address compiler warnings gcc-13

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

Author: NikolajBjorner

src/ast/proofs/proof_utils.h

@@ -230,7 +230,7 @@ class elim_aux_assertions {
                    << "New pf: " << mk_pp(newp, m) << "\n";);
         }
 
-        proof *r;
+        proof *r = nullptr;
         VERIFY(cache.find(pr, r));
 
         DEBUG_CODE(

src/ast/simplifiers/dominator_simplifier.cpp

@@ -187,8 +187,8 @@ expr_ref dominator_simplifier::simplify_and_or(bool is_and, app * e) {
 }
 
 expr_ref dominator_simplifier::simplify_not(app * e) {
-    expr *ee;
-    ENSURE(m.is_not(e, ee));
+    expr *ee = nullptr;
+    VERIFY(m.is_not(e, ee));
     unsigned old_lvl = scope_level();
     expr_ref t = simplify_rec(ee);
     local_pop(scope_level() - old_lvl);

src/ast/sls/bv_sls_eval.cpp

@@ -145,7 +145,6 @@ namespace bv {
         SASSERT(m.is_bool(e));
         SASSERT(e->get_family_id() == basic_family_id);
 
-        auto id = e->get_id();
         switch (e->get_decl_kind()) {
         case OP_TRUE:
             return true;

src/muz/spacer/spacer_concretize.cpp

@@ -27,7 +27,7 @@ struct proc {
     void operator()(var *n) const {}
     void operator()(quantifier *q) const {}
     void operator()(app const *n) const {
-        expr *e1, *e2;
+        expr *e1 = nullptr, *e2 = nullptr;
         if (m_arith.is_mul(n, e1, e2)) {
             if (is_var(e1) && !is_var(e2))
                 m_marks.mark(e2);
@@ -71,7 +71,7 @@ bool pob_concretizer::apply(const expr_ref_vector &cube, expr_ref_vector &out) {
 }
 
 bool pob_concretizer::is_split_var(expr *e, expr *&var, bool &pos) {
-    expr *e1, *e2;
+    expr *e1 = nullptr, *e2 = nullptr;
     rational n;
 
     if (m_var_marks.is_marked(e)) {
@@ -89,7 +89,7 @@ bool pob_concretizer::is_split_var(expr *e, expr *&var, bool &pos) {
 }
 
 void pob_concretizer::split_lit_le_lt(expr *_lit, expr_ref_vector &out) {
-    expr *e1, *e2;
+    expr *e1 = nullptr, *e2 = nullptr;
 
     expr *lit = _lit;
     m.is_not(_lit, lit);
@@ -133,7 +133,7 @@ void pob_concretizer::split_lit_le_lt(expr *_lit, expr_ref_vector &out) {
 }
 
 void pob_concretizer::split_lit_ge_gt(expr *_lit, expr_ref_vector &out) {
-    expr *e1, *e2;
+    expr *e1 = nullptr, *e2 = nullptr;
 
     expr *lit = _lit;
     m.is_not(_lit, lit);
@@ -182,7 +182,7 @@ bool pob_concretizer::apply_lit(expr *_lit, expr_ref_vector &out) {
 
     // split literals of the form a1*x1 + ... + an*xn ~ c, where c is a
     // constant, ~ is <, <=, >, or >=, and the top level operator of LHS is +
-    expr *e1, *e2;
+    expr *e1 = nullptr, *e2 = nullptr;
     if ((m_arith.is_lt(lit, e1, e2) || m_arith.is_le(lit, e1, e2)) &&
         m_arith.is_add(e1)) {
         SASSERT(m_arith.is_numeral(e2));

src/nlsat/nlsat_explain.cpp

@@ -126,7 +126,7 @@ namespace nlsat {
         scoped_literal_vector   m_core2;
 
         // temporary fields for storing the result
-        scoped_literal_vector * m_result;
+        scoped_literal_vector * m_result = nullptr;
         svector<char>           m_already_added_literal;
 
         evaluator &             m_evaluator;
@@ -149,8 +149,6 @@ namespace nlsat {
             m_todo(u),
             m_core1(s),
             m_core2(s),
-            m_result(nullptr),
-
             m_cell_sample(is_sample),
 
             m_evaluator(ev) {

src/nlsat/nlsat_simplify.cpp

@@ -93,7 +93,6 @@ namespace nlsat {
         }
 
         void update_clauses(u_map<literal> const& b2l) {
-            bool is_sat = true;
             literal_vector lits;
             unsigned n = m_clauses.size();