explicit implicits in tests

Author: sideeffffect

src/test/scala/zio/prelude/NewtypeSpec.scala

@@ -15,7 +15,7 @@ object NewtypeSpec extends DefaultRunnableSpec {
   // Age.newtype.Type with Age.Instances
   type Age = Age.Type
 
-  implicitly[Dummy[Age]]
+  val _ = implicitly[Dummy[Age]]
 
   def spec =
     suite("NewtypeSpec")(

src/test/scala/zio/prelude/TraversableSpec.scala

@@ -104,7 +104,10 @@ object TraversableSpec extends DefaultRunnableSpec {
         },
         testM("groupByM") {
           check(genList, genIntFunction) { (as, f) =>
-            val actual   = Traversable[List].groupByM(as)(f.map(Option(_)))
+            val actual   = Traversable[List].groupByM(as)(f.map(Option(_))(Covariant.Function1Covariant[Int]))(
+              IdentityBoth.OptionIdentityBoth,
+              Covariant.OptionCovariant
+            )
             val expected = Option(
               as.groupBy(f)
                 .toList