highlight interpolation and new line

[Dushistov]

For println!("path {}", 1); rust-mode does highlight:

But if add new line symbol between ( and " rust-mode doesn't highlight:

rustfmt often inserts new lines between ( and " for format! and println!

[Dushistov]

/cc @Aankhen

[Aankhen]

Thanks for the report! I think this is because Font Lock doesn’t recognize multiline constructs the same way. If I’ve understood correctly, I’ll need to add something to font-lock-extend-region-functions to make this work correctly. I’ll try to find some time to do that.