diff --git a/src/acorn/src/lookahead.js b/src/acorn/src/lookahead.js
index 8eb3c96ef3..45854478e9 100644
--- a/src/acorn/src/lookahead.js
+++ b/src/acorn/src/lookahead.js
@@ -18,17 +18,19 @@ var STATE_KEYS = [
 ];
 
 pp.getState = function () {
-  var state = {};
+  var state = {}
   for (var i = 0; i < STATE_KEYS.length; i++) {
-    var key = STATE_KEYS[i];
-    state[key] = this[key];
+    var key = STATE_KEYS[i]
+    state[key] = this[key]
   }
-  return state;
+  return state
 };
 
 pp.lookahead = function() {
   var old = this.getState();
-  this.next();
+  this.isLookahead = true
+  this.next()
+  this.isLookahead = false
   var curr = this.getState();
   for (var key in old) this[key] = old[key];
   return curr;
diff --git a/src/acorn/src/tokenize.js b/src/acorn/src/tokenize.js
index fbb0617659..a844b7a2d9 100755
--- a/src/acorn/src/tokenize.js
+++ b/src/acorn/src/tokenize.js
@@ -28,7 +28,7 @@ const pp = Parser.prototype
 // Move to the next token
 
 pp.next = function() {
-  if (this.options.onToken)
+  if (this.options.onToken && !this.isLookahead)
     this.options.onToken(new Token(this))
 
   this.lastTokEnd = this.end