diff --git a/src/tests.ts b/src/tests.ts
index b0abcf5..51fd74c 100644
--- a/src/tests.ts
+++ b/src/tests.ts
@@ -1,5 +1,6 @@
 import { Simplify } from "type-fest"
-import { TraitImplInstance, expresses, trait } from "."
+import { TraitAbstractMembers, TraitImplInstance, expresses, trait } from "."
+import { MergeInheritanceTree, TraitsAbstractMembers } from "./util"
 
 
 const PrintsHelloOnNew = trait()(Super =>
@@ -22,11 +23,16 @@ const Identifiable = <ID>() => (
 )
 
 
-type Test = Simplify<TraitImplInstance<ReturnType<typeof Identifiable<bigint>>>>
+// type Test = Simplify<TraitImplInstance<ReturnType<typeof Identifiable<bigint>>>>
+type Test1 = [
+    TraitAbstractMembers<ReturnType<typeof Identifiable<bigint>>>,
+    TraitAbstractMembers<ReturnType<typeof Identifiable<bigint>>>
+]
+type Test2 = MergeInheritanceTree<Test1>
 
 const appliedIdentifiable = Identifiable<bigint>().apply({} as any)
 
-const exp = expresses(Identifiable<bigint>())
+const exp = expresses(Identifiable<bigint>(), Identifiable<number>())
 
 class User implements ReturnType<typeof exp.implements> {
     id: bigint = -1n