vlib/v/checker/tests/chan_mut.vv:8:8: error: `v` is immutable, declare it with `mut` to make it mutable
    6 | fn f(ch chan mut St) {
    7 |     v := St{}
    8 |     ch <- v
      |           ^
    9 |     mut w := St{}
   10 |     ch <- w
vlib/v/checker/tests/chan_mut.vv:10:8: error: cannot push non-reference `St` on `chan mut St`
    8 |     ch <- v
    9 |     mut w := St{}
   10 |     ch <- w
      |           ^
   11 |     x := &St{}
   12 |     ch <- x
vlib/v/checker/tests/chan_mut.vv:12:8: error: `x` is immutable, declare it with `mut` to make it mutable
   10 |     ch <- w
   11 |     x := &St{}
   12 |     ch <- x
      |           ^
   13 |     mut y := St{}
   14 |     ch <- y
vlib/v/checker/tests/chan_mut.vv:14:8: error: cannot push non-reference `St` on `chan mut St`
   12 |     ch <- x
   13 |     mut y := St{}
   14 |     ch <- y
      |           ^
   15 |     mut z := &St{n: 7}
   16 |     // this works
