Bump version to 0.0.87

.pre-commit-config.yaml

@@ -1,8 +1,8 @@
 repos:
   - repo: https://github.com/charliermarsh/ruff-pre-commit
-    rev: v0.0.40
+    rev: v0.0.87
     hooks:
-      - id: lint
+      - id: ruff
 
   - repo: https://github.com/abravalheri/validate-pyproject
     rev: v0.10.1

Cargo.lock

@@ -466,6 +466,15 @@ dependencies = [
  "winapi 0.3.9",
 ]
 
+[[package]]
+name = "codegen"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ff61280aed771c3070e7dcc9e050c66f1eb1e3b96431ba66f9f74641d02fc41d"
+dependencies = [
+ "indexmap",
+]
+
 [[package]]
 name = "codespan-reporting"
 version = "0.11.1"
@@ -2045,7 +2054,7 @@ dependencies = [
 
 [[package]]
 name = "ruff"
-version = "0.0.84"
+version = "0.0.87"
 dependencies = [
  "anyhow",
  "assert_cmd",
@@ -2054,6 +2063,7 @@ dependencies = [
  "chrono",
  "clap",
  "clearscreen",
+ "codegen",
  "colored",
  "common-path",
  "dirs 4.0.0",

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ruff"
-version = "0.0.84"
+version = "0.0.87"
 edition = "2021"
 
 [lib]
@@ -50,6 +50,7 @@ getrandom = { version = "0.2.7", features = ["js"] }
 
 [dev-dependencies]
 assert_cmd = { version = "2.0.4" }
+codegen = { version = "0.2.0" }
 insta = { version = "1.19.1", features = ["yaml"] }
 test-case = { version = "2.2.2" }
 

README.md

@@ -77,11 +77,14 @@ Ruff also works with [pre-commit](https://pre-commit.com):
 ```yaml
 repos:
   - repo: https://github.com/charliermarsh/ruff-pre-commit
-    rev: v0.0.84
+    rev: v0.0.87
     hooks:
-      - id: lint
+      - id: ruff
 ```
 
+<!-- TODO(charlie): Remove this message a few versions after v0.0.86. -->
+_Note: prior to `v0.0.86`, `ruff-pre-commit` used `lint` (rather than `ruff`) as the hook ID._
+
 ## Configuration
 
 Ruff is configurable both via `pyproject.toml` and the command line.
@@ -95,9 +98,23 @@ select = [
     "F401",
     "F403",
 ]
+per-file-ignores = [
+    "__init__.py:F401",
+    "path/to/file.py:F401"
+]
 ```
 
-Alternatively, on the command-line:
+Plugin configurations should be expressed as subsections, e.g.:
+
+```toml
+[tool.ruff]
+line-length = 88
+
+[tool.ruff.flake8-quotes]
+docstring-quotes = "double"
+```
+
+Alternatively, common configuration settings can be provided via the command-line:
 
 ```shell
 ruff path/to/code/ --select F401 --select F403
@@ -257,7 +274,7 @@ The 🛠 emoji indicates that a rule is automatically fixable by the `--fix` com
 | F841 | UnusedVariable | Local variable `...` is assigned to but never used |  |
 | F901 | RaiseNotImplemented | `raise NotImplemented` should be `raise NotImplementedError` |  |
 
-### pycodestyle
+### pycodestyle (error)
 
 | Code | Name | Message | Fix |
 | ---- | ---- | ------- | --- |
@@ -275,7 +292,13 @@ The 🛠 emoji indicates that a rule is automatically fixable by the `--fix` com
 | E743 | AmbiguousFunctionName | Ambiguous function name: `...` |  |
 | E902 | IOError | IOError: `...` |  |
 | E999 | SyntaxError | SyntaxError: `...` |  |
+
+### pycodestyle (warning)
+
+| Code | Name | Message | Fix |
+| ---- | ---- | ------- | --- |
 | W292 | NoNewLineAtEndOfFile | No newline at end of file |  |
+| W605 | InvalidEscapeSequence | Invalid escape sequence: '\c' |  |
 
 ### pydocstyle
 
@@ -402,6 +425,15 @@ The 🛠 emoji indicates that a rule is automatically fixable by the `--fix` com
 | T201 | PrintFound | `print` found | 🛠 |
 | T203 | PPrintFound | `pprint` found | 🛠 |
 
+### flake8-quotes
+
+| Code | Name | Message | Fix |
+| ---- | ---- | ------- | --- |
+| Q000 | BadQuotesInlineString | Single quotes found but double quotes preferred |  |
+| Q001 | BadQuotesMultilineString | Single quote multiline found but double quotes preferred |  |
+| Q002 | BadQuotesDocstring | Single quote docstring found but double quotes preferred |  |
+| Q003 | AvoidQuoteEscape | Change outer quotes to avoid escaping inner quotes |  |
+
 ### Meta rules
 
 | Code | Name | Message | Fix |
@@ -473,6 +505,7 @@ including:
 - [`flake8-builtins`](https://pypi.org/project/flake8-builtins/)
 - [`flake8-super`](https://pypi.org/project/flake8-super/)
 - [`flake8-print`](https://pypi.org/project/flake8-print/)
+- [`flake8-quotes`](https://pypi.org/project/flake8-quotes/)
 - [`flake8-comprehensions`](https://pypi.org/project/flake8-comprehensions/)
 - [`flake8-bugbear`](https://pypi.org/project/flake8-bugbear/) (9/32)
 - [`pyupgrade`](https://pypi.org/project/pyupgrade/) (8/34)
@@ -493,6 +526,7 @@ Today, Ruff can be used to replace Flake8 when used with any of the following pl
 - [`flake8-builtins`](https://pypi.org/project/flake8-builtins/)
 - [`flake8-super`](https://pypi.org/project/flake8-super/)
 - [`flake8-print`](https://pypi.org/project/flake8-print/)
+- [`flake8-quotes`](https://pypi.org/project/flake8-quotes/)
 - [`flake8-comprehensions`](https://pypi.org/project/flake8-comprehensions/)
 - [`flake8-bugbear`](https://pypi.org/project/flake8-bugbear/) (9/32)
 

examples/generate_check_code_prefix.rs

@@ -0,0 +1,105 @@
+//! Generate the CheckCodePrefix enum.
+
+use std::collections::{BTreeMap, BTreeSet};
+
+use codegen::{Scope, Type, Variant};
+use itertools::Itertools;
+use strum::IntoEnumIterator;
+
+use ruff::checks::CheckCode;
+
+fn main() {
+    // Build up a map from prefix to matching CheckCodes.
+    let mut prefix_to_codes: BTreeMap<String, BTreeSet<CheckCode>> = Default::default();
+    for check_code in CheckCode::iter() {
+        let as_ref = check_code.as_ref().to_string();
+        for i in 1..=as_ref.len() {
+            let prefix = as_ref[..i].to_string();
+            let entry = prefix_to_codes
+                .entry(prefix)
+                .or_insert_with(|| Default::default());
+            entry.insert(check_code.clone());
+        }
+    }
+
+    let mut scope = Scope::new();
+
+    // Create the `CheckCodePrefix` definition.
+    let mut gen = scope
+        .new_enum("CheckCodePrefix")
+        .vis("pub")
+        .derive("EnumString")
+        .derive("Debug")
+        .derive("PartialEq")
+        .derive("Eq")
+        .derive("Clone")
+        .derive("Serialize")
+        .derive("Deserialize");
+    for (prefix, _) in &prefix_to_codes {
+        gen = gen.push_variant(Variant::new(prefix.to_string()));
+    }
+
+    // Create the `PrefixSpecificity` definition.
+    scope
+        .new_enum("PrefixSpecificity")
+        .vis("pub")
+        .derive("PartialEq")
+        .derive("Eq")
+        .derive("PartialOrd")
+        .derive("Ord")
+        .push_variant(Variant::new("Category"))
+        .push_variant(Variant::new("Hundreds"))
+        .push_variant(Variant::new("Tens"))
+        .push_variant(Variant::new("Explicit"));
+
+    // Create the `match` statement, to map from definition to relevant codes.
+    let mut gen = scope
+        .new_impl("CheckCodePrefix")
+        .new_fn("codes")
+        .arg_ref_self()
+        .ret(Type::new("Vec<CheckCode>"))
+        .vis("pub")
+        .line("match self {");
+    for (prefix, codes) in &prefix_to_codes {
+        gen = gen.line(format!(
+            "CheckCodePrefix::{prefix} => vec![{}],",
+            codes
+                .iter()
+                .map(|code| format!("CheckCode::{}", code.as_ref()))
+                .join(", ")
+        ));
+    }
+    gen.line("}");
+
+    // Create the `match` statement, to map from definition to specificity.
+    let mut gen = scope
+        .new_impl("CheckCodePrefix")
+        .new_fn("specificity")
+        .arg_ref_self()
+        .ret(Type::new("PrefixSpecificity"))
+        .vis("pub")
+        .line("match self {");
+    for (prefix, _) in &prefix_to_codes {
+        let specificity = match prefix.len() {
+            4 => "Explicit",
+            3 => "Tens",
+            2 => "Hundreds",
+            1 => "Category",
+            _ => panic!("Invalid prefix: {}", prefix),
+        };
+        gen = gen.line(format!(
+            "CheckCodePrefix::{prefix} => PrefixSpecificity::{},",
+            specificity
+        ));
+    }
+    gen.line("}");
+
+    println!("//! File automatically generated by examples/generate_check_code_prefix.rs.");
+    println!();
+    println!("use serde::{{Deserialize, Serialize}};");
+    println!("use strum_macros::EnumString;");
+    println!();
+    println!("use crate::checks::CheckCode;");
+    println!();
+    println!("{}", scope.to_string());
+}

resources/test/fixtures/F401_5.py

@@ -0,0 +1,5 @@
+"""Test: removal of multi-segment and aliases imports."""
+from a.b import c
+from d.e import f as g
+import h.i
+import j.k as l

resources/test/fixtures/W605.py

@@ -0,0 +1,35 @@
+#: W605:1:10
+regex = '\.png$'
+
+#: W605:2:1
+regex = '''
+\.png$
+'''
+
+#: W605:2:6
+f(
+    '\_'
+)
+
+#: W605:4:6
+"""
+multi-line
+literal
+with \_ somewhere
+in the middle
+"""
+
+#: Okay
+regex = r'\.png$'
+regex = '\\.png$'
+regex = r'''
+\.png$
+'''
+regex = r'''
+\\.png$
+'''
+s = '\\'
+regex = '\w'  # noqa
+regex = '''
+\w
+'''  # noqa

resources/test/fixtures/__init__.py

@@ -1,3 +1,5 @@
+import os
+
 print(__path__)
 
 __all__ = ["a", "b", "c"]

resources/test/fixtures/flake8_quotes/docstring_doubles.py

@@ -0,0 +1,38 @@
+"""
+Double quotes multiline module docstring
+"""
+
+"""
+this is not a docstring
+"""
+
+l = []
+
+class Cls:
+    """
+    Double quotes multiline class docstring
+    """
+
+    """
+    this is not a docstring
+    """
+
+    # The colon in the list indexing below is an edge case for the docstring scanner
+    def f(self, bar="""
+        definitely not a docstring""",
+        val=l[Cls():3]):
+        """
+        Double quotes multiline function docstring
+        """
+
+        some_expression = 'hello world'
+
+        """
+        this is not a docstring
+        """
+
+        if l:
+            """
+            Looks like a docstring, but in reality it isn't - only modules, classes and functions
+            """
+            pass

resources/test/fixtures/flake8_quotes/docstring_doubles_class.py

@@ -0,0 +1,9 @@
+class SingleLineDocstrings():
+    """ Double quotes single line class docstring """
+    """ Not a docstring """
+
+    def foo(self, bar="""not a docstring"""):
+        """ Double quotes single line method docstring"""
+        pass
+
+    class Nested(foo()[:]): """ inline docstring """; pass

resources/test/fixtures/flake8_quotes/docstring_doubles_function.py

@@ -0,0 +1,22 @@
+def foo():
+    """function without params, single line docstring"""
+    """ not a docstring"""
+    return
+
+
+def foo2():
+    """
+        function without params, multiline docstring
+    """
+    """ not a docstring"""
+    return
+
+
+def fun_with_params_no_docstring(a, b="""
+    not a
+""" """docstring"""):
+    pass
+
+def fun_with_params_no_docstring2(a, b=c[foo():], c=\
+    """ not a docstring """):
+    pass

resources/test/fixtures/flake8_quotes/docstring_doubles_module_multiline.py

@@ -0,0 +1,11 @@
+"""
+Double quotes multiline module docstring
+"""
+"""
+this is not a docstring
+"""
+def foo():
+    pass
+"""
+this is not a docstring
+"""

resources/test/fixtures/flake8_quotes/docstring_doubles_module_singleline.py

@@ -0,0 +1,6 @@
+""" Double quotes singleline module docstring """
+""" this is not a docstring """
+
+def foo():
+    pass
+""" this is not a docstring """

resources/test/fixtures/flake8_quotes/docstring_singles.py

@@ -0,0 +1,40 @@
+'''
+Single quotes multiline module docstring
+'''
+
+'''
+this is not a docstring
+'''
+
+l = []
+
+class Cls(MakeKlass('''
+    class params \t not a docstring
+''')):
+    '''
+    Single quotes multiline class docstring
+    '''
+
+    '''
+    this is not a docstring
+    '''
+
+    # The colon in the list indexing below is an edge case for the docstring scanner
+    def f(self, bar='''
+        definitely not a docstring''',
+        val=l[Cls():3]):
+        '''
+        Single quotes multiline function docstring
+        '''
+
+        some_expression = 'hello world'
+
+        '''
+        this is not a docstring
+        '''
+
+        if l:
+            '''
+            Looks like a docstring, but in reality it isn't - only modules, classes and functions
+            '''
+            pass

resources/test/fixtures/flake8_quotes/docstring_singles_class.py

@@ -0,0 +1,9 @@
+class SingleLineDocstrings():
+    ''' Double quotes single line class docstring '''
+    ''' Not a docstring '''
+
+    def foo(self, bar='''not a docstring'''):
+        ''' Double quotes single line method docstring'''
+        pass
+
+    class Nested(foo()[:]): ''' inline docstring '''; pass

resources/test/fixtures/flake8_quotes/docstring_singles_function.py

@@ -0,0 +1,23 @@
+def foo():
+    '''function without params, single line docstring'''
+    ''' not a docstring'''
+    return
+
+
+def foo2():
+    '''
+        function without params, multiline docstring
+    '''
+    ''' not a docstring'''
+    return
+
+
+def fun_with_params_no_docstring(a, b='''
+    not a 
+''' '''docstring'''):
+    pass
+
+def fun_with_params_no_docstring2(a, b=c[foo():], c=\
+    ''' not a docstring '''):
+    pass
+

resources/test/fixtures/flake8_quotes/docstring_singles_module_multiline.py

@@ -0,0 +1,11 @@
+'''
+Double quotes multiline module docstring
+'''
+'''
+this is not a docstring
+'''
+def foo():
+    pass
+'''
+this is not a docstring
+'''

resources/test/fixtures/flake8_quotes/docstring_singles_module_singleline.py

@@ -0,0 +1,6 @@
+''' Double quotes singleline module docstring '''
+''' this is not a docstring '''
+
+def foo():
+    pass
+''' this is not a docstring '''

resources/test/fixtures/flake8_quotes/doubles.py

@@ -0,0 +1,2 @@
+this_should_be_linted = "double quote string"
+this_should_be_linted = u"double quote string"

resources/test/fixtures/flake8_quotes/doubles_escaped.py

@@ -0,0 +1,5 @@
+this_should_raise_Q003 = 'This is a \'string\''
+this_is_fine = '"This" is a \'string\''
+this_is_fine = "This is a 'string'"
+this_is_fine = "\"This\" is a 'string'"
+this_is_fine = r'This is a \'string\''

resources/test/fixtures/flake8_quotes/doubles_multiline_string.py

@@ -0,0 +1,9 @@
+s = """ This "should"
+be
+"linted" """
+
+s = ''' This "should"
+"not" be
+"linted" '''
+
+s = """'This should not be linted due to having would-be quadruple end quote'"""

resources/test/fixtures/flake8_quotes/doubles_noqa.py

@@ -0,0 +1 @@
+this_should_not_be_linted = "double quote string"  # noqa

resources/test/fixtures/flake8_quotes/doubles_wrapped.py

@@ -0,0 +1,2 @@
+s = 'double "quotes" wrapped in singles are ignored'
+s = "single 'quotes' wrapped in doubles are ignored"

resources/test/fixtures/flake8_quotes/singles.py

@@ -0,0 +1,2 @@
+this_should_be_linted = 'single quote string'
+this_should_be_linted = u'double quote string'

resources/test/fixtures/flake8_quotes/singles_escaped.py

@@ -0,0 +1,5 @@
+this_should_raise_Q003 = "This is a \"string\""
+this_is_fine = "'This' is a \"string\""
+this_is_fine = 'This is a "string"'
+this_is_fine = '\'This\' is a "string"'
+this_is_fine = r"This is a \"string\""

resources/test/fixtures/flake8_quotes/singles_multiline_string.py

@@ -0,0 +1,9 @@
+s = ''' This 'should'
+be
+'linted' '''
+
+s = """ This 'should'
+'not' be
+'linted' """
+
+s = '''"This should not be linted due to having would-be quadruple end quote"'''

resources/test/fixtures/flake8_quotes/singles_noqa.py

@@ -0,0 +1 @@
+this_should_not_be_linted = 'single quote string'  # noqa

resources/test/fixtures/flake8_quotes/singles_wrapped.py

@@ -0,0 +1,2 @@
+s = "single 'quotes' wrapped in doubles are ignored"
+s = 'double "quotes" wrapped in singles are ignored'

resources/test/fixtures/pyproject.toml

@@ -5,3 +5,12 @@ extend-exclude = [
     "migrations",
     "directory/also_excluded.py",
 ]
+per-file-ignores = [
+    "__init__.py:F401",
+]
+
+[tool.ruff.flake8-quotes]
+inline-quotes = "single"
+multiline-quotes = "double"
+docstring-quotes = "double"
+avoid-escape = true

src/check_ast.rs

@@ -1,3 +1,5 @@
+//! Lint rules based on AST traversal.
+
 use std::collections::{BTreeMap, BTreeSet};
 use std::ops::Deref;
 use std::path::Path;
@@ -24,7 +26,8 @@ use crate::checks::{Check, CheckCode, CheckKind};
 use crate::docstrings::definition::{Definition, DefinitionKind, Documentable};
 use crate::python::builtins::{BUILTINS, MAGIC_GLOBALS};
 use crate::python::future::ALL_FEATURE_NAMES;
-use crate::settings::{PythonVersion, Settings};
+use crate::settings::types::PythonVersion;
+use crate::settings::Settings;
 use crate::visibility::{module_visibility, transition_scope, Modifier, Visibility, VisibleScope};
 use crate::{
     docstrings, flake8_bugbear, flake8_builtins, flake8_comprehensions, flake8_print, pep8_naming,
@@ -2113,15 +2116,27 @@ impl<'a> Checker<'a> {
                         None
                     };
 
