diff --git a/libcxx/docs/Status/Cxx20Issues.csv b/libcxx/docs/Status/Cxx20Issues.csv
--- a/libcxx/docs/Status/Cxx20Issues.csv
+++ b/libcxx/docs/Status/Cxx20Issues.csv
@@ -296,6 +296,6 @@
"`3393 <https://wg21.link/LWG3393>`__","Missing/incorrect feature test macro for coroutines","Prague","|Complete|","14.0"
"`3395 <https://wg21.link/LWG3395>`__","Definition for three-way comparison needs to be updated (US 152)","Prague","","","|spaceship|"
"`3396 <https://wg21.link/LWG3396>`__","Clarify point of reference for ``source_location::current()``\ (DE 169)","Prague","",""
-"`3397 <https://wg21.link/LWG3397>`__","``ranges::basic_istream_view::iterator``\ should not provide ``iterator_category``\ ","Prague","","","|ranges|"
+"`3397 <https://wg21.link/LWG3397>`__","``ranges::basic_istream_view::iterator``\ should not provide ``iterator_category``\ ","Prague","|Complete|","16.0","|ranges|"
"`3398 <https://wg21.link/LWG3398>`__","``tuple_element_t``\ is also wrong for ``const subrange``\ ","Prague","|Complete|","14.0","|ranges|"
"`3446 <https://wg21.link/LWG3446>`__","``indirectly_readable_traits``\ ambiguity for types with both ``value_type``\ and ``element_type``\ ","November virtual meeting","|Complete|","13.0"
diff --git a/libcxx/docs/Status/Cxx20Papers.csv b/libcxx/docs/Status/Cxx20Papers.csv
--- a/libcxx/docs/Status/Cxx20Papers.csv
+++ b/libcxx/docs/Status/Cxx20Papers.csv
@@ -108,7 +108,7 @@
"`P0784R7 <https://wg21.link/P0784R7>`__","CWG","More constexpr containers","Cologne","|Complete|","12.0"
"`P0980R1 <https://wg21.link/P0980R1>`__","LWG","Making std::string constexpr","Cologne","|Complete|","15.0"
"`P1004R2 <https://wg21.link/P1004R2>`__","LWG","Making std::vector constexpr","Cologne","|Complete|","15.0"
-"`P1035R7 <https://wg21.link/P1035R7>`__","LWG","Input Range Adaptors","Cologne","",""
+"`P1035R7 <https://wg21.link/P1035R7>`__","LWG","Input Range Adaptors","Cologne","|In Progress|","16.0"
"`P1065R2 <https://wg21.link/P1065R2>`__","LWG","Constexpr INVOKE","Cologne","|Complete|","12.0"
"`P1135R6 <https://wg21.link/P1135R6>`__","LWG","The C++20 Synchronization Library","Cologne","|Complete|","11.0"
"`P1207R4 <https://wg21.link/P1207R4>`__","LWG","Movability of Single-pass Iterators","Cologne","|Complete|","15.0"
@@ -124,7 +124,7 @@
"`P1523R1 <https://wg21.link/P1523R1>`__","LWG","Views and Size Types","Cologne","|Complete|","15.0"
"`P1612R1 <https://wg21.link/P1612R1>`__","LWG","Relocate Endian's Specification","Cologne","|Complete|","10.0"
"`P1614R2 <https://wg21.link/P1614R2>`__","LWG","The Mothership has Landed","Cologne","|In Progress|",""
-"`P1638R1 <https://wg21.link/P1638R1>`__","LWG","basic_istream_view::iterator should not be copyable","Cologne","",""
+"`P1638R1 <https://wg21.link/P1638R1>`__","LWG","basic_istream_view::iterator should not be copyable","Cologne","|Complete|","16.0"
"`P1643R1 <https://wg21.link/P1643R1>`__","LWG","Add wait/notify to atomic_ref","Cologne","",""
"`P1644R0 <https://wg21.link/P1644R0>`__","LWG","Add wait/notify to atomic<shared_ptr>","Cologne","",""
"`P1650R0 <https://wg21.link/P1650R0>`__","LWG","Output std::chrono::days with 'd' suffix","Cologne","",""
diff --git a/libcxx/docs/Status/Cxx2bIssues.csv b/libcxx/docs/Status/Cxx2bIssues.csv
