[project @ 2000-07-18 14:50:32 by simonpj]

[ghc-hetmet.git] / ghc / compiler / rename / RnEnv.lhs

diff --git a/ghc/compiler/rename/RnEnv.lhs b/ghc/compiler/rename/RnEnv.lhs
index 15a46bf..80b6174 100644 (file)
--- a/ghc/compiler/rename/RnEnv.lhs
+++ b/ghc/compiler/rename/RnEnv.lhs
@@ -452,7 +452,14 @@ lookupBndrRn rdr_name
                case lookupRdrEnv global_env (qualifyRdrName mod rdr_name) of
                  Just (name:rest) -> ASSERT( null rest )
                                      returnRn name 
-                 Nothing          -> pprPanic "lookupBndrRn" (ppr mod <+> ppr rdr_name)
+                 Nothing          ->   -- Almost always this case is a compiler bug.
+                                       -- But consider a type signature that doesn't have 
+                                       -- a corresponding binder: 
+                                       --      module M where { f :: Int->Int }
+                                       -- We use lookupSigOccRn, which uses lookupBndrRn (for good reasons)
+                                       -- and we don't want to panic.  So we report an out-of-scope error
+                                       failWithRn (mkUnboundName rdr_name)
+                                                  (unknownNameErr rdr_name)
     }
 
 -- lookupOccRn looks up an occurrence of a RdrName