From 7786487bbe0c5ee43a287dfb820582cf9267d12f Mon Sep 17 00:00:00 2001
From: Tooru Fujisawa <arai_a@mac.com>
Date: Tue, 3 Feb 2015 14:59:32 +0900
Subject: [PATCH] Bug 1096377 - Disallow duplicated parameter in arrow
 functions. r=jorendorff

---
 js/src/frontend/Parser.cpp                        |  2 +-
 .../tests/ecma_6/Function/arrow-has-duplicated.js | 15 +++++++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)
 create mode 100644 js/src/tests/ecma_6/Function/arrow-has-duplicated.js

diff --git a/js/src/frontend/Parser.cpp b/js/src/frontend/Parser.cpp
index 23a196dcb2ac..864c967cf391 100644
--- a/js/src/frontend/Parser.cpp
+++ b/js/src/frontend/Parser.cpp
@@ -1624,7 +1624,7 @@ Parser<ParseHandler>::functionArguments(FunctionSyntaxKind kind, FunctionType ty
         bool hasDefaults = false;
         Node duplicatedArg = null();
         Node list = null();
-        bool disallowDuplicateArgs = false;
+        bool disallowDuplicateArgs = kind == Arrow;
 
         if (type == Getter) {
             report(ParseError, false, null(), JSMSG_ACCESSOR_WRONG_ARGS, "getter", "no", "s");
diff --git a/js/src/tests/ecma_6/Function/arrow-has-duplicated.js b/js/src/tests/ecma_6/Function/arrow-has-duplicated.js
new file mode 100644
index 000000000000..19096ebf885a
--- /dev/null
+++ b/js/src/tests/ecma_6/Function/arrow-has-duplicated.js
@@ -0,0 +1,15 @@
+// Make sure duplicated name is allowed in non-strict.
+function f0(a, a) {
+}
+
+// SyntaxError should be thrown if arrow function has duplicated name.
+assertThrowsInstanceOf(() => eval(`
+(a, a) => {
+};
+`), SyntaxError);
+assertThrowsInstanceOf(() => eval(`
+(a, ...a) => {
+};
+`), SyntaxError);
+
+reportCompare(0, 0, 'ok');