Reference to std::fmt::Debug not using full path in "multiple applicable items in scope" error

[5225225]

Given the following code: https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=970c9bebd80f042e27af0cdfb3309579

#![allow(unused_imports, unreachable_code)]
use std::fmt::{Debug as _, Display as _};

fn main() {
    0u32.fmt(todo!());
}

The current output is:

Compiling playground v0.0.1 (/playground)
error[E0034]: multiple applicable items in scope
 --> src/main.rs:5:10
  |
5 |     0u32.fmt(todo!());
  |          ^^^ multiple `fmt` found
  |
  = note: candidate #1 is defined in an impl of the trait `Debug` for the type `u32`
  = note: candidate #2 is defined in an impl of the trait `std::fmt::Display` for the type `u32`
help: disambiguate the associated function for candidate #1
  |
5 |     Debug::fmt(&0u32, _);
  |     ~~~~~~~~~~~~~~~~~~~~
help: disambiguate the associated function for candidate #2
  |
5 |     std::fmt::Display::fmt(&0u32, _);
  |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

For more information about this error, try `rustc --explain E0034`.
error: could not compile `playground` due to previous error

Ideally the output should look like:

Compiling playground v0.0.1 (/playground)
error[E0034]: multiple applicable items in scope
 --> src/main.rs:5:10
  |
5 |     0u32.fmt(todo!());
  |          ^^^ multiple `fmt` found
  |
  = note: candidate #1 is defined in an impl of the trait `std::fmt::Debug` for the type `u32`
  = note: candidate #2 is defined in an impl of the trait `std::fmt::Display` for the type `u32`
help: disambiguate the associated function for candidate #1
  |
5 |     std::fmt::Debug::fmt(&0u32, _);
  |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
help: disambiguate the associated function for candidate #2
  |
5 |     std::fmt::Display::fmt(&0u32, _);
  |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

For more information about this error, try `rustc --explain E0034`.
error: could not compile `playground` due to previous error

If you apply the original suggestion, you get a compile error, because Debug (the trait) is not in scope. Debug (the derive macro) is, however. I suspect that's what's causing this? And why it doesn't happen for Display, because Display doesn't have a derive macro.

@rustbot label D-invalid-suggestion