diff --git a/src/libcore/run.rs b/src/libcore/run.rs
index ae5c4d19b1c0..0ef22cfc5ec6 100644
--- a/src/libcore/run.rs
+++ b/src/libcore/run.rs
@@ -290,7 +290,7 @@ pub fn start_program(prog: &str, args: &[~str]) -> Program {
 
 fn read_all(rd: io::Reader) -> ~str {
     let buf = io::with_bytes_writer(|wr| {
-        let mut bytes = [mut 0, ..4096];
+        let mut bytes = [0, ..4096];
         while !rd.eof() {
             let nread = rd.read(bytes, bytes.len());
             wr.write(bytes.view(0, nread));
@@ -391,7 +391,7 @@ pub fn readclose(fd: c_int) -> ~str {
         let file = os::fdopen(fd);
         let reader = io::FILE_reader(file, false);
         let buf = io::with_bytes_writer(|writer| {
-            let mut bytes = [mut 0, ..4096];
+            let mut bytes = [0, ..4096];
             while !reader.eof() {
                 let nread = reader.read(bytes, bytes.len());
                 writer.write(bytes.view(0, nread));