syntax_data: {"ast_node_type":"other","tokens":[{"end":31,"kind":"keyword","start":0,"text":"ty::Adt(def,"}]}
source_snippet:         ty::Adt(def, args) => {
context_before:         ty::Adt(def, _) if def.variants().is_empty() => bug!("unreachable"),
context_after:             let (variant_idx, branches) = if def.is_enum() {