In PHP, traits serve as reusable blocks of code that can be included in multiple classes. This approach allows developers to share methods across various classes without the limitations of inheritance, which only supports a single parent class. However, there is a drawback: traits cannot directly reference constants defined within the classes that incorporate them. This limitation exists because constants are specific to each class and are not inherently visible to the trait itself.

In your original setup:

You have a class named MyClass that defines a constant MY_CONST.

You want to use this constant inside a trait named MyTrait.

However, accessing MY_CONST directly from the trait results in an error unless the class name is hardcoded, which is restrictive and reduces the flexibility of the trait.

Solution Approach To address this issue, we can introduce an abstract method in the trait. An abstract method contains no implementation but compels any class using the trait to define it. By doing so, we create a way for the class to pass the constant's value to the trait, without the trait requiring direct access to the constant itself.