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.
14 use std::cmp::{min, Ordering};
18 use rustc_target::spec::abi;
19 use syntax::codemap::{self, BytePos, Span};
21 use syntax::{ast, ptr, symbol};
23 use codemap::{LineRangeUtils, SpanUtils};
25 combine_strs_with_missing_comments, contains_comment, recover_comment_removed,
26 recover_missing_comment_in_span, rewrite_missing_comment, FindUncommented,
28 use config::{BraceStyle, Config, Density, IndentStyle};
30 format_expr, is_empty_block, is_simple_block_stmt, rewrite_assign_rhs, rewrite_assign_rhs_with,
33 use lists::{definitive_tactic, itemize_list, write_list, ListFormatting, ListItem, Separator};
34 use macros::{rewrite_macro, MacroPosition};
36 use rewrite::{Rewrite, RewriteContext};
37 use shape::{Indent, Shape};
39 use types::TraitTyParamBounds;
41 use vertical::rewrite_with_alignment;
42 use visitor::FmtVisitor;
44 const DEFAULT_VISIBILITY: ast::Visibility = codemap::Spanned {
45 node: ast::VisibilityKind::Inherited,
46 span: codemap::DUMMY_SP,
49 fn type_annotation_separator(config: &Config) -> &str {
50 colon_spaces(config.space_before_colon(), config.space_after_colon())
53 // Statements of the form
54 // let pat: ty = init;
55 impl Rewrite for ast::Local {
56 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
58 "Local::rewrite {:?} {} {:?}",
59 self, shape.width, shape.indent
62 skip_out_of_file_lines_range!(context, self.span);
64 if contains_skip(&self.attrs) {
68 let attrs_str = self.attrs.rewrite(context, shape)?;
69 let mut result = if attrs_str.is_empty() {
72 combine_strs_with_missing_comments(
77 self.attrs.last().map(|a| a.span.hi()).unwrap(),
86 let pat_shape = shape.offset_left(4)?;
88 let pat_shape = pat_shape.sub_width(1)?;
89 let pat_str = self.pat.rewrite(context, pat_shape)?;
90 result.push_str(&pat_str);
92 // String that is placed within the assignment pattern and expression.
94 let mut infix = String::with_capacity(32);
96 if let Some(ref ty) = self.ty {
97 let separator = type_annotation_separator(context.config);
98 let indent = shape.indent + last_line_width(&result) + separator.len();
100 let budget = shape.width.checked_sub(indent.width() + 1)?;
101 let rewrite = ty.rewrite(context, Shape::legacy(budget, indent))?;
103 infix.push_str(separator);
104 infix.push_str(&rewrite);
107 if self.init.is_some() {
108 infix.push_str(" =");
114 result.push_str(&infix);
116 if let Some(ref ex) = self.init {
117 // 1 = trailing semicolon;
118 let nested_shape = shape.sub_width(1)?;
120 result = rewrite_assign_rhs(context, result, &**ex, nested_shape)?;
128 // TODO convert to using rewrite style rather than visitor
129 // TODO format modules in this style
132 keyword: &'static str,
133 abi: Cow<'static, str>,
134 vis: Option<&'a ast::Visibility>,
135 body: Vec<BodyElement<'a>>,
140 fn from_foreign_mod(fm: &'a ast::ForeignMod, span: Span, config: &Config) -> Item<'a> {
143 abi: format_abi(fm.abi, config.force_explicit_abi(), true),
147 .map(|i| BodyElement::ForeignItem(i))
154 enum BodyElement<'a> {
155 // Stmt(&'a ast::Stmt),
156 // Field(&'a ast::Field),
157 // Variant(&'a ast::Variant),
158 // Item(&'a ast::Item),
159 ForeignItem(&'a ast::ForeignItem),
162 /// Represents a fn's signature.
163 pub struct FnSig<'a> {
164 decl: &'a ast::FnDecl,
165 generics: &'a ast::Generics,
167 constness: ast::Constness,
168 defaultness: ast::Defaultness,
169 unsafety: ast::Unsafety,
170 visibility: ast::Visibility,
175 decl: &'a ast::FnDecl,
176 generics: &'a ast::Generics,
177 vis: ast::Visibility,
183 constness: ast::Constness::NotConst,
184 defaultness: ast::Defaultness::Final,
185 unsafety: ast::Unsafety::Normal,
190 pub fn from_method_sig(
191 method_sig: &'a ast::MethodSig,
192 generics: &'a ast::Generics,
195 unsafety: method_sig.unsafety,
196 constness: method_sig.constness.node,
197 defaultness: ast::Defaultness::Final,
199 decl: &*method_sig.decl,
201 visibility: DEFAULT_VISIBILITY,
206 fn_kind: &'a visit::FnKind,
207 generics: &'a ast::Generics,
208 decl: &'a ast::FnDecl,
209 defaultness: ast::Defaultness,
212 visit::FnKind::ItemFn(_, unsafety, constness, abi, visibility, _) => FnSig {
216 constness: constness.node,
219 visibility: visibility.clone(),
221 visit::FnKind::Method(_, method_sig, vis, _) => {
222 let mut fn_sig = FnSig::from_method_sig(method_sig, generics);
223 fn_sig.defaultness = defaultness;
224 if let Some(vis) = vis {
225 fn_sig.visibility = vis.clone();
233 fn to_str(&self, context: &RewriteContext) -> String {
234 let mut result = String::with_capacity(128);
235 // Vis defaultness constness unsafety abi.
236 result.push_str(&*format_visibility(&self.visibility));
237 result.push_str(format_defaultness(self.defaultness));
238 result.push_str(format_constness(self.constness));
239 result.push_str(format_unsafety(self.unsafety));
240 result.push_str(&format_abi(
242 context.config.force_explicit_abi(),
249 impl<'a> FmtVisitor<'a> {
250 fn format_item(&mut self, item: &Item) {
251 self.buffer.push_str(&item.abi);
253 let snippet = self.snippet(item.span);
254 let brace_pos = snippet.find_uncommented("{").unwrap();
257 if !item.body.is_empty() || contains_comment(&snippet[brace_pos..]) {
258 // FIXME: this skips comments between the extern keyword and the opening
260 self.last_pos = item.span.lo() + BytePos(brace_pos as u32 + 1);
261 self.block_indent = self.block_indent.block_indent(self.config);
263 if item.body.is_empty() {
264 self.format_missing_no_indent(item.span.hi() - BytePos(1));
265 self.block_indent = self.block_indent.block_unindent(self.config);
266 let indent_str = self.block_indent.to_string(self.config);
267 self.push_str(&indent_str);
269 for item in &item.body {
270 self.format_body_element(item);
273 self.block_indent = self.block_indent.block_unindent(self.config);
274 self.format_missing_with_indent(item.span.hi() - BytePos(1));
279 self.last_pos = item.span.hi();
282 fn format_body_element(&mut self, element: &BodyElement) {
284 BodyElement::ForeignItem(item) => self.format_foreign_item(item),
288 pub fn format_foreign_mod(&mut self, fm: &ast::ForeignMod, span: Span) {
289 let item = Item::from_foreign_mod(fm, span, self.config);
290 self.format_item(&item);
293 fn format_foreign_item(&mut self, item: &ast::ForeignItem) {
294 let rewrite = item.rewrite(&self.get_context(), self.shape());
295 self.push_rewrite(item.span(), rewrite);
296 self.last_pos = item.span.hi();
306 inner_attrs: Option<&[ast::Attribute]>,
307 ) -> Option<String> {
308 let context = self.get_context();
310 let mut newline_brace = newline_for_brace(self.config, &fn_sig.generics.where_clause);
312 let (mut result, force_newline_brace) =
313 rewrite_fn_base(&context, indent, ident, fn_sig, span, newline_brace, true)?;
316 if self.config.brace_style() == BraceStyle::AlwaysNextLine || force_newline_brace
317 || last_line_width(&result) + 2 > self.shape().width
319 newline_brace = true;
320 } else if !result.contains('\n') {
321 newline_brace = false;
324 // Prepare for the function body by possibly adding a newline and
326 // FIXME we'll miss anything between the end of the signature and the
327 // start of the body, but we need more spans from the compiler to solve
330 result.push_str(&indent.to_string_with_newline(self.config));
335 self.single_line_fn(&result, block, inner_attrs)
336 .or_else(|| Some(result))
339 pub fn rewrite_required_fn(
343 sig: &ast::MethodSig,
344 generics: &ast::Generics,
346 ) -> Option<String> {
347 // Drop semicolon or it will be interpreted as comment.
