[libc++][ranges] Mark completed Ranges papers and issues as done, bump version macro

[var-const]

Summary

All C++20 Ranges papers and LWG issues are done, with the exception of
https://wg21.link/P2210R2 ("Superior String Splitting"), and marked as
such.

All of these were already implemented prior to this patch except bumping
the feature test macro __cpp_lib_ranges as required by
https://wg21.link/P2325R3 ("Views should not be required to be default
constructible"). Note that, even though P2325R3 was voted into C++23, it
was voted with a recommendation for vendors to retroactively apply the
change to C++20 (see https://github.com/cplusplus/papers/issues/1007).

[var-const]

libcxx/docs/ReleaseNotes.rst

57

This patch relies on https://reviews.llvm.org/D136268 being submitted.

65

Should we add any other papers that this patch marks as done (or that were marked as done recently) here? This one is probably worth calling out because it bumps the ranges version macro. I'm not sure if others are worth calling out since they focus on fixing defects rather than adding new features, what do you think?

libcxx/docs/Status/Cxx20Issues.csv

247

It looks like has-tuple-element's definition has been completely revamped in the Standard since that paper. I haven't done too much archeology on this, just verified that what we have is same as the current draft of the Standard.

libcxx/include/__ranges/join_view.h

231 ↗

(On Diff #482322)

This is the only thing I found that was missing.

libcxx/include/version

140

If we follow the suggestion from https://github.com/cplusplus/papers/issues/1007 to apply the change to C++20 retroactively, I presume it means we don't need different values of the macro for C++20 and C++23.

(Unfortunately, we missed the previous version bump of this macro to 201911L that should have happened when we marked P1716R3 as implemented)

[philnik]

libcxx/docs/ReleaseNotes.rst

65

I think it makes sense to list all papers. That allows people to quickly find out if a paper has been implemented that they are interested in, even if it's not a major change. I'm a lot more on the fence about LWG issues, since that would probably result in a lot of noise.

libcxx/include/version

140

Well, we'll need different values once we implement P2415R2 (which seems to be missing from the status page?), P2387R3 and P2494R2.

[var-const]

libcxx/include/version

140

Looking at https://github.com/cplusplus/papers/issues/1085, it appears that P2415R2 was also adopted as a DR against C++20. It is listed in docs/Status/Cxx20Papers.csv. But yeah, for the latter papers looks like we'll need different values.

[tcanens]

libcxx/include/__ranges/join_view.h

231 ↗

(On Diff #482322)

https://cplusplus.github.io/LWG/issue3569

[var-const]

Address feedback.

[var-const]

libcxx/include/__ranges/join_view.h

231 ↗

(On Diff #482322)

Thanks a lot! I missed that issue, reverted the constraint now.

[Mordante]

Thanks for working on this! In general LGTM, but I didn't verify all papers. I leave the final approval to @philnik.

libcxx/docs/Status/Cxx20Issues.csv

247

Should the then mark it as Complete instead. Nothing to do implies nothing was ever done.

libcxx/include/__ranges/join_view.h

231 ↗

(On Diff #482322)

FYI D140407 adds that LWG issue to the status table.

libcxx/include/version

140

I applied the same logic to the DR papers for format, so I agree that's what we should do.

[var-const]

libcxx/docs/ReleaseNotes.rst

65

Personally, I would prefer to only list major papers (I don't like having to sift through a bunch of minor papers that are sometimes just outgrowth of LWG issues to find significant new features, if any). I don't feel too strongly about it, though.

@ldionne Louis, do you think it makes more sense to list all implemented papers (even the ones with minor fixes) or only the major ones? I think I'll merge this patch as is but happy to follow up tomorrow with a fuller list if that's what we ultimately decide.

libcxx/include/version

140

Thanks for this context!

[var-const]

Address feedback

[Mordante]

libcxx/docs/ReleaseNotes.rst

65

IMO it depends a bit on how user visible the change is. A small paper that has a lot of user visible impact I would like to see. I think we can even omit large papers, when they have little impact. There are some papers changing mandates clauses in the library, probably not something users are interested in. This one for example https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2020/p2045r1.html, but there are larger papers.

[ldionne]

libcxx/docs/ReleaseNotes.rst

65

I agree with Mark. Release notes are for things that we want to call out, they are not a laundry list of everything we've done. People have the status pages for that.

libcxx/docs/FeatureTestMacroTable.rst

.. table:: Current Status
     ``__cpp_lib_latch``                               ``201907L``
     ------------------------------------------------- -----------------
     ``__cpp_lib_list_remove_return_type``             ``201806L``
     ------------------------------------------------- -----------------
     ``__cpp_lib_math_constants``                      ``201907L``
     ------------------------------------------------- -----------------
     ``__cpp_lib_polymorphic_allocator``               ``201902L``
     ------------------------------------------------- -----------------
-    ``__cpp_lib_ranges``                              ``201811L``
+    ``__cpp_lib_ranges``                              ``202106L``
     ------------------------------------------------- -----------------
     ``__cpp_lib_remove_cvref``                        ``201711L``
     ------------------------------------------------- -----------------
     ``__cpp_lib_semaphore``                           ``201907L``
     ------------------------------------------------- -----------------
     ``__cpp_lib_shared_ptr_arrays``                   ``201707L``
     ------------------------------------------------- -----------------
     ``__cpp_lib_shift``                               ``201806L``

libcxx/docs/ReleaseNotes.rst

 ongoing.
 
 Implemented Papers
 ------------------
 - P2499R0 - ``string_view`` range constructor should be ``explicit``
 - P2417R2 - A more constexpr bitset
 - P2445R1 - ``std::forward_like``
 - P2273R3 - Making ``std::unique_ptr`` constexpr
 - P0591R4 - Utility functions to implement uses-allocator construction
 - P2291R3 - Add Constexpr Modifiers to Functions ``to_chars`` and
   ``from_chars`` for Integral Types in ``<charconv>`` Header
 - P0220R1 - Adopt Library Fundamentals V1 TS Components for C++17
 - P0482R6 - char8_t: A type for UTF-8 characters and strings
 - P2438R2 - ``std::string::substr() &&``
 - P0600R1 - ``nodiscard`` in the library
 - P0339R6 - ``polymorphic_allocator<>`` as a vocabulary type
 - P1169R4 - ``static operator()``
 - P0415R1 - ``constexpr`` for ``std::complex``
 - P1208R6 - ``std::source_location``
 - P0323R12 - ``std::expected``
 - P1035R7 - Input Range Adaptors
+- P2325R3 - Views should not be required to be default constructible
 
