\begin{code}
module RnEnv (
- newTopSrcBinder,
+ newTopSrcBinder, lookupFamInstDeclBndr,
lookupLocatedBndrRn, lookupBndrRn,
lookupLocatedTopBndrRn, lookupTopBndrRn,
lookupLocatedOccRn, lookupOccRn,
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.
+--
+lookupFamInstDeclBndr :: Module -> Located RdrName -> RnM Name
+lookupFamInstDeclBndr mod lrdr_name@(L _ rdr_name)
+ | not (isSrcRdrName rdr_name)
+ = lookupImportedName rdr_name
+
+ | otherwise
+ = -- First look up the name in the normal environment.
+ lookupGreRn rdr_name `thenM` \ mb_gre ->
+ case mb_gre of {
+ Just gre -> returnM (gre_name gre) ;
+ Nothing -> newTopSrcBinder mod Nothing lrdr_name }
+
--------------------------------------------------
-- Occurrences
--------------------------------------------------