The Hashtable Problem: A Litmus Test for External Impl Proposals
Rust Internals [Unofficial]
June 13, 2026
- Crate A defines
struct Key - Crate B defines:
impl Hash for Key use AlterHashB - Crate C defines:
impl Hash for Key use AlterHashC - The bin depends A,B,C, there is also casting from
HashMap<Key + Hash use AlterHashB, _>toHashMap<Key + Hash use AlterHashC, _>
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