static forwarders & private[this] val in trait

object Properties extends PropertiesTrait

trait PropertiesTrait {
  // the protected member is not emitted as a static member of  -- it works when dropping the access modifier
  // somehow, the module class member is considered deferred in BForwardersGen
  protected val propFilename: String = /
}

// [log jvm] No forwarder for 'getter propFilename' from Properties to 'module class Properties': false || m.isDeferred == true || false || false

// the following method is missing compared to scalac
// public final class Properties {
//     public static String propFilename() {
//         return Properties$.MODULE$.propFilename();
//     }

trait Chars {
  private[this] val char2uescapeArray = Array[Char]('\', 'u', 0, 0, 0, 0)
}

object Chars extends Chars

// +++ w/reflect/scala/reflect/internal/Chars$.class
// -  private final [C scala83014char2uescapeArray

Author: adriaanm

src/compiler/scala/tools/nsc/transform/Fields.scala

@@ -52,10 +52,10 @@ abstract class Fields extends InfoTransform with ast.TreeDSL with TypingTransfor
     val pre = site.thisType
     @tailrec def loop (bcs: List[Symbol]): Boolean = {
 //      println(s"checking ${bcs.head} for member overriding $member (of ${member.owner})")
-      bcs.head != member.owner && (matchingAccessor(pre, member, bcs.head) != NoSymbol || loop(bcs.tail))
+      bcs.nonEmpty && bcs.head != member.owner && (matchingAccessor(pre, member, bcs.head) != NoSymbol || loop(bcs.tail))
     }
 
-    loop(site.info.baseClasses)
+    member.exists && loop(site.info.baseClasses)
   }
 
   class FieldMemoization(accessorOrField: Symbol, site: Symbol) {
@@ -120,21 +120,24 @@ abstract class Fields extends InfoTransform with ast.TreeDSL with TypingTransfor
         // strict, memoized accessors will receive an implementation in first real class to extend this trait
         decls.foreach {
           case accessor if accessor hasFlag ACCESSOR =>
+            // check flags before calling makeNotPrivate
+            val memoizedGetter = !(accessor hasFlag (DEFERRED | LAZY)) && fieldMemoizationIn(accessor, clazz).needsField
+            val finality = if (accessor hasFlag FINAL) FINAL_TRAIT_ACCESSOR else 0
+
             // only affects private symbols, with a destructive update of their name, also sets flags
             // required for private vals in traits
             accessor.makeNotPrivate(clazz)
 
-            if (!(accessor hasFlag (DEFERRED | LAZY)) && fieldMemoizationIn(accessor, clazz).needsField) {
-              // in a trait, a memoized accessor becomes deferred
-              // (it'll receive an implementation in the first real class to extend this trait)
+            // trait members cannot be final (but the synthesized ones should be)
+            // LOCAL no longer applies (already made not-private)
+            accessor resetFlag (FINAL | LOCAL)
 
+            // derive trait setter after calling makeNotPrivate (so that names are mangled consistently)
+            if (memoizedGetter) {
+              // a memoized accessor in a trait is made deferred now (mixins will deal with non-memoized getters like any other method)
               // can't mark getter as FINAL in trait, but remember for when we synthetisize the impl in the subclass to make it FINAL
-              val finality = if (accessor hasFlag FINAL) FINAL_TRAIT_ACCESSOR else 0
-              accessor setFlag (finality | lateFINAL | DEFERRED | SYNTHESIZE_IMPL_IN_SUBCLASS)
-
-              // trait members cannot be final (but the synthesized ones should be)
-              // LOCAL no longer applies (already made not-private)
-              accessor resetFlag (FINAL | LOCAL)
+              // (it'll receive an implementation in the first real class to extend this trait)
+              accessor setFlag (finality | DEFERRED | SYNTHESIZE_IMPL_IN_SUBCLASS)
 
               if ((accessor hasFlag STABLE) && accessor.isGetter) // TODO: isGetter is probably redundant?
                 newSetters += newTraitSetter(accessor, clazz)
@@ -151,6 +154,7 @@ abstract class Fields extends InfoTransform with ast.TreeDSL with TypingTransfor
         } else tp
 
