It's even worse than that. When $var is emmpty, /$var/ matches anything only if there was no successful match before.

E.g. if you prepend this at the beginning of the script: 

"abc" =~ /a/;

[download]

it suddenly starts outputting "Outside if", because /$var/ runs the last successfully matched regex if there was any (see The empty pattern //). If you don't want this behaviour (and I bet you don't), never use a match with fully dynamic contents. You can change it to /(?:$var)/, so that the pattern doesn't get empty after interpolating the variable.

Update: There probably should be a perlcritic policy forbidding a potentially empty regex match.

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

In reply to Re^2: Issue with matching regex by choroba
in thread Issue with matching regex by KishKishore

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