[project @ 2001-03-22 11:19:28 by simonpj]

Improve error reporting for signatures not in scope

diff --git a/ghc/compiler/rename/RnEnv.lhs b/ghc/compiler/rename/RnEnv.lhs
index 6ff21b0..e7f101f 100644 (file)
--- a/ghc/compiler/rename/RnEnv.lhs
+++ b/ghc/compiler/rename/RnEnv.lhs
@@ -14,7 +14,7 @@ import HscTypes               ( ModIface(..) )
 import HsSyn
 import RdrHsSyn                ( RdrNameIE )
 import RdrName         ( RdrName, rdrNameModule, rdrNameOcc, isQual, isUnqual, isOrig,
-                         mkRdrUnqual, mkRdrQual, qualifyRdrName, lookupRdrEnv, foldRdrEnv
+                         mkRdrUnqual, mkRdrQual, lookupRdrEnv, foldRdrEnv
                        )
 import HsTypes         ( hsTyVarName, replaceTyVarName )
 import HscTypes                ( Provenance(..), pprNameProvenance, hasBetterProv,
@@ -25,7 +25,7 @@ import HscTypes               ( Provenance(..), pprNameProvenance, hasBetterProv,
                        )
 import RnMonad
 import Name            ( Name,
-                         getSrcLoc, 
+                         getSrcLoc, nameIsLocalOrFrom,
                          mkLocalName, mkGlobalName,
                          mkIPName, nameOccName, nameModule_maybe,
                          setNameModuleAndLoc
@@ -194,16 +194,29 @@ lookupBndrRn rdr_name
          Nothing   -> lookupTopBndrRn rdr_name
 
 lookupTopBndrRn rdr_name
+-- Look up a top-level local binder.   We may be looking up an unqualified 'f',
+-- and there may be several imported 'f's too, which must not confuse us.
+-- So we have to filter out the non-local ones.
+-- A separate function (importsFromLocalDecls) reports duplicate top level
+-- decls, so here it's safe just to choose an arbitrary one.
   = getModeRn  `thenRn` \ mode ->
     if isInterfaceMode mode
        then lookupIfaceName rdr_name   
-       else     -- Source mode, so look up a *qualified* version
-                -- of the name, so that we get the right one even
-                -- if there are many with the same occ name
-                -- There must *be* a binding
-               getModuleRn             `thenRn` \ mod ->
-               getGlobalNameEnv        `thenRn` \ global_env ->
-               lookupSrcName global_env (qualifyRdrName (moduleName mod) rdr_name)
+    else 
+    getModuleRn                `thenRn` \ mod ->
+    getGlobalNameEnv   `thenRn` \ global_env ->
+    case lookup_local mod global_env rdr_name of
+       Just name -> returnRn name
+       Nothing   -> failWithRn (mkUnboundName rdr_name)
+                               (unknownNameErr rdr_name)
+  where
+    lookup_local mod global_env rdr_name
+      = case lookupRdrEnv global_env rdr_name of
+         Nothing   -> Nothing
+         Just gres -> case [n | GRE n _ _ <- gres, nameIsLocalOrFrom mod n] of
+                        []     -> Nothing
+                        (n:ns) -> Just n
+
 
 -- lookupSigOccRn is used for type signatures and pragmas
 -- Is this valid?