Do not use implicitly nullable parameters and prepare release

ChangeLog.md

@@ -2,6 +2,12 @@
 
 All notable changes are documented in this file using the [Keep a CHANGELOG](http://keepachangelog.com/) principles.
 
+## [4.0.6] - 2024-03-02
+
+### Changed
+
+* Do not use implicitly nullable parameters
+
 ## [4.0.5] - 2023-05-07
 
 ### Changed
@@ -83,6 +89,7 @@ All notable changes are documented in this file using the [Keep a CHANGELOG](htt
 
 * This component is no longer supported on PHP 5.6
 
+[4.0.6]: https://github.com/sebastianbergmann/diff/compare/4.0.5...4.0.6
 [4.0.5]: https://github.com/sebastianbergmann/diff/compare/4.0.4...4.0.5
 [4.0.4]: https://github.com/sebastianbergmann/diff/compare/4.0.3...4.0.4
 [4.0.3]: https://github.com/sebastianbergmann/diff/compare/4.0.2...4.0.3

src/Differ.php

@@ -82,7 +82,7 @@ public function __construct($outputBuilder = null)
      * @param array|string $from
      * @param array|string $to
      */
-    public function diff($from, $to, LongestCommonSubsequenceCalculator $lcs = null): string
+    public function diff($from, $to, ?LongestCommonSubsequenceCalculator $lcs = null): string
     {
         $diff = $this->diffToArray(
             $this->normalizeDiffInput($from),
@@ -108,7 +108,7 @@ public function diff($from, $to, LongestCommonSubsequenceCalculator $lcs = null)
      * @param array|string                       $to
      * @param LongestCommonSubsequenceCalculator $lcs
      */
-    public function diffToArray($from, $to, LongestCommonSubsequenceCalculator $lcs = null): array
+    public function diffToArray($from, $to, ?LongestCommonSubsequenceCalculator $lcs = null): array
     {
         if (is_string($from)) {
             $from = $this->splitStringByLines($from);

src/Exception/ConfigurationException.php

@@ -22,7 +22,7 @@ public function __construct(
         string $expected,
         $value,
         int $code = 0,
-        Exception $previous = null
+        ?Exception $previous = null
     ) {
         parent::__construct(
             sprintf(