Language/Generics/parameter_A01_t03.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
///    typeParameter ::= metadata identifier (extends typeNotVoid)?
///    typeParameters ::= ‘<’ typeParameter (‘,’ typeParameter)* ‘>’
/// A type parameter [T] may be suffixed with an [extends] clause that specifies
/// the upper bound for [T].
/// @description Statically checks that [extends] clause specifies upper bound
/// for the class type parameter
/// @author iarkh@unipro.ru

class A {} 
class B extends A {}
class C extends B {}

class D<T> {}

typedef Alias1<T extends A> = D<T>;
typedef Alias2<T extends B> = D<T>;
typedef Alias3<T extends C> = D<T>;

main() {
  D d11 = Alias1();
  D d12 = Alias1<A>();
  D d13 = Alias1<B>();
  D d14 = Alias1<C>();

  D d21 = Alias2();
  D d22 = Alias2<A>();
//               ^
// [analyzer] unspecified
// [cfe] unspecified
  D d23 = Alias2<B>();
  D d24 = Alias2<C>();

  D d31 = Alias3();
  D d32 = Alias3<A>();
//               ^
// [analyzer] unspecified
// [cfe] unspecified

  D d33 = Alias3<B>();
//               ^
// [analyzer] unspecified
// [cfe] unspecified

  D d34 = Alias3<C>();
}