--- a/libcxx/docs/Status/Cxx2bIssues.csv
+++ b/libcxx/docs/Status/Cxx2bIssues.csv
@@ -121,7 +121,7 @@
`3563 <https://wg21.link/LWG3563>`__,"``keys_view`` example is broken","October 2021","","","|ranges|"
`3566 <https://wg21.link/LWG3566>`__,"Constraint recursion for ``operator<=>(optional<T>, U)``","October 2021","","","|spaceship|"
`3567 <https://wg21.link/LWG3567>`__,"Formatting move-only iterators take two","October 2021","","","|format|"
-`3568 <https://wg21.link/LWG3568>`__,"``basic_istream_view`` needs to initialize ``value_``","October 2021","","","|ranges|"
+`3568 <https://wg21.link/LWG3568>`__,"``basic_istream_view`` needs to initialize ``value_``","October 2021","|Complete|","16.0","|ranges|"
`3570 <https://wg21.link/LWG3570>`__,"``basic_osyncstream::emit`` should be an unformatted output function","October 2021","",""
`3571 <https://wg21.link/LWG3571>`__,"``flush_emit`` should set ``badbit`` if the ``emit`` call fails","October 2021","",""
`3572 <https://wg21.link/LWG3572>`__,"``copyable-box`` should be fully ``constexpr``","October 2021","|Complete|","14.0","|ranges|"
diff --git a/libcxx/docs/Status/RangesIssues.csv b/libcxx/docs/Status/RangesIssues.csv
--- a/libcxx/docs/Status/RangesIssues.csv
+++ b/libcxx/docs/Status/RangesIssues.csv
@@ -1,6 +1,6 @@
"Number","Name","Status","First released version"
`P0896R4 <https://wg21.link/P0896R4>`__,<ranges>,|Complete|,15.0
-`P1035R7 <https://wg21.link/P1035R7>`__,Input Range Adaptors,,
+`P1035R7 <https://wg21.link/P1035R7>`__,Input Range Adaptors,|In Progress|,16.0
`P1207R4 <https://wg21.link/P1207R4>`__,Movability Of Single-Pass Iterators,|Complete|,15.0
`P1243R4 <https://wg21.link/P1243R4>`__,Rangify New Algorithms,|Complete|,15.0
`P1248R1 <https://wg21.link/P1248R1>`__,Fixing Relations,|Complete|,13.0
@@ -10,7 +10,7 @@
`P1474R1 <https://wg21.link/P1474R1>`__,Helpful Pointers For contiguous_iterator,|Complete|,15.0
`P1522R1 <https://wg21.link/P1522R1>`__,Iterator Difference Type And Integer Overflow,|Complete|,15.0
`P1523R1 <https://wg21.link/P1523R1>`__,Views And Size Types,|Complete|,15.0
-`P1638R1 <https://wg21.link/P1638R1>`__,basic_istream_view::iterator Should Not Be Copyable,,
+`P1638R1 <https://wg21.link/P1638R1>`__,basic_istream_view::iterator Should Not Be Copyable,|Complete|,16.0
`P1716R3 <https://wg21.link/P1716R3>`__,Range Comparison Algorithms Are Over-Constrained,|Complete|,15.0
`P1739R4 <https://wg21.link/P1739R4>`__,Avoiding Template Bloat For Ranges,|Complete|,15.0
`P1862R1 <https://wg21.link/P1862R1>`__,Range Adaptors For Non-Copyable Iterators,,
diff --git a/libcxx/include/CMakeLists.txt b/libcxx/include/CMakeLists.txt
--- a/libcxx/include/CMakeLists.txt
+++ b/libcxx/include/CMakeLists.txt
@@ -467,6 +467,7 @@
__ranges/enable_view.h
__ranges/filter_view.h
__ranges/iota_view.h
+ __ranges/istream_view.h
__ranges/join_view.h
__ranges/lazy_split_view.h
__ranges/non_propagating_cache.h
diff --git a/libcxx/include/__ranges/istream_view.h b/libcxx/include/__ranges/istream_view.h
new file mode 100644
--- /dev/null
+++ b/libcxx/include/__ranges/istream_view.h
@@ -0,0 +1,132 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#ifndef _LIBCPP___RANGES_ISTREAM_VIEW_H
+#define _LIBCPP___RANGES_ISTREAM_VIEW_H
+
+#include <__concepts/constructible.h>
