Fix issue with reset-assertions. (#3988)

Calling (reset-assertions) in start mode was not handled correctly.
Additionally, when calling (check-sat) after (reset-assertions) after a
(check-sat) call that answered unsat, we answered unsat instead of sat.
This cleans up and fixes reset-assertions) handling.

3 files changed, 9 insertions, 6 deletions

diff --git a/src/prop/minisat/minisat.h b/src/prop/minisat/minisat.h
index 3cc0ed120..f00bba000 100644
--- a/src/prop/minisat/minisat.h
+++ b/src/prop/minisat/minisat.h
@@ -27,8 +27,7 @@ class MinisatSatSolver : public DPLLSatSolverInterface {
 public:
 
   MinisatSatSolver(StatisticsRegistry* registry);
-  virtual ~MinisatSatSolver();
-;
+  ~MinisatSatSolver() override;
 
   static SatVariable     toSatVariable(Minisat::Var var);
   static Minisat::Lit    toMinisatLit(SatLiteral lit);
diff --git a/src/prop/prop_engine.cpp b/src/prop/prop_engine.cpp
index 546567b98..19ee29191 100644
--- a/src/prop/prop_engine.cpp
+++ b/src/prop/prop_engine.cpp
@@ -120,6 +120,7 @@ PropEngine::PropEngine(TheoryEngine* te,
 PropEngine::~PropEngine() {
   Debug("prop") << "Destructing the PropEngine" << endl;
   d_decisionEngine->shutdown();
+  d_decisionEngine.reset(nullptr);
   delete d_cnfStream;
   delete d_registrar;
   delete d_satSolver;
diff --git a/src/prop/sat_solver.h b/src/prop/sat_solver.h
index 9898f3f87..b9c518fd6 100644
--- a/src/prop/sat_solver.h
+++ b/src/prop/sat_solver.h
@@ -132,10 +132,13 @@ public:
 
 };/* class BVSatSolverInterface */
 
+class DPLLSatSolverInterface : public SatSolver
+{
+ public:
+  virtual ~DPLLSatSolverInterface(){};
 
-class DPLLSatSolverInterface: public SatSolver {
-public:
-  virtual void initialize(context::Context* context, prop::TheoryProxy* theoryProxy) = 0;
+  virtual void initialize(context::Context* context,
+                          prop::TheoryProxy* theoryProxy) = 0;
 
   virtual void push() = 0;
 
@@ -152,7 +155,7 @@ public:
   virtual void requirePhase(SatLiteral lit) = 0;
 
   virtual bool isDecision(SatVariable decn) const = 0;
-};/* class DPLLSatSolverInterface */
+}; /* class DPLLSatSolverInterface */
 
 inline std::ostream& operator <<(std::ostream& out, prop::SatLiteral lit) {
   out << lit.toString();