http://www.perlmonks.org?node_id=948807


in reply to Surprise: "Can't modify constant item in scalar assignment" [SOLVED]

Did you spot it?
Spotted before reaching the Did you spot it?.

I've been leaving off sigils for more than 15 years. Count your blessing you make that typo so infrequently, you're surprised by the error.

I had to “Google It™”
man perldiag
and search for modify.