Also check definitions inside package objects

Author: odersky

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

@@ -727,15 +727,20 @@ object Checking {
  * all statements are @experimental definitions.
  */
  def checkExperimentalImports(trees: List[Tree])(using Context): Unit =
- def onlyExperimentalDefs = trees.forall {
- case _: Import | EmptyTree => true
- case stat: MemberDef => stat.symbol.isExperimental || stat.symbol.is(Synthetic)
- case _ => false
+ def onlyExperimentalDefs(trees: List[Tree]): Boolean = trees.forall {
+ case _: Import | EmptyTree =>
+ true
+ case tree @ TypeDef(_, impl: Template) if tree.symbol.isPackageObject =>
+ onlyExperimentalDefs(impl.body)
+ case stat: MemberDef =>
+ stat.symbol.isExperimental || stat.symbol.is(Synthetic)
+ case _ =>
+ false
  }
  for case imp @ Import(qual, selectors) <- trees do
  languageImport(qual) match
  case Some(nme.experimental)
- if !ctx.owner.isInExperimentalScope && !onlyExperimentalDefs
+ if !ctx.owner.isInExperimentalScope && !onlyExperimentalDefs(trees)
  && selectors.exists(sel => Feature.experimental(sel.name) != Feature.scala2macros) =>
  Feature.checkExperimentalFeature("features", imp.srcPos)
  case _ =>