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Diffstat (limited to 'compiler/rename/RnBinds.lhs')
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diff --git a/compiler/rename/RnBinds.lhs b/compiler/rename/RnBinds.lhs new file mode 100644 index 0000000000..13035e72e2 --- /dev/null +++ b/compiler/rename/RnBinds.lhs @@ -0,0 +1,660 @@ +% +% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998 +% +\section[RnBinds]{Renaming and dependency analysis of bindings} + +This module does renaming and dependency analysis on value bindings in +the abstract syntax. It does {\em not} do cycle-checks on class or +type-synonym declarations; those cannot be done at this stage because +they may be affected by renaming (which isn't fully worked out yet). + +\begin{code} +module RnBinds ( + rnTopBinds, + rnLocalBindsAndThen, rnValBindsAndThen, rnValBinds, trimWith, + rnMethodBinds, renameSigs, + rnMatchGroup, rnGRHSs + ) where + +#include "HsVersions.h" + +import {-# SOURCE #-} RnExpr( rnLExpr, rnStmts ) + +import HsSyn +import RdrHsSyn +import RnHsSyn +import TcRnMonad +import RnTypes ( rnHsSigType, rnLHsType, rnHsTypeFVs, + rnLPat, rnPatsAndThen, patSigErr, checkPrecMatch ) +import RnEnv ( bindLocatedLocalsRn, lookupLocatedBndrRn, + lookupLocatedInstDeclBndr, newIPNameRn, + lookupLocatedSigOccRn, bindPatSigTyVars, bindPatSigTyVarsFV, + bindLocalFixities, bindSigTyVarsFV, + warnUnusedLocalBinds, mapFvRn, extendTyVarEnvFVRn, + ) +import DynFlags ( DynFlag(..) ) +import Name ( Name, nameOccName, nameSrcLoc ) +import NameEnv +import NameSet +import PrelNames ( isUnboundName ) +import RdrName ( RdrName, rdrNameOcc ) +import SrcLoc ( mkSrcSpan, Located(..), unLoc ) +import ListSetOps ( findDupsEq ) +import BasicTypes ( RecFlag(..) ) +import Digraph ( SCC(..), stronglyConnComp ) +import Bag +import Outputable +import Maybes ( orElse, isJust ) +import Util ( filterOut ) +import Monad ( foldM ) +\end{code} + +-- ToDo: Put the annotations into the monad, so that they arrive in the proper +-- place and can be used when complaining. + +The code tree received by the function @rnBinds@ contains definitions +in where-clauses which are all apparently mutually recursive, but which may +not really depend upon each other. For example, in the top level program +\begin{verbatim} +f x = y where a = x + y = x +\end{verbatim} +the definitions of @a@ and @y@ do not depend on each other at all. +Unfortunately, the typechecker cannot always check such definitions. +\footnote{Mycroft, A. 1984. Polymorphic type schemes and recursive +definitions. In Proceedings of the International Symposium on Programming, +Toulouse, pp. 217-39. LNCS 167. Springer Verlag.} +However, the typechecker usually can check definitions in which only the +strongly connected components have been collected into recursive bindings. +This is precisely what the function @rnBinds@ does. + +ToDo: deal with case where a single monobinds binds the same variable +twice. + +The vertag tag is a unique @Int@; the tags only need to be unique +within one @MonoBinds@, so that unique-Int plumbing is done explicitly +(heavy monad machinery not needed). + + +%************************************************************************ +%* * +%* naming conventions * +%* * +%************************************************************************ + +\subsection[name-conventions]{Name conventions} + +The basic algorithm involves walking over the tree and returning a tuple +containing the new tree plus its free variables. Some functions, such +as those walking polymorphic bindings (HsBinds) and qualifier lists in +list comprehensions (@Quals@), return the variables bound in local +environments. These are then used to calculate the free variables of the +expression evaluated in these environments. + +Conventions for variable names are as follows: +\begin{itemize} +\item +new code is given a prime to distinguish it from the old. + +\item +a set of