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[libc++] Implement P2447 "std::span convertible from std::initializer_list".
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-5
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‎libcxx/include/module.modulemap‎

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@@ -735,6 +735,7 @@ module std [system] {
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}
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module span {
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header "span"
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export initializer_list
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export ranges.__ranges.enable_borrowed_range
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export version
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}

‎libcxx/include/span‎

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@@ -68,6 +68,7 @@ public:
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constexpr span(const array<value_type, N>& arr) noexcept;
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template<class R>
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constexpr explicit(extent != dynamic_extent) span(R&& r);
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constexpr explicit(extent != dynamic_extent) span(initializer_list<value_type> il) noexcept;
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constexpr span(const span& other) noexcept = default;
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template <class OtherElementType, size_t OtherExtent>
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constexpr explicit(Extent != dynamic_extent) span(const span<OtherElementType, OtherExtent>& s) noexcept;
@@ -138,6 +139,7 @@ template<class R>
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#include <__ranges/size.h>
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#include <array> // for array
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#include <cstddef> // for byte
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#include <initializer_list>
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#include <iterator> // for iterators
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#include <limits>
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#include <type_traits> // for remove_cv, etc
@@ -256,6 +258,10 @@ public:
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}
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#endif
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constexpr explicit span(initializer_list<value_type> __il) requires is_const_v<element_type> : __data(__il.begin()) {
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_LIBCPP_ASSERT(__il.size() == _Extent, "size mismatch in span's constructor (initializer list)");
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}
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template <class _OtherElementType>
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_LIBCPP_INLINE_VISIBILITY
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constexpr span(const span<_OtherElementType, _Extent>& __other,
@@ -440,6 +446,9 @@ public:
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constexpr span(_Range&& __r) : __data{ranges::data(__r)}, __size{ranges::size(__r)} {}
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# endif
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constexpr span(initializer_list<value_type> __il) requires is_const_v<element_type>
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: __data(__il.begin()), __size(__il.size()) {}
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template <class _OtherElementType, size_t _OtherExtent>
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_LIBCPP_INLINE_VISIBILITY
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constexpr span(const span<_OtherElementType, _OtherExtent>& __other,

‎libcxx/test/std/containers/views/span.cons/array.pass.cpp‎

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@@ -94,9 +94,7 @@ constexpr bool testSpan()
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assert(s4.data() == val && s4.size() == 2);
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std::span<const int> s5 = {{1,2}};
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std::span<const int, 2> s6 = {{1,2}};
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assert(s5.size() == 2); // and it dangles
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assert(s6.size() == 2); // and it dangles
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return true;
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}

‎libcxx/test/std/containers/views/span.cons/initializer_list.pass.cpp‎

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@@ -28,9 +28,9 @@ constexpr int countn(std::span<const Sink, N> sp) {
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constexpr bool test() {
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Sink a[10];
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assert(count({a}) == 10);
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assert(count({a, a+10}) == 10);
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assert(countn<10>({a}) == 10);
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assert(count({a}) == 1);
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assert(count({a, a+10}) == 2);
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assert(count({a, a+1, a+2}) == 3);
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return true;
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}
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