allows unboxing of all previous CBV args, in which case sticking to

   VanillaIds was the only correct choice to begin with.

   Never specialised.

 Note [Specialisation Must Preserve Sharing]

       ClassOpId {}     -> False

       PrimOpId {}      -> False

       FCallId {}       -> False

       CoVarId {}       -> False

       DFunId {}        -> True

 toIfaceIdDetails nm dets@(DataConWorkId {}) = not_iface_details nm dets

 toIfaceIdDetails nm dets@(DataConWrapId {}) = not_iface_details nm dets

 toIfaceIdDetails nm dets@(FCallId {})       = not_iface_details nm dets

 toIfaceIdDetails nm dets@(CoVarId {})       = not_iface_details nm dets

 toIfaceIdDetails nm dets@(JoinId {})        = not_iface_details nm dets

       FCallId call     -> assert exactly_saturated $

                           StgOpApp (StgFCallOp call (idType f)) stg_args res_ty

       _other           -> StgApp f stg_args

   where

     -- Mostly, the arity info of a function is in the fn's IdInfo

       -- JoinId {} -> False

       --   -- Don't speculate join points

       -- -- Tagged (evaluated) ids

       -- _ | Just sig <- idTagSig_maybe i

       --   , isTaggedSig sig

         lfInfo, setLFInfo, setTagSig,

         tagSig,

     ) where

 import GHC.Prelude

 import GHC.Core.PatSyn

 import GHC.Core.ConLike

 import GHC.Types.ForeignCall

 import GHC.Types.Demand

 import GHC.Types.Cpr

 import GHC.Types.InlinePragma

   | FCallId ForeignCall         -- ^ The 'Id' is for a foreign call.

                                 -- Type will be simple: no type families, newtypes, etc

   | DFunId Bool                 -- ^ A dictionary function.

        -- Bool = True <=> a dictionary of this class cannot be bottom

        -- See Note [NON-BOTTOM-DICTS invariant] in GHC.Core

    pp (RepPolyId {})          = text "RepPolyId"

    pp (PrimOpId {})           = text "PrimOp"

    pp (FCallId _)             = text "ForeignCall"

    pp (DFunId terminating)    = text "DFunId"

                                 <> ppWhen (not terminating) (text "(may-be-bottom)")

    pp (RecSelId { sel_naughty = is_naughty })

 zapCallArityInfo :: IdInfo -> IdInfo

 zapCallArityInfo info = setCallArityInfo info 0