Merge pull request #1022 from playframework/mergify/bp/2.10.x/pr-993

[2.10.x] Fix #974 – Scala 3 macro cannot find Writes for Seq[Map[String, T]] (backport #993) by @sgodbillon
playframework · Apr 29, 2024 · 01b3cce · 01b3cce
2 parents 3fca971 + eed1458
commit 01b3cce
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diff --git a/play-json/shared/src/main/scala/play/api/libs/json/Writes.scala b/play-json/shared/src/main/scala/play/api/libs/json/Writes.scala
@@ -366,7 +366,7 @@ 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
+  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]]

diff --git a/play-json/shared/src/test/scala/play/api/libs/json/WritesSharedSpec.scala b/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 {