Enable path trimming for error messages in clippy

[veber-alex]

Consider this code:

fn main() {
    let mut a = vec![String::new()];
    let b = vec![10];

    a = b;
}

When using "cargo check" the error message uses trimmed type paths and is much more readable:

error[E0308]: mismatched types
 --> src/main.rs:5:9
  |
5 |     a = b;
  |         ^ expected struct `String`, found integer
  |
  = note: expected struct `Vec<String>`
             found struct `Vec<{integer}>`

But when running "cargo clippy" you get this output:

error[E0308]: mismatched types
 --> src/main.rs:5:9
  |
5 |     a = b;
  |         ^ expected struct `std::string::String`, found integer
  |
  = note: expected struct `std::vec::Vec<std::string::String>`
             found struct `std::vec::Vec<{integer}>`

I have rust-analyzer set to always run clippy instead of check and as a result I get worse error messages inside the IDE.
Please consider enabling path trimming for clippy.

[xFrednet]

This is most likely related to #6385

This is the second issue in a short time that came up in this regard, it might be that there has been a change that increased the frequency 🤔

[veber-alex]

Hi, any updates on this issue?
According to rust-lang/rust@c5a6131 path trimming is not enabled for clippy for a reason but having some option to enable it anyway would be nice.
Unfortunately the obvious way shown below doesn't work.
RUSTFLAGS="-Ztrim-diagnostic-paths=yes" cargo clippy

[xFrednet]

Hey, there hasn't been any progress to my knowledge, probably also because as with #6385 there hasn't been any leads where to start looking for the issue. Your linked commit could have something todo with it and is a new idea to look into. 🙃

[camsteffen]

I opened a tracking issue for this at #7798 since there is some refactoring needed to support this.