delete more default constructors

reduces code size by 0.1%

src/math/lp/factorization.h

@@ -24,7 +24,7 @@ class factor {
     factor_type  m_type = factor_type::VAR;
     bool         m_sign = false;
 public:
-    factor() { }
+    factor() = default;
     explicit factor(lpvar v, factor_type t) : m_var(v), m_type(t) {}
     unsigned var() const { return m_var; }
     factor_type type() const { return m_type; }

src/math/lp/indexed_value.h

@@ -29,7 +29,7 @@ public:
     // m_other is the offset of the corresponding element in its vector : for a row element it points to the column element offset,
     // for a column element it points to the row element offset
     unsigned m_other;
-    indexed_value() {}
+    indexed_value() = default;
 
     indexed_value(T v, unsigned i, unsigned other) :
         m_value(v), m_index(i), m_other(other) {

src/math/lp/nex.h

@@ -92,7 +92,7 @@ public:
     virtual const rational& coeff() const { return rational::one(); }
 
     #ifdef Z3DEBUG
-    virtual void sort() {};
+    virtual void sort() {}
     #endif
     bool virtual is_linear() const = 0;
 };

src/math/lp/numeric_pair.h

@@ -116,10 +116,7 @@ template <typename T>
 struct numeric_pair {
     T x;
     T y;
-    // empty constructor
-    numeric_pair() {}
-    // another constructor
-
+    numeric_pair() = default;
     numeric_pair(T xp, T yp) : x(xp), y(yp) {}
 
     template <typename X>

src/math/lp/permutation_matrix.h

@@ -52,7 +52,7 @@ class permutation_matrix
         };
 
     public:
-        permutation_matrix() {}
+        permutation_matrix() = default;
         permutation_matrix(unsigned length);
 
         permutation_matrix(unsigned length, vector<unsigned> const & values);

src/math/lp/stacked_vector.h

@@ -98,9 +98,6 @@ private:
         }
     }
 public:
-
-    stacked_vector() { }
-
     ref operator[] (unsigned a) {
         return ref(*this, a);
     }

src/math/lp/static_matrix.h

@@ -105,7 +105,7 @@ public:
     void init_row_columns(unsigned m, unsigned n);
 
         // constructor with no parameters
-    static_matrix() {}
+    static_matrix() = default;
 
     // constructor
     static_matrix(unsigned m, unsigned n): m_vector_of_row_offsets(n, -1)  {

src/math/lp/var_eqs.h

@@ -81,7 +81,7 @@ class var_eqs {
         
     mutable stats m_stats;
 public:    
-    var_eqs(): m_merge_handler(nullptr), m_uf(*this), m_stack() {}    
+    var_eqs(): m_merge_handler(nullptr), m_uf(*this) {}    
     /**
        \brief push a scope    */
     void push() {

src/math/lp/var_register.h

@@ -27,7 +27,7 @@ class ext_var_info {
     bool m_is_integer;
     std::string m_name;
 public:
-    ext_var_info() {}
+    ext_var_info() = default;
     ext_var_info(unsigned j): ext_var_info(j, true) {}
     ext_var_info(unsigned j , bool is_int) : m_external_j(j), m_is_integer(is_int) {}
     ext_var_info(unsigned j , bool is_int, std::string name) : m_external_j(j), m_is_integer(is_int), m_name(name) {}