Only set $c_C.prototype.$classData if C has *direct* instances.

sjrd · sjrd · commit bacbecf6dc76 · 2024-03-16T14:17:06.000+01:00
It is not useful for classes that only have strict sub instances,
i.e., classes that are effectively abstract.
diff --git a/linker/shared/src/main/scala/org/scalajs/linker/backend/emitter/ClassEmitter.scala b/linker/shared/src/main/scala/org/scalajs/linker/backend/emitter/ClassEmitter.scala
@@ -826,7 +826,7 @@ private[emitter] final class ClassEmitter(sjsGen: SJSGen) {
 
   def genTypeData(className: ClassName, kind: ClassKind,
       superClass: Option[ClassIdent], ancestors: List[ClassName],
-      jsNativeLoadSpec: Option[JSNativeLoadSpec], hasInstances: Boolean)(
+      jsNativeLoadSpec: Option[JSNativeLoadSpec], hasDirectInstances: Boolean)(
       implicit moduleContext: ModuleContext,
       globalKnowledge: GlobalKnowledge, pos: Position): WithGlobals[List[js.Tree]] = {
     import TreeDSL._
@@ -847,7 +847,7 @@ private[emitter] final class ClassEmitter(sjsGen: SJSGen) {
     val kindOrCtorParam = {
       if (isJSType) js.IntLiteral(2)
       else if (kind == ClassKind.Interface) js.IntLiteral(1)
-      else if (kind.isClass && hasInstances) globalVar(VarField.c, className)
+      else if (kind.isClass && hasDirectInstances) globalVar(VarField.c, className)
       else js.IntLiteral(0)
     }
 
diff --git a/linker/shared/src/main/scala/org/scalajs/linker/backend/emitter/Emitter.scala b/linker/shared/src/main/scala/org/scalajs/linker/backend/emitter/Emitter.scala
@@ -716,14 +716,14 @@ final class Emitter[E >: Null <: js.Tree](
 
       if (linkedClass.hasRuntimeTypeInfo) {
         main ++= extractWithGlobals(classTreeCache.typeData.getOrElseUpdate(
-            linkedClass.hasInstances,
+            linkedClass.hasDirectInstances,
             classEmitter.genTypeData(
               className, // invalidated by overall class cache (part of ancestors)
               kind, // invalidated by class version
               linkedClass.superClass, // invalidated by class version
               linkedClass.ancestors, // invalidated by overall class cache (identity)
               linkedClass.jsNativeLoadSpec, // invalidated by class version
-              linkedClass.hasInstances // invalidated directly (it is the input to `getOrElseUpdate`)
+              linkedClass.hasDirectInstances // invalidated directly (it is the input to `getOrElseUpdate`)
             )(moduleContext, classCache, linkedClass.pos).map(postTransform(_, 0))))
       }
     }
