mirror of
https://github.com/rust-lang/rust.git
synced 2024-12-05 05:04:24 +00:00
39 lines
933 B
Rust
39 lines
933 B
Rust
// Test an example where we fail to infer the type parameter H. This
|
|
// is because there is really nothing constraining it. At one time, we
|
|
// would infer based on the where clauses in scope, but that no longer
|
|
// works.
|
|
|
|
trait Hash<H> {
|
|
fn hash2(&self, hasher: &H) -> u64;
|
|
}
|
|
|
|
trait Stream {
|
|
fn input(&mut self, bytes: &[u8]);
|
|
fn result(&self) -> u64;
|
|
}
|
|
|
|
trait StreamHasher {
|
|
type S : Stream;
|
|
fn stream(&self) -> Self::S;
|
|
}
|
|
|
|
trait StreamHash<H: StreamHasher>: Hash<H> {
|
|
fn input_stream(&self, stream: &mut H::S);
|
|
}
|
|
|
|
impl<H: StreamHasher> Hash<H> for u8 {
|
|
fn hash2(&self, hasher: &H) -> u64 {
|
|
let mut stream = hasher.stream();
|
|
self.input_stream(&mut stream); //~ ERROR type annotations needed
|
|
Stream::result(&stream)
|
|
}
|
|
}
|
|
|
|
impl<H: StreamHasher> StreamHash<H> for u8 {
|
|
fn input_stream(&self, stream: &mut H::S) {
|
|
Stream::input(stream, &[*self]);
|
|
}
|
|
}
|
|
|
|
fn main() {}
|