syntax_data: {"ast_node_type":"other","tokens":[{"end":97,"kind":"keyword","start":0,"text":"assert!(!def.is_union());"}]}
source_snippet:                 assert!(!def.is_union()); // Valtree construction would never succeed for unions.
context_before:             ty::Adt(def, args) => {
context_after:                 PatKind::Leaf {