Add more tests; move into redefines

crates/ruff_linter/resources/test/fixtures/pyflakes/F811_30.py

@@ -11,3 +11,27 @@ def foo(self) -> None:
 
     def bar(self) -> None:
         """Bar."""
+
+
+class B:
+    """B."""
+    def baz(self) -> None:
+        """Baz."""
+
+    baz = 1
+
+
+class C:
+    """C."""
+    def foo(self) -> None:
+        """Foo."""
+
+    bar = (foo := 1)
+
+
+class D:
+    """D."""
+    foo = 1
+    foo = 2
+    bar = (foo := 3)
+    bar = (foo := 4)

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

@@ -227,13 +227,6 @@ pub(crate) fn deferred_scopes(checker: &mut Checker) {
                             continue;
                         };
 
-                        // Ignore non-import redefinitions
-                        if matches!(shadowed.kind, BindingKind::Assignment)
-                            && matches!(binding.kind, BindingKind::Assignment)
-                        {
-                            continue;
-                        }
-
                         // If this is an overloaded function, abort.
                         if shadowed.kind.is_function_definition() {
                             if checker

crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__F811_F811_30.py.snap

@@ -10,3 +10,21 @@ F811_30.py:12:9: F811 Redefinition of unused `bar` from line 10
 13 |         """Bar."""
    |
    = help: Remove definition: `bar`
+
+F811_30.py:21:5: F811 Redefinition of unused `baz` from line 18
+   |
+19 |         """Baz."""
+20 | 
+21 |     baz = 1
+   |     ^^^ F811
+   |
+   = help: Remove definition: `baz`
+
+F811_30.py:29:12: F811 Redefinition of unused `foo` from line 26
+   |
+27 |         """Foo."""
+28 | 
+29 |     bar = (foo := 1)
+   |            ^^^ F811
+   |
+   = help: Remove definition: `foo`

crates/ruff_python_semantic/src/binding.rs

@@ -177,6 +177,19 @@ impl<'a> Binding<'a> {
             | BindingKind::Builtin => {
                 return false;
             }
+            // Assignment-assignment bindings are not considered redefinitions, as in:
+            // ```python
+            // x = 1
+            // x = 2
+            // ```
+            BindingKind::Assignment | BindingKind::NamedExprAssignment => {
+                if matches!(
+                    existing.kind,
+                    BindingKind::Assignment | BindingKind::NamedExprAssignment
+                ) {
+                    return false;
+                }
+            }
             _ => {}
         }
         // Otherwise, the shadowed binding must be a class definition, function definition,
@@ -188,6 +201,7 @@ impl<'a> Binding<'a> {
                 | BindingKind::Import(_)
                 | BindingKind::FromImport(_)
                 | BindingKind::Assignment
+                | BindingKind::NamedExprAssignment
         )
     }