Avoid setupMethod in Driver

Driver should not know that patch functionality exists. Instead, introduce settings
that can introduce their own stateful values.

2 files changed, 12 insertions, 3 deletions

diff --git a/src/dotty/tools/dotc/config/ScalaSettings.scala b/src/dotty/tools/dotc/config/ScalaSettings.scala
index 17da1f8d1..cdbf6ec50 100644
--- a/src/dotty/tools/dotc/config/ScalaSettings.scala
+++ b/src/dotty/tools/dotc/config/ScalaSettings.scala
@@ -1,6 +1,8 @@
-package dotty.tools.dotc.config
+package dotty.tools.dotc
+package config
 
 import PathResolver.Defaults
+import rewrite.Patches
 
 class ScalaSettings extends Settings.SettingGroup {
 
@@ -48,7 +50,7 @@ class ScalaSettings extends Settings.SettingGroup {
   val d = StringSetting("-d", "directory|jar", "destination for generated classfiles.", ".")
   val nospecialization = BooleanSetting("-no-specialization", "Ignore @specialize annotations.")
   val language = MultiStringSetting("-language", "feature", "Enable one or more language features.")
-  val rewrite = BooleanSetting("-rewrite", "When used in conjunction with -language:Scala2 rewrites sources to migrate to new syntax")
+  val rewrite = OptionSetting[Patches.PatchedFiles]("-rewrite", "When used in conjunction with -language:Scala2 rewrites sources to migrate to new syntax")
 
   /** -X "Advanced" settings
    */
diff --git a/src/dotty/tools/dotc/config/Settings.scala b/src/dotty/tools/dotc/config/Settings.scala
index 73bb056aa..eddeb83ab 100644
--- a/src/dotty/tools/dotc/config/Settings.scala
+++ b/src/dotty/tools/dotc/config/Settings.scala
@@ -19,6 +19,7 @@ object Settings {
   val StringTag = ClassTag(classOf[String])
   val ListTag = ClassTag(classOf[List[_]])
   val VersionTag = ClassTag(classOf[ScalaVersion])
+  val OptionTag = ClassTag(classOf[Option[_]])
 
   class SettingsState(initialValues: Seq[Any]) {
     private var values = ArrayBuffer(initialValues: _*)
@@ -55,7 +56,8 @@ object Settings {
     choices: Seq[T] = Nil,
     prefix: String = "",
     aliases: List[String] = Nil,
-    depends: List[(Setting[_], Any)] = Nil)(private[Settings] val idx: Int) {
+    depends: List[(Setting[_], Any)] = Nil,
+    propertyClass: Option[Class[_]] = None)(private[Settings] val idx: Int) {
 
     def withAbbreviation(abbrv: String): Setting[T] =
       copy(aliases = aliases :+ abbrv)(idx)
@@ -112,6 +114,8 @@ object Settings {
       def doSet(argRest: String) = ((implicitly[ClassTag[T]], args): @unchecked) match {
         case (BooleanTag, _) =>
           update(true, args)
+        case (OptionTag, _) =>
+          update(Some(propertyClass.get.newInstance), args)
         case (ListTag, _) =>
           if (argRest.isEmpty) missingArg
           else update((argRest split ",").toList, args)
@@ -255,5 +259,8 @@ object Settings {
 
     def VersionSetting(name: String, descr: String, default: ScalaVersion = NoScalaVersion): Setting[ScalaVersion] =
       publish(Setting(name, descr, default))
+
+    def OptionSetting[T: ClassTag](name: String, descr: String): Setting[Option[T]] =
+      publish(Setting(name, descr, None, propertyClass = Some(implicitly[ClassTag[T]].runtimeClass)))
   }
 }