variables defined in @Exp@ is written @dvExp@ + +\item +a set of variables free in @Exp@ is written @fvExp@ +\end{itemize} + +%************************************************************************ +%* * +%* analysing polymorphic bindings (HsBindGroup, HsBind) +%* * +%************************************************************************ + +\subsubsection[dep-HsBinds]{Polymorphic bindings} + +Non-recursive expressions are reconstructed without any changes at top +level, although their component expressions may have to be altered. +However, non-recursive expressions are currently not expected as +\Haskell{} programs, and this code should not be executed. + +Monomorphic bindings contain information that is returned in a tuple +(a @FlatMonoBinds@) containing: + +\begin{enumerate} +\item +a unique @Int@ that serves as the ``vertex tag'' for this binding. + +\item +the name of a function or the names in a pattern. These are a set +referred to as @dvLhs@, the defined variables of the left hand side. + +\item +the free variables of the body. These are referred to as @fvBody@. + +\item +the definition's actual code. This is referred to as just @code@. +\end{enumerate} + +The function @nonRecDvFv@ returns two sets of variables. The first is +the set of variables defined in the set of monomorphic bindings, while the +second is the set of free variables in those bindings. + +The set of variables defined in a non-recursive binding is just the +union of all of them, as @union@ removes duplicates. However, the +free variables in each successive set of cumulative bindings is the +union of those in the previous set plus those of the newest binding after +the defined variables of the previous set have been removed. + +@rnMethodBinds@ deals only with the declarations in class and +instance declarations. It expects only to see @FunMonoBind@s, and +it expects the global environment to contain bindings for the binders +(which are all class operations). + +%************************************************************************ +%* * +\subsubsection{ Top-level bindings} +%* * +%************************************************************************ + +@rnTopMonoBinds@ assumes that the environment already +contains bindings for the binders of this particular binding. + +\begin{code} +rnTopBinds :: HsValBinds RdrName -> RnM (HsValBinds Name, DefUses) + +-- The binders of the binding are in scope already; +-- the top level scope resolution does that + +rnTopBinds binds + = do { is_boot <- tcIsHsBoot + ; if is_boot then rnTopBindsBoot binds + else rnTopBindsSrc binds } + +rnTopBindsBoot :: HsValBinds RdrName -> RnM (HsValBinds Name, DefUses) +-- A hs-boot file has no bindings. +-- Return a single HsBindGroup with empty binds and renamed signatures +rnTopBindsBoot (ValBindsIn mbinds sigs) + = do { checkErr (isEmptyLHsBinds mbinds) (bindsInHsBootFile mbinds) + ; sigs' <- renameSigs okHsBootSig sigs + ; return (ValBindsOut [] sigs', usesOnly (hsSigsFVs sigs')) } + +rnTopBindsSrc :: HsValBinds RdrName -> RnM (HsValBinds Name, DefUses) +rnTopBindsSrc binds@(ValBindsIn mbinds _) + = do { (binds', dus) <- rnValBinds noTrim binds + + -- Warn about missing signatures, + ; let { ValBindsOut _ sigs' = binds' + ; ty_sig_vars = mkNameSet [ unLoc n | L _ (TypeSig n _) <- sigs'] + ; un_sigd_bndrs = duDefs dus `minusNameSet` ty_sig_vars } + + ; warn_missing_sigs <- doptM Opt_WarnMissingSigs + ; ifM (warn_missing_sigs) + (mappM_ missingSigWarn (nameSetToList un_sigd_bndrs)) + + ; return (binds', dus) + } +\end{code} + + + +%********************************************************* +%* * + HsLocalBinds +%* * +%********************************************************* + +\begin{code} +rnLocalBindsAndThen + :: HsLocalBinds RdrName + -> (HsLocalBinds Name -> RnM (result, FreeVars)) + -> RnM (result, FreeVars) +-- This version (a) assumes that the binding vars are not already in scope +-- (b) removes the