Fully replace -Xfuture by -Xsource

Leave the now no-op command line option for now.

project/ScalaOptionParser.scala

@@ -82,7 +82,7 @@ object ScalaOptionParser {
   }
 
   // TODO retrieve this data programmatically, ala https://github.com/scala/scala-tool-support/blob/master/bash-completion/src/main/scala/BashCompletion.scala
-  private def booleanSettingNames = List("-X", "-Xcheckinit", "-Xdev", "-Xdisable-assertions", "-Xexperimental", "-Xfatal-warnings", "-Xfuture", "-Xlog-free-terms", "-Xlog-free-types", "-Xlog-implicit-conversions", "-Xlog-implicits", "-Xlog-reflective-calls",
+  private def booleanSettingNames = List("-X", "-Xcheckinit", "-Xdev", "-Xdisable-assertions", "-Xexperimental", "-Xfatal-warnings", "-Xlog-free-terms", "-Xlog-free-types", "-Xlog-implicit-conversions", "-Xlog-implicits", "-Xlog-reflective-calls",
     "-Xno-forwarders", "-Xno-patmat-analysis", "-Xno-uescape", "-Xnojline", "-Xprint-pos", "-Xprint-types", "-Xprompt", "-Xresident", "-Xshow-phases", "-Xverify", "-Y",
     "-Ybreak-cycles", "-Ydebug", "-Ycompact-trees", "-YdisableFlatCpCaching", "-Ydoc-debug",
     "-Yide-debug",

src/compiler/scala/tools/nsc/settings/ScalaSettings.scala

@@ -39,9 +39,6 @@ trait ScalaSettings extends AbsScalaSettings
    */
   protected def defaultClasspath = Option(System.getenv("CLASSPATH")).getOrElse(".")
 
-  /** Enabled under -Xfuture. */
-  protected def futureSettings = List[BooleanSetting]()
-
   /** If any of these settings is enabled, the compiler should print a message and exit.  */
   def infoSettings = List[Setting](version, help, Xhelp, Yhelp, showPlugins, showPhases, genPhaseGraph, printArgs)
 
@@ -461,7 +458,7 @@ trait ScalaSettings extends AbsScalaSettings
 
   /** Groups of Settings.
    */
-  val future        = BooleanSetting("-Xfuture", "Turn on future language features.") enablingIfNotSetByUser futureSettings
+  val future        = BooleanSetting("-Xfuture", "Deprecated. The future is now.").withDeprecationMessage("Use -Xsource instead.")
   val optimise      = BooleanSetting("-optimise", "Compiler flag for the optimizer in Scala 2.11")
     .withAbbreviation("-optimize")
     .withDeprecationMessage("In 2.12, -optimise enables -opt:l:inline -opt-inline-from:**. Check -opt:help for using the Scala 2.12 optimizer.")

src/manual/scala/man1/scalac.scala

@@ -205,9 +205,6 @@ object scalac extends Command {
         Definition(
           CmdOption("Xfull-lubs"),
           "Retain pre 2.10 behavior of less aggressive truncation of least upper bounds."),
-        Definition(
-          CmdOption("Xfuture"),
-          "Turn on future language features."),
         Definition(
           CmdOption("Xgenerate-phase-graph", Argument("file")),
           "Generate the phase graphs (outputs .dot files) to fileX.dot."),

test/files/neg/t7294.scala

@@ -1,5 +1,5 @@
 object Test {
-  // Treat TupleN as final under -Xfuture for the for the purposes
-  // of the "fruitless type test" warning.
+  // TupleN is final now, so we get a
+  // "fruitless type test" warning.
   (1, 2) match { case Seq() => 0; case _ => 1 }
 }

test/files/run/t1503.scala

@@ -5,7 +5,7 @@ object Whatever {
 object Test extends App {
   // this should make it abundantly clear Any is the best return type we can guarantee
   def matchWhatever(x: Any): Any = x match { case n @ Whatever => n }
-  // until 2.13, when left to its own devices, and not under -Xfuture, the return type used to be Whatever.type
+  // until 2.13 the return type used to be Whatever.type
   // now it is Any
   def matchWhateverCCE(x: Any) = x match { case n @ Whatever => n }
 

test/junit/scala/util/TryTest.scala

@@ -5,7 +5,7 @@ import org.junit.runners.JUnit4
 import org.junit.Test
 import org.junit.Assert._
 
-/* Test Try's withFilter method, which was added along with the -Xfuture fix for scala/bug#6455  */
+/* Test Try's withFilter method, which was added along with the fix for scala/bug#6455  */
 @RunWith(classOf[JUnit4])
 class TryTest {
   @Test
@@ -32,4 +32,4 @@ class TryTest {
     for (x <- util.Try(1) if x == 1) ok = x == 1
     assert(ok)
   }
-}
+}