The scalar $hello doesn't exist. The subrouine &hello exists. 
sub hello;
$fn = \&hello;

# ...

[download]

Alternately: 

sub hello;
*fn = *hello;

# ...

[download]

But, either way, your check of $::{'hello'} will fail.

Being right, does not endow the right to be rude; politeness costs nothing.
Being unknowing, is not the same as being stupid.
Expressing a contrary opinion, whether to the individual or the group, is more often a sign of deeper thought than of cantankerous belligerence.
Do not mistake your goals as the only goals; your opinion as the only opinion; your confidence as correctness. Saying you know better is not the same as explaining you know better.

In reply to Re: How can I tell if a function has been forward declared but not yet defined? by dragonchild
in thread How can I tell if a function has been forward declared but not yet defined? by mab

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