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use disjoint_impls::disjoint_impls;
pub trait Dispatch {
type Group;
}
pub enum GroupA {}
impl Dispatch for String {
type Group = GroupA;
}
impl<T> Dispatch for Vec<T> {
type Group = GroupA;
}
pub enum GroupB {}
impl Dispatch for i32 {
type Group = GroupB;
}
impl Dispatch for u32 {
type Group = GroupB;
}
disjoint_impls! {
pub trait Kita<U>: Dispatch
where
U: From<u8> + From<bool>,
{
const NAME: &'static str;
}
impl<U, T: Dispatch<Group = GroupA>> Kita<U> for T
where
U: From<u8> + From<bool>,
{
const NAME: &'static str = "Blanket A";
}
impl<U, T: Dispatch<Group = GroupB>> Kita<U> for T
where
U: From<u8> + From<bool>,
{
const NAME: &'static str = "Blanket B";
}
}
/*
pub trait Kita<U>: Dispatch
where
U: From<u8> + From<bool>,
{
const NAME: &'static str;
}
const _: () = {
pub trait Kita0<_TŠČ1: ?Sized, U>: Dispatch
where
U: From<u8> + From<bool>,
{
const NAME: &'static str;
}
impl<U, T: Dispatch<Group = GroupA>> Kita0<GroupA, U> for T
where
U: From<u8> + From<bool>,
{
const NAME: &'static str = "Blanket A";
}
impl<U, T: Dispatch<Group = GroupB>> Kita0<GroupB, U> for T
where
U: From<u8> + From<bool>,
{
const NAME: &'static str = "Blanket B";
}
// TODO: Some of the bounds are repeated. Remove duplication
impl<_TŠČ0, _TŠČ1> Kita<_TŠČ0> for _TŠČ1
where
_TŠČ0: From<u8> + From<bool>,
Self: Dispatch,
_TŠČ0: From<bool>,
_TŠČ0: From<u8>,
_TŠČ1: Dispatch,
Self: Kita0<<_TŠČ1 as Dispatch>::Group, _TŠČ0>,
{
const NAME: &'static str = <Self as Kita0<
<_TŠČ1 as Dispatch>::Group,
_TŠČ0,
>>::NAME;
}
};
*/
#[test]
fn extra_parameter() {
assert_eq!("Blanket A", <String as Kita<u8>>::NAME);
assert_eq!("Blanket A", <Vec::<u32> as Kita<u16>>::NAME);
assert_eq!("Blanket B", <u32 as Kita<u32>>::NAME);
assert_eq!("Blanket B", <i32 as Kita<u64>>::NAME);
}