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) }
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
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}