convert to serializable diagnostics

This reverts commit e1219bc27c.

.github/workflows/ci.yaml

@@ -143,12 +143,12 @@ jobs:
         env:
           MERGE_BASE: ${{ steps.merge_base.outputs.sha }}
         run: |
-          # NOTE: Do not exclude all Markdown files here, but rather use
-          # specific exclude patterns like 'docs/**'), because tests for
-          # 'ty' are written in Markdown.
-          if git diff --quiet "${MERGE_BASE}...HEAD" -- \
+          if git diff --quiet "${MERGE_BASE}...HEAD" -- ':**' \
+            ':!**/*.md' \
+            ':crates/ty_python_semantic/resources/mdtest/**/*.md' \
             ':!docs/**' \
             ':!assets/**' \
+            ':.github/workflows/ci.yaml' \
           ; then
               echo "changed=false" >> "$GITHUB_OUTPUT"
           else

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

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

.github/workflows/typing_conformance_comment.yaml

@@ -1,97 +0,0 @@
-name: PR comment (typing_conformance)
-
-on: # zizmor: ignore[dangerous-triggers]
-  workflow_run:
-    workflows: [Run typing conformance]
-    types: [completed]
-  workflow_dispatch:
-    inputs:
-      workflow_run_id:
-        description: The typing_conformance workflow that triggers the workflow run
-        required: true
-
-jobs:
-  comment:
-    runs-on: ubuntu-24.04
-    permissions:
-      pull-requests: write
-    steps:
-      - uses: dawidd6/action-download-artifact@20319c5641d495c8a52e688b7dc5fada6c3a9fbc # v8
-        name: Download PR number
-        with:
-          name: pr-number
-          run_id: ${{ github.event.workflow_run.id ||  github.event.inputs.workflow_run_id }}
-          if_no_artifact_found: ignore
-          allow_forks: true
-
-      - name: Parse pull request number
-        id: pr-number
-        run: |
-          if [[ -f pr-number ]]
-          then
-            echo "pr-number=$(<pr-number)" >> "$GITHUB_OUTPUT"
-          fi
-
-      - uses: dawidd6/action-download-artifact@20319c5641d495c8a52e688b7dc5fada6c3a9fbc # v8
-        name: "Download typing_conformance results"
-        id: download-typing_conformance_diff
-        if: steps.pr-number.outputs.pr-number
-        with:
-          name: typing_conformance_diagnostics_diff
-          workflow: typing_conformance.yaml
-          pr: ${{ steps.pr-number.outputs.pr-number }}
-          path: pr/typing_conformance_diagnostics_diff
-          workflow_conclusion: completed
-          if_no_artifact_found: ignore
-          allow_forks: true
-
-      - name: Generate comment content
-        id: generate-comment
-        if: ${{ steps.download-typing_conformance_diff.outputs.found_artifact == 'true' }}
-        run: |
-          # Guard against malicious typing_conformance results that symlink to a secret
-          # file on this runner
-          if [[ -L pr/typing_conformance_diagnostics_diff/typing_conformance_diagnostics.diff ]]
-          then
-              echo "Error: typing_conformance_diagnostics.diff cannot be a symlink"
-              exit 1
-          fi
-
-          # Note this identifier is used to find the comment to update on
-          # subsequent runs
-          echo '<!-- generated-comment typing_conformance_diagnostics_diff -->' >> comment.txt
-
-          echo '## Diagnostic diff on typing conformance tests' >> comment.txt
-          if [ -s "pr/typing_conformance_diagnostics_diff/typing_conformance_diagnostics.diff" ]; then
-            echo '<details>' >> comment.txt
-            echo '<summary>Changes were detected when running ty on typing conformance tests</summary>' >> comment.txt
-            echo '' >> comment.txt
-            echo '```diff' >> comment.txt
-            cat pr/typing_conformance_diagnostics_diff/typing_conformance_diagnostics.diff >> comment.txt
-            echo '```' >> comment.txt
-            echo '</details>' >> comment.txt
-          else
-            echo 'No changes detected when running ty on typing conformance tests ✅' >> comment.txt
-          fi
-
-          echo 'comment<<EOF' >> "$GITHUB_OUTPUT"
-          cat comment.txt >> "$GITHUB_OUTPUT"
-          echo 'EOF' >> "$GITHUB_OUTPUT"
-
-      - name: Find existing comment
-        uses: peter-evans/find-comment@3eae4d37986fb5a8592848f6a574fdf654e61f9e # v3.1.0
-        if: steps.generate-comment.outcome == 'success'
-        id: find-comment
-        with:
-          issue-number: ${{ steps.pr-number.outputs.pr-number }}
-          comment-author: "github-actions[bot]"
-          body-includes: "<!-- generated-comment typing_conformance_diagnostics_diff -->"
-
-      - name: Create or update comment
-        if: steps.find-comment.outcome == 'success'
-        uses: peter-evans/create-or-update-comment@71345be0265236311c031f5c7866368bd1eff043 # v4
-        with:
-          comment-id: ${{ steps.find-comment.outputs.comment-id }}
-          issue-number: ${{ steps.pr-number.outputs.pr-number }}
-          body-path: comment.txt
-          edit-mode: replace

.pre-commit-config.yaml

@@ -84,7 +84,7 @@ repos:
     rev: v0.12.4
     hooks:
       - id: ruff-format
-      - id: ruff-check
+      - id: ruff
         args: [--fix, --exit-non-zero-on-fix]
         types_or: [python, pyi]
         require_serial: true

CHANGELOG.md

@@ -1,23 +1,5 @@
 # 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

@@ -261,18 +261,6 @@ 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"
@@ -1133,12 +1121,6 @@ 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"
@@ -2566,12 +2548,6 @@ 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"
@@ -2734,7 +2710,7 @@ dependencies = [
 
 [[package]]
 name = "ruff"
-version = "0.12.5"
+version = "0.12.4"
 dependencies = [
  "anyhow",
  "argfile",
@@ -2851,6 +2827,7 @@ dependencies = [
  "anstyle",
  "arc-swap",
  "camino",
+ "countme",
  "dashmap",
  "dunce",
  "etcetera",
@@ -2960,7 +2937,6 @@ version = "0.1.0"
 dependencies = [
  "anyhow",
  "clap",
- "memchr",
  "ruff_cache",
  "ruff_db",
  "ruff_linter",
@@ -2986,7 +2962,7 @@ dependencies = [
 
 [[package]]
 name = "ruff_linter"
-version = "0.12.5"
+version = "0.12.4"
 dependencies = [
  "aho-corasick",
  "anyhow",
@@ -3318,7 +3294,7 @@ dependencies = [
 
 [[package]]
 name = "ruff_wasm"
-version = "0.12.5"
+version = "0.12.4"
 dependencies = [
  "console_error_panic_hook",
  "console_log",
@@ -3792,12 +3768,6 @@ 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"
@@ -4212,7 +4182,6 @@ version = "0.0.0"
 dependencies = [
  "bitflags 2.9.1",
  "insta",
- "itertools 0.14.0",
  "regex",
  "ruff_db",
  "ruff_python_ast",
@@ -4221,10 +4190,11 @@ dependencies = [
  "ruff_source_file",
  "ruff_text_size",
  "rustc-hash",
+ "salsa",
  "smallvec",
  "tracing",
- "ty_project",
  "ty_python_semantic",
+ "ty_vendored",
 ]
 
 [[package]]
@@ -4258,6 +4228,7 @@ dependencies = [
  "thiserror 2.0.12",
  "toml 0.9.2",
  "tracing",
+ "ty_ide",
  "ty_python_semantic",
  "ty_vendored",
 ]
@@ -4268,7 +4239,6 @@ version = "0.0.0"
 dependencies = [
  "anyhow",
  "bitflags 2.9.1",
- "bitvec",
  "camino",
  "colored 3.0.0",
  "compact_str",
@@ -4320,13 +4290,10 @@ dependencies = [
  "anyhow",
  "bitflags 2.9.1",
  "crossbeam",
- "dunce",
- "insta",
  "jod-thread",
  "libc",
  "lsp-server",
  "lsp-types",
- "regex",
  "ruff_db",
  "ruff_notebook",
  "ruff_python_ast",
@@ -4337,7 +4304,6 @@ dependencies = [
  "serde",
  "serde_json",
  "shellexpand",
- "tempfile",
  "thiserror 2.0.12",
  "tracing",
  "tracing-subscriber",
@@ -5126,15 +5092,6 @@ 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

@@ -57,9 +57,6 @@ 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" }

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

crates/ruff/Cargo.toml

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

crates/ruff/src/args.rs

@@ -169,9 +169,6 @@ pub struct AnalyzeGraphCommand {
     /// Attempt to detect imports from string literals.
     #[clap(long)]
     detect_string_imports: bool,
-    /// The minimum number of dots in a string import to consider it a valid import.
-    #[clap(long)]
-    min_dots: Option<usize>,
     /// Enable preview mode. Use `--no-preview` to disable.
     #[arg(long, overrides_with("no_preview"))]
     preview: bool,
@@ -811,7 +808,6 @@ impl AnalyzeGraphCommand {
             } else {
                 None
             },
-            string_imports_min_dots: self.min_dots,
             preview: resolve_bool_arg(self.preview, self.no_preview).map(PreviewMode::from),
             target_version: self.target_version.map(ast::PythonVersion::from),
             ..ExplicitConfigOverrides::default()
@@ -1309,7 +1305,6 @@ struct ExplicitConfigOverrides {
     show_fixes: Option<bool>,
     extension: Option<Vec<ExtensionPair>>,
     detect_string_imports: Option<bool>,
-    string_imports_min_dots: Option<usize>,
 }
 
 impl ConfigurationTransformer for ExplicitConfigOverrides {
@@ -1397,9 +1392,6 @@ impl ConfigurationTransformer for ExplicitConfigOverrides {
         if let Some(detect_string_imports) = &self.detect_string_imports {
             config.analyze.detect_string_imports = Some(*detect_string_imports);
         }
-        if let Some(string_imports_min_dots) = &self.string_imports_min_dots {
-            config.analyze.string_imports_min_dots = Some(*string_imports_min_dots);
-        }
 
         config
     }

crates/ruff/src/cache.rs

@@ -18,14 +18,12 @@ use rustc_hash::FxHashMap;
 use tempfile::NamedTempFile;
 
 use ruff_cache::{CacheKey, CacheKeyHasher};
-use ruff_db::diagnostic::Diagnostic;
+use ruff_db::diagnostic::{Diagnostic, SerializableDiagnostics};
 use ruff_diagnostics::Fix;
-use ruff_linter::message::create_lint_diagnostic;
 use ruff_linter::package::PackageRoot;
 use ruff_linter::{VERSION, warn_user};
 use ruff_macros::CacheKey;
 use ruff_notebook::NotebookIndex;
-use ruff_source_file::SourceFileBuilder;
 use ruff_text_size::{TextRange, TextSize};
 use ruff_workspace::Settings;
 use ruff_workspace::resolver::Resolver;
@@ -345,22 +343,7 @@ impl FileCache {
             let diagnostics = if lint.messages.is_empty() {
                 Vec::new()
             } else {
-                let file = SourceFileBuilder::new(path.to_string_lossy(), &*lint.source).finish();
-                lint.messages
-                    .iter()
-                    .map(|msg| {
-                        create_lint_diagnostic(
-                            &msg.body,
-                            msg.suggestion.as_ref(),
-                            msg.range,
-                            msg.fix.clone(),
-                            msg.parent,
-                            file.clone(),
-                            msg.noqa_offset,
-                            msg.rule,
-                        )
-                    })
-                    .collect()
+                lint.messages.to_diagnostics()
             };
             let notebook_indexes = if let Some(notebook_index) = lint.notebook_index.as_ref() {
                 FxHashMap::from_iter([(path.to_string_lossy().to_string(), notebook_index.clone())])
@@ -415,7 +398,8 @@ pub(crate) struct LintCacheData {
     /// Imports made.
     // pub(super) imports: ImportMap,
     /// Diagnostic messages.
-    pub(super) messages: Vec<CacheMessage>,
+    #[bincode(with_serde)]
+    pub(super) messages: SerializableDiagnostics,
     /// Source code of the file.
     ///
     /// # Notes
@@ -438,30 +422,7 @@ impl LintCacheData {
             String::new() // No messages, no need to keep the source!
         };
 
-        let messages = diagnostics
-            .iter()
-            // Parse the kebab-case rule name into a `Rule`. This will fail for syntax errors, so
-            // this also serves to filter them out, but we shouldn't be caching files with syntax
-            // errors anyway.
-            .filter_map(|msg| Some((msg.name().parse().ok()?, msg)))
-            .map(|(rule, msg)| {
-                // Make sure that all message use the same source file.
-                assert_eq!(
-                    msg.expect_ruff_source_file(),
-                    diagnostics.first().unwrap().expect_ruff_source_file(),
-                    "message uses a different source file"
-                );
-                CacheMessage {
-                    rule,
-                    body: msg.body().to_string(),
-                    suggestion: msg.first_help_text().map(ToString::to_string),
-                    range: msg.expect_range(),
-                    parent: msg.parent(),
-                    fix: msg.fix().cloned(),
-                    noqa_offset: msg.noqa_offset(),
-                }
-            })
-            .collect();
+        let messages = SerializableDiagnostics::new(diagnostics);
 
         Self {
             messages,

crates/ruff/src/commands/analyze_graph.rs

@@ -102,7 +102,7 @@ pub(crate) fn analyze_graph(
 
                 // Resolve the per-file settings.
                 let settings = resolver.resolve(path);
-                let string_imports = settings.analyze.string_imports;
+                let string_imports = settings.analyze.detect_string_imports;
                 let include_dependencies = settings.analyze.include_dependencies.get(path).cloned();
 
                 // Skip excluded files.

crates/ruff/src/commands/check.rs

@@ -279,7 +279,6 @@ mod test {
 
         TextEmitter::default()
             .with_show_fix_status(true)
-            .with_color(false)
             .emit(
                 &mut output,
                 &diagnostics.inner,

crates/ruff/src/printer.rs

@@ -264,7 +264,6 @@ 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/tests/analyze_graph.rs

@@ -197,43 +197,23 @@ fn string_detection() -> Result<()> {
     insta::with_settings!({
         filters => INSTA_FILTERS.to_vec(),
     }, {
-        assert_cmd_snapshot!(command().arg("--detect-string-imports").current_dir(&root), @r#"
-        success: true
-        exit_code: 0
-        ----- stdout -----
-        {
-          "ruff/__init__.py": [],
-          "ruff/a.py": [
-            "ruff/b.py"
-          ],
-          "ruff/b.py": [],
-          "ruff/c.py": []
-        }
+        assert_cmd_snapshot!(command().arg("--detect-string-imports").current_dir(&root), @r###"
+            success: true
+            exit_code: 0
+            ----- stdout -----
+            {
+              "ruff/__init__.py": [],
+              "ruff/a.py": [
+                "ruff/b.py"
+              ],
+              "ruff/b.py": [
+                "ruff/c.py"
+              ],
+              "ruff/c.py": []
+            }
 
-        ----- stderr -----
-        "#);
-    });
-
-    insta::with_settings!({
-        filters => INSTA_FILTERS.to_vec(),
-    }, {
-        assert_cmd_snapshot!(command().arg("--detect-string-imports").arg("--min-dots").arg("1").current_dir(&root), @r#"
-        success: true
-        exit_code: 0
-        ----- stdout -----
-        {
-          "ruff/__init__.py": [],
-          "ruff/a.py": [
-            "ruff/b.py"
-          ],
-          "ruff/b.py": [
-            "ruff/c.py"
-          ],
-          "ruff/c.py": []
-        }
-
-        ----- stderr -----
-        "#);
+            ----- stderr -----
+            "###);
     });
 
     Ok(())

crates/ruff/tests/lint.rs

@@ -2422,7 +2422,7 @@ requires-python = ">= 3.11"
         analyze.exclude = []
         analyze.preview = disabled
         analyze.target_version = 3.11
-        analyze.string_imports = disabled
+        analyze.detect_string_imports = false
         analyze.extension = ExtensionMapping({})
         analyze.include_dependencies = {}
 
@@ -2734,7 +2734,7 @@ requires-python = ">= 3.11"
         analyze.exclude = []
         analyze.preview = disabled
         analyze.target_version = 3.10
-        analyze.string_imports = disabled
+        analyze.detect_string_imports = false
         analyze.extension = ExtensionMapping({})
         analyze.include_dependencies = {}
 
@@ -3098,7 +3098,7 @@ from typing import Union;foo: Union[int, str] = 1
         analyze.exclude = []
         analyze.preview = disabled
         analyze.target_version = 3.11
-        analyze.string_imports = disabled
+        analyze.detect_string_imports = false
         analyze.extension = ExtensionMapping({})
         analyze.include_dependencies = {}
 
@@ -3478,7 +3478,7 @@ from typing import Union;foo: Union[int, str] = 1
         analyze.exclude = []
         analyze.preview = disabled
         analyze.target_version = 3.11
-        analyze.string_imports = disabled
+        analyze.detect_string_imports = false
         analyze.extension = ExtensionMapping({})
         analyze.include_dependencies = {}
 
