Duplicated diagnostics when import is ambiguous

[chenyukang]

Given the following code:

use self::A::*;
use self::B::*;

enum A {
    V
}

enum B {
    V
}

use V;

fn main() {}

The current output is:

Compiling playground v0.0.1 (/playground)
error[[E0659]](https://doc.rust-lang.org/nightly/error-index.html#E0659): `V` is ambiguous
  --> src/main.rs:12:5
   |
12 | [use V;](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2021#)
   |     ^ ambiguous name
   |
   = note: ambiguous because of multiple glob imports of a name in the same module
note: `V` could refer to the variant imported here
  --> src/main.rs:1:5
   |
1  | [use self::A::*;](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2021#)
   |     ^^^^^^^^^^
   = help: consider adding an explicit import of `V` to disambiguate
note: `V` could also refer to the variant imported here
  --> src/main.rs:2:5
   |
2  | [use self::B::*;](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2021#)
   |     ^^^^^^^^^^
   = help: consider adding an explicit import of `V` to disambiguate

error[[E0659]](https://doc.rust-lang.org/nightly/error-index.html#E0659): `V` is ambiguous
  --> src/main.rs:12:5
   |
12 | [use V;](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2021#)
   |     ^ ambiguous name
   |
   = note: ambiguous because of multiple glob imports of a name in the same module
note: `V` could refer to the unit variant imported here
  --> src/main.rs:1:5
   |
1  | [use self::A::*;](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2021#)
   |     ^^^^^^^^^^
   = help: consider adding an explicit import of `V` to disambiguate
note: `V` could also refer to the unit variant imported here
  --> src/main.rs:2:5
   |
2  | [use self::B::*;](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2021#)
   |     ^^^^^^^^^^
   = help: consider adding an explicit import of `V` to disambiguate

warning: unused import: `self::B::*`
 --> src/main.rs:2:5
  |
2 | [use self::B::*;](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2021#)
  |     ^^^^^^^^^^
  |
  = note: `#[warn(unused_imports)]` on by default

warning: unused import: `V`
  --> src/main.rs:12:5
   |
12 | [use V;](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2021#)
   |     ^

For more information about this error, try `rustc --explain E0659`.
warning: `playground` (bin "playground") generated 2 warnings
error: could not compile `playground` due to 2 previous errors; 2 warnings emitted

There are duplicated diagnostics in output, Ideally the output should look like:

error[[E0659]](https://doc.rust-lang.org/nightly/error-index.html#E0659): `V` is ambiguous
  --> src/main.rs:12:5
   |
12 | [use V;](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2021#)
   |     ^ ambiguous name
   |
   = note: ambiguous because of multiple glob imports of a name in the same module
note: `V` could refer to the variant imported here
  --> src/main.rs:1:5
   |
1  | [use self::A::*;](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2021#)
   |     ^^^^^^^^^^
   = help: consider adding an explicit import of `V` to disambiguate
note: `V` could also refer to the variant imported here
  --> src/main.rs:2:5
   |
2  | [use self::B::*;](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2021#)
   |     ^^^^^^^^^^
   = help: consider adding an explicit import of `V` to disambiguate


warning: unused import: `self::B::*`
 --> src/main.rs:2:5
  |
2 | [use self::B::*;](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2021#)
  |     ^^^^^^^^^^
  |
  = note: `#[warn(unused_imports)]` on by default

warning: unused import: `V`
  --> src/main.rs:12:5
   |
12 | [use V;](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2021#)
   |     ^

[lyming2007]

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