Address review comments

Change scheme how sourcenames are computed from filenames to account for filenames
that have additional `.`s in them. Fix comments.

Author: odersky

compiler/src/dotty/tools/dotc/ast/Desugar.scala

@@ -1022,8 +1022,8 @@ object desugar {
     else Apply(ref(tupleTypeRef.classSymbol.companionModule.termRef), ts)
   }
 
-  /** Group all definitions that can't be at the toplebel in
-   *  an object named `<source>#object` where `<source>` is the name of the source file.
+  /** Group all definitions that can't be at the toplevel in
+   *  an object named `<source>$package` where `<source>` is the name of the source file.
    *  Definitions that can't be at the toplevel are:
    *
    *   - all pattern, value and method definitions
@@ -1045,7 +1045,10 @@ object desugar {
     val (nestedStats, topStats) = pdef.stats.partition(needsObject)
     if (nestedStats.isEmpty) pdef
     else {
-      val sourceName = ctx.source.file.name.takeWhile(_ != '.')
+      var fileName = ctx.source.file.name
+      val end = fileName.lastIndexOf('.') // drop extension
+      val start = fileName.lastIndexOf('.', end - 1) // drop any prefix before another `.`
+      val sourceName = fileName.substring(start + 1, end)
       val groupName = (sourceName ++ str.TOPLEVEL_SUFFIX).toTermName
       val grouped = ModuleDef(groupName, Template(emptyConstructor, Nil, Nil, EmptyValDef, nestedStats))
       cpy.PackageDef(pdef)(pdef.pid, topStats :+ grouped)

compiler/src/dotty/tools/dotc/core/SymDenotations.scala

@@ -1974,8 +1974,8 @@ object SymDenotations {
      *  is as follows:
      *
      *  If this is the scala package look in the package first, and if nothing is found
-     *  there, look in the package object second. Otherwise, look in the package object
-     *  first, and if nothing is found there, in the package second.
+     *  there, look in the package object second. Otherwise, look in the both the package object
+     *  and the package and form a union of the results.
      *
      *  The reason for the special treatment of the scala package is that if we
      *  complete it too early, we freeze its superclass Any, so that no members can

compiler/src/dotty/tools/dotc/typer/Typer.scala

@@ -269,7 +269,7 @@ class Typer extends Namer
               !curOwner.isPackageObject
               // Package objects are never searched directly. We wait until we
               // hit the enclosing package. That way we make sure we consider
-              // all overloaded altrenatives of a definition, even if they are
+              // all overloaded alternatives of a definition, even if they are
               // in different source files.
 
           if (isNewDefScope) {