Support overloaded lazy vals coming from Scala2 traits.

Author: DarkDimius

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

@@ -165,8 +165,11 @@ class Mixin extends MiniPhaseTransform with SymTransformer { thisTransform =>
           transformFollowing(
             DefDef(implementation(getter.asTerm), 
                if (isScala2x) {
-                 if (getter.is(Flags.Lazy)) // lazy vals need to have a rhs that will be the lazy initializer
-                   ref(mixin.implClass).select(getter.name).appliedTo(This(ctx.owner.asClass))
+                 if (getter.is(Flags.Lazy)) { // lazy vals need to have a rhs that will be the lazy initializer
+                   val reciever = ref(mixin.implClass)
+                   val sym = reciever.tpe.nonPrivateDecl(getter.name).suchThat(_.is(Lazy)).symbol // lazy val can be overloaded
+                   ref(mixin.implClass).select(sym).appliedTo(This(ctx.owner.asClass))
+                 }
                  else default
                } else initial)
           )