liquidhaskell-0.8.0.0: src/Language/Haskell/Liquid/Constraint/Qualifier.hs
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE ViewPatterns #-}
{-# LANGUAGE PartialTypeSignatures #-}
{-# LANGUAGE FlexibleContexts #-}
module Language.Haskell.Liquid.Constraint.Qualifier
( qualifiers
, useSpcQuals
)
where
import Prelude hiding (error)
import Data.List (delete, nub)
import Data.Maybe (isJust, catMaybes, fromMaybe, isNothing)
import qualified Data.HashSet as S
import qualified Data.HashMap.Strict as M
import Debug.Trace (trace)
import TyCon
import Var (Var)
import Language.Fixpoint.Types hiding (mkQual)
import qualified Language.Fixpoint.Types.Config as FC
import Language.Fixpoint.SortCheck
import Language.Haskell.Liquid.Bare
import Language.Haskell.Liquid.Types.RefType
import Language.Haskell.Liquid.GHC.Misc (getSourcePos)
import Language.Haskell.Liquid.Misc (condNull)
import Language.Haskell.Liquid.Types.PredType
import Language.Haskell.Liquid.Types
--------------------------------------------------------------------------------
qualifiers :: GhcInfo -> SEnv Sort -> [Qualifier]
--------------------------------------------------------------------------------
qualifiers info lEnv
= condNull (useSpcQuals info) (gsQualifiers $ spec info)
++ condNull (useSigQuals info) (sigQualifiers info lEnv)
++ condNull (useAlsQuals info) (alsQualifiers info lEnv)
-- --------------------------------------------------------------------------------
-- qualifiers :: GhcInfo -> SEnv Sort -> [Qualifier]
-- --------------------------------------------------------------------------------
-- qualifiers info env = spcQs ++ genQs
-- where
-- spcQs = gsQualifiers spc
-- genQs = specificationQualifiers info env
-- n = maxParams (getConfig spc)
-- spc = spec info
maxQualParams :: (HasConfig t) => t -> Int
maxQualParams = maxParams . getConfig
-- | Use explicitly given qualifiers .spec or source (.hs, .lhs) files
useSpcQuals :: (HasConfig t) => t -> Bool
useSpcQuals i = useQuals i && not (useAlsQuals i)
-- | Scrape qualifiers from function signatures (incr :: x:Int -> {v:Int | v > x})
useSigQuals :: (HasConfig t) => t -> Bool
useSigQuals i = useQuals i && not (useAlsQuals i)
-- | Scrape qualifiers from refinement type aliases (type Nat = {v:Int | 0 <= 0})
useAlsQuals :: (HasConfig t) => t -> Bool
useAlsQuals i = useQuals i && i `hasOpt` higherOrderFlag
useQuals :: (HasConfig t) => t -> Bool
useQuals = not . (FC.All == ) . eliminate . getConfig
--------------------------------------------------------------------------------
alsQualifiers :: GhcInfo -> SEnv Sort -> [Qualifier]
--------------------------------------------------------------------------------
alsQualifiers info lEnv
= [ q | a <- specAliases info
, q <- refTypeQuals lEnv (rtPos a) tce (rtBody a)
, length (qParams q) <= k + 1
, validQual lEnv q
]
where
k = maxQualParams info
tce = gsTcEmbeds (spec info)
-- Symbol (RTAlias RTyVar SpecType)
specAliases :: GhcInfo -> [RTAlias RTyVar SpecType]
specAliases = M.elems . typeAliases . gsRTAliases . spec
validQual :: SEnv Sort -> Qualifier -> Bool
validQual lEnv q = isJust $ checkSortExpr env (qBody q)
where
env = unionSEnv lEnv qEnv
qEnv = M.fromList (qParams q)
--------------------------------------------------------------------------------
sigQualifiers :: GhcInfo -> SEnv Sort -> [Qualifier]
--------------------------------------------------------------------------------
sigQualifiers info lEnv
= [ q | (x, t) <- specBinders info
, x `S.member` qbs
, q <- refTypeQuals lEnv (getSourcePos x) tce (val t)
-- NOTE: large qualifiers are VERY expensive, so we only mine
-- qualifiers up to a given size, controlled with --max-params
, length (qParams q) <= k + 1
]
where
k = maxQualParams info
tce = gsTcEmbeds (spec info)
qbs = qualifyingBinders info
qualifyingBinders :: GhcInfo -> S.HashSet Var
qualifyingBinders info = S.difference sTake sDrop
where
sTake = S.fromList $ defVars info ++ scrapeVars info
