//-----------------------------------------------------------------------------
// Copyright (c) Microsoft Corporation.  All rights reserved.
//-----------------------------------------------------------------------------

namespace System.Activities
{
    using System;
    using System.Collections.ObjectModel;
    using System.ComponentModel;
    using System.Linq;
    using System.Linq.Expressions;
    using System.Reflection;
    using System.Runtime;
    using System.Runtime.Serialization;
    using System.Collections.Generic;
    using System.Diagnostics.CodeAnalysis;
    using System.Activities.XamlIntegration;

    static class ExpressionUtilities
    {
        public static ParameterExpression RuntimeContextParameter = Expression.Parameter(typeof(ActivityContext), "context");
        static Assembly linqAssembly = typeof(Func<>).Assembly;
        static MethodInfo createLocationFactoryGenericMethod = typeof(ExpressionUtilities).GetMethod("CreateLocationFactory");
        static MethodInfo propertyDescriptorGetValue; // PropertyDescriptor.GetValue


        // Types cached for use in TryRewriteLambdaExpression
        static Type inArgumentGenericType = typeof(InArgument<>);
        static Type outArgumentGenericType = typeof(OutArgument<>);
        static Type inOutArgumentGenericType = typeof(InOutArgument<>);
        static Type variableGenericType = typeof(Variable<>);
        static Type delegateInArgumentGenericType = typeof(DelegateInArgument<>);
        static Type delegateOutArgumentGenericType = typeof(DelegateOutArgument<>);
        static Type activityContextType = typeof(ActivityContext);
        static Type locationReferenceType = typeof(LocationReference);
        static Type runtimeArgumentType = typeof(RuntimeArgument);
        static Type argumentType = typeof(Argument);
        static Type variableType = typeof(Variable);
        static Type delegateArgumentType = typeof(DelegateArgument);

        // MethodInfos cached for use in TryRewriteLambdaExpression
        static MethodInfo activityContextGetValueGenericMethod = typeof(ActivityContext).GetMethod("GetValue", new Type[] { typeof(LocationReference) });
        static MethodInfo activityContextGetLocationGenericMethod = typeof(ActivityContext).GetMethod("GetLocation", new Type[] { typeof(LocationReference) });
        static MethodInfo locationReferenceGetLocationMethod = typeof(LocationReference).GetMethod("GetLocation", new Type[] { typeof(ActivityContext) });
        static MethodInfo argumentGetLocationMethod = typeof(Argument).GetMethod("GetLocation", new Type[] { typeof(ActivityContext) });
        static MethodInfo variableGetMethod = typeof(Variable).GetMethod("Get", new Type[] { typeof(ActivityContext) });
        static MethodInfo delegateArgumentGetMethod = typeof(DelegateArgument).GetMethod("Get", new Type[] { typeof(ActivityContext) });

        static MethodInfo PropertyDescriptorGetValue
        {
            get
            {
                if (propertyDescriptorGetValue == null)
                {
                    propertyDescriptorGetValue = typeof(PropertyDescriptor).GetMethod("GetValue");
                }

                return propertyDescriptorGetValue;
            }
        }

        public static Expression CreateIdentifierExpression(LocationReference locationReference)
        {
            return Expression.Call(RuntimeContextParameter, activityContextGetValueGenericMethod.MakeGenericMethod(locationReference.Type), Expression.Constant(locationReference, typeof(LocationReference)));
        }

        // If we ever expand the depth to which we'll look through an expression for a location,
        // then we also need to update the depth to which isLocationExpression is propagated in
        // ExpressionUtilities.TryRewriteLambdaExpression and VisualBasicHelper.Rewrite.
        public static bool IsLocation(LambdaExpression expression, Type targetType, out string extraErrorMessage)
        {
            extraErrorMessage = null;
            Expression body = expression.Body;

            if (targetType != null && body.Type != targetType)
            {
                // eg) LambdaReference<IComparable>((env) => strVar.Get(env))
                // you can have an expressionTree whose LambdaExpression.ReturnType == IComparable,
                // while its LambdaExpression.Body.Type == String
                // and not ever have Convert node in the tree.
                extraErrorMessage = SR.MustMatchReferenceExpressionReturnType;
                return false;
            }

            switch (body.NodeType)
            {
                case ExpressionType.ArrayIndex:
                    return true;

                case ExpressionType.MemberAccess:
                    // This also handles variables, which are emitted as "context.GetLocation<T>("v").Value"
                    MemberExpression memberExpression = (MemberExpression)body;
                    MemberTypes memberType = memberExpression.Member.MemberType;
                    if (memberType == MemberTypes.Field)
                    {
                        FieldInfo fieldInfo = (FieldInfo)memberExpression.Member;
                        if (fieldInfo.IsInitOnly)
                        {
                            // readOnly field
                            return false;
                        }
                        return true;
                    }
                    else if (memberType == MemberTypes.Property)
                    {
                        PropertyInfo propertyInfo = (PropertyInfo)memberExpression.Member;
                        if (!propertyInfo.CanWrite)
                        {
                            // no Setter
                            return false;
                        }
                        return true;
                    }
                    break;

                case ExpressionType.Call:
                    // Depends on the method being called.
                    //     System.Array.Get --> multi-dimensional array
                    //     get_Item --> might be an indexer property if it's special name & default etc.

                    MethodCallExpression callExpression = (MethodCallExpression)body;
                    MethodInfo method = callExpression.Method;

                    Type declaringType = method.DeclaringType;
                    if (declaringType.BaseType == TypeHelper.ArrayType && method.Name == "Get")
                    {
                        return true;
                    }
                    else if (method.IsSpecialName && method.Name.StartsWith("get_", StringComparison.Ordinal))
                    {
                        return true;
                    }
                    else if (method.Name == "GetValue" && declaringType == activityContextType)
                    {
                        return true;
                    }
                    else if (method.Name == "Get" && declaringType.IsGenericType)
                    {
                        Type declaringTypeGenericDefinition = declaringType.GetGenericTypeDefinition();

                        if (declaringTypeGenericDefinition == inOutArgumentGenericType ||
                            declaringTypeGenericDefinition == outArgumentGenericType)
                        {
                            return true;
                        }
                    }
                    break;

                case ExpressionType.Convert:
                    // a would-be-valid Location expression that is type converted is treated invalid
                    extraErrorMessage = SR.MustMatchReferenceExpressionReturnType;
                    return false;
            }
            return false;
        }

        public static LocationFactory<T> CreateLocationFactory<T>(LambdaExpression expression)
        {
            Expression body = expression.Body;

            switch (body.NodeType)
            {
                case ExpressionType.ArrayIndex:
                    return new ArrayLocationFactory<T>(expression);

                case ExpressionType.MemberAccess:
                    // This also handles variables, which are emitted as "context.GetLocation<T>("v").Value"
                    MemberTypes memberType = ((MemberExpression)body).Member.MemberType;
                    if (memberType == MemberTypes.Field)
                    {
                        return new FieldLocationFactory<T>(expression);
                    }
                    else if (memberType == MemberTypes.Property)
                    {
                        return new PropertyLocationFactory<T>(expression);
                    }
                    else
                    {
                        throw FxTrace.Exception.AsError(new NotSupportedException("Lvalues of member type " + memberType));
                    }

                case ExpressionType.Call:
                    // Depends on the method being called.
                    //     System.Array.Get --> multi-dimensional array
                    //     get_Item --> might be an indexer property if it's special name & default etc.

                    MethodCallExpression callExpression = (MethodCallExpression)body;
                    MethodInfo method = callExpression.Method;

                    Type declaringType = method.DeclaringType;
                    if (declaringType.BaseType == TypeHelper.ArrayType && method.Name == "Get")
                    {
                        return new MultidimensionalArrayLocationFactory<T>(expression);
                    }
                    else if (method.IsSpecialName && method.Name.StartsWith("get_", StringComparison.Ordinal))
                    {
                        return new IndexerLocationFactory<T>(expression);
                    }
                    else if (method.Name == "GetValue" && declaringType == activityContextType)
                    {
                        return new LocationReferenceFactory<T>(callExpression.Arguments[0], expression.Parameters);
                    }
                    else if (method.Name == "Get" && declaringType.IsGenericType)
                    {
                        Type declaringTypeGenericDefinition = declaringType.GetGenericTypeDefinition();

