Try thin lto

Let's see what impact on performance this has

.github/workflows/ci.yaml

@@ -184,7 +184,11 @@ jobs:
       - cargo-test-linux
       - determine_changes
     # Only runs on pull requests, since that is the only we way we can find the base version for comparison.
-    if: github.event_name == 'pull_request'
+    # Ecosystem check needs linter and/or formatter changes.
+    if: github.event_name == 'pull_request' && ${{
+      needs.determine_changes.outputs.linter == 'true' ||
+      needs.determine_changes.outputs.formatter == 'true'
+      }}
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-python@v4

.pre-commit-config.yaml

@@ -13,12 +13,12 @@ exclude: |
 
 repos:
   - repo: https://github.com/abravalheri/validate-pyproject
-    rev: v0.12.1
+    rev: v0.15
     hooks:
       - id: validate-pyproject
 
   - repo: https://github.com/executablebooks/mdformat
-    rev: 0.7.16
+    rev: 0.7.17
     hooks:
       - id: mdformat
         additional_dependencies:
@@ -26,16 +26,22 @@ repos:
           - mdformat-admon
         exclude: |
           (?x)^(
-            docs/formatter/black.md
+            docs/formatter/black\.md
+            | docs/\w+\.md
           )$
 
   - repo: https://github.com/igorshubovych/markdownlint-cli
-    rev: v0.33.0
+    rev: v0.37.0
     hooks:
       - id: markdownlint-fix
+        exclude: |
+          (?x)^(
+            docs/formatter/black\.md
+            | docs/\w+\.md
+          )$
 
   - repo: https://github.com/crate-ci/typos
-    rev: v1.14.12
+    rev: v1.16.22
     hooks:
       - id: typos
 
@@ -49,7 +55,7 @@ repos:
         pass_filenames: false # This makes it a lot faster
 
   - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.1.3
+    rev: v0.1.4
     hooks:
       - id: ruff-format
       - id: ruff
@@ -64,7 +70,7 @@ repos:
 
   # Prettier
   - repo: https://github.com/pre-commit/mirrors-prettier
-    rev: v3.0.0
+    rev: v3.0.3
     hooks:
       - id: prettier
         types: [yaml]

CODE_OF_CONDUCT.md

@@ -72,7 +72,7 @@ representative at an online or offline event.
 
 Instances of abusive, harassing, or otherwise unacceptable behavior may be
 reported to the community leaders responsible for enforcement at
-charlie.r.marsh@gmail.com.
+<charlie.r.marsh@gmail.com>.
 All complaints will be reviewed and investigated promptly and fairly.
 
 All community leaders are obligated to respect the privacy and security of the

Cargo.lock

@@ -210,9 +210,9 @@ checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
 
 [[package]]
 name = "bitflags"
-version = "2.4.0"
+version = "2.4.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b4682ae6287fcf752ecaabbfcc7b6f9b72aa33933dc23a554d853aea8eea8635"
+checksum = "327762f6e5a765692301e5bb513e0d9fef63be86bbc14528052b1cd3e6f03e07"
 
 [[package]]
 name = "bstr"
@@ -383,7 +383,7 @@ dependencies = [
  "heck",
  "proc-macro2",
  "quote",
- "syn 2.0.38",
+ "syn 2.0.39",
 ]
 
 [[package]]
@@ -407,9 +407,9 @@ dependencies = [
 
 [[package]]
 name = "codspeed"
-version = "2.3.0"
+version = "2.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d680ccd1eedd2dd7c7a3649a78c7d06e0f16b191b30d81cc58e7bc906488d344"
+checksum = "918b13a0f1a32460ab3bd5debd56b5a27a7071fa5ff5dfeb3a5cf291a85b174b"
 dependencies = [
  "colored",
  "libc",
@@ -418,9 +418,9 @@ dependencies = [
 
 [[package]]
 name = "codspeed-criterion-compat"
-version = "2.3.0"
+version = "2.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "58b48b6c8e890d7d4ad0ed85e9ab4949bf7023198c006000ef6338ba84cf5b71"
+checksum = "c683c7fef2b873fbbdf4062782914c652309951244bf0bd362fe608b7d6f901c"
 dependencies = [
  "codspeed",
  "colored",
@@ -608,7 +608,7 @@ dependencies = [
  "proc-macro2",
  "quote",
  "strsim",
- "syn 2.0.38",
+ "syn 2.0.39",
 ]
 
 [[package]]
@@ -619,7 +619,7 @@ checksum = "836a9bbc7ad63342d6d6e7b815ccab164bc77a2d95d84bc3117a8c0d5c98e2d5"
 dependencies = [
  "darling_core",
  "quote",
- "syn 2.0.38",
+ "syn 2.0.39",
 ]
 
 [[package]]
@@ -1129,7 +1129,7 @@ dependencies = [
  "pmutil 0.6.1",
  "proc-macro2",
  "quote",
- "syn 2.0.38",
+ "syn 2.0.39",
 ]
 
 [[package]]
@@ -1440,7 +1440,7 @@ version = "6.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6205bd8bb1e454ad2e27422015fb5e4f2bcc7e08fa8f27058670d208324a4d2d"
 dependencies = [
- "bitflags 2.4.0",
+ "bitflags 2.4.1",
  "crossbeam-channel",
  "filetime",
  "fsevent-sys",
@@ -1707,7 +1707,7 @@ checksum = "52a40bc70c2c58040d2d8b167ba9a5ff59fc9dab7ad44771cfde3dcfde7a09c6"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.38",
+ "syn 2.0.39",
 ]
 
 [[package]]
@@ -2067,7 +2067,7 @@ dependencies = [
  "argfile",
  "assert_cmd",
  "bincode",
- "bitflags 2.4.0",
+ "bitflags 2.4.1",
  "cachedir",
  "chrono",
  "clap",
@@ -2201,7 +2201,7 @@ dependencies = [
  "aho-corasick",
  "annotate-snippets 0.9.1",
  "anyhow",
- "bitflags 2.4.0",
+ "bitflags 2.4.1",
  "chrono",
  "clap",
  "colored",
@@ -2267,7 +2267,7 @@ dependencies = [
  "proc-macro2",
  "quote",
  "ruff_python_trivia",
- "syn 2.0.38",
+ "syn 2.0.39",
 ]
 
 [[package]]
@@ -2293,7 +2293,7 @@ dependencies = [
 name = "ruff_python_ast"
 version = "0.0.0"
 dependencies = [
- "bitflags 2.4.0",
+ "bitflags 2.4.1",
  "insta",
  "is-macro",
  "itertools 0.11.0",
@@ -2325,7 +2325,7 @@ name = "ruff_python_formatter"
 version = "0.0.0"
 dependencies = [
  "anyhow",
- "bitflags 2.4.0",
+ "bitflags 2.4.1",
  "clap",
  "countme",
  "insta",
@@ -2369,7 +2369,7 @@ dependencies = [
 name = "ruff_python_literal"
 version = "0.0.0"
 dependencies = [
- "bitflags 2.4.0",
+ "bitflags 2.4.1",
  "hexf-parse",
  "is-macro",
  "itertools 0.11.0",
@@ -2383,7 +2383,7 @@ name = "ruff_python_parser"
 version = "0.0.0"
 dependencies = [
  "anyhow",
- "bitflags 2.4.0",
+ "bitflags 2.4.1",
  "insta",
  "is-macro",
  "itertools 0.11.0",
@@ -2413,7 +2413,7 @@ dependencies = [
 name = "ruff_python_semantic"
 version = "0.0.0"
 dependencies = [
- "bitflags 2.4.0",
+ "bitflags 2.4.1",
  "is-macro",
  "ruff_index",
  "ruff_python_ast",
@@ -2563,7 +2563,7 @@ version = "0.38.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2b426b0506e5d50a7d8dafcf2e81471400deb602392c7dd110815afb4eaf02a3"
 dependencies = [
- "bitflags 2.4.0",
+ "bitflags 2.4.1",
  "errno",
  "libc",
  "linux-raw-sys",
@@ -2682,9 +2682,9 @@ dependencies = [
 
 [[package]]
 name = "serde-wasm-bindgen"
-version = "0.6.0"
+version = "0.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "30c9933e5689bd420dc6c87b7a1835701810cbc10cd86a26e4da45b73e6b1d78"
+checksum = "17ba92964781421b6cef36bf0d7da26d201e96d84e1b10e7ae6ed416e516906d"
 dependencies = [
  "js-sys",
  "serde",
@@ -2699,7 +2699,7 @@ checksum = "67c5609f394e5c2bd7fc51efda478004ea80ef42fee983d5c67a65e34f32c0e3"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.38",
+ "syn 2.0.39",
 ]
 
 [[package]]
@@ -2715,9 +2715,9 @@ dependencies = [
 
 [[package]]
 name = "serde_json"
-version = "1.0.107"
+version = "1.0.108"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6b420ce6e3d8bd882e9b243c6eed35dbc9a6110c9769e74b584e0d68d1f20c65"
+checksum = "3d1c7e3eac408d115102c4c24ad393e0821bb3a5df4d506a80f85f7a742a526b"
 dependencies = [
  "itoa",
  "ryu",
@@ -2761,7 +2761,7 @@ dependencies = [
  "darling",
  "proc-macro2",
  "quote",
- "syn 2.0.38",
+ "syn 2.0.39",
 ]
 
 [[package]]
@@ -2856,7 +2856,7 @@ dependencies = [
  "proc-macro2",
  "quote",
  "rustversion",
- "syn 2.0.38",
+ "syn 2.0.39",
 ]
 
 [[package]]
@@ -2872,9 +2872,9 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "2.0.38"
+version = "2.0.39"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e96b79aaa137db8f61e26363a0c9b47d8b4ec75da28b7d1d614c2303e232408b"
+checksum = "23e78b90f2fcf45d3e842032ce32e3f2d1545ba6636271dcbf24fa306d87be7a"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -2961,7 +2961,7 @@ dependencies = [
  "proc-macro-error",
  "proc-macro2",
  "quote",
- "syn 2.0.38",
+ "syn 2.0.39",
 ]
 
 [[package]]
@@ -2973,7 +2973,7 @@ dependencies = [
  "proc-macro-error",
  "proc-macro2",
  "quote",
- "syn 2.0.38",
+ "syn 2.0.39",
  "test-case-core",
 ]
 
@@ -2994,7 +2994,7 @@ checksum = "266b2e40bc00e5a6c09c3584011e08b06f123c00362c92b975ba9843aaaa14b8"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.38",
+ "syn 2.0.39",
 ]
 
 [[package]]
@@ -3131,7 +3131,7 @@ checksum = "34704c8d6ebcbc939824180af020566b01a7c01f80641264eba0999f6c2b6be7"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.38",
+ "syn 2.0.39",
 ]
 
 [[package]]
@@ -3349,7 +3349,7 @@ checksum = "3d8c6bba9b149ee82950daefc9623b32bb1dacbfb1890e352f6b887bd582adaf"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.38",
+ "syn 2.0.39",
 ]
 
 [[package]]
@@ -3443,7 +3443,7 @@ dependencies = [
  "once_cell",
  "proc-macro2",
  "quote",
- "syn 2.0.38",
+ "syn 2.0.39",
  "wasm-bindgen-shared",
 ]
 
@@ -3477,7 +3477,7 @@ checksum = "54681b18a46765f095758388f2d0cf16eb8d4169b639ab575a8f5693af210c7b"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.38",
+ "syn 2.0.39",
  "wasm-bindgen-backend",
  "wasm-bindgen-shared",
 ]

Cargo.toml

@@ -13,7 +13,7 @@ license = "MIT"
 
 [workspace.dependencies]
 anyhow = { version = "1.0.69" }
-bitflags = { version = "2.3.1" }
+bitflags = { version = "2.4.1" }
 chrono = { version = "0.4.31", default-features = false, features = ["clock"] }
 clap = { version = "4.4.7", features = ["derive"] }
 colored = { version = "2.0.0" }
@@ -35,14 +35,14 @@ regex = { version = "1.10.2" }
 rustc-hash = { version = "1.1.0" }
 schemars = { version = "0.8.15" }
 serde = { version = "1.0.190", features = ["derive"] }
-serde_json = { version = "1.0.107" }
+serde_json = { version = "1.0.108" }
 shellexpand = { version = "3.0.0" }
 similar = { version = "2.3.0", features = ["inline"] }
 smallvec = { version = "1.11.1" }
 static_assertions = "1.1.0"
 strum = { version = "0.25.0", features = ["strum_macros"] }
 strum_macros = { version = "0.25.3" }
-syn = { version = "2.0.38" }
+syn = { version = "2.0.39" }
 test-case = { version = "3.2.1" }
 thiserror = { version = "1.0.50" }
 toml = { version = "0.7.8" }
@@ -56,7 +56,7 @@ uuid = { version = "1.5.0", features = ["v4", "fast-rng", "macro-diagnostics", "
 wsl = { version = "0.1.0" }
 
 [profile.release]
-lto = "fat"
+lto = "thin"
 codegen-units = 1
 
 [profile.dev.package.insta]

README.md

@@ -415,6 +415,7 @@ Ruff is used by a number of major open-source projects and companies, including:
 - [PDM](https://github.com/pdm-project/pdm)
 - [PaddlePaddle](https://github.com/PaddlePaddle/Paddle)
 - [Pandas](https://github.com/pandas-dev/pandas)
+- [Pillow](https://github.com/python-pillow/Pillow)
 - [Poetry](https://github.com/python-poetry/poetry)
 - [Polars](https://github.com/pola-rs/polars)
 - [PostHog](https://github.com/PostHog/posthog)
@@ -423,6 +424,7 @@ Ruff is used by a number of major open-source projects and companies, including:
 - [PyTorch](https://github.com/pytorch/pytorch)
 - [Pydantic](https://github.com/pydantic/pydantic)
 - [Pylint](https://github.com/PyCQA/pylint)
+- [PyMC-Marketing](https://github.com/pymc-labs/pymc-marketing)
 - [Reflex](https://github.com/reflex-dev/reflex)
 - [Rippling](https://rippling.com)
 - [Robyn](https://github.com/sansyrox/robyn)

_typos.toml

@@ -1,5 +1,6 @@
 [files]
-extend-exclude = ["resources", "snapshots"]
+# https://github.com/crate-ci/typos/issues/868
+extend-exclude = ["**/resources/**/*", "**/snapshots/**/*"]
 
 [default.extend-words]
 hel = "hel"

crates/ruff_benchmark/Cargo.toml

@@ -37,7 +37,7 @@ serde_json.workspace = true
 url = "2.3.1"
 ureq = "2.8.0"
 criterion = { version = "0.5.1", default-features = false }
-codspeed-criterion-compat = { version="2.3.0", default-features = false, optional = true}
+codspeed-criterion-compat = { version="2.3.1", default-features = false, optional = true}
 
 [dev-dependencies]
 ruff_linter.path = "../ruff_linter"

crates/ruff_cli/src/args.rs

@@ -278,7 +278,7 @@ pub struct CheckCommand {
     #[arg(long, help_heading = "Rule configuration", hide = true)]
     pub dummy_variable_rgx: Option<Regex>,
     /// Disable cache reads.
-    #[arg(short, long, help_heading = "Miscellaneous")]
+    #[arg(short, long, env = "RUFF_NO_CACHE", help_heading = "Miscellaneous")]
     pub no_cache: bool,
     /// Ignore all configuration files.
     #[arg(long, conflicts_with = "config", help_heading = "Miscellaneous")]
@@ -374,7 +374,7 @@ pub struct FormatCommand {
     pub config: Option<PathBuf>,
 
     /// Disable cache reads.
-    #[arg(short, long, help_heading = "Miscellaneous")]
+    #[arg(short, long, env = "RUFF_NO_CACHE", help_heading = "Miscellaneous")]
     pub no_cache: bool,
     /// Path to the cache directory.
     #[arg(long, env = "RUFF_CACHE_DIR", help_heading = "Miscellaneous")]

crates/ruff_dev/src/generate_options.rs

@@ -3,6 +3,7 @@
 //! Used for <https://docs.astral.sh/ruff/settings/>.
 use std::fmt::Write;
 
+use ruff_python_trivia::textwrap;
 use ruff_workspace::options::Options;
 use ruff_workspace::options_base::{OptionField, OptionSet, OptionsMetadata, Visit};
 
@@ -125,22 +126,57 @@ fn emit_field(output: &mut String, name: &str, field: &OptionField, parent_set:
     output.push('\n');
     output.push_str(&format!("**Type**: `{}`\n", field.value_type));
     output.push('\n');
-    output.push_str(&format!(
-        "**Example usage**:\n\n```toml\n[tool.ruff{}]\n{}\n```\n",
-        if let Some(set_name) = parent_set.name() {
-            if set_name == "format" {
-                String::from(".format")
-            } else {
-                format!(".lint.{set_name}")
-            }
-        } else {
-            String::new()
-        },
-        field.example
+    output.push_str("**Example usage**:\n\n");
+    output.push_str(&format_tab(
+        "pyproject.toml",
+        &format_header(parent_set, ConfigurationFile::PyprojectToml),
+        field.example,
+    ));
+    output.push_str(&format_tab(
+        "ruff.toml",
+        &format_header(parent_set, ConfigurationFile::RuffToml),
+        field.example,
     ));
     output.push('\n');
 }
 
+fn format_tab(tab_name: &str, header: &str, content: &str) -> String {
+    format!(
+        "=== \"{}\"\n\n    ```toml\n    {}\n{}\n    ```\n",
+        tab_name,
+        header,
+        textwrap::indent(content, "    ")
+    )
+}
+
+fn format_header(parent_set: &Set, configuration: ConfigurationFile) -> String {
+    let fmt = if let Some(set_name) = parent_set.name() {
+        if set_name == "format" {
+            String::from(".format")
+        } else {
+            format!(".lint.{set_name}")
+        }
+    } else {
+        String::new()
+    };
+    match configuration {
+        ConfigurationFile::PyprojectToml => format!("[tool.ruff{fmt}]"),
+        ConfigurationFile::RuffToml => {
+            if fmt.is_empty() {
+                String::new()
+            } else {
+                format!("[{}]", fmt.strip_prefix('.').unwrap())
+            }
+        }
+    }
+}
+
+#[derive(Debug, Copy, Clone)]
+enum ConfigurationFile {
+    PyprojectToml,
+    RuffToml,
+}
+
 #[derive(Default)]
 struct CollectOptionsVisitor {
     groups: Vec<(String, OptionSet)>,

crates/ruff_diagnostics/src/fix.rs

@@ -107,6 +107,30 @@ impl Fix {
         }
     }
 
+    /// Create a new [`Fix`] with the specified [`Applicability`] to apply an [`Edit`] element.
+    pub fn applicable_edit(edit: Edit, applicability: Applicability) -> Self {
+        Self {
+            edits: vec![edit],
+            applicability,
+            isolation_level: IsolationLevel::default(),
+        }
+    }
+
+    /// Create a new [`Fix`] with the specified [`Applicability`] to apply multiple [`Edit`] elements.
+    pub fn applicable_edits(
+        edit: Edit,
+        rest: impl IntoIterator<Item = Edit>,
+        applicability: Applicability,
+    ) -> Self {
+        let mut edits: Vec<Edit> = std::iter::once(edit).chain(rest).collect();
+        edits.sort_by_key(|edit| (edit.start(), edit.end()));
+        Self {
+            edits,
+            applicability,
+            isolation_level: IsolationLevel::default(),
+        }
+    }
+
     /// Return the [`TextSize`] of the first [`Edit`] in the [`Fix`].
     pub fn min_start(&self) -> Option<TextSize> {
         self.edits.first().map(Edit::start)

crates/ruff_linter/resources/test/fixtures/flake8_simplify/SIM118.py

@@ -1,3 +1,5 @@
+obj = {}
+
 key in obj.keys()  # SIM118
 
 key not in obj.keys()  # SIM118

crates/ruff_linter/resources/test/fixtures/flake8_trio/TRIO105.py

@@ -0,0 +1,64 @@
+import trio
+
+
+async def func() -> None:
+    trio.run(foo)  # OK, not async
+
+    # OK
+    await trio.aclose_forcefully(foo)
+    await trio.open_file(foo)
+    await trio.open_ssl_over_tcp_listeners(foo, foo)
+    await trio.open_ssl_over_tcp_stream(foo, foo)
+    await trio.open_tcp_listeners(foo)
+    await trio.open_tcp_stream(foo, foo)
+    await trio.open_unix_socket(foo)
+    await trio.run_process(foo)
+    await trio.sleep(5)
+    await trio.sleep_until(5)
+    await trio.lowlevel.cancel_shielded_checkpoint()
+    await trio.lowlevel.checkpoint()
+    await trio.lowlevel.checkpoint_if_cancelled()
+    await trio.lowlevel.open_process(foo)
+    await trio.lowlevel.permanently_detach_coroutine_object(foo)
+    await trio.lowlevel.reattach_detached_coroutine_object(foo, foo)
+    await trio.lowlevel.temporarily_detach_coroutine_object(foo)
+    await trio.lowlevel.wait_readable(foo)
+    await trio.lowlevel.wait_task_rescheduled(foo)
+    await trio.lowlevel.wait_writable(foo)
+
+    # TRIO105
+    trio.aclose_forcefully(foo)
+    trio.open_file(foo)
+    trio.open_ssl_over_tcp_listeners(foo, foo)
+    trio.open_ssl_over_tcp_stream(foo, foo)
+    trio.open_tcp_listeners(foo)
+    trio.open_tcp_stream(foo, foo)
+    trio.open_unix_socket(foo)
+    trio.run_process(foo)
+    trio.serve_listeners(foo, foo)
+    trio.serve_ssl_over_tcp(foo, foo, foo)
+    trio.serve_tcp(foo, foo)
+    trio.sleep(foo)
+    trio.sleep_forever()
+    trio.sleep_until(foo)
+    trio.lowlevel.cancel_shielded_checkpoint()
+    trio.lowlevel.checkpoint()
+    trio.lowlevel.checkpoint_if_cancelled()
+    trio.lowlevel.open_process()
+    trio.lowlevel.permanently_detach_coroutine_object(foo)
+    trio.lowlevel.reattach_detached_coroutine_object(foo, foo)
+    trio.lowlevel.temporarily_detach_coroutine_object(foo)
+    trio.lowlevel.wait_readable(foo)
+    trio.lowlevel.wait_task_rescheduled(foo)
+    trio.lowlevel.wait_writable(foo)
+
+    async with await trio.open_file(foo):  # Ok
+        pass
+
+    async with trio.open_file(foo):  # TRIO105
+        pass
+
+
+def func() -> None:
+    # TRIO105 (without fix)
+    trio.open_file(foo)

crates/ruff_linter/resources/test/fixtures/flake8_trio/TRIO115.py

@@ -0,0 +1,28 @@
+import trio
+from trio import sleep
+
+
+async def func():
+    await trio.sleep(0)  # TRIO115
+    await trio.sleep(1)  # OK
+    await trio.sleep(0, 1)  # OK
+    await trio.sleep(...)  # OK
+    await trio.sleep()  # OK
+
+    trio.sleep(0)  # TRIO115
+    foo = 0
+    trio.sleep(foo)  # TRIO115
+    trio.sleep(1)  # OK
+    time.sleep(0)  # OK
+
+    sleep(0)  # TRIO115
+
+    bar = "bar"
+    trio.sleep(bar)
+
+
+trio.sleep(0)  # TRIO115
+
+
+def func():
+    trio.run(trio.sleep(0))  # TRIO115

crates/ruff_linter/resources/test/fixtures/pycodestyle/E70.py

@@ -69,3 +69,5 @@ while 1:
 #: E701:2:3
 a = \
   5;
+#:
+with x(y) as z: ...

crates/ruff_linter/resources/test/fixtures/pycodestyle/E721.py

@@ -4,6 +4,9 @@ if type(res) == type(42):
 #: E721
 if type(res) != type(""):
     pass
+#: E721
+if type(res) == memoryview:
+    pass
 #: Okay
 import types
 
@@ -47,6 +50,14 @@ if isinstance(res, str):
     pass
 if isinstance(res, types.MethodType):
     pass
+if isinstance(res, memoryview):
+    pass
+#: Okay
+if type(res) is type:
+    pass
+#: E721
+if type(res) == type:
+    pass
 #: Okay
 def func_histype(a, b, c):
     pass

crates/ruff_linter/resources/test/fixtures/pydocstyle/D301.py

@@ -31,3 +31,7 @@ def make_unique_pod_id(pod_id: str) -> str | None:
     :param pod_id: requested pod name
     :return: ``str`` valid Pod name of appropriate length
     """
+
+
+def shouldnt_add_raw_here2():
+    u"Sum\\mary."

crates/ruff_linter/resources/test/fixtures/pyflakes/F841_1.py

@@ -1,5 +1,5 @@
 def f(tup):
-    x, y = tup  # this does NOT trigger F841
+    x, y = tup
 
 
 def f():
@@ -7,17 +7,17 @@ def f():
 
 
 def f():
-    (x, y) = coords = 1, 2  # this does NOT trigger F841
+    (x, y) = coords = 1, 2
     if x > 1:
         print(coords)
 
 
 def f():
-    (x, y) = coords = 1, 2  # this triggers F841 on coords
+    (x, y) = coords = 1, 2
 
 
 def f():
-    coords = (x, y) = 1, 2  # this triggers F841 on coords
+    coords = (x, y) = 1, 2
 
 
 def f():

crates/ruff_linter/resources/test/fixtures/pyflakes/F841_4.py

@@ -0,0 +1,32 @@
+"""Test fix for issue #8441.
+
+Ref: https://github.com/astral-sh/ruff/issues/8441
+"""
+
+
+def foo():
+    ...
+
+
+def bar():
+    a = foo()
+    b, c = foo()
+
+
+def baz():
+    d, _e = foo()
+    print(d)
+
+
+def qux():
+    f, _ = foo()
+    print(f)
+
+
+def quux():
+    g, h = foo()
+    print(g, h)
+
+
+def quuz():
+    _i, _j = foo()

crates/ruff_linter/resources/test/fixtures/refurb/FURB131.py

@@ -43,6 +43,12 @@ def yes_four(x: Dict[int, str]):
     del x[:]
 
 
+def yes_five(x: Dict[int, str]):
+    # FURB131
+    del x[:]
+
+    x = 1
+
 # these should not
 
 del names["key"]

crates/ruff_linter/resources/test/fixtures/refurb/FURB169.py

@@ -0,0 +1,67 @@
+foo = None
+
+# Error.
+
+type(foo) is type(None)
+
+type(None) is type(foo)
+
+type(None) is type(None)
+
+type(foo) is not type(None)
+
+type(None) is not type(foo)
+
+type(None) is not type(None)
+
+type(foo) == type(None)
+
+type(None) == type(foo)
+
+type(None) == type(None)
+
+type(foo) != type(None)
+
+type(None) != type(foo)
+
+type(None) != type(None)
+
+# Ok.
+
+foo is None
+
+foo is not None
+
+None is foo
+
+None is not foo
+
+None is None
+
+None is not None
+
+foo is type(None)
+
+type(foo) is None
+
+type(None) is None
+
+foo is not type(None)
+
+type(foo) is not None
+
+type(None) is not None
+
+foo == type(None)
+
+type(foo) == None
+
+type(None) == None
+
+foo != type(None)
+
+type(foo) != None
+
+type(None) != None
+
+type(foo) > type(None)

crates/ruff_linter/src/checkers/ast/analyze/expression.rs

@@ -15,8 +15,8 @@ use crate::rules::{
     flake8_comprehensions, flake8_datetimez, flake8_debugger, flake8_django,
     flake8_future_annotations, flake8_gettext, flake8_implicit_str_concat, flake8_logging,
     flake8_logging_format, flake8_pie, flake8_print, flake8_pyi, flake8_pytest_style, flake8_self,
-    flake8_simplify, flake8_tidy_imports, flake8_use_pathlib, flynt, numpy, pandas_vet,
-    pep8_naming, pycodestyle, pyflakes, pygrep_hooks, pylint, pyupgrade, refurb, ruff,
+    flake8_simplify, flake8_tidy_imports, flake8_trio, flake8_use_pathlib, flynt, numpy,
+    pandas_vet, pep8_naming, pycodestyle, pyflakes, pygrep_hooks, pylint, pyupgrade, refurb, ruff,
 };
 use crate::settings::types::PythonVersion;
 
@@ -926,6 +926,12 @@ pub(crate) fn expression(expr: &Expr, checker: &mut Checker) {
             if checker.enabled(Rule::ImplicitCwd) {
                 refurb::rules::no_implicit_cwd(checker, call);
             }
+            if checker.enabled(Rule::TrioSyncCall) {
+                flake8_trio::rules::sync_call(checker, call);
+            }
+            if checker.enabled(Rule::TrioZeroSleepCall) {
+                flake8_trio::rules::zero_sleep_call(checker, call);
+            }
         }
         Expr::Dict(
             dict @ ast::ExprDict {
@@ -1235,6 +1241,9 @@ pub(crate) fn expression(expr: &Expr, checker: &mut Checker) {
                     comparators,
                 );
             }
+            if checker.enabled(Rule::TypeNoneComparison) {
+                refurb::rules::type_none_comparison(checker, compare);
+            }
             if checker.enabled(Rule::SingleItemMembershipTest) {
                 refurb::rules::single_item_membership_test(checker, expr, left, ops, comparators);
             }

crates/ruff_linter/src/codes.rs

@@ -292,6 +292,8 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<(RuleGroup, Rule)> {
 
         // flake8-trio
         (Flake8Trio, "100") => (RuleGroup::Preview, rules::flake8_trio::rules::TrioTimeoutWithoutAwait),
+        (Flake8Trio, "105") => (RuleGroup::Preview, rules::flake8_trio::rules::TrioSyncCall),
+        (Flake8Trio, "115") => (RuleGroup::Preview, rules::flake8_trio::rules::TrioZeroSleepCall),
 
         // flake8-builtins
         (Flake8Builtins, "001") => (RuleGroup::Stable, rules::flake8_builtins::rules::BuiltinVariableShadowing),
@@ -944,6 +946,7 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<(RuleGroup, Rule)> {
         (Refurb, "145") => (RuleGroup::Preview, rules::refurb::rules::SliceCopy),
         (Refurb, "148") => (RuleGroup::Preview, rules::refurb::rules::UnnecessaryEnumerate),
         (Refurb, "168") => (RuleGroup::Preview, rules::refurb::rules::IsinstanceTypeNone),
+        (Refurb, "169") => (RuleGroup::Preview, rules::refurb::rules::TypeNoneComparison),
         (Refurb, "171") => (RuleGroup::Preview, rules::refurb::rules::SingleItemMembershipTest),
         (Refurb, "177") => (RuleGroup::Preview, rules::refurb::rules::ImplicitCwd),
 

crates/ruff_linter/src/rules/eradicate/detection.rs

@@ -163,11 +163,15 @@ mod tests {
             "# ( user_content_type , _ )= TimelineEvent.objects.using(db_alias).get_or_create(",
             &[]
         ));
-        assert!(comment_contains_code(
+        assert!(comment_contains_code("# )", &[]));
+
+        // This used to return true, but our parser has gotten a bit better
+        // at rejecting invalid Python syntax. And indeed, this is not valid
+        // Python code.
+        assert!(!comment_contains_code(
             "#     app_label=\"core\", model=\"user\"",
             &[]
         ));
-        assert!(comment_contains_code("# )", &[]));
 
         // TODO(charlie): This should be `true` under aggressive mode.
         assert!(!comment_contains_code("#def foo():", &[]));

crates/ruff_linter/src/rules/flake8_bugbear/rules/assert_false.rs

@@ -27,6 +27,11 @@ use crate::checkers::ast::Checker;
 /// raise AssertionError
 /// ```
 ///
+/// ## Fix safety
+/// This rule's fix is marked as unsafe, as changing an `assert` to a
+/// `raise` will change the behavior of your program when running in
+/// optimized mode (`python -O`).
+///
 /// ## References
 /// - [Python documentation: `assert`](https://docs.python.org/3/reference/simple_stmts.html#the-assert-statement)
 #[violation]

crates/ruff_linter/src/rules/flake8_bugbear/rules/function_call_in_argument_default.rs

@@ -50,6 +50,16 @@ use crate::checkers::ast::Checker;
 ///     return arg
 /// ```
 ///
+/// If the use of a singleton is intentional, assign the result call to a
+/// module-level variable, and use that variable in the default argument:
+/// ```python
+/// ERROR = ValueError("Hosts weren't successfully added")
+///
+///
+/// def add_host(error: Exception = ERROR) -> None:
+///     ...
+/// ```
+///
 /// ## Options
 /// - `flake8-bugbear.extend-immutable-calls`
 #[violation]
@@ -62,9 +72,9 @@ impl Violation for FunctionCallInDefaultArgument {
     fn message(&self) -> String {
         let FunctionCallInDefaultArgument { name } = self;
         if let Some(name) = name {
-            format!("Do not perform function call `{name}` in argument defaults")
+            format!("Do not perform function call `{name}` in argument defaults; instead, perform the call within the function, or read the default from a module-level singleton variable")
         } else {
-            format!("Do not perform function call in argument defaults")
+            format!("Do not perform function call in argument defaults; instead, perform the call within the function, or read the default from a module-level singleton variable")
         }
     }
 }

crates/ruff_linter/src/rules/flake8_bugbear/snapshots/ruff_linter__rules__flake8_bugbear__tests__B008_B006_B008.py.snap

@@ -1,7 +1,7 @@
 ---
 source: crates/ruff_linter/src/rules/flake8_bugbear/mod.rs
 ---
-B006_B008.py:102:61: B008 Do not perform function call `range` in argument defaults
+B006_B008.py:102:61: B008 Do not perform function call `range` in argument defaults; instead, perform the call within the function, or read the default from a module-level singleton variable
     |
 101 | # N.B. we're also flagging the function call in the comprehension
 102 | def list_comprehension_also_not_okay(default=[i**2 for i in range(3)]):
@@ -9,21 +9,21 @@ B006_B008.py:102:61: B008 Do not perform function call `range` in argument defau
 103 |     pass
     |
 
-B006_B008.py:106:64: B008 Do not perform function call `range` in argument defaults
+B006_B008.py:106:64: B008 Do not perform function call `range` in argument defaults; instead, perform the call within the function, or read the default from a module-level singleton variable
     |
 106 | def dict_comprehension_also_not_okay(default={i: i**2 for i in range(3)}):
     |                                                                ^^^^^^^^ B008
 107 |     pass
     |
 
-B006_B008.py:110:60: B008 Do not perform function call `range` in argument defaults
+B006_B008.py:110:60: B008 Do not perform function call `range` in argument defaults; instead, perform the call within the function, or read the default from a module-level singleton variable
     |
 110 | def set_comprehension_also_not_okay(default={i**2 for i in range(3)}):
     |                                                            ^^^^^^^^ B008
 111 |     pass
     |
 
-B006_B008.py:126:39: B008 Do not perform function call `time.time` in argument defaults
+B006_B008.py:126:39: B008 Do not perform function call `time.time` in argument defaults; instead, perform the call within the function, or read the default from a module-level singleton variable
     |
 124 | # B008
 125 | # Flag function calls as default args (including if they are part of a sub-expression)
@@ -32,21 +32,21 @@ B006_B008.py:126:39: B008 Do not perform function call `time.time` in argument d
 127 |     ...
     |
 
