libstdc++: Add missing std::tuple constructor [PR114147]

I caused a regression with commit r10-908 by adding a constraint to the
non-explicit allocator-extended default constructor, but seemingly
forgot to add an explicit overload with the corresponding constraint.

libstdc++-v3/ChangeLog:

	PR libstdc++/114147
	* include/std/tuple (tuple::tuple(allocator_arg_t, const Alloc&)):
	Add missing overload of allocator-extended default constructor.
	(tuple<T1,T2>::tuple(allocator_arg_t, const Alloc&)): Likewise.
	* testsuite/20_util/tuple/cons/114147.cc: New test.

(cherry picked from commit 0a545ac7000501844670add0b3560ebdbcb123c6)

diff --git a/libstdc++-v3/include/std/tuple b/libstdc++-v3/include/std/tuple
index 63bd68fbe43f8f60c10b5ad3434dc20e50f4c170..b02b0bfbd593d6f7ab763fd053885f468c10b213 100644 (file)
--- a/libstdc++-v3/include/std/tuple
+++ b/libstdc++-v3/include/std/tuple
@@ -801,6 +801,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
        tuple(allocator_arg_t __tag, const _Alloc& __a)
        : _Inherited(__tag, __a) { }
 
+      template<typename _Alloc,
+              _ExplicitDefaultCtor<is_object<_Alloc>::value> = false>
+       _GLIBCXX20_CONSTEXPR
+       explicit
+       tuple(allocator_arg_t __tag, const _Alloc& __a)
+       : _Inherited(__tag, __a) { }
+
       template<typename _Alloc, bool _NotEmpty = (sizeof...(_Elements) >= 1),
               _ImplicitCtor<_NotEmpty, const _Elements&...> = true>
        _GLIBCXX20_CONSTEXPR
@@ -1155,6 +1162,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
        tuple(allocator_arg_t __tag, const _Alloc& __a)
        : _Inherited(__tag, __a) { }
 
+      template<typename _Alloc,
+              _ExplicitDefaultCtor<is_object<_Alloc>::value, _T1, _T2> = false>
+       _GLIBCXX20_CONSTEXPR
+       explicit
+       tuple(allocator_arg_t __tag, const _Alloc& __a)
+       : _Inherited(__tag, __a) { }
+
       template<typename _Alloc, bool _Dummy = true,
               _ImplicitCtor<_Dummy, const _T1&, const _T2&> = true>
        _GLIBCXX20_CONSTEXPR

diff --git a/libstdc++-v3/testsuite/20_util/tuple/cons/114147.cc b/libstdc++-v3/testsuite/20_util/tuple/cons/114147.cc
new file mode 100644 (file)
index 0000000..916e720
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/tuple/cons/114147.cc
@@ -0,0 +1,15 @@
+// { dg-do compile { target c++11 } }
+
+// PR libstdc++/114147
+// tuple allocator-extended ctor requires non-explicit default ctor
+
+#include <tuple>
+#include <memory>
+
+struct X { explicit X(); };
+
+std::allocator<int> a;
+std::tuple<X> t0(std::allocator_arg, a);
+std::tuple<int, X> t1(std::allocator_arg, a);
+std::tuple<X, int> t2(std::allocator_arg, a);
+std::tuple<int, X, int> t3(std::allocator_arg, a);