[0.7] Callback can't be passed as listener

[DanielleHuisman]

Describe the bug

Passing a Callback as listener gives an error:

#[component]
fn TestButton(#[prop(into)] on_click: Callback<MouseEvent>, children: Children) -> impl IntoView {
    view! {
        <button on:click=on_click>
            {children()}
        </button>
    }
}

error[E0277]: expected a `FnMut(leptos::ev::MouseEvent)` closure, found `leptos::prelude::Callback<leptos::ev::MouseEvent>`
   --> packages/leptos/button/src/default.rs:114:5
    |
114 | /     view! {
115 | |         <button on:click=on_click>
    | |                 -- required by a bound introduced by this call
116 | |             {children()}
117 | |         </button>
118 | |     }
    | |_____^ expected an `FnMut(leptos::ev::MouseEvent)` closure, found `leptos::prelude::Callback<leptos::ev::MouseEvent>`
    |
    = help: the trait `FnMut(leptos::ev::MouseEvent)` is not implemented for `leptos::prelude::Callback<leptos::ev::MouseEvent>`, which is required by `leptos::html::HtmlElement<leptos::html::Button, (), (leptos::prelude::AnyView,)>: leptos::prelude::OnAttribute<_, _>`
    = help: the trait `leptos::prelude::OnAttribute<E, F>` is implemented for `leptos::html::HtmlElement<El, At, Ch>`
    = note: required for `leptos::html::HtmlElement<leptos::html::Button, (), (leptos::prelude::AnyView,)>` to implement `leptos::prelude::OnAttribute<leptos::ev::click, leptos::prelude::Callback<leptos::ev::MouseEvent>>`

However, manually calling .run() works fine:

#[component]
fn TestButton(#[prop(into)] on_click: Callback<MouseEvent>, children: Children) -> impl IntoView {
    view! {
        <button on:click=move |event| on_click.run(event)>
            {children()}
        </button>
    }
}

Leptos Dependencies

# Latest commit on main branch
leptos = { git = "https://github.com/leptos-rs/leptos.git", rev = "c2b239d" }

Expected behavior

I would expect Callback to be accepted as is, without manually calling .run().

It might be nice for Option<Callback<T>> to be accepted as well, so you can create an
#[prop(into, optional)] on_click: Option<Callback<MouseEvent>>.

[gbj]

Unfortunately this is working as designed. I have attempted to implement this in the past and not been successful. I'm open to a PR that successfully implements it directly.

I would recommend taking impl FnMut(MouseEvent) + 'static or a similar type for on_click in the examples above.