X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Frename%2FRnBinds.lhs;h=13035e72e2831185bc58ee74c632c381ac49b151;hb=876b4ef2093cb9c104db33c7db1200b941b6d079;hp=4f302044b81d1b764a01a875e98b63c9e849a48d;hpb=e0eaaf09894f74939166568573b36cb5bdafcfc7;p=ghc-hetmet.git diff --git a/ghc/compiler/rename/RnBinds.lhs b/ghc/compiler/rename/RnBinds.lhs index 4f30204..13035e7 100644 --- a/ghc/compiler/rename/RnBinds.lhs +++ b/ghc/compiler/rename/RnBinds.lhs @@ -1,5 +1,5 @@ % -% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996 +% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998 % \section[RnBinds]{Renaming and dependency analysis of bindings} @@ -10,38 +10,43 @@ they may be affected by renaming (which isn't fully worked out yet). \begin{code} module RnBinds ( - rnTopBinds, rnTopMonoBinds, - rnMethodBinds, renameSigs, - rnBinds, rnMonoBinds + rnTopBinds, + rnLocalBindsAndThen, rnValBindsAndThen, rnValBinds, trimWith, + rnMethodBinds, renameSigs, + rnMatchGroup, rnGRHSs ) where #include "HsVersions.h" -import {-# SOURCE #-} RnSource ( rnHsSigType ) +import {-# SOURCE #-} RnExpr( rnLExpr, rnStmts ) import HsSyn -import HsBinds ( sigsForMe ) import RdrHsSyn import RnHsSyn -import RnMonad -import RnExpr ( rnMatch, rnGRHSsAndBinds, rnPat, checkPrecMatch ) -import RnEnv ( bindLocatedLocalsRn, lookupBndrRn, lookupOccRn, lookupGlobalOccRn, - newLocalNames, isUnboundName, warnUnusedBinds +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 CmdLineOpts ( opt_SigsRequired ) -import Digraph ( stronglyConnComp, SCC(..) ) -import Name ( OccName(..), Provenance, - Name, isExportedName, - NameSet, emptyNameSet, mkNameSet, unionNameSets, - minusNameSet, unionManyNameSets, elemNameSet, unitNameSet, nameSetToList - ) -import BasicTypes ( RecFlag(..), TopLevelFlag(..) ) -import Util ( thenCmp, removeDups, panic, panic#, assertPanic ) -import UniqSet ( UniqSet ) -import ListSetOps ( minusList ) -import Bag ( bagToList ) -import UniqFM ( UniqFM ) +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 @@ -70,11 +75,6 @@ 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). -\begin{code} -type VertexTag = Int -type Cycle = [VertexTag] -type Edge = (VertexTag, VertexTag) -\end{code} %************************************************************************ %* * @@ -105,7 +105,7 @@ a set of variables free in @Exp@ is written @fvExp@ %************************************************************************ %* * -%* analysing polymorphic bindings (HsBinds, Bind, MonoBinds) * +%* analysing polymorphic bindings (HsBindGroup, HsBind) %* * %************************************************************************ @@ -117,7 +117,7 @@ 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 @FlatMonoBindsInfo@) containing: +(a @FlatMonoBinds@) containing: \begin{enumerate} \item @@ -151,381 +151,472 @@ it expects the global environment to contain bindings for the binders %************************************************************************ %* * -%* Top-level bindings +\subsubsection{ Top-level bindings} %* * %************************************************************************ -@rnTopBinds@ assumes that the environment already +@rnTopMonoBinds@ assumes that the environment already contains bindings for the binders of this particular binding. \begin{code} -rnTopBinds :: RdrNameHsBinds -> RnMS s RenamedHsBinds +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} -rnTopBinds EmptyBinds = returnRn EmptyBinds -rnTopBinds (MonoBind bind sigs _) = rnTopMonoBinds bind sigs - -- The parser doesn't produce other forms -rnTopMonoBinds EmptyMonoBinds sigs - = returnRn EmptyBinds +%********************************************************* +%* * + HsLocalBinds +%* * +%********************************************************* -rnTopMonoBinds mbinds sigs - = mapRn lookupBndrRn binder_rdr_names `thenRn` \ binder_names -> - let - binder_set = mkNameSet binder_names - exported_binders = mkNameSet (filter isExportedName binder_names) - in - rn_mono_binds TopLevel - binder_set mbinds sigs `thenRn` \ (new_binds, fv_set) -> - let - unused_binders = binder_set `minusNameSet` (fv_set `unionNameSets` exported_binders) - in - warnUnusedBinds unused_binders `thenRn_` - returnRn new_binds - where - binder_rdr_names = map fst (bagToList (collectMonoBinders mbinds)) +\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} + %************************************************************************ %* * -%* Nested binds + ValBinds %* * %************************************************************************ -@rnMonoBinds@ - - collects up the binders for this declaration group, - - checks that they form a set - - extends the environment to bind them to new local names - - calls @rnMonoBinds@ to do the real work - \begin{code} -rnBinds :: RdrNameHsBinds - -> (RenamedHsBinds -> RnMS s (result, FreeVars)) - -> RnMS s (result, FreeVars) +rnValBindsAndThen :: HsValBinds RdrName + -> (HsValBinds Name -> RnM (result, FreeVars)) + -> RnM (result, FreeVars) -rnBinds EmptyBinds thing_inside = thing_inside EmptyBinds -rnBinds (MonoBind bind sigs _) thing_inside = rnMonoBinds bind sigs thing_inside - -- the parser doesn't produce other forms +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 ] $ -rnMonoBinds :: RdrNameMonoBinds -> [RdrNameSig] - -> (RenamedHsBinds -> RnMS s (result, FreeVars)) - -> RnMS s (result, FreeVars) + -- Do the business + rnValBinds (trimWith bndrs) binds `thenM` \ (binds, bind_dus) -> -rnMonoBinds EmptyMonoBinds sigs thing_inside = thing_inside EmptyBinds + -- Now do the "thing inside" + thing_inside binds `thenM` \ (result,result_fvs) -> -rnMonoBinds mbinds sigs thing_inside -- Non-empty monobinds - = -- Extract all the binders in this group, - -- and extend current scope, inventing new names for the new binders - -- This also checks that the names form a set - bindLocatedLocalsRn (text "binding group") mbinders_w_srclocs $ \ new_mbinders -> + -- Final error checking let - binder_set = mkNameSet new_mbinders + 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 - rn_mono_binds NotTopLevel - binder_set mbinds sigs `thenRn` \ (binds,bind_fvs) -> + warnUnusedLocalBinds unused_bndrs `thenM_` - -- Now do the "thing inside", and deal with the free-variable calculations - thing_inside binds `thenRn` \ (result,result_fvs) -> - let - all_fvs = result_fvs `unionNameSets` bind_fvs - net_fvs = all_fvs `minusNameSet` binder_set - unused_binders = binder_set `minusNameSet` all_fvs - in - warnUnusedBinds unused_binders `thenRn_` - returnRn (result, net_fvs) + returnM (result, delListFromNameSet all_uses bndrs) where - mbinders_w_srclocs = bagToList (collectMonoBinders mbinds) -\end{code} - + mbinders_w_srclocs = collectHsBindLocatedBinders mbinds + doc = text "In the binding group for:" + <+> pprWithCommas ppr (map unLoc mbinders_w_srclocs) -%************************************************************************ -%* * -%* MonoBinds -- the main work is done here -%* * -%************************************************************************ +--------------------- +rnValBinds :: (FreeVars -> FreeVars) + -> HsValBinds RdrName + -> RnM (HsValBinds Name, DefUses) +-- Assumes the binders of the binding are in scope already -@rnMonoBinds@ is used by *both* top-level and nested bindings. It -assumes that all variables bound in this group are already in scope. -This is done *either* by pass 3 (for the top-level bindings), *or* by -@rnNestedMonoBinds@ (for the nested ones). +rnValBinds trim (ValBindsIn mbinds sigs) + = do { sigs' <- rename_sigs sigs -\begin{code} -rn_mono_binds :: TopLevelFlag - -> NameSet -- Binders of this group - -> RdrNameMonoBinds - -> [RdrNameSig] -- Signatures attached to this group - -> RnMS s (RenamedHsBinds, -- - FreeVars) -- Free variables - -rn_mono_binds top_lev binders mbinds sigs - = - -- Rename the bindings, returning a MonoBindsInfo - -- which is a list of indivisible vertices so far as - -- the strongly-connected-components (SCC) analysis is concerned - renameSigs top_lev False binders sigs `thenRn` \ siglist -> - flattenMonoBinds siglist mbinds `thenRn` \ mbinds_info -> - - -- Do the SCC analysis - let edges = mkEdges (mbinds_info `zip` [(0::Int)..]) - scc_result = stronglyConnComp edges - final_binds = foldr1 ThenBinds (map reconstructCycle scc_result) - - -- Deal with bound and free-var calculation - rhs_fvs = unionManyNameSets [fvs | (_,fvs,_,_) <- mbinds_info] - in - returnRn (final_binds, rhs_fvs) -\end{code} + ; binds_w_dus <- mapBagM (rnBind (mkSigTvFn sigs') trim) mbinds -@flattenMonoBinds@ is ever-so-slightly magical in that it sticks -unique ``vertex tags'' on its output; minor plumbing required. - -\begin{code} -flattenMonoBinds :: [RenamedSig] -- Signatures - -> RdrNameMonoBinds - -> RnMS s [FlatMonoBindsInfo] + ; let (binds', bind_dus) = depAnalBinds binds_w_dus -flattenMonoBinds sigs EmptyMonoBinds = returnRn [] + -- 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' -flattenMonoBinds sigs (AndMonoBinds bs1 bs2) - = flattenMonoBinds sigs bs1 `thenRn` \ flat1 -> - flattenMonoBinds sigs bs2 `thenRn` \ flat2 -> - returnRn (flat1 ++ flat2) + ; return (ValBindsOut binds' sigs', + usesOnly (hsSigsFVs sigs') `plusDU` bind_dus) } -flattenMonoBinds sigs (PatMonoBind pat grhss_and_binds locn) - = pushSrcLocRn locn $ - rnPat pat `thenRn` \ pat' -> - rnGRHSsAndBinds grhss_and_binds `thenRn` \ (grhss_and_binds', fvs) -> - -- Find which things are bound in this group - let - names_bound_here = mkNameSet (collectPatBinders pat') - sigs_for_me = sigsForMe (`elemNameSet` names_bound_here) sigs - sigs_fvs = foldr sig_fv emptyNameSet sigs_for_me - in - returnRn - [(names_bound_here, - fvs `unionNameSets` sigs_fvs, - PatMonoBind pat' grhss_and_binds' locn, - sigs_for_me - )] - -flattenMonoBinds sigs (FunMonoBind name inf matches locn) - = pushSrcLocRn locn $ - mapRn (checkPrecMatch inf name) matches `thenRn_` - lookupBndrRn name `thenRn` \ name' -> - mapAndUnzipRn rnMatch matches `thenRn` \ (new_matches, fv_lists) -> - let - fvs = unionManyNameSets fv_lists - sigs_for_me = sigsForMe (name' ==) sigs - sigs_fvs = foldr sig_fv emptyNameSet sigs_for_me - in - returnRn - [(unitNameSet name', - fvs `unionNameSets` sigs_fvs, - FunMonoBind name' inf new_matches locn, - sigs_for_me - )] +--------------------- +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 an instance -declaration. like @rnMonoBinds@ but without dependency analysis. - -\begin{code} -rnMethodBinds :: RdrNameMonoBinds -> RnMS s RenamedMonoBinds - -rnMethodBinds EmptyMonoBinds = returnRn EmptyMonoBinds - -rnMethodBinds (AndMonoBinds mb1 mb2) - = andRn AndMonoBinds (rnMethodBinds mb1) - (rnMethodBinds mb2) +@rnMethodBinds@ is used for the method bindings of a class and an instance +declaration. Like @rnBinds@ but without dependency analysis. -rnMethodBinds (FunMonoBind name inf matches locn) - = pushSrcLocRn locn $ - mapRn (checkPrecMatch inf name) matches `thenRn_` +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. - lookupGlobalOccRn name `thenRn` \ sel_name -> +\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 - mapAndUnzipRn rnMatch matches `thenRn` \ (new_matches, _) -> - returnRn (FunMonoBind sel_name inf new_matches locn) + 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 -rnMethodBinds (PatMonoBind (VarPatIn name) grhss_and_binds locn) - = pushSrcLocRn locn $ - lookupGlobalOccRn name `thenRn` \ sel_name -> - rnGRHSsAndBinds grhss_and_binds `thenRn` \ (grhss_and_binds', _) -> - returnRn (PatMonoBind (VarPatIn sel_name) grhss_and_binds' locn) -- Can't handle method pattern-bindings which bind multiple methods. -rnMethodBinds mbind@(PatMonoBind other_pat _ locn) - = pushSrcLocRn locn $ - failWithRn EmptyMonoBinds (methodBindErr mbind) +rnMethodBind cls gen_tyvars mbind@(L loc (PatBind other_pat _ _ _)) + = addLocErr mbind methodBindErr `thenM_` + returnM (emptyBag, emptyFVs) \end{code} -\begin{code} --- If a SPECIALIZE pragma is of the "... = blah" form, --- then we'd better make sure "blah" is taken into --- acct in the dependency analysis (or we get an --- unexpected