5 files changed, 58 insertions, 1 deletions
diff --git a/src/main/scala/firrtl/passes/CheckChirrtl.scala b/src/main/scala/firrtl/passes/CheckChirrtl.scala
index 579dba30..9903f445 100644
--- a/src/main/scala/firrtl/passes/CheckChirrtl.scala
+++ b/src/main/scala/firrtl/passes/CheckChirrtl.scala
@@ -5,9 +5,12 @@ package firrtl.passes
 import firrtl.Transform
 import firrtl.ir._
 import firrtl.options.Dependency
+import firrtl.stage.transforms.CheckScalaVersion
 
 object CheckChirrtl extends Pass with CheckHighFormLike {
 
+  override def prerequisites = Dependency[CheckScalaVersion] :: Nil
+
   override val optionalPrerequisiteOf = firrtl.stage.Forms.ChirrtlForm ++
     Seq( Dependency(CInferTypes),
          Dependency(CInferMDir),
diff --git a/src/main/scala/firrtl/stage/FirrtlAnnotations.scala b/src/main/scala/firrtl/stage/FirrtlAnnotations.scala
index 91c5609b..d587fd8c 100644
--- a/src/main/scala/firrtl/stage/FirrtlAnnotations.scala
+++ b/src/main/scala/firrtl/stage/FirrtlAnnotations.scala
@@ -222,3 +222,18 @@ case class FirrtlCircuitAnnotation(circuit: Circuit) extends NoTargetAnnotation
   override lazy val hashCode: Int = circuit.hashCode
 
 }
+
+/** Suppresses warning about Scala 2.11 deprecation
+  *
+  *  - set with `--Wno-scala-version-warning`
+  */
+case object SuppressScalaVersionWarning extends NoTargetAnnotation with FirrtlOption with HasShellOptions {
+  def longOption: String = "Wno-scala-version-warning"
+  val options = Seq(
+    new ShellOption[Unit](
+      longOption      = longOption,
+      toAnnotationSeq = { _ => Seq(this) },
+      helpText        = "Suppress Scala 2.11 deprecation warning (ignored in Scala 2.12+)"
+    )
+  )
+}
diff --git a/src/main/scala/firrtl/stage/FirrtlCli.scala b/src/main/scala/firrtl/stage/FirrtlCli.scala
index be1100c3..39b89bea 100644
--- a/src/main/scala/firrtl/stage/FirrtlCli.scala
+++ b/src/main/scala/firrtl/stage/FirrtlCli.scala
@@ -19,7 +19,8 @@ trait FirrtlCli { this: Shell =>
        RunFirrtlTransformAnnotation,
        firrtl.EmitCircuitAnnotation,
        firrtl.EmitAllModulesAnnotation,
-       NoCircuitDedupAnnotation )
+       NoCircuitDedupAnnotation,
+       SuppressScalaVersionWarning)
     .map(_.addOptions(parser))
 
   phases.DriverCompatibility.TopNameAnnotation.addOptions(parser)
diff --git a/src/main/scala/firrtl/stage/package.scala b/src/main/scala/firrtl/stage/package.scala
index e9cf3fb4..123c763a 100644
--- a/src/main/scala/firrtl/stage/package.scala
+++ b/src/main/scala/firrtl/stage/package.scala
@@ -33,6 +33,7 @@ package object stage {
           case InfoModeAnnotation(i)             => c.copy(infoModeName = i)
           case FirrtlCircuitAnnotation(cir)      => c.copy(firrtlCircuit = Some(cir))
           case a : CompilerAnnotation => logger.warn(s"Use of CompilerAnnotation is deprecated. Ignoring $a") ; c
+          case SuppressScalaVersionWarning       => c
         }
       }
   }
diff --git a/src/main/scala/firrtl/stage/transforms/CheckScalaVersion.scala b/src/main/scala/firrtl/stage/transforms/CheckScalaVersion.scala
new file mode 100644
index 00000000..a7127dba
--- /dev/null
+++ b/src/main/scala/firrtl/stage/transforms/CheckScalaVersion.scala
@@ -0,0 +1,37 @@
+// See LICENSE for license details.
+
+package firrtl.stage.transforms
+
+import firrtl.{BuildInfo, CircuitState, DependencyAPIMigration, Transform}
+import firrtl.stage.SuppressScalaVersionWarning
+import firrtl.options.StageUtils.dramaticWarning
+
+object CheckScalaVersion {
+  def migrationDocumentLink: String = "https://www.chisel-lang.org/chisel3/upgrading-from-scala-2-11.html"
+
+  private def getScalaMajorVersion: Int = {
+    val "2" :: major :: _ :: Nil = BuildInfo.scalaVersion.split("\\.").toList
+    major.toInt
+  }
+
+  final def deprecationMessage(version: String, option: String) =
+    s"""|FIRRTL support for Scala $version is deprecated, please upgrade to Scala 2.12.
+        |  Migration guide: $migrationDocumentLink
+        |  Suppress warning with '$option'""".stripMargin
+
+}
+
+class CheckScalaVersion extends Transform with DependencyAPIMigration {
+  import CheckScalaVersion._
+
+  override def invalidates(a: Transform) = false
+
+  def execute(state: CircuitState): CircuitState = {
+    def suppress = state.annotations.contains(SuppressScalaVersionWarning)
+    if (getScalaMajorVersion == 11 && !suppress) {
+      val option = s"--${SuppressScalaVersionWarning.longOption}"
+      dramaticWarning(deprecationMessage("2.11", option))
+    }
+    state
+  }
+}