Scope.

In your first example, $var is declared inside the if block, but exists ONLY within that block. Since it's undefined when program_flow encounters the print statement, strict pumps out the error.

On the other hand, in your example 2, "my $var" is in scope throughout the code you show.

In reply to Re: difference between 'if (condition) { expression;}' and 'expression if (condition)' by ww
in thread difference between 'if (condition) { expression;}' and 'expression if (condition)' by ranjan_jajodia

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