\begin{code}
+#include "HsVersions.h"
+
module TcType (
- TcTyVar(..),
+ SYN_IE(TcTyVar),
newTcTyVar,
newTyVarTy, -- Kind -> NF_TcM s (TcType s)
newTyVarTys, -- Int -> Kind -> NF_TcM s [TcType s]
- TcTyVarSet(..),
+ SYN_IE(TcTyVarSet),
-----------------------------------------
- TcType(..), TcMaybe(..),
- TcTauType(..), TcThetaType(..), TcRhoType(..),
+ SYN_IE(TcType), TcMaybe(..),
+ SYN_IE(TcTauType), SYN_IE(TcThetaType), SYN_IE(TcRhoType),
-- Find the type to which a type variable is bound
tcWriteTyVar, -- :: TcTyVar s -> TcType s -> NF_TcM (TcType s)
tcReadTyVar, -- :: TcTyVar s -> NF_TcM (TcMaybe s)
- tcInstTyVars, -- TyVar -> NF_TcM s (TcTyVar s)
+ tcSplitForAllTy, tcSplitRhoTy,
+
+ tcInstTyVars,
tcInstSigTyVars,
- tcInstType, tcInstTheta, tcInstId,
+ tcInstType, tcInstSigType, tcInstTcType, tcInstSigTcType,
+ tcInstTheta, tcInstId,
zonkTcTyVars,
zonkTcType,
zonkTcTypeToType,
+ zonkTcTyVar,
zonkTcTyVarToTyVar
) where
-- friends:
-import Type ( Type(..), ThetaType(..), GenType(..),
+import Type ( SYN_IE(Type), SYN_IE(ThetaType), GenType(..),
tyVarsOfTypes, getTyVar_maybe,
- splitForAllTy, splitRhoTy
+ splitForAllTy, splitRhoTy, isTyVarTy,
+ mkForAllTys, instantiateTy
)
-import TyVar ( TyVar(..), GenTyVar(..), TyVarSet(..), GenTyVarSet(..),
- TyVarEnv(..), lookupTyVarEnv, addOneToTyVarEnv, mkTyVarEnv,
+import TyVar ( SYN_IE(TyVar), GenTyVar(..), SYN_IE(TyVarSet), SYN_IE(GenTyVarSet),
+ SYN_IE(TyVarEnv), lookupTyVarEnv, addOneToTyVarEnv,
+ nullTyVarEnv, mkTyVarEnv,
tyVarSetToList
)
-- others:
-import Class ( GenClass )
-import Id ( idType )
+import Class ( GenClass, SYN_IE(Class) )
+import TyCon ( isFunTyCon )
+import Id ( idType, SYN_IE(Id) )
import Kind ( Kind )
import TcKind ( TcKind )
-import TcMonad hiding ( rnMtoTcM )
-import Usage ( Usage(..), GenUsage, UVar(..), duffUsage )
+import TcMonad
+import Usage ( SYN_IE(Usage), GenUsage, SYN_IE(UVar), duffUsage )
-import TysWiredIn ( voidTy )
+import TysPrim ( voidTy )
-import Ubiq
+IMP_Ubiq()
import Unique ( Unique )
import UniqFM ( UniqFM )
import Maybes ( assocMaybe )
-import Util ( zipEqual, nOfThem, panic, pprPanic )
-
-import Outputable ( Outputable(..) ) -- Debugging messages
-import PprType ( GenTyVar, GenType )
-import Pretty -- ditto
-import PprStyle ( PprStyle(..) ) -- ditto
+import Util ( zipEqual, nOfThem, panic{-, pprPanic, pprTrace ToDo:rm-} )
\end{code}
tcTyVarToTyVar (TyVar uniq kind name _) = TyVar uniq kind name duffUsage
\end{code}
+Utility functions
+~~~~~~~~~~~~~~~~~
+These tcSplit functions are like their non-Tc analogues, but they
+follow through bound type variables.