+#include <__concepts/derived_from.h>
+#include <__concepts/movable.h>
+#include <__config>
+#include <__iterator/default_sentinel.h>
+#include <__iterator/iterator_traits.h>
+#include <__memory/addressof.h>
+#include <__ranges/view_interface.h>
+#include <__string/char_traits.h>
+#include <__type_traits/remove_cvref.h>
+#include <__utility/forward.h>
+#include <istream>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+# pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17
+
+namespace ranges {
+
+template <class _Val, class _CharT, class _Traits>
+concept __stream_extractable = requires(basic_istream<_CharT, _Traits>& __is, _Val& __t) { __is >> __t; };
+
+template <movable _Val, class _CharT, class _Traits = char_traits<_CharT>>
+ requires default_initializable<_Val> && __stream_extractable<_Val, _CharT, _Traits>
+class basic_istream_view : public view_interface<basic_istream_view<_Val, _CharT, _Traits>> {
+public:
+ constexpr explicit basic_istream_view(basic_istream<_CharT, _Traits>& __stream)
+ : __stream_(std::addressof(__stream)) {}
+
+ constexpr auto begin() {
+ *__stream_ >> __value_;
+ return __iterator{*this};
+ }
+
+ constexpr default_sentinel_t end() const noexcept { return default_sentinel; }
+
+private:
+ class __iterator;
+
+ basic_istream<_CharT, _Traits>* __stream_;
+ _Val __value_ = _Val();
+};
+
+template <movable _Val, class _CharT, class _Traits>
+ requires default_initializable<_Val> && __stream_extractable<_Val, _CharT, _Traits>
+class basic_istream_view<_Val, _CharT, _Traits>::__iterator {
+public:
+ using iterator_concept = input_iterator_tag;
+ using difference_type = ptrdiff_t;
+ using value_type = _Val;
+
+ constexpr explicit __iterator(basic_istream_view& __parent) noexcept : __parent_(std::addressof(__parent)) {}
+
+ __iterator(const __iterator&) = delete;
+ __iterator(__iterator&&) = default;
+
+ __iterator& operator=(const __iterator&) = delete;
+ __iterator& operator=(__iterator&&) = default;
+
+ __iterator& operator++() {
+ *__parent_->__stream_ >> __parent_->__value_;
+ return *this;
+ }
+
+ void operator++(int) { ++*this; }
+
+ _Val& operator*() const { return __parent_->__value_; }
+
+ friend bool operator==(const __iterator& __x, default_sentinel_t) { return !*__x.__get_parent_stream(); }
+
+private:
+ basic_istream_view* __parent_;
+
+ constexpr basic_istream<_CharT, _Traits>* __get_parent_stream() const { return __parent_->__stream_; }
+};
+
+template <class _Val>
+using istream_view = basic_istream_view<_Val, char>;
+
+template <class _Val>
+using wistream_view = basic_istream_view<_Val, wchar_t>;
+
+namespace views {
+namespace __istream {
+
+// clang-format off
+template <class _Tp>
+struct __fn {
+ template <class _Up, class _UnCVRef = remove_cvref_t<_Up>>
+ requires derived_from<_UnCVRef, basic_istream<typename _UnCVRef::char_type,
+ typename _UnCVRef::traits_type>>
+ auto operator()(_Up&& __u) const
+ noexcept(noexcept(basic_istream_view<_Tp, typename _UnCVRef::char_type,
+ typename _UnCVRef::traits_type>(std::forward<_Up>(__u))))
+ -> decltype( basic_istream_view<_Tp, typename _UnCVRef::char_type,
+ typename _UnCVRef::traits_type>(std::forward<_Up>(__u)))
+ { return basic_istream_view<_Tp, typename _UnCVRef::char_type,
