Language/Types/Interface_Types/subtype_t43.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 type T is more specific than a type S, written T << S, if one
/// of the following conditions is met:
///  • T is S.
///  • T is ⊥
///  • S is dynamic.
///  • S is a direct supertype of T.
///  • T is a type parameter and S is the upper bound of T.
///  • T is a type parameter and S is Object.
///  • T is of the form I<T1, ..., Tn > and S is of the form I <S1, ..., Sn>
///    and Ti << Si 1 <= i <= n.
///  • T and S are both function types, and T << S under the rules of section
///    (Types/Function Types).
///  • T is a function type and S is Function.
///  • T << U and U << S.
/// << is a partial order on types. T is a subtype of S, written T <: S, iff
/// [⊥/Dynamic]T << S.
/// . . .
/// An interface type T may be assigned to a type S, written T <=> S, if either
/// T <: S or S <: T.
/// @description Checks that a parameterized generic g1 is not a subtype of
/// another parameterized generic g2 (same raw type) if g1's only type parameter
/// is not a subtype of g2's type parameter.
/// @author iefremov

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


class G<T> {}

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


main() {
  Expect.isFalse(new G<B>() is G<C>);
  Expect.isFalse(new G<A>() is G<B>);
  Expect.isFalse(new G<A>() is G<C>);
  Expect.isFalse(new G<Object>() is G<B>);
  Expect.isFalse(new G<int>() is G<B>);
  Expect.isFalse(new G<int>() is G<double>);
  Expect.isFalse(new G<int>() is G<String>);
}