Better handling of deriving equality

src/main/scala/logic/Kinds.scala

@@ -1,11 +1,9 @@
 package Prover
 
-sealed trait Kind
+sealed trait Kind derives CanEqual
 case object TyKind                  extends Kind
 case class ConstructorKind(k: Kind) extends Kind
 
-given CanEqual[Kind, Kind] = CanEqual.derived
-
 object TyFunctionKind:
     def apply(): Kind = ConstructorKind(TyKind)
     def unapply(kind: Kind): Boolean =

src/main/scala/logic/Taint.scala

@@ -1,13 +1,11 @@
 package Prover
 
-sealed trait Taint
+sealed trait Taint derives CanEqual
 case object I  extends Taint
 case object W  extends Taint
 case object C  extends Taint
 case object CH extends Taint
 
-given CanEqual[Taint, Taint] = CanEqual.derived
-
 // Taint semilattice has this order:
 //
 //   CH

src/main/scala/logic/Term.scala

@@ -1,13 +1,11 @@
 package Prover
 
-sealed trait Term
+sealed trait Term derives CanEqual
 case class Var(name: String, ty: Ty) extends Term { override def toString: String = s"${name}"      } // ^${ty.toString}" }
 case class Const(c: String, ty: Ty)  extends Term { override def toString: String = s"${c}"         }
 case class App(l: Term, r: Term)     extends Term { override def toString: String = s"(${l}, ${r})" }
 case class Lam(x: Var, body: Term)   extends Term
 
-given CanEqual[Term, Term] = CanEqual.derived
-
 object Term:
 
     def ftv(t: Term): Set[TyVar] =

src/main/scala/logic/Ty.scala

@@ -1,12 +1,10 @@
 package Prover
 
-sealed trait Ty
+sealed trait Ty derives CanEqual
 case class TyVar(name: String)                extends Ty { override def toString: String = s"${name}"    }
 case class TyFormer(name: String, kind: Kind) extends Ty { override def toString: String = s""           } //[${name}:${kind.toString}]" }
 case class TyApp(l: Ty, r: Ty)                extends Ty { override def toString: String = s"(${l}${r})" }
 
-given CanEqual[Ty, Ty] = CanEqual.derived
-
 object Ty:
 
     def ftv(ty: Ty): Set[TyVar] =