Ambiguous error reporting when trying to infer const generic type

[Joeyh021]

Given the following code: https://play.rust-lang.org/?version=nightly&mode=debug&edition=2021&gist=659888b8e5f59352118b3c7b39187f29

#![feature(adt_const_params)]
#![feature(generic_const_exprs)]
#![feature(generic_arg_infer)]

#[derive(PartialEq, Eq)]
#[allow(dead_code)]
enum Colour {
    R,
    G,
    B,
    W,
}

struct Led<const C: Colour> {}

impl<const C: Colour> Led<C> {
    pub fn new() -> Led<{ Colour::W }> {
        Led::<{ Colour::W }> {}
    }
}

fn main() {
    let l = Led::<_>::new();
}

The current output is:

error[E0284]: type annotations needed: cannot satisfy `the constant `Led::<{_: Colour}>::new::{constant#0}` can be evaluated`
  --> src\main.rs:24:13
   |
24 |     let l = Led::<_>::new();
   |             ^^^^^^^^^^^^^ cannot satisfy `the constant `Led::<{_: Colour}>::new::{constant#0}` can be evaluated`
   |
note: required by a bound in `Led::<C>::new`
  --> src\main.rs:18:25
   |
18 |     pub fn new() -> Led<{ Colour::Off }> {
   |                         ^^^^^^^^^^^^^^^ required by this bound in `Led::<C>::new`

For more information about this error, try `rustc --explain E0284`.

The error message being cannot satisfy 'the constant 'Led::<{_: Colour}>::new::{constant#0}' can be evaluated' doesn't explain the error at all, and is confusing in the way it is reported. I'm not entirely sure what is going on internally, but getting the compiler to emit a proper error message explaining that the const generic type cannot be inferred would be useful.

[lcnr]

same issue as #92186