Address review comments

## Summary

Pull in https://github.com/hauntsaninja/mypy_primer/pull/169

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,8 +1,9 @@
 <!--
-Thank you for contributing to Ruff! To help us out with reviewing, please consider the following:
+Thank you for contributing to Ruff/ty! To help us out with reviewing, please consider the following:
 
 - Does this pull request include a summary of the change? (See below.)
-- Does this pull request include a descriptive title?
+- Does this pull request include a descriptive title? (Please prefix with `[ty]` for ty pull
+  requests.)
 - Does this pull request include references to any relevant issues?
 -->
 

.github/workflows/mypy_primer.yaml

@@ -69,7 +69,7 @@ jobs:
           echo "Project selector: $PRIMER_SELECTOR"
           # Allow the exit code to be 0 or 1, only fail for actual mypy_primer crashes/bugs
           uvx \
-            --from="git+https://github.com/hauntsaninja/mypy_primer@4b15cf3b07db69db67bbfaebfffb2a8a28040933" \
+            --from="git+https://github.com/hauntsaninja/mypy_primer@968b2b61c05f84462d6fcc78d2f5205bbb8b98c2" \
             mypy_primer \
             --repo ruff \
             --type-checker ty \

CONTRIBUTING.md

@@ -2,6 +2,11 @@
 
 Welcome! We're happy to have you here. Thank you in advance for your contribution to Ruff.
 
+> [!NOTE]
+>
+> This guide is for Ruff. If you're looking to contribute to ty, please see [the ty contributing
+> guide](https://github.com/astral-sh/ruff/blob/main/crates/ty/CONTRIBUTING.md).
+
 ## The Basics
 
 Ruff welcomes contributions in the form of pull requests.

Cargo.lock

@@ -478,7 +478,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "117725a109d387c937a1533ce01b450cbde6b88abceea8473c4d7a85853cda3c"
 dependencies = [
  "lazy_static",
- "windows-sys 0.48.0",
+ "windows-sys 0.59.0",
 ]
 
 [[package]]
@@ -487,7 +487,7 @@ version = "3.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fde0e0ec90c9dfb3b4b1a0891a7dcd0e2bffde2f7efed5fe7c9bb00e5bfb915e"
 dependencies = [
- "windows-sys 0.48.0",
+ "windows-sys 0.59.0",
 ]
 
 [[package]]
@@ -904,7 +904,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "33d852cb9b869c2a9b3df2f71a3074817f01e1844f839a144f5fcef059a4eb5d"
 dependencies = [
  "libc",
- "windows-sys 0.52.0",
+ "windows-sys 0.59.0",
 ]
 
 [[package]]
@@ -1485,7 +1485,7 @@ checksum = "e04d7f318608d35d4b61ddd75cbdaee86b023ebe2bd5a66ee0915f0bf93095a9"
 dependencies = [
  "hermit-abi 0.5.0",
  "libc",
- "windows-sys 0.52.0",
+ "windows-sys 0.59.0",
 ]
 
 [[package]]
@@ -1549,7 +1549,7 @@ dependencies = [
  "portable-atomic",
  "portable-atomic-util",
  "serde",
- "windows-sys 0.52.0",
+ "windows-sys 0.59.0",
 ]
 
 [[package]]
@@ -3231,6 +3231,12 @@ version = "2.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "357703d41365b4b27c590e3ed91eabb1b663f07c4c084095e60cbed4362dff0d"
 
+[[package]]
+name = "rustc-stable-hash"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "781442f29170c5c93b7185ad559492601acdc71d5bb0706f5868094f45cfcd08"
+
 [[package]]
 name = "rustix"
 version = "0.38.44"
@@ -3241,7 +3247,7 @@ dependencies = [
  "errno",
  "libc",
  "linux-raw-sys 0.4.15",
- "windows-sys 0.52.0",
+ "windows-sys 0.59.0",
 ]
 
 [[package]]
@@ -3254,7 +3260,7 @@ dependencies = [
  "errno",
  "libc",
  "linux-raw-sys 0.9.3",
- "windows-sys 0.52.0",
+ "windows-sys 0.59.0",
 ]
 
 [[package]]
@@ -3640,7 +3646,7 @@ dependencies = [
  "getrandom 0.3.3",
  "once_cell",
  "rustix 1.0.2",
- "windows-sys 0.52.0",
+ "windows-sys 0.59.0",
 ]
 
 [[package]]
@@ -4153,6 +4159,7 @@ dependencies = [
  "ruff_source_file",
  "ruff_text_size",
  "rustc-hash 2.1.1",
+ "rustc-stable-hash",
  "salsa",
  "serde",
  "smallvec",
@@ -4638,7 +4645,7 @@ version = "0.1.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cf221c93e13a30d793f7645a0e7762c55d169dbb0a49671918a2319d289b10bb"
 dependencies = [
- "windows-sys 0.48.0",
+ "windows-sys 0.59.0",
 ]
 
 [[package]]

Cargo.toml

@@ -125,6 +125,7 @@ rand = { version = "0.9.0" }
 rayon = { version = "1.10.0" }
 regex = { version = "1.10.2" }
 rustc-hash = { version = "2.0.0" }
+rustc-stable-hash = { version = "0.1.2" }
 # When updating salsa, make sure to also update the revision in `fuzz/Cargo.toml`
 salsa = { git = "https://github.com/salsa-rs/salsa.git", rev = "7edce6e248f35c8114b4b021cdb474a3fb2813b3" }
 schemars = { version = "0.8.16" }

README.md

@@ -255,7 +255,7 @@ indent-width = 4
 target-version = "py39"
 
 [lint]
-# Enable Pyflakes (`F`) and a subset of the pycodestyle (`E`)  codes by default.
+# Enable Pyflakes (`F`) and a subset of the pycodestyle (`E`) codes by default.
 select = ["E4", "E7", "E9", "F"]
 ignore = []
 

crates/ruff_benchmark/benches/ty.rs

@@ -59,40 +59,7 @@ type KeyDiagnosticFields = (
     Severity,
 );
 
-// left: [
-// (Lint(LintName("invalid-argument-type")), Some("/src/tomllib/_parser.py"), Some(8224..8254), "Argument to function `skip_until` is incorrect", Error),
-// (Lint(LintName("invalid-argument-type")), Some("/src/tomllib/_parser.py"), Some(16914..16948), "Argument to function `skip_until` is incorrect", Error),
-// (Lint(LintName("invalid-argument-type")), Some("/src/tomllib/_parser.py"), Some(17319..17363), "Argument to function `skip_until` is incorrect", Error),
-// ]
-//right: [
-// (Lint(LintName("invalid-argument-type")), Some("/src/tomllib/_parser.py"), Some(8224..8254), "Argument to this function is incorrect", Error),
-// (Lint(LintName("invalid-argument-type")), Some("/src/tomllib/_parser.py"), Some(16914..16948), "Argument to this function is incorrect", Error),
-// (Lint(LintName("invalid-argument-type")), Some("/src/tomllib/_parser.py"), Some(17319..17363), "Argument to this function is incorrect", Error),
-// ]
-
-static EXPECTED_TOMLLIB_DIAGNOSTICS: &[KeyDiagnosticFields] = &[
-    (
-        DiagnosticId::lint("invalid-argument-type"),
-        Some("/src/tomllib/_parser.py"),
-        Some(8224..8254),
-        "Argument to function `skip_until` is incorrect",
-        Severity::Error,
-    ),
-    (
-        DiagnosticId::lint("invalid-argument-type"),
-        Some("/src/tomllib/_parser.py"),
-        Some(16914..16948),
-        "Argument to function `skip_until` is incorrect",
-        Severity::Error,
-    ),
-    (
-        DiagnosticId::lint("invalid-argument-type"),
-        Some("/src/tomllib/_parser.py"),
-        Some(17319..17363),
-        "Argument to function `skip_until` is incorrect",
-        Severity::Error,
-    ),
-];
+static EXPECTED_TOMLLIB_DIAGNOSTICS: &[KeyDiagnosticFields] = &[];
 
 fn tomllib_path(file: &TestFile) -> SystemPathBuf {
     SystemPathBuf::from("src").join(file.name())
@@ -334,6 +301,62 @@ fn benchmark_many_string_assignments(criterion: &mut Criterion) {
     });
 }
 
+fn benchmark_many_tuple_assignments(criterion: &mut Criterion) {
+    setup_rayon();
+
+    criterion.bench_function("ty_micro[many_tuple_assignments]", |b| {
+        b.iter_batched_ref(
+            || {
+                // This is a micro benchmark, but it is effectively identical to a code sample
+                // observed in https://github.com/astral-sh/ty/issues/362
+                setup_micro_case(
+                    r#"
+                    def flag() -> bool:
+                        return True
+
+                    t = ()
+                    if flag():
+                        t += (1,)
+                    if flag():
+                        t += (2,)
+                    if flag():
+                        t += (3,)
+                    if flag():
+                        t += (4,)
+                    if flag():
+                        t += (5,)
+                    if flag():
+                        t += (6,)
+                    if flag():
+                        t += (7,)
+                    if flag():
+                        t += (8,)
+                    if flag():
+                        t += (9,)
+                    if flag():
+                        t += (10,)
+                    if flag():
+                        t += (11,)
+
+                    # Perform some kind of operation on the union type
+                    print(1 in t)
+                    "#,
+                )
+            },
+            |case| {
+                let Case { db, .. } = case;
+                let result = db.check().unwrap();
+                assert_eq!(result.len(), 0);
+            },
+            BatchSize::SmallInput,
+        );
+    });
+}
+
 criterion_group!(check_file, benchmark_cold, benchmark_incremental);
-criterion_group!(micro, benchmark_many_string_assignments);
+criterion_group!(
+    micro,
+    benchmark_many_string_assignments,
+    benchmark_many_tuple_assignments
+);
 criterion_main!(check_file, micro);

crates/ruff_dev/src/generate_ty_cli_reference.rs

@@ -179,7 +179,7 @@ fn generate_command<'a>(output: &mut String, command: &'a Command, parents: &mut
                 let id = format!("{name_key}--{}", arg.get_id());
                 output.push_str(&format!("<dt id=\"{id}\">"));
                 output.push_str(&format!(
-                    "<a href=\"#{id}\"<code>{}</code></a>",
+                    "<a href=\"#{id}\"><code>{}</code></a>",
                     arg.get_id().to_string().to_uppercase(),
                 ));
                 output.push_str("</dt>");

crates/ruff_linter/resources/test/fixtures/airflow/AIR301_names.py

@@ -24,9 +24,6 @@ from airflow.contrib.aws_athena_hook import AWSAthenaHook
 from airflow.datasets import DatasetAliasEvent
 from airflow.hooks.base_hook import BaseHook
 from airflow.operators.subdag import SubDagOperator
-from airflow.providers.mysql.datasets import mysql
-from airflow.providers.postgres.datasets import postgres
-from airflow.providers.trino.datasets import trino
 from airflow.secrets.local_filesystem import LocalFilesystemBackend
 from airflow.sensors.base_sensor_operator import BaseSensorOperator
 from airflow.triggers.external_task import TaskStateTrigger
@@ -78,14 +75,6 @@ BaseHook()
 # airflow.operators.subdag.*
 SubDagOperator()
 
-# airflow.providers.mysql
-mysql.sanitize_uri
-
-# airflow.providers.postgres
-postgres.sanitize_uri
-
-# airflow.providers.trino
-trino.sanitize_uri
 
 # airflow.secrets
 # get_connection
@@ -155,3 +144,18 @@ should_hide_value_for_key
 from airflow.operators.python import get_current_context
 
 get_current_context()
+
+# airflow.providers.mysql
+from airflow.providers.mysql.datasets.mysql import sanitize_uri
+
+sanitize_uri
+
+# airflow.providers.postgres
+from airflow.providers.postgres.datasets.postgres import sanitize_uri
+
+sanitize_uri
+
+# airflow.providers.trino
+from airflow.providers.trino.datasets.trino import sanitize_uri
+
+sanitize_uri

crates/ruff_linter/resources/test/fixtures/flake8_pytest_style/PT019.py

@@ -12,3 +12,38 @@ def test_xxx(_fixture):  # Error arg
 
 def test_xxx(*, _fixture):  # Error kwonly
     pass
+
+# https://github.com/astral-sh/ruff/issues/17599
+
+@pytest.mark.parametrize("_foo", [1, 2, 3])
+def test_thingy(_foo):  # Ok defined in parametrize
+    pass
+
+@pytest.mark.parametrize(
+    "_test_input,_expected",
+    [("3+5", 8), ("2+4", 6), pytest.param("6*9", 42, marks=pytest.mark.xfail)],
+)
+def test_eval(_test_input, _expected):  # OK defined in parametrize
+    pass
+
+
+@pytest.mark.parametrize("_foo", [1, 2, 3])
+def test_thingy2(_foo, _bar):  # Error _bar is not defined in parametrize
+    pass
+
+@pytest.mark.parametrize(["_foo", "_bar"], [1, 2, 3])
+def test_thingy3(_foo, _bar):  # OK defined in parametrize
+    pass
+
+@pytest.mark.parametrize(("_foo"), [1, 2, 3])
+def test_thingy4(_foo, _bar):  # Error _bar is not defined in parametrize
+    pass
+
+@pytest.mark.parametrize(["   _foo", "   _bar    "], [1, 2, 3])
+def test_thingy5(_foo, _bar):  # OK defined in parametrize
+    pass
+
+x = "other"
+@pytest.mark.parametrize(x, [1, 2, 3])
+def test_thingy5(_foo, _bar):  # known false negative, we don't try to resolve variables
+    pass

crates/ruff_linter/resources/test/fixtures/flake8_simplify/SIM905.py

@@ -110,3 +110,23 @@ b"TesT.WwW.ExamplE.CoM".split(b".")
 # https://github.com/astral-sh/ruff/issues/18042
 print("a,b".rsplit(","))
 print("a,b,c".rsplit(",", 1))
+
+# https://github.com/astral-sh/ruff/issues/18069
+
+print("".split(maxsplit=0))
+print("".split(sep=None, maxsplit=0))
+print(" ".split(maxsplit=0))
+print(" ".split(sep=None, maxsplit=0))
+print(" x ".split(maxsplit=0))
+print(" x ".split(sep=None, maxsplit=0))
+print("  x  ".split(maxsplit=0))
+print("  x  ".split(sep=None, maxsplit=0))
+print("".rsplit(maxsplit=0))
+print("".rsplit(sep=None, maxsplit=0))
+print(" ".rsplit(maxsplit=0))
+print(" ".rsplit(sep=None, maxsplit=0))
+print(" x ".rsplit(maxsplit=0))
+print(" x ".rsplit(maxsplit=0))
+print(" x ".rsplit(sep=None, maxsplit=0))
+print("  x  ".rsplit(maxsplit=0))
+print("  x  ".rsplit(sep=None, maxsplit=0))

crates/ruff_linter/resources/test/fixtures/pyupgrade/UP024_2.py

@@ -6,14 +6,16 @@ from .mmap import error
 raise error
 
 # Testing the modules
-import socket, mmap, select
+import socket, mmap, select, resource
 raise socket.error
 raise mmap.error
 raise select.error
+raise resource.error
 
 raise socket.error()
 raise mmap.error(1)
 raise select.error(1, 2)
+raise resource.error(1, "strerror", "filename")
 
 raise socket.error(
     1,
@@ -30,6 +32,9 @@ raise error(1)
 from select import error
 raise error(1, 2)
 
+from resource import error
+raise error(1, "strerror", "filename")
+
 # Testing the names
 raise EnvironmentError
 raise IOError

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

@@ -8,13 +8,20 @@ use ruff_python_semantic::SemanticModel;
 
 #[derive(Clone, Debug, Eq, PartialEq)]
 pub(crate) enum Replacement {
+    // There's no replacement or suggestion other than removal
     None,
-    Name(&'static str),
+    // The attribute name of a class has been changed.
+    AttrName(&'static str),
+    // Additional information. Used when there's replacement but they're not direct mapping.
     Message(&'static str),
+    // Symbols updated in Airflow 3 with replacement
+    // e.g., `airflow.datasets.Dataset` to `airflow.sdk.Asset`
     AutoImport {
         module: &'static str,
         name: &'static str,
     },
+    // Symbols updated in Airflow 3 with only module changed. Used when we want to match multiple names.
+    // e.g., `airflow.configuration.as_dict | get` to `airflow.configuration.conf.as_dict | get`
     SourceModuleMoved {
         module: &'static str,
         name: String,

crates/ruff_linter/src/rules/airflow/rules/removal_in_3.rs

@@ -57,28 +57,27 @@ impl Violation for Airflow3Removal {
         } = self;
         match replacement {
             Replacement::None
-            | Replacement::Name(_)
+            | Replacement::AttrName(_)
+            | Replacement::Message(_)
             | Replacement::AutoImport { module: _, name: _ }
             | Replacement::SourceModuleMoved { module: _, name: _ } => {
                 format!("`{deprecated}` is removed in Airflow 3.0")
             }
-            Replacement::Message(message) => {
-                format!("`{deprecated}` is removed in Airflow 3.0; {message}")
-            }
         }
     }
 
     fn fix_title(&self) -> Option<String> {
         let Airflow3Removal { replacement, .. } = self;
         match replacement {
-            Replacement::Name(name) => Some(format!("Use `{name}` instead")),
+            Replacement::None => None,
+            Replacement::AttrName(name) => Some(format!("Use `{name}` instead")),
+            Replacement::Message(message) => Some((*message).to_string()),
             Replacement::AutoImport { module, name } => {
                 Some(format!("Use `{module}.{name}` instead"))
             }
             Replacement::SourceModuleMoved { module, name } => {
                 Some(format!("Use `{module}.{name}` instead"))
             }
-            _ => None,
         }
     }
 }
@@ -278,22 +277,22 @@ fn check_class_attribute(checker: &Checker, attribute_expr: &ExprAttribute) {
 
     let replacement = match *qualname.segments() {
         ["airflow", "providers_manager", "ProvidersManager"] => match attr.as_str() {
-            "dataset_factories" => Replacement::Name("asset_factories"),
-            "dataset_uri_handlers" => Replacement::Name("asset_uri_handlers"),
+            "dataset_factories" => Replacement::AttrName("asset_factories"),
+            "dataset_uri_handlers" => Replacement::AttrName("asset_uri_handlers"),
             "dataset_to_openlineage_converters" => {
-                Replacement::Name("asset_to_openlineage_converters")
+                Replacement::AttrName("asset_to_openlineage_converters")
             }
             _ => return,
         },
         ["airflow", "lineage", "hook", "DatasetLineageInfo"] => match attr.as_str() {
-            "dataset" => Replacement::Name("asset"),
+            "dataset" => Replacement::AttrName("asset"),
             _ => return,
         },
         _ => return,
     };
 
     // Create the `Fix` first to avoid cloning `Replacement`.
-    let fix = if let Replacement::Name(name) = replacement {
+    let fix = if let Replacement::AttrName(name) = replacement {
         Some(Fix::safe_edit(Edit::range_replacement(
             name.to_string(),
             attr.range(),
@@ -466,52 +465,52 @@ fn check_method(checker: &Checker, call_expr: &ExprCall) {
 
     let replacement = match qualname.segments() {
         ["airflow", "datasets", "manager", "DatasetManager"] => match attr.as_str() {
-            "register_dataset_change" => Replacement::Name("register_asset_change"),
-            "create_datasets" => Replacement::Name("create_assets"),
-            "notify_dataset_created" => Replacement::Name("notify_asset_created"),
-            "notify_dataset_changed" => Replacement::Name("notify_asset_changed"),
-            "notify_dataset_alias_created" => Replacement::Name("notify_asset_alias_created"),
+            "register_dataset_change" => Replacement::AttrName("register_asset_change"),
+            "create_datasets" => Replacement::AttrName("create_assets"),
+            "notify_dataset_created" => Replacement::AttrName("notify_asset_created"),
+            "notify_dataset_changed" => Replacement::AttrName("notify_asset_changed"),
+            "notify_dataset_alias_created" => Replacement::AttrName("notify_asset_alias_created"),
             _ => return,
         },
         ["airflow", "lineage", "hook", "HookLineageCollector"] => match attr.as_str() {
-            "create_dataset" => Replacement::Name("create_asset"),
-            "add_input_dataset" => Replacement::Name("add_input_asset"),
-            "add_output_dataset" => Replacement::Name("add_output_asset"),
-            "collected_datasets" => Replacement::Name("collected_assets"),
+            "create_dataset" => Replacement::AttrName("create_asset"),
+            "add_input_dataset" => Replacement::AttrName("add_input_asset"),
+            "add_output_dataset" => Replacement::AttrName("add_output_asset"),
+            "collected_datasets" => Replacement::AttrName("collected_assets"),
             _ => return,
         },
         ["airflow", "providers", "amazon", "auth_manager", "aws_auth_manager", "AwsAuthManager"] => {
             match attr.as_str() {
-                "is_authorized_dataset" => Replacement::Name("is_authorized_asset"),
+                "is_authorized_dataset" => Replacement::AttrName("is_authorized_asset"),
                 _ => return,
             }
         }
         ["airflow", "providers_manager", "ProvidersManager"] => match attr.as_str() {
             "initialize_providers_dataset_uri_resources" => {
-                Replacement::Name("initialize_providers_asset_uri_resources")
+                Replacement::AttrName("initialize_providers_asset_uri_resources")
             }
             _ => return,
         },
         ["airflow", "secrets", "local_filesystem", "LocalFilesystemBackend"] => match attr.as_str()
         {
-            "get_connections" => Replacement::Name("get_connection"),
+            "get_connections" => Replacement::AttrName("get_connection"),
             _ => return,
         },
         ["airflow", "datasets", ..] | ["airflow", "Dataset"] => match attr.as_str() {
-            "iter_datasets" => Replacement::Name("iter_assets"),
-            "iter_dataset_aliases" => Replacement::Name("iter_asset_aliases"),
+            "iter_datasets" => Replacement::AttrName("iter_assets"),
+            "iter_dataset_aliases" => Replacement::AttrName("iter_asset_aliases"),
             _ => return,
         },
         segments => {
             if is_airflow_secret_backend(segments) {
                 match attr.as_str() {
-                    "get_conn_uri" => Replacement::Name("get_conn_value"),
-                    "get_connections" => Replacement::Name("get_connection"),
+                    "get_conn_uri" => Replacement::AttrName("get_conn_value"),
+                    "get_connections" => Replacement::AttrName("get_connection"),
                     _ => return,
                 }
             } else if is_airflow_hook(segments) {
                 match attr.as_str() {
-                    "get_connections" => Replacement::Name("get_connection"),
+                    "get_connections" => Replacement::AttrName("get_connection"),
                     _ => return,
                 }
             } else {
@@ -520,7 +519,7 @@ fn check_method(checker: &Checker, call_expr: &ExprCall) {
         }
     };
     // Create the `Fix` first to avoid cloning `Replacement`.
-    let fix = if let Replacement::Name(name) = replacement {
+    let fix = if let Replacement::AttrName(name) = replacement {
         Some(Fix::safe_edit(Edit::range_replacement(
             name.to_string(),
             attr.range(),
@@ -566,12 +565,12 @@ fn check_name(checker: &Checker, expr: &Expr, range: TextRange) {
     let replacement = match qualified_name.segments() {
         // airflow.PY\d{1,2}
         ["airflow", "PY36" | "PY37" | "PY38" | "PY39" | "PY310" | "PY311" | "PY312"] => {
-            Replacement::Name("sys.version_info")
+            Replacement::Message("Use `sys.version_info` instead")
         }
 
