Ignore certain flake8-pyi errors within function bodies (#4029)

Author: charliermarsh

crates/ruff/resources/test/fixtures/flake8_pyi/PYI001.py

@@ -11,3 +11,7 @@
 _TTuple = TypeVarTuple("_TTuple")  # OK
 
 _P = ParamSpec("_P")  # OK
+
+
+def f():
+    T = TypeVar("T")  # OK

crates/ruff/resources/test/fixtures/flake8_pyi/PYI001.pyi

@@ -11,3 +11,6 @@ _T = TypeVar("_T")  # OK
 _TTuple = TypeVarTuple("_TTuple")  # OK
 
 _P = ParamSpec("_P")  # OK
+
+def f():
+    T = TypeVar("T")  # OK

crates/ruff/resources/test/fixtures/flake8_pyi/PYI015.py

@@ -46,3 +46,7 @@
 field23 = "foo" + "bar"  # Y015 Only simple default values are allowed for assignments
 field24 = b"foo" + b"bar"  # Y015 Only simple default values are allowed for assignments
 field25 = 5 * 5  # Y015 Only simple default values are allowed for assignments
+
+# We shouldn't emit Y015 within functions
+def f():
+  field26: list[int] = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]

crates/ruff/resources/test/fixtures/flake8_pyi/PYI015.pyi

@@ -53,3 +53,7 @@ field229: dict[int, int] = {1: 2, **{3: 4}}  # Y015 Only simple default values a
 field23 = "foo" + "bar"  # Y015 Only simple default values are allowed for assignments
 field24 = b"foo" + b"bar"  # Y015 Only simple default values are allowed for assignments
 field25 = 5 * 5  # Y015 Only simple default values are allowed for assignments
+
+# We shouldn't emit Y015 within functions
+def f():
+  field26: list[int] = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]

crates/ruff/src/checkers/ast/mod.rs

@@ -1791,12 +1791,6 @@ where
                     }
                 }
 
-                if self.is_stub {
-                    if self.settings.rules.enabled(Rule::UnprefixedTypeParam) {
-                        flake8_pyi::rules::prefix_type_params(self, value, targets);
-                    }
-                }
-
                 if self.settings.rules.enabled(Rule::GlobalStatement) {
                     for target in targets.iter() {
                         if let ExprKind::Name { id, .. } = &target.node {
@@ -1837,8 +1831,20 @@ where
                 }
 
                 if self.is_stub {
-                    if self.settings.rules.enabled(Rule::AssignmentDefaultInStub) {
-                        flake8_pyi::rules::assignment_default_in_stub(self, value, None);
+                    if self
+                        .settings
+                        .rules
+                        .any_enabled(&[Rule::UnprefixedTypeParam, Rule::AssignmentDefaultInStub])
+                    {
+                        // Ignore assignments in function bodies; those are covered by other rules.
+                        if !self.ctx.scopes().any(|scope| scope.kind.is_function()) {
+                            if self.settings.rules.enabled(Rule::UnprefixedTypeParam) {
+                                flake8_pyi::rules::prefix_type_params(self, value, targets);
+                            }
+                            if self.settings.rules.enabled(Rule::AssignmentDefaultInStub) {
+                                flake8_pyi::rules::assignment_default_in_stub(self, value, None);
+                            }
+                        }
                     }
                 }
             }
@@ -1874,11 +1880,14 @@ where
                 if self.is_stub {
                     if let Some(value) = value {
                         if self.settings.rules.enabled(Rule::AssignmentDefaultInStub) {
-                            flake8_pyi::rules::assignment_default_in_stub(
-                                self,
-                                value,
-                                Some(annotation),
-                            );
+                            // Ignore assignments in function bodies; those are covered by other rules.
+                            if !self.ctx.scopes().any(|scope| scope.kind.is_function()) {
+                                flake8_pyi::rules::assignment_default_in_stub(
+                                    self,
+                                    value,
+                                    Some(annotation),
+                                );
+                            }
                         }
                     }
                 }

crates/ruff/src/rules/flake8_pyi/snapshots/ruff__rules__flake8_pyi__tests__PYI015_PYI015.pyi.snap

@@ -187,6 +187,7 @@ PYI015.pyi:53:11: PYI015 [*] Only simple default values allowed for assignments
    53 |+field23 = ...  # Y015 Only simple default values are allowed for assignments
 54 54 | field24 = b"foo" + b"bar"  # Y015 Only simple default values are allowed for assignments
 55 55 | field25 = 5 * 5  # Y015 Only simple default values are allowed for assignments
+56 56 | 
 
 PYI015.pyi:54:11: PYI015 [*] Only simple default values allowed for assignments
    |
@@ -205,13 +206,17 @@ PYI015.pyi:54:11: PYI015 [*] Only simple default values allowed for assignments
 54    |-field24 = b"foo" + b"bar"  # Y015 Only simple default values are allowed for assignments
    54 |+field24 = ...  # Y015 Only simple default values are allowed for assignments
 55 55 | field25 = 5 * 5  # Y015 Only simple default values are allowed for assignments
+56 56 | 
+57 57 | # We shouldn't emit Y015 within functions
 
 PYI015.pyi:55:11: PYI015 [*] Only simple default values allowed for assignments
    |
 55 | field23 = "foo" + "bar"  # Y015 Only simple default values are allowed for assignments
 56 | field24 = b"foo" + b"bar"  # Y015 Only simple default values are allowed for assignments
 57 | field25 = 5 * 5  # Y015 Only simple default values are allowed for assignments
    |           ^^^^^ PYI015
+58 | 
+59 | # We shouldn't emit Y015 within functions
    |
    = help: Replace default value with `...`
 
@@ -221,5 +226,8 @@ PYI015.pyi:55:11: PYI015 [*] Only simple default values allowed for assignments
 54 54 | field24 = b"foo" + b"bar"  # Y015 Only simple default values are allowed for assignments
 55    |-field25 = 5 * 5  # Y015 Only simple default values are allowed for assignments
    55 |+field25 = ...  # Y015 Only simple default values are allowed for assignments
+56 56 | 
+57 57 | # We shouldn't emit Y015 within functions
+58 58 | def f():
 
 

crates/ruff_python_semantic/src/scope.rs

@@ -131,7 +131,7 @@ impl From<ScopeId> for usize {
     }
 }
 
-#[derive(Debug)]
+#[derive(Debug, is_macro::Is)]
 pub enum ScopeKind<'a> {
     Class(ClassDef<'a>),
     Function(FunctionDef<'a>),