From 40317587d007023ec09db8ecab3e1a11f8670649 Mon Sep 17 00:00:00 2001
From: sof <unknown>
Date: Thu, 21 Jan 1999 15:08:51 +0000
Subject: [PATCH] [project @ 1999-01-21 15:08:51 by sof] With Haskell98,
 Enum.enumFromThen can generate sequences that are either
 increasing, decreasing or infinite.

---
 ghc/compiler/typecheck/TcGenDeriv.lhs |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/ghc/compiler/typecheck/TcGenDeriv.lhs b/ghc/compiler/typecheck/TcGenDeriv.lhs
index cc3e205..cab4e7c 100644
--- a/ghc/compiler/typecheck/TcGenDeriv.lhs
+++ b/ghc/compiler/typecheck/TcGenDeriv.lhs
@@ -505,7 +505,12 @@ gen_Enum_binds tycon
 	    HsPar (enum_from_then_to_Expr
 		    (mk_easy_App mkInt_RDR [ah_RDR])
 		    (mk_easy_App mkInt_RDR [bh_RDR])
-		    (HsVar (maxtag_RDR tycon)))
+		    (HsIf  (HsApp (HsApp (HsVar gt_RDR)
+					 (HsVar a_RDR))
+					 (HsVar b_RDR))
+			   (HsLit (HsInt 0))
+			   (HsVar (maxtag_RDR tycon))
+			   tycon_loc))
 
     from_enum
       = mk_easy_FunMonoBind tycon_loc fromEnum_RDR [a_Pat] [] $
-- 
1.7.10.4