[gcc r16-8526] libstdc++: Remove non_type and replace it with constant_wrapper in function_ref
Tomasz Kaminski
tkaminsk@gcc.gnu.org
Wed Apr 8 11:33:09 GMT 2026
https://gcc.gnu.org/g:52b44d966edc34611e01e505fee92f924a213df2
commit r16-8526-g52b44d966edc34611e01e505fee92f924a213df2
Author: Matthias Kretz <m.kretz@gsi.de>
Date: Tue Nov 11 16:27:34 2025 +0100
libstdc++: Remove non_type and replace it with constant_wrapper in function_ref
This implements P3948R1: constant_wrapper is the only tool needed
for passing constant expressions via function arguments.
This changes function_ref from nontype_t to constant_wrapper and
implements the ambiguity check (static_asert in function_ref
from constant_wrapper constructor).
In addition to P3948R1 this also includes the (forgotten) deduction
guide changes suggested in the draft PR [1].
[1] https://github.com/cplusplus/draft/pull/8878
libstdc++-v3/ChangeLog:
* include/bits/funcref_impl.h (function_ref::function_ref):
Change nontype_t parameter to constant_wrapper, and adjust
accordingly. Add static_assert detecting ambigous semantics.
(function_ref::operator=): Detect constant_wrapper rather than
nontype_t.
* include/bits/funcwrap.h (function_ref): Change nontype_t
parameter to constant_wrapper in deduction guides.
* include/bits/utility.h (std::nontype_t, std::nontype)
(std::__is_nontype_v): Remove.
(std::__is_constant_wrapper_v): Define.
* src/c++23/std.cc.in (std::nontype_t, std::nontype):
Remove exports.
* testsuite/20_util/function_ref/cw_cons_neg.cc: New tests
for ambiguity check.
* testsuite/20_util/function_ref/assign.cc: Replace nontype_t
with constant_wrapper and nontype with std::cw.
* testsuite/20_util/function_ref/call.cc: Likewise.
* testsuite/20_util/function_ref/cons.cc: Likewise.
* testsuite/20_util/function_ref/cons_neg.cc: Likewise.
* testsuite/20_util/function_ref/dangling.cc: Likewise.
* testsuite/20_util/function_ref/deduction.cc: Likewise.
* testsuite/20_util/function_ref/mutation.cc: Likewise.
Co-authored-by: Tomasz Kamiński <tkaminsk@redhat.com>
Reviewed-by: Jonathan Wakely <jwakely@redhat.com>
Signed-off-by: Matthias Kretz <m.kretz@gsi.de>
Signed-off-by: Tomasz Kamiński <tkaminsk@redhat.com>
Diff:
---
libstdc++-v3/include/bits/funcref_impl.h | 36 ++++++----
libstdc++-v3/include/bits/funcwrap.h | 13 ++--
libstdc++-v3/include/bits/utility.h | 23 ++----
libstdc++-v3/src/c++23/std.cc.in | 4 --
.../testsuite/20_util/function_ref/assign.cc | 27 ++++---
.../testsuite/20_util/function_ref/call.cc | 51 +++++++------
.../testsuite/20_util/function_ref/cons.cc | 83 +++++++++++-----------
.../testsuite/20_util/function_ref/cons_neg.cc | 17 +++--
.../testsuite/20_util/function_ref/cw_cons_neg.cc | 35 +++++++++
.../testsuite/20_util/function_ref/dangling.cc | 2 +-
.../testsuite/20_util/function_ref/deduction.cc | 48 ++++++-------
.../testsuite/20_util/function_ref/mutation.cc | 9 ++-
12 files changed, 185 insertions(+), 163 deletions(-)
diff --git a/libstdc++-v3/include/bits/funcref_impl.h b/libstdc++-v3/include/bits/funcref_impl.h
index 3d55c8406b09..9fcab570803f 100644
--- a/libstdc++-v3/include/bits/funcref_impl.h
+++ b/libstdc++-v3/include/bits/funcref_impl.h
@@ -129,12 +129,19 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 4256. Incorrect constrains for function_ref constructors from nontype
/// Target object is __fn. There is no bound object.
- template<auto __fn>
- requires __is_invocable_using<const decltype(__fn)&>
+ template<auto __cwfn, typename _Fn>
+ requires __is_invocable_using<const _Fn&>
constexpr
- function_ref(nontype_t<__fn>) noexcept
+ function_ref(constant_wrapper<__cwfn, _Fn>) noexcept
{
- using _Fn = remove_cv_t<decltype(__fn)>;
+ constexpr const _Fn& __fn = constant_wrapper<__cwfn, _Fn>::value;
+ if constexpr (sizeof...(_ArgTypes) > 0)
+ if constexpr ((... && _ConstExprParam<remove_cvref_t<_ArgTypes>>))
+ static_assert(!requires {
+ typename constant_wrapper<
+ std::__invoke(__fn, remove_cvref_t<_ArgTypes>::value...)>;
+ }, "cw<fn>(args...) should be equivalent to fn(args...)");
+
if constexpr (is_pointer_v<_Fn> || is_member_pointer_v<_Fn>)
static_assert(__fn != nullptr);
@@ -144,13 +151,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
/// Target object is equivalent to std::bind_front<_fn>(std::ref(__ref)).
/// Bound object is object referenced by second parameter.
