

@@ -38,7 +38,7 @@ jobs:
       - name: "Install Rust toolchain"
         run: rustup show
       - name: "Install mold"
-        uses: rui314/setup-mold@85c79d00377f0d32cdbae595a46de6f7c2fa6599 # v1
+        uses: rui314/setup-mold@702b1908b5edf30d71a8d1666b724e0f0c6fa035 # v1
       - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
       - name: Build ruff
         # A debug build means the script runs slower once it gets started,

.github/workflows/sync_typeshed.yaml

@@ -34,6 +34,10 @@ env:
   # and which all three workers push to.
   UPSTREAM_BRANCH: typeshedbot/sync-typeshed
 
+  # The path to the directory that contains the vendored typeshed stubs,
+  # relative to the root of the Ruff repository.
+  VENDORED_TYPESHED: crates/ty_vendored/vendor/typeshed
+
 jobs:
   # Sync typeshed stubs, and sync all docstrings available on Linux.
   # Push the changes to a new branch on the upstream repository.
@@ -64,20 +68,20 @@ jobs:
       - uses: astral-sh/setup-uv@bd01e18f51369d5a26f1651c3cb451d3417e3bba # v6.3.1
       - name: Sync typeshed stubs
         run: |
-          rm -rf ruff/crates/ty_vendored/vendor/typeshed
-          mkdir ruff/crates/ty_vendored/vendor/typeshed
-          cp typeshed/README.md ruff/crates/ty_vendored/vendor/typeshed
-          cp typeshed/LICENSE ruff/crates/ty_vendored/vendor/typeshed
+          rm -rf "ruff/${VENDORED_TYPESHED}"
+          mkdir "ruff/${VENDORED_TYPESHED}"
+          cp typeshed/README.md "ruff/${VENDORED_TYPESHED}"
+          cp typeshed/LICENSE "ruff/${VENDORED_TYPESHED}"
 
           # The pyproject.toml file is needed by a later job for the black configuration.
           # It's deleted before creating the PR.
-          cp typeshed/pyproject.toml ruff/crates/ty_vendored/vendor/typeshed
+          cp typeshed/pyproject.toml "ruff/${VENDORED_TYPESHED}"
 
-          cp -r typeshed/stdlib ruff/crates/ty_vendored/vendor/typeshed/stdlib
-          rm -rf ruff/crates/ty_vendored/vendor/typeshed/stdlib/@tests
-          git -C typeshed rev-parse HEAD > ruff/crates/ty_vendored/vendor/typeshed/source_commit.txt
+          cp -r typeshed/stdlib "ruff/${VENDORED_TYPESHED}/stdlib"
+          rm -rf "ruff/${VENDORED_TYPESHED}/stdlib/@tests"
+          git -C typeshed rev-parse HEAD > "ruff/${VENDORED_TYPESHED}/source_commit.txt"
           cd ruff
-          git checkout -b typeshedbot/sync-typeshed
+          git checkout -b "${UPSTREAM_BRANCH}"
           git add .
           git commit -m "Sync typeshed. Source commit: https://github.com/python/typeshed/commit/$(git -C ../typeshed rev-parse HEAD)" --allow-empty
       - name: Sync Linux docstrings
@@ -167,17 +171,17 @@ jobs:
           # consistent with the other typeshed stubs around them.
           # Typeshed formats code using black in their CI, so we just invoke
           # black on the stubs the same way that typeshed does.
-          uvx black crates/ty_vendored/vendor/typeshed/stdlib --config crates/ty_vendored/vendor/typeshed/pyproject.toml || true
+          uvx black "${VENDORED_TYPESHED}/stdlib" --config "${VENDORED_TYPESHED}/pyproject.toml" || true
           git commit -am "Format codemodded docstrings" --allow-empty
 
-          rm crates/ty_vendored/vendor/typeshed/pyproject.toml
+          rm "${VENDORED_TYPESHED}/pyproject.toml"
           git commit -am "Remove pyproject.toml file"
 
           git push
       - name: Create a PR
         if: ${{ success() }}
         run: |
-          gh pr list --repo "$GITHUB_REPOSITORY" --head typeshedbot/sync-typeshed --json id --jq length | grep 1 && exit 0 # exit if there is existing pr
+          gh pr list --repo "${GITHUB_REPOSITORY}" --head "${UPSTREAM_BRANCH}" --json id --jq length | grep 1 && exit 0 # exit if there is existing pr
           gh pr create --title "[ty] Sync vendored typeshed stubs" --body "Close and reopen this PR to trigger CI" --label "ty"
 
   create-issue-on-failure:

.github/workflows/ty-ecosystem-analyzer.yaml

@@ -64,7 +64,7 @@ jobs:
 
           cd ..
 
-          uv tool install "git+https://github.com/astral-sh/ecosystem-analyzer@f0eec0e549684d8e1d7b8bc3e351202124b63bda"
+          uv tool install "git+https://github.com/astral-sh/ecosystem-analyzer@27dd66d9e397d986ef9c631119ee09556eab8af9"
 
           ecosystem-analyzer \
             --repository ruff \

.github/workflows/ty-ecosystem-report.yaml

@@ -49,7 +49,7 @@ jobs:
 
           cd ..
 
-          uv tool install "git+https://github.com/astral-sh/ecosystem-analyzer@f0eec0e549684d8e1d7b8bc3e351202124b63bda"
+          uv tool install "git+https://github.com/astral-sh/ecosystem-analyzer@27dd66d9e397d986ef9c631119ee09556eab8af9"
 
           ecosystem-analyzer \
             --verbose \

.pre-commit-config.yaml

@@ -81,7 +81,7 @@ repos:
         pass_filenames: false # This makes it a lot faster
 
   - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.12.3
+    rev: v0.12.4
     hooks:
       - id: ruff-format
       - id: ruff

CHANGELOG.md

@@ -1,5 +1,23 @@
 # Changelog
 
+## 0.12.5
+
+### Preview features
+
+- \[`flake8-use-pathlib`\] Add autofix for `PTH101`, `PTH104`, `PTH105`, `PTH121` ([#19404](https://github.com/astral-sh/ruff/pull/19404))
+- \[`ruff`\] Support byte strings (`RUF055`) ([#18926](https://github.com/astral-sh/ruff/pull/18926))
+
+### Bug fixes
+
+- Fix `unreachable` panic in parser ([#19183](https://github.com/astral-sh/ruff/pull/19183))
+- \[`flake8-pyi`\] Skip fix if all `Union` members are `None` (`PYI016`) ([#19416](https://github.com/astral-sh/ruff/pull/19416))
+- \[`perflint`\] Parenthesize generator expressions (`PERF401`) ([#19325](https://github.com/astral-sh/ruff/pull/19325))
+- \[`pylint`\] Handle empty comments after line continuation (`PLR2044`) ([#19405](https://github.com/astral-sh/ruff/pull/19405))
+
+### Rule changes
+
+- \[`pep8-naming`\] Fix `N802` false positives for `CGIHTTPRequestHandler` and `SimpleHTTPRequestHandler` ([#19432](https://github.com/astral-sh/ruff/pull/19432))
+
 ## 0.12.4
 
 ### Preview features

Cargo.lock

@@ -261,6 +261,18 @@ version = "2.9.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1b8e56985ec62d17e9c1001dc89c88ecd7dc08e47eba5ec7c29c7b5eeecde967"
 
+[[package]]
+name = "bitvec"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1bc2832c24239b0141d5674bb9174f9d68a8b5b3f2753311927c172ca46f7e9c"
+dependencies = [
+ "funty",
+ "radium",
+ "tap",
+ "wyz",
+]
+
 [[package]]
 name = "block-buffer"
 version = "0.10.4"
@@ -1121,6 +1133,12 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "funty"
+version = "2.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e6d5a32815ae3f33302d95fdcb2ce17862f8c65363dcfd29360480ba1001fc9c"
+
 [[package]]
 name = "generic-array"
 version = "0.14.7"
@@ -2548,6 +2566,12 @@ version = "5.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "74765f6d916ee2faa39bc8e68e4f3ed8949b48cccdac59983d287a7cb71ce9c5"
 
+[[package]]
+name = "radium"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dc33ff2d4973d518d823d61aa239014831e521c75da58e3df4840d3f47749d09"
+
 [[package]]
 name = "rand"
 version = "0.8.5"
@@ -2561,9 +2585,9 @@ dependencies = [
 
 [[package]]
 name = "rand"
-version = "0.9.1"
+version = "0.9.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9fbfd9d094a40bf3ae768db9361049ace4c0e04a4fd6b359518bd7b73a73dd97"
+checksum = "6db2770f06117d490610c7488547d543617b21bfa07796d7a12f6f1bd53850d1"
 dependencies = [
  "rand_chacha 0.9.0",
  "rand_core 0.9.3",
@@ -2710,7 +2734,7 @@ dependencies = [
 
 [[package]]
 name = "ruff"
-version = "0.12.4"
+version = "0.12.5"
 dependencies = [
  "anyhow",
  "argfile",
@@ -2827,7 +2851,6 @@ dependencies = [
  "anstyle",
  "arc-swap",
  "camino",
- "countme",
  "dashmap",
  "dunce",
  "etcetera",
@@ -2962,7 +2985,7 @@ dependencies = [
 
 [[package]]
 name = "ruff_linter"
-version = "0.12.4"
+version = "0.12.5"
 dependencies = [
  "aho-corasick",
  "anyhow",
@@ -3041,7 +3064,7 @@ version = "0.0.0"
 dependencies = [
  "anyhow",
  "itertools 0.14.0",
- "rand 0.9.1",
+ "rand 0.9.2",
  "ruff_diagnostics",
  "ruff_source_file",
  "ruff_text_size",
@@ -3294,7 +3317,7 @@ dependencies = [
 
 [[package]]
 name = "ruff_wasm"
-version = "0.12.4"
+version = "0.12.5"
 dependencies = [
  "console_error_panic_hook",
  "console_log",
@@ -3535,9 +3558,9 @@ dependencies = [
 
 [[package]]
 name = "serde_json"
-version = "1.0.140"
+version = "1.0.141"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "20068b6e96dc6c9bd23e01df8827e6c7e1f2fddd43c21810382803c136b99373"
+checksum = "30b9eff21ebe718216c6ec64e1d9ac57087aad11efc64e32002bce4a0d4c03d3"
 dependencies = [
  "itoa",
  "memchr",
@@ -3727,23 +3750,22 @@ checksum = "7da8b5736845d9f2fcb837ea5d9e2628564b3b043a70948a3f0b778838c5fb4f"
 
 [[package]]
 name = "strum"
-version = "0.27.1"
+version = "0.27.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f64def088c51c9510a8579e3c5d67c65349dcf755e5479ad3d010aa6454e2c32"
+checksum = "af23d6f6c1a224baef9d3f61e287d2761385a5b88fdab4eb4c6f11aeb54c4bcf"
 dependencies = [
  "strum_macros",
 ]
 
 [[package]]
 name = "strum_macros"
-version = "0.27.1"
+version = "0.27.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c77a8c5abcaf0f9ce05d62342b7d298c346515365c36b673df4ebe3ced01fde8"
+checksum = "7695ce3845ea4b33927c055a39dc438a45b059f7c1b3d91d38d10355fb8cbca7"
 dependencies = [
  "heck",
  "proc-macro2",
  "quote",
- "rustversion",
  "syn",
 ]
 
@@ -3769,6 +3791,12 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "tap"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "55937e1799185b12863d447f42597ed69d9928686b8d88a1df17376a097d8369"
+
 [[package]]
 name = "tempfile"
 version = "3.20.0"
@@ -4183,6 +4211,7 @@ version = "0.0.0"
 dependencies = [
  "bitflags 2.9.1",
  "insta",
+ "itertools 0.14.0",
  "regex",
  "ruff_db",
  "ruff_python_ast",
@@ -4191,11 +4220,10 @@ dependencies = [
  "ruff_source_file",
  "ruff_text_size",
  "rustc-hash",
- "salsa",
  "smallvec",
  "tracing",
+ "ty_project",
  "ty_python_semantic",
- "ty_vendored",
 ]
 
 [[package]]
@@ -4229,7 +4257,6 @@ dependencies = [
  "thiserror 2.0.12",
  "toml 0.9.2",
  "tracing",
- "ty_ide",
  "ty_python_semantic",
  "ty_vendored",
 ]
@@ -4240,6 +4267,7 @@ version = "0.0.0"
 dependencies = [
  "anyhow",
  "bitflags 2.9.1",
+ "bitvec",
  "camino",
  "colored 3.0.0",
  "compact_str",
@@ -4276,6 +4304,7 @@ dependencies = [
  "strum_macros",
  "tempfile",
  "test-case",
+ "thin-vec",
  "thiserror 2.0.12",
  "tracing",
  "ty_python_semantic",
@@ -4291,10 +4320,13 @@ dependencies = [
  "anyhow",
  "bitflags 2.9.1",
  "crossbeam",
+ "dunce",
+ "insta",
  "jod-thread",
  "libc",
  "lsp-server",
  "lsp-types",
+ "regex",
  "ruff_db",
  "ruff_notebook",
  "ruff_python_ast",
@@ -4305,6 +4337,7 @@ dependencies = [
  "serde",
  "serde_json",
  "shellexpand",
+ "tempfile",
  "thiserror 2.0.12",
  "tracing",
  "tracing-subscriber",
@@ -4564,7 +4597,7 @@ checksum = "3cf4199d1e5d15ddd86a694e4d0dffa9c323ce759fea589f00fef9d81cc1931d"
 dependencies = [
  "getrandom 0.3.3",
  "js-sys",
- "rand 0.9.1",
+ "rand 0.9.2",
  "uuid-macro-internal",
  "wasm-bindgen",
 ]
@@ -5093,6 +5126,15 @@ version = "0.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ea2f10b9bb0928dfb1b42b65e1f9e36f7f54dbdf08457afefb38afcdec4fa2bb"
 
+[[package]]
+name = "wyz"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "05f360fc0b24296329c78fda852a1e9ae82de9cf7b27dae4b7f62f118f77b9ed"
+dependencies = [
+ "tap",
+]
+
 [[package]]
 name = "yansi"
 version = "1.0.1"

Cargo.toml

@@ -57,6 +57,9 @@ assert_fs = { version = "1.1.0" }
 argfile = { version = "0.2.0" }
 bincode = { version = "2.0.0" }
 bitflags = { version = "2.5.0" }
+bitvec = { version = "1.0.1", default-features = false, features = [
+    "alloc",
+] }
 bstr = { version = "1.9.1" }
 cachedir = { version = "0.3.1" }
 camino = { version = "1.1.7" }
@@ -163,6 +166,7 @@ strum_macros = { version = "0.27.0" }
 syn = { version = "2.0.55" }
 tempfile = { version = "3.9.0" }
 test-case = { version = "3.3.1" }
+thin-vec = { version = "0.2.14" }
 thiserror = { version = "2.0.0" }
 tikv-jemallocator = { version = "0.6.0" }
 toml = { version = "0.9.0" }

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/0.12.4/install.sh | sh
-powershell -c "irm https://astral.sh/ruff/0.12.4/install.ps1 | iex"
+curl -LsSf https://astral.sh/ruff/0.12.5/install.sh | sh
+powershell -c "irm https://astral.sh/ruff/0.12.5/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: v0.12.4
+  rev: v0.12.5
   hooks:
     # Run the linter.
     - id: ruff-check

crates/ruff/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ruff"
-version = "0.12.4"
+version = "0.12.5"
 publish = true
 authors = { workspace = true }
 edition = { workspace = true }

crates/ruff/src/cache.rs

@@ -454,7 +454,7 @@ impl LintCacheData {
                 CacheMessage {
                     rule,
                     body: msg.body().to_string(),
-                    suggestion: msg.suggestion().map(ToString::to_string),
+                    suggestion: msg.first_help_text().map(ToString::to_string),
                     range: msg.expect_range(),
                     parent: msg.parent(),
                     fix: msg.fix().cloned(),

crates/ruff/src/printer.rs

@@ -264,6 +264,7 @@ impl Printer {
                     .with_show_fix_diff(self.flags.intersects(Flags::SHOW_FIX_DIFF))
                     .with_show_source(self.format == OutputFormat::Full)
                     .with_unsafe_fixes(self.unsafe_fixes)
+                    .with_preview(preview)
                     .emit(writer, &diagnostics.inner, &context)?;
 
                 if self.flags.intersects(Flags::SHOW_FIX_SUMMARY) {

crates/ruff_db/Cargo.toml

@@ -25,7 +25,6 @@ ty_static = { workspace = true }
 anstyle = { workspace = true }
 arc-swap = { workspace = true }
 camino = { workspace = true }
-countme = { workspace = true }
 dashmap = { workspace = true }
 dunce = { workspace = true }
 filetime = { workspace = true }
@@ -59,6 +58,11 @@ tempfile = { workspace = true }
 cache = ["ruff_cache"]
 junit = ["dep:quick-junit"]
 os = ["ignore", "dep:etcetera"]
-serde = ["camino/serde1", "dep:serde", "dep:serde_json", "ruff_diagnostics/serde"]
+serde = [
+    "camino/serde1",
+    "dep:serde",
+    "dep:serde_json",
+    "ruff_diagnostics/serde",
+]
 # Exposes testing utilities.
 testing = ["tracing-subscriber"]

crates/ruff_db/src/diagnostic/mod.rs

@@ -1,6 +1,6 @@
 use std::{fmt::Formatter, path::Path, sync::Arc};
 
-use ruff_diagnostics::Fix;
+use ruff_diagnostics::{Applicability, Fix};
 use ruff_source_file::{LineColumn, SourceCode, SourceFile};
 
 use ruff_annotate_snippets::Level as AnnotateLevel;
@@ -122,7 +122,14 @@ impl Diagnostic {
     /// directly. If callers want or need to avoid cloning the diagnostic
     /// message, then they can also pass a `DiagnosticMessage` directly.
     pub fn info<'a>(&mut self, message: impl IntoDiagnosticMessage + 'a) {
-        self.sub(SubDiagnostic::new(Severity::Info, message));
+        self.sub(SubDiagnostic::new(SubDiagnosticSeverity::Info, message));
+    }
+
+    /// Adds a "help" sub-diagnostic with the given message.
+    ///
+    /// See the closely related [`Diagnostic::info`] method for more details.
+    pub fn help<'a>(&mut self, message: impl IntoDiagnosticMessage + 'a) {
+        self.sub(SubDiagnostic::new(SubDiagnosticSeverity::Help, message));
     }
 
     /// Adds a "sub" diagnostic to this diagnostic.
@@ -377,9 +384,15 @@ impl Diagnostic {
         self.primary_message()
     }
 
-    /// Returns the fix suggestion for the violation.
-    pub fn suggestion(&self) -> Option<&str> {
-        self.primary_annotation()?.get_message()
+    /// Returns the message of the first sub-diagnostic with a `Help` severity.
+    ///
+    /// Note that this is used as the fix title/suggestion for some of Ruff's output formats, but in
+    /// general this is not the guaranteed meaning of such a message.
+    pub fn first_help_text(&self) -> Option<&str> {
+        self.sub_diagnostics()
+            .iter()
+            .find(|sub| matches!(sub.inner.severity, SubDiagnosticSeverity::Help))
+            .map(|sub| sub.inner.message.as_str())
     }
 
     /// Returns the URL for the rule documentation, if it exists.
@@ -565,7 +578,10 @@ impl SubDiagnostic {
     /// Callers can pass anything that implements `std::fmt::Display`
     /// directly. If callers want or need to avoid cloning the diagnostic
     /// message, then they can also pass a `DiagnosticMessage` directly.
-    pub fn new<'a>(severity: Severity, message: impl IntoDiagnosticMessage + 'a) -> SubDiagnostic {
+    pub fn new<'a>(
+        severity: SubDiagnosticSeverity,
+        message: impl IntoDiagnosticMessage + 'a,
+    ) -> SubDiagnostic {
         let inner = Box::new(SubDiagnosticInner {
             severity,
             message: message.into_diagnostic_message(),
@@ -643,7 +659,7 @@ impl SubDiagnostic {
 
 #[derive(Debug, Clone, Eq, PartialEq, get_size2::GetSize)]
 struct SubDiagnosticInner {
-    severity: Severity,
+    severity: SubDiagnosticSeverity,
     message: DiagnosticMessage,
     annotations: Vec<Annotation>,
 }
@@ -1170,6 +1186,32 @@ impl Severity {
     }
 }
 
+/// Like [`Severity`] but exclusively for sub-diagnostics.
+///
+/// This type only exists to add an additional `Help` severity that isn't present in `Severity` or
+/// used for main diagnostics. If we want to add `Severity::Help` in the future, this type could be
+/// deleted and the two combined again.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Ord, PartialOrd, get_size2::GetSize)]
+pub enum SubDiagnosticSeverity {
+    Help,
+    Info,
+    Warning,
+    Error,
+    Fatal,
+}
+
+impl SubDiagnosticSeverity {
+    fn to_annotate(self) -> AnnotateLevel {
+        match self {
+            SubDiagnosticSeverity::Help => AnnotateLevel::Help,
+            SubDiagnosticSeverity::Info => AnnotateLevel::Info,
+            SubDiagnosticSeverity::Warning => AnnotateLevel::Warning,
+            SubDiagnosticSeverity::Error => AnnotateLevel::Error,
+            SubDiagnosticSeverity::Fatal => AnnotateLevel::Error,
+        }
+    }
+}
+
 /// Configuration for rendering diagnostics.
 #[derive(Clone, Debug)]
 pub struct DisplayDiagnosticConfig {
@@ -1196,6 +1238,15 @@ pub struct DisplayDiagnosticConfig {
         reason = "This is currently only used for JSON but will be needed soon for other formats"
     )]
     preview: bool,
+    /// Whether to hide the real `Severity` of diagnostics.
+    ///
+    /// This is intended for temporary use by Ruff, which only has a single `error` severity at the
+    /// moment. We should be able to remove this option when Ruff gets more severities.
+    hide_severity: bool,
+    /// Whether to show the availability of a fix in a diagnostic.
+    show_fix_status: bool,
+    /// The lowest applicability that should be shown when reporting diagnostics.
+    fix_applicability: Applicability,
 }
 
 impl DisplayDiagnosticConfig {
@@ -1224,6 +1275,35 @@ impl DisplayDiagnosticConfig {
             ..self
         }
     }
+
+    /// Whether to hide a diagnostic's severity or not.
+    pub fn hide_severity(self, yes: bool) -> DisplayDiagnosticConfig {
+        DisplayDiagnosticConfig {
+            hide_severity: yes,
+            ..self
+        }
+    }
+
+    /// Whether to show a fix's availability or not.
+    pub fn show_fix_status(self, yes: bool) -> DisplayDiagnosticConfig {
+        DisplayDiagnosticConfig {
+            show_fix_status: yes,
+            ..self
+        }
+    }
+
+    /// Set the lowest fix applicability that should be shown.
+    ///
+    /// In other words, an applicability of `Safe` (the default) would suppress showing fixes or fix
+    /// availability for unsafe or display-only fixes.
+    ///
+    /// Note that this option is currently ignored when `hide_severity` is false.
+    pub fn fix_applicability(self, applicability: Applicability) -> DisplayDiagnosticConfig {
+        DisplayDiagnosticConfig {
+            fix_applicability: applicability,
+            ..self
+        }
+    }
 }
 
 impl Default for DisplayDiagnosticConfig {
@@ -1233,6 +1313,9 @@ impl Default for DisplayDiagnosticConfig {
             color: false,
             context: 2,
             preview: false,
+            hide_severity: false,
+            show_fix_status: false,
+            fix_applicability: Applicability::Safe,
         }
     }
 }

crates/ruff_db/src/diagnostic/render.rs

@@ -9,7 +9,7 @@ use ruff_notebook::{Notebook, NotebookIndex};
 use ruff_source_file::{LineIndex, OneIndexed, SourceCode};
 use ruff_text_size::{TextRange, TextSize};
 
-use crate::diagnostic::stylesheet::{DiagnosticStylesheet, fmt_styled};
+use crate::diagnostic::stylesheet::DiagnosticStylesheet;
 use crate::{
     Db,
     files::File,
@@ -18,14 +18,17 @@ use crate::{
 };
 
 use super::{
-    Annotation, Diagnostic, DiagnosticFormat, DiagnosticSource, DisplayDiagnosticConfig, Severity,
+    Annotation, Diagnostic, DiagnosticFormat, DiagnosticSource, DisplayDiagnosticConfig,
     SubDiagnostic, UnifiedFile,
 };
 
 use azure::AzureRenderer;
+use concise::ConciseRenderer;
 use pylint::PylintRenderer;
 
 mod azure;
+mod concise;
+mod full;
 #[cfg(feature = "serde")]
 mod json;
 #[cfg(feature = "serde")]
@@ -104,48 +107,7 @@ impl std::fmt::Display for DisplayDiagnostics<'_> {
     fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
         match self.config.format {
             DiagnosticFormat::Concise => {
-                let stylesheet = if self.config.color {
-                    DiagnosticStylesheet::styled()
-                } else {
-                    DiagnosticStylesheet::plain()
-                };
-
-                for diag in self.diagnostics {
-                    let (severity, severity_style) = match diag.severity() {
-                        Severity::Info => ("info", stylesheet.info),
-                        Severity::Warning => ("warning", stylesheet.warning),
-                        Severity::Error => ("error", stylesheet.error),
-                        Severity::Fatal => ("fatal", stylesheet.error),
-                    };
-                    write!(
-                        f,
-                        "{severity}[{id}]",
-                        severity = fmt_styled(severity, severity_style),
-                        id = fmt_styled(diag.id(), stylesheet.emphasis)
-                    )?;
-                    if let Some(span) = diag.primary_span() {
-                        write!(
-                            f,
-                            " {path}",
-                            path = fmt_styled(span.file().path(self.resolver), stylesheet.emphasis)
-                        )?;
-                        if let Some(range) = span.range() {
-                            let diagnostic_source = span.file().diagnostic_source(self.resolver);
-                            let start = diagnostic_source
-                                .as_source_code()
-                                .line_column(range.start());
-
-                            write!(
-                                f,
-                                ":{line}:{col}",
-                                line = fmt_styled(start.line, stylesheet.emphasis),
-                                col = fmt_styled(start.column, stylesheet.emphasis),
-                            )?;
-                        }
-                        write!(f, ":")?;
-                    }
-                    writeln!(f, " {message}", message = diag.concise_message())?;
-                }
+                ConciseRenderer::new(self.resolver, self.config).render(f, self.diagnostics)?;
             }
             DiagnosticFormat::Full => {
                 let stylesheet = if self.config.color {
@@ -256,7 +218,7 @@ impl<'a> Resolved<'a> {
 /// both.)
 #[derive(Debug)]
 struct ResolvedDiagnostic<'a> {
-    severity: Severity,
+    level: AnnotateLevel,
     id: Option<String>,
     message: String,
     annotations: Vec<ResolvedAnnotation<'a>>,
@@ -281,7 +243,7 @@ impl<'a> ResolvedDiagnostic<'a> {
         let id = Some(diag.inner.id.to_string());
         let message = diag.inner.message.as_str().to_string();
         ResolvedDiagnostic {
-            severity: diag.inner.severity,
+            level: diag.inner.severity.to_annotate(),
             id,
             message,
             annotations,
@@ -304,7 +266,7 @@ impl<'a> ResolvedDiagnostic<'a> {
             })
             .collect();
         ResolvedDiagnostic {
-            severity: diag.inner.severity,
+            level: diag.inner.severity.to_annotate(),
             id: None,
             message: diag.inner.message.as_str().to_string(),
             annotations,
@@ -371,7 +333,7 @@ impl<'a> ResolvedDiagnostic<'a> {
         snippets_by_input
             .sort_by(|snips1, snips2| snips1.has_primary.cmp(&snips2.has_primary).reverse());
         RenderableDiagnostic {
-            severity: self.severity,
+            level: self.level,
             id: self.id.as_deref(),
             message: &self.message,
             snippets_by_input,
@@ -459,7 +421,7 @@ struct Renderable<'r> {
 #[derive(Debug)]
 struct RenderableDiagnostic<'r> {
     /// The severity of the diagnostic.
-    severity: Severity,
+    level: AnnotateLevel,
     /// The ID of the diagnostic. The ID can usually be used on the CLI or in a
     /// config file to change the severity of a lint.
     ///
@@ -478,7 +440,6 @@ struct RenderableDiagnostic<'r> {
 impl RenderableDiagnostic<'_> {
     /// Convert this to an "annotate" snippet.
     fn to_annotate(&self) -> AnnotateMessage<'_> {
-        let level = self.severity.to_annotate();
         let snippets = self.snippets_by_input.iter().flat_map(|snippets| {
             let path = snippets.path;
             snippets
@@ -486,7 +447,7 @@ impl RenderableDiagnostic<'_> {
                 .iter()
                 .map(|snippet| snippet.to_annotate(path))
         });
-        let mut message = level.title(self.message);
+        let mut message = self.level.title(self.message);
         if let Some(id) = self.id {
             message = message.id(id);
         }
@@ -862,9 +823,12 @@ fn relativize_path<'p>(cwd: &SystemPath, path: &'p str) -> &'p str {
 #[cfg(test)]
 mod tests {
 
-    use ruff_diagnostics::{Edit, Fix};
+    use ruff_diagnostics::{Applicability, Edit, Fix};
 
