liquidhaskell-0.9.0.2.1: src/Language/Haskell/Liquid/Constraint/Generate.hs
{-# LANGUAGE DeriveTraversable #-}
{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE StandaloneDeriving #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE NoMonomorphismRestriction #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE TupleSections #-}
{-# LANGUAGE PatternGuards #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE ImplicitParams #-}
{-# OPTIONS_GHC -Wno-orphans #-}
-- | This module defines the representation of Subtyping and WF Constraints,
-- and the code for syntax-directed constraint generation.
module Language.Haskell.Liquid.Constraint.Generate ( generateConstraints, generateConstraintsWithEnv, caseEnv, consE ) where
import Prelude hiding (error)
import GHC.Stack
import Liquid.GHC.API as Ghc hiding ( panic
, checkErr
, (<+>)
, text
, vcat
)
import Liquid.GHC.TypeRep ()
import Text.PrettyPrint.HughesPJ hiding ((<>))
import Control.Monad.State
import Data.Functor ((<&>))
import Data.Maybe (fromMaybe, catMaybes, isJust, mapMaybe)
import qualified Data.HashMap.Strict as M
import qualified Data.HashSet as S
import qualified Data.List as L
import qualified Data.Foldable as F
import qualified Data.Traversable as T
import qualified Data.Functor.Identity
import Language.Fixpoint.Misc
import Language.Fixpoint.Types.Visitor
import qualified Language.Fixpoint.Types as F
import qualified Language.Fixpoint.Types.Visitor as F
import Language.Haskell.Liquid.Constraint.Fresh
import Language.Haskell.Liquid.Constraint.Init
import Language.Haskell.Liquid.Constraint.Env
import Language.Haskell.Liquid.Constraint.Monad
import Language.Haskell.Liquid.Constraint.Split
import Language.Haskell.Liquid.Constraint.Relational (consAssmRel, consRelTop)
import Language.Haskell.Liquid.Types.Dictionaries
import Liquid.GHC.Play (isHoleVar)
import qualified Liquid.GHC.Resugar as Rs
import qualified Liquid.GHC.SpanStack as Sp
import qualified Liquid.GHC.Misc as GM -- ( isInternal, collectArguments, tickSrcSpan, showPpr )
import Language.Haskell.Liquid.Misc
import Language.Haskell.Liquid.Constraint.Types
import Language.Haskell.Liquid.Constraint.Constraint
import Language.Haskell.Liquid.Transforms.Rec
import Language.Haskell.Liquid.Transforms.CoreToLogic (weakenResult, runToLogic, coreToLogic)
import Language.Haskell.Liquid.Bare.DataType (dataConMap, makeDataConChecker)
import Language.Haskell.Liquid.Types hiding (binds, Loc, loc, Def)
--------------------------------------------------------------------------------
-- | Constraint Generation: Toplevel -------------------------------------------
--------------------------------------------------------------------------------
generateConstraints :: TargetInfo -> CGInfo
--------------------------------------------------------------------------------
generateConstraints info = {-# SCC "ConsGen" #-} execState act $ initCGI cfg info
where
act = do { γ <- initEnv info; consAct γ cfg info }
cfg = getConfig info
generateConstraintsWithEnv :: TargetInfo -> CGInfo -> CGEnv -> CGInfo
--------------------------------------------------------------------------------
generateConstraintsWithEnv info cgi γ = {-# SCC "ConsGenEnv" #-} execState act cgi
where
act = consAct γ cfg info
cfg = getConfig info
consAct :: CGEnv -> Config -> TargetInfo -> CG ()
consAct γ cfg info = do
let sSpc = gsSig . giSpec $ info
let gSrc = giSrc info
when (gradual cfg) (mapM_ (addW . WfC γ . val . snd) (gsTySigs sSpc ++ gsAsmSigs sSpc))
γ' <- foldM (consCBTop cfg info) γ (giCbs gSrc)
-- Relational Checking: the following only runs when the list of relational specs is not empty
(ψ, γ'') <- foldM (consAssmRel cfg info) ([], γ') (gsAsmRel sSpc ++ gsRelation sSpc)
mapM_ (consRelTop cfg info γ'' ψ) (gsRelation sSpc)
-- End: Relational Checking
mapM_ (consClass γ) (gsMethods $ gsSig $ giSpec info)
hcs <- gets hsCs
hws <- gets hsWfs
fcs <- concat <$> mapM (splitC (typeclass (getConfig info))) hcs
fws <- concat <$> mapM splitW hws
modify $ \st -> st { fEnv = fEnv st `mappend` feEnv (fenv γ)
, cgLits = litEnv γ
, cgConsts = cgConsts st `mappend` constEnv γ
, fixCs = fcs
, fixWfs = fws }
--------------------------------------------------------------------------------
-- | Ensure that the instance type is a subtype of the class type --------------
--------------------------------------------------------------------------------
consClass :: CGEnv -> (Var, MethodType LocSpecType) -> CG ()
consClass γ (x,mt)
| Just ti <- tyInstance mt
, Just tc <- tyClass mt
= addC (SubC (γ `setLocation` Sp.Span (GM.fSrcSpan (F.loc ti))) (val ti) (val tc)) ("cconsClass for " ++ GM.showPpr x)
consClass _ _
= return ()
--------------------------------------------------------------------------------
-- | TERMINATION TYPE ----------------------------------------------------------
--------------------------------------------------------------------------------
makeDecrIndex :: (Var, Template SpecType, [Var]) -> CG [Int]
makeDecrIndex (x, Assumed t, args)
= do dindex <- makeDecrIndexTy x t args
case dindex of
Left msg -> addWarning msg >> return []
Right i -> return i
makeDecrIndex (x, Asserted t, args)
= do dindex <- makeDecrIndexTy x t args
case dindex of
Left msg -> addWarning msg >> return []
Right i -> return i
makeDecrIndex _ = return []
makeDecrIndexTy :: Var -> SpecType -> [Var] -> CG (Either (TError t) [Int])
makeDecrIndexTy x st args
= do spDecr <- gets specDecr
autosz <- gets autoSize
hint <- checkHint' autosz (L.lookup x spDecr)
case dindex autosz of
Nothing -> return $ Left msg
Just i -> return $ Right $ fromMaybe [i] hint
where
ts = ty_args trep
tvs = zip ts args
msg = ErrTermin (getSrcSpan x) [F.pprint x] (text "No decreasing parameter")
cenv = makeNumEnv ts
trep = toRTypeRep $ unOCons st
p autosz (t, v) = isDecreasing autosz cenv t && not (isIdTRecBound v)
checkHint' autosz = checkHint x ts (isDecreasing autosz cenv)
dindex autosz = L.findIndex (p autosz) tvs
recType :: F.Symbolic a
=> S.HashSet TyCon
-> (([a], [Int]), (t, [Int], SpecType))
-> SpecType
recType _ ((_, []), (_, [], t))
= t
recType autoenv ((vs, indexc), (_, index, t))
= makeRecType autoenv t v dxt index
where v = (vs !!) <$> indexc
dxt = (xts !!) <$> index
xts = zip (ty_binds trep) (ty_args trep)
trep = toRTypeRep $ unOCons t
checkIndex :: (NamedThing t, PPrint t, PPrint a)
=> (t, [a], Template (RType c tv r), [Int])
-> CG [Maybe (RType c tv r)]
checkIndex (x, vs, t, index)
= do mapM_ (safeLogIndex msg1 vs) index
mapM (safeLogIndex msg2 ts) index
where
loc = getSrcSpan x
ts = ty_args $ toRTypeRep $ unOCons $ unTemplate t
msg1 = ErrTermin loc [xd] ("No decreasing" <+> F.pprint index <-> "-th argument on" <+> xd <+> "with" <+> F.pprint vs)
msg2 = ErrTermin loc [xd] "No decreasing parameter"
xd = F.pprint x
makeRecType :: (Enum a1, Eq a1, Num a1, F.Symbolic a)
=> S.HashSet TyCon
-> SpecType
-> [a]
-> [(F.Symbol, SpecType)]
-> [a1]
-> SpecType
makeRecType autoenv t vs dxs is
= mergecondition t $ fromRTypeRep $ trep {ty_binds = xs', ty_args = ts'}
where
(xs', ts') = unzip $ replaceN (last is) (safeFromLeft "makeRecType" $ makeDecrType autoenv vdxs) xts
vdxs = zip vs dxs
xts = zip (ty_binds trep) (ty_args trep)
trep = toRTypeRep $ unOCons t
unOCons :: RType c tv r -> RType c tv r
unOCons (RAllT v t r) = RAllT v (unOCons t) r
unOCons (RAllP p t) = RAllP p $ unOCons t
unOCons (RFun x i tx t r) = RFun x i (unOCons tx) (unOCons t) r
unOCons (RRTy _ _ OCons t) = unOCons t
unOCons t = t
mergecondition :: RType c tv r -> RType c tv r -> RType c tv r
mergecondition (RAllT _ t1 _) (RAllT v t2 r2) = RAllT v (mergecondition t1 t2) r2
