Address reviewer comments on scala#416

Author: DarkDimius

src/dotty/tools/dotc/CompilationUnit.scala

@@ -17,10 +17,25 @@ class CompilationUnit(val source: SourceFile) {
   var tpdTree: tpd.Tree = tpd.EmptyTree
 
   def isJava = source.file.name.endsWith(".java")
-  
-  lazy val pickled: TastyPickler = new TastyPickler()
 
+  /**
+   * Pickler used to create TASTY sections.
+   * Sections: Header, ASTs and Positions are populated by `pickler` phase.
+   * Subsequent phases can add new sections.
+   */
+  lazy val pickler: TastyPickler = new TastyPickler()
+
+  /**
+   * Addresses in TASTY file of trees, stored by pickling.
+   * Note that trees are checked for reference equality,
+   * so one can reliably use this function only dirrectly after `pickler`
+   */
   var addrOfTree: tpd.Tree => Option[Addr] = (_ => None)
 
+  /**
+   * Addresses in TASTY file of symbols, stored by pickling.
+   * Note that trees are checked for reference equality,
+   * so one can reliably use this function only dirrectly after `pickler`
+   */
   var addrOfSym: Symbol => Option[Addr] = (_ => None)
 }

src/dotty/tools/dotc/transform/Pickler.scala

@@ -32,7 +32,7 @@ class Pickler extends Phase {
       pickling.println(i"unpickling in run ${ctx.runId}")
       if (ctx.settings.YtestPickler.value) beforePickling(unit) = tree.show
 
-      val pickler = unit.pickled
+      val pickler = unit.pickler
       val treePkl = new TreePickler(pickler)
       treePkl.pickle(tree :: Nil)
       unit.addrOfTree = treePkl.buf.addrOfTree
@@ -41,7 +41,7 @@ class Pickler extends Phase {
         new PositionPickler(pickler, treePkl.buf.addrOfTree).picklePositions(tree :: Nil, tree.pos)
 
       def rawBytes = // not needed right now, but useful to print raw format.
-        unit.pickled.assembleParts().iterator.grouped(10).toList.zipWithIndex.map {
+        unit.pickler.assembleParts().iterator.grouped(10).toList.zipWithIndex.map {
           case (row, i) => s"${i}0: ${row.mkString(" ")}"
         }
       // println(i"rawBytes = \n$rawBytes%\n%") // DEBUG
@@ -61,7 +61,7 @@ class Pickler extends Phase {
     ctx.definitions.init
     val unpicklers = 
       for (unit <- units) yield {
-        val unpickler = new DottyUnpickler(unit.pickled.assembleParts())
+        val unpickler = new DottyUnpickler(unit.pickler.assembleParts())
         unpickler.enter(roots = Set())
         unpickler
       }