Commit 6a562dd5 authored by simonpj's avatar simonpj
Browse files

[project @ 2000-07-14 13:38:39 by simonpj]

Arrange that type signatures work right.  Consider:

	   module A
		import M( f )
		f :: Int -> Int
		f x = x

Here, the 'f' in the signature isn't ambiguous; it
refers to the locally defined f.  (This isn't clear in
the Haskell 98 report, but it will be.)
parent 71352675
......@@ -224,8 +224,8 @@ 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 "a binding group") mbinders_w_srclocs
$ \ new_mbinders ->
bindLocatedLocalsRn (text "a binding group")
mbinders_w_srclocs $ \ new_mbinders ->
let
binder_set = mkNameSet new_mbinders
in
......
......@@ -24,7 +24,7 @@ import Name ( Name, Provenance(..), ExportFlag(..), NamedThing(..),
mkLocalName, mkImportedLocalName, mkGlobalName, mkUnboundName,
mkIPName, isWiredInName, hasBetterProv,
nameOccName, setNameModule, nameModule,
pprOccName, isLocallyDefined, nameUnique, nameOccName,
pprOccName, isLocallyDefined, nameUnique,
setNameProvenance, getNameProvenance, pprNameProvenance,
extendNameEnv_C, plusNameEnv_C, nameEnvElts
)
......@@ -322,6 +322,13 @@ bindCoreLocalsFVRn (b:bs) thing_inside = bindCoreLocalFVRn b $ \ name' ->
bindCoreLocalsFVRn bs $ \ names' ->
thing_inside (name':names')
bindLocalNames names enclosed_scope
= getLocalNameEnv `thenRn` \ name_env ->
setLocalNameEnv (addListToRdrEnv name_env pairs)
enclosed_scope
where
pairs = [(mkRdrUnqual (nameOccName n), n) | n <- names]
-------------------------------------
bindLocalRn doc rdr_name enclosed_scope
= getSrcLocRn `thenRn` \ loc ->
......@@ -350,15 +357,10 @@ bindUVarRn = bindLocalRn
extendTyVarEnvFVRn :: [HsTyVarBndr Name] -> RnMS (a, FreeVars) -> RnMS (a, FreeVars)
-- This tiresome function is used only in rnDecl on InstDecl
extendTyVarEnvFVRn tyvars enclosed_scope
= getLocalNameEnv `thenRn` \ env ->
let
tyvar_names = hsTyVarNames tyvars
new_env = addListToRdrEnv env [ (mkRdrUnqual (getOccName name), name)
| name <- tyvar_names
]
in
setLocalNameEnv new_env enclosed_scope `thenRn` \ (thing, fvs) ->
= bindLocalNames tyvar_names enclosed_scope `thenRn` \ (thing, fvs) ->
returnRn (thing, delListFromNameSet fvs tyvar_names)
where
tyvar_names = hsTyVarNames tyvars
bindTyVarsRn :: SDoc -> [HsTyVarBndr RdrName]
-> ([HsTyVarBndr Name] -> RnMS a)
......@@ -474,38 +476,13 @@ lookupGlobalOccRn rdr_name
-- import M( f )
-- f :: Int -> Int
-- f x = x
-- In a sense, it's clear that the 'f' in the signature must refer
-- to A.f, but the Haskell98 report does not stipulate this, so
-- I treat the 'f' in the signature as a reference to an unqualified
-- 'f' and hence fail with an ambiguous reference.
-- It's clear that the 'f' in the signature must refer to A.f
-- The Haskell98 report does not stipulate this, but it will!
-- So we must treat the 'f' in the signature in the same way
-- as the binding occurrence of 'f', using lookupBndrRn
lookupSigOccRn :: RdrName -> RnMS Name
lookupSigOccRn = lookupOccRn
{- OLD VERSION
-- This code tries to be cleverer than the above.
-- The variable in a signature must refer to a locally-defined thing,
-- even if there's an imported thing of the same name.
--
-- But this doesn't work for instance decls:
-- instance Enum Int where
-- {-# INLINE enumFrom #-}
-- ...
-- Here the enumFrom is an imported reference!
lookupSigOccRn rdr_name
= getNameEnvs `thenRn` \ (global_env, local_env) ->
case (lookupRdrEnv local_env rdr_name, lookupRdrEnv global_env rdr_name) of
(Just name, _) -> returnRn name
(Nothing, Just names) -> case filter isLocallyDefined names of
[n] -> returnRn n
ns -> pprPanic "lookupSigOccRn" (ppr rdr_name <+> ppr names <+> ppr ns)
-- There can't be a local top-level name-clash
-- (That's dealt with elsewhere.)
(Nothing, Nothing) -> failWithRn (mkUnboundName rdr_name)
(unknownNameErr rdr_name)
-}
lookupSigOccRn = lookupBndrRn
-- Look in both local and global env
lookup_occ global_env local_env rdr_name
......
......@@ -25,7 +25,7 @@ import RnEnv ( bindTyVarsRn, lookupBndrRn, lookupOccRn, getIPName,
lookupImplicitOccRn, lookupImplicitOccsRn,
bindLocalsRn, bindLocalRn, bindLocalsFVRn, bindUVarRn,
bindTyVarsFVRn, bindTyVarsFV2Rn, extendTyVarEnvFVRn,
bindCoreLocalFVRn, bindCoreLocalsFVRn,
bindCoreLocalFVRn, bindCoreLocalsFVRn, bindLocalNames,
checkDupOrQualNames, checkDupNames,
mkImportedGlobalName, mkImportedGlobalFromRdrName,
newDFunName, getDFunKey, newImplicitBinder,
......@@ -299,14 +299,19 @@ rnDecl (InstD (InstDecl inst_ty mbinds uprags dfun_rdr_name src_loc))
rnMethodBinds mbinds
) `thenRn` \ (mbinds', meth_fvs) ->
let
binders = mkNameSet (map fst (bagToList (collectMonoBinders mbinds')))
binders = map fst (bagToList (collectMonoBinders mbinds'))
binder_set = mkNameSet binders
in
-- Rename the prags and signatures.
-- Note that the type variables are not in scope here,
-- so that instance Eq a => Eq (T a) where
-- {-# SPECIALISE instance Eq a => Eq (T [a]) #-}
-- works OK.
renameSigs (okInstDclSig binders) uprags `thenRn` \ (new_uprags, prag_fvs) ->
--
-- But the (unqualified) method names are in scope
bindLocalNames binders (
renameSigs (okInstDclSig binder_set) uprags
) `thenRn` \ (new_uprags, prag_fvs) ->
getModeRn `thenRn` \ mode ->
(case mode of
......
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