[Fixes #819] Display LoaderExceptions in ReflectionTypeLoadException

src/Microsoft.AspNetCore.Hosting/Internal/HostingLoggerExtensions.cs

@@ -6,6 +6,7 @@ using System.Collections;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Globalization;
+using System.Reflection;
 using Microsoft.AspNetCore.Http;
 using Microsoft.Extensions.Logging;
 
@@ -51,9 +52,20 @@ namespace Microsoft.AspNetCore.Hosting.Internal
 
         public static void ApplicationError(this ILogger logger, Exception exception)
         {
+            var message = "Application startup exception";
+
+            var reflectionTypeLoadException = exception as ReflectionTypeLoadException;
+            if (reflectionTypeLoadException != null)
+            {
+                foreach (var ex in reflectionTypeLoadException.LoaderExceptions)
+                {
+                    message = message + Environment.NewLine + ex.Message;
+                }
+            }
+
             logger.LogCritical(
                 eventId: LoggerEventIds.ApplicationStartupException,
-                message: "Application startup exception",
+                message: message,
                 exception: exception);
         }
 

src/Microsoft.AspNetCore.Hosting/Startup/ConventionBasedStartup.cs

@@ -2,6 +2,8 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Reflection;
+using System.Runtime.ExceptionServices;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Hosting.Internal;
 using Microsoft.Extensions.DependencyInjection;
@@ -19,12 +21,36 @@ namespace Microsoft.AspNetCore.Hosting
         
         public void Configure(IApplicationBuilder app)
         {
-            _methods.ConfigureDelegate(app);
+            try
+            {
+                _methods.ConfigureDelegate(app);
+            }
+            catch (Exception ex)
+            {
+                if (ex is TargetInvocationException)
+                {
+                    ExceptionDispatchInfo.Capture(ex.InnerException).Throw();
+                }
+
+                throw;
+            }
         }
 
         public IServiceProvider ConfigureServices(IServiceCollection services)
         {
-            return _methods.ConfigureServicesDelegate(services);
+            try
+            {
+                return _methods.ConfigureServicesDelegate(services);
+            }
+            catch (Exception ex)
+            {
+                if (ex is TargetInvocationException)
+                {
+                    ExceptionDispatchInfo.Capture(ex.InnerException).Throw();
+                }
+
+                throw;
+            }
         }
     }
 }

src/Microsoft.AspNetCore.Hosting/Startup/StartupExceptionPage.cs

@@ -103,7 +103,7 @@ namespace Microsoft.AspNetCore.Hosting
                 if (!string.IsNullOrEmpty(typeName) && !string.IsNullOrEmpty(type.Namespace))
                 {
                     builder.Append($@"<span class=""faded"">at {HtmlEncodeAndReplaceLineBreaks(type.Namespace)}</span>");
-                    typeName = typeName.Substring(type.Namespace.Length + 1);
+                    typeName = typeName.Substring(type.Namespace.Length);
                 }
 
                 builder.Append(HtmlEncodeAndReplaceLineBreaks(typeName));
@@ -302,12 +302,12 @@ namespace Microsoft.AspNetCore.Hosting
         private static IEnumerable<Exception> FlattenAndReverseExceptionTree(Exception ex)
         {
             // ReflectionTypeLoadException is special because the details are in 
-            // a the LoaderExceptions property
+            // the LoaderExceptions property
             var typeLoadException = ex as ReflectionTypeLoadException;
             if (typeLoadException != null)
             {
                 var typeLoadExceptions = new List<Exception>();
-                foreach (Exception loadException in typeLoadException.LoaderExceptions)
+                foreach (var loadException in typeLoadException.LoaderExceptions)
                 {
                     typeLoadExceptions.AddRange(FlattenAndReverseExceptionTree(loadException));
                 }