$ perl -MO=Deparse -e 'use constant C => "abc"; print C'
use constant ('C', 'abc');
print 'abc';
-e syntax OK
$ perl -MO=Deparse -e 'use constant C => "abc"; print &C'
sub C () { 'abc' }
use constant ('C', 'abc');
print &C;
-e syntax OK