       // mix in fields & accessors for all mixed in traits
+
       case tp@ClassInfoType(parents, oldDecls, clazz) if !clazz.isPackageClass =>
         val site = clazz.thisType
         // TODO (1): improve logic below, which is used to avoid mixing in anything that would result in an error in refchecks
@@ -265,6 +269,7 @@ abstract class Fields extends InfoTransform with ast.TreeDSL with TypingTransfor
             mixedInFieldAndAccessors foreach newDecls.enter
             newDecls
           }
+//        println(s"new decls: $newDecls")
 
         if (newDecls eq oldDecls) tp
         else ClassInfoType(parents, newDecls, clazz)
@@ -285,12 +290,13 @@ abstract class Fields extends InfoTransform with ast.TreeDSL with TypingTransfor
     def fieldsAndAccessors(templateSym: Symbol): List[ValOrDefDef] = {
       val clazz = templateSym.owner
       def fieldAccess(accessor: Symbol) = {
-        val field = accessor.accessed
-        assert(field.exists, s"No field for $accessor in $clazz")
+        val fieldName = accessor.localName
+        val field = clazz.info.decl(fieldName)
+        assert(field.exists, s"Field '$fieldName' not found in ${clazz.info.decls}")
         Select(This(clazz), field)
       }
 
-      val accessorsAndFieldsNeedingTrees = afterOwnPhase{ clazz.info }.decls.toList.filter(_ hasFlag NEEDS_TREES)
+      val accessorsAndFieldsNeedingTrees = clazz.info.decls.toList.filter(_ hasFlag NEEDS_TREES)
       accessorsAndFieldsNeedingTrees foreach (_ resetFlag NEEDS_TREES) // emitting the needed trees now
 
 //      println(s"accessorsAndFieldsNeedingTrees: $accessorsAndFieldsNeedingTrees")

src/compiler/scala/tools/nsc/typechecker/Namers.scala

@@ -120,7 +120,7 @@ trait Namers extends MethodSynthesis {
     def deriveAccessors(vd: ValDef) = vd.mods.isLazy || (owner.isClass && deriveAccessorsInClass(vd))
 
     private def deriveAccessorsInClass(vd: ValDef) =
-      !vd.mods.isPrivateLocal &&         // note, private[this] lazy vals do get accessors -- see outer disjunction of deriveAccessors
+      (!vd.mods.isPrivateLocal || owner.isTrait) && // note, private[this] lazy vals do get accessors -- see outer disjunction of deriveAccessors
       !(vd.name startsWith nme.OUTER) && // outer accessors are added later, in explicitouter
       !isEnumConstant(vd)                // enums can only occur in classes, so only check here
 

test/files/trait-defaults/fields.scala

@@ -1,3 +1,40 @@
+// test mixin of getters / setters, and implementing abstract
+// methods using @BeanProperty
+class C extends T with BeanF {
+  def foo() {
+    setF("doch!")
+    setG(true)
+    this.getF()
+  }
+}
+
+trait T {
+  @scala.beans.BeanProperty var f = "nei"
+  @scala.beans.BooleanBeanProperty var g = false
+}
+
+trait BeanF {
+  def getF(): String
+  def setF(n: String): Unit
+
+  def isG(): Boolean
+  def setG(nb: Boolean): Unit
+}
+
+/*
+    @scala.beans.BeanProperty private[this] var f: String = "nei";
+    <accessor> def f: String = T.this.f;
+    <accessor> def f_=(x$1: String): Unit = T.this.f = x$1;
+    def setF(x$1: String): Unit = T.this.f = x$1;
+    @scala.beans.BooleanBeanProperty private[this] var g: Boolean = false;
+    <accessor> def g: Boolean = T.this.g;
+    <accessor> def g_=(x$1: Boolean): Unit = T.this.g = x$1;
+    def setG(x$1: Boolean): Unit = T.this.g = x$1;
+    def getF(): String = T.this.f;
+    def isG(): Boolean = T.this.g
+*/
+
+
 trait T { final val bla: Int = 123 }
 class C extends T // bla should be final in C
 
