syntax_data: {"ast_node_type":"variable","tokens":[{"end":50,"kind":"keyword","start":0,"text":"if"}]}
source_snippet:         if let Some(&s) = self.map.get(&expr_id) {
context_before:         // Check for a designated rvalue scope.
context_after:             debug!("temporary_scope({expr_id:?}) = {s:?} [custom]");