syntax_data: {"ast_node_type":"variable","tokens":[{"end":37,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                 let has_match_guard =
context_before:                 let arm = &self.thir[arm];
context_after:                     if arm.guard.is_some() { HasMatchGuard::Yes } else { HasMatchGuard::No };