diff --git a/src/libstd/io/mod.rs b/src/libstd/io/mod.rs
index 3de9a068926..bc3791b99d0 100644
--- a/src/libstd/io/mod.rs
+++ b/src/libstd/io/mod.rs
@@ -106,8 +106,9 @@ fn read_to_end<R: Read + ?Sized>(r: &mut R, buf: &mut Vec<u8>) -> Result<usize>
     loop {
         if len == buf.len() {
             if buf.capacity() == buf.len() {
-                // reserve() rounds up our request to the nearest power of two, so after the first
-                // time the capacity is exceeded, we double our capacity at each call to reserve. 
+                // reserve() rounds up our request to the nearest power of two,
+                // so after the first time the capacity is exceeded, we double
+                // our capacity at each call to reserve. 
                 buf.reserve(min_cap_bump);
             }
             let new_area = buf.capacity() - buf.len();