diff --git a/gir b/gir
index 8b9d0bb3..fbb95f48 160000
--- a/gir
+++ b/gir
@@ -1 +1 @@
-Subproject commit 8b9d0bb32ed3b76ff9931ee283c07d32af955b60
+Subproject commit fbb95f484ed5f202af9594b6c8d4f59fc0501bf1
diff --git a/src/auto/authentication_request.rs b/src/auto/authentication_request.rs
index 478b24f3..ade114a9 100644
--- a/src/auto/authentication_request.rs
+++ b/src/auto/authentication_request.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
@@ -142,6 +142,7 @@ impl<O: IsA<AuthenticationRequest> + IsA<glib::object::Object>> AuthenticationRe
 #[cfg(any(feature = "v2_2", feature = "dox"))]
 unsafe extern "C" fn cancelled_trampoline<P>(this: *mut ffi::WebKitAuthenticationRequest, f: glib_ffi::gpointer)
 where P: IsA<AuthenticationRequest> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&AuthenticationRequest::from_glib_borrow(this).downcast_unchecked())
 }
diff --git a/src/auto/back_forward_list.rs b/src/auto/back_forward_list.rs
index 5a0a0ccb..19e14b3f 100644
--- a/src/auto/back_forward_list.rs
+++ b/src/auto/back_forward_list.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
diff --git a/src/auto/back_forward_list_item.rs b/src/auto/back_forward_list_item.rs
index a3856cdd..3c3c6dda 100644
--- a/src/auto/back_forward_list_item.rs
+++ b/src/auto/back_forward_list_item.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
diff --git a/src/auto/color_chooser_request.rs b/src/auto/color_chooser_request.rs
index a86aaca4..02b56084 100644
--- a/src/auto/color_chooser_request.rs
+++ b/src/auto/color_chooser_request.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
@@ -128,12 +128,14 @@ impl<O: IsA<ColorChooserRequest> + IsA<glib::object::Object>> ColorChooserReques
 #[cfg(any(feature = "v2_8", feature = "dox"))]
 unsafe extern "C" fn finished_trampoline<P>(this: *mut ffi::WebKitColorChooserRequest, f: glib_ffi::gpointer)
 where P: IsA<ColorChooserRequest> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&ColorChooserRequest::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_rgba_trampoline<P>(this: *mut ffi::WebKitColorChooserRequest, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<ColorChooserRequest> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&ColorChooserRequest::from_glib_borrow(this).downcast_unchecked())
 }
diff --git a/src/auto/context_menu.rs b/src/auto/context_menu.rs
index eaef018a..2feae110 100644
--- a/src/auto/context_menu.rs
+++ b/src/auto/context_menu.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
diff --git a/src/auto/context_menu_item.rs b/src/auto/context_menu_item.rs
index 66a7409e..bedd0347 100644
--- a/src/auto/context_menu_item.rs
+++ b/src/auto/context_menu_item.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
diff --git a/src/auto/cookie_manager.rs b/src/auto/cookie_manager.rs
index fa56e21e..76445ea3 100644
--- a/src/auto/cookie_manager.rs
+++ b/src/auto/cookie_manager.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
@@ -89,6 +89,7 @@ impl<O: IsA<CookieManager> + IsA<glib::object::Object>> CookieManagerExt for O {
 
 unsafe extern "C" fn changed_trampoline<P>(this: *mut ffi::WebKitCookieManager, f: glib_ffi::gpointer)
 where P: IsA<CookieManager> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&CookieManager::from_glib_borrow(this).downcast_unchecked())
 }
diff --git a/src/auto/credential.rs b/src/auto/credential.rs
index 2076f92a..e2859f5d 100644
--- a/src/auto/credential.rs
+++ b/src/auto/credential.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
diff --git a/src/auto/download.rs b/src/auto/download.rs
index eeb7669e..74d9c392 100644
--- a/src/auto/download.rs
+++ b/src/auto/download.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
@@ -219,30 +219,35 @@ impl<O: IsA<Download> + IsA<glib::object::Object>> DownloadExt for O {
 
 unsafe extern "C" fn created_destination_trampoline<P>(this: *mut ffi::WebKitDownload, destination: *mut libc::c_char, f: glib_ffi::gpointer)
 where P: IsA<Download> {
+    callback_guard!();
     let f: &&(Fn(&P, &str) + 'static) = transmute(f);
     f(&Download::from_glib_borrow(this).downcast_unchecked(), &String::from_glib_none(destination))
 }
 
 unsafe extern "C" fn decide_destination_trampoline<P>(this: *mut ffi::WebKitDownload, suggested_filename: *mut libc::c_char, f: glib_ffi::gpointer) -> glib_ffi::gboolean
 where P: IsA<Download> {
+    callback_guard!();
     let f: &&(Fn(&P, &str) -> bool + 'static) = transmute(f);
     f(&Download::from_glib_borrow(this).downcast_unchecked(), &String::from_glib_none(suggested_filename)).to_glib()
 }
 
 unsafe extern "C" fn failed_trampoline<P>(this: *mut ffi::WebKitDownload, error: *mut glib_ffi::GError, f: glib_ffi::gpointer)
 where P: IsA<Download> {
+    callback_guard!();
     let f: &&(Fn(&P, &Error) + 'static) = transmute(f);
     f(&Download::from_glib_borrow(this).downcast_unchecked(), &from_glib_borrow(error))
 }
 
 unsafe extern "C" fn finished_trampoline<P>(this: *mut ffi::WebKitDownload, f: glib_ffi::gpointer)
 where P: IsA<Download> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Download::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn received_data_trampoline<P>(this: *mut ffi::WebKitDownload, data_length: u64, f: glib_ffi::gpointer)
 where P: IsA<Download> {
+    callback_guard!();
     let f: &&(Fn(&P, u64) + 'static) = transmute(f);
     f(&Download::from_glib_borrow(this).downcast_unchecked(), data_length)
 }
@@ -250,24 +255,28 @@ where P: IsA<Download> {
 #[cfg(any(feature = "v2_6", feature = "dox"))]
 unsafe extern "C" fn notify_allow_overwrite_trampoline<P>(this: *mut ffi::WebKitDownload, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Download> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Download::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_destination_trampoline<P>(this: *mut ffi::WebKitDownload, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Download> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Download::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_estimated_progress_trampoline<P>(this: *mut ffi::WebKitDownload, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Download> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Download::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_response_trampoline<P>(this: *mut ffi::WebKitDownload, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Download> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Download::from_glib_borrow(this).downcast_unchecked())
 }
diff --git a/src/auto/editor_state.rs b/src/auto/editor_state.rs
index 8331cadf..cff631b1 100644
--- a/src/auto/editor_state.rs
+++ b/src/auto/editor_state.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
@@ -58,6 +58,7 @@ impl<O: IsA<EditorState> + IsA<glib::object::Object>> EditorStateExt for O {
 #[cfg(any(feature = "v2_10", feature = "dox"))]
 unsafe extern "C" fn notify_typing_attributes_trampoline<P>(this: *mut ffi::WebKitEditorState, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<EditorState> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&EditorState::from_glib_borrow(this).downcast_unchecked())
 }
diff --git a/src/auto/enums.rs b/src/auto/enums.rs
index e80a66fe..6944ea92 100644
--- a/src/auto/enums.rs
+++ b/src/auto/enums.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
diff --git a/src/auto/favicon_database.rs b/src/auto/favicon_database.rs
index d07ae05a..ae7189d7 100644
--- a/src/auto/favicon_database.rs
+++ b/src/auto/favicon_database.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
@@ -63,6 +63,7 @@ impl<O: IsA<FaviconDatabase> + IsA<glib::object::Object>> FaviconDatabaseExt for
 
