https://twitter.com/tpolecat/status/1340380781538062341

steps

organization := "example"
scalaVersion := "2.13.4"
name := "hello"
lazy val root = (project in file("."))
lazy val core = (project in file("core"))
lazy val app = (project in file("app"))

problem

I've been trying to discourage people from using bare .sbt build definition, but people do and often it leads to confusion since they tend to assume that the scalaVersion above would carry over to the subprojects.

expectation

Now that the ecosystem has largely migrated to sbt 1.x, we can cut off the vestige of sbt 0.13 era and deprecate bare settings against implicit root subproject in the proper build.