Bump version to 0.0.90

Use a single SourceCodeLocator everywhere (#510 )
Simplify SourceCodeLocator offset computation (#509 )
2022-10-29 18:34:38 -04:00 · 2022-10-29 18:23:24 -04:00 · 2022-10-29 18:13:42 -04:00 · 2022-10-29 17:40:50 -04:00 · 2022-10-29 17:07:46 -04:00 · 2022-10-29 17:00:30 -04:00
108 changed files with 4286 additions and 895 deletions
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -1,8 +1,8 @@
 repos:
  - repo: https://github.com/charliermarsh/ruff-pre-commit
-    rev: v0.0.40
+    rev: v0.0.90
    hooks:
-      - id: lint
+      - id: ruff

  - repo: https://github.com/abravalheri/validate-pyproject
    rev: v0.10.1
--- a/Cargo.lock
+++ b/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 = "0.0.85"
+version = "0.0.90"
 dependencies = [
 "anyhow",
 "assert_cmd",
@@ -2054,6 +2063,7 @@ dependencies = [
 "chrono",
 "clap",
 "clearscreen",
+ "codegen",
 "colored",
 "common-path",
 "dirs 4.0.0",
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "ruff"
-version = "0.0.85"
+version = "0.0.90"
 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" }

--- a/README.md
+++ b/README.md
@@ -38,13 +38,25 @@ Read the [launch blog post](https://notes.crmarsh.com/python-tooling-could-be-mu
 1. [Installation and Usage](#installation-and-usage)
 2. [Configuration](#configuration)
 3. [Supported Rules](#supported-rules)
-4. [Editor Integrations](#editor-integrations)
-5. [FAQ](#faq)
-6. [Development](#development)
-7. [Releases](#releases)
-8. [Benchmarks](#benchmarks)
-9. [License](#license)
-10. [Contributing](#contributing)
+   1. [Pyflakes](#pyflakes)
+   2. [pycodestyle (error)](#pycodestyle-error)
+   3. [pycodestyle (warning)](#pycodestyle-warning)
+   4. [pydocstyle](#pydocstyle)
+   5. [pyupgrade](#pyupgrade)
+   6. [pep8-naming](#pep8-naming)
+   7. [flake8-comprehensions](#flake8-comprehensions)
+   8. [flake8-bugbear](#flake8-bugbear)
+   9. [flake8-builtins](#flake8-builtins)
+   10. [flake8-print](#flake8-print)
+   11. [flake8-quotes](#flake8-quotes)
+   12. [Meta rules](#meta-rules)
+5. [Editor Integrations](#editor-integrations)
+6. [FAQ](#faq)
+7. [Development](#development)
+8. [Releases](#releases)
+9. [Benchmarks](#benchmarks)
+10. [License](#license)
+11. [Contributing](#contributing)

 ## Installation and Usage

@@ -77,11 +89,14 @@ Ruff also works with [pre-commit](https://pre-commit.com):
 ```yaml
 repos:
  - repo: https://github.com/charliermarsh/ruff-pre-commit
-    rev: v0.0.85
+    rev: v0.0.90
    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.
@@ -91,13 +106,25 @@ For example, you could configure Ruff to only enforce a subset of rules with:
 ```toml
 [tool.ruff]
 line-length = 88
-select = [
-    "F401",
-    "F403",
+select = ["E", "F"]
+ignore = ["E501"]
+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
@@ -219,8 +246,7 @@ add `noqa` directives to all failing lines, with the appropriate error codes.**

 ## Supported Rules

-By default, Ruff enables all `E`, `W`, and `F` error codes, which correspond to those built-in to
-Flake8.
+By default, Ruff enables all `E` and `F` error codes, which correspond to those built-in to Flake8.

 The 🛠 emoji indicates that a rule is automatically fixable by the `--fix` command-line option.

@@ -354,12 +380,16 @@ The 🛠 emoji indicates that a rule is automatically fixable by the `--fix` com
 | N803 | InvalidArgumentName | Argument name `...` should be lowercase |  |
 | N804 | InvalidFirstArgumentNameForClassMethod | First argument of a class method should be named `cls` |  |
 | N805 | InvalidFirstArgumentNameForMethod | First argument of a method should be named `self` |  |
+| N806 | NonLowercaseVariableInFunction | Variable `...` in function should be lowercase |  |
 | N807 | DunderFunctionName | Function name should not start and end with `__` |  |
 | N811 | ConstantImportedAsNonConstant | Constant `...` imported as non-constant `...` |  |
 | N812 | LowercaseImportedAsNonLowercase | Lowercase `...` imported as non-lowercase `...` |  |
 | N813 | CamelcaseImportedAsLowercase | Camelcase `...` imported as lowercase `...` |  |
 | N814 | CamelcaseImportedAsConstant | Camelcase `...` imported as constant `...` |  |
+| N815 | MixedCaseVariableInClassScope | Variable `mixedCase` in class scope should not be mixedCase |  |
+| N816 | MixedCaseVariableInGlobalScope | Variable `mixedCase` in global scope should not be mixedCase |  |
 | N817 | CamelcaseImportedAsAcronym | Camelcase `...` imported as acronym `...` |  |
+| N818 | ErrorSuffixOnExceptionName | Exception name `...` should be named with an Error suffix |  |

 ### flake8-comprehensions

@@ -379,7 +409,7 @@ The 🛠 emoji indicates that a rule is automatically fixable by the `--fix` com
 | C413 | UnnecessaryCallAroundSorted | Unnecessary `(list\|reversed)` call around `sorted()` |  |
 | C414 | UnnecessaryDoubleCastOrProcess | Unnecessary `(list\|reversed\|set\|sorted\|tuple)` call within `(list\|set\|sorted\|tuple)()` |  |
 | C415 | UnnecessarySubscriptReversal | Unnecessary subscript reversal of iterable within `(reversed\|set\|sorted)()` |  |
-| C416 | UnnecessaryComprehension |  Unnecessary `(list\|set)` comprehension (rewrite using `(list\|set)()`) |  |
+| C416 | UnnecessaryComprehension | Unnecessary `(list\|set)` comprehension (rewrite using `(list\|set)()`) |  |
 | C417 | UnnecessaryMap | Unnecessary `map` usage (rewrite using a `(list\|set\|dict)` comprehension) |  |

 ### flake8-bugbear
@@ -389,6 +419,7 @@ The 🛠 emoji indicates that a rule is automatically fixable by the `--fix` com
 | B002 | UnaryPrefixIncrement | Python does not support the unary prefix increment. |  |
 | B007 | UnusedLoopControlVariable | Loop control variable `i` not used within the loop body. | 🛠 |
 | B011 | DoNotAssertFalse | Do not `assert False` (`python -O` removes these calls), raise `AssertionError()` | 🛠 |
+| B013 | RedundantTupleInExceptionHandler | A length-one tuple literal is redundant. Write `except ValueError:` instead of `except (ValueError,):`. |  |
 | B014 | DuplicateHandlerException | Exception handler with duplicate exception: `ValueError` | 🛠 |
 | B017 | NoAssertRaisesException | `assertRaises(Exception):` should be considered evil. |  |
 | B025 | DuplicateTryBlockException | try-except block with duplicate exception `Exception` |  |
@@ -408,6 +439,15 @@ 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 |
@@ -474,13 +514,15 @@ Ruff re-implements some of the most popular Flake8 plugins and related code qual
 including:

 - [`pydocstyle`](https://pypi.org/project/pydocstyle/)
+- [`pep8-naming`](https://pypi.org/project/pep8-naming/)
 - [`yesqa`](https://github.com/asottile/yesqa)
 - [`flake8-docstrings`](https://pypi.org/project/flake8-docstrings/)
 - [`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)
+- [`flake8-bugbear`](https://pypi.org/project/flake8-bugbear/) (10/32)
 - [`pyupgrade`](https://pypi.org/project/pyupgrade/) (8/34)
 - [`autoflake`](https://pypi.org/project/autoflake/) (1/7)

@@ -495,10 +537,12 @@ Beyond rule-set parity, Ruff suffers from the following limitations vis-à-vis F

 Today, Ruff can be used to replace Flake8 when used with any of the following plugins:

+- [`pep8-naming`](https://pypi.org/project/pep8-naming/)
 - [`flake8-docstrings`](https://pypi.org/project/flake8-docstrings/)
 - [`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)

@@ -529,35 +573,55 @@ Yes! To enable a specific docstring convention, start by enabling all `pydocstyl
 then selectively disabling based on your [preferred convention](https://www.pydocstyle.org/en/latest/error_codes.html#default-conventions).

 For example, if you're coming from `flake8-docstrings`, the following configuration is equivalent to
-`--docstring-convention numpy`:
+`--docstring-convention=numpy`:

 ```toml
 [tool.ruff]
-extend-select = [
-    "D100",
-    "D101",
-    "D102",
-    "D103",
-    "D104",
-    "D105",
-    "D106",
-    "D200",
-    "D201",
-    "D202",
+extend-select = ["D"]
+extend-ignore = [
+    "D107",
+    "D203",
+    "D212",
+    "D213",
+    "D402",
+    "D413",
+    "D415",
+    "D416",
+    "D417",
+]
+```
+
+Similarly, the following is equivalent to `--docstring-convention=google`:
+
+```toml
+[tool.ruff]
+extend-select = ["D"]
+extend-ignore = [
+    "D203",
    "D204",
-    "D205",
-    "D206",
-    "D207",
-    "D208",
-    "D209",
-    "D210",
-    "D211",
+    "D213",
+    "D215",
+    "D400",
+    "D404",
+    "D406",
+    "D407",
+    "D408",
+    "D409",
+    "D413",
+]
+```
+
+Similarly, the following is equivalent to `--docstring-convention=pep8`:
+
+```toml
+[tool.ruff]
+extend-select = ["D"]
+extend-ignore = [
+    "D203",
+    "D212",
+    "D213",
    "D214",
    "D215",
-    "D300",
-    "D400",
-    "D402",
-    "D403",
    "D404",
    "D405",
    "D406",
@@ -566,51 +630,10 @@ extend-select = [
    "D409",
    "D410",
    "D411",
-    "D412",
    "D413",
-    "D418",
-    "D419",
-]
-```
-
-Similarly, the following is equivalent to `--docstring-convention google`:
-
-```toml
-[tool.ruff]
-extend-select = [
-    "D100",
-    "D101",
-    "D102",
-    "D103",
-    "D104",
-    "D105",
-    "D106",
-    "D107",
-    "D200",
-    "D201",
-    "D202",
-    "D205",
-    "D206",
-    "D207",
-    "D208",
-    "D209",
-    "D210",
-    "D211",
-    "D212",
-    "D214",
-    "D300",
-    "D402",
-    "D403",
-    "D405",
-    "D410",
-    "D411",
-    "D412",
-    "D414",
    "D415",
    "D416",
    "D417",
-    "D418",
-    "D419",
 ]
 ```

