A ``lint'' pass to check for Core correctness
\begin{code}
-module CoreLint (
- lintCoreBindings,
- lintUnfolding,
- showPass, endPass, endPassIf, endIteration
- ) where
+module CoreLint ( lintCoreBindings, lintUnfolding ) where
#include "HsVersions.h"
-import NewDemand
+import Demand
import CoreSyn
import CoreFVs
import CoreUtils
import ErrUtils
import SrcLoc
import Type
+import TypeRep
import Coercion
import TyCon
+import Class
import BasicTypes
import StaticFlags
import ListSetOps
-import DynFlags
+import PrelNames
import Outputable
import FastString
import Util
+import Control.Monad
import Data.Maybe
\end{code}
%************************************************************************
%* *
-\subsection{End pass}
-%* *
-%************************************************************************
-
-@showPass@ and @endPass@ don't really belong here, but it makes a convenient
-place for them. They print out stuff before and after core passes,
-and do Core Lint when necessary.
-
-\begin{code}
-endPass :: DynFlags -> String -> DynFlag -> [CoreBind] -> IO [CoreBind]
-endPass = dumpAndLint dumpIfSet_core
-
-endPassIf :: Bool -> DynFlags -> String -> DynFlag -> [CoreBind] -> IO [CoreBind]
-endPassIf cond = dumpAndLint (dumpIf_core cond)
-
-endIteration :: DynFlags -> String -> DynFlag -> [CoreBind] -> IO [CoreBind]
-endIteration = dumpAndLint dumpIfSet_dyn
-
-dumpAndLint :: (DynFlags -> DynFlag -> String -> SDoc -> IO ())
- -> DynFlags -> String -> DynFlag -> [CoreBind] -> IO [CoreBind]
-dumpAndLint dump dflags pass_name dump_flag binds
- = do
- -- Report result size if required
- -- This has the side effect of forcing the intermediate to be evaluated
- debugTraceMsg dflags 2 $
- (text " Result size =" <+> int (coreBindsSize binds))
-
- -- Report verbosely, if required
- dump dflags dump_flag pass_name (pprCoreBindings binds)
-
- -- Type check
- lintCoreBindings dflags pass_name binds
-
- return binds
-\end{code}
-
-
-%************************************************************************
-%* *
\subsection[lintCoreBindings]{@lintCoreBindings@: Top-level interface}
%* *
%************************************************************************
-- may well be happening...);
-Note [Type lets]
-~~~~~~~~~~~~~~~~
+Note [Linting type lets]
+~~~~~~~~~~~~~~~~~~~~~~~~
In the desugarer, it's very very convenient to be able to say (in effect)
- let a = Int in <body>
-That is, use a type let. (See notes just below for why we want this.)
-
-We don't have type lets in Core, so the desugarer uses type lambda
- (/\a. <body>) Int
-However, in the lambda form, we'd get lint errors from:
- (/\a. let x::a = 4 in <body>) Int
-because (x::a) doesn't look compatible with (4::Int).
-
-So (HACK ALERT) the Lint phase does type-beta reduction "on the fly",
-as it were. It carries a type substitution (in this example [a -> Int])
-and applies this substitution before comparing types. The functin
- lintTy :: Type -> LintM Type
+ let a = Type Int in <body>
+That is, use a type let. See Note [Type let] in CoreSyn.
+
+However, when linting <body> we need to remember that a=Int, else we might
+reject a correct program. So we carry a type substitution (in this example
+[a -> Int]) and apply this substitution before comparing types. The functin
+ lintInTy :: Type -> LintM Type
returns a substituted type; that's the only reason it returns anything.
When we encounter a binder (like x::a) we must apply the substitution
find an occurence of an Id, we fetch it from the in-scope set.
-Why we need type let
-~~~~~~~~~~~~~~~~~~~~
-It's needed when dealing with desugarer output for GADTs. Consider
- data T = forall a. T a (a->Int) Bool
- f :: T -> ... ->
- f (T x f True) = <e1>
- f (T y g False) = <e2>
-After desugaring we get
- f t b = case t of
- T a (x::a) (f::a->Int) (b:Bool) ->
- case b of
- True -> <e1>
- False -> (/\b. let y=x; g=f in <e2>) a
-And for a reason I now forget, the ...<e2>... can mention a; so
-we want Lint to know that b=a. Ugh.
-
-I tried quite hard to make the necessity for this go away, by changing the
-desugarer, but the fundamental problem is this:
-
- T a (x::a) (y::Int) -> let fail::a = ...
- in (/\b. ...(case ... of
- True -> x::b
- False -> fail)
- ) a
-Now the inner case look as though it has incompatible branches.
-
-
\begin{code}
-lintCoreBindings :: DynFlags -> String -> [CoreBind] -> IO ()
-
-lintCoreBindings dflags _whoDunnit _binds
- | not (dopt Opt_DoCoreLinting dflags)
- = return ()
-
-lintCoreBindings dflags whoDunnit binds
- = case (initL (lint_binds binds)) of
- Nothing -> showPass dflags ("Core Linted result of " ++ whoDunnit)
- Just bad_news -> printDump (display bad_news) >>
- ghcExit dflags 1
+lintCoreBindings :: [CoreBind] -> (Bag Message, Bag Message)
+-- Returns (warnings, errors)
+lintCoreBindings binds
+ = initL (lint_binds binds)
where
-- Put all the top-level binders in scope at the start
-- This is because transformation rules can bring something
lint_bind (Rec prs) = mapM_ (lintSingleBinding TopLevel Recursive) prs
lint_bind (NonRec bndr rhs) = lintSingleBinding TopLevel NonRecursive (bndr,rhs)
-
- display bad_news
- = vcat [ text ("*** Core Lint Errors: in result of " ++ whoDunnit ++ " ***"),
- bad_news,
- ptext SLIT("*** Offending Program ***"),
- pprCoreBindings binds,
- ptext SLIT("*** End of Offense ***")
- ]
\end{code}
%************************************************************************
-> Maybe Message -- Nothing => OK
lintUnfolding locn vars expr
- = initL (addLoc (ImportedUnfolding locn) $
- addInScopeVars vars $
- lintCoreExpr expr)
+ | isEmptyBag errs = Nothing
+ | otherwise = Just (pprMessageBag errs)
+ where
+ (_warns, errs) = initL (addLoc (ImportedUnfolding locn) $
+ addInScopeVars vars $
+ lintCoreExpr expr)
\end{code}
%************************************************************************
-- Check whether binder's specialisations contain any out-of-scope variables
; mapM_ (checkBndrIdInScope binder) bndr_vars
+ ; when (isNonRuleLoopBreaker (idOccInfo binder) && isInlinePragma (idInlinePragma binder))
+ (addWarnL (ptext (sLit "INLINE binder is (non-rule) loop breaker:") <+> ppr binder))
+ -- Only non-rule loop breakers inhibit inlining
+
-- Check whether arity and demand type are consistent (only if demand analysis
-- already happened)
; checkL (case maybeDmdTy of
-- the unfolding is a SimplifiableCoreExpr. Give up for now.
