A zero cost, type-safe equals function in scala

SafeEq.scala

import scala.language.experimental.macros
import scala.reflect.macros.Context

/**
 * you can try this in the REPL even
 */
object SafeEq {
  /**
   * eqv(1, "foo") won't compile
   */
  def eqv[A, B](a: A, b: B): Boolean = macro eqvMacro[A, B]
  def eqvMacro[A, B](c: Context)(
    a: c.Expr[A],
    b: c.Expr[B])(implicit A: c.WeakTypeTag[A], B: c.WeakTypeTag[B]): c.Expr[Boolean] = {
      import c.universe._
      if (A == B) c.Expr[Boolean](q"""$a == $b""")
      else c.abort(c.enclosingPosition, s"types: $A and $B do not match")
    }
}

Interesting. What's the advantage over the approach used by the === operator in spire? Here is the macro I use: https://github.com/non/spire/blob/master/macros/src/main/scala/spire/macros/Syntax.scala#L46

I think the performance characteristics should be the same, so I guess it is a matter of taste if you want the =:= in the type signature or not.