Mark Array.Initialize() with [RequiresUnreferencedCode]

src/coreclr/System.Private.CoreLib/src/System/Array.CoreCLR.cs

@@ -315,6 +315,7 @@ private unsafe bool IsValueOfElementType(object value)
         // if this is an array of value classes and that value class has a default constructor
         // then this calls this default constructor on every element in the value class array.
         // otherwise this is a no-op.  Generally this method is called automatically by the compiler
+        [RequiresUnreferencedCode("The default constructor of the array's element type may be trimmed if not referenced elsewhere.")]
         public unsafe void Initialize()
         {
             MethodTable* pArrayMT = RuntimeHelpers.GetMethodTable(this);

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

@@ -253,6 +253,7 @@ internal static unsafe Array CtorRare(MethodTable* pEEType, int nDimensions, int
             }
         }
 
+        [RequiresUnreferencedCode("The default constructor of the array's element type may be trimmed if not referenced elsewhere.")]
         public unsafe void Initialize()
         {
             MethodTable* pElementEEType = ElementMethodTable;

src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/PrimitiveDataContract.cs

@@ -921,6 +921,7 @@ internal NMTOKENSDataContract() : base(DictionaryGlobals.NMTOKENSLocalName, Dict
 
     internal sealed class ByteArrayDataContract : PrimitiveDataContract
     {
+        [RequiresUnreferencedCode("The default constructor of the array's element type may be trimmed if not referenced elsewhere.")]
         public ByteArrayDataContract() : base(typeof(byte[]), DictionaryGlobals.ByteArrayLocalName, DictionaryGlobals.SchemaNamespace)
         {
         }

src/libraries/System.Runtime/ref/System.Runtime.cs

@@ -574,6 +574,7 @@ public static void ForEach<T>(T[] array, System.Action<T> action) { }
         public static int IndexOf<T>(T[] array, T value) { throw null; }
         public static int IndexOf<T>(T[] array, T value, int startIndex) { throw null; }
         public static int IndexOf<T>(T[] array, T value, int startIndex, int count) { throw null; }
+        [System.Diagnostics.CodeAnalysis.RequiresUnreferencedCodeAttribute("The default constructor of the array's element type may be trimmed if not referenced elsewhere.")]
         public void Initialize() { }
         public static int LastIndexOf(System.Array array, object? value) { throw null; }
         public static int LastIndexOf(System.Array array, object? value, int startIndex) { throw null; }

src/mono/System.Private.CoreLib/src/System/Array.Mono.cs

@@ -347,6 +347,7 @@ internal void InternalSetValue(object? value, nint index)
             SetValueImpl(ObjectHandleOnStack.Create(ref self), ObjectHandleOnStack.Create(ref value), (int)index);
         }
 
+        [RequiresUnreferencedCode("The default constructor of the array's element type may be trimmed if not referenced elsewhere.")]
         public void Initialize()
         {
             object arr = this;