--- a/examples/generate_check_code_prefix.rs
+++ b/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());
+}
--- a/resources/test/fixtures/B013.py
+++ b/resources/test/fixtures/B013.py
@@ -0,0 +1,8 @@
+try:
+    pass
+except (ValueError,):
+    pass
+except AttributeError:
+    pass
+except (ImportError, TypeError):
+    pass
--- a/resources/test/fixtures/N802.py
+++ b/resources/test/fixtures/N802.py
@@ -1,3 +1,6 @@
+import unittest
+
+
 def Bad():
    pass

@@ -24,3 +27,15 @@ def _good():

 def good_func():
    pass
+
+
+def tearDownModule():
+    pass
+
+
+class Test(unittest.TestCase):
+    def tearDown(self):
+        return super().tearDown()
+
+    def testTest(self):
+        assert True
--- a/resources/test/fixtures/N806.py
+++ b/resources/test/fixtures/N806.py
@@ -0,0 +1,4 @@
+def f():
+    lower = 0
+    Camel = 0
+    CONSTANT = 0
--- a/resources/test/fixtures/N815.py
+++ b/resources/test/fixtures/N815.py
@@ -0,0 +1,6 @@
+class C:
+    lower = 0
+    CONSTANT = 0
+    mixedCase = 0
+    _mixedCase = 0
+    mixed_Case = 0
--- a/resources/test/fixtures/N816.py
+++ b/resources/test/fixtures/N816.py
@@ -0,0 +1,5 @@
+lower = 0
+CONSTANT = 0
+mixedCase = 0
+_mixedCase = 0
+mixed_Case = 0
--- a/resources/test/fixtures/N818.py
+++ b/resources/test/fixtures/N818.py
@@ -0,0 +1,10 @@
+class Error(Exception):
+    pass
+
+
+class AnotherError(Exception):
+    pass
+
+
+class C(Exception):
+    pass
--- a/resources/test/fixtures/init.py
+++ b/resources/test/fixtures/init.py
@@ -1,3 +1,5 @@
+import os
+
 print(__path__)

 __all__ = ["a", "b", "c"]
--- a/resources/test/fixtures/flake8_quotes/docstring_doubles.py
+++ b/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
--- a/resources/test/fixtures/flake8_quotes/docstring_doubles_class.py
+++ b/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
--- a/resources/test/fixtures/flake8_quotes/docstring_doubles_function.py
+++ b/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
--- a/resources/test/fixtures/flake8_quotes/docstring_doubles_module_multiline.py
+++ b/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
+"""
--- a/resources/test/fixtures/flake8_quotes/docstring_doubles_module_singleline.py
+++ b/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 """
--- a/resources/test/fixtures/flake8_quotes/docstring_singles.py
+++ b/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
--- a/resources/test/fixtures/flake8_quotes/docstring_singles_class.py
+++ b/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
--- a/resources/test/fixtures/flake8_quotes/docstring_singles_function.py
+++ b/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
+
--- a/resources/test/fixtures/flake8_quotes/docstring_singles_module_multiline.py
+++ b/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
+'''
--- a/resources/test/fixtures/flake8_quotes/docstring_singles_module_singleline.py
+++ b/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 '''
--- a/resources/test/fixtures/flake8_quotes/doubles.py
+++ b/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"
--- a/resources/test/fixtures/flake8_quotes/doubles_escaped.py
+++ b/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\''
--- a/resources/test/fixtures/flake8_quotes/doubles_multiline_string.py
+++ b/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'"""
--- a/resources/test/fixtures/flake8_quotes/doubles_noqa.py
+++ b/resources/test/fixtures/flake8_quotes/doubles_noqa.py
@@ -0,0 +1 @@
+this_should_not_be_linted = "double quote string"  # noqa
--- a/resources/test/fixtures/flake8_quotes/doubles_wrapped.py
+++ b/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"
--- a/resources/test/fixtures/flake8_quotes/singles.py
+++ b/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'
--- a/resources/test/fixtures/flake8_quotes/singles_escaped.py
+++ b/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\""
--- a/resources/test/fixtures/flake8_quotes/singles_multiline_string.py
+++ b/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"'''
--- a/resources/test/fixtures/flake8_quotes/singles_noqa.py
+++ b/resources/test/fixtures/flake8_quotes/singles_noqa.py
@@ -0,0 +1 @@
+this_should_not_be_linted = 'single quote string'  # noqa
--- a/resources/test/fixtures/flake8_quotes/singles_wrapped.py
+++ b/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'
--- a/resources/test/fixtures/pyproject.toml
+++ b/resources/test/fixtures/pyproject.toml
@@ -5,3 +5,34 @@ 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
+
+[tool.ruff.pep8-naming]
+ignore-names = [
+    "setUp",
+    "tearDown",
+    "setUpClass",
+    "tearDownClass",
+    "setUpModule",
+    "tearDownModule",
+    "asyncSetUp",
+    "asyncTearDown",
+    "setUpTestData",
+    "failureException",
+    "longMessage",
+    "maxDiff",
+]
+classmethod-decorators = [
+    "classmethod",
+]
+staticmethod-decorators = [
+    "staticmethod",
+]
--- a/src/ast/operations.rs
+++ b/src/ast/operations.rs
@@ -1,3 +1,4 @@
+use once_cell::unsync::OnceCell;
 use rustpython_parser::ast::{Constant, Expr, ExprKind, Location, Stmt, StmtKind};

 use crate::ast::types::{BindingKind, Range, Scope};
@@ -120,45 +121,47 @@ pub fn is_unpacking_assignment(stmt: &Stmt) -> bool {

 /// Struct used to efficiently slice source code at (row, column) Locations.
 pub struct SourceCodeLocator<'a> {
-    content: &'a str,
-    offsets: Vec<Vec<usize>>,
+    contents: &'a str,
+    offsets: OnceCell<Vec<Vec<usize>>>,
 }

 impl<'a> SourceCodeLocator<'a> {
-    pub fn new(content: &'a str) -> Self {
+    pub fn new(contents: &'a str) -> Self {
        SourceCodeLocator {
-            content,
-            offsets: Self::compute_offsets(content),
+            contents,
+            offsets: OnceCell::new(),
        }
    }

    fn compute_offsets(content: &str) -> Vec<Vec<usize>> {
-        let mut offsets = vec![];
-        let mut offset = 0;
-        for line in content.lines() {
-            let mut newline = 0;
-            let mut line_offsets: Vec<usize> = vec![];
-            for (i, char) in line.char_indices() {
-                line_offsets.push(offset + i);
-                newline = i + char.len_utf8();
+        let mut offsets = vec![vec![]];
+        let mut line_index = 0;
+        for (i, char) in content.char_indices() {
+            offsets[line_index].push(i);
+            if char == '\n' {
+                line_index += 1;
+                offsets.push(vec![]);
            }
-            line_offsets.push(offset + newline);
-            offsets.push(line_offsets);
-            offset += newline + 1;
        }
-        offsets.push(vec![offset]);
        offsets
    }

+    fn get_or_init_offsets(&self) -> &Vec<Vec<usize>> {
+        self.offsets
+            .get_or_init(|| Self::compute_offsets(self.contents))
+    }
+
    pub fn slice_source_code_at(&self, location: &Location) -> &'a str {
-        let offset = self.offsets[location.row() - 1][location.column() - 1];
-        &self.content[offset..]
+        let offsets = self.get_or_init_offsets();
+        let offset = offsets[location.row() - 1][location.column() - 1];
+        &self.contents[offset..]
    }

    pub fn slice_source_code_range(&self, range: &Range) -> &'a str {
-        let start = self.offsets[range.location.row() - 1][range.location.column() - 1];
-        let end = self.offsets[range.end_location.row() - 1][range.end_location.column() - 1];
-        &self.content[start..end]
+        let offsets = self.get_or_init_offsets();
+        let start = offsets[range.location.row() - 1][range.location.column() - 1];
+        let end = offsets[range.end_location.row() - 1][range.end_location.column() - 1];
+        &self.contents[start..end]
    }

    pub fn partition_source_code_at(
@@ -166,14 +169,15 @@ impl<'a> SourceCodeLocator<'a> {
        outer: &Range,
        inner: &Range,
    ) -> (&'a str, &'a str, &'a str) {
-        let outer_start = self.offsets[outer.location.row() - 1][outer.location.column() - 1];
-        let outer_end = self.offsets[outer.end_location.row() - 1][outer.end_location.column() - 1];
-        let inner_start = self.offsets[inner.location.row() - 1][inner.location.column() - 1];
-        let inner_end = self.offsets[inner.end_location.row() - 1][inner.end_location.column() - 1];
+        let offsets = self.get_or_init_offsets();
+        let outer_start = offsets[outer.location.row() - 1][outer.location.column() - 1];
+        let outer_end = offsets[outer.end_location.row() - 1][outer.end_location.column() - 1];
+        let inner_start = offsets[inner.location.row() - 1][inner.location.column() - 1];
+        let inner_end = offsets[inner.end_location.row() - 1][inner.end_location.column() - 1];
        (
-            &self.content[outer_start..inner_start],
-            &self.content[inner_start..inner_end],
-            &self.content[inner_end..outer_end],
+            &self.contents[outer_start..inner_start],
+            &self.contents[inner_start..inner_end],
+            &self.contents[inner_end..outer_end],
        )
    }
 }
@@ -184,15 +188,21 @@ mod tests {

