Implement LWG 2934, optional<const T> doesn't compare with T.

* include/std/optional
(operator==(const optional<_Tp>&, const optional<_Tp>&)):
Turn into operator==(const optional<_Tp>&, const optional<_Up>&).
(operator!=(const optional<_Tp>&, const optional<_Tp>&)):
Turn into operator!=(const optional<_Tp>&, const optional<_Up>&).
(operator<(const optional<_Tp>&, const optional<_Tp>&)):
Turn into operator<(const optional<_Tp>&, const optional<_Up>&.
(operator>(const optional<_Tp>&, const optional<_Tp>&)):
Turn into operator>(const optional<_Tp>&, const optional<_Up>&.
(operator<=(const optional<_Tp>&, const optional<_Tp>&)):
Turn into operator<=(const optional<_Tp>&, const optional<_Up>&).
(operator>=(const optional<_Tp>&, const optional<_Tp>&)):
Turn into operator>=(const optional<_Tp>&, const optional<_Up>&).
(operator==(const optional<_Tp>&, const _Tp&)):
Turn into operator==(const optional<_Tp>&, const _Up&).
(operator==(const _Tp&, const optional<_Tp>&)):
Turn into operator==(const _Up&, const optional<_Tp>&).
(operator!=(const optional<_Tp>&, const _Tp&)):
Turn into operator!=(const optional<_Tp>&, const _Up&).
(operator!=(const _Tp&, const optional<_Tp>&)):
Turn into operator!=(const _Up&, const optional<_Tp>&).
(operator<(const optional<_Tp>&, const _Tp&)):
Turn into operator<(const optional<_Tp>&, const _Up&).
(operator<(const _Tp&, const optional<_Tp>&)):
Turn into operator<(const _Up&, const optional<_Tp>&).
(operator>(const optional<_Tp>&, const _Tp&)):
Turn into operator>(const optional<_Tp>&, const _Up&).
(operator>(const _Tp&, const optional<_Tp>&)):
Turn into operator>(const _Up&, const optional<_Tp>&).
(operator<=(const optional<_Tp>&, const _Tp&)):
Turn into operator<=(const optional<_Tp>&, const _Up&).
(operator<=(const _Tp&, const optional<_Tp>&)):
Turn into operator<=(const _Up&, const optional<_Tp>&).
(operator>=(const optional<_Tp>&, const _Tp&)):
Turn into operator>=(const optional<_Tp>&, const _Up&).
(operator>=(const _Tp&, const optional<_Tp>&)):
Turn into operator>=(const _Up&, const optional<_Tp>&).
* testsuite/20_util/optional/relops/7.cc: New.

From-SVN: r246076

3 files changed, 168 insertions, 54 deletions

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index ee0ae99..520c05c 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,45 @@
+2017-03-12  Ville Voutilainen  <ville.voutilainen@gmail.com>
+
+	Implement LWG 2934, optional<const T> doesn't compare with T.
+	* include/std/optional
+	(operator==(const optional<_Tp>&, const optional<_Tp>&)):
+	Turn into operator==(const optional<_Tp>&, const optional<_Up>&).
+	(operator!=(const optional<_Tp>&, const optional<_Tp>&)):
+	Turn into operator!=(const optional<_Tp>&, const optional<_Up>&).
+	(operator<(const optional<_Tp>&, const optional<_Tp>&)):
+	Turn into operator<(const optional<_Tp>&, const optional<_Up>&.
+	(operator>(const optional<_Tp>&, const optional<_Tp>&)):
+	Turn into operator>(const optional<_Tp>&, const optional<_Up>&.
+	(operator<=(const optional<_Tp>&, const optional<_Tp>&)):
+	Turn into operator<=(const optional<_Tp>&, const optional<_Up>&).
+	(operator>=(const optional<_Tp>&, const optional<_Tp>&)):
+	Turn into operator>=(const optional<_Tp>&, const optional<_Up>&).
+	(operator==(const optional<_Tp>&, const _Tp&)):
+	Turn into operator==(const optional<_Tp>&, const _Up&).
+	(operator==(const _Tp&, const optional<_Tp>&)):
+	Turn into operator==(const _Up&, const optional<_Tp>&).
+	(operator!=(const optional<_Tp>&, const _Tp&)):
+	Turn into operator!=(const optional<_Tp>&, const _Up&).
+	(operator!=(const _Tp&, const optional<_Tp>&)):
+	Turn into operator!=(const _Up&, const optional<_Tp>&).
+	(operator<(const optional<_Tp>&, const _Tp&)):
+	Turn into operator<(const optional<_Tp>&, const _Up&).
+	(operator<(const _Tp&, const optional<_Tp>&)):
+	Turn into operator<(const _Up&, const optional<_Tp>&).
+	(operator>(const optional<_Tp>&, const _Tp&)):
+	Turn into operator>(const optional<_Tp>&, const _Up&).
+	(operator>(const _Tp&, const optional<_Tp>&)):
+	Turn into operator>(const _Up&, const optional<_Tp>&).
+	(operator<=(const optional<_Tp>&, const _Tp&)):
+	Turn into operator<=(const optional<_Tp>&, const _Up&).
+	(operator<=(const _Tp&, const optional<_Tp>&)):
+	Turn into operator<=(const _Up&, const optional<_Tp>&).
+	(operator>=(const optional<_Tp>&, const _Tp&)):
+	Turn into operator>=(const optional<_Tp>&, const _Up&).
+	(operator>=(const _Tp&, const optional<_Tp>&)):
+	Turn into operator>=(const _Up&, const optional<_Tp>&).
+	* testsuite/20_util/optional/relops/7.cc: New.
+
 2017-03-10  Jonathan Wakely  <jwakely@redhat.com>
 
