Perf improvement

Author: ilevkivskyi

mypy/subtypes.py

@@ -2142,15 +2142,15 @@ def is_erased_instance(t: Instance) -> bool:
     """Is this an instance where all args are Any types?"""
     if not t.args:
         return False
-    for arg in map(get_proper_type, t.args):
+    for arg in t.args:
         if isinstance(arg, UnpackType):
             unpacked = get_proper_type(arg.type)
             if not isinstance(unpacked, Instance):
                 return False
             assert unpacked.type.fullname == "builtins.tuple"
             if not isinstance(get_proper_type(unpacked.args[0]), AnyType):
                 return False
-        elif not isinstance(arg, AnyType):
+        elif not isinstance(get_proper_type(arg), AnyType):
             return False
     else:
         return True