On Fri, Nov 14, 2025 at 4:16 AM Patrick Palka <[email protected]> wrote:
> On Thu, 13 Nov 2025, Tomasz Kamiński wrote:
>
> > The iterators for transform views (views::transform,
> views::zip_transform,
> > and views::adjacent_transform) now store a __detail::__func_handle
> instead
> > of a pointer to the view object (_M_parent).
> >
> > The behavior of the __func_handle specialization depends on the
> _FunctorType
> > template parameter:
> > * _FunctionPtr: Used if the functor is a function pointer. The pointer is
> > stored directly in __func_handle and the iterator, avoiding double
> > indirection through a pointer to the function pointer.
> > * _MemberPointer: Used for data or function member pointers. This behaves
> > similarly to _FunctionPtr, but uses __invoke for invocations.
> > * _StaticOperator: Used if the operator() selected by overload resolution
> > for the iterator reference is static. In this case, __func_handle is
> empty,
> > reducing the iterator size.
> > * _Statefull: Used for all remaining cases. __func_handle stores a
> pointer
> > to the functor object stored within the view. Only for this
> specialization is
> > the cv-qualification of the functor template parameter (_Fn)
> relevant, and
> > both const and mutable specializations are generated.
>
> FWIW it's spelled 'stateful' with just one l.
>
> I guess you concluded that this optimization is unsafe for empty objects
> with non-static operator()?
>
Yes, I do not think anything in standard clearly states the that following
is
allowed to fail:
struct Obfuscate
{
int operator()(int x) const
{ return x + static_assert<unintptr_t>(this); }
};
std::vector<int> v{1, 2, 3, 4, 5};
auto tv = v | std::transform(Obfuscate{});
VERIFY( ranges::equal(tv, tv) );
But storing an empty object in an iterator will break.
> >
> > As a consequence of these changes, the iterators of transform views no
> longer
> > depend on the view object when __func_handle is specialized for values
> other
> > than _Statefull. The corresponding views are not marked as
> borrowed_range,
> > as they are not marked as such in the standard.
> >
> > Storing function member pointers directly increases the iterator size in
> that
> > specific case, but this is deemed beneficial for consistent treatment of
> > function and data member pointers.
> >
> > To avoid materializing temporaries when the underlying iterator(s)
> return a
> > prvalue, the _M_call_deref and _M_call_subscript methods of
> __func_handle are
> > defined to accept the iterator(s), which are then dereferenced as
> arguments
> > of the functor.
> >
> > Using _Fd::operator()(*__iters...) inside requires expression is only
> > supported since clang-20, however at the point of GCC-16 release,
> clang-22
> > should be already available.
> >
> > libstdc++-v3/ChangeLog:
> >
> > * include/std/ranges (__detail::__func_handle)
> > (__detail::func_handle_t): Define.
> > (transform_view::_Iterator, zip_transform_view::_Iterator)
> > (adjacent_tranform_view::_Iterator): Replace pointer to view
> > (_M_parent) with pointer to functor (_M_fun). Update constructors
> > to cosntruct _M_fun from *__parent->_M_fun. Define operator* and
> > operator[] in terms of _M_call_deref and _M_call_subscript.
> > * testsuite/std/ranges/adaptors/adjacent_transform/1.cc: New tests.
> > * testsuite/std/ranges/adaptors/transform.cc: New tests.
> > * testsuite/std/ranges/zip_transform/1.cc: New tests.
> > ---
> > Tested transform view files locally. More testing in progress.
> >
> > libstdc++-v3/include/std/ranges | 214 +++++++++++++++---
> > .../ranges/adaptors/adjacent_transform/1.cc | 97 ++++++++
> > .../std/ranges/adaptors/transform.cc | 118 +++++++++-
> > .../testsuite/std/ranges/zip_transform/1.cc | 101 +++++++++
> > 4 files changed, 493 insertions(+), 37 deletions(-)
> >
> > diff --git a/libstdc++-v3/include/std/ranges
> b/libstdc++-v3/include/std/ranges
> > index ae57b9a0809..28b4f1d2b90 100644
> > --- a/libstdc++-v3/include/std/ranges
> > +++ b/libstdc++-v3/include/std/ranges
> > @@ -286,6 +286,138 @@ namespace ranges
> > operator->() const noexcept
> > { return std::__addressof(_M_value); }
> > };
> > +
> > + enum class _FunctorType
> > + {
> > + _FunctionPtr,
> > + _MemberPtr,
> > + _StaticOperator,
> > + _Statefull,
> > + };
> > +
> > + template<typename _Fn, _FunctorType __ft>
> > + struct __func_handle
> > + {
> > + __func_handle() = default;
> > +
> > + constexpr explicit
> > + __func_handle(_Fn& __func) noexcept
> > + : _M_ptr(std::addressof(__func))
> > + { }
> > +
> > + template<typename _Un>
> > + requires (!is_const_v<_Un>) && is_same_v<const _Un, _Fn>
> > + constexpr explicit
> > + __func_handle(__func_handle<_Un, __ft> __other) noexcept
> > + : _M_ptr(__other._M_ptr)
> > + { }
> > +
> > + template<typename... _Iters>
> > + constexpr decltype(auto)
> > + _M_call_deref(const _Iters&... __iters) const
> > + noexcept(noexcept((*_M_ptr)(*__iters...)))
