[BUG] Const generics broken when inside struct

[utkarshgupta137]

Versions:

rust-analyzer version: 2023-05-15 & Nightly

rustc version: 1.69.0

relevant settings: https://github.com/utkarshgupta137/nvim-lazy/blob/main/lua/lvim/lsp/settings/rust_analyzer.lua

Minimal reproduction:

pub const ONE: usize = 1;

pub struct Inner<const P: usize>();

pub struct Outer {
    pub inner: Inner<ONE>,
}

fn main() {
    _ = Outer {
        inner: Inner::<1>(), // Error: expected Inner<ONE>, found Inner<1> | rust-analyzer (type-mismatch) [11, 16]
    };
}

Diagnosis:

The bug doesn't exist in the 2023-05-08 release.
This PR included in the 2023-05-15 release seems relevant: #14727

[utkarshgupta137]

cc: @HKalbasi

[HKalbasi]

@utkarshgupta137 can you please check if this issue is actually fixed on the master? The stats on webrender doesn't go back to pre #14727 state, but it might be unrelated to this issue.

[utkarshgupta137]

Will do it once a nightly is released.

[lnicola]

Nightly ETA 30 minutes

[utkarshgupta137]

Yes, my issue is resolved now. Will update in case I see it someplace else.
(Yes, I did re-enable the type-mistmatch diagnostic)

[utkarshgupta137]

Welp, it is still occurring in other places. I'll try to share a minimum reproduction.

[utkarshgupta137]

I've found a much nastier bug that completely breaks RA for the files containing Fn(<type alias>) -> <any>.
The same doesn't happen if I do Fn(<any>) -> <type alias>.
The issue can be resolved if you substitute the type alias.

Example:

pub const ONE: usize = 1;

pub type MyInner = Inner<ONE>;

pub struct Inner<const P: usize>();

pub struct Outer {
    pub inner: Inner<ONE>,
}

impl Outer {
    fn map<F>(&self, func: F) -> bool
    where
        F: Fn(&MyInner) -> bool,
    {
        func(&self.inner)
    }
}

fn main() {
    _ = Outer {
        inner: Inner::<1>(),
    };
}

[utkarshgupta137]

@bors reopen

[utkarshgupta137]

@HKalbasi I can't reopen this issue, do you want me to create a new one?
I think it might be a good idea to revert the relevant change until the ramifications are completely understood.

I'd be happy to test any builds you can provide through our 65K line codebase.