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: Remove std::allocator full specialization - #2726

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Stephan T. Lavavej (StephanTLavavej) merged 27 commits into
microsoft:mainfrom
frederick-vs-ja:remove-allocator-void
May 24, 2022
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: Remove std::allocator full specialization#2726
Stephan T. Lavavej (StephanTLavavej) merged 27 commits into
microsoft:mainfrom
frederick-vs-ja:remove-allocator-void

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@frederick-vs-ja A. Jiang (frederick-vs-ja) commented May 17, 2022

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The removal of std::allocator full specialization is observable via SFINAE techniques. As of C++20, using std::allocator::allocate is no longer a substitution failure, but a hard error. This PR tests such changes.

This PR also removes propagate_on_container_move_assignment and is_always_equal from std::allocator full specialization according to N4659. It seems that MSVC STL applied LWG-2103 and LWG-2108 (WG21-N4258) to std::allocator full specialization, but these member types haven't gone into std::allocator in C++17, see N4659 [depr.default.allocator].

Works towards WG21-P0619.

Fixes #527.

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A. Jiang (frederick-vs-ja) requested a review from a team as a code owner May 17, 2022 06:46
@StephanTLavavej Stephan T. Lavavej (StephanTLavavej) added the bug Something isn't working label May 18, 2022
CaseyCarter
Casey Carter (CaseyCarter) suggested changes May 18, 2022
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Comment thread tests/std/tests/GH_000527_remove_allocator_void/test.compile.pass.cpp Outdated
Comment thread stl/inc/xmemory Outdated
Comment thread stl/inc/xmemory Outdated
Comment thread stl/inc/xmemory
Comment thread stl/inc/yvals_core.h Outdated
CaseyCarter
Casey Carter (CaseyCarter) approved these changes May 18, 2022
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Comment thread tests/std/tests/GH_000527_remove_allocator_void/test.compile.pass.cpp
Comment thread tests/std/tests/GH_000527_remove_allocator_void/test.compile.pass.cpp
StephanTLavavej
Stephan T. Lavavej (StephanTLavavej) reviewed May 20, 2022
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Comment thread tests/std/tests/GH_000527_remove_allocator_void/test.compile.pass.cpp
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@StephanTLavavej

Stephan T. Lavavej (StephanTLavavej) commented May 20, 2022

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Thanks! I pushed a couple of style changes.

CaseyCarter
Casey Carter (CaseyCarter) approved these changes May 20, 2022
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Comment thread tests/std/tests/GH_000527_remove_allocator_void/test.compile.pass.cpp
constexpr bool has_cxx20 = false;
#endif

STATIC_ASSERT(has_cxx20 == has_member_size_type>);

@CaseyCarter Casey Carter (CaseyCarter) May 20, 2022 •
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Pure style, and totally not worth resetting testing if we change nothing else: I would have written these as [Actual value] == [Expected value], which I think is more consistent with our test conventions.

@StephanTLavavej Stephan T. Lavavej (StephanTLavavej) May 22, 2022

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That's my preferred style too - but I did it this way so that they would line up, and make the pattern obvious.

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Stephan T. Lavavej (StephanTLavavej) commented May 21, 2022

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I'm mirroring this to the MSVC-internal repo - please notify me if any further changes are pushed.

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Stephan T. Lavavej (StephanTLavavej) merged commit 4761b6d into microsoft:main May 24, 2022
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Stephan T. Lavavej (StephanTLavavej) commented May 24, 2022

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Thanks for fixing this C++20 conformance issue! ✅ 😸 🚀

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A. Jiang (frederick-vs-ja) deleted the remove-allocator-void branch May 24, 2022 01:22
Igor Zhukov (fsb4000) pushed a commit to fsb4000/STL that referenced this pull request Aug 13, 2022
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: Remove std::allocator full specialization (micro…
08705f3 
…soft#2726)

Co-authored-by: Casey Carter 
Co-authored-by: Stephan T. Lavavej
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@StephanTLavavej Stephan T. Lavavej (StephanTLavavej) StephanTLavavej approved these changes
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@CaseyCarter Casey Carter (CaseyCarter) CaseyCarter approved these changes
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: We should implement C++20's removal of allocator

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