added missing typehints

src/Utils/Arrays.php

@@ -138,8 +138,8 @@ public static function flatten(array $arr, bool $preserveKeys = false): array
 	{
 		$res = [];
 		$cb = $preserveKeys
-			? function ($v, $k) use (&$res) { $res[$k] = $v; }
-		: function ($v) use (&$res) { $res[] = $v; };
+			? function ($v, $k) use (&$res): void { $res[$k] = $v; }
+		: function ($v) use (&$res): void { $res[] = $v; };
 		array_walk_recursive($arr, $cb);
 		return $res;
 	}

src/Utils/Callback.php

@@ -66,15 +66,15 @@ public static function invokeArgs($callable, array $args = [])
 	 */
 	public static function invokeSafe(string $function, array $args, callable $onError)
 	{
-		$prev = set_error_handler(function ($severity, $message, $file) use ($onError, &$prev, $function) {
+		$prev = set_error_handler(function ($severity, $message, $file) use ($onError, &$prev, $function): ?bool {
 			if ($file === __FILE__) {
 				$msg = $message;
 				if (ini_get('html_errors')) {
 					$msg = html_entity_decode(strip_tags($msg));
 				}
 				$msg = preg_replace("#^$function\(.*?\): #", '', $msg);
 				if ($onError($msg, $severity) !== false) {
-					return;
+					return null;
 				}
 			}
 			return $prev ? $prev(...func_get_args()) : false;

src/Utils/Image.php

@@ -152,7 +152,7 @@ public static function fromFile(string $file, int &$detectedFormat = null)
 			$detectedFormat = null;
 			throw new UnknownImageFileException(is_file($file) ? "Unknown type of file '$file'." : "File '$file' not found.");
 		}
-		return new static(Callback::invokeSafe('imagecreatefrom' . image_type_to_extension($detectedFormat, false), [$file], function (string $message) {
+		return new static(Callback::invokeSafe('imagecreatefrom' . image_type_to_extension($detectedFormat, false), [$file], function (string $message): void {
 			throw new ImageException($message);
 		}));
 	}
@@ -174,7 +174,7 @@ public static function fromString(string $s, int &$detectedFormat = null)
 			$detectedFormat = isset(self::$formats[$tmp]) ? $tmp : null;
 		}
 
-		return new static(Callback::invokeSafe('imagecreatefromstring', [$s], function (string $message) {
+		return new static(Callback::invokeSafe('imagecreatefromstring', [$s], function (string $message): void {
 			throw new ImageException($message);
 		}));
 	}

src/Utils/Random.php

@@ -24,7 +24,7 @@ final class Random
 	 */
 	public static function generate(int $length = 10, string $charlist = '0-9a-z'): string
 	{
-		$charlist = count_chars(preg_replace_callback('#.-.#', function (array $m) {
+		$charlist = count_chars(preg_replace_callback('#.-.#', function (array $m): string {
 			return implode('', range($m[0][0], $m[0][2]));
 		}, $charlist), 3);
 		$chLen = strlen($charlist);

src/Utils/Strings.php

@@ -492,7 +492,7 @@ public static function replace(string $subject, $pattern, $replacement = null, i
 	/** @internal */
 	public static function pcre(string $func, array $args)
 	{
-		$res = Callback::invokeSafe($func, $args, function (string $message) use ($args) {
+		$res = Callback::invokeSafe($func, $args, function (string $message) use ($args): void {
 			// compile-time error, not detectable by preg_last_error
 			throw new RegexpException($message . ' in pattern: ' . implode(' or ', (array) $args[0]));
 		});

tests/bootstrap.php

@@ -22,7 +22,7 @@
 @mkdir(TEMP_DIR);
 
 
-function test(\Closure $function)
+function test(\Closure $function): void
 {
 	$function();
 }