Don't discard deprecation/unchecked warnings re...

Don't discard deprecation/unchecked warnings regardless of settings.

Changed warnings code to accumulate them rather than thoughtlessly
discarding them and issuing its well-known taunt. In the repl you can
take advantage of this with the :warnings command, which will show the
suppressed warnings from the last line which had any. Be advised that at
the moment it has some issues: unchecked warnings aren't making it out,
and near repl startup neither are deprecation warnings, so don't open a
bunch of tickets please.

References SI-4594, no review.

5 files changed, 94 insertions, 21 deletions

diff --git a/src/compiler/scala/tools/nsc/CompilationUnits.scala b/src/compiler/scala/tools/nsc/CompilationUnits.scala
index f5e32fbb09..470207fd35 100644
--- a/src/compiler/scala/tools/nsc/CompilationUnits.scala
+++ b/src/compiler/scala/tools/nsc/CompilationUnits.scala
@@ -83,11 +83,11 @@ trait CompilationUnits { self: Global =>
 
     def deprecationWarning(pos: Position, msg: String) =
       if (opt.deprecation) warning(pos, msg)
-      else currentRun.deprecationWarnings += 1
+      else currentRun.deprecationWarnings ::= ((pos, msg))
 
     def uncheckedWarning(pos: Position, msg: String) =
       if (opt.unchecked) warning(pos, msg)
-      else currentRun.uncheckedWarnings += 1
+      else currentRun.uncheckedWarnings ::= ((pos, msg))
 
     def incompleteInputError(pos: Position, msg:String) =
       reporter.incompleteInputError(pos, msg)
diff --git a/src/compiler/scala/tools/nsc/Global.scala b/src/compiler/scala/tools/nsc/Global.scala
index 83f4ce438f..57b5ed45ea 100644
--- a/src/compiler/scala/tools/nsc/Global.scala
+++ b/src/compiler/scala/tools/nsc/Global.scala
@@ -772,8 +772,8 @@ class Global(var currentSettings: Settings, var reporter: Reporter) extends Symb
     var currentUnit: CompilationUnit = _
 
     /** Counts for certain classes of warnings during this run. */
-    var deprecationWarnings: Int = 0
-    var uncheckedWarnings: Int = 0
+    var deprecationWarnings: List[(Position, String)] = Nil
+    var uncheckedWarnings: List[(Position, String)] = Nil
 
     /** Progress tracking.  Measured in "progress units" which are 1 per
      *  compilation unit per phase completed.
@@ -954,8 +954,8 @@ class Global(var currentSettings: Settings, var reporter: Reporter) extends Symb
           if (option.isDefault && count > 0)
             warning("there were %d %s warnings; re-run with %s for details".format(count, what, option.name))
         )
-        warn(deprecationWarnings, "deprecation", settings.deprecation)
-        warn(uncheckedWarnings, "unchecked", settings.unchecked)
+        warn(deprecationWarnings.size, "deprecation", settings.deprecation)
+        warn(uncheckedWarnings.size, "unchecked", settings.unchecked)
         // todo: migrationWarnings
       }
     }
diff --git a/src/compiler/scala/tools/nsc/interpreter/ILoop.scala b/src/compiler/scala/tools/nsc/interpreter/ILoop.scala
index 2ff8bb343f..457a34f9dc 100644
--- a/src/compiler/scala/tools/nsc/interpreter/ILoop.scala
+++ b/src/compiler/scala/tools/nsc/interpreter/ILoop.scala
@@ -225,7 +225,8 @@ class ILoop(in0: Option[BufferedReader], protected val out: JPrintWriter)
     nullary("replay", "reset execution and replay all previous commands", replay),
     shCommand,
     nullary("silent", "disable/enable automatic printing of results", verbosity),
-    cmd("type", "<expr>", "display the type of an expression without evaluating it", typeCommand)
+    cmd("type", "<expr>", "display the type of an expression without evaluating it", typeCommand),
+    nullary("warnings", "show the suppressed warnings from the most recent line which had any", warningsCommand)
   )
 
