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
317 || force_newline_brace
318 || last_line_width(&result) + 2 > self.shape().width
320 newline_brace = true;
321 } else if !result.contains('\n') {
322 newline_brace = false;
325 // Prepare for the function body by possibly adding a newline and
327 // FIXME we'll miss anything between the end of the signature and the
328 // start of the body, but we need more spans from the compiler to solve
331 result.push_str(&indent.to_string_with_newline(self.config));
336 self.single_line_fn(&result, block, inner_attrs)
337 .or_else(|| Some(result))
340 pub fn rewrite_required_fn(
344 sig: &ast::MethodSig,
345 generics: &ast::Generics,
347 ) -> Option<String> {
348 // Drop semicolon or it will be interpreted as comment.
349 let span = mk_sp(span.lo(), span.hi() - BytePos(1));
350 let context = self.get_context();
352 let (mut result, _) = rewrite_fn_base(
356 &FnSig::from_method_sig(sig, generics),
362 // Re-attach semicolon
372 inner_attrs: Option<&[ast::Attribute]>,
373 ) -> Option<String> {
374 if fn_str.contains('\n') || inner_attrs.map_or(false, |a| !a.is_empty()) {
378 let codemap = self.get_context().codemap;
380 if self.config.empty_item_single_line()
381 && is_empty_block(block, None, codemap)
382 && self.block_indent.width() + fn_str.len() + 2 <= self.config.max_width()
384 return Some(format!("{}{{}}", fn_str));
387 if self.config.fn_single_line() && is_simple_block_stmt(block, None, codemap) {
389 if let Some(stmt) = block.stmts.first() {
390 match stmt_expr(stmt) {
392 let suffix = if semicolon_for_expr(&self.get_context(), e) {
398 format_expr(e, ExprType::Statement, &self.get_context(), self.shape())
400 .or_else(|| Some(self.snippet(e.span).to_owned()))
402 None => stmt.rewrite(&self.get_context(), self.shape()),
409 if let Some(res) = rewrite {
410 let width = self.block_indent.width() + fn_str.len() + res.len() + 4;
411 if !res.contains('\n') && width <= self.config.max_width() {
412 return Some(format!("{}{{ {} }}", fn_str, res));
420 pub fn visit_static(&mut self, static_parts: &StaticParts) {
421 let rewrite = rewrite_static(&self.get_context(), static_parts, self.block_indent);
422 self.push_rewrite(static_parts.span, rewrite);
425 pub fn visit_struct(&mut self, struct_parts: &StructParts) {
426 let is_tuple = struct_parts.def.is_tuple();
427 let rewrite = format_struct(&self.get_context(), struct_parts, self.block_indent, None)
428 .map(|s| if is_tuple { s + ";" } else { s });
429 self.push_rewrite(struct_parts.span, rewrite);
435 vis: &ast::Visibility,
436 enum_def: &ast::EnumDef,
437 generics: &ast::Generics,
440 let enum_header = format_header("enum ", ident, vis);
441 self.push_str(&enum_header);
443 let enum_snippet = self.snippet(span);
444 let brace_pos = enum_snippet.find_uncommented("{").unwrap();
445 let body_start = span.lo() + BytePos(brace_pos as u32 + 1);
446 let generics_str = format_generics(
449 self.config.brace_style(),
450 if enum_def.variants.is_empty() {
451 BracePos::ForceSameLine
456 mk_sp(span.lo(), body_start),
457 last_line_width(&enum_header),
459 self.push_str(&generics_str);
461 self.last_pos = body_start;
463 match self.format_variant_list(enum_def, body_start, span.hi()) {
464 Some(ref s) if enum_def.variants.is_empty() => self.push_str(s),
466 self.push_rewrite(mk_sp(body_start, span.hi()), rw);
467 self.block_indent = self.block_indent.block_unindent(self.config);
472 // Format the body of an enum definition
473 fn format_variant_list(
475 enum_def: &ast::EnumDef,
478 ) -> Option<String> {
479 if enum_def.variants.is_empty() {
480 let mut buffer = String::with_capacity(128);
482 let span = mk_sp(body_lo, body_hi - BytePos(1));
483 format_empty_struct_or_tuple(
493 let mut result = String::with_capacity(1024);
494 let original_offset = self.block_indent;
495 self.block_indent = self.block_indent.block_indent(self.config);
497 let itemize_list_with = |one_line_width: usize| {
499 self.snippet_provider,
500 enum_def.variants.iter(),
504 if !f.node.attrs.is_empty() {
505 f.node.attrs[0].span.lo()
511 |f| self.format_variant(f, one_line_width),
517 let mut items: Vec<_> =
518 itemize_list_with(self.config.width_heuristics().struct_variant_width);
519 // If one of the variants use multiple lines, use multi-lined formatting for all variants.
520 let has_multiline_variant = items.iter().any(|item| item.inner_as_ref().contains('\n'));
521 let has_single_line_variant = items.iter().any(|item| !item.inner_as_ref().contains('\n'));
522 if has_multiline_variant && has_single_line_variant {
523 items = itemize_list_with(0);
526 let shape = self.shape().sub_width(2)?;
527 let fmt = ListFormatting {
528 tactic: DefinitiveListTactic::Vertical,
530 trailing_separator: self.config.trailing_comma(),
531 separator_place: SeparatorPlace::Back,
533 ends_with_newline: true,
534 preserve_newline: true,
538 let list = write_list(&items, &fmt)?;
539 result.push_str(&list);
540 result.push_str(&original_offset.to_string_with_newline(self.config));
545 // Variant of an enum.
546 fn format_variant(&self, field: &ast::Variant, one_line_width: usize) -> Option<String> {
547 if contains_skip(&field.node.attrs) {
548 let lo = field.node.attrs[0].span.lo();
549 let span = mk_sp(lo, field.span.hi());
550 return Some(self.snippet(span).to_owned());
553 let context = self.get_context();
555 let shape = self.shape().sub_width(1)?;
556 let attrs_str = field.node.attrs.rewrite(&context, shape)?;
561 .map_or(field.span.lo(), |attr| attr.span.hi());
562 let span = mk_sp(lo, field.span.lo());
564 let variant_body = match field.node.data {
565 ast::VariantData::Tuple(..) | ast::VariantData::Struct(..) => format_struct(
567 &StructParts::from_variant(field),
569 Some(one_line_width),
571 ast::VariantData::Unit(..) => {
572 if let Some(ref expr) = field.node.disr_expr {
573 let lhs = format!("{} =", field.node.ident.name);
574 rewrite_assign_rhs(&context, lhs, &**expr, shape)?
576 field.node.ident.name.to_string()
581 combine_strs_with_missing_comments(&context, &attrs_str, &variant_body, span, shape, false)
584 fn visit_impl_items(&mut self, items: &[ast::ImplItem]) {
585 if self.get_context().config.reorder_impl_items() {
586 // Create visitor for each items, then reorder them.
587 let mut buffer = vec![];
589 self.visit_impl_item(item);
590 buffer.push((self.buffer.clone(), item.clone()));
593 // type -> const -> macro -> method
594 use ast::ImplItemKind::*;
595 fn need_empty_line(a: &ast::ImplItemKind, b: &ast::ImplItemKind) -> bool {
597 (Type(..), Type(..)) | (Const(..), Const(..)) => false,
602 buffer.sort_by(|(_, a), (_, b)| match (&a.node, &b.node) {
603 (Type(..), _) => Ordering::Less,
604 (_, Type(..)) => Ordering::Greater,
605 (Const(..), _) => Ordering::Less,
606 (_, Const(..)) => Ordering::Greater,
607 (Macro(..), _) => Ordering::Less,
608 (_, Macro(..)) => Ordering::Greater,
609 _ => a.span.lo().cmp(&b.span.lo()),
611 let mut prev_kind = None;
612 for (buf, item) in buffer {
613 // Make sure that there are at least a single empty line between
614 // different impl items.
617 .map_or(false, |prev_kind| need_empty_line(prev_kind, &item.node))
621 let indent_str = self.block_indent.to_string_with_newline(self.config);
622 self.push_str(&indent_str);
623 self.push_str(buf.trim());
624 prev_kind = Some(item.node.clone());
628 self.visit_impl_item(item);
635 context: &RewriteContext,
638 where_span_end: Option<BytePos>,
639 ) -> Option<String> {
640 if let ast::ItemKind::Impl(_, _, _, ref generics, _, ref self_ty, ref items) = item.node {
641 let mut result = String::with_capacity(128);
642 let ref_and_type = format_impl_ref_and_type(context, item, offset)?;
643 let sep = offset.to_string_with_newline(context.config);
644 result.push_str(&ref_and_type);
646 let where_budget = if result.contains('\n') {
647 context.config.max_width()
649 context.budget(last_line_width(&result))
651 let option = WhereClauseOption::snuggled(&ref_and_type);
652 let where_clause_str = rewrite_where_clause(
654 &generics.where_clause,
655 context.config.brace_style(),
656 Shape::legacy(where_budget, offset.block_only()),
665 // If there is no where clause, we may have missing comments between the trait name and
666 // the opening brace.
