src/lists.rs

   1 // Copyright 2015 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 use std::cmp;
  12 use std::iter::Peekable;
  13
  14 use syntax::codemap::{BytePos, CodeMap};
  15
  16 use {Indent, Shape};
  17 use comment::{find_comment_end, rewrite_comment, FindUncommented};
  18 use config::{Config, IndentStyle};
  19 use rewrite::RewriteContext;
  20 use utils::{first_line_width, last_line_width, mk_sp};
  21
  22 #[derive(Eq, PartialEq, Debug, Copy, Clone)]
  23 /// Formatting tactic for lists. This will be cast down to a
  24 /// DefinitiveListTactic depending on the number and length of the items and
  25 /// their comments.
  26 pub enum ListTactic {
  27     // One item per row.
  28     Vertical,
  29     // All items on one row.
  30     Horizontal,
  31     // Try Horizontal layout, if that fails then vertical.
  32     HorizontalVertical,
  33     // HorizontalVertical with a soft limit of n characters.
  34     LimitedHorizontalVertical(usize),
  35     // Pack as many items as possible per row over (possibly) many rows.
  36     Mixed,
  37 }
  38
  39 impl_enum_serialize_and_deserialize!(ListTactic, Vertical, Horizontal, HorizontalVertical, Mixed);
  40
  41 #[derive(Eq, PartialEq, Debug, Copy, Clone)]
  42 pub enum SeparatorTactic {
  43     Always,
  44     Never,
  45     Vertical,
  46 }
  47
  48 impl_enum_serialize_and_deserialize!(SeparatorTactic, Always, Never, Vertical);
  49
  50 impl SeparatorTactic {
  51     pub fn from_bool(b: bool) -> SeparatorTactic {
  52         if b {
  53             SeparatorTactic::Always
  54         } else {
  55             SeparatorTactic::Never
  56         }
  57     }
  58 }
  59
  60 pub struct ListFormatting<'a> {
  61     pub tactic: DefinitiveListTactic,
  62     pub separator: &'a str,
  63     pub trailing_separator: SeparatorTactic,
  64     pub shape: Shape,
  65     // Non-expressions, e.g. items, will have a new line at the end of the list.
  66     // Important for comment styles.
  67     pub ends_with_newline: bool,
  68     pub config: &'a Config,
  69 }
  70
  71 impl AsRef<ListItem> for ListItem {
  72     fn as_ref(&self) -> &ListItem {
  73         self
  74     }
  75 }
  76
  77 pub struct ListItem {
  78     // None for comments mean that they are not present.
  79     pub pre_comment: Option<String>,
  80     // Item should include attributes and doc comments. None indicates a failed
  81     // rewrite.
  82     pub item: Option<String>,
  83     pub post_comment: Option<String>,
  84     // Whether there is extra whitespace before this item.
  85     pub new_lines: bool,
  86 }
  87
  88 impl ListItem {
  89     pub fn inner_as_ref(&self) -> &str {
  90         self.item.as_ref().map_or("", |s| &*s)
  91     }
  92
  93     pub fn is_multiline(&self) -> bool {
  94         self.inner_as_ref().contains('\n') || self.pre_comment.is_some() ||
  95             self.post_comment
  96                 .as_ref()
  97                 .map_or(false, |s| s.contains('\n'))
  98     }
  99
 100     pub fn has_comment(&self) -> bool {
 101         self.pre_comment
 102             .as_ref()
 103             .map_or(false, |comment| comment.starts_with("//")) ||
 104             self.post_comment
 105                 .as_ref()
 106                 .map_or(false, |comment| comment.starts_with("//"))
 107     }
 108
 109     pub fn from_str<S: Into<String>>(s: S) -> ListItem {
 110         ListItem {
 111             pre_comment: None,
 112             item: Some(s.into()),
 113             post_comment: None,
 114             new_lines: false,
 115         }
 116     }
 117 }
 118
 119 #[derive(Eq, PartialEq, Debug, Copy, Clone)]
 120 /// The definitive formatting tactic for lists.
