From 9673146cc1e8059c0d0b946ab9df4a46e541b11c Mon Sep 17 00:00:00 2001
From: Marijn Haverbeke <marijnh@gmail.com>
Date: Thu, 19 Mar 2015 14:05:08 +0100
Subject: [PATCH] Verify that property name can be bound to in short-hand
 object pattern properties

Issue #221
---
 acorn.js              | 10 ++++++----
 test/tests-harmony.js |  2 ++
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/acorn.js b/acorn.js
index 00402ed773..7caacb8377 100644
--- a/acorn.js
+++ b/acorn.js
@@ -2492,12 +2492,10 @@
       if (this.options.ecmaVersion >= 6) {
         prop.method = false;
         prop.shorthand = false;
-        if (isPattern || refShorthandDefaultPos) {
+        if (isPattern || refShorthandDefaultPos)
           start = this.currentPos();
-        }
-        if (!isPattern) {
+        if (!isPattern)
           isGenerator = this.eat(tt.star);
-        }
       }
       this.parsePropertyName(prop);
       if (this.eat(tt.colon)) {
@@ -2518,6 +2516,10 @@
       } else if (this.options.ecmaVersion >= 6 && !prop.computed && prop.key.type === "Identifier") {
         prop.kind = "init";
         if (isPattern) {
+          if (this.isKeyword(prop.key.name) ||
+              (this.strict && (isStrictBadIdWord(prop.key.name) || isStrictReservedWord(prop.key.name))) ||
+              (!this.options.allowReserved && this.isReservedWord(prop.key.name)))
+            this.raise(prop.key.start, "Binding " + prop.key.name);
           prop.value = this.parseMaybeDefault(start, prop.key);
         } else if (this.type === tt.eq && refShorthandDefaultPos) {
           if (!refShorthandDefaultPos.start)
diff --git a/test/tests-harmony.js b/test/tests-harmony.js
index 15fcd92c1e..4f2480e12a 100644
--- a/test/tests-harmony.js
+++ b/test/tests-harmony.js
@@ -15508,3 +15508,5 @@ testFail("'use strict'; [...eval] = arr", "Assigning to eval in strict mode (1:1
 testFail("'use strict'; ({eval = defValue} = obj)", "Assigning to eval in strict mode (1:16)", {ecmaVersion: 6});
 
 testFail("[...eval] = arr", "Assigning to eval in strict mode (1:4)", {ecmaVersion: 6, sourceType: "module"});
+
+testFail("function* y({yield}) {}", "Binding yield (1:13)", {ecmaVersion: 6});