Regenerated setter causes invalid override

[Schahen]

Following code:

interface Dict<T> {
    [key: string]: T | undefined;
}

interface BasicHeaders extends Dict<string | string[]> {
    'retry-after'?: string;
    'set-cookie'?: string[];
}

export interface ExtendedHeaders extends BasicHeaders {
    ":path"?: string;
}

is translated to:

external interface Dict<T> {
    @nativeGetter
    operator fun get(key: String): T?
    @nativeSetter
    operator fun set(key: String, value: T?)
}

external interface BasicHeaders : Dict<dynamic /* String | Array<String> */> {
    override operator fun get(key: String): Any?
    override operator fun set(key: String, value: Any?)
}

external interface ExtendedHeaders : BasicHeaders {
    override operator fun get(key: String): String?
    override operator fun set(key: String, value: String?)
}

which actually will fail to compile:

out/index.module_tmp.kt:32:5: error: 'set' overrides nothing
    override operator fun set(key: String, value: String?)
    ^