-                    let mut check = Check::new(
-                        CheckKind::UnusedImport(full_names.into_iter().map(String::from).collect()),
-                        self.locate_check(Range::from_located(child)),
-                    );
-                    if let Some(fix) = fix {
-                        check.amend(fix);
+                    if self.path.ends_with("__init__.py") {
+                        self.checks.push(Check::new(
+                            CheckKind::UnusedImport(
+                                full_names.into_iter().map(String::from).collect(),
+                                true,
+                            ),
+                            self.locate_check(Range::from_located(child)),
+                        ));
+                    } else {
+                        let mut check = Check::new(
+                            CheckKind::UnusedImport(
+                                full_names.into_iter().map(String::from).collect(),
+                                false,
+                            ),
+                            self.locate_check(Range::from_located(child)),
+                        );
+                        if let Some(fix) = fix {
+                            check.amend(fix);
+                        }
+                        self.checks.push(check);
                     }
-
-                    self.checks.push(check);
                 }
             }
         }

src/check_lines.rs

@@ -1,3 +1,5 @@
+//! Lint rules based on checking raw physical lines.
+
 use std::collections::BTreeMap;
 
 use rustpython_parser::ast::Location;
@@ -227,7 +229,7 @@ pub fn check_lines(
 mod tests {
     use crate::autofix::fixer;
     use crate::checks::{Check, CheckCode};
-    use crate::settings;
+    use crate::settings::Settings;
 
     use super::check_lines;
 
@@ -241,9 +243,9 @@ mod tests {
                 &mut checks,
                 line,
                 &noqa_line_for,
-                &settings::Settings {
+                &Settings {
                     line_length,
-                    ..settings::Settings::for_rule(CheckCode::E501)
+                    ..Settings::for_rule(CheckCode::E501)
                 },
                 &fixer::Mode::Generate,
             );

src/check_tokens.rs

@@ -0,0 +1,54 @@
+//! Lint rules based on token traversal.
+
+use rustpython_parser::lexer::{LexResult, Tok};
+
+use crate::ast::operations::SourceCodeLocator;
+use crate::checks::{Check, CheckCode};
+use crate::flake8_quotes::docstring_detection::StateMachine;
+use crate::{flake8_quotes, pycodestyle, Settings};
+
+pub fn check_tokens(
+    checks: &mut Vec<Check>,
+    contents: &str,
+    tokens: &[LexResult],
+    settings: &Settings,
+) {
+    let enforce_invalid_escape_sequence = settings.enabled.contains(&CheckCode::W605);
+    let enforce_quotes = settings.enabled.contains(&CheckCode::Q000)
+        | settings.enabled.contains(&CheckCode::Q001)
+        | settings.enabled.contains(&CheckCode::Q002)
+        | settings.enabled.contains(&CheckCode::Q003);
+
+    // TODO(charlie): Use a shared SourceCodeLocator between this site and the AST traversal.
+    let locator = SourceCodeLocator::new(contents);
+
+    let mut state_machine = StateMachine::new();
+    for (start, tok, end) in tokens.iter().flatten() {
+        // W605
+        if enforce_invalid_escape_sequence {
+            if matches!(tok, Tok::String { .. }) {
+                checks.extend(pycodestyle::checks::invalid_escape_sequence(
+                    &locator, start, end,
+                ));
+            }
+        }
+
+        // flake8-quotes
+        if enforce_quotes {
+            let is_docstring = state_machine.consume(tok);
+            if matches!(tok, Tok::String { .. }) {
+                if let Some(check) = flake8_quotes::checks::quotes(
+                    &locator,
+                    start,
+                    end,
+                    is_docstring,
+                    &settings.flake8_quotes,
+                ) {
+                    if settings.enabled.contains(check.kind.code()) {
+                        checks.push(check);
+                    }
+                }
+            }
+        }
+    }
+}

src/checks.rs

@@ -7,6 +7,7 @@ use strum_macros::{AsRefStr, EnumIter, EnumString};
 
 use crate::ast::types::Range;
 use crate::autofix::Fix;
+use crate::flake8_quotes::settings::Quote;
 use crate::pyupgrade::types::Primitive;
 
 #[derive(
@@ -41,6 +42,7 @@ pub enum CheckCode {
     E999,
     // pycodestyle warnings
     W292,
+    W605,
     // pyflakes
     F401,
     F402,
@@ -101,6 +103,11 @@ pub enum CheckCode {
     // flake8-print
     T201,
     T203,
+    // flake8-quotes
+    Q000,
+    Q001,
+    Q002,
+    Q003,
     // pyupgrade
     U001,
     U002,
@@ -174,7 +181,8 @@ pub enum CheckCode {
 #[derive(EnumIter, Debug, PartialEq, Eq)]
 pub enum CheckCategory {
     Pyflakes,
-    Pycodestyle,
+    PycodestyleError,
+    PycodestyleWarning,
     Pydocstyle,
     Pyupgrade,
     PEP8Naming,
@@ -182,18 +190,21 @@ pub enum CheckCategory {
     Flake8Bugbear,
     Flake8Builtins,
     Flake8Print,
+    Flake8Quotes,
     Meta,
 }
 
 impl CheckCategory {
     pub fn title(&self) -> &'static str {
         match self {
-            CheckCategory::Pycodestyle => "pycodestyle",
+            CheckCategory::PycodestyleError => "pycodestyle (error)",
+            CheckCategory::PycodestyleWarning => "pycodestyle (warning)",
             CheckCategory::Pyflakes => "Pyflakes",
             CheckCategory::Flake8Builtins => "flake8-builtins",
             CheckCategory::Flake8Bugbear => "flake8-bugbear",
             CheckCategory::Flake8Comprehensions => "flake8-comprehensions",
             CheckCategory::Flake8Print => "flake8-print",
+            CheckCategory::Flake8Quotes => "flake8-quotes",
             CheckCategory::Pyupgrade => "pyupgrade",
             CheckCategory::Pydocstyle => "pydocstyle",
             CheckCategory::PEP8Naming => "pep8-naming",
@@ -205,8 +216,9 @@ impl CheckCategory {
 #[allow(clippy::upper_case_acronyms)]
 pub enum LintSource {
     AST,
-    Lines,
     FileSystem,
+    Lines,
+    Tokens,
 }
 
 #[derive(Debug, PartialEq, Eq, Serialize, Deserialize)]
@@ -234,6 +246,7 @@ pub enum CheckKind {
     TypeComparison,
     // pycodestyle warnings
     NoNewLineAtEndOfFile,
+    InvalidEscapeSequence(char),
     // pyflakes
     AssertTuple,
     BreakOutsideLoop,
@@ -260,7 +273,7 @@ pub enum CheckKind {
     UndefinedExport(String),
     UndefinedLocal(String),
     UndefinedName(String),
-    UnusedImport(Vec<String>),
+    UnusedImport(Vec<String>, bool),
     UnusedVariable(String),
     YieldOutsideFunction,
     // flake8-builtins
@@ -294,6 +307,11 @@ pub enum CheckKind {
     // flake8-print
     PrintFound,
     PPrintFound,
+    // flake8-quotes
+    BadQuotesInlineString(Quote),
+    BadQuotesMultilineString(Quote),
+    BadQuotesDocstring(Quote),
+    AvoidQuoteEscape,
     // pyupgrade
     TypeOfPrimitive(Primitive),
     UnnecessaryAbspath,
@@ -369,6 +387,11 @@ impl CheckCode {
     pub fn lint_source(&self) -> &'static LintSource {
         match self {
             CheckCode::E501 | CheckCode::W292 | CheckCode::M001 => &LintSource::Lines,
+            CheckCode::W605
+            | CheckCode::Q000
+            | CheckCode::Q001
+            | CheckCode::Q002
+            | CheckCode::Q003 => &LintSource::Tokens,
             CheckCode::E902 => &LintSource::FileSystem,
             _ => &LintSource::AST,
         }
@@ -394,8 +417,9 @@ impl CheckCode {
             CheckCode::E999 => CheckKind::SyntaxError("`...`".to_string()),
             // pycodestyle warnings
             CheckCode::W292 => CheckKind::NoNewLineAtEndOfFile,
+            CheckCode::W605 => CheckKind::InvalidEscapeSequence('c'),
             // pyflakes
-            CheckCode::F401 => CheckKind::UnusedImport(vec!["...".to_string()]),
+            CheckCode::F401 => CheckKind::UnusedImport(vec!["...".to_string()], false),
             CheckCode::F402 => CheckKind::ImportShadowedByLoopVar("...".to_string(), 1),
             CheckCode::F403 => CheckKind::ImportStarUsed("...".to_string()),
             CheckCode::F404 => CheckKind::LateFutureImport,
@@ -469,6 +493,11 @@ impl CheckCode {
             // flake8-print
             CheckCode::T201 => CheckKind::PrintFound,
             CheckCode::T203 => CheckKind::PPrintFound,
+            // flake8-quotes
+            CheckCode::Q000 => CheckKind::BadQuotesInlineString(Quote::Double),
+            CheckCode::Q001 => CheckKind::BadQuotesMultilineString(Quote::Double),
+            CheckCode::Q002 => CheckKind::BadQuotesDocstring(Quote::Double),
+            CheckCode::Q003 => CheckKind::AvoidQuoteEscape,
             // pyupgrade
             CheckCode::U001 => CheckKind::UselessMetaclassType,
             CheckCode::U002 => CheckKind::UnnecessaryAbspath,
@@ -561,21 +590,22 @@ impl CheckCode {
 
     pub fn category(&self) -> CheckCategory {
         match self {
-            CheckCode::E402 => CheckCategory::Pycodestyle,
-            CheckCode::E501 => CheckCategory::Pycodestyle,
-            CheckCode::E711 => CheckCategory::Pycodestyle,
-            CheckCode::E712 => CheckCategory::Pycodestyle,
-            CheckCode::E713 => CheckCategory::Pycodestyle,
-            CheckCode::E714 => CheckCategory::Pycodestyle,
-            CheckCode::E721 => CheckCategory::Pycodestyle,
-            CheckCode::E722 => CheckCategory::Pycodestyle,
-            CheckCode::E731 => CheckCategory::Pycodestyle,
-            CheckCode::E741 => CheckCategory::Pycodestyle,
-            CheckCode::E742 => CheckCategory::Pycodestyle,
-            CheckCode::E743 => CheckCategory::Pycodestyle,
-            CheckCode::E902 => CheckCategory::Pycodestyle,
-            CheckCode::E999 => CheckCategory::Pycodestyle,
-            CheckCode::W292 => CheckCategory::Pycodestyle,
+            CheckCode::E402 => CheckCategory::PycodestyleError,
+            CheckCode::E501 => CheckCategory::PycodestyleError,
+            CheckCode::E711 => CheckCategory::PycodestyleError,
+            CheckCode::E712 => CheckCategory::PycodestyleError,
+            CheckCode::E713 => CheckCategory::PycodestyleError,
+            CheckCode::E714 => CheckCategory::PycodestyleError,
+            CheckCode::E721 => CheckCategory::PycodestyleError,
+            CheckCode::E722 => CheckCategory::PycodestyleError,
+            CheckCode::E731 => CheckCategory::PycodestyleError,
+            CheckCode::E741 => CheckCategory::PycodestyleError,
+            CheckCode::E742 => CheckCategory::PycodestyleError,
+            CheckCode::E743 => CheckCategory::PycodestyleError,
+            CheckCode::E902 => CheckCategory::PycodestyleError,
+            CheckCode::E999 => CheckCategory::PycodestyleError,
+            CheckCode::W292 => CheckCategory::PycodestyleWarning,
+            CheckCode::W605 => CheckCategory::PycodestyleWarning,
             CheckCode::F401 => CheckCategory::Pyflakes,
             CheckCode::F402 => CheckCategory::Pyflakes,
             CheckCode::F403 => CheckCategory::Pyflakes,
@@ -631,6 +661,10 @@ impl CheckCode {
             CheckCode::C417 => CheckCategory::Flake8Comprehensions,
             CheckCode::T201 => CheckCategory::Flake8Print,
             CheckCode::T203 => CheckCategory::Flake8Print,
+            CheckCode::Q000 => CheckCategory::Flake8Quotes,
+            CheckCode::Q001 => CheckCategory::Flake8Quotes,
+            CheckCode::Q002 => CheckCategory::Flake8Quotes,
+            CheckCode::Q003 => CheckCategory::Flake8Quotes,
             CheckCode::U001 => CheckCategory::Pyupgrade,
             CheckCode::U002 => CheckCategory::Pyupgrade,
             CheckCode::U003 => CheckCategory::Pyupgrade,
@@ -743,11 +777,12 @@ impl CheckKind {
             CheckKind::UndefinedExport(_) => &CheckCode::F822,
             CheckKind::UndefinedLocal(_) => &CheckCode::F823,
             CheckKind::UndefinedName(_) => &CheckCode::F821,
-            CheckKind::UnusedImport(_) => &CheckCode::F401,
+            CheckKind::UnusedImport(_, _) => &CheckCode::F401,
             CheckKind::UnusedVariable(_) => &CheckCode::F841,
             CheckKind::YieldOutsideFunction => &CheckCode::F704,
             // pycodestyle warnings
             CheckKind::NoNewLineAtEndOfFile => &CheckCode::W292,
+            CheckKind::InvalidEscapeSequence(_) => &CheckCode::W605,
             // flake8-builtins
             CheckKind::BuiltinVariableShadowing(_) => &CheckCode::A001,
             CheckKind::BuiltinArgumentShadowing(_) => &CheckCode::A002,
@@ -779,6 +814,11 @@ impl CheckKind {
             // flake8-print
             CheckKind::PrintFound => &CheckCode::T201,
             CheckKind::PPrintFound => &CheckCode::T203,
+            // flake8-quotes
+            CheckKind::BadQuotesInlineString(_) => &CheckCode::Q000,
+            CheckKind::BadQuotesMultilineString(_) => &CheckCode::Q001,
+            CheckKind::BadQuotesDocstring(_) => &CheckCode::Q002,
+            CheckKind::AvoidQuoteEscape => &CheckCode::Q003,
             // pyupgrade
             CheckKind::TypeOfPrimitive(_) => &CheckCode::U003,
             CheckKind::UnnecessaryAbspath => &CheckCode::U002,
@@ -971,9 +1011,13 @@ impl CheckKind {
             CheckKind::UndefinedName(name) => {
                 format!("Undefined name `{name}`")
             }
-            CheckKind::UnusedImport(names) => {
+            CheckKind::UnusedImport(names, in_init_py) => {
                 let names = names.iter().map(|name| format!("`{name}`")).join(", ");
-                format!("{names} imported but unused")
+                if *in_init_py {
+                    format!("{names} imported but unused and missing from `__all__`")
+                } else {
+                    format!("{names} imported but unused")
+                }
             }
             CheckKind::UnusedVariable(name) => {
                 format!("Local variable `{name}` is assigned to but never used")
@@ -983,6 +1027,7 @@ impl CheckKind {
             }
             // pycodestyle warnings
             CheckKind::NoNewLineAtEndOfFile => "No newline at end of file".to_string(),
+            CheckKind::InvalidEscapeSequence(char) => format!("Invalid escape sequence: '\\{char}'"),
             // flake8-builtins
             CheckKind::BuiltinVariableShadowing(name) => {
                 format!("Variable `{name}` is shadowing a python builtin")
@@ -1087,6 +1132,26 @@ impl CheckKind {
             // flake8-print
             CheckKind::PrintFound => "`print` found".to_string(),
             CheckKind::PPrintFound => "`pprint` found".to_string(),
+            // flake8-quotes
+            CheckKind::BadQuotesInlineString(quote) => {
+                match quote {
+                    Quote::Single => "Double quotes found but single quotes preferred".to_string(),
+                    Quote::Double => "Single quotes found but double quotes preferred".to_string(),
+                }
+            },
+            CheckKind::BadQuotesMultilineString(quote) => {
+                match quote {
+                    Quote::Single => "Double quote multiline found but single quotes preferred".to_string(),
+                    Quote::Double => "Single quote multiline found but double quotes preferred".to_string(),
+                }
+            },
+            CheckKind::BadQuotesDocstring(quote) => {
+                match quote {
+                    Quote::Single => "Double quote docstring found but single quotes preferred".to_string(),
+                    Quote::Double => "Single quote docstring found but double quotes preferred".to_string(),
+                }
+            },
+            CheckKind::AvoidQuoteEscape => "Change outer quotes to avoid escaping inner quotes".to_string(),
             // pyupgrade
             CheckKind::TypeOfPrimitive(primitive) => {
                 format!("Use `{}` instead of `type(...)`", primitive.builtin())
@@ -1328,7 +1393,7 @@ impl CheckKind {
                 | CheckKind::SuperCallWithParameters
                 | CheckKind::TypeOfPrimitive(_)
                 | CheckKind::UnnecessaryAbspath
-                | CheckKind::UnusedImport(_)
+                | CheckKind::UnusedImport(_, false)
                 | CheckKind::UnusedLoopControlVariable(_)
                 | CheckKind::UnusedNOQA(_)
                 | CheckKind::UsePEP585Annotation(_)

src/cli.rs

@@ -5,11 +5,11 @@ use clap::{command, Parser};
 use log::warn;
 use regex::Regex;
 
-use crate::checks::CheckCode;
+use crate::checks_gen::CheckCodePrefix;
 use crate::printer::SerializationFormat;
-use crate::pyproject::StrCheckCodePair;
-use crate::settings::PythonVersion;
-use crate::RawSettings;
+use crate::settings::configuration::Configuration;
+use crate::settings::types::PythonVersion;
+use crate::settings::types::StrCheckCodePair;
 
