`generic_const_exprs` suggestion to add bound interacts poorly with legacy const generics

[asquared31415]

Code

#![allow(incomplete_features)]
#![feature(generic_const_exprs)]

use std::arch::x86_64::*;
fn uwu<const N: i32>() {
    unsafe {
        let a = _mm_setzero_ps();
        let b = _mm_setzero_ps();
        _mm_shuffle_ps(a, b, N + 1);
    }
}

Current output

error: unconstrained generic constant
 --> src/lib.rs:9:30
  |
9 |         _mm_shuffle_ps(a, b, N + 1);
  |                              ^^^^^
  |
  = help: try adding a `where` bound using this expression: `where [(); _mm_shuffle_ps]:`

Desired output

error: unconstrained generic constant
 --> src/lib.rs:9:30
  |
9 |         _mm_shuffle_ps(a, b, N + 1);
  |                              ^^^^^
  |
  = help: try adding a `where` bound using this expression: `where [(); N + 1]:`

Rationale and extra context

No response

Other cases

No response

Anything else?

No response

[IsaiahCoroama]

@rustbot claim

[asquared31415]

@IsaiahCoroama this issue probably doesn't need to be resolved because the generic_const_exprs feature is likely on the way to being removed. I'm uncertain if any equivalents exist for generic_const_args, which would be much more interesting, because those are getting active work.

[IsaiahCoroama]

@asquared31415 Sorry, I already made the fixes before I saw this. If the feature gets dropped, it should be easy to revert my changes (if they end up getting merged, that is).