From e73ea68a99cdebae482c1337709ad2d9d3fd3908 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A9=20Bargull?= <andre.bargull@gmail.com>
Date: Thu, 17 Aug 2017 15:45:27 +0200
Subject: [PATCH] Bug 1383393 - Also ignore null as Symbol.toPrimitive method.
 r=jandem

--HG--
extra : rebase_source : c8a11f2152d5f4c1cb7729d521cbceb43f0be37a
---
 js/src/jsobj.cpp                               |  2 +-
 .../Symbol/toPrimitive-undefined-or-null.js    | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+), 1 deletion(-)
 create mode 100644 js/src/tests/ecma_6/Symbol/toPrimitive-undefined-or-null.js

diff --git a/js/src/jsobj.cpp b/js/src/jsobj.cpp
index ba363baa3cd4..abacceb870ef 100644
--- a/js/src/jsobj.cpp
+++ b/js/src/jsobj.cpp
@@ -3151,7 +3151,7 @@ js::ToPrimitiveSlow(JSContext* cx, JSType preferredType, MutableHandleValue vp)
         return false;
 
     // Step 6.
-    if (!method.isUndefined()) {
+    if (!method.isNullOrUndefined()) {
         // Step 6 of GetMethod. js::Call() below would do this check and throw a
         // TypeError anyway, but this produces a better error message.
         if (!IsCallable(method))
diff --git a/js/src/tests/ecma_6/Symbol/toPrimitive-undefined-or-null.js b/js/src/tests/ecma_6/Symbol/toPrimitive-undefined-or-null.js
new file mode 100644
index 000000000000..f43642e0f89c
--- /dev/null
+++ b/js/src/tests/ecma_6/Symbol/toPrimitive-undefined-or-null.js
@@ -0,0 +1,18 @@
+for (let method of [undefined, null]) {
+    let obj = {
+        [Symbol.toPrimitive]: method,
+        toString: () => "pass",
+    };
+    assertEq("" + obj, "pass");
+}
+
+for (let method of [true, false, 0, 123, "", "abc", Symbol(), {}]) {
+    let obj = {
+        [Symbol.toPrimitive]: method,
+        toString: () => "pass",
+    };
+    assertThrowsInstanceOf(() => "" + obj, TypeError);
+}
+
+if (typeof reportCompare === "function")
+    reportCompare(0, 0);