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* [gcc r12-8930] libstdc++: Fix std::is_nothrow_invocable_r for uncopyable prvalues [PR91456]
@ 2022-11-24 16:36 Jonathan Wakely
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From: Jonathan Wakely @ 2022-11-24 16:36 UTC (permalink / raw)
To: gcc-cvs, libstdc++-cvs
https://gcc.gnu.org/g:db206f15f7091382cb981ade3c75f4c3e3559ab8
commit r12-8930-gdb206f15f7091382cb981ade3c75f4c3e3559ab8
Author: Jonathan Wakely <jwakely@redhat.com>
Date: Fri Sep 23 13:28:37 2022 +0100
libstdc++: Fix std::is_nothrow_invocable_r for uncopyable prvalues [PR91456]
This is the last missing piece of PR 91456.
This also removes the only use of the C++11 version of
std::is_nothrow_invocable.
libstdc++-v3/ChangeLog:
PR libstdc++/91456
* include/std/type_traits (__is_nothrow_invocable): Remove.
(__is_invocable_impl::__nothrow_type): New member type which
checks if the conversion can throw.
(__is_nt_invocable_impl): Replace class template with alias
template to __is_nt_invocable_impl::__nothrow_type.
* testsuite/20_util/is_nothrow_invocable/91456.cc: New test.
* testsuite/20_util/is_nothrow_convertible/value.cc: Remove
macro used by value_ext.cc test.
* testsuite/20_util/is_nothrow_convertible/value_ext.cc: Remove
test for non-standard __is_nothrow_invocable trait.
(cherry picked from commit 71c828f84572d933979468baf2cf744180258ee4)
Diff:
---
libstdc++-v3/include/std/type_traits | 45 +++++++++++-----------
.../20_util/is_nothrow_convertible/value.cc | 2 -
.../value_ext.cc => is_nothrow_invocable/91456.cc} | 19 ++++++---
3 files changed, 36 insertions(+), 30 deletions(-)
diff --git a/libstdc++-v3/include/std/type_traits b/libstdc++-v3/include/std/type_traits
index 2572d8edd69..d4e7200123c 100644
--- a/libstdc++-v3/include/std/type_traits
+++ b/libstdc++-v3/include/std/type_traits
@@ -1517,12 +1517,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
};
#pragma GCC diagnostic pop
- // is_nothrow_convertible for C++11
- template<typename _From, typename _To>
- struct __is_nothrow_convertible
- : public __is_nt_convertible_helper<_From, _To>::type
- { };
-
#if __cplusplus > 201703L
#define __cpp_lib_is_nothrow_convertible 201806L
/// is_nothrow_convertible
@@ -2906,7 +2900,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// The primary template is used for invalid INVOKE expressions.
template<typename _Result, typename _Ret,
bool = is_void<_Ret>::value, typename = void>
- struct __is_invocable_impl : false_type { };
+ struct __is_invocable_impl
+ : false_type
+ {
+ using __nothrow_type = false_type; // For is_nothrow_invocable_r
+ };
// Used for valid INVOKE and INVOKE<void> expressions.
template<typename _Result, typename _Ret>
@@ -2914,7 +2912,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
/* is_void<_Ret> = */ true,
__void_t<typename _Result::type>>
: true_type
- { };
+ {
+ using __nothrow_type = true_type; // For is_nothrow_invocable_r
+ };
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wctor-dtor-privacy"
@@ -2926,23 +2926,30 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{
private:
// The type of the INVOKE expression.
- // Unlike declval, this doesn't add_rvalue_reference.
- static typename _Result::type _S_get();
+ // Unlike declval, this doesn't add_rvalue_reference, so it respects
+ // guaranteed copy elision.
+ static typename _Result::type _S_get() noexcept;
template<typename _Tp>
- static void _S_conv(_Tp);
+ static void _S_conv(_Tp) noexcept;
// This overload is viable if INVOKE(f, args...) can convert to _Tp.