                        if (declaringTypeGenericDefinition == inOutArgumentGenericType ||
                            declaringTypeGenericDefinition == outArgumentGenericType)
                        {
                            return new ArgumentFactory<T>(callExpression.Object, expression.Parameters);
                        }
                    }

                    throw FxTrace.Exception.AsError(new InvalidOperationException(SR.InvalidExpressionForLocation(body.NodeType)));

                default:
                    throw FxTrace.Exception.AsError(new InvalidOperationException(SR.InvalidExpressionForLocation(body.NodeType)));
            }
        }

        internal static bool TryGetInlinedReference(CodeActivityPublicEnvironmentAccessor publicAccessor, LocationReference originalReference,
            bool isLocationExpression, out LocationReference inlinedReference)
        {
            if (isLocationExpression)
            {
                return publicAccessor.TryGetReferenceToPublicLocation(originalReference, true, out inlinedReference);
            }
            else
            {
                return publicAccessor.TryGetAccessToPublicLocation(originalReference, ArgumentDirection.In, true, out inlinedReference);
            }
        }

        static LocationFactory CreateParentReference(Expression expression, ReadOnlyCollection<ParameterExpression> lambdaParameters)
        {
            // create a LambdaExpression to get access to the expression
            int parameterCount = lambdaParameters.Count;
            Type genericFuncType = linqAssembly.GetType("System.Func`" + (parameterCount + 1), true);
            Type[] delegateParameterTypes = new Type[parameterCount + 1];

            for (int i = 0; i < parameterCount; ++i)
            {
                delegateParameterTypes[i] = lambdaParameters[i].Type;
            }
            delegateParameterTypes[parameterCount] = expression.Type;
            Type funcType = genericFuncType.MakeGenericType(delegateParameterTypes);
            LambdaExpression parentLambda = Expression.Lambda(funcType, expression, lambdaParameters);

            // call CreateLocationFactory<parentLambda.Type>(parentLambda);
            MethodInfo typedMethod = createLocationFactoryGenericMethod.MakeGenericMethod(expression.Type);
            return (LocationFactory)typedMethod.Invoke(null, new object[] { parentLambda });
        }

        static Func<ActivityContext, T> Compile<T>(Expression objectExpression, ReadOnlyCollection<ParameterExpression> parametersCollection)
        {
            ParameterExpression[] parameters = null;
            if (parametersCollection != null)
            {
                parameters = parametersCollection.ToArray<ParameterExpression>();
            }

            Expression<Func<ActivityContext, T>> objectLambda = Expression.Lambda<Func<ActivityContext, T>>(objectExpression, parameters);
            return objectLambda.Compile();
        }

        static T Evaluate<T>(Expression objectExpression, ReadOnlyCollection<ParameterExpression> parametersCollection, ActivityContext context)
        {
            Func<ActivityContext, T> objectFunc = Compile<T>(objectExpression, parametersCollection);
            return objectFunc(context);
        }

        // for single-dimensional arrays 
        class ArrayLocationFactory<T> : LocationFactory<T>
        {
            Func<ActivityContext, T[]> arrayFunction;
            Func<ActivityContext, int> indexFunction;

            public ArrayLocationFactory(LambdaExpression expression)
            {
                Fx.Assert(expression.Body.NodeType == ExpressionType.ArrayIndex, "ArrayIndex expression required");
                BinaryExpression arrayIndexExpression = (BinaryExpression)expression.Body;

                this.arrayFunction = ExpressionUtilities.Compile<T[]>(arrayIndexExpression.Left, expression.Parameters);
                this.indexFunction = ExpressionUtilities.Compile<int>(arrayIndexExpression.Right, expression.Parameters);
            }

            public override Location<T> CreateLocation(ActivityContext context)
            {
                return new ArrayLocation(this.arrayFunction(context), this.indexFunction(context));
            }

            [DataContract]
            internal class ArrayLocation : Location<T>
            {
                T[] array;

                int index;

                public ArrayLocation(T[] array, int index)
                    : base()
                {
                    this.array = array;
                    this.index = index;
                }

                public override T Value
                {
                    get
                    {
                        return this.array[this.index];
                    }
                    set
                    {
                        this.array[this.index] = value;
                    }
                }

                [DataMember(Name = "array")]
                internal T[] SerializedArray
                {
                    get { return this.array; }
                    set { this.array = value; }
                }

                [DataMember(EmitDefaultValue = false, Name = "index")]
                internal int SerializedIndex
                {
                    get { return this.index; }
                    set { this.index = value; }
                }
            }
        }

        class FieldLocationFactory<T> : LocationFactory<T>
        {
            FieldInfo fieldInfo;
            Func<ActivityContext, object> ownerFunction;
            LocationFactory parentFactory;

            public FieldLocationFactory(LambdaExpression expression)
            {
                Fx.Assert(expression.Body.NodeType == ExpressionType.MemberAccess, "field expression required");
                MemberExpression memberExpression = (MemberExpression)expression.Body;

                Fx.Assert(memberExpression.Member.MemberType == MemberTypes.Field, "member field expected");
                this.fieldInfo = (FieldInfo)memberExpression.Member;

                if (this.fieldInfo.IsStatic)
                {
                    this.ownerFunction = null;
                }
                else
                {
                    this.ownerFunction = ExpressionUtilities.Compile<object>(
                    Expression.Convert(memberExpression.Expression, TypeHelper.ObjectType), expression.Parameters);
                }

                if (this.fieldInfo.DeclaringType.IsValueType)
                {
                    // may want to set a struct, so we need to make an expression in order to set the parent
                    parentFactory = CreateParentReference(memberExpression.Expression, expression.Parameters);
                }
            }

            public override Location<T> CreateLocation(ActivityContext context)
            {
                object owner = null;
                if (this.ownerFunction != null)
                {
                    owner = this.ownerFunction(context);
                }

                Location parent = null;
                if (parentFactory != null)
                {
                    parent = parentFactory.CreateLocation(context);
                }
                return new FieldLocation(this.fieldInfo, owner, parent);
            }

            [DataContract]
            internal class FieldLocation : Location<T>
            {
                FieldInfo fieldInfo;

                object owner;

                Location parent;

                public FieldLocation(FieldInfo fieldInfo, object owner, Location parent)
                    : base()
                {
                    this.fieldInfo = fieldInfo;
                    this.owner = owner;
                    this.parent = parent;
                }

                [SuppressMessage(FxCop.Category.Usage, FxCop.Rule.DoNotRaiseReservedExceptionTypes,
                    Justification = "Need to raise NullReferenceException to match expected failure case in workflows.")]
                public override T Value
                {
                    get
                    {
                        if (this.owner == null && !this.fieldInfo.IsStatic)
                        {
                            throw FxTrace.Exception.AsError(new NullReferenceException(SR.CannotDereferenceNull(this.fieldInfo.Name)));
                        }

                        return (T)this.fieldInfo.GetValue(this.owner);
                    }
                    set
                    {
                        if (this.owner == null && !this.fieldInfo.IsStatic)
                        {
                            throw FxTrace.Exception.AsError(new NullReferenceException(SR.CannotDereferenceNull(this.fieldInfo.Name)));
                        }

                        this.fieldInfo.SetValue(this.owner, value);
                        if (this.parent != null)
                        {
                            // Looks like we are trying to set a field on a struct
                            // Calling SetValue simply sets the field on the local copy of the struct, which is not very helpful
                            // Since we have a copy, assign it back to the parent
                            this.parent.Value = this.owner;
                        }
                    }
                }

                [DataMember(Name = "fieldInfo")]
                internal FieldInfo SerializedFieldInfo
                {
                    get { return this.fieldInfo; }
                    set { this.fieldInfo = value; }
                }

                [DataMember(EmitDefaultValue = false, Name = "owner")]
                internal object SerializedOwner
                {
                    get { return this.owner; }
                    set { this.owner = value; }
                }

                [DataMember(EmitDefaultValue = false, Name = "parent")]
                internal Location SerializedParent
                {
                    get { return this.parent; }
                    set { this.parent = value; }
                }
            }
        }

        class ArgumentFactory<T> : LocationFactory<T>
        {
            Func<ActivityContext, Argument> argumentFunction;

            public ArgumentFactory(Expression argumentExpression, ReadOnlyCollection<ParameterExpression> expressionParameters)
            {
                this.argumentFunction = ExpressionUtilities.Compile<Argument>(argumentExpression, expressionParameters);
            }

            public override Location<T> CreateLocation(ActivityContext context)
            {
                Argument argument = this.argumentFunction(context);

                return argument.RuntimeArgument.GetLocation(context) as Location<T>;
            }
        }

        class LocationReferenceFactory<T> : LocationFactory<T>
        {
            Func<ActivityContext, LocationReference> locationReferenceFunction;

            public LocationReferenceFactory(Expression locationReferenceExpression, ReadOnlyCollection<ParameterExpression> expressionParameters)
            {
                this.locationReferenceFunction = ExpressionUtilities.Compile<LocationReference>(locationReferenceExpression, expressionParameters);
            }

            public override Location<T> CreateLocation(ActivityContext context)
            {
                LocationReference locationReference = this.locationReferenceFunction(context);
                return locationReference.GetLocation(context) as Location<T>;
            }
        }

        class IndexerLocationFactory<T> : LocationFactory<T>
        {
            MethodInfo getItemMethod;
            string indexerName;
            MethodInfo setItemMethod;
            Func<ActivityContext, object>[] setItemArgumentFunctions;
            Func<ActivityContext, object> targetObjectFunction;

            public IndexerLocationFactory(LambdaExpression expression)
            {
                Fx.Assert(expression.Body.NodeType == ExpressionType.Call, "Call expression required.");

                MethodCallExpression callExpression = (MethodCallExpression)expression.Body;
                this.getItemMethod = callExpression.Method;

