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Format Rust code
https://rust-lang.github.io/rustfmt/
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Format issue on supertrait with bounds on associated types. #6316

Open gui1117 opened 2 months ago

gui1117 commented 2 months ago

For all version I could tests (master and nightly)

this code:

pub trait MyLongTraitName:
    MyLongBoundName<
        MyLongAssociatedType:
            SomeAnotherBound<
                YetAnotherType: YetAnotherBound,
                YetAnotherType2: YetAnotherBound2
            >,
        OtherType: SmallBound
            + SmallBound2
            + AnotherLongBound<
                WithSomeType: BeingBound,
                WithSomeType2: BeingBound,
                WithSomeType3: BeingBound
            >
            + SmallBound3
            + AnotherLongBound2<
                WithSomeType: BeingBound,
                WithSomeType2: BeingBound,
                WithSomeType3: BeingBound
            >,
    >
{
}

fn main() {}

gets formatted into:

pub trait MyLongTraitName:
    MyLongBoundName<
    MyLongAssociatedType: SomeAnotherBound<
        YetAnotherType: YetAnotherBound,
        YetAnotherType2: YetAnotherBound2,
    >,
    OtherType: SmallBound
                   + SmallBound2
                   + AnotherLongBound<
        WithSomeType: BeingBound,
        WithSomeType2: BeingBound,
        WithSomeType3: BeingBound,
    > + SmallBound3
                   + AnotherLongBound2<
        WithSomeType: BeingBound,
        WithSomeType2: BeingBound,
        WithSomeType3: BeingBound,
    >,
>
{
}

fn main() {}
ytmimi commented 2 months ago

Thanks for the report. Confirming I can reproduce this the latest master rustfmt 1.7.1-nightly (1a70f40d7f 2024-09-03)

gui1117 commented 2 months ago

It seems those types are formatted with the overflow formatting, do you suggest to change the overflow formatting or change formatting so it doesn't go into overflow?

ytmimi commented 2 months ago

@gui1117 have you started looking into this issue?

gui1117 commented 2 months ago

@gui1117 have you started looking into this issue?

Not really, and I would prefer not because I struggle to understand the code. But I look a bit when I have free time.

ytmimi commented 2 months ago

@gui1117 no worries. Based on https://github.com/rust-lang/rustfmt/issues/6316#issuecomment-2339597525 I thought maybe you'd looked through the code.

Not really, and I would prefer not because I struggle to understand the code.

It's quite a tricky part of the codebase. Definitely don't feel obligated to dive in.