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)
584 context: &RewriteContext,
587 where_span_end: Option<BytePos>,
588 ) -> Option<String> {
589 if let ast::ItemKind::Impl(_, _, _, ref generics, _, ref self_ty, ref items) = item.node {
590 let mut result = String::with_capacity(128);
591 let ref_and_type = format_impl_ref_and_type(context, item, offset)?;
592 let sep = offset.to_string_with_newline(context.config);
593 result.push_str(&ref_and_type);
595 let where_budget = if result.contains('\n') {
596 context.config.max_width()
598 context.budget(last_line_width(&result))
600 let option = WhereClauseOption::snuggled(&ref_and_type);
601 let where_clause_str = rewrite_where_clause(
603 &generics.where_clause,
604 context.config.brace_style(),
605 Shape::legacy(where_budget, offset.block_only()),
614 // If there is no where clause, we may have missing comments between the trait name and
615 // the opening brace.
616 if generics.where_clause.predicates.is_empty() {
617 if let Some(hi) = where_span_end {
618 match recover_missing_comment_in_span(
619 mk_sp(self_ty.span.hi(), hi),
620 Shape::indented(offset, context.config),
622 last_line_width(&result),
624 Some(ref missing_comment) if !missing_comment.is_empty() => {
625 result.push_str(missing_comment);
632 if is_impl_single_line(context, items, &result, &where_clause_str, item)? {
633 result.push_str(&where_clause_str);
634 if where_clause_str.contains('\n') || last_line_contains_single_line_comment(&result) {
635 result.push_str(&format!("{}{{{}}}", &sep, &sep));
637 result.push_str(" {}");
642 if !where_clause_str.is_empty() && !where_clause_str.contains('\n') {
643 let width = offset.block_indent + context.config.tab_spaces() - 1;
644 let where_indent = Indent::new(0, width);
645 result.push_str(&where_indent.to_string_with_newline(context.config));
647 result.push_str(&where_clause_str);
649 let need_newline = last_line_contains_single_line_comment(&result) || result.contains('\n');
650 match context.config.brace_style() {
651 _ if need_newline => result.push_str(&sep),
652 BraceStyle::AlwaysNextLine => result.push_str(&sep),
653 BraceStyle::PreferSameLine => result.push(' '),
654 BraceStyle::SameLineWhere => {
655 if !where_clause_str.is_empty() {
656 result.push_str(&sep);
665 let snippet = context.snippet(item.span);
666 let open_pos = snippet.find_uncommented("{")? + 1;
668 if !items.is_empty() || contains_comment(&snippet[open_pos..]) {
669 let mut visitor = FmtVisitor::from_context(context);
670 let item_indent = offset.block_only().block_indent(context.config);
671 visitor.block_indent = item_indent;
672 visitor.last_pos = item.span.lo() + BytePos(open_pos as u32);
674 visitor.visit_attrs(&item.attrs, ast::AttrStyle::Inner);
675 if context.config.reorder_impl_items() {
676 // Create visitor for each items, then reorder them.
677 let mut buffer = vec![];
679 visitor.visit_impl_item(item);
680 buffer.push((visitor.buffer.clone(), item.clone()));
681 visitor.buffer.clear();
683 // type -> const -> macro -> method
684 use ast::ImplItemKind::*;
685 fn need_empty_line(a: &ast::ImplItemKind, b: &ast::ImplItemKind) -> bool {
687 (Type(..), Type(..)) | (Const(..), Const(..)) => false,
692 buffer.sort_by(|(_, a), (_, b)| match (&a.node, &b.node) {
693 (Type(..), _) => Ordering::Less,
694 (_, Type(..)) => Ordering::Greater,
695 (Const(..), _) => Ordering::Less,
696 (_, Const(..)) => Ordering::Greater,
697 (Macro(..), _) => Ordering::Less,
698 (_, Macro(..)) => Ordering::Greater,
701 let mut prev_kind = None;
702 for (buf, item) in buffer {
703 // Make sure that there are at least a single empty line between
704 // different impl items.
707 .map_or(false, |prev_kind| need_empty_line(prev_kind, &item.node))
709 visitor.push_str("\n");
711 visitor.push_str(&item_indent.to_string_with_newline(context.config));
712 visitor.push_str(buf.trim());
713 prev_kind = Some(item.node.clone());
717 visitor.visit_impl_item(item);
721 visitor.format_missing(item.span.hi() - BytePos(1));
723 let inner_indent_str = visitor.block_indent.to_string_with_newline(context.config);
724 let outer_indent_str = offset.block_only().to_string_with_newline(context.config);
726 result.push_str(&inner_indent_str);
727 result.push_str(visitor.buffer.to_string().trim());
728 result.push_str(&outer_indent_str);
731 if result.ends_with('{') {
732 result.push_str(&sep);
742 fn is_impl_single_line(
743 context: &RewriteContext,
744 items: &[ast::ImplItem],
746 where_clause_str: &str,
749 let snippet = context.snippet(item.span);
750 let open_pos = snippet.find_uncommented("{")? + 1;
753 context.config.empty_item_single_line() && items.is_empty() && !result.contains('\n')
754 && result.len() + where_clause_str.len() <= context.config.max_width()
755 && !contains_comment(&snippet[open_pos..]),
759 fn format_impl_ref_and_type(
760 context: &RewriteContext,
763 ) -> Option<String> {
764 if let ast::ItemKind::Impl(
774 let mut result = String::with_capacity(128);
776 result.push_str(&format_visibility(&item.vis));
777 result.push_str(format_defaultness(defaultness));
778 result.push_str(format_unsafety(unsafety));
780 let lo = context.snippet_provider.span_after(item.span, "impl");
781 let hi = match *trait_ref {
782 Some(ref tr) => tr.path.span.lo(),
783 None => self_ty.span.lo(),
785 let shape = generics_shape_from_config(
787 Shape::indented(offset + last_line_width(&result), context.config),
790 let generics_str = rewrite_generics(context, "impl", generics, shape, mk_sp(lo, hi))?;
791 result.push_str(&generics_str);
793 let polarity_str = if polarity == ast::ImplPolarity::Negative {
799 if let Some(ref trait_ref) = *trait_ref {
800 let result_len = last_line_width(&result);
801 result.push_str(&rewrite_trait_ref(
810 // Try to put the self type in a single line.
812 let trait_ref_overhead = if trait_ref.is_some() { 4 } else { 0 };
813 let curly_brace_overhead = if generics.where_clause.predicates.is_empty() {
814 // If there is no where clause adapt budget for type formatting to take space and curly
815 // brace into account.
816 match context.config.brace_style() {
817 BraceStyle::AlwaysNextLine => 0,
823 let used_space = last_line_width(&result) + trait_ref_overhead + curly_brace_overhead;
824 // 1 = space before the type.
825 let budget = context.budget(used_space + 1);
826 if let Some(self_ty_str) = self_ty.rewrite(context, Shape::legacy(budget, offset)) {
827 if !self_ty_str.contains('\n') {
828 if trait_ref.is_some() {
829 result.push_str(" for ");
833 result.push_str(&self_ty_str);
838 // Couldn't fit the self type on a single line, put it on a new line.
840 // Add indentation of one additional tab.
841 let new_line_offset = offset.block_indent(context.config);
842 result.push_str(&new_line_offset.to_string(context.config));
843 if trait_ref.is_some() {
844 result.push_str("for ");
846 let budget = context.budget(last_line_width(&result));
847 let type_offset = match context.config.indent_style() {
848 IndentStyle::Visual => new_line_offset + trait_ref_overhead,
849 IndentStyle::Block => new_line_offset,
851 result.push_str(&*self_ty.rewrite(context, Shape::legacy(budget, type_offset))?);
858 fn rewrite_trait_ref(
859 context: &RewriteContext,
860 trait_ref: &ast::TraitRef,
864 ) -> Option<String> {
865 // 1 = space between generics and trait_ref
866 let used_space = 1 + polarity_str.len() + result_len;
867 let shape = Shape::indented(offset + used_space, context.config);
868 if let Some(trait_ref_str) = trait_ref.rewrite(context, shape) {
869 if !trait_ref_str.contains('\n') {
870 return Some(format!(" {}{}", polarity_str, &trait_ref_str));
873 // We could not make enough space for trait_ref, so put it on new line.
