Better error messages for extension methods, showing "overloaded" alternatives (when implicit search fails)

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work-in progress:
Many libraries like Slick and shapeless make extensive use of implicit-driven method extensions for types. When implicit search fails error messages could be much more helpful. Ideally, users should be supported in detecting and correcting:

1. providing wrong arguments to an (extension) method
2. passing valid arguments to an existing (extension) method which a requires an implicit that cannot be found
   This could probably be done by letting implicit search keep a list of methods that were found because the name matched but neglected due to wrong arguments and missing implicits. The list could be displayed to the user similar to showing overloads in case of an error.

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Imported From: https://issues.scala-lang.org/browse/SI-7906?orig=1
Reporter: @cvogt
Affected Versions: 2.10.3, 2.11.0-M5

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@retronym said:
Another example from Akka, as reported in #8673:

tmp$ scala
Welcome to Scala version 2.11.1 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_05).
Type in expressions to have them evaluated.
Type :help for more information.
 
scala> import akka.actor._
import akka.actor._
 
scala> import akka.pattern._
import akka.pattern._
 
scala> import scala.concurrent._
import scala.concurrent._
 
scala> val system = ActorSystem()
system: akka.actor.ActorSystem = akka://default
 
scala> Future.successful("WAT") pipeTo system.deadLetters
<console>:18: error: value pipeTo is not a member of scala.concurrent.Future[String]
              Future.successful("WAT") pipeTo system.deadLetters
                                       ^