SI-6853 changed private method remove to be tail recursive.

Operations += and -= on mutable.ListMap rely on the private method remove to perform. This methods was implemented using recursion, but it was not tail recursive. When the ListMap got too big the += caused a StackOverflowError.

1 files changed, 18 insertions, 0 deletions

diff --git a/test/files/run/t6853.scala b/test/files/run/t6853.scala
new file mode 100644
index 0000000000..352375c99c
--- /dev/null
+++ b/test/files/run/t6853.scala
@@ -0,0 +1,18 @@
+// Test cases: the only place we can cut and paste without crying
+// ourself to sleep.
+object Test {
+
+  def main(args: Array[String]): Unit = {
+    // First testing the basic operations
+    val m = collection.mutable.ListMap[String, Int]()
+    var i = 0
+    while(i < 2) { m += ("foo" + i) -> i; i = i+1}
+    assert(m == Map("foo1"->1,"foo0"->0))
+    m-= "foo0"
+    assert(m == Map("foo1"->1))
+    // Now checking if it scales as described in SI-6853
+    i = 0
+    while(i < 80000) { m += ("foo" + i) -> i; i = i+1}
+    assert(m.size == 80000)
+  }
+}