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.
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.
11 // Formatting top-level items - functions, structs, enums, traits, impls.
18 use syntax::{abi, ast, ptr, symbol};
19 use syntax::codemap::{self, BytePos, Span};
22 use codemap::{LineRangeUtils, SpanUtils};
23 use comment::{combine_strs_with_missing_comments, contains_comment, recover_comment_removed,
24 recover_missing_comment_in_span, rewrite_missing_comment, FindUncommented};
25 use config::{BraceStyle, Config, Density, IndentStyle};
26 use expr::{format_expr, is_empty_block, is_simple_block_stmt, rewrite_assign_rhs, ExprType};
27 use lists::{definitive_tactic, itemize_list, write_list, ListFormatting, ListItem, Separator};
28 use rewrite::{Rewrite, RewriteContext};
30 use shape::{Indent, Shape};
32 use types::join_bounds;
33 use utils::{colon_spaces, contains_skip, first_line_width, format_abi, format_constness,
34 format_defaultness, format_mutability, format_unsafety, format_visibility,
35 is_attributes_extendable, last_line_contains_single_line_comment,
36 last_line_used_width, last_line_width, mk_sp, semicolon_for_expr, starts_with_newline,
37 stmt_expr, trimmed_last_line_width};
38 use vertical::rewrite_with_alignment;
39 use visitor::FmtVisitor;
41 const DEFAULT_VISIBILITY: ast::Visibility = codemap::Spanned {
42 node: ast::VisibilityKind::Inherited,
43 span: codemap::DUMMY_SP,
46 fn type_annotation_separator(config: &Config) -> &str {
47 colon_spaces(config.space_before_colon(), config.space_after_colon())
50 // Statements of the form
51 // let pat: ty = init;
52 impl Rewrite for ast::Local {
53 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
55 "Local::rewrite {:?} {} {:?}",
56 self, shape.width, shape.indent
59 skip_out_of_file_lines_range!(context, self.span);
61 if contains_skip(&self.attrs) {
65 let attrs_str = self.attrs.rewrite(context, shape)?;
66 let mut result = if attrs_str.is_empty() {
69 combine_strs_with_missing_comments(
74 self.attrs.last().map(|a| a.span.hi()).unwrap(),
83 let pat_shape = shape.offset_left(4)?;
85 let pat_shape = pat_shape.sub_width(1)?;
86 let pat_str = self.pat.rewrite(context, pat_shape)?;
87 result.push_str(&pat_str);
89 // String that is placed within the assignment pattern and expression.
91 let mut infix = String::with_capacity(32);
93 if let Some(ref ty) = self.ty {
94 let separator = type_annotation_separator(context.config);
95 let indent = shape.indent + last_line_width(&result) + separator.len();
97 let budget = shape.width.checked_sub(indent.width() + 1)?;
98 let rewrite = ty.rewrite(context, Shape::legacy(budget, indent))?;
100 infix.push_str(separator);
101 infix.push_str(&rewrite);
104 if self.init.is_some() {
105 infix.push_str(" =");
111 result.push_str(&infix);
113 if let Some(ref ex) = self.init {
114 // 1 = trailing semicolon;
115 let nested_shape = shape.sub_width(1)?;
117 result = rewrite_assign_rhs(context, result, &**ex, nested_shape)?;
125 // TODO convert to using rewrite style rather than visitor
126 // TODO format modules in this style
129 keyword: &'static str,
130 abi: Cow<'static, str>,
131 vis: Option<&'a ast::Visibility>,
132 body: Vec<BodyElement<'a>>,
137 fn from_foreign_mod(fm: &'a ast::ForeignMod, span: Span, config: &Config) -> Item<'a> {
140 abi: format_abi(fm.abi, config.force_explicit_abi(), true),
144 .map(|i| BodyElement::ForeignItem(i))
151 enum BodyElement<'a> {
152 // Stmt(&'a ast::Stmt),
153 // Field(&'a ast::Field),
154 // Variant(&'a ast::Variant),
155 // Item(&'a ast::Item),
156 ForeignItem(&'a ast::ForeignItem),
159 /// Represents a fn's signature.
160 pub struct FnSig<'a> {
161 decl: &'a ast::FnDecl,
162 generics: &'a ast::Generics,
164 constness: ast::Constness,
165 defaultness: ast::Defaultness,
166 unsafety: ast::Unsafety,
167 visibility: ast::Visibility,
172 decl: &'a ast::FnDecl,
173 generics: &'a ast::Generics,
174 vis: ast::Visibility,
180 constness: ast::Constness::NotConst,
181 defaultness: ast::Defaultness::Final,
182 unsafety: ast::Unsafety::Normal,
187 pub fn from_method_sig(
188 method_sig: &'a ast::MethodSig,
189 generics: &'a ast::Generics,
192 unsafety: method_sig.unsafety,
193 constness: method_sig.constness.node,
194 defaultness: ast::Defaultness::Final,
196 decl: &*method_sig.decl,
198 visibility: DEFAULT_VISIBILITY,
203 fn_kind: &'a visit::FnKind,
204 generics: &'a ast::Generics,
205 decl: &'a ast::FnDecl,
206 defualtness: ast::Defaultness,
209 visit::FnKind::ItemFn(_, unsafety, constness, abi, visibility, _) => FnSig {
213 constness: constness.node,
214 defaultness: defualtness,
216 visibility: visibility.clone(),
218 visit::FnKind::Method(_, method_sig, vis, _) => {
219 let mut fn_sig = FnSig::from_method_sig(method_sig, generics);
220 fn_sig.defaultness = defualtness;
221 if let Some(vis) = vis {
222 fn_sig.visibility = vis.clone();
230 fn to_str(&self, context: &RewriteContext) -> String {
231 let mut result = String::with_capacity(128);
232 // Vis defaultness constness unsafety abi.
233 result.push_str(&*format_visibility(&self.visibility));
234 result.push_str(format_defaultness(self.defaultness));
235 result.push_str(format_constness(self.constness));
236 result.push_str(format_unsafety(self.unsafety));
237 result.push_str(&format_abi(
239 context.config.force_explicit_abi(),
246 impl<'a> FmtVisitor<'a> {
247 fn format_item(&mut self, item: &Item) {
248 self.buffer.push_str(&item.abi);
250 let snippet = self.snippet(item.span);
251 let brace_pos = snippet.find_uncommented("{").unwrap();
254 if !item.body.is_empty() || contains_comment(&snippet[brace_pos..]) {
255 // FIXME: this skips comments between the extern keyword and the opening
257 self.last_pos = item.span.lo() + BytePos(brace_pos as u32 + 1);
258 self.block_indent = self.block_indent.block_indent(self.config);
260 if item.body.is_empty() {
261 self.format_missing_no_indent(item.span.hi() - BytePos(1));
262 self.block_indent = self.block_indent.block_unindent(self.config);
263 let indent_str = self.block_indent.to_string(self.config);
264 self.push_str(&indent_str);
266 for item in &item.body {
267 self.format_body_element(item);
270 self.block_indent = self.block_indent.block_unindent(self.config);
271 self.format_missing_with_indent(item.span.hi() - BytePos(1));
276 self.last_pos = item.span.hi();
279 fn format_body_element(&mut self, element: &BodyElement) {
281 BodyElement::ForeignItem(item) => self.format_foreign_item(item),
285 pub fn format_foreign_mod(&mut self, fm: &ast::ForeignMod, span: Span) {
286 let item = Item::from_foreign_mod(fm, span, self.config);
287 self.format_item(&item);
290 fn format_foreign_item(&mut self, item: &ast::ForeignItem) {
291 let rewrite = item.rewrite(&self.get_context(), self.shape());
292 self.push_rewrite(item.span(), rewrite);
293 self.last_pos = item.span.hi();
303 ) -> Option<String> {
304 let context = self.get_context();
306 let mut newline_brace = newline_for_brace(self.config, &fn_sig.generics.where_clause);
308 let (mut result, force_newline_brace) =
309 rewrite_fn_base(&context, indent, ident, fn_sig, span, newline_brace, true)?;
312 if self.config.brace_style() == BraceStyle::AlwaysNextLine || force_newline_brace
313 || last_line_width(&result) + 2 > self.shape().width
315 newline_brace = true;
316 } else if !result.contains('\n') {
317 newline_brace = false;
320 // Prepare for the function body by possibly adding a newline and
322 // FIXME we'll miss anything between the end of the signature and the
323 // start of the body, but we need more spans from the compiler to solve
326 result.push_str(&indent.to_string_with_newline(self.config));
331 self.single_line_fn(&result, block).or_else(|| Some(result))
334 pub fn rewrite_required_fn(
338 sig: &ast::MethodSig,
339 generics: &ast::Generics,
341 ) -> Option<String> {
342 // Drop semicolon or it will be interpreted as comment.
