[PATCH] D137205: [clang-tidy] Add performance-unnecessary-copy-on-last-use check

[Fabian Keßler via Phabricator via cfe-commits]

Febbe added a comment.

In D137205#4047828 <https://reviews.llvm.org/D137205#4047828>, @Skylion007 wrote:

> I am trying this in the wild and getting some false positives where it tries to call std::move inside loop conditions and in the boolean condition for an if statement. Stuff like:
>
>   if (SmartPtr new_ptr = steal_ptr(std::move(old_ptr))) {
>     ...
>   }
>   else {
>     return old_ptr; // Now it's moved from and invalid
>   }
>
> Also this can be happen for similar boolean conditionals in while, for, do while loops.
>
> Interestingly, the logic in bugprone-use-after-move flags this error so maybe we can reuse some of that logic to detect bad std::move.

Does this only happen on "init-statements" of while/if/switch?
And thanks for the catch, I'll take a look into it as soon I have more time.

Btw. I've oriented myself at the "bugprone-use-after-move" check, but simply inverting it does not work here.


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https://reviews.llvm.org/D137205