 Improvements and New Features
 -----------------------------
 - Declarations of ``std::c8rtomb()`` and ``std::mbrtoc8()`` from P0482R6 are
   now provided when implementations in the global namespace are provided by
   the C library.
 - Implemented ``<memory_resource>`` header from C++17
 - `D122780 <https://reviews.llvm.org/D122780>`_ Improved the performance of std::sort

libcxx/docs/Status/Cxx20Issues.csv

 "`3286 <https://wg21.link/LWG3286>`__","``ranges::size``\  is not required to be valid after a call to ``ranges::begin``\  on an input range","Prague","|Complete|","15.0","|ranges|"
 "`3291 <https://wg21.link/LWG3291>`__","``iota_view::iterator``\  has the wrong ``iterator_category``\ ","Prague","|Complete|","15.0","|ranges|"
 "`3292 <https://wg21.link/LWG3292>`__","``iota_view``\  is under-constrained","Prague","|Complete|","15.0","|ranges|"
 "`3294 <https://wg21.link/LWG3294>`__","``zoned_time``\  deduction guides misinterprets ``string``\ /``char*``\ ","Prague","","","|chrono|"
 "`3296 <https://wg21.link/LWG3296>`__","Inconsistent default argument for ``basic_regex<>::assign``\ ","Prague","|Complete|",""
 "`3299 <https://wg21.link/LWG3299>`__","Pointers don't need customized iterator behavior","Prague","|Complete|","15.0","|ranges|"
 "`3300 <https://wg21.link/LWG3300>`__","Non-array ``ssize``\  overload is underconstrained","Prague","|Nothing To Do|",""
 "`3301 <https://wg21.link/LWG3301>`__","``transform_view::iterator``\  has incorrect ``iterator_category``\ ","Prague","|Complete|","15.0","|ranges|"
-"`3302 <https://wg21.link/LWG3302>`__","Range adaptor objects ``keys``\  and ``values``\  are unspecified","Prague","","","|ranges|"
+"`3302 <https://wg21.link/LWG3302>`__","Range adaptor objects ``keys``\  and ``values``\  are unspecified","Prague","|Complete|","16.0","|ranges|"
 "`3303 <https://wg21.link/LWG3303>`__","Bad ""``constexpr``\ "" marker for ``destroy/destroy_n``\ ","Prague","",""
 "`3304 <https://wg21.link/LWG3304>`__","Allocate functions of ``std::polymorphic_allocator``\  should require ``[[nodiscard]]``\ ","Prague","|Complete|","16.0"
 "`3307 <https://wg21.link/LWG3307>`__","``std::allocator<void>().allocate(n)``\ ","Prague","",""
 "`3310 <https://wg21.link/LWG3310>`__","Replace ``SIZE_MAX``\  with ``numeric_limits<size_t>::max()``\ ","Prague","|Complete|","16.0"
 "`3313 <https://wg21.link/LWG3313>`__","``join_view::iterator::operator--``\  is incorrectly constrained","Prague","|Complete|","14.0","|ranges|"
 "`3314 <https://wg21.link/LWG3314>`__","Is stream insertion behavior locale dependent when ``Period::type``\  is ``micro``\ ?","Prague","|Complete|","16.0","|chrono|"
 "`3315 <https://wg21.link/LWG3315>`__","Correct Allocator Default Behavior","Prague","",""
 "`3316 <https://wg21.link/LWG3316>`__","Correctly define epoch for ``utc_clock``\  / ``utc_timepoint``\ ","Prague","","","|chrono|"
 "`3317 <https://wg21.link/LWG3317>`__","Incorrect ``operator<<``\  for floating-point durations","Prague","","","|chrono|"
 "`3318 <https://wg21.link/LWG3318>`__","Clarify whether clocks can represent time before their epoch","Prague","","","|chrono|"
 "`3319 <https://wg21.link/LWG3319>`__","Properly reference specification of IANA time zone database","Prague","","","|chrono|"
 "`3320 <https://wg21.link/LWG3320>`__","``span::cbegin/cend``\  methods produce different results than ``std::[ranges::]cbegin/cend``\ ","Prague","|Complete|",""
 "`3321 <https://wg21.link/LWG3321>`__","``uninitialized_construct_using_allocator``\  should use ``construct_at``\ ","Prague","|Complete|","16.0"
-"`3323 <https://wg21.link/LWG3323>`__","``*has-tuple-element*``\  helper concept needs ``convertible_to``\ ","Prague","","","|ranges|"
+"`3323 <https://wg21.link/LWG3323>`__","``*has-tuple-element*``\  helper concept needs ``convertible_to``\ ","Prague","|Complete|","16.0","|ranges|"
 "`3324 <https://wg21.link/LWG3324>`__","Special-case ``std::strong/weak/partial_order``\  for pointers","Prague","|Complete|","14.0","|spaceship|"
 "`3325 <https://wg21.link/LWG3325>`__","Constrain return type of transformation function for ``transform_view``\ ","Prague","|Complete|","15.0","|ranges|"
 "`3326 <https://wg21.link/LWG3326>`__","``enable_view``\  has false positives","Prague","|Complete|","15.0","|ranges|"
 "`3327 <https://wg21.link/LWG3327>`__","Format alignment specifiers vs. text direction","Prague","|Nothing To Do|","","|format|"
 "`3328 <https://wg21.link/LWG3328>`__","Clarify that ``std::string``\  is not good for UTF-8","Prague","",""
 "`3329 <https://wg21.link/LWG3329>`__","``totally_ordered_with``\  both directly and indirectly requires ``common_reference_with``\ ","Prague","|Complete|","13.0"
 "`3330 <https://wg21.link/LWG3330>`__","Include ``<compare>``\  from most library headers","Prague","|Complete|","13.0","|spaceship|"
 "`3331 <https://wg21.link/LWG3331>`__","Define ``totally_ordered/_with``\  in terms of ``partially-ordered-with``\ ","Prague","|Complete|","13.0"