@@ -3806,7 +3806,7 @@ from typing import Union;foo: Union[int, str] = 1
         analyze.exclude = []
         analyze.preview = disabled
         analyze.target_version = 3.10
-        analyze.string_imports = disabled
+        analyze.detect_string_imports = false
         analyze.extension = ExtensionMapping({})
         analyze.include_dependencies = {}
 
@@ -4134,7 +4134,7 @@ from typing import Union;foo: Union[int, str] = 1
         analyze.exclude = []
         analyze.preview = disabled
         analyze.target_version = 3.9
-        analyze.string_imports = disabled
+        analyze.detect_string_imports = false
         analyze.extension = ExtensionMapping({})
         analyze.include_dependencies = {}
 
@@ -4419,7 +4419,7 @@ from typing import Union;foo: Union[int, str] = 1
         analyze.exclude = []
         analyze.preview = disabled
         analyze.target_version = 3.9
-        analyze.string_imports = disabled
+        analyze.detect_string_imports = false
         analyze.extension = ExtensionMapping({})
         analyze.include_dependencies = {}
 
@@ -4757,7 +4757,7 @@ from typing import Union;foo: Union[int, str] = 1
         analyze.exclude = []
         analyze.preview = disabled
         analyze.target_version = 3.10
-        analyze.string_imports = disabled
+        analyze.detect_string_imports = false
         analyze.extension = ExtensionMapping({})
         analyze.include_dependencies = {}
 

crates/ruff/tests/snapshots/show_settings__display_default_settings.snap

@@ -392,7 +392,7 @@ formatter.docstring_code_line_width = dynamic
 analyze.exclude = []
 analyze.preview = disabled
 analyze.target_version = 3.7
-analyze.string_imports = disabled
+analyze.detect_string_imports = false
 analyze.extension = ExtensionMapping({})
 analyze.include_dependencies = {}
 

crates/ruff_db/Cargo.toml

@@ -25,6 +25,7 @@ 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 }
@@ -58,11 +59,6 @@ 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::{Applicability, Fix};
+use ruff_diagnostics::Fix;
 use ruff_source_file::{LineColumn, SourceCode, SourceFile};
 
 use ruff_annotate_snippets::Level as AnnotateLevel;
@@ -9,6 +9,9 @@ use ruff_text_size::{Ranged, TextRange, TextSize};
 pub use self::render::{DisplayDiagnostic, DisplayDiagnostics, FileResolver, Input};
 use crate::{Db, files::File};
 
+#[cfg(feature = "serde")]
+pub use serde_diagnostics::SerializableDiagnostics;
+
 mod render;
 mod stylesheet;
 
@@ -122,14 +125,7 @@ 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(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));
+        self.sub(SubDiagnostic::new(Severity::Info, message));
     }
 
     /// Adds a "sub" diagnostic to this diagnostic.
@@ -384,15 +380,9 @@ impl Diagnostic {
         self.primary_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 fix suggestion for the violation.
+    pub fn suggestion(&self) -> Option<&str> {
+        self.primary_annotation()?.get_message()
     }
 
     /// Returns the URL for the rule documentation, if it exists.
@@ -578,10 +568,7 @@ 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: SubDiagnosticSeverity,
-        message: impl IntoDiagnosticMessage + 'a,
-    ) -> SubDiagnostic {
+    pub fn new<'a>(severity: Severity, message: impl IntoDiagnosticMessage + 'a) -> SubDiagnostic {
         let inner = Box::new(SubDiagnosticInner {
             severity,
             message: message.into_diagnostic_message(),
@@ -659,7 +646,7 @@ impl SubDiagnostic {
 
 #[derive(Debug, Clone, Eq, PartialEq, get_size2::GetSize)]
 struct SubDiagnosticInner {
-    severity: SubDiagnosticSeverity,
+    severity: Severity,
     message: DiagnosticMessage,
     annotations: Vec<Annotation>,
 }
@@ -806,6 +793,7 @@ impl Annotation {
 /// These tags are used to provide additional information about the annotation.
 /// and are passed through to the language server protocol.
 #[derive(Debug, Clone, Eq, PartialEq, get_size2::GetSize)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub enum DiagnosticTag {
     /// Unused or unnecessary code. Used for unused parameters, unreachable code, etc.
     Unnecessary,
@@ -820,6 +808,7 @@ pub enum DiagnosticTag {
 ///
 /// Rules use kebab case, e.g. `no-foo`.
 #[derive(Debug, Copy, Clone, PartialOrd, Ord, PartialEq, Eq, Hash, get_size2::GetSize)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize))]
 pub struct LintName(&'static str);
 
 impl LintName {
@@ -860,6 +849,7 @@ impl PartialEq<&str> for LintName {
 
 /// Uniquely identifies the kind of a diagnostic.
 #[derive(Debug, Copy, Clone, Eq, PartialEq, PartialOrd, Ord, Hash, get_size2::GetSize)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub enum DiagnosticId {
     Panic,
 
@@ -1157,6 +1147,7 @@ impl From<crate::files::FileRange> for Span {
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Ord, PartialOrd, get_size2::GetSize)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub enum Severity {
     Info,
     Warning,
@@ -1186,32 +1177,6 @@ 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 {
@@ -1238,15 +1203,6 @@ 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 {
@@ -1275,35 +1231,6 @@ 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 {
@@ -1313,9 +1240,6 @@ impl Default for DisplayDiagnosticConfig {
             color: false,
             context: 2,
             preview: false,
-            hide_severity: false,
-            show_fix_status: false,
-            fix_applicability: Applicability::Safe,
         }
     }
 }
@@ -1427,6 +1351,7 @@ impl std::fmt::Display for ConciseMessage<'_> {
 /// a blanket trait implementation for `IntoDiagnosticMessage` for
 /// anything that implements `std::fmt::Display`.
 #[derive(Clone, Debug, Eq, PartialEq, get_size2::GetSize)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub struct DiagnosticMessage(Box<str>);
 
 impl DiagnosticMessage {
@@ -1490,7 +1415,11 @@ impl<T: std::fmt::Display> IntoDiagnosticMessage for T {
 ///
 /// For Ruff rules this means the noqa code.
 #[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Default, Hash, get_size2::GetSize)]
-#[cfg_attr(feature = "serde", derive(serde::Serialize), serde(transparent))]
+#[cfg_attr(
+    feature = "serde",
+    derive(serde::Serialize, serde::Deserialize),
+    serde(transparent)
+)]
 pub struct SecondaryCode(String);
 
 impl SecondaryCode {
@@ -1535,3 +1464,205 @@ impl From<&SecondaryCode> for SecondaryCode {
         value.clone()
     }
 }
+
+#[cfg(feature = "serde")]
+mod serde_diagnostics {
+    use std::sync::Arc;
+
+    use ruff_diagnostics::Fix;
+    use ruff_source_file::{SourceFile, SourceFileBuilder};
+    use ruff_text_size::{TextRange, TextSize};
+    use rustc_hash::FxHashMap;
+    use serde::{Deserialize, Serialize};
+
+    use super::{
+        Annotation, Diagnostic, DiagnosticId, DiagnosticInner, DiagnosticMessage, DiagnosticTag,
+        LintName, SecondaryCode, Severity, Span, SubDiagnostic, SubDiagnosticInner, UnifiedFile,
+    };
+
+    #[derive(Debug, PartialEq, Serialize, Deserialize)]
+    pub struct SerializableDiagnostics {
+        source_files: FxHashMap<String, String>,
+        diagnostics: Vec<SerializableDiagnostic>,
+    }
+
+    impl SerializableDiagnostics {
+        pub fn new(diagnostics: &[Diagnostic]) -> Self {
+            let mut source_files = FxHashMap::default();
+            let mut serializable_diagnostics = Vec::with_capacity(diagnostics.len());
+            for diagnostic in diagnostics {
+                let mut subs = Vec::with_capacity(diagnostic.inner.subs.len());
+                for sub in &diagnostic.inner.subs {
+                    subs.push(SerializableSubDiagnostic {
+                        severity: sub.inner.severity,
+                        message: sub.inner.message.clone(),
+                        annotations: serializable_annotations(
+                            &mut source_files,
+                            &sub.inner.annotations,
+                        ),
+                    });
+                }
+
+                serializable_diagnostics.push(SerializableDiagnostic {
+                    id: diagnostic.inner.id,
+                    severity: diagnostic.inner.severity,
+                    message: diagnostic.inner.message.clone(),
+                    annotations: serializable_annotations(
+                        &mut source_files,
+                        &diagnostic.inner.annotations,
+                    ),
+                    subs,
+                    fix: diagnostic.inner.fix.clone(),
+                    parent: diagnostic.inner.parent,
+                    noqa_offset: diagnostic.inner.noqa_offset,
+                    secondary_code: diagnostic.inner.secondary_code.clone(),
+                });
+            }
+
+            Self {
+                source_files,
+                diagnostics: serializable_diagnostics,
+            }
+        }
+
+        pub fn is_empty(&self) -> bool {
+            self.diagnostics.is_empty()
+        }
+
+        pub fn to_diagnostics(&self) -> Vec<Diagnostic> {
+            let source_files: FxHashMap<&str, SourceFile> = self
+                .source_files
+                .iter()
+                .map(|(name, contents)| {
+                    (
+                        name.as_str(),
+                        SourceFileBuilder::new(name.clone(), contents.clone()).finish(),
+                    )
+                })
+                .collect();
+            self.diagnostics
+                .iter()
+                .map(|diag| Diagnostic {
+                    inner: Arc::new(DiagnosticInner {
+                        id: diag.id,
+                        severity: diag.severity,
+                        message: diag.message.clone(),
+                        annotations: annotations(&source_files, &diag.annotations),
+                        subs: subdiagnostics(&source_files, &diag.subs),
+                        fix: diag.fix.clone(),
+                        parent: diag.parent,
+                        noqa_offset: diag.noqa_offset,
+                        secondary_code: diag.secondary_code.clone(),
+                    }),
+                })
+                .collect()
+        }
+    }
+
+    fn serializable_annotations(
+        source_files: &mut FxHashMap<String, String>,
+        annotations: &[Annotation],
+    ) -> Vec<SerializableAnnotation> {
+        let mut serializable_annotations = Vec::with_capacity(annotations.len());
+        for annotation in annotations {
+            let file = annotation.span.expect_ruff_file();
+            source_files.insert(file.name().to_string(), file.source_text().to_string());
+            serializable_annotations.push(SerializableAnnotation {
+                span: SerializableSpan {
+                    name: file.name().to_string(),
+                    range: annotation.span.range,
+                },
+                message: annotation.message.clone(),
+                is_primary: annotation.is_primary,
+                tags: annotation.tags.clone(),
+            });
+        }
+        serializable_annotations
+    }
+
+    fn annotations(
+        source_files: &FxHashMap<&str, SourceFile>,
+        serializable_annotations: &[SerializableAnnotation],
+    ) -> Vec<Annotation> {
+        serializable_annotations
+            .iter()
+            .map(|ann| {
+                let span = Span {
+                    file: UnifiedFile::Ruff(
+                        source_files
+                            .get(ann.span.name.as_str())
+                            .expect("Expected source file in cache")
+                            .clone(),
+                    ),
+                    range: ann.span.range,
+                };
+                Annotation {
+                    span,
+                    message: ann.message.clone(),
+                    is_primary: ann.is_primary,
+                    tags: ann.tags.clone(),
+                }
+            })
+            .collect()
+    }
+
+    fn subdiagnostics(
+        source_files: &FxHashMap<&str, SourceFile>,
+        serializable_annotations: &[SerializableSubDiagnostic],
+    ) -> Vec<SubDiagnostic> {
+        serializable_annotations
+            .iter()
+            .map(|sub| SubDiagnostic {
+                inner: Box::new(SubDiagnosticInner {
+                    severity: sub.severity,
+                    message: sub.message.clone(),
+                    annotations: annotations(source_files, &sub.annotations),
+                }),
+            })
+            .collect()
+    }
+
+    #[derive(Debug, PartialEq, Serialize, Deserialize)]
+    struct SerializableDiagnostic {
+        id: DiagnosticId,
+        severity: Severity,
+        message: DiagnosticMessage,
+        annotations: Vec<SerializableAnnotation>,
+        subs: Vec<SerializableSubDiagnostic>,
+        fix: Option<Fix>,
+        parent: Option<TextSize>,
+        noqa_offset: Option<TextSize>,
+        secondary_code: Option<SecondaryCode>,
+    }
+
+    #[derive(Debug, PartialEq, Serialize, Deserialize)]
+    struct SerializableAnnotation {
+        span: SerializableSpan,
+        message: Option<DiagnosticMessage>,
+        is_primary: bool,
+        tags: Vec<DiagnosticTag>,
+    }
+
+    #[derive(Debug, PartialEq, Serialize, Deserialize)]
+    struct SerializableSubDiagnostic {
+        severity: Severity,
+        message: DiagnosticMessage,
+        annotations: Vec<SerializableAnnotation>,
+    }
+
+    #[derive(Debug, PartialEq, Serialize, Deserialize)]
+    struct SerializableSpan {
+        name: String,
+        range: Option<TextRange>,
+    }
+
+    impl<'de> Deserialize<'de> for LintName {
+        fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+        where
+            D: serde::Deserializer<'de>,
+        {
+            let s = String::deserialize(deserializer)?.into_boxed_str();
+            Ok(LintName::of(Box::leak(s)))
+        }
+    }
+}

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;
+use crate::diagnostic::stylesheet::{DiagnosticStylesheet, fmt_styled};
 use crate::{
     Db,
     files::File,
@@ -18,17 +18,14 @@ use crate::{
 };
 
 use super::{
-    Annotation, Diagnostic, DiagnosticFormat, DiagnosticSource, DisplayDiagnosticConfig,
+    Annotation, Diagnostic, DiagnosticFormat, DiagnosticSource, DisplayDiagnosticConfig, Severity,
     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")]
@@ -107,7 +104,48 @@ impl std::fmt::Display for DisplayDiagnostics<'_> {
     fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
         match self.config.format {
             DiagnosticFormat::Concise => {
-                ConciseRenderer::new(self.resolver, self.config).render(f, self.diagnostics)?;
+                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())?;
+                }
             }
             DiagnosticFormat::Full => {
                 let stylesheet = if self.config.color {
@@ -218,7 +256,7 @@ impl<'a> Resolved<'a> {
 /// both.)
 #[derive(Debug)]
 struct ResolvedDiagnostic<'a> {
-    level: AnnotateLevel,
+    severity: Severity,
     id: Option<String>,
     message: String,
     annotations: Vec<ResolvedAnnotation<'a>>,
@@ -243,7 +281,7 @@ impl<'a> ResolvedDiagnostic<'a> {
         let id = Some(diag.inner.id.to_string());
         let message = diag.inner.message.as_str().to_string();
         ResolvedDiagnostic {
-            level: diag.inner.severity.to_annotate(),
+            severity: diag.inner.severity,
             id,
             message,
             annotations,
@@ -266,7 +304,7 @@ impl<'a> ResolvedDiagnostic<'a> {
             })
             .collect();
         ResolvedDiagnostic {
-            level: diag.inner.severity.to_annotate(),
+            severity: diag.inner.severity,
             id: None,
             message: diag.inner.message.as_str().to_string(),
             annotations,
@@ -333,7 +371,7 @@ impl<'a> ResolvedDiagnostic<'a> {
         snippets_by_input
             .sort_by(|snips1, snips2| snips1.has_primary.cmp(&snips2.has_primary).reverse());
         RenderableDiagnostic {
-            level: self.level,
+            severity: self.severity,
             id: self.id.as_deref(),
             message: &self.message,
             snippets_by_input,
@@ -421,7 +459,7 @@ struct Renderable<'r> {
 #[derive(Debug)]
 struct RenderableDiagnostic<'r> {
     /// The severity of the diagnostic.
-    level: AnnotateLevel,
+    severity: Severity,
     /// 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.
     ///
@@ -440,6 +478,7 @@ 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
@@ -447,7 +486,7 @@ impl RenderableDiagnostic<'_> {
                 .iter()
                 .map(|snippet| snippet.to_annotate(path))
         });
-        let mut message = self.level.title(self.message);
+        let mut message = level.title(self.message);
         if let Some(id) = self.id {
             message = message.id(id);
         }
@@ -823,12 +862,9 @@ fn relativize_path<'p>(cwd: &SystemPath, path: &'p str) -> &'p str {
 #[cfg(test)]
 mod tests {
 
-    use ruff_diagnostics::{Applicability, Edit, Fix};
+    use ruff_diagnostics::{Edit, Fix};
 
