It's quite simple: Using a my variable without having first executed the my is a bug. By braking that rule, you break the "fourth wall" between the promised behaviour of my and its optimised implementation.

my variables are created at compile time. Executing a my places a directive on the stack that will get executed on scope exit. The directive causes the variable to be cleared (if possible) or replaced (if a reference keeps it alive).

If you want a static variable, use state.

In reply to Re: A curious case of of my() by ikegami
in thread A curious case of of my() by fleetingflicker

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