[WIP] Upgrade backend for Java 9 support

This commit temporarily changes .gitmodules until
lampepfl/scala#24 is merged.

Author: smarter

.gitmodules

@@ -1,7 +1,7 @@
 [submodule "scala-backend"]
 	path = scala-backend
-	url = https://github.com/lampepfl/scala.git
-	branch = sharing-backend
+	url = https://github.com/dotty-staging/scala.git
+	branch = fix-java9-itf
 [submodule "scala2-library"]
 	path = scala2-library
 	url = https://github.com/lampepfl/scala.git

compiler/src/dotty/tools/dotc/config/Settings.scala

@@ -132,7 +132,7 @@ object Settings {
         case (BooleanTag, _) =>
           update(true, args)
         case (OptionTag, _) =>
-          update(Some(propertyClass.get.newInstance), args)
+          update(Some(propertyClass.get.getConstructor().newInstance()), args)
         case (ListTag, _) =>
           if (argRest.isEmpty) missingArg
           else update((argRest split ",").toList, args)

compiler/src/dotty/tools/dotc/plugins/Plugin.scala

@@ -177,7 +177,7 @@ object Plugin {
   /** Instantiate a plugin class, given the class and
    *  the compiler it is to be used in.
    */
-  def instantiate(clazz: AnyClass): Plugin = clazz.newInstance.asInstanceOf[Plugin]
+  def instantiate(clazz: AnyClass): Plugin = clazz.getConstructor().newInstance().asInstanceOf[Plugin]
 }
 
 class PluginLoadException(val path: String, message: String, cause: Exception) extends Exception(message, cause) {

compiler/src/dotty/tools/dotc/quoted/QuoteDriver.scala

@@ -36,7 +36,7 @@ class QuoteDriver extends Driver {
 
     val clazz = classLoader.loadClass(driver.outputClassName.toString)
     val method = clazz.getMethod("apply")
-    val instance = clazz.newInstance()
+    val instance = clazz.getConstructor().newInstance()
 
     method.invoke(instance).asInstanceOf[T]
   }

compiler/src/dotty/tools/dotc/transform/Splicer.scala

@@ -125,7 +125,7 @@ object Splicer {
       } else {
         // nested object in an object
         val clazz = loadClass(sym.fullNameSeparated(FlatName))
-        (clazz, clazz.newInstance().asInstanceOf[Object])
+        (clazz, clazz.getConstructor().newInstance().asInstanceOf[Object])
       }
     }