mergecondition (RAllP _ t1) (RAllP p t2) = RAllP p (mergecondition t1 t2)
mergecondition (RRTy xts r OCons t1) t2 = RRTy xts r OCons (mergecondition t1 t2)
mergecondition (RFun _ _ t11 t12 _) (RFun x2 i t21 t22 r2) = RFun x2 i (mergecondition t11 t21) (mergecondition t12 t22) r2
mergecondition _ t = t
safeLogIndex :: Error -> [a] -> Int -> CG (Maybe a)
safeLogIndex err ls n
| n >= length ls = addWarning err >> return Nothing
| otherwise = return $ Just $ ls !! n
checkHint :: (NamedThing a, PPrint a, PPrint a1)
=> a -> [a1] -> (a1 -> Bool) -> Maybe [Int] -> CG (Maybe [Int])
checkHint _ _ _ Nothing
= return Nothing
checkHint x _ _ (Just ns) | L.sort ns /= ns
= addWarning (ErrTermin loc [dx] (text "The hints should be increasing")) >> return Nothing
where
loc = getSrcSpan x
dx = F.pprint x
checkHint x ts f (Just ns)
= mapM (checkValidHint x ts f) ns <&> (Just . catMaybes)
checkValidHint :: (NamedThing a, PPrint a, PPrint a1)
=> a -> [a1] -> (a1 -> Bool) -> Int -> CG (Maybe Int)
checkValidHint x ts f n
| n < 0 || n >= length ts = addWarning err >> return Nothing
| f (ts L.!! n) = return $ Just n
| otherwise = addWarning err >> return Nothing
where
err = ErrTermin loc [xd] (vcat [ "Invalid Hint" <+> F.pprint (n+1) <+> "for" <+> xd
, "in"
, F.pprint ts ])
loc = getSrcSpan x
xd = F.pprint x
--------------------------------------------------------------------------------
consCBLet :: CGEnv -> CoreBind -> CG CGEnv
--------------------------------------------------------------------------------
consCBLet γ cb = do
oldtcheck <- gets tcheck
isStr <- doTermCheck (getConfig γ) cb
-- TODO: yuck.
modify $ \s -> s { tcheck = oldtcheck && isStr }
γ' <- consCB (oldtcheck && isStr) isStr γ cb
modify $ \s -> s{tcheck = oldtcheck}
return γ'
--------------------------------------------------------------------------------
-- | Constraint Generation: Corebind -------------------------------------------
--------------------------------------------------------------------------------
consCBTop :: Config -> TargetInfo -> CGEnv -> CoreBind -> CG CGEnv
--------------------------------------------------------------------------------
consCBTop cfg info cgenv cb
| all (trustVar cfg info) xs
= foldM addB cgenv xs
where
xs = bindersOf cb
tt = trueTy (typeclass cfg) . varType
addB γ x = tt x >>= (\t -> γ += ("derived", F.symbol x, t))
consCBTop _ _ γ cb
= do oldtcheck <- gets tcheck
-- lazyVars <- specLazy <$> get
isStr <- doTermCheck (getConfig γ) cb
modify $ \s -> s { tcheck = oldtcheck && isStr}
-- remove invariants that came from the cb definition
let (γ', i) = removeInvariant γ cb --- DIFF
γ'' <- consCB (oldtcheck && isStr) isStr (γ'{cgVar = topBind cb}) cb
modify $ \s -> s { tcheck = oldtcheck}
return $ restoreInvariant γ'' i --- DIFF
where
topBind (NonRec v _) = Just v
topBind (Rec [(v,_)]) = Just v
topBind _ = Nothing
trustVar :: Config -> TargetInfo -> Var -> Bool
trustVar cfg info x = not (checkDerived cfg) && derivedVar (giSrc info) x
derivedVar :: TargetSrc -> Var -> Bool
derivedVar src x = S.member x (giDerVars src)
doTermCheck :: Config -> Bind Var -> CG Bool
doTermCheck cfg bind = do
lazyVs <- gets specLazy
termVs <- gets specTmVars
let skip = any (\x -> S.member x lazyVs || nocheck x) xs
let chk = not (structuralTerm cfg) || any (`S.member` termVs) xs
return $ chk && not skip
where
nocheck = if typeclass cfg then GM.isEmbeddedDictVar else GM.isInternal
xs = bindersOf bind
-- nonStructTerm && not skip
-- RJ: AAAAAAARGHHH!!!!!! THIS CODE IS HORRIBLE!!!!!!!!!
consCBSizedTys :: CGEnv -> [(Var, CoreExpr)] -> CG CGEnv
consCBSizedTys γ xes
= do xets <- forM xes $ \(x, e) -> fmap (x, e,) (varTemplate γ (x, Just e))
autoenv <- gets autoSize
ts <- mapM (T.mapM refreshArgs) (thd3 <$> xets)
let vs = zipWith collectArgs' ts es
is <- mapM makeDecrIndex (zip3 vars ts vs) >>= checkSameLens
let xeets = (\vis -> [(vis, x) | x <- zip3 vars is $ map unTemplate ts]) <$> zip vs is
_ <- mapM checkIndex (zip4 vars vs ts is) >>= checkEqTypes . L.transpose
let rts = (recType autoenv <$>) <$> xeets
let xts = zip vars ts
γ' <- foldM extender γ xts
let γs = zipWith makeRecInvariants [γ' `setTRec` zip vars rts' | rts' <- rts] (filter (not . noMakeRec) <$> vs)
let xets' = zip3 vars es ts
mapM_ (uncurry $ consBind True) (zip γs xets')
return γ'
where
noMakeRec = if allowTC then GM.isEmbeddedDictVar else GM.isPredVar
allowTC = typeclass (getConfig γ)
(vars, es) = unzip xes
dxs = F.pprint <$> vars
collectArgs' = GM.collectArguments . length . ty_binds . toRTypeRep . unOCons . unTemplate
checkEqTypes :: [[Maybe SpecType]] -> CG [[SpecType]]
checkEqTypes x = mapM (checkAll' err1 toRSort) (catMaybes <$> x)
checkSameLens = checkAll' err2 length
err1 = ErrTermin loc dxs $ text "The decreasing parameters should be of same type"
err2 = ErrTermin loc dxs $ text "All Recursive functions should have the same number of decreasing parameters"
loc = getSrcSpan (head vars)
checkAll' _ _ [] = return []
checkAll' err f (x:xs)
| all (== f x) (f <$> xs) = return (x:xs)
| otherwise = addWarning err >> return []
consCBWithExprs :: CGEnv -> [(Var, CoreExpr)] -> CG CGEnv
consCBWithExprs γ xes
= do xets <- forM xes $ \(x, e) -> fmap (x, e,) (varTemplate γ (x, Just e))
texprs <- gets termExprs
let xtes = mapMaybe (`lookup'` texprs) xs
let ts = safeFromAsserted err . thd3 <$> xets
ts' <- mapM refreshArgs ts
let xts = zip xs (Asserted <$> ts')
γ' <- foldM extender γ xts
let γs = makeTermEnvs γ' xtes xes ts ts'
let xets' = zip3 xs es (Asserted <$> ts')
mapM_ (uncurry $ consBind True) (zip γs xets')
return γ'
where (xs, es) = unzip xes
lookup' k m | Just x <- M.lookup k m = Just (k, x)
| otherwise = Nothing
err = "Constant: consCBWithExprs"
makeTermEnvs :: CGEnv -> [(Var, [F.Located F.Expr])] -> [(Var, CoreExpr)]
-> [SpecType] -> [SpecType]
-> [CGEnv]
makeTermEnvs γ xtes xes ts ts' = setTRec γ . zip xs <$> rts
where
vs = zipWith collectArgs' ts ces
syms = fst5 . bkArrowDeep <$> ts
syms' = fst5 . bkArrowDeep <$> ts'
sus' = zipWith mkSub syms syms'
sus = zipWith mkSub syms ((F.symbol <$>) <$> vs)
ess = (\x -> safeFromJust (err x) (x `L.lookup` xtes)) <$> xs
tes = zipWith (\su es -> F.subst su <$> es) sus ess
tes' = zipWith (\su es -> F.subst su <$> es) sus' ess
rss = zipWith makeLexRefa tes' <$> (repeat <$> tes)
rts = zipWith (addObligation OTerm) ts' <$> rss
(xs, ces) = unzip xes
mkSub ys ys' = F.mkSubst [(x, F.EVar y) | (x, y) <- zip ys ys']
collectArgs' = GM.collectArguments . length . ty_binds . toRTypeRep
err x = "Constant: makeTermEnvs: no terminating expression for " ++ GM.showPpr x
addObligation :: Oblig -> SpecType -> RReft -> SpecType
addObligation o t r = mkArrow αs πs yts xts $ RRTy [] r o t2
where
(αs, πs, t1) = bkUniv t
((xs',is',ts',rs'),(xs, is, ts, rs), t2) = bkArrow t1
xts = zip4 xs is ts rs
yts = zip4 xs' is' ts' rs'
--------------------------------------------------------------------------------
consCB :: Bool -> Bool -> CGEnv -> CoreBind -> CG CGEnv
--------------------------------------------------------------------------------
-- do termination checking
consCB True _ γ (Rec xes)
= do texprs <- gets termExprs
modify $ \i -> i { recCount = recCount i + length xes }
let xxes = mapMaybe (`lookup'` texprs) xs
if null xxes
then consCBSizedTys γ xes
else check xxes <$> consCBWithExprs γ xes
where
xs = map fst xes
check ys r | length ys == length xs = r
| otherwise = panic (Just loc) msg
msg = "Termination expressions must be provided for all mutually recursive binders"
loc = getSrcSpan (head xs)
lookup' k m = (k,) <$> M.lookup k m
-- don't do termination checking, but some strata checks?