-    use crate::diagnostic::{Annotation, DiagnosticId, SecondaryCode, Severity, Span};
+    use crate::diagnostic::{
+        Annotation, DiagnosticId, IntoDiagnosticMessage, SecondaryCode, Severity, Span,
+        SubDiagnosticSeverity,
+    };
     use crate::files::system_path_to_file;
     use crate::system::{DbWithWritableSystem, SystemPath};
     use crate::tests::TestDb;
@@ -1548,7 +1512,7 @@ watermelon
 
         let mut diag = env.err().primary("animals", "3", "3", "").build();
         diag.sub(
-            env.sub_builder(Severity::Info, "this is a helpful note")
+            env.sub_builder(SubDiagnosticSeverity::Info, "this is a helpful note")
                 .build(),
         );
         insta::assert_snapshot!(
@@ -1577,15 +1541,15 @@ watermelon
 
         let mut diag = env.err().primary("animals", "3", "3", "").build();
         diag.sub(
-            env.sub_builder(Severity::Info, "this is a helpful note")
+            env.sub_builder(SubDiagnosticSeverity::Info, "this is a helpful note")
                 .build(),
         );
         diag.sub(
-            env.sub_builder(Severity::Info, "another helpful note")
+            env.sub_builder(SubDiagnosticSeverity::Info, "another helpful note")
                 .build(),
         );
         diag.sub(
-            env.sub_builder(Severity::Info, "and another helpful note")
+            env.sub_builder(SubDiagnosticSeverity::Info, "and another helpful note")
                 .build(),
         );
         insta::assert_snapshot!(
@@ -2307,6 +2271,27 @@ watermelon
             self.config = config;
         }
 
+        /// Hide diagnostic severity when rendering.
+        pub(super) fn hide_severity(&mut self, yes: bool) {
+            let mut config = std::mem::take(&mut self.config);
+            config = config.hide_severity(yes);
+            self.config = config;
+        }
+
+        /// Show fix availability when rendering.
+        pub(super) fn show_fix_status(&mut self, yes: bool) {
+            let mut config = std::mem::take(&mut self.config);
+            config = config.show_fix_status(yes);
+            self.config = config;
+        }
+
+        /// The lowest fix applicability to show when rendering.
+        pub(super) fn fix_applicability(&mut self, applicability: Applicability) {
+            let mut config = std::mem::take(&mut self.config);
+            config = config.fix_applicability(applicability);
+            self.config = config;
+        }
+
         /// Add a file with the given path and contents to this environment.
         pub(super) fn add(&mut self, path: &str, contents: &str) {
             let path = SystemPath::new(path);
@@ -2370,7 +2355,7 @@ watermelon
         /// sub-diagnostic with "error" severity and canned values for
         /// its identifier and message.
         fn sub_warn(&mut self) -> SubDiagnosticBuilder<'_> {
-            self.sub_builder(Severity::Warning, "sub-diagnostic message")
+            self.sub_builder(SubDiagnosticSeverity::Warning, "sub-diagnostic message")
         }
 
         /// Returns a builder for tersely constructing diagnostics.
@@ -2391,7 +2376,11 @@ watermelon
         }
 
         /// Returns a builder for tersely constructing sub-diagnostics.
-        fn sub_builder(&mut self, severity: Severity, message: &str) -> SubDiagnosticBuilder<'_> {
+        fn sub_builder(
+            &mut self,
+            severity: SubDiagnosticSeverity,
+            message: &str,
+        ) -> SubDiagnosticBuilder<'_> {
             let subdiag = SubDiagnostic::new(severity, message);
             SubDiagnosticBuilder { env: self, subdiag }
         }
@@ -2494,6 +2483,12 @@ watermelon
             self.diag.set_noqa_offset(noqa_offset);
             self
         }
+
+        /// Adds a "help" sub-diagnostic with the given message.
+        fn help(mut self, message: impl IntoDiagnosticMessage) -> DiagnosticBuilder<'e> {
+            self.diag.help(message);
+            self
+        }
     }
 
     /// A helper builder for tersely populating a `SubDiagnostic`.
@@ -2600,7 +2595,8 @@ def fibonacci(n):
 
         let diagnostics = vec![
             env.builder("unused-import", Severity::Error, "`os` imported but unused")
-                .primary("fib.py", "1:7", "1:9", "Remove unused import: `os`")
+                .primary("fib.py", "1:7", "1:9", "")
+                .help("Remove unused import: `os`")
                 .secondary_code("F401")
                 .fix(Fix::unsafe_edit(Edit::range_deletion(TextRange::new(
                     TextSize::from(0),
@@ -2613,12 +2609,8 @@ def fibonacci(n):
                 Severity::Error,
                 "Local variable `x` is assigned to but never used",
             )
-            .primary(
-                "fib.py",
-                "6:4",
-                "6:5",
-                "Remove assignment to unused variable `x`",
-            )
+            .primary("fib.py", "6:4", "6:5", "")
+            .help("Remove assignment to unused variable `x`")
             .secondary_code("F841")
             .fix(Fix::unsafe_edit(Edit::deletion(
                 TextSize::from(94),
@@ -2665,6 +2657,25 @@ if call(foo
     }
 
     /// Create Ruff-style diagnostics for testing the various output formats for a notebook.
+    ///
+    /// The concatenated cells look like this:
+    ///
+    /// ```python
+    /// # cell 1
+    /// import os
+    /// # cell 2
+    /// import math
+    ///
+    /// print('hello world')
+    /// # cell 3
+    /// def foo():
+    ///     print()
+    ///     x = 1
+    /// ```
+    ///
+    /// The first diagnostic is on the unused `os` import with location cell 1, row 2, column 8
+    /// (`cell 1:2:8`). The second diagnostic is the unused `math` import at `cell 2:2:8`, and the
+    /// third diagnostic is an unfixable unused variable at `cell 3:4:5`.
     #[allow(
         dead_code,
         reason = "This is currently only used for JSON but will be needed soon for other formats"
@@ -2720,7 +2731,8 @@ if call(foo
 
         let diagnostics = vec![
             env.builder("unused-import", Severity::Error, "`os` imported but unused")
-                .primary("notebook.ipynb", "2:7", "2:9", "Remove unused import: `os`")
+                .primary("notebook.ipynb", "2:7", "2:9", "")
+                .help("Remove unused import: `os`")
                 .secondary_code("F401")
                 .fix(Fix::safe_edit(Edit::range_deletion(TextRange::new(
                     TextSize::from(9),
@@ -2733,12 +2745,8 @@ if call(foo
                 Severity::Error,
                 "`math` imported but unused",
             )
-            .primary(
-                "notebook.ipynb",
-                "4:7",
-                "4:11",
-                "Remove unused import: `math`",
-            )
+            .primary("notebook.ipynb", "4:7", "4:11", "")
+            .help("Remove unused import: `math`")
             .secondary_code("F401")
             .fix(Fix::safe_edit(Edit::range_deletion(TextRange::new(
                 TextSize::from(28),
@@ -2751,12 +2759,8 @@ if call(foo
                 Severity::Error,
                 "Local variable `x` is assigned to but never used",
             )
-            .primary(
-                "notebook.ipynb",
-                "10:4",
-                "10:5",
-                "Remove assignment to unused variable `x`",
-            )
+            .primary("notebook.ipynb", "10:4", "10:5", "")
+            .help("Remove assignment to unused variable `x`")
             .secondary_code("F841")
             .fix(Fix::unsafe_edit(Edit::range_deletion(TextRange::new(
                 TextSize::from(94),

crates/ruff_db/src/diagnostic/render/concise.rs

@@ -0,0 +1,195 @@
+use crate::diagnostic::{
+    Diagnostic, DisplayDiagnosticConfig, Severity,
+    stylesheet::{DiagnosticStylesheet, fmt_styled},
+};
+
+use super::FileResolver;
+
+pub(super) struct ConciseRenderer<'a> {
+    resolver: &'a dyn FileResolver,
+    config: &'a DisplayDiagnosticConfig,
+}
+
+impl<'a> ConciseRenderer<'a> {
+    pub(super) fn new(resolver: &'a dyn FileResolver, config: &'a DisplayDiagnosticConfig) -> Self {
+        Self { resolver, config }
+    }
+
+    pub(super) fn render(
+        &self,
+        f: &mut std::fmt::Formatter,
+        diagnostics: &[Diagnostic],
+    ) -> std::fmt::Result {
+        let stylesheet = if self.config.color {
+            DiagnosticStylesheet::styled()
+        } else {
+            DiagnosticStylesheet::plain()
+        };
+
+        let sep = fmt_styled(":", stylesheet.separator);
+        for diag in diagnostics {
+            if let Some(span) = diag.primary_span() {
+                write!(
+                    f,
+                    "{path}",
+                    path = fmt_styled(
+                        span.file().relative_path(self.resolver).to_string_lossy(),
+                        stylesheet.emphasis
+                    )
+                )?;
+                if let Some(range) = span.range() {
+                    let diagnostic_source = span.file().diagnostic_source(self.resolver);
+                    let start = diagnostic_source
+                        .as_source_code()
+                        .line_column(range.start());
+
+                    if let Some(notebook_index) = self.resolver.notebook_index(span.file()) {
+                        write!(
+                            f,
+                            "{sep}cell {cell}{sep}{line}{sep}{col}",
+                            cell = notebook_index.cell(start.line).unwrap_or_default(),
+                            line = notebook_index.cell_row(start.line).unwrap_or_default(),
+                            col = start.column,
+                        )?;
+                    } else {
+                        write!(
+                            f,
+                            "{sep}{line}{sep}{col}",
+                            line = start.line,
+                            col = start.column,
+                        )?;
+                    }
+                }
+                write!(f, "{sep} ")?;
+            }
+            if self.config.hide_severity {
+                if let Some(code) = diag.secondary_code() {
+                    write!(
+                        f,
+                        "{code} ",
+                        code = fmt_styled(code, stylesheet.secondary_code)
+                    )?;
+                }
+                if self.config.show_fix_status {
+                    if let Some(fix) = diag.fix() {
+                        // Do not display an indicator for inapplicable fixes
+                        if fix.applies(self.config.fix_applicability) {
+                            write!(f, "[{fix}] ", fix = fmt_styled("*", stylesheet.separator))?;
+                        }
+                    }
+                }
+            } else {
+                let (severity, severity_style) = match diag.severity() {
+                    Severity::Info => ("info", stylesheet.info),
+                    Severity::Warning => ("warning", stylesheet.warning),
+                    Severity::Error => ("error", stylesheet.error),
+                    Severity::Fatal => ("fatal", stylesheet.error),
+                };
+                write!(
+                    f,
+                    "{severity}[{id}] ",
+                    severity = fmt_styled(severity, severity_style),
+                    id = fmt_styled(diag.id(), stylesheet.emphasis)
+                )?;
+            }
+
+            writeln!(f, "{message}", message = diag.concise_message())?;
+        }
+
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use ruff_diagnostics::Applicability;
+
+    use crate::diagnostic::{
+        DiagnosticFormat,
+        render::tests::{
+            TestEnvironment, create_diagnostics, create_notebook_diagnostics,
+            create_syntax_error_diagnostics,
+        },
+    };
+
+    #[test]
+    fn output() {
+        let (env, diagnostics) = create_diagnostics(DiagnosticFormat::Concise);
+        insta::assert_snapshot!(env.render_diagnostics(&diagnostics), @r"
+        fib.py:1:8: error[unused-import] `os` imported but unused
+        fib.py:6:5: error[unused-variable] Local variable `x` is assigned to but never used
+        undef.py:1:4: error[undefined-name] Undefined name `a`
+        ");
+    }
+
+    #[test]
+    fn show_fixes() {
+        let (mut env, diagnostics) = create_diagnostics(DiagnosticFormat::Concise);
+        env.hide_severity(true);
+        env.show_fix_status(true);
+        env.fix_applicability(Applicability::DisplayOnly);
+        insta::assert_snapshot!(env.render_diagnostics(&diagnostics), @r"
+        fib.py:1:8: F401 [*] `os` imported but unused
+        fib.py:6:5: F841 [*] Local variable `x` is assigned to but never used
+        undef.py:1:4: F821 Undefined name `a`
+        ");
+    }
+
+    #[test]
+    fn show_fixes_preview() {
+        let (mut env, diagnostics) = create_diagnostics(DiagnosticFormat::Concise);
+        env.hide_severity(true);
+        env.show_fix_status(true);
+        env.fix_applicability(Applicability::DisplayOnly);
+        env.preview(true);
+        insta::assert_snapshot!(env.render_diagnostics(&diagnostics), @r"
+        fib.py:1:8: F401 [*] `os` imported but unused
+        fib.py:6:5: F841 [*] Local variable `x` is assigned to but never used
+        undef.py:1:4: F821 Undefined name `a`
+        ");
+    }
+
+    #[test]
+    fn show_fixes_syntax_errors() {
+        let (mut env, diagnostics) = create_syntax_error_diagnostics(DiagnosticFormat::Concise);
+        env.hide_severity(true);
+        env.show_fix_status(true);
+        env.fix_applicability(Applicability::DisplayOnly);
+        insta::assert_snapshot!(env.render_diagnostics(&diagnostics), @r"
+        syntax_errors.py:1:15: SyntaxError: Expected one or more symbol names after import
+        syntax_errors.py:3:12: SyntaxError: Expected ')', found newline
+        ");
+    }
+
+    #[test]
+    fn syntax_errors() {
+        let (env, diagnostics) = create_syntax_error_diagnostics(DiagnosticFormat::Concise);
+        insta::assert_snapshot!(env.render_diagnostics(&diagnostics), @r"
+        syntax_errors.py:1:15: error[invalid-syntax] SyntaxError: Expected one or more symbol names after import
+        syntax_errors.py:3:12: error[invalid-syntax] SyntaxError: Expected ')', found newline
+        ");
+    }
+
+    #[test]
+    fn notebook_output() {
+        let (env, diagnostics) = create_notebook_diagnostics(DiagnosticFormat::Concise);
+        insta::assert_snapshot!(env.render_diagnostics(&diagnostics), @r"
+        notebook.ipynb:cell 1:2:8: error[unused-import] `os` imported but unused
+        notebook.ipynb:cell 2:2:8: error[unused-import] `math` imported but unused
+        notebook.ipynb:cell 3:4:5: error[unused-variable] Local variable `x` is assigned to but never used
+        ");
+    }
+
+    #[test]
+    fn missing_file() {
+        let mut env = TestEnvironment::new();
+        env.format(DiagnosticFormat::Concise);
+
+        let diag = env.err().build();
+
+        insta::assert_snapshot!(
+            env.render(&diag),
+            @"error[test-diagnostic] main diagnostic message",
+        );
+    }
+}

crates/ruff_db/src/diagnostic/render/full.rs

@@ -0,0 +1,66 @@
+#[cfg(test)]
+mod tests {
+    use crate::diagnostic::{
+        DiagnosticFormat,
+        render::tests::{create_diagnostics, create_syntax_error_diagnostics},
+    };
+
+    #[test]
+    fn output() {
+        let (env, diagnostics) = create_diagnostics(DiagnosticFormat::Full);
+        insta::assert_snapshot!(env.render_diagnostics(&diagnostics), @r#"
+        error[unused-import]: `os` imported but unused
+         --> fib.py:1:8
+          |
+        1 | import os
+          |        ^^
+          |
+        help: Remove unused import: `os`
+
+        error[unused-variable]: Local variable `x` is assigned to but never used
+         --> fib.py:6:5
+          |
+        4 | def fibonacci(n):
+        5 |     """Compute the nth number in the Fibonacci sequence."""
+        6 |     x = 1
+          |     ^
+        7 |     if n == 0:
+        8 |         return 0
+          |
+        help: Remove assignment to unused variable `x`
+
+        error[undefined-name]: Undefined name `a`
+         --> undef.py:1:4
+          |
+        1 | if a == 1: pass
+          |    ^
+          |
+        "#);
+    }
+
+    #[test]
+    fn syntax_errors() {
+        let (env, diagnostics) = create_syntax_error_diagnostics(DiagnosticFormat::Full);
+        insta::assert_snapshot!(env.render_diagnostics(&diagnostics), @r"
+        error[invalid-syntax]: SyntaxError: Expected one or more symbol names after import
+         --> syntax_errors.py:1:15
+          |
+        1 | from os import
+          |               ^
+        2 |
+        3 | if call(foo
+          |
+
+        error[invalid-syntax]: SyntaxError: Expected ')', found newline
+         --> syntax_errors.py:3:12
+          |
+        1 | from os import
+        2 |
+        3 | if call(foo
+          |            ^
+        4 |     def bar():
+        5 |         pass
+          |
+        ");
+    }
+}

crates/ruff_db/src/diagnostic/render/json.rs

@@ -87,7 +87,7 @@ pub(super) fn diagnostic_to_json<'a>(
 
     let fix = diagnostic.fix().map(|fix| JsonFix {
         applicability: fix.applicability(),
-        message: diagnostic.suggestion(),
+        message: diagnostic.first_help_text(),
         edits: ExpandedEdits {
             edits: fix.edits(),
             notebook_index,

crates/ruff_db/src/diagnostic/stylesheet.rs

@@ -41,6 +41,8 @@ pub struct DiagnosticStylesheet {
     pub(crate) line_no: Style,
     pub(crate) emphasis: Style,
     pub(crate) none: Style,
+    pub(crate) separator: Style,
+    pub(crate) secondary_code: Style,
 }
 
 impl Default for DiagnosticStylesheet {
@@ -62,6 +64,8 @@ impl DiagnosticStylesheet {
             line_no: bright_blue.effects(Effects::BOLD),
             emphasis: Style::new().effects(Effects::BOLD),
             none: Style::new(),
+            separator: AnsiColor::Cyan.on_default(),
+            secondary_code: AnsiColor::Red.on_default().effects(Effects::BOLD),
         }
     }
 
@@ -75,6 +79,8 @@ impl DiagnosticStylesheet {
             line_no: Style::new(),
             emphasis: Style::new(),
             none: Style::new(),
+            separator: Style::new(),
+            secondary_code: Style::new(),
         }
     }
 }

crates/ruff_db/src/files.rs

@@ -1,7 +1,6 @@
 use std::fmt;
 use std::sync::Arc;
 
-use countme::Count;
 use dashmap::mapref::entry::Entry;
 pub use file_root::{FileRoot, FileRootKind};
 pub use path::FilePath;
@@ -312,11 +311,6 @@ pub struct File {
     /// the file has been deleted is to change the status to `Deleted`.
     #[default]
     status: FileStatus,
-
-    /// Counter that counts the number of created file instances and active file instances.
-    /// Only enabled in debug builds.
-    #[default]
-    count: Count<File>,
 }
 
 // The Salsa heap is tracked separately.

crates/ruff_db/src/source.rs

@@ -1,8 +1,6 @@
 use std::ops::Deref;
 use std::sync::Arc;
 
-use countme::Count;
-
 use ruff_notebook::Notebook;
 use ruff_python_ast::PySourceType;
 use ruff_source_file::LineIndex;
@@ -38,11 +36,7 @@ pub fn source_text(db: &dyn Db, file: File) -> SourceText {
     };
 
     SourceText {
-        inner: Arc::new(SourceTextInner {
-            kind,
-            read_error,
-            count: Count::new(),
-        }),
+        inner: Arc::new(SourceTextInner { kind, read_error }),
     }
 }
 
@@ -125,8 +119,6 @@ impl std::fmt::Debug for SourceText {
 
 #[derive(Eq, PartialEq, get_size2::GetSize)]
 struct SourceTextInner {
-    #[get_size(ignore)]
-    count: Count<SourceText>,
     kind: SourceTextKind,
     read_error: Option<SourceTextError>,
 }

crates/ruff_graph/src/resolver.rs

@@ -20,7 +20,7 @@ impl<'a> Resolver<'a> {
         match import {
             CollectedImport::Import(import) => {
                 let module = resolve_module(self.db, &import)?;
-                Some(module.file()?.path(self.db))
+                Some(module.file(self.db)?.path(self.db))
             }
             CollectedImport::ImportFrom(import) => {
                 // Attempt to resolve the member (e.g., given `from foo import bar`, look for `foo.bar`).
@@ -32,7 +32,7 @@ impl<'a> Resolver<'a> {
                     resolve_module(self.db, &parent?)
                 })?;
 
-                Some(module.file()?.path(self.db))
+                Some(module.file(self.db)?.path(self.db))
             }
         }
     }

crates/ruff_linter/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ruff_linter"
-version = "0.12.4"
+version = "0.12.5"
 publish = false
 authors = { workspace = true }
 edition = { workspace = true }

crates/ruff_linter/resources/test/fixtures/flake8_pyi/PYI016.py

@@ -142,3 +142,7 @@ field47: typing.Optional[int] | typing.Optional[dict]
 # avoid reporting twice
 field48: typing.Union[typing.Optional[typing.Union[complex, complex]], complex]
 field49: typing.Optional[complex | complex] | complex
+
+# Regression test for https://github.com/astral-sh/ruff/issues/19403
+# Should throw duplicate union member but not fix
+isinstance(None, typing.Union[None, None])

crates/ruff_linter/resources/test/fixtures/flake8_use_pathlib/import_from.py

@@ -47,3 +47,19 @@ def _():
     from builtin import open
 
     with open(p) as _: ...  # No error
+
+file = "file_1.py"
+
+rename(file, "file_2.py")
+
+rename(
+    # commment 1
+    file, # comment 2
+    "file_2.py"
+    ,
+    # comment 3
+)
+
+rename(file, "file_2.py", src_dir_fd=None, dst_dir_fd=None)
+
+rename(file, "file_2.py", src_dir_fd=1)

crates/ruff_linter/resources/test/fixtures/pep8_naming/N802.py

@@ -84,3 +84,25 @@ class MyRequestHandler(BaseHTTPRequestHandler):
     def dont_GET(self):
         pass
 
+
+from http.server import CGIHTTPRequestHandler
+
+
+class MyCGIRequestHandler(CGIHTTPRequestHandler):
+    def do_OPTIONS(self):
+        pass
+
+    def dont_OPTIONS(self):
+        pass
+
+
+from http.server import SimpleHTTPRequestHandler
+
+
+class MySimpleRequestHandler(SimpleHTTPRequestHandler):
+    def do_OPTIONS(self):
+        pass
+
+    def dont_OPTIONS(self):
+        pass
+

crates/ruff_linter/resources/test/fixtures/perflint/PERF401.py

@@ -278,3 +278,15 @@ def f():
     for i in src:
         if lambda: 0:
             dst.append(i)
+
+def f():
+    i = "xyz"
+    result = []
+    for i in range(3):
+        result.append(x for x in [i])
+
+def f():
+    i = "xyz"
+    result = []
+    for i in range(3):
+        result.append((x for x in [i]))

crates/ruff_linter/resources/test/fixtures/pylint/empty_comment_line_continuation.py

@@ -0,0 +1,5 @@
+#
+x = 0 \
+#
++1
+print(x)

crates/ruff_linter/resources/test/fixtures/ruff/RUF027_0.py

@@ -79,3 +79,8 @@ def in_type_def():
     from typing import cast
     a = 'int'
     cast('f"{a}"','11')
+
+# Regression test for parser bug
+# https://github.com/astral-sh/ruff/issues/18860
+def fuzz_bug():
+    c('{\t"i}')

crates/ruff_linter/resources/test/fixtures/ruff/RUF055_3.py

@@ -0,0 +1,24 @@
+import re
+
+b_src = b"abc"
+
+# Should be replaced with `b_src.replace(rb"x", b"y")`
+re.sub(rb"x", b"y", b_src)
+
+# Should be replaced with `b_src.startswith(rb"abc")`
+if re.match(rb"abc", b_src):
+    pass
+
+# Should be replaced with `rb"x" in b_src`
+if re.search(rb"x", b_src):
+    pass
+
+# Should be replaced with `b_src.split(rb"abc")`
+re.split(rb"abc", b_src)
+
+# Patterns containing metacharacters should NOT be replaced
+re.sub(rb"ab[c]", b"", b_src)
+re.match(rb"ab[c]", b_src)
+re.search(rb"ab[c]", b_src)
+re.fullmatch(rb"ab[c]", b_src)
+re.split(rb"ab[c]", b_src) 

crates/ruff_linter/src/checkers/ast/analyze/expression.rs

@@ -1039,14 +1039,10 @@ pub(crate) fn expression(expr: &Expr, checker: &Checker) {
                 flake8_simplify::rules::zip_dict_keys_and_values(checker, call);
             }
             if checker.any_rule_enabled(&[
-                Rule::OsChmod,
                 Rule::OsMkdir,
                 Rule::OsMakedirs,
-                Rule::OsRename,
-                Rule::OsReplace,
                 Rule::OsStat,
                 Rule::OsPathJoin,
-                Rule::OsPathSamefile,
                 Rule::OsPathSplitext,
                 Rule::BuiltinOpen,
                 Rule::PyPath,
@@ -1112,6 +1108,18 @@ pub(crate) fn expression(expr: &Expr, checker: &Checker) {
                 if checker.is_rule_enabled(Rule::OsGetcwd) {
                     flake8_use_pathlib::rules::os_getcwd(checker, call, segments);
                 }
+                if checker.is_rule_enabled(Rule::OsChmod) {
+                    flake8_use_pathlib::rules::os_chmod(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsRename) {
+                    flake8_use_pathlib::rules::os_rename(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsReplace) {
+                    flake8_use_pathlib::rules::os_replace(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsPathSamefile) {
+                    flake8_use_pathlib::rules::os_path_samefile(checker, call, segments);
+                }
                 if checker.is_rule_enabled(Rule::PathConstructorCurrentDirectory) {
                     flake8_use_pathlib::rules::path_constructor_current_directory(
                         checker, call, segments,

crates/ruff_linter/src/checkers/tokens.rs

@@ -58,7 +58,7 @@ pub(crate) fn check_tokens(
     }
 
     if context.is_rule_enabled(Rule::EmptyComment) {
-        pylint::rules::empty_comments(context, comment_ranges, locator);
+        pylint::rules::empty_comments(context, comment_ranges, locator, indexer);
     }
 
     if context.is_rule_enabled(Rule::AmbiguousUnicodeCharacterComment) {

crates/ruff_linter/src/codes.rs

@@ -920,11 +920,11 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<(RuleGroup, Rule)> {
 
         // flake8-use-pathlib
         (Flake8UsePathlib, "100") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsPathAbspath),
-        (Flake8UsePathlib, "101") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsChmod),
+        (Flake8UsePathlib, "101") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::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, "104") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsRename),
+        (Flake8UsePathlib, "105") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsReplace),
         (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),
@@ -940,7 +940,7 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<(RuleGroup, Rule)> {
         (Flake8UsePathlib, "118") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsPathJoin),
         (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, "121") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsPathSamefile),
         (Flake8UsePathlib, "122") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsPathSplitext),
         (Flake8UsePathlib, "123") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::BuiltinOpen),
         (Flake8UsePathlib, "124") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::PyPath),

crates/ruff_linter/src/message/mod.rs

@@ -75,12 +75,13 @@ where
     );
 
     let span = Span::from(file).with_range(range);
-    let mut annotation = Annotation::primary(span);
-    if let Some(suggestion) = suggestion {
-        annotation = annotation.message(suggestion);
-    }
+    let annotation = Annotation::primary(span);
     diagnostic.annotate(annotation);
 
+    if let Some(suggestion) = suggestion {
+        diagnostic.help(suggestion);
+    }
+
     if let Some(fix) = fix {
         diagnostic.set_fix(fix);
     }

crates/ruff_linter/src/message/text.rs

@@ -6,13 +6,12 @@ use bitflags::bitflags;
 use colored::Colorize;
 use ruff_annotate_snippets::{Level, Renderer, Snippet};
 
-use ruff_db::diagnostic::{Diagnostic, SecondaryCode};
+use ruff_db::diagnostic::{Diagnostic, DiagnosticFormat, DisplayDiagnosticConfig, SecondaryCode};
 use ruff_notebook::NotebookIndex;
-use ruff_source_file::{LineColumn, OneIndexed};
+use ruff_source_file::OneIndexed;
 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};
@@ -21,8 +20,6 @@ use crate::settings::types::UnsafeFixes;
 bitflags! {
     #[derive(Default)]
     struct EmitterFlags: u8 {
-        /// Whether to show the fix status of a diagnostic.
-        const SHOW_FIX_STATUS   = 1 << 0;
         /// Whether to show the diff of a fix, for diagnostics that have a fix.
         const SHOW_FIX_DIFF     = 1 << 1;
         /// Whether to show the source code of a diagnostic.
@@ -30,17 +27,27 @@ bitflags! {
     }
 }
 
-#[derive(Default)]
 pub struct TextEmitter {
     flags: EmitterFlags,
-    unsafe_fixes: UnsafeFixes,
+    config: DisplayDiagnosticConfig,
+}
+
+impl Default for TextEmitter {
+    fn default() -> Self {
+        Self {
+            flags: EmitterFlags::default(),
+            config: DisplayDiagnosticConfig::default()
+                .format(DiagnosticFormat::Concise)
+                .hide_severity(true)
+                .color(!cfg!(test) && colored::control::SHOULD_COLORIZE.should_colorize()),
+        }
+    }
 }
 
 impl TextEmitter {
     #[must_use]
     pub fn with_show_fix_status(mut self, show_fix_status: bool) -> Self {
-        self.flags
-            .set(EmitterFlags::SHOW_FIX_STATUS, show_fix_status);
+        self.config = self.config.show_fix_status(show_fix_status);
         self
     }
 