binders from the free vars of the thing inside +-- The parser doesn't produce ThenBinds +rnLocalBindsAndThen EmptyLocalBinds thing_inside + = thing_inside EmptyLocalBinds + +rnLocalBindsAndThen (HsValBinds val_binds) thing_inside + = rnValBindsAndThen val_binds $ \ val_binds' -> + thing_inside (HsValBinds val_binds') + +rnLocalBindsAndThen (HsIPBinds binds) thing_inside + = rnIPBinds binds `thenM` \ (binds',fv_binds) -> + thing_inside (HsIPBinds binds') `thenM` \ (thing, fvs_thing) -> + returnM (thing, fvs_thing `plusFV` fv_binds) + +------------- +rnIPBinds (IPBinds ip_binds _no_dict_binds) + = do { (ip_binds', fvs_s) <- mapAndUnzipM (wrapLocFstM rnIPBind) ip_binds + ; return (IPBinds ip_binds' emptyLHsBinds, plusFVs fvs_s) } + +rnIPBind (IPBind n expr) + = newIPNameRn n `thenM` \ name -> + rnLExpr expr `thenM` \ (expr',fvExpr) -> + return (IPBind name expr', fvExpr) +\end{code} + + +%************************************************************************ +%* * + ValBinds +%* * +%************************************************************************ + +\begin{code} +rnValBindsAndThen :: HsValBinds RdrName + -> (HsValBinds Name -> RnM (result, FreeVars)) + -> RnM (result, FreeVars) + +rnValBindsAndThen binds@(ValBindsIn mbinds sigs) thing_inside + = -- Extract all the binders in this group, and extend the + -- current scope, inventing new names for the new binders + -- This also checks that the names form a set + bindLocatedLocalsRn doc mbinders_w_srclocs $ \ bndrs -> + + -- Then install local fixity declarations + -- Notice that they scope over thing_inside too + bindLocalFixities [sig | L _ (FixSig sig) <- sigs ] $ + + -- Do the business + rnValBinds (trimWith bndrs) binds `thenM` \ (binds, bind_dus) -> + + -- Now do the "thing inside" + thing_inside binds `thenM` \ (result,result_fvs) -> + + -- Final error checking + let + all_uses = duUses bind_dus `plusFV` result_fvs + -- duUses: It's important to return all the uses, not the 'real uses' + -- used for warning about unused bindings. Otherwise consider: + -- x = 3 + -- y = let p = x in 'x' -- NB: p not used + -- If we don't "see" the dependency of 'y' on 'x', we may put the + -- bindings in the wrong order, and the type checker will complain + -- that x isn't in scope + + unused_bndrs = [ b | b <- bndrs, not (b `elemNameSet` all_uses)] + in + warnUnusedLocalBinds unused_bndrs `thenM_` + + returnM (result, delListFromNameSet all_uses bndrs) + where + mbinders_w_srclocs = collectHsBindLocatedBinders mbinds + doc = text "In the binding group for:" + <+> pprWithCommas ppr (map unLoc mbinders_w_srclocs) + +--------------------- +rnValBinds :: (FreeVars -> FreeVars) + -> HsValBinds RdrName + -> RnM (HsValBinds Name, DefUses) +-- Assumes the binders of the binding are in scope already + +rnValBinds trim (ValBindsIn mbinds sigs) + = do { sigs' <- rename_sigs sigs + + ; binds_w_dus <- mapBagM (rnBind (mkSigTvFn sigs') trim) mbinds + + ; let (binds', bind_dus) = depAnalBinds binds_w_dus + + -- We do the check-sigs after renaming the bindings, + -- so that we have convenient access to the binders + ; check_sigs (okBindSig (duDefs bind_dus)) sigs' + + ; return (ValBindsOut binds' sigs', + usesOnly (hsSigsFVs sigs') `plusDU` bind_dus) } + + +--------------------- +depAnalBinds :: Bag (LHsBind Name, [Name], Uses) + -> ([(RecFlag, LHsBinds Name)], DefUses) +-- Dependency analysis; this is important so that +-- unused-binding reporting is accurate +depAnalBinds binds_w_dus + = (map get_binds sccs, map get_du sccs) + where + sccs = stronglyConnComp edges + + keyd_nodes = bagToList binds_w_dus `zip` [0::Int ..] + + edges = [ (node, key, [key | n <- nameSetToList uses, + Just key <- [lookupNameEnv key_map n] ]) + | (node@(_,_,uses), key) <- keyd_nodes ] + + key_map :: NameEnv Int -- Which binding it comes from + key_map = mkNameEnv [(bndr, key) | ((_, bndrs, _), key) <- keyd_nodes + , bndr <- bndrs ] + + get_binds (AcyclicSCC (bind, _, _)) = (NonRecursive, unitBag bind) + get_binds (CyclicSCC binds_w_dus) = (Recursive, listToBag [b | (b,d,u) <- binds_w_dus]) + + get_du (AcyclicSCC (_, bndrs, uses)) = (Just (mkNameSet bndrs), uses) + get_du (CyclicSCC binds_w_dus) = (Just defs, uses) + where + defs = mkNameSet [b | (_,bs,_) <- binds_w_dus, b <- bs] + uses = unionManyNameSets [u | (_,_,u) <- binds_w_dus] + + +--------------------- +-- Bind the top-level forall'd type variables in the sigs. +-- E.g f :: a -> a +-- f = rhs +-- The 'a' scopes over the rhs +-- +-- NB: there'll usually be just one (for a function binding) +-- but if there are many, one may shadow the rest; too bad! +-- e.g x :: [a] -> [a] +-- y :: [(a,a)] -> a +-- (x,y) = e +-- In e, 'a' will be in scope, and it'll be the one from 'y'! + +mkSigTvFn :: [LSig Name] -> (Name -> [Name]) +-- Return a lookup function that maps an Id Name to the names +-- of the type variables that should scope over its body.. +mkSigTvFn sigs + = \n -> lookupNameEnv env n `orElse` [] + where + env :: NameEnv [Name] + env = mkNameEnv [ (name, map hsLTyVarName ltvs) + | L _ (TypeSig (L _ name) + (L _ (HsForAllTy Explicit ltvs _ _))) <- sigs] + -- Note the pattern-match on "Explicit"; we only bind + -- type variables from signatures with an explicit top-level for-all + +-- The trimming function trims the free vars we attach to a +-- binding so that it stays reasonably small +noTrim :: FreeVars -> FreeVars +noTrim fvs = fvs -- Used at top level + +trimWith :: [Name] -> FreeVars -> FreeVars +-- Nested bindings; trim by intersection with the names bound here +trimWith bndrs = intersectNameSet (mkNameSet bndrs) + +--------------------- +rnBind :: (Name -> [Name]) -- Signature tyvar function + -> (FreeVars -> FreeVars) -- Trimming function for rhs free vars + -> LHsBind RdrName + -> RnM (LHsBind Name, [Name], Uses) +rnBind sig_fn trim (L loc (PatBind { pat_lhs = pat, pat_rhs = grhss })) + = setSrcSpan loc $ + do { (pat', pat_fvs) <- rnLPat pat + + ; let bndrs = collectPatBinders pat' + + ; (grhss', fvs) <- bindSigTyVarsFV (concatMap sig_fn bndrs) $ + rnGRHSs PatBindRhs grhss + + ; return (L loc (PatBind { pat_lhs = pat', pat_rhs = grhss', + pat_rhs_ty = placeHolderType, bind_fvs = trim fvs }), + bndrs, pat_fvs `plusFV` fvs) } + +rnBind sig_fn trim (L loc (FunBind { fun_id = name, fun_infix = inf, fun_matches = matches })) + = setSrcSpan loc $ + do { new_name <- lookupLocatedBndrRn name + ; let plain_name = unLoc new_name + + ; (matches', fvs) <- bindSigTyVarsFV (sig_fn plain_name) $ + rnMatchGroup (FunRhs plain_name) matches + + ; checkPrecMatch inf plain_name matches' + + ; return (L loc (FunBind { fun_id = new_name, fun_infix = inf, fun_matches = matches', + bind_fvs = trim fvs, fun_co_fn = idCoercion }), + [plain_name], fvs) + } +\end{code} + + +@rnMethodBinds@ is used for the method bindings of a class and an instance +declaration. Like @rnBinds@ but without dependency analysis. + +NOTA BENE: we record each {\em binder} of a method-bind group as a free variable. +That's crucial when dealing with an instance decl: +\begin{verbatim} + instance Foo (T a) where + op x = ... +\end{verbatim} +This might be the {\em sole} occurrence of @op@ for an imported class @Foo@, +and unless @op@ occurs we won't treat the type signature of @op@ in the class +decl for @Foo@ as a source of instance-decl gates. But we should! Indeed, +in many ways the @op@ in an instance decl is just like an occurrence, not +a binder. + +\begin{code} +rnMethodBinds :: Name -- Class name + -> [Name] -- Names for generic type variables + -> LHsBinds RdrName + -> RnM (LHsBinds Name, FreeVars) + +rnMethodBinds cls gen_tyvars binds + = foldM do_one (emptyBag,emptyFVs) (bagToList binds) + where do_one (binds,fvs) bind = do + (bind', fvs_bind) <- rnMethodBind cls gen_tyvars bind + return (bind' `unionBags` binds, fvs_bind `plusFV` fvs) + +rnMethodBind cls gen_tyvars (L loc (FunBind { fun_id = name, fun_infix = inf, + fun_matches = MatchGroup matches _ })) + = setSrcSpan loc $ + lookupLocatedInstDeclBndr cls name `thenM` \ sel_name -> + let plain_name = unLoc sel_name in + -- We use the selector name as the binder + + mapFvRn (rn_match plain_name) matches `thenM` \ (new_matches, fvs) -> + let + new_group = MatchGroup new_matches placeHolderType + in + checkPrecMatch inf plain_name new_group `thenM_` + returnM (unitBag (L loc (FunBind { fun_id = sel_name, fun_infix = inf, fun_matches = new_group, + bind_fvs = fvs, fun_co_fn = idCoercion })), + fvs `addOneFV` plain_name) + -- The 'fvs' field isn't used for method binds + where + -- Truly gruesome; bring into scope the correct members of the generic + -- type variables. See comments in RnSource.rnSourceDecl(ClassDecl) + rn_match sel_name match@(L _ (Match (L _ (TypePat ty) : _) _ _)) + = extendTyVarEnvFVRn gen_tvs $ + rnMatch (FunRhs sel_name) match + where + tvs = map (rdrNameOcc.unLoc) (extractHsTyRdrTyVars ty) + gen_tvs = [tv | tv <- gen_tyvars, nameOccName tv `elem` tvs] + + rn_match sel_name match = rnMatch (FunRhs sel_name) match + + +-- Can't handle method pattern-bindings which bind multiple methods. +rnMethodBind cls gen_tyvars mbind@(L loc (PatBind other_pat _ _ _)) + = addLocErr mbind methodBindErr `thenM_` + returnM (emptyBag, emptyFVs) +\end{code} + + +%************************************************************************ +%* * +\subsubsection[dep-Sigs]{Signatures (and user-pragmas for values)} +%* * +%************************************************************************ + +@renameSigs@ checks for: +\begin{enumerate} +\item more than one sig for one thing; +\item signatures given for things not bound here; +\item with suitably flaggery, that all top-level things have type signatures. +\end{enumerate} +% +At the moment we don't gather free-var info from the types in +signatures. We'd only need this if we wanted to report unused tyvars. + +\begin{code} +renameSigs :: (LSig Name -> Bool) -> [LSig RdrName] -> RnM [LSig Name] +-- Renames the signatures and performs error checks +renameSigs ok_sig sigs + = do { sigs' <- rename_sigs sigs + ; check_sigs ok_sig sigs' + ; return sigs' } + +---------------------- +rename_sigs :: [LSig RdrName] -> RnM [LSig Name] +rename_sigs sigs = mappM (wrapLocM renameSig) + (filter (not . isFixityLSig) sigs) + -- Remove fixity sigs which have been dealt with already + +---------------------- +check_sigs :: (LSig Name -> Bool) -> [LSig Name] -> RnM () +-- Used for class and instance decls, as well as regular bindings +check_sigs ok_sig sigs + -- Check for (a) duplicate signatures + -- (b) signatures for things not in this group + = do { mappM_ unknownSigErr (filter (not . ok_sig) sigs') + ; mappM_ dupSigDeclErr (findDupsEq eqHsSig sigs') } + where + -- Don't complain about an unbound name again + sigs' = filterOut bad_name sigs + bad_name sig = case sigName sig of + Just n -> isUnboundName n + other -> False + +-- We use lookupLocatedSigOccRn in the signatures, which is a little bit unsatisfactory +-- because this won't work for: +-- instance Foo T where +-- {-# INLINE op #-} +-- Baz.op = ... +-- We'll just rename the INLINE prag to refer to whatever other 'op' +-- is in scope. (I'm assuming that Baz.op isn't in scope unqualified.) +-- Doesn't seem worth much trouble to sort this. + +renameSig :: Sig RdrName -> RnM (Sig Name) +-- FixitSig is renamed elsewhere. +renameSig (TypeSig v ty) + = lookupLocatedSigOccRn v `thenM` \ new_v -> + rnHsSigType (quotes (ppr v)) ty `thenM` \ new_ty -> + returnM (TypeSig new_v new_ty) + +renameSig (SpecInstSig ty) + = rnLHsType (text "A SPECIALISE instance pragma") ty `thenM` \ new_ty -> + returnM (SpecInstSig new_ty) + +renameSig (SpecSig v ty inl) + = lookupLocatedSigOccRn v `thenM` \ new_v -> + rnHsSigType (quotes (ppr v)) ty `thenM` \ new_ty -> + returnM (SpecSig new_v new_ty inl) + +renameSig (InlineSig v s) + = lookupLocatedSigOccRn