module Inst (
Inst,
- pprDFuns, pprDictsTheta, pprDictsInFull, -- User error messages
+ pprInstances, pprDictsTheta, pprDictsInFull, -- User error messages
showLIE, pprInst, pprInsts, pprInstInFull, -- Debugging messages
tidyInsts, tidyMoreInsts,
instLoc, getDictClassTys, dictPred,
lookupInst, LookupInstResult(..), lookupPred,
- tcExtendLocalInstEnv, tcGetInstEnvs,
+ tcExtendLocalInstEnv, tcGetInstEnvs, getOverlapFlag,
isDict, isClassDict, isMethod,
isLinearInst, linearInstType, isIPDict, isInheritableInst,
)
import TcRnMonad
import TcEnv ( tcLookupId, checkWellStaged, topIdLvl, tcMetaTy )
-import InstEnv ( DFunId, InstEnv, lookupInstEnv, checkFunDeps, extendInstEnv )
-import TcIface ( loadImportedInsts )
+import InstEnv ( DFunId, InstEnv, Instance(..), OverlapFlag(..),
+ lookupInstEnv, extendInstEnv, pprInstances,
+ instanceHead, instanceDFunId, setInstanceDFunId )
+import FunDeps ( checkFunDeps )
import TcMType ( zonkTcType, zonkTcTypes, zonkTcPredType, zonkTcThetaType,
tcInstTyVar, tcInstType, tcSkolType
)
import TcType ( Type, TcType, TcThetaType, TcTyVarSet, TcTyVar, TcPredType,
- PredType(..), SkolemInfo(..), Expected(..), typeKind, mkSigmaTy,
+ PredType(..), SkolemInfo(..), typeKind, mkSigmaTy,
tcSplitForAllTys, tcSplitForAllTys, mkFunTy,
- tcSplitPhiTy, tcIsTyVarTy, tcSplitDFunTy, tcSplitDFunHead,
+ tcSplitPhiTy, tcIsTyVarTy, tcSplitDFunHead,
isIntTy,isFloatTy, isIntegerTy, isDoubleTy,
tcIsTyVarTy, mkPredTy, mkTyVarTy, mkTyVarTys,
tyVarsOfType, tyVarsOfTypes, tyVarsOfPred, tidyPred,
getClassPredTys, getClassPredTys_maybe, mkPredName,
isInheritablePred, isIPPred,
tidyType, tidyTypes, tidyFreeTyVars, tcSplitSigmaTy,
- pprPred, pprParendType, pprThetaArrow, pprTheta, pprClassPred
+ pprPred, pprParendType, pprTheta
)
import Type ( TvSubst, substTy, substTyVar, substTyWith, substTheta, zipTopTvSubst,
notElemTvSubst, extendTvSubstList )
import BasicTypes( IPName(..), mapIPName, ipNameName )
import UniqSupply( uniqsFromSupply )
import SrcLoc ( mkSrcSpan, noLoc, unLoc, Located(..) )
-import DynFlags( DynFlags )
+import DynFlags ( DynFlag(..), dopt )
import Maybes ( isJust )
import Outputable
\end{code}
pprInstInFull inst
= sep [quotes (pprInst inst), nest 2 (pprInstLoc (instLoc inst))]
-pprDFuns :: [DFunId] -> SDoc
--- Prints the dfun as an instance declaration
-pprDFuns dfuns = vcat [ hang (ppr (getSrcLoc dfun) <> colon)
- 2 (ptext SLIT("instance") <+> sep [pprThetaArrow theta,
- pprClassPred clas tys])
- | dfun <- dfuns
- , let (_, theta, clas, tys) = tcSplitDFunTy (idType dfun) ]
- -- Print without the for-all, which the programmer doesn't write
-
tidyInst :: TidyEnv -> Inst -> Inst
tidyInst env (LitInst nm lit ty loc) = LitInst nm lit (tidyType env ty) loc
tidyInst env (Dict nm pred loc) = Dict nm (tidyPred env pred) loc
%************************************************************************
\begin{code}
-tcExtendLocalInstEnv :: [DFunId] -> TcM a -> TcM a
+tcExtendLocalInstEnv :: [Instance] -> TcM a -> TcM a
-- Add new locally-defined instances
tcExtendLocalInstEnv dfuns thing_inside
= do { traceDFuns dfuns
; env <- getGblEnv
- ; dflags <- getDOpts
- ; inst_env' <- foldlM (addInst dflags) (tcg_inst_env env) dfuns
+ ; inst_env' <- foldlM addLocalInst (tcg_inst_env env) dfuns
; let env' = env { tcg_insts = dfuns ++ tcg_insts env,
tcg_inst_env = inst_env' }
; setGblEnv env' thing_inside }
-addInst :: DynFlags -> InstEnv -> DFunId -> TcM InstEnv
+addLocalInst :: InstEnv -> Instance -> TcM InstEnv
-- Check that the proposed new instance is OK,
-- and then add it to the home inst env
-addInst dflags home_ie dfun
+addLocalInst home_ie ispec
= do { -- Instantiate the dfun type so that we extend the instance
-- envt with completely fresh template variables
-- This is important because the template variables must
-- (since we do unification).
-- We use tcSkolType because we don't want to allocate fresh
-- *meta* type variables.
