Add and fix a few general compiler warnings. (#5628)

* rewriter: fix unused variable warnings

* cmake: make missing non-virtual dtors error

* treewide: add missing virtual destructors

* cmake: add a few more checks

* api: add missing virtual destructor to user_propagator_base

* examples: compile cpp example with compiler warnings

* model: fix unused variable warnings

* rewriter: fix logical-op-parentheses warnings

* sat: fix unused variable warnings

* smt: fix unused variable warnings

src/math/hilbert/heap_trie.h

@@ -270,6 +270,7 @@ public:
     class check_value {
     public:
         virtual bool operator()(Value const& v) = 0;
+        virtual ~check_value() = default;
     };
 
     bool find_le(Key const* keys, check_value& check) {

src/math/lp/column_namer.h

@@ -23,6 +23,7 @@ Revision History:
 namespace lp {
 class column_namer {
 public:
+    virtual ~column_namer() = default;
     virtual std::string get_variable_name(unsigned j) const = 0;
     template <typename T>
     std::ostream & print_row(const row_strip<T> & row, std::ostream & out) const {

src/math/lp/factorization.h

@@ -120,6 +120,8 @@ struct factorization_factory {
         m_vars(vars), m_monic(m) {
     }
 
+    virtual ~factorization_factory() = default;
+
     bool_vector get_mask() const {
         // we keep the last element always in the first factor to avoid
         // repeating a pair twice, that is why m_mask is shorter by one then m_vars

src/math/lp/lp_settings.h

@@ -99,6 +99,7 @@ template <typename X> bool is_epsilon_small(const X & v, const double& eps);
 
 class lp_resource_limit {
 public:
+    virtual ~lp_resource_limit() = default;
     virtual bool get_cancel_flag() = 0;
 };
 

src/math/polynomial/polynomial.h

@@ -71,6 +71,7 @@ namespace polynomial {
     template<typename ValManager, typename Value = typename ValManager::numeral>
     class var2value {
     public:
+        virtual ~var2value() = default;
         virtual ValManager & m() const = 0;
         virtual bool contains(var x) const = 0;
         virtual Value const & operator()(var x) const = 0;
@@ -100,6 +101,7 @@ namespace polynomial {
 
     struct display_var_proc {
         virtual std::ostream& operator()(std::ostream & out, var x) const { return out << "x" << x; }
+        virtual ~display_var_proc() = default;
     };
 
     class polynomial;
@@ -228,6 +230,7 @@ namespace polynomial {
             del_eh * m_next;
         public:
             del_eh():m_next(nullptr) {}
+            virtual ~del_eh() = default;
             virtual void operator()(polynomial * p) = 0;
         };
 

src/math/polynomial/upolynomial_factorization_int.h

@@ -175,6 +175,8 @@ namespace upolynomial {
             m_current_size = 0;
         }
 
+        virtual ~factorization_combination_iterator_base() = default;
+
         /**
            \brief Returns the factors we are enumerating through.
         */

src/math/realclosure/realclosure.h

@@ -37,6 +37,7 @@ namespace realclosure {
 
     class mk_interval {
     public:
+        virtual ~mk_interval() = default;
         virtual void operator()(unsigned k, mpqi_manager & im, mpqi_manager::interval & r) = 0;
     };
 

src/math/subpaving/subpaving_types.h

@@ -42,6 +42,7 @@ public:
 };
 
 struct display_var_proc {
+    virtual ~display_var_proc() = default;
     virtual void operator()(std::ostream & out, var x) const { out << "x" << x; }
 };