"A non-empty glob must import something with the glob's visibility" regression from stable/beta to nightly?

[utkarshkukreti]

The following program compiles on:

• rustc 1.13.0 (2c6933a 2016-11-07)
• rustc 1.14.0-beta.2 (e627a2e 2016-11-16)

but does not compile on:

• rustc 1.15.0-nightly (3bf2be9 2016-11-22)

mod foo {
  mod bar {
    pub use super::*;
  }
}

fn main() {}

Error:

rustc 1.15.0-nightly (3bf2be9ce 2016-11-22)
error: A non-empty glob must import something with the glob's visibility
 --> <anon>:3:13
  |
3 |     pub use super::*;
  |             ^^^^^^^^^

error: aborting due to previous error

Tested both locally and on https://play.rust-lang.org/.

I could not find any mention of this here or here.

[utkarshkukreti]

Found this while trying to fix https://github.com/utkarshkukreti/speculate.rs for the latest nightly (it only works on nightly). The library adds pub use super::*; to every generated module which probably triggered this.

[jseyfried]

@utkarshkukreti Thanks for the report!

This was intentional -- it was caused by #37127, which stabilized RFC 1560 (the error is described in the last paragraph of this section).

This error can always be fixed by removing the pub (i.e. pub use super::*; -> use super::*;).

We would have phased this in with a warning, but we found no breakage on crates.io when we measured it ~1 month ago. The pub use super::*; were probably added after we tested for breakage but before #37127 landed.

[utkarshkukreti]

Ah, I had used pub with use super::*; because the following code failed to compile previously (and still fails on Stable):

struct A;
mod foo {
    use super::*;
    mod bar {
        use super::*;
        fn a() -> A {
            A
        }
    }
}

But it looks like it does compile on the new Nightly now, so I'll just use that. Thanks @jseyfried!

[utkarshkukreti]

The pub use super::*; were probably added after we tested for breakage but before #37127 landed.

It's been there since January 2015 in my crate but my crate only works on nightly as it's a compiler plugin so it probably isn't tested by Crater.