+ typename _UnCVRef::traits_type>(std::forward<_Up>(__u));
+ }
+};
+// clang-format on
+
+} // namespace __istream
+
+inline namespace __cpo {
+template <class _Tp>
+inline constexpr auto istream = __istream::__fn<_Tp>{};
+} // namespace __cpo
+} // namespace views
+
+} // namespace ranges
+
+#endif // _LIBCPP_STD_VER > 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___RANGES_ISTREAM_VIEW_H
diff --git a/libcxx/include/module.modulemap.in b/libcxx/include/module.modulemap.in
--- a/libcxx/include/module.modulemap.in
+++ b/libcxx/include/module.modulemap.in
@@ -980,6 +980,7 @@
module enable_view { private header "__ranges/enable_view.h" }
module filter_view { private header "__ranges/filter_view.h" }
module iota_view { private header "__ranges/iota_view.h" }
+ module istream_view { private header "__ranges/istream_view.h" }
module join_view { private header "__ranges/join_view.h" }
module lazy_split_view { private header "__ranges/lazy_split_view.h" }
module non_propagating_cache { private header "__ranges/non_propagating_cache.h" }
diff --git a/libcxx/include/ranges b/libcxx/include/ranges
--- a/libcxx/include/ranges
+++ b/libcxx/include/ranges
@@ -228,6 +228,19 @@
inline constexpr unspecified lazy_split = unspecified;
}
+ // [range.istream], istream view
+ template<movable Val, class CharT, class Traits = char_traits<CharT>>
+ requires see below
+ class basic_istream_view;
+
+ template<class Val>
+ using istream_view = basic_istream_view<Val, char>;
+
+ template<class Val>
+ using wistream_view = basic_istream_view<Val, wchar_t>;
+
+ namespace views { template<class T> inline constexpr unspecified istream = unspecified; }
+
// [range.zip], zip view
template<input_range... Views>
requires (view<Views> && ...) && (sizeof...(Views) > 0)
@@ -288,6 +301,7 @@
#include <__ranges/enable_view.h>
#include <__ranges/filter_view.h>
#include <__ranges/iota_view.h>
+#include <__ranges/istream_view.h>
#include <__ranges/join_view.h>
#include <__ranges/lazy_split_view.h>
#include <__ranges/rbegin.h>
diff --git a/libcxx/test/libcxx/private_headers.verify.cpp b/libcxx/test/libcxx/private_headers.verify.cpp
--- a/libcxx/test/libcxx/private_headers.verify.cpp
+++ b/libcxx/test/libcxx/private_headers.verify.cpp
@@ -498,6 +498,7 @@
#include <__ranges/enable_view.h> // expected-error@*:* {{use of private header from outside its module: '__ranges/enable_view.h'}}
#include <__ranges/filter_view.h> // expected-error@*:* {{use of private header from outside its module: '__ranges/filter_view.h'}}
#include <__ranges/iota_view.h> // expected-error@*:* {{use of private header from outside its module: '__ranges/iota_view.h'}}
+#include <__ranges/istream_view.h> // expected-error@*:* {{use of private header from outside its module: '__ranges/istream_view.h'}}
#include <__ranges/join_view.h> // expected-error@*:* {{use of private header from outside its module: '__ranges/join_view.h'}}
#include <__ranges/lazy_split_view.h> // expected-error@*:* {{use of private header from outside its module: '__ranges/lazy_split_view.h'}}
#include <__ranges/non_propagating_cache.h> // expected-error@*:* {{use of private header from outside its module: '__ranges/non_propagating_cache.h'}}
