Several fixes and refactorings for typechecking

1) Refactoring of package loaders that ensures that a package is always loaded before new members are entered. This led to a refactoring of sourceModule in completers into its own trait

2) Refactoring of optSelfType ot selfInfo. Class Infos may now have a reference to a symbol in their selfInfo field, instead of always a type, as it was before. This allows to introduce laziness for self type evaluation. Laziness is needed so that modules can be desugared and the desugared version be compiled without special tricks.

3) <init> and $init members are no longer inherited.

4) Refactoring of createSymbol and enterSym, so that creating symbols and entering them in a scope is decoupled.
    Renamed the driver operation form `enterSym(s)` to `index`.

1 files changed, 5 insertions, 3 deletions

diff --git a/src/dotty/tools/dotc/core/SymbolLoaders.scala b/src/dotty/tools/dotc/core/SymbolLoaders.scala
index dc65b77f4..2fbe147c7 100644
--- a/src/dotty/tools/dotc/core/SymbolLoaders.scala
+++ b/src/dotty/tools/dotc/core/SymbolLoaders.scala
@@ -142,13 +142,15 @@ class SymbolLoaders {
   /** Load contents of a package
    */
   class PackageLoader(override val sourceModule: TermSymbol, classpath: ClassPath)(implicit val cctx: CondensedContext)
-      extends ClassCompleterWithDecls(newScope) with SymbolLoader { // !!! TODO: ClassCompleter needed?
+      extends SymbolLoader with ModuleClassCompleter {
     def description = "package loader " + classpath.name
 
+    private[core] val preDecls: MutableScope = newScope
+
     def doComplete(root: SymDenotation) {
       assert(root is PackageClass, root)
       val pre = root.owner.thisType
-      root.info = ClassInfo(pre, root.symbol.asClass, Nil, root.decls, TermRef.withSym(pre, sourceModule))
+      root.info = ClassInfo(pre, root.symbol.asClass, Nil, preDecls, TermRef.withSym(pre, sourceModule))
       if (!sourceModule.isCompleted)
         sourceModule.completer.complete(sourceModule)
       if (!root.isRoot) {
@@ -205,7 +207,7 @@ class SymbolLoaders {
 /** A lazy type that completes itself by calling parameter doComplete.
  *  Any linked modules/classes or module classes are also initialized.
  */
-trait SymbolLoader extends LazyType {
+abstract class SymbolLoader extends LazyType {
   implicit val cctx: CondensedContext
 
   /** Load source or class file for `root`, return */