--
-- INVARIANT: All the members of the list have distinct
-- 'gre_name' fields; that is, no duplicate Names
+--
+-- INVARIANT: Imported provenance => Name is an ExternalName
+-- However LocalDefs can have an InternalName. This
+-- happens only when type-checking a [d| ... |] Template
+-- Haskell quotation; see this note in RnNames
+-- Note [Top-level Names in Template Haskell decl quotes]
-- | An element of the 'GlobalRdrEnv'
data GlobalRdrElt
pick :: GlobalRdrElt -> Maybe GlobalRdrElt
pick gre@(GRE {gre_prov = LocalDef, gre_name = n}) -- Local def
- | rdr_is_unqual = Just gre
- | Just (mod,_) <- rdr_is_qual,
- mod == moduleName (nameModule n) = Just gre
- | otherwise = Nothing
+ | rdr_is_unqual = Just gre
+ | Just (mod,_) <- rdr_is_qual -- Qualified name
+ , Just n_mod <- nameModule_maybe n -- Binder is External
+ , mod == moduleName n_mod = Just gre
+ | otherwise = Nothing
pick gre@(GRE {gre_prov = Imported [is]}) -- Single import (efficiency)
| rdr_is_unqual,
- not (is_qual (is_decl is)) = Just gre
+ not (is_qual (is_decl is)) = Just gre
| Just (mod,_) <- rdr_is_qual,
- mod == is_as (is_decl is) = Just gre
- | otherwise = Nothing
+ mod == is_as (is_decl is) = Just gre
+ | otherwise = Nothing
pick gre@(GRE {gre_prov = Imported is}) -- Multiple import
| null filtered_is = Nothing
| otherwise = Just (gre {gre_prov = Imported filtered_is})
-- For source type/class decls, this is the first occurrence
-- For iface ones, the LoadIface has alrady allocated a suitable name in the cache
newImplicitBinder base_name mk_sys_occ
- = newGlobalBinder (nameModule base_name)
- (mk_sys_occ (nameOccName base_name))
- (nameSrcSpan base_name)
+ | Just mod <- nameModule_maybe base_name
+ = newGlobalBinder mod occ loc
+ | otherwise -- When typechecking a [d| decl bracket |],
+ -- TH generates types, classes etc with Internal names,
+ -- so we follow suit for the implicit binders
+ = do { uniq <- newUnique
+ ; return (mkInternalName uniq occ loc) }
+ where
+ occ = mk_sys_occ (nameOccName base_name)
+ loc = nameSrcSpan base_name
ifaceExportNames :: [IfaceExport] -> TcRnIf gbl lcl [AvailInfo]
ifaceExportNames exports = do
-- use himself. The z-encoding for ':' is "ZC", so the z-encoded
-- module name still starts with a capital letter, which keeps
-- the z-encoded version consistent.
-iNTERACTIVE, thFAKE :: Module
+iNTERACTIVE :: Module
iNTERACTIVE = mkMainModule (fsLit ":Interactive")
-thFAKE = mkMainModule (fsLit ":THFake")
pRELUDE_NAME, mAIN_NAME :: ModuleName
pRELUDE_NAME = mkModuleNameFS (fsLit "Prelude")
rnValBindsRHSGen trim bound_names (ValBindsIn mbinds sigs) = do
-- rename the sigs
env <- getGblEnv
- traceRn (ptext (sLit "Rename sigs") <+> ppr (tcg_rdr_env env))
sigs' <- renameSigs (Just (mkNameSet bound_names)) okBindSig sigs
-- rename the RHSes
binds_w_dus <- mapBagM (rnBind (mkSigTvFn sigs') trim) mbinds
import RdrHsSyn ( extractHsTyRdrTyVars )
import RdrName
import HscTypes ( availNames, ModIface(..), FixItem(..), lookupFixity)
-import TcEnv ( tcLookupDataCon )
+import TcEnv ( tcLookupDataCon, isBrackStage )
import TcRnMonad
import Name ( Name, nameIsLocalOrFrom, mkInternalName, isWiredInName,
nameSrcLoc, nameSrcSpan, nameOccName, nameModule, isExternalName )
(addErrAt loc (badQualBndrErr rdr_name))
-- Binders should not be qualified; if they are, and with a different
-- module name, we we get a confusing "M.T is not in scope" error later
- ; newGlobalBinder this_mod (rdrNameOcc rdr_name) loc }
+
+ ; stage <- getStage
+ ; if isBrackStage stage then
+ -- We are inside a TH bracket, so make an *Internal* name
+ -- See Note [Top-level Names in Template Haskell decl quotes] in RnNames
+ do { uniq <- newUnique
+ ; return (mkInternalName uniq (rdrNameOcc rdr_name) loc) }
+ else
+ -- Normal case
+ newGlobalBinder this_mod (rdrNameOcc rdr_name) loc }
\end{code}
%*********************************************************
rnMatchGroup, makeMiniFixityEnv)
import HsSyn
import TcRnMonad
+import TcEnv ( thRnBrack )
import RnEnv
import RnTypes ( rnHsTypeFVs,
mkOpFormRn, mkOpAppRn, mkNegAppRn, checkSectionPrec)
import RnPat
import DynFlags ( DynFlag(..) )
import BasicTypes ( FixityDirection(..) )
-import PrelNames ( thFAKE, hasKey, assertIdKey, assertErrorName,
+import PrelNames ( hasKey, assertIdKey, assertErrorName,
loopAName, choiceAName, appAName, arrAName, composeAName, firstAName,
negateName, thenMName, bindMName, failMName, groupWithName )
rnBracket (DecBr group)
= do { gbl_env <- getGblEnv
- ; let new_gbl_env = gbl_env { -- Set the module to thFAKE. The top-level names from the bracketed
- -- declarations will go into the name cache, and we don't want them to
- -- confuse the Names for the current module.
