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// check-pass
#![allow(dead_code)]
trait ParseError {
type StreamError;
}
impl<T> ParseError for T {
type StreamError = ();
}
trait Stream {
type Item;
type Error: ParseError;
}
trait Parser
where
<Self as Parser>::PartialState: Default,
{
type PartialState;
fn parse_mode(_: &Self, _: Self::PartialState) {
loop {}
}
}
impl Stream for () {
type Item = ();
type Error = ();
}
impl Parser for () {
type PartialState = ();
}
struct AndThen<A, B>(core::marker::PhantomData<(A, B)>);
impl<A, B> Parser for AndThen<A, B>
where
A: Stream,
B: Into<<A::Error as ParseError>::StreamError>,
{
type PartialState = ();
}
fn expr<A>() -> impl Parser
where
A: Stream<Error = <A as Stream>::Item>,
{
AndThen::<A, ()>(core::marker::PhantomData)
}
fn parse_mode_impl<A>()
where
<A as Stream>::Error: ParseError,
A: Stream<Error = <A as Stream>::Item>,
{
Parser::parse_mode(&expr::<A>(), Default::default())
}
fn main() {}
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