1 use rustc_ast::ast::{self, BindingMode, Pat, PatField, PatKind, RangeEnd, RangeSyntax};
3 use rustc_span::{BytePos, Span};
5 use crate::comment::{combine_strs_with_missing_comments, FindUncommented};
6 use crate::config::lists::*;
7 use crate::config::Version;
8 use crate::expr::{can_be_overflowed_expr, rewrite_unary_prefix, wrap_struct_field};
10 definitive_tactic, itemize_list, shape_for_tactic, struct_lit_formatting, struct_lit_shape,
11 struct_lit_tactic, write_list, ListFormatting, ListItem, Separator,
13 use crate::macros::{rewrite_macro, MacroPosition};
15 use crate::pairs::{rewrite_pair, PairParts};
16 use crate::rewrite::{Rewrite, RewriteContext};
17 use crate::shape::Shape;
18 use crate::source_map::SpanUtils;
19 use crate::spanned::Spanned;
20 use crate::types::{rewrite_path, PathContext};
21 use crate::utils::{format_mutability, mk_sp, mk_sp_lo_plus_one, rewrite_ident};
23 /// Returns `true` if the given pattern is "short".
24 /// A short pattern is defined by the following grammar:
28 /// - `&[single-line, ntp]`
32 /// - unary tuple constructor `([small, ntp])`
34 pub(crate) fn is_short_pattern(pat: &ast::Pat, pat_str: &str) -> bool {
35 // We also require that the pattern is reasonably 'small' with its literal width.
36 pat_str.len() <= 20 && !pat_str.contains('\n') && is_short_pattern_inner(pat)
39 fn is_short_pattern_inner(pat: &ast::Pat) -> bool {
41 ast::PatKind::Rest | ast::PatKind::Wild | ast::PatKind::Lit(_) => true,
42 ast::PatKind::Ident(_, _, ref pat) => pat.is_none(),
43 ast::PatKind::Struct(..)
44 | ast::PatKind::MacCall(..)
45 | ast::PatKind::Slice(..)
46 | ast::PatKind::Path(..)
47 | ast::PatKind::Range(..) => false,
48 ast::PatKind::Tuple(ref subpats) => subpats.len() <= 1,
49 ast::PatKind::TupleStruct(_, ref path, ref subpats) => {
50 path.segments.len() <= 1 && subpats.len() <= 1
52 ast::PatKind::Box(ref p) | ast::PatKind::Ref(ref p, _) | ast::PatKind::Paren(ref p) => {
53 is_short_pattern_inner(&*p)
55 PatKind::Or(ref pats) => pats.iter().all(|p| is_short_pattern_inner(p)),
59 struct RangeOperand<'a>(&'a Option<ptr::P<ast::Expr>>);
61 impl<'a> Rewrite for RangeOperand<'a> {
62 fn rewrite(&self, context: &RewriteContext<'_>, shape: Shape) -> Option<String> {
64 None => Some("".to_owned()),
65 Some(ref exp) => exp.rewrite(context, shape),
70 impl Rewrite for Pat {
71 fn rewrite(&self, context: &RewriteContext<'_>, shape: Shape) -> Option<String> {
73 PatKind::Or(ref pats) => {
76 .map(|p| p.rewrite(context, shape))
77 .collect::<Option<Vec<_>>>()?;
79 let use_mixed_layout = pats
82 .all(|(pat, pat_str)| is_short_pattern(pat, pat_str));
83 let items: Vec<_> = pat_strs.into_iter().map(ListItem::from_str).collect();
84 let tactic = if use_mixed_layout {
85 DefinitiveListTactic::Mixed
89 ListTactic::HorizontalVertical,
90 Separator::VerticalBar,
94 let fmt = ListFormatting::new(shape, context.config)
97 .separator_place(context.config.binop_separator())
98 .ends_with_newline(false);
99 write_list(&items, &fmt)
101 PatKind::Box(ref pat) => rewrite_unary_prefix(context, "box ", &**pat, shape),
102 PatKind::Ident(binding_mode, ident, ref sub_pat) => {
103 let (prefix, mutability) = match binding_mode {
104 BindingMode::ByRef(mutability) => ("ref", mutability),
105 BindingMode::ByValue(mutability) => ("", mutability),
107 let mut_infix = format_mutability(mutability).trim();
108 let id_str = rewrite_ident(context, ident);
109 let sub_pat = match *sub_pat {
114 .checked_sub(prefix.len() + mut_infix.len() + id_str.len() + 2)?;
115 let lo = context.snippet_provider.span_after(self.span, "@");
116 combine_strs_with_missing_comments(
119 &p.rewrite(context, Shape::legacy(width, shape.indent))?,
120 mk_sp(lo, p.span.lo()),
125 None => "".to_owned(),
128 // combine prefix and mut
129 let (first_lo, first) = if !prefix.is_empty() && !mut_infix.is_empty() {
130 let hi = context.snippet_provider.span_before(self.span, "mut");
