Make sure core library from sysroot is handled correctly

[lnicola]

use std::time::Duration;

fn main() {
    Duration::<|>
}

The completion doesn't work in this case. Also, the tooltip says "Failed to exactly resolve the symbol".

[matklad]

most likely #523 or #231 (specifically, glob import support).

[lnicola]

I don't think glob imports are involved, but std::time::Duration is a re-export from core::time. Do you think it's #523?

[matklad]

Yep, looks like it!

[lnicola]

I can't find any extern crate rename, though.

[matklad]

Note that this might be as well a bug in sysroot handling, looks like we don't add core as a dependency of std. The relevant code is here:

https://github.com/rust-analyzer/rust-analyzer/blob/581c97a5c3821e247df372f25cf8c01ed514bdd9/crates/ra_lsp_server/src/project_model/sysroot.rs

and here

https://github.com/rust-analyzer/rust-analyzer/blob/581c97a5c3821e247df372f25cf8c01ed514bdd9/crates/ra_lsp_server/src/server_world.rs#L70-L81

[matklad]

Thinking about this more, this might actually be another issue, reopened with a more specific title.

[lnicola]

Hmm, I tried the obvious thing (add core to STD_DEPS) and now it seems to resolve Duration, but not Duration::from_secs. Completion is still not working.

[flodiebold]

Completion or resolution of associated method calls is simply not implemented yet.

[lnicola]

The associated method limitation seems pretty big, should we open an issue for it?