pub mod test {
    pub struct A;
    pub struct B;
    pub struct Foo<T>(::std::marker::PhantomData<T>);

    impl Foo<A> {
        fn foo(a: usize) -> usize {
            a
        }
    }

    impl Foo<B> {
        fn foo(a: usize, b: usize) -> usize {
            b
        }
    }
}

fn main() {
    test::Foo::<test::B>::foo(0, 0);
}