- template<auto __fn, typename _Up, typename _Td = remove_reference_t<_Up>>
+ template<auto __cwfn, typename _Fn, typename _Up,
+ typename _Td = remove_reference_t<_Up>>
requires (!is_rvalue_reference_v<_Up&&>)
- && __is_invocable_using<const decltype(__fn)&, _Td _GLIBCXX_MOF_CV&>
+ && __is_invocable_using<const _Fn&, _Td _GLIBCXX_MOF_CV&>
constexpr
- function_ref(nontype_t<__fn>, _Up&& __ref) noexcept
+ function_ref(constant_wrapper<__cwfn, _Fn>, _Up&& __ref) noexcept
{
- using _Fn = remove_cv_t<decltype(__fn)>;
+ constexpr const _Fn& __fn = constant_wrapper<__cwfn, _Fn>::value;
if constexpr (is_pointer_v<_Fn> || is_member_pointer_v<_Fn>)
static_assert(__fn != nullptr);
@@ -166,12 +174,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
/// Target object is equivalent to std::bind_front<_fn>(__ptr).
/// Bound object is object pointed by second parameter (if any).
- template<auto __fn, typename _Td>
- requires __is_invocable_using<const decltype(__fn)&, _Td _GLIBCXX_MOF_CV*>
+ template< auto __cwfn, typename _Fn, typename _Td>
+ requires __is_invocable_using<const _Fn&, _Td _GLIBCXX_MOF_CV*>
constexpr
- function_ref(nontype_t<__fn>, _Td _GLIBCXX_MOF_CV* __ptr) noexcept
+ function_ref(constant_wrapper<__cwfn, _Fn>, _Td _GLIBCXX_MOF_CV* __ptr) noexcept
{
- using _Fn = remove_cv_t<decltype(__fn)>;
+ constexpr const _Fn& __fn = constant_wrapper<__cwfn, _Fn>::value;
if constexpr (is_pointer_v<_Fn> || is_member_pointer_v<_Fn>)
static_assert(__fn != nullptr);
if constexpr (is_member_pointer_v<_Fn>)
@@ -182,8 +190,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
template<typename _Tp>
- requires (!is_same_v<_Tp, function_ref>)
- && (!is_pointer_v<_Tp>) && (!__is_nontype_v<_Tp>)
+ requires (!is_same_v<_Tp, function_ref>) && (!is_pointer_v<_Tp>)
+ && (!__is_constant_wrapper_v<_Tp>)
function_ref&
operator=(_Tp) = delete;
diff --git a/libstdc++-v3/include/bits/funcwrap.h b/libstdc++-v3/include/bits/funcwrap.h
index 6441893d2135..b835e075295b 100644
--- a/libstdc++-v3/include/bits/funcwrap.h
+++ b/libstdc++-v3/include/bits/funcwrap.h
@@ -573,15 +573,16 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
requires is_function_v<_Fn>
function_ref(_Fn*) -> function_ref<_Fn>;
- template<auto __f, class _Fn = remove_pointer_t<decltype(__f)>>
- requires is_function_v<_Fn>
- function_ref(nontype_t<__f>) -> function_ref<_Fn>;
+ template<auto __cwfn, typename _Fn>
+ requires is_function_v<remove_pointer_t<_Fn>>
+ function_ref(constant_wrapper<__cwfn, _Fn>)
+ -> function_ref<remove_pointer_t<_Fn>>;
- template<auto __f, typename _Tp,
+ template<auto __cwfn, typename _Fn, typename _Tp,
typename _SignaturePtr =
- decltype(__polyfunc::__deduce_funcref<decltype(__f), _Tp&>())>
+ decltype(__polyfunc::__deduce_funcref<_Fn, _Tp&>())>
requires (!is_void_v<_SignaturePtr>)
- function_ref(nontype_t<__f>, _Tp&&)
+ function_ref(constant_wrapper<__cwfn, _Fn>, _Tp&&)
-> function_ref<remove_pointer_t<_SignaturePtr>>;
#endif // __glibcxx_function_ref
diff --git a/libstdc++-v3/include/bits/utility.h b/libstdc++-v3/include/bits/utility.h
index 970e63e81706..93e9e9f9dba2 100644
--- a/libstdc++-v3/include/bits/utility.h
+++ b/libstdc++-v3/include/bits/utility.h
@@ -458,6 +458,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{ return value; }
};
+ template<typename>
+ constexpr bool __is_constant_wrapper_v = false;
+
+ template<auto __cw, typename _Fn>
+ constexpr bool __is_constant_wrapper_v<constant_wrapper<__cw, _Fn>> = true;
+
template<_CwFixedValue _Tp>
constexpr auto cw = constant_wrapper<_Tp>{};
#endif
@@ -637,23 +643,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
inline constexpr sorted_equivalent_t sorted_equivalent{};
#endif
-#if __glibcxx_function_ref // >= C++26
- template<auto>
- struct nontype_t
- {
- explicit nontype_t() = default;
- };
-
- template<auto __val>
- constexpr nontype_t<__val> nontype{};
-
- template<typename>
- inline constexpr bool __is_nontype_v = false;
-
- template<auto __val>
- inline constexpr bool __is_nontype_v<nontype_t<__val>> = true;
-#endif
-
