Update crates/red_knot_python_semantic/src/types/infer.rs

Co-authored-by: Carl Meyer <[email protected]>

crates/red_knot_python_semantic/src/types/infer.rs

@@ -1127,7 +1127,7 @@ impl<'db> TypeInferenceBuilder<'db> {
             let inferred_ty = if let Some(default_ty) = default_ty {
                 if default_ty.is_assignable_to(self.db, declared_ty) {
                     UnionType::from_elements(self.db, [declared_ty, default_ty])
-                } else if default
+                } else if self.file.is_stub() && default
                     .as_ref()
                     .is_some_and(|d| d.is_ellipsis_literal_expr())
                 {