-B006_B008.py:130:12: B008 Do not perform function call `dt.datetime.now` in argument defaults
+B006_B008.py:130:12: B008 Do not perform function call `dt.datetime.now` in argument defaults; instead, perform the call within the function, or read the default from a module-level singleton variable
     |
 130 | def f(when=dt.datetime.now() + dt.timedelta(days=7)):
     |            ^^^^^^^^^^^^^^^^^ B008
 131 |     pass
     |
 
-B006_B008.py:134:30: B008 Do not perform function call in argument defaults
+B006_B008.py:134:30: B008 Do not perform function call in argument defaults; instead, perform the call within the function, or read the default from a module-level singleton variable
     |
 134 | def can_even_catch_lambdas(a=(lambda x: x)()):
     |                              ^^^^^^^^^^^^^^^ B008
 135 |     ...
     |
 
-B006_B008.py:239:31: B008 Do not perform function call `dt.datetime.now` in argument defaults
+B006_B008.py:239:31: B008 Do not perform function call `dt.datetime.now` in argument defaults; instead, perform the call within the function, or read the default from a module-level singleton variable
     |
 237 | # B006 and B008
 238 | # We should handle arbitrary nesting of these B008.
@@ -55,7 +55,7 @@ B006_B008.py:239:31: B008 Do not perform function call `dt.datetime.now` in argu
 240 |     pass
     |
 
-B006_B008.py:245:22: B008 Do not perform function call `map` in argument defaults
+B006_B008.py:245:22: B008 Do not perform function call `map` in argument defaults; instead, perform the call within the function, or read the default from a module-level singleton variable
     |
 243 | # Don't flag nested B006 since we can't guarantee that
 244 | # it isn't made mutable by the outer operation.
@@ -64,7 +64,7 @@ B006_B008.py:245:22: B008 Do not perform function call `map` in argument default
 246 |     pass
     |
 
-B006_B008.py:250:19: B008 Do not perform function call `random.randint` in argument defaults
+B006_B008.py:250:19: B008 Do not perform function call `random.randint` in argument defaults; instead, perform the call within the function, or read the default from a module-level singleton variable
     |
 249 | # B008-ception.
 250 | def nested_b008(a=random.randint(0, dt.datetime.now().year)):
@@ -72,7 +72,7 @@ B006_B008.py:250:19: B008 Do not perform function call `random.randint` in argum
 251 |     pass
     |
 
-B006_B008.py:250:37: B008 Do not perform function call `dt.datetime.now` in argument defaults
+B006_B008.py:250:37: B008 Do not perform function call `dt.datetime.now` in argument defaults; instead, perform the call within the function, or read the default from a module-level singleton variable
     |
 249 | # B008-ception.
 250 | def nested_b008(a=random.randint(0, dt.datetime.now().year)):

crates/ruff_linter/src/rules/flake8_bugbear/snapshots/ruff_linter__rules__flake8_bugbear__tests__extend_immutable_calls_arg_default.snap

@@ -1,7 +1,7 @@
 ---
 source: crates/ruff_linter/src/rules/flake8_bugbear/mod.rs
 ---
-B008_extended.py:24:51: B008 Do not perform function call `Depends` in argument defaults
+B008_extended.py:24:51: B008 Do not perform function call `Depends` in argument defaults; instead, perform the call within the function, or read the default from a module-level singleton variable
    |
 24 | def error_due_to_missing_import(data: List[str] = Depends(None)):
    |                                                   ^^^^^^^^^^^^^ B008

crates/ruff_linter/src/rules/flake8_comprehensions/rules/unnecessary_call_around_sorted.rs

@@ -1,4 +1,4 @@
-use ruff_diagnostics::{AlwaysFixableViolation, Diagnostic, Fix};
+use ruff_diagnostics::{AlwaysFixableViolation, Applicability, Diagnostic, Fix};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::{self as ast, Expr};
 use ruff_text_size::Ranged;
@@ -83,13 +83,14 @@ pub(crate) fn unnecessary_call_around_sorted(
         expr.range(),
     );
     diagnostic.try_set_fix(|| {
-        let edit =
-            fixes::fix_unnecessary_call_around_sorted(expr, checker.locator(), checker.stylist())?;
-        if outer.id == "reversed" {
-            Ok(Fix::unsafe_edit(edit))
-        } else {
-            Ok(Fix::safe_edit(edit))
-        }
+        Ok(Fix::applicable_edit(
+            fixes::fix_unnecessary_call_around_sorted(expr, checker.locator(), checker.stylist())?,
+            if outer.id == "reversed" {
+                Applicability::Unsafe
+            } else {
+                Applicability::Safe
+            },
+        ))
     });
     checker.diagnostics.push(diagnostic);
 }

crates/ruff_linter/src/rules/flake8_raise/rules/unnecessary_paren_on_raise_exception.rs

@@ -1,4 +1,4 @@
-use ruff_diagnostics::{AlwaysFixableViolation, Diagnostic, Edit, Fix};
+use ruff_diagnostics::{AlwaysFixableViolation, Applicability, Diagnostic, Edit, Fix};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::{self as ast, Expr};
 use ruff_python_semantic::BindingKind;
@@ -103,17 +103,23 @@ pub(crate) fn unnecessary_paren_on_raise_exception(checker: &mut Checker, expr:
             .next()
             .is_some_and(char::is_alphanumeric)
         {
-            diagnostic.set_fix(if exception_type.is_some() {
-                Fix::safe_edit(Edit::range_replacement(" ".to_string(), arguments.range()))
-            } else {
-                Fix::unsafe_edit(Edit::range_replacement(" ".to_string(), arguments.range()))
-            });
+            diagnostic.set_fix(Fix::applicable_edit(
+                Edit::range_replacement(" ".to_string(), arguments.range()),
+                if exception_type.is_some() {
+                    Applicability::Safe
+                } else {
+                    Applicability::Unsafe
+                },
+            ));
         } else {
-            diagnostic.set_fix(if exception_type.is_some() {
-                Fix::safe_edit(Edit::range_deletion(arguments.range()))
-            } else {
-                Fix::unsafe_edit(Edit::range_deletion(arguments.range()))
-            });
+            diagnostic.set_fix(Fix::applicable_edit(
+                Edit::range_deletion(arguments.range()),
+                if exception_type.is_some() {
+                    Applicability::Safe
+                } else {
+                    Applicability::Unsafe
+                },
+            ));
         }
 
         checker.diagnostics.push(diagnostic);

crates/ruff_linter/src/rules/flake8_simplify/mod.rs

@@ -55,6 +55,7 @@ mod tests {
         Ok(())
     }
 
+    #[test_case(Rule::InDictKeys, Path::new("SIM118.py"))]
     #[test_case(Rule::IfElseBlockInsteadOfDictGet, Path::new("SIM401.py"))]
     fn preview_rules(rule_code: Rule, path: &Path) -> Result<()> {
         let snapshot = format!(

crates/ruff_linter/src/rules/flake8_simplify/rules/key_in_dict.rs

@@ -1,9 +1,10 @@
-use ruff_diagnostics::Edit;
 use ruff_diagnostics::{AlwaysFixableViolation, Diagnostic, Fix};
+use ruff_diagnostics::{Applicability, Edit};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::parenthesize::parenthesized_range;
 use ruff_python_ast::AnyNodeRef;
 use ruff_python_ast::{self as ast, Arguments, CmpOp, Comprehension, Expr};
+use ruff_python_semantic::analyze::typing;
 use ruff_python_trivia::{SimpleTokenKind, SimpleTokenizer};
 use ruff_text_size::{Ranged, TextRange};
 
@@ -27,8 +28,19 @@ use crate::checkers::ast::Checker;
 /// key in foo
 /// ```
 ///
+/// ## Fix safety
+/// Given `key in obj.keys()`, `obj` _could_ be a dictionary, or it could be
+/// another type that defines a `.keys()` method. In the latter case, removing
+/// the `.keys()` attribute could lead to a runtime error.
+///
+/// As such, this rule's fixes are marked as unsafe. In [preview], though,
+/// fixes are marked as safe when Ruff can determine that `obj` is a
+/// dictionary.
+///
 /// ## References
 /// - [Python documentation: Mapping Types](https://docs.python.org/3/library/stdtypes.html#mapping-types-dict)
+///
+/// [preview]: https://docs.astral.sh/ruff/preview/
 #[violation]
 pub struct InDictKeys {
     operator: String,
@@ -113,6 +125,28 @@ fn key_in_dict(
         .skip_trivia()
         .find(|token| token.kind == SimpleTokenKind::Dot)
     {
+        // The fix is only safe if we know the expression is a dictionary, since other types
+        // can define a `.keys()` method.
+        let applicability = if checker.settings.preview.is_enabled() {
+            let is_dict = value.as_name_expr().is_some_and(|name| {
+                let Some(binding) = checker
+                    .semantic()
+                    .only_binding(name)
+                    .map(|id| checker.semantic().binding(id))
+                else {
+                    return false;
+                };
+                typing::is_dict(binding, checker.semantic())
+            });
+            if is_dict {
+                Applicability::Safe
+            } else {
+                Applicability::Unsafe
+            }
+        } else {
+            Applicability::Unsafe
+        };
+
         // If the `.keys()` is followed by (e.g.) a keyword, we need to insert a space,
         // since we're removing parentheses, which could lead to invalid syntax, as in:
         // ```python
@@ -126,12 +160,15 @@ fn key_in_dict(
             .next()
             .is_some_and(|char| char.is_ascii_alphabetic())
         {
-            diagnostic.set_fix(Fix::unsafe_edit(Edit::range_replacement(
-                " ".to_string(),
-                range,
-            )));
+            diagnostic.set_fix(Fix::applicable_edit(
+                Edit::range_replacement(" ".to_string(), range),
+                applicability,
+            ));
         } else {
-            diagnostic.set_fix(Fix::unsafe_edit(Edit::range_deletion(range)));
+            diagnostic.set_fix(Fix::applicable_edit(
+                Edit::range_deletion(range),
+                applicability,
+            ));
         }
     }
     checker.diagnostics.push(diagnostic);

crates/ruff_linter/src/rules/flake8_simplify/snapshots/ruff_linter__rules__flake8_simplify__tests__SIM118_SIM118.py.snap

@@ -1,396 +1,401 @@
 ---
 source: crates/ruff_linter/src/rules/flake8_simplify/mod.rs
 ---
-SIM118.py:1:1: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
+SIM118.py:3:1: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
   |
-1 | key in obj.keys()  # SIM118
+1 | obj = {}
+2 | 
+3 | key in obj.keys()  # SIM118
   | ^^^^^^^^^^^^^^^^^ SIM118
-2 | 
-3 | key not in obj.keys()  # SIM118
+4 | 
+5 | key not in obj.keys()  # SIM118
   |
   = help: Remove `.keys()`
 
 ℹ Suggested fix
-1   |-key in obj.keys()  # SIM118
-  1 |+key in obj  # SIM118
+1 1 | obj = {}
 2 2 | 
-3 3 | key not in obj.keys()  # SIM118
+3   |-key in obj.keys()  # SIM118
+  3 |+key in obj  # SIM118
 4 4 | 
+5 5 | key not in obj.keys()  # SIM118
+6 6 | 
 
-SIM118.py:3:1: SIM118 [*] Use `key not in dict` instead of `key not in dict.keys()`
+SIM118.py:5:1: SIM118 [*] Use `key not in dict` instead of `key not in dict.keys()`
   |
-1 | key in obj.keys()  # SIM118
-2 | 
-3 | key not in obj.keys()  # SIM118
+3 | key in obj.keys()  # SIM118
+4 | 
+5 | key not in obj.keys()  # SIM118
   | ^^^^^^^^^^^^^^^^^^^^^ SIM118
-4 | 
-5 | foo["bar"] in obj.keys()  # SIM118
+6 | 
+7 | foo["bar"] in obj.keys()  # SIM118
   |
   = help: Remove `.keys()`
 
 ℹ Suggested fix
-1 1 | key in obj.keys()  # SIM118
 2 2 | 
-3   |-key not in obj.keys()  # SIM118
-  3 |+key not in obj  # SIM118
+3 3 | key in obj.keys()  # SIM118
 4 4 | 
-5 5 | foo["bar"] in obj.keys()  # SIM118
+5   |-key not in obj.keys()  # SIM118
+  5 |+key not in obj  # SIM118
 6 6 | 
+7 7 | foo["bar"] in obj.keys()  # SIM118
+8 8 | 
 
-SIM118.py:5:1: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
+SIM118.py:7:1: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
   |
-3 | key not in obj.keys()  # SIM118
-4 | 
-5 | foo["bar"] in obj.keys()  # SIM118
+5 | key not in obj.keys()  # SIM118
+6 | 
+7 | foo["bar"] in obj.keys()  # SIM118
   | ^^^^^^^^^^^^^^^^^^^^^^^^ SIM118
-6 | 
-7 | foo["bar"] not in obj.keys()  # SIM118
-  |
-  = help: Remove `.keys()`
-
-ℹ Suggested fix
-2 2 | 
-3 3 | key not in obj.keys()  # SIM118
-4 4 | 
-5   |-foo["bar"] in obj.keys()  # SIM118
-  5 |+foo["bar"] in obj  # SIM118
-6 6 | 
-7 7 | foo["bar"] not in obj.keys()  # SIM118
-8 8 | 
-
-SIM118.py:7:1: SIM118 [*] Use `key not in dict` instead of `key not in dict.keys()`
-  |
-5 | foo["bar"] in obj.keys()  # SIM118
-6 | 
-7 | foo["bar"] not in obj.keys()  # SIM118
-  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ SIM118
 8 | 
-9 | foo['bar'] in obj.keys()  # SIM118
+9 | foo["bar"] not in obj.keys()  # SIM118
   |
   = help: Remove `.keys()`
 
 ℹ Suggested fix
 4 4 | 
-5 5 | foo["bar"] in obj.keys()  # SIM118
+5 5 | key not in obj.keys()  # SIM118
 6 6 | 
-7   |-foo["bar"] not in obj.keys()  # SIM118
-  7 |+foo["bar"] not in obj  # SIM118
+7   |-foo["bar"] in obj.keys()  # SIM118
+  7 |+foo["bar"] in obj  # SIM118
 8 8 | 
-9 9 | foo['bar'] in obj.keys()  # SIM118
+9 9 | foo["bar"] not in obj.keys()  # SIM118
 10 10 | 
 
-SIM118.py:9:1: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
+SIM118.py:9:1: SIM118 [*] Use `key not in dict` instead of `key not in dict.keys()`
    |
- 7 | foo["bar"] not in obj.keys()  # SIM118
+ 7 | foo["bar"] in obj.keys()  # SIM118
  8 | 
- 9 | foo['bar'] in obj.keys()  # SIM118
-   | ^^^^^^^^^^^^^^^^^^^^^^^^ SIM118
+ 9 | foo["bar"] not in obj.keys()  # SIM118
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ SIM118
 10 | 
-11 | foo['bar'] not in obj.keys()  # SIM118
+11 | foo['bar'] in obj.keys()  # SIM118
    |
    = help: Remove `.keys()`
 
 ℹ Suggested fix
 6  6  | 
-7  7  | foo["bar"] not in obj.keys()  # SIM118
+7  7  | foo["bar"] in obj.keys()  # SIM118
 8  8  | 
-9     |-foo['bar'] in obj.keys()  # SIM118
-   9  |+foo['bar'] in obj  # SIM118
+9     |-foo["bar"] not in obj.keys()  # SIM118
+   9  |+foo["bar"] not in obj  # SIM118
 10 10 | 
-11 11 | foo['bar'] not in obj.keys()  # SIM118
+11 11 | foo['bar'] in obj.keys()  # SIM118
 12 12 | 
 
-SIM118.py:11:1: SIM118 [*] Use `key not in dict` instead of `key not in dict.keys()`
+SIM118.py:11:1: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
    |
- 9 | foo['bar'] in obj.keys()  # SIM118
+ 9 | foo["bar"] not in obj.keys()  # SIM118
 10 | 
-11 | foo['bar'] not in obj.keys()  # SIM118
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ SIM118
+11 | foo['bar'] in obj.keys()  # SIM118
+   | ^^^^^^^^^^^^^^^^^^^^^^^^ SIM118
 12 | 
-13 | foo() in obj.keys()  # SIM118
+13 | foo['bar'] not in obj.keys()  # SIM118
    |
    = help: Remove `.keys()`
 
 ℹ Suggested fix
 8  8  | 
-9  9  | foo['bar'] in obj.keys()  # SIM118
+9  9  | foo["bar"] not in obj.keys()  # SIM118
 10 10 | 
-11    |-foo['bar'] not in obj.keys()  # SIM118
-   11 |+foo['bar'] not in obj  # SIM118
+11    |-foo['bar'] in obj.keys()  # SIM118
+   11 |+foo['bar'] in obj  # SIM118
 12 12 | 
-13 13 | foo() in obj.keys()  # SIM118
+13 13 | foo['bar'] not in obj.keys()  # SIM118
 14 14 | 
 
-SIM118.py:13:1: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
+SIM118.py:13:1: SIM118 [*] Use `key not in dict` instead of `key not in dict.keys()`
    |
-11 | foo['bar'] not in obj.keys()  # SIM118
+11 | foo['bar'] in obj.keys()  # SIM118
 12 | 
-13 | foo() in obj.keys()  # SIM118
-   | ^^^^^^^^^^^^^^^^^^^ SIM118
+13 | foo['bar'] not in obj.keys()  # SIM118
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ SIM118
 14 | 
-15 | foo() not in obj.keys()  # SIM118
+15 | foo() in obj.keys()  # SIM118
    |
    = help: Remove `.keys()`
 
 ℹ Suggested fix
 10 10 | 
-11 11 | foo['bar'] not in obj.keys()  # SIM118
+11 11 | foo['bar'] in obj.keys()  # SIM118
 12 12 | 
-13    |-foo() in obj.keys()  # SIM118
-   13 |+foo() in obj  # SIM118
+13    |-foo['bar'] not in obj.keys()  # SIM118
+   13 |+foo['bar'] not in obj  # SIM118
 14 14 | 
-15 15 | foo() not in obj.keys()  # SIM118
+15 15 | foo() in obj.keys()  # SIM118
 16 16 | 
 
-SIM118.py:15:1: SIM118 [*] Use `key not in dict` instead of `key not in dict.keys()`
+SIM118.py:15:1: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
    |
-13 | foo() in obj.keys()  # SIM118
+13 | foo['bar'] not in obj.keys()  # SIM118
 14 | 
-15 | foo() not in obj.keys()  # SIM118
-   | ^^^^^^^^^^^^^^^^^^^^^^^ SIM118
+15 | foo() in obj.keys()  # SIM118
+   | ^^^^^^^^^^^^^^^^^^^ SIM118
 16 | 
-17 | for key in obj.keys():  # SIM118
+17 | foo() not in obj.keys()  # SIM118
    |
    = help: Remove `.keys()`
 
 ℹ Suggested fix
 12 12 | 
-13 13 | foo() in obj.keys()  # SIM118
+13 13 | foo['bar'] not in obj.keys()  # SIM118
 14 14 | 
-15    |-foo() not in obj.keys()  # SIM118
-   15 |+foo() not in obj  # SIM118
+15    |-foo() in obj.keys()  # SIM118
+   15 |+foo() in obj  # SIM118
 16 16 | 
-17 17 | for key in obj.keys():  # SIM118
-18 18 |     pass
+17 17 | foo() not in obj.keys()  # SIM118
+18 18 | 
 
-SIM118.py:17:5: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
+SIM118.py:17:1: SIM118 [*] Use `key not in dict` instead of `key not in dict.keys()`
    |
-15 | foo() not in obj.keys()  # SIM118
+15 | foo() in obj.keys()  # SIM118
 16 | 
-17 | for key in obj.keys():  # SIM118
-   |     ^^^^^^^^^^^^^^^^^ SIM118
-18 |     pass
+17 | foo() not in obj.keys()  # SIM118
+   | ^^^^^^^^^^^^^^^^^^^^^^^ SIM118
+18 | 
+19 | for key in obj.keys():  # SIM118
    |
    = help: Remove `.keys()`
 
 ℹ Suggested fix
 14 14 | 
-15 15 | foo() not in obj.keys()  # SIM118
+15 15 | foo() in obj.keys()  # SIM118
 16 16 | 
-17    |-for key in obj.keys():  # SIM118
-   17 |+for key in obj:  # SIM118
-18 18 |     pass
-19 19 | 
-20 20 | for key in list(obj.keys()):
+17    |-foo() not in obj.keys()  # SIM118
+   17 |+foo() not in obj  # SIM118
+18 18 | 
+19 19 | for key in obj.keys():  # SIM118
+20 20 |     pass
 
-SIM118.py:24:8: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
+SIM118.py:19:5: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
    |
-22 |         del obj[key]
-23 | 
-24 | [k for k in obj.keys()]  # SIM118
-   |        ^^^^^^^^^^^^^^^ SIM118
-25 | 
-26 | {k for k in obj.keys()}  # SIM118
+17 | foo() not in obj.keys()  # SIM118
+18 | 
+19 | for key in obj.keys():  # SIM118
+   |     ^^^^^^^^^^^^^^^^^ SIM118
+20 |     pass
    |
    = help: Remove `.keys()`
 
 ℹ Suggested fix
-21 21 |     if some_property(key):
-22 22 |         del obj[key]
-23 23 | 
-24    |-[k for k in obj.keys()]  # SIM118
-   24 |+[k for k in obj]  # SIM118
-25 25 | 
-26 26 | {k for k in obj.keys()}  # SIM118
-27 27 | 
+16 16 | 
+17 17 | foo() not in obj.keys()  # SIM118
+18 18 | 
+19    |-for key in obj.keys():  # SIM118
+   19 |+for key in obj:  # SIM118
+20 20 |     pass
+21 21 | 
+22 22 | for key in list(obj.keys()):
 
 SIM118.py:26:8: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
    |
-24 | [k for k in obj.keys()]  # SIM118
+24 |         del obj[key]
 25 | 
-26 | {k for k in obj.keys()}  # SIM118
+26 | [k for k in obj.keys()]  # SIM118
    |        ^^^^^^^^^^^^^^^ SIM118
 27 | 
-28 | {k: k for k in obj.keys()}  # SIM118
+28 | {k for k in obj.keys()}  # SIM118
    |
    = help: Remove `.keys()`
 
 ℹ Suggested fix
-23 23 | 
-24 24 | [k for k in obj.keys()]  # SIM118
+23 23 |     if some_property(key):
+24 24 |         del obj[key]
 25 25 | 
-26    |-{k for k in obj.keys()}  # SIM118
-   26 |+{k for k in obj}  # SIM118
+26    |-[k for k in obj.keys()]  # SIM118
+   26 |+[k for k in obj]  # SIM118
 27 27 | 
-28 28 | {k: k for k in obj.keys()}  # SIM118
+28 28 | {k for k in obj.keys()}  # SIM118
 29 29 | 
 
-SIM118.py:28:11: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
+SIM118.py:28:8: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
    |
-26 | {k for k in obj.keys()}  # SIM118
+26 | [k for k in obj.keys()]  # SIM118
 27 | 
-28 | {k: k for k in obj.keys()}  # SIM118
+28 | {k for k in obj.keys()}  # SIM118
+   |        ^^^^^^^^^^^^^^^ SIM118
+29 | 
+30 | {k: k for k in obj.keys()}  # SIM118
+   |
+   = help: Remove `.keys()`
+
+ℹ Suggested fix
+25 25 | 
+26 26 | [k for k in obj.keys()]  # SIM118
+27 27 | 
+28    |-{k for k in obj.keys()}  # SIM118
+   28 |+{k for k in obj}  # SIM118
+29 29 | 
+30 30 | {k: k for k in obj.keys()}  # SIM118
+31 31 | 
+
+SIM118.py:30:11: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
+   |
+28 | {k for k in obj.keys()}  # SIM118
+29 | 
+30 | {k: k for k in obj.keys()}  # SIM118
    |           ^^^^^^^^^^^^^^^ SIM118
-29 | 
-30 | (k for k in obj.keys())  # SIM118
+31 | 
+32 | (k for k in obj.keys())  # SIM118
    |
    = help: Remove `.keys()`
 
 ℹ Suggested fix
-25 25 | 
-26 26 | {k for k in obj.keys()}  # SIM118
 27 27 | 
-28    |-{k: k for k in obj.keys()}  # SIM118
-   28 |+{k: k for k in obj}  # SIM118
+28 28 | {k for k in obj.keys()}  # SIM118
 29 29 | 
-30 30 | (k for k in obj.keys())  # SIM118
+30    |-{k: k for k in obj.keys()}  # SIM118
+   30 |+{k: k for k in obj}  # SIM118
 31 31 | 
+32 32 | (k for k in obj.keys())  # SIM118
+33 33 | 
 
-SIM118.py:30:8: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
+SIM118.py:32:8: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
    |
-28 | {k: k for k in obj.keys()}  # SIM118
-29 | 
-30 | (k for k in obj.keys())  # SIM118
+30 | {k: k for k in obj.keys()}  # SIM118
+31 | 
+32 | (k for k in obj.keys())  # SIM118
    |        ^^^^^^^^^^^^^^^ SIM118
-31 | 
-32 | key in (obj or {}).keys()  # SIM118
-   |
-   = help: Remove `.keys()`
-
-ℹ Suggested fix
-27 27 | 
-28 28 | {k: k for k in obj.keys()}  # SIM118
-29 29 | 
-30    |-(k for k in obj.keys())  # SIM118
-   30 |+(k for k in obj)  # SIM118
-31 31 | 
-32 32 | key in (obj or {}).keys()  # SIM118
-33 33 | 
-
-SIM118.py:32:1: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
-   |
-30 | (k for k in obj.keys())  # SIM118
-31 | 
-32 | key in (obj or {}).keys()  # SIM118
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^ SIM118
 33 | 
-34 | (key) in (obj or {}).keys()  # SIM118
+34 | key in (obj or {}).keys()  # SIM118
    |
    = help: Remove `.keys()`
 
 ℹ Suggested fix
 29 29 | 
-30 30 | (k for k in obj.keys())  # SIM118
+30 30 | {k: k for k in obj.keys()}  # SIM118
 31 31 | 
-32    |-key in (obj or {}).keys()  # SIM118
-   32 |+key in (obj or {})  # SIM118
+32    |-(k for k in obj.keys())  # SIM118
+   32 |+(k for k in obj)  # SIM118
 33 33 | 
-34 34 | (key) in (obj or {}).keys()  # SIM118
+34 34 | key in (obj or {}).keys()  # SIM118
 35 35 | 
 
 SIM118.py:34:1: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
    |
-32 | key in (obj or {}).keys()  # SIM118
+32 | (k for k in obj.keys())  # SIM118
 33 | 
-34 | (key) in (obj or {}).keys()  # SIM118
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ SIM118
+34 | key in (obj or {}).keys()  # SIM118
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^ SIM118
 35 | 
-36 | from typing import KeysView
+36 | (key) in (obj or {}).keys()  # SIM118
    |
    = help: Remove `.keys()`
 
 ℹ Suggested fix
 31 31 | 
-32 32 | key in (obj or {}).keys()  # SIM118
+32 32 | (k for k in obj.keys())  # SIM118
 33 33 | 
-34    |-(key) in (obj or {}).keys()  # SIM118
-   34 |+(key) in (obj or {})  # SIM118
+34    |-key in (obj or {}).keys()  # SIM118
+   34 |+key in (obj or {})  # SIM118
 35 35 | 
-36 36 | from typing import KeysView
+36 36 | (key) in (obj or {}).keys()  # SIM118
 37 37 | 
 
-SIM118.py:48:1: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
+SIM118.py:36:1: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
    |
-47 | # Regression test for: https://github.com/astral-sh/ruff/issues/7124
-48 | key in obj.keys()and foo
-   | ^^^^^^^^^^^^^^^^^ SIM118
-49 | (key in obj.keys())and foo
-50 | key in (obj.keys())and foo
+34 | key in (obj or {}).keys()  # SIM118
+35 | 
+36 | (key) in (obj or {}).keys()  # SIM118
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ SIM118
+37 | 
+38 | from typing import KeysView
    |
    = help: Remove `.keys()`
 
 ℹ Suggested fix
-45 45 | 
-46 46 | 
-47 47 | # Regression test for: https://github.com/astral-sh/ruff/issues/7124
-48    |-key in obj.keys()and foo
-   48 |+key in obj and foo
-49 49 | (key in obj.keys())and foo
-50 50 | key in (obj.keys())and foo
-51 51 | 
-
-SIM118.py:49:2: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
-   |
-47 | # Regression test for: https://github.com/astral-sh/ruff/issues/7124
-48 | key in obj.keys()and foo
-49 | (key in obj.keys())and foo
-   |  ^^^^^^^^^^^^^^^^^ SIM118
-50 | key in (obj.keys())and foo
-   |
-   = help: Remove `.keys()`
-
-ℹ Suggested fix
-46 46 | 
-47 47 | # Regression test for: https://github.com/astral-sh/ruff/issues/7124
-48 48 | key in obj.keys()and foo
-49    |-(key in obj.keys())and foo
-   49 |+(key in obj)and foo
-50 50 | key in (obj.keys())and foo
-51 51 | 
-52 52 | # Regression test for: https://github.com/astral-sh/ruff/issues/7200
+33 33 | 
+34 34 | key in (obj or {}).keys()  # SIM118
+35 35 | 
+36    |-(key) in (obj or {}).keys()  # SIM118
+   36 |+(key) in (obj or {})  # SIM118
+37 37 | 
+38 38 | from typing import KeysView
+39 39 | 
 
 SIM118.py:50:1: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
    |
-48 | key in obj.keys()and foo
-49 | (key in obj.keys())and foo
-50 | key in (obj.keys())and foo
+49 | # Regression test for: https://github.com/astral-sh/ruff/issues/7124
+50 | key in obj.keys()and foo
+   | ^^^^^^^^^^^^^^^^^ SIM118
+51 | (key in obj.keys())and foo
+52 | key in (obj.keys())and foo
+   |
+   = help: Remove `.keys()`
+
+ℹ Suggested fix
+47 47 | 
+48 48 | 
+49 49 | # Regression test for: https://github.com/astral-sh/ruff/issues/7124
+50    |-key in obj.keys()and foo
+   50 |+key in obj and foo
+51 51 | (key in obj.keys())and foo
+52 52 | key in (obj.keys())and foo
+53 53 | 
+
+SIM118.py:51:2: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
+   |
+49 | # Regression test for: https://github.com/astral-sh/ruff/issues/7124
+50 | key in obj.keys()and foo
+51 | (key in obj.keys())and foo
+   |  ^^^^^^^^^^^^^^^^^ SIM118
+52 | key in (obj.keys())and foo
+   |
+   = help: Remove `.keys()`
+
+ℹ Suggested fix
+48 48 | 
+49 49 | # Regression test for: https://github.com/astral-sh/ruff/issues/7124
+50 50 | key in obj.keys()and foo
+51    |-(key in obj.keys())and foo
+   51 |+(key in obj)and foo
+52 52 | key in (obj.keys())and foo
+53 53 | 
+54 54 | # Regression test for: https://github.com/astral-sh/ruff/issues/7200
+
+SIM118.py:52:1: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
+   |
+50 | key in obj.keys()and foo
+51 | (key in obj.keys())and foo
+52 | key in (obj.keys())and foo
    | ^^^^^^^^^^^^^^^^^^^ SIM118
-51 | 
-52 | # Regression test for: https://github.com/astral-sh/ruff/issues/7200
+53 | 
+54 | # Regression test for: https://github.com/astral-sh/ruff/issues/7200
    |
    = help: Remove `.keys()`
 
 ℹ Suggested fix
-47 47 | # Regression test for: https://github.com/astral-sh/ruff/issues/7124
-48 48 | key in obj.keys()and foo
-49 49 | (key in obj.keys())and foo
-50    |-key in (obj.keys())and foo
-   50 |+key in (obj)and foo
-51 51 | 
-52 52 | # Regression test for: https://github.com/astral-sh/ruff/issues/7200
-53 53 | for key in (
+49 49 | # Regression test for: https://github.com/astral-sh/ruff/issues/7124
+50 50 | key in obj.keys()and foo
+51 51 | (key in obj.keys())and foo
+52    |-key in (obj.keys())and foo
+   52 |+key in (obj)and foo
+53 53 | 
+54 54 | # Regression test for: https://github.com/astral-sh/ruff/issues/7200
+55 55 | for key in (
 
-SIM118.py:53:5: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
+SIM118.py:55:5: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
    |
-52 |   # Regression test for: https://github.com/astral-sh/ruff/issues/7200
-53 |   for key in (
+54 |   # Regression test for: https://github.com/astral-sh/ruff/issues/7200
+55 |   for key in (
    |  _____^
-54 | |     self.experiment.surveys[0]
-55 | |         .stations[0]
-56 | |         .keys()
-57 | | ):
+56 | |     self.experiment.surveys[0]
+57 | |         .stations[0]
+58 | |         .keys()
+59 | | ):
    | |_^ SIM118
-58 |       continue
+60 |       continue
    |
    = help: Remove `.keys()`
 
 ℹ Suggested fix
-53 53 | for key in (
-54 54 |     self.experiment.surveys[0]
-55 55 |         .stations[0]
-56    |-        .keys()
-   56 |+        
-57 57 | ):
-58 58 |     continue
+55 55 | for key in (
+56 56 |     self.experiment.surveys[0]
+57 57 |         .stations[0]
+58    |-        .keys()
+   58 |+        
+59 59 | ):
+60 60 |     continue
 
 

crates/ruff_linter/src/rules/flake8_simplify/snapshots/ruff_linter__rules__flake8_simplify__tests__preview__SIM118_SIM118.py.snap

