Comment 3 for bug 702403

  The bug cannot be reproduced with the reported test case for the main
  5.3 tree because the backported fix for bug 59696 masks the
  problem that causes the crash in the mentioned test case. It's not
  clear weather this fix masks this problem in all possible cases.

  Anyway the patch for bug 698882 introduced some inconsistent data
  structures that could contain indirect references to deleted object.
  It happened when two Item_equal objects were merged and the Item_field
  list of the second object was joined to such list of the first object.
  This operation required adjustment of the backward pointers in
  Item fields from the joined list. However the adjustment was missing
  and this caused crashes in the tree for mwl#128.

  That's why I decided to apply the fix to 5.3 too.