Confusing missing property error in a circular situation

🔎 Search Terms

missing property mapped type getter deferred

🕗 Version & Regression Information

• This is the behavior in every version I tried

⏯ Playground Link

https://www.typescriptlang.org/play/?ts=6.0.0-dev.20250802#code/JYOwLgpgTgZghgYwgAgFoHsAmAVAngBwgB5sA+ZAbwChll18xh0Q4AbALmQCIwoBXCF2QAfbvFYBnQQG4adPmHwLO2WQF8qVUJFiIUGTAGVeoAObIIAD0ghMEtFjyEiEkyFPlqteo2ZtOXOJSXOqaYAT6WIYAFnCEyAC8yABKEAjoUJgubqYANMhwILiksuHxAApQEGCMMLgk5EkUyADaANLIoMgA1hC46DDI2AC6Ku3DyGrIAGSUaqURyACSIDDQAPIARgBWaWBOxDFxKFY2dg5GsYSNyJXVtfVyXrSt3Z0gPX0DyEfxcPa-CAtboTU4QWz2Zo+JgsDjcXgCIQaF4vAD8PTkKM4IAgADdoMNUZxAcDhi0uOgFEowFxhrJaFNZs9aMD3p9+oNAQUAVcgSCLNZwecoQwYf54fxBJNMWjkDj8VAZbROCDibzSeTKYoFLT6dKSlpwNB4EgLltdggwCQBWd7AZAeQwRCLgciCs1lBzXtXWRPHJoX44YE2MFQoadCbIph1qLA9anecDK7CsVSHIE3bHBESJqqTqJqI+LYIDBQBBMH7vLHYQEETIqBoqJg0qw4FVkDAi5aYXQdnt44LnfbeaQABQSXkqACUnAMXstDVkzYQrfbnZA3eYyFcUDMo5nF2Mu-cS5bbZQ683HwDsIHtpd2ZTpDHEgQ0QgAFs4NPZ1gY75bzIWQqHSEBXGQABhOBIFMDJcESXsLTAUdnhYD8IE4Hc9ynXI5FMapkHwc9wH3SgZSqMA+Cga9qzYUcoJguCpz1NRcLUZjNCsfAMjAZBQPArVqQQhiIFgqBcAAOkEhRZCAA

💻 Code

interface ZodType<T> {
  optional: "true" | "false";
  output: T;
}

interface ZodString extends ZodType<string> {
  optional: "false";
}

type ZodShape = Record<string, any>;
type Prettify<T> = { [K in keyof T]: T[K] } & {};
type InferObjectType<Shape extends ZodShape> = Prettify<
  {
    [k in keyof Shape as Shape[k] extends { optional: "true" }
      ? k
      : never]?: Shape[k]["output"];
  } & {
    [k in keyof Shape as Shape[k] extends { optional: "true" }
      ? never
      : k]: Shape[k]["output"];
  }
>;
interface ZodObject<T extends ZodShape> extends ZodType<InferObjectType<T>> {
  optional: "false";
}

interface ZodOptional<T extends ZodType<any>>
  extends ZodType<T["output"] | undefined> {
  optional: "true";
}

declare function object<T extends ZodShape>(shape: T): ZodObject<T>;
declare function string(): ZodString;
declare function optional<T extends ZodType<any>>(schema: T): ZodOptional<T>;

const Category = object({
  name: string(),
  get parent() {
    // Argument of type 'ZodObject<{ name: ZodString; readonly parent: ZodOptional<ZodType<any>>; }>' is not assignable to parameter of type 'ZodType<any>'.
    //   Property 'output' is missing in type 'ZodObject<{ name: ZodString; readonly parent: ZodOptional<ZodType<any>>; }>' but required in type 'ZodType<any>'.(2345)
    return optional(Category);
  },
});

export const output = Category.output;

🙁 Actual behavior

A very confusing error is produced here. A ZodObject extends ZodType and that has an output property so how it can be missing?

🙂 Expected behavior

I don't expect to see this error

Additional information about the issue

Note that if we remove export const output = Category.output; then we can see a new error appearing:

'parent' implicitly has return type 'any' because it does not have a return type annotation and is referenced directly or indirectly in one of its return expressions.(7023)

And this one makes sense (but I'd argue the other one shouldn't appear at all in this scenario).

This has changed with https://github.com/microsoft/TypeScript/pull/58337 , before this PR the circularity error was present with and without export const output = Category.output;