         // airflow.api_connexion.security
         ["airflow", "api_connexion", "security", "requires_access"] => {
-            Replacement::Name("airflow.api_connexion.security.requires_access_*")
+            Replacement::Message("Use `airflow.api_connexion.security.requires_access_*` instead")
         }
         ["airflow", "api_connexion", "security", "requires_access_dataset"] => {
             Replacement::AutoImport {
@@ -626,9 +625,10 @@ fn check_name(checker: &Checker, expr: &Expr, range: TextRange) {
         ["airflow", "datasets", "DatasetAliasEvent"] => Replacement::None,
 
         // airflow.hooks
-        ["airflow", "hooks", "base_hook", "BaseHook"] => {
-            Replacement::Name("airflow.hooks.base.BaseHook")
-        }
+        ["airflow", "hooks", "base_hook", "BaseHook"] => Replacement::AutoImport {
+            module: "airflow.hooks.base",
+            name: "BaseHook",
+        },
 
         // airflow.lineage.hook
         ["airflow", "lineage", "hook", "DatasetLineageInfo"] => Replacement::AutoImport {
@@ -664,9 +664,10 @@ fn check_name(checker: &Checker, expr: &Expr, range: TextRange) {
         },
 
         // airflow.notifications
-        ["airflow", "notifications", "basenotifier", "BaseNotifier"] => {
-            Replacement::Name("airflow.sdk.BaseNotifier")
-        }
+        ["airflow", "notifications", "basenotifier", "BaseNotifier"] => Replacement::AutoImport {
+            module: "airflow.sdk",
+            name: "BaseNotifier",
+        },
 
         // airflow.operators
         ["airflow", "operators", "subdag", ..] => {
@@ -691,7 +692,10 @@ fn check_name(checker: &Checker, expr: &Expr, range: TextRange) {
 
         // airflow.sensors
         ["airflow", "sensors", "base_sensor_operator", "BaseSensorOperator"] => {
-            Replacement::Name("airflow.sdk.bases.sensor.BaseSensorOperator")
+            Replacement::AutoImport {
+                module: "airflow.sdk.bases.sensor",
+                name: "BaseSensorOperator",
+            }
         }
 
         // airflow.timetables
@@ -720,23 +724,36 @@ fn check_name(checker: &Checker, expr: &Expr, range: TextRange) {
 
             // airflow.utils.dates
             ["dates", "date_range"] => Replacement::None,
-            ["dates", "days_ago"] => Replacement::Name("pendulum.today('UTC').add(days=-N, ...)"),
+            ["dates", "days_ago"] => {
+                Replacement::Message("Use `pendulum.today('UTC').add(days=-N, ...)` instead")
+            }
             ["dates", "parse_execution_date" | "round_time" | "scale_time_units" | "infer_time_unit"] => {
                 Replacement::None
             }
 
             // airflow.utils.file
-            ["file", "TemporaryDirectory"] => Replacement::Name("tempfile.TemporaryDirectory"),
-            ["file", "mkdirs"] => Replacement::Name("pathlib.Path({path}).mkdir"),
+            ["file", "TemporaryDirectory"] => Replacement::AutoImport {
+                module: "tempfile",
+                name: "TemporaryDirectory",
+            },
+            ["file", "mkdirs"] => Replacement::Message("Use `pathlib.Path({path}).mkdir` instead"),
 
             // airflow.utils.helpers
-            ["helpers", "chain"] => Replacement::Name("airflow.sdk.chain"),
-            ["helpers", "cross_downstream"] => Replacement::Name("airflow.sdk.cross_downstream"),
+            ["helpers", "chain"] => Replacement::AutoImport {
+                module: "airflow.sdk",
+                name: "chain",
+            },
+            ["helpers", "cross_downstream"] => Replacement::AutoImport {
+                module: "airflow.sdk",
+                name: "cross_downstream",
+            },
 
+            // TODO: update it as SourceModuleMoved
             // airflow.utils.log.secrets_masker
-            ["log", "secrets_masker"] => {
-                Replacement::Name("airflow.sdk.execution_time.secrets_masker")
-            }
+            ["log", "secrets_masker"] => Replacement::AutoImport {
+                module: "airflow.sdk.execution_time",
+                name: "secrets_masker",
+            },
 
             // airflow.utils.state
             ["state", "SHUTDOWN" | "terminating_states"] => Replacement::None,
@@ -751,18 +768,20 @@ fn check_name(checker: &Checker, expr: &Expr, range: TextRange) {
         // airflow.www
         // TODO: www has been removed
         ["airflow", "www", "auth", "has_access"] => {
-            Replacement::Name("airflow.www.auth.has_access_*")
+            Replacement::Message("Use `airflow.www.auth.has_access_*` instead")
         }
         ["airflow", "www", "auth", "has_access_dataset"] => Replacement::AutoImport {
             module: "airflow.www.auth",
             name: "has_access_asset",
         },
-        ["airflow", "www", "utils", "get_sensitive_variables_fields"] => {
-            Replacement::Name("airflow.utils.log.secrets_masker.get_sensitive_variables_fields")
-        }
-        ["airflow", "www", "utils", "should_hide_value_for_key"] => {
-            Replacement::Name("airflow.utils.log.secrets_masker.should_hide_value_for_key")
-        }
+        ["airflow", "www", "utils", "get_sensitive_variables_fields"] => Replacement::AutoImport {
+            module: "airflow.utils.log.secrets_masker",
+            name: "get_sensitive_variables_fields",
+        },
+        ["airflow", "www", "utils", "should_hide_value_for_key"] => Replacement::AutoImport {
+            module: "airflow.utils.log.secrets_masker",
+            name: "should_hide_value_for_key",
+        },
 
         // airflow.providers.amazon
         ["airflow", "providers", "amazon", "aws", "datasets", "s3", rest] => match *rest {
@@ -774,9 +793,10 @@ fn check_name(checker: &Checker, expr: &Expr, range: TextRange) {
                 module: "airflow.providers.amazon.aws.assets.s3",
                 name: "convert_asset_to_openlineage",
             },
-            "sanitize_uri" => {
-                Replacement::Name("airflow.providers.amazon.aws.assets.s3.sanitize_uri")
-            }
+            "sanitize_uri" => Replacement::AutoImport {
+                module: "airflow.providers.amazon.aws.assets.s3",
+                name: "sanitize_uri",
+            },
             _ => return,
         },
         ["airflow", "providers", "amazon", "aws", "auth_manager", "avp", "entities", "AvpEntities", "DATASET"] => {
@@ -797,9 +817,10 @@ fn check_name(checker: &Checker, expr: &Expr, range: TextRange) {
                 module: "airflow.providers.common.io.assets.file",
                 name: "convert_asset_to_openlineage",
             },
-            "sanitize_uri" => {
-                Replacement::Name("airflow.providers.common.io.assets.file.sanitize_uri")
-            }
+            "sanitize_uri" => Replacement::AutoImport {
+                module: "airflow.providers.common.io.assets.file",
+                name: "sanitize_uri",
+            },
             _ => return,
         },
 
@@ -826,20 +847,28 @@ fn check_name(checker: &Checker, expr: &Expr, range: TextRange) {
                 module: "airflow.providers.google.assets.gcs",
                 name: "convert_asset_to_openlineage",
             },
-            ["gcs", "sanitize_uri"] => {
-                Replacement::Name("airflow.providers.google.assets.gcs.sanitize_uri")
-            }
+            ["gcs", "sanitize_uri"] => Replacement::AutoImport {
+                module: "airflow.providers.google.assets.gcs",
+                name: "sanitize_uri",
+            },
+
             _ => return,
         },
 
         // airflow.providers.mysql
         ["airflow", "providers", "mysql", "datasets", "mysql", "sanitize_uri"] => {
-            Replacement::Name("airflow.providers.mysql.assets.mysql.sanitize_uri")
+            Replacement::AutoImport {
+                module: "airflow.providers.mysql.assets.mysql",
+                name: "sanitize_uri",
+            }
         }
 
         // airflow.providers.postgres
         ["airflow", "providers", "postgres", "datasets", "postgres", "sanitize_uri"] => {
-            Replacement::Name("airflow.providers.postgres.assets.postgres.sanitize_uri")
+            Replacement::AutoImport {
+                module: "airflow.providers.postgres.assets.postgres",
+                name: "sanitize_uri",
+            }
         }
 
         // airflow.providers.openlineage
@@ -859,7 +888,10 @@ fn check_name(checker: &Checker, expr: &Expr, range: TextRange) {
 
         // airflow.providers.trino
         ["airflow", "providers", "trino", "datasets", "trino", "sanitize_uri"] => {
-            Replacement::Name("airflow.providers.trino.assets.trino.sanitize_uri")
+            Replacement::AutoImport {
+                module: "airflow.providers.trino.assets.trino",
+                name: "sanitize_uri",
+            }
         }
 
         _ => return,
@@ -949,7 +981,7 @@ fn diagnostic_for_argument(
         Airflow3Removal {
             deprecated: deprecated.to_string(),
             replacement: match replacement {
-                Some(name) => Replacement::Name(name),
+                Some(name) => Replacement::AttrName(name),
                 None => Replacement::None,
             },
         },

crates/ruff_linter/src/rules/airflow/rules/suggested_to_update_3_0.rs

@@ -53,7 +53,8 @@ impl Violation for Airflow3SuggestedUpdate {
         } = self;
         match replacement {
             Replacement::None
-            | Replacement::Name(_)
+            | Replacement::AttrName(_)
+            | Replacement::Message(_)
             | Replacement::AutoImport { module: _, name: _ }
             | Replacement::SourceModuleMoved { module: _, name: _ } => {
                 format!(
@@ -61,27 +62,21 @@ impl Violation for Airflow3SuggestedUpdate {
                     It still works in Airflow 3.0 but is expected to be removed in a future version."
                 )
             }
-            Replacement::Message(message) => {
-                format!(
-                    "`{deprecated}` is removed in Airflow 3.0; \
-                     It still works in Airflow 3.0 but is expected to be removed in a future version.; \
-                    {message}"
-                )
-            }
         }
     }
 
     fn fix_title(&self) -> Option<String> {
         let Airflow3SuggestedUpdate { replacement, .. } = self;
         match replacement {
-            Replacement::Name(name) => Some(format!("Use `{name}` instead")),
+            Replacement::None => None,
+            Replacement::AttrName(name) => Some(format!("Use `{name}` instead")),
+            Replacement::Message(message) => Some((*message).to_string()),
             Replacement::AutoImport { module, name } => {
                 Some(format!("Use `{module}.{name}` instead"))
             }
             Replacement::SourceModuleMoved { module, name } => {
                 Some(format!("Use `{module}.{name}` instead"))
             }
-            _ => None,
         }
     }
 }
@@ -126,7 +121,7 @@ fn diagnostic_for_argument(
         Airflow3SuggestedUpdate {
             deprecated: deprecated.to_string(),
             replacement: match replacement {
-                Some(name) => Replacement::Name(name),
+                Some(name) => Replacement::AttrName(name),
                 None => Replacement::None,
             },
         },

crates/ruff_linter/src/rules/airflow/snapshots/ruff_linter__rules__airflow__tests__AIR301_AIR301_airflow_plugin.py.snap

@@ -1,7 +1,7 @@
 ---
 source: crates/ruff_linter/src/rules/airflow/mod.rs
 ---
-AIR301_airflow_plugin.py:7:5: AIR301 `operators` is removed in Airflow 3.0; This extension should just be imported as a regular python module.
+AIR301_airflow_plugin.py:7:5: AIR301 `operators` is removed in Airflow 3.0
   |
 5 |     name = "test_plugin"
 6 |     # --- Invalid extensions start
@@ -10,8 +10,9 @@ AIR301_airflow_plugin.py:7:5: AIR301 `operators` is removed in Airflow 3.0; This
 8 |     sensors = [PluginSensorOperator]
 9 |     hooks = [PluginHook]
   |
+  = help: This extension should just be imported as a regular python module.
 
-AIR301_airflow_plugin.py:8:5: AIR301 `sensors` is removed in Airflow 3.0; This extension should just be imported as a regular python module.
+AIR301_airflow_plugin.py:8:5: AIR301 `sensors` is removed in Airflow 3.0
    |
  6 |     # --- Invalid extensions start
  7 |     operators = [PluginOperator]
@@ -20,8 +21,9 @@ AIR301_airflow_plugin.py:8:5: AIR301 `sensors` is removed in Airflow 3.0; This e
  9 |     hooks = [PluginHook]
 10 |     executors = [PluginExecutor]
    |
+   = help: This extension should just be imported as a regular python module.
 
-AIR301_airflow_plugin.py:9:5: AIR301 `hooks` is removed in Airflow 3.0; This extension should just be imported as a regular python module.
+AIR301_airflow_plugin.py:9:5: AIR301 `hooks` is removed in Airflow 3.0
    |
  7 |     operators = [PluginOperator]
  8 |     sensors = [PluginSensorOperator]
@@ -30,8 +32,9 @@ AIR301_airflow_plugin.py:9:5: AIR301 `hooks` is removed in Airflow 3.0; This ext
 10 |     executors = [PluginExecutor]
 11 |     # --- Invalid extensions end
    |
+   = help: This extension should just be imported as a regular python module.
 
-AIR301_airflow_plugin.py:10:5: AIR301 `executors` is removed in Airflow 3.0; This extension should just be imported as a regular python module.
+AIR301_airflow_plugin.py:10:5: AIR301 `executors` is removed in Airflow 3.0
    |
  8 |     sensors = [PluginSensorOperator]
  9 |     hooks = [PluginHook]
@@ -40,3 +43,4 @@ AIR301_airflow_plugin.py:10:5: AIR301 `executors` is removed in Airflow 3.0; Thi
 11 |     # --- Invalid extensions end
 12 |     macros = [plugin_macro]
    |
+   = help: This extension should just be imported as a regular python module.

crates/ruff_linter/src/rules/airflow/snapshots/ruff_linter__rules__airflow__tests__AIR301_AIR301_args.py.snap

@@ -258,10 +258,11 @@ AIR301_args.py:90:16: AIR301 `filename_template` is removed in Airflow 3.0
 92 | FabAuthManager(None)
    |
 
-AIR301_args.py:92:15: AIR301 `appbuilder` is removed in Airflow 3.0; The constructor takes no parameter now
+AIR301_args.py:92:15: AIR301 `appbuilder` is removed in Airflow 3.0
    |
 90 | GCSTaskHandler(filename_template="/tmp/test")
 91 |
 92 | FabAuthManager(None)
    |               ^^^^^^ AIR301
    |
+   = help: The constructor takes no parameter now

crates/ruff_linter/src/rules/airflow/snapshots/ruff_linter__rules__airflow__tests__AIR301_AIR301_names.py.snap

@@ -1,448 +1,488 @@
 ---
 source: crates/ruff_linter/src/rules/airflow/mod.rs
 ---
-AIR301_names.py:56:1: AIR301 `airflow.PY36` is removed in Airflow 3.0
+AIR301_names.py:53:1: AIR301 `airflow.PY36` is removed in Airflow 3.0
    |
-55 | # airflow root
-56 | PY36, PY37, PY38, PY39, PY310, PY311, PY312
+52 | # airflow root
+53 | PY36, PY37, PY38, PY39, PY310, PY311, PY312
    | ^^^^ AIR301
-57 |
-58 | # airflow.api_connexion.security
+54 |
+55 | # airflow.api_connexion.security
    |
    = help: Use `sys.version_info` instead
 
-AIR301_names.py:56:7: AIR301 `airflow.PY37` is removed in Airflow 3.0
+AIR301_names.py:53:7: AIR301 `airflow.PY37` is removed in Airflow 3.0
    |
-55 | # airflow root
-56 | PY36, PY37, PY38, PY39, PY310, PY311, PY312
+52 | # airflow root
+53 | PY36, PY37, PY38, PY39, PY310, PY311, PY312
    |       ^^^^ AIR301
-57 |
-58 | # airflow.api_connexion.security
+54 |
+55 | # airflow.api_connexion.security
    |
    = help: Use `sys.version_info` instead
 
-AIR301_names.py:56:13: AIR301 `airflow.PY38` is removed in Airflow 3.0
+AIR301_names.py:53:13: AIR301 `airflow.PY38` is removed in Airflow 3.0
    |
-55 | # airflow root
-56 | PY36, PY37, PY38, PY39, PY310, PY311, PY312
+52 | # airflow root
+53 | PY36, PY37, PY38, PY39, PY310, PY311, PY312
    |             ^^^^ AIR301
-57 |
-58 | # airflow.api_connexion.security
+54 |
+55 | # airflow.api_connexion.security
    |
    = help: Use `sys.version_info` instead
 
-AIR301_names.py:56:19: AIR301 `airflow.PY39` is removed in Airflow 3.0
+AIR301_names.py:53:19: AIR301 `airflow.PY39` is removed in Airflow 3.0
    |
-55 | # airflow root
-56 | PY36, PY37, PY38, PY39, PY310, PY311, PY312
+52 | # airflow root
+53 | PY36, PY37, PY38, PY39, PY310, PY311, PY312
    |                   ^^^^ AIR301
-57 |
-58 | # airflow.api_connexion.security
+54 |
+55 | # airflow.api_connexion.security
    |
    = help: Use `sys.version_info` instead
 
-AIR301_names.py:56:25: AIR301 `airflow.PY310` is removed in Airflow 3.0
+AIR301_names.py:53:25: AIR301 `airflow.PY310` is removed in Airflow 3.0
    |
-55 | # airflow root
-56 | PY36, PY37, PY38, PY39, PY310, PY311, PY312
+52 | # airflow root
+53 | PY36, PY37, PY38, PY39, PY310, PY311, PY312
    |                         ^^^^^ AIR301
-57 |
-58 | # airflow.api_connexion.security
+54 |
+55 | # airflow.api_connexion.security
    |
    = help: Use `sys.version_info` instead
 
-AIR301_names.py:56:32: AIR301 `airflow.PY311` is removed in Airflow 3.0
+AIR301_names.py:53:32: AIR301 `airflow.PY311` is removed in Airflow 3.0
    |
-55 | # airflow root
-56 | PY36, PY37, PY38, PY39, PY310, PY311, PY312
+52 | # airflow root
+53 | PY36, PY37, PY38, PY39, PY310, PY311, PY312
    |                                ^^^^^ AIR301
-57 |
-58 | # airflow.api_connexion.security
+54 |
+55 | # airflow.api_connexion.security
    |
    = help: Use `sys.version_info` instead
 
-AIR301_names.py:56:39: AIR301 `airflow.PY312` is removed in Airflow 3.0
+AIR301_names.py:53:39: AIR301 `airflow.PY312` is removed in Airflow 3.0
    |
-55 | # airflow root
-56 | PY36, PY37, PY38, PY39, PY310, PY311, PY312
+52 | # airflow root
+53 | PY36, PY37, PY38, PY39, PY310, PY311, PY312
    |                                       ^^^^^ AIR301
-57 |
-58 | # airflow.api_connexion.security
+54 |
+55 | # airflow.api_connexion.security
    |
    = help: Use `sys.version_info` instead
 
-AIR301_names.py:59:1: AIR301 `airflow.api_connexion.security.requires_access` is removed in Airflow 3.0
+AIR301_names.py:56:1: AIR301 `airflow.api_connexion.security.requires_access` is removed in Airflow 3.0
    |
-58 | # airflow.api_connexion.security
-59 | requires_access
+55 | # airflow.api_connexion.security
+56 | requires_access
    | ^^^^^^^^^^^^^^^ AIR301
    |
    = help: Use `airflow.api_connexion.security.requires_access_*` instead
 
-AIR301_names.py:63:1: AIR301 `airflow.configuration.get` is removed in Airflow 3.0
+AIR301_names.py:60:1: AIR301 `airflow.configuration.get` is removed in Airflow 3.0
    |
-62 | # airflow.configuration
-63 | get, getboolean, getfloat, getint, has_option, remove_option, as_dict, set
+59 | # airflow.configuration
+60 | get, getboolean, getfloat, getint, has_option, remove_option, as_dict, set
    | ^^^ AIR301
    |
    = help: Use `airflow.configuration.conf.get` instead
 
-AIR301_names.py:63:6: AIR301 `airflow.configuration.getboolean` is removed in Airflow 3.0
+AIR301_names.py:60:6: AIR301 `airflow.configuration.getboolean` is removed in Airflow 3.0
    |
-62 | # airflow.configuration
-63 | get, getboolean, getfloat, getint, has_option, remove_option, as_dict, set
+59 | # airflow.configuration
+60 | get, getboolean, getfloat, getint, has_option, remove_option, as_dict, set
    |      ^^^^^^^^^^ AIR301
    |
    = help: Use `airflow.configuration.conf.getboolean` instead
 
-AIR301_names.py:63:18: AIR301 `airflow.configuration.getfloat` is removed in Airflow 3.0
+AIR301_names.py:60:18: AIR301 `airflow.configuration.getfloat` is removed in Airflow 3.0
    |
-62 | # airflow.configuration
-63 | get, getboolean, getfloat, getint, has_option, remove_option, as_dict, set
+59 | # airflow.configuration
+60 | get, getboolean, getfloat, getint, has_option, remove_option, as_dict, set
    |                  ^^^^^^^^ AIR301
    |
    = help: Use `airflow.configuration.conf.getfloat` instead
 
-AIR301_names.py:63:28: AIR301 `airflow.configuration.getint` is removed in Airflow 3.0
+AIR301_names.py:60:28: AIR301 `airflow.configuration.getint` is removed in Airflow 3.0
    |
-62 | # airflow.configuration
-63 | get, getboolean, getfloat, getint, has_option, remove_option, as_dict, set
+59 | # airflow.configuration
+60 | get, getboolean, getfloat, getint, has_option, remove_option, as_dict, set
    |                            ^^^^^^ AIR301
    |
    = help: Use `airflow.configuration.conf.getint` instead
 
-AIR301_names.py:63:36: AIR301 `airflow.configuration.has_option` is removed in Airflow 3.0
+AIR301_names.py:60:36: AIR301 `airflow.configuration.has_option` is removed in Airflow 3.0
    |
-62 | # airflow.configuration
-63 | get, getboolean, getfloat, getint, has_option, remove_option, as_dict, set
+59 | # airflow.configuration
+60 | get, getboolean, getfloat, getint, has_option, remove_option, as_dict, set
    |                                    ^^^^^^^^^^ AIR301
    |
    = help: Use `airflow.configuration.conf.has_option` instead
 
-AIR301_names.py:63:48: AIR301 `airflow.configuration.remove_option` is removed in Airflow 3.0
+AIR301_names.py:60:48: AIR301 `airflow.configuration.remove_option` is removed in Airflow 3.0
    |
-62 | # airflow.configuration
-63 | get, getboolean, getfloat, getint, has_option, remove_option, as_dict, set
+59 | # airflow.configuration
+60 | get, getboolean, getfloat, getint, has_option, remove_option, as_dict, set
    |                                                ^^^^^^^^^^^^^ AIR301
    |
    = help: Use `airflow.configuration.conf.remove_option` instead
 
-AIR301_names.py:63:63: AIR301 `airflow.configuration.as_dict` is removed in Airflow 3.0
+AIR301_names.py:60:63: AIR301 `airflow.configuration.as_dict` is removed in Airflow 3.0
    |
-62 | # airflow.configuration
-63 | get, getboolean, getfloat, getint, has_option, remove_option, as_dict, set
+59 | # airflow.configuration
+60 | get, getboolean, getfloat, getint, has_option, remove_option, as_dict, set
    |                                                               ^^^^^^^ AIR301
    |
    = help: Use `airflow.configuration.conf.as_dict` instead
 
-AIR301_names.py:63:72: AIR301 `airflow.configuration.set` is removed in Airflow 3.0
+AIR301_names.py:60:72: AIR301 `airflow.configuration.set` is removed in Airflow 3.0
    |
-62 | # airflow.configuration
-63 | get, getboolean, getfloat, getint, has_option, remove_option, as_dict, set
+59 | # airflow.configuration
+60 | get, getboolean, getfloat, getint, has_option, remove_option, as_dict, set
    |                                                                        ^^^ AIR301
    |
    = help: Use `airflow.configuration.conf.set` instead
 
-AIR301_names.py:67:1: AIR301 `airflow.contrib.aws_athena_hook.AWSAthenaHook` is removed in Airflow 3.0; The whole `airflow.contrib` module has been removed.
+AIR301_names.py:64:1: AIR301 `airflow.contrib.aws_athena_hook.AWSAthenaHook` is removed in Airflow 3.0
    |
-66 | # airflow.contrib.*
-67 | AWSAthenaHook()
+63 | # airflow.contrib.*
+64 | AWSAthenaHook()
    | ^^^^^^^^^^^^^ AIR301
    |
+   = help: The whole `airflow.contrib` module has been removed.
 
