Tests for QuicklensMapAtFunctor implicits

quicklens/src/main/scala-2.13+/com.softwaremill.quicklens/package.scala

@@ -310,6 +310,9 @@ sealed trait LowPriorityImplicits {
 
   import quicklens._
 
+  /**
+    * `QuicklensEach` is in `LowPriorityImplicits` to not conflict with the `QuicklensMapAtFunctor` on `each` calls.
+    */
   implicit class QuicklensEach[F[_], T](t: F[T])(implicit f: QuicklensFunctor[F, T]) {
     @compileTimeOnly(canOnlyBeUsedInsideModify("each"))
     def each: T = sys.error("")

quicklens/src/main/scala-2.13-/com.softwaremill.quicklens/package.scala

@@ -315,6 +315,9 @@ sealed trait LowPriorityImplicits {
 
   import quicklens._
 
+  /**
+    * `QuicklensEach` is in `LowPriorityImplicits` to not conflict with the `QuicklensMapAtFunctor` on `each` calls.
+    */
   implicit class QuicklensEach[F[_], T](t: F[T])(implicit f: QuicklensFunctor[F, T]) {
     @compileTimeOnly(canOnlyBeUsedInsideModify("each"))
     def each: T = sys.error("")

quicklens/src/test/scala-2/com.softwaremill.quicklens/QuicklensMapAtFunctorTest.scala

@@ -0,0 +1,28 @@
+package com.softwaremill.quicklens
+
+import com.softwaremill.quicklens.TestData._
+import org.scalatest.flatspec.AnyFlatSpec
+import org.scalatest.matchers.should.Matchers
+
+class QuicklensMapAtFunctorTest extends AnyFlatSpec with Matchers {
+
+  "QuicklensMapAtFunctor" should "work for types which is not a subtype of Map" in {
+    case class MapLike[K, V](underlying: Map[K, V])
+
+    implicit def instance[K, T]: QuicklensMapAtFunctor[MapLike, K, T] = new QuicklensMapAtFunctor[MapLike, K, T] {
+      private val mapInstance: QuicklensMapAtFunctor[Map, K, T] =
+        implicitly[QuicklensMapAtFunctor[Map, K, T]]
+
+      def at(fa: MapLike[K, T], idx: K)(f: T => T): MapLike[K, T] =
+        MapLike(mapInstance.at(fa.underlying, idx)(f))
+      def atOrElse(fa: MapLike[K, T], idx: K, default: => T)(f: T => T): MapLike[K, T] =
+        MapLike(mapInstance.atOrElse(fa.underlying, idx, default)(f))
+      def index(fa: MapLike[K, T], idx: K)(f: T => T): MapLike[K, T] =
+        MapLike(mapInstance.index(fa.underlying, idx)(f))
+      def each(fa: MapLike[K, T])(f: T => T): MapLike[K, T] =
+        MapLike(mapInstance.each(fa.underlying)(f))
+    }
+
+    modify(MapLike(m1))(_.at("K1").a5.name).using(duplicate) should be(MapLike(m1dup))
+  }
+}