checkMergeable = function (parser) {
  var result = [];
  selectorList.forEach(function (item, index, arr) {
    var pos = helpers.propertySearch(arr, item.selector, 'selector');
    if (pos !== index && parser.options.whitelist.indexOf(item.selector) === -1) {
      result = helpers.addUnique(result, {
        'ruleId': parser.rule.name,
        'line': item.line,
        'column': item.column,
        'message': 'Rule `' + item.selector + '` should be merged with the rule on line ' + selectorList[pos].line,
        'severity': parser.severity
      });
    }
  });
  return result;
}
Checks our selector list for mergeable selectors and reports errors where needed

@param {object} parser - The parser object
@returns {array} Array of result objects