This is related to loop fusion, e.g.:

https://julialang.org/blog/2017/01/moredots

I don't have the citation but I believe they mentioned that the Chapel language also does this. Rather than materializing intermediate arrays, it just does everything element-wise in one pass.

I think this optimization may make sense in some cases that arise in practice, but probably not very many. There are a lot of other things that need to be fixed with the shell first.