- -- By using a pretend module, thFAKE, we keep them safely out of the way.
- tcg_mod = thFAKE,
-
- -- The emptyDUs is so that we just collect uses for this group alone
- -- in the call to rnSrcDecls below
- tcg_dus = emptyDUs }
- ; setGblEnv new_gbl_env $ do {
-
- -- In this situation we want to *shadow* top-level bindings.
- -- foo = 1
- -- bar = [d| foo = 1 |]
- -- If we don't shadow, we'll get an ambiguity complaint when we do
- -- a lookupTopBndrRn (which uses lookupGreLocalRn) on the binder of the 'foo'
- --
- -- Furthermore, arguably if the splice does define foo, that should hide
- -- any foo's further out
- --
- -- The shadowing is acheived by calling rnSrcDecls with True as the shadowing flag
- ; (tcg_env, group') <- rnSrcDecls True group
+ ; let new_gbl_env = gbl_env { tcg_dus = emptyDUs }
+ -- The emptyDUs is so that we just collect uses for this
+ -- group alone in the call to rnSrcDecls below
+ ; (tcg_env, group') <- setGblEnv new_gbl_env $
+ setStage thRnBrack $
+ rnSrcDecls group
-- Discard the tcg_env; it contains only extra info about fixity
- ; return (DecBr group', allUses (tcg_dus tcg_env)) } }
+ ; return (DecBr group', allUses (tcg_dus tcg_env)) }
\end{code}
%************************************************************************
import DynFlags
import HsSyn
+import TcEnv ( isBrackStage )
import RnEnv
import RnHsDoc ( rnHsDoc )
import IfaceEnv ( ifaceExportNames )
* the ImportAvails
created by its bindings.
-Note [Shadowing in extendGlobalRdrEnvRn]
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-Usually when etending the GlobalRdrEnv we complain if a new binding
-duplicates an existing one. By adding the bindings one at a time,
-this check also complains if we add two new bindings for the same name.
-(Remember that in Template Haskell the duplicates might *already be*
-in the GlobalRdrEnv from higher up the module.)
-
-But with a Template Haskell quotation we want to *shadow*:
+Note [Top-level Names in Template Haskell decl quotes]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Consider a Template Haskell declaration quotation like this:
+ module M where
f x = h [d| f = 3 |]
-Here the inner binding for 'f' simply shadows the outer one.
-And that applies even if the binding for 'f' is in a where-clause,
-and hence is in the *local* RdrEnv not the *global* RdrEnv.
+When renaming the declarations inside [d| ...|], we treat the
+top level binders specially in two ways
-Hence the shadowP boolean passed in.
+1. We give them an Internal name, not (as usual) an External one.
+ Otherwise the NameCache gets confused by a second allocation of
+ M.f. (We used to invent a fake module ThFake to avoid this, but
+ that had other problems, notably in getting the correct answer for
+ nameIsLocalOrFrom in lookupFixity. So we now leave tcg_module
+ unaffected.)
+
+2. We make them *shadow* the outer bindings. If we don't do that,
+ we'll get a complaint when extending the GlobalRdrEnv, saying that
+ there are two bindings for 'f'.
+
+ This shadowing applies even if the binding for 'f' is in a
+ where-clause, and hence is in the *local* RdrEnv not the *global*
+ RdrEnv.
+
+We find out whether we are inside a [d| ... |] by testing the TH
+stage. This is a slight hack, because the stage field was really meant for
+the type checker, and here we are not interested in the fields of Brack,
+hence the error thunks in thRnBrack.
