Property bar does not exist on type in the docs example using TS4.8.4

[s10z]

Prerequisites

• [X] I have written a descriptive issue title
• [X] I have searched existing issues to ensure the bug has not already been reported

Fastify version

4.9.2

Plugin version

2.1.1

Node.js version

16.13.0

Operating system

Linux

Operating system version (i.e. 20.04, 11.3, 10)

22.04

Description

Hi.

I stumbled over the example code of the fastify docs, similar to the closed issue https://github.com/fastify/fastify-type-provider-json-schema-to-ts/issues/12. There is a TypeScript Playground Link given where everything is expected to be properly configured. As I were unable to extract all desired information, I moved to codesandbox with the given code I had to add the dependencies there.

Final the setup is:

package.json

{
  "dependencies": {
    "typescript": "4.8.4",
    "fastify": "^4.9.2",
    "@fastify/type-provider-json-schema-to-ts": "^2.1.1"
  },
  "description": "TypeScript playground exported Sandbox",
  "name": "TypeScript Playground Export",
  "version": "0.0.0"
}

tsconfig.json

{
  "compilerOptions": {
    "strict": true,
    "noImplicitAny": true,
    "strictNullChecks": true,
    "strictFunctionTypes": true,
    "strictPropertyInitialization": true,
    "strictBindCallApply": true,
    "noImplicitThis": true,
    "noImplicitReturns": true,
    "alwaysStrict": true,
    "esModuleInterop": true,
    "declaration": true,
    "experimentalDecorators": true,
    "emitDecoratorMetadata": true,
    "target": "ES2017",
    "jsx": "react",
    "module": "ESNext",
    "moduleResolution": "node"
  }
}

and index.ts

import { JsonSchemaToTsProvider } from "@fastify/type-provider-json-schema-to-ts";

import fastify from "fastify";

const server = fastify().withTypeProvider<JsonSchemaToTsProvider>();

server.get(
  "/route",
  {
    schema: {
      querystring: {
        type: "object",
        properties: {
          foo: { type: "number" },
          bar: { type: "string" }
        },
        required: ["foo", "bar"]
      }
    } as const
  },
  (request) => {
    const { bar } = request.query;
    bar.push("foo"); // I'd expect this to fail with `error TS2339: Property 'push' does not exist on type string`
  }
);

as you can see, the desired unwrapping does not take place. Instead it says: "property bar does not exist on type unkndown" What am I doing wrong? Or did it break with the new TS version that has been released (our assumption)?

Steps to Reproduce

Use code outlined above. Ensure to use Typescript Version 4.8.4. Or see the live example at codesandbox

Expected Behavior

No response