-\%
+%
% (c) The GRASP/AQUA Project, Glasgow University, 1992-2006
%
\section[RnEnv]{Environment manipulation for the renamer monad}
newTopSrcBinder, lookupFamInstDeclBndr,
lookupLocatedTopBndrRn, lookupTopBndrRn,
lookupLocatedOccRn, lookupOccRn,
- lookupLocatedGlobalOccRn, lookupGlobalOccRn,
- lookupLocalDataTcNames, lookupSrcOcc_maybe,
- lookupSigOccRn,
+ lookupLocatedGlobalOccRn,
+ lookupGlobalOccRn, lookupGlobalOccRn_maybe,
+ lookupLocalDataTcNames, lookupSigOccRn,
lookupFixityRn, lookupTyFixityRn,
lookupInstDeclBndr, lookupRecordBndr, lookupConstructorFields,
- lookupSyntaxName, lookupSyntaxTable, lookupImportedName,
+ lookupSyntaxName, lookupSyntaxTable,
lookupGreRn, lookupGreLocalRn, lookupGreRn_maybe,
- getLookupOccRn,
+ getLookupOccRn, addUsedRdrNames,
newLocalsRn, newIPNameRn,
bindLocalNames, bindLocalNamesFV,
mapFvRn, mapFvRnCPS,
warnUnusedMatches, warnUnusedModules, warnUnusedImports,
warnUnusedTopBinds, warnUnusedLocalBinds,
- dataTcOccs, unknownNameErr, perhapsForallMsg
+ dataTcOccs, unknownNameErr, kindSigErr, perhapsForallMsg,
+
+ checkM
) where
#include "HsVersions.h"
import RdrHsSyn ( extractHsTyRdrTyVars )
import RdrName
import HscTypes ( availNames, ModIface(..), FixItem(..), lookupFixity)
-import TcEnv ( tcLookupDataCon, isBrackStage )
+import TcEnv ( tcLookupDataCon, tcLookupField, isBrackStage )
import TcRnMonad
+import Id ( isRecordSelector )
import Name ( Name, nameIsLocalOrFrom, mkInternalName, isWiredInName,
nameSrcLoc, nameSrcSpan, nameOccName, nameModule, isExternalName )
import NameSet
import DynFlags
import FastString
import Control.Monad
+import qualified Data.Set as Set
\end{code}
\begin{code}
Looking up a name in the RnEnv.
+Note [Type and class operator definitions]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+We want to reject all of these unless we have -XTypeOperators (Trac #3265)
+ data a :*: b = ...
+ class a :*: b where ...
+ data (:*:) a b = ....
+ class (:*:) a b where ...
+The latter two mean that we are not just looking for a
+*syntactically-infix* declaration, but one that uses an operator
+OccName. We use OccName.isSymOcc to detect that case, which isn't
+terribly efficient, but there seems to be no better way.
+
\begin{code}
lookupTopBndrRn :: RdrName -> RnM Name
lookupTopBndrRn n = do nopt <- lookupTopBndrRn_maybe n
; return (Just n)}
| otherwise
- = do { mb_gre <- lookupGreLocalRn rdr_name
+ = do { -- Check for operators in type or class declarations
+ -- See Note [Type and class operator definitions]
+ let occ = rdrNameOcc rdr_name
+ ; when (isTcOcc occ && isSymOcc occ)
+ (do { op_ok <- doptM Opt_TypeOperators
+ ; checkM op_ok (addErr (opDeclErr rdr_name)) })
+
+ ; mb_gre <- lookupGreLocalRn rdr_name
; case mb_gre of
Nothing -> returnM Nothing
Just gre -> returnM (Just $ gre_name gre) }
-----------------------------------------------
lookupRecordBndr :: Maybe (Located Name) -> Located RdrName -> RnM (Located Name)
-- Used for record construction and pattern matching
--- When the -fdisambiguate-record-fields flag is on, take account of the
+-- When the -XDisambiguateRecordFields flag is on, take account of the
-- constructor name to disambiguate which field to use; it's just the
-- same as for instance decls
+--
+-- NB: Consider this:
+-- module Foo where { data R = R { fld :: Int } }
+-- module Odd where { import Foo; fld x = x { fld = 3 } }
+-- Arguably this should work, because the reference to 'fld' is
+-- unambiguous because there is only one field id 'fld' in scope.
