kindlings-factory-instance

Anonymous class emissions in macro typeclass derivations occur when code generation creates a new class per type. Replacing these with reusable factory methods reduces generated class files and speeds up compilation.

Refactor macro code by replacing new TypeClass[A] { ... } emissions with calls to a centralized factory like CatsDerivationFactories.instance[A](...), which generates lambdas instead of per-type anonymous classes.

Yes, factory-based derivation supports polymorphic type classes of kind * -> *. It uses Witness types to enable erasure-based factories that work across all A and F[_] instances.

Monomorphic type classes of kind * use ordinary lambdas to create final instances in a single static factory, while polymorphic type classes of kind * -> * use Witness types for erasure-based factory compatibility.

Replacing per-type anonymous classes with single reusable factory methods reduces the number of generated .class files. This reduction in runtime footprint speeds up compilation when deriving type classes for many types.

Factory-based typeclass derivation requires implementing factories in an internal runtime module and updating macro code generation. It relies on erasure-based factories with Witness types for polymorphic support, which may constrain complex type boundaries.