src/items.rs

   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.
   4 //
   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.
  10
  11 // Formatting top-level items - functions, structs, enums, traits, impls.
  12
  13 use {ReturnIndent, BraceStyle};
  14 use utils::make_indent;
  15 use lists::{write_list, ListFormatting, SeparatorTactic, ListTactic};
  16 use visitor::FmtVisitor;
  17 use syntax::{ast, abi};
  18 use syntax::codemap::{self, Span, BytePos};
  19 use syntax::print::pprust;
  20 use syntax::parse::token;
  21
  22 impl<'a> FmtVisitor<'a> {
  23     pub fn rewrite_fn(&mut self,
  24                       indent: usize,
  25                       ident: ast::Ident,
  26                       fd: &ast::FnDecl,
  27                       explicit_self: Option<&ast::ExplicitSelf>,
  28                       generics: &ast::Generics,
  29                       unsafety: &ast::Unsafety,
  30                       constness: &ast::Constness,
  31                       abi: &abi::Abi,
  32                       vis: ast::Visibility,
  33                       span_end: BytePos)
  34         -> String
  35     {
  36         let newline_brace = self.newline_for_brace(&generics.where_clause);
  37
  38         let mut result = self.rewrite_fn_base(indent,
  39                                               ident,
  40                                               fd,
  41                                               explicit_self,
  42                                               generics,
  43                                               unsafety,
  44                                               constness,
  45                                               abi,
  46                                               vis,
  47                                               span_end,
  48                                               newline_brace);
  49
  50         // Prepare for the function body by possibly adding a newline and indent.
  51         // FIXME we'll miss anything between the end of the signature and the start
  52         // of the body, but we need more spans from the compiler to solve this.
  53         if newline_brace {
  54             result.push('\n');
  55             result.push_str(&make_indent(indent));
  56         } else {
  57             result.push(' ');
  58         }
  59
  60         result
  61     }
  62
  63     pub fn rewrite_required_fn(&mut self,
  64                                indent: usize,
  65                                ident: ast::Ident,
  66                                sig: &ast::MethodSig,
  67                                span: Span)
  68         -> String
  69     {
  70         // Drop semicolon or it will be interpreted as comment
  71         let span_end = span.hi - BytePos(1);
  72
  73         let mut result = self.rewrite_fn_base(indent,
  74                                               ident,
  75                                               &sig.decl,
  76                                               Some(&sig.explicit_self),
  77                                               &sig.generics,
  78                                               &sig.unsafety,
  79                                               &sig.constness,
  80                                               &sig.abi,
  81                                               ast::Visibility::Inherited,
  82                                               span_end,
  83                                               false);
  84
  85         // Re-attach semicolon
  86         result.push(';');
  87
  88         result
  89     }
  90
  91     fn rewrite_fn_base(&mut self,
  92                        indent: usize,
  93                        ident: ast::Ident,
  94                        fd: &ast::FnDecl,
  95                        explicit_self: Option<&ast::ExplicitSelf>,
  96                        generics: &ast::Generics,
  97                        unsafety: &ast::Unsafety,
  98                        constness: &ast::Constness,
  99                        abi: &abi::Abi,
 100                        vis: ast::Visibility,
 101                        span_end: BytePos,
 102                        newline_brace: bool)
 103         -> String
 104     {
 105         // FIXME we'll lose any comments in between parts of the function decl, but anyone
 106         // who comments there probably deserves what they get.
 107
 108         let where_clause = &generics.where_clause;
 109
 110         let mut result = String::with_capacity(1024);
 111         // Vis unsafety abi.
 112         if vis == ast::Visibility::Public {
 113             result.push_str("pub ");
 114         }
 115         if let &ast::Unsafety::Unsafe = unsafety {
 116             result.push_str("unsafe ");
 117         }
 118         if let &ast::Constness::Const = constness {
 119             result.push_str("const ");
 120         }
 121         if *abi != abi::Rust {
 122             result.push_str("extern ");
 123             result.push_str(&abi.to_string());
 124             result.push(' ');
 125         }
 126
 127         // fn foo
 128         result.push_str("fn ");
 129         result.push_str(&token::get_ident(ident));
 130
 131         // Generics.
 132         let generics_indent = indent + result.len();
 133         result.push_str(&self.rewrite_generics(generics,
 134                                                generics_indent,
 135                                                span_for_return(&fd.output).lo));
 136
 137         let ret_str = self.rewrite_return(&fd.output);
 138
 139         // Args.
