Changing the error message from subset type violation

I was just playing around with using a "subset" to restrict a
string to a set of allowed values:

  subset Monster of Str where * eq any( << godzilla mothera blob
tingler grendel minotaur >> );

  my Monster $thingie;
  $thingie = 'grendel';  # accepts this as expected

  $thingie = 'nada';     # fails as expected, with message:
  # Type check failed in assignment to $thingie; expected Monster but
got Str ("nada")

I was wondering if there's some way to replace that error message
with a better one.  If there's only a half dozen allowed values
I'd want to tell the user something like

  "The string nada is note one of the allowed values
   godzilla mothera blob tingler grendel minotaur"

I keep thinking there should be a form of where with a CATCH that
should work, but I don't see how to do it.

• Changing the error message from subset type violation by Joseph Brenner
• Re: Changing the error message from subset type violation by yary