-    use crate::diagnostic::{
-        Annotation, DiagnosticId, IntoDiagnosticMessage, SecondaryCode, Severity, Span,
-        SubDiagnosticSeverity,
-    };
+    use crate::diagnostic::{Annotation, DiagnosticId, SecondaryCode, Severity, Span};
     use crate::files::system_path_to_file;
     use crate::system::{DbWithWritableSystem, SystemPath};
     use crate::tests::TestDb;
@@ -1512,7 +1548,7 @@ watermelon
 
         let mut diag = env.err().primary("animals", "3", "3", "").build();
         diag.sub(
-            env.sub_builder(SubDiagnosticSeverity::Info, "this is a helpful note")
+            env.sub_builder(Severity::Info, "this is a helpful note")
                 .build(),
         );
         insta::assert_snapshot!(
@@ -1541,15 +1577,15 @@ watermelon
 
         let mut diag = env.err().primary("animals", "3", "3", "").build();
         diag.sub(
-            env.sub_builder(SubDiagnosticSeverity::Info, "this is a helpful note")
+            env.sub_builder(Severity::Info, "this is a helpful note")
                 .build(),
         );
         diag.sub(
-            env.sub_builder(SubDiagnosticSeverity::Info, "another helpful note")
+            env.sub_builder(Severity::Info, "another helpful note")
                 .build(),
         );
         diag.sub(
-            env.sub_builder(SubDiagnosticSeverity::Info, "and another helpful note")
+            env.sub_builder(Severity::Info, "and another helpful note")
                 .build(),
         );
         insta::assert_snapshot!(
@@ -2271,27 +2307,6 @@ 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);
@@ -2355,7 +2370,7 @@ watermelon
         /// sub-diagnostic with "error" severity and canned values for
         /// its identifier and message.
         fn sub_warn(&mut self) -> SubDiagnosticBuilder<'_> {
-            self.sub_builder(SubDiagnosticSeverity::Warning, "sub-diagnostic message")
+            self.sub_builder(Severity::Warning, "sub-diagnostic message")
         }
 
         /// Returns a builder for tersely constructing diagnostics.
@@ -2376,11 +2391,7 @@ watermelon
         }
 
         /// Returns a builder for tersely constructing sub-diagnostics.
-        fn sub_builder(
-            &mut self,
-            severity: SubDiagnosticSeverity,
-            message: &str,
-        ) -> SubDiagnosticBuilder<'_> {
+        fn sub_builder(&mut self, severity: Severity, message: &str) -> SubDiagnosticBuilder<'_> {
             let subdiag = SubDiagnostic::new(severity, message);
             SubDiagnosticBuilder { env: self, subdiag }
         }
@@ -2483,12 +2494,6 @@ 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`.
@@ -2595,8 +2600,7 @@ def fibonacci(n):
 
         let diagnostics = vec![
             env.builder("unused-import", Severity::Error, "`os` imported but unused")
-                .primary("fib.py", "1:7", "1:9", "")
-                .help("Remove unused import: `os`")
+                .primary("fib.py", "1:7", "1:9", "Remove unused import: `os`")
                 .secondary_code("F401")
                 .fix(Fix::unsafe_edit(Edit::range_deletion(TextRange::new(
                     TextSize::from(0),
@@ -2609,8 +2613,12 @@ def fibonacci(n):
                 Severity::Error,
                 "Local variable `x` is assigned to but never used",
             )
-            .primary("fib.py", "6:4", "6:5", "")
-            .help("Remove assignment to unused variable `x`")
+            .primary(
+                "fib.py",
+                "6:4",
+                "6:5",
+                "Remove assignment to unused variable `x`",
+            )
             .secondary_code("F841")
             .fix(Fix::unsafe_edit(Edit::deletion(
                 TextSize::from(94),
@@ -2657,25 +2665,6 @@ 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"
@@ -2731,8 +2720,7 @@ if call(foo
 
         let diagnostics = vec![
             env.builder("unused-import", Severity::Error, "`os` imported but unused")
-                .primary("notebook.ipynb", "2:7", "2:9", "")
-                .help("Remove unused import: `os`")
+                .primary("notebook.ipynb", "2:7", "2:9", "Remove unused import: `os`")
                 .secondary_code("F401")
                 .fix(Fix::safe_edit(Edit::range_deletion(TextRange::new(
                     TextSize::from(9),
@@ -2745,8 +2733,12 @@ if call(foo
                 Severity::Error,
                 "`math` imported but unused",
             )
-            .primary("notebook.ipynb", "4:7", "4:11", "")
-            .help("Remove unused import: `math`")
+            .primary(
+                "notebook.ipynb",
+                "4:7",
+                "4:11",
+                "Remove unused import: `math`",
+            )
             .secondary_code("F401")
             .fix(Fix::safe_edit(Edit::range_deletion(TextRange::new(
                 TextSize::from(28),
@@ -2759,8 +2751,12 @@ if call(foo
                 Severity::Error,
                 "Local variable `x` is assigned to but never used",
             )
-            .primary("notebook.ipynb", "10:4", "10:5", "")
-            .help("Remove assignment to unused variable `x`")
+            .primary(
+                "notebook.ipynb",
+                "10:4",
+                "10:5",
+                "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

@@ -1,195 +0,0 @@
-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

@@ -1,66 +0,0 @@
-#[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.first_help_text(),
+        message: diagnostic.suggestion(),
         edits: ExpandedEdits {
             edits: fix.edits(),
             notebook_index,

crates/ruff_db/src/diagnostic/stylesheet.rs

@@ -41,8 +41,6 @@ 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 {
@@ -64,8 +62,6 @@ 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),
         }
     }
 
@@ -79,8 +75,6 @@ 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

@@ -1,6 +1,7 @@
 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;
@@ -311,6 +312,11 @@ 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

@@ -1,6 +1,8 @@
 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;
@@ -36,7 +38,11 @@ pub fn source_text(db: &dyn Db, file: File) -> SourceText {
     };
 
     SourceText {
-        inner: Arc::new(SourceTextInner { kind, read_error }),
+        inner: Arc::new(SourceTextInner {
+            kind,
+            read_error,
+            count: Count::new(),
+        }),
     }
 }
 
@@ -119,6 +125,8 @@ 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/Cargo.toml

@@ -20,7 +20,6 @@ ty_python_semantic = { workspace = true }
 
 anyhow = { workspace = true }
 clap = { workspace = true, optional = true }
-memchr = { workspace = true }
 salsa = { workspace = true }
 schemars = { workspace = true, optional = true }
 serde = { workspace = true, optional = true }

crates/ruff_graph/src/collector.rs

@@ -1,4 +1,3 @@
-use crate::StringImports;
 use ruff_python_ast::visitor::source_order::{
     SourceOrderVisitor, walk_expr, walk_module, walk_stmt,
 };
@@ -11,13 +10,13 @@ pub(crate) struct Collector<'a> {
     /// The path to the current module.
     module_path: Option<&'a [String]>,
     /// Whether to detect imports from string literals.
-    string_imports: StringImports,
+    string_imports: bool,
     /// The collected imports from the Python AST.
     imports: Vec<CollectedImport>,
 }
 
 impl<'a> Collector<'a> {
-    pub(crate) fn new(module_path: Option<&'a [String]>, string_imports: StringImports) -> Self {
+    pub(crate) fn new(module_path: Option<&'a [String]>, string_imports: bool) -> Self {
         Self {
             module_path,
             string_imports,
@@ -119,7 +118,7 @@ impl<'ast> SourceOrderVisitor<'ast> for Collector<'_> {
             | Stmt::Continue(_)
             | Stmt::IpyEscapeCommand(_) => {
                 // Only traverse simple statements when string imports is enabled.
-                if self.string_imports.enabled {
+                if self.string_imports {
                     walk_stmt(self, stmt);
                 }
             }
@@ -127,26 +126,20 @@ impl<'ast> SourceOrderVisitor<'ast> for Collector<'_> {
     }
 
     fn visit_expr(&mut self, expr: &'ast Expr) {
-        if self.string_imports.enabled {
+        if self.string_imports {
             if let Expr::StringLiteral(ast::ExprStringLiteral {
                 value,
                 range: _,
                 node_index: _,
             }) = expr
             {
-                let value = value.to_str();
                 // Determine whether the string literal "looks like" an import statement: contains
-                // the requisite number of dots, and consists solely of valid Python identifiers.
-                if self.string_imports.min_dots == 0
-                    || memchr::memchr_iter(b'.', value.as_bytes()).count()
-                        >= self.string_imports.min_dots
-                {
-                    if let Some(module_name) = ModuleName::new(value) {
-                        self.imports.push(CollectedImport::Import(module_name));
-                    }
+                // a dot, and consists solely of valid Python identifiers.
+                let value = value.to_str();
+                if let Some(module_name) = ModuleName::new(value) {
+                    self.imports.push(CollectedImport::Import(module_name));
                 }
             }
-
             walk_expr(self, expr);
         }
     }

crates/ruff_graph/src/lib.rs

@@ -9,7 +9,7 @@ use ruff_python_parser::{Mode, ParseOptions, parse};
 use crate::collector::Collector;
 pub use crate::db::ModuleDb;
 use crate::resolver::Resolver;
-pub use crate::settings::{AnalyzeSettings, Direction, StringImports};
+pub use crate::settings::{AnalyzeSettings, Direction};
 
 mod collector;
 mod db;
@@ -26,7 +26,7 @@ impl ModuleImports {
         db: &ModuleDb,
         path: &SystemPath,
         package: Option<&SystemPath>,
-        string_imports: StringImports,
+        string_imports: bool,
     ) -> Result<Self> {
         // Read and parse the source code.
         let source = std::fs::read_to_string(path)?;

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(self.db)?.path(self.db))
+                Some(module.file()?.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(self.db)?.path(self.db))
+                Some(module.file()?.path(self.db))
             }
         }
     }

crates/ruff_graph/src/settings.rs

@@ -11,7 +11,7 @@ pub struct AnalyzeSettings {
     pub exclude: FilePatternSet,
     pub preview: PreviewMode,
     pub target_version: PythonVersion,
-    pub string_imports: StringImports,
+    pub detect_string_imports: bool,
     pub include_dependencies: BTreeMap<PathBuf, (PathBuf, Vec<String>)>,
     pub extension: ExtensionMapping,
 }
@@ -26,7 +26,7 @@ impl fmt::Display for AnalyzeSettings {
                 self.exclude,
                 self.preview,
                 self.target_version,
-                self.string_imports,
+                self.detect_string_imports,
                 self.extension | debug,
                 self.include_dependencies | debug,
             ]
@@ -35,31 +35,6 @@ impl fmt::Display for AnalyzeSettings {
     }
 }
 
-#[derive(Debug, Copy, Clone, CacheKey)]
-pub struct StringImports {
-    pub enabled: bool,
-    pub min_dots: usize,
-}
-
-impl Default for StringImports {
-    fn default() -> Self {
-        Self {
-            enabled: false,
-            min_dots: 2,
-        }
-    }
-}
-
-impl fmt::Display for StringImports {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        if self.enabled {
-            write!(f, "enabled (min_dots: {})", self.min_dots)
-        } else {
-            write!(f, "disabled")
-        }
-    }
-}
-
 #[derive(Default, Debug, Copy, Clone, PartialEq, Eq, CacheKey)]
 #[cfg_attr(
     feature = "serde",

crates/ruff_linter/Cargo.toml

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

crates/ruff_linter/resources/test/fixtures/flake8_bandit/S104.py

@@ -25,5 +25,5 @@ def my_func():
 
 # t-strings - all ok
 t"0.0.0.0"
-t"0.0.0.0" t"0.0.0.0{expr}0.0.0.0"
-t"0.0.0.0" t"0.0.0.0{expr}0.0.0.0" t"0.0.0.0{expr}0.0.0.0"
+"0.0.0.0" t"0.0.0.0{expr}0.0.0.0"
+"0.0.0.0" f"0.0.0.0{expr}0.0.0.0" t"0.0.0.0{expr}0.0.0.0"

crates/ruff_linter/resources/test/fixtures/flake8_blind_except/BLE.py

@@ -94,7 +94,7 @@ except Exception:
     logging.error("...", exc_info=True)
 
 
-from logging import critical, error, exception
+from logging import error, exception
 
 try:
     pass
@@ -114,23 +114,6 @@ except Exception:
     error("...", exc_info=None)
 
 
-try:
-    pass
-except Exception:
-    critical("...")
-
-
-try:
-    pass
-except Exception:
-    critical("...", exc_info=False)
-
-
-try:
-    pass
-except Exception:
-    critical("...", exc_info=None)
-
 try:
     pass
 except Exception:
@@ -142,13 +125,6 @@ try:
 except Exception:
     error("...", exc_info=True)
 
-
-try:
-    pass
-except Exception:
-    critical("...", exc_info=True)
-
-
 try:
     ...
 except Exception as e:

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

@@ -142,7 +142,3 @@ 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

@@ -47,19 +47,3 @@ 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

@@ -84,25 +84,3 @@ 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

@@ -278,15 +278,3 @@ 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

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

crates/ruff_linter/resources/test/fixtures/refurb/FURB118.py

@@ -143,23 +143,3 @@ class NotAMethodButHardToDetect:
     # without risking false positives elsewhere or introducing complex heuristics
     # that users would find surprising and confusing
     FOO = sorted([x for x in BAR], key=lambda x: x.baz)
-
-# https://github.com/astral-sh/ruff/issues/19305
-import pytest
-
-@pytest.fixture
-def my_fixture_with_param(request):
-    return request.param
-
-@pytest.fixture()
-def my_fixture_with_param2(request):
-    return request.param
-
-
-# Decorated function (should be ignored)
-def custom_decorator(func):
-    return func
-
-@custom_decorator
-def add(x, y):
-    return x + y

crates/ruff_linter/resources/test/fixtures/ruff/RUF033.py

@@ -65,62 +65,3 @@ class Foo:
     bar = "should've used attrs"
 
     def __post_init__(self, bar: str = "ahhh", baz: str = "hmm") -> None: ...
-
-
-# https://github.com/astral-sh/ruff/issues/18950
-@dataclass
-class Foo:
-    def __post_init__(self, bar: int = (x := 1)) -> None:
-        pass
-
-
-@dataclass
-class Foo:
-    def __post_init__(
-        self,
-        bar: int = (x := 1)  #  comment
-        ,
-        baz: int = (y := 2),  # comment
-        foo = (a := 1)  #  comment
-        ,
-        faz = (b := 2),  # comment
-    ) -> None:
-        pass
-
-
-@dataclass
-class Foo:
-    def __post_init__(
-        self,
-        bar: int = 1,  # comment
-        baz: int = 2,  # comment
-    ) -> None:
-        pass
-
-
-@dataclass
-class Foo:
-    def __post_init__(
-        self,
-        arg1: int = (1)  # comment
-        ,
-        arg2: int = ((1))  # comment
-        ,
-        arg2: int = (i for i in range(10))  # comment
-        ,
-    ) -> None:
-        pass
-
-
-# makes little sense, but is valid syntax
-def fun_with_python_syntax():
-    @dataclass
-    class Foo:
-        def __post_init__(
-            self,
-            bar: (int) = (yield from range(5))  # comment
-            ,
-        ) -> None:
-            ...
-
-    return Foo

crates/ruff_linter/resources/test/fixtures/ruff/RUF039.py

@@ -53,16 +53,3 @@ regex.subn(br"""eak your machine with rm -""", rf"""/""")
 regex.splititer(both, non_literal)
 regex.subf(f, lambda _: r'means', '"format"')
 regex.subfn(fn, f'''a$1n't''', lambda: "'function'")
-
-
-# https://github.com/astral-sh/ruff/issues/16713
-re.compile("\a\f\n\r\t\u27F2\U0001F0A1\v\x41")  # with unsafe fix
-re.compile("\b")  # without fix
-re.compile("\"")  # without fix
-re.compile("\'")  # without fix
-re.compile('\"')  # without fix
-re.compile('\'')  # without fix
-re.compile("\\")  # without fix
-re.compile("\101")  # without fix
-re.compile("a\
-b")  # without fix

crates/ruff_linter/resources/test/fixtures/ruff/RUF039_concat.py

@@ -91,20 +91,3 @@ regex.subf(
     br''br""br''
 )
 regex.subfn(br'I\s\nee*d\s[O0o]me\x20\Qoffe\E, ' br'b')
-
-
-# https://github.com/astral-sh/ruff/issues/16713
-re.compile(
-    "["
-    "\U0001F600-\U0001F64F"  # emoticons
-    "\U0001F300-\U0001F5FF"  # symbols & pictographs
-    "\U0001F680-\U0001F6FF"  # transport & map symbols
-    "\U0001F1E0-\U0001F1FF"  # flags (iOS)
-    "\U00002702-\U000027B0"
-    "\U000024C2-\U0001F251"
-    "\u200d"  # zero width joiner
-    "\u200c"  # zero width non-joiner
-    "\\u200c" # must not be escaped in a raw string
-    "]+",
-    flags=re.UNICODE,
-)

crates/ruff_linter/resources/test/fixtures/ruff/RUF039_py_version_sensitive.py

@@ -1,3 +0,0 @@
-import re
-
-re.compile("\N{Partial Differential}")  # with unsafe fix if python target is 3.8 or higher, else without fix

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

@@ -1039,10 +1039,14 @@ 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,
@@ -1108,18 +1112,6 @@ 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, indexer);
+        pylint::rules::empty_comments(context, comment_ranges, locator);
     }
 
