#5778 - missed tracking literal assignment justification

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

src/ast/euf/euf_egraph.cpp

@@ -293,11 +293,12 @@ namespace euf {
        VERIFY(n->num_args() == 0 || !n->merge_enabled() || m_table.contains(n));
     }
 
-    void egraph::set_value(enode* n, lbool value) {  
+    void egraph::set_value(enode* n, lbool value, justification j) {  
         if (n->value() == l_undef) {
             force_push();
             TRACE("euf", tout << bpp(n) << " := " << value << "\n";);
             n->set_value(value);
+            n->set_justification(j);
             m_updates.push_back(update_record(n, update_record::value_assignment()));
         }
     }
@@ -657,6 +658,7 @@ namespace euf {
             push_lca(n1->get_arg(1), n2->get_arg(0));
             return;
         }
+        TRACE("euf_verbose", tout << bpp(n1) << " " << bpp(n2) << "\n");
 
         for (unsigned i = 0; i < n1->num_args(); ++i) 
             push_lca(n1->get_arg(i), n2->get_arg(i));
@@ -713,6 +715,15 @@ namespace euf {
         explain_todo(justifications);
     }
 
+    template <typename T>
+    void egraph::explain_eq(ptr_vector<T>& justifications, enode* a, enode* b, justification const& j) {
+        if (j.is_external())
+            justifications.push_back(j.ext<T>());
+        else if (j.is_congruence()) 
+            push_congruence(a, b, j.is_commutative());
+    }
+
+
     template <typename T>
     void egraph::explain_eq(ptr_vector<T>& justifications, enode* a, enode* b) {
         SASSERT(a->get_root() == b->get_root());
@@ -746,11 +757,21 @@ namespace euf {
     void egraph::explain_todo(ptr_vector<T>& justifications) {
         for (unsigned i = 0; i < m_todo.size(); ++i) {
             enode* n = m_todo[i];
-            if (n->m_target && !n->is_marked1()) {
+            if (n->is_marked1())
+                continue;
+            if (n->m_target) {
                 n->mark1();
                 CTRACE("euf_verbose", m_display_justification, n->m_justification.display(tout << n->get_expr_id() << " = " << n->m_target->get_expr_id() << " ", m_display_justification) << "\n";);
                 explain_eq(justifications, n, n->m_target, n->m_justification);
             }
+            else if (!n->is_marked1() && n->value() != l_undef) {
+                n->mark1();
+                if (m.is_true(n->get_expr()) || m.is_false(n->get_expr()))
+                    continue;
+                justification j = n->m_justification;
+                SASSERT(j.is_external());
+                justifications.push_back(j.ext<T>());
+            }
         }
     }
 

src/ast/euf/euf_egraph.h

@@ -226,12 +226,8 @@ namespace euf {
         void erase_from_table(enode* p);
 
         template <typename T>
-        void explain_eq(ptr_vector<T>& justifications, enode* a, enode* b, justification const& j) {
-            if (j.is_external())
-                justifications.push_back(j.ext<T>());
-            else if (j.is_congruence()) 
-                push_congruence(a, b, j.is_commutative());
-        }
+        void explain_eq(ptr_vector<T>& justifications, enode* a, enode* b, justification const& j);
+
         template <typename T>
         void explain_todo(ptr_vector<T>& justifications);
 
@@ -295,7 +291,7 @@ namespace euf {
         void add_th_var(enode* n, theory_var v, theory_id id);
         void set_th_propagates_diseqs(theory_id id);
         void set_merge_enabled(enode* n, bool enable_merge);
-        void set_value(enode* n, lbool value);
+        void set_value(enode* n, lbool value, justification j);
         void set_bool_var(enode* n, unsigned v) { n->set_bool_var(v); }
         void set_relevant(enode* n);
         void set_default_relevant(bool b) { m_default_relevant = b; }

src/ast/euf/euf_enode.h

@@ -133,6 +133,7 @@ namespace euf {
         void del_th_var(theory_id id) { m_th_vars.del_var(id); }   
         void set_merge_enabled(bool m) { m_merge_enabled = m; }
         void set_value(lbool v) { m_value = v; }
+        void set_justification(justification j) { m_justification = j; }
         void set_is_equality() { m_is_equality = true;  }
         void set_bool_var(sat::bool_var v) { m_bool_var = v; }
 

src/sat/smt/euf_internalize.cpp

@@ -190,8 +190,9 @@ namespace euf {
         m_egraph.set_bool_var(n, v);
         if (m.is_eq(e) || m.is_or(e) || m.is_and(e) || m.is_not(e))
             m_egraph.set_merge_enabled(n, false);
-        if (s().value(lit) != l_undef) 
-            m_egraph.set_value(n, s().value(lit));
+        lbool val = s().value(lit);
+        if (val != l_undef) 
+            m_egraph.set_value(n, val, justification::external(to_ptr(val == l_true ? lit : ~lit)));
         return lit;
     }
 

src/sat/smt/euf_solver.cpp

@@ -309,7 +309,7 @@ namespace euf {
         if (!n)
             return;
         bool sign = l.sign();   
-        m_egraph.set_value(n, sign ? l_false : l_true);
+        m_egraph.set_value(n, sign ? l_false : l_true, justification::external(to_ptr(l)));
         for (auto const& th : enode_th_vars(n))
             m_id2solver[th.get_id()]->asserted(l);