/// <summary>
		/// Generates the constructor for the nested class that extends
		/// <see cref="AbstractInvocation"/>
		/// </summary>
		/// <param name="targetFieldType"></param>
		/// <param name="nested"></param>
		/// <param name="targetField"></param>
		/// <param name="version"></param>
		protected void CreateIInvocationConstructor(
			Type targetFieldType, NestedClassEmitter nested, FieldReference targetField, ConstructorVersion version)
		{
			ArgumentReference cArg0 = new ArgumentReference(targetFieldType);
			ArgumentReference cArg1 = new ArgumentReference(typeof(IInterceptor[]));
			ArgumentReference cArg2 = new ArgumentReference(typeof(Type));
			ArgumentReference cArg3 = new ArgumentReference(typeof(MethodInfo));
			ArgumentReference cArg4 = null;
			ArgumentReference cArg6 = new ArgumentReference(typeof(object));

			if (version == ConstructorVersion.WithTargetMethod)
			{
				cArg4 = new ArgumentReference(typeof(MethodInfo));
			}

			ArgumentReference cArg5 = new ArgumentReference(typeof(object[]));

			ConstructorEmitter constructor;

			if (cArg4 == null)
			{
				constructor = nested.CreateConstructor(cArg0, cArg1, cArg2, cArg3, cArg5, cArg6);
			}
			else
			{
				constructor = nested.CreateConstructor(cArg0, cArg1, cArg2, cArg3, cArg4, cArg5, cArg6);
			}

			constructor.CodeBuilder.AddStatement(new AssignStatement(targetField, cArg0.ToExpression()));

			if (cArg4 == null)
			{
				constructor.CodeBuilder.InvokeBaseConstructor(Constants.AbstractInvocationConstructorWithoutTargetMethod,
				                                              cArg0,
				                                              cArg6,
				                                              cArg1,
				                                              cArg2,
				                                              cArg3,
				                                              cArg5);
			}
			else
			{
				constructor.CodeBuilder.InvokeBaseConstructor(Constants.AbstractInvocationConstructorWithTargetMethod,
				                                              cArg0,
				                                              cArg6,
				                                              cArg1,
				                                              cArg2,
				                                              cArg3,
				                                              cArg4,
				                                              cArg5);
			}

			constructor.CodeBuilder.AddStatement(new ReturnStatement());
		}
		/// <summary>
		/// If callbackMethod is null the InvokeOnTarget implementation
		/// is just the code to throw an exception
		/// </summary>
		/// <param name="emitter"></param>
		/// <param name="targetType"></param>
		/// <param name="targetForInvocation"></param>
		/// <param name="methodInfo"></param>
		/// <param name="callbackMethod"></param>
		/// <param name="version"></param>
		/// <param name="allowChangeTarget">If true the invocation will implement the IChangeProxyTarget interface</param>
		/// <returns></returns>
		protected NestedClassEmitter BuildInvocationNestedType(
			ClassEmitter emitter,
			Type targetType,
			Type targetForInvocation,
			MethodInfo methodInfo,
			MethodInfo callbackMethod,
			ConstructorVersion version,
			bool allowChangeTarget)
		{
			CheckNotGenericTypeDefinition(targetType, "targetType");
			CheckNotGenericTypeDefinition(targetForInvocation, "targetForInvocation");

			nestedCounter++;

			Type[] interfaces = new Type[0];

			if (allowChangeTarget)
			{
				interfaces = new Type[] {typeof(IChangeProxyTarget)};
			}

			NestedClassEmitter nested =
				new NestedClassEmitter(emitter,
				                       "Invocation" + methodInfo.Name + "_" + nestedCounter.ToString(),
				                       typeof(AbstractInvocation),
				                       interfaces);

			// invocation only needs to mirror the generic parameters of the MethodInfo
			// targetType cannot be a generic type definition
			nested.CreateGenericParameters(methodInfo.GetGenericArguments());

			// Create the invocation fields

			FieldReference targetRef = nested.CreateField("target", targetForInvocation);

			// Create constructor

			CreateIInvocationConstructor(targetForInvocation, nested, targetRef, version);

			if (allowChangeTarget)
			{
				ArgumentReference argument1 = new ArgumentReference(typeof(object));
				MethodEmitter methodEmitter =
					nested.CreateMethod("ChangeInvocationTarget", MethodAttributes.Public | MethodAttributes.Virtual,
					                    typeof(void), argument1);
				methodEmitter.CodeBuilder.AddStatement(
					new AssignStatement(targetRef,
					                    new ConvertExpression(targetType, argument1.ToExpression())
						)
					);
				methodEmitter.CodeBuilder.AddStatement(new ReturnStatement());
			}