    #[test]
    fn source_code_locator_init() {
+        let content = "x = 1\ny = 2\nz = x + y\n";
+        let locator = SourceCodeLocator::new(content);
+        let offsets = locator.get_or_init_offsets();
+        assert_eq!(offsets.len(), 4);
+        assert_eq!(offsets[0], [0, 1, 2, 3, 4, 5]);
+        assert_eq!(offsets[1], [6, 7, 8, 9, 10, 11]);
+        assert_eq!(offsets[2], [12, 13, 14, 15, 16, 17, 18, 19, 20, 21]);
+        assert!(offsets[3].is_empty());
+
        let content = "# \u{4e9c}\nclass Foo:\n    \"\"\".\"\"\"";
        let locator = SourceCodeLocator::new(content);
-        assert_eq!(locator.offsets.len(), 4);
-        assert_eq!(locator.offsets[0], [0, 1, 2, 5]);
-        assert_eq!(locator.offsets[1], [6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16]);
-        assert_eq!(
-            locator.offsets[2],
-            [17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28]
-        );
-        assert_eq!(locator.offsets[3], [29]);
+        let offsets = locator.get_or_init_offsets();
+        assert_eq!(offsets.len(), 3);
+        assert_eq!(offsets[0], [0, 1, 2, 5]);
+        assert_eq!(offsets[1], [6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16]);
+        assert_eq!(offsets[2], [17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27]);
    }
 }
--- a/src/check_ast.rs
+++ b/src/check_ast.rs
@@ -5,7 +5,6 @@ use std::ops::Deref;
 use std::path::Path;

 use log::error;
-use once_cell::unsync::OnceCell;
 use rustpython_parser::ast::{
    Arg, Arguments, Constant, Excepthandler, ExcepthandlerKind, Expr, ExprContext, ExprKind,
    KeywordData, Operator, Stmt, StmtKind, Suite,
@@ -26,7 +25,8 @@ 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,
@@ -38,13 +38,11 @@ pub const GLOBAL_SCOPE_INDEX: usize = 0;
 pub struct Checker<'a> {
    // Input data.
    path: &'a Path,
-    content: &'a str,
    autofix: &'a fixer::Mode,
    pub(crate) settings: &'a Settings,
+    pub(crate) locator: &'a SourceCodeLocator<'a>,
    // Computed checks.
    checks: Vec<Check>,
-    // Efficient source-code slicing.
-    locator: OnceCell<SourceCodeLocator<'a>>,
    // Docstring tracking.
    docstrings: Vec<(Definition<'a>, Visibility)>,
    // Edit tracking.
@@ -78,14 +76,13 @@ impl<'a> Checker<'a> {
        settings: &'a Settings,
        autofix: &'a fixer::Mode,
        path: &'a Path,
-        content: &'a str,
+        locator: &'a SourceCodeLocator,
    ) -> Checker<'a> {
        Checker {
            settings,
            autofix,
            path,
-            content,
-            locator: OnceCell::new(),
+            locator,
            checks: Default::default(),
            docstrings: Default::default(),
            deletions: Default::default(),
@@ -113,12 +110,6 @@ impl<'a> Checker<'a> {
        }
    }

-    /// Get access to a lazily-initialized `SourceCodeLocator` for the file contents.
-    pub fn get_locator(&self) -> &SourceCodeLocator {
-        self.locator
-            .get_or_init(|| SourceCodeLocator::new(self.content))
-    }
-
    /// Return `true` if a patch should be generated under the given autofix `Mode`.
    pub fn patch(&self) -> bool {
        self.autofix.patch()
@@ -235,7 +226,11 @@ where
                }

                if self.settings.enabled.contains(&CheckCode::N802) {
-                    if let Some(check) = pep8_naming::checks::invalid_function_name(stmt, name) {
+                    if let Some(check) = pep8_naming::checks::invalid_function_name(
+                        stmt,
+                        name,
+                        &self.settings.pep8_naming,
+                    ) {
                        self.checks.push(check);
                    }
                }
@@ -246,6 +241,7 @@ where
                            self.current_scope(),
                            decorator_list,
                            args,
+                            &self.settings.pep8_naming,
                        )
                    {
                        self.checks.push(check);
@@ -257,6 +253,7 @@ where
                        self.current_scope(),
                        decorator_list,
                        args,
+                        &self.settings.pep8_naming,
                    ) {
                        self.checks.push(check);
                    }
@@ -362,6 +359,14 @@ where
                    }
                }

+                if self.settings.enabled.contains(&CheckCode::N818) {
+                    if let Some(check) =
+                        pep8_naming::checks::error_suffix_on_exception_name(stmt, bases, name)
+                    {
+                        self.checks.push(check);
+                    }
+                }
+
                self.check_builtin_shadowing(
                    name,
                    self.locate_check(Range::from_located(stmt)),
@@ -705,6 +710,9 @@ where
                {
                    flake8_bugbear::plugins::duplicate_exceptions(self, stmt, handlers);
                }
+                if self.settings.enabled.contains(&CheckCode::B013) {
+                    flake8_bugbear::plugins::redundant_tuple_in_exception_handler(self, handlers);
+                }
            }
            StmtKind::Assign { targets, value, .. } => {
                if self.settings.enabled.contains(&CheckCode::E731) {
@@ -1798,6 +1806,30 @@ impl<'a> Checker<'a> {
                }
            }

+            if self.settings.enabled.contains(&CheckCode::N806) {
+                if let Some(check) =
+                    pep8_naming::checks::non_lowercase_variable_in_function(current, expr, id)
+                {
+                    self.checks.push(check);
+                }
+            }
+
+            if self.settings.enabled.contains(&CheckCode::N815) {
+                if let Some(check) =
+                    pep8_naming::checks::mixed_case_variable_in_class_scope(current, expr, id)
+                {
+                    self.checks.push(check);
+                }
+            }
+
+            if self.settings.enabled.contains(&CheckCode::N816) {
+                if let Some(check) =
+                    pep8_naming::checks::mixed_case_variable_in_global_scope(current, expr, id)
+                {
+                    self.checks.push(check);
+                }
+            }
+
            if matches!(parent.node, StmtKind::AnnAssign { value: None, .. }) {
                self.add_binding(
                    id.to_string(),
@@ -2104,7 +2136,7 @@ impl<'a> Checker<'a> {
                            ImportKind::ImportFrom => pyflakes::fixes::remove_unused_import_froms,
                        };

-                        match removal_fn(self.get_locator(), &full_names, child, parent, &deleted) {
+                        match removal_fn(self.locator, &full_names, child, parent, &deleted) {
                            Ok(fix) => Some(fix),
                            Err(e) => {
                                error!("Failed to fix unused imports: {}", e);
@@ -2115,15 +2147,27 @@ 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);
                }
            }
        }
@@ -2252,12 +2296,12 @@ impl<'a> Checker<'a> {

 pub fn check_ast(
    python_ast: &Suite,
-    contents: &str,
+    locator: &SourceCodeLocator,
    settings: &Settings,
    autofix: &fixer::Mode,
    path: &Path,
 ) -> Vec<Check> {
-    let mut checker = Checker::new(settings, autofix, path, contents);
+    let mut checker = Checker::new(settings, autofix, path, locator);
    checker.push_scope(Scope::new(ScopeKind::Module));
    checker.bind_builtins();

--- a/src/check_lines.rs
+++ b/src/check_lines.rs
@@ -229,7 +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;

@@ -243,9 +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,
            );
--- a/src/check_tokens.rs
+++ b/src/check_tokens.rs
@@ -1,123 +1,50 @@
 //! Lint rules based on token traversal.

-use rustpython_ast::Location;
 use rustpython_parser::lexer::{LexResult, Tok};

 use crate::ast::operations::SourceCodeLocator;
-use crate::ast::types::Range;
-use crate::checks::{Check, CheckCode, CheckKind};
-use crate::Settings;
-
-// 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 {
-    if text.len() >= 3 {
-        let triple = &text[text.len() - 3..];
-        if triple == "'''" || triple == "\"\"\"" {
-            return triple;
-        }
-    }
-
-    if !text.is_empty() {
-        let single = &text[text.len() - 1..];
-        if single == "'" || single == "\"" {
-            return single;
-        }
-    }
-
-    panic!("Unable to find quotation mark for String token.")
-}
-
-/// W605
-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
-}
+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,
+    locator: &SourceCodeLocator,
    tokens: &[LexResult],
    settings: &Settings,
 ) {
-    // TODO(charlie): Use a shared SourceCodeLocator between this site and the AST traversal.
-    let locator = SourceCodeLocator::new(contents);
    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);
+
+    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(invalid_escape_sequence(&locator, start, end));
+                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);
+                    }
+                }
            }
        }
    }
--- a/src/checks.rs
+++ b/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(
@@ -79,6 +80,7 @@ pub enum CheckCode {
    B002,
    B007,
    B011,
+    B013,
    B014,
    B017,
    B025,
@@ -102,6 +104,11 @@ pub enum CheckCode {
    // flake8-print
    T201,
    T203,
+    // flake8-quotes
+    Q000,
+    Q001,
+    Q002,
+    Q003,
    // pyupgrade
    U001,
    U002,
@@ -162,12 +169,16 @@ pub enum CheckCode {
    N803,
    N804,
    N805,
+    N806,
    N807,
    N811,
    N812,
    N813,
    N814,
+    N815,
+    N816,
    N817,
+    N818,
    // Meta
    M001,
 }
@@ -184,6 +195,7 @@ pub enum CheckCategory {
    Flake8Bugbear,
    Flake8Builtins,
    Flake8Print,
+    Flake8Quotes,
    Meta,
 }