> > + { return (*_M_ptr)(*__iters...); }
> > +
> > + template<typename _DistType, typename... _Iters>
> > + constexpr decltype(auto)
> > + _M_call_subscript(const _DistType __n, const _Iters&... __iters)
> const
> > +
> noexcept(noexcept((*_M_ptr)(__iters[iter_difference_t<_Iters>(__n)]...)))
> > + { return (*_M_ptr)(__iters[iter_difference_t<_Iters>(__n)]...); }
> > +
> > + private:
> > + _Fn* _M_ptr = nullptr;
> > +
> > + template<typename, _FunctorType>
> > + friend struct __func_handle;
> > + };
> > +
> > + template<typename _Fn>
> > + struct __func_handle<_Fn, _FunctorType::_FunctionPtr>
> > + {
> > + __func_handle() = default;
> > +
> > + constexpr explicit
> > + __func_handle(_Fn __func) noexcept
> > + : _M_ptr(__func)
> > + { }
> > +
> > + template<typename... _Iters>
> > + constexpr decltype(auto)
> > + _M_call_deref(const _Iters&... __iters) const
> > + noexcept(noexcept(_M_ptr(*__iters...)))
> > + { return _M_ptr(*__iters...); }
> > +
> > + template<typename _DistType, typename... _Iters>
> > + constexpr decltype(auto)
> > + _M_call_subscript(const _DistType __n, const _Iters&... __iters)
> const
> > +
> noexcept(noexcept(_M_ptr(__iters[iter_difference_t<_Iters>(__n)]...)))
> > + { return _M_ptr(__iters[iter_difference_t<_Iters>(__n)]...); }
> > +
> > + private:
> > + _Fn _M_ptr = nullptr;
> > + };
> > +
> > + template<typename _Fn>
> > + struct __func_handle<_Fn, _FunctorType::_MemberPtr>
> > + {
> > + __func_handle() = default;
> > +
> > + constexpr explicit
> > + __func_handle(_Fn __func) noexcept
> > + : _M_ptr(__func)
> > + {}
> > +
> > + template<typename... _Iters>
> > + constexpr decltype(auto)
> > + _M_call_deref(const _Iters&... __iters) const
> > + noexcept(noexcept(std::__invoke(_M_ptr, *__iters...)))
> > + { return std::__invoke(_M_ptr, *__iters...); }
> > +
> > + template<typename _DistType, typename... _Iters>
> > + constexpr decltype(auto)
> > + _M_call_subscript(const _DistType __n, const _Iters&... __iters)
> const
> > + noexcept(noexcept(std::__invoke(_M_ptr,
> __iters[iter_difference_t<_Iters>(__n)]...)))
> > + { return std::__invoke(_M_ptr,
> __iters[iter_difference_t<_Iters>(__n)]...); }
> > +
> > + private:
> > + _Fn _M_ptr = nullptr;
> > + };
> > +
> > + template<typename _Fn>
> > + struct __func_handle<_Fn, _FunctorType::_StaticOperator>
> > + {
> > + __func_handle() = default;
> > +
> > + constexpr explicit
> > + __func_handle(const _Fn&) noexcept
> > + {}
> > +
> > + template<typename... _Iters>
> > + static constexpr decltype(auto)
> > + _M_call_deref(const _Iters&... __iters)
> > + noexcept(noexcept(_Fn::operator()(*__iters...)))