348 let span = mk_sp(span.lo(), span.hi() - BytePos(1));
349 let context = self.get_context();
351 let (mut result, _) = rewrite_fn_base(
355 &FnSig::from_method_sig(sig, generics),
361 // Re-attach semicolon
371 inner_attrs: Option<&[ast::Attribute]>,
372 ) -> Option<String> {
373 if fn_str.contains('\n') || inner_attrs.map_or(false, |a| !a.is_empty()) {
377 let codemap = self.get_context().codemap;
379 if self.config.empty_item_single_line() && is_empty_block(block, None, codemap)
380 && self.block_indent.width() + fn_str.len() + 2 <= self.config.max_width()
382 return Some(format!("{}{{}}", fn_str));
385 if self.config.fn_single_line() && is_simple_block_stmt(block, None, codemap) {
387 if let Some(stmt) = block.stmts.first() {
388 match stmt_expr(stmt) {
390 let suffix = if semicolon_for_expr(&self.get_context(), e) {
396 format_expr(e, ExprType::Statement, &self.get_context(), self.shape())
398 .or_else(|| Some(self.snippet(e.span).to_owned()))
400 None => stmt.rewrite(&self.get_context(), self.shape()),
407 if let Some(res) = rewrite {
408 let width = self.block_indent.width() + fn_str.len() + res.len() + 4;
409 if !res.contains('\n') && width <= self.config.max_width() {
410 return Some(format!("{}{{ {} }}", fn_str, res));
418 pub fn visit_static(&mut self, static_parts: &StaticParts) {
419 let rewrite = rewrite_static(&self.get_context(), static_parts, self.block_indent);
420 self.push_rewrite(static_parts.span, rewrite);
423 pub fn visit_struct(&mut self, struct_parts: &StructParts) {
424 let is_tuple = struct_parts.def.is_tuple();
425 let rewrite = format_struct(&self.get_context(), struct_parts, self.block_indent, None)
426 .map(|s| if is_tuple { s + ";" } else { s });
427 self.push_rewrite(struct_parts.span, rewrite);
433 vis: &ast::Visibility,
434 enum_def: &ast::EnumDef,
435 generics: &ast::Generics,
438 let enum_header = format_header("enum ", ident, vis);
439 self.push_str(&enum_header);
441 let enum_snippet = self.snippet(span);
442 let brace_pos = enum_snippet.find_uncommented("{").unwrap();
443 let body_start = span.lo() + BytePos(brace_pos as u32 + 1);
444 let generics_str = format_generics(
447 self.config.brace_style(),
448 if enum_def.variants.is_empty() {
449 BracePos::ForceSameLine
454 mk_sp(span.lo(), body_start),
455 last_line_width(&enum_header),
457 self.push_str(&generics_str);
459 self.last_pos = body_start;
461 match self.format_variant_list(enum_def, body_start, span.hi()) {
462 Some(ref s) if enum_def.variants.is_empty() => self.push_str(s),
464 self.push_rewrite(mk_sp(body_start, span.hi()), rw);
465 self.block_indent = self.block_indent.block_unindent(self.config);
470 // Format the body of an enum definition
471 fn format_variant_list(
473 enum_def: &ast::EnumDef,
476 ) -> Option<String> {
477 if enum_def.variants.is_empty() {
478 let mut buffer = String::with_capacity(128);
480 let span = mk_sp(body_lo, body_hi - BytePos(1));
481 format_empty_struct_or_tuple(
491 let mut result = String::with_capacity(1024);
492 let original_offset = self.block_indent;
493 self.block_indent = self.block_indent.block_indent(self.config);
495 let itemize_list_with = |one_line_width: usize| {
497 self.snippet_provider,
498 enum_def.variants.iter(),
502 if !f.node.attrs.is_empty() {
503 f.node.attrs[0].span.lo()
509 |f| self.format_variant(f, one_line_width),
515 let mut items: Vec<_> =
516 itemize_list_with(self.config.width_heuristics().struct_variant_width);
517 // If one of the variants use multiple lines, use multi-lined formatting for all variants.
518 let has_multiline_variant = items.iter().any(|item| item.inner_as_ref().contains('\n'));
519 let has_single_line_variant = items.iter().any(|item| !item.inner_as_ref().contains('\n'));
520 if has_multiline_variant && has_single_line_variant {
521 items = itemize_list_with(0);
524 let shape = self.shape().sub_width(2)?;
525 let fmt = ListFormatting {
526 tactic: DefinitiveListTactic::Vertical,
528 trailing_separator: self.config.trailing_comma(),
529 separator_place: SeparatorPlace::Back,
531 ends_with_newline: true,
532 preserve_newline: true,
536 let list = write_list(&items, &fmt)?;
537 result.push_str(&list);
538 result.push_str(&original_offset.to_string_with_newline(self.config));
543 // Variant of an enum.
544 fn format_variant(&self, field: &ast::Variant, one_line_width: usize) -> Option<String> {
545 if contains_skip(&field.node.attrs) {
546 let lo = field.node.attrs[0].span.lo();
547 let span = mk_sp(lo, field.span.hi());
548 return Some(self.snippet(span).to_owned());
551 let context = self.get_context();
553 let shape = self.shape().sub_width(1)?;
554 let attrs_str = field.node.attrs.rewrite(&context, shape)?;
559 .map_or(field.span.lo(), |attr| attr.span.hi());
560 let span = mk_sp(lo, field.span.lo());
562 let variant_body = match field.node.data {
563 ast::VariantData::Tuple(..) | ast::VariantData::Struct(..) => format_struct(
565 &StructParts::from_variant(field),
567 Some(one_line_width),
569 ast::VariantData::Unit(..) => {
570 if let Some(ref expr) = field.node.disr_expr {
571 let lhs = format!("{} =", field.node.ident.name);
572 rewrite_assign_rhs(&context, lhs, &**expr, shape)?
574 field.node.ident.name.to_string()
579 combine_strs_with_missing_comments(&context, &attrs_str, &variant_body, span, shape, false)
582 fn visit_impl_items(&mut self, items: &[ast::ImplItem]) {
583 if self.get_context().config.reorder_impl_items() {
584 // Create visitor for each items, then reorder them.
585 let mut buffer = vec![];
587 self.visit_impl_item(item);
588 buffer.push((self.buffer.clone(), item.clone()));
591 // type -> const -> macro -> method
592 use ast::ImplItemKind::*;
593 fn need_empty_line(a: &ast::ImplItemKind, b: &ast::ImplItemKind) -> bool {
595 (Type(..), Type(..)) | (Const(..), Const(..)) => false,
600 buffer.sort_by(|(_, a), (_, b)| match (&a.node, &b.node) {
601 (Type(..), _) => Ordering::Less,
602 (_, Type(..)) => Ordering::Greater,
603 (Const(..), _) => Ordering::Less,
604 (_, Const(..)) => Ordering::Greater,
605 (Macro(..), _) => Ordering::Less,
606 (_, Macro(..)) => Ordering::Greater,
607 _ => a.span.lo().cmp(&b.span.lo()),
609 let mut prev_kind = None;
610 for (buf, item) in buffer {
611 // Make sure that there are at least a single empty line between
612 // different impl items.
615 .map_or(false, |prev_kind| need_empty_line(prev_kind, &item.node))
619 let indent_str = self.block_indent.to_string_with_newline(self.config);
620 self.push_str(&indent_str);
621 self.push_str(buf.trim());
622 prev_kind = Some(item.node.clone());
626 self.visit_impl_item(item);
633 context: &RewriteContext,
636 where_span_end: Option<BytePos>,
637 ) -> Option<String> {
638 if let ast::ItemKind::Impl(_, _, _, ref generics, _, ref self_ty, ref items) = item.node {
639 let mut result = String::with_capacity(128);
640 let ref_and_type = format_impl_ref_and_type(context, item, offset)?;
641 let sep = offset.to_string_with_newline(context.config);
642 result.push_str(&ref_and_type);
644 let where_budget = if result.contains('\n') {
645 context.config.max_width()
647 context.budget(last_line_width(&result))
649 let option = WhereClauseOption::snuggled(&ref_and_type);
650 let where_clause_str = rewrite_where_clause(
652 &generics.where_clause,
653 context.config.brace_style(),
654 Shape::legacy(where_budget, offset.block_only()),
663 // If there is no where clause, we may have missing comments between the trait name and
664 // the opening brace.
665 if generics.where_clause.predicates.is_empty() {
666 if let Some(hi) = where_span_end {
667 match recover_missing_comment_in_span(
668 mk_sp(self_ty.span.hi(), hi),
669 Shape::indented(offset, context.config),
671 last_line_width(&result),
673 Some(ref missing_comment) if !missing_comment.is_empty() => {
674 result.push_str(missing_comment);
681 if is_impl_single_line(context, items, &result, &where_clause_str, item)? {
682 result.push_str(&where_clause_str);
683 if where_clause_str.contains('\n') || last_line_contains_single_line_comment(&result) {
684 result.push_str(&format!("{}{{{}}}", &sep, &sep));
686 result.push_str(" {}");
691 if !where_clause_str.is_empty() && !where_clause_str.contains('\n') {
692 let width = offset.block_indent + context.config.tab_spaces() - 1;
693 let where_indent = Indent::new(0, width);
694 result.push_str(&where_indent.to_string_with_newline(context.config));
696 result.push_str(&where_clause_str);
698 let need_newline = last_line_contains_single_line_comment(&result) || result.contains('\n');
699 match context.config.brace_style() {
700 _ if need_newline => result.push_str(&sep),
701 BraceStyle::AlwaysNextLine => result.push_str(&sep),
702 BraceStyle::PreferSameLine => result.push(' '),
703 BraceStyle::SameLineWhere => {
704 if !where_clause_str.is_empty() {
705 result.push_str(&sep);
714 let snippet = context.snippet(item.span);
715 let open_pos = snippet.find_uncommented("{")? + 1;
717 if !items.is_empty() || contains_comment(&snippet[open_pos..]) {
718 let mut visitor = FmtVisitor::from_context(context);
719 let item_indent = offset.block_only().block_indent(context.config);
720 visitor.block_indent = item_indent;
721 visitor.last_pos = item.span.lo() + BytePos(open_pos as u32);
723 visitor.visit_attrs(&item.attrs, ast::AttrStyle::Inner);
724 visitor.visit_impl_items(items);
726 visitor.format_missing(item.span.hi() - BytePos(1));
728 let inner_indent_str = visitor.block_indent.to_string_with_newline(context.config);
729 let outer_indent_str = offset.block_only().to_string_with_newline(context.config);
731 result.push_str(&inner_indent_str);
732 result.push_str(visitor.buffer.to_string().trim());
733 result.push_str(&outer_indent_str);
736 if result.ends_with('{') {
737 result.push_str(&sep);
747 fn is_impl_single_line(
748 context: &RewriteContext,
749 items: &[ast::ImplItem],
751 where_clause_str: &str,
754 let snippet = context.snippet(item.span);
755 let open_pos = snippet.find_uncommented("{")? + 1;
758 context.config.empty_item_single_line() && items.is_empty() && !result.contains('\n')
759 && result.len() + where_clause_str.len() <= context.config.max_width()
760 && !contains_comment(&snippet[open_pos..]),
764 fn format_impl_ref_and_type(
765 context: &RewriteContext,
768 ) -> Option<String> {
769 if let ast::ItemKind::Impl(
779 let mut result = String::with_capacity(128);
781 result.push_str(&format_visibility(&item.vis));
782 result.push_str(format_defaultness(defaultness));
783 result.push_str(format_unsafety(unsafety));
785 let lo = context.snippet_provider.span_after(item.span, "impl");
786 let hi = match *trait_ref {
787 Some(ref tr) => tr.path.span.lo(),
788 None => self_ty.span.lo(),
790 let shape = generics_shape_from_config(
792 Shape::indented(offset + last_line_width(&result), context.config),
795 let generics_str = rewrite_generics(context, "impl", generics, shape, mk_sp(lo, hi))?;
796 result.push_str(&generics_str);
798 let polarity_str = if polarity == ast::ImplPolarity::Negative {
804 if let Some(ref trait_ref) = *trait_ref {
805 let result_len = last_line_width(&result);
806 result.push_str(&rewrite_trait_ref(
815 // Try to put the self type in a single line.
