1 files changed, 32 insertions, 0 deletions
diff --git a/js/src/frontend/ScopeIndex.h b/js/src/frontend/ScopeIndex.h
new file mode 100644
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+++ b/js/src/frontend/ScopeIndex.h
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef frontend_ScopeIndex_h
+#define frontend_ScopeIndex_h
+
+#include <cstdint>  // uint32_t, UINT32_MAX
+
+#include "frontend/TypedIndex.h"  // TypedIndex
+
+namespace js {
+
+class Scope;
+
+class ScopeIndex : public frontend::TypedIndex<Scope> {
+  // Delegate constructors;
+  using Base = frontend::TypedIndex<Scope>;
+  using Base::Base;
+
+  static constexpr uint32_t InvalidIndex = UINT32_MAX;
+
+ public:
+  static constexpr ScopeIndex invalid() { return ScopeIndex(InvalidIndex); }
+  bool isValid() const { return index != InvalidIndex; }
+};
+
+} /* namespace js */
+
+#endif /* frontend_ScopeIndex_h */