primitive types in function arguments always underlined

[Jiehong]

Hi,

The following correct programme is weirdly highlighted:

fn main() {
    println!("Sqr(21) = {}", sqr(21));
}

fn sqr(number: i64) -> i64 {
    return number * number;
}

Indeed, number (only on the fn line) and i64 are highlighted in red, and underlined with a little squiggly.
On mouse-over, no information is shown.

When trying to go to the declaration of i64, a Cannot find declaration to go to is shown. Perhaps this is the reason of the highlight?

Screenshot:

[Undin]

This issue was moved to intellij-rust/intellij-rust#2160