1 files changed, 81 insertions, 0 deletions
diff --git a/js/src/tests/test262/language/arguments-object/cls-expr-async-gen-meth-args-trailing-comma-spread-operator.js b/js/src/tests/test262/language/arguments-object/cls-expr-async-gen-meth-args-trailing-comma-spread-operator.js
new file mode 100644
index 0000000000..86fbb5e4f5
--- /dev/null
+++ b/js/src/tests/test262/language/arguments-object/cls-expr-async-gen-meth-args-trailing-comma-spread-operator.js
@@ -0,0 +1,81 @@
+// |reftest| async
+// This file was procedurally generated from the following sources:
+// - src/arguments/args-trailing-comma-spread-operator.case
+// - src/arguments/default/cls-expr-async-gen-meth.template
+/*---
+description: A trailing comma should not increase the arguments.length, using spread args (class expression async generator method)
+esid: sec-class-definitions-runtime-semantics-evaluation
+features: [async-iteration]
+flags: [generated, async]
+info: |
+    ClassExpression : class BindingIdentifieropt ClassTail
+
+    1. If BindingIdentifieropt is not present, let className be undefined.
+    2. Else, let className be StringValue of BindingIdentifier.
+    3. 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 arguments list
+
+    Left-Hand-Side Expressions
+
+    Arguments :
+        ( )
+        ( ArgumentList )
+        ( ArgumentList , )
+
+    ArgumentList :
+        AssignmentExpression
+        ... AssignmentExpression
+        ArgumentList , AssignmentExpression
+        ArgumentList , ... AssignmentExpression
+---*/
+var arr = [2, 3];
+
+
+
+var callCount = 0;
+var C = class {
+  async *method() {
+    assert.sameValue(arguments.length, 4);
+    assert.sameValue(arguments[0], 42);
+    assert.sameValue(arguments[1], 1);
+    assert.sameValue(arguments[2], 2);
+    assert.sameValue(arguments[3], 3);
+    callCount = callCount + 1;
+  }
+};
+
+// Stores a reference `ref` for case evaluation
+var ref = C.prototype.method;
+
+ref(42, ...[1], ...arr,).next().then(() => {
+    assert.sameValue(callCount, 1, 'method invoked exactly once');
+}).then($DONE, $DONE);
+