874 let offset = offset.block_indent(context.config);
875 let shape = Shape::indented(offset, context.config);
876 let trait_ref_str = trait_ref.rewrite(context, shape)?;
879 &offset.to_string_with_newline(context.config),
885 pub struct StructParts<'a> {
888 vis: &'a ast::Visibility,
889 def: &'a ast::VariantData,
890 generics: Option<&'a ast::Generics>,
894 impl<'a> StructParts<'a> {
895 fn format_header(&self) -> String {
896 format_header(self.prefix, self.ident, self.vis)
899 fn from_variant(variant: &'a ast::Variant) -> Self {
902 ident: variant.node.ident,
903 vis: &DEFAULT_VISIBILITY,
904 def: &variant.node.data,
910 pub fn from_item(item: &'a ast::Item) -> Self {
911 let (prefix, def, generics) = match item.node {
912 ast::ItemKind::Struct(ref def, ref generics) => ("struct ", def, generics),
913 ast::ItemKind::Union(ref def, ref generics) => ("union ", def, generics),
921 generics: Some(generics),
928 context: &RewriteContext,
929 struct_parts: &StructParts,
931 one_line_width: Option<usize>,
932 ) -> Option<String> {
933 match *struct_parts.def {
934 ast::VariantData::Unit(..) => format_unit_struct(context, struct_parts, offset),
935 ast::VariantData::Tuple(ref fields, _) => {
936 format_tuple_struct(context, struct_parts, fields, offset)
938 ast::VariantData::Struct(ref fields, _) => {
939 format_struct_struct(context, struct_parts, fields, offset, one_line_width)
944 pub fn format_trait(context: &RewriteContext, item: &ast::Item, offset: Indent) -> Option<String> {
945 if let ast::ItemKind::Trait(
949 ref type_param_bounds,
953 let mut result = String::with_capacity(128);
954 let header = format!(
956 format_auto(is_auto),
957 format_visibility(&item.vis),
958 format_unsafety(unsafety),
960 result.push_str(&header);
962 let body_lo = context.snippet_provider.span_after(item.span, "{");
964 let shape = Shape::indented(offset, context.config).offset_left(result.len())?;
965 let generics_str = rewrite_generics(
967 &item.ident.to_string(),
970 mk_sp(item.span.lo(), body_lo),
972 result.push_str(&generics_str);
974 // FIXME(#2055): rustfmt fails to format when there are comments between trait bounds.
975 if !type_param_bounds.is_empty() {
976 let ident_hi = context
978 .span_after(item.span, &format!("{}", item.ident));
979 let bound_hi = type_param_bounds.last().unwrap().span().hi();
980 let snippet = context.snippet(mk_sp(ident_hi, bound_hi));
981 if contains_comment(snippet) {
985 if !type_param_bounds.is_empty() {
986 result = rewrite_assign_rhs_with(
989 &TraitTyParamBounds::new(type_param_bounds),
991 RhsTactics::ForceNextLine,
995 // Rewrite where clause.
996 if !generics.where_clause.predicates.is_empty() {
997 let where_density = if context.config.indent_style() == IndentStyle::Block {
1003 let where_budget = context.budget(last_line_width(&result));
1004 let pos_before_where = if type_param_bounds.is_empty() {
1005 generics.where_clause.span.lo()
1007 type_param_bounds[type_param_bounds.len() - 1].span().hi()
1009 let option = WhereClauseOption::snuggled(&generics_str);
1010 let where_clause_str = rewrite_where_clause(
1012 &generics.where_clause,
1013 context.config.brace_style(),
1014 Shape::legacy(where_budget, offset.block_only()),
1022 // If the where clause cannot fit on the same line,
1023 // put the where clause on a new line
1024 if !where_clause_str.contains('\n')
1025 && last_line_width(&result) + where_clause_str.len() + offset.width()
1026 > context.config.comment_width()
1028 let width = offset.block_indent + context.config.tab_spaces() - 1;
1029 let where_indent = Indent::new(0, width);
1030 result.push_str(&where_indent.to_string_with_newline(context.config));
1032 result.push_str(&where_clause_str);
1034 let item_snippet = context.snippet(item.span);
1035 if let Some(lo) = item_snippet.find('/') {
1037 let comment_hi = body_lo - BytePos(1);
1038 let comment_lo = item.span.lo() + BytePos(lo as u32);
1039 if comment_lo < comment_hi {
1040 match recover_missing_comment_in_span(
1041 mk_sp(comment_lo, comment_hi),
1042 Shape::indented(offset, context.config),
1044 last_line_width(&result),
1046 Some(ref missing_comment) if !missing_comment.is_empty() => {
1047 result.push_str(missing_comment);
1055 match context.config.brace_style() {
1056 _ if last_line_contains_single_line_comment(&result)
1057 || last_line_width(&result) + 2 > context.budget(offset.width()) =>
1059 result.push_str(&offset.to_string_with_newline(context.config));
1061 BraceStyle::AlwaysNextLine => {
1062 result.push_str(&offset.to_string_with_newline(context.config));
1064 BraceStyle::PreferSameLine => result.push(' '),
1065 BraceStyle::SameLineWhere => {
1066 if result.contains('\n')
1067 || (!generics.where_clause.predicates.is_empty() && !trait_items.is_empty())
1069 result.push_str(&offset.to_string_with_newline(context.config));
1077 let snippet = context.snippet(item.span);
1078 let open_pos = snippet.find_uncommented("{")? + 1;
1080 if !trait_items.is_empty() || contains_comment(&snippet[open_pos..]) {
1081 let mut visitor = FmtVisitor::from_context(context);
1082 visitor.block_indent = offset.block_only().block_indent(context.config);
1083 visitor.last_pos = item.span.lo() + BytePos(open_pos as u32);
1085 for item in trait_items {
1086 visitor.visit_trait_item(item);
1089 visitor.format_missing(item.span.hi() - BytePos(1));
1091 let inner_indent_str = visitor.block_indent.to_string_with_newline(context.config);
1092 let outer_indent_str = offset.block_only().to_string_with_newline(context.config);
1094 result.push_str(&inner_indent_str);
1095 result.push_str(visitor.buffer.to_string().trim());
1096 result.push_str(&outer_indent_str);
1097 } else if result.contains('\n') {
1108 pub fn format_trait_alias(
1109 context: &RewriteContext,
1111 generics: &ast::Generics,
1112 ty_param_bounds: &ast::TyParamBounds,
1114 ) -> Option<String> {
1115 let alias = ident.name.as_str();
1116 // 6 = "trait ", 2 = " ="
1117 let g_shape = shape.offset_left(6)?.sub_width(2)?;
1118 let generics_str = rewrite_generics(context, &alias, generics, g_shape, generics.span)?;
1119 let lhs = format!("trait {} =", generics_str);
1121 rewrite_assign_rhs(context, lhs, ty_param_bounds, shape.sub_width(1)?).map(|s| s + ";")
1124 fn format_unit_struct(context: &RewriteContext, p: &StructParts, offset: Indent) -> Option<String> {
1125 let header_str = format_header(p.prefix, p.ident, p.vis);
1126 let generics_str = if let Some(generics) = p.generics {
1127 let hi = if generics.where_clause.predicates.is_empty() {
1130 generics.where_clause.span.hi()
1135 context.config.brace_style(),
1138 mk_sp(generics.span.lo(), hi),
1139 last_line_width(&header_str),
1144 Some(format!("{}{};", header_str, generics_str))
1147 pub fn format_struct_struct(
1148 context: &RewriteContext,
1149 struct_parts: &StructParts,
1150 fields: &[ast::StructField],
1152 one_line_width: Option<usize>,
1153 ) -> Option<String> {
1154 let mut result = String::with_capacity(1024);
1155 let span = struct_parts.span;
1157 let header_str = struct_parts.format_header();
1158 result.push_str(&header_str);
1160 let header_hi = span.lo() + BytePos(header_str.len() as u32);
1161 let body_lo = context.snippet_provider.span_after(span, "{");
1163 let generics_str = match struct_parts.generics {
1164 Some(g) => format_generics(
1167 context.config.brace_style(),
1168 if fields.is_empty() {
1169 BracePos::ForceSameLine
1174 mk_sp(header_hi, body_lo),
1175 last_line_width(&result),
1178 // 3 = ` {}`, 2 = ` {`.
