vlib/v/checker/tests/invalid_mut.vv:3:5: error: the `mut` keyword is invalid here
    1 | fn main() {
    2 |     mut x := 0
    3 |     if mut x == 0 {
      |        ~~~
    4 |         println(true)
    5 |     }
vlib/v/checker/tests/invalid_mut.vv:6:10: error: the `mut` keyword is invalid here
    4 |         println(true)
    5 |     }
    6 |     if 0 == mut x {
      |             ~~~
    7 |         println(true)
    8 |     }
