How to return a reference to a slice of an array in Chapel?

I'm trying to return a reference to a slice of an array , but am getting the following compile-time error (where the offending line is in slice

test.chpl:9: error: illegal expression to return by ref

Returning the full array works fine, as does taking a reference to a slice in the main program.

Is there a correct way to return a ref to a slice? Thanks in advance!

record R {
  var A : [0.. #10] int;

  proc full() ref {
    return A;
  }

  proc slice() ref {
    return A[0.. #5];
  }
}

var r : R;
ref x1 = r.full();
ref x2 = r.slice();
ref x3 = x1[0.. #5];

Just for completeness :

chpl Version 1.16.0 pre-release (2659cc6)