1 files changed, 53 insertions, 0 deletions
diff --git a/js/src/tests/test262/language/expressions/async-arrow-function/dflt-params-trailing-comma.js b/js/src/tests/test262/language/expressions/async-arrow-function/dflt-params-trailing-comma.js
new file mode 100644
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+++ b/js/src/tests/test262/language/expressions/async-arrow-function/dflt-params-trailing-comma.js
@@ -0,0 +1,53 @@
+// |reftest| async
+// This file was procedurally generated from the following sources:
+// - src/function-forms/dflt-params-trailing-comma.case
+// - src/function-forms/default/async-arrow-function.template
+/*---
+description: A trailing comma should not increase the respective length, using default parameters (async arrow function expression)
+esid: sec-async-arrow-function-definitions
+features: [async-functions]
+flags: [generated, async]
+info: |
+    14.7 Async Arrow Function Definitions
+
+    AsyncArrowFunction :
+      ...
+      CoverCallExpressionAndAsyncArrowHead => AsyncConciseBody
+
+    AsyncConciseBody :
+      { AsyncFunctionBody }
+
+    ...
+
+    Supplemental Syntax
+
+    When processing an instance of the production AsyncArrowFunction :
+    CoverCallExpressionAndAsyncArrowHead => AsyncConciseBody the interpretation of
+    CoverCallExpressionAndAsyncArrowHead is refined using the following grammar:
+
+    AsyncArrowHead :
+      async ArrowFormalParameters
+
+
+    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
+var ref = async (a, b = 39,) => {
+  assert.sameValue(a, 42);
+  assert.sameValue(b, 39);
+  callCount = callCount + 1;
+};
+
+ref(42, undefined, 1).then(() => {
+  assert.sameValue(callCount, 1, 'async arrow function invoked exactly once')
+}).then($DONE, $DONE);
+
+assert.sameValue(ref.length, 1, 'length is properly set');