close #3951. review by dubochet.

4 files changed, 52 insertions, 3 deletions

diff --git a/src/compiler/scala/tools/nsc/symtab/Symbols.scala b/src/compiler/scala/tools/nsc/symtab/Symbols.scala
index e84ae10cee..e15328c6a1 100644
--- a/src/compiler/scala/tools/nsc/symtab/Symbols.scala
+++ b/src/compiler/scala/tools/nsc/symtab/Symbols.scala
@@ -63,7 +63,7 @@ trait Symbols extends reflect.generic.Symbols { self: SymbolTable =>
     private var rawannots: List[AnnotationInfoBase] = Nil
 
     /* Used in namer to check whether annotations were already assigned or not */
-    def rawAnnotations:List[AnnotationInfoBase] = rawannots
+    def rawAnnotations: List[AnnotationInfoBase] = rawannots
 
     /** After the typer phase (before, look at the definition's Modifiers), contains
      *  the annotations attached to member a definition (class, method, type, field).
diff --git a/src/library/scala/reflect/generic/UnPickler.scala b/src/library/scala/reflect/generic/UnPickler.scala
index ed103a3a43..d04b882f0d 100755
--- a/src/library/scala/reflect/generic/UnPickler.scala
+++ b/src/library/scala/reflect/generic/UnPickler.scala
@@ -65,14 +65,23 @@ abstract class UnPickler {
     //println("unpickled " + classRoot + ":" + classRoot.rawInfo + ", " + moduleRoot + ":" + moduleRoot.rawInfo);//debug
 
     def run() {
+      // read children last, fix for #3951
+      val queue = new collection.mutable.ListBuffer[() => Unit]()
+      def delay(i: Int, action: => Unit) {
+        queue += (() => at(i, {() => action; null}))
+      }
+
       for (i <- 0 until index.length) {
         if (isSymbolEntry(i))
           at(i, readSymbol)
         else if (isSymbolAnnotationEntry(i))
-          at(i, {() => readSymbolAnnotation(); null})
+          delay(i, readSymbolAnnotation())
         else if (isChildrenEntry(i))
-          at(i, {() => readChildren(); null})
+          delay(i, readChildren())
       }
+
+      for (action <- queue)
+        action()
     }
 
     private def checkVersion() {
diff --git a/test/files/pos/t3951/Coll_1.scala b/test/files/pos/t3951/Coll_1.scala
new file mode 100644
index 0000000000..c2cc39a1a9
--- /dev/null
+++ b/test/files/pos/t3951/Coll_1.scala
@@ -0,0 +1,36 @@
+trait Document {
+  sealed trait FieldBase
+  trait StaticFieldBase extends FieldBase with StaticDocument
+  trait DynamicFieldBase extends FieldBase with DynamicDocument
+}
+
+sealed trait StaticDocument extends Document {
+  abstract class AbstractField extends FieldBase
+}
+
+sealed trait DynamicDocument extends Document {
+  abstract class AbstractField extends FieldBase
+}
+
+class Coll extends StaticDocument
+
+// similiar issue with annotations
+class ann[T] extends StaticAnnotation
+
+trait StatDoc extends Doc {
+  @ann[StatFB]
+  def foo: Int
+}
+
+trait Doc {
+  @ann[DynDoc#ForceDynDoc]
+  def bar: Int
+  trait StatFB
+  trait DynFB
+}
+
+trait DynDoc extends Doc {
+  @ann[DynFB]
+  def baz: Int
+  trait ForceDynDoc
+}
diff --git a/test/files/pos/t3951/Test_2.scala b/test/files/pos/t3951/Test_2.scala
new file mode 100644
index 0000000000..2519543008
--- /dev/null
+++ b/test/files/pos/t3951/Test_2.scala
@@ -0,0 +1,4 @@
+object Test {
+  new Coll
+  trait T extends StatDoc
+}