I know the whole unwind safety is more of a lint than a real contract, but I feel that its present form isn't really useful (as it doesn't seem to be consistent even in std).
As far as I know, Weak is only different from Rc because no one has bothered to manually declare the UnwindSafe/RefUnwindSafe impls.
I absolutely agree that unwind safety isn't useful - I'd recommend just applying
AssertUnwindSafe whenever necessary and ignoring it as much as possible.
That's what I tought. I don't think fixing it via PR makes sense, I'd rather use this example as an argument for deprecating.