@@ -197,6 +209,7 @@ impl CheckCategory {
            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",
@@ -265,7 +278,7 @@ pub enum CheckKind {
    UndefinedExport(String),
    UndefinedLocal(String),
    UndefinedName(String),
-    UnusedImport(Vec<String>),
+    UnusedImport(Vec<String>, bool),
    UnusedVariable(String),
    YieldOutsideFunction,
    // flake8-builtins
@@ -276,6 +289,7 @@ pub enum CheckKind {
    UnaryPrefixIncrement,
    UnusedLoopControlVariable(String),
    DoNotAssertFalse,
+    RedundantTupleInExceptionHandler(String),
    DuplicateHandlerException(Vec<String>),
    NoAssertRaisesException,
    DuplicateTryBlockException(String),
@@ -299,6 +313,11 @@ pub enum CheckKind {
    // flake8-print
    PrintFound,
    PPrintFound,
+    // flake8-quotes
+    BadQuotesInlineString(Quote),
+    BadQuotesMultilineString(Quote),
+    BadQuotesDocstring(Quote),
+    AvoidQuoteEscape,
    // pyupgrade
    TypeOfPrimitive(Primitive),
    UnnecessaryAbspath,
@@ -359,12 +378,16 @@ pub enum CheckKind {
    InvalidArgumentName(String),
    InvalidFirstArgumentNameForClassMethod,
    InvalidFirstArgumentNameForMethod,
+    NonLowercaseVariableInFunction(String),
    DunderFunctionName,
    ConstantImportedAsNonConstant(String, String),
    LowercaseImportedAsNonLowercase(String, String),
    CamelcaseImportedAsLowercase(String, String),
    CamelcaseImportedAsConstant(String, String),
+    MixedCaseVariableInClassScope(String),
+    MixedCaseVariableInGlobalScope(String),
    CamelcaseImportedAsAcronym(String, String),
+    ErrorSuffixOnExceptionName(String),
    // Meta
    UnusedNOQA(Option<Vec<String>>),
 }
@@ -374,7 +397,11 @@ impl CheckCode {
    pub fn lint_source(&self) -> &'static LintSource {
        match self {
            CheckCode::E501 | CheckCode::W292 | CheckCode::M001 => &LintSource::Lines,
-            CheckCode::W605 => &LintSource::Tokens,
+            CheckCode::W605
+            | CheckCode::Q000
+            | CheckCode::Q001
+            | CheckCode::Q002
+            | CheckCode::Q003 => &LintSource::Tokens,
            CheckCode::E902 => &LintSource::FileSystem,
            _ => &LintSource::AST,
        }
@@ -402,7 +429,7 @@ impl CheckCode {
            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,
@@ -440,6 +467,9 @@ impl CheckCode {
            CheckCode::B002 => CheckKind::UnaryPrefixIncrement,
            CheckCode::B007 => CheckKind::UnusedLoopControlVariable("i".to_string()),
            CheckCode::B011 => CheckKind::DoNotAssertFalse,
+            CheckCode::B013 => {
+                CheckKind::RedundantTupleInExceptionHandler("ValueError".to_string())
+            }
            CheckCode::B014 => CheckKind::DuplicateHandlerException(vec!["ValueError".to_string()]),
            CheckCode::B017 => CheckKind::NoAssertRaisesException,
            CheckCode::B025 => CheckKind::DuplicateTryBlockException("Exception".to_string()),
@@ -476,6 +506,11 @@ 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,
@@ -545,6 +580,7 @@ impl CheckCode {
            CheckCode::N803 => CheckKind::InvalidArgumentName("...".to_string()),
            CheckCode::N804 => CheckKind::InvalidFirstArgumentNameForClassMethod,
            CheckCode::N805 => CheckKind::InvalidFirstArgumentNameForMethod,
+            CheckCode::N806 => CheckKind::NonLowercaseVariableInFunction("...".to_string()),
            CheckCode::N807 => CheckKind::DunderFunctionName,
            CheckCode::N811 => {
                CheckKind::ConstantImportedAsNonConstant("...".to_string(), "...".to_string())
@@ -558,9 +594,12 @@ impl CheckCode {
            CheckCode::N814 => {
                CheckKind::CamelcaseImportedAsConstant("...".to_string(), "...".to_string())
            }
+            CheckCode::N815 => CheckKind::MixedCaseVariableInClassScope("mixedCase".to_string()),
+            CheckCode::N816 => CheckKind::MixedCaseVariableInGlobalScope("mixedCase".to_string()),
            CheckCode::N817 => {
                CheckKind::CamelcaseImportedAsAcronym("...".to_string(), "...".to_string())
            }
+            CheckCode::N818 => CheckKind::ErrorSuffixOnExceptionName("...".to_string()),
            // Meta
            CheckCode::M001 => CheckKind::UnusedNOQA(None),
        }
@@ -618,6 +657,7 @@ impl CheckCode {
            CheckCode::B002 => CheckCategory::Flake8Bugbear,
            CheckCode::B007 => CheckCategory::Flake8Bugbear,
            CheckCode::B011 => CheckCategory::Flake8Bugbear,
+            CheckCode::B013 => CheckCategory::Flake8Bugbear,
            CheckCode::B014 => CheckCategory::Flake8Bugbear,
            CheckCode::B017 => CheckCategory::Flake8Bugbear,
            CheckCode::B025 => CheckCategory::Flake8Bugbear,
@@ -639,6 +679,10 @@ 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,
@@ -696,12 +740,16 @@ impl CheckCode {
            CheckCode::N803 => CheckCategory::PEP8Naming,
            CheckCode::N804 => CheckCategory::PEP8Naming,
            CheckCode::N805 => CheckCategory::PEP8Naming,
+            CheckCode::N806 => CheckCategory::PEP8Naming,
            CheckCode::N807 => CheckCategory::PEP8Naming,
            CheckCode::N811 => CheckCategory::PEP8Naming,
            CheckCode::N812 => CheckCategory::PEP8Naming,
            CheckCode::N813 => CheckCategory::PEP8Naming,
            CheckCode::N814 => CheckCategory::PEP8Naming,
+            CheckCode::N815 => CheckCategory::PEP8Naming,
+            CheckCode::N816 => CheckCategory::PEP8Naming,
            CheckCode::N817 => CheckCategory::PEP8Naming,
+            CheckCode::N818 => CheckCategory::PEP8Naming,
            CheckCode::M001 => CheckCategory::Meta,
        }
    }
@@ -751,7 +799,7 @@ 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
@@ -765,6 +813,7 @@ impl CheckKind {
            CheckKind::UnaryPrefixIncrement => &CheckCode::B002,
            CheckKind::UnusedLoopControlVariable(_) => &CheckCode::B007,
            CheckKind::DoNotAssertFalse => &CheckCode::B011,
+            CheckKind::RedundantTupleInExceptionHandler(_) => &CheckCode::B013,
            CheckKind::DuplicateHandlerException(_) => &CheckCode::B014,
            CheckKind::NoAssertRaisesException => &CheckCode::B017,
            CheckKind::DuplicateTryBlockException(_) => &CheckCode::B025,
@@ -788,6 +837,11 @@ 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,
@@ -848,12 +902,16 @@ impl CheckKind {
            CheckKind::InvalidArgumentName(_) => &CheckCode::N803,
            CheckKind::InvalidFirstArgumentNameForClassMethod => &CheckCode::N804,
            CheckKind::InvalidFirstArgumentNameForMethod => &CheckCode::N805,
+            CheckKind::NonLowercaseVariableInFunction(..) => &CheckCode::N806,
            CheckKind::DunderFunctionName => &CheckCode::N807,
            CheckKind::ConstantImportedAsNonConstant(..) => &CheckCode::N811,
            CheckKind::LowercaseImportedAsNonLowercase(..) => &CheckCode::N812,
            CheckKind::CamelcaseImportedAsLowercase(..) => &CheckCode::N813,
            CheckKind::CamelcaseImportedAsConstant(..) => &CheckCode::N814,
+            CheckKind::MixedCaseVariableInClassScope(..) => &CheckCode::N815,
+            CheckKind::MixedCaseVariableInGlobalScope(..) => &CheckCode::N816,
            CheckKind::CamelcaseImportedAsAcronym(..) => &CheckCode::N817,
+            CheckKind::ErrorSuffixOnExceptionName(..) => &CheckCode::N818,
            // Meta
            CheckKind::UnusedNOQA(_) => &CheckCode::M001,
        }
@@ -980,9 +1038,13 @@ 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")
@@ -1010,6 +1072,9 @@ impl CheckKind {
                "Do not `assert False` (`python -O` removes these calls), raise `AssertionError()`"
                    .to_string()
            }
+            CheckKind::RedundantTupleInExceptionHandler(name) => {
+                format!("A length-one tuple literal is redundant. Write `except {name}:` instead of `except ({name},):`.")
+            }
            CheckKind::DuplicateHandlerException(names) => {
                if names.len() == 1 {
                    let name = &names[0];
@@ -1085,7 +1150,7 @@ impl CheckKind {
                format!("Unnecessary subscript reversal of iterable within `{func}()`")
            }
            CheckKind::UnnecessaryComprehension(obj_type) => {
-                format!(" Unnecessary `{obj_type}` comprehension (rewrite using `{obj_type}()`)")
+                format!("Unnecessary `{obj_type}` comprehension (rewrite using `{obj_type}()`)")
            }
            CheckKind::UnnecessaryMap(obj_type) => {
                if obj_type == "generator" {
@@ -1097,6 +1162,26 @@ 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())
@@ -1250,6 +1335,9 @@ impl CheckKind {
            CheckKind::InvalidFirstArgumentNameForMethod => {
                "First argument of a method should be named `self`".to_string()
            }
+            CheckKind::NonLowercaseVariableInFunction(name) => {
+                format!("Variable `{name}` in function should be lowercase")
+            }
            CheckKind::DunderFunctionName => {
                "Function name should not start and end with `__`".to_string()
            }
@@ -1265,9 +1353,18 @@ impl CheckKind {
            CheckKind::CamelcaseImportedAsConstant(name, asname) => {
                format!("Camelcase `{name}` imported as constant `{asname}`")
            }
+            CheckKind::MixedCaseVariableInClassScope(name) => {
+                format!("Variable `{name}` in class scope should not be mixedCase")
+            }
+            CheckKind::MixedCaseVariableInGlobalScope(name) => {
+                format!("Variable `{name}` in global scope should not be mixedCase")
+            }
            CheckKind::CamelcaseImportedAsAcronym(name, asname) => {
                format!("Camelcase `{name}` imported as acronym `{asname}`")
            }
+            CheckKind::ErrorSuffixOnExceptionName(name) => {
+                format!("Exception name `{name}` should be named with an Error suffix")
+            }
            // Meta
            CheckKind::UnusedNOQA(codes) => match codes {
                None => "Unused `noqa` directive".to_string(),
@@ -1338,7 +1435,7 @@ impl CheckKind {
                | CheckKind::SuperCallWithParameters
                | CheckKind::TypeOfPrimitive(_)
                | CheckKind::UnnecessaryAbspath
-                | CheckKind::UnusedImport(_)
+                | CheckKind::UnusedImport(_, false)
                | CheckKind::UnusedLoopControlVariable(_)
                | CheckKind::UnusedNOQA(_)
                | CheckKind::UsePEP585Annotation(_)
--- a/src/checks_gen.rs
+++ b/src/checks_gen.rs
--- a/src/cli.rs
+++ b/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.")]
@@ -43,16 +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>,
@@ -106,10 +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 {
@@ -117,7 +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 {}",
@@ -131,7 +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 {}",
--- a/src/docstrings/helpers.rs
+++ b/src/docstrings/helpers.rs
@@ -27,7 +27,7 @@ pub fn leading_space(line: &str) -> String {
 /// Extract the leading indentation from a docstring.
 pub fn indentation<'a>(checker: &'a Checker, docstring: &Expr) -> &'a str {
    let range = Range::from_located(docstring);
-    checker.get_locator().slice_source_code_range(&Range {
+    checker.locator.slice_source_code_range(&Range {
        location: Location::new(range.location.row(), 1),
        end_location: Location::new(range.location.row(), range.location.column()),
    })
--- a/src/flake8_bugbear/plugins/mod.rs
+++ b/src/flake8_bugbear/plugins/mod.rs
@@ -2,11 +2,13 @@ pub use assert_false::assert_false;
 pub use assert_raises_exception::assert_raises_exception;
 pub use duplicate_exceptions::duplicate_exceptions;
 pub use duplicate_exceptions::duplicate_handler_exceptions;
+pub use redundant_tuple_in_exception_handler::redundant_tuple_in_exception_handler;
 pub use unary_prefix_increment::unary_prefix_increment;
 pub use unused_loop_control_variable::unused_loop_control_variable;

