[libcxx-commits] [libcxx] [libc++] Implement std::move_only_function (P0288R9) (PR #94670)

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huixie90 wrote:

There is a discussion on the `function_ref` patch about the signature `_ArgTypes` of this function pointer .  If the user has a function that takes PR value, e.g. `move_only_function<void(Foo)>` ,  if Foo's move ctor is not cheap , e.g. not trivial, or not inline, we could end of calling the move ctor unnecessarily 1 more time.

https://github.com/llvm/llvm-project/pull/94670