Jon Pretty

Make it clear in the talk how awfully slow automatic generic derivation in Scala is, please

I'm going to make it fast.

Is ~10x Shapeless's derivation speed fast enough for you?

It's a great step towards the right direction, certainly! I feel the deriv. times could be addressed in the compiler more systematically.

There's not much more the compiler can do: My ASTs are semantically quite minimal yet most of the compile time is still typechecking them.

The compiler may help with the implicit search and AST generation, but those ASTs are fundamentally large and therefore slow to typecheck.

I would need to have a closer look, but I can tell you I'm tired of benchmark the typer and 90% of time is in implicit search, no asts.

Generally, simple AST typechecking is really cheap. The cost of implicit search dominates compile times in shapeless and Circe.