All those effects have the same issue, don't they? I've definitely run into situations where I moved from a combinational approach to a control flow based one f

All those effects have the same issue, don't they? I've definitely run into situations where I moved from a combinational approach to a control flow based one for iteration because the combinational approach required multiple closures to borrow the same state mutably. It's almost like there's also still some gap in the borrow checking, but it's not obvious to me how to address that.