Another exciting development in the world of -Y...

Another exciting development in the world of -Y options which I and
three other people will use. Today's is -Yrich-exceptions. Use it like
so:

  SOURCEPATH=/path/to/src scalac -Yrich-exceptions a.scala

In the repl, -Yrich-exceptions will cause lastException to be bound to
an Exceptional instead of old rusty Throwable. That spins up new powers:

  scala> Nil.head
  [Nil.head] (List.scala:389)
  (access lastException for the full trace)
  scala> lastException.show
  /* The repl internal portion of the stack trace is elided. */
  [Nil.head]
   386:   override def isEmpty = true
   387:   override def head: Nothing =
   388:     throw new NoSuchElementException("head of empty list")
  *389:   override def tail: List[Nothing] =
   390:     throw new UnsupportedOperationException("tail of empty list")
   391:   // Removal of equals method here might lead to an infinite recursion similar to IntMap.equals.
   392:   override def equals(that: Any) = that match {

  [line0.<init>] (<console>:6)
  [line0.<clinit>] (<console>:-1)

Also try "lastException.showTable" but this is getting a little long for
more excerpt. No review.

1 files changed, 7 insertions, 1 deletions

diff --git a/src/compiler/scala/tools/nsc/Global.scala b/src/compiler/scala/tools/nsc/Global.scala
index 0f05a7fcce..d05eb26443 100644
--- a/src/compiler/scala/tools/nsc/Global.scala
+++ b/src/compiler/scala/tools/nsc/Global.scala
@@ -12,7 +12,7 @@ import compat.Platform.currentTime
 import scala.collection.{ mutable, immutable }
 import io.{ SourceReader, AbstractFile, Path }
 import reporters.{ Reporter, ConsoleReporter }
-import util.{ ClassPath, SourceFile, Statistics, BatchSourceFile, ScriptSourceFile, ShowPickled, returning }
+import util.{ Exceptional, ClassPath, SourceFile, Statistics, BatchSourceFile, ScriptSourceFile, ShowPickled, returning }
 import reflect.generic.{ PickleBuffer, PickleFormat }
 
 import symtab.{ Flags, SymbolTable, SymbolLoaders }
@@ -147,6 +147,11 @@ class Global(var settings: Settings, var reporter: Reporter) extends SymbolTable
   def logError(msg: String, t: Throwable): Unit = ()
   def log(msg: => AnyRef): Unit = if (opt.logPhase) inform("[log " + phase + "] " + msg)
 
+  def logThrowable(t: Throwable): Unit = error(throwableAsString(t))
+  def throwableAsString(t: Throwable): String =
+    if (opt.richExes) Exceptional(t).force().context()
+    else util.stringFromWriter(t printStackTrace _)
+
 // ------------ File interface -----------------------------------------
 
   private val reader: SourceReader = {
@@ -227,6 +232,7 @@ class Global(var settings: Settings, var reporter: Reporter) extends SymbolTable
     def logClasspath  = settings.Ylogcp.value
     def printLate     = settings.printLate.value
     def printStats    = settings.Ystatistics.value
+    def richExes      = settings.YrichExes.value
     def showTrees     = settings.Xshowtrees.value
     def target        = settings.target.value
     def typerDebug    = settings.Ytyperdebug.value