newDictsFromOld, newDicts, cloneDict,
newMethod, newMethodWithGivenTy, newMethodAtLoc,
- newOverloadedLit, newIPDict, tcInstId,
+ newOverloadedLit, newIPDict, tcInstCall,
tyVarsOfInst, tyVarsOfInsts, tyVarsOfLIE,
ipNamesOfInst, ipNamesOfInsts, predsOfInst, predsOfInsts,
lookupInst, lookupSimpleInst, LookupInstResult(..),
- isDict, isClassDict, isMethod, isLinearInst, linearInstType,
+ isDict, isClassDict, isMethod,
+ isLinearInst, linearInstType,
isTyVarDict, isStdClassTyVarDict, isMethodFor,
instBindingRequired, instCanBeGeneralised,
import CmdLineOpts ( opt_NoMethodSharing )
import HsSyn ( HsLit(..), HsOverLit(..), HsExpr(..) )
-import TcHsSyn ( TcExpr, TcId,
+import TcHsSyn ( TcExpr, TcId, TypecheckedHsExpr,
mkHsTyApp, mkHsDictApp, mkHsConApp, zonkId
)
import TcMonad
isIntTy,isFloatTy, isIntegerTy, isDoubleTy,
tcIsTyVarTy, mkPredTy, mkTyVarTy, mkTyVarTys,
tyVarsOfType, tyVarsOfTypes, tyVarsOfPred, tidyPred,
- isClassPred, isTyVarClassPred,
+ isClassPred, isTyVarClassPred, isLinearPred,
getClassPredTys, getClassPredTys_maybe, mkPredName,
tidyType, tidyTypes, tidyFreeTyVars,
tcCmpType, tcCmpTypes, tcCmpPred
-- We never build Method Insts that have
-- linear implicit paramters in them.
-- Hence no need to look for Methods
- -- See Inst.tcInstId
-
-isLinearPred :: TcPredType -> Bool
-isLinearPred (IParam (Linear n) _) = True
-isLinearPred other = False
+ -- See TcExpr.tcId
linearInstType :: Inst -> TcType -- %x::t --> t
linearInstType (Dict _ (IParam _ ty) _) = ty
%* *
%************************************************************************
-tcInstId instantiates an occurrence of an Id.
-The instantiate_it loop runs round instantiating the Id.
-It has to be a loop because we are now prepared to entertain
-types like
- f:: forall a. Eq a => forall b. Baz b => tau
-We want to instantiate this to
- f2::tau {f2 = f1 b (Baz b), f1 = f a (Eq a)}
-
-The -fno-method-sharing flag controls what happens so far as the LIE
-is concerned. The default case is that for an overloaded function we
-generate a "method" Id, and add the Method Inst to the LIE. So you get
-something like
- f :: Num a => a -> a
- f = /\a (d:Num a) -> let m = (+) a d in \ (x:a) -> m x x
-If you specify -fno-method-sharing, the dictionary application
-isn't shared, so we get
- f :: Num a => a -> a
- f = /\a (d:Num a) (x:a) -> (+) a d x x
-This gets a bit less sharing, but
- a) it's better for RULEs involving overloaded functions
- b) perhaps fewer separated lambdas
-
\begin{code}
-tcInstId :: Id -> NF_TcM (TcExpr, LIE, TcType)
-tcInstId fun
- = loop (HsVar fun) emptyLIE (idType fun)
- where
- orig = OccurrenceOf fun
- loop fun lie fun_ty = tcInstType fun_ty `thenNF_Tc` \ (tyvars, theta, tau) ->
- loop_help fun lie (mkTyVarTys tyvars) theta tau
-
- loop_help fun lie arg_tys [] tau -- Not overloaded
- = returnNF_Tc (mkHsTyApp fun arg_tys, lie, tau)
-
- loop_help (HsVar fun_id) lie arg_tys theta tau
- | can_share theta -- Sharable method binding
- = newMethodWithGivenTy orig fun_id arg_tys theta tau `thenNF_Tc` \ meth ->
- loop (HsVar (instToId meth))
- (unitLIE meth `plusLIE` lie) tau
-
- loop_help fun lie arg_tys theta tau -- The general case
- = newDicts orig theta `thenNF_Tc` \ dicts ->
- loop (mkHsDictApp (mkHsTyApp fun arg_tys) (map instToId dicts))
- (mkLIE dicts `plusLIE` lie) tau
-
- can_share theta | opt_NoMethodSharing = False
- | otherwise = not (any isLinearPred theta)
- -- This is a slight hack.
