tsdown builds fine and ignores typecheck errors

[Badisi]

Reproduction link or steps

package.json

{
    "scripts": {
        "build": "tsdown index.ts --dts"
    },
    "devDependencies": {
        "tsdown": "^0.21.10",
        "typescript": "^6.0.3"
    }
}

index.ts

export const config: Config = {};

Steps:

1. Run npm install
2. Run npm run build

What is expected?

tsdown should complain about missing type as tsc does:

$ npx tsc index.ts --noEmit

index.ts:1:22 - error TS2304: Cannot find name 'Config'.

1 export const config: Config = {};
~~~~~~

Found 1 error in index.ts:1

What is actually happening?

tsdown is building without issues.

Any additional comments?

No response