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rustfmt wraps comments too tightly on first trait bound #7148
Description
Sometimes I have comments to put on bounds within a where clause. For example:
unsafe impl<T> Sync for PinnedOnceLock<T>
where
// Shared access to the PinnedOnceLock<T> also allows for creating T on a thread that may be
// different from the one that later destroys the PinnedOnceLock<T>. So T also needs to be Send.
T: Send,
// Shared access to the PinnedOnceLock<T> allows for shared access to T, so T needs to be Sync
// in order for the PinnedOnceLock<T> to be Sync.
T: Sync,
{
}For some reason, in this syntactic position wrap_comments wants to make the first comment much shorter than the second, even though comment_width is set appropriately:
> cat config.toml
wrap_comments = true
comment_width = 100
> rustfmt +nightly --version
rustfmt 1.11.0-nightly (75a75c3e0a 2026-09-26)
> rustfmt +nightly --emit=stdout --config-path config.toml foo.rs
unsafe impl<T> Sync for PinnedOnceLock<T>
where
// Shared access to the PinnedOnceLock<T> also allows for
// creating T on a thread that may be different from
// the one that later destroys the PinnedOnceLock<T>. So T
// also needs to be Send.
T: Send,
// Shared access to the PinnedOnceLock<T> allows for shared access to T, so T needs to be Sync
// in order for the PinnedOnceLock<T> to be Sync.
T: Sync,
{
}
Activity
maxdexh commentedon Sep 28, 2026
jieyouxu commentedon Sep 28, 2026
fix(items): format comments after where using clause_shape budget
fix(items): format comments after where using clause_shape budget
fix(items): format comments after where using clause_shape budget
jacobsa commentedon Oct 2, 2026
Thanks very much!
fix(items): format comments after where using clause_shape budget