Remove Scala 2.11 (#2062)

7 files changed, 21 insertions, 86 deletions

diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 134670b8..f6af7cbd 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        scala: [2.13.4, 2.12.13, 2.11.12]
+        scala: [2.13.4, 2.12.13]
     container:
       image: ucbbar/chisel3-tools
       options: --user github --entrypoint /bin/bash
diff --git a/build.sbt b/build.sbt
index d779920b..f047f35b 100644
--- a/build.sbt
+++ b/build.sbt
@@ -2,24 +2,10 @@
 
 enablePlugins(SiteScaladocPlugin)
 
-def javacOptionsVersion(scalaVersion: String): Seq[String] = {
-  Seq() ++ {
-    // Scala 2.12 requires Java 8, but we continue to generate
-    //  Java 7 compatible code until we need Java 8 features
-    //  for compatibility with old clients.
-    CrossVersion.partialVersion(scalaVersion) match {
-      case Some((2, scalaMajor: Long)) if scalaMajor < 12 =>
-        Seq("-source", "1.7", "-target", "1.7")
-      case _ =>
-        Seq("-source", "1.8", "-target", "1.8")
-    }
-  }
-}
-
 lazy val commonSettings = Seq(
   organization := "edu.berkeley.cs",
   scalaVersion := "2.12.13",
-  crossScalaVersions := Seq("2.13.4", "2.12.13", "2.11.12")
+  crossScalaVersions := Seq("2.13.4", "2.12.13")
 )
 
 lazy val isAtLeastScala213 = Def.setting {
@@ -39,7 +25,8 @@ lazy val firrtlSettings = Seq(
     "-language:implicitConversions",
     "-Yrangepos",          // required by SemanticDB compiler plugin
   ),
-  javacOptions ++= javacOptionsVersion(scalaVersion.value),
+  // Always target Java8 for maximum compatibility
+  javacOptions ++= Seq("-source", "1.8", "-target", "1.8"),
   libraryDependencies ++= Seq(
     "org.scala-lang" % "scala-reflect" % scalaVersion.value,
     "org.scalatest" %% "scalatest" % "3.2.0" % "test",
@@ -142,22 +129,11 @@ lazy val publishSettings = Seq(
 )
 
 
-def scalacDocOptionsVersion(scalaVersion: String): Seq[String] = {
-  Seq() ++ {
-    // If we're building with Scala > 2.11, enable the compile option
-    //  to flag warnings as errors. This must be disabled for 2.11 since
-    //  references to the Java class library from Java 9 on generate warnings.
-    //  https://github.com/scala/bug/issues/10675
-    CrossVersion.partialVersion(scalaVersion) match {
-      case Some((2, scalaMajor: Long)) if scalaMajor < 12 => Seq()
-      case _ => Seq("-Xfatal-warnings")
-    }
-  }
-}
 lazy val docSettings = Seq(
   doc in Compile := (doc in ScalaUnidoc).value,
   autoAPIMappings := true,
   scalacOptions in Compile in doc ++= Seq(
+    "-Xfatal-warnings",
     "-feature",
     "-diagrams",
     "-diagrams-max-classes", "25",
@@ -175,7 +151,7 @@ lazy val docSettings = Seq(
         }
       s"https://github.com/chipsalliance/firrtl/tree/$branch€{FILE_PATH_EXT}#L€{FILE_LINE}"
     }
-  ) ++ scalacDocOptionsVersion(scalaVersion.value)
+  )
 )
 
 lazy val firrtl = (project in file("."))
diff --git a/build.sc b/build.sc
index ebef2b3d..89796964 100644
--- a/build.sc
+++ b/build.sc
@@ -7,7 +7,7 @@ import mill.modules.Util
 import $ivy.`com.lihaoyi::mill-contrib-buildinfo:$MILL_VERSION`
 import mill.contrib.buildinfo.BuildInfo
 
