diff --git a/jps/jps-plugin/src/org/jetbrains/kotlin/jps/incremental/IncrementalCacheImpl.kt b/jps/jps-plugin/src/org/jetbrains/kotlin/jps/incremental/IncrementalCacheImpl.kt
index 7e33f356920..76166540794 100644
--- a/jps/jps-plugin/src/org/jetbrains/kotlin/jps/incremental/IncrementalCacheImpl.kt
+++ b/jps/jps-plugin/src/org/jetbrains/kotlin/jps/incremental/IncrementalCacheImpl.kt
@@ -263,7 +263,7 @@ public class IncrementalCacheImpl(
 
         val changes =
                 if (IncrementalCompilation.isExperimental())
-                    dirtyClasses.map { createChangeInfo(it) }.asSequence().filterNotNull()
+                    dirtyClasses.mapNotNull { createChangeInfo(it) }.asSequence()
                 else
                     emptySequence<ChangeInfo>()
 
diff --git a/jps/jps-plugin/src/org/jetbrains/kotlin/jps/incremental/LookupStorage.kt b/jps/jps-plugin/src/org/jetbrains/kotlin/jps/incremental/LookupStorage.kt
index 32903e254f2..0345dbb290c 100644
--- a/jps/jps-plugin/src/org/jetbrains/kotlin/jps/incremental/LookupStorage.kt
+++ b/jps/jps-plugin/src/org/jetbrains/kotlin/jps/incremental/LookupStorage.kt
@@ -59,10 +59,10 @@ class LookupStorage(private val targetDataDir: File) : BasicMapsOwner() {
         val key = LookupSymbolKey(lookupSymbol.name, lookupSymbol.scope)
         val fileIds = lookupMap[key] ?: return emptySet()
 
-        return fileIds.map {
+        return fileIds.mapNotNull {
             // null means it's outdated
             idToFile[it]?.path
-        }.filterNotNull()
+        }
     }
 
     public fun add(lookupSymbol: LookupSymbol, containingPaths: Collection<String>) {
@@ -138,7 +138,7 @@ class LookupStorage(private val targetDataDir: File) : BasicMapsOwner() {
         }
 
         for (lookup in lookupMap.keys) {
-            val fileIds = lookupMap[lookup]!!.map { oldIdToNewId[it] }.filterNotNull().toSet()
+            val fileIds = lookupMap[lookup]!!.mapNotNull { oldIdToNewId[it] }.toSet()
 
             if (fileIds.isEmpty()) {
                 lookupMap.remove(lookup)