> > + { return _Fn::operator()(*__iters...); }
> > +
> > + template<typename _DistType, typename... _Iters>
> > + static constexpr decltype(auto)
> > + _M_call_subscript(_DistType __n, const _Iters&... __iters)
> > +
>
> noexcept(noexcept(_Fn::operator()(__iters[iter_difference_t<_Iters>(__n)]...)))
> > + { return
> _Fn::operator()(__iters[iter_difference_t<_Iters>(__n)]...); }
> > + };
> > +
> > + template<typename _Fn, typename... _Iters>
> > + using __func_handle_t = decltype([] {
> > + using _Fd = remove_cv_t<_Fn>;
> > + if constexpr (is_member_pointer_v<_Fd>)
> > + return __func_handle<_Fd, _FunctorType::_MemberPtr>();
> > + else if constexpr (std::is_function_v<remove_pointer_t<_Fd>>)
> > + return __func_handle<_Fd, _FunctorType::_FunctionPtr>();
> > + else if constexpr (requires (const _Iters&... __iters)
> > + { _Fd::operator()(*__iters...); })
> > + return __func_handle<_Fd, _FunctorType::_StaticOperator>();
> > + else
> > + return __func_handle<_Fn, _FunctorType::_Statefull>();
> > + }());
> > } // namespace __detail
> >
> > /// A view that contains exactly one element.
> > @@ -1874,6 +2006,10 @@ namespace views::__adaptor
> > private:
> > using _Parent = __detail::__maybe_const_t<_Const,
> transform_view>;
> > using _Base = transform_view::_Base<_Const>;
> > + using _Base_iter = iterator_t<_Base>;
> > + using _Func_handle = __detail::__func_handle_t<
> > + __detail::__maybe_const_t<_Const, _Fp>,
> > + _Base_iter>;
> >
> > static auto
> > _S_iter_concept()
> > @@ -1888,10 +2024,8 @@ namespace views::__adaptor
> > return input_iterator_tag{};
> > }
> >
> > - using _Base_iter = iterator_t<_Base>;
> > -
> > _Base_iter _M_current = _Base_iter();
> > - _Parent* _M_parent = nullptr;
> > + [[no_unique_address]] _Func_handle _M_fun;
> >
> > public:
> > using iterator_concept = decltype(_S_iter_concept());
> > @@ -1904,16 +2038,20 @@ namespace views::__adaptor
> > _Iterator() requires default_initializable<_Base_iter> = default;
> >
> > constexpr
> > - _Iterator(_Parent* __parent, _Base_iter __current)
> > - : _M_current(std::move(__current)),
> > - _M_parent(__parent)
> > + _Iterator(_Func_handle __fun, _Base_iter __current)
> > + : _M_current(std::move(__current)), _M_fun(__fun)
> > { }
> >
> > + constexpr
> > + _Iterator(_Parent* __parent, _Base_iter __current)
> > + : _M_current(std::move(__current)), _M_fun(*__parent->_M_fun)
> > + {}
> > +
> > constexpr
> > _Iterator(_Iterator<!_Const> __i)
> > requires _Const
> > && convertible_to<iterator_t<_Vp>, _Base_iter>
> > - : _M_current(std::move(__i._M_current)),
> _M_parent(__i._M_parent)
> > + : _M_current(std::move(__i._M_current)), _M_fun(__i._M_fun)
> > { }
> >
> > constexpr const _Base_iter&
> > @@ -1926,8 +2064,8 @@ namespace views::__adaptor
> >
> > constexpr decltype(auto)
> > operator*() const
> > - noexcept(noexcept(std::__invoke(*_M_parent->_M_fun,
> *_M_current)))
> > - { return std::__invoke(*_M_parent->_M_fun, *_M_current); }
> > + noexcept(noexcept(_M_fun._M_call_deref(_M_current)))
> > + { return _M_fun._M_call_deref(_M_current); }
> >
> > constexpr _Iterator&
> > operator++()
> > @@ -1980,7 +2118,7 @@ namespace views::__adaptor
> > constexpr decltype(auto)
> > operator[](difference_type __n) const
> > requires random_access_range<_Base>
> > - { return std::__invoke(*_M_parent->_M_fun, _M_current[__n]); }
> > + { return _M_fun._M_call_subscript(__n, _M_current); }
> >
> > friend constexpr bool
> > operator==(const _Iterator& __x, const _Iterator& __y)
> > @@ -2018,17 +2156,17 @@ namespace views::__adaptor
> > friend constexpr _Iterator
> > operator+(_Iterator __i, difference_type __n)
> > requires random_access_range<_Base>
> > - { return {__i._M_parent, __i._M_current + __n}; }
> > + { return {__i._M_fun, __i._M_current + __n}; }
