1 files changed, 38 insertions, 0 deletions
diff --git a/tests/run/t978.scala b/tests/run/t978.scala
new file mode 100644
index 000000000..e87e7054a
--- /dev/null
+++ b/tests/run/t978.scala
@@ -0,0 +1,38 @@
+class Foo(val n: Int) {
+  override def hashCode = n % 2 // pretty bad hash
+  override def equals(other: Any): Boolean = other match {
+    case f: Foo => f.n == n
+    case _ => false
+  }
+
+  override def toString = "" + n
+}
+
+object Test extends dotty.runtime.LegacyApp {
+  val set = new collection.mutable.HashSet[Foo]
+//  val set = new collection.jcl.HashSet[Foo]
+
+  val max = 200
+  for (x <- 1 to max)
+    set += new Foo(x)
+
+  testRemove(2)
+  testExists(2)
+
+  def testRemove(m: Int): Unit = {
+    for (x <- 1 to max; if x % m == 0) {
+      val f = new Foo(x)
+      set -= f
+      assert(!(set contains f))
+      testExists(m)
+    }
+  }
+
+  def testExists(m: Int): Unit = {
+    for (x <- 1 to max; if x % m == 1) {
+      val f = new Foo(x)
+      assert(set contains f, "For element: " + f + " set: " + set)
+    }
+  }
+
+}