out-of-scope error)! WDP 95/07 - -sig_fv (SpecSig _ _ (Just blah) _) acc = acc `unionNameSets` (unitNameSet blah) -sig_fv _ acc = acc -\end{code} %************************************************************************ %* * -\subsection[reconstruct-deps]{Reconstructing dependencies} +\subsubsection[dep-Sigs]{Signatures (and user-pragmas for values)} %* * %************************************************************************ -This @MonoBinds@- and @ClassDecls@-specific code is segregated here, -as the two cases are similar. +@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} -reconstructCycle :: SCC FlatMonoBindsInfo - -> RenamedHsBinds - -reconstructCycle (AcyclicSCC (_, _, binds, sigs)) - = MonoBind binds sigs NonRecursive - -reconstructCycle (CyclicSCC cycle) - = MonoBind this_gp_binds this_gp_sigs Recursive +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 - this_gp_binds = foldr1 AndMonoBinds [binds | (_, _, binds, _) <- cycle] - this_gp_sigs = foldr1 (++) [sigs | (_, _, _, sigs) <- cycle] + -- 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} -%************************************************************************ -%* * -%* Manipulating FlatMonoBindInfo * -%* * -%************************************************************************ -During analysis a @MonoBinds@ is flattened to a @FlatMonoBindsInfo@. -The @RenamedMonoBinds@ is always an empty bind, a pattern binding or -a function binding, and has itself been dependency-analysed and -renamed. +************************************************************************ +* * +\subsection{Match} +* * +************************************************************************ \begin{code} -type FlatMonoBindsInfo - = (NameSet, -- Set of names defined in this vertex - NameSet, -- Set of names used in this vertex - RenamedMonoBinds, - [RenamedSig]) -- Signatures, if any, for this vertex - -mkEdges :: [(FlatMonoBindsInfo, VertexTag)] -> [(FlatMonoBindsInfo, VertexTag, [VertexTag])] - -mkEdges flat_info - = [ (info, tag, dest_vertices (nameSetToList names_used)) - | (info@(names_defined, names_used, mbind, sigs), tag) <- flat_info - ] +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 - -- An edge (v,v') indicates that v depends on v' - dest_vertices src_mentions = [ target_vertex - | ((names_defined, _, _, _), target_vertex) <- flat_info, - mentioned_name <- src_mentions, - mentioned_name `elemNameSet` names_defined - ] + rhs_sig_tys = case maybe_rhs_sig of + Nothing -> [] + Just ty -> [ty] + doc_sig = text "In a result type-signature" \end{code} %************************************************************************ %* * -\subsubsection[dep-Sigs]{Signatures (and user-pragmas for values)} +\subsubsection{Guarded right-hand sides (GRHSs)} %* * %************************************************************************ -@renameSigs@ checks for: (a)~more than one sig for one thing; -(b)~signatures given for things not bound here; (c)~with suitably -flaggery, that all top-level things have type signatures. - \begin{code} -renameSigs :: TopLevelFlag - -> Bool -- True <-> sigs for an instance decl - -- hence SPECIALISE instance prags ok - -> NameSet -- Set of names bound in this group - -> [RdrNameSig] - -> RnMS s [RenamedSig] -- List of Sig constructors +rnGRHSs :: HsMatchContext Name -> GRHSs RdrName -> RnM (GRHSs Name, FreeVars) -renameSigs top_lev inst_decl binders sigs - = -- Rename the signatures - mapRn renameSig sigs `thenRn` \ sigs' -> +rnGRHSs ctxt (GRHSs grhss binds) + = rnLocalBindsAndThen binds $ \ binds' -> + mapFvRn (rnGRHS ctxt) grhss `thenM` \ (grhss', fvGRHSs) -> + returnM (GRHSs grhss' binds', fvGRHSs) - -- Check for (a) duplicate signatures - -- (b) signatures for things not in this group - -- (c) optionally, bindings with no signature - let - (goodies, dups) = removeDups cmp_sig (sigsForMe (not . isUnboundName) sigs') - not_this_group = sigsForMe (not . (`elemNameSet` binders)) goodies - spec_inst_sigs = [s | s@(SpecInstSig _ _) <- goodies] - type_sig_vars = [n | Sig n _ _ <- goodies] - sigs_required = case top_lev of {TopLevel -> opt_SigsRequired; NotTopLevel -> False} - un_sigd_binders | sigs_required = nameSetToList binders `minusList` type_sig_vars - | otherwise = [] - in - mapRn dupSigDeclErr dups `thenRn_` - mapRn unknownSigErr not_this_group `thenRn_` - (if not inst_decl then - mapRn unknownSigErr spec_inst_sigs - else - returnRn [] - ) `thenRn_` - mapRn (addErrRn.missingSigErr) un_sigd_binders `thenRn_` - - returnRn sigs' -- bad ones and all: - -- we need bindings of *some* sort for every name - - -renameSig (Sig v ty src_loc) - = pushSrcLocRn src_loc $ - lookupBndrRn v `thenRn` \ new_v -> - rnHsSigType (quotes (ppr v)) ty `thenRn` \ new_ty -> - returnRn (Sig new_v new_ty src_loc) - -renameSig (SpecInstSig ty src_loc) - = pushSrcLocRn src_loc $ - rnHsSigType (text "A SPECIALISE instance pragma") ty `thenRn` \ new_ty -> - returnRn (SpecInstSig new_ty src_loc) - -renameSig (SpecSig v ty using src_loc) - = pushSrcLocRn src_loc $ - lookupBndrRn v `thenRn` \ new_v -> - rnHsSigType (quotes (ppr v)) ty `thenRn` \ new_ty -> - rn_using using `thenRn` \ new_using -> - returnRn (SpecSig new_v new_ty new_using src_loc) - where - rn_using Nothing = returnRn Nothing - rn_using (Just x) = lookupOccRn x `thenRn` \ new_x -> - returnRn (Just new_x) - -renameSig (InlineSig v src_loc) - = pushSrcLocRn src_loc $ - lookupBndrRn v `thenRn` \ new_v -> - returnRn (InlineSig new_v src_loc) -\end{code} +rnGRHS :: HsMatchContext Name -> LGRHS RdrName -> RnM (LGRHS Name, FreeVars) +rnGRHS ctxt = wrapLocFstM (rnGRHS' ctxt) -Checking for distinct signatures; oh, so boring +rnGRHS' ctxt (GRHS guards rhs) + = do { opt_GlasgowExts <- doptM Opt_GlasgowExts + ; ((guards', rhs'), fvs) <- rnStmts (PatGuard ctxt) guards $ + rnLExpr rhs -\begin{code} -cmp_sig :: RenamedSig -> RenamedSig -> Ordering -cmp_sig (Sig n1 _ _) (Sig n2 _ _) = n1 `compare` n2 -cmp_sig (InlineSig n1 _) (InlineSig n2 _) = n1 `compare` n2 -cmp_sig (SpecInstSig ty1 _) (SpecInstSig ty2 _) = cmpHsType compare ty1 ty2 -cmp_sig (SpecSig n1 ty1 _ _) (SpecSig n2 ty2 _ _) - = -- may have many specialisations for one value; - -- but not ones that are exactly the same... - thenCmp (n1 `compare` n2) (cmpHsType compare ty1 ty2) - -cmp_sig other_1 other_2 -- Tags *must* be different - | (sig_tag other_1) _LT_ (sig_tag other_2) = LT - | otherwise = GT - -sig_tag (Sig n1 _ _) = (ILIT(1) :: FAST_INT) -sig_tag (SpecSig n1 _ _ _) = ILIT(2) -sig_tag (InlineSig n1 _) = ILIT(3) -sig_tag (SpecInstSig _ _) = ILIT(5) -sig_tag _ = panic# "tag(RnBinds)" + ; 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} %************************************************************************ @@ -535,32 +626,35 @@ sig_tag _ = panic# "tag(RnBinds)" %************************************************************************ \begin{code} -dupSigDeclErr (sig:sigs) - = pushSrcLocRn loc $ - addErrRn (sep [ptext SLIT("Duplicate"), - ptext what_it_is <> colon, - ppr sig]) +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, loc) = sig_doc sig + what_it_is = hsSigDoc sig + ppr_sig (L loc sig) = ppr loc <> colon <+> ppr sig -unknownSigErr sig - = pushSrcLocRn loc $ - addErrRn (sep [ptext SLIT("Misplaced"), - ptext what_it_is <> colon, - ppr sig]) +unknownSigErr (L loc sig) + = addErrAt loc $ + sep [ptext SLIT("Misplaced") <+> what_it_is <> colon, ppr sig] where - (what_it_is, loc) = sig_doc sig - -sig_doc (Sig _ _ loc) = (SLIT("type signature"),loc) -sig_doc (ClassOpSig _ _ _ loc) = (SLIT("class-method type signature"), loc) -sig_doc (SpecSig _ _ _ loc) = (SLIT("SPECIALISE pragma"),loc) -sig_doc (InlineSig _ loc) = (SLIT("INLINE pragma"),loc) -sig_doc (SpecInstSig _ loc) = (SLIT("SPECIALISE instance pragma"),loc) + what_it_is = hsSigDoc sig -missingSigErr var - = sep [ptext SLIT("Definition but no type signature for"), quotes (ppr var)] +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("Can't handle multiple methods defined by one pattern binding")) - 4 (ppr 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}