Bump version to 0.0.185

.github/workflows/ci.yaml

@@ -115,7 +115,9 @@ jobs:
             ${{ runner.os }}-build-${{ env.cache-name }}-
             ${{ runner.os }}-build-
             ${{ runner.os }}-
+      - run: pip install black[d]==22.12.0
       - run: cargo test --all
+      - run: cargo test --package ruff --test black_compatibility_test -- --ignored
 
   maturin_build:
     name: "maturin build"

.pre-commit-config.yaml

@@ -1,6 +1,6 @@
 repos:
   - repo: https://github.com/charliermarsh/ruff-pre-commit
-    rev: v0.0.177
+    rev: v0.0.185
     hooks:
       - id: ruff
 

BREAKING_CHANGES.md

@@ -0,0 +1,23 @@
+# Breaking Changes
+
+## 0.0.181
+
+### Files excluded by `.gitignore` are now ignored ([#1234](https://github.com/charliermarsh/ruff/pull/1234))
+
+Ruff will now avoid checking files that are excluded by `.ignore`, `.gitignore`,
+`.git/info/exclude`, and global `gitignore` files. This behavior is powered by the [`ignore`](https://docs.rs/ignore/latest/ignore/struct.WalkBuilder.html#ignore-rules)
+crate, and is applied in addition to Ruff's built-in `exclude` system.
+
+To disable this behavior, set `respect-gitignore = false` in your `pyproject.toml` file.
+
+Note that hidden files (i.e., files and directories prefixed with a `.`) are _not_ ignored by
+default.
+
+## 0.0.178
+
+### Configuration files are now resolved hierarchically ([#1190](https://github.com/charliermarsh/ruff/pull/1190))
+
+`pyproject.toml` files are now resolved hierarchically, such that for each Python file, we find
+the first `pyproject.toml` file in its path, and use that to determine its lint settings.
+
+See the [README](https://github.com/charliermarsh/ruff#pyprojecttoml-discovery) for more.

Cargo.lock

@@ -724,7 +724,7 @@ checksum = "0ce7134b9999ecaf8bcd65542e436736ef32ddca1b3e06094cb6ec5755203b80"
 
 [[package]]
 name = "flake8-to-ruff"
-version = "0.0.177-dev.0"
+version = "0.0.185-dev.0"
 dependencies = [
  "anyhow",
  "clap 4.0.29",
@@ -796,6 +796,12 @@ dependencies = [
  "wasm-bindgen",
 ]
 
+[[package]]
+name = "glob"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9b919933a397b79c37e33b77bb2aa3dc8eb6e165ad809e58ff75bc7db2e34574"
+
 [[package]]
 name = "globset"
 version = "0.4.9"
@@ -888,6 +894,24 @@ dependencies = [
  "unicode-normalization",
 ]
 
+[[package]]
+name = "ignore"
+version = "0.4.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "713f1b139373f96a2e0ce3ac931cd01ee973c3c5dd7c40c0c2efe96ad2b6751d"
+dependencies = [
+ "crossbeam-utils",
+ "globset",
+ "lazy_static",
+ "log",
+ "memchr",
+ "regex",
+ "same-file",
+ "thread_local",
+ "walkdir",
+ "winapi-util",
+]
+
 [[package]]
 name = "indexmap"
 version = "1.9.2"
@@ -1821,7 +1845,7 @@ dependencies = [
 
 [[package]]
 name = "ruff"
-version = "0.0.177"
+version = "0.0.185"
 dependencies = [
  "annotate-snippets 0.9.1",
  "anyhow",
@@ -1841,7 +1865,9 @@ dependencies = [
  "fern",
  "filetime",
  "getrandom 0.2.8",
+ "glob",
  "globset",
+ "ignore",
  "insta",
  "itertools",
  "libcst",
@@ -1869,12 +1895,13 @@ dependencies = [
  "titlecase",
  "toml",
  "update-informer",
+ "ureq",
  "walkdir",
 ]
 
 [[package]]
 name = "ruff_dev"
-version = "0.0.177"
+version = "0.0.185"
 dependencies = [
  "anyhow",
  "clap 4.0.29",
@@ -1892,7 +1919,7 @@ dependencies = [
 
 [[package]]
 name = "ruff_macros"
-version = "0.0.177"
+version = "0.0.185"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -1935,7 +1962,7 @@ dependencies = [
 [[package]]
 name = "rustpython-ast"
 version = "0.1.0"
-source = "git+https://github.com/RustPython/RustPython.git?rev=2edd0d264c50c7807bcff03a52a6509e8b7f187f#2edd0d264c50c7807bcff03a52a6509e8b7f187f"
+source = "git+https://github.com/RustPython/RustPython.git?rev=8d879a53197f9c73062f6160410bdba796a71cbf#8d879a53197f9c73062f6160410bdba796a71cbf"
 dependencies = [
  "num-bigint",
  "rustpython-common",
@@ -1945,7 +1972,7 @@ dependencies = [
 [[package]]
 name = "rustpython-common"
 version = "0.0.0"
-source = "git+https://github.com/RustPython/RustPython.git?rev=2edd0d264c50c7807bcff03a52a6509e8b7f187f#2edd0d264c50c7807bcff03a52a6509e8b7f187f"
+source = "git+https://github.com/RustPython/RustPython.git?rev=8d879a53197f9c73062f6160410bdba796a71cbf#8d879a53197f9c73062f6160410bdba796a71cbf"
 dependencies = [
  "ascii",
  "cfg-if 1.0.0",
@@ -1968,7 +1995,7 @@ dependencies = [
 [[package]]
 name = "rustpython-compiler-core"
 version = "0.1.2"
-source = "git+https://github.com/RustPython/RustPython.git?rev=2edd0d264c50c7807bcff03a52a6509e8b7f187f#2edd0d264c50c7807bcff03a52a6509e8b7f187f"
+source = "git+https://github.com/RustPython/RustPython.git?rev=8d879a53197f9c73062f6160410bdba796a71cbf#8d879a53197f9c73062f6160410bdba796a71cbf"
 dependencies = [
  "bincode",
  "bitflags",
@@ -1985,7 +2012,7 @@ dependencies = [
 [[package]]
 name = "rustpython-parser"
 version = "0.1.2"
-source = "git+https://github.com/RustPython/RustPython.git?rev=2edd0d264c50c7807bcff03a52a6509e8b7f187f#2edd0d264c50c7807bcff03a52a6509e8b7f187f"
+source = "git+https://github.com/RustPython/RustPython.git?rev=8d879a53197f9c73062f6160410bdba796a71cbf#8d879a53197f9c73062f6160410bdba796a71cbf"
 dependencies = [
  "ahash",
  "anyhow",
@@ -2297,6 +2324,15 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "thread_local"
+version = "1.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5516c27b78311c50bf42c071425c560ac799b11c30b31f87e3081965fe5e0180"
+dependencies = [
+ "once_cell",
+]
+
 [[package]]
 name = "time"
 version = "0.1.45"

Cargo.toml

@@ -6,7 +6,7 @@ members = [
 
 [package]
 name = "ruff"
-version = "0.0.177"
+version = "0.0.185"
 edition = "2021"
 rust-version = "1.65.0"
 
@@ -28,7 +28,9 @@ common-path = { version = "1.0.0" }
 dirs = { version = "4.0.0" }
 fern = { version = "0.6.1" }
 filetime = { version = "0.2.17" }
+glob = { version = "0.3.0" }
 globset = { version = "0.4.9" }
+ignore = { version = "0.4.18" }
 itertools = { version = "0.10.5" }
 libcst = { git = "https://github.com/charliermarsh/LibCST", rev = "f2f0b7a487a8725d161fe8b3ed73a6758b21e177" }
 log = { version = "0.4.17" }
@@ -41,11 +43,11 @@ quick-junit = { version = "0.3.2" }
 rayon = { version = "1.5.3" }
 regex = { version = "1.6.0" }
 ropey = { version = "1.5.0", features = ["cr_lines", "simd"], default-features = false }
-ruff_macros = { version = "0.0.177", path = "ruff_macros" }
+ruff_macros = { version = "0.0.185", path = "ruff_macros" }
 rustc-hash = { version = "1.1.0" }
-rustpython-ast = { features = ["unparse"], git = "https://github.com/RustPython/RustPython.git", rev = "2edd0d264c50c7807bcff03a52a6509e8b7f187f" }
-rustpython-common = { git = "https://github.com/RustPython/RustPython.git", rev = "2edd0d264c50c7807bcff03a52a6509e8b7f187f" }
-rustpython-parser = { features = ["lalrpop"], git = "https://github.com/RustPython/RustPython.git", rev = "2edd0d264c50c7807bcff03a52a6509e8b7f187f" }
+rustpython-ast = { features = ["unparse"], git = "https://github.com/RustPython/RustPython.git", rev = "8d879a53197f9c73062f6160410bdba796a71cbf" }
+rustpython-common = { git = "https://github.com/RustPython/RustPython.git", rev = "8d879a53197f9c73062f6160410bdba796a71cbf" }
+rustpython-parser = { features = ["lalrpop"], git = "https://github.com/RustPython/RustPython.git", rev = "8d879a53197f9c73062f6160410bdba796a71cbf" }
 serde = { version = "1.0.147", features = ["derive"] }
 serde_json = { version = "1.0.87" }
 strum = { version = "0.24.1", features = ["strum_macros"] }
@@ -69,6 +71,7 @@ assert_cmd = { version = "2.0.4" }
 criterion = { version = "0.4.0" }
 insta = { version = "1.19.1", features = ["yaml"] }
 test-case = { version = "2.2.2" }
+ureq = { version = "2.5.0", features = [] }
 
 [features]
 default = ["update-informer"]

