$ 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