consCB _ False γ (Rec xes)
= do xets <- forM xes $ \(x, e) -> (x, e,) <$> varTemplate γ (x, Just e)
modify $ \i -> i { recCount = recCount i + length xes }
let xts = [(x, to) | (x, _, to) <- xets]
γ' <- foldM extender (γ `setRecs` (fst <$> xts)) xts
mapM_ (consBind True γ') xets
return γ'
-- don't do termination checking, and don't do any strata checks either?
consCB _ _ γ (Rec xes)
= do xets <- forM xes $ \(x, e) -> fmap (x, e,) (varTemplate γ (x, Just e))
modify $ \i -> i { recCount = recCount i + length xes }
let xts = [(x, to) | (x, _, to) <- xets]
γ' <- foldM extender (γ `setRecs` (fst <$> xts)) xts
mapM_ (consBind True γ') xets
return γ'
-- | NV: Dictionaries are not checked, because
-- | class methods' preconditions are not satisfied
consCB _ _ γ (NonRec x _) | isDictionary x
= do t <- trueTy (typeclass (getConfig γ)) (varType x)
extender γ (x, Assumed t)
where
isDictionary = isJust . dlookup (denv γ)
consCB _ _ γ (NonRec x _ ) | isHoleVar x && typedHoles (getConfig γ)
= return γ
consCB _ _ γ (NonRec x def)
| Just (w, τ) <- grepDictionary def
, Just d <- dlookup (denv γ) w
= do st <- mapM (trueTy (typeclass (getConfig γ))) τ
mapM_ addW (WfC γ <$> st)
let xts = dmap (fmap (f st)) d
let γ' = γ { denv = dinsert (denv γ) x xts }
t <- trueTy (typeclass (getConfig γ)) (varType x)
extender γ' (x, Assumed t)
where
f [t'] (RAllT α te _) = subsTyVarMeet' (ty_var_value α, t') te
f (t':ts) (RAllT α te _) = f ts $ subsTyVarMeet' (ty_var_value α, t') te
f _ _ = impossible Nothing "consCB on Dictionary: this should not happen"
consCB _ _ γ (NonRec x e)
= do to <- varTemplate γ (x, Nothing)
to' <- consBind False γ (x, e, to) >>= addPostTemplate γ
extender γ (x, makeSingleton γ (simplify e) <$> to')
grepDictionary :: CoreExpr -> Maybe (Var, [Type])
grepDictionary = go []
where
go ts (App (Var w) (Type t)) = Just (w, reverse (t:ts))
go ts (App e (Type t)) = go (t:ts) e
go ts (App e (Var _)) = go ts e
go ts (Let _ e) = go ts e
go _ _ = Nothing
--------------------------------------------------------------------------------
consBind :: Bool -> CGEnv -> (Var, CoreExpr, Template SpecType) -> CG (Template SpecType)
--------------------------------------------------------------------------------
consBind _ _ (x, _, Assumed t)
| RecSelId {} <- idDetails x -- don't check record selectors with assumed specs
= return $ F.notracepp ("TYPE FOR SELECTOR " ++ show x) $ Assumed t
consBind isRec' γ (x, e, Asserted spect)
= do let γ' = γ `setBind` x
(_,πs,_) = bkUniv spect
cgenv <- foldM addPToEnv γ' πs
-- take implcits out of the function's SpecType and into the env
let tyr = toRTypeRep spect
let spect' = fromRTypeRep (tyr { ty_ebinds = [], ty_einfo = [], ty_eargs = [], ty_erefts = [] })
γπ <- foldM (+=) cgenv $ (\(y,t)->("implicitError",y,t)) <$> zip (ty_ebinds tyr) (ty_eargs tyr)
cconsE γπ e (weakenResult (typeclass (getConfig γ)) x spect')
when (F.symbol x `elemHEnv` holes γ) $
-- have to add the wf constraint here for HOLEs so we have the proper env
addW $ WfC γπ $ fmap killSubst spect
addIdA x (defAnn isRec' spect)
return $ Asserted spect
consBind isRec' γ (x, e, Internal spect)
= do let γ' = γ `setBind` x
(_,πs,_) = bkUniv spect
γπ <- foldM addPToEnv γ' πs
let γπ' = γπ {cerr = Just $ ErrHMeas (getLocation γπ) (pprint x) (text explanation)}
cconsE γπ' e spect
when (F.symbol x `elemHEnv` holes γ) $
-- have to add the wf constraint here for HOLEs so we have the proper env
addW $ WfC γπ $ fmap killSubst spect
addIdA x (defAnn isRec' spect)
return $ Internal spect
where
explanation = "Cannot give singleton type to the function definition."
consBind isRec' γ (x, e, Assumed spect)
= do let γ' = γ `setBind` x
γπ <- foldM addPToEnv γ' πs
cconsE γπ e =<< true (typeclass (getConfig γ)) spect
addIdA x (defAnn isRec' spect)
return $ Asserted spect
where πs = ty_preds $ toRTypeRep spect
consBind isRec' γ (x, e, Unknown)
= do t' <- consE (γ `setBind` x) e
t <- topSpecType x t'
addIdA x (defAnn isRec' t)
when (GM.isExternalId x) (addKuts x t)
return $ Asserted t
killSubst :: RReft -> RReft
killSubst = fmap killSubstReft
killSubstReft :: F.Reft -> F.Reft
killSubstReft = trans kv () ()
where
kv = defaultVisitor { txExpr = ks }
ks _ (F.PKVar k _) = F.PKVar k mempty
ks _ p = p
defAnn :: Bool -> t -> Annot t
defAnn True = AnnRDf
defAnn False = AnnDef
addPToEnv :: CGEnv
-> PVar RSort -> CG CGEnv
addPToEnv γ π
= do γπ <- γ += ("addSpec1", pname π, pvarRType π)
foldM (+=) γπ [("addSpec2", x, ofRSort t) | (t, x, _) <- pargs π]
extender :: F.Symbolic a => CGEnv -> (a, Template SpecType) -> CG CGEnv
extender γ (x, Asserted t)
= case lookupREnv (F.symbol x) (assms γ) of
Just t' -> γ += ("extender", F.symbol x, t')
_ -> γ += ("extender", F.symbol x, t)
extender γ (x, Assumed t)
= γ += ("extender", F.symbol x, t)
extender γ _
= return γ
data Template a
= Asserted a
| Assumed a
| Internal a
| Unknown
deriving (Functor, F.Foldable, T.Traversable)
deriving instance (Show a) => (Show (Template a))
instance PPrint a => PPrint (Template a) where
pprintTidy k (Asserted t) = "Asserted" <+> pprintTidy k t
pprintTidy k (Assumed t) = "Assumed" <+> pprintTidy k t
pprintTidy k (Internal t) = "Internal" <+> pprintTidy k t
pprintTidy _ Unknown = "Unknown"
unTemplate :: Template t -> t
unTemplate (Asserted t) = t
unTemplate (Assumed t) = t
unTemplate (Internal t) = t
unTemplate _ = panic Nothing "Constraint.Generate.unTemplate called on `Unknown`"
addPostTemplate :: CGEnv
-> Template SpecType
-> CG (Template SpecType)
addPostTemplate γ (Asserted t) = Asserted <$> addPost γ t
addPostTemplate γ (Assumed t) = Assumed <$> addPost γ t
addPostTemplate γ (Internal t) = Internal <$> addPost γ t
addPostTemplate _ Unknown = return Unknown
safeFromAsserted :: [Char] -> Template t -> t
safeFromAsserted _ (Asserted t) = t
safeFromAsserted msg _ = panic Nothing $ "safeFromAsserted:" ++ msg
-- | @varTemplate@ is only called with a `Just e` argument when the `e`
-- corresponds to the body of a @Rec@ binder.
