sbt expect a Scala compiler to have a "default" configuration

Author: smarter

project/Build.scala

@@ -5,6 +5,8 @@ import java.nio.channels.FileLock
 import scala.reflect.io.Path
 
 object DottyBuild extends Build {
+  // Dummy configuration needed by sbt to use dotty as a compiler
+  val Default = config("default") extend(Runtime)
 
   val travisMemLimit = List("-Xmx1g", "-Xss2m")
 
@@ -129,7 +131,7 @@ object DottyBuild extends Build {
   ) ++ addCommandAlias("partest", ";test:package;package;test:runMain dotc.build;lockPartestFile;test:test;runPartestRunner") ++
        addCommandAlias("partest-only", ";test:package;package;test:runMain dotc.build;lockPartestFile;test:test-only dotc.tests;runPartestRunner")
 
-  lazy val dotty = Project(id = "dotty", base = file("."), settings = defaults)
+  lazy val dotty = Project(id = "dotty", base = file("."), settings = defaults, configurations = Seq(Default))
 
   lazy val benchmarkSettings = Defaults.coreDefaultSettings ++ Seq(