syntax_data: {"ast_node_type":"other","tokens":[{"end":31,"kind":"keyword","start":0,"text":"PatKind::Leaf"}]}
source_snippet:                 PatKind::Leaf {
context_before:                 assert!(!def.is_union()); // Valtree construction would never succeed for unions.
context_after:                     subpatterns: self.field_pats(cv.unwrap_branch().iter().copied().zip(