Adding route_with_tsr creates fallback behaviour

[alper]

I have this router setup:

    Router::new()
        .merge(admin::router())
        .route_layer(login_required!(Backend, login_url = "/login"))
        .merge(public::router())
        .merge(auth::router())

Trying to add route_with_tsr to the routes in two of the routers creates this error message: "Cannot merge two MethodRouters that both have a fallback"

I think it has something to do with the merge behaviour messing with the fallbacks but what I don't get is why this happens when I start adding route_with_tsr since it looks like that only adds more routes and does not do anything else.

[jplatte]

Can you please share a fully reproducible example? This may be a duplicate of #1347.