 mod assert_false;
 mod assert_raises_exception;
 mod duplicate_exceptions;
+mod redundant_tuple_in_exception_handler;
 mod unary_prefix_increment;
 mod unused_loop_control_variable;
--- a/src/flake8_bugbear/plugins/redundant_tuple_in_exception_handler.rs
+++ b/src/flake8_bugbear/plugins/redundant_tuple_in_exception_handler.rs
@@ -0,0 +1,22 @@
+use rustpython_ast::{Excepthandler, ExcepthandlerKind, ExprKind};
+
+use crate::ast::types::{CheckLocator, Range};
+use crate::check_ast::Checker;
+use crate::checks::{Check, CheckKind};
+
+/// B013
+pub fn redundant_tuple_in_exception_handler(checker: &mut Checker, handlers: &[Excepthandler]) {
+    for handler in handlers {
+        let ExcepthandlerKind::ExceptHandler { type_, .. } = &handler.node;
+        if let Some(type_) = type_ {
+            if let ExprKind::Tuple { elts, .. } = &type_.node {
+                if elts.len() == 1 {
+                    checker.add_check(Check::new(
+                        CheckKind::RedundantTupleInExceptionHandler(elts[0].to_string()),
+                        checker.locate_check(Range::from_located(type_)),
+                    ));
+                }
+            }
+        }
+    }
+}
--- a/src/flake8_comprehensions/checks.rs
+++ b/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(
--- a/src/flake8_quotes/checks.rs
+++ b/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(())
+    }
+}
--- a/src/flake8_quotes/docstring_detection.rs
+++ b/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
+    }
+}
--- a/src/flake8_quotes/mod.rs
+++ b/src/flake8_quotes/mod.rs
@@ -0,0 +1,3 @@
+pub mod checks;
+pub mod docstring_detection;
+pub mod settings;
--- a/src/flake8_quotes/settings.rs
+++ b/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_options(options: Options) -> Self {
+        Self {
+            inline_quotes: options.inline_quotes.unwrap_or(Quote::Single),
+            multiline_quotes: options.multiline_quotes.unwrap_or(Quote::Double),
+            docstring_quotes: options.docstring_quotes.unwrap_or(Quote::Double),
+            avoid_escape: options.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,
+        }
+    }
+}
--- a/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__double_docstring_docstring_doubles.py.snap
+++ b/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__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: ~
+
--- a/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__double_docstring_docstring_doubles_class.py.snap
+++ b/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__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: ~
+
--- a/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__double_docstring_docstring_doubles_function.py.snap
+++ b/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__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: ~
+
--- a/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__double_docstring_docstring_doubles_module_multiline.py.snap
+++ b/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__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: ~
+
--- a/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__double_docstring_docstring_doubles_module_singleline.py.snap
+++ b/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__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: ~
+
--- a/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__double_docstring_docstring_singles.py.snap
+++ b/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__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: ~
+
--- a/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__double_docstring_docstring_singles_class.py.snap
+++ b/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__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: ~
+
--- a/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__double_docstring_docstring_singles_function.py.snap
+++ b/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__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: ~
+
--- a/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__double_docstring_docstring_singles_module_multiline.py.snap
+++ b/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__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: ~
+
--- a/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__double_docstring_docstring_singles_module_singleline.py.snap
+++ b/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__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: ~
+
--- a/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__doubles_doubles.py.snap
+++ b/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__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: ~
+
--- a/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__doubles_doubles_escaped.py.snap
+++ b/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__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: ~
+
--- a/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__doubles_doubles_multiline_string.py.snap
+++ b/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__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: ~
+
--- a/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__doubles_doubles_noqa.py.snap
+++ b/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__doubles_doubles_noqa.py.snap
@@ -0,0 +1,6 @@
+---
+source: src/flake8_quotes/checks.rs
+expression: checks
+---
+[]
+
--- a/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__doubles_doubles_wrapped.py.snap
+++ b/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__doubles_doubles_wrapped.py.snap
@@ -0,0 +1,6 @@
+---
+source: src/flake8_quotes/checks.rs
+expression: checks
+---
+[]
+
--- a/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__single_docstring_docstring_doubles.py.snap
+++ b/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__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: ~
+
--- a/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__single_docstring_docstring_doubles_class.py.snap
+++ b/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__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: ~
+
--- a/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__single_docstring_docstring_doubles_function.py.snap
+++ b/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__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: ~
+
--- a/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__single_docstring_docstring_doubles_module_multiline.py.snap
+++ b/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__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: ~
+
--- a/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__single_docstring_docstring_doubles_module_singleline.py.snap
+++ b/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__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: ~
+
--- a/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__single_docstring_docstring_singles.py.snap
+++ b/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__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: ~
+
--- a/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__single_docstring_docstring_singles_class.py.snap
+++ b/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__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: ~
+
--- a/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__single_docstring_docstring_singles_function.py.snap
+++ b/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__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: ~
+
--- a/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__single_docstring_docstring_singles_module_multiline.py.snap
+++ b/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__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: ~
+
--- a/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__single_docstring_docstring_singles_module_singleline.py.snap
+++ b/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__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: ~
+
--- a/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__singles_singles.py.snap
+++ b/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__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: ~
+
--- a/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__singles_singles_escaped.py.snap
+++ b/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__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: ~
+
--- a/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__singles_singles_multiline_string.py.snap
+++ b/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__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: ~
+
--- a/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__singles_singles_noqa.py.snap
+++ b/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__singles_singles_noqa.py.snap
@@ -0,0 +1,6 @@
+---
+source: src/flake8_quotes/checks.rs
+expression: checks
+---
+[]
+
--- a/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__singles_singles_wrapped.py.snap
+++ b/src/flake8_quotes/snapshots/ruff__flake8_quotescheckstests__singles_singles_wrapped.py.snap
@@ -0,0 +1,6 @@
+---
+source: src/flake8_quotes/checks.rs
+expression: checks
+---
+[]
+
--- a/src/fs.rs
+++ b/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() {
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -6,10 +6,13 @@ 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;
@@ -18,6 +21,7 @@ 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;
@@ -26,6 +30,7 @@ mod flake8_bugbear;
 mod flake8_builtins;
 mod flake8_comprehensions;
 mod flake8_print;
+mod flake8_quotes;
 pub mod fs;
 pub mod linter;
 pub mod logging;
@@ -36,14 +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, quiet: bool) -> Result<Vec<Message>> {
+pub fn check(path: &Path, contents: &str) -> Result<Vec<Message>> {
    // Find the project root and pyproject.toml.
    let project_root = pyproject::find_project_root(&[path.to_path_buf()]);
    match &project_root {
@@ -56,11 +60,8 @@ pub fn check(path: &Path, contents: &str, quiet: bool) -> Result<Vec<Message>> {
        None => debug!("Unable to find pyproject.toml; using default settings..."),
    };

-    let settings = Settings::from_raw(RawSettings::from_pyproject(
-        &pyproject,
-        &project_root,
-        quiet,
-    )?);
+    let settings =
+        Settings::from_configuration(Configuration::from_pyproject(&pyproject, &project_root)?);

    // Tokenize once.
    let tokens: Vec<LexResult> = tokenize(contents);
--- a/src/linter.rs
+++ b/src/linter.rs
@@ -9,6 +9,7 @@ use log::debug;
 use rustpython_parser::lexer::LexResult;
 use rustpython_parser::{lexer, parser};

+use crate::ast::operations::SourceCodeLocator;
 use crate::ast::types::Range;
 use crate::autofix::fixer;
 use crate::autofix::fixer::fix_file;
@@ -46,13 +47,16 @@ pub(crate) fn check_path(
    // Aggregate all checks.
    let mut checks: Vec<Check> = vec![];

+    // Initialize the SourceCodeLocator (which computes offsets lazily).
+    let locator = SourceCodeLocator::new(contents);
+
    // 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);
+        check_tokens(&mut checks, &locator, &tokens, settings);
    }

    // Run the AST-based checks.
@@ -63,7 +67,7 @@ pub(crate) fn check_path(
    {
        match parser::parse_program_tokens(tokens, "<filename>") {
            Ok(python_ast) => {
-                checks.extend(check_ast(&python_ast, contents, settings, autofix, path))
+                checks.extend(check_ast(&python_ast, &locator, settings, autofix, path))
            }
            Err(parse_error) => {
                if settings.enabled.contains(&CheckCode::E999) {
@@ -236,16 +240,12 @@ 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);
@@ -258,6 +258,7 @@ mod tests {
    #[test_case(CheckCode::B002, Path::new("B002.py"); "B002")]
    #[test_case(CheckCode::B007, Path::new("B007.py"); "B007")]
    #[test_case(CheckCode::B011, Path::new("B011.py"); "B011")]
+    #[test_case(CheckCode::B013, Path::new("B013.py"); "B013")]
    #[test_case(CheckCode::B014, Path::new("B014.py"); "B014")]
    #[test_case(CheckCode::B017, Path::new("B017.py"); "B017")]
    #[test_case(CheckCode::B025, Path::new("B025.py"); "B025")]
@@ -372,12 +373,16 @@ mod tests {
    #[test_case(CheckCode::N803, Path::new("N803.py"); "N803")]
    #[test_case(CheckCode::N804, Path::new("N804.py"); "N804")]
    #[test_case(CheckCode::N805, Path::new("N805.py"); "N805")]
+    #[test_case(CheckCode::N806, Path::new("N806.py"); "N806")]
    #[test_case(CheckCode::N807, Path::new("N807.py"); "N807")]
    #[test_case(CheckCode::N811, Path::new("N811.py"); "N811")]
    #[test_case(CheckCode::N812, Path::new("N812.py"); "N812")]
    #[test_case(CheckCode::N813, Path::new("N813.py"); "N813")]
    #[test_case(CheckCode::N814, Path::new("N814.py"); "N814")]
+    #[test_case(CheckCode::N815, Path::new("N815.py"); "N815")]
+    #[test_case(CheckCode::N816, Path::new("N816.py"); "N816")]
    #[test_case(CheckCode::N817, Path::new("N817.py"); "N817")]
+    #[test_case(CheckCode::N818, Path::new("N818.py"); "N818")]
    #[test_case(CheckCode::T201, Path::new("T201.py"); "T201")]
    #[test_case(CheckCode::T203, Path::new("T203.py"); "T203")]
    #[test_case(CheckCode::U001, Path::new("U001.py"); "U001")]
--- a/src/main.rs
+++ b/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)
    );
 }

@@ -256,15 +261,15 @@ fn inner_main() -> Result<ExitCode> {
        .map(|pair| PerFileIgnore::new(pair, &project_root))
        .collect();

-    let mut settings = RawSettings::from_pyproject(&pyproject, &project_root, cli.quiet)?;
+    let mut configuration = Configuration::from_pyproject(&pyproject, &project_root)?;
    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(
@@ -272,10 +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(
@@ -283,22 +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 {
@@ -306,11 +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);
--- a/src/noqa.rs
+++ b/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(
--- a/src/pep8_naming/checks.rs
+++ b/src/pep8_naming/checks.rs
@@ -1,9 +1,11 @@
 use itertools::Itertools;
 use rustpython_ast::{Arguments, Expr, ExprKind, Stmt};

-use crate::ast::types::{Range, Scope, ScopeKind};
+use crate::ast::types::{FunctionScope, Range, Scope, ScopeKind};
 use crate::checks::{Check, CheckKind};
+use crate::pep8_naming::settings::Settings;

