This particular error was visible to me, but in many cases other tools may have helped. For example, with emacs I usually never type the entire big word again. The editor has facility to do that for me with few keystrokes.

Using the basic tricks of Perl, such as 'use strict;' and 'use warnings;' can help to avoid such 'basic' errors. 'use diagnostics;' will help too.

The frustration of code not being working take lots of hours for programmers. Getting the basics right at the beginning can make you more confident and productive in long runs.