diff --git a/src/tokenizer/index.js b/src/tokenizer/index.js
index c2248cb4fb..c8b06ef0d6 100644
--- a/src/tokenizer/index.js
+++ b/src/tokenizer/index.js
@@ -56,7 +56,9 @@ export default class Tokenizer {
   // Move to the next token
 
   next() {
-    this.state.tokens.push(new Token(this.state));
+    if (!this.isLookahead) {
+      this.state.tokens.push(new Token(this.state));
+    }
 
     this.state.lastTokEnd = this.state.end;
     this.state.lastTokStart = this.state.start;
@@ -102,9 +104,13 @@ export default class Tokenizer {
 
   lookahead() {
     var old = this.state;
-    this.state = old.clone();
+    this.state = old.clone(true);
+
+    this.isLookahead = true;
     this.next();
-    var curr = this.state.clone();
+    this.isLookahead = false;
+
+    var curr = this.state.clone(true);
     this.state = old;
     return curr;
   }
@@ -172,8 +178,10 @@ export default class Tokenizer {
       range: [start, end]
     };
 
-    this.state.tokens.push(comment);
-    this.state.comments.push(comment);
+    if (!this.isLookahead) {
+      this.state.tokens.push(comment);
+      this.state.comments.push(comment);
+    }
     this.addComment(comment);
   }
 
diff --git a/src/tokenizer/state.js b/src/tokenizer/state.js
index d5099ccaeb..4765017de3 100644
--- a/src/tokenizer/state.js
+++ b/src/tokenizer/state.js
@@ -70,11 +70,15 @@ export default class State {
     return new Position(this.curLine, this.pos - this.lineStart);
   }
 
-  clone() {
+  clone(skipArrays?) {
     var state = new State;
     for (var key in this) {
       var val = this[key];
-      if (Array.isArray(val)) val = val.slice();
+
+      if (!skipArrays && Array.isArray(val)) {
+        val = val.slice();
+      }
+
       state[key] = val;
     }
     return state;