diff --git a/library/std/src/io/util.rs b/library/std/src/io/util.rs
index 7de37c67abeb..e5e5f29b22d0 100644
--- a/library/std/src/io/util.rs
+++ b/library/std/src/io/util.rs
@@ -82,7 +82,7 @@ impl fmt::Debug for Empty {
 
 impl SizeHint for Empty {
     fn upper_bound(&self) -> Option<usize> {
-       Some(0)
+        Some(0)
     }
 }