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};
24 use comment::{combine_strs_with_missing_comments, contains_comment, recover_comment_removed,
25 recover_missing_comment_in_span, rewrite_missing_comment, FindUncommented};
26 use config::{BraceStyle, Config, Density, IndentStyle};
27 use expr::{format_expr, is_empty_block, is_simple_block_stmt, rewrite_assign_rhs,
28 rewrite_assign_rhs_with, ExprType, RhsTactics};
29 use lists::{definitive_tactic, itemize_list, write_list, ListFormatting, ListItem, Separator};
30 use macros::{rewrite_macro, MacroPosition};
32 use rewrite::{Rewrite, RewriteContext};
33 use shape::{Indent, Shape};
35 use types::TraitTyParamBounds;
36 use utils::{colon_spaces, contains_skip, first_line_width, format_abi, format_auto,
37 format_constness, format_defaultness, format_mutability, format_unsafety,
38 format_visibility, is_attributes_extendable, last_line_contains_single_line_comment,
39 last_line_used_width, last_line_width, mk_sp, semicolon_for_expr, starts_with_newline,
40 stmt_expr, trimmed_last_line_width};
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 self.block_indent = self.block_indent.block_indent(self.config);
462 let variant_list = self.format_variant_list(enum_def, body_start, span.hi() - BytePos(1));
464 Some(ref body_str) => self.push_str(body_str),
465 None => self.format_missing_no_indent(span.hi() - BytePos(1)),
467 self.block_indent = self.block_indent.block_unindent(self.config);
469 if variant_list.is_some() || contains_comment(&enum_snippet[brace_pos..]) {
470 let indent_str = self.block_indent.to_string(self.config);
471 self.push_str(&indent_str);
474 self.last_pos = span.hi();
477 // Format the body of an enum definition
478 fn format_variant_list(
480 enum_def: &ast::EnumDef,
483 ) -> Option<String> {
484 if enum_def.variants.is_empty() {
487 let mut result = String::with_capacity(1024);
488 let indentation = self.block_indent.to_string_with_newline(self.config);
489 result.push_str(&indentation);
491 let itemize_list_with = |one_line_width: usize| {
493 self.snippet_provider,
494 enum_def.variants.iter(),
498 if !f.node.attrs.is_empty() {
499 f.node.attrs[0].span.lo()
505 |f| self.format_variant(f, one_line_width),
511 let mut items: Vec<_> =
512 itemize_list_with(self.config.width_heuristics().struct_variant_width);
513 // If one of the variants use multiple lines, use multi-lined formatting for all variants.
514 let has_multiline_variant = items.iter().any(|item| item.inner_as_ref().contains('\n'));
515 let has_single_line_variant = items.iter().any(|item| !item.inner_as_ref().contains('\n'));
516 if has_multiline_variant && has_single_line_variant {
517 items = itemize_list_with(0);
520 let shape = self.shape().sub_width(2)?;
521 let fmt = ListFormatting {
522 tactic: DefinitiveListTactic::Vertical,
524 trailing_separator: self.config.trailing_comma(),
525 separator_place: SeparatorPlace::Back,
527 ends_with_newline: true,
528 preserve_newline: true,
532 let list = write_list(&items, &fmt)?;
533 result.push_str(&list);
538 // Variant of an enum.
539 fn format_variant(&self, field: &ast::Variant, one_line_width: usize) -> Option<String> {
540 if contains_skip(&field.node.attrs) {
541 let lo = field.node.attrs[0].span.lo();
542 let span = mk_sp(lo, field.span.hi());
543 return Some(self.snippet(span).to_owned());
546 let context = self.get_context();
548 let shape = self.shape().sub_width(1)?;
549 let attrs_str = field.node.attrs.rewrite(&context, shape)?;
554 .map_or(field.span.lo(), |attr| attr.span.hi());
555 let span = mk_sp(lo, field.span.lo());
557 let variant_body = match field.node.data {
558 ast::VariantData::Tuple(..) | ast::VariantData::Struct(..) => format_struct(
560 &StructParts::from_variant(field),
562 Some(one_line_width),
564 ast::VariantData::Unit(..) => {
565 if let Some(ref expr) = field.node.disr_expr {
566 let lhs = format!("{} =", field.node.ident.name);
567 rewrite_assign_rhs(&context, lhs, &**expr, shape)?
569 field.node.ident.name.to_string()
574 combine_strs_with_missing_comments(&context, &attrs_str, &variant_body, span, shape, false)
579 context: &RewriteContext,
582 where_span_end: Option<BytePos>,
583 ) -> Option<String> {
584 if let ast::ItemKind::Impl(_, _, _, ref generics, _, ref self_ty, ref items) = item.node {
585 let mut result = String::with_capacity(128);
586 let ref_and_type = format_impl_ref_and_type(context, item, offset)?;
587 let sep = offset.to_string_with_newline(context.config);
588 result.push_str(&ref_and_type);
590 let where_budget = if result.contains('\n') {
591 context.config.max_width()
593 context.budget(last_line_width(&result))
595 let option = WhereClauseOption::snuggled(&ref_and_type);
596 let where_clause_str = rewrite_where_clause(
598 &generics.where_clause,
599 context.config.brace_style(),
600 Shape::legacy(where_budget, offset.block_only()),
609 // If there is no where clause, we may have missing comments between the trait name and
610 // the opening brace.
611 if generics.where_clause.predicates.is_empty() {
612 if let Some(hi) = where_span_end {
613 match recover_missing_comment_in_span(
614 mk_sp(self_ty.span.hi(), hi),
615 Shape::indented(offset, context.config),
617 last_line_width(&result),
619 Some(ref missing_comment) if !missing_comment.is_empty() => {
620 result.push_str(missing_comment);
627 if is_impl_single_line(context, items, &result, &where_clause_str, item)? {
628 result.push_str(&where_clause_str);
629 if where_clause_str.contains('\n') || last_line_contains_single_line_comment(&result) {
630 result.push_str(&format!("{}{{{}}}", &sep, &sep));
632 result.push_str(" {}");
637 if !where_clause_str.is_empty() && !where_clause_str.contains('\n') {
638 let width = offset.block_indent + context.config.tab_spaces() - 1;
639 let where_indent = Indent::new(0, width);
640 result.push_str(&where_indent.to_string_with_newline(context.config));
642 result.push_str(&where_clause_str);
644 let need_newline = last_line_contains_single_line_comment(&result) || result.contains('\n');
645 match context.config.brace_style() {
646 _ if need_newline => result.push_str(&sep),
647 BraceStyle::AlwaysNextLine => result.push_str(&sep),
648 BraceStyle::PreferSameLine => result.push(' '),
649 BraceStyle::SameLineWhere => {
650 if !where_clause_str.is_empty() {
651 result.push_str(&sep);
660 let snippet = context.snippet(item.span);
661 let open_pos = snippet.find_uncommented("{")? + 1;
663 if !items.is_empty() || contains_comment(&snippet[open_pos..]) {
664 let mut visitor = FmtVisitor::from_context(context);
665 let item_indent = offset.block_only().block_indent(context.config);
666 visitor.block_indent = item_indent;
667 visitor.last_pos = item.span.lo() + BytePos(open_pos as u32);
669 visitor.visit_attrs(&item.attrs, ast::AttrStyle::Inner);
670 if context.config.reorder_impl_items() {
671 // Create visitor for each items, then reorder them.
672 let mut buffer = vec![];
674 visitor.visit_impl_item(item);
675 buffer.push((visitor.buffer.clone(), item.clone()));
676 visitor.buffer.clear();
678 // type -> const -> macro -> method
679 use ast::ImplItemKind::*;
680 fn need_empty_line(a: &ast::ImplItemKind, b: &ast::ImplItemKind) -> bool {
682 (Type(..), Type(..)) | (Const(..), Const(..)) => false,
687 buffer.sort_by(|(_, a), (_, b)| match (&a.node, &b.node) {
688 (Type(..), _) => Ordering::Less,
689 (_, Type(..)) => Ordering::Greater,
690 (Const(..), _) => Ordering::Less,
691 (_, Const(..)) => Ordering::Greater,
692 (Macro(..), _) => Ordering::Less,
693 (_, Macro(..)) => Ordering::Greater,
696 let mut prev_kind = None;
697 for (buf, item) in buffer {
698 // Make sure that there are at least a single empty line between
699 // different impl items.
