Bump version to 0.0.64

CONTRIBUTING.md

@@ -14,6 +14,12 @@ your proposed change.
 ruff is written in Rust (1.63.0). You'll need to install the
 [Rust toolchain](https://www.rust-lang.org/tools/install) for development.
 
+You'll also need [Insta](https://insta.rs/docs/) to update snapshot tests:
+
+```shell
+cargo install cargo-insta
+```
+
 ### Development
 
 After cloning the repository, run ruff locally with:
@@ -58,7 +64,7 @@ similar rules are implemented.
 To add a test fixture, create a file under `resources/test/fixtures`, named to match the `CheckCode`
 you defined earlier (e.g., `E402.py`). This file should contain a variety of violations and
 non-violations designed to evaluate and demonstrate the behavior of your lint rule. Run ruff locally
-with (e.g.) `cargo run resources/test/fixtures/E402.py`. Once you're satisified with the output,
+with (e.g.) `cargo run resources/test/fixtures/E402.py`. Once you're satisfied with the output,
 codify the behavior as a snapshot test by adding a new function to the `mod tests` section of
 `src/linter.rs`, like so:
 

Cargo.lock

@@ -1907,7 +1907,7 @@ dependencies = [
 
 [[package]]
 name = "ruff"
-version = "0.0.55"
+version = "0.0.64"
 dependencies = [
  "anyhow",
  "bincode",
@@ -1926,6 +1926,7 @@ dependencies = [
  "libcst",
  "log",
  "notify",
+ "num-bigint",
  "once_cell",
  "path-absolutize",
  "rayon",
@@ -1935,6 +1936,8 @@ dependencies = [
  "rustpython-parser",
  "serde",
  "serde_json",
+ "strum",
+ "strum_macros",
  "toml",
  "update-informer",
  "walkdir",
@@ -1955,7 +1958,7 @@ dependencies = [
 [[package]]
 name = "rustpython-ast"
 version = "0.1.0"
-source = "git+https://github.com/charliermarsh/RustPython.git?rev=4f457893efc381ad5c432576b24bcc7e4a08c641#4f457893efc381ad5c432576b24bcc7e4a08c641"
+source = "git+https://github.com/charliermarsh/RustPython.git?rev=778ae2aeb521d0438d2a91bd11238bb5c2bf9d4f#778ae2aeb521d0438d2a91bd11238bb5c2bf9d4f"
 dependencies = [
  "num-bigint",
  "rustpython-common",
@@ -1965,7 +1968,7 @@ dependencies = [
 [[package]]
 name = "rustpython-common"
 version = "0.0.0"
-source = "git+https://github.com/charliermarsh/RustPython.git?rev=4f457893efc381ad5c432576b24bcc7e4a08c641#4f457893efc381ad5c432576b24bcc7e4a08c641"
+source = "git+https://github.com/charliermarsh/RustPython.git?rev=778ae2aeb521d0438d2a91bd11238bb5c2bf9d4f#778ae2aeb521d0438d2a91bd11238bb5c2bf9d4f"
 dependencies = [
  "ascii",
  "cfg-if 1.0.0",
@@ -1988,7 +1991,7 @@ dependencies = [
 [[package]]
 name = "rustpython-compiler-core"
 version = "0.1.2"
-source = "git+https://github.com/charliermarsh/RustPython.git?rev=4f457893efc381ad5c432576b24bcc7e4a08c641#4f457893efc381ad5c432576b24bcc7e4a08c641"
+source = "git+https://github.com/charliermarsh/RustPython.git?rev=778ae2aeb521d0438d2a91bd11238bb5c2bf9d4f#778ae2aeb521d0438d2a91bd11238bb5c2bf9d4f"
 dependencies = [
  "bincode",
  "bitflags",
@@ -2005,7 +2008,7 @@ dependencies = [
 [[package]]
 name = "rustpython-parser"
 version = "0.1.2"
-source = "git+https://github.com/charliermarsh/RustPython.git?rev=4f457893efc381ad5c432576b24bcc7e4a08c641#4f457893efc381ad5c432576b24bcc7e4a08c641"
+source = "git+https://github.com/charliermarsh/RustPython.git?rev=778ae2aeb521d0438d2a91bd11238bb5c2bf9d4f#778ae2aeb521d0438d2a91bd11238bb5c2bf9d4f"
 dependencies = [
  "ahash",
  "anyhow",
@@ -2252,6 +2255,28 @@ version = "0.10.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "73473c0e59e6d5812c5dfe2a064a6444949f089e20eec9a2e5506596494e4623"
 
+[[package]]
+name = "strum"
+version = "0.24.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "063e6045c0e62079840579a7e47a355ae92f60eb74daaf156fb1e84ba164e63f"
+dependencies = [
+ "strum_macros",
+]
+
+[[package]]
+name = "strum_macros"
+version = "0.24.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1e385be0d24f186b4ce2f9982191e7101bb737312ad61c1f2f984f34bcf85d59"
+dependencies = [
+ "heck",
+ "proc-macro2",
+ "quote",
+ "rustversion",
+ "syn",
+]
+
 [[package]]
 name = "syn"
 version = "1.0.101"

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ruff"
-version = "0.0.55"
+version = "0.0.64"
 edition = "2021"
 
 [lib]
@@ -27,14 +27,17 @@ once_cell = { version = "1.13.1" }
 path-absolutize = { version = "3.0.13", features = ["once_cell_cache"] }
 rayon = { version = "1.5.3" }
 regex = { version = "1.6.0" }
-rustpython-ast = { features = ["unparse"], git = "https://github.com/charliermarsh/RustPython.git", rev = "4f457893efc381ad5c432576b24bcc7e4a08c641" }
-rustpython-parser = { features = ["lalrpop"], git = "https://github.com/charliermarsh/RustPython.git", rev = "4f457893efc381ad5c432576b24bcc7e4a08c641" }
-rustpython-common = { git = "https://github.com/charliermarsh/RustPython.git", rev = "4f457893efc381ad5c432576b24bcc7e4a08c641" }
+rustpython-ast = { features = ["unparse"], git = "https://github.com/charliermarsh/RustPython.git", rev = "778ae2aeb521d0438d2a91bd11238bb5c2bf9d4f" }
+rustpython-parser = { features = ["lalrpop"], git = "https://github.com/charliermarsh/RustPython.git", rev = "778ae2aeb521d0438d2a91bd11238bb5c2bf9d4f" }
+rustpython-common = { git = "https://github.com/charliermarsh/RustPython.git", rev = "778ae2aeb521d0438d2a91bd11238bb5c2bf9d4f" }
 serde = { version = "1.0.143", features = ["derive"] }
 serde_json = { version = "1.0.83" }
 toml = { version = "0.5.9" }
 update-informer = { version = "0.5.0", default_features = false, features = ["pypi"], optional = true }
 walkdir = { version = "2.3.2" }
+strum = { version = "0.24.1", features = ["strum_macros"] }
+strum_macros = "0.24.3"
+num-bigint = "0.4.3"
 
 [dev-dependencies]
 insta = { version = "1.19.1", features = ["yaml"] }

README.md

@@ -130,6 +130,8 @@ Options:
           Enable automatic additions of noqa directives to failing lines
       --dummy-variable-rgx <DUMMY_VARIABLE_RGX>
           Regular expression matching the name of dummy variables
+      --target-version <TARGET_VERSION>
+          The minimum Python version that should be supported
   -h, --help
           Print help information
   -V, --version
@@ -213,6 +215,7 @@ ruff also implements some of the most popular Flake8 plugins natively, including
 - [`flake8-builtins`](https://pypi.org/project/flake8-builtins/)
 - [`flake8-super`](https://pypi.org/project/flake8-super/)
 - [`flake8-print`](https://pypi.org/project/flake8-print/)
+- [`flake8-comprehensions`](https://pypi.org/project/flake8-comprehensions/) (partial)
 - [`pyupgrade`](https://pypi.org/project/pyupgrade/) (partial)
 
 Beyond rule-set parity, ruff suffers from the following limitations vis-à-vis Flake8:
@@ -243,6 +246,7 @@ The 🛠 emoji indicates that a rule is automatically fixable by the `--fix` com
 | E743 | AmbiguousFunctionName | Ambiguous function name: `...` | ✅ |  |
 | E902 | IOError | IOError: `...` | ✅ |  |
 | E999 | SyntaxError | SyntaxError: `...` | ✅ |  |
+| W292 | NoNewLineAtEndOfFile | No newline at end of file | ✅ |  |
 | F401 | UnusedImport | `...` imported but unused | ✅ | 🛠 |
 | F402 | ImportShadowedByLoopVar | Import `...` from line 1 shadowed by loop variable | ✅ |  |
 | F403 | ImportStarUsed | `from ... import *` used; unable to detect undefined names | ✅ |  |
@@ -274,12 +278,25 @@ The 🛠 emoji indicates that a rule is automatically fixable by the `--fix` com
 | A001 | BuiltinVariableShadowing | Variable `...` is shadowing a python builtin |  |  |
 | A002 | BuiltinArgumentShadowing | Argument `...` is shadowing a python builtin |  |  |
 | A003 | BuiltinAttributeShadowing | Class attribute `...` is shadowing a python builtin |  |  |
+| C400 | UnnecessaryGeneratorList | Unnecessary generator - rewrite as a list comprehension |  |  |
+| C401 | UnnecessaryGeneratorSet | Unnecessary generator - rewrite as a set comprehension |  |  |
+| C402 | UnnecessaryGeneratorDict | Unnecessary generator - rewrite as a dict comprehension |  |  |
+| C403 | UnnecessaryListComprehensionSet | Unnecessary list comprehension - rewrite as a set comprehension |  |  |
+| C404 | UnnecessaryListComprehensionDict | Unnecessary list comprehension - rewrite as a dict comprehension |  |  |
+| C405 | UnnecessaryLiteralSet | Unnecessary <list/tuple> literal - rewrite as a set literal |  |  |
+| C406 | UnnecessaryLiteralDict | Unnecessary <list/tuple> literal - rewrite as a dict literal |  |  |
+| C408 | UnnecessaryCollectionCall | Unnecessary <dict/list/tuple> call - rewrite as a literal |  |  |
+| C415 | UnnecessarySubscriptReversal | Unnecessary subscript reversal of iterable within <reversed/set/sorted>() |  |  |
 | SPR001 | SuperCallWithParameters | Use `super()` instead of `super(__class__, self)` |  | 🛠 |
 | T201 | PrintFound | `print` found |  | 🛠 |
 | T203 | PPrintFound | `pprint` found |  | 🛠 |
 | U001 | UselessMetaclassType | `__metaclass__ = type` is implied |  | 🛠 |
-| R001 | UselessObjectInheritance | Class `...` inherits from object |  | 🛠 |
-| R002 | NoAssertEquals | `assertEquals` is deprecated, use `assertEqual` instead |  | 🛠 |
+| U002 | UnnecessaryAbspath | `abspath(__file__)` is unnecessary in Python 3.9 and later |  | 🛠 |
+| U003 | TypeOfPrimitive | Use `str` instead of `type(...)` |  | 🛠 |
+| U004 | UselessObjectInheritance | Class `...` inherits from object |  | 🛠 |
+| U005 | NoAssertEquals | `assertEquals` is deprecated, use `assertEqual` instead |  | 🛠 |
+| U006 | UsePEP585Annotation | Use `list` instead of `List` for type annotations |  | 🛠 |
+| U007 | UsePEP604Annotation | Use `X \| Y` for type annotations |  | 🛠 |
 | M001 | UnusedNOQA | Unused `noqa` directive |  | 🛠 |
 
 ## Integrations
@@ -307,9 +324,9 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Install Python
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@v4
         with:
           python-version: "3.10"
       - name: Install dependencies

examples/generate_rules_table.rs

@@ -1,13 +1,12 @@
 /// Generate a Markdown-compatible table of supported lint rules.
-use ruff::checks::{CheckCode, ALL_CHECK_CODES, DEFAULT_CHECK_CODES};
+use strum::IntoEnumIterator;
+
+use ruff::checks::{CheckCode, DEFAULT_CHECK_CODES};
 
 fn main() {
-    let mut check_codes: Vec<CheckCode> = ALL_CHECK_CODES.to_vec();
-    check_codes.sort();
-
     println!("| Code | Name | Message |     |     |");
     println!("| ---- | ---- | ------- | --- | --- |");
-    for check_code in check_codes {
+    for check_code in CheckCode::iter() {
         let check_kind = check_code.kind();
         let default_token = if DEFAULT_CHECK_CODES.contains(&check_code) {
             "✅"
@@ -17,9 +16,9 @@ fn main() {
         let fix_token = if check_kind.fixable() { "🛠" } else { "" };
         println!(
             "| {} | {} | {} | {} | {} |",
-            check_kind.code().as_str(),
-            check_kind.name(),
-            check_kind.body(),
+            check_kind.code().as_ref(),
+            check_kind.as_ref(),
+            check_kind.body().replace("|", r"\|"),
             default_token,
             fix_token
         );

output.py

@@ -1,37 +0,0 @@
-from collections import Counter
-
-
-def f() -> None:
-    """Docstring goes here."""
-    for x in range(5):
-        print(x)
-    else:
-        print("Nope!")
-
-
-a = {
-    "a",
-    "b",
-    "c",
-    "a",
-    "b",
-    "c",
-    "a",
-    "b",
-    "c",
-    "a",
-    "b",
-    "c",
-    "a",
-    "b",
-    "c",
-    "a",
-    "b",
-    "c",
-    "a",
-    "b",
-    "c",
-}
-
-cls(title=title, before_text=before_text, after_text=after_text, before_description=before_description, after_description=after_description, transform_type=transform_type)
-

resources/test/fixtures/C400.py

@@ -0,0 +1 @@
+x = list(x for x in range(3))

resources/test/fixtures/C401.py

@@ -0,0 +1 @@
+x = set(x for x in range(3))

resources/test/fixtures/C402.py

@@ -0,0 +1 @@
+d = dict((x, x) for x in range(3))

resources/test/fixtures/C403.py

@@ -0,0 +1 @@
+s = set([x for x in range(3)])

resources/test/fixtures/C404.py

@@ -0,0 +1 @@
+d = dict([(i, i) for i in range(3)])

resources/test/fixtures/C405.py

@@ -0,0 +1,5 @@
+s1 = set([1, 2])
+s2 = set((1, 2))
+s3 = set([])
+s4 = set(())
+s5 = set()

resources/test/fixtures/C406.py

@@ -0,0 +1,5 @@
+d1 = dict([(1, 2)])
+d2 = dict(((1, 2),))
+d3 = dict([])
+d4 = dict(())
+d5 = dict()

resources/test/fixtures/C408.py

@@ -0,0 +1,5 @@
+t = tuple()
+l = list()
+d1 = dict()
+d2 = dict(a=1)
+d3 = dict(**d2)

resources/test/fixtures/C415.py

@@ -0,0 +1,9 @@
+lst = [2, 1, 3]
+a = set(lst[::-1])
+b = reversed(lst[::-1])
+c = sorted(lst[::-1])
+d = sorted(lst[::-1], reverse=True)
+e = set(lst[2:-1])
+f = set(lst[:1:-1])
+g = set(lst[::1])
+h = set(lst[::-2])

resources/test/fixtures/F401.py

@@ -65,3 +65,24 @@ b = Union["Nut", None]
 c = cast("Vegetable", b)
 
 Field = lambda default=MISSING: field(default=default)
+
+
+# Test: access a sub-importation via an alias.
+import pyarrow as pa
+import pyarrow.csv
+
+print(pa.csv.read_csv("test.csv"))
+
+
+# Test: referencing an import via TypeAlias.
+import sys
+
+import numpy as np
+
+if sys.version_info >= (3, 10):
+    from typing import TypeAlias
+else:
+    from typing_extensions import TypeAlias
+
+
+CustomInt: TypeAlias = "np.int8 | np.int16"

resources/test/fixtures/F821.py

@@ -89,3 +89,36 @@ A = (
     f'B'
     f'{B}'
 )
+
+
+from typing import Annotated, Literal
+
+
+def arbitrary_callable() -> None:
+    ...
+
+
+class PEP593Test:
+    field: Annotated[
+        int,
+        "base64",
+        arbitrary_callable(),
+        123,
+        (1, 2, 3),
+    ]
+    field_with_stringified_type: Annotated[
+        "PEP593Test",
+        123,
+    ]
+    field_with_undefined_stringified_type: Annotated[
+        "PEP593Test123",
+        123,
+    ]
+    field_with_nested_subscript: Annotated[
+        dict[Literal["foo"], str],
+        123,
+    ]
+    field_with_undefined_nested_subscript: Annotated[
+        dict["foo", "bar"],  # Expected to fail as undefined.
+        123,
+    ]

resources/test/fixtures/U002.py

@@ -0,0 +1,15 @@
+from os.path import abspath
+
+x = abspath(__file__)
+
+
+import os
+
+
+y = os.path.abspath(__file__)
+
+
+from os import path
+
+
+z = path.abspath(__file__)

resources/test/fixtures/U003.py

@@ -0,0 +1,5 @@
+type('')
+type(b'')
+type(0)
+type(0.)
+type(0j)

resources/test/fixtures/U006.py

@@ -0,0 +1,12 @@
+from typing import List
+
+
+def f(x: List[str]) -> None:
+    ...
+
+
+import typing
+
+
+def f(x: typing.List[str]) -> None:
+    ...

resources/test/fixtures/U007.py

@@ -0,0 +1,40 @@
+from typing import Optional
+
+
+def f(x: Optional[str]) -> None:
+    ...
+
+
+import typing
+
+
+def f(x: typing.Optional[str]) -> None:
+    ...
+
+
+from typing import Union
+
+
+def f(x: Union[str, int, Union[float, bytes]]) -> None:
+    ...
+
+
+import typing
+
+
+def f(x: typing.Union[str, int]) -> None:
+    ...
+
+
+from typing import Union
+
+
+def f(x: "Union[str, int, Union[float, bytes]]") -> None:
+    ...
+
+
+import typing
+
+
+def f(x: "typing.Union[str, int]") -> None:
+    ...

resources/test/fixtures/W292_0.py

@@ -0,0 +1,2 @@
+def fn() -> None:
+    pass

resources/test/fixtures/W292_1.py

@@ -0,0 +1,2 @@
+def fn() -> None:
+    pass  # noqa: W292

resources/test/fixtures/W292_2.py

@@ -0,0 +1,2 @@
+def fn() -> None:
+    pass

src/ast.rs

@@ -1,4 +1,5 @@
 pub mod checks;
+pub mod helpers;
 pub mod operations;
 pub mod relocate;
 pub mod types;

src/ast/checks.rs

@@ -1,18 +1,18 @@
 use std::collections::BTreeSet;
 
 use itertools::izip;
+use num_bigint::BigInt;
 use regex::Regex;
 use rustpython_parser::ast::{
     Arg, ArgData, Arguments, Cmpop, Constant, Excepthandler, ExcepthandlerKind, Expr, ExprKind,
-    Keyword, Location, Stmt, StmtKind, Unaryop,
+    KeywordData, Located, Stmt, StmtKind, Unaryop,
 };
+use serde::{Deserialize, Serialize};
 
-use crate::ast::operations::SourceCodeLocator;
 use crate::ast::types::{
     Binding, BindingKind, CheckLocator, FunctionScope, Range, Scope, ScopeKind,
 };
-use crate::autofix::{fixer, fixes};
-use crate::checks::{Check, CheckKind, Fix, RejectedCmpop};
+use crate::checks::{Check, CheckKind, RejectedCmpop};
 use crate::python::builtins::BUILTINS;
 
 /// Check IfTuple compliance.
@@ -136,6 +136,86 @@ pub fn check_useless_metaclass_type(
     None
 }
 
