syntax_data: {"ast_node_type":"other","tokens":[{"end":75,"kind":"keyword","start":0,"text":"assert_matches!(variant.variants,"}]}
source_snippet:                 assert_matches!(variant.variants, Variants::Single { .. });
context_before:                 // No nested "multiple".
context_after:                 // Variants should have the same or a smaller size as the full thing,