Nim/tests/arc/topt_refcursors.nim

discard """
  output: ''''''
  cmd: '''nim c --gc:arc --expandArc:traverse --hint:Performance:off $file'''
  nimout: '''--expandArc: traverse

var it_cursor = root
block :tmp:
  while (
    not (it_cursor == nil)):
    echo [it_cursor.s]
    it_cursor = it_cursor.ri
var jt_cursor = root
block :tmp_1:
  while (
    not (jt_cursor == nil)):
    let ri_1_cursor = jt_cursor.ri
    echo [jt_cursor.s]
    jt_cursor = ri_1_cursor
-- end of expandArc ------------------------'''
"""

type
  Node = ref object
    le, ri: Node
    s: string

proc traverse(root: Node) =
  var it = root
  while it != nil:
    echo it.s
    it = it.ri

  var jt = root
  while jt != nil:
    let ri = jt.ri
    echo jt.s
    jt = ri

traverse(nil)

# XXX: This optimization is not sound