never executed always true always false

    1 {-# LANGUAGE TypeApplications #-}
    2 
    3 -- | COMPLETE signature
    4 module GHC.Types.CompleteMatch where
    5 
    6 import GHC.Prelude
    7 import GHC.Core.TyCo.Rep
    8 import GHC.Types.Unique.DSet
    9 import GHC.Core.ConLike
   10 import GHC.Core.TyCon
   11 import GHC.Core.Type ( splitTyConApp_maybe )
   12 import GHC.Utils.Outputable
   13 
   14 -- | A list of conlikes which represents a complete pattern match.
   15 -- These arise from @COMPLETE@ signatures.
   16 -- See also Note [Implementation of COMPLETE pragmas].
   17 data CompleteMatch = CompleteMatch
   18   { cmConLikes :: UniqDSet ConLike -- ^ The set of `ConLike` values
   19   , cmResultTyCon :: Maybe TyCon   -- ^ The optional, concrete result TyCon the set applies to
   20   }
   21 
   22 vanillaCompleteMatch :: UniqDSet ConLike -> CompleteMatch
   23 vanillaCompleteMatch cls = CompleteMatch { cmConLikes = cls, cmResultTyCon = Nothing }
   24 
   25 instance Outputable CompleteMatch where
   26   ppr (CompleteMatch cls mty) = case mty of
   27     Nothing -> ppr cls
   28     Just ty -> ppr cls <> text "@" <> parens (ppr ty)
   29 
   30 type CompleteMatches = [CompleteMatch]
   31 
   32 completeMatchAppliesAtType :: Type -> CompleteMatch -> Bool
   33 completeMatchAppliesAtType ty cm = all @Maybe ty_matches (cmResultTyCon cm)
   34   where
   35     ty_matches sig_tc
   36       | Just (tc, _arg_tys) <- splitTyConApp_maybe ty
   37       , tc == sig_tc
   38       = True
   39       | otherwise
   40       = False