Make parameters to implicit value classes private

So that they aren't offered as an autocomplete suggestion:

    implicit class Shouty(string: String) extends AnyVal {
      def SHOUT_! = string.toUpperCase + "!"
    }
    "". // autocompletion offers `.string` here

The original incarnation of value classes didn't allow this
sort of encapsulation, so we either invented goofy names like
`__thingToAdd` or just picked `x` or `self`. But SI-7859 has
delivered us the freedom to keep the accessor private.

Should we keep any of these accessors around in a deprecated
form?

The implicit classes in Predef were added in 2.11.0-M2
(c26a8db067e4f), so they are okay.

I think we can make reason that these APIs were both accidental
and unlikely to be interpreted as public, so we can break them
immediately.

    scala> Left(1).x
    res0: scala.util.Either[Int,Int] = Left(1)

    scala> import concurrent.duration._
    import concurrent.duration._

    scala> 1.n
    res1: Int = 1

9 files changed, 17 insertions, 77 deletions

diff --git a/test/files/neg/logImplicits.check b/test/files/neg/logImplicits.check
index 0522bd8354..2265614962 100644
--- a/test/files/neg/logImplicits.check
+++ b/test/files/neg/logImplicits.check
@@ -7,10 +7,10 @@ logImplicits.scala:7: applied implicit conversion from String("abc") to ?{def ma
 logImplicits.scala:15: inferred view from String("abc") to Int = C.this.convert:(p: String("abc"))Int
   math.max(122, x: Int)
                 ^
-logImplicits.scala:19: applied implicit conversion from Int(1) to ?{def ->: ?} = implicit def ArrowAssoc[A](__leftOfArrow: A): ArrowAssoc[A]
+logImplicits.scala:19: applied implicit conversion from Int(1) to ?{def ->: ?} = implicit def ArrowAssoc[A](self: A): ArrowAssoc[A]
   def f = (1 -> 2) + "c"
            ^
-logImplicits.scala:19: applied implicit conversion from (Int, Int) to ?{def +: ?} = implicit def StringAdd[A](__thingToAdd: A): StringAdd[A]
+logImplicits.scala:19: applied implicit conversion from (Int, Int) to ?{def +: ?} = implicit def StringAdd[A](self: A): StringAdd[A]
   def f = (1 -> 2) + "c"
              ^
 logImplicits.scala:22: error: class Un needs to be abstract, since method unimplemented is not defined
diff --git a/test/files/presentation/callcc-interpreter.check b/test/files/presentation/callcc-interpreter.check
index 59c841a255..d41b982614 100644
--- a/test/files/presentation/callcc-interpreter.check
+++ b/test/files/presentation/callcc-interpreter.check
@@ -3,7 +3,7 @@ reload: CallccInterpreter.scala
 askTypeCompletion at CallccInterpreter.scala(51,38)
 ================================================================================
 [response] askCompletionAt (51,38)
-retrieved 63 members
+retrieved 59 members
 abstract trait Term extends AnyRef
 abstract trait Value extends AnyRef
 case class Add extends callccInterpreter.Term with Product with Serializable
@@ -52,10 +52,6 @@ final def synchronized[T0](x$1: T0): T0
 final def wait(): Unit
 final def wait(x$1: Long): Unit
 final def wait(x$1: Long,x$2: Int): Unit
-private[this] val __leftOfArrow: callccInterpreter.type
-private[this] val __resultOfEnsuring: callccInterpreter.type
-private[this] val __stringToFormat: callccInterpreter.type
-private[this] val __thingToAdd: callccInterpreter.type
 private[this] val term0: callccInterpreter.App
 private[this] val term1: callccInterpreter.App
 private[this] val term2: callccInterpreter.Add
diff --git a/test/files/presentation/ide-bug-1000349.check b/test/files/presentation/ide-bug-1000349.check
index b15486f4ac..aa6660cec5 100644
--- a/test/files/presentation/ide-bug-1000349.check
+++ b/test/files/presentation/ide-bug-1000349.check
@@ -3,7 +3,7 @@ reload: CompletionOnEmptyArgMethod.scala
 askTypeCompletion at CompletionOnEmptyArgMethod.scala(2,17)
 ================================================================================
 [response] askCompletionAt (2,17)
-retrieved 36 members
+retrieved 32 members
 def +(other: String): String
 def ->[B](y: B): (Foo, B)
 def ensuring(cond: Boolean): Foo
@@ -31,10 +31,6 @@ final def synchronized[T0](x$1: T0): T0
 final def wait(): Unit
 final def wait(x$1: Long): Unit
 final def wait(x$1: Long,x$2: Int): Unit
-private[this] val __leftOfArrow: Foo
-private[this] val __resultOfEnsuring: Foo
-private[this] val __stringToFormat: Foo
-private[this] val __thingToAdd: Foo
 protected[package lang] def clone(): Object
 protected[package lang] def finalize(): Unit
 ================================================================================
diff --git a/test/files/presentation/ide-bug-1000475.check b/test/files/presentation/ide-bug-1000475.check
index e4b8508846..cb7de6d34a 100644
--- a/test/files/presentation/ide-bug-1000475.check
+++ b/test/files/presentation/ide-bug-1000475.check
@@ -3,7 +3,7 @@ reload: Foo.scala
 askTypeCompletion at Foo.scala(3,7)
 ================================================================================
 [response] askCompletionAt (3,7)
-retrieved 35 members
+retrieved 31 members
 [inaccessible] protected[package lang] def clone(): Object
 [inaccessible] protected[package lang] def finalize(): Unit
 def +(other: String): String
@@ -32,16 +32,12 @@ final def synchronized[T0](x$1: T0): T0
 final def wait(): Unit
 final def wait(x$1: Long): Unit
 final def wait(x$1: Long,x$2: Int): Unit
-private[this] val __leftOfArrow: Object
-private[this] val __resultOfEnsuring: Object
-private[this] val __stringToFormat: Object
-private[this] val __thingToAdd: Object
 ================================================================================
 