README.md

@@ -86,6 +86,7 @@ of [Conda](https://docs.conda.io/en/latest/):
    1. [flake8-builtins (A)](#flake8-builtins-a)
    1. [flake8-comprehensions (C4)](#flake8-comprehensions-c4)
    1. [flake8-debugger (T10)](#flake8-debugger-t10)
+   1. [flake8-errmsg (EM)](#flake8-errmsg-em)
    1. [flake8-import-conventions (ICN)](#flake8-import-conventions-icn)
    1. [flake8-print (T20)](#flake8-print-t20)
    1. [flake8-quotes (Q)](#flake8-quotes-q)
@@ -94,6 +95,7 @@ of [Conda](https://docs.conda.io/en/latest/):
    1. [flake8-tidy-imports (TID)](#flake8-tidy-imports-tid)
    1. [flake8-unused-arguments (ARG)](#flake8-unused-arguments-arg)
    1. [eradicate (ERA)](#eradicate-era)
+   1. [pandas-vet (PDV)](#pandas-vet-pdv)
    1. [pygrep-hooks (PGH)](#pygrep-hooks-pgh)
    1. [Pylint (PLC, PLE, PLR, PLW)](#pylint-plc-ple-plr-plw)
    1. [Ruff-specific rules (RUF)](#ruff-specific-rules-ruf)<!-- End auto-generated table of contents. -->
@@ -155,7 +157,7 @@ Ruff also works with [pre-commit](https://pre-commit.com):
 ```yaml
 repos:
   - repo: https://github.com/charliermarsh/ruff-pre-commit
-    rev: v0.0.177
+    rev: v0.0.185
     hooks:
       - id: ruff
 ```
@@ -304,13 +306,15 @@ Options:
       --per-file-ignores <PER_FILE_IGNORES>
           List of mappings from file pattern to code to exclude
       --format <FORMAT>
-          Output serialization format for error messages [default: text] [possible values: text, json, junit, grouped]
+          Output serialization format for error messages [possible values: text, json, junit, grouped, github]
       --show-source
           Show violations with source code
+      --respect-gitignore
+          Respect file exclusions via `.gitignore` and other standard ignore files
       --show-files
           See the files Ruff will be run against with the current settings
       --show-settings
-          See Ruff's settings
+          See the settings Ruff will use to check a given Python file
       --add-noqa
           Enable automatic additions of noqa directives to failing lines
       --dummy-variable-rgx <DUMMY_VARIABLE_RGX>
@@ -331,6 +335,55 @@ Options:
           Print version information
 ```
 
+### `pyproject.toml` discovery
+
+Similar to [ESLint](https://eslint.org/docs/latest/user-guide/configuring/configuration-files#cascading-and-hierarchy),
+Ruff supports hierarchical configuration, such that the "closest" `pyproject.toml` file in the
+directory hierarchy is used for every individual file, with all paths in the `pyproject.toml` file
+(e.g., `exclude` globs, `src` paths) being resolved relative to the directory containing the
+`pyproject.toml` file.
+
+There are a few exceptions to these rules:
+
+1. In locating the "closest" `pyproject.toml` file for a given path, Ruff ignore any
+   `pyproject.toml` files that lack a `[tool.ruff]` section.
+2. If a configuration file is passed directly via `--config`, those settings are used for across
+   files. Any relative paths in that configuration file (like `exclude` globs or `src` paths) are
+   resolved relative to the _current working directory_.
+3. If no `pyproject.toml` file is found in the filesystem hierarchy, Ruff will fall back to using
+   a default configuration. If a user-specific configuration file exists
+   at `${config_dir}/ruff/pyproject.toml`,
+   that file will be used instead of the default configuration, with `${config_dir}` being
+   determined via the [`dirs](https://docs.rs/dirs/4.0.0/dirs/fn.config_dir.html) crate, and all
+   relative paths being again resolved relative to the _current working directory_.
+4. Any `pyproject.toml`-supported settings that are provided on the command-line (e.g., via
+   `--select`) will override the settings in _every_ resolved configuration file.
+
+Unlike [ESLint](https://eslint.org/docs/latest/user-guide/configuring/configuration-files#cascading-and-hierarchy),
+Ruff does not merge settings across configuration files; instead, the "closest" configuration file
+is used, and any parent configuration files are ignored. In lieu of this implicit cascade, Ruff
+supports an [`extend`](#extend) field, which allows you to inherit the settings from another
+`pyproject.toml` file, like so:
+
+```toml
+# Extend the `pyproject.toml` file in the parent directory.
+extend = "../pyproject.toml"
+# But use a different line length.
+line-length = 100
+```
+
+### Python file discovery
+
+When passed a path on the command-line, Ruff will automatically discover all Python files in that
+path, taking into account the [`exclude`](#exclude) and [`extend-exclude`](#extend-exclude) settings
+in each directory's `pyproject.toml` file.
+
+By default, Ruff will also skip any files that are omitted via `.ignore`, `.gitignore`,
+`.git/info/exclude`, and global `gitignore` files (see: [`respect-gitignore`](#respect-gitignore)).
+
+Files that are passed to `ruff` directly are always checked, regardless of the above criteria.
+For example, `ruff /path/to/excluded/file.py` will always check `file.py`.
+
 ### Ignoring errors
 
 To omit a lint check entirely, add it to the "ignore" list via [`ignore`](#ignore) or
@@ -566,6 +619,7 @@ For more, see [pyupgrade](https://pypi.org/project/pyupgrade/3.2.0/) on PyPI.
 | UP013 | ConvertTypedDictFunctionalToClass | Convert `...` from `TypedDict` functional to class syntax | 🛠 |
 | UP014 | ConvertNamedTupleFunctionalToClass | Convert `...` from `NamedTuple` functional to class syntax | 🛠 |
 | UP015 | RedundantOpenModes | Unnecessary open mode parameters | 🛠 |
+| UP016 | RemoveSixCompat | Unnecessary `six` compatibility usage | 🛠 |
 
 ### pep8-naming (N)
 
@@ -619,7 +673,7 @@ For more, see [flake8-annotations](https://pypi.org/project/flake8-annotations/2
 | ANN102 | MissingTypeCls | Missing type annotation for `...` in classmethod |  |
 | ANN201 | MissingReturnTypePublicFunction | Missing return type annotation for public function `...` |  |
 | ANN202 | MissingReturnTypePrivateFunction | Missing return type annotation for private function `...` |  |
-| ANN204 | MissingReturnTypeMagicMethod | Missing return type annotation for magic method `...` |  |
+| ANN204 | MissingReturnTypeSpecialMethod | Missing return type annotation for special method `...` | 🛠 |
 | ANN205 | MissingReturnTypeStaticMethod | Missing return type annotation for staticmethod `...` |  |
 | ANN206 | MissingReturnTypeClassMethod | Missing return type annotation for classmethod `...` |  |
 | ANN401 | DynamicallyTypedExpression | Dynamically typed expressions (typing.Any) are disallowed in `...` |  |
@@ -731,6 +785,16 @@ For more, see [flake8-debugger](https://pypi.org/project/flake8-debugger/4.1.2/)
 | ---- | ---- | ------- | --- |
 | T100 | Debugger | Import for `...` found |  |
 
+### flake8-errmsg (EM)
+
+For more, see [flake8-errmsg](https://pypi.org/project/flake8-errmsg/0.4.0/) on PyPI.
+
+| Code | Name | Message | Fix |
+| ---- | ---- | ------- | --- |
+| EM101 | RawStringInException | Exception must not use a string literal, assign to variable first |  |
+| EM102 | FStringInException | Exception must not use an f-string literal, assign to variable first |  |
+| EM103 | DotFormatInException | Exception must not use a `.format()` string directly, assign to variable first |  |
+
 ### flake8-import-conventions (ICN)
 
 | Code | Name | Message | Fix |
@@ -808,6 +872,25 @@ For more, see [eradicate](https://pypi.org/project/eradicate/2.1.0/) on PyPI.
 | ---- | ---- | ------- | --- |
 | ERA001 | CommentedOutCode | Found commented-out code | 🛠 |
 
+### pandas-vet (PDV)
+
+For more, see [pandas-vet](https://pypi.org/project/pandas-vet/0.2.3/) on PyPI.
+
+| Code | Name | Message | Fix |
+| ---- | ---- | ------- | --- |
+| PDV002 | UseOfInplaceArgument | `inplace=True` should be avoided; it has inconsistent behavior |  |
+| PDV003 | UseOfDotIsNull | `.isna` is preferred to `.isnull`; functionality is equivalent |  |
+| PDV004 | UseOfDotNotNull | `.notna` is preferred to `.notnull`; functionality is equivalent |  |
+| PDV007 | UseOfDotIx | ``ix` i` deprecated; use more explicit `.loc` o` `.iloc` |  |
+| PDV008 | UseOfDotAt | Use `.loc` instead of `.at`.  If speed is important, use numpy. |  |
+| PDV009 | UseOfDotIat | Use `.iloc` instea` of `.iat`.  If speed is important, use numpy. |  |
+| PDV010 | UseOfDotPivotOrUnstack | `.pivot_table` is preferred to `.pivot` or `.unstack`; provides same functionality |  |
+| PDV011 | UseOfDotValues | Use `.to_numpy()` instead of `.values` |  |
+| PDV012 | UseOfDotReadTable | `.read_csv` is preferred to `.read_table`; provides same functionality |  |
+| PDV013 | UseOfDotStack | `.melt` is preferred to `.stack`; provides same functionality |  |
+| PDV015 | UseOfPdMerge | Use `.merge` method instead of `pd.merge` function. They have equivalent functionality. |  |
+| PDV901 | DfIsABadVariableName | `df` is a bad variable name. Be kinder to your future self. |  |
+
 ### pygrep-hooks (PGH)
 
 For more, see [pygrep-hooks](https://github.com/pre-commit/pygrep-hooks) on GitHub.
@@ -1017,6 +1100,7 @@ natively, including:
 - [`flake8-debugger`](https://pypi.org/project/flake8-debugger/)
 - [`flake8-docstrings`](https://pypi.org/project/flake8-docstrings/)
 - [`flake8-eradicate`](https://pypi.org/project/flake8-eradicate/)
+- [`flake8-errmsg`](https://pypi.org/project/flake8-errmsg/)
 - [`flake8-import-conventions`](https://github.com/joaopalmeiro/flake8-import-conventions)
 - [`flake8-print`](https://pypi.org/project/flake8-print/)
 - [`flake8-quotes`](https://pypi.org/project/flake8-quotes/)
@@ -1039,8 +1123,7 @@ conflicts with the `isort` rules, like `I001`).
 
 Beyond the rule set, Ruff suffers from the following limitations vis-à-vis Flake8:
 
-1. Ruff does not yet support a few Python 3.9 and 3.10 language features, including structural
-   pattern matching and parenthesized context managers.
+1. Ruff does not yet support structural pattern matching.
 2. Flake8 has a plugin architecture and supports writing custom lint rules. (Instead, popular Flake8
    plugins are re-implemented in Rust as part of Ruff itself.)
 
@@ -1071,6 +1154,7 @@ Today, Ruff can be used to replace Flake8 when used with any of the following pl
 - [`flake8-debugger`](https://pypi.org/project/flake8-debugger/)
 - [`flake8-docstrings`](https://pypi.org/project/flake8-docstrings/)
 - [`flake8-eradicate`](https://pypi.org/project/flake8-eradicate/)
+- [`flake8-errmsg`](https://pypi.org/project/flake8-errmsg/)
 - [`flake8-import-conventions`](https://github.com/joaopalmeiro/flake8-import-conventions)
 - [`flake8-print`](https://pypi.org/project/flake8-print/)
 - [`flake8-quotes`](https://pypi.org/project/flake8-quotes/)
@@ -1422,7 +1506,7 @@ Exclusions are based on globs, and can be either:
   (to exclude any Python files in `directory`). Note that these paths are relative to the
   project root (e.g., the directory containing your `pyproject.toml`).
 
-Note that you'll typically want to use [`extend_exclude`](#extend_exclude) to modify
+Note that you'll typically want to use [`extend-exclude`](#extend-exclude) to modify
 the excluded paths.
 
 **Default value**: `[".bzr", ".direnv", ".eggs", ".git", ".hg", ".mypy_cache", ".nox", ".pants.d", ".ruff_cache", ".svn", ".tox", ".venv", "__pypackages__", "_build", "buck-out", "build", "dist", "node_modules", "venv"]`
@@ -1438,6 +1522,30 @@ exclude = [".venv"]
 
 ---
 
+#### [`extend`](#extend)
+
+A path to a local `pyproject.toml` file to merge into this configuration.
+
+To resolve the current `pyproject.toml` file, Ruff will first resolve this base
+configuration file, then merge in any properties defined in the current configuration
+file.
+
+**Default value**: `None`
+
+**Type**: `Path`
+
+**Example usage**:
+
+```toml
+[tool.ruff]
+# Extend the `pyproject.toml` file in the parent directory.
+extend = "../pyproject.toml"
+# But use a different line length.
+line-length = 100
+```
+
+---
+
 #### [`extend-exclude`](#extend-exclude)
 
 A list of file patterns to omit from linting, in addition to those specified by `exclude`.
@@ -1650,6 +1758,24 @@ any matching files.
 
 ---
 
+#### [`respect-gitignore`](#respect-gitignore)
+
+Whether to automatically exclude files that are ignored by `.ignore`, `.gitignore`,
+`.git/info/exclude`, and global `gitignore` files. Enabled by default.
+
+**Default value**: `true`
+
+**Type**: `bool`
+
+**Example usage**:
+
+```toml
+[tool.ruff]
+respect_gitignore = false
+```
+
+---
+
 #### [`select`](#select)
 
 A list of check code prefixes to enable. Prefixes can specify exact checks (like
@@ -1695,6 +1821,25 @@ show-source = true
 
 The source code paths to consider, e.g., when resolving first- vs. third-party imports.
 
+As an example: given a Python package structure like:
+
+```text
+my_package/
+  pyproject.toml
+  src/
+    my_package/
+      __init__.py
+      foo.py
+      bar.py
+```
+
+The `src` directory should be included in `source` (e.g., `source = ["src"]`), such that
+when resolving imports, `my_package.foo` is considered a first-party import.
+
+This field supports globs. For example, if you have a series of Python packages in
+a `python_modules` directory, `src = ["python_modules/*"]` would expand to incorporate
+all of the packages in that directory.
+
 **Default value**: `["."]`
 
 **Type**: `Vec<PathBuf>`
@@ -1844,6 +1989,25 @@ extend-immutable-calls = ["fastapi.Depends", "fastapi.Query"]
 
 ---
 
+### `flake8-errmsg`
+
+#### [`max-string-length`](#max-string-length)
+
+Maximum string length for string literals in exception messages.
+
+**Default value**: `0`
+
+**Type**: `usize`
+
+**Example usage**:
+
+```toml
+[tool.ruff.flake8-errmsg]
+max-string-length = 20
+```
+
+---
+
 ### `flake8-import-conventions`
 
 #### [`aliases`](#aliases)
@@ -1980,6 +2144,25 @@ ban-relative-imports = "all"
 
 ---
 
+### `flake8-unused-arguments`
+
+#### [`ignore-variadic-names`](#ignore-variadic-names)
+
+Whether to allow unused variadic arguments, like `*args` and `**kwargs`.
+
+**Default value**: `false`
+
+**Type**: `bool`
+
+**Example usage**:
+
+```toml
+[tool.ruff.flake8-unused-arguments]
+ignore-variadic-names = true
+```
+
+---
+
 ### `isort`
 
 #### [`combine-as-imports`](#combine-as-imports)

flake8_to_ruff/Cargo.lock

@@ -771,7 +771,7 @@ checksum = "0ce7134b9999ecaf8bcd65542e436736ef32ddca1b3e06094cb6ec5755203b80"
 
 [[package]]
 name = "flake8_to_ruff"
-version = "0.0.177"
+version = "0.0.185"
 dependencies = [
  "anyhow",
  "clap",
@@ -1975,7 +1975,7 @@ dependencies = [
 
 [[package]]
 name = "ruff"
-version = "0.0.177"
+version = "0.0.185"
 dependencies = [
  "anyhow",
  "bincode",
@@ -2028,7 +2028,7 @@ dependencies = [
 [[package]]
 name = "rustpython-ast"
 version = "0.1.0"
-source = "git+https://github.com/RustPython/RustPython.git?rev=2edd0d264c50c7807bcff03a52a6509e8b7f187f#2edd0d264c50c7807bcff03a52a6509e8b7f187f"
+source = "git+https://github.com/RustPython/RustPython.git?rev=8d879a53197f9c73062f6160410bdba796a71cbf#8d879a53197f9c73062f6160410bdba796a71cbf"
 dependencies = [
  "num-bigint",
  "rustpython-common",
@@ -2038,7 +2038,7 @@ dependencies = [
 [[package]]
 name = "rustpython-common"
 version = "0.0.0"
-source = "git+https://github.com/RustPython/RustPython.git?rev=2edd0d264c50c7807bcff03a52a6509e8b7f187f#2edd0d264c50c7807bcff03a52a6509e8b7f187f"
+source = "git+https://github.com/RustPython/RustPython.git?rev=8d879a53197f9c73062f6160410bdba796a71cbf#8d879a53197f9c73062f6160410bdba796a71cbf"
 dependencies = [
  "ascii",
  "cfg-if 1.0.0",
@@ -2061,7 +2061,7 @@ dependencies = [
 [[package]]
 name = "rustpython-compiler-core"
 version = "0.1.2"
-source = "git+https://github.com/RustPython/RustPython.git?rev=2edd0d264c50c7807bcff03a52a6509e8b7f187f#2edd0d264c50c7807bcff03a52a6509e8b7f187f"
+source = "git+https://github.com/RustPython/RustPython.git?rev=8d879a53197f9c73062f6160410bdba796a71cbf#8d879a53197f9c73062f6160410bdba796a71cbf"
 dependencies = [
  "bincode",
  "bitflags",
@@ -2078,7 +2078,7 @@ dependencies = [
 [[package]]
 name = "rustpython-parser"
 version = "0.1.2"
-source = "git+https://github.com/RustPython/RustPython.git?rev=2edd0d264c50c7807bcff03a52a6509e8b7f187f#2edd0d264c50c7807bcff03a52a6509e8b7f187f"
+source = "git+https://github.com/RustPython/RustPython.git?rev=8d879a53197f9c73062f6160410bdba796a71cbf#8d879a53197f9c73062f6160410bdba796a71cbf"
 dependencies = [
  "ahash",
  "anyhow",

flake8_to_ruff/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "flake8-to-ruff"
-version = "0.0.177-dev.0"
+version = "0.0.185-dev.0"
 edition = "2021"
 
 [lib]

flake8_to_ruff/src/converter.rs

@@ -7,7 +7,8 @@ use ruff::flake8_tidy_imports::settings::Strictness;
 use ruff::settings::options::Options;
 use ruff::settings::pyproject::Pyproject;
 use ruff::{
-    flake8_annotations, flake8_bugbear, flake8_quotes, flake8_tidy_imports, mccabe, pep8_naming,
+    flake8_annotations, flake8_bugbear, flake8_errmsg, flake8_quotes, flake8_tidy_imports, mccabe,
+    pep8_naming,
 };
 
 use crate::plugin::Plugin;
@@ -73,6 +74,7 @@ pub fn convert(
     let mut options = Options::default();
     let mut flake8_annotations = flake8_annotations::settings::Options::default();
     let mut flake8_bugbear = flake8_bugbear::settings::Options::default();
+    let mut flake8_errmsg = flake8_errmsg::settings::Options::default();
     let mut flake8_quotes = flake8_quotes::settings::Options::default();
     let mut flake8_tidy_imports = flake8_tidy_imports::settings::Options::default();
     let mut mccabe = mccabe::settings::Options::default();
@@ -194,6 +196,15 @@ pub fn convert(
                     Ok(max_complexity) => mccabe.max_complexity = Some(max_complexity),
                     Err(e) => eprintln!("Unable to parse '{key}' property: {e}"),
                 },
+                // flake8-errmsg
+                "errmsg-max-string-length" | "errmsg_max_string_length" => {
+                    match value.clone().parse::<usize>() {
+                        Ok(max_string_length) => {
+                            flake8_errmsg.max_string_length = Some(max_string_length);
+                        }
+                        Err(e) => eprintln!("Unable to parse '{key}' property: {e}"),
+                    }
+                }
                 // Unknown
                 _ => eprintln!("Skipping unsupported property: {key}"),
             }
@@ -209,6 +220,9 @@ pub fn convert(
     if flake8_bugbear != flake8_bugbear::settings::Options::default() {
         options.flake8_bugbear = Some(flake8_bugbear);
     }
+    if flake8_errmsg != flake8_errmsg::settings::Options::default() {
+        options.flake8_errmsg = Some(flake8_errmsg);
+    }
     if flake8_quotes != flake8_quotes::settings::Options::default() {
         options.flake8_quotes = Some(flake8_quotes);
     }
@@ -246,6 +260,7 @@ mod tests {
             allowed_confusables: None,
             dummy_variable_rgx: None,
             exclude: None,
+            extend: None,
             extend_exclude: None,
             extend_ignore: None,
             extend_select: None,
@@ -257,6 +272,7 @@ mod tests {
             ignore_init_module_imports: None,
             line_length: None,
             per_file_ignores: None,
+            respect_gitignore: None,
             select: Some(vec![
                 CheckCodePrefix::E,
                 CheckCodePrefix::F,
@@ -268,9 +284,11 @@ mod tests {
             unfixable: None,
             flake8_annotations: None,
             flake8_bugbear: None,
+            flake8_errmsg: None,
             flake8_quotes: None,
             flake8_tidy_imports: None,
             flake8_import_conventions: None,
+            flake8_unused_arguments: None,
             isort: None,
             mccabe: None,
             pep8_naming: None,
@@ -291,6 +309,7 @@ mod tests {
             allowed_confusables: None,
             dummy_variable_rgx: None,
             exclude: None,
+            extend: None,
             extend_exclude: None,
             extend_ignore: None,
             extend_select: None,
@@ -302,6 +321,7 @@ mod tests {
             ignore_init_module_imports: None,
             line_length: Some(100),
             per_file_ignores: None,
+            respect_gitignore: None,
             select: Some(vec![
                 CheckCodePrefix::E,
                 CheckCodePrefix::F,
@@ -313,9 +333,11 @@ mod tests {
             unfixable: None,
             flake8_annotations: None,
             flake8_bugbear: None,
+            flake8_errmsg: None,
             flake8_quotes: None,
             flake8_tidy_imports: None,
             flake8_import_conventions: None,
+            flake8_unused_arguments: None,
             isort: None,
             mccabe: None,
             pep8_naming: None,
@@ -336,6 +358,7 @@ mod tests {
             allowed_confusables: None,
             dummy_variable_rgx: None,
             exclude: None,
+            extend: None,
             extend_exclude: None,
             extend_ignore: None,
             extend_select: None,
@@ -347,6 +370,7 @@ mod tests {
             ignore_init_module_imports: None,
             line_length: Some(100),
             per_file_ignores: None,
+            respect_gitignore: None,
             select: Some(vec![
                 CheckCodePrefix::E,
                 CheckCodePrefix::F,
@@ -358,9 +382,11 @@ mod tests {
             unfixable: None,
             flake8_annotations: None,
             flake8_bugbear: None,
+            flake8_errmsg: None,
             flake8_quotes: None,
             flake8_tidy_imports: None,
             flake8_import_conventions: None,
+            flake8_unused_arguments: None,
             isort: None,
             mccabe: None,
             pep8_naming: None,
@@ -381,6 +407,7 @@ mod tests {
             allowed_confusables: None,
             dummy_variable_rgx: None,
             exclude: None,
+            extend: None,
             extend_exclude: None,
             extend_ignore: None,
             extend_select: None,
@@ -392,6 +419,7 @@ mod tests {
             ignore_init_module_imports: None,
             line_length: None,
             per_file_ignores: None,
+            respect_gitignore: None,
             select: Some(vec![
                 CheckCodePrefix::E,
                 CheckCodePrefix::F,
@@ -403,9 +431,11 @@ mod tests {
             unfixable: None,
             flake8_annotations: None,
             flake8_bugbear: None,
+            flake8_errmsg: None,
             flake8_quotes: None,
             flake8_tidy_imports: None,
             flake8_import_conventions: None,
+            flake8_unused_arguments: None,
             isort: None,
             mccabe: None,
             pep8_naming: None,
@@ -426,6 +456,7 @@ mod tests {
             allowed_confusables: None,
             dummy_variable_rgx: None,
             exclude: None,
+            extend: None,
             extend_exclude: None,
             extend_ignore: None,
             extend_select: None,
@@ -437,6 +468,7 @@ mod tests {
             ignore_init_module_imports: None,
             line_length: None,
             per_file_ignores: None,
+            respect_gitignore: None,
             select: Some(vec![
                 CheckCodePrefix::E,
                 CheckCodePrefix::F,
@@ -448,6 +480,7 @@ mod tests {
             unfixable: None,
             flake8_annotations: None,
             flake8_bugbear: None,
+            flake8_errmsg: None,
             flake8_quotes: Some(flake8_quotes::settings::Options {
                 inline_quotes: Some(flake8_quotes::settings::Quote::Single),
                 multiline_quotes: None,
@@ -456,6 +489,7 @@ mod tests {
             }),
             flake8_tidy_imports: None,
             flake8_import_conventions: None,
+            flake8_unused_arguments: None,
             isort: None,
             mccabe: None,
             pep8_naming: None,
@@ -479,6 +513,7 @@ mod tests {
             allowed_confusables: None,
             dummy_variable_rgx: None,
             exclude: None,
+            extend: None,
             extend_exclude: None,
             extend_ignore: None,
             extend_select: None,
@@ -490,6 +525,7 @@ mod tests {
             ignore_init_module_imports: None,
             line_length: None,
             per_file_ignores: None,
+            respect_gitignore: None,
             select: Some(vec![
                 CheckCodePrefix::D100,
                 CheckCodePrefix::D101,
@@ -537,9 +573,11 @@ mod tests {
             unfixable: None,
             flake8_annotations: None,
             flake8_bugbear: None,
+            flake8_errmsg: None,
             flake8_quotes: None,
             flake8_tidy_imports: None,
             flake8_import_conventions: None,
+            flake8_unused_arguments: None,
             isort: None,
             mccabe: None,
             pep8_naming: None,
@@ -560,6 +598,7 @@ mod tests {
             allowed_confusables: None,
             dummy_variable_rgx: None,
             exclude: None,
+            extend: None,
             extend_exclude: None,
             extend_ignore: None,
             extend_select: None,
@@ -571,6 +610,7 @@ mod tests {
             ignore_init_module_imports: None,
             line_length: None,
             per_file_ignores: None,
+            respect_gitignore: None,
             select: Some(vec![
                 CheckCodePrefix::E,
                 CheckCodePrefix::F,
@@ -583,6 +623,7 @@ mod tests {
             unfixable: None,
             flake8_annotations: None,
             flake8_bugbear: None,
+            flake8_errmsg: None,
             flake8_quotes: Some(flake8_quotes::settings::Options {
                 inline_quotes: Some(flake8_quotes::settings::Quote::Single),
                 multiline_quotes: None,
@@ -591,6 +632,7 @@ mod tests {
             }),
             flake8_tidy_imports: None,
             flake8_import_conventions: None,
+            flake8_unused_arguments: None,
             isort: None,
             mccabe: None,
             pep8_naming: None,

flake8_to_ruff/src/plugin.rs

@@ -14,6 +14,7 @@ pub enum Plugin {
     Flake8Comprehensions,
     Flake8Debugger,
     Flake8Docstrings,
+    Flake8ErrMsg,
     Flake8Eradicate,
     Flake8Print,
     Flake8Quotes,
@@ -21,6 +22,7 @@ pub enum Plugin {
     Flake8Simplify,
     Flake8TidyImports,
     McCabe,
+    PandasVet,
     PEP8Naming,
     Pyupgrade,
 }
@@ -39,12 +41,14 @@ impl FromStr for Plugin {
             "flake8-debugger" => Ok(Plugin::Flake8Debugger),
