Set explicit nulls in CompilationUnitInfo symbols from source

Author: nicolasstucki

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/core/SymbolLoaders.scala

@@ -433,7 +433,7 @@ class TastyLoader(val tastyFile: AbstractFile) extends SymbolLoader {
     new CompilationUnitInfo(
       tastyFile,
       tastyVersion = Some(tastyVersion),
-      tastyExplicitNulls = attributes.explicitNulls,
+      explicitNulls = attributes.explicitNulls,
     )
 
   def description(using Context): String = "TASTy file " + tastyFile.toString

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

@@ -288,6 +288,11 @@ object Symbols {
       if compUnitInfo == null then None
       else compUnitInfo.tastyVersion
 
+    /** If this class has explicit nulls enabled */
+    def explicitNulls(using Context): Boolean =
+      val compUnitInfo = compilationUnitInfo
+      compUnitInfo != null && compUnitInfo.explicitNulls
+
     /** The class file from which this class was generated, null if not applicable. */
     final def binaryFile(using Context): AbstractFile | Null = {
       val file = associatedFile

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 =>