vlib/v/checker/tests/if_mut_with_immutable_var_err.vv:5:9: error: `i` is immutable, declare it with `mut` to make it mutable
    3 | fn main() {
    4 |     i := Int(0)
    5 |     if mut i is int {
      |            ^
    6 |         i = 1
    7 |     } else if mut i is u8 {
vlib/v/checker/tests/if_mut_with_immutable_var_err.vv:7:16: error: `i` is immutable, declare it with `mut` to make it mutable
    5 |     if mut i is int {
    6 |         i = 1
    7 |     } else if mut i is u8 {
      |                   ^
    8 |         i = 2
    9 |     }