Re-apply nullable to Option.apply

Author: noti0na1

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

@@ -42,7 +42,7 @@ object NullOpsDecorator:
         }
         if tpStripped ne tpWiden then tpStripped else tp
 
-      if ctx.explicitNulls then strip(self) else self
+      strip(self)
     }
 
     /** Is self (after widening and dealiasing) a type of the form `T | Null`? */

compiler/src/dotty/tools/dotc/transform/GenericSignatures.scala

@@ -304,6 +304,12 @@ object GenericSignatures {
           builder.append(')')
           methodResultSig(rte)
 
+        case OrNull(tp1) if !tp1.derivesFrom(defn.AnyValClass) =>
+          // Special case for nullable union types whose underlying type is not a value class.
+          // For example, `T | Null` where `T` is a type parameter becomes `T` in the signature;
+          // `Int | Null` still becomes `Object`.
+          jsig1(tp1)
+
         case tp: AndType =>
           // Only intersections appearing as the upper-bound of a type parameter
           // can be preserved in generic signatures and those are already
@@ -455,15 +461,15 @@ object GenericSignatures {
       else x
   }
 
-  private def collectMethodParams(mtd: MethodOrPoly)(using Context): (List[TypeParamInfo], List[Type], Type) = 
+  private def collectMethodParams(mtd: MethodOrPoly)(using Context): (List[TypeParamInfo], List[Type], Type) =
     val tparams = ListBuffer.empty[TypeParamInfo]
     val vparams = ListBuffer.empty[Type]
 
     @tailrec def recur(tpe: Type): Type = tpe match
       case mtd: MethodType =>
         vparams ++= mtd.paramInfos.filterNot(_.hasAnnotation(defn.ErasedParamAnnot))
         recur(mtd.resType)
-      case PolyType(tps, tpe) => 
+      case PolyType(tps, tpe) =>
         tparams ++= tps
         recur(tpe)
       case _ =>

library/src/scala/Option.scala

@@ -28,7 +28,7 @@ object Option {
    *  @param  x the value
    *  @return   Some(value) if value != null, None if value == null
    */
-  def apply[A](x: A): Option[A] = if (x == null) None else Some(x)
+  def apply[A](x: A | Null): Option[A] = if (x == null) None else Some(x)
 
   /** An Option factory which returns `None` in a manner consistent with
    *  the collections hierarchy.

library/src/scala/quoted/FromExpr.scala

@@ -104,7 +104,7 @@ object FromExpr {
    */
   given OptionFromExpr[T](using Type[T], FromExpr[T]): FromExpr[Option[T]] with {
     def unapply(x: Expr[Option[T]])(using Quotes) = x match {
-      case '{ Option[T](${Expr(y)}) } => Some(Option(y))
+      case '{ Option[T](${Expr(y)}: T) } => Some(Option(y))
       case '{ None } => Some(None)
       case '{ ${Expr(opt)} : Some[T] } => Some(opt)
       case _ => None

sbt-bridge/src/xsbt/ConsoleInterface.java

@@ -5,7 +5,7 @@
 
 import java.util.ArrayList;
 
-import scala.Some;
+import scala.Option;
 
 import xsbti.Logger;
 
@@ -40,7 +40,7 @@ public void run(
     completeArgsList.add(classpathString);
     String[] completeArgs = completeArgsList.toArray(args);
 
-    ReplDriver driver = new ReplDriver(completeArgs, System.out, Some.apply(loader), ReplDriver.pprintImport());
+    ReplDriver driver = new ReplDriver(completeArgs, System.out, Option.apply(loader), ReplDriver.pprintImport());
 
     State state = driver.initialState();
     assert bindNames.length == bindValues.length;