Adding unknown nuget package to project.json dependencies shows "Object reference not set to an instance of object" in Error List

[BillHiebert]

1. Start VS & create an ASP.NET 5 project
2. Add "aaa" : "" to project.json dependencies

Error list shows "Object reference not set to an instance of object"

[BillHiebert]

Callstack:

Microsoft.Framework.Runtime.dll!Microsoft.Framework.Runtime.UnresolvedDependencyProvider.GetDescription(Microsoft.Framework.Runtime.LibraryRange libraryRange, System.Runtime.Versioning.FrameworkName targetFramework) Unknown
Microsoft.Framework.Runtime.dll!Microsoft.Framework.Runtime.WalkContext.Resolve(System.Collections.Generic.Dictionary<Microsoft.Framework.Runtime.LibraryRange,Microsoft.Framework.Runtime.WalkContext.Item> resolvedItems, System.Collections.Generic.IEnumerable<Microsoft.Framework.Runtime.IDependencyProvider> providers, Microsoft.Framework.Runtime.LibraryRange packageKey, System.Runtime.Versioning.FrameworkName frameworkName) Unknown
Microsoft.Framework.Runtime.dll!Microsoft.Framework.Runtime.WalkContext.Walk.AnonymousMethod__0(Microsoft.Framework.Runtime.WalkContext.Node node) Unknown
Microsoft.Framework.Runtime.dll!Microsoft.Framework.Runtime.WalkContext.ForEach.AnonymousMethod__0(Microsoft.Framework.Runtime.WalkContext.Node node, int _) Unknown
Microsoft.Framework.Runtime.dll!Microsoft.Framework.Runtime.WalkContext.ForEach(Microsoft.Framework.Runtime.WalkContext.Node root, int state, System.Func<Microsoft.Framework.Runtime.WalkContext.Node,int,int> visitor) Unknown
Microsoft.Framework.Runtime.dll!Microsoft.Framework.Runtime.WalkContext.ForEach(Microsoft.Framework.Runtime.WalkContext.Node root, System.Action<Microsoft.Framework.Runtime.WalkContext.Node> visitor) Unknown
Microsoft.Framework.Runtime.dll!Microsoft.Framework.Runtime.WalkContext.Walk(System.Collections.Generic.IEnumerable<Microsoft.Framework.Runtime.IDependencyProvider> dependencyResolvers, string name, NuGet.SemanticVersion version, System.Runtime.Versioning.FrameworkName frameworkName) Unknown
Microsoft.Framework.Runtime.dll!Microsoft.Framework.Runtime.DependencyWalker.Walk(string name, NuGet.SemanticVersion version, System.Runtime.Versioning.FrameworkName targetFramework) Unknown
Microsoft.Framework.DesignTimeHost.dll!Microsoft.Framework.DesignTimeHost.ApplicationContext.GetApplicationHostContext.AnonymousMethod__0(Microsoft.Framework.Runtime.CacheContext ctx) Unknown
Microsoft.Framework.Runtime.dll!Microsoft.Framework.Runtime.CacheExtensions.Get<System.__Canon>.AnonymousMethod__0(Microsoft.Framework.Runtime.CacheContext ctx) Unknown
Microsoft.Framework.Runtime.dll!Microsoft.Framework.Runtime.Cache.CreateEntry(object k, System.Func<Microsoft.Framework.Runtime.CacheContext,object> acquire) Unknown
Microsoft.Framework.Runtime.dll!Microsoft.Framework.Runtime.Cache.AddEntry.AnonymousMethod__0() Unknown
mscorlib.dll!System.Lazy<Microsoft.Framework.Runtime.Cache.CacheEntry>.CreateValue() Unknown
mscorlib.dll!System.Lazy<Microsoft.Framework.Runtime.Cache.CacheEntry>.LazyInitValue() Unknown
mscorlib.dll!System.Lazy<Microsoft.Framework.Runtime.Cache.CacheEntry>.Value.get() Unknown
Microsoft.Framework.Runtime.dll!Microsoft.Framework.Runtime.Cache.Get(object key, System.Func<Microsoft.Framework.Runtime.CacheContext,object> factory) Unknown
