%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1995
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
%
\section[TcMonoType]{Typechecking user-specified @MonoTypes@}
\begin{code}
#include "HsVersions.h"
-module TcMonoType ( tcMonoType, tcInstanceType ) where
+module TcMonoType ( tcPolyType, tcMonoType, tcMonoTypeKind, tcContext ) where
-IMPORT_Trace -- ToDo: rm (debugging)
-import Outputable
-import Pretty
+import Ubiq{-uitous-}
-import TcMonad -- typechecking monad machinery
-import AbsSyn -- the stuff being typechecked
-
-#ifndef DPH
-import AbsPrel ( mkListTy, mkTupleTy, mkFunTy )
-#else
-import AbsPrel ( mkListTy, mkTupleTy, mkFunTy, mkProcessorTy, mkPodTy )
-#endif {- Data Parallel Haskell -}
-import AbsUniType ( applySynTyCon, applyNonSynTyCon, mkDictTy,
- getTyConArity, isSynTyCon, isTyVarTemplateTy,
- getUniDataTyCon_maybe, maybeUnpackFunTy
- IF_ATTACK_PRAGMAS(COMMA pprTyCon COMMA pprUniType)
- IF_ATTACK_PRAGMAS(COMMA cmpUniType)
+import HsSyn ( PolyType(..), MonoType(..), Fake )
+import RnHsSyn ( RenamedPolyType(..), RenamedMonoType(..),
+ RenamedContext(..)
)
-import UniType ( UniType(..) ) -- ******** CHEATING **** could be undone
-import TyCon --( TyCon(..) ) -- ditto, only more so
-import CE ( lookupCE, CE(..) )
-import CmdLineOpts ( GlobalSwitch(..) )
-import Errors ( confusedNameErr, tyConArityErr, instTypeErr,
- Error(..)
+
+import TcMonad
+import TcEnv ( tcLookupTyVar, tcLookupClass, tcLookupTyCon,
+ tcExtendTyVarEnv, tcTyVarScope
+ )
+import TcKind ( TcKind, mkTcTypeKind, mkBoxedTypeKind,
+ mkTcArrowKind, unifyKind, newKindVar,
+ kindToTcKind
)
-import Maybes ( Maybe(..) )
-import TcPolyType ( tcPolyType )
-import TCE ( lookupTCE, TCE(..), UniqFM )
-import TVE ( lookupTVE, TVE(..) )
-import Util
+import ErrUtils ( arityErr )
+import Type ( GenType, Type(..), ThetaType(..),
+ mkTyVarTy, mkTyConTy, mkFunTy, mkAppTy,
+ mkSigmaTy
+ )
+import TyVar ( GenTyVar, TyVar(..), mkTyVar )
+import PrelInfo ( mkListTy, mkTupleTy )
+import Type ( mkDictTy )
+import Class ( cCallishClassKeys )
+import Unique ( Unique )
+import Name ( Name(..), getNameShortName, isTyConName, getSynNameArity )
+import PprStyle
+import Pretty
+import Util ( zipWithEqual, panic )
\end{code}
+
+tcMonoType and tcMonoTypeKind
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+tcMonoType checks that the type really is of kind Type!