             "flake8-docstrings" => Ok(Plugin::Flake8Docstrings),
             "flake8-eradicate" => Ok(Plugin::Flake8BlindExcept),
+            "flake8-errmsg" => Ok(Plugin::Flake8ErrMsg),
             "flake8-print" => Ok(Plugin::Flake8Print),
             "flake8-quotes" => Ok(Plugin::Flake8Quotes),
             "flake8-return" => Ok(Plugin::Flake8Return),
             "flake8-simplify" => Ok(Plugin::Flake8Simplify),
             "flake8-tidy-imports" => Ok(Plugin::Flake8TidyImports),
             "mccabe" => Ok(Plugin::McCabe),
+            "pandas-vet" => Ok(Plugin::PandasVet),
             "pep8-naming" => Ok(Plugin::PEP8Naming),
             "pyupgrade" => Ok(Plugin::Pyupgrade),
             _ => Err(anyhow!("Unknown plugin: {string}")),
@@ -57,19 +61,24 @@ impl Plugin {
         match self {
             Plugin::Flake8Annotations => CheckCodePrefix::ANN,
             Plugin::Flake8Bandit => CheckCodePrefix::S,
+            // TODO(charlie): Handle rename of `B` to `BLE`.
             Plugin::Flake8BlindExcept => CheckCodePrefix::BLE,
             Plugin::Flake8Bugbear => CheckCodePrefix::B,
             Plugin::Flake8Builtins => CheckCodePrefix::A,
             Plugin::Flake8Comprehensions => CheckCodePrefix::C4,
             Plugin::Flake8Debugger => CheckCodePrefix::T1,
             Plugin::Flake8Docstrings => CheckCodePrefix::D,
+            // TODO(charlie): Handle rename of `E` to `ERA`.
             Plugin::Flake8Eradicate => CheckCodePrefix::ERA,
+            Plugin::Flake8ErrMsg => CheckCodePrefix::EM,
             Plugin::Flake8Print => CheckCodePrefix::T2,
             Plugin::Flake8Quotes => CheckCodePrefix::Q,
             Plugin::Flake8Return => CheckCodePrefix::RET,
             Plugin::Flake8Simplify => CheckCodePrefix::SIM,
             Plugin::Flake8TidyImports => CheckCodePrefix::I25,
             Plugin::McCabe => CheckCodePrefix::C9,
+            // TODO(charlie): Handle rename of `PD` to `PDV`.
+            Plugin::PandasVet => CheckCodePrefix::PDV,
             Plugin::PEP8Naming => CheckCodePrefix::N,
             Plugin::Pyupgrade => CheckCodePrefix::U,
         }
@@ -101,14 +110,16 @@ impl Plugin {
                 DocstringConvention::PEP8.select()
             }
             Plugin::Flake8Eradicate => vec![CheckCodePrefix::ERA],
+            Plugin::Flake8ErrMsg => vec![CheckCodePrefix::EM],
             Plugin::Flake8Print => vec![CheckCodePrefix::T2],
             Plugin::Flake8Quotes => vec![CheckCodePrefix::Q],
             Plugin::Flake8Return => vec![CheckCodePrefix::RET],
             Plugin::Flake8Simplify => vec![CheckCodePrefix::SIM],
-            Plugin::Flake8TidyImports => vec![CheckCodePrefix::I25],
+            Plugin::Flake8TidyImports => vec![CheckCodePrefix::TID],
             Plugin::McCabe => vec![CheckCodePrefix::C9],
+            Plugin::PandasVet => vec![CheckCodePrefix::PDV],
             Plugin::PEP8Naming => vec![CheckCodePrefix::N],
-            Plugin::Pyupgrade => vec![CheckCodePrefix::U],
+            Plugin::Pyupgrade => vec![CheckCodePrefix::UP],
         }
     }
 }
@@ -377,6 +388,9 @@ pub fn infer_plugins_from_options(flake8: &HashMap<String, Option<String>>) -> V
             "staticmethod-decorators" | "staticmethod_decorators" => {
                 plugins.insert(Plugin::PEP8Naming);
             }
+            "max-string-length" | "max_string_length" => {
+                plugins.insert(Plugin::Flake8ErrMsg);
+            }
             _ => {}
         }
     }
@@ -398,11 +412,13 @@ pub fn infer_plugins_from_codes(codes: &BTreeSet<CheckCodePrefix>) -> Vec<Plugin
         Plugin::Flake8Debugger,
         Plugin::Flake8Docstrings,
         Plugin::Flake8Eradicate,
+        Plugin::Flake8ErrMsg,
         Plugin::Flake8Print,
         Plugin::Flake8Quotes,
         Plugin::Flake8Return,
         Plugin::Flake8Simplify,
         Plugin::Flake8TidyImports,
+        Plugin::PandasVet,
         Plugin::PEP8Naming,
         Plugin::Pyupgrade,
     ]

resources/test/fixtures/README.md

@@ -0,0 +1,3 @@
+# fixtures
+
+Fixture files used for snapshot testing.

resources/test/fixtures/flake8_bugbear/B009_B010.py

@@ -20,6 +20,8 @@ getattr(foo, "_123abc")
 getattr(foo, "abc123")
 getattr(foo, r"abc123")
 _ = lambda x: getattr(x, "bar")
+if getattr(x, "bar"):
+    pass
 
 # Valid setattr usage
 setattr(foo, bar, None)
@@ -28,6 +30,8 @@ setattr(foo, "123abc", None)
 setattr(foo, r"123\abc", None)
 setattr(foo, "except", None)
 _ = lambda x: setattr(x, "bar", 1)
+if setattr(x, "bar", 1):
+    pass
 
 # Invalid usage
 setattr(foo, "bar", None)

resources/test/fixtures/flake8_errmsg/EM.py

@@ -0,0 +1,23 @@
+from __future__ import annotations
+
+
+def f_a():
+    raise RuntimeError("This is an example exception")
+
+
+def f_a_short():
+    raise RuntimeError("Error")
+
+
+def f_b():
+    example = "example"
+    raise RuntimeError(f"This is an {example} exception")
+
+
+def f_c():
+    raise RuntimeError("This is an {example} exception".format(example="example"))
+
+
+def f_ok():
+    msg = "hello"
+    raise RuntimeError(msg)

resources/test/fixtures/flake8_unused_arguments/ARG.py

@@ -27,7 +27,7 @@ def f(cls, x):
 lambda x: print("Hello, world!")
 
 
-class X:
+class C:
     ###
     # Unused arguments.
     ###

resources/test/fixtures/flake8_unused_arguments/ignore_variadic_names.py

@@ -0,0 +1,14 @@
+def f(a, b):
+    print("Hello, world!")
+
+
+def f(a, b, *args, **kwargs):
+    print("Hello, world!")
+
+
+class C:
+    def f(self, a, b):
+        print("Hello, world!")
+
+    def f(self, a, b, *args, **kwargs):
+        print("Hello, world!")

resources/test/fixtures/isort/leading_prefix.py

@@ -4,3 +4,10 @@ import os
 if True:
     x = 1; import sys
     import os
+
+if True:
+    x = 1; \
+        import os
+
+x = 1; \
+import os

resources/test/fixtures/pycodestyle/constant_literals.py

@@ -0,0 +1,39 @@
+###
+# Errors
+###
+if "abc" is "def":  # F632 (fix)
+    pass
+if "abc" is None:  # F632 (fix, but leaves behind unfixable E711)
+    pass
+if None is "abc":  # F632 (fix, but leaves behind unfixable E711)
+    pass
+if "abc" is False:  # F632 (fix, but leaves behind unfixable E712)
+    pass
+if False is "abc":  # F632 (fix, but leaves behind unfixable E712)
+    pass
+if False == None:  # E711, E712 (fix)
+    pass
+if None == False:  # E711, E712 (fix)
+    pass
+
+###
+# Unfixable errors
+###
+if "abc" == None:  # E711
+    pass
+if None == "abc":  # E711
+    pass
+if "abc" == False:  # E712
+    pass
+if False == "abc":  # E712
+    pass
+
+###
+# Non-errors
+###
+if "def" == "abc":
+    pass
+if False is None:
+    pass
+if None is False:
+    pass

resources/test/fixtures/pyflakes/F401_7.py

@@ -0,0 +1,16 @@
+"""Test: noqa directives."""
+
+from module import (
+    A,  # noqa: F401
+    B,
+)
+
+from module import (
+    A,  # noqa: F401
+    B,  # noqa: F401
+)
+
+from module import (
+    A,
+    B,
+)

resources/test/fixtures/pyflakes/F811_20.py

@@ -7,7 +7,6 @@ import fu
 
 
 class bar:
-    # STOPSHIP: This errors.
     fu = 1
 
 

resources/test/fixtures/pyflakes/F841_0.py

@@ -10,13 +10,13 @@ except ValueError as e:
     print(e)
 
 
-def f1():
+def f():
     x = 1
     y = 2
     z = x + y
 
 
-def f2():
+def f():
     foo = (1, 2)
     (a, b) = (1, 2)
 
@@ -26,12 +26,12 @@ def f2():
     (x, y) = baz = bar
 
 
-def f3():
+def f():
     locals()
     x = 1
 
 
-def f4():
+def f():
     _ = 1
     __ = 1
     _discarded = 1
@@ -40,26 +40,26 @@ def f4():
 a = 1
 
 
-def f5():
+def f():
     global a
 
-    # Used in `f7` via `nonlocal`.
+    # Used in `c` via `nonlocal`.
     b = 1
 
-    def f6():
+    def c():
         # F841
         b = 1
 
-    def f7():
+    def d():
         nonlocal b
 
 
-def f6():
+def f():
     annotations = []
     assert len([annotations for annotations in annotations])
 
 
-def f7():
+def f():
     def connect():
         return None, None
 
@@ -67,6 +67,22 @@ def f7():
         cursor.execute("SELECT * FROM users")
 
 
-def f8():
-    with open("file") as f, open("") as ((a, b)):
+def f():
+    def connect():
+        return None, None
+
+    with (connect() as (connection, cursor)):
+        cursor.execute("SELECT * FROM users")
+
+
+def f():
+    with open("file") as my_file, open("") as ((this, that)):
+        print("hello")
+
+
+def f():
+    with (
+        open("file") as my_file,
+        open("") as ((this, that)),
+    ):
         print("hello")

resources/test/fixtures/pyflakes/multi_statement_lines.py

@@ -0,0 +1,51 @@
+
+if True:
+    import foo; x = 1
+    import foo;     x = 1
+
+if True:
+    import foo; \
+x = 1
+
+if True:
+    import foo \
+        ; x = 1
+
+
+if True:
+    x = 1; import foo
+
+
+if True:
+    x = 1; \
+         import foo
+
+
+if True:
+    x = 1 \
+        ; import foo
+
+
+if True:
+    x = 1; import foo; x = 1
+    x = 1;     import foo;     x = 1
+
+if True:
+    x = 1; \
+        import foo; \
+    x = 1
+
+if True:
+    x = 1 \
+        ;import foo \
+        ;x = 1
+
+
+# Continuation, but not as the last content in the file.
+x = 1; \
+import foo
+
+# Continuation, followed by end-of-file. (Removing `import foo` would cause a syntax
+# error.)
+x = 1; \
+import foo

resources/test/fixtures/pyproject.toml

@@ -42,6 +42,9 @@ staticmethod-decorators = ["staticmethod"]
 [tool.ruff.flake8-tidy-imports]
 ban-relative-imports = "parents"
 
+[tool.ruff.flake8-errmsg]
+max-string-length = 20
+
 [tool.ruff.flake8-import-conventions.aliases]
 pandas = "pd"
 

resources/test/fixtures/pyupgrade/UP016.py

@@ -0,0 +1,87 @@
+# Replace names by built-in names, whether namespaced or not
+# https://github.com/search?q=%22from+six+import%22&type=code
+import six
+from six.moves import map  # No need
+from six import text_type
+
+six.text_type  # str
+six.binary_type  # bytes
+six.class_types  # (type,)
+six.string_types  # (str,)
+six.integer_types  # (int,)
+six.unichr  # chr
+six.iterbytes  # iter
+six.print_(...)  # print(...)
+six.exec_(c, g, l)  # exec(c, g, l)
+six.advance_iterator(it)  # next(it)
+six.next(it)  # next(it)
+six.callable(x)  # callable(x)
+six.moves.range(x)  # range(x)
+six.moves.xrange(x)  # range(x)
+isinstance(..., six.class_types)  # isinstance(..., type)
+issubclass(..., six.integer_types)  # issubclass(..., int)
+isinstance(..., six.string_types)  # isinstance(..., str)
+
+# Replace call on arg by method call on arg
+six.iteritems(dct)  # dct.items()
+six.iterkeys(dct)  # dct.keys()
+six.itervalues(dct)  # dct.values()
+six.viewitems(dct)  # dct.items()
+six.viewkeys(dct)  # dct.keys()
+six.viewvalues(dct)  # dct.values()
+six.assertCountEqual(self, a1, a2)  # self.assertCountEqual(a1, a2)
+six.assertRaisesRegex(self, e, r, fn)  # self.assertRaisesRegex(e, r, fn)
+six.assertRegex(self, s, r)  # self.assertRegex(s, r)
+
+# Replace call on arg by arg attribute
+six.get_method_function(meth)  # meth.__func__
+six.get_method_self(meth)  # meth.__self__
+six.get_function_closure(fn)  # fn.__closure__
+six.get_function_code(fn)  # fn.__code__
+six.get_function_defaults(fn)  # fn.__defaults__
+six.get_function_globals(fn)  # fn.__globals__
+
+# Replace by string literal
+six.b("...")  # b'...'
+six.u("...")  # '...'
+six.ensure_binary("...")  # b'...'
+six.ensure_str("...")  # '...'
+six.ensure_text("...")  # '...'
+six.b(string)  # no change
+
+# Replace by simple expression
+six.get_unbound_function(meth)  # meth
+six.create_unbound_method(fn, cls)  # fn
+
+# Raise exception
+six.raise_from(exc, exc_from)  # raise exc from exc_from
+six.reraise(tp, exc, tb)  # raise exc.with_traceback(tb)
+six.reraise(*sys.exc_info())  # raise
+
+# Int / Bytes conversion
+six.byte2int(bs)  # bs[0]
+six.indexbytes(bs, i)  # bs[i]
+six.int2byte(i)  # bytes((i, ))
+
+# Special cases for next calls
+next(six.iteritems(dct))  # next(iter(dct.items()))
+next(six.iterkeys(dct))  # next(iter(dct.keys()))
+next(six.itervalues(dct))  # next(iter(dct.values()))
+
+# TODO: To implement
+
+
+# Rewrite classes
+@six.python_2_unicode_compatible  # Remove
+class C(six.Iterator):
+    pass  # class C: pass
+
+
+class C(six.with_metaclass(M, B)):
+    pass  # class C(B, metaclass=M): pass
+
+
+# class C(B, metaclass=M): pass
+@six.add_metaclass(M)
+class C(B):
+    pass

resources/test/package/pyproject.toml

@@ -0,0 +1,2 @@
+[tool.ruff]
+src = ["."]

resources/test/package/src/package/app.py

@@ -0,0 +1,4 @@
+from package.core import method
+
+if __name__ == "__main__":
+    method()

resources/test/project/.gitignore

@@ -0,0 +1 @@
+examples/generated

resources/test/project/README.md

@@ -0,0 +1,89 @@
+# project
+
+An example multi-package Python project used to test setting resolution and other complex
+behaviors.
+
+## Expected behavior
+
+Running from the repo root should pick up and enforce the appropriate settings for each package:
+
+```
+∴ cargo run resources/test/project/
+Found 7 error(s).
+resources/test/project/examples/.dotfiles/script.py:1:1: I001 Import block is un-sorted or un-formatted
+resources/test/project/examples/.dotfiles/script.py:1:8: F401 `numpy` imported but unused
+resources/test/project/examples/.dotfiles/script.py:2:17: F401 `app.app_file` imported but unused
+resources/test/project/examples/docs/docs/file.py:1:1: I001 Import block is un-sorted or un-formatted
+resources/test/project/examples/docs/docs/file.py:8:5: F841 Local variable `x` is assigned to but never used
+resources/test/project/src/file.py:1:8: F401 `os` imported but unused
+resources/test/project/src/import_file.py:1:1: I001 Import block is un-sorted or un-formatted
+6 potentially fixable with the --fix option.
+```
+
+Running from the project directory itself should exhibit the same behavior:
+
+```
+∴ (cd resources/test/project/ && cargo run .)
+Found 7 error(s).
+examples/.dotfiles/script.py:1:1: I001 Import block is un-sorted or un-formatted
+examples/.dotfiles/script.py:1:8: F401 `numpy` imported but unused
+examples/.dotfiles/script.py:2:17: F401 `app.app_file` imported but unused
+examples/docs/docs/file.py:1:1: I001 Import block is un-sorted or un-formatted
+examples/docs/docs/file.py:8:5: F841 Local variable `x` is assigned to but never used
+src/file.py:1:8: F401 `os` imported but unused
+src/import_file.py:1:1: I001 Import block is un-sorted or un-formatted
+6 potentially fixable with the --fix option.
+```
+
+Running from the sub-package directory should exhibit the same behavior, but omit the top-level
+files:
+
+```
+∴ (cd resources/test/project/examples/docs && cargo run .)
+Found 2 error(s).
+docs/file.py:1:1: I001 Import block is un-sorted or un-formatted
+docs/file.py:8:5: F841 Local variable `x` is assigned to but never used
+1 potentially fixable with the --fix option.
+```
+
+`--config` should force Ruff to use the specified `pyproject.toml` for all files, and resolve
+file paths from the current working directory:
+
+```
+∴ (cargo run -- --config=resources/test/project/pyproject.toml resources/test/project/)
+Found 11 error(s).
+resources/test/project/examples/.dotfiles/script.py:1:1: I001 Import block is un-sorted or un-formatted
+resources/test/project/examples/.dotfiles/script.py:1:8: F401 `numpy` imported but unused
+resources/test/project/examples/.dotfiles/script.py:2:17: F401 `app.app_file` imported but unused
+resources/test/project/examples/docs/docs/concepts/file.py:1:8: F401 `os` imported but unused
+resources/test/project/examples/docs/docs/file.py:1:1: I001 Import block is un-sorted or un-formatted
+resources/test/project/examples/docs/docs/file.py:1:8: F401 `os` imported but unused
+resources/test/project/examples/docs/docs/file.py:3:8: F401 `numpy` imported but unused
+resources/test/project/examples/docs/docs/file.py:4:27: F401 `docs.concepts.file` imported but unused
+resources/test/project/examples/excluded/script.py:1:8: F401 `os` imported but unused
+resources/test/project/src/file.py:1:8: F401 `os` imported but unused
+resources/test/project/src/import_file.py:1:1: I001 Import block is un-sorted or un-formatted
+11 potentially fixable with the --fix option.
+```
+
+Running from a parent directory should this "ignore" the `exclude` (hence, `concepts/file.py` gets
+included in the output):
+
+```
+∴ (cd resources/test/project/examples && cargo run -- --config=docs/pyproject.toml .)
+Found 4 error(s).
+docs/docs/concepts/file.py:5:5: F841 Local variable `x` is assigned to but never used
+docs/docs/file.py:1:1: I001 Import block is un-sorted or un-formatted
+docs/docs/file.py:8:5: F841 Local variable `x` is assigned to but never used
+excluded/script.py:5:5: F841 Local variable `x` is assigned to but never used
+1 potentially fixable with the --fix option.
+```
+
+Passing an excluded directory directly should report errors in the contained files:
+
+```
+∴ cargo run resources/test/project/examples/excluded/
+Found 1 error(s).
+resources/test/project/examples/excluded/script.py:1:8: F401 `os` imported but unused
+1 potentially fixable with the --fix option.
+```

resources/test/project/examples/.dotfiles/script.py

@@ -0,0 +1,2 @@
+import numpy as np
+from app import app_file

resources/test/project/examples/docs/docs/concepts/file.py

@@ -0,0 +1,5 @@
+import os
+
+
+def f():
+    x = 1

resources/test/project/examples/docs/docs/file.py

@@ -0,0 +1,8 @@
+import os
+
+import numpy as np
+from docs.concepts import file
+
+
+def f():
+    x = 1

resources/test/project/examples/docs/pyproject.toml

@@ -0,0 +1,7 @@
+[tool.ruff]
+extend = "../../pyproject.toml"
+src = ["."]
+# Enable I001, and re-enable F841, to test extension priority.
+extend-select = ["I001", "F841"]
+extend-ignore = ["F401"]
+extend-exclude = ["./docs/concepts/file.py"]

resources/test/project/examples/excluded/script.py

@@ -0,0 +1,5 @@
+import os
+
+
+def f():
+    x = 1

resources/test/project/project/file.py

@@ -0,0 +1,5 @@
+import os
+
+
+def f():
+    x = 1

resources/test/project/project/import_file.py

@@ -0,0 +1,7 @@
+import numpy as np
+from app import app_file
+from core import core_file
+
+np.array([1, 2, 3])
+app_file()
+core_file()

resources/test/project/pyproject.toml

@@ -0,0 +1,5 @@
+[tool.ruff]
+src = [".", "python_modules/*"]
+exclude = ["examples/excluded"]
+extend-select = ["I001"]
+extend-ignore = ["F841"]

ruff_dev/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ruff_dev"
-version = "0.0.177"
+version = "0.0.185"
 edition = "2021"
 
 [dependencies]
@@ -11,8 +11,8 @@ itertools = { version = "0.10.5" }
 libcst = { git = "https://github.com/charliermarsh/LibCST", rev = "f2f0b7a487a8725d161fe8b3ed73a6758b21e177" }
 once_cell = { version = "1.16.0" }
 ruff = { path = ".." }
-rustpython-ast = { features = ["unparse"], git = "https://github.com/RustPython/RustPython.git", rev = "2edd0d264c50c7807bcff03a52a6509e8b7f187f" }
-rustpython-common = { git = "https://github.com/RustPython/RustPython.git", rev = "2edd0d264c50c7807bcff03a52a6509e8b7f187f" }
-rustpython-parser = { features = ["lalrpop"], git = "https://github.com/RustPython/RustPython.git", rev = "2edd0d264c50c7807bcff03a52a6509e8b7f187f" }
+rustpython-ast = { features = ["unparse"], git = "https://github.com/RustPython/RustPython.git", rev = "8d879a53197f9c73062f6160410bdba796a71cbf" }
+rustpython-common = { git = "https://github.com/RustPython/RustPython.git", rev = "8d879a53197f9c73062f6160410bdba796a71cbf" }
+rustpython-parser = { features = ["lalrpop"], git = "https://github.com/RustPython/RustPython.git", rev = "8d879a53197f9c73062f6160410bdba796a71cbf" }
 strum = { version = "0.24.1", features = ["strum_macros"] }
 strum_macros = { version = "0.24.3" }

ruff_macros/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ruff_macros"
-version = "0.0.177"
+version = "0.0.185"
 edition = "2021"
 
 [lib]

src/ast/helpers.rs

@@ -1,13 +1,26 @@
+use log::error;
 use once_cell::sync::Lazy;
 use regex::Regex;
 use rustc_hash::{FxHashMap, FxHashSet};
 use rustpython_ast::{
-    Arguments, Excepthandler, ExcepthandlerKind, Expr, ExprKind, Location, Stmt, StmtKind,
+    Arguments, Constant, Excepthandler, ExcepthandlerKind, Expr, ExprKind, Location, Stmt, StmtKind,
 };
+use rustpython_parser::lexer;
+use rustpython_parser::lexer::Tok;
 
 use crate::ast::types::Range;
 use crate::SourceCodeLocator;
 
+/// Create an `Expr` with default location from an `ExprKind`.
+pub fn create_expr(node: ExprKind) -> Expr {
+    Expr::new(Location::default(), Location::default(), node)
+}
+
+/// Create a `Stmt` with a default location from a `StmtKind`.
+pub fn create_stmt(node: StmtKind) -> Stmt {
+    Stmt::new(Location::default(), Location::default(), node)
+}
+
 fn collect_call_path_inner<'a>(expr: &'a Expr, parts: &mut Vec<&'a str>) {
     match &expr.node {
         ExprKind::Call { func, .. } => {
@@ -149,15 +162,12 @@ pub fn match_call_path(
 
 static DUNDER_REGEX: Lazy<Regex> = Lazy::new(|| Regex::new(r"__[^\s]+__").unwrap());
 
-pub fn is_assignment_to_a_dunder(node: &StmtKind) -> bool {
+/// Return `true` if the `Stmt` is an assignment to a dunder (like `__all__`).
+pub fn is_assignment_to_a_dunder(stmt: &Stmt) -> bool {
     // Check whether it's an assignment to a dunder, with or without a type
     // annotation. This is what pycodestyle (as of 2.9.1) does.
-    match node {
-        StmtKind::Assign {
-            targets,
-            value: _,
-            type_comment: _,
-        } => {
+    match &stmt.node {
+        StmtKind::Assign { targets, .. } => {
             if targets.len() != 1 {
                 return false;
             }
@@ -166,12 +176,7 @@ pub fn is_assignment_to_a_dunder(node: &StmtKind) -> bool {
                 _ => false,
             }
         }
-        StmtKind::AnnAssign {
-            target,
-            annotation: _,
-            value: _,
-            simple: _,
-        } => match &target.node {
+        StmtKind::AnnAssign { target, .. } => match &target.node {
             ExprKind::Name { id, ctx: _ } => DUNDER_REGEX.is_match(id),
             _ => false,
         },
@@ -179,6 +184,32 @@ pub fn is_assignment_to_a_dunder(node: &StmtKind) -> bool {
     }
 }
 
+/// Return `true` if the `Expr` is a singleton (`None`, `True`, `False`, or
+/// `...`).
+pub fn is_singleton(expr: &Expr) -> bool {
+    matches!(
+        expr.node,
+        ExprKind::Constant {
+            value: Constant::None | Constant::Bool(_) | Constant::Ellipsis,
+            ..
+        }
+    )
+}
+
+/// Return `true` if the `Expr` is a constant or tuple of constants.
+pub fn is_constant(expr: &Expr) -> bool {
+    match &expr.node {
+        ExprKind::Constant { .. } => true,
+        ExprKind::Tuple { elts, .. } => elts.iter().all(is_constant),
+        _ => false,
+    }
+}
+
+/// Return `true` if the `Expr` is a non-singleton constant.
+pub fn is_constant_non_singleton(expr: &Expr) -> bool {
+    is_constant(expr) && !is_singleton(expr)
+}
+
 /// Extract the names of all handled exceptions.
 pub fn extract_handler_names(handlers: &[Excepthandler]) -> Vec<Vec<&str>> {
     let mut handler_names = vec![];
@@ -229,7 +260,6 @@ pub fn collect_arg_names<'a>(arguments: &'a Arguments) -> FxHashSet<&'a str> {
 
 /// Returns `true` if a call is an argumented `super` invocation.
 pub fn is_super_call_with_arguments(func: &Expr, args: &[Expr]) -> bool {
-    // Check: is this a `super` call?
     if let ExprKind::Name { id, .. } = &func.node {
         id == "super" && !args.is_empty()
     } else {
@@ -311,13 +341,75 @@ pub fn count_trailing_lines(stmt: &Stmt, locator: &SourceCodeLocator) -> usize {
         .count()
 }
 
+/// Return the appropriate visual `Range` for any message that spans a `Stmt`.
+/// Specifically, this method returns the range of a function or class name,
+/// rather than that of the entire function or class body.
+pub fn identifier_range(stmt: &Stmt, locator: &SourceCodeLocator) -> Range {
+    if matches!(
+        stmt.node,
+        StmtKind::ClassDef { .. }
+            | StmtKind::FunctionDef { .. }
+            | StmtKind::AsyncFunctionDef { .. }
+    ) {
+        let contents = locator.slice_source_code_range(&Range::from_located(stmt));
+        for (start, tok, end) in lexer::make_tokenizer(&contents).flatten() {
+            if matches!(tok, Tok::Name { .. }) {
+                let start = to_absolute(start, stmt.location);
+                let end = to_absolute(end, stmt.location);
+                return Range {
+                    location: start,
+                    end_location: end,
+                };
+            }
+        }
+        error!("Failed to find identifier for {:?}", stmt);
+    }
+    Range::from_located(stmt)
+}
+
+/// Return `true` if a `Stmt` appears to be part of a multi-statement line, with
+/// other statements preceding it.
+pub fn preceded_by_continuation(stmt: &Stmt, locator: &SourceCodeLocator) -> bool {
+    // Does the previous line end in a continuation? This will have a specific
+    // false-positive, which is that if the previous line ends in a comment, it
+    // will be treated as a continuation. So we should only use this information to
+    // make conservative choices.
+    // TODO(charlie): Come up with a more robust strategy.
+    if stmt.location.row() > 1 {
+        let range = Range {
+            location: Location::new(stmt.location.row() - 1, 0),
+            end_location: Location::new(stmt.location.row(), 0),
+        };
+        let line = locator.slice_source_code_range(&range);
+        if line.trim().ends_with('\\') {
+            return true;
+        }
+    }
+    false
+}
+
+/// Return `true` if a `Stmt` appears to be part of a multi-statement line, with
+/// other statements preceding it.
+pub fn preceded_by_multi_statement_line(stmt: &Stmt, locator: &SourceCodeLocator) -> bool {
+    match_leading_content(stmt, locator) || preceded_by_continuation(stmt, locator)
+}
+
+/// Return `true` if a `Stmt` appears to be part of a multi-statement line, with
+/// other statements following it.
+pub fn followed_by_multi_statement_line(stmt: &Stmt, locator: &SourceCodeLocator) -> bool {
+    match_trailing_content(stmt, locator)
+}
+
 #[cfg(test)]
 mod tests {
     use anyhow::Result;
     use rustc_hash::{FxHashMap, FxHashSet};
+    use rustpython_ast::Location;
     use rustpython_parser::parser;
 
-    use crate::ast::helpers::match_module_member;
+    use crate::ast::helpers::{identifier_range, match_module_member, match_trailing_content};
+    use crate::ast::types::Range;
+    use crate::source_code_locator::SourceCodeLocator;
 
     #[test]
     fn builtin() -> Result<()> {