+/// N801
 pub fn invalid_class_name(class_def: &Stmt, name: &str) -> Option<Check> {
    let stripped = name.strip_prefix('_').unwrap_or(name);
    if !stripped
@@ -21,8 +23,14 @@ pub fn invalid_class_name(class_def: &Stmt, name: &str) -> Option<Check> {
    None
 }

-pub fn invalid_function_name(func_def: &Stmt, name: &str) -> Option<Check> {
-    if name.chars().any(|c| c.is_uppercase()) {
+/// N802
+pub fn invalid_function_name(func_def: &Stmt, name: &str, settings: &Settings) -> Option<Check> {
+    if !is_lower(name)
+        && !settings
+            .ignore_names
+            .iter()
+            .any(|ignore_name| ignore_name == name)
+    {
        return Some(Check::new(
            CheckKind::InvalidFunctionName(name.to_string()),
            Range::from_located(func_def),
@@ -31,8 +39,9 @@ pub fn invalid_function_name(func_def: &Stmt, name: &str) -> Option<Check> {
    None
 }

+/// N803
 pub fn invalid_argument_name(location: Range, name: &str) -> Option<Check> {
-    if name.chars().any(|c| c.is_uppercase()) {
+    if !is_lower(name) {
        return Some(Check::new(
            CheckKind::InvalidArgumentName(name.to_string()),
            location,
@@ -41,10 +50,12 @@ pub fn invalid_argument_name(location: Range, name: &str) -> Option<Check> {
    None
 }

+/// N804
 pub fn invalid_first_argument_name_for_class_method(
    scope: &Scope,
    decorator_list: &[Expr],
    args: &Arguments,
+    settings: &Settings,
 ) -> Option<Check> {
    if !matches!(scope.kind, ScopeKind::Class) {
        return None;
@@ -52,7 +63,7 @@ pub fn invalid_first_argument_name_for_class_method(

    if decorator_list.iter().any(|decorator| {
        if let ExprKind::Name { id, .. } = &decorator.node {
-            id == "classmethod"
+            settings.classmethod_decorators.contains(id)
        } else {
            false
        }
@@ -69,10 +80,12 @@ pub fn invalid_first_argument_name_for_class_method(
    None
 }

+/// N805
 pub fn invalid_first_argument_name_for_method(
    scope: &Scope,
    decorator_list: &[Expr],
    args: &Arguments,
+    settings: &Settings,
 ) -> Option<Check> {
    if !matches!(scope.kind, ScopeKind::Class) {
        return None;
@@ -80,7 +93,8 @@ pub fn invalid_first_argument_name_for_method(

    if decorator_list.iter().any(|decorator| {
        if let ExprKind::Name { id, .. } = &decorator.node {
-            id == "classmethod" || id == "staticmethod"
+            settings.classmethod_decorators.contains(id)
+                || settings.staticmethod_decorators.contains(id)
        } else {
            false
        }
@@ -99,6 +113,21 @@ pub fn invalid_first_argument_name_for_method(
    None
 }

+/// N806
+pub fn non_lowercase_variable_in_function(scope: &Scope, expr: &Expr, name: &str) -> Option<Check> {
+    if !matches!(scope.kind, ScopeKind::Function(FunctionScope { .. })) {
+        return None;
+    }
+    if !is_lower(name) {
+        return Some(Check::new(
+            CheckKind::NonLowercaseVariableInFunction(name.to_string()),
+            Range::from_located(expr),
+        ));
+    }
+    None
+}
+
+/// N807
 pub fn dunder_function_name(func_def: &Stmt, scope: &Scope, name: &str) -> Option<Check> {
    if matches!(scope.kind, ScopeKind::Class) {
        return None;
@@ -114,6 +143,136 @@ pub fn dunder_function_name(func_def: &Stmt, scope: &Scope, name: &str) -> Optio
    None
 }

+/// N811
+pub fn constant_imported_as_non_constant(
+    import_from: &Stmt,
+    name: &str,
+    asname: &str,
+) -> Option<Check> {
+    if is_upper(name) && !is_upper(asname) {
+        return Some(Check::new(
+            CheckKind::ConstantImportedAsNonConstant(name.to_string(), asname.to_string()),
+            Range::from_located(import_from),
+        ));
+    }
+    None
+}
+
+/// N812
+pub fn lowercase_imported_as_non_lowercase(
+    import_from: &Stmt,
+    name: &str,
+    asname: &str,
+) -> Option<Check> {
+    if is_lower(name) && asname.to_lowercase() != asname {
+        return Some(Check::new(
+            CheckKind::LowercaseImportedAsNonLowercase(name.to_string(), asname.to_string()),
+            Range::from_located(import_from),
+        ));
+    }
+    None
+}
+
+/// N813
+pub fn camelcase_imported_as_lowercase(
+    import_from: &Stmt,
+    name: &str,
+    asname: &str,
+) -> Option<Check> {
+    if is_camelcase(name) && is_lower(asname) {
+        return Some(Check::new(
+            CheckKind::CamelcaseImportedAsLowercase(name.to_string(), asname.to_string()),
+            Range::from_located(import_from),
+        ));
+    }
+    None
+}
+
+/// N814
+pub fn camelcase_imported_as_constant(
+    import_from: &Stmt,
+    name: &str,
+    asname: &str,
+) -> Option<Check> {
+    if is_camelcase(name) && is_upper(asname) && !is_acronym(name, asname) {
+        return Some(Check::new(
+            CheckKind::CamelcaseImportedAsConstant(name.to_string(), asname.to_string()),
+            Range::from_located(import_from),
+        ));
+    }
+    None
+}
+
+/// N815
+pub fn mixed_case_variable_in_class_scope(scope: &Scope, expr: &Expr, name: &str) -> Option<Check> {
+    if !matches!(scope.kind, ScopeKind::Class) {
+        return None;
+    }
+    if is_mixed_case(name) {
+        return Some(Check::new(
+            CheckKind::MixedCaseVariableInClassScope(name.to_string()),
+            Range::from_located(expr),
+        ));
+    }
+    None
+}
+
+/// N816
+pub fn mixed_case_variable_in_global_scope(
+    scope: &Scope,
+    expr: &Expr,
+    name: &str,
+) -> Option<Check> {
+    if !matches!(scope.kind, ScopeKind::Module) {
+        return None;
+    }
+    if is_mixed_case(name) {
+        return Some(Check::new(
+            CheckKind::MixedCaseVariableInGlobalScope(name.to_string()),
+            Range::from_located(expr),
+        ));
+    }
+    None
+}
+
+/// N817
+pub fn camelcase_imported_as_acronym(
+    import_from: &Stmt,
+    name: &str,
+    asname: &str,
+) -> Option<Check> {
+    if is_camelcase(name) && is_upper(asname) && is_acronym(name, asname) {
+        return Some(Check::new(
+            CheckKind::CamelcaseImportedAsAcronym(name.to_string(), asname.to_string()),
+            Range::from_located(import_from),
+        ));
+    }
+    None
+}
+
+/// N818
+pub fn error_suffix_on_exception_name(
+    class_def: &Stmt,
+    bases: &[Expr],
+    name: &str,
+) -> Option<Check> {
+    if bases.iter().any(|base| {
+        if let ExprKind::Name { id, .. } = &base.node {
+            id == "Exception"
+        } else {
+            false
+        }
+    }) {
+        if !name.ends_with("Error") {
+            return Some(Check::new(
+                CheckKind::ErrorSuffixOnExceptionName(name.to_string()),
+                Range::from_located(class_def),
+            ));
+        }
+    }
+    None
+}
+
 fn is_lower(s: &str) -> bool {
    let mut cased = false;
    for c in s.chars() {
@@ -138,86 +297,27 @@ fn is_upper(s: &str) -> bool {
    cased
 }

-pub fn constant_imported_as_non_constant(
-    import_from: &Stmt,
-    name: &str,
-    asname: &str,
-) -> Option<Check> {
-    if is_upper(name) && !is_upper(asname) {
-        return Some(Check::new(
-            CheckKind::ConstantImportedAsNonConstant(name.to_string(), asname.to_string()),
-            Range::from_located(import_from),
-        ));
-    }
-    None
-}
-
-pub fn lowercase_imported_as_non_lowercase(
-    import_from: &Stmt,
-    name: &str,
-    asname: &str,
-) -> Option<Check> {
-    if is_lower(name) && asname.to_lowercase() != asname {
-        return Some(Check::new(
-            CheckKind::LowercaseImportedAsNonLowercase(name.to_string(), asname.to_string()),
-            Range::from_located(import_from),
-        ));
-    }
-    None
-}
-
 fn is_camelcase(name: &str) -> bool {
    !is_lower(name) && !is_upper(name) && !name.contains('_')
 }
+
+fn is_mixed_case(name: &str) -> bool {
+    !is_lower(name)
+        && name
+            .strip_prefix('_')
+            .unwrap_or(name)
+            .chars()
+            .next()
+            .map_or_else(|| false, |c| c.is_lowercase())
+}
+
 fn is_acronym(name: &str, asname: &str) -> bool {
    name.chars().filter(|c| c.is_uppercase()).join("") == asname
 }

-pub fn camelcase_imported_as_lowercase(
-    import_from: &Stmt,
-    name: &str,
-    asname: &str,
-) -> Option<Check> {
-    if is_camelcase(name) && is_lower(asname) {
-        return Some(Check::new(
-            CheckKind::CamelcaseImportedAsLowercase(name.to_string(), asname.to_string()),
-            Range::from_located(import_from),
-        ));
-    }
-    None
-}
-
-pub fn camelcase_imported_as_constant(
-    import_from: &Stmt,
-    name: &str,
-    asname: &str,
-) -> Option<Check> {
-    if is_camelcase(name) && is_upper(asname) && !is_acronym(name, asname) {
-        return Some(Check::new(
-            CheckKind::CamelcaseImportedAsConstant(name.to_string(), asname.to_string()),
-            Range::from_located(import_from),
-        ));
-    }
-    None
-}
-
-pub fn camelcase_imported_as_acronym(
-    import_from: &Stmt,
-    name: &str,
-    asname: &str,
-) -> Option<Check> {
-    if is_camelcase(name) && is_upper(asname) && is_acronym(name, asname) {
-        return Some(Check::new(
-            CheckKind::CamelcaseImportedAsAcronym(name.to_string(), asname.to_string()),
-            Range::from_located(import_from),
-        ));
-    }
-    None
-}
-
 #[cfg(test)]
 mod tests {
-    use super::{is_acronym, is_camelcase, is_lower, is_upper};
+    use super::{is_acronym, is_camelcase, is_lower, is_mixed_case, is_upper};

