error: Discriminant overflow for representation
  --> tests/ui/numerical_discriminant_error.rs:15:15
   |
15 |     Variant = 255,
   |               ^^^

error[E0370]: enum discriminant overflowed
  --> tests/ui/numerical_discriminant_error.rs:16:5
   |
16 |     Variant2
   |     ^^^^^^^^ overflowed on value after 255
   |
   = note: explicitly set `Variant2 = 0` if that is desired outcome