%
-% (c) The GRASP/AQUA Project, Glasgow University, 1993-1995
+% (c) The GRASP/AQUA Project, Glasgow University, 1993-1998
%
\section[CoreLint]{A ``lint'' pass to check for Core correctness}
\begin{code}
-#include "HsVersions.h"
-
module CoreLint (
lintCoreBindings,
- lintUnfolding,
-
- PprStyle, CoreBinding, PlainCoreBinding(..), Id
+ lintUnfolding,
+ showPass, endPass
) where
-IMPORT_Trace
+#include "HsVersions.h"
+
+import CoreSyn
+import CoreFVs ( idFreeVars )
+import CoreUtils ( findDefault, exprOkForSpeculation, coreBindsSize, mkPiType )
-import AbsPrel ( typeOfPrimOp, mkFunTy, PrimOp(..), PrimKind
- IF_ATTACK_PRAGMAS(COMMA tagOf_PrimOp)
- IF_ATTACK_PRAGMAS(COMMA pprPrimOp)
- )
-import AbsUniType
import Bag
-import BasicLit ( typeOfBasicLit, BasicLit )
-import CoreSyn ( pprCoreBinding ) -- ToDo: correctly
-import Id ( getIdUniType, isNullaryDataCon, isBottomingId,
- getInstantiatedDataConSig, Id
- IF_ATTACK_PRAGMAS(COMMA bottomIsGuaranteed)
+import Literal ( literalType )
+import DataCon ( dataConRepType )
+import Var ( Var, Id, TyVar, idType, tyVarKind, isTyVar, isId, mustHaveLocalBinding )
+import VarSet
+import Subst ( substTyWith )
+import Name ( getSrcLoc )
+import PprCore
+import ErrUtils ( dumpIfSet_core, ghcExit, Message, showPass,
+ addErrLocHdrLine )
+import SrcLoc ( SrcLoc, noSrcLoc )
+import Type ( Type, tyVarsOfType, eqType,
+ splitFunTy_maybe, mkTyVarTy,
+ splitForAllTy_maybe, splitTyConApp_maybe, splitTyConApp,
+ isUnLiftedType, typeKind,
+ isUnboxedTupleType,
+ hasMoreBoxityInfo
)
-import Maybes
+import TyCon ( isPrimTyCon )
+import BasicTypes ( RecFlag(..), isNonRec )
+import CmdLineOpts
+import Maybe
import Outputable
-import PlainCore
-import Pretty
-import SrcLoc ( SrcLoc )
-import UniqSet
-import Util
-infixr 9 `thenL`, `thenL_`, `thenMaybeL`, `thenMaybeL_`
+import IO ( hPutStrLn, stderr )
+
+infixr 9 `thenL`, `seqL`
\end{code}
-Checks for
- (a) type errors
- (b) locally-defined variables used but not defined
+%************************************************************************
+%* *
+\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 dflags pass_name dump_flag binds
+ = do
+ -- Report result size if required
+ -- This has the side effect of forcing the intermediate to be evaluated
+ if verbosity dflags >= 2 then
+ hPutStrLn stderr (" Result size = " ++ show (coreBindsSize binds))
+ else
+ return ()
+
+ -- Report verbosely, if required
+ dumpIfSet_core dflags dump_flag pass_name (pprCoreBindings binds)
+
+ -- Type check
+ lintCoreBindings dflags pass_name binds
+
+ return binds
+\end{code}
-Doesn't check for out-of-scope type variables, because they can
-legitimately arise. Eg
-\begin{verbatim}
- k = /\a b -> \x::a y::b -> x
- f = /\c -> \z::c -> k c w z (error w "foo")
-\end{verbatim}
-Here \tr{w} is just a free type variable.
%************************************************************************
%* *
-\subsection{``lint'' for various constructs}
+\subsection[lintCoreBindings]{@lintCoreBindings@: Top-level interface}
%* *
%************************************************************************
-@lintCoreBindings@ is the top-level interface function.
+Checks that a set of core bindings is well-formed. The PprStyle and String
+just control what we print in the event of an error. The Bool value
+indicates whether we have done any specialisation yet (in which case we do
+some extra checks).
+
+We check for
+ (a) type errors
+ (b) Out-of-scope type variables
+ (c) Out-of-scope local variables
+ (d) Ill-kinded types
+
+If we have done specialisation the we check that there are
+ (a) No top-level bindings of primitive (unboxed type)
+
+Outstanding issues:
+
+ --
+ -- Things are *not* OK if:
+ --
+ -- * Unsaturated type app before specialisation has been done;
+ --
+ -- * Oversaturated type app after specialisation (eta reduction
+ -- may well be happening...);
\begin{code}
-lintCoreBindings :: PprStyle -> String -> Bool -> [PlainCoreBinding] -> [PlainCoreBinding]
-
-lintCoreBindings sty whodunnit spec_done binds
- = BSCC("CoreLint")
- case (initL (lint_binds binds) spec_done) of
- Nothing -> binds
- Just msg -> pprPanic "" (ppAboves [
- ppStr ("*** Core Lint Errors: in "++whodunnit++" ***"),
- msg sty,
- ppStr "*** Offending Program ***",
- ppAboves (map (pprCoreBinding sty pprBigCoreBinder pprTypedCoreBinder ppr) binds),
- ppStr "*** End of Offense ***"])
- ESCC
+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 1
where
- lint_binds :: [PlainCoreBinding] -> LintM ()
-
- lint_binds [] = returnL ()
- lint_binds (bind:binds)
- = lintCoreBinds bind `thenL` \ binders ->
- addInScopeVars binders (
- lint_binds binds
- )
+ -- Put all the top-level binders in scope at the start
+ -- This is because transformation rules can bring something
+ -- into use 'unexpectedly'
+ lint_binds binds = addInScopeVars (bindersOfBinds binds) $
+ mapL lint_bind binds
+
+ lint_bind (Rec prs) = mapL (lintSingleBinding Recursive) prs `seqL`
+ returnL ()
+ lint_bind (NonRec bndr rhs) = lintSingleBinding 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}
+%************************************************************************
+%* *
+\subsection[lintUnfolding]{lintUnfolding}
+%* *
+%************************************************************************
+
We use this to check all unfoldings that come in from interfaces
(it is very painful to catch errors otherwise):
+
\begin{code}
-lintUnfolding :: SrcLoc -> PlainCoreExpr -> PlainCoreExpr
-
-lintUnfolding locn expr
- = case (initL (addLoc (ImportedUnfolding locn) (lintCoreExpr expr)) True{-pretend spec done-}) of
- Nothing -> expr
- Just msg -> error ("ERROR: Type-incorrect unfolding from an interface:\n"++
- (ppShow 80 (ppAboves [msg PprForUser,
- ppStr "*** Bad unfolding ***",
- ppr PprDebug expr,
- ppStr "*** End of bad unfolding ***"])))
+lintUnfolding :: SrcLoc
+ -> [Var] -- Treat these as in scope
+ -> CoreExpr
+ -> Maybe Message -- Nothing => OK
+
+lintUnfolding locn vars expr
+ = initL (addLoc (ImportedUnfolding locn) $
+ addInScopeVars vars $
+ lintCoreExpr expr)
\end{code}
-\begin{code}
-lintCoreAtom :: PlainCoreAtom -> LintM (Maybe UniType)
+%************************************************************************
+%* *
+\subsection[lintCoreBinding]{lintCoreBinding}
+%* *
+%************************************************************************
-lintCoreAtom (CoLitAtom lit) = returnL (Just (typeOfBasicLit lit))
-lintCoreAtom a@(CoVarAtom v)
- = checkInScope v `thenL_`
- returnL (Just (getIdUniType v))
-\end{code}
+Check a core binding, returning the list of variables bound.