702 .map_or(false, |prev_kind| need_empty_line(prev_kind, &item.node))
704 visitor.push_str("\n");
706 visitor.push_str(&item_indent.to_string_with_newline(context.config));
707 visitor.push_str(buf.trim());
708 prev_kind = Some(item.node.clone());
712 visitor.visit_impl_item(item);
716 visitor.format_missing(item.span.hi() - BytePos(1));
718 let inner_indent_str = visitor.block_indent.to_string_with_newline(context.config);
719 let outer_indent_str = offset.block_only().to_string_with_newline(context.config);
721 result.push_str(&inner_indent_str);
722 result.push_str(visitor.buffer.to_string().trim());
723 result.push_str(&outer_indent_str);
726 if result.ends_with('{') {
727 result.push_str(&sep);
737 fn is_impl_single_line(
738 context: &RewriteContext,
739 items: &[ast::ImplItem],
741 where_clause_str: &str,
744 let snippet = context.snippet(item.span);
745 let open_pos = snippet.find_uncommented("{")? + 1;
748 context.config.empty_item_single_line() && items.is_empty() && !result.contains('\n')
749 && result.len() + where_clause_str.len() <= context.config.max_width()
750 && !contains_comment(&snippet[open_pos..]),
754 fn format_impl_ref_and_type(
755 context: &RewriteContext,
758 ) -> Option<String> {
759 if let ast::ItemKind::Impl(
769 let mut result = String::with_capacity(128);
771 result.push_str(&format_visibility(&item.vis));
772 result.push_str(format_defaultness(defaultness));
773 result.push_str(format_unsafety(unsafety));
775 let lo = context.snippet_provider.span_after(item.span, "impl");
776 let hi = match *trait_ref {
777 Some(ref tr) => tr.path.span.lo(),
778 None => self_ty.span.lo(),
780 let shape = generics_shape_from_config(
782 Shape::indented(offset + last_line_width(&result), context.config),
785 let generics_str = rewrite_generics(context, "impl", generics, shape, mk_sp(lo, hi))?;
786 result.push_str(&generics_str);
788 let polarity_str = if polarity == ast::ImplPolarity::Negative {
794 if let Some(ref trait_ref) = *trait_ref {
795 let result_len = last_line_width(&result);
796 result.push_str(&rewrite_trait_ref(
805 // Try to put the self type in a single line.
807 let trait_ref_overhead = if trait_ref.is_some() { 4 } else { 0 };
808 let curly_brace_overhead = if generics.where_clause.predicates.is_empty() {
809 // If there is no where clause adapt budget for type formatting to take space and curly
810 // brace into account.
811 match context.config.brace_style() {
812 BraceStyle::AlwaysNextLine => 0,
818 let used_space = last_line_width(&result) + trait_ref_overhead + curly_brace_overhead;
819 // 1 = space before the type.
820 let budget = context.budget(used_space + 1);
821 if let Some(self_ty_str) = self_ty.rewrite(context, Shape::legacy(budget, offset)) {
822 if !self_ty_str.contains('\n') {
823 if trait_ref.is_some() {
824 result.push_str(" for ");
828 result.push_str(&self_ty_str);
833 // Couldn't fit the self type on a single line, put it on a new line.
835 // Add indentation of one additional tab.
836 let new_line_offset = offset.block_indent(context.config);
837 result.push_str(&new_line_offset.to_string(context.config));
838 if trait_ref.is_some() {
839 result.push_str("for ");
841 let budget = context.budget(last_line_width(&result));
842 let type_offset = match context.config.indent_style() {
843 IndentStyle::Visual => new_line_offset + trait_ref_overhead,
844 IndentStyle::Block => new_line_offset,
846 result.push_str(&*self_ty.rewrite(context, Shape::legacy(budget, type_offset))?);
853 fn rewrite_trait_ref(
854 context: &RewriteContext,
855 trait_ref: &ast::TraitRef,
859 ) -> Option<String> {
860 // 1 = space between generics and trait_ref
861 let used_space = 1 + polarity_str.len() + result_len;
862 let shape = Shape::indented(offset + used_space, context.config);
863 if let Some(trait_ref_str) = trait_ref.rewrite(context, shape) {
864 if !trait_ref_str.contains('\n') {
865 return Some(format!(" {}{}", polarity_str, &trait_ref_str));
868 // We could not make enough space for trait_ref, so put it on new line.
869 let offset = offset.block_indent(context.config);
870 let shape = Shape::indented(offset, context.config);
871 let trait_ref_str = trait_ref.rewrite(context, shape)?;
874 &offset.to_string_with_newline(context.config),
880 pub struct StructParts<'a> {
883 vis: &'a ast::Visibility,
884 def: &'a ast::VariantData,
885 generics: Option<&'a ast::Generics>,
889 impl<'a> StructParts<'a> {
890 fn format_header(&self) -> String {
891 format_header(self.prefix, self.ident, self.vis)
894 fn from_variant(variant: &'a ast::Variant) -> Self {
897 ident: variant.node.ident,
898 vis: &DEFAULT_VISIBILITY,
899 def: &variant.node.data,
905 pub fn from_item(item: &'a ast::Item) -> Self {
906 let (prefix, def, generics) = match item.node {
907 ast::ItemKind::Struct(ref def, ref generics) => ("struct ", def, generics),
908 ast::ItemKind::Union(ref def, ref generics) => ("union ", def, generics),
916 generics: Some(generics),
923 context: &RewriteContext,
924 struct_parts: &StructParts,
926 one_line_width: Option<usize>,
927 ) -> Option<String> {
928 match *struct_parts.def {
929 ast::VariantData::Unit(..) => format_unit_struct(context, struct_parts, offset),
930 ast::VariantData::Tuple(ref fields, _) => {
931 format_tuple_struct(context, struct_parts, fields, offset)
933 ast::VariantData::Struct(ref fields, _) => {
934 format_struct_struct(context, struct_parts, fields, offset, one_line_width)
939 pub fn format_trait(context: &RewriteContext, item: &ast::Item, offset: Indent) -> Option<String> {
940 if let ast::ItemKind::Trait(
944 ref type_param_bounds,
948 let mut result = String::with_capacity(128);
949 let header = format!(
951 format_auto(is_auto),
952 format_visibility(&item.vis),
953 format_unsafety(unsafety),
955 result.push_str(&header);
957 let body_lo = context.snippet_provider.span_after(item.span, "{");
959 let shape = Shape::indented(offset, context.config).offset_left(result.len())?;
960 let generics_str = rewrite_generics(
962 &item.ident.to_string(),
965 mk_sp(item.span.lo(), body_lo),
967 result.push_str(&generics_str);
969 // FIXME(#2055): rustfmt fails to format when there are comments between trait bounds.
970 if !type_param_bounds.is_empty() {
971 let ident_hi = context
973 .span_after(item.span, &format!("{}", item.ident));
974 let bound_hi = type_param_bounds.last().unwrap().span().hi();
975 let snippet = context.snippet(mk_sp(ident_hi, bound_hi));
976 if contains_comment(snippet) {
980 if !type_param_bounds.is_empty() {
981 result = rewrite_assign_rhs_with(
984 &TraitTyParamBounds::new(type_param_bounds),
986 RhsTactics::ForceNextLine,
990 // Rewrite where clause.
