Basic support for stateless linear collection marshalling (#71473)

Basic stateless linear collection marshalling for blittable elements

Not handled:
- caller-allocated buffer
- guaranteed unmarshal
- pinnable reference
- non-blittable element marshalling
- element scenarios on custom marshallers

1 files changed, 17 insertions, 0 deletions

diff --git a/src/libraries/System.Runtime.InteropServices/tests/Ancillary.Interop/ElementUnmanagedTypeAttribute.cs b/src/libraries/System.Runtime.InteropServices/tests/Ancillary.Interop/ElementUnmanagedTypeAttribute.cs
new file mode 100644
index 00000000000..d0f508904a1
--- /dev/null
+++ b/src/libraries/System.Runtime.InteropServices/tests/Ancillary.Interop/ElementUnmanagedTypeAttribute.cs
@@ -0,0 +1,17 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace System.Runtime.InteropServices.Marshalling
+{
+    /// <summary>
+    /// Specifies that a particular generic parameter is the collection element's unmanaged type.
+    /// </summary>
+    /// <remarks>
+    /// If this attribute is provided on a generic parameter of a marshaller, then the generator will assume
+    /// that it is a linear collection marshaller.
+    /// </remarks>
+    [AttributeUsage(AttributeTargets.GenericParameter)]
+    public sealed class ElementUnmanagedTypeAttribute : Attribute
+    {
+    }
+}