rollup.config.ts

@@ -6,7 +6,7 @@ import pkg from "./package.json" assert { type: "json" }
 
 
 export default defineConfig({
-    input: "src/index.ts",
+    input: "src/lib.ts",
 
     output: [
         {

src/TraitExpression.ts

@@ -1,7 +1,14 @@
 import { Call, Fn, Pipe, Tuples } from "hotscript"
-import { AbstractClass, Class, Opaque, Simplify } from "type-fest"
+import { AbstractClass, Class, Opaque } from "type-fest"
 import { AbstractTag, RemoveAbstractFromImplClass, Trait, TraitApplierSuperTag } from "."
-import { CommonKeys, ExtendFn, KeysOnlyInLeft, SimplifyFn, StaticMembersFn } from "./util"
+import { ExtendFn, SimplifyFn, StaticMembersFn } from "./util"
+
+
+type RemoveSupertraitsAbstractFromAbstract<Left, Right> = {
+    [Key in Extract<keyof Left, keyof Right>]: Left[Key]
+} & {
+    [Key in Exclude<keyof Left, keyof Right>]: Left[Key]
+}
 
 
 export class TraitExpression<
@@ -54,10 +61,7 @@ export class TraitExpression<
     ) {
         return new Trait(
             this,
-            {} as Simplify<
+            {} as RemoveSupertraitsAbstractFromAbstract<SubtraitAbstract, Implements<typeof this>>,
-                CommonKeys<SubtraitAbstract, Implements<typeof this>> &
-                KeysOnlyInLeft<SubtraitAbstract, Implements<typeof this>>
-            >,
             apply as any as (Super: AbstractClass<{}>) => RemoveAbstractFromImplClass<SubtraitImplClassWithAbstract, SubtraitAbstract>,
         )
     }

src/lib.ts

@@ -0,0 +1,5 @@
+export {
+    abstract, expression, trait,
+    type Trait,
+    type TraitExpression
+} from "."