#include "HsVersions.h"
import BasicTypes
-import Type
+import Id ( evVarPred )
+import TcErrors
import TcRnTypes
import FunDeps
import qualified TcMType as TcM
import TcType
-import TcErrors
+import Type
import Coercion
import Class
import TyCon
-- We can tell if ty' is function-free by
-- whether there are any floated constraints
; if isEmptyCCan ccs then
- return (ty, ty, emptyCCan)
+ return (ty, mkReflCo ty, emptyCCan)
else
return (xi, co, ccs) }
flatten _ v@(TyVarTy _)
- = return (v, v, emptyCCan)
+ = return (v, mkReflCo v, emptyCCan)
flatten ctxt (AppTy ty1 ty2)
= do { (xi1,co1,c1) <- flatten ctxt ty1
; (xi2,co2,c2) <- flatten ctxt ty2
- ; return (mkAppTy xi1 xi2, mkAppCoercion co1 co2, c1 `andCCan` c2) }
+ ; return (mkAppTy xi1 xi2, mkAppCo co1 co2, c1 `andCCan` c2) }
flatten ctxt (FunTy ty1 ty2)
= do { (xi1,co1,c1) <- flatten ctxt ty1
; (xi2,co2,c2) <- flatten ctxt ty2
- ; return (mkFunTy xi1 xi2, mkFunCoercion co1 co2, c1 `andCCan` c2) }
+ ; return (mkFunTy xi1 xi2, mkFunCo co1 co2, c1 `andCCan` c2) }
flatten fl (TyConApp tc tys)
-- For a normal type constructor or data family application, we just
-- recursively flatten the arguments.
| not (isSynFamilyTyCon tc)
= do { (xis,cos,ccs) <- flattenMany fl tys
- ; return (mkTyConApp tc xis, mkTyConCoercion tc cos, ccs) }
+ ; return (mkTyConApp tc xis, mkTyConAppCo tc cos, ccs) }
-- Otherwise, it's a type function application, and we have to
-- flatten it away as well, and generate a new given equality constraint
-- in which case the remaining arguments should
-- be dealt with by AppTys
fam_ty = mkTyConApp tc xi_args
- fam_co = fam_ty -- identity
+ fam_co = mkReflCo fam_ty -- identity
; (ret_co, rhs_var, ct) <-
if isGiven fl then
, cc_fun = tc
, cc_tyargs = xi_args
, cc_rhs = rhs_var }
- ; return $ (mkCoVarCoercion cv, rhs_var, ct) }
+ ; return $ (mkCoVarCo cv, rhs_var, ct) }
else -- Derived or Wanted: make a new *unification* flatten variable
do { rhs_var <- newFlexiTcSTy (typeKind fam_ty)
; cv <- newCoVar fam_ty rhs_var
, cc_fun = tc
, cc_tyargs = xi_args
, cc_rhs = rhs_var }
- ; return $ (mkCoVarCoercion cv, rhs_var, ct) }
+ ; return $ (mkCoVarCo cv, rhs_var, ct) }
; return ( foldl AppTy rhs_var xi_rest
- , foldl AppTy (mkSymCoercion ret_co
- `mkTransCoercion` mkTyConCoercion tc cos_args) cos_rest
+ , foldl mkAppCo
+ (mkSymCo ret_co
+ `mkTransCo` mkTyConAppCo tc cos_args)
+ cos_rest
, ccs `extendCCans` ct) }
tv_set = mkVarSet tvs
; unless (isEmptyBag bad_eqs)
(flattenForAllErrorTcS ctxt ty bad_eqs)
- ; return (mkForAllTys tvs rho', mkForAllTys tvs co, ccs) }
+ ; return (mkForAllTys tvs rho', foldr mkForAllCo co tvs, ccs) }
---------------
flattenPred :: CtFlavor -> TcPredType -> TcS (TcPredType, Coercion, CanonicalCts)
flattenPred ctxt (ClassP cls tys)
= do { (tys', cos, ccs) <- flattenMany ctxt tys
- ; return (ClassP cls tys', mkClassPPredCo cls cos, ccs) }
+ ; return (ClassP cls tys', mkPredCo $ ClassP cls cos, ccs) }
flattenPred ctxt (IParam nm ty)
= do { (ty', co, ccs) <- flatten ctxt ty
- ; return (IParam nm ty', mkIParamPredCo nm co, ccs) }
--- TODO: Handling of coercions between EqPreds must be revisited once the New Coercion API is ready!
