Language/Types/Interface_Types/subtype_t37.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 two generic types are not assignable even if just
/// one type argument is not assignable. Using complex generic types.
/// @author iefremov


class I<A, B, C> {}
class J<A, B, C> extends I<A, B, C> {}
class K extends J {}
class C extends K {}

typedef J   f(I<J, List<Map>,           num> i, [List j]);
typedef K f_1(I<K, List<Map<int, num>>, int> i, [List<Map> j]);

I<f, num, List<Map<num, Map<int, double>>>>? checker() {}

main() {
//  I<f_1, int, List<Map<int, Map<int, int>>>> i = new I<f, num, List<Map<num, Map<int, double>>>>();
//                                     ^^^     <=/=>                                    ^^^
  I<f_1, int, List<Map<int, Map<int, int>>>>? i = checker();
//                                                ^
// [analyzer] unspecified
// [cfe] unspecified
}