     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::rules::OsChmod),
+        (Flake8UsePathlib, "101") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsChmod),
         (Flake8UsePathlib, "102") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsMkdir),
         (Flake8UsePathlib, "103") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsMakedirs),
-        (Flake8UsePathlib, "104") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsRename),
-        (Flake8UsePathlib, "105") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsReplace),
+        (Flake8UsePathlib, "104") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsRename),
+        (Flake8UsePathlib, "105") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsReplace),
         (Flake8UsePathlib, "106") => (RuleGroup::Stable, rules::flake8_use_pathlib::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::rules::OsPathSamefile),
+        (Flake8UsePathlib, "121") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsPathSamefile),
         (Flake8UsePathlib, "122") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsPathSplitext),
         (Flake8UsePathlib, "123") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::BuiltinOpen),
         (Flake8UsePathlib, "124") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::PyPath),

crates/ruff_linter/src/linter.rs

@@ -473,7 +473,7 @@ pub fn lint_only(
         && !is_py314_support_enabled(settings)
     {
         warn_user_once!(
-            "Support for Python 3.14 is in preview and may undergo breaking changes. Enable `preview` to remove this warning."
+            "Support for Python 3.14 is under development and may be unstable. Enable `preview` to remove this warning."
         );
     }
 
@@ -584,7 +584,7 @@ pub fn lint_fix<'a>(
         && !is_py314_support_enabled(settings)
     {
         warn_user_once!(
-            "Support for Python 3.14 is in preview and may undergo breaking changes. Enable `preview` to remove this warning."
+            "Support for Python 3.14 is under development and may be unstable. Enable `preview` to remove this warning."
         );
     }
 

crates/ruff_linter/src/message/mod.rs

@@ -75,12 +75,11 @@ where
     );
 
     let span = Span::from(file).with_range(range);
-    let annotation = Annotation::primary(span);
-    diagnostic.annotate(annotation);
-
+    let mut annotation = Annotation::primary(span);
     if let Some(suggestion) = suggestion {
-        diagnostic.help(suggestion);
+        annotation = annotation.message(suggestion);
     }
+    diagnostic.annotate(annotation);
 
     if let Some(fix) = fix {
         diagnostic.set_fix(fix);

crates/ruff_linter/src/message/text.rs

@@ -6,12 +6,13 @@ use bitflags::bitflags;
 use colored::Colorize;
 use ruff_annotate_snippets::{Level, Renderer, Snippet};
 
-use ruff_db::diagnostic::{Diagnostic, DiagnosticFormat, DisplayDiagnosticConfig, SecondaryCode};
+use ruff_db::diagnostic::{Diagnostic, SecondaryCode};
 use ruff_notebook::NotebookIndex;
-use ruff_source_file::OneIndexed;
+use ruff_source_file::{LineColumn, 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};
@@ -20,6 +21,8 @@ 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.
@@ -27,27 +30,17 @@ bitflags! {
     }
 }
 
+#[derive(Default)]
 pub struct TextEmitter {
     flags: EmitterFlags,
-    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()),
-        }
-    }
+    unsafe_fixes: UnsafeFixes,
 }
 
 impl TextEmitter {
     #[must_use]
     pub fn with_show_fix_status(mut self, show_fix_status: bool) -> Self {
-        self.config = self.config.show_fix_status(show_fix_status);
+        self.flags
+            .set(EmitterFlags::SHOW_FIX_STATUS, show_fix_status);
         self
     }
 
@@ -65,21 +58,7 @@ impl TextEmitter {
 
     #[must_use]
     pub fn with_unsafe_fixes(mut self, unsafe_fixes: UnsafeFixes) -> Self {
-        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
-    }
-
-    #[must_use]
-    pub fn with_color(mut self, color: bool) -> Self {
-        self.config = self.config.color(color);
+        self.unsafe_fixes = unsafe_fixes;
         self
     }
 }
@@ -92,10 +71,51 @@ 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() {
@@ -166,7 +186,7 @@ pub(super) struct MessageCodeFrame<'a> {
 
 impl Display for MessageCodeFrame<'_> {
     fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
-        let suggestion = self.message.first_help_text();
+        let suggestion = self.message.suggestion();
         let footers = if let Some(suggestion) = suggestion {
             vec![Level::Help.title(suggestion)]
         } else {

crates/ruff_linter/src/preview.rs

@@ -134,26 +134,6 @@ 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_blind_except/rules/blind_except.rs

@@ -47,10 +47,9 @@ use crate::checkers::ast::Checker;
 ///     raise
 /// ```
 ///
-/// Exceptions that are logged via `logging.exception()` or are logged via
-/// `logging.error()` or `logging.critical()` with `exc_info` enabled will
-/// _not_ be flagged, as this is a common pattern for propagating exception
-/// traces:
+/// Exceptions that are logged via `logging.exception()` or `logging.error()`
+/// with `exc_info` enabled will _not_ be flagged, as this is a common pattern
+/// for propagating exception traces:
 /// ```python
 /// try:
 ///     foo()
@@ -202,7 +201,7 @@ impl<'a> StatementVisitor<'a> for LogExceptionVisitor<'a> {
                             ) {
                                 if match attr.as_str() {
                                     "exception" => true,
-                                    "error" | "critical" => arguments
+                                    "error" => arguments
                                         .find_keyword("exc_info")
                                         .is_some_and(|keyword| is_const_true(&keyword.value)),
                                     _ => false,
@@ -215,7 +214,7 @@ impl<'a> StatementVisitor<'a> for LogExceptionVisitor<'a> {
                             if self.semantic.resolve_qualified_name(func).is_some_and(
                                 |qualified_name| match qualified_name.segments() {
                                     ["logging", "exception"] => true,
-                                    ["logging", "error" | "critical"] => arguments
+                                    ["logging", "error"] => arguments
                                         .find_keyword("exc_info")
                                         .is_some_and(|keyword| is_const_true(&keyword.value)),
                                     _ => false,

crates/ruff_linter/src/rules/flake8_blind_except/snapshots/ruff_linter__rules__flake8_blind_except__tests__BLE001_BLE.py.snap

@@ -1,5 +1,6 @@
 ---
 source: crates/ruff_linter/src/rules/flake8_blind_except/mod.rs
+snapshot_kind: text
 ---
 BLE.py:25:8: BLE001 Do not catch blind exception: `BaseException`
    |
@@ -120,30 +121,3 @@ BLE.py:113:8: BLE001 Do not catch blind exception: `Exception`
     |        ^^^^^^^^^ BLE001
 114 |     error("...", exc_info=None)
     |
-
-BLE.py:119:8: BLE001 Do not catch blind exception: `Exception`
-    |
-117 | try:
-118 |     pass
-119 | except Exception:
-    |        ^^^^^^^^^ BLE001
-120 |     critical("...")
-    |
-
-BLE.py:125:8: BLE001 Do not catch blind exception: `Exception`
-    |
-123 | try:
-124 |     pass
-125 | except Exception:
-    |        ^^^^^^^^^ BLE001
-126 |     critical("...", exc_info=False)
-    |
-
-BLE.py:131:8: BLE001 Do not catch blind exception: `Exception`
-    |
-129 | try:
-130 |     pass
-131 | except Exception:
-    |        ^^^^^^^^^ BLE001
-132 |     critical("...", exc_info=None)
-    |

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

@@ -64,7 +64,6 @@ 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(_)) {
@@ -75,7 +74,6 @@ 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
@@ -89,7 +87,7 @@ 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(),
             ));
         }
@@ -106,13 +104,6 @@ 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

@@ -974,8 +974,6 @@ 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`
     |
@@ -983,8 +981,6 @@ 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`
 
@@ -994,15 +990,3 @@ 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

@@ -1162,8 +1162,6 @@ 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`
     |
@@ -1181,8 +1179,6 @@ 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`
     |
@@ -1190,8 +1186,6 @@ 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`
 
@@ -1201,9 +1195,6 @@ 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`
     |
@@ -1211,8 +1202,6 @@ 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`
 
@@ -1222,15 +1211,3 @@ 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, Expr, ExprCall};
-use ruff_python_semantic::{SemanticModel, analyze::typing};
+use ruff_python_ast::{self as ast};
+use ruff_python_ast::{Expr, ExprCall};
 use ruff_text_size::Ranged;
 
 pub(crate) fn is_keyword_only_argument_non_default(arguments: &ast::Arguments, name: &str) -> bool {
@@ -72,85 +72,3 @@ 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

@@ -1,6 +1,5 @@
 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::*;
@@ -15,11 +14,8 @@ 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::*;
@@ -28,7 +24,6 @@ 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;
@@ -43,11 +38,8 @@ 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

@@ -1,94 +0,0 @@
-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

@@ -1,77 +0,0 @@
-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

@@ -1,91 +0,0 @@
-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

@@ -1,94 +0,0 @@
-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

@@ -1,16 +1,14 @@
 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_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,
-    },
+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,
 };
 
 pub(crate) fn replaceable_by_pathlib(checker: &Checker, call: &ExprCall) {
@@ -20,6 +18,24 @@ 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
@@ -35,6 +51,38 @@ 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.
@@ -76,6 +124,8 @@ 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
@@ -184,6 +234,37 @@ 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

@@ -20,7 +20,6 @@ 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()`
    |
@@ -51,7 +50,6 @@ 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()`
    |
@@ -62,7 +60,6 @@ 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()`
    |
@@ -256,7 +253,6 @@ 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

@@ -20,7 +20,6 @@ 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()`
    |
@@ -51,7 +50,6 @@ 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()`
    |
@@ -62,7 +60,6 @@ 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()`
    |
@@ -255,7 +252,6 @@ 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

@@ -20,7 +20,6 @@ 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()`
    |
@@ -51,7 +50,6 @@ 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()`
    |
@@ -62,7 +60,6 @@ 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()`
    |
@@ -256,7 +253,6 @@ 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`
    |
@@ -293,36 +289,3 @@ 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

@@ -20,7 +20,6 @@ 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()`
    |
@@ -51,7 +50,6 @@ 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()`
    |
@@ -62,7 +60,6 @@ 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()`
    |
@@ -255,7 +252,6 @@ 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

@@ -34,7 +34,6 @@ 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()`
    |
@@ -65,7 +64,6 @@ 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()`
    |
@@ -76,7 +74,6 @@ 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()`
    |
@@ -474,7 +471,6 @@ 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

@@ -34,7 +34,6 @@ 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()`
    |
@@ -65,7 +64,6 @@ 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()`
    |
@@ -76,7 +74,6 @@ 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()`
    |
@@ -472,7 +469,6 @@ 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

@@ -35,7 +35,6 @@ 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()`
    |
@@ -66,7 +65,6 @@ 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()`
    |
@@ -77,7 +75,6 @@ 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()`
    |
@@ -487,7 +484,6 @@ 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`
    |
@@ -524,95 +520,3 @@ 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

@@ -35,7 +35,6 @@ 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()`
    |
@@ -66,7 +65,6 @@ 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()`
    |
@@ -77,7 +75,6 @@ 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()`
    |
@@ -485,7 +482,6 @@ 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

@@ -2,6 +2,51 @@ 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`.
 ///
@@ -92,6 +137,99 @@ 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`.
 ///
@@ -209,6 +347,51 @@ 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 and its subclasses
+    // Ignore the do_* methods of the http.server.BaseHTTPRequestHandler class
     if name.starts_with("do_")
         && parent_class.is_some_and(|class| {
             any_base_class(class, semantic, &mut |superclass| {
@@ -108,13 +108,7 @@ pub(crate) fn invalid_function_name(
                 qualified.is_some_and(|name| {
                     matches!(
                         name.segments(),
-                        [
-                            "http",
-                            "server",
-                            "BaseHTTPRequestHandler"
-                                | "CGIHTTPRequestHandler"
-                                | "SimpleHTTPRequestHandler"
-                        ]
+                        ["http", "server", "BaseHTTPRequestHandler"]
                     )
                 })
             })

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

@@ -55,21 +55,3 @@ 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

@@ -406,14 +406,7 @@ fn convert_to_list_extend(
     };
     let target_str = locator.slice(for_stmt.target.range());
     let elt_str = locator.slice(to_append);
-    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 generator_str = 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

@@ -241,27 +241,5 @@ 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

@@ -566,8 +566,6 @@ 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
 
@@ -579,47 +577,3 @@ 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

@@ -48,7 +48,6 @@ 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

@@ -1,5 +1,4 @@
 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};
@@ -50,7 +49,6 @@ pub(crate) fn empty_comments(
     context: &LintContext,
     comment_ranges: &CommentRanges,
     locator: &Locator,
-    indexer: &Indexer,
 ) {
     let block_comments = comment_ranges.block_comments(locator.contents());
 
@@ -61,12 +59,12 @@ pub(crate) fn empty_comments(
         }
 
         // If the line contains an empty comment, add a diagnostic.
-        empty_comment(context, range, locator, indexer);
+        empty_comment(context, range, locator);
     }
 }
 
 /// Return a [`Diagnostic`] if the comment at the given [`TextRange`] is empty.
-fn empty_comment(context: &LintContext, range: TextRange, locator: &Locator, indexer: &Indexer) {
+fn empty_comment(context: &LintContext, range: TextRange, locator: &Locator) {
     // Check: is the comment empty?
     if !locator
         .slice(range)
@@ -97,20 +95,12 @@ fn empty_comment(context: &LintContext, range: TextRange, locator: &Locator, ind
             }
         });
 
-    // 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

@@ -1,36 +0,0 @@
----
-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/refurb/rules/reimplemented_operator.rs

@@ -104,13 +104,6 @@ pub(crate) fn reimplemented_operator(checker: &Checker, target: &FunctionLike) {
         return;
     }
 
-    // Skip decorated functions
-    if let FunctionLike::Function(func) = target {
-        if !func.decorator_list.is_empty() {
-            return;
-        }
-    }
-
     let Some(params) = target.parameters() else {
         return;
     };

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

@@ -555,44 +555,6 @@ mod tests {
         Ok(())
     }
 
-    #[test_case(Rule::UnrawRePattern, Path::new("RUF039_py_version_sensitive.py"))]
-    fn preview_rules_py37(rule_code: Rule, path: &Path) -> Result<()> {
-        let snapshot = format!(
-            "preview__py37__{}_{}",
-            rule_code.noqa_code(),
-            path.to_string_lossy()
-        );
-        let diagnostics = test_path(
-            Path::new("ruff").join(path).as_path(),
-            &settings::LinterSettings {
-                preview: PreviewMode::Enabled,
-                unresolved_target_version: PythonVersion::PY37.into(),
-                ..settings::LinterSettings::for_rule(rule_code)
-            },
-        )?;
-        assert_diagnostics!(snapshot, diagnostics);
-        Ok(())
-    }
-
-    #[test_case(Rule::UnrawRePattern, Path::new("RUF039_py_version_sensitive.py"))]
-    fn preview_rules_py38(rule_code: Rule, path: &Path) -> Result<()> {
-        let snapshot = format!(
-            "preview__py38__{}_{}",
-            rule_code.noqa_code(),
-            path.to_string_lossy()
-        );
-        let diagnostics = test_path(
-            Path::new("ruff").join(path).as_path(),
-            &settings::LinterSettings {
-                preview: PreviewMode::Enabled,
-                unresolved_target_version: PythonVersion::PY38.into(),
-                ..settings::LinterSettings::for_rule(rule_code)
-            },
-        )?;
-        assert_diagnostics!(snapshot, diagnostics);
-        Ok(())
-    }
-
     #[test_case(Rule::UsedDummyVariable, Path::new("RUF052.py"), r"^_+", 1)]
     #[test_case(Rule::UsedDummyVariable, Path::new("RUF052.py"), r"", 2)]
     fn custom_regexp_preset(

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

@@ -2,7 +2,6 @@ use anyhow::Context;
 
 use ruff_macros::{ViolationMetadata, derive_message_formats};
 use ruff_python_ast as ast;
-use ruff_python_ast::parenthesize::parenthesized_range;
 use ruff_python_semantic::{Scope, ScopeKind};
 use ruff_python_trivia::{indentation_at_offset, textwrap};
 use ruff_source_file::LineRanges;
@@ -118,7 +117,13 @@ pub(crate) fn post_init_default(checker: &Checker, function_def: &ast::StmtFunct
 
         if !stopped_fixes {
             diagnostic.try_set_fix(|| {
-                use_initvar(current_scope, function_def, parameter, default, checker)
+                use_initvar(
+                    current_scope,
+                    function_def,
+                    &parameter.parameter,
+                    default,
+                    checker,
+                )
             });
             // Need to stop fixes as soon as there is a parameter we cannot fix.
             // Otherwise, we risk a syntax error (a parameter without a default
@@ -133,11 +138,10 @@ pub(crate) fn post_init_default(checker: &Checker, function_def: &ast::StmtFunct
 fn use_initvar(
     current_scope: &Scope,
     post_init_def: &ast::StmtFunctionDef,
-    parameter_with_default: &ast::ParameterWithDefault,
+    parameter: &ast::Parameter,
     default: &ast::Expr,
     checker: &Checker,
 ) -> anyhow::Result<Fix> {
-    let parameter = &parameter_with_default.parameter;
     if current_scope.has(&parameter.name) {
         return Err(anyhow::anyhow!(
             "Cannot add a `{}: InitVar` field to the class body, as a field by that name already exists",
@@ -153,25 +157,17 @@ fn use_initvar(
         checker.semantic(),
     )?;
 
