I'd probably respond that map in void context is not a good idea, because it's simply not what the function was supposed to mean and that I'm not sure whether it would provide the same context to the function, whether the void context of the map propagates into the block.

I think it would be better to check ask what does

my @dates = map {localtime($_)} (0,1000,2000);
print join("\n", @dates);
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print. I bet a lot of people would respond that it would print three lines with formatted dates 1970-01-01 with slightly different times.