fix: remove redundant Required<> from input and output type definitions

[yz89122]

Summary

• Removes redundant Required<> utility type from both input and output type definitions
• Fixes TS2615 circular reference errors in TypeScript 5.9+
• No functional changes - the type behavior remains identical

Problem

The Required<> utility type in both type definitions was redundant:

export type input<T> = T extends { _zod: { input: any } } ? Required<T["_zod"]>["input"] : unknown;
export type output<T> = T extends { _zod: { output: any } } ? Required<T["_zod"]>["output"] : unknown;

The type guards T extends { _zod: { input: any } } and T extends { _zod: { output: any } } already ensure that input and output are required properties. If either were optional, the conditions would fail and return unknown.

This redundant Required<> caused TS2615 errors in TypeScript 5.9+ when using recursive schemas because it introduced unnecessary mapped types in circular reference chains.

Solution

Simplified both type definitions to:

export type input<T> = T extends { _zod: { input: any } } ? T["_zod"]["input"] : unknown;
export type output<T> = T extends { _zod: { output: any } } ? T["_zod"]["output"] : unknown;

The type behavior remains exactly the same, but without the redundant mapped type transformations.

Test plan

• Tested with TypeScript 5.5.4 - all tests pass (283 test files, 2805 tests)
• Tested with TypeScript 5.9.2 - all tests pass (283 test files, 2805 tests)
• Verified recursive type definitions work correctly

Related

Fixes #5035

🤖 Generated with Claude Code

[colinhacks]

Thanks for the excellent issue and PR. My heart dropped when I saw a TS 5.9 incompatibility with ts5.9. Glad this was an easy fix 😅 I guess those Required<> calls are vestigial...I forget why I ever added them.