 121 pub enum DefinitiveListTactic {
 122     Vertical,
 123     Horizontal,
 124     Mixed,
 125 }
 126
 127 impl DefinitiveListTactic {
 128     pub fn ends_with_newline(&self, indent_style: IndentStyle) -> bool {
 129         match indent_style {
 130             IndentStyle::Block => *self != DefinitiveListTactic::Horizontal,
 131             IndentStyle::Visual => false,
 132         }
 133     }
 134 }
 135
 136 pub fn definitive_tactic<I, T>(items: I, tactic: ListTactic, width: usize) -> DefinitiveListTactic
 137 where
 138     I: IntoIterator<Item = T> + Clone,
 139     T: AsRef<ListItem>,
 140 {
 141     let pre_line_comments = items
 142         .clone()
 143         .into_iter()
 144         .any(|item| item.as_ref().has_comment());
 145
 146     let limit = match tactic {
 147         _ if pre_line_comments => return DefinitiveListTactic::Vertical,
 148         ListTactic::Mixed => return DefinitiveListTactic::Mixed,
 149         ListTactic::Horizontal => return DefinitiveListTactic::Horizontal,
 150         ListTactic::Vertical => return DefinitiveListTactic::Vertical,
 151         ListTactic::LimitedHorizontalVertical(limit) => ::std::cmp::min(width, limit),
 152         ListTactic::HorizontalVertical => width,
 153     };
 154
 155     let (sep_count, total_width) = calculate_width(items.clone());
 156     let sep_len = ", ".len(); // FIXME: make more generic?
 157     let total_sep_len = sep_len * sep_count.checked_sub(1).unwrap_or(0);
 158     let real_total = total_width + total_sep_len;
 159
 160     if real_total <= limit && !pre_line_comments &&
 161         !items.into_iter().any(|item| item.as_ref().is_multiline())
 162     {
 163         DefinitiveListTactic::Horizontal
 164     } else {
 165         DefinitiveListTactic::Vertical
 166     }
 167 }
 168
 169 // Format a list of commented items into a string.
 170 // TODO: add unit tests
 171 pub fn write_list<I, T>(items: I, formatting: &ListFormatting) -> Option<String>
 172 where
 173     I: IntoIterator<Item = T> + Clone,
 174     T: AsRef<ListItem>,
 175 {
 176     let tactic = formatting.tactic;
 177     let sep_len = formatting.separator.len();
 178
 179     // Now that we know how we will layout, we can decide for sure if there
 180     // will be a trailing separator.
 181     let mut trailing_separator = needs_trailing_separator(formatting.trailing_separator, tactic);
 182     let mut result = String::new();
 183     let cloned_items = items.clone();
 184     let mut iter = items.into_iter().enumerate().peekable();
 185     let mut item_max_width: Option<usize> = None;
 186
 187     let mut line_len = 0;
 188     let indent_str = &formatting.shape.indent.to_string(formatting.config);
 189     while let Some((i, item)) = iter.next() {
 190         let item = item.as_ref();
 191         let inner_item = try_opt!(item.item.as_ref());
 192         let first = i == 0;
 193         let last = iter.peek().is_none();
 194         let mut separate = !last || trailing_separator;
 195         let item_sep_len = if separate { sep_len } else { 0 };
 196
 197         // Item string may be multi-line. Its length (used for block comment alignment)
 198         // should be only the length of the last line.
 199         let item_last_line = if item.is_multiline() {
 200             inner_item.lines().last().unwrap_or("")
 201         } else {
 202             inner_item.as_ref()
 203         };
 204         let mut item_last_line_width = item_last_line.len() + item_sep_len;
 205         if item_last_line.starts_with(indent_str) {
 206             item_last_line_width -= indent_str.len();
 207         }
 208
 209         match tactic {
 210             DefinitiveListTactic::Horizontal if !first => {
 211                 result.push(' ');
 212             }
 213             DefinitiveListTactic::Vertical if !first => {
 214                 result.push('\n');
 215                 result.push_str(indent_str);
 216             }
 217             DefinitiveListTactic::Mixed => {
 218                 let total_width = total_item_width(item) + item_sep_len;
 219
 220                 // 1 is space between separator and item.