 askTypeCompletion at Foo.scala(6,10)
 ================================================================================
 [response] askCompletionAt (6,10)
-retrieved 35 members
+retrieved 31 members
 [inaccessible] protected[package lang] def clone(): Object
 [inaccessible] protected[package lang] def finalize(): Unit
 def +(other: String): String
@@ -70,16 +66,12 @@ final def synchronized[T0](x$1: T0): T0
 final def wait(): Unit
 final def wait(x$1: Long): Unit
 final def wait(x$1: Long,x$2: Int): Unit
-private[this] val __leftOfArrow: Object
-private[this] val __resultOfEnsuring: Object
-private[this] val __stringToFormat: Object
-private[this] val __thingToAdd: Object
 ================================================================================
 
 askTypeCompletion at Foo.scala(7,7)
 ================================================================================
 [response] askCompletionAt (7,7)
-retrieved 35 members
+retrieved 31 members
 [inaccessible] protected[package lang] def clone(): Object
 [inaccessible] protected[package lang] def finalize(): Unit
 def +(other: String): String
@@ -108,8 +100,4 @@ final def synchronized[T0](x$1: T0): T0
 final def wait(): Unit
 final def wait(x$1: Long): Unit
 final def wait(x$1: Long,x$2: Int): Unit
-private[this] val __leftOfArrow: Object
-private[this] val __resultOfEnsuring: Object
-private[this] val __stringToFormat: Object
-private[this] val __thingToAdd: Object
 ================================================================================
diff --git a/test/files/presentation/ide-bug-1000531.check b/test/files/presentation/ide-bug-1000531.check
index be8805330a..9a2cad5fd2 100644
--- a/test/files/presentation/ide-bug-1000531.check
+++ b/test/files/presentation/ide-bug-1000531.check
@@ -3,7 +3,7 @@ reload: CrashOnLoad.scala
 askTypeCompletion at CrashOnLoad.scala(6,12)
 ================================================================================
 [response] askCompletionAt (6,12)
-retrieved 124 members
+retrieved 120 members
 [inaccessible] protected[package lang] def clone(): Object
 [inaccessible] protected[package lang] def finalize(): Unit
 [inaccessible] protected[this] def reversed: List[B]
@@ -121,8 +121,4 @@ final def synchronized[T0](x$1: T0): T0
 final def wait(): Unit
 final def wait(x$1: Long): Unit
 final def wait(x$1: Long,x$2: Int): Unit
-private[this] val __leftOfArrow: java.util.Iterator[B]
-private[this] val __resultOfEnsuring: java.util.Iterator[B]
-private[this] val __stringToFormat: java.util.Iterator[B]
-private[this] val __thingToAdd: java.util.Iterator[B]
 ================================================================================
diff --git a/test/files/presentation/implicit-member.check b/test/files/presentation/implicit-member.check
index acf7e1a0fd..ef361599c5 100644
--- a/test/files/presentation/implicit-member.check
+++ b/test/files/presentation/implicit-member.check
@@ -3,7 +3,7 @@ reload: ImplicitMember.scala
 askTypeCompletion at ImplicitMember.scala(7,7)
 ================================================================================
 [response] askCompletionAt (7,7)
-retrieved 38 members
+retrieved 34 members
 def +(other: String): String
 def ->[B](y: B): (Implicit.type, B)
 def ensuring(cond: Boolean): Implicit.type
@@ -32,10 +32,6 @@ final def wait(): Unit
 final def wait(x$1: Long): Unit
 final def wait(x$1: Long,x$2: Int): Unit
 implicit def AppliedImplicit[A](x: A): Implicit.AppliedImplicit[A]
-private[this] val __leftOfArrow: Implicit.type
-private[this] val __resultOfEnsuring: Implicit.type
-private[this] val __stringToFormat: Implicit.type
-private[this] val __thingToAdd: Implicit.type
 private[this] val x: Implicit.type
 protected[package lang] def clone(): Object
 protected[package lang] def finalize(): Unit
diff --git a/test/files/presentation/ping-pong.check b/test/files/presentation/ping-pong.check
index be80601e11..10d29bfed6 100644
--- a/test/files/presentation/ping-pong.check
+++ b/test/files/presentation/ping-pong.check
@@ -3,7 +3,7 @@ reload: PingPong.scala
 askTypeCompletion at PingPong.scala(10,23)
 ================================================================================
 [response] askCompletionAt (10,23)
-retrieved 39 members
+retrieved 35 members
 [inaccessible] private[this] val ping: Ping
 [inaccessible] protected[package lang] def clone(): Object
 [inaccessible] protected[package lang] def finalize(): Unit
@@ -34,17 +34,13 @@ final def wait(): Unit
 final def wait(x$1: Long): Unit
 final def wait(x$1: Long,x$2: Int): Unit
 override def toString(): String
-private[this] val __leftOfArrow: Pong
-private[this] val __resultOfEnsuring: Pong
-private[this] val __stringToFormat: Pong
-private[this] val __thingToAdd: Pong
 private[this] val name: String
 ================================================================================
 