-object firrtl extends mill.Cross[firrtlCrossModule]("2.11.12", "2.12.12", "2.13.2")
+object firrtl extends mill.Cross[firrtlCrossModule]("2.12.12", "2.13.2")
 
 class firrtlCrossModule(val crossScalaVersion: String) extends CrossSbtModule with PublishModule with BuildInfo {
   override def millSourcePath = super.millSourcePath / os.up
@@ -21,10 +21,7 @@ class firrtlCrossModule(val crossScalaVersion: String) extends CrossSbtModule wi
     Some("firrtl.stage.FirrtlMain")
   }
 
-  private def javacCrossOptions = majorVersion match {
-    case i if i < 12 => Seq("-source", "1.7", "-target", "1.7")
-    case _ => Seq("-source", "1.8", "-target", "1.8")
-  }
+  private def javacCrossOptions = Seq("-source", "1.8", "-target", "1.8")
 
   override def scalacOptions = T {
     super.scalacOptions() ++ Seq(
@@ -56,16 +53,11 @@ class firrtlCrossModule(val crossScalaVersion: String) extends CrossSbtModule wi
   }
 
   object test extends Tests {
-    private def ivyCrossDeps = majorVersion match {
-      case i if i < 12 => Agg(ivy"junit:junit:4.13.1")
-      case _ => Agg()
-    }
-
     override def ivyDeps = T {
       Agg(
         ivy"org.scalatest::scalatest:3.2.0",
         ivy"org.scalatestplus::scalacheck-1-14:3.1.3.0"
-      ) ++ ivyCrossDeps
+      )
     }
 
     def testFrameworks = T {
diff --git a/src/main/scala/firrtl/stage/FirrtlAnnotations.scala b/src/main/scala/firrtl/stage/FirrtlAnnotations.scala
index 7d0d237a..26655efd 100644
--- a/src/main/scala/firrtl/stage/FirrtlAnnotations.scala
+++ b/src/main/scala/firrtl/stage/FirrtlAnnotations.scala
@@ -255,13 +255,18 @@ case class FirrtlCircuitAnnotation(circuit: Circuit) extends NoTargetAnnotation
   *
   *  - set with `--warn:no-scala-version-deprecation`
   */
+@deprecated("Support for Scala 2.11 has been dropped, this object no longer does anything", "FIRRTL 1.5")
 case object WarnNoScalaVersionDeprecation extends NoTargetAnnotation with FirrtlOption with HasShellOptions {
   def longOption: String = "warn:no-scala-version-deprecation"
   val options = Seq(
     new ShellOption[Unit](
       longOption = longOption,
-      toAnnotationSeq = { _ => Seq(this) },
-      helpText = "Suppress Scala 2.11 deprecation warning (ignored in Scala 2.12+)"
+      toAnnotationSeq = { _ =>
+        val msg = s"'$longOption' no longer does anything and will be removed in FIRRTL 1.6"
+        firrtl.options.StageUtils.dramaticWarning(msg)
+        Seq(this)
+      },
+      helpText = "(deprecated, this option does nothing)"
     )
   )
 }
diff --git a/src/main/scala/firrtl/stage/transforms/CheckScalaVersion.scala b/src/main/scala/firrtl/stage/transforms/CheckScalaVersion.scala
index 9d894905..6ed900f1 100644
--- a/src/main/scala/firrtl/stage/transforms/CheckScalaVersion.scala
+++ b/src/main/scala/firrtl/stage/transforms/CheckScalaVersion.scala
@@ -6,14 +6,10 @@ import firrtl.{BuildInfo, CircuitState, DependencyAPIMigration, Transform}
 import firrtl.stage.WarnNoScalaVersionDeprecation
 import firrtl.options.StageUtils.dramaticWarning
 
+@deprecated("Support for 2.11 has been dropped, this logic no longer does anything", "FIRRTL 1.5")
 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
@@ -21,17 +17,10 @@ object CheckScalaVersion {
 
