str_to_string does not trigger inside a map function

[xtqqczze]

Summary

If you try to use ToString::to_string in a map function on an option, the lint does not trigger.

Lint Name

str_to_string

Reproducer

I tried this code:

pub fn m1(x: Option<&str>) -> Option<String> {
    x.map(ToString::to_string)
}

https://godbolt.org/z/6f8zz67ac

I expected to see this happen:

warning: `to_string()` called on a `&str`

Instead, this happened:

Lint did not trigger

Version

[nyurik]

fixed in #16512