anchor.diff:      return null;
     }
   
  -  EquationMember _applyMultiplicand(double m) {
  +  Expression _applyMultiplicand(double m) {
       List<Term> newTerms = terms.fold(
         new List<Term>(),
         (List<Term> list, Term term) {
  
positive.code:   }
  
    @override
    EquationMember operator /(EquationMember m) {
      if (!m.isConstant) {
        throw new ParserException(
            'The divisor was not a constant expression', <EquationMember>[this, m]);
  
negative.code:   }
  
    @override
    Expression operator *(EquationMember m) {
      _Multiplication args = _findMulitplierAndMultiplicand(m);
  
      if (args == null) {
  