diff --git a/src/sdl2/audio.rs b/src/sdl2/audio.rs
index 8bd8b63c1b6..1ff2e00f626 100644
--- a/src/sdl2/audio.rs
+++ b/src/sdl2/audio.rs
@@ -209,7 +209,7 @@ pub struct AudioSpec<'a > {
 
 extern "C" fn c_audio_callback(userdata: *c_void, stream: *uint8_t, len: c_int) {
     unsafe {
-        let f : &|&mut [u8]| = cast::transmute(userdata);
+        let f : &mut |&mut [u8]| = cast::transmute(userdata);
 
         // FIXME: lifetime error in calling
         //slice::raw::mut_buf_as_slice(stream as *mut u8, len as uint, *f)
diff --git a/src/sdl2/timer.rs b/src/sdl2/timer.rs
index 4bb9a263ed1..62d12bef75a 100644
--- a/src/sdl2/timer.rs
+++ b/src/sdl2/timer.rs
@@ -82,6 +82,6 @@ impl<'a> Drop for Timer<'a> {
 }
 
 extern "C" fn c_timer_callback(_interval: uint32_t, param: *c_void) -> uint32_t {
-    let f : &|| -> uint = unsafe { cast::transmute(param) };
+    let f : &mut || -> uint = unsafe { cast::transmute(param) };
     (*f)() as uint32_t
 }