src/libsyntax/print/pprust.rs

   1 use rustc_target::spec::abi::{self, Abi};
   2 use ast::{self, BlockCheckMode, PatKind, RangeEnd, RangeSyntax};
   3 use ast::{SelfKind, GenericBound, TraitBoundModifier};
   4 use ast::{Attribute, MacDelimiter, GenericArg};
   5 use util::parser::{self, AssocOp, Fixity};
   6 use attr;
   7 use source_map::{self, SourceMap, Spanned};
   8 use syntax_pos::{self, BytePos};
   9 use parse::token::{self, BinOpToken, Token};
  10 use parse::lexer::comments;
  11 use parse::{self, ParseSess};
  12 use print::pp::{self, Breaks};
  13 use print::pp::Breaks::{Consistent, Inconsistent};
  14 use ptr::P;
  15 use std_inject;
  16 use symbol::keywords;
  17 use syntax_pos::{DUMMY_SP, FileName};
  18 use tokenstream::{self, TokenStream, TokenTree};
  19
  20 use std::ascii;
  21 use std::borrow::Cow;
  22 use std::io::{self, Write, Read};
  23 use std::iter::Peekable;
  24 use std::vec;
  25
  26 pub enum AnnNode<'a> {
  27     Ident(&'a ast::Ident),
  28     Name(&'a ast::Name),
  29     Block(&'a ast::Block),
  30     Item(&'a ast::Item),
  31     SubItem(ast::NodeId),
  32     Expr(&'a ast::Expr),
  33     Pat(&'a ast::Pat),
  34 }
  35
  36 pub trait PpAnn {
  37     fn pre(&self, _state: &mut State, _node: AnnNode) -> io::Result<()> { Ok(()) }
  38     fn post(&self, _state: &mut State, _node: AnnNode) -> io::Result<()> { Ok(()) }
  39 }
  40
  41 #[derive(Copy, Clone)]
  42 pub struct NoAnn;
  43
  44 impl PpAnn for NoAnn {}
  45
  46 pub struct State<'a> {
  47     pub s: pp::Printer<'a>,
  48     cm: Option<&'a SourceMap>,
  49     comments: Option<Vec<comments::Comment> >,
  50     literals: Peekable<vec::IntoIter<comments::Literal>>,
  51     cur_cmnt: usize,
  52     boxes: Vec<pp::Breaks>,
  53     ann: &'a (dyn PpAnn+'a),
  54     is_expanded: bool
  55 }
  56
  57 fn rust_printer<'a>(writer: Box<dyn Write+'a>, ann: &'a dyn PpAnn) -> State<'a> {
  58     State {
  59         s: pp::mk_printer(writer, DEFAULT_COLUMNS),
  60         cm: None,
  61         comments: None,
  62         literals: vec![].into_iter().peekable(),
  63         cur_cmnt: 0,
  64         boxes: Vec::new(),
  65         ann,
  66         is_expanded: false
  67     }
  68 }
  69
  70 pub const INDENT_UNIT: usize = 4;
  71
  72 pub const DEFAULT_COLUMNS: usize = 78;
  73
  74 /// Requires you to pass an input filename and reader so that
  75 /// it can scan the input text for comments and literals to
  76 /// copy forward.
  77 pub fn print_crate<'a>(cm: &'a SourceMap,
  78                        sess: &ParseSess,
  79                        krate: &ast::Crate,
  80                        filename: FileName,
  81                        input: &mut dyn Read,
  82                        out: Box<dyn Write+'a>,
  83                        ann: &'a dyn PpAnn,
  84                        is_expanded: bool) -> io::Result<()> {
  85     let mut s = State::new_from_input(cm, sess, filename, input, out, ann, is_expanded);
  86
  87     if is_expanded && std_inject::injected_crate_name().is_some() {
  88         // We need to print `#![no_std]` (and its feature gate) so that
  89         // compiling pretty-printed source won't inject libstd again.
  90         // However we don't want these attributes in the AST because
  91         // of the feature gate, so we fake them up here.
  92
  93         // #![feature(prelude_import)]
  94         let pi_nested = attr::mk_nested_word_item(ast::Ident::from_str("prelude_import"));
  95         let list = attr::mk_list_item(DUMMY_SP, ast::Ident::from_str("feature"), vec![pi_nested]);
  96         let fake_attr = attr::mk_attr_inner(DUMMY_SP, attr::mk_attr_id(), list);
  97         s.print_attribute(&fake_attr)?;
  98
  99         // #![no_std]
 100         let no_std_meta = attr::mk_word_item(ast::Ident::from_str("no_std"));
 101         let fake_attr = attr::mk_attr_inner(DUMMY_SP, attr::mk_attr_id(), no_std_meta);
 102         s.print_attribute(&fake_attr)?;
 103     }
 104
 105     s.print_mod(&krate.module, &krate.attrs)?;
 106     s.print_remaining_comments()?;
 107     s.s.eof()
 108 }
 109
 110 impl<'a> State<'a> {
 111     pub fn new_from_input(cm: &'a SourceMap,
 112                           sess: &ParseSess,
 113                           filename: FileName,
 114                           input: &mut dyn Read,
 115                           out: Box<dyn Write+'a>,
 116                           ann: &'a dyn PpAnn,
 117                           is_expanded: bool) -> State<'a> {
 118         let (cmnts, lits) = comments::gather_comments_and_literals(sess, filename, input);
 119
 120         State::new(
 121             cm,
 122             out,
 123             ann,
 124             Some(cmnts),
 125             // If the code is post expansion, don't use the table of
 126             // literals, since it doesn't correspond with the literals
 127             // in the AST anymore.
 128             if is_expanded { None } else { Some(lits) },
 129             is_expanded
 130         )
 131     }
 132
 133     pub fn new(cm: &'a SourceMap,
 134                out: Box<dyn Write+'a>,
 135                ann: &'a dyn PpAnn,
 136                comments: Option<Vec<comments::Comment>>,
 137                literals: Option<Vec<comments::Literal>>,
 138                is_expanded: bool) -> State<'a> {
 139         State {
 140             s: pp::mk_printer(out, DEFAULT_COLUMNS),
 141             cm: Some(cm),
 142             comments,
 143             literals: literals.unwrap_or_default().into_iter().peekable(),
 144             cur_cmnt: 0,
 145             boxes: Vec::new(),
 146             ann,
 147             is_expanded: is_expanded
 148         }
 149     }
 150 }
 151
 152 pub fn to_string<F>(f: F) -> String where
 153     F: FnOnce(&mut State) -> io::Result<()>,
 154 {
 155     let mut wr = Vec::new();
 156     {
 157         let ann = NoAnn;
 158         let mut printer = rust_printer(Box::new(&mut wr), &ann);
 159         f(&mut printer).unwrap();
 160         printer.s.eof().unwrap();
 161     }
 162     String::from_utf8(wr).unwrap()
 163 }
 164
 165 fn binop_to_string(op: BinOpToken) -> &'static str {
 166     match op {
 167         token::Plus     => "+",
 168         token::Minus    => "-",
 169         token::Star     => "*",
 170         token::Slash    => "/",
 171         token::Percent  => "%",
 172         token::Caret    => "^",
 173         token::And      => "&",
 174         token::Or       => "|",
 175         token::Shl      => "<<",
 176         token::Shr      => ">>",
 177     }
 178 }
 179
 180 pub fn token_to_string(tok: &Token) -> String {
 181     match *tok {
 182         token::Eq                   => "=".to_string(),
 183         token::Lt                   => "<".to_string(),
 184         token::Le                   => "<=".to_string(),
 185         token::EqEq                 => "==".to_string(),
 186         token::Ne                   => "!=".to_string(),
 187         token::Ge                   => ">=".to_string(),
 188         token::Gt                   => ">".to_string(),
 189         token::Not                  => "!".to_string(),
 190         token::Tilde                => "~".to_string(),
 191         token::OrOr                 => "||".to_string(),
 192         token::AndAnd               => "&&".to_string(),
 193         token::BinOp(op)            => binop_to_string(op).to_string(),
 194         token::BinOpEq(op)          => format!("{}=", binop_to_string(op)),
 195
 196         /* Structural symbols */
 197         token::At                   => "@".to_string(),
 198         token::Dot                  => ".".to_string(),
 199         token::DotDot               => "..".to_string(),
 200         token::DotDotDot            => "...".to_string(),
 201         token::DotDotEq             => "..=".to_string(),
 202         token::Comma                => ",".to_string(),
 203         token::Semi                 => ";".to_string(),
 204         token::Colon                => ":".to_string(),
 205         token::ModSep               => "::".to_string(),
 206         token::RArrow               => "->".to_string(),
 207         token::LArrow               => "<-".to_string(),
 208         token::FatArrow             => "=>".to_string(),
 209         token::OpenDelim(token::Paren) => "(".to_string(),
 210         token::CloseDelim(token::Paren) => ")".to_string(),
 211         token::OpenDelim(token::Bracket) => "[".to_string(),
 212         token::CloseDelim(token::Bracket) => "]".to_string(),
 213         token::OpenDelim(token::Brace) => "{".to_string(),
 214         token::CloseDelim(token::Brace) => "}".to_string(),
 215         token::OpenDelim(token::NoDelim) |
 216         token::CloseDelim(token::NoDelim) => " ".to_string(),
 217         token::Pound                => "#".to_string(),
 218         token::Dollar               => "$".to_string(),
 219         token::Question             => "?".to_string(),
 220         token::SingleQuote          => "'".to_string(),
 221
 222         /* Literals */