+
\begin{code}
-tcMonoType :: CE -> TCE -> TVE -> RenamedMonoType -> Baby_TcM UniType
-
-tcMonoType rec_ce rec_tce tve (MonoTyVar name)
- = returnB_Tc (lookupTVE tve name)
-
-tcMonoType rec_ce rec_tce tve (ListMonoTy ty)
- = tcMonoType rec_ce rec_tce tve ty `thenB_Tc` \ tau_ty ->
- returnB_Tc (mkListTy tau_ty)
-
-tcMonoType rec_ce rec_tce tve (TupleMonoTy tys)
- = mapB_Tc (tcPolyType rec_ce rec_tce tve) tys `thenB_Tc` \ tau_tys ->
- returnB_Tc (mkTupleTy (length tau_tys) tau_tys)
-
-tcMonoType rec_ce rec_tce tve (FunMonoTy ty1 ty2)
- = tcMonoType rec_ce rec_tce tve ty1 `thenB_Tc` \ tau_ty1 ->
- tcMonoType rec_ce rec_tce tve ty2 `thenB_Tc` \ tau_ty2 ->
- returnB_Tc (mkFunTy tau_ty1 tau_ty2)
-
-tcMonoType rec_ce rec_tce tve (MonoTyCon name@(WiredInTyCon tycon) tys)
- = let
- arity = getTyConArity tycon
- is_syn_tycon = isSynTyCon tycon
- in
- tcMonoType_help rec_ce rec_tce tve name tycon arity is_syn_tycon tys
-
-tcMonoType rec_ce rec_tce tve (MonoTyCon name@(PreludeTyCon _ _ arity is_data_tycon) tys)
- = tcMonoType_help rec_ce rec_tce tve name
- (lookupTCE rec_tce name)
- arity (not is_data_tycon) tys
-
-
-tcMonoType rec_ce rec_tce tve (MonoTyCon name@(OtherTyCon _ _ arity is_data_tycon _) tys)
- = tcMonoType_help rec_ce rec_tce tve name
- (lookupTCE rec_tce name)
- arity (not is_data_tycon) tys
-
-tcMonoType rec_ce rec_tce tve (MonoTyCon bad_name tys)
- = getSrcLocB_Tc `thenB_Tc` \ locn ->
- failB_Tc (confusedNameErr
- "Bad name for a type constructor (a class, or a Prelude name?)"
- bad_name locn)
-
--- two for unfoldings only:
-tcMonoType rec_ce rec_tce tve (MonoDict c ty)
- = tcMonoType rec_ce rec_tce tve ty `thenB_Tc` \ new_ty ->
- let
- clas = lookupCE rec_ce c
- in
- returnB_Tc (mkDictTy clas new_ty)
-
-tcMonoType rec_ce rec_tce tve (MonoTyVarTemplate tv_tmpl)
- = returnB_Tc (lookupTVE tve tv_tmpl)
-
-#ifdef DPH
-tcMonoType ce tce tve (MonoTyProc tys ty)
- = tcMonoTypes ce tce tve tys `thenB_Tc` \ tau_tys ->
- tcMonoType ce tce tve ty `thenB_Tc` \ tau_ty ->
- returnB_Tc (mkProcessorTy tau_tys tau_ty)
-
-tcMonoType ce tce tve (MonoTyPod ty)
- = tcMonoType ce tce tve ty `thenB_Tc` \ tau_ty ->
- returnB_Tc (mkPodTy tau_ty)
-#endif {- Data Parallel Haskell -}
-
-#ifdef DEBUG
-tcMonoType rec_ce rec_tce tve bad_ty
- = pprPanic "tcMonoType:" (ppr PprShowAll bad_ty)
-#endif
+tcMonoType :: RenamedMonoType -> TcM s Type
+
+tcMonoType ty
+ = tcMonoTypeKind ty `thenTc` \ (kind,ty) ->
+ unifyKind kind mkTcTypeKind `thenTc_`
+ returnTc ty
\end{code}
+tcMonoTypeKind does the real work. It returns a kind and a type.
