Fix ILegacyIAccessibleProvider.GetSelection return type (#3231)

src/System.Windows.Forms.Primitives/src/Interop/UiaCore/Interop.ILegacyIAccessibleProvider.cs

@@ -39,7 +39,8 @@ internal static partial class Interop
 
             string? KeyboardShortcut { get; }
 
-            object[]? /* IRawElementProviderSimple[] */ GetSelection();
+            [return: MarshalAs(UnmanagedType.SafeArray, SafeArraySubType = VarEnum.VT_UNKNOWN)]
+            IRawElementProviderSimple[] GetSelection();
 
             string? DefaultAction { get; }
         }

src/System.Windows.Forms.Primitives/src/Interop/UiaCore/Interop.IRawElementProviderHwndOverride.cs

@@ -15,7 +15,7 @@ internal static partial class Interop
         /// </summary>
         [Guid("1d5df27c-8947-4425-b8d9-79787bb460b8")]
         [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
-        public interface IRawElementProviderHwndOverride : IRawElementProviderSimple
+        public interface IRawElementProviderHwndOverride
         {
             /// <summary>
             ///  Request a provider for the specified component. The returned provider can supply additional

src/System.Windows.Forms/src/System/Windows/Forms/AccessibleObject.cs

@@ -831,14 +831,14 @@ namespace System.Windows.Forms
 
         IAccessible? UiaCore.ILegacyIAccessibleProvider.GetIAccessible() => AsIAccessible(this);
 
-        object[]? UiaCore.ILegacyIAccessibleProvider.GetSelection()
+        UiaCore.IRawElementProviderSimple[] UiaCore.ILegacyIAccessibleProvider.GetSelection()
         {
             if (GetSelected() is UiaCore.IRawElementProviderSimple selected)
             {
                 return new UiaCore.IRawElementProviderSimple[] { selected };
             }
 
-            return null;
+            return Array.Empty<UiaCore.IRawElementProviderSimple>();
         }
 
         void UiaCore.ILegacyIAccessibleProvider.Select(int flagsSelect) => Select((AccessibleSelection)flagsSelect);

src/System.Windows.Forms/src/System/Windows/Forms/InternalAccessibleObject.cs

@@ -400,20 +400,16 @@ namespace System.Windows.Forms
 
         int ILegacyIAccessibleProvider.ChildId => publicILegacyIAccessibleProvider.ChildId;
 
-        void ILegacyIAccessibleProvider.DoDefaultAction()
-            => publicILegacyIAccessibleProvider.DoDefaultAction();
+        void ILegacyIAccessibleProvider.DoDefaultAction() => publicILegacyIAccessibleProvider.DoDefaultAction();
 
         IAccessible? ILegacyIAccessibleProvider.GetIAccessible()
             => publicILegacyIAccessibleProvider.GetIAccessible();
 
-        object[]? ILegacyIAccessibleProvider.GetSelection()
-            => AsArrayOfNativeAccessibles(publicILegacyIAccessibleProvider.GetSelection());
+        IRawElementProviderSimple[] ILegacyIAccessibleProvider.GetSelection() => publicILegacyIAccessibleProvider.GetSelection();
 
-        void ILegacyIAccessibleProvider.Select(int flagsSelect)
-            => publicILegacyIAccessibleProvider.Select(flagsSelect);
+        void ILegacyIAccessibleProvider.Select(int flagsSelect) => publicILegacyIAccessibleProvider.Select(flagsSelect);
 
-        void ILegacyIAccessibleProvider.SetValue(string szValue)
-            => publicILegacyIAccessibleProvider.SetValue(szValue);
+        void ILegacyIAccessibleProvider.SetValue(string szValue) => publicILegacyIAccessibleProvider.SetValue(szValue);
 
         void IInvokeProvider.Invoke() => publicIInvokeProvider.Invoke();