Fix #866

src/dotty/tools/dotc/Driver.scala

@@ -12,7 +12,7 @@ abstract class Driver extends DotClass {
 
   protected def newCompiler(): Compiler
 
-  protected def emptyReporter: Reporter = new StoreReporter
+  protected def emptyReporter: Reporter = new StoreReporter(null)
 
   protected def doCompile(compiler: Compiler, fileNames: List[String])(implicit ctx: Context): Reporter =
     if (fileNames.nonEmpty)
@@ -24,7 +24,7 @@ abstract class Driver extends DotClass {
       catch {
         case ex: FatalError  =>
           ctx.error(ex.getMessage) // signals that we should fail compilation.
-          ctx.typerState.reporter
+          ctx.reporter
       }
     else emptyReporter
 

src/dotty/tools/dotc/Resident.scala

@@ -47,7 +47,7 @@ class Resident extends Driver {
         nextCtx = rootCtx
         line = getLine()
       }
-      if (line.startsWith(quit)) ctx.typerState.reporter
+      if (line.startsWith(quit)) ctx.reporter
       else loop(line split "\\s+", nextCtx)
     }
     loop(args, rootCtx)

src/dotty/tools/dotc/Run.scala

@@ -84,7 +84,7 @@ class Run(comp: Compiler)(implicit ctx: Context) {
   /** Print summary; return # of errors encountered */
   def printSummary(): Reporter = {
     ctx.runInfo.printMaxConstraint()
-    val r = ctx.typerState.reporter
+    val r = ctx.reporter
     r.printSummary
     r
   }

src/dotty/tools/dotc/ast/Trees.scala

@@ -146,7 +146,7 @@ object Trees {
      *  type. (Overridden by empty trees)
      */
     def withType(tpe: Type)(implicit ctx: Context): ThisTree[Type] = {
-      if (tpe == ErrorType) assert(ctx.errorsReported)
+      if (tpe == ErrorType) assert(ctx.reporter.errorsReported)
       withTypeUnchecked(tpe)
     }
 

src/dotty/tools/dotc/core/TyperState.scala

@@ -98,7 +98,7 @@ extends TyperState(r) {
 
 
   override def fresh(isCommittable: Boolean): TyperState =
-    new MutableTyperState(this, new StoreReporter, isCommittable)
+    new MutableTyperState(this, new StoreReporter(reporter), isCommittable)
 
   override def withReporter(reporter: Reporter) =
     new MutableTyperState(this, reporter, isCommittable)
@@ -169,7 +169,7 @@ extends TyperState(r) {
    *  found a better solution.
    */
   override def tryWithFallback[T](op: => T)(fallback: => T)(implicit ctx: Context): T = {
-    val storeReporter = new StoreReporter
+    val storeReporter = new StoreReporter(myReporter)
     val savedReporter = myReporter
     myReporter = storeReporter
     val savedConstraint = myConstraint

src/dotty/tools/dotc/reporting/ConsoleReporter.scala

@@ -40,8 +40,9 @@ class ConsoleReporter(
     }
   }
 
-  override def doReport(d: Diagnostic)(implicit ctx: Context): Unit =
-    if (!d.isSuppressed || !hasErrors) d match {
+  override def doReport(d: Diagnostic)(implicit ctx: Context): Boolean = {
+    val issue = !(d.isSuppressed && hasErrors)
+    if (issue) d match {
       case d: Error =>
         printMessageAndPos(s"error: ${d.msg}", d.pos)
         if (ctx.settings.prompt.value) displayPrompt()
@@ -51,6 +52,8 @@ class ConsoleReporter(
       case _ =>
         printMessageAndPos(d.msg, d.pos)
     }
+    issue
+  }
 
   def displayPrompt(): Unit = {
     writer.print("\na)bort, s)tack, r)esume: ")

src/dotty/tools/dotc/reporting/Reporter.scala

@@ -173,8 +173,6 @@ trait Reporting { this: Context =>
         throw ex
     }
   }
-
-  def errorsReported: Boolean = outersIterator exists (_.reporter.hasErrors)
 }
 
 /**
@@ -183,8 +181,10 @@ trait Reporting { this: Context =>
  */
 abstract class Reporter {
 
-  /** Report a diagnostic */
-  def doReport(d: Diagnostic)(implicit ctx: Context): Unit
+  /** Report a diagnostic, unless it is suppressed because it is nonsensical
+   *  @return a diagnostic was reported.
+   */
+  def doReport(d: Diagnostic)(implicit ctx: Context): Boolean
 
  /** Whether very long lines can be truncated.  This exists so important
    *  debugging information (like printing the classpath) is not rendered
@@ -213,20 +213,24 @@ abstract class Reporter {
   def hasErrors = errorCount > 0
   def hasWarnings = warningCount > 0
 
+  /** Have errors been reported by this reporter, or in the
+   *  case where this is a StoreReporter, by an outer reporter?
+   */
+  def errorsReported = hasErrors
+
   val unreportedWarnings = new mutable.HashMap[String, Int] {
     override def default(key: String) = 0
   }
 
