diff --git a/src/platform_impl/macos/event_loop.rs b/src/platform_impl/macos/event_loop.rs
index f3df1b52..d6d89092 100644
--- a/src/platform_impl/macos/event_loop.rs
+++ b/src/platform_impl/macos/event_loop.rs
@@ -132,7 +132,7 @@ impl<T> Proxy<T> {
             // process user events through the normal OS EventLoop mechanisms.
             let rl = CFRunLoopGetMain();
             let mut context: CFRunLoopSourceContext = mem::zeroed();
-            context.perform = event_loop_proxy_handler;
+            context.perform = Some(event_loop_proxy_handler);
             let source =
                 CFRunLoopSourceCreate(ptr::null_mut(), CFIndex::max_value() - 1, &mut context);
             CFRunLoopAddSource(rl, source, kCFRunLoopCommonModes);
diff --git a/src/platform_impl/macos/observer.rs b/src/platform_impl/macos/observer.rs
index 10e78e0e..edd8e994 100644
--- a/src/platform_impl/macos/observer.rs
+++ b/src/platform_impl/macos/observer.rs
@@ -93,14 +93,14 @@ pub enum CFRunLoopTimerContext {}
 pub struct CFRunLoopSourceContext {
     pub version: CFIndex,
     pub info: *mut c_void,
-    pub retain: extern "C" fn(*const c_void) -> *const c_void,
-    pub release: extern "C" fn(*const c_void),
-    pub copyDescription: extern "C" fn(*const c_void) -> CFStringRef,
-    pub equal: extern "C" fn(*const c_void, *const c_void) -> ffi::Boolean,
-    pub hash: extern "C" fn(*const c_void) -> CFHashCode,
-    pub schedule: extern "C" fn(*mut c_void, CFRunLoopRef, CFRunLoopMode),
-    pub cancel: extern "C" fn(*mut c_void, CFRunLoopRef, CFRunLoopMode),
-    pub perform: extern "C" fn(*mut c_void),
+    pub retain: Option<extern "C" fn(*const c_void) -> *const c_void>,
+    pub release: Option<extern "C" fn(*const c_void)>,
+    pub copyDescription: Option<extern "C" fn(*const c_void) -> CFStringRef>,
+    pub equal: Option<extern "C" fn(*const c_void, *const c_void) -> ffi::Boolean>,
+    pub hash: Option<extern "C" fn(*const c_void) -> CFHashCode>,
+    pub schedule: Option<extern "C" fn(*mut c_void, CFRunLoopRef, CFRunLoopMode)>,
+    pub cancel: Option<extern "C" fn(*mut c_void, CFRunLoopRef, CFRunLoopMode)>,
+    pub perform: Option<extern "C" fn(*mut c_void)>,
 }
 
 // begin is queued with the highest priority to ensure it is processed before other observers