syntax_data: {"ast_node_type":"other","tokens":[{"end":41,"kind":"keyword","start":0,"text":"expanded_consts:"}]}
source_snippet:         expanded_consts: &mut Vec<DefId>,
context_before:         ascriptions: &mut Vec<Ascription<'tcx>>,
context_after:     ) -> Result<Option<PatRangeBoundary<'tcx>>, ErrorGuaranteed> {