\begin{code}
-extendGlobalRdrEnvRn :: Bool -- Note [Shadowing in extendGlobalRdrEnvRn]
- -> [AvailInfo]
+extendGlobalRdrEnvRn :: [AvailInfo]
-> MiniFixityEnv
-> RnM (TcGblEnv, TcLclEnv)
-- Updates both the GlobalRdrEnv and the FixityEnv
-- We return a new TcLclEnv only becuase we might have to
- -- delete some bindings from it; see Note [Shadowing in extendGlobalRdrEnvRn]
+ -- delete some bindings from it;
+ -- see Note [Top-level Names in Template Haskell decl quotes]
-extendGlobalRdrEnvRn shadowP avails new_fixities
+extendGlobalRdrEnvRn avails new_fixities
= do { (gbl_env, lcl_env) <- getEnvs
+ ; stage <- getStage
; let rdr_env = tcg_rdr_env gbl_env
fix_env = tcg_fix_env gbl_env
-- Delete new_occs from global and local envs
- -- We are going to shadow them
- -- See Note [Shadowing in extendGlobalRdrEnvRn]
+ -- If we are in a TemplateHaskell decl bracket,
+ -- we are going to shadow them
+ -- See Note [Top-level Names in Template Haskell decl quotes]
+ shadowP = isBrackStage stage
new_occs = map (nameOccName . gre_name) gres
rdr_env1 = hideSomeUnquals rdr_env new_occs
lcl_env1 = lcl_env { tcl_rdr = delListFromOccEnv (tcl_rdr lcl_env) new_occs }
-
- -- Note [Shadowing in extendGlobalRdrEnvRn]
(rdr_env2, lcl_env2) | shadowP = (rdr_env1, lcl_env1)
| otherwise = (rdr_env, lcl_env)
-- every module that imports the Prelude
| otherwise
= case prov of
- LocalDef -> moduleName (nameModule name) == mod
+ LocalDef | Just name_mod <- nameModule_maybe name
+ -> moduleName name_mod == mod
+ | otherwise -> False
Imported is -> any unQualSpecOK is && any (qualSpecOK mod) is
-------------------------------
\begin{code}
-- Brings the binders of the group into scope in the appropriate places;
-- does NOT assume that anything is in scope already
---
--- The Bool determines whether (True) names in the group shadow existing
--- Unquals in the global environment (used in Template Haskell) or
--- (False) whether duplicates are reported as an error
-rnSrcDecls :: Bool -> HsGroup RdrName -> RnM (TcGblEnv, HsGroup Name)
-
-rnSrcDecls shadowP group@(HsGroup {hs_valds = val_decls,
+rnSrcDecls :: HsGroup RdrName -> RnM (TcGblEnv, HsGroup Name)
+rnSrcDecls group@(HsGroup {hs_valds = val_decls,
hs_tyclds = tycl_decls,
hs_instds = inst_decls,
hs_derivds = deriv_decls,
-- (B) Bring top level binders (and their fixities) into scope,
-- *except* for the value bindings, which get brought in below.
avails <- getLocalNonValBinders group ;
- tc_envs <- extendGlobalRdrEnvRn shadowP avails local_fix_env ;
+ tc_envs <- extendGlobalRdrEnvRn avails local_fix_env ;
setEnvs tc_envs $ do {
failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations
let { lhs_binders = map unLoc $ collectHsValBinders new_lhs;
lhs_avails = map Avail lhs_binders
} ;
- (tcg_env, tcl_env) <- extendGlobalRdrEnvRn shadowP lhs_avails local_fix_env ;
+ (tcg_env, tcl_env) <- extendGlobalRdrEnvRn lhs_avails local_fix_env ;
setEnvs (tcg_env, tcl_env) $ do {
-- Now everything is in scope, as the remaining renaming assumes.
-- Template Haskell stuff
checkWellStaged, spliceOK, bracketOK, tcMetaTy, thLevel,
- topIdLvl, thTopLevelId,
+ topIdLvl, thTopLevelId, thRnBrack, isBrackStage,
-- New Ids
newLocalName, newDFunName, newFamInstTyConName,
Just mod | mod == tcg_mod env -- Names from this module
-> notFound name env -- should be in tcg_type_env
- | mod == thFAKE -- Names bound in TH declaration brackets
- -> notFound name env -- should be in tcg_env
| otherwise
-> tcImportDecl name -- Go find it in an interface
}}}}}
t <- tcLookupTyCon tc_name
return (mkTyConApp t [])
+thRnBrack :: ThStage
+-- Used *only* to indicate that we are inside a TH bracket during renaming
+-- Tested by TcEnv.isBrackStage
+-- This is a slight hack, used to ensure that
+-- * top-level
+thRnBrack = Brack (panic "thRnBrack1") (panic "thRnBrack2") (panic "thRnBrack3")
+
+isBrackStage :: ThStage -> Bool
+isBrackStage (Brack {}) = True
+isBrackStage _other = False
+
thTopLevelId :: Id -> Bool
-- See Note [What is a top-level Id?] in TcSplice
thTopLevelId id = isGlobalId id || isExternalName (idName id)
-- (in fact, it might not even need to be in the scope of
-- this tcg_env at all)
avails <- getLocalNonValBinders (mkFakeGroup ldecls) ;
- tc_envs <- extendGlobalRdrEnvRn False avails
- emptyFsEnv {- no fixity decls -} ;
+ tc_envs <- extendGlobalRdrEnvRn avails emptyFsEnv {- no fixity decls -} ;
setEnvs tc_envs $ do {
rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name)
-- Fails if there are any errors
rnTopSrcDecls group
- = do { -- Rename the source decls (with no shadowing; error on duplicates)
- (tcg_env, rn_decls) <- checkNoErrs $ rnSrcDecls False group ;
+ = do { -- Rename the source decls
+ (tcg_env, rn_decls) <- checkNoErrs $ rnSrcDecls group ;
-- save the renamed syntax, if we want it
let { tcg_env'
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