where
binder_ty = idType binder
- maybeDmdTy = idNewStrictness_maybe binder
+ maybeDmdTy = idStrictness_maybe binder
bndr_vars = varSetElems (idFreeVars binder)
lintBinder var | isId var = lintIdBndr var $ \_ -> (return ())
| otherwise = return ()
\begin{code}
type InType = Type -- Substitution not yet applied
-type OutType = Type -- Substitution has been applied to this
+type InVar = Var
+type InTyVar = TyVar
+
+type OutType = Type -- Substitution has been applied to this
+type OutVar = Var
+type OutTyVar = TyVar
+type OutCoVar = CoVar
lintCoreExpr :: CoreExpr -> LintM OutType
-- The returned type has the substitution from the monad
-- already applied to it:
-- lintCoreExpr e subst = exprType (subst e)
+--
+-- The returned "type" can be a kind, if the expression is (Type ty)
lintCoreExpr (Var var)
= do { checkL (not (var == oneTupleDataConId))
- (ptext SLIT("Illegal one-tuple"))
+ (ptext (sLit "Illegal one-tuple"))
+
+ ; checkDeadIdOcc var
; var' <- lookupIdInScope var
- ; return (idType var')
- }
+ ; return (idType var') }
lintCoreExpr (Lit lit)
= return (literalType lit)
---lintCoreExpr (Note (Coerce to_ty from_ty) expr)
--- = do { expr_ty <- lintCoreExpr expr
--- ; to_ty <- lintTy to_ty
--- ; from_ty <- lintTy from_ty
--- ; checkTys from_ty expr_ty (mkCoerceErr from_ty expr_ty)
--- ; return to_ty }
-
lintCoreExpr (Cast expr co)
= do { expr_ty <- lintCoreExpr expr
- ; co' <- lintTy co
- ; let (from_ty, to_ty) = coercionKind co'
+ ; co' <- applySubst co
+ ; (from_ty, to_ty) <- lintCoercion co'
; checkTys from_ty expr_ty (mkCastErr from_ty expr_ty)
; return to_ty }
lintCoreExpr (Note _ expr)
= lintCoreExpr expr
+lintCoreExpr (Let (NonRec tv (Type ty)) body)
+ | isTyVar tv
+ = -- See Note [Linting type lets]
+ do { ty' <- addLoc (RhsOf tv) $ lintInTy ty
+ ; lintTyBndr tv $ \ tv' ->
+ addLoc (BodyOfLetRec [tv]) $
+ extendSubstL tv' ty' $ do
+ { checkKinds tv' ty'
+ -- Now extend the substitution so we
+ -- take advantage of it in the body
+ ; lintCoreExpr body } }
+
+ | isCoVar tv
+ = do { co <- applySubst ty
+ ; (s1,s2) <- addLoc (RhsOf tv) $ lintCoercion co
+ ; lintTyBndr tv $ \ tv' ->
+ addLoc (BodyOfLetRec [tv]) $ do
+ { let (t1,t2) = coVarKind tv'
+ ; checkTys s1 t1 (mkTyVarLetErr tv ty)
+ ; checkTys s2 t2 (mkTyVarLetErr tv ty)
+ ; lintCoreExpr body } }
+
+ | otherwise
+ = failWithL (mkTyVarLetErr tv ty) -- Not quite accurate
+
lintCoreExpr (Let (NonRec bndr rhs) body)
= do { lintSingleBinding NotTopLevel NonRecursive (bndr,rhs)
; addLoc (BodyOfLetRec [bndr])
lintCoreExpr (Let (Rec pairs) body)
= lintAndScopeIds bndrs $ \_ ->
- do { mapM (lintSingleBinding NotTopLevel Recursive) pairs
+ do { mapM_ (lintSingleBinding NotTopLevel Recursive) pairs
; addLoc (BodyOfLetRec bndrs) (lintCoreExpr body) }
where
bndrs = map fst pairs
-lintCoreExpr e@(App fun (Type ty))
--- See Note [Type let] above
- = addLoc (AnExpr e) $
- go fun [ty]
- where
- go (App fun (Type ty)) tys
- = do { go fun (ty:tys) }
- go (Lam tv body) (ty:tys)
- = do { checkL (isTyVar tv) (mkKindErrMsg tv ty) -- Not quite accurate
- ; ty' <- lintTy ty
- ; let kind = tyVarKind tv
- ; kind' <- lintTy kind
- ; let tv' = setTyVarKind tv kind'
- ; checkKinds tv' ty'
- -- Now extend the substitution so we
- -- take advantage of it in the body
- ; addInScopeVars [tv'] $
- extendSubstL tv' ty' $
- go body tys }
- go fun tys
- = do { fun_ty <- lintCoreExpr fun
- ; lintCoreArgs fun_ty (map Type tys) }
-
lintCoreExpr e@(App fun arg)
= do { fun_ty <- lintCoreExpr fun
; addLoc (AnExpr e) $
lintCoreExpr e@(Case scrut var alt_ty alts) =
-- Check the scrutinee
do { scrut_ty <- lintCoreExpr scrut
- ; alt_ty <- lintTy alt_ty
- ; var_ty <- lintTy (idType var)
+ ; alt_ty <- lintInTy alt_ty
+ ; var_ty <- lintInTy (idType var)
+
+ ; let mb_tc_app = splitTyConApp_maybe (idType var)
+ ; case mb_tc_app of
+ Just (tycon, _)
+ | debugIsOn &&
+ isAlgTyCon tycon &&
+ not (isFamilyTyCon tycon || isAbstractTyCon tycon) &&
+ null (tyConDataCons tycon) ->
+ pprTrace "Lint warning: case binder's type has no constructors" (ppr var <+> ppr (idType var))
+ -- This can legitimately happen for type families
+ $ return ()
+ _otherwise -> return ()
+
-- Don't use lintIdBndr on var, because unboxed tuple is legitimate
; subst <- getTvSubst
else lintAndScopeId var
; scope $ \_ ->
do { -- Check the alternatives
- mapM (lintCoreAlt scrut_ty alt_ty) alts
+ mapM_ (lintCoreAlt scrut_ty alt_ty) alts
; checkCaseAlts e scrut_ty alts
; return alt_ty } }
where
pass_var f = f var
-lintCoreExpr e@(Type _)
- = addErrL (mkStrangeTyMsg e)
+lintCoreExpr (Type ty)
+ = do { ty' <- lintInTy ty
+ ; return (typeKind ty') }
\end{code}
%************************************************************************
subtype of the required type, as one would expect.