 140         let (one_line_budget, multi_line_budget, arg_indent) =
 141             self.compute_budgets_for_args(&mut result, indent, ret_str.len(), newline_brace);
 142
 143         debug!("rewrite_fn: one_line_budget: {}, multi_line_budget: {}, arg_indent: {}",
 144                one_line_budget, multi_line_budget, arg_indent);
 145
 146         result.push('(');
 147         result.push_str(&self.rewrite_args(&fd.inputs,
 148                                            explicit_self,
 149                                            one_line_budget,
 150                                            multi_line_budget,
 151                                            arg_indent,
 152                                            span_for_return(&fd.output)));
 153         result.push(')');
 154
 155         // Return type.
 156         if ret_str.len() > 0 {
 157             // If we've already gone multi-line, or the return type would push
 158             // over the max width, then put the return type on a new line.
 159             if result.contains("\n") ||
 160                result.len() + indent + ret_str.len() > config!(max_width) {
 161                 let indent = match config!(fn_return_indent) {
 162                     ReturnIndent::WithWhereClause => indent + 4,
 163                     // TODO we might want to check that using the arg indent doesn't
 164                     // blow our budget, and if it does, then fallback to the where
 165                     // clause indent.
 166                     _ => arg_indent,
 167                 };
 168
 169                 result.push('\n');
 170                 result.push_str(&make_indent(indent));
 171             } else {
 172                 result.push(' ');
 173             }
 174             result.push_str(&ret_str);
 175
 176             // Comment between return type and the end of the decl.
 177             let snippet_lo = fd.output.span().hi;
 178             if where_clause.predicates.len() == 0 {
 179                 let snippet_hi = span_end;
 180                 let snippet = self.snippet(codemap::mk_sp(snippet_lo, snippet_hi));
 181                 let snippet = snippet.trim();
 182                 if snippet.len() > 0 {
 183                     result.push(' ');
 184                     result.push_str(snippet);
 185                 }
 186             } else {
 187                 // FIXME it would be nice to catch comments between the return type
 188                 // and the where clause, but we don't have a span for the where
 189                 // clause.
 190             }
 191         }
 192
 193         // Where clause.
 194         result.push_str(&self.rewrite_where_clause(where_clause, indent, span_end));
 195
 196         result
 197     }
 198
 199     fn rewrite_args(&self,
 200                     args: &[ast::Arg],
 201                     explicit_self: Option<&ast::ExplicitSelf>,
 202                     one_line_budget: usize,
 203                     multi_line_budget: usize,
 204                     arg_indent: usize,
 205                     ret_span: Span)
 206         -> String
 207     {
 208         let mut arg_item_strs: Vec<_> = args.iter().map(|a| self.rewrite_fn_input(a)).collect();
 209         // Account for sugary self.
 210         let mut min_args = 1;
 211         if let Some(explicit_self) = explicit_self {
 212             match explicit_self.node {
 213                 ast::ExplicitSelf_::SelfRegion(ref lt, ref m, _) => {
 214                     let lt_str = match lt {
 215                         &Some(ref l) => format!("{} ", pprust::lifetime_to_string(l)),
 216                         &None => String::new(),
 217                     };
 218                     let mut_str = match m {
 219                         &ast::Mutability::MutMutable => "mut ".to_owned(),
 220                         &ast::Mutability::MutImmutable => String::new(),
 221                     };
 222                     arg_item_strs[0] = format!("&{}{}self", lt_str, mut_str);
 223                     min_args = 2;
 224                 }
 225                 ast::ExplicitSelf_::SelfExplicit(ref ty, _) => {
 226                     arg_item_strs[0] = format!("self: {}", pprust::ty_to_string(ty));
 227                 }
 228                 ast::ExplicitSelf_::SelfValue(_) => {
 229                     assert!(args.len() >= 1, "&[ast::Arg] shouldn't be empty.");
 230
 231                     // this hacky solution caused by absence of `Mutability` in `SelfValue`.
