[project @ 1999-05-07 13:41:14 by sof]

Fixed two showstopping bugs in 'deriving Read' code (mea culpa).

diff --git a/ghc/compiler/typecheck/TcGenDeriv.lhs b/ghc/compiler/typecheck/TcGenDeriv.lhs
index e017cf2..bb27993 100644 (file)
--- a/ghc/compiler/typecheck/TcGenDeriv.lhs
+++ b/ghc/compiler/typecheck/TcGenDeriv.lhs
@@ -840,7 +840,7 @@ gen_Read_binds fixities tycon
                                 ])
              | lab_fields == 0 =  -- common case.
                  snd (mapAccumL mk_qual 
-                                c_Expr 
+                                d_Expr 
                                 (zipWithEqual "as_needed" 
                                               (\ con_field draw_from -> (mk_read_qual 10 con_field,
                                                                          draw_from))
@@ -891,8 +891,9 @@ gen_Read_binds fixities tycon
             | not is_infix  = 9
             | otherwise     = getFixity fixities dc_nm
 
-          read_paren_arg  = -- parens depend on precedence...
-            HsPar (genOpApp a_Expr gt_RDR (HsLit (HsInt paren_prec_limit)))
+          read_paren_arg   -- parens depend on precedence...
+           | nullary_con  = false_Expr -- it's optional.
+           | otherwise    = HsPar (genOpApp a_Expr gt_RDR (HsLit (HsInt paren_prec_limit)))
 
 \end{code}