Why is inheritance avoided in structural types?

In Swift's struct types, inheritance is not supported for several reasons:

• Avoiding complexity of hierarchies. Structs are intended for simple, lightweight data types, and inheritance could complicate their use and understanding.

• Safety and predictability. The absence of inheritance prevents issues with state changes through subclasses, increasing code reliability.

• Copy by value. Structs are copied when passed around, and inheritance is related to reference types, which can lead to unexpected side effects.

• Performance. The lack of inheritance allows the compiler to optimize the code better, as there is no need to support a dynamic method dispatcher.

Ultimately, protocols and composition are used instead of inheritance for extensibility and code reuse in structs.