diff --git a/io_surface.rc b/io_surface.rc
index b4198c8..ce39401 100644
--- a/io_surface.rc
+++ b/io_surface.rc
@@ -22,7 +22,7 @@ use cf::string::{CFString, CFStringRef};
 struct __IOSurface { private: () }
 pub type IOSurfaceRef = *__IOSurface;
 
-impl IOSurfaceRef : AbstractCFTypeRef {
+impl AbstractCFTypeRef for IOSurfaceRef {
     pure fn as_type_ref(&self) -> CFTypeRef { *self as CFTypeRef }
 
     static pure fn type_id() -> CFTypeID {
@@ -54,7 +54,7 @@ pub fn lookup(csid: IOSurfaceID) -> IOSurface {
     }
 }
 
-pub impl IOSurface : IOSurfaceMethods {
+pub impl IOSurfaceMethods for IOSurface {
     fn get_id(&self) -> IOSurfaceID {
         unsafe {
             IOSurfaceGetID(self.obj)