 "`3354 <https://wg21.link/LWG3354>`__","``has_strong_structural_equality``\  has a meaningless definition","Prague","|Nothing To Do|","","|spaceship|"
 "`3355 <https://wg21.link/LWG3355>`__","The memory algorithms should support move-only input iterators introduced by P1207","Prague","|Complete|","15.0","|ranges|"
 "`3356 <https://wg21.link/LWG3356>`__","``__cpp_lib_nothrow_convertible``\  should be ``__cpp_lib_is_nothrow_convertible``\ ","Prague","|Complete|","12.0"
 "`3358 <https://wg21.link/LWG3358>`__","|sect|\ [span.cons] is mistaken that ``to_address``\  can throw","Prague","",""
 "`3359 <https://wg21.link/LWG3359>`__","``<chrono>``\  leap second support should allow for negative leap seconds","Prague","","","|chrono|"
 "`3360 <https://wg21.link/LWG3360>`__","``three_way_comparable_with``\  is inconsistent with similar concepts","Prague","|Nothing To Do|","","|spaceship|"
 "`3362 <https://wg21.link/LWG3362>`__","Strike ``stop_source``\ 's ``operator!=``\ ","Prague","",""
 "`3363 <https://wg21.link/LWG3363>`__","``drop_while_view``\  should opt-out of ``sized_range``\ ","Prague","|Nothing To Do|","","|ranges|"
-"`3364 <https://wg21.link/LWG3364>`__","Initialize data members of ranges and their iterators","Prague","","","|ranges|"
+"`3364 <https://wg21.link/LWG3364>`__","Initialize data members of ranges and their iterators","Prague","|Complete|","16.0","|ranges|"
 "`3367 <https://wg21.link/LWG3367>`__","Integer-class conversions should not throw","Prague","|Nothing To Do|",""
 "`3369 <https://wg21.link/LWG3369>`__","``span``\ 's deduction-guide for built-in arrays doesn't work","Prague","|Complete|","14.0"
 "`3371 <https://wg21.link/LWG3371>`__","``visit_format_arg``\  and ``make_format_args``\  are not hidden friends","Prague","|Complete|","14.0","|format|"
 "`3372 <https://wg21.link/LWG3372>`__","``vformat_to``\  should not try to deduce ``Out``\  twice","Prague","|Complete|","14.0","|format|"
 "`3373 <https://wg21.link/LWG3373>`__","``{to,from}_chars_result``\  and ``format_to_n_result``\  need the  ""we really mean what we say"" wording","Prague","|Complete|","14.0","|format|"
 "`3374 <https://wg21.link/LWG3374>`__","P0653 + P1006 should have made the other ``std::to_address``\  overload ``constexpr``\ ","Prague","|Complete|","12.0"
 "`3375 <https://wg21.link/LWG3375>`__","``decay``\  in ``viewable_range``\  should be ``remove_cvref``\ ","Prague","|Complete|","15.0","|ranges|"
 "`3377 <https://wg21.link/LWG3377>`__","``elements_view::iterator``\  befriends a specialization of itself","Prague","|Nothing To Do|","","|ranges|"
 "`3379 <https://wg21.link/LWG3379>`__","""``safe``\ "" in several library names is misleading","Prague","|Complete|","15.0","|ranges|"
 "`3380 <https://wg21.link/LWG3380>`__","``common_type``\  and comparison categories","Prague","|Complete|","15.0","|spaceship|"
 "`3381 <https://wg21.link/LWG3381>`__","``begin``\  and ``data``\  must agree for ``contiguous_range``\ ","Prague","|Nothing To Do|","","|ranges|"
 "`3382 <https://wg21.link/LWG3382>`__","NTTP for ``pair``\  and ``array``\ ","Prague","",""
 "`3383 <https://wg21.link/LWG3383>`__","|sect|\ [time.zone.leap.nonmembers] ``sys_seconds``\  should be replaced with ``seconds``\ ","Prague","","","|chrono|"
 "`3384 <https://wg21.link/LWG3384>`__","``transform_view::*sentinel*``\  has an incorrect ``operator-``\ ","Prague","|Complete|","15.0","|ranges|"
 "`3385 <https://wg21.link/LWG3385>`__","``common_iterator``\  is not sufficiently constrained for non-copyable iterators","Prague","|Complete|","15.0","|ranges|"
 "`3387 <https://wg21.link/LWG3387>`__","|sect|\ [range.reverse.view] ``reverse_view<V>``\  unintentionally requires ``range<const V>``\ ","Prague","|Complete|","15.0","|ranges|"
-"`3388 <https://wg21.link/LWG3388>`__","``view``\  iterator types have ill-formed ``<=>``\  operators","Prague","","","|ranges|"
+"`3388 <https://wg21.link/LWG3388>`__","``view``\  iterator types have ill-formed ``<=>``\  operators","Prague","|Complete|","16.0","|ranges|"
 "`3389 <https://wg21.link/LWG3389>`__","A move-only iterator still does not have a ``counted_iterator``\ ","Prague","|Complete|","15.0","|ranges|"
 "`3390 <https://wg21.link/LWG3390>`__","``make_move_iterator()``\  cannot be used to construct a ``move_iterator``\  for a move-only iterator","Prague","|Complete|","14.0","|ranges|"
 "`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","|Nothing To Do|","16.0"
 "`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","|ranges|"

