hearth-def-caching

To cache type-class instances in Scala and avoid recomputation, use a shared ValDefsCache across multiple methods, applying forwardDeclare and buildCachedWith to materialize cached defs under a controlled scope.

Recursive type-class derivation in Scala macros requires forward-declaring definitions, building cached method bodies with buildCachedWith, and hoisting defs via toValDefs.use to emit top-level defs alongside the final instance.

Yes, independent parts of type-class derivations can be parallelized using parTuple, provided you carefully match arity and wrap the output correctly via toValDefs.use to emit top-level defs.

Cached type-class derivation handles Scala 2 and Scala 3 interop, allowing you to generate multi-method instances with shared ValDefsCache while maintaining safe sharing of derived definitions across complex structures.

Multi-method type-class derivation duplicates method bodies when a single shared ValDefsCache is not used, making it necessary to hoist defs via toValDefs.use to emit top-level defs and maintain consistency.