Umm.  Cryptic, yes

hb-face.cc:650: error: ISO C++ says that these are ambiguous, even though the worst conversion for the first is better than the worst conversion for the second:
hb-vector.hh:81: note: candidate 1: Type& hb_vector_t<Type, PreallocedCount>::operator[](unsigned int) [with Type = hb_face_builder_data_t::table_entry_t, unsigned int PreallocedCount = 32u]
hb-face.cc:650: note: candidate 2: operator[](T*, int) <built-in>
1 file changed