library /*isNonNullableByDefault*/;
import self as self;
import "dart:core" as core;

abstract class A<X extends core::Object? = dynamic> extends core::Object {
  synthetic constructor •() → self::A<self::A::X%>
    : super core::Object::•()
    ;
  method foo<covariant-by-class Y extends self::A::X%>() → void {}
}
class B<Z extends core::Object? = dynamic> extends self::A<self::B::Z%> {
  synthetic constructor •() → self::B<self::B::Z%>
    : super self::A::•()
    ;
}
static method main() → void {
  new self::B::•<core::Object>().{self::A::foo}<core::int>(){() → void};
}