   /** Power user commands */
@@ -393,6 +394,9 @@ class ILoop(in0: Option[BufferedReader], protected val out: JPrintWriter)
       case _        => "" // the error message was already printed
     }
   }
+  private def warningsCommand(): Result = {
+    intp.lastWarnings foreach { case (pos, msg) => intp.reporter.warning(pos, msg) }
+  }
 
   private def javapCommand(line: String): Result = {
     if (javap == null)
diff --git a/src/compiler/scala/tools/nsc/interpreter/ILoopInit.scala b/src/compiler/scala/tools/nsc/interpreter/ILoopInit.scala
index d711428d22..a9c092861f 100644
--- a/src/compiler/scala/tools/nsc/interpreter/ILoopInit.scala
+++ b/src/compiler/scala/tools/nsc/interpreter/ILoopInit.scala
@@ -6,6 +6,7 @@
 package scala.tools.nsc
 package interpreter
 
+import util.Position
 import scala.tools.util.SignalManager
 import scala.util.control.Exception.ignoring
 
@@ -98,12 +99,19 @@ trait ILoopInit {
     if (!initIsComplete)
       withLock { while (!initIsComplete) initLoopCondition.await() }
   }
+  // private def warningsThunks = List(
+  //   () => intp.bind("lastWarnings", "" + manifest[List[(Position, String)]], intp.lastWarnings _),
+  // )
+
   protected def postInitThunks = List[Option[() => Unit]](
     Some(intp.setContextClassLoader _),
     if (isReplPower) Some(() => enablePowerMode(true)) else None,
     // do this last to avoid annoying uninterruptible startups
     Some(installSigIntHandler _)
   ).flatten
+  // ++ (
+  //   warningsThunks
+  // )
   // called once after init condition is signalled
   protected def postInitialization() {
     postInitThunks foreach (f => addThunk(f()))
diff --git a/src/compiler/scala/tools/nsc/interpreter/IMain.scala b/src/compiler/scala/tools/nsc/interpreter/IMain.scala
index 3abcb3e416..b516e137e8 100644
--- a/src/compiler/scala/tools/nsc/interpreter/IMain.scala
+++ b/src/compiler/scala/tools/nsc/interpreter/IMain.scala
@@ -60,9 +60,33 @@ import IMain._
  *  @author Moez A. Abdel-Gawad
  *  @author Lex Spoon
  */
-class IMain(val settings: Settings, protected val out: JPrintWriter) extends Imports {
+class IMain(initialSettings: Settings, protected val out: JPrintWriter) extends Imports {
   imain =>
 
+  private var currentSettings: Settings = initialSettings
+  def settings = currentSettings
+  def savingSettings[T](fn: Settings => Unit)(body: => T): T = {
+    val saved = currentSettings
+    currentSettings = saved.copy()
+    fn(currentSettings)
+    try body
+    finally currentSettings = saved
+  }
+  def mostRecentLine = prevRequestList match {
+    case Nil      => ""
+    case req :: _ => req.originalLine
+  }
+  def rerunWith(names: String*) = {
+    savingSettings((ss: Settings) => {
+      import ss._
+      names flatMap lookupSetting foreach {
+        case s: BooleanSetting => s.value = true
+        case _                 => ()
+      }
+    })(interpret(mostRecentLine))
+  }
+  def rerunForWarnings = rerunWith("-deprecation", "-unchecked", "-Xlint")
+
   /** construct an interpreter that reports to Console */
   def this(settings: Settings) = this(settings, new NewLinePrintWriter(new ConsoleWriter, true))
   def this() = this(new Settings())
@@ -408,14 +432,18 @@ class IMain(val settings: Settings, protected val out: JPrintWriter) extends Imp
     }
   }
 
