You can't pass arrays (or hashes) to subs, only a sequence of zero or more scalars. There is no difference between

f(@a)
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f($a[0], $a[1], $a[2], ...)
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so you can't distinguish

my @empty;
f(@empty)
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f()
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At best, you can use prototypes to change what scalars are passed to a sub.

sub f(;\@)
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f(@a)     # Calls &f(\@a)
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f()       # Calls &f()
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f($x, $y)
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What you want to achieve, however, can't be achieved using prototypes. You'd have to use something like Devel::CallParser.