diff options
| author | Eric Fiselier <eric@efcs.ca> | 2019-07-03 19:21:40 +0000 |
|---|---|---|
| committer | Eric Fiselier <eric@efcs.ca> | 2019-07-03 19:21:40 +0000 |
| commit | 78af2bfb2f1e38c398b3dfdd9927a2fb2652f3c8 (patch) | |
| tree | 3864ecbd71828e5a9b4ca89612fb6cd82fbac38a | |
| parent | ba4d4df3ab1382dd07d31fa50d5ab72ba11e76b8 (diff) | |
Fix tuple's conditionally explicit constructors for very weird user
types.
It seems some people like to write types that can explicitly convert
to anything, but cannot be used to explicitly construct anything.
This patch makes tuple tolerate such types, as is required
by the standard.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@365074 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | include/tuple | 11 | ||||
| -rw-r--r-- | test/std/utilities/tuple/tuple.tuple/tuple.cnstr/convert_move.pass.cpp | 14 |
2 files changed, 24 insertions, 1 deletions
diff --git a/include/tuple b/include/tuple index c192d100e..de30e86c7 100644 --- a/include/tuple +++ b/include/tuple @@ -521,6 +521,13 @@ class _LIBCPP_TEMPLATE_VIS tuple template <class ..._Args> static constexpr bool __enable_implicit() { return + __tuple_constructible< + tuple<_Args...>, + typename __make_tuple_types<tuple, + sizeof...(_Args) < sizeof...(_Tp) ? + sizeof...(_Args) : + sizeof...(_Tp)>::type + >::value && __tuple_convertible< tuple<_Args...>, typename __make_tuple_types<tuple, @@ -547,7 +554,8 @@ class _LIBCPP_TEMPLATE_VIS tuple { template <class _Tuple> static constexpr bool __enable_implicit() { - return __tuple_convertible<_Tuple, tuple>::value; + return __tuple_constructible<_Tuple, tuple>::value + && __tuple_convertible<_Tuple, tuple>::value; } template <class _Tuple> @@ -577,6 +585,7 @@ class _LIBCPP_TEMPLATE_VIS tuple template <class _Tuple> static constexpr bool __enable_implicit() { return _And< + __tuple_constructible<_Tuple, tuple>, __tuple_convertible<_Tuple, tuple>, _PreferTupleLikeConstructor<_Tuple> >::value; diff --git a/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/convert_move.pass.cpp b/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/convert_move.pass.cpp index f34320144..2c24f786a 100644 --- a/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/convert_move.pass.cpp +++ b/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/convert_move.pass.cpp @@ -46,6 +46,20 @@ struct D explicit D(int i) : B(i) {} }; +struct BonkersBananas { + template <class T> + operator T() &&; + template <class T, class = void> + explicit operator T() && = delete; +}; + +void test_bonkers_bananas_conversion() { + using ReturnType = std::tuple<int, int>; + static_assert(std::is_convertible<BonkersBananas, ReturnType>(), ""); + static_assert(!std::is_constructible<ReturnType, BonkersBananas>(), ""); + +} + int main(int, char**) { { |