Bump version to 0.0.48

Cargo.lock

@@ -382,26 +382,24 @@ checksum = "fff857943da45f546682664a79488be82e69e43c1a7a2307679ab9afb3a66d2e"
 
 [[package]]
 name = "clap"
-version = "3.2.16"
+version = "4.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a3dbbb6653e7c55cc8595ad3e1f7be8f32aba4eb7ff7f0fd1163d4f3d137c0a9"
+checksum = "dd03107d0f87139c1774a15f3db2165b0652b5460c58c27e561f89c20c599eaf"
 dependencies = [
  "atty",
  "bitflags",
  "clap_derive",
  "clap_lex",
- "indexmap",
  "once_cell",
  "strsim",
  "termcolor",
- "textwrap",
 ]
 
 [[package]]
 name = "clap_derive"
-version = "3.2.15"
+version = "4.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9ba52acd3b0a5c33aeada5cdaa3267cdc7c594a98731d4268cdc1532f4264cb4"
+checksum = "ca689d7434ce44517a12a89456b2be4d1ea1cafcd8f581978c03d45f5a5c12a7"
 dependencies = [
  "heck",
  "proc-macro-error",
@@ -412,9 +410,9 @@ dependencies = [
 
 [[package]]
 name = "clap_lex"
-version = "0.2.4"
+version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2850f2f5a82cbf437dd5af4d49848fbdfc27c157c3d010345776f952765261c5"
+checksum = "0d4198f73e42b4936b35b5bb248d81d2b595ecb170da0bac7655c54eedfa8da8"
 dependencies = [
  "os_str_bytes",
 ]
@@ -1801,7 +1799,7 @@ dependencies = [
 
 [[package]]
 name = "ruff"
-version = "0.0.40"
+version = "0.0.48"
 dependencies = [
  "anyhow",
  "bincode",
@@ -1846,7 +1844,7 @@ dependencies = [
 [[package]]
 name = "rustpython-ast"
 version = "0.1.0"
-source = "git+https://github.com/charliermarsh/RustPython.git?rev=7d21c6923a506e79cc041708d83cef925efd33f4#7d21c6923a506e79cc041708d83cef925efd33f4"
+source = "git+https://github.com/charliermarsh/RustPython.git?rev=966a80597d626a9a47eaec78471164422d341453#966a80597d626a9a47eaec78471164422d341453"
 dependencies = [
  "num-bigint",
  "rustpython-compiler-core",
@@ -1855,7 +1853,7 @@ dependencies = [
 [[package]]
 name = "rustpython-compiler-core"
 version = "0.1.2"
-source = "git+https://github.com/charliermarsh/RustPython.git?rev=7d21c6923a506e79cc041708d83cef925efd33f4#7d21c6923a506e79cc041708d83cef925efd33f4"
+source = "git+https://github.com/charliermarsh/RustPython.git?rev=966a80597d626a9a47eaec78471164422d341453#966a80597d626a9a47eaec78471164422d341453"
 dependencies = [
  "bincode",
  "bitflags",
@@ -1872,7 +1870,7 @@ dependencies = [
 [[package]]
 name = "rustpython-parser"
 version = "0.1.2"
-source = "git+https://github.com/charliermarsh/RustPython.git?rev=7d21c6923a506e79cc041708d83cef925efd33f4#7d21c6923a506e79cc041708d83cef925efd33f4"
+source = "git+https://github.com/charliermarsh/RustPython.git?rev=966a80597d626a9a47eaec78471164422d341453#966a80597d626a9a47eaec78471164422d341453"
 dependencies = [
  "ahash",
  "anyhow",
@@ -2187,12 +2185,6 @@ dependencies = [
  "phf_codegen 0.8.0",
 ]
 
-[[package]]
-name = "textwrap"
-version = "0.15.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b1141d4d61095b28419e22cb0bbf02755f5e54e0526f97f1e3d1d160e60885fb"
-
 [[package]]
 name = "thiserror"
 version = "1.0.32"

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ruff"
-version = "0.0.40"
+version = "0.0.48"
 edition = "2021"
 
 [lib]
@@ -11,22 +11,22 @@ anyhow = { version = "1.0.60" }
 bincode = { version = "1.3.3" }
 cacache = { version = "10.0.1" }
 chrono = { version = "0.4.21" }
-clap = { version = "3.2.16", features = ["derive"] }
+clap = { version = "4.0.1", features = ["derive"] }
 clearscreen = { version = "1.0.10" }
 colored = { version = "2.0.0" }
 common-path = { version = "1.0.0" }
 dirs = { version = "4.0.0" }
 fern = { version = "0.6.1" }
 filetime = { version = "0.2.17" }
-glob = "0.3.0"
-itertools = "0.10.3"
+glob = { version = "0.3.0" }
+itertools = { version = "0.10.3" }
 log = { version = "0.4.17" }
 notify = { version = "4.0.17" }
 once_cell = { version = "1.13.1" }
 path-absolutize = { version = "3.0.13", features = ["once_cell_cache"] }
 rayon = { version = "1.5.3" }
 regex = { version = "1.6.0" }
-rustpython-parser = { features = ["lalrpop"], git = "https://github.com/charliermarsh/RustPython.git", rev = "7d21c6923a506e79cc041708d83cef925efd33f4" }
+rustpython-parser = { features = ["lalrpop"], git = "https://github.com/charliermarsh/RustPython.git", rev = "966a80597d626a9a47eaec78471164422d341453" }
 serde = { version = "1.0.143", features = ["derive"] }
 serde_json = { version = "1.0.83" }
 toml = { version = "0.5.9" }

README.md

@@ -20,11 +20,9 @@ An extremely fast Python linter, written in Rust.
 - 🤝 Python 3.10 compatibility
 - 🛠️ `pyproject.toml` support
 - 📦 [ESLint](https://eslint.org/docs/latest/user-guide/command-line-interface#caching)-inspired cache support
-- 🔧 [ESLint](https://eslint.org/docs/latest/user-guide/command-line-interface#caching)-inspired `--fix` support
+- 🔧 [ESLint](https://eslint.org/docs/latest/user-guide/command-line-interface#--fix)-inspired `--fix` support
 - 👀 [TypeScript](https://www.typescriptlang.org/docs/handbook/configuring-watch.html)-inspired `--watch` support
-
-_ruff is a proof-of-concept and not yet intended for production use. It supports only a small subset
-of the Flake8 rules, and may crash on your codebase._
+- ⚖️ [Near-complete parity](#Parity-with-Flake8) with the built-in Flake8 rule set
 
 Read the [launch blog post](https://notes.crmarsh.com/python-tooling-could-be-much-much-faster).
 
@@ -82,51 +80,64 @@ select = [
 Alternatively, on the command-line:
 
 ```shell
-ruff path/to/code/ --select F401 F403
+ruff path/to/code/ --select F401 --select F403
 ```
 
 See `ruff --help` for more:
 
 ```shell
-ruff (v0.0.40)
-An extremely fast Python linter.
+ruff: An extremely fast Python linter.
 
-USAGE:
-    ruff [OPTIONS] <FILES>...
+Usage: ruff [OPTIONS] <FILES>...
 
-ARGS:
-    <FILES>...
+Arguments:
+  <FILES>...
 
-OPTIONS:
-    -e, --exit-zero
-            Exit with status code "0", even upon detecting errors
-        --exclude <EXCLUDE>...
-            List of paths, used to exclude files and/or directories from checks
-        --extend-exclude <EXTEND_EXCLUDE>...
-            Like --exclude, but adds additional files and directories on top of the excluded ones
-    -f, --fix
-            Attempt to automatically fix lint errors
-        --format <FORMAT>
-            Output serialization format for error messages [default: text] [possible values: text,
-            json]
-    -h, --help
-            Print help information
-        --ignore <IGNORE>...
-            List of error codes to ignore
-    -n, --no-cache
-            Disable cache reads
-    -q, --quiet
-            Disable all logging (but still exit with status code "1" upon detecting errors)
-        --select <SELECT>...
-            List of error codes to enable
-    -v, --verbose
-            Enable verbose logging
-    -V, --version
-            Print version information
-    -w, --watch
-            Run in watch mode by re-running whenever files change
+Options:
+  -v, --verbose
+          Enable verbose logging
+  -q, --quiet
+          Disable all logging (but still exit with status code "1" upon detecting errors)
+  -e, --exit-zero
+          Exit with status code "0", even upon detecting errors
+  -w, --watch
+          Run in watch mode by re-running whenever files change
+  -f, --fix
+          Attempt to automatically fix lint errors
+  -n, --no-cache
+          Disable cache reads
+      --select <SELECT>
+          List of error codes to enable
+      --extend-select <EXTEND_SELECT>
+          Like --select, but adds additional error codes on top of the selected ones
+      --ignore <IGNORE>
+          List of error codes to ignore
+      --extend-ignore <EXTEND_IGNORE>
+          Like --ignore, but adds additional error codes on top of the ignored ones
+      --exclude <EXCLUDE>
+          List of paths, used to exclude files and/or directories from checks
+      --extend-exclude <EXTEND_EXCLUDE>
+          Like --exclude, but adds additional files and directories on top of the excluded ones
+      --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]
+      --show-files
+          See the files ruff will be run against with the current settings
+      --show-settings
+          See ruff's settings
+      --add-noqa
+          Enable automatic additions of noqa directives to failing lines
+      --dummy-variable-rgx <DUMMY_VARIABLE_RGX>
+          Regular expression matching the name of dummy variables
+  -h, --help
+          Print help information
+  -V, --version
+          Print version information
 ```
 
+### Excluding files
+
 Exclusions are based on globs, and can be either:
 
 - Single-path patterns, like `.mypy_cache` (to exclude any directory named `.mypy_cache` in the
@@ -136,35 +147,72 @@ 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`).
 
+### Ignoring errors
+
+To omit a lint check entirely, add it to the "ignore" list via `--ignore` or `--extend-ignore`,
+either  on the command-line or in your `project.toml` file.
+
+To ignore an error in-line, ruff uses a `noqa` system similar to [Flake8](https://flake8.pycqa.org/en/3.1.1/user/ignoring-errors.html).
+To ignore an individual error, add `# noqa: {code}` to the end of the line, like so:
+
+```python
+# Ignore F841.
+x = 1  # noqa: F841
+
+# Ignore E741 and F841.
+i = 1  # noqa: E741, F841
+
+# Ignore _all_ errors.
+x = 1  # noqa
+```
+
+Note that, for multi-line strings, the `noqa` directive should come at the end of the string, and
+will apply to the entire body, like so:
+
+```python
+"""Lorem ipsum dolor sit amet.
+
+Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
+"""  # noqa: E501
+```
+
+ruff supports several (experimental) workflows to aid in `noqa` management.
+
+First, ruff provides a special error code, `M001`, to enforce that your `noqa` directives are
+"valid", in that the errors they _say_ they ignore are actually being triggered on that line (and
+thus suppressed). **You can run `ruff /path/to/file.py --extend-select M001` to flag unused `noqa`
+directives.**
+
+Second, ruff can _automatically remove_ unused `noqa` directives via its autofix functionality.
+**You can run `ruff /path/to/file.py --extend-select M001 --fix` to automatically remove unused
+`noqa` directives.**
+
+Third, ruff can _automatically add_ `noqa` directives to all failing lines. This is useful when
+migrating a new codebase to ruff. **You can run `ruff /path/to/file.py --add-noqa` to automatically
+add `noqa` directives to all failing lines, with the appropriate error codes.**
+
 ### Compatibility with Black
 
-ruff is intended to be compatible with [Black](https://github.com/psf/black), and should be
-compatible out-of-the-box as long as the `line-length` setting is consistent between the two.
+ruff is compatible with [Black](https://github.com/psf/black) out-of-the-box, as long as
+the `line-length` setting is consistent between the two.
 
 As a project, ruff is designed to be used alongside Black and, as such, will defer implementing
-lint rules that are obviated by Black (e.g., stylistic rules).
+stylistic lint rules that are obviated by autoformatting.
 
 ### Parity with Flake8
 
-ruff's goal is to achieve feature-parity with Flake8 when used (1) without any plugins,
-(2) alongside Black, and (3) on Python 3 code. (Using Black obviates the need for many of Flake8's
-stylistic checks; limiting to Python 3 obviates the need for certain compatibility checks.)
+ruff's goal is to achieve feature-parity with Flake8 when used (1) without plugins, (2) alongside
+Black, and (3) on Python 3 code.
 
-Under those conditions, Flake8 implements about 60 rules, give or take. At time of writing, ruff
-implements 42 rules. (Note that these 42 rules likely cover a disproportionate share of errors:
-unused imports, undefined variables, etc.)
-
-The unimplemented rules are tracked in #170, and include:
-
-- 14 rules related to string `.format` calls.
-- 4 logical rules.
-- 1 rule related to parsing.
+**Under those conditions, ruff implements 44 out of 60 rules.** (ruff is missing: 14 rules related
+to string `.format` calls, 1 rule related to docstring parsing, and 1 rule related to redefined
+variables.)
 
 Beyond rule-set parity, ruff suffers from the following limitations vis-à-vis Flake8:
 
-1. Flake8 supports a wider range of `noqa` patterns, such as per-file ignores defined in `.flake8`.
-2. Flake8 has a plugin architecture and supports writing custom lint rules.
-3. ruff does not yet support parenthesized context managers.
+1. Flake8 has a plugin architecture and supports writing custom lint rules.
+2. ruff does not yet support a few Python 3.9 and 3.10 language features, including structural
+   pattern matching and parenthesized context managers.
 
 ## Rules
 
@@ -182,11 +230,13 @@ Beyond rule-set parity, ruff suffers from the following limitations vis-à-vis F
 | E741 | AmbiguousVariableName | ambiguous variable name '...' |
 | E742 | AmbiguousClassName | ambiguous class name '...' |
 | E743 | AmbiguousFunctionName | ambiguous function name '...' |
-| E902 | IOError | No such file or directory: `...` |
+| E902 | IOError | ... |
 | E999 | SyntaxError | SyntaxError: ... |
 | F401 | UnusedImport | `...` imported but unused |
-| F403 | ImportStarUsage | `from ... import *` used; unable to detect undefined names |
+| F402 | ImportShadowedByLoopVar | import '...' from line 1 shadowed by loop variable |
+| F403 | ImportStarUsed | `from ... import *` used; unable to detect undefined names |
 | F404 | LateFutureImport | from __future__ imports must occur at the beginning of the file |
+| F405 | ImportStarUsage | '...' may be undefined, or defined from star imports: ... |
 | F406 | ImportStarNotPermitted | `from ... import *` only allowed at module level |
 | F407 | FutureFeatureNotDefined | future feature '...' is not defined |
 | F541 | FStringMissingPlaceholders | f-string without any placeholders |
@@ -212,6 +262,7 @@ Beyond rule-set parity, ruff suffers from the following limitations vis-à-vis F
 | F901 | RaiseNotImplemented | `raise NotImplemented` should be `raise NotImplementedError` |
 | R001 | UselessObjectInheritance | Class `...` inherits from object |
 | R002 | NoAssertEquals | `assertEquals` is deprecated, use `assertEqual` instead |
+| M001 | UnusedNOQA | Unused `noqa` directive |
 
 ## Development
 
@@ -247,29 +298,29 @@ Add this `pyproject.toml` to the CPython directory:
 ```toml
 [tool.ruff]
 line-length = 88
-exclude = [
-    "./resources/test/cpython/Lib/lib2to3/tests/data/bom.py",
-    "./resources/test/cpython/Lib/lib2to3/tests/data/crlf.py",
-    "./resources/test/cpython/Lib/lib2to3/tests/data/different_encoding.py",
-    "./resources/test/cpython/Lib/lib2to3/tests/data/false_encoding.py",
-    "./resources/test/cpython/Lib/lib2to3/tests/data/py2_test_grammar.py",
-    "./resources/test/cpython/Lib/test/bad_coding2.py",
-    "./resources/test/cpython/Lib/test/badsyntax_3131.py",
-    "./resources/test/cpython/Lib/test/badsyntax_pep3120.py",
-    "./resources/test/cpython/Lib/test/encoded_modules/module_iso_8859_1.py",
-    "./resources/test/cpython/Lib/test/encoded_modules/module_koi8_r.py",
-    "./resources/test/cpython/Lib/test/test_fstring.py",
-    "./resources/test/cpython/Lib/test/test_grammar.py",
-    "./resources/test/cpython/Lib/test/test_importlib/test_util.py",
-    "./resources/test/cpython/Lib/test/test_named_expressions.py",
-    "./resources/test/cpython/Lib/test/test_patma.py",
-    "./resources/test/cpython/Lib/test/test_source_encoding.py",
-    "./resources/test/cpython/Tools/c-analyzer/c_parser/parser/_delim.py",
-    "./resources/test/cpython/Tools/i18n/pygettext.py",
-    "./resources/test/cpython/Tools/test2to3/maintest.py",
-    "./resources/test/cpython/Tools/test2to3/setup.py",
-    "./resources/test/cpython/Tools/test2to3/test/test_foo.py",
-    "./resources/test/cpython/Tools/test2to3/test2to3/hello.py",
+extend-exclude = [
+    "Lib/lib2to3/tests/data/bom.py",
+    "Lib/lib2to3/tests/data/crlf.py",
+    "Lib/lib2to3/tests/data/different_encoding.py",
+    "Lib/lib2to3/tests/data/false_encoding.py",
+    "Lib/lib2to3/tests/data/py2_test_grammar.py",
+    "Lib/test/bad_coding2.py",
+    "Lib/test/badsyntax_3131.py",
+    "Lib/test/badsyntax_pep3120.py",
+    "Lib/test/encoded_modules/module_iso_8859_1.py",
+    "Lib/test/encoded_modules/module_koi8_r.py",
+    "Lib/test/test_fstring.py",
+    "Lib/test/test_grammar.py",
+    "Lib/test/test_importlib/test_util.py",
+    "Lib/test/test_named_expressions.py",
+    "Lib/test/test_patma.py",
+    "Lib/test/test_source_encoding.py",
+    "Tools/c-analyzer/c_parser/parser/_delim.py",
+    "Tools/i18n/pygettext.py",
+    "Tools/test2to3/maintest.py",
+    "Tools/test2to3/setup.py",
+    "Tools/test2to3/test/test_foo.py",
+    "Tools/test2to3/test2to3/hello.py",
 ]
 ```
 
@@ -278,17 +329,21 @@ Next, to benchmark the release build:
 ```shell
 cargo build --release
 
-hyperfine --ignore-failure --warmup 1 \
+hyperfine --ignore-failure --warmup 10 --runs 100 \
   "./target/release/ruff ./resources/test/cpython/ --no-cache" \
   "./target/release/ruff ./resources/test/cpython/"
 
 Benchmark 1: ./target/release/ruff ./resources/test/cpython/ --no-cache
-  Time (mean ± σ):     353.6 ms ±   7.6 ms    [User: 2868.8 ms, System: 171.5 ms]
-  Range (min … max):   344.4 ms … 367.3 ms    10 runs
+  Time (mean ± σ):     297.4 ms ±   4.9 ms    [User: 2460.0 ms, System: 67.2 ms]
+  Range (min … max):   287.7 ms … 312.1 ms    100 runs
+
+  Warning: Ignoring non-zero exit code.
 
 Benchmark 2: ./target/release/ruff ./resources/test/cpython/
-  Time (mean ± σ):      59.6 ms ±   2.5 ms    [User: 36.4 ms, System: 345.6 ms]
-  Range (min … max):    55.9 ms …  67.0 ms    48 runs
+  Time (mean ± σ):      79.6 ms ±   7.3 ms    [User: 59.7 ms, System: 356.1 ms]
+  Range (min … max):    62.4 ms … 111.2 ms    100 runs
+
+  Warning: Ignoring non-zero exit code.
 ```
 
 To benchmark against the ecosystem's existing tools:
@@ -300,11 +355,8 @@ hyperfine --ignore-failure --warmup 5 \
   "pyflakes resources/test/cpython" \
   "autoflake --recursive --expand-star-imports --remove-all-unused-imports --remove-unused-variables --remove-duplicate-keys resources/test/cpython" \
   "pycodestyle resources/test/cpython" \
-  "pycodestyle --select E501 resources/test/cpython" \
   "flake8 resources/test/cpython" \
-  "flake8 --select=F831,F541,F634,F403,F706,F901,E501 resources/test/cpython" \
-  "python -m scripts.run_flake8 resources/test/cpython" \
-  "python -m scripts.run_flake8 resources/test/cpython --select=F831,F541,F634,F403,F706,F901,E501"
+  "python -m scripts.run_flake8 resources/test/cpython"
 ```
 
 In order, these evaluate:
@@ -314,66 +366,58 @@ In order, these evaluate:
 - PyFlakes
 - autoflake
 - pycodestyle
-- pycodestyle, limited to the checks supported by ruff
 - Flake8
-- Flake8, limited to the checks supported by ruff
 - Flake8, with a hack to enable multiprocessing on macOS
-- Flake8, with a hack to enable multiprocessing on macOS, limited to the checks supported by ruff
 
 (You can `poetry install` from `./scripts` to create a working environment for the above.)
 