v `thenM` \ new_v -> + returnM (InlineSig new_v s) +\end{code} + + +************************************************************************ +* * +\subsection{Match} +* * +************************************************************************ + +\begin{code} +rnMatchGroup :: HsMatchContext Name -> MatchGroup RdrName -> RnM (MatchGroup Name, FreeVars) +rnMatchGroup ctxt (MatchGroup ms _) + = mapFvRn (rnMatch ctxt) ms `thenM` \ (new_ms, ms_fvs) -> + returnM (MatchGroup new_ms placeHolderType, ms_fvs) + +rnMatch :: HsMatchContext Name -> LMatch RdrName -> RnM (LMatch Name, FreeVars) +rnMatch ctxt = wrapLocFstM (rnMatch' ctxt) + +rnMatch' ctxt match@(Match pats maybe_rhs_sig grhss) + = + -- Deal with the rhs type signature + bindPatSigTyVarsFV rhs_sig_tys $ + doptM Opt_GlasgowExts `thenM` \ opt_GlasgowExts -> + (case maybe_rhs_sig of + Nothing -> returnM (Nothing, emptyFVs) + Just ty | opt_GlasgowExts -> rnHsTypeFVs doc_sig ty `thenM` \ (ty', ty_fvs) -> + returnM (Just ty', ty_fvs) + | otherwise -> addLocErr ty patSigErr `thenM_` + returnM (Nothing, emptyFVs) + ) `thenM` \ (maybe_rhs_sig', ty_fvs) -> + + -- Now the main event + rnPatsAndThen ctxt pats $ \ pats' -> + rnGRHSs ctxt grhss `thenM` \ (grhss', grhss_fvs) -> + + returnM (Match pats' maybe_rhs_sig' grhss', grhss_fvs `plusFV` ty_fvs) + -- The bindPatSigTyVarsFV and rnPatsAndThen will remove the bound FVs + where + rhs_sig_tys = case maybe_rhs_sig of + Nothing -> [] + Just ty -> [ty] + doc_sig = text "In a result type-signature" +\end{code} + + +%************************************************************************ +%* * +\subsubsection{Guarded right-hand sides (GRHSs)} +%* * +%************************************************************************ + +\begin{code} +rnGRHSs :: HsMatchContext Name -> GRHSs RdrName -> RnM (GRHSs Name, FreeVars) + +rnGRHSs ctxt (GRHSs grhss binds) + = rnLocalBindsAndThen binds $ \ binds' -> + mapFvRn (rnGRHS ctxt) grhss `thenM` \ (grhss', fvGRHSs) -> + returnM (GRHSs grhss' binds', fvGRHSs) + +rnGRHS :: HsMatchContext Name -> LGRHS RdrName -> RnM (LGRHS Name, FreeVars) +rnGRHS ctxt = wrapLocFstM (rnGRHS' ctxt) + +rnGRHS' ctxt (GRHS guards rhs) + = do { opt_GlasgowExts <- doptM Opt_GlasgowExts + ; ((guards', rhs'), fvs) <- rnStmts (PatGuard ctxt) guards $ + rnLExpr rhs + + ; checkM (opt_GlasgowExts || is_standard_guard guards') + (addWarn (nonStdGuardErr guards')) + + ; return (GRHS guards' rhs', fvs) } + where + -- Standard Haskell 1.4 guards are just a single boolean + -- expression, rather than a list of qualifiers as in the + -- Glasgow extension + is_standard_guard [] = True + is_standard_guard [L _ (ExprStmt _ _ _)] = True + is_standard_guard other = False +\end{code} + +%************************************************************************ +%* * +\subsection{Error messages} +%* * +%************************************************************************ + +\begin{code} +dupSigDeclErr sigs@(L loc sig : _) + = addErrAt loc $ + vcat [ptext SLIT("Duplicate") <+> what_it_is <> colon, + nest 2 (vcat (map ppr_sig sigs))] + where + what_it_is = hsSigDoc sig + ppr_sig (L loc sig) = ppr loc <> colon <+> ppr sig + +unknownSigErr (L loc sig) + = addErrAt loc $ + sep [ptext SLIT("Misplaced") <+> what_it_is <> colon, ppr sig] + where + what_it_is = hsSigDoc sig + +missingSigWarn var + = addWarnAt (mkSrcSpan loc loc) $ + sep [ptext SLIT("Definition but no type signature for"), quotes (ppr var)] + where + loc = nameSrcLoc var -- TODO: make a proper span + +methodBindErr mbind + = hang (ptext SLIT("Pattern bindings (except simple variables) not allowed in instance declarations")) + 2 (ppr mbind) + +bindsInHsBootFile mbinds + = hang (ptext SLIT("Bindings in hs-boot files are not allowed")) + 2 (ppr mbinds) + +nonStdGuardErr guards + = hang (ptext SLIT("accepting non-standard pattern guards (-fglasgow-exts to suppress this message)")) + 4 (interpp'SP guards) +\end{code} |