 #[derive(Debug, Parser)]
 #[command(author, about = "ruff: An extremely fast Python linter.")]
@@ -21,11 +21,14 @@ pub struct Cli {
     #[arg(long)]
     pub config: Option<PathBuf>,
     /// Enable verbose logging.
-    #[arg(short, long)]
+    #[arg(short, long, group = "verbosity")]
     pub verbose: bool,
-    /// Disable all logging (but still exit with status code "1" upon detecting errors).
-    #[arg(short, long)]
+    /// Only log errors.
+    #[arg(short, long, group = "verbosity")]
     pub quiet: bool,
+    /// Disable all logging (but still exit with status code "1" upon detecting errors).
+    #[arg(short, long, group = "verbosity")]
+    pub silent: bool,
     /// Exit with status code "0", even upon detecting errors.
     #[arg(short, long)]
     pub exit_zero: bool,
@@ -40,16 +43,16 @@ pub struct Cli {
     pub no_cache: bool,
     /// List of error codes to enable.
     #[arg(long, value_delimiter = ',')]
-    pub select: Vec<CheckCode>,
+    pub select: Vec<CheckCodePrefix>,
     /// Like --select, but adds additional error codes on top of the selected ones.
     #[arg(long, value_delimiter = ',')]
-    pub extend_select: Vec<CheckCode>,
+    pub extend_select: Vec<CheckCodePrefix>,
     /// List of error codes to ignore.
     #[arg(long, value_delimiter = ',')]
-    pub ignore: Vec<CheckCode>,
+    pub ignore: Vec<CheckCodePrefix>,
     /// Like --ignore, but adds additional error codes on top of the ignored ones.
     #[arg(long, value_delimiter = ',')]
-    pub extend_ignore: Vec<CheckCode>,
+    pub extend_ignore: Vec<CheckCodePrefix>,
     /// List of paths, used to exclude files and/or directories from checks.
     #[arg(long, value_delimiter = ',')]
     pub exclude: Vec<String>,
@@ -103,10 +106,10 @@ impl fmt::Display for Warnable {
 /// Warn the user if they attempt to enable a code that won't be respected.
 pub fn warn_on(
     flag: Warnable,
-    codes: &[CheckCode],
-    cli_ignore: &[CheckCode],
-    cli_extend_ignore: &[CheckCode],
-    pyproject_settings: &RawSettings,
+    codes: &[CheckCodePrefix],
+    cli_ignore: &[CheckCodePrefix],
+    cli_extend_ignore: &[CheckCodePrefix],
+    pyproject_configuration: &Configuration,
     pyproject_path: &Option<PathBuf>,
 ) {
     for code in codes {
@@ -114,7 +117,7 @@ pub fn warn_on(
             if cli_ignore.contains(code) {
                 warn!("{code:?} was passed to {flag}, but ignored via --ignore")
             }
-        } else if pyproject_settings.ignore.contains(code) {
+        } else if pyproject_configuration.ignore.contains(code) {
             if let Some(path) = pyproject_path {
                 warn!(
                     "{code:?} was passed to {flag}, but ignored by the `ignore` field in {}",
@@ -128,7 +131,7 @@ pub fn warn_on(
             if cli_extend_ignore.contains(code) {
                 warn!("{code:?} was passed to {flag}, but ignored via --extend-ignore")
             }
-        } else if pyproject_settings.extend_ignore.contains(code) {
+        } else if pyproject_configuration.extend_ignore.contains(code) {
             if let Some(path) = pyproject_path {
                 warn!(
                     "{code:?} was passed to {flag}, but ignored by the `extend_ignore` field in {}",

src/cst/helpers.rs

@@ -0,0 +1,42 @@
+use libcst_native::{Expression, NameOrAttribute};
+
+fn compose_call_path_inner<'a>(expr: &'a Expression, parts: &mut Vec<&'a str>) {
+    match &expr {
+        Expression::Call(expr) => {
+            compose_call_path_inner(&expr.func, parts);
+        }
+        Expression::Attribute(expr) => {
+            compose_call_path_inner(&expr.value, parts);
+            parts.push(expr.attr.value);
+        }
+        Expression::Name(expr) => {
+            parts.push(expr.value);
+        }
+        _ => {}
+    }
+}
+
+pub fn compose_call_path(expr: &Expression) -> Option<String> {
+    let mut segments = vec![];
+    compose_call_path_inner(expr, &mut segments);
+    if segments.is_empty() {
+        None
+    } else {
+        Some(segments.join("."))
+    }
+}
+
+pub fn compose_module_path(module: &NameOrAttribute) -> String {
+    match module {
+        NameOrAttribute::N(name) => name.value.to_string(),
+        NameOrAttribute::A(attr) => {
+            let name = attr.attr.value;
+            let prefix = compose_call_path(&attr.value);
+            if let Some(prefix) = prefix {
+                format!("{prefix}.{name}")
+            } else {
+                name.to_string()
+            }
+        }
+    }
+}

src/cst/mod.rs

@@ -0,0 +1 @@
+pub mod helpers;

src/flake8_comprehensions/checks.rs

@@ -37,7 +37,7 @@ fn first_argument_with_matching_function<'a>(
     Some(&args.first()?.node)
 }
 
-/// Check `list(generator)` compliance.
+/// C400 (`list(generator)`)
 pub fn unnecessary_generator_list(expr: &Expr, func: &Expr, args: &[Expr]) -> Option<Check> {
     let argument = exactly_one_argument_with_matching_function("list", func, args)?;
     if let ExprKind::GeneratorExp { .. } = argument {
@@ -49,7 +49,7 @@ pub fn unnecessary_generator_list(expr: &Expr, func: &Expr, args: &[Expr]) -> Op
     None
 }
 
-/// Check `set(generator)` compliance.
+/// C401 (`set(generator)`)
 pub fn unnecessary_generator_set(expr: &Expr, func: &Expr, args: &[Expr]) -> Option<Check> {
     let argument = exactly_one_argument_with_matching_function("set", func, args)?;
     if let ExprKind::GeneratorExp { .. } = argument {
@@ -61,7 +61,7 @@ pub fn unnecessary_generator_set(expr: &Expr, func: &Expr, args: &[Expr]) -> Opt
     None
 }
 
-/// Check `dict((x, y) for x, y in iterable)` compliance.
+/// C402 (`dict((x, y) for x, y in iterable)`)
 pub fn unnecessary_generator_dict(expr: &Expr, func: &Expr, args: &[Expr]) -> Option<Check> {
     let argument = exactly_one_argument_with_matching_function("dict", func, args)?;
     if let ExprKind::GeneratorExp { elt, .. } = argument {
@@ -78,7 +78,7 @@ pub fn unnecessary_generator_dict(expr: &Expr, func: &Expr, args: &[Expr]) -> Op
     None
 }
 
-/// Check `set([...])` compliance.
+/// C403 (`set([...])`)
 pub fn unnecessary_list_comprehension_set(
     expr: &Expr,
     func: &Expr,
@@ -94,7 +94,7 @@ pub fn unnecessary_list_comprehension_set(
     None
 }
 
-/// Check `dict([...])` compliance.
+/// C404 (`dict([...])`)
 pub fn unnecessary_list_comprehension_dict(
     expr: &Expr,
     func: &Expr,
@@ -115,7 +115,7 @@ pub fn unnecessary_list_comprehension_dict(
     None
 }
 
-/// Check `set([1, 2])` compliance.
+/// C405 (`set([1, 2])`)
 pub fn unnecessary_literal_set(expr: &Expr, func: &Expr, args: &[Expr]) -> Option<Check> {
     let argument = exactly_one_argument_with_matching_function("set", func, args)?;
     let kind = match argument {
@@ -129,7 +129,7 @@ pub fn unnecessary_literal_set(expr: &Expr, func: &Expr, args: &[Expr]) -> Optio
     ))
 }
 
-/// Check `dict([(1, 2)])` compliance.
+/// C406 (`dict([(1, 2)])`)
 pub fn unnecessary_literal_dict(expr: &Expr, func: &Expr, args: &[Expr]) -> Option<Check> {
     let argument = exactly_one_argument_with_matching_function("dict", func, args)?;
     let (kind, elts) = match argument {
@@ -151,6 +151,7 @@ pub fn unnecessary_literal_dict(expr: &Expr, func: &Expr, args: &[Expr]) -> Opti
     ))
 }
 
+/// C408
 pub fn unnecessary_collection_call(
     expr: &Expr,
     func: &Expr,
@@ -162,10 +163,10 @@ pub fn unnecessary_collection_call(
     }
     let id = function_name(func)?;
     match id {
+        "dict" if keywords.is_empty() || keywords.iter().all(|kw| kw.node.arg.is_some()) => (),
         "list" | "tuple" => {
             // list() or tuple()
         }
-        "dict" if keywords.is_empty() || keywords.iter().all(|kw| kw.node.arg.is_some()) => (),
         _ => return None,
     };
     Some(Check::new(
@@ -174,6 +175,7 @@ pub fn unnecessary_collection_call(
     ))
 }
 
+/// C409
 pub fn unnecessary_literal_within_tuple_call(
     expr: &Expr,
     func: &Expr,
@@ -191,6 +193,7 @@ pub fn unnecessary_literal_within_tuple_call(
     ))
 }
 
+/// C410
 pub fn unnecessary_literal_within_list_call(
     expr: &Expr,
     func: &Expr,
@@ -208,6 +211,7 @@ pub fn unnecessary_literal_within_list_call(
     ))
 }
 
+/// C411
 pub fn unnecessary_list_call(expr: &Expr, func: &Expr, args: &[Expr]) -> Option<Check> {
     let argument = first_argument_with_matching_function("list", func, args)?;
     if let ExprKind::ListComp { .. } = argument {
@@ -219,6 +223,7 @@ pub fn unnecessary_list_call(expr: &Expr, func: &Expr, args: &[Expr]) -> Option<
     None
 }
 
+/// C413
 pub fn unnecessary_call_around_sorted(expr: &Expr, func: &Expr, args: &[Expr]) -> Option<Check> {
     let outer = function_name(func)?;
     if !(outer == "list" || outer == "reversed") {
@@ -235,6 +240,7 @@ pub fn unnecessary_call_around_sorted(expr: &Expr, func: &Expr, args: &[Expr]) -
     None
 }
 
+/// C414
 pub fn unnecessary_double_cast_or_process(
     expr: &Expr,
     func: &Expr,
@@ -274,6 +280,7 @@ pub fn unnecessary_double_cast_or_process(
     None
 }
 
+/// C415
 pub fn unnecessary_subscript_reversal(expr: &Expr, func: &Expr, args: &[Expr]) -> Option<Check> {
     let first_arg = args.first()?;
     let id = function_name(func)?;
@@ -309,6 +316,7 @@ pub fn unnecessary_subscript_reversal(expr: &Expr, func: &Expr, args: &[Expr]) -
     None
 }
 
+/// C416
 pub fn unnecessary_comprehension(
     expr: &Expr,
     elt: &Expr,
@@ -337,6 +345,7 @@ pub fn unnecessary_comprehension(
     ))
 }
 
+/// C417
 pub fn unnecessary_map(expr: &Expr, func: &Expr, args: &[Expr]) -> Option<Check> {
     fn new_check(kind: &str, expr: &Expr) -> Check {
         Check::new(

src/flake8_quotes/checks.rs

@@ -0,0 +1,298 @@
+use rustpython_ast::Location;
+
+use crate::ast::operations::SourceCodeLocator;
+use crate::ast::types::Range;
+use crate::checks::{Check, CheckKind};
+use crate::flake8_quotes::settings::{Quote, Settings};
+
+fn good_single(quote: &Quote) -> char {
+    match quote {
+        Quote::Single => '\'',
+        Quote::Double => '"',
+    }
+}
+
+fn bad_single(quote: &Quote) -> char {
+    match quote {
+        Quote::Double => '\'',
+        Quote::Single => '"',
+    }
+}
+
+fn good_multiline(quote: &Quote) -> &str {
+    match quote {
+        Quote::Single => "'''",
+        Quote::Double => "\"\"\"",
+    }
+}
+
+fn good_multiline_ending(quote: &Quote) -> &str {
+    match quote {
+        Quote::Single => "'\"\"\"",
+        Quote::Double => "\"'''",
+    }
+}
+
+fn good_docstring(quote: &Quote) -> &str {
+    match quote {
+        Quote::Single => "'''",
+        Quote::Double => "\"\"\"",
+    }
+}
+
+pub fn quotes(
+    locator: &SourceCodeLocator,
+    start: &Location,
+    end: &Location,
+    is_docstring: bool,
+    settings: &Settings,
+) -> Option<Check> {
+    let text = locator.slice_source_code_range(&Range {
+        location: *start,
+        end_location: *end,
+    });
+
+    // Remove any prefixes (e.g., remove `u` from `u"foo"`).
+    let last_quote_char = text.chars().last().unwrap();
+    let first_quote_char = text.find(last_quote_char).unwrap();
+    let prefix = &text[..first_quote_char].to_lowercase();
+    let raw_text = &text[first_quote_char..];
+
+    // Determine if the string is multiline-based.
+    let is_multiline = if raw_text.len() >= 3 {
+        let mut chars = raw_text.chars();
+        let first = chars.next().unwrap();
+        let second = chars.next().unwrap();
+        let third = chars.next().unwrap();
+        first == second && second == third
+    } else {
+        false
+    };
+
+    if is_docstring {
+        if raw_text.contains(good_docstring(&settings.docstring_quotes)) {
+            return None;
+        }
+
+        return Some(Check::new(
+            CheckKind::BadQuotesDocstring(settings.docstring_quotes.clone()),
+            Range {
+                location: *start,
+                end_location: *end,
+            },
+        ));
+    } else if is_multiline {
+        // If our string is or contains a known good string, ignore it.
+        if raw_text.contains(good_multiline(&settings.multiline_quotes)) {
+            return None;
+        }
+
+        // If our string ends with a known good ending, then ignore it.
+        if raw_text.ends_with(good_multiline_ending(&settings.multiline_quotes)) {
+            return None;
+        }
+
+        return Some(Check::new(
+            CheckKind::BadQuotesMultilineString(settings.multiline_quotes.clone()),
+            Range {
+                location: *start,
+                end_location: *end,
+            },
+        ));
+    } else {
+        let string_contents = &raw_text[1..raw_text.len() - 1];
+
+        // If we're using the preferred quotation type, check for escapes.
+        if last_quote_char == good_single(&settings.inline_quotes) {
+            if !settings.avoid_escape || prefix.contains('r') {
+                return None;
+            }
+            if string_contents.contains(good_single(&settings.inline_quotes))
+                && !string_contents.contains(bad_single(&settings.inline_quotes))
+            {
+                return Some(Check::new(
+                    CheckKind::AvoidQuoteEscape,
+                    Range {
+                        location: *start,
+                        end_location: *end,
+                    },
+                ));
+            }
+            return None;
+        }
+
+        // If we're not using the preferred type, only allow use to avoid escapes.
+        if !string_contents.contains(good_single(&settings.inline_quotes)) {
+            return Some(Check::new(
+                CheckKind::BadQuotesInlineString(settings.inline_quotes.clone()),
+                Range {
+                    location: *start,
+                    end_location: *end,
+                },
+            ));
+        }
+    }
+
+    None
+}
+
+#[cfg(test)]
+mod tests {
+    use std::path::Path;
+
+    use anyhow::Result;
+    use rustpython_parser::lexer::LexResult;
+    use test_case::test_case;
+
+    use crate::autofix::fixer;
+    use crate::checks::{Check, CheckCode};
+    use crate::flake8_quotes::settings::Quote;
+    use crate::linter::tokenize;
+    use crate::{flake8_quotes, linter, Settings};
+    use crate::{fs, noqa};
+
+    fn check_path(path: &Path, settings: &Settings, autofix: &fixer::Mode) -> Result<Vec<Check>> {
+        let contents = fs::read_file(path)?;
+        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_case(Path::new("doubles.py"))]
+    #[test_case(Path::new("doubles_escaped.py"))]
+    #[test_case(Path::new("doubles_multiline_string.py"))]
+    #[test_case(Path::new("doubles_noqa.py"))]
+    #[test_case(Path::new("doubles_wrapped.py"))]
+    fn doubles(path: &Path) -> Result<()> {
+        let snapshot = format!("doubles_{}", path.to_string_lossy());
+        let mut checks = check_path(
+            Path::new("./resources/test/fixtures/flake8_quotes")
+                .join(path)
+                .as_path(),
+            &Settings {
+                flake8_quotes: flake8_quotes::settings::Settings {
+                    inline_quotes: Quote::Single,
+                    multiline_quotes: Quote::Single,
+                    docstring_quotes: Quote::Single,
+                    avoid_escape: true,
+                },
+                ..Settings::for_rules(vec![
+                    CheckCode::Q000,
+                    CheckCode::Q001,
+                    CheckCode::Q002,
+                    CheckCode::Q003,
+                ])
+            },
+            &fixer::Mode::Generate,
+        )?;
+        checks.sort_by_key(|check| check.location);
+        insta::assert_yaml_snapshot!(snapshot, checks);
+        Ok(())
+    }
+
+    #[test_case(Path::new("singles.py"))]
+    #[test_case(Path::new("singles_escaped.py"))]
+    #[test_case(Path::new("singles_multiline_string.py"))]
+    #[test_case(Path::new("singles_noqa.py"))]
+    #[test_case(Path::new("singles_wrapped.py"))]
+    fn singles(path: &Path) -> Result<()> {
+        let snapshot = format!("singles_{}", path.to_string_lossy());
+        let mut checks = check_path(
+            Path::new("./resources/test/fixtures/flake8_quotes")
+                .join(path)
+                .as_path(),
+            &Settings {
+                flake8_quotes: flake8_quotes::settings::Settings {
+                    inline_quotes: Quote::Double,
+                    multiline_quotes: Quote::Double,
+                    docstring_quotes: Quote::Double,
+                    avoid_escape: true,
+                },
+                ..Settings::for_rules(vec![
+                    CheckCode::Q000,
+                    CheckCode::Q001,
+                    CheckCode::Q002,
+                    CheckCode::Q003,
+                ])
+            },
+            &fixer::Mode::Generate,
+        )?;
+        checks.sort_by_key(|check| check.location);
+        insta::assert_yaml_snapshot!(snapshot, checks);
+        Ok(())
+    }
+
+    #[test_case(Path::new("docstring_doubles.py"))]
+    #[test_case(Path::new("docstring_doubles_module_multiline.py"))]
+    #[test_case(Path::new("docstring_doubles_module_singleline.py"))]
+    #[test_case(Path::new("docstring_doubles_class.py"))]
+    #[test_case(Path::new("docstring_doubles_function.py"))]
+    #[test_case(Path::new("docstring_singles.py"))]
+    #[test_case(Path::new("docstring_singles_module_multiline.py"))]
+    #[test_case(Path::new("docstring_singles_module_singleline.py"))]
+    #[test_case(Path::new("docstring_singles_class.py"))]
+    #[test_case(Path::new("docstring_singles_function.py"))]
+    fn double_docstring(path: &Path) -> Result<()> {
+        let snapshot = format!("double_docstring_{}", path.to_string_lossy());
+        let mut checks = check_path(
+            Path::new("./resources/test/fixtures/flake8_quotes")
+                .join(path)
+                .as_path(),
+            &Settings {
+                flake8_quotes: flake8_quotes::settings::Settings {
+                    inline_quotes: Quote::Single,
+                    multiline_quotes: Quote::Single,
+                    docstring_quotes: Quote::Double,
+                    avoid_escape: true,
+                },
+                ..Settings::for_rules(vec![
+                    CheckCode::Q000,
+                    CheckCode::Q001,
+                    CheckCode::Q002,
+                    CheckCode::Q003,
+                ])
+            },
+            &fixer::Mode::Generate,
+        )?;
+        checks.sort_by_key(|check| check.location);
+        insta::assert_yaml_snapshot!(snapshot, checks);
+        Ok(())
+    }
+
+    #[test_case(Path::new("docstring_doubles.py"))]
+    #[test_case(Path::new("docstring_doubles_module_multiline.py"))]
+    #[test_case(Path::new("docstring_doubles_module_singleline.py"))]
+    #[test_case(Path::new("docstring_doubles_class.py"))]
+    #[test_case(Path::new("docstring_doubles_function.py"))]
+    #[test_case(Path::new("docstring_singles.py"))]
+    #[test_case(Path::new("docstring_singles_module_multiline.py"))]
+    #[test_case(Path::new("docstring_singles_module_singleline.py"))]
+    #[test_case(Path::new("docstring_singles_class.py"))]
+    #[test_case(Path::new("docstring_singles_function.py"))]
+    fn single_docstring(path: &Path) -> Result<()> {
+        let snapshot = format!("single_docstring_{}", path.to_string_lossy());
+        let mut checks = check_path(
+            Path::new("./resources/test/fixtures/flake8_quotes")
+                .join(path)
+                .as_path(),
+            &Settings {
+                flake8_quotes: flake8_quotes::settings::Settings {
+                    inline_quotes: Quote::Single,
+                    multiline_quotes: Quote::Double,
+                    docstring_quotes: Quote::Single,
+                    avoid_escape: true,
+                },
+                ..Settings::for_rules(vec![
+                    CheckCode::Q000,
+                    CheckCode::Q001,
+                    CheckCode::Q002,
+                    CheckCode::Q003,
+                ])
+            },
+            &fixer::Mode::Generate,
+        )?;
+        checks.sort_by_key(|check| check.location);
+        insta::assert_yaml_snapshot!(snapshot, checks);
+        Ok(())
+    }
+}

