{- |

Module : $Header$

Copyright : (c) Christian Maeder and Uni Bremen 2003

Licence : similar to LGPL, see HetCATS/LICENCE.txt or LIZENZ.txt

Maintainer : maeder@tzi.de

Stability : experimental

Portability : portable

type inference

-}

module HasCASL.TypeCheck where

import HasCASL.Unify

import HasCASL.AsUtils

import HasCASL.Merge

import HasCASL.VarDecl

import HasCASL.As

import HasCASL.Le

import HasCASL.MixAna

import HasCASL.MapTerm

import HasCASL.TypeAna

import HasCASL.Constrain

import HasCASL.MinType

import qualified Common.Lib.Map as Map

import qualified Common.Lib.Set as Set

import qualified Common.Lib.Rel as Rel

import Common.Id

import Common.Result

import Common.GlobalAnnotations

import Common.Lib.State

import Data.Maybe

substTerm :: Subst -> Term -> Term

substTerm s = mapTerm (id, subst s)

resolveTerm :: GlobalAnnos -> Maybe Type -> Term -> State Env (Maybe Term)

resolveTerm ga mt trm = do

mtrm <- resolve ga trm

case mtrm of

Nothing -> return Nothing

Just t -> typeCheck mt t

checkPattern :: GlobalAnnos -> Pattern -> State Env (Maybe Pattern)

checkPattern ga pat = do

mPat <- resolvePattern ga pat

case mPat of

Nothing -> return Nothing

Just p -> do

np <- anaPattern p

typeCheck Nothing np

instantiate :: TypeScheme -> State Env (Type, [Type], Constraints)

instantiate sc = do

(typ, inst) <- toEnvState $ freshInstList sc

return (typ, inst, Set.fromList $ map ( \ ty@(TypeName _ k _)

-> Kinding ty k) inst)

instOpInfo :: OpInfo -> State Env (Type, [Type], Constraints, OpInfo)

instOpInfo oi = do

(ty, inst, cs) <- instantiate $ opType oi

return (ty, inst, cs, oi)

lookupError :: Type -> [OpInfo] -> String

lookupError ty ois =

" with (maximal) type: " ++ showPretty ty "\n"

++ " known types:\n " ++

showSepList ("\n "++) (showPretty . opType) ois ""

checkList :: [Maybe Type] -> [Term]

-> State Env [(Subst, Constraints, [Type], [Term])]

checkList [] [] = return [(eps, noC, [], [])]

checkList (ty : rty) (trm : rt) = do

fts <- infer ty trm

combs <- mapM ( \ (sf, cs, tyf, tf) -> do

rts <- checkList (map (fmap (subst sf)) rty) rt

return $ map ( \ (sr, cr, tys, tts) ->

(compSubst sf sr,

substC sr cs `joinC` cr,

subst sr tyf : tys,

tf : tts)) rts) fts

return $ map ( \ (sr, cr, tys, tts) ->

(sr, cr, subst sr tys, map (substTerm sr) tts))

$ concat combs

checkList _ _ = error "checkList"

typeCheck :: Maybe Type -> Term -> State Env (Maybe Term)

typeCheck mt trm =

do alts1 <- infer mt trm

tm <- gets typeMap

combs <- mapM ( \ (s, cr, ty, tr) -> do

Result ds mc <- toEnvState $ preClose tm cr

addDiags $ map (improveDiag tr) ds

return $ case mc of

Nothing -> []

Just (cs, cc) -> let

s1 = compSubst s cs

ms = monoSubsts tm (foldr (uncurry Rel.insert)

(fromTypeMap tm)

$ toListC cc) (subst s1 ty)

s2 = compSubst s1 ms

in [(s2, substC ms cc, subst s2 ty,

substTerm s2 tr)]) alts1

let alts = concat combs

let p = getMyPos trm

if null alts then

do addDiags [mkDiag Error "no typing for" trm]

return Nothing

else if null $ tail alts then do

let (_, cs, ty, t) = head alts

(ds, rcs) = simplify tm cs

es = map ( \ d -> d {diagKind = Hint, diagPos = p}) ds

addDiags es

if Set.isEmpty rcs then return ()

else addDiags [(mkDiag Error ("in term'"

++ showPretty t "' of type '"

