diff --git a/src/Illuminate/Container/ContextualBindingBuilder.php b/src/Illuminate/Container/ContextualBindingBuilder.php
index 1d15dcd3da6a..ae4c02a61f1a 100644
--- a/src/Illuminate/Container/ContextualBindingBuilder.php
+++ b/src/Illuminate/Container/ContextualBindingBuilder.php
@@ -86,7 +86,7 @@ public function giveTagged($tag)
      * Specify the configuration item to bind as a primitive.
      *
      * @param  string  $key
-     * @param  ?string  $default
+     * @param  mixed  $default
      * @return void
      */
     public function giveConfig($key, $default = null)
diff --git a/src/Illuminate/Contracts/Container/ContextualBindingBuilder.php b/src/Illuminate/Contracts/Container/ContextualBindingBuilder.php
index 1fc7fc15932f..1d84ef8c709d 100644
--- a/src/Illuminate/Contracts/Container/ContextualBindingBuilder.php
+++ b/src/Illuminate/Contracts/Container/ContextualBindingBuilder.php
@@ -32,7 +32,7 @@ public function giveTagged($tag);
      * Specify the configuration item to bind as a primitive.
      *
      * @param  string  $key
-     * @param  ?string  $default
+     * @param  mixed  $default
      * @return void
      */
     public function giveConfig($key, $default = null);