Derive Debug impls

[lnicola]

Not sure this is an improvement, but hey, at least it fixes a TODO.

I also sneaked in a Cargo.toml change to avoid a warning.

[Pauan]

Looks good to me, thanks!

[Pauan]

One thing I would suggest is to increase the version of wasm-bindgen to 0.2.41, since that's the version that introduced Debug for Closure.

[lnicola]

Filed rustwasm/wasm-bindgen#1477 for the JsFuture impl.

I'm actually not sure that this PR is a good change, since it makes the debug output more crowded while saving a couple of lines of code.

[Pauan]

Debug isn't really intended to be "clean", it's intended for situations where you're debugging problems.

So it's usually better to err on the side of providing more information.

[lnicola]

So it's usually better to err on the side of providing more information.

Sure, but if it's always going to print a JsFuture { ... } field, it doesn't bring anything of value. I see it like Sender.

[Pauan]

It does provide value though: it lets you know that it's implemented with JsFuture (so you can then go and look up the docs/implementation for that).

Also, not using derive(Debug) is a refactoring hazard, since somebody might forget to update the Debug impl when making changes to the type.

[lnicola]

This is now ready, methinks.

[fitzgen]

Thanks!