module RnSource ( rnDecl, rnHsType, rnHsSigType ) where
+IMPORT_1_3(List(partition))
IMP_Ubiq()
+
+#if defined(__GLASGOW_HASKELL__) && __GLASGOW_HASKELL__ <= 201
IMPORT_DELOOPER(RnLoop) -- *check* the RnPass/RnExpr/RnBinds loop-breaking
-IMPORT_1_3(List(partition))
+#else
+import {-# SOURCE #-} RnExpr
+#endif
import HsSyn
import HsDecls ( HsIdInfo(..) )
import Unique ( Unique )
import UniqSet ( SYN_IE(UniqSet) )
import UniqFM ( UniqFM, lookupUFM )
-import Util {- ( isIn, isn'tIn, thenCmp, removeDups, cmpPString,
- panic, assertPanic{- , pprTrace ToDo:rm-} ) -}
+import Util
+IMPORT_1_3(List(nub))
\end{code}
rnDecl `renames' declarations.
= pushSrcLocRn loc $
lookupBndrRn name `thenRn` \ name' ->
rnHsType ty `thenRn` \ ty' ->
-
- -- Get the pragma info, unless we should ignore it
- (if opt_IgnoreIfacePragmas then
- returnRn []
- else
- setModeRn (InterfaceMode Optional) $
- -- In all the rest of the signature we read in optional mode,
- -- so that (a) we don't die
- mapRn rnIdInfo id_infos
- ) `thenRn` \ id_infos' ->
-
+ -- Get the pragma info (if any).
+ setModeRn (InterfaceMode Optional) $
+ -- In all the rest of the signature we read in optional mode,
+ -- so that (a) we don't die
+ mapRn rnIdInfo id_infos `thenRn` \ id_infos' ->
returnRn (SigD (IfaceSig name' ty' id_infos' loc))
\end{code}
\begin{code}
rnDecl (ClD (ClassDecl context cname tyvar sigs mbinds pragmas src_loc))
= pushSrcLocRn src_loc $
- bindTyVarsRn cls_doc [tyvar] $ \ [tyvar'] ->
- rnContext context `thenRn` \ context' ->
- lookupBndrRn cname `thenRn` \ cname' ->
-
- -- Check the signatures
- checkDupOrQualNames sig_doc sig_names `thenRn_`
- mapRn (rn_op cname' (getTyVarName tyvar')) sigs `thenRn` \ sigs' ->
+ bindTyVarsRn cls_doc [tyvar] ( \ [tyvar'] ->
+ rnContext context `thenRn` \ context' ->
+ lookupBndrRn cname `thenRn` \ cname' ->
+ -- Check the signatures
+ checkDupOrQualNames sig_doc sig_names `thenRn_`
+ mapRn (rn_op cname' (getTyVarName tyvar')) sigs `thenRn` \ sigs' ->
+ returnRn (tyvar', context', cname', sigs')
+ ) `thenRn` \ (tyvar', context', cname', sigs') ->
-- Check the methods
checkDupOrQualNames meth_doc meth_names `thenRn_`
(classTyVarNotInOpTyErr clas_tyvar sig)
`thenRn_`
- -- Check that class tyvar *doesn't* appear in the sig's context
- checkRn (not (clas_tyvar `elemNameSet` ctxt_fvs))
- (classTyVarInOpCtxtErr clas_tyvar sig)
- `thenRn_`
-
returnRn (ClassOpSig op_name dm_name new_ty locn)
\end{code}
-- rnHsSigType is used for source-language type signatures,
-- which use *implicit* universal quantification.
+-- Given the signature C => T we universally quantify over FV(T) \ {in-scope-tyvars}
+--
+-- We insist that the universally quantified type vars is a superset of FV(C)
+-- It follows that FV(T) is a superset of FV(C), so that the context constrains
+-- no type variables that don't appear free in the tau-type part.