\begin{code}
-lintCoreBinds :: PlainCoreBinding -> LintM [Id] -- Returns the binders
-lintCoreBinds (CoNonRec binder rhs)
- = lint_binds_help (binder,rhs) `thenL_`
- returnL [binder]
-
-lintCoreBinds (CoRec pairs)
- = addInScopeVars binders (
- mapL lint_binds_help pairs `thenL_`
- returnL binders
- )
- where
- binders = [b | (b,_) <- pairs]
+lintSingleBinding rec_flag (binder,rhs)
+ = addLoc (RhsOf binder) $
-lint_binds_help (binder,rhs)
- = addLoc (RhsOf binder) (
-- Check the rhs
- lintCoreExpr rhs `thenL` \ maybe_rhs_ty ->
+ lintCoreExpr rhs `thenL` \ ty ->
-- Check match to RHS type
- (case maybe_rhs_ty of
- Nothing -> returnL ()
- Just rhs_ty -> checkTys (getIdUniType binder)
- rhs_ty
- (mkRhsMsg binder rhs_ty)
- ) `thenL_`
-
- -- Check not isPrimType
- checkL (not (isPrimType (getIdUniType binder)))
- (mkRhsPrimMsg binder rhs)
- `thenL_`
-
- -- Check unfolding, if any
- -- Blegh. This is tricky, because the unfolding is a SimplifiableCoreExpr
- -- Give up for now
-
- returnL ()
- )
+ lintBinder binder `seqL`
+ checkTys binder_ty ty (mkRhsMsg binder ty) `seqL`
+
+ -- Check (not isUnLiftedType) (also checks for bogus unboxed tuples)
+ checkL (not (isUnLiftedType binder_ty)
+ || (isNonRec rec_flag && exprOkForSpeculation rhs))
+ (mkRhsPrimMsg binder rhs) `seqL`
+
+ -- Check whether binder's specialisations contain any out-of-scope variables
+ mapL (checkBndrIdInScope binder) bndr_vars `seqL`
+ returnL ()
+
+ -- We should check the unfolding, if any, but this is tricky because
+ -- the unfolding is a SimplifiableCoreExpr. Give up for now.
+ where
+ binder_ty = idType binder
+ bndr_vars = varSetElems (idFreeVars binder)
\end{code}
+%************************************************************************
+%* *
+\subsection[lintCoreExpr]{lintCoreExpr}
+%* *
+%************************************************************************
+
\begin{code}
-lintCoreExpr :: PlainCoreExpr -> LintM (Maybe UniType) -- Nothing if error found
-
-lintCoreExpr (CoVar var)
- = checkInScope var `thenL_`
- returnL (Just ty)
-{-
- case (splitForalls ty) of { (tyvars, _) ->
- if null tyvars then
- returnL (Just ty)
- else
- addErrL (mkUnappTyMsg var ty) `thenL_`
- returnL Nothing
- }
--}
+lintCoreExpr :: CoreExpr -> LintM Type
+
+lintCoreExpr (Var var) = checkIdInScope var `seqL` returnL (idType var)
+lintCoreExpr (Lit lit) = returnL (literalType lit)
+
+lintCoreExpr (Note (Coerce to_ty from_ty) expr)
+ = lintCoreExpr expr `thenL` \ expr_ty ->
+ lintTy to_ty `seqL`
+ lintTy from_ty `seqL`
+ checkTys from_ty expr_ty (mkCoerceErr from_ty expr_ty) `seqL`
+ returnL to_ty
+
+lintCoreExpr (Note other_note expr)
+ = lintCoreExpr expr
+
+lintCoreExpr (Let (NonRec bndr rhs) body)
+ = lintSingleBinding NonRecursive (bndr,rhs) `seqL`
+ addLoc (BodyOfLetRec [bndr])
+ (addInScopeVars [bndr] (lintCoreExpr body))
+
+lintCoreExpr (Let (Rec pairs) body)
+ = addInScopeVars bndrs $
+ mapL (lintSingleBinding Recursive) pairs `seqL`
+ addLoc (BodyOfLetRec bndrs) (lintCoreExpr body)
where
- ty = getIdUniType var
+ bndrs = map fst pairs
+
+lintCoreExpr e@(App fun arg)
+ = lintCoreExpr fun `thenL` \ ty ->
+ addLoc (AnExpr e) $
+ lintCoreArg ty arg
+
+lintCoreExpr (Lam var expr)
+ = addLoc (LambdaBodyOf var) $
+ (if isId var then
+ checkL (not (isUnboxedTupleType (idType var))) (mkUnboxedTupleMsg var)
+ else
+ returnL ())
+ `seqL`
+ (addInScopeVars [var] $
+ lintCoreExpr expr `thenL` \ ty ->
+
+ returnL (mkPiType var ty))
+
+lintCoreExpr e@(Case scrut var alts)
+ = -- Check the scrutinee
+ lintCoreExpr scrut `thenL` \ scrut_ty ->
+
+ -- Check the binder
+ lintBinder var `seqL`
+
+ -- If this is an unboxed tuple case, then the binder must be dead
+ {-
+ checkL (if isUnboxedTupleType (idType var)
+ then isDeadBinder var
+ else True) (mkUnboxedTupleMsg var) `seqL`
+ -}
+
+ checkTys (idType var) scrut_ty (mkScrutMsg var scrut_ty) `seqL`
+
+ addInScopeVars [var] (
+
+ -- Check the alternatives
+ checkCaseAlts e scrut_ty alts `seqL`
+
