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// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// 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 required
Stream::result(&stream)
}
}
impl<H: StreamHasher> StreamHash<H> for u8 {
fn input_stream(&self, stream: &mut H::S) {
Stream::input(stream, &[*self]);
}
}
fn main() {}
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