diff --git a/src/makeSchemableClass.ts b/src/makeSchemableClass.ts
index e14700d..8268b52 100644
--- a/src/makeSchemableClass.ts
+++ b/src/makeSchemableClass.ts
@@ -4,7 +4,13 @@ import { StaticMembers } from "./util"
 
 
 export function makeSchemableClassFrom<
-    C                 extends AbstractClass<any, []>,
+    C extends AbstractClass<{
+        schema?:         never
+        defaultValues?:  never
+    }, []> & {
+        schema?:         never
+        defaultValues?:  never
+    },
 
     SchemaT           extends z.ZodRawShape,
     SchemaUnknownKeys extends z.UnknownKeysParam,
@@ -44,7 +50,7 @@ export function makeSchemableClassFrom<
         }
     } as unknown as (
         Class<
-            Omit<InstanceType<C>, "schema" | "defaultValues"> &
+            InstanceType<C> &
             {
                 readonly schema:         typeof schema,
                 readonly defaultValues:  typeof defaultValues,
@@ -54,7 +60,7 @@ export function makeSchemableClassFrom<
             Parameters<(values: Values) => void>
         > &
 
-        Omit<StaticMembers<C>, "schema" | "defaultValues"> &
+        StaticMembers<C> &
         {
             readonly schema:         typeof schema,
             readonly defaultValues:  typeof defaultValues,