Rely on Trait flag to generate interfaces.

Author: DarkDimius

src/dotty/tools/backend/jvm/DottyBackendInterface.scala

@@ -416,7 +416,7 @@ class DottyBackendInterface()(implicit ctx: Context) extends BackendInterface{
     def isLabel: Boolean = sym is Flags.Label
     def hasPackageFlag: Boolean = sym is Flags.Package
     def isImplClass: Boolean = sym is Flags.ImplClass
-    def isInterface: Boolean = (sym is Flags.JavaInterface) || (sym is Flags.PureInterface)
+    def isInterface: Boolean = (sym is Flags.PureInterface) || (sym is Flags.Trait)
     def hasGetter: Boolean = false // used only for generaration of beaninfo todo: implement
     def isGetter: Boolean = toDenot(sym).isGetter
     def isSetter: Boolean = toDenot(sym).isSetter

src/dotty/tools/dotc/transform/Mixin.scala

@@ -73,12 +73,7 @@ class Mixin extends MiniPhaseTransform with SymTransformer { thisTransform =>
   override def transformSym(sym: SymDenotation)(implicit ctx: Context): SymDenotation =
     if (sym.is(Accessor, butNot = Deferred) && sym.owner.is(Trait))
       sym.copySymDenotation(initFlags = sym.flags | Deferred)
-    else if(sym.is(Trait, JavaDefined)) { // fixup scala2 traits to become interfaces
-      val info = sym.asClass.classInfo
-      val parents: List[TypeRef] = defn.ObjectType.asInstanceOf[TypeRef] :: info.parents // new superClass is object
-      val newInfo = info.derivedClassInfo(classParents = parents)
-      sym.copySymDenotation(initFlags = sym.flags | JavaInterface, info = newInfo)
-    } else
+    else
       sym
 
   private def initializer(sym: Symbol)(implicit ctx: Context): TermSymbol = {