Should importing a `#[macro_export] macro_rules!` macro trigger `unused_imports`?

[SabrinaJewson]

I tried this code:

#[macro_export]
macro_rules! owo {
    () => {};
}
mod m {
    use crate::owo;
    owo!();
}

On stable, cargo check completes successfully. On Nightly, it produces a warning:

warning: unused import: `crate::owo`
 --> src/lib.rs:6:9
  |
6 |     use crate::owo;
  |         ^^^^^^^^^^
  |
  = note: `#[warn(unused_imports)]` (part of `#[warn(unused)]`) on by default

Nightly is correct in the sense that the import is, in fact, unnecessary, and the code builds with or without it. But I’m not sure whether this is a bug or not. I always put the import in because I like to think about modules and don’t like to think about the arcane macro_rules! scoping rules, but given that I can’t disable those rules this might be a losing battle…

Meta

rustc --version --verbose:

rustc 1.90.0 (1159e78c4 2025-09-14)
binary: rustc
commit-hash: 1159e78c4747b02ef996e55082b704c09b970588
commit-date: 2025-09-14
host: x86_64-unknown-linux-gnu
release: 1.90.0
LLVM version: 20.1.8

rustc +nightly --version --verbose:

rustc 1.92.0-nightly (53a741fc4 2025-10-16)
binary: rustc
commit-hash: 53a741fc4b8cf2d8e7b1b2336ed8edf889db84f4
commit-date: 2025-10-16
host: x86_64-unknown-linux-gnu
release: 1.92.0-nightly
LLVM version: 21.1.3

[kpreid]

given that I can’t disable those rules this might be a losing battle…

In particular, it might be desirable to help the user learn that they can't not have the macro in scope. Might.

[ogoffart]

Re-using this issue as this seems related:
I'm seeing this warning in nightly, this is a small reproduction:

#![doc = m!()]
macro_rules! m { () => {"Doc comment generated from macro"} }
use m;

In nightly get the warning:

warning: unused import: `m`
 --> src/lib.rs:3:5
  |
3 | use m;
  |     ^

Note that without the use m; I'm getting an error (both stable and nightly): error: cannot find macro `m` in the current scope when looking from the crate root
So i would say that the import is necessary.

[petrochenkov]

#147823 (comment) is the unused_imports lint becoming more precise (due to #145113), but #147823 (comment) is a legitimate bug.