title: VS sees library when coding, can't find it when building
body: <p>I have an application whose main form must be injected with two repositories for a couple of databases it must use. These two repositories are both in the MyApp.Persistence project which is in the same solution, and both are in the "MyApp.Persistence" namespace. Visual Studio (ReSharper at least) knows that the reference is valid and can take me from the constructor usage to the constructor definition, and doesn't flag any errors. Object Browser also sees that MyApp.Persistence has the namespace with the same name, under which are the repositories.</p>
  
  <p>However, when the solution is built, I get a compile error that "The type or namespace name 'Persistence' does not exist in the namespace 'MyApp' (are you missing an assembly reference?)". A full rebuild doesn't solve it. Restarting VS doesn't solve it. Removing and re-adding the reference doesn't solve it. The project giving this error has plenty of other references to other solution projects which do not error. Help?</p>
  
  <p><strong>P.S.:</strong> one thing; while the IDE doesn't give an inline error on the constructor usage, it also doesn't color-code the type names blue like it normally does for a type name usage.</p>