diff --git a/gdk4/src/clipboard.rs b/gdk4/src/clipboard.rs
index 4787e08d819f..49d8be7bef60 100644
--- a/gdk4/src/clipboard.rs
+++ b/gdk4/src/clipboard.rs
@@ -10,14 +10,11 @@ use std::ptr;
 
 impl Clipboard {
     #[doc(alias = "gdk_clipboard_read_async")]
-    pub fn read_async<
-        P: IsA<gio::Cancellable>,
-        Q: FnOnce(Result<(gio::InputStream, GString), glib::Error>) + 'static,
-    >(
+    pub fn read_async<Q: FnOnce(Result<(gio::InputStream, GString), glib::Error>) + 'static>(
         &self,
         mime_types: &[&str],
         io_priority: glib::Priority,
-        cancellable: Option<&P>,
+        cancellable: Option<&impl IsA<gio::Cancellable>>,
         callback: Q,
     ) {
         let user_data: Box<Q> = Box::new(callback);
@@ -89,10 +86,10 @@ impl Clipboard {
     }
 
     #[doc(alias = "gdk_clipboard_store_async")]
-    pub fn store_async<P: IsA<gio::Cancellable>, Q: FnOnce(Result<(), glib::Error>) + 'static>(
+    pub fn store_async<Q: FnOnce(Result<(), glib::Error>) + 'static>(
         &self,
         io_priority: glib::Priority,
-        cancellable: Option<&P>,
+        cancellable: Option<&impl IsA<gio::Cancellable>>,
         callback: Q,
     ) {
         let user_data: Box<Q> = Box::new(callback);
@@ -137,14 +134,11 @@ impl Clipboard {
     }
 
     #[doc(alias = "gdk_clipboard_read_value_async")]
-    pub fn read_value_async<
-        P: IsA<gio::Cancellable>,
-        Q: FnOnce(Result<glib::Value, glib::Error>) + 'static,
-    >(
+    pub fn read_value_async<Q: FnOnce(Result<glib::Value, glib::Error>) + 'static>(
         &self,
         type_: glib::types::Type,
         io_priority: glib::Priority,
-        cancellable: Option<&P>,
+        cancellable: Option<&impl IsA<gio::Cancellable>>,
         callback: Q,
     ) {
         let user_data: Box<Q> = Box::new(callback);
@@ -193,12 +187,9 @@ impl Clipboard {
     }
 
     #[doc(alias = "gdk_clipboard_read_text_async")]
-    pub fn read_text_async<
-        P: IsA<gio::Cancellable>,
-        Q: FnOnce(Result<Option<glib::GString>, glib::Error>) + 'static,
-    >(
+    pub fn read_text_async<Q: FnOnce(Result<Option<glib::GString>, glib::Error>) + 'static>(
         &self,
-        cancellable: Option<&P>,
+        cancellable: Option<&impl IsA<gio::Cancellable>>,
         callback: Q,
     ) {
         let user_data: Box<Q> = Box::new(callback);
@@ -244,12 +235,9 @@ impl Clipboard {
     }
 
     #[doc(alias = "gdk_clipboard_read_texture_async")]
-    pub fn read_texture_async<
-        P: IsA<gio::Cancellable>,
-        Q: FnOnce(Result<Option<Texture>, glib::Error>) + 'static,
-    >(
+    pub fn read_texture_async<Q: FnOnce(Result<Option<Texture>, glib::Error>) + 'static>(
         &self,
-        cancellable: Option<&P>,
+        cancellable: Option<&impl IsA<gio::Cancellable>>,
         callback: Q,
     ) {
         let user_data: Box<Q> = Box::new(callback);
diff --git a/gdk4/src/drop.rs b/gdk4/src/drop.rs
index 7f13d3e5db92..c73163d915e0 100644
--- a/gdk4/src/drop.rs
+++ b/gdk4/src/drop.rs
@@ -11,14 +11,11 @@ use std::ptr;
 
 impl Drop {
     #[doc(alias = "gdk_drop_read_async")]
-    pub fn read_async<
-        P: IsA<gio::Cancellable>,
-        Q: FnOnce(Result<(gio::InputStream, GString), glib::Error>) + 'static,
-    >(
+    pub fn read_async<Q: FnOnce(Result<(gio::InputStream, GString), glib::Error>) + 'static>(
         &self,
         mime_types: &[&str],
         io_priority: glib::Priority,
-        cancellable: Option<&P>,
+        cancellable: Option<&impl IsA<gio::Cancellable>>,
         callback: Q,
     ) {
         let user_data: Box<Q> = Box::new(callback);
@@ -81,14 +78,11 @@ impl Drop {
     }
 