817 let trait_ref_overhead = if trait_ref.is_some() { 4 } else { 0 };
818 let curly_brace_overhead = if generics.where_clause.predicates.is_empty() {
819 // If there is no where clause adapt budget for type formatting to take space and curly
820 // brace into account.
821 match context.config.brace_style() {
822 BraceStyle::AlwaysNextLine => 0,
828 let used_space = last_line_width(&result) + trait_ref_overhead + curly_brace_overhead;
829 // 1 = space before the type.
830 let budget = context.budget(used_space + 1);
831 if let Some(self_ty_str) = self_ty.rewrite(context, Shape::legacy(budget, offset)) {
832 if !self_ty_str.contains('\n') {
833 if trait_ref.is_some() {
834 result.push_str(" for ");
838 result.push_str(&self_ty_str);
843 // Couldn't fit the self type on a single line, put it on a new line.
845 // Add indentation of one additional tab.
846 let new_line_offset = offset.block_indent(context.config);
847 result.push_str(&new_line_offset.to_string(context.config));
848 if trait_ref.is_some() {
849 result.push_str("for ");
851 let budget = context.budget(last_line_width(&result));
852 let type_offset = match context.config.indent_style() {
853 IndentStyle::Visual => new_line_offset + trait_ref_overhead,
854 IndentStyle::Block => new_line_offset,
856 result.push_str(&*self_ty.rewrite(context, Shape::legacy(budget, type_offset))?);
863 fn rewrite_trait_ref(
864 context: &RewriteContext,
865 trait_ref: &ast::TraitRef,
869 ) -> Option<String> {
870 // 1 = space between generics and trait_ref
871 let used_space = 1 + polarity_str.len() + result_len;
872 let shape = Shape::indented(offset + used_space, context.config);
873 if let Some(trait_ref_str) = trait_ref.rewrite(context, shape) {
874 if !trait_ref_str.contains('\n') {
875 return Some(format!(" {}{}", polarity_str, &trait_ref_str));
878 // We could not make enough space for trait_ref, so put it on new line.
879 let offset = offset.block_indent(context.config);
880 let shape = Shape::indented(offset, context.config);
881 let trait_ref_str = trait_ref.rewrite(context, shape)?;
884 &offset.to_string_with_newline(context.config),
890 pub struct StructParts<'a> {
893 vis: &'a ast::Visibility,
894 def: &'a ast::VariantData,
895 generics: Option<&'a ast::Generics>,
899 impl<'a> StructParts<'a> {
900 fn format_header(&self) -> String {
901 format_header(self.prefix, self.ident, self.vis)
904 fn from_variant(variant: &'a ast::Variant) -> Self {
907 ident: variant.node.ident,
908 vis: &DEFAULT_VISIBILITY,
909 def: &variant.node.data,
915 pub fn from_item(item: &'a ast::Item) -> Self {
916 let (prefix, def, generics) = match item.node {
917 ast::ItemKind::Struct(ref def, ref generics) => ("struct ", def, generics),
918 ast::ItemKind::Union(ref def, ref generics) => ("union ", def, generics),
926 generics: Some(generics),
933 context: &RewriteContext,
934 struct_parts: &StructParts,
936 one_line_width: Option<usize>,
937 ) -> Option<String> {
938 match *struct_parts.def {
939 ast::VariantData::Unit(..) => format_unit_struct(context, struct_parts, offset),
940 ast::VariantData::Tuple(ref fields, _) => {
941 format_tuple_struct(context, struct_parts, fields, offset)
943 ast::VariantData::Struct(ref fields, _) => {
944 format_struct_struct(context, struct_parts, fields, offset, one_line_width)
949 pub fn format_trait(context: &RewriteContext, item: &ast::Item, offset: Indent) -> Option<String> {
950 if let ast::ItemKind::Trait(
954 ref type_param_bounds,
958 let mut result = String::with_capacity(128);
959 let header = format!(
961 format_auto(is_auto),
962 format_visibility(&item.vis),
963 format_unsafety(unsafety),
965 result.push_str(&header);
967 let body_lo = context.snippet_provider.span_after(item.span, "{");
969 let shape = Shape::indented(offset, context.config).offset_left(result.len())?;
970 let generics_str = rewrite_generics(
972 &item.ident.to_string(),
975 mk_sp(item.span.lo(), body_lo),
977 result.push_str(&generics_str);
979 // FIXME(#2055): rustfmt fails to format when there are comments between trait bounds.
980 if !type_param_bounds.is_empty() {
981 let ident_hi = context
983 .span_after(item.span, &format!("{}", item.ident));
984 let bound_hi = type_param_bounds.last().unwrap().span().hi();
985 let snippet = context.snippet(mk_sp(ident_hi, bound_hi));
986 if contains_comment(snippet) {
990 if !type_param_bounds.is_empty() {
991 result = rewrite_assign_rhs_with(
994 &TraitTyParamBounds::new(type_param_bounds),
996 RhsTactics::ForceNextLine,
1000 // Rewrite where clause.
1001 if !generics.where_clause.predicates.is_empty() {
1002 let where_density = if context.config.indent_style() == IndentStyle::Block {
1008 let where_budget = context.budget(last_line_width(&result));
1009 let pos_before_where = if type_param_bounds.is_empty() {
1010 generics.where_clause.span.lo()
1012 type_param_bounds[type_param_bounds.len() - 1].span().hi()
1014 let option = WhereClauseOption::snuggled(&generics_str);
1015 let where_clause_str = rewrite_where_clause(
1017 &generics.where_clause,
1018 context.config.brace_style(),
1019 Shape::legacy(where_budget, offset.block_only()),
1027 // If the where clause cannot fit on the same line,
1028 // put the where clause on a new line
1029 if !where_clause_str.contains('\n')
1030 && last_line_width(&result) + where_clause_str.len() + offset.width()
1031 > context.config.comment_width()
1033 let width = offset.block_indent + context.config.tab_spaces() - 1;
1034 let where_indent = Indent::new(0, width);
1035 result.push_str(&where_indent.to_string_with_newline(context.config));
1037 result.push_str(&where_clause_str);
1039 let item_snippet = context.snippet(item.span);
1040 if let Some(lo) = item_snippet.find('/') {
1042 let comment_hi = body_lo - BytePos(1);
1043 let comment_lo = item.span.lo() + BytePos(lo as u32);
1044 if comment_lo < comment_hi {
1045 match recover_missing_comment_in_span(
1046 mk_sp(comment_lo, comment_hi),
1047 Shape::indented(offset, context.config),
1049 last_line_width(&result),
1051 Some(ref missing_comment) if !missing_comment.is_empty() => {
1052 result.push_str(missing_comment);
1060 match context.config.brace_style() {
1061 _ if last_line_contains_single_line_comment(&result)
1062 || last_line_width(&result) + 2 > context.budget(offset.width()) =>
1064 result.push_str(&offset.to_string_with_newline(context.config));
1066 BraceStyle::AlwaysNextLine => {
1067 result.push_str(&offset.to_string_with_newline(context.config));
1069 BraceStyle::PreferSameLine => result.push(' '),
1070 BraceStyle::SameLineWhere => {
1071 if result.contains('\n')
1072 || (!generics.where_clause.predicates.is_empty() && !trait_items.is_empty())
1074 result.push_str(&offset.to_string_with_newline(context.config));
1082 let snippet = context.snippet(item.span);
1083 let open_pos = snippet.find_uncommented("{")? + 1;
1085 if !trait_items.is_empty() || contains_comment(&snippet[open_pos..]) {
1086 let mut visitor = FmtVisitor::from_context(context);
1087 visitor.block_indent = offset.block_only().block_indent(context.config);
1088 visitor.last_pos = item.span.lo() + BytePos(open_pos as u32);
1090 for item in trait_items {
1091 visitor.visit_trait_item(item);
1094 visitor.format_missing(item.span.hi() - BytePos(1));
1096 let inner_indent_str = visitor.block_indent.to_string_with_newline(context.config);
1097 let outer_indent_str = offset.block_only().to_string_with_newline(context.config);
1099 result.push_str(&inner_indent_str);
1100 result.push_str(visitor.buffer.to_string().trim());
1101 result.push_str(&outer_indent_str);
1102 } else if result.contains('\n') {
1113 pub fn format_trait_alias(
1114 context: &RewriteContext,
1116 generics: &ast::Generics,
1117 ty_param_bounds: &ast::TyParamBounds,
1119 ) -> Option<String> {
1120 let alias = ident.name.as_str();
1121 // 6 = "trait ", 2 = " ="
1122 let g_shape = shape.offset_left(6)?.sub_width(2)?;
1123 let generics_str = rewrite_generics(context, &alias, generics, g_shape, generics.span)?;
1124 let lhs = format!("trait {} =", generics_str);
1126 rewrite_assign_rhs(context, lhs, ty_param_bounds, shape.sub_width(1)?).map(|s| s + ";")
1129 fn format_unit_struct(context: &RewriteContext, p: &StructParts, offset: Indent) -> Option<String> {
1130 let header_str = format_header(p.prefix, p.ident, p.vis);
1131 let generics_str = if let Some(generics) = p.generics {
1132 let hi = if generics.where_clause.predicates.is_empty() {
1135 generics.where_clause.span.hi()
1140 context.config.brace_style(),
1143 mk_sp(generics.span.lo(), hi),
1144 last_line_width(&header_str),
1149 Some(format!("{}{};", header_str, generics_str))
1152 pub fn format_struct_struct(
1153 context: &RewriteContext,
1154 struct_parts: &StructParts,
1155 fields: &[ast::StructField],
1157 one_line_width: Option<usize>,
1158 ) -> Option<String> {
1159 let mut result = String::with_capacity(1024);
1160 let span = struct_parts.span;
1162 let header_str = struct_parts.format_header();
1163 result.push_str(&header_str);
1165 let header_hi = span.lo() + BytePos(header_str.len() as u32);
1166 let body_lo = context.snippet_provider.span_after(span, "{");
1168 let generics_str = match struct_parts.generics {
1169 Some(g) => format_generics(
1172 context.config.brace_style(),
1173 if fields.is_empty() {
1174 BracePos::ForceSameLine
1179 mk_sp(header_hi, body_lo),
1180 last_line_width(&result),
1183 // 3 = ` {}`, 2 = ` {`.
