Suggested fix has incorrect syntax

[sunjay]

Minimal reproduction: (Playground)

mod button {
    pub enum Button {}
}

mod button2 {
    pub struct Button();
}

use button::Button;

fn main() {
    use self::Button::*;
    let b = unimplemented!();
    match b {
        // match a different button that needs to be imported, but isn't yet
        Button(..) => unimplemented!(),
    }
}

This produces the error message:

error[E0532]: expected tuple struct/variant, found enum `Button`
  --> src/main.rs:16:9
   |
16 |         Button(..) => unimplemented!(),
   |         ^^^^^^ not a tuple struct/variant
   |
help: possible better candidate is found in another module, you can import it into scope
   |
11 | fn main() use button2::Button;
   |

error: aborting due to previous error

error: Could not compile `playground`.

To learn more, run the command again with --verbose.

Notice that the suggested fix is:

11 | fn main() use button2::Button;

This is incorrect syntax.

More Details

If you remove the use self::Button::* line, the error is normal again:

error[E0532]: expected tuple struct/variant, found enum `Button`
  --> src/main.rs:15:9
   |
15 |         Button(..) => unimplemented!(),
   |         ^^^^^^ not a tuple struct/variant
   |
help: possible better candidate is found in another module, you can import it into scope
   |
1  | use button2::Button;
   |

error: aborting due to previous error

error: Could not compile `playground`.

To learn more, run the command again with --verbose.

In fact, this only occurs if you have both a struct and an enum with the same name.

Meta

$ rustc --version --verbose
rustc 1.20.0 (f3d6973f4 2017-08-27)
binary: rustc
commit-hash: f3d6973f41a7d1fb83029c9c0ceaf0f5d4fd7208
commit-date: 2017-08-27
host: x86_64-unknown-linux-gnu
release: 1.20.0
LLVM version: 4.0

[kennytm]

Duplicate of #42548. Already fixed by #43929, and no repro on 1.21 (beta).

[sunjay]

Cool thanks!