@@ -461,4 +553,130 @@ mod tests {
         ));
         Ok(())
     }
+
+    #[test]
+    fn trailing_content() -> Result<()> {
+        let contents = "x = 1";
+        let program = parser::parse_program(contents, "<filename>")?;
+        let stmt = program.first().unwrap();
+        let locator = SourceCodeLocator::new(contents);
+        assert!(!match_trailing_content(stmt, &locator));
+
+        let contents = "x = 1; y = 2";
+        let program = parser::parse_program(contents, "<filename>")?;
+        let stmt = program.first().unwrap();
+        let locator = SourceCodeLocator::new(contents);
+        assert!(match_trailing_content(stmt, &locator));
+
+        let contents = "x = 1  ";
+        let program = parser::parse_program(contents, "<filename>")?;
+        let stmt = program.first().unwrap();
+        let locator = SourceCodeLocator::new(contents);
+        assert!(!match_trailing_content(stmt, &locator));
+
+        let contents = "x = 1  # Comment";
+        let program = parser::parse_program(contents, "<filename>")?;
+        let stmt = program.first().unwrap();
+        let locator = SourceCodeLocator::new(contents);
+        assert!(!match_trailing_content(stmt, &locator));
+
+        let contents = r#"
+x = 1
+y = 2
+"#
+        .trim();
+        let program = parser::parse_program(contents, "<filename>")?;
+        let stmt = program.first().unwrap();
+        let locator = SourceCodeLocator::new(contents);
+        assert!(!match_trailing_content(stmt, &locator));
+
+        Ok(())
+    }
+
+    #[test]
+    fn extract_identifier_range() -> Result<()> {
+        let contents = "def f(): pass".trim();
+        let program = parser::parse_program(contents, "<filename>")?;
+        let stmt = program.first().unwrap();
+        let locator = SourceCodeLocator::new(contents);
+        assert_eq!(
+            identifier_range(stmt, &locator),
+            Range {
+                location: Location::new(1, 4),
+                end_location: Location::new(1, 5),
+            }
+        );
+
+        let contents = r#"
+def \
+  f():
+  pass
+"#
+        .trim();
+        let program = parser::parse_program(contents, "<filename>")?;
+        let stmt = program.first().unwrap();
+        let locator = SourceCodeLocator::new(contents);
+        assert_eq!(
+            identifier_range(stmt, &locator),
+            Range {
+                location: Location::new(2, 2),
+                end_location: Location::new(2, 3),
+            }
+        );
+
+        let contents = "class Class(): pass".trim();
+        let program = parser::parse_program(contents, "<filename>")?;
+        let stmt = program.first().unwrap();
+        let locator = SourceCodeLocator::new(contents);
+        assert_eq!(
+            identifier_range(stmt, &locator),
+            Range {
+                location: Location::new(1, 6),
+                end_location: Location::new(1, 11),
+            }
+        );
+
+        let contents = "class Class: pass".trim();
+        let program = parser::parse_program(contents, "<filename>")?;
+        let stmt = program.first().unwrap();
+        let locator = SourceCodeLocator::new(contents);
+        assert_eq!(
+            identifier_range(stmt, &locator),
+            Range {
+                location: Location::new(1, 6),
+                end_location: Location::new(1, 11),
+            }
+        );
+
+        let contents = r#"
+@decorator()
+class Class():
+  pass
+"#
+        .trim();
+        let program = parser::parse_program(contents, "<filename>")?;
+        let stmt = program.first().unwrap();
+        let locator = SourceCodeLocator::new(contents);
+        assert_eq!(
+            identifier_range(stmt, &locator),
+            Range {
+                location: Location::new(2, 6),
+                end_location: Location::new(2, 11),
+            }
+        );
+
+        let contents = r#"x = y + 1"#.trim();
+        let program = parser::parse_program(contents, "<filename>")?;
+        let stmt = program.first().unwrap();
+        let locator = SourceCodeLocator::new(contents);
+        assert_eq!(
+            identifier_range(stmt, &locator),
+            Range {
+                location: Location::new(1, 0),
+                end_location: Location::new(1, 9),
+            }
+        );
+
+        Ok(())
+    }
 }

src/ast/whitespace.rs

@@ -4,7 +4,7 @@ use std::str::Lines;
 use rustpython_ast::{Located, Location};
 
 use crate::ast::types::Range;
-use crate::check_ast::Checker;
+use crate::checkers::ast::Checker;
 
 /// Extract the leading indentation from a line.
 pub fn indentation<'a, T>(checker: &'a Checker, located: &'a Located<T>) -> Cow<'a, str> {

src/autofix/fixer.rs

@@ -10,7 +10,7 @@ use crate::autofix::Fix;
 use crate::checks::Check;
 use crate::source_code_locator::SourceCodeLocator;
 
-#[derive(Hash)]
+#[derive(Debug, Copy, Clone, Hash)]
 pub enum Mode {
     Generate,
     Apply,
@@ -27,15 +27,6 @@ impl From<bool> for Mode {
     }
 }
 
-impl From<&Mode> for bool {
-    fn from(value: &Mode) -> Self {
-        match value {
-            Mode::Generate | Mode::Apply => true,
-            Mode::None => false,
-        }
-    }
-}
-
 /// Auto-fix errors in a file, and write the fixed source code to disk.
 pub fn fix_file<'a>(
     checks: &'a [Check],

src/autofix/helpers.rs

@@ -2,7 +2,11 @@ use anyhow::{bail, Result};
 use itertools::Itertools;
 use rustpython_parser::ast::{ExcepthandlerKind, Location, Stmt, StmtKind};
 
+use crate::ast::helpers;
+use crate::ast::helpers::to_absolute;
+use crate::ast::whitespace::LinesWithTrailingNewline;
 use crate::autofix::Fix;
+use crate::source_code_locator::SourceCodeLocator;
 
 /// Determine if a body contains only a single statement, taking into account
 /// deleted.
@@ -66,7 +70,87 @@ fn is_lone_child(child: &Stmt, parent: &Stmt, deleted: &[&Stmt]) -> Result<bool>
     }
 }
 
-pub fn remove_stmt(stmt: &Stmt, parent: Option<&Stmt>, deleted: &[&Stmt]) -> Result<Fix> {
+/// Return the location of a trailing semicolon following a `Stmt`, if it's part
+/// of a multi-statement line.
+fn trailing_semicolon(stmt: &Stmt, locator: &SourceCodeLocator) -> Option<Location> {
+    let contents = locator.slice_source_code_at(&stmt.end_location.unwrap());
+    for (row, line) in LinesWithTrailingNewline::from(&contents).enumerate() {
+        let trimmed = line.trim();
+        if trimmed.starts_with(';') {
+            let column = line
+                .char_indices()
+                .find_map(|(column, char)| if char == ';' { Some(column) } else { None })
+                .unwrap();
+            return Some(to_absolute(
+                Location::new(row + 1, column),
+                stmt.end_location.unwrap(),
+            ));
+        }
+        if !trimmed.starts_with('\\') {
+            break;
+        }
+    }
+    None
+}
+
+/// Find the next valid break for a `Stmt` after a semicolon.
+fn next_stmt_break(semicolon: Location, locator: &SourceCodeLocator) -> Location {
+    let start_location = Location::new(semicolon.row(), semicolon.column() + 1);
+    let contents = locator.slice_source_code_at(&start_location);
+    for (row, line) in LinesWithTrailingNewline::from(&contents).enumerate() {
+        let trimmed = line.trim();
+        // Skip past any continuations.
+        if trimmed.starts_with('\\') {
+            continue;
+        }
+        return if trimmed.is_empty() {
+            // If the line is empty, then despite the previous statement ending in a
+            // semicolon, we know that it's not a multi-statement line.
+            to_absolute(Location::new(row + 1, 0), start_location)
+        } else {
+            // Otherwise, find the start of the next statement. (Or, anything that isn't
+            // whitespace.)
+            let column = line
+                .char_indices()
+                .find_map(|(column, char)| {
+                    if char.is_whitespace() {
+                        None
+                    } else {
+                        Some(column)
+                    }
+                })
+                .unwrap();
+            to_absolute(Location::new(row + 1, column), start_location)
+        };
+    }
+    Location::new(start_location.row() + 1, 0)
+}
+
+/// Return `true` if a `Stmt` occurs at the end of a file.
+fn is_end_of_file(stmt: &Stmt, locator: &SourceCodeLocator) -> bool {
+    let contents = locator.slice_source_code_at(&stmt.end_location.unwrap());
+    contents.is_empty()
+}
+
+/// Return the `Fix` to use when deleting a `Stmt`.
+///
+/// In some cases, this is as simple as deleting the `Range` of the `Stmt`
+/// itself. However, there are a few exceptions:
+/// - If the `Stmt` is _not_ the terminal statement in a multi-statement line,
+///   we need to delete up to the start of the next statement (and avoid
+///   deleting any content that precedes the statement).
+/// - If the `Stmt` is the terminal statement in a multi-statement line, we need
+///   to avoid deleting any content that precedes the statement.
+/// - If the `Stmt` has no trailing and leading content, then it's convenient to
+///   remove the entire start and end lines.
+/// - If the `Stmt` is the last statement in its parent body, replace it with a
+///   `pass` instead.
+pub fn delete_stmt(
+    stmt: &Stmt,
+    parent: Option<&Stmt>,
+    deleted: &[&Stmt],
+    locator: &SourceCodeLocator,
+) -> Result<Fix> {
     if parent
         .map(|parent| is_lone_child(stmt, parent, deleted))
         .map_or(Ok(None), |v| v.map(Some))?
@@ -80,12 +164,103 @@ pub fn remove_stmt(stmt: &Stmt, parent: Option<&Stmt>, deleted: &[&Stmt]) -> Res
             stmt.end_location.unwrap(),
         ))
     } else {
-        // Otherwise, nuke the entire line.
-        // TODO(charlie): This logic assumes that there are no multi-statement physical
-        // lines.
-        Ok(Fix::deletion(
-            Location::new(stmt.location.row(), 0),
-            Location::new(stmt.end_location.unwrap().row() + 1, 0),
-        ))
+        Ok(if let Some(semicolon) = trailing_semicolon(stmt, locator) {
+            let next = next_stmt_break(semicolon, locator);
+            Fix::deletion(stmt.location, next)
+        } else if helpers::match_leading_content(stmt, locator) {
+            Fix::deletion(stmt.location, stmt.end_location.unwrap())
+        } else if helpers::preceded_by_continuation(stmt, locator) {
+            if is_end_of_file(stmt, locator) && stmt.location.column() == 0 {
+                // Special-case: a file can't end in a continuation.
+                Fix::replacement("\n".to_string(), stmt.location, stmt.end_location.unwrap())
+            } else {
+                Fix::deletion(stmt.location, stmt.end_location.unwrap())
+            }
+        } else {
+            Fix::deletion(
+                Location::new(stmt.location.row(), 0),
+                Location::new(stmt.end_location.unwrap().row() + 1, 0),
+            )
+        })
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use anyhow::Result;
+    use rustpython_ast::Location;
+    use rustpython_parser::parser;
+
+    use crate::autofix::helpers::{next_stmt_break, trailing_semicolon};
+    use crate::source_code_locator::SourceCodeLocator;
+
+    #[test]
+    fn find_semicolon() -> Result<()> {
+        let contents = "x = 1";
+        let program = parser::parse_program(contents, "<filename>")?;
+        let stmt = program.first().unwrap();
+        let locator = SourceCodeLocator::new(contents);
+        assert_eq!(trailing_semicolon(stmt, &locator), None);
+
+        let contents = "x = 1; y = 1";
+        let program = parser::parse_program(contents, "<filename>")?;
+        let stmt = program.first().unwrap();
+        let locator = SourceCodeLocator::new(contents);
+        assert_eq!(
+            trailing_semicolon(stmt, &locator),
+            Some(Location::new(1, 5))
+        );
+
+        let contents = "x = 1 ; y = 1";
+        let program = parser::parse_program(contents, "<filename>")?;
+        let stmt = program.first().unwrap();
+        let locator = SourceCodeLocator::new(contents);
+        assert_eq!(
+            trailing_semicolon(stmt, &locator),
+            Some(Location::new(1, 6))
+        );
+
+        let contents = r#"
+x = 1 \
+  ; y = 1
+"#
+        .trim();
+        let program = parser::parse_program(contents, "<filename>")?;
+        let stmt = program.first().unwrap();
+        let locator = SourceCodeLocator::new(contents);
+        assert_eq!(
+            trailing_semicolon(stmt, &locator),
+            Some(Location::new(2, 2))
+        );
+
+        Ok(())
+    }
+
+    #[test]
+    fn find_next_stmt_break() {
+        let contents = "x = 1; y = 1";
+        let locator = SourceCodeLocator::new(contents);
+        assert_eq!(
+            next_stmt_break(Location::new(1, 4), &locator),
+            Location::new(1, 5)
+        );
+
+        let contents = "x = 1 ; y = 1";
+        let locator = SourceCodeLocator::new(contents);
+        assert_eq!(
+            next_stmt_break(Location::new(1, 5), &locator),
+            Location::new(1, 6)
+        );
+
+        let contents = r#"
+x = 1 \
+  ; y = 1
+"#
+        .trim();
+        let locator = SourceCodeLocator::new(contents);
+        assert_eq!(
+            next_stmt_break(Location::new(2, 2), &locator),
+            Location::new(2, 4)
+        );
     }
 }

src/autofix/mod.rs

@@ -35,12 +35,4 @@ impl Fix {
             end_location: at,
         }
     }
-
-    pub fn dummy(location: Location) -> Self {
-        Self {
-            content: String::new(),
-            location,
-            end_location: location,
-        }
-    }
 }

src/cache.rs

@@ -13,7 +13,7 @@ use serde::{Deserialize, Serialize};
 
 use crate::autofix::fixer;
 use crate::message::Message;
-use crate::settings::Settings;
+use crate::settings::{flags, Settings};
 
 const CARGO_PKG_VERSION: &str = env!("CARGO_PKG_VERSION");
 
@@ -34,43 +34,6 @@ struct CheckResult {
     messages: Vec<Message>,
 }
 
-pub enum Mode {
-    ReadWrite,
-    ReadOnly,
-    WriteOnly,
-    None,
-}
-
-impl Mode {
-    fn allow_read(&self) -> bool {
-        match self {
-            Mode::ReadWrite => true,
-            Mode::ReadOnly => true,
-            Mode::WriteOnly => false,
-            Mode::None => false,
-        }
-    }
-
-    fn allow_write(&self) -> bool {
-        match self {
-            Mode::ReadWrite => true,
-            Mode::ReadOnly => false,
-            Mode::WriteOnly => true,
-            Mode::None => false,
-        }
-    }
-}
-
-impl From<bool> for Mode {
-    fn from(value: bool) -> Self {
-        if value {
-            Mode::ReadWrite
-        } else {
-            Mode::None
-        }
-    }
-}
-
 fn cache_dir() -> &'static str {
     "./.ruff_cache"
 }
@@ -79,10 +42,10 @@ fn content_dir() -> &'static str {
     "content"
 }
 
-fn cache_key(path: &Path, settings: &Settings, autofix: &fixer::Mode) -> u64 {
+fn cache_key<P: AsRef<Path>>(path: P, settings: &Settings, autofix: fixer::Mode) -> u64 {
     let mut hasher = DefaultHasher::new();
     CARGO_PKG_VERSION.hash(&mut hasher);
-    path.absolutize().unwrap().hash(&mut hasher);
+    path.as_ref().absolutize().unwrap().hash(&mut hasher);
     settings.hash(&mut hasher);
     autofix.hash(&mut hasher);
     hasher.finish()
@@ -128,14 +91,14 @@ fn read_sync(key: u64) -> Result<Vec<u8>, std::io::Error> {
 }
 
 /// Get a value from the cache.
-pub fn get(
-    path: &Path,
+pub fn get<P: AsRef<Path>>(
+    path: P,
     metadata: &Metadata,
     settings: &Settings,
-    autofix: &fixer::Mode,
-    mode: &Mode,
+    autofix: fixer::Mode,
+    cache: flags::Cache,
 ) -> Option<Vec<Message>> {
-    if !mode.allow_read() {
+    if matches!(cache, flags::Cache::Disabled) {
         return None;
     };
 
@@ -157,15 +120,15 @@ pub fn get(
 }
 
 /// Set a value in the cache.
-pub fn set(
-    path: &Path,
+pub fn set<P: AsRef<Path>>(
+    path: P,
     metadata: &Metadata,
     settings: &Settings,
-    autofix: &fixer::Mode,
+    autofix: fixer::Mode,
     messages: &[Message],
-    mode: &Mode,
+    cache: flags::Cache,
 ) {
-    if !mode.allow_write() {
+    if matches!(cache, flags::Cache::Disabled) {
         return;
     };
 

src/check_lines.rs

@@ -1,288 +0,0 @@
-//! Lint rules based on checking raw physical lines.
-
-use nohash_hasher::IntMap;
-use once_cell::sync::Lazy;
-use regex::Regex;
-use rustpython_parser::ast::Location;
-
-use crate::ast::types::Range;
-use crate::autofix::Fix;
-use crate::checks::{Check, CheckCode, CheckKind, CODE_REDIRECTS};
-use crate::noqa;
-use crate::noqa::{is_file_exempt, Directive};
-use crate::settings::Settings;
-
-// Regex from PEP263.
-static CODING_COMMENT_REGEX: Lazy<Regex> =
-    Lazy::new(|| Regex::new(r"^[ \t\f]*#.*?coding[:=][ \t]*utf-?8").unwrap());
-
-static URL_REGEX: Lazy<Regex> = Lazy::new(|| Regex::new(r"^https?://\S+$").unwrap());
-
-/// Whether the given line is too long and should be reported.
-fn should_enforce_line_length(line: &str, length: usize, limit: usize) -> bool {
-    if length <= limit {
-        return false;
-    }
-    let mut chunks = line.split_whitespace();
-    let (Some(first), Some(_)) = (chunks.next(), chunks.next()) else {
-        // Single word / no printable chars - no way to make the line shorter
-        return false;
-    };
-
-    // Do not enforce the line length for commented lines that end with a URL
-    // or contain only a single word.
-    !(first == "#" && chunks.last().map_or(true, |c| URL_REGEX.is_match(c)))
-}
-
-pub fn check_lines(
-    checks: &mut Vec<Check>,
-    contents: &str,
-    noqa_line_for: &IntMap<usize, usize>,
-    settings: &Settings,
-    autofix: bool,
-    ignore_noqa: bool,
-) {
-    let enforce_unnecessary_coding_comment = settings.enabled.contains(&CheckCode::UP009);
-    let enforce_line_too_long = settings.enabled.contains(&CheckCode::E501);
-    let enforce_noqa = settings.enabled.contains(&CheckCode::RUF100);
-
-    let mut noqa_directives: IntMap<usize, (Directive, Vec<&str>)> = IntMap::default();
-    let mut line_checks = vec![];
-    let mut ignored = vec![];
-
-    checks.sort_by_key(|check| check.location);
-    let mut checks_iter = checks.iter().enumerate().peekable();
-    if let Some((_index, check)) = checks_iter.peek() {
-        assert!(check.location.row() >= 1);
-    }
-
-    macro_rules! add_if {
-        ($check:expr, $noqa_lineno:expr, $line:expr) => {{
-            match noqa_directives
-                .entry($noqa_lineno)
-                .or_insert_with(|| (noqa::extract_noqa_directive($line), vec![]))
-            {
-                (Directive::All(..), matches) => {
-                    matches.push($check.kind.code().as_ref());
-                    if ignore_noqa {
-                        line_checks.push($check);
-                    }
-                }
-                (Directive::Codes(.., codes), matches) => {
-                    if noqa::includes($check.kind.code(), codes) {
-                        matches.push($check.kind.code().as_ref());
-                        if ignore_noqa {
-                            line_checks.push($check);
-                        }
-                    } else {
-                        line_checks.push($check);
-                    }
-                }
-                (Directive::None, ..) => line_checks.push($check),
-            }
-        }};
-    }
-
-    let lines: Vec<&str> = contents.lines().collect();
-    for (lineno, line) in lines.iter().enumerate() {
-        // If we hit an exemption for the entire file, bail.
-        if is_file_exempt(line) {
-            checks.drain(..);
-            return;
-        }
-
-        // Grab the noqa (logical) line number for the current (physical) line.
-        // If there are newlines at the end of the file, they won't be represented in
-        // `noqa_line_for`, so fallback to the current line.
-        let noqa_lineno = noqa_line_for.get(&(lineno + 1)).unwrap_or(&(lineno + 1)) - 1;
-
-        // Enforce unnecessary coding comments (UP009).
-        if enforce_unnecessary_coding_comment {
-            if lineno < 2 {
-                // PEP3120 makes utf-8 the default encoding.
-                if CODING_COMMENT_REGEX.is_match(line) {
-                    let mut check = Check::new(
-                        CheckKind::PEP3120UnnecessaryCodingComment,
-                        Range {
-                            location: Location::new(lineno + 1, 0),
-                            end_location: Location::new(lineno + 2, 0),
-                        },
-                    );
-                    if autofix && settings.fixable.contains(check.kind.code()) {
-                        check.amend(Fix::deletion(
-                            Location::new(lineno + 1, 0),
-                            Location::new(lineno + 2, 0),
-                        ));
-                    }
-                    add_if!(check, noqa_lineno, lines[noqa_lineno]);
-                }
-            }
-        }
-
-        if enforce_noqa {
-            noqa_directives
-                .entry(noqa_lineno)
-                .or_insert_with(|| (noqa::extract_noqa_directive(lines[noqa_lineno]), vec![]));
-        }
-
-        // Remove any ignored checks.
-        while let Some((index, check)) =
-            checks_iter.next_if(|(_index, check)| check.location.row() == lineno + 1)
-        {
-            let noqa = noqa_directives
-                .entry(noqa_lineno)
-                .or_insert_with(|| (noqa::extract_noqa_directive(lines[noqa_lineno]), vec![]));
-
-            match noqa {
-                (Directive::All(..), matches) => {
-                    matches.push(check.kind.code().as_ref());
-                    ignored.push(index);
-                }
-                (Directive::Codes(.., codes), matches) => {
-                    if noqa::includes(check.kind.code(), codes) {
-                        matches.push(check.kind.code().as_ref());
-                        ignored.push(index);
-                    }
-                }
-                (Directive::None, ..) => {}
-            }
-        }
-
-        // Enforce line length violations (E501).
-        if enforce_line_too_long {
-            let line_length = line.chars().count();
-            if should_enforce_line_length(line, line_length, settings.line_length) {
-                let check = Check::new(
-                    CheckKind::LineTooLong(line_length, settings.line_length),
-                    Range {
-                        location: Location::new(lineno + 1, 0),
-                        end_location: Location::new(lineno + 1, line_length),
-                    },
-                );
-                add_if!(check, noqa_lineno, lines[noqa_lineno]);
-            }
-        }
-    }
-
-    // Enforce newlines at end of files (W292).
-    if settings.enabled.contains(&CheckCode::W292) && !contents.ends_with('\n') {
-        // Note: if `lines.last()` is `None`, then `contents` is empty (and so we don't
-        // want to raise W292 anyway).
-        if let Some(line) = lines.last() {
-            let check = Check::new(
-                CheckKind::NoNewLineAtEndOfFile,
-                Range {
-                    location: Location::new(lines.len(), line.len() + 1),
-                    end_location: Location::new(lines.len(), line.len() + 1),
-                },
-            );
-
-            let lineno = lines.len() - 1;
-            let noqa_lineno = noqa_line_for.get(&(lineno + 1)).unwrap_or(&(lineno + 1)) - 1;
-            add_if!(check, noqa_lineno, lines[noqa_lineno]);
-        }
-    }
-
-    // Enforce that the noqa directive was actually used (RUF100).
-    if enforce_noqa {
-        for (row, (directive, matches)) in noqa_directives {
-            match directive {
-                Directive::All(spaces, start, end) => {
-                    if matches.is_empty() {
-                        let mut check = Check::new(
-                            CheckKind::UnusedNOQA(None),
-                            Range {
-                                location: Location::new(row + 1, start),
-                                end_location: Location::new(row + 1, end),
-                            },
-                        );
-                        if autofix && settings.fixable.contains(check.kind.code()) {
-                            check.amend(Fix::deletion(
-                                Location::new(row + 1, start - spaces),
-                                Location::new(row + 1, lines[row].chars().count()),
-                            ));
-                        }
-                        line_checks.push(check);
-                    }
-                }
-                Directive::Codes(spaces, start, end, codes) => {
-                    let mut invalid_codes = vec![];
-                    let mut valid_codes = vec![];
-                    for code in codes {
-                        let code = CODE_REDIRECTS.get(code).map_or(code, AsRef::as_ref);
-                        if matches.contains(&code) || settings.external.contains(code) {
-                            valid_codes.push(code.to_string());
-                        } else {
-                            invalid_codes.push(code.to_string());
-                        }
-                    }
-
-                    if !invalid_codes.is_empty() {
-                        let mut check = Check::new(
-                            CheckKind::UnusedNOQA(Some(invalid_codes)),
-                            Range {
-                                location: Location::new(row + 1, start),
-                                end_location: Location::new(row + 1, end),
-                            },
-                        );
-                        if autofix && settings.fixable.contains(check.kind.code()) {
-                            if valid_codes.is_empty() {
-                                check.amend(Fix::deletion(
-                                    Location::new(row + 1, start - spaces),
-                                    Location::new(row + 1, lines[row].chars().count()),
-                                ));
-                            } else {
-                                check.amend(Fix::replacement(
-                                    format!("# noqa: {}", valid_codes.join(", ")),
-                                    Location::new(row + 1, start),