+-- But currently it's rejected.
lookupRecordBndr Nothing rdr_name
= lookupLocatedGlobalOccRn rdr_name
lookupRecordBndr (Just (L _ data_con)) rdr_name
lookupConstructorFields con_name
= do { this_mod <- getModule
; if nameIsLocalOrFrom this_mod con_name then
- do { field_env <- getRecFieldEnv
+ do { RecFields field_env _ <- getRecFieldEnv
; return (lookupNameEnv field_env con_name `orElse` []) }
else
do { con <- tcLookupDataCon con_name
lookup_sub_bndr is_good doc rdr_name
| isUnqual rdr_name -- Find all the things the rdr-name maps to
= do { -- and pick the one with the right parent name
+ ; addUsedRdrName rdr_name
; env <- getGlobalRdrEnv
; case filter is_good (lookupGlobalRdrEnv env (rdrNameOcc rdr_name)) of
-- NB: lookupGlobalRdrEnv, not lookupGRE_RdrName!
}
| otherwise -- Occurs in derived instances, where we just
- -- refer directly to the right method
- = ASSERT2( not (isQual rdr_name), ppr rdr_name )
- -- NB: qualified names are rejected by the parser
- lookupImportedName rdr_name
+ -- refer directly to the right method with an Orig
+ -- And record fields can be Quals: C { F.f = x }
+ = lookupGlobalOccRn rdr_name
newIPNameRn :: IPName RdrName -> TcRnIf m n (IPName Name)
newIPNameRn ip_rdr = newIPName (mapIPName rdrNameOcc ip_rdr)
--- Looking up family names in type instances is a subtle affair. The family
--- may be imported, in which case we need to lookup the occurence of a global
--- name. Alternatively, the family may be in the same binding group (and in
--- fact in a declaration processed later), and we need to create a new top
--- source binder.
---
--- So, also this is strictly speaking an occurence, we cannot raise an error
--- message yet for instances without a family declaration. This will happen
--- during renaming the type instance declaration in RnSource.rnTyClDecl.
+-- If the family is declared locally, it will not yet be in the main
+-- environment; hence, we pass in an extra one here, which we check first.
+-- See "Note [Looking up family names in family instances]" in 'RnNames'.
--
-lookupFamInstDeclBndr :: Module -> Located RdrName -> RnM Name
-lookupFamInstDeclBndr mod lrdr_name@(L _ rdr_name)
- = do { mb_gre <- lookupGreRn_maybe rdr_name
- ; case mb_gre of
- Just gre -> returnM (gre_name gre)
- Nothing -> newTopSrcBinder mod lrdr_name }
+lookupFamInstDeclBndr :: GlobalRdrEnv -> Located RdrName -> RnM Name
+lookupFamInstDeclBndr tyclGroupEnv (L loc rdr_name)
+ = setSrcSpan loc $
+ case lookupGRE_RdrName rdr_name tyclGroupEnv of
+ (gre:_) -> return $ gre_name gre
+ -- if there is more than one, an error will be raised elsewhere
+ [] -> lookupOccRn rdr_name
+
--------------------------------------------------
-- Occurrences
lookupGlobalOccRn :: RdrName -> RnM Name
-- lookupGlobalOccRn is like lookupOccRn, except that it looks in the global
--- environment. It's used only for
--- record field names
--- class op names in class and instance decls
+-- environment. Adds an error message if the RdrName is not in scope.
+-- Also has a special case for GHCi.
lookupGlobalOccRn rdr_name
- | not (isSrcRdrName rdr_name)
- = lookupImportedName rdr_name
-
- | otherwise
- = do
- -- First look up the name in the normal environment.
- mb_gre <- lookupGreRn_maybe rdr_name
- case mb_gre of {
- Just gre -> returnM (gre_name gre) ;
- Nothing -> do
-
- -- We allow qualified names on the command line to refer to
- -- *any* name exported by any module in scope, just as if
- -- there was an "import qualified M" declaration for every
- -- module.
- allow_qual <- doptM Opt_ImplicitImportQualified
- mod <- getModule
+ = do { -- First look up the name in the normal environment.