343 let span = mk_sp(span.lo(), span.hi() - BytePos(1));
344 let context = self.get_context();
346 let (mut result, _) = rewrite_fn_base(
350 &FnSig::from_method_sig(sig, generics),
356 // Re-attach semicolon
362 fn single_line_fn(&self, fn_str: &str, block: &ast::Block) -> Option<String> {
363 if fn_str.contains('\n') {
367 let codemap = self.get_context().codemap;
369 if self.config.empty_item_single_line() && is_empty_block(block, codemap)
370 && self.block_indent.width() + fn_str.len() + 2 <= self.config.max_width()
372 return Some(format!("{}{{}}", fn_str));
375 if self.config.fn_single_line() && is_simple_block_stmt(block, codemap) {
377 if let Some(stmt) = block.stmts.first() {
378 match stmt_expr(stmt) {
380 let suffix = if semicolon_for_expr(&self.get_context(), e) {
386 format_expr(e, ExprType::Statement, &self.get_context(), self.shape())
388 .or_else(|| Some(self.snippet(e.span).to_owned()))
390 None => stmt.rewrite(&self.get_context(), self.shape()),
397 if let Some(res) = rewrite {
398 let width = self.block_indent.width() + fn_str.len() + res.len() + 4;
399 if !res.contains('\n') && width <= self.config.max_width() {
400 return Some(format!("{}{{ {} }}", fn_str, res));
408 pub fn visit_static(&mut self, static_parts: &StaticParts) {
409 let rewrite = rewrite_static(&self.get_context(), static_parts, self.block_indent);
410 self.push_rewrite(static_parts.span, rewrite);
413 pub fn visit_struct(&mut self, struct_parts: &StructParts) {
414 let is_tuple = struct_parts.def.is_tuple();
415 let rewrite = format_struct(&self.get_context(), struct_parts, self.block_indent, None)
416 .map(|s| if is_tuple { s + ";" } else { s });
417 self.push_rewrite(struct_parts.span, rewrite);
423 vis: &ast::Visibility,
424 enum_def: &ast::EnumDef,
425 generics: &ast::Generics,
428 let enum_header = format_header("enum ", ident, vis);
429 self.push_str(&enum_header);
431 let enum_snippet = self.snippet(span);
432 let brace_pos = enum_snippet.find_uncommented("{").unwrap();
433 let body_start = span.lo() + BytePos(brace_pos as u32 + 1);
434 let generics_str = format_generics(
437 self.config.brace_style(),
438 if enum_def.variants.is_empty() {
439 BracePos::ForceSameLine
444 mk_sp(span.lo(), body_start),
445 last_line_width(&enum_header),
447 self.push_str(&generics_str);
449 self.last_pos = body_start;
451 self.block_indent = self.block_indent.block_indent(self.config);
452 let variant_list = self.format_variant_list(enum_def, body_start, span.hi() - BytePos(1));
454 Some(ref body_str) => self.push_str(body_str),
455 None => self.format_missing_no_indent(span.hi() - BytePos(1)),
457 self.block_indent = self.block_indent.block_unindent(self.config);
459 if variant_list.is_some() || contains_comment(&enum_snippet[brace_pos..]) {
460 let indent_str = self.block_indent.to_string(self.config);
461 self.push_str(&indent_str);
464 self.last_pos = span.hi();
467 // Format the body of an enum definition
468 fn format_variant_list(
470 enum_def: &ast::EnumDef,
473 ) -> Option<String> {
474 if enum_def.variants.is_empty() {
477 let mut result = String::with_capacity(1024);
478 let indentation = self.block_indent.to_string_with_newline(self.config);
479 result.push_str(&indentation);
481 let itemize_list_with = |one_line_width: usize| {
483 self.snippet_provider,
484 enum_def.variants.iter(),
488 if !f.node.attrs.is_empty() {
489 f.node.attrs[0].span.lo()
495 |f| self.format_variant(f, one_line_width),
501 let mut items: Vec<_> =
502 itemize_list_with(self.config.width_heuristics().struct_variant_width);
503 // If one of the variants use multiple lines, use multi-lined formatting for all variants.
504 let has_multiline_variant = items.iter().any(|item| item.inner_as_ref().contains('\n'));
505 let has_single_line_variant = items.iter().any(|item| !item.inner_as_ref().contains('\n'));
506 if has_multiline_variant && has_single_line_variant {
507 items = itemize_list_with(0);
510 let shape = self.shape().sub_width(2)?;
511 let fmt = ListFormatting {
512 tactic: DefinitiveListTactic::Vertical,
514 trailing_separator: self.config.trailing_comma(),
515 separator_place: SeparatorPlace::Back,
517 ends_with_newline: true,
518 preserve_newline: true,
522 let list = write_list(&items, &fmt)?;
523 result.push_str(&list);
528 // Variant of an enum.
529 fn format_variant(&self, field: &ast::Variant, one_line_width: usize) -> Option<String> {
530 if contains_skip(&field.node.attrs) {
531 let lo = field.node.attrs[0].span.lo();
532 let span = mk_sp(lo, field.span.hi());
533 return Some(self.snippet(span).to_owned());
536 let context = self.get_context();
538 let shape = self.shape().sub_width(1)?;
539 let attrs_str = field.node.attrs.rewrite(&context, shape)?;
544 .map_or(field.span.lo(), |attr| attr.span.hi());
545 let span = mk_sp(lo, field.span.lo());
547 let variant_body = match field.node.data {
548 ast::VariantData::Tuple(..) | ast::VariantData::Struct(..) => format_struct(
550 &StructParts::from_variant(field),
552 Some(one_line_width),
554 ast::VariantData::Unit(..) => {
555 if let Some(ref expr) = field.node.disr_expr {
556 let lhs = format!("{} =", field.node.name);
557 rewrite_assign_rhs(&context, lhs, &**expr, shape)?
559 field.node.name.to_string()
564 combine_strs_with_missing_comments(&context, &attrs_str, &variant_body, span, shape, false)
569 context: &RewriteContext,
572 where_span_end: Option<BytePos>,
573 ) -> Option<String> {
574 if let ast::ItemKind::Impl(_, _, _, ref generics, _, ref self_ty, ref items) = item.node {
575 let mut result = String::with_capacity(128);
576 let ref_and_type = format_impl_ref_and_type(context, item, offset)?;
577 let sep = offset.to_string_with_newline(context.config);
578 result.push_str(&ref_and_type);
580 let where_budget = if result.contains('\n') {
581 context.config.max_width()
583 context.budget(last_line_width(&result))
585 let option = WhereClauseOption::snuggled(&ref_and_type);
586 let where_clause_str = rewrite_where_clause(
588 &generics.where_clause,
589 context.config.brace_style(),
590 Shape::legacy(where_budget, offset.block_only()),
599 // If there is no where clause, we may have missing comments between the trait name and
600 // the opening brace.
601 if generics.where_clause.predicates.is_empty() {
602 if let Some(hi) = where_span_end {
603 match recover_missing_comment_in_span(
604 mk_sp(self_ty.span.hi(), hi),
605 Shape::indented(offset, context.config),
607 last_line_width(&result),
609 Some(ref missing_comment) if !missing_comment.is_empty() => {
610 result.push_str(missing_comment);
617 if is_impl_single_line(context, items, &result, &where_clause_str, item)? {
618 result.push_str(&where_clause_str);
619 if where_clause_str.contains('\n') || last_line_contains_single_line_comment(&result) {
620 result.push_str(&format!("{}{{{}}}", &sep, &sep));
622 result.push_str(" {}");
627 if !where_clause_str.is_empty() && !where_clause_str.contains('\n') {
628 let width = offset.block_indent + context.config.tab_spaces() - 1;
629 let where_indent = Indent::new(0, width);
630 result.push_str(&where_indent.to_string_with_newline(context.config));
632 result.push_str(&where_clause_str);
634 let need_newline = last_line_contains_single_line_comment(&result) || result.contains('\n');
635 match context.config.brace_style() {
636 _ if need_newline => result.push_str(&sep),
637 BraceStyle::AlwaysNextLine => result.push_str(&sep),
638 BraceStyle::PreferSameLine => result.push(' '),
639 BraceStyle::SameLineWhere => {
640 if !where_clause_str.is_empty() {
641 result.push_str(&sep);
650 let snippet = context.snippet(item.span);
651 let open_pos = snippet.find_uncommented("{")? + 1;
653 if !items.is_empty() || contains_comment(&snippet[open_pos..]) {
654 let mut visitor = FmtVisitor::from_context(context);
655 visitor.block_indent = offset.block_only().block_indent(context.config);
656 visitor.last_pos = item.span.lo() + BytePos(open_pos as u32);
658 visitor.visit_attrs(&item.attrs, ast::AttrStyle::Inner);
660 visitor.visit_impl_item(item);
663 visitor.format_missing(item.span.hi() - BytePos(1));
665 let inner_indent_str = visitor.block_indent.to_string_with_newline(context.config);
666 let outer_indent_str = offset.block_only().to_string_with_newline(context.config);
668 result.push_str(&inner_indent_str);
669 result.push_str(visitor.buffer.to_string().trim());
670 result.push_str(&outer_indent_str);
673 if result.ends_with('{') {
674 result.push_str(&sep);
684 fn is_impl_single_line(
685 context: &RewriteContext,
686 items: &[ast::ImplItem],
688 where_clause_str: &str,
691 let snippet = context.snippet(item.span);
692 let open_pos = snippet.find_uncommented("{")? + 1;
695 context.config.empty_item_single_line() && items.is_empty() && !result.contains('\n')
696 && result.len() + where_clause_str.len() <= context.config.max_width()
697 && !contains_comment(&snippet[open_pos..]),
701 fn format_impl_ref_and_type(
702 context: &RewriteContext,
705 ) -> Option<String> {
706 if let ast::ItemKind::Impl(
716 let mut result = String::with_capacity(128);
718 result.push_str(&format_visibility(&item.vis));
719 result.push_str(format_defaultness(defaultness));
720 result.push_str(format_unsafety(unsafety));
722 let lo = context.snippet_provider.span_after(item.span, "impl");
723 let hi = match *trait_ref {
724 Some(ref tr) => tr.path.span.lo(),
725 None => self_ty.span.lo(),
727 let shape = generics_shape_from_config(
729 Shape::indented(offset + last_line_width(&result), context.config),
732 let generics_str = rewrite_generics(context, "impl", generics, shape, mk_sp(lo, hi))?;
733 result.push_str(&generics_str);
735 let polarity_str = if polarity == ast::ImplPolarity::Negative {
741 if let Some(ref trait_ref) = *trait_ref {
742 let result_len = last_line_width(&result);
743 result.push_str(&rewrite_trait_ref(
752 // Try to put the self type in a single line.
