Corrects behavior of finalResultType.

The implementation had come to depend on finalResultType
accidentally doing things beyond its charter - in particular,
widening types. After hunting down and fixing the call sites
depending on the bugs, I was able to rewrite the method to do
only what it's supposed to do.

I threw in a different way of writing it entirely to suggest how
some correctness might be obtained in the future. It's a lot
harder for a method written like this to break.

1 files changed, 9 insertions, 0 deletions

diff --git a/test/files/pos/private-types-after-typer.scala b/test/files/pos/private-types-after-typer.scala
new file mode 100644
index 0000000000..79ef934063
--- /dev/null
+++ b/test/files/pos/private-types-after-typer.scala
@@ -0,0 +1,9 @@
+// Testing that the type of the outer accessor in O2
+// doesn't crash the compiler over private type escaping scope.
+trait T {
+  class C {
+     private object O1 {
+        object O2
+     }
+  }
+}
\ No newline at end of file