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diff --git a/js/src/tests/test262/language/statements/class/definition/early-errors-class-method-duplicate-parameters.js b/js/src/tests/test262/language/statements/class/definition/early-errors-class-method-duplicate-parameters.js
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+// |reftest| error:SyntaxError
+// Copyright 2019 Mike Pennisi. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-method-definitions
+description: Formal parameters may not contain duplicates
+info: |
+  # 14.3 Method Definitions
+
+  MethodDefinition[Yield, Await]:
+    PropertyName[?Yield, ?Await](UniqueFormalParameters[~Yield, ~Await]){FunctionBody[~Yield, ~Await]}
+
+  # 14.1.2 Static Semantics: Early Errors
+
+  UniqueFormalParameters:FormalParameters
+
+  - It is a Syntax Error if BoundNames of FormalParameters contains any
+    duplicate elements.
+negative:
+  phase: parse
+  type: SyntaxError
+---*/
+
+$DONOTEVALUATE();
+
+class Foo {
+  foo(a, a) { }
+}