1 files changed, 38 insertions, 0 deletions
diff --git a/js/src/tests/test262/language/statements/async-function/dflt-params-trailing-comma.js b/js/src/tests/test262/language/statements/async-function/dflt-params-trailing-comma.js
new file mode 100644
index 0000000000..2a8141f351
--- /dev/null
+++ b/js/src/tests/test262/language/statements/async-function/dflt-params-trailing-comma.js
@@ -0,0 +1,38 @@
+// |reftest| async
+// This file was procedurally generated from the following sources:
+// - src/function-forms/dflt-params-trailing-comma.case
+// - src/function-forms/default/async-func-decl.template
+/*---
+description: A trailing comma should not increase the respective length, using default parameters (async function declaration)
+esid: sec-async-function-definitions
+features: [async-functions]
+flags: [generated, async]
+info: |
+    14.6 Async Function Definitions
+
+    AsyncFunctionDeclaration :
+      async function BindingIdentifier ( FormalParameters ) { AsyncFunctionBody }
+
+
+    Trailing comma in the parameters list
+
+    14.1 Function Definitions
+
+    FormalParameters[Yield, Await] : FormalParameterList[?Yield, ?Await] ,
+---*/
+
+
+var callCount = 0;
+
+// Stores a reference `ref` for case evaluation
+async function ref(a, b = 39,) {
+  assert.sameValue(a, 42);
+  assert.sameValue(b, 39);
+  callCount = callCount + 1;
+}
+
+ref(42, undefined, 1).then(() => {
+    assert.sameValue(callCount, 1, 'function invoked exactly once');
+}).then($DONE, $DONE);
+
+assert.sameValue(ref.length, 1, 'length is properly set');