 223         token::Literal(lit, suf) => {
 224             let mut out = match lit {
 225                 token::Byte(b)           => format!("b'{}'", b),
 226                 token::Char(c)           => format!("'{}'", c),
 227                 token::Err(c)            => format!("'{}'", c),
 228                 token::Float(c)          |
 229                 token::Integer(c)        => c.to_string(),
 230                 token::Str_(s)           => format!("\"{}\"", s),
 231                 token::StrRaw(s, n)      => format!("r{delim}\"{string}\"{delim}",
 232                                                     delim="#".repeat(n as usize),
 233                                                     string=s),
 234                 token::ByteStr(v)         => format!("b\"{}\"", v),
 235                 token::ByteStrRaw(s, n)   => format!("br{delim}\"{string}\"{delim}",
 236                                                     delim="#".repeat(n as usize),
 237                                                     string=s),
 238             };
 239
 240             if let Some(s) = suf {
 241                 out.push_str(&s.as_str())
 242             }
 243
 244             out
 245         }
 246
 247         /* Name components */
 248         token::Ident(s, false)      => s.to_string(),
 249         token::Ident(s, true)       => format!("r#{}", s),
 250         token::Lifetime(s)          => s.to_string(),
 251
 252         /* Other */
 253         token::DocComment(s)        => s.to_string(),
 254         token::Eof                  => "<eof>".to_string(),
 255         token::Whitespace           => " ".to_string(),
 256         token::Comment              => "/* */".to_string(),
 257         token::Shebang(s)           => format!("/* shebang: {}*/", s),
 258
 259         token::Interpolated(ref nt) => match nt.0 {
 260             token::NtExpr(ref e)        => expr_to_string(e),
 261             token::NtMeta(ref e)        => meta_item_to_string(e),
 262             token::NtTy(ref e)          => ty_to_string(e),
 263             token::NtPath(ref e)        => path_to_string(e),
 264             token::NtItem(ref e)        => item_to_string(e),
 265             token::NtBlock(ref e)       => block_to_string(e),
 266             token::NtStmt(ref e)        => stmt_to_string(e),
 267             token::NtPat(ref e)         => pat_to_string(e),
 268             token::NtIdent(e, false)    => ident_to_string(e),
 269             token::NtIdent(e, true)     => format!("r#{}", ident_to_string(e)),
 270             token::NtLifetime(e)        => ident_to_string(e),
 271             token::NtLiteral(ref e)     => expr_to_string(e),
 272             token::NtTT(ref tree)       => tt_to_string(tree.clone()),
 273             token::NtArm(ref e)         => arm_to_string(e),
 274             token::NtImplItem(ref e)    => impl_item_to_string(e),
 275             token::NtTraitItem(ref e)   => trait_item_to_string(e),
 276             token::NtGenerics(ref e)    => generic_params_to_string(&e.params),
 277             token::NtWhereClause(ref e) => where_clause_to_string(e),
 278             token::NtArg(ref e)         => arg_to_string(e),
 279             token::NtVis(ref e)         => vis_to_string(e),
 280             token::NtForeignItem(ref e) => foreign_item_to_string(e),
 281         }
 282     }
 283 }
 284
 285 pub fn ty_to_string(ty: &ast::Ty) -> String {
 286     to_string(|s| s.print_type(ty))
 287 }
 288
 289 pub fn bounds_to_string(bounds: &[ast::GenericBound]) -> String {
 290     to_string(|s| s.print_type_bounds("", bounds))
 291 }
 292
 293 pub fn pat_to_string(pat: &ast::Pat) -> String {
 294     to_string(|s| s.print_pat(pat))
 295 }
 296
 297 pub fn arm_to_string(arm: &ast::Arm) -> String {
 298     to_string(|s| s.print_arm(arm))
 299 }
 300
 301 pub fn expr_to_string(e: &ast::Expr) -> String {
 302     to_string(|s| s.print_expr(e))
 303 }
 304
 305 pub fn lifetime_to_string(lt: &ast::Lifetime) -> String {
 306     to_string(|s| s.print_lifetime(*lt))
 307 }
 308
 309 pub fn tt_to_string(tt: tokenstream::TokenTree) -> String {
 310     to_string(|s| s.print_tt(tt))
 311 }
 312
 313 pub fn tts_to_string(tts: &[tokenstream::TokenTree]) -> String {
 314     to_string(|s| s.print_tts(tts.iter().cloned().collect()))
 315 }
 316
 317 pub fn tokens_to_string(tokens: TokenStream) -> String {
 318     to_string(|s| s.print_tts(tokens))
 319 }
 320
 321 pub fn stmt_to_string(stmt: &ast::Stmt) -> String {
 322     to_string(|s| s.print_stmt(stmt))
 323 }
 324
 325 pub fn attr_to_string(attr: &ast::Attribute) -> String {
 326     to_string(|s| s.print_attribute(attr))
 327 }
 328
 329 pub fn item_to_string(i: &ast::Item) -> String {
 330     to_string(|s| s.print_item(i))
 331 }
 332
 333 pub fn impl_item_to_string(i: &ast::ImplItem) -> String {
 334     to_string(|s| s.print_impl_item(i))
 335 }
 336
 337 pub fn trait_item_to_string(i: &ast::TraitItem) -> String {
 338     to_string(|s| s.print_trait_item(i))
 339 }
 340
 341 pub fn generic_params_to_string(generic_params: &[ast::GenericParam]) -> String {
 342     to_string(|s| s.print_generic_params(generic_params))
 343 }
 344
 345 pub fn where_clause_to_string(i: &ast::WhereClause) -> String {
 346     to_string(|s| s.print_where_clause(i))
 347 }
 348
 349 pub fn fn_block_to_string(p: &ast::FnDecl) -> String {
 350     to_string(|s| s.print_fn_block_args(p))
 351 }
 352
 353 pub fn path_to_string(p: &ast::Path) -> String {
 354     to_string(|s| s.print_path(p, false, 0))
 355 }
 356
 357 pub fn path_segment_to_string(p: &ast::PathSegment) -> String {
 358     to_string(|s| s.print_path_segment(p, false))
 359 }
 360
 361 pub fn ident_to_string(id: ast::Ident) -> String {
 362     to_string(|s| s.print_ident(id))
 363 }
 364
 365 pub fn vis_to_string(v: &ast::Visibility) -> String {
 366     to_string(|s| s.print_visibility(v))
 367 }
 368
 369 pub fn fun_to_string(decl: &ast::FnDecl,
 370                      header: ast::FnHeader,
 371                      name: ast::Ident,
 372                      generics: &ast::Generics)
 373                      -> String {
 374     to_string(|s| {
 375         s.head("")?;
 376         s.print_fn(decl, header, Some(name),
 377                    generics, &source_map::dummy_spanned(ast::VisibilityKind::Inherited))?;
 378         s.end()?; // Close the head box
 379         s.end() // Close the outer box
 380     })
 381 }
 382
 383 pub fn block_to_string(blk: &ast::Block) -> String {
 384     to_string(|s| {
 385         // containing cbox, will be closed by print-block at }
 386         s.cbox(INDENT_UNIT)?;
 387         // head-ibox, will be closed by print-block after {
 388         s.ibox(0)?;
 389         s.print_block(blk)
 390     })
 391 }
 392
 393 pub fn meta_list_item_to_string(li: &ast::NestedMetaItem) -> String {
 394     to_string(|s| s.print_meta_list_item(li))
 395 }
 396
 397 pub fn meta_item_to_string(mi: &ast::MetaItem) -> String {
 398     to_string(|s| s.print_meta_item(mi))
 399 }
 400
 401 pub fn attribute_to_string(attr: &ast::Attribute) -> String {
 402     to_string(|s| s.print_attribute(attr))
 403 }
 404
 405 pub fn lit_to_string(l: &ast::Lit) -> String {
 406     to_string(|s| s.print_literal(l))
 407 }
 408
 409 pub fn variant_to_string(var: &ast::Variant) -> String {
 410     to_string(|s| s.print_variant(var))
 411 }
 412
 413 pub fn arg_to_string(arg: &ast::Arg) -> String {
 414     to_string(|s| s.print_arg(arg, false))
 415 }
 416
 417 pub fn mac_to_string(arg: &ast::Mac) -> String {
 418     to_string(|s| s.print_mac(arg))
 419 }
 420
 421 pub fn foreign_item_to_string(arg: &ast::ForeignItem) -> String {
 422     to_string(|s| s.print_foreign_item(arg))
 423 }
 424
 425 pub fn visibility_qualified(vis: &ast::Visibility, s: &str) -> String {
 426     format!("{}{}", to_string(|s| s.print_visibility(vis)), s)
 427 }
 428
 429 pub trait PrintState<'a> {
 430     fn writer(&mut self) -> &mut pp::Printer<'a>;
 431     fn boxes(&mut self) -> &mut Vec<pp::Breaks>;
 432     fn comments(&mut self) -> &mut Option<Vec<comments::Comment>>;
 433     fn cur_cmnt(&mut self) -> &mut usize;
 434     fn cur_lit(&mut self) -> Option<&comments::Literal>;
 435     fn bump_lit(&mut self) -> Option<comments::Literal>;
 436
 437     fn word_space<S: Into<Cow<'static, str>>>(&mut self, w: S) -> io::Result<()> {
 438         self.writer().word(w)?;
 439         self.writer().space()
 440     }
 441
 442     fn popen(&mut self) -> io::Result<()> { self.writer().word("(") }
 443
 444     fn pclose(&mut self) -> io::Result<()> { self.writer().word(")") }
 445
 446     fn is_begin(&mut self) -> bool {
 447         match self.writer().last_token() {
 448             pp::Token::Begin(_) => true,
 449             _ => false,
 450         }
 451     }
 452
 453     fn is_end(&mut self) -> bool {
 454         match self.writer().last_token() {
 455             pp::Token::End => true,
 456             _ => false,
 457         }
 458     }
 459
 460     // is this the beginning of a line?