src/flake8_quotes/docstring_detection.rs

@@ -0,0 +1,118 @@
+//! Extract docstrings via tokenization.
+//!
+//! See: https://github.com/zheller/flake8-quotes/blob/ef0d9a90249a080e460b70ab62bf4b65e5aa5816/flake8_quotes/docstring_detection.py#L29
+//!
+//! TODO(charlie): Consolidate with the existing AST-based docstring extraction.
+
+use rustpython_parser::lexer::Tok;
+
+#[derive(Debug)]
+enum State {
+    // Start of the module: first string gets marked as a docstring.
+    ExpectModuleDocstring,
+    // After seeing a class definition, we're waiting for the block colon (and do bracket counting).
+    ExpectClassColon,
+    // After seeing the block colon in a class definition, we expect a docstring.
+    ExpectClassDocstring,
+    // Same as ExpectClassColon, but for function definitions.
+    ExpectFunctionColon,
+    // Same as ExpectClassDocstring, but for function definitions.
+    ExpectFunctionDocstring,
+    // Skip tokens until we observe a `class` or `def`.
+    Other,
+}
+
+pub struct StateMachine {
+    state: State,
+    bracket_count: usize,
+}
+
+impl StateMachine {
+    pub fn new() -> Self {
+        Self {
+            state: State::ExpectModuleDocstring,
+            bracket_count: 0,
+        }
+    }
+
+    pub fn consume(&mut self, tok: &Tok) -> bool {
+        if matches!(tok, Tok::Newline | Tok::Indent | Tok::Dedent) {
+            return false;
+        }
+
+        if matches!(tok, Tok::String { .. }) {
+            return if matches!(
+                self.state,
+                State::ExpectModuleDocstring
+                    | State::ExpectClassDocstring
+                    | State::ExpectFunctionDocstring
+            ) {
+                self.state = State::Other;
+                true
+            } else {
+                false
+            };
+        }
+
+        if matches!(tok, Tok::Class) {
+            self.state = State::ExpectClassColon;
+            self.bracket_count = 0;
+            return false;
+        }
+
+        if matches!(tok, Tok::Def) {
+            self.state = State::ExpectFunctionColon;
+            self.bracket_count = 0;
+            return false;
+        }
+
+        if matches!(tok, Tok::Colon) {
+            if self.bracket_count == 0 {
+                if matches!(self.state, State::ExpectClassColon) {
+                    self.state = State::ExpectClassDocstring;
+                } else if matches!(self.state, State::ExpectFunctionColon) {
+                    self.state = State::ExpectFunctionDocstring;
+                }
+            }
+            return false;
+        }
+
+        if matches!(tok, Tok::Lpar | Tok::Lbrace | Tok::Lsqb) {
+            self.bracket_count += 1;
+            if matches!(
+                self.state,
+                State::ExpectModuleDocstring
+                    | State::ExpectClassDocstring
+                    | State::ExpectFunctionDocstring
+            ) {
+                self.state = State::Other;
+            }
+            return false;
+        }
+
+        if matches!(tok, Tok::Rpar | Tok::Rbrace | Tok::Rsqb) {
+            self.bracket_count -= 1;
+            if matches!(
+                self.state,
+                State::ExpectModuleDocstring
+                    | State::ExpectClassDocstring
+                    | State::ExpectFunctionDocstring
+            ) {
+                self.state = State::Other;
+            }
+            return false;
+        }
+
+        if matches!(
+            self.state,
+            State::ExpectModuleDocstring
+                | State::ExpectClassDocstring
+                | State::ExpectFunctionDocstring
+        ) {
+            self.state = State::Other;
+            return false;
+        }
+
+        false
+    }
+}

src/flake8_quotes/mod.rs

@@ -0,0 +1,3 @@
+pub mod checks;
+pub mod docstring_detection;
+pub mod settings;

src/flake8_quotes/settings.rs

@@ -0,0 +1,49 @@
+//! Settings for the `flake_quotes` plugin.
+
+use serde::{Deserialize, Serialize};
+
+#[derive(Debug, Clone, PartialEq, Eq, Deserialize, Serialize)]
+#[serde(deny_unknown_fields, rename_all = "kebab-case")]
+pub enum Quote {
+    Single,
+    Double,
+}
+
+#[derive(Debug, PartialEq, Eq, Deserialize)]
+#[serde(deny_unknown_fields, rename_all = "kebab-case")]
+pub struct Options {
+    pub inline_quotes: Option<Quote>,
+    pub multiline_quotes: Option<Quote>,
+    pub docstring_quotes: Option<Quote>,
+    pub avoid_escape: Option<bool>,
+}
+
+#[derive(Debug)]
+pub struct Settings {
+    pub inline_quotes: Quote,
+    pub multiline_quotes: Quote,
+    pub docstring_quotes: Quote,
+    pub avoid_escape: bool,
+}
+
+impl Settings {
+    pub fn from_config(config: Options) -> Self {
+        Self {
+            inline_quotes: config.inline_quotes.unwrap_or(Quote::Single),
+            multiline_quotes: config.multiline_quotes.unwrap_or(Quote::Double),
+            docstring_quotes: config.docstring_quotes.unwrap_or(Quote::Double),
+            avoid_escape: config.avoid_escape.unwrap_or(true),
+        }
+    }
+}
+
+impl Default for Settings {
+    fn default() -> Self {
+        Self {
+            inline_quotes: Quote::Single,
+            multiline_quotes: Quote::Double,
+            docstring_quotes: Quote::Double,
+            avoid_escape: true,
+        }
+    }
+}

src/flake8_quotes/snapshots/ruff__flake8_quotes__checks__tests__double_docstring_docstring_doubles.py.snap

@@ -0,0 +1,50 @@
+---
+source: src/flake8_quotes/checks.rs
+expression: checks
+---
+- kind:
+    BadQuotesMultilineString: single
+  location:
+    row: 5
+    column: 1
+  end_location:
+    row: 7
+    column: 4
+  fix: ~
+- kind:
+    BadQuotesMultilineString: single
+  location:
+    row: 16
+    column: 5
+  end_location:
+    row: 18
+    column: 8
+  fix: ~
+- kind:
+    BadQuotesMultilineString: single
+  location:
+    row: 21
+    column: 21
+  end_location:
+    row: 22
+    column: 38
+  fix: ~
+- kind:
+    BadQuotesMultilineString: single
+  location:
+    row: 30
+    column: 9
+  end_location:
+    row: 32
+    column: 12
+  fix: ~
+- kind:
+    BadQuotesMultilineString: single
+  location:
+    row: 35
+    column: 13
+  end_location:
+    row: 37
+    column: 16
+  fix: ~
+

src/flake8_quotes/snapshots/ruff__flake8_quotes__checks__tests__double_docstring_docstring_doubles_class.py.snap

@@ -0,0 +1,23 @@
+---
+source: src/flake8_quotes/checks.rs
+expression: checks
+---
+- kind:
+    BadQuotesMultilineString: single
+  location:
+    row: 3
+    column: 5
+  end_location:
+    row: 3
+    column: 28
+  fix: ~
+- kind:
+    BadQuotesMultilineString: single
+  location:
+    row: 5
+    column: 23
+  end_location:
+    row: 5
+    column: 44
+  fix: ~
+

src/flake8_quotes/snapshots/ruff__flake8_quotes__checks__tests__double_docstring_docstring_doubles_function.py.snap

@@ -0,0 +1,50 @@
+---
+source: src/flake8_quotes/checks.rs
+expression: checks
+---
+- kind:
+    BadQuotesMultilineString: single
+  location:
+    row: 3
+    column: 5
+  end_location:
+    row: 3
+    column: 27
+  fix: ~
+- kind:
+    BadQuotesMultilineString: single
+  location:
+    row: 11
+    column: 5
+  end_location:
+    row: 11
+    column: 27
+  fix: ~
+- kind:
+    BadQuotesMultilineString: single
+  location:
+    row: 15
+    column: 39
+  end_location:
+    row: 17
+    column: 4
+  fix: ~
+- kind:
+    BadQuotesMultilineString: single
+  location:
+    row: 17
+    column: 5
+  end_location:
+    row: 17
+    column: 20
+  fix: ~
+- kind:
+    BadQuotesMultilineString: single
+  location:
+    row: 21
+    column: 5
+  end_location:
+    row: 21
+    column: 28
+  fix: ~
+

src/flake8_quotes/snapshots/ruff__flake8_quotes__checks__tests__double_docstring_docstring_doubles_module_multiline.py.snap

@@ -0,0 +1,23 @@
+---
+source: src/flake8_quotes/checks.rs
+expression: checks
+---
+- kind:
+    BadQuotesMultilineString: single
+  location:
+    row: 4
+    column: 1
+  end_location:
+    row: 6
+    column: 4
+  fix: ~
+- kind:
+    BadQuotesMultilineString: single
+  location:
+    row: 9
+    column: 1
+  end_location:
+    row: 11
+    column: 4
+  fix: ~
+

src/flake8_quotes/snapshots/ruff__flake8_quotes__checks__tests__double_docstring_docstring_doubles_module_singleline.py.snap

@@ -0,0 +1,23 @@
+---
+source: src/flake8_quotes/checks.rs
+expression: checks
+---
+- kind:
+    BadQuotesMultilineString: single
+  location:
+    row: 2
+    column: 1
+  end_location:
+    row: 2
+    column: 32
+  fix: ~
+- kind:
+    BadQuotesMultilineString: single
+  location:
+    row: 6
+    column: 1
+  end_location:
+    row: 6
+    column: 32
+  fix: ~
+

src/flake8_quotes/snapshots/ruff__flake8_quotes__checks__tests__double_docstring_docstring_singles.py.snap

@@ -0,0 +1,32 @@
+---
+source: src/flake8_quotes/checks.rs
+expression: checks
+---
+- kind:
+    BadQuotesDocstring: double
+  location:
+    row: 1
+    column: 1
+  end_location:
+    row: 3
+    column: 4
+  fix: ~
+- kind:
+    BadQuotesDocstring: double
+  location:
+    row: 14
+    column: 5
+  end_location:
+    row: 16
+    column: 8
+  fix: ~
+- kind:
+    BadQuotesDocstring: double
+  location:
+    row: 26
+    column: 9
+  end_location:
+    row: 28
+    column: 12
+  fix: ~
+

src/flake8_quotes/snapshots/ruff__flake8_quotes__checks__tests__double_docstring_docstring_singles_class.py.snap

@@ -0,0 +1,32 @@
+---
+source: src/flake8_quotes/checks.rs
+expression: checks
+---
+- kind:
+    BadQuotesDocstring: double
+  location:
+    row: 2
+    column: 5
+  end_location:
+    row: 2
+    column: 54
+  fix: ~
+- kind:
+    BadQuotesDocstring: double
+  location:
+    row: 6
+    column: 9
+  end_location:
+    row: 6
+    column: 58
+  fix: ~
+- kind:
+    BadQuotesDocstring: double
+  location:
+    row: 9
+    column: 29
+  end_location:
+    row: 9
+    column: 53
+  fix: ~
+

src/flake8_quotes/snapshots/ruff__flake8_quotes__checks__tests__double_docstring_docstring_singles_function.py.snap

@@ -0,0 +1,23 @@
+---
+source: src/flake8_quotes/checks.rs
+expression: checks
+---
+- kind:
+    BadQuotesDocstring: double
+  location:
+    row: 2
+    column: 5
+  end_location:
+    row: 2
+    column: 57
+  fix: ~
+- kind:
+    BadQuotesDocstring: double
+  location:
+    row: 8
+    column: 5
+  end_location:
+    row: 10
+    column: 8
+  fix: ~
+

src/flake8_quotes/snapshots/ruff__flake8_quotes__checks__tests__double_docstring_docstring_singles_module_multiline.py.snap

@@ -0,0 +1,14 @@
+---
+source: src/flake8_quotes/checks.rs
+expression: checks
+---
+- kind:
+    BadQuotesDocstring: double
+  location:
+    row: 1
+    column: 1
+  end_location:
+    row: 3
+    column: 4
+  fix: ~
+

src/flake8_quotes/snapshots/ruff__flake8_quotes__checks__tests__double_docstring_docstring_singles_module_singleline.py.snap

@@ -0,0 +1,14 @@
+---
+source: src/flake8_quotes/checks.rs
+expression: checks
+---
+- kind:
+    BadQuotesDocstring: double
+  location:
+    row: 1
+    column: 1
+  end_location:
+    row: 1
+    column: 50
+  fix: ~
+

src/flake8_quotes/snapshots/ruff__flake8_quotes__checks__tests__doubles_doubles.py.snap

@@ -0,0 +1,23 @@
+---
+source: src/flake8_quotes/checks.rs
+expression: checks
+---
+- kind:
+    BadQuotesInlineString: single
+  location:
+    row: 1
+    column: 25
+  end_location:
+    row: 1
+    column: 46
+  fix: ~
+- kind:
+    BadQuotesInlineString: single
+  location:
+    row: 2
+    column: 25
+  end_location:
+    row: 2
+    column: 47
+  fix: ~
+

src/flake8_quotes/snapshots/ruff__flake8_quotes__checks__tests__doubles_doubles_escaped.py.snap

@@ -0,0 +1,13 @@
+---
+source: src/flake8_quotes/checks.rs
+expression: checks
+---
+- kind: AvoidQuoteEscape
+  location:
+    row: 1
+    column: 26
+  end_location:
+    row: 1
+    column: 48
+  fix: ~
+

src/flake8_quotes/snapshots/ruff__flake8_quotes__checks__tests__doubles_doubles_multiline_string.py.snap

@@ -0,0 +1,14 @@
+---
+source: src/flake8_quotes/checks.rs
+expression: checks
+---
+- kind:
+    BadQuotesMultilineString: single
+  location:
+    row: 1
+    column: 5
+  end_location:
+    row: 3
+    column: 13
+  fix: ~
+

src/flake8_quotes/snapshots/ruff__flake8_quotes__checks__tests__doubles_doubles_noqa.py.snap

@@ -0,0 +1,6 @@
+---
+source: src/flake8_quotes/checks.rs
+expression: checks
+---
+[]
+

src/flake8_quotes/snapshots/ruff__flake8_quotes__checks__tests__doubles_doubles_wrapped.py.snap

@@ -0,0 +1,6 @@
+---
+source: src/flake8_quotes/checks.rs
+expression: checks
+---
+[]
+

src/flake8_quotes/snapshots/ruff__flake8_quotes__checks__tests__single_docstring_docstring_doubles.py.snap

@@ -0,0 +1,32 @@
+---
+source: src/flake8_quotes/checks.rs
+expression: checks
+---
+- kind:
+    BadQuotesDocstring: single
+  location:
+    row: 1
+    column: 1
+  end_location:
+    row: 3
+    column: 4
+  fix: ~
+- kind:
+    BadQuotesDocstring: single
+  location:
+    row: 12
+    column: 5
+  end_location:
+    row: 14
+    column: 8
+  fix: ~
+- kind:
+    BadQuotesDocstring: single
+  location:
+    row: 24
+    column: 9
+  end_location:
+    row: 26
+    column: 12
+  fix: ~
+

src/flake8_quotes/snapshots/ruff__flake8_quotes__checks__tests__single_docstring_docstring_doubles_class.py.snap

@@ -0,0 +1,32 @@
+---
+source: src/flake8_quotes/checks.rs
+expression: checks
+---
+- kind:
+    BadQuotesDocstring: single
+  location:
+    row: 2
+    column: 5
+  end_location:
+    row: 2
+    column: 54
+  fix: ~
+- kind:
+    BadQuotesDocstring: single
+  location:
+    row: 6
+    column: 9
+  end_location:
+    row: 6
+    column: 58
+  fix: ~
+- kind:
+    BadQuotesDocstring: single
+  location:
+    row: 9
+    column: 29
+  end_location:
+    row: 9
+    column: 53
+  fix: ~
+

src/flake8_quotes/snapshots/ruff__flake8_quotes__checks__tests__single_docstring_docstring_doubles_function.py.snap

@@ -0,0 +1,23 @@
+---
+source: src/flake8_quotes/checks.rs
+expression: checks
+---
+- kind:
+    BadQuotesDocstring: single
+  location:
+    row: 2
+    column: 5
+  end_location:
+    row: 2
+    column: 57
+  fix: ~
+- kind:
+    BadQuotesDocstring: single
+  location:
+    row: 8
+    column: 5
+  end_location:
+    row: 10
+    column: 8
+  fix: ~
+

src/flake8_quotes/snapshots/ruff__flake8_quotes__checks__tests__single_docstring_docstring_doubles_module_multiline.py.snap

