anchor.diff:  let checkFbProjectsInRepo (antho : Anthology.Anthology) =
       let wsDir = Env.GetFolder Env.Folder.Workspace
       let repoWithoutProjects = antho.Repositories |> Seq.filter (fun x -> x.Builder = Anthology.BuilderType.MSBuild)
  -                                                 |> Seq.filter (fun x -> (wsDir |> IoHelpers.GetSubDirectory x.Repository.Name.toString).Exists |> not)
  +                                                 |> Seq.filter (fun x -> (wsDir |> IoHelpers.GetSubDirectory x.Repository.Name.toString).Exists)
  +                                                 |> Seq.filter (fun x -> (wsDir |> IoHelpers.GetSubDirectory x.Repository.Name.toString |> IoHelpers.GetFile ".fbprojects").Exists |> not)
                                                    |> List.ofSeq
  +
       if repoWithoutProjects <> List.empty then
           let err = repoWithoutProjects |> Seq.fold (fun s t -> sprintf "%s\n- %s" s t.Repository.Name.toString) "Found repositories without .fbprojects:"
           failwith err
  
positive.code:         failwith err
      antho
  
  let private consistencyCheck antho = 
      antho |> projectConsistencyCheck
            |> repositoryConsistencyCheck
  
  
negative.code: let checkArtifactDir (antho : Anthology.Anthology) =
      // check artifact directory
      let artifactDir = antho.Binaries |> System.IO.DirectoryInfo
      if artifactDir.Exists |> not then
          failwithf "Artifacts directory %A is not available" antho.Binaries
      antho
  
  