Respond to review by @ilevkivskyi

Author: Guido van Rossum

mypy/checkexpr.py

@@ -1440,7 +1440,7 @@ def visit_index_expr_helper(self, e: IndexExpr) -> Type:
         elif isinstance(left_type, TypedDictType):
             return self.visit_typeddict_index_expr(left_type, e.index)
         elif (isinstance(left_type, CallableType)
-              and left_type.is_type_obj() and left_type.type_object()):
+              and left_type.is_type_obj() and left_type.type_object().is_enum):
             return self.visit_enum_index_expr(left_type.type_object(), e.index, e)
         else:
             result, method_type = self.check_op('__getitem__', left_type, e.index, e)

test-data/unit/pythoneval-enum.test

@@ -149,3 +149,11 @@ s = None  # type: str
 reveal_type(E[s])
 [out]
 _program.py:5: error: Revealed type is '_testEnumIndex.E'
+
+[case testEnumIndexError]
+from enum import IntEnum
+class E(IntEnum):
+    a = 1
+E[1]
+[out]
+_program.py:4: error: Enum index should be a string (actual index type "int")