[8.x] Fix attribute casting (#40245)

* Add failing test

* Fix attribute casting issue

* Update DatabaseEloquentModelAttributeCastingTest.php

Author: driesvints

src/Illuminate/Database/Eloquent/Concerns/HasAttributes.php

@@ -571,8 +571,7 @@ public function hasAttributeGetMutator($key)
 
         return static::$attributeMutatorCache[get_class($this)][$key] = $returnType &&
                     $returnType instanceof ReflectionNamedType &&
-                    $returnType->getName() === Attribute::class &&
-                    is_callable($this->{$method}()->get);
+                    $returnType->getName() === Attribute::class;
     }
 
     /**
@@ -949,8 +948,7 @@ public function hasAttributeSetMutator($key)
 
         return static::$setAttributeMutatorCache[$class][$key] = $returnType &&
                     $returnType instanceof ReflectionNamedType &&
-                    $returnType->getName() === Attribute::class &&
-                    is_callable($this->{$method}()->set);
+                    $returnType->getName() === Attribute::class;
     }
 
     /**

tests/Integration/Database/DatabaseEloquentModelAttributeCastingTest.php

@@ -142,6 +142,8 @@ public function testOneWayCasting()
     {
         $model = new TestEloquentModelWithAttributeCast;
 
+        $this->assertNull($model->password);
+
         $model->password = 'secret';
 
         $this->assertEquals(hash('sha256', 'secret'), $model->password);