library test;

T f<T>() => throw '';

class A {}

class B extends A {
  B operator *(B v) => throw '';
  B operator +(C v) => throw '';
  B operator -(int i) => throw '';
  C operator &(A v) => throw '';
}

class C extends B {}

main() {}

void test(B local, B? local2, B? local3) {}