import HscTypes ( FixityEnv )
import Class ( className, classArity, classKey, classTyVars, classSCTheta, Class )
-import Type ( zipOpenTvSubst, substTheta, pprThetaArrow, pprClassPred )
+import Type ( zipOpenTvSubst, substTheta, pprThetaArrow, pprClassPred, mkTyVarTy )
import ErrUtils ( dumpIfSet_dyn )
import MkId ( mkDictFunId )
-import DataCon ( isNullarySrcDataCon, isVanillaDataCon, dataConOrigArgTys )
+import DataCon ( isNullarySrcDataCon, isVanillaDataCon, dataConOrigArgTys, dataConInstOrigArgTys )
import Maybes ( catMaybes )
import RdrName ( RdrName )
import Name ( Name, getSrcLoc )
import NameSet ( duDefs )
-import Kind ( splitKindFunTys )
+import Type ( splitKindFunTys )
import TyCon ( tyConTyVars, tyConDataCons, tyConArity, tyConHasGenerics,
tyConStupidTheta, isProductTyCon, isDataTyCon, newTyConRhs,
isEnumerationTyCon, isRecursiveTyCon, TyCon
)
import TcType ( TcType, ThetaType, mkTyVarTys, mkTyConApp, tcTyConAppTyCon,
isUnLiftedType, mkClassPred, tyVarsOfType,
- isArgTypeKind, tcEqTypes, tcSplitAppTys, mkAppTys )
+ isSubArgTypeKind, tcEqTypes, tcSplitAppTys, mkAppTys )
import Var ( TyVar, tyVarKind, varName )
import VarSet ( mkVarSet, subVarSet )
import PrelNames
mk_eqn_help gla_exts new_or_data tycon deriv_tvs clas tys
------------------------------------------------------------------
+ -- data/newtype T a = ... deriving( C t1 t2 )
+ -- leads to a call to mk_eqn_help with
+ -- tycon = T, deriv_tvs = ftv(t1,t2), clas = C, tys = [t1,t2]
+
mk_eqn_help gla_exts DataType tycon deriv_tvs clas tys
| Just err <- checkSideConditions gla_exts tycon deriv_tvs clas tys
= bale_out (derivingThingErr clas tys tycon (tyConTyVars tycon) err)
-- We must pass the superclasses; the newtype might be an instance
-- of them in a different way than the representation type
-- E.g. newtype Foo a = Foo a deriving( Show, Num, Eq )
- -- Then the Show instance is not done via isomprphism; it shows
+ -- Then the Show instance is not done via isomorphism; it shows
-- Foo 3 as "Foo 3"
-- The Num instance is derived via isomorphism, but the Show superclass
-- dictionary must the Show instance for Foo, *not* the Show dictionary
ordinary_constraints
= [ mkClassPred clas [arg_ty]
| data_con <- tyConDataCons tycon,
- arg_ty <- dataConOrigArgTys data_con,
+ arg_ty <- dataConInstOrigArgTys data_con (map mkTyVarTy (tyConTyVars tycon)),
not (isUnLiftedType arg_ty) -- No constraints for unlifted types?
]
-- (b) 7 or fewer args
cond_typeableOK (gla_exts, tycon)
| tyConArity tycon > 7 = Just too_many
- | not (all (isArgTypeKind . tyVarKind) (tyConTyVars tycon)) = Just bad_kind
+ | not (all (isSubArgTypeKind . tyVarKind) (tyConTyVars tycon)) = Just bad_kind
| otherwise = Nothing
where
too_many = quotes (ppr tycon) <+> ptext SLIT("has too many arguments")
\begin{code}
derivingThingErr clas tys tycon tyvars why
= sep [hsep [ptext SLIT("Can't make a derived instance of"), quotes (ppr pred)],
- parens why]
+ nest 2 (parens why)]
where
pred = mkClassPred clas (tys ++ [mkTyConApp tycon (mkTyVarTys tyvars)])