SI-8779 Enable inlining of code within a REPL session

The REPL has a long running instance of Global which outputs
classfiles by default to a VirtualDirectory. The inliner did not find
any of these class files when compiling calls to methods defined in
previous runs (ie, previous lines of input.)

This commit:

  - Adds a hook to augment the classpath that the optimizer searches,
    and uses this in the REPL to add the output directory
  - Fixes the implementation of `findClassFile` in VirtualDirectory,
    which doesn't seem to have been used in anger before. I've factored out
    some common code into a new method on `AbstractFile`.
  - Fixes a similar problem getSubDir reported by Li Haoyi
  - Adds missing unit test coverage.

This also fixes a bug in REPL autocompletion for types defined
in packages >= 2 level deep (with the `:paste -raw` command).
I've added a test for this case.

1 files changed, 3 insertions, 0 deletions

diff --git a/src/compiler/scala/tools/nsc/Global.scala b/src/compiler/scala/tools/nsc/Global.scala
index a7880c72d7..e58d2d3b43 100644
--- a/src/compiler/scala/tools/nsc/Global.scala
+++ b/src/compiler/scala/tools/nsc/Global.scala
@@ -95,6 +95,9 @@ class Global(var currentSettings: Settings, var reporter: Reporter)
 
   type ThisPlatform = JavaPlatform { val global: Global.this.type }
   lazy val platform: ThisPlatform  = new GlobalPlatform
+  /* A hook for the REPL to add a classpath entry containing products of previous runs to inliner's bytecode repository*/
+  // Fixes SI-8779
+  def optimizerClassPath(base: ClassPath): ClassPath = base
 
   def classPath: ClassPath = platform.classPath