Fix some inherited members not showing in searchbar in Scaladoc

Allows to search for public members inherited from hidden classlikes
in Scaladoc. Additionally, to avoid confusing users about the missing
link in the "Inherited from:" field, a "(hidden)" adnotation was also
added. A "inheritedMembersFromHidden" Signature Test was also added.

scaladoc-testcases/src/tests/inheritedMembersFromHidden.scala

@@ -0,0 +1,9 @@
+package tests
+package inheritedMembersFromHidden
+
+private[inheritedMembersFromHidden] trait HiddenTrait { //unexpected
+  def method: Unit
+    = ???
+}
+
+object PublicObject extends HiddenTrait //expected: object PublicObject

scaladoc/src/dotty/tools/scaladoc/api.scala

@@ -82,7 +82,7 @@ enum Origin:
 
 case class Overridden(name: String, dri: DRI)
 
-case class InheritedFrom(name: String, dri: DRI)
+case class InheritedFrom(name: String, dri: DRI, isSourceSuperclassHidden: Boolean)
 
 case class Annotation(val dri: DRI, val params: List[Annotation.AnnotationParameter])
 

scaladoc/src/dotty/tools/scaladoc/renderers/MemberRenderer.scala

@@ -29,7 +29,9 @@ class MemberRenderer(signatureRenderer: SignatureRenderer)(using DocContext) ext
     case _ => Nil
 
   def inheritedFrom(m: Member) = m.inheritedFrom match
-    case Some(InheritedFrom(name, dri)) => tableRow("Inherited from:", signatureRenderer.renderLink(name, dri))
+    case Some(InheritedFrom(name, dri, isSourceSuperclassHidden)) =>
+      val hiddenNameSuffix = if isSourceSuperclassHidden then " (hidden)" else "" 
+      tableRow("Inherited from:", signatureRenderer.renderLink(name + hiddenNameSuffix, dri))
     case _ => Nil
 
   def docAttributes(m: Member): Seq[AppliedTag] =

scaladoc/src/dotty/tools/scaladoc/renderers/Resources.scala

@@ -150,7 +150,7 @@ trait Resources(using ctx: DocContext) extends Locations, Writer:
             val entry = mkEntry(member.dri, member.name, flattenToText(sig), descr, member.kind.name)
             val children = member
                 .membersBy(m => m.kind != Kind.Package && !m.kind.isInstanceOf[Classlike])
-                .filter(m => m.origin == Origin.RegularlyDefined && m.inheritedFrom.isEmpty)
+                .filter(m => m.origin == Origin.RegularlyDefined && m.inheritedFrom.fold(false)(_.isSourceSuperclassHidden))
             Seq(entry) ++ children.flatMap(processMember)
 
           processMember(m)

scaladoc/src/dotty/tools/scaladoc/tasty/ClassLikeSupport.scala

@@ -183,7 +183,7 @@ trait ClassLikeSupport:
   }
 
   private def parseInheritedMember(c: ClassDef)(s: Tree): Option[Member] =
-    def inheritance = Some(InheritedFrom(s.symbol.owner.normalizedName, s.symbol.dri))
+    def inheritance = Some(InheritedFrom(s.symbol.owner.normalizedName, s.symbol.dri, s.symbol.owner.isHiddenByVisibility))
     processTreeOpt(s)(s match
       case c: ClassDef if c.symbol.shouldDocumentClasslike => Some(parseClasslike(c, signatureOnly = true))
       case other => {

scaladoc/src/dotty/tools/scaladoc/translators/FilterAttributes.scala

@@ -14,7 +14,7 @@ object FilterAttributes:
     Map("visibility" -> m.visibility.name)
 
   private def inheritedFrom(m: Member): Map[String, String] = m.inheritedFrom match
-    case Some(InheritedFrom(name, _)) => Map("inherited" -> name)
+    case Some(InheritedFrom(name, _, _)) => Map("inherited" -> name)
     case _ => Map.empty
 
   private def origin(m: Member): Map[String, String] = m.origin match

scaladoc/test/dotty/tools/scaladoc/signatures/TranslatableSignaturesTestCases.scala

@@ -58,6 +58,8 @@ class InheritanceLoop extends SignatureTest("inheritanceLoop", SignatureTest.all
 class InheritedMembers extends SignatureTest("inheritedMembers2", SignatureTest.all.filter(_ != "class"),
   sourceFiles = List("inheritedMembers1", "inheritedMembers2"))
 
+class InheritedFromHiddenClasslike extends SignatureTest("inheritedMembersFromHidden", SignatureTest.all)
+
 class ComplexNames extends SignatureTest("complexNames", Seq("def", "class"))
 
 class WrongDocumentationLinks extends SignatureTest("links", Seq("def"))