kcHsLiftedSigType, kcHsContext,
tcAddScopedTyVars, tcHsTyVars, mkImmutTyVars,
- TcSigInfo(..), tcTySig, mkTcSig, maybeSig
+ TcSigInfo(..), tcTySig, mkTcSig, maybeSig, tcSigPolyId, tcSigMonoId
) where
#include "HsVersions.h"
-import HsSyn ( HsType(..), HsTyVarBndr(..),
- Sig(..), HsPred(..), pprParendHsType, HsTupCon(..), hsTyVarNames )
+import HsSyn ( HsType(..), HsTyVarBndr(..), HsTyOp(..),
+ Sig(..), HsPred(..), HsTupCon(..), hsTyVarNames )
import RnHsSyn ( RenamedHsType, RenamedHsPred, RenamedContext, RenamedSig, extractHsTyVars )
import TcHsSyn ( TcId )
-import TcMonad
+import TcRnMonad
import TcEnv ( tcExtendTyVarEnv, tcLookup, tcLookupGlobal,
- tcInLocalScope,
- TyThing(..), TcTyThing(..), tcExtendKindEnv
+ TyThing(..), TcTyThing(..), tcExtendKindEnv,
+ getInLocalScope
)
-import TcMType ( newKindVar, zonkKindEnv, tcInstSigType,
- checkValidType, UserTypeCtxt(..), pprUserTypeCtxt
+import TcMType ( newMutTyVar, newKindVar, zonkKindEnv, tcInstType, zonkTcType,
+ checkValidType, UserTypeCtxt(..), pprUserTypeCtxt, newOpenTypeKind
)
-import TcUnify ( unifyKind, unifyOpenTypeKind )
+import TcUnify ( unifyKind, unifyFunKind )
import TcType ( Type, Kind, SourceType(..), ThetaType, TyVarDetails(..),
TcTyVar, TcKind, TcThetaType, TcTauType,
- mkTyVarTy, mkTyVarTys, mkFunTy, mkSynTy,
- hoistForAllTys, zipFunTys,
- mkSigmaTy, mkPredTy, mkTyConApp, mkAppTys,
- liftedTypeKind, unliftedTypeKind, mkArrowKind,
- mkArrowKinds, tcSplitFunTy_maybe
+ mkTyVarTy, mkTyVarTys, mkFunTy, isTypeKind,
+ zipFunTys, mkForAllTys, mkFunTys, tcEqType, isPredTy,
+ mkSigmaTy, mkPredTy, mkGenTyConApp, mkTyConApp, mkAppTys,
+ liftedTypeKind, unliftedTypeKind, eqKind,
+ tcSplitFunTy_maybe, tcSplitForAllTys
)
-import Inst ( Inst, InstOrigin(..), newMethodWithGivenTy, instToId )
+import qualified Type ( splitFunTys )
+import Inst ( Inst, InstOrigin(..), newMethod, instToId )
import Id ( mkLocalId, idName, idType )
import Var ( TyVar, mkTyVar, tyVarKind )
import ErrUtils ( Message )
-import TyCon ( TyCon, isSynTyCon, tyConKind )
+import TyCon ( TyCon, tyConKind )
import Class ( classTyCon )
import Name ( Name )
import NameSet
-import TysWiredIn ( mkListTy, mkTupleTy, genUnitTyCon )
+import Subst ( deShadowTy )
+import TysWiredIn ( mkListTy, mkPArrTy, mkTupleTy, genUnitTyCon )
import BasicTypes ( Boxity(..) )
import SrcLoc ( SrcLoc )
import Util ( lengthIs )
import Outputable
-
+import List ( nubBy )
\end{code}
\begin{code}
tcHsSigType :: UserTypeCtxt -> RenamedHsType -> TcM Type
-- Do kind checking, and hoist for-alls to the top
-tcHsSigType ctxt ty = tcAddErrCtxt (checkTypeCtxt ctxt ty) (
- kcTypeType ty `thenTc_`
+tcHsSigType ctxt ty = addErrCtxt (checkTypeCtxt ctxt ty) (
+ kcTypeType ty `thenM_`
tcHsType ty
- ) `thenTc` \ ty' ->
- checkValidType ctxt ty' `thenTc_`
- returnTc ty'
+ ) `thenM` \ ty' ->
+ checkValidType ctxt ty' `thenM_`
+ returnM ty'
checkTypeCtxt ctxt ty
= vcat [ptext SLIT("In the type:") <+> ppr ty,
-- This is used in type and class decls, where kinding is
-- done in advance, and validity checking is done later
-- [Validity checking done later because of knot-tying issues.]