@@ -58,7 +65,15 @@ impl TextEmitter {
 
     #[must_use]
     pub fn with_unsafe_fixes(mut self, unsafe_fixes: UnsafeFixes) -> Self {
-        self.unsafe_fixes = unsafe_fixes;
+        self.config = self
+            .config
+            .fix_applicability(unsafe_fixes.required_applicability());
+        self
+    }
+
+    #[must_use]
+    pub fn with_preview(mut self, preview: bool) -> Self {
+        self.config = self.config.preview(preview);
         self
     }
 }
@@ -71,51 +86,10 @@ impl Emitter for TextEmitter {
         context: &EmitterContext,
     ) -> anyhow::Result<()> {
         for message in diagnostics {
+            write!(writer, "{}", message.display(context, &self.config))?;
+
             let filename = message.expect_ruff_filename();
-            write!(
-                writer,
-                "{path}{sep}",
-                path = relativize_path(&filename).bold(),
-                sep = ":".cyan(),
-            )?;
-
-            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 {
-                write!(
-                    writer,
-                    "cell {cell}{sep}",
-                    cell = notebook_index
-                        .cell(start_location.line)
-                        .unwrap_or(OneIndexed::MIN),
-                    sep = ":".cyan(),
-                )?;
-
-                LineColumn {
-                    line: notebook_index
-                        .cell_row(start_location.line)
-                        .unwrap_or(OneIndexed::MIN),
-                    column: start_location.column,
-                }
-            } else {
-                start_location
-            };
-
-            writeln!(
-                writer,
-                "{row}{sep}{col}{sep} {code_and_body}",
-                row = diagnostic_location.line,
-                col = diagnostic_location.column,
-                sep = ":".cyan(),
-                code_and_body = RuleCodeAndBody {
-                    message,
-                    show_fix_status: self.flags.intersects(EmitterFlags::SHOW_FIX_STATUS),
-                    unsafe_fixes: self.unsafe_fixes,
-                }
-            )?;
-
             if self.flags.intersects(EmitterFlags::SHOW_SOURCE) {
                 // The `0..0` range is used to highlight file-level diagnostics.
                 if message.expect_range() != TextRange::default() {
@@ -186,7 +160,7 @@ pub(super) struct MessageCodeFrame<'a> {
 
 impl Display for MessageCodeFrame<'_> {
     fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
-        let suggestion = self.message.suggestion();
+        let suggestion = self.message.first_help_text();
         let footers = if let Some(suggestion) = suggestion {
             vec![Level::Help.title(suggestion)]
         } else {

crates/ruff_linter/src/preview.rs

@@ -134,6 +134,26 @@ pub(crate) const fn is_fix_os_path_dirname_enabled(settings: &LinterSettings) ->
     settings.preview.is_enabled()
 }
 
+// https://github.com/astral-sh/ruff/pull/19404
+pub(crate) const fn is_fix_os_chmod_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
+// https://github.com/astral-sh/ruff/pull/19404
+pub(crate) const fn is_fix_os_rename_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
+// https://github.com/astral-sh/ruff/pull/19404
+pub(crate) const fn is_fix_os_replace_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
+// https://github.com/astral-sh/ruff/pull/19404
+pub(crate) const fn is_fix_os_path_samefile_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
 // https://github.com/astral-sh/ruff/pull/19245
 pub(crate) const fn is_fix_os_getcwd_enabled(settings: &LinterSettings) -> bool {
     settings.preview.is_enabled()

crates/ruff_linter/src/rules/flake8_pyi/rules/duplicate_union_member.rs

@@ -64,6 +64,7 @@ pub(crate) fn duplicate_union_member<'a>(checker: &Checker, expr: &'a Expr) {
     let mut diagnostics = Vec::new();
 
     let mut union_type = UnionKind::TypingUnion;
+    let mut optional_present = false;
     // Adds a member to `literal_exprs` if it is a `Literal` annotation
     let mut check_for_duplicate_members = |expr: &'a Expr, parent: &'a Expr| {
         if matches!(parent, Expr::BinOp(_)) {
@@ -74,6 +75,7 @@ pub(crate) fn duplicate_union_member<'a>(checker: &Checker, expr: &'a Expr) {
             && is_optional_type(checker, expr)
         {
             // If the union member is an `Optional`, add a virtual `None` literal.
+            optional_present = true;
             &VIRTUAL_NONE_LITERAL
         } else {
             expr
@@ -87,7 +89,7 @@ pub(crate) fn duplicate_union_member<'a>(checker: &Checker, expr: &'a Expr) {
                 DuplicateUnionMember {
                     duplicate_name: checker.generator().expr(virtual_expr),
                 },
-                // Use the real expression's range for diagnostics,
+                // Use the real expression's range for diagnostics.
                 expr.range(),
             ));
         }
@@ -104,6 +106,13 @@ pub(crate) fn duplicate_union_member<'a>(checker: &Checker, expr: &'a Expr) {
         return;
     }
 
+    // Do not reduce `Union[None, ... None]` to avoid introducing a `TypeError` unintentionally
+    // e.g. `isinstance(None, Union[None, None])`, if reduced to `isinstance(None, None)`, causes
+    // `TypeError: isinstance() arg 2 must be a type, a tuple of types, or a union` to throw.
+    if unique_nodes.iter().all(|expr| expr.is_none_literal_expr()) && !optional_present {
+        return;
+    }
+
     // Mark [`Fix`] as unsafe when comments are in range.
     let applicability = if checker.comment_ranges().intersects(expr.range()) {
         Applicability::Unsafe

crates/ruff_linter/src/rules/flake8_pyi/snapshots/ruff_linter__rules__flake8_pyi__tests__PYI016_PYI016.py.snap

@@ -974,6 +974,8 @@ PYI016.py:143:61: PYI016 [*] Duplicate union member `complex`
 143     |-field48: typing.Union[typing.Optional[typing.Union[complex, complex]], complex]
     143 |+field48: typing.Union[typing.Optional[complex], complex]
 144 144 | field49: typing.Optional[complex | complex] | complex
+145 145 | 
+146 146 | # Regression test for https://github.com/astral-sh/ruff/issues/19403
 
 PYI016.py:144:36: PYI016 [*] Duplicate union member `complex`
     |
@@ -981,6 +983,8 @@ PYI016.py:144:36: PYI016 [*] Duplicate union member `complex`
 143 | field48: typing.Union[typing.Optional[typing.Union[complex, complex]], complex]
 144 | field49: typing.Optional[complex | complex] | complex
     |                                    ^^^^^^^ PYI016
+145 |
+146 | # Regression test for https://github.com/astral-sh/ruff/issues/19403
     |
     = help: Remove duplicate union member `complex`
 
@@ -990,3 +994,15 @@ PYI016.py:144:36: PYI016 [*] Duplicate union member `complex`
 143 143 | field48: typing.Union[typing.Optional[typing.Union[complex, complex]], complex]
 144     |-field49: typing.Optional[complex | complex] | complex
     144 |+field49: typing.Optional[complex] | complex
+145 145 | 
+146 146 | # Regression test for https://github.com/astral-sh/ruff/issues/19403
+147 147 | # Should throw duplicate union member but not fix
+
+PYI016.py:148:37: PYI016 Duplicate union member `None`
+    |
+146 | # Regression test for https://github.com/astral-sh/ruff/issues/19403
+147 | # Should throw duplicate union member but not fix
+148 | isinstance(None, typing.Union[None, None])
+    |                                     ^^^^ PYI016
+    |
+    = help: Remove duplicate union member `None`

crates/ruff_linter/src/rules/flake8_pyi/snapshots/ruff_linter__rules__flake8_pyi__tests__preview__PYI016_PYI016.py.snap

@@ -1162,6 +1162,8 @@ PYI016.py:143:61: PYI016 [*] Duplicate union member `complex`
 143     |-field48: typing.Union[typing.Optional[typing.Union[complex, complex]], complex]
     143 |+field48: typing.Union[None, complex]
 144 144 | field49: typing.Optional[complex | complex] | complex
+145 145 | 
+146 146 | # Regression test for https://github.com/astral-sh/ruff/issues/19403
 
 PYI016.py:143:72: PYI016 [*] Duplicate union member `complex`
     |
@@ -1179,6 +1181,8 @@ PYI016.py:143:72: PYI016 [*] Duplicate union member `complex`
 143     |-field48: typing.Union[typing.Optional[typing.Union[complex, complex]], complex]
     143 |+field48: typing.Union[None, complex]
 144 144 | field49: typing.Optional[complex | complex] | complex
+145 145 | 
+146 146 | # Regression test for https://github.com/astral-sh/ruff/issues/19403
 
 PYI016.py:144:36: PYI016 [*] Duplicate union member `complex`
     |
@@ -1186,6 +1190,8 @@ PYI016.py:144:36: PYI016 [*] Duplicate union member `complex`
 143 | field48: typing.Union[typing.Optional[typing.Union[complex, complex]], complex]
 144 | field49: typing.Optional[complex | complex] | complex
     |                                    ^^^^^^^ PYI016
+145 |
+146 | # Regression test for https://github.com/astral-sh/ruff/issues/19403
     |
     = help: Remove duplicate union member `complex`
 
@@ -1195,6 +1201,9 @@ PYI016.py:144:36: PYI016 [*] Duplicate union member `complex`
 143 143 | field48: typing.Union[typing.Optional[typing.Union[complex, complex]], complex]
 144     |-field49: typing.Optional[complex | complex] | complex
     144 |+field49: None | complex
+145 145 | 
+146 146 | # Regression test for https://github.com/astral-sh/ruff/issues/19403
+147 147 | # Should throw duplicate union member but not fix
 
 PYI016.py:144:47: PYI016 [*] Duplicate union member `complex`
     |
@@ -1202,6 +1211,8 @@ PYI016.py:144:47: PYI016 [*] Duplicate union member `complex`
 143 | field48: typing.Union[typing.Optional[typing.Union[complex, complex]], complex]
 144 | field49: typing.Optional[complex | complex] | complex
     |                                               ^^^^^^^ PYI016
+145 |
+146 | # Regression test for https://github.com/astral-sh/ruff/issues/19403
     |
     = help: Remove duplicate union member `complex`
 
@@ -1211,3 +1222,15 @@ PYI016.py:144:47: PYI016 [*] Duplicate union member `complex`
 143 143 | field48: typing.Union[typing.Optional[typing.Union[complex, complex]], complex]
 144     |-field49: typing.Optional[complex | complex] | complex
     144 |+field49: None | complex
+145 145 | 
+146 146 | # Regression test for https://github.com/astral-sh/ruff/issues/19403
+147 147 | # Should throw duplicate union member but not fix
+
+PYI016.py:148:37: PYI016 Duplicate union member `None`
+    |
+146 | # Regression test for https://github.com/astral-sh/ruff/issues/19403
+147 | # Should throw duplicate union member but not fix
+148 | isinstance(None, typing.Union[None, None])
+    |                                     ^^^^ PYI016
+    |
+    = help: Remove duplicate union member `None`

crates/ruff_linter/src/rules/flake8_use_pathlib/helpers.rs

@@ -1,8 +1,8 @@
 use crate::checkers::ast::Checker;
 use crate::importer::ImportRequest;
 use crate::{Applicability, Edit, Fix, Violation};
-use ruff_python_ast::{self as ast};
-use ruff_python_ast::{Expr, ExprCall};
+use ruff_python_ast::{self as ast, Expr, ExprCall};
+use ruff_python_semantic::{SemanticModel, analyze::typing};
 use ruff_text_size::Ranged;
 
 pub(crate) fn is_keyword_only_argument_non_default(arguments: &ast::Arguments, name: &str) -> bool {
@@ -72,3 +72,85 @@ pub(crate) fn check_os_pathlib_single_arg_calls(
         });
     }
 }
+
+pub(crate) fn get_name_expr(expr: &Expr) -> Option<&ast::ExprName> {
+    match expr {
+        Expr::Name(name) => Some(name),
+        Expr::Call(ExprCall { func, .. }) => get_name_expr(func),
+        _ => None,
+    }
+}
+
+/// Returns `true` if the given expression looks like a file descriptor, i.e., if it is an integer.
+pub(crate) fn is_file_descriptor(expr: &Expr, semantic: &SemanticModel) -> bool {
+    if matches!(
+        expr,
+        Expr::NumberLiteral(ast::ExprNumberLiteral {
+            value: ast::Number::Int(_),
+            ..
+        })
+    ) {
+        return true;
+    }
+
+    let Some(name) = get_name_expr(expr) else {
+        return false;
+    };
+
+    let Some(binding) = semantic.only_binding(name).map(|id| semantic.binding(id)) else {
+        return false;
+    };
+
+    typing::is_int(binding, semantic)
+}
+
+pub(crate) fn check_os_pathlib_two_arg_calls(
+    checker: &Checker,
+    call: &ExprCall,
+    attr: &str,
+    path_arg: &str,
+    second_arg: &str,
+    fix_enabled: bool,
+    violation: impl Violation,
+) {
+    let range = call.range();
+    let mut diagnostic = checker.report_diagnostic(violation, call.func.range());
+
+    let (Some(path_expr), Some(second_expr)) = (
+        call.arguments.find_argument_value(path_arg, 0),
+        call.arguments.find_argument_value(second_arg, 1),
+    ) else {
+        return;
+    };
+
+    let path_code = checker.locator().slice(path_expr.range());
+    let second_code = checker.locator().slice(second_expr.range());
+
+    if fix_enabled {
+        diagnostic.try_set_fix(|| {
+            let (import_edit, binding) = checker.importer().get_or_import_symbol(
+                &ImportRequest::import("pathlib", "Path"),
+                call.start(),
+                checker.semantic(),
+            )?;
+
+            let replacement = if is_pathlib_path_call(checker, path_expr) {
+                format!("{path_code}.{attr}({second_code})")
+            } else {
+                format!("{binding}({path_code}).{attr}({second_code})")
+            };
+
+            let applicability = if checker.comment_ranges().intersects(range) {
+                Applicability::Unsafe
+            } else {
+                Applicability::Safe
+            };
+
+            Ok(Fix::applicable_edits(
+                Edit::range_replacement(replacement, range),
+                [import_edit],
+                applicability,
+            ))
+        });
+    }
+}

crates/ruff_linter/src/rules/flake8_use_pathlib/rules/mod.rs

@@ -1,5 +1,6 @@
 pub(crate) use glob_rule::*;
 pub(crate) use invalid_pathlib_with_suffix::*;
+pub(crate) use os_chmod::*;
 pub(crate) use os_getcwd::*;
 pub(crate) use os_path_abspath::*;
 pub(crate) use os_path_basename::*;
@@ -14,8 +15,11 @@ pub(crate) use os_path_isabs::*;
 pub(crate) use os_path_isdir::*;
 pub(crate) use os_path_isfile::*;
 pub(crate) use os_path_islink::*;
+pub(crate) use os_path_samefile::*;
 pub(crate) use os_readlink::*;
 pub(crate) use os_remove::*;
+pub(crate) use os_rename::*;
+pub(crate) use os_replace::*;
 pub(crate) use os_rmdir::*;
 pub(crate) use os_sep_split::*;
 pub(crate) use os_unlink::*;
@@ -24,6 +28,7 @@ pub(crate) use replaceable_by_pathlib::*;
 
 mod glob_rule;
 mod invalid_pathlib_with_suffix;
+mod os_chmod;
 mod os_getcwd;
 mod os_path_abspath;
 mod os_path_basename;
@@ -38,8 +43,11 @@ mod os_path_isabs;
 mod os_path_isdir;
 mod os_path_isfile;
 mod os_path_islink;
+mod os_path_samefile;
 mod os_readlink;
 mod os_remove;
+mod os_rename;
+mod os_replace;
 mod os_rmdir;
 mod os_sep_split;
 mod os_unlink;

crates/ruff_linter/src/rules/flake8_use_pathlib/rules/os_chmod.rs

@@ -0,0 +1,94 @@
+use crate::checkers::ast::Checker;
+use crate::preview::is_fix_os_chmod_enabled;
+use crate::rules::flake8_use_pathlib::helpers::{
+    check_os_pathlib_two_arg_calls, is_file_descriptor, is_keyword_only_argument_non_default,
+};
+use crate::{FixAvailability, Violation};
+use ruff_macros::{ViolationMetadata, derive_message_formats};
+use ruff_python_ast::ExprCall;
+
+/// ## What it does
+/// Checks for uses of `os.chmod`.
+///
+/// ## Why is this bad?
+/// `pathlib` offers a high-level API for path manipulation, as compared to
+/// the lower-level API offered by `os`. When possible, using `Path` object
+/// methods such as `Path.chmod()` can improve readability over the `os`
+/// module's counterparts (e.g., `os.chmod()`).
+///
+/// ## Examples
+/// ```python
+/// import os
+///
+/// os.chmod("file.py", 0o444)
+/// ```
+///
+/// Use instead:
+/// ```python
+/// from pathlib import Path
+///
+/// Path("file.py").chmod(0o444)
+/// ```
+///
+/// ## Known issues
+/// While using `pathlib` can improve the readability and type safety of your code,
+/// it can be less performant than the lower-level alternatives that work directly with strings,
+/// especially on older versions of Python.
+///
+/// ## Fix Safety
+/// This rule's fix is marked as unsafe if the replacement would remove comments attached to the original expression.
+///
+/// ## References
+/// - [Python documentation: `Path.chmod`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.chmod)
+/// - [Python documentation: `os.chmod`](https://docs.python.org/3/library/os.html#os.chmod)
+/// - [PEP 428 – The pathlib module – object-oriented filesystem paths](https://peps.python.org/pep-0428/)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#correspondence-to-tools-in-the-os-module)
+/// - [Why you should be using pathlib](https://treyhunner.com/2018/12/why-you-should-be-using-pathlib/)
+/// - [No really, pathlib is great](https://treyhunner.com/2019/01/no-really-pathlib-is-great/)
+#[derive(ViolationMetadata)]
+pub(crate) struct OsChmod;
+
+impl Violation for OsChmod {
+    const FIX_AVAILABILITY: FixAvailability = FixAvailability::Sometimes;
+
+    #[derive_message_formats]
+    fn message(&self) -> String {
+        "`os.chmod()` should be replaced by `Path.chmod()`".to_string()
+    }
+
+    fn fix_title(&self) -> Option<String> {
+        Some("Replace with `Path(...).chmod(...)`".to_string())
+    }
+}
+
+/// PTH101
+pub(crate) fn os_chmod(checker: &Checker, call: &ExprCall, segments: &[&str]) {
+    if segments != ["os", "chmod"] {
+        return;
+    }
+
+    // `dir_fd` is not supported by pathlib, so check if it's set to non-default values.
+    // Signature as of Python 3.13 (https://docs.python.org/3/library/os.html#os.chmod)
+    // ```text
+    //           0     1          2               3
+    // os.chmod(path, mode, *, dir_fd=None, follow_symlinks=True)
+    // ```
+    if call
+        .arguments
+        .find_argument_value("path", 0)
+        .is_some_and(|expr| is_file_descriptor(expr, checker.semantic()))
+        || is_keyword_only_argument_non_default(&call.arguments, "dir_fd")
+    {
+        return;
+    }
+
+    check_os_pathlib_two_arg_calls(
+        checker,
+        call,
+        "chmod",
+        "path",
+        "mode",
+        is_fix_os_chmod_enabled(checker.settings()),
+        OsChmod,
+    );
+}

crates/ruff_linter/src/rules/flake8_use_pathlib/rules/os_path_samefile.rs

@@ -0,0 +1,77 @@
+use crate::checkers::ast::Checker;
+use crate::preview::is_fix_os_path_samefile_enabled;
+use crate::rules::flake8_use_pathlib::helpers::check_os_pathlib_two_arg_calls;
+use crate::{FixAvailability, Violation};
+use ruff_macros::{ViolationMetadata, derive_message_formats};
+use ruff_python_ast::ExprCall;
+
+/// ## What it does
+/// Checks for uses of `os.path.samefile`.
+///
+/// ## Why is this bad?
+/// `pathlib` offers a high-level API for path manipulation, as compared to
+/// the lower-level API offered by `os.path`. When possible, using `Path` object
+/// methods such as `Path.samefile()` can improve readability over the `os.path`
+/// module's counterparts (e.g., `os.path.samefile()`).
+///
+/// ## Examples
+/// ```python
+/// import os
+///
+/// os.path.samefile("f1.py", "f2.py")
+/// ```
+///
+/// Use instead:
+/// ```python
+/// from pathlib import Path
+///
+/// Path("f1.py").samefile("f2.py")
+/// ```
+///
+/// ## Known issues
+/// While using `pathlib` can improve the readability and type safety of your code,
+/// it can be less performant than the lower-level alternatives that work directly with strings,
+/// especially on older versions of Python.
+///
+/// ## Fix Safety
+/// This rule's fix is marked as unsafe if the replacement would remove comments attached to the original expression.
+///
+/// ## References
+/// - [Python documentation: `Path.samefile`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.samefile)
+/// - [Python documentation: `os.path.samefile`](https://docs.python.org/3/library/os.path.html#os.path.samefile)
+/// - [PEP 428 – The pathlib module – object-oriented filesystem paths](https://peps.python.org/pep-0428/)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#correspondence-to-tools-in-the-os-module)
+/// - [Why you should be using pathlib](https://treyhunner.com/2018/12/why-you-should-be-using-pathlib/)
+/// - [No really, pathlib is great](https://treyhunner.com/2019/01/no-really-pathlib-is-great/)
+#[derive(ViolationMetadata)]
+pub(crate) struct OsPathSamefile;
+
+impl Violation for OsPathSamefile {
+    const FIX_AVAILABILITY: FixAvailability = FixAvailability::Sometimes;
+
+    #[derive_message_formats]
+    fn message(&self) -> String {
+        "`os.path.samefile()` should be replaced by `Path.samefile()`".to_string()
+    }
+
+    fn fix_title(&self) -> Option<String> {
+        Some("Replace with `Path(...).samefile()`".to_string())
+    }
+}
+
+/// PTH121
+pub(crate) fn os_path_samefile(checker: &Checker, call: &ExprCall, segments: &[&str]) {
+    if segments != ["os", "path", "samefile"] {
+        return;
+    }
+
+    check_os_pathlib_two_arg_calls(
+        checker,
+        call,
+        "samefile",
+        "f1",
+        "f2",
+        is_fix_os_path_samefile_enabled(checker.settings()),
+        OsPathSamefile,
+    );
+}

crates/ruff_linter/src/rules/flake8_use_pathlib/rules/os_rename.rs

@@ -0,0 +1,91 @@
+use crate::checkers::ast::Checker;
+use crate::preview::is_fix_os_rename_enabled;
+use crate::rules::flake8_use_pathlib::helpers::{
+    check_os_pathlib_two_arg_calls, is_keyword_only_argument_non_default,
+};
+use crate::{FixAvailability, Violation};
+use ruff_macros::{ViolationMetadata, derive_message_formats};
+use ruff_python_ast::ExprCall;
+
+/// ## What it does
+/// Checks for uses of `os.rename`.
+///
+/// ## Why is this bad?
+/// `pathlib` offers a high-level API for path manipulation, as compared to
+/// the lower-level API offered by `os`. When possible, using `Path` object
+/// methods such as `Path.rename()` can improve readability over the `os`
+/// module's counterparts (e.g., `os.rename()`).
+///
+/// ## Examples
+/// ```python
+/// import os
+///
+/// os.rename("old.py", "new.py")
+/// ```
+///
+/// Use instead:
+/// ```python
+/// from pathlib import Path
+///
+/// Path("old.py").rename("new.py")
+/// ```
+///
+/// ## Known issues
+/// While using `pathlib` can improve the readability and type safety of your code,
+/// it can be less performant than the lower-level alternatives that work directly with strings,
+/// especially on older versions of Python.
+///
+/// ## Fix Safety
+/// This rule's fix is marked as unsafe if the replacement would remove comments attached to the original expression.
+///
+/// ## References
+/// - [Python documentation: `Path.rename`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.rename)
+/// - [Python documentation: `os.rename`](https://docs.python.org/3/library/os.html#os.rename)
+/// - [PEP 428 – The pathlib module – object-oriented filesystem paths](https://peps.python.org/pep-0428/)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#correspondence-to-tools-in-the-os-module)
+/// - [Why you should be using pathlib](https://treyhunner.com/2018/12/why-you-should-be-using-pathlib/)
+/// - [No really, pathlib is great](https://treyhunner.com/2019/01/no-really-pathlib-is-great/)
+#[derive(ViolationMetadata)]
+pub(crate) struct OsRename;
+
+impl Violation for OsRename {
+    const FIX_AVAILABILITY: FixAvailability = FixAvailability::Sometimes;
+
+    #[derive_message_formats]
+    fn message(&self) -> String {
+        "`os.rename()` should be replaced by `Path.rename()`".to_string()
+    }
+
+    fn fix_title(&self) -> Option<String> {
+        Some("Replace with `Path(...).rename(...)`".to_string())
+    }
+}
+
+/// PTH104
+pub(crate) fn os_rename(checker: &Checker, call: &ExprCall, segments: &[&str]) {
+    if segments != ["os", "rename"] {
+        return;
+    }
+    // `src_dir_fd` and `dst_dir_fd` are not supported by pathlib, so check if they are
+    // set to non-default values.
+    // Signature as of Python 3.13 (https://docs.python.org/3/library/os.html#os.rename)
+    // ```text
+    //            0    1           2                  3
+    // os.rename(src, dst, *, src_dir_fd=None, dst_dir_fd=None)
+    // ```
+    if is_keyword_only_argument_non_default(&call.arguments, "src_dir_fd")
+        || is_keyword_only_argument_non_default(&call.arguments, "dst_dir_fd")
+    {
+        return;
+    }
+
+    check_os_pathlib_two_arg_calls(
+        checker,
+        call,
+        "rename",
+        "src",
+        "dst",
+        is_fix_os_rename_enabled(checker.settings()),
+        OsRename,
+    );
+}

crates/ruff_linter/src/rules/flake8_use_pathlib/rules/os_replace.rs

@@ -0,0 +1,94 @@
+use crate::checkers::ast::Checker;
+use crate::preview::is_fix_os_replace_enabled;
+use crate::rules::flake8_use_pathlib::helpers::{
+    check_os_pathlib_two_arg_calls, is_keyword_only_argument_non_default,
+};
+use crate::{FixAvailability, Violation};
+use ruff_macros::{ViolationMetadata, derive_message_formats};
+use ruff_python_ast::ExprCall;
+
+/// ## What it does
+/// Checks for uses of `os.replace`.
+///
+/// ## Why is this bad?
+/// `pathlib` offers a high-level API for path manipulation, as compared to
+/// the lower-level API offered by `os`. When possible, using `Path` object
+/// methods such as `Path.replace()` can improve readability over the `os`
+/// module's counterparts (e.g., `os.replace()`).
+///
+/// Note that `os` functions may be preferable if performance is a concern,
+/// e.g., in hot loops.
+///
+/// ## Examples
+/// ```python
+/// import os
+///
+/// os.replace("old.py", "new.py")
+/// ```
+///
+/// Use instead:
+/// ```python
+/// from pathlib import Path
+///
+/// Path("old.py").replace("new.py")
+/// ```
+///
+/// ## Known issues
+/// While using `pathlib` can improve the readability and type safety of your code,
+/// it can be less performant than the lower-level alternatives that work directly with strings,
+/// especially on older versions of Python.
+///
+/// ## Fix Safety
+/// This rule's fix is marked as unsafe if the replacement would remove comments attached to the original expression.
+///
+/// ## References
+/// - [Python documentation: `Path.replace`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.replace)
+/// - [Python documentation: `os.replace`](https://docs.python.org/3/library/os.html#os.replace)
+/// - [PEP 428 – The pathlib module – object-oriented filesystem paths](https://peps.python.org/pep-0428/)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#correspondence-to-tools-in-the-os-module)
+/// - [Why you should be using pathlib](https://treyhunner.com/2018/12/why-you-should-be-using-pathlib/)
+/// - [No really, pathlib is great](https://treyhunner.com/2019/01/no-really-pathlib-is-great/)
+#[derive(ViolationMetadata)]
+pub(crate) struct OsReplace;
+
+impl Violation for OsReplace {
+    const FIX_AVAILABILITY: FixAvailability = FixAvailability::Sometimes;
+
+    #[derive_message_formats]
+    fn message(&self) -> String {
+        "`os.replace()` should be replaced by `Path.replace()`".to_string()
+    }
+
+    fn fix_title(&self) -> Option<String> {
+        Some("Replace with `Path(...).replace(...)`".to_string())
+    }
+}
+
+/// PTH105
+pub(crate) fn os_replace(checker: &Checker, call: &ExprCall, segments: &[&str]) {
+    if segments != ["os", "replace"] {
+        return;
+    }
+    // `src_dir_fd` and `dst_dir_fd` are not supported by pathlib, so check if they are
+    // set to non-default values.
+    // Signature as of Python 3.13 (https://docs.python.org/3/library/os.html#os.replace)
+    // ```text
+    //             0    1           2                3
+    // os.replace(src, dst, *, src_dir_fd=None, dst_dir_fd=None)
+    // ```
+    if is_keyword_only_argument_non_default(&call.arguments, "src_dir_fd")
+        || is_keyword_only_argument_non_default(&call.arguments, "dst_dir_fd")
+    {
+        return;
+    }
+
+    check_os_pathlib_two_arg_calls(
+        checker,
+        call,
+        "replace",
+        "src",
+        "dst",
+        is_fix_os_replace_enabled(checker.settings()),
+        OsReplace,
+    );
+}

crates/ruff_linter/src/rules/flake8_use_pathlib/rules/replaceable_by_pathlib.rs

@@ -1,14 +1,16 @@
 use ruff_python_ast::{self as ast, Expr, ExprBooleanLiteral, ExprCall};
-use ruff_python_semantic::SemanticModel;
-use ruff_python_semantic::analyze::typing;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
-use crate::rules::flake8_use_pathlib::helpers::is_keyword_only_argument_non_default;
-use crate::rules::flake8_use_pathlib::rules::Glob;
-use crate::rules::flake8_use_pathlib::violations::{
-    BuiltinOpen, Joiner, OsChmod, OsListdir, OsMakedirs, OsMkdir, OsPathJoin, OsPathSamefile,
-    OsPathSplitext, OsRename, OsReplace, OsStat, OsSymlink, PyPath,
+use crate::rules::flake8_use_pathlib::helpers::{
+    is_file_descriptor, is_keyword_only_argument_non_default,
+};
+use crate::rules::flake8_use_pathlib::{
+    rules::Glob,
+    violations::{
+        BuiltinOpen, Joiner, OsListdir, OsMakedirs, OsMkdir, OsPathJoin, OsPathSplitext, OsStat,
+        OsSymlink, PyPath,
+    },
 };
 
 pub(crate) fn replaceable_by_pathlib(checker: &Checker, call: &ExprCall) {
@@ -18,24 +20,6 @@ pub(crate) fn replaceable_by_pathlib(checker: &Checker, call: &ExprCall) {
 
     let range = call.func.range();
     match qualified_name.segments() {
-        // PTH101
-        ["os", "chmod"] => {
-            // `dir_fd` is not supported by pathlib, so check if it's set to non-default values.
-            // Signature as of Python 3.13 (https://docs.python.org/3/library/os.html#os.chmod)
-            // ```text
-            //           0     1          2               3
-            // os.chmod(path, mode, *, dir_fd=None, follow_symlinks=True)
-            // ```
-            if call
-                .arguments
-                .find_argument_value("path", 0)
-                .is_some_and(|expr| is_file_descriptor(expr, checker.semantic()))
-                || is_keyword_only_argument_non_default(&call.arguments, "dir_fd")
-            {
-                return;
-            }
-            checker.report_diagnostic_if_enabled(OsChmod, range)
-        }
         // PTH102
         ["os", "makedirs"] => checker.report_diagnostic_if_enabled(OsMakedirs, range),
         // PTH103
@@ -51,38 +35,6 @@ pub(crate) fn replaceable_by_pathlib(checker: &Checker, call: &ExprCall) {
             }
             checker.report_diagnostic_if_enabled(OsMkdir, range)
         }
-        // PTH104
-        ["os", "rename"] => {
-            // `src_dir_fd` and `dst_dir_fd` are not supported by pathlib, so check if they are
-            // set to non-default values.
-            // Signature as of Python 3.13 (https://docs.python.org/3/library/os.html#os.rename)
-            // ```text
-            //           0    1       2                3
-            // os.rename(src, dst, *, src_dir_fd=None, dst_dir_fd=None)
-            // ```
-            if is_keyword_only_argument_non_default(&call.arguments, "src_dir_fd")
-                || is_keyword_only_argument_non_default(&call.arguments, "dst_dir_fd")
-            {
-                return;
-            }
-            checker.report_diagnostic_if_enabled(OsRename, range)
-        }
-        // PTH105
-        ["os", "replace"] => {
-            // `src_dir_fd` and `dst_dir_fd` are not supported by pathlib, so check if they are
-            // set to non-default values.
-            // Signature as of Python 3.13 (https://docs.python.org/3/library/os.html#os.replace)
-            // ```text
-            //              0    1       2                3
-            // os.replace(src, dst, *, src_dir_fd=None, dst_dir_fd=None)
-            // ```
-            if is_keyword_only_argument_non_default(&call.arguments, "src_dir_fd")
-                || is_keyword_only_argument_non_default(&call.arguments, "dst_dir_fd")
-            {
-                return;
-            }
-            checker.report_diagnostic_if_enabled(OsReplace, range)
-        }
         // PTH116
         ["os", "stat"] => {
             // `dir_fd` is not supported by pathlib, so check if it's set to non-default values.
@@ -124,8 +76,6 @@ pub(crate) fn replaceable_by_pathlib(checker: &Checker, call: &ExprCall) {
             },
             range,
         ),
-        // PTH121
-        ["os", "path", "samefile"] => checker.report_diagnostic_if_enabled(OsPathSamefile, range),
         // PTH122
         ["os", "path", "splitext"] => checker.report_diagnostic_if_enabled(OsPathSplitext, range),
         // PTH211
@@ -234,37 +184,6 @@ pub(crate) fn replaceable_by_pathlib(checker: &Checker, call: &ExprCall) {
     };
 }
 
