No autocompletion for inherent_associated_types nightly feature

[Ziothh]

As stated above: my LSP doens't give auto completion for a constant that's typed by the inherent_associated_types feature.
Rustc does compile the program when using the feature.

UPDATE: After some testing I found that this only happens for const values and not variables defined with let (regardless of scope).

Code example

My repo is public so if my code examples aren't clear enough you can always take a look:
Current commit when writing this issue. (Bumping the nightly version from 2023-11-19 to 2023-12-29 has nothing to do with this issue).

// /core/src/hardware/bus.rs
use std::ops;

pub struct MemoryBus(/* ... */);
impl MemoryBus {
    pub type Addr = u16;
    // Also tried replacing MemoryBus::Addr with just plain u16 but didn't work
    // Moving it outside impl and just doing a plain old type does work
    pub type Region = ops::RangeInclusive<MemoryBus::Addr>; 
}

pub mod regions {
    pub const OAM: MemoryBus::Region = 0xFE00..=0xFE9F
}

// /core/src/io/graphics/objects.rs
use crate::hardware::bus;

mod oam {
    struct ObjectAttributes<'a>(bytes: &'a [u8; 4]);

    impl<'a> ObjectAttributes<'a> {
        pub fn from_bus(&memory_bus:  &bus::MemoryBus) -> [ObjectAttributes; 40] {
             // Function I was working on while encountering this issue.
             bus::regions::OAM./* I'd want my LSP to provide me with auto completion here */
        }
    }
}

Toolchain versions

rust-analyzer

$ rust-analyzer --version --verbose
rust-analyzer 1.77.0-nightly (fb5ed72 2023-12-28)

rustc

$ rustc --version --verbose
rustc 1.77.0-nightly (fb5ed726f 2023-12-28)
binary: rustc
commit-hash: fb5ed726f72c6d16c788517c60ec00d4564b9348
commit-date: 2023-12-28
host: x86_64-unknown-linux-gnu
release: 1.77.0-nightly
LLVM version: 17.0.6

Rust feature tracking issue

rust-lang/rust#8995

[Veykril]

The feature is not supported at all in rust-analyzer right now~~, and iirc to implement it we need the new trait solver (or chalk support for it)~~ actually that was assoc type default, unsure about this feature

[Ziothh]

Hey @Veykril, thanks for the quick response.

Are there any relevant issues you could forward me to so I can keep up to date with progress being made on that trait solver you mentioned and/or chalk?

Should I go ahead and close this issue or do you want to keep it open until the feature is supported?

[Veykril]

We can keep this open I don't think we have an issue tracking this feature here yet.

[flodiebold]

actually that was assoc type default, unsure about this feature

Yeah, I feel like this shouldn't be particularly hard to support -- there's really not much difference between

impl Foo {
    type Bar = u32;
}

and

type FooBar = u32;

, is there?

[Ziothh]

Just to be clear: Foo::Bar seems to be supported by rust-analyzer.

It just doesn't resolve (for auto completion & type inference) when a const BAR: Foo::Bar is used somewhere.
It does complain if I assign the wrong value to BAR when it's declared.