 }
 
+@deprecated("Support for 2.11 has been dropped, this transform no longer does anything", "FIRRTL 1.5")
 class CheckScalaVersion extends Transform with DependencyAPIMigration {
-  import CheckScalaVersion._
 
   override def invalidates(a: Transform) = false
 
-  def execute(state: CircuitState): CircuitState = {
-    def suppress = state.annotations.contains(WarnNoScalaVersionDeprecation)
-    if (getScalaMajorVersion == 11 && !suppress) {
-      val option = s"--${WarnNoScalaVersionDeprecation.longOption}"
-      dramaticWarning(deprecationMessage("2.11", option))
-    }
-    state
-  }
+  def execute(state: CircuitState): CircuitState = state
 }
diff --git a/src/test/scala/firrtl/backends/experimental/smt/end2end/SMTCompilationTest.scala b/src/test/scala/firrtl/backends/experimental/smt/end2end/SMTCompilationTest.scala
index 72949830..f846e19c 100644
--- a/src/test/scala/firrtl/backends/experimental/smt/end2end/SMTCompilationTest.scala
+++ b/src/test/scala/firrtl/backends/experimental/smt/end2end/SMTCompilationTest.scala
@@ -15,8 +15,7 @@ import scala.sys.process.{Process, ProcessLogger}
 class SMTCompilationTest extends AnyFlatSpec with LazyLogging {
   it should "generate valid SMTLib for AddNot" taggedAs (RequiresZ3) in { compileAndParse("AddNot") }
   it should "generate valid SMTLib for FPU" taggedAs (RequiresZ3) in { compileAndParse("FPU") }
-  // we get a stack overflow in Scala 2.11 because of a deeply nested and(...) expression in the sequencer
-  it should "generate valid SMTLib for HwachaSequencer" taggedAs (RequiresZ3) ignore {
+  it should "generate valid SMTLib for HwachaSequencer" taggedAs (RequiresZ3) in {
     compileAndParse("HwachaSequencer")
   }
   it should "generate valid SMTLib for ICache" taggedAs (RequiresZ3) in { compileAndParse("ICache") }
diff --git a/src/test/scala/firrtlTests/stage/FirrtlMainSpec.scala b/src/test/scala/firrtlTests/stage/FirrtlMainSpec.scala
index ea590d26..eaf48b49 100644
--- a/src/test/scala/firrtlTests/stage/FirrtlMainSpec.scala
+++ b/src/test/scala/firrtlTests/stage/FirrtlMainSpec.scala
@@ -164,16 +164,6 @@ class FirrtlMainSpec
          |""".stripMargin
   }
 