991 if !generics.where_clause.predicates.is_empty() {
992 let where_density = if context.config.indent_style() == IndentStyle::Block {
998 let where_budget = context.budget(last_line_width(&result));
999 let pos_before_where = if type_param_bounds.is_empty() {
1000 generics.where_clause.span.lo()
1002 type_param_bounds[type_param_bounds.len() - 1].span().hi()
1004 let option = WhereClauseOption::snuggled(&generics_str);
1005 let where_clause_str = rewrite_where_clause(
1007 &generics.where_clause,
1008 context.config.brace_style(),
1009 Shape::legacy(where_budget, offset.block_only()),
1017 // If the where clause cannot fit on the same line,
1018 // put the where clause on a new line
1019 if !where_clause_str.contains('\n')
1020 && last_line_width(&result) + where_clause_str.len() + offset.width()
1021 > context.config.comment_width()
1023 let width = offset.block_indent + context.config.tab_spaces() - 1;
1024 let where_indent = Indent::new(0, width);
1025 result.push_str(&where_indent.to_string_with_newline(context.config));
1027 result.push_str(&where_clause_str);
1029 let item_snippet = context.snippet(item.span);
1030 if let Some(lo) = item_snippet.find('/') {
1032 let comment_hi = body_lo - BytePos(1);
1033 let comment_lo = item.span.lo() + BytePos(lo as u32);
1034 if comment_lo < comment_hi {
1035 match recover_missing_comment_in_span(
1036 mk_sp(comment_lo, comment_hi),
1037 Shape::indented(offset, context.config),
1039 last_line_width(&result),
1041 Some(ref missing_comment) if !missing_comment.is_empty() => {
1042 result.push_str(missing_comment);
1050 match context.config.brace_style() {
1051 _ if last_line_contains_single_line_comment(&result)
1052 || last_line_width(&result) + 2 > context.budget(offset.width()) =>
1054 result.push_str(&offset.to_string_with_newline(context.config));
1056 BraceStyle::AlwaysNextLine => {
1057 result.push_str(&offset.to_string_with_newline(context.config));
1059 BraceStyle::PreferSameLine => result.push(' '),
1060 BraceStyle::SameLineWhere => {
1061 if result.contains('\n')
1062 || (!generics.where_clause.predicates.is_empty() && !trait_items.is_empty())
1064 result.push_str(&offset.to_string_with_newline(context.config));
1072 let snippet = context.snippet(item.span);
1073 let open_pos = snippet.find_uncommented("{")? + 1;
1075 if !trait_items.is_empty() || contains_comment(&snippet[open_pos..]) {
1076 let mut visitor = FmtVisitor::from_context(context);
1077 visitor.block_indent = offset.block_only().block_indent(context.config);
1078 visitor.last_pos = item.span.lo() + BytePos(open_pos as u32);
1080 for item in trait_items {
1081 visitor.visit_trait_item(item);
1084 visitor.format_missing(item.span.hi() - BytePos(1));
1086 let inner_indent_str = visitor.block_indent.to_string_with_newline(context.config);
1087 let outer_indent_str = offset.block_only().to_string_with_newline(context.config);
1089 result.push_str(&inner_indent_str);
1090 result.push_str(visitor.buffer.to_string().trim());
1091 result.push_str(&outer_indent_str);
1092 } else if result.contains('\n') {
1103 pub fn format_trait_alias(
1104 context: &RewriteContext,
1106 generics: &ast::Generics,
1107 ty_param_bounds: &ast::TyParamBounds,
1109 ) -> Option<String> {
1110 let alias = ident.name.as_str();
1111 // 6 = "trait ", 2 = " ="
1112 let g_shape = shape.offset_left(6)?.sub_width(2)?;
1113 let generics_str = rewrite_generics(context, &alias, generics, g_shape, generics.span)?;
1114 let lhs = format!("trait {} =", generics_str);
1116 rewrite_assign_rhs(context, lhs, ty_param_bounds, shape.sub_width(1)?).map(|s| s + ";")
1119 fn format_unit_struct(context: &RewriteContext, p: &StructParts, offset: Indent) -> Option<String> {
1120 let header_str = format_header(p.prefix, p.ident, p.vis);
1121 let generics_str = if let Some(generics) = p.generics {
1122 let hi = if generics.where_clause.predicates.is_empty() {
1125 generics.where_clause.span.hi()
1130 context.config.brace_style(),
1133 mk_sp(generics.span.lo(), hi),
1134 last_line_width(&header_str),
1139 Some(format!("{}{};", header_str, generics_str))
1142 pub fn format_struct_struct(
1143 context: &RewriteContext,
1144 struct_parts: &StructParts,
1145 fields: &[ast::StructField],
1147 one_line_width: Option<usize>,
1148 ) -> Option<String> {
1149 let mut result = String::with_capacity(1024);
1150 let span = struct_parts.span;
1152 let header_str = struct_parts.format_header();
1153 result.push_str(&header_str);
1155 let header_hi = span.lo() + BytePos(header_str.len() as u32);
1156 let body_lo = context.snippet_provider.span_after(span, "{");
1158 let generics_str = match struct_parts.generics {
1159 Some(g) => format_generics(
1162 context.config.brace_style(),
1163 if fields.is_empty() {
1164 BracePos::ForceSameLine
1169 mk_sp(header_hi, body_lo),
1170 last_line_width(&result),
1173 // 3 = ` {}`, 2 = ` {`.
1174 let overhead = if fields.is_empty() { 3 } else { 2 };
1175 if (context.config.brace_style() == BraceStyle::AlwaysNextLine && !fields.is_empty())
1176 || context.config.max_width() < overhead + result.len()
1178 format!("\n{}{{", offset.block_only().to_string(context.config))
1185 let overhead = if fields.is_empty() { 1 } else { 0 };
1186 let total_width = result.len() + generics_str.len() + overhead;
1187 if !generics_str.is_empty() && !generics_str.contains('\n')
1188 && total_width > context.config.max_width()
1191 result.push_str(&offset.to_string(context.config));
1192 result.push_str(generics_str.trim_left());
1194 result.push_str(&generics_str);
1197 if fields.is_empty() {
1198 let snippet = context.snippet(mk_sp(body_lo, span.hi() - BytePos(1)));
1199 if snippet.trim().is_empty() {
1201 } else if snippet.trim_right_matches(&[' ', '\t'][..]).ends_with('\n') {
1203 result.push_str(snippet.trim_right());
1205 result.push_str(&offset.to_string(context.config));
1207 result.push_str(snippet);
1210 return Some(result);
1214 let one_line_budget = context.budget(result.len() + 3 + offset.width());
1215 let one_line_budget =
1216 one_line_width.map_or(0, |one_line_width| min(one_line_width, one_line_budget));
1218 let items_str = rewrite_with_alignment(
1221 Shape::indented(offset, context.config).sub_width(1)?,
1222 mk_sp(body_lo, span.hi()),
1226 if !items_str.contains('\n') && !result.contains('\n') && items_str.len() <= one_line_budget
1227 && !last_line_contains_single_line_comment(&items_str)
1229 Some(format!("{} {} }}", result, items_str))
1235 .block_indent(context.config)
1236 .to_string(context.config),
1238 offset.to_string(context.config)
1243 fn get_bytepos_after_visibility(vis: &ast::Visibility, default_span: Span) -> BytePos {
1245 ast::VisibilityKind::Crate(..) | ast::VisibilityKind::Restricted { .. } => vis.span.hi(),
1246 _ => default_span.lo(),
1250 fn format_tuple_struct(
1251 context: &RewriteContext,
1252 struct_parts: &StructParts,
1253 fields: &[ast::StructField],
1255 ) -> Option<String> {
1256 let mut result = String::with_capacity(1024);
1257 let span = struct_parts.span;
1259 let header_str = struct_parts.format_header();
1260 result.push_str(&header_str);
1262 let body_lo = if fields.is_empty() {
1263 let lo = get_bytepos_after_visibility(struct_parts.vis, span);
1266 .span_after(mk_sp(lo, span.hi()), "(")
1270 let body_hi = if fields.is_empty() {
1273 .span_after(mk_sp(body_lo, span.hi()), ")")
1275 // This is a dirty hack to work around a missing `)` from the span of the last field.
1276 let last_arg_span = fields[fields.len() - 1].span;
1277 if context.snippet(last_arg_span).ends_with(')') {
1282 .span_after(mk_sp(last_arg_span.hi(), span.hi()), ")")
1286 let where_clause_str = match struct_parts.generics {
1288 let budget = context.budget(last_line_width(&header_str));
1289 let shape = Shape::legacy(budget, offset);
1290 let g_span = mk_sp(span.lo(), body_lo);
1291 let generics_str = rewrite_generics(context, "", generics, shape, g_span)?;
1292 result.push_str(&generics_str);
1294 let where_budget = context.budget(last_line_width(&result));
1295 let option = WhereClauseOption::new(true, false);
1296 rewrite_where_clause(
1298 &generics.where_clause,
1299 context.config.brace_style(),
1300 Shape::legacy(where_budget, offset.block_only()),
1301 Density::Compressed,
1309 None => "".to_owned(),
1312 if fields.is_empty() {
1314 let used_width = last_line_used_width(&result, offset.width()) + 3;
1315 if used_width > context.config.max_width() {
1317 result.push_str(&offset
1318 .block_indent(context.config)
1319 .to_string(context.config))
1322 let snippet = context.snippet(mk_sp(
1326 .span_before(mk_sp(body_lo, span.hi()), ")"),
1328 if snippet.is_empty() {
1330 } else if snippet.trim_right_matches(&[' ', '\t'][..]).ends_with('\n') {
1331 result.push_str(snippet.trim_right());
1333 result.push_str(&offset.to_string(context.config));
1335 result.push_str(snippet);
1339 let shape = Shape::indented(offset, context.config).sub_width(1)?;
1340 let fields = &fields.iter().collect::<Vec<_>>();
1341 result = overflow::rewrite_with_parens(
1347 context.config.width_heuristics().fn_call_width,
1352 if !where_clause_str.is_empty() && !where_clause_str.contains('\n')
1353 && (result.contains('\n')
1354 || offset.block_indent + result.len() + where_clause_str.len() + 1
1355 > context.config.max_width())
1357 // We need to put the where clause on a new line, but we didn't
1358 // know that earlier, so the where clause will not be indented properly.
