Pass State in as a reference #3
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| H: (FnOnce(State) -> Fut) + RefUnwindSafe + Copy + Send + Sync + 'static, | ||
| Fut: Future<Output = HandlerResult> + Send + 'static, | ||
| H: (FnOnce(&'_ mut State) -> Fut) + RefUnwindSafe + Copy + Send + Sync + 'static, | ||
| Fut: Future<Output = HandlerResult> + Send, |
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The problem is that you can't tie the lifetime of State to that of Fut, because it has no lifetime parameters, and therefore no way to specify the required higher-ranked lifetime bounds ( https://doc.rust-lang.org/reference/trait-bounds.html#higher-ranked-trait-bounds ). If I manage to work-around this issue then it should fix gotham-rs#431 . I am going to chase this up in the upstream rust repo here:
rust-lang/rust#45994
If we manage to fix this, I will also have a good solution to the ergonomics problems in tag1consulting/goose#22
There is a slightly more self-contained exploration of this issue here: https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=63830174a65ea4adf45eb5b095f0ae9b
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Can the state parameter be a generic parameter of the state middleware, and mutability (or not) left entirely up to the user, by their choice (or not) of a mutable reference type like |
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Just closing some old PRs. Nothing to see here. |
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