+
\begin{code}
-tcMonoType_help rec_ce rec_tce tve name tycon arity is_syn_tycon tys
- = tcMonoTypes rec_ce rec_tce tve tys `thenB_Tc` \ tau_tys ->
- let cur_arity = length tys in
- getSrcLocB_Tc `thenB_Tc` \ loc ->
-
- checkB_Tc (arity /= cur_arity)
- (tyConArityErr name arity cur_arity loc) `thenB_Tc_`
-
- returnB_Tc (if is_syn_tycon then
- applySynTyCon tycon tau_tys
- else
- applyNonSynTyCon tycon tau_tys)
-
--- also not exported
-tcMonoTypes rec_ce rec_tce tve monotypes
- = mapB_Tc (tcMonoType rec_ce rec_tce tve) monotypes
+tcMonoTypeKind :: RenamedMonoType -> TcM s (TcKind s, Type)
+
+tcMonoTypeKind (MonoTyVar name)
+ = tcLookupTyVar name `thenNF_Tc` \ (kind,tyvar) ->
+ returnTc (kind, mkTyVarTy tyvar)
+
+
+tcMonoTypeKind (MonoListTy ty)
+ = tcMonoType ty `thenTc` \ tau_ty ->
+ returnTc (mkTcTypeKind, mkListTy tau_ty)
+
+tcMonoTypeKind (MonoTupleTy tys)
+ = mapTc tcMonoType tys `thenTc` \ tau_tys ->
+ returnTc (mkTcTypeKind, mkTupleTy (length tys) tau_tys)
+
+tcMonoTypeKind (MonoFunTy ty1 ty2)
+ = tcMonoType ty1 `thenTc` \ tau_ty1 ->
+ tcMonoType ty2 `thenTc` \ tau_ty2 ->
+ returnTc (mkTcTypeKind, mkFunTy tau_ty1 tau_ty2)
+
+tcMonoTypeKind (MonoTyApp name tys)
+ = mapAndUnzipTc tcMonoTypeKind tys `thenTc` \ (arg_kinds, arg_tys) ->
+
+ tc_mono_name name `thenNF_Tc` \ (fun_kind, fun_ty) ->
+
+ newKindVar `thenNF_Tc` \ result_kind ->
+ unifyKind fun_kind (foldr mkTcArrowKind result_kind arg_kinds) `thenTc_`
+
+ -- Check for saturated application in the special case of
+ -- type synoyms. Here the renamer has kindly attached the
+ -- arity to the Name.
+ synArityCheck name (length tys) `thenTc_`
+
+ returnTc (result_kind, foldl mkAppTy fun_ty arg_tys)
+
+-- for unfoldings only:
+tcMonoTypeKind (MonoForAllTy tyvars_w_kinds ty)
+ = tcExtendTyVarEnv tyvar_names (tc_kinds `zip` tyvars) (
+ tcMonoTypeKind ty `thenTc` \ (kind, ty') ->
+ unifyKind kind mkTcTypeKind `thenTc_`
+ returnTc (mkTcTypeKind, ty')
+ )
+ where
+ (tyvar_names, kinds) = unzip tyvars_w_kinds
+ tyvars = zipWithEqual mk_tyvar tyvar_names kinds
+ tc_kinds = map kindToTcKind kinds
+ mk_tyvar name kind = mkTyVar (getNameShortName name) (getItsUnique name) kind
+
+-- for unfoldings only:
+tcMonoTypeKind (MonoDictTy class_name ty)
+ = tcMonoTypeKind ty `thenTc` \ (arg_kind, arg_ty) ->
+ tcLookupClass class_name `thenNF_Tc` \ (class_kind, clas) ->
+ unifyKind class_kind arg_kind `thenTc_`
+ returnTc (mkTcTypeKind, mkDictTy clas arg_ty)
+
+
+tc_mono_name :: Name -> NF_TcM s (TcKind s, Type)
+tc_mono_name name@(Short _ _) -- Must be a type variable
+ = tcLookupTyVar name `thenNF_Tc` \ (kind,tyvar) ->
+ returnNF_Tc (kind, mkTyVarTy tyvar)
+
+tc_mono_name name | isTyConName name -- Must be a type constructor
+ = tcLookupTyCon name `thenNF_Tc` \ (kind,tycon) ->
+ returnNF_Tc (kind, mkTyConTy tycon)
+
+tc_mono_name name -- Renamer should have got it right
+ = panic ("tc_mono_name:" ++ ppShow 1000 (ppr PprDebug name))
\end{code}
-@tcInstanceType@ checks the type {\em and} its syntactic constraints:
-it must normally look like: @instance Foo (Tycon a b c ...) ...@
-(We're checking the @Tycon a b c ...@ part here...)
-The exceptions to this syntactic checking: (1)~if the @GlasgowExts@
-flag is on, or (2)~the instance is imported (they must have been
-compiled elsewhere). In these cases, we let them go through anyway.
