Hello 1nickt,

Maybe you missed understand what I was writing / asking. I am asking what was his target in total. It looks like XY Problem

I never used it they way that you are using it, I would use it like this:

#!/usr/bin/perl
use strict;
use warnings;
use feature 'say';

sub print_timestamp {
    local *_get_formatted_time = sub {
        return $_[0] . uc scalar localtime;
    };
    return _get_formatted_time(@_);
}

say print_timestamp('The time was: ');

__END__

$ perl test.pl
The time was: FRI AUG 25 15:18:08 2017
[download]

Instead of:

#!/usr/bin/perl
use strict;
use warnings;
use feature 'say';

print_timestamp('nigh');
print_timestamp( get_formatted_time() );

sub print_timestamp { say 'The time was ' . shift() }
sub get_formatted_time { return uc scalar localtime }

__END__

$ perl test.pl
The time was nigh
The time was FRI AUG 25 15:20:10 2017
[download]

Update: When you are calling a subroutine withing another subroutine like this:

sub a {
    sub b{
    }
}
[download]

It is basically the same as:

sub a {
}
sub b{
}
[download]

End of Update: So since he is try to test if a subroutine is safe (foo(bar()); # no errors reported - not expected behavior and foo(); # Undefined subroutine reported as expected). Why not simply calling it one by one, since it is the same thing if they are not defined locally?

But I suppose it depends the case. Thanks for sharing other ideas, BR.