src/TraitBuilder.ts

@@ -1,4 +1,4 @@
-import { AbstractClass, Simplify } from "type-fest"
+import { AbstractClass, Class, Simplify } from "type-fest"
 import { Trait } from "./Trait"
 import { TraitExpression } from "./TraitExpression"
 import { Extend, StaticMembers } from "./util"
@@ -128,6 +128,40 @@ export type ImplStatic<
     >
 )
 
+export function implStaticThis<
+    ImplClass extends AbstractClass<object> & { readonly [implSuperSymbol]: true },
+    This      extends AbstractClass<object>,
+>(
+    _Impl:    ImplClass,
+    thisArg:  This,
+) {
+    return thisArg as unknown as (
+        AbstractClass<
+            InstanceType<ImplClass> & InstanceType<This>,
+            ConstructorParameters<This>
+        > &
+        ImplStatic<ImplClass> &
+        StaticMembers<This>
+    )
+}
+
+export function implStaticInstantiableThis<
+    ImplClass extends AbstractClass<object> & { readonly [implSuperSymbol]: true },
+    This      extends Class<object>,
+>(
+    _Impl:    ImplClass,
+    thisArg:  This,
+) {
+    return thisArg as unknown as (
+        Class<
+            InstanceType<ImplClass> & InstanceType<This>,
+            ConstructorParameters<This>
+        > &
+        ImplStatic<ImplClass> &
+        StaticMembers<This>
+    )
+}
+
 
 export const trait = new TraitBuilder(
     new TraitExpression(TraitExpression.NullSuperclass, []),

src/lib.ts

@@ -1,4 +1,4 @@
 export { Trait, TraitClass, TraitConcreteClass, TraitInstance, TraitStaticMembers, TraitTuple } from "./Trait"
-export { ImplStatic, TraitBuilder, trait } from "./TraitBuilder"
+export { ImplStatic, TraitBuilder, implStaticInstantiableThis, implStaticThis, trait } from "./TraitBuilder"
 export { Implements, StaticImplements, TraitExpression, TraitExpressionClass, TraitExpressionConcreteClass, TraitExpressionInstance, TraitExpressionStaticMembers } from "./TraitExpression"
 export { TraitExpressionBuilder, expression } from "./TraitExpressionBuilder"