Fix and test case for #2512, plus lots of time ...

Fix and test case for #2512, plus lots of time expended tuning HashSet
starting sizes and growth rate, with almost nothing to show for it (but
I did determine that "shadowed" is constructed identically something
like 10,000 times, so there is probably a cache to be had there.)

1 files changed, 14 insertions, 0 deletions

diff --git a/test/files/run/bug2512.scala b/test/files/run/bug2512.scala
new file mode 100644
index 0000000000..514b26650f
--- /dev/null
+++ b/test/files/run/bug2512.scala
@@ -0,0 +1,14 @@
+import scala.tools.nsc.util.HashSet
+
+object Test
+{
+  val runs = 10000
+  class Bop
+
+  def main(args: Array[String]): Unit = {
+    val set: HashSet[Bop] = new HashSet("Bop", 16)
+    (1 to runs).toList foreach (_ => set addEntry new Bop)
+
+    assert(runs == set.size && set.size == set.iterator.length)
+  }
+}