 221                 if line_len > 0 && line_len + 1 + total_width > formatting.shape.width {
 222                     result.push('\n');
 223                     result.push_str(indent_str);
 224                     line_len = 0;
 225                     if tactic == DefinitiveListTactic::Mixed && formatting.ends_with_newline {
 226                         if last {
 227                             separate = true;
 228                         } else {
 229                             trailing_separator = true;
 230                         }
 231                     }
 232                 }
 233
 234                 if line_len > 0 {
 235                     result.push(' ');
 236                     line_len += 1;
 237                 }
 238
 239                 line_len += total_width;
 240             }
 241             _ => {}
 242         }
 243
 244         // Pre-comments
 245         if let Some(ref comment) = item.pre_comment {
 246             // Block style in non-vertical mode.
 247             let block_mode = tactic != DefinitiveListTactic::Vertical;
 248             // Width restriction is only relevant in vertical mode.
 249             let comment = try_opt!(rewrite_comment(
 250                 comment,
 251                 block_mode,
 252                 formatting.shape,
 253                 formatting.config,
 254             ));
 255             result.push_str(&comment);
 256
 257             if tactic == DefinitiveListTactic::Vertical {
 258                 result.push('\n');
 259                 result.push_str(indent_str);
 260             } else {
 261                 result.push(' ');
 262             }
 263             item_max_width = None;
 264         }
 265
 266         result.push_str(&inner_item[..]);
 267
 268         // Post-comments
 269         if tactic != DefinitiveListTactic::Vertical && item.post_comment.is_some() {
 270             let comment = item.post_comment.as_ref().unwrap();
 271             let formatted_comment = try_opt!(rewrite_comment(
 272                 comment,
 273                 true,
 274                 Shape::legacy(formatting.shape.width, Indent::empty()),
 275                 formatting.config,
 276             ));
 277
 278             result.push(' ');
 279             result.push_str(&formatted_comment);
 280         }
 281
 282         if separate {
 283             result.push_str(formatting.separator);
 284         }
 285
 286         if tactic == DefinitiveListTactic::Vertical && item.post_comment.is_some() {
 287             let comment = item.post_comment.as_ref().unwrap();
 288             let overhead = last_line_width(&result) + first_line_width(comment.trim());
 289
 290             let rewrite_post_comment = |item_max_width: &mut Option<usize>| {
 291                 if item_max_width.is_none() && !last && !inner_item.contains('\n') {
 292                     *item_max_width = Some(max_width_of_item_with_post_comment(
 293                         &cloned_items,
 294                         i,
 295                         overhead,
 296                         formatting.config.max_width(),
 297                     ));
 298                 }
 299                 let overhead = if let &mut Some(max_width) = item_max_width {
 300                     max_width + 2
 301                 } else {
 302                     // 1 = space between item and comment.
 303                     item_last_line_width + 1
 304                 };
 305                 let width = formatting.shape.width.checked_sub(overhead).unwrap_or(1);
 306                 let offset = formatting.shape.indent + overhead;
 307                 let comment_shape = Shape::legacy(width, offset);
 308
 309                 // Use block-style only for the last item or multiline comments.
 310                 let block_style = !formatting.ends_with_newline && last ||
 311                     comment.trim().contains('\n') ||
 312                     comment.trim().len() > width;
 313
 314                 rewrite_comment(comment, block_style, comment_shape, formatting.config)
 315             };
 316
 317             let mut formatted_comment = try_opt!(rewrite_post_comment(&mut item_max_width));
 318
 319             if !formatted_comment.starts_with('\n') {
 320                 let mut comment_alignment =
 321                     post_comment_alignment(item_max_width, inner_item.len());
 322                 if first_line_width(&formatted_comment) + last_line_width(&result) +
 323                     comment_alignment + 1 > formatting.config.max_width()
 324                 {
 325                     item_max_width = None;
 326                     formatted_comment = try_opt!(rewrite_post_comment(&mut item_max_width));
 327                     comment_alignment = post_comment_alignment(item_max_width, inner_item.len());
 328                 }
 329                 for _ in 0..(comment_alignment + 1) {
 330                     result.push(' ');
 331                 }
 332                 // An additional space for the missing trailing comma
