Please lint on `a.eq(b.into())` if `a.eq(b)` would work

In the course of investigating crater breakage, I discovered many instances of a pattern that reduces to this:

fn main() {
    let s = String::from("hello");
    assert!(s.eq("hello".into()));
}

This compiles, presumably because "hello".into() has only one possible impl that would work. It breaks if another From impl is brought into scope. For instance, cargo add bstr and add use bstr as _; to the top of that example, and it breaks.

Could we lint against this?

cc @estebank; this is in the same spirit as https://github.com/rust-lang/rust/pull/129249/ .

Start with the provided fn main example and reproduce the behavior, including adding bstr and use bstr as _;. Read the linked PR for the intended linting precedent. Done means the problematic form is diagnosed while the direct a.eq(b) form remains accepted, with regression coverage for the example.