-    let locator = checker.locator();
-
-    let default_loc = parenthesized_range(
-        default.into(),
-        parameter_with_default.into(),
-        checker.comment_ranges(),
-        checker.source(),
-    )
-    .unwrap_or(default.range());
-
     // Delete the default value. For example,
     // - def __post_init__(self, foo: int = 0) -> None: ...
     // + def __post_init__(self, foo: int) -> None: ...
-    let default_edit = Edit::deletion(parameter.end(), default_loc.end());
+    let default_edit = Edit::deletion(parameter.end(), default.end());
 
     // Add `dataclasses.InitVar` field to class body.
+    let locator = checker.locator();
+
     let content = {
-        let default = locator.slice(default_loc);
         let parameter_name = locator.slice(&parameter.name);
+        let default = locator.slice(default);
         let line_ending = checker.stylist().line_ending().as_str();
 
         if let Some(annotation) = &parameter

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

@@ -1,13 +1,13 @@
 use std::fmt::{Display, Formatter};
 use std::str::FromStr;
 
-use ruff_diagnostics::Applicability;
 use ruff_macros::{ViolationMetadata, derive_message_formats};
 use ruff_python_ast::{
-    BytesLiteral, Expr, ExprBytesLiteral, ExprCall, ExprStringLiteral, PythonVersion, StringLiteral,
+    BytesLiteral, Expr, ExprBytesLiteral, ExprCall, ExprStringLiteral, StringLiteral,
 };
 use ruff_python_semantic::{Modules, SemanticModel};
-use ruff_text_size::{Ranged, TextRange};
+
+use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
 use crate::{Edit, Fix, FixAvailability, Violation};
@@ -24,29 +24,6 @@ use crate::{Edit, Fix, FixAvailability, Violation};
 /// Regular expressions should be written
 /// using raw strings to avoid double escaping.
 ///
-/// ## Fix safety
-/// The fix is unsafe if the string/bytes literal contains an escape sequence because the fix alters
-/// the runtime value of the literal while retaining the regex semantics.
-///
-/// For example
-/// ```python
-/// # Literal is `1\n2`.
-/// re.compile("1\n2")
-///
-/// # Literal is `1\\n2`, but the regex library will interpret `\\n` and will still match a newline
-/// # character as before.
-/// re.compile(r"1\n2")
-/// ```
-///
-/// ## Fix availability
-///  A fix is not available if either
-///  * the argument is a string with a (no-op) `u` prefix (e.g., `u"foo"`) as the prefix is
-///    incompatible with the raw prefix `r`
-///  * the argument is a string or bytes literal with an escape sequence that has a different
-///    meaning in the context of a regular expression such as `\b`, which is word boundary or
-///    backspace in a regex, depending on the context, but always a backspace in string and bytes
-///    literals.
-///
 /// ## Example
 ///
 /// ```python
@@ -186,44 +163,20 @@ fn check_string(checker: &Checker, literal: &StringLiteral, module: RegexModule,
     let range = literal.range;
     let mut diagnostic = checker.report_diagnostic(UnrawRePattern { module, func, kind }, range);
 
-    let Some(applicability) = raw_string_applicability(checker, literal) else {
-        return;
-    };
-
-    diagnostic.set_fix(Fix::applicable_edit(
-        Edit::insertion("r".to_string(), literal.range().start()),
-        applicability,
-    ));
-}
-
-/// Check how safe it is to prepend the `r` prefix to the string.
-///
-/// ## Returns
-///  * `None` if the prefix cannot be added,
-///  * `Some(a)` if it can be added with applicability `a`.
-fn raw_string_applicability(checker: &Checker, literal: &StringLiteral) -> Option<Applicability> {
-    if literal.flags.prefix().is_unicode() {
-        // The (no-op) `u` prefix is a syntax error when combined with `r`
-        return None;
+    if
+    // The (no-op) `u` prefix is a syntax error when combined with `r`
+    !literal.flags.prefix().is_unicode()
+    // We are looking for backslash characters
+    // in the raw source code here, because `\n`
+    // gets converted to a single character already
+    // at the lexing stage.
+    &&!checker.locator().slice(literal.range()).contains('\\')
+    {
+        diagnostic.set_fix(Fix::safe_edit(Edit::insertion(
+            "r".to_string(),
+            literal.range().start(),
+        )));
     }
-
-    if checker.target_version() >= PythonVersion::PY38 {
-        raw_applicability(checker, literal.range(), |escaped| {
-            matches!(
-                escaped,
-                Some('a' | 'f' | 'n' | 'r' | 't' | 'u' | 'U' | 'v' | 'x' | 'N')
-            )
-        })
-    } else {
-        raw_applicability(checker, literal.range(), |escaped| {
-            matches!(
-                escaped,
-                Some('a' | 'f' | 'n' | 'r' | 't' | 'u' | 'U' | 'v' | 'x')
-            )
-        })
-    }
-
-    // re.compile("\a\f\n\N{Partial Differential}\r\t\u27F2\U0001F0A1\v\x41")  # with unsafe fix
 }
 
 fn check_bytes(checker: &Checker, literal: &BytesLiteral, module: RegexModule, func: &str) {
@@ -234,53 +187,5 @@ fn check_bytes(checker: &Checker, literal: &BytesLiteral, module: RegexModule, f
     let kind = PatternKind::Bytes;
     let func = func.to_string();
     let range = literal.range;
-    let mut diagnostic = checker.report_diagnostic(UnrawRePattern { module, func, kind }, range);
-
-    let Some(applicability) = raw_byte_applicability(checker, literal) else {
-        return;
-    };
-
-    diagnostic.set_fix(Fix::applicable_edit(
-        Edit::insertion("r".to_string(), literal.range().start()),
-        applicability,
-    ));
-}
-
-/// Check how same it is to prepend the `r` prefix to the byte sting.
-///
-/// ## Returns
-///  * `None` if the prefix cannot be added,
-///  * `Some(a)` if it can be added with applicability `a`.
-fn raw_byte_applicability(checker: &Checker, literal: &BytesLiteral) -> Option<Applicability> {
-    raw_applicability(checker, literal.range(), |escaped| {
-        matches!(escaped, Some('a' | 'f' | 'n' | 'r' | 't' | 'v' | 'x'))
-    })
-}
-
-fn raw_applicability(
-    checker: &Checker,
-    literal_range: TextRange,
-    match_allowed_escape_sequence: impl Fn(Option<char>) -> bool,
-) -> Option<Applicability> {
-    let mut found_slash = false;
-    let mut chars = checker.locator().slice(literal_range).chars().peekable();
-    while let Some(char) = chars.next() {
-        if char == '\\' {
-            found_slash = true;
-            // Turning `"\uXXXX"` into `r"\uXXXX"` is behaviorally equivalent when passed
-            // to `re`, however, it's not exactly the same runtime value.
-            // Similarly, for the other escape sequences.
-            if !match_allowed_escape_sequence(chars.peek().copied()) {
-                // If the next character is not one of the whitelisted ones, we likely cannot safely turn
-                // this into a raw string.
-                return None;
-            }
-        }
-    }
-
-    Some(if found_slash {
-        Applicability::Unsafe
-    } else {
-        Applicability::Safe
-    })
+    checker.report_diagnostic(UnrawRePattern { module, func, kind }, range);
 }

crates/ruff_linter/src/rules/ruff/snapshots/ruff_linter__rules__ruff__tests__RUF033_RUF033.py.snap

@@ -156,281 +156,3 @@ RUF033.py:67:59: RUF033 `__post_init__` method with argument defaults
    |                                                           ^^^^^ RUF033
    |
    = help: Use `dataclasses.InitVar` instead
-
-RUF033.py:73:41: RUF033 [*] `__post_init__` method with argument defaults
-   |
-71 | @dataclass
-72 | class Foo:
-73 |     def __post_init__(self, bar: int = (x := 1)) -> None:
-   |                                         ^^^^^^ RUF033
-74 |         pass
-   |
-   = help: Use `dataclasses.InitVar` instead
-
-ℹ Unsafe fix
-70 70 | # https://github.com/astral-sh/ruff/issues/18950
-71 71 | @dataclass
-72 72 | class Foo:
-73    |-    def __post_init__(self, bar: int = (x := 1)) -> None:
-   73 |+    bar: InitVar[int] = (x := 1)
-   74 |+    def __post_init__(self, bar: int) -> None:
-74 75 |         pass
-75 76 | 
-76 77 | 
-
-RUF033.py:81:21: RUF033 [*] `__post_init__` method with argument defaults
-   |
-79 |     def __post_init__(
-80 |         self,
-81 |         bar: int = (x := 1)  #  comment
-   |                     ^^^^^^ RUF033
-82 |         ,
-83 |         baz: int = (y := 2),  # comment
-   |
-   = help: Use `dataclasses.InitVar` instead
-
-ℹ Unsafe fix
-76 76 | 
-77 77 | @dataclass
-78 78 | class Foo:
-   79 |+    bar: InitVar[int] = (x := 1)
-79 80 |     def __post_init__(
-80 81 |         self,
-81    |-        bar: int = (x := 1)  #  comment
-   82 |+        bar: int  #  comment
-82 83 |         ,
-83 84 |         baz: int = (y := 2),  # comment
-84 85 |         foo = (a := 1)  #  comment
-
-RUF033.py:83:21: RUF033 [*] `__post_init__` method with argument defaults
-   |
-81 |         bar: int = (x := 1)  #  comment
-82 |         ,
-83 |         baz: int = (y := 2),  # comment
-   |                     ^^^^^^ RUF033
-84 |         foo = (a := 1)  #  comment
-85 |         ,
-   |
-   = help: Use `dataclasses.InitVar` instead
-
-ℹ Unsafe fix
-76 76 | 
-77 77 | @dataclass
-78 78 | class Foo:
-   79 |+    baz: InitVar[int] = (y := 2)
-79 80 |     def __post_init__(
-80 81 |         self,
-81 82 |         bar: int = (x := 1)  #  comment
-82 83 |         ,
-83    |-        baz: int = (y := 2),  # comment
-   84 |+        baz: int,  # comment
-84 85 |         foo = (a := 1)  #  comment
-85 86 |         ,
-86 87 |         faz = (b := 2),  # comment
-
-RUF033.py:84:16: RUF033 [*] `__post_init__` method with argument defaults
-   |
-82 |         ,
-83 |         baz: int = (y := 2),  # comment
-84 |         foo = (a := 1)  #  comment
-   |                ^^^^^^ RUF033
-85 |         ,
-86 |         faz = (b := 2),  # comment
-   |
-   = help: Use `dataclasses.InitVar` instead
-
-ℹ Unsafe fix
-76 76 | 
-77 77 | @dataclass
-78 78 | class Foo:
-   79 |+    foo: InitVar = (a := 1)
-79 80 |     def __post_init__(
-80 81 |         self,
-81 82 |         bar: int = (x := 1)  #  comment
-82 83 |         ,
-83 84 |         baz: int = (y := 2),  # comment
-84    |-        foo = (a := 1)  #  comment
-   85 |+        foo  #  comment
-85 86 |         ,
-86 87 |         faz = (b := 2),  # comment
-87 88 |     ) -> None:
-
-RUF033.py:86:16: RUF033 [*] `__post_init__` method with argument defaults
-   |
-84 |         foo = (a := 1)  #  comment
-85 |         ,
-86 |         faz = (b := 2),  # comment
-   |                ^^^^^^ RUF033
-87 |     ) -> None:
-88 |         pass
-   |
-   = help: Use `dataclasses.InitVar` instead
-
-ℹ Unsafe fix
-76 76 | 
-77 77 | @dataclass
-78 78 | class Foo:
-   79 |+    faz: InitVar = (b := 2)
-79 80 |     def __post_init__(
-80 81 |         self,
-81 82 |         bar: int = (x := 1)  #  comment
---------------------------------------------------------------------------------
-83 84 |         baz: int = (y := 2),  # comment
-84 85 |         foo = (a := 1)  #  comment
-85 86 |         ,
-86    |-        faz = (b := 2),  # comment
-   87 |+        faz,  # comment
-87 88 |     ) -> None:
-88 89 |         pass
-89 90 | 
-
-RUF033.py:95:20: RUF033 [*] `__post_init__` method with argument defaults
-   |
-93 |     def __post_init__(
-94 |         self,
-95 |         bar: int = 1,  # comment
-   |                    ^ RUF033
-96 |         baz: int = 2,  # comment
-97 |     ) -> None:
-   |
-   = help: Use `dataclasses.InitVar` instead
-
-ℹ Unsafe fix
-90 90 | 
-91 91 | @dataclass
-92 92 | class Foo:
-   93 |+    bar: InitVar[int] = 1
-93 94 |     def __post_init__(
-94 95 |         self,
-95    |-        bar: int = 1,  # comment
-   96 |+        bar: int,  # comment
-96 97 |         baz: int = 2,  # comment
-97 98 |     ) -> None:
-98 99 |         pass
-
-RUF033.py:96:20: RUF033 [*] `__post_init__` method with argument defaults
-   |
-94 |         self,
-95 |         bar: int = 1,  # comment
-96 |         baz: int = 2,  # comment
-   |                    ^ RUF033
-97 |     ) -> None:
-98 |         pass
-   |
-   = help: Use `dataclasses.InitVar` instead
-
-ℹ Unsafe fix
-90 90 | 
-91 91 | @dataclass
-92 92 | class Foo:
-   93 |+    baz: InitVar[int] = 2
-93 94 |     def __post_init__(
-94 95 |         self,
-95 96 |         bar: int = 1,  # comment
-96    |-        baz: int = 2,  # comment
-   97 |+        baz: int,  # comment
-97 98 |     ) -> None:
-98 99 |         pass
-99 100 | 
-
-RUF033.py:105:22: RUF033 [*] `__post_init__` method with argument defaults
-    |
-103 |     def __post_init__(
-104 |         self,
-105 |         arg1: int = (1)  # comment
-    |                      ^ RUF033
-106 |         ,
-107 |         arg2: int = ((1))  # comment
-    |
-    = help: Use `dataclasses.InitVar` instead
-
-ℹ Unsafe fix
-100 100 | 
-101 101 | @dataclass
-102 102 | class Foo:
-    103 |+    arg1: InitVar[int] = (1)
-103 104 |     def __post_init__(
-104 105 |         self,
-105     |-        arg1: int = (1)  # comment
-    106 |+        arg1: int  # comment
-106 107 |         ,
-107 108 |         arg2: int = ((1))  # comment
-108 109 |         ,
-
-RUF033.py:107:23: RUF033 [*] `__post_init__` method with argument defaults
-    |
-105 |         arg1: int = (1)  # comment
-106 |         ,
-107 |         arg2: int = ((1))  # comment
-    |                       ^ RUF033
-108 |         ,
-109 |         arg2: int = (i for i in range(10))  # comment
-    |
-    = help: Use `dataclasses.InitVar` instead
-
-ℹ Unsafe fix
-100 100 | 
-101 101 | @dataclass
-102 102 | class Foo:
-    103 |+    arg2: InitVar[int] = ((1))
-103 104 |     def __post_init__(
-104 105 |         self,
-105 106 |         arg1: int = (1)  # comment
-106 107 |         ,
-107     |-        arg2: int = ((1))  # comment
-    108 |+        arg2: int  # comment
-108 109 |         ,
-109 110 |         arg2: int = (i for i in range(10))  # comment
-110 111 |         ,
-
-RUF033.py:109:21: RUF033 [*] `__post_init__` method with argument defaults
-    |
-107 |         arg2: int = ((1))  # comment
-108 |         ,
-109 |         arg2: int = (i for i in range(10))  # comment
-    |                     ^^^^^^^^^^^^^^^^^^^^^^ RUF033
-110 |         ,
-111 |     ) -> None:
-    |
-    = help: Use `dataclasses.InitVar` instead
-
-ℹ Unsafe fix
-100 100 | 
-101 101 | @dataclass
-102 102 | class Foo:
-    103 |+    arg2: InitVar[int] = (i for i in range(10))
-103 104 |     def __post_init__(
-104 105 |         self,
-105 106 |         arg1: int = (1)  # comment
-106 107 |         ,
-107 108 |         arg2: int = ((1))  # comment
-108 109 |         ,
-109     |-        arg2: int = (i for i in range(10))  # comment
-    110 |+        arg2: int  # comment
-110 111 |         ,
-111 112 |     ) -> None:
-112 113 |         pass
-
-RUF033.py:121:27: RUF033 [*] `__post_init__` method with argument defaults
-    |
-119 |         def __post_init__(
-120 |             self,
-121 |             bar: (int) = (yield from range(5))  # comment
-    |                           ^^^^^^^^^^^^^^^^^^^ RUF033
-122 |             ,
-123 |         ) -> None:
-    |
-    = help: Use `dataclasses.InitVar` instead
-
-ℹ Unsafe fix
-116 116 | def fun_with_python_syntax():
-117 117 |     @dataclass
-118 118 |     class Foo:
-    119 |+        bar: InitVar[int] = (yield from range(5))
-119 120 |         def __post_init__(
-120 121 |             self,
-121     |-            bar: (int) = (yield from range(5))  # comment
-    122 |+            bar: (int)  # comment
-122 123 |             ,
-123 124 |         ) -> None:
-124 125 |             ...

