diff --git a/stl/inc/ranges b/stl/inc/ranges index 3f8a7cc415..3f8faa137e 100644 --- a/stl/inc/ranges +++ b/stl/inc/ranges @@ -1523,8 +1523,10 @@ namespace ranges { constexpr auto _Compile_time_max_size> = _Compile_time_max_size; namespace views { + // direct-non-list-initialization is specified in the Standard (N4981 [range.as.rvalue.overview]/2.2) + // and needed for EDG, DevCom-10698021 template - concept _Can_as_rvalue = requires(_Rng&& __r) { as_rvalue_view{static_cast<_Rng&&>(__r)}; }; + concept _Can_as_rvalue = requires(_Rng&& __r) { as_rvalue_view(static_cast<_Rng&&>(__r)); }; class _As_rvalue_fn : public _Pipe::_Base<_As_rvalue_fn> { private: @@ -1532,10 +1534,10 @@ namespace ranges { template _NODISCARD static consteval _Choice_t<_St> _Choose() noexcept { - if constexpr (same_as, range_reference_t<_Rng>>) { + if constexpr (input_range<_Rng> && same_as, range_reference_t<_Rng>>) { return {_St::_All, noexcept(views::all(_STD declval<_Rng>()))}; } else if constexpr (_Can_as_rvalue<_Rng>) { - return {_St::_As_rvalue, noexcept(as_rvalue_view{_STD declval<_Rng>()})}; + return {_St::_As_rvalue, noexcept(as_rvalue_view(_STD declval<_Rng>()))}; } else { return {_St::_None}; } @@ -1553,7 +1555,7 @@ namespace ranges { if constexpr (_Strat == _St::_All) { return views::all(_STD forward<_Rng>(_Range)); } else if constexpr (_Strat == _St::_As_rvalue) { - return as_rvalue_view{_STD forward<_Rng>(_Range)}; + return as_rvalue_view(_STD forward<_Rng>(_Range)); } else { _STL_INTERNAL_STATIC_ASSERT(false); // unexpected strategy } diff --git a/tests/std/tests/P2446R2_views_as_rvalue/test.cpp b/tests/std/tests/P2446R2_views_as_rvalue/test.cpp index 0a68c5d890..3668e8341d 100644 --- a/tests/std/tests/P2446R2_views_as_rvalue/test.cpp +++ b/tests/std/tests/P2446R2_views_as_rvalue/test.cpp @@ -401,6 +401,17 @@ void test_example_from_p2446r2() { assert(ranges::all_of(words, ranges::empty)); // all strings from words are empty (implementation assumption) } +// LWG-4083 "views::as_rvalue should reject non-input ranges" +struct OutputRvalueIterator { + using difference_type = int; + int operator*() const; + OutputRvalueIterator& operator++(); + void operator++(int); +}; +using OutputRvalueRange = decltype(ranges::subrange{OutputRvalueIterator{}, unreachable_sentinel}); + +static_assert(!CanViewAsRvalue); + int main() { { // Validate views // ... copyable