dart / co19 / 65b069b616085fc8e643812b4890a1021daabe3b / . / Language / Generics / typedef_A08_t02.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 A generic type alias is a declaration [D] of one of the following | |

* forms: | |

* m typedef id<X1 extends B1, . . . , Xs extends Bs> = T; | |

* m typedef S? id<X1 extends B1, . . . , Xs extends Bs>( | |

* T1 p1, . . . , Tn pn, [Tn+1 pn+1, . . . , Tn+k pn+k]); | |

* m typedef S? id<X1 extends B1, . . . , Xs extends Bs>( | |

* T1 p1, . . . , Tn pn, {Tn+1 pn+1, . . . , Tn+k pn+k}); | |

* where [m] is derived from metadata, [T] is a type, and [S?] is a type or the | |

* empty string. Let [S0] be [S?] if it is a type, otherwise let [S0] be | |

* [dynamic]. The associated type of [D], call it [F], is, respectively: | |

* T | |

* S0 Function(T1, . . . , Tn, [Tn+1, . . . , Tn+k]) | |

* S0 Function(T1, . . . , Tn, {Tn+1 xn+1, . . . , Tn+k xn+k}) | |

* ... | |

* Moreover, let [T1], . . . , [Tl] be types and let [U] be the parameterized | |

* type id<T1, . . . , Tl> in a location where [id] denotes [D]. ... It is a | |

* compile-time error if [U] is not well-bounded | |

* @description Checks that compile error is thrown if [U] is not well-bounded. | |

* @Issue 36959 | |

* @author iarkh@unipro.ru | |

*/ | |

class A<X extends A<X>> {} | |

typedef AAlias<T extends A<T>> = T Function<T>(); | |

main() { | |

AAlias a1; | |

AAlias<A> a2; | |

AAlias<A<Null>> a3; | |

AAlias<A<dynamic>> a4; | |

AAlias<A<Object>> a5; | |

AAlias<A<int>> a6; //# 01: compile-time error | |

AAlias<int> a7; //# 02: compile-time error | |

AAlias<dynamic> a8; | |

} |