Do not annotate variables as type guards

A5rocks · A5rocks · commit 3f068f5246b9 · 2021-06-19T12:11:24.000+09:00
diff --git a/mypy/checker.py b/mypy/checker.py
@@ -4102,7 +4102,7 @@ def find_isinstance_check_helper(self, node: Expression) -> Tuple[TypeMap, TypeM
                         self.fail("Type guard requires positional argument", node)
                         return {}, {}
                     if literal(expr) == LITERAL_TYPE:
-                        return {expr: TypeGuardType(node.callee.type_guard)}, {}
+                        return {expr: node.callee.type_guard}, {}
         elif isinstance(node, ComparisonExpr):
             # Step 1: Obtain the types of each operand and whether or not we can
             # narrow their types. (For example, we shouldn't try narrowing the
