| error: expected string literal | |
| --> tests/ui/concat-display.rs:8:17 | |
| | | |
| 8 | #[error(concat!("invalid ", $what))] | |
| | ^^^^^^ | |
| ... | |
| 13 | error_type!(Error, "foo"); | |
| | ------------------------- in this macro invocation | |
| | | |
| = note: this error originates in the macro `error_type` (in Nightly builds, run with -Z macro-backtrace for more info) |