vlib/v/checker/tests/assign_mut.vv:3:11: error: expecting `:=` (e.g. `mut x :=`)
    1 | fn main() {
    2 |     mut z := 1
    3 |     mut z = 1
      |           ^
    4 |     mut i := 2
    5 |     i, mut z = 2,3