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace
diff --git a/libstdc++-v3/src/c++23/std.cc.in b/libstdc++-v3/src/c++23/std.cc.in
index db66677d55ba..3ac198716924 100644
--- a/libstdc++-v3/src/c++23/std.cc.in
+++ b/libstdc++-v3/src/c++23/std.cc.in
@@ -3651,10 +3651,6 @@ export namespace std
using std::make_integer_sequence;
using std::move;
using std::move_if_noexcept;
-#if __cpp_lib_function_ref
- using std::nontype_t;
- using std::nontype;
-#endif
using std::pair;
using std::swap;
using std::operator==;
diff --git a/libstdc++-v3/testsuite/20_util/function_ref/assign.cc b/libstdc++-v3/testsuite/20_util/function_ref/assign.cc
index 9b02dc49c2a3..521a35fc11e0 100644
--- a/libstdc++-v3/testsuite/20_util/function_ref/assign.cc
+++ b/libstdc++-v3/testsuite/20_util/function_ref/assign.cc
@@ -8,8 +8,7 @@
# error "Feature-test macro for function_ref has wrong value in <functional>"
#endif
-using std::nontype;
-using std::nontype_t;
+using std::constant_wrapper;
using std::function_ref;
using std::is_nothrow_move_assignable_v;
@@ -55,13 +54,13 @@ static_assert( ! is_assignable_v<function_ref<int(S)>, decltype(&S::x)> );
static_assert( ! is_assignable_v<function_ref<int(S)>, decltype(&S::f)> );
static_assert( is_nothrow_assignable_v<function_ref<int(S)>,
- nontype_t<funS>> );
+ constant_wrapper<funS>> );
static_assert( is_nothrow_assignable_v<function_ref<int(S)>,
- nontype_t<&funS>> );
+ constant_wrapper<&funS>> );
static_assert( is_nothrow_assignable_v<function_ref<int(S)>,
- nontype_t<&S::x>> );
+ constant_wrapper<&S::x>> );
static_assert( is_nothrow_assignable_v<function_ref<int(S)>,
- nontype_t<&S::f>> );
+ constant_wrapper<&S::f>> );
struct Q
{
void operator()() const;
@@ -75,22 +74,22 @@ static_assert( ! is_assignable_v<function_ref<void() const>, Q&> );
static_assert( ! is_assignable_v<function_ref<void() const>, const Q&> );
static_assert( is_nothrow_assignable_v<function_ref<void()>,
- nontype_t<Q{}>> );
+ constant_wrapper<Q{}>> );
static_assert( is_nothrow_assignable_v<function_ref<void() const>,
- nontype_t<Q{}>> );
+ constant_wrapper<Q{}>> );
constexpr bool
test_constexpr()
{
- function_ref<void(S)> fp(nontype<funS>);
- fp = nontype<funS>;
- fp = nontype<&funS>;
- fp = nontype<&S::x>;
- fp = nontype<&S::f>;
+ function_ref<void(S)> fp(std::cw<funS>);
+ fp = std::cw<funS>;
+ fp = std::cw<&funS>;
+ fp = std::cw<&S::x>;
+ fp = std::cw<&S::f>;
constexpr Q cq;
function_ref<void() const> fq(cq);
- fq = nontype<cq>;
+ fq = std::cw<cq>;
return true;
}
static_assert( test_constexpr() );
diff --git a/libstdc++-v3/testsuite/20_util/function_ref/call.cc b/libstdc++-v3/testsuite/20_util/function_ref/call.cc
index 49c6030b221a..386c8de790ab 100644
--- a/libstdc++-v3/testsuite/20_util/function_ref/call.cc
+++ b/libstdc++-v3/testsuite/20_util/function_ref/call.cc
@@ -4,7 +4,6 @@
#include <utility>
#include <testsuite_hooks.h>
-using std::nontype;
using std::function_ref;
using std::is_same_v;
@@ -43,7 +42,7 @@ test01()
VERIFY( f0() == 0 );
VERIFY( std::move(f0)() == 0 );
- function_ref<int()> f1{nontype<F{}>};
+ function_ref<int()> f1{std::cw<F{}>};
VERIFY( f1() == 1 );
VERIFY( std::move(f1)() == 1 );
@@ -53,7 +52,7 @@ test01()
VERIFY( std::move(f2)() == 1 );
VERIFY( std::move(std::as_const(f2))() == 1 );
- function_ref<int() const> f3{nontype<F{}>};
+ function_ref<int() const> f3{std::cw<F{}>};
VERIFY( f3() == 1 );
VERIFY( std::as_const(f3)() == 1 );
VERIFY( std::move(f3)() == 1 );
@@ -71,11 +70,11 @@ test02()
};
F::Arg arg;
- function_ref<int()> f0{std::nontype<F{}>, arg};
+ function_ref<int()> f0{std::cw<F{}>, arg};
VERIFY( f0() == 0 );
VERIFY( std::move(f0)() == 0 );
- function_ref<int() const> f1{std::nontype<F{}>, arg};
+ function_ref<int() const> f1{std::cw<F{}>, arg};
VERIFY( f1() == 1 );
VERIFY( std::as_const(f1)() == 1 );
}
@@ -91,11 +90,11 @@ test03()
};
F::Arg arg;
- function_ref<int()> f0{std::nontype<F{}>, &arg};
+ function_ref<int()> f0{std::cw<F{}>, &arg};
VERIFY( f0() == 0 );
VERIFY( std::move(f0)() == 0 );
- function_ref<int() const> f1{std::nontype<F{}>, &arg};
