#![feature(decl_macro)]

macro assert_type {
    ($ty:ty, $expected_size:expr) => {
        {
            fn _assert_type() {
                std::mem::transmute::<$ty, [u8; $expected_size]>;
            }
        }
    };
}

fn main() {
    assert_type!(u64, 8);
    assert_type!(u32, 4);
    //bassert_type!(u16, 4);
}