diff --git a/libcxx/test/std/ranges/range.factories/range.istream.view/begin.pass.cpp b/libcxx/test/std/ranges/range.factories/range.istream.view/begin.pass.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/std/ranges/range.factories/range.istream.view/begin.pass.cpp
@@ -0,0 +1,42 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+// constexpr auto begin();
+
+#include <ranges>
+
+#include <cassert>
+#include <sstream>
+
+template <class T>
+concept HasBegin = requires(T t) { t.begin(); };
+
+static_assert(HasBegin<std::ranges::istream_view<int>>);
+static_assert(!HasBegin<const std::ranges::istream_view<int>>);
+
+int main(int, char**) {
+ // begin should read the first element
+ {
+ std::istringstream iss{"12 3"};
+ std::ranges::istream_view<int> isv{iss};
+ auto it = isv.begin();
+ assert(*it == 12);
+ }
+
+ // empty stream
+ {
+ std::istringstream iss{""};
+ std::ranges::istream_view<int> isv{iss};
+ auto it = isv.begin();
+ assert(it == isv.end());
+ }
+
+ return 0;
+}
diff --git a/libcxx/test/std/ranges/range.factories/range.istream.view/cpo.pass.cpp b/libcxx/test/std/ranges/range.factories/range.istream.view/cpo.pass.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/std/ranges/range.factories/range.istream.view/cpo.pass.cpp
@@ -0,0 +1,31 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+// std::views::istream<T>
+
+#include <ranges>
+#include <sstream>
+
+#include <cassert>
+
+static_assert(!std::is_invocable_v<decltype((std::views::istream<int>))>);
+static_assert(std::is_invocable_v<decltype((std::views::istream<int>)), std::istream&>);
+static_assert(!std::is_invocable_v<decltype((std::views::istream<int>)), const std::istream&>);
+static_assert(!std::is_invocable_v<decltype((std::views::istream<int>)), int>);
+
+int main(int, char**) {
+ {
+ std::istringstream iss{"12 3"};
+ auto isv = std::views::istream<int>(iss);
+ auto it = isv.begin();
+ assert(*it == 12);
+ }
+ return 0;
+}
diff --git a/libcxx/test/std/ranges/range.factories/range.istream.view/ctor.pass.cpp b/libcxx/test/std/ranges/range.factories/range.istream.view/ctor.pass.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/std/ranges/range.factories/range.istream.view/ctor.pass.cpp
@@ -0,0 +1,41 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+// constexpr explicit basic_istream_view(basic_istream<CharT, Traits>& stream);
+
+#include <ranges>
+
+#include <cassert>
+#include <sstream>
+
+// test that the constructor is explicit
+static_assert(std::constructible_from<std::ranges::istream_view<int>, std::istream&>);
+static_assert(!std::convertible_to<std::istream&, std::ranges::istream_view<int>>);
+
+int main(int, char**) {
+ // test constructor init the stream pointer to the passed one
+ {
+ std::istringstream iss{"123"};
+ std::ranges::istream_view<int> isv{iss};
+ auto it = isv.begin();
+ assert(*it == 123);
+ }
+
+ // LWG 3568. basic_istream_view needs to initialize value_
+ {
+ std::istringstream iss{"123"};
+ std::ranges::istream_view<int> isv{iss};
+ using Iter = std::ranges::iterator_t<decltype(isv)>;
+ Iter iter{isv};
+ assert(*iter == 0);
+ }
+
+ return 0;
+}
diff --git a/libcxx/test/std/ranges/range.factories/range.istream.view/end.pass.cpp b/libcxx/test/std/ranges/range.factories/range.istream.view/end.pass.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/std/ranges/range.factories/range.istream.view/end.pass.cpp
