//

// . if on an identifier, highlights all references to that identifier in the current file

// .. additionally, if the identifier is a trait in a where clause, type parameter trait bound or use item, highlights all references to that trait's assoc items in the corresponding scope

// . if on a `return` or `fn` keyword, `?` character or `->` return type arrow, highlights all exit points for that context

// . if on a `break`, `loop`, `while` or `for` token, highlights all break points for that loop or block context

// . if on a `move` or `|` token that belongs to a closure, highlights all captures of the closure.