Fix mergeDenot one more time.

It's easy to get this wrong. What happened was that when
computing deferred members of a class a deferred member
was preferred over a concrete one because the types did not match.
Thsi should not happen. We now change the scheme to always
prefer concrete over abstract, and subclass-owned over superclass-owned.
But we pick a denotation only if the overrides relationship on types
coincides with the preference on symbols.

1 files changed, 27 insertions, 0 deletions

diff --git a/tests/pos/t5577.scala b/tests/pos/t5577.scala
new file mode 100644
index 000000000..d54a37e45
--- /dev/null
+++ b/tests/pos/t5577.scala
@@ -0,0 +1,27 @@
+
+
+
+import collection._
+
+
+
+object Test {
+
+  class AlarmingBuffer[T] extends mutable.ArrayBuffer[T] {
+    override def sizeHint(x: Int): Unit = {
+      println("Received a size hint: " + x)
+      super.sizeHint(x)
+    }
+  }
+
+  def main(args: Array[String]): Unit = {
+    val iteratorBuilder = (new AlarmingBuffer[Int]) mapResult {
+      res => res.iterator
+    }
+
+    iteratorBuilder.sizeHint(10)
+    iteratorBuilder ++= (0 until 10)
+    iteratorBuilder.result.foreach(println)
+  }
+
+}