diff --git a/src/Microsoft.AspNet.Mvc.Core/DefaultControllerFactory.cs b/src/Microsoft.AspNet.Mvc.Core/DefaultControllerFactory.cs
index 3d40e3d855..b7c582235a 100644
--- a/src/Microsoft.AspNet.Mvc.Core/DefaultControllerFactory.cs
+++ b/src/Microsoft.AspNet.Mvc.Core/DefaultControllerFactory.cs
@@ -1,6 +1,6 @@
 using System;
-using System.Reflection;
 using Microsoft.AspNet.DependencyInjection;
+using Microsoft.AspNet.Mvc.Core;
 using Microsoft.AspNet.Mvc.ModelBinding;
 using Microsoft.AspNet.Mvc.Rendering;
 
@@ -22,23 +22,18 @@ namespace Microsoft.AspNet.Mvc
             var actionDescriptor = actionContext.ActionDescriptor as ReflectedActionDescriptor;
             if (actionDescriptor == null)
             {
-                return null;
+                throw new ArgumentException(
+                    Resources.FormatDefaultControllerFactory_ActionDescriptorMustBeReflected(
+                        typeof(ReflectedActionDescriptor)),
+                    "actionContext");
             }
 
-            try
-            {
-                var controller = _activator.CreateInstance(_serviceProvider, actionDescriptor.ControllerDescriptor.ControllerTypeInfo.AsType());
+            var controller = _activator.CreateInstance(_serviceProvider, actionDescriptor.ControllerDescriptor.ControllerTypeInfo.AsType());
 
-                // TODO: How do we feed the controller with context (need DI improvements)
-                InitializeController(controller, actionContext);
+            // TODO: How do we feed the controller with context (need DI improvements)
+            InitializeController(controller, actionContext);
 
-                return controller;
-            } // TODO: Should we not catch it here?
-            catch (ReflectionTypeLoadException)
-            {
-            }
-
-            return null;
+            return controller;
         }
 
         public void ReleaseController(object controller)
diff --git a/src/Microsoft.AspNet.Mvc.Core/Properties/Resources.Designer.cs b/src/Microsoft.AspNet.Mvc.Core/Properties/Resources.Designer.cs
index 9e54509e08..862d4280d6 100644
--- a/src/Microsoft.AspNet.Mvc.Core/Properties/Resources.Designer.cs
+++ b/src/Microsoft.AspNet.Mvc.Core/Properties/Resources.Designer.cs
@@ -201,7 +201,7 @@ namespace Microsoft.AspNet.Mvc.Core
         {
             return string.Format(CultureInfo.CurrentCulture, GetString("ViewComponent_InvalidReturnValue"), p0, p1, p2);
         }
-        
+
         /// <summary>
         /// Replacing the action context is not supported.
         /// </summary>
@@ -234,6 +234,54 @@ namespace Microsoft.AspNet.Mvc.Core
             return string.Format(CultureInfo.CurrentCulture, GetString("ActionInvokerFactory_CouldNotCreateInvoker"), p0);
         }
 
