Apply suggestions from code review

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: tannergooding

src/coreclr/nativeaot/System.Private.CoreLib/src/System/Runtime/CompilerServices/RuntimeHelpers.NativeAot.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Diagnostics.CodeAnalysis;
+using System.Numerics;
 using System.Runtime.InteropServices;
 using System.Runtime.Serialization;
 using System.Threading;
@@ -251,9 +252,9 @@ public static unsafe IntPtr AllocateTypeAssociatedMemory(Type type, int size)
         /// <exception cref="ArgumentException"><paramref name="type" /> must be a type provided by the runtime.</exception>
         /// <exception cref="ArgumentOutOfRangeException"><paramref name="size" /> is negative.</exception>
         /// <exception cref="ArgumentException"><paramref name="alignment" /> is not a power of <c>2</c>.</exception>
-        public static IntPtr AllocateTypeAssociatedMemory(Type type, int size, int alignment)
+        public static unsafe IntPtr AllocateTypeAssociatedMemory(Type type, int size, int alignment)
         {
-            if (type is not RuntimeType rt)
+            if (type is not RuntimeType)
             {
                 throw new ArgumentException(SR.Arg_MustBeType, nameof(type));
             }

src/coreclr/vm/runtimehandles.cpp

@@ -1229,7 +1229,7 @@ extern "C" void* QCALLTYPE RuntimeTypeHandle_AlignedAllocateTypeAssociatedMemory
     // that the memory will be freed when the type is unloaded.
     PTR_LoaderAllocator loaderAllocator = typeHandle.GetMethodTable()->GetLoaderAllocator();
     LoaderHeap* loaderHeap = loaderAllocator->GetHighFrequencyHeap();
-    allocatedMemory = loaderHeap->AllocAlignedMem(S_SIZE_T(size), S_SIZE_T(alignment));
+    allocatedMemory = loaderHeap->AllocAlignedMem(S_SIZE_T(size).Value(), S_SIZE_T(alignment).Value());
 
     END_QCALL;
 

src/libraries/System.Runtime/tests/System.Runtime.Tests/System/Runtime/CompilerServices/RuntimeHelpersTests.cs

@@ -457,8 +457,8 @@ public static void AlignedAllocateTypeAssociatedMemoryInvalidArguments()
         {
             Assert.Throws<ArgumentException>(() => { RuntimeHelpers.AllocateTypeAssociatedMemory(null, 10, 1); });
             Assert.Throws<ArgumentOutOfRangeException>(() => { RuntimeHelpers.AllocateTypeAssociatedMemory(typeof(RuntimeHelpersTests), -1, 1); });
-            Assert.Throws<ArgumentException>(() => { RuntimeHelpers.AllocateTypeAssociatedMemory(typeof(RuntimeHelpersTests), -1, 0); });
-            Assert.Throws<ArgumentException>(() => { RuntimeHelpers.AllocateTypeAssociatedMemory(typeof(RuntimeHelpersTests), -1, 3); });
+            Assert.Throws<ArgumentException>(() => { RuntimeHelpers.AllocateTypeAssociatedMemory(typeof(RuntimeHelpersTests), 10, 0); });
+            Assert.Throws<ArgumentException>(() => { RuntimeHelpers.AllocateTypeAssociatedMemory(typeof(RuntimeHelpersTests), 10, 3); });
         }
 
 
@@ -469,6 +469,7 @@ public static unsafe void AlignedAllocateTypeAssociatedMemoryValidArguments()
             Assert.NotEqual(memory, IntPtr.Zero);
             // Validate that the memory is zeroed out
             Assert.True(new Span<byte>((void*)memory, 32).SequenceEqual(new byte[32]));
+            Assert.True((memory % 16) == 0);
         }
 
 #pragma warning disable CS0649

src/mono/System.Private.CoreLib/src/System/Runtime/CompilerServices/RuntimeHelpers.Mono.cs

@@ -4,6 +4,7 @@
 using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
 using System.Diagnostics.Tracing;
+using System.Numerics;
 using System.Runtime.InteropServices;
 using System.Runtime.Serialization;
 
@@ -166,9 +167,9 @@ public static unsafe IntPtr AllocateTypeAssociatedMemory(Type type, int size)
         /// <exception cref="ArgumentException"><paramref name="type" /> must be a type provided by the runtime.</exception>
         /// <exception cref="ArgumentOutOfRangeException"><paramref name="size" /> is negative.</exception>
         /// <exception cref="ArgumentException"><paramref name="alignment" /> is not a power of <c>2</c>.</exception>
-        public static IntPtr AllocateTypeAssociatedMemory(Type type, int size, int alignment)
+        public static unsafe IntPtr AllocateTypeAssociatedMemory(Type type, int size, int alignment)
         {
-            if (type is not RuntimeType rt)
+            if (type is not RuntimeType)
             {
                 throw new ArgumentException(SR.Arg_MustBeType, nameof(type));
             }