Can't find a similar issue, but in this function, the (inlay) hints are behaving weirdly.
As far as I can tell, this is just a visual issue.

rust-analyzer version: 0.3.2539-standalone

rustc version: rustc 1.87.0 (17067e9ac 2025-05-09)

editor or extension: VSCode + rust-lang.rust-analyzer 0.3.2539

code snippet to reproduce:

fn check_tostr_eq<L, R>(left: L, right: R)
where
    L: ExactSizeIterator,
    L::Item: ToString,
    R: ExactSizeIterator,
    R::Item: ToString,
{
    use std::collections::HashSet;

    assert_eq!(left.len(), right.len());

    let l_strings: HashSet<_> = left.map(|s| s.to_string()).collect();
    let r_strings: HashSet<_> = right.map(|s| s.to_string()).collect();

    assert_eq!(l_strings, r_strings);
}

expected result:

• s in the closures should be shown as impl ToString

result:

• s in the closures is shown to be impl ToString + ToString
• s is always shown to be impl L::Item + R::Item, in that order
• e.g., if L::Item in the where is changed to Clone, both s are shown as impl Clone + ToString instead
• even though the hints say s implements ToString, in that example the s.to_string() is correctly identified to be erroneous by other checks
• the names of the closure params don't seem to make any difference