diff --git a/ICSharpCode.NRefactory/ICSharpCode.NRefactory.csproj b/ICSharpCode.NRefactory/ICSharpCode.NRefactory.csproj
index 8d3905e595..30d194fa34 100644
--- a/ICSharpCode.NRefactory/ICSharpCode.NRefactory.csproj
+++ b/ICSharpCode.NRefactory/ICSharpCode.NRefactory.csproj
@@ -221,6 +221,7 @@
     <Compile Include="TypeSystem\Implementation\ProxyTypeResolveContext.cs" />
     <Compile Include="TypeSystem\Implementation\DefaultTypeDefinition.cs" />
     <Compile Include="TypeSystem\Implementation\SimpleConstantValue.cs" />
+    <Compile Include="TypeSystem\Implementation\SimpleInterningProvider.cs" />
     <Compile Include="TypeSystem\Implementation\SimpleProjectContent.cs" />
     <Compile Include="TypeSystem\Implementation\SpecializedEvent.cs" />
     <Compile Include="TypeSystem\Implementation\SpecializedField.cs" />
diff --git a/ICSharpCode.NRefactory/TypeSystem/CecilLoader.cs b/ICSharpCode.NRefactory/TypeSystem/CecilLoader.cs
index ba64f7f3b7..4b27679d57 100644
--- a/ICSharpCode.NRefactory/TypeSystem/CecilLoader.cs
+++ b/ICSharpCode.NRefactory/TypeSystem/CecilLoader.cs
@@ -38,6 +38,11 @@ namespace ICSharpCode.NRefactory.TypeSystem
 		/// Gets/Sets the documentation provider that is used to retrive the XML documentation for all members.
 		/// </summary>
 		public IDocumentationProvider DocumentationProvider { get; set; }
+		
+		/// <summary>
+		/// Gets/Sets the interning provider.
+		/// </summary>
+		public IInterningProvider InterningProvider { get; set; }
 		#endregion
 		
 		#region Load From AssemblyDefinition
@@ -47,12 +52,16 @@ namespace ICSharpCode.NRefactory.TypeSystem
 				throw new ArgumentNullException("assemblyDefinition");
 			ITypeResolveContext oldEarlyBindContext = this.EarlyBindContext;
 			try {
-				List<IAttribute> assemblyAttributes = new List<IAttribute>();
+				IList<IAttribute> assemblyAttributes = new List<IAttribute>();
 				foreach (var attr in assemblyDefinition.CustomAttributes) {
 					assemblyAttributes.Add(ReadAttribute(attr));
 				}
+				if (this.InterningProvider != null)
+					assemblyAttributes = this.InterningProvider.InternList(assemblyAttributes);
+				else
+					assemblyAttributes = new ReadOnlyCollection<IAttribute>(assemblyAttributes);
 				TypeStorage typeStorage = new TypeStorage();
-				CecilProjectContent pc = new CecilProjectContent(typeStorage, assemblyDefinition.Name.FullName, assemblyAttributes.AsReadOnly(), this.DocumentationProvider);
+				CecilProjectContent pc = new CecilProjectContent(typeStorage, assemblyDefinition.Name.FullName, assemblyAttributes, this.DocumentationProvider);
 				
 				this.EarlyBindContext = CompositeTypeResolveContext.Combine(pc, this.EarlyBindContext);
 				List<CecilTypeDefinition> types = new List<CecilTypeDefinition>();
@@ -105,10 +114,10 @@ namespace ICSharpCode.NRefactory.TypeSystem
 		sealed class CecilProjectContent : ProxyTypeResolveContext, IProjectContent, ISynchronizedTypeResolveContext, IDocumentationProvider
 		{
 			readonly string assemblyName;
-			readonly ReadOnlyCollection<IAttribute> assemblyAttributes;
+			readonly IList<IAttribute> assemblyAttributes;
 			readonly IDocumentationProvider documentationProvider;
 			
-			public CecilProjectContent(TypeStorage types, string assemblyName, ReadOnlyCollection<IAttribute> assemblyAttributes, IDocumentationProvider documentationProvider)
+			public CecilProjectContent(TypeStorage types, string assemblyName, IList<IAttribute> assemblyAttributes, IDocumentationProvider documentationProvider)
 				: base(types)
 			{
 				Debug.Assert(assemblyName != null);
@@ -710,6 +719,8 @@ namespace ICSharpCode.NRefactory.TypeSystem
 				}
 			}
 			
+			if (this.InterningProvider != null)
+				m = this.InterningProvider.Intern(m);
 			return m;
 		}
 		
@@ -830,6 +841,8 @@ namespace ICSharpCode.NRefactory.TypeSystem
 				f.IsVolatile = true;
 			}
 			
+			if (this.InterningProvider != null)
+				f = this.InterningProvider.Intern(f);
 			return f;
 		}
 		
@@ -897,6 +910,8 @@ namespace ICSharpCode.NRefactory.TypeSystem
 			}
 			AddAttributes(property, p);
 			