+ ; return (IParam nm ty', mkPredCo $ IParam nm co, ccs) }
flattenPred ctxt (EqPred ty1 ty2)
= do { (ty1', co1, ccs1) <- flatten ctxt ty1
; (ty2', co2, ccs2) <- flatten ctxt ty2
- ; return (EqPred ty1' ty2', mkEqPredCo co1 co2, ccs1 `andCCan` ccs2) }
-
+ ; return (EqPred ty1' ty2', mkPredCo $ EqPred co1 co2, ccs1 `andCCan` ccs2) }
\end{code}
%************************************************************************
canClassToWorkList fl v cn tys
= do { (xis,cos,ccs) <- flattenMany fl tys -- cos :: xis ~ tys
; let no_flattening_happened = isEmptyCCan ccs
- dict_co = mkTyConCoercion (classTyCon cn) cos
+ dict_co = mkTyConAppCo (classTyCon cn) cos
; v_new <- if no_flattening_happened then return v
else if isGiven fl then return v
-- The cos are all identities if fl=Given,
-- hence nothing to do
else do { v' <- newDictVar cn xis -- D xis
; when (isWanted fl) $ setDictBind v (EvCast v' dict_co)
- ; when (isGiven fl) $ setDictBind v' (EvCast v (mkSymCoercion dict_co))
+ ; when (isGiven fl) $ setDictBind v' (EvCast v (mkSymCo dict_co))
-- NB: No more setting evidence for derived now
; return v' }
canEq :: CtFlavor -> EvVar -> Type -> Type -> TcS CanonicalCts
canEq fl cv ty1 ty2
- | tcEqType ty1 ty2 -- Dealing with equality here avoids
+ | eqType ty1 ty2 -- Dealing with equality here avoids
-- later spurious occurs checks for a~a
- = do { when (isWanted fl) (setCoBind cv ty1)
+ = do { when (isWanted fl) (setCoBind cv (mkReflCo ty1))
; return emptyCCan }
-- If one side is a variable, orient and flatten,
; canEqLeaf untch fl cv (classify ty1) (classify ty2) }
-- NB: don't use VarCls directly because tv1 or tv2 may be scolems!
-canEq fl cv (TyConApp fn tys) ty2
- | isSynFamilyTyCon fn, length tys == tyConArity fn
- = do { untch <- getUntouchables
- ; canEqLeaf untch fl cv (FunCls fn tys) (classify ty2) }
-canEq fl cv ty1 (TyConApp fn tys)
- | isSynFamilyTyCon fn, length tys == tyConArity fn
- = do { untch <- getUntouchables
- ; canEqLeaf untch fl cv (classify ty1) (FunCls fn tys) }
-
-canEq fl cv s1 s2
- | Just (t1a,t1b,t1c) <- splitCoPredTy_maybe s1,
- Just (t2a,t2b,t2c) <- splitCoPredTy_maybe s2
- = do { (v1,v2,v3)
- <- if isWanted fl then -- Wanted
- do { v1 <- newCoVar t1a t2a
- ; v2 <- newCoVar t1b t2b
- ; v3 <- newCoVar t1c t2c
- ; let res_co = mkCoPredCo (mkCoVarCoercion v1)
- (mkCoVarCoercion v2) (mkCoVarCoercion v3)
- ; setCoBind cv res_co
- ; return (v1,v2,v3) }
- else if isGiven fl then -- Given
- let co_orig = mkCoVarCoercion cv
- coa = mkCsel1Coercion co_orig
- cob = mkCsel2Coercion co_orig
- coc = mkCselRCoercion co_orig
- in do { v1 <- newGivenCoVar t1a t2a coa
- ; v2 <- newGivenCoVar t1b t2b cob
- ; v3 <- newGivenCoVar t1c t2c coc
- ; return (v1,v2,v3) }
- else -- Derived
- do { v1 <- newDerivedId (EqPred t1a t2a)
- ; v2 <- newDerivedId (EqPred t1b t2b)
- ; v3 <- newDerivedId (EqPred t1c t2c)
- ; return (v1,v2,v3) }
- ; cc1 <- canEq fl v1 t1a t2a
- ; cc2 <- canEq fl v2 t1b t2b
- ; cc3 <- canEq fl v3 t1c t2c
- ; return (cc1 `andCCan` cc2 `andCCan` cc3) }
-
-
-- Split up an equality between function types into two equalities.