> >
> > friend constexpr _Iterator
> > operator+(difference_type __n, _Iterator __i)
> > requires random_access_range<_Base>
> > - { return {__i._M_parent, __i._M_current + __n}; }
> > + { return {__i._M_fun, __i._M_current + __n}; }
> >
> > friend constexpr _Iterator
> > operator-(_Iterator __i, difference_type __n)
> > requires random_access_range<_Base>
> > - { return {__i._M_parent, __i._M_current - __n}; }
> > + { return {__i._M_fun, __i._M_current - __n}; }
> >
> > // _GLIBCXX_RESOLVE_LIB_DEFECTS
> > // 3483. transform_view::iterator's difference is overconstrained
> > @@ -5126,13 +5264,21 @@ namespace views::__adaptor
> > class zip_transform_view<_Fp, _Vs...>::_Iterator : public
> __iter_cat<_Const>
> > {
> > using _Parent = __detail::__maybe_const_t<_Const,
> zip_transform_view>;
> > + using _Fun_handle = __detail::__func_handle_t<
> > + __detail::__maybe_const_t<_Const, _Fp>,
> > + iterator_t<__detail::__maybe_const_t<_Const,
> _Vs>>...>;
> >
> > - _Parent* _M_parent = nullptr;
> > + [[no_unique_address]] _Fun_handle _M_fun;
> > __ziperator<_Const> _M_inner;
> >
> > + constexpr
> > + _Iterator(_Fun_handle __fun, __ziperator<_Const> __inner)
> > + : _M_fun(__fun), _M_inner(std::move(__inner))
> > + { }
> > +
> > constexpr
> > _Iterator(_Parent& __parent, __ziperator<_Const> __inner)
> > - : _M_parent(std::__addressof(__parent)),
> _M_inner(std::move(__inner))
> > + : _M_fun(*__parent._M_fun), _M_inner(std::move(__inner))
> > { }
> >
> > friend class zip_transform_view;
> > @@ -5150,14 +5296,14 @@ namespace views::__adaptor
> > constexpr
> > _Iterator(_Iterator<!_Const> __i)
> > requires _Const && convertible_to<__ziperator<false>,
> __ziperator<_Const>>
> > - : _M_parent(__i._M_parent), _M_inner(std::move(__i._M_inner))
> > + : _M_fun(__i._M_fun), _M_inner(std::move(__i._M_inner))
> > { }
> >
> > constexpr decltype(auto)
> > operator*() const
> > {
> > return std::apply([&](const auto&... __iters) -> decltype(auto) {
> > - return std::__invoke(*_M_parent->_M_fun, *__iters...);
> > + return _M_fun._M_call_deref(__iters...);
> > }, _M_inner._M_current);
> > }
> >
> > @@ -5213,7 +5359,7 @@ namespace views::__adaptor
> > operator[](difference_type __n) const requires
> random_access_range<_Base<_Const>>
> > {
> > return std::apply([&]<typename... _Is>(const _Is&... __iters) ->
> decltype(auto) {
> > - return std::__invoke(*_M_parent->_M_fun,
> __iters[iter_difference_t<_Is>(__n)]...);
> > + return _M_fun._M_call_subscript(__n, __iters...);
> > }, _M_inner._M_current);
> > }
> >
> > @@ -5230,17 +5376,17 @@ namespace views::__adaptor
> > friend constexpr _Iterator
> > operator+(const _Iterator& __i, difference_type __n)
> > requires random_access_range<_Base<_Const>>
> > - { return _Iterator(*__i._M_parent, __i._M_inner + __n); }
> > + { return _Iterator(__i._M_fun, __i._M_inner + __n); }
> >
> > friend constexpr _Iterator
> > operator+(difference_type __n, const _Iterator& __i)
> > requires random_access_range<_Base<_Const>>
> > - { return _Iterator(*__i._M_parent, __i._M_inner + __n); }
> > + { return _Iterator(__i._M_fun, __i._M_inner + __n); }
> >
> > friend constexpr _Iterator
> > operator-(const _Iterator& __i, difference_type __n)
> > requires random_access_range<_Base<_Const>>
> > - { return _Iterator(*__i._M_parent, __i._M_inner - __n); }
> > + { return _Iterator(__i._M_fun, __i._M_inner - __n); }
> >
> > friend constexpr difference_type
> > operator-(const _Iterator& __x, const _Iterator& __y)
> > @@ -5807,13 +5953,23 @@ namespace views::__adaptor
> > {
> > using _Parent = __detail::__maybe_const_t<_Const,
> adjacent_transform_view>;
> > using _Base = __detail::__maybe_const_t<_Const, _Vp>;
> > + using _Fun_handle = decltype([]<size_t...
