From: Jean Privat <jean@pryen.org>
Date: Sat, 11 Apr 2015 17:12:50 +0000 (+0700)
Subject: lib/ai/backtrack: add a missing assert
X-Git-Tag: v0.7.4~26^2~3
X-Git-Url: http://nitlanguage.org

lib/ai/backtrack: add a missing assert

or else the possible null will loop and cause errors.

Signed-off-by: Jean Privat <jean@pryen.org>
---

diff --git a/lib/ai/backtrack.nit b/lib/ai/backtrack.nit
index 550df10..ddc68ef 100644
--- a/lib/ai/backtrack.nit
+++ b/lib/ai/backtrack.nit
@@ -209,6 +209,7 @@ class BacktrackSolver[S: Object, A]
 
 				problem.backtrack(state, a)
 				node = node.parent
+				assert node != null
 				continue
 			end