++ showPretty ty "'\n unresolved constraints")

rcs){diagPos = p}]

return $ Just t

else let alts3 = filter ( \ (_, cs, _, _) ->

Set.isEmpty $ snd $ simplify tm cs) alts

falts = typeNub tm q2p alts3 in

if null falts then do

addDiags [mkDiag Error "no constraint resolution for" trm]

addDiags $ map (\ (_, cs, _, _) -> (mkDiag Hint

"simplification failed for" cs){diagPos = p}) alts

return Nothing

else if null $ tail falts then

let (_, _, _, t) = head falts in

return $ Just t

else

do addDiags [Diag Error

("ambiguous typings \n " ++

showSepList ("\n " ++)

( \ (n, t) -> shows n . (". " ++) . showPretty t)

(zip [1..(5::Int)] $ map ( \ (_,_,_,t) ->

t) falts) "")

p]

return Nothing

freshTypeVar :: Pos -> State Env Type

freshTypeVar p =

do (var, c) <- toEnvState $ freshVar p

return $ TypeName var star c

freshVars :: [Term] -> State Env [Type]

freshVars l = mapM (freshTypeVar . posOfTerm) l

inferAppl :: [Pos] -> Maybe Type -> Term -> Term

-> State Env [(Subst, Constraints, Type, Term)]

inferAppl ps mt t1 t2 = do

let origAppl = ApplTerm t1 t2 ps

tm <- gets typeMap

aty <- freshTypeVar $ posOfTerm t2

rty <- case mt of

Nothing -> freshTypeVar $ posOfTerm t1

Just ty -> return ty

ops <- infer (Just $ FunType aty PFunArr rty []) t1

combs <- mapM ( \ (sf, cf, _, tf) -> do

let sfty = subst sf aty

args <- infer (Just sfty) t2

-- args2 <- infer (Just $ FunType logicalType

-- PFunArr sfty ps) t2

-- let args = typeNub tm q2p (args1 ++ args2)

combs2 <- mapM ( \ (sa, ca, _, ta) -> do

let sr = compSubst sf sa

cr = joinC ca $ substC sa cf

Result ds mc <- toEnvState $ preClose tm cr

addDiags $ map (improveDiag origAppl) ds

return $ case mc of

Nothing -> []

Just (cs, cc) -> let sall = compSubst sr cs in

[(sall, cc, subst sall rty,

ApplTerm tf ta ps)]) args

return $ concat combs2) ops

let res = concat combs

if null res then

addDiags [case mt of

Nothing -> mkDiag Error

"untypable application" origAppl

Just ty -> mkDiag Hint

("untypable application (with result type: "

++ showPretty ty ")\n")

origAppl]

else return ()

return res

-- True means possibly find a smaller type

infer :: Maybe Type -> Term

-> State Env [(Subst, Constraints, Type, Term)]

infer mt trm = do

tm <- gets typeMap

let mUnify = mgu tm mt . Just

uniDiags = addDiags . map (improveDiag trm)

as <- gets assumps

vs <- gets localVars

case trm of

qv@(QualVar (VarDecl v t qs ps)) -> do

case mt of

Nothing -> return [(eps, noC, t, qv)]

Just ty -> do

Result ds mc <- toEnvState $ preClose tm

$ insertC (Subtyping t ty) noC

addDiags $ map (improveDiag v) ds

return $ case mc of

Nothing -> []

Just (s, cc) -> let nty = subst s t in

[(s, cc, nty,

QualVar $ VarDecl v nty qs ps)]

QualOp br (InstOpId i ts qs) sc ps -> do

(ty, inst, cs) <- instantiate sc

let Result ds ms = mgu tm (if null ts then inst else ts) inst

uniDiags ds

return $ case ms of

Nothing -> []

Just s -> let q@(_, ncs, nTy, qv) =

(s, substC s cs, subst s ty,

QualOp br (InstOpId i (map (subst s) inst)

qs) sc ps) in case mt of

Nothing -> [q]

Just inTy -> [(s, insertC (Subtyping nTy $ subst s inTy)

ncs, nTy, qv)]

ResolvedMixTerm i ts ps ->

if null ts then do

let ois = case Map.lookup i vs of

Nothing -> opInfos $ Map.findWithDefault

(OpInfos []) i as

Just t -> [OpInfo (simpleTypeScheme t) [] VarDefn]

insts <- mapM instOpInfo ois

ls <- case mt of

Nothing -> return $ map ( \ (ty, is, cs, oi)

