Fix some warnings

Author: satabin

build.sbt

@@ -8,6 +8,8 @@ val scalacheckVersion = "1.17.0"
 ThisBuild / scalaVersion := scala213
 ThisBuild / crossScalaVersions := Seq(scala212, scala213, scala3)
 
+ThisBuild / tlFatalWarnings := false
+
 ThisBuild / tlBaseVersion := "4.1"
 
 ThisBuild / organization := "org.gnieh"

core/src/main/scala/diffson/jsonmergepatch/package.scala

@@ -16,12 +16,8 @@
 
 package diffson
 
-import lcs.Lcs
-
 import cats._
 
-import scala.language.higherKinds
-
 package object jsonmergepatch {
 
   implicit def JsonMergePatchPatch[F[_], Json](implicit

core/src/main/scala/diffson/jsonpatch/JsonPatch.scala

@@ -23,7 +23,6 @@ import cats._
 import cats.implicits._
 
 import scala.annotation.tailrec
-import scala.language.higherKinds
 
 /** A patch operation to apply to a Json value */
 sealed abstract class Operation[Json: Jsony] {

core/src/main/scala/diffson/jsonpatch/package.scala

@@ -18,10 +18,6 @@ package diffson
 
 import lcs.Lcs
 
-import cats._
-
-import scala.language.higherKinds
-
 package object jsonpatch {
 
   object lcsdiff {

core/src/main/scala/diffson/jsonpointer/package.scala

@@ -17,12 +17,11 @@
 package diffson
 
 import cats._
-import cats.implicits._
+import cats.syntax.all._
 import cats.data.Chain
 
 import scala.util.Try
 
-import scala.language.{implicitConversions, higherKinds}
 import scala.collection.compat._
 import scala.collection.compat.immutable.ArraySeq
 
@@ -46,7 +45,7 @@ package object jsonpointer {
             // we know (by construction) that the index is greater or equal to zero
             F.raiseError(new PointerException(show"element $idx does not exist at path $parent"))
           else
-            F.pure(Left(arr(idx), tl, parent / idx))
+            F.pure(Left((arr(idx), tl, parent / idx)))
         case (value, Pointer.Root, _) =>
           F.pure(Right(value))
         case (_, Inner(elem, _), parent) =>
@@ -58,15 +57,18 @@ package object jsonpointer {
 
   object Pointer {
 
-    val Root: Pointer = Pointer(Chain.empty)
+    val Root: Pointer = new Pointer(Chain.empty)
 
     private val IsNumber = "(0|[1-9][0-9]*)".r
 
-    def apply(elems: String*): Pointer = Pointer(Chain.fromSeq(elems.map {
+    def apply(elems: String*): Pointer = new Pointer(Chain.fromSeq(elems.map {
       case s @ IsNumber(idx) => Try(idx.toInt).liftTo[Either[Throwable, *]].leftMap(_ => s)
       case key               => Left(key)
     }))
 
+    def unapply(p: Pointer): Some[Chain[Part]] =
+      Some(p.parts)
+
     def parse[F[_]](input: String)(implicit F: MonadError[F, Throwable]): F[Pointer] =
       if (input == null || input.isEmpty) {
         // shortcut if input is empty