@@ -0,0 +1,401 @@
+---
+source: crates/ruff_linter/src/rules/flake8_simplify/mod.rs
+---
+SIM118.py:3:1: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
+  |
+1 | obj = {}
+2 | 
+3 | key in obj.keys()  # SIM118
+  | ^^^^^^^^^^^^^^^^^ SIM118
+4 | 
+5 | key not in obj.keys()  # SIM118
+  |
+  = help: Remove `.keys()`
+
+ℹ Fix
+1 1 | obj = {}
+2 2 | 
+3   |-key in obj.keys()  # SIM118
+  3 |+key in obj  # SIM118
+4 4 | 
+5 5 | key not in obj.keys()  # SIM118
+6 6 | 
+
+SIM118.py:5:1: SIM118 [*] Use `key not in dict` instead of `key not in dict.keys()`
+  |
+3 | key in obj.keys()  # SIM118
+4 | 
+5 | key not in obj.keys()  # SIM118
+  | ^^^^^^^^^^^^^^^^^^^^^ SIM118
+6 | 
+7 | foo["bar"] in obj.keys()  # SIM118
+  |
+  = help: Remove `.keys()`
+
+ℹ Fix
+2 2 | 
+3 3 | key in obj.keys()  # SIM118
+4 4 | 
+5   |-key not in obj.keys()  # SIM118
+  5 |+key not in obj  # SIM118
+6 6 | 
+7 7 | foo["bar"] in obj.keys()  # SIM118
+8 8 | 
+
+SIM118.py:7:1: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
+  |
+5 | key not in obj.keys()  # SIM118
+6 | 
+7 | foo["bar"] in obj.keys()  # SIM118
+  | ^^^^^^^^^^^^^^^^^^^^^^^^ SIM118
+8 | 
+9 | foo["bar"] not in obj.keys()  # SIM118
+  |
+  = help: Remove `.keys()`
+
+ℹ Fix
+4 4 | 
+5 5 | key not in obj.keys()  # SIM118
+6 6 | 
+7   |-foo["bar"] in obj.keys()  # SIM118
+  7 |+foo["bar"] in obj  # SIM118
+8 8 | 
+9 9 | foo["bar"] not in obj.keys()  # SIM118
+10 10 | 
+
+SIM118.py:9:1: SIM118 [*] Use `key not in dict` instead of `key not in dict.keys()`
+   |
+ 7 | foo["bar"] in obj.keys()  # SIM118
+ 8 | 
+ 9 | foo["bar"] not in obj.keys()  # SIM118
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ SIM118
+10 | 
+11 | foo['bar'] in obj.keys()  # SIM118
+   |
+   = help: Remove `.keys()`
+
+ℹ Fix
+6  6  | 
+7  7  | foo["bar"] in obj.keys()  # SIM118
+8  8  | 
+9     |-foo["bar"] not in obj.keys()  # SIM118
+   9  |+foo["bar"] not in obj  # SIM118
+10 10 | 
+11 11 | foo['bar'] in obj.keys()  # SIM118
+12 12 | 
+
+SIM118.py:11:1: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
+   |
+ 9 | foo["bar"] not in obj.keys()  # SIM118
+10 | 
+11 | foo['bar'] in obj.keys()  # SIM118
+   | ^^^^^^^^^^^^^^^^^^^^^^^^ SIM118
+12 | 
+13 | foo['bar'] not in obj.keys()  # SIM118
+   |
+   = help: Remove `.keys()`
+
+ℹ Fix
+8  8  | 
+9  9  | foo["bar"] not in obj.keys()  # SIM118
+10 10 | 
+11    |-foo['bar'] in obj.keys()  # SIM118
+   11 |+foo['bar'] in obj  # SIM118
+12 12 | 
+13 13 | foo['bar'] not in obj.keys()  # SIM118
+14 14 | 
+
+SIM118.py:13:1: SIM118 [*] Use `key not in dict` instead of `key not in dict.keys()`
+   |
+11 | foo['bar'] in obj.keys()  # SIM118
+12 | 
+13 | foo['bar'] not in obj.keys()  # SIM118
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ SIM118
+14 | 
+15 | foo() in obj.keys()  # SIM118
+   |
+   = help: Remove `.keys()`
+
+ℹ Fix
+10 10 | 
+11 11 | foo['bar'] in obj.keys()  # SIM118
+12 12 | 
+13    |-foo['bar'] not in obj.keys()  # SIM118
+   13 |+foo['bar'] not in obj  # SIM118
+14 14 | 
+15 15 | foo() in obj.keys()  # SIM118
+16 16 | 
+
+SIM118.py:15:1: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
+   |
+13 | foo['bar'] not in obj.keys()  # SIM118
+14 | 
+15 | foo() in obj.keys()  # SIM118
+   | ^^^^^^^^^^^^^^^^^^^ SIM118
+16 | 
+17 | foo() not in obj.keys()  # SIM118
+   |
+   = help: Remove `.keys()`
+
+ℹ Fix
+12 12 | 
+13 13 | foo['bar'] not in obj.keys()  # SIM118
+14 14 | 
+15    |-foo() in obj.keys()  # SIM118
+   15 |+foo() in obj  # SIM118
+16 16 | 
+17 17 | foo() not in obj.keys()  # SIM118
+18 18 | 
+
+SIM118.py:17:1: SIM118 [*] Use `key not in dict` instead of `key not in dict.keys()`
+   |
+15 | foo() in obj.keys()  # SIM118
+16 | 
+17 | foo() not in obj.keys()  # SIM118
+   | ^^^^^^^^^^^^^^^^^^^^^^^ SIM118
+18 | 
+19 | for key in obj.keys():  # SIM118
+   |
+   = help: Remove `.keys()`
+
+ℹ Fix
+14 14 | 
+15 15 | foo() in obj.keys()  # SIM118
+16 16 | 
+17    |-foo() not in obj.keys()  # SIM118
+   17 |+foo() not in obj  # SIM118
+18 18 | 
+19 19 | for key in obj.keys():  # SIM118
+20 20 |     pass
+
+SIM118.py:19:5: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
+   |
+17 | foo() not in obj.keys()  # SIM118
+18 | 
+19 | for key in obj.keys():  # SIM118
+   |     ^^^^^^^^^^^^^^^^^ SIM118
+20 |     pass
+   |
+   = help: Remove `.keys()`
+
+ℹ Fix
+16 16 | 
+17 17 | foo() not in obj.keys()  # SIM118
+18 18 | 
+19    |-for key in obj.keys():  # SIM118
+   19 |+for key in obj:  # SIM118
+20 20 |     pass
+21 21 | 
+22 22 | for key in list(obj.keys()):
+
+SIM118.py:26:8: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
+   |
+24 |         del obj[key]
+25 | 
+26 | [k for k in obj.keys()]  # SIM118
+   |        ^^^^^^^^^^^^^^^ SIM118
+27 | 
+28 | {k for k in obj.keys()}  # SIM118
+   |
+   = help: Remove `.keys()`
+
+ℹ Fix
+23 23 |     if some_property(key):
+24 24 |         del obj[key]
+25 25 | 
+26    |-[k for k in obj.keys()]  # SIM118
+   26 |+[k for k in obj]  # SIM118
+27 27 | 
+28 28 | {k for k in obj.keys()}  # SIM118
+29 29 | 
+
+SIM118.py:28:8: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
+   |
+26 | [k for k in obj.keys()]  # SIM118
+27 | 
+28 | {k for k in obj.keys()}  # SIM118
+   |        ^^^^^^^^^^^^^^^ SIM118
+29 | 
+30 | {k: k for k in obj.keys()}  # SIM118
+   |
+   = help: Remove `.keys()`
+
+ℹ Fix
+25 25 | 
+26 26 | [k for k in obj.keys()]  # SIM118
+27 27 | 
+28    |-{k for k in obj.keys()}  # SIM118
+   28 |+{k for k in obj}  # SIM118
+29 29 | 
+30 30 | {k: k for k in obj.keys()}  # SIM118
+31 31 | 
+
+SIM118.py:30:11: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
+   |
+28 | {k for k in obj.keys()}  # SIM118
+29 | 
+30 | {k: k for k in obj.keys()}  # SIM118
+   |           ^^^^^^^^^^^^^^^ SIM118
+31 | 
+32 | (k for k in obj.keys())  # SIM118
+   |
+   = help: Remove `.keys()`
+
+ℹ Fix
+27 27 | 
+28 28 | {k for k in obj.keys()}  # SIM118
+29 29 | 
+30    |-{k: k for k in obj.keys()}  # SIM118
+   30 |+{k: k for k in obj}  # SIM118
+31 31 | 
+32 32 | (k for k in obj.keys())  # SIM118
+33 33 | 
+
+SIM118.py:32:8: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
+   |
+30 | {k: k for k in obj.keys()}  # SIM118
+31 | 
+32 | (k for k in obj.keys())  # SIM118
+   |        ^^^^^^^^^^^^^^^ SIM118
+33 | 
+34 | key in (obj or {}).keys()  # SIM118
+   |
+   = help: Remove `.keys()`
+
+ℹ Fix
+29 29 | 
+30 30 | {k: k for k in obj.keys()}  # SIM118
+31 31 | 
+32    |-(k for k in obj.keys())  # SIM118
+   32 |+(k for k in obj)  # SIM118
+33 33 | 
+34 34 | key in (obj or {}).keys()  # SIM118
+35 35 | 
+
+SIM118.py:34:1: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
+   |
+32 | (k for k in obj.keys())  # SIM118
+33 | 
+34 | key in (obj or {}).keys()  # SIM118
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^ SIM118
+35 | 
+36 | (key) in (obj or {}).keys()  # SIM118
+   |
+   = help: Remove `.keys()`
+
+ℹ Suggested fix
+31 31 | 
+32 32 | (k for k in obj.keys())  # SIM118
+33 33 | 
+34    |-key in (obj or {}).keys()  # SIM118
+   34 |+key in (obj or {})  # SIM118
+35 35 | 
+36 36 | (key) in (obj or {}).keys()  # SIM118
+37 37 | 
+
+SIM118.py:36:1: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
+   |
+34 | key in (obj or {}).keys()  # SIM118
+35 | 
+36 | (key) in (obj or {}).keys()  # SIM118
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ SIM118
+37 | 
+38 | from typing import KeysView
+   |
+   = help: Remove `.keys()`
+
+ℹ Suggested fix
+33 33 | 
+34 34 | key in (obj or {}).keys()  # SIM118
+35 35 | 
+36    |-(key) in (obj or {}).keys()  # SIM118
+   36 |+(key) in (obj or {})  # SIM118
+37 37 | 
+38 38 | from typing import KeysView
+39 39 | 
+
+SIM118.py:50:1: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
+   |
+49 | # Regression test for: https://github.com/astral-sh/ruff/issues/7124
+50 | key in obj.keys()and foo
+   | ^^^^^^^^^^^^^^^^^ SIM118
+51 | (key in obj.keys())and foo
+52 | key in (obj.keys())and foo
+   |
+   = help: Remove `.keys()`
+
+ℹ Fix
+47 47 | 
+48 48 | 
+49 49 | # Regression test for: https://github.com/astral-sh/ruff/issues/7124
+50    |-key in obj.keys()and foo
+   50 |+key in obj and foo
+51 51 | (key in obj.keys())and foo
+52 52 | key in (obj.keys())and foo
+53 53 | 
+
+SIM118.py:51:2: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
+   |
+49 | # Regression test for: https://github.com/astral-sh/ruff/issues/7124
+50 | key in obj.keys()and foo
+51 | (key in obj.keys())and foo
+   |  ^^^^^^^^^^^^^^^^^ SIM118
+52 | key in (obj.keys())and foo
+   |
+   = help: Remove `.keys()`
+
+ℹ Fix
+48 48 | 
+49 49 | # Regression test for: https://github.com/astral-sh/ruff/issues/7124
+50 50 | key in obj.keys()and foo
+51    |-(key in obj.keys())and foo
+   51 |+(key in obj)and foo
+52 52 | key in (obj.keys())and foo
+53 53 | 
+54 54 | # Regression test for: https://github.com/astral-sh/ruff/issues/7200
+
+SIM118.py:52:1: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
+   |
+50 | key in obj.keys()and foo
+51 | (key in obj.keys())and foo
+52 | key in (obj.keys())and foo
+   | ^^^^^^^^^^^^^^^^^^^ SIM118
+53 | 
+54 | # Regression test for: https://github.com/astral-sh/ruff/issues/7200
+   |
+   = help: Remove `.keys()`
+
+ℹ Fix
+49 49 | # Regression test for: https://github.com/astral-sh/ruff/issues/7124
+50 50 | key in obj.keys()and foo
+51 51 | (key in obj.keys())and foo
+52    |-key in (obj.keys())and foo
+   52 |+key in (obj)and foo
+53 53 | 
+54 54 | # Regression test for: https://github.com/astral-sh/ruff/issues/7200
+55 55 | for key in (
+
+SIM118.py:55:5: SIM118 [*] Use `key in dict` instead of `key in dict.keys()`
+   |
+54 |   # Regression test for: https://github.com/astral-sh/ruff/issues/7200
+55 |   for key in (
+   |  _____^
+56 | |     self.experiment.surveys[0]
+57 | |         .stations[0]
+58 | |         .keys()
+59 | | ):
+   | |_^ SIM118
+60 |       continue
+   |
+   = help: Remove `.keys()`
+
+ℹ Suggested fix
+55 55 | for key in (
+56 56 |     self.experiment.surveys[0]
+57 57 |         .stations[0]
+58    |-        .keys()
+   58 |+        
+59 59 | ):
+60 60 |     continue
+
+

crates/ruff_linter/src/rules/flake8_trio/method_name.rs

@@ -0,0 +1,157 @@
+use ruff_python_ast::call_path::CallPath;
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+pub(super) enum MethodName {
+    AcloseForcefully,
+    CancelScope,
+    CancelShieldedCheckpoint,
+    Checkpoint,
+    CheckpointIfCancelled,
+    FailAfter,
+    FailAt,
+    MoveOnAfter,
+    MoveOnAt,
+    OpenFile,
+    OpenProcess,
+    OpenSslOverTcpListeners,
+    OpenSslOverTcpStream,
+    OpenTcpListeners,
+    OpenTcpStream,
+    OpenUnixSocket,
+    PermanentlyDetachCoroutineObject,
+    ReattachDetachedCoroutineObject,
+    RunProcess,
+    ServeListeners,
+    ServeSslOverTcp,
+    ServeTcp,
+    Sleep,
+    SleepForever,
+    TemporarilyDetachCoroutineObject,
+    WaitReadable,
+    WaitTaskRescheduled,
+    WaitWritable,
+}
+
+impl MethodName {
+    /// Returns `true` if the method is async, `false` if it is sync.
+    pub(super) fn is_async(self) -> bool {
+        match self {
+            MethodName::AcloseForcefully
+            | MethodName::CancelShieldedCheckpoint
+            | MethodName::Checkpoint
+            | MethodName::CheckpointIfCancelled
+            | MethodName::OpenFile
+            | MethodName::OpenProcess
+            | MethodName::OpenSslOverTcpListeners
+            | MethodName::OpenSslOverTcpStream
+            | MethodName::OpenTcpListeners
+            | MethodName::OpenTcpStream
+            | MethodName::OpenUnixSocket
+            | MethodName::PermanentlyDetachCoroutineObject
+            | MethodName::ReattachDetachedCoroutineObject
+            | MethodName::RunProcess
+            | MethodName::ServeListeners
+            | MethodName::ServeSslOverTcp
+            | MethodName::ServeTcp
+            | MethodName::Sleep
+            | MethodName::SleepForever
+            | MethodName::TemporarilyDetachCoroutineObject
+            | MethodName::WaitReadable
+            | MethodName::WaitTaskRescheduled
+            | MethodName::WaitWritable => true,
+
+            MethodName::MoveOnAfter
+            | MethodName::MoveOnAt
+            | MethodName::FailAfter
+            | MethodName::FailAt
+            | MethodName::CancelScope => false,
+        }
+    }
+}
+
+impl MethodName {
+    pub(super) fn try_from(call_path: &CallPath<'_>) -> Option<Self> {
+        match call_path.as_slice() {
+            ["trio", "CancelScope"] => Some(Self::CancelScope),
+            ["trio", "aclose_forcefully"] => Some(Self::AcloseForcefully),
+            ["trio", "fail_after"] => Some(Self::FailAfter),
+            ["trio", "fail_at"] => Some(Self::FailAt),
+            ["trio", "lowlevel", "cancel_shielded_checkpoint"] => {
+                Some(Self::CancelShieldedCheckpoint)
+            }
+            ["trio", "lowlevel", "checkpoint"] => Some(Self::Checkpoint),
+            ["trio", "lowlevel", "checkpoint_if_cancelled"] => Some(Self::CheckpointIfCancelled),
+            ["trio", "lowlevel", "open_process"] => Some(Self::OpenProcess),
+            ["trio", "lowlevel", "permanently_detach_coroutine_object"] => {
+                Some(Self::PermanentlyDetachCoroutineObject)
+            }
+            ["trio", "lowlevel", "reattach_detached_coroutine_object"] => {
+                Some(Self::ReattachDetachedCoroutineObject)
+            }
+            ["trio", "lowlevel", "temporarily_detach_coroutine_object"] => {
+                Some(Self::TemporarilyDetachCoroutineObject)
+            }
+            ["trio", "lowlevel", "wait_readable"] => Some(Self::WaitReadable),
+            ["trio", "lowlevel", "wait_task_rescheduled"] => Some(Self::WaitTaskRescheduled),
+            ["trio", "lowlevel", "wait_writable"] => Some(Self::WaitWritable),
+            ["trio", "move_on_after"] => Some(Self::MoveOnAfter),
+            ["trio", "move_on_at"] => Some(Self::MoveOnAt),
+            ["trio", "open_file"] => Some(Self::OpenFile),
+            ["trio", "open_ssl_over_tcp_listeners"] => Some(Self::OpenSslOverTcpListeners),
+            ["trio", "open_ssl_over_tcp_stream"] => Some(Self::OpenSslOverTcpStream),
+            ["trio", "open_tcp_listeners"] => Some(Self::OpenTcpListeners),
+            ["trio", "open_tcp_stream"] => Some(Self::OpenTcpStream),
+            ["trio", "open_unix_socket"] => Some(Self::OpenUnixSocket),
+            ["trio", "run_process"] => Some(Self::RunProcess),
+            ["trio", "serve_listeners"] => Some(Self::ServeListeners),
+            ["trio", "serve_ssl_over_tcp"] => Some(Self::ServeSslOverTcp),
+            ["trio", "serve_tcp"] => Some(Self::ServeTcp),
+            ["trio", "sleep"] => Some(Self::Sleep),
+            ["trio", "sleep_forever"] => Some(Self::SleepForever),
+            _ => None,
+        }
+    }
+}
+
+impl std::fmt::Display for MethodName {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            MethodName::AcloseForcefully => write!(f, "trio.aclose_forcefully"),
+            MethodName::CancelScope => write!(f, "trio.CancelScope"),
+            MethodName::CancelShieldedCheckpoint => {
+                write!(f, "trio.lowlevel.cancel_shielded_checkpoint")
+            }
+            MethodName::Checkpoint => write!(f, "trio.lowlevel.checkpoint"),
+            MethodName::CheckpointIfCancelled => write!(f, "trio.lowlevel.checkpoint_if_cancelled"),
+            MethodName::FailAfter => write!(f, "trio.fail_after"),
+            MethodName::FailAt => write!(f, "trio.fail_at"),
+            MethodName::MoveOnAfter => write!(f, "trio.move_on_after"),
+            MethodName::MoveOnAt => write!(f, "trio.move_on_at"),
+            MethodName::OpenFile => write!(f, "trio.open_file"),
+            MethodName::OpenProcess => write!(f, "trio.lowlevel.open_process"),
+            MethodName::OpenSslOverTcpListeners => write!(f, "trio.open_ssl_over_tcp_listeners"),
+            MethodName::OpenSslOverTcpStream => write!(f, "trio.open_ssl_over_tcp_stream"),
+            MethodName::OpenTcpListeners => write!(f, "trio.open_tcp_listeners"),
+            MethodName::OpenTcpStream => write!(f, "trio.open_tcp_stream"),
+            MethodName::OpenUnixSocket => write!(f, "trio.open_unix_socket"),
+            MethodName::PermanentlyDetachCoroutineObject => {
+                write!(f, "trio.lowlevel.permanently_detach_coroutine_object")
+            }
+            MethodName::ReattachDetachedCoroutineObject => {
+                write!(f, "trio.lowlevel.reattach_detached_coroutine_object")
+            }
+            MethodName::RunProcess => write!(f, "trio.run_process"),
+            MethodName::ServeListeners => write!(f, "trio.serve_listeners"),
+            MethodName::ServeSslOverTcp => write!(f, "trio.serve_ssl_over_tcp"),
+            MethodName::ServeTcp => write!(f, "trio.serve_tcp"),
+            MethodName::Sleep => write!(f, "trio.sleep"),
+            MethodName::SleepForever => write!(f, "trio.sleep_forever"),
+            MethodName::TemporarilyDetachCoroutineObject => {
+                write!(f, "trio.lowlevel.temporarily_detach_coroutine_object")
+            }
+            MethodName::WaitReadable => write!(f, "trio.lowlevel.wait_readable"),
+            MethodName::WaitTaskRescheduled => write!(f, "trio.lowlevel.wait_task_rescheduled"),
+            MethodName::WaitWritable => write!(f, "trio.lowlevel.wait_writable"),
+        }
+    }
+}

crates/ruff_linter/src/rules/flake8_trio/mod.rs

@@ -1,4 +1,5 @@
 //! Rules from [flake8-trio](https://pypi.org/project/flake8-trio/).
+pub(super) mod method_name;
 pub(crate) mod rules;
 
 #[cfg(test)]
@@ -14,6 +15,8 @@ mod tests {
     use crate::test::test_path;
 
     #[test_case(Rule::TrioTimeoutWithoutAwait, Path::new("TRIO100.py"))]
+    #[test_case(Rule::TrioSyncCall, Path::new("TRIO105.py"))]
+    #[test_case(Rule::TrioZeroSleepCall, Path::new("TRIO115.py"))]
     fn rules(rule_code: Rule, path: &Path) -> Result<()> {
         let snapshot = format!("{}_{}", rule_code.noqa_code(), path.to_string_lossy());
         let diagnostics = test_path(

crates/ruff_linter/src/rules/flake8_trio/rules/mod.rs

@@ -1,3 +1,7 @@
+pub(crate) use sync_call::*;
 pub(crate) use timeout_without_await::*;
+pub(crate) use zero_sleep_call::*;
 
+mod sync_call;
 mod timeout_without_await;
+mod zero_sleep_call;

crates/ruff_linter/src/rules/flake8_trio/rules/sync_call.rs

@@ -0,0 +1,87 @@
+use ruff_diagnostics::{Diagnostic, Edit, Fix, FixAvailability, Violation};
+use ruff_macros::{derive_message_formats, violation};
+use ruff_python_ast::{Expr, ExprCall};
+use ruff_text_size::{Ranged, TextRange};
+
+use crate::checkers::ast::Checker;
+use crate::fix::edits::pad;
+use crate::rules::flake8_trio::method_name::MethodName;
+
+/// ## What it does
+/// Checks for calls to trio functions that are not immediately awaited.
+///
+/// ## Why is this bad?
+/// Many of the functions exposed by trio are asynchronous, and must be awaited
+/// to take effect. Calling a trio function without an `await` can lead to
+/// `RuntimeWarning` diagnostics and unexpected behaviour.
+///
+/// ## Example
+/// ```python
+/// async def double_sleep(x):
+///     trio.sleep(2 * x)
+/// ```
+///
+/// Use instead:
+/// ```python
+/// async def double_sleep(x):
+///     await trio.sleep(2 * x)
+/// ```
+///
+/// ## Fix safety
+/// This rule's fix is marked as unsafe, as adding an `await` to a function
+/// call changes its semantics and runtime behavior.
+#[violation]
+pub struct TrioSyncCall {
+    method_name: MethodName,
+}
+
+impl Violation for TrioSyncCall {
+    const FIX_AVAILABILITY: FixAvailability = FixAvailability::Sometimes;
+
+    #[derive_message_formats]
+    fn message(&self) -> String {
+        let Self { method_name } = self;
+        format!("Call to `{method_name}` is not immediately awaited")
+    }
+
+    fn fix_title(&self) -> Option<String> {
+        Some(format!("Add `await`"))
+    }
+}
+
+/// TRIO105
+pub(crate) fn sync_call(checker: &mut Checker, call: &ExprCall) {
+    let Some(method_name) = ({
+        let Some(call_path) = checker.semantic().resolve_call_path(call.func.as_ref()) else {
+            return;
+        };
+        MethodName::try_from(&call_path)
+    }) else {
+        return;
+    };
+
+    if !method_name.is_async() {
+        return;
+    }
+
+    if checker
+        .semantic()
+        .current_expression_parent()
+        .is_some_and(Expr::is_await_expr)
+    {
+        return;
+    };
+
+    let mut diagnostic = Diagnostic::new(TrioSyncCall { method_name }, call.range);
+    if checker.semantic().in_async_context() {
+        diagnostic.set_fix(Fix::unsafe_edit(Edit::insertion(
+            pad(
+                "await".to_string(),
+                TextRange::new(call.func.start(), call.func.start()),
+                checker.locator(),
+            ),
+            call.func.start(),
+        )));
+    }
+    checker.diagnostics.push(diagnostic);
+}

crates/ruff_linter/src/rules/flake8_trio/rules/timeout_without_await.rs

@@ -1,10 +1,11 @@
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
-use ruff_python_ast::call_path::CallPath;
-use ruff_python_ast::visitor::{walk_expr, walk_stmt, Visitor};
-use ruff_python_ast::{Expr, ExprAwait, Stmt, StmtWith, WithItem};
+use ruff_python_ast::helpers::AwaitVisitor;
+use ruff_python_ast::visitor::Visitor;
+use ruff_python_ast::{StmtWith, WithItem};
 
 use crate::checkers::ast::Checker;
+use crate::rules::flake8_trio::method_name::MethodName;
 
 /// ## What it does
 /// Checks for trio functions that should contain await but don't.
@@ -56,6 +57,17 @@ pub(crate) fn timeout_without_await(
         return;
     };
 
+    if !matches!(
+        method_name,
+        MethodName::MoveOnAfter
+            | MethodName::MoveOnAt
+            | MethodName::FailAfter
+            | MethodName::FailAt
+            | MethodName::CancelScope
+    ) {
+        return;
+    }
+
     let mut visitor = AwaitVisitor::default();
     visitor.visit_body(&with_stmt.body);
     if visitor.seen_await {
@@ -67,59 +79,3 @@ pub(crate) fn timeout_without_await(
         with_stmt.range,
     ));
 }
-
-#[derive(Debug, Copy, Clone, PartialEq, Eq)]
-enum MethodName {
-    MoveOnAfter,
-    MoveOnAt,
-    FailAfter,
-    FailAt,
-    CancelScope,
-}
-
-impl MethodName {
-    fn try_from(call_path: &CallPath<'_>) -> Option<Self> {
-        match call_path.as_slice() {
-            ["trio", "move_on_after"] => Some(Self::MoveOnAfter),
-            ["trio", "move_on_at"] => Some(Self::MoveOnAt),
-            ["trio", "fail_after"] => Some(Self::FailAfter),
-            ["trio", "fail_at"] => Some(Self::FailAt),
-            ["trio", "CancelScope"] => Some(Self::CancelScope),
-            _ => None,
-        }
-    }
-}
-
-impl std::fmt::Display for MethodName {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        match self {
-            MethodName::MoveOnAfter => write!(f, "trio.move_on_after"),
-            MethodName::MoveOnAt => write!(f, "trio.move_on_at"),
-            MethodName::FailAfter => write!(f, "trio.fail_after"),
-            MethodName::FailAt => write!(f, "trio.fail_at"),
-            MethodName::CancelScope => write!(f, "trio.CancelScope"),
-        }
-    }
-}
-
-#[derive(Debug, Default)]
-struct AwaitVisitor {
-    seen_await: bool,
-}
-
-impl Visitor<'_> for AwaitVisitor {
-    fn visit_stmt(&mut self, stmt: &Stmt) {
-        match stmt {
-            Stmt::FunctionDef(_) | Stmt::ClassDef(_) => (),
-            _ => walk_stmt(self, stmt),
-        }
-    }
-
-    fn visit_expr(&mut self, expr: &Expr) {
-        if let Expr::Await(ExprAwait { .. }) = expr {
-            self.seen_await = true;
-        } else {
-            walk_expr(self, expr);
-        }
-    }
-}

crates/ruff_linter/src/rules/flake8_trio/rules/zero_sleep_call.rs

@@ -0,0 +1,109 @@
+use ruff_diagnostics::{AlwaysFixableViolation, Diagnostic, Edit, Fix};
+use ruff_macros::{derive_message_formats, violation};
+use ruff_python_ast::Stmt;
+use ruff_python_ast::{self as ast, Expr, ExprCall, Int};
+use ruff_text_size::Ranged;
+
+use crate::checkers::ast::Checker;
+use crate::importer::ImportRequest;
+
+/// ## What it does
+/// Checks for uses of `trio.sleep(0)`.
+///
+/// ## Why is this bad?
+/// `trio.sleep(0)` is equivalent to calling `trio.lowlevel.checkpoint()`.
+/// However, the latter better conveys the intent of the code.
+///
+/// ## Example
+/// ```python
+/// async def func():
+///     await trio.sleep(0)
+/// ```
+///
+/// Use instead:
+/// ```python
+/// async def func():
+///     await trio.lowlevel.checkpoint()
+/// ```
+#[violation]
+pub struct TrioZeroSleepCall;
+
+impl AlwaysFixableViolation for TrioZeroSleepCall {
+    #[derive_message_formats]
+    fn message(&self) -> String {
+        format!("Use `trio.lowlevel.checkpoint()` instead of `trio.sleep(0)`")
+    }
+
+    fn fix_title(&self) -> String {
+        format!("Replace with `trio.lowlevel.checkpoint()`")
+    }
+}
+
+/// TRIO115
+pub(crate) fn zero_sleep_call(checker: &mut Checker, call: &ExprCall) {
+    if !checker
+        .semantic()
+        .resolve_call_path(call.func.as_ref())
+        .is_some_and(|call_path| matches!(call_path.as_slice(), ["trio", "sleep"]))
+    {
+        return;
+    }
+
+    if call.arguments.len() != 1 {
+        return;
+    }
+
+    let Some(arg) = call.arguments.find_argument("seconds", 0) else {
+        return;
+    };
+
+    match arg {
+        Expr::NumberLiteral(ast::ExprNumberLiteral { value, .. }) => {
+            let Some(int) = value.as_int() else { return };
+            if *int != Int::ZERO {
+                return;
+            }
+        }
+        Expr::Name(ast::ExprName { id, .. }) => {
+            let scope = checker.semantic().current_scope();
+            if let Some(binding_id) = scope.get(id) {
+                let binding = checker.semantic().binding(binding_id);
+                if binding.kind.is_assignment() || binding.kind.is_named_expr_assignment() {
+                    if let Some(parent_id) = binding.source {
+                        let parent = checker.semantic().statement(parent_id);
+                        if let Stmt::Assign(ast::StmtAssign { value, .. })
+                        | Stmt::AnnAssign(ast::StmtAnnAssign {
+                            value: Some(value), ..
+                        })
+                        | Stmt::AugAssign(ast::StmtAugAssign { value, .. }) = parent
+                        {
+                            let Expr::NumberLiteral(ast::ExprNumberLiteral { value: num, .. }) =
+                                value.as_ref()
+                            else {
+                                return;
+                            };
+                            let Some(int) = num.as_int() else { return };
+                            if *int != Int::ZERO {
+                                return;
+                            }
+                        }
+                    }
+                }
+            }
+        }
+        _ => return,
+    }
+
+    let mut diagnostic = Diagnostic::new(TrioZeroSleepCall, call.range());
+    diagnostic.try_set_fix(|| {
+        let (import_edit, binding) = checker.importer().get_or_import_symbol(
+            &ImportRequest::import("trio", "lowlevel.checkpoint"),
+            call.func.start(),
+            checker.semantic(),
+        )?;
+        let reference_edit = Edit::range_replacement(binding, call.func.range());
+        let arg_edit = Edit::range_deletion(call.arguments.range);
+        Ok(Fix::safe_edits(import_edit, [reference_edit, arg_edit]))
+    });
+    checker.diagnostics.push(diagnostic);
+}

crates/ruff_linter/src/rules/flake8_trio/snapshots/ruff_linter__rules__flake8_trio__tests__TRIO105_TRIO105.py.snap

