no need to add an x field to everything

however, it must be possible to inline Ensuring, ArrowAssoc methods

renamed the public val x to something a little less intrusive

fixed check file to reflect better error message (see! it wasn't that uncommon for people to write `foo.x` -- NEWS AT ELEVEN)

no review

1 files changed, 13 insertions, 7 deletions

diff --git a/src/library/scala/Predef.scala b/src/library/scala/Predef.scala
index 27197364c9..1d3239a176 100644
--- a/src/library/scala/Predef.scala
+++ b/src/library/scala/Predef.scala
@@ -214,11 +214,14 @@ object Predef extends LowPriorityImplicits {
       throw new IllegalArgumentException("requirement failed: "+ message)
   }
 
-  final class Ensuring[A](val x: A) {
-    def ensuring(cond: Boolean): A = { assert(cond); x }
-    def ensuring(cond: Boolean, msg: => Any): A = { assert(cond, msg); x }
-    def ensuring(cond: A => Boolean): A = { assert(cond(x)); x }
-    def ensuring(cond: A => Boolean, msg: => Any): A = { assert(cond(x), msg); x }
+  final class Ensuring[A](val __resultOfEnsuring: A) { // `__resultOfEnsuring` must be a public val to allow inlining
+    // the val used to be called `x`, but now goes by `__resultOfEnsuring`, as that reduces the chances of a user's writing
+    // `foo.__resultOfEnsuring` and being confused why they get an ambiguous implicit conversion error
+    // (`foo.x` used to produce this error since both any2Ensuring and any2ArrowAssoc pimped an `x` onto everything)
+    def ensuring(cond: Boolean): A = { assert(cond); __resultOfEnsuring }
+    def ensuring(cond: Boolean, msg: => Any): A = { assert(cond, msg); __resultOfEnsuring }
+    def ensuring(cond: A => Boolean): A = { assert(cond(__resultOfEnsuring)); __resultOfEnsuring }
+    def ensuring(cond: A => Boolean, msg: => Any): A = { assert(cond(__resultOfEnsuring), msg); __resultOfEnsuring }
   }
   implicit def any2Ensuring[A](x: A): Ensuring[A] = new Ensuring(x)
 
@@ -241,8 +244,11 @@ object Predef extends LowPriorityImplicits {
     def unapply[A, B, C](x: Tuple3[A, B, C]): Option[Tuple3[A, B, C]] = Some(x)
   }
 
-  final class ArrowAssoc[A](val x: A) {
-    @inline def -> [B](y: B): Tuple2[A, B] = Tuple2(x, y)
+  final class ArrowAssoc[A](val __leftOfArrow: A) {  // `__leftOfArrow` must be a public val to allow inlining
+    // the val used to be called `x`, but now goes by `__leftOfArrow`, as that reduces the chances of a user's writing
+    // `foo.__leftOfArrow` and being confused why they get an ambiguous implicit conversion error
+    // (`foo.x` used to produce this error since both any2Ensuring and any2ArrowAssoc pimped an `x` onto everything)
+    @inline def -> [B](y: B): Tuple2[A, B] = Tuple2(__leftOfArrow, y)
     def →[B](y: B): Tuple2[A, B] = ->(y)
   }
   implicit def any2ArrowAssoc[A](x: A): ArrowAssoc[A] = new ArrowAssoc(x)