-tcHsType ty = tc_type ty `thenTc` \ ty' ->
- returnTc (hoistForAllTys ty')
+tcHsType ty = tc_type ty `thenM` \ ty' ->
+ returnM (hoistForAllTys ty')
tcHsTheta :: RenamedContext -> TcM ThetaType
-- Used when we are expecting a ClassContext (i.e. no implicit params)
-- Does not do validity checking, like tcHsType
-tcHsTheta hs_theta = mapTc tc_pred hs_theta
+tcHsTheta hs_theta = mappM tc_pred hs_theta
-- In interface files the type is already kinded,
-- and we definitely don't want to hoist for-alls.
-- A useful short cut for a common case!
tcHsTyVars tv_names kind_check thing_inside
- = kcHsTyVars tv_names `thenNF_Tc` \ tv_names_w_kinds ->
- tcExtendKindEnv tv_names_w_kinds kind_check `thenTc_`
- zonkKindEnv tv_names_w_kinds `thenNF_Tc` \ tvs_w_kinds ->
+ = kcHsTyVars tv_names `thenM` \ tv_names_w_kinds ->
+ tcExtendKindEnv tv_names_w_kinds kind_check `thenM_`
+ zonkKindEnv tv_names_w_kinds `thenM` \ tvs_w_kinds ->
let
tyvars = mkImmutTyVars tvs_w_kinds
in
= thing_inside -- Quick get-out for the empty case
tcAddScopedTyVars sig_tys thing_inside
- = tcGetEnv `thenNF_Tc` \ env ->
+ = getInLocalScope `thenM` \ in_scope ->
let
all_sig_tvs = foldr (unionNameSets . extractHsTyVars) emptyNameSet sig_tys
- sig_tvs = filter not_in_scope (nameSetToList all_sig_tvs)
- not_in_scope tv = not (tcInLocalScope env tv)
+ sig_tvs = filter (not . in_scope) (nameSetToList all_sig_tvs)
in
- mapNF_Tc newNamedKindVar sig_tvs `thenTc` \ kind_env ->
- tcExtendKindEnv kind_env (kcHsSigTypes sig_tys) `thenTc_`
- zonkKindEnv kind_env `thenNF_Tc` \ tvs_w_kinds ->
- listTc [ tcNewMutTyVar name kind PatSigTv
- | (name, kind) <- tvs_w_kinds] `thenNF_Tc` \ tyvars ->
+ mappM newNamedKindVar sig_tvs `thenM` \ kind_env ->
+ tcExtendKindEnv kind_env (kcHsSigTypes sig_tys) `thenM_`
+ zonkKindEnv kind_env `thenM` \ tvs_w_kinds ->
+ sequenceM [ newMutTyVar name kind PatSigTv
+ | (name, kind) <- tvs_w_kinds] `thenM` \ tyvars ->
tcExtendTyVarEnv tyvars thing_inside
\end{code}
\begin{code}
-kcHsTyVar :: HsTyVarBndr name -> NF_TcM (name, TcKind)
-kcHsTyVars :: [HsTyVarBndr name] -> NF_TcM [(name, TcKind)]
+kcHsTyVar :: HsTyVarBndr name -> TcM (name, TcKind)
+kcHsTyVars :: [HsTyVarBndr name] -> TcM [(name, TcKind)]
kcHsTyVar (UserTyVar name) = newNamedKindVar name
-kcHsTyVar (IfaceTyVar name kind) = returnNF_Tc (name, kind)
+kcHsTyVar (IfaceTyVar name kind) = returnM (name, kind)
-kcHsTyVars tvs = mapNF_Tc kcHsTyVar tvs
+kcHsTyVars tvs = mappM kcHsTyVar tvs
-newNamedKindVar name = newKindVar `thenNF_Tc` \ kind ->
- returnNF_Tc (name, kind)
+newNamedKindVar name = newKindVar `thenM` \ kind ->
+ returnM (name, kind)
---------------------------
-kcLiftedType :: RenamedHsType -> TcM ()
+kcLiftedType :: RenamedHsType -> TcM Kind
-- The type ty must be a *lifted* *type*
-kcLiftedType ty
- = kcHsType ty `thenTc` \ kind ->
- tcAddErrCtxt (typeKindCtxt ty) $
- unifyKind liftedTypeKind kind
+kcLiftedType ty = kcHsType ty `thenM` \ act_kind ->
+ checkExpectedKind (ppr ty) act_kind liftedTypeKind
---------------------------
kcTypeType :: RenamedHsType -> TcM ()
-- The type ty must be a *type*, but it can be lifted or unlifted.
