diff --git a/Triangulation_2/include/CGAL/Constrained_triangulation_plus_2.h b/Triangulation_2/include/CGAL/Constrained_triangulation_plus_2.h
index edb9279e791..1e0c27333ab 100644
--- a/Triangulation_2/include/CGAL/Constrained_triangulation_plus_2.h
+++ b/Triangulation_2/include/CGAL/Constrained_triangulation_plus_2.h
@@ -739,9 +739,9 @@ public:
     for(auto it = vertices.begin(), succ = it; ++succ != vertices.end(); ++it){
       if(! is_subconstraint(*it, *succ)){ // this checks whether other constraints pass
         Face_handle fh;
-        int i;
-        bool b = Triangulation::is_edge(*it, *succ, fh, i);
-        CGAL_assume(b);
+        int i = -1;
+        Triangulation::is_edge(*it, *succ, fh, i);
+        CGAL_assertion(i != -1);
         Triangulation::remove_constrained_edge(fh,i, out); // this does also flipping if necessary.
       }
     }