                Fx.Assert(this.getItemMethod.IsSpecialName && this.getItemMethod.Name.StartsWith("get_", StringComparison.Ordinal), "Special get_Item method required.");

                //  Get the set_Item accessor for the same set of parameter/return types if any.
                this.indexerName = this.getItemMethod.Name.Substring(4);
                string setItemName = "set_" + this.indexerName;
                ParameterInfo[] getItemParameters = this.getItemMethod.GetParameters();
                Type[] setItemParameterTypes = new Type[getItemParameters.Length + 1];

                for (int i = 0; i < getItemParameters.Length; i++)
                {
                    setItemParameterTypes[i] = getItemParameters[i].ParameterType;
                }
                setItemParameterTypes[getItemParameters.Length] = this.getItemMethod.ReturnType;

                this.setItemMethod = this.getItemMethod.DeclaringType.GetMethod(
                    setItemName, BindingFlags.Public | BindingFlags.Instance, null, setItemParameterTypes, null);

                if (this.setItemMethod != null)
                {
                    //  Get the target object and all the setter's arguments 
                    //  (minus the actual value to be set).
                    this.targetObjectFunction = ExpressionUtilities.Compile<object>(callExpression.Object, expression.Parameters);

                    this.setItemArgumentFunctions = new Func<ActivityContext, object>[callExpression.Arguments.Count];
                    for (int i = 0; i < callExpression.Arguments.Count; i++)
                    {
                        // convert value types to objects since Linq doesn't do it automatically
                        Expression argument = callExpression.Arguments[i];
                        if (argument.Type.IsValueType)
                        {
                            argument = Expression.Convert(argument, TypeHelper.ObjectType);
                        }
                        this.setItemArgumentFunctions[i] = ExpressionUtilities.Compile<object>(argument, expression.Parameters);
                    }
                }
            }

            public override Location<T> CreateLocation(ActivityContext context)
            {
                object targetObject = null;
                object[] setItemArguments = null;

                if (this.setItemMethod != null)
                {
                    targetObject = this.targetObjectFunction(context);

                    setItemArguments = new object[this.setItemArgumentFunctions.Length];

                    for (int i = 0; i < this.setItemArgumentFunctions.Length; i++)
                    {
                        setItemArguments[i] = this.setItemArgumentFunctions[i](context);
                    }
                }

                return new IndexerLocation(this.indexerName, this.getItemMethod, this.setItemMethod, targetObject, setItemArguments);
            }

            [DataContract]
            internal class IndexerLocation : Location<T>
            {
                string indexerName;

                MethodInfo getItemMethod;

                MethodInfo setItemMethod;

                object targetObject;

                object[] setItemArguments;

                public IndexerLocation(string indexerName, MethodInfo getItemMethod, MethodInfo setItemMethod,
                    object targetObject, object[] getItemArguments)
                    : base()
                {
                    this.indexerName = indexerName;
                    this.getItemMethod = getItemMethod;
                    this.setItemMethod = setItemMethod;
                    this.targetObject = targetObject;
                    this.setItemArguments = getItemArguments;
                }

                [SuppressMessage(FxCop.Category.Usage, FxCop.Rule.DoNotRaiseReservedExceptionTypes,
                Justification = "Need to raise NullReferenceException to match expected failure case in workflows.")]
                public override T Value
                {
                    get
                    {
                        if (this.targetObject == null && !this.getItemMethod.IsStatic)
                        {
                            throw FxTrace.Exception.AsError(new NullReferenceException(SR.CannotDereferenceNull(this.getItemMethod.Name)));
                        }

                        return (T)this.getItemMethod.Invoke(this.targetObject, this.setItemArguments);
                    }

                    set
                    {

                        if (this.setItemMethod == null)
                        {
                            string targetObjectTypeName = this.targetObject.GetType().Name;
                            throw FxTrace.Exception.AsError(new InvalidOperationException(
                                SR.MissingSetAccessorForIndexer(this.indexerName, targetObjectTypeName)));
                        }

                        if (this.targetObject == null && !this.setItemMethod.IsStatic)
                        {
                            throw FxTrace.Exception.AsError(new NullReferenceException(SR.CannotDereferenceNull(this.setItemMethod.Name)));
                        }

                        object[] localSetItemArguments = new object[this.setItemArguments.Length + 1];
                        Array.ConstrainedCopy(this.setItemArguments, 0, localSetItemArguments, 0, this.setItemArguments.Length);
                        localSetItemArguments[localSetItemArguments.Length - 1] = value;

                        this.setItemMethod.Invoke(this.targetObject, localSetItemArguments);
                    }
                }

                [DataMember(Name = "indexerName")]
                internal string SerializedIndexerName
                {
                    get { return this.indexerName; }
                    set { this.indexerName = value; }
                }

                [DataMember(EmitDefaultValue = false, Name = "getItemMethod")]
                internal MethodInfo SerializedGetItemMethod
                {
                    get { return this.getItemMethod; }
                    set { this.getItemMethod = value; }
                }

                [DataMember(EmitDefaultValue = false, Name = "setItemMethod")]
                internal MethodInfo SerializedSetItemMethod
                {
                    get { return this.setItemMethod; }
                    set { this.setItemMethod = value; }
                }

                [DataMember(EmitDefaultValue = false, Name = "targetObject")]
                internal object SerializedTargetObject
                {
                    get { return this.targetObject; }
                    set { this.targetObject = value; }
                }

                [DataMember(EmitDefaultValue = false, Name = "setItemArguments")]
                internal object[] SerializedSetItemArguments
                {
                    get { return this.setItemArguments; }
                    set { this.setItemArguments = value; }
                }
            }
        }

        class MultidimensionalArrayLocationFactory<T> : LocationFactory<T>
        {
            Func<ActivityContext, Array> arrayFunction;
            Func<ActivityContext, int>[] indexFunctions;

            public MultidimensionalArrayLocationFactory(LambdaExpression expression)
            {
                Fx.Assert(expression.Body.NodeType == ExpressionType.Call, "Call expression required.");
                MethodCallExpression callExpression = (MethodCallExpression)expression.Body;

                this.arrayFunction = ExpressionUtilities.Compile<Array>(
                    callExpression.Object, expression.Parameters);

                this.indexFunctions = new Func<ActivityContext, int>[callExpression.Arguments.Count];
                for (int i = 0; i < this.indexFunctions.Length; i++)
                {
                    this.indexFunctions[i] = ExpressionUtilities.Compile<int>(
                        callExpression.Arguments[i], expression.Parameters);
                }
            }

            public override Location<T> CreateLocation(ActivityContext context)
            {
                int[] indices = new int[this.indexFunctions.Length];
                for (int i = 0; i < indices.Length; i++)
                {
                    indices[i] = this.indexFunctions[i](context);
                }
                return new MultidimensionalArrayLocation(this.arrayFunction(context), indices);
            }

            [DataContract]
            internal class MultidimensionalArrayLocation : Location<T>
            {
                Array array;

                int[] indices;

                public MultidimensionalArrayLocation(Array array, int[] indices)
                    : base()
                {
                    this.array = array;
                    this.indices = indices;
                }

                public override T Value
                {
                    get
                    {
                        return (T)this.array.GetValue(this.indices);
                    }

                    set
                    {
                        this.array.SetValue(value, this.indices);
                    }
                }

                [DataMember(Name = "array")]
                internal Array SerializedArray
                {
                    get { return this.array; }
                    set { this.array = value; }
                }

                [DataMember(Name = "indices")]
                internal int[] SerializedIndicess
                {
                    get { return this.indices; }
                    set { this.indices = value; }
                }
            }
        }

        class PropertyLocationFactory<T> : LocationFactory<T>
        {
            Func<ActivityContext, object> ownerFunction;
            PropertyInfo propertyInfo;
            LocationFactory parentFactory;

            public PropertyLocationFactory(LambdaExpression expression)
            {
                Fx.Assert(expression.Body.NodeType == ExpressionType.MemberAccess, "member access expression required");
                MemberExpression memberExpression = (MemberExpression)expression.Body;

                Fx.Assert(memberExpression.Member.MemberType == MemberTypes.Property, "property access expression expected");
                this.propertyInfo = (PropertyInfo)memberExpression.Member;

                if (memberExpression.Expression == null)
                {
                    // static property
                    this.ownerFunction = null;
                }
                else
                {
                    this.ownerFunction = ExpressionUtilities.Compile<object>(
                        Expression.Convert(memberExpression.Expression, TypeHelper.ObjectType), expression.Parameters);
                }

                if (this.propertyInfo.DeclaringType.IsValueType)
                {
                    // may want to set a struct, so we need to make an expression in order to set the parent
                    parentFactory = CreateParentReference(memberExpression.Expression, expression.Parameters);
                }
            }

            public override Location<T> CreateLocation(ActivityContext context)
            {
                object owner = null;
                if (this.ownerFunction != null)
                {
                    owner = this.ownerFunction(context);
                }

                Location parent = null;
                if (parentFactory != null)
                {
                    parent = parentFactory.CreateLocation(context);
                }
                return new PropertyLocation(this.propertyInfo, owner, parent);
            }

