syntax_data: {"ast_node_type":"other","tokens":[{"end":89,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     /// We errored. Signal that in the pattern, so that follow up errors can be silenced.
context_after:     fn mk_err(&self, mut err: Diag<'_>, ty: Ty<'tcx>) -> Box<Pat<'tcx>> {