Does not error

gistfile1.txt

interface Animal {
	size: number;
}
interface Cat extends Animal {
	furry: boolean;
}
interface Human extends Animal {
	name: string;
}

interface CatVeterinarian {
    checkup(a: Cat, owner: Human): void;
}

interface HumanDoctor {
    checkup(a: Human): void;
}

class UniversalDoctor implements CatVeterinarian, HumanDoctor {
    // would expect this to error but it does not
    checkup() {
        // ...
    }
}