+ function_ref<int() const> f1{std::cw<F{}>, &arg};
VERIFY( f1() == 1 );
VERIFY( std::as_const(f1)() == 1 );
}
@@ -108,7 +107,7 @@ test04()
VERIFY( f0() == 0 );
VERIFY( std::move(f0)() == 0 );
- function_ref<int()> f1{nontype<fp>};
+ function_ref<int()> f1{std::cw<fp>};
VERIFY( f1() == 0 );
VERIFY( std::move(f1)() == 0 );
@@ -116,7 +115,7 @@ test04()
VERIFY( f2() == 0 );
VERIFY( std::move(f2)() == 0 );
- const function_ref<int() const> f3{nontype<fp>};
+ const function_ref<int() const> f3{std::cw<fp>};
VERIFY( f2() == 0 );
VERIFY( std::move(f2)() == 0 );
}
@@ -130,14 +129,14 @@ int callback_ref(ftype& f, int x) { return f(x); }
void
test05()
{
- function_ref<int(int)> r1(nontype<&callback_ptr>, &twice);
+ function_ref<int(int)> r1(std::cw<&callback_ptr>, &twice);
VERIFY( r1(2) == 4 );
- function_ref<int(int)> r2(nontype<&callback_ptr>, cube);
+ function_ref<int(int)> r2(std::cw<&callback_ptr>, cube);
VERIFY( r2(2) == 8 );
- function_ref<int(int)> r3(nontype<&callback_ref>, twice);
+ function_ref<int(int)> r3(std::cw<&callback_ref>, twice);
VERIFY( r3(3) == 6 );
- function_ref<int(int)> r4(nontype<&callback_ref>, cube);
+ function_ref<int(int)> r4(std::cw<&callback_ref>, cube);
VERIFY( r4(3) == 27 );
}
@@ -174,37 +173,37 @@ test06()
std::function_ref<const int&(int, int) const> e8(std::as_const(csr));
VERIFY( &e8(0, 0) == &s.v );
- std::function_ref<int&()> f1(std::nontype<&S::v>, sr);
+ std::function_ref<int&()> f1(std::cw<&S::v>, sr);
VERIFY( &f1() == &s.v );
- std::function_ref<const int&()> f2(std::nontype<&S::v>, sr);
+ std::function_ref<const int&()> f2(std::cw<&S::v>, sr);
VERIFY( &f2() == &s.v );
- std::function_ref<int&()> f3(std::nontype<&S::m>, sr);
+ std::function_ref<int&()> f3(std::cw<&S::m>, sr);
VERIFY( &f3() == &s.v );
- std::function_ref<const int&()> f4(std::nontype<&S::c>, sr);
+ std::function_ref<const int&()> f4(std::cw<&S::c>, sr);
VERIFY( &f4() == &s.v );
- std::function_ref<const int&()> f5(std::nontype<&S::v>, csr);
+ std::function_ref<const int&()> f5(std::cw<&S::v>, csr);
VERIFY( &f5() == &s.v );
- std::function_ref<const int&()> f6(std::nontype<&S::c>, sr);
+ std::function_ref<const int&()> f6(std::cw<&S::c>, sr);
VERIFY( &f6() == &s.v );
static_assert( !std::is_constructible_v<
std::function_ref<int&()>,
- std::nontype_t<&S::c>, std::reference_wrapper<S>&>
+ std::constant_wrapper<&S::c>, std::reference_wrapper<S>&>
);
- std::function_ref<int&()> f7(std::nontype<&S::v>, std::as_const(sr));
+ std::function_ref<int&()> f7(std::cw<&S::v>, std::as_const(sr));
VERIFY( &f7() == &s.v );
- std::function_ref<const int&()> f8(std::nontype<&S::m>, std::as_const(sr));
+ std::function_ref<const int&()> f8(std::cw<&S::m>, std::as_const(sr));
VERIFY( &f8() == &s.v );
// No rvalue reference_wrapper support
static_assert( !std::is_constructible_v<
std::function_ref<int&()>,
- std::nontype_t<&S::v>, std::reference_wrapper<S>>
+ std::constant_wrapper<&S::v>, std::reference_wrapper<S>>
);
static_assert( !std::is_constructible_v<
std::function_ref<int&()>,
- std::nontype_t<&S::v>, std::reference_wrapper<const S>>
+ std::constant_wrapper<&S::v>, std::reference_wrapper<const S>>
);
// reference to reference_wrapper are bound, so mutation are visible
@@ -232,9 +231,9 @@ test06()
{ return &x; };
// identity of reference_wrapper is preserved
- std::function_ref<const std::reference_wrapper<S>*()> g1(std::nontype<id>, sr);
+ std::function_ref<const std::reference_wrapper<S>*()> g1(std::cw<id>, sr);
VERIFY( g1() == &sr );
- std::function_ref<const std::reference_wrapper<const S>*()> g2(std::nontype<id>, csr);
+ std::function_ref<const std::reference_wrapper<const S>*()> g2(std::cw<id>, csr);
VERIFY( g2() == &csr );
}
diff --git a/libstdc++-v3/testsuite/20_util/function_ref/cons.cc b/libstdc++-v3/testsuite/20_util/function_ref/cons.cc
index a91f5ba3dab2..78aebd38a074 100644
--- a/libstdc++-v3/testsuite/20_util/function_ref/cons.cc
+++ b/libstdc++-v3/testsuite/20_util/function_ref/cons.cc
@@ -9,8 +9,7 @@