 232                     let mut_str = {
 233                         if let ast::Pat_::PatIdent(ast::BindingMode::BindByValue(mutability), _, _)
 234                                 = args[0].pat.node {
 235                             match mutability {
 236                                 ast::Mutability::MutMutable => "mut ",
 237                                 ast::Mutability::MutImmutable => "",
 238                             }
 239                         } else {
 240                             panic!("there is a bug or change in structure of AST, aborting.");
 241                         }
 242                     };
 243
 244                     arg_item_strs[0] = format!("{}self", mut_str);
 245                     min_args = 2;
 246                 }
 247                 _ => {}
 248             }
 249         }
 250
 251         // Comments between args
 252         let mut arg_comments = Vec::new();
 253         if min_args == 2 {
 254             arg_comments.push("".to_owned());
 255         }
 256         // TODO if there are no args, there might still be a comment, but without
 257         // spans for the comment or parens, there is no chance of getting it right.
 258         // You also don't get to put a comment on self, unless it is explicit.
 259         if args.len() >= min_args {
 260             arg_comments = self.make_comments_for_list(arg_comments,
 261                                                        args[min_args-1..].iter(),
 262                                                        ",",
 263                                                        ")",
 264                                                        |arg| arg.pat.span.lo,
 265                                                        |arg| arg.ty.span.hi,
 266                                                        ret_span.lo);
 267         }
 268
 269         debug!("comments: {:?}", arg_comments);
 270
 271         // If there are // comments, keep them multi-line.
 272         let mut list_tactic = ListTactic::HorizontalVertical;
 273         if arg_comments.iter().any(|c| c.contains("//")) {
 274             list_tactic = ListTactic::Vertical;
 275         }
 276
 277         assert_eq!(arg_item_strs.len(), arg_comments.len());
 278         let arg_strs: Vec<_> = arg_item_strs.into_iter().zip(arg_comments.into_iter()).collect();
 279
 280         let fmt = ListFormatting {
 281             tactic: list_tactic,
 282             separator: ",",
 283             trailing_separator: SeparatorTactic::Never,
 284             indent: arg_indent,
 285             h_width: one_line_budget,
 286             v_width: multi_line_budget,
 287         };
 288
 289         write_list(&arg_strs, &fmt)
 290     }
 291
 292     // Gets comments in between items of a list.
 293     fn make_comments_for_list<T, I, F1, F2>(&self,
 294                                             prefix: Vec<String>,
 295                                             mut it: I,
 296                                             separator: &str,
 297                                             terminator: &str,
 298                                             get_lo: F1,
 299                                             get_hi: F2,
 300                                             next_span_start: BytePos)
 301         -> Vec<String>
 302         where I: Iterator<Item=T>,
 303               F1: Fn(&T) -> BytePos,
 304               F2: Fn(&T) -> BytePos
 305     {
 306         let mut result = prefix;
 307
 308         let mut prev_end = get_hi(&it.next().unwrap());
 309         for item in it {
 310             let cur_start = get_lo(&item);
 311             let snippet = self.snippet(codemap::mk_sp(prev_end, cur_start));
 312             let mut snippet = snippet.trim();
 313             let white_space: &[_] = &[' ', '\t'];
 314             if snippet.starts_with(separator) {
 315                 snippet = snippet[separator.len()..].trim_matches(white_space);
 316             } else if snippet.ends_with(separator) {
 317                 snippet = snippet[..snippet.len()-separator.len()].trim_matches(white_space);
 318             }
 319             result.push(snippet.to_owned());
 320             prev_end = get_hi(&item);
 321         }
 322         // Get the last commment.
 323         // FIXME If you thought the crap with the commas was ugly, just wait.
 324         // This is awful. We're going to look from the last item span to the
 325         // start of the return type span, then we drop everything after the
 326         // first closing paren. Obviously, this will break if there is a
 327         // closing paren in the comment.
 328         // The fix is comments in the AST or a span for the closing paren.
