Add Self: Sized constraint to by_ref #66
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| @@ -482,7 +482,9 @@ pub trait Signal { | |||
| /// assert_eq!(signal.next(), [4]); | |||
| /// } | |||
| /// ``` | |||
| fn by_ref(&mut self) -> &mut Self { | |||
| fn by_ref(&mut self) -> &mut Self | |||
| where Self: Sized | |||
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I'm still unsure why this is necessary? I'm happy to add it if it is necesary, I'm just curious what cause for it is - is there some compile error or warning if we don't have this?
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Yeah, it means that Signal is not object-safe because there's a method that uses Self in its return type. This disallows that. The advantage to object safety is that was can return abstract Box<Signal> from a function.
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Ahhh I see, I don't often use trait objects so haven't run into this for a while, but that makes sense!
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It looks like there are a couple compile errors showing up in the nightly build when type checking with |
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I was wondering what that failure was and how to reproduce it. Yeah, just need to import Box explicitly. |
This extends the existing implementation for `&'a mut S where S: Signal` and `Box<Signal>` to be a little more general. E.g. `&mut my_signal as &mut Signal` now produces a `&mut Signal` trait object which also implements `Signal`. Boxed signals no longer require the `Sized` bound in order to implement `Signal` themselves, E.g. the `Sized` bound in `Box<Signal<Frame=[f32; 2]> + Sized>` is no longer necessary. These changes now reflect the implementations of `Iterator` for `&mut Iterator` and `Box<Iterator>` in the std library. cc @andrewcsmith this alters the `Signal` impl for `Box<Signal>` introduced in RustAudio#66, however I don't believe this is a breaking change as it should be strictly more general 👍
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