1179 let overhead = if fields.is_empty() { 3 } else { 2 };
1180 if (context.config.brace_style() == BraceStyle::AlwaysNextLine && !fields.is_empty())
1181 || context.config.max_width() < overhead + result.len()
1183 format!("\n{}{{", offset.block_only().to_string(context.config))
1190 let overhead = if fields.is_empty() { 1 } else { 0 };
1191 let total_width = result.len() + generics_str.len() + overhead;
1192 if !generics_str.is_empty() && !generics_str.contains('\n')
1193 && total_width > context.config.max_width()
1196 result.push_str(&offset.to_string(context.config));
1197 result.push_str(generics_str.trim_left());
1199 result.push_str(&generics_str);
1202 if fields.is_empty() {
1203 let inner_span = mk_sp(body_lo, span.hi() - BytePos(1));
1204 format_empty_struct_or_tuple(context, inner_span, offset, &mut result, "", "}");
1205 return Some(result);
1209 let one_line_budget = context.budget(result.len() + 3 + offset.width());
1210 let one_line_budget =
1211 one_line_width.map_or(0, |one_line_width| min(one_line_width, one_line_budget));
1213 let items_str = rewrite_with_alignment(
1216 Shape::indented(offset, context.config).sub_width(1)?,
1217 mk_sp(body_lo, span.hi()),
1221 if !items_str.contains('\n') && !result.contains('\n') && items_str.len() <= one_line_budget
1222 && !last_line_contains_single_line_comment(&items_str)
1224 Some(format!("{} {} }}", result, items_str))
1230 .block_indent(context.config)
1231 .to_string(context.config),
1233 offset.to_string(context.config)
1238 fn get_bytepos_after_visibility(vis: &ast::Visibility, default_span: Span) -> BytePos {
1240 ast::VisibilityKind::Crate(..) | ast::VisibilityKind::Restricted { .. } => vis.span.hi(),
1241 _ => default_span.lo(),
1245 // Format tuple or struct without any fields. We need to make sure that the comments
1246 // inside the delimiters are preserved.
1247 fn format_empty_struct_or_tuple(
1248 context: &RewriteContext,
1251 result: &mut String,
1255 // 3 = " {}" or "();"
1256 let used_width = last_line_used_width(&result, offset.width()) + 3;
1257 if used_width > context.config.max_width() {
1258 result.push_str(&offset.to_string_with_newline(context.config))
1260 result.push_str(opener);
1261 match rewrite_missing_comment(span, Shape::indented(offset, context.config), context) {
1262 Some(ref s) if s.is_empty() => (),
1264 if !is_single_line(s) || first_line_contains_single_line_comment(s) {
1265 let nested_indent_str = offset
1266 .block_indent(context.config)
1267 .to_string_with_newline(context.config);
1268 result.push_str(&nested_indent_str);
1271 if last_line_contains_single_line_comment(s) {
1272 result.push_str(&offset.to_string_with_newline(context.config));
1275 None => result.push_str(context.snippet(span)),
1277 result.push_str(closer);
1280 fn format_tuple_struct(
1281 context: &RewriteContext,
1282 struct_parts: &StructParts,
1283 fields: &[ast::StructField],
1285 ) -> Option<String> {
1286 let mut result = String::with_capacity(1024);
1287 let span = struct_parts.span;
1289 let header_str = struct_parts.format_header();
1290 result.push_str(&header_str);
1292 let body_lo = if fields.is_empty() {
1293 let lo = get_bytepos_after_visibility(struct_parts.vis, span);
1296 .span_after(mk_sp(lo, span.hi()), "(")
1300 let body_hi = if fields.is_empty() {
1303 .span_after(mk_sp(body_lo, span.hi()), ")")
1305 // This is a dirty hack to work around a missing `)` from the span of the last field.
1306 let last_arg_span = fields[fields.len() - 1].span;
1307 if context.snippet(last_arg_span).ends_with(')') {
1312 .span_after(mk_sp(last_arg_span.hi(), span.hi()), ")")
1316 let where_clause_str = match struct_parts.generics {
1318 let budget = context.budget(last_line_width(&header_str));
1319 let shape = Shape::legacy(budget, offset);
1320 let g_span = mk_sp(span.lo(), body_lo);
1321 let generics_str = rewrite_generics(context, "", generics, shape, g_span)?;
1322 result.push_str(&generics_str);
1324 let where_budget = context.budget(last_line_width(&result));
1325 let option = WhereClauseOption::new(true, false);
1326 rewrite_where_clause(
1328 &generics.where_clause,
1329 context.config.brace_style(),
1330 Shape::legacy(where_budget, offset.block_only()),
1331 Density::Compressed,
1339 None => "".to_owned(),
1342 if fields.is_empty() {
1343 let body_hi = context
1345 .span_before(mk_sp(body_lo, span.hi()), ")");
1346 let inner_span = mk_sp(body_lo, body_hi);
1347 format_empty_struct_or_tuple(context, inner_span, offset, &mut result, "(", ")");
1349 let shape = Shape::indented(offset, context.config).sub_width(1)?;
1350 let fields = &fields.iter().collect::<Vec<_>>();
1351 result = overflow::rewrite_with_parens(
1357 context.config.width_heuristics().fn_call_width,
1362 if !where_clause_str.is_empty() && !where_clause_str.contains('\n')
1363 && (result.contains('\n')
1364 || offset.block_indent + result.len() + where_clause_str.len() + 1
1365 > context.config.max_width())
1367 // We need to put the where clause on a new line, but we didn't
1368 // know that earlier, so the where clause will not be indented properly.
1371 .push_str(&(offset.block_only() + (context.config.tab_spaces() - 1))
1372 .to_string(context.config));
1374 result.push_str(&where_clause_str);
1379 pub fn rewrite_type_alias(
1380 context: &RewriteContext,
1384 generics: &ast::Generics,
1385 vis: &ast::Visibility,
1387 ) -> Option<String> {
1388 let mut result = String::with_capacity(128);
1390 result.push_str(&format_visibility(vis));
1391 result.push_str("type ");
1394 let g_shape = Shape::indented(indent, context.config)
1395 .offset_left(result.len())?
