Fix problem with not loaded return type

Author: akondas

spec/Proget/Tests/PHPStan/PhpSpec/FooSpec.php

@@ -21,6 +21,11 @@ public function it_is_initializable(): void
         $this->shouldHaveType(Foo::class);
     }
 
+    public function it_should_return_empty_string(): void
+    {
+        $this->foo()->shouldBe('');
+    }
+
     public function it_should_make_baz(Baz $baz): void
     {
         $baz->make()->willReturn(123);

src/Reflection/ObjectBehaviorMethodsClassReflectionExtension.php

@@ -78,12 +78,13 @@ public function getMethod(ClassReflection $classReflection, string $methodName):
 
     private function replaceReturnType(MethodReflection $method): void
     {
+        $method->getVariants();
         $methodReflection = new \ReflectionClass($method);
-        $returnType = $methodReflection->getProperty('nativeReturnType');
+        $returnType = $methodReflection->getProperty('returnType');
         $returnType->setAccessible(true);
         $returnType->setValue($method, new SubjectType($returnType->getValue($method)));
 
-        $nativeReturnType = $methodReflection->getProperty('returnType');
+        $nativeReturnType = $methodReflection->getProperty('nativeReturnType');
         $nativeReturnType->setAccessible(true);
         $nativeReturnType->setValue($method, new SubjectType($nativeReturnType->getValue($method)));