Hello, At Tweag I/O we are considering relaxing a bit the constraints on the static form. static <exp> demands <exp> to be closed. That is, the free variables of <exp> must be bound at the top level. However, it would be fine to allow local bindings too. For instance: test :: StaticPtr ([[Int]] -> [[Int]]) test x = static (filter hasZero) where hasZero = any isZero isZero = (0 ==) Where hasZero is local but its body can be considered kind of closed (all free variables refer to top-level bindings or other *closed* local bindings.). We would need for this implementation a way to test closedness in this sense. Could there be any similar test implemented already in GHC? Thanks, Facundo [1] https://ghc.haskell.org/trac/ghc/ticket/11656