canEq fl cv (FunTy s1 t1) (FunTy s2 t2)
= do { (argv, resv) <-
do { argv <- newCoVar s1 s2
; resv <- newCoVar t1 t2
; setCoBind cv $
- mkFunCoercion (mkCoVarCoercion argv) (mkCoVarCoercion resv)
+ mkFunCo (mkCoVarCo argv) (mkCoVarCo resv)
; return (argv,resv) }
else if isGiven fl then
- let [arg,res] = decomposeCo 2 (mkCoVarCoercion cv)
+ let [arg,res] = decomposeCo 2 (mkCoVarCo cv)
in do { argv <- newGivenCoVar s1 s2 arg
; resv <- newGivenCoVar t1 t2 res
; return (argv,resv) }
; cc2 <- canEq fl resv t1 t2
; return (cc1 `andCCan` cc2) }
-canEq fl cv (PredTy (IParam n1 t1)) (PredTy (IParam n2 t2))
- | n1 == n2
- = if isWanted fl then
- do { v <- newCoVar t1 t2
- ; setCoBind cv $ mkIParamPredCo n1 (mkCoVarCoercion cv)
- ; canEq fl v t1 t2 }
- else return emptyCCan -- DV: How to decompose given IP coercions?
-
-canEq fl cv (PredTy (ClassP c1 tys1)) (PredTy (ClassP c2 tys2))
- | c1 == c2
- = if isWanted fl then
- do { vs <- zipWithM newCoVar tys1 tys2
- ; setCoBind cv $ mkClassPPredCo c1 (map mkCoVarCoercion vs)
- ; andCCans <$> zipWith3M (canEq fl) vs tys1 tys2
- }
- else return emptyCCan
- -- How to decompose given dictionary (and implicit parameter) coercions?
- -- You may think that the following is right:
- -- let cos = decomposeCo (length tys1) (mkCoVarCoercion cv)
- -- in zipWith3M newGivOrDerCoVar tys1 tys2 cos
- -- But this assumes that the coercion is a type constructor-based
- -- coercion, and not a PredTy (ClassP cn cos) coercion. So we chose
- -- to not decompose these coercions. We have to get back to this
- -- when we clean up the Coercion API.
+canEq fl cv (TyConApp fn tys) ty2
+ | isSynFamilyTyCon fn, length tys == tyConArity fn
+ = do { untch <- getUntouchables
+ ; canEqLeaf untch fl cv (FunCls fn tys) (classify ty2) }
+canEq fl cv ty1 (TyConApp fn tys)
+ | isSynFamilyTyCon fn, length tys == tyConArity fn
+ = do { untch <- getUntouchables
+ ; canEqLeaf untch fl cv (classify ty1) (FunCls fn tys) }
canEq fl cv (TyConApp tc1 tys1) (TyConApp tc2 tys2)
- | isAlgTyCon tc1 && isAlgTyCon tc2
+ | isDecomposableTyCon tc1 && isDecomposableTyCon tc2
, tc1 == tc2
, length tys1 == length tys2
= -- Generate equalities for each of the corresponding arguments
<- if isWanted fl then
do { argsv <- zipWithM newCoVar tys1 tys2
; setCoBind cv $
- mkTyConCoercion tc1 (map mkCoVarCoercion argsv)
+ mkTyConAppCo tc1 (map mkCoVarCo argsv)
; return argsv }
else if isGiven fl then
- let cos = decomposeCo (length tys1) (mkCoVarCoercion cv)
+ let cos = decomposeCo (length tys1) (mkCoVarCo cv)
in zipWith3M newGivenCoVar tys1 tys2 cos
else -- Derived
canEq fl cv ty1 ty2
| Just (s1,t1) <- tcSplitAppTy_maybe ty1
, Just (s2,t2) <- tcSplitAppTy_maybe ty2
- = do { (cv1,cv2) <-
- if isWanted fl
- then do { cv1 <- newCoVar s1 s2
- ; cv2 <- newCoVar t1 t2
- ; setCoBind cv $
- mkAppCoercion (mkCoVarCoercion cv1) (mkCoVarCoercion cv2)
- ; return (cv1,cv2) }
-
- else if isGiven fl then
- let co1 = mkLeftCoercion $ mkCoVarCoercion cv
- co2 = mkRightCoercion $ mkCoVarCoercion cv
- in do { cv1 <- newGivenCoVar s1 s2 co1
- ; cv2 <- newGivenCoVar t1 t2 co2