1398 context.snippet_provider.span_after(span, "type"),
1401 let generics_str = rewrite_generics(context, &ident.to_string(), generics, g_shape, g_span)?;
1402 result.push_str(&generics_str);
1404 let where_budget = context.budget(last_line_width(&result));
1405 let option = WhereClauseOption::snuggled(&result);
1406 let where_clause_str = rewrite_where_clause(
1408 &generics.where_clause,
1409 context.config.brace_style(),
1410 Shape::legacy(where_budget, indent),
1418 result.push_str(&where_clause_str);
1419 if where_clause_str.is_empty() {
1420 result.push_str(" =");
1422 result.push_str(&format!(
1424 indent.to_string_with_newline(context.config)
1429 let ty_shape = Shape::indented(indent, context.config).sub_width(1)?;
1430 rewrite_assign_rhs(context, result, ty, ty_shape).map(|s| s + ";")
1433 fn type_annotation_spacing(config: &Config) -> (&str, &str) {
1435 if config.space_before_colon() { " " } else { "" },
1436 if config.space_after_colon() { " " } else { "" },
1440 pub fn rewrite_struct_field_prefix(
1441 context: &RewriteContext,
1442 field: &ast::StructField,
1443 ) -> Option<String> {
1444 let vis = format_visibility(&field.vis);
1445 let type_annotation_spacing = type_annotation_spacing(context.config);
1446 Some(match field.ident {
1447 Some(name) => format!("{}{}{}:", vis, name, type_annotation_spacing.0),
1448 None => format!("{}", vis),
1452 impl Rewrite for ast::StructField {
1453 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
1454 rewrite_struct_field(context, self, shape, 0)
1458 pub fn rewrite_struct_field(
1459 context: &RewriteContext,
1460 field: &ast::StructField,
1462 lhs_max_width: usize,
1463 ) -> Option<String> {
1464 if contains_skip(&field.attrs) {
1465 return Some(context.snippet(field.span()).to_owned());
1468 let type_annotation_spacing = type_annotation_spacing(context.config);
1469 let prefix = rewrite_struct_field_prefix(context, field)?;
1471 let attrs_str = field.attrs.rewrite(context, shape)?;
1472 let attrs_extendable = field.ident.is_none() && is_attributes_extendable(&attrs_str);
1473 let missing_span = if field.attrs.is_empty() {
1474 mk_sp(field.span.lo(), field.span.lo())
1476 mk_sp(field.attrs.last().unwrap().span.hi(), field.span.lo())
1478 let mut spacing = String::from(if field.ident.is_some() {
1479 type_annotation_spacing.1
1483 // Try to put everything on a single line.
1484 let attr_prefix = combine_strs_with_missing_comments(
1492 let overhead = last_line_width(&attr_prefix);
1493 let lhs_offset = lhs_max_width.checked_sub(overhead).unwrap_or(0);
1494 for _ in 0..lhs_offset {
1497 // In this extreme case we will be missing a space betweeen an attribute and a field.
1498 if prefix.is_empty() && !attrs_str.is_empty() && attrs_extendable && spacing.is_empty() {
1502 .offset_left(overhead + spacing.len())
1503 .and_then(|ty_shape| field.ty.rewrite(context, ty_shape));
1504 if let Some(ref ty) = orig_ty {
1505 if !ty.contains('\n') {
1506 return Some(attr_prefix + &spacing + ty);
1510 let is_prefix_empty = prefix.is_empty();
1511 // We must use multiline. We are going to put attributes and a field on different lines.
1512 let field_str = rewrite_assign_rhs(context, prefix, &*field.ty, shape)?;
1513 // Remove a leading white-space from `rewrite_assign_rhs()` when rewriting a tuple struct.
1514 let field_str = if is_prefix_empty {
1515 field_str.trim_left()
1519 combine_strs_with_missing_comments(context, &attrs_str, field_str, missing_span, shape, false)
1522 pub struct StaticParts<'a> {
1524 vis: &'a ast::Visibility,
1527 mutability: ast::Mutability,
1528 expr_opt: Option<&'a ptr::P<ast::Expr>>,
1529 defaultness: Option<ast::Defaultness>,
1533 impl<'a> StaticParts<'a> {
1534 pub fn from_item(item: &'a ast::Item) -> Self {
1535 let (prefix, ty, mutability, expr) = match item.node {
1536 ast::ItemKind::Static(ref ty, mutability, ref expr) => ("static", ty, mutability, expr),
1537 ast::ItemKind::Const(ref ty, ref expr) => {
1538 ("const", ty, ast::Mutability::Immutable, expr)
1540 _ => unreachable!(),
1548 expr_opt: Some(expr),
1554 pub fn from_trait_item(ti: &'a ast::TraitItem) -> Self {
1555 let (ty, expr_opt) = match ti.node {
1556 ast::TraitItemKind::Const(ref ty, ref expr_opt) => (ty, expr_opt),
1557 _ => unreachable!(),
1561 vis: &DEFAULT_VISIBILITY,
1564 mutability: ast::Mutability::Immutable,
1565 expr_opt: expr_opt.as_ref(),
1571 pub fn from_impl_item(ii: &'a ast::ImplItem) -> Self {
1572 let (ty, expr) = match ii.node {
1573 ast::ImplItemKind::Const(ref ty, ref expr) => (ty, expr),
1574 _ => unreachable!(),
1581 mutability: ast::Mutability::Immutable,
1582 expr_opt: Some(expr),
1583 defaultness: Some(ii.defaultness),
1590 context: &RewriteContext,
1591 static_parts: &StaticParts,
1593 ) -> Option<String> {
1594 let colon = colon_spaces(
1595 context.config.space_before_colon(),
1596 context.config.space_after_colon(),
1598 let mut prefix = format!(
1600 format_visibility(static_parts.vis),
1601 static_parts.defaultness.map_or("", format_defaultness),
1602 static_parts.prefix,
1603 format_mutability(static_parts.mutability),
1609 Shape::indented(offset.block_only(), context.config).offset_left(prefix.len() + 2)?;
1610 let ty_str = match static_parts.ty.rewrite(context, ty_shape) {
1611 Some(ty_str) => ty_str,
1613 if prefix.ends_with(' ') {
1616 let nested_indent = offset.block_indent(context.config);
1617 let nested_shape = Shape::indented(nested_indent, context.config);
1618 let ty_str = static_parts.ty.rewrite(context, nested_shape)?;
1621 nested_indent.to_string_with_newline(context.config),
1627 if let Some(expr) = static_parts.expr_opt {
1628 let lhs = format!("{}{} =", prefix, ty_str);
1630 let remaining_width = context.budget(offset.block_indent + 1);
1635 Shape::legacy(remaining_width, offset.block_only()),
1636 ).and_then(|res| recover_comment_removed(res, static_parts.span, context))
1637 .map(|s| if s.ends_with(';') { s } else { s + ";" })
1639 Some(format!("{}{};", prefix, ty_str))
1643 pub fn rewrite_associated_type(
1645 ty_opt: Option<&ptr::P<ast::Ty>>,
1646 ty_param_bounds_opt: Option<&ast::TyParamBounds>,
1647 context: &RewriteContext,
1649 ) -> Option<String> {
1650 let prefix = format!("type {}", ident);
1652 let type_bounds_str = if let Some(bounds) = ty_param_bounds_opt {
1653 if bounds.is_empty() {
1657 let shape = Shape::indented(indent, context.config).offset_left(prefix.len() + 2)?;
1658 bounds.rewrite(context, shape).map(|s| format!(": {}", s))?
