fix build warnings

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

src/math/lp/column.h

@@ -45,7 +45,6 @@ class column {
     u_dependency* m_lower_bound_witness = nullptr;
     u_dependency* m_upper_bound_witness = nullptr;
     bool          m_associated_with_row = false;  
-    lpvar         m_j; //the column index
     lar_term*     m_term = nullptr;
 public:
     lar_term*  term() const { return m_term; }

src/qe/qsat.cpp

@@ -1014,7 +1014,6 @@ namespace qe {
                 case AST_APP: {
                     app* a = to_app(e);
                     expr_ref_vector args(m);
-                    unsigned num_args = a->get_num_args();
                     bool all_visited = true;
                     for (expr* arg : *a) {
                         if (visited.find(arg, r)) {

src/sat/smt/q_solver.cpp

@@ -120,7 +120,6 @@ namespace q {
     }
 
     sat::literal solver::instantiate(quantifier* _q, bool negate, std::function<expr* (quantifier*, unsigned)>& mk_var) {
-        sat::literal sk;
         expr_ref tmp(m);
         quantifier_ref q(_q, m);
         expr_ref_vector vars(m);

src/smt/theory_seq.cpp

@@ -1270,7 +1270,6 @@ bool theory_seq::solve_nc(unsigned idx) {
     expr_ref c(m);
     expr* a = nullptr, *b = nullptr;
     VERIFY(m_util.str.is_contains(n.contains(), a, b));
-    literal pre, cnt, ctail, emp;
     lbool is_gt = ctx.get_assignment(len_gt);
     TRACE("seq", ctx.display_literal_smt2(tout << len_gt << " := " << is_gt << "\n", len_gt) << "\n";);