Language/Types/Function_Types/subtype_no_args_t05.dart

// Copyright (c) 2011, 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.

/// @assertion A function type (T1,...Tk,[Tk+1,...,Tn+m]) -> T is a subtype of
/// the function type (S1,...,Sk+j,[Sk+j+1,...,Sn]) -> S, if all of the following
/// conditions are met:
/// 1. Either
///    • S is void, or
///    • T <=> S.
/// 2. ∀i ∈ 1..n, Ti ⇐⇒ Si.
/// @description Checks that function type t1 is not a subtype of function type
/// t2 if return types of t1 and t2 are not mutually assignable.
/// @author iefremov

import "../../../Utils/expect.dart";

class A {}
class B {}

typedef int t1();
typedef A t2();
typedef List<A> t3();
typedef t1 t4();

double f1() => 3.14;
bool f2() => false;
A f3() => new A();
List<int> f4() => [3, 1, 4];
t2? f5() {}
t3? f6() {}

main() {
  Expect.isFalse(f1 is t1);
  Expect.isFalse(f2 is t1);
  Expect.isFalse(f3 is t1);
  Expect.isFalse(f4 is t1);
  Expect.isFalse(f5 is t1);
  Expect.isFalse(f5 is t1);

  Expect.isFalse(f1 is t2);
  Expect.isFalse(f2 is t2);
  Expect.isFalse(f4 is t2);
  Expect.isFalse(f5 is t2);
  Expect.isFalse(f6 is t2);

  Expect.isFalse(f1 is t3);
  Expect.isFalse(f2 is t3);
  Expect.isFalse(f3 is t3);
  Expect.isFalse(f4 is t3);
  Expect.isFalse(f5 is t3);
  Expect.isFalse(f6 is t3);

  Expect.isFalse(f1 is t4);
  Expect.isFalse(f2 is t4);
  Expect.isFalse(f3 is t4);
  Expect.isFalse(f4 is t4);
  Expect.isFalse(f5 is t4);
  Expect.isFalse(f6 is t4);
}