variable selectors must be paranthesized

lib/less/parser.js

@@ -945,7 +945,9 @@ less.Parser = function Parser(env) {
             selector: function () {
                 var sel, e, elements = [], c, match;
 
-                if (sel = $(this.entities.quoted)) {
+                if ($('(')) {
+                    sel = $(this.entity);
+                    expect(')');
                     return new(tree.Selector)([new(tree.Element)('', sel, i)]);
                 }