Bump version to 0.0.219

Improve globset documentation and help message (#1808 )
Closes #1545.
2023-01-11 23:46:01 -05:00 · 2023-01-11 23:41:56 -05:00 · 2023-01-11 23:12:55 -05:00 · 2023-01-11 22:32:14 -05:00 · 2023-01-11 20:01:54 -05:00 · 2023-01-11 19:59:00 -05:00
621 changed files with 25993 additions and 17768 deletions
--- a/.github/ISSUE_TEMPLATE.md
+++ b/.github/ISSUE_TEMPLATE.md
@@ -0,0 +1,10 @@
+<!--
+Thank you for taking the time to report an issue! We're glad to have you involved with Ruff.
+
+If you're filing a bug report, please consider including the following information:
+
+- A minimal code snippet that reproduces the bug.
+- The command you invoked (e.g., `ruff /path/to/file.py --fix`), ideally including the `--isolated` flag.
+- The current Ruff settings (any relevant sections from your `pyproject.toml`).
+- The current Ruff version (`ruff --version`).
+-->
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -26,25 +26,12 @@ jobs:
          profile: minimal
          toolchain: nightly-2022-11-01
          override: true
-          components: rustfmt
-      - uses: actions/cache@v3
-        env:
-          cache-name: cache-cargo
-        with:
-          path: |
-            ~/.cargo/registry
-            ~/.cargo/git
-          key: ${{ runner.os }}-build-${{ env.cache-name }}-${{ hashFiles('**/Cargo.lock') }}
-          restore-keys: |
-            ${{ runner.os }}-build-${{ env.cache-name }}-
-            ${{ runner.os }}-build-
-            ${{ runner.os }}-
-      - run: cargo build --all --release
-      - run: ./target/release/ruff_dev generate-all
+      - uses: Swatinem/rust-cache@v1
+      - run: cargo build --all
+      - run: ./target/debug/ruff_dev generate-all
      - run: git diff --quiet README.md || echo "::error file=README.md::This file is outdated. Run 'cargo +nightly dev generate-all'."
-      - run: git diff --quiet src/registry_gen.rs || echo "::error file=src/registry_gen.rs::This file is outdated. Run 'cargo +nightly dev generate-all'."
      - run: git diff --quiet ruff.schema.json || echo "::error file=ruff.schema.json::This file is outdated. Run 'cargo +nightly dev generate-all'."
-      - run: git diff --exit-code -- README.md src/registry_gen.rs ruff.schema.json
+      - run: git diff --exit-code -- README.md ruff.schema.json

  cargo-fmt:
    name: "cargo fmt"
@@ -57,18 +44,6 @@ jobs:
          toolchain: nightly-2022-11-01
          override: true
          components: rustfmt
-      - uses: actions/cache@v3
-        env:
-          cache-name: cache-cargo
-        with:
-          path: |
-            ~/.cargo/registry
-            ~/.cargo/git
-          key: ${{ runner.os }}-build-${{ env.cache-name }}-${{ hashFiles('**/Cargo.lock') }}
-          restore-keys: |
-            ${{ runner.os }}-build-${{ env.cache-name }}-
-            ${{ runner.os }}-build-
-            ${{ runner.os }}-
      - run: cargo fmt --all --check

  cargo_clippy:
@@ -83,18 +58,7 @@ jobs:
          override: true
          components: clippy
          target: wasm32-unknown-unknown
-      - uses: actions/cache@v3
-        env:
-          cache-name: cache-cargo
-        with:
-          path: |
-            ~/.cargo/registry
-            ~/.cargo/git
-          key: ${{ runner.os }}-build-${{ env.cache-name }}-${{ hashFiles('**/Cargo.lock') }}
-          restore-keys: |
-            ${{ runner.os }}-build-${{ env.cache-name }}-
-            ${{ runner.os }}-build-
-            ${{ runner.os }}-
+      - uses: Swatinem/rust-cache@v1
      - run: cargo clippy --workspace --all-targets --all-features -- -D warnings -W clippy::pedantic
      - run: cargo clippy --workspace --target wasm32-unknown-unknown --all-features -- -D warnings -W clippy::pedantic

@@ -108,18 +72,7 @@ jobs:
          profile: minimal
          toolchain: nightly-2022-11-01
          override: true
-      - uses: actions/cache@v3
-        env:
-          cache-name: cache-cargo
-        with:
-          path: |
-            ~/.cargo/registry
-            ~/.cargo/git
-          key: ${{ runner.os }}-build-${{ env.cache-name }}-${{ hashFiles('**/Cargo.lock') }}
-          restore-keys: |
-            ${{ runner.os }}-build-${{ env.cache-name }}-
-            ${{ runner.os }}-build-
-            ${{ runner.os }}-
+      - uses: Swatinem/rust-cache@v1
      - run: cargo install cargo-insta
      - run: pip install black[d]==22.12.0
      - name: Run tests
@@ -168,22 +121,11 @@ jobs:
          profile: minimal
          toolchain: nightly-2022-11-01
          override: true
+      - uses: Swatinem/rust-cache@v1
      - uses: actions/setup-python@v4
        with:
          python-version: "3.11"
      - run: pip install maturin
-      - uses: actions/cache@v3
-        env:
-          cache-name: cache-cargo
-        with:
-          path: |
-            ~/.cargo/registry
-            ~/.cargo/git
-          key: ${{ runner.os }}-build-${{ env.cache-name }}-${{ hashFiles('**/Cargo.lock') }}
-          restore-keys: |
-            ${{ runner.os }}-build-${{ env.cache-name }}-
-            ${{ runner.os }}-build-
-            ${{ runner.os }}-
      - run: maturin build -b bin

  typos:
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -1,6 +1,6 @@
 repos:
  - repo: https://github.com/charliermarsh/ruff-pre-commit
-    rev: v0.0.211
+    rev: v0.0.219
    hooks:
      - id: ruff

--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -56,33 +56,36 @@ prior to merging.

 There are four phases to adding a new lint rule:

-1. Define the rule in `src/registry.rs`.
-2. Define the _logic_ for triggering the rule in `src/checkers/ast.rs` (for AST-based checks),
+1. Define the violation struct in `src/violations.rs` (e.g., `ModuleImportNotAtTopOfFile`).
+2. Map the violation struct to a rule code in `src/registry.rs` (e.g., `E402`).
+3. Define the logic for triggering the violation in `src/checkers/ast.rs` (for AST-based checks),
   `src/checkers/tokens.rs` (for token-based checks), or `src/checkers/lines.rs` (for text-based checks).
-3. Add a test fixture.
-4. Update the generated files (documentation and generated code).
+4. Add a test fixture.
+5. Update the generated files (documentation and generated code).

-To define the rule, open up `src/registry.rs`. You'll need to define both a `CheckCode` and
-`CheckKind`. As an example, you can grep for `E402` and `ModuleImportNotAtTopOfFile`, and follow the
-pattern implemented therein.
+To define the violation, open up `src/violations.rs`, and define a new struct using the
+`define_violation!` macro. There are plenty of examples in that file, so feel free to pattern-match
+against the existing structs.

-To trigger the rule, you'll likely want to augment the logic in `src/checkers/ast.rs`, which defines
-the Python AST visitor, responsible for iterating over the abstract syntax tree and collecting
-lint-rule violations as it goes. If you need to inspect the AST, you can run
-`cargo +nightly dev print-ast` with a Python file. Grep for the `Check::new` invocations to
-understand how other, similar rules are implemented.
+To trigger the violation, you'll likely want to augment the logic in `src/checkers/ast.rs`, which
+defines the Python AST visitor, responsible for iterating over the abstract syntax tree and
+collecting diagnostics as it goes.

-To add a test fixture, create a file under `resources/test/fixtures/[plugin-name]`, 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.
+If you need to inspect the AST, you can run `cargo +nightly dev print-ast` with a Python file. Grep
+for the `Check::new` invocations to understand how other, similar rules are implemented.
+
+To add a test fixture, create a file under `resources/test/fixtures/[origin]`, named to match
+the code you defined earlier (e.g., `resources/test/fixtures/pycodestyle/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 `cargo +nightly dev generate-all` to generate the code for your new fixture. Then run Ruff
 locally with (e.g.) `cargo run resources/test/fixtures/pycodestyle/E402.py --no-cache --select E402`.

 Once you're satisfied with the output, codify the behavior as a snapshot test by adding a new
-`test_case` macro in the relevant `src/[plugin-name]/mod.rs` file. Then, run `cargo test`. Your
-test will fail, but you'll be prompted to follow-up with `cargo insta review`. Accept the generated
-snapshot, then commit the snapshot file alongside the rest of your changes.
+`test_case` macro in the relevant `src/[origin]/mod.rs` file. Then, run `cargo test --all`.
+Your test will fail, but you'll be prompted to follow-up with `cargo insta review`. Accept the
+generated snapshot, then commit the snapshot file alongside the rest of your changes.

 Finally, regenerate the documentation and generated code with `cargo +nightly dev generate-all`.

--- a/Cargo.lock
+++ b/Cargo.lock
@@ -367,15 +367,6 @@ dependencies = [
 "winapi",
 ]

-[[package]]
-name = "codegen"
-version = "0.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ff61280aed771c3070e7dcc9e050c66f1eb1e3b96431ba66f9f74641d02fc41d"
-dependencies = [
- "indexmap",
-]
-
 [[package]]
 name = "codespan-reporting"
 version = "0.11.1"
@@ -744,10 +735,11 @@ checksum = "0ce7134b9999ecaf8bcd65542e436736ef32ddca1b3e06094cb6ec5755203b80"

 [[package]]
 name = "flake8-to-ruff"
-version = "0.0.211-dev.0"
+version = "0.0.219-dev.0"
 dependencies = [
 "anyhow",
 "clap 4.0.32",
+ "colored",
 "configparser",
 "once_cell",
 "regex",
@@ -757,7 +749,7 @@ dependencies = [
 "serde_json",
 "strum",
 "strum_macros",
- "toml",
+ "toml_edit",
 ]

 [[package]]
@@ -1294,6 +1286,15 @@ dependencies = [
 "version_check",
 ]

+[[package]]
+name = "nom8"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ae01545c9c7fc4486ab7debaf2aad7003ac19431791868fb2e8066df97fad2f8"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "notify"
 version = "5.0.0"
@@ -1365,9 +1366,9 @@ dependencies = [

 [[package]]
 name = "once_cell"
-version = "1.16.0"
+version = "1.17.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "86f0b0d4bf799edbc74508c1e8bf170ff5f41238e5f8225603ca7caaae2b7860"
+checksum = "6f61fba1741ea2b3d6a1e3178721804bb716a68a6aeba1149b5d52e3d464ea66"

 [[package]]
 name = "oorandom"
@@ -1873,7 +1874,7 @@ dependencies = [

 [[package]]
 name = "ruff"
-version = "0.0.211"
+version = "0.0.219"
 dependencies = [
 "annotate-snippets 0.9.1",
 "anyhow",
@@ -1931,7 +1932,7 @@ dependencies = [
 "test-case",
 "textwrap",
 "titlecase",
- "toml",
+ "toml_edit",
 "update-informer",
 "ureq",
 "walkdir",
@@ -1941,11 +1942,10 @@ dependencies = [

 [[package]]
 name = "ruff_dev"
-version = "0.0.211"
+version = "0.0.219"
 dependencies = [
 "anyhow",
 "clap 4.0.32",
- "codegen",
 "itertools",
 "libcst",
 "once_cell",
@@ -1962,8 +1962,9 @@ dependencies = [

 [[package]]
 name = "ruff_macros"
-version = "0.0.211"
+version = "0.0.219"
 dependencies = [
+ "once_cell",
 "proc-macro2",
 "quote",
 "syn",
@@ -2005,7 +2006,7 @@ dependencies = [
 [[package]]
 name = "rustpython-ast"
 version = "0.1.0"
-source = "git+https://github.com/RustPython/RustPython.git?rev=4d53c7cb27c0379adf8b51c4d3d0d2174f41d590#4d53c7cb27c0379adf8b51c4d3d0d2174f41d590"
+source = "git+https://github.com/RustPython/RustPython.git?rev=d532160333ffeb6dbeca2c2728c2391cd1e53b7f#d532160333ffeb6dbeca2c2728c2391cd1e53b7f"
 dependencies = [
 "num-bigint",
 "rustpython-common",
@@ -2015,7 +2016,7 @@ dependencies = [
 [[package]]
 name = "rustpython-common"
 version = "0.0.0"
-source = "git+https://github.com/RustPython/RustPython.git?rev=4d53c7cb27c0379adf8b51c4d3d0d2174f41d590#4d53c7cb27c0379adf8b51c4d3d0d2174f41d590"
+source = "git+https://github.com/RustPython/RustPython.git?rev=d532160333ffeb6dbeca2c2728c2391cd1e53b7f#d532160333ffeb6dbeca2c2728c2391cd1e53b7f"
 dependencies = [
 "ascii",
 "bitflags",
@@ -2040,7 +2041,7 @@ dependencies = [
 [[package]]
 name = "rustpython-compiler-core"
 version = "0.1.2"
-source = "git+https://github.com/RustPython/RustPython.git?rev=4d53c7cb27c0379adf8b51c4d3d0d2174f41d590#4d53c7cb27c0379adf8b51c4d3d0d2174f41d590"
+source = "git+https://github.com/RustPython/RustPython.git?rev=d532160333ffeb6dbeca2c2728c2391cd1e53b7f#d532160333ffeb6dbeca2c2728c2391cd1e53b7f"
 dependencies = [
 "bincode",
 "bitflags",
@@ -2057,7 +2058,7 @@ dependencies = [
 [[package]]
 name = "rustpython-parser"
 version = "0.1.2"
-source = "git+https://github.com/RustPython/RustPython.git?rev=4d53c7cb27c0379adf8b51c4d3d0d2174f41d590#4d53c7cb27c0379adf8b51c4d3d0d2174f41d590"
+source = "git+https://github.com/RustPython/RustPython.git?rev=d532160333ffeb6dbeca2c2728c2391cd1e53b7f#d532160333ffeb6dbeca2c2728c2391cd1e53b7f"
 dependencies = [
 "ahash",
 "anyhow",
@@ -2496,14 +2497,27 @@ dependencies = [
 ]

 [[package]]
-name = "toml"
-version = "0.5.10"
+name = "toml_datetime"
+version = "0.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1333c76748e868a4d9d1017b5ab53171dfd095f70c712fdb4653a406547f598f"
+checksum = "808b51e57d0ef8f71115d8f3a01e7d3750d01c79cac4b3eda910f4389fdf92fd"
 dependencies = [
 "serde",
 ]

+[[package]]
+name = "toml_edit"
+version = "0.17.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a34cc558345efd7e88b9eda9626df2138b80bb46a7606f695e751c892bc7dac6"
+dependencies = [
+ "indexmap",
+ "itertools",
+ "nom8",
+ "serde",
+ "toml_datetime",
+]
+
 [[package]]
 name = "twox-hash"
 version = "1.6.3"
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -6,7 +6,7 @@ members = [

 [package]
 name = "ruff"
-version = "0.0.211"
+version = "0.0.219"
 authors = ["Charlie Marsh <charlie.r.marsh@gmail.com>"]
 edition = "2021"
 rust-version = "1.65.0"
@@ -19,6 +19,7 @@ license = "MIT"
 [lib]
 name = "ruff"
 crate-type = ["cdylib", "rlib"]
+doctest = false

 [dependencies]
 annotate-snippets = { version = "0.9.1", features = ["color"] }
@@ -29,7 +30,7 @@ bitflags = { version = "1.3.2" }
 cachedir = { version = "0.3.0" }
 cfg-if = { version = "1.0.0" }
 chrono = { version = "0.4.21", default-features = false, features = ["clock"] }
-clap = { version = "4.0.1", features = ["derive"] }
+clap = { version = "4.0.1", features = ["derive", "env"] }
 clap_complete_command = { version = "0.4.0" }
 colored = { version = "2.0.0" }
 dirs = { version = "4.0.0" }
@@ -51,11 +52,11 @@ path-absolutize = { version = "3.0.14", features = ["once_cell_cache", "use_unix
 quick-junit = { version = "0.3.2" }
 regex = { version = "1.6.0" }
 ropey = { version = "1.5.0", features = ["cr_lines", "simd"], default-features = false }
-ruff_macros = { version = "0.0.211", path = "ruff_macros" }
+ruff_macros = { version = "0.0.219", path = "ruff_macros" }
 rustc-hash = { version = "1.1.0" }
-rustpython-ast = { features = ["unparse"], git = "https://github.com/RustPython/RustPython.git", rev = "4d53c7cb27c0379adf8b51c4d3d0d2174f41d590" }
-rustpython-common = { git = "https://github.com/RustPython/RustPython.git", rev = "4d53c7cb27c0379adf8b51c4d3d0d2174f41d590" }
-rustpython-parser = { features = ["lalrpop"], git = "https://github.com/RustPython/RustPython.git", rev = "4d53c7cb27c0379adf8b51c4d3d0d2174f41d590" }
+rustpython-ast = { features = ["unparse"], git = "https://github.com/RustPython/RustPython.git", rev = "d532160333ffeb6dbeca2c2728c2391cd1e53b7f" }
+rustpython-common = { git = "https://github.com/RustPython/RustPython.git", rev = "d532160333ffeb6dbeca2c2728c2391cd1e53b7f" }
+rustpython-parser = { features = ["lalrpop"], git = "https://github.com/RustPython/RustPython.git", rev = "d532160333ffeb6dbeca2c2728c2391cd1e53b7f" }
 schemars = { version = "0.8.11" }
 semver = { version = "1.0.16" }
 serde = { version = "1.0.147", features = ["derive"] }
@@ -66,7 +67,7 @@ strum = { version = "0.24.1", features = ["strum_macros"] }
 strum_macros = { version = "0.24.3" }
 textwrap = { version = "0.16.0" }
 titlecase = { version = "2.2.1" }
-toml = { version = "0.5.9" }
+toml_edit = { version = "0.17.1", features = ["easy"] }
 walkdir = { version = "2.3.2" }

 [target.'cfg(not(target_family = "wasm"))'.dependencies]
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 # Ruff

-[![Ruff](https://img.shields.io/endpoint?url=https://raw.githubusercontent.com/charliermarsh/ruff/main/assets/badge/v0.json)](https://github.com/charliermarsh/ruff)
+[![Ruff](https://img.shields.io/endpoint?url=https://raw.githubusercontent.com/charliermarsh/ruff/main/assets/badge/v1.json)](https://github.com/charliermarsh/ruff)
 [![image](https://img.shields.io/pypi/v/ruff.svg)](https://pypi.python.org/pypi/ruff)
 [![image](https://img.shields.io/pypi/l/ruff.svg)](https://pypi.python.org/pypi/ruff)
 [![image](https://img.shields.io/pypi/pyversions/ruff.svg)](https://pypi.python.org/pypi/ruff)
@@ -164,9 +164,9 @@ pacman -S ruff
 To run Ruff, try any of the following:

 ```shell
-ruff path/to/code/to/check.py  # Run Ruff over `check.py`
-ruff path/to/code/             # Run Ruff over all files in `/path/to/code` (and any subdirectories)
-ruff path/to/code/*.py         # Run Ruff over all `.py` files in `/path/to/code`
+ruff path/to/code/to/lint.py  # Run Ruff over `lint.py`
+ruff path/to/code/            # Run Ruff over all files in `/path/to/code` (and any subdirectories)
+ruff path/to/code/*.py        # Run Ruff over all `.py` files in `/path/to/code`
 ```

 You can run Ruff in `--watch` mode to automatically re-run on-change:
@@ -180,7 +180,7 @@ Ruff also works with [pre-commit](https://pre-commit.com):
 ```yaml
 - repo: https://github.com/charliermarsh/ruff-pre-commit
  # Ruff version.
-  rev: 'v0.0.211'
+  rev: 'v0.0.219'
  hooks:
    - id: ruff
      # Respect `exclude` and `extend-exclude` settings.
@@ -237,9 +237,9 @@ target-version = "py310"
 max-complexity = 10
 ```

-As an example, the following would configure Ruff to: (1) avoid checking for line-length
-violations (`E501`); (2) never remove unused imports (`F401`); and (3) ignore import-at-top-of-file
-errors (`E402`) in `__init__.py` files:
+As an example, the following would configure Ruff to: (1) avoid enforcing line-length violations
+(`E501`); (2) never remove unused imports (`F401`); and (3) ignore import-at-top-of-file violations
+(`E402`) in `__init__.py` files:

 ```toml
 [tool.ruff]
@@ -269,16 +269,16 @@ select = ["E", "F", "Q"]
 docstring-quotes = "double"
 ```

-Ruff mirrors Flake8's error code system, in which each error code consists of a one-to-three letter
-prefix, followed by three digits (e.g., `F401`). The prefix indicates that "source" of the error
-code (e.g., `F` for Pyflakes, `E` for `pycodestyle`, `ANN` for `flake8-annotations`). The set of
-enabled errors is determined by the `select` and `ignore` options, which support both the full
-error code (e.g., `F401`) and the prefix (e.g., `F`).
+Ruff mirrors Flake8's rule code system, in which each rule code consists of a one-to-three letter
+prefix, followed by three digits (e.g., `F401`). The prefix indicates that "source" of the rule
+(e.g., `F` for Pyflakes, `E` for `pycodestyle`, `ANN` for `flake8-annotations`). The set of enabled
+rules is determined by the `select` and `ignore` options, which support both the full code (e.g.,
+`F401`) and the prefix (e.g., `F`).

-As a special-case, Ruff also supports the `ALL` error code, which enables all error codes. Note that
-some of the `pydocstyle` error codes are conflicting (e.g., `D203` and `D211`) as they represent
-alternative docstring formats. Enabling `ALL` without further configuration may result in suboptimal
-behavior, especially for the `pydocstyle` plugin.
+As a special-case, Ruff also supports the `ALL` code, which enables all rules. Note that some of the
+`pydocstyle` rules conflict (e.g., `D203` and `D211`) as they represent alternative docstring
+formats. Enabling `ALL` without further configuration may result in suboptimal behavior, especially
+for the `pydocstyle` plugin.

 As an alternative to `pyproject.toml`, Ruff will also respect a `ruff.toml` file, which implements
 an equivalent schema (though the `[tool.ruff]` hierarchy can be omitted). For example, the
@@ -312,7 +312,7 @@ ruff path/to/code/ --select F401 --select F403
 See `ruff --help` for more:

 <!-- Begin auto-generated cli help. -->
-```shell
+```
 Ruff: An extremely fast Python linter.

 Usage: ruff [OPTIONS] [FILES]...
@@ -326,45 +326,47 @@ Options:
  -v, --verbose
          Enable verbose logging
  -q, --quiet
-          Only log errors
+          Print lint violations, but nothing else
  -s, --silent
-          Disable all logging (but still exit with status code "1" upon detecting errors)
+          Disable all logging (but still exit with status code "1" upon detecting lint violations)
  -e, --exit-zero
-          Exit with status code "0", even upon detecting errors
+          Exit with status code "0", even upon detecting lint violations
  -w, --watch
          Run in watch mode by re-running whenever files change
      --fix
-          Attempt to automatically fix lint errors
+          Attempt to automatically fix lint violations
      --fix-only
-          Fix any fixable lint errors, but don't report on leftover violations. Implies `--fix`
+          Fix any fixable lint violations, but don't report on leftover violations. Implies `--fix`
      --diff
          Avoid writing any fixed files back; instead, output a diff for each changed file to stdout
  -n, --no-cache
          Disable cache reads
-      --select <SELECT>
-          Comma-separated list of error codes to enable (or ALL, to enable all checks)
-      --extend-select <EXTEND_SELECT>
-          Like --select, but adds additional error codes on top of the selected ones
-      --ignore <IGNORE>
-          Comma-separated list of error codes to disable
-      --extend-ignore <EXTEND_IGNORE>
-          Like --ignore, but adds additional error codes on top of the ignored ones
-      --exclude <EXCLUDE>
-          List of paths, used to exclude files and/or directories from checks
-      --extend-exclude <EXTEND_EXCLUDE>
-          Like --exclude, but adds additional files and directories on top of the excluded ones
-      --fixable <FIXABLE>
-          List of error codes to treat as eligible for autofix. Only applicable when autofix itself is enabled (e.g., via `--fix`)
-      --unfixable <UNFIXABLE>
-          List of error codes to treat as ineligible for autofix. Only applicable when autofix itself is enabled (e.g., via `--fix`)
+      --isolated
+          Ignore all configuration files
+      --select <RULE_CODE>
+          Comma-separated list of rule codes to enable (or ALL, to enable all rules)
+      --extend-select <RULE_CODE>
+          Like --select, but adds additional rule codes on top of the selected ones
+      --ignore <RULE_CODE>
+          Comma-separated list of rule codes to disable
+      --extend-ignore <RULE_CODE>
+          Like --ignore, but adds additional rule codes on top of the ignored ones
+      --exclude <FILE_PATTERN>
+          List of paths, used to omit files and/or directories from analysis
+      --extend-exclude <FILE_PATTERN>
+          Like --exclude, but adds additional files and directories on top of those already excluded
+      --fixable <RULE_CODE>
+          List of rule codes to treat as eligible for autofix. Only applicable when autofix itself is enabled (e.g., via `--fix`)
+      --unfixable <RULE_CODE>
+          List of rule codes to treat as ineligible for autofix. Only applicable when autofix itself is enabled (e.g., via `--fix`)
      --per-file-ignores <PER_FILE_IGNORES>
          List of mappings from file pattern to code to exclude
      --format <FORMAT>
-          Output serialization format for error messages [possible values: text, json, junit, grouped, github, gitlab]
+          Output serialization format for violations [env: RUFF_FORMAT=] [possible values: text, json, junit, grouped, github, gitlab]
      --stdin-filename <STDIN_FILENAME>
          The name of the file when passing it through stdin
      --cache-dir <CACHE_DIR>
-          Path to the cache directory
+          Path to the cache directory [env: RUFF_CACHE_DIR=]
      --show-source
          Show violations with source code
      --respect-gitignore
@@ -378,7 +380,7 @@ Options:
      --target-version <TARGET_VERSION>
          The minimum Python version that should be supported
      --line-length <LINE_LENGTH>
-          Set the line-length for length-associated checks and automatic formatting
+          Set the line-length for length-associated rules and automatic formatting
      --max-complexity <MAX_COMPLEXITY>
          Maximum McCabe complexity allowed for a given function
      --add-noqa
@@ -390,7 +392,7 @@ Options:
      --show-files
          See the files Ruff will be run against with the current settings
      --show-settings
-          See the settings Ruff will use to check a given Python file
+          See the settings Ruff will use to lint a given Python file
  -h, --help
          Print help information
  -V, --version
@@ -447,16 +449,16 @@ in each directory's `pyproject.toml` file.
 By default, Ruff will also skip any files that are omitted via `.ignore`, `.gitignore`,
 `.git/info/exclude`, and global `gitignore` files (see: [`respect-gitignore`](#respect-gitignore)).

-Files that are passed to `ruff` directly are always checked, regardless of the above criteria.
-For example, `ruff /path/to/excluded/file.py` will always check `file.py`.
+Files that are passed to `ruff` directly are always linted, regardless of the above criteria.
+For example, `ruff /path/to/excluded/file.py` will always lint `file.py`.

 ### Ignoring errors

-To omit a lint check entirely, add it to the "ignore" list via [`ignore`](#ignore) or
+To omit a lint rule entirely, add it to the "ignore" list via [`ignore`](#ignore) or
 [`extend-ignore`](#extend-ignore), either on the command-line or in your `pyproject.toml` file.