Microsoft.Framework.Runtime.dll!Microsoft.Framework.Runtime.CacheExtensions.Get<Microsoft.Framework.Runtime.ApplicationHostContext>(Microsoft.Framework.Runtime.ICache cache, object key, System.Func<Microsoft.Framework.Runtime.CacheContext,Microsoft.Framework.Runtime.ApplicationHostContext> factory) Unknown
Microsoft.Framework.DesignTimeHost.dll!Microsoft.Framework.DesignTimeHost.ApplicationContext.GetApplicationHostContext(Microsoft.Framework.Runtime.Project project, string configuration, System.Runtime.Versioning.FrameworkName frameworkName, bool useRuntimeLoadContextFactory) Unknown
Microsoft.Framework.DesignTimeHost.dll!Microsoft.Framework.DesignTimeHost.ApplicationContext.ResolveProjectDepencies.AnonymousMethod__0(Microsoft.Framework.Runtime.CacheContext ctx) Unknown
Microsoft.Framework.Runtime.dll!Microsoft.Framework.Runtime.CacheExtensions.Get<System.__Canon>.AnonymousMethod__0(Microsoft.Framework.Runtime.CacheContext ctx) Unknown
Microsoft.Framework.Runtime.dll!Microsoft.Framework.Runtime.Cache.CreateEntry(object k, System.Func<Microsoft.Framework.Runtime.CacheContext,object> acquire) Unknown
Microsoft.Framework.Runtime.dll!Microsoft.Framework.Runtime.Cache.AddEntry.AnonymousMethod__0() Unknown
mscorlib.dll!System.Lazy<Microsoft.Framework.Runtime.Cache.CacheEntry>.CreateValue() Unknown
mscorlib.dll!System.Lazy<Microsoft.Framework.Runtime.Cache.CacheEntry>.LazyInitValue() Unknown
mscorlib.dll!System.Lazy<Microsoft.Framework.Runtime.Cache.CacheEntry>.Value.get() Unknown
Microsoft.Framework.Runtime.dll!Microsoft.Framework.Runtime.Cache.Get(object key, System.Func<Microsoft.Framework.Runtime.CacheContext,object> factory) Unknown
Microsoft.Framework.Runtime.dll!Microsoft.Framework.Runtime.CacheExtensions.Get<Microsoft.Framework.DesignTimeHost.ApplicationContext.DependencyInfo>(Microsoft.Framework.Runtime.ICache cache, object key, System.Func<Microsoft.Framework.Runtime.CacheContext,Microsoft.Framework.DesignTimeHost.ApplicationContext.DependencyInfo> factory) Unknown
Microsoft.Framework.DesignTimeHost.dll!Microsoft.Framework.DesignTimeHost.ApplicationContext.ResolveProjectDepencies(Microsoft.Framework.Runtime.Project project, string configuration, System.Runtime.Versioning.FrameworkName frameworkName) Unknown
Microsoft.Framework.DesignTimeHost.dll!Microsoft.Framework.DesignTimeHost.ApplicationContext.DoInitialWork(string appPath, string configuration, bool triggerBuildOutputs, bool triggerRestoreComplete) Unknown
Microsoft.Framework.DesignTimeHost.dll!Microsoft.Framework.DesignTimeHost.ApplicationContext.DoStageOne() Unknown
Microsoft.Framework.DesignTimeHost.dll!Microsoft.Framework.DesignTimeHost.ApplicationContext.DoProcessLoop() Unknown
Microsoft.Framework.DesignTimeHost.dll!Microsoft.Framework.DesignTimeHost.ApplicationContext.ProcessLoop(object state) Unknown
mscorlib.dll!System.Threading.QueueUserWorkItemCallback.WaitCallback_Context(object state) Unknown
mscorlib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx) Unknown
mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx) Unknown
mscorlib.dll!System.Threading.QueueUserWorkItemCallback.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem() Unknown
mscorlib.dll!System.Threading.ThreadPoolWorkQueue.Dispatch() Unknown
mscorlib.dll!System.Threading._ThreadPoolWaitCallback.PerformWaitCallback() Unknown