Merge remote-tracking branch 'origin/master' into c3

# Conflicts:
#	.github/workflows/qf-s-benchmark.lock.yml
#	.github/workflows/qf-s-benchmark.md
#	.github/workflows/zipt-code-reviewer.lock.yml
#	.github/workflows/zipt-code-reviewer.md
#	.gitignore
#	src/ast/rewriter/seq_rewriter.cpp
#	src/test/main.cpp

src/ast/rewriter/bit2int.cpp

@@ -354,8 +354,8 @@ void bit2int::visit(app* n) {
         //
         // (pos1 - neg1) mod e2 = (pos1 + (e2 - (neg1 mod e2))) mod e2
         //
-        unsigned sz_p, sz_n, sz;
-        bool sign_p, sign_n;
+        unsigned sz_p = 0, sz_n = 0, sz;
+        bool sign_p = false, sign_n = false;
         expr_ref tmp_p(m), tmp_n(m);
         VERIFY(extract_bv(pos1, sz_p, sign_p, tmp_p));
         VERIFY(extract_bv(neg1, sz_n, sign_n, tmp_n));

src/ast/rewriter/enum2bv_rewriter.cpp

@@ -64,7 +64,7 @@ struct enum2bv_rewriter::imp {
             unsigned bv_size = get_bv_size(s);
             sort_ref bv_sort(m_bv.mk_sort(bv_size), m);
             if (is_unate(s))
-                return m_bv.mk_numeral(rational((1 << idx) - 1), bv_sort.get());
+                return m_bv.mk_numeral(rational((1u << idx) - 1), bv_sort.get());
             else 
                 return m_bv.mk_numeral(rational(idx), bv_sort.get());
         }

src/ast/rewriter/seq_eq_solver.cpp

@@ -226,7 +226,6 @@ namespace seq {
         return
             e.ls.size() == 1 && e.rs.size() == 1 &&
             seq.str.is_ubv2s(e.ls[0], a) && seq.str.is_ubv2s(e.rs[0], b);
-        return false;
     }
 
     bool eq_solver::reduce_ubv2s1(eqr const& e, eq_ptr& r) {

src/ast/rewriter/seq_rewriter.cpp

@@ -4391,6 +4391,8 @@ br_status seq_rewriter::mk_str_in_regexp(expr* a, expr* b, expr_ref& result) {
     return BR_FAILED;
     // disabled
 
+#if 0
+    
     expr_ref hd(m()), tl(m());
     if (get_head_tail(a, hd, tl)) {
         //result = re().mk_in_re(tl, re().mk_derivative(hd, b));
@@ -4430,6 +4432,8 @@ br_status seq_rewriter::mk_str_in_regexp(expr* a, expr* b, expr_ref& result) {
         return BR_REWRITE_FULL;
     }
 
+#endif
+
 #if 0
     unsigned len = 0;
     if (has_fixed_length_constraint(b, len)) {