754 let trait_ref_overhead = if trait_ref.is_some() { 4 } else { 0 };
755 let curly_brace_overhead = if generics.where_clause.predicates.is_empty() {
756 // If there is no where clause adapt budget for type formatting to take space and curly
757 // brace into account.
758 match context.config.brace_style() {
759 BraceStyle::AlwaysNextLine => 0,
765 let used_space = last_line_width(&result) + trait_ref_overhead + curly_brace_overhead;
766 // 1 = space before the type.
767 let budget = context.budget(used_space + 1);
768 if let Some(self_ty_str) = self_ty.rewrite(context, Shape::legacy(budget, offset)) {
769 if !self_ty_str.contains('\n') {
770 if trait_ref.is_some() {
771 result.push_str(" for ");
775 result.push_str(&self_ty_str);
780 // Couldn't fit the self type on a single line, put it on a new line.
782 // Add indentation of one additional tab.
783 let new_line_offset = offset.block_indent(context.config);
784 result.push_str(&new_line_offset.to_string(context.config));
785 if trait_ref.is_some() {
786 result.push_str("for ");
788 let budget = context.budget(last_line_width(&result));
789 let type_offset = match context.config.indent_style() {
790 IndentStyle::Visual => new_line_offset + trait_ref_overhead,
791 IndentStyle::Block => new_line_offset,
793 result.push_str(&*self_ty.rewrite(context, Shape::legacy(budget, type_offset))?);
800 fn rewrite_trait_ref(
801 context: &RewriteContext,
802 trait_ref: &ast::TraitRef,
806 ) -> Option<String> {
807 // 1 = space between generics and trait_ref
808 let used_space = 1 + polarity_str.len() + result_len;
809 let shape = Shape::indented(offset + used_space, context.config);
810 if let Some(trait_ref_str) = trait_ref.rewrite(context, shape) {
811 if !trait_ref_str.contains('\n') {
812 return Some(format!(" {}{}", polarity_str, &trait_ref_str));
815 // We could not make enough space for trait_ref, so put it on new line.
816 let offset = offset.block_indent(context.config);
817 let shape = Shape::indented(offset, context.config);
818 let trait_ref_str = trait_ref.rewrite(context, shape)?;
821 &offset.to_string_with_newline(context.config),
827 pub struct StructParts<'a> {
830 vis: &'a ast::Visibility,
831 def: &'a ast::VariantData,
832 generics: Option<&'a ast::Generics>,
836 impl<'a> StructParts<'a> {
837 fn format_header(&self) -> String {
838 format_header(self.prefix, self.ident, self.vis)
841 fn from_variant(variant: &'a ast::Variant) -> Self {
844 ident: variant.node.name,
845 vis: &DEFAULT_VISIBILITY,
846 def: &variant.node.data,
852 pub fn from_item(item: &'a ast::Item) -> Self {
853 let (prefix, def, generics) = match item.node {
854 ast::ItemKind::Struct(ref def, ref generics) => ("struct ", def, generics),
855 ast::ItemKind::Union(ref def, ref generics) => ("union ", def, generics),
863 generics: Some(generics),
870 context: &RewriteContext,
871 struct_parts: &StructParts,
873 one_line_width: Option<usize>,
874 ) -> Option<String> {
875 match *struct_parts.def {
876 ast::VariantData::Unit(..) => format_unit_struct(context, struct_parts, offset),
877 ast::VariantData::Tuple(ref fields, _) => {
878 format_tuple_struct(context, struct_parts, fields, offset)
880 ast::VariantData::Struct(ref fields, _) => {
881 format_struct_struct(context, struct_parts, fields, offset, one_line_width)
886 pub fn format_trait(context: &RewriteContext, item: &ast::Item, offset: Indent) -> Option<String> {
887 if let ast::ItemKind::Trait(_, unsafety, ref generics, ref type_param_bounds, ref trait_items) =
890 let mut result = String::with_capacity(128);
891 let header = format!(
893 format_visibility(&item.vis),
894 format_unsafety(unsafety),
897 result.push_str(&header);
899 let body_lo = context.snippet_provider.span_after(item.span, "{");
901 let shape = Shape::indented(offset, context.config).offset_left(result.len())?;
902 let generics_str = rewrite_generics(
904 &item.ident.to_string(),
907 mk_sp(item.span.lo(), body_lo),
909 result.push_str(&generics_str);
911 // FIXME(#2055): rustfmt fails to format when there are comments between trait bounds.
912 if !type_param_bounds.is_empty() {
913 let ident_hi = context
915 .span_after(item.span, &format!("{}", item.ident));
916 let bound_hi = type_param_bounds.last().unwrap().span().hi();
917 let snippet = context.snippet(mk_sp(ident_hi, bound_hi));
918 if contains_comment(snippet) {
922 let trait_bound_str = rewrite_trait_bounds(
925 Shape::indented(offset, context.config),
927 // If the trait, generics, and trait bound cannot fit on the same line,
928 // put the trait bounds on an indented new line
929 if offset.width() + last_line_width(&result) + trait_bound_str.len()
930 > context.config.comment_width()
932 let trait_indent = offset.block_only().block_indent(context.config);
933 result.push_str(&trait_indent.to_string_with_newline(context.config));
935 result.push_str(&trait_bound_str);
938 if context.config.indent_style() == IndentStyle::Block && result.is_empty() {
944 let where_budget = context.budget(last_line_width(&result));
945 let pos_before_where = if type_param_bounds.is_empty() {
946 generics.where_clause.span.lo()
948 type_param_bounds[type_param_bounds.len() - 1].span().hi()
950 let option = WhereClauseOption::snuggled(&generics_str);
951 let where_clause_str = rewrite_where_clause(
953 &generics.where_clause,
954 context.config.brace_style(),
955 Shape::legacy(where_budget, offset.block_only()),
963 // If the where clause cannot fit on the same line,
964 // put the where clause on a new line
965 if !where_clause_str.contains('\n')
966 && last_line_width(&result) + where_clause_str.len() + offset.width()
967 > context.config.comment_width()
969 let width = offset.block_indent + context.config.tab_spaces() - 1;
970 let where_indent = Indent::new(0, width);
971 result.push_str(&where_indent.to_string_with_newline(context.config));
973 result.push_str(&where_clause_str);
975 if generics.where_clause.predicates.is_empty() {
976 let item_snippet = context.snippet(item.span);
977 if let Some(lo) = item_snippet.chars().position(|c| c == '/') {
979 let comment_hi = body_lo - BytePos(1);
980 let comment_lo = item.span.lo() + BytePos(lo as u32);
981 if comment_lo < comment_hi {
982 match recover_missing_comment_in_span(
983 mk_sp(comment_lo, comment_hi),
984 Shape::indented(offset, context.config),
986 last_line_width(&result),
988 Some(ref missing_comment) if !missing_comment.is_empty() => {
989 result.push_str(missing_comment);
997 match context.config.brace_style() {
998 _ if last_line_contains_single_line_comment(&result) => {
999 result.push_str(&offset.to_string_with_newline(context.config));
1001 BraceStyle::AlwaysNextLine => {
1002 result.push_str(&offset.to_string_with_newline(context.config));
1004 BraceStyle::PreferSameLine => result.push(' '),
1005 BraceStyle::SameLineWhere => {
1006 if !where_clause_str.is_empty()
1007 && (!trait_items.is_empty() || result.contains('\n'))
1009 result.push_str(&offset.to_string_with_newline(context.config));
1017 let snippet = context.snippet(item.span);
1018 let open_pos = snippet.find_uncommented("{")? + 1;
1020 if !trait_items.is_empty() || contains_comment(&snippet[open_pos..]) {
1021 let mut visitor = FmtVisitor::from_context(context);
1022 visitor.block_indent = offset.block_only().block_indent(context.config);
1023 visitor.last_pos = item.span.lo() + BytePos(open_pos as u32);
1025 for item in trait_items {
1026 visitor.visit_trait_item(item);
1029 visitor.format_missing(item.span.hi() - BytePos(1));
1031 let inner_indent_str = visitor.block_indent.to_string_with_newline(context.config);
1032 let outer_indent_str = offset.block_only().to_string_with_newline(context.config);
1034 result.push_str(&inner_indent_str);
1035 result.push_str(visitor.buffer.to_string().trim());
1036 result.push_str(&outer_indent_str);
1037 } else if result.contains('\n') {
1048 pub fn format_trait_alias(
1049 context: &RewriteContext,
1051 generics: &ast::Generics,
1052 ty_param_bounds: &ast::TyParamBounds,
1054 ) -> Option<String> {
1055 let alias = ident.name.as_str();
1056 // 6 = "trait ", 2 = " ="
1057 let g_shape = shape.offset_left(6)?.sub_width(2)?;
1058 let generics_str = rewrite_generics(context, &alias, generics, g_shape, generics.span)?;
1059 let lhs = format!("trait {} =", generics_str);
1061 rewrite_assign_rhs(context, lhs, ty_param_bounds, shape.sub_width(1)?).map(|s| s + ";")
1064 fn format_unit_struct(context: &RewriteContext, p: &StructParts, offset: Indent) -> Option<String> {
1065 let header_str = format_header(p.prefix, p.ident, p.vis);
1066 let generics_str = if let Some(generics) = p.generics {
1067 let hi = if generics.where_clause.predicates.is_empty() {
1070 generics.where_clause.span.hi()
1075 context.config.brace_style(),
1078 mk_sp(generics.span.lo(), hi),
1079 last_line_width(&header_str),
1084 Some(format!("{}{};", header_str, generics_str))
1087 pub fn format_struct_struct(
1088 context: &RewriteContext,
1089 struct_parts: &StructParts,
1090 fields: &[ast::StructField],
1092 one_line_width: Option<usize>,
1093 ) -> Option<String> {
1094 let mut result = String::with_capacity(1024);
1095 let span = struct_parts.span;
1097 let header_str = struct_parts.format_header();
1098 result.push_str(&header_str);
1100 let header_hi = span.lo() + BytePos(header_str.len() as u32);
1101 let body_lo = context.snippet_provider.span_after(span, "{");
1103 let generics_str = match struct_parts.generics {
1104 Some(g) => format_generics(
1107 context.config.brace_style(),
1108 if fields.is_empty() {
1109 BracePos::ForceSameLine
1114 mk_sp(header_hi, body_lo),
1115 last_line_width(&result),
1118 // 3 = ` {}`, 2 = ` {`.