+ mapL (lintCoreAlt scrut_ty) alts `thenL` \ (alt_ty : alt_tys) ->
+ mapL (check alt_ty) alt_tys `seqL`
+ returnL alt_ty)
+ where
+ check alt_ty1 alt_ty2 = checkTys alt_ty1 alt_ty2 (mkCaseAltMsg e)
+
+lintCoreExpr e@(Type ty)
+ = addErrL (mkStrangeTyMsg e)
+\end{code}
-lintCoreExpr (CoLit lit) = returnL (Just (typeOfBasicLit lit))
-lintCoreExpr (CoSCC label expr) = lintCoreExpr expr
+%************************************************************************
+%* *
+\subsection[lintCoreArgs]{lintCoreArgs}
+%* *
+%************************************************************************
-lintCoreExpr (CoLet binds body)
- = lintCoreBinds binds `thenL` \ binders ->
- ASSERT(not (null binders))
- addLoc (BodyOfLetRec binders) (
- addInScopeVars binders (
- lintCoreExpr body
- ))
+The basic version of these functions checks that the argument is a
+subtype of the required type, as one would expect.
-lintCoreExpr e@(CoCon con tys args)
- = checkTyApp con_ty tys (mkTyAppMsg e) `thenMaybeL` \ con_tau_ty ->
- -- Note: no call to checkSpecTyApp;
- -- we allow CoCons applied to unboxed types to sail through
- mapMaybeL lintCoreAtom args `thenL` \ maybe_arg_tys ->
- case maybe_arg_tys of
- Nothing -> returnL Nothing
- Just arg_tys -> checkFunApp con_tau_ty arg_tys (mkFunAppMsg con_tau_ty arg_tys e)
- where
- con_ty = getIdUniType con
-
-lintCoreExpr e@(CoPrim op tys args)
- = checkTyApp op_ty tys (mkTyAppMsg e) `thenMaybeL` \ op_tau_ty ->
- -- checkSpecTyApp e tys (mkSpecTyAppMsg e) `thenMaybeL_`
- mapMaybeL lintCoreAtom args `thenL` \ maybe_arg_tys ->
- case maybe_arg_tys of
- Nothing -> returnL Nothing
- Just arg_tys -> checkFunApp op_tau_ty arg_tys (mkFunAppMsg op_tau_ty arg_tys e)
- where
- op_ty = typeOfPrimOp op
+\begin{code}
+lintCoreArgs :: Type -> [CoreArg] -> LintM Type
+lintCoreArgs = lintCoreArgs0 checkTys
-lintCoreExpr e@(CoApp fun arg)
- = lce e []
- where
- lce (CoApp fun arg) arg_tys = lintCoreAtom arg `thenMaybeL` \ arg_ty ->
- lce fun (arg_ty:arg_tys)
+lintCoreArg :: Type -> CoreArg -> LintM Type
+lintCoreArg = lintCoreArg0 checkTys
+\end{code}
- lce other_fun arg_tys = lintCoreExpr other_fun `thenMaybeL` \ fun_ty ->
- checkFunApp fun_ty arg_tys (mkFunAppMsg fun_ty arg_tys e)
+The primitive version of these functions takes a check argument,
+allowing a different comparison.
-lintCoreExpr e@(CoTyApp fun ty_arg)
- = lce e []
- where
- lce (CoTyApp fun ty_arg) ty_args = lce fun (ty_arg:ty_args)
-
- lce other_fun ty_args = lintCoreExpr other_fun `thenMaybeL` \ fun_ty ->
- checkTyApp fun_ty ty_args (mkTyAppMsg e)
- `thenMaybeL` \ res_ty ->
- checkSpecTyApp other_fun ty_args (mkSpecTyAppMsg e)
- `thenMaybeL_`
- returnL (Just res_ty)
-
-lintCoreExpr (CoLam binders expr)
- = ASSERT (not (null binders))
- addLoc (LambdaBodyOf binders) (
- addInScopeVars binders (
- lintCoreExpr expr `thenMaybeL` \ body_ty ->
- returnL (Just (foldr (mkFunTy . getIdUniType) body_ty binders))
- ))
+\begin{code}
+lintCoreArgs0 check_tys ty [] = returnL ty
+lintCoreArgs0 check_tys ty (a : args)
+ = lintCoreArg0 check_tys ty a `thenL` \ res ->
+ lintCoreArgs0 check_tys res args
+
+lintCoreArg0 check_tys ty a@(Type arg_ty)
+ = lintTy arg_ty `seqL`
+ lintTyApp ty arg_ty
+
+lintCoreArg0 check_tys fun_ty arg
+ = -- Make sure function type matches argument
+ lintCoreExpr arg `thenL` \ arg_ty ->
+ let
+ err = mkAppMsg fun_ty arg_ty
+ in
+ case splitFunTy_maybe fun_ty of
+ Just (arg,res) -> check_tys arg arg_ty err `seqL`
+ returnL res
+ _ -> addErrL err
+\end{code}
-lintCoreExpr (CoTyLam tyvar expr)
- = lintCoreExpr expr `thenMaybeL` \ body_ty ->
- case quantifyTy [tyvar] body_ty of
- (_, ty) -> returnL (Just ty) -- not worried about the TyVarTemplates that come back
-
-lintCoreExpr e@(CoCase scrut alts)
- = lintCoreExpr scrut `thenMaybeL` \ scrut_ty ->
-
- -- Check that it is a data type
- case getUniDataTyCon_maybe scrut_ty of
- Nothing -> addErrL (mkCaseDataConMsg e) `thenL_`
- returnL Nothing
- Just (tycon, _, _)
- -> lintCoreAlts alts scrut_ty tycon
