Example of altering the Symfony PHP8.0 polyfill to be parsable under PHP 5.6

php56-php8-pollyfill.diff

diff --git a/src/Php80/Php80.php b/src/Php80/Php80.php
index ba74359..bc2533c 100644
--- a/src/Php80/Php80.php
+++ b/src/Php80/Php80.php
@@ -20,12 +20,12 @@ namespace Symfony\Polyfill\Php80;
  */
 final class Php80
 {
-    public static function fdiv(float $dividend, float $divisor): float
+    public static function fdiv(float $dividend, float $divisor) //: float
     {
         return @($dividend / $divisor);
     }

-    public static function get_debug_type($value): string
+    public static function get_debug_type($value) //: string
     {
         switch (true) {
             case null === $value: return 'null';
@@ -57,7 +57,7 @@ final class Php80
         return (get_parent_class($class) ?: key(class_implements($class)) ?: 'class').'@anonymous';
     }

-    public static function preg_last_error_msg(): string
+    public static function preg_last_error_msg() //: string
     {
         switch (preg_last_error()) {
             case PREG_INTERNAL_ERROR:
@@ -79,17 +79,17 @@ final class Php80
         }
     }

-    public static function str_contains(string $haystack, string $needle): bool
+    public static function str_contains(string $haystack, string $needle) //: bool
     {
         return '' === $needle || false !== strpos($haystack, $needle);
     }

-    public static function str_starts_with(string $haystack, string $needle): bool
+    public static function str_starts_with(string $haystack, string $needle) //: bool
     {
         return 0 === \strncmp($haystack, $needle, \strlen($needle));
     }

-    public static function str_ends_with(string $haystack, string $needle): bool
+    public static function str_ends_with(string $haystack, string $needle) //: bool
     {
         return '' === $needle || $needle === \substr($haystack, -\strlen($needle));
     }
diff --git a/src/Php80/bootstrap.php b/src/Php80/bootstrap.php
index dc2aaa4..b8366a7 100644
--- a/src/Php80/bootstrap.php
+++ b/src/Php80/bootstrap.php
@@ -13,23 +13,23 @@ use Symfony\Polyfill\Php80 as p;

 if (PHP_VERSION_ID < 80000) {
     if (!function_exists('fdiv')) {
-        function fdiv(float $dividend, float $divisor): float { return p\Php80::fdiv($dividend, $divisor); }
+        function fdiv(float $dividend, float $divisor) /*: float */ { return p\Php80::fdiv($dividend, $divisor); }
     }

     if (!function_exists('preg_last_error_msg')) {
-        function preg_last_error_msg(): string { return p\Php80::preg_last_error_msg(); }
+        function preg_last_error_msg() /*: string */ { return p\Php80::preg_last_error_msg(); }
     }

     if (!function_exists('str_contains')) {
-        function str_contains(string $haystack, string $needle): bool { return p\Php80::str_contains($haystack, $needle); }
+        function str_contains(string $haystack, string $needle) /*: bool */ { return p\Php80::str_contains($haystack, $needle); }
     }

     if (!function_exists('str_starts_with')) {
-        function str_starts_with(string $haystack, string $needle): bool { return p\Php80::str_starts_with($haystack, $needle); }
+        function str_starts_with(string $haystack, string $needle) /*: bool */ { return p\Php80::str_starts_with($haystack, $needle); }
     }

     if (!function_exists('str_ends_with')) {
-        function str_ends_with(string $haystack, string $needle): bool { return p\Php80::str_ends_with($haystack, $needle); }
+        function str_ends_with(string $haystack, string $needle) /*: bool */ { return p\Php80::str_ends_with($haystack, $needle); }
     }

     if (!defined('FILTER_VALIDATE_BOOL') && defined('FILTER_VALIDATE_BOOLEAN')) {
@@ -37,6 +37,6 @@ if (PHP_VERSION_ID < 80000) {
     }

     if (!function_exists('get_debug_type')) {
-        function get_debug_type($value): string { return p\Php80::get_debug_type($value); }
+        function get_debug_type($value) /*: string */ { return p\Php80::get_debug_type($value); }
     }
 }
diff --git a/src/bootstrap.php b/src/bootstrap.php
index 6d92ed0..4e6519e 100644
--- a/src/bootstrap.php
+++ b/src/bootstrap.php
@@ -9,6 +9,6 @@
  * file that was distributed with this source code.
  */

-if (PHP_VERSION_ID < 80000 && PHP_VERSION_ID >= 70000) {
+if (PHP_VERSION_ID < 80000 /* && PHP_VERSION_ID >= 70000 */ ) {
     require __DIR__.'/Php80/bootstrap.php';
 }