1119 let overhead = if fields.is_empty() { 3 } else { 2 };
1120 if (context.config.brace_style() == BraceStyle::AlwaysNextLine && !fields.is_empty())
1121 || context.config.max_width() < overhead + result.len()
1123 format!("\n{}{{", offset.block_only().to_string(context.config))
1130 let overhead = if fields.is_empty() { 1 } else { 0 };
1131 let total_width = result.len() + generics_str.len() + overhead;
1132 if !generics_str.is_empty() && !generics_str.contains('\n')
1133 && total_width > context.config.max_width()
1136 result.push_str(&offset.to_string(context.config));
1137 result.push_str(generics_str.trim_left());
1139 result.push_str(&generics_str);
1142 if fields.is_empty() {
1143 let snippet = context.snippet(mk_sp(body_lo, span.hi() - BytePos(1)));
1144 if snippet.trim().is_empty() {
1146 } else if snippet.trim_right_matches(&[' ', '\t'][..]).ends_with('\n') {
1148 result.push_str(snippet.trim_right());
1150 result.push_str(&offset.to_string(context.config));
1152 result.push_str(snippet);
1155 return Some(result);
1159 let one_line_budget = context.budget(result.len() + 3 + offset.width());
1160 let one_line_budget =
1161 one_line_width.map_or(0, |one_line_width| min(one_line_width, one_line_budget));
1163 let items_str = rewrite_with_alignment(
1166 Shape::indented(offset, context.config).sub_width(1)?,
1167 mk_sp(body_lo, span.hi()),
1171 if !items_str.contains('\n') && !result.contains('\n') && items_str.len() <= one_line_budget
1172 && !last_line_contains_single_line_comment(&items_str)
1174 Some(format!("{} {} }}", result, items_str))
1180 .block_indent(context.config)
1181 .to_string(context.config),
1183 offset.to_string(context.config)
1188 fn get_bytepos_after_visibility(vis: &ast::Visibility, default_span: Span) -> BytePos {
1190 ast::VisibilityKind::Crate(..) | ast::VisibilityKind::Restricted { .. } => vis.span.hi(),
1191 _ => default_span.lo(),
1195 fn format_tuple_struct(
1196 context: &RewriteContext,
1197 struct_parts: &StructParts,
1198 fields: &[ast::StructField],
1200 ) -> Option<String> {
1201 let mut result = String::with_capacity(1024);
1202 let span = struct_parts.span;
1204 let header_str = struct_parts.format_header();
1205 result.push_str(&header_str);
1207 let body_lo = if fields.is_empty() {
1208 let lo = get_bytepos_after_visibility(struct_parts.vis, span);
1211 .span_after(mk_sp(lo, span.hi()), "(")
1215 let body_hi = if fields.is_empty() {
1218 .span_after(mk_sp(body_lo, span.hi()), ")")
1220 // This is a dirty hack to work around a missing `)` from the span of the last field.
1221 let last_arg_span = fields[fields.len() - 1].span;
1222 if context.snippet(last_arg_span).ends_with(')') {
1227 .span_after(mk_sp(last_arg_span.hi(), span.hi()), ")")
1231 let where_clause_str = match struct_parts.generics {
1233 let budget = context.budget(last_line_width(&header_str));
1234 let shape = Shape::legacy(budget, offset);
1235 let g_span = mk_sp(span.lo(), body_lo);
1236 let generics_str = rewrite_generics(context, "", generics, shape, g_span)?;
1237 result.push_str(&generics_str);
1239 let where_budget = context.budget(last_line_width(&result));
1240 let option = WhereClauseOption::new(true, false);
1241 rewrite_where_clause(
1243 &generics.where_clause,
1244 context.config.brace_style(),
1245 Shape::legacy(where_budget, offset.block_only()),
1246 Density::Compressed,
1254 None => "".to_owned(),
1257 if fields.is_empty() {
1259 let used_width = last_line_used_width(&result, offset.width()) + 3;
1260 if used_width > context.config.max_width() {
1262 result.push_str(&offset
1263 .block_indent(context.config)
1264 .to_string(context.config))
1267 let snippet = context.snippet(mk_sp(
1271 .span_before(mk_sp(body_lo, span.hi()), ")"),
1273 if snippet.is_empty() {
1275 } else if snippet.trim_right_matches(&[' ', '\t'][..]).ends_with('\n') {
1276 result.push_str(snippet.trim_right());
1278 result.push_str(&offset.to_string(context.config));
1280 result.push_str(snippet);
1284 let shape = Shape::indented(offset, context.config).sub_width(1)?;
1285 let fields = &fields.iter().collect::<Vec<_>>()[..];
1286 result = overflow::rewrite_with_parens(
1292 context.config.width_heuristics().fn_call_width,
1297 if !where_clause_str.is_empty() && !where_clause_str.contains('\n')
1298 && (result.contains('\n')
1299 || offset.block_indent + result.len() + where_clause_str.len() + 1
1300 > context.config.max_width())
1302 // We need to put the where clause on a new line, but we didn't
1303 // know that earlier, so the where clause will not be indented properly.
1306 .push_str(&(offset.block_only() + (context.config.tab_spaces() - 1))
1307 .to_string(context.config));
1309 result.push_str(&where_clause_str);
1314 pub fn rewrite_type_alias(
1315 context: &RewriteContext,
1319 generics: &ast::Generics,
1320 vis: &ast::Visibility,
1322 ) -> Option<String> {
1323 let mut result = String::with_capacity(128);
1325 result.push_str(&format_visibility(vis));
1326 result.push_str("type ");
1329 let g_shape = Shape::indented(indent, context.config)
1330 .offset_left(result.len())?
1333 context.snippet_provider.span_after(span, "type"),
1336 let generics_str = rewrite_generics(context, &ident.to_string(), generics, g_shape, g_span)?;
1337 result.push_str(&generics_str);
1339 let where_budget = context.budget(last_line_width(&result));
1340 let option = WhereClauseOption::snuggled(&result);
1341 let where_clause_str = rewrite_where_clause(
1343 &generics.where_clause,
1344 context.config.brace_style(),
1345 Shape::legacy(where_budget, indent),
1353 result.push_str(&where_clause_str);
1354 if where_clause_str.is_empty() {
1355 result.push_str(" =");
1357 result.push_str(&format!(
1359 indent.to_string_with_newline(context.config)
1364 let ty_shape = Shape::indented(indent, context.config).sub_width(1)?;
1365 rewrite_assign_rhs(context, result, ty, ty_shape).map(|s| s + ";")
1368 fn type_annotation_spacing(config: &Config) -> (&str, &str) {
1370 if config.space_before_colon() { " " } else { "" },
1371 if config.space_after_colon() { " " } else { "" },
1375 pub fn rewrite_struct_field_prefix(
1376 context: &RewriteContext,
1377 field: &ast::StructField,
1378 ) -> Option<String> {
1379 let vis = format_visibility(&field.vis);
1380 let type_annotation_spacing = type_annotation_spacing(context.config);
1381 Some(match field.ident {
1382 Some(name) => format!("{}{}{}:", vis, name, type_annotation_spacing.0),
1383 None => format!("{}", vis),
1387 impl Rewrite for ast::StructField {
1388 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
1389 rewrite_struct_field(context, self, shape, 0)
1393 pub fn rewrite_struct_field(
1394 context: &RewriteContext,
1395 field: &ast::StructField,
1397 lhs_max_width: usize,
1398 ) -> Option<String> {
1399 if contains_skip(&field.attrs) {
1400 return Some(context.snippet(field.span()).to_owned());
1403 let type_annotation_spacing = type_annotation_spacing(context.config);
1404 let prefix = rewrite_struct_field_prefix(context, field)?;
1406 let attrs_str = field.attrs.rewrite(context, shape)?;
1407 let attrs_extendable = field.ident.is_none() && is_attributes_extendable(&attrs_str);
1408 let missing_span = if field.attrs.is_empty() {
1409 mk_sp(field.span.lo(), field.span.lo())
1411 mk_sp(field.attrs.last().unwrap().span.hi(), field.span.lo())
1413 let mut spacing = String::from(if field.ident.is_some() {
1414 type_annotation_spacing.1
1418 // Try to put everything on a single line.
1419 let attr_prefix = combine_strs_with_missing_comments(
1427 let overhead = last_line_width(&attr_prefix);
1428 let lhs_offset = lhs_max_width.checked_sub(overhead).unwrap_or(0);
1429 for _ in 0..lhs_offset {
1432 // In this extreme case we will be missing a space betweeen an attribute and a field.