            [DataContract]
            internal class PropertyLocation : Location<T>
            {
                object owner;

                PropertyInfo propertyInfo;

                Location parent;

                public PropertyLocation(PropertyInfo propertyInfo, object owner, Location parent)
                    : base()
                {
                    this.propertyInfo = propertyInfo;
                    this.owner = owner;
                    this.parent = parent;
                }

                [SuppressMessage(FxCop.Category.Usage, FxCop.Rule.DoNotRaiseReservedExceptionTypes,
                Justification = "Need to raise NullReferenceException to match expected failure case in workflows.")]
                public override T Value
                {
                    get
                    {
                        // Only allow access to public properties, EXCEPT that Locations are top-level variables 
                        // from the other's perspective, not internal properties, so they're okay as a special case.
                        // E.g. "[N]" from the user's perspective is not accessing a nonpublic property, even though
                        // at an implementation level it is.
                        MethodInfo getMethodInfo = this.propertyInfo.GetGetMethod();
                        if (getMethodInfo == null && !TypeHelper.AreTypesCompatible(this.propertyInfo.DeclaringType, typeof(Location)))
                        {
                            throw FxTrace.Exception.AsError(new InvalidOperationException(SR.WriteonlyPropertyCannotBeRead(this.propertyInfo.DeclaringType, this.propertyInfo.Name)));
                        }

                        if (this.owner == null && (getMethodInfo == null || !getMethodInfo.IsStatic))
                        {
                            throw FxTrace.Exception.AsError(new NullReferenceException(SR.CannotDereferenceNull(this.propertyInfo.Name)));
                        }

                        // Okay, it's public
                        return (T)this.propertyInfo.GetValue(this.owner, null);
                    }

                    set
                    {
                        // Only allow access to public properties, EXCEPT that Locations are top-level variables 
                        // from the other's perspective, not internal properties, so they're okay as a special case.
                        // E.g. "[N]" from the user's perspective is not accessing a nonpublic property, even though
                        // at an implementation level it is.
                        MethodInfo setMethodInfo = this.propertyInfo.GetSetMethod();
                        if (setMethodInfo == null && !TypeHelper.AreTypesCompatible(this.propertyInfo.DeclaringType, typeof(Location)))
                        {
                            throw FxTrace.Exception.AsError(new InvalidOperationException(SR.ReadonlyPropertyCannotBeSet(this.propertyInfo.DeclaringType, this.propertyInfo.Name)));
                        }

                        if (this.owner == null && (setMethodInfo == null || !setMethodInfo.IsStatic))
                        {
                            throw FxTrace.Exception.AsError(new NullReferenceException(SR.CannotDereferenceNull(this.propertyInfo.Name)));
                        }

                        // Okay, it's public
                        this.propertyInfo.SetValue(this.owner, value, null);
                        if (this.parent != null)
                        {
                            // Looks like we are trying to set a property on a struct
                            // Calling SetValue simply sets the property on the local copy of the struct, which is not very helpful
                            // Since we have a copy, assign it back to the parent
                            this.parent.Value = this.owner;
                        }
                    }
                }

                [DataMember(EmitDefaultValue = false, Name = "owner")]
                internal object SerializedOwner
                {
                    get { return this.owner; }
                    set { this.owner = value; }
                }

                [DataMember(Name = "propertyInfo")]
                internal PropertyInfo SerializedPropertyInfo
                {
                    get { return this.propertyInfo; }
                    set { this.propertyInfo = value; }
                }

                [DataMember(EmitDefaultValue = false, Name = "parent")]
                internal Location SerializedParent
                {
                    get { return this.parent; }
                    set { this.parent = value; }
                }
            }
        }

        // Returns true if it changed the expression (newExpression != expression).
        // If it returns false then newExpression is set equal to expression.
        // This method uses the publicAccessor parameter to generate violations (workflow
        // artifacts which are not visible) and to generate inline references
        // (references at a higher scope which can be resolved at runtime).
        public static bool TryRewriteLambdaExpression(Expression expression, out Expression newExpression, CodeActivityPublicEnvironmentAccessor publicAccessor, bool isLocationExpression = false)
        {
            newExpression = expression;

            if (expression == null)
            {
                return false;
            }

            // Share some local declarations across the switch
            Expression left = null;
            Expression right = null;
            Expression other = null;
            bool hasChanged = false;
            IList<Expression> expressionList = null;
            IList<ElementInit> initializerList = null;
            IList<MemberBinding> bindingList = null;
            MethodCallExpression methodCall = null;
            BinaryExpression binaryExpression = null;
            NewArrayExpression newArray = null;
            UnaryExpression unaryExpression = null;

            switch (expression.NodeType)
            {
                case ExpressionType.Add:
                case ExpressionType.AddChecked:
                case ExpressionType.And:
                case ExpressionType.AndAlso:
                case ExpressionType.Coalesce:
                case ExpressionType.Divide:
                case ExpressionType.Equal:
                case ExpressionType.ExclusiveOr:
                case ExpressionType.GreaterThan:
                case ExpressionType.GreaterThanOrEqual:
                case ExpressionType.LeftShift:
                case ExpressionType.LessThan:
                case ExpressionType.LessThanOrEqual:
                case ExpressionType.Modulo:
                case ExpressionType.Multiply:
                case ExpressionType.MultiplyChecked:
                case ExpressionType.NotEqual:
                case ExpressionType.Or:
                case ExpressionType.OrElse:
                case ExpressionType.Power:
                case ExpressionType.RightShift:
                case ExpressionType.Subtract:
                case ExpressionType.SubtractChecked:
                    binaryExpression = (BinaryExpression)expression;

                    hasChanged |= TryRewriteLambdaExpression(binaryExpression.Left, out left, publicAccessor);
                    hasChanged |= TryRewriteLambdaExpression(binaryExpression.Right, out right, publicAccessor);
                    hasChanged |= TryRewriteLambdaExpression(binaryExpression.Conversion, out other, publicAccessor);

                    if (hasChanged)
                    {
                        newExpression = Expression.MakeBinary(
                            binaryExpression.NodeType,
                            left,
                            right,
                            binaryExpression.IsLiftedToNull,
                            binaryExpression.Method,
                            (LambdaExpression)other);
                    }
                    break;

                case ExpressionType.Conditional:
                    ConditionalExpression conditional = (ConditionalExpression)expression;

                    hasChanged |= TryRewriteLambdaExpression(conditional.Test, out other, publicAccessor);
                    hasChanged |= TryRewriteLambdaExpression(conditional.IfTrue, out left, publicAccessor);
                    hasChanged |= TryRewriteLambdaExpression(conditional.IfFalse, out right, publicAccessor);

                    if (hasChanged)
                    {
                        newExpression = Expression.Condition(
                            other,
                            left,
                            right);
                    }
                    break;

                case ExpressionType.Constant:
                    break;

                case ExpressionType.Invoke:
                    InvocationExpression invocation = (InvocationExpression)expression;

                    hasChanged |= TryRewriteLambdaExpression(invocation.Expression, out other, publicAccessor);
                    hasChanged |= TryRewriteLambdaExpressionCollection(invocation.Arguments, out expressionList, publicAccessor);

                    if (hasChanged)
                    {
                        newExpression = Expression.Invoke(
                            other,
                            expressionList);
                    }
                    break;

                case ExpressionType.Lambda:
                    LambdaExpression lambda = (LambdaExpression)expression;

                    hasChanged |= TryRewriteLambdaExpression(lambda.Body, out other, publicAccessor, isLocationExpression);

                    if (hasChanged)
                    {
                        newExpression = Expression.Lambda(
                            lambda.Type,
                            other,
                            lambda.Parameters);
                    }
                    break;

                case ExpressionType.ListInit:
                    ListInitExpression listInit = (ListInitExpression)expression;

                    hasChanged |= TryRewriteLambdaExpression(listInit.NewExpression, out other, publicAccessor);
                    hasChanged |= TryRewriteLambdaExpressionInitializersCollection(listInit.Initializers, out initializerList, publicAccessor);

                    if (hasChanged)
                    {
                        newExpression = Expression.ListInit(
                            (NewExpression)other,
                            initializerList);
                    }
                    break;

                case ExpressionType.Parameter:
                    break;

                case ExpressionType.MemberAccess:
                    MemberExpression memberExpression = (MemberExpression)expression;

                    // When creating a location for a member on a struct, we also need a location
                    // for the struct (so we don't just set the member on a copy of the struct)
                    bool subTreeIsLocationExpression = isLocationExpression && memberExpression.Member.DeclaringType.IsValueType;

                    hasChanged |= TryRewriteLambdaExpression(memberExpression.Expression, out other, publicAccessor, subTreeIsLocationExpression);

                    if (hasChanged)
                    {
                        newExpression = Expression.MakeMemberAccess(
                            other,
                            memberExpression.Member);
                    }
                    break;

                case ExpressionType.MemberInit:
                    MemberInitExpression memberInit = (MemberInitExpression)expression;

                    hasChanged |= TryRewriteLambdaExpression(memberInit.NewExpression, out other, publicAccessor);
                    hasChanged |= TryRewriteLambdaExpressionBindingsCollection(memberInit.Bindings, out bindingList, publicAccessor);

                    if (hasChanged)
                    {
                        newExpression = Expression.MemberInit(
                            (NewExpression)other,
                            bindingList);
                    }
                    break;

                case ExpressionType.ArrayIndex:
                    // ArrayIndex can be a MethodCallExpression or a BinaryExpression
                    methodCall = expression as MethodCallExpression;
                    if (methodCall != null)
                    {
                        hasChanged |= TryRewriteLambdaExpression(methodCall.Object, out other, publicAccessor);
                        hasChanged |= TryRewriteLambdaExpressionCollection(methodCall.Arguments, out expressionList, publicAccessor);

