diff --git a/libcxx/include/span b/libcxx/include/span
--- a/libcxx/include/span
+++ b/libcxx/include/span
@@ -212,8 +212,16 @@
{ (void)__l; _LIBCPP_ASSERT(_Extent == distance(__f, __l), "size mismatch in span's constructor (ptr, ptr)"); }
_LIBCPP_INLINE_VISIBILITY constexpr span(element_type (&__arr)[_Extent]) noexcept : __data{__arr} {}
- _LIBCPP_INLINE_VISIBILITY constexpr span( array<value_type, _Extent>& __arr) noexcept : __data{__arr.data()} {}
- _LIBCPP_INLINE_VISIBILITY constexpr span(const array<value_type, _Extent>& __arr) noexcept : __data{__arr.data()} {}
+
+ template <class _OtherElementType,
+ enable_if_t<is_convertible_v<_OtherElementType(*)[], element_type (*)[]>, nullptr_t> = nullptr>
+ _LIBCPP_INLINE_VISIBILITY
+ constexpr span(array<_OtherElementType, _Extent>& __arr) noexcept : __data{__arr.data()} {}
+
+ template <class _OtherElementType,
+ enable_if_t<is_convertible_v<const _OtherElementType(*)[], element_type (*)[]>, nullptr_t> = nullptr>
+ _LIBCPP_INLINE_VISIBILITY
+ constexpr span(const array<_OtherElementType, _Extent>& __arr) noexcept : __data{__arr.data()} {}
template <class _Container>
_LIBCPP_INLINE_VISIBILITY
@@ -386,13 +394,15 @@
_LIBCPP_INLINE_VISIBILITY
constexpr span(element_type (&__arr)[_Sz]) noexcept : __data{__arr}, __size{_Sz} {}
- template <size_t _Sz>
+ template <class _OtherElementType, size_t _Sz,
+ enable_if_t<is_convertible_v<_OtherElementType(*)[], element_type (*)[]>, nullptr_t> = nullptr>
_LIBCPP_INLINE_VISIBILITY
- constexpr span(array<value_type, _Sz>& __arr) noexcept : __data{__arr.data()}, __size{_Sz} {}
+ constexpr span(array<_OtherElementType, _Sz>& __arr) noexcept : __data{__arr.data()}, __size{_Sz} {}
- template <size_t _Sz>
+ template <class _OtherElementType, size_t _Sz,
+ enable_if_t<is_convertible_v<const _OtherElementType(*)[], element_type (*)[]>, nullptr_t> = nullptr>
_LIBCPP_INLINE_VISIBILITY
- constexpr span(const array<value_type, _Sz>& __arr) noexcept : __data{__arr.data()}, __size{_Sz} {}
+ constexpr span(const array<_OtherElementType, _Sz>& __arr) noexcept : __data{__arr.data()}, __size{_Sz} {}
template <class _Container>
_LIBCPP_INLINE_VISIBILITY
diff --git a/libcxx/test/std/containers/views/span.cons/stdarray.pass.cpp b/libcxx/test/std/containers/views/span.cons/stdarray.pass.cpp
--- a/libcxx/test/std/containers/views/span.cons/stdarray.pass.cpp
+++ b/libcxx/test/std/containers/views/span.cons/stdarray.pass.cpp
@@ -68,49 +68,58 @@
}
}
+template <typename T, typename U = T>
+constexpr bool testConstructorArray()
+{
+ std::array<U,2> val = { U(), U() };
+ ASSERT_NOEXCEPT(std::span<T> {val});
+ ASSERT_NOEXCEPT(std::span<T, 2>{val});
+ std::span<T> s1{val};
+ std::span<T, 2> s2{val};
+ return s1.data() == &val[0] && s1.size() == 2
+ && s2.data() == &val[0] && s2.size() == 2;
+}
-template <typename T>
-constexpr bool testConstexprSpan()
+template <typename T, typename U = T>
+constexpr bool testConstructorConstArray()
{
- constexpr std::array<T,2> val = { T(), T() };
+ const std::array<U,2> val = { U(), U() };
ASSERT_NOEXCEPT(std::span<const T> {val});
ASSERT_NOEXCEPT(std::span<const T, 2>{val});
std::span<const T> s1{val};