667 if generics.where_clause.predicates.is_empty() {
668 if let Some(hi) = where_span_end {
669 match recover_missing_comment_in_span(
670 mk_sp(self_ty.span.hi(), hi),
671 Shape::indented(offset, context.config),
673 last_line_width(&result),
675 Some(ref missing_comment) if !missing_comment.is_empty() => {
676 result.push_str(missing_comment);
683 if is_impl_single_line(context, items, &result, &where_clause_str, item)? {
684 result.push_str(&where_clause_str);
685 if where_clause_str.contains('\n') || last_line_contains_single_line_comment(&result) {
686 result.push_str(&format!("{}{{{}}}", &sep, &sep));
688 result.push_str(" {}");
693 if !where_clause_str.is_empty() && !where_clause_str.contains('\n') {
694 let width = offset.block_indent + context.config.tab_spaces() - 1;
695 let where_indent = Indent::new(0, width);
696 result.push_str(&where_indent.to_string_with_newline(context.config));
698 result.push_str(&where_clause_str);
700 let need_newline = last_line_contains_single_line_comment(&result) || result.contains('\n');
701 match context.config.brace_style() {
702 _ if need_newline => result.push_str(&sep),
703 BraceStyle::AlwaysNextLine => result.push_str(&sep),
704 BraceStyle::PreferSameLine => result.push(' '),
705 BraceStyle::SameLineWhere => {
706 if !where_clause_str.is_empty() {
707 result.push_str(&sep);
716 let snippet = context.snippet(item.span);
717 let open_pos = snippet.find_uncommented("{")? + 1;
719 if !items.is_empty() || contains_comment(&snippet[open_pos..]) {
720 let mut visitor = FmtVisitor::from_context(context);
721 let item_indent = offset.block_only().block_indent(context.config);
722 visitor.block_indent = item_indent;
723 visitor.last_pos = item.span.lo() + BytePos(open_pos as u32);
725 visitor.visit_attrs(&item.attrs, ast::AttrStyle::Inner);
726 visitor.visit_impl_items(items);
728 visitor.format_missing(item.span.hi() - BytePos(1));
730 let inner_indent_str = visitor.block_indent.to_string_with_newline(context.config);
731 let outer_indent_str = offset.block_only().to_string_with_newline(context.config);
733 result.push_str(&inner_indent_str);
734 result.push_str(visitor.buffer.to_string().trim());
735 result.push_str(&outer_indent_str);
738 if result.ends_with('{') {
739 result.push_str(&sep);
749 fn is_impl_single_line(
750 context: &RewriteContext,
751 items: &[ast::ImplItem],
753 where_clause_str: &str,
756 let snippet = context.snippet(item.span);
757 let open_pos = snippet.find_uncommented("{")? + 1;
760 context.config.empty_item_single_line()
762 && !result.contains('\n')
763 && result.len() + where_clause_str.len() <= context.config.max_width()
764 && !contains_comment(&snippet[open_pos..]),
768 fn format_impl_ref_and_type(
769 context: &RewriteContext,
772 ) -> Option<String> {
773 if let ast::ItemKind::Impl(
783 let mut result = String::with_capacity(128);
785 result.push_str(&format_visibility(&item.vis));
786 result.push_str(format_defaultness(defaultness));
787 result.push_str(format_unsafety(unsafety));
789 let lo = context.snippet_provider.span_after(item.span, "impl");
790 let hi = match *trait_ref {
791 Some(ref tr) => tr.path.span.lo(),
792 None => self_ty.span.lo(),
794 let shape = generics_shape_from_config(
796 Shape::indented(offset + last_line_width(&result), context.config),
799 let generics_str = rewrite_generics(context, "impl", generics, shape, mk_sp(lo, hi))?;
800 result.push_str(&generics_str);
802 let polarity_str = if polarity == ast::ImplPolarity::Negative {
808 if let Some(ref trait_ref) = *trait_ref {
809 let result_len = last_line_width(&result);
810 result.push_str(&rewrite_trait_ref(
819 // Try to put the self type in a single line.
821 let trait_ref_overhead = if trait_ref.is_some() { 4 } else { 0 };
822 let curly_brace_overhead = if generics.where_clause.predicates.is_empty() {
823 // If there is no where clause adapt budget for type formatting to take space and curly
824 // brace into account.
825 match context.config.brace_style() {
826 BraceStyle::AlwaysNextLine => 0,
832 let used_space = last_line_width(&result) + trait_ref_overhead + curly_brace_overhead;
833 // 1 = space before the type.
834 let budget = context.budget(used_space + 1);
835 if let Some(self_ty_str) = self_ty.rewrite(context, Shape::legacy(budget, offset)) {
836 if !self_ty_str.contains('\n') {
837 if trait_ref.is_some() {
838 result.push_str(" for ");
842 result.push_str(&self_ty_str);
847 // Couldn't fit the self type on a single line, put it on a new line.
849 // Add indentation of one additional tab.
850 let new_line_offset = offset.block_indent(context.config);
851 result.push_str(&new_line_offset.to_string(context.config));
852 if trait_ref.is_some() {
853 result.push_str("for ");
855 let budget = context.budget(last_line_width(&result));
856 let type_offset = match context.config.indent_style() {
857 IndentStyle::Visual => new_line_offset + trait_ref_overhead,
858 IndentStyle::Block => new_line_offset,
860 result.push_str(&*self_ty.rewrite(context, Shape::legacy(budget, type_offset))?);
867 fn rewrite_trait_ref(
868 context: &RewriteContext,
869 trait_ref: &ast::TraitRef,
873 ) -> Option<String> {
874 // 1 = space between generics and trait_ref
875 let used_space = 1 + polarity_str.len() + result_len;
876 let shape = Shape::indented(offset + used_space, context.config);
877 if let Some(trait_ref_str) = trait_ref.rewrite(context, shape) {
878 if !trait_ref_str.contains('\n') {
879 return Some(format!(" {}{}", polarity_str, &trait_ref_str));
882 // We could not make enough space for trait_ref, so put it on new line.
883 let offset = offset.block_indent(context.config);
884 let shape = Shape::indented(offset, context.config);
885 let trait_ref_str = trait_ref.rewrite(context, shape)?;
888 &offset.to_string_with_newline(context.config),
894 pub struct StructParts<'a> {
897 vis: &'a ast::Visibility,
898 def: &'a ast::VariantData,
899 generics: Option<&'a ast::Generics>,
903 impl<'a> StructParts<'a> {
904 fn format_header(&self) -> String {
905 format_header(self.prefix, self.ident, self.vis)
908 fn from_variant(variant: &'a ast::Variant) -> Self {
911 ident: variant.node.ident,
912 vis: &DEFAULT_VISIBILITY,
913 def: &variant.node.data,
919 pub fn from_item(item: &'a ast::Item) -> Self {
920 let (prefix, def, generics) = match item.node {
921 ast::ItemKind::Struct(ref def, ref generics) => ("struct ", def, generics),
922 ast::ItemKind::Union(ref def, ref generics) => ("union ", def, generics),
930 generics: Some(generics),
937 context: &RewriteContext,
938 struct_parts: &StructParts,
940 one_line_width: Option<usize>,
941 ) -> Option<String> {
942 match *struct_parts.def {
943 ast::VariantData::Unit(..) => format_unit_struct(context, struct_parts, offset),
944 ast::VariantData::Tuple(ref fields, _) => {
945 format_tuple_struct(context, struct_parts, fields, offset)
947 ast::VariantData::Struct(ref fields, _) => {
948 format_struct_struct(context, struct_parts, fields, offset, one_line_width)
953 pub fn format_trait(context: &RewriteContext, item: &ast::Item, offset: Indent) -> Option<String> {
954 if let ast::ItemKind::Trait(
958 ref type_param_bounds,
962 let mut result = String::with_capacity(128);
963 let header = format!(
965 format_auto(is_auto),
966 format_visibility(&item.vis),
967 format_unsafety(unsafety),
969 result.push_str(&header);
971 let body_lo = context.snippet_provider.span_after(item.span, "{");
973 let shape = Shape::indented(offset, context.config).offset_left(result.len())?;
974 let generics_str = rewrite_generics(
976 &item.ident.to_string(),
979 mk_sp(item.span.lo(), body_lo),
981 result.push_str(&generics_str);
983 // FIXME(#2055): rustfmt fails to format when there are comments between trait bounds.
