diff --git a/ICSharpCode.NRefactory/TypeSystem/IMethod.cs b/ICSharpCode.NRefactory/TypeSystem/IMethod.cs
index c534c0d815..ddf5c97513 100644
--- a/ICSharpCode.NRefactory/TypeSystem/IMethod.cs
+++ b/ICSharpCode.NRefactory/TypeSystem/IMethod.cs
@@ -88,20 +88,27 @@ namespace ICSharpCode.NRefactory.TypeSystem
 		/// Gets the unresolved method parts.
 		/// For partial methods, this returns all parts.
 		/// Otherwise, this returns an array with a single element (new[] { UnresolvedMember }).
+		/// NOTE: The type will change to IReadOnlyList<IUnresolvedMethod> in future versions.
 		/// </summary>
 		IList<IUnresolvedMethod> Parts { get; }
 		
 		/// <summary>
 		/// Gets the attributes associated with the return type. (e.g. [return: MarshalAs(...)])
+		/// NOTE: The type will change to IReadOnlyList<IAttribute> in future versions.
 		/// </summary>
 		IList<IAttribute> ReturnTypeAttributes { get; }
-		
+
+
+		/// <summary>
+		/// NOTE: The type will change to IReadOnlyList<ITypeParameter> in future versions.
+		/// </summary>
 		IList<ITypeParameter> TypeParameters { get; }
 
 		/// <summary>
 		/// Gets the type arguments passed to this method.
 		/// If only the type parameters for the class were specified and the generic method
 		/// itself is not specialized yet, this property will return an empty list.
+		/// NOTE: The type will change to IReadOnlyList<IType> in future versions.
 		/// </summary>
 		IList<IType> TypeArguments {
 			get;
diff --git a/ICSharpCode.NRefactory/TypeSystem/IType.cs b/ICSharpCode.NRefactory/TypeSystem/IType.cs
index 2d010e22b9..d611d0c065 100644
--- a/ICSharpCode.NRefactory/TypeSystem/IType.cs
+++ b/ICSharpCode.NRefactory/TypeSystem/IType.cs
@@ -18,6 +18,7 @@
 
 using System;
 using System.Collections.Generic;
+using ICSharpCode.NRefactory.TypeSystem.Implementation;
 
 namespace ICSharpCode.NRefactory.TypeSystem
 {
@@ -80,7 +81,15 @@ namespace ICSharpCode.NRefactory.TypeSystem
 		/// Gets the number of type parameters.
 		/// </summary>
 		int TypeParameterCount { get; }
-		
+
+		/// <summary>
+		/// Gets the type arguments passed to this type.
+		/// If only the type parameters for the class were specified and the generic type
+		/// itself is not specialized yet or the TypeParameterCount is 0, this property will return an empty list.
+		/// NOTE: The type will change to IReadOnlyList<IType> in future versions.
+		/// </summary>
+		IList<IType> TypeArguments { get; }
+
 		/// <summary>
 		/// Calls ITypeVisitor.Visit for this type.
 		/// </summary>
@@ -110,6 +119,22 @@ namespace ICSharpCode.NRefactory.TypeSystem
 		/// Otherwise, the main resolve context of a compilation is sufficient.
 		/// </remarks>
 		ITypeReference ToTypeReference();
+
+		/// <summary>
+		/// Gets a type visitor that performs the substitution of class type parameters with the type arguments
+		/// of this parameterized type.
+		/// Returns TypeParameterSubstitution.Identity if the type is not parametrized.
+		/// </summary>
+		TypeParameterSubstitution GetSubstitution();
+		
+		/// <summary>
+		/// Gets a type visitor that performs the substitution of class type parameters with the type arguments
+		/// of this parameterized type,
+		/// and also substitutes method type parameters with the specified method type arguments.
+		/// Returns TypeParameterSubstitution.Identity if the type is not parametrized.
+		/// </summary>
+		TypeParameterSubstitution GetSubstitution(IList<IType> methodTypeArguments);
+
 		
 		/// <summary>
 		/// Gets inner classes (including inherited inner classes).
diff --git a/ICSharpCode.NRefactory/TypeSystem/Implementation/AbstractResolvedTypeParameter.cs b/ICSharpCode.NRefactory/TypeSystem/Implementation/AbstractResolvedTypeParameter.cs
index cede6c7a8b..6afa854d0c 100644
--- a/ICSharpCode.NRefactory/TypeSystem/Implementation/AbstractResolvedTypeParameter.cs
+++ b/ICSharpCode.NRefactory/TypeSystem/Implementation/AbstractResolvedTypeParameter.cs
@@ -206,7 +206,12 @@ namespace ICSharpCode.NRefactory.TypeSystem.Implementation
 		int IType.TypeParameterCount {
 			get { return 0; }
 		}
-		
+
+		readonly static IList<IType> emptyTypeArguments = new IType[0];
+		IList<IType> IType.TypeArguments {
+			get { return emptyTypeArguments; }
+		}
+
 		public abstract IEnumerable<IType> DirectBaseTypes { get; }
 		
 		public string Name {
@@ -326,7 +331,17 @@ namespace ICSharpCode.NRefactory.TypeSystem.Implementation
 			else
 				return GetMembersHelper.GetAccessors(this, FilterNonStatic(filter), options);
 		}
+
+		public TypeParameterSubstitution GetSubstitution()
+		{
+			return TypeParameterSubstitution.Identity;
+		}
 		