varTemplate :: CGEnv -> (Var, Maybe CoreExpr) -> CG (Template SpecType)
varTemplate γ (x, eo) = varTemplate' γ (x, eo) >>= mapM (topSpecType x)
-- | @lazVarTemplate@ is like `varTemplate` but for binders that are *not*
-- termination checked and hence, the top-level refinement / KVar is
-- stripped out. e.g. see tests/neg/T743.hs
-- varTemplate :: CGEnv -> (Var, Maybe CoreExpr) -> CG (Template SpecType)
-- lazyVarTemplate γ (x, eo) = dbg <$> (topRTypeBase <$>) <$> varTemplate' γ (x, eo)
-- where
-- dbg = traceShow ("LAZYVAR-TEMPLATE: " ++ show x)
varTemplate' :: CGEnv -> (Var, Maybe CoreExpr) -> CG (Template SpecType)
varTemplate' γ (x, eo)
= case (eo, lookupREnv (F.symbol x) (grtys γ), lookupREnv (F.symbol x) (assms γ), lookupREnv (F.symbol x) (intys γ)) of
(_, Just t, _, _) -> Asserted <$> refreshArgsTop (x, t)
(_, _, _, Just t) -> Internal <$> refreshArgsTop (x, t)
(_, _, Just t, _) -> Assumed <$> refreshArgsTop (x, t)
(Just e, _, _, _) -> do t <- freshTyExpr (typeclass (getConfig γ)) (RecBindE x) e (exprType e)
addW (WfC γ t)
Asserted <$> refreshArgsTop (x, t)
(_, _, _, _) -> return Unknown
-- | @topSpecType@ strips out the top-level refinement of "derived var"
topSpecType :: Var -> SpecType -> CG SpecType
topSpecType x t = do
info <- gets ghcI
return $ if derivedVar (giSrc info) x then topRTypeBase t else t
--------------------------------------------------------------------------------
-- | Bidirectional Constraint Generation: CHECKING -----------------------------
--------------------------------------------------------------------------------
cconsE :: CGEnv -> CoreExpr -> SpecType -> CG ()
--------------------------------------------------------------------------------
cconsE g e t = do
-- NOTE: tracing goes here
-- traceM $ printf "cconsE:\n expr = %s\n exprType = %s\n lqType = %s\n" (showPpr e) (showPpr (exprType e)) (showpp t)
cconsE' g e t
--------------------------------------------------------------------------------
cconsE' :: CGEnv -> CoreExpr -> SpecType -> CG ()
--------------------------------------------------------------------------------
cconsE' γ e t
| Just (Rs.PatSelfBind _x e') <- Rs.lift e
= cconsE' γ e' t
| Just (Rs.PatSelfRecBind x e') <- Rs.lift e
= let γ' = γ { grtys = insertREnv (F.symbol x) t (grtys γ)}
in void $ consCBLet γ' (Rec [(x, e')])
cconsE' γ e@(Let b@(NonRec x _) ee) t
= do sp <- gets specLVars
if x `S.member` sp
then cconsLazyLet γ e t
else do γ' <- consCBLet γ b
cconsE γ' ee t
cconsE' γ e (RAllP p t)
= cconsE γ' e t''
where
t' = replacePredsWithRefs su <$> t
su = (uPVar p, pVartoRConc p)
(css, t'') = splitConstraints (typeclass (getConfig γ)) t'
γ' = L.foldl' addConstraints γ css
cconsE' γ (Let b e) t
= do γ' <- consCBLet γ b
cconsE γ' e t
cconsE' γ (Case e x _ cases) t
= do γ' <- consCBLet γ (NonRec x e)
forM_ cases $ cconsCase γ' x t nonDefAlts
where
nonDefAlts = [a | (a, _, _) <- cases, a /= DEFAULT]
_msg = "cconsE' #nonDefAlts = " ++ show (length nonDefAlts)
cconsE' γ (Lam α e) (RAllT α' t r) | isTyVar α
= do γ' <- updateEnvironment γ α
addForAllConstraint γ' α e (RAllT α' t r)
cconsE γ' e $ subsTyVarMeet' (ty_var_value α', rVar α) t
cconsE' γ (Lam x e) (RFun y i ty t r)
| not (isTyVar x)
= do γ' <- γ += ("cconsE", x', ty)
cconsE γ' e t'
addFunctionConstraint γ x e (RFun x' i ty t' r')
addIdA x (AnnDef ty)
where
x' = F.symbol x
t' = t `F.subst1` (y, F.EVar x')
r' = r `F.subst1` (y, F.EVar x')
cconsE' γ (Tick tt e) t
= cconsE (γ `setLocation` Sp.Tick tt) e t
cconsE' γ (Cast e co) t
-- See Note [Type classes with a single method]
| Just f <- isClassConCo co
= cconsE γ (f e) t
cconsE' γ e@(Cast e' c) t
= do t' <- castTy γ (exprType e) e' c
addC (SubC γ (F.notracepp ("Casted Type for " ++ GM.showPpr e ++ "\n init type " ++ showpp t) t') t) ("cconsE Cast: " ++ GM.showPpr e)
cconsE' γ (Var x) t | isHoleVar x && typedHoles (getConfig γ)
= addHole x t γ
cconsE' γ e t
= do te <- consE γ e
te' <- instantiatePreds γ e te >>= addPost γ
addC (SubC γ te' t) ("cconsE: " ++ "\n t = " ++ showpp t ++ "\n te = " ++ showpp te ++ GM.showPpr e)
lambdaSingleton :: CGEnv -> F.TCEmb TyCon -> Var -> CoreExpr -> CG (UReft F.Reft)
lambdaSingleton γ tce x e
| higherOrderFlag γ
= lamExpr γ e >>= \case
Just e' -> return $ uTop $ F.exprReft $ F.ELam (F.symbol x, sx) e'
_ -> return mempty
where
sx = typeSort tce $ Ghc.expandTypeSynonyms $ varType x
lambdaSingleton _ _ _ _
= return mempty
addForAllConstraint :: CGEnv -> Var -> CoreExpr -> SpecType -> CG ()
addForAllConstraint γ _ _ (RAllT rtv rt rr)
| F.isTauto rr
= return ()
| otherwise
= do t' <- true (typeclass (getConfig γ)) rt
let truet = RAllT rtv $ unRAllP t'
addC (SubC γ (truet mempty) $ truet rr) "forall constraint true"
where unRAllP (RAllT a t r) = RAllT a (unRAllP t) r
unRAllP (RAllP _ t) = unRAllP t
unRAllP t = t
addForAllConstraint γ _ _ _
= impossible (Just $ getLocation γ) "addFunctionConstraint: called on non function argument"
addFunctionConstraint :: CGEnv -> Var -> CoreExpr -> SpecType -> CG ()
addFunctionConstraint γ x e (RFun y i ty t r)
= do ty' <- true (typeclass (getConfig γ)) ty
t' <- true (typeclass (getConfig γ)) t
let truet = RFun y i ty' t'
lamE <- lamExpr γ e
case (lamE, higherOrderFlag γ) of
(Just e', True) -> do tce <- gets tyConEmbed
let sx = typeSort tce $ varType x
let ref = uTop $ F.exprReft $ F.ELam (F.symbol x, sx) e'
addC (SubC γ (truet ref) $ truet r) "function constraint singleton"
_ -> addC (SubC γ (truet mempty) $ truet r) "function constraint true"
addFunctionConstraint γ _ _ _
= impossible (Just $ getLocation γ) "addFunctionConstraint: called on non function argument"
splitConstraints :: TyConable c
=> Bool -> RType c tv r -> ([[(F.Symbol, RType c tv r)]], RType c tv r)
splitConstraints allowTC (RRTy cs _ OCons t)
= let (css, t') = splitConstraints allowTC t in (cs:css, t')
splitConstraints allowTC (RFun x i tx@(RApp c _ _ _) t r) | isErasable c
= let (css, t') = splitConstraints allowTC t in (css, RFun x i tx t' r)
where isErasable = if allowTC then isEmbeddedDict else isClass
splitConstraints _ t
= ([], t)
-------------------------------------------------------------------
-- | @instantiateGhosts@ peels away implicit argument binders,
-- instantiates them with fresh variables, and adds those variables
-- to the context as @ebind@s TODO: the second half
-------------------------------------------------------------------
instantiateGhosts :: CGEnv
-> SpecType
-> CG (Bool, CGEnv, SpecType)
instantiateGhosts γ t | not (null yts)
= do ys' <- mapM (const fresh) ys
γ' <- foldM addEEnv γ (zip ys' ts)
let su = F.mkSubst $ zip ys (F.EVar <$> ys')
return (True, γ', F.subst su te')
where (yts, te') = bkImplicit t
(ys, ts) = unzip yts
instantiateGhosts γ t = return (False, γ, t)
bkImplicit :: RType c tv r
-> ( [(F.Symbol, RType c tv r)]
, RType c tv r)
bkImplicit (RImpF x _ tx t _) = ((x,tx):acc, t')
where (acc,t') = bkImplicit t
bkImplicit t = ([],t)
-------------------------------------------------------------------
-- | @instantiatePreds@ peels away the universally quantified @PVars@
-- of a @RType@, generates fresh @Ref@ for them and substitutes them
-- in the body.
