From 7e9deb76022095805790bbb814fed3e942478370 Mon Sep 17 00:00:00 2001
From: Dmitriy Novozhilov <dmitriy.novozhilov@jetbrains.com>
Date: Tue, 15 Dec 2020 12:58:34 +0300
Subject: [PATCH] [FIR] Fix NPE in light tree source utils

---
 .../analysis/diagnostics/LightTreePositioningStrategy.kt    | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/LightTreePositioningStrategy.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/LightTreePositioningStrategy.kt
index 1f496c79d03..5c0db8b0dea 100644
--- a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/LightTreePositioningStrategy.kt
+++ b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/LightTreePositioningStrategy.kt
@@ -45,10 +45,10 @@ private val DOC_AND_COMMENT_TOKENS = setOf(
 private fun hasSyntaxErrors(node: LighterASTNode, tree: FlyweightCapableTreeStructure<LighterASTNode>): Boolean {
     if (node.tokenType == TokenType.ERROR_ELEMENT) return true
 
-    val childrenRef = Ref<Array<LighterASTNode>>()
+    val childrenRef = Ref<Array<LighterASTNode?>?>()
     tree.getChildren(node, childrenRef)
-    val children = childrenRef.get()
-    return children.lastOrNull {
+    val children = childrenRef.get() ?: return false
+    return children.filterNotNull().lastOrNull {
         val tokenType = it.tokenType
         tokenType !is KtSingleValueToken && tokenType !in DOC_AND_COMMENT_TOKENS
     }?.let { hasSyntaxErrors(it, tree) } == true