diff --git a/gtk4/Gir.toml b/gtk4/Gir.toml
index 89c43147dad9..51d8ff84d7bd 100644
--- a/gtk4/Gir.toml
+++ b/gtk4/Gir.toml
@@ -404,33 +404,50 @@ status = "generate"
 name = "Gtk.AboutDialog"
 status = "generate"
 generate_builder = true
+trust_return_value_nullability = true
     [[object.signal]]
     name = "activate-link"
     inhibit = true
+    # remove_after_upstream_fix
+    # <https://gitlab.gnome.org/GNOME/gtk/-/merge_requests/2873>
+    [[object.function]]
+    name = "get_program_name"
+        [object.function.return]
+        nullable = true
 
 [[object]]
 name = "Gtk.Actionable"
 status = "generate"
+trust_return_value_nullability = true
 manual_traits = ["ActionableExtManual"]
     [[object.property]]
     #value glib.Variant
     name = "action-target"
     ignore = true
+    # remove_after_upstream_fix
+    # <https://gitlab.gnome.org/GNOME/gtk/-/merge_requests/2873>
+    [[object.function]]
+    name = "get_action_target_value"
+        [object.function.return]
+        nullable = true
 
 [[object]]
 name = "Gtk.ActionBar"
 status = "generate"
 generate_builder = true
+trust_return_value_nullability = true
 
 [[object]]
 name = "Gtk.Adjustment"
 status = "generate"
 generate_builder = true
+trust_return_value_nullability = true
 
 [[object]]
 name = "Gtk.AlternativeTrigger"
 status = "generate"
 generate_builder = true
+trust_return_value_nullability = true
 
 [[object]]
 name = "Gtk.AppChooserButton"
@@ -441,34 +458,51 @@ generate_builder = true
 name = "Gtk.AppChooserDialog"
 status = "generate"
 generate_builder = true
-    [[object.function]]
-    name = "get_widget"
-        [object.function.return]
-        nullable = false
+trust_return_value_nullability = true
 
 [[object]]
 name = "Gtk.AppChooserWidget"
 status = "generate"
 generate_builder = true
+trust_return_value_nullability = true
+    # remove_after_upstream_fix
+    # <https://gitlab.gnome.org/GNOME/gtk/-/merge_requests/2873>
+    [[object.function]]
+    name = "get_default_text"
+        [object.function.return]
+        nullable = true
 
 [[object]]
 name = "Gtk.Application"
 status = "generate"
 generate_builder = true
+trust_return_value_nullability = true
 trait_name = "GtkApplicationExt"
     [[object.function]]
     name = "new"
     ignore = true
+    # remove_after_upstream_fix
+    # <https://gitlab.gnome.org/GNOME/gtk/-/merge_requests/2873>
+    [[object.function]]
+    name = "get_menu_by_id"
+        [object.function.return]
+        nullable = true
+    [[object.function]]
+    name = "get_menubar"
+        [object.function.return]
+        nullable = true
 
 [[object]]
 name = "Gtk.ApplicationWindow"
 status = "generate"
 generate_builder = true
+trust_return_value_nullability = true
 
 [[object]]
 name = "Gtk.AspectFrame"
 status = "generate"
 generate_builder = true
+trust_return_value_nullability = true
 
 [[object]]
 name = "Gtk.Assistant"
@@ -765,16 +799,9 @@ manual_traits = ["ConstraintGuideExtManual"]
 name = "Gtk.Dialog"
 status = "generate"
 generate_builder = true
+trust_return_value_nullability = true
 manual_traits = ["DialogExtManual"]
     [[object.function]]
-    name = "add_button"
-        [object.function.return]
-        nullable = false
-    [[object.function]]
-    name = "get_content_area"
-        [object.function.return]
-        nullable = false
-    [[object.function]]
     name = "get_response_for_widget"
     ignore = true
     doc_trait_name = "DialogExtManual"
@@ -842,12 +869,9 @@ manual_traits = ["EditableExtManual"]
 name = "Gtk.Entry"
 status = "generate"
 generate_builder = true
+trust_return_value_nullability = true
 manual_traits = ["EntryExtManual"]
     [[object.function]]
-    name = "get_buffer"
-        [object.function.return]
-        nullable = false
-    [[object.function]]
     name = "get_invisible_char"
     manual = true
     [[object.function]]
@@ -856,15 +880,16 @@ manual_traits = ["EntryExtManual"]
         name = "ch"
         nullable = true
     [[object.function]]
-    name = "set_placeholder_text"
-        [[object.function.parameter]]
-        name = "text"
-        nullable = true
-    [[object.function]]
     name = "set_tabs"
         [[object.function.parameter]]
         name = "tabs"
         const = true
+    # remove_after_upstream_fix
+    # <https://gitlab.gnome.org/GNOME/gtk/-/merge_requests/2873>
+    [[object.function]]
+    name = "get_completion"
+        [object.function.return]
+        nullable = true
 