     #[doc(alias = "gdk_drop_read_value_async")]
-    pub fn read_value_async<
-        P: IsA<gio::Cancellable>,
-        Q: FnOnce(Result<glib::Value, glib::Error>) + 'static,
-    >(
+    pub fn read_value_async<Q: FnOnce(Result<glib::Value, glib::Error>) + 'static>(
         &self,
         type_: glib::types::Type,
         io_priority: glib::Priority,
-        cancellable: Option<&P>,
+        cancellable: Option<&impl IsA<gio::Cancellable>>,
         callback: Q,
     ) {
         let user_data: Box<Q> = Box::new(callback);
diff --git a/gdk4/src/event.rs b/gdk4/src/event.rs
index 02ca952efc76..8109c57d8107 100644
--- a/gdk4/src/event.rs
+++ b/gdk4/src/event.rs
@@ -29,7 +29,7 @@ impl Event {
 
     #[doc(alias = "gdk_events_get_angle")]
     #[doc(alias = "get_angle")]
-    pub fn angle<P: AsRef<Event>>(&self, event: P) -> Option<f64> {
+    pub fn angle(&self, event: impl AsRef<Event>) -> Option<f64> {
         skip_assert_initialized!();
         unsafe {
             let mut angle = mem::MaybeUninit::uninit();
@@ -49,7 +49,7 @@ impl Event {
 
     #[doc(alias = "gdk_events_get_center")]
     #[doc(alias = "get_center")]
-    pub fn center<P: AsRef<Event>>(&self, event: P) -> Option<(f64, f64)> {
+    pub fn center(&self, event: impl AsRef<Event>) -> Option<(f64, f64)> {
         skip_assert_initialized!();
         unsafe {
             let mut x = mem::MaybeUninit::uninit();
@@ -72,7 +72,7 @@ impl Event {
 
     #[doc(alias = "gdk_events_get_distance")]
     #[doc(alias = "get_distance")]
-    pub fn distance<P: AsRef<Event>>(&self, event: P) -> Option<f64> {
+    pub fn distance(&self, event: impl AsRef<Event>) -> Option<f64> {
         skip_assert_initialized!();
         unsafe {
             let mut distance = mem::MaybeUninit::uninit();
diff --git a/gdk4/src/functions.rs b/gdk4/src/functions.rs
index e223ff1764a7..f7f248591ccb 100644
--- a/gdk4/src/functions.rs
+++ b/gdk4/src/functions.rs
@@ -32,16 +32,12 @@ pub fn pango_layout_get_clip_region(
 }
 
 #[doc(alias = "gdk_content_deserialize_async")]
-pub fn content_deserialize_async<
-    P: IsA<gio::InputStream>,
-    Q: IsA<gio::Cancellable>,
-    R: FnOnce(Result<glib::Value, glib::Error>) + Send + 'static,
->(
-    stream: &P,
+pub fn content_deserialize_async<R: FnOnce(Result<glib::Value, glib::Error>) + Send + 'static>(
+    stream: &impl IsA<gio::InputStream>,
     mime_type: &str,
     type_: glib::types::Type,
     io_priority: glib::Priority,
-    cancellable: Option<&Q>,
+    cancellable: Option<&impl IsA<gio::Cancellable>>,
     callback: R,
 ) {
     assert_initialized_main_thread!();
@@ -78,8 +74,8 @@ pub fn content_deserialize_async<
     }
 }
 
-pub fn content_deserialize_future<P: IsA<gio::InputStream> + Clone + 'static>(
-    stream: &P,
+pub fn content_deserialize_future(
+    stream: &(impl IsA<gio::InputStream> + Clone + 'static),
     mime_type: &str,
     type_: glib::types::Type,
     io_priority: glib::Priority,
@@ -222,16 +218,12 @@ pub fn content_register_serializer<
 }
 
 #[doc(alias = "gdk_content_serialize_async")]
-pub fn content_serialize_async<
-    P: IsA<gio::OutputStream>,
-    Q: IsA<gio::Cancellable>,
-    R: FnOnce(Result<(), glib::Error>) + Send + 'static,
->(
-    stream: &P,
+pub fn content_serialize_async<R: FnOnce(Result<(), glib::Error>) + Send + 'static>(
+    stream: &impl IsA<gio::OutputStream>,
     mime_type: &str,
     value: &glib::Value,
     io_priority: glib::Priority,
-    cancellable: Option<&Q>,
+    cancellable: Option<&impl IsA<gio::Cancellable>>,
     callback: R,
 ) {
     assert_initialized_main_thread!();
@@ -267,8 +259,8 @@ pub fn content_serialize_async<
     }
 }
 