 ```shell
 Benchmark 1: ./target/release/ruff ./resources/test/cpython/ --no-cache
-  Time (mean ± σ):     469.3 ms ±  16.3 ms    [User: 2663.0 ms, System: 972.5 ms]
-  Range (min … max):   445.2 ms … 494.8 ms    10 runs
+  Time (mean ± σ):     297.9 ms ±   7.0 ms    [User: 2436.6 ms, System: 65.9 ms]
+  Range (min … max):   289.9 ms … 314.6 ms    10 runs
+
+  Warning: Ignoring non-zero exit code.
 
 Benchmark 2: pylint --recursive=y resources/test/cpython/
-  Time (mean ± σ):     27.211 s ±  0.097 s    [User: 26.405 s, System: 0.799 s]
-  Range (min … max):   27.056 s … 27.349 s    10 runs
+  Time (mean ± σ):     37.634 s ±  0.225 s    [User: 36.728 s, System: 0.853 s]
+  Range (min … max):   37.201 s … 38.106 s    10 runs
+
+  Warning: Ignoring non-zero exit code.
 
 Benchmark 3: pyflakes resources/test/cpython
-  Time (mean ± σ):     27.309 s ±  0.033 s    [User: 27.137 s, System: 0.169 s]
-  Range (min … max):   27.267 s … 27.372 s    10 runs
+  Time (mean ± σ):     40.950 s ±  0.449 s    [User: 40.688 s, System: 0.229 s]
+  Range (min … max):   40.348 s … 41.671 s    10 runs
+
+  Warning: Ignoring non-zero exit code.
 
 Benchmark 4: autoflake --recursive --expand-star-imports --remove-all-unused-imports --remove-unused-variables --remove-duplicate-keys resources/test/cpython
-  Time (mean ± σ):      8.027 s ±  0.024 s    [User: 74.255 s, System: 0.953 s]
-  Range (min … max):    7.969 s …  8.052 s    10 runs
+  Time (mean ± σ):     11.562 s ±  0.160 s    [User: 107.022 s, System: 1.143 s]
+  Range (min … max):   11.417 s … 11.917 s    10 runs
 
 Benchmark 5: pycodestyle resources/test/cpython
-  Time (mean ± σ):     41.666 s ±  0.266 s    [User: 41.531 s, System: 0.132 s]
-  Range (min … max):   41.295 s … 41.980 s    10 runs
+  Time (mean ± σ):     67.428 s ±  0.985 s    [User: 67.199 s, System: 0.203 s]
+  Range (min … max):   65.313 s … 68.496 s    10 runs
 
-Benchmark 6: pycodestyle --select E501 resources/test/cpython
-  Time (mean ± σ):     14.547 s ±  0.077 s    [User: 14.466 s, System: 0.079 s]
-  Range (min … max):   14.429 s … 14.695 s    10 runs
+  Warning: Ignoring non-zero exit code.
 
-Benchmark 7: flake8 resources/test/cpython
-  Time (mean ± σ):     75.700 s ±  0.152 s    [User: 75.254 s, System: 0.440 s]
-  Range (min … max):   75.513 s … 76.014 s    10 runs
+Benchmark 6: flake8 resources/test/cpython
+  Time (mean ± σ):     116.099 s ±  1.178 s    [User: 115.217 s, System: 0.845 s]
+  Range (min … max):   114.180 s … 117.724 s    10 runs
 
-Benchmark 8: flake8 --select=F831,F541,F634,F403,F706,F901,E501 resources/test/cpython
-  Time (mean ± σ):     75.122 s ±  0.532 s    [User: 74.677 s, System: 0.440 s]
-  Range (min … max):   74.130 s … 75.606 s    10 runs
+  Warning: Ignoring non-zero exit code.
 
-Benchmark 9: python -m scripts.run_flake8 resources/test/cpython
-  Time (mean ± σ):     12.794 s ±  0.147 s    [User: 90.792 s, System: 0.738 s]
-  Range (min … max):   12.606 s … 13.030 s    10 runs
-
-Benchmark 10: python -m scripts.run_flake8 resources/test/cpython --select=F831,F541,F634,F403,F706,F901,E501
-  Time (mean ± σ):     12.487 s ±  0.118 s    [User: 90.052 s, System: 0.714 s]
-  Range (min … max):   12.265 s … 12.665 s    10 runs
+Benchmark 7: python -m scripts.run_flake8 resources/test/cpython
+  Time (mean ± σ):     20.477 s ±  0.349 s    [User: 142.372 s, System: 1.504 s]
+  Range (min … max):   20.107 s … 21.183 s    10 runs
 
