-- | The graph of packages (nodes) and dependencies (edges) must be acyclic.
--
-- * if the result is @False@ use 'PackageIndex.dependencyCycles' to find out
--   which packages are involved in dependency cycles.
--
acyclic :: (HasUnitId ipkg,   PackageFixedDeps ipkg,
            HasUnitId srcpkg, PackageFixedDeps srcpkg)
        => PlanIndex ipkg srcpkg iresult ifailure -> Bool
acyclic = null . PlanIndex.dependencyCycles
acyclic :: (HasUnitId ipkg,   PackageFixedDeps ipkg,
            HasUnitId srcpkg, PackageFixedDeps srcpkg)
        => PlanIndex ipkg srcpkg iresult ifailure -> Bool
acyclic = null . PlanIndex.dependencyCycles
acyclic = null . PlanIndex.dependencyCycles