-  def report(d: Diagnostic)(implicit ctx: Context): Unit = if (!isHidden(d)) {
-    doReport(d)(ctx.addMode(Mode.Printing))
-    d match {
-      case d: ConditionalWarning if !d.enablingOption.value => unreportedWarnings(d.enablingOption.name) += 1
-      case d: Warning => warningCount += 1
-      case d: Error => errorCount += 1
-      case d: Info => // nothing to do here
-      // match error if d is something else
-    }
-  }
+  def report(d: Diagnostic)(implicit ctx: Context): Unit =
+    if (!isHidden(d) && doReport(d)(ctx.addMode(Mode.Printing)))
+      d match {
+        case d: ConditionalWarning if !d.enablingOption.value => unreportedWarnings(d.enablingOption.name) += 1
+        case d: Warning => warningCount += 1
+        case d: Error => errorCount += 1
+        case d: Info => // nothing to do here
+        // match error if d is something else
+      }
 
   def incomplete(d: Diagnostic)(implicit ctx: Context): Unit =
     incompleteHandler(d)(ctx)

src/dotty/tools/dotc/reporting/StoreReporter.scala

@@ -10,14 +10,15 @@ import config.Printers._
 /**
  * This class implements a Reporter that stores all messages
  */
-class StoreReporter extends Reporter {
+class StoreReporter(outer: Reporter) extends Reporter {
 
   private var infos: mutable.ListBuffer[Diagnostic] = null
 
-  def doReport(d: Diagnostic)(implicit ctx: Context): Unit = {
+  def doReport(d: Diagnostic)(implicit ctx: Context): Boolean = {
     typr.println(s">>>> StoredError: ${d.msg}") // !!! DEBUG
     if (infos == null) infos = new mutable.ListBuffer
     infos += d
+    true
   }
 
   override def hasPending: Boolean = infos != null && {
@@ -33,4 +34,6 @@ class StoreReporter extends Reporter {
       infos foreach ctx.reporter.report
       infos = null
     }
+
+  override def errorsReported = hasErrors || outer.errorsReported
 }

src/dotty/tools/dotc/reporting/ThrowingReporter.scala

@@ -11,7 +11,7 @@ import Reporter._
  * info to the underlying reporter.
  */
 class ThrowingReporter(reportInfo: Reporter) extends Reporter {
-  def doReport(d: Diagnostic)(implicit ctx: Context): Unit = d match {
+  def doReport(d: Diagnostic)(implicit ctx: Context): Boolean = d match {
     case _: Error => throw d
     case _ => reportInfo.doReport(d)
   }

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

@@ -118,7 +118,7 @@ class TreeChecker extends Phase with SymTransformer {
     val squahsedPhase = ctx.squashed(prevPhase)
     ctx.println(s"checking ${ctx.compilationUnit} after phase ${squahsedPhase}")
     val checkingCtx = ctx.fresh
-      .setTyperState(ctx.typerState.withReporter(new ThrowingReporter(ctx.typerState.reporter)))
+      .setTyperState(ctx.typerState.withReporter(new ThrowingReporter(ctx.reporter)))
     val checker = new Checker(previousPhases(phasesToRun.toList)(ctx))
     try checker.typedExpr(ctx.compilationUnit.tpdTree)(checkingCtx)
     catch {

src/dotty/tools/dotc/typer/Applications.scala

@@ -153,7 +153,7 @@ trait Applications extends Compatibility { self: Typer =>
 
     def ok = _ok
     def ok_=(x: Boolean) = {
-      assert(x || ctx.errorsReported || !ctx.typerState.isCommittable) // !!! DEBUG
+      assert(x || ctx.reporter.errorsReported || !ctx.typerState.isCommittable) // !!! DEBUG
       _ok = x
     }
 

src/dotty/tools/dotc/typer/Implicits.scala

@@ -495,7 +495,7 @@ trait Implicits { self: Typer =>
               case _ => false
             }
           }
-        if (ctx.typerState.reporter.hasErrors)
+        if (ctx.reporter.hasErrors)
           nonMatchingImplicit(ref)
         else if (contextual && !ctx.mode.is(Mode.ImplicitShadowing) &&
                  !shadowing.tpe.isError && !refMatches(shadowing)) {

test/dotc/tests.scala

@@ -109,8 +109,8 @@ class tests extends CompilerTest {
   @Test def neg_privates() = compileFile(negDir, "privates", xerrors = 2)
   @Test def neg_rootImports = compileFile(negDir, "rootImplicits", xerrors = 2)
   @Test def neg_templateParents() = compileFile(negDir, "templateParents", xerrors = 3)
-  @Test def neg_autoTupling = compileFile(posDir, "autoTuplingTest", args = "-language:noAutoTupling" :: Nil, xerrors = 4)
-  @Test def neg_autoTupling2 = compileFile(negDir, "autoTuplingTest", xerrors = 4)
+  @Test def neg_autoTupling = compileFile(posDir, "autoTuplingTest", args = "-language:noAutoTupling" :: Nil, xerrors = 3)
+  @Test def neg_autoTupling2 = compileFile(negDir, "autoTuplingTest", xerrors = 3)
   @Test def neg_companions = compileFile(negDir, "companions", xerrors = 1)
   @Test def neg_over = compileFile(negDir, "over", xerrors = 3)
   @Test def neg_overrides = compileFile(negDir, "overrides", xerrors = 11)
@@ -145,6 +145,7 @@ class tests extends CompilerTest {
   @Test def neg_i583 = compileFile(negDir, "i0583-skolemize", xerrors = 2)
   @Test def neg_finalSealed = compileFile(negDir, "final-sealed", xerrors = 2)
   @Test def neg_i705 = compileFile(negDir, "i705-inner-value-class", xerrors = 7)
+  @Test def neg_i866 = compileFile(negDir, "i866", xerrors = 2)
   @Test def neg_moduleSubtyping = compileFile(negDir, "moduleSubtyping", xerrors = 4)
   @Test def neg_escapingRefs = compileFile(negDir, "escapingRefs", xerrors = 2)
   @Test def neg_instantiateAbstract = compileFile(negDir, "instantiateAbstract", xerrors = 8)

tests/neg/i866.scala

@@ -0,0 +1,9 @@
+object Test {
+  def x: Int = ""     // error
+}
+import nonexistent._  // error; this one will swallow all errors below.
+object Foo {
+  def bar(implicit x: NonExistent) = ???
+  val baz = bar
+}
+