syntax_data: {"ast_node_type":"variable","tokens":[{"end":84,"kind":"keyword","start":0,"text":"if"}]}
source_snippet:             if let Some(..) = cache.insert((src_state, dst_state), answer.clone()) {
context_before:             let answer = ensure_sufficient_stack(|| self.answer_impl(cache, src_state, dst_state));
context_after:                 panic!("failed to correctly cache transmutability")