diff --git a/cocoa-foundation/src/foundation.rs b/cocoa-foundation/src/foundation.rs
index c935d8e9..022b0e88 100644
--- a/cocoa-foundation/src/foundation.rs
+++ b/cocoa-foundation/src/foundation.rs
@@ -240,7 +240,8 @@ impl NSProcessInfo for id {
     }
 
     unsafe fn isOperatingSystemAtLeastVersion(self, version: NSOperatingSystemVersion) -> bool {
-        msg_send![self, isOperatingSystemAtLeastVersion: version]
+        let res: BOOL = msg_send![self, isOperatingSystemAtLeastVersion: version];
+        res != NO
     }
 }
 
@@ -657,9 +658,9 @@ impl NSString for id {
 
     unsafe fn init_str(self, string: &str) -> id {
         msg_send![self,
-                  initWithBytes:string.as_ptr()
+                  initWithBytes:string.as_ptr() as *const c_void
                       length:string.len()
-                      encoding:UTF8_ENCODING as id]
+                      encoding:UTF8_ENCODING]
     }
 
     unsafe fn len(self) -> usize {
diff --git a/cocoa/src/appkit.rs b/cocoa/src/appkit.rs
index 0d9abc65..4a6747d4 100644
--- a/cocoa/src/appkit.rs
+++ b/cocoa/src/appkit.rs
@@ -2402,7 +2402,7 @@ impl NSOpenGLPixelFormat for id {
     // Creating an NSOpenGLPixelFormat Object
 
     unsafe fn initWithAttributes_(self, attributes: &[u32]) -> id {
-        msg_send![self, initWithAttributes: attributes]
+        msg_send![self, initWithAttributes:attributes.as_ptr()]
     }
 
     // Managing the Pixel Format
diff --git a/cocoa/src/quartzcore.rs b/cocoa/src/quartzcore.rs
index 65bfa68d..c96d8651 100644
--- a/cocoa/src/quartzcore.rs
+++ b/cocoa/src/quartzcore.rs
@@ -946,12 +946,12 @@ impl CALayer {
 
     #[inline]
     pub fn actions(&self) -> CFDictionary<CFStringRef, CFTypeRef> {
-        unsafe { msg_send![self.id(), actions] }
+        unsafe { CFDictionary::wrap_under_get_rule(msg_send![self.id(), actions]) }
     }
 
     #[inline]
     pub unsafe fn set_actions(&self, actions: CFDictionary<CFStringRef, CFTypeRef>) {
-        msg_send![self.id(), setActions: actions]
+        msg_send![self.id(), setActions: actions.as_concrete_TypeRef()]
     }
 
     // TODO(pcwalton): Wrap `CAAnimation`.
@@ -1362,6 +1362,7 @@ impl CARenderer {
 // really just a module.
 pub mod transaction {
     use block::{Block, ConcreteBlock, IntoConcreteBlock, RcBlock};
+    use core_foundation::base::TCFType;
     use core_foundation::date::CFTimeInterval;
     use core_foundation::string::CFString;
     use objc::{class, msg_send, sel, sel_impl};
@@ -1454,7 +1455,7 @@ pub mod transaction {
     pub fn value_for_key(key: &str) -> id {
         unsafe {
             let key: CFString = CFString::from(key);
-            msg_send![class!(CATransaction), valueForKey: key]
+            msg_send![class!(CATransaction), valueForKey: key.as_concrete_TypeRef()]
         }
     }
 
@@ -1462,7 +1463,7 @@ pub mod transaction {
     pub fn set_value_for_key(value: id, key: &str) {
         unsafe {
             let key: CFString = CFString::from(key);
-            msg_send![class!(CATransaction), setValue:value forKey:key]
+            msg_send![class!(CATransaction), setValue: value forKey: key.as_concrete_TypeRef()]
         }
     }
 }
diff --git a/core-text/src/font.rs b/core-text/src/font.rs
index f5deb644..c1db6b8a 100644
--- a/core-text/src/font.rs
+++ b/core-text/src/font.rs
@@ -244,7 +244,7 @@ pub fn new_ui_font_for_language(
     unsafe {
         let font_ref = CTFontCreateUIFontForLanguage(
             ui_type,
-            size,
+            size as CGFloat,
             language
                 .as_ref()
                 .map(|x| x.as_concrete_TypeRef())