Private fields

test/mjsunit/harmony/class-privates-errors.js

+// Copyright 2016 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --harmony-private-class-fields
+
+// Adding the same property twice
+// TODO(bakkot) instantiating 'Base' should be an error
+{
+  class Base {
+    constructor() { return new Derived; }
+  }
+
+  class Derived extends Base {
+    #a = 0;
+  }
+}
+
+// Deleting a private field
+// TODO(bakkot) each of these lines should be a syntax error
+{
+  class C { #a; m(){ delete #a; } }
+  class D { #a; m(){ delete this.#a; } }
+}
+
+// Referencing a private field outside a class
+// TODO(bakkot) this is not spec'd to be a syntax error, but should be
+{
+  () => #a;
+  () => this.#a;
+}
+
+// Referencing a private field inside a class which doesn't declare it
+// TODO(bakkot) it is unclear whether or not this will be an error, see
+// https://github.com/tc39/proposal-private-fields/issues/49
+{
+  class C {
+    #a;
+    m(){ #b; }
+  }
+}
+
+// Referencing a private field through 'eval'
+// TODO(bakkot) it is unclear whether or not this will be an error, see
+// https://github.com/tc39/proposal-private-fields/issues/47
+{
+  class C {
+    #a = 0;
+    m() { return eval('#a'); }
+  }
+  let c = new C;
+  assertEquals(0, c.m());
+}