-/// Returns `true` if the given expression looks like a file descriptor, i.e., if it is an integer.
-fn is_file_descriptor(expr: &Expr, semantic: &SemanticModel) -> bool {
-    if matches!(
-        expr,
-        Expr::NumberLiteral(ast::ExprNumberLiteral {
-            value: ast::Number::Int(_),
-            ..
-        })
-    ) {
-        return true;
-    }
-
-    let Some(name) = get_name_expr(expr) else {
-        return false;
-    };
-
-    let Some(binding) = semantic.only_binding(name).map(|id| semantic.binding(id)) else {
-        return false;
-    };
-
-    typing::is_int(binding, semantic)
-}
-
-fn get_name_expr(expr: &Expr) -> Option<&ast::ExprName> {
-    match expr {
-        Expr::Name(name) => Some(name),
-        Expr::Call(ExprCall { func, .. }) => get_name_expr(func),
-        _ => None,
-    }
-}
-
 /// Returns `true` if argument `name` is set to a non-default `None` value.
 fn is_argument_non_default(arguments: &ast::Arguments, name: &str, position: usize) -> bool {
     arguments

crates/ruff_linter/src/rules/flake8_use_pathlib/snapshots/ruff_linter__rules__flake8_use_pathlib__tests__full_name.py.snap

@@ -20,6 +20,7 @@ full_name.py:8:6: PTH101 `os.chmod()` should be replaced by `Path.chmod()`
  9 | aaa = os.mkdir(p)
 10 | os.makedirs(p)
    |
+   = help: Replace with `Path(...).chmod(...)`
 
 full_name.py:9:7: PTH102 `os.mkdir()` should be replaced by `Path.mkdir()`
    |
@@ -50,6 +51,7 @@ full_name.py:11:1: PTH104 `os.rename()` should be replaced by `Path.rename()`
 12 | os.replace(p)
 13 | os.rmdir(p)
    |
+   = help: Replace with `Path(...).rename(...)`
 
 full_name.py:12:1: PTH105 `os.replace()` should be replaced by `Path.replace()`
    |
@@ -60,6 +62,7 @@ full_name.py:12:1: PTH105 `os.replace()` should be replaced by `Path.replace()`
 13 | os.rmdir(p)
 14 | os.remove(p)
    |
+   = help: Replace with `Path(...).replace(...)`
 
 full_name.py:13:1: PTH106 `os.rmdir()` should be replaced by `Path.rmdir()`
    |
@@ -253,6 +256,7 @@ full_name.py:30:1: PTH121 `os.path.samefile()` should be replaced by `Path.samef
 31 | os.path.splitext(p)
 32 | with open(p) as fp:
    |
+   = help: Replace with `Path(...).samefile()`
 
 full_name.py:31:1: PTH122 `os.path.splitext()` should be replaced by `Path.suffix`, `Path.stem`, and `Path.parent`
    |

crates/ruff_linter/src/rules/flake8_use_pathlib/snapshots/ruff_linter__rules__flake8_use_pathlib__tests__import_as.py.snap

@@ -20,6 +20,7 @@ import_as.py:8:6: PTH101 `os.chmod()` should be replaced by `Path.chmod()`
  9 | aaa = foo.mkdir(p)
 10 | foo.makedirs(p)
    |
+   = help: Replace with `Path(...).chmod(...)`
 
 import_as.py:9:7: PTH102 `os.mkdir()` should be replaced by `Path.mkdir()`
    |
@@ -50,6 +51,7 @@ import_as.py:11:1: PTH104 `os.rename()` should be replaced by `Path.rename()`
 12 | foo.replace(p)
 13 | foo.rmdir(p)
    |
+   = help: Replace with `Path(...).rename(...)`
 
 import_as.py:12:1: PTH105 `os.replace()` should be replaced by `Path.replace()`
    |
@@ -60,6 +62,7 @@ import_as.py:12:1: PTH105 `os.replace()` should be replaced by `Path.replace()`
 13 | foo.rmdir(p)
 14 | foo.remove(p)
    |
+   = help: Replace with `Path(...).replace(...)`
 
 import_as.py:13:1: PTH106 `os.rmdir()` should be replaced by `Path.rmdir()`
    |
@@ -252,6 +255,7 @@ import_as.py:30:1: PTH121 `os.path.samefile()` should be replaced by `Path.samef
    | ^^^^^^^^^^^^^^ PTH121
 31 | foo_p.splitext(p)
    |
+   = help: Replace with `Path(...).samefile()`
 
 import_as.py:31:1: PTH122 `os.path.splitext()` should be replaced by `Path.suffix`, `Path.stem`, and `Path.parent`
    |

crates/ruff_linter/src/rules/flake8_use_pathlib/snapshots/ruff_linter__rules__flake8_use_pathlib__tests__import_from.py.snap

@@ -20,6 +20,7 @@ import_from.py:10:6: PTH101 `os.chmod()` should be replaced by `Path.chmod()`
 11 | aaa = mkdir(p)
 12 | makedirs(p)
    |
+   = help: Replace with `Path(...).chmod(...)`
 
 import_from.py:11:7: PTH102 `os.mkdir()` should be replaced by `Path.mkdir()`
    |
@@ -50,6 +51,7 @@ import_from.py:13:1: PTH104 `os.rename()` should be replaced by `Path.rename()`
 14 | replace(p)
 15 | rmdir(p)
    |
+   = help: Replace with `Path(...).rename(...)`
 
 import_from.py:14:1: PTH105 `os.replace()` should be replaced by `Path.replace()`
    |
@@ -60,6 +62,7 @@ import_from.py:14:1: PTH105 `os.replace()` should be replaced by `Path.replace()
 15 | rmdir(p)
 16 | remove(p)
    |
+   = help: Replace with `Path(...).replace(...)`
 
 import_from.py:15:1: PTH106 `os.rmdir()` should be replaced by `Path.rmdir()`
    |
@@ -253,6 +256,7 @@ import_from.py:32:1: PTH121 `os.path.samefile()` should be replaced by `Path.sam
 33 | splitext(p)
 34 | with open(p) as fp:
    |
+   = help: Replace with `Path(...).samefile()`
 
 import_from.py:33:1: PTH122 `os.path.splitext()` should be replaced by `Path.suffix`, `Path.stem`, and `Path.parent`
    |
@@ -289,3 +293,36 @@ import_from.py:43:10: PTH123 `open()` should be replaced by `Path.open()`
 43 |     with open(p) as _: ...  # Error
    |          ^^^^ PTH123
    |
+
+import_from.py:53:1: PTH104 `os.rename()` should be replaced by `Path.rename()`
+   |
+51 | file = "file_1.py"
+52 |
+53 | rename(file, "file_2.py")
+   | ^^^^^^ PTH104
+54 |
+55 | rename(
+   |
+   = help: Replace with `Path(...).rename(...)`
+
+import_from.py:55:1: PTH104 `os.rename()` should be replaced by `Path.rename()`
+   |
+53 | rename(file, "file_2.py")
+54 |
+55 | rename(
+   | ^^^^^^ PTH104
+56 |     # commment 1
+57 |     file, # comment 2
+   |
+   = help: Replace with `Path(...).rename(...)`
+
+import_from.py:63:1: PTH104 `os.rename()` should be replaced by `Path.rename()`
+   |
+61 | )
+62 |
+63 | rename(file, "file_2.py", src_dir_fd=None, dst_dir_fd=None)
+   | ^^^^^^ PTH104
+64 |
+65 | rename(file, "file_2.py", src_dir_fd=1)
+   |
+   = help: Replace with `Path(...).rename(...)`

crates/ruff_linter/src/rules/flake8_use_pathlib/snapshots/ruff_linter__rules__flake8_use_pathlib__tests__import_from_as.py.snap

@@ -20,6 +20,7 @@ import_from_as.py:15:6: PTH101 `os.chmod()` should be replaced by `Path.chmod()`
 16 | aaa = xmkdir(p)
 17 | xmakedirs(p)
    |
+   = help: Replace with `Path(...).chmod(...)`
 
 import_from_as.py:16:7: PTH102 `os.mkdir()` should be replaced by `Path.mkdir()`
    |
@@ -50,6 +51,7 @@ import_from_as.py:18:1: PTH104 `os.rename()` should be replaced by `Path.rename(
 19 | xreplace(p)
 20 | xrmdir(p)
    |
+   = help: Replace with `Path(...).rename(...)`
 
 import_from_as.py:19:1: PTH105 `os.replace()` should be replaced by `Path.replace()`
    |
@@ -60,6 +62,7 @@ import_from_as.py:19:1: PTH105 `os.replace()` should be replaced by `Path.replac
 20 | xrmdir(p)
 21 | xremove(p)
    |
+   = help: Replace with `Path(...).replace(...)`
 
 import_from_as.py:20:1: PTH106 `os.rmdir()` should be replaced by `Path.rmdir()`
    |
@@ -252,6 +255,7 @@ import_from_as.py:37:1: PTH121 `os.path.samefile()` should be replaced by `Path.
    | ^^^^^^^^^ PTH121
 38 | xsplitext(p)
    |
+   = help: Replace with `Path(...).samefile()`
 
 import_from_as.py:38:1: PTH122 `os.path.splitext()` should be replaced by `Path.suffix`, `Path.stem`, and `Path.parent`
    |

crates/ruff_linter/src/rules/flake8_use_pathlib/snapshots/ruff_linter__rules__flake8_use_pathlib__tests__preview_full_name.py.snap

@@ -34,6 +34,7 @@ full_name.py:8:6: PTH101 `os.chmod()` should be replaced by `Path.chmod()`
  9 | aaa = os.mkdir(p)
 10 | os.makedirs(p)
    |
+   = help: Replace with `Path(...).chmod(...)`
 
 full_name.py:9:7: PTH102 `os.mkdir()` should be replaced by `Path.mkdir()`
    |
@@ -64,6 +65,7 @@ full_name.py:11:1: PTH104 `os.rename()` should be replaced by `Path.rename()`
 12 | os.replace(p)
 13 | os.rmdir(p)
    |
+   = help: Replace with `Path(...).rename(...)`
 
 full_name.py:12:1: PTH105 `os.replace()` should be replaced by `Path.replace()`
    |
@@ -74,6 +76,7 @@ full_name.py:12:1: PTH105 `os.replace()` should be replaced by `Path.replace()`
 13 | os.rmdir(p)
 14 | os.remove(p)
    |
+   = help: Replace with `Path(...).replace(...)`
 
 full_name.py:13:1: PTH106 [*] `os.rmdir()` should be replaced by `Path.rmdir()`
    |
@@ -471,6 +474,7 @@ full_name.py:30:1: PTH121 `os.path.samefile()` should be replaced by `Path.samef
 31 | os.path.splitext(p)
 32 | with open(p) as fp:
    |
+   = help: Replace with `Path(...).samefile()`
 
 full_name.py:31:1: PTH122 `os.path.splitext()` should be replaced by `Path.suffix`, `Path.stem`, and `Path.parent`
    |

crates/ruff_linter/src/rules/flake8_use_pathlib/snapshots/ruff_linter__rules__flake8_use_pathlib__tests__preview_import_as.py.snap

@@ -34,6 +34,7 @@ import_as.py:8:6: PTH101 `os.chmod()` should be replaced by `Path.chmod()`
  9 | aaa = foo.mkdir(p)
 10 | foo.makedirs(p)
    |
+   = help: Replace with `Path(...).chmod(...)`
 
 import_as.py:9:7: PTH102 `os.mkdir()` should be replaced by `Path.mkdir()`
    |
@@ -64,6 +65,7 @@ import_as.py:11:1: PTH104 `os.rename()` should be replaced by `Path.rename()`
 12 | foo.replace(p)
 13 | foo.rmdir(p)
    |
+   = help: Replace with `Path(...).rename(...)`
 
 import_as.py:12:1: PTH105 `os.replace()` should be replaced by `Path.replace()`
    |
@@ -74,6 +76,7 @@ import_as.py:12:1: PTH105 `os.replace()` should be replaced by `Path.replace()`
 13 | foo.rmdir(p)
 14 | foo.remove(p)
    |
+   = help: Replace with `Path(...).replace(...)`
 
 import_as.py:13:1: PTH106 [*] `os.rmdir()` should be replaced by `Path.rmdir()`
    |
@@ -469,6 +472,7 @@ import_as.py:30:1: PTH121 `os.path.samefile()` should be replaced by `Path.samef
    | ^^^^^^^^^^^^^^ PTH121
 31 | foo_p.splitext(p)
    |
+   = help: Replace with `Path(...).samefile()`
 
 import_as.py:31:1: PTH122 `os.path.splitext()` should be replaced by `Path.suffix`, `Path.stem`, and `Path.parent`
    |

crates/ruff_linter/src/rules/flake8_use_pathlib/snapshots/ruff_linter__rules__flake8_use_pathlib__tests__preview_import_from.py.snap

@@ -35,6 +35,7 @@ import_from.py:10:6: PTH101 `os.chmod()` should be replaced by `Path.chmod()`
 11 | aaa = mkdir(p)
 12 | makedirs(p)
    |
+   = help: Replace with `Path(...).chmod(...)`
 
 import_from.py:11:7: PTH102 `os.mkdir()` should be replaced by `Path.mkdir()`
    |
@@ -65,6 +66,7 @@ import_from.py:13:1: PTH104 `os.rename()` should be replaced by `Path.rename()`
 14 | replace(p)
 15 | rmdir(p)
    |
+   = help: Replace with `Path(...).rename(...)`
 
 import_from.py:14:1: PTH105 `os.replace()` should be replaced by `Path.replace()`
    |
@@ -75,6 +77,7 @@ import_from.py:14:1: PTH105 `os.replace()` should be replaced by `Path.replace()
 15 | rmdir(p)
 16 | remove(p)
    |
+   = help: Replace with `Path(...).replace(...)`
 
 import_from.py:15:1: PTH106 [*] `os.rmdir()` should be replaced by `Path.rmdir()`
    |
@@ -484,6 +487,7 @@ import_from.py:32:1: PTH121 `os.path.samefile()` should be replaced by `Path.sam
 33 | splitext(p)
 34 | with open(p) as fp:
    |
+   = help: Replace with `Path(...).samefile()`
 
 import_from.py:33:1: PTH122 `os.path.splitext()` should be replaced by `Path.suffix`, `Path.stem`, and `Path.parent`
    |
@@ -520,3 +524,95 @@ import_from.py:43:10: PTH123 `open()` should be replaced by `Path.open()`
 43 |     with open(p) as _: ...  # Error
    |          ^^^^ PTH123
    |
+
+import_from.py:53:1: PTH104 [*] `os.rename()` should be replaced by `Path.rename()`
+   |
+51 | file = "file_1.py"
+52 |
+53 | rename(file, "file_2.py")
+   | ^^^^^^ PTH104
+54 |
+55 | rename(
+   |
+   = help: Replace with `Path(...).rename(...)`
+
+ℹ Safe fix
+2  2  | from os import remove, unlink, getcwd, readlink, stat
+3  3  | from os.path import abspath, exists, expanduser, isdir, isfile, islink
+4  4  | from os.path import isabs, join, basename, dirname, samefile, splitext
+   5  |+import pathlib
+5  6  | 
+6  7  | p = "/foo"
+7  8  | q = "bar"
+--------------------------------------------------------------------------------
+50 51 | 
+51 52 | file = "file_1.py"
+52 53 | 
+53    |-rename(file, "file_2.py")
+   54 |+pathlib.Path(file).rename("file_2.py")
+54 55 | 
+55 56 | rename(
+56 57 |     # commment 1
+
+import_from.py:55:1: PTH104 [*] `os.rename()` should be replaced by `Path.rename()`
+   |
+53 | rename(file, "file_2.py")
+54 |
+55 | rename(
+   | ^^^^^^ PTH104
+56 |     # commment 1
+57 |     file, # comment 2
+   |
+   = help: Replace with `Path(...).rename(...)`
+
+ℹ Unsafe fix
+2  2  | from os import remove, unlink, getcwd, readlink, stat
+3  3  | from os.path import abspath, exists, expanduser, isdir, isfile, islink
+4  4  | from os.path import isabs, join, basename, dirname, samefile, splitext
+   5  |+import pathlib
+5  6  | 
+6  7  | p = "/foo"
+7  8  | q = "bar"
+--------------------------------------------------------------------------------
+52 53 | 
+53 54 | rename(file, "file_2.py")
+54 55 | 
+55    |-rename(
+56    |-    # commment 1
+57    |-    file, # comment 2
+58    |-    "file_2.py"
+59    |-    ,
+60    |-    # comment 3
+61    |-)
+   56 |+pathlib.Path(file).rename("file_2.py")
+62 57 | 
+63 58 | rename(file, "file_2.py", src_dir_fd=None, dst_dir_fd=None)
+64 59 | 
+
+import_from.py:63:1: PTH104 [*] `os.rename()` should be replaced by `Path.rename()`
+   |
+61 | )
+62 |
+63 | rename(file, "file_2.py", src_dir_fd=None, dst_dir_fd=None)
+   | ^^^^^^ PTH104
+64 |
+65 | rename(file, "file_2.py", src_dir_fd=1)
+   |
+   = help: Replace with `Path(...).rename(...)`
+
+ℹ Safe fix
+2  2  | from os import remove, unlink, getcwd, readlink, stat
+3  3  | from os.path import abspath, exists, expanduser, isdir, isfile, islink
+4  4  | from os.path import isabs, join, basename, dirname, samefile, splitext
+   5  |+import pathlib
+5  6  | 
+6  7  | p = "/foo"
+7  8  | q = "bar"
+--------------------------------------------------------------------------------
+60 61 |     # comment 3
+61 62 | )
+62 63 | 
+63    |-rename(file, "file_2.py", src_dir_fd=None, dst_dir_fd=None)
+   64 |+pathlib.Path(file).rename("file_2.py")
+64 65 | 
+65 66 | rename(file, "file_2.py", src_dir_fd=1)

crates/ruff_linter/src/rules/flake8_use_pathlib/snapshots/ruff_linter__rules__flake8_use_pathlib__tests__preview_import_from_as.py.snap

@@ -35,6 +35,7 @@ import_from_as.py:15:6: PTH101 `os.chmod()` should be replaced by `Path.chmod()`
 16 | aaa = xmkdir(p)
 17 | xmakedirs(p)
    |
+   = help: Replace with `Path(...).chmod(...)`
 
 import_from_as.py:16:7: PTH102 `os.mkdir()` should be replaced by `Path.mkdir()`
    |
@@ -65,6 +66,7 @@ import_from_as.py:18:1: PTH104 `os.rename()` should be replaced by `Path.rename(
 19 | xreplace(p)
 20 | xrmdir(p)
    |
+   = help: Replace with `Path(...).rename(...)`
 
 import_from_as.py:19:1: PTH105 `os.replace()` should be replaced by `Path.replace()`
    |
@@ -75,6 +77,7 @@ import_from_as.py:19:1: PTH105 `os.replace()` should be replaced by `Path.replac
 20 | xrmdir(p)
 21 | xremove(p)
    |
+   = help: Replace with `Path(...).replace(...)`
 
 import_from_as.py:20:1: PTH106 [*] `os.rmdir()` should be replaced by `Path.rmdir()`
    |
@@ -482,6 +485,7 @@ import_from_as.py:37:1: PTH121 `os.path.samefile()` should be replaced by `Path.
    | ^^^^^^^^^ PTH121
 38 | xsplitext(p)
    |
+   = help: Replace with `Path(...).samefile()`
 
 import_from_as.py:38:1: PTH122 `os.path.splitext()` should be replaced by `Path.suffix`, `Path.stem`, and `Path.parent`
    |

crates/ruff_linter/src/rules/flake8_use_pathlib/violations.rs

@@ -2,51 +2,6 @@ use ruff_macros::{ViolationMetadata, derive_message_formats};
 
 use crate::Violation;
 
-/// ## What it does
-/// Checks for uses of `os.chmod`.
-///
-/// ## Why is this bad?
-/// `pathlib` offers a high-level API for path manipulation, as compared to
-/// the lower-level API offered by `os`. When possible, using `Path` object
-/// methods such as `Path.chmod()` can improve readability over the `os`
-/// module's counterparts (e.g., `os.chmod()`).
-///
-/// ## Examples
-/// ```python
-/// import os
-///
-/// os.chmod("file.py", 0o444)
-/// ```
-///
-/// Use instead:
-/// ```python
-/// from pathlib import Path
-///
-/// Path("file.py").chmod(0o444)
-/// ```
-///
-/// ## Known issues
-/// While using `pathlib` can improve the readability and type safety of your code,
-/// it can be less performant than the lower-level alternatives that work directly with strings,
-/// especially on older versions of Python.
-///
-/// ## References
-/// - [Python documentation: `Path.chmod`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.chmod)
-/// - [Python documentation: `os.chmod`](https://docs.python.org/3/library/os.html#os.chmod)
-/// - [PEP 428 – The pathlib module – object-oriented filesystem paths](https://peps.python.org/pep-0428/)
-/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#correspondence-to-tools-in-the-os-module)
-/// - [Why you should be using pathlib](https://treyhunner.com/2018/12/why-you-should-be-using-pathlib/)
-/// - [No really, pathlib is great](https://treyhunner.com/2019/01/no-really-pathlib-is-great/)
-#[derive(ViolationMetadata)]
-pub(crate) struct OsChmod;
-
-impl Violation for OsChmod {
-    #[derive_message_formats]
-    fn message(&self) -> String {
-        "`os.chmod()` should be replaced by `Path.chmod()`".to_string()
-    }
-}
-
 /// ## What it does
 /// Checks for uses of `os.makedirs`.
 ///
@@ -137,99 +92,6 @@ impl Violation for OsMkdir {
     }
 }
 
-/// ## What it does
-/// Checks for uses of `os.rename`.
-///
-/// ## Why is this bad?
-/// `pathlib` offers a high-level API for path manipulation, as compared to
-/// the lower-level API offered by `os`. When possible, using `Path` object
-/// methods such as `Path.rename()` can improve readability over the `os`
-/// module's counterparts (e.g., `os.rename()`).
-///
-/// ## Examples
-/// ```python
-/// import os
-///
-/// os.rename("old.py", "new.py")
-/// ```
-///
-/// Use instead:
-/// ```python
-/// from pathlib import Path
-///
-/// Path("old.py").rename("new.py")
-/// ```
-///
-/// ## Known issues
-/// While using `pathlib` can improve the readability and type safety of your code,
-/// it can be less performant than the lower-level alternatives that work directly with strings,
-/// especially on older versions of Python.
-///
-/// ## References
-/// - [Python documentation: `Path.rename`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.rename)
-/// - [Python documentation: `os.rename`](https://docs.python.org/3/library/os.html#os.rename)
-/// - [PEP 428 – The pathlib module – object-oriented filesystem paths](https://peps.python.org/pep-0428/)
-/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#correspondence-to-tools-in-the-os-module)
-/// - [Why you should be using pathlib](https://treyhunner.com/2018/12/why-you-should-be-using-pathlib/)
-/// - [No really, pathlib is great](https://treyhunner.com/2019/01/no-really-pathlib-is-great/)
-#[derive(ViolationMetadata)]
-pub(crate) struct OsRename;
-
-impl Violation for OsRename {
-    #[derive_message_formats]
-    fn message(&self) -> String {
-        "`os.rename()` should be replaced by `Path.rename()`".to_string()
-    }
-}
-
-/// ## What it does
-/// Checks for uses of `os.replace`.
-///
-/// ## Why is this bad?
-/// `pathlib` offers a high-level API for path manipulation, as compared to
-/// the lower-level API offered by `os`. When possible, using `Path` object
-/// methods such as `Path.replace()` can improve readability over the `os`
-/// module's counterparts (e.g., `os.replace()`).
-///
-/// Note that `os` functions may be preferable if performance is a concern,
-/// e.g., in hot loops.
-///
-/// ## Examples
-/// ```python
-/// import os
-///
-/// os.replace("old.py", "new.py")
-/// ```
-///
-/// Use instead:
-/// ```python
-/// from pathlib import Path
-///
-/// Path("old.py").replace("new.py")
-/// ```
-///
-/// ## Known issues
-/// While using `pathlib` can improve the readability and type safety of your code,
-/// it can be less performant than the lower-level alternatives that work directly with strings,
-/// especially on older versions of Python.
-///
-/// ## References
-/// - [Python documentation: `Path.replace`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.replace)
-/// - [Python documentation: `os.replace`](https://docs.python.org/3/library/os.html#os.replace)
-/// - [PEP 428 – The pathlib module – object-oriented filesystem paths](https://peps.python.org/pep-0428/)
-/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#correspondence-to-tools-in-the-os-module)
-/// - [Why you should be using pathlib](https://treyhunner.com/2018/12/why-you-should-be-using-pathlib/)
-/// - [No really, pathlib is great](https://treyhunner.com/2019/01/no-really-pathlib-is-great/)
-#[derive(ViolationMetadata)]
-pub(crate) struct OsReplace;
-
-impl Violation for OsReplace {
-    #[derive_message_formats]
-    fn message(&self) -> String {
-        "`os.replace()` should be replaced by `Path.replace()`".to_string()
-    }
-}
-
 /// ## What it does
 /// Checks for uses of `os.stat`.
 ///
@@ -347,51 +209,6 @@ pub(crate) enum Joiner {
     Joinpath,
 }
 
