mutable type variables
\begin{code}
-{-# OPTIONS -w #-}
--- The above warning supression flag is a temporary kludge.
--- While working on this module you are encouraged to remove it and fix
--- any warnings in the module. See
--- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
--- for details
-
module TcMType (
TcTyVar, TcKind, TcType, TcTauType, TcThetaType, TcTyVarSet,
zonkType, zonkTcPredType,
zonkTcTyVar, zonkTcTyVars, zonkTcTyVarsAndFV, zonkSigTyVar,
zonkQuantifiedTyVar, zonkQuantifiedTyVars,
- zonkTcType, zonkTcTypes, zonkTcClassConstraints, zonkTcThetaType,
+ zonkTcType, zonkTcTypes, zonkTcThetaType,
zonkTcKindToKind, zonkTcKind, zonkTopTyVar,
readKindVar, writeKindVar
import TcRnMonad -- TcType, amongst others
import FunDeps
import Name
+import VarEnv
import VarSet
import ErrUtils
import DynFlags
import Outputable
import FastString
-import Control.Monad ( when, unless )
+import Control.Monad
import Data.List ( (\\) )
\end{code}
}
----------------
+checkKinds :: Bool -> TyVar -> Type -> TcM ()
checkKinds swapped tv1 ty2
-- We're about to unify a type variable tv1 with a non-tyvar-type ty2.
-- ty2 has been zonked at this stage, which ensures that
-- NB the mkAppTy; we might have instantiated a
-- type variable to a type constructor, so we need
-- to pull the TyConApp to the top.
- go (ForAllTy tv ty) = notMonoType orig_ty -- (b)
+ go (ForAllTy _ _) = notMonoType orig_ty -- (b)
go (TyVarTy tv)
| orig_tv == tv = return $ Left False -- (a)
Flexi -> case box of
BoxTv -> do { ty <- fillBoxWithTau tv ref
; return $ Right ty }
- other -> return $ Right (TyVarTy tv)
+ _ -> return $ Right (TyVarTy tv)
}
-- go_syn is called for synonyms only
| not (isTauTyCon tc)
= notMonoType orig_ty -- (b) again
| otherwise
- = do { (msgs, mb_tys') <- tryTc (mapM go tys)
+ = do { (_msgs, mb_tys') <- tryTc (mapM go tys)
; case mb_tys' of
-- we had a type error => forall in type parameters
Error mesages in case of kind mismatch.
\begin{code}
+unifyKindMisMatch :: TcKind -> TcKind -> TcM ()
unifyKindMisMatch ty1 ty2 = do
ty1' <- zonkTcKind ty1
ty2' <- zonkTcKind ty2
quotes (ppr ty2')])
failWithTc msg
+unifyKindCtxt :: Bool -> TyVar -> Type -> TidyEnv -> TcM (TidyEnv, SDoc)
unifyKindCtxt swapped tv1 ty2 tidy_env -- not swapped => tv1 expected, ty2 inferred
-- tv1 and ty2 are zonked already
= return msg
do { ASSERTM2( do { details <- readMetaTyVar tyvar; return (isFlexi details) }, ppr tyvar )
; writeMutVar (metaTvRef tyvar) (Indirect ty) }
where
- k1 = tyVarKind tyvar
- k2 = typeKind ty
+ _k1 = tyVarKind tyvar
+ _k2 = typeKind ty
\end{code}
zonkTcTypes :: [TcType] -> TcM [TcType]
zonkTcTypes tys = mapM zonkTcType tys
-zonkTcClassConstraints cts = mapM zonk cts
- where zonk (clas, tys) = do
- new_tys <- zonkTcTypes tys
- return (clas, new_tys)
-
zonkTcThetaType :: TcThetaType -> TcM TcThetaType
zonkTcThetaType theta = mapM zonkTcPredType theta
actual_kind = typeKind ty
kind_ok = case ctxt of
- TySynCtxt _ -> True -- Any kind will do
- ResSigCtxt -> isSubOpenTypeKind actual_kind
- ExprSigCtxt -> isSubOpenTypeKind actual_kind
+ TySynCtxt _ -> True -- Any kind will do
+ ResSigCtxt -> isSubOpenTypeKind actual_kind
+ ExprSigCtxt -> isSubOpenTypeKind actual_kind
GenPatCtxt -> isLiftedTypeKind actual_kind
ForSigCtxt _ -> isLiftedTypeKind actual_kind
- other -> isSubArgTypeKind actual_kind
+ _ -> isSubArgTypeKind actual_kind
ubx_tup = case ctxt of
TySynCtxt _ | unboxed -> UT_Ok
-- {-# SPECIALISE instance Ord Char #-}
-- The Right Thing would be to fix the way that SPECIALISE instance pragmas
-- are handled, but the quick thing is just to permit PredTys here.
