Destructured tuple types not inferred correctly

[yngwi]

When using a query in a Bevy system, destructured tuple values are not correctly infered but shown as {unknown}.

fn test_system(query: Query<(&Position, &Archetype)>) {
    for(pos, arch) in query.iter() {
        println!("{:?} {:?}", pos, arch);
    } 
}

Screenshot where {unknown} is shown:

rust-analyzer version:rust-analyzer version: 0.3.1131-standalone (897a7ec 2022-07-17)

rustc version: rustc 1.64.0-nightly (46b8c23f3 2022-07-01)

[Veykril]

From the looks of it the problem is the Archetype, using it causes us to not longer infer the appropriate methods for WorldQuery. I am a bit confused though, Archetype is clearly not a WorldQuery as it doesn't implement Component, so how does this even compile...?

[Veykril]

Actually your snippet doesn't compile for me at all as Archetype is not a Component, so there is no bug here it seems.

[yngwi]

Sorry I have included a more extensive code example. Position and archetype are both custom component strictly that I defined elsewhere. The code compiles and runs just fine on my system, it's just the type inference that is off. Inference also works if the query includes just a single component instead of a tuple.

[ostwilkens]

I had this issue on w10 after updating vscode, rust-analyzer and rustc.

Reverting to an older nightly toolchain fixed it for me.

rust-toolchain.toml

[toolchain]
channel = "nightly-2022-04-25"

[Veykril]

A reproducible snippet would be welcome, @yngwi is your problem also dependent on the toolchain, that is does the toolchain that was posted here fix the problem for you?

[yngwi]

Hi, I have set the rust toolchain in my project folder as suggested and now see the correct types in VSCode. So this indeed seems to be the cause of the problem.

[Veykril]

Alright, will investigate then, I assume some lang items/unstable traits changed in nightly that are relevant here

[flodiebold]

It might just be proc macro expansion? @yngwi does it still work with the older toolchain if you set rust-analyzer.procMacro.enable to false?

[Veykril]

Oh right, that is most likely it 🤦

[yngwi]

It might just be proc macro expansion? @yngwi does it still work with the older toolchain if you set rust-analyzer.procMacro.enable to false?

After changing this setting it doesn't work any more

[flodiebold]

Yeah, that means this is just caused by proc macro support currently being broken on nightly, i.e. #12600. This should be fixed with the next stable release of rust-analyzer, or you could try the pre-release version.

[yngwi]

Ok, thank you.