-- The declaration format is held in the TyCon (algTcGadtSyntax)
dcUnivTyVars :: [TyVar], -- Universally-quantified type vars
+ -- INVARIANT: length matches arity of the dcRepTyCon
+
dcExTyVars :: [TyVar], -- Existentially-quantified type vars
-- In general, the dcUnivTyVars are NOT NECESSARILY THE SAME AS THE TYVARS
-- FOR THE PARENT TyCon. With GADTs the data con might not even have
real_stricts = map mk_dict_strict_mark theta ++ arg_stricts
-- Example
- -- data instance T [a] where
- -- TI :: forall b. b -> T [Maybe b]
+ -- data instance T (b,c) where
+ -- TI :: forall e. e -> T (e,e)
+ --
-- The representation tycon looks like this:
- -- data :R7T a where
- -- TI :: forall b c. (c :=: Maybe b) b -> :R7T c
- orig_res_ty
- | Just (fam_tc, fam_tys) <- tyConFamInst_maybe tycon
- , let fam_subst = zipTopTvSubst (tyConTyVars fam_tc) res_tys
- = mkTyConApp fam_tc (substTys fam_subst fam_tys)
- | otherwise
- = mkTyConApp tycon res_tys
- where
- res_tys = substTyVars (mkTopTvSubst eq_spec) univ_tvs
- -- In the example above, res_tys is a singleton, (Maybe b)
+ -- data :R7T b c where
+ -- TI :: forall b1 c1. (b1 ~ c1) => b1 -> :R7T b1 c1
+ orig_res_ty = mkFamilyTyConApp tycon (substTyVars (mkTopTvSubst eq_spec) univ_tvs)
-- Representation arguments and demands
-- To do: eliminate duplication with MkId
dataConUserType :: DataCon -> Type
-- The user-declared type of the data constructor
-- in the nice-to-read form
--- T :: forall a. a -> T [a]
+-- T :: forall a b. a -> b -> T [a]
-- rather than
--- T :: forall b. forall a. (a=[b]) => a -> T b
+-- T :: forall a c. forall b. (c=[a]) => a -> b -> T c
-- NB: If the constructor is part of a data instance, the result type
-- mentions the family tycon, not the internal one.
dataConUserType (MkData { dcUnivTyVars = univ_tvs,
-- and for constructors visible
-> Just (tycon, ty_args, data_con, dataConInstArgTys data_con ty_args)
where
- data_con = head (tyConDataCons tycon)
+ data_con = ASSERT( not (null (tyConDataCons tycon)) )
+ head (tyConDataCons tycon)
other -> Nothing
splitProductType str ty