Ignore N815 for TypedDict fields (#4066)

crates/ruff/resources/test/fixtures/pep8_naming/N815.py

@@ -13,3 +13,11 @@ class C:
     myObj2 = namedtuple("MyObj2", ["a", "b"])
     Employee = NamedTuple('Employee', [('name', str), ('id', int)])
     Point2D = TypedDict('Point2D', {'in': int, 'x-y': int})
+
+
+class D(TypedDict):
+    lower: int
+    CONSTANT: str
+    mixedCase: bool
+    _mixedCase: list
+    mixed_Case: set

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

@@ -4456,8 +4456,14 @@ impl<'a> Checker<'a> {
             .rules
             .enabled(Rule::MixedCaseVariableInClassScope)
         {
-            if matches!(self.ctx.scope().kind, ScopeKind::Class(..)) {
-                pep8_naming::rules::mixed_case_variable_in_class_scope(self, expr, parent, id);
+            if let ScopeKind::Class(class) = &self.ctx.scope().kind {
+                pep8_naming::rules::mixed_case_variable_in_class_scope(
+                    self,
+                    expr,
+                    parent,
+                    id,
+                    class.bases,
+                );
             }
         }
 

crates/ruff/src/rules/pep8_naming/helpers.rs

@@ -1,5 +1,5 @@
 use itertools::Itertools;
-use rustpython_parser::ast::{ExprKind, Stmt, StmtKind};
+use rustpython_parser::ast::{Expr, ExprKind, Stmt, StmtKind};
 
 use ruff_python_stdlib::str::{is_lower, is_upper};
 
@@ -70,6 +70,12 @@ pub fn is_type_var_assignment(checker: &Checker, stmt: &Stmt) -> bool {
         })
 }
 
+pub fn is_typeddict(checker: &Checker, bases: &[Expr]) -> bool {
+    bases
+        .iter()
+        .any(|base| checker.ctx.match_typing_expr(base, "TypedDict"))
+}
+
 #[cfg(test)]
 mod tests {
     use super::{is_acronym, is_camelcase, is_mixed_case};

crates/ruff/src/rules/pep8_naming/rules/mixed_case_variable_in_class_scope.rs

@@ -26,6 +26,7 @@ pub fn mixed_case_variable_in_class_scope(
     expr: &Expr,
     stmt: &Stmt,
     name: &str,
+    bases: &[Expr],
 ) {
     if checker
         .settings
@@ -36,7 +37,10 @@ pub fn mixed_case_variable_in_class_scope(
     {
         return;
     }
-    if helpers::is_mixed_case(name) && !helpers::is_namedtuple_assignment(checker, stmt) {
+    if helpers::is_mixed_case(name)
+        && !helpers::is_namedtuple_assignment(checker, stmt)
+        && !helpers::is_typeddict(checker, bases)
+    {
         checker.diagnostics.push(Diagnostic::new(
             MixedCaseVariableInClassScope {
                 name: name.to_string(),