diff --git a/src/input/appkit.rs b/src/input/appkit.rs
index 4c8495c9..3139c502 100644
--- a/src/input/appkit.rs
+++ b/src/input/appkit.rs
@@ -6,25 +6,25 @@ use crate::input::{TextFieldDelegate, TEXTFIELD_DELEGATE_PTR};
 use crate::utils::load;
 
 /// Called when editing this text field has ended (e.g. user pressed enter).
-extern "C" fn text_did_end_editing<T: TextFieldDelegate>(this: &mut Object, _: Sel, _info: id) {
+extern "C" fn text_did_end_editing<T: TextFieldDelegate>(this: &Object, _: Sel, _info: id) {
     let view = load::<T>(this, TEXTFIELD_DELEGATE_PTR);
     let s = NSString::retain(unsafe { msg_send![this, stringValue] });
     view.text_did_end_editing(s.to_str());
 }
 
-extern "C" fn text_did_begin_editing<T: TextFieldDelegate>(this: &mut Object, _: Sel, _info: id) {
+extern "C" fn text_did_begin_editing<T: TextFieldDelegate>(this: &Object, _: Sel, _info: id) {
     let view = load::<T>(this, TEXTFIELD_DELEGATE_PTR);
     let s = NSString::retain(unsafe { msg_send![this, stringValue] });
     view.text_did_begin_editing(s.to_str());
 }
 
-extern "C" fn text_did_change<T: TextFieldDelegate>(this: &mut Object, _: Sel, _info: id) {
+extern "C" fn text_did_change<T: TextFieldDelegate>(this: &Object, _: Sel, _info: id) {
     let view = load::<T>(this, TEXTFIELD_DELEGATE_PTR);
     let s = NSString::retain(unsafe { msg_send![this, stringValue] });
     view.text_did_change(s.to_str());
 }
 
-extern "C" fn text_should_begin_editing<T: TextFieldDelegate>(this: &mut Object, _: Sel, _info: id) -> BOOL {
+extern "C" fn text_should_begin_editing<T: TextFieldDelegate>(this: &Object, _: Sel, _info: id) -> BOOL {
     let view = load::<T>(this, TEXTFIELD_DELEGATE_PTR);
     let s = NSString::retain(unsafe { msg_send![this, stringValue] });
 
@@ -34,7 +34,7 @@ extern "C" fn text_should_begin_editing<T: TextFieldDelegate>(this: &mut Object,
     }
 }
 
-extern "C" fn text_should_end_editing<T: TextFieldDelegate>(this: &mut Object, _: Sel, _info: id) -> BOOL {
+extern "C" fn text_should_end_editing<T: TextFieldDelegate>(this: &Object, _: Sel, _info: id) -> BOOL {
     let view = load::<T>(this, TEXTFIELD_DELEGATE_PTR);
     let s = NSString::retain(unsafe { msg_send![this, stringValue] });
     match view.text_should_end_editing(s.to_str()) {
diff --git a/src/input/uikit.rs b/src/input/uikit.rs
index 66a9366f..63065704 100644
--- a/src/input/uikit.rs
+++ b/src/input/uikit.rs
@@ -10,25 +10,25 @@ use crate::input::{TextFieldDelegate, TEXTFIELD_DELEGATE_PTR};
 use crate::utils::load;
 
 /// Called when editing this text field has ended (e.g. user pressed enter).
-extern "C" fn text_did_end_editing<T: TextFieldDelegate>(this: &mut Object, _: Sel, _info: id) {
+extern "C" fn text_did_end_editing<T: TextFieldDelegate>(this: &Object, _: Sel, _info: id) {
     let view = load::<T>(this, TEXTFIELD_DELEGATE_PTR);
     let s = NSString::retain(unsafe { msg_send![this, text] });
     view.text_did_end_editing(s.to_str());
 }
 
-extern "C" fn text_did_begin_editing<T: TextFieldDelegate>(this: &mut Object, _: Sel, _info: id) {
+extern "C" fn text_did_begin_editing<T: TextFieldDelegate>(this: &Object, _: Sel, _info: id) {
     let view = load::<T>(this, TEXTFIELD_DELEGATE_PTR);
     let s = NSString::retain(unsafe { msg_send![this, text] });
     view.text_did_begin_editing(s.to_str());
 }
 
-extern "C" fn text_did_change<T: TextFieldDelegate>(this: &mut Object, _: Sel, _info: id) {
+extern "C" fn text_did_change<T: TextFieldDelegate>(this: &Object, _: Sel, _info: id) {
     let view = load::<T>(this, TEXTFIELD_DELEGATE_PTR);
     let s = NSString::retain(unsafe { msg_send![this, text] });
     view.text_did_change(s.to_str());
 }
 
-extern "C" fn text_should_begin_editing<T: TextFieldDelegate>(this: &mut Object, _: Sel, _info: id) -> BOOL {
+extern "C" fn text_should_begin_editing<T: TextFieldDelegate>(this: &Object, _: Sel, _info: id) -> BOOL {
     let view = load::<T>(this, TEXTFIELD_DELEGATE_PTR);
     let s = NSString::retain(unsafe { msg_send![this, text] });
 
@@ -38,7 +38,7 @@ extern "C" fn text_should_begin_editing<T: TextFieldDelegate>(this: &mut Object,
     }
 }
 
