allow custom format on item for Debug

[ModProg]

Resolves #277

Synopsis

Solution

Checklist

• Documentation is updated (if required)
• Tests are added/updated (if required)
• CHANGELOG entry is added (if required)

[tyranron]

@ModProg thanks! What is missing is a full set of tests to cover this feature.

[tyranron]

@ModProg @JelteF also, it's a bit unclear how it should work with the item-level formatting attributes?

#[derive(Debug)]
#[debug("{name}={value:?}")]
struct Arg {
  #[debug("{name}!")]
  name: String,
  value: String
}

What should happen here?

1. Compilation error saying that we cannot mix top-level and field-level formatting attributes.
2. Print name!=value, considering the field-level formatting in top-level attribute.
3. Print name=value, silently ignoring the field-level formatting.

I'd vote for the option 1.

[JelteF]

it's a bit unclear how it should work with the item-level formatting attributes?

I think option 1 seems good.

[ModProg]

while 1. is definitly easier, 2. looks reasonable as well. but we can do that later, as it's a non breaking change.

[tyranron]

@ModProg at the moment, trait bounds for type parameters are being inferred incorrectly when top-level attribute comes into play. I've added tests covering those situations.

[JelteF]

I've added tests covering those situations.

Somehow github is not showing them in this PR (but I see them on the branch on @ModProg their fork). I'm assuming the tests are not passing?

[ModProg]

@JelteF @tyranron I added it to the bounds_generation. If a format argument is present for the container, its bounds replace the field bounds.

[tyranron]

@ModProg thank you! Very nice job and quite a thoughtful implementation! 👍

I've ripped some repeated parts a little bit more, though, and made some bikeshedings regarding errors terminology.

@JelteF would you like to take a look, or we can merge it?

[tyranron]

@JelteF could you make a 0.1.0-beta.3 release with fixes of recently merged PRs? I'd like to try it out on our codebase.

[JelteF]

could you make a 0.1.0-beta.3 release with fixes of recently merged PRs?

Done