Flyimport completion sometimes won't suggest std::iter::once

[johnw42]

Using VS Code completion, I can't get anything to complete to std::iter::once. When there are no imports and the word before the point is onc or once, the suggestions I get are std::iter::once_with (twice!), FnOnce, and std::lazy::SyncOnceCell. I'm testing using a brand-new crate created with cargo init --lib.

rust-analyzer d15f646 2021-08-30 stable
code 1.58.0 2d23c42a936db1c7b3b06f918cde29561cc47cd6 x64
Extension version: 0.2.727

[lnicola]

Hmm, it does seem to work for me:

It even includes the module, which it probably shouldn't.

[flodiebold]

What rustc version are you using?

[flodiebold]

Oh, I think this is about autoimport completions? I.e. just typing on<|> and getting once (use std::iter::once). I indeed don't see that, even with onc<|>. The autoimport code action works on once though, and 'qualify' is even suggested twice for some reason 😕

[Veykril]

The qualify one gives two options because of the module with the same name(which we currently find when searching for some reason), we fixed that for auto-import but not for qualiy_path it seems, fixed that now #10114

I do see the completion for onc though(typoed in the screenshot but it does work for onc too)

For o and on we don't flyimport the completion as we only apply it for more than 2 characters.

[Veykril]

I'm not sure whether its intentional that we discard the flyimport for an item if its name is fully typed out though, feels like we shouldn't discard it since the import is still of interest.

[johnw42]

I definitely agree with you there. It feels weird having to scroll up and manually add an import when it happens automatically 95% of the time, and I'd much prefer it be automated so the time so I don't have to think about things like how to group the imports to be consistent with the existing style. Would making that and change allow me to do something like expand the suggestions for "iter" and get an option to add an import for "std::iter"? I see a lot of examples where names are qualified by a module name in std, and I wish rust-analyzer made it easier to use that style.

…

On Wed, Sep 1, 2021, 12:59 PM Lukas Wirth ***@***.***> wrote: I'm not sure whether its intentional that we discard the flyimport for an item if its name is fully typed out though, feels like we shouldn't discard it since the import is still of interest. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#10112 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AABRJQ3JLCT3S26RZL4IVXDT72A2RANCNFSM5DG6BYVA> . Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>.

[Veykril]

You can flyimport modules, so (with this bug? fixed) you could type out iter and then get a completion that would add the import for std::iter for you.

Edit: Well it should but it looks like we do not show the iter module for some reason even for just ite, probably due to the limit we set up.

[Veykril]

So this is interesting, depending on your crate graph typing onc will show the completion for std::iter::once, but typing once will not(due to reaching the query limit in this case). The cause for this I believe is https://github.com/rust-analyzer/rust-analyzer/blob/7409880a07803c34590ad162d7854061145c6eae/crates/hir_def/src/import_map.rs#L415
effectively making the order of how we traverse the query results "random", replacing this with FxIndexSet unfortunately effectively causes us to not show std::iter::once at all, which I believe is due to a lot of simd functions matching prior to once.

[Veykril]

I will close this, the limit here might be lifted in the future, it might not. There were a bunch of improvements here though which should make this less likely to run into.