diff --git a/src/libstd/run.rs b/src/libstd/run.rs
index b8e08ea53d4..b204cf6cfb0 100644
--- a/src/libstd/run.rs
+++ b/src/libstd/run.rs
@@ -741,7 +741,7 @@ fn with_envp<T>(env: Option<&[(~str, ~str)]>, cb: &fn(*mut c_void) -> T) -> T {
         let mut blk = ~[];
         for es.each |&(k, v)| {
             let kv = fmt!("%s=%s", k, v);
-            blk.push_all(kv.as_bytes_consume_with_nul());
+            blk.push_all(kv.as_bytes_with_null_consume());
         }
         blk.push(0);
         vec::as_imm_buf(blk, |p, _len|