libcxx/docs/Status/Cxx20Papers.csv

 "`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","|Complete|","16.0","|ranges|"
 "`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","|Complete|","16.0"
 "`P1651R0 <https://wg21.link/P1651R0>`__","LWG","bind_front should not unwrap reference_wrapper","Cologne","|Complete|","13.0"
 "`P1652R1 <https://wg21.link/P1652R1>`__","LWG","Printf corner cases in std::format","Cologne","|Complete|","14.0"
 "`P1661R1 <https://wg21.link/P1661R1>`__","LWG","Remove dedicated precalculated hash lookup interface","Cologne","|Nothing To Do|",""
+<<<<<<< HEAD
 "`P1754R1 <https://wg21.link/P1754R1>`__","LWG","Rename concepts to standard_case for C++20, while we still can","Cologne","|In Progress|","","|ranges|"
 "","","","","","",""
+=======
+"`P1754R1 <https://wg21.link/P1754R1>`__","LWG","Rename concepts to standard_case for C++20, while we still can","Cologne","|Complete|","15.0","|ranges|"
+"","","","","",""
+>>>>>>> da0daa714aa9 ([libc++][ranges] Mark completed Ranges papers and issues as done, bump version macro)
 "`P0883R2 <https://wg21.link/P0883R2>`__","LWG","Fixing Atomic Initialization","Belfast","|Complete| [#note-P0883.1]_ [#note-P0883.2]_","14.0"
 "`P1391R4 <https://wg21.link/P1391R4>`__","LWG","Range constructor for std::string_view","Belfast","|Complete|","14.0","|ranges|"
 "`P1394R4 <https://wg21.link/P1394R4>`__","LWG","Range constructor for std::span","Belfast","|Complete|","14.0","|ranges|"
 "`P1456R1 <https://wg21.link/P1456R1>`__","LWG","Move-only views","Belfast","|Complete|","15.0","|ranges|"
 "`P1622R3 <https://wg21.link/P1622R3>`__","LWG","Mandating the Standard Library: Clause 32 - Thread support library","Belfast","* *",""
 "`P1645R1 <https://wg21.link/P1645R1>`__","LWG","constexpr for numeric algorithms","Belfast","|Complete|","12.0"
 "`P1686R2 <https://wg21.link/P1686R2>`__","LWG","Mandating the Standard Library: Clause 27 - Time library","Belfast","* *",""
 "`P1690R1 <https://wg21.link/P1690R1>`__","LWG","Refinement Proposal for P0919 Heterogeneous lookup for unordered containers","Belfast","|Complete|","12.0"
 "`P1716R3 <https://wg21.link/P1716R3>`__","LWG","ranges compare algorithm are over-constrained","Belfast","|Complete|","15.0","|ranges|"
 "`P1718R2 <https://wg21.link/P1718R2>`__","LWG","Mandating the Standard Library: Clause 25 - Algorithms library","Belfast","* *",""
 "`P1719R2 <https://wg21.link/P1719R2>`__","LWG","Mandating the Standard Library: Clause 26 - Numerics library","Belfast","* *",""
 "`P1720R2 <https://wg21.link/P1720R2>`__","LWG","Mandating the Standard Library: Clause 28 - Localization library","Belfast","* *",""
 "`P1721R2 <https://wg21.link/P1721R2>`__","LWG","Mandating the Standard Library: Clause 29 - Input/Output library","Belfast","* *",""
 "`P1722R2 <https://wg21.link/P1722R2>`__","LWG","Mandating the Standard Library: Clause 30 - Regular Expression library","Belfast","* *",""
 "`P1723R2 <https://wg21.link/P1723R2>`__","LWG","Mandating the Standard Library: Clause 31 - Atomics library","Belfast","* *",""
 "`P1855R0 <https://wg21.link/P1855R0>`__","LWG","Make ``<compare>``\  freestanding","Belfast","* *",""
-"`P1862R1 <https://wg21.link/P1862R1>`__","LWG","Ranges adaptors for non-copyable iterators","Belfast","* *","","|ranges|"
+"`P1862R1 <https://wg21.link/P1862R1>`__","LWG","Ranges adaptors for non-copyable iterators","Belfast","|Complete|","16.0","|ranges|"
 "`P1865R1 <https://wg21.link/P1865R1>`__","LWG","Add max() to latch and barrier","Belfast","|Complete|","11.0"
 "`P1869R1 <https://wg21.link/P1869R1>`__","LWG","Rename 'condition_variable_any' interruptible wait methods","Belfast","* *",""
 "`P1870R1 <https://wg21.link/P1870R1>`__","LWG","forwarding-range is too subtle","Belfast","|Complete|","15.0","|ranges|"
 "`P1871R1 <https://wg21.link/P1871R1>`__","LWG","Concept traits should be named after concepts","Belfast","|Complete|","14.0","|ranges|"
 "`P1872R0 <https://wg21.link/P1872R0>`__","LWG","span should have size_type, not index_type","Belfast","|Complete|","10.0"
 "`P1878R1 <https://wg21.link/P1878R1>`__","LWG","Constraining Readable Types","Belfast","|Complete|","15.0","|ranges|"
 "`P1892R1 <https://wg21.link/P1892R1>`__","LWG","Extended locale-specific presentation specifiers for std::format","Belfast","|Complete|","14.0"
 "`P1902R1 <https://wg21.link/P1902R1>`__","LWG","Missing feature-test macros 2018-2019","Belfast","* *",""
 "`P1959R0 <https://wg21.link/P1959R0>`__","LWG","Remove std::weak_equality and std::strong_equality","Belfast","|Nothing To Do|",""
 "`P1960R0 <https://wg21.link/P1960R0>`__","LWG","NB Comment Changes Reviewed by SG1","Belfast","* *",""
 "`P1961R0 <https://wg21.link/P1961R0>`__","LWG","Harmonizing the definitions of total order for pointers","Belfast","* *",""
 "`P1965R0 <https://wg21.link/P1965R0>`__","LWG","Blanket Wording for Specifying ""Hidden Friends""","Belfast","* *",""
 "","","","","","",""
 "`P0586R2 <https://wg21.link/P0586R2>`__","LWG","Safe integral comparisons","Prague","|Complete|","13.0"
 "`P0593R6 <https://wg21.link/P0593R6>`__","CWG","Implicit creation of objects for low-level object manipulation","Prague","* *",""
 "`P1115R3 <https://wg21.link/P1115R3>`__","LWG","Improving the Return Value of Erase-Like Algorithms II: Free erase/erase if","Prague","|Complete|","11.0"
 "`P1243R4 <https://wg21.link/P1243R4>`__","LWG","Rangify New Algorithms","Prague","|Complete|","15.0","|ranges|"
 "`P1460R1 <https://wg21.link/P1460R1>`__","LWG","Mandating the Standard Library: Clause 20 - Utilities library","Prague","* *",""
 "`P1739R4 <https://wg21.link/P1739R4>`__","LWG","Avoid template bloat for safe_ranges in combination with ""subrange-y"" view adaptors","Prague","|Complete|","15.0","|ranges|"
 "`P1831R1 <https://wg21.link/P1831R1>`__","LWG","Deprecating volatile: library","Prague","* *",""
 "`P1868R2 <https://wg21.link/P1868R2>`__","LWG","width: clarifying units of width and precision in std::format","Prague","|Complete|","14.0"
 "`P1937R2 <https://wg21.link/P1937R2>`__","CWG","Fixing inconsistencies between constexpr and consteval functions","Prague","* *",""
 "`P1956R1 <https://wg21.link/P1956R1>`__","LWG","On the names of low-level bit manipulation functions","Prague","|Complete|","12.0"
 "`P1957R2 <https://wg21.link/P1957R2>`__","CWG","Converting from ``T*``\  to bool should be considered narrowing (re: US 212)","Prague","* *",""
-"`P1963R0 <https://wg21.link/P1963R0>`__","LWG","Fixing US 313","Prague","* *","","|ranges|"
+"`P1963R0 <https://wg21.link/P1963R0>`__","LWG","Fixing US 313","Prague","* *","",""
 "`P1964R2 <https://wg21.link/P1964R2>`__","LWG","Wording for boolean-testable","Prague","|Complete|","13.0"
 "`P1970R2 <https://wg21.link/P1970R2>`__","LWG","Consistency for size() functions: Add ranges::ssize","Prague","|Complete|","15.0","|ranges|"
 "`P1973R1 <https://wg21.link/P1973R1>`__","LWG","Rename ""_default_init"" Functions, Rev1","Prague","* *",""
 "`P1976R2 <https://wg21.link/P1976R2>`__","LWG","Fixed-size span construction from dynamic range","Prague","|Complete|","11.0","|ranges|"
 "`P1981R0 <https://wg21.link/P1981R0>`__","LWG","Rename leap to leap_second","Prague","* *",""
 "`P1982R0 <https://wg21.link/P1982R0>`__","LWG","Rename link to time_zone_link","Prague","* *",""
 "`P1983R0 <https://wg21.link/P1983R0>`__","LWG","Wording for GB301, US296, US292, US291, and US283","Prague","|Complete|","15.0","|ranges|"
 "`P1994R1 <https://wg21.link/P1994R1>`__","LWG","elements_view needs its own sentinel","Prague","Complete","16.0","|ranges|"
 "`P2002R1 <https://wg21.link/P2002R1>`__","CWG","Defaulted comparison specification cleanups","Prague","* *",""
 "`P2045R1 <https://wg21.link/P2045R1>`__","LWG","Missing Mandates for the standard library","Prague","* *",""
 "`P2085R0 <https://wg21.link/P2085R0>`__","CWG","Consistent defaulted comparisons","Prague","* *",""
 "`P2091R0 <https://wg21.link/P2091R0>`__","LWG","Issues with range access CPOs","Prague","|Complete|","15.0","|ranges|"
 "`P2101R0 <https://wg21.link/P2101R0>`__","LWG","'Models' subsumes 'satisfies' (Wording for US298 and US300)","Prague","* *",""
 "`P2102R0 <https://wg21.link/P2102R0>`__","LWG","Make 'implicit expression variations' more explicit (Wording for US185)","Prague","* *",""
 "`P2106R0 <https://wg21.link/P2106R0>`__","LWG","Alternative wording for GB315 and GB316","Prague","|Complete|","15.0","|ranges|"
 "`P2116R0 <https://wg21.link/P2116R0>`__","LWG","Remove tuple-like protocol support from fixed-extent span","Prague","|Complete|","11.0"
 "","","","","","",""
 "`P2231R1 <https://wg21.link/P2231R1>`__","LWG","Missing constexpr in std::optional and std::variant","June 2021","|Partial| [#note-P2231]_","13.0"
-"`P2325R3 <https://wg21.link/P2325R3>`__","LWG","Views should not be required to be default constructible","June 2021","|In progress|","","|ranges|"
-"`P2210R2 <https://wg21.link/P2210R2>`__","LWG",Superior String Splitting,"June 2021","|In progress|","","|ranges|"
-"`P2216R3 <https://wg21.link/P2216R3>`__","LWG",std::format improvements,"June 2021","|Complete|","15.0"
-"`P2281R1 <https://wg21.link/P2281R1>`__","LWG",Clarifying range adaptor objects,"June 2021","|Complete|","14.0","|ranges|"
-"`P2328R1 <https://wg21.link/P2328R1>`__","LWG",join_view should join all views of ranges,"June 2021","","","|ranges|"
-"`P2367R0 <https://wg21.link/P2367R0>`__","LWG",Remove misuses of list-initialization from Clause 24,"June 2021","","","|ranges|"
+"`P2325R3 <https://wg21.link/P2325R3>`__","LWG","Views should not be required to be default constructible","June 2021","|Complete|","16.0","|ranges|"
+"`P2210R2 <https://wg21.link/P2210R2>`__","LWG","Superior String Splitting","June 2021","|In progress|","","|ranges|"
+"`P2216R3 <https://wg21.link/P2216R3>`__","LWG","std::format improvements","June 2021","|Complete|","15.0"
+"`P2281R1 <https://wg21.link/P2281R1>`__","LWG","Clarifying range adaptor objects","June 2021","|Complete|","14.0","|ranges|"
+"`P2328R1 <https://wg21.link/P2328R1>`__","LWG","join_view should join all views of ranges","June 2021","|Complete|","15.0","|ranges|"
+"`P2367R0 <https://wg21.link/P2367R0>`__","LWG","Remove misuses of list-initialization from Clause 24","June 2021","|Complete|","15.0","|ranges|"
 "","","","","","",""
 "`P2372R3 <https://wg21.link/P2372R3>`__","LWG","Fixing locale handling in chrono formatters","October 2021","|In Progress|",""
 "`P2415R2 <https://wg21.link/P2415R2>`__","LWG","What is a ``view``","October 2021","|Complete|","14.0","|ranges|"
 "`P2418R2 <https://wg21.link/P2418R2>`__","LWG","Add support for ``std::generator``-like types to ``std::format``","October 2021","|Complete|","15.0"
 "`P2432R1 <https://wg21.link/P2432R1>`__","LWG","Fix ``istream_view``","October 2021","|Complete|","16.0","|ranges|"