 [[object]]
 name = "Gtk.EntryBuffer"
@@ -1145,6 +1170,7 @@ manual_traits = ["IMContextSimpleExtManual"]
 name = "Gtk.InfoBar"
 status = "generate"
 generate_builder = true
+trust_return_value_nullability = true
 
 [[object]]
 name = "Gtk.KeyvalTrigger"
@@ -1155,9 +1181,16 @@ generate_builder = true
 name = "Gtk.Label"
 status = "generate"
 generate_builder = true
+trust_return_value_nullability = true
     [[object.signal]]
     name = "activate-link"
     inhibit = true
+    # remove_after_upstream_fix
+    # <https://gitlab.gnome.org/GNOME/gtk/-/merge_requests/2873>
+    [[object.function]]
+    name = "get_extra_menu"
+        [object.function.return]
+        nullable = true
 
 [[object]]
 name = "Gtk.LevelBar"
@@ -1254,6 +1287,7 @@ generate_builder = true
 name = "Gtk.MessageDialog"
 status = "generate"
 generate_builder = true
+trust_return_value_nullability = true
 
 [[object]]
 name = "Gtk.MnemonicTrigger"
@@ -1639,6 +1673,7 @@ generate_builder = true
 name = "Gtk.SpinButton"
 status = "generate"
 generate_builder = true
+trust_return_value_nullability = true
 manual_traits = ["SpinButtonExtManual"]
     [[object.function]]
     name = "get_adjustment"
@@ -1727,16 +1762,9 @@ generate_builder = true
 name = "Gtk.TextBuffer"
 status = "generate"
 generate_builder = true
+trust_return_value_nullability = true
 manual_traits = ["TextBufferExtManual"]
     [[object.function]]
-    name = "register_deserialize_tagset"
-        [object.function.return]
-        nullable = false
-    [[object.function]]
-    name = "register_serialize_tagset"
-        [object.function.return]
-        nullable = false
-    [[object.function]]
     name = "paste_clipboard"
         [[object.function.parameter]]
         name = "override_location"
diff --git a/gtk4/src/auto/alternative_trigger.rs b/gtk4/src/auto/alternative_trigger.rs
index 89df82c116c9..c938de4cd055 100644
--- a/gtk4/src/auto/alternative_trigger.rs
+++ b/gtk4/src/auto/alternative_trigger.rs
@@ -34,7 +34,7 @@ impl AlternativeTrigger {
         }
     }
 
-    pub fn get_first(&self) -> Option<ShortcutTrigger> {
+    pub fn get_first(&self) -> ShortcutTrigger {
         unsafe {
             from_glib_none(gtk_sys::gtk_alternative_trigger_get_first(
                 self.to_glib_none().0,
@@ -42,7 +42,7 @@ impl AlternativeTrigger {
         }
     }
 
-    pub fn get_second(&self) -> Option<ShortcutTrigger> {
+    pub fn get_second(&self) -> ShortcutTrigger {
         unsafe {
             from_glib_none(gtk_sys::gtk_alternative_trigger_get_second(
                 self.to_glib_none().0,
diff --git a/gtk4/src/auto/dialog.rs b/gtk4/src/auto/dialog.rs
index 3fd04e9ed802..e00e01cd90ef 100644
--- a/gtk4/src/auto/dialog.rs
+++ b/gtk4/src/auto/dialog.rs
@@ -541,7 +541,7 @@ pub trait DialogExt: 'static {
 
     fn get_content_area(&self) -> Box;
 
-    fn get_header_bar(&self) -> Option<HeaderBar>;
+    fn get_header_bar(&self) -> HeaderBar;
 
     fn get_widget_for_response(&self, response_id: ResponseType) -> Option<Widget>;
 
@@ -593,7 +593,7 @@ impl<O: IsA<Dialog>> DialogExt for O {
         }
     }
 
-    fn get_header_bar(&self) -> Option<HeaderBar> {
+    fn get_header_bar(&self) -> HeaderBar {
         unsafe {
             from_glib_none(gtk_sys::gtk_dialog_get_header_bar(
                 self.as_ref().to_glib_none().0,
diff --git a/gtk4/src/auto/info_bar.rs b/gtk4/src/auto/info_bar.rs
index fd20b05e733d..67e731a61d40 100644
--- a/gtk4/src/auto/info_bar.rs
+++ b/gtk4/src/auto/info_bar.rs
@@ -59,7 +59,7 @@ impl InfoBar {
         }
     }
 