 unsafe extern "C" fn favicon_changed_trampoline<P>(this: *mut ffi::WebKitFaviconDatabase, page_uri: *mut libc::c_char, favicon_uri: *mut libc::c_char, f: glib_ffi::gpointer)
 where P: IsA<FaviconDatabase> {
+    callback_guard!();
     let f: &&(Fn(&P, &str, &str) + 'static) = transmute(f);
     f(&FaviconDatabase::from_glib_borrow(this).downcast_unchecked(), &String::from_glib_none(page_uri), &String::from_glib_none(favicon_uri))
 }
diff --git a/src/auto/file_chooser_request.rs b/src/auto/file_chooser_request.rs
index 73564e75..19736715 100644
--- a/src/auto/file_chooser_request.rs
+++ b/src/auto/file_chooser_request.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
@@ -131,24 +131,28 @@ impl<O: IsA<FileChooserRequest> + IsA<glib::object::Object>> FileChooserRequestE
 
 unsafe extern "C" fn notify_filter_trampoline<P>(this: *mut ffi::WebKitFileChooserRequest, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<FileChooserRequest> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&FileChooserRequest::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_mime_types_trampoline<P>(this: *mut ffi::WebKitFileChooserRequest, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<FileChooserRequest> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&FileChooserRequest::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_select_multiple_trampoline<P>(this: *mut ffi::WebKitFileChooserRequest, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<FileChooserRequest> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&FileChooserRequest::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_selected_files_trampoline<P>(this: *mut ffi::WebKitFileChooserRequest, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<FileChooserRequest> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&FileChooserRequest::from_glib_borrow(this).downcast_unchecked())
 }
diff --git a/src/auto/find_controller.rs b/src/auto/find_controller.rs
index 69d56cd5..4876dc6e 100644
--- a/src/auto/find_controller.rs
+++ b/src/auto/find_controller.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
@@ -186,42 +186,49 @@ impl<O: IsA<FindController> + IsA<glib::object::Object>> FindControllerExt for O
 
 unsafe extern "C" fn counted_matches_trampoline<P>(this: *mut ffi::WebKitFindController, match_count: libc::c_uint, f: glib_ffi::gpointer)
 where P: IsA<FindController> {
+    callback_guard!();
     let f: &&(Fn(&P, u32) + 'static) = transmute(f);
     f(&FindController::from_glib_borrow(this).downcast_unchecked(), match_count)
 }
 
 unsafe extern "C" fn failed_to_find_text_trampoline<P>(this: *mut ffi::WebKitFindController, f: glib_ffi::gpointer)
 where P: IsA<FindController> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&FindController::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn found_text_trampoline<P>(this: *mut ffi::WebKitFindController, match_count: libc::c_uint, f: glib_ffi::gpointer)
 where P: IsA<FindController> {
+    callback_guard!();
     let f: &&(Fn(&P, u32) + 'static) = transmute(f);
     f(&FindController::from_glib_borrow(this).downcast_unchecked(), match_count)
 }
 
 unsafe extern "C" fn notify_max_match_count_trampoline<P>(this: *mut ffi::WebKitFindController, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<FindController> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&FindController::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_options_trampoline<P>(this: *mut ffi::WebKitFindController, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<FindController> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&FindController::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_text_trampoline<P>(this: *mut ffi::WebKitFindController, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<FindController> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&FindController::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_web_view_trampoline<P>(this: *mut ffi::WebKitFindController, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<FindController> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&FindController::from_glib_borrow(this).downcast_unchecked())
 }
diff --git a/src/auto/flags.rs b/src/auto/flags.rs
index a0ea0453..2c34c87e 100644
--- a/src/auto/flags.rs
+++ b/src/auto/flags.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
diff --git a/src/auto/form_submission_request.rs b/src/auto/form_submission_request.rs
index 6efa4bb7..eb305be8 100644
--- a/src/auto/form_submission_request.rs
+++ b/src/auto/form_submission_request.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
diff --git a/src/auto/geolocation_permission_request.rs b/src/auto/geolocation_permission_request.rs
index 6590ac03..01f16737 100644
--- a/src/auto/geolocation_permission_request.rs
+++ b/src/auto/geolocation_permission_request.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
diff --git a/src/auto/hit_test_result.rs b/src/auto/hit_test_result.rs
index 0abedafa..1c5cb1c2 100644
--- a/src/auto/hit_test_result.rs
+++ b/src/auto/hit_test_result.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
@@ -188,36 +188,42 @@ impl<O: IsA<HitTestResult> + IsA<glib::object::Object>> HitTestResultExt for O {
 
 unsafe extern "C" fn notify_context_trampoline<P>(this: *mut ffi::WebKitHitTestResult, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<HitTestResult> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&HitTestResult::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_image_uri_trampoline<P>(this: *mut ffi::WebKitHitTestResult, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<HitTestResult> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&HitTestResult::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_link_label_trampoline<P>(this: *mut ffi::WebKitHitTestResult, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<HitTestResult> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&HitTestResult::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_link_title_trampoline<P>(this: *mut ffi::WebKitHitTestResult, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<HitTestResult> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&HitTestResult::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_link_uri_trampoline<P>(this: *mut ffi::WebKitHitTestResult, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<HitTestResult> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&HitTestResult::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_media_uri_trampoline<P>(this: *mut ffi::WebKitHitTestResult, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<HitTestResult> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&HitTestResult::from_glib_borrow(this).downcast_unchecked())
 }
diff --git a/src/auto/install_missing_media_plugins_permission_request.rs b/src/auto/install_missing_media_plugins_permission_request.rs
index c75bfea1..b0624ace 100644
--- a/src/auto/install_missing_media_plugins_permission_request.rs
+++ b/src/auto/install_missing_media_plugins_permission_request.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
diff --git a/src/auto/javascript_result.rs b/src/auto/javascript_result.rs
index b6fba313..2a801806 100644
--- a/src/auto/javascript_result.rs
+++ b/src/auto/javascript_result.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
diff --git a/src/auto/mime_info.rs b/src/auto/mime_info.rs
index 884f5bb7..5c9962e3 100644
--- a/src/auto/mime_info.rs
+++ b/src/auto/mime_info.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
diff --git a/src/auto/mod.rs b/src/auto/mod.rs
index 1a1babbb..95661a52 100644
--- a/src/auto/mod.rs
+++ b/src/auto/mod.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
diff --git a/src/auto/navigation_action.rs b/src/auto/navigation_action.rs
index 688b4e2d..fc337d75 100644
--- a/src/auto/navigation_action.rs
+++ b/src/auto/navigation_action.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
diff --git a/src/auto/navigation_policy_decision.rs b/src/auto/navigation_policy_decision.rs
index a1bbc550..b75a1cac 100644
--- a/src/auto/navigation_policy_decision.rs
+++ b/src/auto/navigation_policy_decision.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
@@ -155,18 +155,21 @@ impl<O: IsA<NavigationPolicyDecision> + IsA<glib::object::Object>> NavigationPol
 