\begin{code}
-lintCoreArgs :: OutType -> [CoreArg] -> LintM OutType
-lintCoreArg :: OutType -> CoreArg -> LintM OutType
--- First argument has already had substitution applied to it
-\end{code}
+lintCoreArg :: OutType -> CoreArg -> LintM OutType
+lintCoreArg fun_ty (Type arg_ty)
+ = do { arg_ty' <- applySubst arg_ty
+ ; lintTyApp fun_ty arg_ty' }
+
+lintCoreArg fun_ty arg
+ = do { arg_ty <- lintCoreExpr arg
+ ; lintValApp arg fun_ty arg_ty }
+
+-----------------
+lintAltBinders :: OutType -- Scrutinee type
+ -> OutType -- Constructor type
+ -> [OutVar] -- Binders
+ -> LintM ()
+lintAltBinders scrut_ty con_ty []
+ = checkTys con_ty scrut_ty (mkBadPatMsg con_ty scrut_ty)
+lintAltBinders scrut_ty con_ty (bndr:bndrs)
+ | isTyCoVar bndr
+ = do { con_ty' <- lintTyApp con_ty (mkTyVarTy bndr)
+ ; lintAltBinders scrut_ty con_ty' bndrs }
+ | otherwise
+ = do { con_ty' <- lintValApp (Var bndr) con_ty (idType bndr)
+ ; lintAltBinders scrut_ty con_ty' bndrs }
-\begin{code}
-lintCoreArgs ty [] = return ty
-lintCoreArgs ty (a : args) =
- do { res <- lintCoreArg ty a
- ; lintCoreArgs res args }
-
-lintCoreArg fun_ty (Type arg_ty) =
- do { arg_ty <- lintTy arg_ty
- ; lintTyApp fun_ty arg_ty }
-
-lintCoreArg fun_ty arg =
- -- Make sure function type matches argument
- do { arg_ty <- lintCoreExpr arg
- ; let err1 = mkAppMsg fun_ty arg_ty arg
- err2 = mkNonFunAppMsg fun_ty arg_ty arg
- ; case splitFunTy_maybe fun_ty of
- Just (arg,res) ->
- do { checkTys arg arg_ty err1
- ; return res }
- _ -> addErrL err2 }
+-----------------
+lintTyApp :: OutType -> OutType -> LintM OutType
+lintTyApp fun_ty arg_ty
+ | Just (tyvar,body_ty) <- splitForAllTy_maybe fun_ty
+ = do { checkKinds tyvar arg_ty
+ ; if isCoVar tyvar then
+ return body_ty -- Co-vars don't appear in body_ty!
+ else
+ return (substTyWith [tyvar] [arg_ty] body_ty) }
+ | otherwise
+ = failWithL (mkTyAppMsg fun_ty arg_ty)
+
+-----------------
+lintValApp :: CoreExpr -> OutType -> OutType -> LintM OutType
+lintValApp arg fun_ty arg_ty
+ | Just (arg,res) <- splitFunTy_maybe fun_ty
+ = do { checkTys arg arg_ty err1
+ ; return res }
+ | otherwise
+ = failWithL err2
+ where
+ err1 = mkAppMsg fun_ty arg_ty arg
+ err2 = mkNonFunAppMsg fun_ty arg_ty arg
\end{code}
\begin{code}
+checkKinds :: Var -> OutType -> LintM ()
-- Both args have had substitution applied
-lintTyApp :: OutType -> OutType -> LintM OutType
-lintTyApp ty arg_ty
- = case splitForAllTy_maybe ty of
- Nothing -> addErrL (mkTyAppMsg ty arg_ty)
-
- Just (tyvar,body)
- -> do { checkL (isTyVar tyvar) (mkTyAppMsg ty arg_ty)
- ; checkKinds tyvar arg_ty
- ; return (substTyWith [tyvar] [arg_ty] body) }
-
-checkKinds :: Var -> Type -> LintM ()
checkKinds tyvar arg_ty
-- Arg type might be boxed for a function with an uncommitted
-- tyvar; notably this is used so that we can give
-- error :: forall a:*. String -> a
-- and then apply it to both boxed and unboxed types.
- = checkL (arg_kind `isSubKind` tyvar_kind)
- (mkKindErrMsg tyvar arg_ty)
+ | isCoVar tyvar = do { (s2,t2) <- lintCoercion arg_ty
+ ; unless (s1 `coreEqType` s2 && t1 `coreEqType` t2)
+ (addErrL (mkCoAppErrMsg tyvar arg_ty)) }
+ | otherwise = do { arg_kind <- lintType arg_ty
+ ; unless (arg_kind `isSubKind` tyvar_kind)
+ (addErrL (mkKindErrMsg tyvar arg_ty)) }
where
tyvar_kind = tyVarKind tyvar
- arg_kind | isCoVar tyvar = coercionKindPredTy arg_ty
- | otherwise = typeKind arg_ty
+ (s1,t1) = coVarKind tyvar
+
+checkDeadIdOcc :: Id -> LintM ()
+-- Occurrences of an Id should never be dead....
