Require Conversion to be pure

Author: natsukagami

compiler/src/dotty/tools/dotc/core/Definitions.scala

@@ -1148,6 +1148,7 @@ class Definitions {
     "reactor.util.annotation.NonNullApi" ::
     "io.reactivex.annotations.NonNull" :: Nil)
 
+
   // convenient one-parameter method types
   def methOfAny(tp: Type): MethodType = MethodType(List(AnyType), tp)
   def methOfAnyVal(tp: Type): MethodType = MethodType(List(AnyValType), tp)

library/src/scala/Conversion.scala

@@ -25,12 +25,13 @@ import language.experimental.captureChecking
 */
 @java.lang.FunctionalInterface
 abstract class Conversion[-T, +U] extends Function1[T, U]:
-  /** Convert value `x` of type `T` to type `U` */
-  def apply(x: T): U
+  self =>
+    /** Convert value `x` of type `T` to type `U` */
+    def apply(x: T): U
 
-  extension (x: T)
-    /** `x.convert` converts a value `x` of type `T` to type `U` */
-    def convert = this(x)
+    extension (x: T)
+      /** `x.convert` converts a value `x` of type `T` to type `U` */
+      def convert = this(x)
 
 object Conversion:
   import annotation.experimental
@@ -46,5 +47,4 @@ object Conversion:
   /** Unwrap an `into` */
   extension [T](x: into[T])
     @experimental def underlying: T = x
-
-end Conversion
+end Conversion