Regression when doc string invokes a macro which is defined within the same module

[danielhenrymantilla]

Code

I tried this code:

mod module {
    #![doc = foo!()]

    macro_rules! foo {() => (
        ""
    )}
}

I expected to see this happen:

✅

Instead, this happened:

error: cannot find macro `foo` in this scope
 --> src/lib.rs:2:14
  |
2 |     #![doc = foo!()]
  |              ^^^ consider moving the definition of `foo` before this call
  |
note: a macro with the same name exists, but it appears later at here
 --> src/lib.rs:4:18
  |
4 |     macro_rules! foo {
  |                  ^^^

Remark

Note that this problem still does not occur at the top-most level.

That is, removing mod module { above makes it work:

#![doc = foo!()]

macro_rules! foo {() => (
    ""
)}

Version it worked on

It most recently worked on: +nightly-2024-04-27

Version with regression

rustc --version --verbose:

+nightly-2024-04-28

---

@rustbot modify labels: +regression-from-stable-to-nightly -regression-untriaged

[lqd]

IIUC this is also on beta 1.79 but I don't think it's in 1.78, which becomes stable on Thursday.

[danielhenrymantilla]

Good point, in three (?) days it will become a

[lqd]

beta 1.79 is already out IIRC?

[bjorn3]

Why did it work at all? The doc comment is defined earlier in the source order than the macro, so it shouldn't be able to see the macro.

[lqd]

This is from #124382 cc @petrochenkov