-To ignore an error inline, Ruff uses a `noqa` system similar to [Flake8](https://flake8.pycqa.org/en/3.1.1/user/ignoring-errors.html).
-To ignore an individual error, add `# noqa: {code}` to the end of the line, like so:
+To ignore a violation inline, Ruff uses a `noqa` system similar to [Flake8](https://flake8.pycqa.org/en/3.1.1/user/ignoring-errors.html).
+To ignore an individual violation, add `# noqa: {code}` to the end of the line, like so:

 ```python
 # Ignore F841.
@@ -465,7 +467,7 @@ x = 1  # noqa: F841
 # Ignore E741 and F841.
 i = 1  # noqa: E741, F841

-# Ignore _all_ errors.
+# Ignore _all_ violations.
 x = 1  # noqa
 ```

@@ -479,9 +481,9 @@ Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor i
 """  # noqa: E501
 ```

-To ignore all errors across an entire file, Ruff supports Flake8's `# flake8: noqa` directive (or,
-equivalently, `# ruff: noqa`). Adding either of those directives to any part of a file will disable
-error reporting for the entire file.
+To ignore all violations across an entire file, Ruff supports Flake8's `# flake8: noqa` directive
+(or, equivalently, `# ruff: noqa`). Adding either of those directives to any part of a file will
+disable enforcement across the entire file.

 For targeted exclusions across entire files (e.g., "Ignore all F841 violations in
 `/path/to/file.py`"), see the [`per-file-ignores`](#per-file-ignores) configuration setting.
@@ -500,8 +502,8 @@ for more.

 Ruff supports several workflows to aid in `noqa` management.

-First, Ruff provides a special error code, `RUF100`, to enforce that your `noqa` directives are
-"valid", in that the errors they _say_ they ignore are actually being triggered on that line (and
+First, Ruff provides a special rule code, `RUF100`, to enforce that your `noqa` directives are
+"valid", in that the violations they _say_ they ignore are actually being triggered on that line (and
 thus suppressed). You can run `ruff /path/to/file.py --extend-select RUF100` to flag unused `noqa`
 directives.

@@ -511,13 +513,13 @@ You can run `ruff /path/to/file.py --extend-select RUF100 --fix` to automaticall

 Third, Ruff can _automatically add_ `noqa` directives to all failing lines. This is useful when
 migrating a new codebase to Ruff. You can run `ruff /path/to/file.py --add-noqa` to automatically
-add `noqa` directives to all failing lines, with the appropriate error codes.
+add `noqa` directives to all failing lines, with the appropriate rule codes.

 ## Supported Rules

 Regardless of the rule's origin, Ruff re-implements every rule in Rust as a first-party feature.

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

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

@@ -551,8 +553,8 @@ For more, see [Pyflakes](https://pypi.org/project/pyflakes/2.5.0/) on PyPI.
 | F524 | StringDotFormatMissingArguments | '...'.format(...) is missing argument(s) for placeholder(s): ... |  |
 | F525 | StringDotFormatMixingAutomatic | '...'.format(...) mixes automatic and manual numbering |  |
 | F541 | FStringMissingPlaceholders | f-string without any placeholders | 🛠 |
-| F601 | MultiValueRepeatedKeyLiteral | Dictionary key literal repeated |  |
-| F602 | MultiValueRepeatedKeyVariable | Dictionary key `...` repeated |  |
+| F601 | MultiValueRepeatedKeyLiteral | Dictionary key literal `...` repeated | 🛠 |
+| F602 | MultiValueRepeatedKeyVariable | Dictionary key `...` repeated | 🛠 |
 | F621 | ExpressionsInStarAssignment | Too many expressions in star-unpacking assignment |  |
 | F622 | TwoStarredExpressions | Two starred expressions in assignment |  |
 | F631 | AssertTuple | Assert test is a non-empty tuple, which is always `True` |  |
@@ -569,7 +571,7 @@ For more, see [Pyflakes](https://pypi.org/project/pyflakes/2.5.0/) on PyPI.
 | F821 | UndefinedName | Undefined name `...` |  |
 | F822 | UndefinedExport | Undefined name `...` in `__all__` |  |
 | F823 | UndefinedLocal | Local variable `...` referenced before assignment |  |
-| F841 | UnusedVariable | Local variable `...` is assigned to but never used |  |
+| F841 | UnusedVariable | Local variable `...` is assigned to but never used | 🛠 |
 | F842 | UnusedAnnotation | Local variable `...` is annotated but never used |  |
 | F901 | RaiseNotImplemented | `raise NotImplemented` should be `raise NotImplementedError` | 🛠 |

@@ -595,6 +597,7 @@ For more, see [pycodestyle](https://pypi.org/project/pycodestyle/2.9.1/) on PyPI
 | E902 | IOError | IOError: `...` |  |
 | E999 | SyntaxError | SyntaxError: `...` |  |
 | W292 | NoNewLineAtEndOfFile | No newline at end of file | 🛠 |
+| W505 | DocLineTooLong | Doc line too long (89 > 88 characters) |  |
 | W605 | InvalidEscapeSequence | Invalid escape sequence: '\c' | 🛠 |

 ### mccabe (C90)
@@ -612,6 +615,7 @@ For more, see [isort](https://pypi.org/project/isort/5.10.1/) on PyPI.
 | Code | Name | Message | Fix |
 | ---- | ---- | ------- | --- |
 | I001 | UnsortedImports | Import block is un-sorted or un-formatted | 🛠 |
+| I002 | MissingRequiredImport | Missing required import: `from __future__ import ...` | 🛠 |

 ### pydocstyle (D)

@@ -632,7 +636,7 @@ For more, see [pydocstyle](https://pypi.org/project/pydocstyle/6.1.1/) on PyPI.
 | D202 | NoBlankLineAfterFunction | No blank lines allowed after function docstring (found 1) | 🛠 |
 | D203 | OneBlankLineBeforeClass | 1 blank line required before class docstring | 🛠 |
 | D204 | OneBlankLineAfterClass | 1 blank line required after class docstring | 🛠 |
-| D205 | BlankLineAfterSummary | 1 blank line required between summary line and description | 🛠 |
+| D205 | BlankLineAfterSummary | 1 blank line required between summary line and description (found 2) | 🛠 |
 | D206 | IndentWithSpaces | Docstring should be indented with spaces, not tabs |  |
 | D207 | NoUnderIndentation | Docstring is under-indented | 🛠 |
 | D208 | NoOverIndentation | Docstring is over-indented | 🛠 |
@@ -699,6 +703,7 @@ For more, see [pyupgrade](https://pypi.org/project/pyupgrade/3.2.0/) on PyPI.
 | UP027 | RewriteListComprehension | Replace unpacked list comprehension with a generator expression | 🛠 |
 | UP028 | RewriteYieldFrom | Replace `yield` over `for` loop with `yield from` | 🛠 |
 | UP029 | UnnecessaryBuiltinImport | Unnecessary builtin import: `...` | 🛠 |
+| UP030 | FormatLiterals | Use implicit references for positional format fields | 🛠 |

 ### pep8-naming (N)

@@ -767,10 +772,16 @@ For more, see [flake8-bandit](https://pypi.org/project/flake8-bandit/4.1.1/) on
 | S102 | ExecUsed | Use of `exec` detected |  |
 | S103 | BadFilePermissions | `os.chmod` setting a permissive mask `0o777` on file or directory |  |
 | S104 | HardcodedBindAllInterfaces | Possible binding to all interfaces |  |
-| S105 | HardcodedPasswordString | Possible hardcoded password: `"..."` |  |
-| S106 | HardcodedPasswordFuncArg | Possible hardcoded password: `"..."` |  |
-| S107 | HardcodedPasswordDefault | Possible hardcoded password: `"..."` |  |
-| S108 | HardcodedTempFile | Probable insecure usage of temp file/directory: `"..."` |  |
+| S105 | HardcodedPasswordString | Possible hardcoded password: "..." |  |
+| S106 | HardcodedPasswordFuncArg | Possible hardcoded password: "..." |  |
+| S107 | HardcodedPasswordDefault | Possible hardcoded password: "..." |  |
+| S108 | HardcodedTempFile | Probable insecure usage of temporary file or directory: "..." |  |
+| S113 | RequestWithoutTimeout | Probable use of requests call without timeout |  |
+| S324 | HashlibInsecureHashFunction | Probable use of insecure hash functions in `hashlib`: "..." |  |
+| S501 | RequestWithNoCertValidation | Probable use of `...` call with `verify=False` disabling SSL certificate checks |  |
+| S506 | UnsafeYAMLLoad | Probable use of unsafe `yaml.load`. Allows instantiation of arbitrary objects. Consider `yaml.safe_load`. |  |
+| S508 | SnmpInsecureVersion | The use of SNMPv1 and SNMPv2 is insecure. Use SNMPv3 if able. |  |
+| S509 | SnmpWeakCryptography | You should not use SNMPv3 without encryption. `noAuthNoPriv` & `authNoPriv` is insecure. |  |

 ### flake8-blind-except (BLE)

@@ -914,23 +925,23 @@ For more, see [flake8-pytest-style](https://pypi.org/project/flake8-pytest-style
 | PT005 | IncorrectFixtureNameUnderscore | Fixture `...` returns a value, remove leading underscore |  |
 | PT006 | ParametrizeNamesWrongType | Wrong name(s) type in `@pytest.mark.parametrize`, expected `tuple` | 🛠 |
 | PT007 | ParametrizeValuesWrongType | Wrong values type in `@pytest.mark.parametrize` expected `list` of `tuple` |  |
-| PT008 | PatchWithLambda | Use `return_value=` instead of patching with lambda |  |
-| PT009 | UnittestAssertion | Use a regular assert instead of unittest-style '...' |  |
+| PT008 | PatchWithLambda | Use `return_value=` instead of patching with `lambda` |  |
+| PT009 | UnittestAssertion | Use a regular `assert` instead of unittest-style `...` | 🛠 |
 | PT010 | RaisesWithoutException | set the expected exception in `pytest.raises()` |  |
 | PT011 | RaisesTooBroad | `pytest.raises(...)` is too broad, set the `match` parameter or use a more specific exception |  |
 | PT012 | RaisesWithMultipleStatements | `pytest.raises()` block should contain a single simple statement |  |
 | PT013 | IncorrectPytestImport | Found incorrect import of pytest, use simple `import pytest` instead |  |
 | PT015 | AssertAlwaysFalse | Assertion always fails, replace with `pytest.fail()` |  |
 | PT016 | FailWithoutMessage | No message passed to `pytest.fail()` |  |
-| PT017 | AssertInExcept | Found assertion on exception ... in except block, use pytest.raises() instead |  |
+| PT017 | AssertInExcept | Found assertion on exception `...` in except block, use `pytest.raises()` instead |  |
 | PT018 | CompositeAssertion | Assertion should be broken down into multiple parts |  |
-| PT019 | FixtureParamWithoutValue | Fixture ... without value is injected as parameter, use @pytest.mark.usefixtures instead |  |
+| PT019 | FixtureParamWithoutValue | Fixture `...` without value is injected as parameter, use `@pytest.mark.usefixtures` instead |  |
 | PT020 | DeprecatedYieldFixture | `@pytest.yield_fixture` is deprecated, use `@pytest.fixture` |  |
 | PT021 | FixtureFinalizerCallback | Use `yield` instead of `request.addfinalizer` |  |
-| PT022 | UselessYieldFixture | No teardown in fixture ..., use `return` instead of `yield` | 🛠 |
+| PT022 | UselessYieldFixture | No teardown in fixture `...`, use `return` instead of `yield` | 🛠 |
 | PT023 | IncorrectMarkParenthesesStyle | Use `@pytest.mark....` over `@pytest.mark....()` | 🛠 |
-| PT024 | UnnecessaryAsyncioMarkOnFixture | `pytest.mark.asyncio` is unnecessary for fixtures |  |
-| PT025 | ErroneousUseFixturesOnFixture | `pytest.mark.usefixtures` has no effect on fixtures |  |
+| PT024 | UnnecessaryAsyncioMarkOnFixture | `pytest.mark.asyncio` is unnecessary for fixtures | 🛠 |
+| PT025 | ErroneousUseFixturesOnFixture | `pytest.mark.usefixtures` has no effect on fixtures | 🛠 |
 | PT026 | UseFixturesWithoutParameters | Useless `pytest.mark.usefixtures` without parameters | 🛠 |

 ### flake8-quotes (Q)
@@ -965,18 +976,31 @@ For more, see [flake8-simplify](https://pypi.org/project/flake8-simplify/0.19.3/

 | Code | Name | Message | Fix |
 | ---- | ---- | ------- | --- |
+| SIM115 | OpenFileWithContextHandler | Use context handler for opening files |  |
+| SIM101 | DuplicateIsinstanceCall | Multiple `isinstance` calls for `...`, merge into a single call | 🛠 |
 | SIM102 | NestedIfStatements | Use a single `if` statement instead of nested `if` statements |  |
+| SIM103 | ReturnBoolConditionDirectly | Return the condition `...` directly | 🛠 |
 | SIM105 | UseContextlibSuppress | Use `contextlib.suppress(...)` instead of try-except-pass |  |
 | SIM107 | ReturnInTryExceptFinally | Don't use `return` in `try`/`except` and `finally` |  |
+| SIM108 | UseTernaryOperator | Use ternary operator `...` instead of if-else-block | 🛠 |
+| SIM109 | CompareWithTuple | Use `value in (..., ...)` instead of `value == ... or value == ...` | 🛠 |
 | SIM110 | ConvertLoopToAny | Use `return any(x for x in y)` instead of `for` loop | 🛠 |
 | SIM111 | ConvertLoopToAll | Use `return all(x for x in y)` instead of `for` loop | 🛠 |
+| SIM112 | UseCapitalEnvironmentVariables | Use capitalized environment variable `...` instead of `...` | 🛠 |
 | SIM117 | MultipleWithStatements | Use a single `with` statement with multiple contexts instead of nested `with` statements |  |
 | SIM118 | KeyInDict | Use `key in dict` instead of `key in dict.keys()` | 🛠 |
+| SIM201 | NegateEqualOp | Use `left != right` instead of `not left == right` | 🛠 |
+| SIM202 | NegateNotEqualOp | Use `left == right` instead of `not left != right` | 🛠 |
+| SIM208 | DoubleNegation | Use `expr` instead of `not (not expr)` | 🛠 |
+| SIM210 | IfExprWithTrueFalse | Use `bool(expr)` instead of `True if expr else False` | 🛠 |
+| SIM211 | IfExprWithFalseTrue | Use `not expr` instead of `False if expr else True` | 🛠 |
+| SIM212 | IfExprWithTwistedArms | Use `b if b else a` instead of `a if not b else b` | 🛠 |
 | SIM220 | AAndNotA | Use `False` instead of `... and not ...` | 🛠 |
 | SIM221 | AOrNotA | Use `True` instead of `... or not ...` | 🛠 |
 | SIM222 | OrTrue | Use `True` instead of `... or True` | 🛠 |
 | SIM223 | AndFalse | Use `False` instead of `... and False` | 🛠 |
 | SIM300 | YodaConditions | Yoda conditions are discouraged, use `left == right` instead | 🛠 |
+| SIM401 | DictGetWithDefault | Use `var = dict.get(key, "default")` instead of an `if` block | 🛠 |

 ### flake8-tidy-imports (TID)

@@ -1050,8 +1074,8 @@ For more, see [pygrep-hooks](https://github.com/pre-commit/pygrep-hooks) on GitH
 | ---- | ---- | ------- | --- |
 | PGH001 | NoEval | No builtin `eval()` allowed |  |
 | PGH002 | DeprecatedLogWarn | `warn` is deprecated in favor of `warning` |  |
-| PGH003 | BlanketTypeIgnore | Use specific error codes when ignoring type issues |  |
-| PGH004 | BlanketNOQA | Use specific error codes when using `noqa` |  |
+| PGH003 | BlanketTypeIgnore | Use specific rule codes when ignoring type issues |  |
+| PGH004 | BlanketNOQA | Use specific rule codes when using `noqa` |  |

 ### Pylint (PLC, PLE, PLR, PLW)

@@ -1317,8 +1341,9 @@ jobs:
        run: |
          python -m pip install --upgrade pip
          pip install ruff
+      # Include `--format=github` to enable automatic inline annotations.
      - name: Run Ruff
-        run: ruff .
+        run: ruff --format=github .
 ```

 ## FAQ
@@ -1376,7 +1401,7 @@ natively, including:
 - [`pyupgrade`](https://pypi.org/project/pyupgrade/) ([#827](https://github.com/charliermarsh/ruff/issues/827))
 - [`yesqa`](https://github.com/asottile/yesqa)

-Note that, in some cases, Ruff uses different error code prefixes than would be found in the
+Note that, in some cases, Ruff uses different rule codes and prefixes than would be found in the
 originating Flake8 plugins. For example, Ruff uses `TID252` to represent the `I252` rule from
 `flake8-tidy-imports`. This helps minimize conflicts across plugins and allows any individual plugin
 to be toggled on or off with a single (e.g.) `--select TID`, as opposed to `--select I2` (to avoid
@@ -1401,9 +1426,9 @@ At time of writing, Pylint implements 409 total rules, while Ruff implements 224
 at least 60 overlap with the Pylint rule set. Subjectively, Pylint tends to implement more rules
 based on type inference (e.g., validating the number of arguments in a function call).

-Like Flake8, Pylint supports plugins (called "checkers"), while Ruff implements all checks natively.
+Like Flake8, Pylint supports plugins (called "checkers"), while Ruff implements all rules natively.

-Unlike Pylint, Ruff is capable of automatically fixing its own lint errors.
+Unlike Pylint, Ruff is capable of automatically fixing its own lint violations.

 Pylint parity is being tracked in [#689](https://github.com/charliermarsh/ruff/issues/689).

@@ -1516,7 +1541,7 @@ For example, if you're coming from `flake8-docstrings`, and your originating con
 `--docstring-convention=numpy`, you'd instead set `convention = "numpy"` in your `pyproject.toml`,
 as above.

-Alongside `convention`, you'll want to explicitly enable the `D` error code class, like so:
+Alongside `convention`, you'll want to explicitly enable the `D` rule code prefix, like so:

 ```toml
 [tool.ruff]
@@ -1722,6 +1747,24 @@ allowed-confusables = ["−", "ρ", "∗"]

 ---

+#### [`builtins`](#builtins)
+
+A list of builtins to treat as defined references, in addition to the
+system builtins.
+
+**Default value**: `[]`
+
+**Type**: `Vec<String>`
+
+**Example usage**:
+
+```toml
+[tool.ruff]
+builtins = ["_"]
+```
+
+---
+
 #### [`cache-dir`](#cache-dir)

 A path to the cache directory.
@@ -1751,7 +1794,7 @@ cache-dir = "~/.cache/ruff"
 #### [`dummy-variable-rgx`](#dummy-variable-rgx)

 A regular expression used to identify "dummy" variables, or those which
-should be ignored when evaluating (e.g.) unused-variable checks. The
+should be ignored when enforcing (e.g.) unused-variable rules. The
 default expression matches `_`, `__`, and `_var`, but not `_var_`.

 **Default value**: `"^(_+|(_+[a-zA-Z0-9_]*[a-zA-Z0-9]+?))$"`
@@ -1782,6 +1825,8 @@ Exclusions are based on globs, and can be either:
  `directory`). Note that these paths are relative to the project root
  (e.g., the directory containing your `pyproject.toml`).

+For more information on the glob syntax, refer to the [`globset` documentation](https://docs.rs/globset/latest/globset/#syntax).
+
 Note that you'll typically want to use
 [`extend-exclude`](#extend-exclude) to modify the excluded paths.

@@ -1829,6 +1874,18 @@ line-length = 100
 A list of file patterns to omit from linting, in addition to those
 specified by `exclude`.

+Exclusions are based on globs, and can be either:
+
+- Single-path patterns, like `.mypy_cache` (to exclude any directory
+  named `.mypy_cache` in the tree), `foo.py` (to exclude any file named
+  `foo.py`), or `foo_*.py` (to exclude any file matching `foo_*.py` ).
+- Relative patterns, like `directory/foo.py` (to exclude that specific
+  file) or `directory/*.py` (to exclude any Python files in
+  `directory`). Note that these paths are relative to the project root
+  (e.g., the directory containing your `pyproject.toml`).
+
+For more information on the glob syntax, refer to the [`globset` documentation](https://docs.rs/globset/latest/globset/#syntax).
+
 **Default value**: `[]`

 **Type**: `Vec<FilePattern>`
@@ -1845,18 +1902,18 @@ extend-exclude = ["tests", "src/bad.py"]

 #### [`extend-ignore`](#extend-ignore)

-A list of check code prefixes to ignore, in addition to those specified
-by `ignore`.
+A list of rule codes or prefixes to ignore, in addition to those
+specified by `ignore`.

 **Default value**: `[]`

-**Type**: `Vec<CheckCodePrefix>`
+**Type**: `Vec<RuleCodePrefix>`

 **Example usage**:

 ```toml
 [tool.ruff]
-# Skip unused variable checks (`F841`).
+# Skip unused variable rules (`F841`).
 extend-ignore = ["F841"]
 ```

@@ -1864,12 +1921,12 @@ extend-ignore = ["F841"]

 #### [`extend-select`](#extend-select)

-A list of check code prefixes to enable, in addition to those specified
-by `select`.
+A list of rule codes or prefixes to enable, in addition to those
+specified by `select`.

 **Default value**: `[]`

-**Type**: `Vec<CheckCodePrefix>`
+**Type**: `Vec<RuleCodePrefix>`

 **Example usage**:

@@ -1883,10 +1940,10 @@ extend-select = ["B", "Q"]

 #### [`external`](#external)

-A list of check codes that are unsupported by Ruff, but should be
+A list of rule codes that are unsupported by Ruff, but should be
 preserved when (e.g.) validating `# noqa` directives. Useful for
 retaining `# noqa` directives that cover plugins not yet implemented
-in Ruff.
+by Ruff.

 **Default value**: `[]`

@@ -1940,17 +1997,17 @@ fix-only = true

 #### [`fixable`](#fixable)

-A list of check code prefixes to consider autofix-able.
+A list of rule codes or prefixes to consider autofixable.

 **Default value**: `["A", "ANN", "ARG", "B", "BLE", "C", "D", "E", "ERA", "F", "FBT", "I", "ICN", "N", "PGH", "PLC", "PLE", "PLR", "PLW", "Q", "RET", "RUF", "S", "T", "TID", "UP", "W", "YTT"]`

-**Type**: `Vec<CheckCodePrefix>`
+**Type**: `Vec<RuleCodePrefix>`

 **Example usage**:

 ```toml
 [tool.ruff]
-# Only allow autofix behavior for `E` and `F` checks.
+# Only allow autofix behavior for `E` and `F` rules.
 fixable = ["E", "F"]
 ```

@@ -2006,23 +2063,23 @@ format = "grouped"

 #### [`ignore`](#ignore)

-A list of check code prefixes to ignore. Prefixes can specify exact
-checks (like `F841`), entire categories (like `F`), or anything in
+A list of rule codes or prefixes to ignore. Prefixes can specify exact
+rules (like `F841`), entire categories (like `F`), or anything in
 between.

-When breaking ties between enabled and disabled checks (via `select` and
+When breaking ties between enabled and disabled rules (via `select` and
 `ignore`, respectively), more specific prefixes override less
 specific prefixes.

 **Default value**: `[]`

-**Type**: `Vec<CheckCodePrefix>`
+**Type**: `Vec<RuleCodePrefix>`

 **Example usage**:

 ```toml
 [tool.ruff]
-# Skip unused variable checks (`F841`).
+# Skip unused variable rules (`F841`).
 ignore = ["F841"]
 ```

@@ -2070,12 +2127,12 @@ line-length = 120

 #### [`per-file-ignores`](#per-file-ignores)

-A list of mappings from file pattern to check code prefixes to exclude,
-when considering any matching files.
+A list of mappings from file pattern to rule codes or prefixes to
+exclude, when considering any matching files.

 **Default value**: `{}`

-**Type**: `HashMap<String, Vec<CheckCodePrefix>>`
+**Type**: `HashMap<String, Vec<RuleCodePrefix>>`

 **Example usage**:

@@ -2129,17 +2186,17 @@ respect_gitignore = false

 #### [`select`](#select)

-A list of check code prefixes to enable. Prefixes can specify exact
-checks (like `F841`), entire categories (like `F`), or anything in
+A list of rule codes or prefixes to enable. Prefixes can specify exact
+rules (like `F841`), entire categories (like `F`), or anything in
 between.

-When breaking ties between enabled and disabled checks (via `select` and
+When breaking ties between enabled and disabled rules (via `select` and
 `ignore`, respectively), more specific prefixes override less
 specific prefixes.

 **Default value**: `["E", "F"]`

-**Type**: `Vec<CheckCodePrefix>`
+**Type**: `Vec<RuleCodePrefix>`

 **Example usage**:

@@ -2153,8 +2210,8 @@ select = ["E", "F", "B", "Q"]

 #### [`show-source`](#show-source)

-Whether to show source code snippets when reporting lint error
-violations (overridden by the `--show-source` command-line flag).
+Whether to show source code snippets when reporting lint violations
+(overridden by the `--show-source` command-line flag).

 **Default value**: `false`

@@ -2237,7 +2294,7 @@ target-version = "py37"
 A list of task tags to recognize (e.g., "TODO", "FIXME", "XXX").

 Comments starting with these tags will be ignored by commented-out code
-detection (`ERA`), and skipped by line-length checks (`E501`) if
+detection (`ERA`), and skipped by line-length rules (`E501`) if
 `ignore-overlong-task-comments` is set to `true`.

 **Default value**: `["TODO", "FIXME", "XXX"]`
@@ -2253,13 +2310,37 @@ task-tags = ["HACK"]

 ---

-#### [`unfixable`](#unfixable)
+#### [`typing-modules`](#typing-modules)

-A list of check code prefixes to consider un-autofix-able.
+A list of modules whose imports should be treated equivalently to
+members of the `typing` module.
+
+This is useful for ensuring proper type annotation inference for
+projects that re-export `typing` and `typing_extensions` members
+from a compatibility module. If omitted, any members imported from
+modules apart from `typing` and `typing_extensions` will be treated
+as ordinary Python objects.

 **Default value**: `[]`

-**Type**: `Vec<CheckCodePrefix>`
+**Type**: `Vec<String>`
+
+**Example usage**:
+
+```toml
+[tool.ruff]
+typing-modules = ["airflow.typing_compat"]
+```
+
+---
+
+#### [`unfixable`](#unfixable)
+
+A list of rule codes or prefixes to consider non-autofix-able.
+
+**Default value**: `[]`
+
+**Type**: `Vec<RuleCodePrefix>`

 **Example usage**:

@@ -2276,7 +2357,7 @@ unfixable = ["F401"]
 Enable or disable automatic update checks (overridden by the
 `--update-check` and `--no-update-check` command-line flags).

-**Default value**: `true`
+**Default value**: `false`

 **Type**: `bool`

@@ -2284,7 +2365,7 @@ Enable or disable automatic update checks (overridden by the

 ```toml
 [tool.ruff]
-update-check = false
+update-check = true
 ```

 ---
@@ -2329,7 +2410,7 @@ mypy-init-return = true

 #### [`suppress-dummy-args`](#suppress-dummy-args)

-Whether to suppress `ANN000`-level errors for arguments matching the
+Whether to suppress `ANN000`-level violations for arguments matching the
 "dummy" variable regex (like `_`).

 **Default value**: `false`
@@ -2347,8 +2428,8 @@ suppress-dummy-args = true

 #### [`suppress-none-returning`](#suppress-none-returning)

-Whether to suppress `ANN200`-level errors for functions that meet either
-of the following criteria:
+Whether to suppress `ANN200`-level violations for functions that meet
+either of the following criteria:

 - Contain no `return` statement.
 - Explicit `return` statement(s) all return `None` (explicitly or
@@ -2409,7 +2490,7 @@ extend-hardcoded-tmp-directory = ["/foo/bar"]
 #### [`extend-immutable-calls`](#extend-immutable-calls)

 Additional callable functions to consider "immutable" when evaluating,
-e.g., `no-mutable-default-argument` checks (`B006`).
+e.g., the `no-mutable-default-argument` rule (`B006`).

 **Default value**: `[]`

@@ -2459,9 +2540,10 @@ the `extend_aliases` option.

 ```toml
 [tool.ruff.flake8-import-conventions]
+[tool.ruff.flake8-import-conventions.aliases]
 # Declare the default aliases.
 altair = "alt"
-matplotlib.pyplot = "plt"
+"matplotlib.pyplot" = "plt"
 numpy = "np"
 pandas = "pd"
 seaborn = "sns"
@@ -2482,6 +2564,7 @@ will be added to the `aliases` mapping.

 ```toml
 [tool.ruff.flake8-import-conventions]
+[tool.ruff.flake8-import-conventions.extend-aliases]
 # Declare a custom alias for the `matplotlib` module.
 "dask.dataframe" = "dd"
 ```
@@ -2494,9 +2577,9 @@ will be added to the `aliases` mapping.

 Boolean flag specifying whether `@pytest.fixture()` without parameters
 should have parentheses. If the option is set to `true` (the
-default), `@pytest.fixture()` is valid and `@pytest.fixture` is an
-error. If set to `false`, `@pytest.fixture` is valid and
-`@pytest.fixture()` is an error.
+default), `@pytest.fixture()` is valid and `@pytest.fixture` is
+invalid. If set to `false`, `@pytest.fixture` is valid and
+`@pytest.fixture()` is invalid.

 **Default value**: `true`

@@ -2515,9 +2598,9 @@ fixture-parentheses = true

 Boolean flag specifying whether `@pytest.mark.foo()` without parameters
 should have parentheses. If the option is set to `true` (the
-default), `@pytest.mark.foo()` is valid and `@pytest.mark.foo` is an
-error. If set to `false`, `@pytest.fixture` is valid and
-`@pytest.mark.foo()` is an error.
+default), `@pytest.mark.foo()` is valid and `@pytest.mark.foo` is
+invalid. If set to `false`, `@pytest.fixture` is valid and
+`@pytest.mark.foo()` is invalid.

 **Default value**: `true`

@@ -2739,7 +2822,7 @@ ban-relative-imports = "all"
 #### [`banned-api`](#banned-api)

 Specific modules or module members that may not be imported or accessed.
-Note that this check is only meant to flag accidental uses,
+Note that this rule is only meant to flag accidental uses,
 and can be circumvented via `eval` or `importlib`.

 **Default value**: `{}`
@@ -2831,6 +2914,25 @@ force-single-line = true

 ---

+#### [`force-sort-within-sections`](#force-sort-within-sections)
+
+Don't sort straight-style imports (like `import sys`) before from-style
+imports (like `from itertools import groupby`). Instead, sort the
+imports by module, independent of import style.
+
+**Default value**: `false`
+
+**Type**: `bool`
+
+**Example usage**:
+
+```toml
+[tool.ruff.isort]
+force-sort-within-sections = true
+```
+
+---
+
 #### [`force-wrap-aliases`](#force-wrap-aliases)

 Force `import from` statements with multiple members and at least one
@@ -2918,6 +3020,23 @@ order-by-type = true

 ---

+#### [`required-imports`](#required-imports)
+
+Add the specified import line to all files.
+
+**Default value**: `[]`
+
+**Type**: `Vec<String>`
+
+**Example usage**:
+
+```toml
+[tool.ruff.isort]
+add-import = ["from __future__ import annotations"]
+```
+
+---
+
 #### [`single-line-exclusions`](#single-line-exclusions)

 One or more modules to exclude from the single line rule.
@@ -3040,7 +3159,7 @@ staticmethod-decorators = ["staticmethod", "stcmthd"]

 #### [`ignore-overlong-task-comments`](#ignore-overlong-task-comments)

-Whether or not line-length checks (`E501`) should be triggered for
+Whether or not line-length violations (`E501`) should be triggered for
 comments starting with `task-tags` (by default: ["TODO", "FIXME",
 and "XXX"]).