+
+\begin{code}
+tcSplitForAllTy :: TcType s -> NF_TcM s ([TcTyVar s], TcType s)
+tcSplitForAllTy t
+ = go t t []
+ where
+ go syn_t (ForAllTy tv t) tvs = go t t (tv:tvs)
+ go syn_t (SynTy _ _ t) tvs = go syn_t t tvs
+ go syn_t (TyVarTy tv) tvs = tcReadTyVar tv `thenNF_Tc` \ maybe_ty ->
+ case maybe_ty of
+ BoundTo ty | not (isTyVarTy ty) -> go syn_t ty tvs
+ other -> returnNF_Tc (reverse tvs, syn_t)
+ go syn_t t tvs = returnNF_Tc (reverse tvs, syn_t)
+
+tcSplitRhoTy :: TcType s -> NF_TcM s ([(Class,TcType s)], TcType s)
+tcSplitRhoTy t
+ = go t t []
+ where
+ go syn_t (FunTy (DictTy c t _) r _) ts = go r r ((c,t):ts)
+ go syn_t (AppTy (AppTy (TyConTy tycon _) (DictTy c t _)) r) ts
+ | isFunTyCon tycon
+ = go r r ((c,t):ts)
+ go syn_t (SynTy _ _ t) ts = go syn_t t ts
+ go syn_t (TyVarTy tv) ts = tcReadTyVar tv `thenNF_Tc` \ maybe_ty ->
+ case maybe_ty of
+ BoundTo ty | not (isTyVarTy ty) -> go syn_t ty ts
+ other -> returnNF_Tc (reverse ts, syn_t)
+ go syn_t t ts = returnNF_Tc (reverse ts, syn_t)
+\end{code}
+
+
Type instantiation
~~~~~~~~~~~~~~~~~~
newTyVarTys n kind = mapNF_Tc newTyVarTy (nOfThem n kind)
-
-- For signature type variables, mark them as "DontBind"
tcInstTyVars, tcInstSigTyVars
:: [GenTyVar flexi]
-> NF_TcM s ([TcTyVar s], [TcType s], [(GenTyVar flexi, TcType s)])
+
tcInstTyVars tyvars = inst_tyvars UnBound tyvars
tcInstSigTyVars tyvars = inst_tyvars DontBind tyvars
-
inst_tyvars initial_cts tyvars
= mapNF_Tc (inst_tyvar initial_cts) tyvars `thenNF_Tc` \ tc_tyvars ->
let
inst_tyvar initial_cts (TyVar _ kind name _)
= tcGetUnique `thenNF_Tc` \ uniq ->
tcNewMutVar initial_cts `thenNF_Tc` \ box ->
- returnNF_Tc (TyVar uniq kind name box)
+ returnNF_Tc (TyVar uniq kind Nothing box)
+ -- The "Nothing" means that it'll always print with its
+ -- unique (or something similar). If we leave the original (Just Name)
+ -- in there then error messages will say "can't match (T a) against (T a)"
\end{code}
-@tcInstType@ and @tcInstTcType@ both create a fresh instance of a
+@tcInstType@ and @tcInstSigType@ both create a fresh instance of a
type, returning a @TcType@. All inner for-alls are instantiated with
fresh TcTyVars.
-There are two versions, one for instantiating a @Type@, and one for a @TcType@.
-The former must instantiate everything; all tyvars must be bound either
-by a forall or by an environment passed in. The latter can do some sharing,
-and is happy with free tyvars (which is vital when instantiating the type
-of local functions). In the future @tcInstType@ may try to be clever about not
-instantiating constant sub-parts.
+The difference is that tcInstType instantiates all forall'd type
+variables (and their bindees) with UnBound type variables, whereas
+tcInstSigType instantiates them with DontBind types variables.
+@tcInstSigType@ also doesn't take an environment.
+
+On the other hand, @tcInstTcType@ instantiates a TcType. It uses
+instantiateTy which could take advantage of sharing some day.
\begin{code}
+tcInstTcType :: TcType s -> NF_TcM s ([TcTyVar s], TcType s)
+tcInstTcType ty
+ = tcSplitForAllTy ty `thenNF_Tc` \ (tyvars, rho) ->
+ case tyvars of
+ [] -> returnNF_Tc ([], ty) -- Nothing to do
+ other -> tcInstTyVars tyvars `thenNF_Tc` \ (tyvars', _, tenv) ->
+ returnNF_Tc (tyvars', instantiateTy tenv rho)
+
+tcInstSigTcType :: TcType s -> NF_TcM s ([TcTyVar s], TcType s)
+tcInstSigTcType ty
+ = tcSplitForAllTy ty `thenNF_Tc` \ (tyvars, rho) ->
+ case tyvars of
+ [] -> returnNF_Tc ([], ty) -- Nothing to do
+ other -> tcInstSigTyVars tyvars `thenNF_Tc` \ (tyvars', _, tenv) ->
+ returnNF_Tc (tyvars', instantiateTy tenv rho)
+
tcInstType :: [(GenTyVar flexi,TcType s)]
-> GenType (GenTyVar flexi) UVar
-> NF_TcM s (TcType s)
tcInstType tenv ty_to_inst
= tcConvert bind_fn occ_fn (mkTyVarEnv tenv) ty_to_inst
where
+ bind_fn = inst_tyvar UnBound
+ occ_fn env tyvar = case lookupTyVarEnv env tyvar of
+ Just ty -> returnNF_Tc ty
+ Nothing -> panic "tcInstType:1" --(vcat [ppr PprDebug ty_to_inst,
+ -- ppr PprDebug tyvar])
+
+tcInstSigType :: GenType (GenTyVar flexi) UVar -> NF_TcM s (TcType s)
+tcInstSigType ty_to_inst
+ = tcConvert bind_fn occ_fn nullTyVarEnv ty_to_inst
+ where
bind_fn = inst_tyvar DontBind
occ_fn env tyvar = case lookupTyVarEnv env tyvar of
Just ty -> returnNF_Tc ty
- Nothing -> pprPanic "tcInstType:" (ppAboves [ppr PprDebug ty_to_inst,
- ppr PprDebug tyvar])
+ Nothing -> panic "tcInstType:2"-- (vcat [ppr PprDebug ty_to_inst,
+ -- ppr PprDebug tyvar])
zonkTcTyVarToTyVar :: TcTyVar s -> NF_TcM s TyVar
-zonkTcTyVarToTyVar tyvar
- = zonkTcTyVar tyvar `thenNF_Tc` \ (TyVarTy tyvar') ->
- returnNF_Tc (tcTyVarToTyVar tyvar')
+zonkTcTyVarToTyVar tv
+ = zonkTcTyVar tv `thenNF_Tc` \ tv_ty ->
+ case tv_ty of -- Should be a tyvar!