1361 .push_str(&(offset.block_only() + (context.config.tab_spaces() - 1))
1362 .to_string(context.config));
1364 result.push_str(&where_clause_str);
1369 pub fn rewrite_type_alias(
1370 context: &RewriteContext,
1374 generics: &ast::Generics,
1375 vis: &ast::Visibility,
1377 ) -> Option<String> {
1378 let mut result = String::with_capacity(128);
1380 result.push_str(&format_visibility(vis));
1381 result.push_str("type ");
1384 let g_shape = Shape::indented(indent, context.config)
1385 .offset_left(result.len())?
1388 context.snippet_provider.span_after(span, "type"),
1391 let generics_str = rewrite_generics(context, &ident.to_string(), generics, g_shape, g_span)?;
1392 result.push_str(&generics_str);
1394 let where_budget = context.budget(last_line_width(&result));
1395 let option = WhereClauseOption::snuggled(&result);
1396 let where_clause_str = rewrite_where_clause(
1398 &generics.where_clause,
1399 context.config.brace_style(),
1400 Shape::legacy(where_budget, indent),
1408 result.push_str(&where_clause_str);
1409 if where_clause_str.is_empty() {
1410 result.push_str(" =");
1412 result.push_str(&format!(
1414 indent.to_string_with_newline(context.config)
1419 let ty_shape = Shape::indented(indent, context.config).sub_width(1)?;
1420 rewrite_assign_rhs(context, result, ty, ty_shape).map(|s| s + ";")
1423 fn type_annotation_spacing(config: &Config) -> (&str, &str) {
1425 if config.space_before_colon() { " " } else { "" },
1426 if config.space_after_colon() { " " } else { "" },
1430 pub fn rewrite_struct_field_prefix(
1431 context: &RewriteContext,
1432 field: &ast::StructField,
1433 ) -> Option<String> {
1434 let vis = format_visibility(&field.vis);
1435 let type_annotation_spacing = type_annotation_spacing(context.config);
1436 Some(match field.ident {
1437 Some(name) => format!("{}{}{}:", vis, name, type_annotation_spacing.0),
1438 None => format!("{}", vis),
1442 impl Rewrite for ast::StructField {
1443 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
1444 rewrite_struct_field(context, self, shape, 0)
1448 pub fn rewrite_struct_field(
1449 context: &RewriteContext,
1450 field: &ast::StructField,
1452 lhs_max_width: usize,
1453 ) -> Option<String> {
1454 if contains_skip(&field.attrs) {
1455 return Some(context.snippet(field.span()).to_owned());
1458 let type_annotation_spacing = type_annotation_spacing(context.config);
1459 let prefix = rewrite_struct_field_prefix(context, field)?;
1461 let attrs_str = field.attrs.rewrite(context, shape)?;
1462 let attrs_extendable = field.ident.is_none() && is_attributes_extendable(&attrs_str);
1463 let missing_span = if field.attrs.is_empty() {
1464 mk_sp(field.span.lo(), field.span.lo())
1466 mk_sp(field.attrs.last().unwrap().span.hi(), field.span.lo())
1468 let mut spacing = String::from(if field.ident.is_some() {
1469 type_annotation_spacing.1
1473 // Try to put everything on a single line.
1474 let attr_prefix = combine_strs_with_missing_comments(
1482 let overhead = last_line_width(&attr_prefix);
1483 let lhs_offset = lhs_max_width.checked_sub(overhead).unwrap_or(0);
1484 for _ in 0..lhs_offset {
1487 // In this extreme case we will be missing a space betweeen an attribute and a field.
1488 if prefix.is_empty() && !attrs_str.is_empty() && attrs_extendable && spacing.is_empty() {
1492 .offset_left(overhead + spacing.len())
1493 .and_then(|ty_shape| field.ty.rewrite(context, ty_shape));
1494 if let Some(ref ty) = orig_ty {
1495 if !ty.contains('\n') {
1496 return Some(attr_prefix + &spacing + ty);
1500 let is_prefix_empty = prefix.is_empty();
1501 // We must use multiline. We are going to put attributes and a field on different lines.
1502 let field_str = rewrite_assign_rhs(context, prefix, &*field.ty, shape)?;
1503 // Remove a leading white-space from `rewrite_assign_rhs()` when rewriting a tuple struct.
1504 let field_str = if is_prefix_empty {
1505 field_str.trim_left()
1509 combine_strs_with_missing_comments(context, &attrs_str, field_str, missing_span, shape, false)
1512 pub struct StaticParts<'a> {
1514 vis: &'a ast::Visibility,
1517 mutability: ast::Mutability,
1518 expr_opt: Option<&'a ptr::P<ast::Expr>>,
1519 defaultness: Option<ast::Defaultness>,
1523 impl<'a> StaticParts<'a> {
1524 pub fn from_item(item: &'a ast::Item) -> Self {
1525 let (prefix, ty, mutability, expr) = match item.node {
1526 ast::ItemKind::Static(ref ty, mutability, ref expr) => ("static", ty, mutability, expr),
1527 ast::ItemKind::Const(ref ty, ref expr) => {
1528 ("const", ty, ast::Mutability::Immutable, expr)
1530 _ => unreachable!(),
1538 expr_opt: Some(expr),
1544 pub fn from_trait_item(ti: &'a ast::TraitItem) -> Self {
1545 let (ty, expr_opt) = match ti.node {
1546 ast::TraitItemKind::Const(ref ty, ref expr_opt) => (ty, expr_opt),
1547 _ => unreachable!(),
1551 vis: &DEFAULT_VISIBILITY,
1554 mutability: ast::Mutability::Immutable,
1555 expr_opt: expr_opt.as_ref(),
1561 pub fn from_impl_item(ii: &'a ast::ImplItem) -> Self {
1562 let (ty, expr) = match ii.node {
1563 ast::ImplItemKind::Const(ref ty, ref expr) => (ty, expr),
1564 _ => unreachable!(),
1571 mutability: ast::Mutability::Immutable,
1572 expr_opt: Some(expr),
1573 defaultness: Some(ii.defaultness),
1580 context: &RewriteContext,
1581 static_parts: &StaticParts,
1583 ) -> Option<String> {
1584 let colon = colon_spaces(
1585 context.config.space_before_colon(),
1586 context.config.space_after_colon(),
1588 let mut prefix = format!(
1590 format_visibility(static_parts.vis),
1591 static_parts.defaultness.map_or("", format_defaultness),
1592 static_parts.prefix,
1593 format_mutability(static_parts.mutability),
1599 Shape::indented(offset.block_only(), context.config).offset_left(prefix.len() + 2)?;
1600 let ty_str = match static_parts.ty.rewrite(context, ty_shape) {
1601 Some(ty_str) => ty_str,
1603 if prefix.ends_with(' ') {
1606 let nested_indent = offset.block_indent(context.config);
1607 let nested_shape = Shape::indented(nested_indent, context.config);
1608 let ty_str = static_parts.ty.rewrite(context, nested_shape)?;
1611 nested_indent.to_string_with_newline(context.config),
1617 if let Some(expr) = static_parts.expr_opt {
1618 let lhs = format!("{}{} =", prefix, ty_str);
1620 let remaining_width = context.budget(offset.block_indent + 1);
1625 Shape::legacy(remaining_width, offset.block_only()),
1626 ).and_then(|res| recover_comment_removed(res, static_parts.span, context))
1627 .map(|s| if s.ends_with(';') { s } else { s + ";" })
1629 Some(format!("{}{};", prefix, ty_str))
1633 pub fn rewrite_associated_type(
1635 ty_opt: Option<&ptr::P<ast::Ty>>,
1636 ty_param_bounds_opt: Option<&ast::TyParamBounds>,
1637 context: &RewriteContext,
1639 ) -> Option<String> {
1640 let prefix = format!("type {}", ident);
1642 let type_bounds_str = if let Some(bounds) = ty_param_bounds_opt {
1643 if bounds.is_empty() {
1647 let shape = Shape::indented(indent, context.config).offset_left(prefix.len() + 2)?;
1648 bounds.rewrite(context, shape).map(|s| format!(": {}", s))?
