LanguageFeatures/Simple-bounds/static/class_l1_t01.dart

/**
 * @assertion Let [G] be a generic class or parameterized type alias with formal
 * type parameter declarations [F1] .. [Fk] containing formal type parameters
 * [X1] .. [Xk] and bounds [B1] .. [Bk]. We say that the formal type parameter
 * [Xj] has a simple bound when one of the following requirements is satisfied:
 * [Bj] is omitted.
 * [Bj] is included, but does not contain any of [X1] .. [Xk]. If [Bj] contains
 * a type [T] on the form qualified (for instance, [C] or [p.D]) which denotes a
 * generic class or parameterized type alias [G1] (that is, [T] is a raw type),
 * every type argument of [G1] has a simple bound.
 * @description Checks that simple bounds are correct for the very simple case:
 *  [A<X extends num>]
 * @author iarkh@unipro.ru
 */

typedef F<X> = void Function<Y extends X>();
F<X> toF<X>(X x) => null;

class A<X extends num> {}

main() {
  A source;
  var fsource = toF(source);
  F<A<num>> target = fsource;

  F<A<int>>     target1 = fsource;  //# 01: compile-time error
  F<A<dynamic>> target2 = fsource;  //# 02: compile-time error
  F<A<Null>>    target3 = fsource;  //# 03: compile-time error
  F<A<Object>>  target4 = fsource;  //# 04: compile-time error
  A();
}