 461     fn is_bol(&mut self) -> bool {
 462         self.writer().last_token().is_eof() || self.writer().last_token().is_hardbreak_tok()
 463     }
 464
 465     fn hardbreak_if_not_bol(&mut self) -> io::Result<()> {
 466         if !self.is_bol() {
 467             self.writer().hardbreak()?
 468         }
 469         Ok(())
 470     }
 471
 472     // "raw box"
 473     fn rbox(&mut self, u: usize, b: pp::Breaks) -> io::Result<()> {
 474         self.boxes().push(b);
 475         self.writer().rbox(u, b)
 476     }
 477
 478     fn ibox(&mut self, u: usize) -> io::Result<()> {
 479         self.boxes().push(pp::Breaks::Inconsistent);
 480         self.writer().ibox(u)
 481     }
 482
 483     fn end(&mut self) -> io::Result<()> {
 484         self.boxes().pop().unwrap();
 485         self.writer().end()
 486     }
 487
 488     fn commasep<T, F>(&mut self, b: Breaks, elts: &[T], mut op: F) -> io::Result<()>
 489         where F: FnMut(&mut Self, &T) -> io::Result<()>,
 490     {
 491         self.rbox(0, b)?;
 492         let mut first = true;
 493         for elt in elts {
 494             if first { first = false; } else { self.word_space(",")?; }
 495             op(self, elt)?;
 496         }
 497         self.end()
 498     }
 499
 500     fn next_lit(&mut self, pos: BytePos) -> Option<comments::Literal> {
 501         while let Some(ltrl) = self.cur_lit().cloned() {
 502             if ltrl.pos > pos { break; }
 503
 504             // we don't need the value here since we're forced to clone cur_lit
 505             // due to lack of NLL.
 506             self.bump_lit();
 507             if ltrl.pos == pos {
 508                 return Some(ltrl);
 509             }
 510         }
 511
 512         None
 513     }
 514
 515     fn maybe_print_comment(&mut self, pos: BytePos) -> io::Result<()> {
 516         while let Some(ref cmnt) = self.next_comment() {
 517             if cmnt.pos < pos {
 518                 self.print_comment(cmnt)?;
 519             } else {
 520                 break
 521             }
 522         }
 523         Ok(())
 524     }
 525
 526     fn print_comment(&mut self,
 527                      cmnt: &comments::Comment) -> io::Result<()> {
 528         let r = match cmnt.style {
 529             comments::Mixed => {
 530                 assert_eq!(cmnt.lines.len(), 1);
 531                 self.writer().zerobreak()?;
 532                 self.writer().word(cmnt.lines[0].clone())?;
 533                 self.writer().zerobreak()
 534             }
 535             comments::Isolated => {
 536                 self.hardbreak_if_not_bol()?;
 537                 for line in &cmnt.lines {
 538                     // Don't print empty lines because they will end up as trailing
 539                     // whitespace
 540                     if !line.is_empty() {
 541                         self.writer().word(line.clone())?;
 542                     }
 543                     self.writer().hardbreak()?;
 544                 }
 545                 Ok(())
 546             }
 547             comments::Trailing => {
 548                 if !self.is_bol() {
 549                     self.writer().word(" ")?;
 550                 }
 551                 if cmnt.lines.len() == 1 {
 552                     self.writer().word(cmnt.lines[0].clone())?;
 553                     self.writer().hardbreak()
 554                 } else {
 555                     self.ibox(0)?;
 556                     for line in &cmnt.lines {
 557                         if !line.is_empty() {
 558                             self.writer().word(line.clone())?;
 559                         }
 560                         self.writer().hardbreak()?;
 561                     }
 562                     self.end()
 563                 }
 564             }
 565             comments::BlankLine => {
 566                 // We need to do at least one, possibly two hardbreaks.
 567                 let is_semi = match self.writer().last_token() {
 568                     pp::Token::String(s, _) => ";" == s,
 569                     _ => false
 570                 };
 571                 if is_semi || self.is_begin() || self.is_end() {
 572                     self.writer().hardbreak()?;
 573                 }
 574                 self.writer().hardbreak()
 575             }
 576         };
 577         match r {
 578             Ok(()) => {
 579                 *self.cur_cmnt() = *self.cur_cmnt() + 1;
 580                 Ok(())
 581             }
 582             Err(e) => Err(e),
 583         }
 584     }
 585
 586     fn next_comment(&mut self) -> Option<comments::Comment> {
 587         let cur_cmnt = *self.cur_cmnt();
 588         match *self.comments() {
 589             Some(ref cmnts) => {
 590                 if cur_cmnt < cmnts.len() {
 591                     Some(cmnts[cur_cmnt].clone())
 592                 } else {
 593                     None
 594                 }
 595             }
 596             _ => None
 597         }
 598     }
 599
 600     fn print_literal(&mut self, lit: &ast::Lit) -> io::Result<()> {
 601         self.maybe_print_comment(lit.span.lo())?;
 602         if let Some(ltrl) = self.next_lit(lit.span.lo()) {
 603             return self.writer().word(ltrl.lit.clone());
 604         }
 605         match lit.node {
 606             ast::LitKind::Str(st, style) => self.print_string(&st.as_str(), style),
 607             ast::LitKind::Byte(byte) => {
 608                 let mut res = String::from("b'");
 609                 res.extend(ascii::escape_default(byte).map(|c| c as char));
 610                 res.push('\'');
 611                 self.writer().word(res)
 612             }
 613             ast::LitKind::Char(ch) => {
 614                 let mut res = String::from("'");
 615                 res.extend(ch.escape_default());
 616                 res.push('\'');
 617                 self.writer().word(res)
 618             }
 619             ast::LitKind::Int(i, t) => {
 620                 match t {
 621                     ast::LitIntType::Signed(st) => {
 622                         self.writer().word(st.val_to_string(i as i128))
 623                     }
 624                     ast::LitIntType::Unsigned(ut) => {
 625                         self.writer().word(ut.val_to_string(i))
 626                     }
 627                     ast::LitIntType::Unsuffixed => {
 628                         self.writer().word(i.to_string())
 629                     }
 630                 }
 631             }
 632             ast::LitKind::Float(ref f, t) => {
 633                 self.writer().word(format!("{}{}", &f, t.ty_to_string()))
 634             }
 635             ast::LitKind::FloatUnsuffixed(ref f) => self.writer().word(f.as_str().get()),
 636             ast::LitKind::Bool(val) => {
 637                 if val { self.writer().word("true") } else { self.writer().word("false") }
 638             }
 639             ast::LitKind::ByteStr(ref v) => {
 640                 let mut escaped: String = String::new();
 641                 for &ch in v.iter() {
 642                     escaped.extend(ascii::escape_default(ch)
 643                                          .map(|c| c as char));
 644                 }
 645                 self.writer().word(format!("b\"{}\"", escaped))
 646             }
 647         }
 648     }
 649
 650     fn print_string(&mut self, st: &str,
 651                     style: ast::StrStyle) -> io::Result<()> {
 652         let st = match style {
 653             ast::StrStyle::Cooked => {
 654                 (format!("\"{}\"", st.escape_debug()))
 655             }
 656             ast::StrStyle::Raw(n) => {
 657                 (format!("r{delim}\"{string}\"{delim}",
 658                          delim="#".repeat(n as usize),
 659                          string=st))
 660             }
 661         };
 662         self.writer().word(st)
 663     }
 664
 665     fn print_inner_attributes(&mut self,
 666                               attrs: &[ast::Attribute]) -> io::Result<()> {
 667         self.print_either_attributes(attrs, ast::AttrStyle::Inner, false, true)
 668     }
 669
 670     fn print_inner_attributes_no_trailing_hardbreak(&mut self,
 671                                                    attrs: &[ast::Attribute])
 672                                                    -> io::Result<()> {
 673         self.print_either_attributes(attrs, ast::AttrStyle::Inner, false, false)
 674     }
 675
 676     fn print_outer_attributes(&mut self,
 677                               attrs: &[ast::Attribute]) -> io::Result<()> {
 678         self.print_either_attributes(attrs, ast::AttrStyle::Outer, false, true)
 679     }
 680
 681     fn print_inner_attributes_inline(&mut self,
 682                                      attrs: &[ast::Attribute]) -> io::Result<()> {
 683         self.print_either_attributes(attrs, ast::AttrStyle::Inner, true, true)
 684     }
 685
 686     fn print_outer_attributes_inline(&mut self,
 687                                      attrs: &[ast::Attribute]) -> io::Result<()> {
 688         self.print_either_attributes(attrs, ast::AttrStyle::Outer, true, true)
 689     }
 690
 691     fn print_either_attributes(&mut self,
 692                               attrs: &[ast::Attribute],
 693                               kind: ast::AttrStyle,
 694                               is_inline: bool,
 695                               trailing_hardbreak: bool) -> io::Result<()> {
 696         let mut count = 0;
 697         for attr in attrs {
 698             if attr.style == kind {
 699                 self.print_attribute_inline(attr, is_inline)?;
 700                 if is_inline {
 701                     self.nbsp()?;
 702                 }
 703                 count += 1;
 704             }
 705         }
 706         if count > 0 && trailing_hardbreak && !is_inline {
 707             self.hardbreak_if_not_bol()?;
 708         }
 709         Ok(())
 710     }
 711
 712     fn print_attribute_path(&mut self, path: &ast::Path) -> io::Result<()> {
 713         for (i, segment) in path.segments.iter().enumerate() {
 714             if i > 0 {
 715                 self.writer().word("::")?