			// InvokeMethodOnTarget implementation

			if (callbackMethod != null)
			{
				ParameterInfo[] parameters = methodInfo.GetParameters();

				CreateIInvocationInvokeOnTarget(emitter, nested, parameters, targetRef, callbackMethod);
			}
			else
			{
				CreateEmptyIInvocationInvokeOnTarget(nested);
			}

			nested.DefineCustomAttribute(new SerializableAttribute());

			return nested;
		}
		/// <summary>
		/// If callbackMethod is null the InvokeOnTarget implementation 
		/// is just the code to throw an exception
		/// </summary>
		/// <param name="emitter"></param>
		/// <param name="targetType"></param>
		/// <param name="targetForInvocation"></param>
		/// <param name="methodInfo"></param>
		/// <param name="callbackMethod"></param>
		/// <param name="version"></param>
		/// <returns></returns>
		protected NestedClassEmitter BuildInvocationNestedType(
			ClassEmitter emitter,
			Type targetType,
			Type targetForInvocation,
			MethodInfo methodInfo,
			MethodInfo callbackMethod,
			ConstructorVersion version)
		{
			CheckNotGenericTypeDefinition(targetType, "targetType");
			CheckNotGenericTypeDefinition(targetForInvocation, "targetForInvocation");
			return
				BuildInvocationNestedType(emitter, targetType, targetForInvocation, methodInfo, callbackMethod, version, false);
		}
		protected MethodEmitter ImplementProxiedMethod(
			Type targetType,
			MethodEmitter methodEmitter,
			MethodInfo method,
			ClassEmitter emitter,
			NestedClassEmitter invocationImpl,
			FieldReference interceptorsField,
			Reference targetRef,
			ConstructorVersion version,
			MethodInfo methodOnTarget)
		{
			CheckNotGenericTypeDefinition(targetType, "targetType");

			methodEmitter.CopyParametersAndReturnTypeFrom(method, emitter);

			TypeReference[] dereferencedArguments = IndirectReference.WrapIfByRef(methodEmitter.Arguments);

			Type iinvocation = invocationImpl.TypeBuilder;

			Trace.Assert(method.IsGenericMethod == iinvocation.IsGenericTypeDefinition);
			bool isGenericInvocationClass = false;
			Type[] genericMethodArgs = new Type[0];
			if (method.IsGenericMethod)
			{
				// bind generic method arguments to invocation's type arguments
				genericMethodArgs = methodEmitter.MethodBuilder.GetGenericArguments();
				iinvocation = iinvocation.MakeGenericType(genericMethodArgs);
				isGenericInvocationClass = true;
			}

			LocalReference invocationImplLocal = methodEmitter.CodeBuilder.DeclareLocal(iinvocation);

			// TODO: Initialize iinvocation instance 
			// with ordinary arguments and in and out arguments

			Expression interceptors;

			// if (useSelector)
			{
				// TODO: Generate code that checks the return of selector
				// if no interceptors is returned, should we invoke the base.Method directly?
			}
			// else
			{
				interceptors = interceptorsField.ToExpression();
			}

			Expression typeTokenFieldExp = typeTokenField.ToExpression();
			Expression methodInfoTokenExp;

			if (method2TokenField.ContainsKey(method)) // Token is in the cache
			{
				methodInfoTokenExp = ((FieldReference) method2TokenField[method]).ToExpression();
			}
			else
			{
				// Not in the cache: generic method

				methodInfoTokenExp = new MethodTokenExpression(method.MakeGenericMethod(genericMethodArgs));
			}

			ConstructorInfo constructor = invocationImpl.Constructors[0].ConstructorBuilder;

			if (isGenericInvocationClass)
			{
				constructor = TypeBuilder.GetConstructor(iinvocation, invocationImpl.Constructors[0].ConstructorBuilder);
			}

			NewInstanceExpression newInvocImpl;

			if (version == ConstructorVersion.WithTargetMethod)
			{
				Expression methodOnTargetTokenExp;

				if (method2TokenField.ContainsKey(methodOnTarget)) // Token is in the cache
				{
					methodOnTargetTokenExp = ((FieldReference) method2TokenField[methodOnTarget]).ToExpression();
				}
				else
				{
					// Not in the cache: generic method

					methodOnTargetTokenExp = new MethodTokenExpression(methodOnTarget.MakeGenericMethod(genericMethodArgs));
				}

