Note on using the new Roslyn compiler NuGet package on Visual Studio 2015 without Update 1

If you are starting a new ASP.NET web application project in Visual Studio 2015 and you allow Visual Studio to install all recommended NuGet packages, your project will get the latest Roslyn NuGet packages. This means the default built-in CSC (C# compiler) will change to the new Roslyn compiler.

This is all great, except if you haven't yet updated your Visual Studio 2015 to Update 1. If you instead are using the RTM version, there's one drawback in using the new Roslyn compiler: the "references" feature shown above each method name will get disabled, and won't work.

To solve this, either use the traditional CSC compiler, or install Update 1 to Visual Studio. The packages related to the new Roslyn compiler are named "Microsoft.Net.Compilers" and "Microsoft.CodeDom.Providers.DotNetCompilerPlatform". This applies to .NET 4.5.x applications.