-
-lintCoreAlts :: PlainCoreCaseAlternatives
- -> UniType -- Type of scrutinee
- -> TyCon -- TyCon pinned on the case
- -> LintM (Maybe UniType) -- Type of alternatives
-
-lintCoreAlts alts scrut_ty case_tycon
- = (case alts of
- CoAlgAlts alg_alts deflt ->
- chk_prim_type False case_tycon `thenL_`
- chk_non_abstract_type case_tycon `thenL_`
- mapL (lintAlgAlt scrut_ty) alg_alts `thenL` \ maybe_alt_tys ->
- lintDeflt deflt scrut_ty `thenL` \ maybe_deflt_ty ->
- returnL (maybe_deflt_ty : maybe_alt_tys)
-
- CoPrimAlts prim_alts deflt ->
- chk_prim_type True case_tycon `thenL_`
- mapL (lintPrimAlt scrut_ty) prim_alts `thenL` \ maybe_alt_tys ->
- lintDeflt deflt scrut_ty `thenL` \ maybe_deflt_ty ->
- returnL (maybe_deflt_ty : maybe_alt_tys)
- ) `thenL` \ maybe_result_tys ->
- -- Check the result types
- case catMaybes (maybe_result_tys) of
- [] -> returnL Nothing
-
- (first_ty:tys) -> mapL check tys `thenL_`
- returnL (Just first_ty)
- where
- check ty = checkTys first_ty ty (mkCaseAltMsg alts)
- where
- chk_prim_type prim_required tycon
- = if (isPrimTyCon tycon == prim_required) then
- returnL ()
+\begin{code}
+lintTyApp ty arg_ty
+ = case splitForAllTy_maybe ty of
+ Nothing -> addErrL (mkTyAppMsg ty arg_ty)
+
+ Just (tyvar,body) ->
+ if not (isTyVar tyvar) then addErrL (mkTyAppMsg ty arg_ty) else
+ let
+ tyvar_kind = tyVarKind tyvar
+ argty_kind = typeKind arg_ty
+ in
+ if argty_kind `hasMoreBoxityInfo` tyvar_kind
+ -- 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.
+ then
+ returnL (substTyWith [tyvar] [arg_ty] body)
else
- addErrL (mkCasePrimMsg prim_required tycon)
-
- chk_non_abstract_type tycon
- = case (getTyConFamilySize tycon) of
- Nothing -> addErrL (mkCaseAbstractMsg tycon)
- Just _ -> returnL ()
-
-
-lintAlgAlt scrut_ty (con,args,rhs)
- = (case getUniDataTyCon_maybe scrut_ty of
- Nothing ->
- addErrL (mkAlgAltMsg1 scrut_ty)
- Just (tycon, tys_applied, cons) ->
- let
- (_, arg_tys, _) = getInstantiatedDataConSig con tys_applied
- in
- checkL (con `elem` cons) (mkAlgAltMsg2 scrut_ty con) `thenL_`
- checkL (length arg_tys == length args) (mkAlgAltMsg3 con args)
- `thenL_`
- mapL check (arg_tys `zipEqual` args) `thenL_`
- returnL ()
- ) `thenL_`
- addInScopeVars args (
- lintCoreExpr rhs
- )
- where
- check (ty, arg) = checkTys ty (getIdUniType arg) (mkAlgAltMsg4 ty arg)
-
- -- elem: yes, the elem-list here can sometimes be long-ish,
- -- but as it's use-once, probably not worth doing anything different
- -- We give it its own copy, so it isn't overloaded.
- elem _ [] = False
- elem x (y:ys) = x==y || elem x ys
-
-lintPrimAlt scrut_ty alt@(lit,rhs)
- = checkTys (typeOfBasicLit lit) scrut_ty (mkPrimAltMsg alt) `thenL_`
- lintCoreExpr rhs
-
-lintDeflt CoNoDefault scrut_ty = returnL Nothing
-lintDeflt deflt@(CoBindDefault binder rhs) scrut_ty
- = checkTys (getIdUniType binder) scrut_ty (mkDefltMsg deflt) `thenL_`
- addInScopeVars [binder] (
- lintCoreExpr rhs
- )
+ addErrL (mkKindErrMsg tyvar arg_ty)
+
+lintTyApps fun_ty []
+ = returnL fun_ty
+
+lintTyApps fun_ty (arg_ty : arg_tys)
+ = lintTyApp fun_ty arg_ty `thenL` \ fun_ty' ->
+ lintTyApps fun_ty' arg_tys
\end{code}
+
%************************************************************************
%* *
-\subsection[lint-monad]{The Lint monad}
+\subsection[lintCoreAlts]{lintCoreAlts}
%* *
%************************************************************************
\begin{code}
-type LintM a = Bool -- True <=> specialisation has been done
- -> [LintLocInfo] -- Locations
- -> UniqSet Id -- Local vars in scope
- -> Bag ErrMsg -- Error messages so far
- -> (a, Bag ErrMsg) -- Result and error messages (if any)
+checkCaseAlts :: CoreExpr -> Type -> [CoreAlt] -> LintM ()
+-- a) Check that the alts are non-empty
+-- b) Check that the DEFAULT comes first, if it exists
+-- c) Check that there's a default for infinite types
+-- NB: Algebraic cases are not necessarily exhaustive, because
+-- the simplifer correctly eliminates case that can't
+-- possibly match.