 Summary
   './target/release/ruff ./resources/test/cpython/ --no-cache' ran
-   17.10 ± 0.60 times faster than 'autoflake --recursive --expand-star-imports --remove-all-unused-imports --remove-unused-variables --remove-duplicate-keys resources/test/cpython'
-   26.60 ± 0.96 times faster than 'python -m scripts.run_flake8 resources/test/cpython --select=F831,F541,F634,F403,F706,F901,E501'
-   27.26 ± 1.00 times faster than 'python -m scripts.run_flake8 resources/test/cpython'
-   30.99 ± 1.09 times faster than 'pycodestyle --select E501 resources/test/cpython'
-   57.98 ± 2.03 times faster than 'pylint --recursive=y resources/test/cpython/'
-   58.19 ± 2.02 times faster than 'pyflakes resources/test/cpython'
-   88.77 ± 3.14 times faster than 'pycodestyle resources/test/cpython'
-  160.06 ± 5.68 times faster than 'flake8 --select=F831,F541,F634,F403,F706,F901,E501 resources/test/cpython'
-  161.29 ± 5.61 times faster than 'flake8 resources/test/cpython'
+   38.81 ± 1.05 times faster than 'autoflake --recursive --expand-star-imports --remove-all-unused-imports --remove-unused-variables --remove-duplicate-keys resources/test/cpython'
+   68.74 ± 1.99 times faster than 'python -m scripts.run_flake8 resources/test/cpython'
+  126.33 ± 3.05 times faster than 'pylint --recursive=y resources/test/cpython/'
+  137.46 ± 3.55 times faster than 'pyflakes resources/test/cpython'
+  226.35 ± 6.23 times faster than 'pycodestyle resources/test/cpython'
+  389.73 ± 9.92 times faster than 'flake8 resources/test/cpython'
 ```
 
 ## License

examples/print_ast.rs

@@ -2,14 +2,14 @@
 use std::path::PathBuf;
 
 use anyhow::Result;
-use clap::{Parser, ValueHint};
+use clap::Parser;
 use rustpython_parser::parser;
 
 use ruff::fs;
 
 #[derive(Debug, Parser)]
 struct Cli {
-    #[clap(parse(from_os_str), value_hint = ValueHint::FilePath, required = true)]
+    #[arg(required = true)]
     file: PathBuf,
 }
 

examples/print_tokens.rs

@@ -2,14 +2,14 @@
 use std::path::PathBuf;
 
 use anyhow::Result;
-use clap::{Parser, ValueHint};
+use clap::Parser;
 use rustpython_parser::lexer;
 
 use ruff::fs;
 
 #[derive(Debug, Parser)]
 struct Cli {
-    #[clap(parse(from_os_str), value_hint = ValueHint::FilePath, required = true)]
+    #[arg(required = true)]
     file: PathBuf,
 }
 

pyproject.toml

@@ -8,7 +8,6 @@ classifiers = [
     "License :: OSI Approved :: MIT License",
     "Operating System :: OS Independent",
     "Programming Language :: Python",
-    "Programming Language :: Python :: 3.6",
     "Programming Language :: Python :: 3.7",
     "Programming Language :: Python :: 3.8",
     "Programming Language :: Python :: 3.9",

resources/test/fixtures/A001.py

@@ -0,0 +1,27 @@
+import some as sum
+from some import other as int
+
+print = 1
+copyright: 'annotation' = 2
+(complex := 3)
+float = object = 4
+min, max = 5, 6
+
+def bytes():
+    pass
+
+class slice:
+    pass
+
+try:
+    ...
+except ImportError as ValueError:
+    ...
+
+for memoryview, *bytearray in []:
+    pass
+
+with open('file') as str, open('file2') as (all, any):
+    pass
+
+[0 for sum in ()]

resources/test/fixtures/A002.py

@@ -0,0 +1,9 @@
+def func1(str, /, type, *complex, Exception, **getattr):
+    pass
+
+
+async def func2(bytes):
+    pass
+
+
+map([], lambda float: ...)

resources/test/fixtures/A003.py

@@ -0,0 +1,8 @@
+class MyClass:
+    ImportError = 4
+
+    def __init__(self):
+        self.float = 5  # is fine
+
+    def str(self):
+        pass

resources/test/fixtures/E501.py

@@ -5,5 +5,12 @@
 Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
 """
 
+_ = """Lorem ipsum dolor sit amet.
+
+    https://github.com/PyCQA/pycodestyle/pull/258/files#diff-841c622497a8033d10152bfdfb15b20b92437ecdea21a260944ea86b77b51533
+
+Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
+"""  # noqa: E501
+
 _ = "---------------------------------------------------------------------------AAAAAAA"
 _ = "---------------------------------------------------------------------------亜亜亜亜亜亜亜"

resources/test/fixtures/F402.py

@@ -0,0 +1,9 @@
+import os
+import os.path as path
+
+
+for os in range(3):
+    pass
+
+for path in range(3):
+    pass

resources/test/fixtures/F405.py

@@ -0,0 +1,11 @@
+from mymodule import *
+
+
+def print_name():
+    print(name)
+
+
+def print_name(name):
+    print(name)
+
+__all__ = ['a']

resources/test/fixtures/F821.py

@@ -82,3 +82,10 @@ class Ticket:
 def update_tomato():
     print(TOMATO)
     TOMATO = "cherry tomato"
+
+
+A = f'{B}'
+A = (
+    f'B'
+    f'{B}'
+)

resources/test/fixtures/F841.py

@@ -10,13 +10,13 @@ except ValueError as e:
     print(e)
 
 
-def f():
+def f1():
     x = 1
     y = 2
     z = x + y
 
 
-def g():
+def f2():
     foo = (1, 2)
     (a, b) = (1, 2)
 
@@ -26,6 +26,12 @@ def g():
     (x, y) = baz = bar
 
 
-def h():
+def f3():
     locals()
     x = 1
+
+
+def f4():
+    _ = 1
+    __ = 1
+    _discarded = 1

resources/test/fixtures/M001.py

@@ -0,0 +1,57 @@
+def f() -> None:
+    # Valid
+    a = 1  # noqa
+
+    # Valid
+    b = 2  # noqa: F841
+
+    # Invalid
+    c = 1  # noqa
+    print(c)
+
+    # Invalid
+    d = 1  # noqa: E501
+
+    # Invalid
+    d = 1  # noqa: F841, E501
+
+
+# Valid
+_ = """Lorem ipsum dolor sit amet.
+
+    https://github.com/PyCQA/pycodestyle/pull/258/files#diff-841c622497a8033d10152bfdfb15b20b92437ecdea21a260944ea86b77b51533
+
+Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
+"""  # noqa: E501
+
+# Valid
+_ = """Lorem ipsum dolor sit amet.
+
+    https://github.com/PyCQA/pycodestyle/pull/258/files#diff-841c622497a8033d10152bfdfb15b20b92437ecdea21a260944ea86b77b51533
+
+Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
+"""  # noqa
+
+# Invalid
+_ = """Lorem ipsum dolor sit amet.
+
+    https://github.com/PyCQA/pycodestyle/pull/258/files#diff-841c622497a8033d10152bfdfb15b20b92437ecdea21a260944ea86b77b51533
+
+Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
+"""  # noqa: E501, F841
+
+# Invalid
+_ = """Lorem ipsum dolor sit amet.
+
+    https://github.com/PyCQA/pycodestyle/pull/258/files#diff-841c622497a8033d10152bfdfb15b20b92437ecdea21a260944ea86b77b51533
+
+Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor.
+"""  # noqa: E501
+
+# Invalid
+_ = """Lorem ipsum dolor sit amet.
+
+    https://github.com/PyCQA/pycodestyle/pull/258/files#diff-841c622497a8033d10152bfdfb15b20b92437ecdea21a260944ea86b77b51533
+
+Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor.
+"""  # noqa

src/ast/checks.rs

@@ -1,15 +1,17 @@
 use std::collections::BTreeSet;
 
 use itertools::izip;
+use regex::Regex;
 use rustpython_parser::ast::{
     Arg, Arguments, Cmpop, Constant, Excepthandler, ExcepthandlerKind, Expr, ExprKind, Keyword,
     Location, Stmt, StmtKind, Unaryop,
 };
 
 use crate::ast::operations::SourceCodeLocator;
-use crate::ast::types::{Binding, BindingKind, FunctionScope, Scope, ScopeKind};
+use crate::ast::types::{Binding, BindingKind, CheckLocator, FunctionScope, Scope, ScopeKind};
 use crate::autofix::{fixer, fixes};
 use crate::checks::{Check, CheckKind, Fix, RejectedCmpop};
+use crate::python::builtins::BUILTINS;
 
 /// Check IfTuple compliance.
 pub fn check_if_tuple(test: &Expr, location: Location) -> Option<Check> {
@@ -37,6 +39,7 @@ pub fn check_not_tests(
     operand: &Expr,
     check_not_in: bool,
     check_not_is: bool,
+    locator: &dyn CheckLocator,
 ) -> Vec<Check> {
     let mut checks: Vec<Check> = vec![];
 
@@ -46,12 +49,18 @@ pub fn check_not_tests(
                 match op {
                     Cmpop::In => {
                         if check_not_in {
-                            checks.push(Check::new(CheckKind::NotInTest, operand.location));
+                            checks.push(Check::new(
+                                CheckKind::NotInTest,
+                                locator.locate_check(operand.location),
+                            ));
                         }
                     }
                     Cmpop::Is => {
                         if check_not_is {
-                            checks.push(Check::new(CheckKind::NotIsTest, operand.location));
+                            checks.push(Check::new(
+                                CheckKind::NotIsTest,
+                                locator.locate_check(operand.location),
+                            ));
                         }
                     }
                     _ => {}
@@ -64,7 +73,11 @@ pub fn check_not_tests(
 }
 
 /// Check UnusedVariable compliance.
-pub fn check_unused_variables(scope: &Scope) -> Vec<Check> {
+pub fn check_unused_variables(
+    scope: &Scope,
+    locator: &dyn CheckLocator,
+    dummy_variable_rgx: &Regex,
+) -> Vec<Check> {
     let mut checks: Vec<Check> = vec![];
 
     if matches!(
@@ -75,17 +88,16 @@ pub fn check_unused_variables(scope: &Scope) -> Vec<Check> {
     }
 
     for (name, binding) in scope.values.iter() {
-        // TODO(charlie): Ignore if using `locals`.
         if binding.used.is_none()
-            && name != "_"
+            && matches!(binding.kind, BindingKind::Assignment)
+            && !dummy_variable_rgx.is_match(name)
             && name != "__tracebackhide__"
             && name != "__traceback_info__"
             && name != "__traceback_supplement__"
-            && matches!(binding.kind, BindingKind::Assignment)
         {
             checks.push(Check::new(
                 CheckKind::UnusedVariable(name.to_string()),
-                binding.location,
+                locator.locate_check(binding.location),
             ));
         }
     }
@@ -299,6 +311,7 @@ pub fn check_repeated_keys(
     keys: &Vec<Expr>,
     check_repeated_literals: bool,
     check_repeated_variables: bool,
+    locator: &dyn CheckLocator,
 ) -> Vec<Check> {
     let mut checks: Vec<Check> = vec![];
 
@@ -313,7 +326,7 @@ pub fn check_repeated_keys(
                     if check_repeated_literals && v1 == v2 {
                         checks.push(Check::new(
                             CheckKind::MultiValueRepeatedKeyLiteral,
-                            k2.location,
+                            locator.locate_check(k2.location),
                         ))
                     }
                 }
@@ -321,7 +334,7 @@ pub fn check_repeated_keys(
                     if check_repeated_variables && v1 == v2 {
                         checks.push(Check::new(
                             CheckKind::MultiValueRepeatedKeyVariable((*v2).to_string()),
-                            k2.location,
+                            locator.locate_check(k2.location),
                         ))
                     }
                 }
@@ -340,6 +353,7 @@ pub fn check_literal_comparisons(
     comparators: &Vec<Expr>,
     check_none_comparisons: bool,
     check_true_false_comparisons: bool,
+    locator: &dyn CheckLocator,
 ) -> Vec<Check> {
     let mut checks: Vec<Check> = vec![];
 
@@ -359,13 +373,13 @@ pub fn check_literal_comparisons(
         if matches!(op, Cmpop::Eq) {
             checks.push(Check::new(
                 CheckKind::NoneComparison(RejectedCmpop::Eq),
-                comparator.location,
+                locator.locate_check(comparator.location),
             ));
         }
         if matches!(op, Cmpop::NotEq) {
             checks.push(Check::new(
                 CheckKind::NoneComparison(RejectedCmpop::NotEq),
-                comparator.location,
+                locator.locate_check(comparator.location),
             ));
         }
     }
@@ -379,13 +393,13 @@ pub fn check_literal_comparisons(
             if matches!(op, Cmpop::Eq) {
                 checks.push(Check::new(
                     CheckKind::TrueFalseComparison(value, RejectedCmpop::Eq),
-                    comparator.location,
+                    locator.locate_check(comparator.location),
                 ));
             }
             if matches!(op, Cmpop::NotEq) {
                 checks.push(Check::new(
                     CheckKind::TrueFalseComparison(value, RejectedCmpop::NotEq),
-                    comparator.location,
+                    locator.locate_check(comparator.location),
                 ));
             }
         }
@@ -405,13 +419,13 @@ pub fn check_literal_comparisons(
             if matches!(op, Cmpop::Eq) {
                 checks.push(Check::new(
                     CheckKind::NoneComparison(RejectedCmpop::Eq),
-                    comparator.location,
+                    locator.locate_check(comparator.location),
                 ));
             }
             if matches!(op, Cmpop::NotEq) {
                 checks.push(Check::new(
                     CheckKind::NoneComparison(RejectedCmpop::NotEq),
-                    comparator.location,
+                    locator.locate_check(comparator.location),
                 ));
             }
         }
@@ -425,13 +439,13 @@ pub fn check_literal_comparisons(
                 if matches!(op, Cmpop::Eq) {
                     checks.push(Check::new(
                         CheckKind::TrueFalseComparison(value, RejectedCmpop::Eq),
-                        comparator.location,
+                        locator.locate_check(comparator.location),
                     ));
                 }
                 if matches!(op, Cmpop::NotEq) {
                     checks.push(Check::new(
                         CheckKind::TrueFalseComparison(value, RejectedCmpop::NotEq),
-                        comparator.location,
+                        locator.locate_check(comparator.location),
                     ));
                 }
             }
@@ -528,9 +542,9 @@ pub fn check_type_comparison(
 /// Check TwoStarredExpressions and TooManyExpressionsInStarredAssignment compliance.
 pub fn check_starred_expressions(
     elts: &[Expr],
-    location: Location,
     check_too_many_expressions: bool,
     check_two_starred_expressions: bool,
+    location: Location,
 ) -> Option<Check> {
     let mut has_starred: bool = false;
     let mut starred_index: Option<usize> = None;
@@ -563,6 +577,7 @@ pub fn check_break_outside_loop(
     stmt: &Stmt,
     parents: &[&Stmt],
     parent_stack: &[usize],
+    locator: &dyn CheckLocator,
 ) -> Option<Check> {
     let mut allowed: bool = false;
     let mut parent = stmt;
@@ -589,7 +604,10 @@ pub fn check_break_outside_loop(
     }
 
     if !allowed {
-        Some(Check::new(CheckKind::BreakOutsideLoop, stmt.location))
+        Some(Check::new(
+            CheckKind::BreakOutsideLoop,
+            locator.locate_check(stmt.location),
+        ))
     } else {
         None
     }
@@ -600,6 +618,7 @@ pub fn check_continue_outside_loop(
     stmt: &Stmt,
     parents: &[&Stmt],
     parent_stack: &[usize],
+    locator: &dyn CheckLocator,
 ) -> Option<Check> {
     let mut allowed: bool = false;
     let mut parent = stmt;
@@ -626,7 +645,37 @@ pub fn check_continue_outside_loop(
     }
 
     if !allowed {
-        Some(Check::new(CheckKind::ContinueOutsideLoop, stmt.location))
+        Some(Check::new(
+            CheckKind::ContinueOutsideLoop,
+            locator.locate_check(stmt.location),
+        ))
+    } else {
+        None
+    }
+}
+
+// flake8-builtins
+pub enum ShadowingType {
+    Variable,
+    Argument,
+    Attribute,
+}
+
+/// Check builtin name shadowing
+pub fn check_builtin_shadowing(
+    name: &str,
+    location: Location,
+    node_type: ShadowingType,
+) -> Option<Check> {
+    if BUILTINS.contains(&name) {
+        Some(Check::new(
+            match node_type {
+                ShadowingType::Variable => CheckKind::BuiltinVariableShadowing(name.to_string()),
+                ShadowingType::Argument => CheckKind::BuiltinArgumentShadowing(name.to_string()),
+                ShadowingType::Attribute => CheckKind::BuiltinAttributeShadowing(name.to_string()),
+            },
+            location,
+        ))
     } else {
         None
     }

src/ast/types.rs

@@ -25,6 +25,7 @@ pub enum ScopeKind {
 pub struct Scope {
     pub id: usize,
     pub kind: ScopeKind,
+    pub import_starred: bool,
     pub values: BTreeMap<String, Binding>,
 }
 
@@ -33,6 +34,7 @@ impl Scope {
         Scope {
             id: id(),
             kind,
+            import_starred: false,
             values: BTreeMap::new(),
         }
     }
@@ -44,6 +46,7 @@ pub enum BindingKind {
     Argument,
     Assignment,
     Binding,
+    LoopVar,
     Builtin,
     ClassDefinition,
     Definition,
@@ -62,3 +65,7 @@ pub struct Binding {
     /// last used.
     pub used: Option<(usize, Location)>,
 }
+
+pub trait CheckLocator {
+    fn locate_check(&self, default: Location) -> Location;
+}

src/check_ast.rs

@@ -9,7 +9,7 @@ use rustpython_parser::parser;
 
 use crate::ast::operations::{extract_all_names, SourceCodeLocator};
 use crate::ast::relocate::relocate_expr;
-use crate::ast::types::{Binding, BindingKind, FunctionScope, Scope, ScopeKind};
+use crate::ast::types::{Binding, BindingKind, CheckLocator, FunctionScope, Scope, ScopeKind};
 use crate::ast::visitor::{walk_excepthandler, Visitor};
 use crate::ast::{checks, operations, visitor};
 use crate::autofix::fixer;
@@ -42,7 +42,7 @@ struct Checker<'a> {
     deferred_lambdas: Vec<(&'a Expr, Vec<usize>, Vec<usize>)>,
     deferred_assignments: Vec<usize>,
     // Derivative state.
-    in_f_string: bool,
+    in_f_string: Option<Location>,
     in_annotation: bool,
     in_literal: bool,
     seen_non_import: bool,
@@ -74,7 +74,7 @@ impl<'a> Checker<'a> {
             deferred_functions: vec![],
             deferred_lambdas: vec![],
             deferred_assignments: vec![],
-            in_f_string: false,
+            in_f_string: None,
             in_annotation: false,
             in_literal: false,
             seen_non_import: false,
@@ -171,7 +171,6 @@ where
         // Pre-visit.
         match &stmt.node {
             StmtKind::Global { names } | StmtKind::Nonlocal { names } => {
-                // TODO(charlie): Handle doctests.
                 let global_scope_id = self.scopes[GLOBAL_SCOPE_INDEX].id;
 
                 let current_scope =
@@ -193,25 +192,34 @@ where
                 }
 
                 if self.settings.select.contains(&CheckCode::E741) {
-                    self.checks.extend(names.iter().filter_map(|name| {
-                        checks::check_ambiguous_variable_name(name, stmt.location)
-                    }));
+                    let location = self.locate_check(stmt.location);
+                    self.checks.extend(
+                        names.iter().filter_map(|name| {
+                            checks::check_ambiguous_variable_name(name, location)
+                        }),
+                    );
                 }
             }
             StmtKind::Break => {
                 if self.settings.select.contains(&CheckCode::F701) {
-                    if let Some(check) =
-                        checks::check_break_outside_loop(stmt, &self.parents, &self.parent_stack)
-                    {
+                    if let Some(check) = checks::check_break_outside_loop(
+                        stmt,
+                        &self.parents,
+                        &self.parent_stack,
+                        self,
+                    ) {
                         self.checks.push(check);
                     }
                 }
             }
             StmtKind::Continue => {
                 if self.settings.select.contains(&CheckCode::F702) {
-                    if let Some(check) =
-                        checks::check_continue_outside_loop(stmt, &self.parents, &self.parent_stack)
-                    {
+                    if let Some(check) = checks::check_continue_outside_loop(
+                        stmt,
+                        &self.parents,
+                        &self.parent_stack,
+                        self,
+                    ) {
                         self.checks.push(check);
                     }
                 }
@@ -231,11 +239,16 @@ where
                 ..
             } => {
                 if self.settings.select.contains(&CheckCode::E743) {
-                    if let Some(check) = checks::check_ambiguous_function_name(name, stmt.location)
-                    {
+                    if let Some(check) = checks::check_ambiguous_function_name(
+                        name,
+                        self.locate_check(stmt.location),
+                    ) {
                         self.checks.push(check);
                     }
                 }
+
+                self.check_builtin_shadowing(name, stmt.location, true);
+
                 for expr in decorator_list {
                     self.visit_expr(expr);
                 }
@@ -293,7 +306,7 @@ where
                             ScopeKind::Class | ScopeKind::Module => {
                                 self.checks.push(Check::new(
                                     CheckKind::ReturnOutsideFunction,
-                                    stmt.location,
+                                    self.locate_check(stmt.location),
                                 ));
                             }
                             _ => {}
@@ -325,11 +338,15 @@ where
                 }
 
                 if self.settings.select.contains(&CheckCode::E742) {
-                    if let Some(check) = checks::check_ambiguous_class_name(name, stmt.location) {
+                    if let Some(check) =
+                        checks::check_ambiguous_class_name(name, self.locate_check(stmt.location))
+                    {
                         self.checks.push(check);
                     }
                 }
 
+                self.check_builtin_shadowing(name, self.locate_check(stmt.location), false);
+
                 for expr in bases {
                     self.visit_expr(expr)
                 }
@@ -351,7 +368,7 @@ where
                 {
                     self.checks.push(Check::new(
                         CheckKind::ModuleImportNotAtTopOfFile,
-                        stmt.location,
+                        self.locate_check(stmt.location),
                     ));
                 }
 
@@ -370,6 +387,10 @@ where
                             },
                         )
                     } else {
+                        if let Some(asname) = &alias.node.asname {
+                            self.check_builtin_shadowing(asname, stmt.location, false);
+                        }
+
                         self.add_binding(
                             alias
                                 .node
@@ -391,7 +412,11 @@ where
                     }
                 }
             }
-            StmtKind::ImportFrom { names, module, .. } => {
+            StmtKind::ImportFrom {
+                names,
+                module,
+                level,
+            } => {
                 if self
                     .settings
                     .select
@@ -401,7 +426,7 @@ where
                 {
                     self.checks.push(Check::new(
                         CheckKind::ModuleImportNotAtTopOfFile,
-                        stmt.location,
+                        self.locate_check(stmt.location),
                     ));
                 }
 
@@ -437,18 +462,26 @@ where
                         {
                             self.checks.push(Check::new(
                                 CheckKind::FutureFeatureNotDefined(alias.node.name.to_string()),
-                                stmt.location,
+                                self.locate_check(stmt.location),
                             ));
                         }
 
                         if self.settings.select.contains(&CheckCode::F404) && !self.futures_allowed
                         {
-                            self.checks
-                                .push(Check::new(CheckKind::LateFutureImport, stmt.location));
+                            self.checks.push(Check::new(
+                                CheckKind::LateFutureImport,
+                                self.locate_check(stmt.location),
+                            ));
                         }
                     } else if alias.node.name == "*" {
+                        let module_name = format!(
+                            "{}{}",
