anchor.diff:                      let dep =
                           match dependencyVersionRequirement with
                           | Some installed -> installed
  -                        | None -> 
  -                            if isReferencedProject then
  -                                match version with
  -                                | Some v -> VersionRequirement.Parse (v.ToString())
  -                                | None -> VersionRequirement.AllReleases
  -                            else 
  -                                failwithf "No package with id '%A' installed in group %O." np.Name groupName
  +                        | None -> failwithf "No package with id '%A' installed in group %O." np.Name groupName
                       np.Name, dep)
           deps |> List.fold addDependency withDepsAndIncluded
  
positive.code:     | _ -> 
          let deps =
              allReferences
              |> List.filter (fun (groupName, np, isReferencedProject) ->
                  if isReferencedProject then true
                  else
                      try
                          // TODO: it would be nice if this data would be in the NuGet OData feed,
                          // then we would not need to parse every nuspec here
  
negative.code:                             not nuspec.IsDevelopmentDependency
                      with
                      | _ -> true)
              |> List.map (fun (group, np) ->
                  match group with
                  | None ->
                      match version with
                      | Some v -> np.Name,VersionRequirement.Parse (v.ToString())
                      | None -> np.Name,VersionRequirement.AllReleases
                  | Some groupName ->
                      let dependencyVersionRequirement =
                          if not lockDependencies then
                              match dependencies.Groups |> Map.tryFind groupName with
  