Enable flat classpath by default

Implements VirtualDirectoryFlatClassPath, which is required for the
presentation compiler created for the repl's tab-completion.

Various minor cleanups in the flat classpath implementation.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/compiler/scala/tools/nsc/classpath/ZipArchiveFileLookup.scala b/src/compiler/scala/tools/nsc/classpath/ZipArchiveFileLookup.scala
index 1d0de57779..a24d989306 100644
--- a/src/compiler/scala/tools/nsc/classpath/ZipArchiveFileLookup.scala
+++ b/src/compiler/scala/tools/nsc/classpath/ZipArchiveFileLookup.scala
@@ -57,7 +57,7 @@ trait ZipArchiveFileLookup[FileEntryType <: ClassRepClassPathEntry] extends Flat
     } getOrElse FlatClassPathEntries(Seq.empty, Seq.empty)
   }
 
-  private def findDirEntry(pkg: String) = {
+  private def findDirEntry(pkg: String): Option[archive.DirEntry] = {
     val dirName = s"${FileUtils.dirPath(pkg)}/"
     archive.allDirs.get(dirName)
   }