# error "Feature-test macro for function_ref has wrong value in <functional>"
#endif
-using std::nontype;
-using std::nontype_t;
+using std::constant_wrapper;
using std::function_ref;
using std::is_default_constructible_v;
@@ -60,31 +59,31 @@ static_assert( ! is_constructible_v<function_ref<int(S)>,
decltype(&S::f)> );
static_assert( is_nothrow_constructible_v<function_ref<int(S)>,
- nontype_t<funS>> );
+ constant_wrapper<funS>> );
static_assert( is_nothrow_constructible_v<function_ref<int(S)>,
- nontype_t<&funS>> );
+ constant_wrapper<&funS>> );
static_assert( is_nothrow_constructible_v<function_ref<int(S)>,
- nontype_t<&S::x>> );
+ constant_wrapper<&S::x>> );
static_assert( is_nothrow_constructible_v<function_ref<int(S)>,
- nontype_t<&S::f>> );
+ constant_wrapper<&S::f>> );
static_assert( is_nothrow_constructible_v<function_ref<int()>,
- nontype_t<funS>, S&> );
+ constant_wrapper<funS>, S&> );
static_assert( is_nothrow_constructible_v<function_ref<int()>,
- nontype_t<&funS>, S&> );
+ constant_wrapper<&funS>, S&> );
static_assert( is_nothrow_constructible_v<function_ref<int()>,
- nontype_t<&S::x>, S&> );
+ constant_wrapper<&S::x>, S&> );
static_assert( is_nothrow_constructible_v<function_ref<int()>,
- nontype_t<&S::f>, S&> );
+ constant_wrapper<&S::f>, S&> );
static_assert( ! is_constructible_v<function_ref<int()>,
- nontype_t<funS>, S*> );
+ constant_wrapper<funS>, S*> );
static_assert( ! is_constructible_v<function_ref<int()>,
- nontype_t<&funS>, S*> );
+ constant_wrapper<&funS>, S*> );
static_assert( is_nothrow_constructible_v<function_ref<int()>,
- nontype_t<&S::x>, S*> );
+ constant_wrapper<&S::x>, S*> );
static_assert( is_nothrow_constructible_v<function_ref<int()>,
- nontype_t<&S::f>, S*> );
+ constant_wrapper<&S::f>, S*> );
struct M
{
@@ -98,9 +97,9 @@ static_assert( ! is_constructible_v<function_ref<void()>, const M&> );
static_assert( ! is_constructible_v<function_ref<void() const>, M> );
static_assert( ! is_constructible_v<function_ref<void() const>, const M&> );
static_assert( ! is_constructible_v<function_ref<void()>,
- nontype_t<M{}>> );
+ constant_wrapper<M{}>> );
static_assert( ! is_constructible_v<function_ref<void() const>,
- nontype_t<M{}>> );
+ constant_wrapper<M{}>> );
struct Q
{
void operator()(int) const;
@@ -115,22 +114,22 @@ static_assert( is_nothrow_constructible_v<function_ref<void(int) const>, Q&> );
static_assert( is_nothrow_constructible_v<function_ref<void(int) const>, const Q&> );
static_assert( is_nothrow_constructible_v<function_ref<void(int)>,
- nontype_t<Q{}>> );
+ constant_wrapper<Q{}>> );
static_assert( is_nothrow_constructible_v<function_ref<void(int) const>,
- nontype_t<Q{}>> );
+ constant_wrapper<Q{}>> );
static_assert( is_nothrow_constructible_v<function_ref<void()>,
- nontype_t<Q{}>, int&> );
+ constant_wrapper<Q{}>, int&> );
static_assert( is_nothrow_constructible_v<function_ref<void() const>,
- nontype_t<Q{}>, int&> );
+ constant_wrapper<Q{}>, int&> );
static_assert( ! is_constructible_v<function_ref<void()>,
- nontype_t<Q{}>, int> );
+ constant_wrapper<Q{}>, int> );
static_assert( ! is_constructible_v<function_ref<void() const>,
- nontype_t<Q{}>, int> );
+ constant_wrapper<Q{}>, int> );
static_assert( is_nothrow_constructible_v<function_ref<void()>,
- nontype_t<Q{}>, int*> );
+ constant_wrapper<Q{}>, int*> );
static_assert( ! is_constructible_v<function_ref<void() const>,
- nontype_t<Q{}>, int*> );
+ constant_wrapper<Q{}>, int*> );
struct L
{
@@ -143,9 +142,9 @@ static_assert( ! is_constructible_v<function_ref<void()>, const L&> );
static_assert( ! is_constructible_v<function_ref<void() const>, L> );
static_assert( ! is_constructible_v<function_ref<void() const>, const L&> );
static_assert( ! is_constructible_v<function_ref<void()>,
- nontype_t<L{}>> );
+ constant_wrapper<L{}>> );
static_assert( ! is_constructible_v<function_ref<void() const>,
- nontype_t<L{}>> );
+ constant_wrapper<L{}>> );
struct R
{
@@ -159,24 +158,24 @@ static_assert( ! is_constructible_v<function_ref<void(float) const>, R&> );
static_assert( ! is_constructible_v<function_ref<void(float) const>, const R&> );
