Function target_resolves 

pub fn target_resolves(document: &Document, target: &ReferenceTarget) -> bool

Does target resolve to at least one declaration anywhere in document? This is the boolean form of [declaration_ranges] — same resolution rules (case-insensitive throughout, citation keys fall back from annotation labels to definition subjects) — used by the opt-in check --references pass to decide whether a reference is dangling. Because it runs over the merged tree it resolves bidirectionally: the target may live in any included fragment or in the master, regardless of where the reference sits.