Can anyone tell me why the following code:

  .sub _main
        .local PerlUndef val

        val = new PerlUndef
        _foo("bar", val)

        end
  .end

  .sub _foo
        .param string v1
        .param pmc v2

        .pcc_begin_return
        .return 1
        .pcc_end_return
  .end

Would produce the following output:

  cog:~/parrot test.imc
  wrong param count
          in file '(unknown file)' near line -1

It seems to be related to passing the PerlUndef as the seoncd
parameter...