Add nullability to CreateInstance in TypeDescriptor/TypeDescriptionProvider to match Activator.CreateInstance (#79776)

Author: elachlan

src/libraries/System.ComponentModel.TypeConverter/ref/System.ComponentModel.TypeConverter.cs

@@ -1382,7 +1382,7 @@ public abstract partial class TypeDescriptionProvider
     {
         protected TypeDescriptionProvider() { }
         protected TypeDescriptionProvider(System.ComponentModel.TypeDescriptionProvider parent) { }
-        public virtual object? CreateInstance(System.IServiceProvider? provider, [System.Diagnostics.CodeAnalysis.DynamicallyAccessedMembersAttribute(System.Diagnostics.CodeAnalysis.DynamicallyAccessedMemberTypes.PublicConstructors)] System.Type objectType, System.Type[]? argTypes, object[]? args) { throw null; }
+        public virtual object? CreateInstance(System.IServiceProvider? provider, [System.Diagnostics.CodeAnalysis.DynamicallyAccessedMembersAttribute(System.Diagnostics.CodeAnalysis.DynamicallyAccessedMemberTypes.PublicConstructors)] System.Type objectType, System.Type[]? argTypes, object?[]? args) { throw null; }
         public virtual System.Collections.IDictionary? GetCache(object instance) { throw null; }
         [System.Diagnostics.CodeAnalysis.RequiresUnreferencedCodeAttribute("The Type of instance cannot be statically discovered.")]
         public virtual System.ComponentModel.ICustomTypeDescriptor GetExtendedTypeDescriptor(object instance) { throw null; }
@@ -1434,7 +1434,7 @@ public static void CreateAssociation(object primary, object secondary) { }
         public static System.ComponentModel.Design.IDesigner? CreateDesigner(System.ComponentModel.IComponent component, System.Type designerBaseType) { throw null; }
         public static System.ComponentModel.EventDescriptor CreateEvent([System.Diagnostics.CodeAnalysis.DynamicallyAccessedMembersAttribute(System.Diagnostics.CodeAnalysis.DynamicallyAccessedMemberTypes.All)] System.Type componentType, System.ComponentModel.EventDescriptor oldEventDescriptor, params System.Attribute[] attributes) { throw null; }
         public static System.ComponentModel.EventDescriptor CreateEvent([System.Diagnostics.CodeAnalysis.DynamicallyAccessedMembersAttribute(System.Diagnostics.CodeAnalysis.DynamicallyAccessedMemberTypes.All)] System.Type componentType, string name, System.Type type, params System.Attribute[] attributes) { throw null; }
-        public static object? CreateInstance(System.IServiceProvider? provider, [System.Diagnostics.CodeAnalysis.DynamicallyAccessedMembersAttribute(System.Diagnostics.CodeAnalysis.DynamicallyAccessedMemberTypes.PublicConstructors)] System.Type objectType, System.Type[]? argTypes, object[]? args) { throw null; }
+        public static object? CreateInstance(System.IServiceProvider? provider, [System.Diagnostics.CodeAnalysis.DynamicallyAccessedMembersAttribute(System.Diagnostics.CodeAnalysis.DynamicallyAccessedMemberTypes.PublicConstructors)] System.Type objectType, System.Type[]? argTypes, object?[]? args) { throw null; }
         [System.Diagnostics.CodeAnalysis.RequiresUnreferencedCodeAttribute("PropertyDescriptor's PropertyType cannot be statically discovered.")]
         public static System.ComponentModel.PropertyDescriptor CreateProperty([System.Diagnostics.CodeAnalysis.DynamicallyAccessedMembersAttribute(System.Diagnostics.CodeAnalysis.DynamicallyAccessedMemberTypes.All)] System.Type componentType, System.ComponentModel.PropertyDescriptor oldPropertyDescriptor, params System.Attribute[] attributes) { throw null; }
         [System.Diagnostics.CodeAnalysis.RequiresUnreferencedCodeAttribute("PropertyDescriptor's PropertyType cannot be statically discovered.")]

src/libraries/System.ComponentModel.TypeConverter/src/System/ComponentModel/DelegatingTypeDescriptionProvider.cs

@@ -36,7 +36,7 @@ internal DelegatingTypeDescriptionProvider(Type type)
             IServiceProvider? provider,
             [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicConstructors)] Type objectType,
             Type[]? argTypes,
-            object[]? args)
+            object?[]? args)
         {
             return Provider.CreateInstance(provider, objectType, argTypes, args);
         }

src/libraries/System.ComponentModel.TypeConverter/src/System/ComponentModel/ReflectTypeDescriptionProvider.cs

@@ -260,7 +260,7 @@ internal static void AddEditorTable(Type editorBaseType, Hashtable table)
             IServiceProvider? provider,
             [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicConstructors)] Type objectType,
             Type[]? argTypes,
-            object[]? args)
+            object?[]? args)
         {
             Debug.Assert(objectType != null, "Should have arg-checked before coming in here");
 
@@ -277,9 +277,9 @@ internal static void AddEditorTable(Type editorBaseType, Hashtable table)
                     argTypes = new Type[args.Length];
                     for (int idx = 0; idx < args.Length; idx++)
                     {
-                        if (args[idx] != null)
+                        if (args[idx] is object arg)
                         {
-                            argTypes[idx] = args[idx].GetType();
+                            argTypes[idx] = arg.GetType();
                         }
                         else
                         {

src/libraries/System.ComponentModel.TypeConverter/src/System/ComponentModel/TypeDescriptionProvider.cs

@@ -54,7 +54,7 @@ protected TypeDescriptionProvider(TypeDescriptionProvider parent)
             IServiceProvider? provider,
             [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicConstructors)] Type objectType,
             Type[]? argTypes,
-            object[]? args)
+            object?[]? args)
         {
             if (_parent != null)
             {

src/libraries/System.ComponentModel.TypeConverter/src/System/ComponentModel/TypeDescriptor.cs

@@ -395,7 +395,7 @@ public static EventDescriptor CreateEvent(
             IServiceProvider? provider,
             [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicConstructors)] Type objectType,
             Type[]? argTypes,
-            object[]? args)
+            object?[]? args)
         {
             ArgumentNullException.ThrowIfNull(objectType);
 
@@ -3015,7 +3015,7 @@ internal TypeDescriptionNode(TypeDescriptionProvider provider)
                 IServiceProvider? provider,
                 [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicConstructors)] Type objectType,
                 Type[]? argTypes,
-                object[]? args)
+                object?[]? args)
             {
                 ArgumentNullException.ThrowIfNull(objectType);