Oh interesting.

In java land the fact that you effectively don't have pointers but rather everything is an object reference, this ends up not being an issue.

I wonder if the WASM limitation is related to the fact that JavaScript has pretty similar semantics with no real concept of a "pointer". It means to get that interior pointer, you'd need to also introduce that concept into the GC of browsers which might be a bit harder since it'd only be for WASM.