+  def compileSourcesKeepingRun(sources: SourceFile*) = {
+    val run = new Run()
+    reporter.reset()
+    run compileSources sources.toList
+    (!reporter.hasErrors, run)
+  }
+
   /** Compile an nsc SourceFile.  Returns true if there are
    *  no compilation errors, or false otherwise.
    */
-  def compileSources(sources: SourceFile*): Boolean = {
-    reporter.reset()
-    new Run() compileSources sources.toList
-    !reporter.hasErrors
-  }
+  def compileSources(sources: SourceFile*): Boolean =
+    compileSourcesKeepingRun(sources: _*)._1
 
   /** Compile a string.  Returns true if there are no
    *  compilation errors, or false otherwise.
@@ -461,9 +489,11 @@ class IMain(val settings: Settings, protected val out: JPrintWriter) extends Imp
       case Some(trees)  => trees
     }
     repltrace(
-      trees map { t =>
-        t map { t0 => t0.getClass + " at " + safePos(t0, -1) + "\n" }
-      } mkString
+      trees map (t =>
+        t map (t0 =>
+          "  " + safePos(t0, -1) + ": " + t0.shortClass + "\n"
+        ) mkString ""
+      ) mkString "\n"
     )
     // If the last tree is a bare expression, pinpoint where it begins using the
     // AST node position and snap the line off there.  Rewrite the code embodied
@@ -747,6 +777,29 @@ class IMain(val settings: Settings, protected val out: JPrintWriter) extends Imp
         lineAfterTyper(sym.info member newTermName(name))
       }
     }
+    /** We get a bunch of repeated warnings for reasons I haven't
+     *  entirely figured out yet.  For now, squash.
+     */
+    private def removeDupWarnings(xs: List[(Position, String)]): List[(Position, String)] = {
+      if (xs.isEmpty)
+        return Nil
+
+      val ((pos, msg)) :: rest = xs
+      val filtered = rest filter { case (pos0, msg0) =>
+        (msg != msg0) || (pos.lineContent.trim != pos0.lineContent.trim) || {
+          // same messages and same line content after whitespace removal
+          // but we want to let through multiple warnings on the same line
+          // from the same run.  The untrimmed line will be the same since
+          // there's no whitespace indenting blowing it.
+          (pos.lineContent == pos0.lineContent)
+        }
+      }
+      ((pos, msg)) :: removeDupWarnings(filtered)
+    }
+    def lastWarnings: List[(Position, String)] = (
+      if (lastRun == null) Nil
+      else removeDupWarnings(lastRun.deprecationWarnings.reverse) ++ lastRun.uncheckedWarnings.reverse
+    )
     private var lastRun: Run = _
     private def evalMethod(name: String) = evalClass.getMethods filter (_.getName == name) match {
       case Array(method) => method
@@ -754,10 +807,9 @@ class IMain(val settings: Settings, protected val out: JPrintWriter) extends Imp
     }
     private def compileAndSaveRun(label: String, code: String) = {
       showCodeIfDebugging(code)
-      reporter.reset()
-      lastRun = new Run()
-      lastRun.compileSources(List(new BatchSourceFile(label, packaged(code))))
-      !reporter.hasErrors
+      val (success, run) = compileSourcesKeepingRun(new BatchSourceFile(label, packaged(code)))
+      lastRun = run
+      success
     }
   }
 
@@ -880,7 +932,9 @@ class IMain(val settings: Settings, protected val out: JPrintWriter) extends Imp
 
         // compile the result-extraction object
         beSilentDuring {
-          lineRep compile ResultObjectSourceCode(handlers)
+          savingSettings(_.nowarn.value = true) {
+            lineRep compile ResultObjectSourceCode(handlers)
+          }
         }
       }
     }
@@ -949,6 +1003,13 @@ class IMain(val settings: Settings, protected val out: JPrintWriter) extends Imp
       case _                        => naming.mostRecentVar
     })
 
+  def lastWarnings: List[(global.Position, String)] = (
+    prevRequests.reverseIterator
+       map (_.lineRep.lastWarnings)
+      find (_.nonEmpty)
+      getOrElse Nil
+  )
+
   def requestForName(name: Name): Option[Request] = {
     assert(definedNameMap != null, "definedNameMap is null")
     definedNameMap get name