-AIR301_names.py:71:1: AIR301 `airflow.datasets.DatasetAliasEvent` is removed in Airflow 3.0
+AIR301_names.py:68:1: AIR301 `airflow.datasets.DatasetAliasEvent` is removed in Airflow 3.0
    |
-70 | # airflow.datasets
-71 | DatasetAliasEvent()
+67 | # airflow.datasets
+68 | DatasetAliasEvent()
    | ^^^^^^^^^^^^^^^^^ AIR301
    |
 
-AIR301_names.py:75:1: AIR301 `airflow.hooks.base_hook.BaseHook` is removed in Airflow 3.0
+AIR301_names.py:72:1: AIR301 `airflow.hooks.base_hook.BaseHook` is removed in Airflow 3.0
    |
-74 | # airflow.hooks
-75 | BaseHook()
+71 | # airflow.hooks
+72 | BaseHook()
    | ^^^^^^^^ AIR301
    |
    = help: Use `airflow.hooks.base.BaseHook` instead
 
-AIR301_names.py:79:1: AIR301 `airflow.operators.subdag.SubDagOperator` is removed in Airflow 3.0; The whole `airflow.subdag` module has been removed.
+AIR301_names.py:76:1: AIR301 `airflow.operators.subdag.SubDagOperator` is removed in Airflow 3.0
    |
-78 | # airflow.operators.subdag.*
-79 | SubDagOperator()
+75 | # airflow.operators.subdag.*
+76 | SubDagOperator()
    | ^^^^^^^^^^^^^^ AIR301
-80 |
-81 | # airflow.providers.mysql
    |
+   = help: The whole `airflow.subdag` module has been removed.
 
-AIR301_names.py:82:7: AIR301 `airflow.providers.mysql.datasets.mysql.sanitize_uri` is removed in Airflow 3.0
+AIR301_names.py:85:1: AIR301 `airflow.sensors.base_sensor_operator.BaseSensorOperator` is removed in Airflow 3.0
    |
-81 | # airflow.providers.mysql
-82 | mysql.sanitize_uri
-   |       ^^^^^^^^^^^^ AIR301
-83 |
-84 | # airflow.providers.postgres
-   |
-   = help: Use `airflow.providers.mysql.assets.mysql.sanitize_uri` instead
-
-AIR301_names.py:85:10: AIR301 `airflow.providers.postgres.datasets.postgres.sanitize_uri` is removed in Airflow 3.0
-   |
-84 | # airflow.providers.postgres
-85 | postgres.sanitize_uri
-   |          ^^^^^^^^^^^^ AIR301
-86 |
-87 | # airflow.providers.trino
-   |
-   = help: Use `airflow.providers.postgres.assets.postgres.sanitize_uri` instead
-
-AIR301_names.py:88:7: AIR301 `airflow.providers.trino.datasets.trino.sanitize_uri` is removed in Airflow 3.0
-   |
-87 | # airflow.providers.trino
-88 | trino.sanitize_uri
-   |       ^^^^^^^^^^^^ AIR301
-89 |
-90 | # airflow.secrets
-   |
-   = help: Use `airflow.providers.trino.assets.trino.sanitize_uri` instead
-
-AIR301_names.py:96:1: AIR301 `airflow.sensors.base_sensor_operator.BaseSensorOperator` is removed in Airflow 3.0
-   |
-95 | # airflow.sensors.base_sensor_operator
-96 | BaseSensorOperator()
+84 | # airflow.sensors.base_sensor_operator
+85 | BaseSensorOperator()
    | ^^^^^^^^^^^^^^^^^^ AIR301
    |
    = help: Use `airflow.sdk.bases.sensor.BaseSensorOperator` instead
 
-AIR301_names.py:100:1: AIR301 `airflow.triggers.external_task.TaskStateTrigger` is removed in Airflow 3.0
+AIR301_names.py:89:1: AIR301 `airflow.triggers.external_task.TaskStateTrigger` is removed in Airflow 3.0
+   |
+88 | # airflow.triggers.external_task
+89 | TaskStateTrigger()
+   | ^^^^^^^^^^^^^^^^ AIR301
+90 |
+91 | # airflow.utils.date
+   |
+
+AIR301_names.py:92:7: AIR301 `airflow.utils.dates.date_range` is removed in Airflow 3.0
+   |
+91 | # airflow.utils.date
+92 | dates.date_range
+   |       ^^^^^^^^^^ AIR301
+93 | dates.days_ago
+   |
+
+AIR301_names.py:93:7: AIR301 `airflow.utils.dates.days_ago` is removed in Airflow 3.0
+   |
+91 | # airflow.utils.date
+92 | dates.date_range
+93 | dates.days_ago
+   |       ^^^^^^^^ AIR301
+94 |
+95 | date_range
+   |
+   = help: Use `pendulum.today('UTC').add(days=-N, ...)` instead
+
+AIR301_names.py:95:1: AIR301 `airflow.utils.dates.date_range` is removed in Airflow 3.0
+   |
+93 | dates.days_ago
+94 |
+95 | date_range
+   | ^^^^^^^^^^ AIR301
+96 | days_ago
+97 | infer_time_unit
+   |
+
+AIR301_names.py:96:1: AIR301 `airflow.utils.dates.days_ago` is removed in Airflow 3.0
+   |
+95 | date_range
+96 | days_ago
+   | ^^^^^^^^ AIR301
+97 | infer_time_unit
+98 | parse_execution_date
+   |
+   = help: Use `pendulum.today('UTC').add(days=-N, ...)` instead
+
+AIR301_names.py:97:1: AIR301 `airflow.utils.dates.infer_time_unit` is removed in Airflow 3.0
+   |
+95 | date_range
+96 | days_ago
+97 | infer_time_unit
+   | ^^^^^^^^^^^^^^^ AIR301
+98 | parse_execution_date
+99 | round_time
+   |
+
+AIR301_names.py:98:1: AIR301 `airflow.utils.dates.parse_execution_date` is removed in Airflow 3.0
     |
- 99 | # airflow.triggers.external_task
-100 | TaskStateTrigger()
+ 96 | days_ago
+ 97 | infer_time_unit
+ 98 | parse_execution_date
+    | ^^^^^^^^^^^^^^^^^^^^ AIR301
+ 99 | round_time
+100 | scale_time_units
+    |
+
+AIR301_names.py:99:1: AIR301 `airflow.utils.dates.round_time` is removed in Airflow 3.0
+    |
+ 97 | infer_time_unit
+ 98 | parse_execution_date
+ 99 | round_time
+    | ^^^^^^^^^^ AIR301
+100 | scale_time_units
+    |
+
+AIR301_names.py:100:1: AIR301 `airflow.utils.dates.scale_time_units` is removed in Airflow 3.0
+    |
+ 98 | parse_execution_date
+ 99 | round_time
+100 | scale_time_units
     | ^^^^^^^^^^^^^^^^ AIR301
 101 |
-102 | # airflow.utils.date
+102 | # This one was not deprecated.
     |
 
-AIR301_names.py:103:7: AIR301 `airflow.utils.dates.date_range` is removed in Airflow 3.0
+AIR301_names.py:107:1: AIR301 `airflow.utils.dag_cycle_tester.test_cycle` is removed in Airflow 3.0
     |
-102 | # airflow.utils.date
-103 | dates.date_range
-    |       ^^^^^^^^^^ AIR301
-104 | dates.days_ago
-    |
-
-AIR301_names.py:104:7: AIR301 `airflow.utils.dates.days_ago` is removed in Airflow 3.0
-    |
-102 | # airflow.utils.date
-103 | dates.date_range
-104 | dates.days_ago
-    |       ^^^^^^^^ AIR301
-105 |
-106 | date_range
-    |
-    = help: Use `pendulum.today('UTC').add(days=-N, ...)` instead
-
-AIR301_names.py:106:1: AIR301 `airflow.utils.dates.date_range` is removed in Airflow 3.0
-    |
-104 | dates.days_ago
-105 |
-106 | date_range
+106 | # airflow.utils.dag_cycle_tester
+107 | test_cycle
     | ^^^^^^^^^^ AIR301
-107 | days_ago
-108 | infer_time_unit
     |
 
-AIR301_names.py:107:1: AIR301 `airflow.utils.dates.days_ago` is removed in Airflow 3.0
+AIR301_names.py:111:1: AIR301 `airflow.utils.db.create_session` is removed in Airflow 3.0
     |
-106 | date_range
-107 | days_ago
-    | ^^^^^^^^ AIR301
-108 | infer_time_unit
-109 | parse_execution_date
-    |
-    = help: Use `pendulum.today('UTC').add(days=-N, ...)` instead
-
-AIR301_names.py:108:1: AIR301 `airflow.utils.dates.infer_time_unit` is removed in Airflow 3.0
-    |
-106 | date_range
-107 | days_ago
-108 | infer_time_unit
-    | ^^^^^^^^^^^^^^^ AIR301
-109 | parse_execution_date
-110 | round_time
-    |
-
-AIR301_names.py:109:1: AIR301 `airflow.utils.dates.parse_execution_date` is removed in Airflow 3.0
-    |
-107 | days_ago
-108 | infer_time_unit
-109 | parse_execution_date
-    | ^^^^^^^^^^^^^^^^^^^^ AIR301
-110 | round_time
-111 | scale_time_units
-    |
-
-AIR301_names.py:110:1: AIR301 `airflow.utils.dates.round_time` is removed in Airflow 3.0
-    |
-108 | infer_time_unit
-109 | parse_execution_date
-110 | round_time
-    | ^^^^^^^^^^ AIR301
-111 | scale_time_units
-    |
-
-AIR301_names.py:111:1: AIR301 `airflow.utils.dates.scale_time_units` is removed in Airflow 3.0
-    |
-109 | parse_execution_date
-110 | round_time
-111 | scale_time_units
-    | ^^^^^^^^^^^^^^^^ AIR301
+110 | # airflow.utils.db
+111 | create_session
+    | ^^^^^^^^^^^^^^ AIR301
 112 |
-113 | # This one was not deprecated.
+113 | # airflow.utils.decorators
     |
 
-AIR301_names.py:118:1: AIR301 `airflow.utils.dag_cycle_tester.test_cycle` is removed in Airflow 3.0
+AIR301_names.py:114:1: AIR301 `airflow.utils.decorators.apply_defaults` is removed in Airflow 3.0
     |
-117 | # airflow.utils.dag_cycle_tester
-118 | test_cycle
-    | ^^^^^^^^^^ AIR301
-    |
-
-AIR301_names.py:122:1: AIR301 `airflow.utils.db.create_session` is removed in Airflow 3.0
-    |
-121 | # airflow.utils.db
-122 | create_session
+113 | # airflow.utils.decorators
+114 | apply_defaults
     | ^^^^^^^^^^^^^^ AIR301
-123 |
-124 | # airflow.utils.decorators
+115 |
+116 | # airflow.utils.file
     |
+    = help: `apply_defaults` is now unconditionally done and can be safely removed.
 
-AIR301_names.py:125:1: AIR301 `airflow.utils.decorators.apply_defaults` is removed in Airflow 3.0; `apply_defaults` is now unconditionally done and can be safely removed.
+AIR301_names.py:117:1: AIR301 `airflow.utils.file.TemporaryDirectory` is removed in Airflow 3.0
     |
-124 | # airflow.utils.decorators
-125 | apply_defaults
-    | ^^^^^^^^^^^^^^ AIR301
-126 |
-127 | # airflow.utils.file
-    |
-
-AIR301_names.py:128:1: AIR301 `airflow.utils.file.TemporaryDirectory` is removed in Airflow 3.0
-    |
-127 | # airflow.utils.file
-128 | TemporaryDirectory()
+116 | # airflow.utils.file
+117 | TemporaryDirectory()
     | ^^^^^^^^^^^^^^^^^^ AIR301
-129 | mkdirs
+118 | mkdirs
     |
     = help: Use `tempfile.TemporaryDirectory` instead
 
-AIR301_names.py:129:1: AIR301 `airflow.utils.file.mkdirs` is removed in Airflow 3.0
+AIR301_names.py:118:1: AIR301 `airflow.utils.file.mkdirs` is removed in Airflow 3.0
     |
-127 | # airflow.utils.file
-128 | TemporaryDirectory()
-129 | mkdirs
+116 | # airflow.utils.file
+117 | TemporaryDirectory()
+118 | mkdirs
     | ^^^^^^ AIR301
-130 |
-131 | #  airflow.utils.helpers
+119 |
+120 | #  airflow.utils.helpers
     |
     = help: Use `pathlib.Path({path}).mkdir` instead
 
-AIR301_names.py:132:1: AIR301 `airflow.utils.helpers.chain` is removed in Airflow 3.0
+AIR301_names.py:121:1: AIR301 [*] `airflow.utils.helpers.chain` is removed in Airflow 3.0
     |
-131 | #  airflow.utils.helpers
-132 | helper_chain
+120 | #  airflow.utils.helpers
+121 | helper_chain
     | ^^^^^^^^^^^^ AIR301
-133 | helper_cross_downstream
+122 | helper_cross_downstream
     |
     = help: Use `airflow.sdk.chain` instead
 
-AIR301_names.py:133:1: AIR301 `airflow.utils.helpers.cross_downstream` is removed in Airflow 3.0
+ℹ Safe fix
+48  48  | from airflow.utils.trigger_rule import TriggerRule
+49  49  | from airflow.www.auth import has_access
+50  50  | from airflow.www.utils import get_sensitive_variables_fields, should_hide_value_for_key
+    51  |+from airflow.sdk import chain
+51  52  | 
+52  53  | # airflow root
+53  54  | PY36, PY37, PY38, PY39, PY310, PY311, PY312
+--------------------------------------------------------------------------------
+118 119 | mkdirs
+119 120 | 
+120 121 | #  airflow.utils.helpers
+121     |-helper_chain
+    122 |+chain
+122 123 | helper_cross_downstream
+123 124 | 
+124 125 | #  airflow.utils.log
+
+AIR301_names.py:122:1: AIR301 [*] `airflow.utils.helpers.cross_downstream` is removed in Airflow 3.0
     |
-131 | #  airflow.utils.helpers
-132 | helper_chain
-133 | helper_cross_downstream
+120 | #  airflow.utils.helpers
+121 | helper_chain
+122 | helper_cross_downstream
     | ^^^^^^^^^^^^^^^^^^^^^^^ AIR301
-134 |
-135 | #  airflow.utils.log
+123 |
+124 | #  airflow.utils.log
     |
     = help: Use `airflow.sdk.cross_downstream` instead
 
-AIR301_names.py:136:1: AIR301 `airflow.utils.log.secrets_masker` is removed in Airflow 3.0
+ℹ Safe fix
+48  48  | from airflow.utils.trigger_rule import TriggerRule
+49  49  | from airflow.www.auth import has_access
+50  50  | from airflow.www.utils import get_sensitive_variables_fields, should_hide_value_for_key
+    51  |+from airflow.sdk import cross_downstream
+51  52  | 
+52  53  | # airflow root
+53  54  | PY36, PY37, PY38, PY39, PY310, PY311, PY312
+--------------------------------------------------------------------------------
+119 120 | 
+120 121 | #  airflow.utils.helpers
+121 122 | helper_chain
+122     |-helper_cross_downstream
+    123 |+cross_downstream
+123 124 | 
+124 125 | #  airflow.utils.log
+125 126 | secrets_masker
+
+AIR301_names.py:125:1: AIR301 `airflow.utils.log.secrets_masker` is removed in Airflow 3.0
     |
-135 | #  airflow.utils.log
-136 | secrets_masker
+124 | #  airflow.utils.log
+125 | secrets_masker
     | ^^^^^^^^^^^^^^ AIR301
-137 |
-138 | # airflow.utils.state
+126 |
+127 | # airflow.utils.state
     |
     = help: Use `airflow.sdk.execution_time.secrets_masker` instead
 
-AIR301_names.py:139:1: AIR301 `airflow.utils.state.SHUTDOWN` is removed in Airflow 3.0
+AIR301_names.py:128:1: AIR301 `airflow.utils.state.SHUTDOWN` is removed in Airflow 3.0
     |
-138 | # airflow.utils.state
-139 | SHUTDOWN
+127 | # airflow.utils.state
+128 | SHUTDOWN
     | ^^^^^^^^ AIR301
-140 | terminating_states
+129 | terminating_states
     |
 
-AIR301_names.py:140:1: AIR301 `airflow.utils.state.terminating_states` is removed in Airflow 3.0
+AIR301_names.py:129:1: AIR301 `airflow.utils.state.terminating_states` is removed in Airflow 3.0
     |
-138 | # airflow.utils.state
-139 | SHUTDOWN
-140 | terminating_states
+127 | # airflow.utils.state
+128 | SHUTDOWN
+129 | terminating_states
     | ^^^^^^^^^^^^^^^^^^ AIR301
-141 |
-142 | #  airflow.utils.trigger_rule
+130 |
+131 | #  airflow.utils.trigger_rule
     |
 
-AIR301_names.py:143:13: AIR301 `airflow.utils.trigger_rule.TriggerRule.DUMMY` is removed in Airflow 3.0
+AIR301_names.py:132:13: AIR301 `airflow.utils.trigger_rule.TriggerRule.DUMMY` is removed in Airflow 3.0
     |
-142 | #  airflow.utils.trigger_rule
-143 | TriggerRule.DUMMY
+131 | #  airflow.utils.trigger_rule
+132 | TriggerRule.DUMMY
     |             ^^^^^ AIR301
-144 | TriggerRule.NONE_FAILED_OR_SKIPPED
+133 | TriggerRule.NONE_FAILED_OR_SKIPPED
     |
 
-AIR301_names.py:144:13: AIR301 `airflow.utils.trigger_rule.TriggerRule.NONE_FAILED_OR_SKIPPED` is removed in Airflow 3.0
+AIR301_names.py:133:13: AIR301 `airflow.utils.trigger_rule.TriggerRule.NONE_FAILED_OR_SKIPPED` is removed in Airflow 3.0
     |
-142 | #  airflow.utils.trigger_rule
-143 | TriggerRule.DUMMY
-144 | TriggerRule.NONE_FAILED_OR_SKIPPED
+131 | #  airflow.utils.trigger_rule
+132 | TriggerRule.DUMMY
+133 | TriggerRule.NONE_FAILED_OR_SKIPPED
     |             ^^^^^^^^^^^^^^^^^^^^^^ AIR301
     |
 
-AIR301_names.py:148:1: AIR301 `airflow.www.auth.has_access` is removed in Airflow 3.0
+AIR301_names.py:137:1: AIR301 `airflow.www.auth.has_access` is removed in Airflow 3.0
     |
-147 | # airflow.www.auth
-148 | has_access
+136 | # airflow.www.auth
+137 | has_access
     | ^^^^^^^^^^ AIR301
-149 |
-150 | # airflow.www.utils
+138 |
+139 | # airflow.www.utils
     |
     = help: Use `airflow.www.auth.has_access_*` instead
 
-AIR301_names.py:151:1: AIR301 `airflow.www.utils.get_sensitive_variables_fields` is removed in Airflow 3.0
+AIR301_names.py:140:1: AIR301 `airflow.www.utils.get_sensitive_variables_fields` is removed in Airflow 3.0
     |
-150 | # airflow.www.utils
-151 | get_sensitive_variables_fields
+139 | # airflow.www.utils
+140 | get_sensitive_variables_fields
     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ AIR301
-152 | should_hide_value_for_key
+141 | should_hide_value_for_key
     |
     = help: Use `airflow.utils.log.secrets_masker.get_sensitive_variables_fields` instead
 
-AIR301_names.py:152:1: AIR301 `airflow.www.utils.should_hide_value_for_key` is removed in Airflow 3.0
+AIR301_names.py:141:1: AIR301 `airflow.www.utils.should_hide_value_for_key` is removed in Airflow 3.0
     |
-150 | # airflow.www.utils
-151 | get_sensitive_variables_fields
-152 | should_hide_value_for_key
+139 | # airflow.www.utils
+140 | get_sensitive_variables_fields
+141 | should_hide_value_for_key
     | ^^^^^^^^^^^^^^^^^^^^^^^^^ AIR301
-153 |
-154 | # airflow.operators.python
+142 |
+143 | # airflow.operators.python
     |
     = help: Use `airflow.utils.log.secrets_masker.should_hide_value_for_key` instead
 
-AIR301_names.py:157:1: AIR301 `airflow.operators.python.get_current_context` is removed in Airflow 3.0
+AIR301_names.py:146:1: AIR301 `airflow.operators.python.get_current_context` is removed in Airflow 3.0
     |
-155 | from airflow.operators.python import get_current_context
-156 |
-157 | get_current_context()
+144 | from airflow.operators.python import get_current_context
+145 |
+146 | get_current_context()
     | ^^^^^^^^^^^^^^^^^^^ AIR301
+147 |
+148 | # airflow.providers.mysql
     |
     = help: Use `airflow.sdk.get_current_context` instead
+
+AIR301_names.py:151:1: AIR301 `airflow.providers.mysql.datasets.mysql.sanitize_uri` is removed in Airflow 3.0
+    |
+149 | from airflow.providers.mysql.datasets.mysql import sanitize_uri
+150 |
+151 | sanitize_uri
+    | ^^^^^^^^^^^^ AIR301
+152 |
+153 | # airflow.providers.postgres
+    |
+    = help: Use `airflow.providers.mysql.assets.mysql.sanitize_uri` instead
+
+AIR301_names.py:156:1: AIR301 `airflow.providers.postgres.datasets.postgres.sanitize_uri` is removed in Airflow 3.0
+    |
+154 | from airflow.providers.postgres.datasets.postgres import sanitize_uri
+155 |
+156 | sanitize_uri
+    | ^^^^^^^^^^^^ AIR301
+157 |
+158 | # airflow.providers.trino
+    |
+    = help: Use `airflow.providers.postgres.assets.postgres.sanitize_uri` instead
+
+AIR301_names.py:161:1: AIR301 `airflow.providers.trino.datasets.trino.sanitize_uri` is removed in Airflow 3.0
+    |
+159 | from airflow.providers.trino.datasets.trino import sanitize_uri
+160 |
+161 | sanitize_uri
+    | ^^^^^^^^^^^^ AIR301
+    |
+    = help: Use `airflow.providers.trino.assets.trino.sanitize_uri` instead

crates/ruff_linter/src/rules/flake8_pytest_style/rules/fixture.rs

@@ -1,6 +1,7 @@
 use ruff_diagnostics::{AlwaysFixableViolation, Violation};
 use ruff_diagnostics::{Diagnostic, Edit, Fix};
 use ruff_macros::{derive_message_formats, ViolationMetadata};
+use ruff_python_ast::helpers::map_callable;
 use ruff_python_ast::name::UnqualifiedName;
 use ruff_python_ast::visitor;
 use ruff_python_ast::visitor::Visitor;
@@ -11,6 +12,7 @@ use ruff_python_semantic::SemanticModel;
 use ruff_source_file::LineRanges;
 use ruff_text_size::Ranged;
 use ruff_text_size::{TextLen, TextRange};
+use rustc_hash::FxHashSet;
 
 use crate::checkers::ast::Checker;
 use crate::fix::edits;
@@ -807,10 +809,51 @@ fn check_fixture_returns(checker: &Checker, name: &str, body: &[Stmt], returns:
 }
 
