Re-run Compilation with Deprecations Turned on from within SBT

Often while compiling some Scala project from with SBT, I’d see the following error:

re-run with -deprecation for details

And then I would have to go and update my build.sbt file with with following:

scalacOptions ++= Seq(
                      "-deprecation",
                      //other options
                   )

and then relaunch SBT and perform the compilation again. That’s a little painful.

I stumbled across this incantation to achieve the same result from right within SBT:

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

You can then kick off a new compilation with:

;clean;compile

to see any deprecation warnings. And that’s all there is to it. :)