"One additional detail is that a new array (actually list) is always created."

That sounds like you're referring to map; if so, that changed in 5.8.1 (over a decade ago).

From perl581delta: Miscellaneous Enhancements:

"map is now context aware, and will not construct a list if called in void context."

I don't follow what you're trying to show with that code in the anonymous block. What does the "it" in "So, it would really be more like:" refer to? Is the anonymous block supposed to be a do {...} block? And $newarray is probably a typo.