Repeat groups are dropped when transcribing if non-scalar is empty

Created by: natefaubion

macro test {
  rule { { $($name ($args (,) ...)) ... } } => {
    $(function $name ($args (,) ...) {}) ...
  }
}

test {
  foo(a, b)
  bar()
}

function foo(a, b) {
}

You'll notice bar is dropped completely. This is because of patterns.hasMatch and if (allHaveMatch) { ... } in patterns.transcribe. The repeater is empty (so the pattern succeeds), but hasMatch does not consider an empty match set a success when transcribing. Since the allHaveMatch guard only handles the success case, entire repeat groups can be dropped silently. I suppose hasMatch should be smarter.