+-- except when we are checking a case pattern
+checkDeadIdOcc id
+ | isDeadOcc (idOccInfo id)
+ = do { in_case <- inCasePat
+ ; checkL in_case
+ (ptext (sLit "Occurrence of a dead Id") <+> ppr id) }
+ | otherwise
+ = return ()
\end{code}
lit_ty = literalType lit
lintCoreAlt scrut_ty alt_ty alt@(DataAlt con, args, rhs)
- | isNewTyCon (dataConTyCon con) = addErrL (mkNewTyDataConAltMsg scrut_ty alt)
+ | isNewTyCon (dataConTyCon con)
+ = addErrL (mkNewTyDataConAltMsg scrut_ty alt)
| Just (tycon, tycon_arg_tys) <- splitTyConApp_maybe scrut_ty
= addLoc (CaseAlt alt) $ do
{ -- First instantiate the universally quantified
; let con_payload_ty = applyTys (dataConRepType con) tycon_arg_tys
-- And now bring the new binders into scope
- ; lintBinders args $ \ args -> do
- { addLoc (CasePat alt) $ do
- { -- Check the pattern
- -- Scrutinee type must be a tycon applicn; checked by caller
- -- This code is remarkably compact considering what it does!
- -- NB: args must be in scope here so that the lintCoreArgs
- -- line works.
- -- NB: relies on existential type args coming *after*
- -- ordinary type args
- ; con_result_ty <- lintCoreArgs con_payload_ty (varsToCoreExprs args)
- ; checkTys con_result_ty scrut_ty (mkBadPatMsg con_result_ty scrut_ty)
- }
- -- Check the RHS
+ ; lintBinders args $ \ args' -> do
+ { addLoc (CasePat alt) (lintAltBinders scrut_ty con_payload_ty args')
; checkAltExpr rhs alt_ty } }
| otherwise -- Scrut-ty is wrong shape
lintBinder :: Var -> (Var -> LintM a) -> LintM a
lintBinder var linterF
- | isTyVar var = lint_ty_bndr
- | otherwise = lintIdBndr var linterF
- where
- lint_ty_bndr = do { lintTy (tyVarKind var)
- ; subst <- getTvSubst
- ; let (subst', tv') = substTyVarBndr subst var
- ; updateTvSubst subst' (linterF tv') }
+ | isId var = lintIdBndr var linterF
+ | otherwise = lintTyBndr var linterF
+
+lintTyBndr :: InTyVar -> (OutTyVar -> LintM a) -> LintM a
+lintTyBndr tv thing_inside
+ = do { subst <- getTvSubst
+ ; let (subst', tv') = substTyVarBndr subst tv
+ ; lintTyBndrKind tv'
+ ; updateTvSubst subst' (thing_inside tv') }
-lintIdBndr :: Var -> (Var -> LintM a) -> LintM a
+lintIdBndr :: Id -> (Id -> LintM a) -> LintM a
-- Do substitution on the type of a binder and add the var with this
-- new type to the in-scope set of the second argument
-- ToDo: lint its rules
+
lintIdBndr id linterF
= do { checkL (not (isUnboxedTupleType (idType id)))
(mkUnboxedTupleMsg id)
-- No variable can be bound to an unboxed tuple.
- ; lintAndScopeId id $ \id' -> linterF id'
- }
+ ; lintAndScopeId id $ \id' -> linterF id' }
lintAndScopeIds :: [Var] -> ([Var] -> LintM a) -> LintM a
lintAndScopeIds ids linterF
= go ids
where
go [] = linterF []
- go (id:ids) = do { lintAndScopeId id $ \id ->
- lintAndScopeIds ids $ \ids ->
- linterF (id:ids) }
+ go (id:ids) = lintAndScopeId id $ \id ->
+ lintAndScopeIds ids $ \ids ->
+ linterF (id:ids)
-lintAndScopeId :: Var -> (Var -> LintM a) -> LintM a
+lintAndScopeId :: InVar -> (OutVar -> LintM a) -> LintM a
lintAndScopeId id linterF
- = do { ty <- lintTy (idType id)
- ; let id' = Var.setIdType id ty
- ; addInScopeVars [id'] $ (linterF id')
- }
+ = do { ty <- lintInTy (idType id)
+ ; let id' = setIdType id ty
+ ; addInScopeVar id' $ (linterF id') }
+\end{code}
+
+
+%************************************************************************
+%* *
+\subsection[lint-monad]{The Lint monad}
+%* *
+%************************************************************************
-lintTy :: InType -> LintM OutType
+\begin{code}
+lintInTy :: InType -> LintM OutType
-- Check the type, and apply the substitution to it
+-- See Note [Linting type lets]
-- ToDo: check the kind structure of the type
-lintTy ty
- = do { ty' <- applySubst ty
- ; mapM_ checkTyVarInScope (varSetElems (tyVarsOfType ty'))
+lintInTy ty
+ = addLoc (InType ty) $
+ do { ty' <- applySubst ty
+ ; _ <- lintType ty'
; return ty' }
-\end{code}
+-------------------
+lintKind :: Kind -> LintM ()
+-- Check well-formedness of kinds: *, *->*, etc
+lintKind (TyConApp tc [])
+ | getUnique tc `elem` kindKeys
+ = return ()
+lintKind (FunTy k1 k2)
+ = lintKind k1 >> lintKind k2
+lintKind kind
+ = addErrL (hang (ptext (sLit "Malformed kind:")) 2 (quotes (ppr kind)))
+
+-------------------
+lintTyBndrKind :: OutTyVar -> LintM ()
+lintTyBndrKind tv
+ | isCoVar tv = lintCoVarKind tv
+ | otherwise = lintKind (tyVarKind tv)
+
+-------------------