1433 if prefix.is_empty() && !attrs_str.is_empty() && attrs_extendable && spacing.is_empty() {
1437 .offset_left(overhead + spacing.len())
1438 .and_then(|ty_shape| field.ty.rewrite(context, ty_shape));
1439 if let Some(ref ty) = orig_ty {
1440 if !ty.contains('\n') {
1441 return Some(attr_prefix + &spacing + ty);
1445 let is_prefix_empty = prefix.is_empty();
1446 // We must use multiline. We are going to put attributes and a field on different lines.
1447 let field_str = rewrite_assign_rhs(context, prefix, &*field.ty, shape)?;
1448 // Remove a leading white-space from `rewrite_assign_rhs()` when rewriting a tuple struct.
1449 let field_str = if is_prefix_empty {
1450 field_str.trim_left()
1454 combine_strs_with_missing_comments(context, &attrs_str, field_str, missing_span, shape, false)
1457 pub struct StaticParts<'a> {
1459 vis: &'a ast::Visibility,
1462 mutability: ast::Mutability,
1463 expr_opt: Option<&'a ptr::P<ast::Expr>>,
1464 defaultness: Option<ast::Defaultness>,
1468 impl<'a> StaticParts<'a> {
1469 pub fn from_item(item: &'a ast::Item) -> Self {
1470 let (prefix, ty, mutability, expr) = match item.node {
1471 ast::ItemKind::Static(ref ty, mutability, ref expr) => ("static", ty, mutability, expr),
1472 ast::ItemKind::Const(ref ty, ref expr) => {
1473 ("const", ty, ast::Mutability::Immutable, expr)
1475 _ => unreachable!(),
1483 expr_opt: Some(expr),
1489 pub fn from_trait_item(ti: &'a ast::TraitItem) -> Self {
1490 let (ty, expr_opt) = match ti.node {
1491 ast::TraitItemKind::Const(ref ty, ref expr_opt) => (ty, expr_opt),
1492 _ => unreachable!(),
1496 vis: &DEFAULT_VISIBILITY,
1499 mutability: ast::Mutability::Immutable,
1500 expr_opt: expr_opt.as_ref(),
1506 pub fn from_impl_item(ii: &'a ast::ImplItem) -> Self {
1507 let (ty, expr) = match ii.node {
1508 ast::ImplItemKind::Const(ref ty, ref expr) => (ty, expr),
1509 _ => unreachable!(),
1516 mutability: ast::Mutability::Immutable,
1517 expr_opt: Some(expr),
1518 defaultness: Some(ii.defaultness),
1525 context: &RewriteContext,
1526 static_parts: &StaticParts,
1528 ) -> Option<String> {
1529 let colon = colon_spaces(
1530 context.config.space_before_colon(),
1531 context.config.space_after_colon(),
1533 let mut prefix = format!(
1535 format_visibility(static_parts.vis),
1536 static_parts.defaultness.map_or("", format_defaultness),
1537 static_parts.prefix,
1538 format_mutability(static_parts.mutability),
1544 Shape::indented(offset.block_only(), context.config).offset_left(prefix.len() + 2)?;
1545 let ty_str = match static_parts.ty.rewrite(context, ty_shape) {
1546 Some(ty_str) => ty_str,
1548 if prefix.ends_with(' ') {
1551 let nested_indent = offset.block_indent(context.config);
1552 let nested_shape = Shape::indented(nested_indent, context.config);
1553 let ty_str = static_parts.ty.rewrite(context, nested_shape)?;
1556 nested_indent.to_string_with_newline(context.config),
1562 if let Some(expr) = static_parts.expr_opt {
1563 let lhs = format!("{}{} =", prefix, ty_str);
1565 let remaining_width = context.budget(offset.block_indent + 1);
1570 Shape::legacy(remaining_width, offset.block_only()),
1571 ).and_then(|res| recover_comment_removed(res, static_parts.span, context))
1572 .map(|s| if s.ends_with(';') { s } else { s + ";" })
1574 Some(format!("{}{};", prefix, ty_str))
1578 pub fn rewrite_associated_type(
1580 ty_opt: Option<&ptr::P<ast::Ty>>,
1581 ty_param_bounds_opt: Option<&ast::TyParamBounds>,
1582 context: &RewriteContext,
1584 ) -> Option<String> {
1585 let prefix = format!("type {}", ident);
1587 let type_bounds_str = if let Some(bounds) = ty_param_bounds_opt {
1589 let shape = Shape::indented(indent, context.config).offset_left(prefix.len() + 2)?;
1590 let bound_str = bounds
1592 .map(|ty_bound| ty_bound.rewrite(context, shape))
1593 .collect::<Option<Vec<_>>>()?;
1594 if !bounds.is_empty() {
1595 format!(": {}", join_bounds(context, shape, &bound_str))
1603 if let Some(ty) = ty_opt {
1605 let shape = Shape::indented(indent, context.config).sub_width(1)?;
1606 let lhs = format!("{}{} =", prefix, type_bounds_str);
1607 rewrite_assign_rhs(context, lhs, &**ty, shape).map(|s| s + ";")
1609 Some(format!("{}{};", prefix, type_bounds_str))
1613 pub fn rewrite_associated_impl_type(
1615 defaultness: ast::Defaultness,
1616 ty_opt: Option<&ptr::P<ast::Ty>>,
1617 ty_param_bounds_opt: Option<&ast::TyParamBounds>,
1618 context: &RewriteContext,
1620 ) -> Option<String> {
1621 let result = rewrite_associated_type(ident, ty_opt, ty_param_bounds_opt, context, indent)?;
1624 ast::Defaultness::Default => Some(format!("default {}", result)),
1629 impl Rewrite for ast::FunctionRetTy {
1630 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
1632 ast::FunctionRetTy::Default(_) => Some(String::new()),
1633 ast::FunctionRetTy::Ty(ref ty) => {
1634 let inner_width = shape.width.checked_sub(3)?;
1635 ty.rewrite(context, Shape::legacy(inner_width, shape.indent + 3))
1636 .map(|r| format!("-> {}", r))
1642 fn is_empty_infer(context: &RewriteContext, ty: &ast::Ty) -> bool {
1644 ast::TyKind::Infer => {
1645 let original = context.snippet(ty.span);
1652 impl Rewrite for ast::Arg {
1653 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
1654 if is_named_arg(self) {
1655 let mut result = self.pat
1656 .rewrite(context, Shape::legacy(shape.width, shape.indent))?;
1658 if !is_empty_infer(context, &*self.ty) {
1659 if context.config.space_before_colon() {
1660 result.push_str(" ");
1662 result.push_str(":");
1663 if context.config.space_after_colon() {
1664 result.push_str(" ");
1666 let overhead = last_line_width(&result);
1667 let max_width = shape.width.checked_sub(overhead)?;
1668 let ty_str = self.ty
1669 .rewrite(context, Shape::legacy(max_width, shape.indent))?;
1670 result.push_str(&ty_str);
1675 self.ty.rewrite(context, shape)
1680 fn rewrite_explicit_self(
1681 explicit_self: &ast::ExplicitSelf,
1683 context: &RewriteContext,
1684 ) -> Option<String> {
1685 match explicit_self.node {
1686 ast::SelfKind::Region(lt, m) => {
1687 let mut_str = format_mutability(m);
1690 let lifetime_str = l.rewrite(
1692 Shape::legacy(context.config.max_width(), Indent::empty()),
1694 Some(format!("&{} {}self", lifetime_str, mut_str))
1696 None => Some(format!("&{}self", mut_str)),
1699 ast::SelfKind::Explicit(ref ty, _) => {
1700 assert!(!args.is_empty(), "&[ast::Arg] shouldn't be empty.");
1702 let mutability = explicit_self_mutability(&args[0]);
1703 let type_str = ty.rewrite(
1705 Shape::legacy(context.config.max_width(), Indent::empty()),
1710 format_mutability(mutability),
1714 ast::SelfKind::Value(_) => {
1715 assert!(!args.is_empty(), "&[ast::Arg] shouldn't be empty.");
1717 let mutability = explicit_self_mutability(&args[0]);
1719 Some(format!("{}self", format_mutability(mutability)))
1724 // Hacky solution caused by absence of `Mutability` in `SelfValue` and
1725 // `SelfExplicit` variants of `ast::ExplicitSelf_`.
1726 fn explicit_self_mutability(arg: &ast::Arg) -> ast::Mutability {
1727 if let ast::PatKind::Ident(ast::BindingMode::ByValue(mutability), _, _) = arg.pat.node {
1734 pub fn span_lo_for_arg(arg: &ast::Arg) -> BytePos {
1735 if is_named_arg(arg) {
1742 pub fn span_hi_for_arg(context: &RewriteContext, arg: &ast::Arg) -> BytePos {
1744 ast::TyKind::Infer if context.snippet(arg.ty.span) == "_" => arg.ty.span.hi(),
1745 ast::TyKind::Infer if is_named_arg(arg) => arg.pat.span.hi(),
1746 _ => arg.ty.span.hi(),
1750 pub fn is_named_arg(arg: &ast::Arg) -> bool {
1751 if let ast::PatKind::Ident(_, ident, _) = arg.pat.node {
1752 ident.node != symbol::keywords::Invalid.ident()
1758 // Return type is (result, force_new_line_for_brace)
1760 context: &RewriteContext,
1765 newline_brace: bool,
1767 ) -> Option<(String, bool)> {
1768 let mut force_new_line_for_brace = false;
1770 let where_clause = &fn_sig.generics.where_clause;
1772 let mut result = String::with_capacity(1024);
1773 result.push_str(&fn_sig.to_str(context));
1776 result.push_str("fn ");
1779 let overhead = if has_body && !newline_brace {
1786 let used_width = last_line_used_width(&result, indent.width());
1787 let one_line_budget = context.budget(used_width + overhead);
1789 width: one_line_budget,
1793 let fd = fn_sig.decl;
1794 let g_span = mk_sp(span.lo(), fd.output.span().lo());
1796 rewrite_generics(context, &ident.to_string(), fn_sig.generics, shape, g_span)?;
1797 result.push_str(&generics_str);
1799 let snuggle_angle_bracket = generics_str
1802 .map_or(false, |l| l.trim_left().len() == 1);
1804 // Note that the width and indent don't really matter, we'll re-layout the
1805 // return type later anyway.
