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

// merged interfaces behave as if all extends clauses from each declaration are merged together
// no errors expected

class C {
    a: number;
}

class C2 {
    b: number;
}

interface A extends C {
    y: string;
}

interface A extends C2 {
    z: string;
}

class D implements A {
    a: number;
    b: number;
    y: string;
    z: string;
}

var a: A;
var r = a.a;

// generic interfaces in a module
module M {
    class C<T> {
        a: T;
    }

    class C2<T> {
        b: T;
    }

    interface A<T> extends C<T> {
        y: T;
    }

    interface A<T> extends C2<string> {
        z: T;
    }

    class D implements A<boolean> {
        a: boolean;
        b: string;
        y: boolean;
        z: boolean;
    }
}