1654 if let Some(ty) = ty_opt {
1656 let shape = Shape::indented(indent, context.config).sub_width(1)?;
1657 let lhs = format!("{}{} =", prefix, type_bounds_str);
1658 rewrite_assign_rhs(context, lhs, &**ty, shape).map(|s| s + ";")
1660 Some(format!("{}{};", prefix, type_bounds_str))
1664 pub fn rewrite_associated_impl_type(
1666 defaultness: ast::Defaultness,
1667 ty_opt: Option<&ptr::P<ast::Ty>>,
1668 ty_param_bounds_opt: Option<&ast::TyParamBounds>,
1669 context: &RewriteContext,
1671 ) -> Option<String> {
1672 let result = rewrite_associated_type(ident, ty_opt, ty_param_bounds_opt, context, indent)?;
1675 ast::Defaultness::Default => Some(format!("default {}", result)),
1680 impl Rewrite for ast::FunctionRetTy {
1681 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
1683 ast::FunctionRetTy::Default(_) => Some(String::new()),
1684 ast::FunctionRetTy::Ty(ref ty) => {
1685 let inner_width = shape.width.checked_sub(3)?;
1686 ty.rewrite(context, Shape::legacy(inner_width, shape.indent + 3))
1687 .map(|r| format!("-> {}", r))
1693 fn is_empty_infer(context: &RewriteContext, ty: &ast::Ty) -> bool {
1695 ast::TyKind::Infer => {
1696 let original = context.snippet(ty.span);
1703 impl Rewrite for ast::Arg {
1704 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
1705 if is_named_arg(self) {
1706 let mut result = self.pat
1707 .rewrite(context, Shape::legacy(shape.width, shape.indent))?;
1709 if !is_empty_infer(context, &*self.ty) {
1710 if context.config.space_before_colon() {
1711 result.push_str(" ");
1713 result.push_str(":");
1714 if context.config.space_after_colon() {
1715 result.push_str(" ");
1717 let overhead = last_line_width(&result);
1718 let max_width = shape.width.checked_sub(overhead)?;
1719 let ty_str = self.ty
1720 .rewrite(context, Shape::legacy(max_width, shape.indent))?;
1721 result.push_str(&ty_str);
1726 self.ty.rewrite(context, shape)
1731 fn rewrite_explicit_self(
1732 explicit_self: &ast::ExplicitSelf,
1734 context: &RewriteContext,
1735 ) -> Option<String> {
1736 match explicit_self.node {
1737 ast::SelfKind::Region(lt, m) => {
1738 let mut_str = format_mutability(m);
1741 let lifetime_str = l.rewrite(
1743 Shape::legacy(context.config.max_width(), Indent::empty()),
1745 Some(format!("&{} {}self", lifetime_str, mut_str))
1747 None => Some(format!("&{}self", mut_str)),
1750 ast::SelfKind::Explicit(ref ty, _) => {
1751 assert!(!args.is_empty(), "&[ast::Arg] shouldn't be empty.");
1753 let mutability = explicit_self_mutability(&args[0]);
1754 let type_str = ty.rewrite(
1756 Shape::legacy(context.config.max_width(), Indent::empty()),
1761 format_mutability(mutability),
1765 ast::SelfKind::Value(_) => {
1766 assert!(!args.is_empty(), "&[ast::Arg] shouldn't be empty.");
1768 let mutability = explicit_self_mutability(&args[0]);
1770 Some(format!("{}self", format_mutability(mutability)))
1775 // Hacky solution caused by absence of `Mutability` in `SelfValue` and
1776 // `SelfExplicit` variants of `ast::ExplicitSelf_`.
1777 fn explicit_self_mutability(arg: &ast::Arg) -> ast::Mutability {
1778 if let ast::PatKind::Ident(ast::BindingMode::ByValue(mutability), _, _) = arg.pat.node {
1785 pub fn span_lo_for_arg(arg: &ast::Arg) -> BytePos {
1786 if is_named_arg(arg) {
1793 pub fn span_hi_for_arg(context: &RewriteContext, arg: &ast::Arg) -> BytePos {
1795 ast::TyKind::Infer if context.snippet(arg.ty.span) == "_" => arg.ty.span.hi(),
1796 ast::TyKind::Infer if is_named_arg(arg) => arg.pat.span.hi(),
1797 _ => arg.ty.span.hi(),
1801 pub fn is_named_arg(arg: &ast::Arg) -> bool {
1802 if let ast::PatKind::Ident(_, ident, _) = arg.pat.node {
1803 ident != symbol::keywords::Invalid.ident()
1809 // Return type is (result, force_new_line_for_brace)
1811 context: &RewriteContext,
1816 newline_brace: bool,
1818 ) -> Option<(String, bool)> {
1819 let mut force_new_line_for_brace = false;
1821 let where_clause = &fn_sig.generics.where_clause;
1823 let mut result = String::with_capacity(1024);
1824 result.push_str(&fn_sig.to_str(context));
1827 result.push_str("fn ");
1830 let overhead = if has_body && !newline_brace {
1837 let used_width = last_line_used_width(&result, indent.width());
1838 let one_line_budget = context.budget(used_width + overhead);
1840 width: one_line_budget,
1844 let fd = fn_sig.decl;
1845 let g_span = mk_sp(span.lo(), fd.output.span().lo());
1847 rewrite_generics(context, &ident.to_string(), fn_sig.generics, shape, g_span)?;
1848 result.push_str(&generics_str);
1850 let snuggle_angle_bracket = generics_str
1853 .map_or(false, |l| l.trim_left().len() == 1);
1855 // Note that the width and indent don't really matter, we'll re-layout the
1856 // return type later anyway.
1857 let ret_str = fd.output
1858 .rewrite(context, Shape::indented(indent, context.config))?;
1860 let multi_line_ret_str = ret_str.contains('\n');
1861 let ret_str_len = if multi_line_ret_str { 0 } else { ret_str.len() };
1864 let (one_line_budget, multi_line_budget, mut arg_indent) = compute_budgets_for_args(
1875 "rewrite_fn_base: one_line_budget: {}, multi_line_budget: {}, arg_indent: {:?}",
1876 one_line_budget, multi_line_budget, arg_indent
1879 // Check if vertical layout was forced.
1880 if one_line_budget == 0 {
1881 if snuggle_angle_bracket {
1884 result.push_str("(");
1885 if context.config.indent_style() == IndentStyle::Visual {
1886 result.push_str(&arg_indent.to_string_with_newline(context.config));
1892 if context.config.spaces_within_parens_and_brackets() && !fd.inputs.is_empty()
1893 && result.ends_with('(')
1898 // Skip `pub(crate)`.
1899 let lo_after_visibility = get_bytepos_after_visibility(&fn_sig.visibility, span);
1900 // A conservative estimation, to goal is to be over all parens in generics
1901 let args_start = fn_sig
1906 .map_or(lo_after_visibility, |param| param.span().hi());
1907 let args_end = if fd.inputs.is_empty() {
1910 .span_after(mk_sp(args_start, span.hi()), ")")
1912 let last_span = mk_sp(fd.inputs[fd.inputs.len() - 1].span().hi(), span.hi());
1913 context.snippet_provider.span_after(last_span, ")")
1915 let args_span = mk_sp(
1918 .span_after(mk_sp(args_start, span.hi()), "("),
1921 let arg_str = rewrite_args(
1924 fd.get_self().as_ref(),
1931 generics_str.contains('\n'),
1934 let put_args_in_block = match context.config.indent_style() {
1935 IndentStyle::Block => arg_str.contains('\n') || arg_str.len() > one_line_budget,
1937 } && !fd.inputs.is_empty();
1939 let mut args_last_line_contains_comment = false;
1940 if put_args_in_block {
1941 arg_indent = indent.block_indent(context.config);
1942 result.push_str(&arg_indent.to_string_with_newline(context.config));
1943 result.push_str(&arg_str);
1944 result.push_str(&indent.to_string_with_newline(context.config));
1947 result.push_str(&arg_str);
1948 let used_width = last_line_used_width(&result, indent.width()) + first_line_width(&ret_str);
1949 // Put the closing brace on the next line if it overflows the max width.
