LanguageFeatures/nnbd/generics_A01_t05.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 The default bound of generic type parameters is treated as
/// [Object?].
///
/// @description It seems like it is not possible to obtain the value of the
/// default bound at runtime, we can only obtain the result of instantiation to
/// bound. So the test checks that if type parameter of the generic function
/// typedef is not clearly specified, it is treated as [dynamic] at runtime.
/// Typedef is in the form:
///   [typedef <typeIdentifier> <typeParameters> = <functionType>].
///
/// See also co19 issue #530.
/// @Issue 40367, 40368
///
/// @author iarkh@unipro.ru

// Requirements=nnbd-strong

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

typedef G1<T> = T Function();
typedef G2<T> = void Function(T);
typedef G3<T> = void Function<T1 extends T>();
typedef G4<T1, T2, T3> = T1 Function(T2, T3);
typedef G5<T1, T2, T3, T4> = T1 Function<TT extends T2>(T3, T4);

typedef G6<T> = void Function();
typedef G7<T1, T2, T3> = void Function();

typedef G3_expected = void Function<T extends dynamic>();
typedef G5_expected = dynamic Function<T extends dynamic>(dynamic, dynamic);

main() {
  Expect.equals(typeOf<G1<dynamic>>(), typeOf<G1>());
  Expect.equals(typeOf<G2<dynamic>>(), typeOf<G2>());
  Expect.equals(G3_expected, G3);
  Expect.equals(typeOf<G4<dynamic, dynamic, dynamic>>(), typeOf<G4>());
  Expect.equals(G5_expected, G5);
  Expect.equals(typeOf<G6<dynamic>>(), typeOf<G6>());
  Expect.equals(typeOf<G7<dynamic, dynamic, dynamic>>(), typeOf<G7>());
}