$ ./Porting/bisect.pl --start=v5.16.3 --end=v5.26.0 -e '`$^X -Ilib -MO=Deparse -e "use constant X=>3,4; \@x[X]"`=~/\@x\[3, 4\]/ and die' ... commit f815dc14d7c5540dfb5d02d001e0101c6266f281 Author: Father Chrysostomos Date: Sun Jun 30 00:20:33 2013 -0700 Inline list constants These are inlined the same way as 1..5. We have two ops: rv2av | `-- const The const op returns an AV, which is stored in the op tree, and then rv2av flattens it. $ git tag --contains f815dc14d7c5540d ... v5.20.0 ... # *Update:* making sure it's not just the Deparse output that changed... $ ./Porting/bisect.pl --start=v5.19.0 --end=v5.21.0 -e '`$^X -Ilib -MO=Concise -e "use constant X=>3,4; \@x[X]"`=~/entersub/ or die' ... commit f815dc14d7c5540dfb5d02d001e0101c6266f281