1951 if fd.inputs.is_empty() && used_width + 1 > context.config.max_width() {
1954 if context.config.spaces_within_parens_and_brackets() && !fd.inputs.is_empty() {
1957 // If the last line of args contains comment, we cannot put the closing paren
1958 // on the same line.
1962 .map_or(false, |last_line| last_line.contains("//"))
1964 args_last_line_contains_comment = true;
1965 result.push_str(&arg_indent.to_string_with_newline(context.config));
1971 if let ast::FunctionRetTy::Ty(..) = fd.output {
1972 let ret_should_indent = match context.config.indent_style() {
1973 // If our args are block layout then we surely must have space.
1974 IndentStyle::Block if put_args_in_block || fd.inputs.is_empty() => false,
1975 _ if args_last_line_contains_comment => false,
1976 _ if result.contains('\n') || multi_line_ret_str => true,
1978 // If the return type would push over the max width, then put the return type on
1979 // a new line. With the +1 for the signature length an additional space between
1980 // the closing parenthesis of the argument and the arrow '->' is considered.
1981 let mut sig_length = result.len() + indent.width() + ret_str_len + 1;
1983 // If there is no where clause, take into account the space after the return type
1985 if where_clause.predicates.is_empty() {
1989 sig_length > context.config.max_width()
1992 let ret_indent = if ret_should_indent {
1993 let indent = if arg_str.is_empty() {
1994 // Aligning with non-existent args looks silly.
1995 force_new_line_for_brace = true;
1998 // FIXME: we might want to check that using the arg indent
1999 // doesn't blow our budget, and if it does, then fallback to
2000 // the where clause indent.
2004 result.push_str(&indent.to_string_with_newline(context.config));
2008 Indent::new(indent.block_indent, last_line_width(&result))
2011 if multi_line_ret_str || ret_should_indent {
2012 // Now that we know the proper indent and width, we need to
2013 // re-layout the return type.
2014 let ret_str = fd.output
2015 .rewrite(context, Shape::indented(ret_indent, context.config))?;
2016 result.push_str(&ret_str);
2018 result.push_str(&ret_str);
2021 // Comment between return type and the end of the decl.
2022 let snippet_lo = fd.output.span().hi();
2023 if where_clause.predicates.is_empty() {
2024 let snippet_hi = span.hi();
2025 let snippet = context.snippet(mk_sp(snippet_lo, snippet_hi));
2026 // Try to preserve the layout of the original snippet.
2027 let original_starts_with_newline = snippet
2029 .map_or(false, |i| starts_with_newline(&snippet[i..]));
2030 let original_ends_with_newline = snippet
2031 .rfind(|c| c != ' ')
2032 .map_or(false, |i| snippet[i..].ends_with('\n'));
2033 let snippet = snippet.trim();
2034 if !snippet.is_empty() {
2035 result.push(if original_starts_with_newline {
2040 result.push_str(snippet);
2041 if original_ends_with_newline {
2042 force_new_line_for_brace = true;
2048 let pos_before_where = match fd.output {
2049 ast::FunctionRetTy::Default(..) => args_span.hi(),
2050 ast::FunctionRetTy::Ty(ref ty) => ty.span.hi(),
2053 let is_args_multi_lined = arg_str.contains('\n');
2055 let option = WhereClauseOption::new(!has_body, put_args_in_block && ret_str.is_empty());
2056 let where_clause_str = rewrite_where_clause(
2059 context.config.brace_style(),
2060 Shape::indented(indent, context.config),
2066 is_args_multi_lined,
2068 // If there are neither where clause nor return type, we may be missing comments between
2070 if where_clause_str.is_empty() {
2071 if let ast::FunctionRetTy::Default(ret_span) = fd.output {
2072 match recover_missing_comment_in_span(
2073 mk_sp(args_span.hi(), ret_span.hi()),
2076 last_line_width(&result),
2078 Some(ref missing_comment) if !missing_comment.is_empty() => {
2079 result.push_str(missing_comment);
2080 force_new_line_for_brace = true;
2087 result.push_str(&where_clause_str);
2089 force_new_line_for_brace |= last_line_contains_single_line_comment(&result);
2090 force_new_line_for_brace |= is_args_multi_lined && context.config.where_single_line();
2091 Some((result, force_new_line_for_brace))
2094 #[derive(Copy, Clone)]
2095 struct WhereClauseOption {
2096 suppress_comma: bool, // Force no trailing comma
2097 snuggle: bool, // Do not insert newline before `where`
2098 compress_where: bool, // Try single line where clause instead of vertical layout
2101 impl WhereClauseOption {
2102 pub fn new(suppress_comma: bool, snuggle: bool) -> WhereClauseOption {
2106 compress_where: false,
2110 pub fn snuggled(current: &str) -> WhereClauseOption {
2112 suppress_comma: false,
2113 snuggle: trimmed_last_line_width(current) == 1,
2114 compress_where: false,
2120 context: &RewriteContext,
2122 explicit_self: Option<&ast::ExplicitSelf>,
2123 one_line_budget: usize,
2124 multi_line_budget: usize,
2129 generics_str_contains_newline: bool,
2130 ) -> Option<String> {
2131 let mut arg_item_strs = args.iter()
2132 .map(|arg| arg.rewrite(context, Shape::legacy(multi_line_budget, arg_indent)))
2133 .collect::<Option<Vec<_>>>()?;
2135 // Account for sugary self.
2136 // FIXME: the comment for the self argument is dropped. This is blocked
2137 // on rust issue #27522.
2138 let min_args = explicit_self
2139 .and_then(|explicit_self| rewrite_explicit_self(explicit_self, args, context))
2140 .map_or(1, |self_str| {
2141 arg_item_strs[0] = self_str;
2145 // Comments between args.
2146 let mut arg_items = Vec::new();
2148 arg_items.push(ListItem::from_str(""));
2151 // FIXME(#21): if there are no args, there might still be a comment, but
2152 // without spans for the comment or parens, there is no chance of
2153 // getting it right. You also don't get to put a comment on self, unless
2155 if args.len() >= min_args || variadic {
2156 let comment_span_start = if min_args == 2 {
2157 let second_arg_start = if arg_has_pattern(&args[1]) {
2158 args[1].pat.span.lo()
2160 args[1].ty.span.lo()
2162 let reduced_span = mk_sp(span.lo(), second_arg_start);
2164 context.snippet_provider.span_after_last(reduced_span, ",")
2169 enum ArgumentKind<'a> {
2170 Regular(&'a ast::Arg),
2174 let variadic_arg = if variadic {
2175 let variadic_span = mk_sp(args.last().unwrap().ty.span.hi(), span.hi());
2176 let variadic_start =
2177 context.snippet_provider.span_after(variadic_span, "...") - BytePos(3);
2178 Some(ArgumentKind::Variadic(variadic_start))
2183 let more_items = itemize_list(
2184 context.snippet_provider,
2185 args[min_args - 1..]
2187 .map(ArgumentKind::Regular)
2188 .chain(variadic_arg),
2192 ArgumentKind::Regular(arg) => span_lo_for_arg(arg),
2193 ArgumentKind::Variadic(start) => start,
2196 ArgumentKind::Regular(arg) => arg.ty.span.hi(),
2197 ArgumentKind::Variadic(start) => start + BytePos(3),
2200 ArgumentKind::Regular(..) => None,
2201 ArgumentKind::Variadic(..) => Some("...".to_owned()),
2208 arg_items.extend(more_items);
2211 let fits_in_one_line = !generics_str_contains_newline
2212 && (arg_items.is_empty()
2213 || arg_items.len() == 1 && arg_item_strs[0].len() <= one_line_budget);
2215 for (item, arg) in arg_items.iter_mut().zip(arg_item_strs) {
2216 item.item = Some(arg);
2219 let last_line_ends_with_comment = arg_items
2222 .and_then(|item| item.post_comment.as_ref())
2223 .map_or(false, |s| s.trim().starts_with("//"));
2225 let (indent, trailing_comma) = match context.config.indent_style() {
2226 IndentStyle::Block if fits_in_one_line => {
2227 (indent.block_indent(context.config), SeparatorTactic::Never)
2229 IndentStyle::Block => (
2230 indent.block_indent(context.config),
2231 context.config.trailing_comma(),
2233 IndentStyle::Visual if last_line_ends_with_comment => {
2234 (arg_indent, context.config.trailing_comma())
2236 IndentStyle::Visual => (arg_indent, SeparatorTactic::Never),
2239 let tactic = definitive_tactic(
2241 context.config.fn_args_density().to_list_tactic(),
2245 let budget = match tactic {
2246 DefinitiveListTactic::Horizontal => one_line_budget,
2247 _ => multi_line_budget,
2250 debug!("rewrite_args: budget: {}, tactic: {:?}", budget, tactic);
2252 let fmt = ListFormatting {
2255 trailing_separator: if variadic {
2256 SeparatorTactic::Never
2260 separator_place: SeparatorPlace::Back,
2261 shape: Shape::legacy(budget, indent),
2262 ends_with_newline: tactic.ends_with_newline(context.config.indent_style()),
2263 preserve_newline: true,
2264 config: context.config,
2267 write_list(&arg_items, &fmt)
2270 fn arg_has_pattern(arg: &ast::Arg) -> bool {
2271 if let ast::PatKind::Ident(_, ident, _) = arg.pat.node {
2272 ident != symbol::keywords::Invalid.ident()
2278 fn compute_budgets_for_args(
2279 context: &RewriteContext,
2283 newline_brace: bool,
2285 force_vertical_layout: bool,
2286 ) -> Option<((usize, usize, Indent))> {
2288 "compute_budgets_for_args {} {:?}, {}, {}",
2294 // Try keeping everything on the same line.
