swc/crates/swc_ecma_parser/tests/tsc/subtypingWithObjectMembers5.ts

interface Base {
    foo: string;
}

interface Derived extends Base {
    bar: string;
}

// N and M have the same name, same accessibility, same optionality, and N is a subtype of M
// foo properties are valid, bar properties cause errors in the derived class declarations
module NotOptional {
    interface A {
        foo: Base;
    }

    class B implements A {
        fooo: Derived; // error
    }

    interface A2 {
        1: Base;
    }

    class B2 implements A2 {
        2: Derived; // error
    }

    interface A3 {
        '1': Base;
    }

    class B3 implements A3 {
        '1.0': Derived; // error
    }
}

// same cases as above but with optional
module Optional {
    interface A {
        foo?: Base;
    }

    class B implements A {
        fooo: Derived; // weak type error
    }

    interface A2 {
        1?: Base;
    }

    class B2 implements A2 {
        2: Derived; // weak type error
    }

    interface A3 {
        '1'?: Base;
    }

    class B3 implements A3 {
        '1.0': Derived; // weak type error
    }
}