crates/ruff_linter/src/rules/ruff/snapshots/ruff_linter__rules__ruff__tests__preview__RUF039_RUF039.py.snap

@@ -21,7 +21,7 @@ RUF039.py:5:12: RUF039 [*] First argument to `re.compile()` is not raw string
 7 7 | re.finditer("dou\ble")
 8 8 | re.fullmatch('''t\riple single''')
 
-RUF039.py:6:12: RUF039 [*] First argument to `re.findall()` is not raw string
+RUF039.py:6:12: RUF039 First argument to `re.findall()` is not raw string
   |
 4 | # Errors
 5 | re.compile('single free-spacing', flags=re.X)
@@ -32,16 +32,6 @@ RUF039.py:6:12: RUF039 [*] First argument to `re.findall()` is not raw string
   |
   = help: Replace with raw string
 
-ℹ Unsafe fix
-3 3 | 
-4 4 | # Errors
-5 5 | re.compile('single free-spacing', flags=re.X)
-6   |-re.findall('si\ngle')
-  6 |+re.findall(r'si\ngle')
-7 7 | re.finditer("dou\ble")
-8 8 | re.fullmatch('''t\riple single''')
-9 9 | re.match("""\triple double""")
-
 RUF039.py:7:13: RUF039 First argument to `re.finditer()` is not raw string
   |
 5 | re.compile('single free-spacing', flags=re.X)
@@ -53,7 +43,7 @@ RUF039.py:7:13: RUF039 First argument to `re.finditer()` is not raw string
   |
   = help: Replace with raw string
 
-RUF039.py:8:14: RUF039 [*] First argument to `re.fullmatch()` is not raw string
+RUF039.py:8:14: RUF039 First argument to `re.fullmatch()` is not raw string
    |
  6 | re.findall('si\ngle')
  7 | re.finditer("dou\ble")
@@ -64,17 +54,7 @@ RUF039.py:8:14: RUF039 [*] First argument to `re.fullmatch()` is not raw string
    |
    = help: Replace with raw string
 
-ℹ Unsafe fix
-5 5 | re.compile('single free-spacing', flags=re.X)
-6 6 | re.findall('si\ngle')
-7 7 | re.finditer("dou\ble")
-8   |-re.fullmatch('''t\riple single''')
-  8 |+re.fullmatch(r'''t\riple single''')
-9 9 | re.match("""\triple double""")
-10 10 | re.search('two', 'args')
-11 11 | re.split("raw", r'second')
-
-RUF039.py:9:10: RUF039 [*] First argument to `re.match()` is not raw string
+RUF039.py:9:10: RUF039 First argument to `re.match()` is not raw string
    |
  7 | re.finditer("dou\ble")
  8 | re.fullmatch('''t\riple single''')
@@ -85,16 +65,6 @@ RUF039.py:9:10: RUF039 [*] First argument to `re.match()` is not raw string
    |
    = help: Replace with raw string
 
-ℹ Unsafe fix
-6  6  | re.findall('si\ngle')
-7  7  | re.finditer("dou\ble")
-8  8  | re.fullmatch('''t\riple single''')
-9     |-re.match("""\triple double""")
-   9  |+re.match(r"""\triple double""")
-10 10 | re.search('two', 'args')
-11 11 | re.split("raw", r'second')
-12 12 | re.sub(u'''nicode''', u"f(?i)rst")
-
 RUF039.py:10:11: RUF039 [*] First argument to `re.search()` is not raw string
    |
  8 | re.fullmatch('''t\riple single''')
@@ -147,7 +117,7 @@ RUF039.py:12:8: RUF039 First argument to `re.sub()` is not raw string
    |
    = help: Replace with raw string
 
-RUF039.py:13:9: RUF039 [*] First argument to `re.subn()` is not raw bytes literal
+RUF039.py:13:9: RUF039 First argument to `re.subn()` is not raw bytes literal
    |
 11 | re.split("raw", r'second')
 12 | re.sub(u'''nicode''', u"f(?i)rst")
@@ -158,16 +128,6 @@ RUF039.py:13:9: RUF039 [*] First argument to `re.subn()` is not raw bytes litera
    |
    = help: Replace with raw bytes literal
 
-ℹ Safe fix
-10 10 | re.search('two', 'args')
-11 11 | re.split("raw", r'second')
-12 12 | re.sub(u'''nicode''', u"f(?i)rst")
-13    |-re.subn(b"""ytes are""", f"\u006e")
-   13 |+re.subn(rb"""ytes are""", f"\u006e")
-14 14 | 
-15 15 | regex.compile('single free-spacing', flags=regex.X)
-16 16 | regex.findall('si\ngle')
-
 RUF039.py:15:15: RUF039 [*] First argument to `regex.compile()` is not raw string
    |
 13 | re.subn(b"""ytes are""", f"\u006e")
@@ -189,7 +149,7 @@ RUF039.py:15:15: RUF039 [*] First argument to `regex.compile()` is not raw strin
 17 17 | regex.finditer("dou\ble")
 18 18 | regex.fullmatch('''t\riple single''')
 
-RUF039.py:16:15: RUF039 [*] First argument to `regex.findall()` is not raw string
+RUF039.py:16:15: RUF039 First argument to `regex.findall()` is not raw string
    |
 15 | regex.compile('single free-spacing', flags=regex.X)
 16 | regex.findall('si\ngle')
@@ -199,16 +159,6 @@ RUF039.py:16:15: RUF039 [*] First argument to `regex.findall()` is not raw strin
    |
    = help: Replace with raw string
 
-ℹ Unsafe fix
-13 13 | re.subn(b"""ytes are""", f"\u006e")
-14 14 | 
-15 15 | regex.compile('single free-spacing', flags=regex.X)
-16    |-regex.findall('si\ngle')
-   16 |+regex.findall(r'si\ngle')
-17 17 | regex.finditer("dou\ble")
-18 18 | regex.fullmatch('''t\riple single''')
-19 19 | regex.match("""\triple double""")
-
 RUF039.py:17:16: RUF039 First argument to `regex.finditer()` is not raw string
    |
 15 | regex.compile('single free-spacing', flags=regex.X)
@@ -220,7 +170,7 @@ RUF039.py:17:16: RUF039 First argument to `regex.finditer()` is not raw string
    |
    = help: Replace with raw string
 
-RUF039.py:18:17: RUF039 [*] First argument to `regex.fullmatch()` is not raw string
+RUF039.py:18:17: RUF039 First argument to `regex.fullmatch()` is not raw string
    |
 16 | regex.findall('si\ngle')
 17 | regex.finditer("dou\ble")
@@ -231,17 +181,7 @@ RUF039.py:18:17: RUF039 [*] First argument to `regex.fullmatch()` is not raw str
    |
    = help: Replace with raw string
 
-ℹ Unsafe fix
-15 15 | regex.compile('single free-spacing', flags=regex.X)
-16 16 | regex.findall('si\ngle')
-17 17 | regex.finditer("dou\ble")
-18    |-regex.fullmatch('''t\riple single''')
-   18 |+regex.fullmatch(r'''t\riple single''')
-19 19 | regex.match("""\triple double""")
-20 20 | regex.search('two', 'args')
-21 21 | regex.split("raw", r'second')
-
-RUF039.py:19:13: RUF039 [*] First argument to `regex.match()` is not raw string
+RUF039.py:19:13: RUF039 First argument to `regex.match()` is not raw string
    |
 17 | regex.finditer("dou\ble")
 18 | regex.fullmatch('''t\riple single''')
@@ -252,16 +192,6 @@ RUF039.py:19:13: RUF039 [*] First argument to `regex.match()` is not raw string
    |
    = help: Replace with raw string
 
-ℹ Unsafe fix
-16 16 | regex.findall('si\ngle')
-17 17 | regex.finditer("dou\ble")
-18 18 | regex.fullmatch('''t\riple single''')
-19    |-regex.match("""\triple double""")
-   19 |+regex.match(r"""\triple double""")
-20 20 | regex.search('two', 'args')
-21 21 | regex.split("raw", r'second')
-22 22 | regex.sub(u'''nicode''', u"f(?i)rst")
-
 RUF039.py:20:14: RUF039 [*] First argument to `regex.search()` is not raw string
    |
 18 | regex.fullmatch('''t\riple single''')
@@ -314,7 +244,7 @@ RUF039.py:22:11: RUF039 First argument to `regex.sub()` is not raw string
    |
    = help: Replace with raw string
 
-RUF039.py:23:12: RUF039 [*] First argument to `regex.subn()` is not raw bytes literal
+RUF039.py:23:12: RUF039 First argument to `regex.subn()` is not raw bytes literal
    |
 21 | regex.split("raw", r'second')
 22 | regex.sub(u'''nicode''', u"f(?i)rst")
@@ -325,16 +255,6 @@ RUF039.py:23:12: RUF039 [*] First argument to `regex.subn()` is not raw bytes li
    |
    = help: Replace with raw bytes literal
 
-ℹ Safe fix
-20 20 | regex.search('two', 'args')
-21 21 | regex.split("raw", r'second')
-22 22 | regex.sub(u'''nicode''', u"f(?i)rst")
-23    |-regex.subn(b"""ytes are""", f"\u006e")
-   23 |+regex.subn(rb"""ytes are""", f"\u006e")
-24 24 | 
-25 25 | regex.template("""(?m)
-26 26 |     (?:ulti)?
-
 RUF039.py:25:16: RUF039 [*] First argument to `regex.template()` is not raw string
    |
 23 |   regex.subn(b"""ytes are""", f"\u006e")
@@ -358,111 +278,3 @@ RUF039.py:25:16: RUF039 [*] First argument to `regex.template()` is not raw stri
 26 26 |     (?:ulti)?
 27 27 |     (?=(?<!(?<=(?!l)))
 28 28 |     l(?i:ne)
-
-RUF039.py:59:12: RUF039 [*] First argument to `re.compile()` is not raw string
-   |
-58 | # https://github.com/astral-sh/ruff/issues/16713
-59 | re.compile("\a\f\n\r\t\u27F2\U0001F0A1\v\x41")  # with unsafe fix
-   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ RUF039
-60 | re.compile("\b")  # without fix
-61 | re.compile("\"")  # without fix
-   |
-   = help: Replace with raw string
-
-ℹ Unsafe fix
-56 56 | 
-57 57 | 
-58 58 | # https://github.com/astral-sh/ruff/issues/16713
-59    |-re.compile("\a\f\n\r\t\u27F2\U0001F0A1\v\x41")  # with unsafe fix
-   59 |+re.compile(r"\a\f\n\r\t\u27F2\U0001F0A1\v\x41")  # with unsafe fix
-60 60 | re.compile("\b")  # without fix
-61 61 | re.compile("\"")  # without fix
-62 62 | re.compile("\'")  # without fix
-
-RUF039.py:60:12: RUF039 First argument to `re.compile()` is not raw string
-   |
-58 | # https://github.com/astral-sh/ruff/issues/16713
-59 | re.compile("\a\f\n\r\t\u27F2\U0001F0A1\v\x41")  # with unsafe fix
-60 | re.compile("\b")  # without fix
-   |            ^^^^ RUF039
-61 | re.compile("\"")  # without fix
-62 | re.compile("\'")  # without fix
-   |
-   = help: Replace with raw string
-
-RUF039.py:61:12: RUF039 First argument to `re.compile()` is not raw string
-   |
-59 | re.compile("\a\f\n\r\t\u27F2\U0001F0A1\v\x41")  # with unsafe fix
-60 | re.compile("\b")  # without fix
-61 | re.compile("\"")  # without fix
-   |            ^^^^ RUF039
-62 | re.compile("\'")  # without fix
-63 | re.compile('\"')  # without fix
-   |
-   = help: Replace with raw string
-
-RUF039.py:62:12: RUF039 First argument to `re.compile()` is not raw string
-   |
-60 | re.compile("\b")  # without fix
-61 | re.compile("\"")  # without fix
-62 | re.compile("\'")  # without fix
-   |            ^^^^ RUF039
-63 | re.compile('\"')  # without fix
-64 | re.compile('\'')  # without fix
-   |
-   = help: Replace with raw string
-
-RUF039.py:63:12: RUF039 First argument to `re.compile()` is not raw string
-   |
-61 | re.compile("\"")  # without fix
-62 | re.compile("\'")  # without fix
-63 | re.compile('\"')  # without fix
-   |            ^^^^ RUF039
-64 | re.compile('\'')  # without fix
-65 | re.compile("\\")  # without fix
-   |
-   = help: Replace with raw string
-
-RUF039.py:64:12: RUF039 First argument to `re.compile()` is not raw string
-   |
-62 | re.compile("\'")  # without fix
-63 | re.compile('\"')  # without fix
-64 | re.compile('\'')  # without fix
-   |            ^^^^ RUF039
-65 | re.compile("\\")  # without fix
-66 | re.compile("\101")  # without fix
-   |
-   = help: Replace with raw string
-
-RUF039.py:65:12: RUF039 First argument to `re.compile()` is not raw string
-   |
-63 | re.compile('\"')  # without fix
-64 | re.compile('\'')  # without fix
-65 | re.compile("\\")  # without fix
-   |            ^^^^ RUF039
-66 | re.compile("\101")  # without fix
-67 | re.compile("a\
-   |
-   = help: Replace with raw string
-
-RUF039.py:66:12: RUF039 First argument to `re.compile()` is not raw string
-   |
-64 | re.compile('\'')  # without fix
-65 | re.compile("\\")  # without fix
-66 | re.compile("\101")  # without fix
-   |            ^^^^^^ RUF039
-67 | re.compile("a\
-68 | b")  # without fix
-   |
-   = help: Replace with raw string
-
-RUF039.py:67:12: RUF039 First argument to `re.compile()` is not raw string
-   |
-65 |   re.compile("\\")  # without fix
-66 |   re.compile("\101")  # without fix
-67 |   re.compile("a\
-   |  ____________^
-68 | | b")  # without fix
-   | |__^ RUF039
-   |
-   = help: Replace with raw string

crates/ruff_linter/src/rules/ruff/snapshots/ruff_linter__rules__ruff__tests__preview__RUF039_RUF039_concat.py.snap

@@ -65,7 +65,7 @@ RUF039_concat.py:12:5: RUF039 [*] First argument to `re.findall()` is not raw st
 14 14 |     """
 15 15 | )
 
-RUF039_concat.py:26:5: RUF039 [*] First argument to `re.match()` is not raw bytes literal
+RUF039_concat.py:26:5: RUF039 First argument to `re.match()` is not raw bytes literal
    |
 24 | )
 25 | re.match(
@@ -76,16 +76,6 @@ RUF039_concat.py:26:5: RUF039 [*] First argument to `re.match()` is not raw byte
    |
    = help: Replace with raw bytes literal
 
-ℹ Safe fix
-23 23 |     f'much?'
-24 24 | )
-25 25 | re.match(
-26    |-    b'reak'
-   26 |+    rb'reak'
-27 27 |     br'eak'
-28 28 | )
-29 29 | re.search(
-
 RUF039_concat.py:30:8: RUF039 First argument to `re.search()` is not raw string
    |
 28 | )
@@ -305,7 +295,7 @@ RUF039_concat.py:52:5: RUF039 [*] First argument to `regex.findall()` is not raw
 54 54 |     """
 55 55 | )
 
-RUF039_concat.py:66:5: RUF039 [*] First argument to `regex.match()` is not raw bytes literal
+RUF039_concat.py:66:5: RUF039 First argument to `regex.match()` is not raw bytes literal
    |
 64 | )
 65 | regex.match(
@@ -316,16 +306,6 @@ RUF039_concat.py:66:5: RUF039 [*] First argument to `regex.match()` is not raw b
    |
    = help: Replace with raw bytes literal
 
