src: remove extraneous operator!= definitions

Since C++20, overload resolution for `a != b` considers
rewritten candidate operator==.

Author: jengelh

exch/http/http_parser.cpp

@@ -147,7 +147,6 @@ class VCONN_REF {
 		pvconnection(p), m_hold(p->lock), m_iter(std::move(i)) {}
 	~VCONN_REF() { put(); }
 	NOMOVE(VCONN_REF);
-	bool operator!=(std::nullptr_t) const { return pvconnection != nullptr; }
 	bool operator==(std::nullptr_t) const { return pvconnection == nullptr; }
 	void put();
 	VIRTUAL_CONNECTION *operator->() { return pvconnection; }

exch/mysql_adaptor/sql2.hpp

@@ -27,7 +27,6 @@ class sqlconn final {
 	sqlconn &operator=(sqlconn &&o) noexcept;
 	operator bool() const { return m_conn; }
 	bool operator==(std::nullptr_t) const { return m_conn == nullptr; }
-	bool operator!=(std::nullptr_t) const { return m_conn != nullptr; }
 	MYSQL *get() const { return m_conn; }
 	std::string quote(std::string_view);
 	bool query(std::string_view);

include/gromox/common_types.hpp

@@ -9,14 +9,12 @@ struct GX_EXPORT BOOL {
 	constexpr BOOL() noexcept = default;
 	constexpr BOOL(int z) noexcept : m_bool_value{z} {}
 	constexpr bool operator==(const BOOL &o) const noexcept { return m_bool_value == o.m_bool_value; }
-	constexpr bool operator!=(const BOOL &o) const noexcept { return m_bool_value != o.m_bool_value; }
 	constexpr bool operator!() const noexcept { return !m_bool_value; }
 	constexpr operator bool() const noexcept { return m_bool_value; }
 	constexpr operator int() const noexcept = delete;
 #endif
 };
 inline bool operator==(const BOOL &a, const BOOL &b) { return a.v == b.v; }
-inline bool operator!=(const BOOL &a, const BOOL &b) { return a.v != b.v; }
 inline bool operator!(const BOOL &a) { return !a.v; }
 static constexpr BOOL FALSE{0};
 static constexpr BOOL TRUE{-1};

include/gromox/database_mysql.hpp

@@ -33,7 +33,6 @@ class GX_EXPORT DB_RESULT {
 	}
 	operator bool() const noexcept { return m_res != nullptr; }
 	bool operator==(std::nullptr_t) const noexcept { return m_res == nullptr; }
-	bool operator!=(std::nullptr_t) const noexcept { return m_res != nullptr; }
 	MYSQL_RES *get() const noexcept { return m_res; }
 	void *release() noexcept
 	{

include/gromox/defs.h

@@ -196,7 +196,6 @@ template<typename T> struct deref_iterator {
 	constexpr deref_iterator(T **p = nullptr) : ptr(p) {}
 	constexpr T &operator*() { return **ptr; }
 	constexpr bool operator==(const deref_iterator o) const { return ptr == o.ptr; }
-	constexpr bool operator!=(const deref_iterator o) const { return ptr != o.ptr; }
 	constexpr deref_iterator &operator--() { --ptr; return *this; }
 	constexpr deref_iterator &operator++() { ++ptr; return *this; }
 };
@@ -206,7 +205,6 @@ template<typename T> struct const_deref_iterator {
 	constexpr const_deref_iterator(T **p = nullptr) : ptr(p) {}
 	constexpr const T &operator*() { return **ptr; }
 	constexpr bool operator==(const const_deref_iterator &o) const { return ptr == o.ptr; }
-	constexpr bool operator!=(const const_deref_iterator &o) const { return ptr != o.ptr; }
 	constexpr const_deref_iterator &operator--() { --ptr; return *this; }
 	constexpr const_deref_iterator &operator++() { ++ptr; return *this; }
 };

include/gromox/exmdb_client.hpp

@@ -71,7 +71,6 @@ struct GX_EXPORT remote_conn_ref {
 	void operator=(remote_conn &&) = delete;
 	remote_conn *operator->() { return tmplist.size() != 0 ? &tmplist.front() : nullptr; }
 	bool operator==(std::nullptr_t) const { return tmplist.size() == 0; }
-	bool operator!=(std::nullptr_t) const { return tmplist.size() != 0; }
 	void reset(bool lost = false);
 
 	std::list<remote_conn> tmplist;

include/gromox/mapidefs.h

@@ -951,7 +951,6 @@ struct GX_EXPORT FLATUID {
 	 * `!=` needs to be explicit before C++20.
 	 */
 	inline bool operator==(const FLATUID &o) const { return memcmp(ab, o.ab, sizeof(ab)) == 0; }
-	inline bool operator!=(const FLATUID &o) const { return !operator==(o); }
 };
 
 struct GX_EXPORT FLATUID_ARRAY {
@@ -997,7 +996,6 @@ struct GX_EXPORT GUID {
 	 * call memcmp directly.
 	 */
 	inline bool operator==(const GUID &o) const { return memcmp(this, &o, sizeof(o)) == 0; }
-	inline bool operator!=(const GUID &o) const { return !operator==(o); }
 	/*
 	 * EXC2019 evaluates GUID-GUID comparisons (in e.g. restrictions)
 	 * member-wise and in host order.

include/gromox/mapierr.hpp

@@ -442,7 +442,6 @@ struct GX_EXPORT ec_error_t {
 	constexpr ec_error_t(ec_error_t_ll x) : m_value(x) {}
 	constexpr ec_error_t(int) = delete;
 	constexpr bool operator==(ec_error_t_ll x) const { return m_value == x; }
-	constexpr bool operator!=(ec_error_t_ll x) const { return m_value != x; }
 	constexpr operator bool() const = delete;
 	constexpr void operator!() const = delete;
 	constexpr operator uint32_t() const { return m_value; }

mra/midb_agent.cpp

@@ -65,7 +65,6 @@ struct BACK_CONN_floating {
 	void operator=(BACK_CONN_floating &&) = delete;
 	BACK_CONN *operator->() { return tmplist.size() != 0 ? &tmplist.front() : nullptr; }
 	bool operator==(std::nullptr_t) const { return tmplist.size() == 0; }
-	bool operator!=(std::nullptr_t) const { return tmplist.size() != 0; }
 	void reset(bool lost = false);
 
 	std::list<BACK_CONN> tmplist;