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Implement LWG 2769, Redundant const in the return type of any_cast(const any&).

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Implement LWG 2769, Redundant const in the return type of
any_cast(const any&).
* include/std/any (_AnyCast): New.
(any_cast(const any&)): Use it and add an explicit cast for return.
(any_cast(any&)): Likewise.
(any_cast(any&&)): Likewise.
* testsuite/20_util/any/misc/any_cast.cc: Add a test for a type
that has an explicit copy constructor.
*testsuite/20_util/any/misc/any_cast_neg.cc: Adjust.

From-SVN: r243739
This commit is contained in:
Ville Voutilainen 2016-12-16 13:34:45 +02:00 committed by Ville Voutilainen
parent b7fc43d7c7
commit 6254952346
4 changed files with 36 additions and 9 deletions
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12
libstdc++-v3/ChangeLog
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@ -1,3 +1,15 @@
2016-12-16 Ville Voutilainen <ville.voutilainen@gmail.com>
Implement LWG 2769, Redundant const in the return type of
any_cast(const any&).
* include/std/any (_AnyCast): New.
(any_cast(const any&)): Use it and add an explicit cast for return.
(any_cast(any&)): Likewise.
(any_cast(any&&)): Likewise.
* testsuite/20_util/any/misc/any_cast.cc: Add a test for a type
that has an explicit copy constructor.
* testsuite/20_util/any/misc/any_cast_neg.cc: Adjust.
2016-12-15 Jonathan Wakely <jwakely@redhat.com>
PR libstdc++/59170

18
libstdc++-v3/include/std/any
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@ -433,6 +433,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
return any(in_place_type<_Tp>, __il, std::forward<_Args>(__args)...);
}
template <typename _Tp>
using _AnyCast = remove_cv_t<remove_reference_t<_Tp>>;
/**
* @brief Access the contained object.
*
@ -448,9 +450,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{
static_assert(any::__is_valid_cast<_ValueType>(),
"Template argument must be a reference or CopyConstructible type");
auto __p = any_cast<add_const_t<remove_reference_t<_ValueType>>>(&__any);
auto __p = any_cast<_AnyCast<_ValueType>>(&__any);
if (__p)
return *__p;
return static_cast<_ValueType>(*__p);
__throw_bad_any_cast();
}
@ -471,9 +473,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{
static_assert(any::__is_valid_cast<_ValueType>(),
"Template argument must be a reference or CopyConstructible type");
auto __p = any_cast<remove_reference_t<_ValueType>>(&__any);
auto __p = any_cast<_AnyCast<_ValueType>>(&__any);
if (__p)
return *__p;
return static_cast<_ValueType>(*__p);
__throw_bad_any_cast();
}
@ -485,9 +487,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{
static_assert(any::__is_valid_cast<_ValueType>(),
"Template argument must be a reference or CopyConstructible type");
auto __p = any_cast<remove_reference_t<_ValueType>>(&__any);
auto __p = any_cast<_AnyCast<_ValueType>>(&__any);
if (__p)
return *__p;
return static_cast<_ValueType>(*__p);
__throw_bad_any_cast();
}
@ -499,9 +501,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{
static_assert(any::__is_valid_cast<_ValueType>(),
"Template argument must be a reference or CopyConstructible type");
auto __p = any_cast<remove_reference_t<_ValueType>>(&__any);
auto __p = any_cast<_AnyCast<_ValueType>>(&__any);
if (__p)
return std::move(*__p);
return static_cast<_ValueType>(std::move(*__p));
__throw_bad_any_cast();
}
// @}

13
libstdc++-v3/testsuite/20_util/any/misc/any_cast.cc
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@ -106,9 +106,22 @@ void test03()
MoveDeleted&& md3 = any_cast<MoveDeleted&&>(any(std::move(md)));
}
void test04()
{
struct ExplicitCopy
{
ExplicitCopy() = default;
explicit ExplicitCopy(const ExplicitCopy&) = default;
};
any x = ExplicitCopy();
ExplicitCopy ec{any_cast<ExplicitCopy>(x)};
ExplicitCopy ec2{any_cast<ExplicitCopy>(std::move(x))};
}
int main()
{
test01();
test02();
test03();
test04();
}

2
libstdc++-v3/testsuite/20_util/any/misc/any_cast_neg.cc
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@ -26,5 +26,5 @@ void test01()
using std::any_cast;
const any y(1);
any_cast<int&>(y); // { dg-error "qualifiers" "" { target { *-*-* } } 453 }
any_cast<int&>(y); // { dg-error "invalid static_cast" "" { target { *-*-* } } 455 }
}