- (tvs', theta', tau') <- tcSkolType (InstSkol dfun) (idType dfun)
+ let dfun = instanceDFunId ispec
+ ; (tvs', theta', tau') <- tcSkolType (InstSkol dfun) (idType dfun)
; let (cls, tys') = tcSplitDFunHead tau'
dfun' = setIdType dfun (mkSigmaTy tvs' theta' tau')
+ ispec' = setInstanceDFunId ispec dfun'
-- Load imported instances, so that we report
-- duplicates correctly
- ; pkg_ie <- loadImportedInsts cls tys'
+ ; eps <- getEps
+ ; let inst_envs = (eps_inst_env eps, home_ie)
-- Check functional dependencies
- ; case checkFunDeps (pkg_ie, home_ie) dfun' of
- Just dfuns -> funDepErr dfun dfuns
+ ; case checkFunDeps inst_envs ispec' of
+ Just specs -> funDepErr ispec' specs
Nothing -> return ()
-- Check for duplicate instance decls
- ; let { (matches, _) = lookupInstEnv dflags (pkg_ie, home_ie) cls tys'
- ; dup_dfuns = [dup_dfun | (_, (_, dup_tys, dup_dfun)) <- matches,
- isJust (tcMatchTys (mkVarSet tvs') tys' dup_tys)] }
- -- Find memebers of the match list which
- -- dfun itself matches. If the match is 2-way, it's a duplicate
- ; case dup_dfuns of
- dup_dfun : _ -> dupInstErr dfun dup_dfun
- [] -> return ()
+ ; let { (matches, _) = lookupInstEnv inst_envs cls tys'
+ ; dup_ispecs = [ dup_ispec
+ | (_, dup_ispec) <- matches
+ , let (_,_,_,dup_tys) = instanceHead dup_ispec
+ , isJust (tcMatchTys (mkVarSet tvs') tys' dup_tys)] }
+ -- Find memebers of the match list which ispec itself matches.
+ -- If the match is 2-way, it's a duplicate
+ ; case dup_ispecs of
+ dup_ispec : _ -> dupInstErr ispec' dup_ispec
+ [] -> return ()
-- OK, now extend the envt
- ; return (extendInstEnv home_ie dfun') }
-
-
-traceDFuns dfuns
- = traceTc (text "Adding instances:" <+> vcat (map pp dfuns))
+ ; return (extendInstEnv home_ie ispec') }
+
+getOverlapFlag :: TcM OverlapFlag
+getOverlapFlag
+ = do { dflags <- getDOpts
+ ; let overlap_ok = dopt Opt_AllowOverlappingInstances dflags
+ incoherent_ok = dopt Opt_AllowIncoherentInstances dflags
+ overlap_flag | incoherent_ok = Incoherent
+ | overlap_ok = OverlapOk
+ | otherwise = NoOverlap
+
+ ; return overlap_flag }
+
+traceDFuns ispecs
+ = traceTc (hang (text "Adding instances:") 2 (vcat (map pp ispecs)))
where
- pp dfun = ppr dfun <+> dcolon <+> ppr (idType dfun)
+ pp ispec = ppr (instanceDFunId ispec) <+> colon <+> ppr ispec
+ -- Print the dfun name itself too
-funDepErr dfun dfuns
- = addDictLoc dfun $
+funDepErr ispec ispecs
+ = addDictLoc ispec $
addErr (hang (ptext SLIT("Functional dependencies conflict between instance declarations:"))
- 2 (pprDFuns (dfun:dfuns)))
-dupInstErr dfun dup_dfun
- = addDictLoc dfun $
+ 2 (pprInstances (ispec:ispecs)))
+dupInstErr ispec dup_ispec
+ = addDictLoc ispec $
addErr (hang (ptext SLIT("Duplicate instance declarations:"))
- 2 (pprDFuns [dfun, dup_dfun]))
+ 2 (pprInstances [ispec, dup_ispec]))
-addDictLoc dfun thing_inside
+addDictLoc ispec thing_inside
= setSrcSpan (mkSrcSpan loc loc) thing_inside
where
- loc = getSrcLoc dfun
+ loc = getSrcLoc ispec
\end{code}
lookupPred :: TcPredType -> TcM (Maybe (TvSubst, DFunId))
-- Look up a class constraint in the instance environment
lookupPred pred@(ClassP clas tys)
- = do { pkg_ie <- loadImportedInsts clas tys
- -- Suck in any instance decls that may be relevant
+ = do { eps <- getEps
; tcg_env <- getGblEnv
- ; dflags <- getDOpts
- ; case lookupInstEnv dflags (pkg_ie, tcg_inst_env tcg_env) clas tys of {
- ([(tenv, (_,_,dfun_id))], [])
- -> do { traceTc (text "lookupInst success" <+>
+ ; let inst_envs = (eps_inst_env eps, tcg_inst_env tcg_env)
+ ; case lookupInstEnv inst_envs clas tys of {
+ ([(tenv, ispec)], [])
+ -> do { let dfun_id = is_dfun ispec
+ ; traceTc (text "lookupInst success" <+>
vcat [text "dict" <+> ppr pred,
text "witness" <+> ppr dfun_id
<+> ppr (idType dfun_id) ])
= do { dflags <- getDOpts
; let dfun_name = idName dfun_id
dfun_mod = nameModule dfun_name
- ; if isInternalName dfun_name || not (isHomeModule dflags dfun_mod)
+ ; if isInternalName dfun_name || -- Internal name => defined in this module
+ not (isHomeModule dflags dfun_mod)
then return () -- internal, or in another package
else do { tcg_env <- getGblEnv
; updMutVar (tcg_inst_uses tcg_env)
projects / ghc-hetmet.git / blobdiff