- template<typename _Tp, typename = decltype(_S_conv<_Tp>(_S_get()))>
- static true_type
+ template<typename _Tp, bool _Check_Noex = false,
+ typename = decltype(_S_conv<_Tp>(_S_get())),
+ bool _Noex = noexcept(_S_conv<_Tp>(_S_get()))>
+ static __bool_constant<_Check_Noex ? _Noex : true>
_S_test(int);
- template<typename _Tp>
+ template<typename _Tp, bool = false>
static false_type
_S_test(...);
public:
+ // For is_invocable_r
using type = decltype(_S_test<_Ret>(1));
+
+ // For is_nothrow_invocable_r
+ using __nothrow_type = decltype(_S_test<_Ret, true>(1));
};
#pragma GCC diagnostic pop
@@ -3073,15 +3080,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
};
/// @cond undocumented
- template<typename _Result, typename _Ret, typename = void>
- struct __is_nt_invocable_impl : false_type { };
-
template<typename _Result, typename _Ret>
- struct __is_nt_invocable_impl<_Result, _Ret,
- __void_t<typename _Result::type>>
- : __or_<is_void<_Ret>,
- __is_nothrow_convertible<typename _Result::type, _Ret>>
- { };
+ using __is_nt_invocable_impl
+ = typename __is_invocable_impl<_Result, _Ret>::__nothrow_type;
/// @endcond
/// std::is_nothrow_invocable_r
diff --git a/libstdc++-v3/testsuite/20_util/is_nothrow_convertible/value.cc b/libstdc++-v3/testsuite/20_util/is_nothrow_convertible/value.cc
index e9aded73624..a2686285052 100644
--- a/libstdc++-v3/testsuite/20_util/is_nothrow_convertible/value.cc
+++ b/libstdc++-v3/testsuite/20_util/is_nothrow_convertible/value.cc
@@ -21,9 +21,7 @@
#include <type_traits>
#include <testsuite_tr1.h>
-#ifndef IS_NT_CONVERTIBLE_DEFINED
using std::is_nothrow_convertible;
-#endif
void test01()
{
diff --git a/libstdc++-v3/testsuite/20_util/is_nothrow_convertible/value_ext.cc b/libstdc++-v3/testsuite/20_util/is_nothrow_invocable/91456.cc
similarity index 59%
rename from libstdc++-v3/testsuite/20_util/is_nothrow_convertible/value_ext.cc
rename to libstdc++-v3/testsuite/20_util/is_nothrow_invocable/91456.cc
index 0f896428537..abbbd1aade4 100644
--- a/libstdc++-v3/testsuite/20_util/is_nothrow_convertible/value_ext.cc
+++ b/libstdc++-v3/testsuite/20_util/is_nothrow_invocable/91456.cc
@@ -15,14 +15,21 @@
// with this library; see the file COPYING3. If not see
// <http://www.gnu.org/licenses/>.
-// { dg-do compile { target c++11 } }
+// { dg-do compile { target c++17 } }
+
+// PR 91456
+// std::function and std::is_invocable_r do not understand guaranteed elision
#include <type_traits>
-// Test the non-standard __is_nothrow_convertible trait
+#include <functional>
-template<typename From, typename To>
- using is_nothrow_convertible = std::__is_nothrow_convertible<From, To>;
+struct Immovable {
+ Immovable() = default;
+ Immovable(const Immovable&) = delete;
+ Immovable& operator=(const Immovable&) = delete;
+};
-#define IS_NT_CONVERTIBLE_DEFINED
-#include "value.cc"
+static_assert(std::is_nothrow_invocable_r_v<Immovable, Immovable(*)() noexcept>);
+static_assert(std::is_nothrow_invocable_r_v<const Immovable, Immovable(*)() noexcept>);
+static_assert(std::is_nothrow_invocable_r_v<Immovable, const Immovable(*)() noexcept>);
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2022-11-24 16:36 [gcc r12-8930] libstdc++: Fix std::is_nothrow_invocable_r for uncopyable prvalues [PR91456] Jonathan Wakely
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