 329         let snippet = self.snippet(codemap::mk_sp(prev_end, next_span_start));
 330         let snippet = snippet.trim();
 331         let snippet = &snippet[..snippet.find(terminator)
 332                                     .unwrap_or(snippet.find(separator).unwrap_or(snippet.len()))];
 333         let snippet = snippet.trim();
 334         result.push(snippet.to_owned());
 335
 336         result
 337     }
 338
 339     fn compute_budgets_for_args(&self,
 340                                 result: &mut String,
 341                                 indent: usize,
 342                                 ret_str_len: usize,
 343                                 newline_brace: bool)
 344         -> (usize, usize, usize)
 345     {
 346         let mut budgets = None;
 347
 348         // Try keeping everything on the same line
 349         if !result.contains("\n") {
 350             // 3 = `() `, space is before ret_string
 351             let mut used_space = indent + result.len() + ret_str_len + 3;
 352             if !newline_brace {
 353                 used_space += 2;
 354             }
 355             let one_line_budget = if used_space > config!(max_width) {
 356                 0
 357             } else {
 358                 config!(max_width) - used_space
 359             };
 360
 361             // 2 = `()`
 362             let used_space = indent + result.len() + 2;
 363             let max_space = config!(ideal_width) + config!(leeway);
 364             debug!("compute_budgets_for_args: used_space: {}, max_space: {}",
 365                    used_space, max_space);
 366             if used_space < max_space {
 367                 budgets = Some((one_line_budget,
 368                                 max_space - used_space,
 369                                 indent + result.len() + 1));
 370             }
 371         }
 372
 373         // Didn't work. we must force vertical layout and put args on a newline.
 374         if let None = budgets {
 375             result.push('\n');
 376             result.push_str(&make_indent(indent + 4));
 377             // 6 = new indent + `()`
 378             let used_space = indent + 6;
 379             let max_space = config!(ideal_width) + config!(leeway);
 380             if used_space > max_space {
 381                 // Whoops! bankrupt.
 382                 // TODO take evasive action, perhaps kill the indent or something.
 383             } else {
 384                 // 5 = new indent + `(`
 385                 budgets = Some((0, max_space - used_space, indent + 5));
 386             }
 387         }
 388
 389         budgets.unwrap()
 390     }
 391
 392     fn newline_for_brace(&self, where_clause: &ast::WhereClause) -> bool {
 393         match config!(fn_brace_style) {
 394             BraceStyle::AlwaysNextLine => true,
 395             BraceStyle::SameLineWhere if where_clause.predicates.len() > 0 => true,
 396             _ => false,
 397         }
 398     }
 399
 400     pub fn visit_struct(&mut self,
 401                         ident: ast::Ident,
 402                         vis: ast::Visibility,
 403                         struct_def: &ast::StructDef,
 404                         generics: &ast::Generics,
 405                         span: Span)
 406     {
 407         let header_str = self.struct_header(ident, vis);
 408         self.changes.push_str_span(span, &header_str);
 409
 410         if struct_def.fields.len() == 0 {
 411             assert!(generics.where_clause.predicates.len() == 0,
 412                     "No-field struct with where clause?");
 413             assert!(generics.lifetimes.len() == 0, "No-field struct with generics?");
 414             assert!(generics.ty_params.len() == 0, "No-field struct with generics?");
 415
 416             self.changes.push_str_span(span, ";");
 417             return;
 418         }
 419
 420         let mut generics_buf = String::new();
 421         let generics_str = self.rewrite_generics(generics, self.block_indent, struct_def.fields[0].span.lo);
 422         generics_buf.push_str(&generics_str);
 423
 424         if generics.where_clause.predicates.len() > 0 {
 425             generics_buf.push_str(&self.rewrite_where_clause(&generics.where_clause,
 426                                                              self.block_indent,
 427                                                              struct_def.fields[0].span.lo));
 428             generics_buf.push_str(&make_indent(self.block_indent));
 429             generics_buf.push_str("\n{");
 430
 431         } else {
 432             generics_buf.push_str(" {");
 433         }
 434         self.changes.push_str_span(span, &generics_buf);
 435
 436         let struct_snippet = self.snippet(span);
 437         // FIXME this will give incorrect results if there is a { in a commet.
 438         self.last_pos = span.lo + BytePos(struct_snippet.find('{').unwrap() as u32 + 1);
 439
 440         self.block_indent += config!(tab_spaces);
 441         for (i, f) in struct_def.fields.iter().enumerate() {
 442             self.visit_field(f, i == struct_def.fields.len() - 1, span.lo, &struct_snippet);
 443         }
 444         self.block_indent -= config!(tab_spaces);
 445
 446         self.format_missing_with_indent(span.lo + BytePos(struct_snippet.rfind('}').unwrap() as u32));
 447         self.changes.push_str_span(span, "}");
 448     }
 449
 450     fn struct_header(&self,
 451                      ident: ast::Ident,
 452                      vis: ast::Visibility)
 453         -> String
 454     {
 455         let vis = if vis == ast::Visibility::Public {
 456             "pub "
 457         } else {
 458             ""
 459         };
 460
 461         format!("{}struct {}", vis, &token::get_ident(ident))
 462     }
 463
 464     // Field of a struct
 465     fn visit_field(&mut self,
 466                    field: &ast::StructField,
 467                    last_field: bool,
 468                    // These two args are for missing spans hacks.
