Vscode-rust: Duplicated completion entries

Ok, so it seems like the problem in RLS itself. What I understood from description - it uses racer for providing completions. Tried to invoke racer manually. Here's the result:

λ racer complete 3 16 src/main.rs | rg collect
MATCH collect,1476,7,/Users/rpeshkov/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/src/libstd/../libcore/iter/iterator.rs,Function,fn collect<B: FromIterator<Self::Item>>(self) -> B where Self: Sized

So, collect occurs only once in racer's result.

Also, launched LSP inspector from Microsoft to check what language server sends to VSCode and found there 3 occurrences of collect function and other functions as well. Log file:
rust.log.

Didn't manage to setup debuggable rls environment. I'm noob in rust. Hope to have success tomorrow :)

Ok, figured out the problem. Prize goes to racer. I've tested racer completion while I had 2.0 version. RLS is built against 2.1 version. When I checked what happens when I invoke racer complete 3 16 src/main.rs on racer 2.1 - it returns me duplicated entries. It happens because before deduplication of matches, matches are not sorted and dedup_by function removes only consecutive elements.

Made a fix for this behaviour in Racer and opened PR https://github.com/racer-rust/racer/pull/1021

Fixed in https://github.com/rust-lang/rls/pull/1402, should be available in the newest nightly toolchain in 1-2 days.

Closing this as fixed (remember that it's available since Rust 1.35)

@Xanewok I guess this problem continues.

$ racer complete 16 9 src/main.rs
PREFIX 289,289,
MATCH username,2,4,src/main.rs,StructField,String
MATCH email,3,4,src/main.rs,StructField,String
MATCH sign_in_count,4,4,src/main.rs,StructField,u64
MATCH active,5,4,src/main.rs,StructField,bool
END

However, in VS Code, it looks like this:

Please let me know if you need any other debugging information.