+ mb_name <- lookupGlobalOccRn_maybe rdr_name
+ ; case mb_name of {
+ Just n -> return n ;
+ Nothing -> do
+
+ { -- We allow qualified names on the command line to refer to
+ -- *any* name exported by any module in scope, just as if there
+ -- was an "import qualified M" declaration for every module.
+ allow_qual <- doptM Opt_ImplicitImportQualified
+ ; mod <- getModule
-- This test is not expensive,
-- and only happens for failed lookups
- if isQual rdr_name && allow_qual && mod == iNTERACTIVE
- then lookupQualifiedName rdr_name
- else unboundName rdr_name
- }
-
-lookupImportedName :: RdrName -> TcRnIf m n Name
--- Lookup the occurrence of an imported name
--- The RdrName is *always* qualified or Exact
--- Treat it as an original name, and conjure up the Name
--- Usually it's Exact or Orig, but it can be Qual if it
--- comes from an hi-boot file. (This minor infelicity is
--- just to reduce duplication in the parser.)
-lookupImportedName rdr_name
- | Just n <- isExact_maybe rdr_name
- -- This happens in derived code
- = returnM n
-
- -- Always Orig, even when reading a .hi-boot file
+ ; if isQual rdr_name && allow_qual && mod == iNTERACTIVE
+ then lookupQualifiedName rdr_name
+ else unboundName rdr_name } } }
+
+lookupGlobalOccRn_maybe :: RdrName -> RnM (Maybe Name)
+-- No filter function; does not report an error on failure
+
+lookupGlobalOccRn_maybe rdr_name
+ | Just n <- isExact_maybe rdr_name -- This happens in derived code
+ = return (Just n)
+
| Just (rdr_mod, rdr_occ) <- isOrig_maybe rdr_name
- = lookupOrig rdr_mod rdr_occ
+ = do { n <- lookupOrig rdr_mod rdr_occ; return (Just n) }
| otherwise
- = pprPanic "RnEnv.lookupImportedName" (ppr rdr_name)
+ = do { mb_gre <- lookupGreRn_maybe rdr_name
+ ; case mb_gre of
+ Nothing -> return Nothing
+ Just gre -> return (Just (gre_name gre)) }
+
unboundName :: RdrName -> RnM Name
unboundName rdr_name
-- Lookup in the Global RdrEnv of the module
--------------------------------------------------
-lookupSrcOcc_maybe :: RdrName -> RnM (Maybe Name)
--- No filter function; does not report an error on failure
-lookupSrcOcc_maybe rdr_name
- = do { mb_gre <- lookupGreRn_maybe rdr_name
- ; case mb_gre of
- Nothing -> returnM Nothing
- Just gre -> returnM (Just (gre_name gre)) }
-
--------------------------
lookupGreRn_maybe :: RdrName -> RnM (Maybe GlobalRdrElt)
-- Just look up the RdrName in the GlobalRdrEnv
lookupGreRn_maybe rdr_name
- = lookupGreRn_help rdr_name (lookupGRE_RdrName rdr_name)
+ = do { mGre <- lookupGreRn_help rdr_name (lookupGRE_RdrName rdr_name)
+ ; case mGre of
+ Just gre ->
+ case gre_prov gre of
+ LocalDef -> return ()
+ Imported _ -> addUsedRdrName rdr_name
+ Nothing ->
+ return ()
+ ; return mGre }
+
+addUsedRdrName :: RdrName -> RnM ()
+addUsedRdrName rdr
+ = do { env <- getGblEnv
+ ; updMutVar (tcg_used_rdrnames env)
+ (\s -> Set.insert rdr s) }
+
+addUsedRdrNames :: [RdrName] -> RnM ()
+addUsedRdrNames rdrs
+ = do { env <- getGblEnv
+ ; updMutVar (tcg_used_rdrnames env)
+ (\s -> foldr Set.insert s rdrs) }
lookupGreRn :: RdrName -> RnM GlobalRdrElt
-- If not found, add error message, and return a fake GRE
-> RnM a
-- Haskell-98 binding of type variables; e.g. within a data type decl
bindTyVarsRn doc_str tyvar_names enclosed_scope
- = let
- located_tyvars = hsLTyVarLocNames tyvar_names
- in
- bindLocatedLocalsRn doc_str located_tyvars $ \ names ->
