{"ast_node_type":"other","tokens":[{"end":76,"kind":"keyword","start":0,"text":"GenericKind::Placeholder(ref"}]}
            GenericKind::Placeholder(ref p) => Ty::new_placeholder(tcx, *p),
            GenericKind::Param(ref p) => p.to_ty(tcx),
            GenericKind::Alias(ref p) => p.to_ty(tcx),