diff --git a/src/liballoc/benches/string.rs b/src/liballoc/benches/string.rs
index 599c8b1682851..5c95160ba2d14 100644
--- a/src/liballoc/benches/string.rs
+++ b/src/liballoc/benches/string.rs
@@ -1,5 +1,5 @@
 use std::iter::repeat;
-use test::Bencher;
+use test::{black_box, Bencher};
 
 #[bench]
 fn bench_with_capacity(b: &mut Bencher) {