Fix #24440: Do not check public flexible types on artifact symbols or inside anonymous classes (#24471)

Fix #24440

Author: noti0na1

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

@@ -1202,8 +1202,9 @@ object RefChecks {
   /** Check that public (and protected) methods/fields do not expose flexible types. */
   def checkPublicFlexibleTypes(sym: Symbol)(using Context): Unit =
     if ctx.explicitNulls && !ctx.isJava
-        && sym.exists && !sym.is(Private) && sym.owner.isClass
-        && !sym.isOneOf(Synthetic | InlineProxy | Param | Exported) then
+        && sym.exists && sym.owner.isClass
+        && !sym.owner.isAnonymousClass
+        && !sym.isOneOf(JavaOrPrivateOrSynthetic | InlineProxy | Param | Exported) then
       val resTp = sym.info.finalResultType
       if resTp.existsPart(_.isInstanceOf[FlexibleType], StopAt.Static) then
         report.warning(

tests/explicit-nulls/pos/i24440.scala

@@ -0,0 +1,17 @@
+//> using options -Yexplicit-nulls -Werror
+
+trait AwtComponentLogging extends java.awt.Component:
+
+  override def getPreferredSize: java.awt.Dimension =
+    val dim: java.awt.Dimension = super.getPreferredSize
+    dim
+
+  private def superPS1 = super.getPreferredSize
+
+  private val superPS2 = super.getPreferredSize
+
+class Test:
+  def getCompoment: java.awt.Component =
+    new java.awt.Component {
+      override def getPreferredSize = super.getPreferredSize
+    }