Using strict as well as warnings would probably help.
Looking at perldiag at the entry for the warning which is closest what is quoted by the OP, using strict would not help. In fact, it can only happen with lexicals - it shouldn't happen with package variables.

In reply to Re^2: Help with 'use Warnings' please? by JavaFan
in thread Help with 'use Warnings' please? by wa4otj

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