From f371fca6c56d8396c9e98e971dd0eac8df55b1f0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?V=C3=ADtor=20Santos=20Costa?= <vsc@dcc.fc.up.pt>
Date: Thu, 8 Nov 2012 00:19:48 +0000
Subject: [PATCH] check if defined

---
 pl/boot.yap | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pl/boot.yap b/pl/boot.yap
index d74d72ad6..6985b7e3b 100755
--- a/pl/boot.yap
+++ b/pl/boot.yap
@@ -903,7 +903,7 @@ not(G) :-    \+ '$execute'(G).
 '$call'(G, CP, G0, CurMod) :-
 	( '$is_expand_goal_or_meta_predicate'(G,CurMod) ->
 	   (
-	     '$notrace'((CurMod:goal_expansion(G,NG) ;  system:goal_expansion(G,NG) ; user:goal_expansion(G, CurMod, NG) ; user:goal_expansion(G,NG) )) ->
+	     '$notrace'(('$pred_exists'(goal_expansion(G,NG), CurMod), CurMod:goal_expansion(G,NG) ;  system:goal_expansion(G,NG) ; user:goal_expansion(G, CurMod, NG) ; user:goal_expansion(G,NG) )) ->
 	       '$call'(NG, CP, G0,CurMod)
 	     ;
 	       % repeat other code.