Language/Generics/typedef_A05_t04.dart

// Copyright (c) 2019, 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 generic type alias is a declaration [D] of one of the following
/// forms:
///   S0 Function(T1, . . . , Tn, [Tn+1, . . . , Tn+k])
///   S0 Function(T1, . . . , Tn, {Tn+1 xn+1, . . . , Tn+k xn+k})
///   ...
/// [D] introduces a mapping from actual type argument lists to types.
/// @description Checks that [D] maps argument list to correct types
/// @Issue 41939, 42433
/// @author iarkh@unipro.ru


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

class X {}
class Y extends X {}

void checkme1<T>(expected, [T? t]) {
  Expect.equals(expected, T);
}

void checkme2<T extends X>(expected, [T? t]) {
  Expect.equals(expected, T);
}

void checkme3<T extends Y>(expected, [T? t]) {
  Expect.equals(expected, T);
}

typedef void Test1<T>(dynamic, [T? t]);
typedef void Test2<T extends X>(dynamic, [T? t]);

main() {
  Test1 t1 = checkme1;
  t1(Object, dynamic);
  t1(Object);

  Test1<X> t2 = checkme2;
  t2(X, X());
  t2(X);

  Test1<Y> t3 = checkme3;
  t3(Y, Y());
  t3(Y);

  Test2 t4 = checkme1;
  t4(X, X());
  t4(X);

  Test2 t5 = checkme2;
  t5(X, X());
  t5(X);

  Test2 t6 = checkme2;
  t6(X, Y());
  t6(X);
}