-------------------------------------------------------------------
instantiatePreds :: CGEnv
-> CoreExpr
-> SpecType
-> CG SpecType
instantiatePreds γ e (RAllP π t)
= do r <- freshPredRef γ e π
instantiatePreds γ e $ replacePreds "consE" t [(π, r)]
instantiatePreds _ _ t0
= return t0
-------------------------------------------------------------------
cconsLazyLet :: CGEnv
-> CoreExpr
-> SpecType
-> CG ()
cconsLazyLet γ (Let (NonRec x ex) e) t
= do tx <- trueTy (typeclass (getConfig γ)) (varType x)
γ' <- (γ, "Let NonRec") +++= (x', ex, tx)
cconsE γ' e t
where
x' = F.symbol x
cconsLazyLet _ _ _
= panic Nothing "Constraint.Generate.cconsLazyLet called on invalid inputs"
--------------------------------------------------------------------------------
-- | Bidirectional Constraint Generation: SYNTHESIS ----------------------------
--------------------------------------------------------------------------------
consE :: CGEnv -> CoreExpr -> CG SpecType
--------------------------------------------------------------------------------
consE γ e
| patternFlag γ
, Just p <- Rs.lift e
= consPattern γ (F.notracepp "CONSE-PATTERN: " p) (exprType e)
-- NV CHECK 3 (unVar and does this hack even needed?)
-- NV (below) is a hack to type polymorphic axiomatized functions
-- no need to check this code with flag, the axioms environment with
-- is empty if there is no axiomatization.
-- [NOTE: PLE-OPT] We *disable* refined instantiation for
-- reflected functions inside proofs.
-- If datacon definitions have references to self for fancy termination,
-- ignore them at the construction.
consE γ (Var x) | GM.isDataConId x
= do t0 <- varRefType γ x
-- NV: The check is expected to fail most times, so
-- it is cheaper than direclty fmap ignoreSelf.
let hasSelf = selfSymbol `elem` F.syms t0
let t = if hasSelf
then fmap ignoreSelf <$> t0
else t0
addLocA (Just x) (getLocation γ) (varAnn γ x t)
return t
consE γ (Var x)
= do t <- varRefType γ x
addLocA (Just x) (getLocation γ) (varAnn γ x t)
return t
consE _ (Lit c)
= refreshVV $ uRType $ literalFRefType c
consE γ e'@(App e a@(Type τ))
= do RAllT α te _ <- checkAll ("Non-all TyApp with expr", e) γ <$> consE γ e
t <- if not (nopolyinfer (getConfig γ)) && isPos α && isGenericVar (ty_var_value α) te
then freshTyType (typeclass (getConfig γ)) TypeInstE e τ
else trueTy (typeclass (getConfig γ)) τ
addW $ WfC γ t
t' <- refreshVV t
tt0 <- instantiatePreds γ e' (subsTyVarMeet' (ty_var_value α, t') te)
let tt = makeSingleton γ (simplify e') $ subsTyReft γ (ty_var_value α) τ tt0
case rTVarToBind α of
Just (x, _) -> return $ maybe (checkUnbound γ e' x tt a) (F.subst1 tt . (x,)) (argType τ)
Nothing -> return tt
where
isPos α = not (extensionality (getConfig γ)) || rtv_is_pol (ty_var_info α)
consE γ e'@(App e a) | Just aDict <- getExprDict γ a
= case dhasinfo (dlookup (denv γ) aDict) (getExprFun γ e) of
Just riSig -> return $ fromRISig riSig
_ -> do
([], πs, te) <- bkUniv <$> consE γ e
te' <- instantiatePreds γ e' $ foldr RAllP te πs
(γ', te''') <- dropExists γ te'
te'' <- dropConstraints γ te'''
updateLocA {- πs -} (exprLoc e) te''
let RFun x _ tx t _ = checkFun ("Non-fun App with caller ", e') γ te''
cconsE γ' a tx
addPost γ' $ maybe (checkUnbound γ' e' x t a) (F.subst1 t . (x,)) (argExpr γ a)
consE γ e'@(App e a)
= do ([], πs, te) <- bkUniv <$> consE γ {- GM.tracePpr ("APP-EXPR: " ++ GM.showPpr (exprType e)) -} e
te1 <- instantiatePreds γ e' $ foldr RAllP te πs
(γ', te2) <- dropExists γ te1
te3 <- dropConstraints γ te2
updateLocA (exprLoc e) te3
(hasGhost, γ'', te4) <- instantiateGhosts γ' te3
let RFun x _ tx t _ = checkFun ("Non-fun App with caller ", e') γ te4
cconsE γ'' a tx
tout <- makeSingleton γ'' (simplify e') <$> addPost γ'' (maybe (checkUnbound γ'' e' x t a) (F.subst1 t . (x,)) (argExpr γ $ simplify a))
if hasGhost
then do
tk <- freshTyType (typeclass (getConfig γ)) ImplictE e' $ exprType e'
addW $ WfC γ tk
addC (SubC γ'' tout tk) ""
return tk
else return tout
consE γ (Lam α e) | isTyVar α
= do γ' <- updateEnvironment γ α
t' <- consE γ' e
return $ RAllT (makeRTVar $ rTyVar α) t' mempty
consE γ e@(Lam x e1)
= do tx <- freshTyType (typeclass (getConfig γ)) LamE (Var x) τx
γ' <- γ += ("consE", F.symbol x, tx)
t1 <- consE γ' e1
addIdA x $ AnnDef tx
addW $ WfC γ tx
tce <- gets tyConEmbed
lamSing <- lambdaSingleton γ tce x e1
return $ RFun (F.symbol x) (mkRFInfo $ getConfig γ) tx t1 lamSing
where
FunTy { ft_arg = τx } = exprType e
consE γ e@(Let _ _)
= cconsFreshE LetE γ e
consE γ e@(Case _ _ _ [_])
| Just p@Rs.PatProject{} <- Rs.lift e
= consPattern γ p (exprType e)
consE γ e@(Case _ _ _ cs)
= cconsFreshE (caseKVKind cs) γ e
consE γ (Tick tt e)
= do t <- consE (setLocation γ (Sp.Tick tt)) e
addLocA Nothing (GM.tickSrcSpan tt) (AnnUse t)
return t
-- See Note [Type classes with a single method]
consE γ (Cast e co)
| Just f <- isClassConCo co
= consE γ (f e)
consE γ e@(Cast e' c)
= castTy γ (exprType e) e' c
consE γ e@(Coercion _)
= trueTy (typeclass (getConfig γ)) $ exprType e
consE _ e@(Type t)
= panic Nothing $ "consE cannot handle type " ++ GM.showPpr (e, t)
caseKVKind ::[Alt Var] -> KVKind
caseKVKind [(DataAlt _, _, Var _)] = ProjectE
caseKVKind cs = CaseE (length cs)
updateEnvironment :: CGEnv -> TyVar -> CG CGEnv
updateEnvironment γ a
| isValKind (tyVarKind a)
= γ += ("varType", F.symbol $ varName a, kindToRType $ tyVarKind a)
| otherwise
= return γ
getExprFun :: CGEnv -> CoreExpr -> Var
getExprFun γ e = go e
where
go (App x (Type _)) = go x
go (Var x) = x
go _ = panic (Just (getLocation γ)) msg
msg = "getFunName on \t" ++ GM.showPpr e
-- | `exprDict e` returns the dictionary `Var` inside the expression `e`
getExprDict :: CGEnv -> CoreExpr -> Maybe Var
getExprDict γ = go
where
go (Var x) = case dlookup (denv γ) x of {Just _ -> Just x; Nothing -> Nothing}
go (Tick _ e) = go e
go (App a (Type _)) = go a
go (Let _ e) = go e
go _ = Nothing
--------------------------------------------------------------------------------
-- | With GADTs and reflection, refinements can contain type variables,
-- as 'coercions' (see ucsd-progsys/#1424). At application sites, we
-- must also substitute those from the refinements (not just the types).
