rustc incorrectly suggests a `pub(crate)` on an enum variant or trait item is "unnecessary", implying it is permitted

[mcy]

See https://godbolt.org/z/8bWh445hh

Given

enum Foo {
  pub(crate) Bar,
  Baz {
    pub(crate) x: i32,
  },
}

I get

error[E0449]: unnecessary visibility qualifier
 --> <source>:2:3
  |
2 |   pub(crate) Bar,
  |   ^^^^^^^^^^

error[E0449]: unnecessary visibility qualifier
 --> <source>:4:5
  |
4 |     pub(crate) x: i32,
  |     ^^^^^^^^^^

error: aborting due to 2 previous errors

rustc correctly describes these as "unnecessary" when they are a plain pub:

error[E0449]: unnecessary visibility qualifier
 --> <source>:2:3
  |
2 |   pub Bar,
  |   ^^^ `pub` not permitted here because it's implied

rustc should instead state that non-pub visibility qualifiers are not permitted, rather than being unnecessary. I suggest a diagnostic like

error[E0449]: visibility qualifiers are not permitted inside of enums
 --> <source>:2:3
  |
2 |   pub(crate) Bar,
  |   ^^^^^^^^^^ 

(There is a similar diagnostic bug around putting pub(crate) or pub(self) on trait items.)

[ElectrifyPro]

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