 333                 if last && item_max_width.is_some() && !separate {
 334                     result.push(' ');
 335                 }
 336             }
 337             if formatted_comment.contains('\n') {
 338                 item_max_width = None;
 339             }
 340             result.push_str(&formatted_comment);
 341         } else {
 342             item_max_width = None;
 343         }
 344
 345         if !last && tactic == DefinitiveListTactic::Vertical && item.new_lines {
 346             item_max_width = None;
 347             result.push('\n');
 348         }
 349     }
 350
 351     Some(result)
 352 }
 353
 354 fn max_width_of_item_with_post_comment<I, T>(
 355     items: &I,
 356     i: usize,
 357     overhead: usize,
 358     max_budget: usize,
 359 ) -> usize
 360 where
 361     I: IntoIterator<Item = T> + Clone,
 362     T: AsRef<ListItem>,
 363 {
 364     let mut max_width = 0;
 365     let mut first = true;
 366     for item in items.clone().into_iter().skip(i) {
 367         let item = item.as_ref();
 368         let inner_item_width = item.inner_as_ref().len();
 369         if !first &&
 370             (item.is_multiline() || !item.post_comment.is_some() ||
 371                 inner_item_width + overhead > max_budget)
 372         {
 373             return max_width;
 374         }
 375         if max_width < inner_item_width {
 376             max_width = inner_item_width;
 377         }
 378         if item.new_lines {
 379             return max_width;
 380         }
 381         first = false;
 382     }
 383     max_width
 384 }
 385
 386 fn post_comment_alignment(item_max_width: Option<usize>, inner_item_len: usize) -> usize {
 387     item_max_width
 388         .and_then(|max_line_width| max_line_width.checked_sub(inner_item_len))
 389         .unwrap_or(0)
 390 }
 391
 392 pub struct ListItems<'a, I, F1, F2, F3>
 393 where
 394     I: Iterator,
 395 {
 396     codemap: &'a CodeMap,
 397     inner: Peekable<I>,
 398     get_lo: F1,
 399     get_hi: F2,
 400     get_item_string: F3,
 401     prev_span_end: BytePos,
 402     next_span_start: BytePos,
 403     terminator: &'a str,
 404 }
 405
 406 impl<'a, T, I, F1, F2, F3> Iterator for ListItems<'a, I, F1, F2, F3>
 407 where
 408     I: Iterator<Item = T>,
 409     F1: Fn(&T) -> BytePos,
 410     F2: Fn(&T) -> BytePos,
 411     F3: Fn(&T) -> Option<String>,
 412 {
 413     type Item = ListItem;
 414
 415     fn next(&mut self) -> Option<Self::Item> {
 416         let white_space: &[_] = &[' ', '\t'];
 417
 418         self.inner.next().map(|item| {
 419             let mut new_lines = false;
 420             // Pre-comment
 421             let pre_snippet = self.codemap
 422                 .span_to_snippet(mk_sp(self.prev_span_end, (self.get_lo)(&item)))
 423                 .unwrap();
 424             let trimmed_pre_snippet = pre_snippet.trim();
 425             let has_pre_comment =
 426                 trimmed_pre_snippet.contains("//") || trimmed_pre_snippet.contains("/*");
 427             let pre_comment = if has_pre_comment {
 428                 Some(trimmed_pre_snippet.to_owned())
 429             } else {
 430                 None
 431             };
 432
 433             // Post-comment
 434             let next_start = match self.inner.peek() {
 435                 Some(next_item) => (self.get_lo)(next_item),
 436                 None => self.next_span_start,
 437             };
 438             let post_snippet = self.codemap
 439                 .span_to_snippet(mk_sp((self.get_hi)(&item), next_start))
 440                 .unwrap();
 441
 442             let comment_end = match self.inner.peek() {
 443                 Some(..) => {
 444                     let mut block_open_index = post_snippet.find("/*");
 445                     // check if it realy is a block comment (and not //*)
 446                     if let Some(i) = block_open_index {
 447                         if i > 0 && &post_snippet[i - 1..i] == "/" {
 448                             block_open_index = None;
 449                         }
 450                     }
 451                     let newline_index = post_snippet.find('\n');
 452                     let separator_index = post_snippet.find_uncommented(",").unwrap();
 453
 454                     match (block_open_index, newline_index) {
 455                         // Separator before comment, with the next item on same line.
 456                         // Comment belongs to next item.
 457                         (Some(i), None) if i > separator_index => separator_index + 1,
 458                         // Block-style post-comment before the separator.
 459                         (Some(i), None) => cmp::max(
 460                             find_comment_end(&post_snippet[i..]).unwrap() + i,
 461                             separator_index + 1,
 462                         ),
 463                         // Block-style post-comment. Either before or after the separator.