-- https://github.com/ucsd-progsys/liquidhaskell/issues/1424
--
-- see: tests/ple/{pos,neg}/T1424.hs
--
--------------------------------------------------------------------------------
subsTyReft :: CGEnv -> RTyVar -> Type -> SpecType -> SpecType
subsTyReft γ a t = mapExprReft (\_ -> F.applyCoSub coSub)
where
coSub = M.fromList [(F.symbol a, typeSort (emb γ) t)]
--------------------------------------------------------------------------------
-- | Type Synthesis for Special @Pattern@s -------------------------------------
--------------------------------------------------------------------------------
consPattern :: CGEnv -> Rs.Pattern -> Type -> CG SpecType
{- [NOTE] special type rule for monadic-bind application
G |- e1 ~> m tx G, x:tx |- e2 ~> m t
-----------------------------------------
G |- (e1 >>= \x -> e2) ~> m t
-}
consPattern γ (Rs.PatBind e1 x e2 _ _ _ _ _) _ = do
tx <- checkMonad (msg, e1) γ <$> consE γ e1
γ' <- γ += ("consPattern", F.symbol x, tx)
addIdA x (AnnDef tx)
consE γ' e2
where
msg = "This expression has a refined monadic type; run with --no-pattern-inline: "
{- [NOTE] special type rule for monadic-return
G |- e ~> et
------------------------
G |- return e ~ m et
-}
consPattern γ (Rs.PatReturn e m _ _ _) t = do
et <- F.notracepp "Cons-Pattern-Ret" <$> consE γ e
mt <- trueTy (typeclass (getConfig γ)) m
tt <- trueTy (typeclass (getConfig γ)) t
return (mkRAppTy mt et tt) -- /// {- $ RAppTy mt et mempty -}
{- [NOTE] special type rule for field projection, is
t = G(x) ti = Proj(t, i)
-----------------------------------------
G |- case x of C [y1...yn] -> yi : ti
-}
consPattern γ (Rs.PatProject xe _ τ c ys i) _ = do
let yi = ys !! i
t <- (addW . WfC γ) <<= freshTyType (typeclass (getConfig γ)) ProjectE (Var yi) τ
γ' <- caseEnv γ xe [] (DataAlt c) ys (Just [i])
ti <- {- γ' ??= yi -} varRefType γ' yi
addC (SubC γ' ti t) "consPattern:project"
return t
consPattern γ (Rs.PatSelfBind _ e) _ =
consE γ e
consPattern γ p@Rs.PatSelfRecBind{} _ =
cconsFreshE LetE γ (Rs.lower p)
mkRAppTy :: SpecType -> SpecType -> SpecType -> SpecType
mkRAppTy mt et RAppTy{} = RAppTy mt et mempty
mkRAppTy _ et (RApp c [_] [] _) = RApp c [et] [] mempty
mkRAppTy _ _ _ = panic Nothing "Unexpected return-pattern"
checkMonad :: (Outputable a) => (String, a) -> CGEnv -> SpecType -> SpecType
checkMonad x g = go . unRRTy
where
go (RApp _ ts [] _)
| not (null ts) = last ts
go (RAppTy _ t _) = t
go t = checkErr x g t
unRRTy :: SpecType -> SpecType
unRRTy (RRTy _ _ _ t) = unRRTy t
unRRTy t = t
--------------------------------------------------------------------------------
castTy :: CGEnv -> Type -> CoreExpr -> Coercion -> CG SpecType
castTy' :: CGEnv -> Type -> CoreExpr -> CG SpecType
--------------------------------------------------------------------------------
castTy γ t e (AxiomInstCo ca _ _)
= fromMaybe <$> castTy' γ t e <*> lookupNewType (coAxiomTyCon ca)
castTy γ t e (SymCo (AxiomInstCo ca _ _))
= do mtc <- lookupNewType (coAxiomTyCon ca)
F.forM_ mtc (cconsE γ e)
castTy' γ t e
castTy γ t e _
= castTy' γ t e
castTy' γ τ (Var x)
= do t0 <- trueTy (typeclass (getConfig γ)) τ
tx <- varRefType γ x
let t = mergeCastTys t0 tx
let ce = if typeclass (getConfig γ) && noADT (getConfig γ) then F.expr x
else eCoerc (typeSort (emb γ) $ Ghc.expandTypeSynonyms $ varType x)
(typeSort (emb γ) τ)
$ F.expr x
return (t `strengthen` uTop (F.uexprReft ce) {- `F.meet` tx -})
where eCoerc s t e
| s == t = e
| otherwise = F.ECoerc s t e
castTy' γ t (Tick _ e)
= castTy' γ t e
castTy' _ _ e
= panic Nothing $ "castTy cannot handle expr " ++ GM.showPpr e
{-
mergeCastTys tcorrect trefined
tcorrect has the correct GHC skeleton,
trefined has the correct refinements (before coercion)
mergeCastTys keeps the trefined when the two GHC types match
-}
mergeCastTys :: SpecType -> SpecType -> SpecType
mergeCastTys t1 t2
| toType False t1 == toType False t2
= t2
mergeCastTys (RApp c1 ts1 ps1 r1) (RApp c2 ts2 _ _)
| c1 == c2
= RApp c1 (zipWith mergeCastTys ts1 ts2) ps1 r1
mergeCastTys t _
= t
{-
showCoercion :: Coercion -> String
showCoercion (AxiomInstCo co1 co2 co3)
= "AxiomInstCo " ++ showPpr co1 ++ "\t\t " ++ showPpr co2 ++ "\t\t" ++ showPpr co3 ++ "\n\n" ++
"COAxiom Tycon = " ++ showPpr (coAxiomTyCon co1) ++ "\nBRANCHES\n" ++ concatMap showBranch bs
where
bs = fromBranchList $ co_ax_branches co1
showBranch ab = "\nCoAxiom \nLHS = " ++ showPpr (coAxBranchLHS ab) ++
"\nRHS = " ++ showPpr (coAxBranchRHS ab)
showCoercion (SymCo c)
= "Symc :: " ++ showCoercion c
showCoercion c
= "Coercion " ++ showPpr c
-}
isClassConCo :: Coercion -> Maybe (Expr Var -> Expr Var)
-- See Note [Type classes with a single method]
isClassConCo co
| Pair t1 t2 <- coercionKind co
, isClassPred t2
, (tc,ts) <- splitTyConApp t2
, [dc] <- tyConDataCons tc
, [tm] <- map irrelevantMult (Ghc.dataConOrigArgTys dc)
-- tcMatchTy because we have to instantiate the class tyvars
, Just _ <- ruleMatchTyX (mkUniqSet $ tyConTyVars tc) (mkRnEnv2 emptyInScopeSet) emptyTvSubstEnv tm t1
= Just (\e -> mkCoreConApps dc $ map Type ts ++ [e])
| otherwise
= Nothing
where
ruleMatchTyX =ruleMatchTyKiX -- TODO: is this correct?
----------------------------------------------------------------------
-- Note [Type classes with a single method]
----------------------------------------------------------------------
-- GHC 7.10 encodes type classes with a single method as newtypes and
-- `cast`s between the method and class type instead of applying the
-- class constructor. Just rewrite the core to what we're used to
-- seeing..
