1 files changed, 41 insertions, 0 deletions
diff --git a/js/src/tests/non262/destructuring/rest-parameter-function-length.js b/js/src/tests/non262/destructuring/rest-parameter-function-length.js
new file mode 100644
index 0000000000..5924e799ad
--- /dev/null
+++ b/js/src/tests/non262/destructuring/rest-parameter-function-length.js
@@ -0,0 +1,41 @@
+/* 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/. */
+
+// Ensure function length is set correctly when a destructuring rest parameter
+// is present.
+
+assertEq(function(...[]) {}.length, 0);
+assertEq(function(...[a]) {}.length, 0);
+assertEq(function(...[a = 0]) {}.length, 0);
+assertEq(function(...{}) {}.length, 0);
+assertEq(function(...{p: a}) {}.length, 0);
+assertEq(function(...{p: a = 0}) {}.length, 0);
+assertEq(function(...{a = 0}) {}.length, 0);
+
+assertEq(function(x, ...[]) {}.length, 1);
+assertEq(function(x, ...[a]) {}.length, 1);
+assertEq(function(x, ...[a = 0]) {}.length, 1);
+assertEq(function(x, ...{}) {}.length, 1);
+assertEq(function(x, ...{p: a}) {}.length, 1);
+assertEq(function(x, ...{p: a = 0}) {}.length, 1);
+assertEq(function(x, ...{a = 0}) {}.length, 1);
+
+assertEq(function(x, y, ...[]) {}.length, 2);
+assertEq(function(x, y, ...[a]) {}.length, 2);
+assertEq(function(x, y, ...[a = 0]) {}.length, 2);
+assertEq(function(x, y, ...{}) {}.length, 2);
+assertEq(function(x, y, ...{p: a}) {}.length, 2);
+assertEq(function(x, y, ...{p: a = 0}) {}.length, 2);
+assertEq(function(x, y, ...{a = 0}) {}.length, 2);
+
+assertEq(function(x, y = 0, ...[]) {}.length, 1);
+assertEq(function(x, y = 0, ...[a]) {}.length, 1);
+assertEq(function(x, y = 0, ...[a = 0]) {}.length, 1);
+assertEq(function(x, y = 0, ...{}) {}.length, 1);
+assertEq(function(x, y = 0, ...{p: a}) {}.length, 1);
+assertEq(function(x, y = 0, ...{p: a = 0}) {}.length, 1);
+assertEq(function(x, y = 0, ...{a = 0}) {}.length, 1);
+
+if (typeof reportCompare === "function")
+    reportCompare(0, 0);