Hmm. I was looking at this prior to my previous post. Notice that:
do { my $i = 16; ${ \(++$i) } = 'fred'; $i };  # returns 'fred'

do { my $i = 16; ${ \($i++) } = 'fred'; $i };  # returns 17

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Maybe the warning you got is due to how Perl parses the preincrement assignment expression? I don't know.

In reply to Re^4: Pre vs Post Incrementing variables by repellent
in thread Pre vs Post Incrementing variables by SavannahLion

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