Compiler unexpectedly panicked when formatting code #5876
Comments
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@gianzellweger when you have a moment can you please provide a minimal code snippet inline that we can run rustfmt on with your configuration to reproduce the issue. something like: fn main() {
// code that reproduces the issue
}Without an example code snippet there's very little we can do to help. |
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@ytmimi Is there a way to see which code it was trying to format? The entire project has about 2000 LOC and I do not think that satisfies the "minimal code snippet" requirement. I also tried it with another project and there it worked like intended. |
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@gianzellweger first, I want to say thanks for bringing this to our attention. If you can try to narrow it down that would be great. Just looking at the logs you've provided I think this might be a duplicate of #4968 |
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@ytmimi I have now narrowed it down to a single file (which is still 1000 lines, so not a helpful progression) and I have tried deactivating every single configuration on its own. The panic only goes away if I remove |
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Normally I'd recommend running rustfmt with Any chance you can share a link to the file? |
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@ytmimi How about I instead narrow it down to the specific piece of code? There's only about 10-20 functions which I can comment out separately until the error goes away. |
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Alright, I had a look at this and I think I've got it. In your case the error is happening in the |
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@ytmimi That fixed it, thank you so much. Can we agree that this isn't optimal behavior from rustfmt and could be improved? Not trying to put any pressure on anybody. |
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@gianzellweger this particular issue will almost certainly be resolved once we add support for Here's a bit of a deep dive explanation into what's happening in this case: fn fail() {
if let Some(x) = x && y {
format!("{:name_width$} {:temperature_width$.2}°C {:critical_width$}")
// ^
// |
// |
// trailing whitespace
}
}and here's a screenshot that highlights the whitespace at the end: 
The issue is that rustfmt doesn't currently support formatting At the end of the formatting process rustfmt does a pass over that output buffer to see if there are instances of trailing whitespace or lines that exceed the |
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@ytmimi That makes a lot of sense, as my code uses let-chains. Is there any issue that tracks the progress of this or has this implementation not started at all? Thank you once more. |
ytmimi
added
bug
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The example input from #5888 is also really helpful at highlighting this issue: pub(crate) fn sanity_needs_ocr<T: HasWord + HasRect>(collection: &[T]) -> bool {
let needs_ocr = collection.is_empty()
// the presence of 'UNICODE REPLACEMENT CHARACTER'
|| collection.iter().any(|c| c.text().contains('�'))
// (yes, empty pages will also be OCR'd)
|| collection_is_void_of_text(collection)
|| is_gibberish(&collection.to_rendered_text());
#[cfg(debug_assertions)]
if needs_ocr {
tracing::trace!(
"sanity check failed, with text: {:?}",
collection.to_rendered_text()
);
}
needs_ocr
}and here's my explanation of the problem: #5888 (comment) |
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I found a much smaller example that triggers the same error: #![allow(incomplete_features)]
#![feature(
try_blocks,
never_type,
min_specialization,
exclusive_range_pattern,
lazy_cell
)]Putting that as input into There's no |
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@danielhuang thanks! The tab characters are what's causing the panic. Similar issues have been reported before. An explanation of what's going on can be found at #4968 (comment), and there are PRs already open to resolve your case. |
I recently looked through all the features of Rustfmt and picked a few options where I preferred some option over the default. When trying this new mix, however, I got an error. I have attached both the log and my configuration.
rustc-ice-2023-08-02T21:08:46.715244Z-75321.txt
rustfmt.toml
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