-                                    Location::new(row + 1, lines[row].chars().count()),
-                                ));
-                            }
-                        }
-                        line_checks.push(check);
-                    }
-                }
-                Directive::None => {}
-            }
-        }
-    }
-
-    if !ignore_noqa {
-        ignored.sort_unstable();
-        for index in ignored.iter().rev() {
-            checks.swap_remove(*index);
-        }
-    }
-    checks.extend(line_checks);
-}
-
-#[cfg(test)]
-mod tests {
-    use nohash_hasher::IntMap;
-
-    use super::check_lines;
-    use crate::checks::{Check, CheckCode};
-    use crate::settings::Settings;
-
-    #[test]
-    fn e501_non_ascii_char() {
-        let line = "'\u{4e9c}' * 2"; // 7 in UTF-32, 9 in UTF-8.
-        let check_with_max_line_length = |line_length: usize| {
-            let mut checks: Vec<Check> = vec![];
-            check_lines(
-                &mut checks,
-                line,
-                &IntMap::default(),
-                &Settings {
-                    line_length,
-                    ..Settings::for_rule(CheckCode::E501)
-                },
-                true,
-                false,
-            );
-            checks
-        };
-        assert!(!check_with_max_line_length(6).is_empty());
-        assert!(check_with_max_line_length(7).is_empty());
-    }
-}

src/checkers/ast.rs

@@ -6,7 +6,7 @@ use itertools::Itertools;
 use log::error;
 use nohash_hasher::IntMap;
 use rustc_hash::{FxHashMap, FxHashSet};
-use rustpython_ast::Location;
+use rustpython_ast::{Located, Location};
 use rustpython_parser::ast::{
     Arg, Arguments, Constant, Excepthandler, ExcepthandlerKind, Expr, ExprContext, ExprKind,
     KeywordData, Operator, Stmt, StmtKind, Suite,
@@ -25,21 +25,22 @@ use crate::ast::visitor::{walk_excepthandler, Visitor};
 use crate::ast::{branch_detection, cast, helpers, operations, visitor};
 use crate::checks::{Check, CheckCode, CheckKind, DeferralKeyword};
 use crate::docstrings::definition::{Definition, DefinitionKind, Docstring, Documentable};
+use crate::noqa::Directive;
 use crate::python::builtins::{BUILTINS, MAGIC_GLOBALS};
 use crate::python::future::ALL_FEATURE_NAMES;
 use crate::python::typing;
 use crate::python::typing::SubscriptKind;
 use crate::settings::types::PythonVersion;
-use crate::settings::Settings;
+use crate::settings::{flags, Settings};
 use crate::source_code_locator::SourceCodeLocator;
 use crate::vendored::cformat::{CFormatError, CFormatErrorType};
 use crate::visibility::{module_visibility, transition_scope, Modifier, Visibility, VisibleScope};
 use crate::{
     docstrings, flake8_2020, flake8_annotations, flake8_bandit, flake8_blind_except,
     flake8_boolean_trap, flake8_bugbear, flake8_builtins, flake8_comprehensions, flake8_debugger,
-    flake8_import_conventions, flake8_print, flake8_return, flake8_simplify, flake8_tidy_imports,
-    flake8_unused_arguments, mccabe, pep8_naming, pycodestyle, pydocstyle, pyflakes, pygrep_hooks,
-    pylint, pyupgrade, visibility,
+    flake8_errmsg, flake8_import_conventions, flake8_print, flake8_return, flake8_simplify,
+    flake8_tidy_imports, flake8_unused_arguments, mccabe, noqa, pandas_vet, pep8_naming,
+    pycodestyle, pydocstyle, pyflakes, pygrep_hooks, pylint, pyupgrade, visibility,
 };
 
 const GLOBAL_SCOPE_INDEX: usize = 0;
@@ -50,8 +51,10 @@ type DeferralContext<'a> = (Vec<usize>, Vec<RefEquality<'a, Stmt>>);
 pub struct Checker<'a> {
     // Input data.
     path: &'a Path,
-    autofix: bool,
+    autofix: flags::Autofix,
+    noqa: flags::Noqa,
     pub(crate) settings: &'a Settings,
+    pub(crate) noqa_line_for: &'a IntMap<usize, usize>,
     pub(crate) locator: &'a SourceCodeLocator<'a>,
     // Computed checks.
     checks: Vec<Check>,
@@ -98,13 +101,17 @@ pub struct Checker<'a> {
 impl<'a> Checker<'a> {
     pub fn new(
         settings: &'a Settings,
-        autofix: bool,
+        noqa_line_for: &'a IntMap<usize, usize>,
+        autofix: flags::Autofix,
+        noqa: flags::Noqa,
         path: &'a Path,
         locator: &'a SourceCodeLocator,
     ) -> Checker<'a> {
         Checker {
             settings,
+            noqa_line_for,
             autofix,
+            noqa,
             path,
             locator,
             checks: vec![],
@@ -175,7 +182,9 @@ impl<'a> Checker<'a> {
     pub fn patch(&self, code: &CheckCode) -> bool {
         // TODO(charlie): We can't fix errors in f-strings until RustPython adds
         // location data.
-        self.autofix && self.in_f_string.is_none() && self.settings.fixable.contains(code)
+        matches!(self.autofix, flags::Autofix::Enabled)
+            && self.in_f_string.is_none()
+            && self.settings.fixable.contains(code)
     }
 
     /// Return `true` if the `Expr` is a reference to `typing.${target}`.
@@ -199,6 +208,30 @@ impl<'a> Checker<'a> {
                 matches!(self.bindings[*index].kind, BindingKind::Builtin)
             })
     }
+
+    /// Return `true` if a `CheckCode` is disabled by a `noqa` directive.
+    pub fn is_ignored(&self, code: &CheckCode, lineno: usize) -> bool {
+        // TODO(charlie): `noqa` directives are mostly enforced in `check_lines.rs`.
+        // However, in rare cases, we need to check them here. For example, when
+        // removing unused imports, we create a single fix that's applied to all
+        // unused members on a single import. We need to pre-emptively omit any
+        // members from the fix that will eventually be excluded by a `noqa`.
+        // Unfortunately, we _do_ want to register a `Check` for each eventually-ignored
+        // import, so that our `noqa` counts are accurate.
+        if matches!(self.noqa, flags::Noqa::Disabled) {
+            return false;
+        }
+        let noqa_lineno = self.noqa_line_for.get(&lineno).unwrap_or(&lineno);
+        let line = self.locator.slice_source_code_range(&Range {
+            location: Location::new(*noqa_lineno, 0),
+            end_location: Location::new(noqa_lineno + 1, 0),
+        });
+        match noqa::extract_noqa_directive(&line) {
+            Directive::None => false,
+            Directive::All(..) => true,
+            Directive::Codes(.., codes) => noqa::includes(code, &codes),
+        }
+    }
 }
 
 impl<'a, 'b> Visitor<'b> for Checker<'a>
@@ -223,10 +256,10 @@ where
             StmtKind::Import { .. } => {
                 self.futures_allowed = false;
             }
-            node => {
+            _ => {
                 self.futures_allowed = false;
                 if !self.seen_import_boundary
-                    && !helpers::is_assignment_to_a_dunder(node)
+                    && !helpers::is_assignment_to_a_dunder(stmt)
                     && !operations::in_nested_block(
                         &mut self.parents.iter().rev().map(|node| node.0),
                     )
@@ -257,12 +290,11 @@ where
                 }
 
                 if self.settings.enabled.contains(&CheckCode::E741) {
-                    let location = Range::from_located(stmt);
                     self.add_checks(
                         names
                             .iter()
                             .filter_map(|name| {
-                                pycodestyle::checks::ambiguous_variable_name(name, location)
+                                pycodestyle::checks::ambiguous_variable_name(name, stmt)
                             })
                             .into_iter(),
                     );
@@ -309,12 +341,11 @@ where
                 }
 
                 if self.settings.enabled.contains(&CheckCode::E741) {
-                    let location = Range::from_located(stmt);
                     self.add_checks(
                         names
                             .iter()
                             .filter_map(|name| {
-                                pycodestyle::checks::ambiguous_variable_name(name, location)
+                                pycodestyle::checks::ambiguous_variable_name(name, stmt)
                             })
                             .into_iter(),
                     );
@@ -369,7 +400,8 @@ where
                     if let Some(check) = pep8_naming::checks::invalid_function_name(
                         stmt,
                         name,
-                        &self.settings.pep8_naming,
+                        &self.settings.pep8_naming.ignore_names,
+                        self.locator,
                     ) {
                         self.add_check(check);
                     }
@@ -406,9 +438,12 @@ where
                 }
 
                 if self.settings.enabled.contains(&CheckCode::N807) {
-                    if let Some(check) =
-                        pep8_naming::checks::dunder_function_name(self.current_scope(), stmt, name)
-                    {
+                    if let Some(check) = pep8_naming::checks::dunder_function_name(
+                        self.current_scope(),
+                        stmt,
+                        name,
+                        self.locator,
+                    ) {
                         self.add_check(check);
                     }
                 }
@@ -445,6 +480,7 @@ where
                         name,
                         body,
                         self.settings.mccabe.max_complexity,
+                        self.locator,
                     ) {
                         self.add_check(check);
                     }
@@ -460,7 +496,7 @@ where
                     pylint::plugins::property_with_parameters(self, stmt, decorator_list, args);
                 }
 
-                self.check_builtin_shadowing(name, Range::from_located(stmt), true);
+                self.check_builtin_shadowing(name, stmt, true);
 
                 // Visit the decorators and arguments, but avoid the body, which will be
                 // deferred.
@@ -548,7 +584,9 @@ where
                 }
 
                 if self.settings.enabled.contains(&CheckCode::N801) {
-                    if let Some(check) = pep8_naming::checks::invalid_class_name(stmt, name) {
+                    if let Some(check) =
+                        pep8_naming::checks::invalid_class_name(stmt, name, self.locator)
+                    {
                         self.add_check(check);
                     }
                 }
@@ -573,7 +611,7 @@ where
                     );
                 }
 
-                self.check_builtin_shadowing(name, Range::from_located(stmt), false);
+                self.check_builtin_shadowing(name, stmt, false);
 
                 for expr in bases {
                     self.visit_expr(expr);
@@ -615,7 +653,7 @@ where
                         );
                     } else {
                         if let Some(asname) = &alias.node.asname {
-                            self.check_builtin_shadowing(asname, Range::from_located(stmt), false);
+                            self.check_builtin_shadowing(asname, stmt, false);
                         }
 
                         // Given `import foo`, `name` and `full_name` would both be `foo`.
@@ -683,7 +721,10 @@ where
                         if self.settings.enabled.contains(&CheckCode::N811) {
                             if let Some(check) =
                                 pep8_naming::checks::constant_imported_as_non_constant(
-                                    stmt, name, asname,
+                                    stmt,
+                                    name,
+                                    asname,
+                                    self.locator,
                                 )
                             {
                                 self.add_check(check);
@@ -693,7 +734,10 @@ where
                         if self.settings.enabled.contains(&CheckCode::N812) {
                             if let Some(check) =
                                 pep8_naming::checks::lowercase_imported_as_non_lowercase(
-                                    stmt, name, asname,
+                                    stmt,
+                                    name,
+                                    asname,
+                                    self.locator,
                                 )
                             {
                                 self.add_check(check);
@@ -703,7 +747,10 @@ where
                         if self.settings.enabled.contains(&CheckCode::N813) {
                             if let Some(check) =
                                 pep8_naming::checks::camelcase_imported_as_lowercase(
-                                    stmt, name, asname,
+                                    stmt,
+                                    name,
+                                    asname,
+                                    self.locator,
                                 )
                             {
                                 self.add_check(check);
@@ -712,7 +759,10 @@ where
 
                         if self.settings.enabled.contains(&CheckCode::N814) {
                             if let Some(check) = pep8_naming::checks::camelcase_imported_as_constant(
-                                stmt, name, asname,
+                                stmt,
+                                name,
+                                asname,
+                                self.locator,
                             ) {
                                 self.add_check(check);
                             }
@@ -720,7 +770,10 @@ where
 
                         if self.settings.enabled.contains(&CheckCode::N817) {
                             if let Some(check) = pep8_naming::checks::camelcase_imported_as_acronym(
-                                stmt, name, asname,
+                                stmt,
+                                name,
+                                asname,
+                                self.locator,
                             ) {
                                 self.add_check(check);
                             }
@@ -858,7 +911,7 @@ where
                         scope.import_starred = true;
                     } else {
                         if let Some(asname) = &alias.node.asname {
-                            self.check_builtin_shadowing(asname, Range::from_located(stmt), false);
+                            self.check_builtin_shadowing(asname, stmt, false);
                         }
 
                         // Given `from foo import bar`, `name` would be "bar" and `full_name` would
@@ -927,6 +980,7 @@ where
                                     stmt,
                                     &alias.node.name,
                                     asname,
+                                    self.locator,
                                 )
                             {
                                 self.add_check(check);
@@ -939,6 +993,7 @@ where
                                     stmt,
                                     &alias.node.name,
                                     asname,
+                                    self.locator,
                                 )
                             {
                                 self.add_check(check);
@@ -951,6 +1006,7 @@ where
                                     stmt,
                                     &alias.node.name,
                                     asname,
+                                    self.locator,
                                 )
                             {
                                 self.add_check(check);
@@ -962,6 +1018,7 @@ where
                                 stmt,
                                 &alias.node.name,
                                 asname,
+                                self.locator,
                             ) {
                                 self.add_check(check);
                             }
@@ -972,6 +1029,7 @@ where
                                 stmt,
                                 &alias.node.name,
                                 asname,
+                                self.locator,
                             ) {
                                 self.add_check(check);
                             }
@@ -995,6 +1053,20 @@ where
                         flake8_bugbear::plugins::cannot_raise_literal(self, exc);
                     }
                 }
+                if self.settings.enabled.contains(&CheckCode::EM101)
+                    | self.settings.enabled.contains(&CheckCode::EM102)
+                    | self.settings.enabled.contains(&CheckCode::EM103)
+                {
+                    if let Some(exc) = exc {
+                        self.add_checks(
+                            flake8_errmsg::checks::check_string_in_exception(
+                                exc,
+                                self.settings.flake8_errmsg.max_string_length,
+                            )
+                            .into_iter(),
+                        );
+                    }
+                }
             }
             StmtKind::AugAssign { target, .. } => {
                 self.handle_node_load(target);
@@ -1107,6 +1179,11 @@ where
                         self, stmt, targets, value,
                     );
                 }
+                if self.settings.enabled.contains(&CheckCode::PDV901) {
+                    if let Some(check) = pandas_vet::checks::assignment_to_df(targets) {
+                        self.add_check(check);
+                    }
+                }
             }
             StmtKind::AnnAssign { target, value, .. } => {
                 if self.settings.enabled.contains(&CheckCode::E731) {
@@ -1422,15 +1499,14 @@ where
                     }
                     ExprContext::Store => {
                         if self.settings.enabled.contains(&CheckCode::E741) {
-                            if let Some(check) = pycodestyle::checks::ambiguous_variable_name(
-                                id,
-                                Range::from_located(expr),
-                            ) {
+                            if let Some(check) =
+                                pycodestyle::checks::ambiguous_variable_name(id, expr)
+                            {
                                 self.add_check(check);
                             }
                         }
 
-                        self.check_builtin_shadowing(id, Range::from_located(expr), true);
+                        self.check_builtin_shadowing(id, expr, true);
 
                         self.handle_node_store(id, expr);
                     }
@@ -1458,9 +1534,26 @@ where
                     pyupgrade::plugins::use_pep585_annotation(self, expr, attr);
                 }
 
+                if self.settings.enabled.contains(&CheckCode::UP016) {
+                    pyupgrade::plugins::remove_six_compat(self, expr);
+                }
+
                 if self.settings.enabled.contains(&CheckCode::YTT202) {
                     flake8_2020::plugins::name_or_attribute(self, expr);
                 }
+
+                for (code, name) in vec![
+                    (CheckCode::PDV007, "ix"),
+                    (CheckCode::PDV008, "at"),
+                    (CheckCode::PDV009, "iat"),
+                    (CheckCode::PDV011, "values"),
+                ] {
+                    if self.settings.enabled.contains(&code) {
+                        if attr == name {
+                            self.add_check(Check::new(code.kind(), Range::from_located(expr)));
+                        };
+                    }
+                }
             }
             ExprKind::Call {
                 func,
@@ -1533,6 +1626,9 @@ where
                 if self.settings.enabled.contains(&CheckCode::UP012) {
                     pyupgrade::plugins::unnecessary_encode_utf8(self, expr, func, args, keywords);
                 }
+                if self.settings.enabled.contains(&CheckCode::UP016) {
+                    pyupgrade::plugins::remove_six_compat(self, expr);
+                }
 
                 // flake8-super
                 if self.settings.enabled.contains(&CheckCode::UP008) {
@@ -1557,14 +1653,7 @@ where
                     flake8_bugbear::plugins::getattr_with_constant(self, expr, func, args);
                 }
                 if self.settings.enabled.contains(&CheckCode::B010) {
-                    if !self
-                        .scope_stack
-                        .iter()
-                        .rev()
-                        .any(|index| matches!(self.scopes[*index].kind, ScopeKind::Lambda(..)))
-                    {
-                        flake8_bugbear::plugins::setattr_with_constant(self, expr, func, args);
-                    }
+                    flake8_bugbear::plugins::setattr_with_constant(self, expr, func, args);
                 }
                 if self.settings.enabled.contains(&CheckCode::B022) {
                     flake8_bugbear::plugins::useless_contextlib_suppress(self, expr, args);
@@ -1838,6 +1927,34 @@ where
                     }
                 }
 
+                // pandas-vet
+                if self.settings.enabled.contains(&CheckCode::PDV002) {
+                    self.add_checks(pandas_vet::checks::inplace_argument(keywords).into_iter());
+                }
+
+                for (code, name) in vec![
+                    (CheckCode::PDV003, "isnull"),
+                    (CheckCode::PDV004, "notnull"),
+                    (CheckCode::PDV010, "pivot"),
+                    (CheckCode::PDV010, "unstack"),
+                    (CheckCode::PDV012, "read_table"),
+                    (CheckCode::PDV013, "stack"),
+                ] {
+                    if self.settings.enabled.contains(&code) {
+                        if let ExprKind::Attribute { attr, .. } = &func.node {
+                            if attr == name {
+                                self.add_check(Check::new(code.kind(), Range::from_located(func)));
+                            };
+                        }
+                    }
+                }
+
+                if self.settings.enabled.contains(&CheckCode::PDV015) {
+                    if let Some(check) = pandas_vet::checks::use_of_pd_merge(func) {
+                        self.add_check(check);
+                    };
+                }
+
                 // pygrep-hooks
                 if self.settings.enabled.contains(&CheckCode::PGH001) {
                     pygrep_hooks::checks::no_eval(self, func);
@@ -2420,19 +2537,14 @@ where
                 match name {
                     Some(name) => {
                         if self.settings.enabled.contains(&CheckCode::E741) {
-                            if let Some(check) = pycodestyle::checks::ambiguous_variable_name(
-                                name,
-                                Range::from_located(excepthandler),
-                            ) {
+                            if let Some(check) =
+                                pycodestyle::checks::ambiguous_variable_name(name, excepthandler)
+                            {
                                 self.add_check(check);
                             }
                         }
 
-                        self.check_builtin_shadowing(
-                            name,
-                            Range::from_located(excepthandler),
-                            false,
-                        );
+                        self.check_builtin_shadowing(name, excepthandler, false);
 
                         if self.current_scope().values.contains_key(&name.as_str()) {
                             self.handle_node_store(
@@ -2545,23 +2657,18 @@ where
         );
 
         if self.settings.enabled.contains(&CheckCode::E741) {
-            if let Some(check) = pycodestyle::checks::ambiguous_variable_name(
-                &arg.node.arg,
-                Range::from_located(arg),
-            ) {
+            if let Some(check) = pycodestyle::checks::ambiguous_variable_name(&arg.node.arg, arg) {
                 self.add_check(check);
             }
         }
 
         if self.settings.enabled.contains(&CheckCode::N803) {
-            if let Some(check) =
-                pep8_naming::checks::invalid_argument_name(&arg.node.arg, Range::from_located(arg))
-            {
+            if let Some(check) = pep8_naming::checks::invalid_argument_name(&arg.node.arg, arg) {
                 self.add_check(check);
             }
         }
 
-        self.check_builtin_arg_shadowing(&arg.node.arg, Range::from_located(arg));
+        self.check_builtin_arg_shadowing(&arg.node.arg, arg);
     }
 }
 
@@ -3322,6 +3429,8 @@ impl<'a> Checker<'a> {
                     (&'a RefEquality<'b, Stmt>, Option<&'a RefEquality<'b, Stmt>>);
 
                 let mut unused: FxHashMap<BindingContext, Vec<UnusedImport>> = FxHashMap::default();
+                let mut ignored: FxHashMap<BindingContext, Vec<UnusedImport>> =
+                    FxHashMap::default();
 
                 for (name, index) in scope
                     .values
@@ -3346,12 +3455,21 @@ impl<'a> Checker<'a> {
 
                     let defined_by = binding.source.as_ref().unwrap();
                     let defined_in = self.child_to_parent.get(defined_by);
-                    unused
-                        .entry((defined_by, defined_in))
-                        .or_default()
-                        .push((full_name, &binding.range));
+                    if self.is_ignored(&CheckCode::F401, binding.range.location.row()) {
+                        ignored
+                            .entry((defined_by, defined_in))
+                            .or_default()
+                            .push((full_name, &binding.range));
+                    } else {
+                        unused
+                            .entry((defined_by, defined_in))
+                            .or_default()
+                            .push((full_name, &binding.range));
+                    }
                 }
 
+                let ignore_init =
+                    self.settings.ignore_init_module_imports && self.path.ends_with("__init__.py");
                 for ((defined_by, defined_in), unused_imports) in unused
                     .into_iter()
                     .sorted_by_key(|((defined_by, _), _)| defined_by.0.location)
@@ -3359,17 +3477,15 @@ impl<'a> Checker<'a> {