-/// ## What it does
-/// Checks for uses of `os.path.samefile`.
-///
-/// ## Why is this bad?
-/// `pathlib` offers a high-level API for path manipulation, as compared to
-/// the lower-level API offered by `os.path`. When possible, using `Path` object
-/// methods such as `Path.samefile()` can improve readability over the `os.path`
-/// module's counterparts (e.g., `os.path.samefile()`).
-///
-/// ## Examples
-/// ```python
-/// import os
-///
-/// os.path.samefile("f1.py", "f2.py")
-/// ```
-///
-/// Use instead:
-/// ```python
-/// from pathlib import Path
-///
-/// Path("f1.py").samefile("f2.py")
-/// ```
-///
-/// ## Known issues
-/// While using `pathlib` can improve the readability and type safety of your code,
-/// it can be less performant than the lower-level alternatives that work directly with strings,
-/// especially on older versions of Python.
-///
-/// ## References
-/// - [Python documentation: `Path.samefile`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.samefile)
-/// - [Python documentation: `os.path.samefile`](https://docs.python.org/3/library/os.path.html#os.path.samefile)
-/// - [PEP 428 – The pathlib module – object-oriented filesystem paths](https://peps.python.org/pep-0428/)
-/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#correspondence-to-tools-in-the-os-module)
-/// - [Why you should be using pathlib](https://treyhunner.com/2018/12/why-you-should-be-using-pathlib/)
-/// - [No really, pathlib is great](https://treyhunner.com/2019/01/no-really-pathlib-is-great/)
-#[derive(ViolationMetadata)]
-pub(crate) struct OsPathSamefile;
-
-impl Violation for OsPathSamefile {
-    #[derive_message_formats]
-    fn message(&self) -> String {
-        "`os.path.samefile()` should be replaced by `Path.samefile()`".to_string()
-    }
-}
-
 /// ## What it does
 /// Checks for uses of `os.path.splitext`.
 ///

crates/ruff_linter/src/rules/pep8_naming/rules/invalid_function_name.rs

@@ -100,7 +100,7 @@ pub(crate) fn invalid_function_name(
         return;
     }
 
-    // Ignore the do_* methods of the http.server.BaseHTTPRequestHandler class
+    // Ignore the do_* methods of the http.server.BaseHTTPRequestHandler class and its subclasses
     if name.starts_with("do_")
         && parent_class.is_some_and(|class| {
             any_base_class(class, semantic, &mut |superclass| {
@@ -108,7 +108,13 @@ pub(crate) fn invalid_function_name(
                 qualified.is_some_and(|name| {
                     matches!(
                         name.segments(),
-                        ["http", "server", "BaseHTTPRequestHandler"]
+                        [
+                            "http",
+                            "server",
+                            "BaseHTTPRequestHandler"
+                                | "CGIHTTPRequestHandler"
+                                | "SimpleHTTPRequestHandler"
+                        ]
                     )
                 })
             })

crates/ruff_linter/src/rules/pep8_naming/snapshots/ruff_linter__rules__pep8_naming__tests__N802_N802.py.snap

@@ -55,3 +55,21 @@ N802.py:84:9: N802 Function name `dont_GET` should be lowercase
    |         ^^^^^^^^ N802
 85 |         pass
    |
+
+N802.py:95:9: N802 Function name `dont_OPTIONS` should be lowercase
+   |
+93 |         pass
+94 |
+95 |     def dont_OPTIONS(self):
+   |         ^^^^^^^^^^^^ N802
+96 |         pass
+   |
+
+N802.py:106:9: N802 Function name `dont_OPTIONS` should be lowercase
+    |
+104 |         pass
+105 |
+106 |     def dont_OPTIONS(self):
+    |         ^^^^^^^^^^^^ N802
+107 |         pass
+    |

crates/ruff_linter/src/rules/perflint/rules/manual_list_comprehension.rs

@@ -406,7 +406,14 @@ fn convert_to_list_extend(
     };
     let target_str = locator.slice(for_stmt.target.range());
     let elt_str = locator.slice(to_append);
-    let generator_str = format!("{elt_str} {for_type} {target_str} in {for_iter_str}{if_str}");
+    let generator_str = if to_append
+        .as_generator_expr()
+        .is_some_and(|generator| !generator.parenthesized)
+    {
+        format!("({elt_str}) {for_type} {target_str} in {for_iter_str}{if_str}")
+    } else {
+        format!("{elt_str} {for_type} {target_str} in {for_iter_str}{if_str}")
+    };
 
     let variable_name = locator.slice(binding);
     let for_loop_inline_comments = comment_strings_in_range(

crates/ruff_linter/src/rules/perflint/snapshots/ruff_linter__rules__perflint__tests__PERF401_PERF401.py.snap

@@ -241,5 +241,27 @@ PERF401.py:280:13: PERF401 Use `list.extend` to create a transformed list
 279 |         if lambda: 0:
 280 |             dst.append(i)
     |             ^^^^^^^^^^^^^ PERF401
+281 |
+282 | def f():
     |
     = help: Replace for loop with list.extend
+
+PERF401.py:286:9: PERF401 Use a list comprehension to create a transformed list
+    |
+284 |     result = []
+285 |     for i in range(3):
+286 |         result.append(x for x in [i])
+    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ PERF401
+287 |
+288 | def f():
+    |
+    = help: Replace for loop with list comprehension
+
+PERF401.py:292:9: PERF401 Use a list comprehension to create a transformed list
+    |
+290 |     result = []
+291 |     for i in range(3):
+292 |         result.append((x for x in [i]))
+    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ PERF401
+    |
+    = help: Replace for loop with list comprehension

crates/ruff_linter/src/rules/perflint/snapshots/ruff_linter__rules__perflint__tests__preview__PERF401_PERF401.py.snap

@@ -566,6 +566,8 @@ PERF401.py:280:13: PERF401 [*] Use `list.extend` to create a transformed list
 279 |         if lambda: 0:
 280 |             dst.append(i)
     |             ^^^^^^^^^^^^^ PERF401
+281 |
+282 | def f():
     |
     = help: Replace for loop with list.extend
 
@@ -577,3 +579,47 @@ PERF401.py:280:13: PERF401 [*] Use `list.extend` to create a transformed list
 279     |-        if lambda: 0:
 280     |-            dst.append(i)
     278 |+    dst.extend(i for i in src if (lambda: 0))
+281 279 | 
+282 280 | def f():
+283 281 |     i = "xyz"
+
+PERF401.py:286:9: PERF401 [*] Use a list comprehension to create a transformed list
+    |
+284 |     result = []
+285 |     for i in range(3):
+286 |         result.append(x for x in [i])
+    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ PERF401
+287 |
+288 | def f():
+    |
+    = help: Replace for loop with list comprehension
+
+ℹ Unsafe fix
+281 281 | 
+282 282 | def f():
+283 283 |     i = "xyz"
+284     |-    result = []
+285     |-    for i in range(3):
+286     |-        result.append(x for x in [i])
+    284 |+    result = [(x for x in [i]) for i in range(3)]
+287 285 | 
+288 286 | def f():
+289 287 |     i = "xyz"
+
+PERF401.py:292:9: PERF401 [*] Use a list comprehension to create a transformed list
+    |
+290 |     result = []
+291 |     for i in range(3):
+292 |         result.append((x for x in [i]))
+    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ PERF401
+    |
+    = help: Replace for loop with list comprehension
+
+ℹ Unsafe fix
+287 287 | 
+288 288 | def f():
+289 289 |     i = "xyz"
+290     |-    result = []
+291     |-    for i in range(3):
+292     |-        result.append((x for x in [i]))
+    290 |+    result = [(x for x in [i]) for i in range(3)]

crates/ruff_linter/src/rules/pylint/mod.rs

@@ -48,6 +48,7 @@ mod tests {
     #[test_case(Rule::ComparisonWithItself, Path::new("comparison_with_itself.py"))]
     #[test_case(Rule::EqWithoutHash, Path::new("eq_without_hash.py"))]
     #[test_case(Rule::EmptyComment, Path::new("empty_comment.py"))]
+    #[test_case(Rule::EmptyComment, Path::new("empty_comment_line_continuation.py"))]
     #[test_case(Rule::ManualFromImport, Path::new("import_aliasing.py"))]
     #[test_case(Rule::IfStmtMinMax, Path::new("if_stmt_min_max.py"))]
     #[test_case(Rule::SingleStringSlots, Path::new("single_string_slots.py"))]

crates/ruff_linter/src/rules/pylint/rules/empty_comment.rs

@@ -1,4 +1,5 @@
 use ruff_macros::{ViolationMetadata, derive_message_formats};
+use ruff_python_index::Indexer;
 use ruff_python_trivia::{CommentRanges, is_python_whitespace};
 use ruff_source_file::LineRanges;
 use ruff_text_size::{TextRange, TextSize};
@@ -49,6 +50,7 @@ pub(crate) fn empty_comments(
     context: &LintContext,
     comment_ranges: &CommentRanges,
     locator: &Locator,
+    indexer: &Indexer,
 ) {
     let block_comments = comment_ranges.block_comments(locator.contents());
 
@@ -59,12 +61,12 @@ pub(crate) fn empty_comments(
         }
 
         // If the line contains an empty comment, add a diagnostic.
-        empty_comment(context, range, locator);
+        empty_comment(context, range, locator, indexer);
     }
 }
 
 /// Return a [`Diagnostic`] if the comment at the given [`TextRange`] is empty.
-fn empty_comment(context: &LintContext, range: TextRange, locator: &Locator) {
+fn empty_comment(context: &LintContext, range: TextRange, locator: &Locator, indexer: &Indexer) {
     // Check: is the comment empty?
     if !locator
         .slice(range)
@@ -95,12 +97,20 @@ fn empty_comment(context: &LintContext, range: TextRange, locator: &Locator) {
             }
         });
 
+    // If there is no character preceding the comment, this comment must be on its own physical line.
+    // If there is a line preceding the empty comment's line, check if it ends in a line continuation character. (`\`)
+    let is_on_same_logical_line = indexer
+        .preceded_by_continuations(first_hash_col, locator.contents())
+        .is_some();
+
     if let Some(mut diagnostic) = context
         .report_diagnostic_if_enabled(EmptyComment, TextRange::new(first_hash_col, line.end()))
     {
         diagnostic.set_fix(Fix::safe_edit(
             if let Some(deletion_start_col) = deletion_start_col {
                 Edit::deletion(line.start() + deletion_start_col, line.end())
+            } else if is_on_same_logical_line {
+                Edit::deletion(first_hash_col, line.end())
             } else {
                 Edit::range_deletion(locator.full_line_range(first_hash_col))
             },

crates/ruff_linter/src/rules/pylint/snapshots/ruff_linter__rules__pylint__tests__PLR2044_empty_comment_line_continuation.py.snap

@@ -0,0 +1,36 @@
+---
+source: crates/ruff_linter/src/rules/pylint/mod.rs
+---
+empty_comment_line_continuation.py:1:1: PLR2044 [*] Line with empty comment
+  |
+1 | #
+  | ^ PLR2044
+2 | x = 0 \
+3 | #
+  |
+  = help: Delete the empty comment
+
+ℹ Safe fix
+1   |-#
+2 1 | x = 0 \
+3 2 | #
+4 3 | +1
+
+empty_comment_line_continuation.py:3:1: PLR2044 [*] Line with empty comment
+  |
+1 | #
+2 | x = 0 \
+3 | #
+  | ^ PLR2044
+4 | +1
+5 | print(x)
+  |
+  = help: Delete the empty comment
+
+ℹ Safe fix
+1 1 | #
+2 2 | x = 0 \
+3   |-#
+  3 |+
+4 4 | +1
+5 5 | print(x)

crates/ruff_linter/src/rules/ruff/mod.rs

@@ -534,6 +534,7 @@ mod tests {
     #[test_case(Rule::UnnecessaryRegularExpression, Path::new("RUF055_0.py"))]
     #[test_case(Rule::UnnecessaryRegularExpression, Path::new("RUF055_1.py"))]
     #[test_case(Rule::UnnecessaryRegularExpression, Path::new("RUF055_2.py"))]
+    #[test_case(Rule::UnnecessaryRegularExpression, Path::new("RUF055_3.py"))]
     #[test_case(Rule::PytestRaisesAmbiguousPattern, Path::new("RUF043.py"))]
     #[test_case(Rule::IndentedFormFeed, Path::new("RUF054.py"))]
     #[test_case(Rule::ImplicitClassVarInDataclass, Path::new("RUF045.py"))]

crates/ruff_linter/src/rules/ruff/rules/unnecessary_regular_expression.rs

@@ -1,8 +1,8 @@
 use itertools::Itertools;
 use ruff_macros::{ViolationMetadata, derive_message_formats};
 use ruff_python_ast::{
-    Arguments, CmpOp, Expr, ExprAttribute, ExprCall, ExprCompare, ExprContext, ExprStringLiteral,
-    ExprUnaryOp, Identifier, UnaryOp,
+    Arguments, CmpOp, Expr, ExprAttribute, ExprBytesLiteral, ExprCall, ExprCompare, ExprContext,
+    ExprStringLiteral, ExprUnaryOp, Identifier, UnaryOp,
 };
 use ruff_python_semantic::analyze::typing::find_binding_value;
 use ruff_python_semantic::{Modules, SemanticModel};
@@ -72,6 +72,9 @@ impl Violation for UnnecessaryRegularExpression {
     }
 }
 
+const METACHARACTERS: [char; 12] = ['.', '^', '$', '*', '+', '?', '{', '[', '\\', '|', '(', ')'];
+const ESCAPABLE_SINGLE_CHARACTERS: &str = "abfnrtv";
+
 /// RUF055
 pub(crate) fn unnecessary_regular_expression(checker: &Checker, call: &ExprCall) {
     // adapted from unraw_re_pattern
@@ -96,16 +99,19 @@ pub(crate) fn unnecessary_regular_expression(checker: &Checker, call: &ExprCall)
     };
 
     // For now, restrict this rule to string literals and variables that can be resolved to literals
-    let Some(string_lit) = resolve_string_literal(re_func.pattern, semantic) else {
+    let Some(literal) = resolve_literal(re_func.pattern, semantic) else {
         return;
     };
 
     // For now, reject any regex metacharacters. Compare to the complete list
     // from https://docs.python.org/3/howto/regex.html#matching-characters
-    let has_metacharacters = string_lit
-        .value
-        .to_str()
-        .contains(['.', '^', '$', '*', '+', '?', '{', '[', '\\', '|', '(', ')']);
+    let has_metacharacters = match &literal {
+        Literal::Str(str_lit) => str_lit.value.to_str().contains(METACHARACTERS),
+        Literal::Bytes(bytes_lit) => bytes_lit
+            .value
+            .iter()
+            .any(|part| part.iter().any(|&b| METACHARACTERS.contains(&(b as char)))),
+    };
 
     if has_metacharacters {
         return;
@@ -186,28 +192,48 @@ impl<'a> ReFunc<'a> {
             // version
             ("sub", 3) => {
                 let repl = call.arguments.find_argument_value("repl", 1)?;
-                let lit = resolve_string_literal(repl, semantic)?;
+                let lit = resolve_literal(repl, semantic)?;
                 let mut fixable = true;
-                for (c, next) in lit.value.chars().tuple_windows() {
-                    // `\0` (or any other ASCII digit) and `\g` have special meaning in `repl` strings.
-                    // Meanwhile, nearly all other escapes of ASCII letters in a `repl` string causes
-                    // `re.PatternError` to be raised at runtime.
-                    //
-                    // If we see that the escaped character is an alphanumeric ASCII character,
-                    // we should only emit a diagnostic suggesting to replace the `re.sub()` call with
-                    // `str.replace`if we can detect that the escaped character is one that is both
-                    // valid in a `repl` string *and* does not have any special meaning in a REPL string.
-                    //
-                    // It's out of scope for this rule to change invalid `re.sub()` calls into something
-                    // that would not raise an exception at runtime. They should be left as-is.
-                    if c == '\\' && next.is_ascii_alphanumeric() {
-                        if "abfnrtv".contains(next) {
-                            fixable = false;
-                        } else {
-                            return None;
+
+                match lit {
+                    Literal::Str(lit_str) => {
+                        // Perform escape analysis for replacement literals.
+                        for (c, next) in lit_str.value.to_str().chars().tuple_windows() {
+                            // `\\0` (or any other ASCII digit) and `\\g` have special meaning in `repl` strings.
+                            // Meanwhile, nearly all other escapes of ASCII letters in a `repl` string causes
+                            // `re.PatternError` to be raised at runtime.
+                            //
+                            // If we see that the escaped character is an alphanumeric ASCII character,
+                            // we should only emit a diagnostic suggesting to replace the `re.sub()` call with
+                            // `str.replace`if we can detect that the escaped character is one that is both
+                            // valid in a `repl` string *and* does not have any special meaning in a REPL string.
+                            //
+                            // It's out of scope for this rule to change invalid `re.sub()` calls into something
+                            // that would not raise an exception at runtime. They should be left as-is.
+                            if c == '\\' && next.is_ascii_alphanumeric() {
+                                if ESCAPABLE_SINGLE_CHARACTERS.contains(next) {
+                                    fixable = false;
+                                } else {
+                                    return None;
+                                }
+                            }
+                        }
+                    }
+                    Literal::Bytes(lit_bytes) => {
+                        for part in &lit_bytes.value {
+                            for (byte, next) in part.iter().copied().tuple_windows() {
+                                if byte == b'\\' && (next as char).is_ascii_alphanumeric() {
+                                    if ESCAPABLE_SINGLE_CHARACTERS.contains(next as char) {
+                                        fixable = false;
+                                    } else {
+                                        return None;
+                                    }
+                                }
+                            }
                         }
                     }
                 }
+
                 Some(ReFunc {
                     kind: ReFuncKind::Sub {
                         repl: fixable.then_some(repl),
@@ -329,6 +355,43 @@ impl<'a> ReFunc<'a> {
     }
 }
 
+/// A literal that can be either a string or a bytes literal.
+enum Literal<'a> {
+    Str(&'a ExprStringLiteral),
+    Bytes(&'a ExprBytesLiteral),
+}
+
+/// Try to resolve `name` to either a string or bytes literal in `semantic`.
+fn resolve_literal<'a>(name: &'a Expr, semantic: &'a SemanticModel) -> Option<Literal<'a>> {
+    if let Some(str_lit) = resolve_string_literal(name, semantic) {
+        return Some(Literal::Str(str_lit));
+    }
+    if let Some(bytes_lit) = resolve_bytes_literal(name, semantic) {
+        return Some(Literal::Bytes(bytes_lit));
+    }
+    None
+}
+
+/// Try to resolve `name` to an [`ExprBytesLiteral`] in `semantic`.
+fn resolve_bytes_literal<'a>(
+    name: &'a Expr,
+    semantic: &'a SemanticModel,
+) -> Option<&'a ExprBytesLiteral> {
+    if name.is_bytes_literal_expr() {
+        return name.as_bytes_literal_expr();
+    }
+
+    if let Some(name_expr) = name.as_name_expr() {
+        let binding = semantic.binding(semantic.only_binding(name_expr)?);
+        let value = find_binding_value(binding, semantic)?;
+        if value.is_bytes_literal_expr() {
+            return value.as_bytes_literal_expr();
+        }
+    }
+
+    None
+}
+
 /// Try to resolve `name` to an [`ExprStringLiteral`] in `semantic`.
 fn resolve_string_literal<'a>(
     name: &'a Expr,

crates/ruff_linter/src/rules/ruff/snapshots/ruff_linter__rules__ruff__tests__preview__RUF055_RUF055_3.py.snap

@@ -0,0 +1,80 @@
+---
+source: crates/ruff_linter/src/rules/ruff/mod.rs
+---
+RUF055_3.py:6:1: RUF055 [*] Plain string pattern passed to `re` function
+  |
+5 | # Should be replaced with `b_src.replace(rb"x", b"y")`
+6 | re.sub(rb"x", b"y", b_src)
+  | ^^^^^^^^^^^^^^^^^^^^^^^^^^ RUF055
+7 |
+8 | # Should be replaced with `b_src.startswith(rb"abc")`
+  |
+  = help: Replace with `b_src.replace(rb"x", b"y")`
+
+ℹ Safe fix
+3 3 | b_src = b"abc"
+4 4 | 
+5 5 | # Should be replaced with `b_src.replace(rb"x", b"y")`
+6   |-re.sub(rb"x", b"y", b_src)
+  6 |+b_src.replace(rb"x", b"y")
+7 7 | 
+8 8 | # Should be replaced with `b_src.startswith(rb"abc")`
+9 9 | if re.match(rb"abc", b_src):
+
+RUF055_3.py:9:4: RUF055 [*] Plain string pattern passed to `re` function
+   |
+ 8 | # Should be replaced with `b_src.startswith(rb"abc")`
+ 9 | if re.match(rb"abc", b_src):
+   |    ^^^^^^^^^^^^^^^^^^^^^^^^ RUF055
+10 |     pass
+   |
+   = help: Replace with `b_src.startswith(rb"abc")`
+
+ℹ Safe fix
+6  6  | re.sub(rb"x", b"y", b_src)
+7  7  | 
+8  8  | # Should be replaced with `b_src.startswith(rb"abc")`
+9     |-if re.match(rb"abc", b_src):
+   9  |+if b_src.startswith(rb"abc"):
+10 10 |     pass
+11 11 | 
+12 12 | # Should be replaced with `rb"x" in b_src`
+
+RUF055_3.py:13:4: RUF055 [*] Plain string pattern passed to `re` function
+   |
+12 | # Should be replaced with `rb"x" in b_src`
+13 | if re.search(rb"x", b_src):
+   |    ^^^^^^^^^^^^^^^^^^^^^^^ RUF055
+14 |     pass
+   |
+   = help: Replace with `rb"x" in b_src`
+
+ℹ Safe fix
+10 10 |     pass
+11 11 | 
+12 12 | # Should be replaced with `rb"x" in b_src`
+13    |-if re.search(rb"x", b_src):
+   13 |+if rb"x" in b_src:
+14 14 |     pass
+15 15 | 
+16 16 | # Should be replaced with `b_src.split(rb"abc")`
+
+RUF055_3.py:17:1: RUF055 [*] Plain string pattern passed to `re` function
+   |
+16 | # Should be replaced with `b_src.split(rb"abc")`
+17 | re.split(rb"abc", b_src)
+   | ^^^^^^^^^^^^^^^^^^^^^^^^ RUF055
+18 |
+19 | # Patterns containing metacharacters should NOT be replaced
+   |
+   = help: Replace with `b_src.split(rb"abc")`
+
+ℹ Safe fix
+14 14 |     pass
+15 15 | 
+16 16 | # Should be replaced with `b_src.split(rb"abc")`
+17    |-re.split(rb"abc", b_src)
+   17 |+b_src.split(rb"abc")
+18 18 | 
+19 19 | # Patterns containing metacharacters should NOT be replaced
+20 20 | re.sub(rb"ab[c]", b"", b_src)

crates/ruff_linter/src/test.rs

@@ -272,7 +272,7 @@ Either ensure you always emit a fix or change `Violation::FIX_AVAILABILITY` to e
             }
 
             assert!(
-                !(fixable && diagnostic.suggestion().is_none()),
+                !(fixable && diagnostic.first_help_text().is_none()),
                 "Diagnostic emitted by {rule:?} is fixable but \
                 `Violation::fix_title` returns `None`"
             );

crates/ruff_python_ast/src/visitor/source_order.rs

@@ -235,12 +235,7 @@ impl TraversalSignal {
 }
 
 pub fn walk_annotation<'a, V: SourceOrderVisitor<'a> + ?Sized>(visitor: &mut V, expr: &'a Expr) {
-    let node = AnyNodeRef::from(expr);
-    if visitor.enter_node(node).is_traverse() {
-        visitor.visit_expr(expr);
-    }
-
-    visitor.leave_node(node);
+    visitor.visit_expr(expr);
 }
 
 pub fn walk_decorator<'a, V>(visitor: &mut V, decorator: &'a Decorator)

crates/ruff_python_parser/src/parser/expression.rs

@@ -1527,7 +1527,7 @@ impl<'src> Parser<'src> {
         self.bump(kind.start_token());
         let elements = self.parse_interpolated_string_elements(
             flags,
-            InterpolatedStringElementsKind::Regular,
+            InterpolatedStringElementsKind::Regular(kind),
             kind,
         );
 

crates/ruff_python_parser/src/parser/mod.rs

@@ -8,6 +8,7 @@ use ruff_text_size::{Ranged, TextRange, TextSize};
 use crate::error::UnsupportedSyntaxError;
 use crate::parser::expression::ExpressionContext;
 use crate::parser::progress::{ParserProgress, TokenId};
+use crate::string::InterpolatedStringKind;
 use crate::token::TokenValue;
 use crate::token_set::TokenSet;
 use crate::token_source::{TokenSource, TokenSourceCheckpoint};
@@ -799,7 +800,7 @@ impl WithItemKind {
     }
 }
 
-#[derive(Debug, PartialEq, Copy, Clone)]
+#[derive(Debug, PartialEq, Eq, Copy, Clone)]
 enum InterpolatedStringElementsKind {
     /// The regular f-string elements.
     ///
@@ -807,7 +808,7 @@ enum InterpolatedStringElementsKind {
     /// ```py
     /// f"hello {x:.2f} world"
     /// ```
-    Regular,
+    Regular(InterpolatedStringKind),
 
     /// The f-string elements are part of the format specifier.
     ///
@@ -819,15 +820,13 @@ enum InterpolatedStringElementsKind {
 }
 
 impl InterpolatedStringElementsKind {
-    const fn list_terminators(self) -> TokenSet {
+    const fn list_terminator(self) -> TokenKind {
         match self {
-            InterpolatedStringElementsKind::Regular => {
-                TokenSet::new([TokenKind::FStringEnd, TokenKind::TStringEnd])
-            }
+            InterpolatedStringElementsKind::Regular(string_kind) => string_kind.end_token(),
             // test_ok fstring_format_spec_terminator
             // f"hello {x:} world"
             // f"hello {x:.3f} world"
-            InterpolatedStringElementsKind::FormatSpec => TokenSet::new([TokenKind::Rbrace]),
+            InterpolatedStringElementsKind::FormatSpec => TokenKind::Rbrace,
         }
     }
 }
@@ -1121,7 +1120,7 @@ impl RecoveryContextKind {
                     .then_some(ListTerminatorKind::Regular),
             },
             RecoveryContextKind::InterpolatedStringElements(kind) => {
-                if p.at_ts(kind.list_terminators()) {
+                if p.at(kind.list_terminator()) {
                     Some(ListTerminatorKind::Regular)
                 } else {
                     // test_err unterminated_fstring_newline_recovery
@@ -1177,13 +1176,23 @@ impl RecoveryContextKind {
                 ) || p.at_name_or_soft_keyword()
             }
             RecoveryContextKind::WithItems(_) => p.at_expr(),
-            RecoveryContextKind::InterpolatedStringElements(_) => matches!(
-                p.current_token_kind(),
-                // Literal element
-                TokenKind::FStringMiddle | TokenKind::TStringMiddle
-                // Expression element
-                | TokenKind::Lbrace
-            ),
+            RecoveryContextKind::InterpolatedStringElements(elements_kind) => {
+                match elements_kind {
+                    InterpolatedStringElementsKind::Regular(interpolated_string_kind) => {
+                        p.current_token_kind() == interpolated_string_kind.middle_token()
+                            || p.current_token_kind() == TokenKind::Lbrace
+                    }
+                    InterpolatedStringElementsKind::FormatSpec => {
+                        matches!(
+                            p.current_token_kind(),
+                            // Literal element
+                            TokenKind::FStringMiddle | TokenKind::TStringMiddle
+                            // Expression element
+                            | TokenKind::Lbrace
+                        )
+                    }
+                }
+            }
         }
     }
 
@@ -1272,8 +1281,8 @@ impl RecoveryContextKind {
                 ),
             },
             RecoveryContextKind::InterpolatedStringElements(kind) => match kind {
-                InterpolatedStringElementsKind::Regular => ParseErrorType::OtherError(
-                    "Expected an f-string or t-string element or the end of the f-string or t-string".to_string(),
+                InterpolatedStringElementsKind::Regular(string_kind) => ParseErrorType::OtherError(
+                    format!("Expected an element of or the end of the {string_kind}"),
                 ),
                 InterpolatedStringElementsKind::FormatSpec => ParseErrorType::OtherError(
                     "Expected an f-string or t-string element or a '}'".to_string(),
@@ -1316,8 +1325,9 @@ bitflags! {
         const WITH_ITEMS_PARENTHESIZED = 1 << 25;
         const WITH_ITEMS_PARENTHESIZED_EXPRESSION = 1 << 26;
         const WITH_ITEMS_UNPARENTHESIZED = 1 << 28;
-        const FT_STRING_ELEMENTS = 1 << 29;
-        const FT_STRING_ELEMENTS_IN_FORMAT_SPEC = 1 << 30;
+        const F_STRING_ELEMENTS = 1 << 29;
+        const T_STRING_ELEMENTS = 1 << 30;
+        const FT_STRING_ELEMENTS_IN_FORMAT_SPEC = 1 << 31;
     }
 }
 
@@ -1371,7 +1381,13 @@ impl RecoveryContext {
                 WithItemKind::Unparenthesized => RecoveryContext::WITH_ITEMS_UNPARENTHESIZED,
             },
             RecoveryContextKind::InterpolatedStringElements(kind) => match kind {
-                InterpolatedStringElementsKind::Regular => RecoveryContext::FT_STRING_ELEMENTS,
+                InterpolatedStringElementsKind::Regular(InterpolatedStringKind::FString) => {
+                    RecoveryContext::F_STRING_ELEMENTS
+                }
+                InterpolatedStringElementsKind::Regular(InterpolatedStringKind::TString) => {
+                    RecoveryContext::T_STRING_ELEMENTS
+                }
+
                 InterpolatedStringElementsKind::FormatSpec => {
                     RecoveryContext::FT_STRING_ELEMENTS_IN_FORMAT_SPEC
                 }
@@ -1442,8 +1458,11 @@ impl RecoveryContext {
             RecoveryContext::WITH_ITEMS_UNPARENTHESIZED => {
                 RecoveryContextKind::WithItems(WithItemKind::Unparenthesized)
             }
-            RecoveryContext::FT_STRING_ELEMENTS => RecoveryContextKind::InterpolatedStringElements(
-                InterpolatedStringElementsKind::Regular,
+            RecoveryContext::F_STRING_ELEMENTS => RecoveryContextKind::InterpolatedStringElements(
+                InterpolatedStringElementsKind::Regular(InterpolatedStringKind::FString),
+            ),
+            RecoveryContext::T_STRING_ELEMENTS => RecoveryContextKind::InterpolatedStringElements(
+                InterpolatedStringElementsKind::Regular(InterpolatedStringKind::TString),
             ),
             RecoveryContext::FT_STRING_ELEMENTS_IN_FORMAT_SPEC => {
                 RecoveryContextKind::InterpolatedStringElements(

crates/ruff_python_parser/src/parser/snapshots/ruff_python_parser__parser__tests__fstring_expr_inner_line_continuation_and_t_string.snap

