Language/Generics/parameter_A05_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)* ‘>’
 * ...
 * Type parameters are declared in the type parameter scope of a class or
 * function. ... The type parameters of a generic class declaration [G] are also
 * in scope in the [extends] and [implements] clauses of [G] (if these exist)
 * and in the body of [G].
 * @description Checks that class type parameter is in the scope of its body.
 * @author iarkh@unipro.ru
 */

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

class A {}
class B extends A {}

class D<X extends A> {
  X? testme;
}

main() {
  dynamic a = A();
  dynamic b = B();

  D().testme = a;
  D().testme = b;

  D<A>().testme = a;
  D<A>().testme = b;

  D<B>().testme = b;
  Expect.throws(() => D<B>().testme = a);
}