{"ast_node_type":"other","tokens":[{"end":35,"kind":"keyword","start":0,"text":"hir_id:"}]}
            hir_id: self.next_id(),
        let output = self.arena.alloc(hir::Ty {
            kind: hir::TyKind::InferDelegation(sig_id, hir::InferDelegationKind::Output),