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author | Michael Park <mcypark@gmail.com> | 2017-06-19 08:25:57 +0000 |
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committer | Michael Park <mcypark@gmail.com> | 2017-06-19 08:25:57 +0000 |
commit | b47a9bc6c40a06aeaec76262e056b8bd1a5203ec (patch) | |
tree | 509dbed2f149ff324e848c2d2f86681091302a04 | |
parent | 7db4f7b42648a33050ff1a8c85098080ebe55d34 (diff) |
Add a missing SFINAE condition to the `variant`'s converting constructor.
Remarks: This function shall not participate in overload resolution unless
`is_same_v<decay_t<T>, variant>` is false, unless `decay_t<T>` is
neither a specialization of `in_place_type_t` nor a specialization of
`in_place_index_t`, unless `is_constructible_v<Tj, T>` is true, and
unless the expression `FUN(std::forward<T>(t))` (with `FUN` being the
above-mentioned set of imaginary functions) is well formed.
Depends on D34111.
Reviewers: EricWF, K-ballo
Reviewed By: EricWF
Subscribers: fhahn
Differential Revision: https://reviews.llvm.org/D34112
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@305668 91177308-0d34-0410-b5e6-96231b3b80d8
-rw-r--r-- | include/variant | 2 | ||||
-rw-r--r-- | test/std/utilities/variant/variant.variant/variant.ctor/T.pass.cpp | 14 |
2 files changed, 16 insertions, 0 deletions
diff --git a/include/variant b/include/variant index 8711ef6eb..f8d3e28ba 100644 --- a/include/variant +++ b/include/variant @@ -1116,6 +1116,8 @@ public: template < class _Arg, enable_if_t<!is_same_v<decay_t<_Arg>, variant>, int> = 0, + enable_if_t<!__is_inplace_type<decay_t<_Arg>>::value, int> = 0, + enable_if_t<!__is_inplace_index<decay_t<_Arg>>::value, int> = 0, class _Tp = __variant_detail::__best_match_t<_Arg, _Types...>, size_t _Ip = __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value, diff --git a/test/std/utilities/variant/variant.variant/variant.ctor/T.pass.cpp b/test/std/utilities/variant/variant.variant/variant.ctor/T.pass.cpp index d33ea0bd3..3f7cd4f0b 100644 --- a/test/std/utilities/variant/variant.variant/variant.ctor/T.pass.cpp +++ b/test/std/utilities/variant/variant.variant/variant.ctor/T.pass.cpp @@ -37,6 +37,9 @@ struct NoThrowT { NoThrowT(int) noexcept(true) {} }; +struct AnyConstructible { template <typename T> AnyConstructible(T&&) {} }; +struct NoConstructible { NoConstructible() = delete; }; + void test_T_ctor_noexcept() { { using V = std::variant<Dummy, NoThrowT>; @@ -62,6 +65,17 @@ void test_T_ctor_sfinae() { static_assert(!std::is_constructible<V, int>::value, "no matching constructor"); } + { + using V = std::variant<AnyConstructible, NoConstructible>; + static_assert( + !std::is_constructible<V, std::in_place_type_t<NoConstructible>>::value, + "no matching constructor"); + static_assert(!std::is_constructible<V, std::in_place_index_t<1>>::value, + "no matching constructor"); + } + + + #if !defined(TEST_VARIANT_HAS_NO_REFERENCES) { using V = std::variant<int, int &&>; |