title: C# Dynamic Types Break When Upgrading to Visual Studio 2012
body: <p>I have a project that was originally developed using Visual Studio 2010 with .Net 4.0. It is a class library that implements a custom MVC 3 controller and it uses a <a href="http://msdn.microsoft.com/en-us/library/dd264736.aspx" rel="nofollow">dynamic type</a>. If I open the project in Visual Studio 2012 RTM, without making any changes to the project, I get the following error on the dynamic types:</p>
  
  <p><em><strong>One or more types required to compile a dynamic expression cannot be found. Are you missing a reference?</em></strong>  </p>
  
  <p>I am also getting another error, which is:</p>
  
  <p><em><strong>Missing compiler required member 'Microsoft.CSharp.RuntimeBinder.Binder.InvokeMember'</em></strong></p>
  
  <p>They seem to be related issues. I am not sure why Visual Studio 2012 is confused. The Microsoft.CSharp assembly is in the references. If I open the project again in Visual Studio 2010 it compiles just fine. Has anyone come across this issue and know a solution to it?</p>