Re implicits and their interplay with macros: Achieving 3.2x Faster Scala Compile Time

Diagnostics:

- A method takes an implicit parameter to be filled in by the compiler

- the Scala compiler synthesizes an argument for that parameter using macros

- instead of using an existing value in the implicit scope

Conclusion: that's why a small source file took so long to typecheck.

Details at https://jobs.zalando.com/tech/blog/achieving-3.2x-faster-sca...