-> (eps, ty, is, cs, oi)) insts

Just inTy -> do

combs <- mapM ( \ (ty, is, cs, oi) -> do

Result ds mc <- toEnvState $ preClose tm

$ insertC (Subtyping ty inTy) cs

addDiags $ map (improveDiag i) ds

return $ case mc of

Nothing -> []

Just (s, cc) -> [(s, subst s ty

, map (subst s) is

, cc, oi)]) insts

let rs = concat combs

if null rs then

addDiags [Diag Hint

("no type match for: " ++ showId i "\n"

++ lookupError inTy ois)

(posOfId i) ]

else return ()

return rs

return $ typeNub tm q2p $

map ( \ (s, ty, is, cs, oi) ->

case opDefn oi of

VarDefn -> (s, cs, ty, QualVar $

VarDecl i ty Other ps)

x -> let br = case x of

NoOpDefn v -> v

Definition v _ -> v

_ -> Op in

(s, cs, ty,

QualOp br (InstOpId i is [])

(opType oi) ps)) ls

else inferAppl ps mt (ResolvedMixTerm i [] ps)

$ mkTupleTerm ts ps

ApplTerm t1 t2 ps -> inferAppl ps mt t1 t2

TupleTerm ts ps ->

case mt of

Nothing -> do

ls <- checkList (map (const Nothing) ts) ts

return $ map ( \ (su, cs, tys, trms) ->

(su, cs, mkProductType tys ps,

mkTupleTerm trms ps)) ls

Just ty -> do

tvs <- freshVars ts

let pt = mkProductType tvs []

Result ds ms = mgu tm ty pt

uniDiags ds

case ms of

Nothing -> return []

Just s -> do

ls <- checkList (map (Just . subst s) tvs) ts

return $ map ( \ (su, cs, tys, trms) ->

(compSubst s su, substC s cs,

mkProductType tys ps,

mkTupleTerm trms ps)) ls

TypedTerm t qual ty ps -> do

case qual of

OfType -> do

let Result ds ms = mUnify ty

uniDiags ds

case ms of

Nothing -> if lesserType tm ty $ fromJust mt then do

rs <- infer (Just ty) t

return $ map ( \ (s2, cs, typ, tr) ->

(s2, cs, typ, TypedTerm tr qual ty ps)) rs

else return []

Just s -> do

rs <- infer (Just $ subst s ty) t

return $ map ( \ (s2, cs, typ, tr) ->

(compSubst s s2, substC s cs, typ,

TypedTerm tr qual ty ps)) rs

InType -> do

let Result ds ms = mUnify logicalType

uniDiags ds

case ms of

Nothing -> return []

Just s -> do

rs <- infer Nothing t

return $ map ( \ (s2, cs, typ, tr) ->

(compSubst s s2,

substC s $ insertC (Subtyping ty typ) cs,

logicalType,

TypedTerm tr qual ty ps)) rs

AsType -> do

let Result ds ms = mUnify ty

uniDiags ds

case ms of

Nothing -> return []

Just s -> do

rs <- infer Nothing t

combs <- mapM ( \ (s2, cs, typ, tr) -> do

let s1 = compSubst s s2

Result es mc <- toEnvState $ preClose tm

$ insertC (Subtyping ty typ) cs

addDiags $ map (improveDiag trm) es

return $ case mc of

Nothing -> []

Just (s3, cc) ->

[(compSubst s1 s3, cc,

subst s3 typ,

TypedTerm tr qual ty ps)]) rs

return $ concat combs

QuantifiedTerm quant decls t ps -> do

mapM_ addGenLocalVar decls

let Result ds ms = mUnify logicalType

uniDiags ds

case ms of

Nothing -> return []

Just _ -> do

rs <- infer (Just logicalType) t

putLocalVars vs

putTypeMap tm

return $ map ( \ (s, cs, typ, tr) ->

(s, cs, typ, QuantifiedTerm quant decls tr ps)) rs

LambdaTerm pats part resTrm ps -> do

pvs <- freshVars pats

rty <- freshTypeVar $ posOfTerm resTrm

let fty l = if null l then rty else

FunType (head l) (case part of

Partial -> PFunArr

Total -> FunArr) (fty $ tail l) []

myty = fty pvs

Result ds ms = mUnify myty

uniDiags ds

case ms of

Nothing -> return []