--
-- specifically, we want to rewrite
--
-- e `cast` ((a -> b) ~ C)
--
-- to
--
-- D:C e
--
-- but only when
--
-- D:C :: (a -> b) -> C
--------------------------------------------------------------------------------
-- | @consFreshE@ is used to *synthesize* types with a **fresh template**.
-- e.g. at joins, recursive binders, polymorphic instantiations etc. It is
-- the "portal" that connects `consE` (synthesis) and `cconsE` (checking)
--------------------------------------------------------------------------------
cconsFreshE :: KVKind -> CGEnv -> CoreExpr -> CG SpecType
cconsFreshE kvkind γ e = do
t <- freshTyType (typeclass (getConfig γ)) kvkind e $ exprType e
addW $ WfC γ t
cconsE γ e t
return t
--------------------------------------------------------------------------------
checkUnbound :: (Show a, Show a2, F.Subable a)
=> CGEnv -> CoreExpr -> F.Symbol -> a -> a2 -> a
checkUnbound γ e x t a
| x `notElem` F.syms t = t
| otherwise = panic (Just $ getLocation γ) msg
where
msg = unlines [ "checkUnbound: " ++ show x ++ " is elem of syms of " ++ show t
, "In", GM.showPpr e, "Arg = " , show a ]
dropExists :: CGEnv -> SpecType -> CG (CGEnv, SpecType)
dropExists γ (REx x tx t) = (, t) <$> γ += ("dropExists", x, tx)
dropExists γ t = return (γ, t)
dropConstraints :: CGEnv -> SpecType -> CG SpecType
dropConstraints cgenv (RFun x i tx@(RApp c _ _ _) t r) | isErasable c
= flip (RFun x i tx) r <$> dropConstraints cgenv t
where
isErasable = if typeclass (getConfig cgenv) then isEmbeddedDict else isClass
dropConstraints cgenv (RRTy cts _ OCons rt)
= do γ' <- foldM (\γ (x, t) -> γ `addSEnv` ("splitS", x,t)) cgenv xts
addC (SubC γ' t1 t2) "dropConstraints"
dropConstraints cgenv rt
where
(xts, t1, t2) = envToSub cts
dropConstraints _ t = return t
-------------------------------------------------------------------------------------
cconsCase :: CGEnv -> Var -> SpecType -> [AltCon] -> (AltCon, [Var], CoreExpr) -> CG ()
-------------------------------------------------------------------------------------
cconsCase γ x t acs (ac, ys, ce)
= do cγ <- caseEnv γ x acs ac ys mempty
cconsE cγ ce t
{-
case x :: List b of
Emp -> e
Emp :: tdc forall a. {v: List a | cons v === 0}
x :: xt List b
ys == binders []
-}
-------------------------------------------------------------------------------------
caseEnv :: CGEnv -> Var -> [AltCon] -> AltCon -> [Var] -> Maybe [Int] -> CG CGEnv
-------------------------------------------------------------------------------------
caseEnv γ x _ (DataAlt c) ys pIs = do
let (x' : ys') = F.symbol <$> (x:ys)
xt0 <- checkTyCon ("checkTycon cconsCase", x) γ <$> γ ??= x
let rt = shiftVV xt0 x'
tdc <- γ ??= dataConWorkId c >>= refreshVV
let (rtd,yts',_) = unfoldR tdc rt ys
yts <- projectTypes (typeclass (getConfig γ)) pIs yts'
let ys'' = F.symbol <$> filter (not . if allowTC then GM.isEmbeddedDictVar else GM.isEvVar) ys
let r1 = dataConReft c ys''
let r2 = dataConMsReft rtd ys''
let xt = (xt0 `F.meet` rtd) `strengthen` uTop (r1 `F.meet` r2)
let cbs = safeZip "cconsCase" (x':ys')
(map (`F.subst1` (selfSymbol, F.EVar x'))
(xt0 : yts))
cγ' <- addBinders γ x' cbs
addBinders cγ' x' [(x', substSelf <$> xt)]
where allowTC = typeclass (getConfig γ)
caseEnv γ x acs a _ _ = do
let x' = F.symbol x
xt' <- (`strengthen` uTop (altReft γ acs a)) <$> (γ ??= x)
addBinders γ x' [(x', xt')]
------------------------------------------------------
-- SELF special substitutions
------------------------------------------------------
substSelf :: UReft F.Reft -> UReft F.Reft
substSelf (MkUReft r p) = MkUReft (substSelfReft r) p
substSelfReft :: F.Reft -> F.Reft
substSelfReft (F.Reft (v, e)) = F.Reft (v, F.subst1 e (selfSymbol, F.EVar v))
ignoreSelf :: F.Reft -> F.Reft
ignoreSelf = F.mapExpr (\r -> if selfSymbol `elem` F.syms r then F.PTrue else r)
--------------------------------------------------------------------------------
-- | `projectTypes` masks (i.e. true's out) all types EXCEPT those
-- at given indices; it is used to simplify the environment used
-- when projecting out fields of single-ctor datatypes.
--------------------------------------------------------------------------------
projectTypes :: Bool -> Maybe [Int] -> [SpecType] -> CG [SpecType]
projectTypes _ Nothing ts = return ts
projectTypes allowTC (Just ints) ts = mapM (projT ints) (zip [0..] ts)
where
projT is (j, t)
| j `elem` is = return t
| otherwise = true allowTC t
altReft :: CGEnv -> [AltCon] -> AltCon -> F.Reft
altReft _ _ (LitAlt l) = literalFReft l
altReft γ acs DEFAULT = mconcat ([notLiteralReft l | LitAlt l <- acs] ++ [notDataConReft d | DataAlt d <- acs])
where
notLiteralReft = maybe mempty F.notExprReft . snd . literalConst (emb γ)
notDataConReft d | exactDC (getConfig γ)
= F.Reft (F.vv_, F.PNot (F.EApp (F.EVar $ makeDataConChecker d) (F.EVar F.vv_)))
| otherwise = mempty
altReft _ _ _ = panic Nothing "Constraint : altReft"
unfoldR :: SpecType -> SpecType -> [Var] -> (SpecType, [SpecType], SpecType)
unfoldR td (RApp _ ts rs _) ys = (t3, tvys ++ yts, ignoreOblig rt)
where
tbody = instantiatePvs (instantiateTys td ts) (reverse rs)
-- TODO: if we ever want to support applying implicits explicitly, will need to rejigger
((_,_,_,_),(ys0,_,yts',_), rt) = safeBkArrow (F.notracepp msg $ instantiateTys tbody tvs')
msg = "INST-TY: " ++ F.showpp (td, ts, tbody, ys, tvs')
yts'' = zipWith F.subst sus (yts'++[rt])
(t3,yts) = (last yts'', init yts'')
sus = F.mkSubst <$> L.inits [(x, F.EVar y) | (x, y) <- zip ys0 ys']
(αs, ys') = mapSnd (F.symbol <$>) $ L.partition isTyVar ys
tvs' :: [SpecType]
tvs' = rVar <$> αs
tvys = ofType . varType <$> αs
unfoldR _ _ _ = panic Nothing "Constraint.hs : unfoldR"
instantiateTys :: SpecType -> [SpecType] -> SpecType
instantiateTys = L.foldl' go
where
go (RAllT α tbody _) t = subsTyVarMeet' (ty_var_value α, t) tbody
go _ _ = panic Nothing "Constraint.instantiateTy"
instantiatePvs :: SpecType -> [SpecProp] -> SpecType
instantiatePvs = L.foldl' go
where
go (RAllP p tbody) r = replacePreds "instantiatePv" tbody [(p, r)]
go t _ = errorP "" ("Constraint.instantiatePvs: t = " ++ showpp t)
checkTyCon :: (Outputable a) => (String, a) -> CGEnv -> SpecType -> SpecType
checkTyCon _ _ t@RApp{} = t
checkTyCon x g t = checkErr x g t
checkFun :: (Outputable a) => (String, a) -> CGEnv -> SpecType -> SpecType
checkFun _ _ t@RFun{} = t
checkFun x g t = checkErr x g t
checkAll :: (Outputable a) => (String, a) -> CGEnv -> SpecType -> SpecType
checkAll _ _ t@RAllT{} = t
checkAll x g t = checkErr x g t
checkErr :: (Outputable a) => (String, a) -> CGEnv -> SpecType -> SpecType
checkErr (msg, e) γ t = panic (Just sp) $ msg ++ GM.showPpr e ++ ", type: " ++ showpp t
