rustfmt should keep array types together when possible
Author: jrose-signalCreated Jul 22, 2026Updated Sep 9, 2026
LabelsC-bugI-poor-formatting
Summary
I tried to format this code:
pub(super) const ENCRYPTED_USERNAME_ENTROPY: [u8; usernames::constants::USERNAME_LINK_ENTROPY_SIZE] =
const_str::hex!("4302c613c092a51c5394becffeb6f697300a605348e93f03c3db95e0b03d28f1");(don't worry, this is not sensitive entropy data, it was generated for a test case)
Expected behavior
I expected to get this, splitting after the colon:
pub(super) const ENCRYPTED_USERNAME_ENTROPY:
[u8; usernames::constants::USERNAME_LINK_ENTROPY_SIZE] =
const_str::hex!("4302c613c092a51c5394becffeb6f697300a605348e93f03c3db95e0b03d28f1");Actual behavior
Instead, rustfmt did this, splitting the array type after the semicolon:
pub(super) const ENCRYPTED_USERNAME_ENTROPY: [u8;
usernames::constants::USERNAME_LINK_ENTROPY_SIZE] =
const_str::hex!("4302c613c092a51c5394becffeb6f697300a605348e93f03c3db95e0b03d28f1");Configuration
None
Meta
Playground rustfmt 1.9.0-stable, also 1.9.0-nightly (0e29c21d93 2026-07-21)
Source: rust-lang/rustfmt