enable `-P:semanticdb:synthetics:on` in sbt-typelevel-scalafix?

[armanbilge]

This is needed for some rules, but not all. Should we enable it by default? At the very least maybe expose a setting to make it easy to switch on. (And always the question: why doesn't sbt-scalafix do this itself?)

[rossabaker]

What is the drawback? Compilation time?

[armanbilge]

Maybe not even that. The semantic db docs say this for the option.

Specifies whether to save some of the compiler-synthesized code in the currently unspecified TextDocument.synthetics section (on for yes, off for no).

https://scalameta.org/docs/semanticdb/guide.html#scalac-compiler-plugin

That seems harmless enough?

I'm just confused/frustrated why we have to enable so much stuff that seems like it should be enabled in sbt-scalafix itself.