8467ceff22
Add secondary span labels with no text to make it clear when there's a
mismatch bewteen the positional arguments in a format string and the
arguments to the macro. This shouldn't affect experienced users, but it
should make it easier for newcomers to more clearly understand how
`format!()` and `println!()` are supposed to be used.
```
error: 2 positional arguments in format string, but there is 1 argument
--> file8.rs:2:14
|
2 | format!("{} {}", 1);
| ^^ ^^ -
```
instead of
```
error: 2 positional arguments in format string, but there is 1 argument
--> file8.rs:2:14
|
2 | format!("{} {}", 1);
| ^^ ^^
```
|
||
|---|---|---|
| .. | ||
| format-string-error-2.rs | ||
| format-string-error-2.stderr | ||
| format-string-error.rs | ||
| format-string-error.stderr | ||
| send-sync.rs | ||
| send-sync.stderr | ||