+        /// <summary>
+        /// The action descriptor must be of type '{0}'.
+        /// </summary>
+        internal static string DefaultControllerFactory_ActionDescriptorMustBeReflected
+        {
+            get { return GetString("DefaultControllerFactory_ActionDescriptorMustBeReflected"); }
+        }
+
+        /// <summary>
+        /// The action descriptor must be of type '{0}'.
+        /// </summary>
+        internal static string FormatDefaultControllerFactory_ActionDescriptorMustBeReflected(object p0)
+        {
+            return string.Format(CultureInfo.CurrentCulture, GetString("DefaultControllerFactory_ActionDescriptorMustBeReflected"), p0);
+        }
+
+        /// <summary>
+        /// The '{0}' property of '{1}' must not be null.
+        /// </summary>
+        internal static string PropertyOfTypeCannotBeNull
+        {
+            get { return GetString("PropertyOfTypeCannotBeNull"); }
+        }
+
+        /// <summary>
+        /// The '{0}' property of '{1}' must not be null.
+        /// </summary>
+        internal static string FormatPropertyOfTypeCannotBeNull(object p0, object p1)
+        {
+            return string.Format(CultureInfo.CurrentCulture, GetString("PropertyOfTypeCannotBeNull"), p0, p1);
+        }
+
+        /// <summary>
+        /// The '{0}' must return a non null '{1}'.
+        /// </summary>
+        internal static string MethodMustReturnNotNullValue
+        {
+            get { return GetString("MethodMustReturnNotNullValue"); }
+        }
+
+        /// <summary>
+        /// The '{0}' must return a non null '{1}'.
+        /// </summary>
+        internal static string FormatMethodMustReturnNotNullValue(object p0, object p1)
+        {
+            return string.Format(CultureInfo.CurrentCulture, GetString("MethodMustReturnNotNullValue"), p0, p1);
+        }
+
         private static string GetString(string name, params string[] formatterNames)
         {
             var value = _resourceManager.GetString(name);
diff --git a/src/Microsoft.AspNet.Mvc.Core/ReflectedActionInvoker.cs b/src/Microsoft.AspNet.Mvc.Core/ReflectedActionInvoker.cs
index f955187d02..9e5b31701a 100644
--- a/src/Microsoft.AspNet.Mvc.Core/ReflectedActionInvoker.cs
+++ b/src/Microsoft.AspNet.Mvc.Core/ReflectedActionInvoker.cs
@@ -1,8 +1,10 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Reflection;
 using System.Threading.Tasks;
 using Microsoft.AspNet.DependencyInjection;
+using Microsoft.AspNet.Mvc.Core;
 using Microsoft.AspNet.Mvc.Filters;
 using Microsoft.AspNet.Mvc.ModelBinding;
 
@@ -21,12 +23,12 @@ namespace Microsoft.AspNet.Mvc
         private readonly List<IActionFilter> _actionFilters = new List<IActionFilter>();
         private readonly List<IActionResultFilter> _actionResultFilters = new List<IActionResultFilter>();
 
-        public ReflectedActionInvoker(ActionContext actionContext,
-                                      ReflectedActionDescriptor descriptor,
-                                      IActionResultFactory actionResultFactory,
-                                      IControllerFactory controllerFactory,
-                                      IActionBindingContextProvider bindingContextProvider,
-                                      INestedProviderManager<FilterProviderContext> filterProvider)
+        public ReflectedActionInvoker([NotNull] ActionContext actionContext,
+                                      [NotNull] ReflectedActionDescriptor descriptor,
+                                      [NotNull] IActionResultFactory actionResultFactory,
+                                      [NotNull] IControllerFactory controllerFactory,
+                                      [NotNull] IActionBindingContextProvider bindingContextProvider,
+                                      [NotNull] INestedProviderManager<FilterProviderContext> filterProvider)
         {
             _actionContext = actionContext;
             _descriptor = descriptor;
@@ -34,6 +36,14 @@ namespace Microsoft.AspNet.Mvc
             _controllerFactory = controllerFactory;
             _bindingProvider = bindingContextProvider;
             _filterProvider = filterProvider;
+
+            if (descriptor.MethodInfo == null)
+            {
+                throw new ArgumentException(
+                    Resources.FormatPropertyOfTypeCannotBeNull(typeof(ReflectedActionDescriptor),
+                                                               "MethodInfo"),
+                    "descriptor");
+            }
         }
 
         public async Task InvokeActionAsync()
@@ -54,67 +64,56 @@ namespace Microsoft.AspNet.Mvc
 
             if (controller == null)
             {
-                // TODO: See if these return 404s should turn into 500s
-                actionResult = new HttpStatusCodeResult(404);
+                throw new InvalidOperationException(
+                    Resources.FormatMethodMustReturnNotNullValue(typeof(IControllerFactory),
+                                                                 "controller"));
             }
-            else
-            {
-                var method = _descriptor.MethodInfo;
 
