vlib/v/parser/tests/postfix_err_a.vv:5:8: warning: `++` operator can only be used as a statement
    3 | fn test_postfix() {
    4 |     mut x := 1
    5 |     _ = (x++)
      |           ~~
    6 |     x--, x-- // OK
    7 |     f(x++)
vlib/v/parser/tests/postfix_err_a.vv:7:5: warning: `++` operator can only be used as a statement
    5 |     _ = (x++)
    6 |     x--, x-- // OK
    7 |     f(x++)
      |        ~~
    8 |     a := [x]
    9 |     _ = a[x--]
vlib/v/parser/tests/postfix_err_a.vv:9:9: warning: `--` operator can only be used as a statement
    7 |     f(x++)
    8 |     a := [x]
    9 |     _ = a[x--]
      |            ~~
   10 | }
vlib/v/parser/tests/postfix_err_a.vv:1:6: notice: unused parameter: `i`
    1 | fn f(i int) {}
      |      ^
    2 | 
    3 | fn test_postfix() {