At #900 we've already decided that text-decoration is considered part of the text, so it will be clipped as well.
text-emphasis should also be treated the same.
There are currently some issues with both Safari and Firefox, see examples:
https://codepen.io/yisi/pen/zYVJqyR?editors=0100
Safari TP 202
Looks like it's dropped U+FE0F (VS16)

Firefox

cc @smfr @nt1m