> _Ids>(std::index_sequence<_Ids...>) {
> > + return __detail::__func_handle_t<
> > + __detail::__maybe_const_t<_Const, _Fp>,
> > +
> iterator_t<__detail::__maybe_const_t<_Const || (_Ids < 0u), _Vp>>...>();
>
> Maybe '(_Ids, _Const)' would be a little less cryptic than
> '_Const || (_Ids < 0u)'?
>
Yes, that is major improvement.
> Besides that looks good!
>
> > + }(make_index_sequence<_Nm>()));
> >
> > - _Parent* _M_parent = nullptr;
> > + [[no_unique_address]] _Fun_handle _M_fun;
> > _InnerIter<_Const> _M_inner;
> >
> > + constexpr
> > + _Iterator(_Fun_handle __fun, _InnerIter<_Const> __inner)
> > + : _M_fun(__fun), _M_inner(std::move(__inner))
> > + { }
> > +
> > constexpr
> > _Iterator(_Parent& __parent, _InnerIter<_Const> __inner)
> > - : _M_parent(std::__addressof(__parent)),
> _M_inner(std::move(__inner))
> > + : _M_fun(*__parent._M_fun), _M_inner(std::move(__inner))
> > { }
> >
> > static auto
> > @@ -5854,14 +6010,14 @@ namespace views::__adaptor
> > constexpr
> > _Iterator(_Iterator<!_Const> __i)
> > requires _Const && convertible_to<_InnerIter<false>,
> _InnerIter<_Const>>
> > - : _M_parent(__i._M_parent), _M_inner(std::move(__i._M_inner))
> > + : _M_fun(__i._M_fun), _M_inner(std::move(__i._M_inner))
> > { }
> >
> > constexpr decltype(auto)
> > operator*() const
> > {
> > return std::apply([&](const auto&... __iters) -> decltype(auto) {
> > - return std::__invoke(*_M_parent->_M_fun, *__iters...);
> > + return _M_fun._M_call_deref(__iters...);
> > }, _M_inner._M_current);
> > }
> >
> > @@ -5913,7 +6069,7 @@ namespace views::__adaptor
> > operator[](difference_type __n) const requires
> random_access_range<_Base>
> > {
> > return std::apply([&](const auto&... __iters) -> decltype(auto) {
> > - return std::__invoke(*_M_parent->_M_fun, __iters[__n]...);
> > + return _M_fun._M_call_subscript(__n, __iters...);
> > }, _M_inner._M_current);
> > }
> >
> > @@ -5950,17 +6106,17 @@ namespace views::__adaptor
> > friend constexpr _Iterator
> > operator+(const _Iterator& __i, difference_type __n)
> > requires random_access_range<_Base>
> > - { return _Iterator(*__i._M_parent, __i._M_inner + __n); }
> > + { return _Iterator(__i._M_fun, __i._M_inner + __n); }
> >
> > friend constexpr _Iterator
> > operator+(difference_type __n, const _Iterator& __i)
> > requires random_access_range<_Base>
> > - { return _Iterator(*__i._M_parent, __i._M_inner + __n); }
> > + { return _Iterator(__i._M_fun, __i._M_inner + __n); }
> >
> > friend constexpr _Iterator
> > operator-(const _Iterator& __i, difference_type __n)
> > requires random_access_range<_Base>
> > - { return _Iterator(*__i._M_parent, __i._M_inner - __n); }
> > + { return _Iterator(__i._M_fun, __i._M_inner - __n); }
> >
> > friend constexpr difference_type
> > operator-(const _Iterator& __x, const _Iterator& __y)
> > diff --git
> a/libstdc++-v3/testsuite/std/ranges/adaptors/adjacent_transform/1.cc
> b/libstdc++-v3/testsuite/std/ranges/adaptors/adjacent_transform/1.cc
> > index 772e4b3b6a0..1667c6250c5 100644
> > --- a/libstdc++-v3/testsuite/std/ranges/adaptors/adjacent_transform/1.cc
> > +++ b/libstdc++-v3/testsuite/std/ranges/adaptors/adjacent_transform/1.cc
> > @@ -113,6 +113,97 @@ test04()
> > static_assert( requires { x | views::pairwise_transform(move_only{});
> } );
> > }
> >
> > +struct X
> > +{
> > + int i,j;
> > + constexpr int combine(X o) const