    #[test]
    fn test_is_lower() -> () {
@@ -251,6 +351,17 @@ mod tests {
        assert!(!is_camelcase("CAMEL_CASE"));
    }

+    #[test]
+    fn test_is_mixed_case() -> () {
+        assert!(is_mixed_case("mixedCase"));
+        assert!(is_mixed_case("mixed_Case"));
+        assert!(is_mixed_case("_mixed_Case"));
+        assert!(!is_mixed_case("mixed_case"));
+        assert!(!is_mixed_case("MIXED_CASE"));
+        assert!(!is_mixed_case(""));
+        assert!(!is_mixed_case("_"));
+    }
+
    #[test]
    fn test_is_acronym() -> () {
        assert!(is_acronym("AB", "AB"));
--- a/src/pep8_naming/mod.rs
+++ b/src/pep8_naming/mod.rs
@@ -1 +1,2 @@
 pub mod checks;
+pub mod settings;
--- a/src/pep8_naming/settings.rs
+++ b/src/pep8_naming/settings.rs
@@ -0,0 +1,63 @@
+//! Settings for the `pep8-naming` plugin.
+
+use serde::Deserialize;
+
+const IGNORE_NAMES: [&str; 12] = [
+    "setUp",
+    "tearDown",
+    "setUpClass",
+    "tearDownClass",
+    "setUpModule",
+    "tearDownModule",
+    "asyncSetUp",
+    "asyncTearDown",
+    "setUpTestData",
+    "failureException",
+    "longMessage",
+    "maxDiff",
+];
+
+const CLASSMETHOD_DECORATORS: [&str; 1] = ["classmethod"];
+
+const STATICMETHOD_DECORATORS: [&str; 1] = ["staticmethod"];
+
+#[derive(Debug, PartialEq, Eq, Deserialize)]
+#[serde(deny_unknown_fields, rename_all = "kebab-case")]
+pub struct Options {
+    pub ignore_names: Option<Vec<String>>,
+    pub classmethod_decorators: Option<Vec<String>>,
+    pub staticmethod_decorators: Option<Vec<String>>,
+}
+
+#[derive(Debug)]
+pub struct Settings {
+    pub ignore_names: Vec<String>,
+    pub classmethod_decorators: Vec<String>,
+    pub staticmethod_decorators: Vec<String>,
+}
+
+impl Settings {
+    pub fn from_options(options: Options) -> Self {
+        Self {
+            ignore_names: options
+                .ignore_names
+                .unwrap_or_else(|| IGNORE_NAMES.map(String::from).to_vec()),
+            classmethod_decorators: options
+                .classmethod_decorators
+                .unwrap_or_else(|| CLASSMETHOD_DECORATORS.map(String::from).to_vec()),
+            staticmethod_decorators: options
+                .staticmethod_decorators
+                .unwrap_or_else(|| STATICMETHOD_DECORATORS.map(String::from).to_vec()),
+        }
+    }
+}
+
+impl Default for Settings {
+    fn default() -> Self {
+        Self {
+            ignore_names: IGNORE_NAMES.map(String::from).to_vec(),
+            classmethod_decorators: CLASSMETHOD_DECORATORS.map(String::from).to_vec(),
+            staticmethod_decorators: STATICMETHOD_DECORATORS.map(String::from).to_vec(),
+        }
+    }
+}
--- a/src/pycodestyle/checks.rs
+++ b/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
+}
--- a/src/pydocstyle/plugins.rs
+++ b/src/pydocstyle/plugins.rs
@@ -162,7 +162,7 @@ pub fn blank_before_after_function(checker: &mut Checker, definition: &Definitio
            } = &docstring.node
            {
                if checker.settings.enabled.contains(&CheckCode::D201) {
-                    let (before, _, _) = checker.get_locator().partition_source_code_at(
+                    let (before, _, _) = checker.locator.partition_source_code_at(
                        &Range::from_located(parent),
                        &Range::from_located(docstring),
                    );
@@ -190,7 +190,7 @@ pub fn blank_before_after_function(checker: &mut Checker, definition: &Definitio
                }

                if checker.settings.enabled.contains(&CheckCode::D202) {
-                    let (_, _, after) = checker.get_locator().partition_source_code_at(
+                    let (_, _, after) = checker.locator.partition_source_code_at(
                        &Range::from_located(parent),
                        &Range::from_located(docstring),
                    );
@@ -253,7 +253,7 @@ pub fn blank_before_after_class(checker: &mut Checker, definition: &Definition)
                if checker.settings.enabled.contains(&CheckCode::D203)
                    || checker.settings.enabled.contains(&CheckCode::D211)
                {
-                    let (before, _, _) = checker.get_locator().partition_source_code_at(
+                    let (before, _, _) = checker.locator.partition_source_code_at(
                        &Range::from_located(parent),
                        &Range::from_located(docstring),
                    );
@@ -300,7 +300,7 @@ pub fn blank_before_after_class(checker: &mut Checker, definition: &Definition)
                }

                if checker.settings.enabled.contains(&CheckCode::D204) {
-                    let (_, _, after) = checker.get_locator().partition_source_code_at(
+                    let (_, _, after) = checker.locator.partition_source_code_at(
                        &Range::from_located(parent),
                        &Range::from_located(docstring),
                    );
@@ -530,7 +530,7 @@ pub fn newline_after_last_paragraph(checker: &mut Checker, definition: &Definiti
                }
                if line_count > 1 {
                    let content = checker
-                        .get_locator()
+                        .locator
                        .slice_source_code_range(&Range::from_located(docstring));
                    if let Some(last_line) = content.lines().last().map(|line| line.trim()) {
                        if last_line != "\"\"\"" && last_line != "'''" {
@@ -583,7 +583,7 @@ pub fn no_surrounding_whitespace(checker: &mut Checker, definition: &Definition)
                    );
                    if checker.patch() {
                        if let Some(first_line) = checker
-                            .get_locator()
+                            .locator
                            .slice_source_code_range(&Range::from_located(docstring))
                            .lines()
                            .next()
@@ -629,7 +629,7 @@ pub fn multi_line_summary_start(checker: &mut Checker, definition: &Definition)
        {
            if string.lines().nth(1).is_some() {
                if let Some(first_line) = checker
-                    .get_locator()
+                    .locator
                    .slice_source_code_range(&Range::from_located(docstring))
                    .lines()
                    .next()
@@ -665,7 +665,7 @@ pub fn triple_quotes(checker: &mut Checker, definition: &Definition) {
        } = &docstring.node
        {
            if let Some(first_line) = checker
-                .get_locator()
+                .locator
                .slice_source_code_range(&Range::from_located(docstring))
                .lines()
                .next()
--- a/src/pyflakes/checks.rs
+++ b/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],
--- a/src/pyupgrade/checks.rs
+++ b/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 {
--- a/src/pyupgrade/plugins/super_call_with_parameters.rs
+++ b/src/pyupgrade/plugins/super_call_with_parameters.rs
@@ -17,9 +17,7 @@ pub fn super_call_with_parameters(checker: &mut Checker, expr: &Expr, func: &Exp
            .collect();
        if let Some(mut check) = checks::super_args(scope, &parents, expr, func, args) {
            if checker.patch() {
-                if let Some(fix) =
-                    pyupgrade::fixes::remove_super_arguments(checker.get_locator(), expr)
-                {
+                if let Some(fix) = pyupgrade::fixes::remove_super_arguments(checker.locator, expr) {
                    check.amend(fix);
                }
            }
--- a/src/pyupgrade/plugins/useless_object_inheritance.rs
+++ b/src/pyupgrade/plugins/useless_object_inheritance.rs
@@ -15,7 +15,7 @@ pub fn useless_object_inheritance(
    if let Some(mut check) = checks::useless_object_inheritance(name, bases, scope) {
        if checker.patch() {
            if let Some(fix) = pyupgrade::fixes::remove_class_def_base(
-                checker.get_locator(),
+                checker.locator,
                &stmt.location,
                check.location,
                bases,
--- a/src/settings.rs
+++ b/src/settings.rs
@@ -1,321 +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>,
-        quiet: bool,
-    ) -> Result<Self> {
-        let config = load_config(pyproject, quiet)?;
-        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::PycodestyleError | 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,
-        }
-    }
-}
--- a/src/settings/configuration.rs
+++ b/src/settings/configuration.rs
@@ -0,0 +1,109 @@
+//! 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::settings::pyproject::load_options;
+use crate::settings::types::{FilePattern, PerFileIgnore, PythonVersion};
+use crate::{flake8_quotes, pep8_naming};
+
+#[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,
+    pub pep8_naming: pep8_naming::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>,
+    ) -> Result<Self> {
+        let options = load_options(pyproject)?;
+        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_options)
+                .unwrap_or_default(),
+            pep8_naming: options
+                .pep8_naming
+                .map(pep8_naming::settings::Settings::from_options)
+                .unwrap_or_default(),
+        })
+    }
+}
--- a/src/settings/mod.rs
+++ b/src/settings/mod.rs
@@ -0,0 +1,165 @@
+//! 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::settings::configuration::Configuration;
+use crate::settings::types::{FilePattern, PerFileIgnore, PythonVersion};
+use crate::{flake8_quotes, pep8_naming};
+
+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,
+    pub pep8_naming: pep8_naming::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,
+            pep8_naming: config.pep8_naming,
+            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]+?))$").unwrap(),
+            enabled: BTreeSet::from([check_code]),
+            exclude: vec![],
+            extend_exclude: vec![],
+            line_length: 88,
+            per_file_ignores: vec![],
+            target_version: PythonVersion::Py310,
+            flake8_quotes: Default::default(),
+            pep8_naming: Default::default(),
+        }
+    }
+
+    pub fn for_rules(check_codes: Vec<CheckCode>) -> Self {
+        Self {
+            dummy_variable_rgx: Regex::new("^(_+|(_+[a-zA-Z0-9_]*[a-zA-Z0-9]+?))$").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(),
+            pep8_naming: 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);
+    }
+}
--- a/src/settings/options.rs
+++ b/src/settings/options.rs
@@ -0,0 +1,30 @@
+//! Options that the user can provide via pyproject.toml.
+
+use serde::Deserialize;
+
+use crate::checks_gen::CheckCodePrefix;
+use crate::settings::types::{PythonVersion, StrCheckCodePair};
+use crate::{flake8_quotes, pep8_naming};
+
+#[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>,
+    // Plugins
+    pub flake8_quotes: Option<flake8_quotes::settings::Options>,
+    pub pep8_naming: Option<pep8_naming::settings::Options>,
+}
--- a/src/settings/pyproject.rs
+++ b/src/settings/pyproject.rs
@@ -1,105 +1,27 @@
+//! Utilities for locating (and extracting configuration from) a pyproject.toml.
+
 use std::path::{Path, PathBuf};
-use std::str::FromStr;

