package scala

import annotation.implicitNotFound

/** A marker trait indicating that values of type `L` can be compared to values of type `R`. */
@implicitNotFound("Values of types ${L} and ${R} cannot be compared with == or !=")
sealed trait Eq[-L, -R]

/** Besides being a companion object, this object
 *  can also be used as a value that's compatible with
 *  any instance of `Eq`.
 */
object Eq extends Eq[Any, Any]