Don't set the classpath if source starts with @

Because it means that it will be that all compiler arguments will be
expanded by the compiler, and setting the classpath in the benchmark
driver makes the empty classpath have precedence over the one in the
compiler args file.

Fixes #58.

Author: jvican

compilation/src/main/scalac/scala/tools/benchmark/BenchmarkDriver.scala

@@ -23,14 +23,17 @@ trait BenchmarkDriver extends BaseBenchmarkDriver {
 
 
     override protected def processSettingsHook(): Boolean = {
-      if (source == "scala")
-        settings.sourcepath.value = Paths.get(s"../corpus/$source/$corpusVersion/library").toAbsolutePath.normalize.toString
-      else
-        settings.classpath.value = findScalaJars
+      if (!source.startsWith("@")) {
+        // Don't set the classpath manually if it's to be loaded by the `@` processor
+        if (source == "scala")
+          settings.sourcepath.value = Paths.get(s"../corpus/$source/$corpusVersion/library").toAbsolutePath.normalize.toString
+        else settings.classpath.value = findScalaJars
+        if (depsClasspath != null && depsClasspath.nonEmpty)
+          settings.processArgumentString(s"-cp $depsClasspath")
+      }
+
       settings.outdir.value = tempDir.getAbsolutePath
       settings.nowarn.value = true
-      if (depsClasspath != null)
-        settings.processArgumentString(s"-cp $depsClasspath")
       true
     }
   }