[PATCH] D45163: [Sema] -Wunused-value: diagnose unused std::move() call results.

[Roman Lebedev via Phabricator via cfe-commits]

lebedev.ri added a comment.

In https://reviews.llvm.org/D45163#1055856, @rjmccall wrote:

> Well, we should feel welcome to submit patches to the C++ library implementations, I think.  I can understand why Marshall is waiting to just do this until he gets a comprehensive committee paper,




> but he might consider taking a patch in the meantime.

That has been discussed, and it's not going to happen. Ask him if you want more info.

> But I'm not sure what the rush is if it doesn't change what goes into any concrete release of the compiler + library.

TLDW: `std::move()` is "The Assign Operator (`a = b;`) of RAII". It would be good to diagnose such a problem, and not just rely that some day the std libs will mark it with the attribute.
BTW, even when they do, even for libcxx, it won't be of any immediate use to LLVM, we will need to provide a define (see https://reviews.llvm.org/D45179) to actually enable that attribute, because LLVM is using C++11, not C++17/something...
<insert "not everyone uses clang with libc++" rant>


Repository:
  rC Clang

https://reviews.llvm.org/D45163