feature(const_trait_impl) is treated as syntax error

[andre-richter]

Hi,

experimental feature const_trait_impl is treated as a syntax error by rust-analyzer. For example, on nightly, the following compiles, but rust-analyzer would complain about the impl const and even erase the const on saving.

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

struct X(u32);

impl const core::ops::Add<u32> for X {
    type Output = u32;
    
    fn add(self, other: u32) -> u32 {
        self.0 + other
    }
}

fn main(){
    let y = X(2);

    println!("{}", y + 1u32);
}

[Veykril]

impl const parsing isn't implemented yet.

and even erase the const on saving.

This shouldn't be caused by RA, at least it seems suprising to me. I wonder if this is rustfmt eating that up for some reason, assuming you have format on save enabled 🤔
That seems to be a rustfmt issue

[flodiebold]

That seems to be a rustfmt issue

Yeah, it's reproducible on playground as well.

[andre-richter]

Ah yeah, sorry for getting that part wrong.

[andre-richter]

Raised rust-lang/rustfmt#4650 for the rustfmt part.