-pub fn content_serialize_future<P: IsA<gio::OutputStream> + Clone + 'static>(
-    stream: &P,
+pub fn content_serialize_future(
+    stream: &(impl IsA<gio::OutputStream> + Clone + 'static),
     mime_type: &str,
     value: &glib::Value,
     io_priority: glib::Priority,
diff --git a/gtk4/src/builder.rs b/gtk4/src/builder.rs
index 88d0b32e9a70..d230f0ea3749 100644
--- a/gtk4/src/builder.rs
+++ b/gtk4/src/builder.rs
@@ -9,7 +9,7 @@ use std::path::Path;
 impl Builder {
     #[doc(alias = "gtk_builder_new_from_file")]
     #[doc(alias = "new_from_file")]
-    pub fn from_file<T: AsRef<Path>>(file_path: T) -> Self {
+    pub fn from_file(file_path: impl AsRef<Path>) -> Self {
         assert_initialized_main_thread!();
         unsafe {
             from_glib_full(ffi::gtk_builder_new_from_file(
@@ -45,7 +45,7 @@ impl Builder {
     }
 
     #[doc(alias = "gtk_builder_add_from_file")]
-    pub fn add_from_file<T: AsRef<Path>>(&self, file_path: T) -> Result<(), glib::Error> {
+    pub fn add_from_file(&self, file_path: impl AsRef<Path>) -> Result<(), glib::Error> {
         unsafe {
             let mut error = ::std::ptr::null_mut();
             ffi::gtk_builder_add_from_file(
diff --git a/gtk4/src/cell_area.rs b/gtk4/src/cell_area.rs
index fdb528bfbe65..0202e57d023a 100644
--- a/gtk4/src/cell_area.rs
+++ b/gtk4/src/cell_area.rs
@@ -17,51 +17,43 @@ pub trait CellAreaExtManual {
     );
 
     #[doc(alias = "gtk_cell_area_activate_cell")]
-    fn activate_cell<P: IsA<Widget>, Q: IsA<CellRenderer>, R: AsRef<Event>>(
+    fn activate_cell(
         &self,
-        widget: &P,
-        renderer: &Q,
-        event: &R,
+        widget: &impl IsA<Widget>,
+        renderer: &impl IsA<CellRenderer>,
+        event: &impl AsRef<Event>,
         cell_area: &gdk::Rectangle,
         flags: CellRendererState,
     ) -> bool;
 
     #[doc(alias = "gtk_cell_area_event")]
-    fn event<P: IsA<CellAreaContext>, Q: IsA<Widget>, R: AsRef<Event>>(
+    fn event(
         &self,
-        context: &P,
-        widget: &Q,
-        event: &R,
+        context: &impl IsA<CellAreaContext>,
+        widget: &impl IsA<Widget>,
+        event: &impl AsRef<Event>,
         cell_area: &gdk::Rectangle,
         flags: CellRendererState,
     ) -> i32;
 
     #[doc(alias = "gtk_cell_area_cell_get_valist")]
     #[doc(alias = "gtk_cell_area_cell_get_property")]
-    fn cell_get_value<P: IsA<CellRenderer>>(
-        &self,
-        renderer: &P,
-        property_name: &str,
-    ) -> glib::Value;
+    fn cell_get_value(&self, renderer: &impl IsA<CellRenderer>, property_name: &str)
+        -> glib::Value;
 
     // rustdoc-stripper-ignore-next
     /// Similar to [`Self::cell_get_value`] but panics if the value is of a different type.
     #[doc(alias = "gtk_cell_area_cell_get_valist")]
     #[doc(alias = "gtk_cell_area_cell_get_property")]
-    fn cell_get<V: for<'b> FromValue<'b> + 'static, P: IsA<CellRenderer>>(
+    fn cell_get<V: for<'b> FromValue<'b> + 'static>(
         &self,
-        renderer: &P,
+        renderer: &impl IsA<CellRenderer>,
         property_name: &str,
     ) -> V;
 
     #[doc(alias = "gtk_cell_area_cell_set_valist")]
     #[doc(alias = "gtk_cell_area_cell_set_property")]
-    fn cell_set<P: IsA<CellRenderer>>(
-        &self,
-        renderer: &P,
-        property_name: &str,
-        value: &dyn ToValue,
-    );
+    fn cell_set(&self, renderer: &impl IsA<CellRenderer>, property_name: &str, value: &dyn ToValue);
 }
 
 impl<O: IsA<CellArea>> CellAreaExtManual for O {
@@ -75,11 +67,11 @@ impl<O: IsA<CellArea>> CellAreaExtManual for O {
             self.as_ref().cell_set(renderer, property_name, *value);
         });
     }
-    fn activate_cell<P: IsA<Widget>, Q: IsA<CellRenderer>, R: AsRef<Event>>(
+    fn activate_cell(
         &self,
-        widget: &P,
-        renderer: &Q,
-        event: &R,
+        widget: &impl IsA<Widget>,
+        renderer: &impl IsA<CellRenderer>,
+        event: &impl AsRef<Event>,
         cell_area: &gdk::Rectangle,
         flags: CellRendererState,
     ) -> bool {
@@ -95,9 +87,9 @@ impl<O: IsA<CellArea>> CellAreaExtManual for O {
         }
     }
 
