Pickle shadowed names

Shadowed names in types need to be pickled and treated on
unpickling.

We choose to make Shadowed a separate TastyName class, to avoid
the ad-hoc name-mangling in current dotc. When names are redone
Shadowed will also become a special class in the compiler proper.

7 files changed, 35 insertions, 8 deletions

diff --git a/src/dotty/tools/dotc/core/pickling/NameBuffer.scala b/src/dotty/tools/dotc/core/pickling/NameBuffer.scala
index 70d6b9ee1..c72df5563 100644
--- a/src/dotty/tools/dotc/core/pickling/NameBuffer.scala
+++ b/src/dotty/tools/dotc/core/pickling/NameBuffer.scala
@@ -5,7 +5,7 @@ package pickling
 
 import collection.mutable
 import Names.{Name, chrs}
-import Decorators._
+import Decorators._, NameOps._
 import TastyBuffer._
 import scala.io.Codec
 import TastyName._
@@ -23,7 +23,13 @@ class NameBuffer extends TastyBuffer(100000) {
       nameRefs(name) = ref
       ref
   }
-  def nameIndex(name: Name): NameRef = nameIndex(Simple(name.toTermName))
+  def nameIndex(name: Name): NameRef = {
+    val tname = 
+      if (name.isShadowedName) Shadowed(nameIndex(name.revertShadowed))
+      else Simple(name.toTermName)
+    nameIndex(tname)
+  }
+  
   def nameIndex(str: String): NameRef = nameIndex(str.toTermName)
   
   private def withLength(op: => Unit): Unit = {
@@ -63,6 +69,9 @@ class NameBuffer extends TastyBuffer(100000) {
     case DefaultGetter(method, paramNumber) =>
       writeByte(DEFAULTGETTER)
       withLength { writeNameRef(method); writeNat(paramNumber) }
+    case Shadowed(original) =>
+      writeByte(SHADOWED)
+      withLength { writeNameRef(original) }
   }
   
   override def assemble(): Unit = {
diff --git a/src/dotty/tools/dotc/core/pickling/PickleFormat.scala b/src/dotty/tools/dotc/core/pickling/PickleFormat.scala
index 3338c355e..68751f75f 100644
--- a/src/dotty/tools/dotc/core/pickling/PickleFormat.scala
+++ b/src/dotty/tools/dotc/core/pickling/PickleFormat.scala
@@ -36,6 +36,7 @@ Macro-format:
                   MODULECLASS    Length module_NameRef
                   SUPERACCESSOR  Length accessed_NameRef
                   DEFAULTGETTER  Length method_NameRef paramNumber_Nat
+                  SHADOWED       Length original_NameRef
                   MANGLED        Length mangle_NameRef name_NameRef
                   ...
 
@@ -220,6 +221,7 @@ object PickleFormat {
   final val MODULECLASS = 5
   final val SUPERACCESSOR = 6
   final val DEFAULTGETTER = 7
+  final val SHADOWED = 8
 
 // AST tags
 
diff --git a/src/dotty/tools/dotc/core/pickling/TastyName.scala b/src/dotty/tools/dotc/core/pickling/TastyName.scala
index 581a87901..8508d7ffa 100644
--- a/src/dotty/tools/dotc/core/pickling/TastyName.scala
+++ b/src/dotty/tools/dotc/core/pickling/TastyName.scala
@@ -19,6 +19,7 @@ object TastyName {
   case class ModuleClass(module: NameRef) extends TastyName
   case class SuperAccessor(accessed: NameRef) extends TastyName
   case class DefaultGetter(method: NameRef, num: Int) extends TastyName
+  case class Shadowed(original: NameRef) extends TastyName
   