 /// PT019
-fn check_test_function_args(checker: &Checker, parameters: &Parameters) {
+fn check_test_function_args(checker: &Checker, parameters: &Parameters, decorators: &[Decorator]) {
+    let mut named_parametrize = FxHashSet::default();
+    for decorator in decorators.iter().filter(|decorator| {
+        UnqualifiedName::from_expr(map_callable(&decorator.expression))
+            .is_some_and(|name| matches!(name.segments(), ["pytest", "mark", "parametrize"]))
+    }) {
+        let Some(call_expr) = decorator.expression.as_call_expr() else {
+            continue;
+        };
+        let Some(first_arg) = call_expr.arguments.find_argument_value("argnames", 0) else {
+            continue;
+        };
+
+        match first_arg {
+            Expr::StringLiteral(ast::ExprStringLiteral { value, .. }) => {
+                named_parametrize.extend(
+                    value
+                        .to_str()
+                        .split(',')
+                        .map(str::trim)
+                        .filter(|param| !param.is_empty() && param.starts_with('_')),
+                );
+            }
+
+            Expr::Name(_) => return,
+            Expr::List(ast::ExprList { elts, .. }) | Expr::Tuple(ast::ExprTuple { elts, .. })
+                if elts.iter().any(Expr::is_name_expr) =>
+            {
+                return
+            }
+            Expr::List(ast::ExprList { elts, .. }) | Expr::Tuple(ast::ExprTuple { elts, .. }) => {
+                named_parametrize.extend(
+                    elts.iter()
+                        .filter_map(Expr::as_string_literal_expr)
+                        .map(|param| param.value.to_str().trim())
+                        .filter(|param| !param.is_empty() && param.starts_with('_')),
+                );
+            }
+            _ => {}
+        }
+    }
+
     for parameter in parameters.iter_non_variadic_params() {
         let name = parameter.name();
-        if name.starts_with('_') {
+        if name.starts_with('_') && !named_parametrize.contains(name.as_str()) {
             checker.report_diagnostic(Diagnostic::new(
                 PytestFixtureParamWithoutValue {
                     name: name.to_string(),
@@ -915,6 +958,6 @@ pub(crate) fn fixture(
     }
 
     if checker.enabled(Rule::PytestFixtureParamWithoutValue) && name.starts_with("test_") {
-        check_test_function_args(checker, parameters);
+        check_test_function_args(checker, parameters, decorators);
     }
 }

crates/ruff_linter/src/rules/flake8_pytest_style/snapshots/ruff_linter__rules__flake8_pytest_style__tests__PT019.snap

@@ -1,6 +1,5 @@
 ---
 source: crates/ruff_linter/src/rules/flake8_pytest_style/mod.rs
-snapshot_kind: text
 ---
 PT019.py:9:14: PT019 Fixture `_fixture` without value is injected as parameter, use `@pytest.mark.usefixtures` instead
    |
@@ -15,3 +14,19 @@ PT019.py:13:17: PT019 Fixture `_fixture` without value is injected as parameter,
    |                 ^^^^^^^^ PT019
 14 |     pass
    |
+
+PT019.py:31:24: PT019 Fixture `_bar` without value is injected as parameter, use `@pytest.mark.usefixtures` instead
+   |
+30 | @pytest.mark.parametrize("_foo", [1, 2, 3])
+31 | def test_thingy2(_foo, _bar):  # Error _bar is not defined in parametrize
+   |                        ^^^^ PT019
+32 |     pass
+   |
+
+PT019.py:39:24: PT019 Fixture `_bar` without value is injected as parameter, use `@pytest.mark.usefixtures` instead
+   |
+38 | @pytest.mark.parametrize(("_foo"), [1, 2, 3])
+39 | def test_thingy4(_foo, _bar):  # Error _bar is not defined in parametrize
+   |                        ^^^^ PT019
+40 |     pass
+   |

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

@@ -83,7 +83,7 @@ pub(crate) fn split_static_string(
     let sep_arg = arguments.find_argument_value("sep", 0);
     let split_replacement = if let Some(sep) = sep_arg {
         match sep {
-            Expr::NoneLiteral(_) => split_default(str_value, maxsplit_value),
+            Expr::NoneLiteral(_) => split_default(str_value, maxsplit_value, direction),
             Expr::StringLiteral(sep_value) => {
                 let sep_value_str = sep_value.value.to_str();
                 Some(split_sep(
@@ -99,7 +99,7 @@ pub(crate) fn split_static_string(
             }
         }
     } else {
-        split_default(str_value, maxsplit_value)
+        split_default(str_value, maxsplit_value, direction)
     };
 
     let mut diagnostic = Diagnostic::new(SplitStaticString, call.range());
@@ -144,7 +144,11 @@ fn construct_replacement(elts: &[&str], flags: StringLiteralFlags) -> Expr {
     })
 }
 
-fn split_default(str_value: &StringLiteralValue, max_split: i32) -> Option<Expr> {
+fn split_default(
+    str_value: &StringLiteralValue,
+    max_split: i32,
+    direction: Direction,
+) -> Option<Expr> {
     // From the Python documentation:
     // > If sep is not specified or is None, a different splitting algorithm is applied: runs of
     // > consecutive whitespace are regarded as a single separator, and the result will contain
@@ -152,6 +156,7 @@ fn split_default(str_value: &StringLiteralValue, max_split: i32) -> Option<Expr>
     // > Consequently, splitting an empty string or a string consisting of just whitespace with
     // > a None separator returns [].
     // https://docs.python.org/3/library/stdtypes.html#str.split
+    let string_val = str_value.to_str();
     match max_split.cmp(&0) {
         Ordering::Greater => {
             // Autofix for `maxsplit` without separator not yet implemented, as
@@ -160,14 +165,30 @@ fn split_default(str_value: &StringLiteralValue, max_split: i32) -> Option<Expr>
             None
         }
         Ordering::Equal => {
-            let list_items: Vec<&str> = vec![str_value.to_str()];
+            // Behavior for maxsplit = 0 when sep is None:
+            // - If the string is empty or all whitespace, result is [].
+            // - Otherwise:
+            //   - " x ".split(maxsplit=0)  -> ['x ']
+            //   - " x ".rsplit(maxsplit=0) -> [' x']
+            //   - "".split(maxsplit=0) -> []
+            //   - " ".split(maxsplit=0) -> []
+            let processed_str = if direction == Direction::Left {
+                string_val.trim_start()
+            } else {
+                string_val.trim_end()
+            };
+            let list_items: &[_] = if processed_str.is_empty() {
+                &[]
+            } else {
+                &[processed_str]
+            };
             Some(construct_replacement(
-                &list_items,
+                list_items,
                 str_value.first_literal_flags(),
             ))
         }
         Ordering::Less => {
-            let list_items: Vec<&str> = str_value.to_str().split_whitespace().collect();
+            let list_items: Vec<&str> = string_val.split_whitespace().collect();
             Some(construct_replacement(
                 &list_items,
                 str_value.first_literal_flags(),

crates/ruff_linter/src/rules/flake8_simplify/snapshots/ruff_linter__rules__flake8_simplify__tests__SIM905_SIM905.py.snap

@@ -890,6 +890,8 @@ SIM905.py:111:7: SIM905 [*] Consider using a list literal instead of `str.split`
 111     |-print("a,b".rsplit(","))
     111 |+print(["a", "b"])
 112 112 | print("a,b,c".rsplit(",", 1))
+113 113 | 
+114 114 | # https://github.com/astral-sh/ruff/issues/18069
 
 SIM905.py:112:7: SIM905 [*] Consider using a list literal instead of `str.split`
     |
@@ -897,6 +899,8 @@ SIM905.py:112:7: SIM905 [*] Consider using a list literal instead of `str.split`
 111 | print("a,b".rsplit(","))
 112 | print("a,b,c".rsplit(",", 1))
     |       ^^^^^^^^^^^^^^^^^^^^^^ SIM905
+113 |
+114 | # https://github.com/astral-sh/ruff/issues/18069
     |
     = help: Replace with list literal
 
@@ -906,3 +910,353 @@ SIM905.py:112:7: SIM905 [*] Consider using a list literal instead of `str.split`
 111 111 | print("a,b".rsplit(","))
 112     |-print("a,b,c".rsplit(",", 1))
     112 |+print(["a,b", "c"])
+113 113 | 
+114 114 | # https://github.com/astral-sh/ruff/issues/18069
+115 115 | 
+
+SIM905.py:116:7: SIM905 [*] Consider using a list literal instead of `str.split`
+    |
+114 | # https://github.com/astral-sh/ruff/issues/18069
+115 |
+116 | print("".split(maxsplit=0))
+    |       ^^^^^^^^^^^^^^^^^^^^ SIM905
+117 | print("".split(sep=None, maxsplit=0))
+118 | print(" ".split(maxsplit=0))
+    |
+    = help: Replace with list literal
+
+ℹ Safe fix
+113 113 | 
+114 114 | # https://github.com/astral-sh/ruff/issues/18069
+115 115 | 
+116     |-print("".split(maxsplit=0))
+    116 |+print([])
+117 117 | print("".split(sep=None, maxsplit=0))
+118 118 | print(" ".split(maxsplit=0))
+119 119 | print(" ".split(sep=None, maxsplit=0))
+
+SIM905.py:117:7: SIM905 [*] Consider using a list literal instead of `str.split`
+    |
+116 | print("".split(maxsplit=0))
+117 | print("".split(sep=None, maxsplit=0))
+    |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ SIM905
+118 | print(" ".split(maxsplit=0))
+119 | print(" ".split(sep=None, maxsplit=0))
+    |
+    = help: Replace with list literal
+
+ℹ Safe fix
+114 114 | # https://github.com/astral-sh/ruff/issues/18069
+115 115 | 
+116 116 | print("".split(maxsplit=0))
+117     |-print("".split(sep=None, maxsplit=0))
+    117 |+print([])
+118 118 | print(" ".split(maxsplit=0))
+119 119 | print(" ".split(sep=None, maxsplit=0))
+120 120 | print(" x ".split(maxsplit=0))
+
+SIM905.py:118:7: SIM905 [*] Consider using a list literal instead of `str.split`
+    |
+116 | print("".split(maxsplit=0))
+117 | print("".split(sep=None, maxsplit=0))
+118 | print(" ".split(maxsplit=0))
+    |       ^^^^^^^^^^^^^^^^^^^^^ SIM905
+119 | print(" ".split(sep=None, maxsplit=0))
+120 | print(" x ".split(maxsplit=0))
+    |
+    = help: Replace with list literal
+
+ℹ Safe fix
+115 115 | 
+116 116 | print("".split(maxsplit=0))
+117 117 | print("".split(sep=None, maxsplit=0))
+118     |-print(" ".split(maxsplit=0))
+    118 |+print([])
+119 119 | print(" ".split(sep=None, maxsplit=0))
+120 120 | print(" x ".split(maxsplit=0))
+121 121 | print(" x ".split(sep=None, maxsplit=0))
+
+SIM905.py:119:7: SIM905 [*] Consider using a list literal instead of `str.split`
+    |
+117 | print("".split(sep=None, maxsplit=0))
+118 | print(" ".split(maxsplit=0))
+119 | print(" ".split(sep=None, maxsplit=0))
+    |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ SIM905
+120 | print(" x ".split(maxsplit=0))
+121 | print(" x ".split(sep=None, maxsplit=0))
+    |
+    = help: Replace with list literal
+
+ℹ Safe fix
+116 116 | print("".split(maxsplit=0))
+117 117 | print("".split(sep=None, maxsplit=0))
+118 118 | print(" ".split(maxsplit=0))
+119     |-print(" ".split(sep=None, maxsplit=0))
+    119 |+print([])
+120 120 | print(" x ".split(maxsplit=0))
+121 121 | print(" x ".split(sep=None, maxsplit=0))
+122 122 | print("  x  ".split(maxsplit=0))
+
+SIM905.py:120:7: SIM905 [*] Consider using a list literal instead of `str.split`
+    |
+118 | print(" ".split(maxsplit=0))
+119 | print(" ".split(sep=None, maxsplit=0))
+120 | print(" x ".split(maxsplit=0))
+    |       ^^^^^^^^^^^^^^^^^^^^^^^ SIM905
+121 | print(" x ".split(sep=None, maxsplit=0))
+122 | print("  x  ".split(maxsplit=0))
+    |
+    = help: Replace with list literal
+
+ℹ Safe fix
+117 117 | print("".split(sep=None, maxsplit=0))
+118 118 | print(" ".split(maxsplit=0))
+119 119 | print(" ".split(sep=None, maxsplit=0))
+120     |-print(" x ".split(maxsplit=0))
+    120 |+print(["x "])
+121 121 | print(" x ".split(sep=None, maxsplit=0))
+122 122 | print("  x  ".split(maxsplit=0))
+123 123 | print("  x  ".split(sep=None, maxsplit=0))
+
+SIM905.py:121:7: SIM905 [*] Consider using a list literal instead of `str.split`
+    |
+119 | print(" ".split(sep=None, maxsplit=0))
+120 | print(" x ".split(maxsplit=0))
+121 | print(" x ".split(sep=None, maxsplit=0))
+    |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ SIM905
+122 | print("  x  ".split(maxsplit=0))
+123 | print("  x  ".split(sep=None, maxsplit=0))
+    |
+    = help: Replace with list literal
+
+ℹ Safe fix
+118 118 | print(" ".split(maxsplit=0))
+119 119 | print(" ".split(sep=None, maxsplit=0))
+120 120 | print(" x ".split(maxsplit=0))
+121     |-print(" x ".split(sep=None, maxsplit=0))
+    121 |+print(["x "])
+122 122 | print("  x  ".split(maxsplit=0))
+123 123 | print("  x  ".split(sep=None, maxsplit=0))
+124 124 | print("".rsplit(maxsplit=0))
+
+SIM905.py:122:7: SIM905 [*] Consider using a list literal instead of `str.split`
+    |
+120 | print(" x ".split(maxsplit=0))
+121 | print(" x ".split(sep=None, maxsplit=0))
+122 | print("  x  ".split(maxsplit=0))
+    |       ^^^^^^^^^^^^^^^^^^^^^^^^^ SIM905
+123 | print("  x  ".split(sep=None, maxsplit=0))
+124 | print("".rsplit(maxsplit=0))
+    |
+    = help: Replace with list literal
+
+ℹ Safe fix
+119 119 | print(" ".split(sep=None, maxsplit=0))
+120 120 | print(" x ".split(maxsplit=0))
+121 121 | print(" x ".split(sep=None, maxsplit=0))
+122     |-print("  x  ".split(maxsplit=0))
+    122 |+print(["x  "])
+123 123 | print("  x  ".split(sep=None, maxsplit=0))
+124 124 | print("".rsplit(maxsplit=0))
+125 125 | print("".rsplit(sep=None, maxsplit=0))
+
+SIM905.py:123:7: SIM905 [*] Consider using a list literal instead of `str.split`
+    |
+121 | print(" x ".split(sep=None, maxsplit=0))
+122 | print("  x  ".split(maxsplit=0))
+123 | print("  x  ".split(sep=None, maxsplit=0))
+    |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ SIM905
+124 | print("".rsplit(maxsplit=0))
+125 | print("".rsplit(sep=None, maxsplit=0))
+    |
+    = help: Replace with list literal
+
+ℹ Safe fix
+120 120 | print(" x ".split(maxsplit=0))
+121 121 | print(" x ".split(sep=None, maxsplit=0))
+122 122 | print("  x  ".split(maxsplit=0))
+123     |-print("  x  ".split(sep=None, maxsplit=0))
+    123 |+print(["x  "])
+124 124 | print("".rsplit(maxsplit=0))
+125 125 | print("".rsplit(sep=None, maxsplit=0))
+126 126 | print(" ".rsplit(maxsplit=0))
+
+SIM905.py:124:7: SIM905 [*] Consider using a list literal instead of `str.split`
+    |
+122 | print("  x  ".split(maxsplit=0))
+123 | print("  x  ".split(sep=None, maxsplit=0))
+124 | print("".rsplit(maxsplit=0))
+    |       ^^^^^^^^^^^^^^^^^^^^^ SIM905
+125 | print("".rsplit(sep=None, maxsplit=0))
+126 | print(" ".rsplit(maxsplit=0))
+    |
+    = help: Replace with list literal
+
+ℹ Safe fix
+121 121 | print(" x ".split(sep=None, maxsplit=0))
+122 122 | print("  x  ".split(maxsplit=0))
+123 123 | print("  x  ".split(sep=None, maxsplit=0))
+124     |-print("".rsplit(maxsplit=0))
+    124 |+print([])
+125 125 | print("".rsplit(sep=None, maxsplit=0))
+126 126 | print(" ".rsplit(maxsplit=0))
+127 127 | print(" ".rsplit(sep=None, maxsplit=0))
+
+SIM905.py:125:7: SIM905 [*] Consider using a list literal instead of `str.split`
+    |
+123 | print("  x  ".split(sep=None, maxsplit=0))
+124 | print("".rsplit(maxsplit=0))
+125 | print("".rsplit(sep=None, maxsplit=0))
+    |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ SIM905
+126 | print(" ".rsplit(maxsplit=0))
+127 | print(" ".rsplit(sep=None, maxsplit=0))
+    |
+    = help: Replace with list literal
+
+ℹ Safe fix
+122 122 | print("  x  ".split(maxsplit=0))
+123 123 | print("  x  ".split(sep=None, maxsplit=0))
+124 124 | print("".rsplit(maxsplit=0))
+125     |-print("".rsplit(sep=None, maxsplit=0))
+    125 |+print([])
+126 126 | print(" ".rsplit(maxsplit=0))
+127 127 | print(" ".rsplit(sep=None, maxsplit=0))
+128 128 | print(" x ".rsplit(maxsplit=0))
+
+SIM905.py:126:7: SIM905 [*] Consider using a list literal instead of `str.split`
+    |
+124 | print("".rsplit(maxsplit=0))
+125 | print("".rsplit(sep=None, maxsplit=0))
+126 | print(" ".rsplit(maxsplit=0))
+    |       ^^^^^^^^^^^^^^^^^^^^^^ SIM905
+127 | print(" ".rsplit(sep=None, maxsplit=0))
+128 | print(" x ".rsplit(maxsplit=0))
+    |
+    = help: Replace with list literal
+
+ℹ Safe fix
+123 123 | print("  x  ".split(sep=None, maxsplit=0))
+124 124 | print("".rsplit(maxsplit=0))
+125 125 | print("".rsplit(sep=None, maxsplit=0))
+126     |-print(" ".rsplit(maxsplit=0))
+    126 |+print([])
+127 127 | print(" ".rsplit(sep=None, maxsplit=0))
+128 128 | print(" x ".rsplit(maxsplit=0))
+129 129 | print(" x ".rsplit(maxsplit=0))
+
+SIM905.py:127:7: SIM905 [*] Consider using a list literal instead of `str.split`
+    |
+125 | print("".rsplit(sep=None, maxsplit=0))
+126 | print(" ".rsplit(maxsplit=0))
+127 | print(" ".rsplit(sep=None, maxsplit=0))
+    |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ SIM905
+128 | print(" x ".rsplit(maxsplit=0))
+129 | print(" x ".rsplit(maxsplit=0))
+    |
+    = help: Replace with list literal
+
+ℹ Safe fix
+124 124 | print("".rsplit(maxsplit=0))
+125 125 | print("".rsplit(sep=None, maxsplit=0))
+126 126 | print(" ".rsplit(maxsplit=0))
+127     |-print(" ".rsplit(sep=None, maxsplit=0))
+    127 |+print([])
+128 128 | print(" x ".rsplit(maxsplit=0))
+129 129 | print(" x ".rsplit(maxsplit=0))
+130 130 | print(" x ".rsplit(sep=None, maxsplit=0))
+
+SIM905.py:128:7: SIM905 [*] Consider using a list literal instead of `str.split`
+    |
+126 | print(" ".rsplit(maxsplit=0))
+127 | print(" ".rsplit(sep=None, maxsplit=0))
+128 | print(" x ".rsplit(maxsplit=0))
+    |       ^^^^^^^^^^^^^^^^^^^^^^^^ SIM905
+129 | print(" x ".rsplit(maxsplit=0))
+130 | print(" x ".rsplit(sep=None, maxsplit=0))
+    |
+    = help: Replace with list literal
+
+ℹ Safe fix
+125 125 | print("".rsplit(sep=None, maxsplit=0))
+126 126 | print(" ".rsplit(maxsplit=0))
+127 127 | print(" ".rsplit(sep=None, maxsplit=0))
+128     |-print(" x ".rsplit(maxsplit=0))
+    128 |+print([" x"])
+129 129 | print(" x ".rsplit(maxsplit=0))
+130 130 | print(" x ".rsplit(sep=None, maxsplit=0))
+131 131 | print("  x  ".rsplit(maxsplit=0))
+
+SIM905.py:129:7: SIM905 [*] Consider using a list literal instead of `str.split`
+    |
+127 | print(" ".rsplit(sep=None, maxsplit=0))
+128 | print(" x ".rsplit(maxsplit=0))
+129 | print(" x ".rsplit(maxsplit=0))
+    |       ^^^^^^^^^^^^^^^^^^^^^^^^ SIM905
+130 | print(" x ".rsplit(sep=None, maxsplit=0))
+131 | print("  x  ".rsplit(maxsplit=0))
+    |
+    = help: Replace with list literal
+
+ℹ Safe fix
+126 126 | print(" ".rsplit(maxsplit=0))
+127 127 | print(" ".rsplit(sep=None, maxsplit=0))
+128 128 | print(" x ".rsplit(maxsplit=0))
+129     |-print(" x ".rsplit(maxsplit=0))
+    129 |+print([" x"])
+130 130 | print(" x ".rsplit(sep=None, maxsplit=0))
+131 131 | print("  x  ".rsplit(maxsplit=0))
+132 132 | print("  x  ".rsplit(sep=None, maxsplit=0))
+
+SIM905.py:130:7: SIM905 [*] Consider using a list literal instead of `str.split`
+    |
+128 | print(" x ".rsplit(maxsplit=0))
+129 | print(" x ".rsplit(maxsplit=0))
+130 | print(" x ".rsplit(sep=None, maxsplit=0))
+    |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ SIM905
+131 | print("  x  ".rsplit(maxsplit=0))
+132 | print("  x  ".rsplit(sep=None, maxsplit=0))
+    |
+    = help: Replace with list literal
+
+ℹ Safe fix
+127 127 | print(" ".rsplit(sep=None, maxsplit=0))
+128 128 | print(" x ".rsplit(maxsplit=0))
+129 129 | print(" x ".rsplit(maxsplit=0))
+130     |-print(" x ".rsplit(sep=None, maxsplit=0))
+    130 |+print([" x"])
+131 131 | print("  x  ".rsplit(maxsplit=0))
+132 132 | print("  x  ".rsplit(sep=None, maxsplit=0))
+
+SIM905.py:131:7: SIM905 [*] Consider using a list literal instead of `str.split`
+    |
+129 | print(" x ".rsplit(maxsplit=0))
+130 | print(" x ".rsplit(sep=None, maxsplit=0))
+131 | print("  x  ".rsplit(maxsplit=0))
+    |       ^^^^^^^^^^^^^^^^^^^^^^^^^^ SIM905
+132 | print("  x  ".rsplit(sep=None, maxsplit=0))
+    |
+    = help: Replace with list literal
+
+ℹ Safe fix
+128 128 | print(" x ".rsplit(maxsplit=0))
+129 129 | print(" x ".rsplit(maxsplit=0))
+130 130 | print(" x ".rsplit(sep=None, maxsplit=0))
+131     |-print("  x  ".rsplit(maxsplit=0))
+    131 |+print(["  x"])
+132 132 | print("  x  ".rsplit(sep=None, maxsplit=0))
+
+SIM905.py:132:7: SIM905 [*] Consider using a list literal instead of `str.split`
+    |
+130 | print(" x ".rsplit(sep=None, maxsplit=0))
+131 | print("  x  ".rsplit(maxsplit=0))
+132 | print("  x  ".rsplit(sep=None, maxsplit=0))
+    |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ SIM905
+    |
+    = help: Replace with list literal
+
+ℹ Safe fix
+129 129 | print(" x ".rsplit(maxsplit=0))
+130 130 | print(" x ".rsplit(sep=None, maxsplit=0))
+131 131 | print("  x  ".rsplit(maxsplit=0))
+132     |-print("  x  ".rsplit(sep=None, maxsplit=0))
+    132 |+print(["  x"])