                     let child = defined_by.0;
                     let parent = defined_in.map(|defined_in| defined_in.0);
 
-                    let ignore_init = self.settings.ignore_init_module_imports
-                        && self.path.ends_with("__init__.py");
                     let fix = if !ignore_init && self.patch(&CheckCode::F401) {
                         let deleted: Vec<&Stmt> =
                             self.deletions.iter().map(|node| node.0).collect();
                         match pyflakes::fixes::remove_unused_imports(
-                            self.locator,
                             &unused_imports,
                             child,
                             parent,
                             &deleted,
+                            self.locator,
                         ) {
                             Ok(fix) => {
                                 if fix.content.is_empty() || fix.content == "pass" {
@@ -3397,6 +3513,17 @@ impl<'a> Checker<'a> {
                         checks.push(check);
                     }
                 }
+                for (_, unused_imports) in ignored
+                    .into_iter()
+                    .sorted_by_key(|((defined_by, _), _)| defined_by.0.location)
+                {
+                    for (full_name, range) in unused_imports {
+                        checks.push(Check::new(
+                            CheckKind::UnusedImport(full_name.clone(), ignore_init),
+                            *range,
+                        ));
+                    }
+                }
             }
         }
         self.add_checks(checks.into_iter());
@@ -3591,12 +3718,12 @@ impl<'a> Checker<'a> {
         }
     }
 
-    fn check_builtin_shadowing(&mut self, name: &str, location: Range, is_attribute: bool) {
+    fn check_builtin_shadowing<T>(&mut self, name: &str, located: &Located<T>, is_attribute: bool) {
         if is_attribute && matches!(self.current_scope().kind, ScopeKind::Class(_)) {
             if self.settings.enabled.contains(&CheckCode::A003) {
                 if let Some(check) = flake8_builtins::checks::builtin_shadowing(
                     name,
-                    location,
+                    located,
                     flake8_builtins::types::ShadowingType::Attribute,
                 ) {
                     self.add_check(check);
@@ -3606,7 +3733,7 @@ impl<'a> Checker<'a> {
             if self.settings.enabled.contains(&CheckCode::A001) {
                 if let Some(check) = flake8_builtins::checks::builtin_shadowing(
                     name,
-                    location,
+                    located,
                     flake8_builtins::types::ShadowingType::Variable,
                 ) {
                     self.add_check(check);
@@ -3615,11 +3742,11 @@ impl<'a> Checker<'a> {
         }
     }
 
-    fn check_builtin_arg_shadowing(&mut self, name: &str, location: Range) {
+    fn check_builtin_arg_shadowing(&mut self, name: &str, arg: &Arg) {
         if self.settings.enabled.contains(&CheckCode::A002) {
             if let Some(check) = flake8_builtins::checks::builtin_shadowing(
                 name,
-                location,
+                arg,
                 flake8_builtins::types::ShadowingType::Argument,
             ) {
                 self.add_check(check);
@@ -3631,11 +3758,13 @@ impl<'a> Checker<'a> {
 pub fn check_ast(
     python_ast: &Suite,
     locator: &SourceCodeLocator,
+    noqa_line_for: &IntMap<usize, usize>,
     settings: &Settings,
-    autofix: bool,
+    autofix: flags::Autofix,
+    noqa: flags::Noqa,
     path: &Path,
 ) -> Vec<Check> {
-    let mut checker = Checker::new(settings, autofix, path, locator);
+    let mut checker = Checker::new(settings, noqa_line_for, autofix, noqa, path, locator);
     checker.push_scope(Scope::new(ScopeKind::Module));
     checker.bind_builtins();
 

src/checkers/imports.rs

@@ -9,19 +9,22 @@ use crate::checks::Check;
 use crate::directives::IsortDirectives;
 use crate::isort;
 use crate::isort::track::ImportTracker;
-use crate::settings::Settings;
+use crate::settings::{flags, Settings};
 use crate::source_code_locator::SourceCodeLocator;
 
 fn check_import_blocks(
     tracker: ImportTracker,
     locator: &SourceCodeLocator,
     settings: &Settings,
-    autofix: bool,
+    autofix: flags::Autofix,
+    package: Option<&Path>,
 ) -> Vec<Check> {
     let mut checks = vec![];
     for block in tracker.into_iter() {
         if !block.imports.is_empty() {
-            if let Some(check) = isort::plugins::check_imports(&block, locator, settings, autofix) {
+            if let Some(check) =
+                isort::plugins::check_imports(&block, locator, settings, autofix, package)
+            {
                 checks.push(check);
             }
         }
@@ -34,12 +37,13 @@ pub fn check_imports(
     locator: &SourceCodeLocator,
     directives: &IsortDirectives,
     settings: &Settings,
-    autofix: bool,
+    autofix: flags::Autofix,
     path: &Path,
+    package: Option<&Path>,
 ) -> Vec<Check> {
     let mut tracker = ImportTracker::new(locator, directives, path);
     for stmt in python_ast {
         tracker.visit_stmt(stmt);
     }
-    check_import_blocks(tracker, locator, settings, autofix)
+    check_import_blocks(tracker, locator, settings, autofix, package)
 }

src/checkers/lines.rs

@@ -0,0 +1,71 @@
+//! Lint rules based on checking raw physical lines.
+
+use crate::checks::{Check, CheckCode};
+use crate::pycodestyle::checks::{line_too_long, no_newline_at_end_of_file};
+use crate::pyupgrade::checks::unnecessary_coding_comment;
+use crate::settings::{flags, Settings};
+
+pub fn check_lines(contents: &str, settings: &Settings, autofix: flags::Autofix) -> Vec<Check> {
+    let mut checks: Vec<Check> = vec![];
+
+    let enforce_unnecessary_coding_comment = settings.enabled.contains(&CheckCode::UP009);
+    let enforce_line_too_long = settings.enabled.contains(&CheckCode::E501);
+    let enforce_no_newline_at_end_of_file = settings.enabled.contains(&CheckCode::W292);
+
+    for (lineno, line) in contents.lines().enumerate() {
+        // Enforce unnecessary coding comments (UP009).
+        if enforce_unnecessary_coding_comment {
+            if lineno < 2 {
+                if let Some(check) = unnecessary_coding_comment(
+                    lineno,
+                    line,
+                    matches!(autofix, flags::Autofix::Enabled)
+                        && settings.fixable.contains(&CheckCode::UP009),
+                ) {
+                    checks.push(check);
+                }
+            }
+        }
+
+        // Enforce line length violations (E501).
+        if enforce_line_too_long {
+            if let Some(check) = line_too_long(lineno, line, settings.line_length) {
+                checks.push(check);
+            }
+        }
+    }
+
+    // Enforce newlines at end of files (W292).
+    if enforce_no_newline_at_end_of_file {
+        if let Some(check) = no_newline_at_end_of_file(contents) {
+            checks.push(check);
+        }
+    }
+
+    checks
+}
+
+#[cfg(test)]
+mod tests {
+
+    use super::check_lines;
+    use crate::checks::CheckCode;
+    use crate::settings::{flags, Settings};
+
+    #[test]
+    fn e501_non_ascii_char() {
+        let line = "'\u{4e9c}' * 2"; // 7 in UTF-32, 9 in UTF-8.
+        let check_with_max_line_length = |line_length: usize| {
+            check_lines(
+                line,
+                &Settings {
+                    line_length,
+                    ..Settings::for_rule(CheckCode::E501)
+                },
+                flags::Autofix::Enabled,
+            )
+        };
+        assert!(!check_with_max_line_length(6).is_empty());
+        assert!(check_with_max_line_length(7).is_empty());
+    }
+}

src/checkers/mod.rs

@@ -0,0 +1,5 @@
+pub mod ast;
+pub mod imports;
+pub mod lines;
+pub mod noqa;
+pub mod tokens;

src/checkers/noqa.rs

@@ -0,0 +1,148 @@
+//! `NoQA` enforcement and validation.
+
+use nohash_hasher::IntMap;
+use rustpython_parser::ast::Location;
+
+use crate::ast::types::Range;
+use crate::autofix::Fix;
+use crate::checks::{Check, CheckCode, CheckKind, CODE_REDIRECTS};
+use crate::noqa;
+use crate::noqa::{is_file_exempt, Directive};
+use crate::settings::{flags, Settings};
+
+pub fn check_noqa(
+    checks: &mut Vec<Check>,
+    contents: &str,
+    commented_lines: &[usize],
+    noqa_line_for: &IntMap<usize, usize>,
+    settings: &Settings,
+    autofix: flags::Autofix,
+) {
+    let mut noqa_directives: IntMap<usize, (Directive, Vec<&str>)> = IntMap::default();
+    let mut ignored = vec![];
+
+    let enforce_noqa = settings.enabled.contains(&CheckCode::RUF100);
+
+    checks.sort_by_key(|check| check.location);
+    let mut checks_iter = checks.iter().enumerate().peekable();
+    if let Some((_index, check)) = checks_iter.peek() {
+        assert!(check.location.row() >= 1);
+    }
+
+    let lines: Vec<&str> = contents.lines().collect();
+    for lineno in commented_lines {
+        // If we hit an exemption for the entire file, bail.
+        if is_file_exempt(lines[lineno - 1]) {
+            checks.drain(..);
+            return;
+        }
+
+        if enforce_noqa {
+            noqa_directives
+                .entry(lineno - 1)
+                .or_insert_with(|| (noqa::extract_noqa_directive(lines[lineno - 1]), vec![]));
+        }
+
+        // Remove any ignored checks.
+        while let Some((index, check)) =
+            checks_iter.next_if(|(_index, check)| check.location.row() <= *lineno)
+        {
+            // Grab the noqa (logical) line number for the current (physical) line.
+            // If there are newlines at the end of the file, they won't be represented in
+            // `noqa_line_for`, so fallback to the current line.
+            let check_lineno = check.location.row();
+            let noqa_lineno = noqa_line_for.get(&check_lineno).unwrap_or(&check_lineno);
+            if noqa_lineno == lineno {
+                let noqa = noqa_directives.entry(noqa_lineno - 1).or_insert_with(|| {
+                    (noqa::extract_noqa_directive(lines[noqa_lineno - 1]), vec![])
+                });
+                match noqa {
+                    (Directive::All(..), matches) => {
+                        matches.push(check.kind.code().as_ref());
+                        ignored.push(index);
+                    }
+                    (Directive::Codes(.., codes), matches) => {
+                        if noqa::includes(check.kind.code(), codes) {
+                            matches.push(check.kind.code().as_ref());
+                            ignored.push(index);
+                        }
+                    }
+                    (Directive::None, ..) => {}
+                }
+            }
+        }
+    }
+
+    // Enforce that the noqa directive was actually used (RUF100).
+    if enforce_noqa {
+        for (row, (directive, matches)) in noqa_directives {
+            match directive {
+                Directive::All(spaces, start, end) => {
+                    if matches.is_empty() {
+                        let mut check = Check::new(
+                            CheckKind::UnusedNOQA(None),
+                            Range {
+                                location: Location::new(row + 1, start),
+                                end_location: Location::new(row + 1, end),
+                            },
+                        );
+                        if matches!(autofix, flags::Autofix::Enabled)
+                            && settings.fixable.contains(check.kind.code())
+                        {
+                            check.amend(Fix::deletion(
+                                Location::new(row + 1, start - spaces),
+                                Location::new(row + 1, lines[row].chars().count()),
+                            ));
+                        }
+                        checks.push(check);
+                    }
+                }
+                Directive::Codes(spaces, start, end, codes) => {
+                    let mut invalid_codes = vec![];
+                    let mut valid_codes = vec![];
+                    for code in codes {
+                        let code = CODE_REDIRECTS.get(code).map_or(code, AsRef::as_ref);
+                        if matches.contains(&code) || settings.external.contains(code) {
+                            valid_codes.push(code.to_string());
+                        } else {
+                            invalid_codes.push(code.to_string());
+                        }
+                    }
+
+                    if !invalid_codes.is_empty() {
+                        let mut check = Check::new(
+                            CheckKind::UnusedNOQA(Some(invalid_codes)),
+                            Range {
+                                location: Location::new(row + 1, start),
+                                end_location: Location::new(row + 1, end),
+                            },
+                        );
+                        if matches!(autofix, flags::Autofix::Enabled)
+                            && settings.fixable.contains(check.kind.code())
+                        {
+                            if valid_codes.is_empty() {
+                                check.amend(Fix::deletion(
+                                    Location::new(row + 1, start - spaces),
+                                    Location::new(row + 1, lines[row].chars().count()),
+                                ));
+                            } else {
+                                check.amend(Fix::replacement(
+                                    format!("# noqa: {}", valid_codes.join(", ")),
+                                    Location::new(row + 1, start),
+                                    Location::new(row + 1, lines[row].chars().count()),
+                                ));
+                            }
+                        }
+                        checks.push(check);
+                    }
+                }
+                Directive::None => {}
+            }
+        }
+    }
+
+    ignored.sort_unstable();
+    for index in ignored.iter().rev() {
+        checks.swap_remove(*index);
+    }
+}

src/checkers/tokens.rs

@@ -5,6 +5,7 @@ use rustpython_parser::lexer::{LexResult, Tok};
 use crate::checks::{Check, CheckCode};
 use crate::lex::docstring_detection::StateMachine;
 use crate::ruff::checks::Context;
+use crate::settings::flags;
 use crate::source_code_locator::SourceCodeLocator;
 use crate::{eradicate, flake8_quotes, pycodestyle, ruff, Settings};
 
@@ -12,7 +13,7 @@ pub fn check_tokens(
     locator: &SourceCodeLocator,
     tokens: &[LexResult],
     settings: &Settings,
-    autofix: bool,
+    autofix: flags::Autofix,
 ) -> Vec<Check> {
     let mut checks: Vec<Check> = vec![];
 

src/checks.rs

@@ -223,6 +223,7 @@ pub enum CheckCode {
     UP013,
     UP014,
     UP015,
+    UP016,
     // pydocstyle
     D100,
     D101,
@@ -315,6 +316,23 @@ pub enum CheckCode {
     RUF100,
     // pygrep-hooks
     PGH001,
+    // pandas-vet
+    PDV002,
+    PDV003,
+    PDV004,
+    PDV007,
+    PDV008,
+    PDV009,
+    PDV010,
+    PDV011,
+    PDV012,
+    PDV013,
+    PDV015,
+    PDV901,
+    // flake8-errmsg
+    EM101,
+    EM102,
+    EM103,
 }
 
 #[derive(EnumIter, Debug, PartialEq, Eq)]
@@ -335,6 +353,7 @@ pub enum CheckCategory {
     Flake8Builtins,
     Flake8Comprehensions,
     Flake8Debugger,
+    Flake8ErrMsg,
     Flake8ImportConventions,
     Flake8Print,
     Flake8Quotes,
@@ -343,6 +362,7 @@ pub enum CheckCategory {
     Flake8TidyImports,
     Flake8UnusedArguments,
     Eradicate,
+    PandasVet,
     PygrepHooks,
     Pylint,
     Ruff,
@@ -375,6 +395,7 @@ impl CheckCategory {
             CheckCategory::Flake8Builtins => "flake8-builtins",
             CheckCategory::Flake8Comprehensions => "flake8-comprehensions",
             CheckCategory::Flake8Debugger => "flake8-debugger",
+            CheckCategory::Flake8ErrMsg => "flake8-errmsg",
             CheckCategory::Flake8ImportConventions => "flake8-import-conventions",
             CheckCategory::Flake8Print => "flake8-print",
             CheckCategory::Flake8Quotes => "flake8-quotes",
@@ -384,6 +405,7 @@ impl CheckCategory {
             CheckCategory::Flake8UnusedArguments => "flake8-unused-arguments",
             CheckCategory::Isort => "isort",
             CheckCategory::McCabe => "mccabe",
+            CheckCategory::PandasVet => "pandas-vet",
             CheckCategory::PEP8Naming => "pep8-naming",
             CheckCategory::Pycodestyle => "pycodestyle",
             CheckCategory::Pydocstyle => "pydocstyle",
@@ -407,6 +429,7 @@ impl CheckCategory {
             CheckCategory::Flake8Builtins => vec![CheckCodePrefix::A],
             CheckCategory::Flake8Comprehensions => vec![CheckCodePrefix::C4],
             CheckCategory::Flake8Debugger => vec![CheckCodePrefix::T10],
+            CheckCategory::Flake8ErrMsg => vec![CheckCodePrefix::EM],
             CheckCategory::Flake8Print => vec![CheckCodePrefix::T20],
             CheckCategory::Flake8Quotes => vec![CheckCodePrefix::Q],
             CheckCategory::Flake8Return => vec![CheckCodePrefix::RET],
@@ -415,6 +438,7 @@ impl CheckCategory {
             CheckCategory::Flake8UnusedArguments => vec![CheckCodePrefix::ARG],
             CheckCategory::Isort => vec![CheckCodePrefix::I],
             CheckCategory::McCabe => vec![CheckCodePrefix::C90],
+            CheckCategory::PandasVet => vec![CheckCodePrefix::PDV],
             CheckCategory::PEP8Naming => vec![CheckCodePrefix::N],
             CheckCategory::Pycodestyle => vec![CheckCodePrefix::E, CheckCodePrefix::W],
             CheckCategory::Pydocstyle => vec![CheckCodePrefix::D],
@@ -473,6 +497,10 @@ impl CheckCategory {
                 "https://pypi.org/project/flake8-debugger/4.1.2/",
                 &Platform::PyPI,
             )),
+            CheckCategory::Flake8ErrMsg => Some((
+                "https://pypi.org/project/flake8-errmsg/0.4.0/",
+                &Platform::PyPI,
+            )),
             CheckCategory::Flake8ImportConventions => None,
             CheckCategory::Flake8Print => Some((
                 "https://pypi.org/project/flake8-print/5.0.0/",
@@ -504,6 +532,10 @@ impl CheckCategory {
             CheckCategory::McCabe => {
                 Some(("https://pypi.org/project/mccabe/0.7.0/", &Platform::PyPI))
             }
+            CheckCategory::PandasVet => Some((
+                "https://pypi.org/project/pandas-vet/0.2.3/",
+                &Platform::PyPI,
+            )),
             CheckCategory::PEP8Naming => Some((
                 "https://pypi.org/project/pep8-naming/0.13.2/",
                 &Platform::PyPI,
@@ -541,6 +573,7 @@ pub enum LintSource {
     Lines,
     Tokens,
     Imports,
+    NoQA,
 }
 
 #[derive(Debug, PartialEq, Eq, Serialize, Deserialize)]
@@ -740,7 +773,7 @@ pub enum CheckKind {
     MissingTypeCls(String),
     MissingReturnTypePublicFunction(String),
     MissingReturnTypePrivateFunction(String),
-    MissingReturnTypeMagicMethod(String),
+    MissingReturnTypeSpecialMethod(String),
     MissingReturnTypeStaticMethod(String),
     MissingReturnTypeClassMethod(String),
     DynamicallyTypedExpression(String),
@@ -772,6 +805,7 @@ pub enum CheckKind {
     ConvertTypedDictFunctionalToClass(String),
     ConvertNamedTupleFunctionalToClass(String),
     RedundantOpenModes,
+    RemoveSixCompat,
     // pydocstyle
     BlankLineAfterLastSection(String),
     BlankLineAfterSection(String),
@@ -861,6 +895,23 @@ pub enum CheckKind {
     UnusedLambdaArgument(String),
     // flake8-import-conventions
     ImportAliasIsNotConventional(String, String),
+    // pandas-vet
+    UseOfInplaceArgument,
+    UseOfDotIsNull,
+    UseOfDotNotNull,
+    UseOfDotIx,
+    UseOfDotAt,
+    UseOfDotIat,
+    UseOfDotPivotOrUnstack,
+    UseOfDotValues,
+    UseOfDotReadTable,
+    UseOfDotStack,
+    UseOfPdMerge,
+    DfIsABadVariableName,
+    // flake8-errmsg
+    RawStringInException,
+    FStringInException,
+    DotFormatInException,
     // Ruff
     AmbiguousUnicodeCharacterString(char, char),
     AmbiguousUnicodeCharacterDocstring(char, char),
@@ -873,9 +924,8 @@ impl CheckCode {
     /// physical lines).
     pub fn lint_source(&self) -> &'static LintSource {
         match self {
-            CheckCode::E501 | CheckCode::W292 | CheckCode::RUF100 | CheckCode::UP009 => {
-                &LintSource::Lines
-            }
+            CheckCode::RUF100 => &LintSource::NoQA,
+            CheckCode::E501 | CheckCode::W292 | CheckCode::UP009 => &LintSource::Lines,
             CheckCode::ERA001
             | CheckCode::Q000
             | CheckCode::Q001
@@ -1076,7 +1126,7 @@ impl CheckCode {
             CheckCode::ANN102 => CheckKind::MissingTypeCls("...".to_string()),
             CheckCode::ANN201 => CheckKind::MissingReturnTypePublicFunction("...".to_string()),
             CheckCode::ANN202 => CheckKind::MissingReturnTypePrivateFunction("...".to_string()),
-            CheckCode::ANN204 => CheckKind::MissingReturnTypeMagicMethod("...".to_string()),
+            CheckCode::ANN204 => CheckKind::MissingReturnTypeSpecialMethod("...".to_string()),
             CheckCode::ANN205 => CheckKind::MissingReturnTypeStaticMethod("...".to_string()),
             CheckCode::ANN206 => CheckKind::MissingReturnTypeClassMethod("...".to_string()),
             CheckCode::ANN401 => CheckKind::DynamicallyTypedExpression("...".to_string()),
@@ -1113,6 +1163,7 @@ impl CheckCode {
             CheckCode::UP013 => CheckKind::ConvertTypedDictFunctionalToClass("...".to_string()),
             CheckCode::UP014 => CheckKind::ConvertNamedTupleFunctionalToClass("...".to_string()),
             CheckCode::UP015 => CheckKind::RedundantOpenModes,
+            CheckCode::UP016 => CheckKind::RemoveSixCompat,
             // pydocstyle
             CheckCode::D100 => CheckKind::PublicModule,
             CheckCode::D101 => CheckKind::PublicClass,
@@ -1219,6 +1270,23 @@ impl CheckCode {
             CheckCode::ICN001 => {
                 CheckKind::ImportAliasIsNotConventional("...".to_string(), "...".to_string())
             }
+            // pandas-vet
+            CheckCode::PDV002 => CheckKind::UseOfInplaceArgument,
+            CheckCode::PDV003 => CheckKind::UseOfDotIsNull,
+            CheckCode::PDV004 => CheckKind::UseOfDotNotNull,
+            CheckCode::PDV007 => CheckKind::UseOfDotIx,
+            CheckCode::PDV008 => CheckKind::UseOfDotAt,
+            CheckCode::PDV009 => CheckKind::UseOfDotIat,
+            CheckCode::PDV010 => CheckKind::UseOfDotPivotOrUnstack,
+            CheckCode::PDV011 => CheckKind::UseOfDotValues,
+            CheckCode::PDV012 => CheckKind::UseOfDotReadTable,
+            CheckCode::PDV013 => CheckKind::UseOfDotStack,
+            CheckCode::PDV015 => CheckKind::UseOfPdMerge,
+            CheckCode::PDV901 => CheckKind::DfIsABadVariableName,
+            // flake8-errmsg
+            CheckCode::EM101 => CheckKind::RawStringInException,
+            CheckCode::EM102 => CheckKind::FStringInException,
+            CheckCode::EM103 => CheckKind::DotFormatInException,
             // Ruff
             CheckCode::RUF001 => CheckKind::AmbiguousUnicodeCharacterString('𝐁', 'B'),
             CheckCode::RUF002 => CheckKind::AmbiguousUnicodeCharacterDocstring('𝐁', 'B'),
@@ -1354,6 +1422,9 @@ impl CheckCode {
             CheckCode::E743 => CheckCategory::Pycodestyle,
             CheckCode::E902 => CheckCategory::Pycodestyle,
             CheckCode::E999 => CheckCategory::Pycodestyle,
+            CheckCode::EM101 => CheckCategory::Flake8ErrMsg,
+            CheckCode::EM102 => CheckCategory::Flake8ErrMsg,
+            CheckCode::EM103 => CheckCategory::Flake8ErrMsg,
             CheckCode::ERA001 => CheckCategory::Eradicate,
             CheckCode::F401 => CheckCategory::Pyflakes,
             CheckCode::F402 => CheckCategory::Pyflakes,
@@ -1420,6 +1491,18 @@ impl CheckCode {
             CheckCode::N816 => CheckCategory::PEP8Naming,
             CheckCode::N817 => CheckCategory::PEP8Naming,
             CheckCode::N818 => CheckCategory::PEP8Naming,
+            CheckCode::PDV002 => CheckCategory::PandasVet,
+            CheckCode::PDV003 => CheckCategory::PandasVet,
+            CheckCode::PDV004 => CheckCategory::PandasVet,
+            CheckCode::PDV007 => CheckCategory::PandasVet,
+            CheckCode::PDV008 => CheckCategory::PandasVet,
+            CheckCode::PDV009 => CheckCategory::PandasVet,
+            CheckCode::PDV010 => CheckCategory::PandasVet,
+            CheckCode::PDV011 => CheckCategory::PandasVet,
+            CheckCode::PDV012 => CheckCategory::PandasVet,
+            CheckCode::PDV013 => CheckCategory::PandasVet,
+            CheckCode::PDV015 => CheckCategory::PandasVet,
+            CheckCode::PDV901 => CheckCategory::PandasVet,
             CheckCode::PGH001 => CheckCategory::PygrepHooks,
             CheckCode::PLC0414 => CheckCategory::Pylint,
             CheckCode::PLC2201 => CheckCategory::Pylint,
@@ -1473,6 +1556,7 @@ impl CheckCode {
             CheckCode::UP013 => CheckCategory::Pyupgrade,
             CheckCode::UP014 => CheckCategory::Pyupgrade,
             CheckCode::UP015 => CheckCategory::Pyupgrade,
+            CheckCode::UP016 => CheckCategory::Pyupgrade,
             CheckCode::W292 => CheckCategory::Pycodestyle,
             CheckCode::W605 => CheckCategory::Pycodestyle,
             CheckCode::YTT101 => CheckCategory::Flake82020,
@@ -1649,7 +1733,7 @@ impl CheckKind {
             CheckKind::MissingTypeCls(_) => &CheckCode::ANN102,
             CheckKind::MissingReturnTypePublicFunction(_) => &CheckCode::ANN201,
             CheckKind::MissingReturnTypePrivateFunction(_) => &CheckCode::ANN202,
-            CheckKind::MissingReturnTypeMagicMethod(_) => &CheckCode::ANN204,
+            CheckKind::MissingReturnTypeSpecialMethod(_) => &CheckCode::ANN204,
             CheckKind::MissingReturnTypeStaticMethod(_) => &CheckCode::ANN205,
             CheckKind::MissingReturnTypeClassMethod(_) => &CheckCode::ANN206,
             CheckKind::DynamicallyTypedExpression(_) => &CheckCode::ANN401,
@@ -1681,6 +1765,7 @@ impl CheckKind {
             CheckKind::ConvertTypedDictFunctionalToClass(_) => &CheckCode::UP013,
             CheckKind::ConvertNamedTupleFunctionalToClass(_) => &CheckCode::UP014,