+lintCoVarKind :: OutCoVar -> LintM ()
+-- Check the kind of a coercion binder
+lintCoVarKind tv
+ = do { (ty1,ty2) <- lintSplitCoVar tv
+ ; k1 <- lintType ty1
+ ; k2 <- lintType ty2
+ ; unless (k1 `eqKind` k2)
+ (addErrL (sep [ ptext (sLit "Kind mis-match in coercion kind of:")
+ , nest 2 (quotes (ppr tv))
+ , ppr [k1,k2] ])) }
+
+-------------------
+lintSplitCoVar :: CoVar -> LintM (Type,Type)
+lintSplitCoVar cv
+ = case coVarKind_maybe cv of
+ Just ts -> return ts
+ Nothing -> failWithL (sep [ ptext (sLit "Coercion variable with non-equality kind:")
+ , nest 2 (ppr cv <+> dcolon <+> ppr (tyVarKind cv))])
+
+-------------------
+lintCoercion :: OutType -> LintM (OutType, OutType)
+-- Check the kind of a coercion term, returning the kind
+lintCoercion ty@(TyVarTy tv)
+ = do { checkTyVarInScope tv
+ ; if isCoVar tv then return (coVarKind tv)
+ else return (ty, ty) }
+
+lintCoercion ty@(AppTy ty1 ty2)
+ = do { (s1,t1) <- lintCoercion ty1
+ ; (s2,t2) <- lintCoercion ty2
+ ; check_co_app ty (typeKind s1) [s2]
+ ; return (AppTy s1 s2, AppTy t1 t2) }
+
+lintCoercion ty@(FunTy ty1 ty2)
+ = do { (s1,t1) <- lintCoercion ty1
+ ; (s2,t2) <- lintCoercion ty2
+ ; check_co_app ty (tyConKind funTyCon) [s1, s2]
+ ; return (FunTy s1 s2, FunTy t1 t2) }
+
+lintCoercion ty@(TyConApp tc tys)
+ | Just (ar, desc) <- isCoercionTyCon_maybe tc
+ = do { unless (tys `lengthAtLeast` ar) (badCo ty)
+ ; (s,t) <- lintCoTyConApp ty desc (take ar tys)
+ ; (ss,ts) <- mapAndUnzipM lintCoercion (drop ar tys)
+ ; check_co_app ty (typeKind s) ss
+ ; return (mkAppTys s ss, mkAppTys t ts) }
+
+ | not (tyConHasKind tc) -- Just something bizarre like SuperKindTyCon
+ = badCo ty
+
+ | otherwise
+ = do { (ss,ts) <- mapAndUnzipM lintCoercion tys
+ ; check_co_app ty (tyConKind tc) ss
+ ; return (TyConApp tc ss, TyConApp tc ts) }
+
+lintCoercion ty@(PredTy (ClassP cls tys))
+ = do { (ss,ts) <- mapAndUnzipM lintCoercion tys
+ ; check_co_app ty (tyConKind (classTyCon cls)) ss
+ ; return (PredTy (ClassP cls ss), PredTy (ClassP cls ts)) }
+
+lintCoercion (PredTy (IParam n p_ty))
+ = do { (s,t) <- lintCoercion p_ty
+ ; return (PredTy (IParam n s), PredTy (IParam n t)) }
+
+lintCoercion ty@(PredTy (EqPred {}))
+ = failWithL (badEq ty)
+
+lintCoercion (ForAllTy tv ty)
+ | isCoVar tv
+ = do { (co1, co2) <- lintSplitCoVar tv
+ ; (s1,t1) <- lintCoercion co1
+ ; (s2,t2) <- lintCoercion co2
+ ; (sr,tr) <- lintCoercion ty
+ ; return (mkCoPredTy s1 s2 sr, mkCoPredTy t1 t2 tr) }
+
+ | otherwise
+ = do { lintKind (tyVarKind tv)
+ ; (s,t) <- addInScopeVar tv (lintCoercion ty)
+ ; return (ForAllTy tv s, ForAllTy tv t) }
+
+badCo :: Coercion -> LintM a
+badCo co = failWithL (hang (ptext (sLit "Ill-kinded coercion term:")) 2 (ppr co))
+
+---------------
+lintCoTyConApp :: Coercion -> CoTyConDesc -> [Coercion] -> LintM (Type,Type)
+-- Always called with correct number of coercion arguments
+-- First arg is just for error message
+lintCoTyConApp _ CoLeft (co:_) = lintLR fst co
+lintCoTyConApp _ CoRight (co:_) = lintLR snd co
+lintCoTyConApp _ CoCsel1 (co:_) = lintCsel fstOf3 co
+lintCoTyConApp _ CoCsel2 (co:_) = lintCsel sndOf3 co
+lintCoTyConApp _ CoCselR (co:_) = lintCsel thirdOf3 co
+
+lintCoTyConApp _ CoSym (co:_)
+ = do { (ty1,ty2) <- lintCoercion co
+ ; return (ty2,ty1) }
+
+lintCoTyConApp co CoTrans (co1:co2:_)
+ = do { (ty1a, ty1b) <- lintCoercion co1
+ ; (ty2a, ty2b) <- lintCoercion co2
+ ; checkL (ty1b `coreEqType` ty2a)
+ (hang (ptext (sLit "Trans coercion mis-match:") <+> ppr co)
+ 2 (vcat [ppr ty1a, ppr ty1b, ppr ty2a, ppr ty2b]))
+ ; return (ty1a, ty2b) }
+
+lintCoTyConApp _ CoInst (co:arg_ty:_)
+ = do { co_tys <- lintCoercion co
+ ; arg_kind <- lintType arg_ty
+ ; case decompInst_maybe co_tys of
+ Just ((tv1,tv2), (ty1,ty2))
+ | arg_kind `isSubKind` tyVarKind tv1
+ -> return (substTyWith [tv1] [arg_ty] ty1,
+ substTyWith [tv2] [arg_ty] ty2)
+ | otherwise
+ -> failWithL (ptext (sLit "Kind mis-match in inst coercion"))
+ Nothing -> failWithL (ptext (sLit "Bad argument of inst")) }
+
+lintCoTyConApp _ (CoAxiom { co_ax_tvs = tvs
+ , co_ax_lhs = lhs_ty, co_ax_rhs = rhs_ty }) cos
+ = do { (tys1, tys2) <- mapAndUnzipM lintCoercion cos
+ ; sequence_ (zipWith checkKinds tvs tys1)
+ ; return (substTyWith tvs tys1 lhs_ty,
+ substTyWith tvs tys2 rhs_ty) }
+
+lintCoTyConApp _ CoUnsafe (ty1:ty2:_)
+ = do { _ <- lintType ty1
+ ; _ <- lintType ty2 -- Ignore kinds; it's unsafe!