 	* testsuite/17_intro/names.cc: Undefine macros that clash with
diff --git a/libstdc++-v3/include/std/optional b/libstdc++-v3/include/std/optional
index 905bc0a..c700515 100644
--- a/libstdc++-v3/include/std/optional
+++ b/libstdc++-v3/include/std/optional
@@ -737,52 +737,52 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     enable_if_t<is_convertible<_Tp, bool>::value, bool>;
 
   // Comparisons between optional values.
-  template<typename _Tp>
+  template<typename _Tp, typename _Up>
     constexpr auto
-    operator==(const optional<_Tp>& __lhs, const optional<_Tp>& __rhs)
-    -> __optional_relop_t<decltype(declval<_Tp>() == declval<_Tp>())>
+    operator==(const optional<_Tp>& __lhs, const optional<_Up>& __rhs)
+    -> __optional_relop_t<decltype(declval<_Tp>() == declval<_Up>())>
     {
       return static_cast<bool>(__lhs) == static_cast<bool>(__rhs)
 	     && (!__lhs || *__lhs == *__rhs);
     }
 
-  template<typename _Tp>
+  template<typename _Tp, typename _Up>
     constexpr auto
-    operator!=(const optional<_Tp>& __lhs, const optional<_Tp>& __rhs)
-    -> __optional_relop_t<decltype(declval<_Tp>() != declval<_Tp>())>
+    operator!=(const optional<_Tp>& __lhs, const optional<_Up>& __rhs)
+    -> __optional_relop_t<decltype(declval<_Tp>() != declval<_Up>())>
     {
       return static_cast<bool>(__lhs) != static_cast<bool>(__rhs)
 	|| (static_cast<bool>(__lhs) && *__lhs != *__rhs);
     }
 
-  template<typename _Tp>
+  template<typename _Tp, typename _Up>
     constexpr auto
-    operator<(const optional<_Tp>& __lhs, const optional<_Tp>& __rhs)
-    -> __optional_relop_t<decltype(declval<_Tp>() < declval<_Tp>())>
+    operator<(const optional<_Tp>& __lhs, const optional<_Up>& __rhs)
+    -> __optional_relop_t<decltype(declval<_Tp>() < declval<_Up>())>
     {
       return static_cast<bool>(__rhs) && (!__lhs || *__lhs < *__rhs);
     }
 
-  template<typename _Tp>
+  template<typename _Tp, typename _Up>
     constexpr auto
-    operator>(const optional<_Tp>& __lhs, const optional<_Tp>& __rhs)
-    -> __optional_relop_t<decltype(declval<_Tp>() > declval<_Tp>())>
+    operator>(const optional<_Tp>& __lhs, const optional<_Up>& __rhs)
+    -> __optional_relop_t<decltype(declval<_Tp>() > declval<_Up>())>
     {
       return static_cast<bool>(__lhs) && (!__rhs || *__lhs > *__rhs);
     }
 
-  template<typename _Tp>
+  template<typename _Tp, typename _Up>
     constexpr auto
-    operator<=(const optional<_Tp>& __lhs, const optional<_Tp>& __rhs)
-    -> __optional_relop_t<decltype(declval<_Tp>() <= declval<_Tp>())>
+    operator<=(const optional<_Tp>& __lhs, const optional<_Up>& __rhs)
+    -> __optional_relop_t<decltype(declval<_Tp>() <= declval<_Up>())>
     {
       return !__lhs || (static_cast<bool>(__rhs) && *__lhs <= *__rhs);
     }
 
