Merge pull request #11123 from BarkingBad/scala3doc/typedef-defdef-issues

Fix cast exception while traversing supertypes in Scala3doc

Author: BarkingBad

scala3doc-testcases/src/tests/fieldsSignatures.scala

@@ -38,4 +38,4 @@ object Documentation
 {
   val valInsideDocObject: Nothing
     = ???
-}
+}

scala3doc/src/dotty/dokka/tasty/ClassLikeSupport.scala

@@ -61,20 +61,23 @@ trait ClassLikeSupport:
     modifiers: Seq[Modifier] = classDef.symbol.getExtraModifiers(),
   ): Member =
 
-    // This Try is here because of problem that code compiles, but at runtime fails claiming
-    // java.lang.ClassCastException: class dotty.tools.dotc.ast.Trees$DefDef cannot be cast to class dotty.tools.dotc.ast.Trees$TypeDef (dotty.tools.dotc.ast.Trees$DefDef and dotty.tools.dotc.ast.Trees$TypeDef are in unnamed module of loader 'app')
-    // It is probably bug in Tasty
-    def hackGetParents(classDef: ClassDef): Option[List[Tree]] = scala.util.Try(classDef.parents).toOption
-
-    def getSupertypesGraph(classDef: ClassDef, link: LinkToType): Seq[(LinkToType, LinkToType)] =
+    def unpackTreeToClassDef(tree: Tree): ClassDef = tree match
+      case tree: ClassDef => tree
+      case TypeDef(_, tbt: TypeBoundsTree) => unpackTreeToClassDef(tbt.tpe.typeSymbol.tree)
+      case TypeDef(_, tt: TypeTree) => unpackTreeToClassDef(tt.tpe.typeSymbol.tree)
+      case c: Apply =>
+        c.symbol.owner.tree.symbol.tree match
+          case tree: ClassDef => tree
+      case tt: TypeTree => unpackTreeToClassDef(tt.tpe.typeSymbol.tree)
+
+    def getSupertypesGraph(classDef: Tree, link: LinkToType): Seq[(LinkToType, LinkToType)] =
       val smbl = classDef.symbol
-      val parents = if smbl.exists then hackGetParents(smbl.tree.asInstanceOf[ClassDef]) else None
-      parents.fold(Seq())(_.flatMap { case tree =>
-          val symbol = if tree.symbol.isClassConstructor then tree.symbol.owner else tree.symbol
-          val superLink = LinkToType(tree.dokkaType.asSignature, symbol.dri, bareClasslikeKind(symbol))
-          Seq(link -> superLink) ++ getSupertypesGraph(tree.asInstanceOf[ClassDef], superLink)
-        }
-      )
+      val parents = unpackTreeToClassDef(classDef).parents
+      parents.flatMap { case tree =>
+        val symbol = if tree.symbol.isClassConstructor then tree.symbol.owner else tree.symbol
+        val superLink = LinkToType(tree.dokkaType.asSignature, symbol.dri, bareClasslikeKind(symbol))
+        Seq(link -> superLink) ++ getSupertypesGraph(tree, superLink)
+      }
 
     val supertypes = getSupertypes(using qctx)(classDef).map {
       case (symbol, tpe) =>

scala3doc/test/dotty/dokka/diagram/HierarchyTest.scala

@@ -52,21 +52,21 @@ class HierarchyTest extends ScaladocTest("hierarchy"):
           assertEquals(
             Set(
               "Object" -> "Any",
-              // "A1" -> "Object", // These are not applicable beacuase of bug and its workaround
-              // "A2[Int]" -> "Object", // More info at ClassLikeSupport.scala:37
-              // "A3[Int, String]" -> "Object",
-              // "B1" -> "Object",
-              // "B1" -> "A1",
-              // "B2" -> "Object",
-              // "B2" -> "A1",
-              // "B2" -> "A2[Int]",
-              // "B3" -> "Object",
-              // "B3" -> "A2[Int]",
-              // "B3" -> "A3[Int, String]",
-              // "C1[Int, Boolean, Any]" -> "Object",
-              // "C1[Int, Boolean, Any]" -> "B1",
-              // "C1[Int, Boolean, Any]" -> "B2",
-              // "C1[Int, Boolean, Any]" -> "B3",
+              "A1" -> "Object",
+              "A2[Int]" -> "Object",
+              "A3[Int, String]" -> "Object",
+              "B1" -> "Object",
+              "B1" -> "A1",
+              "B2" -> "Object",
+              "B2" -> "A1",
+              "B2" -> "A2[Int]",
+              "B3" -> "Object",
+              "B3" -> "A2[Int]",
+              "B3" -> "A3[Int, String]",
+              "C1[Int, Boolean, Any]" -> "Object",
+              "C1[Int, Boolean, Any]" -> "B1",
+              "C1[Int, Boolean, Any]" -> "B2",
+              "C1[Int, Boolean, Any]" -> "B3",
               "Object" -> "Matchable",
               "Matchable" -> "Any",
               "E2" -> "D2[Int, Boolean]",