diff --git a/src/library/scala/collection/Map.scala b/src/library/scala/collection/Map.scala
index cb8fa455e7e7..ab686f42822c 100644
--- a/src/library/scala/collection/Map.scala
+++ b/src/library/scala/collection/Map.scala
@@ -311,7 +311,7 @@ trait MapOps[K, +V, +CC[_, _] <: IterableOps[_, AnyConstr, _], +C]
   }
 
   @deprecated("Use ++ instead of ++: for collections of type Iterable", "2.13.0")
-  def ++: [V1 >: V](that: IterableOnce[(K,V1)]): CC[K,V1] = {
+  def ++: [V1 >: V](that: IterableOnce[(K,V1)])(implicit dummy: DummyImplicit): CC[K,V1] = {
     val thatIterable: Iterable[(K, V1)] = that match {
       case that: Iterable[(K, V1)] => that
       case that => View.from(that)