Language/Types/Static_Types/malformed_type_t01.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 malformed iff:
 * • T has the form id or the form prefix.id, and in the enclosing lexical
 *   scope, the name id (respectively prefix.id) does not denote a type.
 * • T denotes a type variable in the enclosing lexical scope, but occurs in
 *   the signature or body of a static member.
 * • T is a parameterized type of the form G<S1, ..., Sn>, and G is malformed.
 * • T denotes declarations that were imported from multiple imports clauses.
 * Any use of a malformed type gives rise to a static warning. A malformed type
 * is then interpreted as dynamic by the static type checker and the runtime
 * unless explicitly specified otherwise.
 * @description Checks that it is a compile error if a malformed type is
 * used in a subtype test.
 * @author kaigorodov
 */

class C<T, U, V> {}
class Bounded<T extends num> {}
class BoundedInt<T extends int> {}

main() {
  null is UnknownType;                            //# 01: compile-time error

  // C<int, double, UnknownType> is not malformed, see
  // (Types/Parameterized Types)
  // UnknownType is treated as dynamic and parameterized type is
  // C<int,double,dynamic>

  C<int, double, UnknownType> x = new C();        //# 02: compile-time error
  null is C<int, double, UnknownType>;            //# 03: compile-time error
  Bounded<String> x2 = new Bounded();             //# 04: compile-time error
  BoundedInt<num> x3 = new BoundedInt();          //# 05: compile-time error
  C<Bounded<String>, C, C> x4 = new C();          //# 06: compile-time error
  C<C<UnknownType, int, int>, C, C> x5 = new C(); //# 07: compile-time error
}