+
+checkCaseAlts e ty []
+ = addErrL (mkNullAltsMsg e)
+
+checkCaseAlts e ty alts
+ = checkL (all non_deflt con_alts) (mkNonDefltMsg e) `seqL`
+ checkL (isJust maybe_deflt || not is_infinite_ty)
+ (nonExhaustiveAltsMsg e)
+ where
+ (con_alts, maybe_deflt) = findDefault alts
-type ErrMsg = PprStyle -> Pretty
+ non_deflt (DEFAULT, _, _) = False
+ non_deflt alt = True
-data LintLocInfo
- = RhsOf Id -- The variable bound
- | LambdaBodyOf [Id] -- The lambda-binder
- | BodyOfLetRec [Id] -- One of the binders
- | ImportedUnfolding SrcLoc -- Some imported unfolding (ToDo: say which)
+ is_infinite_ty = case splitTyConApp_maybe ty of
+ Nothing -> False
+ Just (tycon, tycon_arg_tys) -> isPrimTyCon tycon
+\end{code}
+
+\begin{code}
+lintCoreAlt :: Type -- Type of scrutinee
+ -> CoreAlt
+ -> LintM Type -- Type of alternatives
+
+lintCoreAlt scrut_ty alt@(DEFAULT, args, rhs)
+ = checkL (null args) (mkDefaultArgsMsg args) `seqL`
+ lintCoreExpr rhs
+
+lintCoreAlt scrut_ty alt@(LitAlt lit, args, rhs)
+ = checkL (null args) (mkDefaultArgsMsg args) `seqL`
+ checkTys lit_ty scrut_ty
+ (mkBadPatMsg lit_ty scrut_ty) `seqL`
+ lintCoreExpr rhs
+ where
+ lit_ty = literalType lit
-instance Outputable LintLocInfo where
- ppr sty (RhsOf v)
- = ppBesides [ppr sty (getSrcLoc v), ppStr ": [RHS of ", pp_binders sty [v], ppStr "]"]
+lintCoreAlt scrut_ty alt@(DataAlt con, args, rhs)
+ = addLoc (CaseAlt alt) (
- ppr sty (LambdaBodyOf bs)
- = ppBesides [ppr sty (getSrcLoc (head bs)),
- ppStr ": [in body of lambda with binders ", pp_binders sty bs, ppStr "]"]
+ mapL (\arg -> checkL (not (isUnboxedTupleType (idType arg)))
+ (mkUnboxedTupleMsg arg)) args `seqL`
- ppr sty (BodyOfLetRec bs)
- = ppBesides [ppr sty (getSrcLoc (head bs)),
- ppStr ": [in body of letrec with binders ", pp_binders sty bs, ppStr "]"]
+ addInScopeVars args (
- ppr sty (ImportedUnfolding locn)
- = ppBeside (ppr sty locn) (ppStr ": [in an imported unfolding]")
+ -- 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
+ case splitTyConApp scrut_ty of { (tycon, tycon_arg_tys) ->
+ lintTyApps (dataConRepType con) tycon_arg_tys `thenL` \ con_type ->
+ lintCoreArgs con_type (map mk_arg args) `thenL` \ con_result_ty ->
+ checkTys con_result_ty scrut_ty (mkBadPatMsg con_result_ty scrut_ty)
+ } `seqL`
-pp_binders :: PprStyle -> [Id] -> Pretty
-pp_binders sty bs
- = ppInterleave ppComma (map pp_binder bs)
+ -- Check the RHS
+ lintCoreExpr rhs
+ ))
where
- pp_binder b
- = ppCat [ppr sty b, ppStr "::", ppr sty (getIdUniType b)]
+ mk_arg b | isTyVar b = Type (mkTyVarTy b)
+ | isId b = Var b
+ | otherwise = pprPanic "lintCoreAlt:mk_arg " (ppr b)
+\end{code}
+
+%************************************************************************
+%* *
+\subsection[lint-types]{Types}
+%* *
+%************************************************************************
+
+\begin{code}
+lintBinder :: Var -> LintM ()
+lintBinder v = nopL
+-- ToDo: lint its type
+-- ToDo: lint its rules
+
+lintTy :: Type -> LintM ()
+lintTy ty = mapL checkIdInScope (varSetElems (tyVarsOfType ty)) `seqL`
+ returnL ()
+ -- ToDo: check the kind structure of the type
+\end{code}
+
+
+%************************************************************************
+%* *
+\subsection[lint-monad]{The Lint monad}
+%* *
+%************************************************************************
+
+\begin{code}
+type LintM a = [LintLocInfo] -- Locations
+ -> IdSet -- Local vars in scope
+ -> Bag Message -- Error messages so far
+ -> (Maybe a, Bag Message) -- Result and error messages (if any)
+
+data LintLocInfo
+ = RhsOf Id -- The variable bound
+ | LambdaBodyOf Id -- The lambda-binder
+ | BodyOfLetRec [Id] -- One of the binders
+ | CaseAlt CoreAlt -- Pattern of a case alternative
+ | AnExpr CoreExpr -- Some expression
+ | ImportedUnfolding SrcLoc -- Some imported unfolding (ToDo: say which)
\end{code}
\begin{code}
-initL :: LintM a -> Bool -> Maybe ErrMsg
-initL m spec_done
- = case (m spec_done [] emptyUniqSet emptyBag) of { (_, errs) ->
- if isEmptyBag errs then
- Nothing
- else
- Just ( \ sty ->
- ppAboves [ msg sty | msg <- bagToList errs ]
- )
- }
+initL :: LintM a -> Maybe Message {- errors -}
+initL m
+ = case m [] emptyVarSet emptyBag of