@@ -3057,6 +3176,24 @@ ignore-overlong-task-comments = true

 ---

+#### [`max-doc-length`](#max-doc-length)
+
+The maximum line length to allow for line-length violations within
+documentation (`W505`), including standalone comments.
+
+**Default value**: `None`
+
+**Type**: `usize`
+
+**Example usage**:
+
+```toml
+[tool.ruff.pycodestyle]
+max-doc-length = 88
+```
+
+---
+
 ### `pydocstyle`

 #### [`convention`](#convention)
--- a/assets/badge/v0.json
+++ b/assets/badge/v0.json
@@ -1,8 +1,8 @@
 {
-    "label": "",
-    "message": "Ruff",
-    "logoSvg": "<svg xmlns=\"http://www.w3.org/2000/svg\" width=\"128\" height=\"128\"><path d=\"M115.36 61.84 70.22 50.49 114.45 2.4a1.222 1.222 0 0 0-1.54-1.87L12.3 61.98c-.41.25-.64.72-.57 1.2.06.48.4.87.87 1.01l45.07 13.25-44.29 48.16c-.42.46-.44 1.15-.04 1.61.24.29.58.44.94.44.22 0 .45-.06.65-.19l100.78-63.41c.42-.26.64-.75.56-1.22-.08-.49-.43-.88-.91-.99z\" style=\"fill:#fcc21b\"/></svg>",
-    "logoWidth": 10,
-    "labelColor": "grey",
-    "color": "#E15759"
+  "label": "",
+  "message": "Ruff",
+  "logoSvg": "<svg xmlns=\"http://www.w3.org/2000/svg\" width=\"128\" height=\"128\"><path d=\"M115.36 61.84 70.22 50.49 114.45 2.4a1.222 1.222 0 0 0-1.54-1.87L12.3 61.98c-.41.25-.64.72-.57 1.2.06.48.4.87.87 1.01l45.07 13.25-44.29 48.16c-.42.46-.44 1.15-.04 1.61.24.29.58.44.94.44.22 0 .45-.06.65-.19l100.78-63.41c.42-.26.64-.75.56-1.22-.08-.49-.43-.88-.91-.99z\" style=\"fill:#fcc21b\"/></svg>",
+  "logoWidth": 10,
+  "labelColor": "grey",
+  "color": "#E15759"
 }
--- a/assets/badge/v1.json
+++ b/assets/badge/v1.json
@@ -0,0 +1,8 @@
+{
+  "label": "",
+  "message": "Ruff",
+  "logoSvg": "<svg xmlns=\"http://www.w3.org/2000/svg\" width=\"109\" height=\"132\" fill=\"none\"><g filter=\"url(#a)\"><path fill=\"#FCC21B\" d=\"m103.642 61.492-45.14-11.35 44.23-48.09a1.222 1.222 0 0 0-1.54-1.87L.582 61.632c-.41.25-.64.72-.57 1.2.06.48.4.87.87 1.01l45.07 13.25-44.29 48.16c-.42.46-.44 1.15-.04 1.61.24.29.58.44.94.44.22 0 .45-.06.65-.19l100.78-63.41c.42-.26.64-.75.56-1.22-.08-.49-.43-.88-.91-.99Z\"/></g><defs><filter id=\"a\" width=\"108.569\" height=\"131.302\" x=\"0\" y=\"0\" color-interpolation-filters=\"sRGB\" filterUnits=\"userSpaceOnUse\"><feFlood flood-opacity=\"0\" result=\"BackgroundImageFix\"/><feColorMatrix in=\"SourceAlpha\" result=\"hardAlpha\" values=\"0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 127 0\"/><feOffset dx=\"4\" dy=\"4\"/><feComposite in2=\"hardAlpha\" operator=\"out\"/><feColorMatrix values=\"0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0\"/><feBlend in2=\"BackgroundImageFix\" result=\"effect1_dropShadow_7_4\"/><feBlend in=\"SourceGraphic\" in2=\"effect1_dropShadow_7_4\" result=\"shape\"/></filter></defs></svg>",
+  "logoWidth": 10,
+  "labelColor": "grey",
+  "color": "#E15759"
+}
--- a/flake8_to_ruff/Cargo.lock
+++ b/flake8_to_ruff/Cargo.lock
@@ -771,7 +771,7 @@ checksum = "0ce7134b9999ecaf8bcd65542e436736ef32ddca1b3e06094cb6ec5755203b80"

 [[package]]
 name = "flake8_to_ruff"
-version = "0.0.211"
+version = "0.0.219"
 dependencies = [
 "anyhow",
 "clap",
@@ -1975,7 +1975,7 @@ dependencies = [

 [[package]]
 name = "ruff"
-version = "0.0.211"
+version = "0.0.219"
 dependencies = [
 "anyhow",
 "bincode",
--- a/flake8_to_ruff/Cargo.toml
+++ b/flake8_to_ruff/Cargo.toml
@@ -1,14 +1,16 @@
 [package]
 name = "flake8-to-ruff"
-version = "0.0.211-dev.0"
+version = "0.0.219-dev.0"
 edition = "2021"

 [lib]
 name = "flake8_to_ruff"
+doctest = false

 [dependencies]
 anyhow = { version = "1.0.66" }
 clap = { version = "4.0.1", features = ["derive"] }
+colored = { version = "2.0.0" }
 configparser = { version = "3.0.2" }
 once_cell = { version = "1.16.0" }
 regex = { version = "1.6.0" }
@@ -18,7 +20,7 @@ serde = { version = "1.0.147", features = ["derive"] }
 serde_json = { version = "1.0.87" }
 strum = { version = "0.24.1", features = ["strum_macros"] }
 strum_macros = { version = "0.24.3" }
-toml = { version = "0.5.9" }
+toml_edit = { version = "0.17.1", features = ["easy"] }

 [dev-dependencies]

--- a/flake8_to_ruff/README.md
+++ b/flake8_to_ruff/README.md
@@ -84,7 +84,7 @@ flake8-to-ruff path/to/.flake8 --plugin flake8-builtins --plugin flake8-quotes
 1. Ruff only supports a subset of the Flake configuration options. `flake8-to-ruff` will warn on and
   ignore unsupported options in the `.flake8` file (or equivalent). (Similarly, Ruff has a few
   configuration options that don't exist in Flake8.)
-2. Ruff will omit any error codes that are unimplemented or unsupported by Ruff, including error
+2. Ruff will omit any rule codes that are unimplemented or unsupported by Ruff, including rule
   codes from unsupported plugins. (See the [Ruff README](https://github.com/charliermarsh/ruff#user-content-how-does-ruff-compare-to-flake8)
   for the complete list of supported plugins.)

--- a/flake8_to_ruff/examples/jupyterhub.ini
+++ b/flake8_to_ruff/examples/jupyterhub.ini
@@ -0,0 +1,19 @@
+[flake8]
+# Ignore style and complexity
+# E: style errors
+# W: style warnings
+# C: complexity
+# D: docstring warnings (unused pydocstyle extension)
+# F841: local variable assigned but never used
+ignore = E, C, W, D, F841
+builtins = c, get_config
+exclude =
+    .cache,
+    .github,
+    docs,
+    jupyterhub/alembic*,
+    onbuild,
+    scripts,
+    share,
+    tools,
+    setup.py
--- a/flake8_to_ruff/src/black.rs
+++ b/flake8_to_ruff/src/black.rs
@@ -26,7 +26,7 @@ struct Pyproject {

 pub fn parse_black_options<P: AsRef<Path>>(path: P) -> Result<Option<Black>> {
    let contents = std::fs::read_to_string(path)?;
-    Ok(toml::from_str::<Pyproject>(&contents)?
+    Ok(toml_edit::easy::from_str::<Pyproject>(&contents)?
        .tool
        .and_then(|tool| tool.black))
 }
--- a/flake8_to_ruff/src/converter.rs
+++ b/flake8_to_ruff/src/converter.rs
@@ -1,18 +1,19 @@
 use std::collections::{BTreeSet, HashMap};

 use anyhow::Result;
+use colored::Colorize;
 use ruff::flake8_pytest_style::types::{
    ParametrizeNameType, ParametrizeValuesRowType, ParametrizeValuesType,
 };
 use ruff::flake8_quotes::settings::Quote;
 use ruff::flake8_tidy_imports::settings::Strictness;
 use ruff::pydocstyle::settings::Convention;
-use ruff::registry_gen::CheckCodePrefix;
+use ruff::registry::RuleCodePrefix;
 use ruff::settings::options::Options;
 use ruff::settings::pyproject::Pyproject;
 use ruff::{
    flake8_annotations, flake8_bugbear, flake8_errmsg, flake8_pytest_style, flake8_quotes,
-    flake8_tidy_imports, mccabe, pep8_naming, pydocstyle,
+    flake8_tidy_imports, mccabe, pep8_naming, pydocstyle, warn_user,
 };

 use crate::black::Black;
@@ -29,8 +30,8 @@ pub fn convert(
        .get("flake8")
        .expect("Unable to find flake8 section in INI file");

-    // Extract all referenced check code prefixes, to power plugin inference.
-    let mut referenced_codes: BTreeSet<CheckCodePrefix> = BTreeSet::default();
+    // Extract all referenced rule code prefixes, to power plugin inference.
+    let mut referenced_codes: BTreeSet<RuleCodePrefix> = BTreeSet::default();
    for (key, value) in flake8 {
        if let Some(value) = value {
            match key.as_str() {
@@ -60,7 +61,7 @@ pub fn convert(
        }
        let from_codes = plugin::infer_plugins_from_codes(&referenced_codes);
        if !from_codes.is_empty() {
-            eprintln!("Inferred plugins from referenced check codes: {from_codes:#?}");
+            eprintln!("Inferred plugins from referenced codes: {from_codes:#?}");
        }
        from_options.into_iter().chain(from_codes).collect()
    });
@@ -99,9 +100,14 @@ pub fn convert(
        if let Some(value) = value {
            match key.as_str() {
                // flake8
+                "builtins" => {
+                    options.builtins = Some(parser::parse_strings(value.as_ref()));
+                }
                "max-line-length" | "max_line_length" => match value.clone().parse::<usize>() {
                    Ok(line_length) => options.line_length = Some(line_length),
-                    Err(e) => eprintln!("Unable to parse '{key}' property: {e}"),
+                    Err(e) => {
+                        warn_user!("Unable to parse '{key}' property: {e}");
+                    }
                },
                "select" => {
                    // No-op (handled above).
@@ -130,7 +136,9 @@ pub fn convert(
                            options.per_file_ignores =
                                Some(parser::collect_per_file_ignores(per_file_ignores));
                        }
-                        Err(e) => eprintln!("Unable to parse '{key}' property: {e}"),
+                        Err(e) => {
+                            warn_user!("Unable to parse '{key}' property: {e}");
+                        }
                    }
                }
                // flake8-bugbear
@@ -142,46 +150,62 @@ pub fn convert(
                "suppress-none-returning" | "suppress_none_returning" => {
                    match parser::parse_bool(value.as_ref()) {
                        Ok(bool) => flake8_annotations.suppress_none_returning = Some(bool),
-                        Err(e) => eprintln!("Unable to parse '{key}' property: {e}"),
+                        Err(e) => {
+                            warn_user!("Unable to parse '{key}' property: {e}");
+                        }
                    }
                }
                "suppress-dummy-args" | "suppress_dummy_args" => {
                    match parser::parse_bool(value.as_ref()) {
                        Ok(bool) => flake8_annotations.suppress_dummy_args = Some(bool),
-                        Err(e) => eprintln!("Unable to parse '{key}' property: {e}"),
+                        Err(e) => {
+                            warn_user!("Unable to parse '{key}' property: {e}");
+                        }
                    }
                }
                "mypy-init-return" | "mypy_init_return" => {
                    match parser::parse_bool(value.as_ref()) {
                        Ok(bool) => flake8_annotations.mypy_init_return = Some(bool),
-                        Err(e) => eprintln!("Unable to parse '{key}' property: {e}"),
+                        Err(e) => {
+                            warn_user!("Unable to parse '{key}' property: {e}");
+                        }
                    }
                }
                "allow-star-arg-any" | "allow_star_arg_any" => {
                    match parser::parse_bool(value.as_ref()) {
                        Ok(bool) => flake8_annotations.allow_star_arg_any = Some(bool),
-                        Err(e) => eprintln!("Unable to parse '{key}' property: {e}"),
+                        Err(e) => {
+                            warn_user!("Unable to parse '{key}' property: {e}");
+                        }
                    }
                }
                // flake8-quotes
                "quotes" | "inline-quotes" | "inline_quotes" => match value.trim() {
                    "'" | "single" => flake8_quotes.inline_quotes = Some(Quote::Single),
                    "\"" | "double" => flake8_quotes.inline_quotes = Some(Quote::Double),
-                    _ => eprintln!("Unexpected '{key}' value: {value}"),
+                    _ => {
+                        warn_user!("Unexpected '{key}' value: {value}");
+                    }
                },
                "multiline-quotes" | "multiline_quotes" => match value.trim() {
                    "'" | "single" => flake8_quotes.multiline_quotes = Some(Quote::Single),
                    "\"" | "double" => flake8_quotes.multiline_quotes = Some(Quote::Double),
-                    _ => eprintln!("Unexpected '{key}' value: {value}"),
+                    _ => {
+                        warn_user!("Unexpected '{key}' value: {value}");
+                    }
                },
                "docstring-quotes" | "docstring_quotes" => match value.trim() {
                    "'" | "single" => flake8_quotes.docstring_quotes = Some(Quote::Single),
                    "\"" | "double" => flake8_quotes.docstring_quotes = Some(Quote::Double),
-                    _ => eprintln!("Unexpected '{key}' value: {value}"),
+                    _ => {
+                        warn_user!("Unexpected '{key}' value: {value}");
+                    }
                },
                "avoid-escape" | "avoid_escape" => match parser::parse_bool(value.as_ref()) {
                    Ok(bool) => flake8_quotes.avoid_escape = Some(bool),
-                    Err(e) => eprintln!("Unable to parse '{key}' property: {e}"),
+                    Err(e) => {
+                        warn_user!("Unable to parse '{key}' property: {e}");
+                    }
                },
                // pep8-naming
                "ignore-names" | "ignore_names" => {
@@ -201,7 +225,9 @@ pub fn convert(
                    "parents" => {
                        flake8_tidy_imports.ban_relative_imports = Some(Strictness::Parents);
                    }
-                    _ => eprintln!("Unexpected '{key}' value: {value}"),
+                    _ => {
+                        warn_user!("Unexpected '{key}' value: {value}");
+                    }
                },
                // flake8-docstrings
                "docstring-convention" => match value.trim() {
@@ -209,12 +235,16 @@ pub fn convert(
                    "numpy" => pydocstyle.convention = Some(Convention::Numpy),
                    "pep257" => pydocstyle.convention = Some(Convention::Pep257),
                    "all" => pydocstyle.convention = None,
-                    _ => eprintln!("Unexpected '{key}' value: {value}"),
+                    _ => {
+                        warn_user!("Unexpected '{key}' value: {value}");
+                    }
                },
                // mccabe
                "max-complexity" | "max_complexity" => match value.clone().parse::<usize>() {
                    Ok(max_complexity) => mccabe.max_complexity = Some(max_complexity),
-                    Err(e) => eprintln!("Unable to parse '{key}' property: {e}"),
+                    Err(e) => {
+                        warn_user!("Unable to parse '{key}' property: {e}");
+                    }
                },
                // flake8-errmsg
                "errmsg-max-string-length" | "errmsg_max_string_length" => {
@@ -222,14 +252,18 @@ pub fn convert(
                        Ok(max_string_length) => {
                            flake8_errmsg.max_string_length = Some(max_string_length);
                        }
-                        Err(e) => eprintln!("Unable to parse '{key}' property: {e}"),
+                        Err(e) => {
+                            warn_user!("Unable to parse '{key}' property: {e}");
+                        }
                    }
                }
                // flake8-pytest-style
                "pytest-fixture-no-parentheses" | "pytest_fixture_no_parentheses " => {
                    match parser::parse_bool(value.as_ref()) {
                        Ok(bool) => flake8_pytest_style.fixture_parentheses = Some(!bool),
-                        Err(e) => eprintln!("Unable to parse '{key}' property: {e}"),
+                        Err(e) => {
+                            warn_user!("Unable to parse '{key}' property: {e}");
+                        }
                    }
                }
                "pytest-parametrize-names-type" | "pytest_parametrize_names_type" => {
@@ -246,7 +280,9 @@ pub fn convert(
                            flake8_pytest_style.parametrize_names_type =
                                Some(ParametrizeNameType::List);
                        }
-                        _ => eprintln!("Unexpected '{key}' value: {value}"),
+                        _ => {
+                            warn_user!("Unexpected '{key}' value: {value}");
+                        }
                    }
                }
                "pytest-parametrize-values-type" | "pytest_parametrize_values_type" => {
@@ -259,7 +295,9 @@ pub fn convert(
                            flake8_pytest_style.parametrize_values_type =
                                Some(ParametrizeValuesType::List);
                        }
-                        _ => eprintln!("Unexpected '{key}' value: {value}"),
+                        _ => {
+                            warn_user!("Unexpected '{key}' value: {value}");
+                        }
                    }
                }
                "pytest-parametrize-values-row-type" | "pytest_parametrize_values_row_type" => {
@@ -272,7 +310,9 @@ pub fn convert(
                            flake8_pytest_style.parametrize_values_row_type =
                                Some(ParametrizeValuesRowType::List);
                        }
-                        _ => eprintln!("Unexpected '{key}' value: {value}"),
+                        _ => {
+                            warn_user!("Unexpected '{key}' value: {value}");
+                        }
                    }
                }
                "pytest-raises-require-match-for" | "pytest_raises_require_match_for" => {
@@ -282,11 +322,15 @@ pub fn convert(
                "pytest-mark-no-parentheses" | "pytest_mark_no_parentheses" => {
                    match parser::parse_bool(value.as_ref()) {
                        Ok(bool) => flake8_pytest_style.mark_parentheses = Some(!bool),
-                        Err(e) => eprintln!("Unable to parse '{key}' property: {e}"),
+                        Err(e) => {
+                            warn_user!("Unable to parse '{key}' property: {e}");
+                        }
                    }
                }
                // Unknown
-                _ => eprintln!("Skipping unsupported property: {key}"),
+                _ => {
+                    warn_user!("Skipping unsupported property: {}", key);
+                }
            }
        }
    }
@@ -345,7 +389,7 @@ mod tests {

    use anyhow::Result;
    use ruff::pydocstyle::settings::Convention;
-    use ruff::registry_gen::CheckCodePrefix;
+    use ruff::registry::RuleCodePrefix;
    use ruff::settings::options::Options;
    use ruff::settings::pyproject::Pyproject;
    use ruff::{flake8_quotes, pydocstyle};
@@ -362,6 +406,7 @@ mod tests {
        )?;
        let expected = Pyproject::new(Options {
            allowed_confusables: None,
+            builtins: None,
            cache_dir: None,
            dummy_variable_rgx: None,
            exclude: None,
@@ -382,14 +427,15 @@ mod tests {
            required_version: None,
            respect_gitignore: None,
            select: Some(vec![
-                CheckCodePrefix::E,
-                CheckCodePrefix::F,
-                CheckCodePrefix::W,
+                RuleCodePrefix::E,
+                RuleCodePrefix::F,
+                RuleCodePrefix::W,
            ]),
            show_source: None,
            src: None,
            target_version: None,
            unfixable: None,
+            typing_modules: None,
            task_tags: None,
            update_check: None,
            flake8_annotations: None,
@@ -425,6 +471,7 @@ mod tests {
        )?;
        let expected = Pyproject::new(Options {
            allowed_confusables: None,
+            builtins: None,
            cache_dir: None,
            dummy_variable_rgx: None,
            exclude: None,
@@ -445,14 +492,15 @@ mod tests {
            required_version: None,
            respect_gitignore: None,
            select: Some(vec![
-                CheckCodePrefix::E,
-                CheckCodePrefix::F,
-                CheckCodePrefix::W,
+                RuleCodePrefix::E,
+                RuleCodePrefix::F,
+                RuleCodePrefix::W,
            ]),
            show_source: None,
            src: None,
            target_version: None,
            unfixable: None,
+            typing_modules: None,
            task_tags: None,
            update_check: None,
            flake8_annotations: None,
@@ -488,6 +536,7 @@ mod tests {
        )?;
        let expected = Pyproject::new(Options {
            allowed_confusables: None,
+            builtins: None,
            cache_dir: None,
            dummy_variable_rgx: None,
            exclude: None,
@@ -508,14 +557,15 @@ mod tests {
            required_version: None,
            respect_gitignore: None,
            select: Some(vec![
-                CheckCodePrefix::E,
-                CheckCodePrefix::F,
-                CheckCodePrefix::W,
+                RuleCodePrefix::E,
+                RuleCodePrefix::F,
+                RuleCodePrefix::W,
            ]),
            show_source: None,
            src: None,
            target_version: None,
            unfixable: None,
+            typing_modules: None,
            task_tags: None,
            update_check: None,
            flake8_annotations: None,
@@ -551,6 +601,7 @@ mod tests {
        )?;
        let expected = Pyproject::new(Options {
            allowed_confusables: None,
+            builtins: None,
            cache_dir: None,
            dummy_variable_rgx: None,
            exclude: None,
@@ -571,14 +622,15 @@ mod tests {
            required_version: None,
            respect_gitignore: None,
            select: Some(vec![
-                CheckCodePrefix::E,
-                CheckCodePrefix::F,
-                CheckCodePrefix::W,
+                RuleCodePrefix::E,
+                RuleCodePrefix::F,
+                RuleCodePrefix::W,
            ]),
            show_source: None,
            src: None,
            target_version: None,
            unfixable: None,
+            typing_modules: None,
            task_tags: None,
            update_check: None,
            flake8_annotations: None,
@@ -614,6 +666,7 @@ mod tests {
        )?;
        let expected = Pyproject::new(Options {
            allowed_confusables: None,
+            builtins: None,
            cache_dir: None,
            dummy_variable_rgx: None,
            exclude: None,
@@ -634,14 +687,15 @@ mod tests {
            required_version: None,
            respect_gitignore: None,
            select: Some(vec![
-                CheckCodePrefix::E,
-                CheckCodePrefix::F,
-                CheckCodePrefix::W,
+                RuleCodePrefix::E,
+                RuleCodePrefix::F,
+                RuleCodePrefix::W,
            ]),
            show_source: None,
            src: None,
            target_version: None,
            unfixable: None,
+            typing_modules: None,
            task_tags: None,
            update_check: None,
            flake8_annotations: None,
@@ -685,6 +739,7 @@ mod tests {
        )?;
        let expected = Pyproject::new(Options {
            allowed_confusables: None,
+            builtins: None,
            cache_dir: None,
            dummy_variable_rgx: None,
            exclude: None,
@@ -705,15 +760,16 @@ mod tests {
            required_version: None,
            respect_gitignore: None,
            select: Some(vec![
-                CheckCodePrefix::D,
-                CheckCodePrefix::E,
-                CheckCodePrefix::F,
-                CheckCodePrefix::W,
+                RuleCodePrefix::D,
+                RuleCodePrefix::E,
+                RuleCodePrefix::F,
+                RuleCodePrefix::W,
            ]),
            show_source: None,
            src: None,
            target_version: None,
            unfixable: None,
+            typing_modules: None,
            task_tags: None,
            update_check: None,
            flake8_annotations: None,
@@ -751,6 +807,7 @@ mod tests {
        )?;
        let expected = Pyproject::new(Options {
            allowed_confusables: None,
+            builtins: None,
            cache_dir: None,
            dummy_variable_rgx: None,
            exclude: None,
@@ -771,15 +828,16 @@ mod tests {
            required_version: None,
            respect_gitignore: None,
            select: Some(vec![
-                CheckCodePrefix::E,
-                CheckCodePrefix::F,
-                CheckCodePrefix::Q,
-                CheckCodePrefix::W,
+                RuleCodePrefix::E,
+                RuleCodePrefix::F,
+                RuleCodePrefix::Q,
+                RuleCodePrefix::W,
            ]),
            show_source: None,
            src: None,
            target_version: None,
            unfixable: None,
+            typing_modules: None,
            task_tags: None,
            update_check: None,
            flake8_annotations: None,
--- a/flake8_to_ruff/src/lib.rs
+++ b/flake8_to_ruff/src/lib.rs
@@ -10,6 +10,7 @@
    clippy::similar_names,
    clippy::too_many_lines
 )]
+#![forbid(unsafe_code)]

 pub mod black;
 pub mod converter;
--- a/flake8_to_ruff/src/main.rs
+++ b/flake8_to_ruff/src/main.rs
@@ -11,6 +11,7 @@
    clippy::similar_names,
    clippy::too_many_lines
 )]
+#![forbid(unsafe_code)]

 use std::path::PathBuf;

@@ -57,7 +58,7 @@ fn main() -> Result<()> {

    // Create Ruff's pyproject.toml section.
    let pyproject = converter::convert(&config, black.as_ref(), cli.plugin)?;
-    println!("{}", toml::to_string_pretty(&pyproject)?);
+    println!("{}", toml_edit::easy::to_string_pretty(&pyproject)?);

    Ok(())
 }
--- a/flake8_to_ruff/src/parser.rs
+++ b/flake8_to_ruff/src/parser.rs
@@ -1,19 +1,20 @@
 use std::str::FromStr;

 use anyhow::{bail, Result};
+use colored::Colorize;
 use once_cell::sync::Lazy;
 use regex::Regex;
-use ruff::registry::PREFIX_REDIRECTS;
-use ruff::registry_gen::CheckCodePrefix;
+use ruff::registry::{RuleCodePrefix, PREFIX_REDIRECTS};
 use ruff::settings::types::PatternPrefixPair;
+use ruff::warn_user;
 use rustc_hash::FxHashMap;

 static COMMA_SEPARATED_LIST_RE: Lazy<Regex> = Lazy::new(|| Regex::new(r"[,\s]").unwrap());

-/// Parse a comma-separated list of `CheckCodePrefix` values (e.g.,
+/// Parse a comma-separated list of `RuleCodePrefix` values (e.g.,
 /// "F401,E501").
-pub fn parse_prefix_codes(value: &str) -> Vec<CheckCodePrefix> {
-    let mut codes: Vec<CheckCodePrefix> = vec![];
+pub fn parse_prefix_codes(value: &str) -> Vec<RuleCodePrefix> {
+    let mut codes: Vec<RuleCodePrefix> = vec![];
    for code in COMMA_SEPARATED_LIST_RE.split(value) {
        let code = code.trim();
        if code.is_empty() {
@@ -21,10 +22,10 @@ pub fn parse_prefix_codes(value: &str) -> Vec<CheckCodePrefix> {
        }
        if let Some(code) = PREFIX_REDIRECTS.get(code) {
            codes.push(code.clone());
-        } else if let Ok(code) = CheckCodePrefix::from_str(code) {
+        } else if let Ok(code) = RuleCodePrefix::from_str(code) {
            codes.push(code);
        } else {
-            eprintln!("Unsupported prefix code: {code}");
+            warn_user!("Unsupported prefix code: {code}");
        }
    }
    codes
@@ -82,7 +83,8 @@ impl State {
        }
    }

-    /// Generate the list of `StrCheckCodePair` pairs for the current state.
+    /// Generate the list of `StrRuleCodePair` pairs for the current
+    /// state.
    fn parse(&self) -> Vec<PatternPrefixPair> {
        let mut codes: Vec<PatternPrefixPair> = vec![];
        for code in &self.codes {
@@ -93,7 +95,7 @@ impl State {
                        prefix: code.clone(),
                    });
                }
-            } else if let Ok(code) = CheckCodePrefix::from_str(code) {
+            } else if let Ok(code) = RuleCodePrefix::from_str(code) {
                for filename in &self.filenames {
                    codes.push(PatternPrefixPair {
                        pattern: filename.clone(),
@@ -101,7 +103,7 @@ impl State {
                    });
                }
            } else {
-                eprintln!("Unsupported prefix code: {code}");
+                warn_user!("Unsupported prefix code: {code}");
            }
        }
        codes
@@ -128,7 +130,7 @@ fn tokenize_files_to_codes_mapping(value: &str) -> Vec<Token> {
                if mat.start() == 0 {
                    tokens.push(Token {
                        token_name,
-                        src: mat.as_str().to_string().trim().to_string(),
+                        src: mat.as_str().trim().to_string(),
                    });
                    i += mat.end();
                    break;
@@ -187,8 +189,8 @@ pub fn parse_files_to_codes_mapping(value: &str) -> Result<Vec<PatternPrefixPair
 /// Collect a list of `PatternPrefixPair` structs as a `BTreeMap`.
 pub fn collect_per_file_ignores(
    pairs: Vec<PatternPrefixPair>,
-) -> FxHashMap<String, Vec<CheckCodePrefix>> {
-    let mut per_file_ignores: FxHashMap<String, Vec<CheckCodePrefix>> = FxHashMap::default();
+) -> FxHashMap<String, Vec<RuleCodePrefix>> {
+    let mut per_file_ignores: FxHashMap<String, Vec<RuleCodePrefix>> = FxHashMap::default();
    for pair in pairs {
        per_file_ignores
            .entry(pair.pattern)
@@ -201,7 +203,7 @@ pub fn collect_per_file_ignores(
 #[cfg(test)]
 mod tests {
    use anyhow::Result;
-    use ruff::registry_gen::CheckCodePrefix;
+    use ruff::registry::RuleCodePrefix;
    use ruff::settings::types::PatternPrefixPair;

    use crate::parser::{parse_files_to_codes_mapping, parse_prefix_codes, parse_strings};
@@ -209,27 +211,27 @@ mod tests {
    #[test]
    fn it_parses_prefix_codes() {
        let actual = parse_prefix_codes("");
-        let expected: Vec<CheckCodePrefix> = vec![];
+        let expected: Vec<RuleCodePrefix> = vec![];
        assert_eq!(actual, expected);

        let actual = parse_prefix_codes(" ");
-        let expected: Vec<CheckCodePrefix> = vec![];
+        let expected: Vec<RuleCodePrefix> = vec![];
        assert_eq!(actual, expected);

        let actual = parse_prefix_codes("F401");
-        let expected = vec![CheckCodePrefix::F401];
+        let expected = vec![RuleCodePrefix::F401];
        assert_eq!(actual, expected);

        let actual = parse_prefix_codes("F401,");
-        let expected = vec![CheckCodePrefix::F401];
+        let expected = vec![RuleCodePrefix::F401];
        assert_eq!(actual, expected);

        let actual = parse_prefix_codes("F401,E501");
-        let expected = vec![CheckCodePrefix::F401, CheckCodePrefix::E501];
+        let expected = vec![RuleCodePrefix::F401, RuleCodePrefix::E501];
        assert_eq!(actual, expected);

        let actual = parse_prefix_codes("F401, E501");
-        let expected = vec![CheckCodePrefix::F401, CheckCodePrefix::E501];
+        let expected = vec![RuleCodePrefix::F401, RuleCodePrefix::E501];
        assert_eq!(actual, expected);
    }