@@ -0,0 +1,10 @@
+---
+source: crates/ruff_python_parser/src/parser/tests.rs
+expression: error
+---
+ParseError {
+    error: Lexical(
+        LineContinuationError,
+    ),
+    location: 3..4,
+}

crates/ruff_python_parser/src/parser/snapshots/ruff_python_parser__parser__tests__fstring_expr_inner_line_continuation_newline_t_string.snap

@@ -0,0 +1,12 @@
+---
+source: crates/ruff_python_parser/src/parser/tests.rs
+expression: error
+---
+ParseError {
+    error: Lexical(
+        TStringError(
+            SingleRbrace,
+        ),
+    ),
+    location: 8..9,
+}

crates/ruff_python_parser/src/parser/tests.rs

@@ -134,3 +134,26 @@ foo.bar[0].baz[2].egg??
     .unwrap();
     insta::assert_debug_snapshot!(parsed.syntax());
 }
+
+#[test]
+fn test_fstring_expr_inner_line_continuation_and_t_string() {
+    let source = r#"f'{\t"i}'"#;
+
+    let parsed = parse_expression(source);
+
+    let error = parsed.unwrap_err();
+
+    insta::assert_debug_snapshot!(error);
+}
+
+#[test]
+fn test_fstring_expr_inner_line_continuation_newline_t_string() {
+    let source = r#"f'{\
+t"i}'"#;
+
+    let parsed = parse_expression(source);
+
+    let error = parsed.unwrap_err();
+
+    insta::assert_debug_snapshot!(error);
+}

crates/ruff_python_parser/src/string.rs

@@ -41,7 +41,7 @@ impl From<StringType> for Expr {
     }
 }
 
-#[derive(Debug, Clone, Copy)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub(crate) enum InterpolatedStringKind {
     FString,
     TString,

crates/ruff_python_parser/tests/snapshots/invalid_syntax@f_string_lambda_without_parentheses.py.snap

@@ -124,5 +124,5 @@ Module(
 
   |
 1 | f"{lambda x: x}"
-  |               ^ Syntax Error: Expected an f-string or t-string element or the end of the f-string or t-string
+  |               ^ Syntax Error: Expected an element of or the end of the f-string
   |

crates/ruff_python_parser/tests/snapshots/invalid_syntax@implicitly_concatenated_unterminated_string_multiline.py.snap

@@ -221,7 +221,7 @@ Module(
 2 |     'hello'
 3 |     f'world {x}
 4 | )
-  | ^ Syntax Error: Expected an f-string or t-string element or the end of the f-string or t-string
+  | ^ Syntax Error: Expected an element of or the end of the f-string
 5 | 1 + 1
 6 | (
   |

crates/ruff_python_parser/tests/snapshots/invalid_syntax@t_string_lambda_without_parentheses.py.snap

@@ -128,5 +128,5 @@ Module(
   |
 1 | # parse_options: {"target-version": "3.14"}
 2 | t"{lambda x: x}"
-  |               ^ Syntax Error: Expected an f-string or t-string element or the end of the f-string or t-string
+  |               ^ Syntax Error: Expected an element of or the end of the t-string
   |

crates/ruff_python_semantic/src/analyze/visibility.rs

@@ -163,7 +163,7 @@ fn stem(path: &str) -> &str {
 }
 
 /// Infer the [`Visibility`] of a module from its path.
-pub(crate) fn module_visibility(module: &Module) -> Visibility {
+pub(crate) fn module_visibility(module: Module) -> Visibility {
     match &module.source {
         ModuleSource::Path(path) => {
             if path.iter().any(|m| is_private_module(m)) {

crates/ruff_python_semantic/src/definition.rs

@@ -223,7 +223,7 @@ impl<'a> Definitions<'a> {
             // visibility.
             let visibility = {
                 match &definition {
-                    Definition::Module(module) => module_visibility(module),
+                    Definition::Module(module) => module_visibility(*module),
                     Definition::Member(member) => match member.kind {
                         MemberKind::Class(class) => {
                             let parent = &definitions[member.parent];

crates/ruff_server/src/lint.rs

@@ -238,7 +238,7 @@ fn to_lsp_diagnostic(
     let name = diagnostic.name();
     let body = diagnostic.body().to_string();
     let fix = diagnostic.fix();
-    let suggestion = diagnostic.suggestion();
+    let suggestion = diagnostic.first_help_text();
     let code = diagnostic.secondary_code();
 
     let fix = fix.and_then(|fix| fix.applies(Applicability::Unsafe).then_some(fix));

crates/ruff_wasm/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ruff_wasm"
-version = "0.12.4"
+version = "0.12.5"
 publish = false
 authors = { workspace = true }
 edition = { workspace = true }

crates/ruff_wasm/src/lib.rs

@@ -234,7 +234,7 @@ impl Workspace {
                 start_location: source_code.line_column(msg.expect_range().start()).into(),
                 end_location: source_code.line_column(msg.expect_range().end()).into(),
                 fix: msg.fix().map(|fix| ExpandedFix {
-                    message: msg.suggestion().map(ToString::to_string),
+                    message: msg.first_help_text().map(ToString::to_string),
                     edits: fix
                         .edits()
                         .iter()

crates/ty/docs/rules.md

@@ -16,7 +16,7 @@ Checks for byte-strings in type annotation positions.
 
 **Why is this bad?**
 
-Static analysis tools like ty can't analyse type annotations that use byte-string notation.
+Static analysis tools like ty can't analyze type annotations that use byte-string notation.
 
 **Examples**
 
@@ -257,7 +257,7 @@ Checks for f-strings in type annotation positions.
 
 **Why is this bad?**
 
-Static analysis tools like ty can't analyse type annotations that use f-string notation.
+Static analysis tools like ty can't analyze type annotations that use f-string notation.
 
 **Examples**
 
@@ -286,7 +286,7 @@ Checks for implicit concatenated strings in type annotation positions.
 
 **Why is this bad?**
 
-Static analysis tools like ty can't analyse type annotations that use implicit concatenated strings.
+Static analysis tools like ty can't analyze type annotations that use implicit concatenated strings.
 
 **Examples**
 
@@ -1276,7 +1276,7 @@ Checks for raw-strings in type annotation positions.
 
 **Why is this bad?**
 
-Static analysis tools like ty can't analyse type annotations that use raw-string notation.
+Static analysis tools like ty can't analyze type annotations that use raw-string notation.
 
 **Examples**
 

crates/ty/src/lib.rs

@@ -156,7 +156,12 @@ fn run_check(args: CheckCommand) -> anyhow::Result<ExitStatus> {
         Ok("short") => write!(stdout, "{}", db.salsa_memory_dump().display_short())?,
         Ok("mypy_primer") => write!(stdout, "{}", db.salsa_memory_dump().display_mypy_primer())?,
         Ok("full") => write!(stdout, "{}", db.salsa_memory_dump().display_full())?,
-        _ => {}
+        Ok(other) => {
+            tracing::warn!(
+                "Unknown value for `TY_MEMORY_REPORT`: `{other}`. Valid values are `short`, `mypy_primer`, and `full`."
+            );
+        }
+        Err(_) => {}
     }
 
     std::mem::forget(db);

crates/ty/tests/cli/file_selection.rs

@@ -676,7 +676,7 @@ fn invalid_include_pattern_concise_output() -> anyhow::Result<()> {
     ----- stderr -----
     WARN ty is pre-release software and not ready for production use. Expect to encounter bugs, missing features, and fatal errors.
     ty failed
-      Cause: error[invalid-glob] ty.toml:4:5: Invalid include pattern: Too many stars at position 5
+      Cause: ty.toml:4:5: error[invalid-glob] Invalid include pattern: Too many stars at position 5
     ");
 
     Ok(())

crates/ty/tests/cli/main.rs

@@ -592,8 +592,8 @@ fn concise_diagnostics() -> anyhow::Result<()> {
     success: false
     exit_code: 1
     ----- stdout -----
-    warning[unresolved-reference] test.py:2:7: Name `x` used when not defined
-    error[non-subscriptable] test.py:3:7: Cannot subscript object of type `Literal[4]` with no `__getitem__` method
+    test.py:2:7: warning[unresolved-reference] Name `x` used when not defined
+    test.py:3:7: error[non-subscriptable] Cannot subscript object of type `Literal[4]` with no `__getitem__` method
     Found 2 diagnostics
 
     ----- stderr -----
@@ -627,7 +627,7 @@ fn concise_revealed_type() -> anyhow::Result<()> {
     success: true
     exit_code: 0
     ----- stdout -----
-    info[revealed-type] test.py:5:13: Revealed type: `Literal["hello"]`
+    test.py:5:13: info[revealed-type] Revealed type: `Literal["hello"]`
     Found 1 diagnostic
 
     ----- stderr -----

crates/ty/tests/file_watching.rs

@@ -230,6 +230,21 @@ impl TestCase {
     fn system_file(&self, path: impl AsRef<SystemPath>) -> Result<File, FileError> {
         system_path_to_file(self.db(), path.as_ref())
     }
+
+    fn module<'c>(&'c self, name: &str) -> Module<'c> {
+        resolve_module(self.db(), &ModuleName::new(name).unwrap()).expect("module to be present")
+    }
+
+    fn sorted_submodule_names(&self, parent_module_name: &str) -> Vec<String> {
+        let mut names = self
+            .module(parent_module_name)
+            .all_submodules(self.db())
+            .iter()
+            .map(|name| name.as_str().to_string())
+            .collect::<Vec<String>>();
+        names.sort();
+        names
+    }
 }
 
 trait MatchEvent {
@@ -1398,7 +1413,7 @@ mod unix {
         let baz = resolve_module(case.db(), &ModuleName::new_static("bar.baz").unwrap())
             .expect("Expected bar.baz to exist in site-packages.");
         let baz_project = case.project_path("bar/baz.py");
-        let baz_file = baz.file().unwrap();
+        let baz_file = baz.file(case.db()).unwrap();
 
         assert_eq!(source_text(case.db(), baz_file).as_str(), "def baz(): ...");
         assert_eq!(
@@ -1473,7 +1488,7 @@ mod unix {
 
         let baz = resolve_module(case.db(), &ModuleName::new_static("bar.baz").unwrap())
             .expect("Expected bar.baz to exist in site-packages.");
-        let baz_file = baz.file().unwrap();
+        let baz_file = baz.file(case.db()).unwrap();
         let bar_baz = case.project_path("bar/baz.py");
 
         let patched_bar_baz = case.project_path("patched/bar/baz.py");
@@ -1594,7 +1609,10 @@ mod unix {
             "def baz(): ..."
         );
         assert_eq!(
-            baz.file().unwrap().path(case.db()).as_system_path(),
+            baz.file(case.db())
+                .unwrap()
+                .path(case.db())
+                .as_system_path(),
             Some(&*baz_original)
         );
 
@@ -1891,19 +1909,9 @@ fn rename_files_casing_only() -> anyhow::Result<()> {
 #[test]
 fn submodule_cache_invalidation_created() -> anyhow::Result<()> {
     let mut case = setup([("lib.py", ""), ("bar/__init__.py", ""), ("bar/foo.py", "")])?;
-    let module = resolve_module(case.db(), &ModuleName::new("bar").unwrap()).expect("`bar` module");
-    let get_submodules = |db: &dyn Db, module: &Module| {
-        let mut names = module
-            .all_submodules(db)
-            .iter()
-            .map(|name| name.as_str().to_string())
-            .collect::<Vec<String>>();
-        names.sort();
-        names.join("\n")
-    };
 
     insta::assert_snapshot!(
-        get_submodules(case.db(), &module),
+        case.sorted_submodule_names("bar").join("\n"),
         @"foo",
     );
 
@@ -1912,7 +1920,7 @@ fn submodule_cache_invalidation_created() -> anyhow::Result<()> {
     case.apply_changes(changes, None);
 
     insta::assert_snapshot!(
-        get_submodules(case.db(), &module),
+        case.sorted_submodule_names("bar").join("\n"),
         @r"
     foo
     wazoo
@@ -1932,19 +1940,9 @@ fn submodule_cache_invalidation_deleted() -> anyhow::Result<()> {
         ("bar/foo.py", ""),
         ("bar/wazoo.py", ""),
     ])?;
-    let module = resolve_module(case.db(), &ModuleName::new("bar").unwrap()).expect("`bar` module");
-    let get_submodules = |db: &dyn Db, module: &Module| {
-        let mut names = module
-            .all_submodules(db)
-            .iter()
-            .map(|name| name.as_str().to_string())
-            .collect::<Vec<String>>();
-        names.sort();
-        names.join("\n")
-    };
 
     insta::assert_snapshot!(
-        get_submodules(case.db(), &module),
+        case.sorted_submodule_names("bar").join("\n"),
         @r"
     foo
     wazoo
@@ -1956,7 +1954,7 @@ fn submodule_cache_invalidation_deleted() -> anyhow::Result<()> {
     case.apply_changes(changes, None);
 
     insta::assert_snapshot!(
-        get_submodules(case.db(), &module),
+        case.sorted_submodule_names("bar").join("\n"),
         @"foo",
     );
 
@@ -1968,19 +1966,9 @@ fn submodule_cache_invalidation_deleted() -> anyhow::Result<()> {
 #[test]
 fn submodule_cache_invalidation_created_then_deleted() -> anyhow::Result<()> {
     let mut case = setup([("lib.py", ""), ("bar/__init__.py", ""), ("bar/foo.py", "")])?;
-    let module = resolve_module(case.db(), &ModuleName::new("bar").unwrap()).expect("`bar` module");
-    let get_submodules = |db: &dyn Db, module: &Module| {
-        let mut names = module
-            .all_submodules(db)
-            .iter()
-            .map(|name| name.as_str().to_string())
-            .collect::<Vec<String>>();
-        names.sort();
-        names.join("\n")
-    };
 
     insta::assert_snapshot!(
-        get_submodules(case.db(), &module),
+        case.sorted_submodule_names("bar").join("\n"),
         @"foo",
     );
 
@@ -1993,7 +1981,7 @@ fn submodule_cache_invalidation_created_then_deleted() -> anyhow::Result<()> {
     case.apply_changes(changes, None);
 
     insta::assert_snapshot!(
-        get_submodules(case.db(), &module),
+        case.sorted_submodule_names("bar").join("\n"),
         @"foo",
     );
 
@@ -2006,19 +1994,9 @@ fn submodule_cache_invalidation_created_then_deleted() -> anyhow::Result<()> {
 #[test]
 fn submodule_cache_invalidation_after_pyproject_created() -> anyhow::Result<()> {
     let mut case = setup([("lib.py", ""), ("bar/__init__.py", ""), ("bar/foo.py", "")])?;
-    let module = resolve_module(case.db(), &ModuleName::new("bar").unwrap()).expect("`bar` module");
-    let get_submodules = |db: &dyn Db, module: &Module| {
-        let mut names = module
-            .all_submodules(db)
-            .iter()
-            .map(|name| name.as_str().to_string())
-            .collect::<Vec<String>>();
-        names.sort();
-        names.join("\n")
-    };
 
     insta::assert_snapshot!(
-        get_submodules(case.db(), &module),
+        case.sorted_submodule_names("bar").join("\n"),
         @"foo",
     );
 
@@ -2029,7 +2007,7 @@ fn submodule_cache_invalidation_after_pyproject_created() -> anyhow::Result<()>
     case.apply_changes(changes, None);
 
     insta::assert_snapshot!(
-        get_submodules(case.db(), &module),
+        case.sorted_submodule_names("bar").join("\n"),
         @r"
     foo
     wazoo

crates/ty_ide/Cargo.toml

@@ -19,15 +19,15 @@ ruff_python_trivia = { workspace = true }
 ruff_source_file = { workspace = true }
 ruff_text_size = { workspace = true }
 ty_python_semantic = { workspace = true }
+ty_project = { workspace = true, features = ["testing"] }
 
+itertools = { workspace = true }
 regex = { workspace = true }
 rustc-hash = { workspace = true }
-salsa = { workspace = true }
 smallvec = { workspace = true }
 tracing = { workspace = true }
 
 [dev-dependencies]
-ty_vendored = { workspace = true }
 
 insta = { workspace = true, features = ["filters"] }
 

crates/ty_ide/src/completion.rs

@@ -1618,6 +1618,8 @@ Answer.<CURSOR>
                 __text_signature__ :: str | None
                 __type_params__ :: tuple[TypeVar | ParamSpec | TypeVarTuple, ...]
                 __weakrefoffset__ :: int
+                _add_alias_ :: def _add_alias_(self, name: str) -> None
+                _add_value_alias_ :: def _add_value_alias_(self, value: Any) -> None
                 _generate_next_value_ :: def _generate_next_value_(name: str, start: int, count: int, last_values: list[Any]) -> Any
                 _ignore_ :: str | list[str]
                 _member_map_ :: dict[str, Enum]

crates/ty_ide/src/db.rs

@@ -1,117 +0,0 @@
-use ty_python_semantic::Db as SemanticDb;
-
-#[salsa::db]
-pub trait Db: SemanticDb {}
-
-#[cfg(test)]
-pub(crate) mod tests {
-    use std::sync::{Arc, Mutex};
-
-    use super::Db;
-    use ruff_db::Db as SourceDb;
-    use ruff_db::files::{File, Files};
-    use ruff_db::system::{DbWithTestSystem, System, TestSystem};
-    use ruff_db::vendored::VendoredFileSystem;
-    use ty_python_semantic::lint::{LintRegistry, RuleSelection};
-    use ty_python_semantic::{Db as SemanticDb, Program, default_lint_registry};
-
-    type Events = Arc<Mutex<Vec<salsa::Event>>>;
-
-    #[salsa::db]
-    #[derive(Clone)]
-    pub(crate) struct TestDb {
-        storage: salsa::Storage<Self>,
-        files: Files,
-        system: TestSystem,
-        vendored: VendoredFileSystem,
-        events: Events,
-        rule_selection: Arc<RuleSelection>,
-    }
-
-    #[expect(dead_code)]
-    impl TestDb {
-        pub(crate) fn new() -> Self {
-            let events = Events::default();
-            Self {
-                storage: salsa::Storage::new(Some(Box::new({
-                    let events = events.clone();
-                    move |event| {
-                        tracing::trace!("event: {event:?}");
-                        let mut events = events.lock().unwrap();
-                        events.push(event);
-                    }
-                }))),
-                system: TestSystem::default(),
-                vendored: ty_vendored::file_system().clone(),
-                events,
-                files: Files::default(),
-                rule_selection: Arc::new(RuleSelection::from_registry(default_lint_registry())),
-            }
-        }
-
-        /// Takes the salsa events.
-        pub(crate) fn take_salsa_events(&mut self) -> Vec<salsa::Event> {
-            let mut events = self.events.lock().unwrap();
-
-            std::mem::take(&mut *events)
-        }
-
-        /// Clears the salsa events.
-        ///
-        /// ## Panics
-        /// If there are any pending salsa snapshots.
-        pub(crate) fn clear_salsa_events(&mut self) {
-            self.take_salsa_events();
-        }
-    }
-
-    impl DbWithTestSystem for TestDb {
-        fn test_system(&self) -> &TestSystem {
-            &self.system
-        }
-
-        fn test_system_mut(&mut self) -> &mut TestSystem {
-            &mut self.system
-        }
-    }
-
-    #[salsa::db]
-    impl SourceDb for TestDb {
-        fn vendored(&self) -> &VendoredFileSystem {
-            &self.vendored
-        }
-
-        fn system(&self) -> &dyn System {
-            &self.system
-        }
-
-        fn files(&self) -> &Files {
-            &self.files
-        }
-
-        fn python_version(&self) -> ruff_python_ast::PythonVersion {
-            Program::get(self).python_version(self)
-        }
-    }
-
-    #[salsa::db]
-    impl SemanticDb for TestDb {
-        fn should_check_file(&self, file: File) -> bool {
-            !file.path(self).is_vendored_path()
-        }
-
-        fn rule_selection(&self, _file: File) -> &RuleSelection {
-            &self.rule_selection
-        }
-
-        fn lint_registry(&self) -> &LintRegistry {
-            default_lint_registry()
-        }
-    }
-
-    #[salsa::db]
-    impl Db for TestDb {}
-
-    #[salsa::db]
-    impl salsa::Database for TestDb {}
-}

crates/ty_ide/src/find_node.rs

@@ -52,9 +52,7 @@ pub(crate) fn covering_node(root: AnyNodeRef, range: TextRange) -> CoveringNode
     if visitor.ancestors.is_empty() {
         visitor.ancestors.push(root);
     }
-    CoveringNode {
-        nodes: visitor.ancestors,
-    }
+    CoveringNode::from_ancestors(visitor.ancestors)
 }
 
 /// The node with a minimal range that fully contains the search range.
@@ -67,6 +65,12 @@ pub(crate) struct CoveringNode<'a> {
 }
 
 impl<'a> CoveringNode<'a> {
+    /// Creates a new `CoveringNode` from a list of ancestor nodes.
+    /// The ancestors should be ordered from root to the covering node.
+    pub(crate) fn from_ancestors(ancestors: Vec<AnyNodeRef<'a>>) -> Self {
+        Self { nodes: ancestors }
+    }
+
     /// Returns the covering node found.
     pub(crate) fn node(&self) -> AnyNodeRef<'a> {
         *self
@@ -112,6 +116,12 @@ impl<'a> CoveringNode<'a> {
         Ok(self)
     }
 
+    /// Returns an iterator over the ancestor nodes, starting from the root
+    /// and ending with the covering node.
+    pub(crate) fn ancestors(&self) -> impl Iterator<Item = AnyNodeRef<'a>> + '_ {
+        self.nodes.iter().copied()
+    }
+
     /// Finds the index of the node that fully covers the range and
     /// fulfills the given predicate.
     ///

crates/ty_ide/src/goto.rs

@@ -2,30 +2,62 @@ pub use crate::goto_declaration::goto_declaration;
 pub use crate::goto_definition::goto_definition;
 pub use crate::goto_type_definition::goto_type_definition;
 
+use std::borrow::Cow;
+
 use crate::find_node::covering_node;
 use crate::stub_mapping::StubMapper;
-use ruff_db::parsed::{ParsedModuleRef, parsed_module};
+use ruff_db::parsed::ParsedModuleRef;
 use ruff_python_ast::{self as ast, AnyNodeRef};
 use ruff_python_parser::TokenKind;
 use ruff_text_size::{Ranged, TextRange, TextSize};
 use ty_python_semantic::types::Type;
 use ty_python_semantic::types::definitions_for_keyword_argument;
-use ty_python_semantic::{HasType, SemanticModel, definitions_for_name};
+use ty_python_semantic::{
+    HasType, SemanticModel, definitions_for_imported_symbol, definitions_for_name,
+};
 
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Debug)]
 pub(crate) enum GotoTarget<'a> {
     Expression(ast::ExprRef<'a>),
     FunctionDef(&'a ast::StmtFunctionDef),
     ClassDef(&'a ast::StmtClassDef),
     Parameter(&'a ast::Parameter),
-    Alias(&'a ast::Alias),
 
-    /// Go to on the module name of an import from
+    /// Multi-part module names
+    /// Handles both `import foo.bar` and `from foo.bar import baz` cases
     /// ```py
-    /// from foo import bar
-    ///      ^^^
+    /// import foo.bar
+    ///        ^^^
+    /// from foo.bar import baz
+    ///          ^^^
     /// ```
-    ImportedModule(&'a ast::StmtImportFrom),
+    ImportModuleComponent {
+        module_name: String,
+        component_index: usize,
+        component_range: TextRange,
+    },
+
+    /// Import alias in standard import statement
+    /// ```py
+    /// import foo.bar as baz
+    ///                   ^^^
+    /// ```
+    ImportModuleAlias {
+        alias: &'a ast::Alias,
+    },
+
+    /// Import alias in from import statement
+    /// ```py
+    /// from foo import bar as baz
+    ///                 ^^^
+    /// from foo import bar as baz
+    ///                        ^^^
+    /// ```
+    ImportSymbolAlias {
+        alias: &'a ast::Alias,
+        range: TextRange,
+        import_from: &'a ast::StmtImportFrom,
+    },
 
     /// Go to on the exception handler variable
     /// ```py
@@ -40,7 +72,10 @@ pub(crate) enum GotoTarget<'a> {
     /// test(a = 1)
     ///      ^
     /// ```
-    KeywordArgument(&'a ast::Keyword),
+    KeywordArgument {
+        keyword: &'a ast::Keyword,
+        call_expression: &'a ast::ExprCall,
+    },
 
     /// Go to on the rest parameter of a pattern match
     ///
@@ -109,25 +144,22 @@ pub(crate) enum GotoTarget<'a> {
 }
 
 impl GotoTarget<'_> {
-    pub(crate) fn inferred_type<'db>(self, model: &SemanticModel<'db>) -> Option<Type<'db>> {
+    pub(crate) fn inferred_type<'db>(&self, model: &SemanticModel<'db>) -> Option<Type<'db>> {
         let ty = match self {
             GotoTarget::Expression(expression) => expression.inferred_type(model),
             GotoTarget::FunctionDef(function) => function.inferred_type(model),
             GotoTarget::ClassDef(class) => class.inferred_type(model),
             GotoTarget::Parameter(parameter) => parameter.inferred_type(model),
-            GotoTarget::Alias(alias) => alias.inferred_type(model),
+            GotoTarget::ImportSymbolAlias { alias, .. } => alias.inferred_type(model),
+            GotoTarget::ImportModuleAlias { alias } => alias.inferred_type(model),
             GotoTarget::ExceptVariable(except) => except.inferred_type(model),
-            GotoTarget::KeywordArgument(argument) => {
-                // TODO: Pyright resolves the declared type of the matching parameter. This seems more accurate
-                // than using the inferred value.
-                argument.value.inferred_type(model)
-            }
+            GotoTarget::KeywordArgument { keyword, .. } => keyword.value.inferred_type(model),
             // TODO: Support identifier targets
             GotoTarget::PatternMatchRest(_)
             | GotoTarget::PatternKeywordArgument(_)
             | GotoTarget::PatternMatchStarName(_)
             | GotoTarget::PatternMatchAsName(_)
-            | GotoTarget::ImportedModule(_)
+            | GotoTarget::ImportModuleComponent { .. }
             | GotoTarget::TypeParamTypeVarName(_)
             | GotoTarget::TypeParamParamSpecName(_)
             | GotoTarget::TypeParamTypeVarTupleName(_)
@@ -142,7 +174,7 @@ impl GotoTarget<'_> {
     /// If a stub mapper is provided, definitions from stub files will be mapped to
     /// their corresponding source file implementations.
     pub(crate) fn get_definition_targets(
-        self,
+        &self,
         file: ruff_db::files::File,
         db: &dyn crate::Db,
         stub_mapper: Option<&StubMapper>,
@@ -193,38 +225,317 @@ impl GotoTarget<'_> {
                 }))
             }
 
-            // For imports, find the symbol being imported
-            GotoTarget::Alias(_alias) => {
-                // For aliases, we don't have the ExprName node, so we can't get the scope
-                // For now, return None. In the future, we could look up the imported symbol
-                None
+            // For import aliases (offset within 'y' or 'z' in "from x import y as z")
+            GotoTarget::ImportSymbolAlias {
+                alias, import_from, ..
+            } => {
+                // Handle both original names and alias names in `from x import y as z` statements
+                let symbol_name = alias.name.as_str();
+                let definitions =
+                    definitions_for_imported_symbol(db, file, import_from, symbol_name);
+
+                definitions_to_navigation_targets(db, stub_mapper, definitions)
+            }
+
+            GotoTarget::ImportModuleComponent {
+                module_name,
+                component_index,
+                ..
+            } => {
+                // Handle both `import foo.bar` and `from foo.bar import baz` where offset is within module component
+                let components: Vec<&str> = module_name.split('.').collect();
+
+                // Build the module name up to and including the component containing the offset
+                let target_module_name = components[..=*component_index].join(".");
+
+                // Try to resolve the module
+                resolve_module_to_navigation_target(db, &target_module_name)
+            }
+
+            // Handle import aliases (offset within 'z' in "import x.y as z")
+            GotoTarget::ImportModuleAlias { alias } => {
+                // For import aliases, navigate to the module being aliased
+                // This only applies to regular import statements like "import x.y as z"
+                let full_module_name = alias.name.as_str();
+
+                // Try to resolve the module
+                resolve_module_to_navigation_target(db, full_module_name)
             }
 
             // Handle keyword arguments in call expressions
-            GotoTarget::KeywordArgument(keyword) => {
-                // Find the call expression that contains this keyword
-                let module = parsed_module(db, file).load(db);
-
-                // Use the keyword's range to find the containing call expression
-                let covering_node = covering_node(module.syntax().into(), keyword.range())
-                    .find_first(|node| matches!(node, AnyNodeRef::ExprCall(_)))
-                    .ok()?;
-
-                if let AnyNodeRef::ExprCall(call_expr) = covering_node.node() {
-                    let definitions =
-                        definitions_for_keyword_argument(db, file, keyword, call_expr);
-                    return definitions_to_navigation_targets(db, stub_mapper, definitions);
-                }
-
-                None
+            GotoTarget::KeywordArgument {
+                keyword,
+                call_expression,
+            } => {
+                let definitions =
+                    definitions_for_keyword_argument(db, file, keyword, call_expression);
+                definitions_to_navigation_targets(db, stub_mapper, definitions)
+            }
+
+            // For exception variables, they are their own definitions (like parameters)
+            GotoTarget::ExceptVariable(except_handler) => {
+                if let Some(name) = &except_handler.name {
+                    let range = name.range;
+                    Some(crate::NavigationTargets::single(NavigationTarget::new(
+                        file, range,
+                    )))
+                } else {
+                    None
+                }
+            }
+
+            // For pattern match rest variables, they are their own definitions
+            GotoTarget::PatternMatchRest(pattern_mapping) => {
+                if let Some(rest_name) = &pattern_mapping.rest {
+                    let range = rest_name.range;
+                    Some(crate::NavigationTargets::single(NavigationTarget::new(
+                        file, range,
+                    )))
+                } else {
+                    None
+                }
+            }
+
+            // For pattern match as names, they are their own definitions
+            GotoTarget::PatternMatchAsName(pattern_as) => {
+                if let Some(name) = &pattern_as.name {
+                    let range = name.range;
+                    Some(crate::NavigationTargets::single(NavigationTarget::new(
+                        file, range,
+                    )))
+                } else {
+                    None
+                }
             }
 
