MinPin: yet another pin proposal · baby steps

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2024-11-06 01:30:04

This post floats a variation of boats’ UnpinCell proposal that I’m calling MinPin.1 MinPin’s goal is to integrate Pin into the language in a “minimally disruptive” way2 – and in particular a way that is fully backwards compatible. Unlike Overwrite, MinPin does not attempt to make Pin and &mut “play nicely” together. It does however leave the door open to add Overwrite in the future, and I think helps to clarify the positives and negatives that Overwrite would bring.

Yes. I think the rule of thumb would be this. For any given type, you should decide whether your type cares about pinning or not.

Most types do not care about pinning. They just go on using &self and &mut self as normal. Everything works as today (this is the “zero-conceptual-cost” goal).

But some types do care about pinning. These are typically future implementations but they could be other special case things. In that case, you should explicitly implement !Unpin to declare yourself as pinnable. When you declare your methods, you have to make a choice