kcTypeType ty
- = kcHsType ty `thenTc` \ kind ->
- tcAddErrCtxt (typeKindCtxt ty) $
- unifyOpenTypeKind kind
+ = kcHsType ty `thenM` \ kind ->
+ if isTypeKind kind then
+ return ()
+ else
+ newOpenTypeKind `thenM` \ exp_kind ->
+ checkExpectedKind (ppr ty) kind exp_kind `thenM_`
+ returnM ()
---------------------------
kcHsSigType, kcHsLiftedSigType :: RenamedHsType -> TcM ()
-- Used for type signatures
-kcHsSigType = kcTypeType
-kcHsSigTypes tys = mapTc_ kcHsSigType tys
-kcHsLiftedSigType = kcLiftedType
+kcHsSigType ty = kcTypeType ty
+kcHsSigTypes tys = mappM_ kcHsSigType tys
+kcHsLiftedSigType ty = kcLiftedType ty `thenM_` returnM ()
---------------------------
kcHsType :: RenamedHsType -> TcM TcKind
-kcHsType (HsTyVar name) = kcTyVar name
-
-kcHsType (HsListTy ty)
- = kcLiftedType ty `thenTc` \ tau_ty ->
- returnTc liftedTypeKind
-
-kcHsType (HsTupleTy (HsTupCon _ boxity _) tys)
- = mapTc kcTypeType tys `thenTc_`
- returnTc (case boxity of
+-- kcHsType *returns* the kind of the type, rather than taking an expected
+-- kind as argument as tcExpr does. Reason: the kind of (->) is
+-- forall bx1 bx2. Type bx1 -> Type bx2 -> Type Boxed
+-- so we'd need to generate huge numbers of bx variables.
+
+kcHsType (HsTyVar name) = kcTyVar name
+kcHsType (HsListTy ty) = kcLiftedType ty
+kcHsType (HsPArrTy ty) = kcLiftedType ty
+kcHsType (HsParTy ty) = kcHsType ty -- Skip parentheses markers
+kcHsType (HsNumTy _) = returnM liftedTypeKind -- The unit type for generics
+kcHsType (HsKindSig ty k) = kcHsType ty `thenM` \ act_kind ->
+ checkExpectedKind (ppr ty) act_kind k
+
+kcHsType (HsTupleTy (HsTupCon boxity _) tys)
+ = mappM kcTypeType tys `thenM_`
+ returnM (case boxity of
Boxed -> liftedTypeKind
Unboxed -> unliftedTypeKind)
kcHsType (HsFunTy ty1 ty2)
- = kcTypeType ty1 `thenTc_`
- kcTypeType ty2 `thenTc_`
- returnTc liftedTypeKind
-
-kcHsType (HsNumTy _) -- The unit type for generics
- = returnTc liftedTypeKind
-
-kcHsType ty@(HsOpTy ty1 op ty2)
- = kcTyVar op `thenTc` \ op_kind ->
- kcHsType ty1 `thenTc` \ ty1_kind ->
- kcHsType ty2 `thenTc` \ ty2_kind ->
- tcAddErrCtxt (appKindCtxt (ppr ty)) $
- kcAppKind op_kind ty1_kind `thenTc` \ op_kind' ->
- kcAppKind op_kind' ty2_kind
-
+ = kcTypeType ty1 `thenM_`
+ kcTypeType ty2 `thenM_`
+ returnM liftedTypeKind
+
+kcHsType (HsOpTy ty1 HsArrow ty2)
+ = kcTypeType ty1 `thenM_`
+ kcTypeType ty2 `thenM_`
