diff --git a/libraries/stdlib/js/src/kotlin/collections/ArraySorting.kt b/libraries/stdlib/js/src/kotlin/collections/ArraySorting.kt
index 992805d6bde..9bb1c2a99db 100644
--- a/libraries/stdlib/js/src/kotlin/collections/ArraySorting.kt
+++ b/libraries/stdlib/js/src/kotlin/collections/ArraySorting.kt
@@ -96,6 +96,7 @@ private fun <T> mergeSort(array: Array<T>, buffer: Array<T>, start: Int, end: In
             else /* rightIndex <= end */ -> {
                 target[i] = right[rightIndex]
                 rightIndex++
+                Unit  // TODO: Fix KT-31506
             }
         }
     }