@@ -282,11 +284,11 @@ mod tests {
        let expected: Vec<PatternPrefixPair> = vec![
            PatternPrefixPair {
                pattern: "locust/test/*".to_string(),
-                prefix: CheckCodePrefix::F841,
+                prefix: RuleCodePrefix::F841,
            },
            PatternPrefixPair {
                pattern: "examples/*".to_string(),
-                prefix: CheckCodePrefix::F841,
+                prefix: RuleCodePrefix::F841,
            },
        ];
        assert_eq!(actual, expected);
@@ -302,23 +304,23 @@ mod tests {
        let expected: Vec<PatternPrefixPair> = vec![
            PatternPrefixPair {
                pattern: "t/*".to_string(),
-                prefix: CheckCodePrefix::D,
+                prefix: RuleCodePrefix::D,
            },
            PatternPrefixPair {
                pattern: "setup.py".to_string(),
-                prefix: CheckCodePrefix::D,
+                prefix: RuleCodePrefix::D,
            },
            PatternPrefixPair {
                pattern: "examples/*".to_string(),
-                prefix: CheckCodePrefix::D,
+                prefix: RuleCodePrefix::D,
            },
            PatternPrefixPair {
                pattern: "docs/*".to_string(),
-                prefix: CheckCodePrefix::D,
+                prefix: RuleCodePrefix::D,
            },
            PatternPrefixPair {
                pattern: "extra/*".to_string(),
-                prefix: CheckCodePrefix::D,
+                prefix: RuleCodePrefix::D,
            },
        ];
        assert_eq!(actual, expected);
@@ -340,47 +342,47 @@ mod tests {
        let expected: Vec<PatternPrefixPair> = vec![
            PatternPrefixPair {
                pattern: "scrapy/__init__.py".to_string(),
-                prefix: CheckCodePrefix::E402,
+                prefix: RuleCodePrefix::E402,
            },
            PatternPrefixPair {
                pattern: "scrapy/core/downloader/handlers/http.py".to_string(),
-                prefix: CheckCodePrefix::F401,
+                prefix: RuleCodePrefix::F401,
            },
            PatternPrefixPair {
                pattern: "scrapy/http/__init__.py".to_string(),
-                prefix: CheckCodePrefix::F401,
+                prefix: RuleCodePrefix::F401,
            },
            PatternPrefixPair {
                pattern: "scrapy/linkextractors/__init__.py".to_string(),
-                prefix: CheckCodePrefix::E402,
+                prefix: RuleCodePrefix::E402,
            },
            PatternPrefixPair {
                pattern: "scrapy/linkextractors/__init__.py".to_string(),
-                prefix: CheckCodePrefix::F401,
+                prefix: RuleCodePrefix::F401,
            },
            PatternPrefixPair {
                pattern: "scrapy/selector/__init__.py".to_string(),
-                prefix: CheckCodePrefix::F401,
+                prefix: RuleCodePrefix::F401,
            },
            PatternPrefixPair {
                pattern: "scrapy/spiders/__init__.py".to_string(),
-                prefix: CheckCodePrefix::E402,
+                prefix: RuleCodePrefix::E402,
            },
            PatternPrefixPair {
                pattern: "scrapy/spiders/__init__.py".to_string(),
-                prefix: CheckCodePrefix::F401,
+                prefix: RuleCodePrefix::F401,
            },
            PatternPrefixPair {
                pattern: "scrapy/utils/url.py".to_string(),
-                prefix: CheckCodePrefix::F403,
+                prefix: RuleCodePrefix::F403,
            },
            PatternPrefixPair {
                pattern: "scrapy/utils/url.py".to_string(),
-                prefix: CheckCodePrefix::F405,
+                prefix: RuleCodePrefix::F405,
            },
            PatternPrefixPair {
                pattern: "tests/test_loader.py".to_string(),
-                prefix: CheckCodePrefix::E741,
+                prefix: RuleCodePrefix::E741,
            },
        ];
        assert_eq!(actual, expected);
--- a/flake8_to_ruff/src/plugin.rs
+++ b/flake8_to_ruff/src/plugin.rs
@@ -3,7 +3,7 @@ use std::fmt;
 use std::str::FromStr;

 use anyhow::anyhow;
-use ruff::registry_gen::CheckCodePrefix;
+use ruff::registry::RuleCodePrefix;

 #[derive(Clone, Ord, PartialOrd, Eq, PartialEq)]
 pub enum Plugin {
@@ -97,53 +97,32 @@ impl fmt::Debug for Plugin {
 }

 impl Plugin {
-    pub fn prefix(&self) -> CheckCodePrefix {
+    pub fn prefix(&self) -> RuleCodePrefix {
        match self {
-            Plugin::Flake8Annotations => CheckCodePrefix::ANN,
-            Plugin::Flake8Bandit => CheckCodePrefix::S,
+            Plugin::Flake8Annotations => RuleCodePrefix::ANN,
+            Plugin::Flake8Bandit => RuleCodePrefix::S,
            // TODO(charlie): Handle rename of `B` to `BLE`.
-            Plugin::Flake8BlindExcept => CheckCodePrefix::BLE,
-            Plugin::Flake8Bugbear => CheckCodePrefix::B,
-            Plugin::Flake8Builtins => CheckCodePrefix::A,
-            Plugin::Flake8Comprehensions => CheckCodePrefix::C4,
-            Plugin::Flake8Datetimez => CheckCodePrefix::DTZ,
-            Plugin::Flake8Debugger => CheckCodePrefix::T1,
-            Plugin::Flake8Docstrings => CheckCodePrefix::D,
+            Plugin::Flake8BlindExcept => RuleCodePrefix::BLE,
+            Plugin::Flake8Bugbear => RuleCodePrefix::B,
+            Plugin::Flake8Builtins => RuleCodePrefix::A,
+            Plugin::Flake8Comprehensions => RuleCodePrefix::C4,
+            Plugin::Flake8Datetimez => RuleCodePrefix::DTZ,
+            Plugin::Flake8Debugger => RuleCodePrefix::T1,
+            Plugin::Flake8Docstrings => RuleCodePrefix::D,
            // TODO(charlie): Handle rename of `E` to `ERA`.
-            Plugin::Flake8Eradicate => CheckCodePrefix::ERA,
-            Plugin::Flake8ErrMsg => CheckCodePrefix::EM,
-            Plugin::Flake8ImplicitStrConcat => CheckCodePrefix::ISC,
-            Plugin::Flake8Print => CheckCodePrefix::T2,
-            Plugin::Flake8PytestStyle => CheckCodePrefix::PT,
-            Plugin::Flake8Quotes => CheckCodePrefix::Q,
-            Plugin::Flake8Return => CheckCodePrefix::RET,
-            Plugin::Flake8Simplify => CheckCodePrefix::SIM,
-            Plugin::Flake8TidyImports => CheckCodePrefix::TID25,
-            Plugin::McCabe => CheckCodePrefix::C9,
-            Plugin::PandasVet => CheckCodePrefix::PD,
-            Plugin::PEP8Naming => CheckCodePrefix::N,
-            Plugin::Pyupgrade => CheckCodePrefix::UP,
-        }
-    }
-}
-
-pub enum DocstringConvention {
-    All,
-    Pep257,
-    Numpy,
-    Google,
-}
-
-impl FromStr for DocstringConvention {
-    type Err = anyhow::Error;
-
-    fn from_str(string: &str) -> Result<Self, Self::Err> {
-        match string {
-            "all" => Ok(DocstringConvention::All),
-            "pep257" => Ok(DocstringConvention::Pep257),
-            "numpy" => Ok(DocstringConvention::Numpy),
-            "google" => Ok(DocstringConvention::Google),
-            _ => Err(anyhow!("Unknown docstring convention: {string}")),
+            Plugin::Flake8Eradicate => RuleCodePrefix::ERA,
+            Plugin::Flake8ErrMsg => RuleCodePrefix::EM,
+            Plugin::Flake8ImplicitStrConcat => RuleCodePrefix::ISC,
+            Plugin::Flake8Print => RuleCodePrefix::T2,
+            Plugin::Flake8PytestStyle => RuleCodePrefix::PT,
+            Plugin::Flake8Quotes => RuleCodePrefix::Q,
+            Plugin::Flake8Return => RuleCodePrefix::RET,
+            Plugin::Flake8Simplify => RuleCodePrefix::SIM,
+            Plugin::Flake8TidyImports => RuleCodePrefix::TID25,
+            Plugin::McCabe => RuleCodePrefix::C9,
+            Plugin::PandasVet => RuleCodePrefix::PD,
+            Plugin::PEP8Naming => RuleCodePrefix::N,
+            Plugin::Pyupgrade => RuleCodePrefix::UP,
        }
    }
 }
@@ -269,7 +248,7 @@ pub fn infer_plugins_from_options(flake8: &HashMap<String, Option<String>>) -> V
 ///
 /// For example, if the user ignores `ANN101`, we should infer that
 /// `flake8-annotations` is active.
-pub fn infer_plugins_from_codes(codes: &BTreeSet<CheckCodePrefix>) -> Vec<Plugin> {
+pub fn infer_plugins_from_codes(codes: &BTreeSet<RuleCodePrefix>) -> Vec<Plugin> {
    [
        Plugin::Flake8Annotations,
        Plugin::Flake8Bandit,
@@ -307,9 +286,10 @@ pub fn infer_plugins_from_codes(codes: &BTreeSet<CheckCodePrefix>) -> Vec<Plugin
    .collect()
 }

-/// Resolve the set of enabled `CheckCodePrefix` values for the given plugins.
-pub fn resolve_select(plugins: &[Plugin]) -> BTreeSet<CheckCodePrefix> {
-    let mut select = BTreeSet::from([CheckCodePrefix::F, CheckCodePrefix::E, CheckCodePrefix::W]);
+/// Resolve the set of enabled `RuleCodePrefix` values for the given
+/// plugins.
+pub fn resolve_select(plugins: &[Plugin]) -> BTreeSet<RuleCodePrefix> {
+    let mut select = BTreeSet::from([RuleCodePrefix::F, RuleCodePrefix::E, RuleCodePrefix::W]);
    select.extend(plugins.iter().map(Plugin::prefix));
    select
 }
--- a/playground/src/Editor/Editor.tsx
+++ b/playground/src/Editor/Editor.tsx
@@ -1,6 +1,11 @@
 import { useCallback, useEffect, useState } from "react";
 import { DEFAULT_PYTHON_SOURCE } from "../constants";
-import init, { check, Check, currentVersion, defaultSettings } from "../pkg";
+import init, {
+  check,
+  Diagnostic,
+  currentVersion,
+  defaultSettings,
+} from "../pkg";
 import { ErrorMessage } from "./ErrorMessage";
 import Header from "./Header";
 import { useTheme } from "./theme";
@@ -18,7 +23,7 @@ export default function Editor() {
  const [edit, setEdit] = useState<number>(0);
  const [settingsSource, setSettingsSource] = useState<string | null>(null);
  const [pythonSource, setPythonSource] = useState<string | null>(null);
-  const [checks, setChecks] = useState<Check[]>([]);
+  const [diagnostics, setDiagnostics] = useState<Diagnostic[]>([]);
  const [error, setError] = useState<string | null>(null);
  const [theme, setTheme] = useTheme();

@@ -32,25 +37,25 @@ export default function Editor() {
    }

    let config: any;
-    let checks: Check[];
+    let diagnostics: Diagnostic[];

    try {
      config = JSON.parse(settingsSource);
    } catch (e) {
-      setChecks([]);
+      setDiagnostics([]);
      setError((e as Error).message);
      return;
    }

    try {
-      checks = check(pythonSource, config);
+      diagnostics = check(pythonSource, config);
    } catch (e) {
      setError(e as string);
      return;
    }

    setError(null);
-    setChecks(checks);
+    setDiagnostics(diagnostics);
  }, [initialized, settingsSource, pythonSource]);

  useEffect(() => {
@@ -122,7 +127,7 @@ export default function Editor() {
              visible={tab === "Source"}
              source={pythonSource}
              theme={theme}
-              checks={checks}
+              diagnostics={diagnostics}
              onChange={handlePythonSourceChange}
            />
            <SettingsEditor
--- a/playground/src/Editor/SourceEditor.tsx
+++ b/playground/src/Editor/SourceEditor.tsx
@@ -5,19 +5,19 @@
 import Editor, { useMonaco } from "@monaco-editor/react";
 import { MarkerSeverity, MarkerTag } from "monaco-editor";
 import { useCallback, useEffect } from "react";
-import { Check } from "../pkg";
+import { Diagnostic } from "../pkg";
 import { Theme } from "./theme";

 export default function SourceEditor({
  visible,
  source,
  theme,
-  checks,
+  diagnostics,
  onChange,
 }: {
  visible: boolean;
  source: string;
-  checks: Check[];
+  diagnostics: Diagnostic[];
  theme: Theme;
  onChange: (pythonSource: string) => void;
 }) {
@@ -33,15 +33,15 @@ export default function SourceEditor({
    editor.setModelMarkers(
      model,
      "owner",
-      checks.map((check) => ({
-        startLineNumber: check.location.row,
-        startColumn: check.location.column + 1,
-        endLineNumber: check.end_location.row,
-        endColumn: check.end_location.column + 1,
-        message: `${check.code}: ${check.message}`,
+      diagnostics.map((diagnostic) => ({
+        startLineNumber: diagnostic.location.row,
+        startColumn: diagnostic.location.column + 1,
+        endLineNumber: diagnostic.end_location.row,
+        endColumn: diagnostic.end_location.column + 1,
+        message: `${diagnostic.code}: ${diagnostic.message}`,
        severity: MarkerSeverity.Error,
        tags:
-          check.code === "F401" || check.code === "F841"
+          diagnostic.code === "F401" || diagnostic.code === "F841"
            ? [MarkerTag.Unnecessary]
            : [],
      })),
@@ -52,7 +52,7 @@ export default function SourceEditor({
      {
        // @ts-expect-error: The type definition is wrong.
        provideCodeActions: function (model, position) {
-          const actions = checks
+          const actions = diagnostics
            .filter((check) => position.startLineNumber === check.location.row)
            .filter((check) => check.fix)
            .map((check) => ({
@@ -89,7 +89,7 @@ export default function SourceEditor({
    return () => {
      codeActionProvider?.dispose();
    };
-  }, [checks, monaco]);
+  }, [diagnostics, monaco]);

  const handleChange = useCallback(
    (value: string | undefined) => {
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "maturin"

 [project]
 name = "ruff"
-version = "0.0.211"
+version = "0.0.219"
 description = "An extremely fast Python linter, written in Rust."
 authors = [
  { name = "Charlie Marsh", email = "charlie.r.marsh@gmail.com" },
@@ -35,6 +35,7 @@ urls = { repository = "https://github.com/charliermarsh/ruff" }

 [tool.maturin]
 bindings = "bin"
+python-source = "python"
 strip = true

 [tool.setuptools]
--- a/python/ruff/init.py
+++ b/python/ruff/init.py
--- a/python/ruff/main.py
+++ b/python/ruff/main.py
--- a/resources/test/fixtures/flake8_bandit/S113.py
+++ b/resources/test/fixtures/flake8_bandit/S113.py
@@ -0,0 +1,23 @@
+import requests
+
+requests.get('https://gmail.com')
+requests.get('https://gmail.com', timeout=None)
+requests.get('https://gmail.com', timeout=5)
+requests.post('https://gmail.com')
+requests.post('https://gmail.com', timeout=None)
+requests.post('https://gmail.com', timeout=5)
+requests.put('https://gmail.com')
+requests.put('https://gmail.com', timeout=None)
+requests.put('https://gmail.com', timeout=5)
+requests.delete('https://gmail.com')
+requests.delete('https://gmail.com', timeout=None)
+requests.delete('https://gmail.com', timeout=5)
+requests.patch('https://gmail.com')
+requests.patch('https://gmail.com', timeout=None)
+requests.patch('https://gmail.com', timeout=5)
+requests.options('https://gmail.com')
+requests.options('https://gmail.com', timeout=None)
+requests.options('https://gmail.com', timeout=5)
+requests.head('https://gmail.com')
+requests.head('https://gmail.com', timeout=None)
+requests.head('https://gmail.com', timeout=5)
--- a/resources/test/fixtures/flake8_bandit/S324.py
+++ b/resources/test/fixtures/flake8_bandit/S324.py
@@ -0,0 +1,52 @@
+import hashlib
+from hashlib import new as hashlib_new
+from hashlib import sha1 as hashlib_sha1
+
+# Invalid
+
+hashlib.new('md5')
+
+hashlib.new('md4', b'test')
+
+hashlib.new(name='md5', data=b'test')
+
+hashlib.new('MD4', data=b'test')
+
+hashlib.new('sha1')
+
+hashlib.new('sha1', data=b'test')
+
+hashlib.new('sha', data=b'test')
+
+hashlib.new(name='SHA', data=b'test')
+
+hashlib.sha(data=b'test')
+
+hashlib.md5()
+
+hashlib_new('sha1')
+
+hashlib_sha1('sha1')
+
+# usedforsecurity arg only available in Python 3.9+
+hashlib.new('sha1', usedforsecurity=True)
+
+# Valid
+
+hashlib.new('sha256')
+
+hashlib.new('SHA512')
+
+hashlib.sha256(data=b'test')
+
+# usedforsecurity arg only available in Python 3.9+
+hashlib_new(name='sha1', usedforsecurity=False)
+
+# usedforsecurity arg only available in Python 3.9+
+hashlib_sha1(name='sha1', usedforsecurity=False)
+
+# usedforsecurity arg only available in Python 3.9+
+hashlib.md4(usedforsecurity=False)
+
+# usedforsecurity arg only available in Python 3.9+
+hashlib.new(name='sha256', usedforsecurity=False)
--- a/resources/test/fixtures/flake8_bandit/S501.py
+++ b/resources/test/fixtures/flake8_bandit/S501.py
@@ -0,0 +1,40 @@
+import httpx
+import requests
+
+requests.get('https://gmail.com', timeout=30, verify=True)
+requests.get('https://gmail.com', timeout=30, verify=False)
+requests.post('https://gmail.com', timeout=30, verify=True)
+requests.post('https://gmail.com', timeout=30, verify=False)
+requests.put('https://gmail.com', timeout=30, verify=True)
+requests.put('https://gmail.com', timeout=30, verify=False)
+requests.delete('https://gmail.com', timeout=30, verify=True)
+requests.delete('https://gmail.com', timeout=30, verify=False)
+requests.patch('https://gmail.com', timeout=30, verify=True)
+requests.patch('https://gmail.com', timeout=30, verify=False)
+requests.options('https://gmail.com', timeout=30, verify=True)
+requests.options('https://gmail.com', timeout=30, verify=False)
+requests.head('https://gmail.com', timeout=30, verify=True)
+requests.head('https://gmail.com', timeout=30, verify=False)
+
+httpx.request('GET', 'https://gmail.com', verify=True)
+httpx.request('GET', 'https://gmail.com', verify=False)
+httpx.get('https://gmail.com', verify=True)
+httpx.get('https://gmail.com', verify=False)
+httpx.options('https://gmail.com', verify=True)
+httpx.options('https://gmail.com', verify=False)
+httpx.head('https://gmail.com', verify=True)
+httpx.head('https://gmail.com', verify=False)
+httpx.post('https://gmail.com', verify=True)
+httpx.post('https://gmail.com', verify=False)
+httpx.put('https://gmail.com', verify=True)
+httpx.put('https://gmail.com', verify=False)
+httpx.patch('https://gmail.com', verify=True)
+httpx.patch('https://gmail.com', verify=False)
+httpx.delete('https://gmail.com', verify=True)
+httpx.delete('https://gmail.com', verify=False)
+httpx.stream('https://gmail.com', verify=True)
+httpx.stream('https://gmail.com', verify=False)
+httpx.Client()
+httpx.Client(verify=False)
+httpx.AsyncClient()
+httpx.AsyncClient(verify=False)
--- a/resources/test/fixtures/flake8_bandit/S506.py
+++ b/resources/test/fixtures/flake8_bandit/S506.py
@@ -0,0 +1,31 @@
+import json
+import yaml
+from yaml import CSafeLoader
+from yaml import SafeLoader
+from yaml import SafeLoader as NewSafeLoader
+
+
+def test_yaml_load():
+    ystr = yaml.dump({"a": 1, "b": 2, "c": 3})
+    y = yaml.load(ystr)
+    yaml.dump(y)
+    try:
+        y = yaml.load(ystr, Loader=yaml.CSafeLoader)
+    except AttributeError:
+        # CSafeLoader only exists if you build yaml with LibYAML
+        y = yaml.load(ystr, Loader=yaml.SafeLoader)
+
+
+def test_json_load():
+    # no issue should be found
+    j = json.load("{}")
+
+
+yaml.load("{}", Loader=yaml.Loader)
+
+# no issue should be found
+yaml.load("{}", SafeLoader)
+yaml.load("{}", yaml.SafeLoader)
+yaml.load("{}", CSafeLoader)
+yaml.load("{}", yaml.CSafeLoader)
+yaml.load("{}", NewSafeLoader)
--- a/resources/test/fixtures/flake8_bandit/S508.py
+++ b/resources/test/fixtures/flake8_bandit/S508.py
@@ -0,0 +1,6 @@
+from pysnmp.hlapi import CommunityData
+
+CommunityData("public", mpModel=0)  # S508
+CommunityData("public", mpModel=1)  # S508
+
+CommunityData("public", mpModel=2)  # OK
--- a/resources/test/fixtures/flake8_bandit/S509.py
+++ b/resources/test/fixtures/flake8_bandit/S509.py
@@ -0,0 +1,7 @@
+from pysnmp.hlapi import UsmUserData
+
+
+insecure = UsmUserData("securityName")  # S509
+auth_no_priv = UsmUserData("securityName", "authName")  # S509
+
+less_insecure = UsmUserData("securityName", "authName", "privName")  # OK
--- a/resources/test/fixtures/flake8_bugbear/B023.py
+++ b/resources/test/fixtures/flake8_bugbear/B023.py
@@ -25,10 +25,10 @@ for x in range(3):


 def check_inside_functions_too():
-    ls = [lambda: x for x in range(2)]
-    st = {lambda: x for x in range(2)}
-    gn = (lambda: x for x in range(2))
-    dt = {x: lambda: x for x in range(2)}
+    ls = [lambda: x for x in range(2)]  # error
+    st = {lambda: x for x in range(2)}  # error
+    gn = (lambda: x for x in range(2))  # error
+    dt = {x: lambda: x for x in range(2)}  # error


 async def pointless_async_iterable():
@@ -37,9 +37,9 @@ async def pointless_async_iterable():

 async def container_for_problems():
    async for x in pointless_async_iterable():
-        functions.append(lambda: x)
+        functions.append(lambda: x)  # error

-    [lambda: x async for x in pointless_async_iterable()]
+    [lambda: x async for x in pointless_async_iterable()]  # error


 a = 10
@@ -47,10 +47,10 @@ b = 0
 while True:
    a = a_ = a - 1
    b += 1
-    functions.append(lambda: a)
-    functions.append(lambda: a_)
-    functions.append(lambda: b)
-    functions.append(lambda: c)  # not a name error because of late binding!
+    functions.append(lambda: a)  # error
+    functions.append(lambda: a_)  # error
+    functions.append(lambda: b)  # error
+    functions.append(lambda: c)  # error, but not a name error due to late binding
    c: bool = a > 3
    if not c:
        break
@@ -58,7 +58,7 @@ while True:
 # Nested loops should not duplicate reports
 for j in range(2):
    for k in range(3):
-        lambda: j * k
+        lambda: j * k  # error


 for j, k, l in [(1, 2, 3)]:
@@ -80,3 +80,95 @@ for var in range(2):

 for i in range(3):
    lambda: f"{i}"
+
+
+# `query` is defined in the function, so also defining it in the loop should be OK.
+for name in ["a", "b"]:
+    query = name
+
+    def myfunc(x):
+        query = x
+        query_post = x
+        _ = query
+        _ = query_post
+
+    query_post = name  # in case iteration order matters
+
+
+# Bug here because two dict comprehensions reference `name`, one of which is inside
+# the lambda.  This should be totally fine, of course.
+_ = {
+    k: v
+    for k, v in reduce(
+        lambda data, event: merge_mappings(
+            [data, {name: f(caches, data, event) for name, f in xx}]
+        ),
+        events,
+        {name: getattr(group, name) for name in yy},
+    ).items()
+    if k in backfill_fields
+}
+
+
+# OK to define lambdas if they're immediately consumed, typically as the `key=`
+# argument or in a consumed `filter()` (even if a comprehension is better style)
+for x in range(2):
+    # It's not a complete get-out-of-linting-free construct - these should fail:
+    min([None, lambda: x], key=repr)
+    sorted([None, lambda: x], key=repr)
+    any(filter(bool, [None, lambda: x]))
+    list(filter(bool, [None, lambda: x]))
+    all(reduce(bool, [None, lambda: x]))
+
+    # But all these should be OK:
+    min(range(3), key=lambda y: x * y)
+    max(range(3), key=lambda y: x * y)
+    sorted(range(3), key=lambda y: x * y)
+
+    any(map(lambda y: x < y, range(3)))
+    all(map(lambda y: x < y, range(3)))
+    set(map(lambda y: x < y, range(3)))
+    list(map(lambda y: x < y, range(3)))
+    tuple(map(lambda y: x < y, range(3)))
+    sorted(map(lambda y: x < y, range(3)))
+    frozenset(map(lambda y: x < y, range(3)))
+
+    any(filter(lambda y: x < y, range(3)))
+    all(filter(lambda y: x < y, range(3)))
+    set(filter(lambda y: x < y, range(3)))
+    list(filter(lambda y: x < y, range(3)))
+    tuple(filter(lambda y: x < y, range(3)))
+    sorted(filter(lambda y: x < y, range(3)))
+    frozenset(filter(lambda y: x < y, range(3)))
+
+    any(reduce(lambda y: x | y, range(3)))
+    all(reduce(lambda y: x | y, range(3)))
+    set(reduce(lambda y: x | y, range(3)))
+    list(reduce(lambda y: x | y, range(3)))
+    tuple(reduce(lambda y: x | y, range(3)))
+    sorted(reduce(lambda y: x | y, range(3)))
+    frozenset(reduce(lambda y: x | y, range(3)))
+
+    import functools
+
+    any(functools.reduce(lambda y: x | y, range(3)))
+    all(functools.reduce(lambda y: x | y, range(3)))
+    set(functools.reduce(lambda y: x | y, range(3)))
+    list(functools.reduce(lambda y: x | y, range(3)))
+    tuple(functools.reduce(lambda y: x | y, range(3)))
+    sorted(functools.reduce(lambda y: x | y, range(3)))
+    frozenset(functools.reduce(lambda y: x | y, range(3)))
+
+# OK because the lambda which references a loop variable is defined in a `return`
+# statement, and after we return the loop variable can't be redefined.
+# In principle we could do something fancy with `break`, but it's not worth it.
+def iter_f(names):
+    for name in names:
+        if exists(name):
+            return lambda: name if exists(name) else None
+
+        if foo(name):
+            return [lambda: name]  # known false alarm
+
+        if False:
+            return [lambda: i for i in range(3)]  # error
--- a/resources/test/fixtures/flake8_comprehensions/C400.py
+++ b/resources/test/fixtures/flake8_comprehensions/C400.py
@@ -2,3 +2,10 @@ x = list(x for x in range(3))
 x = list(
    x for x in range(3)
 )
+
+
+def list(*args, **kwargs):
+    return None
+
+
+list(x for x in range(3))
--- a/resources/test/fixtures/flake8_comprehensions/C401.py
+++ b/resources/test/fixtures/flake8_comprehensions/C401.py
@@ -2,3 +2,10 @@ x = set(x for x in range(3))
 x = set(
    x for x in range(3)
 )
+
+
+def set(*args, **kwargs):
+    return None
+
+
+set(x for x in range(3))
--- a/resources/test/fixtures/flake8_comprehensions/C408.py
+++ b/resources/test/fixtures/flake8_comprehensions/C408.py
@@ -3,3 +3,10 @@ l = list()
 d1 = dict()
 d2 = dict(a=1)
 d3 = dict(**d2)
+
+
+def list():
+    return [1, 2, 3]
+
+
+a = list()
--- a/resources/test/fixtures/flake8_comprehensions/C413.py
+++ b/resources/test/fixtures/flake8_comprehensions/C413.py
@@ -4,3 +4,10 @@ list(sorted(x))
 reversed(sorted(x))
 reversed(sorted(x, key=lambda e: e))
 reversed(sorted(x, reverse=True))
+
+
+def reversed(*args, **kwargs):
+    return None
+
+
+reversed(sorted(x, reverse=True))
--- a/resources/test/fixtures/flake8_pie/PIE794.py
+++ b/resources/test/fixtures/flake8_pie/PIE794.py
@@ -31,3 +31,10 @@ class User(BaseModel):
    @buzz.setter
    def buzz(self, value: str | int) -> None:
        ...
+
+
+class User:
+    bar: str = StringField()
+    foo: bool = BooleanField()
+    # ...
+    bar = StringField()  # PIE794
--- a/resources/test/fixtures/flake8_pytest_style/PT009.py
+++ b/resources/test/fixtures/flake8_pytest_style/PT009.py
@@ -1,9 +1,76 @@
-import pytest
+import unittest


-def test_xxx():
-    assert 1 == 1  # OK no parameters
+class Test(unittest.TestCase):
+    def test_xxx(self):
+        assert 1 == 1  # OK no parameters

+    def test_assert_true(self):
+        expr = 1
+        msg = "Must be True"
+        self.assertTrue(expr)  # Error
+        self.assertTrue(expr=expr)  # Error
+        self.assertTrue(expr, msg)  # Error
+        self.assertTrue(expr=expr, msg=msg)  # Error
+        self.assertTrue(msg=msg, expr=expr)  # Error
+        self.assertTrue(*(expr, msg))  # Error, unfixable
+        self.assertTrue(**{"expr": expr, "msg": msg})  # Error, unfixable
+        self.assertTrue(msg=msg, expr=expr, unexpected_arg=False)  # Error, unfixable
+        self.assertTrue(msg=msg)  # Error, unfixable

-def test_xxx():
-    self.assertEqual(1, 1)  # Error
+    def test_assert_false(self):
+        self.assertFalse(True)  # Error
+
+    def test_assert_equal(self):
+        self.assertEqual(1, 2)  # Error
+
+    def test_assert_not_equal(self):
+        self.assertNotEqual(1, 1)  # Error
+
+    def test_assert_greater(self):
+        self.assertGreater(1, 2)  # Error
+
+    def test_assert_greater_equal(self):
+        self.assertGreaterEqual(1, 2)  # Error
+
+    def test_assert_less(self):
+        self.assertLess(2, 1)  # Error
+
+    def test_assert_less_equal(self):
+        self.assertLessEqual(1, 2)  # Error
+
+    def test_assert_in(self):
+        self.assertIn(1, [2, 3])  # Error
+
+    def test_assert_not_in(self):
+        self.assertNotIn(2, [2, 3])  # Error
+
+    def test_assert_is_none(self):
+        self.assertIsNone(0)  # Error
+
+    def test_assert_is_not_none(self):
+        self.assertIsNotNone(0)  # Error
+
+    def test_assert_is(self):
+        self.assertIs([], [])  # Error
+
+    def test_assert_is_not(self):
+        self.assertIsNot(1, 1)  # Error
+
+    def test_assert_is_instance(self):
+        self.assertIsInstance(1, str)  # Error
+
+    def test_assert_is_not_instance(self):
+        self.assertNotIsInstance(1, int)  # Error
+
+    def test_assert_regex(self):
+        self.assertRegex("abc", r"def")  # Error
+
+    def test_assert_not_regex(self):
+        self.assertNotRegex("abc", r"abc")  # Error
+
+    def test_assert_regexp_matches(self):
+        self.assertRegexpMatches("abc", r"def")  # Error
+
+    def test_assert_not_regexp_matches(self):
+        self.assertNotRegex("abc", r"abc")  # Error
--- a/resources/test/fixtures/flake8_quotes/docstring_doubles_function.py
+++ b/resources/test/fixtures/flake8_quotes/docstring_doubles_function.py
@@ -17,6 +17,15 @@ def fun_with_params_no_docstring(a, b="""
 """ """docstring"""):
    pass

