[libcxx-commits] [PATCH] D111197: [libc++] Verify span and string_view are trivially copyable

[Mark de Wever via Phabricator via libcxx-commits]

Mordante added a comment.

In general looks good, just want to discuss the supported versions of the tests before approving.



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Comment at: libcxx/test/std/containers/views/trivially_copyable.compile.pass.cpp:8
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
----------------
A bit pedantic, but this is only required in C++23 not in C++20. Can you add a comment. (P2251 was not retroactively applied.)


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Comment at: libcxx/test/std/strings/string.view/trivially_copyable.compile.pass.cpp:9
+
+// <string_view>
+
----------------
jloser wrote:
> Quuxplusone wrote:
> > This surely needs some `// UNSUPPORTED: c++03, c++11, c++14`, but buildkite will tell you for sure.
> > ...Actually, it looks like libc++ supports `string_view` as an extension all the way back to C++03? is that true? So you'll want to use `static_assert(std::is_trivially_copyable<...>::value, "");` below.
> Seems to be the case that `libc++` supports `string_view` all the way back to C++03 oddly enough. Just fixed up the `static_assert`s to play nicely with older modes.
libc++ originally "back-ported" several features to older standards. This gives us occasionally additional maintenance work. Nowadays we no longer back-port features.


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Comment at: libcxx/test/std/strings/string.view/trivially_copyable.compile.pass.cpp:9
+
+// <string_view>
+
----------------
Mordante wrote:
> jloser wrote:
> > Quuxplusone wrote:
> > > This surely needs some `// UNSUPPORTED: c++03, c++11, c++14`, but buildkite will tell you for sure.
> > > ...Actually, it looks like libc++ supports `string_view` as an extension all the way back to C++03? is that true? So you'll want to use `static_assert(std::is_trivially_copyable<...>::value, "");` below.
> > Seems to be the case that `libc++` supports `string_view` all the way back to C++03 oddly enough. Just fixed up the `static_assert`s to play nicely with older modes.
> libc++ originally "back-ported" several features to older standards. This gives us occasionally additional maintenance work. Nowadays we no longer back-port features.
I wonder whether we should disable the test on older versions. This test will fail on MSVC STL in C++11 mode. Looking at cppreference.com I expect other implementations to be trivially copyable from the start.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D111197/new/

https://reviews.llvm.org/D111197