131 let lo = context.snippet_provider.span_after(self.span, "ref");
133 context.snippet_provider.span_after(self.span, "mut"),
134 combine_strs_with_missing_comments(
143 } else if !prefix.is_empty() {
145 context.snippet_provider.span_after(self.span, "ref"),
148 } else if !mut_infix.is_empty() {
150 context.snippet_provider.span_after(self.span, "mut"),
151 mut_infix.to_owned(),
154 (self.span.lo(), "".to_owned())
157 let next = if !sub_pat.is_empty() {
158 let hi = context.snippet_provider.span_before(self.span, "@");
159 combine_strs_with_missing_comments(
163 mk_sp(ident.span.hi(), hi),
171 combine_strs_with_missing_comments(
175 mk_sp(first_lo, ident.span.lo()),
181 if 1 <= shape.width {
188 if 1 <= shape.width {
189 Some("..".to_owned())
194 PatKind::Range(ref lhs, ref rhs, ref end_kind) => {
195 let infix = match end_kind.node {
196 RangeEnd::Included(RangeSyntax::DotDotDot) => "...",
197 RangeEnd::Included(RangeSyntax::DotDotEq) => "..=",
198 RangeEnd::Excluded => "..",
200 let infix = if context.config.spaces_around_ranges() {
201 let lhs_spacing = match lhs {
205 let rhs_spacing = match rhs {
209 format!("{}{}{}", lhs_spacing, infix, rhs_spacing)
216 PairParts::infix(&infix),
219 SeparatorPlace::Front,
222 PatKind::Ref(ref pat, mutability) => {
223 let prefix = format!("&{}", format_mutability(mutability));
224 rewrite_unary_prefix(context, &prefix, &**pat, shape)
226 PatKind::Tuple(ref items) => rewrite_tuple_pat(items, None, self.span, context, shape),
227 PatKind::Path(ref q_self, ref path) => {
228 rewrite_path(context, PathContext::Expr, q_self.as_ref(), path, shape)
230 PatKind::TupleStruct(ref q_self, ref path, ref pat_vec) => {
232 rewrite_path(context, PathContext::Expr, q_self.as_ref(), path, shape)?;
233 rewrite_tuple_pat(pat_vec, Some(path_str), self.span, context, shape)
235 PatKind::Lit(ref expr) => expr.rewrite(context, shape),
236 PatKind::Slice(ref slice_pat) if context.config.version() == Version::One => {
237 let rw: Vec<String> = slice_pat
240 if let Some(rw) = p.rewrite(context, shape) {
243 context.snippet(p.span).to_string()
247 Some(format!("[{}]", rw.join(", ")))
249 PatKind::Slice(ref slice_pat) => overflow::rewrite_with_square_brackets(
258 PatKind::Struct(ref qself, ref path, ref fields, ellipsis) => {
259 rewrite_struct_pat(qself, path, fields, ellipsis, self.span, context, shape)
261 PatKind::MacCall(ref mac) => {
262 rewrite_macro(mac, None, context, shape, MacroPosition::Pat)
264 PatKind::Paren(ref pat) => pat
265 .rewrite(context, shape.offset_left(1)?.sub_width(1)?)
266 .map(|inner_pat| format!("({})", inner_pat)),
271 fn rewrite_struct_pat(
272 qself: &Option<ast::QSelf>,
274 fields: &[ast::PatField],
277 context: &RewriteContext<'_>,
279 ) -> Option<String> {
281 let path_shape = shape.sub_width(2)?;
282 let path_str = rewrite_path(context, PathContext::Expr, qself.as_ref(), path, path_shape)?;
284 if fields.is_empty() && !ellipsis {
285 return Some(format!("{} {{}}", path_str));
288 let (ellipsis_str, terminator) = if ellipsis { (", ..", "..") } else { ("", "}") };
290 // 3 = ` { `, 2 = ` }`.
291 let (h_shape, v_shape) =
292 struct_lit_shape(shape, context, path_str.len() + 3, ellipsis_str.len() + 2)?;
294 let items = itemize_list(
295 context.snippet_provider,
300 if f.attrs.is_empty() {
303 f.attrs.first().unwrap().span.lo()
307 |f| f.rewrite(context, v_shape),
308 context.snippet_provider.span_after(span, "{"),
312 let item_vec = items.collect::<Vec<_>>();
314 let tactic = struct_lit_tactic(h_shape, context, &item_vec);
315 let nested_shape = shape_for_tactic(tactic, h_shape, v_shape);
316 let fmt = struct_lit_formatting(nested_shape, tactic, context, false);
318 let mut fields_str = write_list(&item_vec, &fmt)?;
319 let one_line_width = h_shape.map_or(0, |shape| shape.width);
322 if fields_str.contains('\n') || fields_str.len() > one_line_width {
323 // Add a missing trailing comma.
