…erty promotion in the code exampleAdding visibility on the constructor parameter results in constructor property promotion and in redeclaring the property in a way which is incompatible with the declaration from the trait, resulting in a fatal error if the example is used as is.For reference:https://www.php.net/manual/en/language.oop5.traits.php#language.oop5.traits.properties.exampleInstead, I think the visibility should be removed in order to prevent redeclaration (and incompatibility with the property from the trait), and just use dependency injection and overwrite the default value so that the trait won't create a new instance for the $lockFactory.