From 7a2a8d279412919f5a8119dc1de08644ee4cb1b6 Mon Sep 17 00:00:00 2001
From: Rich Harris <richard.a.harris@gmail.com>
Date: Fri, 11 Aug 2017 15:57:47 -0400
Subject: [PATCH] init rhs of for-in loop head with correct scope - fixes #1480

---
 src/ast/nodes/ForInStatement.js                      |  6 +++---
 .../samples/for-loop-head-dependencies/_config.js    |  3 +++
 .../samples/for-loop-head-dependencies/main.js       | 12 ++++++++++++
 3 files changed, 18 insertions(+), 3 deletions(-)
 create mode 100644 test/function/samples/for-loop-head-dependencies/_config.js
 create mode 100644 test/function/samples/for-loop-head-dependencies/main.js

diff --git a/src/ast/nodes/ForInStatement.js b/src/ast/nodes/ForInStatement.js
index 3f0954b8f5c..4735a89f7f8 100644
--- a/src/ast/nodes/ForInStatement.js
+++ b/src/ast/nodes/ForInStatement.js
@@ -6,7 +6,7 @@ import { STRING } from '../values.js';
 export default class ForInStatement extends Statement {
 	initialiseChildren () {
 		this.left.initialise( this.scope );
-		this.right.initialise( this.scope );
+		this.right.initialise( this.scope.parent );
 		this.body.initialiseAndReplaceScope ?
 			this.body.initialiseAndReplaceScope( this.scope ) :
 			this.body.initialise( this.scope );
@@ -14,10 +14,10 @@ export default class ForInStatement extends Statement {
 	}
 
 	initialiseScope ( parentScope ) {
-		this.scope = new Scope( {
+		this.scope = new Scope({
 			parent: parentScope,
 			isBlockScope: true,
 			isLexicalBoundary: false
-		} );
+		});
 	}
 }
diff --git a/test/function/samples/for-loop-head-dependencies/_config.js b/test/function/samples/for-loop-head-dependencies/_config.js
new file mode 100644
index 00000000000..50f9834fbab
--- /dev/null
+++ b/test/function/samples/for-loop-head-dependencies/_config.js
@@ -0,0 +1,3 @@
+module.exports = {
+	description: 'uses parent scope for right-hand-side in for-in statement (#1480)'
+};
\ No newline at end of file
diff --git a/test/function/samples/for-loop-head-dependencies/main.js b/test/function/samples/for-loop-head-dependencies/main.js
new file mode 100644
index 00000000000..d51c8b5bcab
--- /dev/null
+++ b/test/function/samples/for-loop-head-dependencies/main.js
@@ -0,0 +1,12 @@
+function foo() {
+	return ['x'];
+}
+
+const result = [];
+
+for (let i in foo()) {
+	const foo = i;
+	result.push(foo);
+}
+
+assert.deepEqual(result, [0]);
\ No newline at end of file