@@ -0,0 +1,514 @@
+---
+source: crates/ruff_linter/src/rules/flake8_trio/mod.rs
+---
+TRIO105.py:30:5: TRIO105 [*] Call to `trio.aclose_forcefully` is not immediately awaited
+   |
+29 |     # TRIO105
+30 |     trio.aclose_forcefully(foo)
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^ TRIO105
+31 |     trio.open_file(foo)
+32 |     trio.open_ssl_over_tcp_listeners(foo, foo)
+   |
+   = help: Add `await`
+
+ℹ Suggested fix
+27 27 |     await trio.lowlevel.wait_writable(foo)
+28 28 | 
+29 29 |     # TRIO105
+30    |-    trio.aclose_forcefully(foo)
+   30 |+    await trio.aclose_forcefully(foo)
+31 31 |     trio.open_file(foo)
+32 32 |     trio.open_ssl_over_tcp_listeners(foo, foo)
+33 33 |     trio.open_ssl_over_tcp_stream(foo, foo)
+
+TRIO105.py:31:5: TRIO105 [*] Call to `trio.open_file` is not immediately awaited
+   |
+29 |     # TRIO105
+30 |     trio.aclose_forcefully(foo)
+31 |     trio.open_file(foo)
+   |     ^^^^^^^^^^^^^^^^^^^ TRIO105
+32 |     trio.open_ssl_over_tcp_listeners(foo, foo)
+33 |     trio.open_ssl_over_tcp_stream(foo, foo)
+   |
+   = help: Add `await`
+
+ℹ Suggested fix
+28 28 | 
+29 29 |     # TRIO105
+30 30 |     trio.aclose_forcefully(foo)
+31    |-    trio.open_file(foo)
+   31 |+    await trio.open_file(foo)
+32 32 |     trio.open_ssl_over_tcp_listeners(foo, foo)
+33 33 |     trio.open_ssl_over_tcp_stream(foo, foo)
+34 34 |     trio.open_tcp_listeners(foo)
+
+TRIO105.py:32:5: TRIO105 [*] Call to `trio.open_ssl_over_tcp_listeners` is not immediately awaited
+   |
+30 |     trio.aclose_forcefully(foo)
+31 |     trio.open_file(foo)
+32 |     trio.open_ssl_over_tcp_listeners(foo, foo)
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ TRIO105
+33 |     trio.open_ssl_over_tcp_stream(foo, foo)
+34 |     trio.open_tcp_listeners(foo)
+   |
+   = help: Add `await`
+
+ℹ Suggested fix
+29 29 |     # TRIO105
+30 30 |     trio.aclose_forcefully(foo)
+31 31 |     trio.open_file(foo)
+32    |-    trio.open_ssl_over_tcp_listeners(foo, foo)
+   32 |+    await trio.open_ssl_over_tcp_listeners(foo, foo)
+33 33 |     trio.open_ssl_over_tcp_stream(foo, foo)
+34 34 |     trio.open_tcp_listeners(foo)
+35 35 |     trio.open_tcp_stream(foo, foo)
+
+TRIO105.py:33:5: TRIO105 [*] Call to `trio.open_ssl_over_tcp_stream` is not immediately awaited
+   |
+31 |     trio.open_file(foo)
+32 |     trio.open_ssl_over_tcp_listeners(foo, foo)
+33 |     trio.open_ssl_over_tcp_stream(foo, foo)
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ TRIO105
+34 |     trio.open_tcp_listeners(foo)
+35 |     trio.open_tcp_stream(foo, foo)
+   |
+   = help: Add `await`
+
+ℹ Suggested fix
+30 30 |     trio.aclose_forcefully(foo)
+31 31 |     trio.open_file(foo)
+32 32 |     trio.open_ssl_over_tcp_listeners(foo, foo)
+33    |-    trio.open_ssl_over_tcp_stream(foo, foo)
+   33 |+    await trio.open_ssl_over_tcp_stream(foo, foo)
+34 34 |     trio.open_tcp_listeners(foo)
+35 35 |     trio.open_tcp_stream(foo, foo)
+36 36 |     trio.open_unix_socket(foo)
+
+TRIO105.py:34:5: TRIO105 [*] Call to `trio.open_tcp_listeners` is not immediately awaited
+   |
+32 |     trio.open_ssl_over_tcp_listeners(foo, foo)
+33 |     trio.open_ssl_over_tcp_stream(foo, foo)
+34 |     trio.open_tcp_listeners(foo)
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ TRIO105
+35 |     trio.open_tcp_stream(foo, foo)
+36 |     trio.open_unix_socket(foo)
+   |
+   = help: Add `await`
+
+ℹ Suggested fix
+31 31 |     trio.open_file(foo)
+32 32 |     trio.open_ssl_over_tcp_listeners(foo, foo)
+33 33 |     trio.open_ssl_over_tcp_stream(foo, foo)
+34    |-    trio.open_tcp_listeners(foo)
+   34 |+    await trio.open_tcp_listeners(foo)
+35 35 |     trio.open_tcp_stream(foo, foo)
+36 36 |     trio.open_unix_socket(foo)
+37 37 |     trio.run_process(foo)
+
+TRIO105.py:35:5: TRIO105 [*] Call to `trio.open_tcp_stream` is not immediately awaited
+   |
+33 |     trio.open_ssl_over_tcp_stream(foo, foo)
+34 |     trio.open_tcp_listeners(foo)
+35 |     trio.open_tcp_stream(foo, foo)
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ TRIO105
+36 |     trio.open_unix_socket(foo)
+37 |     trio.run_process(foo)
+   |
+   = help: Add `await`
+
+ℹ Suggested fix
+32 32 |     trio.open_ssl_over_tcp_listeners(foo, foo)
+33 33 |     trio.open_ssl_over_tcp_stream(foo, foo)
+34 34 |     trio.open_tcp_listeners(foo)
+35    |-    trio.open_tcp_stream(foo, foo)
+   35 |+    await trio.open_tcp_stream(foo, foo)
+36 36 |     trio.open_unix_socket(foo)
+37 37 |     trio.run_process(foo)
+38 38 |     trio.serve_listeners(foo, foo)
+
+TRIO105.py:36:5: TRIO105 [*] Call to `trio.open_unix_socket` is not immediately awaited
+   |
+34 |     trio.open_tcp_listeners(foo)
+35 |     trio.open_tcp_stream(foo, foo)
+36 |     trio.open_unix_socket(foo)
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^ TRIO105
+37 |     trio.run_process(foo)
+38 |     trio.serve_listeners(foo, foo)
+   |
+   = help: Add `await`
+
+ℹ Suggested fix
+33 33 |     trio.open_ssl_over_tcp_stream(foo, foo)
+34 34 |     trio.open_tcp_listeners(foo)
+35 35 |     trio.open_tcp_stream(foo, foo)
+36    |-    trio.open_unix_socket(foo)
+   36 |+    await trio.open_unix_socket(foo)
+37 37 |     trio.run_process(foo)
+38 38 |     trio.serve_listeners(foo, foo)
+39 39 |     trio.serve_ssl_over_tcp(foo, foo, foo)
+
+TRIO105.py:37:5: TRIO105 [*] Call to `trio.run_process` is not immediately awaited
+   |
+35 |     trio.open_tcp_stream(foo, foo)
+36 |     trio.open_unix_socket(foo)
+37 |     trio.run_process(foo)
+   |     ^^^^^^^^^^^^^^^^^^^^^ TRIO105
+38 |     trio.serve_listeners(foo, foo)
+39 |     trio.serve_ssl_over_tcp(foo, foo, foo)
+   |
+   = help: Add `await`
+
+ℹ Suggested fix
+34 34 |     trio.open_tcp_listeners(foo)
+35 35 |     trio.open_tcp_stream(foo, foo)
+36 36 |     trio.open_unix_socket(foo)
+37    |-    trio.run_process(foo)
+   37 |+    await trio.run_process(foo)
+38 38 |     trio.serve_listeners(foo, foo)
+39 39 |     trio.serve_ssl_over_tcp(foo, foo, foo)
+40 40 |     trio.serve_tcp(foo, foo)
+
+TRIO105.py:38:5: TRIO105 [*] Call to `trio.serve_listeners` is not immediately awaited
+   |
+36 |     trio.open_unix_socket(foo)
+37 |     trio.run_process(foo)
+38 |     trio.serve_listeners(foo, foo)
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ TRIO105
+39 |     trio.serve_ssl_over_tcp(foo, foo, foo)
+40 |     trio.serve_tcp(foo, foo)
+   |
+   = help: Add `await`
+
+ℹ Suggested fix
+35 35 |     trio.open_tcp_stream(foo, foo)
+36 36 |     trio.open_unix_socket(foo)
+37 37 |     trio.run_process(foo)
+38    |-    trio.serve_listeners(foo, foo)
+   38 |+    await trio.serve_listeners(foo, foo)
+39 39 |     trio.serve_ssl_over_tcp(foo, foo, foo)
+40 40 |     trio.serve_tcp(foo, foo)
+41 41 |     trio.sleep(foo)
+
+TRIO105.py:39:5: TRIO105 [*] Call to `trio.serve_ssl_over_tcp` is not immediately awaited
+   |
+37 |     trio.run_process(foo)
+38 |     trio.serve_listeners(foo, foo)
+39 |     trio.serve_ssl_over_tcp(foo, foo, foo)
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ TRIO105
+40 |     trio.serve_tcp(foo, foo)
+41 |     trio.sleep(foo)
+   |
+   = help: Add `await`
+
+ℹ Suggested fix
+36 36 |     trio.open_unix_socket(foo)
+37 37 |     trio.run_process(foo)
+38 38 |     trio.serve_listeners(foo, foo)
+39    |-    trio.serve_ssl_over_tcp(foo, foo, foo)
+   39 |+    await trio.serve_ssl_over_tcp(foo, foo, foo)
+40 40 |     trio.serve_tcp(foo, foo)
+41 41 |     trio.sleep(foo)
+42 42 |     trio.sleep_forever()
+
+TRIO105.py:40:5: TRIO105 [*] Call to `trio.serve_tcp` is not immediately awaited
+   |
+38 |     trio.serve_listeners(foo, foo)
+39 |     trio.serve_ssl_over_tcp(foo, foo, foo)
+40 |     trio.serve_tcp(foo, foo)
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^ TRIO105
+41 |     trio.sleep(foo)
+42 |     trio.sleep_forever()
+   |
+   = help: Add `await`
+
+ℹ Suggested fix
+37 37 |     trio.run_process(foo)
+38 38 |     trio.serve_listeners(foo, foo)
+39 39 |     trio.serve_ssl_over_tcp(foo, foo, foo)
+40    |-    trio.serve_tcp(foo, foo)
+   40 |+    await trio.serve_tcp(foo, foo)
+41 41 |     trio.sleep(foo)
+42 42 |     trio.sleep_forever()
+43 43 |     trio.sleep_until(foo)
+
+TRIO105.py:41:5: TRIO105 [*] Call to `trio.sleep` is not immediately awaited
+   |
+39 |     trio.serve_ssl_over_tcp(foo, foo, foo)
+40 |     trio.serve_tcp(foo, foo)
+41 |     trio.sleep(foo)
+   |     ^^^^^^^^^^^^^^^ TRIO105
+42 |     trio.sleep_forever()
+43 |     trio.sleep_until(foo)
+   |
+   = help: Add `await`
+
+ℹ Suggested fix
+38 38 |     trio.serve_listeners(foo, foo)
+39 39 |     trio.serve_ssl_over_tcp(foo, foo, foo)
+40 40 |     trio.serve_tcp(foo, foo)
+41    |-    trio.sleep(foo)
+   41 |+    await trio.sleep(foo)
+42 42 |     trio.sleep_forever()
+43 43 |     trio.sleep_until(foo)
+44 44 |     trio.lowlevel.cancel_shielded_checkpoint()
+
+TRIO105.py:42:5: TRIO105 [*] Call to `trio.sleep_forever` is not immediately awaited
+   |
+40 |     trio.serve_tcp(foo, foo)
+41 |     trio.sleep(foo)
+42 |     trio.sleep_forever()
+   |     ^^^^^^^^^^^^^^^^^^^^ TRIO105
+43 |     trio.sleep_until(foo)
+44 |     trio.lowlevel.cancel_shielded_checkpoint()
+   |
+   = help: Add `await`
+
+ℹ Suggested fix
+39 39 |     trio.serve_ssl_over_tcp(foo, foo, foo)
+40 40 |     trio.serve_tcp(foo, foo)
+41 41 |     trio.sleep(foo)
+42    |-    trio.sleep_forever()
+   42 |+    await trio.sleep_forever()
+43 43 |     trio.sleep_until(foo)
+44 44 |     trio.lowlevel.cancel_shielded_checkpoint()
+45 45 |     trio.lowlevel.checkpoint()
+
+TRIO105.py:44:5: TRIO105 [*] Call to `trio.lowlevel.cancel_shielded_checkpoint` is not immediately awaited
+   |
+42 |     trio.sleep_forever()
+43 |     trio.sleep_until(foo)
+44 |     trio.lowlevel.cancel_shielded_checkpoint()
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ TRIO105
+45 |     trio.lowlevel.checkpoint()
+46 |     trio.lowlevel.checkpoint_if_cancelled()
+   |
+   = help: Add `await`
+
+ℹ Suggested fix
+41 41 |     trio.sleep(foo)
+42 42 |     trio.sleep_forever()
+43 43 |     trio.sleep_until(foo)
+44    |-    trio.lowlevel.cancel_shielded_checkpoint()
+   44 |+    await trio.lowlevel.cancel_shielded_checkpoint()
+45 45 |     trio.lowlevel.checkpoint()
+46 46 |     trio.lowlevel.checkpoint_if_cancelled()
+47 47 |     trio.lowlevel.open_process()
+
+TRIO105.py:45:5: TRIO105 [*] Call to `trio.lowlevel.checkpoint` is not immediately awaited
+   |
+43 |     trio.sleep_until(foo)
+44 |     trio.lowlevel.cancel_shielded_checkpoint()
+45 |     trio.lowlevel.checkpoint()
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^ TRIO105
+46 |     trio.lowlevel.checkpoint_if_cancelled()
+47 |     trio.lowlevel.open_process()
+   |
+   = help: Add `await`
+
+ℹ Suggested fix
+42 42 |     trio.sleep_forever()
+43 43 |     trio.sleep_until(foo)
+44 44 |     trio.lowlevel.cancel_shielded_checkpoint()
+45    |-    trio.lowlevel.checkpoint()
+   45 |+    await trio.lowlevel.checkpoint()
+46 46 |     trio.lowlevel.checkpoint_if_cancelled()
+47 47 |     trio.lowlevel.open_process()
+48 48 |     trio.lowlevel.permanently_detach_coroutine_object(foo)
+
+TRIO105.py:46:5: TRIO105 [*] Call to `trio.lowlevel.checkpoint_if_cancelled` is not immediately awaited
+   |
+44 |     trio.lowlevel.cancel_shielded_checkpoint()
+45 |     trio.lowlevel.checkpoint()
+46 |     trio.lowlevel.checkpoint_if_cancelled()
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ TRIO105
+47 |     trio.lowlevel.open_process()
+48 |     trio.lowlevel.permanently_detach_coroutine_object(foo)
+   |
+   = help: Add `await`
+
+ℹ Suggested fix
+43 43 |     trio.sleep_until(foo)
+44 44 |     trio.lowlevel.cancel_shielded_checkpoint()
+45 45 |     trio.lowlevel.checkpoint()
+46    |-    trio.lowlevel.checkpoint_if_cancelled()
+   46 |+    await trio.lowlevel.checkpoint_if_cancelled()
+47 47 |     trio.lowlevel.open_process()
+48 48 |     trio.lowlevel.permanently_detach_coroutine_object(foo)
+49 49 |     trio.lowlevel.reattach_detached_coroutine_object(foo, foo)
+
+TRIO105.py:47:5: TRIO105 [*] Call to `trio.lowlevel.open_process` is not immediately awaited
+   |
+45 |     trio.lowlevel.checkpoint()
+46 |     trio.lowlevel.checkpoint_if_cancelled()
+47 |     trio.lowlevel.open_process()
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ TRIO105
+48 |     trio.lowlevel.permanently_detach_coroutine_object(foo)
+49 |     trio.lowlevel.reattach_detached_coroutine_object(foo, foo)
+   |
+   = help: Add `await`
+
+ℹ Suggested fix
+44 44 |     trio.lowlevel.cancel_shielded_checkpoint()
+45 45 |     trio.lowlevel.checkpoint()
+46 46 |     trio.lowlevel.checkpoint_if_cancelled()
+47    |-    trio.lowlevel.open_process()
+   47 |+    await trio.lowlevel.open_process()
+48 48 |     trio.lowlevel.permanently_detach_coroutine_object(foo)
+49 49 |     trio.lowlevel.reattach_detached_coroutine_object(foo, foo)
+50 50 |     trio.lowlevel.temporarily_detach_coroutine_object(foo)
+
+TRIO105.py:48:5: TRIO105 [*] Call to `trio.lowlevel.permanently_detach_coroutine_object` is not immediately awaited
+   |
+46 |     trio.lowlevel.checkpoint_if_cancelled()
+47 |     trio.lowlevel.open_process()
+48 |     trio.lowlevel.permanently_detach_coroutine_object(foo)
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ TRIO105
+49 |     trio.lowlevel.reattach_detached_coroutine_object(foo, foo)
+50 |     trio.lowlevel.temporarily_detach_coroutine_object(foo)
+   |
+   = help: Add `await`
+
+ℹ Suggested fix
+45 45 |     trio.lowlevel.checkpoint()
+46 46 |     trio.lowlevel.checkpoint_if_cancelled()
+47 47 |     trio.lowlevel.open_process()
+48    |-    trio.lowlevel.permanently_detach_coroutine_object(foo)
+   48 |+    await trio.lowlevel.permanently_detach_coroutine_object(foo)
+49 49 |     trio.lowlevel.reattach_detached_coroutine_object(foo, foo)
+50 50 |     trio.lowlevel.temporarily_detach_coroutine_object(foo)
+51 51 |     trio.lowlevel.wait_readable(foo)
+
+TRIO105.py:49:5: TRIO105 [*] Call to `trio.lowlevel.reattach_detached_coroutine_object` is not immediately awaited
+   |
+47 |     trio.lowlevel.open_process()
+48 |     trio.lowlevel.permanently_detach_coroutine_object(foo)
+49 |     trio.lowlevel.reattach_detached_coroutine_object(foo, foo)
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ TRIO105
+50 |     trio.lowlevel.temporarily_detach_coroutine_object(foo)
+51 |     trio.lowlevel.wait_readable(foo)
+   |
+   = help: Add `await`
+
+ℹ Suggested fix
+46 46 |     trio.lowlevel.checkpoint_if_cancelled()
+47 47 |     trio.lowlevel.open_process()
+48 48 |     trio.lowlevel.permanently_detach_coroutine_object(foo)
+49    |-    trio.lowlevel.reattach_detached_coroutine_object(foo, foo)
+   49 |+    await trio.lowlevel.reattach_detached_coroutine_object(foo, foo)
+50 50 |     trio.lowlevel.temporarily_detach_coroutine_object(foo)
+51 51 |     trio.lowlevel.wait_readable(foo)
+52 52 |     trio.lowlevel.wait_task_rescheduled(foo)
+
+TRIO105.py:50:5: TRIO105 [*] Call to `trio.lowlevel.temporarily_detach_coroutine_object` is not immediately awaited
+   |
+48 |     trio.lowlevel.permanently_detach_coroutine_object(foo)
+49 |     trio.lowlevel.reattach_detached_coroutine_object(foo, foo)
+50 |     trio.lowlevel.temporarily_detach_coroutine_object(foo)
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ TRIO105
+51 |     trio.lowlevel.wait_readable(foo)
+52 |     trio.lowlevel.wait_task_rescheduled(foo)
+   |
+   = help: Add `await`
+
+ℹ Suggested fix
+47 47 |     trio.lowlevel.open_process()
+48 48 |     trio.lowlevel.permanently_detach_coroutine_object(foo)
+49 49 |     trio.lowlevel.reattach_detached_coroutine_object(foo, foo)
+50    |-    trio.lowlevel.temporarily_detach_coroutine_object(foo)
+   50 |+    await trio.lowlevel.temporarily_detach_coroutine_object(foo)
+51 51 |     trio.lowlevel.wait_readable(foo)
+52 52 |     trio.lowlevel.wait_task_rescheduled(foo)
+53 53 |     trio.lowlevel.wait_writable(foo)
+
+TRIO105.py:51:5: TRIO105 [*] Call to `trio.lowlevel.wait_readable` is not immediately awaited
+   |
+49 |     trio.lowlevel.reattach_detached_coroutine_object(foo, foo)
+50 |     trio.lowlevel.temporarily_detach_coroutine_object(foo)
+51 |     trio.lowlevel.wait_readable(foo)
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ TRIO105
+52 |     trio.lowlevel.wait_task_rescheduled(foo)
+53 |     trio.lowlevel.wait_writable(foo)
+   |
+   = help: Add `await`
+
+ℹ Suggested fix
+48 48 |     trio.lowlevel.permanently_detach_coroutine_object(foo)
+49 49 |     trio.lowlevel.reattach_detached_coroutine_object(foo, foo)
+50 50 |     trio.lowlevel.temporarily_detach_coroutine_object(foo)
+51    |-    trio.lowlevel.wait_readable(foo)
+   51 |+    await trio.lowlevel.wait_readable(foo)
+52 52 |     trio.lowlevel.wait_task_rescheduled(foo)
+53 53 |     trio.lowlevel.wait_writable(foo)
+54 54 | 
+
+TRIO105.py:52:5: TRIO105 [*] Call to `trio.lowlevel.wait_task_rescheduled` is not immediately awaited
+   |
+50 |     trio.lowlevel.temporarily_detach_coroutine_object(foo)
+51 |     trio.lowlevel.wait_readable(foo)
+52 |     trio.lowlevel.wait_task_rescheduled(foo)
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ TRIO105
+53 |     trio.lowlevel.wait_writable(foo)
+   |
+   = help: Add `await`
+
+ℹ Suggested fix
+49 49 |     trio.lowlevel.reattach_detached_coroutine_object(foo, foo)
+50 50 |     trio.lowlevel.temporarily_detach_coroutine_object(foo)
+51 51 |     trio.lowlevel.wait_readable(foo)
+52    |-    trio.lowlevel.wait_task_rescheduled(foo)
+   52 |+    await trio.lowlevel.wait_task_rescheduled(foo)
+53 53 |     trio.lowlevel.wait_writable(foo)
+54 54 | 
+55 55 |     async with await trio.open_file(foo):  # Ok
+
+TRIO105.py:53:5: TRIO105 [*] Call to `trio.lowlevel.wait_writable` is not immediately awaited
+   |
+51 |     trio.lowlevel.wait_readable(foo)
+52 |     trio.lowlevel.wait_task_rescheduled(foo)
+53 |     trio.lowlevel.wait_writable(foo)
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ TRIO105
+54 | 
+55 |     async with await trio.open_file(foo):  # Ok
+   |
+   = help: Add `await`
+
+ℹ Suggested fix
+50 50 |     trio.lowlevel.temporarily_detach_coroutine_object(foo)
+51 51 |     trio.lowlevel.wait_readable(foo)
+52 52 |     trio.lowlevel.wait_task_rescheduled(foo)
+53    |-    trio.lowlevel.wait_writable(foo)
+   53 |+    await trio.lowlevel.wait_writable(foo)
+54 54 | 
+55 55 |     async with await trio.open_file(foo):  # Ok
+56 56 |         pass
+
+TRIO105.py:58:16: TRIO105 [*] Call to `trio.open_file` is not immediately awaited
+   |
+56 |         pass
+57 | 
+58 |     async with trio.open_file(foo):  # TRIO105
+   |                ^^^^^^^^^^^^^^^^^^^ TRIO105
+59 |         pass
+   |
+   = help: Add `await`
+
+ℹ Suggested fix
+55 55 |     async with await trio.open_file(foo):  # Ok
+56 56 |         pass
+57 57 | 
+58    |-    async with trio.open_file(foo):  # TRIO105
+   58 |+    async with await trio.open_file(foo):  # TRIO105
+59 59 |         pass
+60 60 | 
+61 61 | 
+
+TRIO105.py:64:5: TRIO105 Call to `trio.open_file` is not immediately awaited
+   |
+62 | def func() -> None:
+63 |     # TRIO105 (without fix)
+64 |     trio.open_file(foo)
+   |     ^^^^^^^^^^^^^^^^^^^ TRIO105
+   |
+   = help: Add `await`
+
+

crates/ruff_linter/src/rules/flake8_trio/snapshots/ruff_linter__rules__flake8_trio__tests__TRIO115_TRIO115.py.snap

@@ -0,0 +1,119 @@
+---
+source: crates/ruff_linter/src/rules/flake8_trio/mod.rs
+---
+TRIO115.py:6:11: TRIO115 [*] Use `trio.lowlevel.checkpoint()` instead of `trio.sleep(0)`
+  |
+5 | async def func():
+6 |     await trio.sleep(0)  # TRIO115
+  |           ^^^^^^^^^^^^^ TRIO115
+7 |     await trio.sleep(1)  # OK
+8 |     await trio.sleep(0, 1)  # OK
+  |
+  = help: Replace with `trio.lowlevel.checkpoint()`
+
+ℹ Fix
+3 3 | 
+4 4 | 
+5 5 | async def func():
+6   |-    await trio.sleep(0)  # TRIO115
+  6 |+    await trio.lowlevel.checkpoint  # TRIO115
+7 7 |     await trio.sleep(1)  # OK
+8 8 |     await trio.sleep(0, 1)  # OK
+9 9 |     await trio.sleep(...)  # OK
+
+TRIO115.py:12:5: TRIO115 [*] Use `trio.lowlevel.checkpoint()` instead of `trio.sleep(0)`
+   |
+10 |     await trio.sleep()  # OK
+11 | 
+12 |     trio.sleep(0)  # TRIO115
+   |     ^^^^^^^^^^^^^ TRIO115
+13 |     foo = 0
+14 |     trio.sleep(foo)  # TRIO115
+   |
+   = help: Replace with `trio.lowlevel.checkpoint()`
+
+ℹ Fix
+9  9  |     await trio.sleep(...)  # OK
+10 10 |     await trio.sleep()  # OK
+11 11 | 
+12    |-    trio.sleep(0)  # TRIO115
+   12 |+    trio.lowlevel.checkpoint  # TRIO115
+13 13 |     foo = 0
+14 14 |     trio.sleep(foo)  # TRIO115
+15 15 |     trio.sleep(1)  # OK
+
+TRIO115.py:14:5: TRIO115 [*] Use `trio.lowlevel.checkpoint()` instead of `trio.sleep(0)`
+   |
+12 |     trio.sleep(0)  # TRIO115
+13 |     foo = 0
+14 |     trio.sleep(foo)  # TRIO115
+   |     ^^^^^^^^^^^^^^^ TRIO115
+15 |     trio.sleep(1)  # OK
+16 |     time.sleep(0)  # OK
+   |
+   = help: Replace with `trio.lowlevel.checkpoint()`
+
+ℹ Fix
+11 11 | 
+12 12 |     trio.sleep(0)  # TRIO115
+13 13 |     foo = 0
+14    |-    trio.sleep(foo)  # TRIO115
+   14 |+    trio.lowlevel.checkpoint  # TRIO115
+15 15 |     trio.sleep(1)  # OK
+16 16 |     time.sleep(0)  # OK
+17 17 | 
+
+TRIO115.py:18:5: TRIO115 [*] Use `trio.lowlevel.checkpoint()` instead of `trio.sleep(0)`
+   |
+16 |     time.sleep(0)  # OK
+17 | 
+18 |     sleep(0)  # TRIO115
+   |     ^^^^^^^^ TRIO115
+19 | 
+20 |     bar = "bar"
+   |
+   = help: Replace with `trio.lowlevel.checkpoint()`
+
+ℹ Fix
+15 15 |     trio.sleep(1)  # OK
+16 16 |     time.sleep(0)  # OK
+17 17 | 
+18    |-    sleep(0)  # TRIO115
+   18 |+    trio.lowlevel.checkpoint  # TRIO115
+19 19 | 
+20 20 |     bar = "bar"
+21 21 |     trio.sleep(bar)
+
+TRIO115.py:24:1: TRIO115 [*] Use `trio.lowlevel.checkpoint()` instead of `trio.sleep(0)`
+   |
+24 | trio.sleep(0)  # TRIO115
+   | ^^^^^^^^^^^^^ TRIO115
+   |
+   = help: Replace with `trio.lowlevel.checkpoint()`
+
+ℹ Fix
+21 21 |     trio.sleep(bar)
+22 22 | 
+23 23 | 
+24    |-trio.sleep(0)  # TRIO115
+   24 |+trio.lowlevel.checkpoint  # TRIO115
+25 25 | 
+26 26 | 
+27 27 | def func():
+
+TRIO115.py:28:14: TRIO115 [*] Use `trio.lowlevel.checkpoint()` instead of `trio.sleep(0)`
+   |
+27 | def func():
+28 |     trio.run(trio.sleep(0))  # TRIO115
+   |              ^^^^^^^^^^^^^ TRIO115
+   |
+   = help: Replace with `trio.lowlevel.checkpoint()`
+
+ℹ Fix
+25 25 | 
+26 26 | 
+27 27 | def func():
+28    |-    trio.run(trio.sleep(0))  # TRIO115
+   28 |+    trio.run(trio.lowlevel.checkpoint)  # TRIO115
+
+

crates/ruff_linter/src/rules/perflint/rules/manual_dict_comprehension.rs

@@ -4,7 +4,6 @@ use ruff_python_ast::comparable::ComparableExpr;
 use ruff_python_ast::helpers::any_over_expr;
 use ruff_python_ast::{self as ast, Expr, Stmt};
 use ruff_python_semantic::analyze::typing::is_dict;
-use ruff_python_semantic::Binding;
 
 use crate::checkers::ast::Checker;
 
@@ -129,22 +128,16 @@ pub(crate) fn manual_dict_comprehension(checker: &mut Checker, target: &Expr, bo
     }
 
     // Exclude non-dictionary value.
-    let Expr::Name(ast::ExprName {
-        id: subscript_name, ..
-    }) = subscript_value.as_ref()
+    let Some(name) = subscript_value.as_name_expr() else {
+        return;
+    };
+    let Some(binding) = checker
+        .semantic()
+        .only_binding(name)
+        .map(|id| checker.semantic().binding(id))
     else {
         return;
     };
-    let scope = checker.semantic().current_scope();
-    let bindings: Vec<&Binding> = scope
-        .get_all(subscript_name)
-        .map(|binding_id| checker.semantic().binding(binding_id))
-        .collect();
-
-    let [binding] = bindings.as_slice() else {
-        return;
-    };
-
     if !is_dict(binding, checker.semantic()) {
         return;
     }
@@ -165,8 +158,7 @@ pub(crate) fn manual_dict_comprehension(checker: &mut Checker, target: &Expr, bo
     // ```
     if if_test.is_some_and(|test| {
         any_over_expr(test, &|expr| {
-            expr.as_name_expr()
-                .is_some_and(|expr| expr.id == *subscript_name)
+            ComparableExpr::from(expr) == ComparableExpr::from(name)
         })
     }) {
         return;

crates/ruff_linter/src/rules/perflint/rules/manual_list_comprehension.rs

@@ -5,7 +5,6 @@ use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::comparable::ComparableExpr;
 use ruff_python_ast::helpers::any_over_expr;
 use ruff_python_semantic::analyze::typing::is_list;
-use ruff_python_semantic::Binding;
 
 use crate::checkers::ast::Checker;
 
@@ -144,20 +143,16 @@ pub(crate) fn manual_list_comprehension(checker: &mut Checker, target: &Expr, bo
     }
 
     // Avoid non-list values.
-    let Expr::Name(ast::ExprName { id, .. }) = value.as_ref() else {
+    let Some(name) = value.as_name_expr() else {
         return;
     };
-    let bindings: Vec<&Binding> = checker
+    let Some(binding) = checker
         .semantic()
-        .current_scope()
-        .get_all(id)
-        .map(|binding_id| checker.semantic().binding(binding_id))
-        .collect();
-
-    let [binding] = bindings.as_slice() else {
+        .only_binding(name)
+        .map(|id| checker.semantic().binding(id))
+    else {
         return;
     };
-
     if !is_list(binding, checker.semantic()) {
         return;
     }
@@ -176,15 +171,12 @@ pub(crate) fn manual_list_comprehension(checker: &mut Checker, target: &Expr, bo
     // ```python
     // filtered = [x for x in y if x in filtered]
     // ```
-    if let Some(value_name) = value.as_name_expr() {
-        if if_test.is_some_and(|test| {
-            any_over_expr(test, &|expr| {
-                expr.as_name_expr()
-                    .is_some_and(|expr| expr.id == value_name.id)
-            })
-        }) {
-            return;
-        }
+    if if_test.is_some_and(|test| {
+        any_over_expr(test, &|expr| {
+            expr.as_name_expr().is_some_and(|expr| expr.id == name.id)
+        })
+    }) {
+        return;
     }
 
     checker

crates/ruff_linter/src/rules/perflint/rules/manual_list_copy.rs

@@ -3,7 +3,6 @@ use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::helpers::any_over_expr;
 use ruff_python_ast::{self as ast, Arguments, Expr, Stmt};
 use ruff_python_semantic::analyze::typing::is_list;
-use ruff_python_semantic::Binding;
 
 use crate::checkers::ast::Checker;
 
@@ -102,20 +101,16 @@ pub(crate) fn manual_list_copy(checker: &mut Checker, target: &Expr, body: &[Stm
     }
 
     // Avoid non-list values.
-    let Expr::Name(ast::ExprName { id, .. }) = value.as_ref() else {
+    let Some(name) = value.as_name_expr() else {
         return;
     };
-    let bindings: Vec<&Binding> = checker
+    let Some(binding) = checker
         .semantic()
-        .current_scope()
-        .get_all(id)
-        .map(|binding_id| checker.semantic().binding(binding_id))
-        .collect();
-
-    let [binding] = bindings.as_slice() else {
+        .only_binding(name)
+        .map(|id| checker.semantic().binding(id))
+    else {
         return;
     };
-
     if !is_list(binding, checker.semantic()) {
         return;
     }

crates/ruff_linter/src/rules/pycodestyle/rules/compound_statements.rs

@@ -24,7 +24,7 @@ use ruff_source_file::Locator;
 /// if foo == "blah":
 ///     do_blah_thing()
 /// ```
-
+///
 /// [PEP 8]: https://peps.python.org/pep-0008/#other-recommendations
 #[violation]
 pub struct MultipleStatementsOnOneLineColon;
@@ -206,12 +206,13 @@ pub(crate) fn compound_statements(
                 {
                     colon = Some((range.start(), range.end()));
 
-                    // Allow `class C: ...`-style definitions in stubs.
-                    allow_ellipsis = class.is_some();
+                    // Allow `class C: ...`-style definitions.
+                    allow_ellipsis = true;
                 }
             }
             Tok::Semi => {
                 semi = Some((range.start(), range.end()));
+                allow_ellipsis = false;
             }
             Tok::Comment(..) | Tok::Indent | Tok::Dedent | Tok::NonLogicalNewline => {}
             _ => {
@@ -223,6 +224,7 @@ pub(crate) fn compound_statements(
 
                     // Reset.
                     semi = None;
+                    allow_ellipsis = false;
                 }
 
                 if let Some((start, end)) = colon {
@@ -245,6 +247,7 @@ pub(crate) fn compound_statements(
                     try_ = None;
                     while_ = None;
                     with = None;
+                    allow_ellipsis = false;
                 }
             }
         }

crates/ruff_linter/src/rules/pycodestyle/rules/type_comparison.rs

@@ -138,6 +138,7 @@ fn deprecated_type_comparison(checker: &mut Checker, compare: &ast::ExprCompare)
                         | "list"
                         | "dict"
                         | "set"
+                        | "memoryview"
                 ) && checker.semantic().is_builtin(id)
                 {
                     checker.diagnostics.push(Diagnostic::new(
@@ -197,7 +198,98 @@ fn is_type(expr: &Expr, semantic: &SemanticModel) -> bool {
             // Ex) `type(obj) == int`
             matches!(
                 id.as_str(),
-                "int" | "str" | "float" | "bool" | "complex" | "bytes" | "list" | "dict" | "set"
+                "bool"
+                    | "bytearray"
+                    | "bytes"
+                    | "classmethod"
+                    | "complex"
+                    | "dict"
+                    | "enumerate"
+                    | "filter"
+                    | "float"
+                    | "frozenset"
+                    | "int"
+                    | "list"
+                    | "map"
+                    | "memoryview"
+                    | "object"
+                    | "property"
+                    | "range"
+                    | "reversed"
+                    | "set"
+                    | "slice"
+                    | "staticmethod"
+                    | "str"
+                    | "super"
+                    | "tuple"
+                    | "type"
+                    | "zip"
+                    | "ArithmeticError"
+                    | "AssertionError"
+                    | "AttributeError"
+                    | "BaseException"
+                    | "BlockingIOError"
+                    | "BrokenPipeError"
+                    | "BufferError"
+                    | "BytesWarning"
+                    | "ChildProcessError"
+                    | "ConnectionAbortedError"
+                    | "ConnectionError"
+                    | "ConnectionRefusedError"
+                    | "ConnectionResetError"
+                    | "DeprecationWarning"
+                    | "EnvironmentError"
+                    | "EOFError"
+                    | "Exception"
+                    | "FileExistsError"
+                    | "FileNotFoundError"
+                    | "FloatingPointError"
+                    | "FutureWarning"
+                    | "GeneratorExit"
+                    | "ImportError"
+                    | "ImportWarning"
+                    | "IndentationError"
+                    | "IndexError"
+                    | "InterruptedError"
+                    | "IOError"
+                    | "IsADirectoryError"
+                    | "KeyboardInterrupt"
+                    | "KeyError"
+                    | "LookupError"
+                    | "MemoryError"
+                    | "ModuleNotFoundError"
+                    | "NameError"
+                    | "NotADirectoryError"
+                    | "NotImplementedError"
+                    | "OSError"
+                    | "OverflowError"
+                    | "PendingDeprecationWarning"
+                    | "PermissionError"
+                    | "ProcessLookupError"
+                    | "RecursionError"
+                    | "ReferenceError"
+                    | "ResourceWarning"
+                    | "RuntimeError"
+                    | "RuntimeWarning"
+                    | "StopAsyncIteration"
+                    | "StopIteration"
+                    | "SyntaxError"
+                    | "SyntaxWarning"
+                    | "SystemError"
+                    | "SystemExit"
+                    | "TabError"
+                    | "TimeoutError"
+                    | "TypeError"
+                    | "UnboundLocalError"
+                    | "UnicodeDecodeError"
+                    | "UnicodeEncodeError"
+                    | "UnicodeError"
+                    | "UnicodeTranslateError"
+                    | "UnicodeWarning"
+                    | "UserWarning"
+                    | "ValueError"
+                    | "Warning"
+                    | "ZeroDivisionError"
             ) && semantic.is_builtin(id)
         }
         _ => false,

crates/ruff_linter/src/rules/pycodestyle/snapshots/ruff_linter__rules__pycodestyle__tests__E703_E70.py.snap

@@ -92,6 +92,8 @@ E70.py:71:4: E703 [*] Statement ends with an unnecessary semicolon
 70 | a = \
 71 |   5;
    |    ^ E703
+72 | #:
+73 | with x(y) as z: ...
    |
    = help: Remove unnecessary semicolon
 
@@ -101,5 +103,7 @@ E70.py:71:4: E703 [*] Statement ends with an unnecessary semicolon
 70 70 | a = \
 71    |-  5;
    71 |+  5
+72 72 | #:
+73 73 | with x(y) as z: ...
 