1184 let overhead = if fields.is_empty() { 3 } else { 2 };
1185 if (context.config.brace_style() == BraceStyle::AlwaysNextLine && !fields.is_empty())
1186 || context.config.max_width() < overhead + result.len()
1188 format!("\n{}{{", offset.block_only().to_string(context.config))
1195 let overhead = if fields.is_empty() { 1 } else { 0 };
1196 let total_width = result.len() + generics_str.len() + overhead;
1197 if !generics_str.is_empty() && !generics_str.contains('\n')
1198 && total_width > context.config.max_width()
1201 result.push_str(&offset.to_string(context.config));
1202 result.push_str(generics_str.trim_left());
1204 result.push_str(&generics_str);
1207 if fields.is_empty() {
1208 let inner_span = mk_sp(body_lo, span.hi() - BytePos(1));
1209 format_empty_struct_or_tuple(context, inner_span, offset, &mut result, "", "}");
1210 return Some(result);
1214 let one_line_budget = context.budget(result.len() + 3 + offset.width());
1215 let one_line_budget =
1216 one_line_width.map_or(0, |one_line_width| min(one_line_width, one_line_budget));
1218 let items_str = rewrite_with_alignment(
1221 Shape::indented(offset, context.config).sub_width(1)?,
1222 mk_sp(body_lo, span.hi()),
1226 if !items_str.contains('\n') && !result.contains('\n') && items_str.len() <= one_line_budget
1227 && !last_line_contains_single_line_comment(&items_str)
1229 Some(format!("{} {} }}", result, items_str))
1235 .block_indent(context.config)
1236 .to_string(context.config),
1238 offset.to_string(context.config)
1243 fn get_bytepos_after_visibility(vis: &ast::Visibility, default_span: Span) -> BytePos {
1245 ast::VisibilityKind::Crate(..) | ast::VisibilityKind::Restricted { .. } => vis.span.hi(),
1246 _ => default_span.lo(),
1250 // Format tuple or struct without any fields. We need to make sure that the comments
1251 // inside the delimiters are preserved.
1252 fn format_empty_struct_or_tuple(
1253 context: &RewriteContext,
1256 result: &mut String,
1260 // 3 = " {}" or "();"
1261 let used_width = last_line_used_width(&result, offset.width()) + 3;
1262 if used_width > context.config.max_width() {
1263 result.push_str(&offset.to_string_with_newline(context.config))
1265 result.push_str(opener);
1266 match rewrite_missing_comment(span, Shape::indented(offset, context.config), context) {
1267 Some(ref s) if s.is_empty() => (),
1269 if !is_single_line(s) || first_line_contains_single_line_comment(s) {
1270 let nested_indent_str = offset
1271 .block_indent(context.config)
1272 .to_string_with_newline(context.config);
1273 result.push_str(&nested_indent_str);
1276 if last_line_contains_single_line_comment(s) {
1277 result.push_str(&offset.to_string_with_newline(context.config));
1280 None => result.push_str(context.snippet(span)),
1282 result.push_str(closer);
1285 fn format_tuple_struct(
1286 context: &RewriteContext,
1287 struct_parts: &StructParts,
1288 fields: &[ast::StructField],
1290 ) -> Option<String> {
1291 let mut result = String::with_capacity(1024);
1292 let span = struct_parts.span;
1294 let header_str = struct_parts.format_header();
1295 result.push_str(&header_str);
1297 let body_lo = if fields.is_empty() {
1298 let lo = get_bytepos_after_visibility(struct_parts.vis, span);
1301 .span_after(mk_sp(lo, span.hi()), "(")
1305 let body_hi = if fields.is_empty() {
1308 .span_after(mk_sp(body_lo, span.hi()), ")")
1310 // This is a dirty hack to work around a missing `)` from the span of the last field.
1311 let last_arg_span = fields[fields.len() - 1].span;
1312 if context.snippet(last_arg_span).ends_with(')') {
1317 .span_after(mk_sp(last_arg_span.hi(), span.hi()), ")")
1321 let where_clause_str = match struct_parts.generics {
1323 let budget = context.budget(last_line_width(&header_str));
1324 let shape = Shape::legacy(budget, offset);
1325 let g_span = mk_sp(span.lo(), body_lo);
1326 let generics_str = rewrite_generics(context, "", generics, shape, g_span)?;
1327 result.push_str(&generics_str);
1329 let where_budget = context.budget(last_line_width(&result));
1330 let option = WhereClauseOption::new(true, false);
1331 rewrite_where_clause(
1333 &generics.where_clause,
1334 context.config.brace_style(),
1335 Shape::legacy(where_budget, offset.block_only()),
1336 Density::Compressed,
1344 None => "".to_owned(),
1347 if fields.is_empty() {
1348 let body_hi = context
1350 .span_before(mk_sp(body_lo, span.hi()), ")");
1351 let inner_span = mk_sp(body_lo, body_hi);
1352 format_empty_struct_or_tuple(context, inner_span, offset, &mut result, "(", ")");
1354 let shape = Shape::indented(offset, context.config).sub_width(1)?;
1355 let fields = &fields.iter().collect::<Vec<_>>();
1356 result = overflow::rewrite_with_parens(
1362 context.config.width_heuristics().fn_call_width,
1367 if !where_clause_str.is_empty() && !where_clause_str.contains('\n')
1368 && (result.contains('\n')
1369 || offset.block_indent + result.len() + where_clause_str.len() + 1
1370 > context.config.max_width())
1372 // We need to put the where clause on a new line, but we didn't
1373 // know that earlier, so the where clause will not be indented properly.
1376 .push_str(&(offset.block_only() + (context.config.tab_spaces() - 1))
1377 .to_string(context.config));
1379 result.push_str(&where_clause_str);
1384 pub fn rewrite_type_alias(
1385 context: &RewriteContext,
1389 generics: &ast::Generics,
1390 vis: &ast::Visibility,
1392 ) -> Option<String> {
1393 let mut result = String::with_capacity(128);
1395 result.push_str(&format_visibility(vis));
1396 result.push_str("type ");
1399 let g_shape = Shape::indented(indent, context.config)
1400 .offset_left(result.len())?
1403 context.snippet_provider.span_after(span, "type"),
1406 let generics_str = rewrite_generics(context, &ident.to_string(), generics, g_shape, g_span)?;
1407 result.push_str(&generics_str);
1409 let where_budget = context.budget(last_line_width(&result));
1410 let option = WhereClauseOption::snuggled(&result);
1411 let where_clause_str = rewrite_where_clause(
1413 &generics.where_clause,
1414 context.config.brace_style(),
1415 Shape::legacy(where_budget, indent),
1423 result.push_str(&where_clause_str);
1424 if where_clause_str.is_empty() {
1425 result.push_str(" =");
1427 result.push_str(&format!(
1429 indent.to_string_with_newline(context.config)
1434 let ty_shape = Shape::indented(indent, context.config).sub_width(1)?;
1435 rewrite_assign_rhs(context, result, ty, ty_shape).map(|s| s + ";")
1438 fn type_annotation_spacing(config: &Config) -> (&str, &str) {
1440 if config.space_before_colon() { " " } else { "" },
1441 if config.space_after_colon() { " " } else { "" },
1445 pub fn rewrite_struct_field_prefix(
1446 context: &RewriteContext,
1447 field: &ast::StructField,
1448 ) -> Option<String> {
1449 let vis = format_visibility(&field.vis);
1450 let type_annotation_spacing = type_annotation_spacing(context.config);
1451 Some(match field.ident {
1452 Some(name) => format!("{}{}{}:", vis, name, type_annotation_spacing.0),
1453 None => format!("{}", vis),
1457 impl Rewrite for ast::StructField {
1458 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
1459 rewrite_struct_field(context, self, shape, 0)
1463 pub fn rewrite_struct_field(
1464 context: &RewriteContext,
1465 field: &ast::StructField,
1467 lhs_max_width: usize,
1468 ) -> Option<String> {
1469 if contains_skip(&field.attrs) {
1470 return Some(context.snippet(field.span()).to_owned());
1473 let type_annotation_spacing = type_annotation_spacing(context.config);
1474 let prefix = rewrite_struct_field_prefix(context, field)?;
1476 let attrs_str = field.attrs.rewrite(context, shape)?;
1477 let attrs_extendable = field.ident.is_none() && is_attributes_extendable(&attrs_str);
1478 let missing_span = if field.attrs.is_empty() {
1479 mk_sp(field.span.lo(), field.span.lo())
1481 mk_sp(field.attrs.last().unwrap().span.hi(), field.span.lo())
1483 let mut spacing = String::from(if field.ident.is_some() {
1484 type_annotation_spacing.1
1488 // Try to put everything on a single line.
