--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/src/share/classes/com/sun/tools/javac/comp/TypeEnvs.java	Tue Jun 17 11:11:59 2014 -0400
@@ -0,0 +1,63 @@
+/*
+ * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package com.sun.tools.javac.comp;
+
+import java.util.Collection;
+import java.util.HashMap;
+import com.sun.tools.javac.code.Symbol.TypeSymbol;
+import com.sun.tools.javac.util.Context;
+
+/** This class contains the type environments used by Enter, MemberEnter,
+ *  Attr, DeferredAttr, and Lower.
+ *
+ *  <p><b>This is NOT part of any supported API.
+ *  If you write code that depends on this, you do so at your own risk.
+ *  This code and its internal interfaces are subject to change or
+ *  deletion without notice.</b>
+ */
+class TypeEnvs {
+    private static final long serialVersionUID = 571524752489954631L;
+
+    protected static final Context.Key<TypeEnvs> typeEnvsKey = new Context.Key<>();
+    public static TypeEnvs instance(Context context) {
+        TypeEnvs instance = context.get(typeEnvsKey);
+        if (instance == null)
+            instance = new TypeEnvs(context);
+        return instance;
+    }
+
+    private HashMap<TypeSymbol,Env<AttrContext>> map;
+    protected TypeEnvs(Context context) {
+        map = new HashMap<>();
+        context.put(typeEnvsKey, this);
+    }
+
+    Env<AttrContext> get(TypeSymbol sym) { return map.get(sym); }
+    Env<AttrContext> put(TypeSymbol sym, Env<AttrContext> env) { return map.put(sym, env); }
+    Env<AttrContext> remove(TypeSymbol sym) { return map.remove(sym); }
+    Collection<Env<AttrContext>> values() { return map.values(); }
+    void clear() { map.clear(); }
+}