Go is changing the semantics of its for loops and the user is not a fan of this - at least in the subtleties. Most people, from what I can tell, are very much for this change. And note, Go is introducing quite sophisticated backwards compatibility features to avoid changing semantics for programs that are need the old behaviour.

Go loops define pointers for scope-defined variables at the loop, rather than iteration, level, so there's a common "gotcha" where you intern a pointer to access it outside of the loop (such as pushing it onto an array), and then discover that its value is clobbered by subsequent runs of the loop. There is a proposal to change this, since it's a source of confusion and bugs, particularly when `range`ing over pointers.

What the code snippet demonstrates is that, for a contrived scenario, the proposal in question also creates an unexpected result when you expect pointers to remain stable between loop iterations. To be honest, I can't think of any time where this would be an issue for me (as opposed to writing `foo := foo`); Go has quite a bit of cognitive friction in its loop semantics, so anything to reduce unexpected behavior is welcome to my mind.

In short, the new proposed Go semantics automatically declared an inside variable which has the same name as the iteration variable "I". So the inside "I" is not the iteration variable "I".