-    fn cell_get_value<P: IsA<CellRenderer>>(
+    fn cell_get_value(
         &self,
-        renderer: &P,
+        renderer: &impl IsA<CellRenderer>,
         property_name: &str,
     ) -> glib::Value {
         unsafe {
@@ -121,9 +113,9 @@ impl<O: IsA<CellArea>> CellAreaExtManual for O {
         }
     }
 
-    fn cell_get<V: for<'b> FromValue<'b> + 'static, P: IsA<CellRenderer>>(
+    fn cell_get<V: for<'b> FromValue<'b> + 'static>(
         &self,
-        renderer: &P,
+        renderer: &impl IsA<CellRenderer>,
         property_name: &str,
     ) -> V {
         let value = self.cell_get_value(renderer, property_name);
@@ -132,9 +124,9 @@ impl<O: IsA<CellArea>> CellAreaExtManual for O {
             .expect("Failed to get value of renderer")
     }
 
-    fn cell_set<P: IsA<CellRenderer>>(
+    fn cell_set(
         &self,
-        renderer: &P,
+        renderer: &impl IsA<CellRenderer>,
         property_name: &str,
         value: &dyn ToValue,
     ) {
@@ -165,11 +157,11 @@ impl<O: IsA<CellArea>> CellAreaExtManual for O {
         }
     }
 
-    fn event<P: IsA<CellAreaContext>, Q: IsA<Widget>, R: AsRef<Event>>(
+    fn event(
         &self,
-        context: &P,
-        widget: &Q,
-        event: &R,
+        context: &impl IsA<CellAreaContext>,
+        widget: &impl IsA<Widget>,
+        event: &impl AsRef<Event>,
         cell_area: &gdk::Rectangle,
         flags: CellRendererState,
     ) -> i32 {
diff --git a/gtk4/src/cell_editable.rs b/gtk4/src/cell_editable.rs
index 98a134d95ac8..0a29b6abb887 100644
--- a/gtk4/src/cell_editable.rs
+++ b/gtk4/src/cell_editable.rs
@@ -6,11 +6,11 @@ use glib::IsA;
 
 pub trait CellEditableExtManual {
     #[doc(alias = "gtk_cell_editable_start_editing")]
-    fn start_editing<P: AsRef<gdk::Event>>(&self, event: Option<&P>);
+    fn start_editing(&self, event: Option<&impl AsRef<gdk::Event>>);
 }
 
 impl<O: IsA<CellEditable>> CellEditableExtManual for O {
-    fn start_editing<P: AsRef<gdk::Event>>(&self, event: Option<&P>) {
+    fn start_editing(&self, event: Option<&impl AsRef<gdk::Event>>) {
         unsafe {
             ffi::gtk_cell_editable_start_editing(
                 self.as_ref().to_glib_none().0,
diff --git a/gtk4/src/cell_renderer.rs b/gtk4/src/cell_renderer.rs
index 95154126b5f7..13680d1a8fc5 100644
--- a/gtk4/src/cell_renderer.rs
+++ b/gtk4/src/cell_renderer.rs
@@ -8,10 +8,10 @@ use glib::IsA;
 /// Trait containing manually implemented methods of [`CellRenderer`](crate::CellRenderer).
 pub trait CellRendererExtManual {
     #[doc(alias = "gtk_cell_renderer_activate")]
-    fn activate<Q: IsA<Widget>, R: AsRef<gdk::Event>>(
+    fn activate(
         &self,
-        event: &R,
-        widget: &Q,
+        event: &impl AsRef<gdk::Event>,
+        widget: &impl IsA<Widget>,
         path: &str,
         background_area: &gdk::Rectangle,
         cell_area: &gdk::Rectangle,
@@ -19,10 +19,10 @@ pub trait CellRendererExtManual {
     ) -> bool;
 
     #[doc(alias = "gtk_cell_renderer_start_editing")]
-    fn start_editing<Q: IsA<Widget>, R: AsRef<gdk::Event>>(
+    fn start_editing(
         &self,
-        event: Option<&R>,
-        widget: &Q,
+        event: Option<&impl AsRef<gdk::Event>>,
+        widget: &impl IsA<Widget>,
         path: &str,
         background_area: &gdk::Rectangle,
         cell_area: &gdk::Rectangle,
@@ -31,10 +31,10 @@ pub trait CellRendererExtManual {
 }
 
 impl<O: IsA<CellRenderer>> CellRendererExtManual for O {
-    fn activate<Q: IsA<Widget>, R: AsRef<gdk::Event>>(
+    fn activate(
         &self,
-        event: &R,
-        widget: &Q,
+        event: &impl AsRef<gdk::Event>,
+        widget: &impl IsA<Widget>,
         path: &str,
         background_area: &gdk::Rectangle,
         cell_area: &gdk::Rectangle,
@@ -53,10 +53,10 @@ impl<O: IsA<CellRenderer>> CellRendererExtManual for O {
         }
     }
 
