[Feature] Implement parameter widening feature for generated code (#380)

src/Aop/Features.php

@@ -40,4 +40,11 @@ interface Features
      * This flag is usable for read-only file systems (GAE, phar, etc)
      */
     const PREBUILT_CACHE = 64;
+
+    /**
+     * Enables usage of parameter widening for PHP>=7.2.0
+     *
+     * @see https://wiki.php.net/rfc/parameter-no-type-variance
+     */
+    const PARAMETER_WIDENING = 128;
 }

src/Instrument/Transformer/WeavingTransformer.php

@@ -13,6 +13,7 @@
 
 use Go\Aop\Advisor;
 use Go\Aop\Aspect;
+use Go\Aop\Features;
 use Go\Aop\Framework\AbstractJoinpoint;
 use Go\Core\AdviceMatcher;
 use Go\Core\AspectContainer;
@@ -38,6 +39,13 @@ class WeavingTransformer extends BaseSourceTransformer
      */
     protected $adviceMatcher;
 
+    /**
+     * Should we use parameter widening for our decorators
+     *
+     * @var bool
+     */
+    protected $useParameterWidening = false;
+
     /**
      * @var CachePathManager
      */
@@ -68,6 +76,9 @@ public function __construct(
         $this->adviceMatcher    = $adviceMatcher;
         $this->cachePathManager = $cachePathManager;
         $this->aspectLoader     = $loader;
+        if (PHP_VERSION_ID >= 70200) {
+            $this->useParameterWidening = $kernel->hasFeature(Features::PARAMETER_WIDENING);
+        }
     }
 
     /**
@@ -144,8 +155,8 @@ private function processSingleClass(array $advisors, StreamMetaData $metadata, R
 
         // Prepare child Aop proxy
         $child = $class->isTrait()
-            ? new TraitProxy($class, $advices)
-            : new ClassProxy($class, $advices);
+            ? new TraitProxy($class, $advices, $this->useParameterWidening)
+            : new ClassProxy($class, $advices, $this->useParameterWidening);
 
         // Set new parent name instead of original
         $child->setParentName($newClassName);

src/Proxy/AbstractProxy.php

@@ -43,14 +43,25 @@ abstract class AbstractProxy
      */
     protected static $staticLsbExpression = 'static::class';
 
+    /**
+     * Whether or not proxy should use parameter widening
+     *
+     * @see https://wiki.php.net/rfc/parameter-no-type-variance
+     *
+     * @var bool
+     */
+    private $useParameterWidening;
+
     /**
      * Constructs an abstract proxy class
      *
      * @param array $advices List of advices
+     * @param bool $useParameterWidening Should proxy use parameter widening feature
      */
-    public function __construct(array $advices = [])
+    public function __construct(array $advices = [], bool $useParameterWidening = false)
     {
-        $this->advices = $this->flattenAdvices($advices);
+        $this->advices              = $this->flattenAdvices($advices);
+        $this->useParameterWidening = $useParameterWidening;
     }
 
     /**
@@ -105,7 +116,7 @@ protected function getParameterCode(ReflectionParameter $parameter): string
     {
         $type = '';
         $reflectionType = $parameter->getType();
-        if ($reflectionType) {
+        if ($reflectionType !== null && $this->useParameterWidening === false) {
             $nullablePrefix = (PHP_VERSION_ID >= 70100 && $reflectionType->allowsNull()) ? '?' : '';
             $nsPrefix       = $reflectionType->isBuiltin() ? '' : '\\';
             $type           = $nullablePrefix . $nsPrefix . ltrim((string) $reflectionType, '\\');

src/Proxy/ClassProxy.php

@@ -114,12 +114,13 @@ class ClassProxy extends AbstractProxy
      *
      * @param ReflectionClass $parent Parent class reflection
      * @param array|Advice[][] $classAdvices List of advices for class
+     * @param bool $useParameterWidening Enables usage of parameter widening feature
      *
      * @throws \InvalidArgumentException if there are unknown type of advices
      */
-    public function __construct(ReflectionClass $parent, array $classAdvices)
+    public function __construct(ReflectionClass $parent, array $classAdvices, bool $useParameterWidening)
     {
-        parent::__construct($classAdvices);
+        parent::__construct($classAdvices, $useParameterWidening);
 
         $this->class           = $parent;
         $this->name            = $parent->getShortName();