newDictsFromOld, newDicts, cloneDict,
newMethod, newMethodWithGivenTy, newMethodAtLoc,
- newOverloadedLit, newIPDict, tcInstId,
+ newOverloadedLit, newIPDict, tcInstCall, tcInstDataCon,
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,
#include "HsVersions.h"
-import CmdLineOpts ( opt_NoMethodSharing )
import HsSyn ( HsLit(..), HsOverLit(..), HsExpr(..) )
-import TcHsSyn ( TcExpr, TcId,
+import TcHsSyn ( TcExpr, TcId, TypecheckedHsExpr,
mkHsTyApp, mkHsDictApp, mkHsConApp, zonkId
)
import TcMonad
import TcEnv ( TcIdSet, tcGetInstEnv, tcLookupId )
import InstEnv ( InstLookupResult(..), lookupInstEnv )
-import TcMType ( zonkTcType, zonkTcTypes, zonkTcPredType,
- zonkTcThetaType, tcInstTyVar, tcInstType,
+import TcMType ( zonkTcType, zonkTcTypes, zonkTcPredType, zapToType,
+ zonkTcThetaType, tcInstTyVar, tcInstType, tcInstTyVars
)
import TcType ( Type, TcType, TcThetaType, TcPredType, TcTauType, TcTyVarSet,
- SourceType(..), PredType, ThetaType,
- tcSplitForAllTys, tcSplitForAllTys,
- tcSplitMethodTy, tcSplitRhoTy, tcFunArgTy,
+ SourceType(..), PredType, ThetaType, TyVarDetails(VanillaTv),
+ tcSplitForAllTys, tcSplitForAllTys, mkTyConApp,
+ tcSplitMethodTy, tcSplitPhiTy, tcFunArgTy,
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
)
import CoreFVs ( idFreeTyVars )
import Class ( Class )
+import DataCon ( dataConSig )
import Id ( Id, idName, idType, mkUserLocal, mkSysLocal, mkLocalId, setIdUnique )
import PrelInfo ( isStandardClass, isCcallishClass, isNoDictClass )
import Name ( Name, mkMethodOcc, getOccName )
-- 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 VanillaTv 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)
+
+tcInstDataCon orig data_con
+ = let
+ (tvs, stupid_theta, ex_tvs, ex_theta, arg_tys, tycon) = dataConSig data_con
+ -- We generate constraints for the stupid theta even when
+ -- pattern matching (as the Report requires)
+ in
+ tcInstTyVars VanillaTv (ex_tvs ++ tvs) `thenNF_Tc` \ (all_tvs', ty_args', tenv) ->
+ let
+ stupid_theta' = substTheta tenv stupid_theta
+ ex_theta' = substTheta tenv ex_theta
+ arg_tys' = map (substTy tenv) arg_tys
+
+ n_ex_tvs = length ex_tvs
+ ex_tvs' = take n_ex_tvs all_tvs'
+ result_ty = mkTyConApp tycon (drop n_ex_tvs ty_args')
+ in
+ newDicts orig stupid_theta' `thenNF_Tc` \ stupid_dicts ->
+ newDicts orig ex_theta' `thenNF_Tc` \ ex_dicts ->
+
+ -- Note that we return the stupid theta *only* in the LIE;
+ -- we don't otherwise use it at all
+ returnNF_Tc (ty_args', map instToId ex_dicts, arg_tys', result_ty,
+ mkLIE stupid_dicts, mkLIE ex_dicts, ex_tvs')
+
newMethod :: InstOrigin
-> TcId
(tyvars,rho) = tcSplitForAllTys (idType real_id)
rho_ty = ASSERT( equalLength tyvars tys )
substTy (mkTopTyVarSubst tyvars tys) rho
- (theta, tau) = tcSplitRhoTy rho_ty
+ (theta, tau) = tcSplitPhiTy rho_ty
in
newMethodWith inst_loc real_id tys theta tau `thenNF_Tc` \ meth_inst ->
returnNF_Tc (meth_inst, instToId meth_inst)
-> HsOverLit
-> TcType
-> NF_TcM (TcExpr, LIE)
-newOverloadedLit orig lit ty
- | Just expr <- shortCutLit lit ty
+newOverloadedLit orig lit expected_ty
+ | Just expr <- shortCutLit lit expected_ty
= returnNF_Tc (expr, emptyLIE)
| otherwise
= tcGetInstLoc orig `thenNF_Tc` \ loc ->
tcGetUnique `thenNF_Tc` \ new_uniq ->
+ zapToType expected_ty `thenNF_Tc_`
+ -- The expected type might be a 'hole' type variable,
+ -- in which case we must zap it to an ordinary type variable
let
- lit_inst = LitInst lit_id lit ty loc
- lit_id = mkSysLocal SLIT("lit") new_uniq ty
+ lit_inst = LitInst lit_id lit expected_ty loc
+ lit_id = mkSysLocal FSLIT("lit") new_uniq expected_ty
in
returnNF_Tc (HsVar (instToId lit_inst), unitLIE lit_inst)
case lookupInstEnv dflags inst_env clas tys of
FoundInst tenv dfun_id
- -> let
+ -> -- It's possible that not all the tyvars are in
+ -- the substitution, tenv. For example:
+ -- instance C X a => D X where ...
+ -- (presumably there's a functional dependency in class C)
+ -- Hence the mk_ty_arg to instantiate any un-substituted tyvars.
+ let
(tyvars, rho) = tcSplitForAllTys (idType dfun_id)
mk_ty_arg tv = case lookupSubstEnv tenv tv of
Just (DoneTy ty) -> returnNF_Tc ty
- Nothing -> tcInstTyVar tv `thenNF_Tc` \ tc_tv ->
+ Nothing -> tcInstTyVar VanillaTv tv `thenNF_Tc` \ tc_tv ->
returnTc (mkTyVarTy tc_tv)
in
- -- It's possible that not all the tyvars are in
- -- the substitution, tenv. For example:
- -- instance C X a => D X where ...
- -- (presumably there's a functional dependency in class C)
- -- Hence the mk_ty_arg to instantiate any un-substituted tyvars.
mapNF_Tc mk_ty_arg tyvars `thenNF_Tc` \ ty_args ->
let
dfun_rho = substTy (mkTyVarSubst tyvars ty_args) rho
- (theta, _) = tcSplitRhoTy dfun_rho
+ (theta, _) = tcSplitPhiTy dfun_rho
ty_app = mkHsTyApp (HsVar dfun_id) ty_args
in
if null theta then
-> returnNF_Tc (Just (substTheta (mkSubst emptyInScopeSet tenv) theta))
where
(_, rho) = tcSplitForAllTys (idType dfun)
- (theta,_) = tcSplitRhoTy rho
+ (theta,_) = tcSplitPhiTy rho
other -> returnNF_Tc Nothing
\end{code}
projects / ghc-hetmet.git / blobdiff