rem: _callees.clear();
add: _callers.clear();
context: MakeType1CharstringInterp::Subr::unify(MakeType1CharstringInterp *mcsi){    // clean up callee list    for (int i = 0; i < _callees.size(); i++)	if (!_callees[i].subr) {	    _callees[i] = _callees.back();	    _callees.pop_back();	    i--;	}        if (!_callees.size())	return false;    assert(!_calls.size());    // Find the smallest shared substring.    String substr = _callees[0].charstring(mcsi);    int suboff = 0;    for (int i = 1; i < _callees.size(); i++) {	String substr1 = _callees[i].charstring(mcsi);	const char *d = substr.data() + suboff, *d1 = substr1.data();	const char *dx = substr.data() + substr.length(), *d1x = d1 + substr1.length();	while (dx > d && d1x > d1 && dx[-1] == d1x[-1])	    dx--, d1x--;	suboff = dx - substr.data();    }    substr = substr.substring(Type1Charstring(substr).first_caret_after(suboff));    if (!substr.length())	return false;    for (int i = 0; i < _callees.size(); i++) {	Callee &c = _callees[i];	if (int delta = c.len - substr.length()) {	    c.pos += delta;	    c.len -= delta;	}    }    // otherwise, success    _output_subrno = mcsi->output()->nsubrs();    mcsi->output()->set_subr(_output_subrno, Type1Charstring(substr + "\013"));    // note calls    _callees[0].subr->transfer_nested_calls(_callees[0].pos, _callees[0].len, this);        // adapt callers    String callsubr_string = Type1CharstringGen::callsubr_string(_output_subrno);    for (int i = 0; i < _callees.size(); i++)	if (_callees[i].subr != this) {	    Subr::Callee c = _callees[i];	    //fprintf(stderr, " SUBSTRING %08x:%d+%d\n", c.subr->_csr, c.pos, c.len);	    c.subr->charstring(mcsi)->assign_substring(c.pos, c.len, callsubr_string);	    Subr::bump_date();	    for (int j = 0; j < c.subr->ncalls(); j++)		c.subr->call(j)->change_callees(c.subr, c.pos, c.len, callsubr_string.length());	    assert(!_callees[i].subr);	}    // this subr is no longer "called"/interpolated from anywhere    _callees.clear();    //fprintf(stderr, "Succeeded %x\n", _csr);    return true;}