Completion issue: no method proposed sometimes (e.g. in the crate rayon)

Environment

• IntelliJ Rust plugin version: 0.2.106.2135-192
• Rust toolchain version: stable-x86_64-pc-windows-gnu rustc 1.38.0 (625451e37 2019-09-23)
• IDE name and version: CLion 2019.2.3
• Operating system: Windows 10 Pro x64 1906

Problem description

The autocompletion sometimes does not yield any result. This example demonstrates a concrete scenario using the crate rayon. The function par_iter() does not propose any suggestion, while the code is working. The screenshot below details the issue:

Steps to reproduce

Clone https://[e-mail]/ZenLulz/rust-no-autocompletion-rayon.git. Open the project in the environment defined above. Write a dot (.) after the par_iter() function, in main.rs. Notice that no autocompletion is given.

Sample code:

use rayon::prelude::*;
fn main() {
    let v = vec![1,2,3];
    let x = v.par_iter()./*caret*/ // no completion for `map`
}

[Alfred-Mountfield]

This problem also affects other parts of intellisense, any of the contents of the closures within the operators like map, for_each, etc. after the par_iter aren’t picked up, meaning refactoring misses them, and things like ctrl+click fail to find usages of functions.

[AndreKR]

@cgburgess The first step would be to set up the plugin for development, as described in CONTRIBUTING.md. Check out ARCHITECTURE.md as well.

The next step I guess would be poking around with the debugger, seeing how normally types are represented and then checking what the rayon types are missing.