libcxx/docs/Status/RangesViews.csv

 C++20,`drop <https://wg21.link/P1035R7>`_,Zoe Carver,`D102037 <https://llvm.org/D102037>`_,✅
 C++20,`drop_while <https://wg21.link/P1035R7>`_,Hui Xie,`D135460 <https://llvm.org/D135460>`_,✅
 C++20,`join <https://wg21.link/P0896R4>`_,Zoe Carver,`D107671 <https://llvm.org/D107671>`_,✅
 C++20,`split <https://wg21.link/P2210R2>`_,Unassigned,No patch yet,Not started
 C++20,`lazy_split <https://wg21.link/P0896R4>`_,Zoe Carver and Konstantin Varlamov,`D107500 <https://llvm.org/D107500>`_,✅
 C++20,`counted <https://wg21.link/P0896R4>`_,Zoe Carver,`D106923 <https://llvm.org/D106923>`_,✅
 C++20,`common <https://wg21.link/P0896R4>`_,Zoe Carver,`D105753 <https://llvm.org/D105753>`_,✅
 C++20,`reverse <https://wg21.link/P0896R4>`_,Zoe Carver,`D107096 <https://llvm.org/D107096>`_,✅
-C++20,`elements / keys / values <https://wg21.link/P1035R7>`_,Hui Xie,`D136268 <https://llvm.org/D136268>`_,Under review
+C++20,`elements / keys / values <https://wg21.link/P1035R7>`_,Hui Xie,`D136268 <https://llvm.org/D136268>`_,✅
 C++20,`istream <https://wg21.link/P1035R7>`_,Hui Xie,`D133317 <https://llvm.org/D133317>`_,✅
 ,,,,
 ,,,,
 ,,,,
 C++23,`repeat <https://wg21.link/P2474R2>`_,Unassigned,No patch yet,Not started
 C++23,`cartesian_product <https://wg21.link/P2374R4>`_,Unassigned,No patch yet,Not started
 C++23,`zip <https://wg21.link/P2321R2>`_,Hui Xie,`D122806 <https://llvm.org/D122806>`_,✅
 C++23,`zip_transform <https://wg21.link/P2321R2>`_,Hui Xie,No patch yet,Not started

libcxx/include/version

 __cpp_lib_not_fn                                        201603L <functional>
 __cpp_lib_null_iterators                                201304L <iterator>
 __cpp_lib_optional                                      202110L <optional>
                                                         201606L // C++17
 __cpp_lib_out_ptr                                       202106L <memory>
 __cpp_lib_parallel_algorithm                            201603L <algorithm> <numeric>
 __cpp_lib_polymorphic_allocator                         201902L <memory_resource>
 __cpp_lib_quoted_string_io                              201304L <iomanip>
-__cpp_lib_ranges                                        201811L <algorithm> <functional> <iterator>
+__cpp_lib_ranges                                        202106L <algorithm> <functional> <iterator>
                                                                 <memory> <ranges>
 __cpp_lib_ranges_chunk                                  202202L <ranges>
 __cpp_lib_ranges_chunk_by                               202202L <ranges>
 __cpp_lib_ranges_iota                                   202202L <numeric>
 __cpp_lib_ranges_join_with                              202202L <ranges>
 __cpp_lib_ranges_slide                                  202202L <ranges>
 __cpp_lib_ranges_starts_ends_with                       202106L <algorithm>
 __cpp_lib_ranges_to_container                           202202L <deque> <forward_list> <list>

