7 files changed, 66 insertions, 12 deletions
diff --git a/src/compiler/scala/tools/nsc/typechecker/Namers.scala b/src/compiler/scala/tools/nsc/typechecker/Namers.scala
index 756863f8f9..5687917e46 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Namers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Namers.scala
@@ -360,7 +360,7 @@ trait Namers { self: Analyzer =>
             } exists (_.mods hasFlag DEFAULTPARAM)
 
             if (hasDefault) {
-              val m = ensureCompanionObject(tree, companionModuleDef(tree, List(gen.scalaScalaObjectConstr)))
+              val m = ensureCompanionObject(tree, companionModuleDef(tree))
               classAndNamerOfModule(m) = (tree, null)
             }
           case tree @ ModuleDef(mods, name, _) =>
diff --git a/src/compiler/scala/tools/nsc/typechecker/SyntheticMethods.scala b/src/compiler/scala/tools/nsc/typechecker/SyntheticMethods.scala
index eedf36c400..44930ffc81 100644
--- a/src/compiler/scala/tools/nsc/typechecker/SyntheticMethods.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/SyntheticMethods.scala
@@ -289,14 +289,17 @@ trait SyntheticMethods extends ast.TreeDSL {
           ts += impl()
       }
 
-      if (clazz.isModuleClass && hasSerializableAnnotation(clazz)) {
-        // If you serialize a singleton and then deserialize it twice,
-        // you will have two instances of your singleton, unless you implement
-        // the readResolve() method (see http://www.javaworld.com/javaworld/
-        // jw-04-2003/jw-0425-designpatterns_p.html)
-        // question: should we do this for all serializable singletons, or (as currently done)
-        // only for those that carry a @serializable annotation?
-        if (!hasImplementation(nme.readResolve)) ts += readResolveMethod
+      if (clazz.isModuleClass) {
+        if (!hasSerializableAnnotation(clazz))
+          clazz addAnnotation AnnotationInfo(SerializableAttr.tpe, Nil, Nil)
+
+        /** If you serialize a singleton and then deserialize it twice,
+         *  you will have two instances of your singleton, unless you implement
+         *  the readResolve() method (see http://www.javaworld.com/javaworld/
+         *  jw-04-2003/jw-0425-designpatterns_p.html)
+         */
+        if (!hasImplementation(nme.readResolve))
+          ts += readResolveMethod
       }
     } catch {
       case ex: TypeError =>
diff --git a/src/compiler/scala/tools/nsc/typechecker/Unapplies.scala b/src/compiler/scala/tools/nsc/typechecker/Unapplies.scala
index 735cb4a3c4..57540fffef 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Unapplies.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Unapplies.scala
@@ -147,14 +147,15 @@ trait Unapplies extends ast.TreeDSL
       TypeTree(),
       Literal(Constant(cdef.name.decode)))
 
-    companionModuleDef(cdef, parents ::: List(gen.scalaScalaObjectConstr), List(toString))
+    companionModuleDef(cdef, parents, List(toString))
   }
 
-  def companionModuleDef(cdef: ClassDef, parents: List[Tree], body: List[Tree] = Nil): ModuleDef = atPos(cdef.pos.focus) {
+  def companionModuleDef(cdef: ClassDef, parents: List[Tree] = Nil, body: List[Tree] = Nil): ModuleDef = atPos(cdef.pos.focus) {
+    val allParents = parents ::: List( gen.scalaScalaObjectConstr)
     ModuleDef(
       Modifiers(cdef.mods.flags & AccessFlags | SYNTHETIC, cdef.mods.privateWithin),
       cdef.name.toTermName,
-      Template(parents, emptyValDef, NoMods, Nil, List(Nil), body, cdef.impl.pos.focus))
+      Template(allParents, emptyValDef, NoMods, Nil, List(Nil), body, cdef.impl.pos.focus))
   }
 
   private val caseMods = Modifiers(SYNTHETIC | CASE)
diff --git a/test/files/run/t3667.check b/test/files/run/t3667.check
new file mode 100644
index 0000000000..01e79c32a8
--- /dev/null
+++ b/test/files/run/t3667.check
@@ -0,0 +1,3 @@
+1
+2
+3
diff --git a/test/files/run/t3667.scala b/test/files/run/t3667.scala
new file mode 100644
index 0000000000..804432c516
--- /dev/null
+++ b/test/files/run/t3667.scala
@@ -0,0 +1,45 @@
+object Test {
+  def main(args: Array[String]) {
+    val o1 = new Outer1
+    val o2 = new Outer2
+    val o3 = new Outer3
+
+    println(1)
+    ser(new o1.Inner(1))
+    o1.Inner // make sure the Inner$module field of the Outer1 instance is initialized!
+    ser(new o1.Inner(1))
+
+    println(2)
+    ser(new o2.Inner(1))
+    o2.Inner
+    ser(new o2.Inner(1))
+
+    println(3)
+    ser(new o3.Inner(1))
+    o3.Inner
+    ser(new o3.Inner(1))
+  }
+
+  def ser(o: AnyRef) {
+    val oos = new java.io.ObjectOutputStream(new java.io.ByteArrayOutputStream())
+    oos.writeObject(o)
+    oos.close()
+  }
+
+}
+
+@serializable
+class Outer1 {
+  @serializable
+  class Inner(x: Int = 1)
+}
+
+@serializable
+class Outer2 {
+  case class Inner(x: Int = 1)
+}
+
+@serializable
+class Outer3 {
+  case class Inner(x: Int)
+}
diff --git a/test/files/scalap/packageObject/result.test b/test/files/scalap/packageObject/result.test
index 6a8d6ae1d5..324992aae1 100644
--- a/test/files/scalap/packageObject/result.test
+++ b/test/files/scalap/packageObject/result.test
@@ -2,4 +2,5 @@ package object PackageObject extends java.lang.Object with scala.ScalaObject {
   def this() = { /* compiled code */ }
   type A = scala.Predef.String
   def foo(i : scala.Int) : scala.Int = { /* compiled code */ }
+  protected def readResolve() : java.lang.Object = { /* compiled code */ }
 }
diff --git a/test/files/scalap/traitObject/result.test b/test/files/scalap/traitObject/result.test
index 0d7de1535d..8978873fc7 100644
--- a/test/files/scalap/traitObject/result.test
+++ b/test/files/scalap/traitObject/result.test
@@ -5,4 +5,5 @@ trait TraitObject extends java.lang.Object with scala.ScalaObject {
 object TraitObject extends java.lang.Object with scala.ScalaObject {
   def this() = { /* compiled code */ }
   def bar : scala.Int = { /* compiled code */ }
+  protected def readResolve() : java.lang.Object = { /* compiled code */ }
 }