+/// Check UnnecessaryAbspath compliance.
+pub fn check_unnecessary_abspath(func: &Expr, args: &Vec<Expr>, location: Range) -> Option<Check> {
+    // Validate the arguments.
+    if args.len() == 1 {
+        if let ExprKind::Name { id, .. } = &args[0].node {
+            if id == "__file__" {
+                match &func.node {
+                    ExprKind::Attribute { attr: id, .. } | ExprKind::Name { id, .. } => {
+                        if id == "abspath" {
+                            return Some(Check::new(CheckKind::UnnecessaryAbspath, location));
+                        }
+                    }
+                    _ => {}
+                }
+            }
+        }
+    }
+
+    None
+}
+
+#[derive(Debug, PartialEq, Eq, Serialize, Deserialize)]
+pub enum Primitive {
+    Bool,
+    Str,
+    Bytes,
+    Int,
+    Float,
+    Complex,
+}
+
+impl Primitive {
+    fn from_constant(constant: &Constant) -> Option<Self> {
+        match constant {
+            Constant::Bool(_) => Some(Primitive::Bool),
+            Constant::Str(_) => Some(Primitive::Str),
+            Constant::Bytes(_) => Some(Primitive::Bytes),
+            Constant::Int(_) => Some(Primitive::Int),
+            Constant::Float(_) => Some(Primitive::Float),
+            Constant::Complex { .. } => Some(Primitive::Complex),
+            _ => None,
+        }
+    }
+
+    pub fn builtin(&self) -> String {
+        match self {
+            Primitive::Bool => "bool".to_string(),
+            Primitive::Str => "str".to_string(),
+            Primitive::Bytes => "bytes".to_string(),
+            Primitive::Int => "int".to_string(),
+            Primitive::Float => "float".to_string(),
+            Primitive::Complex => "complex".to_string(),
+        }
+    }
+}
+
+/// Check TypeOfPrimitive compliance.
+pub fn check_type_of_primitive(func: &Expr, args: &Vec<Expr>, location: Range) -> Option<Check> {
+    // Validate the arguments.
+    if args.len() == 1 {
+        match &func.node {
+            ExprKind::Attribute { attr: id, .. } | ExprKind::Name { id, .. } => {
+                if id == "type" {
+                    if let ExprKind::Constant { value, .. } = &args[0].node {
+                        if let Some(primitive) = Primitive::from_constant(value) {
+                            return Some(Check::new(
+                                CheckKind::TypeOfPrimitive(primitive),
+                                location,
+                            ));
+                        }
+                    }
+                }
+            }
+            _ => {}
+        }
+    }
+
+    None
+}
+
 fn is_ambiguous_name(name: &str) -> bool {
     name == "l" || name == "I" || name == "O"
 }
@@ -178,13 +258,9 @@ pub fn check_ambiguous_function_name(name: &str, location: Range) -> Option<Chec
 
 /// Check UselessObjectInheritance compliance.
 pub fn check_useless_object_inheritance(
-    stmt: &Stmt,
     name: &str,
     bases: &[Expr],
-    keywords: &[Keyword],
     scope: &Scope,
-    locator: &mut SourceCodeLocator,
-    autofix: &fixer::Mode,
 ) -> Option<Check> {
     for expr in bases {
         if let ExprKind::Name { id, .. } = &expr.node {
@@ -195,22 +271,10 @@ pub fn check_useless_object_inheritance(
                         kind: BindingKind::Builtin,
                         ..
                     }) => {
-                        let mut check = Check::new(
+                        return Some(Check::new(
                             CheckKind::UselessObjectInheritance(name.to_string()),
                             Range::from_located(expr),
-                        );
-                        if matches!(autofix, fixer::Mode::Generate | fixer::Mode::Apply) {
-                            if let Some(fix) = fixes::remove_class_def_base(
-                                locator,
-                                &stmt.location,
-                                expr.location,
-                                bases,
-                                keywords,
-                            ) {
-                                check.amend(fix);
-                            }
-                        }
-                        return Some(check);
+                        ));
                     }
                     _ => {}
                 }
@@ -298,28 +362,15 @@ pub fn check_duplicate_arguments(arguments: &Arguments) -> Vec<Check> {
 }
 
 /// Check AssertEquals compliance.
-pub fn check_assert_equals(expr: &Expr, autofix: &fixer::Mode) -> Option<Check> {
+pub fn check_assert_equals(expr: &Expr) -> Option<Check> {
     if let ExprKind::Attribute { value, attr, .. } = &expr.node {
         if attr == "assertEquals" {
             if let ExprKind::Name { id, .. } = &value.node {
                 if id == "self" {
-                    let mut check =
-                        Check::new(CheckKind::NoAssertEquals, Range::from_located(expr));
-                    if matches!(autofix, fixer::Mode::Generate | fixer::Mode::Apply) {
-                        check.amend(Fix {
-                            content: "assertEqual".to_string(),
-                            location: Location::new(
-                                expr.location.row(),
-                                expr.location.column() + 1,
-                            ),
-                            end_location: Location::new(
-                                expr.location.row(),
-                                expr.location.column() + 1 + "assertEquals".len(),
-                            ),
-                            applied: false,
-                        });
-                    }
-                    return Some(check);
+                    return Some(Check::new(
+                        CheckKind::NoAssertEquals,
+                        Range::from_located(expr),
+                    ));
                 }
             }
         }
@@ -723,6 +774,256 @@ pub fn is_super_call_with_arguments(func: &Expr, args: &Vec<Expr>) -> bool {
     }
 }
 
+// flakes8-comprehensions
+/// Check `list(generator)` compliance.
+pub fn unnecessary_generator_list(expr: &Expr, func: &Expr, args: &Vec<Expr>) -> Option<Check> {
+    if args.len() == 1 {
+        if let ExprKind::Name { id, .. } = &func.node {
+            if id == "list" {
+                if let ExprKind::GeneratorExp { .. } = &args[0].node {
+                    return Some(Check::new(
+                        CheckKind::UnnecessaryGeneratorList,
+                        Range::from_located(expr),
+                    ));
+                }
+            }
+        }
+    }
+    None
+}
+
+/// Check `set(generator)` compliance.
+pub fn unnecessary_generator_set(expr: &Expr, func: &Expr, args: &Vec<Expr>) -> Option<Check> {
+    if args.len() == 1 {
+        if let ExprKind::Name { id, .. } = &func.node {
+            if id == "set" {
+                if let ExprKind::GeneratorExp { .. } = &args[0].node {
+                    return Some(Check::new(
+                        CheckKind::UnnecessaryGeneratorList,
+                        Range::from_located(expr),
+                    ));
+                }
+            }
+        }
+    }
+    None
+}
+
+/// Check `dict((x, y) for x, y in iterable)` compliance.
+pub fn unnecessary_generator_dict(expr: &Expr, func: &Expr, args: &Vec<Expr>) -> Option<Check> {
+    if args.len() == 1 {
+        if let ExprKind::Name { id, .. } = &func.node {
+            if id == "dict" {
+                if let ExprKind::GeneratorExp { elt, .. } = &args[0].node {
+                    match &elt.node {
+                        ExprKind::Tuple { elts, .. } if elts.len() == 2 => {
+                            return Some(Check::new(
+                                CheckKind::UnnecessaryListComprehensionDict,
+                                Range::from_located(expr),
+                            ));
+                        }
+                        _ => {}
+                    }
+                }
+            }
+        }
+    }
+    None
+}
+
+/// Check `set([...])` compliance.
+pub fn unnecessary_list_comprehension_set(
+    expr: &Expr,
+    func: &Expr,
+    args: &Vec<Expr>,
+) -> Option<Check> {
+    if args.len() == 1 {
+        if let ExprKind::Name { id, .. } = &func.node {
+            if id == "set" {
+                if let ExprKind::ListComp { .. } = &args[0].node {
+                    return Some(Check::new(
+                        CheckKind::UnnecessaryListComprehensionSet,
+                        Range::from_located(expr),
+                    ));
+                }
+            }
+        }
+    }
+    None
+}
+
+/// Check `dict([...])` compliance.
+pub fn unnecessary_list_comprehension_dict(
+    expr: &Expr,
+    func: &Expr,
+    args: &Vec<Expr>,
+) -> Option<Check> {
+    if args.len() == 1 {
+        if let ExprKind::Name { id, .. } = &func.node {
+            if id == "dict" {
+                if let ExprKind::ListComp { elt, .. } = &args[0].node {
+                    match &elt.node {
+                        ExprKind::Tuple { elts, .. } if elts.len() == 2 => {
+                            return Some(Check::new(
+                                CheckKind::UnnecessaryListComprehensionDict,
+                                Range::from_located(expr),
+                            ));
+                        }
+                        _ => {}
+                    }
+                }
+            }
+        }
+    }
+    None
+}
+
+/// Check `set([1, 2])` compliance.
+pub fn unnecessary_literal_set(expr: &Expr, func: &Expr, args: &Vec<Expr>) -> Option<Check> {
+    if args.len() == 1 {
+        if let ExprKind::Name { id, .. } = &func.node {
+            if id == "set" {
+                match &args[0].node {
+                    ExprKind::List { .. } => {
+                        return Some(Check::new(
+                            CheckKind::UnnecessaryLiteralSet("list".to_string()),
+                            Range::from_located(expr),
+                        ));
+                    }
+                    ExprKind::Tuple { .. } => {
+                        return Some(Check::new(
+                            CheckKind::UnnecessaryLiteralSet("tuple".to_string()),
+                            Range::from_located(expr),
+                        ));
+                    }
+                    _ => {}
+                }
+            }
+        }
+    }
+    None
+}
+
+/// Check `dict([(1, 2)])` compliance.
+pub fn unnecessary_literal_dict(expr: &Expr, func: &Expr, args: &Vec<Expr>) -> Option<Check> {
+    if args.len() == 1 {
+        if let ExprKind::Name { id, .. } = &func.node {
+            if id == "dict" {
+                match &args[0].node {
+                    ExprKind::Tuple { elts, .. } => {
+                        if let Some(elt) = elts.first() {
+                            match &elt.node {
+                                // dict((1, 2), ...))
+                                ExprKind::Tuple { elts, .. } if elts.len() == 2 => {
+                                    return Some(Check::new(
+                                        CheckKind::UnnecessaryLiteralDict("tuple".to_string()),
+                                        Range::from_located(expr),
+                                    ));
+                                }
+                                _ => {}
+                            }
+                        } else {
+                            // dict(())
+                            return Some(Check::new(
+                                CheckKind::UnnecessaryLiteralDict("tuple".to_string()),
+                                Range::from_located(expr),
+                            ));
+                        }
+                    }
+                    ExprKind::List { elts, .. } => {
+                        if let Some(elt) = elts.first() {
+                            match &elt.node {
+                                // dict([(1, 2), ...])
+                                ExprKind::Tuple { elts, .. } if elts.len() == 2 => {
+                                    return Some(Check::new(
+                                        CheckKind::UnnecessaryLiteralDict("list".to_string()),
+                                        Range::from_located(expr),
+                                    ));
+                                }
+                                _ => {}
+                            }
+                        } else {
+                            // dict([])
+                            return Some(Check::new(
+                                CheckKind::UnnecessaryLiteralDict("list".to_string()),
+                                Range::from_located(expr),
+                            ));
+                        }
+                    }
+                    _ => {}
+                }
+            }
+        }
+    }
+    None
+}
+
+pub fn unnecessary_collection_call(
+    expr: &Expr,
+    func: &Expr,
+    args: &Vec<Expr>,
+    keywords: &Vec<Located<KeywordData>>,
+) -> Option<Check> {
+    if args.is_empty() {
+        if let ExprKind::Name { id, .. } = &func.node {
+            if id == "list" || id == "tuple" {
+                // list() or tuple()
+                return Some(Check::new(
+                    CheckKind::UnnecessaryCollectionCall(id.to_string()),
+                    Range::from_located(expr),
+                ));
+            } else if id == "dict" {
+                // dict() or dict(a=1)
+                if keywords.is_empty() || keywords.iter().all(|kw| kw.node.arg.is_some()) {
+                    return Some(Check::new(
+                        CheckKind::UnnecessaryCollectionCall(id.to_string()),
+                        Range::from_located(expr),
+                    ));
+                }
+            }
+        }
+    }
+    None
+}
+
+pub fn unnecessary_subscript_reversal(expr: &Expr, func: &Expr, args: &[Expr]) -> Option<Check> {
+    if let Some(first_arg) = args.first() {
+        if let ExprKind::Name { id, .. } = &func.node {
+            if id == "set" || id == "sorted" || id == "reversed" {
+                if let ExprKind::Subscript { slice, .. } = &first_arg.node {
+                    if let ExprKind::Slice { lower, upper, step } = &slice.node {
+                        if lower.is_none() && upper.is_none() {
+                            if let Some(step) = step {
+                                if let ExprKind::UnaryOp {
+                                    op: Unaryop::USub,
+                                    operand,
+                                } = &step.node
+                                {
+                                    if let ExprKind::Constant {
+                                        value: Constant::Int(val),
+                                        ..
+                                    } = &operand.node
+                                    {
+                                        if *val == BigInt::from(1) {
+                                            return Some(Check::new(
+                                                CheckKind::UnnecessarySubscriptReversal(
+                                                    id.to_string(),
+                                                ),
+                                                Range::from_located(expr),
+                                            ));
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+    None
+}
+
 // flake8-super
 /// Check that `super()` has no args
 pub fn check_super_args(
@@ -791,11 +1092,16 @@ pub fn check_super_args(
 
 // flake8-print
 /// Check whether a function call is a `print` or `pprint` invocation
-pub fn check_print_call(expr: &Expr, func: &Expr) -> Option<Check> {
+pub fn check_print_call(
+    expr: &Expr,
+    func: &Expr,
+    check_print: bool,
+    check_pprint: bool,
+) -> Option<Check> {
     if let ExprKind::Name { id, .. } = &func.node {
-        if id == "print" {
+        if check_print && id == "print" {
             return Some(Check::new(CheckKind::PrintFound, Range::from_located(expr)));
-        } else if id == "pprint" {
+        } else if check_pprint && id == "pprint" {
             return Some(Check::new(
                 CheckKind::PPrintFound,
                 Range::from_located(expr),
@@ -805,7 +1111,7 @@ pub fn check_print_call(expr: &Expr, func: &Expr) -> Option<Check> {
 
     if let ExprKind::Attribute { value, attr, .. } = &func.node {
         if let ExprKind::Name { id, .. } = &value.node {
-            if id == "pprint" && attr == "pprint" {
+            if check_pprint && id == "pprint" && attr == "pprint" {
                 return Some(Check::new(
                     CheckKind::PPrintFound,
                     Range::from_located(expr),

src/ast/helpers.rs

@@ -0,0 +1,74 @@
+use once_cell::sync::Lazy;
+use regex::Regex;
+use rustpython_ast::{Expr, ExprKind, StmtKind};
+
+use crate::python::typing;
+
+static DUNDER_REGEX: Lazy<Regex> = Lazy::new(|| Regex::new(r"__[^\s]+__").unwrap());
+
+pub enum SubscriptKind {
+    AnnotatedSubscript,
+    PEP593AnnotatedSubscript,
+}
+
+pub fn match_annotated_subscript(expr: &Expr) -> Option<SubscriptKind> {
+    match &expr.node {
+        ExprKind::Attribute { attr, .. } => {
+            if typing::is_annotated_subscript(attr) {
+                Some(SubscriptKind::AnnotatedSubscript)
+            } else if typing::is_pep593_annotated_subscript(attr) {
+                Some(SubscriptKind::PEP593AnnotatedSubscript)
+            } else {
+                None
+            }
+        }
+        ExprKind::Name { id, .. } => {
+            if typing::is_annotated_subscript(id) {
+                Some(SubscriptKind::AnnotatedSubscript)
+            } else if typing::is_pep593_annotated_subscript(id) {
+                Some(SubscriptKind::PEP593AnnotatedSubscript)
+            } else {
+                None
+            }
+        }
+        _ => None,
+    }
+}
+
+pub fn is_assignment_to_a_dunder(node: &StmtKind) -> bool {
+    // Check whether it's an assignment to a dunder, with or without a type annotation.
+    // This is what pycodestyle (as of 2.9.1) does.
+    match node {
+        StmtKind::Assign {
+            targets,
+            value: _,
+            type_comment: _,
+        } => {
+            if targets.len() != 1 {
+                return false;
+            }
+            match &targets[0].node {
+                ExprKind::Name { id, ctx: _ } => DUNDER_REGEX.is_match(id),
+                _ => false,
+            }
+        }
+        StmtKind::AnnAssign {
+            target,
+            annotation: _,
+            value: _,
+            simple: _,
+        } => match &target.node {
+            ExprKind::Name { id, ctx: _ } => DUNDER_REGEX.is_match(id),
+            _ => false,
+        },
+        _ => false,
+    }
+}
+
+pub fn match_name_or_attr(expr: &Expr, target: &str) -> bool {
+    match &expr.node {
+        ExprKind::Attribute { attr, .. } => target == attr,
+        ExprKind::Name { id, .. } => target == id,
+        _ => false,
+    }
+}

src/ast/types.rs

@@ -74,9 +74,9 @@ pub enum BindingKind {
     Export(Vec<String>),
     FutureImportation,
     StarImportation,
-    Importation(String, BindingContext),
-    FromImportation(String, BindingContext),
-    SubmoduleImportation(String, BindingContext),
+    Importation(String, String, BindingContext),
+    FromImportation(String, String, BindingContext),
+    SubmoduleImportation(String, String, BindingContext),
 }
 
 #[derive(Clone, Debug)]

src/ast/visitor.rs

@@ -1,3 +1,4 @@
+use crate::ast::helpers::match_name_or_attr;
 use rustpython_parser::ast::{
     Alias, Arg, Arguments, Boolop, Cmpop, Comprehension, Constant, Excepthandler,
     ExcepthandlerKind, Expr, ExprContext, ExprKind, Keyword, MatchCase, Operator, Pattern,
@@ -148,7 +149,11 @@ pub fn walk_stmt<'a, V: Visitor<'a> + ?Sized>(visitor: &mut V, stmt: &'a Stmt) {
         } => {
             visitor.visit_annotation(annotation);
             if let Some(expr) = value {
-                visitor.visit_expr(expr);
+                if match_name_or_attr(annotation, "TypeAlias") {
+                    visitor.visit_annotation(expr);
+                } else {
+                    visitor.visit_expr(expr);
+                }
             }
             visitor.visit_expr(target);
         }

src/check_ast.rs

@@ -3,14 +3,14 @@ use std::ops::Deref;
 use std::path::Path;
 
 use log::error;
-use once_cell::sync::Lazy;
-use regex::Regex;
+use rustpython_ast::Location;
 use rustpython_parser::ast::{
     Arg, Arguments, Constant, Excepthandler, ExcepthandlerKind, Expr, ExprContext, ExprKind,
     KeywordData, Operator, Stmt, StmtKind, Suite,
 };
 use rustpython_parser::parser;
 
+use crate::ast::helpers::{match_name_or_attr, SubscriptKind};
 use crate::ast::operations::{extract_all_names, SourceCodeLocator};
 use crate::ast::relocate::relocate_expr;
 use crate::ast::types::{
@@ -18,30 +18,32 @@ use crate::ast::types::{
     ScopeKind,
 };
 use crate::ast::visitor::{walk_excepthandler, Visitor};
-use crate::ast::{checks, operations, visitor};
+use crate::ast::{checks, helpers, operations, visitor};
 use crate::autofix::{fixer, fixes};
 use crate::checks::{Check, CheckCode, CheckKind};
+use crate::plugins;
 use crate::python::builtins::{BUILTINS, MAGIC_GLOBALS};
 use crate::python::future::ALL_FEATURE_NAMES;
-use crate::python::typing;
-use crate::settings::Settings;
+use crate::settings::{PythonVersion, Settings};
 
 pub const GLOBAL_SCOPE_INDEX: usize = 0;
 