1806 let ret_str = fd.output
1807 .rewrite(context, Shape::indented(indent, context.config))?;
1809 let multi_line_ret_str = ret_str.contains('\n');
1810 let ret_str_len = if multi_line_ret_str { 0 } else { ret_str.len() };
1813 let (one_line_budget, multi_line_budget, mut arg_indent) = compute_budgets_for_args(
1824 "rewrite_fn_base: one_line_budget: {}, multi_line_budget: {}, arg_indent: {:?}",
1825 one_line_budget, multi_line_budget, arg_indent
1828 // Check if vertical layout was forced.
1829 if one_line_budget == 0 {
1830 if snuggle_angle_bracket {
1833 result.push_str("(");
1834 if context.config.indent_style() == IndentStyle::Visual {
1835 result.push_str(&arg_indent.to_string_with_newline(context.config));
1841 if context.config.spaces_within_parens_and_brackets() && !fd.inputs.is_empty()
1842 && result.ends_with('(')
1847 // Skip `pub(crate)`.
1848 let lo_after_visibility = get_bytepos_after_visibility(&fn_sig.visibility, span);
1849 // A conservative estimation, to goal is to be over all parens in generics
1850 let args_start = fn_sig
1855 .map_or(lo_after_visibility, |param| param.span().hi());
1856 let args_end = if fd.inputs.is_empty() {
1859 .span_after(mk_sp(args_start, span.hi()), ")")
1861 let last_span = mk_sp(fd.inputs[fd.inputs.len() - 1].span().hi(), span.hi());
1862 context.snippet_provider.span_after(last_span, ")")
1864 let args_span = mk_sp(
1867 .span_after(mk_sp(args_start, span.hi()), "("),
1870 let arg_str = rewrite_args(
1873 fd.get_self().as_ref(),
1880 generics_str.contains('\n'),
1883 let put_args_in_block = match context.config.indent_style() {
1884 IndentStyle::Block => arg_str.contains('\n') || arg_str.len() > one_line_budget,
1886 } && !fd.inputs.is_empty();
1888 let mut args_last_line_contains_comment = false;
1889 if put_args_in_block {
1890 arg_indent = indent.block_indent(context.config);
1891 result.push_str(&arg_indent.to_string_with_newline(context.config));
1892 result.push_str(&arg_str);
1893 result.push_str(&indent.to_string_with_newline(context.config));
1896 result.push_str(&arg_str);
1897 let used_width = last_line_used_width(&result, indent.width()) + first_line_width(&ret_str);
1898 // Put the closing brace on the next line if it overflows the max width.
1900 if fd.inputs.is_empty() && used_width + 1 > context.config.max_width() {
1903 if context.config.spaces_within_parens_and_brackets() && !fd.inputs.is_empty() {
1906 // If the last line of args contains comment, we cannot put the closing paren
1907 // on the same line.
1911 .map_or(false, |last_line| last_line.contains("//"))
1913 args_last_line_contains_comment = true;
1914 result.push_str(&arg_indent.to_string_with_newline(context.config));
1920 if let ast::FunctionRetTy::Ty(..) = fd.output {
1921 let ret_should_indent = match context.config.indent_style() {
1922 // If our args are block layout then we surely must have space.
1923 IndentStyle::Block if put_args_in_block || fd.inputs.is_empty() => false,
1924 _ if args_last_line_contains_comment => false,
1925 _ if result.contains('\n') || multi_line_ret_str => true,
1927 // If the return type would push over the max width, then put the return type on
1928 // a new line. With the +1 for the signature length an additional space between
1929 // the closing parenthesis of the argument and the arrow '->' is considered.
1930 let mut sig_length = result.len() + indent.width() + ret_str_len + 1;
1932 // If there is no where clause, take into account the space after the return type
1934 if where_clause.predicates.is_empty() {
1938 sig_length > context.config.max_width()
1941 let ret_indent = if ret_should_indent {
1942 let indent = if arg_str.is_empty() {
1943 // Aligning with non-existent args looks silly.
1944 force_new_line_for_brace = true;
1947 // FIXME: we might want to check that using the arg indent
1948 // doesn't blow our budget, and if it does, then fallback to
1949 // the where clause indent.
1953 result.push_str(&indent.to_string_with_newline(context.config));
1957 Indent::new(indent.block_indent, last_line_width(&result))
1960 if multi_line_ret_str || ret_should_indent {
1961 // Now that we know the proper indent and width, we need to
1962 // re-layout the return type.
1963 let ret_str = fd.output
1964 .rewrite(context, Shape::indented(ret_indent, context.config))?;
1965 result.push_str(&ret_str);
1967 result.push_str(&ret_str);
1970 // Comment between return type and the end of the decl.
1971 let snippet_lo = fd.output.span().hi();
1972 if where_clause.predicates.is_empty() {
1973 let snippet_hi = span.hi();
1974 let snippet = context.snippet(mk_sp(snippet_lo, snippet_hi));
1975 // Try to preserve the layout of the original snippet.
1976 let original_starts_with_newline = snippet
1978 .map_or(false, |i| starts_with_newline(&snippet[i..]));
1979 let original_ends_with_newline = snippet
1980 .rfind(|c| c != ' ')
1981 .map_or(false, |i| snippet[i..].ends_with('\n'));
1982 let snippet = snippet.trim();
1983 if !snippet.is_empty() {
1984 result.push(if original_starts_with_newline {
1989 result.push_str(snippet);
1990 if original_ends_with_newline {
1991 force_new_line_for_brace = true;
1997 let pos_before_where = match fd.output {
1998 ast::FunctionRetTy::Default(..) => args_span.hi(),
1999 ast::FunctionRetTy::Ty(ref ty) => ty.span.hi(),
2002 let is_args_multi_lined = arg_str.contains('\n');
2004 let option = WhereClauseOption::new(!has_body, put_args_in_block && ret_str.is_empty());
2005 let where_clause_str = rewrite_where_clause(
2008 context.config.brace_style(),
2009 Shape::indented(indent, context.config),
2015 is_args_multi_lined,
2017 // If there are neither where clause nor return type, we may be missing comments between
2019 if where_clause_str.is_empty() {
2020 if let ast::FunctionRetTy::Default(ret_span) = fd.output {
2021 match recover_missing_comment_in_span(
2022 mk_sp(args_span.hi(), ret_span.hi()),
2025 last_line_width(&result),
2027 Some(ref missing_comment) if !missing_comment.is_empty() => {
2028 result.push_str(missing_comment);
2029 force_new_line_for_brace = true;
2036 result.push_str(&where_clause_str);
2038 force_new_line_for_brace |= last_line_contains_single_line_comment(&result);
2039 force_new_line_for_brace |= is_args_multi_lined && context.config.where_single_line();
2040 Some((result, force_new_line_for_brace))
2043 #[derive(Copy, Clone)]
2044 struct WhereClauseOption {
2045 suppress_comma: bool, // Force no trailing comma
2046 snuggle: bool, // Do not insert newline before `where`
2047 compress_where: bool, // Try single line where clause instead of vertical layout
2050 impl WhereClauseOption {
2051 pub fn new(suppress_comma: bool, snuggle: bool) -> WhereClauseOption {
2055 compress_where: false,
2059 pub fn snuggled(current: &str) -> WhereClauseOption {
2061 suppress_comma: false,
2062 snuggle: trimmed_last_line_width(current) == 1,
2063 compress_where: false,
2069 context: &RewriteContext,
2071 explicit_self: Option<&ast::ExplicitSelf>,
2072 one_line_budget: usize,
2073 multi_line_budget: usize,
2078 generics_str_contains_newline: bool,
2079 ) -> Option<String> {
2080 let mut arg_item_strs = args.iter()
2081 .map(|arg| arg.rewrite(context, Shape::legacy(multi_line_budget, arg_indent)))
2082 .collect::<Option<Vec<_>>>()?;
2084 // Account for sugary self.
2085 // FIXME: the comment for the self argument is dropped. This is blocked
2086 // on rust issue #27522.
2087 let min_args = explicit_self
2088 .and_then(|explicit_self| rewrite_explicit_self(explicit_self, args, context))
2089 .map_or(1, |self_str| {
2090 arg_item_strs[0] = self_str;
2094 // Comments between args.
2095 let mut arg_items = Vec::new();
2097 arg_items.push(ListItem::from_str(""));
2100 // FIXME(#21): if there are no args, there might still be a comment, but
2101 // without spans for the comment or parens, there is no chance of
2102 // getting it right. You also don't get to put a comment on self, unless
2104 if args.len() >= min_args || variadic {
2105 let comment_span_start = if min_args == 2 {
2106 let second_arg_start = if arg_has_pattern(&args[1]) {
2107 args[1].pat.span.lo()
2109 args[1].ty.span.lo()
2111 let reduced_span = mk_sp(span.lo(), second_arg_start);
2113 context.snippet_provider.span_after_last(reduced_span, ",")
2118 enum ArgumentKind<'a> {
2119 Regular(&'a ast::Arg),
2123 let variadic_arg = if variadic {
2124 let variadic_span = mk_sp(args.last().unwrap().ty.span.hi(), span.hi());
2125 let variadic_start =
2126 context.snippet_provider.span_after(variadic_span, "...") - BytePos(3);
2127 Some(ArgumentKind::Variadic(variadic_start))
2132 let more_items = itemize_list(
2133 context.snippet_provider,
2134 args[min_args - 1..]