static_assert( ! is_constructible_v<function_ref<void(float)>,
- nontype_t<R{}>> );
+ constant_wrapper<R{}>> );
static_assert( ! is_constructible_v<function_ref<void(float) const>,
- nontype_t<R{}>> );
+ constant_wrapper<R{}>> );
constexpr bool
test_constexpr()
{
- function_ref<void(S)> fp1(nontype<funS>);
- function_ref<void(S)> fp3(nontype<&funS>);
- function_ref<void(S)> fp4(nontype<&S::x>);
- function_ref<void(S)> fp5(nontype<&S::f>);
+ function_ref<void(S)> fp1(std::cw<funS>);
+ function_ref<void(S)> fp3(std::cw<&funS>);
+ function_ref<void(S)> fp4(std::cw<&S::x>);
+ function_ref<void(S)> fp5(std::cw<&S::f>);
S s;
- function_ref<void()> fp6(nontype<&funS>, s);
- function_ref<void()> fp7(nontype<&S::x>, s);
- function_ref<void()> fp8(nontype<&S::x>, &s);
- function_ref<void()> fp9(nontype<&S::f>, s);
- function_ref<void()> fp10(nontype<&S::f>, &s);
+ function_ref<void()> fp6(std::cw<&funS>, s);
+ function_ref<void()> fp7(std::cw<&S::x>, s);
+ function_ref<void()> fp8(std::cw<&S::x>, &s);
+ function_ref<void()> fp9(std::cw<&S::f>, s);
+ function_ref<void()> fp10(std::cw<&S::f>, &s);
M m;
function_ref<void()> fm1(m);
@@ -190,13 +189,13 @@ test_constexpr()
function_ref<void(int)> fcq1(cq);
function_ref<void(int) const> f(cq);
- function_ref<void(int)> fcq3(nontype<cq>);
- function_ref<void(int) const> fcq4(nontype<cq>);
+ function_ref<void(int)> fcq3(std::cw<cq>);
+ function_ref<void(int) const> fcq4(std::cw<cq>);
int i = 0;
- function_ref<void()> fcq5(nontype<cq>, i);
- function_ref<void() const> fcq6(nontype<cq>, i);
- function_ref<void()> fcq7(nontype<cq>, &i);
+ function_ref<void()> fcq5(std::cw<cq>, i);
+ function_ref<void() const> fcq6(std::cw<cq>, i);
+ function_ref<void()> fcq7(std::cw<cq>, &i);
L l;
function_ref<void()> fl1(l);
diff --git a/libstdc++-v3/testsuite/20_util/function_ref/cons_neg.cc b/libstdc++-v3/testsuite/20_util/function_ref/cons_neg.cc
index 050090df3704..a426ac64cd53 100644
--- a/libstdc++-v3/testsuite/20_util/function_ref/cons_neg.cc
+++ b/libstdc++-v3/testsuite/20_util/function_ref/cons_neg.cc
@@ -2,7 +2,6 @@
#include <functional>
-using std::nontype;
using std::function_ref;
struct S
@@ -16,15 +15,15 @@ constexpr int(*fp)(S) = nullptr;
constexpr int S::*mdp = nullptr;
constexpr int (S::*mfp)() = nullptr;
-function_ref<int(S)> fd1(nontype<fp>); // { dg-error "from here" }
-function_ref<int(S)> fd2(nontype<mdp>); // { dg-error "from here" }
-function_ref<int(S)> fd3(nontype<mfp>); // { dg-error "from here" }
+function_ref<int(S)> fd1(std::cw<fp>); // { dg-error "from here" }
+function_ref<int(S)> fd2(std::cw<mdp>); // { dg-error "from here" }
+function_ref<int(S)> fd3(std::cw<mfp>); // { dg-error "from here" }
-function_ref<int()> br4(nontype<fp>, s); // { dg-error "from here" }
-function_ref<int()> br5(nontype<mdp>, s); // { dg-error "from here" }
-function_ref<int()> br6(nontype<mfp>, s); // { dg-error "from here" }
+function_ref<int()> br4(std::cw<fp>, s); // { dg-error "from here" }
+function_ref<int()> br5(std::cw<mdp>, s); // { dg-error "from here" }
+function_ref<int()> br6(std::cw<mfp>, s); // { dg-error "from here" }
-function_ref<int()> bp7(nontype<mdp>, &s); // { dg-error "from here" }
-function_ref<int()> bp8(nontype<mfp>, &s); // { dg-error "from here" }
+function_ref<int()> bp7(std::cw<mdp>, &s); // { dg-error "from here" }
+function_ref<int()> bp8(std::cw<mfp>, &s); // { dg-error "from here" }
// { dg-prune-output "static assertion failed" }
diff --git a/libstdc++-v3/testsuite/20_util/function_ref/cw_cons_neg.cc b/libstdc++-v3/testsuite/20_util/function_ref/cw_cons_neg.cc
new file mode 100644
index 000000000000..a295bc2ce31d
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/function_ref/cw_cons_neg.cc
@@ -0,0 +1,35 @@
+// { dg-do compile { target c++26 } }
+
+#include <functional>
+
+using std::function_ref;
+using std::constant_wrapper;
+
+struct S
+{
+ int operator()() const { return 1; }
+
+ // Non-constant, so cw<S{}>(cw<1>) call never unwrapps
+ int operator()(int) const { return 1; }
