Or anytime you're talking about a named subroutine (my $bar = \&foo;) or using the GOTO &SUB form (goto &$bar;). There's still a few places that it's required. Another reason to use the ampersand version is to disable prototype checking, for those subroutines that are evil enough to use it without good reason.
My criteria for good software:
  1. Does it work?
  2. Can someone else come in, make a change, and be reasonably certain no bugs were introduced?

In reply to Re^2: Dereferencing code refs with & vs. ->() by dragonchild
in thread Dereferencing code refs with & vs. ->() by doran

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