1489 let attr_prefix = combine_strs_with_missing_comments(
1497 let overhead = last_line_width(&attr_prefix);
1498 let lhs_offset = lhs_max_width.checked_sub(overhead).unwrap_or(0);
1499 for _ in 0..lhs_offset {
1502 // In this extreme case we will be missing a space betweeen an attribute and a field.
1503 if prefix.is_empty() && !attrs_str.is_empty() && attrs_extendable && spacing.is_empty() {
1507 .offset_left(overhead + spacing.len())
1508 .and_then(|ty_shape| field.ty.rewrite(context, ty_shape));
1509 if let Some(ref ty) = orig_ty {
1510 if !ty.contains('\n') {
1511 return Some(attr_prefix + &spacing + ty);
1515 let is_prefix_empty = prefix.is_empty();
1516 // We must use multiline. We are going to put attributes and a field on different lines.
1517 let field_str = rewrite_assign_rhs(context, prefix, &*field.ty, shape)?;
1518 // Remove a leading white-space from `rewrite_assign_rhs()` when rewriting a tuple struct.
1519 let field_str = if is_prefix_empty {
1520 field_str.trim_left()
1524 combine_strs_with_missing_comments(context, &attrs_str, field_str, missing_span, shape, false)
1527 pub struct StaticParts<'a> {
1529 vis: &'a ast::Visibility,
1532 mutability: ast::Mutability,
1533 expr_opt: Option<&'a ptr::P<ast::Expr>>,
1534 defaultness: Option<ast::Defaultness>,
1538 impl<'a> StaticParts<'a> {
1539 pub fn from_item(item: &'a ast::Item) -> Self {
1540 let (prefix, ty, mutability, expr) = match item.node {
1541 ast::ItemKind::Static(ref ty, mutability, ref expr) => ("static", ty, mutability, expr),
1542 ast::ItemKind::Const(ref ty, ref expr) => {
1543 ("const", ty, ast::Mutability::Immutable, expr)
1545 _ => unreachable!(),
1553 expr_opt: Some(expr),
1559 pub fn from_trait_item(ti: &'a ast::TraitItem) -> Self {
1560 let (ty, expr_opt) = match ti.node {
1561 ast::TraitItemKind::Const(ref ty, ref expr_opt) => (ty, expr_opt),
1562 _ => unreachable!(),
1566 vis: &DEFAULT_VISIBILITY,
1569 mutability: ast::Mutability::Immutable,
1570 expr_opt: expr_opt.as_ref(),
1576 pub fn from_impl_item(ii: &'a ast::ImplItem) -> Self {
1577 let (ty, expr) = match ii.node {
1578 ast::ImplItemKind::Const(ref ty, ref expr) => (ty, expr),
1579 _ => unreachable!(),
1586 mutability: ast::Mutability::Immutable,
1587 expr_opt: Some(expr),
1588 defaultness: Some(ii.defaultness),
1595 context: &RewriteContext,
1596 static_parts: &StaticParts,
1598 ) -> Option<String> {
1599 let colon = colon_spaces(
1600 context.config.space_before_colon(),
1601 context.config.space_after_colon(),
1603 let mut prefix = format!(
1605 format_visibility(static_parts.vis),
1606 static_parts.defaultness.map_or("", format_defaultness),
1607 static_parts.prefix,
1608 format_mutability(static_parts.mutability),
1614 Shape::indented(offset.block_only(), context.config).offset_left(prefix.len() + 2)?;
1615 let ty_str = match static_parts.ty.rewrite(context, ty_shape) {
1616 Some(ty_str) => ty_str,
1618 if prefix.ends_with(' ') {
1621 let nested_indent = offset.block_indent(context.config);
1622 let nested_shape = Shape::indented(nested_indent, context.config);
1623 let ty_str = static_parts.ty.rewrite(context, nested_shape)?;
1626 nested_indent.to_string_with_newline(context.config),
1632 if let Some(expr) = static_parts.expr_opt {
1633 let lhs = format!("{}{} =", prefix, ty_str);
1635 let remaining_width = context.budget(offset.block_indent + 1);
1640 Shape::legacy(remaining_width, offset.block_only()),
1641 ).and_then(|res| recover_comment_removed(res, static_parts.span, context))
1642 .map(|s| if s.ends_with(';') { s } else { s + ";" })
1644 Some(format!("{}{};", prefix, ty_str))
1648 pub fn rewrite_associated_type(
1650 ty_opt: Option<&ptr::P<ast::Ty>>,
1651 ty_param_bounds_opt: Option<&ast::TyParamBounds>,
1652 context: &RewriteContext,
1654 ) -> Option<String> {
1655 let prefix = format!("type {}", ident);
1657 let type_bounds_str = if let Some(bounds) = ty_param_bounds_opt {
1658 if bounds.is_empty() {
1662 let shape = Shape::indented(indent, context.config).offset_left(prefix.len() + 2)?;
1663 bounds.rewrite(context, shape).map(|s| format!(": {}", s))?
1669 if let Some(ty) = ty_opt {
1671 let shape = Shape::indented(indent, context.config).sub_width(1)?;
1672 let lhs = format!("{}{} =", prefix, type_bounds_str);
1673 rewrite_assign_rhs(context, lhs, &**ty, shape).map(|s| s + ";")
1675 Some(format!("{}{};", prefix, type_bounds_str))
1679 pub fn rewrite_associated_impl_type(
1681 defaultness: ast::Defaultness,
1682 ty_opt: Option<&ptr::P<ast::Ty>>,
1683 ty_param_bounds_opt: Option<&ast::TyParamBounds>,
1684 context: &RewriteContext,
1686 ) -> Option<String> {
1687 let result = rewrite_associated_type(ident, ty_opt, ty_param_bounds_opt, context, indent)?;
1690 ast::Defaultness::Default => Some(format!("default {}", result)),
1695 impl Rewrite for ast::FunctionRetTy {
1696 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
1698 ast::FunctionRetTy::Default(_) => Some(String::new()),
1699 ast::FunctionRetTy::Ty(ref ty) => {
1700 let inner_width = shape.width.checked_sub(3)?;
1701 ty.rewrite(context, Shape::legacy(inner_width, shape.indent + 3))
1702 .map(|r| format!("-> {}", r))
1708 fn is_empty_infer(context: &RewriteContext, ty: &ast::Ty) -> bool {
1710 ast::TyKind::Infer => {
1711 let original = context.snippet(ty.span);
1718 impl Rewrite for ast::Arg {
1719 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
1720 if is_named_arg(self) {
1721 let mut result = self.pat
1722 .rewrite(context, Shape::legacy(shape.width, shape.indent))?;
1724 if !is_empty_infer(context, &*self.ty) {
1725 if context.config.space_before_colon() {
1726 result.push_str(" ");
1728 result.push_str(":");
1729 if context.config.space_after_colon() {
1730 result.push_str(" ");
1732 let overhead = last_line_width(&result);
1733 let max_width = shape.width.checked_sub(overhead)?;
1734 let ty_str = self.ty
1735 .rewrite(context, Shape::legacy(max_width, shape.indent))?;
1736 result.push_str(&ty_str);
1741 self.ty.rewrite(context, shape)
1746 fn rewrite_explicit_self(
1747 explicit_self: &ast::ExplicitSelf,
1749 context: &RewriteContext,
1750 ) -> Option<String> {
1751 match explicit_self.node {
1752 ast::SelfKind::Region(lt, m) => {
1753 let mut_str = format_mutability(m);
1756 let lifetime_str = l.rewrite(
1758 Shape::legacy(context.config.max_width(), Indent::empty()),
1760 Some(format!("&{} {}self", lifetime_str, mut_str))
1762 None => Some(format!("&{}self", mut_str)),
1765 ast::SelfKind::Explicit(ref ty, _) => {
1766 assert!(!args.is_empty(), "&[ast::Arg] shouldn't be empty.");
1768 let mutability = explicit_self_mutability(&args[0]);
1769 let type_str = ty.rewrite(
1771 Shape::legacy(context.config.max_width(), Indent::empty()),
1776 format_mutability(mutability),
1780 ast::SelfKind::Value(_) => {
1781 assert!(!args.is_empty(), "&[ast::Arg] shouldn't be empty.");
1783 let mutability = explicit_self_mutability(&args[0]);
1785 Some(format!("{}self", format_mutability(mutability)))
1790 // Hacky solution caused by absence of `Mutability` in `SelfValue` and
1791 // `SelfExplicit` variants of `ast::ExplicitSelf_`.
