Revert "Fix warnings from GCC 12.0.1"

example/plugins/cpp-api/boom/boom.cc

@@ -98,16 +98,13 @@ GlobalPlugin *plugin;
 // Functor that decides whether the HTTP error can be rewritten or not.
 // Rewritable codes are: 2xx, 3xx, 4xx, 5xx and 6xx.
 // 1xx is NOT rewritable!
-class IsRewritableCode
+class IsRewritableCode : public std::unary_function<std::string, bool>
 { // could probably be replaced with mem_ptr_fun()..
 private:
   int current_code_;
   std::string current_code_string_;
 
 public:
-  using argument_type = std::string;
-  using result_type   = bool;
-
   explicit IsRewritableCode(int current_code) : current_code_(current_code)
   {
     std::ostringstream oss;

include/tscore/IntrusivePtr.h

@@ -330,13 +330,9 @@ template <typename T> class IntrusivePtrDefaultPolicy
   static void finalize(T *t);
 
   /// Strict weak order for STL containers.
-  class Order
+  class Order : public std::binary_function<IntrusivePtr<T>, IntrusivePtr<T>, bool>
   {
   public:
-    using first_argument_type  = IntrusivePtr<T>;
-    using second_argument_type = IntrusivePtr<T>;
-    using result_type          = bool;
-
     /// Default constructor.
     Order() {}
     /// Compare by raw pointer.

include/tscpp/api/Headers.h

@@ -109,15 +109,12 @@ class HeaderField;
 /**
  * @brief A header field value iterator iterates through all header fields.
  */
-class header_field_value_iterator
+class header_field_value_iterator : public std::iterator<std::forward_iterator_tag, int>
 {
 private:
   HeaderFieldValueIteratorState *state_;
 
 public:
-  using iterator_category = std::forward_iterator_tag;
-  using value_type        = int;
-
   /**
    * Constructor for header_field_value_iterator, this shouldn't need to be used directly.
    * @param bufp the TSMBuffer associated with the headers
@@ -172,16 +169,13 @@ class header_field_value_iterator
 /**
  * @brief A header field iterator is an iterator that dereferences to a HeaderField.
  */
-class header_field_iterator
+class header_field_iterator : public std::iterator<std::forward_iterator_tag, int>
 {
 private:
   HeaderFieldIteratorState *state_;
   header_field_iterator(void *hdr_buf, void *hdr_loc, void *field_loc);
 
 public:
-  using iterator_category = std::forward_iterator_tag;
-  using value_type        = int;
-
   ~header_field_iterator();
 
   /**

iocore/net/quic/QUICFrame.h

@@ -204,12 +204,9 @@ class QUICAckFrame : public QUICFrame
   class AckBlockSection
   {
   public:
-    class const_iterator
+    class const_iterator : public std::iterator<std::input_iterator_tag, QUICAckFrame::AckBlock>
     {
     public:
-      using iterator_category = std::input_iterator_tag;
-      using value_type        = QUICAckFrame::AckBlock;
-
       const_iterator(uint8_t index, const std::vector<QUICAckFrame::AckBlock> *ack_blocks);
 
       const QUICAckFrame::AckBlock &

lib/swoc/include/swoc/DiscreteRange.h

@@ -319,11 +319,7 @@ template <typename T> class DiscreteRange {
       The first pair of elements that are not equal determine the ordering
       of the overall tuples.
    */
-  struct lexicographic_order {
-    using first_argument_type = self_type;
-    using second_argument_type = self_type;
-    using result_type = bool;
-
+  struct lexicographic_order : public std::binary_function<self_type, self_type, bool> {
     //! Functor operator.
     bool operator()(self_type const &lhs, self_type const &rhs) const;
   };

src/tscore/HostLookup.cc

@@ -231,11 +231,7 @@ struct CharIndexBlock {
 class CharIndex
 {
 public:
-  struct iterator {
-    using iterator_category = std::forward_iterator_tag;
-    using value_type        = HostBranch;
-    using difference_type   = int;
-
+  struct iterator : public std::iterator<std::forward_iterator_tag, HostBranch, int> {
     using self_type = iterator;
 
     struct State {

src/wccp/WccpMeta.h

@@ -54,11 +54,7 @@ template <bool VALUE> struct TEST_IF_TRUE : public TEST_RESULT<TEST_BOOL<VALUE>>
 };
 
 // Helper for assigning a value to all instances in a container.
-template <typename T, typename R, typename A1> struct TsAssignMember {
-  using first_argument_type  = T;
-  using second_argument_type = A1;
-  using result_type          = R;
-
+template <typename T, typename R, typename A1> struct TsAssignMember : public std::binary_function<T, A1, R> {
   R T::*_m;
   A1 _arg1;
   TsAssignMember(R T::*m, A1 const &arg1) : _m(m), _arg1(arg1) {}