[HarfBuzz] bug in `hb_ot_layout_lookup_collect_lookups'

[Werner LEMBERG]

>> However, there are more GSUB lookups, referenced via chained
>> context lookups, AFAICS.  Example: lookup 76, which gets referenced
>> in lookup 4.
>>
>> I presume that this is not intentional behaviour.
>
> It *is* intentional behavior.  What's your exact use case?

Actually, I don't really care about this particular function.  What I
want is to find all glyphs that are involved in substitution, and I
stumbled upon the fact that this substitution is not listed...

However, I see that the mapping result of lookup 76, `glyph242', is
part of the set returned by `hb_ot_layout_lookup_collect_glyphs', so
everything's' fine.  Sorry for the noise.

It would be *great* to have a bit more documentation that mentions
such potential pitfalls :-)


    Werner