 askTypeCompletion at PingPong.scala(19,20)
 ================================================================================
 [response] askCompletionAt (19,20)
-retrieved 39 members
+retrieved 35 members
 [inaccessible] protected[package lang] def clone(): Object
 [inaccessible] protected[package lang] def finalize(): Unit
 def +(other: String): String
@@ -76,10 +72,6 @@ final def wait(): Unit
 final def wait(x$1: Long): Unit
 final def wait(x$1: Long,x$2: Int): Unit
 override def toString(): String
-private[this] val __leftOfArrow: Ping
-private[this] val __resultOfEnsuring: Ping
-private[this] val __stringToFormat: Ping
-private[this] val __thingToAdd: Ping
 private[this] val pong: Pong
 ================================================================================
 
diff --git a/test/files/presentation/t5708.check b/test/files/presentation/t5708.check
index b2cedd689f..5f17c0b762 100644
--- a/test/files/presentation/t5708.check
+++ b/test/files/presentation/t5708.check
@@ -3,7 +3,7 @@ reload: Completions.scala
 askTypeCompletion at Completions.scala(17,9)
 ================================================================================
 [response] askCompletionAt (17,9)
-retrieved 43 members
+retrieved 39 members
 [inaccessible] private def privateM: String
 [inaccessible] private[this] val privateV: String
 [inaccessible] private[this] val protectedV: String
@@ -39,9 +39,5 @@ final def wait(x$1: Long,x$2: Int): Unit
 final private[this] val CONST_STRING: String("constant")
 lazy private[this] var foo: Int
 private[package test] def pkgPrivateM: String
-private[this] val __leftOfArrow: test.Compat.type
-private[this] val __resultOfEnsuring: test.Compat.type
-private[this] val __stringToFormat: test.Compat.type
-private[this] val __thingToAdd: test.Compat.type
 private[this] val pkgPrivateV: String
 ================================================================================
diff --git a/test/files/presentation/visibility.check b/test/files/presentation/visibility.check
index 4ba7dbaad9..078e0a2342 100644
--- a/test/files/presentation/visibility.check
+++ b/test/files/presentation/visibility.check
@@ -3,7 +3,7 @@ reload: Completions.scala
 askTypeCompletion at Completions.scala(14,12)
 ================================================================================
 [response] askCompletionAt (14,12)
-retrieved 41 members
+retrieved 37 members
 [inaccessible] private[this] def secretPrivateThis(): Unit
 def +(other: String): String
 def ->[B](y: B): (accessibility.Foo, B)
@@ -34,10 +34,6 @@ final def wait(): Unit
 final def wait(x$1: Long): Unit
 final def wait(x$1: Long,x$2: Int): Unit
 private def secretPrivate(): Unit
-private[this] val __leftOfArrow: accessibility.Foo
-private[this] val __resultOfEnsuring: accessibility.Foo
-private[this] val __stringToFormat: accessibility.Foo
-private[this] val __thingToAdd: accessibility.Foo
 protected def secretProtected(): Unit
 protected[package accessibility] def secretProtectedInPackage(): Unit
 protected[package lang] def clone(): Object
@@ -47,7 +43,7 @@ protected[package lang] def finalize(): Unit
 askTypeCompletion at Completions.scala(16,11)
 ================================================================================
 [response] askCompletionAt (16,11)
-retrieved 41 members
+retrieved 37 members
 def +(other: String): String
 def ->[B](y: B): (accessibility.Foo, B)
