Language/Generics/parameter_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
 *    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 {}

void func1<T extends A>() {}
void func2<T extends B>() {}
void func3<T extends C>() {}

main() {
  func1();
  func1<A>();
  func1<B>();
  func1<C>();

  func2();
  func2<A>();
//^
// [cfe] Type argument 'A' doesn't conform to the bound 'B' of the type variable 'T' on 'func2'.
//      ^
// [analyzer] COMPILE_TIME_ERROR.TYPE_ARGUMENT_NOT_MATCHING_BOUNDS
  func2<B>();
  func2<C>();

  func3();
  func3<A>();
//^
// [cfe] Type argument 'A' doesn't conform to the bound 'C' of the type variable 'T' on 'func3'.
//      ^
// [analyzer] COMPILE_TIME_ERROR.TYPE_ARGUMENT_NOT_MATCHING_BOUNDS
  func3<B>();
//^
// [cfe] Type argument 'B' doesn't conform to the bound 'C' of the type variable 'T' on 'func3'.
//      ^
// [analyzer] COMPILE_TIME_ERROR.TYPE_ARGUMENT_NOT_MATCHING_BOUNDS
  func3<C>();
}