Skip line offset on out of range line numbers

idea/src/org/jetbrains/kotlin/idea/codeInsight/CodeInsightUtils.java

@@ -231,6 +231,10 @@ public class CodeInsightUtils {
         Document document = PsiDocumentManager.getInstance(file.getProject()).getDocument(file);
         if (document == null) return null;
 
+        if (line >= document.getLineCount()) {
+            return null;
+        }
+
         int lineStartOffset = document.getLineStartOffset(line);
         return CharArrayUtil.shiftForward(document.getCharsSequence(), lineStartOffset, " \t");
     }
@@ -240,6 +244,10 @@ public class CodeInsightUtils {
         Document document = PsiDocumentManager.getInstance(file.getProject()).getDocument(file);
         if (document == null) return null;
 
+        if (line >= document.getLineCount()) {
+            return null;
+        }
+
         int lineStartOffset = document.getLineEndOffset(line);
         return CharArrayUtil.shiftBackward(document.getCharsSequence(), lineStartOffset, " \t");
     }