				newInvocImpl =
					new NewInstanceExpression(constructor,
					                          targetRef.ToExpression(),
					                          interceptors,
					                          typeTokenFieldExp,
					                          methodOnTargetTokenExp,
					                          methodInfoTokenExp,
					                          new ReferencesToObjectArrayExpression(dereferencedArguments),
					                          SelfReference.Self.ToExpression());
			}
			else
			{
				newInvocImpl =
					new NewInstanceExpression(constructor,
					                          targetRef.ToExpression(),
					                          interceptors,
					                          typeTokenFieldExp,
					                          methodInfoTokenExp,
					                          new ReferencesToObjectArrayExpression(dereferencedArguments),
					                          SelfReference.Self.ToExpression());
			}

			methodEmitter.CodeBuilder.AddStatement(new AssignStatement(invocationImplLocal, newInvocImpl));

			if (method.ContainsGenericParameters)
			{
				EmitLoadGenricMethodArguments(methodEmitter, method.MakeGenericMethod(genericMethodArgs), invocationImplLocal);
			}

			methodEmitter.CodeBuilder.AddStatement(
				new ExpressionStatement(new MethodInvocationExpression(invocationImplLocal, Constants.AbstractInvocationProceed)));

			CopyOutAndRefParameters(dereferencedArguments, invocationImplLocal, method, methodEmitter);

			if (method.ReturnType != typeof(void))
			{
				// Emit code to return with cast from ReturnValue
				MethodInvocationExpression getRetVal =
					new MethodInvocationExpression(invocationImplLocal, typeof(AbstractInvocation).GetMethod("get_ReturnValue"));

				methodEmitter.CodeBuilder.AddStatement(
					new ReturnStatement(new ConvertExpression(methodEmitter.ReturnType, getRetVal)));
			}
			else
			{
				methodEmitter.CodeBuilder.AddStatement(new ReturnStatement());
			}

			return methodEmitter;
		}
		protected MethodEmitter CreateProxiedMethod(
			Type targetType,
			MethodInfo method,
			ClassEmitter emitter,
			NestedClassEmitter invocationImpl,
			FieldReference interceptorsField,
			Reference targetRef,
			ConstructorVersion version,
			MethodInfo methodOnTarget)
		{
			CheckNotGenericTypeDefinition(targetType, "targetType");

			MethodAttributes atts = ObtainMethodAttributes(method);
			MethodEmitter methodEmitter = emitter.CreateMethod(method.Name, atts);

			return
				ImplementProxiedMethod(targetType,
				                       methodEmitter,
				                       method,
				                       emitter,
				                       invocationImpl,
				                       interceptorsField,
				                       targetRef,
				                       version,
				                       methodOnTarget);
		}
		protected MethodEmitter ImplementProxiedMethod(
			Type targetType,
			MethodEmitter methodEmitter,
			MethodInfo method,
			ClassEmitter emitter,
			NestedClassEmitter invocationImpl,
			FieldReference interceptorsField,
			Reference targetRef,
			ConstructorVersion version,
			MethodInfo methodOnTarget)
		{
			CheckNotGenericTypeDefinition(targetType, "targetType");

			methodEmitter.CopyParametersAndReturnTypeFrom(method, emitter);

			TypeReference[] dereferencedArguments = IndirectReference.WrapIfByRef(methodEmitter.Arguments);

			Type iinvocation = invocationImpl.TypeBuilder;

			Trace.Assert(method.IsGenericMethod == iinvocation.IsGenericTypeDefinition);
			bool isGenericInvocationClass = false;
			Type[] genericMethodArgs = new Type[0];
			if (method.IsGenericMethod)
			{
				// bind generic method arguments to invocation's type arguments
				genericMethodArgs = methodEmitter.MethodBuilder.GetGenericArguments();
				iinvocation = iinvocation.MakeGenericType(genericMethodArgs);
				isGenericInvocationClass = true;
			}

			Expression typeTokenFieldExp = typeTokenField.ToExpression();
			Expression methodInfoTokenExp;

			string tokenFieldName;
			if (method2TokenField.ContainsKey(method)) // Token is in the cache
			{
				FieldReference methodTokenField = method2TokenField[method];
				tokenFieldName = methodTokenField.Reference.Name;
				methodInfoTokenExp = methodTokenField.ToExpression();
			}
			else
			{
				// Not in the cache: generic method
				MethodInfo genericMethod = method.MakeGenericMethod(genericMethodArgs);

				// Need random suffix added to the name, so that we don't end up with duplicate field names for
				// methods with the same name, but different generic parameters
				tokenFieldName = string.Format("{0}_{1}_{2}", genericMethod.Name, genericMethodArgs.Length,
				                               Guid.NewGuid().ToString("N"));
				methodInfoTokenExp = new MethodTokenExpression(genericMethod);
			}

			LocalReference invocationImplLocal = methodEmitter.CodeBuilder.DeclareLocal(iinvocation);

			// TODO: Initialize iinvocation instance with ordinary arguments and in and out arguments