 // #   define __cpp_lib_jthread                            201911L
 # endif
 # if !defined(_LIBCPP_HAS_NO_THREADS) && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_latch)
 #   define __cpp_lib_latch                              201907L
 # endif
 # define __cpp_lib_list_remove_return_type              201806L
 # define __cpp_lib_math_constants                       201907L
 # define __cpp_lib_polymorphic_allocator                201902L
-# define __cpp_lib_ranges                               201811L
+# define __cpp_lib_ranges                               202106L
 # define __cpp_lib_remove_cvref                         201711L
 # if !defined(_LIBCPP_HAS_NO_THREADS) && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_semaphore)
 #   define __cpp_lib_semaphore                          201907L
 # endif
 # undef  __cpp_lib_shared_ptr_arrays
 # define __cpp_lib_shared_ptr_arrays                    201707L
 # define __cpp_lib_shift                                201806L
 // # define __cpp_lib_smart_ptr_for_overwrite              202002L

libcxx/test/std/language.support/support.limits/support.limits.general/algorithm.version.compile.pass.cpp

 // <algorithm>
 
 // Test the feature test macros defined by <algorithm>
 
 /*  Constant                                 Value
     __cpp_lib_clamp                          201603L [C++17]
     __cpp_lib_constexpr_algorithms           201806L [C++20]
     __cpp_lib_parallel_algorithm             201603L [C++17]
-    __cpp_lib_ranges                         201811L [C++20]
+    __cpp_lib_ranges                         202106L [C++20]
     __cpp_lib_ranges_starts_ends_with        202106L [C++2b]
     __cpp_lib_robust_nonmodifying_seq_ops    201304L [C++14]
     __cpp_lib_sample                         201603L [C++17]
     __cpp_lib_shift                          201806L [C++20]
 */
 
 #include <algorithm>
 #include "test_macros.h"

 #   ifdef __cpp_lib_parallel_algorithm
 #     error "__cpp_lib_parallel_algorithm should not be defined because it is unimplemented in libc++!"
 #   endif
 # endif
 
 # ifndef __cpp_lib_ranges
 #   error "__cpp_lib_ranges should be defined in c++20"
 # endif
-# if __cpp_lib_ranges != 201811L
-#   error "__cpp_lib_ranges should have the value 201811L in c++20"
+# if __cpp_lib_ranges != 202106L
+#   error "__cpp_lib_ranges should have the value 202106L in c++20"
 # endif
 
 # ifdef __cpp_lib_ranges_starts_ends_with
 #   error "__cpp_lib_ranges_starts_ends_with should not be defined before c++2b"
 # endif
 
 # ifndef __cpp_lib_robust_nonmodifying_seq_ops
 #   error "__cpp_lib_robust_nonmodifying_seq_ops should be defined in c++20"

 #   ifdef __cpp_lib_parallel_algorithm
 #     error "__cpp_lib_parallel_algorithm should not be defined because it is unimplemented in libc++!"
 #   endif
 # endif
 
 # ifndef __cpp_lib_ranges
 #   error "__cpp_lib_ranges should be defined in c++2b"
 # endif
-# if __cpp_lib_ranges != 201811L
-#   error "__cpp_lib_ranges should have the value 201811L in c++2b"
+# if __cpp_lib_ranges != 202106L
+#   error "__cpp_lib_ranges should have the value 202106L in c++2b"
 # endif
 
 # if !defined(_LIBCPP_VERSION)
 #   ifndef __cpp_lib_ranges_starts_ends_with
 #     error "__cpp_lib_ranges_starts_ends_with should be defined in c++2b"
 #   endif
 #   if __cpp_lib_ranges_starts_ends_with != 202106L
 #     error "__cpp_lib_ranges_starts_ends_with should have the value 202106L in c++2b"

libcxx/test/std/language.support/support.limits/support.limits.general/functional.version.compile.pass.cpp

/*  Constant                           Value
     __cpp_lib_bind_back                202202L [C++2b]
     __cpp_lib_bind_front               201907L [C++20]
     __cpp_lib_boyer_moore_searcher     201603L [C++17]
     __cpp_lib_constexpr_functional     201907L [C++20]
     __cpp_lib_invoke                   201411L [C++17]
     __cpp_lib_invoke_r                 202106L [C++2b]
     __cpp_lib_move_only_function       202110L [C++2b]
     __cpp_lib_not_fn                   201603L [C++17]
-    __cpp_lib_ranges                   201811L [C++20]
+    __cpp_lib_ranges                   202106L [C++20]
     __cpp_lib_result_of_sfinae         201210L [C++14]
     __cpp_lib_transparent_operators    201210L [C++14]
                                        201510L [C++17]
     __cpp_lib_unwrap_ref               201811L [C++20]
 */
 
 #include <functional>
 #include "test_macros.h"

 # endif
 # if __cpp_lib_not_fn != 201603L
 #   error "__cpp_lib_not_fn should have the value 201603L in c++20"
 # endif
 
 # ifndef __cpp_lib_ranges
 #   error "__cpp_lib_ranges should be defined in c++20"
 # endif
-# if __cpp_lib_ranges != 201811L
-#   error "__cpp_lib_ranges should have the value 201811L in c++20"
+# if __cpp_lib_ranges != 202106L
+#   error "__cpp_lib_ranges should have the value 202106L in c++20"
 # endif
 
 # ifndef __cpp_lib_result_of_sfinae
 #   error "__cpp_lib_result_of_sfinae should be defined in c++20"
 # endif
 # if __cpp_lib_result_of_sfinae != 201210L
 #   error "__cpp_lib_result_of_sfinae should have the value 201210L in c++20"
 # endif

 # endif
 # if __cpp_lib_not_fn != 201603L
 #   error "__cpp_lib_not_fn should have the value 201603L in c++2b"
 # endif
 
 # ifndef __cpp_lib_ranges
 #   error "__cpp_lib_ranges should be defined in c++2b"
 # endif
-# if __cpp_lib_ranges != 201811L
-#   error "__cpp_lib_ranges should have the value 201811L in c++2b"
+# if __cpp_lib_ranges != 202106L
+#   error "__cpp_lib_ranges should have the value 202106L in c++2b"
 # endif
 
 # ifndef __cpp_lib_result_of_sfinae
 #   error "__cpp_lib_result_of_sfinae should be defined in c++2b"
 # endif
 # if __cpp_lib_result_of_sfinae != 201210L
 #   error "__cpp_lib_result_of_sfinae should have the value 201210L in c++2b"
 # endif

libcxx/test/std/language.support/support.limits/support.limits.general/iterator.version.compile.pass.cpp