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

@@ -64,7 +64,7 @@ fn is_alias(expr: &Expr, semantic: &SemanticModel) -> bool {
                 [
                     "" | "builtins",
                     "EnvironmentError" | "IOError" | "WindowsError"
-                ] | ["mmap" | "select" | "socket" | "os", "error"]
+                ] | ["mmap" | "resource" | "select" | "socket" | "os", "error"]
             )
         })
 }

crates/ruff_linter/src/rules/pyupgrade/snapshots/ruff_linter__rules__pyupgrade__tests__UP024_2.py.snap

@@ -4,7 +4,7 @@ source: crates/ruff_linter/src/rules/pyupgrade/mod.rs
 UP024_2.py:10:7: UP024 [*] Replace aliased errors with `OSError`
    |
  8 | # Testing the modules
- 9 | import socket, mmap, select
+ 9 | import socket, mmap, select, resource
 10 | raise socket.error
    |       ^^^^^^^^^^^^ UP024
 11 | raise mmap.error
@@ -15,32 +15,33 @@ UP024_2.py:10:7: UP024 [*] Replace aliased errors with `OSError`
 ℹ Safe fix
 7  7  | 
 8  8  | # Testing the modules
-9  9  | import socket, mmap, select
+9  9  | import socket, mmap, select, resource
 10    |-raise socket.error
    10 |+raise OSError
 11 11 | raise mmap.error
 12 12 | raise select.error
-13 13 | 
+13 13 | raise resource.error
 
 UP024_2.py:11:7: UP024 [*] Replace aliased errors with `OSError`
    |
- 9 | import socket, mmap, select
+ 9 | import socket, mmap, select, resource
 10 | raise socket.error
 11 | raise mmap.error
    |       ^^^^^^^^^^ UP024
 12 | raise select.error
+13 | raise resource.error
    |
    = help: Replace `mmap.error` with builtin `OSError`
 
 ℹ Safe fix
 8  8  | # Testing the modules
-9  9  | import socket, mmap, select
+9  9  | import socket, mmap, select, resource
 10 10 | raise socket.error
 11    |-raise mmap.error
    11 |+raise OSError
 12 12 | raise select.error
-13 13 | 
-14 14 | raise socket.error()
+13 13 | raise resource.error
+14 14 | 
 
 UP024_2.py:12:7: UP024 [*] Replace aliased errors with `OSError`
    |
@@ -48,355 +49,416 @@ UP024_2.py:12:7: UP024 [*] Replace aliased errors with `OSError`
 11 | raise mmap.error
 12 | raise select.error
    |       ^^^^^^^^^^^^ UP024
-13 |
-14 | raise socket.error()
+13 | raise resource.error
    |
    = help: Replace `select.error` with builtin `OSError`
 
 ℹ Safe fix
-9  9  | import socket, mmap, select
+9  9  | import socket, mmap, select, resource
 10 10 | raise socket.error
 11 11 | raise mmap.error
 12    |-raise select.error
    12 |+raise OSError
-13 13 | 
-14 14 | raise socket.error()
-15 15 | raise mmap.error(1)
+13 13 | raise resource.error
+14 14 | 
+15 15 | raise socket.error()
 
-UP024_2.py:14:7: UP024 [*] Replace aliased errors with `OSError`
+UP024_2.py:13:7: UP024 [*] Replace aliased errors with `OSError`
    |
+11 | raise mmap.error
 12 | raise select.error
-13 |
-14 | raise socket.error()
+13 | raise resource.error
+   |       ^^^^^^^^^^^^^^ UP024
+14 |
+15 | raise socket.error()
+   |
+   = help: Replace `resource.error` with builtin `OSError`
+
+ℹ Safe fix
+10 10 | raise socket.error
+11 11 | raise mmap.error
+12 12 | raise select.error
+13    |-raise resource.error
+   13 |+raise OSError
+14 14 | 
+15 15 | raise socket.error()
+16 16 | raise mmap.error(1)
+
+UP024_2.py:15:7: UP024 [*] Replace aliased errors with `OSError`
+   |
+13 | raise resource.error
+14 |
+15 | raise socket.error()
    |       ^^^^^^^^^^^^ UP024
-15 | raise mmap.error(1)
-16 | raise select.error(1, 2)
+16 | raise mmap.error(1)
+17 | raise select.error(1, 2)
    |
    = help: Replace `socket.error` with builtin `OSError`
 
 ℹ Safe fix
-11 11 | raise mmap.error
 12 12 | raise select.error
-13 13 | 
-14    |-raise socket.error()
-   14 |+raise OSError()
-15 15 | raise mmap.error(1)
-16 16 | raise select.error(1, 2)
-17 17 | 
+13 13 | raise resource.error
+14 14 | 
+15    |-raise socket.error()
+   15 |+raise OSError()
+16 16 | raise mmap.error(1)
+17 17 | raise select.error(1, 2)
+18 18 | raise resource.error(1, "strerror", "filename")
 
-UP024_2.py:15:7: UP024 [*] Replace aliased errors with `OSError`
+UP024_2.py:16:7: UP024 [*] Replace aliased errors with `OSError`
    |
-14 | raise socket.error()
-15 | raise mmap.error(1)
+15 | raise socket.error()
+16 | raise mmap.error(1)
    |       ^^^^^^^^^^ UP024
-16 | raise select.error(1, 2)
+17 | raise select.error(1, 2)
+18 | raise resource.error(1, "strerror", "filename")
    |
    = help: Replace `mmap.error` with builtin `OSError`
 
 ℹ Safe fix
-12 12 | raise select.error
-13 13 | 
-14 14 | raise socket.error()
-15    |-raise mmap.error(1)
-   15 |+raise OSError(1)
-16 16 | raise select.error(1, 2)
-17 17 | 
-18 18 | raise socket.error(
+13 13 | raise resource.error
+14 14 | 
+15 15 | raise socket.error()
+16    |-raise mmap.error(1)
+   16 |+raise OSError(1)
+17 17 | raise select.error(1, 2)
+18 18 | raise resource.error(1, "strerror", "filename")
+19 19 | 
 
-UP024_2.py:16:7: UP024 [*] Replace aliased errors with `OSError`
+UP024_2.py:17:7: UP024 [*] Replace aliased errors with `OSError`
    |
-14 | raise socket.error()
-15 | raise mmap.error(1)
-16 | raise select.error(1, 2)
+15 | raise socket.error()
+16 | raise mmap.error(1)
+17 | raise select.error(1, 2)
    |       ^^^^^^^^^^^^ UP024
-17 |
-18 | raise socket.error(
+18 | raise resource.error(1, "strerror", "filename")
    |
    = help: Replace `select.error` with builtin `OSError`
 
 ℹ Safe fix
-13 13 | 
-14 14 | raise socket.error()
-15 15 | raise mmap.error(1)
-16    |-raise select.error(1, 2)
-   16 |+raise OSError(1, 2)
-17 17 | 
-18 18 | raise socket.error(
-19 19 |     1,
+14 14 | 
+15 15 | raise socket.error()
+16 16 | raise mmap.error(1)
+17    |-raise select.error(1, 2)
+   17 |+raise OSError(1, 2)
+18 18 | raise resource.error(1, "strerror", "filename")
+19 19 | 
+20 20 | raise socket.error(
 
 UP024_2.py:18:7: UP024 [*] Replace aliased errors with `OSError`
    |
-16 | raise select.error(1, 2)
-17 |
-18 | raise socket.error(
+16 | raise mmap.error(1)
+17 | raise select.error(1, 2)
+18 | raise resource.error(1, "strerror", "filename")
+   |       ^^^^^^^^^^^^^^ UP024
+19 |
+20 | raise socket.error(
+   |
+   = help: Replace `resource.error` with builtin `OSError`
+
+ℹ Safe fix
+15 15 | raise socket.error()
+16 16 | raise mmap.error(1)
+17 17 | raise select.error(1, 2)
+18    |-raise resource.error(1, "strerror", "filename")
+   18 |+raise OSError(1, "strerror", "filename")
+19 19 | 
+20 20 | raise socket.error(
+21 21 |     1,
+
+UP024_2.py:20:7: UP024 [*] Replace aliased errors with `OSError`
+   |
+18 | raise resource.error(1, "strerror", "filename")
+19 |
+20 | raise socket.error(
    |       ^^^^^^^^^^^^ UP024
-19 |     1,
-20 |     2,
+21 |     1,
+22 |     2,
    |
    = help: Replace `socket.error` with builtin `OSError`
 
 ℹ Safe fix
-15 15 | raise mmap.error(1)
-16 16 | raise select.error(1, 2)
-17 17 | 
-18    |-raise socket.error(
-   18 |+raise OSError(
-19 19 |     1,
-20 20 |     2,
-21 21 |     3,
+17 17 | raise select.error(1, 2)
+18 18 | raise resource.error(1, "strerror", "filename")
+19 19 | 
+20    |-raise socket.error(
+   20 |+raise OSError(
+21 21 |     1,
+22 22 |     2,
+23 23 |     3,
 
-UP024_2.py:25:7: UP024 [*] Replace aliased errors with `OSError`
+UP024_2.py:27:7: UP024 [*] Replace aliased errors with `OSError`
    |
-24 | from mmap import error
-25 | raise error
+26 | from mmap import error
+27 | raise error
    |       ^^^^^ UP024
-26 |
-27 | from socket import error
+28 |
+29 | from socket import error
    |
    = help: Replace `error` with builtin `OSError`
 
 ℹ Safe fix
-22 22 | )
-23 23 | 
-24 24 | from mmap import error
-25    |-raise error
-   25 |+raise OSError
-26 26 | 
-27 27 | from socket import error
-28 28 | raise error(1)
+24 24 | )
+25 25 | 
+26 26 | from mmap import error
+27    |-raise error
+   27 |+raise OSError
+28 28 | 
+29 29 | from socket import error
+30 30 | raise error(1)
 
-UP024_2.py:28:7: UP024 [*] Replace aliased errors with `OSError`
+UP024_2.py:30:7: UP024 [*] Replace aliased errors with `OSError`
    |
-27 | from socket import error
-28 | raise error(1)
+29 | from socket import error
+30 | raise error(1)
    |       ^^^^^ UP024
-29 |
-30 | from select import error
+31 |
+32 | from select import error
    |
    = help: Replace `error` with builtin `OSError`
 
 ℹ Safe fix
-25 25 | raise error
-26 26 | 
-27 27 | from socket import error
-28    |-raise error(1)
-   28 |+raise OSError(1)
-29 29 | 
-30 30 | from select import error
-31 31 | raise error(1, 2)
+27 27 | raise error
+28 28 | 
+29 29 | from socket import error
+30    |-raise error(1)
+   30 |+raise OSError(1)
+31 31 | 
+32 32 | from select import error
+33 33 | raise error(1, 2)
 
-UP024_2.py:31:7: UP024 [*] Replace aliased errors with `OSError`
+UP024_2.py:33:7: UP024 [*] Replace aliased errors with `OSError`
    |
-30 | from select import error
-31 | raise error(1, 2)
+32 | from select import error
+33 | raise error(1, 2)
    |       ^^^^^ UP024
-32 |
-33 | # Testing the names
+34 |
+35 | from resource import error
    |
    = help: Replace `error` with builtin `OSError`
 
 ℹ Safe fix
-28 28 | raise error(1)
-29 29 | 
-30 30 | from select import error
-31    |-raise error(1, 2)
-   31 |+raise OSError(1, 2)
-32 32 | 
-33 33 | # Testing the names
-34 34 | raise EnvironmentError
-
-UP024_2.py:34:7: UP024 [*] Replace aliased errors with `OSError`
-   |
-33 | # Testing the names
-34 | raise EnvironmentError
-   |       ^^^^^^^^^^^^^^^^ UP024
-35 | raise IOError
-36 | raise WindowsError
-   |
-   = help: Replace `EnvironmentError` with builtin `OSError`
-
-ℹ Safe fix
-31 31 | raise error(1, 2)
-32 32 | 
-33 33 | # Testing the names
-34    |-raise EnvironmentError
-   34 |+raise OSError
-35 35 | raise IOError
-36 36 | raise WindowsError
-37 37 | 
-
-UP024_2.py:35:7: UP024 [*] Replace aliased errors with `OSError`
-   |
-33 | # Testing the names
-34 | raise EnvironmentError
-35 | raise IOError
-   |       ^^^^^^^ UP024
-36 | raise WindowsError
-   |
-   = help: Replace `IOError` with builtin `OSError`
-
-ℹ Safe fix
-32 32 | 
-33 33 | # Testing the names
-34 34 | raise EnvironmentError
-35    |-raise IOError
-   35 |+raise OSError
-36 36 | raise WindowsError
-37 37 | 
-38 38 | raise EnvironmentError()
+30 30 | raise error(1)
+31 31 | 
+32 32 | from select import error
+33    |-raise error(1, 2)
+   33 |+raise OSError(1, 2)
+34 34 | 
+35 35 | from resource import error
+36 36 | raise error(1, "strerror", "filename")
 
 UP024_2.py:36:7: UP024 [*] Replace aliased errors with `OSError`
    |
-34 | raise EnvironmentError
-35 | raise IOError
-36 | raise WindowsError
-   |       ^^^^^^^^^^^^ UP024
+35 | from resource import error
+36 | raise error(1, "strerror", "filename")
+   |       ^^^^^ UP024
 37 |
-38 | raise EnvironmentError()
+38 | # Testing the names
    |
-   = help: Replace `WindowsError` with builtin `OSError`
+   = help: Replace `error` with builtin `OSError`
 
 ℹ Safe fix
-33 33 | # Testing the names
-34 34 | raise EnvironmentError
-35 35 | raise IOError
-36    |-raise WindowsError
-   36 |+raise OSError
+33 33 | raise error(1, 2)
+34 34 | 
+35 35 | from resource import error
+36    |-raise error(1, "strerror", "filename")
+   36 |+raise OSError(1, "strerror", "filename")
 37 37 | 
-38 38 | raise EnvironmentError()
-39 39 | raise IOError(1)
-
-UP024_2.py:38:7: UP024 [*] Replace aliased errors with `OSError`
-   |
-36 | raise WindowsError
-37 |
-38 | raise EnvironmentError()
-   |       ^^^^^^^^^^^^^^^^ UP024
-39 | raise IOError(1)
-40 | raise WindowsError(1, 2)
-   |
-   = help: Replace `EnvironmentError` with builtin `OSError`
-
-ℹ Safe fix
-35 35 | raise IOError
-36 36 | raise WindowsError
-37 37 | 
-38    |-raise EnvironmentError()
-   38 |+raise OSError()
-39 39 | raise IOError(1)
-40 40 | raise WindowsError(1, 2)
-41 41 | 
+38 38 | # Testing the names
+39 39 | raise EnvironmentError
 
 UP024_2.py:39:7: UP024 [*] Replace aliased errors with `OSError`
    |
-38 | raise EnvironmentError()
-39 | raise IOError(1)
-   |       ^^^^^^^ UP024
-40 | raise WindowsError(1, 2)
+38 | # Testing the names
+39 | raise EnvironmentError
+   |       ^^^^^^^^^^^^^^^^ UP024
+40 | raise IOError
+41 | raise WindowsError
    |
-   = help: Replace `IOError` with builtin `OSError`
+   = help: Replace `EnvironmentError` with builtin `OSError`
 
 ℹ Safe fix
-36 36 | raise WindowsError
+36 36 | raise error(1, "strerror", "filename")
 37 37 | 
-38 38 | raise EnvironmentError()
-39    |-raise IOError(1)
-   39 |+raise OSError(1)
-40 40 | raise WindowsError(1, 2)
-41 41 | 
-42 42 | raise EnvironmentError(
+38 38 | # Testing the names
+39    |-raise EnvironmentError
+   39 |+raise OSError
+40 40 | raise IOError
+41 41 | raise WindowsError
+42 42 | 
 
 UP024_2.py:40:7: UP024 [*] Replace aliased errors with `OSError`
    |
-38 | raise EnvironmentError()
-39 | raise IOError(1)
-40 | raise WindowsError(1, 2)
-   |       ^^^^^^^^^^^^ UP024
-41 |
-42 | raise EnvironmentError(
+38 | # Testing the names
+39 | raise EnvironmentError
+40 | raise IOError
+   |       ^^^^^^^ UP024
+41 | raise WindowsError
    |
-   = help: Replace `WindowsError` with builtin `OSError`
+   = help: Replace `IOError` with builtin `OSError`
 
 ℹ Safe fix
 37 37 | 
-38 38 | raise EnvironmentError()
-39 39 | raise IOError(1)
-40    |-raise WindowsError(1, 2)
-   40 |+raise OSError(1, 2)
-41 41 | 
-42 42 | raise EnvironmentError(
-43 43 |     1,
+38 38 | # Testing the names
+39 39 | raise EnvironmentError
+40    |-raise IOError
+   40 |+raise OSError
+41 41 | raise WindowsError
+42 42 | 
+43 43 | raise EnvironmentError()
 
-UP024_2.py:42:7: UP024 [*] Replace aliased errors with `OSError`
+UP024_2.py:41:7: UP024 [*] Replace aliased errors with `OSError`
    |
-40 | raise WindowsError(1, 2)
-41 |
-42 | raise EnvironmentError(
-   |       ^^^^^^^^^^^^^^^^ UP024
-43 |     1,
-44 |     2,
-   |
-   = help: Replace `EnvironmentError` with builtin `OSError`
-
-ℹ Safe fix
-39 39 | raise IOError(1)
-40 40 | raise WindowsError(1, 2)
-41 41 | 
-42    |-raise EnvironmentError(
-   42 |+raise OSError(
-43 43 |     1,
-44 44 |     2,
-45 45 |     3,
-
-UP024_2.py:48:7: UP024 [*] Replace aliased errors with `OSError`
-   |
-46 | )
-47 |
-48 | raise WindowsError
+39 | raise EnvironmentError
+40 | raise IOError
+41 | raise WindowsError
    |       ^^^^^^^^^^^^ UP024
-49 | raise EnvironmentError(1)
-50 | raise IOError(1, 2)
+42 |
+43 | raise EnvironmentError()
    |
    = help: Replace `WindowsError` with builtin `OSError`
 
 ℹ Safe fix
-45 45 |     3,
-46 46 | )
-47 47 | 
-48    |-raise WindowsError
-   48 |+raise OSError
-49 49 | raise EnvironmentError(1)
-50 50 | raise IOError(1, 2)
+38 38 | # Testing the names
+39 39 | raise EnvironmentError
+40 40 | raise IOError
+41    |-raise WindowsError
+   41 |+raise OSError
+42 42 | 
+43 43 | raise EnvironmentError()
+44 44 | raise IOError(1)
 
-UP024_2.py:49:7: UP024 [*] Replace aliased errors with `OSError`
+UP024_2.py:43:7: UP024 [*] Replace aliased errors with `OSError`
    |
-48 | raise WindowsError
-49 | raise EnvironmentError(1)
+41 | raise WindowsError
+42 |
+43 | raise EnvironmentError()
    |       ^^^^^^^^^^^^^^^^ UP024
-50 | raise IOError(1, 2)
+44 | raise IOError(1)
+45 | raise WindowsError(1, 2)
    |
    = help: Replace `EnvironmentError` with builtin `OSError`
 
 ℹ Safe fix
-46 46 | )
-47 47 | 
-48 48 | raise WindowsError
-49    |-raise EnvironmentError(1)
-   49 |+raise OSError(1)
-50 50 | raise IOError(1, 2)
+40 40 | raise IOError
+41 41 | raise WindowsError
+42 42 | 
+43    |-raise EnvironmentError()
+   43 |+raise OSError()
+44 44 | raise IOError(1)
+45 45 | raise WindowsError(1, 2)
+46 46 | 
 
-UP024_2.py:50:7: UP024 [*] Replace aliased errors with `OSError`
+UP024_2.py:44:7: UP024 [*] Replace aliased errors with `OSError`
    |
-48 | raise WindowsError
-49 | raise EnvironmentError(1)
-50 | raise IOError(1, 2)
+43 | raise EnvironmentError()
+44 | raise IOError(1)
+   |       ^^^^^^^ UP024
+45 | raise WindowsError(1, 2)
+   |
+   = help: Replace `IOError` with builtin `OSError`
+
+ℹ Safe fix
+41 41 | raise WindowsError
+42 42 | 
+43 43 | raise EnvironmentError()
+44    |-raise IOError(1)
+   44 |+raise OSError(1)
+45 45 | raise WindowsError(1, 2)
+46 46 | 
+47 47 | raise EnvironmentError(
+
+UP024_2.py:45:7: UP024 [*] Replace aliased errors with `OSError`
+   |
+43 | raise EnvironmentError()
+44 | raise IOError(1)
+45 | raise WindowsError(1, 2)
+   |       ^^^^^^^^^^^^ UP024
+46 |
+47 | raise EnvironmentError(
+   |
+   = help: Replace `WindowsError` with builtin `OSError`
+
+ℹ Safe fix
+42 42 | 
+43 43 | raise EnvironmentError()
+44 44 | raise IOError(1)
+45    |-raise WindowsError(1, 2)
+   45 |+raise OSError(1, 2)
+46 46 | 
+47 47 | raise EnvironmentError(
+48 48 |     1,
+
+UP024_2.py:47:7: UP024 [*] Replace aliased errors with `OSError`
+   |
+45 | raise WindowsError(1, 2)
+46 |
+47 | raise EnvironmentError(
+   |       ^^^^^^^^^^^^^^^^ UP024
+48 |     1,
+49 |     2,
+   |
+   = help: Replace `EnvironmentError` with builtin `OSError`
+
+ℹ Safe fix
+44 44 | raise IOError(1)
+45 45 | raise WindowsError(1, 2)
+46 46 | 
+47    |-raise EnvironmentError(
+   47 |+raise OSError(
+48 48 |     1,
+49 49 |     2,
+50 50 |     3,
+
+UP024_2.py:53:7: UP024 [*] Replace aliased errors with `OSError`
+   |
+51 | )
+52 |
+53 | raise WindowsError
+   |       ^^^^^^^^^^^^ UP024
+54 | raise EnvironmentError(1)
+55 | raise IOError(1, 2)
+   |
+   = help: Replace `WindowsError` with builtin `OSError`
+
+ℹ Safe fix
+50 50 |     3,
+51 51 | )
+52 52 | 
+53    |-raise WindowsError
+   53 |+raise OSError
+54 54 | raise EnvironmentError(1)
+55 55 | raise IOError(1, 2)
+
+UP024_2.py:54:7: UP024 [*] Replace aliased errors with `OSError`
+   |
+53 | raise WindowsError
+54 | raise EnvironmentError(1)
+   |       ^^^^^^^^^^^^^^^^ UP024
+55 | raise IOError(1, 2)
+   |
+   = help: Replace `EnvironmentError` with builtin `OSError`
+
+ℹ Safe fix
+51 51 | )
+52 52 | 
+53 53 | raise WindowsError
+54    |-raise EnvironmentError(1)
+   54 |+raise OSError(1)
+55 55 | raise IOError(1, 2)
+
+UP024_2.py:55:7: UP024 [*] Replace aliased errors with `OSError`
+   |
+53 | raise WindowsError
+54 | raise EnvironmentError(1)
+55 | raise IOError(1, 2)
    |       ^^^^^^^ UP024
    |
    = help: Replace `IOError` with builtin `OSError`
 
