public void Execute()
        {
            var reactiveUI = ModuleDefinition.AssemblyReferences.Where(x => x.Name == "ReactiveUI").OrderByDescending(x => x.Version).FirstOrDefault();
            if (reactiveUI == null)
            {
                LogInfo("Could not find assembly: ReactiveUI (" + string.Join(", ", ModuleDefinition.AssemblyReferences.Select(x => x.Name)) + ")");
                return;
            }
            LogInfo(string.Format("{0} {1}", reactiveUI.Name, reactiveUI.Version));
            var helpers = ModuleDefinition.AssemblyReferences.Where(x => x.Name == "ReactiveUI.Fody.Helpers").OrderByDescending(x => x.Version).FirstOrDefault();
            if (helpers == null)
                throw new Exception("Could not find assembly: ReactiveUI.Fody.Helpers (" + string.Join(", ", ModuleDefinition.AssemblyReferences.Select(x => x.Name)) + ")");
            LogInfo(string.Format("{0} {1}", helpers.Name, helpers.Version));

            var reactiveObject = ModuleDefinition.FindType("ReactiveUI", "ReactiveObject", reactiveUI);

            // The types we will scan are subclasses of ReactiveObject
            var targetTypes = ModuleDefinition.GetAllTypes().Where(x => x.BaseType != null && reactiveObject.IsAssignableFrom(x.BaseType));

            var observableAsPropertyHelper = ModuleDefinition.FindType("ReactiveUI", "ObservableAsPropertyHelper`1", reactiveUI, "T");
            var observableAsPropertyAttribute = ModuleDefinition.FindType("ReactiveUI.Fody.Helpers", "ObservableAsPropertyAttribute", helpers);
            var observableAsPropertyHelperGetValue = ModuleDefinition.Import(observableAsPropertyHelper.Resolve().Properties.Single(x => x.Name == "Value").GetMethod);
            var exceptionType = ModuleDefinition.Import(typeof(Exception));
            var exceptionConstructor = ModuleDefinition.Import(exceptionType.Resolve().GetConstructors().Single(x => x.Parameters.Count == 1));

            foreach (var targetType in targetTypes)
            {
                foreach (var property in targetType.Properties.Where(x => x.IsDefined(observableAsPropertyAttribute)).ToArray())
                {
                    var genericObservableAsPropertyHelper = observableAsPropertyHelper.MakeGenericInstanceType(property.PropertyType);
                    var genericObservableAsPropertyHelperGetValue = observableAsPropertyHelperGetValue.Bind(genericObservableAsPropertyHelper);
                    ModuleDefinition.Import(genericObservableAsPropertyHelperGetValue);

                    // Declare a field to store the property value
                    var field = new FieldDefinition("$" + property.Name, FieldAttributes.Private, genericObservableAsPropertyHelper);
                    targetType.Fields.Add(field);

                    // It's an auto-property, so remove the generated field
                    if (property.SetMethod != null)
                    {
                        // Remove old field (the generated backing field for the auto property)
                        var oldField = (FieldReference)property.GetMethod.Body.Instructions.Where(x => x.Operand is FieldReference).Single().Operand;
                        var oldFieldDefinition = oldField.Resolve();
                        targetType.Fields.Remove(oldFieldDefinition);                        

                        // Re-implement setter to throw an exception
                        property.SetMethod.Body = new MethodBody(property.SetMethod);
                        property.SetMethod.Body.Emit(il =>
                        {
                            il.Emit(OpCodes.Ldstr, "Never call the setter of an ObservabeAsPropertyHelper property.");
                            il.Emit(OpCodes.Newobj, exceptionConstructor);
                            il.Emit(OpCodes.Throw);
                            il.Emit(OpCodes.Ret);
                        });
                    }

                    property.GetMethod.Body = new MethodBody(property.GetMethod);
                    property.GetMethod.Body.Emit(il =>
                    {
                        il.Emit(OpCodes.Ldarg_0);                                               // this
                        il.Emit(OpCodes.Ldfld, field.BindDefinition(targetType));               // pop -> this.$PropertyName
                        il.Emit(OpCodes.Callvirt, genericObservableAsPropertyHelperGetValue);   // pop -> this.$PropertyName.Value
                        il.Emit(OpCodes.Ret);                                                   // Return the value that is on the stack
                    });
                }
            }
        }         
        public void Execute()
        {
            var reactiveUI = ModuleDefinition.AssemblyReferences.Where(x => x.Name == "ReactiveUI").OrderByDescending(x => x.Version).FirstOrDefault();
            if (reactiveUI == null)
            {
                LogInfo("Could not find assembly: ReactiveUI (" + string.Join(", ", ModuleDefinition.AssemblyReferences.Select(x => x.Name)) + ")");
                return;
            }
            LogInfo(string.Format("{0} {1}", reactiveUI.Name, reactiveUI.Version));
            var helpers = ModuleDefinition.AssemblyReferences.Where(x => x.Name == "ReactiveUI.Fody.Helpers").OrderByDescending(x => x.Version).FirstOrDefault();
            if (helpers == null)
                throw new Exception("Could not find assembly: ReactiveUI.Fody.Helpers (" + string.Join(", ", ModuleDefinition.AssemblyReferences.Select(x => x.Name)) + ")");
            LogInfo(string.Format("{0} {1}", helpers.Name, helpers.Version));
            var reactiveObject = new TypeReference("ReactiveUI", "IReactiveObject", ModuleDefinition, reactiveUI);
            var targetTypes = ModuleDefinition.GetAllTypes().Where(x => x.BaseType != null && reactiveObject.IsAssignableFrom(x.BaseType)).ToArray();
            var reactiveObjectExtensions = new TypeReference("ReactiveUI", "IReactiveObjectExtensions", ModuleDefinition, reactiveUI).Resolve();
            if (reactiveObjectExtensions == null)
                throw new Exception("reactiveObjectExtensions is null");