-  /** This returns a string containing the default standard out string based on the Scala version. E.g., if there are
-    * version-specific deprecation warnings, those are available here and can be passed to tests that should have them.
-    */
-  val defaultStdOut: Option[String] = BuildInfo.scalaVersion.split("\\.").toList match {
-    case "2" :: v :: _ :: Nil if v.toInt <= 11 =>
-      Some(CheckScalaVersion.deprecationMessage("2.11", s"--${WarnNoScalaVersionDeprecation.longOption}"))
-    case x =>
-      None
-  }
-
   info("As a FIRRTL command line user")
   info("I want to compile some FIRRTL")
   Feature("FirrtlMain command line interface") {
@@ -205,58 +195,48 @@ class FirrtlMainSpec
     Seq(
       /* Test all standard emitters with and without annotation file outputs */
       FirrtlMainTest(args = Array("-X", "none", "-E", "chirrtl"), files = Seq("Top.fir")),
-      FirrtlMainTest(args = Array("-X", "high", "-E", "high"), stdout = defaultStdOut, files = Seq("Top.hi.fir")),
+      FirrtlMainTest(args = Array("-X", "high", "-E", "high"), files = Seq("Top.hi.fir")),
       FirrtlMainTest(
         args = Array("-X", "middle", "-E", "middle", "-foaf", "Top"),
-        stdout = defaultStdOut,
         files = Seq("Top.mid.fir", "Top.anno.json")
       ),
       FirrtlMainTest(
         args = Array("-X", "low", "-E", "low", "-foaf", "annotations.anno.json"),
-        stdout = defaultStdOut,
         files = Seq("Top.lo.fir", "annotations.anno.json")
       ),
       FirrtlMainTest(
         args = Array("-X", "verilog", "-E", "verilog", "-foaf", "foo.anno"),
-        stdout = defaultStdOut,
         files = Seq("Top.v", "foo.anno.anno.json")
       ),
       FirrtlMainTest(
         args = Array("-X", "sverilog", "-E", "sverilog", "-foaf", "foo.json"),
-        stdout = defaultStdOut,
         files = Seq("Top.sv", "foo.json.anno.json")
       ),
       /* Test all one file per module emitters */
       FirrtlMainTest(args = Array("-X", "none", "-e", "chirrtl"), files = Seq("Top.fir", "Child.fir")),
       FirrtlMainTest(
         args = Array("-X", "high", "-e", "high"),
-        stdout = defaultStdOut,
         files = Seq("Top.hi.fir", "Child.hi.fir")
       ),
       FirrtlMainTest(
         args = Array("-X", "middle", "-e", "middle"),
-        stdout = defaultStdOut,
         files = Seq("Top.mid.fir", "Child.mid.fir")
       ),
       FirrtlMainTest(
         args = Array("-X", "low", "-e", "low"),
-        stdout = defaultStdOut,
         files = Seq("Top.lo.fir", "Child.lo.fir")
       ),
       FirrtlMainTest(
         args = Array("-X", "verilog", "-e", "verilog"),
-        stdout = defaultStdOut,
         files = Seq("Top.v", "Child.v")
       ),
       FirrtlMainTest(
         args = Array("-X", "sverilog", "-e", "sverilog"),
-        stdout = defaultStdOut,
         files = Seq("Top.sv", "Child.sv")
       ),
       /* Test mixing of -E with -e */
       FirrtlMainTest(
         args = Array("-X", "middle", "-E", "high", "-e", "middle"),
-        stdout = defaultStdOut,
         files = Seq("Top.hi.fir", "Top.mid.fir", "Child.mid.fir"),
         notFiles = Seq("Child.hi.fir")
       ),
@@ -264,33 +244,27 @@ class FirrtlMainSpec
       FirrtlMainTest(args = Array("-X", "none", "-E", "chirrtl", "-o", "foo"), files = Seq("foo.fir")),
       FirrtlMainTest(
         args = Array("-X", "high", "-E", "high", "-o", "foo"),
-        stdout = defaultStdOut,
         files = Seq("foo.hi.fir")
       ),
       FirrtlMainTest(
         args = Array("-X", "middle", "-E", "middle", "-o", "foo.middle"),
-        stdout = defaultStdOut,
         files = Seq("foo.middle.mid.fir")
       ),
       FirrtlMainTest(
         args = Array("-X", "low", "-E", "low", "-o", "foo.lo.fir"),
-        stdout = defaultStdOut,
         files = Seq("foo.lo.fir")
       ),
       FirrtlMainTest(
         args = Array("-X", "verilog", "-E", "verilog", "-o", "foo.sv"),
-        stdout = defaultStdOut,
         files = Seq("foo.sv.v")
       ),
       FirrtlMainTest(
         args = Array("-X", "sverilog", "-E", "sverilog", "-o", "Foo"),
-        stdout = defaultStdOut,
         files = Seq("Foo.sv")
       ),
       /* Test that an output is generated if no emitter is specified */
       FirrtlMainTest(
         args = Array("-X", "verilog", "-o", "Foo"),
-        stdout = defaultStdOut,
         files = Seq("Foo.v")
       )
     )