[committed] libstdc++: Prevent unwanted ADL in std::to_array [PR111512]
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Commit Message
This is the fix for the release branches, where std::to_array is
implemented differently.
Tested x86_64-linux. Pushed to gcc-13 and gcc-12. Will push to gcc-11
after testing.
-- >8 --
Qualify the calls to the __to_array helper to prevent ADL, so we don't
try to complete associated classes.
libstdc++-v3/ChangeLog:
PR libstdc++/111511
PR c++/111512
* include/std/array (to_array): Qualify calls to __to_array.
* testsuite/23_containers/array/creation/111512.cc: New test.
(cherry picked from commit 77cf3773021b0a20d89623e09d620747a05588ec)
---
libstdc++-v3/include/std/array | 4 +--
.../23_containers/array/creation/111512.cc | 25 +++++++++++++++++++
2 files changed, 27 insertions(+), 2 deletions(-)
create mode 100644 libstdc++-v3/testsuite/23_containers/array/creation/111512.cc
@@ -436,7 +436,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
static_assert(!is_array_v<_Tp>);
static_assert(is_constructible_v<_Tp, _Tp&>);
if constexpr (is_constructible_v<_Tp, _Tp&>)
- return __to_array(__a, make_index_sequence<_Nm>{});
+ return std::__to_array(__a, make_index_sequence<_Nm>{});
__builtin_unreachable(); // FIXME: see PR c++/91388
}
@@ -449,7 +449,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
static_assert(!is_array_v<_Tp>);
static_assert(is_move_constructible_v<_Tp>);
if constexpr (is_move_constructible_v<_Tp>)
- return __to_array<1>(__a, make_index_sequence<_Nm>{});
+ return std::__to_array<1>(__a, make_index_sequence<_Nm>{});
__builtin_unreachable(); // FIXME: see PR c++/91388
}
#endif // C++20
new file mode 100644
@@ -0,0 +1,25 @@
+// { dg-options "-std=gnu++20" }
+// { dg-do compile { target c++20 } }
+
+// Bug libstdc++/111511 - Incorrect ADL in std::to_array in GCC 11/12/13
+// Bug c++/111512 - GCC's __builtin_memcpy can trigger ADL
+
+#include <array>
+#include <utility>
+
+struct incomplete;
+
+template<class T>
+struct holder {
+ T t; // { dg-bogus "'holder<T>::t' has incomplete type" }
+};
+
+// A complete type that cannot be used as an associated type for ADL.
+using adl_bomb = holder<incomplete>*;
+
+int main()
+{
+ adl_bomb a[1]{};
+ (void) std::to_array(a);
+ (void) std::to_array(std::move(a));
+}