- enclosed_scope (zipWith replace tyvar_names names)
- where
- replace (L loc n1) n2 = L loc (replaceTyVarName n1 n2)
+ = bindLocatedLocalsRn doc_str located_tyvars $ \ names ->
+ do { kind_sigs_ok <- doptM Opt_KindSignatures
+ ; checkM (null kinded_tyvars || kind_sigs_ok)
+ (mapM_ (addErr . kindSigErr) kinded_tyvars)
+ ; enclosed_scope (zipWith replace tyvar_names names) }
+ where
+ replace (L loc n1) n2 = L loc (replaceTyVarName n1 n2)
+ located_tyvars = hsLTyVarLocNames tyvar_names
+ kinded_tyvars = [n | L _ (KindedTyVar n _) <- tyvar_names]
bindPatSigTyVars :: [LHsType RdrName] -> ([Name] -> RnM a) -> RnM a
-- Find the type variables in the pattern type
; mappM_ check_shadow loc_rdr_names }
where
check_shadow (loc, occ)
+ | startsWithUnderscore occ = return () -- Do not report shadowing for "_x"
+ -- See Trac #3262
| Just n <- mb_local = complain [ptext (sLit "bound at") <+> ppr (nameSrcLoc n)]
- | not (null gres) = complain (map pprNameProvenance gres)
- | otherwise = return ()
+ | otherwise = do { gres' <- filterM is_shadowed_gre gres
+ ; complain (map pprNameProvenance gres') }
where
+ complain [] = return ()
complain pp_locs = addWarnAt loc (shadowedNameWarn doc_str occ pp_locs)
mb_local = lookupLocalRdrOcc local_env occ
gres = lookupGRE_RdrName (mkRdrUnqual occ) global_env
-- Make an Unqualified RdrName and look that up, so that
-- we don't find any GREs that are in scope qualified-only
+
+ is_shadowed_gre :: GlobalRdrElt -> RnM Bool
+ -- Returns False for record selectors that are shadowed, when
+ -- punning or wild-cards are on (cf Trac #2723)
+ is_shadowed_gre gre@(GRE { gre_par = ParentIs _ })
+ = do { dflags <- getDOpts
+ ; if (dopt Opt_RecordPuns dflags || dopt Opt_RecordWildCards dflags)
+ then do { is_fld <- is_rec_fld gre; return (not is_fld) }
+ else return True }
+ is_shadowed_gre _other = return True
+
+ is_rec_fld gre -- Return True for record selector ids
+ | isLocalGRE gre = do { RecFields _ fld_set <- getRecFieldEnv
+ ; return (gre_name gre `elemNameSet` fld_set) }
+ | otherwise = do { sel_id <- tcLookupField (gre_name gre)
+ ; return (isRecordSelector sel_id) }
\end{code}
| isWiredInName name = False -- Don't report unused wired-in names
-- Otherwise we get a zillion warnings
-- from Data.Tuple
- | otherwise = reportIfUnused (nameOccName name)
+ | otherwise = not (startsWithUnderscore (nameOccName name))
-------------------------
warnUnusedName :: (Name, Provenance) -> RnM ()
warnUnusedName (name, LocalDef)
- = addUnusedWarning name (srcLocSpan (nameSrcLoc name))
+ = addUnusedWarning name (nameSrcSpan name)
(ptext (sLit "Defined but not used"))
warnUnusedName (name, Imported is)
| otherwise = ptext (sLit "Bound at:") <+>
vcat (map ppr (sortLe (<=) locs))
+kindSigErr :: Outputable a => a -> SDoc
+kindSigErr thing
+ = hang (ptext (sLit "Illegal kind signature for") <+> quotes (ppr thing))
+ 2 (ptext (sLit "Perhaps you intended to use -XKindSignatures"))
+
+
badQualBndrErr :: RdrName -> SDoc
badQualBndrErr rdr_name
= ptext (sLit "Qualified name in binding position:") <+> ppr rdr_name
+
+opDeclErr :: RdrName -> SDoc
+opDeclErr n
+ = hang (ptext (sLit "Illegal declaration of a type or class operator") <+> quotes (ppr n))
+ 2 (ptext (sLit "Use -XTypeOperators to declare operators in type and declarations"))
\end{code}
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