 464                         (Some(i), Some(j)) if i < j => cmp::max(
 465                             find_comment_end(&post_snippet[i..]).unwrap() + i,
 466                             separator_index + 1,
 467                         ),
 468                         // Potential *single* line comment.
 469                         (_, Some(j)) if j > separator_index => j + 1,
 470                         _ => post_snippet.len(),
 471                     }
 472                 }
 473                 None => post_snippet
 474                     .find_uncommented(self.terminator)
 475                     .unwrap_or(post_snippet.len()),
 476             };
 477
 478             if !post_snippet.is_empty() && comment_end > 0 {
 479                 // Account for extra whitespace between items. This is fiddly
 480                 // because of the way we divide pre- and post- comments.
 481
 482                 // Everything from the separator to the next item.
 483                 let test_snippet = &post_snippet[comment_end - 1..];
 484                 let first_newline = test_snippet.find('\n').unwrap_or(test_snippet.len());
 485                 // From the end of the first line of comments.
 486                 let test_snippet = &test_snippet[first_newline..];
 487                 let first = test_snippet
 488                     .find(|c: char| !c.is_whitespace())
 489                     .unwrap_or(test_snippet.len());
 490                 // From the end of the first line of comments to the next non-whitespace char.
 491                 let test_snippet = &test_snippet[..first];
 492
 493                 if test_snippet.chars().filter(|c| c == &'\n').count() > 1 {
 494                     // There were multiple line breaks which got trimmed to nothing.
 495                     new_lines = true;
 496                 }
 497             }
 498
 499             // Cleanup post-comment: strip separators and whitespace.
 500             self.prev_span_end = (self.get_hi)(&item) + BytePos(comment_end as u32);
 501             let post_snippet = post_snippet[..comment_end].trim();
 502
 503             let post_snippet_trimmed = if post_snippet.starts_with(',') {
 504                 post_snippet[1..].trim_matches(white_space)
 505             } else if post_snippet.ends_with(',') {
 506                 post_snippet[..(post_snippet.len() - 1)].trim_matches(white_space)
 507             } else {
 508                 post_snippet
 509             };
 510
 511             let post_comment = if !post_snippet_trimmed.is_empty() {
 512                 Some(post_snippet_trimmed.to_owned())
 513             } else {
 514                 None
 515             };
 516
 517             ListItem {
 518                 pre_comment: pre_comment,
 519                 item: (self.get_item_string)(&item),
 520                 post_comment: post_comment,
 521                 new_lines: new_lines,
 522             }
 523         })
 524     }
 525 }
 526
 527 // Creates an iterator over a list's items with associated comments.
 528 pub fn itemize_list<'a, T, I, F1, F2, F3>(
 529     codemap: &'a CodeMap,
 530     inner: I,
 531     terminator: &'a str,
 532     get_lo: F1,
 533     get_hi: F2,
 534     get_item_string: F3,
 535     prev_span_end: BytePos,
 536     next_span_start: BytePos,
 537 ) -> ListItems<'a, I, F1, F2, F3>
 538 where
 539     I: Iterator<Item = T>,
 540     F1: Fn(&T) -> BytePos,
 541     F2: Fn(&T) -> BytePos,
 542     F3: Fn(&T) -> Option<String>,
 543 {
 544     ListItems {
 545         codemap: codemap,
 546         inner: inner.peekable(),
 547         get_lo: get_lo,
 548         get_hi: get_hi,
 549         get_item_string: get_item_string,
 550         prev_span_end: prev_span_end,
 551         next_span_start: next_span_start,
 552         terminator: terminator,
 553     }
 554 }
 555
 556 fn needs_trailing_separator(
 557     separator_tactic: SeparatorTactic,
 558     list_tactic: DefinitiveListTactic,
 559 ) -> bool {
 560     match separator_tactic {
 561         SeparatorTactic::Always => true,
 562         SeparatorTactic::Vertical => list_tactic == DefinitiveListTactic::Vertical,
 563         SeparatorTactic::Never => false,
 564     }
 565 }
 566
 567 /// Returns the count and total width of the list items.
