Passing reference in sync calls should also be considered unsafe

[Heap-Hop]

Thank you for creating this great crate!

I noticed that passing a reference in a sync call might cause a dangling pointer because the reference on the Go side might be saved, while it could have already been dropped on the Rust side.

Given that the design goal of this crate is to pursue extreme performance, this might be expected. However, I am wondering if synchronous calls should also be considered unsafe, similar to asynchronous calls.

Please have a look or try this simple example: https://github.com/Heap-Hop/rust2go/tree/unsafe_sync

https://github.com/Heap-Hop/rust2go/commit/9734b2429d9d00e2be8e03ff89c72d17c5e76706#diff-8aa8e83ff3b2189fd6397149a7b274f82daede3923191a3d0409f72a2f8bb78fR36

If I missed any mention of similar issues in the documentation, please correct me. Thanks again.

[ihciah]

Yes it is.

There are 2 responsibites, one is to ensure params not dropped when go executing user's function, and another one is to make sure borrowed parameters not outlive the function.

I think the first one is for rust, so not taking ownership and drop the future is not safe. The second one is for golang side to obey. Since there's no unsafe marker in golang, users must ensure it by themself. We cannot push this responsibility to rust because golang not having unsafe marker, it is not rust side's job.