- -- If f :: (%x :: T) => Int -> Int
- -- Then if we have two separate calls, (f 3, f 4), we cannot
- -- make a method constraint that then gets shared, thus:
- -- let m = f %x in (m 3, m 4)
- -- because that loses the linearity of the constraint.
- -- The simplest thing to do is never to construct a method constraint
- -- in the first place that has a linear implicit parameter in it.
+tcInstCall :: InstOrigin -> TcType -> NF_TcM (TypecheckedHsExpr -> TypecheckedHsExpr, LIE, TcType)
+tcInstCall orig fun_ty -- fun_ty is usually a sigma-type
+ = tcInstType fun_ty `thenNF_Tc` \ (tyvars, theta, tau) ->
+ newDicts orig theta `thenNF_Tc` \ dicts ->
+ let
+ inst_fn e = mkHsDictApp (mkHsTyApp e (mkTyVarTys tyvars)) (map instToId dicts)
+ in
+ returnNF_Tc (inst_fn, mkLIE dicts, tau)
newMethod :: InstOrigin
-> TcId
import Inst ( InstOrigin(..),
LIE, mkLIE, emptyLIE, unitLIE, plusLIE, plusLIEs,
newOverloadedLit, newMethod, newIPDict,
- newDicts,
- instToId, tcInstId
+ newDicts, newMethodWithGivenTy,
+ instToId, tcInstCall
)
import TcBinds ( tcBindsAndThen )
import TcEnv ( tcLookupClass, tcLookupGlobalId, tcLookupGlobal_maybe,
import TcMonoType ( tcHsSigType, UserTypeCtxt(..) )
import TcPat ( badFieldCon )
import TcSimplify ( tcSimplifyIPs )
-import TcMType ( tcInstTyVars, newTyVarTy, newTyVarTys, zonkTcType )
+import TcMType ( tcInstTyVars, tcInstType, newHoleTyVarTy,
+ newTyVarTy, newTyVarTys, zonkTcType )
import TcType ( TcType, TcSigmaType, TcPhiType,
- tcSplitFunTys, tcSplitTyConApp,
+ tcSplitFunTys, tcSplitTyConApp, mkTyVarTys,
isSigmaTy, mkFunTy, mkAppTy, mkTyConTy,
mkTyConApp, mkClassPred, tcFunArgTy,
- tyVarsOfTypes,
+ tyVarsOfTypes, isLinearPred,
liftedTypeKind, openTypeKind, mkArrowKind,
tcSplitSigmaTy, tcTyConAppTyCon,
tidyOpenType
= tcHsSigType ExprSigCtxt poly_ty `thenTc` \ sig_tc_ty ->
tcAddErrCtxt (exprSigCtxt in_expr) $
tcExpr expr sig_tc_ty `thenTc` \ (expr', lie1) ->
- tcSub res_ty sig_tc_ty `thenTc` \ (co_fn, lie2) ->
- returnTc (co_fn <$> expr', lie1 `plusLIE` lie2)
+
+ -- Must instantiate the outer for-alls of sig_tc_ty
+ -- else we risk instantiating a ? res_ty to a forall-type
+ -- which breaks the invariant that tcMonoExpr only returns phi-types
+ tcInstCall SignatureOrigin sig_tc_ty `thenNF_Tc` \ (inst_fn, lie2, inst_sig_ty) ->
+ tcSub res_ty inst_sig_ty `thenTc` \ (co_fn, lie3) ->
+
+ returnTc (co_fn <$> inst_fn expr', lie1 `plusLIE` lie2 `plusLIE` lie3)
\end{code}
%* *
%************************************************************************
+tcId instantiates an occurrence of an Id.
