deprecate CrossVersion.Disabled

build.sbt

@@ -100,6 +100,10 @@ lazy val lmCore = (project in file("core"))
       scalaCheck % Test,
       scalaVerify % Test,
     ),
+    libraryDependencies ++= (scalaVersion.value match {
+      case v if v.startsWith("2.12.") => List(compilerPlugin(silencerPlugin))
+      case _                          => List()
+    }),
     libraryDependencies += scalaXml,
     resourceGenerators in Compile += Def
       .task(

core/src/main/scala/sbt/librarymanagement/CrossVersionExtra.scala

@@ -8,6 +8,10 @@ final case class ScalaVersion(full: String, binary: String)
 private[librarymanagement] abstract class CrossVersionFunctions {
 
   /** Compatibility with 0.13 */
+  @deprecated(
+    "use CrossVersion.disabled instead. prior to sbt 1.3.0, Diabled did not work without apply(). sbt/sbt#4977",
+    "1.3.0"
+  )
   final val Disabled = sbt.librarymanagement.Disabled
   final val Binary = sbt.librarymanagement.Binary
   final val Constant = sbt.librarymanagement.Constant
@@ -37,7 +41,7 @@ private[librarymanagement] abstract class CrossVersionFunctions {
   def binary: CrossVersion = Binary()
 
   /** Disables cross versioning for a module. */
-  def disabled: CrossVersion = Disabled
+  def disabled: CrossVersion = sbt.librarymanagement.Disabled
 
   /** Cross-versions a module with a constant string (typically the binary Scala version).  */
   def constant(value: String): CrossVersion = Constant(value)

core/src/test/scala/example/tests/CrossVersionCompatTest.scala

@@ -2,7 +2,9 @@ package example.tests
 
 import sbt.librarymanagement.{ CrossVersion, Disabled }
 import verify.BasicTestSuite
+import com.github.ghik.silencer.silent
 
+@silent
 object CrossVersionCompatTest extends BasicTestSuite {
   test("CrossVersion.Disabled is typed to be Disabled") {
     assert(CrossVersion.Disabled match {

project/Dependencies.scala

@@ -61,4 +61,5 @@ object Dependencies {
   }
   val gigahorseOkhttp = "com.eed3si9n" %% "gigahorse-okhttp" % "0.5.0"
   val okhttpUrlconnection = "com.squareup.okhttp3" % "okhttp-urlconnection" % "3.7.0"
+  val silencerPlugin = "com.github.ghik" %% "silencer-plugin" % "1.4.1"
 }