newDictsFromOld, newDicts, cloneDict,
newMethod, newMethodWithGivenTy, newMethodAtLoc,
- newOverloadedLit, newIPDict, tcInstId,
+ newOverloadedLit, newIPDict, tcInstCall,
tyVarsOfInst, tyVarsOfInsts, tyVarsOfLIE,
ipNamesOfInst, ipNamesOfInsts, predsOfInst, predsOfInsts,
- instLoc, getDictClassTys,
+ instLoc, getDictClassTys, dictPred,
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
zonkTcThetaType, tcInstTyVar, tcInstType,
)
import TcType ( Type, TcType, TcThetaType, TcPredType, TcTauType, TcTyVarSet,
- SourceType(..), PredType, ThetaType,
+ SourceType(..), PredType, ThetaType, TyVarDetails(VanillaTv),
tcSplitForAllTys, tcSplitForAllTys,
tcSplitMethodTy, tcSplitRhoTy, 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 Id ( Id, idName, idType, mkUserLocal, mkSysLocal, mkLocalId, setIdUnique )
import PrelInfo ( isStandardClass, isCcallishClass, isNoDictClass )
import Name ( Name, mkMethodOcc, getOccName )
-import PprType ( pprPred )
+import PprType ( pprPred, pprParendType )
import Subst ( emptyInScopeSet, mkSubst,
substTy, substTyWith, substTheta, mkTyVarSubst, mkTopTyVarSubst
)
instLoc (Method _ _ _ _ _ loc) = loc
instLoc (LitInst _ _ _ loc) = loc
+dictPred (Dict _ pred _ ) = pred
+dictPred inst = pprPanic "dictPred" (ppr inst)
+
getDictClassTys (Dict _ pred _) = getClassPredTys pred
predsOfInsts :: [Inst] -> [PredType]
-- 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)
newMethod :: InstOrigin
-> TcId
tcGetUnique `thenNF_Tc` \ new_uniq ->
let
lit_inst = LitInst lit_id lit ty loc
- lit_id = mkSysLocal SLIT("lit") new_uniq ty
+ lit_id = mkSysLocal FSLIT("lit") new_uniq ty
in
returnNF_Tc (HsVar (instToId lit_inst), unitLIE lit_inst)
pprInst m@(Method u id tys theta tau loc)
= hsep [ppr id, ptext SLIT("at"),
- brackets (interppSP tys) {- ,
+ brackets (sep (map pprParendType tys)) {- ,
ptext SLIT("theta"), ppr theta,
ptext SLIT("tau"), ppr tau
show_uniq u,
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
mapNF_Tc mk_ty_arg tyvars `thenNF_Tc` \ ty_args ->
let
- subst = mkTyVarSubst tyvars ty_args
- dfun_rho = substTy subst rho
- (theta, _) = tcSplitRhoTy dfun_rho
- ty_app = mkHsTyApp (HsVar dfun_id) ty_args
+ dfun_rho = substTy (mkTyVarSubst tyvars ty_args) rho
+ (theta, _) = tcSplitRhoTy dfun_rho
+ ty_app = mkHsTyApp (HsVar dfun_id) ty_args
in
if null theta then
returnNF_Tc (SimpleInst ty_app)
projects / ghc-hetmet.git / blobdiff