{"ast_node_type":"other","tokens":[{"end":51,"kind":"keyword","start":0,"text":"(xform_self_ty,"}]}
                    (xform_self_ty, xform_ret_ty) =
                    let impl_ty = self.tcx.type_of(impl_def_id).instantiate(self.tcx, impl_args);
                        self.xform_self_ty(probe.item, impl_ty, impl_args);