Merge pull request #6103 from dotty-staging/fix-#6059

Fix #6059: Use correct errors-reported condition in Desugar

Author: odersky

compiler/src/dotty/tools/dotc/ast/Desugar.scala

@@ -1363,7 +1363,7 @@ object desugar {
             AppliedTypeTree(ref(seqType), t),
             New(ref(defn.RepeatedAnnotType), Nil :: Nil))
         } else {
-          assert(ctx.mode.isExpr || ctx.reporter.hasErrors || ctx.mode.is(Mode.Interactive), ctx.mode)
+          assert(ctx.mode.isExpr || ctx.reporter.errorsReported || ctx.mode.is(Mode.Interactive), ctx.mode)
           Select(t, op.name)
         }
       case PrefixOp(op, t) =>

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

@@ -287,6 +287,10 @@ object Phases {
 
     def isRunnable(implicit ctx: Context): Boolean =
       !ctx.reporter.hasErrors
+        // TODO: This might test an unintended condition.
+        // To find out whether any errors have been reported during this
+        // run one calls `errorsReported`, not `hasErrors`.
+        // But maybe changing this would prevent useful phases from running?
 
     /** If set, allow missing or superfluous arguments in applications
      *  and type applications.

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

@@ -98,8 +98,9 @@ trait Reporting { this: Context =>
     else reportWarning(new ExtendMessage(() => msg)(_ + "\n(This would be an error under strict mode)").warning(fullPos))
   }
 
-  def error(msg: => Message, pos: SourcePosition = NoSourcePosition): Unit =
+  def error(msg: => Message, pos: SourcePosition = NoSourcePosition): Unit = {
     reporter.report(new Error(msg, addInlineds(pos)))
+  }
 
   def errorOrMigrationWarning(msg: => Message, pos: SourcePosition = NoSourcePosition): Unit = {
     val fullPos = addInlineds(pos)
@@ -184,11 +185,22 @@ abstract class Reporter extends interfaces.ReporterResult {
 
   private[this] var _errorCount = 0
   private[this] var _warningCount = 0
+
+  /** The number of errors reported by this reporter (ignoring outer reporters) */
   def errorCount: Int = _errorCount
+
+  /** The number of warnings reported by this reporter (ignoring outer reporters) */
   def warningCount: Int = _warningCount
+
+  /** Have errors been reported by this reporter (ignoring outer reporters)? */
   def hasErrors: Boolean = errorCount > 0
+
+  /** Have warnings been reported by this reporter (ignoring outer reporters)? */
   def hasWarnings: Boolean = warningCount > 0
+
   private[this] var errors: List[Error] = Nil
+
+  /** All errors reported by this reporter (ignoring outer reporters) */
   def allErrors: List[Error] = errors
 
   /** Have errors been reported by this reporter, or in the

tests/neg/i6059.scala

@@ -0,0 +1,3 @@
+def I0(I1: Int ) = I1
+val I1 = I0(I0 i2  // error
+) => true