Exclude files in dotty package from experimental checks

Author: odersky

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

@@ -445,6 +445,7 @@ object StdNames {
     val derived: N              = "derived"
     val derives: N              = "derives"
     val doubleHash: N           = "doubleHash"
+    val dotty: N                = "dotty"
     val drop: N                 = "drop"
     val dynamics: N             = "dynamics"
     val elem: N                 = "elem"

compiler/src/dotty/tools/dotc/transform/SymUtils.scala

@@ -363,6 +363,8 @@ object SymUtils:
       self.hasAnnotation(defn.ExperimentalAnnot)
       || isDefaultArgumentOfExperimentalMethod
       || (!self.is(Package) && self.owner.isInExperimentalScope)
+      || self.topLevelClass.ownersIterator.exists(p =>
+          p.is(Package) && p.owner.isRoot && p.name == tpnme.dotty)
 
     /** The declared self type of this class, as seen from `site`, stripping
     *  all refinements for opaque types.

tests/pos-custom-args/no-experimental/dotty-experimental.scala

@@ -0,0 +1,6 @@
+package dotty.tools
+object test {
+
+  val x = caps.unsafeBox
+
+}