[pylint] Redefined outer names (PLW0621)

crates/ruff_linter/resources/test/fixtures/pylint/redefined_outer_name.py

@@ -0,0 +1,158 @@
+from __future__ import annotations
+
+import pytest
+
+
+@pytest.fixture
+def f(): ...
+
+@pytest.yield_fixture
+def yf(): ...
+
+
+### Errors
+
+global_a = 1
+
+def outer_1(a):
+    def inner_1(a): ...
+
+
+def outer_2():
+    a = 1
+    def inner_2(a): ...
+
+
+def outer_3():
+    def inner_3(a): ...
+    a = 1
+
+
+def outer_4():
+    def inner_4(outer_4): ...
+
+
+def outer_5(global_a): ...
+
+
+def outer_6():
+    def inner_6(global_a): ...
+
+
+def outer_7():
+    def inner_7(f): ...
+
+
+def outer_8():
+    def inner_8(yf): ...
+
+
+def outer_9(outer_100):
+    ...
+
+
+def outer_10():
+    def inner_10(outer_100): ...
+
+
+class Outer11[T]:
+    def inner_11(self, T): ...
+
+
+def outer_12():
+    a = 0
+    inner_12 = lambda a: a + 1
+
+
+def outer_13():
+    inner_13 = lambda a: lambda a, b: a + b - 1
+
+
+def outer_14():
+    inner_14 = (lambda a, b: a - b / 2 for a, b in [])
+
+
+def outer_15():
+    try:
+        ...
+    except RuntimeError as e:
+        def inner_15(e): ...
+
+
+def outer_16():
+    try:
+        ...
+    except RuntimeError as e:
+        inner_16 = lambda e: ...
+
+
+### No errors
+
+def outer_100(): ...
+
+
+def outer_101(f): ...
+
+
+def outer_102(yf): ...
+
+
+def outer_103():
+    outer_103 = 0
+
+
+def outer_104():
+    def inner_104[outer_104](): ...
+
+
+class Outer105:
+    a = 1
+    def inner_105(self, a): ...
+
+
+class Outer106:
+    def inner_105(self, a): ...
+    a = 1
+
+
+class Outer107:
+    def inner_105(self, a): ...
+    def a(self): ...
+
+
+class Outer108:
+    _ = lambda a: a + 1
+    a = 0
+
+
+class Outer109:
+    a = 0
+    inner_109 = [lambda a: a @ 3 for _ in [1]]
+
+
+def outer_110(annotations): ...
+
+
+def outer_111():
+    _a = 0
+
+    def inner_111(_a): ...
+
+
+def outer_112():
+    inner_112 = lambda _a: ...
+    _a = 0
+
+
+class Outer113:
+    try:
+        ...
+    except RuntimeError as e:
+        def inner_113(e): ...
+
+
+class Outer114:
+    try:
+        ...
+    except RuntimeError as e:
+        inner_114 = lambda e: ...

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

@@ -25,6 +25,7 @@ pub(crate) fn bindings(checker: &Checker) {
         Rule::ForLoopWrites,
         Rule::CustomTypeVarForSelf,
         Rule::PrivateTypeParameter,
+        Rule::RedefinedOuterName,
     ]) {
         return;
     }
@@ -129,5 +130,10 @@ pub(crate) fn bindings(checker: &Checker) {
                 checker.report_diagnostic(diagnostic);
             }
         }
+        if checker.enabled(Rule::RedefinedOuterName) {
+            if let Some(diagnostic) = pylint::rules::redefined_outer_name(checker, binding) {
+                checker.report_diagnostic(diagnostic);
+            }
+        }
     }
 }

crates/ruff_linter/src/codes.rs

@@ -285,6 +285,7 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<(RuleGroup, Rule)> {
         (Pylint, "W0602") => (RuleGroup::Stable, rules::pylint::rules::GlobalVariableNotAssigned),
         (Pylint, "W0603") => (RuleGroup::Stable, rules::pylint::rules::GlobalStatement),
         (Pylint, "W0604") => (RuleGroup::Stable, rules::pylint::rules::GlobalAtModuleLevel),
+        (Pylint, "W0621") => (RuleGroup::Preview, rules::pylint::rules::RedefinedOuterName),
         (Pylint, "W0642") => (RuleGroup::Stable, rules::pylint::rules::SelfOrClsAssignment),
         (Pylint, "W0711") => (RuleGroup::Stable, rules::pylint::rules::BinaryOpException),
         (Pylint, "W1501") => (RuleGroup::Stable, rules::pylint::rules::BadOpenMode),

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

@@ -654,7 +654,7 @@ impl<'a> Visitor<'a> for SkipFunctionsVisitor<'a> {
     }
 }
 
-fn fixture_decorator<'a>(
+pub(crate) fn fixture_decorator<'a>(
     decorators: &'a [Decorator],
     semantic: &SemanticModel,
 ) -> Option<&'a Decorator> {

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

@@ -442,6 +442,7 @@ mod tests {
     )]
     #[test_case(Rule::InvalidEnvvarDefault, Path::new("invalid_envvar_default.py"))]
     #[test_case(Rule::BadStrStripCall, Path::new("bad_str_strip_call.py"))]
+    #[test_case(Rule::RedefinedOuterName, Path::new("redefined_outer_name.py"))]
     fn preview_rules(rule_code: Rule, path: &Path) -> Result<()> {
         let snapshot = format!(
             "preview__{}_{}",

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

@@ -63,6 +63,7 @@ pub(crate) use property_with_parameters::*;
 pub(crate) use redeclared_assigned_name::*;
 pub(crate) use redefined_argument_from_local::*;
 pub(crate) use redefined_loop_name::*;
+pub(crate) use redefined_outer_name::*;
 pub(crate) use redefined_slots_in_subclass::*;
 pub(crate) use repeated_equality_comparison::*;
 pub(crate) use repeated_isinstance_calls::*;
@@ -172,6 +173,7 @@ mod property_with_parameters;
 mod redeclared_assigned_name;
 mod redefined_argument_from_local;
 mod redefined_loop_name;
+mod redefined_outer_name;
 mod redefined_slots_in_subclass;
 mod repeated_equality_comparison;
 mod repeated_isinstance_calls;