Yes, my bad, I meant to reverse the $regex parameters... Corrected testcase:

Code:
alias testcase {
  var %regex = /^$/
  echo -a -- $regex($null,%regex) ; verify regex matches
  hadd -m testcase %regex 42
  echo -a -- $hfind(testcase,$null,0,R) ; <--- bug here; $hfind returns non-numeric value when it should return 1
}