-extern "C" fn text_should_end_editing<T: TextFieldDelegate>(this: &mut Object, _: Sel, _info: id) -> BOOL {
+extern "C" fn text_should_end_editing<T: TextFieldDelegate>(this: &Object, _: Sel, _info: id) -> BOOL {
     let view = load::<T>(this, TEXTFIELD_DELEGATE_PTR);
     let s = NSString::retain(unsafe { msg_send![this, text] });
     match view.text_should_end_editing(s.to_str()) {
diff --git a/src/view/controller/appkit.rs b/src/view/controller/appkit.rs
index 45fb03a4..fe63aa5f 100644
--- a/src/view/controller/appkit.rs
+++ b/src/view/controller/appkit.rs
@@ -11,7 +11,7 @@ use crate::utils::load;
 use crate::view::{ViewDelegate, VIEW_DELEGATE_PTR};
 
 /// Called when the view controller receives a `viewWillAppear` message.
-extern "C" fn will_appear<T: ViewDelegate>(this: &mut Object, _: Sel) {
+extern "C" fn will_appear<T: ViewDelegate>(this: &Object, _: Sel) {
     unsafe {
         let _: () = msg_send![super(this, class!(NSViewController)), viewWillAppear];
     }
@@ -21,7 +21,7 @@ extern "C" fn will_appear<T: ViewDelegate>(this: &mut Object, _: Sel) {
 }
 
 /// Called when the view controller receives a `viewDidAppear` message.
-extern "C" fn did_appear<T: ViewDelegate>(this: &mut Object, _: Sel) {
+extern "C" fn did_appear<T: ViewDelegate>(this: &Object, _: Sel) {
     unsafe {
         let _: () = msg_send![super(this, class!(NSViewController)), viewDidAppear];
     }
@@ -31,7 +31,7 @@ extern "C" fn did_appear<T: ViewDelegate>(this: &mut Object, _: Sel) {
 }
 
 /// Called when the view controller receives a `viewWillDisappear` message.
-extern "C" fn will_disappear<T: ViewDelegate>(this: &mut Object, _: Sel) {
+extern "C" fn will_disappear<T: ViewDelegate>(this: &Object, _: Sel) {
     unsafe {
         let _: () = msg_send![super(this, class!(NSViewController)), viewWillDisappear];
     }
@@ -41,7 +41,7 @@ extern "C" fn will_disappear<T: ViewDelegate>(this: &mut Object, _: Sel) {
 }
 
 /// Called when the view controller receives a `viewDidDisappear` message.
-extern "C" fn did_disappear<T: ViewDelegate>(this: &mut Object, _: Sel) {
+extern "C" fn did_disappear<T: ViewDelegate>(this: &Object, _: Sel) {
     unsafe {
         let _: () = msg_send![super(this, class!(NSViewController)), viewDidDisappear];
     }
diff --git a/src/view/controller/uikit.rs b/src/view/controller/uikit.rs
index 9598dd51..f2526f5c 100644
--- a/src/view/controller/uikit.rs
+++ b/src/view/controller/uikit.rs
@@ -11,7 +11,7 @@ use crate::utils::load;
 use crate::view::{ViewDelegate, VIEW_DELEGATE_PTR};
 
 /// Called when the view controller receives a `viewWillAppear:` message.
-extern "C" fn will_appear<T: ViewDelegate>(this: &mut Object, _: Sel, animated: BOOL) {
+extern "C" fn will_appear<T: ViewDelegate>(this: &Object, _: Sel, animated: BOOL) {
     unsafe {
         let _: () = msg_send![super(this, class!(UIViewController)), viewWillAppear: animated];
     }
@@ -21,7 +21,7 @@ extern "C" fn will_appear<T: ViewDelegate>(this: &mut Object, _: Sel, animated:
 }
 
 /// Called when the view controller receives a `viewDidAppear:` message.
-extern "C" fn did_appear<T: ViewDelegate>(this: &mut Object, _: Sel, animated: BOOL) {
+extern "C" fn did_appear<T: ViewDelegate>(this: &Object, _: Sel, animated: BOOL) {
     unsafe {
         let _: () = msg_send![super(this, class!(UIViewController)), viewDidAppear: animated];
     }
@@ -31,7 +31,7 @@ extern "C" fn did_appear<T: ViewDelegate>(this: &mut Object, _: Sel, animated: B
 }
 
 /// Called when the view controller receives a `viewWillDisappear:` message.
-extern "C" fn will_disappear<T: ViewDelegate>(this: &mut Object, _: Sel, animated: BOOL) {
+extern "C" fn will_disappear<T: ViewDelegate>(this: &Object, _: Sel, animated: BOOL) {
     unsafe {
         let _: () = msg_send![super(this, class!(UIViewController)), viewWillDisappear: animated];
     }
@@ -41,7 +41,7 @@ extern "C" fn will_disappear<T: ViewDelegate>(this: &mut Object, _: Sel, animate
 }
 
 /// Called when the view controller receives a `viewDidDisappear:` message.
-extern "C" fn did_disappear<T: ViewDelegate>(this: &mut Object, _: Sel, animated: BOOL) {
+extern "C" fn did_disappear<T: ViewDelegate>(this: &Object, _: Sel, animated: BOOL) {
     unsafe {
         let _: () = msg_send![super(this, class!(UIViewController)), viewDidDisappear: animated];
     }