@@ -0,0 +1,40 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+// constexpr default_sentinel_t end() const noexcept;
+
+#include <ranges>
+
+#include <cassert>
+#include <sstream>
+
+template <class T>
+concept HasEnd = requires(T t) { t.end(); };
+
+template <class T>
+concept NoexceptEnd =
+ requires(T t) {
+ { t.end() } noexcept;
+ };
+
+static_assert(HasEnd<std::ranges::istream_view<int>>);
+static_assert(HasEnd<const std::ranges::istream_view<int>>);
+
+static_assert(NoexceptEnd<std::ranges::istream_view<int>>);
+static_assert(NoexceptEnd<const std::ranges::istream_view<int>>);
+
+int main(int, char**) {
+ {
+ std::istringstream iss{"12"};
+ std::ranges::istream_view<int> isv{iss};
+ [[maybe_unused]] std::same_as<std::default_sentinel_t> auto sent = isv.end();
+ }
+ return 0;
+}
diff --git a/libcxx/test/std/ranges/range.factories/range.istream.view/general.pass.cpp b/libcxx/test/std/ranges/range.factories/range.istream.view/general.pass.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/std/ranges/range.factories/range.istream.view/general.pass.cpp
@@ -0,0 +1,28 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+// Some basic examples of how istream_view might be used in the wild. This is a general
+// collection of sample algorithms and functions that try to mock general usage of
+// this view.
+
+#include <algorithm>
+#include <cassert>
+#include <ranges>
+#include <sstream>
+
+int main(int, const char**) {
+ {
+ auto ints = std::istringstream{"0 1 2 3 4"};
+ auto oss = std::ostringstream{};
+ std::ranges::copy(std::ranges::istream_view<int>(ints), std::ostream_iterator<int>{oss, "-"});
+ assert(oss.str() == "0-1-2-3-4-");
+ }
+ return 0;
+}
diff --git a/libcxx/test/std/ranges/range.factories/range.istream.view/iterator/compare.pass.cpp b/libcxx/test/std/ranges/range.factories/range.istream.view/iterator/compare.pass.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/std/ranges/range.factories/range.istream.view/iterator/compare.pass.cpp
@@ -0,0 +1,46 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+// friend bool operator==(const iterator& x, default_sentinel_t);
+
+#include <ranges>
+
+#include <cassert>
+#include <sstream>
+
+int main(int, char**) {
+ // fail to read
+ {
+ std::istringstream iss{"a123 4"};
+ std::ranges::istream_view<int> isv{iss};
+ auto it = isv.begin();
+ assert(it == std::default_sentinel);
+ }
+
+ // iterate through the end
+ {
+ std::istringstream iss{"123 "};
+ std::ranges::istream_view<int> isv{iss};
+ auto it = isv.begin();
+ assert(it != std::default_sentinel);
+ ++it;
+ assert(it == std::default_sentinel);
+ }
+
+ // empty stream
+ {
+ std::istringstream iss{""};
+ std::ranges::istream_view<int> isv{iss};
+ auto it = isv.begin();
+ assert(it == std::default_sentinel);
+ }
+
+ return 0;
+}
diff --git a/libcxx/test/std/ranges/range.factories/range.istream.view/iterator/ctor.pass.cpp b/libcxx/test/std/ranges/range.factories/range.istream.view/iterator/ctor.pass.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/std/ranges/range.factories/range.istream.view/iterator/ctor.pass.cpp
@@ -0,0 +1,36 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+// constexpr explicit iterator(basic_istream_view& parent) noexcept;