+ returnM liftedTypeKind
+
+kcHsType ty@(HsOpTy ty1 op_ty@(HsTyOp op) ty2)
+ = addErrCtxt (appKindCtxt (ppr ty)) $
+ kcTyVar op `thenM` \ op_kind ->
+ kcApps (ppr op_ty) op_kind [ty1,ty2]
+
kcHsType (HsPredTy pred)
- = kcHsPred pred `thenTc_`
- returnTc liftedTypeKind
+ = kcHsPred pred `thenM_`
+ returnM liftedTypeKind
kcHsType ty@(HsAppTy ty1 ty2)
- = kcHsType ty1 `thenTc` \ tc_kind ->
- kcHsType ty2 `thenTc` \ arg_kind ->
- tcAddErrCtxt (appKindCtxt (ppr ty)) $
- kcAppKind tc_kind arg_kind
+ = addErrCtxt (appKindCtxt (ppr ty)) $
+ kc_app ty []
+ where
+ kc_app (HsAppTy f a) as = kc_app f (a:as)
+ kc_app f as = kcHsType f `thenM` \ fk ->
+ kcApps (ppr f) fk as
kcHsType (HsForAllTy (Just tv_names) context ty)
- = kcHsTyVars tv_names `thenNF_Tc` \ kind_env ->
+ = kcHsTyVars tv_names `thenM` \ kind_env ->
tcExtendKindEnv kind_env $
- kcHsContext context `thenTc_`
- kcHsType ty `thenTc_`
- returnTc liftedTypeKind
+ kcHsContext context `thenM_`
+ kcLiftedType ty
+ -- The body of a forall must be of kind *
+ -- In principle, I suppose, we could allow unlifted types,
+ -- but it seems simpler to stick to lifted types for now.
---------------------------
-kcAppKind fun_kind arg_kind
- = case tcSplitFunTy_maybe fun_kind of
- Just (arg_kind', res_kind)
- -> unifyKind arg_kind arg_kind' `thenTc_`
- returnTc res_kind
+kcApps :: SDoc -- The function
+ -> TcKind -- Function kind
+ -> [RenamedHsType] -- Arg types
+ -> TcM TcKind -- Result kind
+kcApps pp_fun fun_kind args
+ = go fun_kind args
+ where
+ go fk [] = returnM fk
+ go fk (ty:tys) = unifyFunKind fk `thenM` \ mb_fk ->
+ case mb_fk of {
+ Nothing -> failWithTc too_few_args ;
+ Just (ak',fk') ->
+ kcHsType ty `thenM` \ ak ->
+ checkExpectedKind (ppr ty) ak ak' `thenM_`
+ go fk' tys }
+
+ too_few_args = ptext SLIT("Kind error:") <+> quotes pp_fun <+>
+ ptext SLIT("is applied to too many type arguments")
- Nothing -> newKindVar `thenNF_Tc` \ res_kind ->
- unifyKind fun_kind (mkArrowKind arg_kind res_kind) `thenTc_`
- returnTc res_kind
+---------------------------
+-- We would like to get a decent error message from
+-- (a) Under-applied type constructors
+-- f :: (Maybe, Maybe)
+-- (b) Over-applied type constructors
+-- f :: Int x -> Int x
+--
+checkExpectedKind :: SDoc -> TcKind -> TcKind -> TcM TcKind
+-- A fancy wrapper for 'unifyKind', which tries to give
+-- decent error messages.