 716             }
 717             if segment.ident.name != keywords::PathRoot.name() {
 718                 if segment.ident.name == keywords::DollarCrate.name() {
 719                     self.print_dollar_crate(segment.ident)?;
 720                 } else {
 721                     self.writer().word(segment.ident.as_str().get())?;
 722                 }
 723             }
 724         }
 725         Ok(())
 726     }
 727
 728     fn print_attribute(&mut self, attr: &ast::Attribute) -> io::Result<()> {
 729         self.print_attribute_inline(attr, false)
 730     }
 731
 732     fn print_attribute_inline(&mut self, attr: &ast::Attribute,
 733                               is_inline: bool) -> io::Result<()> {
 734         if !is_inline {
 735             self.hardbreak_if_not_bol()?;
 736         }
 737         self.maybe_print_comment(attr.span.lo())?;
 738         if attr.is_sugared_doc {
 739             self.writer().word(attr.value_str().unwrap().as_str().get())?;
 740             self.writer().hardbreak()
 741         } else {
 742             match attr.style {
 743                 ast::AttrStyle::Inner => self.writer().word("#![")?,
 744                 ast::AttrStyle::Outer => self.writer().word("#[")?,
 745             }
 746             if let Some(mi) = attr.meta() {
 747                 self.print_meta_item(&mi)?
 748             } else {
 749                 self.print_attribute_path(&attr.path)?;
 750                 self.writer().space()?;
 751                 self.print_tts(attr.tokens.clone())?;
 752             }
 753             self.writer().word("]")
 754         }
 755     }
 756
 757     fn print_meta_list_item(&mut self, item: &ast::NestedMetaItem) -> io::Result<()> {
 758         match item.node {
 759             ast::NestedMetaItemKind::MetaItem(ref mi) => {
 760                 self.print_meta_item(mi)
 761             },
 762             ast::NestedMetaItemKind::Literal(ref lit) => {
 763                 self.print_literal(lit)
 764             }
 765         }
 766     }
 767
 768     fn print_meta_item(&mut self, item: &ast::MetaItem) -> io::Result<()> {
 769         self.ibox(INDENT_UNIT)?;
 770         match item.node {
 771             ast::MetaItemKind::Word => self.print_attribute_path(&item.ident)?,
 772             ast::MetaItemKind::NameValue(ref value) => {
 773                 self.print_attribute_path(&item.ident)?;
 774                 self.writer().space()?;
 775                 self.word_space("=")?;
 776                 self.print_literal(value)?;
 777             }
 778             ast::MetaItemKind::List(ref items) => {
 779                 self.print_attribute_path(&item.ident)?;
 780                 self.popen()?;
 781                 self.commasep(Consistent,
 782                               &items[..],
 783                               |s, i| s.print_meta_list_item(i))?;
 784                 self.pclose()?;
 785             }
 786         }
 787         self.end()
 788     }
 789
 790     /// This doesn't deserve to be called "pretty" printing, but it should be
 791     /// meaning-preserving. A quick hack that might help would be to look at the
 792     /// spans embedded in the TTs to decide where to put spaces and newlines.
 793     /// But it'd be better to parse these according to the grammar of the
 794     /// appropriate macro, transcribe back into the grammar we just parsed from,
 795     /// and then pretty-print the resulting AST nodes (so, e.g., we print
 796     /// expression arguments as expressions). It can be done! I think.
 797     fn print_tt(&mut self, tt: tokenstream::TokenTree) -> io::Result<()> {
 798         match tt {
 799             TokenTree::Token(_, ref tk) => {
 800                 self.writer().word(token_to_string(tk))?;
 801                 match *tk {
 802                     parse::token::DocComment(..) => {
 803                         self.writer().hardbreak()
 804                     }
 805                     _ => Ok(())
 806                 }
 807             }
 808             TokenTree::Delimited(_, delim, tts) => {
 809                 self.writer().word(token_to_string(&token::OpenDelim(delim)))?;
 810                 self.writer().space()?;
 811                 self.print_tts(tts.stream())?;
 812                 self.writer().space()?;
 813                 self.writer().word(token_to_string(&token::CloseDelim(delim)))
 814             },
 815         }
 816     }
 817
 818     fn print_tts(&mut self, tts: tokenstream::TokenStream) -> io::Result<()> {
 819         self.ibox(0)?;
 820         for (i, tt) in tts.into_trees().enumerate() {
 821             if i != 0 {
 822                 self.writer().space()?;
 823             }
 824             self.print_tt(tt)?;
 825         }
 826         self.end()
 827     }
 828
 829     fn space_if_not_bol(&mut self) -> io::Result<()> {
 830         if !self.is_bol() { self.writer().space()?; }
 831         Ok(())
 832     }
 833
 834     fn nbsp(&mut self) -> io::Result<()> { self.writer().word(" ") }
 835
 836     // AST pretty-printer is used as a fallback for turning AST structures into token streams for
 837     // proc macros. Additionally, proc macros may stringify their input and expect it survive the
 838     // stringification (especially true for proc macro derives written between Rust 1.15 and 1.30).
 839     // So we need to somehow pretty-print `$crate` in paths in a way preserving at least some of
 840     // its hygiene data, most importantly name of the crate it refers to.
 841     // As a result we print `$crate` as `crate` if it refers to the local crate
 842     // and as `::other_crate_name` if it refers to some other crate.
 843     fn print_dollar_crate(&mut self, ident: ast::Ident) -> io::Result<()> {
 844         let name = ident.span.ctxt().dollar_crate_name();
 845         if !ast::Ident::with_empty_ctxt(name).is_path_segment_keyword() {
 846             self.writer().word("::")?;
 847         }
 848         self.writer().word(name.as_str().get())
 849     }
 850 }
 851
 852 impl<'a> PrintState<'a> for State<'a> {
 853     fn writer(&mut self) -> &mut pp::Printer<'a> {
 854         &mut self.s
 855     }
 856
 857     fn boxes(&mut self) -> &mut Vec<pp::Breaks> {
 858         &mut self.boxes
 859     }
 860
 861     fn comments(&mut self) -> &mut Option<Vec<comments::Comment>> {
 862         &mut self.comments
 863     }
 864
 865     fn cur_cmnt(&mut self) -> &mut usize {
 866         &mut self.cur_cmnt
 867     }
 868
 869     fn cur_lit(&mut self) -> Option<&comments::Literal> {
 870         self.literals.peek()
 871     }
 872
 873     fn bump_lit(&mut self) -> Option<comments::Literal> {
 874         self.literals.next()
 875     }
 876 }
 877
 878 impl<'a> State<'a> {
 879     pub fn cbox(&mut self, u: usize) -> io::Result<()> {
 880         self.boxes.push(pp::Breaks::Consistent);
 881         self.s.cbox(u)
 882     }
 883
 884     pub fn word_nbsp<S: Into<Cow<'static, str>>>(&mut self, w: S) -> io::Result<()> {
 885         self.s.word(w)?;
 886         self.nbsp()
 887     }
 888
 889     pub fn head<S: Into<Cow<'static, str>>>(&mut self, w: S) -> io::Result<()> {
 890         let w = w.into();
 891         // outer-box is consistent
 892         self.cbox(INDENT_UNIT)?;
 893         // head-box is inconsistent
 894         self.ibox(w.len() + 1)?;
 895         // keyword that starts the head
 896         if !w.is_empty() {
 897             self.word_nbsp(w)?;
 898         }
 899         Ok(())
 900     }
 901
 902     pub fn bopen(&mut self) -> io::Result<()> {
 903         self.s.word("{")?;
 904         self.end() // close the head-box
 905     }
 906
 907     pub fn bclose_(&mut self, span: syntax_pos::Span,
 908                    indented: usize) -> io::Result<()> {
 909         self.bclose_maybe_open(span, indented, true)
 910     }
 911     pub fn bclose_maybe_open(&mut self, span: syntax_pos::Span,
 912                              indented: usize, close_box: bool) -> io::Result<()> {
 913         self.maybe_print_comment(span.hi())?;
 914         self.break_offset_if_not_bol(1, -(indented as isize))?;
 915         self.s.word("}")?;
 916         if close_box {
 917             self.end()?; // close the outer-box
 918         }
 919         Ok(())
 920     }
 921     pub fn bclose(&mut self, span: syntax_pos::Span) -> io::Result<()> {
 922         self.bclose_(span, INDENT_UNIT)
 923     }
 924
 925     pub fn in_cbox(&self) -> bool {
 926         match self.boxes.last() {
 927             Some(&last_box) => last_box == pp::Breaks::Consistent,
 928             None => false
 929         }
 930     }
 931
 932     pub fn break_offset_if_not_bol(&mut self, n: usize,
 933                                    off: isize) -> io::Result<()> {
 934         if !self.is_bol() {
 935             self.s.break_offset(n, off)
 936         } else {
 937             if off != 0 && self.s.last_token().is_hardbreak_tok() {
 938                 // We do something pretty sketchy here: tuck the nonzero
 939                 // offset-adjustment we were going to deposit along with the
 940                 // break into the previous hardbreak.