+                            ".".repeat(level.unwrap_or_default()),
+                            module.clone().unwrap_or_else(|| "module".to_string()),
+                        );
+
                         self.add_binding(
-                            name,
+                            module_name.to_string(),
                             Binding {
                                 kind: BindingKind::StarImportation,
                                 used: None,
@@ -456,28 +489,34 @@ where
                             },
                         );
 
-                        if self.settings.select.contains(&CheckCode::F403) {
-                            self.checks.push(Check::new(
-                                CheckKind::ImportStarUsage(
-                                    module.clone().unwrap_or_else(|| "module".to_string()),
-                                ),
-                                stmt.location,
-                            ));
-                        }
-
                         if self.settings.select.contains(&CheckCode::F406) {
                             let scope = &self.scopes
                                 [*(self.scope_stack.last().expect("No current scope found."))];
                             if !matches!(scope.kind, ScopeKind::Module) {
                                 self.checks.push(Check::new(
-                                    CheckKind::ImportStarNotPermitted(
-                                        module.clone().unwrap_or_else(|| "module".to_string()),
-                                    ),
-                                    stmt.location,
+                                    CheckKind::ImportStarNotPermitted(module_name.to_string()),
+                                    self.locate_check(stmt.location),
                                 ));
                             }
                         }
+
+                        if self.settings.select.contains(&CheckCode::F403) {
+                            self.checks.push(Check::new(
+                                CheckKind::ImportStarUsed(module_name.to_string()),
+                                self.locate_check(stmt.location),
+                            ));
+                        }
+
+                        let scope = &mut self.scopes[*(self
+                            .scope_stack
+                            .last_mut()
+                            .expect("No current scope found."))];
+                        scope.import_starred = true;
                     } else {
+                        if let Some(asname) = &alias.node.asname {
+                            self.check_builtin_shadowing(asname, stmt.location, false);
+                        }
+
                         let binding = Binding {
                             kind: BindingKind::Importation(match module {
                                 None => name.clone(),
@@ -504,14 +543,18 @@ where
             }
             StmtKind::If { test, .. } => {
                 if self.settings.select.contains(&CheckCode::F634) {
-                    if let Some(check) = checks::check_if_tuple(test, stmt.location) {
+                    if let Some(check) =
+                        checks::check_if_tuple(test, self.locate_check(stmt.location))
+                    {
                         self.checks.push(check);
                     }
                 }
             }
             StmtKind::Assert { test, .. } => {
                 if self.settings.select.contains(CheckKind::AssertTuple.code()) {
-                    if let Some(check) = checks::check_assert_tuple(test, stmt.location) {
+                    if let Some(check) =
+                        checks::check_assert_tuple(test, self.locate_check(stmt.location))
+                    {
                         self.checks.push(check);
                     }
                 }
@@ -525,7 +568,9 @@ where
             }
             StmtKind::Assign { value, .. } => {
                 if self.settings.select.contains(&CheckCode::E731) {
-                    if let Some(check) = checks::check_do_not_assign_lambda(value, stmt.location) {
+                    if let Some(check) =
+                        checks::check_do_not_assign_lambda(value, self.locate_check(stmt.location))
+                    {
                         self.checks.push(check);
                     }
                 }
@@ -533,9 +578,10 @@ where
             StmtKind::AnnAssign { value, .. } => {
                 if self.settings.select.contains(&CheckCode::E731) {
                     if let Some(value) = value {
-                        if let Some(check) =
-                            checks::check_do_not_assign_lambda(value, stmt.location)
-                        {
+                        if let Some(check) = checks::check_do_not_assign_lambda(
+                            value,
+                            self.locate_check(stmt.location),
+                        ) {
                             self.checks.push(check);
                         }
                     }
@@ -590,7 +636,6 @@ where
         let prev_in_literal = self.in_literal;
         let prev_in_annotation = self.in_annotation;
 
-        // Important:
         if self.in_annotation && self.annotations_future_enabled {
             self.deferred_annotations.push((
                 expr,
@@ -616,9 +661,9 @@ where
                         self.settings.select.contains(&CheckCode::F622);
                     if let Some(check) = checks::check_starred_expressions(
                         elts,
-                        expr.location,
                         check_too_many_expressions,
                         check_two_starred_expressions,
+                        self.locate_check(expr.location),
                     ) {
                         self.checks.push(check);
                     }
@@ -628,12 +673,16 @@ where
                 ExprContext::Load => self.handle_node_load(expr),
                 ExprContext::Store => {
                     if self.settings.select.contains(&CheckCode::E741) {
-                        if let Some(check) =
-                            checks::check_ambiguous_variable_name(id, expr.location)
-                        {
+                        if let Some(check) = checks::check_ambiguous_variable_name(
+                            id,
+                            self.locate_check(expr.location),
+                        ) {
                             self.checks.push(check);
                         }
                     }
+
+                    self.check_builtin_shadowing(id, expr.location, true);
+
                     let parent =
                         self.parents[*(self.parent_stack.last().expect("No parent found."))];
                     self.handle_node_store(expr, parent);
@@ -661,18 +710,6 @@ where
                         }
                     }
                 }
-
-                //
-                // if id == "locals" {
-                //     let scope = &self.scopes
-                //         [*(self.scope_stack.last().expect("No current scope found."))];
-                //     if matches!(scope.kind, ScopeKind::Function(_)) {
-                //     let parent =
-                //         self.parents[*(self.parent_stack.last().expect("No parent found."))];
-                //         if matches!(parent.node, StmtKind::Call)
-                //     }
-                //
-                // }
             }
             ExprKind::Dict { keys, .. } => {
                 let check_repeated_literals = self.settings.select.contains(&CheckCode::F601);
@@ -682,6 +719,7 @@ where
                         keys,
                         check_repeated_literals,
                         check_repeated_variables,
+                        self,
                     ));
                 }
             }
@@ -694,12 +732,14 @@ where
                     .contains(CheckKind::YieldOutsideFunction.code())
                     && matches!(scope.kind, ScopeKind::Class | ScopeKind::Module)
                 {
-                    self.checks
-                        .push(Check::new(CheckKind::YieldOutsideFunction, expr.location));
+                    self.checks.push(Check::new(
+                        CheckKind::YieldOutsideFunction,
+                        self.locate_check(expr.location),
+                    ));
                 }
             }
             ExprKind::JoinedStr { values } => {
-                if !self.in_f_string
+                if self.in_f_string.is_none()
                     && self
                         .settings
                         .select
@@ -710,10 +750,10 @@ where
                 {
                     self.checks.push(Check::new(
                         CheckKind::FStringMissingPlaceholders,
-                        expr.location,
+                        self.locate_check(expr.location),
                     ));
                 }
-                self.in_f_string = true;
+                self.in_f_string = Some(expr.location);
             }
             ExprKind::BinOp {
                 left,
@@ -746,6 +786,7 @@ where
                         operand,
                         check_not_in,
                         check_not_is,
+                        self,
                     ));
                 }
             }
@@ -763,6 +804,7 @@ where
                         comparators,
                         check_none_comparisons,
                         check_true_false_comparisons,
+                        self,
                     ));
                 }
 
@@ -771,7 +813,7 @@ where
                         left,
                         ops,
                         comparators,
-                        expr.location,
+                        self.locate_check(expr.location),
                     ));
                 }
 
@@ -779,7 +821,7 @@ where
                     self.checks.extend(checks::check_type_comparison(
                         ops,
                         comparators,
-                        expr.location,
+                        self.locate_check(expr.location),
                     ));
                 }
             }
@@ -944,12 +986,16 @@ where
                 match name {
                     Some(name) => {
                         if self.settings.select.contains(&CheckCode::E741) {
-                            if let Some(check) =
-                                checks::check_ambiguous_variable_name(name, excepthandler.location)
-                            {
+                            if let Some(check) = checks::check_ambiguous_variable_name(
+                                name,
+                                self.locate_check(excepthandler.location),
+                            ) {
                                 self.checks.push(check);
                             }
                         }
+
+                        self.check_builtin_shadowing(name, excepthandler.location, false);
+
                         let scope = &self.scopes
                             [*(self.scope_stack.last().expect("No current scope found."))];
                         if scope.values.contains_key(name) {
@@ -1046,11 +1092,21 @@ where
         );
 
         if self.settings.select.contains(&CheckCode::E741) {
-            if let Some(check) = checks::check_ambiguous_variable_name(&arg.node.arg, arg.location)
-            {
+            if let Some(check) = checks::check_ambiguous_variable_name(
+                &arg.node.arg,
+                self.locate_check(arg.location),
+            ) {
                 self.checks.push(check);
             }
         }
+
+        self.check_builtin_arg_shadowing(&arg.node.arg, arg.location);
+    }
+}
+
+impl CheckLocator for Checker<'_> {
+    fn locate_check(&self, default: Location) -> Location {
+        self.in_f_string.unwrap_or(default)
     }
 }
 
@@ -1110,12 +1166,24 @@ impl<'a> Checker<'a> {
         // TODO(charlie): Don't treat annotations as assignments if there is an existing value.
         let binding = match scope.values.get(&name) {
             None => binding,
-            Some(existing) => Binding {
-                kind: binding.kind,
-                location: binding.location,
-                used: existing.used,
-            },
+            Some(existing) => {
+                if self.settings.select.contains(&CheckCode::F402)
+                    && matches!(existing.kind, BindingKind::Importation(_))
+                    && matches!(binding.kind, BindingKind::LoopVar)
+                {
+                    self.checks.push(Check::new(
+                        CheckKind::ImportShadowedByLoopVar(name.clone(), existing.location.row()),
+                        binding.location,
+                    ));
+                }
+                Binding {
+                    kind: binding.kind,
+                    location: binding.location,
+                    used: existing.used,
+                }
+            }
         };
+
         scope.values.insert(name, binding);
     }
 
@@ -1126,6 +1194,7 @@ impl<'a> Checker<'a> {
 
             let mut first_iter = true;
             let mut in_generator = false;
+            let mut import_starred = false;
             for scope_index in self.scope_stack.iter().rev() {
                 let scope = &mut self.scopes[*scope_index];
                 if matches!(scope.kind, ScopeKind::Class) {
@@ -1142,6 +1211,28 @@ impl<'a> Checker<'a> {
 
                 first_iter = false;
                 in_generator = matches!(scope.kind, ScopeKind::Generator);
+                import_starred = import_starred || scope.import_starred;
+            }
+
+            if import_starred {
+                if self.settings.select.contains(&CheckCode::F405) {
+                    let mut from_list = vec![];
+                    for scope_index in self.scope_stack.iter().rev() {
+                        let scope = &self.scopes[*scope_index];
+                        for (name, binding) in scope.values.iter() {
+                            if matches!(binding.kind, BindingKind::StarImportation) {
+                                from_list.push(name.as_str());
+                            }
+                        }
+                    }
+                    from_list.sort();
+
+                    self.checks.push(Check::new(
+                        CheckKind::ImportStarUsage(id.clone(), from_list.join(", ")),
+                        self.locate_check(expr.location),
+                    ));
+                }
+                return;
             }
 
             if self.settings.select.contains(&CheckCode::F821) {
@@ -1151,7 +1242,7 @@ impl<'a> Checker<'a> {
                 }
                 self.checks.push(Check::new(
                     CheckKind::UndefinedName(id.clone()),
-                    expr.location,
+                    self.locate_check(expr.location),
                 ))
             }
         }
@@ -1173,7 +1264,7 @@ impl<'a> Checker<'a> {
                                 if scope_id == current.id {
                                     self.checks.push(Check::new(
                                         CheckKind::UndefinedLocal(id.clone()),
-                                        location,
+                                        self.locate_check(location),
                                     ));
                                 }
                             }
@@ -1198,8 +1289,19 @@ impl<'a> Checker<'a> {
             if matches!(
                 parent.node,
                 StmtKind::For { .. } | StmtKind::AsyncFor { .. }
-            ) || operations::is_unpacking_assignment(parent)
-            {
+            ) {
+                self.add_binding(
+                    id.to_string(),
+                    Binding {
+                        kind: BindingKind::LoopVar,
+                        used: None,
+                        location: expr.location,
+                    },
+                );
+                return;
+            }
+
+            if operations::is_unpacking_assignment(parent) {
                 self.add_binding(
                     id.to_string(),
                     Binding {
@@ -1255,7 +1357,7 @@ impl<'a> Checker<'a> {
             {
                 self.checks.push(Check::new(
                     CheckKind::UndefinedName(id.clone()),
-                    expr.location,
+                    self.locate_check(expr.location),
                 ))
             }
         }
@@ -1280,7 +1382,7 @@ impl<'a> Checker<'a> {
             } else if self.settings.select.contains(&CheckCode::F722) {
                 self.checks.push(Check::new(
                     CheckKind::ForwardAnnotationSyntaxError(expression.to_string()),
-                    location,
+                    self.locate_check(location),
                 ));
             }
         }
@@ -1332,17 +1434,21 @@ impl<'a> Checker<'a> {
     }
 
     fn check_deferred_assignments(&mut self) {
-        while let Some(index) = self.deferred_assignments.pop() {
-            if self.settings.select.contains(&CheckCode::F841) {
-                self.checks
-                    .extend(checks::check_unused_variables(&self.scopes[index]));
+        if self.settings.select.contains(&CheckCode::F841) {
+            while let Some(index) = self.deferred_assignments.pop() {
+                self.checks.extend(checks::check_unused_variables(
+                    &self.scopes[index],
+                    self,
+                    &self.settings.dummy_variable_rgx,
+                ));
             }
         }
     }
 
     fn check_dead_scopes(&mut self) {
-        if !self.settings.select.contains(&CheckCode::F822)
-            && !self.settings.select.contains(&CheckCode::F401)
+        if !self.settings.select.contains(&CheckCode::F401)
+            && !self.settings.select.contains(&CheckCode::F405)
+            && !self.settings.select.contains(&CheckCode::F822)
         {
             return;
         }
@@ -1357,15 +1463,39 @@ impl<'a> Checker<'a> {
             });
 
             if self.settings.select.contains(&CheckCode::F822)
+                && !scope.import_starred
                 && !self.path.ends_with("__init__.py")
             {
-                if let Some(binding) = all_binding {
+                if let Some(all_binding) = all_binding {
                     if let Some(names) = all_names {
                         for name in names {
                             if !scope.values.contains_key(name) {
                                 self.checks.push(Check::new(
                                     CheckKind::UndefinedExport(name.to_string()),
-                                    binding.location,
+                                    self.locate_check(all_binding.location),
+                                ));
+                            }
+                        }
+                    }
+                }
+            }
+
+            if self.settings.select.contains(&CheckCode::F405) && scope.import_starred {
+                if let Some(all_binding) = all_binding {
+                    if let Some(names) = all_names {
+                        let mut from_list = vec![];
+                        for (name, binding) in scope.values.iter() {
+                            if matches!(binding.kind, BindingKind::StarImportation) {
+                                from_list.push(name.as_str());
+                            }
+                        }
+                        from_list.sort();
+
+                        for name in names {
+                            if !scope.values.contains_key(name) {
+                                self.checks.push(Check::new(
+                                    CheckKind::ImportStarUsage(name.clone(), from_list.join(", ")),
+                                    self.locate_check(all_binding.location),
                                 ));
                             }
                         }
@@ -1386,7 +1516,7 @@ impl<'a> Checker<'a> {
                             | BindingKind::SubmoduleImportation(full_name) => {
                                 self.checks.push(Check::new(
                                     CheckKind::UnusedImport(full_name.to_string()),
-                                    binding.location,
+                                    self.locate_check(binding.location),
                                 ));
                             }
                             _ => {}
@@ -1396,6 +1526,44 @@ impl<'a> Checker<'a> {
             }
         }
     }
+
+    fn check_builtin_shadowing(&mut self, name: &str, location: Location, is_attribute: bool) {
+        let scope = &self.scopes[*(self.scope_stack.last().expect("No current scope found."))];
+
+        // flake8-builtins
+        if is_attribute
+            && matches!(scope.kind, ScopeKind::Class)
+            && self.settings.select.contains(&CheckCode::A003)
+        {
+            if let Some(check) = checks::check_builtin_shadowing(
+                name,
+                self.locate_check(location),
+                checks::ShadowingType::Attribute,
+            ) {
+                self.checks.push(check);
+            }
+        } else if self.settings.select.contains(&CheckCode::A001) {
+            if let Some(check) = checks::check_builtin_shadowing(
+                name,
+                self.locate_check(location),
+                checks::ShadowingType::Variable,
+            ) {
+                self.checks.push(check);
+            }
+        }
+    }
+
+    fn check_builtin_arg_shadowing(&mut self, name: &str, location: Location) {
+        if self.settings.select.contains(&CheckCode::A002) {
+            if let Some(check) = checks::check_builtin_shadowing(
+                name,
+                self.locate_check(location),
+                checks::ShadowingType::Argument,
+            ) {
+                self.checks.push(check);
+            }
+        }
+    }
 }
 
 pub fn check_ast(

src/check_lines.rs

@@ -1,6 +1,11 @@
+use std::collections::BTreeMap;
+
 use rustpython_parser::ast::Location;
 
-use crate::checks::{Check, CheckCode, CheckKind};
+use crate::autofix::fixer;
+use crate::checks::{Check, CheckCode, CheckKind, Fix};
+use crate::noqa;
+use crate::noqa::Directive;
 use crate::settings::Settings;
 
 /// Whether the given line is too long and should be reported.
@@ -19,17 +24,58 @@ fn should_enforce_line_length(line: &str, length: usize, limit: usize) -> bool {
     }
 }
 
-pub fn check_lines(checks: &mut Vec<Check>, contents: &str, settings: &Settings) {
+pub fn check_lines(
+    checks: &mut Vec<Check>,
+    contents: &str,
+    noqa_line_for: &[usize],
+    settings: &Settings,
+    autofix: &fixer::Mode,
+) {
     let enforce_line_too_long = settings.select.contains(&CheckCode::E501);
+    let enforce_noqa = settings.select.contains(&CheckCode::M001);
+
+    let mut noqa_directives: BTreeMap<usize, (Directive, Vec<&str>)> = BTreeMap::new();
 
     let mut line_checks = vec![];
     let mut ignored = vec![];
-    for (row, line) in contents.lines().enumerate() {
+
+    let lines: Vec<&str> = contents.lines().collect();
+    for (lineno, line) in lines.iter().enumerate() {
+        // 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)
+            .map(|lineno| lineno - 1)
+            .unwrap_or(lineno);
+
+        if enforce_noqa {
+            noqa_directives
+                .entry(noqa_lineno)
+                .or_insert_with(|| (noqa::extract_noqa_directive(lines[noqa_lineno]), vec![]));
+        }
+
         // Remove any ignored checks.
         // TODO(charlie): Only validate checks for the current line.
         for (index, check) in checks.iter().enumerate() {
-            if check.location.row() == row + 1 && check.is_inline_ignored(line) {
-                ignored.push(index);
+            if 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_str());
+                        ignored.push(index)
+                    }
+                    (Directive::Codes(_, codes), matches) => {
+                        if codes.contains(&check.kind.code().as_str()) {
+                            matches.push(check.kind.code().as_str());
+                            ignored.push(index);
