Mark UnsafeJavaReturn as experimental

Author: noti0na1

compiler/src/dotty/tools/dotc/Run.scala

@@ -368,7 +368,7 @@ class Run(comp: Compiler, ictx: Context) extends ImplicitRunInfo with Constraint
     if ctx.settings.YexplicitNulls.value then
       if !Feature.enabledBySetting(nme.unsafeNulls) then
         start = start.addMode(Mode.SafeNulls)
-      if Feature.enabledBySetting(nme.unsafeJavaReturn) then
+      if Feature.enabledBySetting(Feature.unsafeJavaReturn) then
         start = start.addMode(Mode.UnsafeJavaReturn)
     ctx.initialize()(using start) // re-initialize the base context with start
 

compiler/src/dotty/tools/dotc/config/Feature.scala

@@ -28,6 +28,7 @@ object Feature:
   val symbolLiterals = deprecated("symbolLiterals")
   val fewerBraces = experimental("fewerBraces")
   val saferExceptions = experimental("saferExceptions")
+  val unsafeJavaReturn = experimental("unsafeJavaReturn")
 
   /** Is `feature` enabled by by a command-line setting? The enabling setting is
    *

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

@@ -26,6 +26,7 @@ import scala.io.Codec
 import collection.mutable
 import printing._
 import config.{JavaPlatform, SJSPlatform, Platform, ScalaSettings}
+import config.Feature
 import classfile.ReusableDataReader
 import StdNames.nme
 
@@ -649,7 +650,7 @@ object Contexts {
           case Some(false)  =>
             setMode(this.mode | Mode.SafeNulls)
           case _ =>
-        importInfo.mentionsFeature(nme.unsafeJavaReturn) match
+        importInfo.mentionsFeature(Feature.unsafeJavaReturn) match
           case Some(true) =>
             setMode(this.mode | Mode.UnsafeJavaReturn)
           case Some(false) =>

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

@@ -612,7 +612,6 @@ object StdNames {
     val unapplySeq: N           = "unapplySeq"
     val unbox: N                = "unbox"
     val universe: N             = "universe"
-    val unsafeJavaReturn: N     = "unsafeJavaReturn"
     val unsafeNulls: N          = "unsafeNulls"
     val update: N               = "update"
     val updateDynamic: N        = "updateDynamic"

library/src/scala/annotation/CanEqualNull.scala

@@ -18,4 +18,5 @@ package scala.annotation
  *  ss.map(_ == null)
  *  ```
  */
+@experimental
 final class CanEqualNull extends RefiningAnnotation

library/src/scala/runtime/stdLibPatches/language.scala

@@ -60,6 +60,11 @@ object language:
     @compileTimeOnly("`saferExceptions` can only be used at compile time in import statements")
     object saferExceptions
 
+    /** Experimental support for unsafe Java return in explicit nulls
+     */
+    @compileTimeOnly("`unsafeJavaReturn` can only be used at compile time in import statements")
+    object unsafeJavaReturn
+
   end experimental
 
   /** The deprecated object contains features that are no longer officially suypported in Scala.
@@ -128,9 +133,6 @@ object language:
   @compileTimeOnly("`unsafeNulls` can only be used at compile time in import statements")
   object unsafeNulls
 
-  @compileTimeOnly("`unsafeJavaReturn` can only be used at compile time in import statements")
-  object unsafeJavaReturn
-
   @compileTimeOnly("`future` can only be used at compile time in import statements")
   object future
 

tests/explicit-nulls/unsafe-java/JavaStatic.scala

@@ -1,4 +1,4 @@
-import language.unsafeJavaReturn
+import language.experimental.unsafeJavaReturn
 
 import java.math.MathContext, MathContext._
 

tests/explicit-nulls/unsafe-java/UnaryCall.scala

@@ -1,4 +1,4 @@
-import scala.language.unsafeJavaReturn
+import scala.language.experimental.unsafeJavaReturn
 
 import java.lang.reflect.Method
 

tests/explicit-nulls/unsafe-java/java-chain/S.scala

@@ -1,4 +1,4 @@
-import scala.language.unsafeJavaReturn
+import scala.language.experimental.unsafeJavaReturn
 
 def f = {
   val j: J2 = new J2()

tests/explicit-nulls/unsafe-java/java-class/S.scala

@@ -1,4 +1,4 @@
-import scala.language.unsafeJavaReturn
+import scala.language.experimental.unsafeJavaReturn
 
 import scala.annotation.CanEqualNull
 import java.{util => ju}