fix type errors in checker.py discovered by self-check

Author: Kunal Sali

mypy/checker.py

@@ -6249,15 +6249,16 @@ def conditional_callable_type_map(
         if not current_type:
             return {}, {}
 
-        if isinstance(get_proper_type(current_type), AnyType):
+        proper_type = get_proper_type(current_type)
+        if isinstance(proper_type, AnyType):
             # Narrow Any to a generic callable type to satisfy no-any-return in strict mode.
             return {
                 expr: CallableType(
-                    [AnyType(TypeOfAny.from_another_any, source_any=current_type),
-                     AnyType(TypeOfAny.from_another_any, source_any=current_type)],
+                    [AnyType(TypeOfAny.from_another_any, source_any=proper_type),
+                     AnyType(TypeOfAny.from_another_any, source_any=proper_type)],
                     [nodes.ARG_STAR, nodes.ARG_STAR2],
                     [None, None],
-                    ret_type=AnyType(TypeOfAny.from_another_any, source_any=current_type),
+                    ret_type=AnyType(TypeOfAny.from_another_any, source_any=proper_type),
                     fallback=self.named_type("builtins.function"),
                     is_ellipsis_args=True,
                 )