Trait definitions with missing generic parameters suggest missing enum variant

Code

pub struct Point<A> {
    x: A,
}
pub trait MyTrait1 {
    fn fun(&self, p: Point<A>);
}
pub struct MyStruct;
impl<A> MyTrait1 for Point<A> {
    fn fun(&self, p: Point<A>) {
        todo!();
    }
}

fn main() {
    todo!();
}

Current output

error[E0412]: cannot find type `A` in this scope
 --> src/main.rs:5:28
  |
5 |     fn fun(&self, p: Point<A>);
  |                            ^ not found in this scope
  |
help: there is an enum variant `futures_0_1_31::future::Either::A`; try using the variant's enum
  |
5 |     fn fun(&self, p: Point<futures_0_1_31::future::Either>);
  |                            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

For more information about this error, try `rustc --explain E0412`.
error: could not compile `playground` (bin "playground") due to previous error

Desired output

error[E0412]: cannot find type `A` in this scope
 --> src/main.rs:5:28
  |
5 |     fn fun(&self, p: Point<A>);
  |                            ^ not found in this scope
  |
help: you might be missing a type parameter
  |
4 | pub trait MyTrait1<A> {
  |                   +++

For more information about this error, try `rustc --explain E0412`.
error: could not compile `playground` (bin "playground") due to previous error

Rationale and extra context

I'm using generic parameters and then noticed that in this code, when I use A as a generic parameter, the compiler suggested to add a enum variant. I'm not sure what this means and it still doesn't compile after following the suggestion. I've tried some earlier versions of rustc and that suggestion doesn't come up either.

If I use the generic parameter T, the compiler does not show this suggestion. It only output an error without any suggestion, like this:

error[E0412]: cannot find type `T` in this scope
 --> src/main.rs:5:28
  |
5 |     fn fun(&self, p: Point<T>);
  |                            ^ not found in this scope

For more information about this error, try `rustc --explain E0412`.

If I use a longer name for the generic parameter, the compiler gives me the correct hint, like this:

error[E0412]: cannot find type `Tt` in this scope
 --> src/main.rs:5:28
  |
5 |     fn fun(&self, p: Point<Tt>);
  |                            ^^ not found in this scope
  |
help: you might be missing a type parameter
  |
4 | pub trait MyTrait1<Tt> {
  |                   ++++

For more information about this error, try `rustc --explain E0412`.

Other cases

No response

Anything else?

I am using the 1.73.0 Stable channel and it can be reproduced on the nightly (2023-11-07) version as well.

Reproduce the diagnostic with the supplied Rust code on stable or nightly, then compare the suggestions for generic names A, T, and Tt. Done means the A case suggests adding a missing type parameter rather than an unrelated enum variant, while the other reported behaviors remain correct.