From 9c430589e801fa97b2cfb269182452a7d880c3b7 Mon Sep 17 00:00:00 2001
From: Aaron R Robinson <arobins@microsoft.com>
Date: Tue, 12 Sep 2023 21:04:32 -0700
Subject: [PATCH] Update Marshal.QueryInterface() argument modifier

Change "in" modifier to "ref readonly" to avoid warnings
in existing interop code.
---
 .../src/System/Runtime/InteropServices/Marshal.cs               | 2 +-
 .../ref/System.Runtime.InteropServices.cs                       | 2 +-
 .../Runtime/InteropServices/Marshalling/IIUnknownStrategy.cs    | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/libraries/System.Private.CoreLib/src/System/Runtime/InteropServices/Marshal.cs b/src/libraries/System.Private.CoreLib/src/System/Runtime/InteropServices/Marshal.cs
index 98dde70ae362db..11a3319196ad94 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Runtime/InteropServices/Marshal.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Runtime/InteropServices/Marshal.cs
@@ -130,7 +130,7 @@ public static int SizeOf<T>()
             return SizeOfHelper(t, throwIfNotMarshalable: true);
         }
 
-        public static unsafe int QueryInterface(IntPtr pUnk, in Guid iid, out IntPtr ppv)
+        public static unsafe int QueryInterface(IntPtr pUnk, ref readonly Guid iid, out IntPtr ppv)
         {
             ArgumentNullException.ThrowIfNull(pUnk);
 
diff --git a/src/libraries/System.Runtime.InteropServices/ref/System.Runtime.InteropServices.cs b/src/libraries/System.Runtime.InteropServices/ref/System.Runtime.InteropServices.cs
index 8fe3d526ab6e96..59dfcf2713620d 100644
--- a/src/libraries/System.Runtime.InteropServices/ref/System.Runtime.InteropServices.cs
+++ b/src/libraries/System.Runtime.InteropServices/ref/System.Runtime.InteropServices.cs
@@ -1104,7 +1104,7 @@ public static void PtrToStructure(System.IntPtr ptr, object structure) { }
         public static object? PtrToStructure(System.IntPtr ptr, [System.Diagnostics.CodeAnalysis.DynamicallyAccessedMembersAttribute(System.Diagnostics.CodeAnalysis.DynamicallyAccessedMemberTypes.NonPublicConstructors| System.Diagnostics.CodeAnalysis.DynamicallyAccessedMemberTypes.PublicConstructors)] System.Type structureType) { throw null; }
         public static T? PtrToStructure<[System.Diagnostics.CodeAnalysis.DynamicallyAccessedMembersAttribute(System.Diagnostics.CodeAnalysis.DynamicallyAccessedMemberTypes.NonPublicConstructors | System.Diagnostics.CodeAnalysis.DynamicallyAccessedMemberTypes.PublicConstructors)]T>(System.IntPtr ptr) { throw null; }
         public static void PtrToStructure<T>(System.IntPtr ptr, [System.Diagnostics.CodeAnalysis.DisallowNullAttribute] T structure) { }
-        public static int QueryInterface(System.IntPtr pUnk, in System.Guid iid, out System.IntPtr ppv) { throw null; }
+        public static int QueryInterface(System.IntPtr pUnk, ref readonly System.Guid iid, out System.IntPtr ppv) { throw null; }
         public static byte ReadByte(System.IntPtr ptr) { throw null; }
         public static byte ReadByte(System.IntPtr ptr, int ofs) { throw null; }
         [System.Diagnostics.CodeAnalysis.RequiresDynamicCode("Marshalling code for the object might not be available")]
diff --git a/src/libraries/System.Runtime.InteropServices/src/System/Runtime/InteropServices/Marshalling/IIUnknownStrategy.cs b/src/libraries/System.Runtime.InteropServices/src/System/Runtime/InteropServices/Marshalling/IIUnknownStrategy.cs
index 771b88b04e7f4d..aa9742526f3631 100644
--- a/src/libraries/System.Runtime.InteropServices/src/System/Runtime/InteropServices/Marshalling/IIUnknownStrategy.cs
+++ b/src/libraries/System.Runtime.InteropServices/src/System/Runtime/InteropServices/Marshalling/IIUnknownStrategy.cs
@@ -32,7 +32,7 @@ public unsafe interface IIUnknownStrategy
         /// <param name="iid">The IID (Interface ID) to query for.</param>
         /// <param name="ppObj">The resulting interface.</param>
         /// <returns>Returns an HRESULT represents the success of the operation.</returns>
-        /// <seealso cref="Marshal.QueryInterface(nint, in Guid, out nint)"/>
+        /// <seealso cref="Marshal.QueryInterface(nint, ref readonly Guid, out nint)"/>
         public int QueryInterface(void* instancePtr, in Guid iid, out void* ppObj);
 
         /// <summary>