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

class C extends core::Object {
  field core::num? x = null;
  synthetic constructor •() → self::C
    : super core::Object::•()
    ;
}
class D extends core::Object implements self::C {
  covariant-by-declaration field core::int? x = null;
  synthetic constructor •() → self::D
    : super core::Object::•()
    ;
}
class E extends core::Object implements self::D {
  covariant-by-declaration field core::int? x = null;
  synthetic constructor •() → self::E
    : super core::Object::•()
    ;
}
static method main() → dynamic {}