Reland [libc++] [P0325] Implement to_array from LFTS with updates.
Fixed expected errors and notes.
Summary:
This patch implements https://wg21.link/P0325.
Reviewers: EricWF, mclow.lists, ldionne, lichray
Reviewed By: ldionne, lichray
Subscribers: lichray, dexonsmith, zoecarver, christof, ldionne, libcxx-commits
Tags: #libc
Differential Revision: https://reviews.llvm.org/D69882
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: e93e58c6c40a365bc9275dd8a8242598343cc835
diff --git a/docs/FeatureTestMacroTable.rst b/docs/FeatureTestMacroTable.rst
index 3dd00fa..a02e727 100644
--- a/docs/FeatureTestMacroTable.rst
+++ b/docs/FeatureTestMacroTable.rst
@@ -199,6 +199,8 @@
``__cpp_lib_ranges`` *unimplemented*
------------------------------------------------- -----------------
``__cpp_lib_three_way_comparison`` *unimplemented*
+ ------------------------------------------------- -----------------
+ ``__cpp_lib_to_array`` ``201907L``
================================================= =================
diff --git a/include/array b/include/array
index 88e9d57..64ca68d 100644
--- a/include/array
+++ b/include/array
@@ -479,6 +479,47 @@
#endif // !_LIBCPP_CXX03_LANG
+#if _LIBCPP_STD_VER > 17
+
+template <typename _Tp, size_t _Size, size_t... _Index>
+_LIBCPP_INLINE_VISIBILITY constexpr array<remove_cv_t<_Tp>, _Size>
+__to_array_lvalue_impl(_Tp (&__arr)[_Size], index_sequence<_Index...>) {
+ return {{__arr[_Index]...}};
+}
+
+template <typename _Tp, size_t _Size, size_t... _Index>
+_LIBCPP_INLINE_VISIBILITY constexpr array<remove_cv_t<_Tp>, _Size>
+__to_array_rvalue_impl(_Tp(&&__arr)[_Size], index_sequence<_Index...>) {
+ return {{_VSTD::move(__arr[_Index])...}};
+}
+
+template <typename _Tp, size_t _Size>
+_LIBCPP_INLINE_VISIBILITY constexpr array<remove_cv_t<_Tp>, _Size>
+to_array(_Tp (&__arr)[_Size]) noexcept(is_nothrow_constructible_v<_Tp, _Tp&>) {
+ static_assert(
+ !is_array_v<_Tp>,
+ "[array.creation]/1: to_array does not accept multidimensional arrays.");
+ static_assert(
+ is_constructible_v<_Tp, _Tp&>,
+ "[array.creation]/1: to_array requires copy constructible elements.");
+ return __to_array_lvalue_impl(__arr, make_index_sequence<_Size>());
+}
+
+template <typename _Tp, size_t _Size>
+_LIBCPP_INLINE_VISIBILITY constexpr array<remove_cv_t<_Tp>, _Size>
+to_array(_Tp(&&__arr)[_Size]) noexcept(is_nothrow_move_constructible_v<_Tp>) {
+ static_assert(
+ !is_array_v<_Tp>,
+ "[array.creation]/4: to_array does not accept multidimensional arrays.");
+ static_assert(
+ is_move_constructible_v<_Tp>,
+ "[array.creation]/4: to_array requires move constructible elements.");
+ return __to_array_rvalue_impl(_VSTD::move(__arr),
+ make_index_sequence<_Size>());
+}
+
+#endif // _LIBCPP_STD_VER > 17
+
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP_ARRAY
diff --git a/include/version b/include/version
index 2abc71e..2d9a2b3 100644
--- a/include/version
+++ b/include/version
@@ -101,6 +101,7 @@
__cpp_lib_string_udls 201304L <string>
__cpp_lib_string_view 201606L <string> <string_view>
__cpp_lib_three_way_comparison 201711L <compare>
+__cpp_lib_to_array 201907L <array>
__cpp_lib_to_chars 201611L <utility>
__cpp_lib_transformation_trait_aliases 201304L <type_traits>
__cpp_lib_transparent_operators 201510L <functional>
@@ -233,6 +234,7 @@
# endif
// # define __cpp_lib_list_remove_return_type 201806L
// # define __cpp_lib_ranges 201811L
+# define __cpp_lib_to_array 201907L
// # define __cpp_lib_three_way_comparison 201711L
#endif