@@ -135,29 +172,29 @@ class SUB extends IterableSplitter
 //   }
 // }
 
-// class Nest { val x = println(1)}
+class Nest { val x = println(1)}
 
-// package scala
-//
-// trait OneConcreteVal[T] {
-//   @deprecatedOverriding val x = 1 // : T = ???
-//   @volatile  var vy = "a"
-//   println(x)
-//   def foo = x
-// }
-//
+package scala
 
-// trait OneOtherConcreteVal[T] {
-//   var y: T = ???
-// }
-//
-// class C extends OneConcreteVal[Int] with OneOtherConcreteVal[String]
+trait OneConcreteVal[T] {
+  @deprecatedOverriding val x = 1 // : T = ???
+  @volatile  var vy = "a"
+  println(x)
+  def foo = x
+}
 
-// object T extends App {
-//   val c = new C
-//   println(c.x)
-//   println(c.y)
-// }
+
+trait OneOtherConcreteVal[T] {
+  var y: T = ???
+}
+
+class C extends OneConcreteVal[Int] with OneOtherConcreteVal[String]
+
+object T extends App {
+  val c = new C
+  println(c.x)
+  println(c.y)
+}
 /*
 old decls for trait trait OneOtherConcreteVal: Scope{
   def y(): Object;
@@ -204,64 +241,64 @@ new decls for class C: Scope{
 */
 
 
-// class Meh {
-//   final val x = 1
-//   def foo = x
-// }
-// class CE extends Empty
-//
-// trait T {
-//   val abs: String
-//   protected val protabs: String
-//   val pub = "public"
-//   protected val prot = "protected"
-//   private val privvy = "private"
-//   private[this] val privateThis = "private[this]"
-//   // TODO:
-//   // final val const = "const"
-//
-//   trait Nested { println(abs + privateThis) }
-//
-//   object NO {
-//     println(abs)
-//     println(pub)
-//     println(prot)
-//     println(protabs)
-//     println(privvy)
-//     println(privateThis)
-//   }
-//
-//   trait NT {
-//     println(abs)
-//     println(pub)
-//     println(prot)
-//     println(protabs)
-//     println(privvy)
-//     println(privateThis)
-//   }
-//
-//   class NC {
-//     println(abs)
-//     println(pub)
-//     println(prot)
-//     println(protabs)
-//     println(privvy)
-//     println(privateThis)
-//   }
-// }
-//
-// class C extends AnyRef with T {
-//   println("x")
-//   val abs = "abstract"
-//   println("y")
-//   val protabs = "abstract protected"
-//   final val const = "const"
-//   println("z")
-// }
-//
-// object Test extends C {
-//   def main(args: Array[String]): Unit = {
-//   NO
-//   new NT{}
-//   new NC
-// }}
+class Meh {
+  final val x = 1
+  def foo = x
+}
+class CE extends Empty
+
+trait T {
+  val abs: String
+  protected val protabs: String
+  val pub = "public"
+  protected val prot = "protected"
+  private val privvy = "private"
+  private[this] val privateThis = "private[this]"
+  // TODO:
+  // final val const = "const"
+
+  trait Nested { println(abs + privateThis) }
+
+  object NO {
+    println(abs)
+    println(pub)
+    println(prot)
+    println(protabs)
+    println(privvy)
+    println(privateThis)
+  }
+
+  trait NT {
+    println(abs)
+    println(pub)
+    println(prot)
+    println(protabs)
+    println(privvy)
+    println(privateThis)
+  }
+
+  class NC {
+    println(abs)
+    println(pub)
+    println(prot)
+    println(protabs)
+    println(privvy)
+    println(privateThis)
+  }
+}
+
+class C extends AnyRef with T {
+  println("x")
+  val abs = "abstract"
+  println("y")
+  val protabs = "abstract protected"
+  final val const = "const"
+  println("z")
+}
+
+object Test extends C {
+  def main(args: Array[String]): Unit = {
+  NO
+  new NT{}
+  new NC
+}}

test/files/trait-defaults/private_this.scala

@@ -0,0 +1,5 @@
+trait Chars {
+  private[this] val char2uescapeArray: String = ???
+}
+
+object Chars extends Chars