984 if !type_param_bounds.is_empty() {
985 let ident_hi = context
987 .span_after(item.span, &format!("{}", item.ident));
988 let bound_hi = type_param_bounds.last().unwrap().span().hi();
989 let snippet = context.snippet(mk_sp(ident_hi, bound_hi));
990 if contains_comment(snippet) {
994 if !type_param_bounds.is_empty() {
995 result = rewrite_assign_rhs_with(
998 &TraitTyParamBounds::new(type_param_bounds),
1000 RhsTactics::ForceNextLine,
1004 // Rewrite where clause.
1005 if !generics.where_clause.predicates.is_empty() {
1006 let where_density = if context.config.indent_style() == IndentStyle::Block {
1012 let where_budget = context.budget(last_line_width(&result));
1013 let pos_before_where = if type_param_bounds.is_empty() {
1014 generics.where_clause.span.lo()
1016 type_param_bounds[type_param_bounds.len() - 1].span().hi()
1018 let option = WhereClauseOption::snuggled(&generics_str);
1019 let where_clause_str = rewrite_where_clause(
1021 &generics.where_clause,
1022 context.config.brace_style(),
1023 Shape::legacy(where_budget, offset.block_only()),
1031 // If the where clause cannot fit on the same line,
1032 // put the where clause on a new line
1033 if !where_clause_str.contains('\n')
1034 && last_line_width(&result) + where_clause_str.len() + offset.width()
1035 > context.config.comment_width()
1037 let width = offset.block_indent + context.config.tab_spaces() - 1;
1038 let where_indent = Indent::new(0, width);
1039 result.push_str(&where_indent.to_string_with_newline(context.config));
1041 result.push_str(&where_clause_str);
1043 let item_snippet = context.snippet(item.span);
1044 if let Some(lo) = item_snippet.find('/') {
1046 let comment_hi = body_lo - BytePos(1);
1047 let comment_lo = item.span.lo() + BytePos(lo as u32);
1048 if comment_lo < comment_hi {
1049 match recover_missing_comment_in_span(
1050 mk_sp(comment_lo, comment_hi),
1051 Shape::indented(offset, context.config),
1053 last_line_width(&result),
1055 Some(ref missing_comment) if !missing_comment.is_empty() => {
1056 result.push_str(missing_comment);
1064 match context.config.brace_style() {
1065 _ if last_line_contains_single_line_comment(&result)
1066 || last_line_width(&result) + 2 > context.budget(offset.width()) =>
1068 result.push_str(&offset.to_string_with_newline(context.config));
1070 BraceStyle::AlwaysNextLine => {
1071 result.push_str(&offset.to_string_with_newline(context.config));
1073 BraceStyle::PreferSameLine => result.push(' '),
1074 BraceStyle::SameLineWhere => {
1075 if result.contains('\n')
1076 || (!generics.where_clause.predicates.is_empty() && !trait_items.is_empty())
1078 result.push_str(&offset.to_string_with_newline(context.config));
1086 let snippet = context.snippet(item.span);
1087 let open_pos = snippet.find_uncommented("{")? + 1;
1089 if !trait_items.is_empty() || contains_comment(&snippet[open_pos..]) {
1090 let mut visitor = FmtVisitor::from_context(context);
1091 visitor.block_indent = offset.block_only().block_indent(context.config);
1092 visitor.last_pos = item.span.lo() + BytePos(open_pos as u32);
1094 for item in trait_items {
1095 visitor.visit_trait_item(item);
1098 visitor.format_missing(item.span.hi() - BytePos(1));
1100 let inner_indent_str = visitor.block_indent.to_string_with_newline(context.config);
1101 let outer_indent_str = offset.block_only().to_string_with_newline(context.config);
1103 result.push_str(&inner_indent_str);
1104 result.push_str(visitor.buffer.to_string().trim());
1105 result.push_str(&outer_indent_str);
1106 } else if result.contains('\n') {
1117 pub fn format_trait_alias(
1118 context: &RewriteContext,
1120 generics: &ast::Generics,
1121 ty_param_bounds: &ast::TyParamBounds,
1123 ) -> Option<String> {
1124 let alias = ident.name.as_str();
1125 // 6 = "trait ", 2 = " ="
1126 let g_shape = shape.offset_left(6)?.sub_width(2)?;
1127 let generics_str = rewrite_generics(context, &alias, generics, g_shape, generics.span)?;
1128 let lhs = format!("trait {} =", generics_str);
1130 rewrite_assign_rhs(context, lhs, ty_param_bounds, shape.sub_width(1)?).map(|s| s + ";")
1133 fn format_unit_struct(context: &RewriteContext, p: &StructParts, offset: Indent) -> Option<String> {
1134 let header_str = format_header(p.prefix, p.ident, p.vis);
1135 let generics_str = if let Some(generics) = p.generics {
1136 let hi = if generics.where_clause.predicates.is_empty() {
1139 generics.where_clause.span.hi()
1144 context.config.brace_style(),
1147 mk_sp(generics.span.lo(), hi),
1148 last_line_width(&header_str),
1153 Some(format!("{}{};", header_str, generics_str))
1156 pub fn format_struct_struct(
1157 context: &RewriteContext,
1158 struct_parts: &StructParts,
1159 fields: &[ast::StructField],
1161 one_line_width: Option<usize>,
1162 ) -> Option<String> {
1163 let mut result = String::with_capacity(1024);
1164 let span = struct_parts.span;
1166 let header_str = struct_parts.format_header();
1167 result.push_str(&header_str);
1169 let header_hi = span.lo() + BytePos(header_str.len() as u32);
1170 let body_lo = context.snippet_provider.span_after(span, "{");
1172 let generics_str = match struct_parts.generics {
1173 Some(g) => format_generics(
1176 context.config.brace_style(),
1177 if fields.is_empty() {
1178 BracePos::ForceSameLine
1183 mk_sp(header_hi, body_lo),
1184 last_line_width(&result),
1187 // 3 = ` {}`, 2 = ` {`.
1188 let overhead = if fields.is_empty() { 3 } else { 2 };
1189 if (context.config.brace_style() == BraceStyle::AlwaysNextLine && !fields.is_empty())
1190 || context.config.max_width() < overhead + result.len()
1192 format!("\n{}{{", offset.block_only().to_string(context.config))
1199 let overhead = if fields.is_empty() { 1 } else { 0 };
1200 let total_width = result.len() + generics_str.len() + overhead;
1201 if !generics_str.is_empty()
1202 && !generics_str.contains('\n')
1203 && total_width > context.config.max_width()
1206 result.push_str(&offset.to_string(context.config));
1207 result.push_str(generics_str.trim_left());
1209 result.push_str(&generics_str);
1212 if fields.is_empty() {
1213 let inner_span = mk_sp(body_lo, span.hi() - BytePos(1));
1214 format_empty_struct_or_tuple(context, inner_span, offset, &mut result, "", "}");
1215 return Some(result);
1219 let one_line_budget = context.budget(result.len() + 3 + offset.width());
1220 let one_line_budget =
1221 one_line_width.map_or(0, |one_line_width| min(one_line_width, one_line_budget));
1223 let items_str = rewrite_with_alignment(
1226 Shape::indented(offset, context.config).sub_width(1)?,
1227 mk_sp(body_lo, span.hi()),
1231 if !items_str.contains('\n')
1232 && !result.contains('\n')
1233 && items_str.len() <= one_line_budget
1234 && !last_line_contains_single_line_comment(&items_str)
1236 Some(format!("{} {} }}", result, items_str))
1242 .block_indent(context.config)
1243 .to_string(context.config),
1245 offset.to_string(context.config)
1250 fn get_bytepos_after_visibility(vis: &ast::Visibility, default_span: Span) -> BytePos {
1252 ast::VisibilityKind::Crate(..) | ast::VisibilityKind::Restricted { .. } => vis.span.hi(),
1253 _ => default_span.lo(),
1257 // Format tuple or struct without any fields. We need to make sure that the comments
1258 // inside the delimiters are preserved.
1259 fn format_empty_struct_or_tuple(
1260 context: &RewriteContext,
1263 result: &mut String,
1267 // 3 = " {}" or "();"
1268 let used_width = last_line_used_width(&result, offset.width()) + 3;
1269 if used_width > context.config.max_width() {
1270 result.push_str(&offset.to_string_with_newline(context.config))
1272 result.push_str(opener);
1273 match rewrite_missing_comment(span, Shape::indented(offset, context.config), context) {
1274 Some(ref s) if s.is_empty() => (),
1276 if !is_single_line(s) || first_line_contains_single_line_comment(s) {
1277 let nested_indent_str = offset
1278 .block_indent(context.config)
1279 .to_string_with_newline(context.config);
1280 result.push_str(&nested_indent_str);
1283 if last_line_contains_single_line_comment(s) {
1284 result.push_str(&offset.to_string_with_newline(context.config));
1287 None => result.push_str(context.snippet(span)),
1289 result.push_str(closer);
1292 fn format_tuple_struct(
1293 context: &RewriteContext,
1294 struct_parts: &StructParts,
1295 fields: &[ast::StructField],
1297 ) -> Option<String> {
1298 let mut result = String::with_capacity(1024);
1299 let span = struct_parts.span;
1301 let header_str = struct_parts.format_header();
1302 result.push_str(&header_str);
1304 let body_lo = if fields.is_empty() {
1305 let lo = get_bytepos_after_visibility(struct_parts.vis, span);
1308 .span_after(mk_sp(lo, span.hi()), "(")
1312 let body_hi = if fields.is_empty() {
1315 .span_after(mk_sp(body_lo, span.hi()), ")")
1317 // This is a dirty hack to work around a missing `)` from the span of the last field.