+ ; return (ty1,ty2) }
+
+lintCoTyConApp _ _ _ = panic "lintCoTyConApp" -- Called with wrong number of coercion args
+
+----------
+lintLR :: (forall a. (a,a)->a) -> Coercion -> LintM (Type,Type)
+lintLR sel co
+ = do { (ty1,ty2) <- lintCoercion co
+ ; case decompLR_maybe (ty1,ty2) of
+ Just res -> return (sel res)
+ Nothing -> failWithL (ptext (sLit "Bad argument of left/right")) }
+
+----------
+lintCsel :: (forall a. (a,a,a)->a) -> Coercion -> LintM (Type,Type)
+lintCsel sel co
+ = do { (ty1,ty2) <- lintCoercion co
+ ; case decompCsel_maybe (ty1,ty2) of
+ Just res -> return (sel res)
+ Nothing -> failWithL (ptext (sLit "Bad argument of csel")) }
+
+-------------------
+lintType :: OutType -> LintM Kind
+lintType (TyVarTy tv)
+ = do { checkTyVarInScope tv
+ ; return (tyVarKind tv) }
+
+lintType ty@(AppTy t1 t2)
+ = do { k1 <- lintType t1
+ ; lint_ty_app ty k1 [t2] }
+
+lintType ty@(FunTy t1 t2)
+ = lint_ty_app ty (tyConKind funTyCon) [t1,t2]
+
+lintType ty@(TyConApp tc tys)
+ | tyConHasKind tc
+ = lint_ty_app ty (tyConKind tc) tys
+ | otherwise
+ = failWithL (hang (ptext (sLit "Malformed type:")) 2 (ppr ty))
+
+lintType (ForAllTy tv ty)
+ = do { lintTyBndrKind tv
+ ; addInScopeVar tv (lintType ty) }
+
+lintType ty@(PredTy (ClassP cls tys))
+ = lint_ty_app ty (tyConKind (classTyCon cls)) tys
+
+lintType (PredTy (IParam _ p_ty))
+ = lintType p_ty
+
+lintType ty@(PredTy (EqPred {}))
+ = failWithL (badEq ty)
+
+----------------
+lint_ty_app :: Type -> Kind -> [OutType] -> LintM Kind
+lint_ty_app ty k tys
+ = do { ks <- mapM lintType tys
+ ; lint_kind_app (ptext (sLit "type") <+> quotes (ppr ty)) k ks }
+
+----------------
+check_co_app :: Coercion -> Kind -> [OutType] -> LintM ()
+check_co_app ty k tys
+ = do { _ <- lint_kind_app (ptext (sLit "coercion") <+> quotes (ppr ty))
+ k (map typeKind tys)
+ ; return () }
+
+----------------
+lint_kind_app :: SDoc -> Kind -> [Kind] -> LintM Kind
+lint_kind_app doc kfn ks = go kfn ks
+ where
+ fail_msg = vcat [hang (ptext (sLit "Kind application error in")) 2 doc,
+ nest 2 (ptext (sLit "Function kind =") <+> ppr kfn),
+ nest 2 (ptext (sLit "Arg kinds =") <+> ppr ks)]
+
+ go kfn [] = return kfn
+ go kfn (k:ks) = case splitKindFunTy_maybe kfn of
+ Nothing -> failWithL fail_msg
+ Just (kfa, kfb) -> do { unless (k `isSubKind` kfa)
+ (addErrL fail_msg)
+ ; go kfb ks }
+--------------
+badEq :: Type -> SDoc
+badEq ty = hang (ptext (sLit "Unexpected equality predicate:"))
+ 1 (quotes (ppr ty))
+\end{code}
%************************************************************************
%* *
TvSubst -> -- Current type substitution; we also use this
-- to keep track of all the variables in scope,
-- both Ids and TyVars
- Bag Message -> -- Error messages so far
- (Maybe a, Bag Message) } -- Result and error messages (if any)
+ WarnsAndErrs -> -- Error and warning messages so far
+ (Maybe a, WarnsAndErrs) } -- Result and messages (if any)
+
+type WarnsAndErrs = (Bag Message, Bag Message)
{- Note [Type substitution]
~~~~~~~~~~~~~~~~~~~~~~~~
instance Monad LintM where
return x = LintM (\ _ _ errs -> (Just x, errs))
- fail err = LintM (\ loc subst errs -> (Nothing, addErr subst errs (text err) loc))
+ fail err = failWithL (text err)
m >>= k = LintM (\ loc subst errs ->
let (res, errs') = unLintM m loc subst errs in
case res of
| LambdaBodyOf Id -- The lambda-binder
| BodyOfLetRec [Id] -- One of the binders
| CaseAlt CoreAlt -- Case alternative
- | CasePat CoreAlt -- *Pattern* of the case alternative
+ | CasePat CoreAlt -- The *pattern* of the case alternative
| AnExpr CoreExpr -- Some expression
| ImportedUnfolding SrcLoc -- Some imported unfolding (ToDo: say which)
| TopLevelBindings
+ | InType Type -- Inside a type
\end{code}
\begin{code}
-initL :: LintM a -> Maybe Message {- errors -}
+initL :: LintM a -> WarnsAndErrs -- Errors and warnings
initL m
- = case unLintM m [] emptyTvSubst emptyBag of
- (_, errs) | isEmptyBag errs -> Nothing
- | otherwise -> Just (vcat (punctuate (text "") (bagToList errs)))
+ = case unLintM m [] emptyTvSubst (emptyBag, emptyBag) of
+ (_, errs) -> errs
\end{code}
\begin{code}
checkL :: Bool -> Message -> LintM ()
checkL True _ = return ()
-checkL False msg = addErrL msg
+checkL False msg = failWithL msg
+
+failWithL :: Message -> LintM a
+failWithL msg = LintM $ \ loc subst (warns,errs) ->
+ (Nothing, (warns, addMsg subst errs msg loc))
+
+addErrL :: Message -> LintM ()
+addErrL msg = LintM $ \ loc subst (warns,errs) ->
+ (Just (), (warns, addMsg subst errs msg loc))
-addErrL :: Message -> LintM a
-addErrL msg = LintM (\ loc subst errs -> (Nothing, addErr subst errs msg loc))
+addWarnL :: Message -> LintM ()
+addWarnL msg = LintM $ \ loc subst (warns,errs) ->
+ (Just (), (addMsg subst warns msg loc, errs))