1664 if let Some(ty) = ty_opt {
1666 let shape = Shape::indented(indent, context.config).sub_width(1)?;
1667 let lhs = format!("{}{} =", prefix, type_bounds_str);
1668 rewrite_assign_rhs(context, lhs, &**ty, shape).map(|s| s + ";")
1670 Some(format!("{}{};", prefix, type_bounds_str))
1674 pub fn rewrite_associated_impl_type(
1676 defaultness: ast::Defaultness,
1677 ty_opt: Option<&ptr::P<ast::Ty>>,
1678 ty_param_bounds_opt: Option<&ast::TyParamBounds>,
1679 context: &RewriteContext,
1681 ) -> Option<String> {
1682 let result = rewrite_associated_type(ident, ty_opt, ty_param_bounds_opt, context, indent)?;
1685 ast::Defaultness::Default => Some(format!("default {}", result)),
1690 impl Rewrite for ast::FunctionRetTy {
1691 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
1693 ast::FunctionRetTy::Default(_) => Some(String::new()),
1694 ast::FunctionRetTy::Ty(ref ty) => {
1695 let inner_width = shape.width.checked_sub(3)?;
1696 ty.rewrite(context, Shape::legacy(inner_width, shape.indent + 3))
1697 .map(|r| format!("-> {}", r))
1703 fn is_empty_infer(context: &RewriteContext, ty: &ast::Ty) -> bool {
1705 ast::TyKind::Infer => {
1706 let original = context.snippet(ty.span);
1713 impl Rewrite for ast::Arg {
1714 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
1715 if is_named_arg(self) {
1716 let mut result = self.pat
1717 .rewrite(context, Shape::legacy(shape.width, shape.indent))?;
1719 if !is_empty_infer(context, &*self.ty) {
1720 if context.config.space_before_colon() {
1721 result.push_str(" ");
1723 result.push_str(":");
1724 if context.config.space_after_colon() {
1725 result.push_str(" ");
1727 let overhead = last_line_width(&result);
1728 let max_width = shape.width.checked_sub(overhead)?;
1729 let ty_str = self.ty
1730 .rewrite(context, Shape::legacy(max_width, shape.indent))?;
1731 result.push_str(&ty_str);
1736 self.ty.rewrite(context, shape)
1741 fn rewrite_explicit_self(
1742 explicit_self: &ast::ExplicitSelf,
1744 context: &RewriteContext,
1745 ) -> Option<String> {
1746 match explicit_self.node {
1747 ast::SelfKind::Region(lt, m) => {
1748 let mut_str = format_mutability(m);
1751 let lifetime_str = l.rewrite(
1753 Shape::legacy(context.config.max_width(), Indent::empty()),
1755 Some(format!("&{} {}self", lifetime_str, mut_str))
1757 None => Some(format!("&{}self", mut_str)),
1760 ast::SelfKind::Explicit(ref ty, _) => {
1761 assert!(!args.is_empty(), "&[ast::Arg] shouldn't be empty.");
1763 let mutability = explicit_self_mutability(&args[0]);
1764 let type_str = ty.rewrite(
1766 Shape::legacy(context.config.max_width(), Indent::empty()),
1771 format_mutability(mutability),
1775 ast::SelfKind::Value(_) => {
1776 assert!(!args.is_empty(), "&[ast::Arg] shouldn't be empty.");
1778 let mutability = explicit_self_mutability(&args[0]);
1780 Some(format!("{}self", format_mutability(mutability)))
1785 // Hacky solution caused by absence of `Mutability` in `SelfValue` and
1786 // `SelfExplicit` variants of `ast::ExplicitSelf_`.
1787 fn explicit_self_mutability(arg: &ast::Arg) -> ast::Mutability {
1788 if let ast::PatKind::Ident(ast::BindingMode::ByValue(mutability), _, _) = arg.pat.node {
1795 pub fn span_lo_for_arg(arg: &ast::Arg) -> BytePos {
1796 if is_named_arg(arg) {
1803 pub fn span_hi_for_arg(context: &RewriteContext, arg: &ast::Arg) -> BytePos {
1805 ast::TyKind::Infer if context.snippet(arg.ty.span) == "_" => arg.ty.span.hi(),
1806 ast::TyKind::Infer if is_named_arg(arg) => arg.pat.span.hi(),
1807 _ => arg.ty.span.hi(),
1811 pub fn is_named_arg(arg: &ast::Arg) -> bool {
1812 if let ast::PatKind::Ident(_, ident, _) = arg.pat.node {
1813 ident != symbol::keywords::Invalid.ident()
1819 // Return type is (result, force_new_line_for_brace)
1821 context: &RewriteContext,
1826 newline_brace: bool,
1828 ) -> Option<(String, bool)> {
1829 let mut force_new_line_for_brace = false;
1831 let where_clause = &fn_sig.generics.where_clause;
1833 let mut result = String::with_capacity(1024);
1834 result.push_str(&fn_sig.to_str(context));
1837 result.push_str("fn ");
1840 let overhead = if has_body && !newline_brace {
1847 let used_width = last_line_used_width(&result, indent.width());
1848 let one_line_budget = context.budget(used_width + overhead);
1850 width: one_line_budget,
1854 let fd = fn_sig.decl;
1855 let g_span = mk_sp(span.lo(), fd.output.span().lo());
1857 rewrite_generics(context, &ident.to_string(), fn_sig.generics, shape, g_span)?;
1858 result.push_str(&generics_str);
1860 let snuggle_angle_bracket = generics_str
1863 .map_or(false, |l| l.trim_left().len() == 1);
1865 // Note that the width and indent don't really matter, we'll re-layout the
1866 // return type later anyway.
1867 let ret_str = fd.output
1868 .rewrite(context, Shape::indented(indent, context.config))?;
1870 let multi_line_ret_str = ret_str.contains('\n');
1871 let ret_str_len = if multi_line_ret_str { 0 } else { ret_str.len() };
1874 let (one_line_budget, multi_line_budget, mut arg_indent) = compute_budgets_for_args(
1885 "rewrite_fn_base: one_line_budget: {}, multi_line_budget: {}, arg_indent: {:?}",
1886 one_line_budget, multi_line_budget, arg_indent
1889 // Check if vertical layout was forced.
1890 if one_line_budget == 0 {
1891 if snuggle_angle_bracket {
1894 result.push_str("(");
1895 if context.config.indent_style() == IndentStyle::Visual {
1896 result.push_str(&arg_indent.to_string_with_newline(context.config));
1902 if context.config.spaces_within_parens_and_brackets() && !fd.inputs.is_empty()
1903 && result.ends_with('(')
1908 // Skip `pub(crate)`.
1909 let lo_after_visibility = get_bytepos_after_visibility(&fn_sig.visibility, span);
1910 // A conservative estimation, to goal is to be over all parens in generics
1911 let args_start = fn_sig
1916 .map_or(lo_after_visibility, |param| param.span().hi());
1917 let args_end = if fd.inputs.is_empty() {
1920 .span_after(mk_sp(args_start, span.hi()), ")")
1922 let last_span = mk_sp(fd.inputs[fd.inputs.len() - 1].span().hi(), span.hi());
1923 context.snippet_provider.span_after(last_span, ")")
1925 let args_span = mk_sp(
1928 .span_after(mk_sp(args_start, span.hi()), "("),
1931 let arg_str = rewrite_args(
1934 fd.get_self().as_ref(),
1941 generics_str.contains('\n'),
1944 let put_args_in_block = match context.config.indent_style() {
1945 IndentStyle::Block => arg_str.contains('\n') || arg_str.len() > one_line_budget,
1947 } && !fd.inputs.is_empty();
1949 let mut args_last_line_contains_comment = false;
1950 if put_args_in_block {
1951 arg_indent = indent.block_indent(context.config);
1952 result.push_str(&arg_indent.to_string_with_newline(context.config));
1953 result.push_str(&arg_str);
1954 result.push_str(&indent.to_string_with_newline(context.config));
1957 result.push_str(&arg_str);
1958 let used_width = last_line_used_width(&result, indent.width()) + first_line_width(&ret_str);
1959 // Put the closing brace on the next line if it overflows the max width.
1961 if fd.inputs.is_empty() && used_width + 1 > context.config.max_width() {
1964 if context.config.spaces_within_parens_and_brackets() && !fd.inputs.is_empty() {
1967 // If the last line of args contains comment, we cannot put the closing paren
1968 // on the same line.
1972 .map_or(false, |last_line| last_line.contains("//"))
1974 args_last_line_contains_comment = true;
1975 result.push_str(&arg_indent.to_string_with_newline(context.config));
1981 if let ast::FunctionRetTy::Ty(..) = fd.output {
1982 let ret_should_indent = match context.config.indent_style() {
1983 // If our args are block layout then we surely must have space.
1984 IndentStyle::Block if put_args_in_block || fd.inputs.is_empty() => false,
1985 _ if args_last_line_contains_comment => false,
1986 _ if result.contains('\n') || multi_line_ret_str => true,
1988 // If the return type would push over the max width, then put the return type on
1989 // a new line. With the +1 for the signature length an additional space between
1990 // the closing parenthesis of the argument and the arrow '->' is considered.
1991 let mut sig_length = result.len() + indent.width() + ret_str_len + 1;
1993 // If there is no where clause, take into account the space after the return type
1995 if where_clause.predicates.is_empty() {
1999 sig_length > context.config.max_width()
2002 let ret_indent = if ret_should_indent {
2003 let indent = if arg_str.is_empty() {
2004 // Aligning with non-existent args looks silly.
