Fix protected setter generation

Author: odersky

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

@@ -218,7 +218,7 @@ class PostTyper extends MacroTransform with IdentityDenotTransformer { thisPhase
               super.transform(tree1)
           }
         case tree @ Assign(sel: Select, _) =>
-          superAcc.transformAssign(super.transform(tree))
+          super.transform(superAcc.transformAssign(tree))
         case Inlined(call, bindings, expansion) =>
           // Leave only a call trace consisting of
           //  - a reference to the top-level class from which the call was inlined,

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

@@ -271,7 +271,7 @@ class SuperAccessors(thisPhase: DenotTransformer) {
       val accPos = tree.pos.focus
       val protectedAccessor = clazz.info.decl(accName).symbol orElse {
         val newAcc = ctx.newSymbol(
-            clazz, accName, Artifact, accType, coord = accPos).enteredAfter(thisPhase)
+            clazz, accName, Artifact | Method, accType, coord = accPos).enteredAfter(thisPhase)
         val code = DefDef(newAcc, vrefss => {
           val (receiver :: value :: Nil) :: Nil = vrefss
           Assign(receiver.select(field), value).withPos(accPos)

tests/pos/i3638.scala

@@ -0,0 +1,12 @@
+package p {
+  package a {
+    class JavaInteraction(arr: Array[Char])
+        extends java.io.CharArrayReader(arr) {
+      class Inner {
+        {
+          count = count
+        }
+      }
+    }
+  }
+}