+ template<auto __cw>
+ int operator()(constant_wrapper<__cw, int>) const { return 1; }
+
+ // Constant, cw<S{}>(cw<1>, cw<2>) calls int overload
+ // while S{}(cw<1>, cw<1>) calls constant_wrapper overload
+ constexpr int operator()(int, int) const { return 1; }
+ template<auto __cw1, auto __cw2>
+ constexpr int operator()(constant_wrapper<__cw1, int>,
+ constant_wrapper<__cw2, int>)
+ { return 1; }
+};
+
+function_ref<int()> f0a(S{});
+
+function_ref<int(int)> f1a(S{});
+function_ref<int(constant_wrapper<2>)> f1b(std::cw<S{}>);
+
+function_ref<int(int, int)> f2a(std::cw<S{}>); // OK, runtime
+function_ref<int(constant_wrapper<1>, int)> f2b(std::cw<S{}>); // OK, still runtime
+function_ref<int(constant_wrapper<2>, constant_wrapper<3>)> f2c(std::cw<S{}>); // { dg-error "from here" }
+
+// { dg-prune-output "static assertion failed" }
diff --git a/libstdc++-v3/testsuite/20_util/function_ref/dangling.cc b/libstdc++-v3/testsuite/20_util/function_ref/dangling.cc
index 3cc782524f6e..4ef5d067555d 100644
--- a/libstdc++-v3/testsuite/20_util/function_ref/dangling.cc
+++ b/libstdc++-v3/testsuite/20_util/function_ref/dangling.cc
@@ -46,7 +46,7 @@ struct NonStatic {
{ return x + y + v; }
};
-constexpr auto vNonType = create(std::nontype<NonStatic{3}>);
+constexpr auto vNonType = create(std::cw<NonStatic{3}>);
struct StaticWins {
static int
diff --git a/libstdc++-v3/testsuite/20_util/function_ref/deduction.cc b/libstdc++-v3/testsuite/20_util/function_ref/deduction.cc
index b034c7af0725..63c3f6ea7e3c 100644
--- a/libstdc++-v3/testsuite/20_util/function_ref/deduction.cc
+++ b/libstdc++-v3/testsuite/20_util/function_ref/deduction.cc
@@ -4,15 +4,13 @@
#include <type_traits>
using std::is_same_v;
-using std::nontype;
-using std::nontype_t;
using std::function_ref;
int i = 0;
template<auto f, class... Args>
concept deductible = requires (Args&... args)
- { std::function_ref(std::nontype<f>, args...); };
+ { std::function_ref(std::cw<f>, args...); };
static_assert( !deductible<1> );
static_assert( !deductible<1, int> );
@@ -24,9 +22,9 @@ static_assert( is_same_v<decltype(function_ref(f0)),
function_ref<void()>> );
static_assert( is_same_v<decltype(function_ref(f0n)),
function_ref<void() noexcept>> );
-static_assert( is_same_v<decltype(function_ref(nontype<f0>)),
+static_assert( is_same_v<decltype(function_ref(std::cw<f0>)),
function_ref<void()>> );
-static_assert( is_same_v<decltype(function_ref(nontype<f0n>)),
+static_assert( is_same_v<decltype(function_ref(std::cw<f0n>)),
function_ref<void() noexcept>> );
static_assert( !deductible<f0, char*> );
static_assert( !deductible<f0n, char*> );
@@ -38,13 +36,13 @@ static_assert( is_same_v<decltype(function_ref(f1)),
function_ref<void(int)>> );
static_assert( is_same_v<decltype(function_ref(f1n)),
function_ref<void(int) noexcept>> );
-static_assert( is_same_v<decltype(function_ref(nontype<f1>)),
+static_assert( is_same_v<decltype(function_ref(std::cw<f1>)),
function_ref<void(int)>> );
-static_assert( is_same_v<decltype(function_ref(nontype<f1n>)),
+static_assert( is_same_v<decltype(function_ref(std::cw<f1n>)),
function_ref<void(int) noexcept>> );
-static_assert( is_same_v<decltype(function_ref(nontype<f1>, i)),
+static_assert( is_same_v<decltype(function_ref(std::cw<f1>, i)),
function_ref<void()>> );
-static_assert( is_same_v<decltype(function_ref(nontype<f1n>, i)),
+static_assert( is_same_v<decltype(function_ref(std::cw<f1n>, i)),
function_ref<void() noexcept>> );
static_assert( !deductible<f1, char*> );
static_assert( !deductible<f1n, char*> );
@@ -56,13 +54,13 @@ static_assert( is_same_v<decltype(function_ref(f2)),
function_ref<void(int*, int)>> );
static_assert( is_same_v<decltype(function_ref(f2n)),
function_ref<void(int*, int) noexcept>> );
-static_assert( is_same_v<decltype(function_ref(nontype<f2>)),
+static_assert( is_same_v<decltype(function_ref(std::cw<f2>)),
function_ref<void(int*, int)>> );
-static_assert( is_same_v<decltype(function_ref(nontype<f2n>)),
+static_assert( is_same_v<decltype(function_ref(std::cw<f2n>)),
