Hopefully fixed KT-4339 Auto-import suggestion doesn't go away for a long time

#KT-4339 Fixed

compiler/util/src/org/jetbrains/jet/utils/CachedValueProperty.kt

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2010-2014 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.jet.utils
+
+import kotlin.properties.ReadOnlyProperty
+
+public class CachedValueProperty<TValue : Any, TTimestamp : Any>(private val calculator: () -> TValue,
+                                                         private val timestampCalculator: () -> TTimestamp) : ReadOnlyProperty<Any?, TValue> {
+    private var value: TValue? = null
+    private var timestamp: TTimestamp? = null
+
+    public override fun get(thisRef: Any?, desc: PropertyMetadata): TValue {
+        val currentTimestamp = timestampCalculator()
+        if (value == null || timestamp != currentTimestamp) {
+            value = calculator()
+            timestamp = currentTimestamp
+        }
+        return value!!
+    }
+}