 ℹ Safe fix
-47 47 | 
-48 48 | raise WindowsError
-49 49 | raise EnvironmentError(1)
-50    |-raise IOError(1, 2)
-   50 |+raise OSError(1, 2)
+52 52 | 
+53 53 | raise WindowsError
+54 54 | raise EnvironmentError(1)
+55    |-raise IOError(1, 2)
+   55 |+raise OSError(1, 2)

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

@@ -29,6 +29,14 @@ use crate::{checkers::ast::Checker, importer::ImportRequest};
 /// pairwise(letters)  # ("A", "B"), ("B", "C"), ("C", "D")
 /// ```
 ///
+/// ## Fix safety
+///
+/// The fix is always marked unsafe because it assumes that slicing an object
+/// (e.g., `obj[1:]`) produces a value with the same type and iteration behavior
+/// as the original object, which is not guaranteed for user-defined types that
+/// override `__getitem__` without properly handling slices. Moreover, the fix
+/// could delete comments.
+///
 /// ## References
 /// - [Python documentation: `itertools.pairwise`](https://docs.python.org/3/library/itertools.html#itertools.pairwise)
 #[derive(ViolationMetadata)]

crates/ruff_python_ast/src/visitor/transformer.rs

@@ -234,9 +234,6 @@ pub fn walk_stmt<V: Transformer + ?Sized>(visitor: &V, stmt: &mut Stmt) {
             visitor.visit_expr(test);
             visitor.visit_body(body);
             for clause in elif_else_clauses {
-                if let Some(test) = &mut clause.test {
-                    visitor.visit_expr(test);
-                }
                 walk_elif_else_clause(visitor, clause);
             }
         }

crates/ty/CONTRIBUTING.md

@@ -0,0 +1,141 @@
+# Contributing to ty
+
+Welcome! We're happy to have you here. Thank you in advance for your contribution to ty.
+
+> [!NOTE]
+>
+> This guide is for ty. If you're looking to contribute to Ruff, please see
+> [the Ruff contributing guide](../../CONTRIBUTING.md).
+
+## The Basics
+
+We welcome contributions in the form of pull requests.
+
+For small changes (e.g., bug fixes), feel free to submit a PR.
+
+For larger changes (e.g. new diagnostics, new functionality, new configuration options), consider
+creating an [**issue**](https://github.com/astral-sh/ty/issues) outlining your proposed change.
+You can also join us on [Discord](https://discord.com/invite/astral-sh) to discuss your idea with the
+community. We've labeled [beginner-friendly tasks](https://github.com/astral-sh/ty/issues?q=is%3Aissue+is%3Aopen+label%3A%22help+wanted%22)
+in the issue tracker, along with [bugs](https://github.com/astral-sh/ty/issues?q=is%3Aissue+is%3Aopen+label%3Abug)
+that are ready for contributions.
+
+### Prerequisites
+
+ty is written in Rust. You'll need to install the
+[Rust toolchain](https://www.rust-lang.org/tools/install) for development.
+
+You'll need [uv](https://docs.astral.sh/uv/getting-started/installation/) (or `pipx` and `pip`) to
+run Python utility commands.
+
+You can optionally install pre-commit hooks to automatically run the validation checks
+when making a commit:
+
+```shell
+uv tool install pre-commit
+pre-commit install
+```
+
+We recommend [nextest](https://nexte.st/) to run ty's test suite (via `cargo nextest run`),
+though it's not strictly necessary:
+
+```shell
+cargo install cargo-nextest --locked
+```
+
+Throughout this guide, any usages of `cargo test` can be replaced with `cargo nextest run`,
+if you choose to install `nextest`.
+
+### Development
+
+After cloning the repository, run ty locally from the repository root with:
+
+```shell
+cargo run --bin ty -- check --project /path/to/project/
+```
+
+Prior to opening a pull request, ensure that your code has been auto-formatted,
+and that it passes both the lint and test validation checks:
+
+```shell
+cargo clippy --workspace --all-targets --all-features -- -D warnings  # Rust linting
+cargo test  # Rust testing
+uvx pre-commit run --all-files --show-diff-on-failure  # Rust and Python formatting, Markdown and Python linting, etc.
+```
+
+These checks will run on GitHub Actions when you open your pull request, but running them locally
+will save you time and expedite the merge process.
+
+If you're using VS Code, you can also install the recommended [rust-analyzer](https://marketplace.visualstudio.com/items?itemName=rust-lang.rust-analyzer) extension to get these checks while editing.
+
+Include the text `[ty]` at the beginning of your pull request title, to distinguish ty pull requests
+from Ruff ones.
+
+Your pull request will be reviewed by a maintainer, which may involve a few rounds of iteration
+prior to merging.
+
+### Debugging ty
+
+ty can optionally emit extensive tracing output, which can be very useful in understanding its
+operation and debugging issues; see [`crates/ty/docs/tracing.md`](./docs/tracing.md) for details.
+
+### Project Structure
+
+The codebase is structured as a monorepo with a [flat crate structure](https://matklad.github.io/2021/08/22/large-rust-workspaces.html),
+such that all crates are contained in a flat `crates` directory.
+
+The vast majority of ty's code lives in the `ty_python_semantic` crate (located at
+`crates/ty_python_semantic`). As a contributor, that's the crate that'll probably be most relevant
+to you.
+
+At the time of writing, the repository includes the following ty-specific crates (in addition to
+crates shared with Ruff, such as `ruff_db`, `ruff_python_ast`, and `ruff_python_parser`):
+
+- `ty_python_semantic`: The core type checker, which includes the type inference engine and
+    semantic analysis.
+- `ty_test`: The Markdown-based test framework for ty, "mdtest".
+- `ty`: The command-line interface.
+- `ty_ide`: IDE features (hover, go-to-definition, autocomplete) for the language server.
+- `ty_project`: Discovery and representation of a Python project to be checked by ty.
+- `ty_server`: The ty language server.
+- `ty_vendored`: A vendored copy of [typeshed](https://github.com/python/typeshed), which holds type
+    annotations for the Python standard library.
+- `ty_wasm`: library crate for exposing ty as a WebAssembly module. Powers the
+    [ty Playground](https://play.ty.dev/).
+
+## Writing tests
+
+Core type checking tests are written as Markdown code blocks.
+They can be found in [`crates/ty_python_semantic/resources/mdtest`][resources-mdtest].
+See [`crates/ty_test/README.md`][mdtest-readme] for more information
+on the test framework itself.
+
+Any ty pull request to improve ty's type inference or type checking logic should include mdtests
+demonstrating the effect of the change.
+
+We write mdtests in a "literate" style, with prose explaining the motivation of each test, and any
+context necessary to understand the feature being demonstrated.
+
+### Property tests
+
+ty uses property-based testing to test the core type relations. These tests are located in
+[`crates/ty_python_semantic/src/types/property_tests.rs`](../ty_python_semantic/src/types/property_tests.rs).
+
+The property tests do not run in CI on every PR, just once daily. It is advisable to run them
+locally after modifying core type relation methods (`is_subtype_of`, `is_equivalent_to`, etc.) to
+ensure that the changes do not break any of the properties.
+
+## Ecosystem CI (mypy-primer)
+
+GitHub Actions will run your changes against a number of real-world projects from GitHub and
+report on any linter or formatter differences. See [`crates/ty/docs/mypy_primer.md`](./docs/mypy_primer.md)
+for instructions on running these checks locally.
+
+## Coding guidelines
+
+We use the [Salsa](https:://github.com/salsa-rs/salsa) library for incremental computation. Many
+methods take a Salsa database (usually `db: &'db dyn Db`) as an argument. This should always be the
+first argument (or second after `self`).
+
+[mdtest-readme]: ../ty_test/README.md
+[resources-mdtest]: ../ty_python_semantic/resources/mdtest

crates/ty/README.md

@@ -1,25 +1,9 @@
 # ty
 
 ty is an extremely fast type checker.
-Currently, it is a work-in-progress and not ready for user testing.
+Currently, it is a work-in-progress and not ready for production use.
 
-ty is designed to prioritize good type inference, even in unannotated code,
-and aims to avoid false positives.
+The Rust code for ty lives in this repository; see [CONTRIBUTING.md](CONTRIBUTING.md) for more
+information on contributing to ty.
 
-While ty will produce similar results to mypy and pyright on many codebases,
-100% compatibility with these tools is a non-goal.
-On some codebases, ty's design decisions lead to different outcomes
-than you would get from running one of these more established tools.
-
-## Contributing
-
-Core type checking tests are written as Markdown code blocks.
-They can be found in [`ty_python_semantic/resources/mdtest`][resources-mdtest].
-See [`ty_test/README.md`][mdtest-readme] for more information
-on the test framework itself.
-
-The list of open issues can be found [here][open-issues].
-
-[mdtest-readme]: ../ty_test/README.md
-[open-issues]: https://github.com/astral-sh/ty/issues
-[resources-mdtest]: ../ty_python_semantic/resources/mdtest
+See [the ty repo](https://github.com/astral-sh/ty) for ty documentation and releases.

crates/ty/docs/cli.md

@@ -30,7 +30,7 @@ ty check [OPTIONS] [PATH]...
 
 <h3 class="cli-reference">Arguments</h3>
 
-<dl class="cli-reference"><dt id="ty-check--paths"><a href="#ty-check--paths"<code>PATHS</code></a></dt><dd><p>List of files or directories to check [default: the project root]</p>
+<dl class="cli-reference"><dt id="ty-check--paths"><a href="#ty-check--paths"><code>PATHS</code></a></dt><dd><p>List of files or directories to check [default: the project root]</p>
 </dd></dl>
 
 <h3 class="cli-reference">Options</h3>
@@ -125,7 +125,7 @@ ty generate-shell-completion <SHELL>
 
 <h3 class="cli-reference">Arguments</h3>
 
-<dl class="cli-reference"><dt id="ty-generate-shell-completion--shell"><a href="#ty-generate-shell-completion--shell"<code>SHELL</code></a></dt></dl>
+<dl class="cli-reference"><dt id="ty-generate-shell-completion--shell"><a href="#ty-generate-shell-completion--shell"><code>SHELL</code></a></dt></dl>
 
 <h3 class="cli-reference">Options</h3>
 

crates/ty/docs/configuration.md

@@ -22,7 +22,7 @@ respect-ignore-files = false
 
 Configures the enabled rules and their severity.
 
-See [the rules documentation](https://github.com/astral-sh/ty/blob/main/docs/rules.md) for a list of all available rules.
+See [the rules documentation](https://ty.dev/rules) for a list of all available rules.
 
 Valid severities are:
 

crates/ty/docs/rules.md

@@ -50,7 +50,7 @@ Calling a non-callable object will raise a `TypeError` at runtime.
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20call-non-callable)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L84)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L85)
 </details>
 
 ## `conflicting-argument-forms`
@@ -81,7 +81,7 @@ f(int)  # error
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20conflicting-argument-forms)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L115)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L116)
 </details>
 
 ## `conflicting-declarations`
@@ -111,7 +111,7 @@ a = 1
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20conflicting-declarations)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L141)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L142)
 </details>
 
 ## `conflicting-metaclass`
@@ -142,7 +142,7 @@ class C(A, B): ...
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20conflicting-metaclass)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L166)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L167)
 </details>
 
 ## `cyclic-class-definition`
@@ -173,7 +173,7 @@ class B(A): ...
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20cyclic-class-definition)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L192)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L193)
 </details>
 
 ## `division-by-zero`
@@ -196,7 +196,7 @@ Dividing by zero raises a `ZeroDivisionError` at runtime.
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20division-by-zero)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L218)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L219)
 </details>
 
 ## `duplicate-base`
@@ -222,7 +222,7 @@ class B(A, A): ...
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20duplicate-base)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L236)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L237)
 </details>
 
 ## `escape-character-in-forward-annotation`
@@ -359,7 +359,7 @@ TypeError: multiple bases have instance lay-out conflict
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20incompatible-slots)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L257)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L258)
 </details>
 
 ## `inconsistent-mro`
@@ -388,7 +388,7 @@ class C(A, B): ...
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20inconsistent-mro)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L343)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L344)
 </details>
 
 ## `index-out-of-bounds`
@@ -413,7 +413,7 @@ t[3]  # IndexError: tuple index out of range
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20index-out-of-bounds)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L367)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L368)
 </details>
 
 ## `invalid-argument-type`
@@ -439,7 +439,7 @@ func("foo")  # error: [invalid-argument-type]
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-argument-type)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L387)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L388)
 </details>
 
 ## `invalid-assignment`
@@ -466,7 +466,7 @@ a: int = ''
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-assignment)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L427)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L428)
 </details>
 
 ## `invalid-attribute-access`
@@ -499,7 +499,7 @@ C.instance_var = 3  # error: Cannot assign to instance variable
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-attribute-access)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1311)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1312)
 </details>
 
 ## `invalid-base`
@@ -513,7 +513,7 @@ TODO #14889
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-base)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L449)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L450)
 </details>
 
 ## `invalid-context-manager`
@@ -539,7 +539,7 @@ with 1:
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-context-manager)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L458)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L459)
 </details>
 
 ## `invalid-declaration`
@@ -567,7 +567,7 @@ a: str
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-declaration)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L479)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L480)
 </details>
 
 ## `invalid-exception-caught`
@@ -608,7 +608,7 @@ except ZeroDivisionError:
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-exception-caught)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L502)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L503)
 </details>
 
 ## `invalid-generic-class`
@@ -639,7 +639,7 @@ class C[U](Generic[T]): ...
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-generic-class)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L538)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L539)
 </details>
 
 ## `invalid-legacy-type-variable`
@@ -672,7 +672,7 @@ def f(t: TypeVar("U")): ...
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-legacy-type-variable)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L564)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L565)
 </details>
 
 ## `invalid-metaclass`
@@ -704,7 +704,7 @@ class B(metaclass=f): ...
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-metaclass)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L592)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L593)
 </details>
 
 ## `invalid-overload`
@@ -752,7 +752,7 @@ def foo(x: int) -> int: ...
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-overload)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L619)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L620)
 </details>
 
 ## `invalid-parameter-default`
@@ -777,7 +777,7 @@ def f(a: int = ''): ...
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-parameter-default)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L662)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L663)
 </details>
 
 ## `invalid-protocol`
@@ -810,7 +810,7 @@ TypeError: Protocols can only inherit from other protocols, got <class 'int'>
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-protocol)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L315)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L316)
 </details>
 
 ## `invalid-raise`
@@ -858,7 +858,7 @@ def g():
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-raise)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L682)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L683)
 </details>
 
 ## `invalid-return-type`
@@ -882,7 +882,7 @@ def func() -> int:
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-return-type)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L408)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L409)
 </details>
 
 ## `invalid-super-argument`
@@ -926,7 +926,7 @@ super(B, A)  # error: `A` does not satisfy `issubclass(A, B)`
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-super-argument)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L725)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L726)
 </details>
 
 ## `invalid-syntax-in-forward-annotation`
@@ -969,7 +969,7 @@ TYPE_CHECKING = ''
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-type-checking-constant)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L764)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L765)
 </details>
 
 ## `invalid-type-form`
@@ -997,7 +997,7 @@ b: Annotated[int]  # `Annotated` expects at least two arguments
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-type-form)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L788)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L789)
 </details>
 
 ## `invalid-type-variable-constraints`
@@ -1031,7 +1031,7 @@ T = TypeVar('T', bound=str)  # valid bound TypeVar
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-type-variable-constraints)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L811)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L812)
 </details>
 
 ## `missing-argument`
@@ -1055,7 +1055,7 @@ func()  # TypeError: func() missing 1 required positional argument: 'x'
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20missing-argument)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L840)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L841)
 </details>
 
 ## `no-matching-overload`
@@ -1083,7 +1083,7 @@ func("string")  # error: [no-matching-overload]
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20no-matching-overload)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L859)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L860)
 </details>
 
 ## `non-subscriptable`
@@ -1106,7 +1106,7 @@ Subscripting an object that does not support it will raise a `TypeError` at runt
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20non-subscriptable)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L882)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L883)
 </details>
 
 ## `not-iterable`
@@ -1131,7 +1131,7 @@ for i in 34:  # TypeError: 'int' object is not iterable
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20not-iterable)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L900)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L901)
 </details>
 
 ## `parameter-already-assigned`
@@ -1157,7 +1157,7 @@ f(1, x=2)  # Error raised here
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20parameter-already-assigned)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L951)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L952)
 </details>
 
 ## `raw-string-type-annotation`
@@ -1216,7 +1216,7 @@ static_assert(int(2.0 * 3.0) == 6)  # error: does not have a statically known tr
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20static-assert-error)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1287)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1288)
 </details>
 
 ## `subclass-of-final-class`
@@ -1244,7 +1244,7 @@ class B(A): ...  # Error raised here
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20subclass-of-final-class)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1042)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1043)
 </details>
 
 ## `too-many-positional-arguments`
@@ -1270,7 +1270,7 @@ f("foo")  # Error raised here
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20too-many-positional-arguments)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1087)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1088)
 </details>
 
 ## `type-assertion-failure`
@@ -1297,7 +1297,7 @@ def _(x: int):
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20type-assertion-failure)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1065)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1066)
 </details>
 
 ## `unavailable-implicit-super-arguments`
@@ -1341,7 +1341,7 @@ class A:
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20unavailable-implicit-super-arguments)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1108)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1109)
 </details>
 
 ## `unknown-argument`
@@ -1367,7 +1367,7 @@ f(x=1, y=2)  # Error raised here
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20unknown-argument)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1165)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1166)
 </details>
 
 ## `unresolved-attribute`
@@ -1394,7 +1394,7 @@ A().foo  # AttributeError: 'A' object has no attribute 'foo'
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20unresolved-attribute)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1186)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1187)
 </details>
 
 ## `unresolved-import`
@@ -1418,7 +1418,7 @@ import foo  # ModuleNotFoundError: No module named 'foo'
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20unresolved-import)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1208)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1209)
 </details>
 
 ## `unresolved-reference`
@@ -1442,7 +1442,7 @@ print(x)  # NameError: name 'x' is not defined
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20unresolved-reference)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1227)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1228)
 </details>
 
 ## `unsupported-bool-conversion`
@@ -1478,7 +1478,7 @@ b1 < b2 < b1  # exception raised here
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20unsupported-bool-conversion)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L920)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L921)
 </details>
 
 ## `unsupported-operator`
@@ -1505,7 +1505,7 @@ A() + A()  # TypeError: unsupported operand type(s) for +: 'A' and 'A'
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20unsupported-operator)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1246)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1247)
 </details>
 
 ## `zero-stepsize-in-slice`
@@ -1529,7 +1529,7 @@ l[1:10:0]  # ValueError: slice step cannot be zero
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20zero-stepsize-in-slice)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1268)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1269)
 </details>
 
 ## `call-possibly-unbound-method`
@@ -1547,7 +1547,7 @@ Calling an unbound method will raise an `AttributeError` at runtime.
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20call-possibly-unbound-method)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L102)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L103)
 </details>
 
 ## `invalid-ignore-comment`
@@ -1603,7 +1603,7 @@ A.c  # AttributeError: type object 'A' has no attribute 'c'
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20possibly-unbound-attribute)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L972)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L973)
 </details>
 
 ## `possibly-unbound-import`
@@ -1634,7 +1634,7 @@ from module import a  # ImportError: cannot import name 'a' from 'module'
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20possibly-unbound-import)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L994)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L995)
 </details>
 
 ## `redundant-cast`
@@ -1660,7 +1660,7 @@ cast(int, f())  # Redundant
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20redundant-cast)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1339)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1340)
 </details>
 
 ## `undefined-reveal`
@@ -1683,7 +1683,7 @@ reveal_type(1)  # NameError: name 'reveal_type' is not defined
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20undefined-reveal)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1147)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1148)
 </details>
 
 ## `unknown-rule`
@@ -1740,7 +1740,7 @@ print(x)  # NameError: name 'x' is not defined
 
 ### Links
 * [Related issues](https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20possibly-unresolved-reference)
-* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1020)
+* [View source](https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1021)
 </details>
 
 ## `unused-ignore-comment`

crates/ty_project/src/metadata/options.rs

@@ -31,7 +31,7 @@ pub struct Options {
 
     /// Configures the enabled rules and their severity.
     ///
-    /// See [the rules documentation](https://github.com/astral-sh/ty/blob/main/docs/rules.md) for a list of all available rules.
+    /// See [the rules documentation](https://ty.dev/rules) for a list of all available rules.
     ///
     /// Valid severities are:
     ///

crates/ty_python_semantic/resources/mdtest/annotations/self.md

@@ -19,7 +19,7 @@ class Shape:
         reveal_type(self)  # revealed: Self
         return self
 
-    def nested_type(self) -> list[Self]:
+    def nested_type(self: Self) -> list[Self]:
         return [self]
 
     def nested_func(self: Self) -> Self:
@@ -33,9 +33,7 @@ class Shape:
         reveal_type(self)  # revealed: Unknown
         return self
 
-# TODO: should be `list[Shape]`
-reveal_type(Shape().nested_type())  # revealed: list[Self]
-
+reveal_type(Shape().nested_type())  # revealed: list[Shape]
 reveal_type(Shape().nested_func())  # revealed: Shape
 
 class Circle(Shape):

crates/ty_python_semantic/resources/mdtest/annotations/starred.md

@@ -13,11 +13,10 @@ from typing_extensions import TypeVarTuple
 Ts = TypeVarTuple("Ts")
 
 def append_int(*args: *Ts) -> tuple[*Ts, int]:
-    # TODO: tuple[*Ts]
-    reveal_type(args)  # revealed: tuple[Unknown, ...]
+    reveal_type(args)  # revealed: @Todo(PEP 646)
 
     return (*args, 1)
 
 # TODO should be tuple[Literal[True], Literal["a"], int]
-reveal_type(append_int(True, "a"))  # revealed: @Todo(full tuple[...] support)
+reveal_type(append_int(True, "a"))  # revealed: @Todo(PEP 646)
 ```

crates/ty_python_semantic/resources/mdtest/annotations/unsupported_special_forms.md

@@ -15,16 +15,13 @@ R_co = TypeVar("R_co", covariant=True)
 Alias: TypeAlias = int
 
 def f(*args: Unpack[Ts]) -> tuple[Unpack[Ts]]:
-    # TODO: should understand the annotation
-    reveal_type(args)  # revealed: tuple[Unknown, ...]
-
+    reveal_type(args)  # revealed: tuple[@Todo(`Unpack[]` special form), ...]
     reveal_type(Alias)  # revealed: @Todo(Support for `typing.TypeAlias`)
 
 def g() -> TypeGuard[int]: ...
 def h() -> TypeIs[int]: ...
 def i(callback: Callable[Concatenate[int, P], R_co], *args: P.args, **kwargs: P.kwargs) -> R_co:
-    # TODO: should understand the annotation
-    reveal_type(args)  # revealed: tuple[Unknown, ...]
+    reveal_type(args)  # revealed: tuple[@Todo(Support for `typing.ParamSpec`), ...]
     reveal_type(kwargs)  # revealed: dict[str, @Todo(Support for `typing.ParamSpec`)]
     return callback(42, *args, **kwargs)
 

crates/ty_python_semantic/resources/mdtest/assignment/annotations.md

@@ -56,13 +56,12 @@ reveal_type(a)  # revealed: tuple[()]
 reveal_type(b)  # revealed: tuple[int]
 reveal_type(c)  # revealed: tuple[str, int]
 reveal_type(d)  # revealed: tuple[tuple[str, str], tuple[int, int]]
+reveal_type(e)  # revealed: tuple[str, ...]
+
+reveal_type(f)  # revealed: @Todo(PEP 646)
+reveal_type(g)  # revealed: @Todo(PEP 646)
 
-# TODO: homogeneous tuples, PEP-646 tuples, generics
-reveal_type(e)  # revealed: @Todo(full tuple[...] support)
-reveal_type(f)  # revealed: @Todo(full tuple[...] support)
-reveal_type(g)  # revealed: @Todo(full tuple[...] support)
 reveal_type(h)  # revealed: tuple[list[int], list[int]]
-
 reveal_type(i)  # revealed: tuple[str | int, str | int]
 reveal_type(j)  # revealed: tuple[str | int]
 ```

crates/ty_python_semantic/resources/mdtest/attributes.md

@@ -1462,6 +1462,14 @@ Instance attributes also take precedence over the `__getattr__` method:
 reveal_type(c.instance_attr)  # revealed: str
 ```
 
+Importantly, `__getattr__` is only called if attributes are accessed on instances, not if they are
+accessed on the class itself:
+
+```py
+# error: [unresolved-attribute]
+CustomGetAttr.whatever
+```
+
 ### Type of the `name` parameter
 
 If the `name` parameter of the `__getattr__` method is annotated with a (union of) literal type(s),
@@ -1676,7 +1684,7 @@ functions are instances of that class:
 ```py
 def f(): ...
 
