SI-7498 ParTrieMap.foreach no longer crashes

Previously, the `split` method of the `ParTrieMap` iterator threw
an exception when splitting a splitter that iterated over nodes
whose hash codes collide.
This was due to reusing the iterator of the list of colliding keys
rather than creating a new splitter.

This commit changes the `subdivide` method to create a new
iterator using the factory method of the current trie map
iterator rather than returning a `LinearSeqLike` iterator.

1 files changed, 20 insertions, 0 deletions

diff --git a/test/files/run/t7498.scala b/test/files/run/t7498.scala
new file mode 100644
index 0000000000..1dbf0597e0
--- /dev/null
+++ b/test/files/run/t7498.scala
@@ -0,0 +1,20 @@
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+object Test extends App {
+  import scala.collection.concurrent.TrieMap
+
+  class Collision(val idx: Int) {
+    override def hashCode = idx % 10
+  }
+
+  val tm = TrieMap[Collision, Unit]()
+  for (i <- 0 until 1000) tm(new Collision(i)) = ()
+
+  tm.par.foreach(kv => ())
+}
+