How To Get Depreciation Warnings With Chisel3

I'm starting this to document my efforts to learn to use Chisel and to, hopeully, help other people avoid the problems I've had.

When you run Chisel from sbt, you might get a warning like::

[warn] there were 6 deprecation warnings; re-run with -deprecation for details

[warn] there were 27 feature warnings; re-run with -feature for details

[warn] two warnings found

I spent a while trying to find out how to pass this argument to the Chisel environment. The source of my confusion was that this is an argument passed to the scala compiler itself. You can pass these arguments by add this to your build.sbt:

scalacOptions in ThisBuild ++= Seq("-feature", "-deprecation")

This will give you a bunch of feature warnings, mosly about reflective method calls. I'm not yet sure what that means and if it's best to ignore these warnings.