@@ -0,0 +1,14 @@
+---
+source: src/flake8_quotes/checks.rs
+expression: checks
+---
+- kind:
+    BadQuotesDocstring: single
+  location:
+    row: 1
+    column: 1
+  end_location:
+    row: 3
+    column: 4
+  fix: ~
+

src/flake8_quotes/snapshots/ruff__flake8_quotes__checks__tests__single_docstring_docstring_doubles_module_singleline.py.snap

@@ -0,0 +1,14 @@
+---
+source: src/flake8_quotes/checks.rs
+expression: checks
+---
+- kind:
+    BadQuotesDocstring: single
+  location:
+    row: 1
+    column: 1
+  end_location:
+    row: 1
+    column: 50
+  fix: ~
+

src/flake8_quotes/snapshots/ruff__flake8_quotes__checks__tests__single_docstring_docstring_singles.py.snap

@@ -0,0 +1,59 @@
+---
+source: src/flake8_quotes/checks.rs
+expression: checks
+---
+- kind:
+    BadQuotesMultilineString: double
+  location:
+    row: 5
+    column: 1
+  end_location:
+    row: 7
+    column: 4
+  fix: ~
+- kind:
+    BadQuotesMultilineString: double
+  location:
+    row: 11
+    column: 21
+  end_location:
+    row: 13
+    column: 4
+  fix: ~
+- kind:
+    BadQuotesMultilineString: double
+  location:
+    row: 18
+    column: 5
+  end_location:
+    row: 20
+    column: 8
+  fix: ~
+- kind:
+    BadQuotesMultilineString: double
+  location:
+    row: 23
+    column: 21
+  end_location:
+    row: 24
+    column: 38
+  fix: ~
+- kind:
+    BadQuotesMultilineString: double
+  location:
+    row: 32
+    column: 9
+  end_location:
+    row: 34
+    column: 12
+  fix: ~
+- kind:
+    BadQuotesMultilineString: double
+  location:
+    row: 37
+    column: 13
+  end_location:
+    row: 39
+    column: 16
+  fix: ~
+

src/flake8_quotes/snapshots/ruff__flake8_quotes__checks__tests__single_docstring_docstring_singles_class.py.snap

@@ -0,0 +1,23 @@
+---
+source: src/flake8_quotes/checks.rs
+expression: checks
+---
+- kind:
+    BadQuotesMultilineString: double
+  location:
+    row: 3
+    column: 5
+  end_location:
+    row: 3
+    column: 28
+  fix: ~
+- kind:
+    BadQuotesMultilineString: double
+  location:
+    row: 5
+    column: 23
+  end_location:
+    row: 5
+    column: 44
+  fix: ~
+

src/flake8_quotes/snapshots/ruff__flake8_quotes__checks__tests__single_docstring_docstring_singles_function.py.snap

@@ -0,0 +1,50 @@
+---
+source: src/flake8_quotes/checks.rs
+expression: checks
+---
+- kind:
+    BadQuotesMultilineString: double
+  location:
+    row: 3
+    column: 5
+  end_location:
+    row: 3
+    column: 27
+  fix: ~
+- kind:
+    BadQuotesMultilineString: double
+  location:
+    row: 11
+    column: 5
+  end_location:
+    row: 11
+    column: 27
+  fix: ~
+- kind:
+    BadQuotesMultilineString: double
+  location:
+    row: 15
+    column: 39
+  end_location:
+    row: 17
+    column: 4
+  fix: ~
+- kind:
+    BadQuotesMultilineString: double
+  location:
+    row: 17
+    column: 5
+  end_location:
+    row: 17
+    column: 20
+  fix: ~
+- kind:
+    BadQuotesMultilineString: double
+  location:
+    row: 21
+    column: 5
+  end_location:
+    row: 21
+    column: 28
+  fix: ~
+

src/flake8_quotes/snapshots/ruff__flake8_quotes__checks__tests__single_docstring_docstring_singles_module_multiline.py.snap

@@ -0,0 +1,23 @@
+---
+source: src/flake8_quotes/checks.rs
+expression: checks
+---
+- kind:
+    BadQuotesMultilineString: double
+  location:
+    row: 4
+    column: 1
+  end_location:
+    row: 6
+    column: 4
+  fix: ~
+- kind:
+    BadQuotesMultilineString: double
+  location:
+    row: 9
+    column: 1
+  end_location:
+    row: 11
+    column: 4
+  fix: ~
+

src/flake8_quotes/snapshots/ruff__flake8_quotes__checks__tests__single_docstring_docstring_singles_module_singleline.py.snap

@@ -0,0 +1,23 @@
+---
+source: src/flake8_quotes/checks.rs
+expression: checks
+---
+- kind:
+    BadQuotesMultilineString: double
+  location:
+    row: 2
+    column: 1
+  end_location:
+    row: 2
+    column: 32
+  fix: ~
+- kind:
+    BadQuotesMultilineString: double
+  location:
+    row: 6
+    column: 1
+  end_location:
+    row: 6
+    column: 32
+  fix: ~
+

src/flake8_quotes/snapshots/ruff__flake8_quotes__checks__tests__singles_singles.py.snap

@@ -0,0 +1,23 @@
+---
+source: src/flake8_quotes/checks.rs
+expression: checks
+---
+- kind:
+    BadQuotesInlineString: double
+  location:
+    row: 1
+    column: 25
+  end_location:
+    row: 1
+    column: 46
+  fix: ~
+- kind:
+    BadQuotesInlineString: double
+  location:
+    row: 2
+    column: 25
+  end_location:
+    row: 2
+    column: 47
+  fix: ~
+

src/flake8_quotes/snapshots/ruff__flake8_quotes__checks__tests__singles_singles_escaped.py.snap

@@ -0,0 +1,13 @@
+---
+source: src/flake8_quotes/checks.rs
+expression: checks
+---
+- kind: AvoidQuoteEscape
+  location:
+    row: 1
+    column: 26
+  end_location:
+    row: 1
+    column: 48
+  fix: ~
+

src/flake8_quotes/snapshots/ruff__flake8_quotes__checks__tests__singles_singles_multiline_string.py.snap

@@ -0,0 +1,14 @@
+---
+source: src/flake8_quotes/checks.rs
+expression: checks
+---
+- kind:
+    BadQuotesMultilineString: double
+  location:
+    row: 1
+    column: 5
+  end_location:
+    row: 3
+    column: 13
+  fix: ~
+

src/flake8_quotes/snapshots/ruff__flake8_quotes__checks__tests__singles_singles_noqa.py.snap

@@ -0,0 +1,6 @@
+---
+source: src/flake8_quotes/checks.rs
+expression: checks
+---
+[]
+

src/flake8_quotes/snapshots/ruff__flake8_quotes__checks__tests__singles_singles_wrapped.py.snap

@@ -0,0 +1,6 @@
+---
+source: src/flake8_quotes/checks.rs
+expression: checks
+---
+[]
+

src/fs.rs

@@ -12,7 +12,7 @@ use path_absolutize::Absolutize;
 use walkdir::{DirEntry, WalkDir};
 
 use crate::checks::CheckCode;
-use crate::settings::{FilePattern, PerFileIgnore};
+use crate::settings::types::{FilePattern, PerFileIgnore};
 
 /// Extract the absolute path and basename (as strings) from a Path.
 fn extract_path_names(path: &Path) -> Result<(&str, &str)> {
@@ -133,7 +133,7 @@ pub fn ignores_from_path<'a>(
                 [&pattern_code_pair.pattern].into_iter(),
             )
         })
-        .map(|pattern_code_pair| &pattern_code_pair.code)
+        .flat_map(|pattern_code_pair| &pattern_code_pair.codes)
         .collect())
 }
 
@@ -178,7 +178,7 @@ mod tests {
     use path_absolutize::Absolutize;
 
     use crate::fs::{extract_path_names, is_excluded, is_included};
-    use crate::settings::FilePattern;
+    use crate::settings::types::FilePattern;
 
     #[test]
     fn inclusions() {

src/lib.rs

@@ -6,24 +6,31 @@ use anyhow::Result;
 use log::debug;
 use rustpython_parser::lexer::LexResult;
 
+use settings::pyproject;
+use settings::Settings;
+
 use crate::autofix::fixer::Mode;
 use crate::linter::{check_path, tokenize};
 use crate::message::Message;
-use crate::settings::{RawSettings, Settings};
+use crate::settings::configuration::Configuration;
 
 mod ast;
 mod autofix;
 pub mod cache;
 pub mod check_ast;
 mod check_lines;
+mod check_tokens;
 pub mod checks;
+mod checks_gen;
 pub mod cli;
 pub mod code_gen;
+mod cst;
 mod docstrings;
 mod flake8_bugbear;
 mod flake8_builtins;
 mod flake8_comprehensions;
 mod flake8_print;
+mod flake8_quotes;
 pub mod fs;
 pub mod linter;
 pub mod logging;
@@ -34,14 +41,13 @@ pub mod printer;
 mod pycodestyle;
 mod pydocstyle;
 mod pyflakes;
-pub mod pyproject;
 mod python;
 mod pyupgrade;
 pub mod settings;
 pub mod visibility;
 
 /// Run ruff over Python source code directly.
-pub fn check(path: &Path, contents: &str) -> Result<Vec<Message>> {
+pub fn check(path: &Path, contents: &str, quiet: bool) -> Result<Vec<Message>> {
     // Find the project root and pyproject.toml.
     let project_root = pyproject::find_project_root(&[path.to_path_buf()]);
     match &project_root {
@@ -54,7 +60,11 @@ pub fn check(path: &Path, contents: &str) -> Result<Vec<Message>> {
         None => debug!("Unable to find pyproject.toml; using default settings..."),
     };
 
-    let settings = Settings::from_raw(RawSettings::from_pyproject(&pyproject, &project_root)?);
+    let settings = Settings::from_configuration(Configuration::from_pyproject(
+        &pyproject,
+        &project_root,
+        quiet,
+    )?);
 
     // Tokenize once.
     let tokens: Vec<LexResult> = tokenize(contents);

src/linter.rs

@@ -14,6 +14,7 @@ use crate::autofix::fixer;
 use crate::autofix::fixer::fix_file;
 use crate::check_ast::check_ast;
 use crate::check_lines::check_lines;
+use crate::check_tokens::check_tokens;
 use crate::checks::{Check, CheckCode, CheckKind, LintSource};
 use crate::code_gen::SourceGenerator;
 use crate::message::Message;
@@ -45,6 +46,15 @@ pub(crate) fn check_path(
     // Aggregate all checks.
     let mut checks: Vec<Check> = vec![];
 
+    // Run the token-based checks.
+    if settings
+        .enabled
+        .iter()
+        .any(|check_code| matches!(check_code.lint_source(), LintSource::Tokens))
+    {
+        check_tokens(&mut checks, contents, &tokens, settings);
+    }
+
     // Run the AST-based checks.
     if settings
         .enabled
@@ -226,16 +236,12 @@ mod tests {
 
     use crate::autofix::fixer;
     use crate::checks::{Check, CheckCode};
-    use crate::linter;
     use crate::linter::tokenize;
     use crate::settings;
     use crate::{fs, noqa};
+    use crate::{linter, Settings};
 
-    fn check_path(
-        path: &Path,
-        settings: &settings::Settings,
-        autofix: &fixer::Mode,
-    ) -> Result<Vec<Check>> {
+    fn check_path(path: &Path, settings: &Settings, autofix: &fixer::Mode) -> Result<Vec<Check>> {
         let contents = fs::read_file(path)?;
         let tokens: Vec<LexResult> = tokenize(&contents);
         let noqa_line_for = noqa::extract_noqa_line_for(&tokens);
@@ -330,6 +336,7 @@ mod tests {
     #[test_case(CheckCode::F401, Path::new("F401_2.py"); "F401_2")]
     #[test_case(CheckCode::F401, Path::new("F401_3.py"); "F401_3")]
     #[test_case(CheckCode::F401, Path::new("F401_4.py"); "F401_4")]
+    #[test_case(CheckCode::F401, Path::new("F401_5.py"); "F401_5")]
     #[test_case(CheckCode::F402, Path::new("F402.py"); "F402")]
     #[test_case(CheckCode::F403, Path::new("F403.py"); "F403")]
     #[test_case(CheckCode::F404, Path::new("F404.py"); "F404")]
@@ -380,6 +387,7 @@ mod tests {
     #[test_case(CheckCode::W292, Path::new("W292_0.py"); "W292_0")]
     #[test_case(CheckCode::W292, Path::new("W292_1.py"); "W292_1")]
     #[test_case(CheckCode::W292, Path::new("W292_2.py"); "W292_2")]
+    #[test_case(CheckCode::W605, Path::new("W605.py"); "W605")]
     fn checks(check_code: CheckCode, path: &Path) -> Result<()> {
         let snapshot = format!("{}_{}", check_code.as_ref(), path.to_string_lossy());
         let mut checks = check_path(

src/main.rs

@@ -25,10 +25,11 @@ use ruff::linter::{lint_path, lint_stdin};
 use ruff::logging::set_up_logging;
 use ruff::message::Message;
 use ruff::printer::{Printer, SerializationFormat};
-use ruff::pyproject::{self};
-use ruff::settings::CurrentSettings;
-use ruff::settings::RawSettings;
-use ruff::settings::{FilePattern, PerFileIgnore, Settings};
+use ruff::settings::configuration::Configuration;
+use ruff::settings::pyproject;
+use ruff::settings::types::{FilePattern, PerFileIgnore};
+use ruff::settings::user::UserConfiguration;
+use ruff::settings::Settings;
 use ruff::tell_user;
 
 #[cfg(feature = "update-informer")]
@@ -73,10 +74,14 @@ fn check_for_updates() {
     }
 }
 
-fn show_settings(settings: RawSettings, project_root: Option<PathBuf>, pyproject: Option<PathBuf>) {
+fn show_settings(
+    configuration: Configuration,
+    project_root: Option<PathBuf>,
+    pyproject: Option<PathBuf>,
+) {
     println!(
         "{:#?}",
-        CurrentSettings::from_settings(settings, project_root, pyproject)
+        UserConfiguration::from_configuration(configuration, project_root, pyproject)
     );
 }
 
@@ -220,7 +225,8 @@ fn autoformat(files: &[PathBuf], settings: &Settings) -> Result<usize> {
 }
 
 fn inner_main() -> Result<ExitCode> {
-    let cli = Cli::parse();
+    let mut cli = Cli::parse();
+    cli.quiet |= cli.silent;
 
     set_up_logging(cli.verbose)?;
 
@@ -255,15 +261,15 @@ fn inner_main() -> Result<ExitCode> {
         .map(|pair| PerFileIgnore::new(pair, &project_root))
         .collect();
 
-    let mut settings = RawSettings::from_pyproject(&pyproject, &project_root)?;
+    let mut configuration = Configuration::from_pyproject(&pyproject, &project_root, cli.quiet)?;
     if !exclude.is_empty() {
-        settings.exclude = exclude;
+        configuration.exclude = exclude;
     }
     if !extend_exclude.is_empty() {
-        settings.extend_exclude = extend_exclude;
+        configuration.extend_exclude = extend_exclude;
     }
     if !per_file_ignores.is_empty() {
-        settings.per_file_ignores = per_file_ignores;
+        configuration.per_file_ignores = per_file_ignores;
     }
     if !cli.select.is_empty() {
         warn_on(
@@ -271,10 +277,10 @@ fn inner_main() -> Result<ExitCode> {
             &cli.select,
             &cli.ignore,
             &cli.extend_ignore,
-            &settings,
+            &configuration,
             &pyproject,
         );
-        settings.select = cli.select;
+        configuration.select = cli.select;
     }
     if !cli.extend_select.is_empty() {
         warn_on(
@@ -282,22 +288,22 @@ fn inner_main() -> Result<ExitCode> {
             &cli.extend_select,
             &cli.ignore,
             &cli.extend_ignore,
-            &settings,
+            &configuration,
             &pyproject,
         );
-        settings.extend_select = cli.extend_select;
+        configuration.extend_select = cli.extend_select;
     }
     if !cli.ignore.is_empty() {
-        settings.ignore = cli.ignore;
+        configuration.ignore = cli.ignore;
     }
     if !cli.extend_ignore.is_empty() {
-        settings.extend_ignore = cli.extend_ignore;
+        configuration.extend_ignore = cli.extend_ignore;
     }
     if let Some(target_version) = cli.target_version {
-        settings.target_version = target_version;
+        configuration.target_version = target_version;
     }
     if let Some(dummy_variable_rgx) = cli.dummy_variable_rgx {
-        settings.dummy_variable_rgx = dummy_variable_rgx;
+        configuration.dummy_variable_rgx = dummy_variable_rgx;
     }
 
     if cli.show_settings && cli.show_files {
@@ -305,11 +311,11 @@ fn inner_main() -> Result<ExitCode> {
         return Ok(ExitCode::FAILURE);
     }
     if cli.show_settings {
-        show_settings(settings, project_root, pyproject);
+        show_settings(configuration, project_root, pyproject);
         return Ok(ExitCode::SUCCESS);
     }
 
-    let settings = Settings::from_raw(settings);
+    let settings = Settings::from_configuration(configuration);
 
     if cli.show_files {
         show_files(&cli.files, &settings);
@@ -342,7 +348,7 @@ fn inner_main() -> Result<ExitCode> {
         tell_user!("Starting linter in watch mode...\n");
 
         let messages = run_once(&cli.files, &settings, !cli.no_cache, false)?;
-        if !cli.quiet {
+        if !cli.silent {
             printer.write_continuously(&messages)?;
         }
 
@@ -362,7 +368,7 @@ fn inner_main() -> Result<ExitCode> {
                             tell_user!("File change detected...\n");
 