 941                 self.s.replace_last_token(pp::Printer::hardbreak_tok_offset(off));
 942             }
 943             Ok(())
 944         }
 945     }
 946
 947     // Synthesizes a comment that was not textually present in the original source
 948     // file.
 949     pub fn synth_comment(&mut self, text: String) -> io::Result<()> {
 950         self.s.word("/*")?;
 951         self.s.space()?;
 952         self.s.word(text)?;
 953         self.s.space()?;
 954         self.s.word("*/")
 955     }
 956
 957
 958
 959     pub fn commasep_cmnt<T, F, G>(&mut self,
 960                                   b: Breaks,
 961                                   elts: &[T],
 962                                   mut op: F,
 963                                   mut get_span: G) -> io::Result<()> where
 964         F: FnMut(&mut State, &T) -> io::Result<()>,
 965         G: FnMut(&T) -> syntax_pos::Span,
 966     {
 967         self.rbox(0, b)?;
 968         let len = elts.len();
 969         let mut i = 0;
 970         for elt in elts {
 971             self.maybe_print_comment(get_span(elt).hi())?;
 972             op(self, elt)?;
 973             i += 1;
 974             if i < len {
 975                 self.s.word(",")?;
 976                 self.maybe_print_trailing_comment(get_span(elt),
 977                                                   Some(get_span(&elts[i]).hi()))?;
 978                 self.space_if_not_bol()?;
 979             }
 980         }
 981         self.end()
 982     }
 983
 984     pub fn commasep_exprs(&mut self, b: Breaks,
 985                           exprs: &[P<ast::Expr>]) -> io::Result<()> {
 986         self.commasep_cmnt(b, exprs, |s, e| s.print_expr(e), |e| e.span)
 987     }
 988
 989     pub fn print_mod(&mut self, _mod: &ast::Mod,
 990                      attrs: &[ast::Attribute]) -> io::Result<()> {
 991         self.print_inner_attributes(attrs)?;
 992         for item in &_mod.items {
 993             self.print_item(item)?;
 994         }
 995         Ok(())
 996     }
 997
 998     pub fn print_foreign_mod(&mut self, nmod: &ast::ForeignMod,
 999                              attrs: &[ast::Attribute]) -> io::Result<()> {
1000         self.print_inner_attributes(attrs)?;
1001         for item in &nmod.items {
1002             self.print_foreign_item(item)?;
1003         }
1004         Ok(())
1005     }
1006
1007     pub fn print_opt_lifetime(&mut self, lifetime: &Option<ast::Lifetime>) -> io::Result<()> {
1008         if let Some(lt) = *lifetime {
1009             self.print_lifetime(lt)?;
1010             self.nbsp()?;
1011         }
1012         Ok(())
1013     }
1014
1015     pub fn print_generic_arg(&mut self, generic_arg: &GenericArg) -> io::Result<()> {
1016         match generic_arg {
1017             GenericArg::Lifetime(lt) => self.print_lifetime(*lt),
1018             GenericArg::Type(ty) => self.print_type(ty),
1019         }
1020     }
1021
1022     pub fn print_type(&mut self, ty: &ast::Ty) -> io::Result<()> {
1023         self.maybe_print_comment(ty.span.lo())?;
1024         self.ibox(0)?;
1025         match ty.node {
1026             ast::TyKind::Slice(ref ty) => {
1027                 self.s.word("[")?;
1028                 self.print_type(ty)?;
1029                 self.s.word("]")?;
1030             }
1031             ast::TyKind::Ptr(ref mt) => {
1032                 self.s.word("*")?;
1033                 match mt.mutbl {
1034                     ast::Mutability::Mutable => self.word_nbsp("mut")?,
1035                     ast::Mutability::Immutable => self.word_nbsp("const")?,
1036                 }
1037                 self.print_type(&mt.ty)?;
1038             }
1039             ast::TyKind::Rptr(ref lifetime, ref mt) => {
1040                 self.s.word("&")?;
1041                 self.print_opt_lifetime(lifetime)?;
1042                 self.print_mt(mt)?;
1043             }
1044             ast::TyKind::Never => {
1045                 self.s.word("!")?;
1046             },
1047             ast::TyKind::Tup(ref elts) => {
1048                 self.popen()?;
1049                 self.commasep(Inconsistent, &elts[..],
1050                               |s, ty| s.print_type(ty))?;
1051                 if elts.len() == 1 {
1052                     self.s.word(",")?;
1053                 }
1054                 self.pclose()?;
1055             }
1056             ast::TyKind::Paren(ref typ) => {
1057                 self.popen()?;
1058                 self.print_type(typ)?;
1059                 self.pclose()?;
1060             }
1061             ast::TyKind::BareFn(ref f) => {
1062                 self.print_ty_fn(f.abi,
1063                                  f.unsafety,
1064                                  &f.decl,
1065                                  None,
1066                                  &f.generic_params)?;
1067             }
1068             ast::TyKind::Path(None, ref path) => {
1069                 self.print_path(path, false, 0)?;
1070             }
1071             ast::TyKind::Path(Some(ref qself), ref path) => {
1072                 self.print_qpath(path, qself, false)?
