diff --git a/src/test/scala-2/chiselTests/experimental/hierarchy/DefinitionSpec.scala b/src/test/scala/chiselTests/experimental/hierarchy/DefinitionSpec.scala
similarity index 99%
rename from src/test/scala-2/chiselTests/experimental/hierarchy/DefinitionSpec.scala
rename to src/test/scala/chiselTests/experimental/hierarchy/DefinitionSpec.scala
index 0356b06d5b9..b459b8058d4 100644
--- a/src/test/scala-2/chiselTests/experimental/hierarchy/DefinitionSpec.scala
+++ b/src/test/scala/chiselTests/experimental/hierarchy/DefinitionSpec.scala
@@ -8,6 +8,7 @@ import chisel3.experimental.BaseModule
 import chisel3.experimental.hierarchy.{instantiable, public, Definition, Instance}
 import chisel3.testing.scalatest.FileCheck
 import chiselTests.experimental.ExtensionMethods.ChiselStageHelpers
+import firrtl.annoSeqToSeq
 import circt.stage.ChiselStage
 import org.scalatest.funspec.AnyFunSpec
 import org.scalatest.matchers.should.Matchers
diff --git a/src/test/scala-2/chiselTests/experimental/hierarchy/Examples.scala b/src/test/scala/chiselTests/experimental/hierarchy/Examples.scala
similarity index 94%
rename from src/test/scala-2/chiselTests/experimental/hierarchy/Examples.scala
rename to src/test/scala/chiselTests/experimental/hierarchy/Examples.scala
index 39a5efbc7cd..ca9fb6e5f6e 100644
--- a/src/test/scala-2/chiselTests/experimental/hierarchy/Examples.scala
+++ b/src/test/scala/chiselTests/experimental/hierarchy/Examples.scala
@@ -50,7 +50,7 @@ object Examples {
     out := in + 1.U
   }
   @instantiable
-  class AddOneBlackBox extends ExtModule {
+  class AddOneBlackBox extends ExtModule with IsInstantiable {
     @public val io = FlatIO(new Bundle {
       val in = Input(UInt(32.W))
       val out = Output(UInt(32.W))
@@ -126,7 +126,7 @@ object Examples {
     io.out := io.in
   }
   @instantiable
-  class WireContainer {
+  class WireContainer extends IsInstantiable {
     @public val innerWire = Wire(UInt(32.W))
   }
   @instantiable
@@ -138,7 +138,7 @@ object Examples {
     out := wireContainer.innerWire
   }
   @instantiable
-  class AddOneContainer {
+  class AddOneContainer extends IsInstantiable {
     @public val i0 = Module(new AddOne)
   }
   @instantiable
@@ -150,7 +150,7 @@ object Examples {
     out := moduleContainer.i0.out
   }
   @instantiable
-  class AddOneInstanceContainer {
+  class AddOneInstanceContainer extends IsInstantiable {
     val definition = Definition(new AddOne)
     @public val i0 = Instance(definition)
   }
@@ -163,7 +163,7 @@ object Examples {
     out := instanceContainer.i0.out
   }
   @instantiable
-  class AddOneContainerContainer {
+  class AddOneContainerContainer extends IsInstantiable {
     @public val container = new AddOneContainer
   }
   @instantiable
@@ -175,7 +175,7 @@ object Examples {
     out := containerContainer.container.i0.out
   }
   @instantiable
-  class Viewer(val y: AddTwo, markPlease: Boolean) {
+  class Viewer(val y: AddTwo, markPlease: Boolean) extends IsInstantiable {
     @public val x = y
     if (markPlease) mark(x.i0.innerWire, "first")
   }
@@ -296,14 +296,14 @@ object Examples {
   }
 
   @instantiable
-  class LeafInstantiable(val bundle: Data) {
-    @public val bundle = bundle
+  class LeafInstantiable(val _bundle: Data) extends IsInstantiable {
+    @public val bundle = _bundle
   }
 
   @instantiable
-  class NestedInstantiable(val in: LeafInstantiable, val out: LeafInstantiable) {
-    @public val in = in
-    @public val out = out
+  class NestedInstantiable(val _in: LeafInstantiable, val _out: LeafInstantiable) extends IsInstantiable {
+    @public val in = _in
+    @public val out = _out
   }
 
