Merge pull request #3791 from S11001001/ticket/8346

SI-8346 Rebuild invariant sets in #toSet, avoiding CCE

2 files changed, 40 insertions, 0 deletions

diff --git a/test/files/run/t8346.check b/test/files/run/t8346.check
new file mode 100644
index 0000000000..1ba5c31abe
--- /dev/null
+++ b/test/files/run/t8346.check
@@ -0,0 +1,6 @@
+BitSet: List(invariant, invariant, invariant, invariant)
+HashSet: List(covariant (true), covariant (true), covariant (true), covariant (true))
+ListSet: List(covariant (true), covariant (true), covariant (true), covariant (true))
+SortedSet: List(invariant, invariant, invariant, invariant)
+TreeSet: List(invariant, invariant, invariant, invariant)
+ValueSet: invariant
diff --git a/test/files/run/t8346.scala b/test/files/run/t8346.scala
new file mode 100644
index 0000000000..5f3df84174
--- /dev/null
+++ b/test/files/run/t8346.scala
@@ -0,0 +1,34 @@
+object Test extends App {
+  import reflect.ClassTag
+
+  object SomeEnum extends Enumeration {
+    val one, two, three, four = Value
+  }
+
+  def sctor[A <: Set[Int]](f: Int => A)(implicit A: ClassTag[A])
+      : (String, Int => Set[Int]) =
+    (A.runtimeClass.getSimpleName, f)
+
+  val inits: Seq[(String, Int => Set[Int])] = {
+    import collection.immutable.{Seq => _, _}
+    Seq(sctor(BitSet(_)),
+        sctor(HashSet(_)),
+        sctor(ListSet(_)),
+        sctor(SortedSet(_)),
+        sctor(TreeSet(_)))
+  }
+
+  def sVarInfo[A](sa: Set[A]): String = {
+    val saa = sa.toSet[Any]
+    if (sa eq saa) s"""covariant (${(saa + "hi") contains "hi"})"""
+    else "invariant"
+  }
+
+  inits foreach {case (name, singleton) =>
+    print(s"${name}: ")
+    val one = singleton(1)
+    println(Seq(2,3,4).scanLeft(one)(_ + _) map sVarInfo toList)
+  }
+
+  println(s"ValueSet: ${sVarInfo(SomeEnum.values)}")
+}