 

crates/ruff_linter/src/rules/pycodestyle/snapshots/ruff_linter__rules__pycodestyle__tests__E721_E721.py.snap

@@ -17,144 +17,154 @@ E721.py:5:4: E721 Do not compare types, use `isinstance()`
 5 | if type(res) != type(""):
   |    ^^^^^^^^^^^^^^^^^^^^^ E721
 6 |     pass
-7 | #: Okay
+7 | #: E721
   |
 
-E721.py:15:4: E721 Do not compare types, use `isinstance()`
+E721.py:8:4: E721 Do not compare types, use `isinstance()`
    |
-13 | import types
-14 | 
-15 | if type(res) is not types.ListType:
+ 6 |     pass
+ 7 | #: E721
+ 8 | if type(res) == memoryview:
+   |    ^^^^^^^^^^^^^^^^^^^^^^^ E721
+ 9 |     pass
+10 | #: Okay
+   |
+
+E721.py:18:4: E721 Do not compare types, use `isinstance()`
+   |
+16 | import types
+17 | 
+18 | if type(res) is not types.ListType:
    |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ E721
-16 |     pass
-17 | #: E721
+19 |     pass
+20 | #: E721
    |
 
-E721.py:18:8: E721 Do not compare types, use `isinstance()`
+E721.py:21:8: E721 Do not compare types, use `isinstance()`
    |
-16 |     pass
-17 | #: E721
-18 | assert type(res) == type(False) or type(res) == type(None)
+19 |     pass
+20 | #: E721
+21 | assert type(res) == type(False) or type(res) == type(None)
    |        ^^^^^^^^^^^^^^^^^^^^^^^^ E721
-19 | #: E721
-20 | assert type(res) == type([])
+22 | #: E721
+23 | assert type(res) == type([])
    |
 
-E721.py:20:8: E721 Do not compare types, use `isinstance()`
+E721.py:23:8: E721 Do not compare types, use `isinstance()`
    |
-18 | assert type(res) == type(False) or type(res) == type(None)
-19 | #: E721
-20 | assert type(res) == type([])
+21 | assert type(res) == type(False) or type(res) == type(None)
+22 | #: E721
+23 | assert type(res) == type([])
    |        ^^^^^^^^^^^^^^^^^^^^^ E721
-21 | #: E721
-22 | assert type(res) == type(())
+24 | #: E721
+25 | assert type(res) == type(())
    |
 
-E721.py:22:8: E721 Do not compare types, use `isinstance()`
+E721.py:25:8: E721 Do not compare types, use `isinstance()`
    |
-20 | assert type(res) == type([])
-21 | #: E721
-22 | assert type(res) == type(())
+23 | assert type(res) == type([])
+24 | #: E721
+25 | assert type(res) == type(())
    |        ^^^^^^^^^^^^^^^^^^^^^ E721
-23 | #: E721
-24 | assert type(res) == type((0,))
+26 | #: E721
+27 | assert type(res) == type((0,))
    |
 
-E721.py:24:8: E721 Do not compare types, use `isinstance()`
+E721.py:27:8: E721 Do not compare types, use `isinstance()`
    |
-22 | assert type(res) == type(())
-23 | #: E721
-24 | assert type(res) == type((0,))
+25 | assert type(res) == type(())
+26 | #: E721
+27 | assert type(res) == type((0,))
    |        ^^^^^^^^^^^^^^^^^^^^^^^ E721
-25 | #: E721
-26 | assert type(res) == type((0))
+28 | #: E721
+29 | assert type(res) == type((0))
    |
 
-E721.py:26:8: E721 Do not compare types, use `isinstance()`
+E721.py:29:8: E721 Do not compare types, use `isinstance()`
    |
-24 | assert type(res) == type((0,))
-25 | #: E721
-26 | assert type(res) == type((0))
+27 | assert type(res) == type((0,))
+28 | #: E721
+29 | assert type(res) == type((0))
    |        ^^^^^^^^^^^^^^^^^^^^^^ E721
-27 | #: E721
-28 | assert type(res) != type((1, ))
+30 | #: E721
+31 | assert type(res) != type((1, ))
    |
 
-E721.py:28:8: E721 Do not compare types, use `isinstance()`
+E721.py:31:8: E721 Do not compare types, use `isinstance()`
    |
-26 | assert type(res) == type((0))
-27 | #: E721
-28 | assert type(res) != type((1, ))
+29 | assert type(res) == type((0))
+30 | #: E721
+31 | assert type(res) != type((1, ))
    |        ^^^^^^^^^^^^^^^^^^^^^^^^ E721
-29 | #: Okay
-30 | assert type(res) is type((1, ))
+32 | #: Okay
+33 | assert type(res) is type((1, ))
    |
 
-E721.py:30:8: E721 Do not compare types, use `isinstance()`
+E721.py:33:8: E721 Do not compare types, use `isinstance()`
    |
-28 | assert type(res) != type((1, ))
-29 | #: Okay
-30 | assert type(res) is type((1, ))
+31 | assert type(res) != type((1, ))
+32 | #: Okay
+33 | assert type(res) is type((1, ))
    |        ^^^^^^^^^^^^^^^^^^^^^^^^ E721
-31 | #: Okay
-32 | assert type(res) is not type((1, ))
+34 | #: Okay
+35 | assert type(res) is not type((1, ))
    |
 
-E721.py:32:8: E721 Do not compare types, use `isinstance()`
+E721.py:35:8: E721 Do not compare types, use `isinstance()`
    |
-30 | assert type(res) is type((1, ))
-31 | #: Okay
-32 | assert type(res) is not type((1, ))
+33 | assert type(res) is type((1, ))
+34 | #: Okay
+35 | assert type(res) is not type((1, ))
    |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ E721
-33 | #: E211 E721
-34 | assert type(res) == type ([2, ])
+36 | #: E211 E721
+37 | assert type(res) == type ([2, ])
    |
 
-E721.py:34:8: E721 Do not compare types, use `isinstance()`
+E721.py:37:8: E721 Do not compare types, use `isinstance()`
    |
-32 | assert type(res) is not type((1, ))
-33 | #: E211 E721
-34 | assert type(res) == type ([2, ])
+35 | assert type(res) is not type((1, ))
+36 | #: E211 E721
+37 | assert type(res) == type ([2, ])
    |        ^^^^^^^^^^^^^^^^^^^^^^^^^ E721
-35 | #: E201 E201 E202 E721
-36 | assert type(res) == type( ( ) )
+38 | #: E201 E201 E202 E721
+39 | assert type(res) == type( ( ) )
    |
 
-E721.py:36:8: E721 Do not compare types, use `isinstance()`
+E721.py:39:8: E721 Do not compare types, use `isinstance()`
    |
-34 | assert type(res) == type ([2, ])
-35 | #: E201 E201 E202 E721
-36 | assert type(res) == type( ( ) )
+37 | assert type(res) == type ([2, ])
+38 | #: E201 E201 E202 E721
+39 | assert type(res) == type( ( ) )
    |        ^^^^^^^^^^^^^^^^^^^^^^^^ E721
-37 | #: E201 E202 E721
-38 | assert type(res) == type( (0, ) )
+40 | #: E201 E202 E721
+41 | assert type(res) == type( (0, ) )
    |
 
-E721.py:38:8: E721 Do not compare types, use `isinstance()`
+E721.py:41:8: E721 Do not compare types, use `isinstance()`
    |
-36 | assert type(res) == type( ( ) )
-37 | #: E201 E202 E721
-38 | assert type(res) == type( (0, ) )
+39 | assert type(res) == type( ( ) )
+40 | #: E201 E202 E721
+41 | assert type(res) == type( (0, ) )
    |        ^^^^^^^^^^^^^^^^^^^^^^^^^^ E721
-39 | #:
+42 | #:
    |
 
-E721.py:96:12: E721 Do not compare types, use `isinstance()`
-   |
-94 |     def asdf(self, value: str | None):
-95 |         #: E721
-96 |         if type(value) is str:
-   |            ^^^^^^^^^^^^^^^^^^ E721
-97 |             ...
-   |
-
-E721.py:106:12: E721 Do not compare types, use `isinstance()`
+E721.py:107:12: E721 Do not compare types, use `isinstance()`
     |
-104 |     def asdf(self, value: str | None):
-105 |         #: E721
-106 |         if type(value) is str:
+105 |     def asdf(self, value: str | None):
+106 |         #: E721
+107 |         if type(value) is str:
     |            ^^^^^^^^^^^^^^^^^^ E721
-107 |             ...
+108 |             ...
+    |
+
+E721.py:117:12: E721 Do not compare types, use `isinstance()`
+    |
+115 |     def asdf(self, value: str | None):
+116 |         #: E721
+117 |         if type(value) is str:
+    |            ^^^^^^^^^^^^^^^^^^ E721
+118 |             ...
     |
 
 

crates/ruff_linter/src/rules/pycodestyle/snapshots/ruff_linter__rules__pycodestyle__tests__preview__E721_E721.py.snap

@@ -17,96 +17,116 @@ E721.py:5:4: E721 Use `is` and `is not` for type comparisons, or `isinstance()`
 5 | if type(res) != type(""):
   |    ^^^^^^^^^^^^^^^^^^^^^ E721
 6 |     pass
-7 | #: Okay
+7 | #: E721
   |
 
-E721.py:18:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
+E721.py:8:4: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
    |
-16 |     pass
-17 | #: E721
-18 | assert type(res) == type(False) or type(res) == type(None)
+ 6 |     pass
+ 7 | #: E721
+ 8 | if type(res) == memoryview:
+   |    ^^^^^^^^^^^^^^^^^^^^^^^ E721
+ 9 |     pass
+10 | #: Okay
+   |
+
+E721.py:21:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
+   |
+19 |     pass
+20 | #: E721
+21 | assert type(res) == type(False) or type(res) == type(None)
    |        ^^^^^^^^^^^^^^^^^^^^^^^^ E721
-19 | #: E721
-20 | assert type(res) == type([])
+22 | #: E721
+23 | assert type(res) == type([])
    |
 
-E721.py:20:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
+E721.py:23:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
    |
-18 | assert type(res) == type(False) or type(res) == type(None)
-19 | #: E721
-20 | assert type(res) == type([])
+21 | assert type(res) == type(False) or type(res) == type(None)
+22 | #: E721
+23 | assert type(res) == type([])
    |        ^^^^^^^^^^^^^^^^^^^^^ E721
-21 | #: E721
-22 | assert type(res) == type(())
+24 | #: E721
+25 | assert type(res) == type(())
    |
 
-E721.py:22:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
+E721.py:25:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
    |
-20 | assert type(res) == type([])
-21 | #: E721
-22 | assert type(res) == type(())
+23 | assert type(res) == type([])
+24 | #: E721
+25 | assert type(res) == type(())
    |        ^^^^^^^^^^^^^^^^^^^^^ E721
-23 | #: E721
-24 | assert type(res) == type((0,))
+26 | #: E721
+27 | assert type(res) == type((0,))
    |
 
-E721.py:24:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
+E721.py:27:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
    |
-22 | assert type(res) == type(())
-23 | #: E721
-24 | assert type(res) == type((0,))
+25 | assert type(res) == type(())
+26 | #: E721
+27 | assert type(res) == type((0,))
    |        ^^^^^^^^^^^^^^^^^^^^^^^ E721
-25 | #: E721
-26 | assert type(res) == type((0))
+28 | #: E721
+29 | assert type(res) == type((0))
    |
 
-E721.py:26:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
+E721.py:29:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
    |
-24 | assert type(res) == type((0,))
-25 | #: E721
-26 | assert type(res) == type((0))
+27 | assert type(res) == type((0,))
+28 | #: E721
+29 | assert type(res) == type((0))
    |        ^^^^^^^^^^^^^^^^^^^^^^ E721
-27 | #: E721
-28 | assert type(res) != type((1, ))
+30 | #: E721
+31 | assert type(res) != type((1, ))
    |
 
-E721.py:28:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
+E721.py:31:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
    |
-26 | assert type(res) == type((0))
-27 | #: E721
-28 | assert type(res) != type((1, ))
+29 | assert type(res) == type((0))
+30 | #: E721
+31 | assert type(res) != type((1, ))
    |        ^^^^^^^^^^^^^^^^^^^^^^^^ E721
-29 | #: Okay
-30 | assert type(res) is type((1, ))
+32 | #: Okay
+33 | assert type(res) is type((1, ))
    |
 
-E721.py:34:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
+E721.py:37:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
    |
-32 | assert type(res) is not type((1, ))
-33 | #: E211 E721
-34 | assert type(res) == type ([2, ])
+35 | assert type(res) is not type((1, ))
+36 | #: E211 E721
+37 | assert type(res) == type ([2, ])
    |        ^^^^^^^^^^^^^^^^^^^^^^^^^ E721
-35 | #: E201 E201 E202 E721
-36 | assert type(res) == type( ( ) )
+38 | #: E201 E201 E202 E721
+39 | assert type(res) == type( ( ) )
    |
 
-E721.py:36:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
+E721.py:39:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
    |
-34 | assert type(res) == type ([2, ])
-35 | #: E201 E201 E202 E721
-36 | assert type(res) == type( ( ) )
+37 | assert type(res) == type ([2, ])
+38 | #: E201 E201 E202 E721
+39 | assert type(res) == type( ( ) )
    |        ^^^^^^^^^^^^^^^^^^^^^^^^ E721
-37 | #: E201 E202 E721
-38 | assert type(res) == type( (0, ) )
+40 | #: E201 E202 E721
+41 | assert type(res) == type( (0, ) )
    |
 
-E721.py:38:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
+E721.py:41:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
    |
-36 | assert type(res) == type( ( ) )
-37 | #: E201 E202 E721
-38 | assert type(res) == type( (0, ) )
+39 | assert type(res) == type( ( ) )
+40 | #: E201 E202 E721
+41 | assert type(res) == type( (0, ) )
    |        ^^^^^^^^^^^^^^^^^^^^^^^^^^ E721
-39 | #:
+42 | #:
+   |
+
+E721.py:59:4: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
+   |
+57 |     pass
+58 | #: E721
+59 | if type(res) == type:
+   |    ^^^^^^^^^^^^^^^^^ E721
+60 |     pass
+61 | #: Okay
    |
 
 

crates/ruff_linter/src/rules/pydocstyle/rules/backslashes.rs

@@ -1,6 +1,6 @@
 use memchr::memchr_iter;
 
-use ruff_diagnostics::{AlwaysFixableViolation, Diagnostic, Edit, Fix};
+use ruff_diagnostics::{Diagnostic, Edit, Fix, FixAvailability, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_text_size::Ranged;
 
@@ -46,14 +46,16 @@ use crate::docstrings::Docstring;
 #[violation]
 pub struct EscapeSequenceInDocstring;
 
-impl AlwaysFixableViolation for EscapeSequenceInDocstring {
+impl Violation for EscapeSequenceInDocstring {
+    const FIX_AVAILABILITY: FixAvailability = FixAvailability::Sometimes;
+
     #[derive_message_formats]
     fn message(&self) -> String {
         format!(r#"Use `r"""` if any backslashes in a docstring"#)
     }
 
-    fn fix_title(&self) -> String {
-        format!(r#"Add `r` prefix"#)
+    fn fix_title(&self) -> Option<String> {
+        Some(format!(r#"Add `r` prefix"#))
     }
 }
 
@@ -74,10 +76,12 @@ pub(crate) fn backslashes(checker: &mut Checker, docstring: &Docstring) {
     }) {
         let mut diagnostic = Diagnostic::new(EscapeSequenceInDocstring, docstring.range());
 
-        diagnostic.set_fix(Fix::unsafe_edit(Edit::range_replacement(
-            "r".to_owned() + docstring.contents,
-            docstring.range(),
-        )));
+        if !docstring.leading_quote().contains(['u', 'U']) {
+            diagnostic.set_fix(Fix::unsafe_edit(Edit::range_replacement(
+                "r".to_owned() + docstring.contents,
+                docstring.range(),
+            )));
+        }
 
         checker.diagnostics.push(diagnostic);
     }

crates/ruff_linter/src/rules/pydocstyle/snapshots/ruff_linter__rules__pydocstyle__tests__D301_D301.py.snap

@@ -17,4 +17,12 @@ D301.py:2:5: D301 [*] Use `r"""` if any backslashes in a docstring
 4 4 | 
 5 5 | def double_quotes_backslash_raw():
 
+D301.py:37:5: D301 Use `r"""` if any backslashes in a docstring
+   |
+36 | def shouldnt_add_raw_here2():
+37 |     u"Sum\\mary."
+   |     ^^^^^^^^^^^^^ D301
+   |
+   = help: Add `r` prefix
+
 

crates/ruff_linter/src/rules/pyflakes/mod.rs

@@ -26,6 +26,7 @@ mod tests {
     use crate::linter::{check_path, LinterResult};
     use crate::registry::{AsRule, Linter, Rule};
     use crate::rules::pyflakes;
+    use crate::settings::types::PreviewMode;
     use crate::settings::{flags, LinterSettings};
     use crate::source_kind::SourceKind;
     use crate::test::{test_path, test_snippet};
@@ -145,6 +146,7 @@ mod tests {
     #[test_case(Rule::UnusedVariable, Path::new("F841_1.py"))]
     #[test_case(Rule::UnusedVariable, Path::new("F841_2.py"))]
     #[test_case(Rule::UnusedVariable, Path::new("F841_3.py"))]
+    #[test_case(Rule::UnusedVariable, Path::new("F841_4.py"))]
     #[test_case(Rule::UnusedAnnotation, Path::new("F842.py"))]
     #[test_case(Rule::RaiseNotImplemented, Path::new("F901.py"))]
     fn rules(rule_code: Rule, path: &Path) -> Result<()> {
@@ -157,6 +159,24 @@ mod tests {
         Ok(())
     }
 
+    #[test_case(Rule::UnusedVariable, Path::new("F841_4.py"))]
+    fn preview_rules(rule_code: Rule, path: &Path) -> Result<()> {
+        let snapshot = format!(
+            "preview__{}_{}",
+            rule_code.noqa_code(),
+            path.to_string_lossy()
+        );
+        let diagnostics = test_path(
+            Path::new("pyflakes").join(path).as_path(),
+            &LinterSettings {
+                preview: PreviewMode::Enabled,
+                ..LinterSettings::for_rule(rule_code)
+            },
+        )?;
+        assert_messages!(snapshot, diagnostics);
+        Ok(())
+    }
+
     #[test]
     fn f841_dummy_variable_rgx() -> Result<()> {
         let diagnostics = test_path(
@@ -1126,7 +1146,8 @@ mod tests {
 
     #[test]
     fn used_as_star_unpack() {
-        // Star names in unpack are used if RHS is not a tuple/list literal.
+        // In stable, starred names in unpack are used if RHS is not a tuple/list literal.
+        // In preview, these should be marked as unused.
         flakes(
             r#"
         def f():

crates/ruff_linter/src/rules/pyflakes/rules/unused_variable.rs

@@ -12,6 +12,7 @@ use ruff_text_size::{Ranged, TextRange, TextSize};
 
 use crate::checkers::ast::Checker;
 use crate::fix::edits::delete_stmt;
+use crate::settings::types::PreviewMode;
 
 /// ## What it does
 /// Checks for the presence of unused variables in function scopes.
@@ -24,6 +25,9 @@ use crate::fix::edits::delete_stmt;
 /// prefixed with an underscore, or some other value that adheres to the
 /// [`dummy-variable-rgx`] pattern.
 ///
+/// Under [preview mode](https://docs.astral.sh/ruff/preview), this rule also
+/// triggers on unused unpacked assignments (for example, `x, y = foo()`).
+///
 /// ## Example
 /// ```python
 /// def foo():
@@ -318,7 +322,10 @@ pub(crate) fn unused_variable(checker: &Checker, scope: &Scope, diagnostics: &mu
         .bindings()
         .map(|(name, binding_id)| (name, checker.semantic().binding(binding_id)))
         .filter_map(|(name, binding)| {
-            if (binding.kind.is_assignment() || binding.kind.is_named_expr_assignment())
+            if (binding.kind.is_assignment()
+                || binding.kind.is_named_expr_assignment()
+                || (matches!(checker.settings.preview, PreviewMode::Enabled)
+                    && binding.kind.is_unpacked_assignment()))
                 && !binding.is_nonlocal()
                 && !binding.is_global()
                 && !binding.is_used()

crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__F841_F841_1.py.snap

@@ -20,7 +20,7 @@ F841_1.py:6:8: F841 Local variable `y` is assigned to but never used
 F841_1.py:16:14: F841 [*] Local variable `coords` is assigned to but never used
    |
 15 | def f():
-16 |     (x, y) = coords = 1, 2  # this triggers F841 on coords
+16 |     (x, y) = coords = 1, 2
    |              ^^^^^^ F841
    |
    = help: Remove assignment to unused variable `coords`
@@ -29,8 +29,8 @@ F841_1.py:16:14: F841 [*] Local variable `coords` is assigned to but never used
 13 13 | 
 14 14 | 
 15 15 | def f():
-16    |-    (x, y) = coords = 1, 2  # this triggers F841 on coords
-   16 |+    (x, y) = 1, 2  # this triggers F841 on coords
+16    |-    (x, y) = coords = 1, 2
+   16 |+    (x, y) = 1, 2
 17 17 | 
 18 18 | 
 19 19 | def f():
@@ -38,7 +38,7 @@ F841_1.py:16:14: F841 [*] Local variable `coords` is assigned to but never used
 F841_1.py:20:5: F841 [*] Local variable `coords` is assigned to but never used
    |
 19 | def f():
-20 |     coords = (x, y) = 1, 2  # this triggers F841 on coords
+20 |     coords = (x, y) = 1, 2
    |     ^^^^^^ F841
    |
    = help: Remove assignment to unused variable `coords`
@@ -47,8 +47,8 @@ F841_1.py:20:5: F841 [*] Local variable `coords` is assigned to but never used
 17 17 | 
 18 18 | 
 19 19 | def f():
-20    |-    coords = (x, y) = 1, 2  # this triggers F841 on coords
-   20 |+    (x, y) = 1, 2  # this triggers F841 on coords
+20    |-    coords = (x, y) = 1, 2
+   20 |+    (x, y) = 1, 2
 21 21 | 
 22 22 | 
 23 23 | def f():

crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__F841_F841_4.py.snap

@@ -0,0 +1,23 @@
+---
+source: crates/ruff_linter/src/rules/pyflakes/mod.rs
+---
+F841_4.py:12:5: F841 [*] Local variable `a` is assigned to but never used
+   |
+11 | def bar():
+12 |     a = foo()
+   |     ^ F841
+13 |     b, c = foo()
+   |
+   = help: Remove assignment to unused variable `a`
+
+ℹ Suggested fix
+9  9  | 
+10 10 | 
+11 11 | def bar():
+12    |-    a = foo()
+   12 |+    foo()
+13 13 |     b, c = foo()
+14 14 | 
+15 15 | 
+
+

crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__preview__F841_F841_4.py.snap

@@ -0,0 +1,41 @@
+---
+source: crates/ruff_linter/src/rules/pyflakes/mod.rs
+---
+F841_4.py:12:5: F841 [*] Local variable `a` is assigned to but never used
+   |
+11 | def bar():
+12 |     a = foo()
+   |     ^ F841
+13 |     b, c = foo()
+   |
+   = help: Remove assignment to unused variable `a`
+
+ℹ Suggested fix
+9  9  | 
+10 10 | 
+11 11 | def bar():
+12    |-    a = foo()
+   12 |+    foo()
+13 13 |     b, c = foo()
+14 14 | 
+15 15 | 
+
+F841_4.py:13:5: F841 Local variable `b` is assigned to but never used
+   |
+11 | def bar():
+12 |     a = foo()
+13 |     b, c = foo()
+   |     ^ F841
+   |
+   = help: Remove assignment to unused variable `b`
+
+F841_4.py:13:8: F841 Local variable `c` is assigned to but never used
+   |
+11 | def bar():
+12 |     a = foo()
+13 |     b, c = foo()
+   |        ^ F841
+   |
+   = help: Remove assignment to unused variable `c`
+
+

crates/ruff_linter/src/rules/pyupgrade/rules/use_pep695_type_alias.rs

@@ -138,7 +138,7 @@ pub(crate) fn non_pep695_type_alias(checker: &mut Checker, stmt: &StmtAnnAssign)
         stmt.range(),
     );
 
-    // The fix is only safe in a type stub because new-style aliases have different runtime  behavior
+    // The fix is only safe in a type stub because new-style aliases have different runtime behavior
     // See https://github.com/astral-sh/ruff/issues/6434
     let fix = if checker.source_type.is_stub() {
         Fix::safe_edit(edit)

crates/ruff_linter/src/rules/refurb/helpers.rs

@@ -34,3 +34,30 @@ pub(super) fn generate_method_call(name: &str, method: &str, generator: Generato
     };
     generator.stmt(&stmt.into())
 }
+
+/// Format a code snippet comparing `name` to `None` (e.g., `name is None`).
+pub(super) fn generate_none_identity_comparison(
+    name: &str,
+    negate: bool,
+    generator: Generator,
+) -> String {
+    // Construct `name`.
+    let var = ast::ExprName {
+        id: name.to_string(),
+        ctx: ast::ExprContext::Load,
+        range: TextRange::default(),
+    };
+    // Construct `name is None` or `name is not None`.
+    let op = if negate {
+        ast::CmpOp::IsNot
+    } else {
+        ast::CmpOp::Is
+    };
+    let compare = ast::ExprCompare {
+        left: Box::new(var.into()),
+        ops: vec![op],
+        comparators: vec![ast::Expr::NoneLiteral(ast::ExprNoneLiteral::default())],
+        range: TextRange::default(),
+    };
+    generator.expr(&compare.into())
+}

crates/ruff_linter/src/rules/refurb/mod.rs

@@ -25,6 +25,7 @@ mod tests {
     #[test_case(Rule::ImplicitCwd, Path::new("FURB177.py"))]
     #[test_case(Rule::SingleItemMembershipTest, Path::new("FURB171.py"))]
     #[test_case(Rule::IsinstanceTypeNone, Path::new("FURB168.py"))]
+    #[test_case(Rule::TypeNoneComparison, Path::new("FURB169.py"))]
     fn rules(rule_code: Rule, path: &Path) -> Result<()> {
         let snapshot = format!("{}_{}", rule_code.noqa_code(), path.to_string_lossy());
         let diagnostics = test_path(

crates/ruff_linter/src/rules/refurb/rules/check_and_remove_from_set.rs

@@ -97,9 +97,9 @@ pub(crate) fn check_and_remove_from_set(checker: &mut Checker, if_stmt: &ast::St
     // Check if what we assume is set is indeed a set.
     if !checker
         .semantic()
-        .resolve_name(check_set)
-        .map(|binding_id| checker.semantic().binding(binding_id))
-        .map_or(false, |binding| is_set(binding, checker.semantic()))
+        .only_binding(check_set)
+        .map(|id| checker.semantic().binding(id))
+        .is_some_and(|binding| is_set(binding, checker.semantic()))
     {
         return;
     };

crates/ruff_linter/src/rules/refurb/rules/delete_full_slice.rs

@@ -2,7 +2,7 @@ use ruff_diagnostics::{Diagnostic, Edit, Fix, FixAvailability, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::{self as ast, Expr};
 use ruff_python_semantic::analyze::typing::{is_dict, is_list};
-use ruff_python_semantic::{Binding, SemanticModel};
+use ruff_python_semantic::SemanticModel;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -70,7 +70,7 @@ pub(crate) fn delete_full_slice(checker: &mut Checker, delete: &ast::StmtDelete)
 
         // Fix is only supported for single-target deletions.
         if delete.targets.len() == 1 {
-            let replacement = generate_method_call(name, "clear", checker.generator());
+            let replacement = generate_method_call(&name.id, "clear", checker.generator());
             diagnostic.set_fix(Fix::unsafe_edit(Edit::replacement(
                 replacement,
                 delete.start(),
@@ -83,7 +83,7 @@ pub(crate) fn delete_full_slice(checker: &mut Checker, delete: &ast::StmtDelete)
 }
 
 /// Match `del expr[:]` where `expr` is a list or a dict.
-fn match_full_slice<'a>(expr: &'a Expr, semantic: &SemanticModel) -> Option<&'a str> {
+fn match_full_slice<'a>(expr: &'a Expr, semantic: &SemanticModel) -> Option<&'a ast::ExprName> {
     // Check that it is `del expr[...]`.
     let subscript = expr.as_subscript_expr()?;
 
@@ -100,22 +100,9 @@ fn match_full_slice<'a>(expr: &'a Expr, semantic: &SemanticModel) -> Option<&'a
         return None;
     }
 
-    // Check that it is del var[:]
-    let ast::ExprName { id: name, .. } = subscript.value.as_name_expr()?;
-
-    // Let's find definition for var
-    let scope = semantic.current_scope();
-    let bindings: Vec<&Binding> = scope
-        .get_all(name)
-        .map(|binding_id| semantic.binding(binding_id))
-        .collect();
-
-    // NOTE: Maybe it is too strict of a limitation, but it seems reasonable.
-    let [binding] = bindings.as_slice() else {
-        return None;
-    };
-
     // It should only apply to variables that are known to be lists or dicts.
+    let name = subscript.value.as_name_expr()?;
+    let binding = semantic.binding(semantic.only_binding(name)?);
     if !(is_dict(binding, semantic) || is_list(binding, semantic)) {
         return None;
     }

crates/ruff_linter/src/rules/refurb/rules/isinstance_type_none.rs

@@ -2,11 +2,11 @@ use ruff_diagnostics::{Diagnostic, Edit, Fix, FixAvailability, Violation};
 use ruff_python_ast::{self as ast, Expr, Operator};
 
 use ruff_macros::{derive_message_formats, violation};
-use ruff_python_codegen::Generator;
-use ruff_text_size::{Ranged, TextRange};
+use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
 use crate::fix::edits::pad;
+use crate::rules::refurb::helpers::generate_none_identity_comparison;
 
 /// ## What it does
 /// Checks for uses of `isinstance` that check if an object is of type `None`.
@@ -69,7 +69,8 @@ pub(crate) fn isinstance_type_none(checker: &mut Checker, call: &ast::ExprCall)
             return;
         };
         let mut diagnostic = Diagnostic::new(IsinstanceTypeNone, call.range());
-        let replacement = generate_replacement(object_name, checker.generator());
+        let replacement =
+            generate_none_identity_comparison(object_name, false, checker.generator());
         diagnostic.set_fix(Fix::safe_edit(Edit::range_replacement(
             pad(replacement, call.range(), checker.locator()),
             call.range(),
@@ -117,21 +118,3 @@ fn is_none(expr: &Expr) -> bool {
     }
     inner(expr, false)
 }
-
-/// Format a code snippet comparing `name` to `None` (e.g., `name is None`).
-fn generate_replacement(name: &str, generator: Generator) -> String {
-    // Construct `name`.
-    let var = ast::ExprName {
-        id: name.to_string(),
-        ctx: ast::ExprContext::Load,
-        range: TextRange::default(),
-    };
-    // Construct `name is None`.
-    let compare = ast::ExprCompare {
-        left: Box::new(var.into()),
-        ops: vec![ast::CmpOp::Is],
-        comparators: vec![ast::Expr::NoneLiteral(ast::ExprNoneLiteral::default())],
-        range: TextRange::default(),
-    };
-    generator.expr(&compare.into())
-}

crates/ruff_linter/src/rules/refurb/rules/mod.rs

@@ -8,6 +8,7 @@ pub(crate) use reimplemented_starmap::*;
 pub(crate) use repeated_append::*;
 pub(crate) use single_item_membership_test::*;
 pub(crate) use slice_copy::*;
+pub(crate) use type_none_comparison::*;
 pub(crate) use unnecessary_enumerate::*;
 
 mod check_and_remove_from_set;
@@ -20,4 +21,5 @@ mod reimplemented_starmap;
 mod repeated_append;
 mod single_item_membership_test;
 mod slice_copy;
+mod type_none_comparison;
 mod unnecessary_enumerate;

crates/ruff_linter/src/rules/refurb/rules/repeated_append.rs

@@ -76,7 +76,7 @@ impl Violation for RepeatedAppend {
 
 /// FURB113
 pub(crate) fn repeated_append(checker: &mut Checker, stmt: &Stmt) {
-    let Some(appends) = match_consecutive_appends(checker.semantic(), stmt) else {
+    let Some(appends) = match_consecutive_appends(stmt, checker.semantic()) else {
         return;
     };
 
@@ -163,8 +163,8 @@ impl Ranged for AppendGroup<'_> {
 
 /// Match consecutive calls to `append` on list variables starting from the given statement.
 fn match_consecutive_appends<'a>(
-    semantic: &'a SemanticModel,
     stmt: &'a Stmt,
+    semantic: &'a SemanticModel,
 ) -> Option<Vec<Append<'a>>> {
     // Match the current statement, to see if it's an append.
     let append = match_append(semantic, stmt)?;

crates/ruff_linter/src/rules/refurb/rules/type_none_comparison.rs

@@ -0,0 +1,153 @@
+use ruff_diagnostics::{Diagnostic, Edit, Fix, FixAvailability, Violation};
+use ruff_macros::{derive_message_formats, violation};
+use ruff_python_ast::{self as ast, CmpOp, Expr};
+use ruff_python_semantic::SemanticModel;
+use ruff_text_size::Ranged;
+
+use crate::checkers::ast::Checker;
+use crate::fix::edits::pad;
+use crate::rules::refurb::helpers::generate_none_identity_comparison;
+
+/// ## What it does
+/// Checks for uses of `type` that compare the type of an object to the type of
+/// `None`.
+///
+/// ## Why is this bad?
+/// There is only ever one instance of `None`, so it is more efficient and
+/// readable to use the `is` operator to check if an object is `None`.
+///
+/// ## Example
+/// ```python
+/// type(obj) is type(None)
+/// ```
+///
+/// Use instead:
+/// ```python
+/// obj is None
+/// ```
+///
+/// ## References
+/// - [Python documentation: `isinstance`](https://docs.python.org/3/library/functions.html#isinstance)
+/// - [Python documentation: `None`](https://docs.python.org/3/library/constants.html#None)
+/// - [Python documentation: `type`](https://docs.python.org/3/library/functions.html#type)
+/// - [Python documentation: Identity comparisons](https://docs.python.org/3/reference/expressions.html#is-not)
+#[violation]
+pub struct TypeNoneComparison {
+    object: String,
+    comparison: Comparison,
+}
+
+impl Violation for TypeNoneComparison {
+    const FIX_AVAILABILITY: FixAvailability = FixAvailability::Sometimes;
+
+    #[derive_message_formats]
+    fn message(&self) -> String {
+        let TypeNoneComparison { object, .. } = self;
+        format!("Compare the identities of `{object}` and `None` instead of their respective types")
+    }
+
+    fn fix_title(&self) -> Option<String> {
+        let TypeNoneComparison { object, comparison } = self;
+        match comparison {
+            Comparison::Is | Comparison::Eq => Some(format!("Replace with `{object} is None`")),
+            Comparison::IsNot | Comparison::NotEq => {
+                Some(format!("Replace with `{object} is not None`"))
+            }
+        }
+    }
+}
+
+/// FURB169
+pub(crate) fn type_none_comparison(checker: &mut Checker, compare: &ast::ExprCompare) {
+    let ([op], [right]) = (compare.ops.as_slice(), compare.comparators.as_slice()) else {
+        return;
+    };
+
+    // Ensure that the comparison is an identity or equality test.
+    let comparison = match op {
+        CmpOp::Is => Comparison::Is,
+        CmpOp::IsNot => Comparison::IsNot,
+        CmpOp::Eq => Comparison::Eq,
+        CmpOp::NotEq => Comparison::NotEq,
+        _ => return,
+    };
+
+    // Get the objects whose types are being compared.
+    let Some(left_arg) = type_call_arg(&compare.left, checker.semantic()) else {
+        return;
+    };
+    let Some(right_arg) = type_call_arg(right, checker.semantic()) else {
+        return;
+    };
+
+    // If one of the objects is `None`, get the other object; else, return.
+    let other_arg = match (
+        left_arg.is_none_literal_expr(),
+        right_arg.is_none_literal_expr(),
+    ) {
+        (true, false) => right_arg,
+        (false, true) => left_arg,
+        // If both are `None`, just pick one.
+        (true, true) => left_arg,
+        _ => return,
+    };
+
+    // Get the name of the other object (or `None` if both were `None`).
+    let other_arg_name = match other_arg {
+        Expr::Name(ast::ExprName { id, .. }) => id.as_str(),
+        Expr::NoneLiteral { .. } => "None",
+        _ => return,
+    };
+
+    let mut diagnostic = Diagnostic::new(
+        TypeNoneComparison {
+            object: other_arg_name.to_string(),
+            comparison,
+        },
+        compare.range(),
+    );
+    diagnostic.set_fix(Fix::safe_edit(Edit::range_replacement(
+        pad(
+            match comparison {
+                Comparison::Is | Comparison::Eq => {
+                    generate_none_identity_comparison(other_arg_name, false, checker.generator())
+                }
+                Comparison::IsNot | Comparison::NotEq => {
+                    generate_none_identity_comparison(other_arg_name, true, checker.generator())
+                }
+            },
+            compare.range(),
+            checker.locator(),
+        ),
+        compare.range(),
+    )));
+    checker.diagnostics.push(diagnostic);
+}
+
+/// Returns the object passed to the function, if the expression is a call to
+/// `type` with a single argument.
+fn type_call_arg<'a>(expr: &'a Expr, semantic: &'a SemanticModel) -> Option<&'a Expr> {
+    // The expression must be a single-argument call to `type`.
+    let ast::ExprCall {
+        func, arguments, ..
+    } = expr.as_call_expr()?;
+    if arguments.len() != 1 {
+        return None;
+    }
+
+    // The function itself must be the builtin `type`.
+    let ast::ExprName { id, .. } = func.as_name_expr()?;
+    if id.as_str() != "type" || !semantic.is_builtin(id) {
+        return None;
+    }
+
+    arguments.find_positional(0)
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+enum Comparison {
+    Is,
+    IsNot,
+    Eq,
+    NotEq,
+}

crates/ruff_linter/src/rules/refurb/rules/unnecessary_enumerate.rs

@@ -6,7 +6,7 @@ use ruff_python_ast as ast;
 use ruff_python_ast::{Arguments, Expr, Int};
 use ruff_python_codegen::Generator;
 use ruff_python_semantic::analyze::typing::{is_dict, is_list, is_set, is_tuple};
-use ruff_python_semantic::Binding;
+
 use ruff_text_size::{Ranged, TextRange};
 
 use crate::checkers::ast::Checker;
@@ -114,7 +114,7 @@ pub(crate) fn unnecessary_enumerate(checker: &mut Checker, stmt_for: &ast::StmtF
     };
 