-static DUNDER_REGEX: Lazy<Regex> = Lazy::new(|| Regex::new(r"__[^\s]+__").unwrap());
-
-struct Checker<'a> {
+pub struct Checker<'a> {
     // Input data.
-    locator: SourceCodeLocator<'a>,
-    settings: &'a Settings,
-    autofix: &'a fixer::Mode,
     path: &'a Path,
+    // TODO(charlie): Separate immutable from mutable state. (None of these should ever change.)
+    pub(crate) locator: SourceCodeLocator<'a>,
+    pub(crate) settings: &'a Settings,
+    pub(crate) autofix: &'a fixer::Mode,
     // Computed checks.
     checks: Vec<Check>,
+    // Edit tracking.
+    // TODO(charlie): Instead of exposing deletions, wrap in a public API.
+    pub(crate) deletions: BTreeSet<usize>,
     // Retain all scopes and parent nodes, along with a stack of indexes to track which are active
     // at various points in time.
-    parents: Vec<&'a Stmt>,
-    parent_stack: Vec<usize>,
+    pub(crate) parents: Vec<&'a Stmt>,
+    pub(crate) parent_stack: Vec<usize>,
     scopes: Vec<Scope>,
     scope_stack: Vec<usize>,
     dead_scopes: Vec<usize>,
@@ -50,7 +52,7 @@ struct Checker<'a> {
     deferred_functions: Vec<(&'a Stmt, Vec<usize>, Vec<usize>)>,
     deferred_lambdas: Vec<(&'a Expr, Vec<usize>, Vec<usize>)>,
     deferred_assignments: Vec<usize>,
-    // Derivative state.
+    // Internal, derivative state.
     in_f_string: Option<Range>,
     in_annotation: bool,
     in_literal: bool,
@@ -58,8 +60,6 @@ struct Checker<'a> {
     seen_docstring: bool,
     futures_allowed: bool,
     annotations_future_enabled: bool,
-    // Edit tracking.
-    deletions: BTreeSet<usize>,
 }
 
 impl<'a> Checker<'a> {
@@ -97,52 +97,6 @@ impl<'a> Checker<'a> {
     }
 }
 
-fn match_name_or_attr(expr: &Expr, target: &str) -> bool {
-    match &expr.node {
-        ExprKind::Attribute { attr, .. } => target == attr,
-        ExprKind::Name { id, .. } => target == id,
-        _ => false,
-    }
-}
-
-fn is_annotated_subscript(expr: &Expr) -> bool {
-    match &expr.node {
-        ExprKind::Attribute { attr, .. } => typing::is_annotated_subscript(attr),
-        ExprKind::Name { id, .. } => typing::is_annotated_subscript(id),
-        _ => false,
-    }
-}
-
-fn is_assignment_to_a_dunder(node: &StmtKind) -> bool {
-    // Check whether it's an assignment to a dunder, with or without a type annotation.
-    // This is what pycodestyle (as of 2.9.1) does.
-    match node {
-        StmtKind::Assign {
-            targets,
-            value: _,
-            type_comment: _,
-        } => {
-            if targets.len() != 1 {
-                return false;
-            }
-            match &targets[0].node {
-                ExprKind::Name { id, ctx: _ } => DUNDER_REGEX.is_match(id),
-                _ => false,
-            }
-        }
-        StmtKind::AnnAssign {
-            target,
-            annotation: _,
-            value: _,
-            simple: _,
-        } => match &target.node {
-            ExprKind::Name { id, ctx: _ } => DUNDER_REGEX.is_match(id),
-            _ => false,
-        },
-        _ => false,
-    }
-}
-
 impl<'a, 'b> Visitor<'b> for Checker<'a>
 where
     'b: 'a,
@@ -203,7 +157,7 @@ where
                 self.futures_allowed = false;
 
                 if !self.seen_non_import
-                    && !is_assignment_to_a_dunder(node)
+                    && !helpers::is_assignment_to_a_dunder(node)
                     && !operations::in_nested_block(&self.parent_stack, &self.parents)
                 {
                     self.seen_non_import = true;
@@ -216,8 +170,7 @@ where
             StmtKind::Global { names } | StmtKind::Nonlocal { names } => {
                 let global_scope_id = self.scopes[GLOBAL_SCOPE_INDEX].id;
 
-                let current_scope =
-                    &self.scopes[*(self.scope_stack.last().expect("No current scope found."))];
+                let current_scope = self.current_scope();
                 let current_scope_id = current_scope.id;
                 if current_scope_id != global_scope_id {
                     for name in names {
@@ -365,20 +318,8 @@ where
                 decorator_list,
                 ..
             } => {
-                if self.settings.enabled.contains(&CheckCode::R001) {
-                    let scope =
-                        &self.scopes[*(self.scope_stack.last().expect("No current scope found."))];
-                    if let Some(check) = checks::check_useless_object_inheritance(
-                        stmt,
-                        name,
-                        bases,
-                        keywords,
-                        scope,
-                        &mut self.locator,
-                        self.autofix,
-                    ) {
-                        self.checks.push(check);
-                    }
+                if self.settings.enabled.contains(&CheckCode::U004) {
+                    plugins::useless_object_inheritance(self, stmt, name, bases, keywords);
                 }
 
                 if self.settings.enabled.contains(&CheckCode::E742) {
@@ -423,13 +364,16 @@ where
 
                 for alias in names {
                     if alias.node.name.contains('.') && alias.node.asname.is_none() {
-                        // TODO(charlie): Multiple submodule imports with the same parent module
-                        // will be merged into a single binding.
+                        // Given `import foo.bar`, `name` would be "foo", and `full_name` would be
+                        // "foo.bar".
+                        let name = alias.node.name.split('.').next().unwrap();
+                        let full_name = &alias.node.name;
                         self.add_binding(
-                            alias.node.name.split('.').next().unwrap().to_string(),
+                            name.to_string(),
                             Binding {
                                 kind: BindingKind::SubmoduleImportation(
-                                    alias.node.name.to_string(),
+                                    name.to_string(),
+                                    full_name.to_string(),
                                     self.binding_context(),
                                 ),
                                 used: None,
@@ -441,19 +385,17 @@ where
                             self.check_builtin_shadowing(asname, Range::from_located(stmt), false);
                         }
 
+                        // Given `import foo`, `name` and `full_name` would both be `foo`.
+                        // Given `import foo as bar`, `name` would be `bar` and `full_name` would
+                        // be `foo`.
+                        let name = alias.node.asname.as_ref().unwrap_or(&alias.node.name);
+                        let full_name = &alias.node.name;
                         self.add_binding(
-                            alias
-                                .node
-                                .asname
-                                .clone()
-                                .unwrap_or_else(|| alias.node.name.clone()),
+                            name.to_string(),
                             Binding {
                                 kind: BindingKind::Importation(
-                                    alias
-                                        .node
-                                        .asname
-                                        .clone()
-                                        .unwrap_or_else(|| alias.node.name.clone()),
+                                    name.to_string(),
+                                    full_name.to_string(),
                                     self.binding_context(),
                                 ),
                                 used: None,
@@ -482,14 +424,10 @@ where
                 }
 
                 for alias in names {
-                    let name = alias
-                        .node
-                        .asname
-                        .clone()
-                        .unwrap_or_else(|| alias.node.name.clone());
                     if let Some("__future__") = module.as_deref() {
+                        let name = alias.node.asname.as_ref().unwrap_or(&alias.node.name);
                         self.add_binding(
-                            name,
+                            name.to_string(),
                             Binding {
                                 kind: BindingKind::FutureImportation,
                                 used: Some((
@@ -568,18 +506,26 @@ where
                             self.check_builtin_shadowing(asname, Range::from_located(stmt), false);
                         }
 
-                        let binding = Binding {
-                            kind: BindingKind::FromImportation(
-                                match module {
-                                    None => name.clone(),
-                                    Some(parent) => format!("{}.{}", parent, name),
-                                },
-                                self.binding_context(),
-                            ),
-                            used: None,
-                            range: Range::from_located(stmt),
+                        // Given `from foo import bar`, `name` would be "bar" and `full_name` would
+                        // be "foo.bar". Given `from foo import bar as baz`, `name` would be "baz"
+                        // and `full_name` would be "foo.bar".
+                        let name = alias.node.asname.as_ref().unwrap_or(&alias.node.name);
+                        let full_name = match module {
+                            None => alias.node.name.to_string(),
+                            Some(parent) => format!("{}.{}", parent, alias.node.name),
                         };
-                        self.add_binding(name, binding)
+                        self.add_binding(
+                            name.to_string(),
+                            Binding {
+                                kind: BindingKind::FromImportation(
+                                    name.to_string(),
+                                    full_name,
+                                    self.binding_context(),
+                                ),
+                                used: None,
+                                range: Range::from_located(stmt),
+                            },
+                        )
                     }
                 }
             }
@@ -597,25 +543,12 @@ where
             }
             StmtKind::If { test, .. } => {
                 if self.settings.enabled.contains(&CheckCode::F634) {
-                    if let Some(check) =
-                        checks::check_if_tuple(test, self.locate_check(Range::from_located(stmt)))
-                    {
-                        self.checks.push(check);
-                    }
+                    plugins::if_tuple(self, stmt, test);
                 }
             }
             StmtKind::Assert { test, .. } => {
-                if self
-                    .settings
-                    .enabled
-                    .contains(CheckKind::AssertTuple.code())
-                {
-                    if let Some(check) = checks::check_assert_tuple(
-                        test,
-                        self.locate_check(Range::from_located(stmt)),
-                    ) {
-                        self.checks.push(check);
-                    }
+                if self.settings.enabled.contains(&CheckCode::F631) {
+                    plugins::assert_tuple(self, stmt, test);
                 }
             }
             StmtKind::Try { handlers, .. } => {
@@ -635,35 +568,7 @@ where
                     }
                 }
                 if self.settings.enabled.contains(&CheckCode::U001) {
-                    if let Some(mut check) = checks::check_useless_metaclass_type(
-                        targets,
-                        value,
-                        self.locate_check(Range::from_located(stmt)),
-                    ) {
-                        if matches!(self.autofix, fixer::Mode::Generate | fixer::Mode::Apply) {
-                            let context = self.binding_context();
-                            let deleted: Vec<&Stmt> = self
-                                .deletions
-                                .iter()
-                                .map(|index| self.parents[*index])
-                                .collect();
-
-                            match fixes::remove_stmt(
-                                self.parents[context.defined_by],
-                                context.defined_in.map(|index| self.parents[index]),
-                                &deleted,
-                            ) {
-                                Ok(fix) => {
-                                    if fix.content.is_empty() || fix.content == "pass" {
-                                        self.deletions.insert(context.defined_by);
-                                    }
-                                    check.amend(fix)
-                                }
-                                Err(e) => error!("Failed to fix unused imports: {}", e),
-                            }
-                        }
-                        self.checks.push(check);
-                    }
+                    plugins::useless_metaclass_type(self, stmt, value, targets);
                 }
             }
             StmtKind::AnnAssign { value, .. } => {
@@ -739,7 +644,14 @@ where
 
         // Pre-visit.
         match &expr.node {
-            ExprKind::Subscript { value, .. } => {
+            ExprKind::Subscript { value, slice, .. } => {
+                // Ex) typing.List[...]
+                if self.settings.enabled.contains(&CheckCode::U007)
+                    && self.settings.target_version >= PythonVersion::Py39
+                {
+                    plugins::use_pep604_annotation(self, expr, value, slice);
+                }
+
                 if match_name_or_attr(value, "Literal") {
                     self.in_literal = true;
                 }
@@ -761,7 +673,16 @@ where
                 }
             }
             ExprKind::Name { id, ctx } => match ctx {
-                ExprContext::Load => self.handle_node_load(expr),
+                ExprContext::Load => {
+                    // Ex) List[...]
+                    if self.settings.enabled.contains(&CheckCode::U006)
+                        && self.settings.target_version >= PythonVersion::Py39
+                    {
+                        plugins::use_pep585_annotation(self, expr, id);
+                    }
+
+                    self.handle_node_load(expr);
+                }
                 ExprContext::Store => {
                     if self.settings.enabled.contains(&CheckCode::E741) {
                         if let Some(check) = checks::check_ambiguous_variable_name(
@@ -774,81 +695,114 @@ where
 
                     self.check_builtin_shadowing(id, Range::from_located(expr), true);
 
-                    let parent =
-                        self.parents[*(self.parent_stack.last().expect("No parent found."))];
-                    self.handle_node_store(expr, parent);
+                    self.handle_node_store(expr, self.current_parent());
                 }
                 ExprContext::Del => self.handle_node_delete(expr),
             },
-            ExprKind::Call { func, args, .. } => {
-                if self.settings.enabled.contains(&CheckCode::R002) {
-                    if let Some(check) = checks::check_assert_equals(func, self.autofix) {
-                        self.checks.push(check)
+            ExprKind::Attribute { value, attr, .. } => {
+                // Ex) typing.List[...]
+                if self.settings.enabled.contains(&CheckCode::U006)
+                    && self.settings.target_version >= PythonVersion::Py39
+                {
+                    if let ExprKind::Name { id, .. } = &value.node {
+                        if id == "typing" {
+                            plugins::use_pep585_annotation(self, expr, attr);
+                        }
                     }
                 }
+            }
+            ExprKind::Call {
+                func,
+                args,
+                keywords,
+                ..
+            } => {
+                if self.settings.enabled.contains(&CheckCode::U005) {
+                    plugins::assert_equals(self, func);
+                }
 
                 // flake8-super
                 if self.settings.enabled.contains(&CheckCode::SPR001) {
-                    // Only bother going through the super check at all if we're in a `super` call.
-                    // (We check this in `check_super_args` too, so this is just an optimization.)
-                    if checks::is_super_call_with_arguments(func, args) {
-                        let scope = &mut self.scopes
-                            [*(self.scope_stack.last().expect("No current scope found."))];
-                        let parents: Vec<&Stmt> = self
-                            .parent_stack
-                            .iter()
-                            .map(|index| self.parents[*index])
-                            .collect();
-                        if let Some(mut check) =
-                            checks::check_super_args(scope, &parents, expr, func, args)
-                        {
-                            if matches!(self.autofix, fixer::Mode::Generate | fixer::Mode::Apply) {
-                                if let Some(fix) =
-                                    fixes::remove_super_arguments(&mut self.locator, expr)
-                                {
-                                    check.amend(fix);
-                                }
-                            }
-                            self.checks.push(check)
-                        }
-                    }
+                    plugins::super_call_with_parameters(self, expr, func, args);
                 }
 
                 // flake8-print
                 if self.settings.enabled.contains(&CheckCode::T201)
                     || self.settings.enabled.contains(&CheckCode::T203)
                 {
-                    if let Some(mut check) = checks::check_print_call(expr, func) {
-                        if matches!(self.autofix, fixer::Mode::Generate | fixer::Mode::Apply) {
-                            let context = self.binding_context();
-                            if matches!(
-                                self.parents[context.defined_by].node,
-                                StmtKind::Expr { .. }
-                            ) {
-                                let deleted: Vec<&Stmt> = self
-                                    .deletions
-                                    .iter()
-                                    .map(|index| self.parents[*index])
-                                    .collect();
+                    plugins::print_call(self, expr, func);
+                }
 
-                                match fixes::remove_stmt(
-                                    self.parents[context.defined_by],
-                                    context.defined_in.map(|index| self.parents[index]),
-                                    &deleted,
-                                ) {
-                                    Ok(fix) => {
-                                        if fix.content.is_empty() || fix.content == "pass" {
-                                            self.deletions.insert(context.defined_by);
-                                        }
-                                        check.amend(fix)
-                                    }
-                                    Err(e) => error!("Failed to fix unused imports: {}", e),
-                                }
-                            }
-                        }
+                // flake8-comprehensions
+                if self.settings.enabled.contains(&CheckCode::C400) {
+                    if let Some(check) = checks::unnecessary_generator_list(expr, func, args) {
+                        self.checks.push(check);
+                    };
+                }
 
-                        self.checks.push(check)
-                    }
+                if self.settings.enabled.contains(&CheckCode::C401) {
+                    if let Some(check) = checks::unnecessary_generator_set(expr, func, args) {
+                        self.checks.push(check);
+                    };
+                }
+
+                if self.settings.enabled.contains(&CheckCode::C402) {
+                    if let Some(check) = checks::unnecessary_generator_dict(expr, func, args) {
+                        self.checks.push(check);
+                    };
+                }
+
+                if self.settings.enabled.contains(&CheckCode::C403) {
+                    if let Some(check) =
+                        checks::unnecessary_list_comprehension_set(expr, func, args)
+                    {
+                        self.checks.push(check);
+                    };
+                }
+
+                if self.settings.enabled.contains(&CheckCode::C404) {
+                    if let Some(check) =
+                        checks::unnecessary_list_comprehension_dict(expr, func, args)
+                    {
+                        self.checks.push(check);
+                    };
+                }
+
+                if self.settings.enabled.contains(&CheckCode::C405) {
+                    if let Some(check) = checks::unnecessary_literal_set(expr, func, args) {
+                        self.checks.push(check);
+                    };
+                }
+
+                if self.settings.enabled.contains(&CheckCode::C406) {
+                    if let Some(check) = checks::unnecessary_literal_dict(expr, func, args) {
+                        self.checks.push(check);
+                    };
+                }
+
+                if self.settings.enabled.contains(&CheckCode::C408) {
+                    if let Some(check) =
+                        checks::unnecessary_collection_call(expr, func, args, keywords)
+                    {
+                        self.checks.push(check);
+                    };
+                }
+
+                if self.settings.enabled.contains(&CheckCode::C415) {
+                    if let Some(check) = checks::unnecessary_subscript_reversal(expr, func, args) {
+                        self.checks.push(check);
+                    };
+                }
+
+                // pyupgrade
+                if self.settings.enabled.contains(&CheckCode::U002)
+                    && self.settings.target_version >= PythonVersion::Py310
+                {
+                    plugins::unnecessary_abspath(self, expr, func, args);
+                }
+
+                if self.settings.enabled.contains(&CheckCode::U003) {
+                    plugins::type_of_primitive(self, expr, func, args);
                 }
 
                 if let ExprKind::Name { id, ctx } = &func.node {
@@ -879,8 +833,7 @@ where
                 }
             }
             ExprKind::Yield { .. } | ExprKind::YieldFrom { .. } | ExprKind::Await { .. } => {
-                let scope =
-                    &self.scopes[*(self.scope_stack.last().expect("No current scope found."))];
+                let scope = self.current_scope();
                 if self
                     .settings
                     .enabled
@@ -916,22 +869,7 @@ where
                 ..
             } => {
                 if self.settings.enabled.contains(&CheckCode::F633) {
-                    if let ExprKind::Name { id, .. } = &left.node {
-                        if id == "print" {
-                            let scope = &self.scopes
-                                [*(self.scope_stack.last().expect("No current scope found."))];
-                            if let Some(Binding {
-                                kind: BindingKind::Builtin,
-                                ..
-                            }) = scope.values.get("print")
-                            {
-                                self.checks.push(Check::new(
-                                    CheckKind::InvalidPrintSyntax,
-                                    Range::from_located(left),
-                                ));
-                            }
-                        }
-                    }
+                    plugins::invalid_print_syntax(self, left);
                 }
             }
             ExprKind::UnaryOp { op, operand } => {
@@ -985,9 +923,11 @@ where
             ExprKind::Constant {
                 value: Constant::Str(value),
                 ..
-            } if self.in_annotation && !self.in_literal => {
-                self.deferred_string_annotations
-                    .push((Range::from_located(expr), value));
+            } => {
+                if self.in_annotation && !self.in_literal {
+                    self.deferred_string_annotations
+                        .push((Range::from_located(expr), value));
+                }
             }
             ExprKind::Lambda { args, .. } => {
                 // Visit the arguments, but avoid the body, which will be deferred.
@@ -1138,12 +1078,35 @@ where
                 }
             }
             ExprKind::Subscript { value, slice, ctx } => {
-                if is_annotated_subscript(value) {
-                    self.visit_expr(value);
-                    self.visit_annotation(slice);
-                    self.visit_expr_context(ctx);
-                } else {
-                    visitor::walk_expr(self, expr);
+                match helpers::match_annotated_subscript(value) {
+                    Some(subscript) => match subscript {
+                        // Ex) Optional[int]
+                        SubscriptKind::AnnotatedSubscript => {
+                            self.visit_expr(value);
+                            self.visit_annotation(slice);
+                            self.visit_expr_context(ctx);
+                        }
+                        // Ex) Annotated[int, "Hello, world!"]
+                        SubscriptKind::PEP593AnnotatedSubscript => {
+                            // First argument is a type (including forward references); the rest are
+                            // arbitrary Python objects.
+                            self.visit_expr(value);
+                            if let ExprKind::Tuple { elts, ctx } = &slice.node {
+                                if let Some(expr) = elts.first() {
+                                    self.visit_expr(expr);
+                                    self.in_annotation = false;
+                                    for expr in elts.iter().skip(1) {
+                                        self.visit_expr(expr);
+                                    }
+                                    self.in_annotation = true;
+                                    self.visit_expr_context(ctx);
+                                }
+                            } else {
+                                error!("Found non-ExprKind::Tuple argument to PEP 593 Annotation.")
+                            }
+                        }
+                    },
+                    None => visitor::walk_expr(self, expr),
                 }
             }
             _ => visitor::walk_expr(self, expr),
@@ -1191,11 +1154,7 @@ where
                             false,
                         );
 
-                        let scope = &self.scopes
-                            [*(self.scope_stack.last().expect("No current scope found."))];
-                        if scope.values.contains_key(name) {
-                            let parent = self.parents
-                                [*(self.parent_stack.last().expect("No parent found."))];
+                        if self.current_scope().values.contains_key(name) {
                             self.handle_node_store(
                                 &Expr::new(
                                     excepthandler.location,
@@ -1205,15 +1164,11 @@ where
                                         ctx: ExprContext::Store,
                                     },
                                 ),
-                                parent,
+                                self.current_parent(),
                             );
                         }
 
-                        let parent =
-                            self.parents[*(self.parent_stack.last().expect("No parent found."))];
-                        let scope = &self.scopes
-                            [*(self.scope_stack.last().expect("No current scope found."))];
-                        let definition = scope.values.get(name).cloned();
+                        let definition = self.current_scope().values.get(name).cloned();
                         self.handle_node_store(
                             &Expr::new(
                                 excepthandler.location,
@@ -1223,7 +1178,7 @@ where
                                     ctx: ExprContext::Store,
                                 },
                             ),
-                            parent,
+                            self.current_parent(),
                         );
 
                         walk_excepthandler(self, excepthandler);
@@ -1305,7 +1260,52 @@ impl CheckLocator for Checker<'_> {
     }
 }
 
