tree 3d02afdbce98b18281850df25563e17d0444cf71
parent 36ddeb23df82c1b579318c142ca805ae241085c3
author Ruslan Arutyunyan <ruslan.arutyunyan@intel.com> 1612192329 -0500
committer Copybara-Service <copybara-worker@google.com> 1612517187 -0800

[libc++] Fix for the Bug 41784

Add deleted volatile copy-assignment operator in the most derived atomic
to fix the Bug 41784. The root cause: there is an `operator=(T) volatile`
that has better match than the deleted copy-assignment operator of the base
class when `this` is `volatile`. The compiler sees that right operand of
the assignment operator can be converted to `T` and chooses that path
without taking into account the deleted copy-assignment operator of the
base class.

The current behavior on libstdc++ is different from what we have in libc++.
On the same test compilation fails with libstdc++. Proof: https://godbolt.org/z/nebPYd
(everything is the same except the -stdlib option).

I choose the way with explicit definition of copy-assignment for atomic
in the most derived class. But probably we can fix that by moving
`operator=(T)` overloads to the base class from both specializations.
At first glance, it shouldn't break anything.

Differential Revision: https://reviews.llvm.org/D90968

GitOrigin-RevId: c448ea948c28878735fefec734d8326ca2e4b33a