 unsafe extern "C" fn notify_frame_name_trampoline<P>(this: *mut ffi::WebKitNavigationPolicyDecision, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<NavigationPolicyDecision> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&NavigationPolicyDecision::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_modifiers_trampoline<P>(this: *mut ffi::WebKitNavigationPolicyDecision, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<NavigationPolicyDecision> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&NavigationPolicyDecision::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_mouse_button_trampoline<P>(this: *mut ffi::WebKitNavigationPolicyDecision, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<NavigationPolicyDecision> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&NavigationPolicyDecision::from_glib_borrow(this).downcast_unchecked())
 }
@@ -174,18 +177,21 @@ where P: IsA<NavigationPolicyDecision> {
 #[cfg(any(feature = "v2_6", feature = "dox"))]
 unsafe extern "C" fn notify_navigation_action_trampoline<P>(this: *mut ffi::WebKitNavigationPolicyDecision, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<NavigationPolicyDecision> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&NavigationPolicyDecision::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_navigation_type_trampoline<P>(this: *mut ffi::WebKitNavigationPolicyDecision, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<NavigationPolicyDecision> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&NavigationPolicyDecision::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_request_trampoline<P>(this: *mut ffi::WebKitNavigationPolicyDecision, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<NavigationPolicyDecision> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&NavigationPolicyDecision::from_glib_borrow(this).downcast_unchecked())
 }
diff --git a/src/auto/network_proxy_settings.rs b/src/auto/network_proxy_settings.rs
index d5a8f27b..446a1e2c 100644
--- a/src/auto/network_proxy_settings.rs
+++ b/src/auto/network_proxy_settings.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
diff --git a/src/auto/notification.rs b/src/auto/notification.rs
index 98529814..79e10e10 100644
--- a/src/auto/notification.rs
+++ b/src/auto/notification.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
@@ -168,6 +168,7 @@ impl<O: IsA<Notification> + IsA<glib::object::Object>> NotificationExt for O {
 #[cfg(any(feature = "v2_12", feature = "dox"))]
 unsafe extern "C" fn clicked_trampoline<P>(this: *mut ffi::WebKitNotification, f: glib_ffi::gpointer)
 where P: IsA<Notification> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Notification::from_glib_borrow(this).downcast_unchecked())
 }
@@ -175,6 +176,7 @@ where P: IsA<Notification> {
 #[cfg(any(feature = "v2_8", feature = "dox"))]
 unsafe extern "C" fn closed_trampoline<P>(this: *mut ffi::WebKitNotification, f: glib_ffi::gpointer)
 where P: IsA<Notification> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Notification::from_glib_borrow(this).downcast_unchecked())
 }
@@ -182,6 +184,7 @@ where P: IsA<Notification> {
 #[cfg(any(feature = "v2_8", feature = "dox"))]
 unsafe extern "C" fn notify_body_trampoline<P>(this: *mut ffi::WebKitNotification, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Notification> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Notification::from_glib_borrow(this).downcast_unchecked())
 }
@@ -189,6 +192,7 @@ where P: IsA<Notification> {
 #[cfg(any(feature = "v2_8", feature = "dox"))]
 unsafe extern "C" fn notify_id_trampoline<P>(this: *mut ffi::WebKitNotification, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Notification> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Notification::from_glib_borrow(this).downcast_unchecked())
 }
@@ -196,6 +200,7 @@ where P: IsA<Notification> {
 #[cfg(any(feature = "v2_16", feature = "dox"))]
 unsafe extern "C" fn notify_tag_trampoline<P>(this: *mut ffi::WebKitNotification, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Notification> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Notification::from_glib_borrow(this).downcast_unchecked())
 }
@@ -203,6 +208,7 @@ where P: IsA<Notification> {
 #[cfg(any(feature = "v2_8", feature = "dox"))]
 unsafe extern "C" fn notify_title_trampoline<P>(this: *mut ffi::WebKitNotification, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Notification> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Notification::from_glib_borrow(this).downcast_unchecked())
 }
diff --git a/src/auto/notification_permission_request.rs b/src/auto/notification_permission_request.rs
index e5e5d31c..78407fbe 100644
--- a/src/auto/notification_permission_request.rs
+++ b/src/auto/notification_permission_request.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
diff --git a/src/auto/permission_request.rs b/src/auto/permission_request.rs
index 8e10e4aa..1a6083e9 100644
--- a/src/auto/permission_request.rs
+++ b/src/auto/permission_request.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
diff --git a/src/auto/plugin.rs b/src/auto/plugin.rs
index a9df5c29..7a873cf9 100644
--- a/src/auto/plugin.rs
+++ b/src/auto/plugin.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
diff --git a/src/auto/policy_decision.rs b/src/auto/policy_decision.rs
index 76f3aaae..64ab9970 100644
--- a/src/auto/policy_decision.rs
+++ b/src/auto/policy_decision.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
diff --git a/src/auto/print_custom_widget.rs b/src/auto/print_custom_widget.rs
index e3f7542e..e567fe97 100644
--- a/src/auto/print_custom_widget.rs
+++ b/src/auto/print_custom_widget.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
@@ -118,6 +118,7 @@ impl<O: IsA<PrintCustomWidget> + IsA<glib::object::Object>> PrintCustomWidgetExt
 #[cfg(any(feature = "v2_16", feature = "dox"))]
 unsafe extern "C" fn apply_trampoline<P>(this: *mut ffi::WebKitPrintCustomWidget, f: glib_ffi::gpointer)
 where P: IsA<PrintCustomWidget> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&PrintCustomWidget::from_glib_borrow(this).downcast_unchecked())
 }
@@ -125,6 +126,7 @@ where P: IsA<PrintCustomWidget> {
 #[cfg(any(feature = "v2_16", feature = "dox"))]
 unsafe extern "C" fn update_trampoline<P>(this: *mut ffi::WebKitPrintCustomWidget, page_setup: *mut gtk_ffi::GtkPageSetup, print_settings: *mut gtk_ffi::GtkPrintSettings, f: glib_ffi::gpointer)
 where P: IsA<PrintCustomWidget> {
+    callback_guard!();
     let f: &&(Fn(&P, &gtk::PageSetup, &gtk::PrintSettings) + 'static) = transmute(f);
     f(&PrintCustomWidget::from_glib_borrow(this).downcast_unchecked(), &from_glib_borrow(page_setup), &from_glib_borrow(print_settings))
 }
@@ -132,6 +134,7 @@ where P: IsA<PrintCustomWidget> {
 #[cfg(any(feature = "v2_16", feature = "dox"))]
 unsafe extern "C" fn notify_title_trampoline<P>(this: *mut ffi::WebKitPrintCustomWidget, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<PrintCustomWidget> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&PrintCustomWidget::from_glib_borrow(this).downcast_unchecked())
 }
@@ -139,6 +142,7 @@ where P: IsA<PrintCustomWidget> {
 #[cfg(any(feature = "v2_16", feature = "dox"))]
 unsafe extern "C" fn notify_widget_trampoline<P>(this: *mut ffi::WebKitPrintCustomWidget, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<PrintCustomWidget> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&PrintCustomWidget::from_glib_borrow(this).downcast_unchecked())
 }
diff --git a/src/auto/print_operation.rs b/src/auto/print_operation.rs
index f6997b60..39c6d895 100644
--- a/src/auto/print_operation.rs
+++ b/src/auto/print_operation.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
@@ -170,36 +170,42 @@ impl<O: IsA<PrintOperation> + IsA<glib::object::Object>> PrintOperationExt for O
 #[cfg(any(feature = "v2_16", feature = "dox"))]
 unsafe extern "C" fn create_custom_widget_trampoline<P>(this: *mut ffi::WebKitPrintOperation, f: glib_ffi::gpointer) -> *mut ffi::WebKitPrintCustomWidget
 where P: IsA<PrintOperation> {
+    callback_guard!();
     let f: &&(Fn(&P) -> PrintCustomWidget + 'static) = transmute(f);
     f(&PrintOperation::from_glib_borrow(this).downcast_unchecked()).to_glib_full()
 }
 
