[API Proposal]: Create array from array type

src/coreclr/classlibnative/bcltype/arraynative.cpp

@@ -732,7 +732,7 @@ static void CheckElementType(TypeHandle elementType)
             COMPlusThrow(kNotSupportedException, W("NotSupported_ByRefLikeArray"));
 
         // Check for open generic types.
-        if (pMT->IsGenericTypeDefinition() || pMT->ContainsGenericVariables())
+        if (pMT->ContainsGenericVariables())
             COMPlusThrow(kNotSupportedException, W("NotSupported_OpenType"));
 
         // Check for Void.
@@ -765,7 +765,8 @@ void QCALLTYPE Array_CreateInstance(QCall::TypeHandle pTypeHnd, INT32 rank, INT3
         _ASSERTE((INT32)typeHnd.GetRank() == rank);
         _ASSERTE(typeHnd.IsArray());
 
-        CheckElementType(typeHnd.GetArrayElementTypeHandle());
+        if (typeHnd.GetArrayElementTypeHandle().ContainsGenericVariables())
+            COMPlusThrow(kNotSupportedException, W("NotSupported_OpenType"));
 
         if (!typeHnd.AsMethodTable()->IsMultiDimArray())
         {

src/coreclr/nativeaot/System.Private.CoreLib/src/System/Array.NativeAot.cs

@@ -58,7 +58,12 @@ internal unsafe bool IsSzArray
         [RequiresDynamicCode("The code for an array of the specified type might not be available.")]
         private static unsafe Array InternalCreate(RuntimeType elementType, int rank, int* pLengths, int* pLowerBounds)
         {
-            ValidateElementType(elementType);
+            if (elementType.IsByRef || elementType.IsByRefLike)
+                throw new NotSupportedException(SR.NotSupported_ByRefLikeArray);
+            if (elementType == typeof(void))
+                throw new NotSupportedException(SR.NotSupported_VoidArray);
+            if (elementType.ContainsGenericParameters)
+                throw new NotSupportedException(SR.NotSupported_OpenType);
 
             if (pLowerBounds != null)
             {
@@ -93,7 +98,8 @@ private static unsafe Array InternalCreateFromArrayType(RuntimeType arrayType, i
             Debug.Assert(arrayType.IsArray);
             Debug.Assert(arrayType.GetArrayRank() == rank);
 
-            ValidateElementType(arrayType.GetElementType());
+            if (arrayType.ContainsGenericParameters)
+                throw new NotSupportedException(SR.NotSupported_OpenType);
 
             if (pLowerBounds != null)
             {
@@ -125,16 +131,6 @@ private static unsafe Array InternalCreateFromArrayType(RuntimeType arrayType, i
             }
         }
 
-        private static void ValidateElementType(Type elementType)
-        {
-            if (elementType.IsByRef || elementType.IsByRefLike)
-                throw new NotSupportedException(SR.NotSupported_ByRefLikeArray);
-            if (elementType == typeof(void))
-                throw new NotSupportedException(SR.NotSupported_VoidArray);
-            if (elementType.ContainsGenericParameters)
-                throw new NotSupportedException(SR.NotSupported_OpenType);
-        }
-
         public unsafe void Initialize()
         {
             EETypePtr pElementEEType = ElementEEType;

src/libraries/System.Runtime/tests/System.Runtime.Tests/System/ArrayTests.cs

@@ -1826,10 +1826,6 @@ public static unsafe IEnumerable<object[]> CreateInstance_TestData()
                 new object[] { typeof(GenericInterface<int>), default(GenericInterface<int>) },
                 new object[] { typeof(AbstractClass), default(AbstractClass) },
                 new object[] { typeof(StaticClass), default(StaticClass) },
-
-                // Arrays of void arrays
-                new object[] { typeof(void).MakeArrayType(), null },
-                new object[] { typeof(void).MakeArrayType(1), null },
             };
         }
 
@@ -1950,10 +1946,7 @@ public void CreateInstance_NotSupportedType_ThrowsNotSupportedException(Type ele
         }
 
         [Theory]
-        [InlineData(typeof(void))]
         [InlineData(typeof(GenericClass<>))]
-        // not using any by-ref type here as MakeArrayType throws for them, same goes for Type.GetType("SomeByRef[]")	
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/94086", typeof(PlatformDetection), nameof(PlatformDetection.IsMonoRuntime))]
         public void CreateInstanceFromArrayType_NotSupportedArrayType_ThrowsNotSupportedException(Type elementType)
         {
             Assert.Throws<NotSupportedException>(() => Array.CreateInstanceFromArrayType(elementType.MakeArrayType(), 0));