                        if (hasChanged)
                        {
                            newExpression = Expression.ArrayIndex(
                                other,
                                expressionList);
                        }
                    }
                    else
                    {
                        binaryExpression = (BinaryExpression)expression;

                        hasChanged |= TryRewriteLambdaExpression(binaryExpression.Left, out left, publicAccessor);
                        hasChanged |= TryRewriteLambdaExpression(binaryExpression.Right, out right, publicAccessor);

                        if (hasChanged)
                        {
                            newExpression = Expression.ArrayIndex(
                                left,
                                right);
                        }
                    }
                    break;

                case ExpressionType.Call:
                    methodCall = (MethodCallExpression)expression;

                    // TryRewriteMethodCall does all the real work
                    hasChanged = TryRewriteMethodCall(methodCall, out newExpression, publicAccessor, isLocationExpression);
                    break;

                case ExpressionType.NewArrayInit:
                    newArray = (NewArrayExpression)expression;

                    hasChanged |= TryRewriteLambdaExpressionCollection(newArray.Expressions, out expressionList, publicAccessor);

                    if (hasChanged)
                    {
                        newExpression = Expression.NewArrayInit(
                            newArray.Type.GetElementType(),
                            expressionList);
                    }
                    break;

                case ExpressionType.NewArrayBounds:
                    newArray = (NewArrayExpression)expression;

                    hasChanged |= TryRewriteLambdaExpressionCollection(newArray.Expressions, out expressionList, publicAccessor);

                    if (hasChanged)
                    {
                        newExpression = Expression.NewArrayBounds(
                            newArray.Type.GetElementType(),
                            expressionList);
                    }
                    break;

                case ExpressionType.New:
                    NewExpression objectCreationExpression = (NewExpression)expression;

                    if (objectCreationExpression.Constructor == null)
                    {
                        // must be creating a valuetype
                        Fx.Assert(objectCreationExpression.Arguments.Count == 0, "NewExpression with null Constructor but some arguments");
                    }
                    else
                    {
                        hasChanged |= TryRewriteLambdaExpressionCollection(objectCreationExpression.Arguments, out expressionList, publicAccessor);

                        if (hasChanged)
                        {
                            newExpression = objectCreationExpression.Update(expressionList);
                        }
                    }
                    break;

                case ExpressionType.TypeIs:
                    TypeBinaryExpression typeBinary = (TypeBinaryExpression)expression;

                    hasChanged |= TryRewriteLambdaExpression(typeBinary.Expression, out other, publicAccessor);

                    if (hasChanged)
                    {
                        newExpression = Expression.TypeIs(
                            other,
                            typeBinary.TypeOperand);
                    }
                    break;

                case ExpressionType.ArrayLength:
                case ExpressionType.Convert:
                case ExpressionType.ConvertChecked:
                case ExpressionType.Negate:
                case ExpressionType.NegateChecked:
                case ExpressionType.Not:
                case ExpressionType.Quote:
                case ExpressionType.TypeAs:
                    unaryExpression = (UnaryExpression)expression;

                    hasChanged |= TryRewriteLambdaExpression(unaryExpression.Operand, out left, publicAccessor);

                    if (hasChanged)
                    {
                        newExpression = Expression.MakeUnary(
                            unaryExpression.NodeType,
                            left,
                            unaryExpression.Type,
                            unaryExpression.Method);
                    }
                    break;

                case ExpressionType.UnaryPlus:
                    unaryExpression = (UnaryExpression)expression;

                    hasChanged |= TryRewriteLambdaExpression(unaryExpression.Operand, out left, publicAccessor);

                    if (hasChanged)
                    {
                        newExpression = Expression.UnaryPlus(
                            left,
                            unaryExpression.Method);
                    }
                    break;

                // Expression Tree V2.0 types. This is due to the hosted VB compiler generating ET V2.0 nodes.

                case ExpressionType.Block:
                    BlockExpression block = (BlockExpression)expression;

                    hasChanged |= TryRewriteLambdaExpressionCollection(block.Expressions, out expressionList, publicAccessor);

                    if (hasChanged)
                    {
                        // Parameter collections are never rewritten
                        newExpression = Expression.Block(block.Variables, expressionList);
                    }
                    break;

                case ExpressionType.Assign:
                    binaryExpression = (BinaryExpression)expression;

                    hasChanged |= TryRewriteLambdaExpression(binaryExpression.Left, out left, publicAccessor);
                    hasChanged |= TryRewriteLambdaExpression(binaryExpression.Right, out right, publicAccessor);

                    if (hasChanged)
                    {
                        newExpression = Expression.Assign(left, right);
                    }
                    break;
            }

            return hasChanged;
        }

        static bool TryRewriteLambdaExpressionBindingsCollection(IList<MemberBinding> bindings, out IList<MemberBinding> newBindings, CodeActivityPublicEnvironmentAccessor publicAccessor)
        {
            IList<MemberBinding> temporaryBindings = null;

            for (int i = 0; i < bindings.Count; i++)
            {
                MemberBinding binding = bindings[i];

                MemberBinding newBinding;
                if (TryRewriteMemberBinding(binding, out newBinding, publicAccessor))
                {
                    if (temporaryBindings == null)
                    {
                        // We initialize this list with the unchanged bindings
                        temporaryBindings = new List<MemberBinding>(bindings.Count);

                        for (int j = 0; j < i; j++)
                        {
                            temporaryBindings.Add(bindings[j]);
                        }
                    }
                }

                // At this point newBinding is either the updated binding (if
                // rewrite returned true) or the original binding (if false
                // was returned)
                if (temporaryBindings != null)
                {
                    temporaryBindings.Add(newBinding);
                }
            }

            if (temporaryBindings != null)
            {
                newBindings = temporaryBindings;
                return true;
            }
            else
            {
                newBindings = bindings;
                return false;
            }
        }

        static bool TryRewriteMemberBinding(MemberBinding binding, out MemberBinding newBinding, CodeActivityPublicEnvironmentAccessor publicAccessor)
        {
            newBinding = binding;

            bool hasChanged = false;
            Expression other = null;
            IList<ElementInit> initializerList = null;
            IList<MemberBinding> bindingList = null;

            switch (binding.BindingType)
            {
                case MemberBindingType.Assignment:
                    MemberAssignment assignment = (MemberAssignment)binding;

                    hasChanged |= TryRewriteLambdaExpression(assignment.Expression, out other, publicAccessor);

                    if (hasChanged)
                    {
                        newBinding = Expression.Bind(assignment.Member, other);
                    }
                    break;

                case MemberBindingType.ListBinding:
                    MemberListBinding list = (MemberListBinding)binding;

                    hasChanged |= TryRewriteLambdaExpressionInitializersCollection(list.Initializers, out initializerList, publicAccessor);

                    if (hasChanged)
                    {
                        newBinding = Expression.ListBind(list.Member, initializerList);
                    }
                    break;

                case MemberBindingType.MemberBinding:
                    MemberMemberBinding member = (MemberMemberBinding)binding;

                    hasChanged |= TryRewriteLambdaExpressionBindingsCollection(member.Bindings, out bindingList, publicAccessor);

                    if (hasChanged)
                    {
                        newBinding = Expression.MemberBind(member.Member, bindingList);
                    }
                    break;
            }

            return hasChanged;
        }


        static bool TryRewriteLambdaExpressionCollection(IList<Expression> expressions, out IList<Expression> newExpressions, CodeActivityPublicEnvironmentAccessor publicAccessor)
        {
            IList<Expression> temporaryExpressions = null;

            for (int i = 0; i < expressions.Count; i++)
            {
                Expression expression = expressions[i];

                Expression newExpression;
                if (TryRewriteLambdaExpression(expression, out newExpression, publicAccessor))
                {
                    if (temporaryExpressions == null)
                    {
                        // We initialize the list by copying all of the unchanged
                        // expressions over
                        temporaryExpressions = new List<Expression>(expressions.Count);

                        for (int j = 0; j < i; j++)
                        {
                            temporaryExpressions.Add(expressions[j]);
                        }
                    }
                }

