Allow any receiver in ClassBuilder::add_method

Author: madsmtm

objc2-foundation/examples/custom_class.rs

@@ -43,20 +43,18 @@ impl MYObject {
             decl.add_ivar::<u32>("_number");
 
             // Add ObjC methods for getting and setting the number
-            extern "C" fn my_object_set_number(this: &mut Object, _cmd: Sel, number: u32) {
-                unsafe {
-                    this.set_ivar("_number", number);
-                }
+            extern "C" fn my_object_set_number(this: &mut MYObject, _cmd: Sel, number: u32) {
+                this.set_number(number);
             }
 
-            extern "C" fn my_object_get_number(this: &Object, _cmd: Sel) -> u32 {
-                unsafe { *this.ivar("_number") }
+            extern "C" fn my_object_get_number(this: &MYObject, _cmd: Sel) -> u32 {
+                this.number()
             }
 
             unsafe {
-                let set_number: extern "C" fn(&mut Object, Sel, u32) = my_object_set_number;
+                let set_number: extern "C" fn(&mut MYObject, Sel, u32) = my_object_set_number;
                 decl.add_method(sel!(setNumber:), set_number);
-                let get_number: extern "C" fn(&Object, Sel) -> u32 = my_object_get_number;
+                let get_number: extern "C" fn(&MYObject, Sel) -> u32 = my_object_get_number;
                 decl.add_method(sel!(number), get_number);
             }
 

objc2/CHANGELOG.md

@@ -34,6 +34,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
   let obj: *mut Object = unsafe { msg_send![class!(NSObject), new] };
   let obj = unsafe { Id::new(obj) }.expect("Failed to allocate object.");
   ```
+* Allow specifying any receiver `T: Message` for methods added with
+  `ClassBuilder::add_method`.
 
 ### Fixed
 * Properly sealed the `MessageArguments` trait (it already had a hidden

objc2/src/declare.rs

@@ -195,9 +195,10 @@ impl ClassDecl {
     ///
     /// The caller must ensure that the types match those that are expected
     /// when the method is invoked from Objective-C.
-    pub unsafe fn add_method<F>(&mut self, sel: Sel, func: F)
+    pub unsafe fn add_method<T, F>(&mut self, sel: Sel, func: F)
     where
-        F: MethodImplementation<Callee = Object>,
+        T: Message + ?Sized, // TODO: Disallow `Class`
+        F: MethodImplementation<Callee = T>,
     {
         let encs = F::Args::ENCODINGS;
         let sel_args = count_args(sel);