1318 let last_arg_span = fields[fields.len() - 1].span;
1319 if context.snippet(last_arg_span).ends_with(')') {
1324 .span_after(mk_sp(last_arg_span.hi(), span.hi()), ")")
1328 let where_clause_str = match struct_parts.generics {
1330 let budget = context.budget(last_line_width(&header_str));
1331 let shape = Shape::legacy(budget, offset);
1332 let g_span = mk_sp(span.lo(), body_lo);
1333 let generics_str = rewrite_generics(context, "", generics, shape, g_span)?;
1334 result.push_str(&generics_str);
1336 let where_budget = context.budget(last_line_width(&result));
1337 let option = WhereClauseOption::new(true, false);
1338 rewrite_where_clause(
1340 &generics.where_clause,
1341 context.config.brace_style(),
1342 Shape::legacy(where_budget, offset.block_only()),
1343 Density::Compressed,
1351 None => "".to_owned(),
1354 if fields.is_empty() {
1355 let body_hi = context
1357 .span_before(mk_sp(body_lo, span.hi()), ")");
1358 let inner_span = mk_sp(body_lo, body_hi);
1359 format_empty_struct_or_tuple(context, inner_span, offset, &mut result, "(", ")");
1361 let shape = Shape::indented(offset, context.config).sub_width(1)?;
1362 let fields = &fields.iter().collect::<Vec<_>>();
1363 result = overflow::rewrite_with_parens(
1369 context.config.width_heuristics().fn_call_width,
1374 if !where_clause_str.is_empty() && !where_clause_str.contains('\n')
1375 && (result.contains('\n')
1376 || offset.block_indent + result.len() + where_clause_str.len() + 1
1377 > context.config.max_width())
1379 // We need to put the where clause on a new line, but we didn't
1380 // know that earlier, so the where clause will not be indented properly.
1383 .push_str(&(offset.block_only() + (context.config.tab_spaces() - 1))
1384 .to_string(context.config));
1386 result.push_str(&where_clause_str);
1391 pub fn rewrite_type_alias(
1392 context: &RewriteContext,
1396 generics: &ast::Generics,
1397 vis: &ast::Visibility,
1399 ) -> Option<String> {
1400 let mut result = String::with_capacity(128);
1402 result.push_str(&format_visibility(vis));
1403 result.push_str("type ");
1406 let g_shape = Shape::indented(indent, context.config)
1407 .offset_left(result.len())?
1410 context.snippet_provider.span_after(span, "type"),
1413 let generics_str = rewrite_generics(context, &ident.to_string(), generics, g_shape, g_span)?;
1414 result.push_str(&generics_str);
1416 let where_budget = context.budget(last_line_width(&result));
1417 let option = WhereClauseOption::snuggled(&result);
1418 let where_clause_str = rewrite_where_clause(
1420 &generics.where_clause,
1421 context.config.brace_style(),
1422 Shape::legacy(where_budget, indent),
1430 result.push_str(&where_clause_str);
1431 if where_clause_str.is_empty() {
1432 result.push_str(" =");
1434 result.push_str(&format!(
1436 indent.to_string_with_newline(context.config)
1441 let ty_shape = Shape::indented(indent, context.config).sub_width(1)?;
1442 rewrite_assign_rhs(context, result, ty, ty_shape).map(|s| s + ";")
1445 fn type_annotation_spacing(config: &Config) -> (&str, &str) {
1447 if config.space_before_colon() { " " } else { "" },
1448 if config.space_after_colon() { " " } else { "" },
1452 pub fn rewrite_struct_field_prefix(
1453 context: &RewriteContext,
1454 field: &ast::StructField,
1455 ) -> Option<String> {
1456 let vis = format_visibility(&field.vis);
1457 let type_annotation_spacing = type_annotation_spacing(context.config);
1458 Some(match field.ident {
1459 Some(name) => format!("{}{}{}:", vis, name, type_annotation_spacing.0),
1460 None => format!("{}", vis),
1464 impl Rewrite for ast::StructField {
1465 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
1466 rewrite_struct_field(context, self, shape, 0)
1470 pub fn rewrite_struct_field(
1471 context: &RewriteContext,
1472 field: &ast::StructField,
1474 lhs_max_width: usize,
1475 ) -> Option<String> {
1476 if contains_skip(&field.attrs) {
1477 return Some(context.snippet(field.span()).to_owned());
1480 let type_annotation_spacing = type_annotation_spacing(context.config);
1481 let prefix = rewrite_struct_field_prefix(context, field)?;
1483 let attrs_str = field.attrs.rewrite(context, shape)?;
1484 let attrs_extendable = field.ident.is_none() && is_attributes_extendable(&attrs_str);
1485 let missing_span = if field.attrs.is_empty() {
1486 mk_sp(field.span.lo(), field.span.lo())
1488 mk_sp(field.attrs.last().unwrap().span.hi(), field.span.lo())
1490 let mut spacing = String::from(if field.ident.is_some() {
1491 type_annotation_spacing.1
1495 // Try to put everything on a single line.
1496 let attr_prefix = combine_strs_with_missing_comments(
1504 let overhead = last_line_width(&attr_prefix);
1505 let lhs_offset = lhs_max_width.checked_sub(overhead).unwrap_or(0);
1506 for _ in 0..lhs_offset {
1509 // In this extreme case we will be missing a space betweeen an attribute and a field.
1510 if prefix.is_empty() && !attrs_str.is_empty() && attrs_extendable && spacing.is_empty() {
1514 .offset_left(overhead + spacing.len())
1515 .and_then(|ty_shape| field.ty.rewrite(context, ty_shape));
1516 if let Some(ref ty) = orig_ty {
1517 if !ty.contains('\n') {
1518 return Some(attr_prefix + &spacing + ty);
1522 let is_prefix_empty = prefix.is_empty();
1523 // We must use multiline. We are going to put attributes and a field on different lines.
1524 let field_str = rewrite_assign_rhs(context, prefix, &*field.ty, shape)?;
1525 // Remove a leading white-space from `rewrite_assign_rhs()` when rewriting a tuple struct.
1526 let field_str = if is_prefix_empty {
1527 field_str.trim_left()
1531 combine_strs_with_missing_comments(context, &attrs_str, field_str, missing_span, shape, false)
1534 pub struct StaticParts<'a> {
1536 vis: &'a ast::Visibility,
1539 mutability: ast::Mutability,
1540 expr_opt: Option<&'a ptr::P<ast::Expr>>,
1541 defaultness: Option<ast::Defaultness>,
1545 impl<'a> StaticParts<'a> {
1546 pub fn from_item(item: &'a ast::Item) -> Self {
1547 let (prefix, ty, mutability, expr) = match item.node {
1548 ast::ItemKind::Static(ref ty, mutability, ref expr) => ("static", ty, mutability, expr),
1549 ast::ItemKind::Const(ref ty, ref expr) => {
1550 ("const", ty, ast::Mutability::Immutable, expr)
1552 _ => unreachable!(),
1560 expr_opt: Some(expr),
1566 pub fn from_trait_item(ti: &'a ast::TraitItem) -> Self {
1567 let (ty, expr_opt) = match ti.node {
1568 ast::TraitItemKind::Const(ref ty, ref expr_opt) => (ty, expr_opt),
1569 _ => unreachable!(),
1573 vis: &DEFAULT_VISIBILITY,
1576 mutability: ast::Mutability::Immutable,
1577 expr_opt: expr_opt.as_ref(),
1583 pub fn from_impl_item(ii: &'a ast::ImplItem) -> Self {
1584 let (ty, expr) = match ii.node {
1585 ast::ImplItemKind::Const(ref ty, ref expr) => (ty, expr),
1586 _ => unreachable!(),
1593 mutability: ast::Mutability::Immutable,
1594 expr_opt: Some(expr),
1595 defaultness: Some(ii.defaultness),
1602 context: &RewriteContext,
1603 static_parts: &StaticParts,
1605 ) -> Option<String> {
1606 let colon = colon_spaces(
1607 context.config.space_before_colon(),
1608 context.config.space_after_colon(),
1610 let mut prefix = format!(
1612 format_visibility(static_parts.vis),
1613 static_parts.defaultness.map_or("", format_defaultness),
1614 static_parts.prefix,
1615 format_mutability(static_parts.mutability),
1621 Shape::indented(offset.block_only(), context.config).offset_left(prefix.len() + 2)?;
1622 let ty_str = match static_parts.ty.rewrite(context, ty_shape) {
1623 Some(ty_str) => ty_str,
1625 if prefix.ends_with(' ') {
1628 let nested_indent = offset.block_indent(context.config);
1629 let nested_shape = Shape::indented(nested_indent, context.config);
1630 let ty_str = static_parts.ty.rewrite(context, nested_shape)?;
1633 nested_indent.to_string_with_newline(context.config),
1639 if let Some(expr) = static_parts.expr_opt {
1640 let lhs = format!("{}{} =", prefix, ty_str);
1642 let remaining_width = context.budget(offset.block_indent + 1);
1647 Shape::legacy(remaining_width, offset.block_only()),
1648 ).and_then(|res| recover_comment_removed(res, static_parts.span, context))
1649 .map(|s| if s.ends_with(';') { s } else { s + ";" })
1651 Some(format!("{}{};", prefix, ty_str))
1655 pub fn rewrite_associated_type(
1657 ty_opt: Option<&ptr::P<ast::Ty>>,
1658 ty_param_bounds_opt: Option<&ast::TyParamBounds>,
1659 context: &RewriteContext,
1661 ) -> Option<String> {
1662 let prefix = format!("type {}", ident);
1664 let type_bounds_str = if let Some(bounds) = ty_param_bounds_opt {
1665 if bounds.is_empty() {
1669 let shape = Shape::indented(indent, context.config).offset_left(prefix.len() + 2)?;
1670 bounds.rewrite(context, shape).map(|s| format!(": {}", s))?
