diff --git a/src/opt/maxsmt.cpp b/src/opt/maxsmt.cpp
index 97b6a5293..f93291599 100644
--- a/src/opt/maxsmt.cpp
+++ b/src/opt/maxsmt.cpp
@@ -55,15 +55,18 @@ namespace opt {
 
     void maxsmt_solver_base::commit_assignment() {
         expr_ref tmp(m);
-        rational k(0);
+        rational k(0), cost(0);
         for (unsigned i = 0; i < m_soft.size(); ++i) {
             if (get_assignment(i)) {
                 k += m_weights[i];
             }
+            else {
+                cost += m_weights[i];
+            }
         }       
         pb_util pb(m);
         tmp = pb.mk_ge(m_weights.size(), m_weights.c_ptr(), m_soft.c_ptr(), k);
-        TRACE("opt", tout << tmp << "\n";);
+        TRACE("opt", tout << "cost: " << cost << "\n" << tmp << "\n";);
         s().assert_expr(tmp);
     }
 
@@ -140,7 +143,9 @@ namespace opt {
         m_wth = s.ensure_wmax_theory();
     }
     maxsmt_solver_base::scoped_ensure_theory::~scoped_ensure_theory() {
-        //m_wth->reset_local();
+        if (m_wth) {
+            m_wth->reset_local();
+        }
     }
     smt::theory_wmaxsat& maxsmt_solver_base::scoped_ensure_theory::operator()() { return *m_wth; }
 
@@ -226,7 +231,9 @@ namespace opt {
         m_msolver = 0;
         symbol const& maxsat_engine = m_c.maxsat_engine();
         IF_VERBOSE(1, verbose_stream() << "(maxsmt)\n";);
-        TRACE("opt", tout << "maxsmt\n";);
+        TRACE("opt", tout << "maxsmt\n";
+              s().display(tout); tout << "\n";
+              );
         if (m_soft_constraints.empty() || maxsat_engine == symbol("maxres") || maxsat_engine == symbol::null) {            
             m_msolver = mk_maxres(m_c, m_index, m_weights, m_soft_constraints);
         }
diff --git a/src/opt/opt_solver.cpp b/src/opt/opt_solver.cpp
index 42129be70..351141a3f 100644
--- a/src/opt/opt_solver.cpp
+++ b/src/opt/opt_solver.cpp
@@ -327,12 +327,7 @@ namespace opt {
         SASSERT(idx < get_num_assertions());
         return m_context.get_formulas()[idx];
     }
-    
-    std::ostream& opt_solver::display(std::ostream & out) const {
-        m_context.display(out);
-        return out;
-    }
-    
+        
     smt::theory_var opt_solver::add_objective(app* term) {
         smt::theory_var v = get_optimizer().add_objective(term);
         m_objective_vars.push_back(v);
diff --git a/src/opt/opt_solver.h b/src/opt/opt_solver.h
index cdaad3cf2..27168e2ca 100644
--- a/src/opt/opt_solver.h
+++ b/src/opt/opt_solver.h
@@ -104,7 +104,6 @@ namespace opt {
         virtual void set_progress_callback(progress_callback * callback);
         virtual unsigned get_num_assertions() const;
         virtual expr * get_assertion(unsigned idx) const;
-        virtual std::ostream& display(std::ostream & out) const;
         virtual ast_manager& get_manager() const { return m; } 
         virtual lbool find_mutexes(expr_ref_vector const& vars, vector<expr_ref_vector>& mutexes);
         virtual lbool preferred_sat(expr_ref_vector const& asms, vector<expr_ref_vector>& cores);
diff --git a/src/opt/wmax.cpp b/src/opt/wmax.cpp
index 690e2000b..9708bdc8f 100644
--- a/src/opt/wmax.cpp
+++ b/src/opt/wmax.cpp
@@ -64,6 +64,7 @@ namespace opt {
             bool was_sat = false;
             expr_ref_vector asms(m);
             vector<expr_ref_vector> cores;
+
             obj_map<expr, rational>::iterator it = soft.begin(), end = soft.end();
             for (; it != end; ++it) {
                 expr* c = assert_weighted(wth(), it->m_key, it->m_value);
diff --git a/src/sat/sat_solver.cpp b/src/sat/sat_solver.cpp
index eec94879a..37fb971fd 100644
--- a/src/sat/sat_solver.cpp
+++ b/src/sat/sat_solver.cpp
@@ -3227,20 +3227,32 @@ namespace sat {
         SASSERT(!inconsistent());
         unsigned sz = m_trail.size();
         for (unsigned i = start; i < sz && lvl(m_trail[i]) <= 1; ++i) {
-            extract_fixed_consequences(m_trail[i], assumptions, unfixed, conseq);
+            if (!extract_fixed_consequences(m_trail[i], assumptions, unfixed, conseq)) {
+                for (i = 0; i < sz && lvl(m_trail[i]) <= 1; ++i) {
+                    VERIFY(extract_fixed_consequences(m_trail[i], assumptions, unfixed, conseq));
+                }
+                break;
+            }
         }
         start = sz;
     }
 