-                if (method == null)
+            if (_authorizationFilters.Count > 0)
+            {
+                var authZEndPoint = new AuthorizationFilterEndPoint();
+                _authorizationFilters.Add(authZEndPoint);
+
+                var authZContext = new AuthorizationFilterContext(_actionContext, filterMetaItems);
+                var authZPipeline = new FilterPipelineBuilder<AuthorizationFilterContext>(_authorizationFilters, authZContext);
+
+                await authZPipeline.InvokeAsync();
+
+                if (authZContext.ActionResult == null &&
+                    !authZContext.HasFailed &&
+                    authZEndPoint.EndPointCalled)
                 {
-                    // TODO: See if these return 404s should turn into 500s
-                    actionResult = new HttpStatusCodeResult(404);
+                    actionResult = null;
                 }
                 else
                 {
-                    if (_authorizationFilters.Count > 0)
-                    {
-                        var authZEndPoint = new AuthorizationFilterEndPoint();
-                        _authorizationFilters.Add(authZEndPoint);
-
-                        var authZContext = new AuthorizationFilterContext(_actionContext, filterMetaItems);
-                        var authZPipeline = new FilterPipelineBuilder<AuthorizationFilterContext>(_authorizationFilters, authZContext);
-
-                        await authZPipeline.InvokeAsync();
-
-                        if (authZContext.ActionResult == null &&
-                            !authZContext.HasFailed &&
-                            authZEndPoint.EndPointCalled)
-                        {
-                            actionResult = null;
-                        }
-                        else
-                        {
-                            // User cleaned out the result but we failed or short circuited the end point.
-                            actionResult = authZContext.ActionResult ?? new HttpStatusCodeResult(401);
-                        }
-                    }
-                    else
-                    {
-                        actionResult = null;
-                    }
-
-                    if (actionResult == null)
-                    {
-                        var parameterValues = await GetParameterValues(_actionContext.ModelState);
-
-                        var actionFilterContext = new ActionFilterContext(_actionContext,
-                                                                          filterMetaItems,
-                                                                          parameterValues);
-
-                        var actionEndPoint = new ReflectedActionFilterEndPoint(_actionResultFactory, controller);
-
-                        _actionFilters.Add(actionEndPoint);
-                        var actionFilterPipeline = new FilterPipelineBuilder<ActionFilterContext>(_actionFilters,
-                            actionFilterContext);
-
-                        await actionFilterPipeline.InvokeAsync();
-
-                        actionResult = actionFilterContext.ActionResult;
-                    }
+                    // User cleaned out the result but we failed or short circuited the end point.
+                    actionResult = authZContext.ActionResult ?? new HttpStatusCodeResult(401);
                 }
             }
+            else
+            {
+                actionResult = null;
+            }
+
+            if (actionResult == null)
+            {
+                var parameterValues = await GetParameterValues(_actionContext.ModelState);
+
+                var actionFilterContext = new ActionFilterContext(_actionContext,
+                                                                  filterMetaItems,
+                                                                  parameterValues);
+
+                var actionEndPoint = new ReflectedActionFilterEndPoint(_actionResultFactory, controller);
+
+                _actionFilters.Add(actionEndPoint);
+                var actionFilterPipeline = new FilterPipelineBuilder<ActionFilterContext>(_actionFilters,
+                    actionFilterContext);
+
+                await actionFilterPipeline.InvokeAsync();
+
+                actionResult = actionFilterContext.ActionResult;
+            }
 
             var actionResultFilterContext = new ActionResultFilterContext(_actionContext, filterMetaItems, actionResult);
             var actionResultFilterEndPoint = new ActionResultFilterEndPoint();
diff --git a/src/Microsoft.AspNet.Mvc.Core/Resources.resx b/src/Microsoft.AspNet.Mvc.Core/Resources.resx
index 86c20a3c52..0921753a93 100644
--- a/src/Microsoft.AspNet.Mvc.Core/Resources.resx
+++ b/src/Microsoft.AspNet.Mvc.Core/Resources.resx
@@ -159,4 +159,13 @@
   <data name="ActionInvokerFactory_CouldNotCreateInvoker" xml:space="preserve">
     <value>An action invoker could not be created for action '{0}'.</value>
   </data>
+  <data name="DefaultControllerFactory_ActionDescriptorMustBeReflected" xml:space="preserve">
+    <value>The action descriptor must be of type '{0}'.</value>
+  </data>
+  <data name="PropertyOfTypeCannotBeNull" xml:space="preserve">
+    <value>The '{0}' property of '{1}' must not be null.</value>
+  </data>
+  <data name="MethodMustReturnNotNullValue" xml:space="preserve">
+    <value>The '{0}' must return a non null '{1}'.</value>
+  </data>
 </root>