-reveal_type(f.__defaults__)  # revealed: @Todo(full tuple[...] support) | None
+reveal_type(f.__defaults__)  # revealed: tuple[Any, ...] | None
 reveal_type(f.__kwdefaults__)  # revealed: dict[str, Any] | None
 ```
 
@@ -1730,7 +1738,7 @@ All attribute access on literal `bytes` types is currently delegated to `builtin
 ```py
 # revealed: bound method Literal[b"foo"].join(iterable_of_bytes: Iterable[@Todo(Support for `typing.TypeAlias`)], /) -> bytes
 reveal_type(b"foo".join)
-# revealed: bound method Literal[b"foo"].endswith(suffix: @Todo(Support for `typing.TypeAlias`), start: SupportsIndex | None = ellipsis, end: SupportsIndex | None = ellipsis, /) -> bool
+# revealed: bound method Literal[b"foo"].endswith(suffix: @Todo(Support for `typing.TypeAlias`) | tuple[@Todo(Support for `typing.TypeAlias`), ...], start: SupportsIndex | None = ellipsis, end: SupportsIndex | None = ellipsis, /) -> bool
 reveal_type(b"foo".endswith)
 ```
 

crates/ty_python_semantic/resources/mdtest/binary/instances.md

@@ -317,8 +317,7 @@ reveal_type(A() + b"foo")  # revealed: A
 reveal_type(b"foo" + A())  # revealed: bytes
 
 reveal_type(A() + ())  # revealed: A
-# TODO this should be `A`, since `tuple.__add__` doesn't support `A` instances
-reveal_type(() + A())  # revealed: @Todo(full tuple[...] support)
+reveal_type(() + A())  # revealed: A
 
 literal_string_instance = "foo" * 1_000_000_000
 # the test is not testing what it's meant to be testing if this isn't a `LiteralString`:

crates/ty_python_semantic/resources/mdtest/binary/tuples.md

@@ -17,6 +17,6 @@ def _(x: tuple[int, str], y: tuple[None, tuple[int]]):
 
 ```py
 def _(x: tuple[int, ...], y: tuple[str, ...]):
-    reveal_type(x + y)  # revealed: @Todo(full tuple[...] support)
-    reveal_type(x + (1, 2))  # revealed: @Todo(full tuple[...] support)
+    reveal_type(x + y)  # revealed: tuple[int | str, ...]
+    reveal_type(x + (1, 2))  # revealed: tuple[int, ...]
 ```

crates/ty_python_semantic/resources/mdtest/call/builtins.md

@@ -54,7 +54,7 @@ type(b"Foo", (), {})
 # error: [no-matching-overload] "No overload of class `type` matches arguments"
 type("Foo", Base, {})
 
-# TODO: this should be an error
+# error: [no-matching-overload] "No overload of class `type` matches arguments"
 type("Foo", (1, 2), {})
 
 # TODO: this should be an error

crates/ty_python_semantic/resources/mdtest/cycle.md

@@ -13,3 +13,21 @@ def f(x: f):
 
 reveal_type(f)  # revealed: def f(x: Unknown) -> Unknown
 ```
+
+## Unpacking
+
+See: <https://github.com/astral-sh/ty/issues/364>
+
+```py
+class Point:
+    def __init__(self, x: int = 0, y: int = 0) -> None:
+        self.x = x
+        self.y = y
+
+    def replace_with(self, other: "Point") -> None:
+        self.x, self.y = other.x, other.y
+
+p = Point()
+reveal_type(p.x)  # revealed: Unknown | int
+reveal_type(p.y)  # revealed: Unknown | int
+```

crates/ty_python_semantic/resources/mdtest/dataclasses.md

@@ -616,6 +616,25 @@ reveal_type(C.__init__)  # revealed: (field: str | int = int) -> None
 
 To do
 
+## `dataclass.fields`
+
+Dataclasses have `__dataclass_fields__` in them, which makes them a subtype of the
+`DataclassInstance` protocol.
+
+Here, we verify that dataclasses can be passed to `dataclasses.fields` without any errors, and that
+the return type of `dataclasses.fields` is correct.
+
+```py
+from dataclasses import dataclass, fields
+
+@dataclass
+class Foo:
+    x: int
+
+reveal_type(Foo.__dataclass_fields__)  # revealed: dict[str, Field[Any]]
+reveal_type(fields(Foo))  # revealed: tuple[Field[Any], ...]
+```
+
 ## Other special cases
 
 ### `dataclasses.dataclass`

crates/ty_python_semantic/resources/mdtest/diagnostics/no_matching_overload.md

@@ -4,11 +4,277 @@
 
 ## Calls to overloaded functions
 
-TODO: Note that we do not yet support the `@overload` decorator to define overloaded functions in
-real Python code. We are instead testing a special-cased function where we create an overloaded
-signature internally. Update this to an `@overload` function in the Python snippet itself once we
-can.
+```py
+from typing import overload
+
+@overload
+def f(x: int) -> int: ...
+@overload
+def f(x: str) -> str: ...
+def f(x: int | str) -> int | str:
+    return x
+
+f(b"foo")  # error: [no-matching-overload]
+```
+
+## Call to function with many unmatched overloads
+
+Note that it would be fine to use `pow` here as an example of a routine with many overloads, but at
+time of writing (2025-05-14), ty doesn't support some of the type signatures of those overloads.
+Which in turn makes snapshotting a bit annoying, since the output can depend on how ty is compiled
+(because of how `Todo` types are dealt with when `debug_assertions` is enabled versus disabled).
 
 ```py
-type("Foo", ())  # error: [no-matching-overload]
+from typing import overload
+
+class Foo: ...
+
+@overload
+def foo(a: int, b: int, c: int): ...
+@overload
+def foo(a: str, b: int, c: int): ...
+@overload
+def foo(a: int, b: str, c: int): ...
+@overload
+def foo(a: int, b: int, c: str): ...
+@overload
+def foo(a: str, b: str, c: int): ...
+@overload
+def foo(a: int, b: str, c: str): ...
+@overload
+def foo(a: str, b: str, c: str): ...
+@overload
+def foo(a: int, b: int, c: int): ...
+@overload
+def foo(a: float, b: int, c: int): ...
+@overload
+def foo(a: int, b: float, c: int): ...
+@overload
+def foo(a: int, b: int, c: float): ...
+@overload
+def foo(a: float, b: float, c: int): ...
+@overload
+def foo(a: int, b: float, c: float): ...
+@overload
+def foo(a: float, b: float, c: float): ...
+@overload
+def foo(a: str, b: str, c: str): ...
+@overload
+def foo(a: float, b: str, c: str): ...
+@overload
+def foo(a: str, b: float, c: str): ...
+@overload
+def foo(a: str, b: str, c: float): ...
+@overload
+def foo(a: float, b: float, c: str): ...
+@overload
+def foo(a: str, b: float, c: float): ...
+@overload
+def foo(a: float, b: float, c: float): ...
+def foo(a, b, c): ...
+
+foo(Foo(), Foo())  # error: [no-matching-overload]
+```
+
+## Call to function with too many unmatched overloads
+
+This is like the above example, but has an excessive number of overloads to the point that ty will
+cut off the list in the diagnostic and emit a message stating the number of omitted overloads.
+
+```py
+from typing import overload
+
+class Foo: ...
+
+@overload
+def foo(a: int, b: int, c: int): ...
+@overload
+def foo(a: str, b: int, c: int): ...
+@overload
+def foo(a: int, b: str, c: int): ...
+@overload
+def foo(a: int, b: int, c: str): ...
+@overload
+def foo(a: str, b: str, c: int): ...
+@overload
+def foo(a: int, b: str, c: str): ...
+@overload
+def foo(a: str, b: str, c: str): ...
+@overload
+def foo(a: int, b: int, c: int): ...
+@overload
+def foo(a: float, b: int, c: int): ...
+@overload
+def foo(a: int, b: float, c: int): ...
+@overload
+def foo(a: int, b: int, c: float): ...
+@overload
+def foo(a: float, b: float, c: int): ...
+@overload
+def foo(a: int, b: float, c: float): ...
+@overload
+def foo(a: float, b: float, c: float): ...
+@overload
+def foo(a: str, b: str, c: str): ...
+@overload
+def foo(a: float, b: str, c: str): ...
+@overload
+def foo(a: str, b: float, c: str): ...
+@overload
+def foo(a: str, b: str, c: float): ...
+@overload
+def foo(a: float, b: float, c: str): ...
+@overload
+def foo(a: str, b: float, c: float): ...
+@overload
+def foo(a: float, b: float, c: float): ...
+@overload
+def foo(a: list[int], b: list[int], c: list[int]): ...
+@overload
+def foo(a: list[str], b: list[int], c: list[int]): ...
+@overload
+def foo(a: list[int], b: list[str], c: list[int]): ...
+@overload
+def foo(a: list[int], b: list[int], c: list[str]): ...
+@overload
+def foo(a: list[str], b: list[str], c: list[int]): ...
+@overload
+def foo(a: list[int], b: list[str], c: list[str]): ...
+@overload
+def foo(a: list[str], b: list[str], c: list[str]): ...
+@overload
+def foo(a: list[int], b: list[int], c: list[int]): ...
+@overload
+def foo(a: list[float], b: list[int], c: list[int]): ...
+@overload
+def foo(a: list[int], b: list[float], c: list[int]): ...
+@overload
+def foo(a: list[int], b: list[int], c: list[float]): ...
+@overload
+def foo(a: list[float], b: list[float], c: list[int]): ...
+@overload
+def foo(a: list[int], b: list[float], c: list[float]): ...
+@overload
+def foo(a: list[float], b: list[float], c: list[float]): ...
+@overload
+def foo(a: list[str], b: list[str], c: list[str]): ...
+@overload
+def foo(a: list[float], b: list[str], c: list[str]): ...
+@overload
+def foo(a: list[str], b: list[float], c: list[str]): ...
+@overload
+def foo(a: list[str], b: list[str], c: list[float]): ...
+@overload
+def foo(a: list[float], b: list[float], c: list[str]): ...
+@overload
+def foo(a: list[str], b: list[float], c: list[float]): ...
+@overload
+def foo(a: list[float], b: list[float], c: list[float]): ...
+@overload
+def foo(a: bool, b: bool, c: bool): ...
+@overload
+def foo(a: str, b: bool, c: bool): ...
+@overload
+def foo(a: bool, b: str, c: bool): ...
+@overload
+def foo(a: bool, b: bool, c: str): ...
+@overload
+def foo(a: str, b: str, c: bool): ...
+@overload
+def foo(a: bool, b: str, c: str): ...
+@overload
+def foo(a: str, b: str, c: str): ...
+@overload
+def foo(a: int, b: int, c: int): ...
+@overload
+def foo(a: bool, b: int, c: int): ...
+@overload
+def foo(a: int, b: bool, c: int): ...
+@overload
+def foo(a: int, b: int, c: bool): ...
+@overload
+def foo(a: bool, b: bool, c: int): ...
+@overload
+def foo(a: int, b: bool, c: bool): ...
+@overload
+def foo(a: str, b: str, c: str): ...
+@overload
+def foo(a: float, b: bool, c: bool): ...
+@overload
+def foo(a: bool, b: float, c: bool): ...
+@overload
+def foo(a: bool, b: bool, c: float): ...
+@overload
+def foo(a: float, b: float, c: bool): ...
+@overload
+def foo(a: bool, b: float, c: float): ...
+def foo(a, b, c): ...
+
+foo(Foo(), Foo())  # error: [no-matching-overload]
+```
+
+## Calls to overloaded functions with lots of parameters
+
+```py
+from typing import overload
+
+@overload
+def f(
+    lion: int,
+    turtle: int,
+    tortoise: int,
+    goat: int,
+    capybara: int,
+    chicken: int,
+    ostrich: int,
+    gorilla: int,
+    giraffe: int,
+    condor: int,
+    kangaroo: int,
+    anaconda: int,
+    tarantula: int,
+    millipede: int,
+    leopard: int,
+    hyena: int,
+) -> int: ...
+@overload
+def f(
+    lion: str,
+    turtle: str,
+    tortoise: str,
+    goat: str,
+    capybara: str,
+    chicken: str,
+    ostrich: str,
+    gorilla: str,
+    giraffe: str,
+    condor: str,
+    kangaroo: str,
+    anaconda: str,
+    tarantula: str,
+    millipede: str,
+    leopard: str,
+    hyena: str,
+) -> str: ...
+def f(
+    lion: int | str,
+    turtle: int | str,
+    tortoise: int | str,
+    goat: int | str,
+    capybara: int | str,
+    chicken: int | str,
+    ostrict: int | str,
+    gorilla: int | str,
+    giraffe: int | str,
+    condor: int | str,
+    kangaroo: int | str,
+    anaconda: int | str,
+    tarantula: int | str,
+    millipede: int | str,
+    leopard: int | str,
+    hyena: int | str,
+) -> int | str:
+    return 0
+
+f(b"foo")  # error: [no-matching-overload]
 ```

crates/ty_python_semantic/resources/mdtest/diagnostics/unresolved_reference.md

@@ -0,0 +1,14 @@
+# Diagnostics for unresolved references
+
+## New builtin used on old Python version
+
+<!-- snapshot-diagnostics -->
+
+```toml
+[environment]
+python-version = "3.9"
+```
+
+```py
+aiter  # error: [unresolved-reference]
+```

crates/ty_python_semantic/resources/mdtest/directives/assert_never.md

@@ -2,6 +2,8 @@
 
 ## Basic functionality
 
+<!-- snapshot-diagnostics -->
+
 `assert_never` makes sure that the type of the argument is `Never`. If it is not, a
 `type-assertion-failure` diagnostic is emitted.
 
@@ -58,7 +60,7 @@ def if_else_isinstance_error(obj: A | B):
     elif isinstance(obj, C):
         pass
     else:
-        # error: [type-assertion-failure] "Expected type `Never`, got `B & ~A & ~C` instead"
+        # error: [type-assertion-failure] "Argument does not have asserted type `Never`"
         assert_never(obj)
 
 def if_else_singletons_success(obj: Literal[1, "a"] | None):
@@ -79,7 +81,7 @@ def if_else_singletons_error(obj: Literal[1, "a"] | None):
     elif obj is None:
         pass
     else:
-        # error: [type-assertion-failure] "Expected type `Never`, got `Literal["a"]` instead"
+        # error: [type-assertion-failure] "Argument does not have asserted type `Never`"
         assert_never(obj)
 
 def match_singletons_success(obj: Literal[1, "a"] | None):
@@ -92,7 +94,7 @@ def match_singletons_success(obj: Literal[1, "a"] | None):
             pass
         case _ as obj:
             # TODO: Ideally, we would not emit an error here
-            # error: [type-assertion-failure] "Expected type `Never`, got `@Todo"
+            # error: [type-assertion-failure] "Argument does not have asserted type `Never`"
             assert_never(obj)
 
 def match_singletons_error(obj: Literal[1, "a"] | None):
@@ -106,6 +108,6 @@ def match_singletons_error(obj: Literal[1, "a"] | None):
         case _ as obj:
             # TODO: We should emit an error here, but the message should
             # show the type `Literal["a"]` instead of `@Todo(…)`.
-            # error: [type-assertion-failure] "Expected type `Never`, got `@Todo"
+            # error: [type-assertion-failure] "Argument does not have asserted type `Never`"
             assert_never(obj)
 ```

crates/ty_python_semantic/resources/mdtest/directives/assert_type.md

@@ -2,6 +2,8 @@
 
 ## Basic
 
+<!-- snapshot-diagnostics -->
+
 ```py
 from typing_extensions import assert_type
 

crates/ty_python_semantic/resources/mdtest/exception/basic.md

@@ -45,6 +45,8 @@ def foo(
     x: type[AttributeError],
     y: tuple[type[OSError], type[RuntimeError]],
     z: tuple[type[BaseException], ...],
+    zz: tuple[type[TypeError | RuntimeError], ...],
+    zzz: type[BaseException] | tuple[type[BaseException], ...],
 ):
     try:
         help()
@@ -53,8 +55,11 @@ def foo(
     except y as f:
         reveal_type(f)  # revealed: OSError | RuntimeError
     except z as g:
-        # TODO: should be `BaseException`
-        reveal_type(g)  # revealed: @Todo(full tuple[...] support)
+        reveal_type(g)  # revealed: BaseException
+    except zz as h:
+        reveal_type(h)  # revealed: TypeError | RuntimeError
+    except zzz as i:
+        reveal_type(i)  # revealed: BaseException
 ```
 
 ## Invalid exception handlers
@@ -86,9 +91,9 @@ def foo(
     # error: [invalid-exception-caught]
     except y as f:
         reveal_type(f)  # revealed: OSError | RuntimeError | Unknown
+    # error: [invalid-exception-caught]
     except z as g:
-        # TODO: should emit a diagnostic here:
-        reveal_type(g)  # revealed: @Todo(full tuple[...] support)
+        reveal_type(g)  # revealed: Unknown
 ```
 
 ## Object raised is not an exception

crates/ty_python_semantic/resources/mdtest/exception/except_star.md

@@ -22,9 +22,7 @@ except* BaseException as e:
 try:
     help()
 except* OSError as e:
-    # TODO: more precise would be `ExceptionGroup[OSError]` --Alex
-    # (needs homogeneous tuples + generics)
-    reveal_type(e)  # revealed: BaseExceptionGroup[BaseException]
+    reveal_type(e)  # revealed: ExceptionGroup[OSError]
 ```
 
 ## `except*` with multiple exceptions
@@ -33,9 +31,7 @@ except* OSError as e:
 try:
     help()
 except* (TypeError, AttributeError) as e:
-    # TODO: more precise would be `ExceptionGroup[TypeError | AttributeError]` --Alex
-    # (needs homogeneous tuples + generics)
-    reveal_type(e)  # revealed: BaseExceptionGroup[BaseException]
+    reveal_type(e)  # revealed: ExceptionGroup[TypeError | AttributeError]
 ```
 
 ## `except*` with mix of `Exception`s and `BaseException`s
@@ -44,8 +40,7 @@ except* (TypeError, AttributeError) as e:
 try:
     help()
 except* (KeyboardInterrupt, AttributeError) as e:
-    # TODO: more precise would be `BaseExceptionGroup[KeyboardInterrupt | AttributeError]` --Alex
-    reveal_type(e)  # revealed: BaseExceptionGroup[BaseException]
+    reveal_type(e)  # revealed: BaseExceptionGroup[KeyboardInterrupt | AttributeError]
 ```
 
 ## Invalid `except*` handlers
@@ -54,10 +49,10 @@ except* (KeyboardInterrupt, AttributeError) as e:
 try:
     help()
 except* 3 as e:  # error: [invalid-exception-caught]
-    reveal_type(e)  # revealed: BaseExceptionGroup[BaseException]
+    reveal_type(e)  # revealed: BaseExceptionGroup[Unknown]
 
 try:
     help()
 except* (AttributeError, 42) as e:  # error: [invalid-exception-caught]
-    reveal_type(e)  # revealed: BaseExceptionGroup[BaseException]
+    reveal_type(e)  # revealed: BaseExceptionGroup[AttributeError | Unknown]
 ```

crates/ty_python_semantic/resources/mdtest/function/parameters.md

@@ -25,8 +25,7 @@ def f(a, b: int, c=1, d: int = 2, /, e=3, f: Literal[4] = 4, *args: object, g=5,
     reveal_type(f)  # revealed: Literal[4]
     reveal_type(g)  # revealed: Unknown | Literal[5]
     reveal_type(h)  # revealed: Literal[6]
-    # TODO: should be `tuple[object, ...]`
-    reveal_type(args)  # revealed: tuple[Unknown, ...]
+    reveal_type(args)  # revealed: tuple[object, ...]
     reveal_type(kwargs)  # revealed: dict[str, str]
 ```
 

crates/ty_python_semantic/resources/mdtest/function/return_type.md

@@ -318,7 +318,7 @@ def f(cond: bool) -> str:
     return "hello" if cond else NotImplemented
 
 def f(cond: bool) -> int:
-    # error: [invalid-return-type] "Return type does not match returned value: Expected `int`, found `Literal["hello"]`"
+    # error: [invalid-return-type] "Return type does not match returned value: expected `int`, found `Literal["hello"]`"
     return "hello" if cond else NotImplemented
 ```
 

crates/ty_python_semantic/resources/mdtest/generics/legacy/functions.md

@@ -66,18 +66,68 @@ reveal_type(f("string"))  # revealed: Literal["string"]
 ## Inferring “deep” generic parameter types
 
 The matching up of call arguments and discovery of constraints on typevars can be a recursive
-process for arbitrarily-nested generic types in parameters.
+process for arbitrarily-nested generic classes and protocols in parameters.
+
+TODO: Note that we can currently only infer a specialization for a generic protocol when the
+argument _explicitly_ implements the protocol by listing it as a base class.
 
 ```py
-from typing import TypeVar
+from typing import Protocol, TypeVar
 
 T = TypeVar("T")
 
-def f(x: list[T]) -> T:
+class CanIndex(Protocol[T]):
+    def __getitem__(self, index: int) -> T: ...
+
+class ExplicitlyImplements(CanIndex[T]): ...
+
+def takes_in_list(x: list[T]) -> list[T]:
+    return x
+
+def takes_in_protocol(x: CanIndex[T]) -> T:
     return x[0]
 
-# TODO: revealed: float
-reveal_type(f([1.0, 2.0]))  # revealed: Unknown
+def deep_list(x: list[str]) -> None:
+    reveal_type(takes_in_list(x))  # revealed: list[str]
+    # TODO: revealed: str
+    reveal_type(takes_in_protocol(x))  # revealed: Unknown
+
+def deeper_list(x: list[set[str]]) -> None:
+    reveal_type(takes_in_list(x))  # revealed: list[set[str]]
+    # TODO: revealed: set[str]
+    reveal_type(takes_in_protocol(x))  # revealed: Unknown
+
+def deep_explicit(x: ExplicitlyImplements[str]) -> None:
+    reveal_type(takes_in_protocol(x))  # revealed: str
+
+def deeper_explicit(x: ExplicitlyImplements[set[str]]) -> None:
+    reveal_type(takes_in_protocol(x))  # revealed: set[str]
+
+def takes_in_type(x: type[T]) -> type[T]:
+    return x
+
+reveal_type(takes_in_type(int))  # revealed: @Todo(unsupported type[X] special form)
+```
+
+This also works when passing in arguments that are subclasses of the parameter type.
+
+```py
+class Sub(list[int]): ...
+class GenericSub(list[T]): ...
+
+reveal_type(takes_in_list(Sub()))  # revealed: list[int]
+# TODO: revealed: int
+reveal_type(takes_in_protocol(Sub()))  # revealed: Unknown
+
+reveal_type(takes_in_list(GenericSub[str]()))  # revealed: list[str]
+# TODO: revealed: str
+reveal_type(takes_in_protocol(GenericSub[str]()))  # revealed: Unknown
+
+class ExplicitSub(ExplicitlyImplements[int]): ...
+class ExplicitGenericSub(ExplicitlyImplements[T]): ...
+
+reveal_type(takes_in_protocol(ExplicitSub()))  # revealed: int
+reveal_type(takes_in_protocol(ExplicitGenericSub[str]()))  # revealed: str
 ```
 
 ## Inferring a bound typevar
@@ -144,7 +194,7 @@ def good_return(x: T) -> T:
     return x
 
 def bad_return(x: T) -> T:
-    # error: [invalid-return-type] "Return type does not match returned value: Expected `T`, found `int`"
+    # error: [invalid-return-type] "Return type does not match returned value: expected `T`, found `int`"
     return x + 1
 ```
 
@@ -162,7 +212,7 @@ def different_types(cond: bool, t: T, s: S) -> T:
     if cond:
         return t
     else:
-        # error: [invalid-return-type] "Return type does not match returned value: Expected `T`, found `S`"
+        # error: [invalid-return-type] "Return type does not match returned value: expected `T`, found `S`"
         return s
 
 def same_types(cond: bool, t1: T, t2: T) -> T:

crates/ty_python_semantic/resources/mdtest/generics/pep695/functions.md

@@ -61,14 +61,68 @@ reveal_type(f("string"))  # revealed: Literal["string"]
 ## Inferring “deep” generic parameter types
 
 The matching up of call arguments and discovery of constraints on typevars can be a recursive
-process for arbitrarily-nested generic types in parameters.
+process for arbitrarily-nested generic classes and protocols in parameters.
+
+TODO: Note that we can currently only infer a specialization for a generic protocol when the
+argument _explicitly_ implements the protocol by listing it as a base class.
 