+fn try_mark_used(scope: &mut Scope, scope_id: usize, id: &str, expr: &Expr) -> bool {
+    let alias = if let Some(binding) = scope.values.get_mut(id) {
+        // Mark the binding as used.
+        binding.used = Some((scope_id, Range::from_located(expr)));
+
+        // If the name of the sub-importation is the same as an alias of another importation and the
+        // alias is used, that sub-importation should be marked as used too.
+        //
+        // This handles code like:
+        //   import pyarrow as pa
+        //   import pyarrow.csv
+        //   print(pa.csv.read_csv("test.csv"))
+        if let BindingKind::Importation(name, full_name, _)
+        | BindingKind::FromImportation(name, full_name, _)
+        | BindingKind::SubmoduleImportation(name, full_name, _) = &binding.kind
+        {
+            let has_alias = full_name
+                .split('.')
+                .last()
+                .map(|segment| segment != name)
+                .unwrap_or_default();
+            if has_alias {
+                // Clone the alias. (We'll mutate it below.)
+                full_name.to_string()
+            } else {
+                return true;
+            }
+        } else {
+            return true;
+        }
+    } else {
+        return false;
+    };
+
+    // Mark the sub-importation as used.
+    if let Some(binding) = scope.values.get_mut(&alias) {
+        binding.used = Some((scope_id, Range::from_located(expr)));
+    }
+    true
+}
+
 impl<'a> Checker<'a> {
+    pub fn add_check(&mut self, check: Check) {
+        self.checks.push(check);
+    }
+
     fn push_parent(&mut self, parent: &'a Stmt) {
         self.parent_stack.push(self.parents.len());
         self.parents.push(parent);
@@ -1355,7 +1355,15 @@ impl<'a> Checker<'a> {
         }
     }
 
-    fn binding_context(&self) -> BindingContext {
+    pub fn current_scope(&self) -> &Scope {
+        &self.scopes[*(self.scope_stack.last().expect("No current scope found."))]
+    }
+
+    pub fn current_parent(&self) -> &'a Stmt {
+        self.parents[*(self.parent_stack.last().expect("No parent found."))]
+    }
+
+    pub fn binding_context(&self) -> BindingContext {
         let mut rev = self.parent_stack.iter().rev().fuse();
         let defined_by = *rev.next().expect("Expected to bind within a statement.");
         let defined_in = rev.next().cloned();
@@ -1376,7 +1384,11 @@ impl<'a> Checker<'a> {
                     && matches!(binding.kind, BindingKind::LoopVar)
                     && matches!(
                         existing.kind,
-                        BindingKind::Importation(_, _) | BindingKind::FromImportation(_, _)
+                        BindingKind::Importation(_, _, _)
+                            | BindingKind::FromImportation(_, _, _)
+                            | BindingKind::SubmoduleImportation(_, _, _)
+                            | BindingKind::StarImportation
+                            | BindingKind::FutureImportation
                     )
                 {
                     self.checks.push(Check::new(
@@ -1415,8 +1427,8 @@ impl<'a> Checker<'a> {
                         continue;
                     }
                 }
-                if let Some(binding) = scope.values.get_mut(id) {
-                    binding.used = Some((scope_id, Range::from_located(expr)));
+
+                if try_mark_used(scope, scope_id, id, expr) {
                     return;
                 }
 
@@ -1586,14 +1598,37 @@ impl<'a> Checker<'a> {
     where
         'b: 'a,
     {
-        while let Some((location, expression)) = self.deferred_string_annotations.pop() {
+        while let Some((range, expression)) = self.deferred_string_annotations.pop() {
+            // HACK(charlie): We need to modify `range` such that it represents the range of the
+            // expression _within_ the string annotation (as opposed to the range of the string
+            // annotation itself). RustPython seems to return an off-by-one start column for every
+            // string value, so we check for double quotes (which are really triple quotes).
+            let contents = self.locator.slice_source_code_at(&range.location);
+            let range = if contents.starts_with("\"\"") || contents.starts_with("\'\'") {
+                Range {
+                    location: Location::new(range.location.row(), range.location.column() + 2),
+                    end_location: Location::new(
+                        range.end_location.row(),
+                        range.end_location.column() - 2,
+                    ),
+                }
+            } else {
+                Range {
+                    location: Location::new(range.location.row(), range.location.column()),
+                    end_location: Location::new(
+                        range.end_location.row(),
+                        range.end_location.column() - 1,
+                    ),
+                }
+            };
+
             if let Ok(mut expr) = parser::parse_expression(expression, "<filename>") {
-                relocate_expr(&mut expr, location);
+                relocate_expr(&mut expr, range);
                 allocator.push(expr);
             } else if self.settings.enabled.contains(&CheckCode::F722) {
                 self.checks.push(Check::new(
                     CheckKind::ForwardAnnotationSyntaxError(expression.to_string()),
-                    self.locate_check(location),
+                    self.locate_check(range),
                 ));
             }
         }
@@ -1728,25 +1763,25 @@ impl<'a> Checker<'a> {
 
                     if !used {
                         match &binding.kind {
-                            BindingKind::FromImportation(full_name, context) => {
+                            BindingKind::FromImportation(_, full_name, context) => {
                                 let full_names = unused
                                     .entry((
                                         ImportKind::ImportFrom,
                                         context.defined_by,
                                         context.defined_in,
                                     ))
-                                    .or_insert(vec![]);
+                                    .or_default();
                                 full_names.push(full_name);
                             }
-                            BindingKind::Importation(full_name, context)
-                            | BindingKind::SubmoduleImportation(full_name, context) => {
+                            BindingKind::Importation(_, full_name, context)
+                            | BindingKind::SubmoduleImportation(_, full_name, context) => {
                                 let full_names = unused
                                     .entry((
                                         ImportKind::Import,
                                         context.defined_by,
                                         context.defined_in,
                                     ))
-                                    .or_insert(vec![]);
+                                    .or_default();
                                 full_names.push(full_name);
                             }
                             _ => {}
@@ -1758,12 +1793,8 @@ impl<'a> Checker<'a> {
                     let child = self.parents[defined_by];
                     let parent = defined_in.map(|defined_in| self.parents[defined_in]);
 
-                    let mut check = Check::new(
-                        CheckKind::UnusedImport(full_names.join(", ")),
-                        self.locate_check(Range::from_located(child)),
-                    );
-
-                    if matches!(self.autofix, fixer::Mode::Generate | fixer::Mode::Apply) {
+                    let fix = if matches!(self.autofix, fixer::Mode::Generate | fixer::Mode::Apply)
+                    {
                         let deleted: Vec<&Stmt> = self
                             .deletions
                             .iter()
@@ -1776,14 +1807,22 @@ impl<'a> Checker<'a> {
                         };
 
                         match removal_fn(&mut self.locator, &full_names, child, parent, &deleted) {
-                            Ok(fix) => {
-                                if fix.content.is_empty() || fix.content == "pass" {
-                                    self.deletions.insert(defined_by);
-                                }
-                                check.amend(fix)
+                            Ok(fix) => Some(fix),
+                            Err(e) => {
+                                error!("Failed to fix unused imports: {}", e);
+                                None
                             }
-                            Err(e) => error!("Failed to fix unused imports: {}", e),
                         }
+                    } else {
+                        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);
                     }
 
                     self.checks.push(check);
@@ -1793,7 +1832,7 @@ impl<'a> Checker<'a> {
     }
 
     fn check_builtin_shadowing(&mut self, name: &str, location: Range, is_attribute: bool) {
-        let scope = &self.scopes[*(self.scope_stack.last().expect("No current scope found."))];
+        let scope = self.current_scope();
 
         // flake8-builtins
         if is_attribute && matches!(scope.kind, ScopeKind::Class) {

src/check_lines.rs

@@ -1,8 +1,8 @@
 use std::collections::BTreeMap;
 
-use crate::ast::types::Range;
 use rustpython_parser::ast::Location;
 
+use crate::ast::types::Range;
 use crate::autofix::fixer;
 use crate::checks::{Check, CheckCode, CheckKind, Fix};
 use crate::noqa;
@@ -66,12 +66,12 @@ pub fn check_lines(
 
                 match noqa {
                     (Directive::All(_, _), matches) => {
-                        matches.push(check.kind.code().as_str());
+                        matches.push(check.kind.code().as_ref());
                         ignored.push(index)
                     }
                     (Directive::Codes(_, _, codes), matches) => {
-                        if codes.contains(&check.kind.code().as_str()) {
-                            matches.push(check.kind.code().as_str());
+                        if codes.contains(&check.kind.code().as_ref()) {
+                            matches.push(check.kind.code().as_ref());
                             ignored.push(index);
                         }
                     }
@@ -98,11 +98,11 @@ pub fn check_lines(
 
                 match noqa {
                     (Directive::All(_, _), matches) => {
-                        matches.push(check.kind.code().as_str());
+                        matches.push(check.kind.code().as_ref());
                     }
                     (Directive::Codes(_, _, codes), matches) => {
-                        if codes.contains(&check.kind.code().as_str()) {
-                            matches.push(check.kind.code().as_str());
+                        if codes.contains(&check.kind.code().as_ref()) {
+                            matches.push(check.kind.code().as_ref());
                         } else {
                             line_checks.push(check);
                         }
@@ -113,6 +113,45 @@ pub fn check_lines(
         }
     }
 
+    // Enforce newlines at end of files.
+    if settings.enabled.contains(&CheckCode::W292) && !contents.ends_with('\n') {
+        // Note: if `lines.last()` is `None`, then `contents` is empty (and so we don't want to
+        // raise W292 anyway).
+        if let Some(line) = lines.last() {
+            let lineno = lines.len() - 1;
+            let noqa_lineno = noqa_line_for
+                .get(lineno)
+                .map(|lineno| lineno - 1)
+                .unwrap_or(lineno);
+
+            let noqa = noqa_directives
+                .entry(noqa_lineno)
+                .or_insert_with(|| (noqa::extract_noqa_directive(lines[noqa_lineno]), vec![]));
+
+            let check = Check::new(
+                CheckKind::NoNewLineAtEndOfFile,
+                Range {
+                    location: Location::new(lines.len(), line.len() + 1),
+                    end_location: Location::new(lines.len(), line.len() + 1),
+                },
+            );
+
+            match noqa {
+                (Directive::All(_, _), matches) => {
+                    matches.push(check.kind.code().as_ref());
+                }
+                (Directive::Codes(_, _, codes), matches) => {
+                    if codes.contains(&check.kind.code().as_ref()) {
+                        matches.push(check.kind.code().as_ref());
+                    } else {
+                        line_checks.push(check);
+                    }
+                }
+                (Directive::None, _) => line_checks.push(check),
+            }
+        }
+    }
+
     // Enforce that the noqa directive was actually used.
     if enforce_noqa {
         for (row, (directive, matches)) in noqa_directives {

src/checks.rs

@@ -1,13 +1,13 @@
-use std::str::FromStr;
-
-use crate::ast::types::Range;
-use anyhow::Result;
 use itertools::Itertools;
 use rustpython_parser::ast::Location;
 use serde::{Deserialize, Serialize};
+use strum_macros::{AsRefStr, EnumIter, EnumString};
 
-pub const DEFAULT_CHECK_CODES: [CheckCode; 42] = [
-    // pycodestyle
+use crate::ast::checks::Primitive;
+use crate::ast::types::Range;
+
+pub const DEFAULT_CHECK_CODES: [CheckCode; 43] = [
+    // pycodestyle errors
     CheckCode::E402,
     CheckCode::E501,
     CheckCode::E711,
@@ -22,6 +22,8 @@ pub const DEFAULT_CHECK_CODES: [CheckCode; 42] = [
     CheckCode::E743,
     CheckCode::E902,
     CheckCode::E999,
+    // pycodestyle warnings
+    CheckCode::W292,
     // pyflakes
     CheckCode::F401,
     CheckCode::F402,
@@ -53,72 +55,22 @@ pub const DEFAULT_CHECK_CODES: [CheckCode; 42] = [
     CheckCode::F901,
 ];
 
-pub const ALL_CHECK_CODES: [CheckCode; 52] = [
-    // pycodestyle
-    CheckCode::E402,
-    CheckCode::E501,
-    CheckCode::E711,
-    CheckCode::E712,
-    CheckCode::E713,
-    CheckCode::E714,
-    CheckCode::E721,
-    CheckCode::E722,
-    CheckCode::E731,
-    CheckCode::E741,
-    CheckCode::E742,
-    CheckCode::E743,
-    CheckCode::E902,
-    CheckCode::E999,
-    // pyflakes
-    CheckCode::F401,
-    CheckCode::F402,
-    CheckCode::F403,
-    CheckCode::F404,
-    CheckCode::F405,
-    CheckCode::F406,
-    CheckCode::F407,
-    CheckCode::F541,
-    CheckCode::F601,
-    CheckCode::F602,
-    CheckCode::F621,
-    CheckCode::F622,
-    CheckCode::F631,
-    CheckCode::F632,
-    CheckCode::F633,
-    CheckCode::F634,
-    CheckCode::F701,
-    CheckCode::F702,
-    CheckCode::F704,
-    CheckCode::F706,
-    CheckCode::F707,
-    CheckCode::F722,
-    CheckCode::F821,
-    CheckCode::F822,
-    CheckCode::F823,
-    CheckCode::F831,
-    CheckCode::F841,
-    CheckCode::F901,
-    // flake8-builtins
-    CheckCode::A001,
-    CheckCode::A002,
-    CheckCode::A003,
-    // flake8-super
-    CheckCode::SPR001,
-    // flake8-print
-    CheckCode::T201,
-    CheckCode::T203,
-    // pyupgrade
-    CheckCode::U001,
-    // Refactor
-    CheckCode::R001,
-    CheckCode::R002,
-    // Meta
-    CheckCode::M001,
-];
-
-#[derive(Debug, PartialEq, Eq, Clone, Serialize, Deserialize, Hash, PartialOrd, Ord)]
+#[derive(
+    AsRefStr,
+    EnumIter,
+    EnumString,
+    Debug,
+    PartialEq,
+    Eq,
+    Clone,
+    Serialize,
+    Deserialize,
+    Hash,
+    PartialOrd,
+    Ord,
+)]
 pub enum CheckCode {
-    // pycodestyle
+    // pycodestyle errors
     E402,
     E501,
     E711,
@@ -133,6 +85,8 @@ pub enum CheckCode {
     E743,
     E902,
     E999,
+    // pycodestyle warnings
+    W292,
     // pyflakes
     F401,
     F402,
@@ -166,6 +120,16 @@ pub enum CheckCode {
     A001,
     A002,
     A003,
+    // flake8-comprehensions
+    C400,
+    C401,
+    C402,
+    C403,
+    C404,
+    C405,
+    C406,
+    C408,
+    C415,
     // flake8-super
     SPR001,
     // flake8-print
@@ -173,146 +137,108 @@ pub enum CheckCode {
     T203,
     // pyupgrade
     U001,
-    // Refactor
-    R001,
-    R002,
+    U002,
+    U003,
+    U004,
+    U005,
+    U006,
+    U007,
     // Meta
     M001,
 }
 
-impl FromStr for CheckCode {
-    type Err = anyhow::Error;
+#[allow(clippy::upper_case_acronyms)]
+pub enum LintSource {
+    AST,
+    Lines,
+    FileSystem,
+}
 
-    fn from_str(s: &str) -> Result<Self> {
-        match s {
-            // pycodestyle
-            "E402" => Ok(CheckCode::E402),
-            "E501" => Ok(CheckCode::E501),
-            "E711" => Ok(CheckCode::E711),
-            "E712" => Ok(CheckCode::E712),
-            "E713" => Ok(CheckCode::E713),
-            "E714" => Ok(CheckCode::E714),
-            "E721" => Ok(CheckCode::E721),
-            "E722" => Ok(CheckCode::E722),
-            "E731" => Ok(CheckCode::E731),
-            "E741" => Ok(CheckCode::E741),
-            "E742" => Ok(CheckCode::E742),
-            "E743" => Ok(CheckCode::E743),
-            "E902" => Ok(CheckCode::E902),
-            "E999" => Ok(CheckCode::E999),
-            // pyflakes
-            "F401" => Ok(CheckCode::F401),
-            "F402" => Ok(CheckCode::F402),
-            "F403" => Ok(CheckCode::F403),
-            "F404" => Ok(CheckCode::F404),
-            "F405" => Ok(CheckCode::F405),
-            "F406" => Ok(CheckCode::F406),
-            "F407" => Ok(CheckCode::F407),
-            "F541" => Ok(CheckCode::F541),
-            "F601" => Ok(CheckCode::F601),
-            "F602" => Ok(CheckCode::F602),
-            "F621" => Ok(CheckCode::F621),
-            "F622" => Ok(CheckCode::F622),
-            "F631" => Ok(CheckCode::F631),
-            "F632" => Ok(CheckCode::F632),
-            "F633" => Ok(CheckCode::F633),
-            "F634" => Ok(CheckCode::F634),
-            "F701" => Ok(CheckCode::F701),
-            "F702" => Ok(CheckCode::F702),
-            "F704" => Ok(CheckCode::F704),
-            "F706" => Ok(CheckCode::F706),
-            "F707" => Ok(CheckCode::F707),
-            "F722" => Ok(CheckCode::F722),
-            "F821" => Ok(CheckCode::F821),
-            "F822" => Ok(CheckCode::F822),
-            "F823" => Ok(CheckCode::F823),
-            "F831" => Ok(CheckCode::F831),
-            "F841" => Ok(CheckCode::F841),
-            "F901" => Ok(CheckCode::F901),
-            // flake8-builtins
-            "A001" => Ok(CheckCode::A001),
-            "A002" => Ok(CheckCode::A002),
-            "A003" => Ok(CheckCode::A003),
-            // flake8-super
-            "SPR001" => Ok(CheckCode::SPR001),
-            // pyupgrade
-            "U001" => Ok(CheckCode::U001),
-            // Refactor
-            "R001" => Ok(CheckCode::R001),
-            "R002" => Ok(CheckCode::R002),
-            // Meta
-            "M001" => Ok(CheckCode::M001),
-            _ => Err(anyhow::anyhow!("Unknown check code: {s}")),
-        }
-    }
+#[derive(Debug, PartialEq, Eq, Serialize, Deserialize)]
+pub enum RejectedCmpop {
+    Eq,
+    NotEq,
+}
+
+#[derive(AsRefStr, Debug, PartialEq, Eq, Serialize, Deserialize)]
+pub enum CheckKind {
+    // pycodestyle errors
+    AmbiguousClassName(String),
+    AmbiguousFunctionName(String),
+    AmbiguousVariableName(String),
+    AssertTuple,
+    BreakOutsideLoop,
+    ContinueOutsideLoop,
+    DefaultExceptNotLast,
+    DoNotAssignLambda,
+    DoNotUseBareExcept,
+    DuplicateArgumentName,
+    ExpressionsInStarAssignment,
+    FStringMissingPlaceholders,
+    ForwardAnnotationSyntaxError(String),
+    FutureFeatureNotDefined(String),
+    IOError(String),
+    IfTuple,
+    ImportShadowedByLoopVar(String, usize),
+    ImportStarNotPermitted(String),
+    ImportStarUsage(String, Vec<String>),
+    ImportStarUsed(String),
+    InvalidPrintSyntax,
+    IsLiteral,
+    LateFutureImport,
+    LineTooLong(usize, usize),
+    ModuleImportNotAtTopOfFile,
+    MultiValueRepeatedKeyLiteral,
+    MultiValueRepeatedKeyVariable(String),
+    NoneComparison(RejectedCmpop),
+    NotInTest,
+    NotIsTest,
+    RaiseNotImplemented,
+    ReturnOutsideFunction,
+    SyntaxError(String),
+    TrueFalseComparison(bool, RejectedCmpop),
+    TwoStarredExpressions,
+    TypeComparison,
+    UndefinedExport(String),
+    UndefinedLocal(String),
+    UndefinedName(String),
+    UnusedImport(Vec<String>),
+    UnusedVariable(String),
+    YieldOutsideFunction,
+    // pycodestyle warnings
+    NoNewLineAtEndOfFile,
+    // flake8-builtin
+    BuiltinVariableShadowing(String),
+    BuiltinArgumentShadowing(String),
+    BuiltinAttributeShadowing(String),
+    // flakes8-comprehensions
+    UnnecessaryGeneratorList,
+    UnnecessaryGeneratorSet,
+    UnnecessaryGeneratorDict,
+    UnnecessaryListComprehensionSet,
+    UnnecessaryListComprehensionDict,
+    UnnecessaryLiteralSet(String),
+    UnnecessaryLiteralDict(String),
+    UnnecessaryCollectionCall(String),
+    UnnecessarySubscriptReversal(String),
+    // flake8-super
+    SuperCallWithParameters,
+    // flake8-print
+    PrintFound,
+    PPrintFound,
+    // pyupgrade
+    TypeOfPrimitive(Primitive),
+    UnnecessaryAbspath,
+    UselessMetaclassType,
+    NoAssertEquals,
+    UselessObjectInheritance(String),
+    UsePEP585Annotation(String),
+    UsePEP604Annotation,
+    // Meta
+    UnusedNOQA(Option<String>),
 }
 
