From 88d7e2012c903ce1858ac51645270050d2026ad0 Mon Sep 17 00:00:00 2001
From: Daniel Tschinder <daniel@tschinder.de>
Date: Sun, 17 Jul 2016 11:08:25 +0200
Subject: [PATCH] Fix lookahead to not add comments to arrays which are not
 cloned (#76)

We do not clone arrays in lookahead() but comments were added
to leading/trailing arrays during lookahead, leading to leak to the next next() call.

Also extracted parsing of JSXSpreadChild to own parse function.
---
 src/plugins/jsx/index.js | 24 ++++++++++++++++--------
 src/tokenizer/index.js   |  3 +--
 2 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/src/plugins/jsx/index.js b/src/plugins/jsx/index.js
index 18b92e9fac..6bc98d396e 100644
--- a/src/plugins/jsx/index.js
+++ b/src/plugins/jsx/index.js
@@ -265,6 +265,18 @@ pp.jsxParseEmptyExpression = function() {
   return this.finishNodeAt(node, "JSXEmptyExpression", this.start, this.startLoc);
 };
 
+// Parse JSX spread child
+
+pp.jsxParseSpreadChild = function() {
+  let node = this.startNode();
+  this.expect(tt.braceL);
+  this.expect(tt.ellipsis);
+  node.expression = this.parseExpression();
+  this.expect(tt.braceR);
+
+  return this.finishNode(node, "JSXSpreadChild");
+};
+
 // Parses JSX expression enclosed into curly brackets.
 
 
@@ -346,15 +358,11 @@ pp.jsxParseElementAt = function(startPos, startLoc) {
 
         case tt.braceL:
           if (this.lookahead().type === tt.ellipsis) {
-            let node = this.startNode();
-            this.next();
-            this.next();
-            node.expression = this.parseExpression();
-            this.expect(tt.braceR);
-            children.push(this.finishNode(node, "JSXSpreadChild"));
-            break;
+            children.push(this.jsxParseSpreadChild());
+          } else {
+            children.push(this.jsxParseExpressionContainer());
           }
-          children.push(this.jsxParseExpressionContainer());
+
           break;
 
         default:
diff --git a/src/tokenizer/index.js b/src/tokenizer/index.js
index 1cd5b5c1fc..f787acb1b5 100644
--- a/src/tokenizer/index.js
+++ b/src/tokenizer/index.js
@@ -166,9 +166,8 @@ export default class Tokenizer {
     if (!this.isLookahead) {
       this.state.tokens.push(comment);
       this.state.comments.push(comment);
+      this.addComment(comment);
     }
-
-    this.addComment(comment);
   }
 
   skipBlockComment() {