 ```py
-def f[T](x: list[T]) -> T:
+from typing import Protocol, TypeVar
+
+S = TypeVar("S")
+
+class CanIndex(Protocol[S]):
+    def __getitem__(self, index: int) -> S: ...
+
+class ExplicitlyImplements[T](CanIndex[T]): ...
+
+def takes_in_list[T](x: list[T]) -> list[T]:
+    return x
+
+def takes_in_protocol[T](x: CanIndex[T]) -> T:
     return x[0]
 
-# TODO: revealed: float
-reveal_type(f([1.0, 2.0]))  # revealed: Unknown
+def deep_list(x: list[str]) -> None:
+    reveal_type(takes_in_list(x))  # revealed: list[str]
+    # TODO: revealed: str
+    reveal_type(takes_in_protocol(x))  # revealed: Unknown
+
+def deeper_list(x: list[set[str]]) -> None:
+    reveal_type(takes_in_list(x))  # revealed: list[set[str]]
+    # TODO: revealed: set[str]
+    reveal_type(takes_in_protocol(x))  # revealed: Unknown
+
+def deep_explicit(x: ExplicitlyImplements[str]) -> None:
+    reveal_type(takes_in_protocol(x))  # revealed: str
+
+def deeper_explicit(x: ExplicitlyImplements[set[str]]) -> None:
+    reveal_type(takes_in_protocol(x))  # revealed: set[str]
+
+def takes_in_type[T](x: type[T]) -> type[T]:
+    return x
+
+reveal_type(takes_in_type(int))  # revealed: @Todo(unsupported type[X] special form)
+```
+
+This also works when passing in arguments that are subclasses of the parameter type.
+
+```py
+class Sub(list[int]): ...
+class GenericSub[T](list[T]): ...
+
+reveal_type(takes_in_list(Sub()))  # revealed: list[int]
+# TODO: revealed: int
+reveal_type(takes_in_protocol(Sub()))  # revealed: Unknown
+
+reveal_type(takes_in_list(GenericSub[str]()))  # revealed: list[str]
+# TODO: revealed: str
+reveal_type(takes_in_protocol(GenericSub[str]()))  # revealed: Unknown
+
+class ExplicitSub(ExplicitlyImplements[int]): ...
+class ExplicitGenericSub[T](ExplicitlyImplements[T]): ...
+
+reveal_type(takes_in_protocol(ExplicitSub()))  # revealed: int
+reveal_type(takes_in_protocol(ExplicitGenericSub[str]()))  # revealed: str
 ```
 
 ## Inferring a bound typevar
@@ -125,7 +179,7 @@ def good_return[T: int](x: T) -> T:
     return x
 
 def bad_return[T: int](x: T) -> T:
-    # error: [invalid-return-type] "Return type does not match returned value: Expected `T`, found `int`"
+    # error: [invalid-return-type] "Return type does not match returned value: expected `T`, found `int`"
     return x + 1
 ```
 
@@ -138,7 +192,7 @@ def different_types[T, S](cond: bool, t: T, s: S) -> T:
     if cond:
         return t
     else:
-        # error: [invalid-return-type] "Return type does not match returned value: Expected `T`, found `S`"
+        # error: [invalid-return-type] "Return type does not match returned value: expected `T`, found `S`"
         return s
 
 def same_types[T](cond: bool, t1: T, t2: T) -> T:

crates/ty_python_semantic/resources/mdtest/import/cyclic.md

@@ -0,0 +1,108 @@
+## Cyclic imports
+
+### Regression tests
+
+#### Issue 261
+
+See: <https://github.com/astral-sh/ty/issues/261>
+
+`main.py`:
+
+```py
+from foo import bar
+
+reveal_type(bar)  # revealed: <module 'foo.bar'>
+```
+
+`foo/__init__.py`:
+
+```py
+from foo import bar
+
+__all__ = ["bar"]
+```
+
+`foo/bar/__init__.py`:
+
+```py
+# empty
+```
+
+#### Issue 113
+
+See: <https://github.com/astral-sh/ty/issues/113>
+
+`main.py`:
+
+```py
+from pkg.sub import A
+
+# TODO: This should be `<class 'A'>`
+reveal_type(A)  # revealed: Never
+```
+
+`pkg/outer.py`:
+
+```py
+class A: ...
+```
+
+`pkg/sub/__init__.py`:
+
+```py
+from ..outer import *
+from .inner import *
+```
+
+`pkg/sub/inner.py`:
+
+```py
+from pkg.sub import A
+```
+
+### Actual cycle
+
+The following example fails at runtime. Ideally, we would emit a diagnostic here. For now, we only
+make sure that this does not lead to a module resolution cycle.
+
+`main.py`:
+
+```py
+from module import x
+
+reveal_type(x)  # revealed: Unknown
+```
+
+`module.py`:
+
+```py
+# error: [unresolved-import]
+from module import x
+```
+
+### Normal self-referential import
+
+Some modules like `sys` in typeshed import themselves. Here, we make sure that this does not lead to
+cycles or unresolved imports.
+
+`module/__init__.py`:
+
+```py
+import module  # self-referential import
+
+from module.sub import x
+```
+
+`module/sub.py`:
+
+```py
+x: int = 1
+```
+
+`main.py`:
+
+```py
+from module import x
+
+reveal_type(x)  # revealed: int
+```

crates/ty_python_semantic/resources/mdtest/mro.md

@@ -177,6 +177,23 @@ if not isinstance(DoesNotExist, type):
     reveal_type(Foo.__mro__)  # revealed: tuple[<class 'Foo'>, Unknown, <class 'object'>]
 ```
 
+## Inheritance from `type[Any]` and `type[Unknown]`
+
+Inheritance from `type[Any]` and `type[Unknown]` is also permitted, in keeping with the gradual
+guarantee:
+
+```py
+from typing import Any
+from ty_extensions import Unknown, Intersection
+
+def f(x: type[Any], y: Intersection[Unknown, type[Any]]):
+    class Foo(x): ...
+    reveal_type(Foo.__mro__)  # revealed: tuple[<class 'Foo'>, Any, <class 'object'>]
+
+    class Bar(y): ...
+    reveal_type(Bar.__mro__)  # revealed: tuple[<class 'Bar'>, Unknown, <class 'object'>]
+```
+
 ## `__bases__` lists that cause errors at runtime
 
 If the class's `__bases__` cause an exception to be raised at runtime and therefore the class

crates/ty_python_semantic/resources/mdtest/named_tuple.md

@@ -149,3 +149,20 @@ Person = namedtuple("Person", ["id", "name", "age"], defaults=[None])
 alice = Person(1, "Alice", 42)
 bob = Person(2, "Bob")
 ```
+
+## NamedTuple with custom `__getattr__`
+
+This is a regression test for <https://github.com/astral-sh/ty/issues/322>. Make sure that the
+`__getattr__` method does not interfere with the `NamedTuple` behavior.
+
+```py
+from typing import NamedTuple
+
+class Vec2(NamedTuple):
+    x: float = 0.0
+    y: float = 0.0
+
+    def __getattr__(self, attrs: str): ...
+
+Vec2(0.0, 0.0)
+```

crates/ty_python_semantic/resources/mdtest/narrow/hasattr.md

@@ -15,12 +15,24 @@ def f(x: Foo):
     if hasattr(x, "spam"):
         reveal_type(x)  # revealed: Foo & <Protocol with members 'spam'>
         reveal_type(x.spam)  # revealed: object
+    else:
+        reveal_type(x)  # revealed: Foo & ~<Protocol with members 'spam'>
+
+        # TODO: should error and reveal `Unknown`
+        reveal_type(x.spam)  # revealed: @Todo(map_with_boundness: intersections with negative contributions)
 
     if hasattr(x, "not-an-identifier"):
         reveal_type(x)  # revealed: Foo
+    else:
+        reveal_type(x)  # revealed: Foo
 
 def y(x: Bar):
     if hasattr(x, "spam"):
         reveal_type(x)  # revealed: Never
         reveal_type(x.spam)  # revealed: Never
+    else:
+        reveal_type(x)  # revealed: Bar
+
+        # error: [unresolved-attribute]
+        reveal_type(x.spam)  # revealed: Unknown
 ```

crates/ty_python_semantic/resources/mdtest/pep695_type_aliases.md

@@ -68,10 +68,7 @@ y: MyIntOrStr = None
 
 ```py
 type ListOrSet[T] = list[T] | set[T]
-
-# TODO: Should be `tuple[typing.TypeVar | typing.ParamSpec | typing.TypeVarTuple, ...]`,
-# as specified in the `typeshed` stubs.
-reveal_type(ListOrSet.__type_params__)  # revealed: @Todo(full tuple[...] support)
+reveal_type(ListOrSet.__type_params__)  # revealed: tuple[TypeVar | ParamSpec | TypeVarTuple, ...]
 ```
 
 ## `TypeAliasType` properties

crates/ty_python_semantic/resources/mdtest/scopes/moduletype_attrs.md

@@ -8,7 +8,8 @@ is unbound.
 
 ```py
 reveal_type(__name__)  # revealed: str
-reveal_type(__file__)  # revealed: str | None
+# Typeshed says this is str | None, but for a pure-Python on-disk module its always str
+reveal_type(__file__)  # revealed: str
 reveal_type(__loader__)  # revealed: LoaderProtocol | None
 reveal_type(__package__)  # revealed: str | None
 reveal_type(__doc__)  # revealed: str | None
@@ -39,6 +40,39 @@ reveal_type(__dict__)
 reveal_type(__init__)
 ```
 
+## `ModuleType` globals combined with explicit assignments and declarations
+
+A `ModuleType` attribute can be overridden in the global scope with a different type, but it must be
+a type assignable to the declaration on `ModuleType` unless it is accompanied by an explicit
+redeclaration:
+
+`module.py`:
+
+```py
+__file__ = None
+__path__: list[str] = []
+__doc__: int  # error: [invalid-declaration] "Cannot declare type `int` for inferred type `str | None`"
+# error: [invalid-declaration] "Cannot shadow implicit global attribute `__package__` with declaration of type `int`"
+__package__: int = 42
+__spec__ = 42  # error: [invalid-assignment] "Object of type `Literal[42]` is not assignable to `ModuleSpec | None`"
+```
+
+`main.py`:
+
+```py
+import module
+
+reveal_type(module.__file__)  # revealed: Unknown | None
+reveal_type(module.__path__)  # revealed: list[str]
+reveal_type(module.__doc__)  # revealed: Unknown
+reveal_type(module.__spec__)  # revealed: Unknown | ModuleSpec | None
+
+def nested_scope():
+    global __loader__
+    reveal_type(__loader__)  # revealed: LoaderProtocol | None
+    __loader__ = 56  # error: [invalid-assignment] "Object of type `Literal[56]` is not assignable to `LoaderProtocol | None`"
+```
+
 ## Accessed as attributes
 
 `ModuleType` attributes can also be accessed as attributes on module-literal types. The special
@@ -52,6 +86,10 @@ import typing
 reveal_type(typing.__name__)  # revealed: str
 reveal_type(typing.__init__)  # revealed: bound method ModuleType.__init__(name: str, doc: str | None = ellipsis) -> None
 
+# For a stub module, we don't know that `__file__` is a string (at runtime it may be entirely
+# unset, but we follow typeshed here):
+reveal_type(typing.__file__)  # revealed: str | None
+
 # These come from `builtins.object`, not `types.ModuleType`:
 reveal_type(typing.__eq__)  # revealed: bound method ModuleType.__eq__(value: object, /) -> bool
 
@@ -100,16 +138,16 @@ defined as a global, however, a name lookup should union the `ModuleType` type w
 conditionally defined type:
 
 ```py
-__file__ = 42
+__file__ = "foo"
 
 def returns_bool() -> bool:
     return True
 
 if returns_bool():
-    __name__ = 1
+    __name__ = 1  # error: [invalid-assignment] "Object of type `Literal[1]` is not assignable to `str`"
 
-reveal_type(__file__)  # revealed: Literal[42]
-reveal_type(__name__)  # revealed: Literal[1] | str
+reveal_type(__file__)  # revealed: Literal["foo"]
+reveal_type(__name__)  # revealed: str
 ```
 
 ## Conditionally global or `ModuleType` attribute, with annotation
@@ -117,12 +155,14 @@ reveal_type(__name__)  # revealed: Literal[1] | str
 The same is true if the name is annotated:
 
 ```py
+# error: [invalid-declaration] "Cannot shadow implicit global attribute `__file__` with declaration of type `int`"
 __file__: int = 42
 
 def returns_bool() -> bool:
     return True
 
 if returns_bool():
+    # error: [invalid-declaration] "Cannot shadow implicit global attribute `__name__` with declaration of type `int`"
     __name__: int = 1
 
 reveal_type(__file__)  # revealed: Literal[42]

crates/ty_python_semantic/resources/mdtest/snapshots/assert_never.md_-_`assert_never`_-_Basic_functionality_(78e7b52096b8d36c).snap

@@ -0,0 +1,189 @@
+---
+source: crates/ty_test/src/lib.rs
+expression: snapshot
+---
+---
+mdtest name: assert_never.md - `assert_never` - Basic functionality
+mdtest path: crates/ty_python_semantic/resources/mdtest/directives/assert_never.md
+---
+
+# Python source files
+
+## mdtest_snippet.py
+
+```
+ 1 | from typing_extensions import assert_never, Never, Any
+ 2 | from ty_extensions import Unknown
+ 3 | 
+ 4 | def _(never: Never, any_: Any, unknown: Unknown, flag: bool):
+ 5 |     assert_never(never)  # fine
+ 6 | 
+ 7 |     assert_never(0)  # error: [type-assertion-failure]
+ 8 |     assert_never("")  # error: [type-assertion-failure]
+ 9 |     assert_never(None)  # error: [type-assertion-failure]
+10 |     assert_never([])  # error: [type-assertion-failure]
+11 |     assert_never({})  # error: [type-assertion-failure]
+12 |     assert_never(())  # error: [type-assertion-failure]
+13 |     assert_never(1 if flag else never)  # error: [type-assertion-failure]
+14 | 
+15 |     assert_never(any_)  # error: [type-assertion-failure]
+16 |     assert_never(unknown)  # error: [type-assertion-failure]
+```
+
+# Diagnostics
+
+```
+error[type-assertion-failure]: Argument does not have asserted type `Never`
+ --> src/mdtest_snippet.py:7:5
+  |
+5 |     assert_never(never)  # fine
+6 |
+7 |     assert_never(0)  # error: [type-assertion-failure]
+  |     ^^^^^^^^^^^^^-^
+  |                  |
+  |                  Inferred type of argument is `Literal[0]`
+8 |     assert_never("")  # error: [type-assertion-failure]
+9 |     assert_never(None)  # error: [type-assertion-failure]
+  |
+info: `Never` and `Literal[0]` are not equivalent types
+info: rule `type-assertion-failure` is enabled by default
+
+```
+
+```
+error[type-assertion-failure]: Argument does not have asserted type `Never`
+  --> src/mdtest_snippet.py:8:5
+   |
+ 7 |     assert_never(0)  # error: [type-assertion-failure]
+ 8 |     assert_never("")  # error: [type-assertion-failure]
+   |     ^^^^^^^^^^^^^--^
+   |                  |
+   |                  Inferred type of argument is `Literal[""]`
+ 9 |     assert_never(None)  # error: [type-assertion-failure]
+10 |     assert_never([])  # error: [type-assertion-failure]
+   |
+info: `Never` and `Literal[""]` are not equivalent types
+info: rule `type-assertion-failure` is enabled by default
+
+```
+
+```
+error[type-assertion-failure]: Argument does not have asserted type `Never`
+  --> src/mdtest_snippet.py:9:5
+   |
+ 7 |     assert_never(0)  # error: [type-assertion-failure]
+ 8 |     assert_never("")  # error: [type-assertion-failure]
+ 9 |     assert_never(None)  # error: [type-assertion-failure]
+   |     ^^^^^^^^^^^^^----^
+   |                  |
+   |                  Inferred type of argument is `None`
+10 |     assert_never([])  # error: [type-assertion-failure]
+11 |     assert_never({})  # error: [type-assertion-failure]
+   |
+info: `Never` and `None` are not equivalent types
+info: rule `type-assertion-failure` is enabled by default
+
+```
+
+```
+error[type-assertion-failure]: Argument does not have asserted type `Never`
+  --> src/mdtest_snippet.py:10:5
+   |
+ 8 |     assert_never("")  # error: [type-assertion-failure]
+ 9 |     assert_never(None)  # error: [type-assertion-failure]
+10 |     assert_never([])  # error: [type-assertion-failure]
+   |     ^^^^^^^^^^^^^--^
+   |                  |
+   |                  Inferred type of argument is `list[Unknown]`
+11 |     assert_never({})  # error: [type-assertion-failure]
+12 |     assert_never(())  # error: [type-assertion-failure]
+   |
+info: `Never` and `list[Unknown]` are not equivalent types
+info: rule `type-assertion-failure` is enabled by default
+
+```
+
+```
+error[type-assertion-failure]: Argument does not have asserted type `Never`
+  --> src/mdtest_snippet.py:11:5
+   |
+ 9 |     assert_never(None)  # error: [type-assertion-failure]
+10 |     assert_never([])  # error: [type-assertion-failure]
+11 |     assert_never({})  # error: [type-assertion-failure]
+   |     ^^^^^^^^^^^^^--^
+   |                  |
+   |                  Inferred type of argument is `dict[Unknown, Unknown]`
+12 |     assert_never(())  # error: [type-assertion-failure]
+13 |     assert_never(1 if flag else never)  # error: [type-assertion-failure]
+   |
+info: `Never` and `dict[Unknown, Unknown]` are not equivalent types
+info: rule `type-assertion-failure` is enabled by default
+
+```
+
+```
+error[type-assertion-failure]: Argument does not have asserted type `Never`
+  --> src/mdtest_snippet.py:12:5
+   |
+10 |     assert_never([])  # error: [type-assertion-failure]
+11 |     assert_never({})  # error: [type-assertion-failure]
+12 |     assert_never(())  # error: [type-assertion-failure]
+   |     ^^^^^^^^^^^^^--^
+   |                  |
+   |                  Inferred type of argument is `tuple[()]`
+13 |     assert_never(1 if flag else never)  # error: [type-assertion-failure]
+   |
+info: `Never` and `tuple[()]` are not equivalent types
+info: rule `type-assertion-failure` is enabled by default
+
+```
+
+```
+error[type-assertion-failure]: Argument does not have asserted type `Never`
+  --> src/mdtest_snippet.py:13:5
+   |
+11 |     assert_never({})  # error: [type-assertion-failure]
+12 |     assert_never(())  # error: [type-assertion-failure]
+13 |     assert_never(1 if flag else never)  # error: [type-assertion-failure]
+   |     ^^^^^^^^^^^^^--------------------^
+   |                  |
+   |                  Inferred type of argument is `Literal[1]`
+14 |
+15 |     assert_never(any_)  # error: [type-assertion-failure]
+   |
+info: `Never` and `Literal[1]` are not equivalent types
+info: rule `type-assertion-failure` is enabled by default
+
+```
+
+```
+error[type-assertion-failure]: Argument does not have asserted type `Never`
+  --> src/mdtest_snippet.py:15:5
+   |
+13 |     assert_never(1 if flag else never)  # error: [type-assertion-failure]
+14 |
+15 |     assert_never(any_)  # error: [type-assertion-failure]
+   |     ^^^^^^^^^^^^^----^
+   |                  |
+   |                  Inferred type of argument is `Any`
+16 |     assert_never(unknown)  # error: [type-assertion-failure]
+   |
+info: `Never` and `Any` are not equivalent types
+info: rule `type-assertion-failure` is enabled by default
+
+```
+
+```
+error[type-assertion-failure]: Argument does not have asserted type `Never`
+  --> src/mdtest_snippet.py:16:5
+   |
+15 |     assert_never(any_)  # error: [type-assertion-failure]
+16 |     assert_never(unknown)  # error: [type-assertion-failure]
+   |     ^^^^^^^^^^^^^-------^
+   |                  |
+   |                  Inferred type of argument is `Unknown`
+   |
+info: `Never` and `Unknown` are not equivalent types
+info: rule `type-assertion-failure` is enabled by default
+
+```

crates/ty_python_semantic/resources/mdtest/snapshots/assert_type.md_-_`assert_type`_-_Basic_(c507788da2659ec9).snap

@@ -0,0 +1,38 @@
+---
+source: crates/ty_test/src/lib.rs
+expression: snapshot
+---
+---
+mdtest name: assert_type.md - `assert_type` - Basic
+mdtest path: crates/ty_python_semantic/resources/mdtest/directives/assert_type.md
+---
+
+# Python source files
+
+## mdtest_snippet.py
+
+```
+1 | from typing_extensions import assert_type
+2 | 
+3 | def _(x: int):
+4 |     assert_type(x, int)  # fine
+5 |     assert_type(x, str)  # error: [type-assertion-failure]
+```
+
+# Diagnostics
+
+```
+error[type-assertion-failure]: Argument does not have asserted type `str`
+ --> src/mdtest_snippet.py:5:5
+  |
+3 | def _(x: int):
+4 |     assert_type(x, int)  # fine
+5 |     assert_type(x, str)  # error: [type-assertion-failure]
+  |     ^^^^^^^^^^^^-^^^^^^
+  |                 |
+  |                 Inferred type of argument is `int`
+  |
+info: `str` and `int` are not equivalent types
+info: rule `type-assertion-failure` is enabled by default
+
+```