2005 force_new_line_for_brace = true;
2008 // FIXME: we might want to check that using the arg indent
2009 // doesn't blow our budget, and if it does, then fallback to
2010 // the where clause indent.
2014 result.push_str(&indent.to_string_with_newline(context.config));
2018 Indent::new(indent.block_indent, last_line_width(&result))
2021 if multi_line_ret_str || ret_should_indent {
2022 // Now that we know the proper indent and width, we need to
2023 // re-layout the return type.
2024 let ret_str = fd.output
2025 .rewrite(context, Shape::indented(ret_indent, context.config))?;
2026 result.push_str(&ret_str);
2028 result.push_str(&ret_str);
2031 // Comment between return type and the end of the decl.
2032 let snippet_lo = fd.output.span().hi();
2033 if where_clause.predicates.is_empty() {
2034 let snippet_hi = span.hi();
2035 let snippet = context.snippet(mk_sp(snippet_lo, snippet_hi));
2036 // Try to preserve the layout of the original snippet.
2037 let original_starts_with_newline = snippet
2039 .map_or(false, |i| starts_with_newline(&snippet[i..]));
2040 let original_ends_with_newline = snippet
2041 .rfind(|c| c != ' ')
2042 .map_or(false, |i| snippet[i..].ends_with('\n'));
2043 let snippet = snippet.trim();
2044 if !snippet.is_empty() {
2045 result.push(if original_starts_with_newline {
2050 result.push_str(snippet);
2051 if original_ends_with_newline {
2052 force_new_line_for_brace = true;
2058 let pos_before_where = match fd.output {
2059 ast::FunctionRetTy::Default(..) => args_span.hi(),
2060 ast::FunctionRetTy::Ty(ref ty) => ty.span.hi(),
2063 let is_args_multi_lined = arg_str.contains('\n');
2065 let option = WhereClauseOption::new(!has_body, put_args_in_block && ret_str.is_empty());
2066 let where_clause_str = rewrite_where_clause(
2069 context.config.brace_style(),
2070 Shape::indented(indent, context.config),
2076 is_args_multi_lined,
2078 // If there are neither where clause nor return type, we may be missing comments between
2080 if where_clause_str.is_empty() {
2081 if let ast::FunctionRetTy::Default(ret_span) = fd.output {
2082 match recover_missing_comment_in_span(
2083 mk_sp(args_span.hi(), ret_span.hi()),
2086 last_line_width(&result),
2088 Some(ref missing_comment) if !missing_comment.is_empty() => {
2089 result.push_str(missing_comment);
2090 force_new_line_for_brace = true;
2097 result.push_str(&where_clause_str);
2099 force_new_line_for_brace |= last_line_contains_single_line_comment(&result);
2100 force_new_line_for_brace |= is_args_multi_lined && context.config.where_single_line();
2101 Some((result, force_new_line_for_brace))
2104 #[derive(Copy, Clone)]
2105 struct WhereClauseOption {
2106 suppress_comma: bool, // Force no trailing comma
2107 snuggle: bool, // Do not insert newline before `where`
2108 compress_where: bool, // Try single line where clause instead of vertical layout
2111 impl WhereClauseOption {
2112 pub fn new(suppress_comma: bool, snuggle: bool) -> WhereClauseOption {
2116 compress_where: false,
2120 pub fn snuggled(current: &str) -> WhereClauseOption {
2122 suppress_comma: false,
2123 snuggle: trimmed_last_line_width(current) == 1,
2124 compress_where: false,
2130 context: &RewriteContext,
2132 explicit_self: Option<&ast::ExplicitSelf>,
2133 one_line_budget: usize,
2134 multi_line_budget: usize,
2139 generics_str_contains_newline: bool,
2140 ) -> Option<String> {
2141 let mut arg_item_strs = args.iter()
2142 .map(|arg| arg.rewrite(context, Shape::legacy(multi_line_budget, arg_indent)))
2143 .collect::<Option<Vec<_>>>()?;
2145 // Account for sugary self.
2146 // FIXME: the comment for the self argument is dropped. This is blocked
2147 // on rust issue #27522.
2148 let min_args = explicit_self
2149 .and_then(|explicit_self| rewrite_explicit_self(explicit_self, args, context))
2150 .map_or(1, |self_str| {
2151 arg_item_strs[0] = self_str;
2155 // Comments between args.
2156 let mut arg_items = Vec::new();
2158 arg_items.push(ListItem::from_str(""));
2161 // FIXME(#21): if there are no args, there might still be a comment, but
2162 // without spans for the comment or parens, there is no chance of
2163 // getting it right. You also don't get to put a comment on self, unless
2165 if args.len() >= min_args || variadic {
2166 let comment_span_start = if min_args == 2 {
2167 let second_arg_start = if arg_has_pattern(&args[1]) {
2168 args[1].pat.span.lo()
2170 args[1].ty.span.lo()
2172 let reduced_span = mk_sp(span.lo(), second_arg_start);
2174 context.snippet_provider.span_after_last(reduced_span, ",")
2179 enum ArgumentKind<'a> {
2180 Regular(&'a ast::Arg),
2184 let variadic_arg = if variadic {
2185 let variadic_span = mk_sp(args.last().unwrap().ty.span.hi(), span.hi());
2186 let variadic_start =
2187 context.snippet_provider.span_after(variadic_span, "...") - BytePos(3);
2188 Some(ArgumentKind::Variadic(variadic_start))
2193 let more_items = itemize_list(
2194 context.snippet_provider,
2195 args[min_args - 1..]
2197 .map(ArgumentKind::Regular)
2198 .chain(variadic_arg),
2202 ArgumentKind::Regular(arg) => span_lo_for_arg(arg),
2203 ArgumentKind::Variadic(start) => start,
2206 ArgumentKind::Regular(arg) => arg.ty.span.hi(),
2207 ArgumentKind::Variadic(start) => start + BytePos(3),
2210 ArgumentKind::Regular(..) => None,
2211 ArgumentKind::Variadic(..) => Some("...".to_owned()),
2218 arg_items.extend(more_items);
2221 let fits_in_one_line = !generics_str_contains_newline
2222 && (arg_items.is_empty()
2223 || arg_items.len() == 1 && arg_item_strs[0].len() <= one_line_budget);
2225 for (item, arg) in arg_items.iter_mut().zip(arg_item_strs) {
2226 item.item = Some(arg);
2229 let last_line_ends_with_comment = arg_items
2232 .and_then(|item| item.post_comment.as_ref())
2233 .map_or(false, |s| s.trim().starts_with("//"));
2235 let (indent, trailing_comma) = match context.config.indent_style() {
2236 IndentStyle::Block if fits_in_one_line => {
2237 (indent.block_indent(context.config), SeparatorTactic::Never)
2239 IndentStyle::Block => (
2240 indent.block_indent(context.config),
2241 context.config.trailing_comma(),
2243 IndentStyle::Visual if last_line_ends_with_comment => {
2244 (arg_indent, context.config.trailing_comma())
2246 IndentStyle::Visual => (arg_indent, SeparatorTactic::Never),
2249 let tactic = definitive_tactic(
2251 context.config.fn_args_density().to_list_tactic(),
2255 let budget = match tactic {
2256 DefinitiveListTactic::Horizontal => one_line_budget,
2257 _ => multi_line_budget,
2260 debug!("rewrite_args: budget: {}, tactic: {:?}", budget, tactic);
2262 let fmt = ListFormatting {
2265 trailing_separator: if variadic {
2266 SeparatorTactic::Never
2270 separator_place: SeparatorPlace::Back,
2271 shape: Shape::legacy(budget, indent),
2272 ends_with_newline: tactic.ends_with_newline(context.config.indent_style()),
2273 preserve_newline: true,
2274 config: context.config,
2277 write_list(&arg_items, &fmt)
2280 fn arg_has_pattern(arg: &ast::Arg) -> bool {
2281 if let ast::PatKind::Ident(_, ident, _) = arg.pat.node {
2282 ident != symbol::keywords::Invalid.ident()
2288 fn compute_budgets_for_args(
2289 context: &RewriteContext,
2293 newline_brace: bool,
2295 force_vertical_layout: bool,
2296 ) -> Option<((usize, usize, Indent))> {
2298 "compute_budgets_for_args {} {:?}, {}, {}",
2304 // Try keeping everything on the same line.
