error[E0080]: evaluation of constant value failed
 --> tests/ui/labels/bogus_label_name_in_attr.rs:4:19
  |
4 | #[metrics(label = "what?", rename_all = "snake_case")]
  |                   ^^^^^^^ the evaluated program panicked at 'Label name `what?` is invalid: name contains a disallowed char '?' at position 4; allowed chars are [_a-z0-9]', $DIR/tests/ui/labels/bogus_label_name_in_attr.rs:4:19