[project @ 1997-11-25 10:52:29 by simonm]

fix for "TyCon used as Class" bug.

diff --git a/ghc/compiler/typecheck/TcEnv.lhs b/ghc/compiler/typecheck/TcEnv.lhs
index 32fdf22..e406b28 100644 (file)
--- a/ghc/compiler/typecheck/TcEnv.lhs
+++ b/ghc/compiler/typecheck/TcEnv.lhs
@@ -55,6 +55,7 @@ import UniqFM
 import Util            ( zipEqual, zipWithEqual, zipWith3Equal, zipLazy,
                          panic, pprPanic, pprTrace
                        )
+import Maybes          ( maybeToBool )
 import Outputable
 \end{code}
 
@@ -175,14 +176,17 @@ tcLookupTyConByKey uniq
 
 tcLookupClass name
   = tcGetEnv           `thenNF_Tc` \ (TcEnv tve tce ce gve lve gtvs) ->
---  pprTrace "tcLookupClass:" (hsep [text "Uniq:", pprUnique10 (uniqueOf name), text "; avail:", hsep (map (pprUnique10 . fst) (ufmToList ce))]) $
---  pprTrace "tcLookupClass:" (hsep [text "Uniq:", pprUnique (uniqueOf name), text "; avail:", hsep (map (pprUnique . fst) (ufmToList ce))]) $
     case lookupUFM ce name of
-       Just stuff -> returnTc stuff
-       Nothing    ->   -- Could be that he's using a type constructor as a class
-                       case lookupUFM tce name of
-                         Just _ ->  failTc (tyConAsClassErr name)
-                         Nothing -> pprPanic "tcLookupClass:" (ppr PprShowAll name)
+       Just stuff         -- Common case: it's ok
+         -> returnTc stuff
+
+       Nothing            -- Could be that he's using a type constructor as a class
+         |  maybeToBool (maybeWiredInTyConName name)
+         || maybeToBool (lookupUFM tce name)
+         -> failTc (tyConAsClassErr name)
+
+         | otherwise      -- Wierd!  Renamer shouldn't let this happen
+         -> pprPanic "tcLookupClass:" (ppr PprShowAll name)
 
 tcLookupClassByKey uniq
   = tcGetEnv           `thenNF_Tc` \ (TcEnv tve tce ce gve lve gtvs) ->