 impl CheckCode {
-    pub fn as_str(&self) -> &str {
-        match self {
-            // pycodestyle
-            CheckCode::E402 => "E402",
-            CheckCode::E501 => "E501",
-            CheckCode::E711 => "E711",
-            CheckCode::E712 => "E712",
-            CheckCode::E713 => "E713",
-            CheckCode::E714 => "E714",
-            CheckCode::E721 => "E721",
-            CheckCode::E722 => "E722",
-            CheckCode::E731 => "E731",
-            CheckCode::E741 => "E741",
-            CheckCode::E742 => "E742",
-            CheckCode::E743 => "E743",
-            CheckCode::E902 => "E902",
-            CheckCode::E999 => "E999",
-            // pyflakes
-            CheckCode::F401 => "F401",
-            CheckCode::F402 => "F402",
-            CheckCode::F403 => "F403",
-            CheckCode::F404 => "F404",
-            CheckCode::F405 => "F405",
-            CheckCode::F406 => "F406",
-            CheckCode::F407 => "F407",
-            CheckCode::F541 => "F541",
-            CheckCode::F601 => "F601",
-            CheckCode::F602 => "F602",
-            CheckCode::F621 => "F621",
-            CheckCode::F622 => "F622",
-            CheckCode::F631 => "F631",
-            CheckCode::F632 => "F632",
-            CheckCode::F633 => "F633",
-            CheckCode::F634 => "F634",
-            CheckCode::F701 => "F701",
-            CheckCode::F702 => "F702",
-            CheckCode::F704 => "F704",
-            CheckCode::F706 => "F706",
-            CheckCode::F707 => "F707",
-            CheckCode::F722 => "F722",
-            CheckCode::F821 => "F821",
-            CheckCode::F822 => "F822",
-            CheckCode::F823 => "F823",
-            CheckCode::F831 => "F831",
-            CheckCode::F841 => "F841",
-            CheckCode::F901 => "F901",
-            // flake8-builtins
-            CheckCode::A001 => "A001",
-            CheckCode::A002 => "A002",
-            CheckCode::A003 => "A003",
-            // flake8-super
-            CheckCode::SPR001 => "SPR001",
-            // flake8-print
-            CheckCode::T201 => "T201",
-            CheckCode::T203 => "T203",
-            // pyupgrade
-            CheckCode::U001 => "U001",
-            // Refactor
-            CheckCode::R001 => "R001",
-            CheckCode::R002 => "R002",
-            // Meta
-            CheckCode::M001 => "M001",
-        }
-    }
-
     /// The source for the check (either the AST, the filesystem, or the physical lines).
     pub fn lint_source(&self) -> &'static LintSource {
         match self {
@@ -325,7 +251,7 @@ impl CheckCode {
     /// A placeholder representation of the CheckKind for the check.
     pub fn kind(&self) -> CheckKind {
         match self {
-            // pycodestyle
+            // pycodestyle errors
             CheckCode::E402 => CheckKind::ModuleImportNotAtTopOfFile,
             CheckCode::E501 => CheckKind::LineTooLong(89, 88),
             CheckCode::E711 => CheckKind::NoneComparison(RejectedCmpop::Eq),
@@ -340,8 +266,10 @@ impl CheckCode {
             CheckCode::E743 => CheckKind::AmbiguousFunctionName("...".to_string()),
             CheckCode::E902 => CheckKind::IOError("IOError: `...`".to_string()),
             CheckCode::E999 => CheckKind::SyntaxError("`...`".to_string()),
+            // pycodestyle warnings
+            CheckCode::W292 => CheckKind::NoNewLineAtEndOfFile,
             // pyflakes
-            CheckCode::F401 => CheckKind::UnusedImport("...".to_string()),
+            CheckCode::F401 => CheckKind::UnusedImport(vec!["...".to_string()]),
             CheckCode::F402 => CheckKind::ImportShadowedByLoopVar("...".to_string(), 1),
             CheckCode::F403 => CheckKind::ImportStarUsed("...".to_string()),
             CheckCode::F404 => CheckKind::LateFutureImport,
@@ -375,6 +303,20 @@ impl CheckCode {
             CheckCode::A001 => CheckKind::BuiltinVariableShadowing("...".to_string()),
             CheckCode::A002 => CheckKind::BuiltinArgumentShadowing("...".to_string()),
             CheckCode::A003 => CheckKind::BuiltinAttributeShadowing("...".to_string()),
+            // flake8-comprehensions
+            CheckCode::C400 => CheckKind::UnnecessaryGeneratorList,
+            CheckCode::C401 => CheckKind::UnnecessaryGeneratorSet,
+            CheckCode::C402 => CheckKind::UnnecessaryGeneratorDict,
+            CheckCode::C403 => CheckKind::UnnecessaryListComprehensionSet,
+            CheckCode::C404 => CheckKind::UnnecessaryListComprehensionDict,
+            CheckCode::C405 => CheckKind::UnnecessaryLiteralSet("<list/tuple>".to_string()),
+            CheckCode::C406 => CheckKind::UnnecessaryLiteralDict("<list/tuple>".to_string()),
+            CheckCode::C408 => {
+                CheckKind::UnnecessaryCollectionCall("<dict/list/tuple>".to_string())
+            }
+            CheckCode::C415 => {
+                CheckKind::UnnecessarySubscriptReversal("<reversed/set/sorted>".to_string())
+            }
             // flake8-super
             CheckCode::SPR001 => CheckKind::SuperCallWithParameters,
             // flake8-print
@@ -382,155 +324,23 @@ impl CheckCode {
             CheckCode::T203 => CheckKind::PPrintFound,
             // pyupgrade
             CheckCode::U001 => CheckKind::UselessMetaclassType,
-            // Refactor
-            CheckCode::R001 => CheckKind::UselessObjectInheritance("...".to_string()),
-            CheckCode::R002 => CheckKind::NoAssertEquals,
+            CheckCode::U002 => CheckKind::UnnecessaryAbspath,
+            CheckCode::U003 => CheckKind::TypeOfPrimitive(Primitive::Str),
+            CheckCode::U004 => CheckKind::UselessObjectInheritance("...".to_string()),
+            CheckCode::U005 => CheckKind::NoAssertEquals,
+            CheckCode::U006 => CheckKind::UsePEP585Annotation("List".to_string()),
+            CheckCode::U007 => CheckKind::UsePEP604Annotation,
             // Meta
             CheckCode::M001 => CheckKind::UnusedNOQA(None),
         }
     }
 }
 
-#[allow(clippy::upper_case_acronyms)]
-pub enum LintSource {
-    AST,
-    Lines,
-    FileSystem,
-}
-
-#[derive(Debug, PartialEq, Eq, Serialize, Deserialize)]
-pub enum RejectedCmpop {
-    Eq,
-    NotEq,
-}
-
-#[derive(Debug, PartialEq, Eq, Serialize, Deserialize)]
-pub enum CheckKind {
-    AmbiguousClassName(String),
-    AmbiguousFunctionName(String),
-    AmbiguousVariableName(String),
-    AssertTuple,
-    BreakOutsideLoop,
-    ContinueOutsideLoop,
-    DefaultExceptNotLast,
-    DoNotAssignLambda,
-    DoNotUseBareExcept,
-    DuplicateArgumentName,
-    ExpressionsInStarAssignment,
-    FStringMissingPlaceholders,
-    ForwardAnnotationSyntaxError(String),
-    FutureFeatureNotDefined(String),
-    IOError(String),
-    IfTuple,
-    ImportShadowedByLoopVar(String, usize),
-    ImportStarNotPermitted(String),
-    ImportStarUsage(String, Vec<String>),
-    ImportStarUsed(String),
-    InvalidPrintSyntax,
-    IsLiteral,
-    LateFutureImport,
-    LineTooLong(usize, usize),
-    ModuleImportNotAtTopOfFile,
-    MultiValueRepeatedKeyLiteral,
-    MultiValueRepeatedKeyVariable(String),
-    NoAssertEquals,
-    NoneComparison(RejectedCmpop),
-    NotInTest,
-    NotIsTest,
-    RaiseNotImplemented,
-    ReturnOutsideFunction,
-    SyntaxError(String),
-    TrueFalseComparison(bool, RejectedCmpop),
-    TwoStarredExpressions,
-    TypeComparison,
-    UndefinedExport(String),
-    UndefinedLocal(String),
-    UndefinedName(String),
-    UnusedImport(String),
-    UnusedNOQA(Option<String>),
-    UnusedVariable(String),
-    UselessMetaclassType,
-    UselessObjectInheritance(String),
-    YieldOutsideFunction,
-    // flake8-builtin
-    BuiltinVariableShadowing(String),
-    BuiltinArgumentShadowing(String),
-    BuiltinAttributeShadowing(String),
-    // flake8-super
-    SuperCallWithParameters,
-    // flake8-print
-    PrintFound,
-    PPrintFound,
-}
-
 impl CheckKind {
-    /// The name of the check.
-    pub fn name(&self) -> &'static str {
-        match self {
-            CheckKind::AmbiguousClassName(_) => "AmbiguousClassName",
-            CheckKind::AmbiguousFunctionName(_) => "AmbiguousFunctionName",
-            CheckKind::AmbiguousVariableName(_) => "AmbiguousVariableName",
-            CheckKind::AssertTuple => "AssertTuple",
-            CheckKind::BreakOutsideLoop => "BreakOutsideLoop",
-            CheckKind::ContinueOutsideLoop => "ContinueOutsideLoop",
-            CheckKind::DefaultExceptNotLast => "DefaultExceptNotLast",
-            CheckKind::DoNotAssignLambda => "DoNotAssignLambda",
-            CheckKind::DoNotUseBareExcept => "DoNotUseBareExcept",
-            CheckKind::DuplicateArgumentName => "DuplicateArgumentName",
-            CheckKind::ExpressionsInStarAssignment => "ExpressionsInStarAssignment",
-            CheckKind::FStringMissingPlaceholders => "FStringMissingPlaceholders",
-            CheckKind::ForwardAnnotationSyntaxError(_) => "ForwardAnnotationSyntaxError",
-            CheckKind::FutureFeatureNotDefined(_) => "FutureFeatureNotDefined",
-            CheckKind::IOError(_) => "IOError",
-            CheckKind::IfTuple => "IfTuple",
-            CheckKind::ImportShadowedByLoopVar(_, _) => "ImportShadowedByLoopVar",
-            CheckKind::ImportStarNotPermitted(_) => "ImportStarNotPermitted",
-            CheckKind::ImportStarUsage(_, _) => "ImportStarUsage",
-            CheckKind::ImportStarUsed(_) => "ImportStarUsed",
-            CheckKind::InvalidPrintSyntax => "InvalidPrintSyntax",
-            CheckKind::IsLiteral => "IsLiteral",
-            CheckKind::LateFutureImport => "LateFutureImport",
-            CheckKind::LineTooLong(_, _) => "LineTooLong",
-            CheckKind::ModuleImportNotAtTopOfFile => "ModuleImportNotAtTopOfFile",
-            CheckKind::MultiValueRepeatedKeyLiteral => "MultiValueRepeatedKeyLiteral",
-            CheckKind::MultiValueRepeatedKeyVariable(_) => "MultiValueRepeatedKeyVariable",
-            CheckKind::NoneComparison(_) => "NoneComparison",
-            CheckKind::NotInTest => "NotInTest",
-            CheckKind::NotIsTest => "NotIsTest",
-            CheckKind::RaiseNotImplemented => "RaiseNotImplemented",
-            CheckKind::ReturnOutsideFunction => "ReturnOutsideFunction",
-            CheckKind::SyntaxError(_) => "SyntaxError",
-            CheckKind::TrueFalseComparison(_, _) => "TrueFalseComparison",
-            CheckKind::TwoStarredExpressions => "TwoStarredExpressions",
-            CheckKind::TypeComparison => "TypeComparison",
-            CheckKind::UndefinedExport(_) => "UndefinedExport",
-            CheckKind::UndefinedLocal(_) => "UndefinedLocal",
-            CheckKind::UndefinedName(_) => "UndefinedName",
-            CheckKind::UnusedImport(_) => "UnusedImport",
-            CheckKind::UnusedVariable(_) => "UnusedVariable",
-            CheckKind::YieldOutsideFunction => "YieldOutsideFunction",
-            // flake8-builtins
-            CheckKind::BuiltinVariableShadowing(_) => "BuiltinVariableShadowing",
-            CheckKind::BuiltinArgumentShadowing(_) => "BuiltinArgumentShadowing",
-            CheckKind::BuiltinAttributeShadowing(_) => "BuiltinAttributeShadowing",
-            // flake8-super
-            CheckKind::SuperCallWithParameters => "SuperCallWithParameters",
-            // flake8-print
-            CheckKind::PrintFound => "PrintFound",
-            CheckKind::PPrintFound => "PPrintFound",
-            // pyupgrade
-            CheckKind::UselessMetaclassType => "UselessMetaclassType",
-            // Refactor
-            CheckKind::NoAssertEquals => "NoAssertEquals",
-            CheckKind::UselessObjectInheritance(_) => "UselessObjectInheritance",
-            // Meta
-            CheckKind::UnusedNOQA(_) => "UnusedNOQA",
-        }
-    }
-
     /// A four-letter shorthand code for the check.
     pub fn code(&self) -> &'static CheckCode {
         match self {
+            // pycodestyle errors
             CheckKind::AmbiguousClassName(_) => &CheckCode::E742,
             CheckKind::AmbiguousFunctionName(_) => &CheckCode::E743,
             CheckKind::AmbiguousVariableName(_) => &CheckCode::E741,
@@ -573,20 +383,35 @@ impl CheckKind {
             CheckKind::UnusedImport(_) => &CheckCode::F401,
             CheckKind::UnusedVariable(_) => &CheckCode::F841,
             CheckKind::YieldOutsideFunction => &CheckCode::F704,
+            // pycodestyle warnings
+            CheckKind::NoNewLineAtEndOfFile => &CheckCode::W292,
             // flake8-builtins
             CheckKind::BuiltinVariableShadowing(_) => &CheckCode::A001,
             CheckKind::BuiltinArgumentShadowing(_) => &CheckCode::A002,
             CheckKind::BuiltinAttributeShadowing(_) => &CheckCode::A003,
+            // flake8-comprehensions
+            CheckKind::UnnecessaryGeneratorList => &CheckCode::C400,
+            CheckKind::UnnecessaryGeneratorSet => &CheckCode::C401,
+            CheckKind::UnnecessaryGeneratorDict => &CheckCode::C402,
+            CheckKind::UnnecessaryListComprehensionSet => &CheckCode::C403,
+            CheckKind::UnnecessaryListComprehensionDict => &CheckCode::C404,
+            CheckKind::UnnecessaryLiteralSet(_) => &CheckCode::C405,
+            CheckKind::UnnecessaryLiteralDict(_) => &CheckCode::C406,
+            CheckKind::UnnecessaryCollectionCall(_) => &CheckCode::C408,
+            CheckKind::UnnecessarySubscriptReversal(_) => &CheckCode::C415,
             // flake8-super
             CheckKind::SuperCallWithParameters => &CheckCode::SPR001,
             // flake8-print
             CheckKind::PrintFound => &CheckCode::T201,
             CheckKind::PPrintFound => &CheckCode::T203,
             // pyupgrade
+            CheckKind::TypeOfPrimitive(_) => &CheckCode::U003,
+            CheckKind::UnnecessaryAbspath => &CheckCode::U002,
             CheckKind::UselessMetaclassType => &CheckCode::U001,
-            // Refactor
-            CheckKind::NoAssertEquals => &CheckCode::R002,
-            CheckKind::UselessObjectInheritance(_) => &CheckCode::R001,
+            CheckKind::NoAssertEquals => &CheckCode::U005,
+            CheckKind::UsePEP585Annotation(_) => &CheckCode::U006,
+            CheckKind::UsePEP604Annotation => &CheckCode::U007,
+            CheckKind::UselessObjectInheritance(_) => &CheckCode::U004,
             // Meta
             CheckKind::UnusedNOQA(_) => &CheckCode::M001,
         }
@@ -595,6 +420,7 @@ impl CheckKind {
     /// The body text for the check.
     pub fn body(&self) -> String {
         match self {
+            // pycodestyle errors
             CheckKind::AmbiguousClassName(name) => {
                 format!("Ambiguous class name: `{}`", name)
             }
@@ -712,14 +538,18 @@ impl CheckKind {
             CheckKind::UndefinedName(name) => {
                 format!("Undefined name `{name}`")
             }
-            CheckKind::UnusedImport(name) => format!("`{name}` imported but unused"),
+            CheckKind::UnusedImport(names) => {
+                let names = names.iter().map(|name| format!("`{name}`")).join(", ");
+                format!("{names} imported but unused")
+            }
             CheckKind::UnusedVariable(name) => {
                 format!("Local variable `{name}` is assigned to but never used")
             }
             CheckKind::YieldOutsideFunction => {
                 "`yield` or `yield from` statement outside of a function/method".to_string()
             }
-
+            // pycodestyle warnings
+            CheckKind::NoNewLineAtEndOfFile => "No newline at end of file".to_string(),
             // flake8-builtins
             CheckKind::BuiltinVariableShadowing(name) => {
                 format!("Variable `{name}` is shadowing a python builtin")
@@ -730,6 +560,34 @@ impl CheckKind {
             CheckKind::BuiltinAttributeShadowing(name) => {
                 format!("Class attribute `{name}` is shadowing a python builtin")
             }
+            // flake8-comprehensions
+            CheckKind::UnnecessaryGeneratorList => {
+                "Unnecessary generator - rewrite as a list comprehension".to_string()
+            }
+            CheckKind::UnnecessaryGeneratorSet => {
+                "Unnecessary generator - rewrite as a set comprehension".to_string()
+            }
+            CheckKind::UnnecessaryGeneratorDict => {
+                "Unnecessary generator - rewrite as a dict comprehension".to_string()
+            }
+            CheckKind::UnnecessaryListComprehensionSet => {
+                "Unnecessary list comprehension - rewrite as a set comprehension".to_string()
+            }
+            CheckKind::UnnecessaryListComprehensionDict => {
+                "Unnecessary list comprehension - rewrite as a dict comprehension".to_string()
+            }
+            CheckKind::UnnecessaryLiteralSet(obj_type) => {
+                format!("Unnecessary {obj_type} literal - rewrite as a set literal")
+            }
+            CheckKind::UnnecessaryLiteralDict(obj_type) => {
+                format!("Unnecessary {obj_type} literal - rewrite as a dict literal")
+            }
+            CheckKind::UnnecessaryCollectionCall(obj_type) => {
+                format!("Unnecessary {obj_type} call - rewrite as a literal")
+            }
+            CheckKind::UnnecessarySubscriptReversal(func) => {
+                format!("Unnecessary subscript reversal of iterable within {func}()")
+            }
             // flake8-super
             CheckKind::SuperCallWithParameters => {
                 "Use `super()` instead of `super(__class__, self)`".to_string()
@@ -738,14 +596,27 @@ impl CheckKind {
             CheckKind::PrintFound => "`print` found".to_string(),
             CheckKind::PPrintFound => "`pprint` found".to_string(),
             // pyupgrade
+            CheckKind::TypeOfPrimitive(primitive) => {
+                format!("Use `{}` instead of `type(...)`", primitive.builtin())
+            }
+            CheckKind::UnnecessaryAbspath => {
+                "`abspath(__file__)` is unnecessary in Python 3.9 and later".to_string()
+            }
             CheckKind::UselessMetaclassType => "`__metaclass__ = type` is implied".to_string(),
-            // Refactor
             CheckKind::NoAssertEquals => {
                 "`assertEquals` is deprecated, use `assertEqual` instead".to_string()
             }
             CheckKind::UselessObjectInheritance(name) => {
                 format!("Class `{name}` inherits from object")
             }
+            CheckKind::UsePEP585Annotation(name) => {
+                format!(
+                    "Use `{}` instead of `{}` for type annotations",
+                    name.to_lowercase(),
+                    name,
+                )
+            }
+            CheckKind::UsePEP604Annotation => "Use `X | Y` for type annotations".to_string(),
             // Meta
             CheckKind::UnusedNOQA(code) => match code {
                 None => "Unused `noqa` directive".to_string(),
@@ -762,10 +633,14 @@ impl CheckKind {
                 | CheckKind::PPrintFound
                 | CheckKind::PrintFound
                 | CheckKind::SuperCallWithParameters
+                | CheckKind::TypeOfPrimitive(_)
+                | CheckKind::UnnecessaryAbspath
                 | CheckKind::UnusedImport(_)
                 | CheckKind::UnusedNOQA(_)
                 | CheckKind::UselessMetaclassType
                 | CheckKind::UselessObjectInheritance(_)
+                | CheckKind::UsePEP585Annotation(_)
+                | CheckKind::UsePEP604Annotation
         )
     }
 }
@@ -800,3 +675,25 @@ impl Check {
         self.fix = Some(fix);
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use std::str::FromStr;
+
+    use anyhow::Result;
+    use strum::IntoEnumIterator;
+
+    use crate::checks::CheckCode;
+
+    #[test]
+    fn check_code_serialization() -> Result<()> {
+        for check_code in CheckCode::iter() {
+            assert!(
+                CheckCode::from_str(check_code.as_ref()).is_ok(),
+                "{:?} could not be round-trip serialized.",
+                check_code
+            );
+        }
+        Ok(())
+    }
+}