			Expression interceptors = interceptorsField.ToExpression();

			// Create the field to store the selected interceptors for this method if an InterceptorSelector is specified
			FieldReference methodInterceptors = null;
			if (proxyGenerationOptions.Selector != null)
			{
				// If no interceptors are returned, should we invoke the base.Method directly? Looks like we should not.
				methodInterceptors = emitter.CreateField(string.Format("{0}_interceptors", tokenFieldName), typeof(IInterceptor[]));
			}

			ConstructorInfo constructor = invocationImpl.Constructors[0].ConstructorBuilder;
			if (isGenericInvocationClass)
			{
				constructor = TypeBuilder.GetConstructor(iinvocation, constructor);
			}

			NewInstanceExpression newInvocImpl;

			if (version == ConstructorVersion.WithTargetMethod)
			{
				Expression methodOnTargetTokenExp;

				if (method2TokenField.ContainsKey(methodOnTarget)) // Token is in the cache
				{
					methodOnTargetTokenExp = method2TokenField[methodOnTarget].ToExpression();
				}
				else
				{
					// Not in the cache: generic method

					methodOnTargetTokenExp = new MethodTokenExpression(methodOnTarget.MakeGenericMethod(genericMethodArgs));
				}
				if (methodInterceptors == null)
				{
					newInvocImpl = //actual contructor call
						new NewInstanceExpression(constructor,
						                          targetRef.ToExpression(),
						                          interceptors,
						                          typeTokenFieldExp,
						                          methodOnTargetTokenExp,
						                          methodInfoTokenExp,
						                          new ReferencesToObjectArrayExpression(dereferencedArguments),
						                          SelfReference.Self.ToExpression());
				}
				else
				{
					MethodInvocationExpression methodInvocationExpression =
						new MethodInvocationExpression(proxyGenerationOptionsField, proxyGenerationOptions_Selector);
					methodInvocationExpression.VirtualCall = true;

					newInvocImpl = //actual contructor call
						new NewInstanceExpression(constructor,
						                          targetRef.ToExpression(),
						                          interceptors,
						                          typeTokenFieldExp,
						                          methodOnTargetTokenExp,
						                          methodInfoTokenExp,
						                          new ReferencesToObjectArrayExpression(dereferencedArguments),
						                          SelfReference.Self.ToExpression(),
						                          methodInvocationExpression,
						                          new AddressOfReferenceExpression(methodInterceptors));
				}
			}
			else
			{
				if (methodInterceptors == null)
				{
					newInvocImpl =
						new NewInstanceExpression(constructor,
						                          targetRef.ToExpression(),
						                          interceptors,
						                          typeTokenFieldExp,
						                          methodInfoTokenExp,
						                          new ReferencesToObjectArrayExpression(dereferencedArguments),
						                          SelfReference.Self.ToExpression());
				}
				else
				{
					MethodInvocationExpression methodInvocationExpression =
						new MethodInvocationExpression(proxyGenerationOptionsField, proxyGenerationOptions_Selector);
					methodInvocationExpression.VirtualCall = true;

					newInvocImpl =
						new NewInstanceExpression(constructor,
						                          targetRef.ToExpression(),
						                          interceptors,
						                          typeTokenFieldExp,
						                          methodInfoTokenExp,
						                          new ReferencesToObjectArrayExpression(dereferencedArguments),
						                          SelfReference.Self.ToExpression(),
						                          methodInvocationExpression,
						                          new AddressOfReferenceExpression(methodInterceptors));
				}
			}

			methodEmitter.CodeBuilder.AddStatement(new AssignStatement(invocationImplLocal, newInvocImpl));

			if (method.ContainsGenericParameters)
			{
				EmitLoadGenricMethodArguments(methodEmitter, method.MakeGenericMethod(genericMethodArgs), invocationImplLocal);
			}

			methodEmitter.CodeBuilder.AddStatement(
				new ExpressionStatement(new MethodInvocationExpression(invocationImplLocal, Constants.AbstractInvocationProceed)));

			CopyOutAndRefParameters(dereferencedArguments, invocationImplLocal, method, methodEmitter);

			if (method.ReturnType != typeof(void))
			{
				// Emit code to return with cast from ReturnValue
				MethodInvocationExpression getRetVal =
					new MethodInvocationExpression(invocationImplLocal, typeof(AbstractInvocation).GetMethod("get_ReturnValue"));

				methodEmitter.CodeBuilder.AddStatement(
					new ReturnStatement(new ConvertExpression(methodEmitter.ReturnType, getRetVal)));
			}
			else
			{
				methodEmitter.CodeBuilder.AddStatement(new ReturnStatement());
			}

			return methodEmitter;
		}