Add Conversion.into method

Author: odersky

library/src/scala/Conversion.scala

@@ -21,3 +21,6 @@ package scala
 @java.lang.FunctionalInterface
 abstract class Conversion[-T, +U] extends Function1[T, U]:
   def apply(x: T): U
+object Conversion:
+  extension [T](x: T)
+    def into[U](using c: Conversion[T, U]) = c(x)

tests/pos/conversion-into.scala

@@ -0,0 +1,7 @@
+import Conversion.into
+
+given Conversion[String, Int] = _.length
+given Conversion[Int, String] = _.toString
+
+def f(x: String): Int = x.into
+def g(x: Int): String = x.into[String]