                // newExpression will either be set to the new expression (true was
                // returned) or the original expression (false was returned)
                if (temporaryExpressions != null)
                {
                    temporaryExpressions.Add(newExpression);
                }
            }

            if (temporaryExpressions != null)
            {
                newExpressions = temporaryExpressions;
                return true;
            }
            else
            {
                newExpressions = expressions;
                return false;
            }
        }

        static bool TryRewriteLambdaExpressionInitializersCollection(IList<ElementInit> initializers, out IList<ElementInit> newInitializers, CodeActivityPublicEnvironmentAccessor publicAccessor)
        {
            IList<ElementInit> temporaryInitializers = null;

            for (int i = 0; i < initializers.Count; i++)
            {
                ElementInit elementInit = initializers[i];

                IList<Expression> newExpressions;
                if (TryRewriteLambdaExpressionCollection(elementInit.Arguments, out newExpressions, publicAccessor))
                {
                    if (temporaryInitializers == null)
                    {
                        // We initialize the list by copying all of the unchanged
                        // initializers over
                        temporaryInitializers = new List<ElementInit>(initializers.Count);

                        for (int j = 0; j < i; j++)
                        {
                            temporaryInitializers.Add(initializers[j]);
                        }
                    }

                    elementInit = Expression.ElementInit(elementInit.AddMethod, newExpressions);
                }

                if (temporaryInitializers != null)
                {
                    temporaryInitializers.Add(elementInit);
                }
            }

            if (temporaryInitializers != null)
            {
                newInitializers = temporaryInitializers;
                return true;
            }
            else
            {
                newInitializers = initializers;
                return false;
            }
        }

        static bool TryGetInlinedArgumentReference(MethodCallExpression originalExpression, Expression argumentExpression, out LocationReference inlinedReference, CodeActivityPublicEnvironmentAccessor publicAccessor, bool isLocationExpression)
        {
            inlinedReference = null;

            Argument argument = null;
            object tempArgument;

            if (CustomMemberResolver(argumentExpression, out tempArgument) && tempArgument is Argument)
            {
                argument = (Argument)tempArgument;
            }
            else
            {
                try
                {
                    Expression<Func<Argument>> argumentLambda = Expression.Lambda<Func<Argument>>(argumentExpression);
                    Func<Argument> argumentFunc = argumentLambda.Compile();
                    argument = argumentFunc();
                }
                catch (Exception e)
                {
                    if (Fx.IsFatal(e))
                    {
                        throw;
                    }

                    publicAccessor.ActivityMetadata.AddValidationError(SR.ErrorExtractingValuesForLambdaRewrite(argumentExpression.Type, originalExpression, e));
                    return false;
                }
            }

            if (argument == null)
            {
                if (argumentExpression.NodeType == ExpressionType.MemberAccess)
                {
                    MemberExpression memberExpression = (MemberExpression)argumentExpression;
                    if (memberExpression.Member.MemberType == MemberTypes.Property)
                    {
                        RuntimeArgument runtimeArgument = ActivityUtilities.FindArgument(memberExpression.Member.Name, publicAccessor.ActivityMetadata.CurrentActivity);

                        if (runtimeArgument != null && TryGetInlinedReference(publicAccessor, runtimeArgument, isLocationExpression, out inlinedReference))
                        {
                            return true;
                        }
                    }
                }

                publicAccessor.ActivityMetadata.AddValidationError(SR.ErrorExtractingValuesForLambdaRewrite(argumentExpression.Type, originalExpression, SR.SubexpressionResultWasNull(argumentExpression.Type)));
                return false;
            }
            else
            {
                if (argument.RuntimeArgument == null || !TryGetInlinedReference(publicAccessor, argument.RuntimeArgument, isLocationExpression, out inlinedReference))
                {
                    publicAccessor.ActivityMetadata.AddValidationError(SR.ErrorExtractingValuesForLambdaRewrite(argumentExpression.Type, originalExpression, SR.SubexpressionResultWasNotVisible(argumentExpression.Type)));
                    return false;
                }
                else
                {
                    return true;
                }
            }
        }

        static bool TryRewriteArgumentGetCall(MethodCallExpression originalExpression, Type returnType, out Expression newExpression, CodeActivityPublicEnvironmentAccessor publicAccessor, bool isLocationExpression)
        {
            // We verify that this is a method we are expecting (single parameter
            // of type ActivityContext).  If not, we won't rewrite it at all
            // and will just let it fail at runtime.
            ReadOnlyCollection<Expression> argumentExpressions = originalExpression.Arguments;

            if (argumentExpressions.Count == 1)
            {
                Expression contextExpression = argumentExpressions[0];

                if (contextExpression.Type == activityContextType)
                {
                    LocationReference inlinedReference;
                    if (TryGetInlinedArgumentReference(originalExpression, originalExpression.Object, out inlinedReference, publicAccessor, isLocationExpression))
                    {
                        newExpression = Expression.Call(contextExpression, activityContextGetValueGenericMethod.MakeGenericMethod(returnType), Expression.Constant(inlinedReference, typeof(LocationReference)));
                        return true;
                    }
                }
            }

            newExpression = originalExpression;
            return false;
        }

        static bool TryRewriteArgumentGetLocationCall(MethodCallExpression originalExpression, Type returnType, out Expression newExpression, CodeActivityPublicEnvironmentAccessor publicAccessor)
        {
            // We verify that this is a method we are expecting (single parameter
            // of type ActivityContext).  If not, we won't rewrite it at all
            // and will just let it fail at runtime.
            ReadOnlyCollection<Expression> argumentExpressions = originalExpression.Arguments;

            if (argumentExpressions.Count == 1)
            {
                Expression contextExpression = argumentExpressions[0];

                if (contextExpression.Type == activityContextType)
                {
                    LocationReference inlinedReference;
                    if (TryGetInlinedArgumentReference(originalExpression, originalExpression.Object, out inlinedReference, publicAccessor, true))
                    {
                        if (returnType == null)
                        {
                            newExpression = Expression.Call(Expression.Constant(inlinedReference, typeof(LocationReference)), locationReferenceGetLocationMethod, contextExpression);
                        }
                        else
                        {
                            newExpression = Expression.Call(contextExpression, activityContextGetLocationGenericMethod.MakeGenericMethod(returnType), Expression.Constant(inlinedReference, typeof(LocationReference)));
                        }

                        return true;
                    }
                }
            }

            newExpression = originalExpression;
            return false;
        }

        static bool TryRewriteLocationReferenceSubclassGetCall(MethodCallExpression originalExpression, Type returnType, out Expression newExpression, CodeActivityPublicEnvironmentAccessor publicAccessor, bool isLocationExpression)
        {
            // We verify that this is a method we are expecting (single parameter
            // of type ActivityContext).  If not, we won't rewrite it at all
            // and will just let it fail at runtime.
            ReadOnlyCollection<Expression> argumentExpressions = originalExpression.Arguments;

            if (argumentExpressions.Count == 1)
            {
                Expression contextExpression = argumentExpressions[0];

                if (contextExpression.Type == activityContextType)
                {
                    LocationReference inlinedReference;
                    if (TryGetInlinedLocationReference(originalExpression, originalExpression.Object, out inlinedReference, publicAccessor, isLocationExpression))
                    {
                        newExpression = Expression.Call(contextExpression, activityContextGetValueGenericMethod.MakeGenericMethod(returnType), Expression.Constant(inlinedReference, typeof(LocationReference)));
                        return true;
                    }
                }
            }

            newExpression = originalExpression;
            return false;
        }

        static bool TryRewriteLocationReferenceSubclassGetLocationCall(MethodCallExpression originalExpression, Type returnType, out Expression newExpression, CodeActivityPublicEnvironmentAccessor publicAccessor)
        {
            // We verify that this is a method we are expecting (single parameter
            // of type ActivityContext).  If not, we won't rewrite it at all
            // and will just let it fail at runtime.
            ReadOnlyCollection<Expression> argumentExpressions = originalExpression.Arguments;

            if (argumentExpressions.Count == 1)
            {
                Expression contextExpression = argumentExpressions[0];

                if (contextExpression.Type == activityContextType)
                {
                    LocationReference inlinedReference;
                    if (TryGetInlinedLocationReference(originalExpression, originalExpression.Object, out inlinedReference, publicAccessor, true))
                    {
                        if (returnType == null)
                        {
                            newExpression = Expression.Call(Expression.Constant(inlinedReference, typeof(LocationReference)), locationReferenceGetLocationMethod, originalExpression.Arguments[0]);
                        }
                        else
                        {
                            newExpression = Expression.Call(contextExpression, activityContextGetLocationGenericMethod.MakeGenericMethod(returnType), Expression.Constant(inlinedReference, typeof(LocationReference)));
                        }

                        return true;
                    }
                }
            }

            newExpression = originalExpression;
            return false;
        }

        static bool CustomMemberResolver(Expression expression, out object memberValue)
        {
            memberValue = null;

            switch (expression.NodeType)
            {
                case ExpressionType.Constant:
                    ConstantExpression constantExpression = expression as ConstantExpression;
                    memberValue = constantExpression.Value;
                    // memberValue = null means:
                    // 1. The expression does not follow the common patterns(local, field or property)
                    // which we optimize(do not compile using Linq compiler) and try to resolve directly in this method 
                    // OR 2. The expression actually resolved to null.
                    // In both these cases, we compile the expression and run it so that we have a single error path.
                    return memberValue != null;

                case ExpressionType.MemberAccess:
                    MemberExpression memberExpression = expression as MemberExpression;
                    if (memberExpression.Expression != null)
                    {
                        CustomMemberResolver(memberExpression.Expression, out memberValue);
                        memberValue = GetMemberValue(memberExpression.Member, memberValue);
                    }
                    return memberValue != null;

                default:
                    return false;
            }
        }

        static object GetMemberValue(MemberInfo memberInfo, object owner)
        {
            if (owner == null)
            {
                // We do not want to throw any exceptions here. We 
                // will just do the regular compile in this case.
                return null;
            }

