Function local_token_sites 

pub fn local_token_sites(
    locals: &[LocalBinding],
    text: &str,
) -> Vec<(Span, bool)>

Every local-binding occurrence in the file — (span, is_definition) — for semantic-token colouring. A token is a definition if it sits on a binding’s def span, else a use if it resolves to a local in scope at that point.