"left behind trailing whitespace" when breaking after visibility of a field

[jplatte]

$ rustup run nightly cargo fmt -- --check
Diff in /home/jplatte/code/matrix-rust-sdk/crates/matrix-sdk/src/room/timeline/event_item/content.rs at line 292:
 /// of the sender of the reaction.
 #[derive(Clone, Debug, Default)]
 pub struct ReactionGroup(
-    pub(in crate::room::timeline)
+    pub(in crate::room::timeline) 
         IndexMap<(Option<OwnedTransactionId>, Option<OwnedEventId>), OwnedUserId>,
 );
 
error[internal]: left behind trailing whitespace
   --> /home/jplatte/code/matrix-rust-sdk/crates/matrix-sdk/src/room/timeline/event_item/content.rs:295:295:34
    |
295 |     pub(in crate::room::timeline) 
    |                                  ^
    |

[ytmimi]

@jplatte thanks for reaching out. Can you post the original code snippet instead of the diff. Additionally, what version of rustfmt are you using and are you using any non default configuration options?

[jplatte]

This is from matrix-org/matrix-rust-sdk#1599 before pulling out the inner type of ReactionGroup in crates/matrix-sdk/src/room/timeline/event_item/content.rs into a type alias. The version of rustfmt that produces this error is 1.5.2-nightly (7281249 2023-02-27). Does that answer your questions?

[ytmimi]

Yeah, that helps! I just want to be clear that this was the original input snippet, and that there was no trailing whitespace to begin with.

#[derive(Clone, Debug, Default)]
pub struct ReactionGroup(
    pub(in crate::room::timeline)
        IndexMap<(Option<OwnedTransactionId>, Option<OwnedEventId>), OwnedUserId>,
);