1 files changed, 48 insertions, 0 deletions
diff --git a/js/src/tests/test262/language/arguments-object/cls-decl-async-gen-func-args-trailing-comma-undefined.js b/js/src/tests/test262/language/arguments-object/cls-decl-async-gen-func-args-trailing-comma-undefined.js
new file mode 100644
index 0000000000..a2b5b4cc25
--- /dev/null
+++ b/js/src/tests/test262/language/arguments-object/cls-decl-async-gen-func-args-trailing-comma-undefined.js
@@ -0,0 +1,48 @@
+// |reftest| async
+// This file was procedurally generated from the following sources:
+// - src/arguments/args-trailing-comma-undefined.case
+// - src/arguments/default/async-gen-func-decl.template
+/*---
+description: A trailing comma after undefined should not increase the arguments.length (async generator function declaration)
+esid: sec-asyncgenerator-definitions-instantiatefunctionobject
+features: [async-iteration]
+flags: [generated, async]
+info: |
+    AsyncGeneratorDeclaration : async [no LineTerminator here] function * BindingIdentifier
+        ( FormalParameters ) { AsyncGeneratorBody }
+
+        [...]
+        3. Let F be ! AsyncGeneratorFunctionCreate(Normal, FormalParameters, AsyncGeneratorBody,
+            scope, strict).
+        [...]
+
+
+    Trailing comma in the arguments list
+
+    Left-Hand-Side Expressions
+
+    Arguments :
+        ( )
+        ( ArgumentList )
+        ( ArgumentList , )
+
+    ArgumentList :
+        AssignmentExpression
+        ... AssignmentExpression
+        ArgumentList , AssignmentExpression
+        ArgumentList , ... AssignmentExpression
+---*/
+
+
+var callCount = 0;
+// Stores a reference `ref` for case evaluation
+async function* ref() {
+  assert.sameValue(arguments.length, 2);
+  assert.sameValue(arguments[0], 42);
+  assert.sameValue(arguments[1], undefined);
+  callCount = callCount + 1;
+}
+
+ref(42, undefined,).next().then(() => {
+    assert.sameValue(callCount, 1, 'generator function invoked exactly once');
+}).then($DONE, $DONE);