fix #4131

Author: NikolajBjorner

src/smt/diff_logic.h

@@ -264,13 +264,11 @@ class dl_graph {
 public:
     // An assignment is feasible if all edges are feasible.
     bool is_feasible() const {
-#ifdef Z3DEBUG
         for (unsigned i = 0; i < m_edges.size(); ++i) {
             if (!is_feasible(m_edges[i])) {
                 return false;
             }
         }
-#endif
         return true;
     }
 

src/smt/theory_diff_logic_def.h

@@ -341,9 +341,8 @@ void theory_diff_logic<Ext>::pop_scope_eh(unsigned num_scopes) {
     m_scopes.shrink(new_lvl);
     unsigned num_edges = m_graph.get_num_edges();
     m_graph.pop(num_scopes);
-    TRACE("arith", m_graph.display(tout););
-    SASSERT(m_graph.is_feasible());
-    if (true || (num_edges != m_graph.get_num_edges() && m_num_simplex_edges > 0)) {
+    CTRACE("arith", !m_graph.is_feasible(), m_graph.display(tout););
+    if (num_edges != m_graph.get_num_edges() && m_num_simplex_edges > 0) {
         m_S.reset();
         m_num_simplex_edges = 0;
         m_objective_rows.reset();