2295 if !result.contains('\n') && !force_vertical_layout {
2296 // 2 = `()`, 3 = `() `, space is before ret_string.
2297 let overhead = if ret_str_len == 0 { 2 } else { 3 };
2298 let mut used_space = indent.width() + result.len() + ret_str_len + overhead;
2308 let one_line_budget = context.budget(used_space);
2310 if one_line_budget > 0 {
2312 let (indent, multi_line_budget) = match context.config.indent_style() {
2313 IndentStyle::Block => {
2314 let indent = indent.block_indent(context.config);
2315 (indent, context.budget(indent.width() + 1))
2317 IndentStyle::Visual => {
2318 let indent = indent + result.len() + 1;
2319 let multi_line_overhead = indent.width() + if newline_brace { 2 } else { 4 };
2320 (indent, context.budget(multi_line_overhead))
2324 return Some((one_line_budget, multi_line_budget, indent));
2328 // Didn't work. we must force vertical layout and put args on a newline.
2329 let new_indent = indent.block_indent(context.config);
2330 let used_space = match context.config.indent_style() {
2332 IndentStyle::Block => new_indent.width() + 1,
2333 // Account for `)` and possibly ` {`.
2334 IndentStyle::Visual => new_indent.width() + if ret_str_len == 0 { 1 } else { 3 },
2336 Some((0, context.budget(used_space), new_indent))
2339 fn newline_for_brace(config: &Config, where_clause: &ast::WhereClause) -> bool {
2340 let predicate_count = where_clause.predicates.len();
2342 if config.where_single_line() && predicate_count == 1 {
2345 let brace_style = config.brace_style();
2347 brace_style == BraceStyle::AlwaysNextLine
2348 || (brace_style == BraceStyle::SameLineWhere && predicate_count > 0)
2351 fn rewrite_generics(
2352 context: &RewriteContext,
2354 generics: &ast::Generics,
2357 ) -> Option<String> {
2358 // FIXME: convert bounds to where clauses where they get too big or if
2359 // there is a where clause at all.
2361 if generics.params.is_empty() {
2362 return Some(ident.to_owned());
2365 let params = &generics.params.iter().map(|e| &*e).collect::<Vec<_>>();
2366 overflow::rewrite_with_angle_brackets(context, ident, params, shape, span)
2369 pub fn generics_shape_from_config(config: &Config, shape: Shape, offset: usize) -> Option<Shape> {
2370 match config.indent_style() {
2371 IndentStyle::Visual => shape.visual_indent(1 + offset).sub_width(offset + 2),
2372 IndentStyle::Block => {
2376 .block_indent(config.tab_spaces())
2377 .with_max_width(config)
2383 fn rewrite_where_clause_rfc_style(
2384 context: &RewriteContext,
2385 where_clause: &ast::WhereClause,
2388 span_end: Option<BytePos>,
2389 span_end_before_where: BytePos,
2390 where_clause_option: WhereClauseOption,
2391 is_args_multi_line: bool,
2392 ) -> Option<String> {
2393 let block_shape = shape.block().with_max_width(context.config);
2395 let (span_before, span_after) =
2396 missing_span_before_after_where(span_end_before_where, where_clause);
2397 let (comment_before, comment_after) =
2398 rewrite_comments_before_after_where(context, span_before, span_after, shape)?;
2400 let starting_newline = if where_clause_option.snuggle && comment_before.is_empty() {
2403 block_shape.indent.to_string_with_newline(context.config)
2406 let clause_shape = block_shape.block_left(context.config.tab_spaces())?;
2408 let clause_shape = clause_shape.sub_width(1)?;
2409 // each clause on one line, trailing comma (except if suppress_comma)
2410 let span_start = where_clause.predicates[0].span().lo();
2411 // If we don't have the start of the next span, then use the end of the
2412 // predicates, but that means we miss comments.
2413 let len = where_clause.predicates.len();
2414 let end_of_preds = where_clause.predicates[len - 1].span().hi();
2415 let span_end = span_end.unwrap_or(end_of_preds);
2416 let items = itemize_list(
2417 context.snippet_provider,
2418 where_clause.predicates.iter(),
2421 |pred| pred.span().lo(),
2422 |pred| pred.span().hi(),
2423 |pred| pred.rewrite(context, clause_shape),
2428 let where_single_line = context.config.where_single_line() && len == 1 && !is_args_multi_line;
2429 let comma_tactic = if where_clause_option.suppress_comma || where_single_line {
2430 SeparatorTactic::Never
2432 context.config.trailing_comma()
2435 // shape should be vertical only and only if we have `where_single_line` option enabled
2436 // and the number of items of the where clause is equal to 1
2437 let shape_tactic = if where_single_line {
2438 DefinitiveListTactic::Horizontal
2440 DefinitiveListTactic::Vertical
2443 let fmt = ListFormatting {
2444 tactic: shape_tactic,
2446 trailing_separator: comma_tactic,
2447 separator_place: SeparatorPlace::Back,
2448 shape: clause_shape,
2449 ends_with_newline: true,
2450 preserve_newline: true,
2451 config: context.config,
2453 let preds_str = write_list(&items.collect::<Vec<_>>(), &fmt)?;
2455 let comment_separator = |comment: &str, shape: Shape| {
2456 if comment.is_empty() {
2459 shape.indent.to_string_with_newline(context.config)
2462 let newline_before_where = comment_separator(&comment_before, shape);
2463 let newline_after_where = comment_separator(&comment_after, clause_shape);
2466 let clause_sep = if where_clause_option.compress_where && comment_before.is_empty()
2467 && comment_after.is_empty() && !preds_str.contains('\n')
2468 && 6 + preds_str.len() <= shape.width || where_single_line
2472 clause_shape.indent.to_string_with_newline(context.config)
2475 "{}{}{}where{}{}{}{}",
2478 newline_before_where,
2479 newline_after_where,
2486 fn rewrite_where_clause(
2487 context: &RewriteContext,
2488 where_clause: &ast::WhereClause,
2489 brace_style: BraceStyle,
2493 span_end: Option<BytePos>,
2494 span_end_before_where: BytePos,
2495 where_clause_option: WhereClauseOption,
2496 is_args_multi_line: bool,
2497 ) -> Option<String> {
2498 if where_clause.predicates.is_empty() {
2499 return Some(String::new());
2502 if context.config.indent_style() == IndentStyle::Block {
2503 return rewrite_where_clause_rfc_style(
2509 span_end_before_where,
2510 where_clause_option,
2515 let extra_indent = Indent::new(context.config.tab_spaces(), 0);
2517 let offset = match context.config.indent_style() {
2518 IndentStyle::Block => shape.indent + extra_indent.block_indent(context.config),
2519 // 6 = "where ".len()
2520 IndentStyle::Visual => shape.indent + extra_indent + 6,
2522 // FIXME: if indent_style != Visual, then the budgets below might
2523 // be out by a char or two.
2525 let budget = context.config.max_width() - offset.width();
2526 let span_start = where_clause.predicates[0].span().lo();
2527 // If we don't have the start of the next span, then use the end of the
2528 // predicates, but that means we miss comments.