2305 if !result.contains('\n') && !force_vertical_layout {
2306 // 2 = `()`, 3 = `() `, space is before ret_string.
2307 let overhead = if ret_str_len == 0 { 2 } else { 3 };
2308 let mut used_space = indent.width() + result.len() + ret_str_len + overhead;
2318 let one_line_budget = context.budget(used_space);
2320 if one_line_budget > 0 {
2322 let (indent, multi_line_budget) = match context.config.indent_style() {
2323 IndentStyle::Block => {
2324 let indent = indent.block_indent(context.config);
2325 (indent, context.budget(indent.width() + 1))
2327 IndentStyle::Visual => {
2328 let indent = indent + result.len() + 1;
2329 let multi_line_overhead = indent.width() + if newline_brace { 2 } else { 4 };
2330 (indent, context.budget(multi_line_overhead))
2334 return Some((one_line_budget, multi_line_budget, indent));
2338 // Didn't work. we must force vertical layout and put args on a newline.
2339 let new_indent = indent.block_indent(context.config);
2340 let used_space = match context.config.indent_style() {
2342 IndentStyle::Block => new_indent.width() + 1,
2343 // Account for `)` and possibly ` {`.
2344 IndentStyle::Visual => new_indent.width() + if ret_str_len == 0 { 1 } else { 3 },
2346 Some((0, context.budget(used_space), new_indent))
2349 fn newline_for_brace(config: &Config, where_clause: &ast::WhereClause) -> bool {
2350 let predicate_count = where_clause.predicates.len();
2352 if config.where_single_line() && predicate_count == 1 {
2355 let brace_style = config.brace_style();
2357 brace_style == BraceStyle::AlwaysNextLine
2358 || (brace_style == BraceStyle::SameLineWhere && predicate_count > 0)
2361 fn rewrite_generics(
2362 context: &RewriteContext,
2364 generics: &ast::Generics,
2367 ) -> Option<String> {
2368 // FIXME: convert bounds to where clauses where they get too big or if
2369 // there is a where clause at all.
2371 if generics.params.is_empty() {
2372 return Some(ident.to_owned());
2375 let params = &generics.params.iter().map(|e| &*e).collect::<Vec<_>>();
2376 overflow::rewrite_with_angle_brackets(context, ident, params, shape, span)
2379 pub fn generics_shape_from_config(config: &Config, shape: Shape, offset: usize) -> Option<Shape> {
2380 match config.indent_style() {
2381 IndentStyle::Visual => shape.visual_indent(1 + offset).sub_width(offset + 2),
2382 IndentStyle::Block => {
2386 .block_indent(config.tab_spaces())
2387 .with_max_width(config)
2393 fn rewrite_where_clause_rfc_style(
2394 context: &RewriteContext,
2395 where_clause: &ast::WhereClause,
2398 span_end: Option<BytePos>,
2399 span_end_before_where: BytePos,
2400 where_clause_option: WhereClauseOption,
2401 is_args_multi_line: bool,
2402 ) -> Option<String> {
2403 let block_shape = shape.block().with_max_width(context.config);
2405 let (span_before, span_after) =
2406 missing_span_before_after_where(span_end_before_where, where_clause);
2407 let (comment_before, comment_after) =
2408 rewrite_comments_before_after_where(context, span_before, span_after, shape)?;
2410 let starting_newline = if where_clause_option.snuggle && comment_before.is_empty() {
2413 block_shape.indent.to_string_with_newline(context.config)
2416 let clause_shape = block_shape.block_left(context.config.tab_spaces())?;
2418 let clause_shape = clause_shape.sub_width(1)?;
2419 // each clause on one line, trailing comma (except if suppress_comma)
2420 let span_start = where_clause.predicates[0].span().lo();
2421 // If we don't have the start of the next span, then use the end of the
2422 // predicates, but that means we miss comments.
2423 let len = where_clause.predicates.len();
2424 let end_of_preds = where_clause.predicates[len - 1].span().hi();
2425 let span_end = span_end.unwrap_or(end_of_preds);
2426 let items = itemize_list(
2427 context.snippet_provider,
2428 where_clause.predicates.iter(),
2431 |pred| pred.span().lo(),
2432 |pred| pred.span().hi(),
2433 |pred| pred.rewrite(context, clause_shape),
2438 let where_single_line = context.config.where_single_line() && len == 1 && !is_args_multi_line;
2439 let comma_tactic = if where_clause_option.suppress_comma || where_single_line {
2440 SeparatorTactic::Never
2442 context.config.trailing_comma()
2445 // shape should be vertical only and only if we have `where_single_line` option enabled
2446 // and the number of items of the where clause is equal to 1
2447 let shape_tactic = if where_single_line {
2448 DefinitiveListTactic::Horizontal
2450 DefinitiveListTactic::Vertical
2453 let fmt = ListFormatting {
2454 tactic: shape_tactic,
2456 trailing_separator: comma_tactic,
2457 separator_place: SeparatorPlace::Back,
2458 shape: clause_shape,
2459 ends_with_newline: true,
2460 preserve_newline: true,
2461 config: context.config,
2463 let preds_str = write_list(&items.collect::<Vec<_>>(), &fmt)?;
2465 let comment_separator = |comment: &str, shape: Shape| {
2466 if comment.is_empty() {
2469 shape.indent.to_string_with_newline(context.config)
2472 let newline_before_where = comment_separator(&comment_before, shape);
2473 let newline_after_where = comment_separator(&comment_after, clause_shape);
2476 let clause_sep = if where_clause_option.compress_where && comment_before.is_empty()
2477 && comment_after.is_empty() && !preds_str.contains('\n')
2478 && 6 + preds_str.len() <= shape.width || where_single_line
2482 clause_shape.indent.to_string_with_newline(context.config)
2485 "{}{}{}where{}{}{}{}",
2488 newline_before_where,
2489 newline_after_where,
2496 fn rewrite_where_clause(
2497 context: &RewriteContext,
2498 where_clause: &ast::WhereClause,
2499 brace_style: BraceStyle,
2503 span_end: Option<BytePos>,
2504 span_end_before_where: BytePos,
2505 where_clause_option: WhereClauseOption,
2506 is_args_multi_line: bool,
2507 ) -> Option<String> {
2508 if where_clause.predicates.is_empty() {
2509 return Some(String::new());
2512 if context.config.indent_style() == IndentStyle::Block {
2513 return rewrite_where_clause_rfc_style(
2519 span_end_before_where,
2520 where_clause_option,
2525 let extra_indent = Indent::new(context.config.tab_spaces(), 0);
2527 let offset = match context.config.indent_style() {
2528 IndentStyle::Block => shape.indent + extra_indent.block_indent(context.config),
2529 // 6 = "where ".len()
2530 IndentStyle::Visual => shape.indent + extra_indent + 6,
2532 // FIXME: if indent_style != Visual, then the budgets below might
2533 // be out by a char or two.
2535 let budget = context.config.max_width() - offset.width();
2536 let span_start = where_clause.predicates[0].span().lo();
2537 // If we don't have the start of the next span, then use the end of the
2538 // predicates, but that means we miss comments.
2539 let len = where_clause.predicates.len();
2540 let end_of_preds = where_clause.predicates[len - 1].span().hi();
2541 let span_end = span_end.unwrap_or(end_of_preds);
2542 let items = itemize_list(
2543 context.snippet_provider,
2544 where_clause.predicates.iter(),
2547 |pred| pred.span().lo(),
2548 |pred| pred.span().hi(),
2549 |pred| pred.rewrite(context, Shape::legacy(budget, offset)),
2554 let item_vec = items.collect::<Vec<_>>();
2555 // FIXME: we don't need to collect here
2556 let tactic = definitive_tactic(&item_vec, ListTactic::Vertical, Separator::Comma, budget);
2558 let mut comma_tactic = context.config.trailing_comma();
2559 // Kind of a hack because we don't usually have trailing commas in where clauses.