Just s -> do

ls <- checkList (map (Just . subst s) pvs) pats

rs <- mapM ( \ ( s2, cs, _, nps) -> do

mapM_ addLocalVar $ concatMap extractVars nps

let newS = compSubst s s2

es <- infer (Just $ subst newS rty) resTrm

putLocalVars vs

return $ map ( \ (s3, cr, _, rtm) ->

(compSubst newS s3,

substC s3 cs `joinC` cr,

subst s3 (subst newS myty),

LambdaTerm nps part rtm ps)) es) ls

return $ concat rs

CaseTerm ofTrm eqs ps -> do

ts <- infer Nothing ofTrm

rty <- case mt of

Nothing -> freshTypeVar $ posOfTerm trm

Just ty -> return ty

if null ts then addDiags [mkDiag Error

"unresolved of-term in case" ofTrm]

else return ()

rs <- mapM ( \ (s1, cs, oty, otrm) -> do

es <- inferCaseEqs oty (subst s1 rty) eqs

return $ map ( \ (s2, cr, _, ty, nes) ->

(compSubst s1 s2,

substC s2 cs `joinC` cr, ty,

CaseTerm otrm nes ps)) es) ts

return $ concat rs

LetTerm br eqs inTrm ps -> do

es <- inferLetEqs eqs

rs <- mapM ( \ (s1, cs, _, nes) -> do

mapM_ addLocalVar $ concatMap (\ (ProgEq p _ _) ->

extractVars p) nes

ts <- infer mt inTrm

return $ map ( \ (s2, cr, ty, nt) ->

(compSubst s1 s2,

substC s2 cs `joinC` cr,

ty,

LetTerm br nes nt ps)) ts) es

putLocalVars vs

return $ concat rs

AsPattern (VarDecl v _ ok qs) pat ps -> do

pats <- infer mt pat

return $ map ( \ (s1, cs, t1, p1) -> (s1, cs, t1,

AsPattern (VarDecl v t1 ok qs) p1 ps)) pats

_ -> do ty <- freshTypeVar $ posOfTerm trm

addDiags [mkDiag Error "unexpected term" trm]

return [(eps, noC, ty, trm)]

inferLetEqs :: [ProgEq] -> State Env [(Subst, Constraints, [Type], [ProgEq])]

inferLetEqs es = do

let pats = map (\ (ProgEq p _ _) -> p) es

trms = map (\ (ProgEq _ t _) -> t) es

qs = map (\ (ProgEq _ _ q) -> q) es

do vs <- gets localVars

newPats <- checkList (map (const Nothing) pats) pats

combs <- mapM ( \ (sf, pcs, tys, pps) -> do

mapM_ addLocalVar $ concatMap extractVars pps

newTrms <- checkList (map Just tys) trms

return $ map ( \ (sr, tcs, tys2, tts ) ->

(compSubst sf sr,

joinC tcs $ substC sr pcs, tys2,

zipWith3 ( \ p t q -> ProgEq (substTerm sr p) t q)

pps tts qs)) newTrms) newPats

putLocalVars vs

return $ concat combs

inferCaseEq :: Type -> Type -> ProgEq

-> State Env [(Subst, Constraints, Type, Type, ProgEq)]

inferCaseEq pty tty (ProgEq pat trm ps) = do

as <- gets assumps

let newAs = filterAssumps ( \ o -> case opDefn o of

ConstructData _ -> True

VarDefn -> True

_ -> False) as

putAssumps newAs

pats <- infer (Just pty) pat

putAssumps as

if null pats then addDiags [mkDiag Error "unresolved case pattern" pat]

else return ()

vs <- gets localVars

es <- mapM ( \ (s, cs, ty, p) -> do

mapM_ addLocalVar $ extractVars p

ts <- infer (Just $ subst s tty) trm

putLocalVars vs

return $ map ( \ (st, cr, tyt, t) ->

(compSubst s st,

substC st cs `joinC` cr,

subst st ty, tyt,

ProgEq p t ps)) ts) pats

return $ concat es

inferCaseEqs :: Type -> Type -> [ProgEq]

-> State Env [(Subst, Constraints, Type, Type, [ProgEq])]

inferCaseEqs pty tTy [] = return [(eps, noC, pty, tTy, [])]

inferCaseEqs pty tty (eq:eqs) = do

fts <- inferCaseEq pty tty eq

rs <- mapM (\ (_, cs, pty1, tty1, ne) -> do

rts <- inferCaseEqs pty1 tty1 eqs

return $ map ( \ (s2, cr, pty2, tty2, nes) ->

(s2,

substC s2 cs `joinC` cr,

pty2, tty2, ne:nes)) rts) fts

return $ concat rs