            var raiseAndSetIfChangedMethod = ModuleDefinition.Import(reactiveObjectExtensions.Methods.Single(x => x.Name == "RaiseAndSetIfChanged"));
            if (raiseAndSetIfChangedMethod == null)
                throw new Exception("raiseAndSetIfChangedMethod is null");

            var reactiveAttribute = ModuleDefinition.FindType("ReactiveUI.Fody.Helpers", "ReactiveAttribute", helpers);
            if (reactiveAttribute == null)
                throw new Exception("reactiveAttribute is null");

            foreach (var targetType in targetTypes)
            {
                foreach (var property in targetType.Properties.Where(x => x.IsDefined(reactiveAttribute)).ToArray())
                {
                    // Declare a field to store the property value
                    var field = new FieldDefinition("$" + property.Name, FieldAttributes.Private, property.PropertyType);
                    targetType.Fields.Add(field);

                    // Remove old field (the generated backing field for the auto property)
                    var oldField = (FieldReference)property.GetMethod.Body.Instructions.Where(x => x.Operand is FieldReference).Single().Operand;
                    var oldFieldDefinition = oldField.Resolve();
                    targetType.Fields.Remove(oldFieldDefinition);

                    // See if there exists an initializer for the auto-property
                    var constructors = targetType.Methods.Where(x => x.IsConstructor);
                    foreach (var constructor in constructors)
                    {
                        var fieldAssignment = constructor.Body.Instructions.SingleOrDefault(x => Equals(x.Operand, oldFieldDefinition) || Equals(x.Operand, oldField));
                        if (fieldAssignment != null)
                        {
                            // Replace field assignment with a property set (the stack semantics are the same for both, 
                            // so happily we don't have to manipulate the bytecode any further.)
                            var setterCall = constructor.Body.GetILProcessor().Create(property.SetMethod.IsVirtual ? OpCodes.Callvirt : OpCodes.Call, property.SetMethod);
                            constructor.Body.GetILProcessor().Replace(fieldAssignment, setterCall);
                        }
                    }

                    // Build out the getter which simply returns the value of the generated field
                    property.GetMethod.Body = new MethodBody(property.GetMethod);
                    property.GetMethod.Body.Emit(il =>
                    {
                        il.Emit(OpCodes.Ldarg_0);                                   // this
                        il.Emit(OpCodes.Ldfld, field.BindDefinition(targetType));   // pop -> this.$PropertyName
                        il.Emit(OpCodes.Ret);                                       // Return the field value that is lying on the stack
                    });

                    TypeReference genericTargetType = targetType;
                    if (targetType.HasGenericParameters)
                    {
                        var genericDeclaration = new GenericInstanceType(targetType);
                        foreach (var parameter in targetType.GenericParameters)
                        {
                            genericDeclaration.GenericArguments.Add(parameter);
                        }
                        genericTargetType = genericDeclaration;
                    }
                    
                    var methodReference = raiseAndSetIfChangedMethod.MakeGenericMethod(genericTargetType, property.PropertyType);

                    // Build out the setter which fires the RaiseAndSetIfChanged method
                    property.SetMethod.Body = new MethodBody(property.SetMethod);
                    property.SetMethod.Body.Emit(il =>
                    {
                        il.Emit(OpCodes.Ldarg_0);                                   // this
                        il.Emit(OpCodes.Ldarg_0);                                   // this
                        il.Emit(OpCodes.Ldflda, field.BindDefinition(targetType));  // pop -> this.$PropertyName
                        il.Emit(OpCodes.Ldarg_1);                                   // value
                        il.Emit(OpCodes.Ldstr, property.Name);                      // "PropertyName"
                        il.Emit(OpCodes.Call, methodReference);                     // pop * 4 -> this.RaiseAndSetIfChanged(this.$PropertyName, value, "PropertyName")
                        il.Emit(OpCodes.Pop);                                       // We don't care about the result of RaiseAndSetIfChanged, so pop it off the stack (stack is now empty)
                        il.Emit(OpCodes.Ret);                                       // Return out of the function
                    });
                }
            }
        }