 469                    struct_start: BytePos,
 470                    struct_snippet: &str)
 471     {
 472         if self.visit_attrs(&field.node.attrs) {
 473             return;
 474         }
 475         self.format_missing_with_indent(field.span.lo);
 476
 477         let name = match field.node.kind {
 478             ast::StructFieldKind::NamedField(ident, _) => Some(token::get_ident(ident)),
 479             ast::StructFieldKind::UnnamedField(_) => None,
 480         };
 481         let vis = match field.node.kind {
 482             ast::StructFieldKind::NamedField(_, vis) |
 483             ast::StructFieldKind::UnnamedField(vis) => if vis == ast::Visibility::Public {
 484                 "pub "
 485             } else {
 486                 ""
 487             }
 488         };
 489         let typ = pprust::ty_to_string(&field.node.ty);
 490
 491         let mut field_str = match name {
 492             Some(name) => {
 493                 let budget = config!(ideal_width) - self.block_indent;
 494                 // 3 is being conservative and assuming that there will be a trailing comma.
 495                 if self.block_indent + vis.len() + name.len() + typ.len() + 3 > budget {
 496                     format!("{}{}:\n{}{}",
 497                             vis,
 498                             name,
 499                             &make_indent(self.block_indent + config!(tab_spaces)),
 500                             typ)
 501                 } else {
 502                     format!("{}{}: {}", vis, name, typ)
 503                 }
 504             }
 505             None => format!("{}{}", vis, typ),
 506         };
 507         if !last_field || config!(struct_trailing_comma) {
 508             field_str.push(',');
 509         }
 510         self.changes.push_str_span(field.span, &field_str);
 511
 512         // This hack makes sure we only add comments etc. after the comma, and
 513         // makes sure we don't repeat any commas.
 514         let hi = field.span.hi;
 515         // FIXME a comma in a comment will break this hack.
 516         let comma_pos = match struct_snippet[(hi.0 - struct_start.0) as usize..].find(',') {
 517             Some(i) => i,
 518             None => 0,
 519         };
 520         self.last_pos = hi + BytePos(comma_pos as u32 + 1);
 521     }
 522
 523     fn rewrite_generics(&self, generics: &ast::Generics, indent: usize, span_end: BytePos) -> String {
 524         // FIXME convert bounds to where clauses where they get too big or if
 525         // there is a where clause at all.
 526         let mut result = String::new();
 527         let lifetimes: &[_] = &generics.lifetimes;
 528         let tys: &[_] = &generics.ty_params;
 529         if lifetimes.len() + tys.len() == 0 {
 530             return result;
 531         }
 532
 533         let budget = config!(max_width) - indent - 2;
 534         // TODO might need to insert a newline if the generics are really long
 535         result.push('<');
 536
 537         // Strings for the generics.
 538         let lt_strs = lifetimes.iter().map(|l| self.rewrite_lifetime_def(l));
 539         let ty_strs = tys.iter().map(|ty| self.rewrite_ty_param(ty));
 540
 541         // Extract comments between generics.
 542         let lt_spans = lifetimes.iter().map(|l| {
 543             let hi = if l.bounds.len() == 0 {
 544                 l.lifetime.span.hi
 545             } else {
 546                 l.bounds[l.bounds.len() - 1].span.hi
 547             };
 548             codemap::mk_sp(l.lifetime.span.lo, hi)
 549         });
 550         let ty_spans = tys.iter().map(span_for_ty_param);
 551         let comments = self.make_comments_for_list(Vec::new(),
 552                                                    lt_spans.chain(ty_spans),
 553                                                    ",",
 554                                                    ">",
 555                                                    |sp| sp.lo,
 556                                                    |sp| sp.hi,
 557                                                    span_end);
 558
 559         // If there are // comments, keep them multi-line.
