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
llvm-svn: 305668
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: 3f1e89380b294a1192fa4019053dc5ab3c8eacbf
diff --git a/include/variant b/include/variant
index 8711ef6..f8d3e28 100644
--- a/include/variant
+++ b/include/variant
@@ -1116,6 +1116,8 @@
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 d33ea0b..3f7cd4f 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 @@
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 @@
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 &&>;