src/cli.rs

@@ -0,0 +1,136 @@
+use std::fmt;
+use std::path::PathBuf;
+
+use clap::{command, Parser};
+use log::warn;
+use regex::Regex;
+
+use crate::checks::CheckCode;
+use crate::printer::SerializationFormat;
+use crate::pyproject::StrCheckCodePair;
+use crate::settings::PythonVersion;
+use crate::RawSettings;
+
+#[derive(Debug, Parser)]
+#[command(author, about = "ruff: An extremely fast Python linter.")]
+#[command(version)]
+pub struct Cli {
+    #[arg(required = true)]
+    pub files: Vec<PathBuf>,
+    /// Enable verbose logging.
+    #[arg(short, long)]
+    pub verbose: bool,
+    /// Disable all logging (but still exit with status code "1" upon detecting errors).
+    #[arg(short, long)]
+    pub quiet: bool,
+    /// Exit with status code "0", even upon detecting errors.
+    #[arg(short, long)]
+    pub exit_zero: bool,
+    /// Run in watch mode by re-running whenever files change.
+    #[arg(short, long)]
+    pub watch: bool,
+    /// Attempt to automatically fix lint errors.
+    #[arg(short, long)]
+    pub fix: bool,
+    /// Disable cache reads.
+    #[arg(short, long)]
+    pub no_cache: bool,
+    /// List of error codes to enable.
+    #[arg(long, value_delimiter = ',')]
+    pub select: Vec<CheckCode>,
+    /// Like --select, but adds additional error codes on top of the selected ones.
+    #[arg(long, value_delimiter = ',')]
+    pub extend_select: Vec<CheckCode>,
+    /// List of error codes to ignore.
+    #[arg(long, value_delimiter = ',')]
+    pub ignore: Vec<CheckCode>,
+    /// Like --ignore, but adds additional error codes on top of the ignored ones.
+    #[arg(long, value_delimiter = ',')]
+    pub extend_ignore: Vec<CheckCode>,
+    /// List of paths, used to exclude files and/or directories from checks.
+    #[arg(long, value_delimiter = ',')]
+    pub exclude: Vec<String>,
+    /// Like --exclude, but adds additional files and directories on top of the excluded ones.
+    #[arg(long, value_delimiter = ',')]
+    pub extend_exclude: Vec<String>,
+    /// List of mappings from file pattern to code to exclude
+    #[arg(long, value_delimiter = ',')]
+    pub per_file_ignores: Vec<StrCheckCodePair>,
+    /// Output serialization format for error messages.
+    #[arg(long, value_enum, default_value_t=SerializationFormat::Text)]
+    pub format: SerializationFormat,
+    /// See the files ruff will be run against with the current settings.
+    #[arg(long)]
+    pub show_files: bool,
+    /// See ruff's settings.
+    #[arg(long)]
+    pub show_settings: bool,
+    /// Enable automatic additions of noqa directives to failing lines.
+    #[arg(long)]
+    pub add_noqa: bool,
+    /// Regular expression matching the name of dummy variables.
+    #[arg(long)]
+    pub dummy_variable_rgx: Option<Regex>,
+    /// The minimum Python version that should be supported.
+    #[arg(long)]
+    pub target_version: Option<PythonVersion>,
+    /// Round-trip auto-formatting.
+    // TODO(charlie): This should be a sub-command.
+    #[arg(long, hide = true)]
+    pub autoformat: bool,
+}
+
+pub enum Warnable {
+    Select,
+    ExtendSelect,
+}
+
+impl fmt::Display for Warnable {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            Warnable::Select => fmt.write_str("--select"),
+            Warnable::ExtendSelect => fmt.write_str("--extend-select"),
+        }
+    }
+}
+
+/// Warn the user if they attempt to enable a code that won't be respected.
+pub fn warn_on(
+    flag: Warnable,
+    codes: &Vec<CheckCode>,
+    cli_ignore: &Vec<CheckCode>,
+    cli_extend_ignore: &Vec<CheckCode>,
+    pyproject_settings: &RawSettings,
+    pyproject_path: &Option<PathBuf>,
+) {
+    for code in codes {
+        if !cli_ignore.is_empty() {
+            if cli_ignore.contains(code) {
+                warn!("{code:?} was passed to {flag}, but ignored via --ignore")
+            }
+        } else if pyproject_settings.ignore.contains(code) {
+            if let Some(path) = pyproject_path {
+                warn!(
+                    "{code:?} was passed to {flag}, but ignored by the `ignore` field in {}",
+                    path.to_string_lossy()
+                )
+            } else {
+                warn!("{code:?} was passed to {flag}, but ignored by the default `ignore` field",)
+            }
+        }
+        if !cli_extend_ignore.is_empty() {
+            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) {
+            if let Some(path) = pyproject_path {
+                warn!(
+                    "{code:?} was passed to {flag}, but ignored by the `extend_ignore` field in {}",
+                    path.to_string_lossy()
+                )
+            } else {
+                warn!("{code:?} was passed to {flag}, but ignored by the default `extend_ignore` field")
+            }
+        }
+    }
+}

src/code_gen.rs

@@ -547,7 +547,7 @@ impl SourceGenerator {
         Ok(())
     }
 
-    fn unparse_expr<U>(&mut self, ast: &Expr<U>, level: u8) -> fmt::Result {
+    pub fn unparse_expr<U>(&mut self, ast: &Expr<U>, level: u8) -> fmt::Result {
         macro_rules! opprec {
             ($opty:ident, $x:expr, $enu:path, $($var:ident($op:literal, $prec:ident)),*$(,)?) => {
                 match $x {

src/lib.rs

@@ -15,12 +15,14 @@ pub mod cache;
 pub mod check_ast;
 mod check_lines;
 pub mod checks;
+pub mod cli;
 pub mod code_gen;
 pub mod fs;
 pub mod linter;
 pub mod logging;
 pub mod message;
 mod noqa;
+mod plugins;
 pub mod printer;
 pub mod pyproject;
 mod python;
@@ -40,7 +42,7 @@ pub fn check(path: &Path, contents: &str) -> Result<Vec<Message>> {
         None => debug!("Unable to find pyproject.toml; using default settings..."),
     };
 
-    let settings = Settings::from_raw(RawSettings::from_pyproject(pyproject, project_root)?);
+    let settings = Settings::from_raw(RawSettings::from_pyproject(&pyproject, &project_root)?);
 
     // Tokenize once.
     let tokens: Vec<LexResult> = tokenize(contents);

src/linter.rs

@@ -339,6 +339,42 @@ mod tests {
         Ok(())
     }
 
+    #[test]
+    fn w292_0() -> Result<()> {
+        let mut checks = check_path(
+            Path::new("./resources/test/fixtures/W292_0.py"),
+            &settings::Settings::for_rule(CheckCode::W292),
+            &fixer::Mode::Generate,
+        )?;
+        checks.sort_by_key(|check| check.location);
+        insta::assert_yaml_snapshot!(checks);
+        Ok(())
+    }
+
+    #[test]
+    fn w292_1() -> Result<()> {
+        let mut checks = check_path(
+            Path::new("./resources/test/fixtures/W292_1.py"),
+            &settings::Settings::for_rule(CheckCode::W292),
+            &fixer::Mode::Generate,
+        )?;
+        checks.sort_by_key(|check| check.location);
+        insta::assert_yaml_snapshot!(checks);
+        Ok(())
+    }
+
+    #[test]
+    fn w292_2() -> Result<()> {
+        let mut checks = check_path(
+            Path::new("./resources/test/fixtures/W292_2.py"),
+            &settings::Settings::for_rule(CheckCode::W292),
+            &fixer::Mode::Generate,
+        )?;
+        checks.sort_by_key(|check| check.location);
+        insta::assert_yaml_snapshot!(checks);
+        Ok(())
+    }
+
     #[test]
     fn f401() -> Result<()> {
         let mut checks = check_path(
@@ -690,30 +726,6 @@ mod tests {
         Ok(())
     }
 
-    #[test]
-    fn r001() -> Result<()> {
-        let mut checks = check_path(
-            Path::new("./resources/test/fixtures/R001.py"),
-            &settings::Settings::for_rule(CheckCode::R001),
-            &fixer::Mode::Generate,
-        )?;
-        checks.sort_by_key(|check| check.location);
-        insta::assert_yaml_snapshot!(checks);
-        Ok(())
-    }
-
-    #[test]
-    fn r002() -> Result<()> {
-        let mut checks = check_path(
-            Path::new("./resources/test/fixtures/R002.py"),
-            &settings::Settings::for_rule(CheckCode::R002),
-            &fixer::Mode::Generate,
-        )?;
-        checks.sort_by_key(|check| check.location);
-        insta::assert_yaml_snapshot!(checks);
-        Ok(())
-    }
-
     #[test]
     fn init() -> Result<()> {
         let mut checks = check_path(
@@ -786,6 +798,114 @@ mod tests {
         Ok(())
     }
 
+    #[test]
+    fn c400() -> Result<()> {
+        let mut checks = check_path(
+            Path::new("./resources/test/fixtures/C400.py"),
+            &settings::Settings::for_rule(CheckCode::C400),
+            &fixer::Mode::Generate,
+        )?;
+        checks.sort_by_key(|check| check.location);
+        insta::assert_yaml_snapshot!(checks);
+        Ok(())
+    }
+
+    #[test]
+    fn c401() -> Result<()> {
+        let mut checks = check_path(
+            Path::new("./resources/test/fixtures/C401.py"),
+            &settings::Settings::for_rule(CheckCode::C401),
+            &fixer::Mode::Generate,
+        )?;
+        checks.sort_by_key(|check| check.location);
+        insta::assert_yaml_snapshot!(checks);
+        Ok(())
+    }
+
+    #[test]
+    fn c402() -> Result<()> {
+        let mut checks = check_path(
+            Path::new("./resources/test/fixtures/C402.py"),
+            &settings::Settings::for_rule(CheckCode::C402),
+            &fixer::Mode::Generate,
+        )?;
+        checks.sort_by_key(|check| check.location);
+        insta::assert_yaml_snapshot!(checks);
+        Ok(())
+    }
+
+    #[test]
+    fn c403() -> Result<()> {
+        let mut checks = check_path(
+            Path::new("./resources/test/fixtures/C403.py"),
+            &settings::Settings::for_rule(CheckCode::C403),
+            &fixer::Mode::Generate,
+        )?;
+        checks.sort_by_key(|check| check.location);
+        insta::assert_yaml_snapshot!(checks);
+        Ok(())
+    }
+
+    #[test]
+    fn c404() -> Result<()> {
+        let mut checks = check_path(
+            Path::new("./resources/test/fixtures/C404.py"),
+            &settings::Settings::for_rule(CheckCode::C404),
+            &fixer::Mode::Generate,
+        )?;
+        checks.sort_by_key(|check| check.location);
+        insta::assert_yaml_snapshot!(checks);
+        Ok(())
+    }
+
+    #[test]
+    fn c405() -> Result<()> {
+        let mut checks = check_path(
+            Path::new("./resources/test/fixtures/C405.py"),
+            &settings::Settings::for_rule(CheckCode::C405),
+            &fixer::Mode::Generate,
+        )?;
+        checks.sort_by_key(|check| check.location);
+        insta::assert_yaml_snapshot!(checks);
+        Ok(())
+    }
+
+    #[test]
+    fn c406() -> Result<()> {
+        let mut checks = check_path(
+            Path::new("./resources/test/fixtures/C406.py"),
+            &settings::Settings::for_rule(CheckCode::C406),
+            &fixer::Mode::Generate,
+        )?;
+        checks.sort_by_key(|check| check.location);
+        insta::assert_yaml_snapshot!(checks);
+        Ok(())
+    }
+
+    #[test]
+    fn c408() -> Result<()> {
+        let mut checks = check_path(
+            Path::new("./resources/test/fixtures/C408.py"),
+            &settings::Settings::for_rule(CheckCode::C408),
+            &fixer::Mode::Generate,
+        )?;
+        checks.sort_by_key(|check| check.location);
+        insta::assert_yaml_snapshot!(checks);
+        Ok(())
+    }
+
+    #[test]
+    fn c415() -> Result<()> {
+        let mut checks = check_path(
+            Path::new("./resources/test/fixtures/C415.py"),
+            &settings::Settings::for_rule(CheckCode::C415),
+            &fixer::Mode::Generate,
+        )?;
+        checks.sort_by_key(|check| check.location);
+        insta::assert_yaml_snapshot!(checks);
+        Ok(())
+    }
+
     #[test]
     fn spr001() -> Result<()> {
         let mut checks = check_path(
@@ -833,4 +953,76 @@ mod tests {
         insta::assert_yaml_snapshot!(checks);
         Ok(())
     }
+
+    #[test]
+    fn u002() -> Result<()> {
+        let mut checks = check_path(
+            Path::new("./resources/test/fixtures/U002.py"),
+            &settings::Settings::for_rule(CheckCode::U002),
+            &fixer::Mode::Generate,
+        )?;
+        checks.sort_by_key(|check| check.location);
+        insta::assert_yaml_snapshot!(checks);
+        Ok(())
+    }
+
+    #[test]
+    fn u003() -> Result<()> {
+        let mut checks = check_path(
+            Path::new("./resources/test/fixtures/U003.py"),
+            &settings::Settings::for_rule(CheckCode::U003),
+            &fixer::Mode::Generate,
+        )?;
+        checks.sort_by_key(|check| check.location);
+        insta::assert_yaml_snapshot!(checks);
+        Ok(())
+    }
+
+    #[test]
+    fn u004() -> Result<()> {
+        let mut checks = check_path(
+            Path::new("./resources/test/fixtures/U004.py"),
+            &settings::Settings::for_rule(CheckCode::U004),
+            &fixer::Mode::Generate,
+        )?;
+        checks.sort_by_key(|check| check.location);
+        insta::assert_yaml_snapshot!(checks);
+        Ok(())
+    }
+
+    #[test]
+    fn u005() -> Result<()> {
+        let mut checks = check_path(
+            Path::new("./resources/test/fixtures/U005.py"),
+            &settings::Settings::for_rule(CheckCode::U005),
+            &fixer::Mode::Generate,
+        )?;
+        checks.sort_by_key(|check| check.location);
+        insta::assert_yaml_snapshot!(checks);
+        Ok(())
+    }
+
+    #[test]
+    fn u006() -> Result<()> {
+        let mut checks = check_path(
+            Path::new("./resources/test/fixtures/U006.py"),
+            &settings::Settings::for_rule(CheckCode::U006),
+            &fixer::Mode::Generate,
+        )?;
+        checks.sort_by_key(|check| check.location);
+        insta::assert_yaml_snapshot!(checks);
+        Ok(())
+    }
+
+    #[test]
+    fn u007() -> Result<()> {
+        let mut checks = check_path(
+            Path::new("./resources/test/fixtures/U007.py"),
+            &settings::Settings::for_rule(CheckCode::U007),
+            &fixer::Mode::Generate,
+        )?;
+        checks.sort_by_key(|check| check.location);
+        insta::assert_yaml_snapshot!(checks);
+        Ok(())
+    }
 }

src/main.rs

@@ -5,98 +5,33 @@ use std::sync::mpsc::channel;
 use std::time::Instant;
 
 use anyhow::Result;
-use clap::{command, Parser};
+use clap::Parser;
 use colored::Colorize;
 use log::{debug, error};
 use notify::{raw_watcher, RecursiveMode, Watcher};
 use rayon::prelude::*;
-use regex::Regex;
 use walkdir::DirEntry;
 
-use ::ruff::cache;
-use ::ruff::checks::CheckCode;
-use ::ruff::checks::CheckKind;
-use ::ruff::fs::iter_python_files;
-use ::ruff::linter::add_noqa_to_path;
-use ::ruff::linter::lint_path;
-use ::ruff::logging::set_up_logging;
-use ::ruff::message::Message;
-use ::ruff::printer::{Printer, SerializationFormat};
-use ::ruff::pyproject::{self, StrCheckCodePair};
-use ::ruff::settings::CurrentSettings;
-use ::ruff::settings::{FilePattern, PerFileIgnore, Settings};
-use ::ruff::tell_user;
+use ruff::cache;
+use ruff::checks::CheckCode;
+use ruff::checks::CheckKind;
+use ruff::cli::{warn_on, Cli, Warnable};
+use ruff::fs::iter_python_files;
+use ruff::linter::add_noqa_to_path;
 use ruff::linter::autoformat_path;
+use ruff::linter::lint_path;
+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::tell_user;
 
 const CARGO_PKG_NAME: &str = env!("CARGO_PKG_NAME");
 const CARGO_PKG_VERSION: &str = env!("CARGO_PKG_VERSION");
 
-#[derive(Debug, Parser)]
-#[command(author, about = "ruff: An extremely fast Python linter.")]
-#[command(version)]
-struct Cli {
-    #[arg(required = true)]
-    files: Vec<PathBuf>,
-    /// Enable verbose logging.
-    #[arg(short, long)]
-    verbose: bool,
-    /// Disable all logging (but still exit with status code "1" upon detecting errors).
-    #[arg(short, long)]
-    quiet: bool,
-    /// Exit with status code "0", even upon detecting errors.
-    #[arg(short, long)]
-    exit_zero: bool,
-    /// Run in watch mode by re-running whenever files change.
-    #[arg(short, long)]
-    watch: bool,
-    /// Attempt to automatically fix lint errors.
-    #[arg(short, long)]
-    fix: bool,
-    /// Disable cache reads.
-    #[arg(short, long)]
-    no_cache: bool,
-    /// List of error codes to enable.
-    #[arg(long, value_delimiter = ',')]
-    select: Vec<CheckCode>,
-    /// Like --select, but adds additional error codes on top of the selected ones.
-    #[arg(long, value_delimiter = ',')]
-    extend_select: Vec<CheckCode>,
-    /// List of error codes to ignore.
-    #[arg(long, value_delimiter = ',')]
-    ignore: Vec<CheckCode>,
-    /// Like --ignore, but adds additional error codes on top of the ignored ones.
-    #[arg(long, value_delimiter = ',')]
-    extend_ignore: Vec<CheckCode>,
-    /// List of paths, used to exclude files and/or directories from checks.
-    #[arg(long, value_delimiter = ',')]
-    exclude: Vec<String>,
-    /// Like --exclude, but adds additional files and directories on top of the excluded ones.
-    #[arg(long, value_delimiter = ',')]
-    extend_exclude: Vec<String>,
-    /// List of mappings from file pattern to code to exclude
-    #[arg(long, value_delimiter = ',')]
-    per_file_ignores: Vec<StrCheckCodePair>,
-    /// Output serialization format for error messages.
-    #[arg(long, value_enum, default_value_t=SerializationFormat::Text)]
-    format: SerializationFormat,
-    /// See the files ruff will be run against with the current settings.
-    #[arg(long)]
-    show_files: bool,
-    /// See ruff's settings.
-    #[arg(long)]
-    show_settings: bool,
-    /// Enable automatic additions of noqa directives to failing lines.
-    #[arg(long)]
-    add_noqa: bool,
-    /// Enable automatic formatting.
-    #[arg(long)]
-    autoformat: bool,
-    /// Regular expression matching the name of dummy variables.
-    #[arg(long)]
-    dummy_variable_rgx: Option<Regex>,
-}
-
 #[cfg(feature = "update-informer")]
 fn check_for_updates() {
     use update_informer::{registry, Check};
@@ -121,8 +56,11 @@ fn check_for_updates() {
     }
 }
 
-fn show_settings(settings: RawSettings) {
-    println!("{:#?}", CurrentSettings::from_settings(settings));
+fn show_settings(settings: RawSettings, project_root: Option<PathBuf>, pyproject: Option<PathBuf>) {
+    println!(
+        "{:#?}",
+        CurrentSettings::from_settings(settings, project_root, pyproject)
+    );
 }
 
 fn show_files(files: &[PathBuf], settings: &Settings) {
@@ -288,7 +226,7 @@ fn inner_main() -> Result<ExitCode> {
         .map(|pair| PerFileIgnore::new(pair, &project_root))
         .collect();
 