 560         let mut list_tactic = ListTactic::HorizontalVertical;
 561         if comments.iter().any(|c| c.contains("//")) {
 562             list_tactic = ListTactic::Vertical;
 563         }
 564
 565         let generics_strs: Vec<_> = lt_strs.chain(ty_strs).zip(comments.into_iter()).collect();
 566         let fmt = ListFormatting {
 567             tactic: list_tactic,
 568             separator: ",",
 569             trailing_separator: SeparatorTactic::Never,
 570             indent: indent + 1,
 571             h_width: budget,
 572             v_width: budget,
 573         };
 574         result.push_str(&write_list(&generics_strs, &fmt));
 575
 576         result.push('>');
 577
 578         result
 579     }
 580
 581     fn rewrite_where_clause(&self,
 582                             where_clause: &ast::WhereClause,
 583                             indent: usize,
 584                             span_end: BytePos)
 585         -> String
 586     {
 587         let mut result = String::new();
 588         if where_clause.predicates.len() == 0 {
 589             return result;
 590         }
 591
 592         result.push('\n');
 593         result.push_str(&make_indent(indent + 4));
 594         result.push_str("where ");
 595
 596         let comments = self.make_comments_for_list(Vec::new(),
 597                                                    where_clause.predicates.iter(),
 598                                                    ",",
 599                                                    "{",
 600                                                    |pred| span_for_where_pred(pred).lo,
 601                                                    |pred| span_for_where_pred(pred).hi,
 602                                                    span_end);
 603
 604         let where_strs: Vec<_> = where_clause.predicates.iter()
 605                                                         .map(|p| (self.rewrite_pred(p)))
 606                                                         .zip(comments.into_iter())
 607                                                         .collect();
 608
 609         let budget = config!(ideal_width) + config!(leeway) - indent - 10;
 610         let fmt = ListFormatting {
 611             tactic: ListTactic::Vertical,
 612             separator: ",",
 613             trailing_separator: SeparatorTactic::Never,
 614             indent: indent + 10,
 615             h_width: budget,
 616             v_width: budget,
 617         };
 618         result.push_str(&write_list(&where_strs, &fmt));
 619
 620         result
 621     }
 622
 623     fn rewrite_return(&self, ret: &ast::FunctionRetTy) -> String {
 624         match *ret {
 625             ast::FunctionRetTy::DefaultReturn(_) => String::new(),
 626             ast::FunctionRetTy::NoReturn(_) => "-> !".to_owned(),
 627             ast::FunctionRetTy::Return(ref ty) => "-> ".to_owned() + &pprust::ty_to_string(ty),
 628         }
 629     }
 630
 631     // TODO we farm this out, but this could spill over the column limit, so we ought to handle it properly
 632     fn rewrite_fn_input(&self, arg: &ast::Arg) -> String {
 633         format!("{}: {}",
 634                 pprust::pat_to_string(&arg.pat),
 635                 pprust::ty_to_string(&arg.ty))
 636     }
 637 }
 638
 639 fn span_for_return(ret: &ast::FunctionRetTy) -> Span {
 640     match *ret {
 641         ast::FunctionRetTy::NoReturn(ref span) |
 642         ast::FunctionRetTy::DefaultReturn(ref span) => span.clone(),
 643         ast::FunctionRetTy::Return(ref ty) => ty.span,
 644     }
 645 }
 646
 647 fn span_for_ty_param(ty: &ast::TyParam) -> Span {
 648     // Note that ty.span is the span for ty.ident, not the whole item.
 649     let lo = ty.span.lo;
 650     if let Some(ref def) = ty.default {
 651         return codemap::mk_sp(lo, def.span.hi);
 652     }
 653     if ty.bounds.len() == 0 {
 654         return ty.span;
 655     }
 656     let hi = match ty.bounds[ty.bounds.len() - 1] {
 657         ast::TyParamBound::TraitTyParamBound(ref ptr, _) => ptr.span.hi,
 658         ast::TyParamBound::RegionTyParamBound(ref l) => l.span.hi,
 659     };
 660     codemap::mk_sp(lo, hi)
 661 }
 662
 663 fn span_for_where_pred(pred: &ast::WherePredicate) -> Span {
 664     match *pred {
 665         ast::WherePredicate::BoundPredicate(ref p) => p.span,
 666         ast::WherePredicate::RegionPredicate(ref p) => p.span,
 667         ast::WherePredicate::EqPredicate(ref p) => p.span,
 668     }
 669 }