vlib/v/checker/tests/generic_sumtype_invalid_variant.vv:5:7: error: `MultiGeneric<bool, int, string>` has no variant `u64`
    3 | fn main() {
    4 |     mut m := MultiGeneric<bool, int, string>(true)
    5 |     if m is u64 {
      |          ~~
    6 |         println('hi')
    7 |     }
vlib/v/checker/tests/generic_sumtype_invalid_variant.vv:8:7: error: `MultiGeneric<bool, int, string>` has no variant `X`
    6 |         println('hi')
    7 |     }
    8 |     if m is X {
      |          ~~
    9 |         println('hi again')
   10 |     }
