Fix #974 – Scala 3 macro cannot find Writes for Seq[Map[String, T]]

Moved the deprecated method `DefaultWrites.mapWrites` into `LowPriorityWrites` to get rid of the ambiguity.

play-json/shared/src/main/scala/play/api/libs/json/Writes.scala

@@ -362,12 +362,6 @@ trait DefaultWrites extends LowPriorityWrites with EnumerationWrites {
     }
   }
 
-  /**
-   * Serializer for Map[String,V] types.
-   */
-  @deprecated("Use `genericMapWrites`", "2.8.0")
-  implicit def mapWrites[V: Writes]: OWrites[MapWrites.Map[String, V]] = MapWrites.mapWrites
-
   implicit def keyMapWrites[K: KeyWrites, V: Writes, M[K, V] <: MapWrites.Map[K, V]]: OWrites[M[K, V]] = {
     val kw = implicitly[KeyWrites[K]]
     val vw = implicitly[Writes[V]]
@@ -521,6 +515,12 @@ sealed trait LowPriorityWrites extends EnvWrites {
   def iterableWrites[A, M[T] <: Iterable[T]](implicit w: Writes[A]): Writes[M[A]] =
     iterableWrites2[A, M[A]]
 
+  /**
+   * Serializer for Map[String,V] types.
+   */
+  @deprecated("Use `genericMapWrites`", "2.8.0")
+  implicit def mapWrites[V: Writes]: OWrites[MapWrites.Map[String, V]] = MapWrites.mapWrites
+
   /**
    * Serializer for Iterable types.
    */

play-json/shared/src/test/scala/play/api/libs/json/WritesSharedSpec.scala

@@ -84,6 +84,10 @@ final class WritesSharedSpec extends AnyWordSpec with Matchers {
     "write lazy maps" in {
       Json.toJson(Map("a" -> 1).map(kv => kv._1 -> (kv._2 + 1))).mustEqual(Json.obj("a" -> 2))
     }
+
+    "write a map nested in a seq" in {
+      Json.toJson(Seq(Map("a" -> 1))).mustEqual(Json.arr(Json.obj("a" -> 1)))
+    }
   }
 
   "Iterable writes" should {