1 files changed, 69 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/fields/ergonomic-1.js b/js/src/jit-test/tests/fields/ergonomic-1.js
new file mode 100644
index 0000000000..7aa75ab30b
--- /dev/null
+++ b/js/src/jit-test/tests/fields/ergonomic-1.js
@@ -0,0 +1,69 @@
+class Base {
+  constructor(o) {
+    return o;
+  }
+}
+
+class A extends Base {
+  #x = 12;
+  #y = 13;
+  static has(o) {
+    return A.evalStr(o, '#x in o');
+  }
+
+  static evalStr(o, str) {
+    return eval(str);
+  }
+}
+
+var obj = {};
+assertEq(A.has(obj), false);
+new A(obj);
+assertEq(A.has(obj), true);
+
+A.evalStr(obj, `#x in o in o`)  // 'false' in o
+
+function assertSyntaxError(functionText) {
+  let threw = false;
+  let exception = undefined;
+  try {
+    A.evalStr({}, functionText)
+  } catch (e) {
+    exception = e;
+    threw = true;
+  }
+  assertEq(threw, true);
+  assertEq(exception instanceof SyntaxError, true);
+}
+
+assertSyntaxError(`#x`);
+assertSyntaxError(`#x == undefined`);
+assertSyntaxError(`1 + #x in o`)
+assertSyntaxError(`#z in o`);
+
+assertSyntaxError(`for (#x in o) { return 1;}`)
+assertSyntaxError(`!#x in o`)
+assertSyntaxError(`+#x in o`)
+assertSyntaxError(`-#x in o`)
+assertSyntaxError(`~#x in o`)
+assertSyntaxError(`void #x in o`)
+assertSyntaxError(`typeof #x in o`)
+assertSyntaxError(`++#x in o`)
+assertSyntaxError(`--#x in o`)
+
+assertSyntaxError(`#x in #y in o`)
+assertSyntaxError(`{} instanceof #x in o`)
+assertSyntaxError(`10 > #x in o`)
+var threw = true
+try {
+  eval(`class Async {
+    #x;
+    async func(o) {
+      await #x in o;
+    }
+  }`);
+  threw = false;
+} catch (e) {
+  assertEq(e instanceof SyntaxError, true);
+}
+assertEq(threw, true);