diff --git a/library/std/src/sys/stdio/vexos.rs b/library/std/src/sys/stdio/vexos.rs
index 1f2251c6421d8..9a391feb7a8a1 100644
--- a/library/std/src/sys/stdio/vexos.rs
+++ b/library/std/src/sys/stdio/vexos.rs
@@ -13,7 +13,7 @@ impl Stdin {
 }
 
 impl io::Read for Stdin {
-    fn read(&mut self, mut buf: &mut [u8]) -> io::Result<usize> {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
         let mut count = 0;
 
         for out_byte in buf.iter_mut() {