1792 fn explicit_self_mutability(arg: &ast::Arg) -> ast::Mutability {
1793 if let ast::PatKind::Ident(ast::BindingMode::ByValue(mutability), _, _) = arg.pat.node {
1800 pub fn span_lo_for_arg(arg: &ast::Arg) -> BytePos {
1801 if is_named_arg(arg) {
1808 pub fn span_hi_for_arg(context: &RewriteContext, arg: &ast::Arg) -> BytePos {
1810 ast::TyKind::Infer if context.snippet(arg.ty.span) == "_" => arg.ty.span.hi(),
1811 ast::TyKind::Infer if is_named_arg(arg) => arg.pat.span.hi(),
1812 _ => arg.ty.span.hi(),
1816 pub fn is_named_arg(arg: &ast::Arg) -> bool {
1817 if let ast::PatKind::Ident(_, ident, _) = arg.pat.node {
1818 ident != symbol::keywords::Invalid.ident()
1824 // Return type is (result, force_new_line_for_brace)
1826 context: &RewriteContext,
1831 newline_brace: bool,
1833 ) -> Option<(String, bool)> {
1834 let mut force_new_line_for_brace = false;
1836 let where_clause = &fn_sig.generics.where_clause;
1838 let mut result = String::with_capacity(1024);
1839 result.push_str(&fn_sig.to_str(context));
1842 result.push_str("fn ");
1845 let overhead = if has_body && !newline_brace {
1852 let used_width = last_line_used_width(&result, indent.width());
1853 let one_line_budget = context.budget(used_width + overhead);
1855 width: one_line_budget,
1859 let fd = fn_sig.decl;
1860 let g_span = mk_sp(span.lo(), fd.output.span().lo());
1862 rewrite_generics(context, &ident.to_string(), fn_sig.generics, shape, g_span)?;
1863 result.push_str(&generics_str);
1865 let snuggle_angle_bracket = generics_str
1868 .map_or(false, |l| l.trim_left().len() == 1);
1870 // Note that the width and indent don't really matter, we'll re-layout the
1871 // return type later anyway.
1872 let ret_str = fd.output
1873 .rewrite(context, Shape::indented(indent, context.config))?;
1875 let multi_line_ret_str = ret_str.contains('\n');
1876 let ret_str_len = if multi_line_ret_str { 0 } else { ret_str.len() };
1879 let (one_line_budget, multi_line_budget, mut arg_indent) = compute_budgets_for_args(
1890 "rewrite_fn_base: one_line_budget: {}, multi_line_budget: {}, arg_indent: {:?}",
1891 one_line_budget, multi_line_budget, arg_indent
1894 // Check if vertical layout was forced.
1895 if one_line_budget == 0 {
1896 if snuggle_angle_bracket {
1899 result.push_str("(");
1900 if context.config.indent_style() == IndentStyle::Visual {
1901 result.push_str(&arg_indent.to_string_with_newline(context.config));
1907 if context.config.spaces_within_parens_and_brackets() && !fd.inputs.is_empty()
1908 && result.ends_with('(')
1913 // Skip `pub(crate)`.
1914 let lo_after_visibility = get_bytepos_after_visibility(&fn_sig.visibility, span);
1915 // A conservative estimation, to goal is to be over all parens in generics
1916 let args_start = fn_sig
1921 .map_or(lo_after_visibility, |param| param.span().hi());
1922 let args_end = if fd.inputs.is_empty() {
1925 .span_after(mk_sp(args_start, span.hi()), ")")
1927 let last_span = mk_sp(fd.inputs[fd.inputs.len() - 1].span().hi(), span.hi());
1928 context.snippet_provider.span_after(last_span, ")")
1930 let args_span = mk_sp(
1933 .span_after(mk_sp(args_start, span.hi()), "("),
1936 let arg_str = rewrite_args(
1939 fd.get_self().as_ref(),
1946 generics_str.contains('\n'),
1949 let put_args_in_block = match context.config.indent_style() {
1950 IndentStyle::Block => arg_str.contains('\n') || arg_str.len() > one_line_budget,
1952 } && !fd.inputs.is_empty();
1954 let mut args_last_line_contains_comment = false;
1955 if put_args_in_block {
1956 arg_indent = indent.block_indent(context.config);
1957 result.push_str(&arg_indent.to_string_with_newline(context.config));
1958 result.push_str(&arg_str);
1959 result.push_str(&indent.to_string_with_newline(context.config));
1962 result.push_str(&arg_str);
1963 let used_width = last_line_used_width(&result, indent.width()) + first_line_width(&ret_str);
1964 // Put the closing brace on the next line if it overflows the max width.
1966 if fd.inputs.is_empty() && used_width + 1 > context.config.max_width() {
1969 if context.config.spaces_within_parens_and_brackets() && !fd.inputs.is_empty() {
1972 // If the last line of args contains comment, we cannot put the closing paren
1973 // on the same line.
1977 .map_or(false, |last_line| last_line.contains("//"))
1979 args_last_line_contains_comment = true;
1980 result.push_str(&arg_indent.to_string_with_newline(context.config));
1986 if let ast::FunctionRetTy::Ty(..) = fd.output {
1987 let ret_should_indent = match context.config.indent_style() {
1988 // If our args are block layout then we surely must have space.
1989 IndentStyle::Block if put_args_in_block || fd.inputs.is_empty() => false,
1990 _ if args_last_line_contains_comment => false,
1991 _ if result.contains('\n') || multi_line_ret_str => true,
1993 // If the return type would push over the max width, then put the return type on
1994 // a new line. With the +1 for the signature length an additional space between
1995 // the closing parenthesis of the argument and the arrow '->' is considered.
1996 let mut sig_length = result.len() + indent.width() + ret_str_len + 1;
1998 // If there is no where clause, take into account the space after the return type
2000 if where_clause.predicates.is_empty() {
2004 sig_length > context.config.max_width()
2007 let ret_indent = if ret_should_indent {
2008 let indent = if arg_str.is_empty() {
2009 // Aligning with non-existent args looks silly.
2010 force_new_line_for_brace = true;
2013 // FIXME: we might want to check that using the arg indent
2014 // doesn't blow our budget, and if it does, then fallback to
2015 // the where clause indent.
2019 result.push_str(&indent.to_string_with_newline(context.config));
2023 Indent::new(indent.block_indent, last_line_width(&result))
2026 if multi_line_ret_str || ret_should_indent {
2027 // Now that we know the proper indent and width, we need to
2028 // re-layout the return type.
2029 let ret_str = fd.output
2030 .rewrite(context, Shape::indented(ret_indent, context.config))?;
2031 result.push_str(&ret_str);
2033 result.push_str(&ret_str);
2036 // Comment between return type and the end of the decl.
2037 let snippet_lo = fd.output.span().hi();
2038 if where_clause.predicates.is_empty() {
2039 let snippet_hi = span.hi();
2040 let snippet = context.snippet(mk_sp(snippet_lo, snippet_hi));
2041 // Try to preserve the layout of the original snippet.
2042 let original_starts_with_newline = snippet
2044 .map_or(false, |i| starts_with_newline(&snippet[i..]));
2045 let original_ends_with_newline = snippet
2046 .rfind(|c| c != ' ')
2047 .map_or(false, |i| snippet[i..].ends_with('\n'));
2048 let snippet = snippet.trim();
2049 if !snippet.is_empty() {
2050 result.push(if original_starts_with_newline {
2055 result.push_str(snippet);
2056 if original_ends_with_newline {
2057 force_new_line_for_brace = true;
2063 let pos_before_where = match fd.output {
2064 ast::FunctionRetTy::Default(..) => args_span.hi(),
2065 ast::FunctionRetTy::Ty(ref ty) => ty.span.hi(),
2068 let is_args_multi_lined = arg_str.contains('\n');
2070 let option = WhereClauseOption::new(!has_body, put_args_in_block && ret_str.is_empty());
2071 let where_clause_str = rewrite_where_clause(
2074 context.config.brace_style(),
2075 Shape::indented(indent, context.config),
2081 is_args_multi_lined,
2083 // If there are neither where clause nor return type, we may be missing comments between
2085 if where_clause_str.is_empty() {
2086 if let ast::FunctionRetTy::Default(ret_span) = fd.output {
2087 match recover_missing_comment_in_span(
2088 mk_sp(args_span.hi(), ret_span.hi()),
2091 last_line_width(&result),
2093 Some(ref missing_comment) if !missing_comment.is_empty() => {
2094 result.push_str(missing_comment);
2095 force_new_line_for_brace = true;
2102 result.push_str(&where_clause_str);
2104 force_new_line_for_brace |= last_line_contains_single_line_comment(&result);
2105 force_new_line_for_brace |= is_args_multi_lined && context.config.where_single_line();
2106 Some((result, force_new_line_for_brace))
2109 #[derive(Copy, Clone)]
2110 struct WhereClauseOption {
2111 suppress_comma: bool, // Force no trailing comma
2112 snuggle: bool, // Do not insert newline before `where`
2113 compress_where: bool, // Try single line where clause instead of vertical layout
2116 impl WhereClauseOption {
2117 pub fn new(suppress_comma: bool, snuggle: bool) -> WhereClauseOption {
2121 compress_where: false,
2125 pub fn snuggled(current: &str) -> WhereClauseOption {
2127 suppress_comma: false,
2128 snuggle: trimmed_last_line_width(current) == 1,
2129 compress_where: false,
2135 context: &RewriteContext,
2137 explicit_self: Option<&ast::ExplicitSelf>,
2138 one_line_budget: usize,
2139 multi_line_budget: usize,
2144 generics_str_contains_newline: bool,
2145 ) -> Option<String> {
2146 let mut arg_item_strs = args.iter()
2147 .map(|arg| arg.rewrite(context, Shape::legacy(multi_line_budget, arg_indent)))
2148 .collect::<Option<Vec<_>>>()?;
2150 // Account for sugary self.
2151 // FIXME: the comment for the self argument is dropped. This is blocked
2152 // on rust issue #27522.
2153 let min_args = explicit_self
2154 .and_then(|explicit_self| rewrite_explicit_self(explicit_self, args, context))
2155 .map_or(1, |self_str| {
2156 arg_item_strs[0] = self_str;
2160 // Comments between args.