1676 if let Some(ty) = ty_opt {
1678 let shape = Shape::indented(indent, context.config).sub_width(1)?;
1679 let lhs = format!("{}{} =", prefix, type_bounds_str);
1680 rewrite_assign_rhs(context, lhs, &**ty, shape).map(|s| s + ";")
1682 Some(format!("{}{};", prefix, type_bounds_str))
1686 pub fn rewrite_associated_impl_type(
1688 defaultness: ast::Defaultness,
1689 ty_opt: Option<&ptr::P<ast::Ty>>,
1690 ty_param_bounds_opt: Option<&ast::TyParamBounds>,
1691 context: &RewriteContext,
1693 ) -> Option<String> {
1694 let result = rewrite_associated_type(ident, ty_opt, ty_param_bounds_opt, context, indent)?;
1697 ast::Defaultness::Default => Some(format!("default {}", result)),
1702 impl Rewrite for ast::FunctionRetTy {
1703 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
1705 ast::FunctionRetTy::Default(_) => Some(String::new()),
1706 ast::FunctionRetTy::Ty(ref ty) => {
1707 let inner_width = shape.width.checked_sub(3)?;
1708 ty.rewrite(context, Shape::legacy(inner_width, shape.indent + 3))
1709 .map(|r| format!("-> {}", r))
1715 fn is_empty_infer(context: &RewriteContext, ty: &ast::Ty) -> bool {
1717 ast::TyKind::Infer => {
1718 let original = context.snippet(ty.span);
1725 impl Rewrite for ast::Arg {
1726 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
1727 if is_named_arg(self) {
1728 let mut result = self.pat
1729 .rewrite(context, Shape::legacy(shape.width, shape.indent))?;
1731 if !is_empty_infer(context, &*self.ty) {
1732 if context.config.space_before_colon() {
1733 result.push_str(" ");
1735 result.push_str(":");
1736 if context.config.space_after_colon() {
1737 result.push_str(" ");
1739 let overhead = last_line_width(&result);
1740 let max_width = shape.width.checked_sub(overhead)?;
1741 let ty_str = self.ty
1742 .rewrite(context, Shape::legacy(max_width, shape.indent))?;
1743 result.push_str(&ty_str);
1748 self.ty.rewrite(context, shape)
1753 fn rewrite_explicit_self(
1754 explicit_self: &ast::ExplicitSelf,
1756 context: &RewriteContext,
1757 ) -> Option<String> {
1758 match explicit_self.node {
1759 ast::SelfKind::Region(lt, m) => {
1760 let mut_str = format_mutability(m);
1763 let lifetime_str = l.rewrite(
1765 Shape::legacy(context.config.max_width(), Indent::empty()),
1767 Some(format!("&{} {}self", lifetime_str, mut_str))
1769 None => Some(format!("&{}self", mut_str)),
1772 ast::SelfKind::Explicit(ref ty, _) => {
1773 assert!(!args.is_empty(), "&[ast::Arg] shouldn't be empty.");
1775 let mutability = explicit_self_mutability(&args[0]);
1776 let type_str = ty.rewrite(
1778 Shape::legacy(context.config.max_width(), Indent::empty()),
1783 format_mutability(mutability),
1787 ast::SelfKind::Value(_) => {
1788 assert!(!args.is_empty(), "&[ast::Arg] shouldn't be empty.");
1790 let mutability = explicit_self_mutability(&args[0]);
1792 Some(format!("{}self", format_mutability(mutability)))
1797 // Hacky solution caused by absence of `Mutability` in `SelfValue` and
1798 // `SelfExplicit` variants of `ast::ExplicitSelf_`.
1799 fn explicit_self_mutability(arg: &ast::Arg) -> ast::Mutability {
1800 if let ast::PatKind::Ident(ast::BindingMode::ByValue(mutability), _, _) = arg.pat.node {
1807 pub fn span_lo_for_arg(arg: &ast::Arg) -> BytePos {
1808 if is_named_arg(arg) {
1815 pub fn span_hi_for_arg(context: &RewriteContext, arg: &ast::Arg) -> BytePos {
1817 ast::TyKind::Infer if context.snippet(arg.ty.span) == "_" => arg.ty.span.hi(),
1818 ast::TyKind::Infer if is_named_arg(arg) => arg.pat.span.hi(),
1819 _ => arg.ty.span.hi(),
1823 pub fn is_named_arg(arg: &ast::Arg) -> bool {
1824 if let ast::PatKind::Ident(_, ident, _) = arg.pat.node {
1825 ident != symbol::keywords::Invalid.ident()
1831 // Return type is (result, force_new_line_for_brace)
1833 context: &RewriteContext,
1838 newline_brace: bool,
1840 ) -> Option<(String, bool)> {
1841 let mut force_new_line_for_brace = false;
1843 let where_clause = &fn_sig.generics.where_clause;
1845 let mut result = String::with_capacity(1024);
1846 result.push_str(&fn_sig.to_str(context));
1849 result.push_str("fn ");
1852 let overhead = if has_body && !newline_brace {
1859 let used_width = last_line_used_width(&result, indent.width());
1860 let one_line_budget = context.budget(used_width + overhead);
1862 width: one_line_budget,
1866 let fd = fn_sig.decl;
1867 let g_span = mk_sp(span.lo(), fd.output.span().lo());
1869 rewrite_generics(context, &ident.to_string(), fn_sig.generics, shape, g_span)?;
1870 result.push_str(&generics_str);
1872 let snuggle_angle_bracket = generics_str
1875 .map_or(false, |l| l.trim_left().len() == 1);
1877 // Note that the width and indent don't really matter, we'll re-layout the
1878 // return type later anyway.
1879 let ret_str = fd.output
1880 .rewrite(context, Shape::indented(indent, context.config))?;
1882 let multi_line_ret_str = ret_str.contains('\n');
1883 let ret_str_len = if multi_line_ret_str { 0 } else { ret_str.len() };
1886 let (one_line_budget, multi_line_budget, mut arg_indent) = compute_budgets_for_args(
1897 "rewrite_fn_base: one_line_budget: {}, multi_line_budget: {}, arg_indent: {:?}",
1898 one_line_budget, multi_line_budget, arg_indent
1901 // Check if vertical layout was forced.
1902 if one_line_budget == 0 {
1903 if snuggle_angle_bracket {
1906 result.push_str("(");
1907 if context.config.indent_style() == IndentStyle::Visual {
1908 result.push_str(&arg_indent.to_string_with_newline(context.config));
1914 if context.config.spaces_within_parens_and_brackets()
1915 && !fd.inputs.is_empty()
1916 && result.ends_with('(')
1921 // Skip `pub(crate)`.
