bug#3452: 23.0.94; display

[Chong Yidong <cyd@stupidchicken.com>]

Eli Zaretskii <eliz@gnu.org> writes:

> Btw, I don't understand how these characters are related to
> compositions.  They should not be composed with anything, they always
> stand for themselves.

I didn't know that.  This means there is a bug in either
find_composition (called from composition_compute_stop_pos) or
next_element_from_composition (called from next_element_from_buffer),
because the following code in next_element_from_buffer (xdisp.c:6519) is
triggered for this character:

  if (CHAR_COMPOSED_P (it, IT_CHARPOS (*it), IT_BYTEPOS (*it))
      && next_element_from_composition (it))
    {
       return 1;
    }