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, 3 insertions, 1 deletions

diff --git a/src/dotty/tools/dotc/reporting/StoreReporter.scala b/src/dotty/tools/dotc/reporting/StoreReporter.scala
index 51d3df110..1991790b5 100644
--- a/src/dotty/tools/dotc/reporting/StoreReporter.scala
+++ b/src/dotty/tools/dotc/reporting/StoreReporter.scala
@@ -10,7 +10,7 @@ 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
 
@@ -33,4 +33,6 @@ class StoreReporter extends Reporter {
       infos foreach ctx.reporter.report
       infos = null
     }
+
+  override def errorsReported = hasErrors || outer.errorsReported
 }