+ (_, errs) | isEmptyBag errs -> Nothing
+ | otherwise -> Just (vcat (punctuate (text "") (bagToList errs)))
returnL :: a -> LintM a
-returnL r spec loc scope errs = (r, errs)
+returnL r loc scope errs = (Just r, errs)
+
+nopL :: LintM a
+nopL loc scope errs = (Nothing, errs)
thenL :: LintM a -> (a -> LintM b) -> LintM b
-thenL m k spec loc scope errs
- = case m spec loc scope errs of
- (r, errs') -> k r spec loc scope errs'
-
-thenL_ :: LintM a -> LintM b -> LintM b
-thenL_ m k spec loc scope errs
- = case m spec loc scope errs of
- (_, errs') -> k spec loc scope errs'
-
-thenMaybeL :: LintM (Maybe a) -> (a -> LintM (Maybe b)) -> LintM (Maybe b)
-thenMaybeL m k spec loc scope errs
- = case m spec loc scope errs of
- (Nothing, errs2) -> (Nothing, errs2)
- (Just r, errs2) -> k r spec loc scope errs2
-
-thenMaybeL_ :: LintM (Maybe a) -> LintM (Maybe b) -> LintM (Maybe b)
-thenMaybeL_ m k spec loc scope errs
- = case m spec loc scope errs of
- (Nothing, errs2) -> (Nothing, errs2)
- (Just _, errs2) -> k spec loc scope errs2
+thenL m k loc scope errs
+ = case m loc scope errs of
+ (Just r, errs') -> k r loc scope errs'
+ (Nothing, errs') -> (Nothing, errs')
+
+seqL :: LintM a -> LintM b -> LintM b
+seqL m k loc scope errs
+ = case m loc scope errs of
+ (_, errs') -> k loc scope errs'
mapL :: (a -> LintM b) -> [a] -> LintM [b]
mapL f [] = returnL []
= f x `thenL` \ r ->
mapL f xs `thenL` \ rs ->
returnL (r:rs)
-
-mapMaybeL :: (a -> LintM (Maybe b)) -> [a] -> LintM (Maybe [b])
- -- Returns Nothing if anything fails
-mapMaybeL f [] = returnL (Just [])
-mapMaybeL f (x:xs)
- = f x `thenMaybeL` \ r ->
- mapMaybeL f xs `thenMaybeL` \ rs ->
- returnL (Just (r:rs))
\end{code}
\begin{code}
-checkL :: Bool -> ErrMsg -> LintM ()
-checkL True msg spec loc scope errs = ((), errs)
-checkL False msg spec loc scope errs = ((), addErr errs msg loc)
-
-addErrL :: ErrMsg -> LintM ()
-addErrL msg spec loc scope errs = ((), addErr errs msg loc)
+checkL :: Bool -> Message -> LintM ()
+checkL True msg = nopL
+checkL False msg = addErrL msg
-addErr :: Bag ErrMsg -> ErrMsg -> [LintLocInfo] -> Bag ErrMsg
+addErrL :: Message -> LintM a
+addErrL msg loc scope errs = (Nothing, addErr errs msg loc)
+addErr :: Bag Message -> Message -> [LintLocInfo] -> Bag Message
addErr errs_so_far msg locs
- = ASSERT (not (null locs))
- errs_so_far `snocBag` ( \ sty ->
- ppHang (ppr sty (head locs)) 4 (msg sty)
- )
+ = ASSERT( notNull locs )
+ errs_so_far `snocBag` mk_msg msg
+ where
+ (loc, cxt1) = dumpLoc (head locs)
+ cxts = [snd (dumpLoc loc) | loc <- locs]
+ context | opt_PprStyle_Debug = vcat (reverse cxts) $$ cxt1
+ | otherwise = cxt1
+
+ mk_msg msg = addErrLocHdrLine loc context msg
addLoc :: LintLocInfo -> LintM a -> LintM a
-addLoc extra_loc m spec loc scope errs
- = m spec (extra_loc:loc) scope errs
-
-addInScopeVars :: [Id] -> LintM a -> LintM a
-addInScopeVars ids m spec loc scope errs
- = -- We check if these "new" ids are already
- -- in scope, i.e., we have *shadowing* going on.
- -- For now, it's just a "trace"; we may make
- -- a real error out of it...
- let
- new_set = mkUniqSet ids
+addLoc extra_loc m loc scope errs
+ = m (extra_loc:loc) scope errs
- shadowed = scope `intersectUniqSets` new_set
- in
--- After adding -fliberate-case, Simon decided he likes shadowed
--- names after all. WDP 94/07
--- (if isEmptyUniqSet shadowed
--- then id
--- else pprTrace "Shadowed vars:" (ppr PprDebug (uniqSetToList shadowed))) (
- m spec loc (scope `unionUniqSets` new_set) errs
--- )
+addInScopeVars :: [Var] -> LintM a -> LintM a
+addInScopeVars ids m loc scope errs
+ = m loc (scope `unionVarSet` mkVarSet ids) errs
\end{code}
\begin{code}
-checkTyApp :: UniType
- -> [UniType]
- -> ErrMsg
- -> LintM (Maybe UniType)
-
-checkTyApp forall_ty ty_args msg spec_done loc scope errs
- = if (not spec_done && n_ty_args /= n_tyvars)
- || (spec_done && n_ty_args > n_tyvars)
- --
- -- Things are *not* OK if:
- --
- -- * Unsaturated type app before specialisation has been done;
- --
- -- * Oversaturated type app after specialisation (eta reduction
- -- may well be happening...);
- --
- -- Note: checkTyApp is usually followed by a call to checkSpecTyApp.
