syntax_data: {"ast_node_type":"impl","tokens":[{"end":73,"kind":"keyword","start":0,"text":"from_entry:"}]}
source_snippet:         from_entry: impl FnOnce(&CanonicalParamEnvCacheEntry<Self>) -> R,
context_before:         f: impl FnOnce() -> CanonicalParamEnvCacheEntry<Self>,
context_after:     ) -> R;