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/ast/ast.h

@@ -1399,6 +1399,7 @@ inline bool has_labels(expr const * n) {
 class some_value_proc {
 public:
     virtual expr * operator()(sort * s) = 0;
+    virtual ~some_value_proc() = default;
 };
 
 // -----------------------------------

src/ast/ast_smt_pp.h

@@ -46,6 +46,7 @@ public:
     public:
         virtual bool operator()(func_decl* d) const { return false; }
         virtual bool operator()(sort* s) const { return false; }
+        virtual ~is_declared() = default;
     };
 private:
     ast_manager& m_manager;

src/ast/fpa/fpa2bv_converter.h

@@ -61,7 +61,7 @@ protected:
 public:
 
     fpa2bv_converter(ast_manager & m);
-    ~fpa2bv_converter();
+    virtual ~fpa2bv_converter();
 
     fpa_util & fu() { return m_util; }
     bv_util & bu() { return m_bv_util; }

src/ast/is_variable_test.h

@@ -23,6 +23,7 @@ Revision History:
 
 class is_variable_proc {
 public:
+    virtual ~is_variable_proc() = default;
     virtual bool operator()(const expr* e) const = 0;
 };
 

src/ast/normal_forms/name_exprs.h

@@ -23,6 +23,7 @@ Notes:
 
 class expr_predicate {
 public:
+    virtual ~expr_predicate() = default;
     virtual bool operator()(expr * t) = 0;
 };
 

src/ast/num_occurs.h

@@ -37,6 +37,8 @@ public:
         m_ignore_quantifiers(ignore_quantifiers) {
     }
 
+    virtual ~num_occurs() = default;
+
     void validate();
     virtual void reset() { m_num_occurs.reset(); }
     

src/ast/recfun_decl_plugin.h

@@ -93,6 +93,7 @@ namespace recfun {
     // closure for computing whether a `rhs` expression is immediate
     struct is_immediate_pred {
         virtual bool operator()(expr * rhs) = 0;
+        virtual ~is_immediate_pred() = default;
     };
 
     class def {

src/ast/rewriter/push_app_ite.h

@@ -33,6 +33,7 @@ struct push_app_ite_cfg : public default_rewriter_cfg {
     virtual bool is_target(func_decl * decl, unsigned num_args, expr * const * args);
     br_status reduce_app(func_decl * f, unsigned num, expr * const * args, expr_ref & result, proof_ref & result_pr);
     push_app_ite_cfg(ast_manager& m): m(m), m_conservative(true) {}
+    virtual ~push_app_ite_cfg() = default;
     void set_conservative(bool c) { m_conservative = c; }
     bool rewrite_patterns() const { return false; }
 };

src/ast/rewriter/seq_eq_solver.h

@@ -39,6 +39,7 @@ namespace seq {
 
     class eq_solver_context {
     public:
+        virtual ~eq_solver_context() = default;
         virtual void  add_consequence(bool uses_dep, expr_ref_vector const& clause) = 0;
         virtual void  add_solution(expr* var, expr* term) = 0;
         virtual expr* expr2rep(expr* e) = 0;

src/ast/rewriter/seq_rewriter.cpp

@@ -3046,7 +3046,6 @@ void seq_rewriter::mk_antimirov_deriv_rec(expr* e, expr* r, expr* path, expr_ref
     auto nothing = [&]() { return expr_ref(re().mk_empty(r->get_sort()), m()); };
     auto epsilon = [&]() { return expr_ref(re().mk_epsilon(seq_sort), m()); };
     auto dotstar = [&]() { return expr_ref(re().mk_full_seq(r->get_sort()), m()); };
-    auto dotplus = [&]() { return expr_ref(re().mk_plus(re().mk_full_char(r->get_sort())), m()); };
     unsigned lo = 0, hi = 0;
     if (re().is_empty(r) || re().is_epsilon(r))
         // D(e,[]) = D(e,()) = []
@@ -3182,7 +3181,7 @@ void seq_rewriter::mk_antimirov_deriv_rec(expr* e, expr* r, expr* path, expr_ref
     else if (re().is_loop(r, r1, lo))
         result = mk_antimirov_deriv_concat(mk_antimirov_deriv(e, r1, path), re().mk_loop(r1, lo - 1));
     else if (re().is_loop(r, r1, lo, hi)) {
-        if (lo == 0 && hi == 0 || hi < lo)
+        if ((lo == 0 && hi == 0) || hi < lo)
             result = nothing();
         else
             result = mk_antimirov_deriv_concat(mk_antimirov_deriv(e, r1, path), re().mk_loop(r1, (lo == 0 ? 0 : lo - 1), hi - 1));
@@ -3260,7 +3259,7 @@ expr_ref seq_rewriter::mk_antimirov_deriv_concat(expr* d, expr* r) {
 }
 
 expr_ref seq_rewriter::mk_antimirov_deriv_negate(expr* d) {
-    sort* seq_sort = nullptr, * ele_sort = nullptr;
+    sort* seq_sort = nullptr;
     VERIFY(m_util.is_re(d, seq_sort));
     auto nothing = [&]() { return expr_ref(re().mk_empty(d->get_sort()), m()); };
     auto epsilon = [&]() { return expr_ref(re().mk_epsilon(seq_sort), m()); };
@@ -3404,7 +3403,7 @@ expr_ref  seq_rewriter::simplify_path(expr* path) {
             result = simplify_path(t);
         else if (m().is_true(t))
             result = simplify_path(h);
-        else if (m().is_eq(h, lhs, rhs) || m().is_not(h, h1) && m().is_eq(h1, lhs, rhs))
+        else if (m().is_eq(h, lhs, rhs) || (m().is_not(h, h1) && m().is_eq(h1, lhs, rhs)))
             elim_condition(lhs, result);
     }
     return result;