1922 let lo_after_visibility = get_bytepos_after_visibility(&fn_sig.visibility, span);
1923 // A conservative estimation, to goal is to be over all parens in generics
1924 let args_start = fn_sig
1929 .map_or(lo_after_visibility, |param| param.span().hi());
1930 let args_end = if fd.inputs.is_empty() {
1933 .span_after(mk_sp(args_start, span.hi()), ")")
1935 let last_span = mk_sp(fd.inputs[fd.inputs.len() - 1].span().hi(), span.hi());
1936 context.snippet_provider.span_after(last_span, ")")
1938 let args_span = mk_sp(
1941 .span_after(mk_sp(args_start, span.hi()), "("),
1944 let arg_str = rewrite_args(
1947 fd.get_self().as_ref(),
1954 generics_str.contains('\n'),
1957 let put_args_in_block = match context.config.indent_style() {
1958 IndentStyle::Block => arg_str.contains('\n') || arg_str.len() > one_line_budget,
1960 } && !fd.inputs.is_empty();
1962 let mut args_last_line_contains_comment = false;
1963 if put_args_in_block {
1964 arg_indent = indent.block_indent(context.config);
1965 result.push_str(&arg_indent.to_string_with_newline(context.config));
1966 result.push_str(&arg_str);
1967 result.push_str(&indent.to_string_with_newline(context.config));
1970 result.push_str(&arg_str);
1971 let used_width = last_line_used_width(&result, indent.width()) + first_line_width(&ret_str);
1972 // Put the closing brace on the next line if it overflows the max width.
1974 if fd.inputs.is_empty() && used_width + 1 > context.config.max_width() {
1977 if context.config.spaces_within_parens_and_brackets() && !fd.inputs.is_empty() {
1980 // If the last line of args contains comment, we cannot put the closing paren
1981 // on the same line.
1985 .map_or(false, |last_line| last_line.contains("//"))
1987 args_last_line_contains_comment = true;
1988 result.push_str(&arg_indent.to_string_with_newline(context.config));
1994 if let ast::FunctionRetTy::Ty(..) = fd.output {
1995 let ret_should_indent = match context.config.indent_style() {
1996 // If our args are block layout then we surely must have space.
1997 IndentStyle::Block if put_args_in_block || fd.inputs.is_empty() => false,
1998 _ if args_last_line_contains_comment => false,
1999 _ if result.contains('\n') || multi_line_ret_str => true,
2001 // If the return type would push over the max width, then put the return type on
2002 // a new line. With the +1 for the signature length an additional space between
2003 // the closing parenthesis of the argument and the arrow '->' is considered.
2004 let mut sig_length = result.len() + indent.width() + ret_str_len + 1;
2006 // If there is no where clause, take into account the space after the return type
2008 if where_clause.predicates.is_empty() {
2012 sig_length > context.config.max_width()
2015 let ret_indent = if ret_should_indent {
2016 let indent = if arg_str.is_empty() {
2017 // Aligning with non-existent args looks silly.
2018 force_new_line_for_brace = true;
2021 // FIXME: we might want to check that using the arg indent
2022 // doesn't blow our budget, and if it does, then fallback to
2023 // the where clause indent.
2027 result.push_str(&indent.to_string_with_newline(context.config));
2031 Indent::new(indent.block_indent, last_line_width(&result))
2034 if multi_line_ret_str || ret_should_indent {
2035 // Now that we know the proper indent and width, we need to
2036 // re-layout the return type.
2037 let ret_str = fd.output
2038 .rewrite(context, Shape::indented(ret_indent, context.config))?;
2039 result.push_str(&ret_str);
2041 result.push_str(&ret_str);
2044 // Comment between return type and the end of the decl.
2045 let snippet_lo = fd.output.span().hi();
2046 if where_clause.predicates.is_empty() {
2047 let snippet_hi = span.hi();
2048 let snippet = context.snippet(mk_sp(snippet_lo, snippet_hi));
2049 // Try to preserve the layout of the original snippet.
2050 let original_starts_with_newline = snippet
2052 .map_or(false, |i| starts_with_newline(&snippet[i..]));
2053 let original_ends_with_newline = snippet
2054 .rfind(|c| c != ' ')
2055 .map_or(false, |i| snippet[i..].ends_with('\n'));
2056 let snippet = snippet.trim();
2057 if !snippet.is_empty() {
2058 result.push(if original_starts_with_newline {
2063 result.push_str(snippet);
2064 if original_ends_with_newline {
2065 force_new_line_for_brace = true;
2071 let pos_before_where = match fd.output {
2072 ast::FunctionRetTy::Default(..) => args_span.hi(),
2073 ast::FunctionRetTy::Ty(ref ty) => ty.span.hi(),
2076 let is_args_multi_lined = arg_str.contains('\n');
2078 let option = WhereClauseOption::new(!has_body, put_args_in_block && ret_str.is_empty());
2079 let where_clause_str = rewrite_where_clause(
2082 context.config.brace_style(),
2083 Shape::indented(indent, context.config),
2089 is_args_multi_lined,
2091 // If there are neither where clause nor return type, we may be missing comments between
2093 if where_clause_str.is_empty() {
2094 if let ast::FunctionRetTy::Default(ret_span) = fd.output {
2095 match recover_missing_comment_in_span(
2096 mk_sp(args_span.hi(), ret_span.hi()),
2099 last_line_width(&result),
2101 Some(ref missing_comment) if !missing_comment.is_empty() => {
2102 result.push_str(missing_comment);
2103 force_new_line_for_brace = true;
2110 result.push_str(&where_clause_str);
2112 force_new_line_for_brace |= last_line_contains_single_line_comment(&result);
2113 force_new_line_for_brace |= is_args_multi_lined && context.config.where_single_line();
2114 Some((result, force_new_line_for_brace))
2117 #[derive(Copy, Clone)]
2118 struct WhereClauseOption {
2119 suppress_comma: bool, // Force no trailing comma
2120 snuggle: bool, // Do not insert newline before `where`
2121 compress_where: bool, // Try single line where clause instead of vertical layout
2124 impl WhereClauseOption {
2125 pub fn new(suppress_comma: bool, snuggle: bool) -> WhereClauseOption {
2129 compress_where: false,
2133 pub fn snuggled(current: &str) -> WhereClauseOption {
2135 suppress_comma: false,
2136 snuggle: trimmed_last_line_width(current) == 1,
2137 compress_where: false,
2143 context: &RewriteContext,
2145 explicit_self: Option<&ast::ExplicitSelf>,
2146 one_line_budget: usize,
2147 multi_line_budget: usize,
2152 generics_str_contains_newline: bool,
2153 ) -> Option<String> {
2154 let mut arg_item_strs = args.iter()
2155 .map(|arg| arg.rewrite(context, Shape::legacy(multi_line_budget, arg_indent)))
2156 .collect::<Option<Vec<_>>>()?;
2158 // Account for sugary self.
2159 // FIXME: the comment for the self argument is dropped. This is blocked
2160 // on rust issue #27522.
2161 let min_args = explicit_self
2162 .and_then(|explicit_self| rewrite_explicit_self(explicit_self, args, context))
2163 .map_or(1, |self_str| {
2164 arg_item_strs[0] = self_str;
2168 // Comments between args.
2169 let mut arg_items = Vec::new();
2171 arg_items.push(ListItem::from_str(""));
2174 // FIXME(#21): if there are no args, there might still be a comment, but
2175 // without spans for the comment or parens, there is no chance of
2176 // getting it right. You also don't get to put a comment on self, unless
2178 if args.len() >= min_args || variadic {
2179 let comment_span_start = if min_args == 2 {
2180 let second_arg_start = if arg_has_pattern(&args[1]) {
2181 args[1].pat.span.lo()
2183 args[1].ty.span.lo()
2185 let reduced_span = mk_sp(span.lo(), second_arg_start);
2187 context.snippet_provider.span_after_last(reduced_span, ",")
2192 enum ArgumentKind<'a> {
2193 Regular(&'a ast::Arg),
2197 let variadic_arg = if variadic {
2198 let variadic_span = mk_sp(args.last().unwrap().ty.span.hi(), span.hi());
2199 let variadic_start =
2200 context.snippet_provider.span_after(variadic_span, "...") - BytePos(3);
2201 Some(ArgumentKind::Variadic(variadic_start))
2206 let more_items = itemize_list(
2207 context.snippet_provider,
2208 args[min_args - 1..]
