diff --git a/compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/smartcasts/DelegatingDataFlowInfo.kt b/compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/smartcasts/DelegatingDataFlowInfo.kt
index 0344a33fad2..fadc1e42efb 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/smartcasts/DelegatingDataFlowInfo.kt
+++ b/compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/smartcasts/DelegatingDataFlowInfo.kt
@@ -18,13 +18,15 @@ package org.jetbrains.kotlin.resolve.calls.smartcasts
 
 import com.google.common.collect.*
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
-import org.jetbrains.kotlin.resolve.calls.smartcasts.Nullability.NOT_NULL
+import org.jetbrains.kotlin.types.*
 import org.jetbrains.kotlin.types.KotlinType
 import org.jetbrains.kotlin.types.TypeUtils
-import org.jetbrains.kotlin.types.isFlexible
-import org.jetbrains.kotlin.types.typeUtil.isSubtypeOf
+import org.jetbrains.kotlin.types.typeUtil.*
+
 import java.util.*
 
+import org.jetbrains.kotlin.resolve.calls.smartcasts.Nullability.NOT_NULL
+
 internal class DelegatingDataFlowInfo private constructor(
         private val parent: DataFlowInfo?,
         private val nullabilityInfo: ImmutableMap<DataFlowValue, Nullability>,
@@ -102,13 +104,10 @@ internal class DelegatingDataFlowInfo private constructor(
         }
 
         val enrichedTypes = Sets.newHashSetWithExpectedSize<KotlinType>(types.size + 1)
-
         val originalType = key.type
-        val notNullable = TypeUtils.makeNotNullable(originalType)
-        if (notNullable != originalType) {
-            enrichedTypes.add(notNullable)
+        if (originalType.isMarkedNullable) {
+            enrichedTypes.add(TypeUtils.makeNotNullable(originalType))
         }
-
         for (type in types) {
             enrichedTypes.add(TypeUtils.makeNotNullable(type))
         }