checkNoPrivateLeaks is now also done in TreeUnpickler

This could be abstracted better but we'll end up replacing
checkNoPrivateLeaks soon anyway due to #1723

Author: smarter

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

@@ -14,6 +14,7 @@ import scala.annotation.{tailrec, switch}
 import scala.collection.mutable.ListBuffer
 import scala.collection.{ mutable, immutable }
 import config.Printers.pickling
+import typer.Checking
 
 /** Unpickler for typed trees
  *  @param reader          the reader from which to unpickle
@@ -723,6 +724,12 @@ class TreeUnpickler(reader: TastyReader, tastyName: TastyName.Table, posUnpickle
         // no longer necessary.
       goto(end)
       setPos(start, tree)
+
+      // This is also done in PostTyper but needs to be redone here
+      if (!sym.is(SyntheticOrPrivate) && sym.owner.isClass) {
+        sym.info = Checking.checkNoPrivateLeaks(sym, tree.pos)
+      }
+      tree
     }
 
     private def readTemplate(implicit ctx: Context): Template = {

compiler/src/dotty/tools/dotc/transform/PostTyper.scala

@@ -107,6 +107,7 @@ class PostTyper extends MacroTransform with IdentityDenotTransformer  { thisTran
     private def transformMemberDef(tree: MemberDef)(implicit ctx: Context): Unit = {
       val sym = tree.symbol
       sym.transformAnnotations(transformAnnot)
+      // Has to be redone in TreeUnpickler
       if (!sym.is(SyntheticOrPrivate) && sym.owner.isClass) {
         val info1 = Checking.checkNoPrivateLeaks(sym, tree.pos)
         if (info1 ne sym.info)

tests/pickling/private-leak.scala

@@ -0,0 +1,9 @@
+package private_leak
+
+class Test {
+  private type Foo = Int
+
+  val x: Foo = 1
+
+  x // unpickled with type Foo
+}