1073             }
1074             ast::TyKind::TraitObject(ref bounds, syntax) => {
1075                 let prefix = if syntax == ast::TraitObjectSyntax::Dyn { "dyn" } else { "" };
1076                 self.print_type_bounds(prefix, &bounds[..])?;
1077             }
1078             ast::TyKind::ImplTrait(_, ref bounds) => {
1079                 self.print_type_bounds("impl", &bounds[..])?;
1080             }
1081             ast::TyKind::Array(ref ty, ref length) => {
1082                 self.s.word("[")?;
1083                 self.print_type(ty)?;
1084                 self.s.word("; ")?;
1085                 self.print_expr(&length.value)?;
1086                 self.s.word("]")?;
1087             }
1088             ast::TyKind::Typeof(ref e) => {
1089                 self.s.word("typeof(")?;
1090                 self.print_expr(&e.value)?;
1091                 self.s.word(")")?;
1092             }
1093             ast::TyKind::Infer => {
1094                 self.s.word("_")?;
1095             }
1096             ast::TyKind::Err => {
1097                 self.popen()?;
1098                 self.s.word("/*ERROR*/")?;
1099                 self.pclose()?;
1100             }
1101             ast::TyKind::ImplicitSelf => {
1102                 self.s.word("Self")?;
1103             }
1104             ast::TyKind::Mac(ref m) => {
1105                 self.print_mac(m)?;
1106             }
1107         }
1108         self.end()
1109     }
1110
1111     pub fn print_foreign_item(&mut self,
1112                               item: &ast::ForeignItem) -> io::Result<()> {
1113         self.hardbreak_if_not_bol()?;
1114         self.maybe_print_comment(item.span.lo())?;
1115         self.print_outer_attributes(&item.attrs)?;
1116         match item.node {
1117             ast::ForeignItemKind::Fn(ref decl, ref generics) => {
1118                 self.head("")?;
1119                 self.print_fn(decl, ast::FnHeader::default(),
1120                               Some(item.ident),
1121                               generics, &item.vis)?;
1122                 self.end()?; // end head-ibox
1123                 self.s.word(";")?;
1124                 self.end() // end the outer fn box
1125             }
1126             ast::ForeignItemKind::Static(ref t, m) => {
1127                 self.head(visibility_qualified(&item.vis, "static"))?;
1128                 if m {
1129                     self.word_space("mut")?;
1130                 }
1131                 self.print_ident(item.ident)?;
1132                 self.word_space(":")?;
1133                 self.print_type(t)?;
1134                 self.s.word(";")?;
1135                 self.end()?; // end the head-ibox
1136                 self.end() // end the outer cbox
1137             }
1138             ast::ForeignItemKind::Ty => {
1139                 self.head(visibility_qualified(&item.vis, "type"))?;
1140                 self.print_ident(item.ident)?;
1141                 self.s.word(";")?;
1142                 self.end()?; // end the head-ibox
1143                 self.end() // end the outer cbox
1144             }
1145             ast::ForeignItemKind::Macro(ref m) => {
1146                 self.print_mac(m)?;
1147                 match m.node.delim {
1148                     MacDelimiter::Brace => Ok(()),
1149                     _ => self.s.word(";")
1150                 }
1151             }
1152         }
1153     }
1154
1155     fn print_associated_const(&mut self,
1156                               ident: ast::Ident,
1157                               ty: &ast::Ty,
1158                               default: Option<&ast::Expr>,
1159                               vis: &ast::Visibility)
1160                               -> io::Result<()>
1161     {
1162         self.s.word(visibility_qualified(vis, ""))?;
1163         self.word_space("const")?;
1164         self.print_ident(ident)?;
1165         self.word_space(":")?;
1166         self.print_type(ty)?;
1167         if let Some(expr) = default {
1168             self.s.space()?;
1169             self.word_space("=")?;
1170             self.print_expr(expr)?;
1171         }
1172         self.s.word(";")
1173     }
1174
1175     fn print_associated_type(&mut self,
1176                              ident: ast::Ident,
1177                              bounds: Option<&ast::GenericBounds>,
1178                              ty: Option<&ast::Ty>)
1179                              -> io::Result<()> {
1180         self.word_space("type")?;
1181         self.print_ident(ident)?;
1182         if let Some(bounds) = bounds {
1183             self.print_type_bounds(":", bounds)?;
1184         }
1185         if let Some(ty) = ty {
1186             self.s.space()?;
1187             self.word_space("=")?;
1188             self.print_type(ty)?;
1189         }
1190         self.s.word(";")
1191     }
1192
1193     /// Pretty-print an item
1194     pub fn print_item(&mut self, item: &ast::Item) -> io::Result<()> {
1195         self.hardbreak_if_not_bol()?;
1196         self.maybe_print_comment(item.span.lo())?;
1197         self.print_outer_attributes(&item.attrs)?;
1198         self.ann.pre(self, AnnNode::Item(item))?;
1199         match item.node {
1200             ast::ItemKind::ExternCrate(orig_name) => {
1201                 self.head(visibility_qualified(&item.vis, "extern crate"))?;
1202                 if let Some(orig_name) = orig_name {
1203                     self.print_name(orig_name)?;
1204                     self.s.space()?;
1205                     self.s.word("as")?;
1206                     self.s.space()?;
1207                 }
1208                 self.print_ident(item.ident)?;
1209                 self.s.word(";")?;
1210                 self.end()?; // end inner head-block
1211                 self.end()?; // end outer head-block
1212             }
1213             ast::ItemKind::Use(ref tree) => {
1214                 self.head(visibility_qualified(&item.vis, "use"))?;
1215                 self.print_use_tree(tree)?;
1216                 self.s.word(";")?;
1217                 self.end()?; // end inner head-block
1218                 self.end()?; // end outer head-block
1219             }
1220             ast::ItemKind::Static(ref ty, m, ref expr) => {
1221                 self.head(visibility_qualified(&item.vis, "static"))?;
1222                 if m == ast::Mutability::Mutable {
1223                     self.word_space("mut")?;
1224                 }
1225                 self.print_ident(item.ident)?;
1226                 self.word_space(":")?;
1227                 self.print_type(ty)?;
1228                 self.s.space()?;
1229                 self.end()?; // end the head-ibox
1230
1231                 self.word_space("=")?;
1232                 self.print_expr(expr)?;
1233                 self.s.word(";")?;
1234                 self.end()?; // end the outer cbox
1235             }
1236             ast::ItemKind::Const(ref ty, ref expr) => {
1237                 self.head(visibility_qualified(&item.vis, "const"))?;
1238                 self.print_ident(item.ident)?;
1239                 self.word_space(":")?;
1240                 self.print_type(ty)?;
1241                 self.s.space()?;
1242                 self.end()?; // end the head-ibox
1243
1244                 self.word_space("=")?;
1245                 self.print_expr(expr)?;
1246                 self.s.word(";")?;
1247                 self.end()?; // end the outer cbox
1248             }
1249             ast::ItemKind::Fn(ref decl, header, ref typarams, ref body) => {
1250                 self.head("")?;
1251                 self.print_fn(
1252                     decl,
1253                     header,
1254                     Some(item.ident),
1255                     typarams,
1256                     &item.vis
1257                 )?;
1258                 self.s.word(" ")?;
1259                 self.print_block_with_attrs(body, &item.attrs)?;
1260             }
1261             ast::ItemKind::Mod(ref _mod) => {
1262                 self.head(visibility_qualified(&item.vis, "mod"))?;
1263                 self.print_ident(item.ident)?;
1264
1265                 if _mod.inline || self.is_expanded {
1266                     self.nbsp()?;
1267                     self.bopen()?;
1268                     self.print_mod(_mod, &item.attrs)?;
1269                     self.bclose(item.span)?;
1270                 } else {
1271                     self.s.word(";")?;
1272                     self.end()?; // end inner head-block
1273                     self.end()?; // end outer head-block
1274                 }
1275
1276             }
1277             ast::ItemKind::ForeignMod(ref nmod) => {
1278                 self.head("extern")?;
1279                 self.word_nbsp(nmod.abi.to_string())?;
1280                 self.bopen()?;
1281                 self.print_foreign_mod(nmod, &item.attrs)?;
1282                 self.bclose(item.span)?;
1283             }
1284             ast::ItemKind::GlobalAsm(ref ga) => {
1285                 self.head(visibility_qualified(&item.vis, "global_asm!"))?;
1286                 self.s.word(ga.asm.as_str().get())?;
1287                 self.end()?;
1288             }
1289             ast::ItemKind::Ty(ref ty, ref generics) => {
1290                 self.head(visibility_qualified(&item.vis, "type"))?;
1291                 self.print_ident(item.ident)?;
1292                 self.print_generic_params(&generics.params)?;
1293                 self.end()?; // end the inner ibox
1294
1295                 self.print_where_clause(&generics.where_clause)?;
1296                 self.s.space()?;
1297                 self.word_space("=")?;
1298                 self.print_type(ty)?;
1299                 self.s.word(";")?;
1300                 self.end()?; // end the outer ibox
1301             }
1302             ast::ItemKind::Existential(ref bounds, ref generics) => {
1303                 self.head(visibility_qualified(&item.vis, "existential type"))?;
1304                 self.print_ident(item.ident)?;
1305                 self.print_generic_params(&generics.params)?;
1306                 self.end()?; // end the inner ibox
1307
1308                 self.print_where_clause(&generics.where_clause)?;
1309                 self.s.space()?;
1310                 self.print_type_bounds(":", bounds)?;
1311                 self.s.word(";")?;
1312                 self.end()?; // end the outer ibox
1313             }
1314             ast::ItemKind::Enum(ref enum_definition, ref params) => {
1315                 self.print_enum_def(
1316                     enum_definition,
1317                     params,
1318                     item.ident,
1319                     item.span,
1320                     &item.vis