-    fn start_editing<Q: IsA<Widget>, R: AsRef<gdk::Event>>(
+    fn start_editing(
         &self,
-        event: Option<&R>,
-        widget: &Q,
+        event: Option<&impl AsRef<gdk::Event>>,
+        widget: &impl IsA<Widget>,
         path: &str,
         background_area: &gdk::Rectangle,
         cell_area: &gdk::Rectangle,
diff --git a/gtk4/src/closure_expression.rs b/gtk4/src/closure_expression.rs
index 0036ee565eb8..ac535cac5801 100644
--- a/gtk4/src/closure_expression.rs
+++ b/gtk4/src/closure_expression.rs
@@ -32,12 +32,11 @@ impl ClosureExpression {
     }
 
     #[doc(alias = "gtk_closure_expression_new")]
-    pub fn with_callback<F, R>(
-        params: impl IntoIterator<Item = impl AsRef<Expression>>,
-        callback: F,
-    ) -> Self
+    pub fn with_callback<R, F, I, E>(params: I, callback: F) -> Self
     where
         F: Fn(&[Value]) -> R + 'static,
+        I: IntoIterator<Item = E>,
+        E: AsRef<Expression>,
         R: ValueType,
     {
         assert_initialized_main_thread!();
diff --git a/gtk4/src/directory_list.rs b/gtk4/src/directory_list.rs
index 2046c8017950..d0b82cacf391 100644
--- a/gtk4/src/directory_list.rs
+++ b/gtk4/src/directory_list.rs
@@ -73,7 +73,7 @@ impl DirectoryListBuilder {
         self
     }
 
-    pub fn file<P: IsA<gio::File>>(mut self, file: &P) -> Self {
+    pub fn file(mut self, file: &impl IsA<gio::File>) -> Self {
         self.file = Some(file.clone().upcast());
         self
     }
diff --git a/gtk4/src/expression.rs b/gtk4/src/expression.rs
index 9c939c1b2dde..534c35e71b10 100644
--- a/gtk4/src/expression.rs
+++ b/gtk4/src/expression.rs
@@ -52,7 +52,7 @@ impl Expression {
     }
 
     #[doc(alias = "gtk_expression_evaluate")]
-    pub fn evaluate<T: IsA<Object>>(&self, this: Option<&T>) -> Option<Value> {
+    pub fn evaluate(&self, this: Option<&impl IsA<Object>>) -> Option<Value> {
         assert_initialized_main_thread!();
         unsafe {
             let mut value = Value::uninitialized();
diff --git a/gtk4/src/file_chooser_dialog.rs b/gtk4/src/file_chooser_dialog.rs
index 43097fe43898..35f39f1d3b39 100644
--- a/gtk4/src/file_chooser_dialog.rs
+++ b/gtk4/src/file_chooser_dialog.rs
@@ -9,9 +9,9 @@ use std::ptr;
 
 impl FileChooserDialog {
     #[doc(alias = "gtk_file_chooser_dialog_new")]
-    pub fn new<T: IsA<Window>>(
+    pub fn new(
         title: Option<&str>,
-        parent: Option<&T>,
+        parent: Option<&impl IsA<Window>>,
         action: FileChooserAction,
         buttons: &[(&str, ResponseType)],
     ) -> Self {
diff --git a/gtk4/src/im_context.rs b/gtk4/src/im_context.rs
index 46278ca67191..3ca2c4cf279e 100644
--- a/gtk4/src/im_context.rs
+++ b/gtk4/src/im_context.rs
@@ -9,11 +9,11 @@ use glib::IsA;
 #[allow(clippy::upper_case_acronyms)]
 pub trait IMContextExtManual {
     #[doc(alias = "gtk_im_context_filter_keypress")]
-    fn filter_keypress<R: AsRef<gdk::Event>>(&self, event: &R) -> bool;
+    fn filter_keypress(&self, event: &impl AsRef<gdk::Event>) -> bool;
 }
 