sDrop = S.fromList $ specAxiomVars info
-- NOTE: this mines extra, useful qualifiers but causes
-- a significant increase in running time, so we hide it
-- behind `--scrape-imports` and `--scrape-used-imports`
scrapeVars :: GhcInfo -> [Var]
scrapeVars info
| info `hasOpt` scrapeUsedImports = useVars info
| info `hasOpt` scrapeImports = impVars info
| otherwise = []
specBinders :: GhcInfo -> [(Var, LocSpecType)]
specBinders info = mconcat
[ gsTySigs sp
, gsAsmSigs sp
, gsCtors sp
, if info `hasOpt` scrapeInternals then gsInSigs sp else []
]
where
sp = spec info
specAxiomVars :: GhcInfo -> [Var]
specAxiomVars = gsReflects . spec
-- GRAVEYARD: scraping quals from imports kills the system with too much crap
-- specificationQualifiers info = {- filter okQual -} qs
-- where
-- qs = concatMap refTypeQualifiers ts
-- refTypeQualifiers = refTypeQuals $ tcEmbeds spc
-- ts = val <$> t1s ++ t2s
-- t1s = [t | (x, t) <- tySigs spc, x `S.member` definedVars]
-- t2s = [] -- [t | (_, t) <- ctor spc ]
-- definedVars = S.fromList $ defVars info
-- spc = spec info
--
-- okQual = not . any isPred . map snd . q_params
-- where
-- isPred (FApp tc _) = tc == stringFTycon "Pred"
-- isPred _ = False
-- TODO: rewrite using foldReft'
--------------------------------------------------------------------------------
refTypeQuals :: SEnv Sort -> SourcePos -> TCEmb TyCon -> SpecType -> [Qualifier]
--------------------------------------------------------------------------------
refTypeQuals lEnv l tce t0 = go emptySEnv t0
where
scrape = refTopQuals lEnv l tce t0
add x t γ = insertSEnv x (rTypeSort tce t) γ
goBind x t γ t' = go (add x t γ) t'
go γ t@(RVar _ _) = scrape γ t
go γ (RAllT _ t) = go γ t
go γ (RAllP p t) = go (insertSEnv (pname p) (rTypeSort tce $ (pvarRType p :: RSort)) γ) t
go γ t@(RAppTy t1 t2 _) = go γ t1 ++ go γ t2 ++ scrape γ t
go γ (RFun x t t' _) = go γ t ++ goBind x t γ t'
go γ t@(RApp c ts rs _) = scrape γ t ++ concatMap (go γ') ts ++ goRefs c γ' rs
where γ' = add (rTypeValueVar t) t γ
go γ (RAllE x t t') = go γ t ++ goBind x t γ t'
go γ (REx x t t') = go γ t ++ goBind x t γ t'
go _ _ = []
goRefs c g rs = concat $ zipWith (goRef g) rs (rTyConPVs c)
goRef _ (RProp _ (RHole _)) _ = []
goRef g (RProp s t) _ = go (insertsSEnv g s) t
insertsSEnv = foldr (\(x, t) γ -> insertSEnv x (rTypeSort tce t) γ)
refTopQuals :: (PPrint t, Reftable t, SubsTy RTyVar RSort t, Reftable (RTProp RTyCon RTyVar (UReft t)))
=> SEnv Sort
-> SourcePos
-> TCEmb TyCon
-> RType RTyCon RTyVar r
-> SEnv Sort
-> RRType (UReft t)
-> [Qualifier]
refTopQuals lEnv l tce t0 γ t
= [ mkQ v so pa | let (RR so (Reft (v, ra))) = rTypeSortedReft tce t
, pa <- conjuncts ra
, not $ isHole pa
, not $ isGradual pa
, isNothing $ checkSorted (insertSEnv v so γ') pa
]
++
[ mkP s e | let (MkUReft _ (Pr ps) _) = fromMaybe (msg t) $ stripRTypeBase t
, p <- findPVar (ty_preds $ toRTypeRep t0) <$> ps
, (s, _, e) <- pargs p
]
where
mkQ = mkQual lEnv l t0 γ
mkP = mkPQual lEnv l tce t0 γ
msg t = panic Nothing $ "Qualifier.refTopQuals: no typebase" ++ showpp t
γ' = unionSEnv' γ lEnv
mkPQual :: (PPrint r, Reftable r, SubsTy RTyVar RSort r, Reftable (RTProp RTyCon RTyVar r))
=> SEnv Sort
-> SourcePos
-> TCEmb TyCon
-> t
-> SEnv Sort
-> RRType r
-> Expr
-> Qualifier
mkPQual lEnv l tce t0 γ t e = mkQual lEnv l t0 γ' v so pa
where
v = "vv"
so = rTypeSort tce t
γ' = insertSEnv v so γ
pa = PAtom Eq (EVar v) e
mkQual :: SEnv Sort
-> SourcePos
-> t
-> SEnv Sort
-> Symbol
-> Sort
-> Expr
-> Qualifier
mkQual lEnv l _ γ v so p = Q "Auto" ((v, so) : xts) p l
where
xs = delete v $ nub $ syms p
xts = catMaybes $ zipWith (envSort l lEnv γ) xs [0..]
envSort :: SourcePos -> SEnv Sort -> SEnv Sort -> Symbol -> Integer -> Maybe (Symbol, Sort)
envSort l lEnv tEnv x i
| Just t <- lookupSEnv x tEnv = Just (x, t)
| Just _ <- lookupSEnv x lEnv = Nothing
| otherwise = Just (x, ai)
where
ai = trace msg $ fObj $ Loc l l $ tempSymbol "LHTV" i
msg = "unknown symbol in qualifier: " ++ show x