+                        }
+                    }
+                    (Directive::None, _) => {}
+                }
             }
         }
 
@@ -37,16 +83,94 @@ pub fn check_lines(checks: &mut Vec<Check>, contents: &str, settings: &Settings)
         if enforce_line_too_long {
             let line_length = line.chars().count();
             if should_enforce_line_length(line, line_length, settings.line_length) {
+                let noqa = noqa_directives
+                    .entry(noqa_lineno)
+                    .or_insert_with(|| (noqa::extract_noqa_directive(lines[noqa_lineno]), vec![]));
+
                 let check = Check::new(
                     CheckKind::LineTooLong(line_length, settings.line_length),
-                    Location::new(row + 1, settings.line_length + 1),
+                    Location::new(lineno + 1, settings.line_length + 1),
                 );
-                if !check.is_inline_ignored(line) {
-                    line_checks.push(check);
+
+                match noqa {
+                    (Directive::All(_), matches) => {
+                        matches.push(check.kind.code().as_str());
+                    }
+                    (Directive::Codes(_, codes), matches) => {
+                        if codes.contains(&check.kind.code().as_str()) {
+                            matches.push(check.kind.code().as_str());
+                        } else {
+                            line_checks.push(check);
+                        }
+                    }
+                    (Directive::None, _) => line_checks.push(check),
                 }
             }
         }
     }
+
+    // Enforce that the noqa directive was actually used.
+    if enforce_noqa {
+        for (row, (directive, matches)) in noqa_directives {
+            match directive {
+                Directive::All(column) => {
+                    if matches.is_empty() {
+                        let mut check = Check::new(
+                            CheckKind::UnusedNOQA(None),
+                            Location::new(row + 1, column + 1),
+                        );
+                        if matches!(autofix, fixer::Mode::Generate | fixer::Mode::Apply) {
+                            check.amend(Fix {
+                                content: "".to_string(),
+                                start: Location::new(row + 1, column + 1),
+                                end: Location::new(row + 1, lines[row].chars().count() + 1),
+                                applied: false,
+                            });
+                        }
+                        line_checks.push(check);
+                    }
+                }
+                Directive::Codes(column, codes) => {
+                    let mut invalid_codes = vec![];
+                    let mut valid_codes = vec![];
+                    for code in codes {
+                        if !matches.contains(&code) {
+                            invalid_codes.push(code);
+                        } else {
+                            valid_codes.push(code);
+                        }
+                    }
+
+                    if !invalid_codes.is_empty() {
+                        let mut check = Check::new(
+                            CheckKind::UnusedNOQA(Some(invalid_codes.join(", "))),
+                            Location::new(row + 1, column + 1),
+                        );
+                        if matches!(autofix, fixer::Mode::Generate | fixer::Mode::Apply) {
+                            if valid_codes.is_empty() {
+                                check.amend(Fix {
+                                    content: "".to_string(),
+                                    start: Location::new(row + 1, column + 1),
+                                    end: Location::new(row + 1, lines[row].chars().count() + 1),
+                                    applied: false,
+                                });
+                            } else {
+                                check.amend(Fix {
+                                    content: format!("  # noqa: {}", valid_codes.join(", ")),
+                                    start: Location::new(row + 1, column + 1),
+                                    end: Location::new(row + 1, lines[row].chars().count() + 1),
+                                    applied: false,
+                                });
+                            }
+                        }
+                        line_checks.push(check);
+                    }
+                }
+                Directive::None => {}
+            }
+        }
+    }
+
     ignored.sort();
     for index in ignored.iter().rev() {
         checks.swap_remove(*index);
@@ -56,22 +180,28 @@ pub fn check_lines(checks: &mut Vec<Check>, contents: &str, settings: &Settings)
 
 #[cfg(test)]
 mod tests {
+    use crate::autofix::fixer;
+    use crate::checks::{Check, CheckCode};
+    use crate::settings;
+
     use super::check_lines;
-    use super::*;
-    use std::collections::BTreeSet;
 
     #[test]
     fn e501_non_ascii_char() {
         let line = "'\u{4e9c}' * 2"; // 7 in UTF-32, 9 in UTF-8.
+        let noqa_line_for: Vec<usize> = vec![1];
         let check_with_max_line_length = |line_length: usize| {
             let mut checks: Vec<Check> = vec![];
-            let settings = Settings {
-                line_length,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from_iter(vec![CheckCode::E501]),
-            };
-            check_lines(&mut checks, line, &settings);
+            check_lines(
+                &mut checks,
+                line,
+                &noqa_line_for,
+                &settings::Settings {
+                    line_length,
+                    ..settings::Settings::for_rule(CheckCode::E501)
+                },
+                &fixer::Mode::Generate,
+            );
             return checks;
         };
         assert!(!check_with_max_line_length(6).is_empty());

src/checks.rs

@@ -1,12 +1,10 @@
 use std::str::FromStr;
 
 use anyhow::Result;
-use once_cell::sync::Lazy;
-use regex::Regex;
 use rustpython_parser::ast::Location;
 use serde::{Deserialize, Serialize};
 
-pub const ALL_CHECK_CODES: [CheckCode; 42] = [
+pub const DEFAULT_CHECK_CODES: [CheckCode; 45] = [
     CheckCode::E402,
     CheckCode::E501,
     CheckCode::E711,
@@ -22,8 +20,10 @@ pub const ALL_CHECK_CODES: [CheckCode; 42] = [
     CheckCode::E902,
     CheckCode::E999,
     CheckCode::F401,
+    CheckCode::F402,
     CheckCode::F403,
     CheckCode::F404,
+    CheckCode::F405,
     CheckCode::F406,
     CheckCode::F407,
     CheckCode::F541,
@@ -47,8 +47,62 @@ pub const ALL_CHECK_CODES: [CheckCode; 42] = [
     CheckCode::F831,
     CheckCode::F841,
     CheckCode::F901,
+    // flake8-builtins
+    CheckCode::A001,
+    CheckCode::A002,
+    CheckCode::A003,
+];
+
+pub const ALL_CHECK_CODES: [CheckCode; 48] = [
+    CheckCode::E402,
+    CheckCode::E501,
+    CheckCode::E711,
+    CheckCode::E712,
+    CheckCode::E713,
+    CheckCode::E714,
+    CheckCode::E721,
+    CheckCode::E722,
+    CheckCode::E731,
+    CheckCode::E741,
+    CheckCode::E742,
+    CheckCode::E743,
+    CheckCode::E902,
+    CheckCode::E999,
+    CheckCode::F401,
+    CheckCode::F402,
+    CheckCode::F403,
+    CheckCode::F404,
+    CheckCode::F405,
+    CheckCode::F406,
+    CheckCode::F407,
+    CheckCode::F541,
+    CheckCode::F601,
+    CheckCode::F602,
+    CheckCode::F621,
+    CheckCode::F622,
+    CheckCode::F631,
+    CheckCode::F632,
+    CheckCode::F633,
+    CheckCode::F634,
+    CheckCode::F701,
+    CheckCode::F702,
+    CheckCode::F704,
+    CheckCode::F706,
+    CheckCode::F707,
+    CheckCode::F722,
+    CheckCode::F821,
+    CheckCode::F822,
+    CheckCode::F823,
+    CheckCode::F831,
+    CheckCode::F841,
+    CheckCode::F901,
+    CheckCode::M001,
     CheckCode::R001,
     CheckCode::R002,
+    // flake8-builtins
+    CheckCode::A001,
+    CheckCode::A002,
+    CheckCode::A003,
 ];
 
 #[derive(Debug, PartialEq, Eq, Clone, Serialize, Deserialize, Hash, PartialOrd, Ord)]
@@ -68,8 +122,10 @@ pub enum CheckCode {
     E902,
     E999,
     F401,
+    F402,
     F403,
     F404,
+    F405,
     F406,
     F407,
     F541,
@@ -95,6 +151,11 @@ pub enum CheckCode {
     F901,
     R001,
     R002,
+    M001,
+    // flake8-builtins
+    A001,
+    A002,
+    A003,
 }
 
 impl FromStr for CheckCode {
@@ -117,8 +178,10 @@ impl FromStr for CheckCode {
             "E902" => Ok(CheckCode::E902),
             "E999" => Ok(CheckCode::E999),
             "F401" => Ok(CheckCode::F401),
+            "F402" => Ok(CheckCode::F402),
             "F403" => Ok(CheckCode::F403),
             "F404" => Ok(CheckCode::F404),
+            "F405" => Ok(CheckCode::F405),
             "F406" => Ok(CheckCode::F406),
             "F407" => Ok(CheckCode::F407),
             "F541" => Ok(CheckCode::F541),
@@ -144,6 +207,11 @@ impl FromStr for CheckCode {
             "F901" => Ok(CheckCode::F901),
             "R001" => Ok(CheckCode::R001),
             "R002" => Ok(CheckCode::R002),
+            "M001" => Ok(CheckCode::M001),
+            // flake8-builtins
+            "A001" => Ok(CheckCode::A001),
+            "A002" => Ok(CheckCode::A002),
+            "A003" => Ok(CheckCode::A003),
             _ => Err(anyhow::anyhow!("Unknown check code: {s}")),
         }
     }
@@ -167,8 +235,10 @@ impl CheckCode {
             CheckCode::E902 => "E902",
             CheckCode::E999 => "E999",
             CheckCode::F401 => "F401",
+            CheckCode::F402 => "F402",
             CheckCode::F403 => "F403",
             CheckCode::F404 => "F404",
+            CheckCode::F405 => "F405",
             CheckCode::F406 => "F406",
             CheckCode::F407 => "F407",
             CheckCode::F541 => "F541",
@@ -194,14 +264,19 @@ impl CheckCode {
             CheckCode::F901 => "F901",
             CheckCode::R001 => "R001",
             CheckCode::R002 => "R002",
+            CheckCode::M001 => "M001",
+            // flake8-builtins
+            CheckCode::A001 => "A001",
+            CheckCode::A002 => "A002",
+            CheckCode::A003 => "A003",
         }
     }
 
     /// The source for the check (either the AST, the filesystem, or the physical lines).
     pub fn lint_source(&self) -> &'static LintSource {
         match self {
-            CheckCode::E501 => &LintSource::Lines,
-            CheckCode::E902 | CheckCode::E999 => &LintSource::FileSystem,
+            CheckCode::E501 | CheckCode::M001 => &LintSource::Lines,
+            CheckCode::E902 => &LintSource::FileSystem,
             _ => &LintSource::AST,
         }
     }
@@ -209,48 +284,55 @@ impl CheckCode {
     /// A placeholder representation of the CheckKind for the check.
     pub fn kind(&self) -> CheckKind {
         match self {
-            CheckCode::E742 => CheckKind::AmbiguousClassName("...".to_string()),
-            CheckCode::E743 => CheckKind::AmbiguousFunctionName("...".to_string()),
-            CheckCode::E741 => CheckKind::AmbiguousVariableName("...".to_string()),
-            CheckCode::F631 => CheckKind::AssertTuple,
-            CheckCode::F701 => CheckKind::BreakOutsideLoop,
-            CheckCode::F702 => CheckKind::ContinueOutsideLoop,
-            CheckCode::F707 => CheckKind::DefaultExceptNotLast,
-            CheckCode::E731 => CheckKind::DoNotAssignLambda,
-            CheckCode::E722 => CheckKind::DoNotUseBareExcept,
-            CheckCode::F831 => CheckKind::DuplicateArgumentName,
-            CheckCode::F541 => CheckKind::FStringMissingPlaceholders,
-            CheckCode::F722 => CheckKind::ForwardAnnotationSyntaxError("...".to_string()),
-            CheckCode::F407 => CheckKind::FutureFeatureNotDefined("...".to_string()),
-            CheckCode::E902 => CheckKind::IOError("...".to_string()),
-            CheckCode::F634 => CheckKind::IfTuple,
-            CheckCode::F406 => CheckKind::ImportStarNotPermitted("...".to_string()),
-            CheckCode::F403 => CheckKind::ImportStarUsage("...".to_string()),
-            CheckCode::F633 => CheckKind::InvalidPrintSyntax,
-            CheckCode::F632 => CheckKind::IsLiteral,
-            CheckCode::F404 => CheckKind::LateFutureImport,
-            CheckCode::E501 => CheckKind::LineTooLong(89, 88),
             CheckCode::E402 => CheckKind::ModuleImportNotAtTopOfFile,
-            CheckCode::F601 => CheckKind::MultiValueRepeatedKeyLiteral,
-            CheckCode::F602 => CheckKind::MultiValueRepeatedKeyVariable("...".to_string()),
-            CheckCode::R002 => CheckKind::NoAssertEquals,
+            CheckCode::E501 => CheckKind::LineTooLong(89, 88),
             CheckCode::E711 => CheckKind::NoneComparison(RejectedCmpop::Eq),
+            CheckCode::E712 => CheckKind::TrueFalseComparison(true, RejectedCmpop::Eq),
             CheckCode::E713 => CheckKind::NotInTest,
             CheckCode::E714 => CheckKind::NotIsTest,
-            CheckCode::F901 => CheckKind::RaiseNotImplemented,
-            CheckCode::F706 => CheckKind::ReturnOutsideFunction,
-            CheckCode::E999 => CheckKind::SyntaxError("...".to_string()),
-            CheckCode::F621 => CheckKind::TooManyExpressionsInStarredAssignment,
-            CheckCode::E712 => CheckKind::TrueFalseComparison(true, RejectedCmpop::Eq),
-            CheckCode::F622 => CheckKind::TwoStarredExpressions,
             CheckCode::E721 => CheckKind::TypeComparison,
+            CheckCode::E722 => CheckKind::DoNotUseBareExcept,
+            CheckCode::E731 => CheckKind::DoNotAssignLambda,
+            CheckCode::E741 => CheckKind::AmbiguousVariableName("...".to_string()),
+            CheckCode::E742 => CheckKind::AmbiguousClassName("...".to_string()),
+            CheckCode::E743 => CheckKind::AmbiguousFunctionName("...".to_string()),
+            CheckCode::E902 => CheckKind::IOError("...".to_string()),
+            CheckCode::E999 => CheckKind::SyntaxError("...".to_string()),
+            CheckCode::F401 => CheckKind::UnusedImport("...".to_string()),
+            CheckCode::F402 => CheckKind::ImportShadowedByLoopVar("...".to_string(), 1),
+            CheckCode::F403 => CheckKind::ImportStarUsed("...".to_string()),
+            CheckCode::F404 => CheckKind::LateFutureImport,
+            CheckCode::F405 => CheckKind::ImportStarUsage("...".to_string(), "...".to_string()),
+            CheckCode::F406 => CheckKind::ImportStarNotPermitted("...".to_string()),
+            CheckCode::F407 => CheckKind::FutureFeatureNotDefined("...".to_string()),
+            CheckCode::F541 => CheckKind::FStringMissingPlaceholders,
+            CheckCode::F601 => CheckKind::MultiValueRepeatedKeyLiteral,
+            CheckCode::F602 => CheckKind::MultiValueRepeatedKeyVariable("...".to_string()),
+            CheckCode::F621 => CheckKind::TooManyExpressionsInStarredAssignment,
+            CheckCode::F622 => CheckKind::TwoStarredExpressions,
+            CheckCode::F631 => CheckKind::AssertTuple,
+            CheckCode::F632 => CheckKind::IsLiteral,
+            CheckCode::F633 => CheckKind::InvalidPrintSyntax,
+            CheckCode::F634 => CheckKind::IfTuple,
+            CheckCode::F701 => CheckKind::BreakOutsideLoop,
+            CheckCode::F702 => CheckKind::ContinueOutsideLoop,
+            CheckCode::F704 => CheckKind::YieldOutsideFunction,
+            CheckCode::F706 => CheckKind::ReturnOutsideFunction,
+            CheckCode::F707 => CheckKind::DefaultExceptNotLast,
+            CheckCode::F722 => CheckKind::ForwardAnnotationSyntaxError("...".to_string()),
+            CheckCode::F821 => CheckKind::UndefinedName("...".to_string()),
             CheckCode::F822 => CheckKind::UndefinedExport("...".to_string()),
             CheckCode::F823 => CheckKind::UndefinedLocal("...".to_string()),
-            CheckCode::F821 => CheckKind::UndefinedName("...".to_string()),
-            CheckCode::F401 => CheckKind::UnusedImport("...".to_string()),
+            CheckCode::F831 => CheckKind::DuplicateArgumentName,
             CheckCode::F841 => CheckKind::UnusedVariable("...".to_string()),
+            CheckCode::F901 => CheckKind::RaiseNotImplemented,
+            CheckCode::M001 => CheckKind::UnusedNOQA(None),
             CheckCode::R001 => CheckKind::UselessObjectInheritance("...".to_string()),
-            CheckCode::F704 => CheckKind::YieldOutsideFunction,
+            CheckCode::R002 => CheckKind::NoAssertEquals,
+            // flake8-builtins
+            CheckCode::A001 => CheckKind::BuiltinVariableShadowing("...".to_string()),
+            CheckCode::A002 => CheckKind::BuiltinArgumentShadowing("...".to_string()),
+            CheckCode::A003 => CheckKind::BuiltinAttributeShadowing("...".to_string()),
         }
     }
 }
@@ -270,6 +352,7 @@ pub enum RejectedCmpop {
 
 #[derive(Debug, PartialEq, Eq, Serialize, Deserialize)]
 pub enum CheckKind {
+    UnusedNOQA(Option<String>),
     AmbiguousClassName(String),
     AmbiguousFunctionName(String),
     AmbiguousVariableName(String),
@@ -285,8 +368,10 @@ pub enum CheckKind {
     FutureFeatureNotDefined(String),
     IOError(String),
     IfTuple,
+    ImportShadowedByLoopVar(String, usize),
     ImportStarNotPermitted(String),
-    ImportStarUsage(String),
+    ImportStarUsage(String, String),
+    ImportStarUsed(String),
     InvalidPrintSyntax,
     IsLiteral,
     LateFutureImport,
@@ -312,6 +397,10 @@ pub enum CheckKind {
     UnusedVariable(String),
     UselessObjectInheritance(String),
     YieldOutsideFunction,
+    // flake8-builtin
+    BuiltinVariableShadowing(String),
+    BuiltinArgumentShadowing(String),
+    BuiltinAttributeShadowing(String),
 }
 
 impl CheckKind {
@@ -333,8 +422,10 @@ impl CheckKind {
             CheckKind::FutureFeatureNotDefined(_) => "FutureFeatureNotDefined",
             CheckKind::IOError(_) => "IOError",
             CheckKind::IfTuple => "IfTuple",
+            CheckKind::ImportShadowedByLoopVar(_, _) => "ImportShadowedByLoopVar",
             CheckKind::ImportStarNotPermitted(_) => "ImportStarNotPermitted",
-            CheckKind::ImportStarUsage(_) => "ImportStarUsage",
+            CheckKind::ImportStarUsage(_, _) => "ImportStarUsage",
+            CheckKind::ImportStarUsed(_) => "ImportStarUsed",
             CheckKind::InvalidPrintSyntax => "InvalidPrintSyntax",
             CheckKind::IsLiteral => "IsLiteral",
             CheckKind::LateFutureImport => "LateFutureImport",
@@ -362,6 +453,11 @@ impl CheckKind {
             CheckKind::UnusedVariable(_) => "UnusedVariable",
             CheckKind::UselessObjectInheritance(_) => "UselessObjectInheritance",
             CheckKind::YieldOutsideFunction => "YieldOutsideFunction",
+            CheckKind::UnusedNOQA(_) => "UnusedNOQA",
+            // flake8-builtins
+            CheckKind::BuiltinVariableShadowing(_) => "BuiltinVariableShadowing",
+            CheckKind::BuiltinArgumentShadowing(_) => "BuiltinArgumentShadowing",
+            CheckKind::BuiltinAttributeShadowing(_) => "BuiltinAttributeShadowing",
         }
     }
 
@@ -383,8 +479,10 @@ impl CheckKind {
             CheckKind::FutureFeatureNotDefined(_) => &CheckCode::F407,
             CheckKind::IOError(_) => &CheckCode::E902,
             CheckKind::IfTuple => &CheckCode::F634,
+            CheckKind::ImportShadowedByLoopVar(_, _) => &CheckCode::F402,
             CheckKind::ImportStarNotPermitted(_) => &CheckCode::F406,
-            CheckKind::ImportStarUsage(_) => &CheckCode::F403,
+            CheckKind::ImportStarUsage(_, _) => &CheckCode::F405,
+            CheckKind::ImportStarUsed(_) => &CheckCode::F403,
             CheckKind::InvalidPrintSyntax => &CheckCode::F633,
             CheckKind::IsLiteral => &CheckCode::F632,
             CheckKind::LateFutureImport => &CheckCode::F404,
@@ -407,9 +505,14 @@ impl CheckKind {
             CheckKind::UndefinedLocal(_) => &CheckCode::F823,
             CheckKind::UndefinedName(_) => &CheckCode::F821,
             CheckKind::UnusedImport(_) => &CheckCode::F401,
+            CheckKind::UnusedNOQA(_) => &CheckCode::M001,
             CheckKind::UnusedVariable(_) => &CheckCode::F841,
             CheckKind::UselessObjectInheritance(_) => &CheckCode::R001,
             CheckKind::YieldOutsideFunction => &CheckCode::F704,
+            // flake8-builtins
+            CheckKind::BuiltinVariableShadowing(_) => &CheckCode::A001,
+            CheckKind::BuiltinArgumentShadowing(_) => &CheckCode::A002,
+            CheckKind::BuiltinAttributeShadowing(_) => &CheckCode::A003,
         }
     }
 
@@ -449,17 +552,21 @@ impl CheckKind {
             CheckKind::FutureFeatureNotDefined(name) => {
                 format!("future feature '{name}' is not defined")
             }
-            CheckKind::IOError(name) => {
-                format!("No such file or directory: `{name}`")
-            }
+            CheckKind::IOError(message) => message.clone(),
             CheckKind::IfTuple => "If test is a tuple, which is always `True`".to_string(),
             CheckKind::InvalidPrintSyntax => "use of >> is invalid with print function".to_string(),
+            CheckKind::ImportShadowedByLoopVar(name, line) => {
+                format!("import '{name}' from line {line} shadowed by loop variable")
+            }
             CheckKind::ImportStarNotPermitted(name) => {
                 format!("`from {name} import *` only allowed at module level")
             }
-            CheckKind::ImportStarUsage(name) => {
+            CheckKind::ImportStarUsed(name) => {
                 format!("`from {name} import *` used; unable to detect undefined names")
             }
+            CheckKind::ImportStarUsage(name, sources) => {
+                format!("'{name}' may be undefined, or defined from star imports: {sources}")
+            }
             CheckKind::IsLiteral => "use ==/!= to compare constant literals".to_string(),
             CheckKind::LateFutureImport => {
                 "from __future__ imports must occur at the beginning of the file".to_string()
@@ -536,6 +643,20 @@ impl CheckKind {
             CheckKind::YieldOutsideFunction => {
                 "a `yield` or `yield from` statement outside of a function/method".to_string()
             }
+            CheckKind::UnusedNOQA(code) => match code {
+                None => "Unused `noqa` directive".to_string(),
+                Some(code) => format!("Unused `noqa` directive for: {code}"),
+            },
+            // flake8-builtins
+            CheckKind::BuiltinVariableShadowing(name) => {
+                format!("Variable `{name}` is shadowing a python builtin")
+            }
+            CheckKind::BuiltinArgumentShadowing(name) => {
+                format!("Argument `{name}` is shadowing a python builtin")
+            }
+            CheckKind::BuiltinAttributeShadowing(name) => {
+                format!("class attribute `{name}` is shadowing a python builtin")
+            }
         }
     }
 
@@ -543,7 +664,9 @@ impl CheckKind {
     pub fn fixable(&self) -> bool {
         matches!(
             self,
-            CheckKind::NoAssertEquals | CheckKind::UselessObjectInheritance(_)
+            CheckKind::NoAssertEquals
+                | CheckKind::UselessObjectInheritance(_)
+                | CheckKind::UnusedNOQA(_)
         )
     }
 }
@@ -563,11 +686,6 @@ pub struct Check {
     pub fix: Option<Fix>,
 }
 
-static NO_QA_REGEX: Lazy<Regex> = Lazy::new(|| {
-    Regex::new(r"(?i)# noqa(?::\s?(?P<codes>([A-Z]+[0-9]+(?:[,\s]+)?)+))?").expect("Invalid regex")
-});
-static SPLIT_COMMA_REGEX: Lazy<Regex> = Lazy::new(|| Regex::new(r"[,\s]").expect("Invalid regex"));
-
 impl Check {
     pub fn new(kind: CheckKind, location: Location) -> Self {
         Self {
@@ -580,25 +698,4 @@ impl Check {
     pub fn amend(&mut self, fix: Fix) {
         self.fix = Some(fix);
     }
-
-    pub fn is_inline_ignored(&self, line: &str) -> bool {
-        match NO_QA_REGEX.captures(line) {
-            Some(caps) => match caps.name("codes") {
-                Some(codes) => {
-                    for code in SPLIT_COMMA_REGEX
-                        .split(codes.as_str())
-                        .map(|code| code.trim())
-                        .filter(|code| !code.is_empty())
-                    {
