SI-6440 Address regressions around MissingRequirementError

 Go back to using globalError to report when a stub's info is referenced,
 and only throw the MissingRequirementError when compilation really
 must abort due to having a StubTermSymbol in a place where a
 StubClassSymbol would have been a better choice.

 This situation arises when an entire package is missing from the
 classpath, as was the case in the reported bug.

 Adds `StoreReporterDirectTest`, which buffers messages issued
 during compilation for more structured interrogation. Use this
 in two test for manifests -- these tests were using a crude means
 of grepping compiler console output to focus on the relevant output,
 but this approach was insufficient with the new multi-line error
 message emitted as part of this change.

 Also used that base test class to add two new tests: one for
 the reported error (package missing), and another for a simpler
 error (class missing). The latter test shows how stub symbols
 allow code to compile if it doesn't the subset of signatures
 in some type that refer to a missing class.

 Gave the INFO/WARNING/ERROR members of Reporter sensible
 toString implementations; they inherit from Enumeration#Value
 in an unusual manner (why?) that means the built in toString of
 Enumeration printed `Severity@0`.

2 files changed, 21 insertions, 2 deletions

diff --git a/src/partest/scala/tools/partest/DirectTest.scala b/src/partest/scala/tools/partest/DirectTest.scala
index 554e7848c7..8c18809ad6 100644
--- a/src/partest/scala/tools/partest/DirectTest.scala
+++ b/src/partest/scala/tools/partest/DirectTest.scala
@@ -8,6 +8,7 @@ package scala.tools.partest
 import scala.tools.nsc._
 import io.Directory
 import util.{BatchSourceFile, CommandLineParser}
+import reporters.{Reporter, ConsoleReporter}
 
 /** A class for testing code which is embedded as a string.
  *  It allows for more complete control over settings, compiler
@@ -38,9 +39,12 @@ abstract class DirectTest extends App {
   // new compiler
   def newCompiler(args: String*): Global = {
     val settings = newSettings((CommandLineParser tokenize ("-d \"" + testOutput.path + "\" " + extraSettings)) ++ args.toList)
-    if (settings.Yrangepos.value) new Global(settings) with interactive.RangePositions
-    else new Global(settings)
+    if (settings.Yrangepos.value) new Global(settings, reporter(settings)) with interactive.RangePositions
+    else new Global(settings, reporter(settings))
   }
+
+  def reporter(settings: Settings): Reporter = new ConsoleReporter(settings)
+
   def newSources(sourceCodes: String*) = sourceCodes.toList.zipWithIndex map {
     case (src, idx) => new BatchSourceFile("newSource" + (idx + 1), src)
   }
diff --git a/src/partest/scala/tools/partest/StoreReporterDirectTest.scala b/src/partest/scala/tools/partest/StoreReporterDirectTest.scala
new file mode 100644
index 0000000000..7f3604c86c
--- /dev/null
+++ b/src/partest/scala/tools/partest/StoreReporterDirectTest.scala
@@ -0,0 +1,15 @@
+package scala.tools.partest
+
+import scala.tools.nsc.Settings
+import scala.tools.nsc.reporters.StoreReporter
+import scala.collection.mutable
+
+trait StoreReporterDirectTest extends DirectTest {
+  lazy val storeReporter: StoreReporter = new scala.tools.nsc.reporters.StoreReporter()
+
+  /** Discards all but the first message issued at a given position. */
+  def filteredInfos: Seq[storeReporter.Info] = storeReporter.infos.groupBy(_.pos).map(_._2.head).toList
+
+  /** Hook into [[scala.tools.partest.DirectTest]] to install the custom reporter */
+  override def reporter(settings: Settings) = storeReporter
+}