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markus2012

Can't you think of it as still being scoped - just more fine grained? Pieces of structs can be borrow checked (what you are using) instead of the whole struct?

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We already do that. (See LoanPath in the compiler.) It's not a problem of reasoning about the structure of data--it's a problem of defining a notion of "overlapping control flow regions" that is simultaneously intuitive to the programmer, easy to compute, sound, and satisfies the ordering constraints we need (well-defined GLB, LUB, and partial order).

Is there a real trade off between intuitive and easy to compute, versus sound and satisfies the ordering constraints, or can you just compute the most precise sound solution?

Maybe; it's unclear. The hardest part is getting the GLB/LUB/subtyping right.

Yes, it's a scope, but not a lexical scope, hence the name :)

I believe that 'borrowing part of a struct' is a different extension to the system, actually, though maybe they'll be put together. I haven't been involved in the pre-RFC myself.

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