Bug in tsi_link_before/after or wrong comment?

[Mostafa Hagog]

tsi_link_before/after in tree-iterator.c has the following problem:
tree-iterator.h says:

  TSI_NEW_STMT,   /* Leave the iterator at the same statement.  */
  TSI_SAME_STMT,  /* Only valid when single statement is added, move
                     iterator to it.  */

And in tree-iterator.c "tsi_link_before" does the following:

  /* Update the iterator, if requested.  */
  switch (mode)
    {
    case TSI_NEW_STMT:  <===========
    case TSI_CONTINUE_LINKING:
    case TSI_CHAIN_START:
      i->ptr = head;
      break;
    case TSI_CHAIN_END:
      i->ptr = tail;
      break;
    case TSI_SAME_STMT: <=========
      if (!cur)
        abort ();
      break;
    }

The marked two lines above does the opposite from what written
in the comment in tree-iterator.h. The same problem exists in
tsi_link_after.

One of two solutions is required: 1. change tsi_link_before/after or, 2.
change the comment.

Since I usually rely on comment I prefer the first solution? any other
suggestions ?