diff --git a/src/math/lp/dioph_eq.cpp b/src/math/lp/dioph_eq.cpp
index 46286e35b..b9f41bb48 100644
--- a/src/math/lp/dioph_eq.cpp
+++ b/src/math/lp/dioph_eq.cpp
@@ -1291,7 +1291,6 @@ namespace lp {
                       print_entry(i, tout););
                 CTRACE(
                     "dioph_eq", !entry_invariant(i), tout << "invariant delta:"; {
-                        const auto& e = m_entries[i];
                         print_term_o(get_term_from_entry(ei) -
                                      fix_vars(open_ml(m_l_matrix.m_rows[ei])),
                                      tout)
@@ -1312,7 +1311,6 @@ namespace lp {
         }
 
         bool entry_invariant(unsigned ei) const {
-            const auto& e = m_entries[ei];
             bool ret =
                 term_to_lar_solver(remove_fresh_vars(get_term_from_entry(ei))) ==
                 fix_vars(open_ml(m_l_matrix.m_rows[ei]));
diff --git a/src/math/lp/lp_core_solver_base.h b/src/math/lp/lp_core_solver_base.h
index 32170d6b7..945c1ace3 100644
--- a/src/math/lp/lp_core_solver_base.h
+++ b/src/math/lp/lp_core_solver_base.h
@@ -516,8 +516,8 @@ public:
     }
 
     
-    template <typename T>
-    void swap(T &v, unsigned i, unsigned j) noexcept {
+    template <typename R>
+    void swap(R &v, unsigned i, unsigned j) noexcept {
         auto t = v[i];
         v[i] = v[j];
         v[j] = t;