2560 if comma_tactic == SeparatorTactic::Vertical || where_clause_option.suppress_comma {
2561 comma_tactic = SeparatorTactic::Never;
2564 let fmt = ListFormatting {
2567 trailing_separator: comma_tactic,
2568 separator_place: SeparatorPlace::Back,
2569 shape: Shape::legacy(budget, offset),
2570 ends_with_newline: tactic.ends_with_newline(context.config.indent_style()),
2571 preserve_newline: true,
2572 config: context.config,
2574 let preds_str = write_list(&item_vec, &fmt)?;
2576 let end_length = if terminator == "{" {
2577 // If the brace is on the next line we don't need to count it otherwise it needs two
2580 BraceStyle::AlwaysNextLine | BraceStyle::SameLineWhere => 0,
2581 BraceStyle::PreferSameLine => 2,
2583 } else if terminator == "=" {
2588 if density == Density::Tall || preds_str.contains('\n')
2589 || shape.indent.width() + " where ".len() + preds_str.len() + end_length > shape.width
2593 (shape.indent + extra_indent).to_string(context.config),
2597 Some(format!(" where {}", preds_str))
2601 fn missing_span_before_after_where(
2602 before_item_span_end: BytePos,
2603 where_clause: &ast::WhereClause,
2605 let missing_span_before = mk_sp(before_item_span_end, where_clause.span.lo());
2607 let pos_after_where = where_clause.span.lo() + BytePos(5);
2608 let missing_span_after = mk_sp(pos_after_where, where_clause.predicates[0].span().lo());
2609 (missing_span_before, missing_span_after)
2612 fn rewrite_comments_before_after_where(
2613 context: &RewriteContext,
2614 span_before_where: Span,
2615 span_after_where: Span,
2617 ) -> Option<(String, String)> {
2618 let before_comment = rewrite_missing_comment(span_before_where, shape, context)?;
2619 let after_comment = rewrite_missing_comment(
2621 shape.block_indent(context.config.tab_spaces()),
2624 Some((before_comment, after_comment))
2627 fn format_header(item_name: &str, ident: ast::Ident, vis: &ast::Visibility) -> String {
2628 format!("{}{}{}", format_visibility(vis), item_name, ident)
2631 #[derive(PartialEq, Eq, Clone, Copy)]
2639 context: &RewriteContext,
2640 generics: &ast::Generics,
2641 brace_style: BraceStyle,
2642 brace_pos: BracePos,
2646 ) -> Option<String> {
2647 let shape = Shape::legacy(context.budget(used_width + offset.width()), offset);
2648 let mut result = rewrite_generics(context, "", generics, shape, span)?;
2650 let same_line_brace = if !generics.where_clause.predicates.is_empty() || result.contains('\n') {
2651 let budget = context.budget(last_line_used_width(&result, offset.width()));
2652 let mut option = WhereClauseOption::snuggled(&result);
2653 if brace_pos == BracePos::None {
2654 option.suppress_comma = true;
2656 // If the generics are not parameterized then generics.span.hi() == 0,
2657 // so we use span.lo(), which is the position after `struct Foo`.
2658 let span_end_before_where = if generics.is_parameterized() {
2663 let where_clause_str = rewrite_where_clause(
2665 &generics.where_clause,
2667 Shape::legacy(budget, offset.block_only()),
2671 span_end_before_where,
2675 result.push_str(&where_clause_str);
2676 brace_pos == BracePos::ForceSameLine || brace_style == BraceStyle::PreferSameLine
2677 || (generics.where_clause.predicates.is_empty()
2678 && trimmed_last_line_width(&result) == 1)
2680 brace_pos == BracePos::ForceSameLine || trimmed_last_line_width(&result) == 1
2681 || brace_style != BraceStyle::AlwaysNextLine
2683 if brace_pos == BracePos::None {
2684 return Some(result);
2686 let total_used_width = last_line_used_width(&result, used_width);
2687 let remaining_budget = context.budget(total_used_width);
2688 // If the same line brace if forced, it indicates that we are rewriting an item with empty body,
2689 // and hence we take the closer into account as well for one line budget.
2690 // We assume that the closer has the same length as the opener.
2691 let overhead = if brace_pos == BracePos::ForceSameLine {
2698 let forbid_same_line_brace = overhead > remaining_budget;
2699 if !forbid_same_line_brace && same_line_brace {
2703 result.push_str(&offset.block_only().to_string(context.config));
2710 impl Rewrite for ast::ForeignItem {
2711 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
2712 let attrs_str = self.attrs.rewrite(context, shape)?;
2713 // Drop semicolon or it will be interpreted as comment.
2714 // FIXME: this may be a faulty span from libsyntax.
2715 let span = mk_sp(self.span.lo(), self.span.hi() - BytePos(1));
2717 let item_str = match self.node {
2718 ast::ForeignItemKind::Fn(ref fn_decl, ref generics) => {
2723 &FnSig::new(fn_decl, generics, self.vis.clone()),
2727 ).map(|(s, _)| format!("{};", s))
2729 ast::ForeignItemKind::Static(ref ty, is_mutable) => {
2730 // FIXME(#21): we're dropping potential comments in between the
2731 // function keywords here.
2732 let vis = format_visibility(&self.vis);
2733 let mut_str = if is_mutable { "mut " } else { "" };
2734 let prefix = format!("{}static {}{}:", vis, mut_str, self.ident);
2736 rewrite_assign_rhs(context, prefix, &**ty, shape.sub_width(1)?).map(|s| s + ";")
2738 ast::ForeignItemKind::Ty => {
2739 let vis = format_visibility(&self.vis);
2740 Some(format!("{}type {};", vis, self.ident))
2742 ast::ForeignItemKind::Macro(ref mac) => {
2743 rewrite_macro(mac, None, context, shape, MacroPosition::Item)
2747 let missing_span = if self.attrs.is_empty() {
2748 mk_sp(self.span.lo(), self.span.lo())
2750 mk_sp(self.attrs[self.attrs.len() - 1].span.hi(), self.span.lo())
2752 combine_strs_with_missing_comments(
2763 impl Rewrite for ast::GenericParam {
2764 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
2766 ast::GenericParam::Lifetime(ref lifetime_def) => lifetime_def.rewrite(context, shape),
2767 ast::GenericParam::Type(ref ty) => ty.rewrite(context, shape),
2772 /// Rewrite an inline mod.
2773 pub fn rewrite_mod(item: &ast::Item) -> String {
2774 let mut result = String::with_capacity(32);
2775 result.push_str(&*format_visibility(&item.vis));
2776 result.push_str("mod ");
2777 result.push_str(&item.ident.to_string());
2782 /// Rewrite `extern crate foo;` WITHOUT attributes.
2783 pub fn rewrite_extern_crate(context: &RewriteContext, item: &ast::Item) -> Option<String> {
2784 assert!(is_extern_crate(item));
2785 let new_str = context.snippet(item.span);
2786 Some(if contains_comment(new_str) {
2789 let no_whitespace = &new_str.split_whitespace().collect::<Vec<&str>>().join(" ");
2790 String::from(&*Regex::new(r"\s;").unwrap().replace(no_whitespace, ";"))
2794 /// Returns true for `mod foo;`, false for `mod foo { .. }`.
2795 pub fn is_mod_decl(item: &ast::Item) -> bool {
2797 ast::ItemKind::Mod(ref m) => m.inner.hi() != item.span.hi(),
2802 pub fn is_use_item(item: &ast::Item) -> bool {
2804 ast::ItemKind::Use(_) => true,
2809 pub fn is_extern_crate(item: &ast::Item) -> bool {
2811 ast::ItemKind::ExternCrate(..) => true,