 
 /*  Constant                                Value
     __cpp_lib_array_constexpr               201603L [C++17]
                                             201811L [C++20]
     __cpp_lib_constexpr_iterator            201811L [C++20]
     __cpp_lib_make_reverse_iterator         201402L [C++14]
     __cpp_lib_nonmember_container_access    201411L [C++17]
     __cpp_lib_null_iterators                201304L [C++14]
-    __cpp_lib_ranges                        201811L [C++20]
+    __cpp_lib_ranges                        202106L [C++20]
     __cpp_lib_ssize                         201902L [C++20]
 */
 
 #include <iterator>
 #include "test_macros.h"
 
 #if TEST_STD_VER < 14
 

 # endif
 # if __cpp_lib_null_iterators != 201304L
 #   error "__cpp_lib_null_iterators should have the value 201304L in c++20"
 # endif
 
 # ifndef __cpp_lib_ranges
 #   error "__cpp_lib_ranges should be defined in c++20"
 # endif
-# if __cpp_lib_ranges != 201811L
-#   error "__cpp_lib_ranges should have the value 201811L in c++20"
+# if __cpp_lib_ranges != 202106L
+#   error "__cpp_lib_ranges should have the value 202106L in c++20"
 # endif
 
 # ifndef __cpp_lib_ssize
 #   error "__cpp_lib_ssize should be defined in c++20"
 # endif
 # if __cpp_lib_ssize != 201902L
 #   error "__cpp_lib_ssize should have the value 201902L in c++20"
 # endif

 # endif
 # if __cpp_lib_null_iterators != 201304L
 #   error "__cpp_lib_null_iterators should have the value 201304L in c++2b"
 # endif
 
 # ifndef __cpp_lib_ranges
 #   error "__cpp_lib_ranges should be defined in c++2b"
 # endif
-# if __cpp_lib_ranges != 201811L
-#   error "__cpp_lib_ranges should have the value 201811L in c++2b"
+# if __cpp_lib_ranges != 202106L
+#   error "__cpp_lib_ranges should have the value 202106L in c++2b"
 # endif
 
 # ifndef __cpp_lib_ssize
 #   error "__cpp_lib_ssize should be defined in c++2b"
 # endif
 # if __cpp_lib_ssize != 201902L
 #   error "__cpp_lib_ssize should have the value 201902L in c++2b"
 # endif
 
 #endif // TEST_STD_VER > 20
 

libcxx/test/std/language.support/support.limits/support.limits.general/memory.version.compile.pass.cpp

/*  Constant                                      Value
     __cpp_lib_assume_aligned                      201811L [C++20]
     __cpp_lib_atomic_value_initialization         201911L [C++20]
     __cpp_lib_constexpr_dynamic_alloc             201907L [C++20]
     __cpp_lib_constexpr_memory                    201811L [C++20]
                                                   202202L [C++2b]
     __cpp_lib_enable_shared_from_this             201603L [C++17]
     __cpp_lib_make_unique                         201304L [C++14]
     __cpp_lib_out_ptr                             202106L [C++2b]
-    __cpp_lib_ranges                              201811L [C++20]
+    __cpp_lib_ranges                              202106L [C++20]
     __cpp_lib_raw_memory_algorithms               201606L [C++17]
     __cpp_lib_shared_ptr_arrays                   201611L [C++17]
                                                   201707L [C++20]
     __cpp_lib_shared_ptr_weak_type                201606L [C++17]
     __cpp_lib_smart_ptr_for_overwrite             202002L [C++20]
     __cpp_lib_to_address                          201711L [C++20]
     __cpp_lib_transparent_operators               201210L [C++14]
                                                   201510L [C++17]

 
 # ifdef __cpp_lib_out_ptr
 #   error "__cpp_lib_out_ptr should not be defined before c++2b"
 # endif
 
 # ifndef __cpp_lib_ranges
 #   error "__cpp_lib_ranges should be defined in c++20"
 # endif
-# if __cpp_lib_ranges != 201811L
-#   error "__cpp_lib_ranges should have the value 201811L in c++20"
+# if __cpp_lib_ranges != 202106L
+#   error "__cpp_lib_ranges should have the value 202106L in c++20"
 # endif
 
 # ifndef __cpp_lib_raw_memory_algorithms
 #   error "__cpp_lib_raw_memory_algorithms should be defined in c++20"
 # endif
 # if __cpp_lib_raw_memory_algorithms != 201606L
 #   error "__cpp_lib_raw_memory_algorithms should have the value 201606L in c++20"
 # endif

 #   ifdef __cpp_lib_out_ptr
 #     error "__cpp_lib_out_ptr should not be defined because it is unimplemented in libc++!"
 #   endif
 # endif
 
 # ifndef __cpp_lib_ranges
 #   error "__cpp_lib_ranges should be defined in c++2b"
 # endif
-# if __cpp_lib_ranges != 201811L
-#   error "__cpp_lib_ranges should have the value 201811L in c++2b"
+# if __cpp_lib_ranges != 202106L
+#   error "__cpp_lib_ranges should have the value 202106L in c++2b"
 # endif
 
 # ifndef __cpp_lib_raw_memory_algorithms
 #   error "__cpp_lib_raw_memory_algorithms should be defined in c++2b"
 # endif
 # if __cpp_lib_raw_memory_algorithms != 201606L
 #   error "__cpp_lib_raw_memory_algorithms should have the value 201606L in c++2b"
 # endif

libcxx/test/std/language.support/support.limits/support.limits.general/ranges.version.compile.pass.cpp

 //
 // clang-format off
 
 // <ranges>
 
 // Test the feature test macros defined by <ranges>
 
 /*  Constant                      Value
-    __cpp_lib_ranges              201811L [C++20]
+    __cpp_lib_ranges              202106L [C++20]
     __cpp_lib_ranges_chunk        202202L [C++2b]
     __cpp_lib_ranges_chunk_by     202202L [C++2b]
     __cpp_lib_ranges_join_with    202202L [C++2b]
     __cpp_lib_ranges_slide        202202L [C++2b]
     __cpp_lib_ranges_zip          202110L [C++2b]
 */
 
 #include <ranges>

 #   error "__cpp_lib_ranges_zip should not be defined before c++2b"
 # endif
 
 #elif TEST_STD_VER == 20
 
 # ifndef __cpp_lib_ranges
 #   error "__cpp_lib_ranges should be defined in c++20"
 # endif
-# if __cpp_lib_ranges != 201811L
-#   error "__cpp_lib_ranges should have the value 201811L in c++20"
+# if __cpp_lib_ranges != 202106L
+#   error "__cpp_lib_ranges should have the value 202106L in c++20"
 # endif
 