where
sp = getLocation γ
varAnn :: CGEnv -> Var -> t -> Annot t
varAnn γ x t
| x `S.member` recs γ = AnnLoc (getSrcSpan x)
| otherwise = AnnUse t
-----------------------------------------------------------------------
-- | Helpers: Creating Fresh Refinement -------------------------------
-----------------------------------------------------------------------
freshPredRef :: CGEnv -> CoreExpr -> PVar RSort -> CG SpecProp
freshPredRef γ e (PV _ (PVProp rsort) _ as)
= do t <- freshTyType (typeclass (getConfig γ)) PredInstE e (toType False rsort)
args <- mapM (const fresh) as
let targs = [(x, s) | (x, (s, y, z)) <- zip args as, F.EVar y == z ]
γ' <- foldM (+=) γ [("freshPredRef", x, ofRSort τ) | (x, τ) <- targs]
addW $ WfC γ' t
return $ RProp targs t
freshPredRef _ _ (PV _ PVHProp _ _)
= todo Nothing "EFFECTS:freshPredRef"
--------------------------------------------------------------------------------
-- | Helpers: Creating Refinement Types For Various Things ---------------------
--------------------------------------------------------------------------------
argType :: Type -> Maybe F.Expr
argType (LitTy (NumTyLit i))
= mkI i
argType (LitTy (StrTyLit s))
= mkS $ bytesFS s
argType (TyVarTy x)
= Just $ F.EVar $ F.symbol $ varName x
argType t
| F.symbol (GM.showPpr t) == anyTypeSymbol
= Just $ F.EVar anyTypeSymbol
argType _
= Nothing
argExpr :: CGEnv -> CoreExpr -> Maybe F.Expr
argExpr _ (Var v) = Just $ F.eVar v
argExpr γ (Lit c) = snd $ literalConst (emb γ) c
argExpr γ (Tick _ e) = argExpr γ e
argExpr γ (App e (Type _)) = argExpr γ e
argExpr _ _ = Nothing
lamExpr :: CGEnv -> CoreExpr -> CG (Maybe F.Expr)
lamExpr g e = do
adts <- gets cgADTs
allowTC <- gets cgiTypeclass
let dm = dataConMap adts
case runToLogic (emb g) mempty dm (\x -> todo Nothing ("coreToLogic not working lamExpr: " ++ x)) (coreToLogic allowTC e) of
Left _ -> return Nothing
Right ce -> return (Just ce)
--------------------------------------------------------------------------------
(??=) :: (?callStack :: CallStack) => CGEnv -> Var -> CG SpecType
--------------------------------------------------------------------------------
γ ??= x = case M.lookup x' (lcb γ) of
Just e -> consE (γ -= x') e
Nothing -> refreshTy tx
where
x' = F.symbol x
tx = fromMaybe tt (γ ?= x')
tt = ofType $ varType x
--------------------------------------------------------------------------------
varRefType :: (?callStack :: CallStack) => CGEnv -> Var -> CG SpecType
--------------------------------------------------------------------------------
varRefType γ x =
varRefType' γ x <$> (γ ??= x) -- F.tracepp (printf "varRefType x = [%s]" (showpp x))
varRefType' :: CGEnv -> Var -> SpecType -> SpecType
varRefType' γ x t'
| Just tys <- trec γ, Just tr <- M.lookup x' tys
= strengthen' tr xr
| otherwise
= strengthen' t' xr
where
xr = singletonReft x
x' = F.symbol x
strengthen'
| higherOrderFlag γ
= strengthenMeet
| otherwise
= strengthenTop
-- | create singleton types for function application
makeSingleton :: CGEnv -> CoreExpr -> SpecType -> SpecType
makeSingleton γ cexpr t
| higherOrderFlag γ, App f x <- simplify cexpr
= case (funExpr γ f, argForAllExpr x) of
(Just f', Just x')
| not (if typeclass (getConfig γ) then GM.isEmbeddedDictExpr x else GM.isPredExpr x) -- (isClassPred $ exprType x)
-> strengthenMeet t (uTop $ F.exprReft (F.EApp f' x'))
(Just f', Just _)
-> strengthenMeet t (uTop $ F.exprReft f')
_ -> t
| rankNTypes (getConfig γ)
= case argExpr γ (simplify cexpr) of
Just e' -> strengthenMeet t $ uTop (F.exprReft e')
_ -> t
| otherwise
= t
where
argForAllExpr (Var x)
| rankNTypes (getConfig γ)
, Just e <- M.lookup x (forallcb γ)
= Just e
argForAllExpr e
= argExpr γ e
funExpr :: CGEnv -> CoreExpr -> Maybe F.Expr
funExpr _ (Var v)
= Just $ F.EVar (F.symbol v)
funExpr γ (App e1 e2)
= case (funExpr γ e1, argExpr γ e2) of
(Just e1', Just e2') | not (if typeclass (getConfig γ) then GM.isEmbeddedDictExpr e2 else GM.isPredExpr e2) -- (isClassPred $ exprType e2)
-> Just (F.EApp e1' e2')
(Just e1', Just _)
-> Just e1'
_ -> Nothing
funExpr _ _
= Nothing
simplify :: CoreExpr -> CoreExpr
simplify (Tick _ e) = simplify e
simplify (App e (Type _)) = simplify e
simplify (App e1 e2) = App (simplify e1) (simplify e2)
simplify (Lam x e) | isTyVar x = simplify e
simplify e = e
singletonReft :: (F.Symbolic a) => a -> UReft F.Reft
singletonReft = uTop . F.symbolReft . F.symbol
-- | RJ: `nomeet` replaces `strengthenS` for `strengthen` in the definition
-- of `varRefType`. Why does `tests/neg/strata.hs` fail EVEN if I just replace
-- the `otherwise` case? The fq file holds no answers, both are sat.
strengthenTop :: (PPrint r, F.Reftable r) => RType c tv r -> r -> RType c tv r
strengthenTop (RApp c ts rs r) r' = RApp c ts rs $ F.meet r r'
strengthenTop (RVar a r) r' = RVar a $ F.meet r r'
strengthenTop (RFun b i t1 t2 r) r'= RFun b i t1 t2 $ F.meet r r'
strengthenTop (RAppTy t1 t2 r) r' = RAppTy t1 t2 $ F.meet r r'
strengthenTop (RAllT a t r) r' = RAllT a t $ F.meet r r'
strengthenTop t _ = t
-- TODO: this is almost identical to RT.strengthen! merge them!
strengthenMeet :: (PPrint r, F.Reftable r) => RType c tv r -> r -> RType c tv r
strengthenMeet (RApp c ts rs r) r' = RApp c ts rs (r `F.meet` r')
strengthenMeet (RVar a r) r' = RVar a (r `F.meet` r')
strengthenMeet (RFun b i t1 t2 r) r'= RFun b i t1 t2 (r `F.meet` r')
strengthenMeet (RAppTy t1 t2 r) r' = RAppTy t1 t2 (r `F.meet` r')
strengthenMeet (RAllT a t r) r' = RAllT a (strengthenMeet t r') (r `F.meet` r')
strengthenMeet t _ = t
-- topMeet :: (PPrint r, F.Reftable r) => r -> r -> r
-- topMeet r r' = r `F.meet` r'
--------------------------------------------------------------------------------
-- | Cleaner Signatures For Rec-bindings ---------------------------------------
--------------------------------------------------------------------------------
exprLoc :: CoreExpr -> Maybe SrcSpan
exprLoc (Tick tt _) = Just $ GM.tickSrcSpan tt
exprLoc (App e a) | isType a = exprLoc e
exprLoc _ = Nothing
isType :: Expr CoreBndr -> Bool
isType (Type _) = True
isType a = eqType (exprType a) predType
-- | @isGenericVar@ determines whether the @RTyVar@ has no class constraints
isGenericVar :: RTyVar -> SpecType -> Bool
isGenericVar α st = all (\(c, α') -> (α'/=α) || isGenericClass c ) (classConstrs st)
where
classConstrs t = [(c, ty_var_value α')
| (c, ts) <- tyClasses t
, t' <- ts
, α' <- freeTyVars t']
isGenericClass c = className c `elem` [ordClassName, eqClassName] -- , functorClassName, monadClassName]
-- instance MonadFail CG where
-- fail msg = panic Nothing msg
instance MonadFail Data.Functor.Identity.Identity where
fail msg = panic Nothing msg