[AppKit] Fix return type for NSStoryboard.InstantiateController / InstantiateInitialController. Fixes #23373. (#23400)

These two methods were bound with the wrong return type.

Unfortunately there's no nice way of fixing APIs with the wrong return type,
so there was no pretty way to do it.

Fixes #23373.

Author: rolfbjarne

src/appkit.cs

@@ -18422,12 +18422,57 @@ interface NSStoryboard {
 		[NullAllowed, Export ("mainStoryboard", ArgumentSemantic.Strong)]
 		NSStoryboard MainStoryboard { get; }
 
+#if !XAMCORE_5_0
+		// Bound using the wrong return type, fix like this so that consuming code will work through breaking changes as long as warnings are fixed:
+		// * Add a '2' variant for !XAMCORE_5_0 with the correct return type
+		// * Obsolete the original variant in !XAMCORE_5_0 (with the wrong return type)
+		// * Obsolete the '2' variant for XAMCORE_5_0 (with the correct return type, but ugly name)
+		// * Make the original variant have the correct return type in XAMCORE_5_0
+		// * Remove the '2' variant in XAMCORE_6_0
+		[Obsolete ("Use 'InstantiateInitialController2' instead.")]
+#endif
 		[Export ("instantiateInitialControllerWithCreator:")]
 		[return: NullAllowed]
+#if XAMCORE_5_0
+		NSObject InstantiateInitialController ([NullAllowed] NSStoryboardControllerCreator handler);
+#else
 		NSViewController InstantiateInitialController ([NullAllowed] NSStoryboardControllerCreator handler);
+#endif
 
+#if !XAMCORE_5_0
+		// Bound using the wrong return type, fix like this so that consuming code will work through breaking changes as long as warnings are fixed:
+		// * Add a '2' variant for !XAMCORE_5_0 with the correct return type
+		// * Obsolete the original variant in !XAMCORE_5_0 (with the wrong return type)
+		// * Obsolete the '2' variant for XAMCORE_5_0 (with the correct return type, but ugly name)
+		// * Make the original variant have the correct return type in XAMCORE_5_0
+		// * Remove the '2' variant in XAMCORE_6_0
+		[Obsolete ("Use 'InstantiateController2' instead.")]
+#endif // !XAMCORE_5_0
 		[Export ("instantiateControllerWithIdentifier:creator:")]
+#if XAMCORE_5_0
+		NSObject InstantiateController (string identifier, [NullAllowed] NSStoryboardControllerCreator handler);
+#else
 		NSViewController InstantiateController (string identifier, [NullAllowed] NSStoryboardControllerCreator handler);
+#endif
+
+#if !XAMCORE_6_0
+#if XAMCORE_5_0
+		[Obsolete ("Use 'InstantiateController' instead.")]
+#else
+		[Sealed]
+#endif // XAMCORE_5_0
+		[Export ("instantiateInitialControllerWithCreator:")]
+		[return: NullAllowed]
+		NSObject InstantiateInitialController2 ([NullAllowed] NSStoryboardControllerCreator handler);
+
+#if XAMCORE_5_0
+		[Obsolete ("Use 'InstantiateController' instead.")]
+#else
+		[Sealed]
+#endif // XAMCORE_5_0
+		[Export ("instantiateControllerWithIdentifier:creator:")]
+		NSObject InstantiateController2 (string identifier, [NullAllowed] NSStoryboardControllerCreator handler);
+#endif // XAMCORE_6_0
 	}
 
 	[NoMacCatalyst]

tests/cecil-tests/Documentation.KnownFailures.txt

@@ -7894,6 +7894,8 @@ M:AppKit.NSStatusItem.add_DoubleClick(System.EventHandler)
 M:AppKit.NSStatusItem.Dispose(System.Boolean)
 M:AppKit.NSStatusItem.remove_DoubleClick(System.EventHandler)
 M:AppKit.NSStepperTouchBarItem.Dispose(System.Boolean)
+M:AppKit.NSStoryboard.InstantiateController2(System.String,AppKit.NSStoryboardControllerCreator)
+M:AppKit.NSStoryboard.InstantiateInitialController2(AppKit.NSStoryboardControllerCreator)
 M:AppKit.NSStringAttributes.SetStrikethroughStyle(Foundation.NSUnderlineStyle,AppKit.NSUnderlinePattern,System.Boolean)
 M:AppKit.NSStringAttributes.SetUnderlineStyle(Foundation.NSUnderlineStyle,AppKit.NSUnderlinePattern,System.Boolean)
 M:AppKit.NSTableCellView.Dispose(System.Boolean)