- ; return (cv1,cv2) }
- else -- Derived
- do { cv1 <- newDerivedId (EqPred s1 s2)
- ; cv2 <- newDerivedId (EqPred t1 t2)
- ; return (cv1,cv2) }
-
- ; cc1 <- canEq fl cv1 s1 s2
- ; cc2 <- canEq fl cv2 t1 t2
- ; return (cc1 `andCCan` cc2) }
+ = if isWanted fl
+ then do { cv1 <- newCoVar s1 s2
+ ; cv2 <- newCoVar t1 t2
+ ; setCoBind cv $
+ mkAppCo (mkCoVarCo cv1) (mkCoVarCo cv2)
+ ; cc1 <- canEq fl cv1 s1 s2
+ ; cc2 <- canEq fl cv2 t1 t2
+ ; return (cc1 `andCCan` cc2) }
+
+ else if isDerived fl
+ then do { cv1 <- newDerivedId (EqPred s1 s2)
+ ; cv2 <- newDerivedId (EqPred t1 t2)
+ ; cc1 <- canEq fl cv1 s1 s2
+ ; cc2 <- canEq fl cv2 t1 t2
+ ; return (cc1 `andCCan` cc2) }
+
+ else return emptyCCan -- We cannot decompose given applications
+ -- because we no longer have 'left' and 'right'
canEq fl cv s1@(ForAllTy {}) s2@(ForAllTy {})
| tcIsForAllTy s1, tcIsForAllTy s2,
| cls1 `re_orient` cls2
= do { cv' <- if isWanted fl
then do { cv' <- newCoVar s2 s1
- ; setCoBind cv $ mkSymCoercion (mkCoVarCoercion cv')
+ ; setCoBind cv $ mkSymCo (mkCoVarCo cv')
; return cv' }
else if isGiven fl then
- newGivenCoVar s2 s1 (mkSymCoercion (mkCoVarCoercion cv))
+ newGivenCoVar s2 s1 (mkSymCo (mkCoVarCo cv))
else -- Derived
newDerivedId (EqPred s2 s1)
; canEqLeafOriented fl cv' cls2 s1 }
do { cv' <- newCoVar (unClassify (FunCls fn xis1)) xi2
-- cv' : F xis ~ xi2
; let -- fun_co :: F xis1 ~ F tys1
- fun_co = mkTyConCoercion fn cos1
+ fun_co = mkTyConAppCo fn cos1
-- want_co :: F tys1 ~ s2
- want_co = mkSymCoercion fun_co
- `mkTransCoercion` mkCoVarCoercion cv'
- `mkTransCoercion` co2
+ want_co = mkSymCo fun_co
+ `mkTransCo` mkCoVarCo cv'
+ `mkTransCo` co2
; setCoBind cv want_co
; return cv' }
else -- Derived
else if isGiven fl then return cv
else if isWanted fl then
do { cv' <- newCoVar (mkTyVarTy tv) xi2' -- cv' : tv ~ xi2
- ; setCoBind cv (mkCoVarCoercion cv' `mkTransCoercion` co)
+ ; setCoBind cv (mkCoVarCo cv' `mkTransCo` co)
; return cv' }
else -- Derived
newDerivedId (EqPred (mkTyVarTy tv) xi2')
expandAway tv ty@(ForAllTy {})
= let (tvs,rho) = splitForAllTys ty
tvs_knds = map tyVarKind tvs
- in if tv `elemVarSet` tyVarsOfTypes tvs_knds then
+ in if tv `elemVarSet` tyVarsOfTypes tvs_knds then
-- Can't expand away the kinds unless we create
-- fresh variables which we don't want to do at this point.
Nothing
push_ctx loc = pushErrCtxt FunDepOrigin (False, mkEqnMsg d1 d2) loc
do_one subst (FDEq { fd_pos = i, fd_ty_left = ty1, fd_ty_right = ty2 })
- = do { let sty1 = substTy subst ty1
- sty2 = substTy subst ty2
+ = do { let sty1 = Type.substTy subst ty1
+ sty2 = Type.substTy subst ty2
; ev <- newCoVar sty1 sty2
; return (i, mkEvVarX ev fl') }
where
do_one :: Type -> Int -> (Type,Coercion)
do_one ty n = case lookup n param_eqs of
- Just wev -> (get_fst_ty wev, mkCoVarCoercion (evVarOf wev))
- Nothing -> (ty,ty) -- Identity
+ Just wev -> (get_fst_ty wev, mkCoVarCo (evVarOf wev))
+ Nothing -> (ty, mkReflCo ty) -- Identity
get_fst_ty wev = case evVarOfPred wev of
EqPred ty1 _ -> ty1
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