 568 fn calculate_width<I, T>(items: I) -> (usize, usize)
 569 where
 570     I: IntoIterator<Item = T>,
 571     T: AsRef<ListItem>,
 572 {
 573     items
 574         .into_iter()
 575         .map(|item| total_item_width(item.as_ref()))
 576         .fold((0, 0), |acc, l| (acc.0 + 1, acc.1 + l))
 577 }
 578
 579 fn total_item_width(item: &ListItem) -> usize {
 580     comment_len(item.pre_comment.as_ref().map(|x| &(*x)[..])) +
 581         comment_len(item.post_comment.as_ref().map(|x| &(*x)[..])) +
 582         item.item.as_ref().map_or(0, |str| str.len())
 583 }
 584
 585 fn comment_len(comment: Option<&str>) -> usize {
 586     match comment {
 587         Some(s) => {
 588             let text_len = s.trim().len();
 589             if text_len > 0 {
 590                 // We'll put " /*" before and " */" after inline comments.
 591                 text_len + 6
 592             } else {
 593                 text_len
 594             }
 595         }
 596         None => 0,
 597     }
 598 }
 599
 600 // Compute horizontal and vertical shapes for a struct-lit-like thing.
 601 pub fn struct_lit_shape(
 602     shape: Shape,
 603     context: &RewriteContext,
 604     prefix_width: usize,
 605     suffix_width: usize,
 606 ) -> Option<(Option<Shape>, Shape)> {
 607     let v_shape = match context.config.struct_lit_style() {
 608         IndentStyle::Visual => try_opt!(
 609             try_opt!(shape.visual_indent(0).shrink_left(prefix_width)).sub_width(suffix_width)
 610         ),
 611         IndentStyle::Block => {
 612             let shape = shape.block_indent(context.config.tab_spaces());
 613             Shape {
 614                 width: try_opt!(context.config.max_width().checked_sub(shape.indent.width())),
 615                 ..shape
 616             }
 617         }
 618     };
 619     let shape_width = shape.width.checked_sub(prefix_width + suffix_width);
 620     if let Some(w) = shape_width {
 621         let shape_width = cmp::min(w, context.config.struct_lit_width());
 622         Some((Some(Shape::legacy(shape_width, shape.indent)), v_shape))
 623     } else {
 624         Some((None, v_shape))
 625     }
 626 }
 627
 628 // Compute the tactic for the internals of a struct-lit-like thing.
 629 pub fn struct_lit_tactic(
 630     h_shape: Option<Shape>,
 631     context: &RewriteContext,
 632     items: &[ListItem],
 633 ) -> DefinitiveListTactic {
 634     if let Some(h_shape) = h_shape {
 635         let prelim_tactic = match (context.config.struct_lit_style(), items.len()) {
 636             (IndentStyle::Visual, 1) => ListTactic::HorizontalVertical,
 637             _ => context.config.struct_lit_multiline_style().to_list_tactic(),
 638         };
 639         definitive_tactic(items, prelim_tactic, h_shape.width)
 640     } else {
 641         DefinitiveListTactic::Vertical
 642     }
 643 }
 644
 645 // Given a tactic and possible shapes for horizontal and vertical layout,
 646 // come up with the actual shape to use.
 647 pub fn shape_for_tactic(
 648     tactic: DefinitiveListTactic,
 649     h_shape: Option<Shape>,
 650     v_shape: Shape,
 651 ) -> Shape {
 652     match tactic {
 653         DefinitiveListTactic::Horizontal => h_shape.unwrap(),
 654         _ => v_shape,
 655     }
 656 }
 657
 658 // Create a ListFormatting object for formatting the internals of a
 659 // struct-lit-like thing, that is a series of fields.
 660 pub fn struct_lit_formatting<'a>(
 661     shape: Shape,
 662     tactic: DefinitiveListTactic,
 663     context: &'a RewriteContext,
 664     force_no_trailing_comma: bool,
 665 ) -> ListFormatting<'a> {
 666     let ends_with_newline = context.config.struct_lit_style() != IndentStyle::Visual &&
 667         tactic == DefinitiveListTactic::Vertical;
 668     ListFormatting {
 669         tactic: tactic,
 670         separator: ",",
 671         trailing_separator: if force_no_trailing_comma {
 672             SeparatorTactic::Never
 673         } else {
 674             context.config.trailing_comma()
 675         },
 676         shape: shape,
 677         ends_with_newline: ends_with_newline,
 678         config: context.config,
 679     }
 680 }