-use anyhow::{anyhow, Result};
+use anyhow::Result;
 use common_path::common_path_all;
+use log::debug;
 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>, quiet: bool) -> Result<Config> {
-    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())
-        }
-    }
-}
-
-#[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())
 }
@@ -148,6 +70,20 @@ pub fn find_project_root(sources: &[PathBuf]) -> Option<PathBuf> {
    None
 }

+pub fn load_options(pyproject: &Option<PathBuf>) -> Result<Options> {
+    match pyproject {
+        Some(pyproject) => Ok(parse_pyproject_toml(pyproject)?
+            .tool
+            .and_then(|tool| tool.ruff)
+            .unwrap_or_default()),
+        None => {
+            debug!("No pyproject.toml found.");
+            debug!("Falling back to default configuration...");
+            Ok(Default::default())
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
    use std::env::current_dir;
@@ -156,26 +92,27 @@ 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::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;
+    use crate::{flake8_quotes, pep8_naming};

    #[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]
@@ -184,7 +121,7 @@ mod tests {
        assert_eq!(
            pyproject.tool,
            Some(Tools {
-                ruff: Some(Config {
+                ruff: Some(Options {
                    line_length: None,
                    exclude: None,
                    extend_exclude: vec![],
@@ -195,11 +132,13 @@ mod tests {
                    per_file_ignores: vec![],
                    dummy_variable_rgx: None,
                    target_version: None,
+                    flake8_quotes: None,
+                    pep8_naming: None,
                })
            })
        );

-        let pyproject: PyProject = toml::from_str(
+        let pyproject: Pyproject = toml::from_str(
            r#"
 [tool.black]
 [tool.ruff]
@@ -209,7 +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![],
@@ -220,11 +159,13 @@ line-length = 79
                    per_file_ignores: vec![],
                    dummy_variable_rgx: None,
                    target_version: None,
+                    flake8_quotes: None,
+                    pep8_naming: None,
                })
            })
        );

-        let pyproject: PyProject = toml::from_str(
+        let pyproject: Pyproject = toml::from_str(
            r#"
 [tool.black]
 [tool.ruff]
@@ -234,7 +175,7 @@ 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![],
@@ -245,11 +186,13 @@ exclude = ["foo.py"]
                    per_file_ignores: vec![],
                    dummy_variable_rgx: None,
                    target_version: None,
+                    flake8_quotes: None,
+                    pep8_naming: None,
                })
            })
        );

-        let pyproject: PyProject = toml::from_str(
+        let pyproject: Pyproject = toml::from_str(
            r#"
 [tool.black]
 [tool.ruff]
@@ -259,22 +202,24 @@ 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,
+                    pep8_naming: None,
                })
            })
        );

-        let pyproject: PyProject = toml::from_str(
+        let pyproject: Pyproject = toml::from_str(
            r#"
 [tool.black]
 [tool.ruff]
@@ -285,22 +230,24 @@ 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,
+                    pep8_naming: None,
                })
            })
        );

-        assert!(toml::from_str::<PyProject>(
+        assert!(toml::from_str::<Pyproject>(
            r#"
 [tool.black]
 [tool.ruff]
@@ -309,7 +256,7 @@ line_length = 79
        )
        .is_err());

-        assert!(toml::from_str::<PyProject>(
+        assert!(toml::from_str::<Pyproject>(
            r#"
 [tool.black]
 [tool.ruff]
@@ -318,7 +265,7 @@ select = ["E123"]
        )
        .is_err());

-        assert!(toml::from_str::<PyProject>(
+        assert!(toml::from_str::<Pyproject>(
            r#"
 [tool.black]
 [tool.ruff]
@@ -350,7 +297,7 @@ other-attribute = 1
            .expect("Unable to find tool.ruff.");
        assert_eq!(
            config,
-            Config {
+            Options {
                line_length: Some(88),
                exclude: None,
                extend_exclude: vec![
@@ -362,9 +309,36 @@ 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),
+                }),
+                pep8_naming: Some(pep8_naming::settings::Options {
+                    ignore_names: Some(vec![
+                        "setUp".to_string(),
+                        "tearDown".to_string(),
+                        "setUpClass".to_string(),
+                        "tearDownClass".to_string(),
+                        "setUpModule".to_string(),
+                        "tearDownModule".to_string(),
+                        "asyncSetUp".to_string(),
+                        "asyncTearDown".to_string(),
+                        "setUpTestData".to_string(),
+                        "failureException".to_string(),
+                        "longMessage".to_string(),
+                        "maxDiff".to_string(),
+                    ]),
+                    classmethod_decorators: Some(vec!["classmethod".to_string()]),
+                    staticmethod_decorators: Some(vec!["staticmethod".to_string()]),
+                }),
            }
        );

@@ -375,6 +349,8 @@ 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");
--- a/src/settings/types.rs
+++ b/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 })
+    }
+}
--- a/src/settings/user.rs
+++ b/src/settings/user.rs
@@ -0,0 +1,86 @@
+//! 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, pep8_naming, 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,
+    pub pep8_naming: pep8_naming::settings::Settings,
+    // Non-settings exposed to the user
+    pub project_root: Option<PathBuf>,
+    pub pyproject: Option<PathBuf>,
+}
+
+impl UserConfiguration {
+    pub fn from_configuration(
+        configuration: Configuration,
+        project_root: Option<PathBuf>,
+        pyproject: Option<PathBuf>,
+    ) -> Self {
+        Self {
+            dummy_variable_rgx: configuration.dummy_variable_rgx,
+            exclude: configuration
+                .exclude
+                .into_iter()
+                .map(Exclusion::from_file_pattern)
+                .collect(),
+            extend_exclude: configuration
+                .extend_exclude
+                .into_iter()
+                .map(Exclusion::from_file_pattern)
+                .collect(),
+            extend_ignore: configuration.extend_ignore,
+            extend_select: configuration.extend_select,
+            ignore: configuration.ignore,
+            line_length: configuration.line_length,
+            per_file_ignores: configuration.per_file_ignores,
+            select: configuration.select,
+            target_version: configuration.target_version,
+            flake8_quotes: configuration.flake8_quotes,
+            pep8_naming: configuration.pep8_naming,
+            project_root,
+            pyproject,
+        }
+    }
+}
--- a/src/snapshots/rufflintertests__B013_B013.py.snap
+++ b/src/snapshots/rufflintertests__B013_B013.py.snap
@@ -0,0 +1,14 @@
+---
+source: src/linter.rs
+expression: checks
+---
+- kind:
+    RedundantTupleInExceptionHandler: ValueError
+  location:
+    row: 3
+    column: 9
+  end_location:
+    row: 3
+    column: 20
+  fix: ~
+
--- a/Show More
+++ b/Show More
Author	SHA1	Message	Date
Charlie Marsh	5a3f06bab1	Bump version to 0.0.90	2022-10-29 18:34:38 -04:00
Charlie Marsh	db59d5b558	Use a single SourceCodeLocator everywhere (#510 )	2022-10-29 18:23:24 -04:00
Charlie Marsh	2fcbf3ab62	Simplify SourceCodeLocator offset computation (#509 )	2022-10-29 18:13:42 -04:00
Anders Kaseorg	fa9b10be72	Remove leading space from C416 message (#508 )	2022-10-29 17:40:50 -04:00
Charlie Marsh	c495cef529	Move pyproject.toml logging to debug (#506 )	2022-10-29 17:07:46 -04:00
Charlie Marsh	c0c8dff6ce	Implement configuration options for pep8-naming (#505 )	2022-10-29 17:00:30 -04:00
Charlie Marsh	80b00cc89f	Add error code categories to table of contents (#504 )	2022-10-29 16:39:55 -04:00
Charlie Marsh	934db3d179	Bump version to 0.0.89	2022-10-29 15:39:17 -04:00
Charlie Marsh	6a040a0405	Update checks_gen.rs	2022-10-29 15:39:02 -04:00
Harutaka Kawamura	2821ef0f69	Implement B013 (#503 )	2022-10-29 15:36:29 -04:00
Harutaka Kawamura	343d931ddb	Ignore unittest methods and functions in N802 (#502 )	2022-10-29 15:36:09 -04:00
Harutaka Kawamura	3fc257f71b	Implement N806, 815, 816, 818 (#501 )	2022-10-29 15:35:56 -04:00
Charlie Marsh	6dbb0a17e9	Update README to reflect selection groups	2022-10-28 19:15:46 -04:00
Charlie Marsh	ae5ad6a4ac	Bump version to 0.0.88	2022-10-28 19:11:04 -04:00
Charlie Marsh	549af6c584	Regenerate CheckCodePrefix	2022-10-28 19:10:45 -04:00
Charlie Marsh	9a799eb4e6	Bump version to 0.0.87	2022-10-28 19:00:03 -04:00
Anders Kaseorg	f260b873b6	Fix “not a char boundary” error with Unicode in extract_quote (#497 )	2022-10-28 18:59:12 -04:00
Charlie Marsh	782a90b584	Add tests for resolve_codes (#498 )	2022-10-28 18:58:46 -04:00
Charlie Marsh	7df903dc4d	Move around and rename some of the Settings structs (#496 )	2022-10-28 18:46:54 -04:00
Charlie Marsh	8fc5e91ec7	Enable prefix-based check code selection (#493 )	2022-10-28 18:19:57 -04:00
Charlie Marsh	9ca1a2c273	Fix failing pyproject.toml test	2022-10-28 18:13:07 -04:00
Charlie Marsh	86265c1d7c	Implement the `flake8-quotes` plugin (#495 )	2022-10-28 17:52:11 -04:00
Charlie Marsh	a057c9a323	Move invalid_escape_sequence into pycodestyle (#494 )	2022-10-28 12:20:11 -04:00
Trevor Gross	2e63bb6dcb	Update hook id in README and in .pre-commit-config.yaml (#492 )	2022-10-27 17:32:52 -04:00
Charlie Marsh	1b5db80b32	Update pre-commit invocation in README.md	2022-10-27 17:19:22 -04:00
Charlie Marsh	3f20cea402	Bump version to 0.0.86	2022-10-27 13:09:57 -04:00
Charlie Marsh	389fe1ff64	Avoid auto-fixing unused imports in __init__.py (#489 )	2022-10-27 13:08:04 -04:00
Charlie Marsh	bad2d7ba85	Add example of per-file ignores to the README (#488 )	2022-10-27 12:58:52 -04:00
Charlie Marsh	416aa298ac	Allow whitespace in per-file ignore patterns (#487 )	2022-10-27 12:55:28 -04:00
Charlie Marsh	a535b1adbf	Replace compliance comments with check codes (#485 )	2022-10-27 09:32:18 -04:00
				`@@ -0,0 +1 @@`
				`this_should_not_be_linted = "double quote string" # noqa`
				`@@ -0,0 +1 @@`
				`this_should_not_be_linted = 'single quote string' # noqa`