| //@ known-bug: #149162 |
| use std::marker::PhantomData; |
| pub trait ViewArgument { |
| type Params<'a>; |
| } |
| |
| impl ViewArgument for () { |
| type Params<'a> = (); |
| } |
| |
| pub trait View {} |
| |
| pub fn buttons() -> Option<impl View> { |
| Some(()).map(|()| text_button(|()| {})) |
| } |
| pub fn text_button<State: ViewArgument>( |
| _: impl Fn(<State as ViewArgument>::Params<'_>), |
| ) -> Button<State, impl Fn()> { |
| Button { |
| callback: || (), |
| phantom: PhantomData, |
| } |
| } |
| pub struct Button<State, F> { |
| pub callback: F, |
| pub phantom: PhantomData<State>, |
| } |
| |
| impl<F> View for Button<(), F> {} |
| fn main() {} |
