Set explicit nulls in CompilationUnitInfo symbols from source

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

@@ -9,23 +9,23 @@ import dotty.tools.tasty.TastyVersion
   *                       the class containing this symbol was generated,
   *                       null if not applicable.
   * @param tastyVersion   The TASTy version (major, minor, experimental)
-  * @param tastyExplicitNulls  Was this compilation unit compiled with explicit nulls?
+  * @param explicitNulls  This compilation unit has explicit nulls enabled?
   */
 class CompilationUnitInfo(
   val associatedFile: AbstractFile,
   val tastyVersion: Option[TastyVersion],
-  val tastyExplicitNulls: Boolean
+  val explicitNulls: Boolean
 ) {
 
   override def toString(): String =
     s"CompilationUnitInfo($associatedFile, $tastyVersion)"
 }
 
 object CompilationUnitInfo:
-  def apply(assocFile: AbstractFile | Null): CompilationUnitInfo | Null =
+  def apply(assocFile: AbstractFile | Null, explicitNulls: Boolean = false): CompilationUnitInfo | Null =
     if assocFile == null then null
     else new CompilationUnitInfo(
       assocFile,
       tastyVersion = None,
-      tastyExplicitNulls = false // TODO track explicit nulls for current compilation units (not only TASTy)
+      explicitNulls = explicitNulls,
     )

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

@@ -250,7 +250,7 @@ class Namer { typer: Typer =>
         val cls =
           createOrRefine[ClassSymbol](tree, name, flags, ctx.owner,
             cls => adjustIfModule(new ClassCompleter(cls, tree)(ctx), tree),
-            newClassSymbol(ctx.owner, name, _, _, _, tree.nameSpan, CompilationUnitInfo(ctx.source.file)))
+            newClassSymbol(ctx.owner, name, _, _, _, tree.nameSpan, CompilationUnitInfo(ctx.source.file, explicitNulls = ctx.explicitNulls)))
         cls.completer.asInstanceOf[ClassCompleter].init()
         cls
       case tree: MemberDef =>