Fixing unused imports

[rohitjoshi]

I really like rustfix and expectations are more :)

cargo build identifies unused imports. I would like to see rustfix provides similar suggestion and remove these unused imports.

e.g.

warning: unused import: `std::io::prelude::*`
  --> src/tiso/tiso_msg.rs:10:5
   |
10 | use std::io::prelude::*;
   |     ^^^^^^^^^^^^^^^^^^^

warning: unused import: `std::fmt`
  --> src/tiso/tiso_msg.rs:13:5
   |
13 | use std::fmt;
   |     ^^^^^^^^

[oli-obk]

This should be fixed in rustc by creating an empty suggestion

[killercup]

Yeah, I've been missing that too! :)

The strategy is to suggest replacing the unused import with an empty string. If it is the only item in the use (i.e., std::fs in use std::fs; is unused, in contrast to File in use std::fs::{File, copy} is unused), remove the whole use statement.

This suggestion needs to be implemented in rustc, probably here.

I couldn't find an open issue there, you should open one! Feel free to copy this comment too if you like :) (Maybe mention rust-lang/rust#42823 as it tracks a few diagnostic things already.)

Edit: Damn you @oli-obk I'm writing a long comment here and you just waltz in and say the same thing! Again! :P

[rohitjoshi]

It would be good to remove unused crates extern crate xxx