+
 def fun_with_params_no_docstring2(a, b=c[foo():], c=\
    """ not a docstring """):
    pass
+
+
+def function_with_single_docstring(a):
+    "Single line docstring"
+
+
+def double_inside_single(a):
+    'Double inside "single "'
--- a/resources/test/fixtures/flake8_quotes/docstring_singles_function.py
+++ b/resources/test/fixtures/flake8_quotes/docstring_singles_function.py
@@ -13,11 +13,19 @@ def foo2():


 def fun_with_params_no_docstring(a, b='''
-    not a 
+    not a
 ''' '''docstring'''):
    pass

+
 def fun_with_params_no_docstring2(a, b=c[foo():], c=\
    ''' not a docstring '''):
    pass

+
+def function_with_single_docstring(a):
+    'Single line docstring'
+
+
+def double_inside_single(a):
+    "Double inside 'single '"
--- a/resources/test/fixtures/flake8_simplify/SIM101.py
+++ b/resources/test/fixtures/flake8_simplify/SIM101.py
@@ -0,0 +1,23 @@
+if isinstance(a, int) or isinstance(a, float):  # SIM101
+    pass
+
+if isinstance(a, (int, float)) or isinstance(a, bool):  # SIM101
+    pass
+
+if isinstance(a, int) or isinstance(a, float) or isinstance(b, bool):  # SIM101
+    pass
+
+if isinstance(b, bool) or isinstance(a, int) or isinstance(a, float):  # SIM101
+    pass
+
+if isinstance(a, int) or isinstance(b, bool) or isinstance(a, float):  # SIM101
+    pass
+
+if (isinstance(a, int) or isinstance(a, float)) and isinstance(b, bool):  # SIM101
+    pass
+
+if isinstance(a, int) and isinstance(b, bool) or isinstance(a, float):
+    pass
+
+if isinstance(a, bool) or isinstance(b, str):
+    pass
--- a/resources/test/fixtures/flake8_simplify/SIM103.py
+++ b/resources/test/fixtures/flake8_simplify/SIM103.py
@@ -0,0 +1,20 @@
+def f():
+    if a:  # SIM103
+        return True
+    else:
+        return False
+
+
+def f():
+    if a:  # OK
+        foo()
+        return True
+    else:
+        return False
+
+
+def f():
+    if a:  # OK
+        return "foo"
+    else:
+        return False
--- a/resources/test/fixtures/flake8_simplify/SIM108.py
+++ b/resources/test/fixtures/flake8_simplify/SIM108.py
@@ -0,0 +1,93 @@
+# SIM108
+if a:
+    b = c
+else:
+    b = d
+
+# OK
+b = c if a else d
+
+# OK
+if a:
+    b = c
+elif c:
+    b = a
+else:
+    b = d
+
+# OK
+if True:
+    pass
+elif a:
+    b = 1
+else:
+    b = 2
+
+# OK (false negative)
+if True:
+    pass
+else:
+    if a:
+        b = 1
+    else:
+        b = 2
+
+
+import sys
+
+# OK
+if sys.version_info >= (3, 9):
+    randbytes = random.randbytes
+else:
+    randbytes = _get_random_bytes
+
+# OK
+if sys.platform == "darwin":
+    randbytes = random.randbytes
+else:
+    randbytes = _get_random_bytes
+
+# OK
+if sys.platform.startswith("linux"):
+    randbytes = random.randbytes
+else:
+    randbytes = _get_random_bytes
+
+
+# OK (includes comments)
+if x > 0:
+    # test test
+    abc = x
+else:
+    # test test test
+    abc = -x
+
+
+# OK (too long)
+if parser.errno == BAD_FIRST_LINE:
+    req = wrappers.Request(sock, server=self._server)
+else:
+    req = wrappers.Request(
+        sock,
+        parser.get_method(),
+        parser.get_scheme() or _scheme,
+        parser.get_path(),
+        parser.get_version(),
+        parser.get_query_string(),
+        server=self._server,
+    )
+
+
+# SIM108
+if a:
+    b = cccccccccccccccccccccccccccccccccccc
+else:
+    b = ddddddddddddddddddddddddddddddddddddd
+
+
+# OK (too long)
+if True:
+    if a:
+        b = cccccccccccccccccccccccccccccccccccc
+    else:
+        b = ddddddddddddddddddddddddddddddddddddd
--- a/resources/test/fixtures/flake8_simplify/SIM109.py
+++ b/resources/test/fixtures/flake8_simplify/SIM109.py
@@ -0,0 +1,7 @@
+# Bad
+if a == b or a == c:
+    d
+
+# Good
+if a in (b, c):
+    d
--- a/resources/test/fixtures/flake8_simplify/SIM112.py
+++ b/resources/test/fixtures/flake8_simplify/SIM112.py
@@ -0,0 +1,19 @@
+import os
+
+# Bad
+os.environ['foo']
+
+os.environ.get('foo')
+
+os.environ.get('foo', 'bar')
+
+os.getenv('foo')
+
+# Good
+os.environ['FOO']
+
+os.environ.get('FOO')
+
+os.environ.get('FOO', 'bar')
+
+os.getenv('FOO')
--- a/resources/test/fixtures/flake8_simplify/SIM115.py
+++ b/resources/test/fixtures/flake8_simplify/SIM115.py
@@ -0,0 +1,6 @@
+f = open('foo.txt')  # SIM115
+data = f.read()
+f.close()
+
+with open('foo.txt') as f:  # OK
+    data = f.read()
--- a/resources/test/fixtures/flake8_simplify/SIM201.py
+++ b/resources/test/fixtures/flake8_simplify/SIM201.py
@@ -0,0 +1,17 @@
+if not a == b:  # SIM201
+    pass
+
+if not a == (b + c):  # SIM201
+    pass
+
+if not (a + b) == c:  # SIM201
+    pass
+
+if not a != b:  # OK
+    pass
+
+if a == b:  # OK
+    pass
+
+if not a == b:  # OK
+    raise ValueError()
--- a/resources/test/fixtures/flake8_simplify/SIM202.py
+++ b/resources/test/fixtures/flake8_simplify/SIM202.py
@@ -0,0 +1,14 @@
+if not a != b:  # SIM202
+    pass
+
+if not a != (b + c):  # SIM202
+    pass
+
+if not (a + b) != c:  # SIM202
+    pass
+
+if not a == b:  # OK
+    pass
+
+if a != b:  # OK
+    pass
--- a/resources/test/fixtures/flake8_simplify/SIM208.py
+++ b/resources/test/fixtures/flake8_simplify/SIM208.py
@@ -0,0 +1,14 @@
+if not (not a):  # SIM208
+    pass
+
+if not (not (a == b)):  # SIM208
+    pass
+
+if not a:  # OK
+    pass
+
+if not a == b:  # OK
+    pass
+
+if not a != b:  # OK
+    pass
--- a/resources/test/fixtures/flake8_simplify/SIM210.py
+++ b/resources/test/fixtures/flake8_simplify/SIM210.py
@@ -0,0 +1,7 @@
+a = True if b else False  # SIM210
+
+a = True if b != c else False  # SIM210
+
+a = True if b + c else False  # SIM210
+
+a = False if b else True  # OK
--- a/resources/test/fixtures/flake8_simplify/SIM211.py
+++ b/resources/test/fixtures/flake8_simplify/SIM211.py
@@ -0,0 +1,7 @@
+a = False if b else True  # SIM211
+
+a = False if b != c else True  # SIM211
+
+a = False if b + c else True  # SIM211
+
+a = True if b else False  # OK
--- a/resources/test/fixtures/flake8_simplify/SIM212.py
+++ b/resources/test/fixtures/flake8_simplify/SIM212.py
@@ -0,0 +1,7 @@
+c = b if not a else a  # SIM212
+
+c = b + c if not a else a  # SIM212
+
+c = b if not x else a  # OK
+
+c = a if a else b  # OK
--- a/resources/test/fixtures/flake8_simplify/SIM401.py
+++ b/resources/test/fixtures/flake8_simplify/SIM401.py
@@ -0,0 +1,81 @@
+###
+# Positive cases
+###
+
+# SIM401 (pattern-1)
+if key in a_dict:
+    var = a_dict[key]
+else:
+    var = "default1"
+
+# SIM401 (pattern-2)
+if key not in a_dict:
+    var = "default2"
+else:
+    var = a_dict[key]
+
+# SIM401 (default with a complex expression)
+if key in a_dict:
+    var = a_dict[key]
+else:
+    var = val1 + val2
+
+# SIM401 (complex expression in key)
+if keys[idx] in a_dict:
+    var = a_dict[keys[idx]]
+else:
+    var = "default"
+
+# SIM401 (complex expression in dict)
+if key in dicts[idx]:
+    var = dicts[idx][key]
+else:
+    var = "default"
+
+# SIM401 (complex expression in var)
+if key in a_dict:
+    vars[idx] = a_dict[key]
+else:
+    vars[idx] = "default"
+
+###
+# Negative cases
+###
+
+# OK (false negative)
+if not key in a_dict:
+    var = "default"
+else:
+    var = a_dict[key]
+
+# OK (different dict)
+if key in a_dict:
+    var = other_dict[key]
+else:
+    var = "default"
+
+# OK (different key)
+if key in a_dict:
+    var = a_dict[other_key]
+else:
+    var = "default"
+
+# OK (different var)
+if key in a_dict:
+    var = a_dict[key]
+else:
+    other_var = "default"
+
+# OK (extra vars in body)
+if key in a_dict:
+    var = a_dict[key]
+    var2 = value2
+else:
+    var = "default"
+
+# OK (extra vars in orelse)
+if key in a_dict:
+    var = a_dict[key]
+else:
+    var2 = value2
+    var = "default"
--- a/resources/test/fixtures/flake8_unused_arguments/ARG.py
+++ b/resources/test/fixtures/flake8_unused_arguments/ARG.py
@@ -77,6 +77,34 @@ class C:
    def f(x):
        ...

+    def f(self, x):
+        """Docstring."""
+
+    def f(self, x):
+        """Docstring."""
+        ...
+
+    def f(self, x):
+        pass
+
+    def f(self, x):
+        raise NotImplementedError
+
+    def f(self, x):
+        raise NotImplementedError()
+
+    def f(self, x):
+        raise NotImplementedError("...")
+
+    def f(self, x):
+        raise NotImplemented
+
+    def f(self, x):
+        raise NotImplemented()
+
+    def f(self, x):
+        raise NotImplemented("...")
+
    ###
    # Unused functions attached to abstract methods (OK).
    ###
@@ -153,3 +181,17 @@ def f(a: int, b: int) -> str:

 def f(a, b):
    return f"{a}{b}"
+
+
+###
+# Unused arguments on magic methods.
+###
+class C:
+    def __init__(self, x) -> None:
+        print("Hello, world!")
+
+    def __str__(self) -> str:
+        return "Hello, world!"
+
+    def __exit__(self, exc_type, exc_value, traceback) -> None:
+        print("Hello, world!")
--- a/resources/test/fixtures/isort/force_sort_within_sections.py
+++ b/resources/test/fixtures/isort/force_sort_within_sections.py
@@ -0,0 +1,11 @@
+from a import a1  # import_from
+from c import * # import_from_star
+import a  # import
+import c.d
+import b as b1  # import_as
+
+from ..parent import *
+from .my import fn
+from . import my
+from .my.nested import fn2
+from ...grandparent import fn3
--- a/resources/test/fixtures/isort/required_imports/comment.py
+++ b/resources/test/fixtures/isort/required_imports/comment.py
@@ -0,0 +1,3 @@
+#!/usr/bin/env python3
+
+x = 1
--- a/resources/test/fixtures/isort/required_imports/docstring.py
+++ b/resources/test/fixtures/isort/required_imports/docstring.py
@@ -0,0 +1,3 @@
+"""Hello, world!"""
+
+x = 1
--- a/resources/test/fixtures/isort/required_imports/docstring_only.py
+++ b/resources/test/fixtures/isort/required_imports/docstring_only.py
@@ -0,0 +1 @@
+"""Hello, world!"""
--- a/resources/test/fixtures/isort/required_imports/docstring_with_continuation.py
+++ b/resources/test/fixtures/isort/required_imports/docstring_with_continuation.py
@@ -0,0 +1,2 @@
+"""Hello, world!"""; x = \
+    1; y = 2
--- a/resources/test/fixtures/isort/required_imports/docstring_with_semicolon.py
+++ b/resources/test/fixtures/isort/required_imports/docstring_with_semicolon.py
@@ -0,0 +1 @@
+"""Hello, world!"""; x = 1
--- a/resources/test/fixtures/isort/required_imports/empty.py
+++ b/resources/test/fixtures/isort/required_imports/empty.py
--- a/resources/test/fixtures/isort/required_imports/existing_import.py
+++ b/resources/test/fixtures/isort/required_imports/existing_import.py
@@ -0,0 +1,2 @@
+from __future__ import generator_stop
+import os
--- a/resources/test/fixtures/isort/skip.py
+++ b/resources/test/fixtures/isort/skip.py
@@ -1,10 +1,20 @@
-# isort: off
-import sys
-import os
-import collections
-# isort: on
+def f():
+    # isort: off
+    import sys
+    import os
+    import collections
+    # isort: on

-import sys
-import os  # isort: skip
-import collections
-import abc
+
+def f():
+    import sys
+    import os  # isort: skip
+    import collections
+    import abc
+
+
+def f():
+    import sys
+    import os  # isort:skip
+    import collections
+    import abc
--- a/resources/test/fixtures/isort/split.py
+++ b/resources/test/fixtures/isort/split.py
@@ -3,7 +3,10 @@ import f

 # isort: split

-import a
-import b
 import c
 import d
+
+# isort: split  
+
+import a
+import b
--- a/resources/test/fixtures/pycodestyle/E999.py
+++ b/resources/test/fixtures/pycodestyle/E999.py
@@ -1,2 +1,4 @@
+
 def x():

+
--- a/resources/test/fixtures/pycodestyle/W505.py
+++ b/resources/test/fixtures/pycodestyle/W505.py
@@ -0,0 +1,15 @@
+#!/usr/bin/env python3
+"""Here's a top-level docstring that's over the limit."""
+
+
+def f():
+    """Here's a docstring that's also over the limit."""
+
+    x = 1  # Here's a comment that's over the limit, but it's not standalone.
+
+    # Here's a standalone comment that's over the limit.
+
+    print("Here's a string that's over the limit, but it's not a docstring.")
+
+
+"This is also considered a docstring, and is over the limit."
--- a/resources/test/fixtures/pyflakes/F601.py
+++ b/resources/test/fixtures/pyflakes/F601.py
@@ -10,3 +10,41 @@ x = {
    b"123": 1,
    b"123": 4,
 }
+
+x = {
+    "a": 1,
+    "a": 2,
+    "a": 3,
+    "a": 3,
+}
+
+x = {
+    "a": 1,
+    "a": 2,
+    "a": 3,
+    "a": 3,
+    "a": 4,
+}
+
+x = {
+    "a": 1,
+    "a": 1,
+    "a": 2,
+    "a": 3,
+    "a": 4,
+}
+
+x = {
+    a: 1,
+    "a": 1,
+    a: 1,
+    "a": 2,
+    a: 2,
+    "a": 3,
+    a: 3,
+    "a": 3,
+    a: 4,
+}
+
+x = {"a": 1, "a": 1}
+x = {"a": 1, "b": 2, "a": 1}
--- a/resources/test/fixtures/pyflakes/F602.py
+++ b/resources/test/fixtures/pyflakes/F602.py
@@ -5,3 +5,41 @@ x = {
    a: 2,
    b: 3,
 }
+
+x = {
+    a: 1,
+    a: 2,
+    a: 3,
+    a: 3,
+}
+
+x = {
+    a: 1,
+    a: 2,
+    a: 3,
+    a: 3,
+    a: 4,
+}
+
+x = {
+    a: 1,
+    a: 1,
+    a: 2,
+    a: 3,
+    a: 4,
+}
+
+x = {
+    a: 1,
+    "a": 1,
+    a: 1,
+    "a": 2,
+    a: 2,
+    "a": 3,
+    a: 3,
+    "a": 3,
+    a: 4,
+}
+
+x = {a: 1, a: 1}
+x = {a: 1, b: 2, a: 1}
--- a/resources/test/fixtures/pyflakes/F841_3.py
+++ b/resources/test/fixtures/pyflakes/F841_3.py
@@ -0,0 +1,46 @@
+"""Test case for autofixing F841 violations."""
+
+
+def f():
+    x = 1
+    y = 2
+
+    z = 3
+    print(z)
+
+
+def f():
+    x: int = 1
+    y: int = 2
+
+    z: int = 3
+    print(z)
+
+
+def f():
+    with foo() as x1:
+        pass
+
+    with foo() as (x2, y2):
+        pass
+
+    with (foo() as x3, foo() as y3, foo() as z3):
+        pass
+
+
+def f():
+    (x1, y1) = (1, 2)
+    (x2, y2) = coords2 = (1, 2)
+    coords3 = (x3, y3) = (1, 2)
+
+
+def f():
+    try:
+        1 / 0
+    except ValueError as x1:
+        pass
+
+    try:
+        1 / 0
+    except (ValueError, ZeroDivisionError) as x2:
+        pass
--- a/resources/test/fixtures/pyflakes/builtins.py
+++ b/resources/test/fixtures/pyflakes/builtins.py
@@ -0,0 +1 @@
+_("Translations")
--- a/resources/test/fixtures/pyflakes/typing_modules.py
+++ b/resources/test/fixtures/pyflakes/typing_modules.py
@@ -0,0 +1,7 @@
+from typing import Union
+
+from airflow.typing_compat import Literal, Optional
+
+
+X = Union[Literal[False], Literal["db"]]
+y = Optional["Class"]
--- a/resources/test/fixtures/pyupgrade/UP024_3.py
+++ b/resources/test/fixtures/pyupgrade/UP024_3.py
@@ -0,0 +1,8 @@
+class SocketError(Exception):
+    pass
+
+
+try:
+    raise SocketError()
+except SocketError:
+    pass
--- a/resources/test/fixtures/pyupgrade/UP028_1.py
+++ b/resources/test/fixtures/pyupgrade/UP028_1.py
@@ -111,3 +111,13 @@ def f():
    class C:
        def __init__(self):
            print(x)
+
+
+def f():
+    for x in y:
+        yield x, x + 1
+
+
+def f():
+    for x, y in z:
+        yield x, y, x + y
--- a/resources/test/fixtures/pyupgrade/UP030_0.py
+++ b/resources/test/fixtures/pyupgrade/UP030_0.py
@@ -0,0 +1,36 @@
+# Invalid calls; errors expected.
+
+"{0}" "{1}" "{2}".format(1, 2, 3)
+
+"a {3} complicated {1} string with {0} {2}".format(
+    "first", "second", "third", "fourth"
+)
+
+'{0}'.format(1)
+
+'{0:x}'.format(30)
+
+x = '{0}'.format(1)
+
+'''{0}\n{1}\n'''.format(1, 2)
+
+x = "foo {0}" \
+    "bar {1}".format(1, 2)
+
+("{0}").format(1)
+
+"\N{snowman} {0}".format(1)
+
+'{' '0}'.format(1)
+
+# These will not change because we are waiting for libcst to fix this issue:
+# https://github.com/Instagram/LibCST/issues/846
+print(
+    'foo{0}'
+    'bar{1}'.format(1, 2)
+)
+
+print(
+    'foo{0}'  # ohai\n"
+    'bar{1}'.format(1, 2)
+)
--- a/resources/test/fixtures/pyupgrade/UP030_1.py
+++ b/resources/test/fixtures/pyupgrade/UP030_1.py
@@ -0,0 +1,23 @@
+# Valid calls; no errors expected.
+
+'{}'.format(1)
+
+
+x = ('{0} {1}',)
+
+'{0} {0}'.format(1)
+
+'{0:<{1}}'.format(1, 4)
+
+f"{0}".format(a)
+
+f"{0}".format(1)
+
+print(f"{0}".format(1))
+
+# I did not include the following tests because ruff does not seem to work with
+# invalid python syntax (which is a good thing)
+
+# "{0}"format(1)
+# '{'.format(1)", "'}'.format(1)
+# ("{0}" # {1}\n"{2}").format(1, 2, 3)
--- a/ruff.schema.json
+++ b/ruff.schema.json
--- a/ruff_dev/Cargo.toml
+++ b/ruff_dev/Cargo.toml
@@ -1,19 +1,22 @@
 [package]
 name = "ruff_dev"
-version = "0.0.211"
+version = "0.0.219"
 edition = "2021"

+[lib]
+name = "ruff_dev"
+doctest = false
+
 [dependencies]
 anyhow = { version = "1.0.66" }
 clap = { version = "4.0.1", features = ["derive"] }
-codegen = { version = "0.2.0" }
 itertools = { version = "0.10.5" }
 libcst = { git = "https://github.com/charliermarsh/LibCST", rev = "f2f0b7a487a8725d161fe8b3ed73a6758b21e177" }
 once_cell = { version = "1.16.0" }
 ruff = { path = ".." }
-rustpython-ast = { features = ["unparse"], git = "https://github.com/RustPython/RustPython.git", rev = "4d53c7cb27c0379adf8b51c4d3d0d2174f41d590" }
-rustpython-common = { git = "https://github.com/RustPython/RustPython.git", rev = "4d53c7cb27c0379adf8b51c4d3d0d2174f41d590" }
-rustpython-parser = { features = ["lalrpop"], git = "https://github.com/RustPython/RustPython.git", rev = "4d53c7cb27c0379adf8b51c4d3d0d2174f41d590" }
+rustpython-ast = { features = ["unparse"], git = "https://github.com/RustPython/RustPython.git", rev = "d532160333ffeb6dbeca2c2728c2391cd1e53b7f" }
+rustpython-common = { git = "https://github.com/RustPython/RustPython.git", rev = "d532160333ffeb6dbeca2c2728c2391cd1e53b7f" }
+rustpython-parser = { features = ["lalrpop"], git = "https://github.com/RustPython/RustPython.git", rev = "d532160333ffeb6dbeca2c2728c2391cd1e53b7f" }
 schemars = { version = "0.8.11" }
 serde_json = {version="1.0.91"}
 strum = { version = "0.24.1", features = ["strum_macros"] }
--- a/ruff_dev/src/generate_all.rs
+++ b/ruff_dev/src/generate_all.rs
@@ -3,10 +3,7 @@
 use anyhow::Result;
 use clap::Args;

-use crate::{
-    generate_check_code_prefix, generate_cli_help, generate_json_schema, generate_options,
-    generate_rules_table,
-};
+use crate::{generate_cli_help, generate_json_schema, generate_options, generate_rules_table};

 #[derive(Args)]
 pub struct Cli {
@@ -16,9 +13,6 @@ pub struct Cli {
 }

 pub fn main(cli: &Cli) -> Result<()> {
-    generate_check_code_prefix::main(&generate_check_code_prefix::Cli {
-        dry_run: cli.dry_run,
-    })?;
    generate_json_schema::main(&generate_json_schema::Cli {
        dry_run: cli.dry_run,
    })?;
--- a/ruff_dev/src/generate_check_code_prefix.rs
+++ b/ruff_dev/src/generate_check_code_prefix.rs
@@ -1,221 +0,0 @@
-//! Generate the `CheckCodePrefix` enum.
-
-use std::collections::{BTreeMap, BTreeSet};
-use std::fs;
-use std::io::Write;
-use std::path::PathBuf;
-use std::process::{Command, Output, Stdio};
-
-use anyhow::{ensure, Result};
-use clap::Parser;
-use codegen::{Scope, Type, Variant};
-use itertools::Itertools;
-use ruff::registry::{CheckCode, PREFIX_REDIRECTS};
-use strum::IntoEnumIterator;
-
-const ALL: &str = "ALL";
-
-#[derive(Parser)]
-#[command(author, version, about, long_about = None)]
-pub struct Cli {
-    /// Write the generated source code to stdout (rather than to
-    /// `src/registry_gen.rs`).
-    #[arg(long)]
-    pub(crate) dry_run: bool,
-}
-
-pub fn main(cli: &Cli) -> Result<()> {
-    // Build up a map from prefix to matching CheckCodes.
-    let mut prefix_to_codes: BTreeMap<String, BTreeSet<CheckCode>> = BTreeMap::default();
-    for check_code in CheckCode::iter() {
-        let code_str: String = check_code.as_ref().to_string();
-        let code_prefix_len = code_str
-            .chars()
-            .take_while(|char| char.is_alphabetic())
-            .count();
-        let code_suffix_len = code_str.len() - code_prefix_len;
-        for i in 0..=code_suffix_len {
-            let prefix = code_str[..code_prefix_len + i].to_string();
-            prefix_to_codes
-                .entry(prefix)
-                .or_default()
-                .insert(check_code.clone());
-        }
-        prefix_to_codes
-            .entry(ALL.to_string())
-            .or_default()
-            .insert(check_code.clone());
-    }
-
-    // Add any prefix aliases (e.g., "U" to "UP").
-    for (alias, check_code) in PREFIX_REDIRECTS.iter() {
-        prefix_to_codes.insert(
-            (*alias).to_string(),
-            prefix_to_codes
-                .get(&check_code.as_ref().to_string())
-                .unwrap_or_else(|| panic!("Unknown CheckCode: {alias:?}"))
-                .clone(),
-        );
-    }
-
-    let mut scope = Scope::new();
-
-    // Create the `CheckCodePrefix` definition.
-    let mut gen = scope
-        .new_enum("CheckCodePrefix")
-        .vis("pub")
-        .derive("EnumString")
-        .derive("AsRefStr")
-        .derive("Debug")
-        .derive("PartialEq")
-        .derive("Eq")
-        .derive("PartialOrd")
-        .derive("Ord")
-        .derive("Clone")
-        .derive("Serialize")
-        .derive("Deserialize")
-        .derive("JsonSchema");
-    for prefix in prefix_to_codes.keys() {
-        gen = gen.push_variant(Variant::new(prefix.to_string()));
-    }
-
-    // Create the `SuffixLength` definition.
-    scope
-        .new_enum("SuffixLength")
-        .vis("pub")
-        .derive("PartialEq")
-        .derive("Eq")
-        .derive("PartialOrd")
-        .derive("Ord")
-        .push_variant(Variant::new("None"))
-        .push_variant(Variant::new("Zero"))
-        .push_variant(Variant::new("One"))
-        .push_variant(Variant::new("Two"))
-        .push_variant(Variant::new("Three"))
-        .push_variant(Variant::new("Four"));
-
-    // Create the `match` statement, to map from definition to relevant codes.
-    let mut gen = scope
-        .new_impl("CheckCodePrefix")
-        .new_fn("codes")
-        .arg_ref_self()
-        .ret(Type::new("Vec<CheckCode>"))
-        .vis("pub")
-        .line("#[allow(clippy::match_same_arms)]")
-        .line("match self {");
-    for (prefix, codes) in &prefix_to_codes {
-        if let Some(target) = PREFIX_REDIRECTS.get(&prefix.as_str()) {
-            gen = gen.line(format!(
-                "CheckCodePrefix::{prefix} => {{ one_time_warning!(\"{{}}{{}} {{}}\", \
-                 \"warning\".yellow().bold(), \":\".bold(), \"`{}` has been remapped to \
-                 `{}`\".bold()); \n vec![{}] }}",
-                prefix,
-                target.as_ref(),
-                codes
-                    .iter()
-                    .map(|code| format!("CheckCode::{}", code.as_ref()))
-                    .join(", ")
-            ));
-        } else {
-            gen = gen.line(format!(
-                "CheckCodePrefix::{prefix} => vec![{}],",
-                codes
-                    .iter()
-                    .map(|code| format!("CheckCode::{}", code.as_ref()))
-                    .join(", ")
-            ));
-        }
-    }
-    gen.line("}");
-
-    // Create the `match` statement, to map from definition to specificity.
-    let mut gen = scope
-        .new_impl("CheckCodePrefix")
-        .new_fn("specificity")
-        .arg_ref_self()
-        .ret(Type::new("SuffixLength"))
-        .vis("pub")
-        .line("#[allow(clippy::match_same_arms)]")
-        .line("match self {");
-    for prefix in prefix_to_codes.keys() {
-        let specificity = if prefix == "ALL" {
-            "None"
-        } else {
-            let num_numeric = prefix.chars().filter(|char| char.is_numeric()).count();
-            match num_numeric {
-                0 => "Zero",
-                1 => "One",
-                2 => "Two",
-                3 => "Three",
-                4 => "Four",
-                _ => panic!("Invalid prefix: {prefix}"),
-            }
-        };
-        gen = gen.line(format!(
-            "CheckCodePrefix::{prefix} => SuffixLength::{specificity},"
-        ));
-    }
-    gen.line("}");
-
-    // Construct the output contents.
-    let mut output = String::new();
-    output
-        .push_str("//! File automatically generated by `examples/generate_check_code_prefix.rs`.");
-    output.push('\n');
-    output.push('\n');
-    output.push_str("use colored::Colorize;");
-    output.push('\n');
-    output.push_str("use schemars::JsonSchema;");
-    output.push('\n');
-    output.push_str("use serde::{Deserialize, Serialize};");
-    output.push('\n');
-    output.push_str("use strum_macros::{AsRefStr, EnumString};");
-    output.push('\n');
-    output.push('\n');
-    output.push_str("use crate::registry::CheckCode;");
-    output.push('\n');
-    output.push_str("use crate::one_time_warning;");
-    output.push('\n');
-    output.push('\n');
-    output.push_str(&scope.to_string());
-    output.push('\n');
-    output.push('\n');
-
-    // Add the list of output categories (not generated).
-    output.push_str("pub const CATEGORIES: &[CheckCodePrefix] = &[");
-    output.push('\n');
-    for prefix in prefix_to_codes.keys() {
-        if prefix.chars().all(char::is_alphabetic)
-            && !PREFIX_REDIRECTS.contains_key(&prefix.as_str())
-        {
-            output.push_str(&format!("CheckCodePrefix::{prefix},"));
-            output.push('\n');
-        }
-    }
-    output.push_str("];");
-    output.push('\n');
-    output.push('\n');
-
-    let rustfmt = Command::new("rustfmt")
-        .stdin(Stdio::piped())
-        .stdout(Stdio::piped())
-        .spawn()?;
-    write!(rustfmt.stdin.as_ref().unwrap(), "{output}")?;
-    let Output { status, stdout, .. } = rustfmt.wait_with_output()?;
-    ensure!(status.success(), "rustfmt failed with {status}");
-
-    // Write the output to `src/registry_gen.rs` (or stdout).
-    if cli.dry_run {
-        println!("{}", String::from_utf8(stdout)?);
-    } else {
-        let file = PathBuf::from(env!("CARGO_MANIFEST_DIR"))
-            .parent()
-            .expect("Failed to find root directory")
-            .join("src/registry_gen.rs");
-        if fs::read(&file).map_or(true, |old| old != stdout) {
-            fs::write(&file, stdout)?;
-        }
-    }
-
-    Ok(())
-}
--- a/ruff_dev/src/generate_cli_help.rs
+++ b/ruff_dev/src/generate_cli_help.rs
@@ -28,7 +28,7 @@ pub fn main(cli: &Cli) -> Result<()> {
        print!("{output}");
    } else {
        replace_readme_section(
-            &format!("```shell\n{output}\n```\n"),
+            &format!("```\n{output}\n```\n"),
            HELP_BEGIN_PRAGMA,
            HELP_END_PRAGMA,
        )?;
--- a/ruff_dev/src/generate_rules_table.rs
+++ b/ruff_dev/src/generate_rules_table.rs
@@ -3,7 +3,7 @@
 use anyhow::Result;
 use clap::Args;
 use itertools::Itertools;
-use ruff::registry::{CheckCategory, CheckCode};
+use ruff::registry::{RuleCode, RuleOrigin};
 use strum::IntoEnumIterator;

 use crate::utils::replace_readme_section;
@@ -25,24 +25,24 @@ pub fn main(cli: &Cli) -> Result<()> {
    // Generate the table string.
    let mut table_out = String::new();
    let mut toc_out = String::new();
-    for check_category in CheckCategory::iter() {
-        let codes_csv: String = check_category.codes().iter().map(AsRef::as_ref).join(", ");
-        table_out.push_str(&format!("### {} ({codes_csv})", check_category.title()));
+    for origin in RuleOrigin::iter() {
+        let codes_csv: String = origin.codes().iter().map(AsRef::as_ref).join(", ");
+        table_out.push_str(&format!("### {} ({codes_csv})", origin.title()));
        table_out.push('\n');
        table_out.push('\n');

        toc_out.push_str(&format!(
            "   1. [{} ({})](#{}-{})\n",
-            check_category.title(),
+            origin.title(),
            codes_csv,
-            check_category.title().to_lowercase().replace(' ', "-"),
+            origin.title().to_lowercase().replace(' ', "-"),
            codes_csv.to_lowercase().replace(',', "-").replace(' ', "")
        ));

