You can take a reference to a sub that doesn't exist. It's much like forward declarations of subs:

package Foo;

sub bar; # we'll define that later

\&bar;   # same effect
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In fact, that's how AutoLoader works - it loads a modules autosplit.ix file which contain forward declarations of subs to be loaded. The CODE slot of the typeglob is allocated, but it's empty. That's why calling such a sub AutoLoader's AUTOLOAD is called, which requires the sub's source file on the fly.

_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}