diff --git a/src/util/lp/sparse_matrix.h b/src/util/lp/sparse_matrix.h
index 7db526bdd..400f2bfc0 100644
--- a/src/util/lp/sparse_matrix.h
+++ b/src/util/lp/sparse_matrix.h
@@ -302,11 +302,11 @@ public:
     void solve_U_y_indexed_only(indexed_vector<L> & y, const lp_settings&, vector<unsigned> & sorted_active_rows );
 
 #ifdef Z3DEBUG
-    T get_elem(unsigned i, unsigned j) const override { return get(i, j); }
-    unsigned get_number_of_rows() const override { return dimension(); }
-    unsigned get_number_of_columns() const override { return dimension(); }
-    virtual void set_number_of_rows(unsigned /*m*/) override { }
-    virtual void set_number_of_columns(unsigned /*n*/) override { }
+    T get_elem(unsigned i, unsigned j) const { return get(i, j); }
+    unsigned get_number_of_rows() const { return dimension(); }
+    unsigned get_number_of_columns() const { return dimension(); }
+    virtual void set_number_of_rows(unsigned /*m*/) { }
+    virtual void set_number_of_columns(unsigned /*n*/) { }
 #endif
     template <typename L>
     L dot_product_with_row (unsigned row, const vector<L> & y) const;