Deal with null type in PHP8.2 (#1205)

Signed-off-by: Nathanael Esayeas <nathanael.esayeas@protonmail.com>

library/Mockery/Reflector.php

@@ -220,6 +220,10 @@ private static function formatNullableType($typeHint)
             return sprintf('?%s', $typeHint);
         }
 
-        return $typeHint === 'mixed' ? 'mixed' : sprintf('%s|null', $typeHint);
+        if ($typeHint === 'null' || $typeHint === 'mixed') {
+            return $typeHint;
+        }
+
+        return sprintf('%s|null', $typeHint);
     }
 }

tests/PHP82/Php82LanguageFeaturesTest.php

@@ -0,0 +1,28 @@
+<?php
+
+namespace test\Mockery;
+
+use Mockery;
+use Mockery\Adapter\Phpunit\MockeryTestCase;
+
+/**
+ * @requires PHP 8.2.0-dev
+ */
+class Php82LanguageFeaturesTest extends MockeryTestCase
+{
+    /** @test */
+    public function it_can_mock_an_class_with_null_return_type()
+    {
+        $mock = Mockery::mock(HasNullReturnType::class);
+
+        $this->assertInstanceOf(HasNullReturnType::class, $mock);
+    }
+}
+
+class HasNullReturnType
+{
+    public function getChildren(): null
+    {
+        return null;
+    }
+}