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

class B extends core::Object {
  field core::Object? _x;
  synthetic constructor •() → self::B
    ;
  method f([core::num x = 10]) → void
    ;
  method g({core::num x = 20}) → void
    ;
  method check(core::Object expectedValue) → void
    ;
}
abstract class I<T extends core::Object? = dynamic> extends core::Object {
  synthetic constructor •() → self::I<self::I::T%>
    ;
  abstract method f([covariant-by-class self::I::T% x = null]) → void;
  abstract method g({covariant-by-class self::I::T% x = null}) → void;
}
class C extends self::B implements self::I<core::num> {
  synthetic constructor •() → self::C
    ;
  forwarding-stub method f([covariant-by-class core::num x]) → void
    return super.{self::B::f}(x);
  forwarding-stub method g({covariant-by-class core::num x}) → void
    return super.{self::B::g}(x: x);
}
static method main() → dynamic
  ;