 # ifdef __cpp_lib_ranges_chunk
 #   error "__cpp_lib_ranges_chunk should not be defined before c++2b"
 # endif
 
 # ifdef __cpp_lib_ranges_chunk_by
 #   error "__cpp_lib_ranges_chunk_by should not be defined before c++2b"

 #   error "__cpp_lib_ranges_zip should not be defined before c++2b"
 # endif
 
 #elif TEST_STD_VER > 20
 
 # ifndef __cpp_lib_ranges
 #   error "__cpp_lib_ranges should be defined in c++2b"
 # endif
-# if __cpp_lib_ranges != 201811L
-#   error "__cpp_lib_ranges should have the value 201811L in c++2b"
+# if __cpp_lib_ranges != 202106L
+#   error "__cpp_lib_ranges should have the value 202106L in c++2b"
 # endif
 
 # if !defined(_LIBCPP_VERSION)
 #   ifndef __cpp_lib_ranges_chunk
 #     error "__cpp_lib_ranges_chunk should be defined in c++2b"
 #   endif
 #   if __cpp_lib_ranges_chunk != 202202L
 #     error "__cpp_lib_ranges_chunk should have the value 202202L in c++2b"

libcxx/test/std/language.support/support.limits/support.limits.general/version.version.compile.pass.cpp

/*  Constant                                       Value
     __cpp_lib_not_fn                               201603L [C++17]
     __cpp_lib_null_iterators                       201304L [C++14]
     __cpp_lib_optional                             201606L [C++17]
                                                    202110L [C++2b]
     __cpp_lib_out_ptr                              202106L [C++2b]
     __cpp_lib_parallel_algorithm                   201603L [C++17]
     __cpp_lib_polymorphic_allocator                201902L [C++20]
     __cpp_lib_quoted_string_io                     201304L [C++14]
-    __cpp_lib_ranges                               201811L [C++20]
+    __cpp_lib_ranges                               202106L [C++20]
     __cpp_lib_ranges_chunk                         202202L [C++2b]
     __cpp_lib_ranges_chunk_by                      202202L [C++2b]
     __cpp_lib_ranges_iota                          202202L [C++2b]
     __cpp_lib_ranges_join_with                     202202L [C++2b]
     __cpp_lib_ranges_slide                         202202L [C++2b]
     __cpp_lib_ranges_starts_ends_with              202106L [C++2b]
     __cpp_lib_ranges_to_container                  202202L [C++2b]
     __cpp_lib_ranges_zip                           202110L [C++2b]

 # endif
 # if __cpp_lib_quoted_string_io != 201304L
 #   error "__cpp_lib_quoted_string_io should have the value 201304L in c++20"
 # endif
 
 # ifndef __cpp_lib_ranges
 #   error "__cpp_lib_ranges should be defined in c++20"
 # endif
-# if __cpp_lib_ranges != 201811L
-#   error "__cpp_lib_ranges should have the value 201811L in c++20"
+# if __cpp_lib_ranges != 202106L
+#   error "__cpp_lib_ranges should have the value 202106L in c++20"
 # endif
 
 # ifdef __cpp_lib_ranges_chunk
 #   error "__cpp_lib_ranges_chunk should not be defined before c++2b"
 # endif
 
 # ifdef __cpp_lib_ranges_chunk_by
 #   error "__cpp_lib_ranges_chunk_by should not be defined before c++2b"

 # endif
 # if __cpp_lib_quoted_string_io != 201304L
 #   error "__cpp_lib_quoted_string_io should have the value 201304L in c++2b"
 # endif
 
 # ifndef __cpp_lib_ranges
 #   error "__cpp_lib_ranges should be defined in c++2b"
 # endif
-# if __cpp_lib_ranges != 201811L
-#   error "__cpp_lib_ranges should have the value 201811L in c++2b"
+# if __cpp_lib_ranges != 202106L
+#   error "__cpp_lib_ranges should have the value 202106L in c++2b"
 # endif
 
 # if !defined(_LIBCPP_VERSION)
 #   ifndef __cpp_lib_ranges_chunk
 #     error "__cpp_lib_ranges_chunk should be defined in c++2b"
 #   endif
 #   if __cpp_lib_ranges_chunk != 202202L
 #     error "__cpp_lib_ranges_chunk should have the value 202202L in c++2b"

libcxx/test/std/ranges/range.adaptors/range.join.view/types.h

 
 inline int globalBuffer[4][4] = {
     {1111, 2222, 3333, 4444},
     {555, 666, 777, 888},
     {99, 1010, 1111, 1212},
     {13, 14, 15, 16},
 };
 
-struct ChildView : std::ranges::view_base {
+template <template<class...> class Iter>
+struct ChildViewBase : std::ranges::view_base {
   int* ptr_;
 
-  using iterator = cpp20_input_iterator<int*>;
-  using const_iterator = cpp20_input_iterator<const int*>;
+  using iterator = Iter<int*>;
+  using const_iterator = Iter<const int*>;
   using sentinel = sentinel_wrapper<iterator>;
   using const_sentinel = sentinel_wrapper<const_iterator>;
 
-  constexpr ChildView(int* ptr = globalBuffer[0]) : ptr_(ptr) {}
-  ChildView(const ChildView&) = delete;
-  ChildView(ChildView&&) = default;
-  ChildView& operator=(const ChildView&) = delete;
-  ChildView& operator=(ChildView&&) = default;
+  constexpr ChildViewBase(int* ptr = globalBuffer[0]) : ptr_(ptr) {}
+  ChildViewBase(const ChildViewBase&) = delete;
+  ChildViewBase(ChildViewBase&&) = default;
+  ChildViewBase& operator=(const ChildViewBase&) = delete;
+  ChildViewBase& operator=(ChildViewBase&&) = default;
 
   constexpr iterator begin() { return iterator(ptr_); }
   constexpr const_iterator begin() const { return const_iterator(ptr_); }
   constexpr sentinel end() { return sentinel(iterator(ptr_ + 4)); }
   constexpr const_sentinel end() const { return const_sentinel(const_iterator(ptr_ + 4)); }
 };
+using ChildView = ChildViewBase<cpp20_input_iterator>;
 
 inline ChildView globalChildren[4] = {
     ChildView(globalBuffer[0]),
     ChildView(globalBuffer[1]),
     ChildView(globalBuffer[2]),
     ChildView(globalBuffer[3]),
 };
 

libcxx/utils/generate_feature_test_macro_components.py

feature_test_macros = [ add_version_header(x) for x in [
     "values": { "c++20": 201902 },
     "headers": ["memory_resource"],
   }, {
     "name": "__cpp_lib_quoted_string_io",
     "values": { "c++14": 201304 },
     "headers": ["iomanip"],
   }, {
     "name": "__cpp_lib_ranges",
-    "values": { "c++20": 201811 },
+    "values": { "c++20": 202106 },
     "headers": ["algorithm", "functional", "iterator", "memory", "ranges"],
   }, {
     "name": "__cpp_lib_ranges_chunk",
     "values": { "c++2b": 202202 },
     "headers": ["ranges"],
     "unimplemented": True,
   }, {
     "name": "__cpp_lib_ranges_chunk_by",