> > + { return i + o.j; }
> > +};
> > +
> > +template<size_t FuncSize, typename Fn>
> > +constexpr bool
> > +test05(Fn f)
> > +{
> > + using namespace __gnu_test;
> > + X x[] = {{1,500},{2,400},{3,300},{4,200},{5,100}};
> > + test_range<X, random_access_iterator_wrapper> rx(x);
> > +
> > + auto v = rx | views::pairwise_transform(f);
> > + VERIFY( ranges::size(v) == 4 );
> > + VERIFY( ranges::distance(v.begin(), v.end()) == 4 );
> > + VERIFY( ranges::equal(v, (int[]){401,302,203,104}) );
> > + VERIFY( ranges::equal(v | views::reverse, (int[]){104,203,302,401}) );
> > + using R = decltype(v);
> > + using It = ranges::iterator_t<R>;
> > + static_assert(std::same_as<int, decltype(*ranges::begin(v))>);
> > + static_assert(std::same_as<int, std::iter_value_t<It>>);
> > + static_assert(sizeof(It) == 2*sizeof(rx.begin()) + FuncSize);
> > + static_assert(ranges::view<R>);
> > + static_assert(ranges::sized_range<R>);
> > + static_assert(!ranges::common_range<R>);
> > + static_assert(ranges::random_access_range<R>);
> > + return true;
> > +}
> > +
> > +constexpr bool
> > +test05a()
> > +{
> > + auto comb = [](const X& x1, const X& x2) { return x1.i + x2.j; };
> > + return test05<sizeof(void*)>(comb);
> > +}
> > +
> > +constexpr bool
> > +test05b()
> > +{
> > + auto comb = [](const X& x1, const X& x2) static { return x1.i + x2.j;
> };
> > + return test05<0>(comb);
> > +}
> > +
> > +constexpr bool
> > +test05c()
> > +{
> > + int(*comb)(const X&, const X&) = [](const X& x1, const X& x2) {
> return x1.i + x2.j; };
> > + return test05<sizeof(void(*)())>(comb);
> > +}
> > +
> > +constexpr bool
> > +test05d()
> > +{
> > + return test05<sizeof(int(X::*)())>(&X::combine);
> > +}
> > +
> > +constexpr bool
> > +test05e()
> > +{
> > + struct PickStatic
> > + {
> > + static constexpr int
> > + operator()(const X& x1, const X& x2)
> > + { return x1.i + x2.j; }
> > +
> > + constexpr int
> > + operator()(int x, int y) const
> > + { return x + y; };
> > + };
> > + return test05<0>(PickStatic{});
> > +}
> > +
> > +constexpr bool
> > +test05f()
> > +{
> > + struct PickObject
> > + {
> > + constexpr int
> > + operator()(const X& x1, const X& x2) const
> > + { return x1.i + x2.j; }
> > +
> > + static constexpr int
> > + operator()(int x, int y)
> > + { return x + y; };
> > + };
> > + return test05<sizeof(void*)>(PickObject{});
> > +}
> > +
> > int
> > main()
> > {
> > @@ -120,4 +211,10 @@ main()
> > static_assert(test02());
> > static_assert(test03());
> > test04();
> > + static_assert(test05a());
> > + static_assert(test05b());
> > + static_assert(test05c());
> > + static_assert(test05d());
> > + static_assert(test05e());
> > + static_assert(test05f());
> > }
> > diff --git a/libstdc++-v3/testsuite/std/ranges/adaptors/transform.cc
> b/libstdc++-v3/testsuite/std/ranges/adaptors/transform.cc
> > index 1788db1ce8d..c6d6b916730 100644
> > --- a/libstdc++-v3/testsuite/std/ranges/adaptors/transform.cc
> > +++ b/libstdc++-v3/testsuite/std/ranges/adaptors/transform.cc
> > @@ -28,12 +28,12 @@ using __gnu_test::random_access_iterator_wrapper;
> > namespace ranges = std::ranges;
> > namespace views = std::ranges::views;
> >
> > +template<typename Fn>
> > void
> > -test01()
> > +test01(Fn f)
> > {
> > int x[] = {1,2,3,4,5};
> > - auto is_odd = [] (int i) { return i%2==1; };
> > - auto v = x | views::transform(is_odd);
> > + auto v = x | views::transform(f);
