"No route matched" warning in yew-router

[MakotoE]

Question

I am getting this warning in my web browser on an app using yew-router.

src/router.rs:228 No route matched, provide a redirect prop to the router to handle cases where no route can be matched

I edited the counter example to add the router, passing both render and redirect props.

diff --git a/examples/counter/src/main.rs b/examples/counter/src/lib.rs
rename from examples/counter/src/main.rs
rename to examples/counter/src/lib.rs
--- a/examples/counter/src/main.rs	(revision d5ac6cdb85fc5f5f5a7a1fcdf6bf519832037bde)
+++ b/examples/counter/src/lib.rs	(date 1607923711863)
@@ -1,6 +1,10 @@
+#![recursion_limit="256"]
 use js_sys::Date;
 use yew::services::ConsoleService;
 use yew::{html, Component, ComponentLink, Html, ShouldRender};
+use yew::prelude::*;
+use yew_router::prelude::*;
+use wasm_bindgen::prelude::*;
 
 pub enum Msg {
     Increment,
@@ -66,6 +70,52 @@
     }
 }
 
-fn main() {
-    yew::start_app::<Model>();
+#[derive(Clone, Switch)]
+pub enum Route {
+    #[to = "/fileviewer"]
+    FileViewer,
+    #[to = "/"]
+    Index,
+}
+
+pub struct Page {}
+
+impl Component for Page {
+    type Message = ();
+    type Properties = ();
+
+    fn create(props: Self::Properties, link: ComponentLink<Self>) -> Self {
+        Self{}
+    }
+
+    fn update(&mut self, msg: Self::Message) -> bool {
+        false
+    }
+
+    fn change(&mut self, _props: Self::Properties) -> bool {
+        false
+    }
+
+    fn view(&self) -> Html {
+        let render = Router::render(|switch: Route| match switch {
+            Route::FileViewer => html!{<p>{"fileviewer"}</p>},
+            Route::Index => html! {<Model />},
+        });
+        let redirect = Router::redirect(|route: yew_router::route::Route| {
+            ConsoleService::log("page not found");
+            Route::Index
+        });
+        html! {
+            <Router<Route>
+                render = render,
+                redirect = redirect,
+            />
+        }
+    }
+}
+
+#[wasm_bindgen(start)]
+pub fn start() {
+    wasm_logger::init(wasm_logger::Config::default());
+    yew::App::<Page>::new().mount_to_body();
 }

How do I change this code to fix the warning?

What I've tried (optional)

I looked at the router example but it's quite a complex program and I don't know what it does differently than mine.

[samoylovfp]

I get this warning when running the example from master branch of this repo
revision cc51208a4878f25cae29edd56428b2988b45d5ff.
Even though, judging by the console output, the route is actually matched later, after the warning was emitted.

Happens both in

Chromium Version 89.0.4389.114 (Official Build) snap (64-bit)

and

Firefox 87.0 (64-bit)

[siku2]

This should no longer be an issue with the new router introduced in #1791.
The warning still exists, but it should only be emitted when actually no route matched.