diff --git a/test/std/containers/sequences/array/array.creation/to_array.fail.cpp b/test/std/containers/sequences/array/array.creation/to_array.fail.cpp
new file mode 100644
index 0000000..7d8e134
--- /dev/null
+++ b/test/std/containers/sequences/array/array.creation/to_array.fail.cpp
@@ -0,0 +1,42 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// <array>
+// UNSUPPORTED: c++98, c++03, c++11, c++14, c++17
+
+#include <array>
+
+#include "test_macros.h"
+#include "MoveOnly.h"
+
+int main(int, char**) {
+ {
+ char source[3][6] = {"hi", "world"};
+ // expected-error@array:* {{to_array does not accept multidimensional arrays}}
+ // expected-error@array:* {{to_array requires copy constructible elements}}
+ // expected-error@array:* 3 {{cannot initialize}}
+ // expected-error@array:* {{suggest braces}}
+ std::to_array(source); // expected-note {{requested here}}
+ }
+
+ {
+ MoveOnly mo[] = {MoveOnly{3}};
+ // expected-error@array:* {{to_array requires copy constructible elements}}
+ // expected-error@array:* {{calling a private constructor}}
+ std::to_array(mo); // expected-note {{requested here}}
+ }
+
+ {
+ const MoveOnly cmo[] = {MoveOnly{3}};
+ // expected-error@array:* {{to_array requires move constructible elements}}
+ // expected-error@array:* {{calling a private constructor}}
+ std::to_array(std::move(cmo)); // expected-note {{requested here}}
+ }
+
+ return 0;
+}
diff --git a/test/std/containers/sequences/array/array.creation/to_array.pass.cpp b/test/std/containers/sequences/array/array.creation/to_array.pass.cpp
new file mode 100644
index 0000000..d5df96a
--- /dev/null
+++ b/test/std/containers/sequences/array/array.creation/to_array.pass.cpp
@@ -0,0 +1,122 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// <array>
+// UNSUPPORTED: c++98, c++03, c++11, c++14, c++17
+
+// template <typename T, size_t Size>
+// constexpr auto to_array(T (&arr)[Size])
+// -> array<remove_cv_t<T>, Size>;
+
+// template <typename T, size_t Size>
+// constexpr auto to_array(T (&&arr)[Size])
+// -> array<remove_cv_t<T>, Size>;
+
+#include <array>
+#include <cassert>
+
+#include "test_macros.h"
+#include "MoveOnly.h"
+
+int main(int, char**) {
+ // Test deduced type.
+ {
+ auto arr = std::to_array({1, 2, 3});
+ ASSERT_SAME_TYPE(decltype(arr), std::array<int, 3>);
+ assert(arr[0] == 1);
+ assert(arr[1] == 2);
+ assert(arr[2] == 3);
+ }
+
+ {
+ const long l1 = 42;
+ auto arr = std::to_array({1L, 4L, 9L, l1});
+ ASSERT_SAME_TYPE(decltype(arr)::value_type, long);
+ static_assert(arr.size() == 4, "");
+ assert(arr[0] == 1);
+ assert(arr[1] == 4);
+ assert(arr[2] == 9);
+ assert(arr[3] == l1);
+ }
+
+ {
+ auto arr = std::to_array("meow");
+ ASSERT_SAME_TYPE(decltype(arr), std::array<char, 5>);
+ assert(arr[0] == 'm');
+ assert(arr[1] == 'e');
+ assert(arr[2] == 'o');
+ assert(arr[3] == 'w');
+ assert(arr[4] == '\0');
+ }
+
+ {
+ double source[3] = {4.0, 5.0, 6.0};
+ auto arr = std::to_array(source);
+ ASSERT_SAME_TYPE(decltype(arr), std::array<double, 3>);
+ assert(arr[0] == 4.0);
+ assert(arr[1] == 5.0);
+ assert(arr[2] == 6.0);
+ }
+
+ {
+ double source[3] = {4.0, 5.0, 6.0};
+ auto arr = std::to_array(std::move(source));
+ ASSERT_SAME_TYPE(decltype(arr), std::array<double, 3>);
+ assert(arr[0] == 4.0);
+ assert(arr[1] == 5.0);
+ assert(arr[2] == 6.0);
+ }
+
+ {
+ MoveOnly source[] = {MoveOnly{0}, MoveOnly{1}, MoveOnly{2}};
+
+ auto arr = std::to_array(std::move(source));
+ ASSERT_SAME_TYPE(decltype(arr), std::array<MoveOnly, 3>);
+ for (int i = 0; i < 3; ++i)
+ assert(arr[i].get() == i && source[i].get() == 0);
+ }
+
+ // Test C99 compound literal.