 impl<O: IsA<IMContext>> IMContextExtManual for O {
-    fn filter_keypress<R: AsRef<gdk::Event>>(&self, event: &R) -> bool {
+    fn filter_keypress(&self, event: &impl AsRef<gdk::Event>) -> bool {
         unsafe {
             from_glib(ffi::gtk_im_context_filter_keypress(
                 self.as_ref().to_glib_none().0,
diff --git a/gtk4/src/im_context_simple.rs b/gtk4/src/im_context_simple.rs
index 287e9a43acaf..34673cbf2b04 100644
--- a/gtk4/src/im_context_simple.rs
+++ b/gtk4/src/im_context_simple.rs
@@ -6,7 +6,7 @@ use std::path::Path;
 
 impl IMContextSimple {
     #[doc(alias = "gtk_im_context_simple_add_compose_file")]
-    pub fn add_compose_file<P: AsRef<Path>>(&self, compose_file: P) {
+    pub fn add_compose_file(&self, compose_file: impl AsRef<Path>) {
         unsafe {
             let compose_file = compose_file.as_ref();
             ffi::gtk_im_context_simple_add_compose_file(
diff --git a/gtk4/src/map_list_model.rs b/gtk4/src/map_list_model.rs
index 6b47145301bd..14f6a62c2a08 100644
--- a/gtk4/src/map_list_model.rs
+++ b/gtk4/src/map_list_model.rs
@@ -6,7 +6,7 @@ use glib::IsA;
 
 impl MapListModel {
     #[doc(alias = "gtk_map_list_model_new")]
-    pub fn without_map_func<P: IsA<gio::ListModel>>(model: Option<&P>) -> Self {
+    pub fn without_map_func(model: Option<&impl IsA<gio::ListModel>>) -> Self {
         assert_initialized_main_thread!();
         unsafe {
             from_glib_full(ffi::gtk_map_list_model_new(
diff --git a/gtk4/src/message_dialog.rs b/gtk4/src/message_dialog.rs
index 1edcc3157de8..16f5d988c773 100644
--- a/gtk4/src/message_dialog.rs
+++ b/gtk4/src/message_dialog.rs
@@ -9,8 +9,8 @@ use crate::{ButtonsType, DialogFlags, MessageDialog, MessageType, Widget, Window
 
 impl MessageDialog {
     #[doc(alias = "gtk_message_dialog_new")]
-    pub fn new<T: IsA<Window>>(
-        parent: Option<&T>,
+    pub fn new(
+        parent: Option<&impl IsA<Window>>,
         flags: DialogFlags,
         type_: MessageType,
         buttons: ButtonsType,
@@ -34,8 +34,8 @@ impl MessageDialog {
 
     #[doc(alias = "gtk_message_dialog_new_with_markup")]
     #[doc(alias = "new_with_markup")]
-    pub fn with_markup<P: IsA<Window>>(
-        parent: Option<&P>,
+    pub fn with_markup(
+        parent: Option<&impl IsA<Window>>,
         flags: DialogFlags,
         type_: MessageType,
         buttons: ButtonsType,
diff --git a/gtk4/src/notebook.rs b/gtk4/src/notebook.rs
index 30a84d0aad91..8ace1447e214 100644
--- a/gtk4/src/notebook.rs
+++ b/gtk4/src/notebook.rs
@@ -7,10 +7,10 @@ use libc::c_int;
 
 impl Notebook {
     #[doc(alias = "gtk_notebook_append_page")]
-    pub fn append_page<T: IsA<Widget>, U: IsA<Widget>>(
+    pub fn append_page(
         &self,
-        child: &T,
-        tab_label: Option<&U>,
+        child: &impl IsA<Widget>,
+        tab_label: Option<&impl IsA<Widget>>,
     ) -> u32 {
         unsafe {
             let ret = ffi::gtk_notebook_append_page(
@@ -24,17 +24,12 @@ impl Notebook {
     }
 
     #[doc(alias = "gtk_notebook_append_page_menu")]
-    pub fn append_page_menu<T, U, V>(
+    pub fn append_page_menu(
         &self,
-        child: &T,
-        tab_label: Option<&U>,
-        menu_label: Option<&V>,
-    ) -> u32
-    where
-        T: IsA<Widget>,
-        U: IsA<Widget>,
-        V: IsA<Widget>,
-    {
+        child: &impl IsA<Widget>,
+        tab_label: Option<&impl IsA<Widget>>,
+        menu_label: Option<&impl IsA<Widget>>,
+    ) -> u32 {
         unsafe {
             let ret = ffi::gtk_notebook_append_page_menu(
                 self.to_glib_none().0,
@@ -82,11 +77,12 @@ impl Notebook {
     }
 
