1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
|
// 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() {}
|
