1 files changed, 85 insertions, 0 deletions
diff --git a/js/src/tests/non262/expressions/trailing_comma_arguments.js b/js/src/tests/non262/expressions/trailing_comma_arguments.js
new file mode 100644
index 0000000000..612fd46a13
--- /dev/null
+++ b/js/src/tests/non262/expressions/trailing_comma_arguments.js
@@ -0,0 +1,85 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Trailing comma in Arguments production.
+
+// 12.3 Left-Hand-Side Expressions
+// Arguments[Yield]:
+//   ()
+//   ( ArgumentList[?Yield] )
+//   ( ArgumentList[?Yield] , )
+
+
+function argsLength() {
+    return {value: arguments.length};
+}
+function sum(...rest) {
+    return {value: rest.reduce((a, c) => a + c, 0)};
+}
+
+function call(f, argList) {
+    return eval(`(${f}(${argList})).value`);
+}
+
+function newCall(F, argList) {
+    return eval(`(new ${F}(${argList})).value`);
+}
+
+function superCall(superClass, argList) {
+    return eval(`(new class extends ${superClass} {
+        constructor() {
+            super(${argList});
+        }
+    }).value`);
+}
+
+// Ensure the correct number of arguments is passed.
+for (let type of [call, newCall, superCall]) {
+    let test = type.bind(null, "argsLength");
+
+    assertEq(test("10, "), 1);
+    assertEq(test("10, 20, "), 2);
+    assertEq(test("10, 20, 30, "), 3);
+    assertEq(test("10, 20, 30, 40, "), 4);
+
+    assertEq(test("...[10, 20], "), 2);
+    assertEq(test("...[10, 20], 30, "), 3);
+    assertEq(test("...[10, 20], ...[30], "), 3);
+}
+
+// Ensure the arguments themselves are passed correctly.
+for (let type of [call, newCall, superCall]) {
+    let test = type.bind(null, "sum");
+
+    assertEq(test("10, "), 10);
+    assertEq(test("10, 20, "), 30);
+    assertEq(test("10, 20, 30, "), 60);
+    assertEq(test("10, 20, 30, 40, "), 100);
+
+    assertEq(test("...[10, 20], "), 30);
+    assertEq(test("...[10, 20], 30, "), 60);
+    assertEq(test("...[10, 20], ...[30], "), 60);
+}
+
+// Error cases.
+for (let type of [call, newCall, superCall]) {
+    let test = type.bind(null, "f");
+
+    // Trailing comma in empty arguments list.
+    assertThrowsInstanceOf(() => test(","), SyntaxError);
+
+    // Leading comma.
+    assertThrowsInstanceOf(() => test(", a"), SyntaxError);
+    assertThrowsInstanceOf(() => test(", ...a"), SyntaxError);
+
+    // Multiple trailing comma.
+    assertThrowsInstanceOf(() => test("a, , "), SyntaxError);
+    assertThrowsInstanceOf(() => test("...a, , "), SyntaxError);
+
+    // Elision.
+    assertThrowsInstanceOf(() => test("a, , b"), SyntaxError);
+}
+
+if (typeof reportCompare === "function")
+    reportCompare(0, 0);