Rename annotation to StableNull and update test

Author: noti0na1

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

@@ -1095,7 +1095,7 @@ class Definitions {
   @tu lazy val RetainsByNameAnnot: ClassSymbol = requiredClass("scala.annotation.retainsByName")
   @tu lazy val PublicInBinaryAnnot: ClassSymbol = requiredClass("scala.annotation.publicInBinary")
   @tu lazy val WitnessNamesAnnot: ClassSymbol = requiredClass("scala.annotation.internal.WitnessNames")
-  @tu lazy val NullTrackableAnnot: ClassSymbol = requiredClass("scala.annotation.nullTrackable")
+  @tu lazy val StableNullAnnot: ClassSymbol = requiredClass("scala.annotation.stableNull")
 
   @tu lazy val JavaRepeatableAnnot: ClassSymbol = requiredClass("java.lang.annotation.Repeatable")
 

compiler/src/dotty/tools/dotc/typer/Nullables.scala

@@ -189,14 +189,14 @@ object Nullables:
   def isTracked(ref: TermRef)(using Context) = // true
     val sym = ref.symbol
 
-    def isNullTrackableField: Boolean =
+    def isNullStableField: Boolean =
       ref.prefix.isStable
       && sym.isField
-      && sym.hasAnnotation(defn.NullTrackableAnnot)
+      && sym.hasAnnotation(defn.StableNullAnnot)
 
     // println(s"isTracked: $ref, usedOutOfOrder = ${ref.usedOutOfOrder}, isStable = ${ref.isStable}, span = ${ref.symbol.span}, assignmentSpans = ${ctx.compilationUnit.assignmentSpans.get(ref.symbol.span.start)}")
     ref.isStable
-    || isNullTrackableField
+    || isNullStableField
     || { val unit = ctx.compilationUnit
          !ref.usedOutOfOrder
          && sym.span.exists

library/src/scala/annotation/nullTrackable.scala renamed to library/src/scala/annotation/stableNull.scala

@@ -7,4 +7,4 @@ package scala.annotation
  *  prefix is a stable path.
  *  See `tests/explicit-nulls/pos/force-track-var-fields.scala` for an example.
  */
-final class nullTrackable extends StaticAnnotation
+private[scala] final class stableNull extends StaticAnnotation

project/Build.scala

@@ -1191,7 +1191,7 @@ object Build {
         file(s"${baseDirectory.value}/src/scala/annotation/init.scala"),
         file(s"${baseDirectory.value}/src/scala/annotation/unroll.scala"),
         file(s"${baseDirectory.value}/src/scala/annotation/targetName.scala"),
-        file(s"${baseDirectory.value}/src/scala/annotation/nullTrackable.scala"),
+        file(s"${baseDirectory.value}/src/scala/annotation/stableNull.scala"),
         file(s"${baseDirectory.value}/src/scala/deriving/Mirror.scala"),
         file(s"${baseDirectory.value}/src/scala/compiletime/package.scala"),
         file(s"${baseDirectory.value}/src/scala/quoted/Type.scala"),
@@ -1327,7 +1327,7 @@ object Build {
         file(s"${baseDirectory.value}/src/scala/annotation/init.scala"),
         file(s"${baseDirectory.value}/src/scala/annotation/unroll.scala"),
         file(s"${baseDirectory.value}/src/scala/annotation/targetName.scala"),
-        file(s"${baseDirectory.value}/src/scala/annotation/nullTrackable.scala"),
+        file(s"${baseDirectory.value}/src/scala/annotation/stableNull.scala"),
         file(s"${baseDirectory.value}/src/scala/deriving/Mirror.scala"),
         file(s"${baseDirectory.value}/src/scala/compiletime/package.scala"),
         file(s"${baseDirectory.value}/src/scala/quoted/Type.scala"),

tests/explicit-nulls/pos/force-track-var-fields.scala

@@ -1,7 +1,9 @@
-import scala.annotation.nullTrackable
+package scala
+
+import scala.annotation.stableNull
 
 class A:
-  @nullTrackable var s: String | Null = null
+  @stableNull var s: String | Null = null
   def getS: String =
     if s == null then s = ""
     s