[PATCH] libstdc++: Consistently use ::type when deriving from __and/or/not_

[Patrick Palka <ppalka@redhat.com>]

Now that these internal type traits are again class templates, it's
better to derive from the trait's ::type (which is either false_type or
true_type) instead of from the trait itself, for sake of a shallower
inheritance chain.  We usually do this but not always; this patch makes
us consistently do so.

Tested on x86_64-pc-lnux-gnu, does this look OK for trunk?  (Compile
time for join.cc decreases by about 0.5% with this, avg of 10 runs.)

libstdc++-v3/ChangeLog:

	* include/std/tuple (tuple::_UseOtherCtor): Do ::type when
	deriving from __and_, __or_ or __not_.
	* include/std/type_traits (negation): Likewise.
	(is_unsigned): Likewise.
	(__is_implicitly_default_constructible): Likewise.
	(is_trivially_destructible): Likewise.
	(__is_nt_invocable_impl): Likewise.
---
 libstdc++-v3/include/std/tuple       |  2 +-
 libstdc++-v3/include/std/type_traits | 10 +++++-----
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/libstdc++-v3/include/std/tuple b/libstdc++-v3/include/std/tuple
index ddd7c226d80..26e248431ec 100644
--- a/libstdc++-v3/include/std/tuple
+++ b/libstdc++-v3/include/std/tuple
@@ -826,7 +826,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       // then TUPLE should match tuple(UTypes&&...) instead.
       template<typename _Tuple, typename _Tp, typename _Up>
 	struct _UseOtherCtor<_Tuple, tuple<_Tp>, tuple<_Up>>
-	: __or_<is_convertible<_Tuple, _Tp>, is_constructible<_Tp, _Tuple>>
+	: __or_<is_convertible<_Tuple, _Tp>, is_constructible<_Tp, _Tuple>>::type
 	{ };
       // If TUPLE and *this each have a single element of the same type,
       // then TUPLE should match a copy/move constructor instead.
diff --git a/libstdc++-v3/include/std/type_traits b/libstdc++-v3/include/std/type_traits
index be9f2955539..c0bb1cf64e3 100644
--- a/libstdc++-v3/include/std/type_traits
+++ b/libstdc++-v3/include/std/type_traits
@@ -235,7 +235,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
   template<typename _Pp>
     struct negation
-    : __not_<_Pp>
+    : __not_<_Pp>::type
     { };
 
   /** @ingroup variable_templates
@@ -845,7 +845,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   /// is_unsigned
   template<typename _Tp>
     struct is_unsigned
-    : public __and_<is_arithmetic<_Tp>, __not_<is_signed<_Tp>>>
+    : public __and_<is_arithmetic<_Tp>, __not_<is_signed<_Tp>>>::type
     { };
 
   /// @cond undocumented
@@ -1222,7 +1222,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   template <typename _Tp>
     struct __is_implicitly_default_constructible
     : public __and_<__is_constructible_impl<_Tp>,
-		    __is_implicitly_default_constructible_safe<_Tp>>
+		    __is_implicitly_default_constructible_safe<_Tp>>::type
     { };
 
   /// is_trivially_copy_constructible
@@ -1282,7 +1282,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   template<typename _Tp>
     struct is_trivially_destructible
     : public __and_<__is_destructible_safe<_Tp>,
-		    __bool_constant<__has_trivial_destructor(_Tp)>>
+		    __bool_constant<__has_trivial_destructor(_Tp)>>::type
     {
       static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
 	"template argument must be a complete class or an unbounded array");
@@ -2975,7 +2975,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     struct __is_nt_invocable_impl<_Result, _Ret,
 				  __void_t<typename _Result::type>>
     : __or_<is_void<_Ret>,
-	    __is_nothrow_convertible<typename _Result::type, _Ret>>
+	    __is_nothrow_convertible<typename _Result::type, _Ret>>::type
     { };
   /// @endcond
 
-- 
2.37.2.490.g6c8e4ee870