gtk: Relax Class methods trait requirements

So they can be called outside of class_init unless required
in which case we add an explicit Self: ClassStruct requirement

gtk4/src/subclass/cell_area.rs

@@ -930,7 +930,7 @@ unsafe extern "C" fn cell_area_foreach_alloc<T: CellAreaImpl>(
 }
 
 #[allow(clippy::missing_safety_doc)]
-pub unsafe trait CellAreaClassExt: ClassStruct {
+pub unsafe trait CellAreaClassExt {
     #[doc(alias = "gtk_cell_area_class_find_cell_property")]
     fn find_cell_property(&self, property_name: &str) -> Option<ParamSpec> {
         unsafe {
@@ -956,4 +956,4 @@ pub unsafe trait CellAreaClassExt: ClassStruct {
     }
 }
 
-unsafe impl<T: ClassStruct> CellAreaClassExt for T where T::Type: CellAreaImpl {}
+unsafe impl<T: IsA<CellArea> + glib::object::IsClass> CellAreaClassExt for glib::object::Class<T> {}

gtk4/src/subclass/widget.rs

@@ -861,7 +861,7 @@ unsafe extern "C" fn widget_unroot<T: WidgetImpl>(ptr: *mut ffi::GtkWidget) {
 }
 
 #[allow(clippy::missing_safety_doc)]
-pub unsafe trait WidgetClassExt: ClassStruct {
+pub unsafe trait WidgetClassExt {
     #[doc(alias = "gtk_widget_class_set_template")]
     fn set_template_bytes(&mut self, template: &glib::Bytes) {
         unsafe {
@@ -905,6 +905,7 @@ pub unsafe trait WidgetClassExt: ClassStruct {
             + 'static
             + Clone,
         Fut: Future<Output = ()>,
+        Self: ClassStruct,
     {
         self.install_action(
             action_name,
@@ -939,6 +940,7 @@ pub unsafe trait WidgetClassExt: ClassStruct {
     ) where
         F: Fn(&<<Self as ClassStruct>::Type as ObjectSubclass>::Type, &str, Option<&Variant>)
             + 'static,
+        Self: ClassStruct,
     {
         unsafe {
             // We store the activate callbacks in a HashMap<action_name, activate>
@@ -1024,7 +1026,9 @@ pub unsafe trait WidgetClassExt: ClassStruct {
         keyval: gdk::Key,
         mods: gdk::ModifierType,
         callback: F,
-    ) {
+    ) where
+        Self: ClassStruct,
+    {
         let shortcut = crate::Shortcut::new(
             Some(crate::KeyvalTrigger::new(keyval, mods)),
             Some(crate::CallbackAction::new(
@@ -1046,8 +1050,11 @@ pub unsafe trait WidgetClassExt: ClassStruct {
     }
 
     #[doc(alias = "gtk_widget_class_add_binding_signal")]
-    fn add_binding_signal(&mut self, keyval: gdk::Key, mods: gdk::ModifierType, signal_name: &str) {
-        let type_ = <Self::Type as ObjectSubclassType>::type_();
+    fn add_binding_signal(&mut self, keyval: gdk::Key, mods: gdk::ModifierType, signal_name: &str)
+    where
+        Self: ClassStruct,
+    {
+        let type_ = <<Self as ClassStruct>::Type as ObjectSubclassType>::type_();
         assert!(
             SignalId::lookup(signal_name, type_).is_some(),
             "Signal '{signal_name}' doesn't exists for type '{type_}'",
@@ -1103,8 +1110,11 @@ pub unsafe trait WidgetClassExt: ClassStruct {
     }
 
     #[doc(alias = "gtk_widget_class_set_activate_signal_from_name")]
-    fn set_activate_signal_from_name(&mut self, signal_name: &str) {
-        let type_ = <Self::Type as ObjectSubclassType>::type_();
+    fn set_activate_signal_from_name(&mut self, signal_name: &str)
+    where
+        Self: ClassStruct,
+    {
+        let type_ = <<Self as ClassStruct>::Type as ObjectSubclassType>::type_();
         assert!(
             SignalId::lookup(signal_name, type_).is_some(),
             "Signal '{signal_name}' doesn't exists for type '{type_}'",
@@ -1179,12 +1189,13 @@ pub unsafe trait WidgetClassExt: ClassStruct {
         &mut self,
         name: &str,
         internal: bool,
-        offset: field_offset::FieldOffset<Self::Type, TemplateChild<T>>,
+        offset: field_offset::FieldOffset<<Self as ClassStruct>::Type, TemplateChild<T>>,
     ) where
         T: ObjectType + FromGlibPtrNone<*mut <T as ObjectType>::GlibType>,
+        Self: ClassStruct,
     {
         let widget_class = self as *mut _ as *mut ffi::GtkWidgetClass;
-        let private_offset = <Self::Type as ObjectSubclassType>::type_data()
+        let private_offset = <<Self as ClassStruct>::Type as ObjectSubclassType>::type_data()
             .as_ref()
             .impl_offset();
         ffi::gtk_widget_class_bind_template_child_full(
@@ -1195,10 +1206,13 @@ pub unsafe trait WidgetClassExt: ClassStruct {
         )
     }
 
-    fn rust_template_scope(&mut self) -> BuilderRustScope {
+    fn rust_template_scope(&mut self) -> BuilderRustScope
+    where
+        Self: ClassStruct,
+    {
         assert_initialized_main_thread!();
         unsafe {
-            let mut data = <Self::Type as ObjectSubclassType>::type_data();
+            let mut data = <<Self as ClassStruct>::Type as ObjectSubclassType>::type_data();
             let internal = data
                 .as_mut()
                 .class_data_mut::<Internal>(<Self::Type as ObjectSubclassType>::type_())
@@ -1213,7 +1227,7 @@ pub unsafe trait WidgetClassExt: ClassStruct {
     }
 }
 
-unsafe impl<T: ClassStruct> WidgetClassExt for T where T::Type: WidgetImpl {}
+unsafe impl<T: IsA<Widget> + glib::object::IsClass> WidgetClassExt for glib::object::Class<T> {}
 
 #[derive(Debug, PartialEq, Eq)]
 #[repr(transparent)]
@@ -1354,13 +1368,16 @@ pub trait CompositeTemplateCallbacks {
     // rustdoc-stripper-ignore-next
     /// Binds the template callbacks from this type into the default template
     /// scope for `klass`.
-    fn bind_template_callbacks<T: WidgetClassExt>(klass: &mut T) {
+    fn bind_template_callbacks<T: WidgetClassExt + ClassStruct>(klass: &mut T) {
         Self::add_callbacks_to_scope(&klass.rust_template_scope());
     }
     // rustdoc-stripper-ignore-next
     /// Binds the template callbacks from this type into the default template
     /// scope for `klass`, prepending `prefix` to each callback name.
-    fn bind_template_callbacks_prefixed<T: WidgetClassExt>(klass: &mut T, prefix: &str) {
+    fn bind_template_callbacks_prefixed<T: WidgetClassExt + ClassStruct>(
+        klass: &mut T,
+        prefix: &str,
+    ) {
         Self::add_callbacks_to_scope_prefixed(&klass.rust_template_scope(), prefix);
     }
     // rustdoc-stripper-ignore-next