     // Get the first argument, which is the sequence to iterate over.
-    let Some(Expr::Name(ast::ExprName { id: sequence, .. })) = arguments.args.first() else {
+    let Some(Expr::Name(sequence)) = arguments.args.first() else {
         return;
     };
 
@@ -138,7 +138,8 @@ pub(crate) fn unnecessary_enumerate(checker: &mut Checker, stmt_for: &ast::StmtF
             );
 
             // The index is unused, so replace with `for value in sequence`.
-            let replace_iter = Edit::range_replacement(sequence.into(), stmt_for.iter.range());
+            let replace_iter =
+                Edit::range_replacement(sequence.id.to_string(), stmt_for.iter.range());
             let replace_target = Edit::range_replacement(
                 pad(
                     checker.locator().slice(value).to_string(),
@@ -154,12 +155,11 @@ pub(crate) fn unnecessary_enumerate(checker: &mut Checker, stmt_for: &ast::StmtF
         (false, true) => {
             // Ensure the sequence object works with `len`. If it doesn't, the
             // fix is unclear.
-            let scope = checker.semantic().current_scope();
-            let bindings: Vec<&Binding> = scope
-                .get_all(sequence)
-                .map(|binding_id| checker.semantic().binding(binding_id))
-                .collect();
-            let [binding] = bindings.as_slice() else {
+            let Some(binding) = checker
+                .semantic()
+                .only_binding(sequence)
+                .map(|id| checker.semantic().binding(id))
+            else {
                 return;
             };
             // This will lead to a lot of false negatives, but it is the best
@@ -193,7 +193,7 @@ pub(crate) fn unnecessary_enumerate(checker: &mut Checker, stmt_for: &ast::StmtF
                     )
                 }) {
                     let replace_iter = Edit::range_replacement(
-                        generate_range_len_call(sequence, checker.generator()),
+                        generate_range_len_call(&sequence.id, checker.generator()),
                         stmt_for.iter.range(),
                     );
 

crates/ruff_linter/src/rules/refurb/snapshots/ruff_linter__rules__refurb__tests__FURB131_FURB131.py.snap

@@ -127,6 +127,27 @@ FURB131.py:43:5: FURB131 [*] Prefer `clear` over deleting a full slice
    43 |+    x.clear()
 44 44 | 
 45 45 | 
-46 46 | # these should not
+46 46 | def yes_five(x: Dict[int, str]):
+
+FURB131.py:48:5: FURB131 [*] Prefer `clear` over deleting a full slice
+   |
+46 | def yes_five(x: Dict[int, str]):
+47 |     # FURB131
+48 |     del x[:]
+   |     ^^^^^^^^ FURB131
+49 | 
+50 |     x = 1
+   |
+   = help: Replace with `clear()`
+
+ℹ Suggested fix
+45 45 | 
+46 46 | def yes_five(x: Dict[int, str]):
+47 47 |     # FURB131
+48    |-    del x[:]
+   48 |+    x.clear()
+49 49 | 
+50 50 |     x = 1
+51 51 | 
 
 

crates/ruff_linter/src/rules/refurb/snapshots/ruff_linter__rules__refurb__tests__FURB169_FURB169.py.snap

@@ -0,0 +1,256 @@
+---
+source: crates/ruff_linter/src/rules/refurb/mod.rs
+---
+FURB169.py:5:1: FURB169 [*] Compare the identities of `foo` and `None` instead of their respective types
+  |
+3 | # Error.
+4 | 
+5 | type(foo) is type(None)
+  | ^^^^^^^^^^^^^^^^^^^^^^^ FURB169
+6 | 
+7 | type(None) is type(foo)
+  |
+  = help: Replace with `foo is None`
+
+ℹ Fix
+2 2 | 
+3 3 | # Error.
+4 4 | 
+5   |-type(foo) is type(None)
+  5 |+foo is None
+6 6 | 
+7 7 | type(None) is type(foo)
+8 8 | 
+
+FURB169.py:7:1: FURB169 [*] Compare the identities of `foo` and `None` instead of their respective types
+  |
+5 | type(foo) is type(None)
+6 | 
+7 | type(None) is type(foo)
+  | ^^^^^^^^^^^^^^^^^^^^^^^ FURB169
+8 | 
+9 | type(None) is type(None)
+  |
+  = help: Replace with `foo is None`
+
+ℹ Fix
+4 4 | 
+5 5 | type(foo) is type(None)
+6 6 | 
+7   |-type(None) is type(foo)
+  7 |+foo is None
+8 8 | 
+9 9 | type(None) is type(None)
+10 10 | 
+
+FURB169.py:9:1: FURB169 [*] Compare the identities of `None` and `None` instead of their respective types
+   |
+ 7 | type(None) is type(foo)
+ 8 | 
+ 9 | type(None) is type(None)
+   | ^^^^^^^^^^^^^^^^^^^^^^^^ FURB169
+10 | 
+11 | type(foo) is not type(None)
+   |
+   = help: Replace with `None is None`
+
+ℹ Fix
+6  6  | 
+7  7  | type(None) is type(foo)
+8  8  | 
+9     |-type(None) is type(None)
+   9  |+None is None
+10 10 | 
+11 11 | type(foo) is not type(None)
+12 12 | 
+
+FURB169.py:11:1: FURB169 [*] Compare the identities of `foo` and `None` instead of their respective types
+   |
+ 9 | type(None) is type(None)
+10 | 
+11 | type(foo) is not type(None)
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ FURB169
+12 | 
+13 | type(None) is not type(foo)
+   |
+   = help: Replace with `foo is not None`
+
+ℹ Fix
+8  8  | 
+9  9  | type(None) is type(None)
+10 10 | 
+11    |-type(foo) is not type(None)
+   11 |+foo is not None
+12 12 | 
+13 13 | type(None) is not type(foo)
+14 14 | 
+
+FURB169.py:13:1: FURB169 [*] Compare the identities of `foo` and `None` instead of their respective types
+   |
+11 | type(foo) is not type(None)
+12 | 
+13 | type(None) is not type(foo)
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ FURB169
+14 | 
+15 | type(None) is not type(None)
+   |
+   = help: Replace with `foo is not None`
+
+ℹ Fix
+10 10 | 
+11 11 | type(foo) is not type(None)
+12 12 | 
+13    |-type(None) is not type(foo)
+   13 |+foo is not None
+14 14 | 
+15 15 | type(None) is not type(None)
+16 16 | 
+
+FURB169.py:15:1: FURB169 [*] Compare the identities of `None` and `None` instead of their respective types
+   |
+13 | type(None) is not type(foo)
+14 | 
+15 | type(None) is not type(None)
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ FURB169
+16 | 
+17 | type(foo) == type(None)
+   |
+   = help: Replace with `None is not None`
+
+ℹ Fix
+12 12 | 
+13 13 | type(None) is not type(foo)
+14 14 | 
+15    |-type(None) is not type(None)
+   15 |+None is not None
+16 16 | 
+17 17 | type(foo) == type(None)
+18 18 | 
+
+FURB169.py:17:1: FURB169 [*] Compare the identities of `foo` and `None` instead of their respective types
+   |
+15 | type(None) is not type(None)
+16 | 
+17 | type(foo) == type(None)
+   | ^^^^^^^^^^^^^^^^^^^^^^^ FURB169
+18 | 
+19 | type(None) == type(foo)
+   |
+   = help: Replace with `foo is None`
+
+ℹ Fix
+14 14 | 
+15 15 | type(None) is not type(None)
+16 16 | 
+17    |-type(foo) == type(None)
+   17 |+foo is None
+18 18 | 
+19 19 | type(None) == type(foo)
+20 20 | 
+
+FURB169.py:19:1: FURB169 [*] Compare the identities of `foo` and `None` instead of their respective types
+   |
+17 | type(foo) == type(None)
+18 | 
+19 | type(None) == type(foo)
+   | ^^^^^^^^^^^^^^^^^^^^^^^ FURB169
+20 | 
+21 | type(None) == type(None)
+   |
+   = help: Replace with `foo is None`
+
+ℹ Fix
+16 16 | 
+17 17 | type(foo) == type(None)
+18 18 | 
+19    |-type(None) == type(foo)
+   19 |+foo is None
+20 20 | 
+21 21 | type(None) == type(None)
+22 22 | 
+
+FURB169.py:21:1: FURB169 [*] Compare the identities of `None` and `None` instead of their respective types
+   |
+19 | type(None) == type(foo)
+20 | 
+21 | type(None) == type(None)
+   | ^^^^^^^^^^^^^^^^^^^^^^^^ FURB169
+22 | 
+23 | type(foo) != type(None)
+   |
+   = help: Replace with `None is None`
+
+ℹ Fix
+18 18 | 
+19 19 | type(None) == type(foo)
+20 20 | 
+21    |-type(None) == type(None)
+   21 |+None is None
+22 22 | 
+23 23 | type(foo) != type(None)
+24 24 | 
+
+FURB169.py:23:1: FURB169 [*] Compare the identities of `foo` and `None` instead of their respective types
+   |
+21 | type(None) == type(None)
+22 | 
+23 | type(foo) != type(None)
+   | ^^^^^^^^^^^^^^^^^^^^^^^ FURB169
+24 | 
+25 | type(None) != type(foo)
+   |
+   = help: Replace with `foo is not None`
+
+ℹ Fix
+20 20 | 
+21 21 | type(None) == type(None)
+22 22 | 
+23    |-type(foo) != type(None)
+   23 |+foo is not None
+24 24 | 
+25 25 | type(None) != type(foo)
+26 26 | 
+
+FURB169.py:25:1: FURB169 [*] Compare the identities of `foo` and `None` instead of their respective types
+   |
+23 | type(foo) != type(None)
+24 | 
+25 | type(None) != type(foo)
+   | ^^^^^^^^^^^^^^^^^^^^^^^ FURB169
+26 | 
+27 | type(None) != type(None)
+   |
+   = help: Replace with `foo is not None`
+
+ℹ Fix
+22 22 | 
+23 23 | type(foo) != type(None)
+24 24 | 
+25    |-type(None) != type(foo)
+   25 |+foo is not None
+26 26 | 
+27 27 | type(None) != type(None)
+28 28 | 
+
+FURB169.py:27:1: FURB169 [*] Compare the identities of `None` and `None` instead of their respective types
+   |
+25 | type(None) != type(foo)
+26 | 
+27 | type(None) != type(None)
+   | ^^^^^^^^^^^^^^^^^^^^^^^^ FURB169
+28 | 
+29 | # Ok.
+   |
+   = help: Replace with `None is not None`
+
+ℹ Fix
+24 24 | 
+25 25 | type(None) != type(foo)
+26 26 | 
+27    |-type(None) != type(None)
+   27 |+None is not None
+28 28 | 
+29 29 | # Ok.
+30 30 | 
+
+

crates/ruff_linter/src/rules/ruff/rules/quadratic_list_summation.rs

@@ -25,7 +25,7 @@ use crate::importer::ImportRequest;
 /// lists:
 ///
 /// - `functools.reduce(operator.iconcat, lists, [])`
-/// - `list(itertools.chain.from_iterable(lists)`
+/// - `list(itertools.chain.from_iterable(lists))`
 /// - `[item for sublist in lists for item in sublist]`
 ///
 /// ## Example

crates/ruff_linter/src/rules/ruff/rules/unnecessary_iterable_allocation_for_first_element.rs

@@ -20,15 +20,6 @@ use crate::fix::snippet::SourceCodeSnippet;
 /// element of the collection, you can use `next(...)` or `next(iter(...)` to
 /// lazily fetch the first element.
 ///
-/// Note that migrating from `list(...)[0]` to `next(iter(...))` can change
-/// the behavior of your program in two ways:
-///
-/// 1. First, `list(...)` will eagerly evaluate the entire collection, while
-///    `next(iter(...))` will only evaluate the first element. As such, any
-///    side effects that occur during iteration will be delayed.
-/// 2. Second, `list(...)[0]` will raise `IndexError` if the collection is
-///    empty, while `next(iter(...))` will raise `StopIteration`.
-///
 /// ## Example
 /// ```python
 /// head = list(x)[0]
@@ -41,6 +32,16 @@ use crate::fix::snippet::SourceCodeSnippet;
 /// head = next(x * x for x in range(10))
 /// ```
 ///
+/// ## Fix safety
+/// This rule's fix is marked as unsafe, as migrating from `list(...)[0]` to
+/// `next(iter(...))` can change the behavior of your program in two ways:
+///
+/// 1. First, `list(...)` will eagerly evaluate the entire collection, while
+///    `next(iter(...))` will only evaluate the first element. As such, any
+///    side effects that occur during iteration will be delayed.
+/// 2. Second, `list(...)[0]` will raise `IndexError` if the collection is
+///    empty, while `next(iter(...))` will raise `StopIteration`.
+///
 /// ## References
 /// - [Iterators and Iterables in Python: Run Efficient Iterations](https://realpython.com/python-iterators-iterables/#when-to-use-an-iterator-in-python)
 #[violation]

crates/ruff_linter/src/rules/tryceratops/rules/verbose_raise.rs

@@ -31,6 +31,10 @@ use crate::checkers::ast::Checker;
 ///     except ValueError:
 ///         raise
 /// ```
+///
+/// ## Fix safety
+/// This rule's fix is marked as unsafe, as it doesn't properly handle bound
+/// exceptions that are shadowed between the `except` and `raise` statements.
 #[violation]
 pub struct VerboseRaise;
 

crates/ruff_python_ast/src/helpers.rs

@@ -10,6 +10,7 @@ use ruff_text_size::{Ranged, TextRange};
 use crate::call_path::CallPath;
 use crate::parenthesize::parenthesized_range;
 use crate::statement_visitor::{walk_body, walk_stmt, StatementVisitor};
+use crate::visitor::Visitor;
 use crate::AnyNodeRef;
 use crate::{
     self as ast, Arguments, CmpOp, ExceptHandler, Expr, MatchCase, Pattern, Stmt, TypeParam,
@@ -931,6 +932,29 @@ where
     }
 }
 
+/// A [`Visitor`] that detects the presence of `await` expressions in the current scope.
+#[derive(Debug, Default)]
+pub struct AwaitVisitor {
+    pub seen_await: bool,
+}
+
+impl Visitor<'_> for AwaitVisitor {
+    fn visit_stmt(&mut self, stmt: &Stmt) {
+        match stmt {
+            Stmt::FunctionDef(_) | Stmt::ClassDef(_) => (),
+            _ => crate::visitor::walk_stmt(self, stmt),
+        }
+    }
+
+    fn visit_expr(&mut self, expr: &Expr) {
+        if let Expr::Await(ast::ExprAwait { .. }) = expr {
+            self.seen_await = true;
+        } else {
+            crate::visitor::walk_expr(self, expr);
+        }
+    }
+}
+
 /// Return `true` if a `Stmt` is a docstring.
 pub fn is_docstring_stmt(stmt: &Stmt) -> bool {
     if let Stmt::Expr(ast::StmtExpr { value, range: _ }) = stmt {

crates/ruff_python_formatter/resources/test/fixtures/ruff/expression/lambda.py

@@ -203,3 +203,28 @@ lambda: ( # comment
     y:
     z
 )
+
+lambda self, araa, kkkwargs=aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa(*args, **kwargs), e=1, f=2, g=2: d
+
+# Regression tests for https://github.com/astral-sh/ruff/issues/8179
+def a():
+    return b(
+        c,
+        d,
+        e,
+        f=lambda self, *args, **kwargs: aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa(
+            *args, **kwargs
+        ),
+    )
+
+def a():
+    return b(
+        c,
+        d,
+        e,
+        f=lambda self, araa, kkkwargs,aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa,
+                 args,kwargs,
+                 e=1, f=2, g=2: d,
+        g = 10
+    )
+

crates/ruff_python_formatter/resources/test/fixtures/ruff/expression/yield.py

@@ -22,8 +22,6 @@ def foo():
         pass
 
 
-    (yield a, b) = (1, 2)
-
     # some comment
     for e in l : yield e # some comment
 

crates/ruff_python_formatter/src/other/parameters.rs

@@ -102,7 +102,15 @@ impl FormatNodeRule<Parameters> for FormatParameters {
             dangling.split_at(parenthesis_comments_end);
 
         let format_inner = format_with(|f: &mut PyFormatter| {
-            let separator = format_with(|f| write!(f, [token(","), soft_line_break_or_space()]));
+            let separator = format_with(|f: &mut PyFormatter| {
+                token(",").fmt(f)?;
+
+                if f.context().node_level().is_parenthesized() {
+                    soft_line_break_or_space().fmt(f)
+                } else {
+                    space().fmt(f)
+                }
+            });
             let mut joiner = f.join_with(separator);
             let mut last_node: Option<AnyNodeRef> = None;
 
@@ -232,8 +240,6 @@ impl FormatNodeRule<Parameters> for FormatParameters {
             Ok(())
         });
 
-        let mut f = WithNodeLevel::new(NodeLevel::ParenthesizedExpression, f);
-
         let num_parameters = posonlyargs.len()
             + args.len()
             + usize::from(vararg.is_some())
@@ -243,12 +249,14 @@ impl FormatNodeRule<Parameters> for FormatParameters {
         if self.parentheses == ParametersParentheses::Never {
             write!(f, [group(&format_inner), dangling_comments(dangling)])
         } else if num_parameters == 0 {
+            let mut f = WithNodeLevel::new(NodeLevel::ParenthesizedExpression, f);
             // No parameters, format any dangling comments between `()`
             write!(f, [empty_parenthesized("(", dangling, ")")])
         } else {
             // Intentionally avoid `parenthesized`, which groups the entire formatted contents.
             // We want parameters to be grouped alongside return types, one level up, so we
             // format them "inline" here.
+            let mut f = WithNodeLevel::new(NodeLevel::ParenthesizedExpression, f);
             write!(
                 f,
                 [

crates/ruff_python_formatter/tests/snapshots/format@expression__lambda.py.snap

@@ -209,6 +209,31 @@ lambda: ( # comment
     y:
     z
 )
+
+lambda self, araa, kkkwargs=aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa(*args, **kwargs), e=1, f=2, g=2: d
+
+# Regression tests for https://github.com/astral-sh/ruff/issues/8179
+def a():
+    return b(
+        c,
+        d,
+        e,
+        f=lambda self, *args, **kwargs: aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa(
+            *args, **kwargs
+        ),
+    )
+
+def a():
+    return b(
+        c,
+        d,
+        e,
+        f=lambda self, araa, kkkwargs,aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa,
+                 args,kwargs,
+                 e=1, f=2, g=2: d,
+        g = 10
+    )
+
 ```
 
 ## Output
@@ -413,6 +438,40 @@ lambda: (  # comment
     # comment
     y: z
 )
+
+lambda self, araa, kkkwargs=aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa(
+    *args, **kwargs
+), e=1, f=2, g=2: d
+
+
+# Regression tests for https://github.com/astral-sh/ruff/issues/8179
+def a():
+    return b(
+        c,
+        d,
+        e,
+        f=lambda self,
+        *args,
+        **kwargs: aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa(*args, **kwargs),
+    )
+
+
+def a():
+    return b(
+        c,
+        d,
+        e,
+        f=lambda self,
+        araa,
+        kkkwargs,
+        aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa,
+        args,
+        kwargs,
+        e=1,
+        f=2,
+        g=2: d,
+        g=10,
+    )
 ```
 
 

crates/ruff_python_formatter/tests/snapshots/format@expression__yield.py.snap

@@ -28,8 +28,6 @@ def foo():
         pass
 
 
-    (yield a, b) = (1, 2)
-
     # some comment
     for e in l : yield e # some comment
 
@@ -151,8 +149,6 @@ def foo():
         # comment
         pass
 
-    (yield a, b) = (1, 2)
-
     # some comment
     for e in l:
         yield e  # some comment

crates/ruff_python_parser/src/invalid.rs

@@ -0,0 +1,733 @@
+/*!
+Defines some helper routines for rejecting invalid Python programs.
+
+These routines are named in a way that supports qualified use. For example,
+`invalid::assignment_targets`.
+*/
+
+use {ruff_python_ast::Expr, ruff_text_size::TextSize};
+
+use crate::lexer::{LexicalError, LexicalErrorType};
+
+/// Returns an error for invalid assignment targets.
+///
+/// # Errors
+///
+/// This returns an error when any of the given expressions are themselves
+/// or contain an expression that is invalid on the left hand side of an
+/// assignment. For example, all literal expressions are invalid assignment
+/// targets.
+pub(crate) fn assignment_targets(targets: &[Expr]) -> Result<(), LexicalError> {
+    for t in targets {
+        assignment_target(t)?;
+    }
+    Ok(())
+}
+
+/// Returns an error if the given target is invalid for the left hand side of
+/// an assignment.
+///
+/// # Errors
+///
+/// This returns an error when the given expression is itself or contains an
+/// expression that is invalid on the left hand side of an assignment. For
+/// example, all literal expressions are invalid assignment targets.
+pub(crate) fn assignment_target(target: &Expr) -> Result<(), LexicalError> {
+    // Allowing a glob import here because of its limited scope.
+    #[allow(clippy::enum_glob_use)]
+    use self::Expr::*;
+
+    let err = |location: TextSize| -> LexicalError {
+        let error = LexicalErrorType::AssignmentError;
+        LexicalError { error, location }
+    };
+    match *target {
+        BoolOp(ref e) => Err(err(e.range.start())),
+        NamedExpr(ref e) => Err(err(e.range.start())),
+        BinOp(ref e) => Err(err(e.range.start())),
+        UnaryOp(ref e) => Err(err(e.range.start())),
+        Lambda(ref e) => Err(err(e.range.start())),
+        IfExp(ref e) => Err(err(e.range.start())),
+        Dict(ref e) => Err(err(e.range.start())),
+        Set(ref e) => Err(err(e.range.start())),
+        ListComp(ref e) => Err(err(e.range.start())),
+        SetComp(ref e) => Err(err(e.range.start())),
+        DictComp(ref e) => Err(err(e.range.start())),
+        GeneratorExp(ref e) => Err(err(e.range.start())),
+        Await(ref e) => Err(err(e.range.start())),
+        Yield(ref e) => Err(err(e.range.start())),
+        YieldFrom(ref e) => Err(err(e.range.start())),
+        Compare(ref e) => Err(err(e.range.start())),
+        Call(ref e) => Err(err(e.range.start())),
+        FormattedValue(ref e) => Err(err(e.range.start())),
+        // FString is recursive, but all its forms are invalid as an
+        // assignment target, so we can reject it without exploring it.
+        FString(ref e) => Err(err(e.range.start())),
+        StringLiteral(ref e) => Err(err(e.range.start())),
+        BytesLiteral(ref e) => Err(err(e.range.start())),
+        NumberLiteral(ref e) => Err(err(e.range.start())),
+        BooleanLiteral(ref e) => Err(err(e.range.start())),
+        NoneLiteral(ref e) => Err(err(e.range.start())),
+        EllipsisLiteral(ref e) => Err(err(e.range.start())),
+        // This isn't in the Python grammar but is Jupyter notebook specific.
+        // It seems like this should be an error. It does also seem like the
+        // parser prevents this from ever appearing as an assignment target
+        // anyway. ---AG
+        IpyEscapeCommand(ref e) => Err(err(e.range.start())),
+        // The only nested expressions allowed as an assignment target
+        // are star exprs, lists and tuples.
+        Starred(ref e) => assignment_target(&e.value),
+        List(ref e) => assignment_targets(&e.elts),
+        Tuple(ref e) => assignment_targets(&e.elts),
+        // Subscript is recursive and can be invalid, but aren't syntax errors.
+        // For example, `5[1] = 42` is a type error.
+        Subscript(_) => Ok(()),
+        // Similar to Subscript, e.g., `5[1:2] = [42]` is a type error.
+        Slice(_) => Ok(()),
+        // Similar to Subscript, e.g., `"foo".y = 42` is an attribute error.
+        Attribute(_) => Ok(()),
+        // These are always valid as assignment targets.
+        Name(_) => Ok(()),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::parse_suite;
+
+    // First we test, broadly, that various kinds of assignments are now
+    // rejected by the parser. e.g., `5 = 3`, `5 += 3`, `(5): int = 3`.
+
+    // Regression test: https://github.com/astral-sh/ruff/issues/6895
+    #[test]
+    fn err_literal_assignment() {
+        let ast = parse_suite(r"5 = 3", "<test>");
+        insta::assert_debug_snapshot!(ast, @r#"
+Err(
+    ParseError {
+        error: Lexical(
+            AssignmentError,
+        ),
+        offset: 0,
+        source_path: "<test>",
+    },
+)
+"#);
+    }
+
+    // This test previously passed before the assignment operator checking
+    // above, but we include it here for good measure.
+    #[test]
+    fn err_assignment_expr() {
+        let ast = parse_suite(r"(5 := 3)", "<test>");
+        insta::assert_debug_snapshot!(ast, @r#"
+Err(
+    ParseError {
+        error: UnrecognizedToken(
+            ColonEqual,
+            None,
+        ),
+        offset: 3,
+        source_path: "<test>",
+    },
+)
+"#);
+    }
+
+    #[test]
+    fn err_literal_augment_assignment() {
+        let ast = parse_suite(r"5 += 3", "<test>");
+        insta::assert_debug_snapshot!(ast, @r#"
+Err(
+    ParseError {
+        error: Lexical(
+            AssignmentError,
+        ),
+        offset: 0,
+        source_path: "<test>",
+    },
+)
+"#);
+    }
+
+    #[test]
+    fn err_literal_annotation_assignment() {
+        let ast = parse_suite(r"(5): int = 3", "<test>");
+        insta::assert_debug_snapshot!(ast, @r#"
+Err(
+    ParseError {
+        error: Lexical(
+            AssignmentError,
+        ),
+        offset: 1,
+        source_path: "<test>",
+    },
+)
+"#);
+    }
+
+    // Now we exhaustively test all possible cases where assignment can fail.
+
+    #[test]
+    fn err_bool_op() {
+        let ast = parse_suite(r"x or y = 42", "<test>");
+        insta::assert_debug_snapshot!(ast, @r#"
+Err(
+    ParseError {
+        error: Lexical(
+            AssignmentError,
+        ),
+        offset: 0,
+        source_path: "<test>",
+    },
+)
+"#);
+    }
+
+    #[test]
+    fn err_named_expr() {
+        let ast = parse_suite(r"(x := 5) = 42", "<test>");
+        insta::assert_debug_snapshot!(ast, @r#"
+Err(
+    ParseError {
+        error: Lexical(
+            AssignmentError,
+        ),
+        offset: 1,
+        source_path: "<test>",
+    },
+)
+"#);
+    }
+
+    #[test]
+    fn err_bin_op() {
+        let ast = parse_suite(r"x + y = 42", "<test>");
+        insta::assert_debug_snapshot!(ast, @r#"
+Err(
+    ParseError {
+        error: Lexical(
+            AssignmentError,
+        ),
+        offset: 0,
+        source_path: "<test>",
+    },
+)
+"#);
+    }
+
+    #[test]
+    fn err_unary_op() {
+        let ast = parse_suite(r"-x = 42", "<test>");
+        insta::assert_debug_snapshot!(ast, @r#"
+Err(
+    ParseError {
+        error: Lexical(
+            AssignmentError,
+        ),
+        offset: 0,
+        source_path: "<test>",
+    },
+)
+"#);
+    }
+
+    #[test]
+    fn err_lambda() {
+        let ast = parse_suite(r"(lambda _: 1) = 42", "<test>");
+        insta::assert_debug_snapshot!(ast, @r#"
+Err(
+    ParseError {
+        error: Lexical(
+            AssignmentError,
+        ),
+        offset: 1,
+        source_path: "<test>",
+    },
+)
+"#);
+    }
+
+    #[test]
+    fn err_if_exp() {
+        let ast = parse_suite(r"a if b else c = 42", "<test>");
+        insta::assert_debug_snapshot!(ast, @r#"
+Err(
+    ParseError {
+        error: Lexical(
+            AssignmentError,
+        ),
+        offset: 0,
+        source_path: "<test>",
+    },
+)
+"#);
+    }
+
+    #[test]
+    fn err_dict() {
+        let ast = parse_suite(r"{'a':5} = 42", "<test>");
+        insta::assert_debug_snapshot!(ast, @r#"
+Err(
+    ParseError {
+        error: Lexical(
+            AssignmentError,
+        ),
+        offset: 0,
+        source_path: "<test>",
+    },
+)
+"#);
+    }
+
+    #[test]
+    fn err_set() {
+        let ast = parse_suite(r"{a} = 42", "<test>");
+        insta::assert_debug_snapshot!(ast, @r#"
+Err(
+    ParseError {
+        error: Lexical(
+            AssignmentError,
+        ),
+        offset: 0,
+        source_path: "<test>",
+    },
+)
+"#);
+    }
+
+    #[test]
+    fn err_list_comp() {
+        let ast = parse_suite(r"[x for x in xs] = 42", "<test>");
+        insta::assert_debug_snapshot!(ast, @r#"
+Err(
+    ParseError {
+        error: Lexical(
+            AssignmentError,
+        ),
+        offset: 0,
+        source_path: "<test>",
+    },
+)
+"#);
+    }
+
+    #[test]
+    fn err_set_comp() {
+        let ast = parse_suite(r"{x for x in xs} = 42", "<test>");
+        insta::assert_debug_snapshot!(ast, @r#"
+Err(
+    ParseError {
+        error: Lexical(
+            AssignmentError,
+        ),
+        offset: 0,
+        source_path: "<test>",
+    },
+)
+"#);
+    }
+
+    #[test]
+    fn err_dict_comp() {
+        let ast = parse_suite(r"{x: x*2 for x in xs} = 42", "<test>");
+        insta::assert_debug_snapshot!(ast, @r#"
+Err(
+    ParseError {
+        error: Lexical(
+            AssignmentError,
+        ),
+        offset: 0,
+        source_path: "<test>",
+    },
+)
+"#);
+    }
+
+    #[test]
+    fn err_generator_exp() {
+        let ast = parse_suite(r"(x for x in xs) = 42", "<test>");
+        insta::assert_debug_snapshot!(ast, @r#"
+Err(
+    ParseError {
+        error: Lexical(
+            AssignmentError,
+        ),
+        offset: 0,
+        source_path: "<test>",
+    },
+)
+"#);
+    }
+
+    #[test]
+    fn err_await() {
+        let ast = parse_suite(r"await x = 42", "<test>");
+        insta::assert_debug_snapshot!(ast, @r#"
+Err(
+    ParseError {
+        error: Lexical(
+            AssignmentError,
+        ),
+        offset: 0,
+        source_path: "<test>",
+    },
+)
+"#);
+    }
+
+    #[test]
+    fn err_yield() {
+        let ast = parse_suite(r"(yield x) = 42", "<test>");
+        insta::assert_debug_snapshot!(ast, @r#"
+Err(
+    ParseError {
+        error: Lexical(
+            AssignmentError,
+        ),
+        offset: 1,
+        source_path: "<test>",
+    },
+)
+"#);
+    }
+
+    #[test]
+    fn err_yield_from() {
+        let ast = parse_suite(r"(yield from xs) = 42", "<test>");
+        insta::assert_debug_snapshot!(ast, @r#"
+Err(
+    ParseError {
+        error: Lexical(
+            AssignmentError,
+        ),
+        offset: 1,
+        source_path: "<test>",
+    },
+)
+"#);
+    }
+
+    #[test]
+    fn err_compare() {
+        let ast = parse_suite(r"a < b < c = 42", "<test>");
+        insta::assert_debug_snapshot!(ast, @r#"
+Err(
+    ParseError {
+        error: Lexical(
+            AssignmentError,
+        ),
+        offset: 0,
+        source_path: "<test>",
+    },
+)
+"#);
+    }
+
+    #[test]
+    fn err_call() {
+        let ast = parse_suite(r"foo() = 42", "<test>");
+        insta::assert_debug_snapshot!(ast, @r#"
+Err(
+    ParseError {
+        error: Lexical(
+            AssignmentError,
+        ),
+        offset: 0,
+        source_path: "<test>",
+    },
+)
+"#);
+    }
+
+    #[test]
+    fn err_formatted_value() {
+        // N.B. It looks like the parser can't generate a top-level
+        // FormattedValue, where as the official Python AST permits
+        // representing a single f-string containing just a variable as a
+        // FormattedValue directly.
+        //
+        // Bottom line is that because of this, this test is (at present)
+        // duplicative with the `fstring` test. That is, in theory these tests
+        // could fail independently, but in practice their failure or success
+        // is coupled.
+        //
+        // See: https://docs.python.org/3/library/ast.html#ast.FormattedValue
+        let ast = parse_suite(r#"f"{quux}" = 42"#, "<test>");
+        insta::assert_debug_snapshot!(ast, @r#"
+Err(
+    ParseError {
+        error: Lexical(
+            AssignmentError,
+        ),
+        offset: 0,
+        source_path: "<test>",
+    },
+)
+"#);
+    }
+
+    #[test]
+    fn err_fstring() {
+        let ast = parse_suite(r#"f"{foo} and {bar}" = 42"#, "<test>");
+        insta::assert_debug_snapshot!(ast, @r#"
+Err(
+    ParseError {
+        error: Lexical(
+            AssignmentError,
+        ),
+        offset: 0,
+        source_path: "<test>",
+    },
+)
+"#);
+    }
+
+    #[test]
+    fn err_string_literal() {
+        let ast = parse_suite(r#""foo" = 42"#, "<test>");
+        insta::assert_debug_snapshot!(ast, @r#"
+Err(
+    ParseError {
+        error: Lexical(
+            AssignmentError,
+        ),
+        offset: 0,
+        source_path: "<test>",
+    },
+)
+"#);
+    }
+
+    #[test]
+    fn err_bytes_literal() {
+        let ast = parse_suite(r#"b"foo" = 42"#, "<test>");
+        insta::assert_debug_snapshot!(ast, @r#"
+Err(
+    ParseError {
+        error: Lexical(
+            AssignmentError,
+        ),
+        offset: 0,
+        source_path: "<test>",
+    },
+)
+"#);
+    }
+
+    #[test]
+    fn err_number_literal() {
+        let ast = parse_suite(r"123 = 42", "<test>");
+        insta::assert_debug_snapshot!(ast, @r#"
+Err(
+    ParseError {
+        error: Lexical(
+            AssignmentError,
+        ),
+        offset: 0,
+        source_path: "<test>",
+    },
+)
+"#);
+    }
+
+    #[test]
+    fn err_boolean_literal() {
+        let ast = parse_suite(r"True = 42", "<test>");
+        insta::assert_debug_snapshot!(ast, @r#"
+Err(
+    ParseError {
+        error: Lexical(
+            AssignmentError,
+        ),
+        offset: 0,
+        source_path: "<test>",
+    },
+)
+"#);
+    }
+
+    #[test]
+    fn err_none_literal() {
+        let ast = parse_suite(r"None = 42", "<test>");
+        insta::assert_debug_snapshot!(ast, @r#"
+Err(
+    ParseError {
+        error: Lexical(
+            AssignmentError,
+        ),
+        offset: 0,
+        source_path: "<test>",
+    },
+)
+"#);
+    }
+
+    #[test]
+    fn err_ellipsis_literal() {
+        let ast = parse_suite(r"... = 42", "<test>");
+        insta::assert_debug_snapshot!(ast, @r#"
+Err(
+    ParseError {
+        error: Lexical(
+            AssignmentError,
+        ),
+        offset: 0,
+        source_path: "<test>",
+    },
+)
+"#);
+    }
+
+    #[test]
+    fn err_starred() {
+        let ast = parse_suite(r"*foo() = 42", "<test>");
+        insta::assert_debug_snapshot!(ast, @r#"
+Err(
+    ParseError {
+        error: Lexical(
+            AssignmentError,
+        ),
+        offset: 1,
+        source_path: "<test>",
+    },
+)
+"#);
+    }
+
+    #[test]
+    fn err_list() {
+        let ast = parse_suite(r"[x, foo(), y] = [42, 42, 42]", "<test>");
+        insta::assert_debug_snapshot!(ast, @r#"
+Err(
+    ParseError {
+        error: Lexical(
+            AssignmentError,
+        ),
+        offset: 4,
+        source_path: "<test>",
+    },
+)
+"#);
+    }
+
+    #[test]
+    fn err_list_nested() {
+        let ast = parse_suite(r"[[a, b], [[42]], d] = [[1, 2], [[3]], 4]", "<test>");
+        insta::assert_debug_snapshot!(ast, @r#"
+Err(
+    ParseError {
+        error: Lexical(
+            AssignmentError,
+        ),
+        offset: 11,
+        source_path: "<test>",
+    },
+)
+"#);
+    }
+
+    #[test]
+    fn err_tuple() {
+        let ast = parse_suite(r"(x, foo(), y) = (42, 42, 42)", "<test>");
+        insta::assert_debug_snapshot!(ast, @r#"
+Err(
+    ParseError {
+        error: Lexical(
+            AssignmentError,
+        ),
+        offset: 4,
+        source_path: "<test>",
+    },
+)
+"#);
+    }
+
+    // This last group of tests checks that assignments we expect to be parsed
+    // (including some interesting ones) continue to be parsed successfully.
+
+    #[test]
+    fn ok_starred() {
+        let ast = parse_suite(r"*foo = 42", "<test>");
+        insta::assert_debug_snapshot!(ast);
+    }
+
+    #[test]
+    fn ok_list() {
+        let ast = parse_suite(r"[x, y, z] = [1, 2, 3]", "<test>");
+        insta::assert_debug_snapshot!(ast);
+    }
+
+    #[test]
+    fn ok_tuple() {
+        let ast = parse_suite(r"(x, y, z) = (1, 2, 3)", "<test>");
+        insta::assert_debug_snapshot!(ast);
+    }
+
+    #[test]
+    fn ok_subscript_normal() {
+        let ast = parse_suite(r"x[0] = 42", "<test>");
+        insta::assert_debug_snapshot!(ast);
+    }
+
+    // This is actually a type error, not a syntax error. So check that it
+    // doesn't fail parsing.
+    #[test]
+    fn ok_subscript_weird() {
+        let ast = parse_suite(r"5[0] = 42", "<test>");
+        insta::assert_debug_snapshot!(ast);
+    }
+
+    #[test]
+    fn ok_slice_normal() {
+        let ast = parse_suite(r"x[1:2] = [42]", "<test>");
+        insta::assert_debug_snapshot!(ast);
+    }
+
+    // This is actually a type error, not a syntax error. So check that it
+    // doesn't fail parsing.
+    #[test]
+    fn ok_slice_weird() {
+        let ast = parse_suite(r"5[1:2] = [42]", "<test>");
+        insta::assert_debug_snapshot!(ast);
+    }
+
+    #[test]
+    fn ok_attribute_normal() {
+        let ast = parse_suite(r"foo.bar = 42", "<test>");
+        insta::assert_debug_snapshot!(ast);
+    }
+
+    // This is actually an attribute error, not a syntax error. So check that
+    // it doesn't fail parsing.
+    #[test]
+    fn ok_attribute_weird() {
+        let ast = parse_suite(r#""foo".y = 42"#, "<test>");
+        insta::assert_debug_snapshot!(ast);
+    }
+
+    #[test]
+    fn ok_name() {
+        let ast = parse_suite(r"foo = 42", "<test>");
+        insta::assert_debug_snapshot!(ast);
+    }
+
+    // This is a sanity test for what looks like an ipython directive being
+    // assigned to. Although this doesn't actually parse as an assignment
+    // statement, but rather, a directive whose value is `foo = 42`.
+    #[test]
+    fn ok_ipy_escape_command() {
+        use crate::Mode;
+
+        let src = r"!foo = 42";
+        let tokens = crate::lexer::lex(src, Mode::Ipython);
+        let ast = crate::parse_tokens(tokens, src, Mode::Ipython, "<test>");
+        insta::assert_debug_snapshot!(ast);
+    }
+
+    #[test]
+    fn ok_assignment_expr() {
+        let ast = parse_suite(r"(x := 5)", "<test>");
+        insta::assert_debug_snapshot!(ast);
+    }
+}