324 if context.config.trailing_comma() == SeparatorTactic::Never {
325 fields_str.push(',');
327 fields_str.push('\n');
328 fields_str.push_str(&nested_shape.indent.to_string(context.config));
330 if !fields_str.is_empty() {
331 // there are preceding struct fields being matched on
332 if tactic == DefinitiveListTactic::Vertical {
333 // if the tactic is Vertical, write_list already added a trailing ,
334 fields_str.push(' ');
336 fields_str.push_str(", ");
340 fields_str.push_str("..");
343 // ast::Pat doesn't have attrs so use &[]
344 let fields_str = wrap_struct_field(context, &[], &fields_str, shape, v_shape, one_line_width)?;
345 Some(format!("{} {{{}}}", path_str, fields_str))
348 impl Rewrite for PatField {
349 fn rewrite(&self, context: &RewriteContext<'_>, shape: Shape) -> Option<String> {
350 let hi_pos = if let Some(last) = self.attrs.last() {
356 let attrs_str = if self.attrs.is_empty() {
359 self.attrs.rewrite(context, shape)?
362 let pat_str = self.pat.rewrite(context, shape)?;
363 if self.is_shorthand {
364 combine_strs_with_missing_comments(
368 mk_sp(hi_pos, self.pat.span.lo()),
373 let nested_shape = shape.block_indent(context.config.tab_spaces());
374 let id_str = rewrite_ident(context, self.ident);
375 let one_line_width = id_str.len() + 2 + pat_str.len();
376 let pat_and_id_str = if one_line_width <= shape.width {
377 format!("{}: {}", id_str, pat_str)
382 nested_shape.indent.to_string(context.config),
383 self.pat.rewrite(context, nested_shape)?
386 combine_strs_with_missing_comments(
390 mk_sp(hi_pos, self.pat.span.lo()),
399 pub(crate) enum TuplePatField<'a> {
400 Pat(&'a ptr::P<ast::Pat>),
404 impl<'a> Rewrite for TuplePatField<'a> {
405 fn rewrite(&self, context: &RewriteContext<'_>, shape: Shape) -> Option<String> {
407 TuplePatField::Pat(p) => p.rewrite(context, shape),
408 TuplePatField::Dotdot(_) => Some("..".to_string()),
413 impl<'a> Spanned for TuplePatField<'a> {
414 fn span(&self) -> Span {
416 TuplePatField::Pat(p) => p.span(),
417 TuplePatField::Dotdot(span) => span,
422 impl<'a> TuplePatField<'a> {
423 fn is_dotdot(&self) -> bool {
425 TuplePatField::Pat(pat) => matches!(pat.kind, ast::PatKind::Rest),
426 TuplePatField::Dotdot(_) => true,
431 pub(crate) fn can_be_overflowed_pat(
432 context: &RewriteContext<'_>,
433 pat: &TuplePatField<'_>,
437 TuplePatField::Pat(pat) => match pat.kind {
438 ast::PatKind::Path(..)
439 | ast::PatKind::Tuple(..)
440 | ast::PatKind::Struct(..)
441 | ast::PatKind::TupleStruct(..) => context.use_block_indent() && len == 1,
442 ast::PatKind::Ref(ref p, _) | ast::PatKind::Box(ref p) => {
443 can_be_overflowed_pat(context, &TuplePatField::Pat(p), len)
445 ast::PatKind::Lit(ref expr) => can_be_overflowed_expr(context, expr, len),
448 TuplePatField::Dotdot(..) => false,
452 fn rewrite_tuple_pat(
453 pats: &[ptr::P<ast::Pat>],
454 path_str: Option<String>,
456 context: &RewriteContext<'_>,
458 ) -> Option<String> {
460 return Some(format!("{}()", path_str.unwrap_or_default()));
462 let mut pat_vec: Vec<_> = pats.iter().map(TuplePatField::Pat).collect();
464 let wildcard_suffix_len = count_wildcard_suffix_len(context, &pat_vec, span, shape);
465 let (pat_vec, span) = if context.config.condense_wildcard_suffixes() && wildcard_suffix_len >= 2
467 let new_item_count = 1 + pat_vec.len() - wildcard_suffix_len;
468 let sp = pat_vec[new_item_count - 1].span();
469 let snippet = context.snippet(sp);
470 let lo = sp.lo() + BytePos(snippet.find_uncommented("_").unwrap() as u32);
471 pat_vec[new_item_count - 1] = TuplePatField::Dotdot(mk_sp_lo_plus_one(lo));
473 &pat_vec[..new_item_count],
474 mk_sp(span.lo(), lo + BytePos(1)),
480 let is_last_pat_dotdot = pat_vec.last().map_or(false, |p| p.is_dotdot());
481 let add_comma = path_str.is_none() && pat_vec.len() == 1 && !is_last_pat_dotdot;
482 let path_str = path_str.unwrap_or_default();
484 overflow::rewrite_with_parens(
490 context.config.max_width(),
492 Some(SeparatorTactic::Always)
499 fn count_wildcard_suffix_len(
500 context: &RewriteContext<'_>,
501 patterns: &[TuplePatField<'_>],
505 let mut suffix_len = 0;
507 let items: Vec<_> = itemize_list(
508 context.snippet_provider,
512 |item| item.span().lo(),
513 |item| item.span().hi(),
514 |item| item.rewrite(context, shape),
515 context.snippet_provider.span_after(span, "("),
516 span.hi() - BytePos(1),
524 .take_while(|i| matches!(i.item, Some(ref internal_string) if internal_string == "_"))
528 if item.has_comment() {