2136 .map(ArgumentKind::Regular)
2137 .chain(variadic_arg),
2141 ArgumentKind::Regular(arg) => span_lo_for_arg(arg),
2142 ArgumentKind::Variadic(start) => start,
2145 ArgumentKind::Regular(arg) => arg.ty.span.hi(),
2146 ArgumentKind::Variadic(start) => start + BytePos(3),
2149 ArgumentKind::Regular(..) => None,
2150 ArgumentKind::Variadic(..) => Some("...".to_owned()),
2157 arg_items.extend(more_items);
2160 let fits_in_one_line = !generics_str_contains_newline
2161 && (arg_items.is_empty()
2162 || arg_items.len() == 1 && arg_item_strs[0].len() <= one_line_budget);
2164 for (item, arg) in arg_items.iter_mut().zip(arg_item_strs) {
2165 item.item = Some(arg);
2168 let last_line_ends_with_comment = arg_items
2171 .and_then(|item| item.post_comment.as_ref())
2172 .map_or(false, |s| s.trim().starts_with("//"));
2174 let (indent, trailing_comma) = match context.config.indent_style() {
2175 IndentStyle::Block if fits_in_one_line => {
2176 (indent.block_indent(context.config), SeparatorTactic::Never)
2178 IndentStyle::Block => (
2179 indent.block_indent(context.config),
2180 context.config.trailing_comma(),
2182 IndentStyle::Visual if last_line_ends_with_comment => {
2183 (arg_indent, context.config.trailing_comma())
2185 IndentStyle::Visual => (arg_indent, SeparatorTactic::Never),
2188 let tactic = definitive_tactic(
2190 context.config.fn_args_density().to_list_tactic(),
2194 let budget = match tactic {
2195 DefinitiveListTactic::Horizontal => one_line_budget,
2196 _ => multi_line_budget,
2199 debug!("rewrite_args: budget: {}, tactic: {:?}", budget, tactic);
2201 let fmt = ListFormatting {
2204 trailing_separator: if variadic {
2205 SeparatorTactic::Never
2209 separator_place: SeparatorPlace::Back,
2210 shape: Shape::legacy(budget, indent),
2211 ends_with_newline: tactic.ends_with_newline(context.config.indent_style()),
2212 preserve_newline: true,
2213 config: context.config,
2216 write_list(&arg_items, &fmt)
2219 fn arg_has_pattern(arg: &ast::Arg) -> bool {
2220 if let ast::PatKind::Ident(_, ident, _) = arg.pat.node {
2221 ident.node != symbol::keywords::Invalid.ident()
2227 fn compute_budgets_for_args(
2228 context: &RewriteContext,
2232 newline_brace: bool,
2234 force_vertical_layout: bool,
2235 ) -> Option<((usize, usize, Indent))> {
2237 "compute_budgets_for_args {} {:?}, {}, {}",
2243 // Try keeping everything on the same line.
2244 if !result.contains('\n') && !force_vertical_layout {
2245 // 2 = `()`, 3 = `() `, space is before ret_string.
2246 let overhead = if ret_str_len == 0 { 2 } else { 3 };
2247 let mut used_space = indent.width() + result.len() + ret_str_len + overhead;
2257 let one_line_budget = context.budget(used_space);
2259 if one_line_budget > 0 {
2261 let (indent, multi_line_budget) = match context.config.indent_style() {
2262 IndentStyle::Block => {
2263 let indent = indent.block_indent(context.config);
2264 (indent, context.budget(indent.width() + 1))
2266 IndentStyle::Visual => {
2267 let indent = indent + result.len() + 1;
2268 let multi_line_overhead = indent.width() + if newline_brace { 2 } else { 4 };
2269 (indent, context.budget(multi_line_overhead))
2273 return Some((one_line_budget, multi_line_budget, indent));
2277 // Didn't work. we must force vertical layout and put args on a newline.
2278 let new_indent = indent.block_indent(context.config);
2279 let used_space = match context.config.indent_style() {
2281 IndentStyle::Block => new_indent.width() + 1,
2282 // Account for `)` and possibly ` {`.
2283 IndentStyle::Visual => new_indent.width() + if ret_str_len == 0 { 1 } else { 3 },
2285 Some((0, context.budget(used_space), new_indent))
2288 fn newline_for_brace(config: &Config, where_clause: &ast::WhereClause) -> bool {
2289 let predicate_count = where_clause.predicates.len();
2291 if config.where_single_line() && predicate_count == 1 {
2294 let brace_style = config.brace_style();
2296 brace_style == BraceStyle::AlwaysNextLine
2297 || (brace_style == BraceStyle::SameLineWhere && predicate_count > 0)
2300 fn rewrite_generics(
2301 context: &RewriteContext,
2303 generics: &ast::Generics,
2306 ) -> Option<String> {
2307 // FIXME: convert bounds to where clauses where they get too big or if
2308 // there is a where clause at all.
2310 if generics.params.is_empty() {
2311 return Some(ident.to_owned());
2314 let params = &generics.params.iter().map(|e| &*e).collect::<Vec<_>>()[..];
2315 overflow::rewrite_with_angle_brackets(context, ident, params, shape, span)
2318 pub fn generics_shape_from_config(config: &Config, shape: Shape, offset: usize) -> Option<Shape> {
2319 match config.indent_style() {
2320 IndentStyle::Visual => shape.visual_indent(1 + offset).sub_width(offset + 2),
2321 IndentStyle::Block => {
2325 .block_indent(config.tab_spaces())
2326 .with_max_width(config)
2332 fn rewrite_trait_bounds(
2333 context: &RewriteContext,
2334 bounds: &[ast::TyParamBound],
2336 ) -> Option<String> {
2337 if bounds.is_empty() {
2338 return Some(String::new());
2340 let bound_str = bounds
2342 .map(|ty_bound| ty_bound.rewrite(context, shape))
2343 .collect::<Option<Vec<_>>>()?;
2344 Some(format!(": {}", join_bounds(context, shape, &bound_str)))
2347 fn rewrite_where_clause_rfc_style(
2348 context: &RewriteContext,
2349 where_clause: &ast::WhereClause,
2352 span_end: Option<BytePos>,
2353 span_end_before_where: BytePos,
2354 where_clause_option: WhereClauseOption,
2355 is_args_multi_line: bool,
2356 ) -> Option<String> {
2357 let block_shape = shape.block().with_max_width(context.config);
2359 let (span_before, span_after) =
2360 missing_span_before_after_where(span_end_before_where, where_clause);
2361 let (comment_before, comment_after) =
2362 rewrite_comments_before_after_where(context, span_before, span_after, shape)?;
2364 let starting_newline = if where_clause_option.snuggle && comment_before.is_empty() {
2367 block_shape.indent.to_string_with_newline(context.config)
2370 let clause_shape = block_shape.block_left(context.config.tab_spaces())?;
2372 let clause_shape = clause_shape.sub_width(1)?;
2373 // each clause on one line, trailing comma (except if suppress_comma)
2374 let span_start = where_clause.predicates[0].span().lo();
2375 // If we don't have the start of the next span, then use the end of the
2376 // predicates, but that means we miss comments.
2377 let len = where_clause.predicates.len();
2378 let end_of_preds = where_clause.predicates[len - 1].span().hi();
2379 let span_end = span_end.unwrap_or(end_of_preds);
2380 let items = itemize_list(
2381 context.snippet_provider,
2382 where_clause.predicates.iter(),
2385 |pred| pred.span().lo(),
2386 |pred| pred.span().hi(),
2387 |pred| pred.rewrite(context, clause_shape),
2392 let where_single_line = context.config.where_single_line() && len == 1 && !is_args_multi_line;
2393 let comma_tactic = if where_clause_option.suppress_comma || where_single_line {
2394 SeparatorTactic::Never
2396 context.config.trailing_comma()
2399 // shape should be vertical only and only if we have `where_single_line` option enabled
2400 // and the number of items of the where clause is equal to 1
2401 let shape_tactic = if where_single_line {
2402 DefinitiveListTactic::Horizontal
2404 DefinitiveListTactic::Vertical
2407 let fmt = ListFormatting {
2408 tactic: shape_tactic,
2410 trailing_separator: comma_tactic,
2411 separator_place: SeparatorPlace::Back,
2412 shape: clause_shape,
2413 ends_with_newline: true,
2414 preserve_newline: true,
2415 config: context.config,
2417 let preds_str = write_list(&items.collect::<Vec<_>>(), &fmt)?;
2419 let comment_separator = |comment: &str, shape: Shape| {
2420 if comment.is_empty() {
2423 shape.indent.to_string_with_newline(context.config)
2426 let newline_before_where = comment_separator(&comment_before, shape);
2427 let newline_after_where = comment_separator(&comment_after, clause_shape);
2430 let clause_sep = if where_clause_option.compress_where && comment_before.is_empty()
2431 && comment_after.is_empty() && !preds_str.contains('\n')
2432 && 6 + preds_str.len() <= shape.width || where_single_line
2436 clause_shape.indent.to_string_with_newline(context.config)
2439 "{}{}{}where{}{}{}{}",
2442 newline_before_where,
2443 newline_after_where,
2450 fn rewrite_where_clause(
2451 context: &RewriteContext,
2452 where_clause: &ast::WhereClause,
2453 brace_style: BraceStyle,
2457 span_end: Option<BytePos>,
2458 span_end_before_where: BytePos,
2459 where_clause_option: WhereClauseOption,
2460 is_args_multi_line: bool,
2461 ) -> Option<String> {
2462 if where_clause.predicates.is_empty() {
2463 return Some(String::new());
2466 if context.config.indent_style() == IndentStyle::Block {
2467 return rewrite_where_clause_rfc_style(
2473 span_end_before_where,
2474 where_clause_option,
2479 let extra_indent = Indent::new(context.config.tab_spaces(), 0);
2481 let offset = match context.config.indent_style() {
2482 IndentStyle::Block => shape.indent + extra_indent.block_indent(context.config),
2483 // 6 = "where ".len()
2484 IndentStyle::Visual => shape.indent + extra_indent + 6,
2486 // FIXME: if indent_style != Visual, then the budgets below might
2487 // be out by a char or two.
