empty returns no longer return null

lib/lexer.js

@@ -418,12 +418,12 @@
     Lexer.prototype.tagParameters = function() {
       var i, tok;
       if (this.tag() !== ')') {
-        return null;
+        return;
       }
       i = this.tokens.length;
       while (true) {
         if (!(tok = this.tokens[--i])) {
-          return null;
+          return;
         }
         switch (tok[0]) {
           case 'IDENTIFIER':