> 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.
This is a very good observation, so recreating empty objects is still
problematic.
It also seems to suggest that
https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2024/p3117r1.html (most
likely a follow-up to this patch) and
https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2025/p3705r1.html might
have issues with this.
For example, `operator()` uses `this` or `operator==` uses `this`.
Tomasz Kaminski <[email protected]> 於 2025年11月14日 週五 下午2:36寫道：
>
>
> 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
>> >
>> >
>
>