- --
- then (Nothing, addErr errs msg loc)
- else (Just res_ty, errs)
- where
- (tyvars, rho_ty) = splitForalls forall_ty
- n_tyvars = length tyvars
- n_ty_args = length ty_args
- leftover_tyvars = drop n_ty_args tyvars
- inst_env = tyvars `zip` ty_args
- res_ty = mkForallTy leftover_tyvars (instantiateTy inst_env rho_ty)
+checkIdInScope :: Var -> LintM ()
+checkIdInScope id
+ = checkInScope (ptext SLIT("is out of scope")) id
+
+checkBndrIdInScope :: Var -> Var -> LintM ()
+checkBndrIdInScope binder id
+ = checkInScope msg id
+ where
+ msg = ptext SLIT("is out of scope inside info for") <+>
+ ppr binder
+
+checkInScope :: SDoc -> Var -> LintM ()
+checkInScope loc_msg var loc scope errs
+ | mustHaveLocalBinding var && not (var `elemVarSet` scope)
+ = (Nothing, addErr errs (hsep [ppr var, loc_msg]) loc)
+ | otherwise
+ = nopL loc scope errs
+
+checkTys :: Type -> Type -> Message -> LintM ()
+-- check ty2 is subtype of ty1 (ie, has same structure but usage
+-- annotations need only be consistent, not equal)
+checkTys ty1 ty2 msg
+ | ty1 `eqType` ty2 = nopL
+ | otherwise = addErrL msg
\end{code}
-\begin{code}
-checkSpecTyApp :: PlainCoreExpr -> [UniType] -> ErrMsg -> LintM (Maybe ())
-
-checkSpecTyApp expr ty_args msg spec_done loc scope errs
- = if spec_done
- && any isUnboxedDataType ty_args
- && not (an_application_of_error expr)
- then (Nothing, addErr errs msg loc)
- else (Just (), errs)
- where
- -- always safe (but maybe unfriendly) to say "False"
- an_application_of_error (CoVar id) | isBottomingId id = True
- an_application_of_error _ = False
-\end{code}
+
+%************************************************************************
+%* *
+\subsection{Error messages}
+%* *
+%************************************************************************
\begin{code}
-checkFunApp :: UniType -- The function type
- -> [UniType] -- The arg type(s)
- -> ErrMsg -- Error messgae
- -> LintM (Maybe UniType) -- The result type
+dumpLoc (RhsOf v)
+ = (getSrcLoc v, brackets (ptext SLIT("RHS of") <+> pp_binders [v]))
-checkFunApp fun_ty arg_tys msg spec loc scope errs
- = cfa res_ty expected_arg_tys arg_tys
- where
- (expected_arg_tys, res_ty) = splitTyArgs fun_ty
+dumpLoc (LambdaBodyOf b)
+ = (getSrcLoc b, brackets (ptext SLIT("in body of lambda with binder") <+> pp_binder b))
- cfa res_ty expected [] -- Args have run out; that's fine
- = (Just (glueTyArgs expected res_ty), errs)
+dumpLoc (BodyOfLetRec [])
+ = (noSrcLoc, brackets (ptext SLIT("In body of a letrec with no binders")))
- cfa res_ty [] arg_tys -- Expected arg tys ran out first; maybe res_ty is a
- -- dictionary type which is actually a function?
- = case splitTyArgs (unDictifyTy res_ty) of
- ([], _) -> (Nothing, addErr errs msg loc) -- Too many args
- (new_expected, new_res) -> cfa new_res new_expected arg_tys
+dumpLoc (BodyOfLetRec bs@(_:_))
+ = ( getSrcLoc (head bs), brackets (ptext SLIT("in body of letrec with binders") <+> pp_binders bs))
- cfa res_ty (expected_arg_ty:expected_arg_tys) (arg_ty:arg_tys)
- = case (cmpUniType True{-properly-} expected_arg_ty arg_ty) of
- EQ_ -> cfa res_ty expected_arg_tys arg_tys
- other -> (Nothing, addErr errs msg loc) -- Arg mis-match
-\end{code}
+dumpLoc (AnExpr e)
+ = (noSrcLoc, text "In the expression:" <+> ppr e)
-\begin{code}
-checkInScope :: Id -> LintM ()
-checkInScope id spec loc scope errs
- = if isLocallyDefined id && not (id `elementOfUniqSet` scope) then
- ((), addErr errs (\ sty -> ppCat [ppr sty id, ppStr "is out of scope"]) loc)
- else
- ((), errs)
-
-checkTys :: UniType -> UniType -> ErrMsg -> LintM ()
-checkTys ty1 ty2 msg spec loc scope errs
- = case (cmpUniType True{-properly-} ty1 ty2) of
- EQ_ -> ((), errs)
- other -> ((), addErr errs msg loc)
-\end{code}
+dumpLoc (CaseAlt (con, args, rhs))
+ = (noSrcLoc, text "In a case pattern:" <+> parens (ppr con <+> ppr args))
-\begin{code}
-mkCaseAltMsg :: PlainCoreCaseAlternatives -> ErrMsg
-mkCaseAltMsg alts sty
- = ppAbove (ppStr "In some case alternatives, type of alternatives not all same:")
- (ppr sty alts)
-
-mkCaseDataConMsg :: PlainCoreExpr -> ErrMsg
-mkCaseDataConMsg expr sty
- = ppAbove (ppStr "A case scrutinee not a type-constructor type:")
- (pp_expr sty expr)
-
-mkCasePrimMsg :: Bool -> TyCon -> ErrMsg
-mkCasePrimMsg True tycon sty
- = ppAbove (ppStr "A primitive case on a non-primitive type:")
- (ppr sty tycon)
-mkCasePrimMsg False tycon sty
- = ppAbove (ppStr "An algebraic case on a primitive type:")
- (ppr sty tycon)
-
-mkCaseAbstractMsg :: TyCon -> ErrMsg
-mkCaseAbstractMsg tycon sty
- = ppAbove (ppStr "An algebraic case on an abstract type:")
- (ppr sty tycon)
-
-mkDefltMsg :: PlainCoreCaseDefault -> ErrMsg
-mkDefltMsg deflt sty
- = ppAbove (ppStr "Binder in default case of a case expression doesn't match type of scrutinee:")
- (ppr sty deflt)
-
-mkFunAppMsg :: UniType -> [UniType] -> PlainCoreExpr -> ErrMsg
-mkFunAppMsg fun_ty arg_tys expr sty
- = ppAboves [ppStr "In a function application, function type doesn't match arg types:",
- ppHang (ppStr "Function type:") 4 (ppr sty fun_ty),
- ppHang (ppStr "Arg types:") 4 (ppAboves (map (ppr sty) arg_tys)),