+			if (this.InterningProvider != null)
+				p = this.InterningProvider.Intern(p);
 			return p;
 		}
 		
@@ -936,6 +951,8 @@ namespace ICSharpCode.NRefactory.TypeSystem
 			
 			AddAttributes(ev, e);
 			
+			if (this.InterningProvider != null)
+				e = this.InterningProvider.Intern(e);
 			return e;
 		}
 		#endregion
diff --git a/ICSharpCode.NRefactory/TypeSystem/Implementation/SimpleInterningProvider.cs b/ICSharpCode.NRefactory/TypeSystem/Implementation/SimpleInterningProvider.cs
new file mode 100644
index 0000000000..66f6aeb172
--- /dev/null
+++ b/ICSharpCode.NRefactory/TypeSystem/Implementation/SimpleInterningProvider.cs
@@ -0,0 +1,122 @@
+// Copyright (c) AlphaSierraPapa for the SharpDevelop Team (for details please see \doc\copyright.txt)
+// This code is distributed under MIT X11 license (for details please see \doc\license.txt)
+
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Linq;
+using System.Runtime.CompilerServices;
+
+using ICSharpCode.NRefactory.Utils;
+
+namespace ICSharpCode.NRefactory.TypeSystem.Implementation
+{
+	/// <summary>
+	/// Simple interning provider.
+	/// </summary>
+	public sealed class SimpleInterningProvider : IInterningProvider
+	{
+		sealed class ReferenceComparer : IEqualityComparer<object>
+		{
+			public readonly static ReferenceComparer Instance = new ReferenceComparer();
+			
+			public new bool Equals(object a, object b)
+			{
+				return ReferenceEquals(a, b);
+			}
+			
+			public int GetHashCode(object obj)
+			{
+				return RuntimeHelpers.GetHashCode(obj);
+			}
+		}
+		
+		sealed class InterningComparer : IEqualityComparer<ISupportsInterning>
+		{
+			public bool Equals(ISupportsInterning x, ISupportsInterning y)
+			{
+				return x.EqualsForInterning(y);
+			}
+			
+			public int GetHashCode(ISupportsInterning obj)
+			{
+				return obj.GetHashCodeForInterning();
+			}
+		}
+		
+		sealed class ListComparer : IEqualityComparer<IEnumerable<object>>
+		{
+			public bool Equals(IEnumerable<object> a, IEnumerable<object> b)
+			{
+				if (a.GetType() != b.GetType())
+					return false;
+				return Enumerable.SequenceEqual(a, b, ReferenceComparer.Instance);
+			}
+			
+			public int GetHashCode(IEnumerable<object> obj)
+			{
+				int hashCode = obj.GetType().GetHashCode();
+				unchecked {
+					foreach (object o in obj) {
+						hashCode *= 27;
+						hashCode += RuntimeHelpers.GetHashCode(o);
+					}
+				}
+				return hashCode;
+			}
+		}
+		
+		Dictionary<object, object> byValueDict = new Dictionary<object, object>();
+		Dictionary<ISupportsInterning, ISupportsInterning> supportsInternDict = new Dictionary<ISupportsInterning, ISupportsInterning>(new InterningComparer());
+		Dictionary<IEnumerable<object>, IEnumerable<object>> listDict = new Dictionary<IEnumerable<object>, IEnumerable<object>>(new ListComparer());
+		
+		public T Intern<T>(T obj) where T : class
+		{
+			if (obj == null)
+				return null;
+			ISupportsInterning s = obj as ISupportsInterning;
+			if (s != null) {
+				ISupportsInterning output;
+				if (supportsInternDict.TryGetValue(s, out output)) {
+					obj = (T)output;
+				} else {
+					s.PrepareForInterning(this);
+					if (supportsInternDict.TryGetValue(s, out output))
+						obj = (T)output;
+					else
+						supportsInternDict.Add(s, s);
+				}
+			} else if (obj is IType || Type.GetTypeCode(obj.GetType()) >= TypeCode.Boolean) {
+				object output;
+				if (byValueDict.TryGetValue(obj, out output))
+					obj = (T)output;
+				else
+					byValueDict.Add(obj, obj);
+			}
+			return obj;
+		}
+		
+		public IList<T> InternList<T>(IList<T> list) where T : class
+		{
+			if (list == null)
+				return null;
+			for (int i = 0; i < list.Count; i++) {
+				T oldItem = list[i];
+				T newItem = Intern(oldItem);
+				if (oldItem != newItem) {
+					if (list.IsReadOnly)
+						list = new T[list.Count];
+					list[i] = newItem;
+				}
+			}
+			if (!list.IsReadOnly)
+				list = new ReadOnlyCollection<T>(list);
+			IEnumerable<object> output;
+			if (listDict.TryGetValue(list, out output))
+				list = (IList<T>)output;
+			else
+				listDict.Add(list, list);
+			return list;
+		}
+	}
+}