// @dart = 2.9 | |
library test; | |
import 'dart:async'; | |
T f<T>() => null; | |
class B<T> { | |
D<T> operator [](E<T> x) => null; | |
} | |
class C<U> extends B<Future<U>> { | |
E<Future<U>> operator [](Object x) => null; | |
void h() {} | |
} | |
class D<T> {} | |
class E<T> extends D<T> {} | |
main() {} |