partially revert #2812

Author: elazarg

mypy/checkexpr.py

@@ -1454,9 +1454,6 @@ def visit_index_expr_helper(self, e: IndexExpr) -> Type:
                 return AnyType()
         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().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)
             e.method_type = method_type
@@ -1515,16 +1512,6 @@ def visit_typeddict_index_expr(self, td_type: TypedDictType, index: Expression)
             return AnyType()
         return item_type
 
-    def visit_enum_index_expr(self, enum_type: TypeInfo, index: Expression,
-                              context: Context) -> Type:
-        string_type = self.named_type('builtins.str')  # type: Type
-        if self.chk.options.python_version[0] < 3:
-            string_type = UnionType.make_union([string_type,
-                                                self.named_type('builtins.unicode')])
-        self.chk.check_subtype(self.accept(index), string_type, context,
-                               "Enum index should be a string", "actual index type")
-        return Instance(enum_type, [])
-
     def visit_cast_expr(self, expr: CastExpr) -> Type:
         """Type check a cast expression."""
         source_type = self.accept(expr.expr, type_context=AnyType())