syntax_data: {"ast_node_type":"variable","tokens":[{"end":47,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:     let is_match = match (a.kind(), b.kind()) {
context_before:     // to structural-match types.
context_after:         (ty::ConstKind::Infer(_), _) | (_, ty::ConstKind::Infer(_)) => {