2489 let budget = context.config.max_width() - offset.width();
2490 let span_start = where_clause.predicates[0].span().lo();
2491 // If we don't have the start of the next span, then use the end of the
2492 // predicates, but that means we miss comments.
2493 let len = where_clause.predicates.len();
2494 let end_of_preds = where_clause.predicates[len - 1].span().hi();
2495 let span_end = span_end.unwrap_or(end_of_preds);
2496 let items = itemize_list(
2497 context.snippet_provider,
2498 where_clause.predicates.iter(),
2501 |pred| pred.span().lo(),
2502 |pred| pred.span().hi(),
2503 |pred| pred.rewrite(context, Shape::legacy(budget, offset)),
2508 let item_vec = items.collect::<Vec<_>>();
2509 // FIXME: we don't need to collect here
2510 let tactic = definitive_tactic(&item_vec, ListTactic::Vertical, Separator::Comma, budget);
2512 let mut comma_tactic = context.config.trailing_comma();
2513 // Kind of a hack because we don't usually have trailing commas in where clauses.
2514 if comma_tactic == SeparatorTactic::Vertical || where_clause_option.suppress_comma {
2515 comma_tactic = SeparatorTactic::Never;
2518 let fmt = ListFormatting {
2521 trailing_separator: comma_tactic,
2522 separator_place: SeparatorPlace::Back,
2523 shape: Shape::legacy(budget, offset),
2524 ends_with_newline: tactic.ends_with_newline(context.config.indent_style()),
2525 preserve_newline: true,
2526 config: context.config,
2528 let preds_str = write_list(&item_vec, &fmt)?;
2530 let end_length = if terminator == "{" {
2531 // If the brace is on the next line we don't need to count it otherwise it needs two
2534 BraceStyle::AlwaysNextLine | BraceStyle::SameLineWhere => 0,
2535 BraceStyle::PreferSameLine => 2,
2537 } else if terminator == "=" {
2542 if density == Density::Tall || preds_str.contains('\n')
2543 || shape.indent.width() + " where ".len() + preds_str.len() + end_length > shape.width
2547 (shape.indent + extra_indent).to_string(context.config),
2551 Some(format!(" where {}", preds_str))
2555 fn missing_span_before_after_where(
2556 before_item_span_end: BytePos,
2557 where_clause: &ast::WhereClause,
2559 let missing_span_before = mk_sp(before_item_span_end, where_clause.span.lo());
2561 let pos_after_where = where_clause.span.lo() + BytePos(5);
2562 let missing_span_after = mk_sp(pos_after_where, where_clause.predicates[0].span().lo());
2563 (missing_span_before, missing_span_after)
2566 fn rewrite_comments_before_after_where(
2567 context: &RewriteContext,
2568 span_before_where: Span,
2569 span_after_where: Span,
2571 ) -> Option<(String, String)> {
2572 let before_comment = rewrite_missing_comment(span_before_where, shape, context)?;
2573 let after_comment = rewrite_missing_comment(
2575 shape.block_indent(context.config.tab_spaces()),
2578 Some((before_comment, after_comment))
2581 fn format_header(item_name: &str, ident: ast::Ident, vis: &ast::Visibility) -> String {
2582 format!("{}{}{}", format_visibility(vis), item_name, ident)
2585 #[derive(PartialEq, Eq, Clone, Copy)]
2593 context: &RewriteContext,
2594 generics: &ast::Generics,
2595 brace_style: BraceStyle,
2596 brace_pos: BracePos,
2600 ) -> Option<String> {
2601 let shape = Shape::legacy(context.budget(used_width + offset.width()), offset);
2602 let mut result = rewrite_generics(context, "", generics, shape, span)?;
2604 let same_line_brace = if !generics.where_clause.predicates.is_empty() || result.contains('\n') {
2605 let budget = context.budget(last_line_used_width(&result, offset.width()));
2606 let mut option = WhereClauseOption::snuggled(&result);
2607 if brace_pos == BracePos::None {
2608 option.suppress_comma = true;
2610 // If the generics are not parameterized then generics.span.hi() == 0,
2611 // so we use span.lo(), which is the position after `struct Foo`.
2612 let span_end_before_where = if generics.is_parameterized() {
2617 let where_clause_str = rewrite_where_clause(
2619 &generics.where_clause,
2621 Shape::legacy(budget, offset.block_only()),
2625 span_end_before_where,
2629 result.push_str(&where_clause_str);
2630 brace_pos == BracePos::ForceSameLine || brace_style == BraceStyle::PreferSameLine
2631 || (generics.where_clause.predicates.is_empty()
2632 && trimmed_last_line_width(&result) == 1)
2634 brace_pos == BracePos::ForceSameLine || trimmed_last_line_width(&result) == 1
2635 || brace_style != BraceStyle::AlwaysNextLine
2637 if brace_pos == BracePos::None {
2638 return Some(result);
2640 let total_used_width = last_line_used_width(&result, used_width);
2641 let remaining_budget = context.budget(total_used_width);
2642 // If the same line brace if forced, it indicates that we are rewriting an item with empty body,
2643 // and hence we take the closer into account as well for one line budget.
2644 // We assume that the closer has the same length as the opener.
2645 let overhead = if brace_pos == BracePos::ForceSameLine {
2652 let forbid_same_line_brace = overhead > remaining_budget;
2653 if !forbid_same_line_brace && same_line_brace {
2657 result.push_str(&offset.block_only().to_string(context.config));
2664 impl Rewrite for ast::ForeignItem {
2665 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
2666 let attrs_str = self.attrs.rewrite(context, shape)?;
2667 // Drop semicolon or it will be interpreted as comment.
2668 // FIXME: this may be a faulty span from libsyntax.
2669 let span = mk_sp(self.span.lo(), self.span.hi() - BytePos(1));
2671 let item_str = match self.node {
2672 ast::ForeignItemKind::Fn(ref fn_decl, ref generics) => {
2677 &FnSig::new(fn_decl, generics, self.vis.clone()),
2681 ).map(|(s, _)| format!("{};", s))
2683 ast::ForeignItemKind::Static(ref ty, is_mutable) => {
2684 // FIXME(#21): we're dropping potential comments in between the
2685 // function keywords here.
2686 let vis = format_visibility(&self.vis);
2687 let mut_str = if is_mutable { "mut " } else { "" };
2688 let prefix = format!("{}static {}{}:", vis, mut_str, self.ident);
2690 let shape = shape.sub_width(1)?;
2691 ty.rewrite(context, shape).map(|ty_str| {
2692 // 1 = space between prefix and type.
2693 let sep = if prefix.len() + ty_str.len() + 1 <= shape.width {
2696 let nested_indent = shape.indent.block_indent(context.config);
2697 nested_indent.to_string_with_newline(context.config)
2699 format!("{}{}{};", prefix, sep, ty_str)
2702 ast::ForeignItemKind::Ty => {
2703 let vis = format_visibility(&self.vis);
2704 Some(format!("{}type {};", vis, self.ident))
2708 let missing_span = if self.attrs.is_empty() {
2709 mk_sp(self.span.lo(), self.span.lo())
2711 mk_sp(self.attrs[self.attrs.len() - 1].span.hi(), self.span.lo())
2713 combine_strs_with_missing_comments(
2724 impl Rewrite for ast::GenericParam {
2725 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
2727 ast::GenericParam::Lifetime(ref lifetime_def) => lifetime_def.rewrite(context, shape),
2728 ast::GenericParam::Type(ref ty) => ty.rewrite(context, shape),
2733 /// Rewrite an inline mod.
2734 pub fn rewrite_mod(item: &ast::Item) -> String {
2735 let mut result = String::with_capacity(32);
2736 result.push_str(&*format_visibility(&item.vis));
2737 result.push_str("mod ");
2738 result.push_str(&item.ident.to_string());
2743 /// Rewrite `extern crate foo;` WITHOUT attributes.
2744 pub fn rewrite_extern_crate(context: &RewriteContext, item: &ast::Item) -> Option<String> {
2745 assert!(is_extern_crate(item));
2746 let new_str = context.snippet(item.span);
2747 Some(if contains_comment(new_str) {
2750 let no_whitespace = &new_str.split_whitespace().collect::<Vec<&str>>().join(" ");
2751 String::from(&*Regex::new(r"\s;").unwrap().replace(no_whitespace, ";"))
2755 /// Returns true for `mod foo;`, false for `mod foo { .. }`.
2756 pub fn is_mod_decl(item: &ast::Item) -> bool {
2758 ast::ItemKind::Mod(ref m) => m.inner.hi() != item.span.hi(),
2763 pub fn is_use_item(item: &ast::Item) -> bool {
2765 ast::ItemKind::Use(_) => true,
2770 pub fn is_extern_crate(item: &ast::Item) -> bool {
2772 ast::ItemKind::ExternCrate(..) => true,