- ppHang (ppStr "Expression:") 4 (pp_expr sty expr)]
-
-mkUnappTyMsg :: Id -> UniType -> ErrMsg
-mkUnappTyMsg var ty sty
- = ppAboves [ppStr "Variable has a for-all type, but isn't applied to any types.",
- ppBeside (ppStr "Var: ") (ppr sty var),
- ppBeside (ppStr "Its type: ") (ppr sty ty)]
-
-mkAlgAltMsg1 :: UniType -> ErrMsg
-mkAlgAltMsg1 ty sty
- = ppAbove (ppStr "In some case statement, type of scrutinee is not a data type:")
- (ppr sty ty)
-
-mkAlgAltMsg2 :: UniType -> Id -> ErrMsg
-mkAlgAltMsg2 ty con sty
- = ppAboves [
- ppStr "In some algebraic case alternative, constructor is not a constructor of scrutinee type:",
- ppr sty ty,
- ppr sty con
- ]
+dumpLoc (ImportedUnfolding locn)
+ = (locn, brackets (ptext SLIT("in an imported unfolding")))
-mkAlgAltMsg3 :: Id -> [Id] -> ErrMsg
-mkAlgAltMsg3 con alts sty
- = ppAboves [
- ppStr "In some algebraic case alternative, number of arguments doesn't match constructor:",
- ppr sty con,
- ppr sty alts
- ]
+pp_binders :: [Var] -> SDoc
+pp_binders bs = sep (punctuate comma (map pp_binder bs))
-mkAlgAltMsg4 :: UniType -> Id -> ErrMsg
-mkAlgAltMsg4 ty arg sty
- = ppAboves [
- ppStr "In some algebraic case alternative, type of argument doesn't match data constructor:",
- ppr sty ty,
- ppr sty arg
- ]
+pp_binder :: Var -> SDoc
+pp_binder b | isId b = hsep [ppr b, dcolon, ppr (idType b)]
+ | isTyVar b = hsep [ppr b, dcolon, ppr (tyVarKind b)]
+\end{code}
-mkPrimAltMsg :: (BasicLit, PlainCoreExpr) -> ErrMsg
-mkPrimAltMsg alt sty
- = ppAbove (ppStr "In a primitive case alternative, type of literal doesn't match type of scrutinee:")
- (ppr sty alt)
-
-mkRhsMsg :: Id -> UniType -> ErrMsg
-mkRhsMsg binder ty sty
- = ppAboves [ppCat [ppStr "The type of this binder doesn't match the type of its RHS:",
- ppr sty binder],
- ppCat [ppStr "Binder's type:", ppr sty (getIdUniType binder)],
- ppCat [ppStr "Rhs type:", ppr sty ty]
- ]
+\begin{code}
+------------------------------------------------------
+-- Messages for case expressions
+
+mkNullAltsMsg :: CoreExpr -> Message
+mkNullAltsMsg e
+ = hang (text "Case expression with no alternatives:")
+ 4 (ppr e)
+
+mkDefaultArgsMsg :: [Var] -> Message
+mkDefaultArgsMsg args
+ = hang (text "DEFAULT case with binders")
+ 4 (ppr args)
+
+mkCaseAltMsg :: CoreExpr -> Message
+mkCaseAltMsg e
+ = hang (text "Type of case alternatives not the same:")
+ 4 (ppr e)
+
+mkScrutMsg :: Id -> Type -> Message
+mkScrutMsg var scrut_ty
+ = vcat [text "Result binder in case doesn't match scrutinee:" <+> ppr var,
+ text "Result binder type:" <+> ppr (idType var),
+ text "Scrutinee type:" <+> ppr scrut_ty]
+
+
+mkNonDefltMsg e
+ = hang (text "Case expression with DEFAULT not at the beginnning") 4 (ppr e)
+
+nonExhaustiveAltsMsg :: CoreExpr -> Message
+nonExhaustiveAltsMsg e
+ = hang (text "Case expression with non-exhaustive alternatives") 4 (ppr e)
+
+mkBadPatMsg :: Type -> Type -> Message
+mkBadPatMsg con_result_ty scrut_ty
+ = vcat [
+ text "In a case alternative, pattern result type doesn't match scrutinee type:",
+ text "Pattern result type:" <+> ppr con_result_ty,
+ text "Scrutinee type:" <+> ppr scrut_ty
+ ]
-mkRhsPrimMsg :: Id -> PlainCoreExpr -> ErrMsg
-mkRhsPrimMsg binder rhs sty
- = ppAboves [ppCat [ppStr "The type of this binder is primitive:",
- ppr sty binder],
- ppCat [ppStr "Binder's type:", ppr sty (getIdUniType binder)]
+------------------------------------------------------
+-- Other error messages
+
+mkAppMsg :: Type -> Type -> Message
+mkAppMsg fun arg
+ = vcat [ptext SLIT("Argument value doesn't match argument type:"),
+ hang (ptext SLIT("Fun type:")) 4 (ppr fun),
+ hang (ptext SLIT("Arg type:")) 4 (ppr arg)]
+
+mkKindErrMsg :: TyVar -> Type -> Message
+mkKindErrMsg tyvar arg_ty
+ = 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:"))
+ 4 (ppr arg_ty <+> dcolon <+> ppr (typeKind arg_ty))]
+
+mkTyAppMsg :: Type -> Type -> Message
+mkTyAppMsg ty arg_ty
+ = vcat [text "Illegal type application:",
+ hang (ptext SLIT("Exp type:"))
+ 4 (ppr ty <+> dcolon <+> ppr (typeKind ty)),
+ 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:"),
+ ppr binder],
+ 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:"),
+ ppr binder],
+ hsep [ptext SLIT("Binder's type:"), ppr (idType binder)]
]
-mkTyAppMsg :: PlainCoreExpr -> ErrMsg
-mkTyAppMsg expr sty
- = ppAboves [ppStr "In a type application, either the function's type doesn't match",
- ppStr "the argument types, or an argument type is primitive:",
- pp_expr sty expr]
+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)]]
-mkSpecTyAppMsg :: PlainCoreExpr -> ErrMsg
-mkSpecTyAppMsg expr sty
- = ppAbove (ppStr "Unboxed types in a type application (after specialisation):")
- (pp_expr sty expr)
+mkCoerceErr from_ty expr_ty
+ = vcat [ptext SLIT("From-type of Coerce differs from type of enclosed expression"),
+ ptext SLIT("From-type:") <+> ppr from_ty,
+ ptext SLIT("Type of enclosed expr:") <+> ppr expr_ty
+ ]
-pp_expr sty expr
- = pprCoreExpr sty pprBigCoreBinder pprTypedCoreBinder pprTypedCoreBinder expr
+mkStrangeTyMsg e
+ = ptext SLIT("Type where expression expected:") <+> ppr e
\end{code}
projects / ghc-hetmet.git / blobdiff