 unsafe extern "C" fn failed_trampoline<P>(this: *mut ffi::WebKitPrintOperation, error: *mut glib_ffi::GError, f: glib_ffi::gpointer)
 where P: IsA<PrintOperation> {
+    callback_guard!();
     let f: &&(Fn(&P, &Error) + 'static) = transmute(f);
     f(&PrintOperation::from_glib_borrow(this).downcast_unchecked(), &from_glib_borrow(error))
 }
 
 unsafe extern "C" fn finished_trampoline<P>(this: *mut ffi::WebKitPrintOperation, f: glib_ffi::gpointer)
 where P: IsA<PrintOperation> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&PrintOperation::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_page_setup_trampoline<P>(this: *mut ffi::WebKitPrintOperation, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<PrintOperation> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&PrintOperation::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_print_settings_trampoline<P>(this: *mut ffi::WebKitPrintOperation, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<PrintOperation> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&PrintOperation::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_web_view_trampoline<P>(this: *mut ffi::WebKitPrintOperation, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<PrintOperation> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&PrintOperation::from_glib_borrow(this).downcast_unchecked())
 }
diff --git a/src/auto/response_policy_decision.rs b/src/auto/response_policy_decision.rs
index 56cfc33f..4e335269 100644
--- a/src/auto/response_policy_decision.rs
+++ b/src/auto/response_policy_decision.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
@@ -79,12 +79,14 @@ impl<O: IsA<ResponsePolicyDecision> + IsA<glib::object::Object>> ResponsePolicyD
 
 unsafe extern "C" fn notify_request_trampoline<P>(this: *mut ffi::WebKitResponsePolicyDecision, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<ResponsePolicyDecision> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&ResponsePolicyDecision::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_response_trampoline<P>(this: *mut ffi::WebKitResponsePolicyDecision, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<ResponsePolicyDecision> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&ResponsePolicyDecision::from_glib_borrow(this).downcast_unchecked())
 }
diff --git a/src/auto/security_manager.rs b/src/auto/security_manager.rs
index ddd21c06..ccdac07c 100644
--- a/src/auto/security_manager.rs
+++ b/src/auto/security_manager.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
diff --git a/src/auto/security_origin.rs b/src/auto/security_origin.rs
index 893d8934..11be436c 100644
--- a/src/auto/security_origin.rs
+++ b/src/auto/security_origin.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
diff --git a/src/auto/settings.rs b/src/auto/settings.rs
index 73a56c22..d8178310 100644
--- a/src/auto/settings.rs
+++ b/src/auto/settings.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
@@ -1443,12 +1443,14 @@ impl<O: IsA<Settings> + IsA<glib::object::Object>> SettingsExt for O {
 #[cfg(any(feature = "v2_10", feature = "dox"))]
 unsafe extern "C" fn notify_allow_file_access_from_file_urls_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_allow_modal_dialogs_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
@@ -1456,48 +1458,56 @@ where P: IsA<Settings> {
 #[cfg(any(feature = "v2_14", feature = "dox"))]
 unsafe extern "C" fn notify_allow_universal_access_from_file_urls_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_auto_load_images_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_cursive_font_family_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_default_charset_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_default_font_family_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_default_font_size_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_default_monospace_font_size_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_draw_compositing_indicators_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
@@ -1505,66 +1515,77 @@ where P: IsA<Settings> {
 #[cfg(any(feature = "v2_2", feature = "dox"))]
 unsafe extern "C" fn notify_enable_accelerated_2d_canvas_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_enable_caret_browsing_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_enable_developer_extras_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_enable_dns_prefetching_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_enable_frame_flattening_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_enable_fullscreen_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_enable_html5_database_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_enable_html5_local_storage_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_enable_hyperlink_auditing_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_enable_java_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_enable_javascript_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
@@ -1572,6 +1593,7 @@ where P: IsA<Settings> {
 #[cfg(any(feature = "v2_4", feature = "dox"))]
 unsafe extern "C" fn notify_enable_media_stream_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
@@ -1579,48 +1601,56 @@ where P: IsA<Settings> {
 #[cfg(any(feature = "v2_4", feature = "dox"))]
 unsafe extern "C" fn notify_enable_mediasource_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_enable_offline_web_application_cache_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_enable_page_cache_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_enable_plugins_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_enable_private_browsing_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_enable_resizable_text_areas_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_enable_site_specific_quirks_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_enable_smooth_scrolling_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
@@ -1628,24 +1658,28 @@ where P: IsA<Settings> {
 #[cfg(any(feature = "v2_4", feature = "dox"))]
 unsafe extern "C" fn notify_enable_spatial_navigation_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_enable_tabs_to_links_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_enable_webaudio_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_enable_webgl_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
@@ -1653,18 +1687,21 @@ where P: IsA<Settings> {
 #[cfg(any(feature = "v2_2", feature = "dox"))]
 unsafe extern "C" fn notify_enable_write_console_messages_to_stdout_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_enable_xss_auditor_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_fantasy_font_family_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
@@ -1672,84 +1709,98 @@ where P: IsA<Settings> {
 #[cfg(any(feature = "v2_16", feature = "dox"))]
 unsafe extern "C" fn notify_hardware_acceleration_policy_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_javascript_can_access_clipboard_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_javascript_can_open_windows_automatically_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_load_icons_ignoring_image_load_setting_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_media_playback_allows_inline_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_media_playback_requires_user_gesture_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_minimum_font_size_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_monospace_font_family_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_pictograph_font_family_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_print_backgrounds_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_sans_serif_font_family_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_serif_font_family_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_user_agent_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_zoom_text_only_trampoline<P>(this: *mut ffi::WebKitSettings, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Settings> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&Settings::from_glib_borrow(this).downcast_unchecked())
 }
diff --git a/src/auto/uri_request.rs b/src/auto/uri_request.rs
index 97a8ddfd..a00fd89e 100644
--- a/src/auto/uri_request.rs
+++ b/src/auto/uri_request.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
@@ -81,6 +81,7 @@ impl<O: IsA<URIRequest> + IsA<glib::object::Object>> URIRequestExt for O {
 
 unsafe extern "C" fn notify_uri_trampoline<P>(this: *mut ffi::WebKitURIRequest, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<URIRequest> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&URIRequest::from_glib_borrow(this).downcast_unchecked())
 }
diff --git a/src/auto/uri_response.rs b/src/auto/uri_response.rs
index 0b53a54f..e76559ae 100644
--- a/src/auto/uri_response.rs
+++ b/src/auto/uri_response.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
@@ -140,6 +140,7 @@ impl<O: IsA<URIResponse> + IsA<glib::object::Object>> URIResponseExt for O {
 
