library test;

class C<T> {
  F<T> g4() => this.f;
  void f(T x) {}
  void g1(T x) {}
  void g2(T x) {}
  void g3(C<T> c, T x) {}
}

class D extends C<int> {}

class E extends C<num> {
  void f(covariant int x) {}
}

main() {}
test() {}
typedef F<T>(T x);