Include trailing comma in single param vertical fn#6890
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When formatting a function with a single parameter with `fn_params_layout` set to `Vertical`, the previous tactic would remove any trailing commas before spilling to multiple lines for other reasons, such as long function names or return types. Instead, use the same tactic as `Tall` does, so that the trailing comma is kept if the end result spans multiple lines. Issue rust-lang#6889 `fn_params_layout = "Vertical"` removes single argument's trailing comma
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Thanks. Considering
- Self-consistency with
fn_params_layout = "Tall"which already adds trailing commas for single param fn, and - Inserting a trailing comma is generally better for minimizing extra diff lines
This makes sense to me. However, I think the fix needs to be gated behind a style edition.
| match self { | ||
| Density::Compressed => ListTactic::Mixed, | ||
| Density::Tall => ListTactic::HorizontalVertical, | ||
| Density::Vertical if len == 1 => ListTactic::Horizontal, |
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Problem: AFAICT, fn_params_layout is a stable option and fn_params_layout = "Vertical" is a stable value. This means that to uphold rustfmt's strict formatting stability guarantees, I believe this change needs to be gated behind the next style edition.
Can you:
- Gate this change behind the next style edition + keep the old format intact for previous style editions
- Add a second copy of
fn_params_layout/vertical.rstest (vertical_style_2027.rsor sth) that specifies// rustfmt-style_edition: 2027+// rustfmt-fn_params_layout: Verticalwhich demonstrates the "fixed" formatting, but also demonstrating that the previous formatting remains unchanged?
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When formatting a function with a single parameter with
fn_params_layoutset toVertical, the previous tactic would remove any trailing commas before spilling to multiple lines for other reasons, such as long function names or return types. Instead, use the same tactic asTalldoes, so that the trailing comma is kept if the end result spans multiple lines.Resolves #6889
fn_params_layout = "Vertical"removes single argument's trailing comma