fn check_must_use(cx: &LateContext, def_id: DefId, sp: Span, describe_path: &str) -> bool {
for attr in cx.tcx.get_attrs(def_id).iter() {
if attr.check_name("must_use") {
- let mut msg = format!("unused {}`{}` which must be used",
+ let msg = format!("unused {}`{}` which must be used",
describe_path, cx.tcx.item_path_str(def_id));
let mut err = cx.struct_span_lint(UNUSED_MUST_USE, sp, &msg);
// check for #[must_use = "..."]