-    let mut settings = RawSettings::from_pyproject(pyproject, project_root)?;
+    let mut settings = RawSettings::from_pyproject(&pyproject, &project_root)?;
     if !exclude.is_empty() {
         settings.exclude = exclude;
     }
@@ -299,9 +237,25 @@ fn inner_main() -> Result<ExitCode> {
         settings.per_file_ignores = per_file_ignores;
     }
     if !cli.select.is_empty() {
+        warn_on(
+            Warnable::Select,
+            &cli.select,
+            &cli.ignore,
+            &cli.extend_ignore,
+            &settings,
+            &pyproject,
+        );
         settings.select = cli.select;
     }
     if !cli.extend_select.is_empty() {
+        warn_on(
+            Warnable::ExtendSelect,
+            &cli.extend_select,
+            &cli.ignore,
+            &cli.extend_ignore,
+            &settings,
+            &pyproject,
+        );
         settings.extend_select = cli.extend_select;
     }
     if !cli.ignore.is_empty() {
@@ -310,6 +264,9 @@ fn inner_main() -> Result<ExitCode> {
     if !cli.extend_ignore.is_empty() {
         settings.extend_ignore = cli.extend_ignore;
     }
+    if let Some(target_version) = cli.target_version {
+        settings.target_version = target_version;
+    }
     if let Some(dummy_variable_rgx) = cli.dummy_variable_rgx {
         settings.dummy_variable_rgx = dummy_variable_rgx;
     }
@@ -319,7 +276,7 @@ fn inner_main() -> Result<ExitCode> {
         return Ok(ExitCode::FAILURE);
     }
     if cli.show_settings {
-        show_settings(settings);
+        show_settings(settings, project_root, pyproject);
         return Ok(ExitCode::SUCCESS);
     }
 
@@ -403,7 +360,7 @@ fn inner_main() -> Result<ExitCode> {
         #[cfg(feature = "update-informer")]
         check_for_updates();
 
-        if !messages.is_empty() && !cli.exit_zero {
+        if messages.iter().any(|message| !message.fixed) && !cli.exit_zero {
             return Ok(ExitCode::FAILURE);
         }
     }

src/message.rs

@@ -45,7 +45,7 @@ impl fmt::Display for Message {
             ":".cyan(),
             self.location.column(),
             ":".cyan(),
-            self.kind.code().as_str().red().bold(),
+            self.kind.code().as_ref().red().bold(),
             self.kind.body()
         )
     }

src/noqa.rs

@@ -104,9 +104,7 @@ fn add_noqa_inner(
             .unwrap_or(lineno);
 
         if !codes.is_empty() {
-            let matches = matches_by_line
-                .entry(noqa_lineno)
-                .or_insert_with(BTreeSet::new);
+            let matches = matches_by_line.entry(noqa_lineno).or_default();
             matches.append(&mut codes);
         }
     }
@@ -127,7 +125,7 @@ fn add_noqa_inner(
                     Directive::All(start, _) => output.push_str(&line[..start]),
                     Directive::Codes(start, _, _) => output.push_str(&line[..start]),
                 };
-                let codes: Vec<&str> = codes.iter().map(|code| code.as_str()).collect();
+                let codes: Vec<&str> = codes.iter().map(|code| code.as_ref()).collect();
                 output.push_str("  # noqa: ");
                 output.push_str(&codes.join(", "));
                 output.push('\n');
@@ -152,12 +150,12 @@ pub fn add_noqa(
 
 #[cfg(test)]
 mod tests {
-    use crate::ast::types::Range;
     use anyhow::Result;
     use rustpython_parser::ast::Location;
     use rustpython_parser::lexer;
     use rustpython_parser::lexer::LexResult;
 
+    use crate::ast::types::Range;
     use crate::checks::{Check, CheckKind};
     use crate::noqa::{add_noqa_inner, extract_noqa_line_for};
 

src/plugins.rs

@@ -0,0 +1,25 @@
+pub use assert_equals::assert_equals;
+pub use assert_tuple::assert_tuple;
+pub use if_tuple::if_tuple;
+pub use invalid_print_syntax::invalid_print_syntax;
+pub use print_call::print_call;
+pub use super_call_with_parameters::super_call_with_parameters;
+pub use type_of_primitive::type_of_primitive;
+pub use unnecessary_abspath::unnecessary_abspath;
+pub use use_pep585_annotation::use_pep585_annotation;
+pub use use_pep604_annotation::use_pep604_annotation;
+pub use useless_metaclass_type::useless_metaclass_type;
+pub use useless_object_inheritance::useless_object_inheritance;
+
+mod assert_equals;
+mod assert_tuple;
+mod if_tuple;
+mod invalid_print_syntax;
+mod print_call;
+mod super_call_with_parameters;
+mod type_of_primitive;
+mod unnecessary_abspath;
+mod use_pep585_annotation;
+mod use_pep604_annotation;
+mod useless_metaclass_type;
+mod useless_object_inheritance;

src/plugins/assert_equals.rs

@@ -0,0 +1,23 @@
+use rustpython_ast::{Expr, Location};
+
+use crate::ast::checks;
+use crate::autofix::fixer;
+use crate::check_ast::Checker;
+use crate::checks::Fix;
+
+pub fn assert_equals(checker: &mut Checker, expr: &Expr) {
+    if let Some(mut check) = checks::check_assert_equals(expr) {
+        if matches!(checker.autofix, fixer::Mode::Generate | fixer::Mode::Apply) {
+            check.amend(Fix {
+                content: "assertEqual".to_string(),
+                location: Location::new(expr.location.row(), expr.location.column() + 1),
+                end_location: Location::new(
+                    expr.location.row(),
+                    expr.location.column() + 1 + "assertEquals".len(),
+                ),
+                applied: false,
+            });
+        }
+        checker.add_check(check);
+    }
+}

src/plugins/assert_tuple.rs

@@ -0,0 +1,13 @@
+use rustpython_ast::{Expr, Stmt};
+
+use crate::ast::checks;
+use crate::ast::types::{CheckLocator, Range};
+use crate::check_ast::Checker;
+
+pub fn assert_tuple(checker: &mut Checker, stmt: &Stmt, test: &Expr) {
+    if let Some(check) =
+        checks::check_assert_tuple(test, checker.locate_check(Range::from_located(stmt)))
+    {
+        checker.add_check(check);
+    }
+}

src/plugins/if_tuple.rs

@@ -0,0 +1,13 @@
+use rustpython_ast::{Expr, Stmt};
+
+use crate::ast::checks;
+use crate::ast::types::{CheckLocator, Range};
+use crate::check_ast::Checker;
+
+pub fn if_tuple(checker: &mut Checker, stmt: &Stmt, test: &Expr) {
+    if let Some(check) =
+        checks::check_if_tuple(test, checker.locate_check(Range::from_located(stmt)))
+    {
+        checker.add_check(check);
+    }
+}

src/plugins/invalid_print_syntax.rs

@@ -0,0 +1,23 @@
+use rustpython_ast::{Expr, ExprKind};
+
+use crate::ast::types::{Binding, BindingKind, Range};
+use crate::check_ast::Checker;
+use crate::checks::{Check, CheckKind};
+
+pub fn invalid_print_syntax(checker: &mut Checker, left: &Expr) {
+    if let ExprKind::Name { id, .. } = &left.node {
+        if id == "print" {
+            let scope = checker.current_scope();
+            if let Some(Binding {
+                kind: BindingKind::Builtin,
+                ..
+            }) = scope.values.get("print")
+            {
+                checker.add_check(Check::new(
+                    CheckKind::InvalidPrintSyntax,
+                    Range::from_located(left),
+                ));
+            }
+        }
+    }
+}

src/plugins/print_call.rs

@@ -0,0 +1,46 @@
+use log::error;
+use rustpython_ast::{Expr, Stmt, StmtKind};
+
+use crate::ast::checks;
+use crate::autofix::{fixer, fixes};
+use crate::check_ast::Checker;
+use crate::checks::CheckCode;
+
+pub fn print_call(checker: &mut Checker, expr: &Expr, func: &Expr) {
+    if let Some(mut check) = checks::check_print_call(
+        expr,
+        func,
+        checker.settings.enabled.contains(&CheckCode::T201),
+        checker.settings.enabled.contains(&CheckCode::T203),
+    ) {
+        if matches!(checker.autofix, fixer::Mode::Generate | fixer::Mode::Apply) {
+            let context = checker.binding_context();
+            if matches!(
+                checker.parents[context.defined_by].node,
+                StmtKind::Expr { .. }
+            ) {
+                let deleted: Vec<&Stmt> = checker
+                    .deletions
+                    .iter()
+                    .map(|index| checker.parents[*index])
+                    .collect();
+
+                match fixes::remove_stmt(
+                    checker.parents[context.defined_by],
+                    context.defined_in.map(|index| checker.parents[index]),
+                    &deleted,
+                ) {
+                    Ok(fix) => {
+                        if fix.content.is_empty() || fix.content == "pass" {
+                            checker.deletions.insert(context.defined_by);
+                        }
+                        check.amend(fix)
+                    }
+                    Err(e) => error!("Failed to fix unused imports: {}", e),
+                }
+            }
+        }
+
+        checker.add_check(check);
+    }
+}

src/plugins/super_call_with_parameters.rs

@@ -0,0 +1,31 @@
+use rustpython_ast::{Expr, Stmt};
+
+use crate::ast::checks;
+use crate::autofix::{fixer, fixes};
+use crate::check_ast::Checker;
+
+pub fn super_call_with_parameters(
+    checker: &mut Checker,
+    expr: &Expr,
+    func: &Expr,
+    args: &Vec<Expr>,
+) {
+    // Only bother going through the super check at all if we're in a `super` call.
+    // (We check this in `check_super_args` too, so this is just an optimization.)
+    if checks::is_super_call_with_arguments(func, args) {
+        let scope = checker.current_scope();
+        let parents: Vec<&Stmt> = checker
+            .parent_stack
+            .iter()
+            .map(|index| checker.parents[*index])
+            .collect();
+        if let Some(mut check) = checks::check_super_args(scope, &parents, expr, func, args) {
+            if matches!(checker.autofix, fixer::Mode::Generate | fixer::Mode::Apply) {
+                if let Some(fix) = fixes::remove_super_arguments(&mut checker.locator, expr) {
+                    check.amend(fix);
+                }
+            }
+            checker.add_check(check)
+        }
+    }
+}

src/plugins/type_of_primitive.rs

@@ -0,0 +1,25 @@
+use rustpython_ast::Expr;
+
+use crate::ast::checks;
+use crate::ast::types::{CheckLocator, Range};
+use crate::autofix::fixer;
+use crate::check_ast::Checker;
+use crate::checks::{CheckKind, Fix};
+
+pub fn type_of_primitive(checker: &mut Checker, expr: &Expr, func: &Expr, args: &Vec<Expr>) {
+    if let Some(mut check) =
+        checks::check_type_of_primitive(func, args, checker.locate_check(Range::from_located(expr)))
+    {
+        if matches!(checker.autofix, fixer::Mode::Generate | fixer::Mode::Apply) {
+            if let CheckKind::TypeOfPrimitive(primitive) = &check.kind {
+                check.amend(Fix {
+                    content: primitive.builtin(),
+                    location: expr.location,
+                    end_location: expr.end_location,
+                    applied: false,
+                });
+            }
+        }
+        checker.add_check(check);
+    }
+}

src/plugins/unnecessary_abspath.rs

@@ -0,0 +1,25 @@
+use rustpython_ast::Expr;
+
+use crate::ast::checks;
+use crate::ast::types::{CheckLocator, Range};
+use crate::autofix::fixer;
+use crate::check_ast::Checker;
+use crate::checks::Fix;
+
+pub fn unnecessary_abspath(checker: &mut Checker, expr: &Expr, func: &Expr, args: &Vec<Expr>) {
+    if let Some(mut check) = checks::check_unnecessary_abspath(
+        func,
+        args,
+        checker.locate_check(Range::from_located(expr)),
+    ) {
+        if matches!(checker.autofix, fixer::Mode::Generate | fixer::Mode::Apply) {
+            check.amend(Fix {
+                content: "__file__".to_string(),
+                location: expr.location,
+                end_location: expr.end_location,
+                applied: false,
+            });
+        }
+        checker.add_check(check);
+    }
+}

src/plugins/use_pep585_annotation.rs

@@ -0,0 +1,26 @@
+use rustpython_ast::Expr;
+
+use crate::ast::types::Range;
+use crate::autofix::fixer;
+use crate::check_ast::Checker;
+use crate::checks::{Check, CheckKind, Fix};
+use crate::python::typing;
+
+pub fn use_pep585_annotation(checker: &mut Checker, expr: &Expr, id: &str) {
+    // TODO(charlie): Verify that the builtin is imported from the `typing` module.
+    if typing::is_pep585_builtin(id) {
+        let mut check = Check::new(
+            CheckKind::UsePEP585Annotation(id.to_string()),
+            Range::from_located(expr),
+        );
+        if matches!(checker.autofix, fixer::Mode::Generate | fixer::Mode::Apply) {
+            check.amend(Fix {
+                content: id.to_lowercase(),
+                location: expr.location,
+                end_location: expr.end_location,
+                applied: false,
+            })
+        }
+        checker.add_check(check);
+    }
+}

src/plugins/use_pep604_annotation.rs

@@ -0,0 +1,100 @@
+use rustpython_ast::{Constant, Expr, ExprKind, Operator};
+
+use crate::ast::helpers::match_name_or_attr;
+use crate::ast::types::Range;
+use crate::autofix::fixer;
+use crate::check_ast::Checker;
+use crate::checks::{Check, CheckKind, Fix};
+use crate::code_gen::SourceGenerator;
+
+fn optional(expr: &Expr) -> Expr {
+    Expr::new(
+        Default::default(),
+        Default::default(),
+        ExprKind::BinOp {
+            left: Box::new(expr.clone()),
+            op: Operator::BitOr,
+            right: Box::new(Expr::new(
+                Default::default(),
+                Default::default(),
+                ExprKind::Constant {
+                    value: Constant::None,
+                    kind: None,
+                },
+            )),
+        },
+    )
+}
+
+fn union(elts: &[Expr]) -> Expr {
+    if elts.len() == 1 {
+        elts[0].clone()
+    } else {
+        Expr::new(
+            Default::default(),
+            Default::default(),
+            ExprKind::BinOp {
+                left: Box::new(union(&elts[..elts.len() - 1])),
+                op: Operator::BitOr,
+                right: Box::new(elts[elts.len() - 1].clone()),
+            },
+        )
+    }
+}
+
+pub fn use_pep604_annotation(checker: &mut Checker, expr: &Expr, value: &Expr, slice: &Expr) {
+    if match_name_or_attr(value, "Optional") {
+        let mut check = Check::new(CheckKind::UsePEP604Annotation, Range::from_located(expr));
+        if matches!(checker.autofix, fixer::Mode::Generate | fixer::Mode::Apply) {
+            let mut generator = SourceGenerator::new();
+            if let Ok(()) = generator.unparse_expr(&optional(slice), 0) {
+                if let Ok(content) = generator.generate() {
+                    check.amend(Fix {
+                        content,
+                        location: expr.location,
+                        end_location: expr.end_location,
+                        applied: false,
+                    })
+                }
+            }
+        }
+        checker.add_check(check);
+    } else if match_name_or_attr(value, "Union") {
+        let mut check = Check::new(CheckKind::UsePEP604Annotation, Range::from_located(expr));
+        if matches!(checker.autofix, fixer::Mode::Generate | fixer::Mode::Apply) {
+            match &slice.node {
+                ExprKind::Slice { .. } => {
+                    // Invalid type annotation.
+                }
+                ExprKind::Tuple { elts, .. } => {
+                    let mut generator = SourceGenerator::new();
+                    if let Ok(()) = generator.unparse_expr(&union(elts), 0) {
+                        if let Ok(content) = generator.generate() {
+                            check.amend(Fix {
+                                content,
+                                location: expr.location,
+                                end_location: expr.end_location,
+                                applied: false,
+                            })
+                        }
+                    }
+                }
+                _ => {
+                    // Single argument.
+                    let mut generator = SourceGenerator::new();
+                    if let Ok(()) = generator.unparse_expr(slice, 0) {
+                        if let Ok(content) = generator.generate() {
+                            check.amend(Fix {
+                                content,
+                                location: expr.location,
+                                end_location: expr.end_location,
+                                applied: false,
+                            });
+                        }
+                    }
+                }
+            }
+        }
+        checker.add_check(check);
+    }
+}

src/plugins/useless_metaclass_type.rs

@@ -0,0 +1,44 @@
+use log::error;
+use rustpython_ast::{Expr, Stmt};
+
+use crate::ast::checks;
+use crate::ast::types::{CheckLocator, Range};
+use crate::autofix::{fixer, fixes};
+use crate::check_ast::Checker;
+
+pub fn useless_metaclass_type(
+    checker: &mut Checker,
+    stmt: &Stmt,
+    value: &Expr,
+    targets: &Vec<Expr>,
+) {
+    if let Some(mut check) = checks::check_useless_metaclass_type(
+        targets,
+        value,
+        checker.locate_check(Range::from_located(stmt)),
+    ) {
+        if matches!(checker.autofix, fixer::Mode::Generate | fixer::Mode::Apply) {
+            let context = checker.binding_context();
+            let deleted: Vec<&Stmt> = checker
+                .deletions
+                .iter()
+                .map(|index| checker.parents[*index])
+                .collect();
+
+            match fixes::remove_stmt(
+                checker.parents[context.defined_by],
+                context.defined_in.map(|index| checker.parents[index]),
+                &deleted,
+            ) {
+                Ok(fix) => {
+                    if fix.content.is_empty() || fix.content == "pass" {
+                        checker.deletions.insert(context.defined_by);
+                    }
+                    check.amend(fix)
+                }
+                Err(e) => error!("Failed to fix unused imports: {}", e),
+            }
+        }
+        checker.add_check(check);
+    }
+}

src/plugins/useless_object_inheritance.rs

@@ -0,0 +1,29 @@
+use rustpython_ast::{Expr, Keyword, Stmt};
+
+use crate::ast::checks;
+use crate::autofix::{fixer, fixes};
+use crate::check_ast::Checker;
+
+pub fn useless_object_inheritance(
+    checker: &mut Checker,
+    stmt: &Stmt,
+    name: &str,
+    bases: &[Expr],
+    keywords: &[Keyword],
+) {
+    let scope = checker.current_scope();
+    if let Some(mut check) = checks::check_useless_object_inheritance(name, bases, scope) {
+        if matches!(checker.autofix, fixer::Mode::Generate | fixer::Mode::Apply) {
+            if let Some(fix) = fixes::remove_class_def_base(
+                &mut checker.locator,
+                &stmt.location,
+                check.location,
+                bases,
+                keywords,
+            ) {
+                check.amend(fix);
+            }
+        }
+        checker.add_check(check);
+    }
+}

src/pyproject.rs

@@ -9,6 +9,7 @@ use serde::{Deserialize, Deserializer};
 
 use crate::checks::CheckCode;
 use crate::fs;
+use crate::settings::PythonVersion;
 
 pub fn load_config(pyproject: &Option<PathBuf>) -> Result<Config> {
     match pyproject {
@@ -41,6 +42,7 @@ pub struct Config {
     #[serde(default)]
     pub per_file_ignores: Vec<StrCheckCodePair>,
     pub dummy_variable_rgx: Option<String>,
+    pub target_version: Option<PythonVersion>,
 }
 
 #[derive(Clone, Debug, PartialEq, Eq)]
@@ -152,12 +154,13 @@ mod tests {
 
     use anyhow::Result;
 
-    use super::StrCheckCodePair;
     use crate::checks::CheckCode;
     use crate::pyproject::{
         find_project_root, find_pyproject_toml, parse_pyproject_toml, Config, PyProject, Tools,
     };
 