-ℹ Safe fix
-63 63 |     f'much?'
-64 64 | )
-65 65 | regex.match(
-66    |-    b'reak'
-   66 |+    rb'reak'
-67 67 |     br'eak'
-68 68 | )
-69 69 | regex.search(
-
 RUF039_concat.py:70:8: RUF039 First argument to `regex.search()` is not raw string
    |
 68 | )
@@ -480,223 +460,3 @@ RUF039_concat.py:78:24: RUF039 [*] First argument to `regex.subn()` is not raw s
 79 79 | 
 80 80 | 
 81 81 | regex.template(
-
-RUF039_concat.py:98:5: RUF039 [*] First argument to `re.compile()` is not raw string
-    |
- 96 | # https://github.com/astral-sh/ruff/issues/16713
- 97 | re.compile(
- 98 |     "["
-    |     ^^^ RUF039
- 99 |     "\U0001F600-\U0001F64F"  # emoticons
-100 |     "\U0001F300-\U0001F5FF"  # symbols & pictographs
-    |
-    = help: Replace with raw string
-
-ℹ Safe fix
-95 95 | 
-96 96 | # https://github.com/astral-sh/ruff/issues/16713
-97 97 | re.compile(
-98    |-    "["
-   98 |+    r"["
-99 99 |     "\U0001F600-\U0001F64F"  # emoticons
-100 100 |     "\U0001F300-\U0001F5FF"  # symbols & pictographs
-101 101 |     "\U0001F680-\U0001F6FF"  # transport & map symbols
-
-RUF039_concat.py:99:5: RUF039 [*] First argument to `re.compile()` is not raw string
-    |
- 97 | re.compile(
- 98 |     "["
- 99 |     "\U0001F600-\U0001F64F"  # emoticons
-    |     ^^^^^^^^^^^^^^^^^^^^^^^ RUF039
-100 |     "\U0001F300-\U0001F5FF"  # symbols & pictographs
-101 |     "\U0001F680-\U0001F6FF"  # transport & map symbols
-    |
-    = help: Replace with raw string
-
-ℹ Unsafe fix
-96  96  | # https://github.com/astral-sh/ruff/issues/16713
-97  97  | re.compile(
-98  98  |     "["
-99      |-    "\U0001F600-\U0001F64F"  # emoticons
-    99  |+    r"\U0001F600-\U0001F64F"  # emoticons
-100 100 |     "\U0001F300-\U0001F5FF"  # symbols & pictographs
-101 101 |     "\U0001F680-\U0001F6FF"  # transport & map symbols
-102 102 |     "\U0001F1E0-\U0001F1FF"  # flags (iOS)
-
-RUF039_concat.py:100:5: RUF039 [*] First argument to `re.compile()` is not raw string
-    |
- 98 |     "["
- 99 |     "\U0001F600-\U0001F64F"  # emoticons
-100 |     "\U0001F300-\U0001F5FF"  # symbols & pictographs
-    |     ^^^^^^^^^^^^^^^^^^^^^^^ RUF039
-101 |     "\U0001F680-\U0001F6FF"  # transport & map symbols
-102 |     "\U0001F1E0-\U0001F1FF"  # flags (iOS)
-    |
-    = help: Replace with raw string
-
-ℹ Unsafe fix
-97  97  | re.compile(
-98  98  |     "["
-99  99  |     "\U0001F600-\U0001F64F"  # emoticons
-100     |-    "\U0001F300-\U0001F5FF"  # symbols & pictographs
-    100 |+    r"\U0001F300-\U0001F5FF"  # symbols & pictographs
-101 101 |     "\U0001F680-\U0001F6FF"  # transport & map symbols
-102 102 |     "\U0001F1E0-\U0001F1FF"  # flags (iOS)
-103 103 |     "\U00002702-\U000027B0"
-
-RUF039_concat.py:101:5: RUF039 [*] First argument to `re.compile()` is not raw string
-    |
- 99 |     "\U0001F600-\U0001F64F"  # emoticons
-100 |     "\U0001F300-\U0001F5FF"  # symbols & pictographs
-101 |     "\U0001F680-\U0001F6FF"  # transport & map symbols
-    |     ^^^^^^^^^^^^^^^^^^^^^^^ RUF039
-102 |     "\U0001F1E0-\U0001F1FF"  # flags (iOS)
-103 |     "\U00002702-\U000027B0"
-    |
-    = help: Replace with raw string
-
-ℹ Unsafe fix
-98  98  |     "["
-99  99  |     "\U0001F600-\U0001F64F"  # emoticons
-100 100 |     "\U0001F300-\U0001F5FF"  # symbols & pictographs
-101     |-    "\U0001F680-\U0001F6FF"  # transport & map symbols
-    101 |+    r"\U0001F680-\U0001F6FF"  # transport & map symbols
-102 102 |     "\U0001F1E0-\U0001F1FF"  # flags (iOS)
-103 103 |     "\U00002702-\U000027B0"
-104 104 |     "\U000024C2-\U0001F251"
-
-RUF039_concat.py:102:5: RUF039 [*] First argument to `re.compile()` is not raw string
-    |
-100 |     "\U0001F300-\U0001F5FF"  # symbols & pictographs
-101 |     "\U0001F680-\U0001F6FF"  # transport & map symbols
-102 |     "\U0001F1E0-\U0001F1FF"  # flags (iOS)
-    |     ^^^^^^^^^^^^^^^^^^^^^^^ RUF039
-103 |     "\U00002702-\U000027B0"
-104 |     "\U000024C2-\U0001F251"
-    |
-    = help: Replace with raw string
-
-ℹ Unsafe fix
-99  99  |     "\U0001F600-\U0001F64F"  # emoticons
-100 100 |     "\U0001F300-\U0001F5FF"  # symbols & pictographs
-101 101 |     "\U0001F680-\U0001F6FF"  # transport & map symbols
-102     |-    "\U0001F1E0-\U0001F1FF"  # flags (iOS)
-    102 |+    r"\U0001F1E0-\U0001F1FF"  # flags (iOS)
-103 103 |     "\U00002702-\U000027B0"
-104 104 |     "\U000024C2-\U0001F251"
-105 105 |     "\u200d"  # zero width joiner
-
-RUF039_concat.py:103:5: RUF039 [*] First argument to `re.compile()` is not raw string
-    |
-101 |     "\U0001F680-\U0001F6FF"  # transport & map symbols
-102 |     "\U0001F1E0-\U0001F1FF"  # flags (iOS)
-103 |     "\U00002702-\U000027B0"
-    |     ^^^^^^^^^^^^^^^^^^^^^^^ RUF039
-104 |     "\U000024C2-\U0001F251"
-105 |     "\u200d"  # zero width joiner
-    |
-    = help: Replace with raw string
-
-ℹ Unsafe fix
-100 100 |     "\U0001F300-\U0001F5FF"  # symbols & pictographs
-101 101 |     "\U0001F680-\U0001F6FF"  # transport & map symbols
-102 102 |     "\U0001F1E0-\U0001F1FF"  # flags (iOS)
-103     |-    "\U00002702-\U000027B0"
-    103 |+    r"\U00002702-\U000027B0"
-104 104 |     "\U000024C2-\U0001F251"
-105 105 |     "\u200d"  # zero width joiner
-106 106 |     "\u200c"  # zero width non-joiner
-
-RUF039_concat.py:104:5: RUF039 [*] First argument to `re.compile()` is not raw string
-    |
-102 |     "\U0001F1E0-\U0001F1FF"  # flags (iOS)
-103 |     "\U00002702-\U000027B0"
-104 |     "\U000024C2-\U0001F251"
-    |     ^^^^^^^^^^^^^^^^^^^^^^^ RUF039
-105 |     "\u200d"  # zero width joiner
-106 |     "\u200c"  # zero width non-joiner
-    |
-    = help: Replace with raw string
-
-ℹ Unsafe fix
-101 101 |     "\U0001F680-\U0001F6FF"  # transport & map symbols
-102 102 |     "\U0001F1E0-\U0001F1FF"  # flags (iOS)
-103 103 |     "\U00002702-\U000027B0"
-104     |-    "\U000024C2-\U0001F251"
-    104 |+    r"\U000024C2-\U0001F251"
-105 105 |     "\u200d"  # zero width joiner
-106 106 |     "\u200c"  # zero width non-joiner
-107 107 |     "\\u200c" # must not be escaped in a raw string
-
-RUF039_concat.py:105:5: RUF039 [*] First argument to `re.compile()` is not raw string
-    |
-103 |     "\U00002702-\U000027B0"
-104 |     "\U000024C2-\U0001F251"
-105 |     "\u200d"  # zero width joiner
-    |     ^^^^^^^^ RUF039
-106 |     "\u200c"  # zero width non-joiner
-107 |     "\\u200c" # must not be escaped in a raw string
-    |
-    = help: Replace with raw string
-
-ℹ Unsafe fix
-102 102 |     "\U0001F1E0-\U0001F1FF"  # flags (iOS)
-103 103 |     "\U00002702-\U000027B0"
-104 104 |     "\U000024C2-\U0001F251"
-105     |-    "\u200d"  # zero width joiner
-    105 |+    r"\u200d"  # zero width joiner
-106 106 |     "\u200c"  # zero width non-joiner
-107 107 |     "\\u200c" # must not be escaped in a raw string
-108 108 |     "]+",
-
-RUF039_concat.py:106:5: RUF039 [*] First argument to `re.compile()` is not raw string
-    |
-104 |     "\U000024C2-\U0001F251"
-105 |     "\u200d"  # zero width joiner
-106 |     "\u200c"  # zero width non-joiner
-    |     ^^^^^^^^ RUF039
-107 |     "\\u200c" # must not be escaped in a raw string
-108 |     "]+",
-    |
-    = help: Replace with raw string
-
-ℹ Unsafe fix
-103 103 |     "\U00002702-\U000027B0"
-104 104 |     "\U000024C2-\U0001F251"
-105 105 |     "\u200d"  # zero width joiner
-106     |-    "\u200c"  # zero width non-joiner
-    106 |+    r"\u200c"  # zero width non-joiner
-107 107 |     "\\u200c" # must not be escaped in a raw string
-108 108 |     "]+",
-109 109 |     flags=re.UNICODE,
-
-RUF039_concat.py:107:5: RUF039 First argument to `re.compile()` is not raw string
-    |
-105 |     "\u200d"  # zero width joiner
-106 |     "\u200c"  # zero width non-joiner
-107 |     "\\u200c" # must not be escaped in a raw string
-    |     ^^^^^^^^^ RUF039
-108 |     "]+",
-109 |     flags=re.UNICODE,
-    |
-    = help: Replace with raw string
-
-RUF039_concat.py:108:5: RUF039 [*] First argument to `re.compile()` is not raw string
-    |
-106 |     "\u200c"  # zero width non-joiner
-107 |     "\\u200c" # must not be escaped in a raw string
-108 |     "]+",
-    |     ^^^^ RUF039
-109 |     flags=re.UNICODE,
-110 | )
-    |
-    = help: Replace with raw string
-
-ℹ Safe fix
-105 105 |     "\u200d"  # zero width joiner
-106 106 |     "\u200c"  # zero width non-joiner
-107 107 |     "\\u200c" # must not be escaped in a raw string
-108     |-    "]+",
-    108 |+    r"]+",
-109 109 |     flags=re.UNICODE,
-110 110 | )

crates/ruff_linter/src/rules/ruff/snapshots/ruff_linter__rules__ruff__tests__preview__py37__RUF039_RUF039_py_version_sensitive.py.snap

@@ -1,11 +0,0 @@
----
-source: crates/ruff_linter/src/rules/ruff/mod.rs
----
-RUF039_py_version_sensitive.py:3:12: RUF039 First argument to `re.compile()` is not raw string
-  |
-1 | import re
-2 |
-3 | re.compile("\N{Partial Differential}")  # with unsafe fix if python target is 3.8 or higher, else without fix
-  |            ^^^^^^^^^^^^^^^^^^^^^^^^^^ RUF039
-  |
-  = help: Replace with raw string

crates/ruff_linter/src/rules/ruff/snapshots/ruff_linter__rules__ruff__tests__preview__py38__RUF039_RUF039_py_version_sensitive.py.snap

@@ -1,17 +0,0 @@
----
-source: crates/ruff_linter/src/rules/ruff/mod.rs
----
-RUF039_py_version_sensitive.py:3:12: RUF039 [*] First argument to `re.compile()` is not raw string
-  |
-1 | import re
-2 |
-3 | re.compile("\N{Partial Differential}")  # with unsafe fix if python target is 3.8 or higher, else without fix
-  |            ^^^^^^^^^^^^^^^^^^^^^^^^^^ RUF039
-  |
-  = help: Replace with raw string
-
-ℹ Unsafe fix
-1 1 | import re
-2 2 | 
-3   |-re.compile("\N{Partial Differential}")  # with unsafe fix if python target is 3.8 or higher, else without fix
-  3 |+re.compile(r"\N{Partial Differential}")  # with unsafe fix if python target is 3.8 or higher, else without fix

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.first_help_text().is_none()),
+                !(fixable && diagnostic.suggestion().is_none()),
                 "Diagnostic emitted by {rule:?} is fixable but \
                 `Violation::fix_title` returns `None`"
             );

crates/ruff_python_ast/src/comparable.rs

@@ -708,10 +708,23 @@ pub struct ComparableTString<'a> {
 }
 
 impl<'a> From<&'a ast::TStringValue> for ComparableTString<'a> {
-    // We model a [`ComparableTString`] on the actual
-    // [CPython implementation] of a `string.templatelib.Template` object.
+    // The approach taken below necessarily deviates from the
+    // corresponding implementation for [`ast::FStringValue`].
+    // The reason is that a t-string value is composed of _three_
+    // non-comparable parts: literals, f-string expressions, and
+    // t-string interpolations. Since we have merged the AST nodes
+    // that capture f-string expressions and t-string interpolations
+    // into the shared [`ast::InterpolatedElement`], we must
+    // be careful to distinguish between them here.
     //
-    // As in CPython, we must be careful to ensure that the length
+    // Consequently, we model a [`ComparableTString`] on the actual
+    // [CPython implementation] of a `string.templatelib.Template` object:
+    // it is composed of `strings` and `interpolations`. In CPython,
+    // the `strings` field is a tuple of honest strings (since f-strings
+    // are evaluated). Our `strings` field will house both f-string
+    // expressions and string literals.
+    //
+    // Finally, as in CPython, we must be careful to ensure that the length
     // of `strings` is always one more than the length of `interpolations` -
     // that way we can recover the original reading order by interleaving
     // starting with `strings`. This is how we can tell the
@@ -755,6 +768,19 @@ impl<'a> From<&'a ast::TStringValue> for ComparableTString<'a> {
                     .push(ComparableInterpolatedStringElement::Literal("".into()));
             }
 
+            fn push_fstring_expression(&mut self, expression: &'a ast::InterpolatedElement) {
+                if let Some(ComparableInterpolatedStringElement::Literal(last_literal)) =
+                    self.strings.last()
+                {
+                    // Recall that we insert empty strings after
+                    // each interpolation. If we encounter an f-string
+                    // expression, we replace the empty string with it.
+                    if last_literal.is_empty() {
+                        self.strings.pop();
+                    }
+                }
+                self.strings.push(expression.into());
+            }
             fn push_tstring_interpolation(&mut self, expression: &'a ast::InterpolatedElement) {
                 self.interpolations.push(expression.into());
                 self.start_new_literal();
@@ -763,13 +789,34 @@ impl<'a> From<&'a ast::TStringValue> for ComparableTString<'a> {
 
         let mut collector = Collector::default();
 
-        for element in value.elements() {
-            match element {
-                ast::InterpolatedStringElement::Literal(literal) => {
-                    collector.push_literal(&literal.value);
+        for part in value {
+            match part {
+                ast::TStringPart::Literal(string_literal) => {
+                    collector.push_literal(&string_literal.value);
                 }
-                ast::InterpolatedStringElement::Interpolation(interpolation) => {
-                    collector.push_tstring_interpolation(interpolation);
+                ast::TStringPart::TString(fstring) => {
+                    for element in &fstring.elements {
+                        match element {
+                            ast::InterpolatedStringElement::Literal(literal) => {
+                                collector.push_literal(&literal.value);
+                            }
+                            ast::InterpolatedStringElement::Interpolation(interpolation) => {
+                                collector.push_tstring_interpolation(interpolation);
+                            }
+                        }
+                    }
+                }
+                ast::TStringPart::FString(fstring) => {
+                    for element in &fstring.elements {
+                        match element {
+                            ast::InterpolatedStringElement::Literal(literal) => {
+                                collector.push_literal(&literal.value);
+                            }
+                            ast::InterpolatedStringElement::Interpolation(expression) => {
+                                collector.push_fstring_expression(expression);
+                            }
+                        }
+                    }
                 }
             }
         }

crates/ruff_python_ast/src/expression.rs

@@ -320,7 +320,7 @@ pub enum StringLikePartIter<'a> {
     String(std::slice::Iter<'a, ast::StringLiteral>),
     Bytes(std::slice::Iter<'a, ast::BytesLiteral>),
     FString(std::slice::Iter<'a, ast::FStringPart>),
-    TString(std::slice::Iter<'a, ast::TString>),
+    TString(std::slice::Iter<'a, ast::TStringPart>),
 }
 
 impl<'a> Iterator for StringLikePartIter<'a> {
@@ -339,7 +339,16 @@ impl<'a> Iterator for StringLikePartIter<'a> {
                     ast::FStringPart::FString(f_string) => StringLikePart::FString(f_string),
                 }
             }
-            StringLikePartIter::TString(inner) => StringLikePart::TString(inner.next()?),
+            StringLikePartIter::TString(inner) => {
+                let part = inner.next()?;
+                match part {
+                    ast::TStringPart::Literal(string_literal) => {
+                        StringLikePart::String(string_literal)
+                    }
+                    ast::TStringPart::TString(t_string) => StringLikePart::TString(t_string),
+                    ast::TStringPart::FString(f_string) => StringLikePart::FString(f_string),
+                }
+            }
         };
 
