syntax_data: {"ast_node_type":"variable","tokens":[{"end":38,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:             let hir_id = arm.arm_data;
context_before:         if let Usefulness::Redundant(explanation) = is_useful {
context_after:             let arm_span = cx.tcx.hir_span(hir_id);