 unsafe extern "C" fn notify_content_length_trampoline<P>(this: *mut ffi::WebKitURIResponse, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<URIResponse> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&URIResponse::from_glib_borrow(this).downcast_unchecked())
 }
@@ -147,30 +148,35 @@ where P: IsA<URIResponse> {
 #[cfg(any(feature = "v2_6", feature = "dox"))]
 unsafe extern "C" fn notify_http_headers_trampoline<P>(this: *mut ffi::WebKitURIResponse, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<URIResponse> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&URIResponse::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_mime_type_trampoline<P>(this: *mut ffi::WebKitURIResponse, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<URIResponse> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&URIResponse::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_status_code_trampoline<P>(this: *mut ffi::WebKitURIResponse, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<URIResponse> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&URIResponse::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_suggested_filename_trampoline<P>(this: *mut ffi::WebKitURIResponse, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<URIResponse> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&URIResponse::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_uri_trampoline<P>(this: *mut ffi::WebKitURIResponse, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<URIResponse> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&URIResponse::from_glib_borrow(this).downcast_unchecked())
 }
diff --git a/src/auto/uri_scheme_request.rs b/src/auto/uri_scheme_request.rs
index 9fcfb01c..ede8335e 100644
--- a/src/auto/uri_scheme_request.rs
+++ b/src/auto/uri_scheme_request.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
diff --git a/src/auto/user_content_manager.rs b/src/auto/user_content_manager.rs
index fa3e69d3..24581a4a 100644
--- a/src/auto/user_content_manager.rs
+++ b/src/auto/user_content_manager.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
@@ -131,6 +131,7 @@ impl<O: IsA<UserContentManager> + IsA<glib::object::Object>> UserContentManagerE
 #[cfg(any(feature = "v2_8", feature = "dox"))]
 unsafe extern "C" fn script_message_received_trampoline<P>(this: *mut ffi::WebKitUserContentManager, js_result: *mut ffi::WebKitJavascriptResult, f: glib_ffi::gpointer)
 where P: IsA<UserContentManager> {
+    callback_guard!();
     let f: &&(Fn(&P, &JavascriptResult) + 'static) = transmute(f);
     f(&UserContentManager::from_glib_borrow(this).downcast_unchecked(), &from_glib_borrow(js_result))
 }
diff --git a/src/auto/user_media_permission_request.rs b/src/auto/user_media_permission_request.rs
index d072f972..7ff8f40a 100644
--- a/src/auto/user_media_permission_request.rs
+++ b/src/auto/user_media_permission_request.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
@@ -73,12 +73,14 @@ impl<O: IsA<UserMediaPermissionRequest> + IsA<glib::object::Object>> UserMediaPe
 
 unsafe extern "C" fn notify_is_for_audio_device_trampoline<P>(this: *mut ffi::WebKitUserMediaPermissionRequest, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<UserMediaPermissionRequest> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&UserMediaPermissionRequest::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_is_for_video_device_trampoline<P>(this: *mut ffi::WebKitUserMediaPermissionRequest, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<UserMediaPermissionRequest> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&UserMediaPermissionRequest::from_glib_borrow(this).downcast_unchecked())
 }
diff --git a/src/auto/user_script.rs b/src/auto/user_script.rs
index 00d18040..b5c88948 100644
--- a/src/auto/user_script.rs
+++ b/src/auto/user_script.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
diff --git a/src/auto/user_style_sheet.rs b/src/auto/user_style_sheet.rs
index 7614acd7..c9b972ca 100644
--- a/src/auto/user_style_sheet.rs
+++ b/src/auto/user_style_sheet.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
diff --git a/src/auto/web_context.rs b/src/auto/web_context.rs
index d282004c..1e5404c1 100644
--- a/src/auto/web_context.rs
+++ b/src/auto/web_context.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
@@ -453,6 +453,7 @@ impl<O: IsA<WebContext> + IsA<glib::object::Object>> WebContextExt for O {
 
 unsafe extern "C" fn download_started_trampoline<P>(this: *mut ffi::WebKitWebContext, download: *mut ffi::WebKitDownload, f: glib_ffi::gpointer)
 where P: IsA<WebContext> {
+    callback_guard!();
     let f: &&(Fn(&P, &Download) + 'static) = transmute(f);
     f(&WebContext::from_glib_borrow(this).downcast_unchecked(), &from_glib_borrow(download))
 }
@@ -460,6 +461,7 @@ where P: IsA<WebContext> {
 #[cfg(any(feature = "v2_16", feature = "dox"))]
 unsafe extern "C" fn initialize_notification_permissions_trampoline<P>(this: *mut ffi::WebKitWebContext, f: glib_ffi::gpointer)
 where P: IsA<WebContext> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebContext::from_glib_borrow(this).downcast_unchecked())
 }
@@ -467,6 +469,7 @@ where P: IsA<WebContext> {
 #[cfg(any(feature = "v2_4", feature = "dox"))]
 unsafe extern "C" fn initialize_web_extensions_trampoline<P>(this: *mut ffi::WebKitWebContext, f: glib_ffi::gpointer)
 where P: IsA<WebContext> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebContext::from_glib_borrow(this).downcast_unchecked())
 }
@@ -474,6 +477,7 @@ where P: IsA<WebContext> {
 #[cfg(any(feature = "v2_8", feature = "dox"))]
 unsafe extern "C" fn notify_local_storage_directory_trampoline<P>(this: *mut ffi::WebKitWebContext, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WebContext> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebContext::from_glib_borrow(this).downcast_unchecked())
 }
@@ -481,6 +485,7 @@ where P: IsA<WebContext> {
 #[cfg(any(feature = "v2_10", feature = "dox"))]
 unsafe extern "C" fn notify_website_data_manager_trampoline<P>(this: *mut ffi::WebKitWebContext, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WebContext> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebContext::from_glib_borrow(this).downcast_unchecked())
 }
diff --git a/src/auto/web_inspector.rs b/src/auto/web_inspector.rs
index 78c2ed8e..94377641 100644
--- a/src/auto/web_inspector.rs
+++ b/src/auto/web_inspector.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
@@ -187,36 +187,42 @@ impl<O: IsA<WebInspector> + IsA<glib::object::Object>> WebInspectorExt for O {
 
 unsafe extern "C" fn attach_trampoline<P>(this: *mut ffi::WebKitWebInspector, f: glib_ffi::gpointer) -> glib_ffi::gboolean
 where P: IsA<WebInspector> {
+    callback_guard!();
     let f: &&(Fn(&P) -> bool + 'static) = transmute(f);
     f(&WebInspector::from_glib_borrow(this).downcast_unchecked()).to_glib()
 }
 
 unsafe extern "C" fn bring_to_front_trampoline<P>(this: *mut ffi::WebKitWebInspector, f: glib_ffi::gpointer) -> glib_ffi::gboolean
 where P: IsA<WebInspector> {
+    callback_guard!();
     let f: &&(Fn(&P) -> bool + 'static) = transmute(f);
     f(&WebInspector::from_glib_borrow(this).downcast_unchecked()).to_glib()
 }
 
 unsafe extern "C" fn closed_trampoline<P>(this: *mut ffi::WebKitWebInspector, f: glib_ffi::gpointer)
 where P: IsA<WebInspector> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebInspector::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn detach_trampoline<P>(this: *mut ffi::WebKitWebInspector, f: glib_ffi::gpointer) -> glib_ffi::gboolean
 where P: IsA<WebInspector> {
+    callback_guard!();
     let f: &&(Fn(&P) -> bool + 'static) = transmute(f);
     f(&WebInspector::from_glib_borrow(this).downcast_unchecked()).to_glib()
 }
 