+-- Returns the same kind that it is passed, exp_kind
+checkExpectedKind pp_ty act_kind exp_kind
+ | act_kind `eqKind` exp_kind -- Short cut for a very common case
+ = returnM exp_kind
+ | otherwise
+ = tryTc (unifyKind exp_kind act_kind) `thenM` \ (errs, mb_r) ->
+ case mb_r of {
+ Just _ -> returnM exp_kind ; -- Unification succeeded
+ Nothing ->
+
+ -- So there's definitely an error
+ -- Now to find out what sort
+ zonkTcType exp_kind `thenM` \ exp_kind ->
+ zonkTcType act_kind `thenM` \ act_kind ->
+
+ let (exp_as, _) = Type.splitFunTys exp_kind
+ (act_as, _) = Type.splitFunTys act_kind
+ -- Use the Type versions for kinds
+ n_exp_as = length exp_as
+ n_act_as = length act_as
+
+ err | n_exp_as < n_act_as -- E.g. [Maybe]
+ = quotes pp_ty <+> ptext SLIT("is not applied to enough type arguments")
+
+ -- Now n_exp_as >= n_act_as. In the next two cases,
+ -- n_exp_as == 0, and hence so is n_act_as
+ | exp_kind `eqKind` liftedTypeKind && act_kind `eqKind` unliftedTypeKind
+ = ptext SLIT("Expecting a lifted type, but") <+> quotes pp_ty
+ <+> ptext SLIT("is unlifted")
+
+ | exp_kind `eqKind` unliftedTypeKind && act_kind `eqKind` liftedTypeKind
+ = ptext SLIT("Expecting an unlifted type, but") <+> quotes pp_ty
+ <+> ptext SLIT("is lifted")
+
+ | otherwise -- E.g. Monad [Int]
+ = sep [ ptext SLIT("Expecting kind") <+> quotes (ppr exp_kind) <> comma,
+ ptext SLIT("but") <+> quotes pp_ty <+>
+ ptext SLIT("has kind") <+> quotes (ppr act_kind)]
+ in
+ failWithTc (ptext SLIT("Kind error:") <+> err)
+ }
---------------------------
kc_pred :: RenamedHsPred -> TcM TcKind -- Does *not* check for a saturated
= kcHsType ty
kc_pred pred@(HsClassP cls tys)
- = kcClass cls `thenTc` \ kind ->
- mapTc kcHsType tys `thenTc` \ arg_kinds ->
- newKindVar `thenNF_Tc` \ kv ->
- unifyKind kind (mkArrowKinds arg_kinds kv) `thenTc_`
- returnTc kv
+ = kcClass cls `thenM` \ kind ->
+ kcApps (ppr cls) kind tys
---------------------------
-kcHsContext ctxt = mapTc_ kcHsPred ctxt
+kcHsContext ctxt = mappM_ kcHsPred ctxt
kcHsPred pred -- Checks that the result is of kind liftedType
- = tcAddErrCtxt (appKindCtxt (ppr pred)) $
- kc_pred pred `thenTc` \ kind ->
- unifyKind liftedTypeKind kind `thenTc_`
- returnTc ()
+ = addErrCtxt (appKindCtxt (ppr pred)) $
+ kc_pred pred `thenM` \ kind ->
+ checkExpectedKind (ppr pred) kind liftedTypeKind
---------------------------
kcTyVar name -- Could be a tyvar or a tycon
- = tcLookup name `thenTc` \ thing ->
+ = tcLookup name `thenM` \ thing ->
case thing of
- AThing kind -> returnTc kind
- ATyVar tv -> returnTc (tyVarKind tv)
- AGlobal (ATyCon tc) -> returnTc (tyConKind tc)
+ AThing kind -> returnM kind
+ ATyVar tv -> returnM (tyVarKind tv)
+ AGlobal (ATyCon tc) -> returnM (tyConKind tc)
other -> failWithTc (wrongThingErr "type" thing name)
kcClass cls -- Must be a class
- = tcLookup cls `thenNF_Tc` \ thing ->
+ = tcLookup cls `thenM` \ thing ->
case thing of
- AThing kind -> returnTc kind
- AGlobal (AClass cls) -> returnTc (tyConKind (classTyCon cls))
+ AThing kind -> returnM kind
