Stack overflow declaring mutually recursive traits

[erickt]

This code causes rustc's stack to overflow:

trait Hash<H: Hasher> { }
trait Hasher<H: Hash> { }

trait StreamHash<H: StreamHasher>: Hash<H> { }
trait StreamHasher<H: StreamHash>: Hasher<H> { }

fn main() {
}

As a workaround, you can break up the recursion with another trait:

trait Hash { }
trait Hasher<H: Hash> { }

trait Stream { }
trait StreamHash<S: Stream>: Hash { }
trait StreamHasher<H: StreamHash<Self>>: Stream + Hasher<H> { }

fn main() { }

[reem]

There seems to have been no progress on this issue. Does anyone know what might be the source of the problem or what could be done to fix it?

[frewsxcv]

trait Hash<H: Hasher<Self>> {
    fn f(&self, _: H) {}
}

trait Hasher<H: Hash<Self>> {
    fn g(&self, _: H) {}
}

trait StreamHash<H: StreamHasher<Self>>: Hash<H> {
    fn h(&self, _: H) {}
}

trait StreamHasher<H: StreamHash<Self>>: Hasher<H> {
    fn i(&self, _: H) {}
}

fn main() {
}

I updated the original code block to compile with the latest Rust. I had to add methods for each trait to avoid the compiler complaining about unused type parameters. Also had to add <Self> to all the inherited trait types. That said, this compiles and runs for me with no stack overflows. Is this issue still valid or is my code rewrite not equivalent to the original example?

[tamird]

No longer reproducible.