1 files changed, 20 insertions, 0 deletions

diff --git a/csharp/src/Google.Protobuf/Reflection/ReflectionUtil.cs b/csharp/src/Google.Protobuf/Reflection/ReflectionUtil.cs
index d0dc3e8b..ec222dc1 100644
--- a/csharp/src/Google.Protobuf/Reflection/ReflectionUtil.cs
+++ b/csharp/src/Google.Protobuf/Reflection/ReflectionUtil.cs
@@ -31,6 +31,7 @@
 #endregion
 
 using System;
+using System.Collections.Generic;
 using System.Linq.Expressions;
 using System.Reflection;
 
@@ -102,5 +103,24 @@ namespace Google.Protobuf.Reflection
             Expression call = Expression.Call(castTarget, method);
             return Expression.Lambda<Action<object>>(call, targetParameter).Compile();
         }
+
+        /// <summary>
+        /// Returns the next type from an iterator of types, unless the iterator is a null reference,
+        /// in which case null is returned.
+        /// </summary>
+        internal static Type GetNextType(IEnumerator<Type> generatedTypeIterator)
+        {
+            if (generatedTypeIterator == null)
+            {
+                return null;
+            }
+            if (!generatedTypeIterator.MoveNext())
+            {
+                // This parameter name corresponds to any public method supplying the generated types to start with.
+                throw new ArgumentException("More generated types left over after consuming all expected ones", "generatedTypes");
+            }
+            return generatedTypeIterator.Current;
+        }
+
     }
 }
\ No newline at end of file