+ {
+ auto arr = std::to_array((int[]){3, 4});
+ ASSERT_SAME_TYPE(decltype(arr), std::array<int, 2>);
+ assert(arr[0] == 3);
+ assert(arr[1] == 4);
+ }
+
+ // Test explicit type.
+ {
+ auto arr = std::to_array<long>({1, 2, 3});
+ ASSERT_SAME_TYPE(decltype(arr), std::array<long, 3>);
+ assert(arr[0] == 1);
+ assert(arr[1] == 2);
+ assert(arr[2] == 3);
+ }
+
+ {
+ struct A {
+ int a;
+ double b;
+ };
+
+ auto arr = std::to_array<A>({{3, .1}});
+ ASSERT_SAME_TYPE(decltype(arr), std::array<A, 1>);
+ assert(arr[0].a == 3);
+ assert(arr[0].b == .1);
+ }
+
+ // Test constexpr.
+ {
+ constexpr std::array<int, 3> arr = std::to_array({1, 2, 3});
+ static_assert(arr[0] == 1);
+ static_assert(arr[1] == 2);
+ static_assert(arr[2] == 3);
+ }
+
+ return 0;
+}
diff --git a/test/std/language.support/support.limits/support.limits.general/array.version.pass.cpp b/test/std/language.support/support.limits/support.limits.general/array.version.pass.cpp
index d590f98..1524589 100644
--- a/test/std/language.support/support.limits/support.limits.general/array.version.pass.cpp
+++ b/test/std/language.support/support.limits/support.limits.general/array.version.pass.cpp
@@ -17,6 +17,7 @@
__cpp_lib_array_constexpr 201603L [C++17]
__cpp_lib_constexpr_misc 201811L [C++2a]
__cpp_lib_nonmember_container_access 201411L [C++17]
+ __cpp_lib_to_array 201907L [C++2a]
*/
#include <array>
@@ -36,6 +37,10 @@
# error "__cpp_lib_nonmember_container_access should not be defined before c++17"
# endif
+# ifdef __cpp_lib_to_array
+# error "__cpp_lib_to_array should not be defined before c++2a"
+# endif
+
#elif TEST_STD_VER == 14
# ifdef __cpp_lib_array_constexpr
@@ -50,6 +55,10 @@
# error "__cpp_lib_nonmember_container_access should not be defined before c++17"
# endif
+# ifdef __cpp_lib_to_array
+# error "__cpp_lib_to_array should not be defined before c++2a"
+# endif
+
#elif TEST_STD_VER == 17
# ifndef __cpp_lib_array_constexpr
@@ -70,6 +79,10 @@
# error "__cpp_lib_nonmember_container_access should have the value 201411L in c++17"
# endif
+# ifdef __cpp_lib_to_array
+# error "__cpp_lib_to_array should not be defined before c++2a"
+# endif
+
#elif TEST_STD_VER > 17
# ifndef __cpp_lib_array_constexpr
@@ -99,6 +112,13 @@
# error "__cpp_lib_nonmember_container_access should have the value 201411L in c++2a"
# endif
+# ifndef __cpp_lib_to_array
+# error "__cpp_lib_to_array should be defined in c++2a"
+# endif
+# if __cpp_lib_to_array != 201907L
+# error "__cpp_lib_to_array should have the value 201907L in c++2a"
+# endif
+
#endif // TEST_STD_VER > 17
int main(int, char**) { return 0; }
diff --git a/test/std/language.support/support.limits/support.limits.general/version.version.pass.cpp b/test/std/language.support/support.limits/support.limits.general/version.version.pass.cpp
index e721b73..979d7db 100644
--- a/test/std/language.support/support.limits/support.limits.general/version.version.pass.cpp
+++ b/test/std/language.support/support.limits/support.limits.general/version.version.pass.cpp
@@ -88,6 +88,7 @@
__cpp_lib_string_udls 201304L [C++14]
__cpp_lib_string_view 201606L [C++17]
__cpp_lib_three_way_comparison 201711L [C++2a]
+ __cpp_lib_to_array 201907L [C++2a]
