diff --git a/compiler/frontend.common-psi/src/org/jetbrains/kotlin/diagnostics/LightTreePositioningStrategy.kt b/compiler/frontend.common-psi/src/org/jetbrains/kotlin/diagnostics/LightTreePositioningStrategy.kt
index abdc4c1f21f..d1372eec03d 100644
--- a/compiler/frontend.common-psi/src/org/jetbrains/kotlin/diagnostics/LightTreePositioningStrategy.kt
+++ b/compiler/frontend.common-psi/src/org/jetbrains/kotlin/diagnostics/LightTreePositioningStrategy.kt
@@ -82,10 +82,10 @@ private val FILLER_TOKENS = setOf(
 )
 
 private fun LighterASTNode.nonFillerFirstChildOrSelf(tree: FlyweightCapableTreeStructure<LighterASTNode>): LighterASTNode =
-    getChildren(tree).firstOrNull { !(it?.isFiller() ?: false) } ?: this
+    getChildren(tree).firstOrNull { !it.isFiller() } ?: this
 
 internal fun LighterASTNode.nonFillerLastChildOrSelf(tree: FlyweightCapableTreeStructure<LighterASTNode>): LighterASTNode =
-    getChildren(tree).lastOrNull { !(it?.isFiller() ?: false) } ?: this
+    getChildren(tree).lastOrNull { !it.isFiller() } ?: this
 
 internal fun LighterASTNode.isFiller() = tokenType in FILLER_TOKENS
 
diff --git a/compiler/frontend.common-psi/src/org/jetbrains/kotlin/diagnostics/UnreachableCodeLightTreeHelper.kt b/compiler/frontend.common-psi/src/org/jetbrains/kotlin/diagnostics/UnreachableCodeLightTreeHelper.kt
index 946897926a6..14489a589a0 100644
--- a/compiler/frontend.common-psi/src/org/jetbrains/kotlin/diagnostics/UnreachableCodeLightTreeHelper.kt
+++ b/compiler/frontend.common-psi/src/org/jetbrains/kotlin/diagnostics/UnreachableCodeLightTreeHelper.kt
@@ -85,7 +85,7 @@ class UnreachableCodeLightTreeHelper(val tree: FlyweightCapableTreeStructure<Nod
     }
 }
 
-internal fun LighterASTNode.getChildren(tree: FlyweightCapableTreeStructure<LighterASTNode>): List<LighterASTNode?> {
+internal fun LighterASTNode.getChildren(tree: FlyweightCapableTreeStructure<LighterASTNode>): List<LighterASTNode> {
     val children = Ref<Array<LighterASTNode?>>()
     val count = tree.getChildren(this, children)
     return if (count > 0) children.get().filterNotNull() else emptyList()