 unsafe extern "C" fn open_window_trampoline<P>(this: *mut ffi::WebKitWebInspector, f: glib_ffi::gpointer) -> glib_ffi::gboolean
 where P: IsA<WebInspector> {
+    callback_guard!();
     let f: &&(Fn(&P) -> bool + 'static) = transmute(f);
     f(&WebInspector::from_glib_borrow(this).downcast_unchecked()).to_glib()
 }
 
 unsafe extern "C" fn notify_attached_height_trampoline<P>(this: *mut ffi::WebKitWebInspector, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WebInspector> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebInspector::from_glib_borrow(this).downcast_unchecked())
 }
@@ -224,12 +230,14 @@ where P: IsA<WebInspector> {
 #[cfg(any(feature = "v2_8", feature = "dox"))]
 unsafe extern "C" fn notify_can_attach_trampoline<P>(this: *mut ffi::WebKitWebInspector, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WebInspector> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebInspector::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_inspected_uri_trampoline<P>(this: *mut ffi::WebKitWebInspector, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WebInspector> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebInspector::from_glib_borrow(this).downcast_unchecked())
 }
diff --git a/src/auto/web_resource.rs b/src/auto/web_resource.rs
index dfe7c9c2..5a8ce15f 100644
--- a/src/auto/web_resource.rs
+++ b/src/auto/web_resource.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
@@ -131,6 +131,7 @@ impl<O: IsA<WebResource> + IsA<glib::object::Object>> WebResourceExt for O {
 
 unsafe extern "C" fn failed_trampoline<P>(this: *mut ffi::WebKitWebResource, error: *mut glib_ffi::GError, f: glib_ffi::gpointer)
 where P: IsA<WebResource> {
+    callback_guard!();
     let f: &&(Fn(&P, &Error) + 'static) = transmute(f);
     f(&WebResource::from_glib_borrow(this).downcast_unchecked(), &from_glib_borrow(error))
 }
@@ -138,36 +139,42 @@ where P: IsA<WebResource> {
 #[cfg(any(feature = "v2_8", feature = "dox"))]
 unsafe extern "C" fn failed_with_tls_errors_trampoline<P>(this: *mut ffi::WebKitWebResource, certificate: *mut gio_ffi::GTlsCertificate, errors: gio_ffi::GTlsCertificateFlags, f: glib_ffi::gpointer)
 where P: IsA<WebResource> {
+    callback_guard!();
     let f: &&(Fn(&P, &gio::TlsCertificate, gio::TlsCertificateFlags) + 'static) = transmute(f);
     f(&WebResource::from_glib_borrow(this).downcast_unchecked(), &from_glib_borrow(certificate), from_glib(errors))
 }
 
 unsafe extern "C" fn finished_trampoline<P>(this: *mut ffi::WebKitWebResource, f: glib_ffi::gpointer)
 where P: IsA<WebResource> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebResource::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn received_data_trampoline<P>(this: *mut ffi::WebKitWebResource, data_length: u64, f: glib_ffi::gpointer)
 where P: IsA<WebResource> {
+    callback_guard!();
     let f: &&(Fn(&P, u64) + 'static) = transmute(f);
     f(&WebResource::from_glib_borrow(this).downcast_unchecked(), data_length)
 }
 
 unsafe extern "C" fn sent_request_trampoline<P>(this: *mut ffi::WebKitWebResource, request: *mut ffi::WebKitURIRequest, redirected_response: *mut ffi::WebKitURIResponse, f: glib_ffi::gpointer)
 where P: IsA<WebResource> {
+    callback_guard!();
     let f: &&(Fn(&P, &URIRequest, &URIResponse) + 'static) = transmute(f);
     f(&WebResource::from_glib_borrow(this).downcast_unchecked(), &from_glib_borrow(request), &from_glib_borrow(redirected_response))
 }
 
 unsafe extern "C" fn notify_response_trampoline<P>(this: *mut ffi::WebKitWebResource, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WebResource> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebResource::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_uri_trampoline<P>(this: *mut ffi::WebKitWebResource, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WebResource> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebResource::from_glib_borrow(this).downcast_unchecked())
 }
diff --git a/src/auto/web_view.rs b/src/auto/web_view.rs
index 131bc311..d44be16d 100644
--- a/src/auto/web_view.rs
+++ b/src/auto/web_view.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
@@ -1101,24 +1101,28 @@ impl<O: IsA<WebView> + IsA<glib::object::Object>> WebViewExt for O {
 #[cfg(any(feature = "v2_2", feature = "dox"))]
 unsafe extern "C" fn authenticate_trampoline<P>(this: *mut ffi::WebKitWebView, request: *mut ffi::WebKitAuthenticationRequest, f: glib_ffi::gpointer) -> glib_ffi::gboolean
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P, &AuthenticationRequest) -> bool + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked(), &from_glib_borrow(request)).to_glib()
 }
 
 unsafe extern "C" fn close_trampoline<P>(this: *mut ffi::WebKitWebView, f: glib_ffi::gpointer)
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn context_menu_trampoline<P>(this: *mut ffi::WebKitWebView, context_menu: *mut ffi::WebKitContextMenu, event: *mut gdk_ffi::GdkEvent, hit_test_result: *mut ffi::WebKitHitTestResult, f: glib_ffi::gpointer) -> glib_ffi::gboolean
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P, &ContextMenu, &gdk::Event, &HitTestResult) -> bool + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked(), &from_glib_borrow(context_menu), &from_glib_none(event), &from_glib_borrow(hit_test_result)).to_glib()
 }
 
 unsafe extern "C" fn context_menu_dismissed_trampoline<P>(this: *mut ffi::WebKitWebView, f: glib_ffi::gpointer)
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked())
 }
@@ -1126,42 +1130,49 @@ where P: IsA<WebView> {
 #[cfg(any(feature = "v2_6", feature = "dox"))]
 unsafe extern "C" fn create_trampoline<P>(this: *mut ffi::WebKitWebView, navigation_action: *mut ffi::WebKitNavigationAction, f: glib_ffi::gpointer) -> *mut gtk_ffi::GtkWidget
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P, &NavigationAction) -> Option<gtk::Widget> + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked(), &from_glib_borrow(navigation_action)).to_glib_full()
 }
 
 unsafe extern "C" fn decide_policy_trampoline<P>(this: *mut ffi::WebKitWebView, decision: *mut ffi::WebKitPolicyDecision, decision_type: ffi::WebKitPolicyDecisionType, f: glib_ffi::gpointer) -> glib_ffi::gboolean
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P, &PolicyDecision, PolicyDecisionType) -> bool + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked(), &from_glib_borrow(decision), from_glib(decision_type)).to_glib()
 }
 
 unsafe extern "C" fn enter_fullscreen_trampoline<P>(this: *mut ffi::WebKitWebView, f: glib_ffi::gpointer) -> glib_ffi::gboolean
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P) -> bool + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked()).to_glib()
 }
 
 unsafe extern "C" fn insecure_content_detected_trampoline<P>(this: *mut ffi::WebKitWebView, event: ffi::WebKitInsecureContentEvent, f: glib_ffi::gpointer)
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P, InsecureContentEvent) + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked(), from_glib(event))
 }
 
 unsafe extern "C" fn leave_fullscreen_trampoline<P>(this: *mut ffi::WebKitWebView, f: glib_ffi::gpointer) -> glib_ffi::gboolean
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P) -> bool + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked()).to_glib()
 }
 
 unsafe extern "C" fn load_changed_trampoline<P>(this: *mut ffi::WebKitWebView, load_event: ffi::WebKitLoadEvent, f: glib_ffi::gpointer)
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P, LoadEvent) + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked(), from_glib(load_event))
 }
 