+
+#include <ranges>
+
+#include <cassert>
+#include <sstream>
+
+// test that the constructor is explicit
+using IstreamView = std::ranges::istream_view<int>;
+using Iter = std::ranges::iterator_t<IstreamView>;
+static_assert(std::constructible_from<Iter, IstreamView&>);
+static_assert(!std::convertible_to<IstreamView&, Iter>);
+
+// test that the constructor is noexcept
+static_assert(std::is_nothrow_constructible_v<Iter, IstreamView&>);
+
+int main(int, char**) {
+ {
+ std::istringstream iss{"123"};
+ std::ranges::istream_view<int> isv{iss};
+ Iter it{isv};
+ ++it;
+ assert(*it == 123);
+ }
+ return 0;
+}
diff --git a/libcxx/test/std/ranges/range.factories/range.istream.view/iterator/deref.pass.cpp b/libcxx/test/std/ranges/range.factories/range.istream.view/iterator/deref.pass.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/std/ranges/range.factories/range.istream.view/iterator/deref.pass.cpp
@@ -0,0 +1,38 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+// Val& operator*() const;
+
+#include <ranges>
+
+#include <cassert>
+#include <sstream>
+
+int main(int, char**) {
+ // operator* should return correct value
+ {
+ std::istringstream iss{"1 2 345 "};
+ std::ranges::istream_view<int> isv{iss};
+ auto it = isv.begin();
+ std::same_as<int&> decltype(auto) v1 = *it;
+ assert(v1 == 1);
+ }
+
+ // operator* should return the same reference to the value stored in the view
+ {
+ std::istringstream iss{"1 2 345 "};
+ std::ranges::istream_view<int> isv{iss};
+ using Iter = std::ranges::iterator_t<decltype(isv)>;
+
+ Iter it1{isv};
+ Iter it2{isv};
+ assert(&*it1 == &*it2);
+ }
+}
\ No newline at end of file
diff --git a/libcxx/test/std/ranges/range.factories/range.istream.view/iterator/increment.pass.cpp b/libcxx/test/std/ranges/range.factories/range.istream.view/iterator/increment.pass.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/std/ranges/range.factories/range.istream.view/iterator/increment.pass.cpp
@@ -0,0 +1,49 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+// iterator& operator++();
+// void operator++(int);
+
+#include <ranges>
+
+#include <cassert>
+#include <sstream>
+
+int main(int, char**) {
+ // operator ++()
+ {
+ std::istringstream iss{"1 2 345 "};
+ std::ranges::istream_view<int> isv{iss};
+ auto it = isv.begin();
+ assert(*it == 1);
+
+ std::same_as<decltype(it)&> decltype(auto) it2 = ++it;
+ assert(&it2 == &it);
+ assert(*it2 == 2);
+
+ ++it2;
+ assert(*it2 == 345);
+
+ ++it2;
+ assert(it2 == isv.end());
+ }
+
+ // operator ++(int)
+ {
+ std::istringstream iss{"1 2 345 "};
+ std::ranges::istream_view<int> isv{iss};
+ auto it = isv.begin();
+ assert(*it == 1);
+
+ static_assert(std::same_as<decltype(it++), void>);
+ it++;
+ assert(*it == 2);
+ }
+}
diff --git a/libcxx/test/std/ranges/range.factories/range.istream.view/iterator/member_types.compile.pass.cpp b/libcxx/test/std/ranges/range.factories/range.istream.view/iterator/member_types.compile.pass.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/std/ranges/range.factories/range.istream.view/iterator/member_types.compile.pass.cpp
@@ -0,0 +1,32 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+// Member typedefs in istream_view<T>::<iterator>.