-addErr :: TvSubst -> Bag Message -> Message -> [LintLocInfo] -> Bag Message
-addErr subst errs_so_far msg locs
+addMsg :: TvSubst -> Bag Message -> Message -> [LintLocInfo] -> Bag Message
+addMsg subst msgs msg locs
= ASSERT( notNull locs )
- errs_so_far `snocBag` mk_msg msg
+ msgs `snocBag` mk_msg msg
where
(loc, cxt1) = dumpLoc (head locs)
cxts = [snd (dumpLoc loc) | loc <- locs]
context | opt_PprStyle_Debug = vcat (reverse cxts) $$ cxt1 $$
- ptext SLIT("Substitution:") <+> ppr subst
+ ptext (sLit "Substitution:") <+> ppr subst
| otherwise = cxt1
mk_msg msg = mkLocMessage (mkSrcSpan loc loc) (context $$ msg)
addLoc extra_loc m =
LintM (\ loc subst errs -> unLintM m (extra_loc:loc) subst errs)
+inCasePat :: LintM Bool -- A slight hack; see the unique call site
+inCasePat = LintM $ \ loc _ errs -> (Just (is_case_pat loc), errs)
+ where
+ is_case_pat (CasePat {} : _) = True
+ is_case_pat _other = False
+
addInScopeVars :: [Var] -> LintM a -> LintM a
addInScopeVars vars m
| null dups
- = LintM (\ loc subst errs -> unLintM m loc (extendTvInScope subst vars) errs)
+ = LintM (\ loc subst errs -> unLintM m loc (extendTvInScopeList subst vars) errs)
| otherwise
- = addErrL (dupVars dups)
+ = failWithL (dupVars dups)
where
(_, dups) = removeDups compare vars
+addInScopeVar :: Var -> LintM a -> LintM a
+addInScopeVar var m
+ = LintM (\ loc subst errs -> unLintM m loc (extendTvInScope subst var) errs)
+
updateTvSubst :: TvSubst -> LintM a -> LintM a
updateTvSubst subst' m =
LintM (\ loc _ errs -> unLintM m loc subst' errs)
Nothing -> do { addErrL out_of_scope
; return id } }
where
- out_of_scope = ppr id <+> ptext SLIT("is out of scope")
+ out_of_scope = ppr id <+> ptext (sLit "is out of scope")
oneTupleDataConId :: Id -- Should not happen
checkBndrIdInScope binder id
= checkInScope msg id
where
- msg = ptext SLIT("is out of scope inside info for") <+>
+ msg = ptext (sLit "is out of scope inside info for") <+>
ppr binder
checkTyVarInScope :: TyVar -> LintM ()
-checkTyVarInScope tv = checkInScope (ptext SLIT("is out of scope")) tv
+checkTyVarInScope tv = checkInScope (ptext (sLit "is out of scope")) tv
checkInScope :: SDoc -> Var -> LintM ()
checkInScope loc_msg var =
; checkL (not (mustHaveLocalBinding var) || (var `isInScope` subst))
(hsep [ppr var, loc_msg]) }
-checkTys :: Type -> Type -> Message -> LintM ()
+checkTys :: OutType -> OutType -> Message -> LintM ()
-- check ty2 is subtype of ty1 (ie, has same structure but usage
-- annotations need only be consistent, not equal)
-- Assumes ty1,ty2 are have alrady had the substitution applied
dumpLoc :: LintLocInfo -> (SrcLoc, SDoc)
dumpLoc (RhsOf v)
- = (getSrcLoc v, brackets (ptext SLIT("RHS of") <+> pp_binders [v]))
+ = (getSrcLoc v, brackets (ptext (sLit "RHS of") <+> pp_binders [v]))
dumpLoc (LambdaBodyOf b)
- = (getSrcLoc b, brackets (ptext SLIT("in body of lambda with binder") <+> pp_binder b))
+ = (getSrcLoc b, brackets (ptext (sLit "in body of lambda with binder") <+> pp_binder b))
dumpLoc (BodyOfLetRec [])
- = (noSrcLoc, brackets (ptext SLIT("In body of a letrec with no binders")))
+ = (noSrcLoc, brackets (ptext (sLit "In body of a letrec with no binders")))
dumpLoc (BodyOfLetRec bs@(_:_))
- = ( getSrcLoc (head bs), brackets (ptext SLIT("in body of letrec with binders") <+> pp_binders bs))
+ = ( getSrcLoc (head bs), brackets (ptext (sLit "in body of letrec with binders") <+> pp_binders bs))
dumpLoc (AnExpr e)
= (noSrcLoc, text "In the expression:" <+> ppr e)
= (noSrcLoc, text "In the pattern of a case alternative:" <+> parens (ppr con <+> pp_binders args))
dumpLoc (ImportedUnfolding locn)
- = (locn, brackets (ptext SLIT("in an imported unfolding")))
+ = (locn, brackets (ptext (sLit "in an imported unfolding")))
dumpLoc TopLevelBindings
= (noSrcLoc, empty)
+dumpLoc (InType ty)
+ = (noSrcLoc, text "In the type" <+> quotes (ppr ty))
pp_binders :: [Var] -> SDoc
pp_binders bs = sep (punctuate comma (map pp_binder bs))
= vcat [text "Result binder in case doesn't match scrutinee:" <+> ppr var,
text "Result binder type:" <+> ppr var_ty,--(idType var),
text "Scrutinee type:" <+> ppr scrut_ty,
- hsep [ptext SLIT("Current TV subst"), ppr subst]]
+ hsep [ptext (sLit "Current TV subst"), ppr subst]]
mkNonDefltMsg, mkNonIncreasingAltsMsg :: CoreExpr -> Message
mkNonDefltMsg e
mkAppMsg :: Type -> Type -> CoreExpr -> Message
mkAppMsg fun_ty arg_ty arg
- = vcat [ptext SLIT("Argument value doesn't match argument type:"),
- hang (ptext SLIT("Fun type:")) 4 (ppr fun_ty),
- hang (ptext SLIT("Arg type:")) 4 (ppr arg_ty),
- hang (ptext SLIT("Arg:")) 4 (ppr arg)]
+ = vcat [ptext (sLit "Argument value doesn't match argument type:"),
+ hang (ptext (sLit "Fun type:")) 4 (ppr fun_ty),
+ hang (ptext (sLit "Arg type:")) 4 (ppr arg_ty),
+ hang (ptext (sLit "Arg:")) 4 (ppr arg)]
