$ perl -MO=Deparse,-p -e 'sub f { @_ } print f(42)'
sub f {
    @_;
}
print(f(42));
-e syntax OK
$ perl -MO=Deparse,-p -e 'sub f { @_ } print+f(42)'
sub f {
    @_;
}
print(f(42));
-e syntax OK
$ perl -MO=Deparse,-p -e 'sub f { @_ } print +f(42)'
sub f {
    @_;
}
print(f(42));
-e syntax OK