From d1d95e0e494c0630591f04e41bb82bb94d45a413 Mon Sep 17 00:00:00 2001
From: Sebastian McKenzie <sebmck@gmail.com>
Date: Thu, 28 May 2015 10:04:32 -0400
Subject: [PATCH] check LHS of ForIn/ForOfStatement for constants - closes
 #1630

---
 .../transformers/es6/constants.js               | 17 ++++++++++++++---
 src/babel/traversal/scope/index.js              |  7 +++++++
 src/babel/types/alias-keys.json                 |  4 ++--
 .../es6.constants/no-for-in/actual.js           |  3 +++
 .../es6.constants/no-for-in/options.json        |  3 +++
 5 files changed, 29 insertions(+), 5 deletions(-)
 create mode 100644 test/core/fixtures/transformation/es6.constants/no-for-in/actual.js
 create mode 100644 test/core/fixtures/transformation/es6.constants/no-for-in/options.json

diff --git a/src/babel/transformation/transformers/es6/constants.js b/src/babel/transformation/transformers/es6/constants.js
index 54021f8058..5c72905b76 100644
--- a/src/babel/transformation/transformers/es6/constants.js
+++ b/src/babel/transformation/transformers/es6/constants.js
@@ -1,12 +1,12 @@
 import * as messages from "../../../messages";
 
-export function AssignmentExpression(node, parent, scope, file) {
-  var ids = this.getBindingIdentifiers();
+function checkPath(path, file) {
+  var ids = path.getBindingIdentifiers();
 
   for (var name in ids) {
     var id = ids[name];
 
-    var binding = scope.getBinding(name);
+    var binding = path.scope.getBinding(name);
 
     // no binding exists
     if (!binding) continue;
@@ -23,8 +23,19 @@ export function AssignmentExpression(node, parent, scope, file) {
   }
 }
 
+export function AssignmentExpression(node, parent, scope, file) {
+  checkPath(this, file);
+}
+
 export { AssignmentExpression as UpdateExpression };
 
 export function VariableDeclaration(node) {
   if (node.kind === "const") node.kind = "let";
 }
+
+export function ForXStatement(node, parent, scope, file) {
+  var left = this.get("left");
+  if (left.isIdentifier() || left.isPattern()) {
+    checkPath(left, file);
+  }
+}
diff --git a/src/babel/traversal/scope/index.js b/src/babel/traversal/scope/index.js
index 92fc9cc6c1..e96756c6b7 100644
--- a/src/babel/traversal/scope/index.js
+++ b/src/babel/traversal/scope/index.js
@@ -46,6 +46,13 @@ var programReferenceVisitor = {
     }
   },
 
+  ForXStatement(node, parent, scope, state) {
+    var left = this.get("left");
+    if (left.isPattern() || left.isIdentifier()) {
+      scope.registerConstantViolation(left);
+    }
+  },
+
   Scopable(node, parent, scope, state) {
     for (var name in scope.bindings) {
       state.references[name] = true;
diff --git a/src/babel/types/alias-keys.json b/src/babel/types/alias-keys.json
index 07fc4000e9..bff7f8134f 100644
--- a/src/babel/types/alias-keys.json
+++ b/src/babel/types/alias-keys.json
@@ -44,8 +44,8 @@
   "ClassDeclaration": ["Scopable", "Class", "Statement", "Declaration"],
   "ClassExpression":  ["Scopable", "Class", "Expression"],
 
-  "ForOfStatement": ["Scopable", "Statement", "For", "Loop"],
-  "ForInStatement": ["Scopable", "Statement", "For", "Loop"],
+  "ForOfStatement": ["Scopable", "Statement", "For", "Loop", "ForXStatement"],
+  "ForInStatement": ["Scopable", "Statement", "For", "Loop", "ForXStatement"],
   "ForStatement":   ["Scopable", "Statement", "For", "Loop"],
 
   "ObjectPattern":     ["Pattern"],
diff --git a/test/core/fixtures/transformation/es6.constants/no-for-in/actual.js b/test/core/fixtures/transformation/es6.constants/no-for-in/actual.js
new file mode 100644
index 0000000000..46c5fbbc10
--- /dev/null
+++ b/test/core/fixtures/transformation/es6.constants/no-for-in/actual.js
@@ -0,0 +1,3 @@
+const MULTIPLIER = 5;
+
+for (MULTIPLIER in arr);
diff --git a/test/core/fixtures/transformation/es6.constants/no-for-in/options.json b/test/core/fixtures/transformation/es6.constants/no-for-in/options.json
new file mode 100644
index 0000000000..3eed8a7760
--- /dev/null
+++ b/test/core/fixtures/transformation/es6.constants/no-for-in/options.json
@@ -0,0 +1,3 @@
+{
+  "throws": "\"MULTIPLIER\" is read-only"
+}