 unsafe extern "C" fn load_failed_trampoline<P>(this: *mut ffi::WebKitWebView, load_event: ffi::WebKitLoadEvent, failing_uri: *mut libc::c_char, error: *mut glib_ffi::GError, f: glib_ffi::gpointer) -> glib_ffi::gboolean
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P, LoadEvent, &str, &Error) -> bool + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked(), from_glib(load_event), &String::from_glib_none(failing_uri), &from_glib_borrow(error)).to_glib()
 }
@@ -1169,42 +1180,49 @@ where P: IsA<WebView> {
 #[cfg(any(feature = "v2_6", feature = "dox"))]
 unsafe extern "C" fn load_failed_with_tls_errors_trampoline<P>(this: *mut ffi::WebKitWebView, failing_uri: *mut libc::c_char, certificate: *mut gio_ffi::GTlsCertificate, errors: gio_ffi::GTlsCertificateFlags, f: glib_ffi::gpointer) -> glib_ffi::gboolean
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P, &str, &gio::TlsCertificate, gio::TlsCertificateFlags) -> bool + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked(), &String::from_glib_none(failing_uri), &from_glib_borrow(certificate), from_glib(errors)).to_glib()
 }
 
 unsafe extern "C" fn mouse_target_changed_trampoline<P>(this: *mut ffi::WebKitWebView, hit_test_result: *mut ffi::WebKitHitTestResult, modifiers: libc::c_uint, f: glib_ffi::gpointer)
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P, &HitTestResult, u32) + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked(), &from_glib_borrow(hit_test_result), modifiers)
 }
 
 unsafe extern "C" fn permission_request_trampoline<P>(this: *mut ffi::WebKitWebView, request: *mut ffi::WebKitPermissionRequest, f: glib_ffi::gpointer) -> glib_ffi::gboolean
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P, &PermissionRequest) -> bool + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked(), &from_glib_borrow(request)).to_glib()
 }
 
 unsafe extern "C" fn print_trampoline<P>(this: *mut ffi::WebKitWebView, print_operation: *mut ffi::WebKitPrintOperation, f: glib_ffi::gpointer) -> glib_ffi::gboolean
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P, &PrintOperation) -> bool + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked(), &from_glib_borrow(print_operation)).to_glib()
 }
 
 unsafe extern "C" fn ready_to_show_trampoline<P>(this: *mut ffi::WebKitWebView, f: glib_ffi::gpointer)
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn resource_load_started_trampoline<P>(this: *mut ffi::WebKitWebView, resource: *mut ffi::WebKitWebResource, request: *mut ffi::WebKitURIRequest, f: glib_ffi::gpointer)
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P, &WebResource, &URIRequest) + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked(), &from_glib_borrow(resource), &from_glib_borrow(request))
 }
 
 unsafe extern "C" fn run_as_modal_trampoline<P>(this: *mut ffi::WebKitWebView, f: glib_ffi::gpointer)
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked())
 }
@@ -1212,18 +1230,21 @@ where P: IsA<WebView> {
 #[cfg(any(feature = "v2_8", feature = "dox"))]
 unsafe extern "C" fn run_color_chooser_trampoline<P>(this: *mut ffi::WebKitWebView, request: *mut ffi::WebKitColorChooserRequest, f: glib_ffi::gpointer) -> glib_ffi::gboolean
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P, &ColorChooserRequest) -> bool + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked(), &from_glib_borrow(request)).to_glib()
 }
 
 unsafe extern "C" fn run_file_chooser_trampoline<P>(this: *mut ffi::WebKitWebView, request: *mut ffi::WebKitFileChooserRequest, f: glib_ffi::gpointer) -> glib_ffi::gboolean
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P, &FileChooserRequest) -> bool + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked(), &from_glib_borrow(request)).to_glib()
 }
 
 unsafe extern "C" fn script_dialog_trampoline<P>(this: *mut ffi::WebKitWebView, dialog: *mut ffi::WebKitScriptDialog, f: glib_ffi::gpointer) -> glib_ffi::gboolean
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P, &ScriptDialog) -> bool + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked(), &from_glib_borrow(dialog)).to_glib()
 }
@@ -1231,18 +1252,21 @@ where P: IsA<WebView> {
 #[cfg(any(feature = "v2_8", feature = "dox"))]
 unsafe extern "C" fn show_notification_trampoline<P>(this: *mut ffi::WebKitWebView, notification: *mut ffi::WebKitNotification, f: glib_ffi::gpointer) -> glib_ffi::gboolean
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P, &Notification) -> bool + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked(), &from_glib_borrow(notification)).to_glib()
 }
 
 unsafe extern "C" fn submit_form_trampoline<P>(this: *mut ffi::WebKitWebView, request: *mut ffi::WebKitFormSubmissionRequest, f: glib_ffi::gpointer)
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P, &FormSubmissionRequest) + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked(), &from_glib_borrow(request))
 }
 
