Merge pull request #214 from OndrejSpanel/master

Enable `at` with a derived key in Scala 3
softwaremill · Jan 23, 2024 · a1f561c · a1f561c
2 parents 483bbe7 + a6f0a5c
commit a1f561c
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diff --git a/quicklens/src/main/scala-3/com/softwaremill/quicklens/package.scala b/quicklens/src/main/scala-3/com/softwaremill/quicklens/package.scala
@@ -161,7 +161,7 @@ package object quicklens {
     }
   }
 
-  trait QuicklensIndexedFunctor[F[_], I] {
+  trait QuicklensIndexedFunctor[F[_], -I] {
     def at[A](fa: F[A], f: A => A, idx: I): F[A]
     def atOrElse[A](fa: F[A], f: A => A, idx: I, default: => A): F[A]
     def index[A](fa: F[A], f: A => A, idx: I): F[A]

diff --git a/quicklens/src/test/scala/com/softwaremill/quicklens/ModifyMapAtTest.scala b/quicklens/src/test/scala/com/softwaremill/quicklens/ModifyMapAtTest.scala
@@ -57,4 +57,12 @@ class ModifyMapAtTest extends AnyFlatSpec with Matchers {
       modify(m1)(_.at("K0").a5.name).using(duplicate)
     }
   }
+
+  it should "modify a map using at with a derived class" in {
+    class C
+    object D extends C
+    val m = Map[C, String](D -> "")
+    val expected = Map(D -> "x")
+    modify(m)(_.at(D)).setTo("x") should be(expected)
+  }
 }