+
+#include <ranges>
+
+template <class T>
+concept HasIterCategory = requires { typename T::iterator_category; };
+
+template <class Val>
+void test() {
+ using Iter = std::ranges::iterator_t<std::ranges::istream_view<Val>>;
+ static_assert(std::is_same_v<typename Iter::iterator_concept, std::input_iterator_tag>);
+ static_assert(std::is_same_v<typename Iter::difference_type, std::ptrdiff_t>);
+ static_assert(std::is_same_v<typename Iter::value_type, Val>);
+ static_assert(!HasIterCategory<Iter>);
+}
+
+void testAll() {
+ test<int>();
+ test<long>();
+ test<double>();
+ test<char>();
+}
diff --git a/libcxx/test/std/ranges/range.factories/range.istream.view/iterator/special_op.pass.cpp b/libcxx/test/std/ranges/range.factories/range.istream.view/iterator/special_op.pass.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/std/ranges/range.factories/range.istream.view/iterator/special_op.pass.cpp
@@ -0,0 +1,49 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+// iterator(const iterator&) = delete;
+// iterator(iterator&&) = default;
+// iterator& operator=(const iterator&) = delete;
+// iterator& operator=(iterator&&) = default;
+
+#include <ranges>
+
+#include <cassert>
+#include <sstream>
+
+using Iter = std::ranges::iterator_t<std::ranges::istream_view<int>>;
+static_assert(!std::copy_constructible<Iter>);
+static_assert(!std::is_copy_assignable_v<Iter>);
+static_assert(std::move_constructible<Iter>);
+static_assert(std::is_move_assignable_v<Iter>);
+
+int main(int, char**) {
+ // test move constructor
+ {
+ std::istringstream iss{"12 3"};
+ std::ranges::istream_view<int> isv{iss};
+ auto it = isv.begin();
+ auto it2 = std::move(it);
+ assert(*it2 == 12);
+ }
+
+ // test move assignment
+ {
+ std::istringstream iss1{"12 3"};
+ std::ranges::istream_view<int> isv1{iss1};
+ std::istringstream iss2{"45 6"};
+ std::ranges::istream_view<int> isv2{iss2};
+ auto it1 = isv1.begin();
+ assert(*it1 == 12);
+ it1 = isv2.begin();
+ assert(*it1 == 45);
+ }
+ return 0;
+}
diff --git a/libcxx/test/std/ranges/range.factories/range.istream.view/range.concept.compile.pass.cpp b/libcxx/test/std/ranges/range.factories/range.istream.view/range.concept.compile.pass.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/std/ranges/range.factories/range.istream.view/range.concept.compile.pass.cpp
@@ -0,0 +1,46 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+// concept checking istream_view
+
+#include <ranges>
+
+template <class Val, class CharT, class Traits = std::char_traits<CharT>>
+concept HasIstreamView = requires { typename std::ranges::basic_istream_view<Val, CharT, Traits>; };
+
+static_assert(HasIstreamView<int, char>);
+
+// movable Val
+struct UnMovable {
+ UnMovable() = default;
+ UnMovable(UnMovable&&) = delete;
+ friend std::istream& operator>>(std::istream& x, const UnMovable&) { return x; }
+};
+static_assert(!HasIstreamView<UnMovable, char>);
+
+// !default_Âinitializable<Val>
+struct NoDefaultCtor {
+ NoDefaultCtor(int) {}
+ friend std::istream& operator>>(std::istream& x, const NoDefaultCtor&) { return x; }
+};
+static_assert(!HasIstreamView<NoDefaultCtor, char>);
+
+// !stream-extractable<Val, CharT, Traits>
+struct Foo {};
+static_assert(!HasIstreamView<Foo, char>);
+
+template <class T>
+concept OnlyInputRange = std::ranges::input_range<T> && !
+std::ranges::forward_range<T>;
+
+static_assert(OnlyInputRange<std::ranges::istream_view<int>>);
+static_assert(OnlyInputRange<std::ranges::istream_view<long>>);
+static_assert(OnlyInputRange<std::ranges::istream_view<double>>);
+static_assert(OnlyInputRange<std::ranges::istream_view<char>>);