Derive breaks wildcard import

[dtolnay]

#![allow(unused_imports, dead_code)]

//use crate::a::Type;  // <-- uncommenting makes it work
use crate::a::*;

pub type Repro = Type;

mod a {
    use crate::b::*;

    #[derive(Clone)]  // <-- commenting makes it work
    pub struct Type;
}

mod b {
    pub struct Type;
}

fn main() {}

$ rustc src/lib.rs --edition=2018
error[E0412]: cannot find type `Type` in this scope
 --> src/lib.rs:6:18
  |
6 | pub type Repro = Type;
  |                  ^^^^ not found in this scope
  |
help: consider importing one of these items
  |
4 | use crate::a::Type;
  |
4 | use crate::b::Type;
  |

Observations:

• Changing use crate::a::* to use crate::a::Type makes it work. My expectation would be that * includes Type.
• Removing the derive on Type makes the wildcard import work.
• Also reproduces with a proc macro derive in place of standard library builtin derive. Tested with derive(serde::Serialize).
• Does not reproduce with handwritten Clone impl, only with derive.
• Reproduces on every compiler since 1.15.0 through most recent nightly.

[dtolnay]

Mentioning @petrochenkov @davidhewitt since you have been active in name resolution recently. (This is not a new bug but you might have insight.)

[petrochenkov]

Looks similar to #56593, this is a long standing issue.

[dtolnay]

Thanks, good call. I failed to find that one searching for variations of "wildcard" and "derive".