         Some(part)
@@ -369,7 +378,16 @@ impl DoubleEndedIterator for StringLikePartIter<'_> {
                     ast::FStringPart::FString(f_string) => StringLikePart::FString(f_string),
                 }
             }
-            StringLikePartIter::TString(inner) => StringLikePart::TString(inner.next_back()?),
+            StringLikePartIter::TString(inner) => {
+                let part = inner.next_back()?;
+                match part {
+                    ast::TStringPart::Literal(string_literal) => {
+                        StringLikePart::String(string_literal)
+                    }
+                    ast::TStringPart::TString(t_string) => StringLikePart::TString(t_string),
+                    ast::TStringPart::FString(f_string) => StringLikePart::FString(f_string),
+                }
+            }
         };
 
         Some(part)

crates/ruff_python_ast/src/helpers.rs

@@ -1274,7 +1274,6 @@ impl Truthiness {
                     Self::Unknown
                 }
             }
-            Expr::TString(_) => Self::Truthy,
             Expr::List(ast::ExprList { elts, .. })
             | Expr::Set(ast::ExprSet { elts, .. })
             | Expr::Tuple(ast::ExprTuple { elts, .. }) => {
@@ -1363,7 +1362,6 @@ fn is_non_empty_f_string(expr: &ast::ExprFString) -> bool {
             Expr::EllipsisLiteral(_) => true,
             Expr::List(_) => true,
             Expr::Tuple(_) => true,
-            Expr::TString(_) => true,
 
             // These expressions must resolve to the inner expression.
             Expr::If(ast::ExprIf { body, orelse, .. }) => inner(body) && inner(orelse),
@@ -1388,6 +1386,7 @@ fn is_non_empty_f_string(expr: &ast::ExprFString) -> bool {
             // These literals may or may not be empty.
             Expr::FString(f_string) => is_non_empty_f_string(f_string),
             // These literals may or may not be empty.
+            Expr::TString(f_string) => is_non_empty_t_string(f_string),
             Expr::StringLiteral(ast::ExprStringLiteral { value, .. }) => !value.is_empty(),
             Expr::BytesLiteral(ast::ExprBytesLiteral { value, .. }) => !value.is_empty(),
         }
@@ -1404,6 +1403,76 @@ fn is_non_empty_f_string(expr: &ast::ExprFString) -> bool {
     })
 }
 
+/// Returns `true` if the expression definitely resolves to a non-empty string, when used as an
+/// f-string expression, or `false` if the expression may resolve to an empty string.
+fn is_non_empty_t_string(expr: &ast::ExprTString) -> bool {
+    fn inner(expr: &Expr) -> bool {
+        match expr {
+            // When stringified, these expressions are always non-empty.
+            Expr::Lambda(_) => true,
+            Expr::Dict(_) => true,
+            Expr::Set(_) => true,
+            Expr::ListComp(_) => true,
+            Expr::SetComp(_) => true,
+            Expr::DictComp(_) => true,
+            Expr::Compare(_) => true,
+            Expr::NumberLiteral(_) => true,
+            Expr::BooleanLiteral(_) => true,
+            Expr::NoneLiteral(_) => true,
+            Expr::EllipsisLiteral(_) => true,
+            Expr::List(_) => true,
+            Expr::Tuple(_) => true,
+
+            // These expressions must resolve to the inner expression.
+            Expr::If(ast::ExprIf { body, orelse, .. }) => inner(body) && inner(orelse),
+            Expr::Named(ast::ExprNamed { value, .. }) => inner(value),
+
+            // These expressions are complex. We can't determine whether they're empty or not.
+            Expr::BoolOp(ast::ExprBoolOp { .. }) => false,
+            Expr::BinOp(ast::ExprBinOp { .. }) => false,
+            Expr::UnaryOp(ast::ExprUnaryOp { .. }) => false,
+            Expr::Generator(_) => false,
+            Expr::Await(_) => false,
+            Expr::Yield(_) => false,
+            Expr::YieldFrom(_) => false,
+            Expr::Call(_) => false,
+            Expr::Attribute(_) => false,
+            Expr::Subscript(_) => false,
+            Expr::Starred(_) => false,
+            Expr::Name(_) => false,
+            Expr::Slice(_) => false,
+            Expr::IpyEscapeCommand(_) => false,
+
+            // These literals may or may not be empty.
+            Expr::FString(f_string) => is_non_empty_f_string(f_string),
+            // These literals may or may not be empty.
+            Expr::TString(t_string) => is_non_empty_t_string(t_string),
+            Expr::StringLiteral(ast::ExprStringLiteral { value, .. }) => !value.is_empty(),
+            Expr::BytesLiteral(ast::ExprBytesLiteral { value, .. }) => !value.is_empty(),
+        }
+    }
+
+    expr.value.iter().any(|part| match part {
+        ast::TStringPart::Literal(string_literal) => !string_literal.is_empty(),
+        ast::TStringPart::TString(t_string) => {
+            t_string.elements.iter().all(|element| match element {
+                ast::InterpolatedStringElement::Literal(string_literal) => {
+                    !string_literal.is_empty()
+                }
+                ast::InterpolatedStringElement::Interpolation(t_string) => {
+                    inner(&t_string.expression)
+                }
+            })
+        }
+        ast::TStringPart::FString(f_string) => {
+            f_string.elements.iter().all(|element| match element {
+                InterpolatedStringElement::Literal(string_literal) => !string_literal.is_empty(),
+                InterpolatedStringElement::Interpolation(f_string) => inner(&f_string.expression),
+            })
+        }
+    })
+}
+
 /// Returns `true` if the expression definitely resolves to the empty string, when used as an f-string
 /// expression.
 fn is_empty_f_string(expr: &ast::ExprFString) -> bool {

crates/ruff_python_ast/src/name.rs

@@ -29,10 +29,6 @@ impl Name {
         Self(compact_str::CompactString::const_new(name))
     }
 
-    pub fn shrink_to_fit(&mut self) {
-        self.0.shrink_to_fit();
-    }
-
     pub fn as_str(&self) -> &str {
         self.0.as_str()
     }

crates/ruff_python_ast/src/node.rs

@@ -171,8 +171,18 @@ impl ast::ExprTString {
             node_index: _,
         } = self;
 
-        for t_string in value {
-            visitor.visit_t_string(t_string);
+        for t_string_part in value {
+            match t_string_part {
+                ast::TStringPart::Literal(string_literal) => {
+                    visitor.visit_string_literal(string_literal);
+                }
+                ast::TStringPart::FString(f_string) => {
+                    visitor.visit_f_string(f_string);
+                }
+                ast::TStringPart::TString(t_string) => {
+                    visitor.visit_t_string(t_string);
+                }
+            }
         }
     }
 }

crates/ruff_python_ast/src/nodes.rs

@@ -597,8 +597,8 @@ impl ExprTString {
     /// otherwise.
     pub const fn as_single_part_tstring(&self) -> Option<&TString> {
         match &self.value.inner {
-            TStringValueInner::Single(tstring) => Some(tstring),
-            TStringValueInner::Concatenated(_) => None,
+            TStringValueInner::Single(TStringPart::TString(tstring)) => Some(tstring),
+            _ => None,
         }
     }
 }
@@ -614,7 +614,7 @@ impl TStringValue {
     /// Creates a new t-string literal with a single [`TString`] part.
     pub fn single(value: TString) -> Self {
         Self {
-            inner: TStringValueInner::Single(value),
+            inner: TStringValueInner::Single(TStringPart::TString(value)),
         }
     }
 
@@ -625,7 +625,7 @@ impl TStringValue {
     ///
     /// Panics if `values` has less than 2 elements.
     /// Use [`TStringValue::single`] instead.
-    pub fn concatenated(values: Vec<TString>) -> Self {
+    pub fn concatenated(values: Vec<TStringPart>) -> Self {
         assert!(
             values.len() > 1,
             "Use `TStringValue::single` to create single-part t-strings"
@@ -640,52 +640,78 @@ impl TStringValue {
         matches!(self.inner, TStringValueInner::Concatenated(_))
     }
 
-    /// Returns a slice of all the [`TString`]s contained in this value.
-    pub fn as_slice(&self) -> &[TString] {
+    /// Returns a slice of all the [`TStringPart`]s contained in this value.
+    pub fn as_slice(&self) -> &[TStringPart] {
         match &self.inner {
             TStringValueInner::Single(part) => std::slice::from_ref(part),
             TStringValueInner::Concatenated(parts) => parts,
         }
     }
 
-    /// Returns a mutable slice of all the [`TString`]s contained in this value.
-    fn as_mut_slice(&mut self) -> &mut [TString] {
+    /// Returns a mutable slice of all the [`TStringPart`]s contained in this value.
+    fn as_mut_slice(&mut self) -> &mut [TStringPart] {
         match &mut self.inner {
             TStringValueInner::Single(part) => std::slice::from_mut(part),
             TStringValueInner::Concatenated(parts) => parts,
         }
     }
 
-    /// Returns an iterator over all the [`TString`]s contained in this value.
-    pub fn iter(&self) -> Iter<TString> {
+    /// Returns an iterator over all the [`TStringPart`]s contained in this value.
+    pub fn iter(&self) -> Iter<TStringPart> {
         self.as_slice().iter()
     }
 
-    /// Returns an iterator over all the [`TString`]s contained in this value
+    /// Returns an iterator over all the [`TStringPart`]s contained in this value
     /// that allows modification.
-    pub fn iter_mut(&mut self) -> IterMut<TString> {
+    pub fn iter_mut(&mut self) -> IterMut<TStringPart> {
         self.as_mut_slice().iter_mut()
     }
 
+    /// Returns an iterator over the [`StringLiteral`] parts contained in this value.
+    ///
+    /// Note that this doesn't recurse into the t-string parts. For example,
+    ///
+    /// ```python
+    /// "foo" t"bar {x}" "baz" t"qux"
+    /// ```
+    ///
+    /// Here, the string literal parts returned would be `"foo"` and `"baz"`.
+    pub fn literals(&self) -> impl Iterator<Item = &StringLiteral> {
+        self.iter().filter_map(|part| part.as_literal())
+    }
+
+    /// Returns an iterator over the [`TString`] parts contained in this value.
+    ///
+    /// Note that this doesn't recurse into the t-string parts. For example,
+    ///
+    /// ```python
+    /// "foo" t"bar {x}" "baz" t"qux"
+    /// ```
+    ///
+    /// Here, the t-string parts returned would be `f"bar {x}"` and `f"qux"`.
+    pub fn t_strings(&self) -> impl Iterator<Item = &TString> {
+        self.iter().filter_map(|part| part.as_t_string())
+    }
+
     /// Returns an iterator over all the [`InterpolatedStringElement`] contained in this value.
     ///
-    /// An interpolated string element is what makes up an [`TString`] i.e., it is either a
+    /// An t-string element is what makes up an [`TString`] i.e., it is either a
     /// string literal or an interpolation. In the following example,
     ///
     /// ```python
-    /// t"foo" t"bar {x}" t"baz" t"qux"
+    /// "foo" t"bar {x}" "baz" t"qux"
     /// ```
     ///
-    /// The interpolated string elements returned would be string literal (`"bar "`),
+    /// The t-string elements returned would be string literal (`"bar "`),
     /// interpolation (`x`) and string literal (`"qux"`).
     pub fn elements(&self) -> impl Iterator<Item = &InterpolatedStringElement> {
-        self.iter().flat_map(|tstring| tstring.elements.iter())
+        self.t_strings().flat_map(|fstring| fstring.elements.iter())
     }
 }
 
 impl<'a> IntoIterator for &'a TStringValue {
-    type Item = &'a TString;
-    type IntoIter = Iter<'a, TString>;
+    type Item = &'a TStringPart;
+    type IntoIter = Iter<'a, TStringPart>;
 
     fn into_iter(self) -> Self::IntoIter {
         self.iter()
@@ -693,8 +719,8 @@ impl<'a> IntoIterator for &'a TStringValue {
 }
 
 impl<'a> IntoIterator for &'a mut TStringValue {
-    type Item = &'a mut TString;
-    type IntoIter = IterMut<'a, TString>;
+    type Item = &'a mut TStringPart;
+    type IntoIter = IterMut<'a, TStringPart>;
     fn into_iter(self) -> Self::IntoIter {
         self.iter_mut()
     }
@@ -705,10 +731,43 @@ impl<'a> IntoIterator for &'a mut TStringValue {
 #[cfg_attr(feature = "get-size", derive(get_size2::GetSize))]
 enum TStringValueInner {
     /// A single t-string i.e., `t"foo"`.
-    Single(TString),
+    ///
+    /// This is always going to be `TStringPart::TString` variant which is
+    /// maintained by the `TStringValue::single` constructor.
+    Single(TStringPart),
 
-    /// An implicitly concatenated t-string i.e., `t"foo" t"bar {x}"`.
-    Concatenated(Vec<TString>),
+    /// An implicitly concatenated t-string i.e., `"foo" t"bar {x}"`.
+    Concatenated(Vec<TStringPart>),
+}
+
+/// An t-string part which is either a string literal, an f-string,
+/// or a t-string.
+#[derive(Clone, Debug, PartialEq, is_macro::Is)]
+#[cfg_attr(feature = "get-size", derive(get_size2::GetSize))]
+pub enum TStringPart {
+    Literal(StringLiteral),
+    FString(FString),
+    TString(TString),
+}
+
+impl TStringPart {
+    pub fn quote_style(&self) -> Quote {
+        match self {
+            Self::Literal(string_literal) => string_literal.flags.quote_style(),
+            Self::FString(f_string) => f_string.flags.quote_style(),
+            Self::TString(t_string) => t_string.flags.quote_style(),
+        }
+    }
+}
+
+impl Ranged for TStringPart {
+    fn range(&self) -> TextRange {
+        match self {
+            TStringPart::Literal(string_literal) => string_literal.range(),
+            TStringPart::FString(f_string) => f_string.range(),
+            TStringPart::TString(t_string) => t_string.range(),
+        }
+    }
 }
 
 pub trait StringFlags: Copy {
@@ -1178,12 +1237,6 @@ pub struct TString {
     pub flags: TStringFlags,
 }
 
-impl TString {
-    pub fn quote_style(&self) -> Quote {
-        self.flags.quote_style()
-    }
-}
-
 impl From<TString> for Expr {
     fn from(payload: TString) -> Self {
         ExprTString {

crates/ruff_python_ast/src/visitor.rs

@@ -7,8 +7,8 @@ use crate::{
     self as ast, Alias, AnyParameterRef, Arguments, BoolOp, BytesLiteral, CmpOp, Comprehension,
     Decorator, ElifElseClause, ExceptHandler, Expr, ExprContext, FString, FStringPart,
     InterpolatedStringElement, Keyword, MatchCase, Operator, Parameter, Parameters, Pattern,
-    PatternArguments, PatternKeyword, Stmt, StringLiteral, TString, TypeParam, TypeParamParamSpec,
-    TypeParamTypeVar, TypeParamTypeVarTuple, TypeParams, UnaryOp, WithItem,
+    PatternArguments, PatternKeyword, Stmt, StringLiteral, TString, TStringPart, TypeParam,
+    TypeParamParamSpec, TypeParamTypeVar, TypeParamTypeVarTuple, TypeParams, UnaryOp, WithItem,
 };
 
 /// A trait for AST visitors. Visits all nodes in the AST recursively in evaluation-order.
@@ -547,8 +547,14 @@ pub fn walk_expr<'a, V: Visitor<'a> + ?Sized>(visitor: &mut V, expr: &'a Expr) {
             }
         }
         Expr::TString(ast::ExprTString { value, .. }) => {
-            for t_string in value {
-                visitor.visit_t_string(t_string);
+            for part in value {
+                match part {
+                    TStringPart::Literal(string_literal) => {
+                        visitor.visit_string_literal(string_literal);
+                    }
+                    TStringPart::FString(f_string) => visitor.visit_f_string(f_string),
+                    TStringPart::TString(t_string) => visitor.visit_t_string(t_string),
+                }
             }
         }
         Expr::StringLiteral(ast::ExprStringLiteral { value, .. }) => {

crates/ruff_python_ast/src/visitor/source_order.rs

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

crates/ruff_python_ast/src/visitor/transformer.rs

@@ -533,8 +533,18 @@ pub fn walk_expr<V: Transformer + ?Sized>(visitor: &V, expr: &mut Expr) {
             }
         }
         Expr::TString(ast::ExprTString { value, .. }) => {
-            for t_string in value.iter_mut() {
-                visitor.visit_t_string(t_string);
+            for t_string_part in value.iter_mut() {
+                match t_string_part {
+                    ast::TStringPart::Literal(string_literal) => {
+                        visitor.visit_string_literal(string_literal);
+                    }
+                    ast::TStringPart::FString(f_string) => {
+                        visitor.visit_f_string(f_string);
+                    }
+                    ast::TStringPart::TString(t_string) => {
+                        visitor.visit_t_string(t_string);
+                    }
+                }
             }
         }
         Expr::StringLiteral(ast::ExprStringLiteral { value, .. }) => {