> > VERIFY( ranges::equal(v, (int[]){1,0,1,0,1}) );
> > using R = decltype(v);
> > static_assert(std::same_as<bool, decltype(*ranges::begin(v))>);
> > @@ -42,30 +42,124 @@ test01()
> > static_assert(ranges::random_access_range<R>);
> > }
> >
> > +void
> > +test01a()
> > +{
> > + auto is_odd = [] (int i) { return i%2==1; };
> > + test01(is_odd);
> > +}
> > +
> > +void
> > +test01b()
> > +{
> > +#if __cpp_static_call_operator >= 202207L
> > + auto is_odd = [] (int i) static { return i%2==1; };
> > + test01(is_odd);
> > +#endif
> > +}
> > +
> > +void
> > +test01c()
> > +{
> > + bool(*is_odd)(int) = [] (int i) { return i%2==1; };
> > + test01(is_odd);
> > +}
> > +
> > struct X
> > {
> > int i,j;
> > + int& first() { return i; }
> > };
> >
> > +template<size_t FuncSize, typename Fn>
> > void
> > -test02()
> > +test02(Fn f)
> > {
> > X x[] = {{1,2},{3,4},{5,6},{7,8},{9,10}};
> > test_range<X, random_access_iterator_wrapper> rx(x);
> > - auto v = rx | views::transform(&X::i);
> > + auto v = rx | views::transform(f);
> > VERIFY( ranges::size(v) == 5 );
> > VERIFY( ranges::distance(v.begin(), v.end()) == 5 );
> > VERIFY( ranges::equal(v, (int[]){1,3,5,7,9}) );
> > VERIFY( ranges::equal(v | views::reverse, (int[]){9,7,5,3,1}) );
> > using R = decltype(v);
> > + using It = ranges::iterator_t<R>;
> > static_assert(std::same_as<int&, decltype(*ranges::begin(v))>);
> > - static_assert(std::same_as<int,
> std::iter_value_t<ranges::iterator_t<R>>>);
> > + static_assert(std::same_as<int, std::iter_value_t<It>>);
> > + static_assert(sizeof(It) == sizeof(rx.begin()) + FuncSize);
> > static_assert(ranges::view<R>);
> > static_assert(ranges::sized_range<R>);
> > static_assert(!ranges::common_range<R>);
> > static_assert(ranges::random_access_range<R>);
> > }
> >
> > +void
> > +test02a()
> > +{ test02<sizeof(int X::*)>(&X::i); }
> > +
> > +void
> > +test02b()
> > +{ test02<sizeof(int(X::*)())>(&X::first); }
> > +
> > +void
> > +test02c()
> > +{
> > + auto first = [](X& x) -> int& { return x.i; };
> > + test02<sizeof(void*)>(first);
> > +}
> > +
> > +void
> > +test02d()
> > +{
> > +#if __cpp_static_call_operator >= 202207L
> > + auto first = [](X& x) static -> int& { return x.i; };
> > + test02<0>(first);
> > +#endif
> > +}
> > +
> > +void
> > +test02e()
> > +{
> > + int&(*fptr)(X&) = [](X& x) -> int& { return x.i; };
> > + test02<sizeof(void(*)())>(fptr);
> > +}
> > +
> > +void
> > +test02f()
> > +{
> > +#if __cpp_static_call_operator >= 202207L
> > + struct PickStatic
> > + {
> > + static constexpr int&
> > + operator()(X& x)
> > + { return x.i; }
> > +
> > + constexpr int
> > + operator()(char*) const
> > + { return 0; };
> > + };
> > + test02<0>(PickStatic{});
> > +#endif
> > +}
> > +
> > +void
> > +test02g()
> > +{
> > +#if __cpp_static_call_operator >= 202207L
> > + struct PickObject
> > + {
> > + constexpr int&
> > + operator()(X& x) const
> > + { return x.i; }
> > +
> > + static constexpr int
> > + operator()(char*)
> > + { return 0; };
> > + };
> > + test02<sizeof(void*)>(PickObject{});
> > +#endif
> > +}
> > +
> > void
> > test03()
> > {
> > @@ -230,8 +324,16 @@ test11()
> > int
> > main()
> > {
> > - test01();
> > - test02();
> > + test01a();
> > + test01b();
> > + test01c();
> > + test02a();
> > + test02b();
> > + test02c();
> > + test02d();
> > + test02e();
> > + test02f();
> > + test02g();