                             let messages = run_once(&cli.files, &settings, !cli.no_cache, false)?;
-                            if !cli.quiet {
+                            if !cli.silent {
                                 printer.write_continuously(&messages)?;
                             }
                         }
@@ -388,13 +394,13 @@ fn inner_main() -> Result<ExitCode> {
                 let path = Path::new(&filename);
                 (
                     run_once_stdin(&settings, path, cli.fix)?,
-                    !cli.quiet && !cli.fix,
+                    !cli.silent && !cli.fix,
                     false,
                 )
             } else {
                 (
                     run_once(&cli.files, &settings, !cli.no_cache, cli.fix)?,
-                    !cli.quiet,
+                    !cli.silent,
                     !cli.quiet,
                 )
             };

src/noqa.rs

@@ -169,7 +169,6 @@ y = 2
 z = x + 1",
         )
         .collect();
-        println!("{:?}", extract_noqa_line_for(&lxr));
         assert_eq!(extract_noqa_line_for(&lxr), empty);
 
         let lxr: Vec<LexResult> = lexer::make_tokenizer(
@@ -179,7 +178,6 @@ y = 2
 z = x + 1",
         )
         .collect();
-        println!("{:?}", extract_noqa_line_for(&lxr));
         assert_eq!(extract_noqa_line_for(&lxr), empty);
 
         let lxr: Vec<LexResult> = lexer::make_tokenizer(
@@ -189,7 +187,6 @@ z = x + 1
         ",
         )
         .collect();
-        println!("{:?}", extract_noqa_line_for(&lxr));
         assert_eq!(extract_noqa_line_for(&lxr), empty);
 
         let lxr: Vec<LexResult> = lexer::make_tokenizer(
@@ -200,7 +197,6 @@ z = x + 1
         ",
         )
         .collect();
-        println!("{:?}", extract_noqa_line_for(&lxr));
         assert_eq!(extract_noqa_line_for(&lxr), empty);
 
         let lxr: Vec<LexResult> = lexer::make_tokenizer(

src/pycodestyle/checks.rs

@@ -1,6 +1,8 @@
 use itertools::izip;
+use rustpython_ast::Location;
 use rustpython_parser::ast::{Cmpop, Constant, Expr, ExprKind, Unaryop};
 
+use crate::ast::operations::SourceCodeLocator;
 use crate::ast::types::{CheckLocator, Range};
 use crate::checks::{Check, CheckKind, RejectedCmpop};
 
@@ -8,7 +10,7 @@ fn is_ambiguous_name(name: &str) -> bool {
     name == "l" || name == "I" || name == "O"
 }
 
-/// Check AmbiguousVariableName compliance.
+/// E741
 pub fn ambiguous_variable_name(name: &str, location: Range) -> Option<Check> {
     if is_ambiguous_name(name) {
         Some(Check::new(
@@ -20,7 +22,7 @@ pub fn ambiguous_variable_name(name: &str, location: Range) -> Option<Check> {
     }
 }
 
-/// Check AmbiguousClassName compliance.
+/// E742
 pub fn ambiguous_class_name(name: &str, location: Range) -> Option<Check> {
     if is_ambiguous_name(name) {
         Some(Check::new(
@@ -32,7 +34,7 @@ pub fn ambiguous_class_name(name: &str, location: Range) -> Option<Check> {
     }
 }
 
-/// Check AmbiguousFunctionName compliance.
+/// E743
 pub fn ambiguous_function_name(name: &str, location: Range) -> Option<Check> {
     if is_ambiguous_name(name) {
         Some(Check::new(
@@ -44,7 +46,7 @@ pub fn ambiguous_function_name(name: &str, location: Range) -> Option<Check> {
     }
 }
 
-/// Check DoNotAssignLambda compliance.
+/// E731
 pub fn do_not_assign_lambda(value: &Expr, location: Range) -> Option<Check> {
     if let ExprKind::Lambda { .. } = &value.node {
         Some(Check::new(CheckKind::DoNotAssignLambda, location))
@@ -53,7 +55,7 @@ pub fn do_not_assign_lambda(value: &Expr, location: Range) -> Option<Check> {
     }
 }
 
-/// Check NotInTest and NotIsTest compliance.
+/// E713, E714
 pub fn not_tests(
     op: &Unaryop,
     operand: &Expr,
@@ -92,7 +94,7 @@ pub fn not_tests(
     checks
 }
 
-/// Check TrueFalseComparison and NoneComparison compliance.
+/// E711, E712
 pub fn literal_comparisons(
     left: &Expr,
     ops: &[Cmpop],
@@ -201,7 +203,7 @@ pub fn literal_comparisons(
     checks
 }
 
-/// Check TypeComparison compliance.
+/// E721
 pub fn type_comparison(ops: &[Cmpop], comparators: &[Expr], location: Range) -> Vec<Check> {
     let mut checks: Vec<Check> = vec![];
 
@@ -236,3 +238,92 @@ pub fn type_comparison(ops: &[Cmpop], comparators: &[Expr], location: Range) ->
 
     checks
 }
+
+// See: https://docs.python.org/3/reference/lexical_analysis.html#string-and-bytes-literals
+const VALID_ESCAPE_SEQUENCES: &[char; 23] = &[
+    '\n', '\\', '\'', '"', 'a', 'b', 'f', 'n', 'r', 't', 'v', '0', '1', '2', '3', '4', '5', '6',
+    '7', 'x', // Escape sequences only recognized in string literals
+    'N', 'u', 'U',
+];
+
+/// Return the quotation markers used for a String token.
+fn extract_quote(text: &str) -> &str {
+    for quote in ["'''", "\"\"\"", "'", "\""] {
+        if text.ends_with(quote) {
+            return quote;
+        }
+    }
+
+    panic!("Unable to find quotation mark for String token.")
+}
+
+/// W605
+pub fn invalid_escape_sequence(
+    locator: &SourceCodeLocator,
+    start: &Location,
+    end: &Location,
+) -> Vec<Check> {
+    let mut checks = vec![];
+
+    let text = locator.slice_source_code_range(&Range {
+        location: *start,
+        end_location: *end,
+    });
+
+    // Determine whether the string is single- or triple-quoted.
+    let quote = extract_quote(text);
+    let quote_pos = text.find(quote).unwrap();
+    let prefix = text[..quote_pos].to_lowercase();
+    let body = &text[(quote_pos + quote.len())..(text.len() - quote.len())];
+
+    if !prefix.contains('r') {
+        let mut col_offset = 0;
+        let mut row_offset = 0;
+        let mut in_escape = false;
+        let mut chars = body.chars();
+        let mut current = chars.next();
+        let mut next = chars.next();
+        while let (Some(current_char), Some(next_char)) = (current, next) {
+            // If we see an escaped backslash, avoid treating the character _after_ the
+            // escaped backslash as itself an escaped character.
+            if in_escape {
+                in_escape = false;
+            } else {
+                in_escape = current_char == '\\' && next_char == '\\';
+                if current_char == '\\' && !VALID_ESCAPE_SEQUENCES.contains(&next_char) {
+                    // Compute the location of the escape sequence by offsetting the location of the
+                    // string token by the characters we've seen thus far.
+                    let location = if row_offset == 0 {
+                        Location::new(
+                            start.row() + row_offset,
+                            start.column() + prefix.len() + quote.len() + col_offset,
+                        )
+                    } else {
+                        Location::new(start.row() + row_offset, col_offset + 1)
+                    };
+                    let end_location = Location::new(location.row(), location.column() + 1);
+                    checks.push(Check::new(
+                        CheckKind::InvalidEscapeSequence(next_char),
+                        Range {
+                            location,
+                            end_location,
+                        },
+                    ))
+                }
+            }
+
+            // Track the offset from the start position as we iterate over the body.
+            if current_char == '\n' {
+                col_offset = 0;
+                row_offset += 1;
+            } else {
+                col_offset += 1;
+            }
+
+            current = next;
+            next = chars.next();
+        }
+    }
+
+    checks
+}

src/pyflakes/checks.rs

@@ -10,7 +10,7 @@ use rustpython_parser::ast::{
 use crate::ast::types::{BindingKind, CheckLocator, FunctionScope, Range, Scope, ScopeKind};
 use crate::checks::{Check, CheckKind};
 
-/// Check IfTuple compliance.
+/// F634
 pub fn if_tuple(test: &Expr, location: Range) -> Option<Check> {
     if let ExprKind::Tuple { elts, .. } = &test.node {
         if !elts.is_empty() {
@@ -20,7 +20,7 @@ pub fn if_tuple(test: &Expr, location: Range) -> Option<Check> {
     None
 }
 
-/// Check AssertTuple compliance.
+/// F631
 pub fn assert_tuple(test: &Expr, location: Range) -> Option<Check> {
     if let ExprKind::Tuple { elts, .. } = &test.node {
         if !elts.is_empty() {
@@ -30,7 +30,7 @@ pub fn assert_tuple(test: &Expr, location: Range) -> Option<Check> {
     None
 }
 
-/// Check UnusedVariable compliance.
+/// F841
 pub fn unused_variables(
     scope: &Scope,
     locator: &dyn CheckLocator,
@@ -63,7 +63,7 @@ pub fn unused_variables(
     checks
 }
 
-/// Check DefaultExceptNotLast compliance.
+/// F707
 pub fn default_except_not_last(handlers: &[Excepthandler]) -> Option<Check> {
     for (idx, handler) in handlers.iter().enumerate() {
         let ExcepthandlerKind::ExceptHandler { type_, .. } = &handler.node;
@@ -78,7 +78,7 @@ pub fn default_except_not_last(handlers: &[Excepthandler]) -> Option<Check> {
     None
 }
 
-/// Check RaiseNotImplemented compliance.
+/// F901
 pub fn raise_not_implemented(expr: &Expr) -> Option<Check> {
     match &expr.node {
         ExprKind::Call { func, .. } => {
@@ -105,7 +105,7 @@ pub fn raise_not_implemented(expr: &Expr) -> Option<Check> {
     None
 }
 
-/// Check DuplicateArgumentName compliance.
+/// F831
 pub fn duplicate_arguments(arguments: &Arguments) -> Vec<Check> {
     let mut checks: Vec<Check> = vec![];
 
@@ -153,7 +153,7 @@ fn convert_to_value(expr: &Expr) -> Option<DictionaryKey> {
     }
 }
 
-/// Check MultiValueRepeatedKeyLiteral and MultiValueRepeatedKeyVariable compliance.
+/// F601, F602
 pub fn repeated_keys(
     keys: &[Expr],
     check_repeated_literals: bool,
@@ -215,7 +215,7 @@ fn is_constant_non_singleton(expr: &Expr) -> bool {
     is_constant(expr) && !is_singleton(expr)
 }
 
-/// Check IsLiteral compliance.
+/// F632
 pub fn is_literal(left: &Expr, ops: &[Cmpop], comparators: &[Expr], location: Range) -> Vec<Check> {
     let mut checks: Vec<Check> = vec![];
 
@@ -232,7 +232,7 @@ pub fn is_literal(left: &Expr, ops: &[Cmpop], comparators: &[Expr], location: Ra
     checks
 }
 
-/// Check TwoStarredExpressions and TooManyExpressionsInStarredAssignment compliance.
+/// F621, F622
 pub fn starred_expressions(
     elts: &[Expr],
     check_too_many_expressions: bool,
@@ -262,7 +262,7 @@ pub fn starred_expressions(
     None
 }
 
-/// Check BreakOutsideLoop compliance.
+/// F701
 pub fn break_outside_loop(
     stmt: &Stmt,
     parents: &[&Stmt],
@@ -303,7 +303,7 @@ pub fn break_outside_loop(
     }
 }
 
-/// Check ContinueOutsideLoop compliance.
+/// F702
 pub fn continue_outside_loop(
     stmt: &Stmt,
     parents: &[&Stmt],

src/pyflakes/fixes.rs

@@ -1,11 +1,11 @@
-use libcst_native::ImportNames::Aliases;
-use libcst_native::NameOrAttribute::N;
-use libcst_native::{Codegen, SmallStatement, Statement};
+use anyhow::Result;
+use libcst_native::{Codegen, ImportNames, NameOrAttribute, SmallStatement, Statement};
 use rustpython_ast::Stmt;
 
 use crate::ast::operations::SourceCodeLocator;
 use crate::ast::types::Range;
 use crate::autofix::{helpers, Fix};
+use crate::cst::helpers::compose_module_path;
 
 /// Generate a Fix to remove any unused imports from an `import` statement.
 pub fn remove_unused_imports(
@@ -14,7 +14,7 @@ pub fn remove_unused_imports(
     stmt: &Stmt,
     parent: Option<&Stmt>,
     deleted: &[&Stmt],
-) -> anyhow::Result<Fix> {
+) -> Result<Fix> {
     let mut tree = match libcst_native::parse_module(
         locator.slice_source_code_range(&Range::from_located(stmt)),
         None,
@@ -40,13 +40,11 @@ pub fn remove_unused_imports(
     // Preserve the trailing comma (or not) from the last entry.
     let trailing_comma = aliases.last().and_then(|alias| alias.comma.clone());
 
-    // Identify unused imports from within the `import from`.
+    // Identify unused imports from within the `import`.
     let mut removable = vec![];
     for (index, alias) in aliases.iter().enumerate() {
-        if let N(import_name) = &alias.name {
-            if full_names.contains(&import_name.value) {
-                removable.push(index);
-            }
+        if full_names.contains(&compose_module_path(&alias.name).as_str()) {
+            removable.push(index);
         }
     }
     // TODO(charlie): This is quadratic.
@@ -79,7 +77,7 @@ pub fn remove_unused_import_froms(
     stmt: &Stmt,
     parent: Option<&Stmt>,
     deleted: &[&Stmt],
-) -> anyhow::Result<Fix> {
+) -> Result<Fix> {
     let mut tree = match libcst_native::parse_module(
         locator.slice_source_code_range(&Range::from_located(stmt)),
         None,
@@ -100,7 +98,8 @@ pub fn remove_unused_import_froms(
             "Expected node to be: SmallStatement::ImportFrom."
         ));
     };
-    let aliases = if let Aliases(aliases) = &mut body.names {
+
+    let aliases = if let ImportNames::Aliases(aliases) = &mut body.names {
         aliases
     } else {
         return Err(anyhow::anyhow!("Expected node to be: Aliases."));
@@ -112,13 +111,16 @@ pub fn remove_unused_import_froms(
     // Identify unused imports from within the `import from`.
     let mut removable = vec![];
     for (index, alias) in aliases.iter().enumerate() {
-        if let N(name) = &alias.name {
-            let import_name = if let Some(N(module_name)) = &body.module {
-                format!("{}.{}", module_name.value, name.value)
-            } else {
-                name.value.to_string()
-            };
-            if full_names.contains(&import_name.as_str()) {
+        if let NameOrAttribute::N(name) = &alias.name {
+            let import_name = name.value.to_string();
+            let full_name = body
+                .module
+                .as_ref()
+                .map(compose_module_path)
+                .map(|module_name| format!("{module_name}.{import_name}"))
+                .unwrap_or(import_name);
+
+            if full_names.contains(&full_name.as_str()) {
                 removable.push(index);
             }
         }

src/pyupgrade/checks.rs

@@ -5,7 +5,7 @@ use crate::ast::types::{Binding, BindingKind, Range, Scope, ScopeKind};
 use crate::checks::{Check, CheckKind};
 use crate::pyupgrade::types::Primitive;
 
-/// Check that `super()` has no args
+/// U008
 pub fn super_args(
     scope: &Scope,
     parents: &[&Stmt],
@@ -70,7 +70,7 @@ pub fn super_args(
     None
 }
 
-/// Check UselessMetaclassType compliance.
+/// U001
 pub fn useless_metaclass_type(targets: &[Expr], value: &Expr, location: Range) -> Option<Check> {
     if targets.len() == 1 {
         if let ExprKind::Name { id, .. } = targets.first().map(|expr| &expr.node).unwrap() {
@@ -86,7 +86,7 @@ pub fn useless_metaclass_type(targets: &[Expr], value: &Expr, location: Range) -
     None
 }
 
-/// Check UnnecessaryAbspath compliance.
+/// U002
 pub fn unnecessary_abspath(func: &Expr, args: &[Expr], location: Range) -> Option<Check> {
     // Validate the arguments.
     if args.len() == 1 {
@@ -106,7 +106,7 @@ pub fn unnecessary_abspath(func: &Expr, args: &[Expr], location: Range) -> Optio
     None
 }
 
-/// Check UselessObjectInheritance compliance.
+/// U004
 pub fn useless_object_inheritance(name: &str, bases: &[Expr], scope: &Scope) -> Option<Check> {
     for expr in bases {
         if let ExprKind::Name { id, .. } = &expr.node {
@@ -131,7 +131,7 @@ pub fn useless_object_inheritance(name: &str, bases: &[Expr], scope: &Scope) ->
     None
 }
 