1321                 )?;
1322             }
1323             ast::ItemKind::Struct(ref struct_def, ref generics) => {
1324                 self.head(visibility_qualified(&item.vis, "struct"))?;
1325                 self.print_struct(struct_def, generics, item.ident, item.span, true)?;
1326             }
1327             ast::ItemKind::Union(ref struct_def, ref generics) => {
1328                 self.head(visibility_qualified(&item.vis, "union"))?;
1329                 self.print_struct(struct_def, generics, item.ident, item.span, true)?;
1330             }
1331             ast::ItemKind::Impl(unsafety,
1332                           polarity,
1333                           defaultness,
1334                           ref generics,
1335                           ref opt_trait,
1336                           ref ty,
1337                           ref impl_items) => {
1338                 self.head("")?;
1339                 self.print_visibility(&item.vis)?;
1340                 self.print_defaultness(defaultness)?;
1341                 self.print_unsafety(unsafety)?;
1342                 self.word_nbsp("impl")?;
1343
1344                 if !generics.params.is_empty() {
1345                     self.print_generic_params(&generics.params)?;
1346                     self.s.space()?;
1347                 }
1348
1349                 if polarity == ast::ImplPolarity::Negative {
1350                     self.s.word("!")?;
1351                 }
1352
1353                 if let Some(ref t) = *opt_trait {
1354                     self.print_trait_ref(t)?;
1355                     self.s.space()?;
1356                     self.word_space("for")?;
1357                 }
1358
1359                 self.print_type(ty)?;
1360                 self.print_where_clause(&generics.where_clause)?;
1361
1362                 self.s.space()?;
1363                 self.bopen()?;
1364                 self.print_inner_attributes(&item.attrs)?;
1365                 for impl_item in impl_items {
1366                     self.print_impl_item(impl_item)?;
1367                 }
1368                 self.bclose(item.span)?;
1369             }
1370             ast::ItemKind::Trait(is_auto, unsafety, ref generics, ref bounds, ref trait_items) => {
1371                 self.head("")?;
1372                 self.print_visibility(&item.vis)?;
1373                 self.print_unsafety(unsafety)?;
1374                 self.print_is_auto(is_auto)?;
1375                 self.word_nbsp("trait")?;
1376                 self.print_ident(item.ident)?;
1377                 self.print_generic_params(&generics.params)?;
1378                 let mut real_bounds = Vec::with_capacity(bounds.len());
1379                 for b in bounds.iter() {
1380                     if let GenericBound::Trait(ref ptr, ast::TraitBoundModifier::Maybe) = *b {
1381                         self.s.space()?;
1382                         self.word_space("for ?")?;
1383                         self.print_trait_ref(&ptr.trait_ref)?;
1384                     } else {
1385                         real_bounds.push(b.clone());
1386                     }
1387                 }
1388                 self.print_type_bounds(":", &real_bounds[..])?;
1389                 self.print_where_clause(&generics.where_clause)?;
1390                 self.s.word(" ")?;
1391                 self.bopen()?;
1392                 for trait_item in trait_items {
1393                     self.print_trait_item(trait_item)?;
1394                 }
1395                 self.bclose(item.span)?;
1396             }
1397             ast::ItemKind::TraitAlias(ref generics, ref bounds) => {
1398                 self.head("")?;
1399                 self.print_visibility(&item.vis)?;
1400                 self.word_nbsp("trait")?;
1401                 self.print_ident(item.ident)?;
1402                 self.print_generic_params(&generics.params)?;
1403                 let mut real_bounds = Vec::with_capacity(bounds.len());
1404                 // FIXME(durka) this seems to be some quite outdated syntax
1405                 for b in bounds.iter() {
1406                     if let GenericBound::Trait(ref ptr, ast::TraitBoundModifier::Maybe) = *b {
1407                         self.s.space()?;
1408                         self.word_space("for ?")?;
1409                         self.print_trait_ref(&ptr.trait_ref)?;
1410                     } else {
1411                         real_bounds.push(b.clone());
1412                     }
1413                 }
1414                 self.nbsp()?;
1415                 self.print_type_bounds("=", &real_bounds[..])?;
1416                 self.print_where_clause(&generics.where_clause)?;
1417                 self.s.word(";")?;
1418             }
1419             ast::ItemKind::Mac(ref mac) => {
1420                 if item.ident.name == keywords::Invalid.name() {
1421                     self.print_mac(mac)?;
1422                     match mac.node.delim {
1423                         MacDelimiter::Brace => {}
1424                         _ => self.s.word(";")?,
1425                     }
1426                 } else {
1427                     self.print_path(&mac.node.path, false, 0)?;
1428                     self.s.word("! ")?;
1429                     self.print_ident(item.ident)?;
1430                     self.cbox(INDENT_UNIT)?;
1431                     self.popen()?;
1432                     self.print_tts(mac.node.stream())?;
1433                     self.pclose()?;
1434                     self.s.word(";")?;
1435                     self.end()?;
1436                 }
1437             }
1438             ast::ItemKind::MacroDef(ref tts) => {
1439                 self.s.word("macro_rules! ")?;
1440                 self.print_ident(item.ident)?;
1441                 self.cbox(INDENT_UNIT)?;
1442                 self.popen()?;
1443                 self.print_tts(tts.stream())?;
1444                 self.pclose()?;
1445                 self.s.word(";")?;
1446                 self.end()?;
1447             }
1448         }
1449         self.ann.post(self, AnnNode::Item(item))
1450     }
1451
1452     fn print_trait_ref(&mut self, t: &ast::TraitRef) -> io::Result<()> {
1453         self.print_path(&t.path, false, 0)
1454     }
1455
1456     fn print_formal_generic_params(
1457         &mut self,
1458         generic_params: &[ast::GenericParam]
1459     ) -> io::Result<()> {
1460         if !generic_params.is_empty() {
1461             self.s.word("for")?;
1462             self.print_generic_params(generic_params)?;
1463             self.nbsp()?;
1464         }
1465         Ok(())
1466     }
1467
1468     fn print_poly_trait_ref(&mut self, t: &ast::PolyTraitRef) -> io::Result<()> {
1469         self.print_formal_generic_params(&t.bound_generic_params)?;
1470         self.print_trait_ref(&t.trait_ref)
1471     }
1472
1473     pub fn print_enum_def(&mut self, enum_definition: &ast::EnumDef,
1474                           generics: &ast::Generics, ident: ast::Ident,
1475                           span: syntax_pos::Span,
1476                           visibility: &ast::Visibility) -> io::Result<()> {
1477         self.head(visibility_qualified(visibility, "enum"))?;
1478         self.print_ident(ident)?;
1479         self.print_generic_params(&generics.params)?;
1480         self.print_where_clause(&generics.where_clause)?;
1481         self.s.space()?;
1482         self.print_variants(&enum_definition.variants, span)
1483     }
1484
1485     pub fn print_variants(&mut self,
1486                           variants: &[ast::Variant],
1487                           span: syntax_pos::Span) -> io::Result<()> {
1488         self.bopen()?;
1489         for v in variants {
1490             self.space_if_not_bol()?;
1491             self.maybe_print_comment(v.span.lo())?;
1492             self.print_outer_attributes(&v.node.attrs)?;
1493             self.ibox(INDENT_UNIT)?;
1494             self.print_variant(v)?;
1495             self.s.word(",")?;
1496             self.end()?;
1497             self.maybe_print_trailing_comment(v.span, None)?;
1498         }
1499         self.bclose(span)
1500     }
1501
1502     pub fn print_visibility(&mut self, vis: &ast::Visibility) -> io::Result<()> {
1503         match vis.node {
1504             ast::VisibilityKind::Public => self.word_nbsp("pub"),
1505             ast::VisibilityKind::Crate(sugar) => match sugar {
1506                 ast::CrateSugar::PubCrate => self.word_nbsp("pub(crate)"),
1507                 ast::CrateSugar::JustCrate => self.word_nbsp("crate")
1508             }
1509             ast::VisibilityKind::Restricted { ref path, .. } => {
1510                 let path = to_string(|s| s.print_path(path, false, 0));
1511                 if path == "self" || path == "super" {
1512                     self.word_nbsp(format!("pub({})", path))
1513                 } else {
1514                     self.word_nbsp(format!("pub(in {})", path))
1515                 }
1516             }
1517             ast::VisibilityKind::Inherited => Ok(())
1518         }
1519     }
1520
1521     pub fn print_defaultness(&mut self, defaultness: ast::Defaultness) -> io::Result<()> {
1522         if let ast::Defaultness::Default = defaultness {
1523             self.word_nbsp("default")?;
1524         }
1525         Ok(())
1526     }
1527
1528     pub fn print_struct(&mut self,
1529                         struct_def: &ast::VariantData,
1530                         generics: &ast::Generics,
1531                         ident: ast::Ident,
1532                         span: syntax_pos::Span,
1533                         print_finalizer: bool) -> io::Result<()> {
1534         self.print_ident(ident)?;
1535         self.print_generic_params(&generics.params)?;
1536         if !struct_def.is_struct() {
1537             if struct_def.is_tuple() {
1538                 self.popen()?;
1539                 self.commasep(
1540                     Inconsistent, struct_def.fields(),
1541                     |s, field| {
1542                         s.maybe_print_comment(field.span.lo())?;
1543                         s.print_outer_attributes(&field.attrs)?;
1544                         s.print_visibility(&field.vis)?;
1545                         s.print_type(&field.ty)
1546                     }
1547                 )?;
1548                 self.pclose()?;
1549             }
1550             self.print_where_clause(&generics.where_clause)?;
1551             if print_finalizer {
1552                 self.s.word(";")?;
1553             }
1554             self.end()?;
1555             self.end() // close the outer-box
1556         } else {
1557             self.print_where_clause(&generics.where_clause)?;
1558             self.nbsp()?;
1559             self.bopen()?;
