diff --git a/src/tactic/sls/sls_tracker.h b/src/tactic/sls/sls_tracker.h
index 5e12faf96..951153a5c 100644
--- a/src/tactic/sls/sls_tracker.h
+++ b/src/tactic/sls/sls_tracker.h
@@ -40,7 +40,9 @@ class sls_tracker {
 
     struct value_score {
     value_score() : m(nullptr), value(unsynch_mpz_manager::mk_z(0)), score(0.0), score_prune(0.0), has_pos_occ(0), has_neg_occ(0), distance(0), touched(1) {};
+        value_score(value_score&&) noexcept = default;
         ~value_score() { if (m) m->del(value); }
+        value_score& operator=(value_score&&) = default;
         unsynch_mpz_manager * m;
         mpz value;
         double score;
diff --git a/src/util/mpq.h b/src/util/mpq.h
index 513dac36e..eef06e2ae 100644
--- a/src/util/mpq.h
+++ b/src/util/mpq.h
@@ -29,6 +29,7 @@ class mpq {
 public:
     mpq(int v):m_num(v), m_den(1) {}
     mpq():m_den(1) {}
+    mpq(mpq &&) noexcept = default;
     mpq & operator=(mpq const &) = delete;
     void swap(mpq & other) { m_num.swap(other.m_num); m_den.swap(other.m_den); }
     mpz const & numerator() const { return m_num; }
diff --git a/src/util/mpz.h b/src/util/mpz.h
index 65380d281..36e6709ee 100644
--- a/src/util/mpz.h
+++ b/src/util/mpz.h
@@ -102,6 +102,15 @@ public:
     mpz(int v):m_val(v), m_kind(mpz_small), m_owner(mpz_self), m_ptr(nullptr) {}
     mpz():m_val(0), m_kind(mpz_small), m_owner(mpz_self), m_ptr(nullptr) {}
     mpz(mpz_type* ptr): m_val(0), m_kind(mpz_small), m_owner(mpz_ext), m_ptr(ptr) { SASSERT(ptr);}
+    mpz(mpz && other) noexcept : m_val(other.m_val), m_kind(other.m_kind), m_owner(other.m_owner), m_ptr(nullptr) {
+        std::swap(m_ptr, other.m_ptr);
+    }
+
+    mpz& operator=(mpz &&other) {
+        swap(other);
+        return *this;
+    }
+
     void swap(mpz & other) { 
         std::swap(m_val, other.m_val);
         std::swap(m_ptr, other.m_ptr);