Fix crash reporter, units and phases (#17754)

Author: dwijnand

compiler/src/dotty/tools/dotc/Run.scala

@@ -308,7 +308,7 @@ class Run(comp: Compiler, ictx: Context) extends ImplicitRunInfo with Constraint
 
   private def printTree(last: PrintedTree)(using Context): PrintedTree = {
     val unit = ctx.compilationUnit
-    val fusedPhase = ctx.phase.prevMega
+    val fusedPhase = ctx.phase.prev.megaPhase
     val echoHeader = f"[[syntax trees at end of $fusedPhase%25s]] // ${unit.source}"
     val tree = if ctx.isAfterTyper then unit.tpdTree else unit.untpdTree
     val treeString = fusedPhase.show(tree)

compiler/src/dotty/tools/dotc/core/Phases.scala

@@ -321,10 +321,10 @@ object Phases {
     def run(using Context): Unit
 
     /** @pre `isRunnable` returns true */
-    def runOn(units: List[CompilationUnit])(using Context): List[CompilationUnit] =
+    def runOn(units: List[CompilationUnit])(using runCtx: Context): List[CompilationUnit] =
       units.map { unit =>
-        val unitCtx = ctx.fresh.setPhase(this.start).setCompilationUnit(unit).withRootImports
-        try run(using unitCtx)
+        given unitCtx: Context = runCtx.fresh.setPhase(this.start).setCompilationUnit(unit).withRootImports
+        try run
         catch case ex: Throwable if !ctx.run.enrichedErrorMessage =>
           println(ctx.run.enrichErrorMessage(s"unhandled exception while running $phaseName on $unit"))
           throw ex
@@ -425,8 +425,8 @@ object Phases {
     final def prev: Phase =
       if (id > FirstPhaseId) myBase.phases(start - 1) else NoPhase
 
-    final def prevMega(using Context): Phase =
-      ctx.base.fusedContaining(ctx.phase.prev)
+    final def megaPhase(using Context): Phase =
+      ctx.base.fusedContaining(this)
 
     final def next: Phase =
       if (hasNext) myBase.phases(end + 1) else NoPhase
@@ -439,8 +439,8 @@ object Phases {
     final def monitor(doing: String)(body: => Unit)(using Context): Unit =
       try body
       catch
-        case NonFatal(ex) =>
-          report.echo(s"exception occurred while $doing ${ctx.compilationUnit}")
+        case NonFatal(ex) if !ctx.run.enrichedErrorMessage =>
+          report.echo(ctx.run.enrichErrorMessage(s"exception occurred while $doing ${ctx.compilationUnit}"))
           throw ex
 
     override def toString: String = phaseName

compiler/src/dotty/tools/dotc/report.scala

@@ -151,7 +151,7 @@ object report:
 
     val info1 = formatExplain(List(
       "while compiling"    -> ctx.compilationUnit,
-      "during phase"       -> ctx.phase.prevMega,
+      "during phase"       -> ctx.phase.megaPhase,
       "mode"               -> ctx.mode,
       "library version"    -> scala.util.Properties.versionString,
       "compiler version"   -> dotty.tools.dotc.config.Properties.versionString,

compiler/src/dotty/tools/dotc/transform/TreeChecker.scala

@@ -89,7 +89,7 @@ class TreeChecker extends Phase with SymTransformer {
     if (ctx.phaseId <= erasurePhase.id) {
       val initial = symd.initial
       assert(symd == initial || symd.signature == initial.signature,
-        i"""Signature of ${sym} in ${sym.ownersIterator.toList}%, % changed at phase ${ctx.phase.prevMega}
+        i"""Signature of ${sym} in ${sym.ownersIterator.toList}%, % changed at phase ${ctx.phase.prev.megaPhase}
            |Initial info: ${initial.info}
            |Initial sig : ${initial.signature}
            |Current info: ${symd.info}
@@ -108,7 +108,7 @@ class TreeChecker extends Phase with SymTransformer {
       check(ctx.base.allPhases.toIndexedSeq, ctx)
 
   def check(phasesToRun: Seq[Phase], ctx: Context): Tree = {
-    val fusedPhase = ctx.phase.prevMega(using ctx)
+    val fusedPhase = ctx.phase.prev.megaPhase(using ctx)
     report.echo(s"checking ${ctx.compilationUnit} after phase ${fusedPhase}")(using ctx)
 
     inContext(ctx) {
@@ -129,7 +129,7 @@ class TreeChecker extends Phase with SymTransformer {
     catch {
       case NonFatal(ex) =>     //TODO CHECK. Check that we are bootstrapped
         inContext(checkingCtx) {
-          println(i"*** error while checking ${ctx.compilationUnit} after phase ${ctx.phase.prevMega(using ctx)} ***")
+          println(i"*** error while checking ${ctx.compilationUnit} after phase ${ctx.phase.prev.megaPhase(using ctx)} ***")
         }
         throw ex
     }

compiler/src/dotty/tools/dotc/typer/ReTyper.scala

@@ -145,7 +145,7 @@ class ReTyper(nestingLevel: Int = 0) extends Typer(nestingLevel) with ReChecking
   override def typedUnadapted(tree: untpd.Tree, pt: Type, locked: TypeVars)(using Context): Tree =
     try super.typedUnadapted(tree, pt, locked)
     catch case NonFatal(ex) if ctx.phase != Phases.typerPhase && ctx.phase != Phases.inliningPhase && !ctx.run.enrichedErrorMessage =>
-      val treeStr = tree.show(using ctx.withPhase(ctx.phase.prevMega))
+      val treeStr = tree.show(using ctx.withPhase(ctx.phase.prev.megaPhase))
       println(ctx.run.enrichErrorMessage(s"exception while retyping $treeStr of class ${tree.className} # ${tree.uniqueId}"))
       throw ex
 

compiler/src/dotty/tools/dotc/typer/TyperPhase.scala

@@ -46,11 +46,7 @@ class TyperPhase(addRootImports: Boolean = true) extends Phase {
         record("retained untyped trees", unit.untpdTree.treeSize)
         record("retained typed trees after typer", unit.tpdTree.treeSize)
         ctx.run.nn.suppressions.reportSuspendedMessages(unit.source)
-    catch
-      case ex: CompilationUnit.SuspendException =>
-      case ex: Throwable =>
-        println(s"$ex while typechecking $unit")
-        throw ex
+    catch case _: CompilationUnit.SuspendException => ()
   }
 
   def javaCheck(using Context): Unit = monitor("checking java") {