1 files changed, 25 insertions, 0 deletions
diff --git a/js/src/tests/test262/language/statements/class/elements/fields-duplicate-privatenames.js b/js/src/tests/test262/language/statements/class/elements/fields-duplicate-privatenames.js
new file mode 100644
index 0000000000..da13cf7b43
--- /dev/null
+++ b/js/src/tests/test262/language/statements/class/elements/fields-duplicate-privatenames.js
@@ -0,0 +1,25 @@
+// |reftest| error:SyntaxError
+// Copyright 2017 Valerie Young.  All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+description: Syntax error if the same private field defined twice
+esid: sec-class-definitions-static-semantics-early-errors
+features: [class, class-fields-private]
+negative:
+  phase: parse
+  type: SyntaxError
+info: |
+  Static Semantics: Early Errors
+
+    ClassBody : ClassElementList
+    It is a Syntax Error if PrivateBoundNames of ClassBody contains any duplicate entries.
+---*/
+
+
+$DONOTEVALUATE();
+
+class C {
+  #x;
+  #x;
+}