error: attribute should have a single field `expected = "value"`
 --> tests/ui-nightly/invalid_should_panic_attr.rs:4:32
  |
4 | #[should_panic(expected = "!", bogus = true)]
  |                                ^^^^^

error: expected string literal
  --> tests/ui-nightly/invalid_should_panic_attr.rs:10:27
   |
10 | #[should_panic(expected = 777)]
   |                           ^^^