2210 .map(ArgumentKind::Regular)
2211 .chain(variadic_arg),
2215 ArgumentKind::Regular(arg) => span_lo_for_arg(arg),
2216 ArgumentKind::Variadic(start) => start,
2219 ArgumentKind::Regular(arg) => arg.ty.span.hi(),
2220 ArgumentKind::Variadic(start) => start + BytePos(3),
2223 ArgumentKind::Regular(..) => None,
2224 ArgumentKind::Variadic(..) => Some("...".to_owned()),
2231 arg_items.extend(more_items);
2234 let fits_in_one_line = !generics_str_contains_newline
2235 && (arg_items.is_empty()
2236 || arg_items.len() == 1 && arg_item_strs[0].len() <= one_line_budget);
2238 for (item, arg) in arg_items.iter_mut().zip(arg_item_strs) {
2239 item.item = Some(arg);
2242 let last_line_ends_with_comment = arg_items
2245 .and_then(|item| item.post_comment.as_ref())
2246 .map_or(false, |s| s.trim().starts_with("//"));
2248 let (indent, trailing_comma) = match context.config.indent_style() {
2249 IndentStyle::Block if fits_in_one_line => {
2250 (indent.block_indent(context.config), SeparatorTactic::Never)
2252 IndentStyle::Block => (
2253 indent.block_indent(context.config),
2254 context.config.trailing_comma(),
2256 IndentStyle::Visual if last_line_ends_with_comment => {
2257 (arg_indent, context.config.trailing_comma())
2259 IndentStyle::Visual => (arg_indent, SeparatorTactic::Never),
2262 let tactic = definitive_tactic(
2264 context.config.fn_args_density().to_list_tactic(),
2268 let budget = match tactic {
2269 DefinitiveListTactic::Horizontal => one_line_budget,
2270 _ => multi_line_budget,
2273 debug!("rewrite_args: budget: {}, tactic: {:?}", budget, tactic);
2275 let fmt = ListFormatting {
2278 trailing_separator: if variadic {
2279 SeparatorTactic::Never
2283 separator_place: SeparatorPlace::Back,
2284 shape: Shape::legacy(budget, indent),
2285 ends_with_newline: tactic.ends_with_newline(context.config.indent_style()),
2286 preserve_newline: true,
2287 config: context.config,
2290 write_list(&arg_items, &fmt)
2293 fn arg_has_pattern(arg: &ast::Arg) -> bool {
2294 if let ast::PatKind::Ident(_, ident, _) = arg.pat.node {
2295 ident != symbol::keywords::Invalid.ident()
2301 fn compute_budgets_for_args(
2302 context: &RewriteContext,
2306 newline_brace: bool,
2308 force_vertical_layout: bool,
2309 ) -> Option<((usize, usize, Indent))> {
2311 "compute_budgets_for_args {} {:?}, {}, {}",
2317 // Try keeping everything on the same line.
2318 if !result.contains('\n') && !force_vertical_layout {
2319 // 2 = `()`, 3 = `() `, space is before ret_string.
2320 let overhead = if ret_str_len == 0 { 2 } else { 3 };
2321 let mut used_space = indent.width() + result.len() + ret_str_len + overhead;
2331 let one_line_budget = context.budget(used_space);
2333 if one_line_budget > 0 {
2335 let (indent, multi_line_budget) = match context.config.indent_style() {
2336 IndentStyle::Block => {
2337 let indent = indent.block_indent(context.config);
2338 (indent, context.budget(indent.width() + 1))
2340 IndentStyle::Visual => {
2341 let indent = indent + result.len() + 1;
2342 let multi_line_overhead = indent.width() + if newline_brace { 2 } else { 4 };
2343 (indent, context.budget(multi_line_overhead))
2347 return Some((one_line_budget, multi_line_budget, indent));
2351 // Didn't work. we must force vertical layout and put args on a newline.
2352 let new_indent = indent.block_indent(context.config);
2353 let used_space = match context.config.indent_style() {
2355 IndentStyle::Block => new_indent.width() + 1,
2356 // Account for `)` and possibly ` {`.
2357 IndentStyle::Visual => new_indent.width() + if ret_str_len == 0 { 1 } else { 3 },
2359 Some((0, context.budget(used_space), new_indent))
2362 fn newline_for_brace(config: &Config, where_clause: &ast::WhereClause) -> bool {
2363 let predicate_count = where_clause.predicates.len();
2365 if config.where_single_line() && predicate_count == 1 {
2368 let brace_style = config.brace_style();
2370 brace_style == BraceStyle::AlwaysNextLine
2371 || (brace_style == BraceStyle::SameLineWhere && predicate_count > 0)
2374 fn rewrite_generics(
2375 context: &RewriteContext,
2377 generics: &ast::Generics,
2380 ) -> Option<String> {
2381 // FIXME: convert bounds to where clauses where they get too big or if
2382 // there is a where clause at all.
2384 if generics.params.is_empty() {
2385 return Some(ident.to_owned());
2388 let params = &generics.params.iter().map(|e| &*e).collect::<Vec<_>>();
2389 overflow::rewrite_with_angle_brackets(context, ident, params, shape, span)
2392 pub fn generics_shape_from_config(config: &Config, shape: Shape, offset: usize) -> Option<Shape> {
2393 match config.indent_style() {
2394 IndentStyle::Visual => shape.visual_indent(1 + offset).sub_width(offset + 2),
2395 IndentStyle::Block => {
2399 .block_indent(config.tab_spaces())
2400 .with_max_width(config)
2406 fn rewrite_where_clause_rfc_style(
2407 context: &RewriteContext,
2408 where_clause: &ast::WhereClause,
2411 span_end: Option<BytePos>,
2412 span_end_before_where: BytePos,
2413 where_clause_option: WhereClauseOption,
2414 is_args_multi_line: bool,
2415 ) -> Option<String> {
2416 let block_shape = shape.block().with_max_width(context.config);
2418 let (span_before, span_after) =
2419 missing_span_before_after_where(span_end_before_where, where_clause);
2420 let (comment_before, comment_after) =
2421 rewrite_comments_before_after_where(context, span_before, span_after, shape)?;
2423 let starting_newline = if where_clause_option.snuggle && comment_before.is_empty() {
2426 block_shape.indent.to_string_with_newline(context.config)
2429 let clause_shape = block_shape.block_left(context.config.tab_spaces())?;
2431 let clause_shape = clause_shape.sub_width(1)?;
2432 // each clause on one line, trailing comma (except if suppress_comma)
2433 let span_start = where_clause.predicates[0].span().lo();
2434 // If we don't have the start of the next span, then use the end of the
2435 // predicates, but that means we miss comments.
2436 let len = where_clause.predicates.len();
2437 let end_of_preds = where_clause.predicates[len - 1].span().hi();
2438 let span_end = span_end.unwrap_or(end_of_preds);
2439 let items = itemize_list(
2440 context.snippet_provider,
2441 where_clause.predicates.iter(),
2444 |pred| pred.span().lo(),
2445 |pred| pred.span().hi(),
2446 |pred| pred.rewrite(context, clause_shape),
2451 let where_single_line = context.config.where_single_line() && len == 1 && !is_args_multi_line;
2452 let comma_tactic = if where_clause_option.suppress_comma || where_single_line {
2453 SeparatorTactic::Never
2455 context.config.trailing_comma()
2458 // shape should be vertical only and only if we have `where_single_line` option enabled
2459 // and the number of items of the where clause is equal to 1
2460 let shape_tactic = if where_single_line {
2461 DefinitiveListTactic::Horizontal
2463 DefinitiveListTactic::Vertical
2466 let fmt = ListFormatting {
2467 tactic: shape_tactic,
2469 trailing_separator: comma_tactic,
2470 separator_place: SeparatorPlace::Back,
2471 shape: clause_shape,
2472 ends_with_newline: true,
2473 preserve_newline: true,
2474 config: context.config,
2476 let preds_str = write_list(&items.collect::<Vec<_>>(), &fmt)?;
2478 let comment_separator = |comment: &str, shape: Shape| {
2479 if comment.is_empty() {
2482 shape.indent.to_string_with_newline(context.config)
2485 let newline_before_where = comment_separator(&comment_before, shape);
2486 let newline_after_where = comment_separator(&comment_after, clause_shape);
2489 let clause_sep = if where_clause_option.compress_where
2490 && comment_before.is_empty()
2491 && comment_after.is_empty()
2492 && !preds_str.contains('\n')
2493 && 6 + preds_str.len() <= shape.width || where_single_line
2497 clause_shape.indent.to_string_with_newline(context.config)
2500 "{}{}{}where{}{}{}{}",
2503 newline_before_where,
2504 newline_after_where,
2511 fn rewrite_where_clause(
2512 context: &RewriteContext,
2513 where_clause: &ast::WhereClause,
2514 brace_style: BraceStyle,
2518 span_end: Option<BytePos>,
2519 span_end_before_where: BytePos,
2520 where_clause_option: WhereClauseOption,
2521 is_args_multi_line: bool,
2522 ) -> Option<String> {
2523 if where_clause.predicates.is_empty() {
2524 return Some(String::new());
2527 if context.config.indent_style() == IndentStyle::Block {
2528 return rewrite_where_clause_rfc_style(
2534 span_end_before_where,
2535 where_clause_option,
2540 let extra_indent = Indent::new(context.config.tab_spaces(), 0);
2542 let offset = match context.config.indent_style() {
2543 IndentStyle::Block => shape.indent + extra_indent.block_indent(context.config),
2544 // 6 = "where ".len()
2545 IndentStyle::Visual => shape.indent + extra_indent + 6,
2547 // FIXME: if indent_style != Visual, then the budgets below might
2548 // be out by a char or two.