             CheckKind::RedundantOpenModes => &CheckCode::UP015,
+            CheckKind::RemoveSixCompat => &CheckCode::UP016,
             // pydocstyle
             CheckKind::BlankLineAfterLastSection(_) => &CheckCode::D413,
             CheckKind::BlankLineAfterSection(_) => &CheckCode::D410,
@@ -1770,6 +1855,23 @@ impl CheckKind {
             CheckKind::UnusedLambdaArgument(..) => &CheckCode::ARG005,
             // flake8-import-conventions
             CheckKind::ImportAliasIsNotConventional(..) => &CheckCode::ICN001,
+            // pandas-vet
+            CheckKind::UseOfInplaceArgument => &CheckCode::PDV002,
+            CheckKind::UseOfDotIsNull => &CheckCode::PDV003,
+            CheckKind::UseOfDotNotNull => &CheckCode::PDV004,
+            CheckKind::UseOfDotIx => &CheckCode::PDV007,
+            CheckKind::UseOfDotAt => &CheckCode::PDV008,
+            CheckKind::UseOfDotIat => &CheckCode::PDV009,
+            CheckKind::UseOfDotPivotOrUnstack => &CheckCode::PDV010,
+            CheckKind::UseOfDotValues => &CheckCode::PDV011,
+            CheckKind::UseOfDotReadTable => &CheckCode::PDV012,
+            CheckKind::UseOfDotStack => &CheckCode::PDV013,
+            CheckKind::UseOfPdMerge => &CheckCode::PDV015,
+            CheckKind::DfIsABadVariableName => &CheckCode::PDV901,
+            // flake8-errmsg
+            CheckKind::RawStringInException => &CheckCode::EM101,
+            CheckKind::FStringInException => &CheckCode::EM102,
+            CheckKind::DotFormatInException => &CheckCode::EM103,
             // Ruff
             CheckKind::AmbiguousUnicodeCharacterString(..) => &CheckCode::RUF001,
             CheckKind::AmbiguousUnicodeCharacterDocstring(..) => &CheckCode::RUF002,
@@ -2288,8 +2390,8 @@ impl CheckKind {
             CheckKind::MissingReturnTypePrivateFunction(name) => {
                 format!("Missing return type annotation for private function `{name}`")
             }
-            CheckKind::MissingReturnTypeMagicMethod(name) => {
-                format!("Missing return type annotation for magic method `{name}`")
+            CheckKind::MissingReturnTypeSpecialMethod(name) => {
+                format!("Missing return type annotation for special method `{name}`")
             }
             CheckKind::MissingReturnTypeStaticMethod(name) => {
                 format!("Missing return type annotation for staticmethod `{name}`")
@@ -2372,6 +2474,7 @@ impl CheckKind {
             }
             CheckKind::UnnecessaryEncodeUTF8 => "Unnecessary call to `encode` as UTF-8".to_string(),
             CheckKind::RedundantOpenModes => "Unnecessary open mode parameters".to_string(),
+            CheckKind::RemoveSixCompat => "Unnecessary `six` compatibility usage".to_string(),
             CheckKind::ConvertTypedDictFunctionalToClass(name) => {
                 format!("Convert `{name}` from `TypedDict` functional to class syntax")
             }
@@ -2597,6 +2700,51 @@ impl CheckKind {
             CheckKind::ImportAliasIsNotConventional(name, asname) => {
                 format!("`{name}` should be imported as `{asname}`")
             }
+            // pandas-vet
+            CheckKind::UseOfInplaceArgument => {
+                "`inplace=True` should be avoided; it has inconsistent behavior".to_string()
+            }
+            CheckKind::UseOfDotIsNull => {
+                "`.isna` is preferred to `.isnull`; functionality is equivalent".to_string()
+            }
+            CheckKind::UseOfDotNotNull => {
+                "`.notna` is preferred to `.notnull`; functionality is equivalent".to_string()
+            }
+            CheckKind::UseOfDotIx => {
+                "``ix` i` deprecated; use more explicit `.loc` o` `.iloc`".to_string()
+            }
+            CheckKind::UseOfDotAt => {
+                "Use `.loc` instead of `.at`.  If speed is important, use numpy.".to_string()
+            }
+            CheckKind::UseOfDotIat => {
+                "Use `.iloc` instea` of `.iat`.  If speed is important, use numpy.".to_string()
+            }
+            CheckKind::UseOfDotPivotOrUnstack => "`.pivot_table` is preferred to `.pivot` or \
+                                                  `.unstack`; provides same functionality"
+                .to_string(),
+            CheckKind::UseOfDotValues => "Use `.to_numpy()` instead of `.values`".to_string(),
+            CheckKind::UseOfDotReadTable => {
+                "`.read_csv` is preferred to `.read_table`; provides same functionality".to_string()
+            }
+            CheckKind::UseOfDotStack => {
+                "`.melt` is preferred to `.stack`; provides same functionality".to_string()
+            }
+            CheckKind::DfIsABadVariableName => {
+                "`df` is a bad variable name. Be kinder to your future self.".to_string()
+            }
+            CheckKind::UseOfPdMerge => "Use `.merge` method instead of `pd.merge` function. They \
+                                        have equivalent functionality."
+                .to_string(),
+            // flake8-errmsg
+            CheckKind::RawStringInException => {
+                "Exception must not use a string literal, assign to variable first".to_string()
+            }
+            CheckKind::FStringInException => {
+                "Exception must not use an f-string literal, assign to variable first".to_string()
+            }
+            CheckKind::DotFormatInException => "Exception must not use a `.format()` string \
+                                                directly, assign to variable first"
+                .to_string(),
             // Ruff
             CheckKind::AmbiguousUnicodeCharacterString(confusable, representant) => {
                 format!(
@@ -2682,6 +2830,7 @@ impl CheckKind {
                 | CheckKind::IsLiteral
                 | CheckKind::KeyInDict(..)
                 | CheckKind::MisplacedComparisonConstant(..)
+                | CheckKind::MissingReturnTypeSpecialMethod(..)
                 | CheckKind::NewLineAfterLastParagraph
                 | CheckKind::NewLineAfterSectionName(..)
                 | CheckKind::NoBlankLineAfterFunction(..)
@@ -2696,13 +2845,14 @@ impl CheckKind {
                 | CheckKind::NotIsTest
                 | CheckKind::OneBlankLineAfterClass(..)
                 | CheckKind::OneBlankLineBeforeClass(..)
-                | CheckKind::PercentFormatExtraNamedArguments(..)
                 | CheckKind::PEP3120UnnecessaryCodingComment
                 | CheckKind::PPrintFound
+                | CheckKind::PercentFormatExtraNamedArguments(..)
                 | CheckKind::PrintFound
                 | CheckKind::RaiseNotImplemented
                 | CheckKind::RedundantOpenModes
                 | CheckKind::RedundantTupleInExceptionHandler(..)
+                | CheckKind::RemoveSixCompat
                 | CheckKind::SectionNameEndsInColon(..)
                 | CheckKind::SectionNotOverIndented(..)
                 | CheckKind::SectionUnderlineAfterName(..)
@@ -2785,6 +2935,7 @@ pub static CODE_REDIRECTS: Lazy<FxHashMap<&'static str, CheckCode>> = Lazy::new(
         ("U013", CheckCode::UP013),
         ("U014", CheckCode::UP014),
         ("U015", CheckCode::UP015),
+        ("U016", CheckCode::UP016),
         // TODO(charlie): Remove by 2023-02-01.
         ("I252", CheckCode::TID252),
         ("M001", CheckCode::RUF100),

src/checks_gen.rs

@@ -189,6 +189,12 @@ pub enum CheckCodePrefix {
     E902,
     E99,
     E999,
+    EM,
+    EM1,
+    EM10,
+    EM101,
+    EM102,
+    EM103,
     ERA,
     ERA0,
     ERA00,
@@ -297,6 +303,24 @@ pub enum CheckCodePrefix {
     N816,
     N817,
     N818,
+    PDV,
+    PDV0,
+    PDV00,
+    PDV002,
+    PDV003,
+    PDV004,
+    PDV007,
+    PDV008,
+    PDV009,
+    PDV01,
+    PDV010,
+    PDV011,
+    PDV012,
+    PDV013,
+    PDV015,
+    PDV9,
+    PDV90,
+    PDV901,
     PGH,
     PGH0,
     PGH00,
@@ -416,6 +440,7 @@ pub enum CheckCodePrefix {
     U013,
     U014,
     U015,
+    U016,
     UP,
     UP0,
     UP00,
@@ -434,6 +459,7 @@ pub enum CheckCodePrefix {
     UP013,
     UP014,
     UP015,
+    UP016,
     W,
     W2,
     W29,
@@ -1003,6 +1029,12 @@ impl CheckCodePrefix {
             CheckCodePrefix::E902 => vec![CheckCode::E902],
             CheckCodePrefix::E99 => vec![CheckCode::E999],
             CheckCodePrefix::E999 => vec![CheckCode::E999],
+            CheckCodePrefix::EM => vec![CheckCode::EM101, CheckCode::EM102, CheckCode::EM103],
+            CheckCodePrefix::EM1 => vec![CheckCode::EM101, CheckCode::EM102, CheckCode::EM103],
+            CheckCodePrefix::EM10 => vec![CheckCode::EM101, CheckCode::EM102, CheckCode::EM103],
+            CheckCodePrefix::EM101 => vec![CheckCode::EM101],
+            CheckCodePrefix::EM102 => vec![CheckCode::EM102],
+            CheckCodePrefix::EM103 => vec![CheckCode::EM103],
             CheckCodePrefix::ERA => vec![CheckCode::ERA001],
             CheckCodePrefix::ERA0 => vec![CheckCode::ERA001],
             CheckCodePrefix::ERA00 => vec![CheckCode::ERA001],
@@ -1336,6 +1368,62 @@ impl CheckCodePrefix {
             CheckCodePrefix::N816 => vec![CheckCode::N816],
             CheckCodePrefix::N817 => vec![CheckCode::N817],
             CheckCodePrefix::N818 => vec![CheckCode::N818],
+            CheckCodePrefix::PDV => vec![
+                CheckCode::PDV002,
+                CheckCode::PDV003,
+                CheckCode::PDV004,
+                CheckCode::PDV007,
+                CheckCode::PDV008,
+                CheckCode::PDV009,
+                CheckCode::PDV010,
+                CheckCode::PDV011,
+                CheckCode::PDV012,
+                CheckCode::PDV013,
+                CheckCode::PDV015,
+                CheckCode::PDV901,
+            ],
+            CheckCodePrefix::PDV0 => vec![
+                CheckCode::PDV002,
+                CheckCode::PDV003,
+                CheckCode::PDV004,
+                CheckCode::PDV007,
+                CheckCode::PDV008,
+                CheckCode::PDV009,
+                CheckCode::PDV010,
+                CheckCode::PDV011,
+                CheckCode::PDV012,
+                CheckCode::PDV013,
+                CheckCode::PDV015,
+            ],
+            CheckCodePrefix::PDV00 => vec![
+                CheckCode::PDV002,
+                CheckCode::PDV003,
+                CheckCode::PDV004,
+                CheckCode::PDV007,
+                CheckCode::PDV008,
+                CheckCode::PDV009,
+            ],
+            CheckCodePrefix::PDV002 => vec![CheckCode::PDV002],
+            CheckCodePrefix::PDV003 => vec![CheckCode::PDV003],
+            CheckCodePrefix::PDV004 => vec![CheckCode::PDV004],
+            CheckCodePrefix::PDV007 => vec![CheckCode::PDV007],
+            CheckCodePrefix::PDV008 => vec![CheckCode::PDV008],
+            CheckCodePrefix::PDV009 => vec![CheckCode::PDV009],
+            CheckCodePrefix::PDV01 => vec![
+                CheckCode::PDV010,
+                CheckCode::PDV011,
+                CheckCode::PDV012,
+                CheckCode::PDV013,
+                CheckCode::PDV015,
+            ],
+            CheckCodePrefix::PDV010 => vec![CheckCode::PDV010],
+            CheckCodePrefix::PDV011 => vec![CheckCode::PDV011],
+            CheckCodePrefix::PDV012 => vec![CheckCode::PDV012],
+            CheckCodePrefix::PDV013 => vec![CheckCode::PDV013],
+            CheckCodePrefix::PDV015 => vec![CheckCode::PDV015],
+            CheckCodePrefix::PDV9 => vec![CheckCode::PDV901],
+            CheckCodePrefix::PDV90 => vec![CheckCode::PDV901],
+            CheckCodePrefix::PDV901 => vec![CheckCode::PDV901],
             CheckCodePrefix::PGH => vec![CheckCode::PGH001],
             CheckCodePrefix::PGH0 => vec![CheckCode::PGH001],
             CheckCodePrefix::PGH00 => vec![CheckCode::PGH001],
@@ -1536,6 +1624,7 @@ impl CheckCodePrefix {
                     CheckCode::UP013,
                     CheckCode::UP014,
                     CheckCode::UP015,
+                    CheckCode::UP016,
                 ]
             }
             CheckCodePrefix::U0 => {
@@ -1560,6 +1649,7 @@ impl CheckCodePrefix {
                     CheckCode::UP013,
                     CheckCode::UP014,
                     CheckCode::UP015,
+                    CheckCode::UP016,
                 ]
             }
             CheckCodePrefix::U00 => {
@@ -1666,6 +1756,7 @@ impl CheckCodePrefix {
                     CheckCode::UP013,
                     CheckCode::UP014,
                     CheckCode::UP015,
+                    CheckCode::UP016,
                 ]
             }
             CheckCodePrefix::U010 => {
@@ -1722,6 +1813,15 @@ impl CheckCodePrefix {
                 );
                 vec![CheckCode::UP015]
             }
+            CheckCodePrefix::U016 => {
+                eprintln!(
+                    "{}{} {}",
+                    "warning".yellow().bold(),
+                    ":".bold(),
+                    "`U016` has been remapped to `UP016`".bold()
+                );
+                vec![CheckCode::UP016]
+            }
             CheckCodePrefix::UP => vec![
                 CheckCode::UP001,
                 CheckCode::UP003,
@@ -1737,6 +1837,7 @@ impl CheckCodePrefix {
                 CheckCode::UP013,
                 CheckCode::UP014,
                 CheckCode::UP015,
+                CheckCode::UP016,
             ],
             CheckCodePrefix::UP0 => vec![
                 CheckCode::UP001,
@@ -1753,6 +1854,7 @@ impl CheckCodePrefix {
                 CheckCode::UP013,
                 CheckCode::UP014,
                 CheckCode::UP015,
+                CheckCode::UP016,
             ],
             CheckCodePrefix::UP00 => vec![
                 CheckCode::UP001,
@@ -1779,6 +1881,7 @@ impl CheckCodePrefix {
                 CheckCode::UP013,
                 CheckCode::UP014,
                 CheckCode::UP015,
+                CheckCode::UP016,
             ],
             CheckCodePrefix::UP010 => vec![CheckCode::UP010],
             CheckCodePrefix::UP011 => vec![CheckCode::UP011],
@@ -1786,6 +1889,7 @@ impl CheckCodePrefix {
             CheckCodePrefix::UP013 => vec![CheckCode::UP013],
             CheckCodePrefix::UP014 => vec![CheckCode::UP014],
             CheckCodePrefix::UP015 => vec![CheckCode::UP015],
+            CheckCodePrefix::UP016 => vec![CheckCode::UP016],
             CheckCodePrefix::W => vec![CheckCode::W292, CheckCode::W605],
             CheckCodePrefix::W2 => vec![CheckCode::W292],
             CheckCodePrefix::W29 => vec![CheckCode::W292],
@@ -2018,6 +2122,12 @@ impl CheckCodePrefix {
             CheckCodePrefix::E902 => SuffixLength::Three,
             CheckCodePrefix::E99 => SuffixLength::Two,
             CheckCodePrefix::E999 => SuffixLength::Three,
+            CheckCodePrefix::EM => SuffixLength::Zero,
+            CheckCodePrefix::EM1 => SuffixLength::One,
+            CheckCodePrefix::EM10 => SuffixLength::Two,
+            CheckCodePrefix::EM101 => SuffixLength::Three,
+            CheckCodePrefix::EM102 => SuffixLength::Three,
+            CheckCodePrefix::EM103 => SuffixLength::Three,
             CheckCodePrefix::ERA => SuffixLength::Zero,
             CheckCodePrefix::ERA0 => SuffixLength::One,
             CheckCodePrefix::ERA00 => SuffixLength::Two,
@@ -2126,6 +2236,24 @@ impl CheckCodePrefix {
             CheckCodePrefix::N816 => SuffixLength::Three,
             CheckCodePrefix::N817 => SuffixLength::Three,
             CheckCodePrefix::N818 => SuffixLength::Three,
+            CheckCodePrefix::PDV => SuffixLength::Zero,
+            CheckCodePrefix::PDV0 => SuffixLength::One,
+            CheckCodePrefix::PDV00 => SuffixLength::Two,
+            CheckCodePrefix::PDV002 => SuffixLength::Three,
+            CheckCodePrefix::PDV003 => SuffixLength::Three,
+            CheckCodePrefix::PDV004 => SuffixLength::Three,
+            CheckCodePrefix::PDV007 => SuffixLength::Three,
+            CheckCodePrefix::PDV008 => SuffixLength::Three,
+            CheckCodePrefix::PDV009 => SuffixLength::Three,
+            CheckCodePrefix::PDV01 => SuffixLength::Two,
+            CheckCodePrefix::PDV010 => SuffixLength::Three,
+            CheckCodePrefix::PDV011 => SuffixLength::Three,
+            CheckCodePrefix::PDV012 => SuffixLength::Three,
+            CheckCodePrefix::PDV013 => SuffixLength::Three,
+            CheckCodePrefix::PDV015 => SuffixLength::Three,
+            CheckCodePrefix::PDV9 => SuffixLength::One,
+            CheckCodePrefix::PDV90 => SuffixLength::Two,
+            CheckCodePrefix::PDV901 => SuffixLength::Three,
             CheckCodePrefix::PGH => SuffixLength::Zero,
             CheckCodePrefix::PGH0 => SuffixLength::One,
             CheckCodePrefix::PGH00 => SuffixLength::Two,
@@ -2245,6 +2373,7 @@ impl CheckCodePrefix {
             CheckCodePrefix::U013 => SuffixLength::Three,
             CheckCodePrefix::U014 => SuffixLength::Three,
             CheckCodePrefix::U015 => SuffixLength::Three,
+            CheckCodePrefix::U016 => SuffixLength::Three,
             CheckCodePrefix::UP => SuffixLength::Zero,
             CheckCodePrefix::UP0 => SuffixLength::One,
             CheckCodePrefix::UP00 => SuffixLength::Two,
@@ -2263,6 +2392,7 @@ impl CheckCodePrefix {
             CheckCodePrefix::UP013 => SuffixLength::Three,
             CheckCodePrefix::UP014 => SuffixLength::Three,
             CheckCodePrefix::UP015 => SuffixLength::Three,
+            CheckCodePrefix::UP016 => SuffixLength::Three,
             CheckCodePrefix::W => SuffixLength::Zero,
             CheckCodePrefix::W2 => SuffixLength::One,
             CheckCodePrefix::W29 => SuffixLength::Two,
@@ -2300,12 +2430,14 @@ pub const CATEGORIES: &[CheckCodePrefix] = &[
     CheckCodePrefix::C,
     CheckCodePrefix::D,
     CheckCodePrefix::E,
+    CheckCodePrefix::EM,
     CheckCodePrefix::ERA,
     CheckCodePrefix::F,
     CheckCodePrefix::FBT,
     CheckCodePrefix::I,
     CheckCodePrefix::ICN,
     CheckCodePrefix::N,
+    CheckCodePrefix::PDV,
     CheckCodePrefix::PGH,
     CheckCodePrefix::PLC,
     CheckCodePrefix::PLE,

src/cli.rs

@@ -1,4 +1,4 @@
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
 
 use clap::{command, Parser};
 use regex::Regex;
@@ -6,6 +6,7 @@ use rustc_hash::FxHashMap;
 
 use crate::checks::CheckCode;
 use crate::checks_gen::CheckCodePrefix;
+use crate::fs;
 use crate::logging::LogLevel;
 use crate::settings::types::{
     FilePattern, PatternPrefixPair, PerFileIgnore, PythonVersion, SerializationFormat,
@@ -85,10 +86,16 @@ pub struct Cli {
     show_source: bool,
     #[clap(long, overrides_with("show_source"), hide = true)]
     no_show_source: bool,
+    /// Respect file exclusions via `.gitignore` and other standard ignore
+    /// files.
+    #[arg(long, overrides_with("no_respect_gitignore"))]
+    respect_gitignore: bool,
+    #[clap(long, overrides_with("respect_gitignore"), hide = true)]
+    no_respect_gitignore: bool,
     /// See the files Ruff will be run against with the current settings.
     #[arg(long)]
     pub show_files: bool,
-    /// See Ruff's settings.
+    /// See the settings Ruff will use to check a given Python file.
     #[arg(long)]
     pub show_settings: bool,
     /// Enable automatic additions of noqa directives to failing lines.
@@ -155,6 +162,10 @@ impl Cli {
                 line_length: self.line_length,
                 max_complexity: self.max_complexity,
                 per_file_ignores: self.per_file_ignores,
+                respect_gitignore: resolve_bool_arg(
+                    self.respect_gitignore,
+                    self.no_respect_gitignore,
+                ),
                 select: self.select,
                 show_source: resolve_bool_arg(self.show_source, self.no_show_source),
                 target_version: self.target_version,
@@ -198,6 +209,7 @@ pub struct Arguments {
 }
 
 /// CLI settings that function as configuration overrides.
+#[derive(Clone)]
 #[allow(clippy::struct_excessive_bools)]
 pub struct Overrides {
     pub dummy_variable_rgx: Option<Regex>,
@@ -210,6 +222,7 @@ pub struct Overrides {
     pub line_length: Option<usize>,
     pub max_complexity: Option<usize>,
     pub per_file_ignores: Option<Vec<PatternPrefixPair>>,
+    pub respect_gitignore: Option<bool>,
     pub select: Option<Vec<CheckCodePrefix>>,
     pub show_source: Option<bool>,
     pub target_version: Option<PythonVersion>,
@@ -243,6 +256,9 @@ pub fn collect_per_file_ignores(pairs: Vec<PatternPrefixPair>) -> Vec<PerFileIgn
     }
     per_file_ignores
         .into_iter()
-        .map(|(pattern, prefixes)| PerFileIgnore::new(pattern, &prefixes))
+        .map(|(pattern, prefixes)| {
+            let absolute = fs::normalize_path(Path::new(&pattern));
+            PerFileIgnore::new(pattern, absolute, &prefixes)
+        })
         .collect()
 }

src/commands.rs

@@ -1,36 +1,252 @@
-use std::path::PathBuf;
+use std::io::{self, Read};
+use std::path::{Path, PathBuf};
+use std::time::Instant;
 
 use anyhow::{bail, Result};
+use ignore::Error;
+use itertools::Itertools;
+use log::{debug, error};
+#[cfg(not(target_family = "wasm"))]
+use rayon::prelude::*;
+use rustpython_ast::Location;
 use serde::Serialize;
-use walkdir::DirEntry;
 
-use crate::checks::CheckCode;
-use crate::fs::iter_python_files;
+use crate::autofix::fixer;
+use crate::checks::{CheckCode, CheckKind};
+use crate::cli::Overrides;
+use crate::iterators::par_iter;
+use crate::linter::{add_noqa_to_path, autoformat_path, lint_path, lint_stdin, Diagnostics};
+use crate::message::Message;
+use crate::resolver::{FileDiscovery, PyprojectDiscovery};
+use crate::settings::flags;
 use crate::settings::types::SerializationFormat;
-use crate::{Configuration, Settings};
+use crate::{packages, resolver};
+
+/// Run the linter over a collection of files.
+pub fn run(
+    files: &[PathBuf],
+    pyproject_strategy: &PyprojectDiscovery,
+    file_strategy: &FileDiscovery,
+    overrides: &Overrides,
+    cache: flags::Cache,
+    autofix: fixer::Mode,
+) -> Result<Diagnostics> {
+    // Collect all the Python files to check.
+    let start = Instant::now();
+    let (paths, resolver) =
+        resolver::python_files_in_path(files, pyproject_strategy, file_strategy, overrides)?;
+    let duration = start.elapsed();
+    debug!("Identified files to lint in: {:?}", duration);
+
+    // Discover the package root for each Python file.
+    let package_roots = packages::detect_package_roots(
+        &paths
+            .iter()
+            .flatten()
+            .map(ignore::DirEntry::path)
+            .collect::<Vec<_>>(),
+    );
+
+    let start = Instant::now();
+    let mut diagnostics: Diagnostics = par_iter(&paths)
+        .map(|entry| {
+            match entry {
+                Ok(entry) => {
+                    let path = entry.path();
+                    let package = path
+                        .parent()
+                        .and_then(|parent| package_roots.get(parent))
+                        .and_then(|package| *package);
+                    let settings = resolver.resolve(path, pyproject_strategy);
+                    lint_path(path, package, settings, cache, autofix)
+                        .map_err(|e| (Some(path.to_owned()), e.to_string()))
+                }
+                Err(e) => Err((
+                    if let Error::WithPath { path, .. } = e {
+                        Some(path.clone())
+                    } else {
+                        None
+                    },
+                    e.io_error()
+                        .map_or_else(|| e.to_string(), io::Error::to_string),
+                )),
+            }
+            .unwrap_or_else(|(path, message)| {
+                if let Some(path) = &path {
+                    let settings = resolver.resolve(path, pyproject_strategy);
+                    if settings.enabled.contains(&CheckCode::E902) {
+                        Diagnostics::new(vec![Message {
+                            kind: CheckKind::IOError(message),
+                            location: Location::default(),
+                            end_location: Location::default(),
+                            fix: None,
+                            filename: path.to_string_lossy().to_string(),
+                            source: None,
+                        }])
+                    } else {
+                        error!("Failed to check {}: {message}", path.to_string_lossy());
+                        Diagnostics::default()
+                    }
+                } else {
+                    error!("{message}");
+                    Diagnostics::default()
+                }
+            })
+        })
+        .reduce(Diagnostics::default, |mut acc, item| {
+            acc += item;
+            acc
+        });
+
+    diagnostics.messages.sort_unstable();
+    let duration = start.elapsed();
+    debug!("Checked files in: {:?}", duration);
+
+    Ok(diagnostics)
+}
+
+/// Read a `String` from `stdin`.
+fn read_from_stdin() -> Result<String> {
+    let mut buffer = String::new();
+    io::stdin().lock().read_to_string(&mut buffer)?;
+    Ok(buffer)
+}
+
+/// Run the linter over a single file, read from `stdin`.
+pub fn run_stdin(
+    strategy: &PyprojectDiscovery,
+    filename: &Path,
+    autofix: fixer::Mode,
+) -> Result<Diagnostics> {
+    let stdin = read_from_stdin()?;
+    let settings = match strategy {
+        PyprojectDiscovery::Fixed(settings) => settings,
+        PyprojectDiscovery::Hierarchical(settings) => settings,
+    };
+    let mut diagnostics = lint_stdin(filename, &stdin, settings, autofix)?;
+    diagnostics.messages.sort_unstable();
+    Ok(diagnostics)
+}
+
+/// Add `noqa` directives to a collection of files.
+pub fn add_noqa(
+    files: &[PathBuf],
+    pyproject_strategy: &PyprojectDiscovery,
+    file_strategy: &FileDiscovery,
+    overrides: &Overrides,
+) -> Result<usize> {
+    // Collect all the files to check.
+    let start = Instant::now();
+    let (paths, resolver) =
+        resolver::python_files_in_path(files, pyproject_strategy, file_strategy, overrides)?;
+    let duration = start.elapsed();
+    debug!("Identified files to lint in: {:?}", duration);
+
+    let start = Instant::now();
+    let modifications: usize = par_iter(&paths)
+        .flatten()
+        .filter_map(|entry| {
+            let path = entry.path();