+ AGlobal (AClass cls) -> returnM (tyConKind (classTyCon cls))
other -> failWithTc (wrongThingErr "class" thing cls)
\end{code}
tc_type ty@(HsTyVar name)
= tc_app ty []
+tc_type (HsKindSig ty k)
+ = tc_type ty -- Kind checking done already
+
tc_type (HsListTy ty)
- = tc_type ty `thenTc` \ tau_ty ->
- returnTc (mkListTy tau_ty)
+ = tc_type ty `thenM` \ tau_ty ->
+ returnM (mkListTy tau_ty)
+
+tc_type (HsPArrTy ty)
+ = tc_type ty `thenM` \ tau_ty ->
+ returnM (mkPArrTy tau_ty)
-tc_type (HsTupleTy (HsTupCon _ boxity arity) tys)
+tc_type (HsTupleTy (HsTupCon boxity arity) tys)
= ASSERT( tys `lengthIs` arity )
- tc_types tys `thenTc` \ tau_tys ->
- returnTc (mkTupleTy boxity arity tau_tys)
+ tc_types tys `thenM` \ tau_tys ->
+ returnM (mkTupleTy boxity arity tau_tys)
tc_type (HsFunTy ty1 ty2)
- = tc_type ty1 `thenTc` \ tau_ty1 ->
- tc_type ty2 `thenTc` \ tau_ty2 ->
- returnTc (mkFunTy tau_ty1 tau_ty2)
+ = tc_type ty1 `thenM` \ tau_ty1 ->
+ tc_type ty2 `thenM` \ tau_ty2 ->
+ returnM (mkFunTy tau_ty1 tau_ty2)
+
+tc_type (HsOpTy ty1 HsArrow ty2)
+ = tc_type ty1 `thenM` \ tau_ty1 ->
+ tc_type ty2 `thenM` \ tau_ty2 ->
+ returnM (mkFunTy tau_ty1 tau_ty2)
+
+tc_type (HsOpTy ty1 (HsTyOp op) ty2)
+ = tc_type ty1 `thenM` \ tau_ty1 ->
+ tc_type ty2 `thenM` \ tau_ty2 ->
+ tc_fun_type op [tau_ty1,tau_ty2]
+
+tc_type (HsParTy ty) -- Remove the parentheses markers
+ = tc_type ty
tc_type (HsNumTy n)
= ASSERT(n== 1)
- returnTc (mkTyConApp genUnitTyCon [])
+ returnM (mkTyConApp genUnitTyCon [])
-tc_type (HsOpTy ty1 op ty2)
- = tc_type ty1 `thenTc` \ tau_ty1 ->
- tc_type ty2 `thenTc` \ tau_ty2 ->
- tc_fun_type op [tau_ty1,tau_ty2]
-
-tc_type (HsAppTy ty1 ty2) = tc_app ty1 [ty2]
+tc_type ty@(HsAppTy ty1 ty2)
+ = addErrCtxt (appKindCtxt (ppr ty)) $
+ tc_app ty1 [ty2]
tc_type (HsPredTy pred)
- = tc_pred pred `thenTc` \ pred' ->
- returnTc (mkPredTy pred')
+ = tc_pred pred `thenM` \ pred' ->
+ returnM (mkPredTy pred')
tc_type full_ty@(HsForAllTy (Just tv_names) ctxt ty)
= let
- kind_check = kcHsContext ctxt `thenTc_` kcHsType ty
+ kind_check = kcHsContext ctxt `thenM_` kcHsType ty
in
tcHsTyVars tv_names kind_check $ \ tyvars ->
- mapTc tc_pred ctxt `thenTc` \ theta ->
- tc_type ty `thenTc` \ tau ->
- returnTc (mkSigmaTy tyvars theta tau)
+ mappM tc_pred ctxt `thenM` \ theta ->
+ tc_type ty `thenM` \ tau ->
+ returnM (mkSigmaTy tyvars theta tau)
-tc_types arg_tys = mapTc tc_type arg_tys
+tc_types arg_tys = mappM tc_type arg_tys
\end{code}
Help functions for type applications
= tc_app ty1 (ty2:tys)
tc_app ty tys
- = tcAddErrCtxt (appKindCtxt pp_app) $
- tc_types tys `thenTc` \ arg_tys ->
+ = tc_types tys `thenM` \ arg_tys ->
case ty of
HsTyVar fun -> tc_fun_type fun arg_tys
- other -> tc_type ty `thenTc` \ fun_ty ->
- returnNF_Tc (mkAppTys fun_ty arg_tys)
- where
- pp_app = ppr ty <+> sep (map pprParendHsType tys)
+ other -> tc_type ty `thenM` \ fun_ty ->
+ returnM (mkAppTys fun_ty arg_tys)
-- (tc_fun_type ty arg_tys) returns (mkAppTys ty arg_tys)
-- But not quite; for synonyms it checks the correct arity, and builds a SynTy
-- hence the rather strange functionality.