-        if let Some((url, platform)) = check_category.url() {
+        if let Some((url, platform)) = origin.url() {
            table_out.push_str(&format!(
                "For more, see [{}]({}) on {}.",
-                check_category.title(),
+                origin.title(),
                url,
                platform
            ));
@@ -55,15 +55,15 @@ pub fn main(cli: &Cli) -> Result<()> {
        table_out.push_str("| ---- | ---- | ------- | --- |");
        table_out.push('\n');

-        for check_code in CheckCode::iter() {
-            if check_code.category() == check_category {
-                let check_kind = check_code.kind();
-                let fix_token = if check_kind.fixable() { "🛠" } else { "" };
+        for rule_code in RuleCode::iter() {
+            if rule_code.origin() == origin {
+                let kind = rule_code.kind();
+                let fix_token = if kind.fixable() { "🛠" } else { "" };
                table_out.push_str(&format!(
                    "| {} | {} | {} | {} |",
-                    check_kind.code().as_ref(),
-                    check_kind.as_ref(),
-                    check_kind.summary().replace('|', r"\|"),
+                    kind.code().as_ref(),
+                    kind.as_ref(),
+                    kind.summary().replace('|', r"\|"),
                    fix_token
                ));
                table_out.push('\n');
--- a/ruff_dev/src/lib.rs
+++ b/ruff_dev/src/lib.rs
@@ -10,9 +10,9 @@
    clippy::similar_names,
    clippy::too_many_lines
 )]
+#![forbid(unsafe_code)]

 pub mod generate_all;
-pub mod generate_check_code_prefix;
 pub mod generate_cli_help;
 pub mod generate_json_schema;
 pub mod generate_options;
--- a/ruff_dev/src/main.rs
+++ b/ruff_dev/src/main.rs
@@ -10,12 +10,13 @@
    clippy::similar_names,
    clippy::too_many_lines
 )]
+#![forbid(unsafe_code)]

 use anyhow::Result;
 use clap::{Parser, Subcommand};
 use ruff_dev::{
-    generate_all, generate_check_code_prefix, generate_cli_help, generate_json_schema,
-    generate_options, generate_rules_table, print_ast, print_cst, print_tokens, round_trip,
+    generate_all, generate_cli_help, generate_json_schema, generate_options, generate_rules_table,
+    print_ast, print_cst, print_tokens, round_trip,
 };

 #[derive(Parser)]
@@ -30,8 +31,6 @@ struct Cli {
 enum Commands {
    /// Run all code and documentation generation steps.
    GenerateAll(generate_all::Cli),
-    /// Generate the `CheckCodePrefix` enum.
-    GenerateCheckCodePrefix(generate_check_code_prefix::Cli),
    /// Generate JSON schema for the TOML configuration file.
    GenerateJSONSchema(generate_json_schema::Cli),
    /// Generate a Markdown-compatible table of supported lint rules.
@@ -54,7 +53,6 @@ fn main() -> Result<()> {
    let cli = Cli::parse();
    match &cli.command {
        Commands::GenerateAll(args) => generate_all::main(args)?,
-        Commands::GenerateCheckCodePrefix(args) => generate_check_code_prefix::main(args)?,
        Commands::GenerateJSONSchema(args) => generate_json_schema::main(args)?,
        Commands::GenerateRulesTable(args) => generate_rules_table::main(args)?,
        Commands::GenerateOptions(args) => generate_options::main(args)?,
--- a/ruff_dev/src/round_trip.rs
+++ b/ruff_dev/src/round_trip.rs
@@ -22,12 +22,8 @@ pub fn main(cli: &Cli) -> Result<()> {
    let python_ast = parser::parse_program(&contents, &cli.file.to_string_lossy())?;
    let locator = SourceCodeLocator::new(&contents);
    let stylist = SourceCodeStyleDetector::from_contents(&contents, &locator);
-    let mut generator = SourceCodeGenerator::new(
-        stylist.indentation(),
-        stylist.quote(),
-        stylist.line_ending(),
-    );
+    let mut generator: SourceCodeGenerator = (&stylist).into();
    generator.unparse_suite(&python_ast);
-    println!("{}", generator.generate()?);
+    println!("{}", generator.generate());
    Ok(())
 }
--- a/ruff_macros/Cargo.toml
+++ b/ruff_macros/Cargo.toml
@@ -1,12 +1,14 @@
 [package]
 name = "ruff_macros"
-version = "0.0.211"
+version = "0.0.219"
 edition = "2021"

 [lib]
 proc-macro = true
+doctest = false

 [dependencies]
+once_cell = { version = "1.17.0" }
 proc-macro2 = { version = "1.0.47" }
 quote = { version = "1.0.21" }
 syn = { version = "1.0.103", features = ["derive", "parsing"] }
--- a/ruff_macros/src/config.rs
+++ b/ruff_macros/src/config.rs
@@ -0,0 +1,203 @@
+use quote::{quote, quote_spanned};
+use syn::parse::{Parse, ParseStream};
+use syn::spanned::Spanned;
+use syn::token::Comma;
+use syn::{
+    AngleBracketedGenericArguments, Attribute, Data, DataStruct, DeriveInput, Field, Fields, Lit,
+    LitStr, Path, PathArguments, PathSegment, Token, Type, TypePath,
+};
+
+pub fn derive_impl(input: DeriveInput) -> syn::Result<proc_macro2::TokenStream> {
+    let DeriveInput { ident, data, .. } = input;
+
+    match data {
+        Data::Struct(DataStruct {
+            fields: Fields::Named(fields),
+            ..
+        }) => {
+            let mut output = vec![];
+
+            for field in fields.named.iter() {
+                let docs: Vec<&Attribute> = field
+                    .attrs
+                    .iter()
+                    .filter(|attr| attr.path.is_ident("doc"))
+                    .collect();
+
+                if docs.is_empty() {
+                    return Err(syn::Error::new(
+                        field.span(),
+                        "Missing documentation for field",
+                    ));
+                }
+
+                if let Some(attr) = field.attrs.iter().find(|attr| attr.path.is_ident("option")) {
+                    output.push(handle_option(field, attr, docs)?);
+                };
+
+                if field
+                    .attrs
+                    .iter()
+                    .any(|attr| attr.path.is_ident("option_group"))
+                {
+                    output.push(handle_option_group(field)?);
+                };
+            }
+
+            Ok(quote! {
+              use crate::settings::options_base::{OptionEntry, OptionField, OptionGroup, ConfigurationOptions};
+
+              #[automatically_derived]
+              impl ConfigurationOptions for #ident {
+                  fn get_available_options() -> Vec<OptionEntry> {
+                      vec![#(#output),*]
+                  }
+              }
+            })
+        }
+        _ => Err(syn::Error::new(
+            ident.span(),
+            "Can only derive ConfigurationOptions from structs with named fields.",
+        )),
+    }
+}
+
+/// For a field with type `Option<Foobar>` where `Foobar` itself is a struct
+/// deriving `ConfigurationOptions`, create code that calls retrieves options
+/// from that group: `Foobar::get_available_options()`
+fn handle_option_group(field: &Field) -> syn::Result<proc_macro2::TokenStream> {
+    let ident = field
+        .ident
+        .as_ref()
+        .expect("Expected to handle named fields");
+
+    match &field.ty {
+        Type::Path(TypePath {
+            path: Path { segments, .. },
+            ..
+        }) => match segments.first() {
+            Some(PathSegment {
+                ident: type_ident,
+                arguments:
+                    PathArguments::AngleBracketed(AngleBracketedGenericArguments { args, .. }),
+                ..
+            }) if type_ident == "Option" => {
+                let path = &args[0];
+                let kebab_name = LitStr::new(&ident.to_string().replace('_', "-"), ident.span());
+
+                Ok(quote_spanned!(
+                    ident.span() => OptionEntry::Group(OptionGroup {
+                        name: #kebab_name,
+                        fields: #path::get_available_options(),
+                    })
+                ))
+            }
+            _ => Err(syn::Error::new(
+                ident.span(),
+                "Expected `Option<_>`  as type.",
+            )),
+        },
+        _ => Err(syn::Error::new(ident.span(), "Expected type.")),
+    }
+}
+
+/// Parse a `doc` attribute into it a string literal.
+fn parse_doc(doc: &Attribute) -> syn::Result<String> {
+    let doc = doc
+        .parse_meta()
+        .map_err(|e| syn::Error::new(doc.span(), e))?;
+
+    match doc {
+        syn::Meta::NameValue(syn::MetaNameValue {
+            lit: Lit::Str(lit_str),
+            ..
+        }) => Ok(lit_str.value()),
+        _ => Err(syn::Error::new(doc.span(), "Expected doc attribute.")),
+    }
+}
+
+/// Parse an `#[option(doc="...", default="...", value_type="...",
+/// example="...")]` attribute and return data in the form of an `OptionField`.
+fn handle_option(
+    field: &Field,
+    attr: &Attribute,
+    docs: Vec<&Attribute>,
+) -> syn::Result<proc_macro2::TokenStream> {
+    // Convert the list of `doc` attributes into a single string.
+    let doc = textwrap::dedent(
+        &docs
+            .into_iter()
+            .map(parse_doc)
+            .collect::<syn::Result<Vec<_>>>()?
+            .join("\n"),
+    )
+    .trim_matches('\n')
+    .to_string();
+
+    let ident = field
+        .ident
+        .as_ref()
+        .expect("Expected to handle named fields");
+
+    let FieldAttributes {
+        default,
+        value_type,
+        example,
+        ..
+    } = attr.parse_args::<FieldAttributes>()?;
+    let kebab_name = LitStr::new(&ident.to_string().replace('_', "-"), ident.span());
+
+    Ok(quote_spanned!(
+        ident.span() => OptionEntry::Field(OptionField {
+            name: #kebab_name,
+            doc: &#doc,
+            default: &#default,
+            value_type: &#value_type,
+            example: &#example,
+        })
+    ))
+}
+
+#[derive(Debug)]
+struct FieldAttributes {
+    default: String,
+    value_type: String,
+    example: String,
+}
+
+impl Parse for FieldAttributes {
+    fn parse(input: ParseStream) -> syn::Result<Self> {
+        let default = _parse_key_value(input, "default")?;
+        input.parse::<Comma>()?;
+        let value_type = _parse_key_value(input, "value_type")?;
+        input.parse::<Comma>()?;
+        let example = _parse_key_value(input, "example")?;
+        if !input.is_empty() {
+            input.parse::<Comma>()?;
+        }
+
+        Ok(FieldAttributes {
+            default,
+            value_type,
+            example: textwrap::dedent(&example).trim_matches('\n').to_string(),
+        })
+    }
+}
+
+fn _parse_key_value(input: ParseStream, name: &str) -> syn::Result<String> {
+    let ident: proc_macro2::Ident = input.parse()?;
+    if ident != name {
+        return Err(syn::Error::new(
+            ident.span(),
+            format!("Expected `{name}` name"),
+        ));
+    }
+
+    input.parse::<Token![=]>()?;
+    let value: Lit = input.parse()?;
+
+    match &value {
+        Lit::Str(v) => Ok(v.value()),
+        _ => Err(syn::Error::new(value.span(), "Expected literal string")),
+    }
+}
--- a/ruff_macros/src/lib.rs
+++ b/ruff_macros/src/lib.rs
@@ -10,216 +10,50 @@
    clippy::similar_names,
    clippy::too_many_lines
 )]
+#![forbid(unsafe_code)]

-use quote::{quote, quote_spanned};
-use syn::parse::{Parse, ParseStream};
-use syn::spanned::Spanned;
-use syn::token::Comma;
-use syn::{
-    parse_macro_input, AngleBracketedGenericArguments, Attribute, Data, DataStruct, DeriveInput,
-    Field, Fields, Lit, LitStr, Path, PathArguments, PathSegment, Token, Type, TypePath,
-};
+use proc_macro2::Span;
+use quote::quote;
+use syn::{parse_macro_input, DeriveInput, Ident};
+
+mod config;
+mod prefixes;
+mod rule_code_prefix;

 #[proc_macro_derive(ConfigurationOptions, attributes(option, doc, option_group))]
-pub fn derive(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
+pub fn derive_config(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
    let input = parse_macro_input!(input as DeriveInput);

-    derive_impl(input)
+    config::derive_impl(input)
        .unwrap_or_else(syn::Error::into_compile_error)
        .into()
 }

-fn derive_impl(input: DeriveInput) -> syn::Result<proc_macro2::TokenStream> {
-    let DeriveInput { ident, data, .. } = input;
+#[proc_macro_derive(RuleCodePrefix)]
+pub fn derive_rule_code_prefix(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
+    let input = parse_macro_input!(input as DeriveInput);

-    match data {
-        Data::Struct(DataStruct {
-            fields: Fields::Named(fields),
-            ..
-        }) => {
-            let mut output = vec![];
+    rule_code_prefix::derive_impl(input)
+        .unwrap_or_else(syn::Error::into_compile_error)
+        .into()
+}

-            for field in fields.named.iter() {
-                let docs: Vec<&Attribute> = field
-                    .attrs
-                    .iter()
-                    .filter(|attr| attr.path.is_ident("doc"))
-                    .collect();
-
-                if docs.is_empty() {
-                    return Err(syn::Error::new(
-                        field.span(),
-                        "Missing documentation for field",
-                    ));
-                }
-
-                if let Some(attr) = field.attrs.iter().find(|attr| attr.path.is_ident("option")) {
-                    output.push(handle_option(field, attr, docs)?);
-                };
-
-                if field
-                    .attrs
-                    .iter()
-                    .any(|attr| attr.path.is_ident("option_group"))
-                {
-                    output.push(handle_option_group(field)?);
-                };
-            }
-
-            Ok(quote! {
-              use crate::settings::options_base::{OptionEntry, OptionField, OptionGroup, ConfigurationOptions};
-
-              #[automatically_derived]
-              impl ConfigurationOptions for #ident {
-                  fn get_available_options() -> Vec<OptionEntry> {
-                      vec![#(#output),*]
-                  }
-              }
-            })
+#[proc_macro]
+pub fn origin_by_code(item: proc_macro::TokenStream) -> proc_macro::TokenStream {
+    let ident = parse_macro_input!(item as Ident).to_string();
+    let mut iter = prefixes::PREFIX_TO_ORIGIN.iter();
+    let origin = loop {
+        let (prefix, origin) = iter
+            .next()
+            .unwrap_or_else(|| panic!("code doesn't start with any recognized prefix: {ident}"));
+        if ident.starts_with(prefix) {
+            break origin;
        }
-        _ => Err(syn::Error::new(
-            ident.span(),
-            "Can only derive ConfigurationOptions from structs with named fields.",
-        )),
-    }
-}
-
-/// For a field with type `Option<Foobar>` where `Foobar` itself is a struct
-/// deriving `ConfigurationOptions`, create code that calls retrieves options
-/// from that group: `Foobar::get_available_options()`
-fn handle_option_group(field: &Field) -> syn::Result<proc_macro2::TokenStream> {
-    let ident = field
-        .ident
-        .as_ref()
-        .expect("Expected to handle named fields");
-
-    match &field.ty {
-        Type::Path(TypePath {
-            path: Path { segments, .. },
-            ..
-        }) => match segments.first() {
-            Some(PathSegment {
-                ident: type_ident,
-                arguments:
-                    PathArguments::AngleBracketed(AngleBracketedGenericArguments { args, .. }),
-                ..
-            }) if type_ident == "Option" => {
-                let path = &args[0];
-                let kebab_name = LitStr::new(&ident.to_string().replace('_', "-"), ident.span());
-
-                Ok(quote_spanned!(
-                    ident.span() => OptionEntry::Group(OptionGroup {
-                        name: #kebab_name,
-                        fields: #path::get_available_options(),
-                    })
-                ))
-            }
-            _ => Err(syn::Error::new(
-                ident.span(),
-                "Expected `Option<_>`  as type.",
-            )),
-        },
-        _ => Err(syn::Error::new(ident.span(), "Expected type.")),
-    }
-}
-
-/// Parse a `doc` attribute into it a string literal.
-fn parse_doc(doc: &Attribute) -> syn::Result<String> {
-    let doc = doc
-        .parse_meta()
-        .map_err(|e| syn::Error::new(doc.span(), e))?;
-
-    match doc {
-        syn::Meta::NameValue(syn::MetaNameValue {
-            lit: Lit::Str(lit_str),
-            ..
-        }) => Ok(lit_str.value()),
-        _ => Err(syn::Error::new(doc.span(), "Expected doc attribute.")),
-    }
-}
-
-/// Parse an `#[option(doc="...", default="...", value_type="...",
-/// example="...")]` attribute and return data in the form of an `OptionField`.
-fn handle_option(
-    field: &Field,
-    attr: &Attribute,
-    docs: Vec<&Attribute>,
-) -> syn::Result<proc_macro2::TokenStream> {
-    // Convert the list of `doc` attributes into a single string.
-    let doc = textwrap::dedent(
-        &docs
-            .into_iter()
-            .map(parse_doc)
-            .collect::<syn::Result<Vec<_>>>()?
-            .join("\n"),
-    )
-    .trim_matches('\n')
-    .to_string();
-
-    let ident = field
-        .ident
-        .as_ref()
-        .expect("Expected to handle named fields");
-
-    let FieldAttributes {
-        default,
-        value_type,
-        example,
-        ..
-    } = attr.parse_args::<FieldAttributes>()?;
-    let kebab_name = LitStr::new(&ident.to_string().replace('_', "-"), ident.span());
-
-    Ok(quote_spanned!(
-        ident.span() => OptionEntry::Field(OptionField {
-            name: #kebab_name,
-            doc: &#doc,
-            default: &#default,
-            value_type: &#value_type,
-            example: &#example,
-        })
-    ))
-}
-
-#[derive(Debug)]
-struct FieldAttributes {
-    default: String,
-    value_type: String,
-    example: String,
-}
-
-impl Parse for FieldAttributes {
-    fn parse(input: ParseStream) -> syn::Result<Self> {
-        let default = _parse_key_value(input, "default")?;
-        input.parse::<Comma>()?;
-        let value_type = _parse_key_value(input, "value_type")?;
-        input.parse::<Comma>()?;
-        let example = _parse_key_value(input, "example")?;
-        if !input.is_empty() {
-            input.parse::<Comma>()?;
-        }
-
-        Ok(FieldAttributes {
-            default,
-            value_type,
-            example: textwrap::dedent(&example).trim_matches('\n').to_string(),
-        })
-    }
-}
-
-fn _parse_key_value(input: ParseStream, name: &str) -> syn::Result<String> {
-    let ident: proc_macro2::Ident = input.parse()?;
-    if ident != name {
-        return Err(syn::Error::new(
-            ident.span(),
-            format!("Expected `{name}` name"),
-        ));
-    }
-
-    input.parse::<Token![=]>()?;
-    let value: Lit = input.parse()?;
-
-    match &value {
-        Lit::Str(v) => Ok(v.value()),
-        _ => Err(syn::Error::new(value.span(), "Expected literal string")),
+    };
+    let prefix = Ident::new(origin, Span::call_site());
+
+    quote! {
+        RuleOrigin::#prefix
    }
+    .into()
 }
--- a/ruff_macros/src/prefixes.rs
+++ b/ruff_macros/src/prefixes.rs
@@ -0,0 +1,53 @@
+// Longer prefixes should come first so that you can find an origin for a code
+// by simply picking the first entry that starts with the given prefix.
+
+pub const PREFIX_TO_ORIGIN: &[(&str, &str)] = &[
+    ("ANN", "Flake8Annotations"),
+    ("ARG", "Flake8UnusedArguments"),
+    ("A", "Flake8Builtins"),
+    ("BLE", "Flake8BlindExcept"),
+    ("B", "Flake8Bugbear"),
+    ("C4", "Flake8Comprehensions"),
+    ("C9", "McCabe"),
+    ("DTZ", "Flake8Datetimez"),
+    ("D", "Pydocstyle"),
+    ("ERA", "Eradicate"),
+    ("EM", "Flake8ErrMsg"),
+    ("E", "Pycodestyle"),
+    ("FBT", "Flake8BooleanTrap"),
+    ("F", "Pyflakes"),
+    ("ICN", "Flake8ImportConventions"),
+    ("ISC", "Flake8ImplicitStrConcat"),
+    ("I", "Isort"),
+    ("N", "PEP8Naming"),
+    ("PD", "PandasVet"),
+    ("PGH", "PygrepHooks"),
+    ("PL", "Pylint"),
+    ("PT", "Flake8PytestStyle"),
+    ("Q", "Flake8Quotes"),
+    ("RET", "Flake8Return"),
+    ("SIM", "Flake8Simplify"),
+    ("S", "Flake8Bandit"),
+    ("T10", "Flake8Debugger"),
+    ("T20", "Flake8Print"),
+    ("TID", "Flake8TidyImports"),
+    ("UP", "Pyupgrade"),
+    ("W", "Pycodestyle"),
+    ("YTT", "Flake82020"),
+    ("PIE", "Flake8Pie"),
+    ("RUF", "Ruff"),
+];
+
+#[cfg(test)]
+mod tests {
+    use super::PREFIX_TO_ORIGIN;
+
+    #[test]
+    fn order() {
+        for (idx, (prefix, _)) in PREFIX_TO_ORIGIN.iter().enumerate() {
+            for (prior_prefix, _) in PREFIX_TO_ORIGIN[..idx].iter() {
+                assert!(!prefix.starts_with(prior_prefix));
+            }
+        }
+    }
+}
--- a/ruff_macros/src/rule_code_prefix.rs
+++ b/ruff_macros/src/rule_code_prefix.rs
@@ -0,0 +1,287 @@
+use std::collections::{BTreeMap, BTreeSet, HashMap};
+
+use once_cell::sync::Lazy;
+use proc_macro2::Span;
+use quote::quote;
+use syn::punctuated::Punctuated;
+use syn::token::Comma;
+use syn::{DataEnum, DeriveInput, Ident, Variant};
+
+const ALL: &str = "ALL";
+
+/// A hash map from deprecated `RuleCodePrefix` to latest
+/// `RuleCodePrefix`.
+pub static PREFIX_REDIRECTS: Lazy<HashMap<&'static str, &'static str>> = Lazy::new(|| {
+    HashMap::from_iter([
+        // TODO(charlie): Remove by 2023-01-01.
+        ("U001", "UP001"),
+        ("U003", "UP003"),
+        ("U004", "UP004"),
+        ("U005", "UP005"),
+        ("U006", "UP006"),
+        ("U007", "UP007"),
+        ("U008", "UP008"),
+        ("U009", "UP009"),
+        ("U010", "UP010"),
+        ("U011", "UP011"),
+        ("U012", "UP012"),
+        ("U013", "UP013"),
+        ("U014", "UP014"),
+        ("U015", "UP015"),
+        ("U016", "UP016"),
+        ("U017", "UP017"),
+        ("U019", "UP019"),
+        // TODO(charlie): Remove by 2023-02-01.
+        ("I252", "TID252"),
+        ("M001", "RUF100"),
+        // TODO(charlie): Remove by 2023-02-01.
+        ("PDV002", "PD002"),
+        ("PDV003", "PD003"),
+        ("PDV004", "PD004"),
+        ("PDV007", "PD007"),
+        ("PDV008", "PD008"),
+        ("PDV009", "PD009"),
+        ("PDV010", "PD010"),
+        ("PDV011", "PD011"),
+        ("PDV012", "PD012"),
+        ("PDV013", "PD013"),
+        ("PDV015", "PD015"),
+        ("PDV901", "PD901"),
+        // TODO(charlie): Remove by 2023-02-01.
+        ("R501", "RET501"),
+        ("R502", "RET502"),
+        ("R503", "RET503"),
+        ("R504", "RET504"),
+        ("R505", "RET505"),
+        ("R506", "RET506"),
+        ("R507", "RET507"),
+        ("R508", "RET508"),
+        ("IC001", "ICN001"),
+        ("IC002", "ICN001"),
+        ("IC003", "ICN001"),
+        ("IC004", "ICN001"),
+        // TODO(charlie): Remove by 2023-01-01.
+        ("U", "UP"),
+        ("U0", "UP0"),
+        ("U00", "UP00"),
+        ("U01", "UP01"),
+        // TODO(charlie): Remove by 2023-02-01.
+        ("I2", "TID2"),
+        ("I25", "TID25"),
+        ("M", "RUF100"),
+        ("M0", "RUF100"),
+        // TODO(charlie): Remove by 2023-02-01.
+        ("PDV", "PD"),
+        ("PDV0", "PD0"),
+        ("PDV01", "PD01"),
+        ("PDV9", "PD9"),
+        ("PDV90", "PD90"),
+        // TODO(charlie): Remove by 2023-02-01.
+        ("R", "RET"),
+        ("R5", "RET5"),
+        ("R50", "RET50"),
+        // TODO(charlie): Remove by 2023-02-01.
+        ("IC", "ICN"),
+        ("IC0", "ICN0"),
+    ])
+});
+
+pub fn derive_impl(input: DeriveInput) -> syn::Result<proc_macro2::TokenStream> {
+    let DeriveInput { ident, data, .. } = input;
+    let syn::Data::Enum(DataEnum { variants, .. }) = data else {
+        return Err(syn::Error::new(
+            ident.span(),
+            "Can only derive `RuleCodePrefix` from enums.",
+        ));
+    };
+
+    let prefix_ident = Ident::new(&format!("{ident}Prefix"), ident.span());
+    let prefix = expand(&ident, &prefix_ident, &variants);
+    let expanded = quote! {
+        #[derive(PartialEq, Eq, PartialOrd, Ord)]
+        pub enum SuffixLength {
+            None,
+            Zero,
+            One,
+            Two,
+            Three,
+            Four,
+        }
+
+        #prefix
+    };
+    Ok(expanded)
+}
+
+fn expand(
+    ident: &Ident,
+    prefix_ident: &Ident,
+    variants: &Punctuated<Variant, Comma>,
+) -> proc_macro2::TokenStream {
+    // Build up a map from prefix to matching RuleCodes.
+    let mut prefix_to_codes: BTreeMap<Ident, BTreeSet<String>> = BTreeMap::default();
+    for variant in variants {
+        let span = variant.ident.span();
+        let code_str = variant.ident.to_string();
+        let code_prefix_len = code_str
+            .chars()
+            .take_while(|char| char.is_alphabetic())
+            .count();
+        let code_suffix_len = code_str.len() - code_prefix_len;
+        for i in 0..=code_suffix_len {
+            let prefix = code_str[..code_prefix_len + i].to_string();
+            prefix_to_codes
+                .entry(Ident::new(&prefix, span))
+                .or_default()
+                .insert(code_str.clone());
+        }
+        prefix_to_codes
+            .entry(Ident::new(ALL, span))
+            .or_default()
+            .insert(code_str.clone());
+    }
+
+    // Add any prefix aliases (e.g., "U" to "UP").
+    for (alias, rule_code) in PREFIX_REDIRECTS.iter() {
+        prefix_to_codes.insert(
+            Ident::new(alias, Span::call_site()),
+            prefix_to_codes
+                .get(&Ident::new(rule_code, Span::call_site()))
+                .unwrap_or_else(|| panic!("Unknown RuleCode: {alias:?}"))
+                .clone(),
+        );
+    }
+
+    let prefix_variants = prefix_to_codes.keys().map(|prefix| {
+        quote! {
+            #prefix
+        }
+    });
+
+    let prefix_impl = generate_impls(ident, prefix_ident, &prefix_to_codes);
+
+    let prefix_redirects = PREFIX_REDIRECTS.iter().map(|(alias, rule_code)| {
+        let code = Ident::new(rule_code, Span::call_site());
+        quote! {
+            (#alias, #prefix_ident::#code)
+        }
+    });
+
+    quote! {
+        #[derive(
+            ::strum_macros::EnumString,
+            ::strum_macros::AsRefStr,
+            Debug,
+            PartialEq,
+            Eq,
+            PartialOrd,
+            Ord,
+            Clone,
+            ::serde::Serialize,
+            ::serde::Deserialize,
+            ::schemars::JsonSchema,
+        )]
+        pub enum #prefix_ident {
+            #(#prefix_variants,)*
+        }
+
+        #prefix_impl
+
+        /// A hash map from deprecated `RuleCodePrefix` to latest `RuleCodePrefix`.
+        pub static PREFIX_REDIRECTS: ::once_cell::sync::Lazy<::rustc_hash::FxHashMap<&'static str, #prefix_ident>> = ::once_cell::sync::Lazy::new(|| {
+            ::rustc_hash::FxHashMap::from_iter([
+                #(#prefix_redirects),*
+            ])
+        });
+    }
+}
+
+fn generate_impls(
+    ident: &Ident,
+    prefix_ident: &Ident,
+    prefix_to_codes: &BTreeMap<Ident, BTreeSet<String>>,
+) -> proc_macro2::TokenStream {
+    let codes_match_arms = prefix_to_codes.iter().map(|(prefix, codes)| {
+        let codes = codes.iter().map(|code| {
+            let code = Ident::new(code, Span::call_site());
+            quote! {
+                #ident::#code
+            }
+        });
+        let prefix_str = prefix.to_string();
+        if let Some(target) = PREFIX_REDIRECTS.get(prefix_str.as_str()) {
+            quote! {
+                #prefix_ident::#prefix => {
+                    crate::warn_user_once!(
+                        "`{}` has been remapped to `{}`", #prefix_str, #target
+                    );
+                    vec![#(#codes),*]
+                }
+            }
+        } else {
+            quote! {
+                #prefix_ident::#prefix => vec![#(#codes),*],
+            }
+        }
+    });
+
+    let specificity_match_arms = prefix_to_codes.keys().map(|prefix| {
+        if *prefix == ALL {
+            quote! {
+                #prefix_ident::#prefix => SuffixLength::None,
+            }
+        } else {
+            let num_numeric = prefix
+                .to_string()
+                .chars()
+                .filter(|char| char.is_numeric())
+                .count();
+            let suffix_len = match num_numeric {
+                0 => quote! { SuffixLength::Zero },
+                1 => quote! { SuffixLength::One },
+                2 => quote! { SuffixLength::Two },
+                3 => quote! { SuffixLength::Three },
+                4 => quote! { SuffixLength::Four },
+                _ => panic!("Invalid prefix: {prefix}"),
+            };
+            quote! {
+                #prefix_ident::#prefix => #suffix_len,
+            }
+        }
+    });
+
+    let categories = prefix_to_codes.keys().map(|prefix| {
+        let prefix_str = prefix.to_string();
+        if prefix_str.chars().all(char::is_alphabetic)
+            && !PREFIX_REDIRECTS.contains_key(&prefix_str.as_str())
+        {
+            quote! {
+                #prefix_ident::#prefix,
+            }
+        } else {
+            quote! {}
+        }
+    });
+
+    quote! {
+        impl #prefix_ident {
+            pub fn codes(&self) -> Vec<#ident> {
+                use colored::Colorize;
+
+                #[allow(clippy::match_same_arms)]
+                match self {
+                    #(#codes_match_arms)*
+                }
+            }
+
+            pub fn specificity(&self) -> SuffixLength {
+                #[allow(clippy::match_same_arms)]
+                match self {
+                    #(#specificity_match_arms)*
+                }
+            }
+        }
+
+        pub const CATEGORIES: &[#prefix_ident] = &[#(#categories)*];
+    }
+}
--- a/scripts/add_check.py
+++ b/scripts/add_check.py
@@ -1,139 +0,0 @@
-#!/usr/bin/env python3
-"""Generate boilerplate for a new check.
-
-Example usage:
-
-    python scripts/add_check.py \
-        --name PreferListBuiltin \
-        --code PIE807 \
-        --plugin flake8-pie
-"""
-
-import argparse
-import os
-
-ROOT_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
-
-
-def dir_name(plugin: str) -> str:
-    return plugin.replace("-", "_")
-
-
-def pascal_case(plugin: str) -> str:
-    """Convert from snake-case to PascalCase."""
-    return "".join(word.title() for word in plugin.split("-"))
-
-
-def snake_case(name: str) -> str:
-    """Convert from PascalCase to snake_case."""
-    return "".join(f"_{word.lower()}" if word.isupper() else word for word in name).lstrip("_")
-
-
-def main(*, name: str, code: str, plugin: str) -> None:
-    # Create a test fixture.
-    with open(
-        os.path.join(ROOT_DIR, f"resources/test/fixtures/{dir_name(plugin)}/{code}.py"),
-        "a",
-    ):
-        pass
-
-    # Add the relevant `#testcase` macro.
-    with open(os.path.join(ROOT_DIR, f"src/{dir_name(plugin)}/mod.rs"), "r") as fp:
-        content = fp.read()
-
-    with open(os.path.join(ROOT_DIR, f"src/{dir_name(plugin)}/mod.rs"), "w") as fp:
-        for line in content.splitlines():
-            if line.strip() == "fn checks(check_code: CheckCode, path: &Path) -> Result<()> {":
-                indent = line.split("fn checks(check_code: CheckCode, path: &Path) -> Result<()> {")[0]
-                fp.write(f'{indent}#[test_case(CheckCode::{code}, Path::new("{code}.py"); "{code}")]')
-                fp.write("\n")
-
-            fp.write(line)
-            fp.write("\n")
-
-    # Add the relevant plugin function.
-    with open(os.path.join(ROOT_DIR, f"src/{dir_name(plugin)}/plugins.rs"), "a") as fp:
-        fp.write(
-            f"""
-/// {code}
-pub fn {snake_case(name)}(checker: &mut Checker) {{}}
-"""
-        )
-        fp.write("\n")
-
-    # Add the relevant sections to `src/registry.rs`.
-    with open(os.path.join(ROOT_DIR, "src/registry.rs"), "r") as fp:
-        content = fp.read()
-
-    index = 0
-    with open(os.path.join(ROOT_DIR, "src/registry.rs"), "w") as fp:
-        for line in content.splitlines():
-            fp.write(line)
-            fp.write("\n")
-
-            if line.strip() == f"// {plugin}":
-                if index == 0:
-                    # `CheckCode` definition
-                    indent = line.split(f"// {plugin}")[0]
-                    fp.write(f"{indent}{code},")
-                    fp.write("\n")
-
-                elif index == 1:
-                    # `CheckKind` definition
-                    indent = line.split(f"// {plugin}")[0]
-                    fp.write(f"{indent}{name},")
-                    fp.write("\n")
-
-                elif index == 2:
-                    # `CheckCode#kind()`
-                    indent = line.split(f"// {plugin}")[0]
-                    fp.write(f"{indent}CheckCode::{code} => CheckKind::{name},")
-                    fp.write("\n")
-
-                elif index == 3:
-                    # `CheckCode#category()`
-                    indent = line.split(f"// {plugin}")[0]
-                    fp.write(f"{indent}CheckCode::{code} => CheckCategory::{pascal_case(plugin)},")
-                    fp.write("\n")
-
-                elif index == 4:
-                    # `CheckKind#code()`
-                    indent = line.split(f"// {plugin}")[0]
-                    fp.write(f"{indent}CheckKind::{name} => &CheckCode::{code},")
-                    fp.write("\n")
-
-                elif index == 5:
-                    # `CheckCode#body`
-                    indent = line.split(f"// {plugin}")[0]
-                    fp.write(f'{indent}CheckKind::{name} => todo!("Write message body for {code}"),')
-                    fp.write("\n")
-
-                index += 1
-
-
-if __name__ == "__main__":
-    parser = argparse.ArgumentParser(
-        description="Generate boilerplate for a new check.",
-        epilog="python scripts/add_check.py --name PreferListBuiltin --code PIE807 --plugin flake8-pie",
-    )
-    parser.add_argument(
-        "--name",
-        type=str,
-        required=True,
-        help="The name of the check to generate, in PascalCase (e.g., 'LineTooLong').",
-    )
-    parser.add_argument(
-        "--code",
-        type=str,
-        required=True,
-        help="The code of the check to generate (e.g., 'A001').",
-    )
-    parser.add_argument(
-        "--plugin",
-        type=str,
-        required=True,
-        help="The plugin with which the check is associated (e.g., 'flake8-builtins').",
-    )
-    args = parser.parse_args()
-
-    main(name=args.name, code=args.code, plugin=args.plugin)
--- a/scripts/add_plugin.py
+++ b/scripts/add_plugin.py
@@ -1,5 +1,5 @@
 #!/usr/bin/env python3
-"""Generate boilerplate for a new plugin.
+"""Generate boilerplate for a new Flake8 plugin.