-            // TODO: Handle multi-part module names in import statements
-            // TODO: Handle imported symbol in y in `from x import y as z` statement
             // TODO: Handle string literals that map to TypedDict fields
             _ => None,
         }
     }
+
+    /// Returns the text representation of this goto target.
+    /// Returns `None` if no meaningful string representation can be provided.
+    /// This is used by the "references" feature, which looks for references
+    /// to this goto target.
+    pub(crate) fn to_string(&self) -> Option<Cow<str>> {
+        match self {
+            GotoTarget::Expression(expression) => match expression {
+                ast::ExprRef::Name(name) => Some(Cow::Borrowed(name.id.as_str())),
+                ast::ExprRef::Attribute(attr) => Some(Cow::Borrowed(attr.attr.as_str())),
+                _ => None,
+            },
+            GotoTarget::FunctionDef(function) => Some(Cow::Borrowed(function.name.as_str())),
+            GotoTarget::ClassDef(class) => Some(Cow::Borrowed(class.name.as_str())),
+            GotoTarget::Parameter(parameter) => Some(Cow::Borrowed(parameter.name.as_str())),
+            GotoTarget::ImportSymbolAlias { alias, .. } => {
+                if let Some(asname) = &alias.asname {
+                    Some(Cow::Borrowed(asname.as_str()))
+                } else {
+                    Some(Cow::Borrowed(alias.name.as_str()))
+                }
+            }
+            GotoTarget::ImportModuleComponent {
+                module_name,
+                component_index,
+                ..
+            } => {
+                let components: Vec<&str> = module_name.split('.').collect();
+                if let Some(component) = components.get(*component_index) {
+                    Some(Cow::Borrowed(*component))
+                } else {
+                    Some(Cow::Borrowed(module_name))
+                }
+            }
+            GotoTarget::ImportModuleAlias { alias } => {
+                if let Some(asname) = &alias.asname {
+                    Some(Cow::Borrowed(asname.as_str()))
+                } else {
+                    Some(Cow::Borrowed(alias.name.as_str()))
+                }
+            }
+            GotoTarget::ExceptVariable(except) => {
+                Some(Cow::Borrowed(except.name.as_ref()?.as_str()))
+            }
+            GotoTarget::KeywordArgument { keyword, .. } => {
+                Some(Cow::Borrowed(keyword.arg.as_ref()?.as_str()))
+            }
+            GotoTarget::PatternMatchRest(rest) => Some(Cow::Borrowed(rest.rest.as_ref()?.as_str())),
+            GotoTarget::PatternKeywordArgument(keyword) => {
+                Some(Cow::Borrowed(keyword.attr.as_str()))
+            }
+            GotoTarget::PatternMatchStarName(star) => {
+                Some(Cow::Borrowed(star.name.as_ref()?.as_str()))
+            }
+            GotoTarget::PatternMatchAsName(as_name) => {
+                Some(Cow::Borrowed(as_name.name.as_ref()?.as_str()))
+            }
+            GotoTarget::TypeParamTypeVarName(type_var) => {
+                Some(Cow::Borrowed(type_var.name.as_str()))
+            }
+            GotoTarget::TypeParamParamSpecName(spec) => Some(Cow::Borrowed(spec.name.as_str())),
+            GotoTarget::TypeParamTypeVarTupleName(tuple) => {
+                Some(Cow::Borrowed(tuple.name.as_str()))
+            }
+            GotoTarget::NonLocal { identifier, .. } => Some(Cow::Borrowed(identifier.as_str())),
+            GotoTarget::Globals { identifier, .. } => Some(Cow::Borrowed(identifier.as_str())),
+        }
+    }
+
+    /// Creates a `GotoTarget` from a `CoveringNode` and an offset within the node
+    pub(crate) fn from_covering_node<'a>(
+        covering_node: &crate::find_node::CoveringNode<'a>,
+        offset: TextSize,
+    ) -> Option<GotoTarget<'a>> {
+        tracing::trace!("Covering node is of kind {:?}", covering_node.node().kind());
+
+        match covering_node.node() {
+            AnyNodeRef::Identifier(identifier) => match covering_node.parent() {
+                Some(AnyNodeRef::StmtFunctionDef(function)) => {
+                    Some(GotoTarget::FunctionDef(function))
+                }
+                Some(AnyNodeRef::StmtClassDef(class)) => Some(GotoTarget::ClassDef(class)),
+                Some(AnyNodeRef::Parameter(parameter)) => Some(GotoTarget::Parameter(parameter)),
+                Some(AnyNodeRef::Alias(alias)) => {
+                    // Find the containing import statement to determine the type
+                    let import_stmt = covering_node.ancestors().find(|node| {
+                        matches!(
+                            node,
+                            AnyNodeRef::StmtImport(_) | AnyNodeRef::StmtImportFrom(_)
+                        )
+                    });
+
+                    match import_stmt {
+                        Some(AnyNodeRef::StmtImport(_)) => {
+                            // Regular import statement like "import x.y as z"
+
+                            // Is the offset within the alias name (asname) part?
+                            if let Some(asname) = &alias.asname {
+                                if asname.range.contains_inclusive(offset) {
+                                    return Some(GotoTarget::ImportModuleAlias { alias });
+                                }
+                            }
+
+                            // Is the offset in the module name part?
+                            if alias.name.range.contains_inclusive(offset) {
+                                let full_name = alias.name.as_str();
+
+                                if let Some((component_index, component_range)) =
+                                    find_module_component(
+                                        full_name,
+                                        alias.name.range.start(),
+                                        offset,
+                                    )
+                                {
+                                    return Some(GotoTarget::ImportModuleComponent {
+                                        module_name: full_name.to_string(),
+                                        component_index,
+                                        component_range,
+                                    });
+                                }
+                            }
+
+                            None
+                        }
+                        Some(AnyNodeRef::StmtImportFrom(import_from)) => {
+                            // From import statement like "from x import y as z"
+
+                            // Is the offset within the alias name (asname) part?
+                            if let Some(asname) = &alias.asname {
+                                if asname.range.contains_inclusive(offset) {
+                                    return Some(GotoTarget::ImportSymbolAlias {
+                                        alias,
+                                        range: asname.range,
+                                        import_from,
+                                    });
+                                }
+                            }
+
+                            // Is the offset in the original name part?
+                            if alias.name.range.contains_inclusive(offset) {
+                                return Some(GotoTarget::ImportSymbolAlias {
+                                    alias,
+                                    range: alias.name.range,
+                                    import_from,
+                                });
+                            }
+
+                            None
+                        }
+                        _ => None,
+                    }
+                }
+                Some(AnyNodeRef::StmtImportFrom(from)) => {
+                    // Handle offset within module name in from import statements
+                    if let Some(module_expr) = &from.module {
+                        let full_module_name = module_expr.to_string();
+
+                        if let Some((component_index, component_range)) = find_module_component(
+                            &full_module_name,
+                            module_expr.range.start(),
+                            offset,
+                        ) {
+                            return Some(GotoTarget::ImportModuleComponent {
+                                module_name: full_module_name,
+                                component_index,
+                                component_range,
+                            });
+                        }
+                    }
+
+                    None
+                }
+                Some(AnyNodeRef::ExceptHandlerExceptHandler(handler)) => {
+                    Some(GotoTarget::ExceptVariable(handler))
+                }
+                Some(AnyNodeRef::Keyword(keyword)) => {
+                    // Find the containing call expression from the ancestor chain
+                    let call_expression = covering_node
+                        .ancestors()
+                        .find_map(ruff_python_ast::AnyNodeRef::expr_call)?;
+                    Some(GotoTarget::KeywordArgument {
+                        keyword,
+                        call_expression,
+                    })
+                }
+                Some(AnyNodeRef::PatternMatchMapping(mapping)) => {
+                    Some(GotoTarget::PatternMatchRest(mapping))
+                }
+                Some(AnyNodeRef::PatternKeyword(keyword)) => {
+                    Some(GotoTarget::PatternKeywordArgument(keyword))
+                }
+                Some(AnyNodeRef::PatternMatchStar(star)) => {
+                    Some(GotoTarget::PatternMatchStarName(star))
+                }
+                Some(AnyNodeRef::PatternMatchAs(as_pattern)) => {
+                    Some(GotoTarget::PatternMatchAsName(as_pattern))
+                }
+                Some(AnyNodeRef::TypeParamTypeVar(var)) => {
+                    Some(GotoTarget::TypeParamTypeVarName(var))
+                }
+                Some(AnyNodeRef::TypeParamParamSpec(bound)) => {
+                    Some(GotoTarget::TypeParamParamSpecName(bound))
+                }
+                Some(AnyNodeRef::TypeParamTypeVarTuple(var_tuple)) => {
+                    Some(GotoTarget::TypeParamTypeVarTupleName(var_tuple))
+                }
+                Some(AnyNodeRef::ExprAttribute(attribute)) => {
+                    Some(GotoTarget::Expression(attribute.into()))
+                }
+                Some(AnyNodeRef::StmtNonlocal(_)) => Some(GotoTarget::NonLocal { identifier }),
+                Some(AnyNodeRef::StmtGlobal(_)) => Some(GotoTarget::Globals { identifier }),
+                None => None,
+                Some(parent) => {
+                    tracing::debug!(
+                        "Missing `GoToTarget` for identifier with parent {:?}",
+                        parent.kind()
+                    );
+                    None
+                }
+            },
+
+            node => node.as_expr_ref().map(GotoTarget::Expression),
+        }
+    }
 }
 
 impl Ranged for GotoTarget<'_> {
@@ -234,10 +545,13 @@ impl Ranged for GotoTarget<'_> {
             GotoTarget::FunctionDef(function) => function.name.range,
             GotoTarget::ClassDef(class) => class.name.range,
             GotoTarget::Parameter(parameter) => parameter.name.range,
-            GotoTarget::Alias(alias) => alias.name.range,
-            GotoTarget::ImportedModule(module) => module.module.as_ref().unwrap().range,
+            GotoTarget::ImportSymbolAlias { range, .. } => *range,
+            GotoTarget::ImportModuleComponent {
+                component_range, ..
+            } => *component_range,
+            GotoTarget::ImportModuleAlias { alias } => alias.asname.as_ref().unwrap().range,
             GotoTarget::ExceptVariable(except) => except.name.as_ref().unwrap().range,
-            GotoTarget::KeywordArgument(keyword) => keyword.arg.as_ref().unwrap().range,
+            GotoTarget::KeywordArgument { keyword, .. } => keyword.arg.as_ref().unwrap().range,
             GotoTarget::PatternMatchRest(rest) => rest.rest.as_ref().unwrap().range,
             GotoTarget::PatternKeywordArgument(keyword) => keyword.attr.range,
             GotoTarget::PatternMatchStarName(star) => star.name.as_ref().unwrap().range,
@@ -276,11 +590,7 @@ fn convert_resolved_definitions_to_targets(
             }
             ty_python_semantic::ResolvedDefinition::FileWithRange(file_range) => {
                 // For file ranges, navigate to the specific range within the file
-                crate::NavigationTarget {
-                    file: file_range.file(),
-                    focus_range: file_range.range(),
-                    full_range: file_range.range(),
-                }
+                crate::NavigationTarget::new(file_range.file(), file_range.range())
             }
         })
         .collect()
@@ -323,53 +633,57 @@ pub(crate) fn find_goto_target(
         .find_first(|node| node.is_identifier() || node.is_expression())
         .ok()?;
 
-    tracing::trace!("Covering node is of kind {:?}", covering_node.node().kind());
-
-    match covering_node.node() {
-        AnyNodeRef::Identifier(identifier) => match covering_node.parent() {
-            Some(AnyNodeRef::StmtFunctionDef(function)) => Some(GotoTarget::FunctionDef(function)),
-            Some(AnyNodeRef::StmtClassDef(class)) => Some(GotoTarget::ClassDef(class)),
-            Some(AnyNodeRef::Parameter(parameter)) => Some(GotoTarget::Parameter(parameter)),
-            Some(AnyNodeRef::Alias(alias)) => Some(GotoTarget::Alias(alias)),
-            Some(AnyNodeRef::StmtImportFrom(from)) => Some(GotoTarget::ImportedModule(from)),
-            Some(AnyNodeRef::ExceptHandlerExceptHandler(handler)) => {
-                Some(GotoTarget::ExceptVariable(handler))
-            }
-            Some(AnyNodeRef::Keyword(keyword)) => Some(GotoTarget::KeywordArgument(keyword)),
-            Some(AnyNodeRef::PatternMatchMapping(mapping)) => {
-                Some(GotoTarget::PatternMatchRest(mapping))
-            }
-            Some(AnyNodeRef::PatternKeyword(keyword)) => {
-                Some(GotoTarget::PatternKeywordArgument(keyword))
-            }
-            Some(AnyNodeRef::PatternMatchStar(star)) => {
-                Some(GotoTarget::PatternMatchStarName(star))
-            }
-            Some(AnyNodeRef::PatternMatchAs(as_pattern)) => {
-                Some(GotoTarget::PatternMatchAsName(as_pattern))
-            }
-            Some(AnyNodeRef::TypeParamTypeVar(var)) => Some(GotoTarget::TypeParamTypeVarName(var)),
-            Some(AnyNodeRef::TypeParamParamSpec(bound)) => {
-                Some(GotoTarget::TypeParamParamSpecName(bound))
-            }
-            Some(AnyNodeRef::TypeParamTypeVarTuple(var_tuple)) => {
-                Some(GotoTarget::TypeParamTypeVarTupleName(var_tuple))
-            }
-            Some(AnyNodeRef::ExprAttribute(attribute)) => {
-                Some(GotoTarget::Expression(attribute.into()))
-            }
-            Some(AnyNodeRef::StmtNonlocal(_)) => Some(GotoTarget::NonLocal { identifier }),
-            Some(AnyNodeRef::StmtGlobal(_)) => Some(GotoTarget::Globals { identifier }),
-            None => None,
-            Some(parent) => {
-                tracing::debug!(
-                    "Missing `GoToTarget` for identifier with parent {:?}",
-                    parent.kind()
-                );
-                None
-            }
-        },
-
-        node => node.as_expr_ref().map(GotoTarget::Expression),
-    }
+    GotoTarget::from_covering_node(&covering_node, offset)
+}
+
+/// Helper function to resolve a module name and create a navigation target.
+fn resolve_module_to_navigation_target(
+    db: &dyn crate::Db,
+    module_name_str: &str,
+) -> Option<crate::NavigationTargets> {
+    use ty_python_semantic::{ModuleName, resolve_module};
+
+    if let Some(module_name) = ModuleName::new(module_name_str) {
+        if let Some(resolved_module) = resolve_module(db, &module_name) {
+            if let Some(module_file) = resolved_module.file(db) {
+                return Some(crate::NavigationTargets::single(
+                    crate::NavigationTarget::new(module_file, TextRange::default()),
+                ));
+            }
+        }
+    }
+    None
+}
+
+/// Helper function to extract module component information from a dotted module name
+fn find_module_component(
+    full_module_name: &str,
+    module_start: TextSize,
+    offset: TextSize,
+) -> Option<(usize, TextRange)> {
+    let pos_in_module = offset - module_start;
+    let pos_in_module = pos_in_module.to_usize();
+
+    // Split the module name into components and find which one contains the offset
+    let mut current_pos = 0;
+    let components: Vec<&str> = full_module_name.split('.').collect();
+
+    for (i, component) in components.iter().enumerate() {
+        let component_start = current_pos;
+        let component_end = current_pos + component.len();
+
+        // Check if the offset is within this component or at its right boundary
+        if pos_in_module >= component_start && pos_in_module <= component_end {
+            let component_range = TextRange::new(
+                module_start + TextSize::from(u32::try_from(component_start).ok()?),
+                module_start + TextSize::from(u32::try_from(component_end).ok()?),
+            );
+            return Some((i, component_range));
+        }
+
+        // Move past this component and the dot
+        current_pos = component_end + 1; // +1 for the dot
+    }
+
+    None
 }

crates/ty_ide/src/goto_declaration.rs

@@ -32,6 +32,7 @@ mod tests {
     use insta::assert_snapshot;
     use ruff_db::diagnostic::{
         Annotation, Diagnostic, DiagnosticId, LintName, Severity, Span, SubDiagnostic,
+        SubDiagnosticSeverity,
     };
     use ruff_db::files::FileRange;
     use ruff_text_size::Ranged;
@@ -610,6 +611,229 @@ def another_helper():
         "#);
     }
 
+    #[test]
+    fn goto_declaration_import_as_alias_name() {
+        let test = CursorTest::builder()
+            .source(
+                "main.py",
+                "
+import mymodule.submodule as su<CURSOR>b
+print(sub.helper())
+",
+            )
+            .source(
+                "mymodule/__init__.py",
+                "
+# Main module init
+",
+            )
+            .source(
+                "mymodule/submodule.py",
+                r#"
+FOO = 0
+"#,
+            )
+            .build();
+
+        assert_snapshot!(test.goto_declaration(), @r"
+        info[goto-declaration]: Declaration
+         --> mymodule/submodule.py:1:1
+          |
+        1 |
+          | ^
+        2 | FOO = 0
+          |
+        info: Source
+         --> main.py:2:30
+          |
+        2 | import mymodule.submodule as sub
+          |                              ^^^
+        3 | print(sub.helper())
+          |
+        ");
+    }
+
+    #[test]
+    fn goto_declaration_import_as_alias_name_on_module() {
+        let test = CursorTest::builder()
+            .source(
+                "main.py",
+                "
+import mymodule.submod<CURSOR>ule as sub
+print(sub.helper())
+",
+            )
+            .source(
+                "mymodule/__init__.py",
+                "
+# Main module init
+",
+            )
+            .source(
+                "mymodule/submodule.py",
+                r#"
+FOO = 0
+"#,
+            )
+            .build();
+
+        assert_snapshot!(test.goto_declaration(), @r"
+        info[goto-declaration]: Declaration
+         --> mymodule/submodule.py:1:1
+          |
+        1 |
+          | ^
+        2 | FOO = 0
+          |
+        info: Source
+         --> main.py:2:17
+          |
+        2 | import mymodule.submodule as sub
+          |                 ^^^^^^^^^
+        3 | print(sub.helper())
+          |
+        ");
+    }
+
+    #[test]
+    fn goto_declaration_from_import_symbol_original() {
+        let test = CursorTest::builder()
+            .source(
+                "main.py",
+                r#"
+from mypackage.utils import hel<CURSOR>per as h
+result = h("/a", "/b")
+"#,
+            )
+            .source(
+                "mypackage/__init__.py",
+                r#"
+# Package init
+"#,
+            )
+            .source(
+                "mypackage/utils.py",
+                r#"
+def helper(a, b):
+    return a + "/" + b
+
+def another_helper(path):
+    return "processed"
+"#,
+            )
+            .build();
+
+        assert_snapshot!(test.goto_declaration(), @r#"
+        info[goto-declaration]: Declaration
+         --> mypackage/utils.py:2:5
+          |
+        2 | def helper(a, b):
+          |     ^^^^^^
+        3 |     return a + "/" + b
+          |
+        info: Source
+         --> main.py:2:29
+          |
+        2 | from mypackage.utils import helper as h
+          |                             ^^^^^^
+        3 | result = h("/a", "/b")
+          |
+        "#);
+    }
+
+    #[test]
+    fn goto_declaration_from_import_symbol_alias() {
+        let test = CursorTest::builder()
+            .source(
+                "main.py",
+                r#"
+from mypackage.utils import helper as h<CURSOR>
+result = h("/a", "/b")
+"#,
+            )
+            .source(
+                "mypackage/__init__.py",
+                r#"
+# Package init
+"#,
+            )
+            .source(
+                "mypackage/utils.py",
+                r#"
+def helper(a, b):
+    return a + "/" + b
+
+def another_helper(path):
+    return "processed"
+"#,
+            )
+            .build();
+
+        assert_snapshot!(test.goto_declaration(), @r#"
+        info[goto-declaration]: Declaration
+         --> mypackage/utils.py:2:5
+          |
+        2 | def helper(a, b):
+          |     ^^^^^^
+        3 |     return a + "/" + b
+          |
+        info: Source
+         --> main.py:2:39
+          |
+        2 | from mypackage.utils import helper as h
+          |                                       ^
+        3 | result = h("/a", "/b")
+          |
+        "#);
+    }
+
+    #[test]
+    fn goto_declaration_from_import_module() {
+        let test = CursorTest::builder()
+            .source(
+                "main.py",
+                r#"
+from mypackage.ut<CURSOR>ils import helper as h
+result = h("/a", "/b")
+"#,
+            )
+            .source(
+                "mypackage/__init__.py",
+                r#"
+# Package init
+"#,
+            )
+            .source(
+                "mypackage/utils.py",
+                r#"
+def helper(a, b):
+    return a + "/" + b
+
+def another_helper(path):
+    return "processed"
+"#,
+            )
+            .build();
+
+        assert_snapshot!(test.goto_declaration(), @r#"
+        info[goto-declaration]: Declaration
+         --> mypackage/utils.py:1:1
+          |
+        1 |
+          | ^
+        2 | def helper(a, b):
+        3 |     return a + "/" + b
+          |
+        info: Source
+         --> main.py:2:16
+          |
+        2 | from mypackage.utils import helper as h
+          |                ^^^^^
+        3 | result = h("/a", "/b")
+          |
+        "#);
+    }
+
     #[test]
     fn goto_declaration_instance_attribute() {
         let test = cursor_test(
@@ -1126,7 +1350,7 @@ class MyClass:
 
     impl IntoDiagnostic for GotoDeclarationDiagnostic {
         fn into_diagnostic(self) -> Diagnostic {
-            let mut source = SubDiagnostic::new(Severity::Info, "Source");
+            let mut source = SubDiagnostic::new(SubDiagnosticSeverity::Info, "Source");
             source.annotate(Annotation::primary(
                 Span::from(self.source.file()).with_range(self.source.range()),
             ));

crates/ty_ide/src/goto_definition.rs

@@ -29,3 +29,569 @@ pub fn goto_definition(
         value: definition_targets,
     })
 }
+
+#[cfg(test)]
+mod test {
+    use crate::tests::{CursorTest, IntoDiagnostic};
+    use crate::{NavigationTarget, goto_definition};
+    use insta::assert_snapshot;
+    use ruff_db::diagnostic::{
+        Annotation, Diagnostic, DiagnosticId, LintName, Severity, Span, SubDiagnostic,
+        SubDiagnosticSeverity,
+    };
+    use ruff_db::files::FileRange;
+    use ruff_text_size::Ranged;
+
+    /// goto-definition on a module should go to the .py not the .pyi
+    ///
+    /// TODO: this currently doesn't work right! This is especially surprising
+    /// because [`goto_definition_stub_map_module_ref`] works fine.
+    #[test]
+    fn goto_definition_stub_map_module_import() {
+        let test = CursorTest::builder()
+            .source(
+                "main.py",
+                "
+from mymo<CURSOR>dule import my_function
+",
+            )
+            .source(
+                "mymodule.py",
+                r#"
+def my_function():
+    return "hello"
+"#,
+            )
+            .source(
+                "mymodule.pyi",
+                r#"
+def my_function(): ...
+"#,
+            )
+            .build();
+
+        assert_snapshot!(test.goto_definition(), @r"
+        info[goto-definition]: Definition
+         --> mymodule.pyi:1:1
+          |
+        1 |
+          | ^
+        2 | def my_function(): ...
+          |
+        info: Source
+         --> main.py:2:6
+          |
+        2 | from mymodule import my_function
+          |      ^^^^^^^^
+          |
+        ");
+    }
+
+    /// goto-definition on a module ref should go to the .py not the .pyi
+    #[test]
+    fn goto_definition_stub_map_module_ref() {
+        let test = CursorTest::builder()
+            .source(
+                "main.py",
+                "
+import mymodule
+x = mymo<CURSOR>dule
+",
+            )
+            .source(
+                "mymodule.py",
+                r#"
+def my_function():
+    return "hello"
+"#,
+            )
+            .source(
+                "mymodule.pyi",
+                r#"
+def my_function(): ...
+"#,
+            )
+            .build();
+
+        assert_snapshot!(test.goto_definition(), @r#"
+        info[goto-definition]: Definition
+         --> mymodule.py:1:1
+          |
+        1 |
+          | ^
+        2 | def my_function():
+        3 |     return "hello"
+          |
+        info: Source
+         --> main.py:3:5
+          |
+        2 | import mymodule
+        3 | x = mymodule
+          |     ^^^^^^^^
+          |
+        "#);
+    }
+
+    /// goto-definition on a function call should go to the .py not the .pyi
+    #[test]
+    fn goto_definition_stub_map_function() {
+        let test = CursorTest::builder()
+            .source(
+                "main.py",
+                "
+from mymodule import my_function
+print(my_func<CURSOR>tion())
+",
+            )
+            .source(
+                "mymodule.py",
+                r#"
+def my_function():
+    return "hello"
+
+def other_function():
+    return "other"
+"#,
+            )
+            .source(
+                "mymodule.pyi",
+                r#"
+def my_function(): ...
+
+def other_function(): ...
+"#,
+            )
+            .build();
+
+        assert_snapshot!(test.goto_definition(), @r#"
+        info[goto-definition]: Definition
+         --> mymodule.py:2:5
+          |
+        2 | def my_function():
+          |     ^^^^^^^^^^^
+        3 |     return "hello"
+          |
+        info: Source
+         --> main.py:3:7
+          |
+        2 | from mymodule import my_function
+        3 | print(my_function())
+          |       ^^^^^^^^^^^
+          |
+        "#);
+    }
+
+    /// goto-definition on a function that's redefined many times in the impl .py
+    ///
+    /// Currently this yields all instances. There's an argument for only yielding
+    /// the final one since that's the one "exported" but, this is consistent for
+    /// how we do file-local goto-definition.
+    #[test]
+    fn goto_definition_stub_map_function_redefine() {
+        let test = CursorTest::builder()
+            .source(
+                "main.py",
+                "
+from mymodule import my_function
+print(my_func<CURSOR>tion())
+",
+            )
+            .source(
+                "mymodule.py",
+                r#"
+def my_function():
+    return "hello"
+
+def my_function():
+    return "hello again"
+
+def my_function():
+    return "we can't keep doing this"
+
+def other_function():
+    return "other"
+"#,
+            )
+            .source(
+                "mymodule.pyi",
+                r#"
+def my_function(): ...
+
+def other_function(): ...
+"#,
+            )
+            .build();
+
+        assert_snapshot!(test.goto_definition(), @r#"
+        info[goto-definition]: Definition
+         --> mymodule.py:2:5
+          |
+        2 | def my_function():
+          |     ^^^^^^^^^^^
+        3 |     return "hello"
+          |
+        info: Source
+         --> main.py:3:7
+          |
+        2 | from mymodule import my_function
+        3 | print(my_function())
+          |       ^^^^^^^^^^^
+          |
+
+        info[goto-definition]: Definition
+         --> mymodule.py:5:5
+          |
+        3 |     return "hello"
+        4 |
+        5 | def my_function():
+          |     ^^^^^^^^^^^
+        6 |     return "hello again"
+          |
+        info: Source
+         --> main.py:3:7
+          |
+        2 | from mymodule import my_function
+        3 | print(my_function())
+          |       ^^^^^^^^^^^
+          |
+
+        info[goto-definition]: Definition
+         --> mymodule.py:8:5
+          |
+        6 |     return "hello again"
+        7 |
+        8 | def my_function():
+          |     ^^^^^^^^^^^
+        9 |     return "we can't keep doing this"
+          |
+        info: Source
+         --> main.py:3:7
+          |
+        2 | from mymodule import my_function
+        3 | print(my_function())
+          |       ^^^^^^^^^^^
+          |
+        "#);
+    }
+
+    /// goto-definition on a class ref go to the .py not the .pyi
+    #[test]
+    fn goto_definition_stub_map_class_ref() {
+        let test = CursorTest::builder()
+            .source(
+                "main.py",
+                "
+from mymodule import MyClass
+x = MyC<CURSOR>lass
+",
+            )
+            .source(
+                "mymodule.py",
+                r#"
+class MyClass:
+    def __init__(self, val):
+        self.val = val
+
+class MyOtherClass:
+    def __init__(self, val):
+        self.val = val + 1
+"#,
+            )
+            .source(
+                "mymodule.pyi",
+                r#"
+class MyClass:
+    def __init__(self, val: bool): ...
+
+class MyOtherClass:
+    def __init__(self, val: bool): ...
+"#,
+            )
+            .build();
+
+        assert_snapshot!(test.goto_definition(), @r"
+        info[goto-definition]: Definition
+         --> mymodule.py:2:7
+          |
+        2 | class MyClass:
+          |       ^^^^^^^
+        3 |     def __init__(self, val):
+        4 |         self.val = val
+          |
+        info: Source
+         --> main.py:3:5
+          |
+        2 | from mymodule import MyClass
+        3 | x = MyClass
+          |     ^^^^^^^
+          |
+        ");
+    }
+
+    /// goto-definition on a class init should go to the .py not the .pyi
+    #[test]
+    fn goto_definition_stub_map_class_init() {
+        let test = CursorTest::builder()
+            .source(
+                "main.py",
+                "
+from mymodule import MyClass
+x = MyCl<CURSOR>ass(0)
+",
+            )
+            .source(
+                "mymodule.py",
+                r#"
+class MyClass:
+    def __init__(self, val):
+        self.val = val
+
+class MyOtherClass:
+    def __init__(self, val):
+        self.val = val + 1
+"#,
+            )
+            .source(
+                "mymodule.pyi",
+                r#"
+class MyClass:
+    def __init__(self, val: bool): ...
+
+class MyOtherClass:
+    def __init__(self, val: bool): ...
+"#,
+            )
+            .build();
+
+        assert_snapshot!(test.goto_definition(), @r"
+        info[goto-definition]: Definition
+         --> mymodule.py:2:7
+          |
+        2 | class MyClass:
+          |       ^^^^^^^
+        3 |     def __init__(self, val):
+        4 |         self.val = val
+          |
+        info: Source
+         --> main.py:3:5
+          |
+        2 | from mymodule import MyClass
+        3 | x = MyClass(0)
+          |     ^^^^^^^
+          |
+        ");
+    }
+
+    /// goto-definition on a class method should go to the .py not the .pyi
+    #[test]
+    fn goto_definition_stub_map_class_method() {
+        let test = CursorTest::builder()
+            .source(
+                "main.py",
+                "
+from mymodule import MyClass
+x = MyClass(0)
+x.act<CURSOR>ion()
+",
+            )
+            .source(
+                "mymodule.py",
+                r#"
+class MyClass:
+    def __init__(self, val):
+        self.val = val
+    def action(self):
+        print(self.val)
+
+class MyOtherClass:
+    def __init__(self, val):
+        self.val = val + 1
+"#,
+            )
+            .source(
+                "mymodule.pyi",
+                r#"
+class MyClass:
+    def __init__(self, val: bool): ...
+    def action(self): ...
+
+class MyOtherClass:
+    def __init__(self, val: bool): ...
+"#,
+            )
+            .build();
+
+        assert_snapshot!(test.goto_definition(), @r"
+        info[goto-definition]: Definition
+         --> mymodule.py:5:9
+          |
+        3 |     def __init__(self, val):
+        4 |         self.val = val
+        5 |     def action(self):
+          |         ^^^^^^
+        6 |         print(self.val)
+          |
+        info: Source
+         --> main.py:4:1
+          |
+        2 | from mymodule import MyClass
+        3 | x = MyClass(0)
+        4 | x.action()
+          | ^^^^^^^^
+          |
+        ");
+    }
+
+    /// goto-definition on a class function should go to the .py not the .pyi
+    #[test]
+    fn goto_definition_stub_map_class_function() {
+        let test = CursorTest::builder()
+            .source(
+                "main.py",
+                "
+from mymodule import MyClass
+x = MyClass.act<CURSOR>ion()
+",
+            )
+            .source(
+                "mymodule.py",
+                r#"
+class MyClass:
+    def __init__(self, val):
+        self.val = val
+    def action():
+        print("hi!")
+
+class MyOtherClass:
+    def __init__(self, val):
+        self.val = val + 1
+"#,
+            )
+            .source(
+                "mymodule.pyi",
+                r#"
+class MyClass:
+    def __init__(self, val: bool): ...
+    def action(): ...
+
+class MyOtherClass:
+    def __init__(self, val: bool): ...
+"#,
+            )
+            .build();
+
+        assert_snapshot!(test.goto_definition(), @r#"
+        info[goto-definition]: Definition
+         --> mymodule.py:5:9
+          |
+        3 |     def __init__(self, val):
+        4 |         self.val = val
+        5 |     def action():
+          |         ^^^^^^
+        6 |         print("hi!")
+          |
+        info: Source
+         --> main.py:3:5
+          |
+        2 | from mymodule import MyClass
+        3 | x = MyClass.action()
+          |     ^^^^^^^^^^^^^^
+          |
+        "#);
+    }
+
+    /// goto-definition on a class import should go to the .py not the .pyi
+    #[test]
+    fn goto_definition_stub_map_class_import() {
+        let test = CursorTest::builder()
+            .source(
+                "main.py",
+                "
+from mymodule import MyC<CURSOR>lass
+",
+            )
+            .source(
+                "mymodule.py",
+                r#"
+class MyClass: ...
+"#,
+            )
+            .source(
+                "mymodule.pyi",
+                r#"
+class MyClass: ...
+"#,
+            )
+            .build();
+
+        assert_snapshot!(test.goto_definition(), @r"
+        info[goto-definition]: Definition
+         --> mymodule.py:2:7
+          |
+        2 | class MyClass: ...
+          |       ^^^^^^^
+          |
+        info: Source
+         --> main.py:2:22
+          |
+        2 | from mymodule import MyClass
+          |                      ^^^^^^^
+          |
+        ");
+    }
+
+    impl CursorTest {
+        fn goto_definition(&self) -> String {
+            let Some(targets) = goto_definition(&self.db, self.cursor.file, self.cursor.offset)
+            else {
+                return "No goto target found".to_string();
+            };
+
+            if targets.is_empty() {
+                return "No definitions found".to_string();
+            }
+
+            let source = targets.range;
+            self.render_diagnostics(
+                targets
+                    .into_iter()
+                    .map(|target| GotoDefinitionDiagnostic::new(source, &target)),
+            )
+        }
+    }
+
+    struct GotoDefinitionDiagnostic {
+        source: FileRange,
+        target: FileRange,
+    }
+
+    impl GotoDefinitionDiagnostic {
+        fn new(source: FileRange, target: &NavigationTarget) -> Self {
+            Self {
+                source,
+                target: FileRange::new(target.file(), target.focus_range()),
+            }
+        }
+    }
+
+    impl IntoDiagnostic for GotoDefinitionDiagnostic {
+        fn into_diagnostic(self) -> Diagnostic {
+            let mut source = SubDiagnostic::new(SubDiagnosticSeverity::Info, "Source");
+            source.annotate(Annotation::primary(
+                Span::from(self.source.file()).with_range(self.source.range()),
+            ));
+
+            let mut main = Diagnostic::new(
+                DiagnosticId::Lint(LintName::of("goto-definition")),
+                Severity::Info,
+                "Definition".to_string(),
+            );
+            main.annotate(Annotation::primary(
+                Span::from(self.target.file()).with_range(self.target.range()),
+            ));
+            main.sub(source);
+
+            main
+        }
+    }
+}

