How to "re-run with -deprecation for details" in sbt?

sbt shell

While in sbt shell (if you don't want to change your build.sbt):

$ sbt
> set ThisBuild/scalacOptions ++= Seq("-unchecked", "-deprecation")
> compile
> exit

Due to in ThisBuild, set applies the settings to all sub-projects, as well.

You could also run the above as a single command on command line.

sbt '; set ThisBuild/scalacOptions ++= Seq("-unchecked", "-deprecation") ; compile'

The trick is to use ; (semicolons) to separate commands and ' (ticks) to include all ;-separated commands as a single argument to sbt.

Instead of ThisBuild/scalacOptions use scalacOptions in ThisBuild

scalacOptions := Seq("-unchecked", "-deprecation")

Add this setting to your build.sbt, and, if you have a multi-module project, add it to every project's settings.