 Example usage:

@@ -31,10 +31,10 @@ def main(*, plugin: str, url: str) -> None:

    # Create the Rust module.
    os.makedirs(os.path.join(ROOT_DIR, f"src/{dir_name(plugin)}"), exist_ok=True)
-    with open(os.path.join(ROOT_DIR, f"src/{dir_name(plugin)}/plugins.rs"), "a"):
-        pass
+    with open(os.path.join(ROOT_DIR, f"src/{dir_name(plugin)}/rules.rs"), "w+") as fp:
+        fp.write("use crate::checkers::ast::Checker;\n")
    with open(os.path.join(ROOT_DIR, f"src/{dir_name(plugin)}/mod.rs"), "w+") as fp:
-        fp.write("pub mod plugins;\n")
+        fp.write("pub mod rules;\n")
        fp.write("\n")
        fp.write(
            """#[cfg(test)]
@@ -45,19 +45,19 @@ mod tests {
    use anyhow::Result;
    use test_case::test_case;

-    use crate::registry::CheckCode;
+    use crate::registry::RuleCode;
    use crate::linter::test_path;
    use crate::settings;

-    fn checks(check_code: CheckCode, path: &Path) -> Result<()> {
-        let snapshot = format!("{}_{}", check_code.as_ref(), path.to_string_lossy());
-        let checks = test_path(
+    fn rules(rule_code: RuleCode, path: &Path) -> Result<()> {
+        let snapshot = format!("{}_{}", rule_code.as_ref(), path.to_string_lossy());
+        let diagnostics =test_path(
            Path::new("./resources/test/fixtures/%s")
                .join(path)
                .as_path(),
-            &settings::Settings::for_rule(check_code),
+            &settings::Settings::for_rule(rule_code),
        )?;
-        insta::assert_yaml_snapshot!(snapshot, checks);
+        insta::assert_yaml_snapshot!(snapshot, diagnostics);
        Ok(())
    }
 }
@@ -67,10 +67,10 @@ mod tests {

    # Add the plugin to `lib.rs`.
    with open(os.path.join(ROOT_DIR, "src/lib.rs"), "a") as fp:
-        fp.write(f"pub mod {dir_name(plugin)};")
+        fp.write(f"mod {dir_name(plugin)};")

    # Add the relevant sections to `src/registry.rs`.
-    with open(os.path.join(ROOT_DIR, "src/registry.rs"), "r") as fp:
+    with open(os.path.join(ROOT_DIR, "src/registry.rs")) as fp:
        content = fp.read()

    with open(os.path.join(ROOT_DIR, "src/registry.rs"), "w") as fp:
@@ -85,23 +85,37 @@ mod tests {
                fp.write(f"{indent}{pascal_case(plugin)},")
                fp.write("\n")

-            elif line.strip() == 'CheckCategory::Ruff => "Ruff-specific rules",':
-                indent = line.split('CheckCategory::Ruff => "Ruff-specific rules",')[0]
-                fp.write(f'{indent}CheckCategory::{pascal_case(plugin)} => "{plugin}",')
+            elif line.strip() == 'RuleOrigin::Ruff => "Ruff-specific rules",':
+                indent = line.split('RuleOrigin::Ruff => "Ruff-specific rules",')[0]
+                fp.write(f'{indent}RuleOrigin::{pascal_case(plugin)} => "{plugin}",')
                fp.write("\n")

-            elif line.strip() == "CheckCategory::Ruff => vec![CheckCodePrefix::RUF],":
-                indent = line.split("CheckCategory::Ruff => vec![CheckCodePrefix::RUF],")[0]
+            elif line.strip() == "RuleOrigin::Ruff => vec![RuleCodePrefix::RUF],":
+                indent = line.split("RuleOrigin::Ruff => vec![RuleCodePrefix::RUF],")[0]
                fp.write(
-                    f"{indent}CheckCategory::{pascal_case(plugin)} => vec![\n"
+                    f"{indent}RuleOrigin::{pascal_case(plugin)} => vec![\n"
                    f'{indent}    todo!("Fill-in prefix after generating codes")\n'
                    f"{indent}],"
                )
                fp.write("\n")

-            elif line.strip() == "CheckCategory::Ruff => None,":
-                indent = line.split("CheckCategory::Ruff => None,")[0]
-                fp.write(f"{indent}CheckCategory::{pascal_case(plugin)} => " f'Some(("{url}", &Platform::PyPI)),')
+            elif line.strip() == "RuleOrigin::Ruff => None,":
+                indent = line.split("RuleOrigin::Ruff => None,")[0]
+                fp.write(f"{indent}RuleOrigin::{pascal_case(plugin)} => " f'Some(("{url}", &Platform::PyPI)),')
+                fp.write("\n")
+
+            fp.write(line)
+            fp.write("\n")
+
+    # Add the relevant section to `src/violations.rs`.
+    with open(os.path.join(ROOT_DIR, "src/violations.rs")) as fp:
+        content = fp.read()
+
+    with open(os.path.join(ROOT_DIR, "src/violations.rs"), "w") as fp:
+        for line in content.splitlines():
+            if line.strip() == "// Ruff":
+                indent = line.split("// Ruff")[0]
+                fp.write(f"{indent}// {plugin}")
                fp.write("\n")

            fp.write(line)
@@ -110,7 +124,7 @@ mod tests {

 if __name__ == "__main__":
    parser = argparse.ArgumentParser(
-        description="Generate boilerplate for a new plugin.",
+        description="Generate boilerplate for a new Flake8 plugin.",
        epilog=(
            "Example usage: python scripts/add_plugin.py flake8-pie "
            "--url https://pypi.org/project/flake8-pie/0.16.0/"
@@ -118,7 +132,6 @@ if __name__ == "__main__":
    )
    parser.add_argument(
        "plugin",
-        required=True,
        type=str,
        help="The name of the plugin to generate.",
    )
--- a/scripts/add_rule.py
+++ b/scripts/add_rule.py
@@ -0,0 +1,145 @@
+#!/usr/bin/env python3
+"""Generate boilerplate for a new rule.
+
+Example usage:
+
+    python scripts/add_rule.py \
+        --name PreferListBuiltin \
+        --code PIE807 \
+        --origin flake8-pie
+"""
+
+import argparse
+import os
+
+ROOT_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+
+
+def dir_name(origin: str) -> str:
+    return origin.replace("-", "_")
+
+
+def pascal_case(origin: str) -> str:
+    """Convert from snake-case to PascalCase."""
+    return "".join(word.title() for word in origin.split("-"))
+
+
+def snake_case(name: str) -> str:
+    """Convert from PascalCase to snake_case."""
+    return "".join(f"_{word.lower()}" if word.isupper() else word for word in name).lstrip("_")
+
+
+def main(*, name: str, code: str, origin: str) -> None:
+    # Create a test fixture.
+    with open(
+        os.path.join(ROOT_DIR, f"resources/test/fixtures/{dir_name(origin)}/{code}.py"),
+        "a",
+    ):
+        pass
+
+    # Add the relevant `#testcase` macro.
+    with open(os.path.join(ROOT_DIR, f"src/{dir_name(origin)}/mod.rs")) as fp:
+        content = fp.read()
+
+    with open(os.path.join(ROOT_DIR, f"src/{dir_name(origin)}/mod.rs"), "w") as fp:
+        for line in content.splitlines():
+            if line.strip() == "fn rules(rule_code: RuleCode, path: &Path) -> Result<()> {":
+                indent = line.split("fn rules(rule_code: RuleCode, path: &Path) -> Result<()> {")[0]
+                fp.write(f'{indent}#[test_case(RuleCode::{code}, Path::new("{code}.py"); "{code}")]')
+                fp.write("\n")
+
+            fp.write(line)
+            fp.write("\n")
+
+    # Add the relevant rule function.
+    with open(os.path.join(ROOT_DIR, f"src/{dir_name(origin)}/rules.rs"), "a") as fp:
+        fp.write(
+            f"""
+/// {code}
+pub fn {snake_case(name)}(checker: &mut Checker) {{}}
+"""
+        )
+        fp.write("\n")
+
+    # Add the relevant struct to `src/violations.rs`.
+    with open(os.path.join(ROOT_DIR, "src/violations.rs")) as fp:
+        content = fp.read()
+
+    with open(os.path.join(ROOT_DIR, "src/violations.rs"), "w") as fp:
+        for line in content.splitlines():
+            fp.write(line)
+            fp.write("\n")
+
+            if line.startswith(f"// {origin}"):
+                fp.write(
+                    """define_violation!(
+    pub struct %s;
+);
+impl Violation for %s {
+    fn message(&self) -> String {
+        todo!("Implement message")
+    }
+
+    fn placeholder() -> Self {
+        %s
+    }
+}
+"""
+                    % (name, name, name)
+                )
+                fp.write("\n")
+
+    # Add the relevant code-to-violation pair to `src/registry.rs`.
+    with open(os.path.join(ROOT_DIR, "src/registry.rs")) as fp:
+        content = fp.read()
+
+    seen_macro = False
+    has_written = False
+    with open(os.path.join(ROOT_DIR, "src/registry.rs"), "w") as fp:
+        for line in content.splitlines():
+            fp.write(line)
+            fp.write("\n")
+
+            if has_written:
+                continue
+
+            if line.startswith("define_rule_mapping!"):
+                seen_macro = True
+                continue
+
+            if not seen_macro:
+                continue
+
+            if line.strip() == f"// {origin}":
+                indent = line.split("//")[0]
+                fp.write(f"{indent}{code} => violations::{name},")
+                fp.write("\n")
+                has_written = True
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(
+        description="Generate boilerplate for a new rule.",
+        epilog="python scripts/add_rule.py --name PreferListBuiltin --code PIE807 --origin flake8-pie",
+    )
+    parser.add_argument(
+        "--name",
+        type=str,
+        required=True,
+        help="The name of the check to generate, in PascalCase (e.g., 'LineTooLong').",
+    )
+    parser.add_argument(
+        "--code",
+        type=str,
+        required=True,
+        help="The code of the check to generate (e.g., 'A001').",
+    )
+    parser.add_argument(
+        "--origin",
+        type=str,
+        required=True,
+        help="The source with which the check originated (e.g., 'flake8-builtins').",
+    )
+    args = parser.parse_args()
+
+    main(name=args.name, code=args.code, origin=args.origin)
--- a/src/ast/branch_detection.rs
+++ b/src/ast/branch_detection.rs
@@ -52,8 +52,8 @@ fn common_ancestor<'a>(
 }

 /// Return the alternative branches for a given node.
-fn alternatives<'a>(node: &'a RefEquality<'a, Stmt>) -> Vec<Vec<RefEquality<'a, Stmt>>> {
-    match &node.0.node {
+fn alternatives<'a>(stmt: &'a RefEquality<'a, Stmt>) -> Vec<Vec<RefEquality<'a, Stmt>>> {
+    match &stmt.node {
        StmtKind::If { body, .. } => vec![body.iter().map(RefEquality).collect()],
        StmtKind::Try {
            body,
@@ -71,16 +71,16 @@ fn alternatives<'a>(node: &'a RefEquality<'a, Stmt>) -> Vec<Vec<RefEquality<'a,
    }
 }

-/// Return `true` if `node` is a descendent of any of the nodes in `ancestors`.
+/// Return `true` if `stmt` is a descendent of any of the nodes in `ancestors`.
 fn descendant_of<'a>(
-    node: &RefEquality<'a, Stmt>,
+    stmt: &RefEquality<'a, Stmt>,
    ancestors: &[RefEquality<'a, Stmt>],
    stop: &RefEquality<'a, Stmt>,
    depths: &FxHashMap<RefEquality<'a, Stmt>, usize>,
    child_to_parent: &FxHashMap<RefEquality<'a, Stmt>, RefEquality<'a, Stmt>>,
 ) -> bool {
    ancestors.iter().any(|ancestor| {
-        common_ancestor(node, ancestor, Some(stop), depths, child_to_parent).is_some()
+        common_ancestor(stmt, ancestor, Some(stop), depths, child_to_parent).is_some()
    })
 }

--- a/src/ast/cast.rs
+++ b/src/ast/cast.rs
@@ -1,5 +1,12 @@
 use rustpython_ast::{Expr, Stmt, StmtKind};

+pub fn name(stmt: &Stmt) -> &str {
+    match &stmt.node {
+        StmtKind::FunctionDef { name, .. } | StmtKind::AsyncFunctionDef { name, .. } => name,
+        _ => panic!("Expected StmtKind::FunctionDef | StmtKind::AsyncFunctionDef"),
+    }
+}
+
 pub fn decorator_list(stmt: &Stmt) -> &Vec<Expr> {
    match &stmt.node {
        StmtKind::FunctionDef { decorator_list, .. }
--- a/src/ast/comparable.rs
+++ b/src/ast/comparable.rs
@@ -0,0 +1,530 @@
+//! An equivalent object hierarchy to the `Expr` hierarchy, but with the ability
+//! to compare expressions for equality (via `Eq` and `Hash`).
+
+use num_bigint::BigInt;
+use rustpython_ast::{
+    Arg, Arguments, Boolop, Cmpop, Comprehension, Constant, Expr, ExprContext, ExprKind, Keyword,
+    Operator, Unaryop,
+};
+
+#[derive(Debug, PartialEq, Eq, Hash)]
+pub enum ComparableExprContext {
+    Load,
+    Store,
+    Del,
+}
+
+impl From<&ExprContext> for ComparableExprContext {
+    fn from(ctx: &ExprContext) -> Self {
+        match ctx {
+            ExprContext::Load => Self::Load,
+            ExprContext::Store => Self::Store,
+            ExprContext::Del => Self::Del,
+        }
+    }
+}
+
+#[derive(Debug, PartialEq, Eq, Hash)]
+pub enum ComparableBoolop {
+    And,
+    Or,
+}
+
+impl From<&Boolop> for ComparableBoolop {
+    fn from(op: &Boolop) -> Self {
+        match op {
+            Boolop::And => Self::And,
+            Boolop::Or => Self::Or,
+        }
+    }
+}
+
+#[derive(Debug, PartialEq, Eq, Hash)]
+pub enum ComparableOperator {
+    Add,
+    Sub,
+    Mult,
+    MatMult,
+    Div,
+    Mod,
+    Pow,
+    LShift,
+    RShift,
+    BitOr,
+    BitXor,
+    BitAnd,
+    FloorDiv,
+}
+
+impl From<&Operator> for ComparableOperator {
+    fn from(op: &Operator) -> Self {
+        match op {
+            Operator::Add => Self::Add,
+            Operator::Sub => Self::Sub,
+            Operator::Mult => Self::Mult,
+            Operator::MatMult => Self::MatMult,
+            Operator::Div => Self::Div,
+            Operator::Mod => Self::Mod,
+            Operator::Pow => Self::Pow,
+            Operator::LShift => Self::LShift,
+            Operator::RShift => Self::RShift,
+            Operator::BitOr => Self::BitOr,
+            Operator::BitXor => Self::BitXor,
+            Operator::BitAnd => Self::BitAnd,
+            Operator::FloorDiv => Self::FloorDiv,
+        }
+    }
+}
+
+#[derive(Debug, PartialEq, Eq, Hash)]
+pub enum ComparableUnaryop {
+    Invert,
+    Not,
+    UAdd,
+    USub,
+}
+
+impl From<&Unaryop> for ComparableUnaryop {
+    fn from(op: &Unaryop) -> Self {
+        match op {
+            Unaryop::Invert => Self::Invert,
+            Unaryop::Not => Self::Not,
+            Unaryop::UAdd => Self::UAdd,
+            Unaryop::USub => Self::USub,
+        }
+    }
+}
+
+#[derive(Debug, PartialEq, Eq, Hash)]
+pub enum ComparableCmpop {
+    Eq,
+    NotEq,
+    Lt,
+    LtE,
+    Gt,
+    GtE,
+    Is,
+    IsNot,
+    In,
+    NotIn,
+}
+
+impl From<&Cmpop> for ComparableCmpop {
+    fn from(op: &Cmpop) -> Self {
+        match op {
+            Cmpop::Eq => Self::Eq,
+            Cmpop::NotEq => Self::NotEq,
+            Cmpop::Lt => Self::Lt,
+            Cmpop::LtE => Self::LtE,
+            Cmpop::Gt => Self::Gt,
+            Cmpop::GtE => Self::GtE,
+            Cmpop::Is => Self::Is,
+            Cmpop::IsNot => Self::IsNot,
+            Cmpop::In => Self::In,
+            Cmpop::NotIn => Self::NotIn,
+        }
+    }
+}
+
+#[derive(Debug, PartialEq, Eq, Hash)]
+pub enum ComparableConstant<'a> {
+    None,
+    Bool(&'a bool),
+    Str(&'a str),
+    Bytes(&'a [u8]),
+    Int(&'a BigInt),
+    Tuple(Vec<ComparableConstant<'a>>),
+    Float(u64),
+    Complex { real: u64, imag: u64 },
+    Ellipsis,
+}
+
+impl<'a> From<&'a Constant> for ComparableConstant<'a> {
+    fn from(constant: &'a Constant) -> Self {
+        match constant {
+            Constant::None => Self::None,
+            Constant::Bool(value) => Self::Bool(value),
+            Constant::Str(value) => Self::Str(value),
+            Constant::Bytes(value) => Self::Bytes(value),
+            Constant::Int(value) => Self::Int(value),
+            Constant::Tuple(value) => {
+                Self::Tuple(value.iter().map(std::convert::Into::into).collect())
+            }
+            Constant::Float(value) => Self::Float(value.to_bits()),
+            Constant::Complex { real, imag } => Self::Complex {
+                real: real.to_bits(),
+                imag: imag.to_bits(),
+            },
+            Constant::Ellipsis => Self::Ellipsis,
+        }
+    }
+}
+
+#[derive(Debug, PartialEq, Eq, Hash)]
+pub struct ComparableArguments<'a> {
+    pub posonlyargs: Vec<ComparableArg<'a>>,
+    pub args: Vec<ComparableArg<'a>>,
+    pub vararg: Option<ComparableArg<'a>>,
+    pub kwonlyargs: Vec<ComparableArg<'a>>,
+    pub kw_defaults: Vec<ComparableExpr<'a>>,
+    pub kwarg: Option<ComparableArg<'a>>,
+    pub defaults: Vec<ComparableExpr<'a>>,
+}
+
+impl<'a> From<&'a Arguments> for ComparableArguments<'a> {
+    fn from(arguments: &'a Arguments) -> Self {
+        Self {
+            posonlyargs: arguments
+                .posonlyargs
+                .iter()
+                .map(std::convert::Into::into)
+                .collect(),
+            args: arguments
+                .args
+                .iter()
+                .map(std::convert::Into::into)
+                .collect(),
+            vararg: arguments.vararg.as_ref().map(std::convert::Into::into),
+            kwonlyargs: arguments
+                .kwonlyargs
+                .iter()
+                .map(std::convert::Into::into)
+                .collect(),
+            kw_defaults: arguments
+                .kw_defaults
+                .iter()
+                .map(std::convert::Into::into)
+                .collect(),
+            kwarg: arguments.vararg.as_ref().map(std::convert::Into::into),
+            defaults: arguments
+                .defaults
+                .iter()
+                .map(std::convert::Into::into)
+                .collect(),
+        }
+    }
+}
+
+impl<'a> From<&'a Box<Arg>> for ComparableArg<'a> {
+    fn from(arg: &'a Box<Arg>) -> Self {
+        (&**arg).into()
+    }
+}
+
+#[derive(Debug, PartialEq, Eq, Hash)]
+pub struct ComparableArg<'a> {
+    pub arg: &'a str,
+    pub annotation: Option<Box<ComparableExpr<'a>>>,
+    pub type_comment: Option<&'a str>,
+}
+
+impl<'a> From<&'a Arg> for ComparableArg<'a> {
+    fn from(arg: &'a Arg) -> Self {
+        Self {
+            arg: &arg.node.arg,
+            annotation: arg.node.annotation.as_ref().map(std::convert::Into::into),
+            type_comment: arg.node.type_comment.as_deref(),
+        }
+    }
+}
+
+#[derive(Debug, PartialEq, Eq, Hash)]
+pub struct ComparableKeyword<'a> {
+    pub arg: Option<&'a str>,
+    pub value: ComparableExpr<'a>,
+}
+
+impl<'a> From<&'a Keyword> for ComparableKeyword<'a> {
+    fn from(keyword: &'a Keyword) -> Self {
+        Self {
+            arg: keyword.node.arg.as_deref(),
+            value: (&keyword.node.value).into(),
+        }
+    }
+}
+
+#[derive(Debug, PartialEq, Eq, Hash)]
+pub struct ComparableComprehension<'a> {
+    pub target: ComparableExpr<'a>,
+    pub iter: ComparableExpr<'a>,
+    pub ifs: Vec<ComparableExpr<'a>>,
+    pub is_async: &'a usize,
+}
+
+impl<'a> From<&'a Comprehension> for ComparableComprehension<'a> {
+    fn from(comprehension: &'a Comprehension) -> Self {
+        Self {
+            target: (&comprehension.target).into(),
+            iter: (&comprehension.iter).into(),
+            ifs: comprehension
+                .ifs
+                .iter()
+                .map(std::convert::Into::into)
+                .collect(),
+            is_async: &comprehension.is_async,
+        }
+    }
+}
+
+#[derive(Debug, PartialEq, Eq, Hash)]
+pub enum ComparableExpr<'a> {
+    BoolOp {
+        op: ComparableBoolop,
+        values: Vec<ComparableExpr<'a>>,
+    },
+    NamedExpr {
+        target: Box<ComparableExpr<'a>>,
+        value: Box<ComparableExpr<'a>>,
+    },
+    BinOp {
+        left: Box<ComparableExpr<'a>>,
+        op: ComparableOperator,
+        right: Box<ComparableExpr<'a>>,
+    },
+    UnaryOp {
+        op: ComparableUnaryop,
+        operand: Box<ComparableExpr<'a>>,
+    },
+    Lambda {
+        args: ComparableArguments<'a>,
+        body: Box<ComparableExpr<'a>>,
+    },
+    IfExp {
+        test: Box<ComparableExpr<'a>>,
+        body: Box<ComparableExpr<'a>>,
+        orelse: Box<ComparableExpr<'a>>,
+    },
+    Dict {
+        keys: Vec<ComparableExpr<'a>>,
+        values: Vec<ComparableExpr<'a>>,
+    },
+    Set {
+        elts: Vec<ComparableExpr<'a>>,
+    },
+    ListComp {
+        elt: Box<ComparableExpr<'a>>,
+        generators: Vec<ComparableComprehension<'a>>,
+    },
+    SetComp {
+        elt: Box<ComparableExpr<'a>>,
+        generators: Vec<ComparableComprehension<'a>>,
+    },
+    DictComp {
+        key: Box<ComparableExpr<'a>>,
+        value: Box<ComparableExpr<'a>>,
+        generators: Vec<ComparableComprehension<'a>>,
+    },
+    GeneratorExp {
+        elt: Box<ComparableExpr<'a>>,
+        generators: Vec<ComparableComprehension<'a>>,
+    },
+    Await {
+        value: Box<ComparableExpr<'a>>,
+    },
+    Yield {
+        value: Option<Box<ComparableExpr<'a>>>,
+    },
+    YieldFrom {
+        value: Box<ComparableExpr<'a>>,
+    },
+    Compare {
+        left: Box<ComparableExpr<'a>>,
+        ops: Vec<ComparableCmpop>,
+        comparators: Vec<ComparableExpr<'a>>,
+    },
+    Call {
+        func: Box<ComparableExpr<'a>>,
+        args: Vec<ComparableExpr<'a>>,
+        keywords: Vec<ComparableKeyword<'a>>,
+    },
+    FormattedValue {
+        value: Box<ComparableExpr<'a>>,
+        conversion: &'a usize,
+        format_spec: Option<Box<ComparableExpr<'a>>>,
+    },
+    JoinedStr {
+        values: Vec<ComparableExpr<'a>>,
+    },
+    Constant {
+        value: ComparableConstant<'a>,
+        kind: Option<&'a str>,
+    },
+    Attribute {
+        value: Box<ComparableExpr<'a>>,
+        attr: &'a str,
+        ctx: ComparableExprContext,
+    },
+    Subscript {
+        value: Box<ComparableExpr<'a>>,
+        slice: Box<ComparableExpr<'a>>,
+        ctx: ComparableExprContext,
+    },
+    Starred {
+        value: Box<ComparableExpr<'a>>,
+        ctx: ComparableExprContext,
+    },
+    Name {
+        id: &'a str,
+        ctx: ComparableExprContext,
+    },
+    List {
+        elts: Vec<ComparableExpr<'a>>,
+        ctx: ComparableExprContext,
+    },
+    Tuple {
+        elts: Vec<ComparableExpr<'a>>,
+        ctx: ComparableExprContext,
+    },
+    Slice {
+        lower: Option<Box<ComparableExpr<'a>>>,
+        upper: Option<Box<ComparableExpr<'a>>>,
+        step: Option<Box<ComparableExpr<'a>>>,
+    },
+}
+
+impl<'a> From<&'a Box<Expr>> for Box<ComparableExpr<'a>> {
+    fn from(expr: &'a Box<Expr>) -> Self {
+        Box::new((&**expr).into())
+    }
+}
+
+impl<'a> From<&'a Box<Expr>> for ComparableExpr<'a> {
+    fn from(expr: &'a Box<Expr>) -> Self {
+        (&**expr).into()
+    }
+}
+
+impl<'a> From<&'a Expr> for ComparableExpr<'a> {
+    fn from(expr: &'a Expr) -> Self {
+        match &expr.node {
+            ExprKind::BoolOp { op, values } => Self::BoolOp {
+                op: op.into(),
+                values: values.iter().map(std::convert::Into::into).collect(),
+            },
+            ExprKind::NamedExpr { target, value } => Self::NamedExpr {
+                target: target.into(),
+                value: value.into(),
+            },
+            ExprKind::BinOp { left, op, right } => Self::BinOp {
+                left: left.into(),
+                op: op.into(),
+                right: right.into(),
+            },
+            ExprKind::UnaryOp { op, operand } => Self::UnaryOp {
+                op: op.into(),
+                operand: operand.into(),
+            },
+            ExprKind::Lambda { args, body } => Self::Lambda {
+                args: (&**args).into(),
+                body: body.into(),
+            },
+            ExprKind::IfExp { test, body, orelse } => Self::IfExp {
+                test: test.into(),
+                body: body.into(),
+                orelse: orelse.into(),
+            },
+            ExprKind::Dict { keys, values } => Self::Dict {
+                keys: keys.iter().map(std::convert::Into::into).collect(),
+                values: values.iter().map(std::convert::Into::into).collect(),
+            },
+            ExprKind::Set { elts } => Self::Set {
+                elts: elts.iter().map(std::convert::Into::into).collect(),
+            },
+            ExprKind::ListComp { elt, generators } => Self::ListComp {
+                elt: elt.into(),
+                generators: generators.iter().map(std::convert::Into::into).collect(),
+            },
+            ExprKind::SetComp { elt, generators } => Self::SetComp {
+                elt: elt.into(),
+                generators: generators.iter().map(std::convert::Into::into).collect(),
+            },
+            ExprKind::DictComp {
+                key,
+                value,
+                generators,
+            } => Self::DictComp {
+                key: key.into(),
+                value: value.into(),
+                generators: generators.iter().map(std::convert::Into::into).collect(),
+            },
+            ExprKind::GeneratorExp { elt, generators } => Self::GeneratorExp {
+                elt: elt.into(),
+                generators: generators.iter().map(std::convert::Into::into).collect(),
+            },
+            ExprKind::Await { value } => Self::Await {
+                value: value.into(),
+            },
+            ExprKind::Yield { value } => Self::Yield {
+                value: value.as_ref().map(std::convert::Into::into),
+            },
+            ExprKind::YieldFrom { value } => Self::YieldFrom {
+                value: value.into(),
+            },
+            ExprKind::Compare {
+                left,
+                ops,
+                comparators,
+            } => Self::Compare {
+                left: left.into(),
+                ops: ops.iter().map(std::convert::Into::into).collect(),
+                comparators: comparators.iter().map(std::convert::Into::into).collect(),
+            },
+            ExprKind::Call {
+                func,
+                args,
+                keywords,
+            } => Self::Call {
+                func: func.into(),
+                args: args.iter().map(std::convert::Into::into).collect(),
+                keywords: keywords.iter().map(std::convert::Into::into).collect(),
+            },
+            ExprKind::FormattedValue {
+                value,
+                conversion,
+                format_spec,
+            } => Self::FormattedValue {
+                value: value.into(),
+                conversion,
+                format_spec: format_spec.as_ref().map(std::convert::Into::into),
+            },
+            ExprKind::JoinedStr { values } => Self::JoinedStr {
+                values: values.iter().map(std::convert::Into::into).collect(),
+            },
+            ExprKind::Constant { value, kind } => Self::Constant {
+                value: value.into(),
+                kind: kind.as_ref().map(String::as_str),
+            },
+            ExprKind::Attribute { value, attr, ctx } => Self::Attribute {
+                value: value.into(),
+                attr,
+                ctx: ctx.into(),
+            },
+            ExprKind::Subscript { value, slice, ctx } => Self::Subscript {
+                value: value.into(),
+                slice: slice.into(),
+                ctx: ctx.into(),
+            },
+            ExprKind::Starred { value, ctx } => Self::Starred {
+                value: value.into(),
+                ctx: ctx.into(),
+            },
+            ExprKind::Name { id, ctx } => Self::Name {
+                id,
+                ctx: ctx.into(),
+            },
+            ExprKind::List { elts, ctx } => Self::List {
+                elts: elts.iter().map(std::convert::Into::into).collect(),
+                ctx: ctx.into(),
+            },
+            ExprKind::Tuple { elts, ctx } => Self::Tuple {
+                elts: elts.iter().map(std::convert::Into::into).collect(),
+                ctx: ctx.into(),
+            },
+            ExprKind::Slice { lower, upper, step } => Self::Slice {
+                lower: lower.as_ref().map(std::convert::Into::into),
+                upper: upper.as_ref().map(std::convert::Into::into),
+                step: step.as_ref().map(std::convert::Into::into),
+            },
+        }
+    }
+}
--- a/src/ast/helpers.rs
+++ b/src/ast/helpers.rs
@@ -11,7 +11,9 @@ use rustpython_parser::lexer;
 use rustpython_parser::lexer::Tok;
 use rustpython_parser::token::StringKind;