     #[doc(alias = "gtk_notebook_insert_page")]
-    pub fn insert_page<T, U>(&self, child: &T, tab_label: Option<&U>, position: Option<u32>) -> u32
-    where
-        T: IsA<Widget>,
-        U: IsA<Widget>,
-    {
+    pub fn insert_page(
+        &self,
+        child: &impl IsA<Widget>,
+        tab_label: Option<&impl IsA<Widget>>,
+        position: Option<u32>,
+    ) -> u32 {
         unsafe {
             let ret = ffi::gtk_notebook_insert_page(
                 self.to_glib_none().0,
@@ -100,18 +96,13 @@ impl Notebook {
     }
 
     #[doc(alias = "gtk_notebook_insert_page_menu")]
-    pub fn insert_page_menu<T, U, V>(
+    pub fn insert_page_menu(
         &self,
-        child: &T,
-        tab_label: Option<&U>,
-        menu_label: Option<&V>,
+        child: &impl IsA<Widget>,
+        tab_label: Option<&impl IsA<Widget>>,
+        menu_label: Option<&impl IsA<Widget>>,
         position: Option<u32>,
-    ) -> u32
-    where
-        T: IsA<Widget>,
-        U: IsA<Widget>,
-        V: IsA<Widget>,
-    {
+    ) -> u32 {
         unsafe {
             let ret = ffi::gtk_notebook_insert_page_menu(
                 self.to_glib_none().0,
@@ -125,7 +116,7 @@ impl Notebook {
         }
     }
     #[doc(alias = "gtk_notebook_page_num")]
-    pub fn page_num<T: IsA<Widget>>(&self, child: &T) -> Option<u32> {
+    pub fn page_num(&self, child: &impl IsA<Widget>) -> Option<u32> {
         unsafe {
             let ret =
                 ffi::gtk_notebook_page_num(self.to_glib_none().0, child.as_ref().to_glib_none().0);
@@ -137,11 +128,11 @@ impl Notebook {
         }
     }
     #[doc(alias = "gtk_notebook_prepend_page")]
-    pub fn prepend_page<T, U>(&self, child: &T, tab_label: Option<&U>) -> u32
-    where
-        T: IsA<Widget>,
-        U: IsA<Widget>,
-    {
+    pub fn prepend_page(
+        &self,
+        child: &impl IsA<Widget>,
+        tab_label: Option<&impl IsA<Widget>>,
+    ) -> u32 {
         unsafe {
             let ret = ffi::gtk_notebook_prepend_page(
                 self.to_glib_none().0,
@@ -154,17 +145,12 @@ impl Notebook {
     }
 
     #[doc(alias = "gtk_notebook_prepend_page_menu")]
-    pub fn prepend_page_menu<T, U, V>(
+    pub fn prepend_page_menu(
         &self,
-        child: &T,
-        tab_label: Option<&U>,
-        menu_label: Option<&V>,
-    ) -> u32
-    where
-        T: IsA<Widget>,
-        U: IsA<Widget>,
-        V: IsA<Widget>,
-    {
+        child: &impl IsA<Widget>,
+        tab_label: Option<&impl IsA<Widget>>,
+        menu_label: Option<&impl IsA<Widget>>,
+    ) -> u32 {
         unsafe {
             let ret = ffi::gtk_notebook_prepend_page_menu(
                 self.to_glib_none().0,
@@ -188,7 +174,7 @@ impl Notebook {
     }
 
     #[doc(alias = "gtk_notebook_reorder_child")]
-    pub fn reorder_child<T: IsA<Widget>>(&self, child: &T, position: Option<u32>) {
+    pub fn reorder_child(&self, child: &impl IsA<Widget>, position: Option<u32>) {
         unsafe {
             ffi::gtk_notebook_reorder_child(
                 self.to_glib_none().0,
diff --git a/gtk4/src/shortcut_trigger.rs b/gtk4/src/shortcut_trigger.rs
index 1c124ed1042a..d1426fea4fc4 100644
--- a/gtk4/src/shortcut_trigger.rs
+++ b/gtk4/src/shortcut_trigger.rs
@@ -8,10 +8,10 @@ use glib::IsA;
 /// Trait containing manually implemented methods of [`ShortcutTrigger`](crate::ShortcutTrigger).
 pub trait ShortcutTriggerExtManual {
     #[doc(alias = "gtk_shortcut_trigger_compare")]
-    fn compare<P: IsA<ShortcutTrigger>>(&self, trigger2: &P) -> std::cmp::Ordering;
+    fn compare(&self, trigger2: &impl IsA<ShortcutTrigger>) -> std::cmp::Ordering;
 
     #[doc(alias = "gtk_shortcut_trigger_equal")]
-    fn equal<P: IsA<ShortcutTrigger>>(&self, trigger2: &P) -> bool;
+    fn equal(&self, trigger2: &impl IsA<ShortcutTrigger>) -> bool;
 
