为什么后增量操作符不用于返回int的方法?

public void increment(){
    int zero = 0;

    int oneA = zero++; // Compiles

    int oneB = 0++; // Doesn't compile

    int oneC = getInt()++; // Doesn't compile
}

private int getInt(){
    return 0;
}
public void increment(){
    int zero = 0;