Fix short-if formatting

[csmoe]

Cloese #2777

[csmoe]

@nrc how can I auto-update the target files formatting when making some changes in rustfmt codebase? I used to update them with cargo run --bin rustfmt xxx.rs, but when the formatting is controlled by config, this won't work.

[topecongiro]

Thanks for the PR!

[topecongiro]

Thanks for the PR!

[topecongiro]

I think that this is incorrect. We should only put the if expression in a single line if it is the last statement of the block.

[topecongiro]

This should not happen, we never put a block statement in a single line.

[topecongiro]

So is this one.

[topecongiro]

And this one too.

[nrc]

how can I auto-update the target files formatting when making some changes in rustfmt codebase?

There's no good way to do this, sorry. If all the tests have the same config, then you can just create a rustfmt.toml and put it in some surrounding directory, then run rustfmt. Otherwise you have to do things manually.

[csmoe]

@topecongiro ping for review.

[topecongiro]

Thank you for the update! Though the current implementation is not correct yet: we only want to put an if statement on a single line only if it is the last statement.

So for example,

fn f() {
    if x { foo() } else { bar() }
    if x { foo() } else { bar() }
}

should become

fn f() {
    if x { 
        foo() 
    } else { 
        bar() 
    }
    if x { foo() } else { bar() }
}

[topecongiro]

Thank you for the update! Though the current implementation is not correct yet: we only want to put an if statement on a single line only if it is the last statement.

So for example,

fn f() {
    if x { foo() } else { bar() }
    if x { foo() } else { bar() }
}

should become

fn f() {
    if x { 
        foo() 
    } else { 
        bar() 
    }
    if x { foo() } else { bar() }
}

[topecongiro]

This is a bit hacky - you can inspect the ast::ExprKind to see whether the given expression is if or not.

[petrochenkov]

@topecongiro @csmoe
Any way to move this forward / prioritize?

[topecongiro]

@csmoe @petrochenkov My apologies for the late reply. I missed the notification of new commits being pushed to this PR.

Since this could not get merged before 1.0 release, the formatting change needs to be version gated. Also we need to fix the merge conflicts. I think in the current form getting these done are a bit tough, so I would rather fix the issue in a separate PR.

@csmoe Again, I am very sorry that I could not review the PR in a timely manner. I really appreciate your contribution to rustfmt.