Saxon

On the 12.x branch I'm getting a test failure on an xsl:on-empty test because SignificantItemDetector does not implement the method append(Item) (as opposed to append(Item, Location, int)) which means that a significant item sent to this method may go undetected, leading the "on-empty" instruction to fire when it should not.

I haven't seen an 11.x test that fails for this reason, but the incorrect code is there so a failure could easily occur, and the fix is trivial.