Gas error messages

[Will Newton]

I'm parsing an operand with a custom parser, e.g.:

(define-operand
   ...
   ...
   (handlers (parse "my_parser"))
)

And then in the .opc file:

Parse_my_parser(...)
{
    if (error)
        return "an error occurred";
}

However, when the error message is returned, instead of printing my
error message, as expected, gas spits out:

test.s:28: Error: unrecognized keyword/register name

Am I doing something wrong or is this a bug?