Help wanted: fast hash maps in std

[aturon]

I wanted to point out a relevant idea and commentary from the 2017 planning thread:

Setting our vision for the 2017 cycle

I brought this up in a different thread, but I think ‘insecure but fast hashing’ is a red herring in most cases. Instead, the default HashMap should use an adaptive scheme that starts with an insecure hash and switches to a secure one if an attack is detected (based on load factor and maximum distance of entries from their ideal location). That should provide the best of both worlds except if code size needs to be minimized, which is not the reason most people seem to want to use insecure hash…

Setting our vision for the 2017 cycle

This is a beautiful example of the kind of curve-bending that the Rust community has gotten so good at. Instead of just assuming that some ostensible tradeoff is a hard tradeoff, identify ways to get many of the benefits of both solutions at the same time. That shrinks down the set of cases that aren’t reasonably handled by the default (in this case, codebases with both fast-hash requirements and significant code size limitations), which makes the justification for escape valves much easier fo…

@comex, @wycats, maybe you can continue discussion here?