code: private void checkForDuplicateDefault(List<Stmt.Case> cases) {
  		boolean hasDefault = false;
  		for(int i=0;i!=cases.size();++i) {
  			Stmt.Case c = cases.get(i);
  			if (c.getConditions().size() > 0 && hasDefault) {
  				syntaxError("unreachable code", c);
  			} else if (c.getConditions().size() == 0 && hasDefault) {
  				syntaxError("duplicate default label", c);
  			} else {
  				hasDefault = c.getConditions().size() == 0;
  			}
  		}
  	}
docs: Check whether we have a duplicate default statement, or a case which
  occurs after a default statement (and, hence, is unreachable).
  
  @param cases