-                        if code == self.kind.code().as_str() {
-                            return true;
-                        }
-                    }
-                    false
-                }
-                None => true,
-            },
-            None => false,
-        }
-    }
 }

src/fs.rs

@@ -1,4 +1,5 @@
 use std::borrow::Cow;
+use std::collections::BTreeSet;
 use std::fs::File;
 use std::io::{BufReader, Read};
 use std::ops::Deref;
@@ -10,7 +11,8 @@ use path_absolutize::path_dedot;
 use path_absolutize::Absolutize;
 use walkdir::{DirEntry, WalkDir};
 
-use crate::settings::FilePattern;
+use crate::checks::CheckCode;
+use crate::settings::{FilePattern, PerFileIgnore};
 
 /// Extract the absolute path and basename (as strings) from a Path.
 fn extract_path_names(path: &Path) -> Result<(&str, &str)> {
@@ -25,9 +27,12 @@ fn extract_path_names(path: &Path) -> Result<(&str, &str)> {
     Ok((file_path, file_basename))
 }
 
-fn is_excluded(file_path: &str, file_basename: &str, exclude: &[FilePattern]) -> bool {
+fn is_excluded<'a, T>(file_path: &str, file_basename: &str, exclude: T) -> bool
+where
+    T: Iterator<Item = &'a FilePattern>,
+{
     for pattern in exclude {
-        match &pattern {
+        match pattern {
             FilePattern::Simple(basename) => {
                 if *basename == file_basename {
                     return true;
@@ -45,7 +50,7 @@ fn is_excluded(file_path: &str, file_basename: &str, exclude: &[FilePattern]) ->
                     return true;
                 }
             }
-        }
+        };
     }
     false
 }
@@ -59,19 +64,18 @@ pub fn iter_python_files<'a>(
     path: &'a Path,
     exclude: &'a [FilePattern],
     extend_exclude: &'a [FilePattern],
-) -> impl Iterator<Item = DirEntry> + 'a {
+) -> impl Iterator<Item = Result<DirEntry, walkdir::Error>> + 'a {
     // Run some checks over the provided patterns, to enable optimizations below.
     let has_exclude = !exclude.is_empty();
     let has_extend_exclude = !extend_exclude.is_empty();
     let exclude_simple = exclude
         .iter()
         .all(|pattern| matches!(pattern, FilePattern::Simple(_)));
-    let extend_exclude_simple = exclude
+    let extend_exclude_simple = extend_exclude
         .iter()
         .all(|pattern| matches!(pattern, FilePattern::Simple(_)));
 
     WalkDir::new(normalize_path(path))
-        .follow_links(true)
         .into_iter()
         .filter_entry(move |entry| {
             if !has_exclude && !has_extend_exclude {
@@ -85,13 +89,13 @@ pub fn iter_python_files<'a>(
 
                     if has_exclude
                         && (!exclude_simple || file_type.is_dir())
-                        && is_excluded(file_path, file_basename, exclude)
+                        && is_excluded(file_path, file_basename, exclude.iter())
                     {
                         debug!("Ignored path via `exclude`: {:?}", path);
                         false
                     } else if has_extend_exclude
                         && (!extend_exclude_simple || file_type.is_dir())
-                        && is_excluded(file_path, file_basename, extend_exclude)
+                        && is_excluded(file_path, file_basename, extend_exclude.iter())
                     {
                         debug!("Ignored path via `extend-exclude`: {:?}", path);
                         false
@@ -105,18 +109,36 @@ pub fn iter_python_files<'a>(
                 }
             }
         })
-        .filter_map(|entry| entry.ok())
         .filter(|entry| {
-            let path = entry.path();
-            is_included(path)
+            entry.as_ref().map_or(true, |entry| {
+                (entry.depth() == 0 || is_included(entry.path()))
+                    && !entry.file_type().is_dir()
+                    && !(entry.file_type().is_symlink() && entry.path().is_dir())
+            })
         })
 }
 
+/// Create tree set with codes matching the pattern/code pairs.
+pub fn ignores_from_path<'a>(
+    path: &Path,
+    pattern_code_pairs: &'a [PerFileIgnore],
+) -> Result<BTreeSet<&'a CheckCode>> {
+    let (file_path, file_basename) = extract_path_names(path)?;
+    Ok(pattern_code_pairs
+        .iter()
+        .filter(|pattern_code_pair| {
+            is_excluded(
+                file_path,
+                file_basename,
+                [&pattern_code_pair.pattern].into_iter(),
+            )
+        })
+        .map(|pattern_code_pair| &pattern_code_pair.code)
+        .collect())
+}
+
 /// Convert any path to an absolute path (based on the current working directory).
 pub fn normalize_path(path: &Path) -> PathBuf {
-    if path == Path::new(".") || path == Path::new("..") {
-        return path.to_path_buf();
-    }
     if let Ok(path) = path.absolutize() {
         return path.to_path_buf();
     }
@@ -125,9 +147,6 @@ pub fn normalize_path(path: &Path) -> PathBuf {
 
 /// Convert any path to an absolute path (based on the specified project root).
 pub fn normalize_path_to(path: &Path, project_root: &Path) -> PathBuf {
-    if path == Path::new(".") || path == Path::new("..") {
-        return path.to_path_buf();
-    }
     if let Ok(path) = path.absolutize_from(project_root) {
         return path.to_path_buf();
     }
@@ -186,7 +205,7 @@ mod tests {
             &Some(project_root.to_path_buf()),
         )];
         let (file_path, file_basename) = extract_path_names(&path)?;
-        assert!(is_excluded(file_path, file_basename, &exclude));
+        assert!(is_excluded(file_path, file_basename, exclude.iter()));
 
         let path = Path::new("foo/bar").absolutize_from(project_root).unwrap();
         let exclude = vec![FilePattern::from_user(
@@ -194,7 +213,7 @@ mod tests {
             &Some(project_root.to_path_buf()),
         )];
         let (file_path, file_basename) = extract_path_names(&path)?;
-        assert!(is_excluded(file_path, file_basename, &exclude));
+        assert!(is_excluded(file_path, file_basename, exclude.iter()));
 
         let path = Path::new("foo/bar/baz.py")
             .absolutize_from(project_root)
@@ -204,7 +223,7 @@ mod tests {
             &Some(project_root.to_path_buf()),
         )];
         let (file_path, file_basename) = extract_path_names(&path)?;
-        assert!(is_excluded(file_path, file_basename, &exclude));
+        assert!(is_excluded(file_path, file_basename, exclude.iter()));
 
         let path = Path::new("foo/bar").absolutize_from(project_root).unwrap();
         let exclude = vec![FilePattern::from_user(
@@ -212,7 +231,7 @@ mod tests {
             &Some(project_root.to_path_buf()),
         )];
         let (file_path, file_basename) = extract_path_names(&path)?;
-        assert!(is_excluded(file_path, file_basename, &exclude));
+        assert!(is_excluded(file_path, file_basename, exclude.iter()));
 
         let path = Path::new("foo/bar/baz.py")
             .absolutize_from(project_root)
@@ -222,7 +241,7 @@ mod tests {
             &Some(project_root.to_path_buf()),
         )];
         let (file_path, file_basename) = extract_path_names(&path)?;
-        assert!(is_excluded(file_path, file_basename, &exclude));
+        assert!(is_excluded(file_path, file_basename, exclude.iter()));
 
         let path = Path::new("foo/bar/baz.py")
             .absolutize_from(project_root)
@@ -232,7 +251,7 @@ mod tests {
             &Some(project_root.to_path_buf()),
         )];
         let (file_path, file_basename) = extract_path_names(&path)?;
-        assert!(is_excluded(file_path, file_basename, &exclude));
+        assert!(is_excluded(file_path, file_basename, exclude.iter()));
 
         let path = Path::new("foo/bar/baz.py")
             .absolutize_from(project_root)
@@ -242,7 +261,7 @@ mod tests {
             &Some(project_root.to_path_buf()),
         )];
         let (file_path, file_basename) = extract_path_names(&path)?;
-        assert!(!is_excluded(file_path, file_basename, &exclude));
+        assert!(!is_excluded(file_path, file_basename, exclude.iter()));
 
         Ok(())
     }

src/lib.rs

@@ -10,6 +10,7 @@ pub mod fs;
 pub mod linter;
 pub mod logging;
 pub mod message;
+mod noqa;
 pub mod printer;
 pub mod pyproject;
 mod python;

src/linter.rs

@@ -2,20 +2,37 @@ use std::path::Path;
 
 use anyhow::Result;
 use log::debug;
-use rustpython_parser::parser;
+use rustpython_parser::lexer::LexResult;
+use rustpython_parser::{lexer, parser};
 
 use crate::autofix::fixer;
 use crate::autofix::fixer::fix_file;
 use crate::check_ast::check_ast;
 use crate::check_lines::check_lines;
-use crate::checks::{Check, LintSource};
+use crate::checks::{Check, CheckCode, CheckKind, LintSource};
 use crate::message::Message;
+use crate::noqa::add_noqa;
 use crate::settings::Settings;
-use crate::{cache, fs};
+use crate::{cache, fs, noqa};
+
+/// Collect tokens up to and including the first error.
+fn tokenize(contents: &str) -> Vec<LexResult> {
+    let mut tokens: Vec<LexResult> = vec![];
+    for tok in lexer::make_tokenizer(contents) {
+        let is_err = tok.is_err();
+        tokens.push(tok);
+        if is_err {
+            break;
+        }
+    }
+    tokens
+}
 
 fn check_path(
     path: &Path,
     contents: &str,
+    tokens: Vec<LexResult>,
+    noqa_line_for: &[usize],
     settings: &Settings,
     autofix: &fixer::Mode,
 ) -> Result<Vec<Check>> {
@@ -28,12 +45,34 @@ fn check_path(
         .iter()
         .any(|check_code| matches!(check_code.lint_source(), LintSource::AST))
     {
-        let python_ast = parser::parse_program(contents, "<filename>")?;
-        checks.extend(check_ast(&python_ast, contents, settings, autofix, path));
+        match parser::parse_program_tokens(tokens, "<filename>") {
+            Ok(python_ast) => {
+                checks.extend(check_ast(&python_ast, contents, settings, autofix, path))
+            }
+            Err(parse_error) => {
+                if settings.select.contains(&CheckCode::E999) {
+                    checks.push(Check::new(
+                        CheckKind::SyntaxError(parse_error.error.to_string()),
+                        parse_error.location,
+                    ))
+                }
+            }
+        }
     }
 
     // Run the lines-based checks.
-    check_lines(&mut checks, contents, settings);
+    check_lines(&mut checks, contents, noqa_line_for, settings, autofix);
+
+    // Create path ignores.
+    if !checks.is_empty() && !settings.per_file_ignores.is_empty() {
+        let ignores = fs::ignores_from_path(path, &settings.per_file_ignores)?;
+        if !ignores.is_empty() {
+            return Ok(checks
+                .into_iter()
+                .filter(|check| !ignores.contains(check.kind.code()))
+                .collect());
+        }
+    }
 
     Ok(checks)
 }
@@ -55,8 +94,14 @@ pub fn lint_path(
     // Read the file from disk.
     let contents = fs::read_file(path)?;
 
+    // Tokenize once.
+    let tokens: Vec<LexResult> = tokenize(&contents);
+
+    // Determine the noqa line for every line in the source.
+    let noqa_line_for = noqa::extract_noqa_line_for(&tokens);
+
     // Generate checks.
-    let mut checks = check_path(path, &contents, settings, autofix)?;
+    let mut checks = check_path(path, &contents, tokens, &noqa_line_for, settings, autofix)?;
 
     // Apply autofix.
     if matches!(autofix, fixer::Mode::Apply) {
@@ -78,18 +123,43 @@ pub fn lint_path(
     Ok(messages)
 }
 
+pub fn add_noqa_to_path(path: &Path, settings: &Settings) -> Result<usize> {
+    // Read the file from disk.
+    let contents = fs::read_file(path)?;
+
+    // Tokenize once.
+    let tokens: Vec<LexResult> = tokenize(&contents);
+
+    // Determine the noqa line for every line in the source.
+    let noqa_line_for = noqa::extract_noqa_line_for(&tokens);
+
+    // Generate checks.
+    let checks = check_path(
+        path,
+        &contents,
+        tokens,
+        &noqa_line_for,
+        settings,
+        &fixer::Mode::None,
+    )?;
+
+    add_noqa(&checks, &contents, &noqa_line_for, path)
+}
+
 #[cfg(test)]
 mod tests {
-    use std::collections::BTreeSet;
     use std::path::Path;
 
     use anyhow::Result;
+    use regex::Regex;
+    use rustpython_parser::lexer::LexResult;
 
     use crate::autofix::fixer;
     use crate::checks::{Check, CheckCode};
-    use crate::fs;
     use crate::linter;
+    use crate::linter::tokenize;
     use crate::settings;
+    use crate::{fs, noqa};
 
     fn check_path(
         path: &Path,
@@ -97,19 +167,16 @@ mod tests {
         autofix: &fixer::Mode,
     ) -> Result<Vec<Check>> {
         let contents = fs::read_file(path)?;
-        linter::check_path(path, &contents, settings, autofix)
+        let tokens: Vec<LexResult> = tokenize(&contents);
+        let noqa_line_for = noqa::extract_noqa_line_for(&tokens);
+        linter::check_path(path, &contents, tokens, &noqa_line_for, settings, autofix)
     }
 
     #[test]
     fn e402() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/E402.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::E402]),
-            },
+            &settings::Settings::for_rule(CheckCode::E402),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -121,12 +188,7 @@ mod tests {
     fn e501() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/E501.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::E501]),
-            },
+            &settings::Settings::for_rule(CheckCode::E501),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -138,12 +200,7 @@ mod tests {
     fn e711() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/E711.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::E711]),
-            },
+            &settings::Settings::for_rule(CheckCode::E711),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -155,12 +212,7 @@ mod tests {
     fn e712() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/E712.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::E712]),
-            },
+            &settings::Settings::for_rule(CheckCode::E712),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -172,12 +224,7 @@ mod tests {
     fn e713() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/E713.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::E713]),
-            },
+            &settings::Settings::for_rule(CheckCode::E713),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -189,12 +236,7 @@ mod tests {
     fn e721() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/E721.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::E721]),
-            },
+            &settings::Settings::for_rule(CheckCode::E721),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -206,12 +248,7 @@ mod tests {
     fn e722() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/E722.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::E722]),
-            },
+            &settings::Settings::for_rule(CheckCode::E722),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -223,12 +260,7 @@ mod tests {
     fn e714() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/E714.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::E714]),
-            },
+            &settings::Settings::for_rule(CheckCode::E714),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -240,12 +272,7 @@ mod tests {
     fn e731() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/E731.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::E731]),
-            },
+            &settings::Settings::for_rule(CheckCode::E731),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -257,12 +284,7 @@ mod tests {
     fn e741() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/E741.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::E741]),
-            },
+            &settings::Settings::for_rule(CheckCode::E741),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -274,12 +296,7 @@ mod tests {
     fn e742() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/E742.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::E742]),
-            },
+            &settings::Settings::for_rule(CheckCode::E742),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -291,12 +308,7 @@ mod tests {
     fn e743() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/E743.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::E743]),
-            },
+            &settings::Settings::for_rule(CheckCode::E743),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -308,12 +320,19 @@ mod tests {
     fn f401() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/F401.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::F401]),
-            },
+            &settings::Settings::for_rule(CheckCode::F401),
+            &fixer::Mode::Generate,
+        )?;
+        checks.sort_by_key(|check| check.location);
+        insta::assert_yaml_snapshot!(checks);
+        Ok(())
+    }
+
+    #[test]
+    fn f402() -> Result<()> {
+        let mut checks = check_path(
+            Path::new("./resources/test/fixtures/F402.py"),
+            &settings::Settings::for_rule(CheckCode::F402),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -325,12 +344,7 @@ mod tests {
     fn f403() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/F403.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::F403]),
-            },
+            &settings::Settings::for_rule(CheckCode::F403),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -342,12 +356,19 @@ mod tests {
     fn f404() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/F404.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::F404]),
-            },
+            &settings::Settings::for_rule(CheckCode::F404),
+            &fixer::Mode::Generate,
+        )?;
+        checks.sort_by_key(|check| check.location);
+        insta::assert_yaml_snapshot!(checks);
+        Ok(())
+    }
+
+    #[test]
+    fn f405() -> Result<()> {
+        let mut checks = check_path(
+            Path::new("./resources/test/fixtures/F405.py"),
+            &settings::Settings::for_rule(CheckCode::F405),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -359,12 +380,7 @@ mod tests {
     fn f406() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/F406.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::F406]),
-            },
+            &settings::Settings::for_rule(CheckCode::F406),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -376,12 +392,7 @@ mod tests {
     fn f407() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/F407.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::F407]),
-            },
+            &settings::Settings::for_rule(CheckCode::F407),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -393,12 +404,7 @@ mod tests {
     fn f541() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/F541.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::F541]),
-            },
+            &settings::Settings::for_rule(CheckCode::F541),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -410,12 +416,7 @@ mod tests {
     fn f601() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/F601.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::F601]),
-            },
+            &settings::Settings::for_rule(CheckCode::F601),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -427,12 +428,7 @@ mod tests {
     fn f602() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/F602.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::F602]),
-            },
+            &settings::Settings::for_rule(CheckCode::F602),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -444,12 +440,7 @@ mod tests {
     fn f622() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/F622.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::F622]),
-            },
+            &settings::Settings::for_rule(CheckCode::F622),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -461,12 +452,7 @@ mod tests {
     fn f631() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/F631.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::F631]),
-            },
+            &settings::Settings::for_rule(CheckCode::F631),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -478,12 +464,7 @@ mod tests {
     fn f632() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/F632.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::F632]),
-            },
+            &settings::Settings::for_rule(CheckCode::F632),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -495,12 +476,7 @@ mod tests {
     fn f633() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/F633.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::F633]),
-            },
+            &settings::Settings::for_rule(CheckCode::F633),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -512,12 +488,7 @@ mod tests {
     fn f634() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/F634.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::F634]),
-            },
+            &settings::Settings::for_rule(CheckCode::F634),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -529,12 +500,7 @@ mod tests {
     fn f701() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/F701.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::F701]),
-            },
+            &settings::Settings::for_rule(CheckCode::F701),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -546,12 +512,7 @@ mod tests {
     fn f702() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/F702.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::F702]),
-            },
+            &settings::Settings::for_rule(CheckCode::F702),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -563,12 +524,7 @@ mod tests {
     fn f704() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/F704.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::F704]),
-            },
+            &settings::Settings::for_rule(CheckCode::F704),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -580,12 +536,7 @@ mod tests {
     fn f706() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/F706.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::F706]),
-            },
+            &settings::Settings::for_rule(CheckCode::F706),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -597,12 +548,7 @@ mod tests {
     fn f707() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/F707.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::F707]),
-            },
+            &settings::Settings::for_rule(CheckCode::F707),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -614,12 +560,7 @@ mod tests {
     fn f722() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/F722.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::F722]),
-            },
+            &settings::Settings::for_rule(CheckCode::F722),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -631,12 +572,7 @@ mod tests {
     fn f821() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/F821.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::F821]),
-            },
+            &settings::Settings::for_rule(CheckCode::F821),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -648,12 +584,7 @@ mod tests {
     fn f822() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/F822.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::F822]),
-            },
+            &settings::Settings::for_rule(CheckCode::F822),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -665,12 +596,7 @@ mod tests {
     fn f823() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/F823.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::F823]),
-            },
+            &settings::Settings::for_rule(CheckCode::F823),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -682,12 +608,7 @@ mod tests {
     fn f831() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/F831.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::F831]),
-            },
+            &settings::Settings::for_rule(CheckCode::F831),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -697,13 +618,23 @@ mod tests {
 
     #[test]
     fn f841() -> Result<()> {
+        let mut checks = check_path(
+            Path::new("./resources/test/fixtures/F841.py"),
+            &settings::Settings::for_rule(CheckCode::F841),
+            &fixer::Mode::Generate,
+        )?;