-    pub fn add_button(&self, button_text: &str, response_id: ResponseType) -> Option<Button> {
+    pub fn add_button(&self, button_text: &str, response_id: ResponseType) -> Button {
         unsafe {
             from_glib_none(gtk_sys::gtk_info_bar_add_button(
                 self.to_glib_none().0,
diff --git a/gtk4/src/auto/label.rs b/gtk4/src/auto/label.rs
index 452efc47fe4c..9ff4a1719ae7 100644
--- a/gtk4/src/auto/label.rs
+++ b/gtk4/src/auto/label.rs
@@ -79,11 +79,11 @@ impl Label {
         unsafe { from_glib(gtk_sys::gtk_label_get_justify(self.to_glib_none().0)) }
     }
 
-    pub fn get_label(&self) -> Option<GString> {
+    pub fn get_label(&self) -> GString {
         unsafe { from_glib_none(gtk_sys::gtk_label_get_label(self.to_glib_none().0)) }
     }
 
-    pub fn get_layout(&self) -> Option<pango::Layout> {
+    pub fn get_layout(&self) -> pango::Layout {
         unsafe { from_glib_none(gtk_sys::gtk_label_get_layout(self.to_glib_none().0)) }
     }
 
@@ -153,7 +153,7 @@ impl Label {
         }
     }
 
-    pub fn get_text(&self) -> Option<GString> {
+    pub fn get_text(&self) -> GString {
         unsafe { from_glib_none(gtk_sys::gtk_label_get_text(self.to_glib_none().0)) }
     }
 
diff --git a/gtk4/src/auto/message_dialog.rs b/gtk4/src/auto/message_dialog.rs
index 7e2a9c9df1a9..383adc1d1853 100644
--- a/gtk4/src/auto/message_dialog.rs
+++ b/gtk4/src/auto/message_dialog.rs
@@ -61,7 +61,7 @@ impl MessageDialog {
     //    unsafe { TODO: call gtk_sys:gtk_message_dialog_format_secondary_text() }
     //}
 
-    pub fn get_message_area(&self) -> Option<Widget> {
+    pub fn get_message_area(&self) -> Widget {
         unsafe {
             from_glib_none(gtk_sys::gtk_message_dialog_get_message_area(
                 self.to_glib_none().0,
diff --git a/gtk4/src/auto/text_buffer.rs b/gtk4/src/auto/text_buffer.rs
index 476e3ae9b802..efa2e2f8c5b0 100644
--- a/gtk4/src/auto/text_buffer.rs
+++ b/gtk4/src/auto/text_buffer.rs
@@ -105,16 +105,16 @@ pub trait TextBufferExt: 'static {
 
     fn copy_clipboard(&self, clipboard: &gdk::Clipboard);
 
-    fn create_child_anchor(&self, iter: &mut TextIter) -> Option<TextChildAnchor>;
+    fn create_child_anchor(&self, iter: &mut TextIter) -> TextChildAnchor;
 
     fn create_mark(
         &self,
         mark_name: Option<&str>,
         where_: &TextIter,
         left_gravity: bool,
-    ) -> Option<TextMark>;
+    ) -> TextMark;
 
-    //fn create_tag(&self, tag_name: Option<&str>, first_property_name: Option<&str>, : /*Unknown conversion*//*Unimplemented*/Fundamental: VarArgs) -> Option<TextTag>;
+    //fn create_tag(&self, tag_name: Option<&str>, first_property_name: Option<&str>, : /*Unknown conversion*//*Unimplemented*/Fundamental: VarArgs) -> TextTag;
 
     fn cut_clipboard(&self, clipboard: &gdk::Clipboard, default_editable: bool);
 
@@ -151,7 +151,7 @@ pub trait TextBufferExt: 'static {
 
     fn get_has_selection(&self) -> bool;
 
-    fn get_insert(&self) -> Option<TextMark>;
+    fn get_insert(&self) -> TextMark;
 
     fn get_iter_at_child_anchor<P: IsA<TextChildAnchor>>(&self, anchor: &P) -> TextIter;
 
@@ -173,29 +173,19 @@ pub trait TextBufferExt: 'static {
 
     fn get_modified(&self) -> bool;
 
-    fn get_selection_bound(&self) -> Option<TextMark>;
+    fn get_selection_bound(&self) -> TextMark;
 
     fn get_selection_bounds(&self) -> Option<(TextIter, TextIter)>;
 
-    fn get_selection_content(&self) -> Option<gdk::ContentProvider>;
+    fn get_selection_content(&self) -> gdk::ContentProvider;
 
-    fn get_slice(
-        &self,
-        start: &TextIter,
-        end: &TextIter,
-        include_hidden_chars: bool,
-    ) -> Option<GString>;
+    fn get_slice(&self, start: &TextIter, end: &TextIter, include_hidden_chars: bool) -> GString;
 
     fn get_start_iter(&self) -> TextIter;
 
