The only difference is that when you use @. your Ref(x) wrappers turn into Ref.(x), which is to say they stop actually working as scalarizers (the same problem applies to my suggestion above). Tuple wrappers don’t have this problem, and I’m hoping we’ll get the & syntax to explicitly scalarize even in the presence of @..
Unfortunately, tuple wrappers of non-bits types still allocate on v0.6, so they don’t solve the original problem.
Edit: see also recent broadcast changes (iterate by default), scalar struct, and `@.` - #2 by rdeits