// Some unusual code minimized from
// https://github.com/sile/handy_async/tree/7b619b762c06544fc67792c8ff8ebc24a88fdb98

pub trait Pattern {
    type Value;
}

pub struct Constrain<A, B = A, C = A>(A, B, C);

impl<A, B, C> Pattern for Constrain<A, B, C>
    where A: Pattern,
          B: Pattern<Value = A::Value>,
          C: Pattern<Value = A::Value>,
{
    type Value = A::Value;
}

pub struct Wrapper<T>(T);

impl<T> Pattern for Wrapper<T> {
    type Value = T;
}


// @has self_referential/struct.WriteAndThen.html
// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header"]' \
// "impl<P1> Send for WriteAndThen<P1>where    <P1 as Pattern>::Value: Send"
pub struct WriteAndThen<P1>(pub P1::Value,pub <Constrain<P1, Wrapper<P1::Value>> as Pattern>::Value)
    where P1: Pattern;
