Take phase control settings into account

Run now interprets correctly

     -YstopBefore
     -YstopAfter
     -Yskip
     -Tprint

phase settings. For now, we stop by default before
erasure, until erasure is fully debugged.

Author: odersky

src/dotty/tools/dotc/Compiler.scala

@@ -22,7 +22,7 @@ class Compiler {
       List(new FrontEnd),
       List(new LazyValsCreateCompanionObjects),      //force separataion between lazyVals and LVCreateCO
       List(new LazyValTranformContext().transformer, new TypeTestsCasts),
-   //   List(new Erasure),
+      List(new Erasure),
       List(new UncurryTreeTransform)
     )
 

src/dotty/tools/dotc/Run.scala

@@ -2,7 +2,7 @@ package dotty.tools
 package dotc
 
 import core._
-import Contexts._, Periods._, Symbols._
+import Contexts._, Periods._, Symbols._, Phases._, Decorators._
 import io.PlainFile
 import util.{SourceFile, NoSource, Stats, SimpleMap}
 import reporting.Reporter
@@ -30,13 +30,29 @@ class Run(comp: Compiler)(implicit ctx: Context) {
   def compileSources(sources: List[SourceFile]) = Stats.monitorHeartBeat {
     if (sources forall (_.exists)) {
       units = sources map (new CompilationUnit(_))
-      for (phase <- ctx.allPhases.init) {
-        if (!ctx.reporter.hasErrors)
+      def stoppedBefore(phase: Phase) =
+        ctx.settings.YstopBefore.value.containsPhase(phase) ||
+        ctx.settings.YstopAfter.value.containsPhase(phase.prev)
+      val phasesToRun = ctx.allPhases.init
+        .takeWhile(!stoppedBefore(_))
+        .filterNot(ctx.settings.Yskip.value.containsPhase(_))
+      for (phase <- phasesToRun) {
+        if (!ctx.reporter.hasErrors) {
           phase.runOn(units)
+          if (ctx.settings.Xprint.value.containsPhase(phase))
+            for (unit <- units)
+              printTree(ctx.fresh.withNewPhase(phase).withCompilationUnit(unit))
+        }
       }
     }
   }
 
+  private def printTree(implicit ctx: Context) = {
+    val unit = ctx.compilationUnit
+    println(s"result of $unit after ${ctx.phase}:")
+    println(unit.tpdTree.show)
+  }
+
   def compile(sourceCode: String): Unit = {
     val virtualFile = new VirtualFile(sourceCode) // use source code as name as it's used for equals
     val writer = new BufferedWriter(new OutputStreamWriter(virtualFile.output, "UTF-8")) // buffering is still advised by javadoc

src/dotty/tools/dotc/config/ScalaSettings.scala

@@ -125,12 +125,12 @@ class ScalaSettings extends Settings.SettingGroup {
   val XshowtreesStringified = BooleanSetting("-Yshow-trees-stringified", "(Requires -Xprint:) Print stringifications along with detailed ASTs.")
   val Yshowsyms = BooleanSetting("-Yshow-syms", "Print the AST symbol hierarchy after each phase.")
   val Yshowsymkinds = BooleanSetting("-Yshow-symkinds", "Print abbreviated symbol kinds next to symbol names.")
-  val skip = PhasesSetting("-Yskip", "Skip")
+  val Yskip = PhasesSetting("-Yskip", "Skip")
   val Ygenjavap = StringSetting("-Ygen-javap", "dir", "Generate a parallel output directory of .javap files.", "")
   val Ydumpclasses = StringSetting("-Ydump-classes", "dir", "Dump the generated bytecode to .class files (useful for reflective compilation that utilizes in-memory classloaders).", "")
   val Ynosqueeze = BooleanSetting("-Yno-squeeze", "Disable creation of compact code in matching.")
-  val stopAfter = PhasesSetting("-Ystop-after", "Stop after") withAbbreviation ("-stop") // backward compat
-  val stopBefore = PhasesSetting("-Ystop-before", "Stop before")
+  val YstopAfter = PhasesSetting("-Ystop-after", "Stop after") withAbbreviation ("-stop") // backward compat
+  val YstopBefore = PhasesSetting("-Ystop-before", "Stop before", "erasure") // stop before erasure as long as we have not debugged it fully
   val refinementMethodDispatch = ChoiceSetting("-Ystruct-dispatch", "policy", "structural method dispatch policy", List("no-cache", "mono-cache", "poly-cache", "invoke-dynamic"), "poly-cache")
   val Yrangepos = BooleanSetting("-Yrangepos", "Use range positions for syntax trees.")
   val Ybuilderdebug = ChoiceSetting("-Ybuilder-debug", "manager", "Compile using the specified build manager.", List("none", "refined", "simple"), "none")
@@ -144,7 +144,7 @@ class ScalaSettings extends Settings.SettingGroup {
   val YshowSuppressedErrors = BooleanSetting("-Yshow-suppressed-errors", "Also show follow-on errors and warnings that are normally supressed.")
   val Yheartbeat = BooleanSetting("-Yheartbeat", "show heartbeat stack trace of compiler operations.")
   val Yprintpos = BooleanSetting("-Yprintpos", "show tree positions")
-  def stop = stopAfter
+  def stop = YstopAfter
 
   /** Area-specific debug output.
    */