-use crate::ast::types::Range;
+use crate::ast::types::{Binding, BindingKind, Range};
+use crate::source_code_generator::SourceCodeGenerator;
+use crate::source_code_style::SourceCodeStyleDetector;
 use crate::SourceCodeLocator;

 /// Create an `Expr` with default location from an `ExprKind`.
@@ -24,6 +26,20 @@ pub fn create_stmt(node: StmtKind) -> Stmt {
    Stmt::new(Location::default(), Location::default(), node)
 }

+/// Generate source code from an `Expr`.
+pub fn unparse_expr(expr: &Expr, stylist: &SourceCodeStyleDetector) -> String {
+    let mut generator: SourceCodeGenerator = stylist.into();
+    generator.unparse_expr(expr, 0);
+    generator.generate()
+}
+
+/// Generate source code from an `Stmt`.
+pub fn unparse_stmt(stmt: &Stmt, stylist: &SourceCodeStyleDetector) -> String {
+    let mut generator: SourceCodeGenerator = stylist.into();
+    generator.unparse_stmt(stmt);
+    generator.generate()
+}
+
 fn collect_call_path_inner<'a>(expr: &'a Expr, parts: &mut Vec<&'a str>) {
    match &expr.node {
        ExprKind::Call { func, .. } => {
@@ -163,6 +179,131 @@ pub fn match_call_path(
    }
 }

+/// Return `true` if the `Expr` contains a reference to `${module}.${target}`.
+pub fn contains_call_path(
+    expr: &Expr,
+    module: &str,
+    member: &str,
+    import_aliases: &FxHashMap<&str, &str>,
+    from_imports: &FxHashMap<&str, FxHashSet<&str>>,
+) -> bool {
+    any_over_expr(expr, &|expr| {
+        let call_path = collect_call_paths(expr);
+        if !call_path.is_empty() {
+            if match_call_path(
+                &dealias_call_path(call_path, import_aliases),
+                module,
+                member,
+                from_imports,
+            ) {
+                return true;
+            }
+        }
+        false
+    })
+}
+
+/// Call `func` over every `Expr` in `expr`, returning `true` if any expression
+/// returns `true`..
+pub fn any_over_expr<F>(expr: &Expr, func: &F) -> bool
+where
+    F: Fn(&Expr) -> bool,
+{
+    if func(expr) {
+        return true;
+    }
+    match &expr.node {
+        ExprKind::BoolOp { values, .. } | ExprKind::JoinedStr { values } => {
+            values.iter().any(|expr| any_over_expr(expr, func))
+        }
+        ExprKind::NamedExpr { target, value } => {
+            any_over_expr(target, func) || any_over_expr(value, func)
+        }
+        ExprKind::BinOp { left, right, .. } => {
+            any_over_expr(left, func) || any_over_expr(right, func)
+        }
+        ExprKind::UnaryOp { operand, .. } => any_over_expr(operand, func),
+        ExprKind::Lambda { body, .. } => any_over_expr(body, func),
+        ExprKind::IfExp { test, body, orelse } => {
+            any_over_expr(test, func) || any_over_expr(body, func) || any_over_expr(orelse, func)
+        }
+        ExprKind::Dict { keys, values } => values
+            .iter()
+            .chain(keys.iter())
+            .any(|expr| any_over_expr(expr, func)),
+        ExprKind::Set { elts } | ExprKind::List { elts, .. } | ExprKind::Tuple { elts, .. } => {
+            elts.iter().any(|expr| any_over_expr(expr, func))
+        }
+        ExprKind::ListComp { elt, generators }
+        | ExprKind::SetComp { elt, generators }
+        | ExprKind::GeneratorExp { elt, generators } => {
+            any_over_expr(elt, func)
+                || generators.iter().any(|generator| {
+                    any_over_expr(&generator.target, func)
+                        || any_over_expr(&generator.iter, func)
+                        || generator.ifs.iter().any(|expr| any_over_expr(expr, func))
+                })
+        }
+        ExprKind::DictComp {
+            key,
+            value,
+            generators,
+        } => {
+            any_over_expr(key, func)
+                || any_over_expr(value, func)
+                || generators.iter().any(|generator| {
+                    any_over_expr(&generator.target, func)
+                        || any_over_expr(&generator.iter, func)
+                        || generator.ifs.iter().any(|expr| any_over_expr(expr, func))
+                })
+        }
+        ExprKind::Await { value }
+        | ExprKind::YieldFrom { value }
+        | ExprKind::Attribute { value, .. }
+        | ExprKind::Starred { value, .. } => any_over_expr(value, func),
+        ExprKind::Yield { value } => value
+            .as_ref()
+            .map_or(false, |value| any_over_expr(value, func)),
+        ExprKind::Compare {
+            left, comparators, ..
+        } => any_over_expr(left, func) || comparators.iter().any(|expr| any_over_expr(expr, func)),
+        ExprKind::Call {
+            func: call_func,
+            args,
+            keywords,
+        } => {
+            any_over_expr(call_func, func)
+                || args.iter().any(|expr| any_over_expr(expr, func))
+                || keywords
+                    .iter()
+                    .any(|keyword| any_over_expr(&keyword.node.value, func))
+        }
+        ExprKind::FormattedValue {
+            value, format_spec, ..
+        } => {
+            any_over_expr(value, func)
+                || format_spec
+                    .as_ref()
+                    .map_or(false, |value| any_over_expr(value, func))
+        }
+        ExprKind::Subscript { value, slice, .. } => {
+            any_over_expr(value, func) || any_over_expr(slice, func)
+        }
+        ExprKind::Slice { lower, upper, step } => {
+            lower
+                .as_ref()
+                .map_or(false, |value| any_over_expr(value, func))
+                || upper
+                    .as_ref()
+                    .map_or(false, |value| any_over_expr(value, func))
+                || step
+                    .as_ref()
+                    .map_or(false, |value| any_over_expr(value, func))
+        }
+        ExprKind::Name { .. } | ExprKind::Constant { .. } => false,
+    }
+}
+
 static DUNDER_REGEX: Lazy<Regex> = Lazy::new(|| Regex::new(r"__[^\s]+__").unwrap());

 /// Return `true` if the `Stmt` is an assignment to a dunder (like `__all__`).
@@ -175,12 +316,12 @@ pub fn is_assignment_to_a_dunder(stmt: &Stmt) -> bool {
                return false;
            }
            match &targets[0].node {
-                ExprKind::Name { id, ctx: _ } => DUNDER_REGEX.is_match(id),
+                ExprKind::Name { id, .. } => DUNDER_REGEX.is_match(id),
                _ => false,
            }
        }
        StmtKind::AnnAssign { target, .. } => match &target.node {
-            ExprKind::Name { id, ctx: _ } => DUNDER_REGEX.is_match(id),
+            ExprKind::Name { id, .. } => DUNDER_REGEX.is_match(id),
            _ => false,
        },
        _ => false,
@@ -213,23 +354,6 @@ pub fn is_constant_non_singleton(expr: &Expr) -> bool {
    is_constant(expr) && !is_singleton(expr)
 }

-/// Return `true` if an `Expr` is not a reference to a variable (or something
-/// that could resolve to a variable, like a function call).
-pub fn is_non_variable(expr: &Expr) -> bool {
-    matches!(
-        expr.node,
-        ExprKind::Constant { .. }
-            | ExprKind::Tuple { .. }
-            | ExprKind::List { .. }
-            | ExprKind::Set { .. }
-            | ExprKind::Dict { .. }
-            | ExprKind::SetComp { .. }
-            | ExprKind::ListComp { .. }
-            | ExprKind::DictComp { .. }
-            | ExprKind::GeneratorExp { .. }
-    )
-}
-
 /// Return the `Keyword` with the given name, if it's present in the list of
 /// `Keyword` arguments.
 pub fn find_keyword<'a>(keywords: &'a [Keyword], keyword_name: &str) -> Option<&'a Keyword> {
@@ -306,6 +430,13 @@ pub fn collect_arg_names<'a>(arguments: &'a Arguments) -> FxHashSet<&'a str> {
    arg_names
 }

+/// Returns `true` if a statement or expression includes at least one comment.
+pub fn has_comments<T>(located: &Located<T>, locator: &SourceCodeLocator) -> bool {
+    lexer::make_tokenizer(&locator.slice_source_code_range(&Range::from_located(located)))
+        .flatten()
+        .any(|(_, tok, _)| matches!(tok, Tok::Comment(..)))
+}
+
 /// Returns `true` if a call is an argumented `super` invocation.
 pub fn is_super_call_with_arguments(func: &Expr, args: &[Expr]) -> bool {
    if let ExprKind::Name { id, .. } = &func.node {
@@ -316,7 +447,7 @@ pub fn is_super_call_with_arguments(func: &Expr, args: &[Expr]) -> bool {
 }

 /// Format the module name for a relative import.
-pub fn format_import_from(level: Option<&usize>, module: Option<&String>) -> String {
+pub fn format_import_from(level: Option<&usize>, module: Option<&str>) -> String {
    let mut module_name = String::with_capacity(16);
    if let Some(level) = level {
        for _ in 0..*level {
@@ -407,6 +538,22 @@ pub fn identifier_range(stmt: &Stmt, locator: &SourceCodeLocator) -> Range {
    Range::from_located(stmt)
 }

+/// Like `identifier_range`, but accepts a `Binding`.
+pub fn binding_range(binding: &Binding, locator: &SourceCodeLocator) -> Range {
+    if matches!(
+        binding.kind,
+        BindingKind::ClassDefinition | BindingKind::FunctionDefinition
+    ) {
+        if let Some(source) = &binding.source {
+            identifier_range(source, locator)
+        } else {
+            binding.range
+        }
+    } else {
+        binding.range
+    }
+}
+
 // Return the ranges of `Name` tokens within a specified node.
 pub fn find_names<T>(located: &Located<T>, locator: &SourceCodeLocator) -> Vec<Range> {
    let contents = locator.slice_source_code_range(&Range::from_located(located));
@@ -555,7 +702,7 @@ pub fn preceded_by_continuation(stmt: &Stmt, locator: &SourceCodeLocator) -> boo
            Location::new(stmt.location.row(), 0),
        );
        let line = locator.slice_source_code_range(&range);
-        if line.trim().ends_with('\\') {
+        if line.trim_end().ends_with('\\') {
            return true;
        }
    }
@@ -574,6 +721,21 @@ pub fn followed_by_multi_statement_line(stmt: &Stmt, locator: &SourceCodeLocator
    match_trailing_content(stmt, locator)
 }

+/// Return `true` if a `Stmt` is a docstring.
+pub fn is_docstring_stmt(stmt: &Stmt) -> bool {
+    if let StmtKind::Expr { value } = &stmt.node {
+        matches!(
+            value.node,
+            ExprKind::Constant {
+                value: Constant::Str { .. },
+                ..
+            }
+        )
+    } else {
+        false
+    }
+}
+
 #[derive(Default)]
 /// A simple representation of a call's positional and keyword arguments.
 pub struct SimpleCallArgs<'a> {
@@ -582,7 +744,7 @@ pub struct SimpleCallArgs<'a> {
 }

 impl<'a> SimpleCallArgs<'a> {
-    pub fn new(args: &'a Vec<Expr>, keywords: &'a Vec<Keyword>) -> Self {
+    pub fn new(args: &'a [Expr], keywords: &'a [Keyword]) -> Self {
        let mut result = SimpleCallArgs::default();

        for arg in args {
@@ -619,6 +781,11 @@ impl<'a> SimpleCallArgs<'a> {
        }
        None
    }
+
+    /// Get the number of positional and keyword arguments used.
+    pub fn len(&self) -> usize {
+        self.args.len() + self.kwargs.len()
+    }
 }

 #[cfg(test)]
--- a/src/ast/mod.rs
+++ b/src/ast/mod.rs
@@ -1,5 +1,6 @@
 pub mod branch_detection;
 pub mod cast;
+pub mod comparable;
 pub mod function_type;
 pub mod helpers;
 pub mod operations;
--- a/src/ast/operations.rs
+++ b/src/ast/operations.rs
@@ -4,6 +4,7 @@ use rustpython_parser::ast::{Constant, Expr, ExprKind, Stmt, StmtKind};
 use rustpython_parser::lexer;
 use rustpython_parser::lexer::Tok;

+use crate::ast::helpers::any_over_expr;
 use crate::ast::types::{Binding, BindingKind, Scope};
 use crate::ast::visitor;
 use crate::ast::visitor::Visitor;
@@ -120,7 +121,7 @@ pub fn on_conditional_branch<'a>(parents: &mut impl Iterator<Item = &'a Stmt>) -
 }

 /// Check if a node is in a nested block.
-pub fn in_nested_block<'a>(parents: &mut impl Iterator<Item = &'a Stmt>) -> bool {
+pub fn in_nested_block<'a>(mut parents: impl Iterator<Item = &'a Stmt>) -> bool {
    parents.any(|parent| {
        matches!(
            parent.node,
@@ -129,76 +130,13 @@ pub fn in_nested_block<'a>(parents: &mut impl Iterator<Item = &'a Stmt>) -> bool
    })
 }

-/// Returns `true` if `parent` contains `child`.
-fn contains(parent: &Expr, child: &Expr) -> bool {
-    match &parent.node {
-        ExprKind::BoolOp { values, .. } => values.iter().any(|parent| contains(parent, child)),
-        ExprKind::NamedExpr { target, value } => contains(target, child) || contains(value, child),
-        ExprKind::BinOp { left, right, .. } => contains(left, child) || contains(right, child),
-        ExprKind::UnaryOp { operand, .. } => contains(operand, child),
-        ExprKind::Lambda { body, .. } => contains(body, child),
-        ExprKind::IfExp { test, body, orelse } => {
-            contains(test, child) || contains(body, child) || contains(orelse, child)
-        }
-        ExprKind::Dict { keys, values } => keys
-            .iter()
-            .chain(values.iter())
-            .any(|parent| contains(parent, child)),
-        ExprKind::Set { elts } => elts.iter().any(|parent| contains(parent, child)),
-        ExprKind::ListComp { elt, .. } => contains(elt, child),
-        ExprKind::SetComp { elt, .. } => contains(elt, child),
-        ExprKind::DictComp { key, value, .. } => contains(key, child) || contains(value, child),
-        ExprKind::GeneratorExp { elt, .. } => contains(elt, child),
-        ExprKind::Await { value } => contains(value, child),
-        ExprKind::Yield { value } => value.as_ref().map_or(false, |value| contains(value, child)),
-        ExprKind::YieldFrom { value } => contains(value, child),
-        ExprKind::Compare {
-            left, comparators, ..
-        } => contains(left, child) || comparators.iter().any(|parent| contains(parent, child)),
-        ExprKind::Call {
-            func,
-            args,
-            keywords,
-        } => {
-            contains(func, child)
-                || args.iter().any(|parent| contains(parent, child))
-                || keywords
-                    .iter()
-                    .any(|keyword| contains(&keyword.node.value, child))
-        }
-        ExprKind::FormattedValue {
-            value, format_spec, ..
-        } => {
-            contains(value, child)
-                || format_spec
-                    .as_ref()
-                    .map_or(false, |value| contains(value, child))
-        }
-        ExprKind::JoinedStr { values } => values.iter().any(|parent| contains(parent, child)),
-        ExprKind::Constant { .. } => false,
-        ExprKind::Attribute { value, .. } => contains(value, child),
-        ExprKind::Subscript { value, slice, .. } => {
-            contains(value, child) || contains(slice, child)
-        }
-        ExprKind::Starred { value, .. } => contains(value, child),
-        ExprKind::Name { .. } => parent == child,
-        ExprKind::List { elts, .. } => elts.iter().any(|parent| contains(parent, child)),
-        ExprKind::Tuple { elts, .. } => elts.iter().any(|parent| contains(parent, child)),
-        ExprKind::Slice { lower, upper, step } => {
-            lower.as_ref().map_or(false, |value| contains(value, child))
-                || upper.as_ref().map_or(false, |value| contains(value, child))
-                || step.as_ref().map_or(false, |value| contains(value, child))
-        }
-    }
-}
-
 /// Check if a node represents an unpacking assignment.
 pub fn is_unpacking_assignment(parent: &Stmt, child: &Expr) -> bool {
    match &parent.node {
        StmtKind::With { items, .. } => items.iter().any(|item| {
            if let Some(optional_vars) = &item.optional_vars {
                if matches!(optional_vars.node, ExprKind::Tuple { .. }) {
-                    if contains(optional_vars, child) {
+                    if any_over_expr(optional_vars, &|expr| expr == child) {
                        return true;
                    }
                }
@@ -212,7 +150,7 @@ pub fn is_unpacking_assignment(parent: &Stmt, child: &Expr) -> bool {
                ExprKind::Set { .. } | ExprKind::List { .. } | ExprKind::Tuple { .. }
            );
            // In `(a, b) = coords = (1, 2)`, `(a, b)` and `coords` are the targets, and
-            // `(a, b`) is a tuple. (We use "tuple" as a placeholder for any
+            // `(a, b)` is a tuple. (We use "tuple" as a placeholder for any
            // unpackable expression.)
            let targets_are_tuples = targets.iter().all(|item| {
                matches!(
@@ -227,7 +165,7 @@ pub fn is_unpacking_assignment(parent: &Stmt, child: &Expr) -> bool {
                    matches!(
                        item.node,
                        ExprKind::Set { .. } | ExprKind::List { .. } | ExprKind::Tuple { .. }
-                    ) && contains(item, child)
+                    ) && any_over_expr(item, &|expr| expr == child)
                });

            // If our child is a tuple, and value is not, it's always an unpacking
--- a/src/ast/types.rs
+++ b/src/ast/types.rs
@@ -1,3 +1,4 @@
+use std::ops::Deref;
 use std::sync::atomic::{AtomicUsize, Ordering};

 use rustc_hash::FxHashMap;
@@ -215,3 +216,23 @@ impl<'a, 'b, T> PartialEq<RefEquality<'b, T>> for RefEquality<'a, T> {
 }

 impl<'a, T> Eq for RefEquality<'a, T> {}
+
+impl<'a, T> Deref for RefEquality<'a, T> {
+    type Target = T;
+
+    fn deref(&self) -> &T {
+        self.0
+    }
+}
+
+impl<'a> From<&RefEquality<'a, Stmt>> for &'a Stmt {
+    fn from(r: &RefEquality<'a, Stmt>) -> Self {
+        r.0
+    }
+}
+
+impl<'a> From<&RefEquality<'a, Expr>> for &'a Expr {
+    fn from(r: &RefEquality<'a, Expr>) -> Self {
+        r.0
+    }
+}
--- a/src/autofix/fixer.rs
+++ b/src/autofix/fixer.rs
@@ -7,7 +7,7 @@ use rustpython_parser::ast::Location;

 use crate::ast::types::Range;
 use crate::autofix::Fix;
-use crate::registry::Check;
+use crate::registry::Diagnostic;
 use crate::source_code_locator::SourceCodeLocator;

 #[derive(Debug, Copy, Clone, Hash)]
@@ -30,15 +30,15 @@ impl From<bool> for Mode {

 /// Auto-fix errors in a file, and write the fixed source code to disk.
 pub fn fix_file<'a>(
-    checks: &'a [Check],
+    diagnostics: &'a [Diagnostic],
    locator: &'a SourceCodeLocator<'a>,
 ) -> Option<(Cow<'a, str>, usize)> {
-    if checks.iter().all(|check| check.fix.is_none()) {
+    if diagnostics.iter().all(|check| check.fix.is_none()) {
        return None;
    }

    Some(apply_fixes(
-        checks.iter().filter_map(|check| check.fix.as_ref()),
+        diagnostics.iter().filter_map(|check| check.fix.as_ref()),
        locator,
    ))
 }
--- a/src/cache.rs
+++ b/src/cache.rs
@@ -1,6 +1,5 @@
 use std::collections::hash_map::DefaultHasher;
 use std::fs;
-use std::fs::{create_dir_all, File, Metadata};
 use std::hash::{Hash, Hasher};
 use std::io::Write;
 use std::path::{Path, PathBuf};
@@ -8,16 +7,15 @@ use std::path::{Path, PathBuf};
 use anyhow::Result;
 use filetime::FileTime;
 use log::error;
-use once_cell::sync::Lazy;
 use path_absolutize::Absolutize;
 use serde::{Deserialize, Serialize};

 use crate::message::Message;
 use crate::settings::{flags, Settings};

+pub const CACHE_DIR_NAME: &str = ".ruff_cache";
+
 const CARGO_PKG_VERSION: &str = env!("CARGO_PKG_VERSION");
-static CACHE_DIR: Lazy<Option<String>> = Lazy::new(|| std::env::var("RUFF_CACHE_DIR").ok());
-pub const DEFAULT_CACHE_DIR_NAME: &str = ".ruff_cache";

 #[derive(Serialize, Deserialize)]
 struct CacheMetadata {
@@ -39,9 +37,7 @@ struct CheckResult {
 /// Return the cache directory for a given project root. Defers to the
 /// `RUFF_CACHE_DIR` environment variable, if set.
 pub fn cache_dir(project_root: &Path) -> PathBuf {
-    CACHE_DIR
-        .as_ref()
-        .map_or_else(|| project_root.join(DEFAULT_CACHE_DIR_NAME), PathBuf::from)
+    project_root.join(CACHE_DIR_NAME)
 }

 fn content_dir() -> &'static Path {
@@ -60,7 +56,7 @@ fn cache_key<P: AsRef<Path>>(path: P, settings: &Settings, autofix: flags::Autof
 /// Initialize the cache at the specified `Path`.
 pub fn init(path: &Path) -> Result<()> {
    // Create the cache directories.
-    create_dir_all(path.join(content_dir()))?;
+    fs::create_dir_all(path.join(content_dir()))?;

    // Add the CACHEDIR.TAG.
    if !cachedir::is_tagged(path)? {
@@ -70,7 +66,7 @@ pub fn init(path: &Path) -> Result<()> {
    // Add the .gitignore.
    let gitignore_path = path.join(".gitignore");
    if !gitignore_path.exists() {
-        let mut file = File::create(gitignore_path)?;
+        let mut file = fs::File::create(gitignore_path)?;
        file.write_all(b"*")?;
    }

@@ -91,7 +87,7 @@ fn read_sync(cache_dir: &Path, key: u64) -> Result<Vec<u8>, std::io::Error> {
 /// Get a value from the cache.
 pub fn get<P: AsRef<Path>>(
    path: P,
-    metadata: &Metadata,
+    metadata: &fs::Metadata,
    settings: &Settings,
    autofix: flags::Autofix,
 ) -> Option<Vec<Message>> {
@@ -115,7 +111,7 @@ pub fn get<P: AsRef<Path>>(
 /// Set a value in the cache.
 pub fn set<P: AsRef<Path>>(
    path: P,
-    metadata: &Metadata,
+    metadata: &fs::Metadata,
    settings: &Settings,
    autofix: flags::Autofix,
    messages: &[Message],
--- a/Show More
+++ b/Show More