DelegatingDataFlowInfo: default constructor

compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/smartcasts/DataFlowInfo.kt

@@ -98,7 +98,5 @@ interface DataFlowInfo {
 
 object DataFlowInfoFactory {
     @JvmField
-    val EMPTY: DataFlowInfo = DelegatingDataFlowInfo(
+    val EMPTY: DataFlowInfo = DelegatingDataFlowInfo()
-            null, ImmutableMap.of<DataFlowValue, Nullability>(), DelegatingDataFlowInfo.newTypeInfo()
-    )
 }

compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/smartcasts/DelegatingDataFlowInfo.kt

@@ -27,11 +27,11 @@ import java.util.*
 
 import org.jetbrains.kotlin.resolve.calls.smartcasts.Nullability.NOT_NULL
 
-internal class DelegatingDataFlowInfo(
+internal class DelegatingDataFlowInfo private constructor(
-        private val parent: DataFlowInfo?,
+        private val parent: DataFlowInfo? = null,
-        private val nullabilityInfo: ImmutableMap<DataFlowValue, Nullability>,
+        private val nullabilityInfo: ImmutableMap<DataFlowValue, Nullability> = ImmutableMap.of(),
         // Also immutable
-        private val typeInfo: SetMultimap<DataFlowValue, KotlinType>,
+        private val typeInfo: SetMultimap<DataFlowValue, KotlinType> = newTypeInfo(),
         /**
          * Value for which type info was cleared or reassigned at this point
          * so parent type info should not be in use
@@ -39,6 +39,8 @@ internal class DelegatingDataFlowInfo(
         private val valueWithGivenTypeInfo: DataFlowValue? = null
 ) : DataFlowInfo {
 
+    constructor(): this(null)
+
     override val completeNullabilityInfo: Map<DataFlowValue, Nullability>
         get() {
             val result = Maps.newHashMap<DataFlowValue, Nullability>()