At the all-hands, we talked about aggregate initializers vs. initializing an aggregate field-by-field, and then having some kind of "marker instruction" saying "now all fields have been initialized, go get it". I was doubtful about what this would even mean in terms of semantics, but now we have an example: I think this would help with https://github.com/solson/miri/issues/633.
Cc @eddyb @nikomatsakis
interesting, so we would want to even keep it in
instead of it being removed like some borrowck-only constructs are
yeah this seems like it could help tell the optimizer when it can rely on certain invariants