function_ref<void(int*, int) noexcept>> );
-static_assert( is_same_v<decltype(function_ref(nontype<f2>, &i)),
+static_assert( is_same_v<decltype(function_ref(std::cw<f2>, &i)),
function_ref<void(int)>> );
-static_assert( is_same_v<decltype(function_ref(nontype<f2n>, &i)),
+static_assert( is_same_v<decltype(function_ref(std::cw<f2n>, &i)),
function_ref<void(int) noexcept>> );
static_assert( !deductible<f2, char*> );
static_assert( !deductible<f2n, char*> );
@@ -88,40 +86,40 @@ struct S
S s{};
const S cs{};
-static_assert( is_same_v<decltype(function_ref(nontype<&S::mem>, s)),
+static_assert( is_same_v<decltype(function_ref(std::cw<&S::mem>, s)),
function_ref<int&() noexcept>> );
-static_assert( is_same_v<decltype(function_ref(nontype<&S::mem>, cs)),
+static_assert( is_same_v<decltype(function_ref(std::cw<&S::mem>, cs)),
function_ref<const int&() noexcept>> );
-static_assert( is_same_v<decltype(function_ref(nontype<&S::mem>, &s)),
+static_assert( is_same_v<decltype(function_ref(std::cw<&S::mem>, &s)),
function_ref<int&() noexcept>> );
-static_assert( is_same_v<decltype(function_ref(nontype<&S::mem>, &cs)),
+static_assert( is_same_v<decltype(function_ref(std::cw<&S::mem>, &cs)),
function_ref<const int&() noexcept>> );
static_assert( !deductible<&S::mem, int> );
-static_assert( is_same_v<decltype(function_ref(nontype<&S::f>, s)),
+static_assert( is_same_v<decltype(function_ref(std::cw<&S::f>, s)),
function_ref<int()>> );
-static_assert( is_same_v<decltype(function_ref(nontype<&S::fn>, &s)),
+static_assert( is_same_v<decltype(function_ref(std::cw<&S::fn>, &s)),
function_ref<int() noexcept>> );
static_assert( !deductible<&S::f, char*> );
static_assert( !deductible<&S::fn, char*> );
static_assert( !deductible<&S::f, const S> );
static_assert( !deductible<&S::fn, const S> );
-static_assert( is_same_v<decltype(function_ref(nontype<&S::fc>, &s)),
+static_assert( is_same_v<decltype(function_ref(std::cw<&S::fc>, &s)),
function_ref<int(int)>> );
-static_assert( is_same_v<decltype(function_ref(nontype<&S::fcn>, s)),
+static_assert( is_same_v<decltype(function_ref(std::cw<&S::fcn>, s)),
function_ref<int(int) noexcept>> );
static_assert( !deductible<&S::fc, char*> );
static_assert( !deductible<&S::fcn, char*> );
-static_assert( is_same_v<decltype(function_ref(nontype<&S::fl>, &s)),
+static_assert( is_same_v<decltype(function_ref(std::cw<&S::fl>, &s)),
function_ref<int(int)>> );
-static_assert( is_same_v<decltype(function_ref(nontype<&S::fln>, s)),
+static_assert( is_same_v<decltype(function_ref(std::cw<&S::fln>, s)),
function_ref<int(int) noexcept>> );
-static_assert( is_same_v<decltype(function_ref(nontype<&S::fcl>, s)),
+static_assert( is_same_v<decltype(function_ref(std::cw<&S::fcl>, s)),
function_ref<int(float)>> );
-static_assert( is_same_v<decltype(function_ref(nontype<&S::fcln>, &s)),
+static_assert( is_same_v<decltype(function_ref(std::cw<&S::fcln>, &s)),
function_ref<int(float) noexcept>> );
static_assert( !deductible<&S::fr, char*> );
diff --git a/libstdc++-v3/testsuite/20_util/function_ref/mutation.cc b/libstdc++-v3/testsuite/20_util/function_ref/mutation.cc
index 32c6931e9a80..d55f4facbda1 100644
--- a/libstdc++-v3/testsuite/20_util/function_ref/mutation.cc
+++ b/libstdc++-v3/testsuite/20_util/function_ref/mutation.cc
@@ -3,7 +3,6 @@
#include <functional>
#include <testsuite_hooks.h>
-using std::nontype;
using std::function_ref;
void
@@ -55,8 +54,8 @@ test02()
};
S s{10};
- function_ref<int()> r1(nontype<&S::x>, s);
- function_ref<long()> r2(nontype<&S::x>, &s);
+ function_ref<int()> r1(std::cw<&S::x>, s);
+ function_ref<long()> r2(std::cw<&S::x>, &s);
VERIFY( r1() == 10 );
VERIFY( r2() == 10 );
@@ -66,8 +65,8 @@ test02()
VERIFY( r1() == 20 );
VERIFY( r2() == 20 );
- r1 = function_ref<int()>(nontype<&S::f>, &s);
- r2 = function_ref<long()>(nontype<&S::f>, s);
+ r1 = function_ref<int()>(std::cw<&S::f>, &s);
+ r2 = function_ref<long()>(std::cw<&S::f>, s);
VERIFY( r1() == 20 );
VERIFY( r2() == 20 );
More information about the Libstdc++-cvs
mailing list