syntax_data: {"ast_node_type":"other","tokens":[{"end":93,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     /// or one of the parent generics. Returns the `DefId` of the parameter definition if so.
context_before:     /// Given some item `binding_item`, check if this region is a generic parameter introduced by it
context_after:     pub fn opt_param_def_id(self, tcx: TyCtxt<'tcx>, binding_item: DefId) -> Option<DefId> {