Intellij-rust: Smart autocompletion not working when nesting several `for` loops.

[joslopgar]

Environment

• IntelliJ Rust plugin version: 0.2.125.3191-201
• Rust toolchain version: 1.44.1
• IDE name and version: CLion 2020.1.2
• Operating system: Windows 10

Problem description

Smart autocompletion not working when nesting several for loops. See below to reproduce issue.

Steps to reproduce

1.) Create a new fresh project in CLion:
cargo new <project-name>

2.) Create a function which contains several nested for loops:

fn process(string: String) -> HashMap<String, Vec<String>> {
    for line in string.lines() {
        for sentence in line.split_terminator('.') {
            for word in sentence.trim().split_whitespace() {
                if word.chars().nth(0).unwrap().is_uppercase() {
                    todo!()
                }
            }
        }
    }
    todo!()
}

3.) Realize that type hinting and smart code completion/suggestion works only inside the first for-loop. For the second and third for-loops, they won't work (See images below).

[Undin]

@joslopgar thanks for the report!
Actually, it's not related to nested loops. Reason of completion absence is fail of type inference for line.split_terminator('.') expression. Try to enable new macro expansion engine (see #3628 for details). It should solve your issue.

[joslopgar]

Thank you for your answer @Undin ! I'm glad this is a known issue, I imagine it's been researched by now.
I tried enabling the new macro expansion engine and it worked!

Should I close the issue then? (This is my time reporting a bug, and I don't know how to proceed).

[Undin]

I tried enabling the new macro expansion engine and it worked!

Glad to hear it!

Should I close the issue then?

No. We will close all issues that are fixed by new macro expansion engine (like this one) after it becomes default option (I hope quite soon)