{"ast_node_type":"other","tokens":[{"end":66,"kind":"keyword","start":0,"text":"match"}]}
                        match (self_ty.kind(), unsize_ty.kind()) {
                        debug!("coerce_unsized: ambiguous unsize case for {:?}", trait_pred);
                            (&ty::Infer(ty::TyVar(v)), ty::Dynamic(..))