diff --git a/libraries/stdlib/src/kotlin/io/Files.kt b/libraries/stdlib/src/kotlin/io/Files.kt
index 960c9093b59..54d654c29f5 100644
--- a/libraries/stdlib/src/kotlin/io/Files.kt
+++ b/libraries/stdlib/src/kotlin/io/Files.kt
@@ -86,7 +86,7 @@ public inline fun File.reader(): FileReader = FileReader(this)
 /**
  * Iterates through each line of this file then closing the underlying [[Reader]] when its completed
  */
-public inline fun File.forEachLine(block: (String) -> Unit): Unit = reader().forEachLine(block)
+public inline fun File.forEachLine(block: (String) -> Any): Unit = reader().forEachLine(block)
 
 /**
  * Reads the entire content of the file as bytes
diff --git a/libraries/stdlib/src/kotlin/io/JIO.kt b/libraries/stdlib/src/kotlin/io/JIO.kt
index 841f65d6ff7..a980a337cc6 100644
--- a/libraries/stdlib/src/kotlin/io/JIO.kt
+++ b/libraries/stdlib/src/kotlin/io/JIO.kt
@@ -212,7 +212,7 @@ public inline fun Writer.buffered(bufferSize: Int = defaultBufferSize): Buffered
 /**
  * Iterates through each line of this reader then closing the [[Reader]] when its completed
  */
-public inline fun Reader.forEachLine(block: (String) -> Unit): Unit {
+public inline fun Reader.forEachLine(block: (String) -> Any): Unit {
     this.use{
         val iter = buffered().lineIterator()
         while (iter.hasNext) {