__cpp_lib_to_chars 201611L [C++17]
__cpp_lib_transformation_trait_aliases 201304L [C++14]
__cpp_lib_transparent_operators 201210L [C++14]
@@ -402,6 +403,10 @@
# error "__cpp_lib_three_way_comparison should not be defined before c++2a"
# endif
+# ifdef __cpp_lib_to_array
+# error "__cpp_lib_to_array should not be defined before c++2a"
+# endif
+
# ifdef __cpp_lib_to_chars
# error "__cpp_lib_to_chars should not be defined before c++17"
# endif
@@ -794,6 +799,10 @@
# error "__cpp_lib_three_way_comparison should not be defined before c++2a"
# endif
+# ifdef __cpp_lib_to_array
+# error "__cpp_lib_to_array should not be defined before c++2a"
+# endif
+
# ifdef __cpp_lib_to_chars
# error "__cpp_lib_to_chars should not be defined before c++17"
# endif
@@ -1390,6 +1399,10 @@
# error "__cpp_lib_three_way_comparison should not be defined before c++2a"
# endif
+# ifdef __cpp_lib_to_array
+# error "__cpp_lib_to_array should not be defined before c++2a"
+# endif
+
# if !defined(_LIBCPP_VERSION)
# ifndef __cpp_lib_to_chars
# error "__cpp_lib_to_chars should be defined in c++17"
@@ -2136,6 +2149,13 @@
# endif
# endif
+# ifndef __cpp_lib_to_array
+# error "__cpp_lib_to_array should be defined in c++2a"
+# endif
+# if __cpp_lib_to_array != 201907L
+# error "__cpp_lib_to_array should have the value 201907L in c++2a"
+# endif
+
# if !defined(_LIBCPP_VERSION)
# ifndef __cpp_lib_to_chars
# error "__cpp_lib_to_chars should be defined in c++2a"
diff --git a/utils/generate_feature_test_macro_components.py b/utils/generate_feature_test_macro_components.py
index a6191a5..faec065 100755
--- a/utils/generate_feature_test_macro_components.py
+++ b/utils/generate_feature_test_macro_components.py
@@ -586,6 +586,12 @@
},
"headers": ["bit"],
},
+ {"name": "__cpp_lib_to_array",
+ "values": {
+ "c++2a": 201907L,
+ },
+ "headers": ["array"],
+ },
]], key=lambda tc: tc["name"])
def get_std_dialects():
diff --git a/www/cxx2a_status.html b/www/cxx2a_status.html
index 73a7430..a8f6c2f 100644
--- a/www/cxx2a_status.html
+++ b/www/cxx2a_status.html
@@ -157,7 +157,7 @@
<tr><td><a href="https://wg21.link/P1464R1">P1464R1</a></td><td>LWG</td><td>Mandating the Standard Library: Clause 22 - Iterators library</td><td>Kona</td><td>Complete</td><td>9.0</td></tr>
<tr><td></td><td></td><td></td><td></td><td></td><td></td></tr>
- <tr><td><a href="https://wg21.link/P0325">P0325</a></td><td>LWG</td><td>to_array from LFTS with updates</td><td>Cologne</td><td></td><td></td></tr>
+ <tr><td><a href="https://wg21.link/P0325">P0325</a></td><td>LWG</td><td>to_array from LFTS with updates</td><td>Cologne</td><td>Complete</td><td>10.0</td></tr>
<tr><td><a href="https://wg21.link/P0408">P0408</a></td><td>LWG</td><td>Efficient Access to basic_stringbuf ’s Buffer</td><td>Cologne</td><td></td><td></td></tr>
<tr><td><a href="https://wg21.link/P0466">P0466</a></td><td>LWG</td><td>Layout-compatibility and Pointer-interconvertibility Traits</td><td>Cologne</td><td></td><td></td></tr>
<tr><td><a href="https://wg21.link/P0553">P0553</a></td><td>LWG</td><td>Bit operations</td><td>Cologne</td><td>Complete</td><td>9.0</td></tr>