diff --git a/mypy/checker.py b/mypy/checker.py
index 237f1cc2f9ea..0e42b0bbcf4c 100644
--- a/mypy/checker.py
+++ b/mypy/checker.py
@@ -4003,6 +4003,8 @@ def find_isinstance_check_helper(self, node: Expression) -> Tuple[TypeMap, TypeM
                     vartype = type_map[expr]
                     return self.conditional_callable_type_map(expr, vartype)
             else:
+                # if isinstance(node.callee, RefExpr) and node.callee.node is None:
+                #     node.callee.node = self.expr_checker.accept(node.callee)
                 if (isinstance(node.callee, RefExpr)
                         and isinstance(node.callee.node, SYMBOL_FUNCBASE_TYPES)
                         and isinstance(node.callee.node.type, CallableType)