-  template<typename _Tp>
+  template<typename _Tp, typename _Up>
     constexpr auto
-    operator>=(const optional<_Tp>& __lhs, const optional<_Tp>& __rhs)
-    -> __optional_relop_t<decltype(declval<_Tp>() >= declval<_Tp>())>
+    operator>=(const optional<_Tp>& __lhs, const optional<_Up>& __rhs)
+    -> __optional_relop_t<decltype(declval<_Tp>() >= declval<_Up>())>
     {
       return !__rhs || (static_cast<bool>(__lhs) && *__lhs >= *__rhs);
     }
@@ -849,76 +849,76 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     { return !__rhs; }
 
   // Comparisons with value type.
-  template<typename _Tp>
+  template<typename _Tp, typename _Up>
     constexpr auto
-    operator==(const optional<_Tp>& __lhs, const _Tp& __rhs)
-    -> __optional_relop_t<decltype(declval<_Tp>() == declval<_Tp>())>
+    operator==(const optional<_Tp>& __lhs, const _Up& __rhs)
+    -> __optional_relop_t<decltype(declval<_Tp>() == declval<_Up>())>
     { return __lhs && *__lhs == __rhs; }
 
-  template<typename _Tp>
+  template<typename _Tp, typename _Up>
     constexpr auto
-    operator==(const _Tp& __lhs, const optional<_Tp>& __rhs)
-    -> __optional_relop_t<decltype(declval<_Tp>() == declval<_Tp>())>
+    operator==(const _Up& __lhs, const optional<_Tp>& __rhs)
+    -> __optional_relop_t<decltype(declval<_Up>() == declval<_Tp>())>
     { return __rhs && __lhs == *__rhs; }
 
-  template<typename _Tp>
+  template<typename _Tp, typename _Up>
     constexpr auto
-    operator!=(const optional<_Tp>& __lhs, const _Tp& __rhs)
-    -> __optional_relop_t<decltype(declval<_Tp>() != declval<_Tp>())>
+    operator!=(const optional<_Tp>& __lhs, const _Up& __rhs)
+    -> __optional_relop_t<decltype(declval<_Tp>() != declval<_Up>())>
     { return !__lhs || *__lhs != __rhs; }
 
-  template<typename _Tp>
+  template<typename _Tp, typename _Up>
     constexpr auto
-    operator!=(const _Tp& __lhs, const optional<_Tp>& __rhs)
-    -> __optional_relop_t<decltype(declval<_Tp>() != declval<_Tp>())>
+    operator!=(const _Up& __lhs, const optional<_Tp>& __rhs)
+    -> __optional_relop_t<decltype(declval<_Up>() != declval<_Tp>())>
     { return !__rhs || __lhs != *__rhs; }
 
-  template<typename _Tp>
+  template<typename _Tp, typename _Up>
     constexpr auto
-    operator<(const optional<_Tp>& __lhs, const _Tp& __rhs)
-    -> __optional_relop_t<decltype(declval<_Tp>() < declval<_Tp>())>
+    operator<(const optional<_Tp>& __lhs, const _Up& __rhs)
+    -> __optional_relop_t<decltype(declval<_Tp>() < declval<_Up>())>
     { return !__lhs || *__lhs < __rhs; }
 
-  template<typename _Tp>
+  template<typename _Tp, typename _Up>
     constexpr auto
-    operator<(const _Tp& __lhs, const optional<_Tp>& __rhs)
-    -> __optional_relop_t<decltype(declval<_Tp>() < declval<_Tp>())>
+    operator<(const _Up& __lhs, const optional<_Tp>& __rhs)
+    -> __optional_relop_t<decltype(declval<_Up>() < declval<_Tp>())>
     { return __rhs && __lhs < *__rhs; }
 
-  template<typename _Tp>
+  template<typename _Tp, typename _Up>
     constexpr auto
-    operator>(const optional<_Tp>& __lhs, const _Tp& __rhs)
-    -> __optional_relop_t<decltype(declval<_Tp>() > declval<_Tp>())>
+    operator>(const optional<_Tp>& __lhs, const _Up& __rhs)
+    -> __optional_relop_t<decltype(declval<_Tp>() > declval<_Up>())>
     { return __lhs && *__lhs > __rhs; }
 
-  template<typename _Tp>
+  template<typename _Tp, typename _Up>
     constexpr auto
-    operator>(const _Tp& __lhs, const optional<_Tp>& __rhs)
-    -> __optional_relop_t<decltype(declval<_Tp>() > declval<_Tp>())>
+    operator>(const _Up& __lhs, const optional<_Tp>& __rhs)
+    -> __optional_relop_t<decltype(declval<_Up>() > declval<_Tp>())>
     { return !__rhs || __lhs > *__rhs; }
 
