syntax_data: {"ast_node_type":"variable","tokens":[{"end":67,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                             let span = this.thir.exprs[guard].span;
context_before:                         if let Some(guard) = arm.guard {
context_after:                             this.tcx.dcx().emit_fatal(LoopMatchArmWithGuard { span })