2529 let len = where_clause.predicates.len();
2530 let end_of_preds = where_clause.predicates[len - 1].span().hi();
2531 let span_end = span_end.unwrap_or(end_of_preds);
2532 let items = itemize_list(
2533 context.snippet_provider,
2534 where_clause.predicates.iter(),
2537 |pred| pred.span().lo(),
2538 |pred| pred.span().hi(),
2539 |pred| pred.rewrite(context, Shape::legacy(budget, offset)),
2544 let item_vec = items.collect::<Vec<_>>();
2545 // FIXME: we don't need to collect here
2546 let tactic = definitive_tactic(&item_vec, ListTactic::Vertical, Separator::Comma, budget);
2548 let mut comma_tactic = context.config.trailing_comma();
2549 // Kind of a hack because we don't usually have trailing commas in where clauses.
2550 if comma_tactic == SeparatorTactic::Vertical || where_clause_option.suppress_comma {
2551 comma_tactic = SeparatorTactic::Never;
2554 let fmt = ListFormatting {
2557 trailing_separator: comma_tactic,
2558 separator_place: SeparatorPlace::Back,
2559 shape: Shape::legacy(budget, offset),
2560 ends_with_newline: tactic.ends_with_newline(context.config.indent_style()),
2561 preserve_newline: true,
2562 config: context.config,
2564 let preds_str = write_list(&item_vec, &fmt)?;
2566 let end_length = if terminator == "{" {
2567 // If the brace is on the next line we don't need to count it otherwise it needs two
2570 BraceStyle::AlwaysNextLine | BraceStyle::SameLineWhere => 0,
2571 BraceStyle::PreferSameLine => 2,
2573 } else if terminator == "=" {
2578 if density == Density::Tall || preds_str.contains('\n')
2579 || shape.indent.width() + " where ".len() + preds_str.len() + end_length > shape.width
2583 (shape.indent + extra_indent).to_string(context.config),
2587 Some(format!(" where {}", preds_str))
2591 fn missing_span_before_after_where(
2592 before_item_span_end: BytePos,
2593 where_clause: &ast::WhereClause,
2595 let missing_span_before = mk_sp(before_item_span_end, where_clause.span.lo());
2597 let pos_after_where = where_clause.span.lo() + BytePos(5);
2598 let missing_span_after = mk_sp(pos_after_where, where_clause.predicates[0].span().lo());
2599 (missing_span_before, missing_span_after)
2602 fn rewrite_comments_before_after_where(
2603 context: &RewriteContext,
2604 span_before_where: Span,
2605 span_after_where: Span,
2607 ) -> Option<(String, String)> {
2608 let before_comment = rewrite_missing_comment(span_before_where, shape, context)?;
2609 let after_comment = rewrite_missing_comment(
2611 shape.block_indent(context.config.tab_spaces()),
2614 Some((before_comment, after_comment))
2617 fn format_header(item_name: &str, ident: ast::Ident, vis: &ast::Visibility) -> String {
2618 format!("{}{}{}", format_visibility(vis), item_name, ident)
2621 #[derive(PartialEq, Eq, Clone, Copy)]
2629 context: &RewriteContext,
2630 generics: &ast::Generics,
2631 brace_style: BraceStyle,
2632 brace_pos: BracePos,
2636 ) -> Option<String> {
2637 let shape = Shape::legacy(context.budget(used_width + offset.width()), offset);
2638 let mut result = rewrite_generics(context, "", generics, shape, span)?;
2640 let same_line_brace = if !generics.where_clause.predicates.is_empty() || result.contains('\n') {
2641 let budget = context.budget(last_line_used_width(&result, offset.width()));
2642 let mut option = WhereClauseOption::snuggled(&result);
2643 if brace_pos == BracePos::None {
2644 option.suppress_comma = true;
2646 // If the generics are not parameterized then generics.span.hi() == 0,
2647 // so we use span.lo(), which is the position after `struct Foo`.
2648 let span_end_before_where = if generics.is_parameterized() {
2653 let where_clause_str = rewrite_where_clause(
2655 &generics.where_clause,
2657 Shape::legacy(budget, offset.block_only()),
2661 span_end_before_where,
2665 result.push_str(&where_clause_str);
2666 brace_pos == BracePos::ForceSameLine || brace_style == BraceStyle::PreferSameLine
2667 || (generics.where_clause.predicates.is_empty()
2668 && trimmed_last_line_width(&result) == 1)
2670 brace_pos == BracePos::ForceSameLine || trimmed_last_line_width(&result) == 1
2671 || brace_style != BraceStyle::AlwaysNextLine
2673 if brace_pos == BracePos::None {
2674 return Some(result);
2676 let total_used_width = last_line_used_width(&result, used_width);
2677 let remaining_budget = context.budget(total_used_width);
2678 // If the same line brace if forced, it indicates that we are rewriting an item with empty body,
2679 // and hence we take the closer into account as well for one line budget.
2680 // We assume that the closer has the same length as the opener.
2681 let overhead = if brace_pos == BracePos::ForceSameLine {
2688 let forbid_same_line_brace = overhead > remaining_budget;
2689 if !forbid_same_line_brace && same_line_brace {
2693 result.push_str(&offset.block_only().to_string(context.config));
2700 impl Rewrite for ast::ForeignItem {
2701 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
2702 let attrs_str = self.attrs.rewrite(context, shape)?;
2703 // Drop semicolon or it will be interpreted as comment.
2704 // FIXME: this may be a faulty span from libsyntax.
2705 let span = mk_sp(self.span.lo(), self.span.hi() - BytePos(1));
2707 let item_str = match self.node {
2708 ast::ForeignItemKind::Fn(ref fn_decl, ref generics) => {
2713 &FnSig::new(fn_decl, generics, self.vis.clone()),
2717 ).map(|(s, _)| format!("{};", s))
2719 ast::ForeignItemKind::Static(ref ty, is_mutable) => {
2720 // FIXME(#21): we're dropping potential comments in between the
2721 // function keywords here.
2722 let vis = format_visibility(&self.vis);
2723 let mut_str = if is_mutable { "mut " } else { "" };
2724 let prefix = format!("{}static {}{}:", vis, mut_str, self.ident);
2726 rewrite_assign_rhs(context, prefix, &**ty, shape.sub_width(1)?).map(|s| s + ";")
2728 ast::ForeignItemKind::Ty => {
2729 let vis = format_visibility(&self.vis);
2730 Some(format!("{}type {};", vis, self.ident))
2732 ast::ForeignItemKind::Macro(ref mac) => {
2733 rewrite_macro(mac, None, context, shape, MacroPosition::Item)
2737 let missing_span = if self.attrs.is_empty() {
2738 mk_sp(self.span.lo(), self.span.lo())
2740 mk_sp(self.attrs[self.attrs.len() - 1].span.hi(), self.span.lo())
2742 combine_strs_with_missing_comments(
2753 impl Rewrite for ast::GenericParam {
2754 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
2756 ast::GenericParam::Lifetime(ref lifetime_def) => lifetime_def.rewrite(context, shape),
2757 ast::GenericParam::Type(ref ty) => ty.rewrite(context, shape),
2762 /// Rewrite an inline mod.
2763 pub fn rewrite_mod(item: &ast::Item) -> String {
2764 let mut result = String::with_capacity(32);
2765 result.push_str(&*format_visibility(&item.vis));
2766 result.push_str("mod ");
2767 result.push_str(&item.ident.to_string());
2772 /// Rewrite `extern crate foo;` WITHOUT attributes.
2773 pub fn rewrite_extern_crate(context: &RewriteContext, item: &ast::Item) -> Option<String> {
2774 assert!(is_extern_crate(item));
2775 let new_str = context.snippet(item.span);
2776 Some(if contains_comment(new_str) {
2779 let no_whitespace = &new_str.split_whitespace().collect::<Vec<&str>>().join(" ");
2780 String::from(&*Regex::new(r"\s;").unwrap().replace(no_whitespace, ";"))
2784 /// Returns true for `mod foo;`, false for `mod foo { .. }`.
2785 pub fn is_mod_decl(item: &ast::Item) -> bool {
2787 ast::ItemKind::Mod(ref m) => m.inner.hi() != item.span.hi(),
2792 pub fn is_use_item(item: &ast::Item) -> bool {
2794 ast::ItemKind::Use(_) => true,
2799 pub fn is_extern_crate(item: &ast::Item) -> bool {
2801 ast::ItemKind::ExternCrate(..) => true,