-    void solver::extract_assumptions(literal lit, index_set& s) {
+    bool solver::check_domain(literal lit, literal lit2) {
+        return m_antecedents.contains(lit2.var());
+    }
+
+    bool solver::extract_assumptions(literal lit, index_set& s) {
         justification js = m_justification[lit.var()];
         switch (js.get_kind()) {
         case justification::NONE:
             break;
         case justification::BINARY:
+            if (!check_domain(lit, js.get_literal())) return false;
             s |= m_antecedents.find(js.get_literal().var());
             break;
         case justification::TERNARY:
+            if (!check_domain(lit, js.get_literal1())) return false;
+            if (!check_domain(lit, js.get_literal2())) return false;
             s |= m_antecedents.find(js.get_literal1().var());
             s |= m_antecedents.find(js.get_literal2().var());
             break;
@@ -3248,6 +3260,7 @@ namespace sat {
             clause & c = *(m_cls_allocator.get_clause(js.get_clause_offset()));
             for (unsigned i = 0; i < c.size(); ++i) {
                 if (c[i] != lit) {
+                    if (!check_domain(lit, c[i])) return false;
                     s |= m_antecedents.find(c[i].var());
                 }
             }
@@ -3258,6 +3271,7 @@ namespace sat {
             literal_vector::iterator it  = m_ext_antecedents.begin();
             literal_vector::iterator end = m_ext_antecedents.end();
             for (; it != end; ++it) {
+                if (!check_domain(lit, *it)) return false;
                 s |= m_antecedents.find(it->var());
             }
             break;
@@ -3267,6 +3281,7 @@ namespace sat {
             break;
         }
         TRACE("sat", display_index_set(tout << lit << ": " , s) << "\n";);
+        return true;
     }
 
     std::ostream& solver::display_index_set(std::ostream& out, index_set const& s) const {
@@ -3279,17 +3294,19 @@ namespace sat {
     }
 
 
-    void solver::extract_fixed_consequences(literal lit, literal_set const& assumptions, bool_var_set& unfixed, vector<literal_vector>& conseq) {
+    bool solver::extract_fixed_consequences(literal lit, literal_set const& assumptions, bool_var_set& unfixed, vector<literal_vector>& conseq) {
         index_set s;
         if (m_antecedents.contains(lit.var())) {
-            return;
+            return true;
         }
         if (assumptions.contains(lit)) {
             s.insert(lit.index());
         }
         else {
+            if (!extract_assumptions(lit, s)) {
+                return false;
+            }
             add_assumption(lit);
-            extract_assumptions(lit, s);
         }
         m_antecedents.insert(lit.var(), s);
         if (unfixed.contains(lit.var())) {
@@ -3302,6 +3319,7 @@ namespace sat {
             unfixed.remove(lit.var());
             conseq.push_back(cons);
         }
+        return true;
     }
 
     void solver::asymmetric_branching() {
diff --git a/src/sat/sat_solver.h b/src/sat/sat_solver.h
index f28d0aa5b..dcf7e2acb 100644
--- a/src/sat/sat_solver.h
+++ b/src/sat/sat_solver.h
@@ -439,7 +439,9 @@ namespace sat {
         u_map<index_set>       m_antecedents;
         vector<literal_vector> m_binary_clause_graph;
 
-        void extract_assumptions(literal lit, index_set& s);
+        bool extract_assumptions(literal lit, index_set& s);
+        
+        bool check_domain(literal lit, literal lit2);
 
         std::ostream& display_index_set(std::ostream& out, index_set const& s) const;
 
@@ -451,7 +453,7 @@ namespace sat {
 
         void extract_fixed_consequences(unsigned& start, literal_set const& assumptions, bool_var_set& unfixed, vector<literal_vector>& conseq);
 
-        void extract_fixed_consequences(literal lit, literal_set const& assumptions, bool_var_set& unfixed, vector<literal_vector>& conseq);
+        bool extract_fixed_consequences(literal lit, literal_set const& assumptions, bool_var_set& unfixed, vector<literal_vector>& conseq);
 
         void update_unfixed_literals(literal_set& unfixed_lits, bool_var_set& unfixed_vars);
 
diff --git a/src/smt/smt_context.cpp b/src/smt/smt_context.cpp
index ea97d1a64..c7aecca88 100644
--- a/src/smt/smt_context.cpp
+++ b/src/smt/smt_context.cpp
@@ -1795,6 +1795,7 @@ namespace smt {
 
     void context::set_conflict(b_justification js, literal not_l) {
         if (!inconsistent()) {
+            TRACE("set_conflict", display_literal_verbose(tout, not_l); display(tout, js); );
             m_conflict = js;
             m_not_l    = not_l;
         }