tc_fun_type name arg_tys
- = tcLookup name `thenTc` \ thing ->
+ = tcLookup name `thenM` \ thing ->
case thing of
- ATyVar tv -> returnTc (mkAppTys (mkTyVarTy tv) arg_tys)
+ ATyVar tv -> returnM (mkAppTys (mkTyVarTy tv) arg_tys)
- AGlobal (ATyCon tc)
- | isSynTyCon tc -> returnTc (mkSynTy tc arg_tys)
- | otherwise -> returnTc (mkTyConApp tc arg_tys)
+ AGlobal (ATyCon tc) -> returnM (mkGenTyConApp tc arg_tys)
other -> failWithTc (wrongThingErr "type constructor" thing name)
\end{code}
Contexts
~~~~~~~~
\begin{code}
-tcHsPred pred = kc_pred pred `thenTc_` tc_pred pred
+tcHsPred pred = kc_pred pred `thenM_` tc_pred pred
-- Is happy with a partial application, e.g. (ST s)
-- Used from TcDeriv
tc_pred assn@(HsClassP class_name tys)
- = tcAddErrCtxt (appKindCtxt (ppr assn)) $
- tc_types tys `thenTc` \ arg_tys ->
- tcLookupGlobal class_name `thenTc` \ thing ->
+ = addErrCtxt (appKindCtxt (ppr assn)) $
+ tc_types tys `thenM` \ arg_tys ->
+ tcLookupGlobal class_name `thenM` \ thing ->
case thing of
- AClass clas -> returnTc (ClassP clas arg_tys)
+ AClass clas -> returnM (ClassP clas arg_tys)
other -> failWithTc (wrongThingErr "class" (AGlobal thing) class_name)
tc_pred assn@(HsIParam name ty)
- = tcAddErrCtxt (appKindCtxt (ppr assn)) $
- tc_type ty `thenTc` \ arg_ty ->
- returnTc (IParam name arg_ty)
+ = addErrCtxt (appKindCtxt (ppr assn)) $
+ tc_type ty `thenM` \ arg_ty ->
+ returnM (IParam name arg_ty)
\end{code}
\begin{code}
data TcSigInfo
= TySigInfo
- Name -- N, the Name in corresponding binding
-
TcId -- *Polymorphic* binder for this value...
-- Has name = N
SrcLoc -- Of the signature
instance Outputable TcSigInfo where
- ppr (TySigInfo nm id tyvars theta tau _ inst loc) =
- ppr nm <+> ptext SLIT("::") <+> ppr tyvars <+> ppr theta <+> ptext SLIT("=>") <+> ppr tau
+ ppr (TySigInfo id tyvars theta tau _ inst loc) =
+ ppr id <+> ptext SLIT("::") <+> ppr tyvars <+> ppr theta <+> ptext SLIT("=>") <+> ppr tau
+
+tcSigPolyId :: TcSigInfo -> TcId
+tcSigPolyId (TySigInfo id _ _ _ _ _ _) = id
+
+tcSigMonoId :: TcSigInfo -> TcId
+tcSigMonoId (TySigInfo _ _ _ _ id _ _) = id
maybeSig :: [TcSigInfo] -> Name -> Maybe (TcSigInfo)
-- Search for a particular signature
maybeSig [] name = Nothing
-maybeSig (sig@(TySigInfo sig_name _ _ _ _ _ _ _) : sigs) name
- | name == sig_name = Just sig
- | otherwise = maybeSig sigs name
+maybeSig (sig@(TySigInfo sig_id _ _ _ _ _ _) : sigs) name
+ | name == idName sig_id = Just sig
+ | otherwise = maybeSig sigs name
\end{code}
tcTySig :: RenamedSig -> TcM TcSigInfo
tcTySig (Sig v ty src_loc)
- = tcAddSrcLoc src_loc $
- tcHsSigType (FunSigCtxt v) ty `thenTc` \ sigma_tc_ty ->
- mkTcSig (mkLocalId v sigma_tc_ty) src_loc `thenNF_Tc` \ sig ->
- returnTc sig
+ = addSrcLoc src_loc $
+ tcHsSigType (FunSigCtxt v) ty `thenM` \ sigma_tc_ty ->
+ mkTcSig (mkLocalId v sigma_tc_ty) `thenM` \ sig ->
+ returnM sig
-mkTcSig :: TcId -> SrcLoc -> NF_TcM TcSigInfo
-mkTcSig poly_id src_loc
+mkTcSig :: TcId -> TcM TcSigInfo
+mkTcSig poly_id
= -- Instantiate this type
-- It's important to do this even though in the error-free case
-- we could just split the sigma_tc_ty (since the tyvars don't
-- the tyvars *do* get unified with something, we want to carry on
-- typechecking the rest of the program with the function bound
-- to a pristine type, namely sigma_tc_ty
- tcInstSigType SigTv (idType poly_id) `thenNF_Tc` \ (tyvars', theta', tau') ->
+ tcInstType SigTv (idType poly_id) `thenM` \ (tyvars', theta', tau') ->
- newMethodWithGivenTy SignatureOrigin
- poly_id
- (mkTyVarTys tyvars')
- theta' tau' `thenNF_Tc` \ inst ->
+ getInstLoc SignatureOrigin `thenM` \ inst_loc ->
+ newMethod inst_loc poly_id
+ (mkTyVarTys tyvars')
+ theta' tau' `thenM` \ inst ->
-- We make a Method even if it's not overloaded; no harm
+ -- But do not extend the LIE! We're just making an Id.