-check_type rank ubx_tup (PredTy sty)
+check_type _ _ (PredTy sty)
= do { dflags <- getDOpts
; check_pred_ty dflags TypeCtxt sty }
-check_type rank ubx_tup (TyVarTy _) = return ()
-check_type rank ubx_tup ty@(FunTy arg_ty res_ty)
+check_type _ _ (TyVarTy _) = return ()
+check_type rank _ (FunTy arg_ty res_ty)
= do { check_type (decRank rank) UT_NotOk arg_ty
; check_type rank UT_Ok res_ty }
-check_type rank ubx_tup (AppTy ty1 ty2)
+check_type rank _ (AppTy ty1 ty2)
= do { check_arg_type rank ty1
; check_arg_type rank ty2 }
= mapM_ (check_arg_type rank) tys
where
- ubx_tup_ok ub_tuples_allowed = case ubx_tup of { UT_Ok -> ub_tuples_allowed; other -> False }
+ ubx_tup_ok ub_tuples_allowed = case ubx_tup of
+ UT_Ok -> ub_tuples_allowed
+ _ -> False
n_args = length tys
tc_arity = tyConArity tc
arity_msg = arityErr "Type synonym" (tyConName tc) tc_arity n_args
ubx_tup_msg = ubxArgTyErr ty
+check_type _ _ ty = pprPanic "check_type" (ppr ty)
+
----------------------------------------
check_arg_type :: Rank -> Type -> TcM ()
-- The sort of type that can instantiate a type variable,
; checkTc (not (isUnLiftedType ty)) (unliftedArgErr ty) }
----------------------------------------
+forAllTyErr, unliftedArgErr, ubxArgTyErr :: Type -> SDoc
forAllTyErr ty = sep [ptext (sLit "Illegal polymorphic or qualified type:"), ppr ty]
unliftedArgErr ty = sep [ptext (sLit "Illegal unlifted type:"), ppr ty]
ubxArgTyErr ty = sep [ptext (sLit "Illegal unboxed tuple type as function argument:"), ppr ty]
+
+kindErr :: Kind -> SDoc
kindErr kind = sep [ptext (sLit "Expecting an ordinary type, but found a type of kind"), ppr kind]
\end{code}
| InstThetaCtxt -- Context of an instance decl
-- instance <S> => C [a] where ...
+pprSourceTyCtxt :: SourceTyCtxt -> SDoc
pprSourceTyCtxt (ClassSCCtxt c) = ptext (sLit "the super-classes of class") <+> quotes (ppr c)
pprSourceTyCtxt SigmaCtxt = ptext (sLit "the context of a polymorphic type")
pprSourceTyCtxt (DataTyCtxt tc) = ptext (sLit "the context of the data type declaration for") <+> quotes (ppr tc)
= addErrCtxt (checkThetaCtxt ctxt theta) (check_valid_theta ctxt theta)
-------------------------
-check_valid_theta ctxt []
+check_valid_theta :: SourceTyCtxt -> [PredType] -> TcM ()
+check_valid_theta _ []
= return ()
check_valid_theta ctxt theta = do
dflags <- getDOpts
arity_err = arityErr "Class" class_name arity n_tys
how_to_allow = parens (ptext (sLit "Use -XFlexibleContexts to permit this"))
-check_pred_ty dflags ctxt pred@(EqPred ty1 ty2)
+check_pred_ty dflags _ pred@(EqPred ty1 ty2)
= do { -- Equational constraints are valid in all contexts if type
-- families are permitted
; checkTc (dopt Opt_TypeFamilies dflags) (eqPredTyErr pred)
; check_mono_type ty2
}
-check_pred_ty dflags SigmaCtxt (IParam _ ty) = check_mono_type ty
+check_pred_ty _ SigmaCtxt (IParam _ ty) = check_mono_type ty
-- Implicit parameters only allowed in type
-- signatures; not in instance decls, superclasses etc
-- The reason for not allowing implicit params in instances is a bit
-- instance decl would show up two uses of ?x.
-- Catch-all
-check_pred_ty dflags ctxt sty = failWithTc (badPredTyErr sty)
+check_pred_ty _ _ sty = failWithTc (badPredTyErr sty)
-------------------------
check_class_pred_tys :: DynFlags -> SourceTyCtxt -> [Type] -> Bool
InstThetaCtxt -> flexible_contexts || undecidable_ok || all tcIsTyVarTy tys
-- Further checks on head and theta in
-- checkInstTermination
- other -> flexible_contexts || all tyvar_head tys
+ _ -> flexible_contexts || all tyvar_head tys
where
flexible_contexts = dopt Opt_FlexibleContexts dflags
undecidable_ok = dopt Opt_UndecidableInstances dflags
-------------------------
+tyvar_head :: Type -> Bool
tyvar_head ty -- Haskell 98 allows predicates of form
| tcIsTyVarTy ty = True -- C (a ty1 .. tyn)
| otherwise -- where a is a type variable
ambig_var ct_var = (ct_var `elem` forall_tyvars) &&
not (ct_var `elemVarSet` extended_tau_vars)
+ambigErr :: PredType -> SDoc
ambigErr pred
= sep [ptext (sLit "Ambiguous constraint") <+> quotes (pprPred pred),
nest 4 (ptext (sLit "At least one of the forall'd type variables mentioned by the constraint") $$
even in a scope where b is in scope.