mkNonFunAppMsg :: Type -> Type -> CoreExpr -> Message
mkNonFunAppMsg fun_ty arg_ty arg
- = vcat [ptext SLIT("Non-function type in function position"),
- hang (ptext SLIT("Fun type:")) 4 (ppr fun_ty),
- hang (ptext SLIT("Arg type:")) 4 (ppr arg_ty),
- hang (ptext SLIT("Arg:")) 4 (ppr arg)]
+ = vcat [ptext (sLit "Non-function type in function position"),
+ hang (ptext (sLit "Fun type:")) 4 (ppr fun_ty),
+ hang (ptext (sLit "Arg type:")) 4 (ppr arg_ty),
+ hang (ptext (sLit "Arg:")) 4 (ppr arg)]
+
+mkTyVarLetErr :: TyVar -> Type -> Message
+mkTyVarLetErr tyvar ty
+ = vcat [ptext (sLit "Bad `let' binding for type or coercion variable:"),
+ hang (ptext (sLit "Type/coercion variable:"))
+ 4 (ppr tyvar <+> dcolon <+> ppr (tyVarKind tyvar)),
+ hang (ptext (sLit "Arg type/coercion:"))
+ 4 (ppr ty)]
mkKindErrMsg :: TyVar -> Type -> Message
mkKindErrMsg tyvar arg_ty
- = vcat [ptext SLIT("Kinds don't match in type application:"),
- hang (ptext SLIT("Type variable:"))
+ = vcat [ptext (sLit "Kinds don't match in type application:"),
+ hang (ptext (sLit "Type variable:"))
4 (ppr tyvar <+> dcolon <+> ppr (tyVarKind tyvar)),
- hang (ptext SLIT("Arg type:"))
+ hang (ptext (sLit "Arg type:"))
4 (ppr arg_ty <+> dcolon <+> ppr (typeKind arg_ty))]
+mkCoAppErrMsg :: TyVar -> Type -> Message
+mkCoAppErrMsg tyvar arg_ty
+ = vcat [ptext (sLit "Kinds don't match in coercion application:"),
+ hang (ptext (sLit "Coercion variable:"))
+ 4 (ppr tyvar <+> dcolon <+> ppr (tyVarKind tyvar)),
+ hang (ptext (sLit "Arg coercion:"))
+ 4 (ppr arg_ty <+> dcolon <+> pprEqPred (coercionKind arg_ty))]
+
mkTyAppMsg :: Type -> Type -> Message
mkTyAppMsg ty arg_ty
= vcat [text "Illegal type application:",
- hang (ptext SLIT("Exp type:"))
+ hang (ptext (sLit "Exp type:"))
4 (ppr ty <+> dcolon <+> ppr (typeKind ty)),
- hang (ptext SLIT("Arg type:"))
+ hang (ptext (sLit "Arg type:"))
4 (ppr arg_ty <+> dcolon <+> ppr (typeKind arg_ty))]
mkRhsMsg :: Id -> Type -> Message
mkRhsMsg binder ty
= vcat
- [hsep [ptext SLIT("The type of this binder doesn't match the type of its RHS:"),
+ [hsep [ptext (sLit "The type of this binder doesn't match the type of its RHS:"),
ppr binder],
- hsep [ptext SLIT("Binder's type:"), ppr (idType binder)],
- hsep [ptext SLIT("Rhs type:"), ppr ty]]
+ hsep [ptext (sLit "Binder's type:"), ppr (idType binder)],
+ hsep [ptext (sLit "Rhs type:"), ppr ty]]
mkRhsPrimMsg :: Id -> CoreExpr -> Message
mkRhsPrimMsg binder _rhs
- = vcat [hsep [ptext SLIT("The type of this binder is primitive:"),
+ = vcat [hsep [ptext (sLit "The type of this binder is primitive:"),
ppr binder],
- hsep [ptext SLIT("Binder's type:"), ppr (idType binder)]
+ hsep [ptext (sLit "Binder's type:"), ppr (idType binder)]
]
mkStrictMsg :: Id -> Message
mkStrictMsg binder
- = vcat [hsep [ptext SLIT("Recursive or top-level binder has strict demand info:"),
+ = vcat [hsep [ptext (sLit "Recursive or top-level binder has strict demand info:"),
ppr binder],
- hsep [ptext SLIT("Binder's demand info:"), ppr (idNewDemandInfo binder)]
+ hsep [ptext (sLit "Binder's demand info:"), ppr (idDemandInfo binder)]
]
mkArityMsg :: Id -> Message
mkArityMsg binder
- = vcat [hsep [ptext SLIT("Demand type has "),
+ = vcat [hsep [ptext (sLit "Demand type has "),
ppr (dmdTypeDepth dmd_ty),
- ptext SLIT(" arguments, rhs has "),
+ ptext (sLit " arguments, rhs has "),
ppr (idArity binder),
- ptext SLIT("arguments, "),
+ ptext (sLit "arguments, "),
ppr binder],
- hsep [ptext SLIT("Binder's strictness signature:"), ppr dmd_ty]
+ hsep [ptext (sLit "Binder's strictness signature:"), ppr dmd_ty]
]
- where (StrictSig dmd_ty) = idNewStrictness binder
+ where (StrictSig dmd_ty) = idStrictness binder
mkUnboxedTupleMsg :: Id -> Message
mkUnboxedTupleMsg binder
- = vcat [hsep [ptext SLIT("A variable has unboxed tuple type:"), ppr binder],
- hsep [ptext SLIT("Binder's type:"), ppr (idType binder)]]
+ = vcat [hsep [ptext (sLit "A variable has unboxed tuple type:"), ppr binder],
+ hsep [ptext (sLit "Binder's type:"), ppr (idType binder)]]
mkCastErr :: Type -> Type -> Message
mkCastErr from_ty expr_ty
- = vcat [ptext SLIT("From-type of Cast differs from type of enclosed expression"),
- ptext SLIT("From-type:") <+> ppr from_ty,
- ptext SLIT("Type of enclosed expr:") <+> ppr expr_ty
+ = vcat [ptext (sLit "From-type of Cast differs from type of enclosed expression"),
+ ptext (sLit "From-type:") <+> ppr from_ty,
+ ptext (sLit "Type of enclosed expr:") <+> ppr expr_ty
]
dupVars :: [[Var]] -> Message
dupVars vars
- = hang (ptext SLIT("Duplicate variables brought into scope"))
+ = hang (ptext (sLit "Duplicate variables brought into scope"))
2 (ppr vars)
-
-mkStrangeTyMsg :: CoreExpr -> Message
-mkStrangeTyMsg e
- = ptext SLIT("Type where expression expected:") <+> ppr e
\end{code}
projects / ghc-hetmet.git / blobdiff