syntax_data: {"ast_node_type":"other","tokens":[{"end":60,"kind":"keyword","start":0,"text":"debug_assert_eq!(sized_candidates.next(),"}]}
source_snippet:             debug_assert_eq!(sized_candidates.next(), None);
context_before:             // as they would otherwise overlap.
context_after:             // Only prefer the built-in `Sized` candidate if its nested goals are certain.