+The instantiate_it loop runs round instantiating the Id.
+It has to be a loop because we are now prepared to entertain
+types like
+ f:: forall a. Eq a => forall b. Baz b => tau
+We want to instantiate this to
+ f2::tau {f2 = f1 b (Baz b), f1 = f a (Eq a)}
+
+The -fno-method-sharing flag controls what happens so far as the LIE
+is concerned. The default case is that for an overloaded function we
+generate a "method" Id, and add the Method Inst to the LIE. So you get
+something like
+ f :: Num a => a -> a
+ f = /\a (d:Num a) -> let m = (+) a d in \ (x:a) -> m x x
+If you specify -fno-method-sharing, the dictionary application
+isn't shared, so we get
+ f :: Num a => a -> a
+ f = /\a (d:Num a) (x:a) -> (+) a d x x
+This gets a bit less sharing, but
+ a) it's better for RULEs involving overloaded functions
+ b) perhaps fewer separated lambdas
+
\begin{code}
tcId :: Name -> NF_TcM (TcExpr, LIE, TcType)
tcId name -- Look up the Id and instantiate its type
= tcLookupId name `thenNF_Tc` \ id ->
- tcInstId id
+ loop (OccurrenceOf id) (HsVar id) emptyLIE (idType id)
+ where
+ loop orig (HsVar fun_id) lie fun_ty
+ | want_method_inst fun_ty
+ = tcInstType fun_ty `thenNF_Tc` \ (tyvars, theta, tau) ->
+ newMethodWithGivenTy orig fun_id
+ (mkTyVarTys tyvars) theta tau `thenNF_Tc` \ meth ->
+ loop orig (HsVar (instToId meth))
+ (unitLIE meth `plusLIE` lie) tau
+
+ loop orig fun lie fun_ty
+ | isSigmaTy fun_ty
+ = tcInstCall orig fun_ty `thenNF_Tc` \ (inst_fn, inst_lie, tau) ->
+ loop orig (inst_fn fun) (inst_lie `plusLIE` lie) tau
+
+ | otherwise
+ = returnNF_Tc (fun, lie, fun_ty)
+
+ want_method_inst fun_ty
+ | opt_NoMethodSharing = False
+ | otherwise = case tcSplitSigmaTy fun_ty of
+ (_,[],_) -> False -- Not overloaded
+ (_,theta,_) -> not (any isLinearPred theta)
+ -- This is a slight hack.
+ -- If f :: (%x :: T) => Int -> Int
+ -- Then if we have two separate calls, (f 3, f 4), we cannot
+ -- make a method constraint that then gets shared, thus:
+ -- let m = f %x in (m 3, m 4)
+ -- because that loses the linearity of the constraint.
+ -- The simplest thing to do is never to construct a method constraint
+ -- in the first place that has a linear implicit parameter in it.
\end{code}
Typecheck expression which in most cases will be an Id.
+The expression can return a higher-ranked type, such as
+ (forall a. a->a) -> Int
+so we must create a HoleTyVarTy to pass in as the expected tyvar.
