Maybe. It doesn't loop even on 5.16.3 which is the oldest Perl easily available to me.

Update: 5.10.1 neither.

Update2: It loops in 5.6.2!

map{substr$_->[0],$_->[1]||0,1}[\*||{},3],[[]],[ref qr-1,-,-1],[{}],[sub{}^*ARGV,3]

In reply to Re^5: Is it safe to use external strings for regexes? (infinite loops) by choroba
in thread Is it safe to use external strings for regexes? by stevieb

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