-/// Check TypeOfPrimitive compliance.
+/// U003
 pub fn type_of_primitive(func: &Expr, args: &[Expr], location: Range) -> Option<Check> {
     // Validate the arguments.
     if args.len() == 1 {

src/settings.rs

@@ -1,320 +0,0 @@
-use std::collections::BTreeSet;
-use std::hash::{Hash, Hasher};
-use std::path::{Path, PathBuf};
-use std::str::FromStr;
-
-use anyhow::{anyhow, Result};
-use glob::Pattern;
-use once_cell::sync::Lazy;
-use regex::Regex;
-use serde::{Deserialize, Serialize};
-use strum::IntoEnumIterator;
-
-use crate::checks::{CheckCategory, CheckCode};
-use crate::fs;
-use crate::pyproject::{load_config, StrCheckCodePair};
-
-#[derive(Clone, Debug, PartialOrd, PartialEq, Eq, Serialize, Deserialize)]
-pub enum PythonVersion {
-    Py33,
-    Py34,
-    Py35,
-    Py36,
-    Py37,
-    Py38,
-    Py39,
-    Py310,
-    Py311,
-}
-
-impl FromStr for PythonVersion {
-    type Err = anyhow::Error;
-
-    fn from_str(string: &str) -> Result<Self, Self::Err> {
-        match string {
-            "py33" => Ok(PythonVersion::Py33),
-            "py34" => Ok(PythonVersion::Py34),
-            "py35" => Ok(PythonVersion::Py35),
-            "py36" => Ok(PythonVersion::Py36),
-            "py37" => Ok(PythonVersion::Py37),
-            "py38" => Ok(PythonVersion::Py38),
-            "py39" => Ok(PythonVersion::Py39),
-            "py310" => Ok(PythonVersion::Py310),
-            "py311" => Ok(PythonVersion::Py311),
-            _ => Err(anyhow!("Unknown version: {}", string)),
-        }
-    }
-}
-
-#[derive(Debug, Clone, Hash)]
-pub enum FilePattern {
-    Simple(&'static str),
-    Complex(Pattern, Option<Pattern>),
-}
-
-impl FilePattern {
-    pub fn from_user(pattern: &str, project_root: &Option<PathBuf>) -> Self {
-        let path = Path::new(pattern);
-        let absolute_path = match project_root {
-            Some(project_root) => fs::normalize_path_to(path, project_root),
-            None => fs::normalize_path(path),
-        };
-
-        let absolute = Pattern::new(&absolute_path.to_string_lossy()).expect("Invalid pattern.");
-        let basename = if !pattern.contains(std::path::MAIN_SEPARATOR) {
-            Some(Pattern::new(pattern).expect("Invalid pattern."))
-        } else {
-            None
-        };
-
-        FilePattern::Complex(absolute, basename)
-    }
-}
-
-#[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 RawSettings {
-    pub dummy_variable_rgx: Regex,
-    pub exclude: Vec<FilePattern>,
-    pub extend_exclude: Vec<FilePattern>,
-    pub extend_ignore: Vec<CheckCode>,
-    pub extend_select: Vec<CheckCode>,
-    pub ignore: Vec<CheckCode>,
-    pub line_length: usize,
-    pub per_file_ignores: Vec<PerFileIgnore>,
-    pub select: Vec<CheckCode>,
-    pub target_version: PythonVersion,
-}
-
-static DEFAULT_EXCLUDE: Lazy<Vec<FilePattern>> = Lazy::new(|| {
-    vec![
-        FilePattern::Simple(".bzr"),
-        FilePattern::Simple(".direnv"),
-        FilePattern::Simple(".eggs"),
-        FilePattern::Simple(".git"),
-        FilePattern::Simple(".hg"),
-        FilePattern::Simple(".mypy_cache"),
-        FilePattern::Simple(".nox"),
-        FilePattern::Simple(".pants.d"),
-        FilePattern::Simple(".ruff_cache"),
-        FilePattern::Simple(".svn"),
-        FilePattern::Simple(".tox"),
-        FilePattern::Simple(".venv"),
-        FilePattern::Simple("__pypackages__"),
-        FilePattern::Simple("_build"),
-        FilePattern::Simple("buck-out"),
-        FilePattern::Simple("build"),
-        FilePattern::Simple("dist"),
-        FilePattern::Simple("node_modules"),
-        FilePattern::Simple("venv"),
-    ]
-});
-
-static DEFAULT_DUMMY_VARIABLE_RGX: Lazy<Regex> =
-    Lazy::new(|| Regex::new("^(_+|(_+[a-zA-Z0-9_]*[a-zA-Z0-9]+?))$").unwrap());
-
-impl RawSettings {
-    pub fn from_pyproject(
-        pyproject: &Option<PathBuf>,
-        project_root: &Option<PathBuf>,
-    ) -> Result<Self> {
-        let config = load_config(pyproject)?;
-        Ok(RawSettings {
-            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(),
-            },
-            target_version: config.target_version.unwrap_or(PythonVersion::Py310),
-            exclude: config
-                .exclude
-                .map(|paths| {
-                    paths
-                        .iter()
-                        .map(|path| FilePattern::from_user(path, project_root))
-                        .collect()
-                })
-                .unwrap_or_else(|| DEFAULT_EXCLUDE.clone()),
-            extend_exclude: config
-                .extend_exclude
-                .iter()
-                .map(|path| FilePattern::from_user(path, project_root))
-                .collect(),
-            extend_ignore: config.extend_ignore,
-            select: config.select.unwrap_or_else(|| {
-                CheckCode::iter()
-                    .filter(|code| {
-                        matches!(
-                            code.category(),
-                            CheckCategory::Pycodestyle | CheckCategory::Pyflakes
-                        )
-                    })
-                    .collect()
-            }),
-            extend_select: config.extend_select,
-            ignore: config.ignore,
-            line_length: config.line_length.unwrap_or(88),
-            per_file_ignores: config
-                .per_file_ignores
-                .into_iter()
-                .map(|pair| PerFileIgnore::new(pair, project_root))
-                .collect(),
-        })
-    }
-}
-
-#[derive(Debug)]
-pub struct Settings {
-    pub dummy_variable_rgx: Regex,
-    pub enabled: BTreeSet<CheckCode>,
-    pub exclude: Vec<FilePattern>,
-    pub extend_exclude: Vec<FilePattern>,
-    pub line_length: usize,
-    pub per_file_ignores: Vec<PerFileIgnore>,
-    pub target_version: PythonVersion,
-}
-
-impl Settings {
-    pub fn from_raw(settings: RawSettings) -> Self {
-        // Materialize the set of enabled CheckCodes.
-        let mut enabled: BTreeSet<CheckCode> = BTreeSet::new();
-        enabled.extend(settings.select);
-        enabled.extend(settings.extend_select);
-        for code in &settings.ignore {
-            enabled.remove(code);
-        }
-        for code in &settings.extend_ignore {
-            enabled.remove(code);
-        }
-        Self {
-            dummy_variable_rgx: settings.dummy_variable_rgx,
-            enabled,
-            exclude: settings.exclude,
-            extend_exclude: settings.extend_exclude,
-            line_length: settings.line_length,
-            per_file_ignores: settings.per_file_ignores,
-            target_version: PythonVersion::Py310,
-        }
-    }
-
-    pub fn for_rule(check_code: CheckCode) -> Self {
-        Self {
-            dummy_variable_rgx: DEFAULT_DUMMY_VARIABLE_RGX.clone(),
-            enabled: BTreeSet::from([check_code]),
-            exclude: vec![],
-            extend_exclude: vec![],
-            line_length: 88,
-            per_file_ignores: vec![],
-            target_version: PythonVersion::Py310,
-        }
-    }
-
-    pub fn for_rules(check_codes: Vec<CheckCode>) -> Self {
-        Self {
-            dummy_variable_rgx: DEFAULT_DUMMY_VARIABLE_RGX.clone(),
-            enabled: BTreeSet::from_iter(check_codes),
-            exclude: vec![],
-            extend_exclude: vec![],
-            line_length: 88,
-            per_file_ignores: vec![],
-            target_version: PythonVersion::Py310,
-        }
-    }
-}
-
-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.enabled.iter() {
-            value.hash(state);
-        }
-        for value in self.per_file_ignores.iter() {
-            value.hash(state);
-        }
-    }
-}
-
-/// 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 dummy_variable_rgx: Regex,
-    pub exclude: Vec<Exclusion>,
-    pub extend_exclude: Vec<Exclusion>,
-    pub extend_ignore: Vec<CheckCode>,
-    pub extend_select: Vec<CheckCode>,
-    pub ignore: Vec<CheckCode>,
-    pub line_length: usize,
-    pub per_file_ignores: Vec<PerFileIgnore>,
-    pub select: Vec<CheckCode>,
-    pub target_version: PythonVersion,
-    pub project_root: Option<PathBuf>,
-    pub pyproject: Option<PathBuf>,
-}
-
-impl CurrentSettings {
-    pub fn from_settings(
-        settings: RawSettings,
-        project_root: Option<PathBuf>,
-        pyproject: Option<PathBuf>,
-    ) -> Self {
-        Self {
-            dummy_variable_rgx: settings.dummy_variable_rgx,
-            exclude: settings
-                .exclude
-                .into_iter()
-                .map(Exclusion::from_file_pattern)
-                .collect(),
-            extend_exclude: settings
-                .extend_exclude
-                .into_iter()
-                .map(Exclusion::from_file_pattern)
-                .collect(),
-            extend_ignore: settings.extend_ignore,
-            extend_select: settings.extend_select,
-            ignore: settings.ignore,
-            line_length: settings.line_length,
-            per_file_ignores: settings.per_file_ignores,
-            select: settings.select,
-            target_version: settings.target_version,
-            project_root,
-            pyproject,
-        }
-    }
-}

src/settings/configuration.rs

@@ -0,0 +1,105 @@
+//! User-provided program settings, taking into account pyproject.toml and command-line options.
+//! Structure mirrors the user-facing representation of the various parameters.
+
+use std::path::PathBuf;
+
+use anyhow::{anyhow, Result};
+use once_cell::sync::Lazy;
+use regex::Regex;
+
+use crate::checks_gen::CheckCodePrefix;
+use crate::flake8_quotes;
+use crate::settings::pyproject::load_options;
+use crate::settings::types::{FilePattern, PerFileIgnore, PythonVersion};
+
+#[derive(Debug)]
+pub struct Configuration {
+    pub dummy_variable_rgx: Regex,
+    pub exclude: Vec<FilePattern>,
+    pub extend_exclude: Vec<FilePattern>,
+    pub extend_ignore: Vec<CheckCodePrefix>,
+    pub extend_select: Vec<CheckCodePrefix>,
+    pub ignore: Vec<CheckCodePrefix>,
+    pub line_length: usize,
+    pub per_file_ignores: Vec<PerFileIgnore>,
+    pub select: Vec<CheckCodePrefix>,
+    pub target_version: PythonVersion,
+    // Plugins
+    pub flake8_quotes: flake8_quotes::settings::Settings,
+}
+
+static DEFAULT_EXCLUDE: Lazy<Vec<FilePattern>> = Lazy::new(|| {
+    vec![
+        FilePattern::Simple(".bzr"),
+        FilePattern::Simple(".direnv"),
+        FilePattern::Simple(".eggs"),
+        FilePattern::Simple(".git"),
+        FilePattern::Simple(".hg"),
+        FilePattern::Simple(".mypy_cache"),
+        FilePattern::Simple(".nox"),
+        FilePattern::Simple(".pants.d"),
+        FilePattern::Simple(".ruff_cache"),
+        FilePattern::Simple(".svn"),
+        FilePattern::Simple(".tox"),
+        FilePattern::Simple(".venv"),
+        FilePattern::Simple("__pypackages__"),
+        FilePattern::Simple("_build"),
+        FilePattern::Simple("buck-out"),
+        FilePattern::Simple("build"),
+        FilePattern::Simple("dist"),
+        FilePattern::Simple("node_modules"),
+        FilePattern::Simple("venv"),
+    ]
+});
+
+static DEFAULT_DUMMY_VARIABLE_RGX: Lazy<Regex> =
+    Lazy::new(|| Regex::new("^(_+|(_+[a-zA-Z0-9_]*[a-zA-Z0-9]+?))$").unwrap());
+
+impl Configuration {
+    pub fn from_pyproject(
+        pyproject: &Option<PathBuf>,
+        project_root: &Option<PathBuf>,
+        quiet: bool,
+    ) -> Result<Self> {
+        let options = load_options(pyproject, quiet)?;
+        Ok(Configuration {
+            dummy_variable_rgx: match options.dummy_variable_rgx {
+                Some(pattern) => Regex::new(&pattern)
+                    .map_err(|e| anyhow!("Invalid dummy-variable-rgx value: {e}"))?,
+                None => DEFAULT_DUMMY_VARIABLE_RGX.clone(),
+            },
+            target_version: options.target_version.unwrap_or(PythonVersion::Py310),
+            exclude: options
+                .exclude
+                .map(|paths| {
+                    paths
+                        .iter()
+                        .map(|path| FilePattern::from_user(path, project_root))
+                        .collect()
+                })
+                .unwrap_or_else(|| DEFAULT_EXCLUDE.clone()),
+            extend_exclude: options
+                .extend_exclude
+                .iter()
+                .map(|path| FilePattern::from_user(path, project_root))
+                .collect(),
+            extend_ignore: options.extend_ignore,
+            select: options
+                .select
+                .unwrap_or_else(|| vec![CheckCodePrefix::E, CheckCodePrefix::F]),
+            extend_select: options.extend_select,
+            ignore: options.ignore,
+            line_length: options.line_length.unwrap_or(88),
+            per_file_ignores: options
+                .per_file_ignores
+                .into_iter()
+                .map(|pair| PerFileIgnore::new(pair, project_root))
+                .collect(),
+            // Plugins
+            flake8_quotes: options
+                .flake8_quotes
+                .map(flake8_quotes::settings::Settings::from_config)
+                .unwrap_or_default(),
+        })
+    }
+}

src/settings/mod.rs

@@ -0,0 +1,161 @@
+//! Effective program settings, taking into account pyproject.toml and command-line options.
+//! Structure is optimized for internal usage, as opposed to external visibility or parsing.
+
+use std::collections::BTreeSet;
+use std::hash::{Hash, Hasher};
+
+use regex::Regex;
+
+use crate::checks::CheckCode;
+use crate::checks_gen::{CheckCodePrefix, PrefixSpecificity};
+use crate::flake8_quotes;
+use crate::settings::configuration::Configuration;
+use crate::settings::types::{FilePattern, PerFileIgnore, PythonVersion};
+
+pub mod configuration;
+pub mod options;
+pub mod pyproject;
+pub mod types;
+pub mod user;
+
+#[derive(Debug)]
+pub struct Settings {
+    pub dummy_variable_rgx: Regex,
+    pub enabled: BTreeSet<CheckCode>,
+    pub exclude: Vec<FilePattern>,
+    pub extend_exclude: Vec<FilePattern>,
+    pub line_length: usize,
+    pub per_file_ignores: Vec<PerFileIgnore>,
+    pub target_version: PythonVersion,
+    // Plugins
+    pub flake8_quotes: flake8_quotes::settings::Settings,
+}
+
+impl Settings {
+    pub fn from_configuration(config: Configuration) -> Self {
+        Self {
+            dummy_variable_rgx: config.dummy_variable_rgx,
+            enabled: resolve_codes(
+                &config.select,
+                &config.extend_select,
+                &config.ignore,
+                &config.extend_ignore,
+            ),
+            exclude: config.exclude,
+            extend_exclude: config.extend_exclude,
+            flake8_quotes: config.flake8_quotes,
+            line_length: config.line_length,
+            per_file_ignores: config.per_file_ignores,
+            target_version: config.target_version,
+        }
+    }
+
+    pub fn for_rule(check_code: CheckCode) -> Self {
+        Self {
+            dummy_variable_rgx: Regex::new("^(_+|(_+[a-zA-Z0-9_]*[a-zA-Z0-9]+?))$").unwrap(),
+            enabled: BTreeSet::from([check_code]),
+            exclude: vec![],
+            extend_exclude: vec![],
+            line_length: 88,
+            per_file_ignores: vec![],
+            target_version: PythonVersion::Py310,
+            flake8_quotes: Default::default(),
+        }
+    }
+
+    pub fn for_rules(check_codes: Vec<CheckCode>) -> Self {
+        Self {
+            dummy_variable_rgx: Regex::new("^(_+|(_+[a-zA-Z0-9_]*[a-zA-Z0-9]+?))$").unwrap(),
+            enabled: BTreeSet::from_iter(check_codes),
+            exclude: vec![],
+            extend_exclude: vec![],
+            line_length: 88,
+            per_file_ignores: vec![],
+            target_version: PythonVersion::Py310,
+            flake8_quotes: Default::default(),
+        }
+    }
+}
+
+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.enabled.iter() {
+            value.hash(state);
+        }
+        for value in self.per_file_ignores.iter() {
+            value.hash(state);
+        }
+    }
+}
+
+/// Given a set of selected and ignored prefixes, resolve the set of enabled error codes.
+fn resolve_codes(
+    select: &[CheckCodePrefix],
+    extend_select: &[CheckCodePrefix],
+    ignore: &[CheckCodePrefix],
+    extend_ignore: &[CheckCodePrefix],
+) -> BTreeSet<CheckCode> {
+    let mut codes: BTreeSet<CheckCode> = BTreeSet::new();
+    for specificity in [
+        PrefixSpecificity::Category,
+        PrefixSpecificity::Hundreds,
+        PrefixSpecificity::Tens,
+        PrefixSpecificity::Explicit,
+    ] {
+        for prefix in select {
+            if prefix.specificity() == specificity {
+                codes.extend(prefix.codes());
+            }
+        }
+        for prefix in extend_select {
+            if prefix.specificity() == specificity {
+                codes.extend(prefix.codes());
+            }
+        }
+        for prefix in ignore {
+            if prefix.specificity() == specificity {
+                for code in prefix.codes() {
+                    codes.remove(&code);
+                }
+            }
+        }
+        for prefix in extend_ignore {
+            if prefix.specificity() == specificity {
+                for code in prefix.codes() {
+                    codes.remove(&code);
+                }
+            }
+        }
+    }
+    codes
+}
+
+#[cfg(test)]
+mod tests {
+    use std::collections::BTreeSet;
+
+    use crate::checks::CheckCode;
+    use crate::checks_gen::CheckCodePrefix;
+    use crate::settings::resolve_codes;
+
+    #[test]
+    fn resolver() {
+        let actual = resolve_codes(&[CheckCodePrefix::W], &[], &[], &[]);
+        let expected = BTreeSet::from_iter([CheckCode::W292, CheckCode::W605]);
+        assert_eq!(actual, expected);
+
+        let actual = resolve_codes(&[CheckCodePrefix::W6], &[], &[], &[]);
+        let expected = BTreeSet::from_iter([CheckCode::W605]);
+        assert_eq!(actual, expected);
+
+        let actual = resolve_codes(&[CheckCodePrefix::W], &[], &[CheckCodePrefix::W292], &[]);
+        let expected = BTreeSet::from_iter([CheckCode::W605]);
+        assert_eq!(actual, expected);
+
+        let actual = resolve_codes(&[CheckCodePrefix::W605], &[], &[CheckCodePrefix::W605], &[]);
+        let expected = BTreeSet::from_iter([]);
+        assert_eq!(actual, expected);
+    }
+}

src/settings/options.rs

@@ -0,0 +1,28 @@
+//! Options that the user can provide via pyproject.toml.
+
+use serde::Deserialize;
+
+use crate::checks_gen::CheckCodePrefix;
+use crate::flake8_quotes;
+use crate::settings::types::{PythonVersion, StrCheckCodePair};
+
+#[derive(Debug, PartialEq, Eq, Deserialize, Default)]
+#[serde(deny_unknown_fields, rename_all = "kebab-case")]
+pub struct Options {
+    pub line_length: Option<usize>,
+    pub exclude: Option<Vec<String>>,
+    #[serde(default)]
+    pub extend_exclude: Vec<String>,
+    pub select: Option<Vec<CheckCodePrefix>>,
+    #[serde(default)]
+    pub extend_select: Vec<CheckCodePrefix>,
+    #[serde(default)]
+    pub ignore: Vec<CheckCodePrefix>,
+    #[serde(default)]
+    pub extend_ignore: Vec<CheckCodePrefix>,
+    #[serde(default)]
+    pub per_file_ignores: Vec<StrCheckCodePair>,
+    pub dummy_variable_rgx: Option<String>,
+    pub target_version: Option<PythonVersion>,
+    pub flake8_quotes: Option<flake8_quotes::settings::Options>,
+}

src/settings/pyproject.rs

@@ -1,103 +1,26 @@
-use std::path::{Path, PathBuf};
-use std::str::FromStr;
+//! Utilities for locating (and extracting configuration from) a pyproject.toml.
 
