-- ** Type deconstruction
dataConRepType, dataConSig, dataConFullSig,
- dataConName, dataConIdentity, dataConTag, dataConTyCon, dataConUserType,
+ dataConName, dataConIdentity, dataConTag, dataConTyCon,
+ dataConOrigTyCon, dataConUserType,
dataConUnivTyVars, dataConExTyVars, dataConAllTyVars,
- dataConEqSpec, eqSpecPreds, dataConEqTheta, dataConDictTheta, dataConStupidTheta,
+ dataConEqSpec, eqSpecPreds, dataConEqTheta, dataConDictTheta,
+ dataConStupidTheta,
dataConInstArgTys, dataConOrigArgTys, dataConOrigResTy,
dataConInstOrigArgTys, dataConRepArgTys,
dataConFieldLabels, dataConFieldType,
import Unique
import ListSetOps
import Util
-import Maybes
import FastString
import Module
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Each data constructor C has two, and possibly up to four, Names associated with it:
- OccName Name space Name of
- ---------------------------------------------------------------------------
- * The "data con itself" C DataName DataCon
- * The "worker data con" C VarName Id (the worker)
- * The "wrapper data con" \$WC VarName Id (the wrapper)
- * The "newtype coercion" :CoT TcClsName TyCon
+ OccName Name space Name of Notes
+ ---------------------------------------------------------------------------
+ The "data con itself" C DataName DataCon In dom( GlobalRdrEnv )
+ The "worker data con" C VarName Id The worker
+ The "wrapper data con" $WC VarName Id The wrapper
+ The "newtype coercion" :CoT TcClsName TyCon
EVERY data constructor (incl for newtypes) has the former two (the
data con itself, and its worker. But only some data constructors have a
-- syntax, provided its type looks like the above.
-- The declaration format is held in the TyCon (algTcGadtSyntax)
- dcUnivTyVars :: [TyVar], -- Universally-quantified type vars
+ dcUnivTyVars :: [TyVar], -- Universally-quantified type vars [a,b,c]
-- INVARIANT: length matches arity of the dcRepTyCon
+ --- result type of (rep) data con is exactly (T a b c)
dcExTyVars :: [TyVar], -- Existentially-quantified type vars
-- In general, the dcUnivTyVars are NOT NECESSARILY THE SAME AS THE TYVARS
dataConTyCon :: DataCon -> TyCon
dataConTyCon = dcRepTyCon
+-- | The original type constructor used in the definition of this data
+-- constructor. In case of a data family instance, that will be the family
+-- type constructor.
+dataConOrigTyCon :: DataCon -> TyCon
+dataConOrigTyCon dc
+ | Just (tc, _) <- tyConFamInst_maybe (dcRepTyCon dc) = tc
+ | otherwise = dcRepTyCon dc
+
-- | The representation type of the data constructor, i.e. the sort
-- type that will represent values of this type at runtime
dataConRepType :: DataCon -> Type