1 files changed, 59 insertions, 0 deletions
diff --git a/tests/run/t5879.scala b/tests/run/t5879.scala
new file mode 100644
index 000000000..f96a17410
--- /dev/null
+++ b/tests/run/t5879.scala
@@ -0,0 +1,59 @@
+import collection.immutable.HashMap
+
+
+object Test {
+
+  def main(args: Array[String]): Unit = {
+    resolveDefault()
+    resolveFirst()
+    resolveSecond()
+    resolveMany()
+  }
+
+  def resolveDefault(): Unit = {
+    val a = HashMap(1 -> "1")
+    val b = HashMap(1 -> "2")
+
+    val r = a.merged(b)(null)
+    println(r)
+    println(r(1))
+  }
+
+  def resolveFirst(): Unit = {
+    val a = HashMap(1 -> "1")
+    val b = HashMap(1 -> "2")
+    def collision(a: (Int, String), b: (Int, String)) = {
+      println(a)
+      a
+    }
+
+    val r = a.merged(b) { collision }
+    println(r)
+    println(r(1))
+  }
+
+  def resolveSecond(): Unit = {
+    val a = HashMap(1 -> "1")
+    val b = HashMap(1 -> "2")
+    def collision(a: (Int, String), b: (Int, String)) = {
+      println(b)
+      b
+    }
+
+    val r = a.merged(b) { collision }
+    println(r)
+    println(r(1))
+  }
+
+  def resolveMany(): Unit = {
+    val a = HashMap((0 until 100) zip (0 until 100): _*)
+    val b = HashMap((0 until 100) zip (100 until 200): _*)
+    def collision(a: (Int, Int), b: (Int, Int)) = {
+      (a._1, a._2 + b._2)
+    }
+
+    val r = a.merged(b) { collision }
+    for ((k, v) <- r) assert(v == 100 + 2 * k, (k, v))
+  }
+
+}