pub struct Vector {
    vec []f64
}

pub fn (a Vector) + (b Vector) Vector {
    size := a.vec.len
    if size != b.vec.len {
        panic('unequal sizes')
    }
    mut c := []f64{len: size}
    for i in 0 .. size {
        c[i] = a.vec[i] + b.vec[i]
    }
    return Vector{
        vec: c
    }
}

type Vec = Vector

fn test_alias_operator_overloading() {
    a := Vec{
        vec: [0.1, 0.2]
    }
    b := Vec{
        vec: [0.3, 0.2]
    }
    c := a + b
    println(c)
    assert c.vec == [0.4, 0.4]
}