Build 201210100934

After refactoring, there will be a compilation error.

interface A1<T> {
    T m(T a);
}

// Invoke 'Use Supertype Where Possible' (select 'A1')
class C1 implements A1<C1> {
    public C1 m(C1 a) {
        return null;
    }
}

--------------
After refactoring:

interface A1<T> {
    T m(T a);
}

class C1 implements A1<C1> {
    public C1 m(A1 a) { //should not change to A1
        return null;
    }
}