add accessors for implied values to API

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

src/tactic/fd_solver/bounded_int2bv_solver.cpp

@@ -361,6 +361,18 @@ private:
         }
     }
 
+    expr_ref get_implied_value(expr* e) override {
+        return expr_ref(e, m);
+    }
+
+    expr_ref get_implied_lower_bound(expr* e) override {
+        return expr_ref(e, m);
+    }
+
+    expr_ref get_implied_upper_bound(expr* e) override {
+        return expr_ref(e, m);
+    }
+
 };
 
 solver * mk_bounded_int2bv_solver(ast_manager & m, params_ref const & p, solver* s) {

src/tactic/fd_solver/enum2bv_solver.cpp

@@ -194,6 +194,18 @@ public:
         return m_solver->get_assertion(idx);
     }
 
+    expr_ref get_implied_value(expr* e) override {
+        return expr_ref(e, m);
+    }
+
+    expr_ref get_implied_lower_bound(expr* e) override {
+        return expr_ref(e, m);
+    }
+
+    expr_ref get_implied_upper_bound(expr* e) override {
+        return expr_ref(e, m);
+    }
+
 };
 
 solver * mk_enum2bv_solver(ast_manager & m, params_ref const & p, solver* s) {

src/tactic/fd_solver/pb2bv_solver.cpp

@@ -147,6 +147,18 @@ public:
         return m_solver->get_assertion(idx);
     }
 
+    expr_ref get_implied_value(expr* e) override {
+        return expr_ref(e, m);
+    }
+
+    expr_ref get_implied_lower_bound(expr* e) override {
+        return expr_ref(e, m);
+    }
+
+    expr_ref get_implied_upper_bound(expr* e) override {
+        return expr_ref(e, m);
+    }
+
 
 private:
     void flush_assertions() const {

src/tactic/fd_solver/smtfd_solver.cpp

@@ -2103,6 +2103,19 @@ namespace smtfd {
         expr * get_assertion(unsigned idx) const override {
             return m_assertions.get(idx);
         }
+
+        expr_ref get_implied_value(expr* e) override {
+            return expr_ref(e, m);
+        }
+        
+        expr_ref get_implied_lower_bound(expr* e) override {
+            return expr_ref(e, m);
+        }
+        
+        expr_ref get_implied_upper_bound(expr* e) override {
+            return expr_ref(e, m);
+        }
+
     };
 
 }