Does anyone know why the code below has a type error even if there is already a if guard before the code that creates the variant variable?

How could I fix that without writing my own user-defined type guard?

type PersonDetails = {
  gender: 'man' | 'woman',
  height: 'tall' | 'short',
}

export type PersonVariant =
  | {
      gender: 'man',
      height: 'tall',
    }
  | {
      gender: 'woman',
      height: 'tall',
    }
  | {
      gender: 'woman',
      height: 'short',
    };

const details = {} as PersonDetails;

function test() {
    if (details.gender === 'man' && details.height === 'short') {
        return;
    }

    const variant: PersonVariant = {
        gender: details.gender,
        height: details.height,
    };
}