escape FromJavaObject in TASTy, recover at unpickle

Author: bishabosha

compiler/src/dotty/tools/dotc/core/tasty/TreePickler.scala

@@ -13,7 +13,7 @@ import ast.{untpd, tpd}
 import Contexts.*, Symbols.*, Types.*, Names.*, Constants.*, Decorators.*, Annotations.*, Flags.*
 import Comments.{Comment, docCtx}
 import NameKinds.*
-import StdNames.nme
+import StdNames.{nme, tpnme}
 import config.Config
 import collection.mutable
 import reporting.{Profile, NoProfile}
@@ -49,6 +49,9 @@ class TreePickler(pickler: TastyPickler, attributes: Attributes) {
 
   private var profile: Profile = NoProfile
 
+  private val isOutlinePickle: Boolean = attributes.isOutline
+  private val isJavaPickle: Boolean = attributes.isJava
+
   def treeAnnots(tree: untpd.MemberDef): List[Tree] =
     val ts = annotTrees.lookup(tree)
     if ts == null then Nil else ts.toList
@@ -188,19 +191,19 @@ class TreePickler(pickler: TastyPickler, attributes: Attributes) {
       def pickleExternalRef(sym: Symbol) = {
         val isShadowedRef =
           sym.isClass && tpe.prefix.member(sym.name).symbol != sym
-        if (sym.is(Flags.Private) || isShadowedRef) {
+        if sym.is(Flags.Private) || isShadowedRef then
           writeByte(if (tpe.isType) TYPEREFin else TERMREFin)
           withLength {
             pickleNameAndSig(sym.name, sym.signature, sym.targetName)
             pickleType(tpe.prefix)
             pickleType(sym.owner.typeRef)
           }
-        }
-        else {
+        else if isJavaPickle && sym == defn.FromJavaObjectSymbol then
+          pickleType(defn.ObjectType) // when unpickling Java TASTy, replace by <FromJavaObject>
+        else
           writeByte(if (tpe.isType) TYPEREF else TERMREF)
           pickleNameAndSig(sym.name, tpe.signature, sym.targetName)
-          pickleType(tpe.prefix)
-        }
+            pickleType(tpe.prefix)
       }
       if (sym.is(Flags.Package)) {
         writeByte(if (tpe.isType) TYPEREFpkg else TERMREFpkg)
@@ -342,7 +345,7 @@ class TreePickler(pickler: TastyPickler, attributes: Attributes) {
           case _: Template | _: Hole => pickleTree(tpt)
           case _ if tpt.isType => pickleTpt(tpt)
         }
-        if attributes.isOutline && sym.isTerm && attributes.isJava then
+        if isOutlinePickle && sym.isTerm && isJavaPickle then
           // TODO: if we introduce outline typing for Scala definitions
           // then we will need to update the check here
           pickleElidedUnlessEmpty(rhs, tpt.tpe)

compiler/src/dotty/tools/dotc/core/tasty/TreeUnpickler.scala

@@ -441,7 +441,11 @@ class TreeUnpickler(reader: TastyReader,
           readPackageRef().termRef
         case TYPEREF =>
           val name = readName().toTypeName
-          TypeRef(readType(), name)
+          val pre = readType()
+          if unpicklingJava && name == tpnme.Object && (pre.termSymbol eq defn.JavaLangPackageVal) then
+            defn.FromJavaObjectType
+          else
+            TypeRef(pre, name)
         case TERMREF =>
           val sname = readName()
           val prefix = readType()
@@ -1202,12 +1206,11 @@ class TreeUnpickler(reader: TastyReader,
 
       def completeSelect(name: Name, sig: Signature, target: Name): Select =
         val qual = readTree()
-        val denot0 = accessibleDenot(qual.tpe.widenIfUnstable, name, sig, target)
         val denot =
-          if unpicklingJava && name == tpnme.Object && denot0.symbol == defn.ObjectClass then
-            defn.FromJavaObjectType.denot
+          if unpicklingJava && name == tpnme.Object && qual.symbol == defn.JavaLangPackageVal then
+            defn.FromJavaObjectSymbol.denot
           else
-            denot0
+            accessibleDenot(qual.tpe.widenIfUnstable, name, sig, target)
         makeSelect(qual, name, denot)
 
       def readQualId(): (untpd.Ident, TypeRef) =