From e262dcd02133909af8a8bd28f5a5efa9b42d5196 Mon Sep 17 00:00:00 2001
From: Shu-yu Guo <shu@rfrn.org>
Date: Thu, 2 Mar 2017 10:15:56 -0800
Subject: [PATCH] Test that @@unscopables is looked up once for inc/dec. (#869)
---
.../statements/with/unscopables-inc-dec.js | 51 +++++++++++++++++++
1 file changed, 51 insertions(+)
create mode 100644 test/language/statements/with/unscopables-inc-dec.js
diff --git a/test/language/statements/with/unscopables-inc-dec.js b/test/language/statements/with/unscopables-inc-dec.js
new file mode 100644
index 0000000000..e2b12b73f8
--- /dev/null
+++ b/test/language/statements/with/unscopables-inc-dec.js
@@ -0,0 +1,51 @@
+// Copyright (C) 2017 Mozilla Corporation. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-object-environment-records-hasbinding-n
+description: >
+ @@unscopables should be looked up exactly once for inc/dec.
+info: |
+ UpdateExpression : LeftHandSideExpression ++
+ 1. Let lhs be the result of evaluating LeftHandSideExpression.
+
+ GetIdentifierReference ( lex, name, strict )
+ [...]
+ 3. Let exists be ? envRec.HasBinding(name).
+
+ HasBinding ( N )
+ [...]
+ 6. Let unscopables be ? Get(bindings, @@unscopables).
+flags: [noStrict]
+features: [Symbol.unscopables]
+---*/
+
+var unscopablesGetterCalled = 0;
+var a, b, flag = true;
+with (a = { x: 7 }) {
+ with (b = { x: 4, get [Symbol.unscopables]() {
+ unscopablesGetterCalled++;
+ return { x: flag=!flag };
+ } }) {
+ x++;
+ }
+}
+
+assert.sameValue(unscopablesGetterCalled, 1);
+assert.sameValue(a.x, 7);
+assert.sameValue(b.x, 5);
+
+unscopablesGetterCalled = 0;
+flag = true;
+with (a = { x: 7 }) {
+ with (b = { x: 4, get [Symbol.unscopables]() {
+ unscopablesGetterCalled++;
+ return { x: flag=!flag };
+ } }) {
+ x--;
+ }
+}
+
+assert.sameValue(unscopablesGetterCalled, 1);
+assert.sameValue(a.x, 7);
+assert.sameValue(b.x, 3);
--
GitLab