+    use super::StrCheckCodePair;
+
     #[test]
     fn deserialize() -> Result<()> {
         let pyproject: PyProject = toml::from_str(r#""#)?;
@@ -189,6 +192,7 @@ mod tests {
                     extend_ignore: vec![],
                     per_file_ignores: vec![],
                     dummy_variable_rgx: None,
+                    target_version: None,
                 })
             })
         );
@@ -213,6 +217,7 @@ line-length = 79
                     extend_ignore: vec![],
                     per_file_ignores: vec![],
                     dummy_variable_rgx: None,
+                    target_version: None,
                 })
             })
         );
@@ -237,6 +242,7 @@ exclude = ["foo.py"]
                     extend_ignore: vec![],
                     per_file_ignores: vec![],
                     dummy_variable_rgx: None,
+                    target_version: None,
                 })
             })
         );
@@ -261,6 +267,7 @@ select = ["E501"]
                     extend_ignore: vec![],
                     per_file_ignores: vec![],
                     dummy_variable_rgx: None,
+                    target_version: None,
                 })
             })
         );
@@ -286,6 +293,7 @@ ignore = ["E501"]
                     extend_ignore: vec![],
                     per_file_ignores: vec![],
                     dummy_variable_rgx: None,
+                    target_version: None,
                 })
             })
         );
@@ -354,6 +362,7 @@ other-attribute = 1
                 extend_ignore: vec![],
                 per_file_ignores: vec![],
                 dummy_variable_rgx: None,
+                target_version: None,
             }
         );
 

src/python/typing.rs

@@ -7,6 +7,7 @@ static ANNOTATED_SUBSCRIPTS: Lazy<BTreeSet<&'static str>> = Lazy::new(|| {
         "AbstractAsyncContextManager",
         "AbstractContextManager",
         "AbstractSet",
+        // "Annotated",
         "AsyncContextManager",
         "AsyncGenerator",
         "AsyncIterable",
@@ -87,3 +88,14 @@ static ANNOTATED_SUBSCRIPTS: Lazy<BTreeSet<&'static str>> = Lazy::new(|| {
 pub fn is_annotated_subscript(name: &str) -> bool {
     ANNOTATED_SUBSCRIPTS.contains(name)
 }
+
+pub fn is_pep593_annotated_subscript(name: &str) -> bool {
+    name == "Annotated"
+}
+
+static PEP_585_BUILTINS: Lazy<BTreeSet<&'static str>> =
+    Lazy::new(|| BTreeSet::from(["Dict", "FrozenSet", "List", "Set", "Tuple", "Type"]));
+
+pub fn is_pep585_builtin(name: &str) -> bool {
+    PEP_585_BUILTINS.contains(name)
+}

src/settings.rs

@@ -1,16 +1,50 @@
 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 crate::checks::{CheckCode, DEFAULT_CHECK_CODES};
 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),
@@ -60,9 +94,8 @@ pub struct RawSettings {
     pub ignore: Vec<CheckCode>,
     pub line_length: usize,
     pub per_file_ignores: Vec<PerFileIgnore>,
-    pub project_root: Option<PathBuf>,
-    pub pyproject: Option<PathBuf>,
     pub select: Vec<CheckCode>,
+    pub target_version: PythonVersion,
 }
 
 static DEFAULT_EXCLUDE: Lazy<Vec<FilePattern>> = Lazy::new(|| {
@@ -94,44 +127,43 @@ static DEFAULT_DUMMY_VARIABLE_RGX: Lazy<Regex> =
 
 impl RawSettings {
     pub fn from_pyproject(
-        pyproject: Option<PathBuf>,
-        project_root: Option<PathBuf>,
+        pyproject: &Option<PathBuf>,
+        project_root: &Option<PathBuf>,
     ) -> Result<Self> {
-        let config = load_config(&pyproject)?;
+        let config = load_config(pyproject)?;
         Ok(RawSettings {
             dummy_variable_rgx: match config.dummy_variable_rgx {
                 Some(pattern) => Regex::new(&pattern)
                     .map_err(|e| anyhow!("Invalid dummy-variable-rgx value: {e}"))?,
                 None => DEFAULT_DUMMY_VARIABLE_RGX.clone(),
             },
+            target_version: config.target_version.unwrap_or(PythonVersion::Py310),
             exclude: config
                 .exclude
                 .map(|paths| {
                     paths
                         .iter()
-                        .map(|path| FilePattern::from_user(path, &project_root))
+                        .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))
+                .map(|path| FilePattern::from_user(path, project_root))
                 .collect(),
             extend_ignore: config.extend_ignore,
+            select: config
+                .select
+                .unwrap_or_else(|| DEFAULT_CHECK_CODES.to_vec()),
             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))
+                .map(|pair| PerFileIgnore::new(pair, project_root))
                 .collect(),
-            project_root,
-            pyproject,
-            select: config
-                .select
-                .unwrap_or_else(|| DEFAULT_CHECK_CODES.to_vec()),
         })
     }
 }
@@ -144,6 +176,7 @@ pub struct Settings {
     pub extend_exclude: Vec<FilePattern>,
     pub line_length: usize,
     pub per_file_ignores: Vec<PerFileIgnore>,
+    pub target_version: PythonVersion,
 }
 
 impl Settings {
@@ -165,6 +198,7 @@ impl Settings {
             extend_exclude: settings.extend_exclude,
             line_length: settings.line_length,
             per_file_ignores: settings.per_file_ignores,
+            target_version: PythonVersion::Py310,
         }
     }
 
@@ -176,6 +210,7 @@ impl Settings {
             extend_exclude: vec![],
             line_length: 88,
             per_file_ignores: vec![],
+            target_version: PythonVersion::Py310,
         }
     }
 
@@ -187,6 +222,7 @@ impl Settings {
             extend_exclude: vec![],
             line_length: 88,
             per_file_ignores: vec![],
+            target_version: PythonVersion::Py310,
         }
     }
 }
@@ -238,13 +274,18 @@ pub struct CurrentSettings {
     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>,
-    pub select: Vec<CheckCode>,
 }
 
 impl CurrentSettings {
-    pub fn from_settings(settings: RawSettings) -> Self {
+    pub fn from_settings(
+        settings: RawSettings,
+        project_root: Option<PathBuf>,
+        pyproject: Option<PathBuf>,
+    ) -> Self {
         Self {
             dummy_variable_rgx: settings.dummy_variable_rgx,
             exclude: settings
@@ -262,9 +303,10 @@ impl CurrentSettings {
             ignore: settings.ignore,
             line_length: settings.line_length,
             per_file_ignores: settings.per_file_ignores,
-            project_root: settings.project_root,
-            pyproject: settings.pyproject,
             select: settings.select,
+            target_version: settings.target_version,
+            project_root,
+            pyproject,
         }
     }
 }

src/snapshots/ruff__linter__tests__c400.snap

@@ -0,0 +1,13 @@
+---
+source: src/linter.rs
+expression: checks
+---
+- kind: UnnecessaryGeneratorList
+  location:
+    row: 1
+    column: 5
+  end_location:
+    row: 1
+    column: 30
+  fix: ~
+

src/snapshots/ruff__linter__tests__c401.snap

@@ -0,0 +1,13 @@
+---
+source: src/linter.rs
+expression: checks
+---
+- kind: UnnecessaryGeneratorList
+  location:
+    row: 1
+    column: 5
+  end_location:
+    row: 1
+    column: 29
+  fix: ~
+

src/snapshots/ruff__linter__tests__c402.snap

@@ -0,0 +1,13 @@
+---
+source: src/linter.rs
+expression: checks
+---
+- kind: UnnecessaryListComprehensionDict
+  location:
+    row: 1
+    column: 5
+  end_location:
+    row: 1
+    column: 35
+  fix: ~
+

src/snapshots/ruff__linter__tests__c403.snap

@@ -0,0 +1,13 @@
+---
+source: src/linter.rs
+expression: checks
+---
+- kind: UnnecessaryListComprehensionSet
+  location:
+    row: 1
+    column: 5
+  end_location:
+    row: 1
+    column: 31
+  fix: ~
+

src/snapshots/ruff__linter__tests__c404.snap

@@ -0,0 +1,13 @@
+---
+source: src/linter.rs
+expression: checks
+---
+- kind: UnnecessaryListComprehensionDict
+  location:
+    row: 1
+    column: 5
+  end_location:
+    row: 1
+    column: 37
+  fix: ~
+

src/snapshots/ruff__linter__tests__c405.snap

@@ -0,0 +1,41 @@
+---
+source: src/linter.rs
+expression: checks
+---
+- kind:
+    UnnecessaryLiteralSet: list
+  location:
+    row: 1
+    column: 6
+  end_location:
+    row: 1
+    column: 17
+  fix: ~
+- kind:
+    UnnecessaryLiteralSet: tuple
+  location:
+    row: 2
+    column: 6
+  end_location:
+    row: 2
+    column: 17
+  fix: ~
+- kind:
+    UnnecessaryLiteralSet: list
+  location:
+    row: 3
+    column: 6
+  end_location:
+    row: 3
+    column: 13
+  fix: ~
+- kind:
+    UnnecessaryLiteralSet: tuple
+  location:
+    row: 4
+    column: 6
+  end_location:
+    row: 4
+    column: 13
+  fix: ~
+

src/snapshots/ruff__linter__tests__c406.snap

@@ -0,0 +1,41 @@
+---
+source: src/linter.rs
+expression: checks
+---
+- kind:
+    UnnecessaryLiteralDict: list
+  location:
+    row: 1
+    column: 6
+  end_location:
+    row: 1
+    column: 20
+  fix: ~
+- kind:
+    UnnecessaryLiteralDict: tuple
+  location:
+    row: 2
+    column: 6
+  end_location:
+    row: 2
+    column: 21
+  fix: ~
+- kind:
+    UnnecessaryLiteralDict: list
+  location:
+    row: 3
+    column: 6
+  end_location:
+    row: 3
+    column: 14
+  fix: ~
+- kind:
+    UnnecessaryLiteralDict: tuple
+  location:
+    row: 4
+    column: 6
+  end_location:
+    row: 4
+    column: 14
+  fix: ~
+

src/snapshots/ruff__linter__tests__c408.snap

@@ -0,0 +1,41 @@
+---
+source: src/linter.rs
+expression: checks
+---
+- kind:
+    UnnecessaryCollectionCall: tuple
+  location:
+    row: 1
+    column: 5
+  end_location:
+    row: 1
+    column: 12
+  fix: ~
+- kind:
+    UnnecessaryCollectionCall: list
+  location:
+    row: 2
+    column: 5
+  end_location:
+    row: 2
+    column: 11
+  fix: ~
+- kind:
+    UnnecessaryCollectionCall: dict
+  location:
+    row: 3
+    column: 6
+  end_location:
+    row: 3
+    column: 12
+  fix: ~
+- kind:
+    UnnecessaryCollectionCall: dict
+  location:
+    row: 4
+    column: 6
+  end_location:
+    row: 4
+    column: 15
+  fix: ~
+

src/snapshots/ruff__linter__tests__c415.snap

@@ -0,0 +1,41 @@
+---
+source: src/linter.rs
+expression: checks
+---
+- kind:
+    UnnecessarySubscriptReversal: set
+  location:
+    row: 2
+    column: 5
+  end_location:
+    row: 2
+    column: 19
+  fix: ~
+- kind:
+    UnnecessarySubscriptReversal: reversed
+  location:
+    row: 3
+    column: 5
+  end_location:
+    row: 3
+    column: 24
+  fix: ~
+- kind:
+    UnnecessarySubscriptReversal: sorted
+  location:
+    row: 4
+    column: 5
+  end_location:
+    row: 4
+    column: 22
+  fix: ~
+- kind:
+    UnnecessarySubscriptReversal: sorted
+  location:
+    row: 5
+    column: 5
+  end_location:
+    row: 5
+    column: 36
+  fix: ~
+

src/snapshots/ruff__linter__tests__f401.snap

@@ -3,7 +3,8 @@ source: src/linter.rs
 expression: checks
 ---
 - kind:
-    UnusedImport: functools
+    UnusedImport:
+      - functools
   location:
     row: 2
     column: 1
@@ -20,7 +21,8 @@ expression: checks
       column: 21
     applied: false
 - kind:
-    UnusedImport: collections.OrderedDict
+    UnusedImport:
+      - collections.OrderedDict
   location:
     row: 4
     column: 1
@@ -37,7 +39,8 @@ expression: checks
       column: 2
     applied: false
 - kind:
-    UnusedImport: logging.handlers
+    UnusedImport:
+      - logging.handlers
   location:
     row: 12
     column: 1
@@ -54,7 +57,8 @@ expression: checks
       column: 24
     applied: false
 - kind:
-    UnusedImport: shelve
+    UnusedImport:
+      - shelve
   location:
     row: 33
     column: 5
@@ -71,7 +75,8 @@ expression: checks
       column: 1
     applied: false
 - kind:
-    UnusedImport: importlib
+    UnusedImport:
+      - importlib
   location:
     row: 34
     column: 5
@@ -79,16 +84,17 @@ expression: checks
     row: 34
     column: 21
   fix:
-    content: pass
+    content: ""
     location:
       row: 34
-      column: 5
+      column: 1
     end_location:
-      row: 34
-      column: 21
+      row: 35
+      column: 1
     applied: false
 - kind:
-    UnusedImport: pathlib
+    UnusedImport:
+      - pathlib
   location:
     row: 38
     column: 5
@@ -105,7 +111,8 @@ expression: checks
       column: 1
     applied: false
 - kind:
-    UnusedImport: pickle
+    UnusedImport:
+      - pickle
   location:
     row: 53
     column: 9

src/snapshots/ruff__linter__tests__f722.snap

@@ -9,6 +9,6 @@ expression: checks
     column: 13
   end_location:
     row: 9
-    column: 17
+    column: 16
   fix: ~
 

src/snapshots/ruff__linter__tests__f821.snap

@@ -45,7 +45,7 @@ expression: checks
     column: 5
   end_location:
     row: 58
-    column: 9
+    column: 8
   fix: ~
 - kind:
     UndefinedName: TOMATO
@@ -74,4 +74,31 @@ expression: checks
     row: 89
     column: 9
   fix: ~
+- kind:
+    UndefinedName: PEP593Test123
+  location:
+    row: 114
+    column: 10
+  end_location:
+    row: 114
+    column: 23
+  fix: ~
+- kind:
+    UndefinedName: foo
+  location:
+    row: 122
+    column: 15
+  end_location:
+    row: 122
+    column: 18
+  fix: ~
+- kind:
+    UndefinedName: bar
+  location:
+    row: 122
+    column: 22
+  end_location:
+    row: 122
+    column: 25
+  fix: ~
 

src/snapshots/ruff__linter__tests__future_annotations.snap

@@ -3,7 +3,8 @@ source: src/linter.rs
 expression: checks
 ---
 - kind:
-    UnusedImport: models.Nut
+    UnusedImport:
+      - models.Nut
   location:
     row: 5
     column: 1

src/snapshots/ruff__linter__tests__u002.snap

@@ -0,0 +1,53 @@
+---
+source: src/linter.rs
+expression: checks
+---
+- kind: UnnecessaryAbspath
+  location:
+    row: 3
+    column: 5
+  end_location:
+    row: 3
+    column: 22
+  fix:
+    content: __file__
+    location:
+      row: 3
+      column: 5
+    end_location:
+      row: 3
+      column: 22
+    applied: false
+- kind: UnnecessaryAbspath
+  location:
+    row: 9
+    column: 5
+  end_location:
+    row: 9
+    column: 30
+  fix:
+    content: __file__
+    location:
+      row: 9
+      column: 5
+    end_location:
+      row: 9
+      column: 30
+    applied: false
+- kind: UnnecessaryAbspath
+  location:
+    row: 15
+    column: 5
+  end_location:
+    row: 15
+    column: 27
+  fix:
+    content: __file__
+    location:
+      row: 15
+      column: 5
+    end_location:
+      row: 15
+      column: 27
+    applied: false
+

src/snapshots/ruff__linter__tests__u003.snap

@@ -0,0 +1,90 @@
+---
+source: src/linter.rs
+expression: checks
+---
+- kind:
+    TypeOfPrimitive: Str
+  location:
+    row: 1
+    column: 1
+  end_location:
+    row: 1
+    column: 9
+  fix:
+    content: str
+    location:
+      row: 1
+      column: 1
+    end_location:
+      row: 1
+      column: 9
+    applied: false
+- kind:
+    TypeOfPrimitive: Bytes
+  location:
+    row: 2
+    column: 1
+  end_location:
+    row: 2
+    column: 10
+  fix:
+    content: bytes
+    location:
+      row: 2
+      column: 1
+    end_location:
+      row: 2
+      column: 10
+    applied: false
+- kind:
+    TypeOfPrimitive: Int
+  location:
+    row: 3
+    column: 1
+  end_location:
+    row: 3
+    column: 8
+  fix:
+    content: int
+    location:
+      row: 3
+      column: 1
+    end_location:
+      row: 3
+      column: 8
+    applied: false
+- kind:
+    TypeOfPrimitive: Float
+  location:
+    row: 4
+    column: 1
+  end_location:
+    row: 4
+    column: 9
+  fix:
+    content: float
+    location:
+      row: 4
+      column: 1
+    end_location:
+      row: 4
+      column: 9
+    applied: false
+- kind:
+    TypeOfPrimitive: Complex
+  location:
+    row: 5
+    column: 1
+  end_location:
+    row: 5
+    column: 9
+  fix:
+    content: complex
+    location:
+      row: 5
+      column: 1
+    end_location:
+      row: 5
+      column: 9
+    applied: false
+

src/snapshots/ruff__linter__tests__u006.snap

@@ -0,0 +1,39 @@
+---
+source: src/linter.rs
+expression: checks
+---
+- kind:
+    UsePEP585Annotation: List
+  location:
+    row: 4
+    column: 10
+  end_location:
+    row: 4
+    column: 14
+  fix:
+    content: list
+    location:
+      row: 4
+      column: 10
+    end_location:
+      row: 4
+      column: 14
+    applied: false
+- kind:
+    UsePEP585Annotation: List
+  location:
+    row: 11
+    column: 10
+  end_location:
+    row: 11
+    column: 21
+  fix:
+    content: list
+    location:
+      row: 11
+      column: 10
+    end_location:
+      row: 11
+      column: 21
+    applied: false
+

src/snapshots/ruff__linter__tests__u007.snap

@@ -0,0 +1,133 @@
+---
+source: src/linter.rs
+expression: checks
+---
+- kind: UsePEP604Annotation
+  location:
+    row: 4
+    column: 10
+  end_location:
+    row: 4
+    column: 23
+  fix:
+    content: str | None
+    location:
+      row: 4
+      column: 10
+    end_location:
+      row: 4
+      column: 23
+    applied: false
+- kind: UsePEP604Annotation
+  location:
+    row: 11
+    column: 10
+  end_location:
+    row: 11
+    column: 30
+  fix:
+    content: str | None
+    location:
+      row: 11
+      column: 10
+    end_location:
+      row: 11
+      column: 30
+    applied: false
+- kind: UsePEP604Annotation
+  location:
+    row: 18
+    column: 10
+  end_location:
+    row: 18
+    column: 46
+  fix:
+    content: "str | int | Union[float, bytes]"
+    location:
+      row: 18
+      column: 10
+    end_location:
+      row: 18
+      column: 46
+    applied: false
+- kind: UsePEP604Annotation
+  location:
+    row: 18
+    column: 26
+  end_location:
+    row: 18
+    column: 45
+  fix:
+    content: float | bytes
+    location:
+      row: 18
+      column: 26
+    end_location:
+      row: 18
+      column: 45
+    applied: false
+- kind: UsePEP604Annotation
+  location:
+    row: 25
+    column: 10
+  end_location:
+    row: 25
+    column: 32
+  fix:
+    content: str | int
+    location:
+      row: 25
+      column: 10
+    end_location:
+      row: 25
+      column: 32
+    applied: false
+- kind: UsePEP604Annotation
+  location:
+    row: 32
+    column: 11
+  end_location:
+    row: 32
+    column: 47
+  fix:
+    content: "str | int | Union[float, bytes]"
+    location:
+      row: 32
+      column: 11
+    end_location:
+      row: 32
+      column: 47
+    applied: false
+- kind: UsePEP604Annotation
+  location:
+    row: 32
+    column: 11
+  end_location:
+    row: 32
+    column: 47
+  fix:
+    content: float | bytes
+    location:
+      row: 32
+      column: 11
+    end_location:
+      row: 32
+      column: 47
+    applied: false
+- kind: UsePEP604Annotation
+  location:
+    row: 39
+    column: 11
+  end_location:
+    row: 39
+    column: 33
+  fix:
+    content: str | int
+    location:
+      row: 39
+      column: 11
+    end_location:
+      row: 39
+      column: 33
+    applied: false
+

src/snapshots/ruff__linter__tests__w292.snap

@@ -0,0 +1,13 @@
+---
+source: src/linter.rs
+expression: checks
+---
+- kind: NoNewLineAtEndOfFile
+  location:
+    row: 2
+    column: 9
+  end_location:
+    row: 2
+    column: 9
+  fix: ~
+

src/snapshots/ruff__linter__tests__w292_0.snap

@@ -0,0 +1,13 @@
+---
+source: src/linter.rs
+expression: checks
+---
+- kind: NoNewLineAtEndOfFile
+  location:
+    row: 2
+    column: 9
+  end_location:
+    row: 2
+    column: 9
+  fix: ~
+

src/snapshots/ruff__linter__tests__w292_1.snap

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

src/snapshots/ruff__linter__tests__w292_2.snap

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