+
rnHsSigType doc_str full_ty@(HsPreForAllTy ctxt ty) -- From source code (no kinds on tyvars)
= getNameEnv `thenRn` \ name_env ->
let
- mentioned_tyvars = extractHsTyVars full_ty
- forall_tyvars = filter not_in_scope mentioned_tyvars
- not_in_scope tv = case lookupFM name_env tv of
- Nothing -> True
- Just _ -> False
-
- non_foralld_constrained = [tv | (clas, ty) <- ctxt,
- tv <- extractHsTyVars ty,
- not (tv `elem` forall_tyvars)
- ]
+ mentioned_tyvars = extractHsTyVars ty
+ forall_tyvars = filter (not . in_scope) mentioned_tyvars
+ in_scope tv = maybeToBool (lookupFM name_env tv)
+
+ constrained_tyvars = nub (concat (map (extractHsTyVars . snd) ctxt))
+ constrained_and_in_scope = filter in_scope constrained_tyvars
+ constrained_and_not_mentioned = filter (not . (`elem` mentioned_tyvars)) constrained_tyvars
+
+ -- Zap the context if there's a problem, to avoid duplicate error message.
+ ctxt' | null constrained_and_in_scope && null constrained_and_not_mentioned = ctxt
+ | otherwise = []
in
- checkRn (null non_foralld_constrained)
- (ctxtErr sig_doc non_foralld_constrained) `thenRn_`
+ checkRn (null constrained_and_in_scope)
+ (ctxtErr1 sig_doc constrained_and_in_scope) `thenRn_`
+ checkRn (null constrained_and_not_mentioned)
+ (ctxtErr2 sig_doc constrained_and_not_mentioned ty) `thenRn_`
(bindTyVarsRn sig_doc (map UserTyVar forall_tyvars) $ \ new_tyvars ->
- rnContext ctxt `thenRn` \ new_ctxt ->
+ rnContext ctxt' `thenRn` \ new_ctxt ->
rnHsType ty `thenRn` \ new_ty ->
returnRn (HsForAllTy new_tyvars new_ctxt new_ty)
)
\begin{code}
derivingNonStdClassErr clas sty
- = hsep [ptext SLIT("non-standard class in deriving:"), ppr sty clas]
+ = hsep [ptext SLIT("non-standard class"), ppr sty clas, ptext SLIT("in deriving clause")]
classTyVarNotInOpTyErr clas_tyvar sig sty
- = hang (hcat [ptext SLIT("Class type variable `"),
+ = hang (hsep [ptext SLIT("Class type variable"),
ppr sty clas_tyvar,
- ptext SLIT("' does not appear in method signature:")])
- 4 (ppr sty sig)
-
-classTyVarInOpCtxtErr clas_tyvar sig sty
- = hang (hcat [ ptext SLIT("Class type variable `"), ppr sty clas_tyvar,
- ptext SLIT("' present in method's local overloading context:")])
+ ptext SLIT("does not appear in method signature")])
4 (ppr sty sig)
dupClassAssertWarn ctxt dups sty
allOfNonTyVar ty sty
= hsep [ptext SLIT("`All' applied to a non-type variable:"), ppr sty ty]
-ctxtErr doc tyvars sty
- = hsep [ptext SLIT("Context constrains type variable(s)"),
+ctxtErr1 doc tyvars sty
+ = hsep [ptext SLIT("Context constrains in-scope type variable(s)"),
hsep (punctuate comma (map (ppr sty) tyvars))]
- $$ nest 4 (ptext SLIT("in") <+> doc sty)
+ $$
+ nest 4 (ptext SLIT("in") <+> doc sty)
+
+ctxtErr2 doc tyvars ty sty
+ = (ptext SLIT("Context constrains type variable(s)")
+ <+> hsep (punctuate comma (map (ppr sty) tyvars)))
+ $$
+ nest 4 (vcat [ptext SLIT("that do not appear in") <+> ppr sty ty,
+ ptext SLIT("in") <+> doc sty])
\end{code}
projects / ghc-hetmet.git / blobdiff