syntax_data: {"ast_node_type":"other","tokens":[{"end":99,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:         // Report if the pattern is unreachable, which can only occur when the type is uninhabited.
context_before:         let (cx, report) = self.analyze_binding(pat, Refutable, scrut)?;
context_after:         report_arm_reachability(&cx, &report, false);