std::span<const T, 2> s2{val};
- return
- s1.data() == &val[0] && s1.size() == 2
- && s2.data() == &val[0] && s2.size() == 2;
+ return s1.data() == &val[0] && s1.size() == 2
+ && s2.data() == &val[0] && s2.size() == 2;
}
-
template <typename T>
-void testRuntimeSpan()
-{
- std::array<T,2> val;
- ASSERT_NOEXCEPT(std::span<T> {val});
- ASSERT_NOEXCEPT(std::span<T, 2>{val});
- std::span<T> s1{val};
- std::span<T, 2> s2{val};
- assert(s1.data() == &val[0] && s1.size() == 2);
- assert(s2.data() == &val[0] && s2.size() == 2);
+constexpr bool testConstructors() {
+ static_assert(testConstructorArray<T>(), "");
+ static_assert(testConstructorArray<const T, T>(), "");
+ static_assert(testConstructorConstArray<T>(), "");
+ static_assert(testConstructorConstArray<const T, T>(), "");
+
+ return testConstructorArray<T>()
+ && testConstructorArray<const T, T>()
+ && testConstructorConstArray<T>()
+ && testConstructorConstArray<const T, T>();
}
struct A{};
int main(int, char**)
{
- static_assert(testConstexprSpan<int>(), "");
- static_assert(testConstexprSpan<long>(), "");
- static_assert(testConstexprSpan<double>(), "");
- static_assert(testConstexprSpan<A>(), "");
+ assert(testConstructors<int>());
+ assert(testConstructors<long>());
+ assert(testConstructors<double>());
+ assert(testConstructors<A>());
- testRuntimeSpan<int>();
- testRuntimeSpan<long>();
- testRuntimeSpan<double>();
- testRuntimeSpan<std::string>();
- testRuntimeSpan<A>();
+ assert(testConstructors<int*>());
+ assert(testConstructors<int* const>());
+ assert(testConstructors<const int*>());
+ assert(testConstructors<const int* const>());
checkCV();
- return 0;
+ return 0;
}
diff --git a/libcxx/www/cxx2a_status.html b/libcxx/www/cxx2a_status.html
--- a/libcxx/www/cxx2a_status.html
+++ b/libcxx/www/cxx2a_status.html
@@ -490,7 +490,7 @@
<tr><td><a href="https://wg21.link/LWG3251">3251</a></td><td>Are <tt>std::format</tt> alignment specifiers applied to string arguments?</td><td>Prague</td><td></td></tr>
<tr><td><a href="https://wg21.link/LWG3252">3252</a></td><td>Parse locale's aware modifiers for commands are not consistent with POSIX spec</td><td>Prague</td><td></td></tr>
<tr><td><a href="https://wg21.link/LWG3254">3254</a></td><td>Strike <tt>stop_token</tt>'s <tt>operator!=</tt></td><td>Prague</td><td></td></tr>
- <tr><td><a href="https://wg21.link/LWG3255">3255</a></td><td><tt>span</tt>'s <tt>array</tt> constructor is too strict</td><td>Prague</td><td></td></tr>
+ <tr><td><a href="https://wg21.link/LWG3255">3255</a></td><td><tt>span</tt>'s <tt>array</tt> constructor is too strict</td><td>Prague</td><td>Complete</td></tr>
<tr><td><a href="https://wg21.link/LWG3260">3260</a></td><td><tt>year_month*</tt> arithmetic rejects durations convertible to years</td><td>Prague</td><td></td></tr>
<tr><td><a href="https://wg21.link/LWG3262">3262</a></td><td>Formatting of negative durations is not specified</td><td>Prague</td><td></td></tr>
<tr><td><a href="https://wg21.link/LWG3264">3264</a></td><td><tt>sized_range</tt> and <tt>ranges::size</tt> redundantly use <tt>disable_sized_range</tt></td><td>Prague</td><td></td></tr>