2161 let mut arg_items = Vec::new();
2163 arg_items.push(ListItem::from_str(""));
2166 // FIXME(#21): if there are no args, there might still be a comment, but
2167 // without spans for the comment or parens, there is no chance of
2168 // getting it right. You also don't get to put a comment on self, unless
2170 if args.len() >= min_args || variadic {
2171 let comment_span_start = if min_args == 2 {
2172 let second_arg_start = if arg_has_pattern(&args[1]) {
2173 args[1].pat.span.lo()
2175 args[1].ty.span.lo()
2177 let reduced_span = mk_sp(span.lo(), second_arg_start);
2179 context.snippet_provider.span_after_last(reduced_span, ",")
2184 enum ArgumentKind<'a> {
2185 Regular(&'a ast::Arg),
2189 let variadic_arg = if variadic {
2190 let variadic_span = mk_sp(args.last().unwrap().ty.span.hi(), span.hi());
2191 let variadic_start =
2192 context.snippet_provider.span_after(variadic_span, "...") - BytePos(3);
2193 Some(ArgumentKind::Variadic(variadic_start))
2198 let more_items = itemize_list(
2199 context.snippet_provider,
2200 args[min_args - 1..]
2202 .map(ArgumentKind::Regular)
2203 .chain(variadic_arg),
2207 ArgumentKind::Regular(arg) => span_lo_for_arg(arg),
2208 ArgumentKind::Variadic(start) => start,
2211 ArgumentKind::Regular(arg) => arg.ty.span.hi(),
2212 ArgumentKind::Variadic(start) => start + BytePos(3),
2215 ArgumentKind::Regular(..) => None,
2216 ArgumentKind::Variadic(..) => Some("...".to_owned()),
2223 arg_items.extend(more_items);
2226 let fits_in_one_line = !generics_str_contains_newline
2227 && (arg_items.is_empty()
2228 || arg_items.len() == 1 && arg_item_strs[0].len() <= one_line_budget);
2230 for (item, arg) in arg_items.iter_mut().zip(arg_item_strs) {
2231 item.item = Some(arg);
2234 let last_line_ends_with_comment = arg_items
2237 .and_then(|item| item.post_comment.as_ref())
2238 .map_or(false, |s| s.trim().starts_with("//"));
2240 let (indent, trailing_comma) = match context.config.indent_style() {
2241 IndentStyle::Block if fits_in_one_line => {
2242 (indent.block_indent(context.config), SeparatorTactic::Never)
2244 IndentStyle::Block => (
2245 indent.block_indent(context.config),
2246 context.config.trailing_comma(),
2248 IndentStyle::Visual if last_line_ends_with_comment => {
2249 (arg_indent, context.config.trailing_comma())
2251 IndentStyle::Visual => (arg_indent, SeparatorTactic::Never),
2254 let tactic = definitive_tactic(
2256 context.config.fn_args_density().to_list_tactic(),
2260 let budget = match tactic {
2261 DefinitiveListTactic::Horizontal => one_line_budget,
2262 _ => multi_line_budget,
2265 debug!("rewrite_args: budget: {}, tactic: {:?}", budget, tactic);
2267 let fmt = ListFormatting {
2270 trailing_separator: if variadic {
2271 SeparatorTactic::Never
2275 separator_place: SeparatorPlace::Back,
2276 shape: Shape::legacy(budget, indent),
2277 ends_with_newline: tactic.ends_with_newline(context.config.indent_style()),
2278 preserve_newline: true,
2279 config: context.config,
2282 write_list(&arg_items, &fmt)
2285 fn arg_has_pattern(arg: &ast::Arg) -> bool {
2286 if let ast::PatKind::Ident(_, ident, _) = arg.pat.node {
2287 ident != symbol::keywords::Invalid.ident()
2293 fn compute_budgets_for_args(
2294 context: &RewriteContext,
2298 newline_brace: bool,
2300 force_vertical_layout: bool,
2301 ) -> Option<((usize, usize, Indent))> {
2303 "compute_budgets_for_args {} {:?}, {}, {}",
2309 // Try keeping everything on the same line.
2310 if !result.contains('\n') && !force_vertical_layout {
2311 // 2 = `()`, 3 = `() `, space is before ret_string.
2312 let overhead = if ret_str_len == 0 { 2 } else { 3 };
2313 let mut used_space = indent.width() + result.len() + ret_str_len + overhead;
2323 let one_line_budget = context.budget(used_space);
2325 if one_line_budget > 0 {
2327 let (indent, multi_line_budget) = match context.config.indent_style() {
2328 IndentStyle::Block => {
2329 let indent = indent.block_indent(context.config);
2330 (indent, context.budget(indent.width() + 1))
2332 IndentStyle::Visual => {
2333 let indent = indent + result.len() + 1;
2334 let multi_line_overhead = indent.width() + if newline_brace { 2 } else { 4 };
2335 (indent, context.budget(multi_line_overhead))
2339 return Some((one_line_budget, multi_line_budget, indent));
2343 // Didn't work. we must force vertical layout and put args on a newline.
2344 let new_indent = indent.block_indent(context.config);
2345 let used_space = match context.config.indent_style() {
2347 IndentStyle::Block => new_indent.width() + 1,
2348 // Account for `)` and possibly ` {`.
2349 IndentStyle::Visual => new_indent.width() + if ret_str_len == 0 { 1 } else { 3 },
2351 Some((0, context.budget(used_space), new_indent))
2354 fn newline_for_brace(config: &Config, where_clause: &ast::WhereClause) -> bool {
2355 let predicate_count = where_clause.predicates.len();
2357 if config.where_single_line() && predicate_count == 1 {
2360 let brace_style = config.brace_style();
2362 brace_style == BraceStyle::AlwaysNextLine
2363 || (brace_style == BraceStyle::SameLineWhere && predicate_count > 0)
2366 fn rewrite_generics(
2367 context: &RewriteContext,
2369 generics: &ast::Generics,
2372 ) -> Option<String> {
2373 // FIXME: convert bounds to where clauses where they get too big or if
2374 // there is a where clause at all.
2376 if generics.params.is_empty() {
2377 return Some(ident.to_owned());
2380 let params = &generics.params.iter().map(|e| &*e).collect::<Vec<_>>();
2381 overflow::rewrite_with_angle_brackets(context, ident, params, shape, span)
2384 pub fn generics_shape_from_config(config: &Config, shape: Shape, offset: usize) -> Option<Shape> {
2385 match config.indent_style() {
2386 IndentStyle::Visual => shape.visual_indent(1 + offset).sub_width(offset + 2),
2387 IndentStyle::Block => {
2391 .block_indent(config.tab_spaces())
2392 .with_max_width(config)
2398 fn rewrite_where_clause_rfc_style(
2399 context: &RewriteContext,
2400 where_clause: &ast::WhereClause,
2403 span_end: Option<BytePos>,
2404 span_end_before_where: BytePos,
2405 where_clause_option: WhereClauseOption,
2406 is_args_multi_line: bool,
2407 ) -> Option<String> {
2408 let block_shape = shape.block().with_max_width(context.config);
2410 let (span_before, span_after) =
2411 missing_span_before_after_where(span_end_before_where, where_clause);
2412 let (comment_before, comment_after) =
2413 rewrite_comments_before_after_where(context, span_before, span_after, shape)?;
2415 let starting_newline = if where_clause_option.snuggle && comment_before.is_empty() {
2418 block_shape.indent.to_string_with_newline(context.config)
2421 let clause_shape = block_shape.block_left(context.config.tab_spaces())?;
2423 let clause_shape = clause_shape.sub_width(1)?;
2424 // each clause on one line, trailing comma (except if suppress_comma)
2425 let span_start = where_clause.predicates[0].span().lo();
2426 // If we don't have the start of the next span, then use the end of the
2427 // predicates, but that means we miss comments.
2428 let len = where_clause.predicates.len();
2429 let end_of_preds = where_clause.predicates[len - 1].span().hi();
2430 let span_end = span_end.unwrap_or(end_of_preds);
2431 let items = itemize_list(
2432 context.snippet_provider,
2433 where_clause.predicates.iter(),
2436 |pred| pred.span().lo(),
2437 |pred| pred.span().hi(),
2438 |pred| pred.rewrite(context, clause_shape),
2443 let where_single_line = context.config.where_single_line() && len == 1 && !is_args_multi_line;
2444 let comma_tactic = if where_clause_option.suppress_comma || where_single_line {
2445 SeparatorTactic::Never
2447 context.config.trailing_comma()
2450 // shape should be vertical only and only if we have `where_single_line` option enabled
2451 // and the number of items of the where clause is equal to 1
2452 let shape_tactic = if where_single_line {
2453 DefinitiveListTactic::Horizontal
2455 DefinitiveListTactic::Vertical
2458 let fmt = ListFormatting {
2459 tactic: shape_tactic,
2461 trailing_separator: comma_tactic,
2462 separator_place: SeparatorPlace::Back,
2463 shape: clause_shape,
2464 ends_with_newline: true,
2465 preserve_newline: true,
2466 config: context.config,
2468 let preds_str = write_list(&items.collect::<Vec<_>>(), &fmt)?;
2470 let comment_separator = |comment: &str, shape: Shape| {
2471 if comment.is_empty() {
2474 shape.indent.to_string_with_newline(context.config)
2477 let newline_before_where = comment_separator(&comment_before, shape);
2478 let newline_after_where = comment_separator(&comment_after, clause_shape);
2481 let clause_sep = if where_clause_option.compress_where && comment_before.is_empty()
2482 && comment_after.is_empty() && !preds_str.contains('\n')
2483 && 6 + preds_str.len() <= shape.width || where_single_line
2487 clause_shape.indent.to_string_with_newline(context.config)
2490 "{}{}{}where{}{}{}{}",
2493 newline_before_where,
2494 newline_after_where,
2501 fn rewrite_where_clause(
2502 context: &RewriteContext,
2503 where_clause: &ast::WhereClause,
2504 brace_style: BraceStyle,
2508 span_end: Option<BytePos>,
2509 span_end_before_where: BytePos,
2510 where_clause_option: WhereClauseOption,
2511 is_args_multi_line: bool,
2512 ) -> Option<String> {
2513 if where_clause.predicates.is_empty() {
2514 return Some(String::new());
2517 if context.config.indent_style() == IndentStyle::Block {
2518 return rewrite_where_clause_rfc_style(
2524 span_end_before_where,
2525 where_clause_option,
2530 let extra_indent = Indent::new(context.config.tab_spaces(), 0);
2532 let offset = match context.config.indent_style() {
2533 IndentStyle::Block => shape.indent + extra_indent.block_indent(context.config),
2534 // 6 = "where ".len()
2535 IndentStyle::Visual => shape.indent + extra_indent + 6,
2537 // FIXME: if indent_style != Visual, then the budgets below might
2538 // be out by a char or two.