+
+ TyVarTy tv' -> returnNF_Tc (tcTyVarToTyVar tv')
+
+ _ -> --pprTrace "zonkTcTyVarToTyVar:" (hsep [ppr PprDebug tv, ppr PprDebug tv_ty]) $
+ returnNF_Tc (tcTyVarToTyVar tv)
+
zonkTcTypeToType :: TyVarEnv Type -> TcType s -> NF_TcM s Type
zonkTcTypeToType env ty
tcConvert bind_fn occ_fn env ty_to_convert
- = do env ty_to_convert
+ = doo env ty_to_convert
where
- do env (TyConTy tycon usage) = returnNF_Tc (TyConTy tycon usage)
+ doo env (TyConTy tycon usage) = returnNF_Tc (TyConTy tycon usage)
- do env (SynTy tycon tys ty) = mapNF_Tc (do env) tys `thenNF_Tc` \ tys' ->
- do env ty `thenNF_Tc` \ ty' ->
+ doo env (SynTy tycon tys ty) = mapNF_Tc (doo env) tys `thenNF_Tc` \ tys' ->
+ doo env ty `thenNF_Tc` \ ty' ->
returnNF_Tc (SynTy tycon tys' ty')
- do env (FunTy arg res usage) = do env arg `thenNF_Tc` \ arg' ->
- do env res `thenNF_Tc` \ res' ->
+ doo env (FunTy arg res usage) = doo env arg `thenNF_Tc` \ arg' ->
+ doo env res `thenNF_Tc` \ res' ->
returnNF_Tc (FunTy arg' res' usage)
- do env (AppTy fun arg) = do env fun `thenNF_Tc` \ fun' ->
- do env arg `thenNF_Tc` \ arg' ->
+ doo env (AppTy fun arg) = doo env fun `thenNF_Tc` \ fun' ->
+ doo env arg `thenNF_Tc` \ arg' ->
returnNF_Tc (AppTy fun' arg')
- do env (DictTy clas ty usage)= do env ty `thenNF_Tc` \ ty' ->
+ doo env (DictTy clas ty usage)= doo env ty `thenNF_Tc` \ ty' ->
returnNF_Tc (DictTy clas ty' usage)
- do env (ForAllUsageTy u us ty) = do env ty `thenNF_Tc` \ ty' ->
+ doo env (ForAllUsageTy u us ty) = doo env ty `thenNF_Tc` \ ty' ->
returnNF_Tc (ForAllUsageTy u us ty')
-- The two interesting cases!
- do env (TyVarTy tv) = occ_fn env tv
+ doo env (TyVarTy tv) = occ_fn env tv
- do env (ForAllTy tyvar ty)
+ doo env (ForAllTy tyvar ty)
= bind_fn tyvar `thenNF_Tc` \ tyvar' ->
let
new_env = addOneToTyVarEnv env tyvar (TyVarTy tyvar')
in
- do new_env ty `thenNF_Tc` \ ty' ->
+ doo new_env ty `thenNF_Tc` \ ty' ->
returnNF_Tc (ForAllTy tyvar' ty')
returnNF_Tc (SynTy tc tys' ty')
zonkTcType (ForAllTy tv ty)
- = zonkTcTyVar tv `thenNF_Tc` \ (TyVarTy tv') -> -- Should be a tyvar!
+ = zonkTcTyVar tv `thenNF_Tc` \ tv_ty ->
zonkTcType ty `thenNF_Tc` \ ty' ->
- returnNF_Tc (ForAllTy tv' ty')
+ case tv_ty of -- Should be a tyvar!
+ TyVarTy tv' ->
+ returnNF_Tc (ForAllTy tv' ty')
+ _ -> --pprTrace "zonkTcType:ForAllTy:" (hsep [ppr PprDebug tv, ppr PprDebug tv_ty]) $
+
+ returnNF_Tc (ForAllTy tv{-(tcTyVarToTyVar tv)-} ty')
zonkTcType (ForAllUsageTy uv uvs ty)
= panic "zonk:ForAllUsageTy"
projects / ghc-hetmet.git / blobdiff