+        checks.sort_by_key(|check| check.location);
+        insta::assert_yaml_snapshot!(checks);
+        Ok(())
+    }
+
+    #[test]
+    fn f841_dummy_variable_rgx() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/F841.py"),
             &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::F841]),
+                dummy_variable_rgx: Regex::new(r"^z$").unwrap(),
+                ..settings::Settings::for_rule(CheckCode::F841)
             },
             &fixer::Mode::Generate,
         )?;
@@ -716,12 +647,19 @@ mod tests {
     fn f901() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/F901.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::F901]),
-            },
+            &settings::Settings::for_rule(CheckCode::F901),
+            &fixer::Mode::Generate,
+        )?;
+        checks.sort_by_key(|check| check.location);
+        insta::assert_yaml_snapshot!(checks);
+        Ok(())
+    }
+
+    #[test]
+    fn m001() -> Result<()> {
+        let mut checks = check_path(
+            Path::new("./resources/test/fixtures/M001.py"),
+            &settings::Settings::for_rules(vec![CheckCode::M001, CheckCode::E501, CheckCode::F841]),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -733,12 +671,7 @@ mod tests {
     fn r001() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/R001.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::R001]),
-            },
+            &settings::Settings::for_rule(CheckCode::R001),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -750,12 +683,7 @@ mod tests {
     fn r002() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/R002.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::R002]),
-            },
+            &settings::Settings::for_rule(CheckCode::R002),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -767,12 +695,7 @@ mod tests {
     fn init() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/__init__.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::F821, CheckCode::F822]),
-            },
+            &settings::Settings::for_rules(vec![CheckCode::F821, CheckCode::F822]),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);
@@ -784,12 +707,55 @@ mod tests {
     fn future_annotations() -> Result<()> {
         let mut checks = check_path(
             Path::new("./resources/test/fixtures/future_annotations.py"),
-            &settings::Settings {
-                line_length: 88,
-                exclude: vec![],
-                extend_exclude: vec![],
-                select: BTreeSet::from([CheckCode::F401, CheckCode::F821]),
-            },
+            &settings::Settings::for_rules(vec![CheckCode::F401, CheckCode::F821]),
+            &fixer::Mode::Generate,
+        )?;
+        checks.sort_by_key(|check| check.location);
+        insta::assert_yaml_snapshot!(checks);
+        Ok(())
+    }
+
+    #[test]
+    fn e999() -> Result<()> {
+        let mut checks = check_path(
+            Path::new("./resources/test/fixtures/E999.py"),
+            &settings::Settings::for_rule(CheckCode::E999),
+            &fixer::Mode::Generate,
+        )?;
+        checks.sort_by_key(|check| check.location);
+        insta::assert_yaml_snapshot!(checks);
+        Ok(())
+    }
+
+    #[test]
+    fn a001() -> Result<()> {
+        let mut checks = check_path(
+            Path::new("./resources/test/fixtures/A001.py"),
+            &settings::Settings::for_rule(CheckCode::A001),
+            &fixer::Mode::Generate,
+        )?;
+        checks.sort_by_key(|check| check.location);
+        insta::assert_yaml_snapshot!(checks);
+        Ok(())
+    }
+
+    #[test]
+    fn a002() -> Result<()> {
+        let mut checks = check_path(
+            Path::new("./resources/test/fixtures/A002.py"),
+            &settings::Settings::for_rule(CheckCode::A002),
+            &fixer::Mode::Generate,
+        )?;
+        checks.sort_by_key(|check| check.location);
+        insta::assert_yaml_snapshot!(checks);
+        Ok(())
+    }
+
+    #[test]
+    fn a003() -> Result<()> {
+        let mut checks = check_path(
+            Path::new("./resources/test/fixtures/A003.py"),
+            &settings::Settings::for_rule(CheckCode::A003),
             &fixer::Mode::Generate,
         )?;
         checks.sort_by_key(|check| check.location);

src/main.rs

@@ -1,73 +1,97 @@
 extern crate core;
 
-use std::path::PathBuf;
+use std::io;
+use std::path::{Path, PathBuf};
 use std::process::ExitCode;
 use std::sync::mpsc::channel;
 use std::time::Instant;
 
 use anyhow::Result;
-use clap::{Parser, ValueHint};
+use clap::{command, Parser};
 use colored::Colorize;
 use log::{debug, error};
 use notify::{raw_watcher, RecursiveMode, Watcher};
 use rayon::prelude::*;
+use regex::Regex;
 use walkdir::DirEntry;
 
 use ::ruff::cache;
 use ::ruff::checks::CheckCode;
 use ::ruff::checks::CheckKind;
 use ::ruff::fs::iter_python_files;
+use ::ruff::linter::add_noqa_to_path;
 use ::ruff::linter::lint_path;
 use ::ruff::logging::set_up_logging;
 use ::ruff::message::Message;
 use ::ruff::printer::{Printer, SerializationFormat};
-use ::ruff::pyproject;
-use ::ruff::settings::{FilePattern, Settings};
+use ::ruff::pyproject::{self, StrCheckCodePair};
+use ::ruff::settings::{FilePattern, PerFileIgnore, Settings};
 use ::ruff::tell_user;
+use ruff::settings::CurrentSettings;
 
 const CARGO_PKG_NAME: &str = env!("CARGO_PKG_NAME");
 const CARGO_PKG_VERSION: &str = env!("CARGO_PKG_VERSION");
 
 #[derive(Debug, Parser)]
-#[clap(name = format!("{CARGO_PKG_NAME} (v{CARGO_PKG_VERSION})"))]
-#[clap(about = "An extremely fast Python linter.", long_about = None)]
-#[clap(version)]
+#[command(author, about = "ruff: An extremely fast Python linter.")]
+#[command(version)]
 struct Cli {
-    #[clap(parse(from_os_str), value_hint = ValueHint::AnyPath, required = true)]
+    #[arg(required = true)]
     files: Vec<PathBuf>,
     /// Enable verbose logging.
-    #[clap(short, long, action)]
+    #[arg(short, long)]
     verbose: bool,
     /// Disable all logging (but still exit with status code "1" upon detecting errors).
-    #[clap(short, long, action)]
+    #[arg(short, long)]
     quiet: bool,
     /// Exit with status code "0", even upon detecting errors.
-    #[clap(short, long, action)]
+    #[arg(short, long)]
     exit_zero: bool,
     /// Run in watch mode by re-running whenever files change.
-    #[clap(short, long, action)]
+    #[arg(short, long)]
     watch: bool,
     /// Attempt to automatically fix lint errors.
-    #[clap(short, long, action)]
+    #[arg(short, long)]
     fix: bool,
     /// Disable cache reads.
-    #[clap(short, long, action)]
+    #[arg(short, long)]
     no_cache: bool,
     /// List of error codes to enable.
-    #[clap(long, multiple = true)]
+    #[arg(long, value_delimiter = ',')]
     select: Vec<CheckCode>,
+    /// Like --select, but adds additional error codes on top of the selected ones.
+    #[arg(long, value_delimiter = ',')]
+    extend_select: Vec<CheckCode>,
     /// List of error codes to ignore.
-    #[clap(long, multiple = true)]
+    #[arg(long, value_delimiter = ',')]
     ignore: Vec<CheckCode>,
+    /// Like --ignore, but adds additional error codes on top of the ignored ones.
+    #[arg(long, value_delimiter = ',')]
+    extend_ignore: Vec<CheckCode>,
     /// List of paths, used to exclude files and/or directories from checks.
-    #[clap(long, multiple = true)]
+    #[arg(long, value_delimiter = ',')]
     exclude: Vec<String>,
     /// Like --exclude, but adds additional files and directories on top of the excluded ones.
-    #[clap(long, multiple = true)]
+    #[arg(long, value_delimiter = ',')]
     extend_exclude: Vec<String>,
+    /// List of mappings from file pattern to code to exclude
+    #[arg(long, value_delimiter = ',')]
+    per_file_ignores: Vec<StrCheckCodePair>,
     /// Output serialization format for error messages.
-    #[clap(long, arg_enum, default_value_t=SerializationFormat::Text)]
+    #[arg(long, value_enum, default_value_t=SerializationFormat::Text)]
     format: SerializationFormat,
+    /// See the files ruff will be run against with the current settings.
+    #[arg(long)]
+    show_files: bool,
+    /// See ruff's settings.
+    #[arg(long)]
+    show_settings: bool,
+    /// Enable automatic additions of noqa directives to failing lines.
+    #[arg(long)]
+    add_noqa: bool,
+    /// Regular expression matching the name of dummy variables.
+    #[arg(long)]
+    dummy_variable_rgx: Option<Regex>,
 }
 
 #[cfg(feature = "update-informer")]
@@ -94,6 +118,22 @@ fn check_for_updates() {
     }
 }
 
+fn show_settings(settings: Settings) {
+    println!("{:#?}", CurrentSettings::from_settings(settings));
+}
+
+fn show_files(files: &[PathBuf], settings: &Settings) {
+    let mut entries: Vec<DirEntry> = files
+        .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 {
+        println!("{}", entry.path().to_string_lossy());
+    }
+}
+
 fn run_once(
     files: &[PathBuf],
     settings: &Settings,
@@ -102,7 +142,7 @@ fn run_once(
 ) -> Result<Vec<Message>> {
     // Collect all the files to check.
     let start = Instant::now();
-    let paths: Vec<DirEntry> = files
+    let paths: Vec<Result<DirEntry, walkdir::Error>> = files
         .iter()
         .flat_map(|path| iter_python_files(path, &settings.exclude, &settings.extend_exclude))
         .collect();
@@ -113,16 +153,33 @@ fn run_once(
     let mut messages: Vec<Message> = paths
         .par_iter()
         .map(|entry| {
-            lint_path(entry.path(), settings, &cache.into(), &autofix.into()).unwrap_or_else(|e| {
-                if settings.select.contains(&CheckCode::E999) {
-                    vec![Message {
-                        kind: CheckKind::SyntaxError(e.to_string()),
-                        fixed: false,
-                        location: Default::default(),
-                        filename: entry.path().to_string_lossy().to_string(),
-                    }]
+            match entry {
+                Ok(entry) => {
+                    let path = entry.path();
+                    lint_path(path, settings, &cache.into(), &autofix.into())
+                        .map_err(|e| (Some(path.to_owned()), e.to_string()))
+                }
+                Err(e) => Err((
+                    e.path().map(Path::to_owned),
+                    e.io_error()
+                        .map_or_else(|| e.to_string(), io::Error::to_string),
+                )),
+            }
+            .unwrap_or_else(|(path, message)| {
+                if let Some(path) = path {
+                    if settings.select.contains(&CheckCode::E902) {
+                        vec![Message {
+                            kind: CheckKind::IOError(message),
+                            fixed: false,
+                            location: Default::default(),
+                            filename: path.to_string_lossy().to_string(),
+                        }]
+                    } else {
+                        error!("Failed to check {}: {message}", path.to_string_lossy());
+                        vec![]
+                    }
                 } else {
-                    error!("Failed to check {}: {e:?}", entry.path().to_string_lossy());
+                    error!("{message}");
                     vec![]
                 }
             })
@@ -130,19 +187,6 @@ fn run_once(
         .flatten()
         .collect();
 
-    if settings.select.contains(&CheckCode::E902) {
-        for file in files {
-            if !file.exists() {
-                messages.push(Message {
-                    kind: CheckKind::IOError(file.to_string_lossy().to_string()),
-                    fixed: false,
-                    location: Default::default(),
-                    filename: file.to_string_lossy().to_string(),
-                })
-            }
-        }
-    }
-
     messages.sort_unstable();
     let duration = start.elapsed();
     debug!("Checked files in: {:?}", duration);
@@ -150,6 +194,35 @@ fn run_once(
     Ok(messages)
 }
 
+fn add_noqa(files: &[PathBuf], settings: &Settings) -> Result<usize> {
+    // Collect all the files to check.
+    let start = Instant::now();
+    let paths: Vec<Result<DirEntry, walkdir::Error>> = files
+        .iter()
+        .flat_map(|path| iter_python_files(path, &settings.exclude, &settings.extend_exclude))
+        .collect();
+    let duration = start.elapsed();
+    debug!("Identified files to lint in: {:?}", duration);
+
+    let start = Instant::now();
+    let modifications: usize = paths
+        .par_iter()
+        .map(|entry| match entry {
+            Ok(entry) => {
+                let path = entry.path();
+                add_noqa_to_path(path, settings)
+            }
+            Err(_) => Ok(0),
+        })
+        .flatten()
+        .sum();
+
+    let duration = start.elapsed();
+    debug!("Added noqa to files in: {:?}", duration);
+
+    Ok(modifications)
+}
+
 fn inner_main() -> Result<ExitCode> {
     let cli = Cli::parse();
 
@@ -168,38 +241,76 @@ fn inner_main() -> Result<ExitCode> {
     };
 
     // Parse the settings from the pyproject.toml and command-line arguments.
-    let mut settings = Settings::from_pyproject(&pyproject, &project_root);
+    let exclude: Vec<FilePattern> = cli
+        .exclude
+        .iter()
+        .map(|path| FilePattern::from_user(path, &project_root))
+        .collect();
+    let extend_exclude: Vec<FilePattern> = cli
+        .extend_exclude
+        .iter()
+        .map(|path| FilePattern::from_user(path, &project_root))
+        .collect();
+    let per_file_ignores: Vec<PerFileIgnore> = cli
+        .per_file_ignores
+        .into_iter()
+        .map(|pair| PerFileIgnore::new(pair, &project_root))
+        .collect();
+
+    let mut settings = Settings::from_pyproject(pyproject, project_root)?;
+    if !exclude.is_empty() {
+        settings.exclude = exclude;
+    }
+    if !extend_exclude.is_empty() {
+        settings.extend_exclude = extend_exclude;
+    }
+    if !per_file_ignores.is_empty() {
+        settings.per_file_ignores = per_file_ignores;
+    }
     if !cli.select.is_empty() {
+        settings.clear();
         settings.select(cli.select);
     }
+    if !cli.extend_select.is_empty() {
+        settings.select(cli.extend_select);
+    }
     if !cli.ignore.is_empty() {
         settings.ignore(&cli.ignore);
     }
-    if !cli.exclude.is_empty() {
-        settings.exclude = cli
-            .exclude
-            .iter()
-            .map(|path| FilePattern::from_user(path, &project_root))
-            .collect();
+    if !cli.extend_ignore.is_empty() {
+        settings.ignore(&cli.extend_ignore);
     }
-    if !cli.extend_exclude.is_empty() {
-        settings.extend_exclude = cli
-            .extend_exclude
-            .iter()
-            .map(|path| FilePattern::from_user(path, &project_root))
-            .collect();
+    if let Some(dummy_variable_rgx) = cli.dummy_variable_rgx {
+        settings.dummy_variable_rgx = dummy_variable_rgx;
+    }
+
+    if cli.show_settings && cli.show_files {
+        eprintln!("Error: specify --show-settings or show-files (not both).");
+        return Ok(ExitCode::FAILURE);
+    }
+    if cli.show_files {
+        show_files(&cli.files, &settings);
+        return Ok(ExitCode::SUCCESS);
+    }
+    if cli.show_settings {
+        show_settings(settings);
+        return Ok(ExitCode::SUCCESS);
     }
 
     cache::init()?;
 
-    let mut printer = Printer::new(cli.format);
+    let mut printer = Printer::new(cli.format, cli.verbose);
     if cli.watch {
         if cli.fix {
-            println!("Warning: --fix is not enabled in watch mode.");
+            eprintln!("Warning: --fix is not enabled in watch mode.");
+        }
+
+        if cli.add_noqa {
+            eprintln!("Warning: --no-qa is not enabled in watch mode.");
         }
 
         if cli.format != SerializationFormat::Text {
-            println!("Warning: --format 'text' is used in watch mode.");
+            eprintln!("Warning: --format 'text' is used in watch mode.");
         }
 
         // Perform an initial run instantly.
@@ -236,6 +347,11 @@ fn inner_main() -> Result<ExitCode> {
                 Err(e) => return Err(e.into()),
             }
         }
+    } else if cli.add_noqa {
+        let modifications = add_noqa(&cli.files, &settings)?;
+        if modifications > 0 {
+            println!("Added {modifications} noqa directives.");
+        }
     } else {
         let messages = run_once(&cli.files, &settings, !cli.no_cache, cli.fix)?;
         if !cli.quiet {
@@ -256,6 +372,9 @@ fn inner_main() -> Result<ExitCode> {
 fn main() -> ExitCode {
     match inner_main() {
         Ok(code) => code,
-        Err(_) => ExitCode::FAILURE,
+        Err(err) => {
+            eprintln!("{} {:?}", "error".red().bold(), err);
+            ExitCode::FAILURE
+        }
     }
 }

src/noqa.rs

@@ -0,0 +1,281 @@
+use std::cmp::{max, min};
+use std::collections::{BTreeMap, BTreeSet};
+use std::fs;
+use std::path::Path;
+
+use anyhow::Result;
+use once_cell::sync::Lazy;
+use regex::Regex;
+use rustpython_parser::lexer::{LexResult, Tok};
+
+use crate::checks::{Check, CheckCode};
+
+static NO_QA_REGEX: Lazy<Regex> = Lazy::new(|| {
+    Regex::new(r"(?i)(?P<noqa>\s*# noqa(?::\s?(?P<codes>([A-Z]+[0-9]+(?:[,\s]+)?)+))?)")
+        .expect("Invalid regex")
+});
+static SPLIT_COMMA_REGEX: Lazy<Regex> = Lazy::new(|| Regex::new(r"[,\s]").expect("Invalid regex"));
+
+#[derive(Debug)]
+pub enum Directive<'a> {
+    None,
+    All(usize),
+    Codes(usize, Vec<&'a str>),
+}
+
+pub fn extract_noqa_directive(line: &str) -> Directive {
+    match NO_QA_REGEX.captures(line) {
+        Some(caps) => match caps.name("noqa") {
+            Some(noqa) => match caps.name("codes") {
+                Some(codes) => Directive::Codes(
+                    noqa.start(),
+                    SPLIT_COMMA_REGEX
+                        .split(codes.as_str())
+                        .map(|code| code.trim())
+                        .filter(|code| !code.is_empty())
+                        .collect(),
+                ),
+                None => Directive::All(noqa.start()),
+            },
+            None => Directive::None,
+        },
+        None => Directive::None,
+    }
+}
+
+pub fn extract_noqa_line_for(lxr: &[LexResult]) -> Vec<usize> {
+    let mut noqa_line_for: Vec<usize> = vec![];
+
+    let mut last_is_string = false;
+    let mut last_seen = usize::MIN;
+    let mut min_line = usize::MAX;
+    let mut max_line = usize::MIN;
+
+    for (start, tok, end) in lxr.iter().flatten() {
+        if matches!(tok, Tok::EndOfFile) {
+            break;
+        }
+
+        if matches!(tok, Tok::Newline) {
+            min_line = min(min_line, start.row());
+            max_line = max(max_line, start.row());
+
+            // For now, we only care about preserving noqa directives across multi-line strings.
+            if last_is_string {
+                noqa_line_for.extend(vec![max_line; (max_line + 1) - min_line]);
+            } else {
+                for i in (min_line - 1)..(max_line) {
+                    noqa_line_for.push(i + 1);
+                }
+            }
+
+            min_line = usize::MAX;
+            max_line = usize::MIN;
+        } else {
+            // Handle empty lines.
+            if start.row() > last_seen {
+                for i in last_seen..(start.row() - 1) {
+                    noqa_line_for.push(i + 1);
+                }
+            }
+
+            min_line = min(min_line, start.row());
+            max_line = max(max_line, end.row());
+        }
+        last_seen = start.row();
+        last_is_string = matches!(tok, Tok::String { .. });
+    }
+
+    noqa_line_for
+}
+
+fn add_noqa_inner(
+    checks: &Vec<Check>,
+    contents: &str,
+    noqa_line_for: &[usize],
+) -> Result<(usize, String)> {
+    let lines: Vec<&str> = contents.lines().collect();
+    let mut matches_by_line: BTreeMap<usize, BTreeSet<&CheckCode>> = BTreeMap::new();
+    for lineno in 0..lines.len() {
+        let mut codes: BTreeSet<&CheckCode> = BTreeSet::new();
+        for check in checks {
+            if check.location.row() == lineno + 1 {
+                codes.insert(check.kind.code());
+            }
+        }
+
+        // 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)
+            .map(|lineno| lineno - 1)
+            .unwrap_or(lineno);
+
+        if !codes.is_empty() {
+            let matches = matches_by_line
+                .entry(noqa_lineno)
+                .or_insert_with(BTreeSet::new);
+            matches.append(&mut codes);
+        }
+    }
+
+    let mut count: usize = 0;
+    let mut output = "".to_string();
+    for (lineno, line) in lines.iter().enumerate() {
+        match matches_by_line.get(&lineno) {
+            None => {
+                output.push_str(line);
+                output.push('\n');
+            }
+            Some(codes) => {
+                match extract_noqa_directive(line) {
+                    Directive::None => {
+                        output.push_str(line);
+                    }
+                    Directive::All(start) => output.push_str(&line[..start]),
+                    Directive::Codes(start, _) => output.push_str(&line[..start]),
+                };
+                let codes: Vec<&str> = codes.iter().map(|code| code.as_str()).collect();
+                output.push_str("  # noqa: ");
+                output.push_str(&codes.join(", "));
+                output.push('\n');
+                count += 1;
+            }
+        }
+    }
+
+    Ok((count, output))
+}
+
+pub fn add_noqa(
+    checks: &Vec<Check>,
+    contents: &str,
+    noqa_line_for: &[usize],
+    path: &Path,
+) -> Result<usize> {
+    let (count, output) = add_noqa_inner(checks, contents, noqa_line_for)?;
+    fs::write(path, output)?;
+    Ok(count)
+}
+
+#[cfg(test)]
+mod tests {
+    use anyhow::Result;
+    use rustpython_parser::ast::Location;
+    use rustpython_parser::lexer;
+    use rustpython_parser::lexer::LexResult;
+
+    use crate::checks::{Check, CheckKind};
+    use crate::noqa::{add_noqa_inner, extract_noqa_line_for};
+
+    #[test]
+    fn extraction() -> Result<()> {
+        let lxr: Vec<LexResult> = lexer::make_tokenizer(
+            "x = 1
+y = 2
+z = x + 1",
+        )
+        .collect();
+        println!("{:?}", extract_noqa_line_for(&lxr));
+        assert_eq!(extract_noqa_line_for(&lxr), vec![1, 2, 3]);
+
+        let lxr: Vec<LexResult> = lexer::make_tokenizer(
+            "
+x = 1
+y = 2
+z = x + 1",
+        )
+        .collect();
+        println!("{:?}", extract_noqa_line_for(&lxr));
+        assert_eq!(extract_noqa_line_for(&lxr), vec![1, 2, 3, 4]);
+
+        let lxr: Vec<LexResult> = lexer::make_tokenizer(
+            "x = 1
+y = 2
+z = x + 1
+        ",
+        )
+        .collect();
+        println!("{:?}", extract_noqa_line_for(&lxr));
+        assert_eq!(extract_noqa_line_for(&lxr), vec![1, 2, 3]);
+
+        let lxr: Vec<LexResult> = lexer::make_tokenizer(
+            "x = 1
+
+y = 2
+z = x + 1
+        ",
+        )
+        .collect();
+        println!("{:?}", extract_noqa_line_for(&lxr));
+        assert_eq!(extract_noqa_line_for(&lxr), vec![1, 2, 3, 4]);
+
+        let lxr: Vec<LexResult> = lexer::make_tokenizer(
+            "x = '''abc
+def
+ghi
+'''
+y = 2
+z = x + 1",
+        )
+        .collect();
+        assert_eq!(extract_noqa_line_for(&lxr), vec![4, 4, 4, 4, 5, 6]);
+
+        Ok(())
+    }
+
+    #[test]
+    fn modification() -> Result<()> {
+        let checks = vec![];
+        let contents = "x = 1";
+        let noqa_line_for = vec![1];
+        let (count, output) = add_noqa_inner(&checks, contents, &noqa_line_for)?;
+        assert_eq!(count, 0);
+        assert_eq!(output.trim(), contents.trim());
+
+        let checks = vec![Check::new(
+            CheckKind::UnusedVariable("x".to_string()),
+            Location::new(1, 1),
+        )];
+        let contents = "x = 1";
+        let noqa_line_for = vec![1];
+        let (count, output) = add_noqa_inner(&checks, contents, &noqa_line_for)?;
+        assert_eq!(count, 1);
+        assert_eq!(output.trim(), "x = 1  # noqa: F841".trim());
