type_id collision

gistfile1.rs

use std::hash;
use std::hash::Streaming;

// I believe that this pretty much the same thing as hash_crate_independent() in ty.rs
// for a ty_struct on a 64-bit platform
fn hash_struct(local_hash: &str, node: u64) -> u64 {
    let mut state = hash::default_state();
    state.input([18]);
    state.input(local_hash.as_bytes());
    do node.iter_bytes(true) |bytes| { state.input(bytes); true };
    state.result_u64()
}

fn main() {
    // This represents two structures with different node values from a crate with a local_hash value
    // of "local" that end up getting the same hash and thus, I think, the same type_id
    assert!(hash_struct("local", 0x9e02c8943c336302) == hash_struct("local", 0x366a806b1d5f1b2));
}