-    fn get_tag_table(&self) -> Option<TextTagTable>;
+    fn get_tag_table(&self) -> TextTagTable;
 
-    fn get_text(
-        &self,
-        start: &TextIter,
-        end: &TextIter,
-        include_hidden_chars: bool,
-    ) -> Option<GString>;
+    fn get_text(&self, start: &TextIter, end: &TextIter, include_hidden_chars: bool) -> GString;
 
     fn insert(&self, iter: &mut TextIter, text: &str);
 
@@ -415,7 +405,7 @@ impl<O: IsA<TextBuffer>> TextBufferExt for O {
         }
     }
 
-    fn create_child_anchor(&self, iter: &mut TextIter) -> Option<TextChildAnchor> {
+    fn create_child_anchor(&self, iter: &mut TextIter) -> TextChildAnchor {
         unsafe {
             from_glib_none(gtk_sys::gtk_text_buffer_create_child_anchor(
                 self.as_ref().to_glib_none().0,
@@ -429,7 +419,7 @@ impl<O: IsA<TextBuffer>> TextBufferExt for O {
         mark_name: Option<&str>,
         where_: &TextIter,
         left_gravity: bool,
-    ) -> Option<TextMark> {
+    ) -> TextMark {
         unsafe {
             from_glib_none(gtk_sys::gtk_text_buffer_create_mark(
                 self.as_ref().to_glib_none().0,
@@ -440,7 +430,7 @@ impl<O: IsA<TextBuffer>> TextBufferExt for O {
         }
     }
 
-    //fn create_tag(&self, tag_name: Option<&str>, first_property_name: Option<&str>, : /*Unknown conversion*//*Unimplemented*/Fundamental: VarArgs) -> Option<TextTag> {
+    //fn create_tag(&self, tag_name: Option<&str>, first_property_name: Option<&str>, : /*Unknown conversion*//*Unimplemented*/Fundamental: VarArgs) -> TextTag {
     //    unsafe { TODO: call gtk_sys:gtk_text_buffer_create_tag() }
     //}
 
@@ -580,7 +570,7 @@ impl<O: IsA<TextBuffer>> TextBufferExt for O {
         }
     }
 
-    fn get_insert(&self) -> Option<TextMark> {
+    fn get_insert(&self) -> TextMark {
         unsafe {
             from_glib_none(gtk_sys::gtk_text_buffer_get_insert(
                 self.as_ref().to_glib_none().0,
@@ -699,7 +689,7 @@ impl<O: IsA<TextBuffer>> TextBufferExt for O {
         }
     }
 
-    fn get_selection_bound(&self) -> Option<TextMark> {
+    fn get_selection_bound(&self) -> TextMark {
         unsafe {
             from_glib_none(gtk_sys::gtk_text_buffer_get_selection_bound(
                 self.as_ref().to_glib_none().0,
@@ -724,7 +714,7 @@ impl<O: IsA<TextBuffer>> TextBufferExt for O {
         }
     }
 
-    fn get_selection_content(&self) -> Option<gdk::ContentProvider> {
+    fn get_selection_content(&self) -> gdk::ContentProvider {
         unsafe {
             from_glib_full(gtk_sys::gtk_text_buffer_get_selection_content(
                 self.as_ref().to_glib_none().0,
@@ -732,12 +722,7 @@ impl<O: IsA<TextBuffer>> TextBufferExt for O {
         }
     }
 
-    fn get_slice(
-        &self,
-        start: &TextIter,
-        end: &TextIter,
-        include_hidden_chars: bool,
-    ) -> Option<GString> {
+    fn get_slice(&self, start: &TextIter, end: &TextIter, include_hidden_chars: bool) -> GString {
         unsafe {
             from_glib_full(gtk_sys::gtk_text_buffer_get_slice(
                 self.as_ref().to_glib_none().0,
@@ -759,7 +744,7 @@ impl<O: IsA<TextBuffer>> TextBufferExt for O {
         }
     }
 
-    fn get_tag_table(&self) -> Option<TextTagTable> {
+    fn get_tag_table(&self) -> TextTagTable {
         unsafe {
             from_glib_none(gtk_sys::gtk_text_buffer_get_tag_table(
                 self.as_ref().to_glib_none().0,
@@ -767,12 +752,7 @@ impl<O: IsA<TextBuffer>> TextBufferExt for O {
         }
     }
 
-    fn get_text(
-        &self,
-        start: &TextIter,
-        end: &TextIter,
-        include_hidden_chars: bool,
-    ) -> Option<GString> {
+    fn get_text(&self, start: &TextIter, end: &TextIter, include_hidden_chars: bool) -> GString {
         unsafe {
             from_glib_full(gtk_sys::gtk_text_buffer_get_text(
                 self.as_ref().to_glib_none().0,