+
+        let checks = vec![
+            Check::new(
+                CheckKind::AmbiguousVariableName("x".to_string()),
+                Location::new(1, 1),
+            ),
+            Check::new(
+                CheckKind::UnusedVariable("x".to_string()),
+                Location::new(1, 1),
+            ),
+        ];
+        let contents = "x = 1  # noqa: E741";
+        let noqa_line_for = vec![1];
+        let (count, output) = add_noqa_inner(&checks, contents, &noqa_line_for)?;
+        assert_eq!(count, 1);
+        assert_eq!(output.trim(), "x = 1  # noqa: E741, F841".trim());
+
+        let checks = vec![
+            Check::new(
+                CheckKind::AmbiguousVariableName("x".to_string()),
+                Location::new(1, 1),
+            ),
+            Check::new(
+                CheckKind::UnusedVariable("x".to_string()),
+                Location::new(1, 1),
+            ),
+        ];
+        let contents = "x = 1  # noqa";
+        let noqa_line_for = vec![1];
+        let (count, output) = add_noqa_inner(&checks, contents, &noqa_line_for)?;
+        assert_eq!(count, 1);
+        assert_eq!(output.trim(), "x = 1  # noqa: E741, F841".trim());
+
+        Ok(())
+    }
+}

src/printer.rs

@@ -1,8 +1,10 @@
-use colored::Colorize;
-
 use anyhow::Result;
 use clap::ValueEnum;
+use colored::Colorize;
+use rustpython_parser::ast::Location;
+use serde::Serialize;
 
+use crate::checks::{CheckCode, CheckKind};
 use crate::message::Message;
 use crate::tell_user;
 
@@ -12,13 +14,24 @@ pub enum SerializationFormat {
     Json,
 }
 
+#[derive(Serialize)]
+struct ExpandedMessage<'a> {
+    kind: &'a CheckKind,
+    code: &'a CheckCode,
+    message: String,
+    fixed: bool,
+    location: Location,
+    filename: &'a String,
+}
+
 pub struct Printer {
     format: SerializationFormat,
+    verbose: bool,
 }
 
 impl Printer {
-    pub fn new(format: SerializationFormat) -> Self {
-        Self { format }
+    pub fn new(format: SerializationFormat, verbose: bool) -> Self {
+        Self { format, verbose }
     }
 
     pub fn write_once(&mut self, messages: &[Message]) -> Result<()> {
@@ -31,7 +44,22 @@ impl Printer {
 
         match self.format {
             SerializationFormat::Json => {
-                println!("{}", serde_json::to_string_pretty(&messages)?)
+                println!(
+                    "{}",
+                    serde_json::to_string_pretty(
+                        &messages
+                            .iter()
+                            .map(|m| ExpandedMessage {
+                                kind: &m.kind,
+                                code: m.kind.code(),
+                                message: m.kind.body(),
+                                fixed: m.fixed,
+                                location: m.location,
+                                filename: &m.filename,
+                            })
+                            .collect::<Vec<_>>()
+                    )?
+                )
             }
             SerializationFormat::Text => {
                 if !fixed.is_empty() {
@@ -40,7 +68,7 @@ impl Printer {
                         outstanding.len(),
                         fixed.len()
                     )
-                } else {
+                } else if !outstanding.is_empty() || self.verbose {
                     println!("Found {} error(s).", outstanding.len())
                 }
 

src/pyproject.rs

@@ -1,31 +1,25 @@
-use std::ops::Deref;
 use std::path::{Path, PathBuf};
+use std::str::FromStr;
 
-use anyhow::Result;
+use anyhow::{anyhow, Result};
 use common_path::common_path_all;
-use path_absolutize::path_dedot;
-use serde::Deserialize;
+use path_absolutize::Absolutize;
+use serde::de;
+use serde::{Deserialize, Deserializer};
 
 use crate::checks::CheckCode;
 use crate::fs;
 
-pub fn load_config(pyproject: &Option<PathBuf>) -> Config {
+pub fn load_config(pyproject: &Option<PathBuf>) -> Result<Config> {
     match pyproject {
-        Some(pyproject) => match parse_pyproject_toml(pyproject) {
-            Ok(pyproject) => pyproject
-                .tool
-                .and_then(|tool| tool.ruff)
-                .unwrap_or_default(),
-            Err(e) => {
-                println!("Failed to load pyproject.toml: {:?}", e);
-                println!("Falling back to default configuration...");
-                Default::default()
-            }
-        },
+        Some(pyproject) => Ok(parse_pyproject_toml(pyproject)?
+            .tool
+            .and_then(|tool| tool.ruff)
+            .unwrap_or_default()),
         None => {
-            println!("No pyproject.toml found.");
-            println!("Falling back to default configuration...");
-            Default::default()
+            eprintln!("No pyproject.toml found.");
+            eprintln!("Falling back to default configuration...");
+            Ok(Default::default())
         }
     }
 }
@@ -38,6 +32,50 @@ pub struct Config {
     pub extend_exclude: Option<Vec<String>>,
     pub select: Option<Vec<CheckCode>>,
     pub ignore: Option<Vec<CheckCode>>,
+    pub per_file_ignores: Option<Vec<StrCheckCodePair>>,
+    pub dummy_variable_rgx: Option<String>,
+}
+
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct StrCheckCodePair {
+    pub pattern: String,
+    pub code: CheckCode,
+}
+
+impl StrCheckCodePair {
+    const EXPECTED_PATTERN: &'static str = "<FilePattern>:<CheckCode> pattern";
+}
+
+impl<'de> Deserialize<'de> for StrCheckCodePair {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let str_result = String::deserialize(deserializer)?;
+        Self::from_str(str_result.as_str()).map_err(|_| {
+            de::Error::invalid_value(
+                de::Unexpected::Str(str_result.as_str()),
+                &Self::EXPECTED_PATTERN,
+            )
+        })
+    }
+}
+
+impl FromStr for StrCheckCodePair {
+    type Err = anyhow::Error;
+
+    fn from_str(string: &str) -> Result<Self, Self::Err> {
+        let (pattern_str, code_string) = {
+            let tokens = string.split(':').collect::<Vec<_>>();
+            if tokens.len() != 2 {
+                return Err(anyhow!("Expected {}", Self::EXPECTED_PATTERN));
+            }
+            (tokens[0], tokens[1])
+        };
+        let code = CheckCode::from_str(code_string)?;
+        let pattern = pattern_str.into();
+        Ok(Self { pattern, code })
+    }
 }
 
 #[derive(Debug, PartialEq, Eq, Deserialize)]
@@ -78,8 +116,10 @@ fn find_user_pyproject_toml() -> Option<PathBuf> {
 }
 
 pub fn find_project_root(sources: &[PathBuf]) -> Option<PathBuf> {
-    let cwd = path_dedot::CWD.deref();
-    let absolute_sources: Vec<PathBuf> = sources.iter().map(|source| cwd.join(source)).collect();
+    let absolute_sources: Vec<PathBuf> = sources
+        .iter()
+        .flat_map(|source| source.absolutize().map(|path| path.to_path_buf()))
+        .collect();
     if let Some(prefix) = common_path_all(absolute_sources.iter().map(PathBuf::as_path)) {
         for directory in prefix.ancestors() {
             if directory.join(".git").is_dir() {
@@ -101,9 +141,11 @@ pub fn find_project_root(sources: &[PathBuf]) -> Option<PathBuf> {
 mod tests {
     use std::env::current_dir;
     use std::path::PathBuf;
+    use std::str::FromStr;
 
     use anyhow::Result;
 
+    use super::StrCheckCodePair;
     use crate::checks::CheckCode;
     use crate::pyproject::{
         find_project_root, find_pyproject_toml, parse_pyproject_toml, Config, PyProject, Tools,
@@ -136,6 +178,8 @@ mod tests {
                     extend_exclude: None,
                     select: None,
                     ignore: None,
+                    per_file_ignores: None,
+                    dummy_variable_rgx: None,
                 })
             })
         );
@@ -156,6 +200,8 @@ line-length = 79
                     extend_exclude: None,
                     select: None,
                     ignore: None,
+                    per_file_ignores: None,
+                    dummy_variable_rgx: None,
                 })
             })
         );
@@ -176,6 +222,8 @@ exclude = ["foo.py"]
                     extend_exclude: None,
                     select: None,
                     ignore: None,
+                    per_file_ignores: None,
+                    dummy_variable_rgx: None,
                 })
             })
         );
@@ -196,6 +244,8 @@ select = ["E501"]
                     extend_exclude: None,
                     select: Some(vec![CheckCode::E501]),
                     ignore: None,
+                    per_file_ignores: None,
+                    dummy_variable_rgx: None,
                 })
             })
         );
@@ -216,6 +266,8 @@ ignore = ["E501"]
                     extend_exclude: None,
                     select: None,
                     ignore: Some(vec![CheckCode::E501]),
+                    per_file_ignores: None,
+                    dummy_variable_rgx: None,
                 })
             })
         );
@@ -280,9 +332,29 @@ other-attribute = 1
                 ]),
                 select: None,
                 ignore: None,
+                per_file_ignores: None,
+                dummy_variable_rgx: None,
             }
         );
 
         Ok(())
     }
+
+    #[test]
+    fn str_check_code_pair_strings() {
+        let result = StrCheckCodePair::from_str("foo:E501");
+        assert!(result.is_ok());
+        let result = StrCheckCodePair::from_str("E501:foo");
+        assert!(result.is_err());
+        let result = StrCheckCodePair::from_str("E501");
+        assert!(result.is_err());
+        let result = StrCheckCodePair::from_str("foo");
+        assert!(result.is_err());
+        let result = StrCheckCodePair::from_str("foo:E501:E402");
+        assert!(result.is_err());
+        let result = StrCheckCodePair::from_str("**/bar:E501");
+        assert!(result.is_ok());
+        let result = StrCheckCodePair::from_str("bar:E502");
+        assert!(result.is_err());
+    }
 }

src/python/typing.rs

@@ -1,6 +1,7 @@
-use once_cell::sync::Lazy;
 use std::collections::BTreeSet;
 
+use once_cell::sync::Lazy;
+
 static ANNOTATED_SUBSCRIPTS: Lazy<BTreeSet<&'static str>> = Lazy::new(|| {
     BTreeSet::from([
         "AbstractAsyncContextManager",

src/settings.rs

@@ -2,14 +2,16 @@ use std::collections::BTreeSet;
 use std::hash::{Hash, Hasher};
 use std::path::{Path, PathBuf};
 
+use anyhow::{anyhow, Result};
 use glob::Pattern;
 use once_cell::sync::Lazy;
+use regex::Regex;
 
-use crate::checks::{CheckCode, ALL_CHECK_CODES};
+use crate::checks::{CheckCode, DEFAULT_CHECK_CODES};
 use crate::fs;
-use crate::pyproject::load_config;
+use crate::pyproject::{load_config, StrCheckCodePair};
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, Hash)]
 pub enum FilePattern {
     Simple(&'static str),
     Complex(Pattern, Option<Pattern>),
@@ -34,20 +36,70 @@ impl FilePattern {
     }
 }
 
+#[derive(Debug, Clone, Hash)]
+pub struct PerFileIgnore {
+    pub pattern: FilePattern,
+    pub code: CheckCode,
+}
+
+impl PerFileIgnore {
+    pub fn new(user_in: StrCheckCodePair, project_root: &Option<PathBuf>) -> Self {
+        let pattern = FilePattern::from_user(user_in.pattern.as_str(), project_root);
+        let code = user_in.code;
+        Self { pattern, code }
+    }
+}
+
 #[derive(Debug)]
 pub struct Settings {
+    pub pyproject: Option<PathBuf>,
+    pub project_root: Option<PathBuf>,
     pub line_length: usize,
     pub exclude: Vec<FilePattern>,
     pub extend_exclude: Vec<FilePattern>,
     pub select: BTreeSet<CheckCode>,
+    pub per_file_ignores: Vec<PerFileIgnore>,
+    pub dummy_variable_rgx: Regex,
+}
+
+impl Settings {
+    pub fn for_rule(check_code: CheckCode) -> Self {
+        Self {
+            pyproject: None,
+            project_root: None,
+            line_length: 88,
+            exclude: vec![],
+            extend_exclude: vec![],
+            select: BTreeSet::from([check_code]),
+            per_file_ignores: vec![],
+            dummy_variable_rgx: DEFAULT_DUMMY_VARIABLE_RGX.clone(),
+        }
+    }
+
+    pub fn for_rules(check_codes: Vec<CheckCode>) -> Self {
+        Self {
+            pyproject: None,
+            project_root: None,
+            line_length: 88,
+            exclude: vec![],
+            extend_exclude: vec![],
+            select: BTreeSet::from_iter(check_codes),
+            per_file_ignores: vec![],
+            dummy_variable_rgx: DEFAULT_DUMMY_VARIABLE_RGX.clone(),
+        }
+    }
 }
 
 impl Hash for Settings {
     fn hash<H: Hasher>(&self, state: &mut H) {
         self.line_length.hash(state);
+        self.dummy_variable_rgx.as_str().hash(state);
         for value in self.select.iter() {
             value.hash(state);
         }
+        for value in self.per_file_ignores.iter() {
+            value.hash(state);
+        }
     }
 }
 
@@ -75,9 +127,15 @@ static DEFAULT_EXCLUDE: Lazy<Vec<FilePattern>> = Lazy::new(|| {
     ]
 });
 
+static DEFAULT_DUMMY_VARIABLE_RGX: Lazy<Regex> =
+    Lazy::new(|| Regex::new("^(_+|(_+[a-zA-Z0-9_]*[a-zA-Z0-9]+?))$").unwrap());
+
 impl Settings {
-    pub fn from_pyproject(path: &Option<PathBuf>, project_root: &Option<PathBuf>) -> Self {
-        let config = load_config(path);
+    pub fn from_pyproject(
+        pyproject: Option<PathBuf>,
+        project_root: Option<PathBuf>,
+    ) -> Result<Self> {
+        let config = load_config(&pyproject)?;
         let mut settings = Settings {
             line_length: config.line_length.unwrap_or(88),
             exclude: config
@@ -85,7 +143,7 @@ impl Settings {
                 .map(|paths| {
                     paths
                         .iter()
-                        .map(|path| FilePattern::from_user(path, project_root))
+                        .map(|path| FilePattern::from_user(path, &project_root))
                         .collect()
                 })
                 .unwrap_or_else(|| DEFAULT_EXCLUDE.clone()),
@@ -94,24 +152,43 @@ impl Settings {
                 .map(|paths| {
                     paths
                         .iter()
-                        .map(|path| FilePattern::from_user(path, project_root))
+                        .map(|path| FilePattern::from_user(path, &project_root))
                         .collect()
                 })
                 .unwrap_or_default(),
             select: if let Some(select) = config.select {
                 BTreeSet::from_iter(select)
             } else {
-                BTreeSet::from_iter(ALL_CHECK_CODES)
+                BTreeSet::from_iter(DEFAULT_CHECK_CODES)
             },
+            per_file_ignores: config
+                .per_file_ignores
+                .map(|ignore_strings| {
+                    ignore_strings
+                        .into_iter()
+                        .map(|pair| PerFileIgnore::new(pair, &project_root))
+                        .collect()
+                })
+                .unwrap_or_default(),
+            dummy_variable_rgx: match config.dummy_variable_rgx {
+                Some(pattern) => Regex::new(&pattern)
+                    .map_err(|e| anyhow!("Invalid dummy-variable-rgx value: {e}"))?,
+                None => DEFAULT_DUMMY_VARIABLE_RGX.clone(),
+            },
+            pyproject,
+            project_root,
         };
         if let Some(ignore) = &config.ignore {
             settings.ignore(ignore);
         }
-        settings
+        Ok(settings)
+    }
+
+    pub fn clear(&mut self) {
+        self.select.clear();
     }
 
     pub fn select(&mut self, codes: Vec<CheckCode>) {
-        self.select.clear();
         for code in codes {
             self.select.insert(code);
         }
@@ -123,3 +200,62 @@ impl Settings {
         }
     }
 }
+
+/// Struct to render user-facing exclusion patterns.
+#[derive(Debug)]
+#[allow(dead_code)]
+pub struct Exclusion {
+    basename: Option<String>,
+    absolute: Option<String>,
+}
+
+impl Exclusion {
+    pub fn from_file_pattern(file_pattern: FilePattern) -> Self {
+        match file_pattern {
+            FilePattern::Simple(basename) => Exclusion {
+                basename: Some(basename.to_string()),
+                absolute: None,
+            },
+            FilePattern::Complex(absolute, basename) => Exclusion {
+                basename: basename.map(|pattern| pattern.to_string()),
+                absolute: Some(absolute.to_string()),
+            },
+        }
+    }
+}
+
+/// Struct to render user-facing Settings.
+#[derive(Debug)]
+pub struct CurrentSettings {
+    pub pyproject: Option<PathBuf>,
+    pub project_root: Option<PathBuf>,
+    pub line_length: usize,
+    pub exclude: Vec<Exclusion>,
+    pub extend_exclude: Vec<Exclusion>,
+    pub select: BTreeSet<CheckCode>,
+    pub per_file_ignores: Vec<PerFileIgnore>,
+    pub dummy_variable_rgx: Regex,
+}
+
+impl CurrentSettings {
+    pub fn from_settings(settings: Settings) -> Self {
+        Self {
+            pyproject: settings.pyproject,
+            project_root: settings.project_root,
+            line_length: settings.line_length,
+            exclude: settings
+                .exclude
+                .into_iter()
+                .map(Exclusion::from_file_pattern)
+                .collect(),
+            extend_exclude: settings
+                .extend_exclude
+                .into_iter()
+                .map(Exclusion::from_file_pattern)
+                .collect(),
+            select: settings.select,
+            per_file_ignores: settings.per_file_ignores,
+            dummy_variable_rgx: settings.dummy_variable_rgx,
+        }
+    }
+}

src/snapshots/ruff__linter__tests__a001.snap

@@ -0,0 +1,112 @@
+---
+source: src/linter.rs
+expression: checks
+---
+- kind:
+    BuiltinVariableShadowing: sum
+  location:
+    row: 1
+    column: 1
+  fix: ~
+- kind:
+    BuiltinVariableShadowing: int
+  location:
+    row: 2
+    column: 1
+  fix: ~
+- kind:
+    BuiltinVariableShadowing: print
+  location:
+    row: 4
+    column: 1
+  fix: ~
+- kind:
+    BuiltinVariableShadowing: copyright
+  location:
+    row: 5
+    column: 1
+  fix: ~
+- kind:
+    BuiltinVariableShadowing: complex
+  location:
+    row: 6
+    column: 2
+  fix: ~
+- kind:
+    BuiltinVariableShadowing: float
+  location:
+    row: 7
+    column: 1
+  fix: ~
+- kind:
+    BuiltinVariableShadowing: object
+  location:
+    row: 7
+    column: 9
+  fix: ~
+- kind:
+    BuiltinVariableShadowing: min
+  location:
+    row: 8
+    column: 1
+  fix: ~
+- kind:
+    BuiltinVariableShadowing: max
+  location:
+    row: 8
+    column: 6
+  fix: ~
+- kind:
+    BuiltinVariableShadowing: bytes
+  location:
+    row: 10
+    column: 1
+  fix: ~
+- kind:
+    BuiltinVariableShadowing: slice
+  location:
+    row: 13
+    column: 1
+  fix: ~
+- kind:
+    BuiltinVariableShadowing: ValueError
+  location:
+    row: 18
+    column: 1
+  fix: ~
+- kind:
+    BuiltinVariableShadowing: memoryview
+  location:
+    row: 21
+    column: 5
+  fix: ~
+- kind:
+    BuiltinVariableShadowing: bytearray
+  location:
+    row: 21
+    column: 18
+  fix: ~
+- kind:
+    BuiltinVariableShadowing: str
+  location:
+    row: 24
+    column: 22
+  fix: ~
+- kind:
+    BuiltinVariableShadowing: all
+  location:
+    row: 24
+    column: 45
+  fix: ~
+- kind:
+    BuiltinVariableShadowing: any
+  location:
+    row: 24
+    column: 50
+  fix: ~
+- kind:
+    BuiltinVariableShadowing: sum
+  location:
+    row: 27
+    column: 8
+  fix: ~

src/snapshots/ruff__linter__tests__a002.snap

@@ -0,0 +1,46 @@
+---
+source: src/linter.rs
+expression: checks
+---
+- kind:
+    BuiltinArgumentShadowing: str
+  location:
+    row: 1
+    column: 11
+  fix: ~
+- kind:
+    BuiltinArgumentShadowing: type
+  location:
+    row: 1
+    column: 19
+  fix: ~
+- kind:
+    BuiltinArgumentShadowing: complex
+  location:
+    row: 1
+    column: 26
+  fix: ~
+- kind:
+    BuiltinArgumentShadowing: Exception
+  location:
+    row: 1
+    column: 35
+  fix: ~
+- kind:
+    BuiltinArgumentShadowing: getattr
+  location:
+    row: 1
+    column: 48
+  fix: ~
+- kind:
+    BuiltinArgumentShadowing: bytes
+  location:
+    row: 5
+    column: 17
+  fix: ~
+- kind:
+    BuiltinArgumentShadowing: float
+  location:
+    row: 9
+    column: 16
+  fix: ~

src/snapshots/ruff__linter__tests__a003.snap

@@ -0,0 +1,18 @@
+---
+source: src/linter.rs
+assertion_line: 762
+expression: checks
+---
+- kind:
+    BuiltinAttributeShadowing: ImportError
+  location:
+    row: 2
+    column: 5
+  fix: ~
+- kind:
+    BuiltinAttributeShadowing: str
+  location:
+    row: 7
+    column: 5
+  fix: ~
+

src/snapshots/ruff__linter__tests__e999.snap

@@ -0,0 +1,11 @@
+---
+source: src/linter.rs
+expression: checks
+---
+- kind:
+    SyntaxError: Got unexpected EOF
+  location:
+    row: 2
+    column: 1
+  fix: ~
+

src/snapshots/ruff__linter__tests__f402.snap

@@ -0,0 +1,21 @@
+---
+source: src/linter.rs
+expression: checks
+---
+- kind:
+    ImportShadowedByLoopVar:
+      - os
+      - 1
+  location:
+    row: 5
+    column: 5
+  fix: ~
+- kind:
+    ImportShadowedByLoopVar:
+      - path
+      - 2
+  location:
+    row: 8
+    column: 5
+  fix: ~
+

src/snapshots/ruff__linter__tests__f403.snap

@@ -3,13 +3,13 @@ source: src/linter.rs
 expression: checks
 ---
 - kind:
-    ImportStarUsage: F634
+    ImportStarUsed: F634
   location:
     row: 1
     column: 1
   fix: ~
 - kind:
-    ImportStarUsage: F634
+    ImportStarUsed: F634
   location:
     row: 2
     column: 1

src/snapshots/ruff__linter__tests__f405.snap

@@ -0,0 +1,21 @@
+---
+source: src/linter.rs
+expression: checks
+---
+- kind:
+    ImportStarUsage:
+      - name
+      - mymodule
+  location:
+    row: 5
+    column: 11
+  fix: ~
+- kind:
+    ImportStarUsage:
+      - a
+      - mymodule
+  location:
+    row: 11
+    column: 1
+  fix: ~
+

src/snapshots/ruff__linter__tests__f821.snap

@@ -38,4 +38,16 @@ expression: checks
     row: 83
     column: 11
   fix: ~
+- kind:
+    UndefinedName: B
+  location:
+    row: 87
+    column: 7
+  fix: ~
+- kind:
+    UndefinedName: B
+  location:
+    row: 89
+    column: 7
+  fix: ~
 

src/snapshots/ruff__linter__tests__f841_dummy_variable_rgx.snap

@@ -0,0 +1,47 @@
+---
+source: src/linter.rs
+expression: checks
+---
+- kind:
+    UnusedVariable: e
+  location:
+    row: 3
+    column: 1
+  fix: ~
+- kind:
+    UnusedVariable: foo
+  location:
+    row: 20
+    column: 5
+  fix: ~
+- kind:
+    UnusedVariable: a
+  location:
+    row: 21
+    column: 6
+  fix: ~
+- kind:
+    UnusedVariable: b
+  location:
+    row: 21
+    column: 9
+  fix: ~
+- kind:
+    UnusedVariable: _
+  location:
+    row: 35
+    column: 5
+  fix: ~
+- kind:
+    UnusedVariable: __
+  location:
+    row: 36
+    column: 5
+  fix: ~
+- kind:
+    UnusedVariable: _discarded
+  location:
+    row: 37
+    column: 5
+  fix: ~
+

src/snapshots/ruff__linter__tests__m001.snap

@@ -0,0 +1,89 @@
+---
+source: src/linter.rs
+expression: checks
+---
+- kind:
+    UnusedNOQA: ~
+  location:
+    row: 9
+    column: 10
+  fix:
+    content: ""
+    start:
+      row: 9
+      column: 10
+    end:
+      row: 9
+      column: 18
+    applied: false
+- kind:
+    UnusedNOQA: E501
+  location:
+    row: 13
+    column: 10
+  fix:
+    content: ""
+    start:
+      row: 13
+      column: 10
+    end:
+      row: 13
+      column: 24
+    applied: false
+- kind:
+    UnusedNOQA: E501
+  location:
+    row: 16
+    column: 10
+  fix:
+    content: "  # noqa: F841"
+    start:
+      row: 16
+      column: 10
+    end:
+      row: 16
+      column: 30
+    applied: false
+- kind:
+    UnusedNOQA: F841
+  location:
+    row: 41
+    column: 4
+  fix:
+    content: "  # noqa: E501"
+    start:
+      row: 41
+      column: 4
+    end:
+      row: 41
+      column: 24
+    applied: false
+- kind:
+    UnusedNOQA: E501
+  location:
+    row: 49
+    column: 4
+  fix:
+    content: ""
+    start:
+      row: 49
+      column: 4
+    end:
+      row: 49
+      column: 18
+    applied: false
+- kind:
+    UnusedNOQA: ~
+  location:
+    row: 57
+    column: 4
+  fix:
+    content: ""
+    start:
+      row: 57
+      column: 4
+    end:
+      row: 57
+      column: 12
+    applied: false
+