for (size_t i = 0; i != insertion.size(); ++i) {
pos_type end = insertion[i].size();
for (pos_type j = 0; j != end; ++j) {
+ // skip insets
+ if (insertion[i].isInset(j))
+ continue;
char_type const c = insertion[i].getChar(j);
if (!e->encodable(c)) {
// do not track deletion