Keep separate chain of outer reporters for StoreReporters

Used in rewritten `errorsReported` method. This fixes #866. The problem
before was that `TyperState#trywithFallBack` temporarily updates
the reporter, so crawling up the context chain to check for reporters
with errors missed some reported errors, which triggered the assertion
in `Tree#withType`.

1 files changed, 5 insertions, 2 deletions

diff --git a/src/dotty/tools/dotc/reporting/Reporter.scala b/src/dotty/tools/dotc/reporting/Reporter.scala
index 086575fb4..7c9d1fa79 100644
--- a/src/dotty/tools/dotc/reporting/Reporter.scala
+++ b/src/dotty/tools/dotc/reporting/Reporter.scala
@@ -173,8 +173,6 @@ trait Reporting { this: Context =>
         throw ex
     }
   }
-
-  def errorsReported: Boolean = outersIterator exists (_.reporter.hasErrors)
 }
 
 /**
@@ -213,6 +211,11 @@ 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
   }