syntax_data: {"ast_node_type":"other","tokens":[{"end":52,"kind":"keyword","start":0,"text":"self.provisional_cache.retain(|_,"}]}
source_snippet:         self.provisional_cache.retain(|_, entries| {
context_before:         #[allow(rustc::potential_query_instability)]
context_after:             entries.retain(|entry| entry.heads.highest_cycle_head() != head);