Expose IsReferenceOrContainsReferences in System.Runtime contract (#1…

…6414)

Fixes #14047

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

@@ -6400,7 +6400,8 @@ public static void PrepareMethod(System.RuntimeMethodHandle method, System.Runti
         public static void ProbeForSufficientStack() { }
         public static bool TryEnsureSufficientExecutionStack() { throw null; }
         public static object GetUninitializedObject(Type type) { throw null; }
-   }
+        public static bool IsReferenceOrContainsReferences<T>() { throw null; }
+    }
     [System.AttributeUsageAttribute((System.AttributeTargets)(64), Inherited = false, AllowMultiple = false)]
     public partial class StateMachineAttribute : System.Attribute
     {

src/System.Runtime/tests/System/Runtime/CompilerServices/RuntimeHelpersTests.netcoreapp.cs

@@ -2,6 +2,8 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+using System.Runtime.InteropServices;
+
 using Xunit;
 
 namespace System.Runtime.CompilerServices.Tests
@@ -66,5 +68,28 @@ private class ObjectWithDefaultCtor
         {
             public int Value = 42;
         }
+
+        [Fact]
+        public static void IsReferenceOrContainsReferences()
+        {
+            Assert.False(RuntimeHelpers.IsReferenceOrContainsReferences<int>());
+            Assert.True(RuntimeHelpers.IsReferenceOrContainsReferences<string>());
+            Assert.False(RuntimeHelpers.IsReferenceOrContainsReferences<Guid>());
+            Assert.False(RuntimeHelpers.IsReferenceOrContainsReferences<StructWithoutReferences>());
+            Assert.True(RuntimeHelpers.IsReferenceOrContainsReferences<StructWithReferences>());
+        }
+
+        [StructLayoutAttribute(LayoutKind.Sequential)]
+        private struct StructWithoutReferences
+        {
+            public int a, b, c;
+        }
+
+        [StructLayoutAttribute(LayoutKind.Sequential)]
+        private struct StructWithReferences
+        {
+            public int a, b, c;
+            public object d;
+        }
     }
 }