+Contexts
+~~~~~~~~
+\begin{code}
+
+tcContext :: RenamedContext -> TcM s ThetaType
+tcContext context = mapTc tcClassAssertion context
+
+tcClassAssertion (class_name, tyvar_name)
+ = checkTc (canBeUsedInContext class_name)
+ (naughtyCCallContextErr class_name) `thenTc_`
+
+ tcLookupClass class_name `thenNF_Tc` \ (class_kind, clas) ->
+ tcLookupTyVar tyvar_name `thenNF_Tc` \ (tyvar_kind, tyvar) ->
-We can also have instances for functions: @instance Foo (a -> b) ...@.
+ unifyKind class_kind tyvar_kind `thenTc_`
+
+ returnTc (clas, mkTyVarTy tyvar)
+\end{code}
+
+HACK warning: Someone discovered that @_CCallable@ and @_CReturnable@
+could be used in contexts such as:
+\begin{verbatim}
+foo :: _CCallable a => a -> PrimIO Int
+\end{verbatim}
+
+Doing this utterly wrecks the whole point of introducing these
+classes so we specifically check that this isn't being done.
\begin{code}
-tcInstanceType :: CE -> TCE -> TVE
- -> Bool{-True <=> from this module-} -> SrcLoc
- -> RenamedMonoType
- -> Baby_TcM UniType
-
-tcInstanceType ce tce tve from_here locn mono_ty
- = tcMonoType ce tce tve mono_ty `thenB_Tc` \ tau_ty ->
- let
- (naughty, unkosher) = bad_shape tau_ty
- in
- getSwitchCheckerB_Tc `thenB_Tc` \ sw_chkr ->
- checkB_Tc
- (if not from_here || sw_chkr GlasgowExts then -- no "shape" checking
- naughty
- else
- naughty || unkosher
- )
- (instTypeErr tau_ty locn) `thenB_Tc_`
- returnB_Tc tau_ty
+canBeUsedInContext :: Name -> Bool
+canBeUsedInContext (ClassName uniq _ _) = not (uniq `elem` cCallishClassKeys)
+canBeUsedInContext other = True
+\end{code}
+
+
+Polytypes
+~~~~~~~~~
+\begin{code}
+tcPolyType :: RenamedPolyType -> TcM s Type
+tcPolyType (HsForAllTy tyvar_names context ty)
+ = tcTyVarScope tyvar_names (\ tyvars ->
+ tcContext context `thenTc` \ theta ->
+ tcMonoType ty `thenTc` \ tau ->
+ returnTc (mkSigmaTy tyvars theta tau)
+ )
+\end{code}
+
+Auxilliary functions
+~~~~~~~~~~~~~~~~~~~~
+\begin{code}
+synArityCheck :: Name -> Int -> TcM s ()
+synArityCheck name n_args
+ = case getSynNameArity name of
+ Just arity | arity /= n_args -> failTc (err arity)
+ other -> returnTc ()
where
- -- "naughty" if the type is really unacceptable, no
- -- matter what (e.g., a type synonym); "unkosher" if
- -- the Haskell report forbids it, but we allow it through
- -- under -fglasgow-exts.
-
- bad_shape ty
- = if (is_syn_type ty) then
- (True, bottom)
- else case (getUniDataTyCon_maybe ty) of
- Just (_,tys,_) -> (False, not (all isTyVarTemplateTy tys))
- Nothing -> case maybeUnpackFunTy ty of
- Just (t1, t2) -> (False,
- not (all isTyVarTemplateTy [t1, t2]))
- Nothing -> (True, bottom)
- where
- bottom = panic "bad_shape"
-
- is_syn_type ty -- ToDo: move to AbsUniType (or friend)?
- = case ty of
- UniSyn _ _ _ -> True
- _ -> False
+ err arity = arityErr "Type synonym constructor" name arity n_args
+\end{code}
+
+Errors and contexts
+~~~~~~~~~~~~~~~~~~~
+\begin{code}
+naughtyCCallContextErr clas_name sty
+ = ppSep [ppStr "Can't use class", ppr sty clas_name, ppStr "in a context"]
\end{code}
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