 unsafe extern "C" fn web_process_crashed_trampoline<P>(this: *mut ffi::WebKitWebView, f: glib_ffi::gpointer) -> glib_ffi::gboolean
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P) -> bool + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked()).to_glib()
 }
@@ -1250,18 +1274,21 @@ where P: IsA<WebView> {
 #[cfg(any(feature = "v2_8", feature = "dox"))]
 unsafe extern "C" fn notify_editable_trampoline<P>(this: *mut ffi::WebKitWebView, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_estimated_load_progress_trampoline<P>(this: *mut ffi::WebKitWebView, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_favicon_trampoline<P>(this: *mut ffi::WebKitWebView, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked())
 }
@@ -1269,6 +1296,7 @@ where P: IsA<WebView> {
 #[cfg(any(feature = "v2_18", feature = "dox"))]
 unsafe extern "C" fn notify_is_controlled_by_automation_trampoline<P>(this: *mut ffi::WebKitWebView, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked())
 }
@@ -1276,12 +1304,14 @@ where P: IsA<WebView> {
 #[cfg(any(feature = "v2_16", feature = "dox"))]
 unsafe extern "C" fn notify_is_ephemeral_trampoline<P>(this: *mut ffi::WebKitWebView, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_is_loading_trampoline<P>(this: *mut ffi::WebKitWebView, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked())
 }
@@ -1289,6 +1319,7 @@ where P: IsA<WebView> {
 #[cfg(any(feature = "v2_8", feature = "dox"))]
 unsafe extern "C" fn notify_is_playing_audio_trampoline<P>(this: *mut ffi::WebKitWebView, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked())
 }
@@ -1296,6 +1327,7 @@ where P: IsA<WebView> {
 #[cfg(any(feature = "v2_4", feature = "dox"))]
 unsafe extern "C" fn notify_related_view_trampoline<P>(this: *mut ffi::WebKitWebView, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked())
 }
@@ -1303,18 +1335,21 @@ where P: IsA<WebView> {
 #[cfg(any(feature = "v2_6", feature = "dox"))]
 unsafe extern "C" fn notify_settings_trampoline<P>(this: *mut ffi::WebKitWebView, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_title_trampoline<P>(this: *mut ffi::WebKitWebView, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_uri_trampoline<P>(this: *mut ffi::WebKitWebView, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked())
 }
@@ -1322,18 +1357,21 @@ where P: IsA<WebView> {
 #[cfg(any(feature = "v2_6", feature = "dox"))]
 unsafe extern "C" fn notify_user_content_manager_trampoline<P>(this: *mut ffi::WebKitWebView, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_web_context_trampoline<P>(this: *mut ffi::WebKitWebView, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_zoom_level_trampoline<P>(this: *mut ffi::WebKitWebView, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WebView> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebView::from_glib_borrow(this).downcast_unchecked())
 }
diff --git a/src/auto/web_view_base.rs b/src/auto/web_view_base.rs
index 3135bfaa..f678a718 100644
--- a/src/auto/web_view_base.rs
+++ b/src/auto/web_view_base.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
diff --git a/src/auto/web_view_session_state.rs b/src/auto/web_view_session_state.rs
index 89a5abcc..ad7c0483 100644
--- a/src/auto/web_view_session_state.rs
+++ b/src/auto/web_view_session_state.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
diff --git a/src/auto/website_data_manager.rs b/src/auto/website_data_manager.rs
index c311b6fb..3973b19d 100644
--- a/src/auto/website_data_manager.rs
+++ b/src/auto/website_data_manager.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
@@ -279,6 +279,7 @@ impl<O: IsA<WebsiteDataManager> + IsA<glib::object::Object>> WebsiteDataManagerE
 #[cfg(any(feature = "v2_10", feature = "dox"))]
 unsafe extern "C" fn notify_base_cache_directory_trampoline<P>(this: *mut ffi::WebKitWebsiteDataManager, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WebsiteDataManager> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebsiteDataManager::from_glib_borrow(this).downcast_unchecked())
 }
@@ -286,6 +287,7 @@ where P: IsA<WebsiteDataManager> {
 #[cfg(any(feature = "v2_10", feature = "dox"))]
 unsafe extern "C" fn notify_base_data_directory_trampoline<P>(this: *mut ffi::WebKitWebsiteDataManager, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WebsiteDataManager> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebsiteDataManager::from_glib_borrow(this).downcast_unchecked())
 }
@@ -293,6 +295,7 @@ where P: IsA<WebsiteDataManager> {
 #[cfg(any(feature = "v2_10", feature = "dox"))]
 unsafe extern "C" fn notify_disk_cache_directory_trampoline<P>(this: *mut ffi::WebKitWebsiteDataManager, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WebsiteDataManager> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebsiteDataManager::from_glib_borrow(this).downcast_unchecked())
 }
@@ -300,6 +303,7 @@ where P: IsA<WebsiteDataManager> {
 #[cfg(any(feature = "v2_10", feature = "dox"))]
 unsafe extern "C" fn notify_indexeddb_directory_trampoline<P>(this: *mut ffi::WebKitWebsiteDataManager, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WebsiteDataManager> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebsiteDataManager::from_glib_borrow(this).downcast_unchecked())
 }
@@ -307,6 +311,7 @@ where P: IsA<WebsiteDataManager> {
 #[cfg(any(feature = "v2_16", feature = "dox"))]
 unsafe extern "C" fn notify_is_ephemeral_trampoline<P>(this: *mut ffi::WebKitWebsiteDataManager, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WebsiteDataManager> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebsiteDataManager::from_glib_borrow(this).downcast_unchecked())
 }
@@ -314,6 +319,7 @@ where P: IsA<WebsiteDataManager> {
 #[cfg(any(feature = "v2_10", feature = "dox"))]
 unsafe extern "C" fn notify_local_storage_directory_trampoline<P>(this: *mut ffi::WebKitWebsiteDataManager, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WebsiteDataManager> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebsiteDataManager::from_glib_borrow(this).downcast_unchecked())
 }
@@ -321,6 +327,7 @@ where P: IsA<WebsiteDataManager> {
 #[cfg(any(feature = "v2_10", feature = "dox"))]
 unsafe extern "C" fn notify_offline_application_cache_directory_trampoline<P>(this: *mut ffi::WebKitWebsiteDataManager, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WebsiteDataManager> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebsiteDataManager::from_glib_borrow(this).downcast_unchecked())
 }
@@ -328,6 +335,7 @@ where P: IsA<WebsiteDataManager> {
 #[cfg(any(feature = "v2_10", feature = "dox"))]
 unsafe extern "C" fn notify_websql_directory_trampoline<P>(this: *mut ffi::WebKitWebsiteDataManager, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WebsiteDataManager> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WebsiteDataManager::from_glib_borrow(this).downcast_unchecked())
 }
diff --git a/src/auto/window_properties.rs b/src/auto/window_properties.rs
index c57ad357..23ba3b8f 100644
--- a/src/auto/window_properties.rs
+++ b/src/auto/window_properties.rs
@@ -1,4 +1,4 @@
-// This file was generated by gir (https://github.com/gtk-rs/gir @ 8b9d0bb)
+// This file was generated by gir (https://github.com/gtk-rs/gir @ fbb95f4)
 // from gir-files (https://github.com/gtk-rs/gir-files @ 77d1f70)
 // DO NOT EDIT
 
@@ -177,48 +177,56 @@ impl<O: IsA<WindowProperties> + IsA<glib::object::Object>> WindowPropertiesExt f
 
 unsafe extern "C" fn notify_fullscreen_trampoline<P>(this: *mut ffi::WebKitWindowProperties, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WindowProperties> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WindowProperties::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_geometry_trampoline<P>(this: *mut ffi::WebKitWindowProperties, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WindowProperties> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WindowProperties::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_locationbar_visible_trampoline<P>(this: *mut ffi::WebKitWindowProperties, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WindowProperties> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WindowProperties::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_menubar_visible_trampoline<P>(this: *mut ffi::WebKitWindowProperties, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WindowProperties> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WindowProperties::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_resizable_trampoline<P>(this: *mut ffi::WebKitWindowProperties, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WindowProperties> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WindowProperties::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_scrollbars_visible_trampoline<P>(this: *mut ffi::WebKitWindowProperties, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WindowProperties> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WindowProperties::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_statusbar_visible_trampoline<P>(this: *mut ffi::WebKitWindowProperties, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WindowProperties> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WindowProperties::from_glib_borrow(this).downcast_unchecked())
 }
 
 unsafe extern "C" fn notify_toolbar_visible_trampoline<P>(this: *mut ffi::WebKitWindowProperties, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<WindowProperties> {
+    callback_guard!();
     let f: &&(Fn(&P) + 'static) = transmute(f);
     f(&WindowProperties::from_glib_borrow(this).downcast_unchecked())
 }
diff --git a/src/lib.rs b/src/lib.rs
index 38c444e0..97845c42 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -40,6 +40,12 @@ macro_rules! skip_assert_initialized {
     () => ()
 }
 
+macro_rules! callback_guard {
+    () => (
+        let _guard = ::glib::CallbackGuard::new();
+    )
+}
+
 mod auto;
 mod script_dialog;
 mod web_view;
diff --git a/src/web_view.rs b/src/web_view.rs
index a9e65165..4ff4d6fa 100644
--- a/src/web_view.rs
+++ b/src/web_view.rs
@@ -98,6 +98,7 @@ impl<O> WebViewExtManual for O
 }
 
 unsafe extern "C" fn async_ready_trampoline(this: *mut gobject_ffi::GObject, result: *mut gio_ffi::GAsyncResult, f: glib_ffi::gpointer) {
+    callback_guard!();
     let mut error = ptr::null_mut();
     let javascript_result = ffi::webkit_web_view_run_javascript_finish(this as *mut _, result, &mut error);
     let value =