+		public TypeParameterSubstitution GetSubstitution(IList<IType> methodTypeArguments)
+		{
+			return TypeParameterSubstitution.Identity;
+		}
+
 		static Predicate<T> FilterNonStatic<T>(Predicate<T> filter) where T : class, IUnresolvedMember
 		{
 			if (filter == null)
diff --git a/ICSharpCode.NRefactory/TypeSystem/Implementation/AbstractType.cs b/ICSharpCode.NRefactory/TypeSystem/Implementation/AbstractType.cs
index 48aac56559..3d68ee62d0 100644
--- a/ICSharpCode.NRefactory/TypeSystem/Implementation/AbstractType.cs
+++ b/ICSharpCode.NRefactory/TypeSystem/Implementation/AbstractType.cs
@@ -58,7 +58,12 @@ namespace ICSharpCode.NRefactory.TypeSystem.Implementation
 		public virtual int TypeParameterCount {
 			get { return 0; }
 		}
-		
+
+		readonly static IList<IType> emptyTypeArguments = new IType[0];
+		IList<IType> IType.TypeArguments {
+			get { return emptyTypeArguments; }
+		}
+
 		public virtual IType DeclaringType {
 			get { return null; }
 		}
@@ -128,6 +133,16 @@ namespace ICSharpCode.NRefactory.TypeSystem.Implementation
 			return EmptyList<IMethod>.Instance;
 		}
 		
+		public TypeParameterSubstitution GetSubstitution()
+		{
+			return TypeParameterSubstitution.Identity;
+		}
+		
+		public TypeParameterSubstitution GetSubstitution(IList<IType> methodTypeArguments)
+		{
+			return TypeParameterSubstitution.Identity;
+		}
+
 		public override sealed bool Equals(object obj)
 		{
 			return Equals(obj as IType);
diff --git a/ICSharpCode.NRefactory/TypeSystem/Implementation/DefaultResolvedTypeDefinition.cs b/ICSharpCode.NRefactory/TypeSystem/Implementation/DefaultResolvedTypeDefinition.cs
index b6cd1e09ce..cee886cb57 100644
--- a/ICSharpCode.NRefactory/TypeSystem/Implementation/DefaultResolvedTypeDefinition.cs
+++ b/ICSharpCode.NRefactory/TypeSystem/Implementation/DefaultResolvedTypeDefinition.cs
@@ -492,7 +492,12 @@ namespace ICSharpCode.NRefactory.TypeSystem.Implementation
 		public int TypeParameterCount {
 			get { return parts[0].TypeParameters.Count; }
 		}
-		
+
+		readonly static IList<IType> emptyTypeArguments = new IType[0];
+		IList<IType> IType.TypeArguments {
+			get { return emptyTypeArguments; }
+		}
+
 		#region DirectBaseTypes
 		IList<IType> directBaseTypes;
 		
@@ -904,6 +909,16 @@ namespace ICSharpCode.NRefactory.TypeSystem.Implementation
 		}
 		#endregion
 		
+		public TypeParameterSubstitution GetSubstitution()
+		{
+			return TypeParameterSubstitution.Identity;
+		}
+		
+		public TypeParameterSubstitution GetSubstitution(IList<IType> methodTypeArguments)
+		{
+			return TypeParameterSubstitution.Identity;
+		}
+
 		public bool Equals(IType other)
 		{
 			return this == other;
diff --git a/ICSharpCode.NRefactory/TypeSystem/ParameterizedType.cs b/ICSharpCode.NRefactory/TypeSystem/ParameterizedType.cs
index dbe0b86f15..658f715e0c 100644
--- a/ICSharpCode.NRefactory/TypeSystem/ParameterizedType.cs
+++ b/ICSharpCode.NRefactory/TypeSystem/ParameterizedType.cs
@@ -137,12 +137,12 @@ namespace ICSharpCode.NRefactory.TypeSystem
 			return ReflectionName;
 		}
 		
-		public ReadOnlyCollection<IType> TypeArguments {
+		public IList<IType> TypeArguments {
 			get {
-				return Array.AsReadOnly(typeArguments);
+				return typeArguments;
 			}
 		}
-		
+
 		/// <summary>
 		/// Same as 'parameterizedType.TypeArguments[index]', but is a bit more efficient (doesn't require the read-only wrapper).
 		/// </summary>