diff --git a/scala3doc-testcases/src/tests/hierarchy.scala b/scala3doc-testcases/src/tests/hierarchy.scala
new file mode 100644
index 000000000000..f7d7119e354c
--- /dev/null
+++ b/scala3doc-testcases/src/tests/hierarchy.scala
@@ -0,0 +1,21 @@
+package tests
+
+package hierarchy
+
+trait A1
+trait A2[T]
+trait A3[A, B]
+
+
+trait B1 extends A1
+trait B2 extends A1 with A2[Int]
+trait B3 extends A2[Int] with A3[Int, String]
+
+class C1[A, B, C] extends B1 with B2 with B3
+
+trait D1
+trait D2[T, R]
+trait D3
+
+class E1 extends C1[Int, String, Boolean] with D1
+class E2 extends C1[Int, Boolean, Any] with D2[Int, Boolean] with D3
diff --git a/scala3doc/src/dotty/dokka/model/api/membersUtils.scala b/scala3doc/src/dotty/dokka/model/api/membersUtils.scala
new file mode 100644
index 000000000000..a780876b106f
--- /dev/null
+++ b/scala3doc/src/dotty/dokka/model/api/membersUtils.scala
@@ -0,0 +1,27 @@
+package dotty.dokka.model.api
+
+import org.jetbrains.dokka.model.DModule
+import scala.jdk.CollectionConverters.{ListHasAsScala, SeqHasAsJava}
+import dotty.dokka.model.api._
+
+extension (m: DModule)
+  def visitMembers(callback: Member => Unit): Unit = 
+    def visitClasslike(c: Member): Unit =
+      callback(c)
+      c.allMembers.foreach(visitClasslike(_))
+    m.getPackages.asScala.foreach(_.allMembers.foreach(visitClasslike(_)))
+
+extension (s: Signature)
+  def getName: String =
+    s.map {
+      case s: String => s
+      case l: Link => l.name
+    }.mkString 
+
+extension (m: Member):
+  def getDirectParentsAsStrings: Seq[String] =
+    m.directParents.map(_.getName).sorted
+  def getParentsAsStrings: Seq[String] =
+    m.parents.map(_.signature.getName).sorted
+  def getKnownChildrenAsStrings: Seq[String] =   
+    m.knownChildren.map(_.signature.getName).sorted
diff --git a/scala3doc/test/dotty/dokka/diagram/HierarchyTest.scala b/scala3doc/test/dotty/dokka/diagram/HierarchyTest.scala
new file mode 100644
index 000000000000..e2b166ddda19
--- /dev/null
+++ b/scala3doc/test/dotty/dokka/diagram/HierarchyTest.scala
@@ -0,0 +1,98 @@
+package dotty.dokka.diagram
+
+import dotty.dokka.ScaladocTest
+import dotty.dokka.Assertion.AfterDocumentablesTransformation
+import dotty.dokka.kUnit
+import dotty.dokka.model.api._
+import scala.jdk.CollectionConverters.{ListHasAsScala, SeqHasAsJava}
+import org.junit.Assert.{assertSame, assertTrue, assertEquals}
+
+class HierarchyTest extends ScaladocTest("hierarchy"):
+  override def assertions = Seq(
+    AfterDocumentablesTransformation { m =>
+      m.visitMembers { x =>
+        if (x.getName == "C1") {
+          assertEquals(List("A1", "A2[Int]", "A3[Int, String]", "Any", "B1", "B2", "B3", "Object"), x.getParentsAsStrings)
+          assertEquals(List("B1", "B2", "B3"), x.getDirectParentsAsStrings)
+          assertEquals(List("E1", "E2"), x.getKnownChildrenAsStrings)
+          val graph = MemberExtension.getFrom(x).map(_.graph)     
+          assertTrue("Graph is empty!", graph.isDefined)
+          assertEquals(
+            Set(
+              "Object" -> "Any",
+              "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[A, B, C]" -> "Object",
+              "C1[A, B, C]" -> "B1",
+              "C1[A, B, C]" -> "B2",
+              "C1[A, B, C]" -> "B3",
+              "E1" -> "C1[A, B, C]",
+              "E2" -> "C1[A, B, C]"
+            ),
+            graph.get.edges.map((a, b) => (a.signature.getName, b.signature.getName)).toSet
+          )
+        }
+        if (x.getName == "E2") {
+          assertEquals(List("A1", "A2[Int]", "A3[Int, String]", "Any", "B1", "B2", "B3", "C1[Int, Boolean, Any]", "D2[Int, Boolean]", "D3", "Object"), x.getParentsAsStrings)
+          assertEquals(List("C1[Int, Boolean, Any]", "D2[Int, Boolean]", "D3"), x.getDirectParentsAsStrings)
+          assertEquals(List.empty, x.getKnownChildrenAsStrings)
+          val graph = MemberExtension.getFrom(x).map(_.graph)   
+          assertTrue("Graph is empty!", graph.isDefined)
+          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",
+              "E2" -> "D2[Int, Boolean]",
+              "E2" -> "D3",
+              "D2[Int, Boolean]" -> "Object",
+              "D3" -> "Object",
+              "E2" -> "C1[Int, Boolean, Any]"
+            ),
+            graph.get.edges.map((a, b) => (a.signature.getName, b.signature.getName)).toSet
+          )
+        }
+        if (x.getName == "A2") {
+          assertEquals(List("Any", "Object"), x.getParentsAsStrings)
+          assertEquals(List.empty, x.getDirectParentsAsStrings)
+          assertEquals(List("B2", "B3", "C1[A, B, C]", "E1", "E2"), x.getKnownChildrenAsStrings)
+          val graph = MemberExtension.getFrom(x).map(_.graph)   
+          assertTrue("Graph is empty!", graph.isDefined)
+          assertEquals(
+            Set(
+              "Object" -> "Any",
+              "A2[T]" -> "Object",
+              "B2" -> "A2[T]", // These are not actually true, becuase we lose information about hierarchy in subtypes and their possible mapping to supertypes other that that type itself, e. g. linking to `Object` 
+              "B3" -> "A2[T]",
+              "C1[A, B, C]" -> "A2[T]",
+              "E1" -> "A2[T]",
+              "E2" -> "A2[T]"
+            ),
+            graph.get.edges.map((a, b) => (a.signature.getName, b.signature.getName)).toSet
+          )
+        }
+      }
+    }
+  )