Merge pull request #3867 from lrytz/t8708

SI-8708 Fix pickling of LOCAL_CHILD child of sealed classes

1 files changed, 37 insertions, 5 deletions

diff --git a/src/reflect/scala/reflect/internal/pickling/UnPickler.scala b/src/reflect/scala/reflect/internal/pickling/UnPickler.scala
index 64a1a44722..b808666360 100644
--- a/src/reflect/scala/reflect/internal/pickling/UnPickler.scala
+++ b/src/reflect/scala/reflect/internal/pickling/UnPickler.scala
@@ -290,6 +290,25 @@ abstract class UnPickler {
       def pflags       = flags & PickledFlags
 
       def finishSym(sym: Symbol): Symbol = {
+        /**
+         * member symbols (symbols owned by a class) are added to the class's scope, with a number
+         * of exceptions:
+         *
+         * (.) ...
+         * (1) `local child` represents local child classes, see comment in Pickler.putSymbol.
+         *     Since it is not a member, it should not be entered in the owner's scope.
+         */
+        def shouldEnterInOwnerScope = {
+          sym.owner.isClass &&
+            sym != classRoot &&
+            sym != moduleRoot &&
+            !sym.isModuleClass &&
+            !sym.isRefinementClass &&
+            !sym.isTypeParameter &&
+            !sym.isExistentiallyBound &&
+            sym.rawname != tpnme.LOCAL_CHILD // (1)
+        }
+
         markFlagsCompleted(sym)(mask = AllFlags)
         sym.privateWithin = privateWithin
         sym.info = (
@@ -302,8 +321,7 @@ abstract class UnPickler {
             newLazyTypeRefAndAlias(inforef, readNat())
           }
         )
-        if (sym.owner.isClass && sym != classRoot && sym != moduleRoot &&
-            !sym.isModuleClass && !sym.isRefinementClass && !sym.isTypeParameter && !sym.isExistentiallyBound)
+        if (shouldEnterInOwnerScope)
           symScope(sym.owner) enter sym
 
         sym
@@ -681,10 +699,24 @@ abstract class UnPickler {
       private val p = phase
       protected def completeInternal(sym: Symbol) : Unit = try {
         val tp = at(i, () => readType(sym.isTerm)) // after NMT_TRANSITION, revert `() => readType(sym.isTerm)` to `readType`
-        if (p ne null)
-          slowButSafeEnteringPhase(p) (sym setInfo tp)
+
+        // This is a temporary fix allowing to read classes generated by an older, buggy pickler.
+        // See the generation of the LOCAL_CHILD class in Pickler.scala. In an earlier version, the
+        // pickler did not add the ObjectTpe superclass, it used a trait as the first parent. This
+        // tripped an assertion in AddInterfaces which checks that the first parent is not a trait.
+        // This workaround can probably be removed in 2.12, because the 2.12 compiler is supposed
+        // to only read classfiles generated by 2.12.
+        val fixLocalChildTp = if (sym.rawname == tpnme.LOCAL_CHILD) tp match {
+            case ClassInfoType(superClass :: traits, decls, typeSymbol) if superClass.typeSymbol.isTrait =>
+              ClassInfoType(definitions.ObjectTpe :: superClass :: traits, decls, typeSymbol)
+            case _ => tp
+          } else tp
+
+        if (p ne null) {
+          slowButSafeEnteringPhase(p)(sym setInfo fixLocalChildTp)
+        }
         if (currentRunId != definedAtRunId)
-          sym.setInfo(adaptToNewRunMap(tp))
+          sym.setInfo(adaptToNewRunMap(fixLocalChildTp))
       }
       catch {
         case e: MissingRequirementError => throw toTypeError(e)