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Implement Arbitrary for AsMut<[T: Arbitrary]> #291
Description
Because of #265, it's no longer possible to do something like
#[derive(Clone, Debug)]
#[cfg_attr(test, derive(PartialEq, Eq))]
struct Foo {
foo: ChaChaPolyNonce, // has a BorrowMut<[u8]> impl
}
#[cfg(test)]
impl quickcheck::Arbitrary for Foo {
fn arbitrary(g: &mut quickcheck::Gen) -> Self {
let mut foo = ChaChaPolyNonce::default();
g.fill_bytes(&mut foo); // No more RngCore!
Self { foo }
}
}But it seems as though it would be reasonable to simply have an Arbitrary implementation for &mut [T: Arbitrary] that does fill_bytes internally.
Activity
neithernut commentedon May 22, 2021
Having
BorrowMut<[T: Arbitrary]> + Defaulttypes (or maybe some proxy/wrapper) implementArbitraryis certainly possible. But how would you implementArbitraryfor& mut [T: Arbitrary]based onfill_bytesin the general case?cyphar commentedon May 23, 2021
Sorry, I was trying to generalise the original issue I had (being unable to use
fill_byteswith the new quickcheck release) into being able to handle arbitrary&mut[T: Arbitrary]without adjusting how you would actually solve it.I also forgot that arbitrary doesn't take
&mut selfor anything so you'd need to implement it as aGenmethod instead, so something more like:I might just send a PR with this because the above works for me.
[-]Implement Arbitrary for &mut [T: Arbitrary][/-][+]Implement Arbitrary for AsMut<[T: Arbitrary]>[/+]