const (
    num_iterations = 10000
)

struct St {
mut:
    dummy  i64
    dummy2 u32
    dummy3 i64
    n      int
    dummy4 int
}

// this function gets an array of channels for `St` references
fn do_rec_calc_send(chs []chan mut St) {
    for {
        mut s := <-chs[0] or { break }
        s.n++
        chs[1] <- s
    }
}

fn test_channel_array_mut() {
    mut chs := [chan mut St{cap: 1}, chan mut St{}]
    spawn do_rec_calc_send(chs)
    mut t := &St{
        n: 100
    }
    for _ in 0 .. num_iterations {
        chs[0] <- t
        t = <-chs[1]
    }
    chs[0].close()
    assert t.n == 100 + num_iterations
}