- returnNF_Tc (TySigInfo (idName poly_id) poly_id tyvars' theta' tau'
+ getSrcLocM `thenM` \ src_loc ->
+ returnM (TySigInfo poly_id tyvars' theta' tau'
(instToId inst) [inst] src_loc)
\end{code}
+%************************************************************************
+%* *
+\subsection{Errors and contexts}
+%* *
+%************************************************************************
+
+
+\begin{code}
+hoistForAllTys :: Type -> Type
+-- Used for user-written type signatures only
+-- Move all the foralls and constraints to the top
+-- e.g. T -> forall a. a ==> forall a. T -> a
+-- T -> (?x::Int) -> Int ==> (?x::Int) -> T -> Int
+--
+-- Also: eliminate duplicate constraints. These can show up
+-- when hoisting constraints, notably implicit parameters.
+--
+-- We want to 'look through' type synonyms when doing this
+-- so it's better done on the Type than the HsType
+
+hoistForAllTys ty
+ = let
+ no_shadow_ty = deShadowTy ty
+ -- Running over ty with an empty substitution gives it the
+ -- no-shadowing property. This is important. For example:
+ -- type Foo r = forall a. a -> r
+ -- foo :: Foo (Foo ())
+ -- Here the hoisting should give
+ -- foo :: forall a a1. a -> a1 -> ()
+ --
+ -- What about type vars that are lexically in scope in the envt?
+ -- We simply rely on them having a different unique to any
+ -- binder in 'ty'. Otherwise we'd have to slurp the in-scope-tyvars
+ -- out of the envt, which is boring and (I think) not necessary.
+ in
+ case hoist no_shadow_ty of
+ (tvs, theta, body) -> mkForAllTys tvs (mkFunTys (nubBy tcEqType theta) body)
+ -- The 'nubBy' eliminates duplicate constraints,
+ -- notably implicit parameters
+ where
+ hoist ty
+ | (tvs1, body_ty) <- tcSplitForAllTys ty,
+ not (null tvs1)
+ = case hoist body_ty of
+ (tvs2,theta,tau) -> (tvs1 ++ tvs2, theta, tau)
+
+ | Just (arg, res) <- tcSplitFunTy_maybe ty
+ = let
+ arg' = hoistForAllTys arg -- Don't forget to apply hoist recursively
+ in -- to the argument type
+ if (isPredTy arg') then
+ case hoist res of
+ (tvs,theta,tau) -> (tvs, arg':theta, tau)
+ else
+ case hoist res of
+ (tvs,theta,tau) -> (tvs, theta, mkFunTy arg' tau)
+
+ | otherwise = ([], [], ty)
+\end{code}
+
%************************************************************************
%* *
wrongThingErr expected thing name
= pp_thing thing <+> quotes (ppr name) <+> ptext SLIT("used as a") <+> text expected
where
- pp_thing (AGlobal (ATyCon _)) = ptext SLIT("Type constructor")
- pp_thing (AGlobal (AClass _)) = ptext SLIT("Class")
- pp_thing (AGlobal (AnId _)) = ptext SLIT("Identifier")
+ pp_thing (AGlobal (ATyCon _)) = ptext SLIT("Type constructor")
+ pp_thing (AGlobal (AClass _)) = ptext SLIT("Class")
+ pp_thing (AGlobal (AnId _)) = ptext SLIT("Identifier")
+ pp_thing (AGlobal (ADataCon _)) = ptext SLIT("Data constructor")
pp_thing (ATyVar _) = ptext SLIT("Type variable")
- pp_thing (ATcId _) = ptext SLIT("Local identifier")
+ pp_thing (ATcId _ _ _) = ptext SLIT("Local identifier")
pp_thing (AThing _) = ptext SLIT("Utterly bogus")
\end{code}
projects / ghc-hetmet.git / blobdiff