// Copyright (c) 2017, the Dart project authors. Please see the AUTHORS file // for details. All rights reserved. Use of this source code is governed by a // BSD-style license that can be found in the LICENSE file. class A {} class B extends A {} void main() { A a = new B(); B Function(A) f = (A a) => a; // ^ // [analyzer] COMPILE_TIME_ERROR.RETURN_OF_INVALID_TYPE_FROM_CLOSURE // [cfe] A value of type 'A' can't be returned from a function with return type 'B'. }