\begin{code}
tcExpr_id :: RenamedHsExpr -> TcM (TcExpr, LIE, TcType)
tcExpr_id (HsVar name) = tcId name
-tcExpr_id expr = newTyVarTy openTypeKind `thenNF_Tc` \ id_ty ->
+tcExpr_id expr = newHoleTyVarTy `thenNF_Tc` \ id_ty ->
tcMonoExpr expr id_ty `thenTc` \ (expr', lie_id) ->
returnTc (expr', lie_id, id_ty)
\end{code}
import TcType ( TcTyVar, TcTyVarSet, ThetaType,
mkClassPred, isOverloadedTy, mkTyConApp,
mkTyVarTy, tcGetTyVar, isTyVarClassPred, mkTyVarTys,
- tyVarsOfPred, isIPPred, inheritablePred, predHasFDs )
+ tyVarsOfPred, isIPPred, isInheritablePred, predHasFDs )
import Id ( idType, mkUserLocal )
import Var ( TyVar )
import Name ( getOccName, getSrcLoc )
isFreeWhenInferring :: TyVarSet -> Inst -> Bool
isFreeWhenInferring qtvs inst
= isFreeWrtTyVars qtvs inst -- Constrains no quantified vars
- && all inheritablePred (predsOfInst inst) -- And no implicit parameter involved
+ && all isInheritablePred (predsOfInst inst) -- And no implicit parameter involved
-- (see "Notes on implicit parameters")
isFreeWhenChecking :: TyVarSet -- Quantified tyvars
isPredTy, isClassPred, isTyVarClassPred, predHasFDs,
mkDictTy, tcSplitPredTy_maybe, predTyUnique,
isDictTy, tcSplitDFunTy, predTyUnique,
- mkClassPred, inheritablePred, isIPPred, mkPredName,
+ mkClassPred, isInheritablePred, isLinearPred, isIPPred, mkPredName,
---------------------------------
-- Foreign import and export
import NameSet
import PrelNames -- Lots (e.g. in isFFIArgumentTy)
import TysWiredIn ( ptrTyCon, funPtrTyCon, addrTyCon, unitTyCon )
-import BasicTypes ( ipNameName )
+import BasicTypes ( IPName(..), ipNameName )
import Unique ( Unique, Uniquable(..) )
import SrcLoc ( SrcLoc )
import Util ( cmpList, thenCmp, equalLength )
isIPPred (IParam _ _) = True
isIPPred other = False
-inheritablePred :: PredType -> Bool
+isInheritablePred :: PredType -> Bool
-- Can be inherited by a context. For example, consider
-- f x = let g y = (?v, y+x)
-- in (g 3 with ?v = 8,
-- g :: (?v :: a) => a -> a
-- but it doesn't need to be quantified over the Num a dictionary
-- which can be free in g's rhs, and shared by both calls to g
-inheritablePred (ClassP _ _) = True
-inheritablePred other = False
+isInheritablePred (ClassP _ _) = True
+isInheritablePred other = False
+
+isLinearPred :: TcPredType -> Bool
+isLinearPred (IParam (Linear n) _) = True
+isLinearPred other = False
\end{code}
)
import qualified Type ( getTyVar_maybe )
import Inst ( LIE, emptyLIE, plusLIE, mkLIE,
- newDicts, instToId
+ newDicts, instToId, tcInstCall
)
import TcMType ( getTcTyVar, putTcTyVar, tcInstType,
newTyVarTy, newTyVarTys, newBoxityVar, newHoleTyVarTy,
tc_sub exp_sty expected_ty act_sty actual_ty
| isSigmaTy actual_ty
- = tcInstType actual_ty `thenNF_Tc` \ (tvs, theta, body_ty) ->
- newDicts orig theta `thenNF_Tc` \ dicts ->
- let
- inst_fn e = mkHsDictApp (mkHsTyApp e (mkTyVarTys tvs))
- (map instToId dicts)
- in
- tc_sub exp_sty expected_ty body_ty body_ty `thenTc` \ (co_fn, lie) ->
- returnTc (co_fn <.> mkCoercion inst_fn, lie `plusLIE` mkLIE dicts)
- where
- orig = Rank2Origin
+ = tcInstCall Rank2Origin actual_ty `thenNF_Tc` \ (inst_fn, lie1, body_ty) ->
+ tc_sub exp_sty expected_ty body_ty body_ty `thenTc` \ (co_fn, lie2) ->
+ returnTc (co_fn <.> mkCoercion inst_fn, lie1 `plusLIE` lie2)
-----------------------------------
-- Function case
projects / ghc-hetmet.git / commitdiff