quasar/target/streams/compile/bgRun/_global/streams/out

[error] java.lang.RuntimeException: No main class detected.
[error] at scala.sys.package$.error(package.scala:30)
[error] at sbt.Defaults$.$anonfun$bgRunTask$4(Defaults.scala:1477)
[error] at scala.Option.getOrElse(Option.scala:189)
[error] at sbt.Defaults$.$anonfun$bgRunTask$3(Defaults.scala:1477)
[error] at scala.Function1.$anonfun$compose$1(Function1.scala:49)
[error] at sbt.internal.util.$tilde$greater.$anonfun$$u2219$1(TypeFunctions.scala:62)
[error] at sbt.std.Transform$$anon$4.work(Transform.scala:67)
[error] at sbt.Execute.$anonfun$submit$2(Execute.scala:281)
[error] at sbt.internal.util.ErrorHandling$.wideConvert(ErrorHandling.scala:19)
[error] at sbt.Execute.work(Execute.scala:290)
[error] at sbt.Execute.$anonfun$submit$1(Execute.scala:281)
[error] at sbt.ConcurrentRestrictions$$anon$4.$anonfun$submitValid$1(ConcurrentRestrictions.scala:178)
[error] at sbt.CompletionService$$anon$2.call(CompletionService.scala:37)
[error] at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
[error] at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
[error] at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
[error] at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
[error] at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
[error] at java.base/java.lang.Thread.run(Thread.java:834)
[error] (Compile / bgRun) No main class detected.