 def ensuring(cond: Boolean): accessibility.Foo
@@ -78,10 +74,6 @@ final def wait(x$1: Long): Unit
 final def wait(x$1: Long,x$2: Int): Unit
 private def secretPrivate(): Unit
 private[this] def secretPrivateThis(): Unit
-private[this] val __leftOfArrow: accessibility.Foo
-private[this] val __resultOfEnsuring: accessibility.Foo
-private[this] val __stringToFormat: accessibility.Foo
-private[this] val __thingToAdd: accessibility.Foo
 protected def secretProtected(): Unit
 protected[package accessibility] def secretProtectedInPackage(): Unit
 protected[package lang] def clone(): Object
@@ -91,7 +83,7 @@ protected[package lang] def finalize(): Unit
 askTypeCompletion at Completions.scala(22,11)
 ================================================================================
 [response] askCompletionAt (22,11)
-retrieved 41 members
+retrieved 37 members
 [inaccessible] private def secretPrivate(): Unit
 def +(other: String): String
 def ->[B](y: B): (accessibility.AccessibilityChecks, B)
@@ -122,10 +114,6 @@ final def synchronized[T0](x$1: T0): T0
 final def wait(): Unit
 final def wait(x$1: Long): Unit
 final def wait(x$1: Long,x$2: Int): Unit
-private[this] val __leftOfArrow: accessibility.AccessibilityChecks
-private[this] val __resultOfEnsuring: accessibility.AccessibilityChecks
-private[this] val __stringToFormat: accessibility.AccessibilityChecks
-private[this] val __thingToAdd: accessibility.AccessibilityChecks
 protected def secretProtected(): Unit
 protected[package accessibility] def secretProtectedInPackage(): Unit
 protected[package lang] def clone(): Object
@@ -135,7 +123,7 @@ protected[package lang] def finalize(): Unit
 askTypeCompletion at Completions.scala(28,10)
 ================================================================================
 [response] askCompletionAt (28,10)
-retrieved 41 members
+retrieved 37 members
 [inaccessible] private def secretPrivate(): Unit
 [inaccessible] private[this] def secretPrivateThis(): Unit
 [inaccessible] protected def secretProtected(): Unit
@@ -169,17 +157,13 @@ final def synchronized[T0](x$1: T0): T0
 final def wait(): Unit
 final def wait(x$1: Long): Unit
 final def wait(x$1: Long,x$2: Int): Unit
-private[this] val __leftOfArrow: accessibility.Foo
-private[this] val __resultOfEnsuring: accessibility.Foo
-private[this] val __stringToFormat: accessibility.Foo
-private[this] val __thingToAdd: accessibility.Foo
 protected[package accessibility] def secretProtectedInPackage(): Unit
 ================================================================================
 
 askTypeCompletion at Completions.scala(37,8)
 ================================================================================
 [response] askCompletionAt (37,8)
-retrieved 41 members
+retrieved 37 members
 [inaccessible] private def secretPrivate(): Unit
 [inaccessible] private[this] def secretPrivateThis(): Unit
 [inaccessible] protected def secretProtected(): Unit
@@ -214,8 +198,4 @@ final def synchronized[T0](x$1: T0): T0
 final def wait(): Unit
 final def wait(x$1: Long): Unit
 final def wait(x$1: Long,x$2: Int): Unit
-private[this] val __leftOfArrow: accessibility.Foo
-private[this] val __resultOfEnsuring: accessibility.Foo
-private[this] val __stringToFormat: accessibility.Foo
-private[this] val __thingToAdd: accessibility.Foo
 ================================================================================