\begin{code}
+checkFreeness :: [Var] -> [PredType] -> TcM ()
checkFreeness forall_tyvars theta
= do { flexible_contexts <- doptM Opt_FlexibleContexts
; unless flexible_contexts $ mapM_ complain (filter is_free theta) }
bound_var ct_var = ct_var `elem` forall_tyvars
complain pred = addErrTc (freeErr pred)
+freeErr :: PredType -> SDoc
freeErr pred
= sep [ ptext (sLit "All of the type variables in the constraint") <+>
quotes (pprPred pred)
\end{code}
\begin{code}
+checkThetaCtxt :: SourceTyCtxt -> ThetaType -> SDoc
checkThetaCtxt ctxt theta
= vcat [ptext (sLit "In the context:") <+> pprTheta theta,
ptext (sLit "While checking") <+> pprSourceTyCtxt ctxt ]
+badPredTyErr, eqPredTyErr, predTyVarErr :: PredType -> SDoc
badPredTyErr sty = ptext (sLit "Illegal constraint") <+> pprPred sty
eqPredTyErr sty = ptext (sLit "Illegal equational constraint") <+> pprPred sty
$$
parens (ptext (sLit "Use -XTypeFamilies to permit this"))
predTyVarErr pred = sep [ptext (sLit "Non type-variable argument"),
nest 2 (ptext (sLit "in the constraint:") <+> pprPred pred)]
+dupPredWarn :: [[PredType]] -> SDoc
dupPredWarn dups = ptext (sLit "Duplicate constraint(s):") <+> pprWithCommas pprPred (map head dups)
+arityErr :: Outputable a => String -> a -> Int -> Int -> SDoc
arityErr kind name n m
= hsep [ text kind, quotes (ppr name), ptext (sLit "should have"),
n_arguments <> comma, text "but has been given", int m]
| True = hsep [int n, ptext (sLit "arguments")]
-----------------
+notMonoType :: TcType -> TcM a
notMonoType ty
= do { ty' <- zonkTcType ty
; env0 <- tcInitTidyEnv
msg = ptext (sLit "Cannot match a monotype with") <+> quotes (ppr tidy_ty)
; failWithTcM (env1, msg) }
+notMonoArgs :: TcType -> TcM a
notMonoArgs ty
= do { ty' <- zonkTcType ty
; env0 <- tcInitTidyEnv
return (clas, tys)
}}
+check_inst_head :: DynFlags -> Class -> [Type] -> TcM ()
check_inst_head dflags clas tys
-- If GlasgowExts then check at least one isn't a type variable
= do checkTc (dopt Opt_TypeSynonymInstances dflags ||
text "Only one type can be given in an instance head." $$
text "Use -XMultiParamTypeClasses if you want to allow more.")
+instTypeErr :: SDoc -> SDoc -> SDoc
instTypeErr pp_ty msg
= sep [ptext (sLit "Illegal instance declaration for") <+> quotes pp_ty,
nest 4 msg]
| otherwise
= Nothing
+predUndecErr :: PredType -> SDoc -> SDoc
predUndecErr pred msg = sep [msg,
nest 2 (ptext (sLit "in the constraint:") <+> pprPred pred)]
+nomoreMsg, smallerMsg, undecidableMsg :: SDoc
nomoreMsg = ptext (sLit "Variable occurs more often in a constraint than in the instance head")
smallerMsg = ptext (sLit "Constraint is no smaller than the instance head")
undecidableMsg = ptext (sLit "Use -fallow-undecidable-instances to permit this")
\begin{code}
validDerivPred :: PredType -> Bool
-validDerivPred (ClassP cls tys) = hasNoDups fvs && sizeTypes tys == length fvs
- where fvs = fvTypes tys
-validDerivPred otehr = False
+validDerivPred (ClassP _ tys) = hasNoDups fvs && sizeTypes tys == length fvs
+ where fvs = fvTypes tys
+validDerivPred _ = False
\end{code}
%************************************************************************
-- Error messages
+tyFamInstInIndexErr :: Type -> SDoc
tyFamInstInIndexErr ty
= hang (ptext (sLit "Illegal type family application in type instance") <>
colon) 4 $
ppr ty
+polyTyErr :: Type -> SDoc
polyTyErr ty
= hang (ptext (sLit "Illegal polymorphic type in type instance") <> colon) 4 $
ppr ty
+famInstUndecErr :: Type -> SDoc -> SDoc
famInstUndecErr ty msg
= sep [msg,
nest 2 (ptext (sLit "in the type family application:") <+>
pprType ty)]
+nestedMsg, nomoreVarMsg, smallerAppMsg :: SDoc
nestedMsg = ptext (sLit "Nested type family application")
nomoreVarMsg = ptext (sLit "Variable occurs more often than in instance head")
smallerAppMsg = ptext (sLit "Application is no smaller than the instance head")
projects / ghc-hetmet.git / blobdiff