Add pre-C++11 is_constructible wrappers for 3 arguments
Summary:
After rL319736 for D28253 (which fixes PR28929), gcc cannot compile
<memory> anymore in pre-C+11 modes, complaining:
In file included from /usr/include/c++/v1/memory:648:0,
from test.cpp:1:
/usr/include/c++/v1/memory: In static member function 'static std::__1::shared_ptr<_Tp> std::__1::shared_ptr<_Tp>::make_shared(_A0&, _A1&, _A2&)':
/usr/include/c++/v1/memory:4365:5: error: wrong number of template arguments (4, should be at least 1)
static_assert((is_constructible<_Tp, _A0, _A1, _A2>::value), "Can't construct object in make_shared" );
^
In file included from /usr/include/c++/v1/memory:649:0,
from test.cpp:1:
/usr/include/c++/v1/type_traits:3198:29: note: provided for 'template<class _Tp, class _A0, class _A1> struct std::__1::is_constructible'
struct _LIBCPP_TEMPLATE_VIS is_constructible
^~~~~~~~~~~~~~~~
In file included from /usr/include/c++/v1/memory:648:0,
from test.cpp:1:
/usr/include/c++/v1/memory:4365:5: error: template argument 1 is invalid
static_assert((is_constructible<_Tp, _A0, _A1, _A2>::value), "Can't construct object in make_shared" );
^
/usr/include/c++/v1/memory: In static member function 'static std::__1::shared_ptr<_Tp> std::__1::shared_ptr<_Tp>::allocate_shared(const _Alloc&, _A0&, _A1&, _A2&)':
/usr/include/c++/v1/memory:4444:5: error: wrong number of template arguments (4, should be at least 1)
static_assert((is_constructible<_Tp, _A0, _A1, _A2>::value), "Can't construct object in allocate_shared" );
^
In file included from /usr/include/c++/v1/memory:649:0,
from test.cpp:1:
/usr/include/c++/v1/type_traits:3198:29: note: provided for 'template<class _Tp, class _A0, class _A1> struct std::__1::is_constructible'
struct _LIBCPP_TEMPLATE_VIS is_constructible
^~~~~~~~~~~~~~~~
In file included from /usr/include/c++/v1/memory:648:0,
from test.cpp:1:
/usr/include/c++/v1/memory:4444:5: error: template argument 1 is invalid
static_assert((is_constructible<_Tp, _A0, _A1, _A2>::value), "Can't construct object in allocate_shared" );
^
This is also reported in https://bugs.freebsd.org/224946 (FreeBSD is
apparently one of the very few projects that regularly builds
programs against libc++ with gcc).
The reason is that the static assertions are invoking
is_constructible with three arguments, while gcc does not have the
built-in is_constructible feature, and the pre-C++11 is_constructible
wrappers in <type_traits> only provide up to two arguments.
I have added additional wrappers for three arguments, modified the
is_constructible entry point to take three arguments instead, and
added a simple test to is_constructible.pass.cpp.
Reviewers: EricWF, mclow.lists
Reviewed By: EricWF
Subscribers: krytarowski, cfe-commits, emaste
Differential Revision: https://reviews.llvm.org/D41805
This should allow gcc to compile the libc++ 6.0.0 <memory> header
without problems, in pre-C++11 mode.
Reported by: jbeich
PR: 224946
687571a78b