   @instantiable
@@ -314,7 +314,7 @@ object Examples {
 
     @public val leafOut = new LeafInstantiable(out)
     @public val leafIn = new LeafInstantiable(in)
-    @public val nested = new NestedInstantiable(in = leafIn, out = leafOut)
+    @public val nested = new NestedInstantiable(_in = leafIn, _out = leafOut)
 
   }
   @instantiable
@@ -450,11 +450,11 @@ object Examples {
 
   // For test 9.c in DefinitionSpec - testing .toDefinition on Instance from imported Definition
   @instantiable
-  class BarForImport extends RawModule {
+  class BarForImport extends RawModule with IsInstantiable {
     @public val a = WireInit(false.B)
   }
   @instantiable
-  class FooForImport extends RawModule {
+  class FooForImport extends RawModule with IsInstantiable {
     @public val bar = Module(new BarForImport)
   }
 }
diff --git a/src/test/scala-2/chiselTests/experimental/hierarchy/InstanceSpec.scala b/src/test/scala/chiselTests/experimental/hierarchy/InstanceSpec.scala
similarity index 99%
rename from src/test/scala-2/chiselTests/experimental/hierarchy/InstanceSpec.scala
rename to src/test/scala/chiselTests/experimental/hierarchy/InstanceSpec.scala
index 5fc584c7100..de7f0ecb713 100644
--- a/src/test/scala-2/chiselTests/experimental/hierarchy/InstanceSpec.scala
+++ b/src/test/scala/chiselTests/experimental/hierarchy/InstanceSpec.scala
@@ -10,6 +10,7 @@ import chisel3.testing.scalatest.FileCheck
 import chisel3.util.{DecoupledIO, Valid}
 import chisel3.experimental.{attach, Analog}
 import chisel3.stage.{ChiselGeneratorAnnotation, DesignAnnotation}
+import firrtl.annoSeqToSeq
 import circt.stage.ChiselStage
 import org.scalatest.funspec.AnyFunSpec
 import org.scalatest.matchers.should.Matchers
@@ -639,7 +640,7 @@ class InstanceSpec extends AnyFunSpec with Matchers with Utils with FileCheck {
         @public override val overriddenVal = 12
         @public final val finalVal = 12
         @public lazy val lazyValue = 12
-        @public val value = value
+        @public override val value = value
         @public final override lazy val x: Int = 3
         @public override final lazy val y: Int = 4
       }
@@ -1317,7 +1318,9 @@ class InstanceSpec extends AnyFunSpec with Matchers with Utils with FileCheck {
       }
       ChiselStage.emitCHIRRTL(new Top)
     }
-    it("(9.b): it should not work on inner classes") {
+    // Due to the differences between ClassTag in Scala 3 and TypeTag
+    // in Scala 2, isA should work on inner classes in  Scala 3
+    ignore("(9.b): it should not work on inner classes") {
       class InnerClass extends Module
       class Top extends Module {
         val d = Definition(new InnerClass)
diff --git a/src/test/scala-2/chiselTests/experimental/hierarchy/SeparateElaborationSpec.scala b/src/test/scala/chiselTests/experimental/hierarchy/SeparateElaborationSpec.scala
similarity index 99%
rename from src/test/scala-2/chiselTests/experimental/hierarchy/SeparateElaborationSpec.scala
rename to src/test/scala/chiselTests/experimental/hierarchy/SeparateElaborationSpec.scala
index dbeec0f0298..b408e45a706 100644
--- a/src/test/scala-2/chiselTests/experimental/hierarchy/SeparateElaborationSpec.scala
+++ b/src/test/scala/chiselTests/experimental/hierarchy/SeparateElaborationSpec.scala
@@ -12,7 +12,7 @@ import chisel3.stage.{ChiselCircuitAnnotation, ChiselGeneratorAnnotation, Design
 import chisel3.testing.{FileCheck, HasTestingDirectory}
 import chisel3.testing.scalatest.TestingDirectory
 import circt.stage.{CIRCTTarget, CIRCTTargetAnnotation, ChiselStage}
-import firrtl.AnnotationSeq
+import firrtl.{annoSeqToSeq, seqToAnnoSeq, AnnotationSeq}
 import java.nio.file.Paths
 import org.scalatest.funspec.AnyFunSpec
 import org.scalatest.matchers.should.Matchers