crates/ruff_python_parser/src/lexer.rs

@@ -1344,6 +1344,8 @@ pub enum LexicalErrorType {
     LineContinuationError,
     /// An unexpected end of file was encountered.
     Eof,
+    /// Occurs when a syntactically invalid assignment was encountered.
+    AssignmentError,
     /// An unexpected error occurred.
     OtherError(String),
 }
@@ -1389,6 +1391,7 @@ impl std::fmt::Display for LexicalErrorType {
                 write!(f, "unexpected character after line continuation character")
             }
             LexicalErrorType::Eof => write!(f, "unexpected EOF while parsing"),
+            LexicalErrorType::AssignmentError => write!(f, "invalid assignment target"),
             LexicalErrorType::OtherError(msg) => write!(f, "{msg}"),
         }
     }

crates/ruff_python_parser/src/lib.rs

@@ -123,6 +123,7 @@ use crate::lexer::LexResult;
 mod function;
 // Skip flattening lexer to distinguish from full ruff_python_parser
 mod context;
+mod invalid;
 pub mod lexer;
 mod parser;
 mod soft_keywords;

crates/ruff_python_parser/src/python.lalrpop

@@ -13,6 +13,7 @@ use crate::{
     context::set_context,
     string::{StringType, concatenate_strings, parse_fstring_middle, parse_string_literal},
     token::{self, StringKind},
+    invalid,
 };
 use lalrpop_util::ParseError;
 
@@ -108,12 +109,12 @@ DelStatement: ast::Stmt = {
 };
 
 ExpressionStatement: ast::Stmt = {
-    <location:@L> <expression:TestOrStarExprList> <suffix:AssignSuffix*> <end_location:@R> => {
+    <location:@L> <expression:TestOrStarExprList> <suffix:AssignSuffix*> <end_location:@R> =>? {
         // Just an expression, no assignment:
         if suffix.is_empty() {
-            ast::Stmt::Expr(
+            Ok(ast::Stmt::Expr(
                 ast::StmtExpr { value: Box::new(expression.into()), range: (location..end_location).into() }
-            )
+            ))
         } else {
             let mut targets = vec![set_context(expression.into(), ast::ExprContext::Store)];
             let mut values = suffix;
@@ -123,25 +124,27 @@ ExpressionStatement: ast::Stmt = {
             for target in values {
                 targets.push(set_context(target.into(), ast::ExprContext::Store));
             }
-
-            ast::Stmt::Assign(
+            invalid::assignment_targets(&targets)?;
+            Ok(ast::Stmt::Assign(
                 ast::StmtAssign { targets, value, range: (location..end_location).into() }
-            )
+            ))
         }
     },
-    <location:@L> <target:TestOrStarExprList> <op:AugAssign> <rhs:TestListOrYieldExpr> <end_location:@R> => {
-        ast::Stmt::AugAssign(
+    <location:@L> <target:TestOrStarExprList> <op:AugAssign> <rhs:TestListOrYieldExpr> <end_location:@R> =>? {
+        invalid::assignment_target(&target.expr)?;
+        Ok(ast::Stmt::AugAssign(
             ast::StmtAugAssign {
                 target: Box::new(set_context(target.into(), ast::ExprContext::Store)),
                 op,
                 value: Box::new(rhs.into()),
                 range: (location..end_location).into()
             },
-        )
+        ))
     },
-    <location:@L> <target:Test<"all">> ":" <annotation:Test<"all">> <rhs:AssignSuffix?> <end_location:@R> => {
+    <location:@L> <target:Test<"all">> ":" <annotation:Test<"all">> <rhs:AssignSuffix?> <end_location:@R> =>? {
         let simple = target.expr.is_name_expr();
-        ast::Stmt::AnnAssign(
+        invalid::assignment_target(&target.expr)?;
+        Ok(ast::Stmt::AnnAssign(
             ast::StmtAnnAssign {
                 target: Box::new(set_context(target.into(), ast::ExprContext::Store)),
                 annotation: Box::new(annotation.into()),
@@ -149,7 +152,7 @@ ExpressionStatement: ast::Stmt = {
                 simple,
                 range: (location..end_location).into()
             },
-        )
+        ))
     },
 };
 

crates/ruff_python_parser/src/python.rs

@@ -1,5 +1,5 @@
 // auto-generated: "lalrpop 0.20.0"
-// sha3: c798bc6e7bd9950e88dd5d950470865a75b5ff0352f4fc7fb51f13147de6ba6c
+// sha3: b8ac4a859b69d580e50733d39c96a3fe018f568e71e532ebb3153a19902e64e5
 use ruff_text_size::{Ranged, TextLen, TextRange, TextSize};
 use ruff_python_ast::{self as ast, Int, IpyEscapeKind};
 use crate::{
@@ -10,6 +10,7 @@ use crate::{
     context::set_context,
     string::{StringType, concatenate_strings, parse_fstring_middle, parse_string_literal},
     token::{self, StringKind},
+    invalid,
 };
 use lalrpop_util::ParseError;
 #[allow(unused_extern_crates)]
@@ -33,6 +34,7 @@ mod __parse__Top {
     context::set_context,
     string::{StringType, concatenate_strings, parse_fstring_middle, parse_string_literal},
     token::{self, StringKind},
+    invalid,
 };
     use lalrpop_util::ParseError;
     #[allow(unused_extern_crates)]
@@ -13725,19 +13727,76 @@ mod __parse__Top {
                 __reduce356(source_code, mode, __lookahead_start, __symbols, core::marker::PhantomData::<()>)
             }
             357 => {
-                __reduce357(source_code, mode, __lookahead_start, __symbols, core::marker::PhantomData::<()>)
+                // ExpressionStatement = GenericList<TestOrStarExpr> => ActionFn(1752);
+                let __sym0 = __pop_Variant15(__symbols);
+                let __start = __sym0.0;
+                let __end = __sym0.2;
+                let __nt = match super::__action1752::<>(source_code, mode, __sym0) {
+                    Ok(v) => v,
+                    Err(e) => return Some(Err(e)),
+                };
+                __symbols.push((__start, __Symbol::Variant37(__nt), __end));
+                (1, 137)
             }
             358 => {
-                __reduce358(source_code, mode, __lookahead_start, __symbols, core::marker::PhantomData::<()>)
+                // ExpressionStatement = GenericList<TestOrStarExpr>, AssignSuffix+ => ActionFn(1753);
+                assert!(__symbols.len() >= 2);
+                let __sym1 = __pop_Variant17(__symbols);
+                let __sym0 = __pop_Variant15(__symbols);
+                let __start = __sym0.0;
+                let __end = __sym1.2;
+                let __nt = match super::__action1753::<>(source_code, mode, __sym0, __sym1) {
+                    Ok(v) => v,
+                    Err(e) => return Some(Err(e)),
+                };
+                __symbols.push((__start, __Symbol::Variant37(__nt), __end));
+                (2, 137)
             }
             359 => {
-                __reduce359(source_code, mode, __lookahead_start, __symbols, core::marker::PhantomData::<()>)
+                // ExpressionStatement = GenericList<TestOrStarExpr>, AugAssign, TestListOrYieldExpr => ActionFn(1754);
+                assert!(__symbols.len() >= 3);
+                let __sym2 = __pop_Variant15(__symbols);
+                let __sym1 = __pop_Variant49(__symbols);
+                let __sym0 = __pop_Variant15(__symbols);
+                let __start = __sym0.0;
+                let __end = __sym2.2;
+                let __nt = match super::__action1754::<>(source_code, mode, __sym0, __sym1, __sym2) {
+                    Ok(v) => v,
+                    Err(e) => return Some(Err(e)),
+                };
+                __symbols.push((__start, __Symbol::Variant37(__nt), __end));
+                (3, 137)
             }
             360 => {
-                __reduce360(source_code, mode, __lookahead_start, __symbols, core::marker::PhantomData::<()>)
+                // ExpressionStatement = Test<"all">, ":", Test<"all">, AssignSuffix => ActionFn(1531);
+                assert!(__symbols.len() >= 4);
+                let __sym3 = __pop_Variant15(__symbols);
+                let __sym2 = __pop_Variant15(__symbols);
+                let __sym1 = __pop_Variant0(__symbols);
+                let __sym0 = __pop_Variant15(__symbols);
+                let __start = __sym0.0;
+                let __end = __sym3.2;
+                let __nt = match super::__action1531::<>(source_code, mode, __sym0, __sym1, __sym2, __sym3) {
+                    Ok(v) => v,
+                    Err(e) => return Some(Err(e)),
+                };
+                __symbols.push((__start, __Symbol::Variant37(__nt), __end));
+                (4, 137)
             }
             361 => {
-                __reduce361(source_code, mode, __lookahead_start, __symbols, core::marker::PhantomData::<()>)
+                // ExpressionStatement = Test<"all">, ":", Test<"all"> => ActionFn(1532);
+                assert!(__symbols.len() >= 3);
+                let __sym2 = __pop_Variant15(__symbols);
+                let __sym1 = __pop_Variant0(__symbols);
+                let __sym0 = __pop_Variant15(__symbols);
+                let __start = __sym0.0;
+                let __end = __sym2.2;
+                let __nt = match super::__action1532::<>(source_code, mode, __sym0, __sym1, __sym2) {
+                    Ok(v) => v,
+                    Err(e) => return Some(Err(e)),
+                };
+                __symbols.push((__start, __Symbol::Variant37(__nt), __end));
+                (3, 137)
             }
             362 => {
                 // FStringConversion = "!", name => ActionFn(800);
@@ -24718,103 +24777,6 @@ mod __parse__Top {
         __symbols.push((__start, __Symbol::Variant15(__nt), __end));
         (1, 136)
     }
-    pub(crate) fn __reduce357<
-    >(
-        source_code: &str,
-        mode: Mode,
-        __lookahead_start: Option<&TextSize>,
-        __symbols: &mut alloc::vec::Vec<(TextSize,__Symbol<>,TextSize)>,
-        _: core::marker::PhantomData<()>,
-    ) -> (usize, usize)
-    {
-        // ExpressionStatement = GenericList<TestOrStarExpr> => ActionFn(1752);
-        let __sym0 = __pop_Variant15(__symbols);
-        let __start = __sym0.0;
-        let __end = __sym0.2;
-        let __nt = super::__action1752::<>(source_code, mode, __sym0);
-        __symbols.push((__start, __Symbol::Variant37(__nt), __end));
-        (1, 137)
-    }
-    pub(crate) fn __reduce358<
-    >(
-        source_code: &str,
-        mode: Mode,
-        __lookahead_start: Option<&TextSize>,
-        __symbols: &mut alloc::vec::Vec<(TextSize,__Symbol<>,TextSize)>,
-        _: core::marker::PhantomData<()>,
-    ) -> (usize, usize)
-    {
-        // ExpressionStatement = GenericList<TestOrStarExpr>, AssignSuffix+ => ActionFn(1753);
-        assert!(__symbols.len() >= 2);
-        let __sym1 = __pop_Variant17(__symbols);
-        let __sym0 = __pop_Variant15(__symbols);
-        let __start = __sym0.0;
-        let __end = __sym1.2;
-        let __nt = super::__action1753::<>(source_code, mode, __sym0, __sym1);
-        __symbols.push((__start, __Symbol::Variant37(__nt), __end));
-        (2, 137)
-    }
-    pub(crate) fn __reduce359<
-    >(
-        source_code: &str,
-        mode: Mode,
-        __lookahead_start: Option<&TextSize>,
-        __symbols: &mut alloc::vec::Vec<(TextSize,__Symbol<>,TextSize)>,
-        _: core::marker::PhantomData<()>,
-    ) -> (usize, usize)
-    {
-        // ExpressionStatement = GenericList<TestOrStarExpr>, AugAssign, TestListOrYieldExpr => ActionFn(1754);
-        assert!(__symbols.len() >= 3);
-        let __sym2 = __pop_Variant15(__symbols);
-        let __sym1 = __pop_Variant49(__symbols);
-        let __sym0 = __pop_Variant15(__symbols);
-        let __start = __sym0.0;
-        let __end = __sym2.2;
-        let __nt = super::__action1754::<>(source_code, mode, __sym0, __sym1, __sym2);
-        __symbols.push((__start, __Symbol::Variant37(__nt), __end));
-        (3, 137)
-    }
-    pub(crate) fn __reduce360<
-    >(
-        source_code: &str,
-        mode: Mode,
-        __lookahead_start: Option<&TextSize>,
-        __symbols: &mut alloc::vec::Vec<(TextSize,__Symbol<>,TextSize)>,
-        _: core::marker::PhantomData<()>,
-    ) -> (usize, usize)
-    {
-        // ExpressionStatement = Test<"all">, ":", Test<"all">, AssignSuffix => ActionFn(1531);
-        assert!(__symbols.len() >= 4);
-        let __sym3 = __pop_Variant15(__symbols);
-        let __sym2 = __pop_Variant15(__symbols);
-        let __sym1 = __pop_Variant0(__symbols);
-        let __sym0 = __pop_Variant15(__symbols);
-        let __start = __sym0.0;
-        let __end = __sym3.2;
-        let __nt = super::__action1531::<>(source_code, mode, __sym0, __sym1, __sym2, __sym3);
-        __symbols.push((__start, __Symbol::Variant37(__nt), __end));
-        (4, 137)
-    }
-    pub(crate) fn __reduce361<
-    >(
-        source_code: &str,
-        mode: Mode,
-        __lookahead_start: Option<&TextSize>,
-        __symbols: &mut alloc::vec::Vec<(TextSize,__Symbol<>,TextSize)>,
-        _: core::marker::PhantomData<()>,
-    ) -> (usize, usize)
-    {
-        // ExpressionStatement = Test<"all">, ":", Test<"all"> => ActionFn(1532);
-        assert!(__symbols.len() >= 3);
-        let __sym2 = __pop_Variant15(__symbols);
-        let __sym1 = __pop_Variant0(__symbols);
-        let __sym0 = __pop_Variant15(__symbols);
-        let __start = __sym0.0;
-        let __end = __sym2.2;
-        let __nt = super::__action1532::<>(source_code, mode, __sym0, __sym1, __sym2);
-        __symbols.push((__start, __Symbol::Variant37(__nt), __end));
-        (3, 137)
-    }
     pub(crate) fn __reduce363<
     >(
         source_code: &str,
@@ -32789,14 +32751,14 @@ fn __action26<
     (_, expression, _): (TextSize, ast::ParenthesizedExpr, TextSize),
     (_, suffix, _): (TextSize, alloc::vec::Vec<ast::ParenthesizedExpr>, TextSize),
     (_, end_location, _): (TextSize, TextSize, TextSize),
-) -> ast::Stmt
+) -> Result<ast::Stmt,__lalrpop_util::ParseError<TextSize,token::Tok,LexicalError>>
 {
     {
         // Just an expression, no assignment:
         if suffix.is_empty() {
-            ast::Stmt::Expr(
+            Ok(ast::Stmt::Expr(
                 ast::StmtExpr { value: Box::new(expression.into()), range: (location..end_location).into() }
-            )
+            ))
         } else {
             let mut targets = vec![set_context(expression.into(), ast::ExprContext::Store)];
             let mut values = suffix;
@@ -32806,10 +32768,10 @@ fn __action26<
             for target in values {
                 targets.push(set_context(target.into(), ast::ExprContext::Store));
             }
-
-            ast::Stmt::Assign(
+            invalid::assignment_targets(&targets)?;
+            Ok(ast::Stmt::Assign(
                 ast::StmtAssign { targets, value, range: (location..end_location).into() }
-            )
+            ))
         }
     }
 }
@@ -32825,17 +32787,18 @@ fn __action27<
     (_, op, _): (TextSize, ast::Operator, TextSize),
     (_, rhs, _): (TextSize, ast::ParenthesizedExpr, TextSize),
     (_, end_location, _): (TextSize, TextSize, TextSize),
-) -> ast::Stmt
+) -> Result<ast::Stmt,__lalrpop_util::ParseError<TextSize,token::Tok,LexicalError>>
 {
     {
-        ast::Stmt::AugAssign(
+        invalid::assignment_target(&target.expr)?;
+        Ok(ast::Stmt::AugAssign(
             ast::StmtAugAssign {
                 target: Box::new(set_context(target.into(), ast::ExprContext::Store)),
                 op,
                 value: Box::new(rhs.into()),
                 range: (location..end_location).into()
             },
-        )
+        ))
     }
 }
 
@@ -32851,11 +32814,12 @@ fn __action28<
     (_, annotation, _): (TextSize, ast::ParenthesizedExpr, TextSize),
     (_, rhs, _): (TextSize, core::option::Option<ast::ParenthesizedExpr>, TextSize),
     (_, end_location, _): (TextSize, TextSize, TextSize),
-) -> ast::Stmt
+) -> Result<ast::Stmt,__lalrpop_util::ParseError<TextSize,token::Tok,LexicalError>>
 {
     {
         let simple = target.expr.is_name_expr();
-        ast::Stmt::AnnAssign(
+        invalid::assignment_target(&target.expr)?;
+        Ok(ast::Stmt::AnnAssign(
             ast::StmtAnnAssign {
                 target: Box::new(set_context(target.into(), ast::ExprContext::Store)),
                 annotation: Box::new(annotation.into()),
@@ -32863,7 +32827,7 @@ fn __action28<
                 simple,
                 range: (location..end_location).into()
             },
-        )
+        ))
     }
 }
 
@@ -48215,7 +48179,7 @@ fn __action797<
     __0: (TextSize, ast::ParenthesizedExpr, TextSize),
     __1: (TextSize, alloc::vec::Vec<ast::ParenthesizedExpr>, TextSize),
     __2: (TextSize, TextSize, TextSize),
-) -> ast::Stmt
+) -> Result<ast::Stmt,__lalrpop_util::ParseError<TextSize,token::Tok,LexicalError>>
 {
     let __start0 = __0.0;
     let __end0 = __0.0;
@@ -48246,7 +48210,7 @@ fn __action798<
     __1: (TextSize, ast::Operator, TextSize),
     __2: (TextSize, ast::ParenthesizedExpr, TextSize),
     __3: (TextSize, TextSize, TextSize),
-) -> ast::Stmt
+) -> Result<ast::Stmt,__lalrpop_util::ParseError<TextSize,token::Tok,LexicalError>>
 {
     let __start0 = __0.0;
     let __end0 = __0.0;
@@ -48279,7 +48243,7 @@ fn __action799<
     __2: (TextSize, ast::ParenthesizedExpr, TextSize),
     __3: (TextSize, core::option::Option<ast::ParenthesizedExpr>, TextSize),
     __4: (TextSize, TextSize, TextSize),
-) -> ast::Stmt
+) -> Result<ast::Stmt,__lalrpop_util::ParseError<TextSize,token::Tok,LexicalError>>
 {
     let __start0 = __0.0;
     let __end0 = __0.0;
@@ -64278,7 +64242,7 @@ fn __action1309<
     mode: Mode,
     __0: (TextSize, ast::ParenthesizedExpr, TextSize),
     __1: (TextSize, alloc::vec::Vec<ast::ParenthesizedExpr>, TextSize),
-) -> ast::Stmt
+) -> Result<ast::Stmt,__lalrpop_util::ParseError<TextSize,token::Tok,LexicalError>>
 {
     let __start0 = __1.2;
     let __end0 = __1.2;
@@ -64307,7 +64271,7 @@ fn __action1310<
     __0: (TextSize, ast::ParenthesizedExpr, TextSize),
     __1: (TextSize, ast::Operator, TextSize),
     __2: (TextSize, ast::ParenthesizedExpr, TextSize),
-) -> ast::Stmt
+) -> Result<ast::Stmt,__lalrpop_util::ParseError<TextSize,token::Tok,LexicalError>>
 {
     let __start0 = __2.2;
     let __end0 = __2.2;
@@ -64338,7 +64302,7 @@ fn __action1311<
     __1: (TextSize, token::Tok, TextSize),
     __2: (TextSize, ast::ParenthesizedExpr, TextSize),
     __3: (TextSize, core::option::Option<ast::ParenthesizedExpr>, TextSize),
-) -> ast::Stmt
+) -> Result<ast::Stmt,__lalrpop_util::ParseError<TextSize,token::Tok,LexicalError>>
 {
     let __start0 = __3.2;
     let __end0 = __3.2;
@@ -71035,7 +70999,7 @@ fn __action1529<
     source_code: &str,
     mode: Mode,
     __0: (TextSize, ast::ParenthesizedExpr, TextSize),
-) -> ast::Stmt
+) -> Result<ast::Stmt,__lalrpop_util::ParseError<TextSize,token::Tok,LexicalError>>
 {
     let __start0 = __0.2;
     let __end0 = __0.2;
@@ -71062,7 +71026,7 @@ fn __action1530<
     mode: Mode,
     __0: (TextSize, ast::ParenthesizedExpr, TextSize),
     __1: (TextSize, alloc::vec::Vec<ast::ParenthesizedExpr>, TextSize),
-) -> ast::Stmt
+) -> Result<ast::Stmt,__lalrpop_util::ParseError<TextSize,token::Tok,LexicalError>>
 {
     let __start0 = __1.0;
     let __end0 = __1.2;
@@ -71090,7 +71054,7 @@ fn __action1531<
     __1: (TextSize, token::Tok, TextSize),
     __2: (TextSize, ast::ParenthesizedExpr, TextSize),
     __3: (TextSize, ast::ParenthesizedExpr, TextSize),
-) -> ast::Stmt
+) -> Result<ast::Stmt,__lalrpop_util::ParseError<TextSize,token::Tok,LexicalError>>
 {
     let __start0 = __3.0;
     let __end0 = __3.2;
@@ -71119,7 +71083,7 @@ fn __action1532<
     __0: (TextSize, ast::ParenthesizedExpr, TextSize),
     __1: (TextSize, token::Tok, TextSize),
     __2: (TextSize, ast::ParenthesizedExpr, TextSize),
-) -> ast::Stmt
+) -> Result<ast::Stmt,__lalrpop_util::ParseError<TextSize,token::Tok,LexicalError>>
 {
     let __start0 = __2.2;
     let __end0 = __2.2;
@@ -78391,7 +78355,7 @@ fn __action1752<
     source_code: &str,
     mode: Mode,
     __0: (TextSize, ast::ParenthesizedExpr, TextSize),
-) -> ast::Stmt
+) -> Result<ast::Stmt,__lalrpop_util::ParseError<TextSize,token::Tok,LexicalError>>
 {
     let __start0 = __0.0;
     let __end0 = __0.2;
@@ -78416,7 +78380,7 @@ fn __action1753<
     mode: Mode,
     __0: (TextSize, ast::ParenthesizedExpr, TextSize),
     __1: (TextSize, alloc::vec::Vec<ast::ParenthesizedExpr>, TextSize),
-) -> ast::Stmt
+) -> Result<ast::Stmt,__lalrpop_util::ParseError<TextSize,token::Tok,LexicalError>>
 {
     let __start0 = __0.0;
     let __end0 = __0.2;
@@ -78443,7 +78407,7 @@ fn __action1754<
     __0: (TextSize, ast::ParenthesizedExpr, TextSize),
     __1: (TextSize, ast::Operator, TextSize),
     __2: (TextSize, ast::ParenthesizedExpr, TextSize),
-) -> ast::Stmt
+) -> Result<ast::Stmt,__lalrpop_util::ParseError<TextSize,token::Tok,LexicalError>>
 {
     let __start0 = __0.0;
     let __end0 = __0.2;

crates/ruff_python_parser/src/snapshots/ruff_python_parser__invalid__tests__ok_assignment_expr.snap

@@ -0,0 +1,33 @@
+---
+source: crates/ruff_python_parser/src/invalid.rs
+expression: ast
+---
+Ok(
+    [
+        Expr(
+            StmtExpr {
+                range: 0..8,
+                value: NamedExpr(
+                    ExprNamedExpr {
+                        range: 1..7,
+                        target: Name(
+                            ExprName {
+                                range: 1..2,
+                                id: "x",
+                                ctx: Store,
+                            },
+                        ),
+                        value: NumberLiteral(
+                            ExprNumberLiteral {
+                                range: 6..7,
+                                value: Int(
+                                    5,
+                                ),
+                            },
+                        ),
+                    },
+                ),
+            },
+        ),
+    ],
+)

crates/ruff_python_parser/src/snapshots/ruff_python_parser__invalid__tests__ok_attribute_normal.snap

@@ -0,0 +1,40 @@
+---
+source: crates/ruff_python_parser/src/invalid.rs
+expression: ast
+---
+Ok(
+    [
+        Assign(
+            StmtAssign {
+                range: 0..12,
+                targets: [
+                    Attribute(
+                        ExprAttribute {
+                            range: 0..7,
+                            value: Name(
+                                ExprName {
+                                    range: 0..3,
+                                    id: "foo",
+                                    ctx: Load,
+                                },
+                            ),
+                            attr: Identifier {
+                                id: "bar",
+                                range: 4..7,
+                            },
+                            ctx: Store,
+                        },
+                    ),
+                ],
+                value: NumberLiteral(
+                    ExprNumberLiteral {
+                        range: 10..12,
+                        value: Int(
+                            42,
+                        ),
+                    },
+                ),
+            },
+        ),
+    ],
+)

crates/ruff_python_parser/src/snapshots/ruff_python_parser__invalid__tests__ok_attribute_weird.snap

@@ -0,0 +1,41 @@
+---
+source: crates/ruff_python_parser/src/invalid.rs
+expression: ast
+---
+Ok(
+    [
+        Assign(
+            StmtAssign {
+                range: 0..12,
+                targets: [
+                    Attribute(
+                        ExprAttribute {
+                            range: 0..7,
+                            value: StringLiteral(
+                                ExprStringLiteral {
+                                    range: 0..5,
+                                    value: "foo",
+                                    unicode: false,
+                                    implicit_concatenated: false,
+                                },
+                            ),
+                            attr: Identifier {
+                                id: "y",
+                                range: 6..7,
+                            },
+                            ctx: Store,
+                        },
+                    ),
+                ],
+                value: NumberLiteral(
+                    ExprNumberLiteral {
+                        range: 10..12,
+                        value: Int(
+                            42,
+                        ),
+                    },
+                ),
+            },
+        ),
+    ],
+)

crates/ruff_python_parser/src/snapshots/ruff_python_parser__invalid__tests__ok_ipy_escape_command.snap

@@ -0,0 +1,20 @@
+---
+source: crates/ruff_python_parser/src/invalid.rs
+expression: ast
+---
+Ok(
+    Module(
+        ModModule {
+            range: 0..9,
+            body: [
+                IpyEscapeCommand(
+                    StmtIpyEscapeCommand {
+                        range: 0..9,
+                        kind: Shell,
+                        value: "foo = 42",
+                    },
+                ),
+            ],
+        },
+    ),
+)

crates/ruff_python_parser/src/snapshots/ruff_python_parser__invalid__tests__ok_list.snap

@@ -0,0 +1,76 @@
+---
+source: crates/ruff_python_parser/src/invalid.rs
+expression: ast
+---
+Ok(
+    [
+        Assign(
+            StmtAssign {
+                range: 0..21,
+                targets: [
+                    List(
+                        ExprList {
+                            range: 0..9,
+                            elts: [
+                                Name(
+                                    ExprName {
+                                        range: 1..2,
+                                        id: "x",
+                                        ctx: Store,
+                                    },
+                                ),
+                                Name(
+                                    ExprName {
+                                        range: 4..5,
+                                        id: "y",
+                                        ctx: Store,
+                                    },
+                                ),
+                                Name(
+                                    ExprName {
+                                        range: 7..8,
+                                        id: "z",
+                                        ctx: Store,
+                                    },
+                                ),
+                            ],
+                            ctx: Store,
+                        },
+                    ),
+                ],
+                value: List(
+                    ExprList {
+                        range: 12..21,
+                        elts: [
+                            NumberLiteral(
+                                ExprNumberLiteral {
+                                    range: 13..14,
+                                    value: Int(
+                                        1,
+                                    ),
+                                },
+                            ),
+                            NumberLiteral(
+                                ExprNumberLiteral {
+                                    range: 16..17,
+                                    value: Int(
+                                        2,
+                                    ),
+                                },
+                            ),
+                            NumberLiteral(
+                                ExprNumberLiteral {
+                                    range: 19..20,
+                                    value: Int(
+                                        3,
+                                    ),
+                                },
+                            ),
+                        ],
+                        ctx: Load,
+                    },
+                ),
+            },
+        ),
+    ],
+)

crates/ruff_python_parser/src/snapshots/ruff_python_parser__invalid__tests__ok_name.snap

