[libcxx-commits] [PATCH] D97162: [libcxx] adds std::ranges::swap, std::swappable, and std::swappable_with

[Arthur O'Dwyer via Phabricator via libcxx-commits]

Quuxplusone added inline comments.


================
Comment at: libcxx/test/std/concepts/lang/swappable_with.compile.pass.cpp:593
+
+#ifndef _LIBCPP_HAS_NO_THREADS
+static_assert(!check_swappable_with<std::lock_guard<std::mutex>,
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cjdb wrote:
> ldionne wrote:
> > EricWF wrote:
> > > Can we write these tests in a way that makes them non-threading dependent.
> > > 
> > I don't think so since he's explicitly trying to exercise these types, which aren't provided when `_LIBCPP_HAS_NO_THREADS`. Better would be to have a test-suite version of the macro (to express the fact that the test suite supports being used when threads are not available), but that's for a different patch.
> How about I do that patch just before announcing P0898 is implemented?
Peanut gallery says: Other alternatives include

- test a made-up `struct Immobile` instead of specifically `std::mutex`; we can assume that `std::mutex` is equally immobile

- move tests of `std::mutex`'s own properties into test/std/thread/thread.mutex/ (because if someone were somehow to break the immobility of `std::mutex`, I'd hope that it's the //mutex// tests that fail, not some random concept's tests)

But I have no particular stake in the outcome.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D97162/new/

https://reviews.llvm.org/D97162