bors a2ea66bea6 Auto merge of #11400 - hi-rustin:rustin-patch-fix-error, r=epage
Add error message when `cargo fix` on an empty repo

### What does this PR try to resolve?

close https://github.com/rust-lang/cargo/issues/11380

Add error message when `cargo fix` on an empty repo.

### How should we test and review this PR?

- [x] unit test

```sh
set -eux

cargo +nightly new repro
cd repro
echo "fn main() { let _ = 0.clone(); }" > src/main.rs
cargo fix
```
2022-11-28 13:01:15 +00:00
..