            MemberTypes memberType = memberInfo.MemberType;
            if (memberType == MemberTypes.Property)
            {
                PropertyInfo propertyInfo = memberInfo as PropertyInfo;
                return propertyInfo.GetValue(owner, null);

            }
            else if (memberType == MemberTypes.Field)
            {
                FieldInfo fieldInfo = memberInfo as FieldInfo;
                return fieldInfo.GetValue(owner);
            }
            return null;
        }

        static bool TryGetInlinedLocationReference(MethodCallExpression originalExpression, Expression locationReferenceExpression, out LocationReference inlinedReference, CodeActivityPublicEnvironmentAccessor publicAccessor, bool isLocationExpression)
        {
            inlinedReference = null;

            LocationReference locationReference = null;
            object tempLocationReference;
            if (CustomMemberResolver(locationReferenceExpression, out tempLocationReference) && tempLocationReference is LocationReference)
            {
                locationReference = (LocationReference)tempLocationReference;
            }
            else
            {
                try
                {
                    Expression<Func<LocationReference>> locationReferenceLambda = Expression.Lambda<Func<LocationReference>>(locationReferenceExpression);
                    Func<LocationReference> locationReferenceFunc = locationReferenceLambda.Compile();
                    locationReference = locationReferenceFunc();
                }
                catch (Exception e)
                {
                    if (Fx.IsFatal(e))
                    {
                        throw;
                    }

                    publicAccessor.ActivityMetadata.AddValidationError(SR.ErrorExtractingValuesForLambdaRewrite(locationReferenceExpression.Type, originalExpression, e));
                    return false;
                }
            }

            if (locationReference == null)
            {
                publicAccessor.ActivityMetadata.AddValidationError(SR.ErrorExtractingValuesForLambdaRewrite(locationReferenceExpression.Type, originalExpression, SR.SubexpressionResultWasNull(locationReferenceExpression.Type)));
                return false;
            }
            else if (!TryGetInlinedReference(publicAccessor, locationReference, isLocationExpression, out inlinedReference))
            {
                publicAccessor.ActivityMetadata.AddValidationError(SR.ErrorExtractingValuesForLambdaRewrite(locationReferenceExpression.Type, originalExpression, SR.SubexpressionResultWasNotVisible(locationReferenceExpression.Type)));
                return false;
            }
            else
            {
                return true;
            }
        }

        static bool TryRewriteActivityContextGetValueCall(MethodCallExpression originalExpression, Type returnType, out Expression newExpression, CodeActivityPublicEnvironmentAccessor publicAccessor, bool isLocationExpression)
        {
            newExpression = originalExpression;

            LocationReference inlinedReference = null;

            // We verify that this is a method we are expecting (single parameter
            // of either LocationReference or Argument type).  If not, we won't
            // rewrite it at all and will just let it fail at runtime.
            ReadOnlyCollection<Expression> argumentExpressions = originalExpression.Arguments;

            if (argumentExpressions.Count == 1)
            {
                Expression parameterExpression = argumentExpressions[0];

                if (TypeHelper.AreTypesCompatible(parameterExpression.Type, typeof(Argument)))
                {
                    if (!TryGetInlinedArgumentReference(originalExpression, parameterExpression, out inlinedReference, publicAccessor, isLocationExpression))
                    {
                        publicAccessor.ActivityMetadata.AddValidationError(SR.ErrorExtractingValuesForLambdaRewrite(parameterExpression.Type, originalExpression, SR.SubexpressionResultWasNotVisible(parameterExpression.Type)));
                        return false;
                    }
                }
                else if (TypeHelper.AreTypesCompatible(parameterExpression.Type, typeof(LocationReference)))
                {
                    if (!TryGetInlinedLocationReference(originalExpression, parameterExpression, out inlinedReference, publicAccessor, isLocationExpression))
                    {
                        publicAccessor.ActivityMetadata.AddValidationError(SR.ErrorExtractingValuesForLambdaRewrite(parameterExpression.Type, originalExpression, SR.SubexpressionResultWasNotVisible(parameterExpression.Type)));
                        return false;
                    }
                }
            }

            if (inlinedReference != null)
            {
                newExpression = Expression.Call(originalExpression.Object, activityContextGetValueGenericMethod.MakeGenericMethod(returnType), Expression.Constant(inlinedReference, typeof(LocationReference)));
                return true;
            }

            return false;
        }

        static bool TryRewriteActivityContextGetLocationCall(MethodCallExpression originalExpression, Type returnType, out Expression newExpression, CodeActivityPublicEnvironmentAccessor publicAccessor)
        {
            // We verify that this is a method we are expecting (single parameter
            // of LocationReference type).  If not, we won't rewrite it at all
            // and will just let it fail at runtime.
            ReadOnlyCollection<Expression> argumentExpressions = originalExpression.Arguments;

            if (argumentExpressions.Count == 1)
            {
                Expression locationReference = argumentExpressions[0];

                if (TypeHelper.AreTypesCompatible(locationReference.Type, locationReferenceType))
                {
                    LocationReference inlinedReference;
                    if (TryGetInlinedLocationReference(originalExpression, originalExpression.Arguments[0], out inlinedReference, publicAccessor, true))
                    {
                        newExpression = Expression.Call(originalExpression.Object, activityContextGetLocationGenericMethod.MakeGenericMethod(returnType), Expression.Constant(inlinedReference, typeof(LocationReference)));
                        return true;
                    }
                }
            }

            newExpression = originalExpression;
            return false;
        }

        // Local perf testing leads to the following preference for matching method infos:
        //   * object.ReferenceEquals(info1, info2) is the fastest
        //   * info1.Name == "MethodName" is a close second
        //   * object.ReferenceEquals(info1, type.GetMethod("MethodName")) is very slow by comparison
        //   * object.ReferenceEquals(info1, genericMethodDefinition.MakeGenericMethod(typeParameter)) is also very
        //     slow by comparison
        static bool TryRewriteMethodCall(MethodCallExpression methodCall, out Expression newExpression, CodeActivityPublicEnvironmentAccessor publicAccessor, bool isLocationExpression)
        {
            // NOTE: Here's the set of method call conversions/rewrites that we are
            // performing.  The left hand side of the "=>" is the pattern that from
            // the original expression using the following shorthand for instances of
            // types:
            //    ctx = ActivityContext
            //    inArg = InArgument<T>
            //    inOutArg = InOutArgument<T>
            //    outArg = OutArgument<T>
            //    arg = Argument
            //    runtimeArg = RuntimeArgument
            //    ref = LocationReference (and subclasses)
            // 
            // The right hand side of the "=>" shows the rewritten method call.  When
            // the same symbol shows up on both sides that means we will use the same
            // expression (IE - ref.Get(ctx) => ctx.GetValue<T>(inline) means that the
            // expression for ctx on the left side is the same expression we should use
            // on the right side).
            //
            // "inline" is used in the right hand side to signify the inlined location
            // reference.  Except where explicitly called out, this is the inlined
            // version of the LocationReference (or subclass) from the left hand side.
            //
            // If the left-hand-side method is Get/GetValue methods, and isLocationExpression
            // is false, we create a read-only InlinedLocationReference, which will produce
            // a RuntimeArgument<T> with ArgumentDirection.In.
            // Otherwise, we create a full-access InlinedLocationReference, which will produce
            // a RuntimeArgument<Location<T>> with ArgumentDirection.In.
            //
            // Finally, "(new)" signifies that the method we are looking for hides a
            // method with the same signature on one of the base classes.
            //
            // ActivityContext
            //    ctx.GetValue<T>(inArg) => ctx.GetValue<T>(inline)  inline = Inline(inArg.RuntimeArgument)
            //    ctx.GetValue<T>(inOutArg) => ctx.GetValue<T>(inline)  inline = Inline(inOutArg.RuntimeArgument)
            //    ctx.GetValue<T>(outArg) => ctx.GetValue<T>(inline)  inline = Inline(outArg.RuntimeArgument)
            //    ctx.GetValue(arg) => ctx.GetValue<object>(inline)  inline = Inline(arg.RuntimeArgument)
            //    ctx.GetValue(runtimeArg) => ctx.GetValue<object>(inline)
            //    ctx.GetValue<T>(ref) => ctx.GetValue<T>(inline)
            //    ctx.GetLocation<T>(ref) => ctx.GetLocation<T>(inline)
            //
            // LocationReference
            //    ref.GetLocation(ctx) => inline.GetLocation(ctx)
            //
            // RuntimeArgument : LocationReference
            //    ref.Get(ctx) => ctx.GetValue<object>(inline)
            //    ref.Get<T>(ctx) => ctx.GetValue<T>(inline)
            //
            // Argument
            //    arg.Get(ctx) => ctx.GetValue<object>(inline)  inline = Inline(arg.RuntimeArgument)
            //    arg.Get<T>(ctx) => ctx.GetValue<T>(inline)  inline = Inline(arg.RuntimeArgument)
            //    arg.GetLocation(ctx) => inline.GetLocation(ctx)  inline = Inline(arg.RuntimeArgument)
            //
            // InArgument<T> : Argument
            //    (new)  arg.Get(ctx) => ctx.GetValue<T>(inline)  inline = Inline(arg.RuntimeArgument)
            //
            // InOutArgument<T> : Argument
            //    (new)  arg.Get(ctx) => ctx.GetValue<T>(inline)  inline = Inline(arg.RuntimeArgument)
            //    (new)  arg.GetLocation<T>(ctx) => ctx.GetLocation<T>(inline)  inline = Inline(arg.RuntimeArgument)
            //
            // OutArgument<T> : Argument
            //    (new)  arg.Get(ctx) => ctx.GetValue<T>(inline)  inline = Inline(arg.RuntimeArgument)
            //    (new)  arg.GetLocation<T>(ctx) => ctx.GetLocation<T>(inline)  inline = Inline(arg.RuntimeArgument)
            //
            // Variable : LocationReference
            //    ref.Get(ctx) => ctx.GetValue<object>(inline)
            //
            // Variable<T> : Variable
            //    (new)  ref.Get(ctx) => ctx.GetValue<T>(inline)
            //    (new)  ref.GetLocation(ctx) => ctx.GetLocation<T>(inline)
            //
            // DelegateArgument : LocationReference
            //    ref.Get(ctx) => ctx.GetValue<object>(inline)
            //
            // DelegateInArgument<T> : DelegateArgument
            //    (new) ref.Get(ctx) => ctx.GetValue<T>(inline)
            //
            // DelegateOutArgument<T> : DelegateArgument
            //    (new) ref.Get(ctx) => ctx.GetValue<T>(inline)
            //    (new) ref.GetLocation(ctx) => ctx.GetLocation<T>(inline)

