1 files changed, 65 insertions, 0 deletions
diff --git a/js/src/tests/test262/language/statements/class/async-gen-method/params-trailing-comma-single.js b/js/src/tests/test262/language/statements/class/async-gen-method/params-trailing-comma-single.js
new file mode 100644
index 0000000000..a84e93b285
--- /dev/null
+++ b/js/src/tests/test262/language/statements/class/async-gen-method/params-trailing-comma-single.js
@@ -0,0 +1,65 @@
+// |reftest| async
+// This file was procedurally generated from the following sources:
+// - src/function-forms/params-trailing-comma-single.case
+// - src/function-forms/default/cls-decl-async-gen-meth.template
+/*---
+description: A trailing comma should not increase the respective length, using a single parameter (class declaration async generator method)
+esid: sec-class-definitions-runtime-semantics-evaluation
+features: [async-iteration]
+flags: [generated, async]
+info: |
+    ClassDeclaration : class BindingIdentifier ClassTail
+
+    1. Let className be StringValue of BindingIdentifier.
+    2. Let value be the result of ClassDefinitionEvaluation of ClassTail with
+       argument className.
+    [...]
+
+    14.5.14 Runtime Semantics: ClassDefinitionEvaluation
+
+    21. For each ClassElement m in order from methods
+        a. If IsStatic of m is false, then
+           i. Let status be the result of performing
+              PropertyDefinitionEvaluation for m with arguments proto and
+              false.
+        [...]
+
+    Runtime Semantics: PropertyDefinitionEvaluation
+
+    AsyncGeneratorMethod :
+        async [no LineTerminator here] * PropertyName ( UniqueFormalParameters )
+            { AsyncGeneratorBody }
+
+    1. Let propKey be the result of evaluating PropertyName.
+    2. ReturnIfAbrupt(propKey).
+    3. If the function code for this AsyncGeneratorMethod is strict mode code, let strict be true.
+       Otherwise let strict be false.
+    4. Let scope be the running execution context's LexicalEnvironment.
+    5. Let closure be ! AsyncGeneratorFunctionCreate(Method, UniqueFormalParameters,
+       AsyncGeneratorBody, scope, strict).
+    [...]
+
+
+    Trailing comma in the parameters list
+
+    14.1 Function Definitions
+
+    FormalParameters[Yield, Await] : FormalParameterList[?Yield, ?Await] ,
+---*/
+
+var callCount = 0;
+class C {
+  async *method(a,) {
+    assert.sameValue(a, 42);
+    callCount = callCount + 1;
+  }
+}
+
+// Stores a reference `ref` for case evaluation
+var ref = C.prototype.method;
+
+ref(42, 39).next().then(() => {
+    assert.sameValue(callCount, 1, 'method invoked exactly once');
+}).then($DONE, $DONE);
+
+assert.sameValue(ref.length, 1, 'length is properly set');