@@ -0,0 +1,30 @@
+---
+source: crates/ruff_python_parser/src/invalid.rs
+expression: ast
+---
+Ok(
+    [
+        Assign(
+            StmtAssign {
+                range: 0..8,
+                targets: [
+                    Name(
+                        ExprName {
+                            range: 0..3,
+                            id: "foo",
+                            ctx: Store,
+                        },
+                    ),
+                ],
+                value: NumberLiteral(
+                    ExprNumberLiteral {
+                        range: 6..8,
+                        value: Int(
+                            42,
+                        ),
+                    },
+                ),
+            },
+        ),
+    ],
+)

crates/ruff_python_parser/src/snapshots/ruff_python_parser__invalid__tests__ok_slice_normal.snap

@@ -0,0 +1,70 @@
+---
+source: crates/ruff_python_parser/src/invalid.rs
+expression: ast
+---
+Ok(
+    [
+        Assign(
+            StmtAssign {
+                range: 0..13,
+                targets: [
+                    Subscript(
+                        ExprSubscript {
+                            range: 0..6,
+                            value: Name(
+                                ExprName {
+                                    range: 0..1,
+                                    id: "x",
+                                    ctx: Load,
+                                },
+                            ),
+                            slice: Slice(
+                                ExprSlice {
+                                    range: 2..5,
+                                    lower: Some(
+                                        NumberLiteral(
+                                            ExprNumberLiteral {
+                                                range: 2..3,
+                                                value: Int(
+                                                    1,
+                                                ),
+                                            },
+                                        ),
+                                    ),
+                                    upper: Some(
+                                        NumberLiteral(
+                                            ExprNumberLiteral {
+                                                range: 4..5,
+                                                value: Int(
+                                                    2,
+                                                ),
+                                            },
+                                        ),
+                                    ),
+                                    step: None,
+                                },
+                            ),
+                            ctx: Store,
+                        },
+                    ),
+                ],
+                value: List(
+                    ExprList {
+                        range: 9..13,
+                        elts: [
+                            NumberLiteral(
+                                ExprNumberLiteral {
+                                    range: 10..12,
+                                    value: Int(
+                                        42,
+                                    ),
+                                },
+                            ),
+                        ],
+                        ctx: Load,
+                    },
+                ),
+            },
+        ),
+    ],
+)

crates/ruff_python_parser/src/snapshots/ruff_python_parser__invalid__tests__ok_slice_weird.snap

@@ -0,0 +1,71 @@
+---
+source: crates/ruff_python_parser/src/invalid.rs
+expression: ast
+---
+Ok(
+    [
+        Assign(
+            StmtAssign {
+                range: 0..13,
+                targets: [
+                    Subscript(
+                        ExprSubscript {
+                            range: 0..6,
+                            value: NumberLiteral(
+                                ExprNumberLiteral {
+                                    range: 0..1,
+                                    value: Int(
+                                        5,
+                                    ),
+                                },
+                            ),
+                            slice: Slice(
+                                ExprSlice {
+                                    range: 2..5,
+                                    lower: Some(
+                                        NumberLiteral(
+                                            ExprNumberLiteral {
+                                                range: 2..3,
+                                                value: Int(
+                                                    1,
+                                                ),
+                                            },
+                                        ),
+                                    ),
+                                    upper: Some(
+                                        NumberLiteral(
+                                            ExprNumberLiteral {
+                                                range: 4..5,
+                                                value: Int(
+                                                    2,
+                                                ),
+                                            },
+                                        ),
+                                    ),
+                                    step: None,
+                                },
+                            ),
+                            ctx: Store,
+                        },
+                    ),
+                ],
+                value: List(
+                    ExprList {
+                        range: 9..13,
+                        elts: [
+                            NumberLiteral(
+                                ExprNumberLiteral {
+                                    range: 10..12,
+                                    value: Int(
+                                        42,
+                                    ),
+                                },
+                            ),
+                        ],
+                        ctx: Load,
+                    },
+                ),
+            },
+        ),
+    ],
+)

crates/ruff_python_parser/src/snapshots/ruff_python_parser__invalid__tests__ok_starred.snap

@@ -0,0 +1,36 @@
+---
+source: crates/ruff_python_parser/src/invalid.rs
+expression: ast
+---
+Ok(
+    [
+        Assign(
+            StmtAssign {
+                range: 0..9,
+                targets: [
+                    Starred(
+                        ExprStarred {
+                            range: 0..4,
+                            value: Name(
+                                ExprName {
+                                    range: 1..4,
+                                    id: "foo",
+                                    ctx: Store,
+                                },
+                            ),
+                            ctx: Store,
+                        },
+                    ),
+                ],
+                value: NumberLiteral(
+                    ExprNumberLiteral {
+                        range: 7..9,
+                        value: Int(
+                            42,
+                        ),
+                    },
+                ),
+            },
+        ),
+    ],
+)

crates/ruff_python_parser/src/snapshots/ruff_python_parser__invalid__tests__ok_subscript_normal.snap

@@ -0,0 +1,44 @@
+---
+source: crates/ruff_python_parser/src/invalid.rs
+expression: ast
+---
+Ok(
+    [
+        Assign(
+            StmtAssign {
+                range: 0..9,
+                targets: [
+                    Subscript(
+                        ExprSubscript {
+                            range: 0..4,
+                            value: Name(
+                                ExprName {
+                                    range: 0..1,
+                                    id: "x",
+                                    ctx: Load,
+                                },
+                            ),
+                            slice: NumberLiteral(
+                                ExprNumberLiteral {
+                                    range: 2..3,
+                                    value: Int(
+                                        0,
+                                    ),
+                                },
+                            ),
+                            ctx: Store,
+                        },
+                    ),
+                ],
+                value: NumberLiteral(
+                    ExprNumberLiteral {
+                        range: 7..9,
+                        value: Int(
+                            42,
+                        ),
+                    },
+                ),
+            },
+        ),
+    ],
+)

crates/ruff_python_parser/src/snapshots/ruff_python_parser__invalid__tests__ok_subscript_weird.snap

@@ -0,0 +1,45 @@
+---
+source: crates/ruff_python_parser/src/invalid.rs
+expression: ast
+---
+Ok(
+    [
+        Assign(
+            StmtAssign {
+                range: 0..9,
+                targets: [
+                    Subscript(
+                        ExprSubscript {
+                            range: 0..4,
+                            value: NumberLiteral(
+                                ExprNumberLiteral {
+                                    range: 0..1,
+                                    value: Int(
+                                        5,
+                                    ),
+                                },
+                            ),
+                            slice: NumberLiteral(
+                                ExprNumberLiteral {
+                                    range: 2..3,
+                                    value: Int(
+                                        0,
+                                    ),
+                                },
+                            ),
+                            ctx: Store,
+                        },
+                    ),
+                ],
+                value: NumberLiteral(
+                    ExprNumberLiteral {
+                        range: 7..9,
+                        value: Int(
+                            42,
+                        ),
+                    },
+                ),
+            },
+        ),
+    ],
+)

crates/ruff_python_parser/src/snapshots/ruff_python_parser__invalid__tests__ok_tuple.snap

@@ -0,0 +1,76 @@
+---
+source: crates/ruff_python_parser/src/invalid.rs
+expression: ast
+---
+Ok(
+    [
+        Assign(
+            StmtAssign {
+                range: 0..21,
+                targets: [
+                    Tuple(
+                        ExprTuple {
+                            range: 0..9,
+                            elts: [
+                                Name(
+                                    ExprName {
+                                        range: 1..2,
+                                        id: "x",
+                                        ctx: Store,
+                                    },
+                                ),
+                                Name(
+                                    ExprName {
+                                        range: 4..5,
+                                        id: "y",
+                                        ctx: Store,
+                                    },
+                                ),
+                                Name(
+                                    ExprName {
+                                        range: 7..8,
+                                        id: "z",
+                                        ctx: Store,
+                                    },
+                                ),
+                            ],
+                            ctx: Store,
+                        },
+                    ),
+                ],
+                value: Tuple(
+                    ExprTuple {
+                        range: 12..21,
+                        elts: [
+                            NumberLiteral(
+                                ExprNumberLiteral {
+                                    range: 13..14,
+                                    value: Int(
+                                        1,
+                                    ),
+                                },
+                            ),
+                            NumberLiteral(
+                                ExprNumberLiteral {
+                                    range: 16..17,
+                                    value: Int(
+                                        2,
+                                    ),
+                                },
+                            ),
+                            NumberLiteral(
+                                ExprNumberLiteral {
+                                    range: 19..20,
+                                    value: Int(
+                                        3,
+                                    ),
+                                },
+                            ),
+                        ],
+                        ctx: Load,
+                    },
+                ),
+            },
+        ),
+    ],
+)

crates/ruff_python_semantic/src/model.rs

@@ -616,6 +616,16 @@ impl<'a> SemanticModel<'a> {
         self.resolved_names.get(&name.into()).copied()
     }
 
+    /// Resolves the [`ast::ExprName`] to the [`BindingId`] of the symbol it refers to, if it's the
+    /// only binding to that name in its scope.
+    pub fn only_binding(&self, name: &ast::ExprName) -> Option<BindingId> {
+        self.resolve_name(name).filter(|id| {
+            let binding = self.binding(*id);
+            let scope = &self.scopes[binding.scope];
+            scope.shadowed_binding(*id).is_none()
+        })
+    }
+
     /// Resolves the [`Expr`] to a fully-qualified symbol-name, if `value` resolves to an imported
     /// or builtin symbol.
     ///

crates/ruff_wasm/Cargo.toml

@@ -36,7 +36,7 @@ console_log = { version = "1.0.0" }
 log = { workspace = true }
 
 serde = { workspace = true }
-serde-wasm-bindgen = { version = "0.6.0" }
+serde-wasm-bindgen = { version = "0.6.1" }
 wasm-bindgen = { version = "0.2.84" }
 js-sys = { version = "0.3.61" }
 

crates/ruff_workspace/src/options.rs

@@ -298,10 +298,18 @@ pub struct Options {
     /// For example, to represent supporting Python >=3.10 or ==3.10
     /// specify `target-version = "py310"`.
     ///
-    /// If omitted, and Ruff is configured via a `pyproject.toml` file, the
-    /// target version will be inferred from its `project.requires-python`
-    /// field (e.g., `requires-python = ">=3.8"`). If Ruff is configured via
-    /// `ruff.toml` or `.ruff.toml`, no such inference will be performed.
+    /// If you're already using a `pyproject.toml` file, we recommend
+    /// `project.requires-python` instead, as it's based on Python packaging
+    /// standards, and will be respected by other tools. For example, Ruff
+    /// treats the following as identical to `target-version = "py38"`:
+    ///
+    /// ```toml
+    /// [project]
+    /// requires-python = ">=3.8"
+    /// ```
+    ///
+    /// If both are specified, `target-version` takes precedence over
+    /// `requires-python`.
     #[option(
         default = r#""py38""#,
         value_type = r#""py37" | "py38" | "py39" | "py310" | "py311" | "py312""#,

docs/configuration.md

@@ -7,147 +7,220 @@ semantics are the same.
 
 For a complete enumeration of the available configuration options, see [_Settings_](settings.md).
 
-## Using `pyproject.toml`
-
 If left unspecified, Ruff's default configuration is equivalent to:
 
-```toml
-[tool.ruff]
-# Exclude a variety of commonly ignored directories.
-exclude = [
-    ".bzr",
-    ".direnv",
-    ".eggs",
-    ".git",
-    ".git-rewrite",
-    ".hg",
-    ".mypy_cache",
-    ".nox",
-    ".pants.d",
-    ".pytype",
-    ".ruff_cache",
-    ".svn",
-    ".tox",
-    ".venv",
-    "__pypackages__",
-    "_build",
-    "buck-out",
-    "build",
-    "dist",
-    "node_modules",
-    "venv",
-]
+=== "pyproject.toml"
 
-# Same as Black.
-line-length = 88
-indent-width = 4
+    ```toml
+    [tool.ruff]
+    # Exclude a variety of commonly ignored directories.
+    exclude = [
+        ".bzr",
+        ".direnv",
+        ".eggs",
+        ".git",
+        ".git-rewrite",
+        ".hg",
+        ".mypy_cache",
+        ".nox",
+        ".pants.d",
+        ".pytype",
+        ".ruff_cache",
+        ".svn",
+        ".tox",
+        ".venv",
+        "__pypackages__",
+        "_build",
+        "buck-out",
+        "build",
+        "dist",
+        "node_modules",
+        "venv",
+    ]
 
-# Assume Python 3.8
-target-version = "py38"
+    # Same as Black.
+    line-length = 88
+    indent-width = 4
 
-[tool.ruff.lint]
-# Enable Pyflakes (`F`) and a subset of the pycodestyle (`E`)  codes by default.
-# Unlike Flake8, Ruff doesn't enable pycodestyle warnings (`W`) or
-# McCabe complexity (`C901`) by default.
-select = ["E4", "E7", "E9", "F"]
-ignore = []
+    # Assume Python 3.8
+    target-version = "py38"
 
-# Allow fix for all enabled rules (when `--fix`) is provided.
-fixable = ["ALL"]
-unfixable = []
+    [tool.ruff.lint]
+    # Enable Pyflakes (`F`) and a subset of the pycodestyle (`E`)  codes by default.
+    # Unlike Flake8, Ruff doesn't enable pycodestyle warnings (`W`) or
+    # McCabe complexity (`C901`) by default.
+    select = ["E4", "E7", "E9", "F"]
+    ignore = []
 
-# Allow unused variables when underscore-prefixed.
-dummy-variable-rgx = "^(_+|(_+[a-zA-Z0-9_]*[a-zA-Z0-9]+?))$"
+    # Allow fix for all enabled rules (when `--fix`) is provided.
+    fixable = ["ALL"]
+    unfixable = []
 
-[tool.ruff.format]
-# Like Black, use double quotes for strings.
-quote-style = "double"
+    # Allow unused variables when underscore-prefixed.
+    dummy-variable-rgx = "^(_+|(_+[a-zA-Z0-9_]*[a-zA-Z0-9]+?))$"
 
-# Like Black, indent with spaces, rather than tabs.
-indent-style = "space"
+    [tool.ruff.format]
+    # Like Black, use double quotes for strings.
+    quote-style = "double"
 
-# Like Black, respect magic trailing commas.
-skip-magic-trailing-comma = false
+    # Like Black, indent with spaces, rather than tabs.
+    indent-style = "space"
 
-# Like Black, automatically detect the appropriate line ending.
-line-ending = "auto"
-```
+    # Like Black, respect magic trailing commas.
+    skip-magic-trailing-comma = false
+
+    # Like Black, automatically detect the appropriate line ending.
+    line-ending = "auto"
+    ```
+
+=== "ruff.toml"
+
+    ```toml
+    # Exclude a variety of commonly ignored directories.
+    exclude = [
+        ".bzr",
+        ".direnv",
+        ".eggs",
+        ".git",
+        ".git-rewrite",
+        ".hg",
+        ".mypy_cache",
+        ".nox",
+        ".pants.d",
+        ".pytype",
+        ".ruff_cache",
+        ".svn",
+        ".tox",
+        ".venv",
+        "__pypackages__",
+        "_build",
+        "buck-out",
+        "build",
+        "dist",
+        "node_modules",
+        "venv",
+    ]
+
+    # Same as Black.
+    line-length = 88
+    indent-width = 4
+
+    # Assume Python 3.8
+    target-version = "py38"
+
+    [lint]
+    # Enable Pyflakes (`F`) and a subset of the pycodestyle (`E`)  codes by default.
+    # Unlike Flake8, Ruff doesn't enable pycodestyle warnings (`W`) or
+    # McCabe complexity (`C901`) by default.
+    select = ["E4", "E7", "E9", "F"]
+    ignore = []
+
+    # Allow fix for all enabled rules (when `--fix`) is provided.
+    fixable = ["ALL"]
+    unfixable = []
+
+    # Allow unused variables when underscore-prefixed.
+    dummy-variable-rgx = "^(_+|(_+[a-zA-Z0-9_]*[a-zA-Z0-9]+?))$"
+
+    [format]
+    # Like Black, use double quotes for strings.
+    quote-style = "double"
+
+    # Like Black, indent with spaces, rather than tabs.
+    indent-style = "space"
+
+    # Like Black, respect magic trailing commas.
+    skip-magic-trailing-comma = false
+
+    # Like Black, automatically detect the appropriate line ending.
+    line-ending = "auto"
+    ```
 
 As an example, the following would configure Ruff to:
 
-```toml
-[tool.ruff.lint]
-# 1. Enable flake8-bugbear (`B`) rules, in addition to the defaults.
-select = ["E4", "E7", "E9", "F", "B"]
+=== "pyproject.toml"
 
-# 2. Avoid enforcing line-length violations (`E501`)
-ignore = ["E501"]
+    ```toml
+    [tool.ruff.lint]
+    # 1. Enable flake8-bugbear (`B`) rules, in addition to the defaults.
+    select = ["E4", "E7", "E9", "F", "B"]
 
-# 3. Avoid trying to fix flake8-bugbear (`B`) violations.
-unfixable = ["B"]
+    # 2. Avoid enforcing line-length violations (`E501`)
+    ignore = ["E501"]
 
-# 4. Ignore `E402` (import violations) in all `__init__.py` files, and in select subdirectories.
-[tool.ruff.lint.per-file-ignores]
-"__init__.py" = ["E402"]
-"**/{tests,docs,tools}/*" = ["E402"]
+    # 3. Avoid trying to fix flake8-bugbear (`B`) violations.
+    unfixable = ["B"]
 
-[tool.ruff.format]
-# 5. Use single quotes for non-triple-quoted strings.
-quote-style = "single"
-```
+    # 4. Ignore `E402` (import violations) in all `__init__.py` files, and in select subdirectories.
+    [tool.ruff.lint.per-file-ignores]
+    "__init__.py" = ["E402"]
+    "**/{tests,docs,tools}/*" = ["E402"]
+
+    [tool.ruff.format]
+    # 5. Use single quotes for non-triple-quoted strings.
+    quote-style = "single"
+    ```
+
+=== "ruff.toml"
+
+    ```toml
+    [lint]
+    # 1. Enable flake8-bugbear (`B`) rules, in addition to the defaults.
+    select = ["E4", "E7", "E9", "F", "B"]
+
+    # 2. Avoid enforcing line-length violations (`E501`)
+    ignore = ["E501"]
+
+    # 3. Avoid trying to fix flake8-bugbear (`B`) violations.
+    unfixable = ["B"]
+
+    # 4. Ignore `E402` (import violations) in all `__init__.py` files, and in select subdirectories.
+    [lint.per-file-ignores]
+    "__init__.py" = ["E402"]
+    "**/{tests,docs,tools}/*" = ["E402"]
+
+    [format]
+    # 5. Use single quotes for non-triple-quoted strings.
+    quote-style = "single"
+    ```
 
 Linter plugin configurations are expressed as subsections, e.g.:
 
-```toml
-[tool.ruff.lint]
-# Add "Q" to the list of enabled codes.
-select = ["E4", "E7", "E9", "F", "Q"]
+=== "pyproject.toml"
 
-[tool.ruff.lint.flake8-quotes]
-docstring-quotes = "double"
-```
+    ```toml
+    [tool.ruff.lint]
+    # Add "Q" to the list of enabled codes.
+    select = ["E4", "E7", "E9", "F", "Q"]
 
-For a complete enumeration of the available configuration options, see [_Settings_](settings.md).
+    [tool.ruff.lint.flake8-quotes]
+    docstring-quotes = "double"
+    ```
 
-## Using `ruff.toml`
+=== "ruff.toml"
 
-As an alternative to `pyproject.toml`, Ruff will also respect a `ruff.toml` (or `.ruff.toml`) file,
-which implements an equivalent schema (though in the `ruff.toml` and `.ruff.toml` versions, the
+    ```toml
+    [lint]
+    # Add "Q" to the list of enabled codes.
+    select = ["E4", "E7", "E9", "F", "Q"]
+
+    [lint.flake8-quotes]
+    docstring-quotes = "double"
+    ```
+
+Ruff respects `pyproject.toml`, `ruff.toml`, and `.ruff.toml` files. All three implement
+an equivalent schema (though in the `ruff.toml` and `.ruff.toml` versions, the
 `[tool.ruff]` header is omitted).
 
-For example, the `pyproject.toml` described above would be represented via the following
-`ruff.toml` (or `.ruff.toml`):
-
-```toml
-[lint]
-# Enable flake8-bugbear (`B`) rules.
-select = ["E4", "E7", "E9", "F", "B"]
-
-# Never enforce `E501` (line length violations).
-ignore = ["E501"]
-
-# Avoid trying to fix flake8-bugbear (`B`) violations.
-unfixable = ["B"]
-
-# Ignore `E402` (import violations) in all `__init__.py` files, and in select subdirectories.
-[lint.per-file-ignores]
-"__init__.py" = ["E402"]
-"**/{tests,docs,tools}/*" = ["E402"]
-
-[format]
-# Use single quotes for non-triple-quoted strings.
-quote-style = "single"
-```
-
 For a complete enumeration of the available configuration options, see [_Settings_](settings.md).
 
-## `pyproject.toml` discovery
+## Config file discovery
 
 Similar to [ESLint](https://eslint.org/docs/latest/user-guide/configuring/configuration-files#cascading-and-hierarchy),
-Ruff supports hierarchical configuration, such that the "closest" `pyproject.toml` file in the
-directory hierarchy is used for every individual file, with all paths in the `pyproject.toml` file
+Ruff supports hierarchical configuration, such that the "closest" config file in the
+directory hierarchy is used for every individual file, with all paths in the config file
 (e.g., `exclude` globs, `src` paths) being resolved relative to the directory containing that
-`pyproject.toml` file.
+config file.
 
 There are a few exceptions to these rules:
 
@@ -156,47 +229,69 @@ There are a few exceptions to these rules:
 1. If a configuration file is passed directly via `--config`, those settings are used for _all_
     analyzed files, and any relative paths in that configuration file (like `exclude` globs or
     `src` paths) are resolved relative to the _current_ working directory.
-1. If no `pyproject.toml` file is found in the filesystem hierarchy, Ruff will fall back to using
+1. If no config file is found in the filesystem hierarchy, Ruff will fall back to using
     a default configuration. If a user-specific configuration file exists
     at `${config_dir}/ruff/pyproject.toml`, that file will be used instead of the default
     configuration, with `${config_dir}` being determined via the [`dirs`](https://docs.rs/dirs/4.0.0/dirs/fn.config_dir.html)
     crate, and all relative paths being again resolved relative to the _current working directory_.
-1. Any `pyproject.toml`-supported settings that are provided on the command-line (e.g., via
+1. Any config-file-supported settings that are provided on the command-line (e.g., via
     `--select`) will override the settings in _every_ resolved configuration file.
 
 Unlike [ESLint](https://eslint.org/docs/latest/user-guide/configuring/configuration-files#cascading-and-hierarchy),
 Ruff does not merge settings across configuration files; instead, the "closest" configuration file
 is used, and any parent configuration files are ignored. In lieu of this implicit cascade, Ruff
 supports an [`extend`](settings.md#extend) field, which allows you to inherit the settings from another
-`pyproject.toml` file, like so:
+config file, like so:
 
-```toml
-[tool.ruff]
-# Extend the `pyproject.toml` file in the parent directory...
-extend = "../pyproject.toml"
+=== "pyproject.toml"
 
-# ...but use a different line length.
-line-length = 100
-```
+    ```toml
+    [tool.ruff]
+    # Extend the `pyproject.toml` file in the parent directory...
+    extend = "../pyproject.toml"
 
-All of the above rules apply equivalently to `ruff.toml` and `.ruff.toml` files. If Ruff detects
-multiple configuration files in the same directory, the `.ruff.toml` file will take precedence over
-the `ruff.toml` file, and the `ruff.toml` file will take precedence over the `pyproject.toml` file.
+    # ...but use a different line length.
+    line-length = 100
+    ```
+
+=== "ruff.toml"
+
+    ```toml
+    # Extend the `ruff.toml` file in the parent directory...
+    extend = "../ruff.toml"
+
+    # ...but use a different line length.
+    line-length = 100
+    ```
+
+All of the above rules apply equivalently to `pyproject.toml`, `ruff.toml`, and `.ruff.toml` files.
+If Ruff detects multiple configuration files in the same directory, the `.ruff.toml` file will take
+precedence over the `ruff.toml` file, and the `ruff.toml` file will take precedence over
+the `pyproject.toml` file.
 
 ## Python file discovery
 
 When passed a path on the command-line, Ruff will automatically discover all Python files in that
 path, taking into account the [`exclude`](settings.md#exclude) and [`extend-exclude`](settings.md#extend-exclude)
-settings in each directory's `pyproject.toml` file.
+settings in each directory's configuration file.
 
 Files can also be selectively excluded from linting or formatting by scoping the `exclude` setting
 to the tool-specific configuration tables. For example, the following would prevent `ruff` from
 formatting `.pyi` files, but would continue to include them in linting:
 
-```toml
-[tool.ruff.format]
-exclude = ["*.pyi"]
-```
+=== "pyproject.toml"
+
+    ```toml
+    [tool.ruff.format]
+    exclude = ["*.pyi"]
+    ```
+
+=== "ruff.toml"
+
+    ```toml
+    [format]
+    exclude = ["*.pyi"]
+    ```
 
 By default, Ruff will also skip any files that are omitted via `.ignore`, `.gitignore`,
 `.git/info/exclude`, and global `gitignore` files (see: [`respect-gitignore`](settings.md#respect-gitignore)).
@@ -211,10 +306,18 @@ Ruff has built-in support for [Jupyter Notebooks](https://jupyter.org/).
 To opt in to linting and formatting Jupyter Notebook (`.ipynb`) files, add the `*.ipynb` pattern to
 your [`extend-include`](settings.md#extend-include) setting, like so:
 
-```toml
-[tool.ruff]
-extend-include = ["*.ipynb"]
-```
+=== "pyproject.toml"
+
+    ```toml
+    [tool.ruff]
+    extend-include = ["*.ipynb"]
+    ```
+
+=== "ruff.toml"
+
+    ```toml
+    extend-include = ["*.ipynb"]
+    ```
 
 This will prompt Ruff to discover Jupyter Notebook (`.ipynb`) files in any specified
 directories, then lint and format them accordingly.
@@ -245,10 +348,6 @@ Alternatively, pass the notebook file(s) to `ruff` on the command-line directly.
 `ruff check /path/to/notebook.ipynb` will always lint `notebook.ipynb`. Similarly,
 `ruff format /path/to/notebook.ipynb` will always format `notebook.ipynb`.
 
-All of the above rules apply equivalently to `ruff.toml` and `.ruff.toml` files. If Ruff detects
-multiple configuration files in the same directory, the `.ruff.toml` file will take precedence over
-the `ruff.toml` file, and the `ruff.toml` file will take precedence over the `pyproject.toml` file.
-
 ## Command-line interface
 
 Some configuration options can be provided via the command-line, such as those related to rule
@@ -367,7 +466,7 @@ File selection:
 
 Miscellaneous:
   -n, --no-cache
-          Disable cache reads
+          Disable cache reads [env: RUFF_NO_CACHE=]
       --isolated
           Ignore all configuration files
       --cache-dir <CACHE_DIR>
@@ -414,7 +513,7 @@ Options:
           Print help
 
 Miscellaneous:
-  -n, --no-cache                         Disable cache reads
+  -n, --no-cache                         Disable cache reads [env: RUFF_NO_CACHE=]
       --cache-dir <CACHE_DIR>            Path to the cache directory [env: RUFF_CACHE_DIR=]
       --isolated                         Ignore all configuration files
       --stdin-filename <STDIN_FILENAME>  The name of the file when passing it through stdin

docs/faq.md

@@ -265,24 +265,47 @@ them. You can find the supported settings in the [API reference](settings.md#iso
 For example, you can set [`known-first-party`](settings.md#known-first-party--isort-known-first-party-)
 like so:
 
-```toml
-[tool.ruff.lint]
-select = [
-    # Pyflakes
-    "F",
-    # Pycodestyle
-    "E",
-    "W",
-    # isort
-    "I001"
-]
+=== "pyproject.toml"
 
-# Note: Ruff supports a top-level `src` option in lieu of isort's `src_paths` setting.
-src = ["src", "tests"]
+    ```toml
+    [tool.ruff.lint]
+    select = [
+        # Pyflakes
+        "F",
+        # Pycodestyle
+        "E",
+        "W",
+        # isort
+        "I001"
+    ]
 
-[tool.ruff.lint.isort]
-known-first-party = ["my_module1", "my_module2"]
-```
+    # Note: Ruff supports a top-level `src` option in lieu of isort's `src_paths` setting.
+    src = ["src", "tests"]
+
+    [tool.ruff.lint.isort]
+    known-first-party = ["my_module1", "my_module2"]
+    ```
+
+=== "ruff.toml"
+
+    ```toml
+    [lint]
+    select = [
+        # Pyflakes
+        "F",
+        # Pycodestyle
+        "E",
+        "W",
+        # isort
+        "I001"
+    ]
+
+    # Note: Ruff supports a top-level `src` option in lieu of isort's `src_paths` setting.
+    src = ["src", "tests"]
+
+    [lint.isort]
+    known-first-party = ["my_module1", "my_module2"]
+    ```
 
 ## How does Ruff determine which of my imports are first-party, third-party, etc.?
 
@@ -315,24 +338,42 @@ the `--config` option, in which case, the current working directory is used as t
 In this case, Ruff would only check the top-level directory. Instead, we can configure Ruff to
 consider `src` as a first-party source like so:
 
-```toml
-[tool.ruff]
-# All paths are relative to the project root, which is the directory containing the pyproject.toml.
-src = ["src"]
-```
+=== "pyproject.toml"
+
+    ```toml
+    [tool.ruff]
+    # All paths are relative to the project root, which is the directory containing the pyproject.toml.
+    src = ["src"]
+    ```
+
+=== "ruff.toml"
+
+    ```toml
+    # All paths are relative to the project root, which is the directory containing the pyproject.toml.
+    src = ["src"]
+    ```
 
 If your `pyproject.toml`, `ruff.toml`, or `.ruff.toml` extends another configuration file, Ruff
 will still use the directory containing your `pyproject.toml`, `ruff.toml`, or `.ruff.toml` file as
 the project root (as opposed to the directory of the file pointed to via the `extends` option).
 
-For example, if you add a `ruff.toml` to the `tests` directory in the above example, you'll want to
-explicitly set the `src` option in the extended configuration file:
+For example, if you add a configuration file to the `tests` directory in the above example, you'll
+want to explicitly set the `src` option in the extended configuration file:
 
-```toml
-# tests/ruff.toml
-extend = "../pyproject.toml"
-src = ["../src"]
-```
+=== "pyproject.toml"
+
+    ```toml
+    [tool.ruff]
+    extend = "../pyproject.toml"
+    src = ["../src"]
+    ```
+
+=== "ruff.toml"
+
+    ```toml
+    extend = "../pyproject.toml"
+    src = ["../src"]
+    ```
 
 Beyond this `src`-based detection, Ruff will also attempt to determine the current Python package
 for a given Python file, and mark imports from within the same package as first-party. For example,
@@ -349,10 +390,18 @@ Ruff has built-in support for linting [Jupyter Notebooks](https://jupyter.org/).
 To opt in to linting Jupyter Notebook (`.ipynb`) files, add the `*.ipynb` pattern to your
 [`extend-include`](settings.md#extend-include) setting, like so:
 
-```toml
-[tool.ruff]
-extend-include = ["*.ipynb"]
-```
+=== "pyproject.toml"
+
+    ```toml
+    [tool.ruff]
+    extend-include = ["*.ipynb"]
+    ```
+
+=== "ruff.toml"
+
+    ```toml
+    extend-include = ["*.ipynb"]
+    ```
 
 This will prompt Ruff to discover Jupyter Notebook (`.ipynb`) files in any specified
 directories, then lint and format them accordingly.
@@ -378,12 +427,21 @@ Found 3 errors.
 ## Does Ruff support NumPy- or Google-style docstrings?
 
 Yes! To enforce a docstring convention, add a [`convention`](settings.md#convention--pydocstyle-convention-)
-setting following to your `pyproject.toml`:
+setting following to your configuration file:
 
-```toml
-[tool.ruff.lint.pydocstyle]
-convention = "google"  # Accepts: "google", "numpy", or "pep257".
-```
+=== "pyproject.toml"
+
+    ```toml
+    [tool.ruff.lint.pydocstyle]
+    convention = "google"  # Accepts: "google", "numpy", or "pep257".
+    ```
+
+=== "ruff.toml"
+
+    ```toml
+    [lint.pydocstyle]
+    convention = "google"  # Accepts: "google", "numpy", or "pep257".
+    ```
 
 For example, if you're coming from flake8-docstrings, and your originating configuration uses
 `--docstring-convention=numpy`, you'd instead set `convention = "numpy"` in your `pyproject.toml`,
@@ -392,15 +450,29 @@ as above.
 Alongside [`convention`](settings.md#convention--pydocstyle-convention-), you'll want to
 explicitly enable the `D` rule code prefix, since the `D` rules are not enabled by default:
 
-```toml
-[tool.ruff.lint]
-select = [
-    "D",
-]
+=== "pyproject.toml"
 
-[tool.ruff.lint.pydocstyle]
-convention = "google"
-```
+    ```toml
+    [tool.ruff.lint]
+    select = [
+        "D",
+    ]
+
+    [tool.ruff.lint.pydocstyle]
+    convention = "google"
+    ```
+
+=== "ruff.toml"
+
+    ```toml
+    [lint]
+    select = [
+        "D",
+    ]
+
+    [lint.pydocstyle]
+    convention = "google"
+    ```
 
 Setting a [`convention`](settings.md#convention--pydocstyle-convention-) force-disables any rules
 that are incompatible with that convention, no matter how they're provided, which avoids accidental
@@ -419,11 +491,11 @@ Run `ruff check /path/to/code.py --show-settings` to view the resolved settings
 
 ## I want to use Ruff, but I don't want to use `pyproject.toml`. What are my options?
 
-Yes! In lieu of a `pyproject.toml` file, you can use a `ruff.toml` file for configuration. The two
+In lieu of a `pyproject.toml` file, you can use a `ruff.toml` file for configuration. The two
 files are functionally equivalent and have an identical schema, with the exception that a `ruff.toml`
-file can omit the `[tool.ruff]` section header.
+file can omit the `[tool.ruff]` section header. For example:
 
-For example, given this `pyproject.toml`:
+=== "pyproject.toml"
 
 ```toml
 [tool.ruff]
@@ -433,7 +505,7 @@ line-length = 88
 convention = "google"
 ```
 
-You could instead use a `ruff.toml` file like so:
+=== "ruff.toml"
 
 ```toml
 line-length = 88