Fix #520: Error if an optional parameter is before required parameters

src/Definition/Resolver/ParameterResolver.php

@@ -59,7 +59,7 @@ public function resolveParameters(
                 $value = &$definitionParameters[$index];
             } else {
                 // If the parameter is optional and wasn't specified, we take its default value
-                if ($parameter->isOptional()) {
+                if ($parameter->isDefaultValueAvailable() || $parameter->isOptional()) {
                     $args[] = $this->getParameterDefaultValue($parameter, $method);
                     continue;
                 }

tests/IntegrationTest/Definitions/AutowireDefinition/OptionalParameterFollowedByRequiredParameter.php

@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+namespace DI\Test\IntegrationTest\Definitions\AutowireDefinition;
+
+class OptionalParameterFollowedByRequiredParameter
+{
+    public $first;
+    public $second;
+
+    public function __construct($first = null, \stdClass $second)
+    {
+        $this->first = $first;
+        $this->second = $second;
+    }
+}

tests/IntegrationTest/Definitions/AutowireDefinitionTest.php

@@ -6,6 +6,7 @@
 
 use DI\ContainerBuilder;
 use DI\Test\IntegrationTest\BaseContainerTest;
+use DI\Test\IntegrationTest\Definitions\AutowireDefinition\OptionalParameterFollowedByRequiredParameter;
 use DI\Test\IntegrationTest\Definitions\AutowireDefinitionTest\ConstructorInjection;
 use DI\Test\IntegrationTest\Definitions\AutowireDefinitionTest\LazyService;
 use DI\Test\IntegrationTest\Definitions\AutowireDefinitionTest\NullableConstructorParameter;
@@ -307,6 +308,19 @@ public function test_autowire_lazy_object(ContainerBuilder $builder)
         self::assertEquals('bar', $object->bar);
         self::assertTrue($object->isProxyInitialized());
     }
+
+    /**
+     * @dataProvider provideContainer
+     */
+    public function test_optional_parameter_followed_by_required_parameters(ContainerBuilder $builder)
+    {
+        $container = $builder->build();
+
+        $object = $container->get(OptionalParameterFollowedByRequiredParameter::class);
+
+        self::assertNull($object->first);
+        self::assertInstanceOf(\stdClass::class, $object->second);
+    }
 }
 
 namespace DI\Test\IntegrationTest\Definitions\AutowireDefinitionTest;