By "remove" I mean mutate the hugr so that the what was a non-local edge becomes many edges threaded through all container nodes between(in the hierarchy sense) the two nodes.

I expect that for many passes, removing all nonlocal edges would make their implementation simpler.

I have in mind a hugr -> hugr transformation that involves converting a non-linear type into a linear type. Linear types cannot be on non-local edges, so it is natural to run "remove-nonlocal-edges" as the first stage.

Likely a "create-nonlocal-edges" pass that, wherever possible, removes non-linear edges into container nodes, would also be useful. One can construct graphs where nearly all edges are removed by such a pass, making the size of Hugr O(nodes) instead of O(nodes^2) although it's unclear what the gains would be in practise.

It may be worthwhile to create both passes at the same time, since their logic is very similar.

• Add a pass to check whether there are any non local edges #1346