2540 let budget = context.config.max_width() - offset.width();
2541 let span_start = where_clause.predicates[0].span().lo();
2542 // If we don't have the start of the next span, then use the end of the
2543 // predicates, but that means we miss comments.
2544 let len = where_clause.predicates.len();
2545 let end_of_preds = where_clause.predicates[len - 1].span().hi();
2546 let span_end = span_end.unwrap_or(end_of_preds);
2547 let items = itemize_list(
2548 context.snippet_provider,
2549 where_clause.predicates.iter(),
2552 |pred| pred.span().lo(),
2553 |pred| pred.span().hi(),
2554 |pred| pred.rewrite(context, Shape::legacy(budget, offset)),
2559 let item_vec = items.collect::<Vec<_>>();
2560 // FIXME: we don't need to collect here
2561 let tactic = definitive_tactic(&item_vec, ListTactic::Vertical, Separator::Comma, budget);
2563 let mut comma_tactic = context.config.trailing_comma();
2564 // Kind of a hack because we don't usually have trailing commas in where clauses.
2565 if comma_tactic == SeparatorTactic::Vertical || where_clause_option.suppress_comma {
2566 comma_tactic = SeparatorTactic::Never;
2569 let fmt = ListFormatting {
2572 trailing_separator: comma_tactic,
2573 separator_place: SeparatorPlace::Back,
2574 shape: Shape::legacy(budget, offset),
2575 ends_with_newline: tactic.ends_with_newline(context.config.indent_style()),
2576 preserve_newline: true,
2577 config: context.config,
2579 let preds_str = write_list(&item_vec, &fmt)?;
2581 let end_length = if terminator == "{" {
2582 // If the brace is on the next line we don't need to count it otherwise it needs two
2585 BraceStyle::AlwaysNextLine | BraceStyle::SameLineWhere => 0,
2586 BraceStyle::PreferSameLine => 2,
2588 } else if terminator == "=" {
2593 if density == Density::Tall || preds_str.contains('\n')
2594 || shape.indent.width() + " where ".len() + preds_str.len() + end_length > shape.width
2598 (shape.indent + extra_indent).to_string(context.config),
2602 Some(format!(" where {}", preds_str))
2606 fn missing_span_before_after_where(
2607 before_item_span_end: BytePos,
2608 where_clause: &ast::WhereClause,
2610 let missing_span_before = mk_sp(before_item_span_end, where_clause.span.lo());
2612 let pos_after_where = where_clause.span.lo() + BytePos(5);
2613 let missing_span_after = mk_sp(pos_after_where, where_clause.predicates[0].span().lo());
2614 (missing_span_before, missing_span_after)
2617 fn rewrite_comments_before_after_where(
2618 context: &RewriteContext,
2619 span_before_where: Span,
2620 span_after_where: Span,
2622 ) -> Option<(String, String)> {
2623 let before_comment = rewrite_missing_comment(span_before_where, shape, context)?;
2624 let after_comment = rewrite_missing_comment(
2626 shape.block_indent(context.config.tab_spaces()),
2629 Some((before_comment, after_comment))
2632 fn format_header(item_name: &str, ident: ast::Ident, vis: &ast::Visibility) -> String {
2633 format!("{}{}{}", format_visibility(vis), item_name, ident)
2636 #[derive(PartialEq, Eq, Clone, Copy)]
2644 context: &RewriteContext,
2645 generics: &ast::Generics,
2646 brace_style: BraceStyle,
2647 brace_pos: BracePos,
2651 ) -> Option<String> {
2652 let shape = Shape::legacy(context.budget(used_width + offset.width()), offset);
2653 let mut result = rewrite_generics(context, "", generics, shape, span)?;
2655 let same_line_brace = if !generics.where_clause.predicates.is_empty() || result.contains('\n') {
2656 let budget = context.budget(last_line_used_width(&result, offset.width()));
2657 let mut option = WhereClauseOption::snuggled(&result);
2658 if brace_pos == BracePos::None {
2659 option.suppress_comma = true;
2661 // If the generics are not parameterized then generics.span.hi() == 0,
2662 // so we use span.lo(), which is the position after `struct Foo`.
2663 let span_end_before_where = if generics.is_parameterized() {
2668 let where_clause_str = rewrite_where_clause(
2670 &generics.where_clause,
2672 Shape::legacy(budget, offset.block_only()),
2676 span_end_before_where,
2680 result.push_str(&where_clause_str);
2681 brace_pos == BracePos::ForceSameLine || brace_style == BraceStyle::PreferSameLine
2682 || (generics.where_clause.predicates.is_empty()
2683 && trimmed_last_line_width(&result) == 1)
2685 brace_pos == BracePos::ForceSameLine || trimmed_last_line_width(&result) == 1
2686 || brace_style != BraceStyle::AlwaysNextLine
2688 if brace_pos == BracePos::None {
2689 return Some(result);
2691 let total_used_width = last_line_used_width(&result, used_width);
2692 let remaining_budget = context.budget(total_used_width);
2693 // If the same line brace if forced, it indicates that we are rewriting an item with empty body,
2694 // and hence we take the closer into account as well for one line budget.
2695 // We assume that the closer has the same length as the opener.
2696 let overhead = if brace_pos == BracePos::ForceSameLine {
2703 let forbid_same_line_brace = overhead > remaining_budget;
2704 if !forbid_same_line_brace && same_line_brace {
2708 result.push_str(&offset.block_only().to_string(context.config));
2715 impl Rewrite for ast::ForeignItem {
2716 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
2717 let attrs_str = self.attrs.rewrite(context, shape)?;
2718 // Drop semicolon or it will be interpreted as comment.
2719 // FIXME: this may be a faulty span from libsyntax.
2720 let span = mk_sp(self.span.lo(), self.span.hi() - BytePos(1));
2722 let item_str = match self.node {
2723 ast::ForeignItemKind::Fn(ref fn_decl, ref generics) => {
2728 &FnSig::new(fn_decl, generics, self.vis.clone()),
2732 ).map(|(s, _)| format!("{};", s))
2734 ast::ForeignItemKind::Static(ref ty, is_mutable) => {
2735 // FIXME(#21): we're dropping potential comments in between the
2736 // function keywords here.
2737 let vis = format_visibility(&self.vis);
2738 let mut_str = if is_mutable { "mut " } else { "" };
2739 let prefix = format!("{}static {}{}:", vis, mut_str, self.ident);
2741 rewrite_assign_rhs(context, prefix, &**ty, shape.sub_width(1)?).map(|s| s + ";")
2743 ast::ForeignItemKind::Ty => {
2744 let vis = format_visibility(&self.vis);
2745 Some(format!("{}type {};", vis, self.ident))
2747 ast::ForeignItemKind::Macro(ref mac) => {
2748 rewrite_macro(mac, None, context, shape, MacroPosition::Item)
2752 let missing_span = if self.attrs.is_empty() {
2753 mk_sp(self.span.lo(), self.span.lo())
2755 mk_sp(self.attrs[self.attrs.len() - 1].span.hi(), self.span.lo())
2757 combine_strs_with_missing_comments(
2768 impl Rewrite for ast::GenericParam {
2769 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
2771 ast::GenericParam::Lifetime(ref lifetime_def) => lifetime_def.rewrite(context, shape),
2772 ast::GenericParam::Type(ref ty) => ty.rewrite(context, shape),
2777 /// Rewrite an inline mod.
2778 pub fn rewrite_mod(item: &ast::Item) -> String {
2779 let mut result = String::with_capacity(32);
2780 result.push_str(&*format_visibility(&item.vis));
2781 result.push_str("mod ");
2782 result.push_str(&item.ident.to_string());
2787 /// Rewrite `extern crate foo;` WITHOUT attributes.
2788 pub fn rewrite_extern_crate(context: &RewriteContext, item: &ast::Item) -> Option<String> {
2789 assert!(is_extern_crate(item));
2790 let new_str = context.snippet(item.span);
2791 Some(if contains_comment(new_str) {
2794 let no_whitespace = &new_str.split_whitespace().collect::<Vec<&str>>().join(" ");
2795 String::from(&*Regex::new(r"\s;").unwrap().replace(no_whitespace, ";"))
2799 /// Returns true for `mod foo;`, false for `mod foo { .. }`.
2800 pub fn is_mod_decl(item: &ast::Item) -> bool {
2802 ast::ItemKind::Mod(ref m) => m.inner.hi() != item.span.hi(),
2807 pub fn is_use_item(item: &ast::Item) -> bool {
2809 ast::ItemKind::Use(_) => true,
2814 pub fn is_extern_crate(item: &ast::Item) -> bool {
2816 ast::ItemKind::ExternCrate(..) => true,