Make -> sugar an inline method

Must wait for 3.10.0

currently it is transparent inline, to avoid inline proxy objects appearing in capture sets and breaking type checking.

Author: bishabosha

library/src/scala/Predef.scala

@@ -389,7 +389,9 @@ object Predef extends LowPriorityImplicits {
   // implicit classes -----------------------------------------------------
 
   /** @group implicit-classes-any */
+  @deprecated("Use `->` extension method instead.", since = "3.10.0")
   implicit final class ArrowAssoc[A](private val self: A) extends AnyVal {
+    @deprecated("Use `->` extension method instead.", since = "3.10.0")
     @inline def -> [B](y: B): (A, B) = (self, y)
     @deprecated("Use `->` instead. If you still wish to display it as one character, consider using a font with programming ligatures such as Fira Code.", "2.13.0")
     def →[B](y: B): (A, B) = ->(y)
@@ -609,6 +611,11 @@ object Predef extends LowPriorityImplicits {
      */
     inline def runtimeChecked: x.type @RuntimeChecked = x: @RuntimeChecked
 
+  // extension method sugar ---------------------------------------------
+  extension[A] (self: A)
+    transparent inline def -> [B](y: B): (A, B) = (self, y)
+
+
 }
 
 /** The `LowPriorityImplicits` class provides implicit values that