-  template<typename _Tp>
+  template<typename _Tp, typename _Up>
     constexpr auto
-    operator<=(const optional<_Tp>& __lhs, const _Tp& __rhs)
-    -> __optional_relop_t<decltype(declval<_Tp>() <= declval<_Tp>())>
+    operator<=(const optional<_Tp>& __lhs, const _Up& __rhs)
+    -> __optional_relop_t<decltype(declval<_Tp>() <= declval<_Up>())>
     { return !__lhs || *__lhs <= __rhs; }
 
-  template<typename _Tp>
+  template<typename _Tp, typename _Up>
     constexpr auto
-    operator<=(const _Tp& __lhs, const optional<_Tp>& __rhs)
-    -> __optional_relop_t<decltype(declval<_Tp>() <= declval<_Tp>())>
+    operator<=(const _Up& __lhs, const optional<_Tp>& __rhs)
+    -> __optional_relop_t<decltype(declval<_Up>() <= declval<_Tp>())>
     { return __rhs && __lhs <= *__rhs; }
 
-  template<typename _Tp>
+  template<typename _Tp, typename _Up>
     constexpr auto
-    operator>=(const optional<_Tp>& __lhs, const _Tp& __rhs)
-    -> __optional_relop_t<decltype(declval<_Tp>() >= declval<_Tp>())>
+    operator>=(const optional<_Tp>& __lhs, const _Up& __rhs)
+    -> __optional_relop_t<decltype(declval<_Tp>() >= declval<_Up>())>
     { return __lhs && *__lhs >= __rhs; }
 
-  template<typename _Tp>
+  template<typename _Tp, typename _Up>
     constexpr auto
-    operator>=(const _Tp& __lhs, const optional<_Tp>& __rhs)
-    -> __optional_relop_t<decltype(declval<_Tp>() >= declval<_Tp>())>
+    operator>=(const _Up& __lhs, const optional<_Tp>& __rhs)
+    -> __optional_relop_t<decltype(declval<_Up>() >= declval<_Tp>())>
     { return !__rhs || __lhs >= *__rhs; }
 
   // Swap and creation functions.
diff --git a/libstdc++-v3/testsuite/20_util/optional/relops/7.cc b/libstdc++-v3/testsuite/20_util/optional/relops/7.cc
new file mode 100644
index 0000000..04b4cda
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/optional/relops/7.cc
@@ -0,0 +1,72 @@
+// { dg-options "-std=gnu++17" }
+// { dg-do run }
+
+// Copyright (C) 2017 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#include <optional>
+#include <testsuite_hooks.h>
+#include <string>
+
+int main()
+{
+  std::optional<int> o = 42;
+  std::optional<const int> o2 = 666;
+  VERIFY(o == 42);
+  VERIFY(o != 43);
+  VERIFY(o < 43);
+  VERIFY(o > 41);
+  VERIFY(o <= 43);
+  VERIFY(o >= 41);
+  VERIFY(o2 == 666);
+  VERIFY(o2 != 667);
+  VERIFY(o2 < 667);
+  VERIFY(o2 > 665);
+  VERIFY(o2 <= 667);
+  VERIFY(o2 >= 665);
+  VERIFY(42 == o);
+  VERIFY(43 != o);
+  VERIFY(41< o);
+  VERIFY(43 > o);
+  VERIFY(41 <= o);
+  VERIFY(43 >= o);
+  VERIFY(666 == o2);
+  VERIFY(667 != o2);
+  VERIFY(665 < o2);
+  VERIFY(667 > o2);
+  VERIFY(665 <= o2);
+  VERIFY(667 >= o2);
+  std::optional<std::string> os = "jones";
+  VERIFY(os == "jones");
+  VERIFY(os != "bones");
+  VERIFY(os < "kones");
+  VERIFY(os > "hones");
+  VERIFY(os <= "kones");
+  VERIFY(os >= "hones");
+  VERIFY("jones" == os);
+  VERIFY("bones" != os);
+  VERIFY("hones" < os);
+  VERIFY("kones" > os);
+  VERIFY("hones" <= os);
+  VERIFY("kones" >= os);
+  std::optional<int> oi = 42;
+  std::optional<long int> ol = 666;
+  VERIFY(!(oi == ol));
+  VERIFY(!(ol == oi));
+  VERIFY(oi != ol);
+  VERIFY(ol != oi);
+}