   class Table extends (NameRef => TastyName) {
     private val names = new mutable.ArrayBuffer[TastyName]
diff --git a/src/dotty/tools/dotc/core/pickling/TastyUnpickler.scala b/src/dotty/tools/dotc/core/pickling/TastyUnpickler.scala
index b67244e3b..d90dd2e32 100644
--- a/src/dotty/tools/dotc/core/pickling/TastyUnpickler.scala
+++ b/src/dotty/tools/dotc/core/pickling/TastyUnpickler.scala
@@ -58,6 +58,8 @@ class TastyUnpickler(reader: TastyReader) {
         SuperAccessor(readNameRef())
       case DEFAULTGETTER =>
         DefaultGetter(readNameRef(), readNat())
+      case SHADOWED =>
+        Shadowed(readNameRef())
     }
     assert(currentAddr == end, s"bad name $result $start $currentAddr $end")
     result
diff --git a/src/dotty/tools/dotc/core/pickling/TreePickler.scala b/src/dotty/tools/dotc/core/pickling/TreePickler.scala
index 3004043d5..7ffcaec6e 100644
--- a/src/dotty/tools/dotc/core/pickling/TreePickler.scala
+++ b/src/dotty/tools/dotc/core/pickling/TreePickler.scala
@@ -6,7 +6,7 @@ package pickling
 import ast.Trees._
 import PickleFormat._
 import core._
-import Contexts._, Symbols._, Types._, Names._, Constants._, Decorators._, Annotations._, StdNames.tpnme
+import Contexts._, Symbols._, Types._, Names._, Constants._, Decorators._, Annotations._, StdNames.tpnme, NameOps._
 import collection.mutable
 import TastyBuffer._
 
@@ -296,9 +296,13 @@ class TreePickler(pickler: TastyPickler) {
         pickleType(tree.tpe)
       case Select(qual, name) => 
         writeByte(SELECT)
+        val realName = tree.tpe match {
+          case tp: NamedType if tp.name.isShadowedName => tp.name
+          case _ => name
+        }
         val sig = tree.tpe.signature
-        if (sig == Signature.NotAMethod) pickleName(name)
-        else pickleNameAndSig(name, sig)
+        if (sig == Signature.NotAMethod) pickleName(realName)
+        else pickleNameAndSig(realName, sig)
         pickleTree(qual)
       case Apply(fun, args) =>
         writeByte(APPLY)
diff --git a/src/dotty/tools/dotc/core/pickling/TreeUnpickler.scala b/src/dotty/tools/dotc/core/pickling/TreeUnpickler.scala
index 9e18a9a6c..d7d53c3a9 100644
--- a/src/dotty/tools/dotc/core/pickling/TreeUnpickler.scala
+++ b/src/dotty/tools/dotc/core/pickling/TreeUnpickler.scala
@@ -69,6 +69,7 @@ class TreeUnpickler(reader: TastyReader, tastyName: TastyName.Table) {
     case Simple(name) => name
     case Qualified(qual, name) => toTermName(qual) ++ "." ++ toTermName(name)
     case Signed(original, params, result) => toTermName(original)
+    case Shadowed(original) => toTermName(original).shadowedName
     case Expanded(original) => ???
     case ModuleClass(original) => toTermName(original).moduleClassName.toTermName
     case SuperAccessor(accessed) => ???
@@ -686,10 +687,17 @@ class TreeUnpickler(reader: TastyReader, tastyName: TastyName.Table) {
               if (name == nme.CONSTRUCTOR) ctx.fresh.addMode(Mode.InSuperCall) else ctx
             readTerm()(localCtx)
           }
+          def readRest(name: Name, sig: Signature) = {
+            val unshadowed = if (name.isShadowedName) name.revertShadowed else name
+            val sel = readQual(unshadowed).selectWithSig(unshadowed, sig)
+            if (unshadowed != name) sel.withType(sel.tpe.asInstanceOf[NamedType].shadowed)
+            else sel
+          }
           readNameSplitSig match {
-            case name: Name => readQual(name).selectWithSig(name, Signature.NotAMethod)
-            case (name: Name, sig: Signature) => readQual(name).selectWithSig(name, sig)
+            case name: Name => readRest(name, Signature.NotAMethod)
+            case (name: Name, sig: Signature) => readRest(name, sig)
           }
+          
         case NEW =>
           New(readTpt())
         case EMPTYTREE =>
diff --git a/tests/pos/pickleOK/templateParents.scala b/tests/pos/pickleOK/templateParents.scala
index 316d8c81c..153c4b4da 100644
--- a/tests/pos/pickleOK/templateParents.scala
+++ b/tests/pos/pickleOK/templateParents.scala
@@ -7,7 +7,8 @@ object templateParents {
   class F extends C[Boolean](true) {
     def foo = x
   }
-  new C("abc") with D
+  val cd = new C("abc") with D
+  cd.x
 
 }