-use anyhow::{anyhow, Result};
+use std::path::{Path, PathBuf};
+
+use anyhow::Result;
 use common_path::common_path_all;
 use path_absolutize::Absolutize;
-use serde::de;
-use serde::{Deserialize, Deserializer};
+use serde::Deserialize;
 
-use crate::checks::CheckCode;
 use crate::fs;
-use crate::settings::PythonVersion;
-
-pub fn load_config(pyproject: &Option<PathBuf>) -> Result<Config> {
-    match pyproject {
-        Some(pyproject) => Ok(parse_pyproject_toml(pyproject)?
-            .tool
-            .and_then(|tool| tool.ruff)
-            .unwrap_or_default()),
-        None => {
-            eprintln!("No pyproject.toml found.");
-            eprintln!("Falling back to default configuration...");
-            Ok(Default::default())
-        }
-    }
-}
-
-#[derive(Debug, PartialEq, Eq, Deserialize, Default)]
-#[serde(deny_unknown_fields, rename_all = "kebab-case")]
-pub struct Config {
-    pub line_length: Option<usize>,
-    pub exclude: Option<Vec<String>>,
-    #[serde(default)]
-    pub extend_exclude: Vec<String>,
-    pub select: Option<Vec<CheckCode>>,
-    #[serde(default)]
-    pub extend_select: Vec<CheckCode>,
-    #[serde(default)]
-    pub ignore: Vec<CheckCode>,
-    #[serde(default)]
-    pub extend_ignore: Vec<CheckCode>,
-    #[serde(default)]
-    pub per_file_ignores: Vec<StrCheckCodePair>,
-    pub dummy_variable_rgx: Option<String>,
-    pub target_version: Option<PythonVersion>,
-}
-
-#[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 })
-    }
-}
+use crate::settings::options::Options;
 
 #[derive(Debug, PartialEq, Eq, Deserialize)]
 struct Tools {
-    ruff: Option<Config>,
+    ruff: Option<Options>,
 }
 
 #[derive(Debug, PartialEq, Eq, Deserialize)]
-struct PyProject {
+struct Pyproject {
     tool: Option<Tools>,
 }
 
-fn parse_pyproject_toml(path: &Path) -> Result<PyProject> {
+fn parse_pyproject_toml(path: &Path) -> Result<Pyproject> {
     let contents = fs::read_file(path)?;
     toml::from_str(&contents).map_err(|e| e.into())
 }
@@ -146,6 +69,22 @@ pub fn find_project_root(sources: &[PathBuf]) -> Option<PathBuf> {
     None
 }
 
+pub fn load_options(pyproject: &Option<PathBuf>, quiet: bool) -> Result<Options> {
+    match pyproject {
+        Some(pyproject) => Ok(parse_pyproject_toml(pyproject)?
+            .tool
+            .and_then(|tool| tool.ruff)
+            .unwrap_or_default()),
+        None => {
+            if !quiet {
+                eprintln!("No pyproject.toml found.");
+                eprintln!("Falling back to default configuration...");
+            }
+            Ok(Default::default())
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use std::env::current_dir;
@@ -154,26 +93,27 @@ mod tests {
 
     use anyhow::Result;
 
-    use crate::checks::CheckCode;
-    use crate::pyproject::{
-        find_project_root, find_pyproject_toml, parse_pyproject_toml, Config, PyProject, Tools,
+    use crate::checks_gen::CheckCodePrefix;
+    use crate::flake8_quotes;
+    use crate::flake8_quotes::settings::Quote;
+    use crate::settings::pyproject::{
+        find_project_root, find_pyproject_toml, parse_pyproject_toml, Options, Pyproject, Tools,
     };
-
-    use super::StrCheckCodePair;
+    use crate::settings::types::StrCheckCodePair;
 
     #[test]
     fn deserialize() -> Result<()> {
-        let pyproject: PyProject = toml::from_str(r#""#)?;
+        let pyproject: Pyproject = toml::from_str(r#""#)?;
         assert_eq!(pyproject.tool, None);
 
-        let pyproject: PyProject = toml::from_str(
+        let pyproject: Pyproject = toml::from_str(
             r#"
 [tool.black]
 "#,
         )?;
         assert_eq!(pyproject.tool, Some(Tools { ruff: None }));
 
-        let pyproject: PyProject = toml::from_str(
+        let pyproject: Pyproject = toml::from_str(
             r#"
 [tool.black]
 [tool.ruff]
@@ -182,7 +122,7 @@ mod tests {
         assert_eq!(
             pyproject.tool,
             Some(Tools {
-                ruff: Some(Config {
+                ruff: Some(Options {
                     line_length: None,
                     exclude: None,
                     extend_exclude: vec![],
@@ -193,11 +133,12 @@ mod tests {
                     per_file_ignores: vec![],
                     dummy_variable_rgx: None,
                     target_version: None,
+                    flake8_quotes: None
                 })
             })
         );
 
-        let pyproject: PyProject = toml::from_str(
+        let pyproject: Pyproject = toml::from_str(
             r#"
 [tool.black]
 [tool.ruff]
@@ -207,7 +148,7 @@ line-length = 79
         assert_eq!(
             pyproject.tool,
             Some(Tools {
-                ruff: Some(Config {
+                ruff: Some(Options {
                     line_length: Some(79),
                     exclude: None,
                     extend_exclude: vec![],
@@ -218,11 +159,12 @@ line-length = 79
                     per_file_ignores: vec![],
                     dummy_variable_rgx: None,
                     target_version: None,
+                    flake8_quotes: None
                 })
             })
         );
 
-        let pyproject: PyProject = toml::from_str(
+        let pyproject: Pyproject = toml::from_str(
             r#"
 [tool.black]
 [tool.ruff]
@@ -232,7 +174,7 @@ exclude = ["foo.py"]
         assert_eq!(
             pyproject.tool,
             Some(Tools {
-                ruff: Some(Config {
+                ruff: Some(Options {
                     line_length: None,
                     exclude: Some(vec!["foo.py".to_string()]),
                     extend_exclude: vec![],
@@ -243,11 +185,12 @@ exclude = ["foo.py"]
                     per_file_ignores: vec![],
                     dummy_variable_rgx: None,
                     target_version: None,
+                    flake8_quotes: None
                 })
             })
         );
 
-        let pyproject: PyProject = toml::from_str(
+        let pyproject: Pyproject = toml::from_str(
             r#"
 [tool.black]
 [tool.ruff]
@@ -257,22 +200,23 @@ select = ["E501"]
         assert_eq!(
             pyproject.tool,
             Some(Tools {
-                ruff: Some(Config {
+                ruff: Some(Options {
                     line_length: None,
                     exclude: None,
                     extend_exclude: vec![],
-                    select: Some(vec![CheckCode::E501]),
+                    select: Some(vec![CheckCodePrefix::E501]),
                     extend_select: vec![],
                     ignore: vec![],
                     extend_ignore: vec![],
                     per_file_ignores: vec![],
                     dummy_variable_rgx: None,
                     target_version: None,
+                    flake8_quotes: None
                 })
             })
         );
 
-        let pyproject: PyProject = toml::from_str(
+        let pyproject: Pyproject = toml::from_str(
             r#"
 [tool.black]
 [tool.ruff]
@@ -283,22 +227,23 @@ ignore = ["E501"]
         assert_eq!(
             pyproject.tool,
             Some(Tools {
-                ruff: Some(Config {
+                ruff: Some(Options {
                     line_length: None,
                     exclude: None,
                     extend_exclude: vec![],
                     select: None,
-                    extend_select: vec![CheckCode::M001],
-                    ignore: vec![CheckCode::E501],
+                    extend_select: vec![CheckCodePrefix::M001],
+                    ignore: vec![CheckCodePrefix::E501],
                     extend_ignore: vec![],
                     per_file_ignores: vec![],
                     dummy_variable_rgx: None,
                     target_version: None,
+                    flake8_quotes: None
                 })
             })
         );
 
-        assert!(toml::from_str::<PyProject>(
+        assert!(toml::from_str::<Pyproject>(
             r#"
 [tool.black]
 [tool.ruff]
@@ -307,7 +252,7 @@ line_length = 79
         )
         .is_err());
 
-        assert!(toml::from_str::<PyProject>(
+        assert!(toml::from_str::<Pyproject>(
             r#"
 [tool.black]
 [tool.ruff]
@@ -316,7 +261,7 @@ select = ["E123"]
         )
         .is_err());
 
-        assert!(toml::from_str::<PyProject>(
+        assert!(toml::from_str::<Pyproject>(
             r#"
 [tool.black]
 [tool.ruff]
@@ -348,7 +293,7 @@ other-attribute = 1
             .expect("Unable to find tool.ruff.");
         assert_eq!(
             config,
-            Config {
+            Options {
                 line_length: Some(88),
                 exclude: None,
                 extend_exclude: vec![
@@ -360,9 +305,18 @@ other-attribute = 1
                 extend_select: vec![],
                 ignore: vec![],
                 extend_ignore: vec![],
-                per_file_ignores: vec![],
+                per_file_ignores: vec![StrCheckCodePair {
+                    pattern: "__init__.py".to_string(),
+                    code: CheckCodePrefix::F401
+                }],
                 dummy_variable_rgx: None,
                 target_version: None,
+                flake8_quotes: Some(flake8_quotes::settings::Options {
+                    inline_quotes: Some(Quote::Single),
+                    multiline_quotes: Some(Quote::Double),
+                    docstring_quotes: Some(Quote::Double),
+                    avoid_escape: Some(true),
+                })
             }
         );
 
@@ -373,6 +327,8 @@ other-attribute = 1
     fn str_check_code_pair_strings() {
         let result = StrCheckCodePair::from_str("foo:E501");
         assert!(result.is_ok());
+        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");

src/settings/types.rs

@@ -0,0 +1,125 @@
+use std::collections::BTreeSet;
+use std::hash::Hash;
+use std::path::{Path, PathBuf};
+use std::str::FromStr;
+
+use anyhow::{anyhow, Result};
+use glob::Pattern;
+use serde::{de, Deserialize, Deserializer, Serialize};
+
+use crate::checks::CheckCode;
+use crate::checks_gen::CheckCodePrefix;
+use crate::fs;
+
+#[derive(Clone, Debug, PartialOrd, PartialEq, Eq, Serialize, Deserialize)]
+pub enum PythonVersion {
+    Py33,
+    Py34,
+    Py35,
+    Py36,
+    Py37,
+    Py38,
+    Py39,
+    Py310,
+    Py311,
+}
+
+impl FromStr for PythonVersion {
+    type Err = anyhow::Error;
+
+    fn from_str(string: &str) -> Result<Self, Self::Err> {
+        match string {
+            "py33" => Ok(PythonVersion::Py33),
+            "py34" => Ok(PythonVersion::Py34),
+            "py35" => Ok(PythonVersion::Py35),
+            "py36" => Ok(PythonVersion::Py36),
+            "py37" => Ok(PythonVersion::Py37),
+            "py38" => Ok(PythonVersion::Py38),
+            "py39" => Ok(PythonVersion::Py39),
+            "py310" => Ok(PythonVersion::Py310),
+            "py311" => Ok(PythonVersion::Py311),
+            _ => Err(anyhow!("Unknown version: {}", string)),
+        }
+    }
+}
+
+#[derive(Debug, Clone, Hash)]
+pub enum FilePattern {
+    Simple(&'static str),
+    Complex(Pattern, Option<Pattern>),
+}
+
+impl FilePattern {
+    pub fn from_user(pattern: &str, project_root: &Option<PathBuf>) -> Self {
+        let path = Path::new(pattern);
+        let absolute_path = match project_root {
+            Some(project_root) => fs::normalize_path_to(path, project_root),
+            None => fs::normalize_path(path),
+        };
+
+        let absolute = Pattern::new(&absolute_path.to_string_lossy()).expect("Invalid pattern.");
+        let basename = if !pattern.contains(std::path::MAIN_SEPARATOR) {
+            Some(Pattern::new(pattern).expect("Invalid pattern."))
+        } else {
+            None
+        };
+
+        FilePattern::Complex(absolute, basename)
+    }
+}
+
+#[derive(Debug, Clone, Hash)]
+pub struct PerFileIgnore {
+    pub pattern: FilePattern,
+    pub codes: BTreeSet<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 codes = BTreeSet::from_iter(user_in.code.codes());
+        Self { pattern, codes }
+    }
+}
+
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct StrCheckCodePair {
+    pub pattern: String,
+    pub code: CheckCodePrefix,
+}
+
+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].trim(), tokens[1].trim())
+        };
+        let code = CheckCodePrefix::from_str(code_string)?;
+        let pattern = pattern_str.into();
+        Ok(Self { pattern, code })
+    }
+}

src/settings/user.rs

@@ -0,0 +1,84 @@
+//! Structs to render user-facing settings.
+
+use std::path::PathBuf;
+
+use regex::Regex;
+
+use crate::checks_gen::CheckCodePrefix;
+use crate::settings::types::{FilePattern, PerFileIgnore, PythonVersion};
+use crate::{flake8_quotes, Configuration};
+
+/// 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 configuration.
+#[derive(Debug)]
+pub struct UserConfiguration {
+    pub dummy_variable_rgx: Regex,
+    pub exclude: Vec<Exclusion>,
+    pub extend_exclude: Vec<Exclusion>,
+    pub extend_ignore: Vec<CheckCodePrefix>,
+    pub extend_select: Vec<CheckCodePrefix>,
+    pub ignore: Vec<CheckCodePrefix>,
+    pub line_length: usize,
+    pub per_file_ignores: Vec<PerFileIgnore>,
+    pub select: Vec<CheckCodePrefix>,
+    pub target_version: PythonVersion,
+    // Plugins
+    pub flake8_quotes: flake8_quotes::settings::Settings,
+    // Non-settings exposed to the user
+    pub project_root: Option<PathBuf>,
+    pub pyproject: Option<PathBuf>,
+}
+
+impl UserConfiguration {
+    pub fn from_configuration(
+        settings: Configuration,
+        project_root: Option<PathBuf>,
+        pyproject: Option<PathBuf>,
+    ) -> Self {
+        Self {
+            dummy_variable_rgx: settings.dummy_variable_rgx,
+            exclude: settings
+                .exclude
+                .into_iter()
+                .map(Exclusion::from_file_pattern)
+                .collect(),
+            extend_exclude: settings
+                .extend_exclude
+                .into_iter()
+                .map(Exclusion::from_file_pattern)
+                .collect(),
+            extend_ignore: settings.extend_ignore,
+            extend_select: settings.extend_select,
+            ignore: settings.ignore,
+            line_length: settings.line_length,
+            per_file_ignores: settings.per_file_ignores,
+            select: settings.select,
+            target_version: settings.target_version,
+            flake8_quotes: settings.flake8_quotes,
+            project_root,
+            pyproject,
+        }
+    }
+}

src/snapshots/ruff__linter__tests__F401_F401_0.py.snap

@@ -4,7 +4,8 @@ expression: checks
 ---
 - kind:
     UnusedImport:
-      - functools
+      - - functools
+      - false
   location:
     row: 2
     column: 1
@@ -23,7 +24,8 @@ expression: checks
     applied: false
 - kind:
     UnusedImport:
-      - collections.OrderedDict
+      - - collections.OrderedDict
+      - false
   location:
     row: 4
     column: 1
@@ -42,7 +44,8 @@ expression: checks
     applied: false
 - kind:
     UnusedImport:
-      - logging.handlers
+      - - logging.handlers
+      - false
   location:
     row: 12
     column: 1
@@ -51,17 +54,18 @@ expression: checks
     column: 24
   fix:
     patch:
-      content: import logging.handlers
+      content: ""
       location:
         row: 12
         column: 1
       end_location:
-        row: 12
-        column: 24
+        row: 13
+        column: 1
     applied: false
 - kind:
     UnusedImport:
-      - shelve
+      - - shelve
+      - false
   location:
     row: 33
     column: 5
@@ -80,7 +84,8 @@ expression: checks
     applied: false
 - kind:
     UnusedImport:
-      - importlib
+      - - importlib
+      - false
   location:
     row: 34
     column: 5
@@ -99,7 +104,8 @@ expression: checks
     applied: false
 - kind:
     UnusedImport:
-      - pathlib
+      - - pathlib
+      - false
   location:
     row: 38
     column: 5
@@ -118,7 +124,8 @@ expression: checks
     applied: false
 - kind:
     UnusedImport:
-      - pickle
+      - - pickle
+      - false
   location:
     row: 53
     column: 9

src/snapshots/ruff__linter__tests__F401_F401_5.py.snap

@@ -0,0 +1,85 @@
+---
+source: src/linter.rs
+expression: checks
+---
+- kind:
+    UnusedImport:
+      - - a.b.c
+      - false
+  location:
+    row: 2
+    column: 1
+  end_location:
+    row: 2
+    column: 18
+  fix:
+    patch:
+      content: ""
+      location:
+        row: 2
+        column: 1
+      end_location:
+        row: 3
+        column: 1
+    applied: false
+- kind:
+    UnusedImport:
+      - - d.e.f
+      - false
+  location:
+    row: 3
+    column: 1
+  end_location:
+    row: 3
+    column: 23
+  fix:
+    patch:
+      content: ""
+      location:
+        row: 3
+        column: 1
+      end_location:
+        row: 4
+        column: 1
+    applied: false
+- kind:
+    UnusedImport:
+      - - h.i
+      - false
+  location:
+    row: 4
+    column: 1
+  end_location:
+    row: 4
+    column: 11
+  fix:
+    patch:
+      content: ""
+      location:
+        row: 4
+        column: 1
+      end_location:
+        row: 5
+        column: 1
+    applied: false
+- kind:
+    UnusedImport:
+      - - j.k
+      - false
+  location:
+    row: 5
+    column: 1
+  end_location:
+    row: 5
+    column: 16
+  fix:
+    patch:
+      content: ""
+      location:
+        row: 5
+        column: 1
+      end_location:
+        row: 6
+        column: 1
+    applied: false
+

src/snapshots/ruff__linter__tests__W605_W605.py.snap

@@ -0,0 +1,41 @@
+---
+source: src/linter.rs
+expression: checks
+---
+- kind:
+    InvalidEscapeSequence: "."
+  location:
+    row: 2
+    column: 10
+  end_location:
+    row: 2
+    column: 11
+  fix: ~
+- kind:
+    InvalidEscapeSequence: "."
+  location:
+    row: 6
+    column: 1
+  end_location:
+    row: 6
+    column: 2
+  fix: ~
+- kind:
+    InvalidEscapeSequence: _
+  location:
+    row: 11
+    column: 6
+  end_location:
+    row: 11
+    column: 7
+  fix: ~
+- kind:
+    InvalidEscapeSequence: _
+  location:
+    row: 18
+    column: 6
+  end_location:
+    row: 18
+    column: 7
+  fix: ~
+

src/snapshots/ruff__linter__tests__future_annotations.snap

@@ -4,7 +4,8 @@ expression: checks
 ---
 - kind:
     UnusedImport:
-      - models.Nut
+      - - models.Nut
+      - false
   location:
     row: 5
     column: 1