+            let settings = resolver.resolve(path, pyproject_strategy);
+            match add_noqa_to_path(path, settings) {
+                Ok(count) => Some(count),
+                Err(e) => {
+                    error!("Failed to add noqa to {}: {e}", path.to_string_lossy());
+                    None
+                }
+            }
+        })
+        .sum();
+
+    let duration = start.elapsed();
+    debug!("Added noqa to files in: {:?}", duration);
+
+    Ok(modifications)
+}
+
+/// Automatically format a collection of files.
+pub fn autoformat(
+    files: &[PathBuf],
+    pyproject_strategy: &PyprojectDiscovery,
+    file_strategy: &FileDiscovery,
+    overrides: &Overrides,
+) -> Result<usize> {
+    // Collect all the files to format.
+    let start = Instant::now();
+    let (paths, resolver) =
+        resolver::python_files_in_path(files, pyproject_strategy, file_strategy, overrides)?;
+    let duration = start.elapsed();
+    debug!("Identified files to lint in: {:?}", duration);
+
+    let start = Instant::now();
+    let modifications = par_iter(&paths)
+        .flatten()
+        .filter_map(|entry| {
+            let path = entry.path();
+            let settings = resolver.resolve(path, pyproject_strategy);
+            match autoformat_path(path, settings) {
+                Ok(()) => Some(()),
+                Err(e) => {
+                    error!("Failed to autoformat {}: {e}", path.to_string_lossy());
+                    None
+                }
+            }
+        })
+        .count();
+
+    let duration = start.elapsed();
+    debug!("Auto-formatted files in: {:?}", duration);
+
+    Ok(modifications)
+}
 
 /// Print the user-facing configuration settings.
 pub fn show_settings(
-    configuration: &Configuration,
-    project_root: Option<&PathBuf>,
-    pyproject: Option<&PathBuf>,
-) {
-    println!("Resolved configuration: {configuration:#?}");
-    println!("Found project root at: {project_root:?}");
-    println!("Found pyproject.toml at: {pyproject:?}");
+    files: &[PathBuf],
+    pyproject_strategy: &PyprojectDiscovery,
+    file_strategy: &FileDiscovery,
+    overrides: &Overrides,
+) -> Result<()> {
+    // Collect all files in the hierarchy.
+    let (paths, resolver) =
+        resolver::python_files_in_path(files, pyproject_strategy, file_strategy, overrides)?;
+
+    // Print the list of files.
+    let Some(entry) = paths
+        .iter()
+        .flatten()
+        .sorted_by(|a, b| a.path().cmp(b.path())).next() else {
+        bail!("No files found under the given path");
+    };
+    let path = entry.path();
+    let settings = resolver.resolve(path, pyproject_strategy);
+    println!("Resolved settings for: {path:?}");
+    println!("{settings:#?}");
+
+    Ok(())
 }
 
 /// Show the list of files to be checked based on current settings.
-pub fn show_files(files: &[PathBuf], settings: &Settings) {
-    let mut entries: Vec<DirEntry> = files
+pub fn show_files(
+    files: &[PathBuf],
+    pyproject_strategy: &PyprojectDiscovery,
+    file_strategy: &FileDiscovery,
+    overrides: &Overrides,
+) -> Result<()> {
+    // Collect all files in the hierarchy.
+    let (paths, _resolver) =
+        resolver::python_files_in_path(files, pyproject_strategy, file_strategy, overrides)?;
+
+    // Print the list of files.
+    for entry in paths
         .iter()
-        .flat_map(|path| iter_python_files(path, &settings.exclude, &settings.extend_exclude))
         .flatten()
-        .collect();
-    entries.sort_by(|a, b| a.path().cmp(b.path()));
-    for entry in entries {
+        .sorted_by(|a, b| a.path().cmp(b.path()))
+    {
         println!("{}", entry.path().to_string_lossy());
     }
+
+    Ok(())
 }
 
 #[derive(Serialize)]
@@ -41,7 +257,7 @@ struct Explanation<'a> {
 }
 
 /// Explain a `CheckCode` to the user.
-pub fn explain(code: &CheckCode, format: SerializationFormat) -> Result<()> {
+pub fn explain(code: &CheckCode, format: &SerializationFormat) -> Result<()> {
     match format {
         SerializationFormat::Text | SerializationFormat::Grouped => {
             println!(

src/directives.rs

@@ -37,6 +37,7 @@ pub struct IsortDirectives {
 }
 
 pub struct Directives {
+    pub commented_lines: Vec<usize>,
     pub noqa_line_for: IntMap<usize, usize>,
     pub isort: IsortDirectives,
 }
@@ -47,6 +48,7 @@ pub fn extract_directives(
     flags: Flags,
 ) -> Directives {
     Directives {
+        commented_lines: extract_commented_lines(lxr),
         noqa_line_for: if flags.contains(Flags::NOQA) {
             extract_noqa_line_for(lxr)
         } else {
@@ -60,6 +62,16 @@ pub fn extract_directives(
     }
 }
 
+pub fn extract_commented_lines(lxr: &[LexResult]) -> Vec<usize> {
+    let mut commented_lines = Vec::new();
+    for (start, tok, ..) in lxr.iter().flatten() {
+        if matches!(tok, Tok::Comment) {
+            commented_lines.push(start.row());
+        }
+    }
+    commented_lines
+}
+
 /// Extract a mapping from logical line to noqa line.
 pub fn extract_noqa_line_for(lxr: &[LexResult]) -> IntMap<usize, usize> {
     let mut noqa_line_for: IntMap<usize, usize> = IntMap::default();

src/eradicate/checks.rs

@@ -4,6 +4,7 @@ use crate::ast::types::Range;
 use crate::autofix::Fix;
 use crate::checks::{CheckCode, CheckKind};
 use crate::eradicate::detection::comment_contains_code;
+use crate::settings::flags;
 use crate::{Check, Settings, SourceCodeLocator};
 
 fn is_standalone_comment(line: &str) -> bool {
@@ -23,7 +24,7 @@ pub fn commented_out_code(
     start: Location,
     end: Location,
     settings: &Settings,
-    autofix: bool,
+    autofix: flags::Autofix,
 ) -> Option<Check> {
     let location = Location::new(start.row(), 0);
     let end_location = Location::new(end.row() + 1, 0);
@@ -41,7 +42,9 @@ pub fn commented_out_code(
                 end_location: end,
             },
         );
-        if autofix && settings.fixable.contains(&CheckCode::ERA001) {
+        if matches!(autofix, flags::Autofix::Enabled)
+            && settings.fixable.contains(&CheckCode::ERA001)
+        {
             check.amend(Fix::deletion(location, end_location));
         }
         Some(check)

src/eradicate/mod.rs

@@ -21,7 +21,6 @@ mod tests {
                 .join(path)
                 .as_path(),
             &settings::Settings::for_rule(check_code),
-            true,
         )?;
         checks.sort_by_key(|check| check.location);
         insta::assert_yaml_snapshot!(snapshot, checks);

src/flake8_2020/mod.rs

@@ -29,7 +29,6 @@ mod tests {
                 .join(path)
                 .as_path(),
             &settings::Settings::for_rule(check_code),
-            true,
         )?;
         checks.sort_by_key(|check| check.location);
         insta::assert_yaml_snapshot!(snapshot, checks);

src/flake8_2020/plugins.rs

@@ -3,7 +3,7 @@ use rustpython_ast::{Cmpop, Constant, Expr, ExprKind, Located};
 
 use crate::ast::helpers::match_module_member;
 use crate::ast::types::Range;
-use crate::check_ast::Checker;
+use crate::checkers::ast::Checker;
 use crate::checks::{Check, CheckCode, CheckKind};
 
 fn is_sys(checker: &Checker, expr: &Expr, target: &str) -> bool {

src/flake8_annotations/fixes.rs

@@ -0,0 +1,45 @@
+use anyhow::{bail, Result};
+use rustpython_ast::Stmt;
+use rustpython_parser::lexer;
+use rustpython_parser::lexer::Tok;
+
+use crate::ast::helpers;
+use crate::ast::types::Range;
+use crate::autofix::Fix;
+use crate::source_code_locator::SourceCodeLocator;
+
+/// ANN204
+pub fn add_return_none_annotation(locator: &SourceCodeLocator, stmt: &Stmt) -> Result<Fix> {
+    let range = Range::from_located(stmt);
+    let contents = locator.slice_source_code_range(&range);
+
+    // Find the colon (following the `def` keyword).
+    let mut seen_lpar = false;
+    let mut seen_rpar = false;
+    let mut count: usize = 0;
+    for (start, tok, ..) in lexer::make_tokenizer(&contents).flatten() {
+        if seen_lpar && seen_rpar {
+            if matches!(tok, Tok::Colon) {
+                return Ok(Fix::insertion(
+                    " -> None".to_string(),
+                    helpers::to_absolute(start, range.location),
+                ));
+            }
+        }
+
+        if matches!(tok, Tok::Lpar) {
+            if count == 0 {
+                seen_lpar = true;
+            }
+            count += 1;
+        }
+        if matches!(tok, Tok::Rpar) {
+            count -= 1;
+            if count == 0 {
+                seen_rpar = true;
+            }
+        }
+    }
+
+    bail!("Unable to locate colon in function definition");
+}

src/flake8_annotations/helpers.rs

@@ -1,7 +1,7 @@
 use rustpython_ast::{Arguments, Expr, Stmt, StmtKind};
 
 use crate::ast::cast;
-use crate::check_ast::Checker;
+use crate::checkers::ast::Checker;
 use crate::docstrings::definition::{Definition, DefinitionKind};
 use crate::visibility;
 

src/flake8_annotations/mod.rs

@@ -1,3 +1,4 @@
+mod fixes;
 pub mod helpers;
 pub mod plugins;
 pub mod settings;
@@ -31,7 +32,6 @@ mod tests {
                     CheckCode::ANN401,
                 ])
             },
-            true,
         )?;
         checks.sort_by_key(|check| check.location);
         insta::assert_yaml_snapshot!(checks);
@@ -57,7 +57,6 @@ mod tests {
                     CheckCode::ANN102,
                 ])
             },
-            true,
         )?;
         checks.sort_by_key(|check| check.location);
         insta::assert_yaml_snapshot!(checks);
@@ -83,7 +82,6 @@ mod tests {
                     CheckCode::ANN206,
                 ])
             },
-            true,
         )?;
         checks.sort_by_key(|check| check.location);
         insta::assert_yaml_snapshot!(checks);
@@ -109,7 +107,6 @@ mod tests {
                     CheckCode::ANN206,
                 ])
             },
-            true,
         )?;
         checks.sort_by_key(|check| check.location);
         insta::assert_yaml_snapshot!(checks);
@@ -129,7 +126,6 @@ mod tests {
                 },
                 ..Settings::for_rules(vec![CheckCode::ANN401])
             },
-            true,
         )?;
         checks.sort_by_key(|check| check.location);
         insta::assert_yaml_snapshot!(checks);
@@ -149,7 +145,6 @@ mod tests {
                     CheckCode::ANN206,
                 ])
             },
-            true,
         )?;
         checks.sort_by_key(|check| check.location);
         insta::assert_yaml_snapshot!(checks);

src/flake8_annotations/plugins.rs

@@ -1,11 +1,13 @@
+use log::error;
 use rustpython_ast::{Constant, Expr, ExprKind, Stmt, StmtKind};
 
 use crate::ast::types::Range;
 use crate::ast::visitor::Visitor;
 use crate::ast::{cast, visitor};
-use crate::check_ast::Checker;
+use crate::checkers::ast::Checker;
 use crate::checks::{CheckCode, CheckKind};
 use crate::docstrings::definition::{Definition, DefinitionKind};
+use crate::flake8_annotations::fixes;
 use crate::flake8_annotations::helpers::match_function_def;
 use crate::visibility::Visibility;
 use crate::{visibility, Check};
@@ -295,8 +297,8 @@ pub fn definition(checker: &mut Checker, definition: &Definition, visibility: &V
                     check_dynamically_typed(checker, expr, || name.to_string());
                 }
             } else {
-                // Allow omission of return annotation in `__init__` functions, if the function
-                // only returns `None` (explicitly or implicitly).
+                // Allow omission of return annotation if the function only returns `None`
+                // (explicitly or implicitly).
                 if checker.settings.flake8_annotations.suppress_none_returning
                     && is_none_returning(body)
                 {
@@ -317,13 +319,6 @@ pub fn definition(checker: &mut Checker, definition: &Definition, visibility: &V
                             Range::from_located(stmt),
                         ));
                     }
-                } else if visibility::is_magic(stmt) {
-                    if checker.settings.enabled.contains(&CheckCode::ANN204) {
-                        checker.add_check(Check::new(
-                            CheckKind::MissingReturnTypeMagicMethod(name.to_string()),
-                            Range::from_located(stmt),
-                        ));
-                    }
                 } else if visibility::is_init(stmt) {
                     // Allow omission of return annotation in `__init__` functions, as long as at
                     // least one argument is typed.
@@ -331,12 +326,26 @@ pub fn definition(checker: &mut Checker, definition: &Definition, visibility: &V
                         if !(checker.settings.flake8_annotations.mypy_init_return
                             && has_any_typed_arg)
                         {
-                            checker.add_check(Check::new(
-                                CheckKind::MissingReturnTypeMagicMethod(name.to_string()),
+                            let mut check = Check::new(
+                                CheckKind::MissingReturnTypeSpecialMethod(name.to_string()),
                                 Range::from_located(stmt),
-                            ));
+                            );
+                            if checker.patch(check.kind.code()) {
+                                match fixes::add_return_none_annotation(checker.locator, stmt) {
+                                    Ok(fix) => check.amend(fix),
+                                    Err(e) => error!("Failed to generate fix: {e}"),
+                                }
+                            }
+                            checker.add_check(check);
                         }
                     }
+                } else if visibility::is_magic(stmt) {
+                    if checker.settings.enabled.contains(&CheckCode::ANN204) {
+                        checker.add_check(Check::new(
+                            CheckKind::MissingReturnTypeSpecialMethod(name.to_string()),
+                            Range::from_located(stmt),
+                        ));
+                    }
                 } else {
                     match visibility {
                         Visibility::Public => {

src/flake8_annotations/snapshots/ruff__flake8_annotations__tests__allow_overload.snap

@@ -8,7 +8,7 @@ expression: checks
     row: 29
     column: 4
   end_location:
-    row: 35
-    column: 0
+    row: 30
+    column: 16
   fix: ~
 

src/flake8_annotations/snapshots/ruff__flake8_annotations__tests__defaults.snap

@@ -8,8 +8,8 @@ expression: checks
     row: 4
     column: 0
   end_location:
-    row: 9
-    column: 0
+    row: 5
+    column: 8
   fix: ~
 - kind:
     MissingTypeFunctionArgument: a
@@ -35,8 +35,8 @@ expression: checks
     row: 9
     column: 0
   end_location:
-    row: 14
-    column: 0
+    row: 10
+    column: 8
   fix: ~
 - kind:
     MissingTypeFunctionArgument: b
@@ -62,8 +62,8 @@ expression: checks
     row: 19
     column: 0
   end_location:
-    row: 24
-    column: 0
+    row: 20
+    column: 8
   fix: ~
 - kind:
     MissingReturnTypePublicFunction: foo
@@ -71,8 +71,8 @@ expression: checks
     row: 24
     column: 0
   end_location:
-    row: 29
-    column: 0
+    row: 25
+    column: 8
   fix: ~
 - kind:
     DynamicallyTypedExpression: a

src/flake8_annotations/snapshots/ruff__flake8_annotations__tests__mypy_init_return.snap

@@ -3,30 +3,44 @@ source: src/flake8_annotations/mod.rs
 expression: checks
 ---
 - kind:
-    MissingReturnTypeMagicMethod: __init__
+    MissingReturnTypeSpecialMethod: __init__
   location:
     row: 5
     column: 4
   end_location:
-    row: 10
-    column: 0
-  fix: ~
+    row: 6
+    column: 11
+  fix:
+    content: " -> None"
+    location:
+      row: 5
+      column: 22
+    end_location:
+      row: 5
+      column: 22
 - kind:
-    MissingReturnTypeMagicMethod: __init__
+    MissingReturnTypeSpecialMethod: __init__
   location:
     row: 11
     column: 4
   end_location:
-    row: 16
-    column: 0
-  fix: ~
+    row: 12
+    column: 11
+  fix:
+    content: " -> None"
+    location:
+      row: 11
+      column: 27
+    end_location:
+      row: 11
+      column: 27
 - kind:
     MissingReturnTypePrivateFunction: __init__
   location:
     row: 40
     column: 0
   end_location:
-    row: 42
-    column: 0
+    row: 41
+    column: 7
   fix: ~
 

src/flake8_annotations/snapshots/ruff__flake8_annotations__tests__suppress_none_returning.snap

@@ -8,8 +8,8 @@ expression: checks
     row: 45
     column: 0
   end_location:
-    row: 50
-    column: 0
+    row: 46
+    column: 15
   fix: ~
 - kind:
     MissingReturnTypePublicFunction: foo
@@ -17,7 +17,7 @@ expression: checks
     row: 50
     column: 0
   end_location:
-    row: 56
-    column: 0
+    row: 55
+    column: 14
   fix: ~
 

src/flake8_bandit/mod.rs

@@ -26,7 +26,6 @@ mod tests {
                 .join(path)
                 .as_path(),
             &settings::Settings::for_rule(check_code),
-            true,
         )?;
         checks.sort_by_key(|check| check.location);
         insta::assert_yaml_snapshot!(snapshot, checks);

src/flake8_blind_except/mod.rs

@@ -20,7 +20,6 @@ mod tests {
                 .join(path)
                 .as_path(),
             &settings::Settings::for_rule(check_code),
-            true,
         )?;
         checks.sort_by_key(|check| check.location);
         insta::assert_yaml_snapshot!(snapshot, checks);

src/flake8_blind_except/plugins.rs

@@ -1,7 +1,7 @@
 use rustpython_ast::{Expr, ExprKind, Stmt, StmtKind};
 
 use crate::ast::types::Range;
-use crate::check_ast::Checker;
+use crate::checkers::ast::Checker;
 use crate::checks::{Check, CheckKind};
 
 /// BLE001

src/flake8_boolean_trap/mod.rs

@@ -22,7 +22,6 @@ mod tests {
                 .join(path)
                 .as_path(),
             &settings::Settings::for_rule(check_code),
-            true,
         )?;
         checks.sort_by_key(|check| check.location);
         insta::assert_yaml_snapshot!(snapshot, checks);

src/flake8_boolean_trap/plugins.rs

@@ -2,7 +2,7 @@ use rustpython_ast::{Arguments, ExprKind};
 use rustpython_parser::ast::{Constant, Expr};
 
 use crate::ast::types::Range;
-use crate::check_ast::Checker;
+use crate::checkers::ast::Checker;
 use crate::checks::{Check, CheckKind};
 
 const FUNC_NAME_ALLOWLIST: &[&str] = &["get", "setdefault", "pop", "fromkeys"];

src/flake8_bugbear/mod.rs

@@ -47,7 +47,6 @@ mod tests {
                 .join(path)
                 .as_path(),
             &Settings::for_rule(check_code),
-            true,
         )?;
         checks.sort_by_key(|check| check.location);
         insta::assert_yaml_snapshot!(snapshot, checks);
@@ -68,7 +67,6 @@ mod tests {
                 },
                 ..Settings::for_rules(vec![CheckCode::B008])
             },
-            true,
         )?;
         checks.sort_by_key(|check| check.location);
         insta::assert_yaml_snapshot!(snapshot, checks);

src/flake8_bugbear/plugins/abstract_base_class.rs

@@ -3,7 +3,7 @@ use rustpython_ast::{Constant, Expr, ExprKind, Keyword, Stmt, StmtKind};
 
 use crate::ast::helpers::match_module_member;
 use crate::ast::types::Range;
-use crate::check_ast::Checker;
+use crate::checkers::ast::Checker;
 use crate::checks::{Check, CheckCode, CheckKind};
 
 fn is_abc_class(

src/flake8_bugbear/plugins/assert_false.rs

@@ -2,7 +2,7 @@ use rustpython_ast::{Constant, Expr, ExprContext, ExprKind, Location, Stmt, Stmt
 
 use crate::ast::types::Range;
 use crate::autofix::Fix;
-use crate::check_ast::Checker;
+use crate::checkers::ast::Checker;
 use crate::checks::{Check, CheckKind};
 use crate::code_gen::SourceGenerator;
 

src/flake8_bugbear/plugins/assert_raises_exception.rs

@@ -2,7 +2,7 @@ use rustpython_ast::{ExprKind, Stmt, Withitem};
 
 use crate::ast::helpers::match_module_member;
 use crate::ast::types::Range;
-use crate::check_ast::Checker;
+use crate::checkers::ast::Checker;
 use crate::checks::{Check, CheckKind};
 
 /// B017

src/flake8_bugbear/plugins/assignment_to_os_environ.rs

@@ -1,7 +1,7 @@
 use rustpython_ast::{Expr, ExprKind};
 
 use crate::ast::types::Range;
-use crate::check_ast::Checker;
+use crate::checkers::ast::Checker;
 use crate::checks::{Check, CheckKind};
 
 /// B003

src/flake8_bugbear/plugins/cached_instance_method.rs

@@ -2,7 +2,7 @@ use rustpython_ast::{Expr, ExprKind};
 
 use crate::ast::helpers::{collect_call_paths, dealias_call_path, match_call_path};
 use crate::ast::types::{Range, ScopeKind};
-use crate::check_ast::Checker;
+use crate::checkers::ast::Checker;
 use crate::checks::{Check, CheckKind};
 
 fn is_cache_func(checker: &Checker, expr: &Expr) -> bool {

src/flake8_bugbear/plugins/cannot_raise_literal.rs

@@ -1,7 +1,7 @@
 use rustpython_ast::{Expr, ExprKind};
 
 use crate::ast::types::Range;
-use crate::check_ast::Checker;
+use crate::checkers::ast::Checker;
 use crate::checks::{Check, CheckKind};
 
 /// B016

src/flake8_bugbear/plugins/duplicate_exceptions.rs

@@ -7,7 +7,7 @@ use rustpython_ast::{
 use crate::ast::helpers;
 use crate::ast::types::Range;
 use crate::autofix::Fix;
-use crate::check_ast::Checker;
+use crate::checkers::ast::Checker;
 use crate::checks::{Check, CheckCode, CheckKind};
 use crate::code_gen::SourceGenerator;
 

src/flake8_bugbear/plugins/f_string_docstring.rs

@@ -1,7 +1,7 @@
 use rustpython_ast::{ExprKind, Stmt, StmtKind};
 
 use crate::ast::types::Range;
-use crate::check_ast::Checker;
+use crate::checkers::ast::Checker;
 use crate::checks::{Check, CheckKind};
 
 /// B021

src/flake8_bugbear/plugins/function_call_argument_default.rs

@@ -7,7 +7,7 @@ use crate::ast::helpers::{
 use crate::ast::types::Range;
 use crate::ast::visitor;
 use crate::ast::visitor::Visitor;
-use crate::check_ast::Checker;
+use crate::checkers::ast::Checker;
 use crate::checks::{Check, CheckKind};
 use crate::flake8_bugbear::plugins::mutable_argument_default::is_mutable_func;
 

src/flake8_bugbear/plugins/function_uses_loop_variable.rs

@@ -5,7 +5,7 @@ use crate::ast::helpers::collect_arg_names;
 use crate::ast::types::{Node, Range};
 use crate::ast::visitor;
 use crate::ast::visitor::Visitor;
-use crate::check_ast::Checker;
+use crate::checkers::ast::Checker;
 use crate::checks::{Check, CheckKind};
 
 #[derive(Default)]

src/flake8_bugbear/plugins/getattr_with_constant.rs

@@ -2,7 +2,7 @@ use rustpython_ast::{Constant, Expr, ExprContext, ExprKind, Location};
 
 use crate::ast::types::Range;
 use crate::autofix::Fix;
-use crate::check_ast::Checker;
+use crate::checkers::ast::Checker;
 use crate::checks::{Check, CheckKind};
 use crate::code_gen::SourceGenerator;
 use crate::python::identifiers::IDENTIFIER_REGEX;

src/flake8_bugbear/plugins/jump_statement_in_finally.rs

@@ -1,7 +1,7 @@
 use rustpython_ast::{Stmt, StmtKind};
 
 use crate::ast::types::Range;
-use crate::check_ast::Checker;
+use crate::checkers::ast::Checker;
 use crate::checks::{Check, CheckKind};
 
 fn walk_stmt(checker: &mut Checker, body: &[Stmt], f: fn(&Stmt) -> bool) {

src/flake8_bugbear/plugins/loop_variable_overrides_iterator.rs

@@ -4,7 +4,7 @@ use rustpython_ast::{Expr, ExprKind};
 use crate::ast::types::Range;
 use crate::ast::visitor;
 use crate::ast::visitor::Visitor;
-use crate::check_ast::Checker;
+use crate::checkers::ast::Checker;
 use crate::checks::{Check, CheckKind};
 
 #[derive(Default)]

src/flake8_bugbear/plugins/mutable_argument_default.rs

@@ -3,7 +3,7 @@ use rustpython_ast::{Arguments, Constant, Expr, ExprKind, Operator};
 
 use crate::ast::helpers::{collect_call_paths, dealias_call_path, match_call_path};
 use crate::ast::types::Range;
-use crate::check_ast::Checker;
+use crate::checkers::ast::Checker;
 use crate::checks::{Check, CheckKind};
 
 const MUTABLE_FUNCS: &[(&str, &str)] = &[

src/flake8_bugbear/plugins/raise_without_from_inside_except.rs

@@ -2,7 +2,7 @@ use rustpython_ast::{ExprKind, Stmt, StmtKind};
 
 use crate::ast::types::Range;
 use crate::ast::visitor::Visitor;
-use crate::check_ast::Checker;
+use crate::checkers::ast::Checker;
 use crate::checks::{Check, CheckKind};
 use crate::python::string::is_lower;
 

src/flake8_bugbear/plugins/redundant_tuple_in_exception_handler.rs

@@ -7,7 +7,7 @@ use rustpython_parser::lexer::Tok;
 use crate::ast::helpers;
 use crate::ast::types::Range;
 use crate::autofix::Fix;
-use crate::check_ast::Checker;
+use crate::checkers::ast::Checker;
 use crate::checks::{Check, CheckKind};
 use crate::code_gen::SourceGenerator;
 use crate::SourceCodeLocator;

src/flake8_bugbear/plugins/setattr_with_constant.rs

@@ -4,7 +4,7 @@ use rustpython_ast::{Constant, Expr, ExprContext, ExprKind, Location, Stmt, Stmt
 
 use crate::ast::types::Range;
 use crate::autofix::Fix;
-use crate::check_ast::Checker;
+use crate::checkers::ast::Checker;
 use crate::checks::{Check, CheckKind};
 use crate::code_gen::SourceGenerator;
 use crate::python::identifiers::IDENTIFIER_REGEX;
@@ -56,16 +56,23 @@ pub fn setattr_with_constant(checker: &mut Checker, expr: &Expr, func: &Expr, ar
     if KWLIST.contains(&name.as_str()) {
         return;
     }
-    let mut check = Check::new(CheckKind::SetAttrWithConstant, Range::from_located(expr));
-    if checker.patch(check.kind.code()) {
-        match assignment(obj, name, value) {
-            Ok(content) => check.amend(Fix::replacement(
-                content,
-                expr.location,
-                expr.end_location.unwrap(),
-            )),
-            Err(e) => error!("Failed to fix invalid comparison: {e}"),
-        };
+    // We can only replace a `setattr` call (which is an `Expr`) with an assignment
+    // (which is a `Stmt`) if the `Expr` is already being used as a `Stmt`
+    // (i.e., it's directly within an `StmtKind::Expr`).
+    if let StmtKind::Expr { value: child } = &checker.current_parent().0.node {
+        if expr == child.as_ref() {
+            let mut check = Check::new(CheckKind::SetAttrWithConstant, Range::from_located(expr));
+            if checker.patch(check.kind.code()) {
+                match assignment(obj, name, value) {
+                    Ok(content) => check.amend(Fix::replacement(
+                        content,
+                        expr.location,
+                        expr.end_location.unwrap(),
+                    )),
+                    Err(e) => error!("Failed to fix invalid comparison: {e}"),
+                };
+            }
+            checker.add_check(check);
+        }
     }
-    checker.add_check(check);
 }