> > test03();
> > test04();
> > test05();
> > diff --git a/libstdc++-v3/testsuite/std/ranges/zip_transform/1.cc
> b/libstdc++-v3/testsuite/std/ranges/zip_transform/1.cc
> > index 9a0ad3814e6..d4bd7db26cb 100644
> > --- a/libstdc++-v3/testsuite/std/ranges/zip_transform/1.cc
> > +++ b/libstdc++-v3/testsuite/std/ranges/zip_transform/1.cc
> > @@ -132,6 +132,97 @@ test04()
> > static_assert( requires { views::zip_transform(move_only{}, x, x); }
> );
> > }
> >
> > +struct X
> > +{
> > + int i;
> > + constexpr int add(int b) const
> > + { return i+b; }
> > +};
> > +
> > +template<size_t ExtraSize, typename Fn>
> > +constexpr bool
> > +test05(Fn f)
> > +{
> > + using namespace __gnu_test;
> > + X x[] = {{1},{2},{3},{4},{5}};
> > + int y[] = {500,400,300,200,100};
> > + test_range<X, random_access_iterator_wrapper> rx(x);
> > + test_range<int, random_access_iterator_wrapper> ry(y);
> > +
> > + auto v = views::zip_transform(f, rx, ry);
> > + VERIFY( ranges::size(v) == 5 );
> > + VERIFY( ranges::distance(v.begin(), v.end()) == 5 );
> > + VERIFY( ranges::equal(v, (int[]){501,402,303,204,105}) );
> > + VERIFY( ranges::equal(v | views::reverse,
> (int[]){105,204,303,402,501}) );
> > + using R = decltype(v);
> > + using It = ranges::iterator_t<R>;
> > + static_assert(std::same_as<int, decltype(*ranges::begin(v))>);
> > + static_assert(std::same_as<int, std::iter_value_t<It>>);
> > + static_assert(sizeof(It) == sizeof(rx.begin()) + sizeof(ry.begin()) +
> ExtraSize);
> > + static_assert(ranges::view<R>);
> > + static_assert(ranges::sized_range<R>);
> > + static_assert(ranges::common_range<R>);
> > + static_assert(ranges::random_access_range<R>);
> > + return true;
> > +}
> > +
> > +constexpr bool
> > +test05a()
> > +{
> > + auto add = [](const X& x, int v) { return x.i + v; };
> > + return test05<sizeof(void*)>(add);
> > +}
> > +
> > +constexpr bool
> > +test05b()
> > +{
> > + auto add = [](const X& x, int v) static { return x.i + v; };
> > + return test05<0>(add);
> > +}
> > +
> > +constexpr bool
> > +test05c()
> > +{
> > + int(*ptr)(const X&, int) = [](const X& x, int v) { return x.i + v; };
> > + return test05<sizeof(void(*)())>(ptr);
> > +}
> > +
> > +constexpr bool
> > +test05d()
> > +{ return test05<sizeof(int(X::*)())>(&X::add); }
> > +
> > +constexpr bool
> > +test05e()
> > +{
> > + struct PickStatic
> > + {
> > + static constexpr int
> > + operator()(const X& x1, int v)
> > + { return x1.i + v; }
> > +
> > + constexpr int
> > + operator()(int x, int y) const
> > + { return x + y; };
> > + };
> > + return test05<0>(PickStatic{});
> > +}
> > +
> > +constexpr bool
> > +test05f()
> > +{
> > + struct PickObject
> > + {
> > + constexpr int
> > + operator()(const X& x1, int v) const
> > + { return x1.i + v; }
> > +
> > + static constexpr int
> > + operator()(int x, int y)
> > + { return x + y; };
> > + };
> > + return test05<sizeof(void*)>(PickObject{});
> > +}
> > +
> > int
> > main()
> > {
> > @@ -139,4 +230,14 @@ main()
> > static_assert(test02());
> > static_assert(test03());
> > test04();
> > + static_assert(test01());
> > + static_assert(test02());
> > + static_assert(test03());
> > + test04();
> > + static_assert(test05a());
> > + static_assert(test05b());
> > + static_assert(test05c());
> > + static_assert(test05d());
> > + static_assert(test05e());
> > + static_assert(test05f());
> > }
> > --
> > 2.51.0
> >
> >