crates/ty_ide/src/goto_type_definition.rs

@@ -33,6 +33,7 @@ mod tests {
     use insta::assert_snapshot;
     use ruff_db::diagnostic::{
         Annotation, Diagnostic, DiagnosticId, LintName, Severity, Span, SubDiagnostic,
+        SubDiagnosticSeverity,
     };
     use ruff_db::files::FileRange;
     use ruff_text_size::Ranged;
@@ -198,14 +199,14 @@ mod tests {
 
         assert_snapshot!(test.goto_type_definition(), @r#"
         info[goto-type-definition]: Type definition
-           --> stdlib/builtins.pyi:892:7
+           --> stdlib/builtins.pyi:890:7
             |
-        890 |     def __getitem__(self, key: int, /) -> str | int | None: ...
-        891 |
-        892 | class str(Sequence[str]):
+        888 |     def __getitem__(self, key: int, /) -> str | int | None: ...
+        889 |
+        890 | class str(Sequence[str]):
             |       ^^^
-        893 |     """str(object='') -> str
-        894 |     str(bytes_or_buffer[, encoding[, errors]]) -> str
+        891 |     """str(object='') -> str
+        892 |     str(bytes_or_buffer[, encoding[, errors]]) -> str
             |
         info: Source
          --> main.py:4:13
@@ -227,14 +228,14 @@ mod tests {
 
         assert_snapshot!(test.goto_type_definition(), @r#"
         info[goto-type-definition]: Type definition
-           --> stdlib/builtins.pyi:892:7
+           --> stdlib/builtins.pyi:890:7
             |
-        890 |     def __getitem__(self, key: int, /) -> str | int | None: ...
-        891 |
-        892 | class str(Sequence[str]):
+        888 |     def __getitem__(self, key: int, /) -> str | int | None: ...
+        889 |
+        890 | class str(Sequence[str]):
             |       ^^^
-        893 |     """str(object='') -> str
-        894 |     str(bytes_or_buffer[, encoding[, errors]]) -> str
+        891 |     """str(object='') -> str
+        892 |     str(bytes_or_buffer[, encoding[, errors]]) -> str
             |
         info: Source
          --> main.py:2:22
@@ -343,14 +344,14 @@ mod tests {
 
         assert_snapshot!(test.goto_type_definition(), @r#"
         info[goto-type-definition]: Type definition
-           --> stdlib/builtins.pyi:892:7
+           --> stdlib/builtins.pyi:890:7
             |
-        890 |     def __getitem__(self, key: int, /) -> str | int | None: ...
-        891 |
-        892 | class str(Sequence[str]):
+        888 |     def __getitem__(self, key: int, /) -> str | int | None: ...
+        889 |
+        890 | class str(Sequence[str]):
             |       ^^^
-        893 |     """str(object='') -> str
-        894 |     str(bytes_or_buffer[, encoding[, errors]]) -> str
+        891 |     """str(object='') -> str
+        892 |     str(bytes_or_buffer[, encoding[, errors]]) -> str
             |
         info: Source
          --> main.py:4:18
@@ -378,14 +379,14 @@ mod tests {
         //   is an int. Navigating to `str` would match pyright's behavior.
         assert_snapshot!(test.goto_type_definition(), @r#"
         info[goto-type-definition]: Type definition
-           --> stdlib/builtins.pyi:338:7
+           --> stdlib/builtins.pyi:337:7
             |
-        336 | _LiteralInteger = _PositiveInteger | _NegativeInteger | Literal[0]  # noqa: Y026  # TODO: Use TypeAlias once mypy bugs are fixed
-        337 |
-        338 | class int:
+        335 | _LiteralInteger = _PositiveInteger | _NegativeInteger | Literal[0]  # noqa: Y026  # TODO: Use TypeAlias once mypy bugs are fixed
+        336 |
+        337 | class int:
             |       ^^^
-        339 |     """int([x]) -> integer
-        340 |     int(x, base=10) -> integer
+        338 |     """int([x]) -> integer
+        339 |     int(x, base=10) -> integer
             |
         info: Source
          --> main.py:4:18
@@ -412,14 +413,14 @@ f(**kwargs<CURSOR>)
 
         assert_snapshot!(test.goto_type_definition(), @r#"
         info[goto-type-definition]: Type definition
-            --> stdlib/builtins.pyi:2892:7
+            --> stdlib/builtins.pyi:2888:7
              |
-        2890 |         """See PEP 585"""
-        2891 |
-        2892 | class dict(MutableMapping[_KT, _VT]):
+        2886 |         """See PEP 585"""
+        2887 |
+        2888 | class dict(MutableMapping[_KT, _VT]):
              |       ^^^^
-        2893 |     """dict() -> new empty dictionary
-        2894 |     dict(mapping) -> new dictionary initialized from a mapping object's
+        2889 |     """dict() -> new empty dictionary
+        2890 |     dict(mapping) -> new dictionary initialized from a mapping object's
              |
         info: Source
          --> main.py:6:5
@@ -443,14 +444,14 @@ f(**kwargs<CURSOR>)
 
         assert_snapshot!(test.goto_type_definition(), @r#"
         info[goto-type-definition]: Type definition
-           --> stdlib/builtins.pyi:892:7
+           --> stdlib/builtins.pyi:890:7
             |
-        890 |     def __getitem__(self, key: int, /) -> str | int | None: ...
-        891 |
-        892 | class str(Sequence[str]):
+        888 |     def __getitem__(self, key: int, /) -> str | int | None: ...
+        889 |
+        890 | class str(Sequence[str]):
             |       ^^^
-        893 |     """str(object='') -> str
-        894 |     str(bytes_or_buffer[, encoding[, errors]]) -> str
+        891 |     """str(object='') -> str
+        892 |     str(bytes_or_buffer[, encoding[, errors]]) -> str
             |
         info: Source
          --> main.py:3:17
@@ -536,14 +537,14 @@ f(**kwargs<CURSOR>)
 
         assert_snapshot!(test.goto_type_definition(), @r#"
         info[goto-type-definition]: Type definition
-           --> stdlib/builtins.pyi:892:7
+           --> stdlib/builtins.pyi:890:7
             |
-        890 |     def __getitem__(self, key: int, /) -> str | int | None: ...
-        891 |
-        892 | class str(Sequence[str]):
+        888 |     def __getitem__(self, key: int, /) -> str | int | None: ...
+        889 |
+        890 | class str(Sequence[str]):
             |       ^^^
-        893 |     """str(object='') -> str
-        894 |     str(bytes_or_buffer[, encoding[, errors]]) -> str
+        891 |     """str(object='') -> str
+        892 |     str(bytes_or_buffer[, encoding[, errors]]) -> str
             |
         info: Source
          --> main.py:4:27
@@ -567,13 +568,13 @@ f(**kwargs<CURSOR>)
 
         assert_snapshot!(test.goto_type_definition(), @r#"
         info[goto-type-definition]: Type definition
-           --> stdlib/types.pyi:922:11
+           --> stdlib/types.pyi:921:11
             |
-        920 | if sys.version_info >= (3, 10):
-        921 |     @final
-        922 |     class NoneType:
+        919 | if sys.version_info >= (3, 10):
+        920 |     @final
+        921 |     class NoneType:
             |           ^^^^^^^^
-        923 |         """The type of the None singleton."""
+        922 |         """The type of the None singleton."""
             |
         info: Source
          --> main.py:3:17
@@ -584,14 +585,14 @@ f(**kwargs<CURSOR>)
           |
 
         info[goto-type-definition]: Type definition
-           --> stdlib/builtins.pyi:892:7
+           --> stdlib/builtins.pyi:890:7
             |
-        890 |     def __getitem__(self, key: int, /) -> str | int | None: ...
-        891 |
-        892 | class str(Sequence[str]):
+        888 |     def __getitem__(self, key: int, /) -> str | int | None: ...
+        889 |
+        890 | class str(Sequence[str]):
             |       ^^^
-        893 |     """str(object='') -> str
-        894 |     str(bytes_or_buffer[, encoding[, errors]]) -> str
+        891 |     """str(object='') -> str
+        892 |     str(bytes_or_buffer[, encoding[, errors]]) -> str
             |
         info: Source
          --> main.py:3:17
@@ -640,7 +641,7 @@ f(**kwargs<CURSOR>)
 
     impl IntoDiagnostic for GotoTypeDefinitionDiagnostic {
         fn into_diagnostic(self) -> Diagnostic {
-            let mut source = SubDiagnostic::new(Severity::Info, "Source");
+            let mut source = SubDiagnostic::new(SubDiagnosticSeverity::Info, "Source");
             source.annotate(Annotation::primary(
                 Span::from(self.source.file()).with_range(self.source.range()),
             ));

crates/ty_ide/src/inlay_hints.rs

@@ -156,9 +156,8 @@ mod tests {
     };
     use ruff_text_size::TextSize;
 
-    use crate::db::tests::TestDb;
-
     use ruff_db::system::{DbWithWritableSystem, SystemPathBuf};
+    use ty_project::ProjectMetadata;
     use ty_python_semantic::{
         Program, ProgramSettings, PythonPlatform, PythonVersionWithSource, SearchPathSettings,
     };
@@ -167,7 +166,10 @@ mod tests {
         const START: &str = "<START>";
         const END: &str = "<END>";
 
-        let mut db = TestDb::new();
+        let mut db = ty_project::TestDb::new(ProjectMetadata::new(
+            "test".into(),
+            SystemPathBuf::from("/"),
+        ));
 
         let start = source.find(START);
         let end = source
@@ -205,7 +207,7 @@ mod tests {
     }
 
     pub(super) struct InlayHintTest {
-        pub(super) db: TestDb,
+        pub(super) db: ty_project::TestDb,
         pub(super) file: File,
         pub(super) range: TextRange,
     }

crates/ty_ide/src/lib.rs

@@ -1,5 +1,4 @@
 mod completion;
-mod db;
 mod docstring;
 mod find_node;
 mod goto;
@@ -9,17 +8,18 @@ mod goto_type_definition;
 mod hover;
 mod inlay_hints;
 mod markup;
+mod references;
 mod semantic_tokens;
 mod signature_help;
 mod stub_mapping;
 
 pub use completion::completion;
-pub use db::Db;
 pub use docstring::get_parameter_documentation;
 pub use goto::{goto_declaration, goto_definition, goto_type_definition};
 pub use hover::hover;
 pub use inlay_hints::inlay_hints;
 pub use markup::MarkupKind;
+pub use references::references;
 pub use semantic_tokens::{
     SemanticToken, SemanticTokenModifier, SemanticTokenType, SemanticTokens, semantic_tokens,
 };
@@ -29,6 +29,7 @@ use ruff_db::files::{File, FileRange};
 use ruff_text_size::{Ranged, TextRange};
 use rustc_hash::FxHashSet;
 use std::ops::{Deref, DerefMut};
+use ty_project::Db;
 use ty_python_semantic::types::{Type, TypeDefinition};
 
 /// Information associated with a text range.
@@ -87,6 +88,15 @@ pub struct NavigationTarget {
 }
 
 impl NavigationTarget {
+    /// Creates a new `NavigationTarget` where the focus and full range are identical.
+    pub fn new(file: File, range: TextRange) -> Self {
+        Self {
+            file,
+            focus_range: range,
+            full_range: range,
+        }
+    }
+
     pub fn file(&self) -> File {
         self.file
     }
@@ -211,13 +221,13 @@ impl HasNavigationTargets for TypeDefinition<'_> {
 
 #[cfg(test)]
 mod tests {
-    use crate::db::tests::TestDb;
     use insta::internals::SettingsBindDropGuard;
     use ruff_db::Db;
     use ruff_db::diagnostic::{Diagnostic, DiagnosticFormat, DisplayDiagnosticConfig};
     use ruff_db::files::{File, system_path_to_file};
     use ruff_db::system::{DbWithWritableSystem, SystemPath, SystemPathBuf};
     use ruff_text_size::TextSize;
+    use ty_project::ProjectMetadata;
     use ty_python_semantic::{
         Program, ProgramSettings, PythonPlatform, PythonVersionWithSource, SearchPathSettings,
     };
@@ -231,7 +241,7 @@ mod tests {
     }
 
     pub(super) struct CursorTest {
-        pub(super) db: TestDb,
+        pub(super) db: ty_project::TestDb,
         pub(super) cursor: Cursor,
         _insta_settings_guard: SettingsBindDropGuard,
     }
@@ -286,8 +296,13 @@ mod tests {
 
     impl CursorTestBuilder {
         pub(super) fn build(&self) -> CursorTest {
-            let mut db = TestDb::new();
+            let mut db = ty_project::TestDb::new(ProjectMetadata::new(
+                "test".into(),
+                SystemPathBuf::from("/"),
+            ));
+
             let mut cursor: Option<Cursor> = None;
+
             for &Source {
                 ref path,
                 ref contents,
@@ -296,19 +311,19 @@ mod tests {
             {
                 db.write_file(path, contents)
                     .expect("write to memory file system to be successful");
-                let Some(offset) = cursor_offset else {
-                    continue;
-                };
 
                 let file = system_path_to_file(&db, path).expect("newly written file to existing");
-                // This assert should generally never trip, since
-                // we have an assert on `CursorTestBuilder::source`
-                // to ensure we never have more than one marker.
-                assert!(
-                    cursor.is_none(),
-                    "found more than one source that contains `<CURSOR>`"
-                );
-                cursor = Some(Cursor { file, offset });
+
+                if let Some(offset) = cursor_offset {
+                    // This assert should generally never trip, since
+                    // we have an assert on `CursorTestBuilder::source`
+                    // to ensure we never have more than one marker.
+                    assert!(
+                        cursor.is_none(),
+                        "found more than one source that contains `<CURSOR>`"
+                    );
+                    cursor = Some(Cursor { file, offset });
+                }
             }
 
             let search_paths = SearchPathSettings::new(vec![SystemPathBuf::from("/")])

crates/ty_ide/src/semantic_tokens.rs

@@ -664,6 +664,26 @@ impl SourceOrderVisitor<'_> for SemanticTokenVisitor<'_> {
                     }
                 }
             }
+            ast::Stmt::Nonlocal(nonlocal_stmt) => {
+                // Handle nonlocal statements - classify identifiers as variables
+                for identifier in &nonlocal_stmt.names {
+                    self.add_token(
+                        identifier.range(),
+                        SemanticTokenType::Variable,
+                        SemanticTokenModifier::empty(),
+                    );
+                }
+            }
+            ast::Stmt::Global(global_stmt) => {
+                // Handle global statements - classify identifiers as variables
+                for identifier in &global_stmt.names {
+                    self.add_token(
+                        identifier.range(),
+                        SemanticTokenType::Variable,
+                        SemanticTokenModifier::empty(),
+                    );
+                }
+            }
             _ => {
                 // For all other statement types, let the default visitor handle them
                 walk_stmt(self, stmt);
@@ -831,6 +851,71 @@ impl SourceOrderVisitor<'_> for SemanticTokenVisitor<'_> {
             }
         }
     }
+
+    fn visit_except_handler(&mut self, except_handler: &ast::ExceptHandler) {
+        match except_handler {
+            ast::ExceptHandler::ExceptHandler(handler) => {
+                // Visit the exception type expression if present
+                if let Some(type_expr) = &handler.type_ {
+                    self.visit_expr(type_expr);
+                }
+
+                // Handle the exception variable name (after "as")
+                if let Some(name) = &handler.name {
+                    self.add_token(
+                        name.range(),
+                        SemanticTokenType::Variable,
+                        SemanticTokenModifier::empty(),
+                    );
+                }
+
+                // Visit the handler body
+                self.visit_body(&handler.body);
+            }
+        }
+    }
+
+    fn visit_pattern(&mut self, pattern: &ast::Pattern) {
+        match pattern {
+            ast::Pattern::MatchAs(pattern_as) => {
+                // Visit the nested pattern first to maintain source order
+                if let Some(nested_pattern) = &pattern_as.pattern {
+                    self.visit_pattern(nested_pattern);
+                }
+
+                // Now add the "as" variable name token
+                if let Some(name) = &pattern_as.name {
+                    self.add_token(
+                        name.range(),
+                        SemanticTokenType::Variable,
+                        SemanticTokenModifier::empty(),
+                    );
+                }
+            }
+            ast::Pattern::MatchMapping(pattern_mapping) => {
+                // Visit keys and patterns in source order by interleaving them
+                for (key, nested_pattern) in
+                    pattern_mapping.keys.iter().zip(&pattern_mapping.patterns)
+                {
+                    self.visit_expr(key);
+                    self.visit_pattern(nested_pattern);
+                }
+
+                // Handle the rest parameter (after "**") - this comes last
+                if let Some(rest_name) = &pattern_mapping.rest {
+                    self.add_token(
+                        rest_name.range(),
+                        SemanticTokenType::Variable,
+                        SemanticTokenModifier::empty(),
+                    );
+                }
+            }
+            _ => {
+                // For all other pattern types, use the default walker
+                ruff_python_ast::visitor::source_order::walk_pattern(self, pattern);
+            }
+        }
+    }
 }
 
 #[cfg(test)]
@@ -1942,4 +2027,200 @@ complex_fstring = f"User: {name.upper()}, Count: {len(data)}, Hex: {value:x}"<CU
         "x" @ 414..415: String
         "#);
     }
+
+    #[test]
+    fn test_nonlocal_and_global_statements() {
+        let test = cursor_test(
+            r#"
+x = "global_value"
+y = "another_global"
+
+def outer():
+    x = "outer_value"
+    z = "outer_local"
+    
+    def inner():
+        nonlocal x, z  # These should be variable tokens
+        global y       # This should be a variable token
+        x = "modified"
+        y = "modified_global"
+        z = "modified_local"
+        
+        def deeper():
+            nonlocal x    # Variable token
+            global y, x   # Both should be variable tokens
+            return x + y
+        
+        return deeper
+    
+    return inner<CURSOR>
+"#,
+        );
+
+        let tokens = semantic_tokens_full_file(&test.db, test.cursor.file);
+
+        assert_snapshot!(semantic_tokens_to_snapshot(&test.db, test.cursor.file, &tokens), @r#"
+        "x" @ 1..2: Variable
+        "/"global_value/"" @ 5..19: String
+        "y" @ 20..21: Variable
+        "/"another_global/"" @ 24..40: String
+        "outer" @ 46..51: Function [definition]
+        "x" @ 59..60: Variable
+        "/"outer_value/"" @ 63..76: String
+        "z" @ 81..82: Variable
+        "/"outer_local/"" @ 85..98: String
+        "inner" @ 112..117: Function [definition]
+        "x" @ 138..139: Variable
+        "z" @ 141..142: Variable
+        "y" @ 193..194: Variable
+        "x" @ 243..244: Variable
+        "/"modified/"" @ 247..257: String
+        "y" @ 266..267: Variable
+        "/"modified_global/"" @ 270..287: String
+        "z" @ 296..297: Variable
+        "/"modified_local/"" @ 300..316: String
+        "deeper" @ 338..344: Function [definition]
+        "x" @ 369..370: Variable
+        "y" @ 410..411: Variable
+        "x" @ 413..414: Variable
+        "x" @ 469..470: Variable
+        "y" @ 473..474: Variable
+        "deeper" @ 499..505: Function
+        "inner" @ 522..527: Function
+        "#);
+    }
+
+    #[test]
+    fn test_nonlocal_global_edge_cases() {
+        let test = cursor_test(
+            r#"
+# Single variable statements
+def test():
+    global x
+    nonlocal y
+    
+    # Multiple variables in one statement
+    global a, b, c
+    nonlocal d, e, f
+    
+    return x + y + a + b + c + d + e + f<CURSOR>
+"#,
+        );
+
+        let tokens = semantic_tokens_full_file(&test.db, test.cursor.file);
+
+        assert_snapshot!(semantic_tokens_to_snapshot(&test.db, test.cursor.file, &tokens), @r#"
+        "test" @ 34..38: Function [definition]
+        "x" @ 53..54: Variable
+        "y" @ 68..69: Variable
+        "a" @ 128..129: Variable
+        "b" @ 131..132: Variable
+        "c" @ 134..135: Variable
+        "d" @ 149..150: Variable
+        "e" @ 152..153: Variable
+        "f" @ 155..156: Variable
+        "x" @ 173..174: Variable
+        "y" @ 177..178: Variable
+        "a" @ 181..182: Variable
+        "b" @ 185..186: Variable
+        "c" @ 189..190: Variable
+        "d" @ 193..194: Variable
+        "e" @ 197..198: Variable
+        "f" @ 201..202: Variable
+        "#);
+    }
+
+    #[test]
+    fn test_pattern_matching() {
+        let test = cursor_test(
+            r#"
+def process_data(data):
+    match data:
+        case {"name": name, "age": age, **rest} as person:
+            print(f"Person {name}, age {age}, extra: {rest}")
+            return person
+        case [first, *remaining] as sequence:
+            print(f"First: {first}, remaining: {remaining}")
+            return sequence
+        case value as fallback:
+            print(f"Fallback: {fallback}")
+            return fallback<CURSOR>
+"#,
+        );
+
+        let tokens = semantic_tokens_full_file(&test.db, test.cursor.file);
+
+        assert_snapshot!(semantic_tokens_to_snapshot(&test.db, test.cursor.file, &tokens), @r#"
+        "process_data" @ 5..17: Function [definition]
+        "data" @ 18..22: Parameter
+        "data" @ 35..39: Variable
+        "/"name/"" @ 55..61: String
+        "name" @ 63..67: Variable
+        "/"age/"" @ 69..74: String
+        "age" @ 76..79: Variable
+        "rest" @ 83..87: Variable
+        "person" @ 92..98: Variable
+        "print" @ 112..117: Function
+        "Person " @ 120..127: String
+        "name" @ 128..132: Variable
+        ", age " @ 133..139: String
+        "age" @ 140..143: Variable
+        ", extra: " @ 144..153: String
+        "rest" @ 154..158: Variable
+        "person" @ 181..187: Variable
+        "first" @ 202..207: Variable
+        "sequence" @ 224..232: Variable
+        "print" @ 246..251: Function
+        "First: " @ 254..261: String
+        "first" @ 262..267: Variable
+        ", remaining: " @ 268..281: String
+        "remaining" @ 282..291: Variable
+        "sequence" @ 314..322: Variable
+        "value" @ 336..341: Variable
+        "fallback" @ 345..353: Variable
+        "print" @ 367..372: Function
+        "Fallback: " @ 375..385: String
+        "fallback" @ 386..394: Variable
+        "fallback" @ 417..425: Variable
+        "#);
+    }
+
+    #[test]
+    fn test_exception_handlers() {
+        let test = cursor_test(
+            r#"
+try:
+    x = 1 / 0
+except ValueError as ve:
+    print(ve)
+except (TypeError, RuntimeError) as re:
+    print(re)
+except Exception as e:
+    print(e)
+finally:
+    pass<CURSOR>
+"#,
+        );
+
+        let tokens = semantic_tokens_full_file(&test.db, test.cursor.file);
+
+        assert_snapshot!(semantic_tokens_to_snapshot(&test.db, test.cursor.file, &tokens), @r#"
+        "x" @ 10..11: Variable
+        "1" @ 14..15: Number
+        "0" @ 18..19: Number
+        "ValueError" @ 27..37: Class
+        "ve" @ 41..43: Variable
+        "print" @ 49..54: Function
+        "ve" @ 55..57: Variable
+        "TypeError" @ 67..76: Class
+        "RuntimeError" @ 78..90: Class
+        "re" @ 95..97: Variable
+        "print" @ 103..108: Function
+        "re" @ 109..111: Variable
+        "Exception" @ 120..129: Class
+        "e" @ 133..134: Variable
+        "print" @ 140..145: Function
+        "e" @ 146..147: Variable
+        "#);
+    }
 }