diff --git a/src/Application/FileProcessor.php b/src/Application/FileProcessor.php
index 6459f608864..92b5d3b10ac 100644
--- a/src/Application/FileProcessor.php
+++ b/src/Application/FileProcessor.php
@@ -45,7 +45,7 @@ final class FileProcessor
     }
 
     /**
-     * @return mixed
+     * @return int|bool
      */
     public function processFile(SplFileInfo $fileInfo)
     {
diff --git a/src/Printer/FormatPerservingPrinter.php b/src/Printer/FormatPerservingPrinter.php
index 63bc0e9400e..75f3bc26653 100644
--- a/src/Printer/FormatPerservingPrinter.php
+++ b/src/Printer/FormatPerservingPrinter.php
@@ -22,7 +22,7 @@ final class FormatPerservingPrinter
      * @param Node[] $newStmts
      * @param Node[] $oldStmts
      * @param Node[] $oldTokens
-     * @return mixed
+     * @return int|bool
      */
     public function printToFile(SplFileInfo $fileInfo, array $newStmts, array $oldStmts, array $oldTokens)
     {