1 error: invalid format string: unmatched `}` found
2 --> $DIR/format-concat-span.rs:13:13
4 LL | format!(concat!("abc}"));
5 | ^^^^^^^^^^^^^^^ unmatched `}` in format string
7 = note: if you intended to print `}`, you can escape it using `}}`
8 = note: this error originates in the macro `concat` (in Nightly builds, run with -Z macro-backtrace for more info)
10 error: aborting due to previous error