From 2d20db7e6d187135c5d5e51d13c0afd1deff5378 Mon Sep 17 00:00:00 2001
From: Vitor Santos Costa <vsc@dcc.fc.up.pt>
Date: Sat, 14 Feb 2015 17:05:48 +0000
Subject: [PATCH] protect against mal-formed calls

---
 pl/modules.yap | 1 +
 1 file changed, 1 insertion(+)

diff --git a/pl/modules.yap b/pl/modules.yap
index 9d31ebfcd..53d648256 100644
--- a/pl/modules.yap
+++ b/pl/modules.yap
@@ -838,6 +838,7 @@ expand_goal(G, G).
 	'$continue_imported'(ExportingMod, ExportingModI, G0, G0I).
 % SWI builtin
 '$get_undefined_pred'(G, _ImportingMod, G, user) :-
+	nonvar(G),
 	'$pred_exists'(G, user), !.
 '$get_undefined_pred'(G, _ImportingMod, G0, ExportingMod) :-
         recorded('$dialect',Dialect,_),