            MethodInfo targetMethod = methodCall.Method;
            Type targetObjectType = targetMethod.DeclaringType;

            if (targetObjectType.IsGenericType)
            {
                // All of these methods are non-generic methods (they don't introduce a new
                // type parameter), but they do make use of the type parameter of the 
                // generic declaring type.  Because of that we can't do MethodInfo comparison
                // and fall back to string comparison.
                Type targetObjectGenericType = targetObjectType.GetGenericTypeDefinition();

                if (targetObjectGenericType == variableGenericType)
                {
                    if (targetMethod.Name == "Get")
                    {
                        return TryRewriteLocationReferenceSubclassGetCall(methodCall, targetObjectType.GetGenericArguments()[0], out newExpression, publicAccessor, isLocationExpression);
                    }
                    else if (targetMethod.Name == "GetLocation")
                    {
                        return TryRewriteLocationReferenceSubclassGetLocationCall(methodCall, targetObjectType.GetGenericArguments()[0], out newExpression, publicAccessor);
                    }
                }
                else if (targetObjectGenericType == inArgumentGenericType)
                {
                    if (targetMethod.Name == "Get")
                    {
                        return TryRewriteArgumentGetCall(methodCall, targetObjectType.GetGenericArguments()[0], out newExpression, publicAccessor, isLocationExpression);
                    }
                }
                else if (targetObjectGenericType == outArgumentGenericType || targetObjectGenericType == inOutArgumentGenericType)
                {
                    if (targetMethod.Name == "Get")
                    {
                        return TryRewriteArgumentGetCall(methodCall, targetObjectType.GetGenericArguments()[0], out newExpression, publicAccessor, isLocationExpression);
                    }
                    else if (targetMethod.Name == "GetLocation")
                    {
                        return TryRewriteArgumentGetLocationCall(methodCall, targetObjectType.GetGenericArguments()[0], out newExpression, publicAccessor);
                    }
                }
                else if (targetObjectGenericType == delegateInArgumentGenericType)
                {
                    if (targetMethod.Name == "Get")
                    {
                        return TryRewriteLocationReferenceSubclassGetCall(methodCall, targetObjectType.GetGenericArguments()[0], out newExpression, publicAccessor, isLocationExpression);
                    }
                }
                else if (targetObjectGenericType == delegateOutArgumentGenericType)
                {
                    if (targetMethod.Name == "Get")
                    {
                        return TryRewriteLocationReferenceSubclassGetCall(methodCall, targetObjectType.GetGenericArguments()[0], out newExpression, publicAccessor, isLocationExpression);
                    }
                    else if (targetMethod.Name == "GetLocation")
                    {
                        return TryRewriteLocationReferenceSubclassGetLocationCall(methodCall, targetObjectType.GetGenericArguments()[0], out newExpression, publicAccessor);
                    }
                }
            }
            else
            {
                if (targetObjectType == variableType)
                {
                    if (object.ReferenceEquals(targetMethod, variableGetMethod))
                    {
                        return TryRewriteLocationReferenceSubclassGetCall(methodCall, TypeHelper.ObjectType, out newExpression, publicAccessor, isLocationExpression);
                    }
                }
                else if (targetObjectType == delegateArgumentType)
                {
                    if (object.ReferenceEquals(targetMethod, delegateArgumentGetMethod))
                    {
                        return TryRewriteLocationReferenceSubclassGetCall(methodCall, TypeHelper.ObjectType, out newExpression, publicAccessor, isLocationExpression);
                    }
                }
                else if (targetObjectType == activityContextType)
                {
                    // We use the string comparison for these two because
                    // we have several overloads of GetValue (some generic,
                    // some not) and GetLocation is a generic method
                    if (targetMethod.Name == "GetValue")
                    {
                        Type returnType = TypeHelper.ObjectType;

                        if (targetMethod.IsGenericMethod)
                        {
                            returnType = targetMethod.GetGenericArguments()[0];
                        }

                        return TryRewriteActivityContextGetValueCall(methodCall, returnType, out newExpression, publicAccessor, isLocationExpression);
                    }
                    else if (targetMethod.IsGenericMethod && targetMethod.Name == "GetLocation")
                    {
                        return TryRewriteActivityContextGetLocationCall(methodCall, targetMethod.GetGenericArguments()[0], out newExpression, publicAccessor);
                    }
                }
                else if (targetObjectType == locationReferenceType)
                {
                    if (object.ReferenceEquals(targetMethod, locationReferenceGetLocationMethod))
                    {
                        return TryRewriteLocationReferenceSubclassGetLocationCall(methodCall, null, out newExpression, publicAccessor);
                    }
                }
                else if (targetObjectType == runtimeArgumentType)
                {
                    // We use string comparison here because we can
                    // match both overloads with a single check.
                    if (targetMethod.Name == "Get")
                    {
                        Type returnType = TypeHelper.ObjectType;

                        if (targetMethod.IsGenericMethod)
                        {
                            returnType = targetMethod.GetGenericArguments()[0];
                        }

                        return TryRewriteLocationReferenceSubclassGetCall(methodCall, returnType, out newExpression, publicAccessor, isLocationExpression);
                    }
                }
                else if (targetObjectType == argumentType)
                {
                    // We use string comparison here because we can
                    // match both overloads with a single check.
                    if (targetMethod.Name == "Get")
                    {
                        Type returnType = TypeHelper.ObjectType;

                        if (targetMethod.IsGenericMethod)
                        {
                            returnType = targetMethod.GetGenericArguments()[0];
                        }

                        return TryRewriteArgumentGetCall(methodCall, returnType, out newExpression, publicAccessor, isLocationExpression);
                    }
                    else if (object.ReferenceEquals(targetMethod, argumentGetLocationMethod))
                    {
                        return TryRewriteArgumentGetLocationCall(methodCall, null, out newExpression, publicAccessor);
                    }
                }
            }

            // Here's the code for a method call that isn't on our "special" list
            newExpression = methodCall;

            Expression objectExpression;
            IList<Expression> expressionList;

            bool hasChanged = TryRewriteLambdaExpression(methodCall.Object, out objectExpression, publicAccessor);
            hasChanged |= TryRewriteLambdaExpressionCollection(methodCall.Arguments, out expressionList, publicAccessor);

            if (hasChanged)
            {
                newExpression = Expression.Call(objectExpression, targetMethod, expressionList);
            }

            return hasChanged;
        }

        internal static Expression RewriteNonCompiledExpressionTree(LambdaExpression originalLambdaExpression)
        {
            ExpressionTreeRewriter expressionVisitor = new ExpressionTreeRewriter();
            return expressionVisitor.Visit(Expression.Lambda(
                typeof(Func<,>).MakeGenericType(typeof(ActivityContext), originalLambdaExpression.ReturnType),
                originalLambdaExpression.Body, 
                new ParameterExpression[] { ExpressionUtilities.RuntimeContextParameter }));
        }
    }
}