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, 13 insertions, 0 deletions

diff --git a/src/repl/scala/tools/nsc/interpreter/ReplGlobal.scala b/src/repl/scala/tools/nsc/interpreter/ReplGlobal.scala
index cf055e0758..0bb9eb6a0b 100644
--- a/src/repl/scala/tools/nsc/interpreter/ReplGlobal.scala
+++ b/src/repl/scala/tools/nsc/interpreter/ReplGlobal.scala
@@ -6,6 +6,9 @@
 package scala.tools.nsc
 package interpreter
 
+import scala.tools.nsc.backend.JavaPlatform
+import scala.tools.nsc.classpath.{AggregateClassPath, ClassPathFactory}
+import scala.tools.nsc.util.ClassPath
 import typechecker.Analyzer
 
 /** A layer on top of Global so I can guarantee some extra
@@ -31,4 +34,14 @@ trait ReplGlobal extends Global {
       new util.AbstractFileClassLoader(virtualDirectory, loader) {}
     }
   }
+
+  override def optimizerClassPath(base: ClassPath): ClassPath = {
+    settings.outputDirs.getSingleOutput match {
+      case None => base
+      case Some(out) =>
+        // Make bytecode of previous lines available to the inliner
+        val replOutClasspath = ClassPathFactory.newClassPath(settings.outputDirs.getSingleOutput.get, settings)
+        AggregateClassPath.createAggregate(platform.classPath, replOutClasspath)
+    }
+  }
 }