1 files changed, 49 insertions, 0 deletions
diff --git a/js/src/tests/test262/language/arguments-object/cls-expr-meth-args-trailing-comma-undefined.js b/js/src/tests/test262/language/arguments-object/cls-expr-meth-args-trailing-comma-undefined.js
new file mode 100644
index 0000000000..b109368ca1
--- /dev/null
+++ b/js/src/tests/test262/language/arguments-object/cls-expr-meth-args-trailing-comma-undefined.js
@@ -0,0 +1,49 @@
+// This file was procedurally generated from the following sources:
+// - src/arguments/args-trailing-comma-undefined.case
+// - src/arguments/default/cls-expr-meth.template
+/*---
+description: A trailing comma after undefined should not increase the arguments.length (class expression method)
+esid: sec-arguments-exotic-objects
+flags: [generated]
+info: |
+    9.4.4 Arguments Exotic Objects
+
+    Most ECMAScript functions make an arguments object available to their code. Depending upon the
+    characteristics of the function definition, its arguments object is either an ordinary object
+    or an arguments exotic object.
+
+    Trailing comma in the arguments list
+
+    Left-Hand-Side Expressions
+
+    Arguments :
+        ( )
+        ( ArgumentList )
+        ( ArgumentList , )
+
+    ArgumentList :
+        AssignmentExpression
+        ... AssignmentExpression
+        ArgumentList , AssignmentExpression
+        ArgumentList , ... AssignmentExpression
+---*/
+
+
+var callCount = 0;
+var C = class {
+  method() {
+    assert.sameValue(arguments.length, 2);
+    assert.sameValue(arguments[0], 42);
+    assert.sameValue(arguments[1], undefined);
+    callCount = callCount + 1;
+  }
+};
+
+C.prototype.method(42, undefined,);
+
+// Stores a reference `ref` for case evaluation
+var ref = C.prototype.method;
+
+assert.sameValue(callCount, 1, 'method invoked exactly once');
+
+reportCompare(0, 0);