{"ast_node_type":"other","tokens":[{"end":98,"kind":"keyword","start":0,"text":"///"}]}
    /// with one element per metavar decl in the matcher. Each element records token trees matched
    /// The matches made against metavar decls so far. On a successful match, this vector ends up
    /// against the relevant metavar by the black box parser. An element will be a `MatchedSeq` if