Stop dereferencing msg_send!'s first argument

CHANGELOG.md

@@ -1,3 +1,12 @@
+## Unreleased
+
+### Changed
+
+* `msg_send!` no longer dereferences it's first argument, which would invoke
+  undefined behaviour when called with a null pointer. So if you were passing
+  `objc_id::Id` or similar directly, you now have to manually dereference it
+  like this: `msg_send![&*obj, ...]`.
+
 ## 0.2.7
 
 ### Fixed

src/declare.rs

@@ -322,8 +322,8 @@ mod tests {
         // Registering the custom class is in test_utils
         let obj = test_utils::custom_object();
         unsafe {
-            let _: () = msg_send![obj, setFoo:13u32];
-            let result: u32 = msg_send![obj, foo];
+            let _: () = msg_send![&*obj, setFoo:13u32];
+            let result: u32 = msg_send![&*obj, foo];
             assert!(result == 13);
         }
     }

src/macros.rs

@@ -57,8 +57,9 @@ macro_rules! sel {
 /**
 Sends a message to an object.
 
-The first argument can be any type that dereferences to a type that implements
-`Message`, like a reference, pointer, or an `Id`.
+The first argument can be any reference or pointer to a type that implements
+[`Message`].
+
 The syntax is similar to the message syntax in Objective-C.
 Variadic arguments are not currently supported.
 
@@ -81,7 +82,7 @@ macro_rules! msg_send {
     (super($obj:expr, $superclass:expr), $name:ident) => ({
         let sel = $crate::sel!($name);
         let result;
-        match $crate::__send_super_message(&*$obj, $superclass, sel, ()) {
+        match $crate::__send_super_message($obj, $superclass, sel, ()) {
             Err(s) => panic!("{}", s),
             Ok(r) => result = r,
         }
@@ -90,7 +91,7 @@ macro_rules! msg_send {
     (super($obj:expr, $superclass:expr), $($name:ident : $arg:expr)+) => ({
         let sel = $crate::sel!($($name:)+);
         let result;
-        match $crate::__send_super_message(&*$obj, $superclass, sel, ($($arg,)*)) {
+        match $crate::__send_super_message($obj, $superclass, sel, ($($arg,)*)) {
             Err(s) => panic!("{}", s),
             Ok(r) => result = r,
         }
@@ -99,7 +100,7 @@ macro_rules! msg_send {
     ($obj:expr, $name:ident) => ({
         let sel = $crate::sel!($name);
         let result;
-        match $crate::__send_message(&*$obj, sel, ()) {
+        match $crate::__send_message($obj, sel, ()) {
             Err(s) => panic!("{}", s),
             Ok(r) => result = r,
         }
@@ -108,7 +109,7 @@ macro_rules! msg_send {
     ($obj:expr, $($name:ident : $arg:expr)+) => ({
         let sel = $crate::sel!($($name:)+);
         let result;
-        match $crate::__send_message(&*$obj, sel, ($($arg,)*)) {
+        match $crate::__send_message($obj, sel, ($($arg,)*)) {
             Err(s) => panic!("{}", s),
             Ok(r) => result = r,
         }

src/message/mod.rs

@@ -236,8 +236,8 @@ mod tests {
     fn test_send_message() {
         let obj = test_utils::custom_object();
         let result: u32 = unsafe {
-            let _: () = msg_send![obj, setFoo:4u32];
-            msg_send![obj, foo]
+            let _: () = msg_send![&*obj, setFoo:4u32];
+            msg_send![&*obj, foo]
         };
         assert!(result == 4);
     }
@@ -246,7 +246,7 @@ mod tests {
     fn test_send_message_stret() {
         let obj = test_utils::custom_object();
         let result: test_utils::CustomStruct = unsafe {
-            msg_send![obj, customStruct]
+            msg_send![&*obj, customStruct]
         };
         let expected = test_utils::CustomStruct { a: 1, b:2, c: 3, d: 4 };
         assert!(result == expected);
@@ -277,12 +277,12 @@ mod tests {
         let obj = test_utils::custom_subclass_object();
         let superclass = test_utils::custom_class();
         unsafe {
-            let _: () = msg_send![obj, setFoo:4u32];
-            let foo: u32 = msg_send![super(obj, superclass), foo];
+            let _: () = msg_send![&*obj, setFoo:4u32];
+            let foo: u32 = msg_send![super(&*obj, superclass), foo];
             assert!(foo == 4);
 
             // The subclass is overriden to return foo + 2
-            let foo: u32 = msg_send![obj, foo];
+            let foo: u32 = msg_send![&*obj, foo];
             assert!(foo == 6);
         }
     }