$ perl -wle 'print (-2)**2'
    print (...) interpreted as function at -e line 1.
    Useless use of exponentiation (**) in void context at -e line 1.
    -2
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Just like any other function, if the function name is followed by a left paren, it's taken as the start of the argument list. print (-2)**2 is parsed as (print (-2)) ** 2. This is even documented. From perldoc print:

Also be careful not to follow the
print keyword with a left parenthesis unless you
want the corresponding right parenthesis to termi-
nate the arguments to the print--interpose a "+"
or put parentheses around all the arguments.
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Abigail

Good catch, I should have used -w... sigh

Arien mumbles something about how anybody can forget to put in switches now and then. ( -f ;-)

— Arien

Try perl -e '$v = 2; print -$v ** 2;'

This the use of unary negation that is the subject of the thread.

But if you look at the problem that Arien posed, the answer doesn't just have the incorrect sign, it's also got the wrong magnitude.

--
Tommy
Too stupid to live.
Too stubborn to die.