2550 let budget = context.config.max_width() - offset.width();
2551 let span_start = where_clause.predicates[0].span().lo();
2552 // If we don't have the start of the next span, then use the end of the
2553 // predicates, but that means we miss comments.
2554 let len = where_clause.predicates.len();
2555 let end_of_preds = where_clause.predicates[len - 1].span().hi();
2556 let span_end = span_end.unwrap_or(end_of_preds);
2557 let items = itemize_list(
2558 context.snippet_provider,
2559 where_clause.predicates.iter(),
2562 |pred| pred.span().lo(),
2563 |pred| pred.span().hi(),
2564 |pred| pred.rewrite(context, Shape::legacy(budget, offset)),
2569 let item_vec = items.collect::<Vec<_>>();
2570 // FIXME: we don't need to collect here
2571 let tactic = definitive_tactic(&item_vec, ListTactic::Vertical, Separator::Comma, budget);
2573 let mut comma_tactic = context.config.trailing_comma();
2574 // Kind of a hack because we don't usually have trailing commas in where clauses.
2575 if comma_tactic == SeparatorTactic::Vertical || where_clause_option.suppress_comma {
2576 comma_tactic = SeparatorTactic::Never;
2579 let fmt = ListFormatting {
2582 trailing_separator: comma_tactic,
2583 separator_place: SeparatorPlace::Back,
2584 shape: Shape::legacy(budget, offset),
2585 ends_with_newline: tactic.ends_with_newline(context.config.indent_style()),
2586 preserve_newline: true,
2587 config: context.config,
2589 let preds_str = write_list(&item_vec, &fmt)?;
2591 let end_length = if terminator == "{" {
2592 // If the brace is on the next line we don't need to count it otherwise it needs two
2595 BraceStyle::AlwaysNextLine | BraceStyle::SameLineWhere => 0,
2596 BraceStyle::PreferSameLine => 2,
2598 } else if terminator == "=" {
2603 if density == Density::Tall
2604 || preds_str.contains('\n')
2605 || shape.indent.width() + " where ".len() + preds_str.len() + end_length > shape.width
2609 (shape.indent + extra_indent).to_string(context.config),
2613 Some(format!(" where {}", preds_str))
2617 fn missing_span_before_after_where(
2618 before_item_span_end: BytePos,
2619 where_clause: &ast::WhereClause,
2621 let missing_span_before = mk_sp(before_item_span_end, where_clause.span.lo());
2623 let pos_after_where = where_clause.span.lo() + BytePos(5);
2624 let missing_span_after = mk_sp(pos_after_where, where_clause.predicates[0].span().lo());
2625 (missing_span_before, missing_span_after)
2628 fn rewrite_comments_before_after_where(
2629 context: &RewriteContext,
2630 span_before_where: Span,
2631 span_after_where: Span,
2633 ) -> Option<(String, String)> {
2634 let before_comment = rewrite_missing_comment(span_before_where, shape, context)?;
2635 let after_comment = rewrite_missing_comment(
2637 shape.block_indent(context.config.tab_spaces()),
2640 Some((before_comment, after_comment))
2643 fn format_header(item_name: &str, ident: ast::Ident, vis: &ast::Visibility) -> String {
2644 format!("{}{}{}", format_visibility(vis), item_name, ident)
2647 #[derive(PartialEq, Eq, Clone, Copy)]
2655 context: &RewriteContext,
2656 generics: &ast::Generics,
2657 brace_style: BraceStyle,
2658 brace_pos: BracePos,
2662 ) -> Option<String> {
2663 let shape = Shape::legacy(context.budget(used_width + offset.width()), offset);
2664 let mut result = rewrite_generics(context, "", generics, shape, span)?;
2666 let same_line_brace = if !generics.where_clause.predicates.is_empty() || result.contains('\n') {
2667 let budget = context.budget(last_line_used_width(&result, offset.width()));
2668 let mut option = WhereClauseOption::snuggled(&result);
2669 if brace_pos == BracePos::None {
2670 option.suppress_comma = true;
2672 // If the generics are not parameterized then generics.span.hi() == 0,
2673 // so we use span.lo(), which is the position after `struct Foo`.
2674 let span_end_before_where = if generics.is_parameterized() {
2679 let where_clause_str = rewrite_where_clause(
2681 &generics.where_clause,
2683 Shape::legacy(budget, offset.block_only()),
2687 span_end_before_where,
2691 result.push_str(&where_clause_str);
2692 brace_pos == BracePos::ForceSameLine || brace_style == BraceStyle::PreferSameLine
2693 || (generics.where_clause.predicates.is_empty()
2694 && trimmed_last_line_width(&result) == 1)
2696 brace_pos == BracePos::ForceSameLine
2697 || trimmed_last_line_width(&result) == 1
2698 || brace_style != BraceStyle::AlwaysNextLine
2700 if brace_pos == BracePos::None {
2701 return Some(result);
2703 let total_used_width = last_line_used_width(&result, used_width);
2704 let remaining_budget = context.budget(total_used_width);
2705 // If the same line brace if forced, it indicates that we are rewriting an item with empty body,
2706 // and hence we take the closer into account as well for one line budget.
2707 // We assume that the closer has the same length as the opener.
2708 let overhead = if brace_pos == BracePos::ForceSameLine {
2715 let forbid_same_line_brace = overhead > remaining_budget;
2716 if !forbid_same_line_brace && same_line_brace {
2720 result.push_str(&offset.block_only().to_string(context.config));
2727 impl Rewrite for ast::ForeignItem {
2728 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
2729 let attrs_str = self.attrs.rewrite(context, shape)?;
2730 // Drop semicolon or it will be interpreted as comment.
2731 // FIXME: this may be a faulty span from libsyntax.
2732 let span = mk_sp(self.span.lo(), self.span.hi() - BytePos(1));
2734 let item_str = match self.node {
2735 ast::ForeignItemKind::Fn(ref fn_decl, ref generics) => {
2740 &FnSig::new(fn_decl, generics, self.vis.clone()),
2744 ).map(|(s, _)| format!("{};", s))
2746 ast::ForeignItemKind::Static(ref ty, is_mutable) => {
2747 // FIXME(#21): we're dropping potential comments in between the
2748 // function keywords here.
2749 let vis = format_visibility(&self.vis);
2750 let mut_str = if is_mutable { "mut " } else { "" };
2751 let prefix = format!("{}static {}{}:", vis, mut_str, self.ident);
2753 rewrite_assign_rhs(context, prefix, &**ty, shape.sub_width(1)?).map(|s| s + ";")
2755 ast::ForeignItemKind::Ty => {
2756 let vis = format_visibility(&self.vis);
2757 Some(format!("{}type {};", vis, self.ident))
2759 ast::ForeignItemKind::Macro(ref mac) => {
2760 rewrite_macro(mac, None, context, shape, MacroPosition::Item)
2764 let missing_span = if self.attrs.is_empty() {
2765 mk_sp(self.span.lo(), self.span.lo())
2767 mk_sp(self.attrs[self.attrs.len() - 1].span.hi(), self.span.lo())
2769 combine_strs_with_missing_comments(
2780 impl Rewrite for ast::GenericParam {
2781 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
2783 ast::GenericParam::Lifetime(ref lifetime_def) => lifetime_def.rewrite(context, shape),
2784 ast::GenericParam::Type(ref ty) => ty.rewrite(context, shape),
2789 /// Rewrite an inline mod.
2790 pub fn rewrite_mod(item: &ast::Item) -> String {
2791 let mut result = String::with_capacity(32);
2792 result.push_str(&*format_visibility(&item.vis));
2793 result.push_str("mod ");
2794 result.push_str(&item.ident.to_string());
2799 /// Rewrite `extern crate foo;` WITHOUT attributes.
2800 pub fn rewrite_extern_crate(context: &RewriteContext, item: &ast::Item) -> Option<String> {
2801 assert!(is_extern_crate(item));
2802 let new_str = context.snippet(item.span);
2803 Some(if contains_comment(new_str) {
2806 let no_whitespace = &new_str.split_whitespace().collect::<Vec<&str>>().join(" ");
2807 String::from(&*Regex::new(r"\s;").unwrap().replace(no_whitespace, ";"))
2811 /// Returns true for `mod foo;`, false for `mod foo { .. }`.
2812 pub fn is_mod_decl(item: &ast::Item) -> bool {
2814 ast::ItemKind::Mod(ref m) => m.inner.hi() != item.span.hi(),
2819 pub fn is_use_item(item: &ast::Item) -> bool {
2821 ast::ItemKind::Use(_) => true,
2826 pub fn is_extern_crate(item: &ast::Item) -> bool {
2828 ast::ItemKind::ExternCrate(..) => true,