     #[doc(alias = "gtk_shortcut_trigger_hash")]
     fn hash(&self) -> u32;
@@ -21,7 +21,7 @@ pub trait ShortcutTriggerExtManual {
 }
 
 impl<O: IsA<ShortcutTrigger>> ShortcutTriggerExtManual for O {
-    fn compare<P: IsA<ShortcutTrigger>>(&self, trigger2: &P) -> std::cmp::Ordering {
+    fn compare(&self, trigger2: &impl IsA<ShortcutTrigger>) -> std::cmp::Ordering {
         unsafe {
             from_glib(ffi::gtk_shortcut_trigger_compare(
                 ToGlibPtr::<*mut ffi::GtkShortcutTrigger>::to_glib_none(self.as_ref()).0
@@ -32,7 +32,7 @@ impl<O: IsA<ShortcutTrigger>> ShortcutTriggerExtManual for O {
         }
     }
 
-    fn equal<P: IsA<ShortcutTrigger>>(&self, trigger2: &P) -> bool {
+    fn equal(&self, trigger2: &impl IsA<ShortcutTrigger>) -> bool {
         unsafe {
             from_glib(ffi::gtk_shortcut_trigger_equal(
                 ToGlibPtr::<*mut ffi::GtkShortcutTrigger>::to_glib_none(self.as_ref()).0
diff --git a/gtk4/src/text_view.rs b/gtk4/src/text_view.rs
index bcc547d89733..5d7b6fe6064e 100644
--- a/gtk4/src/text_view.rs
+++ b/gtk4/src/text_view.rs
@@ -8,11 +8,11 @@ use glib::IsA;
 /// Trait containing manually implemented methods of [`TextView`](crate::TextView).
 pub trait TextViewExtManual {
     #[doc(alias = "gtk_text_view_im_context_filter_keypress")]
-    fn im_context_filter_keypress<R: AsRef<gdk::Event>>(&self, event: &R) -> bool;
+    fn im_context_filter_keypress(&self, event: &impl AsRef<gdk::Event>) -> bool;
 }
 
 impl<O: IsA<TextView>> TextViewExtManual for O {
-    fn im_context_filter_keypress<R: AsRef<gdk::Event>>(&self, event: &R) -> bool {
+    fn im_context_filter_keypress(&self, event: &impl AsRef<gdk::Event>) -> bool {
         unsafe {
             from_glib(ffi::gtk_text_view_im_context_filter_keypress(
                 self.as_ref().to_glib_none().0,
diff --git a/gtk4/src/tree_model_filter.rs b/gtk4/src/tree_model_filter.rs
index 9666da0c2cb2..ff3582e37869 100644
--- a/gtk4/src/tree_model_filter.rs
+++ b/gtk4/src/tree_model_filter.rs
@@ -8,7 +8,7 @@ use crate::{TreeIter, TreeModel, TreeModelFilter, TreePath};
 
 impl TreeModelFilter {
     #[doc(alias = "gtk_tree_model_filter_new")]
-    pub fn new<T: IsA<TreeModel>>(child_model: &T, root: Option<&TreePath>) -> Self {
+    pub fn new(child_model: &impl IsA<TreeModel>, root: Option<&TreePath>) -> Self {
         skip_assert_initialized!();
         unsafe {
             TreeModel::from_glib_none(ffi::gtk_tree_model_filter_new(
diff --git a/gtk4/src/tree_row_reference.rs b/gtk4/src/tree_row_reference.rs
index 1c71e208b41b..6db20aac05dc 100644
--- a/gtk4/src/tree_row_reference.rs
+++ b/gtk4/src/tree_row_reference.rs
@@ -7,9 +7,9 @@ use glib::IsA;
 
 impl TreeRowReference {
     #[doc(alias = "gtk_tree_row_reference_reordered")]
-    pub fn reordered<P: IsA<glib::Object>>(
+    pub fn reordered(
         &self,
-        proxy: &P,
+        proxy: &impl IsA<glib::Object>,
         path: &TreePath,
         iter: &TreeIter,
         new_order: &[i32],
diff --git a/gtk4/src/tree_view_column.rs b/gtk4/src/tree_view_column.rs
index 4bec73f61b0c..c0d1df4500c1 100644
--- a/gtk4/src/tree_view_column.rs
+++ b/gtk4/src/tree_view_column.rs
@@ -91,7 +91,7 @@ impl TreeViewColumn {
 
     #[doc(alias = "gtk_tree_view_column_set_cell_data_func")]
     #[doc(alias = "set_cell_data_func")]
-    pub fn unset_cell_data_func<P: IsA<CellRenderer>>(&self, cell_renderer: &P) {
+    pub fn unset_cell_data_func(&self, cell_renderer: &impl IsA<CellRenderer>) {
         unsafe {
             ffi::gtk_tree_view_column_set_cell_data_func(
                 self.to_glib_none().0,