1560             self.hardbreak_if_not_bol()?;
1561
1562             for field in struct_def.fields() {
1563                 self.hardbreak_if_not_bol()?;
1564                 self.maybe_print_comment(field.span.lo())?;
1565                 self.print_outer_attributes(&field.attrs)?;
1566                 self.print_visibility(&field.vis)?;
1567                 self.print_ident(field.ident.unwrap())?;
1568                 self.word_nbsp(":")?;
1569                 self.print_type(&field.ty)?;
1570                 self.s.word(",")?;
1571             }
1572
1573             self.bclose(span)
1574         }
1575     }
1576
1577     pub fn print_variant(&mut self, v: &ast::Variant) -> io::Result<()> {
1578         self.head("")?;
1579         let generics = ast::Generics::default();
1580         self.print_struct(&v.node.data, &generics, v.node.ident, v.span, false)?;
1581         match v.node.disr_expr {
1582             Some(ref d) => {
1583                 self.s.space()?;
1584                 self.word_space("=")?;
1585                 self.print_expr(&d.value)
1586             }
1587             _ => Ok(())
1588         }
1589     }
1590
1591     pub fn print_method_sig(&mut self,
1592                             ident: ast::Ident,
1593                             generics: &ast::Generics,
1594                             m: &ast::MethodSig,
1595                             vis: &ast::Visibility)
1596                             -> io::Result<()> {
1597         self.print_fn(&m.decl,
1598                       m.header,
1599                       Some(ident),
1600                       &generics,
1601                       vis)
1602     }
1603
1604     pub fn print_trait_item(&mut self, ti: &ast::TraitItem)
1605                             -> io::Result<()> {
1606         self.ann.pre(self, AnnNode::SubItem(ti.id))?;
1607         self.hardbreak_if_not_bol()?;
1608         self.maybe_print_comment(ti.span.lo())?;
1609         self.print_outer_attributes(&ti.attrs)?;
1610         match ti.node {
1611             ast::TraitItemKind::Const(ref ty, ref default) => {
1612                 self.print_associated_const(
1613                     ti.ident,
1614                     ty,
1615                     default.as_ref().map(|expr| &**expr),
1616                     &source_map::respan(ti.span.shrink_to_lo(), ast::VisibilityKind::Inherited),
1617                 )?;
1618             }
1619             ast::TraitItemKind::Method(ref sig, ref body) => {
1620                 if body.is_some() {
1621                     self.head("")?;
1622                 }
1623                 self.print_method_sig(
1624                     ti.ident,
1625                     &ti.generics,
1626                     sig,
1627                     &source_map::respan(ti.span.shrink_to_lo(), ast::VisibilityKind::Inherited),
1628                 )?;
1629                 if let Some(ref body) = *body {
1630                     self.nbsp()?;
1631                     self.print_block_with_attrs(body, &ti.attrs)?;
1632                 } else {
1633                     self.s.word(";")?;
1634                 }
1635             }
1636             ast::TraitItemKind::Type(ref bounds, ref default) => {
1637                 self.print_associated_type(ti.ident, Some(bounds),
1638                                            default.as_ref().map(|ty| &**ty))?;
1639             }
1640             ast::TraitItemKind::Macro(ref mac) => {
1641                 self.print_mac(mac)?;
1642                 match mac.node.delim {
1643                     MacDelimiter::Brace => {}
1644                     _ => self.s.word(";")?,
1645                 }
1646             }
1647         }
1648         self.ann.post(self, AnnNode::SubItem(ti.id))
1649     }
1650
1651     pub fn print_impl_item(&mut self, ii: &ast::ImplItem) -> io::Result<()> {
1652         self.ann.pre(self, AnnNode::SubItem(ii.id))?;
1653         self.hardbreak_if_not_bol()?;
1654         self.maybe_print_comment(ii.span.lo())?;
1655         self.print_outer_attributes(&ii.attrs)?;
1656         self.print_defaultness(ii.defaultness)?;
1657         match ii.node {
1658             ast::ImplItemKind::Const(ref ty, ref expr) => {
1659                 self.print_associated_const(ii.ident, ty, Some(expr), &ii.vis)?;
1660             }
1661             ast::ImplItemKind::Method(ref sig, ref body) => {
1662                 self.head("")?;
1663                 self.print_method_sig(ii.ident, &ii.generics, sig, &ii.vis)?;
1664                 self.nbsp()?;
1665                 self.print_block_with_attrs(body, &ii.attrs)?;
1666             }
1667             ast::ImplItemKind::Type(ref ty) => {
1668                 self.print_associated_type(ii.ident, None, Some(ty))?;
1669             }
1670             ast::ImplItemKind::Existential(ref bounds) => {
1671                 self.word_space("existential")?;
1672                 self.print_associated_type(ii.ident, Some(bounds), None)?;
1673             }
1674             ast::ImplItemKind::Macro(ref mac) => {
1675                 self.print_mac(mac)?;
1676                 match mac.node.delim {
1677                     MacDelimiter::Brace => {}
1678                     _ => self.s.word(";")?,
1679                 }
1680             }
1681         }
1682         self.ann.post(self, AnnNode::SubItem(ii.id))
1683     }
1684
1685     pub fn print_stmt(&mut self, st: &ast::Stmt) -> io::Result<()> {
1686         self.maybe_print_comment(st.span.lo())?;
1687         match st.node {
1688             ast::StmtKind::Local(ref loc) => {
1689                 self.print_outer_attributes(&loc.attrs)?;
1690                 self.space_if_not_bol()?;
1691                 self.ibox(INDENT_UNIT)?;
1692                 self.word_nbsp("let")?;
1693
1694                 self.ibox(INDENT_UNIT)?;
1695                 self.print_local_decl(loc)?;
1696                 self.end()?;
1697                 if let Some(ref init) = loc.init {
1698                     self.nbsp()?;
1699                     self.word_space("=")?;
1700                     self.print_expr(init)?;
1701                 }
1702                 self.s.word(";")?;
1703                 self.end()?;
1704             }
1705             ast::StmtKind::Item(ref item) => self.print_item(item)?,
1706             ast::StmtKind::Expr(ref expr) => {
1707                 self.space_if_not_bol()?;
1708                 self.print_expr_outer_attr_style(expr, false)?;
1709                 if parse::classify::expr_requires_semi_to_be_stmt(expr) {
1710                     self.s.word(";")?;
1711                 }
1712             }
1713             ast::StmtKind::Semi(ref expr) => {
1714                 self.space_if_not_bol()?;
1715                 self.print_expr_outer_attr_style(expr, false)?;
1716                 self.s.word(";")?;
1717             }
1718             ast::StmtKind::Mac(ref mac) => {
1719                 let (ref mac, style, ref attrs) = **mac;
1720                 self.space_if_not_bol()?;
1721                 self.print_outer_attributes(attrs)?;
1722                 self.print_mac(mac)?;
1723                 if style == ast::MacStmtStyle::Semicolon {
1724                     self.s.word(";")?;
1725                 }
1726             }
1727         }
1728         self.maybe_print_trailing_comment(st.span, None)
1729     }
1730
1731     pub fn print_block(&mut self, blk: &ast::Block) -> io::Result<()> {
1732         self.print_block_with_attrs(blk, &[])
1733     }
1734
1735     pub fn print_block_unclosed(&mut self, blk: &ast::Block) -> io::Result<()> {
1736         self.print_block_unclosed_indent(blk, INDENT_UNIT)
1737     }
1738
1739     pub fn print_block_unclosed_with_attrs(&mut self, blk: &ast::Block,
1740                                             attrs: &[ast::Attribute])
1741                                            -> io::Result<()> {
1742         self.print_block_maybe_unclosed(blk, INDENT_UNIT, attrs, false)
1743     }
1744
1745     pub fn print_block_unclosed_indent(&mut self, blk: &ast::Block,
1746                                        indented: usize) -> io::Result<()> {
1747         self.print_block_maybe_unclosed(blk, indented, &[], false)
1748     }
1749
1750     pub fn print_block_with_attrs(&mut self,
1751                                   blk: &ast::Block,
1752                                   attrs: &[ast::Attribute]) -> io::Result<()> {
1753         self.print_block_maybe_unclosed(blk, INDENT_UNIT, attrs, true)
1754     }
1755
1756     pub fn print_block_maybe_unclosed(&mut self,
1757                                       blk: &ast::Block,
1758                                       indented: usize,
1759                                       attrs: &[ast::Attribute],
1760                                       close_box: bool) -> io::Result<()> {
1761         match blk.rules {
1762             BlockCheckMode::Unsafe(..) => self.word_space("unsafe")?,
1763             BlockCheckMode::Default => ()
1764         }
1765         self.maybe_print_comment(blk.span.lo())?;
1766         self.ann.pre(self, AnnNode::Block(blk))?;
1767         self.bopen()?;
1768
1769         self.print_inner_attributes(attrs)?;
1770
1771         for (i, st) in blk.stmts.iter().enumerate() {
1772             match st.node {
1773                 ast::StmtKind::Expr(ref expr) if i == blk.stmts.len() - 1 => {
1774                     self.maybe_print_comment(st.span.lo())?;
1775                     self.space_if_not_bol()?;
1776                     self.print_expr_outer_attr_style(expr, false)?;
1777                     self.maybe_print_trailing_comment(expr.span, Some(blk.span.hi()))?;
1778                 }
1779                 _ => self.print_stmt(st)?,
1780             }
1781         }
1782
1783         self.bclose_maybe_open(blk.span, indented, close_box)?;
1784         self.ann.post(self, AnnNode::Block(blk))
1785     }
1786
1787     fn print_else(&mut self, els: Option<&ast::Expr>) -> io::Result<()> {
1788         match els {
1789             Some(_else) => {
1790                 match _else.node {
1791                     // "another else-if"
1792                     ast::ExprKind::If(ref i, ref then, ref e) => {
1793                         self.cbox(INDENT_UNIT - 1)?;
1794                         self.ibox(0)?;
1795                         self.s.word(" else if ")?;
1796                         self.print_expr_as_cond(i)?;
1797                         self.s.space()?;
1798                         self.print_block(then)?;
1799                         self.print_else(e.as_ref().map(|e| &**e))
1800                     }
1801                     // "another else-if-let"
1802                     ast::ExprKind::IfLet(ref pats, ref expr, ref then, ref e) => {
1803                         self.cbox(INDENT_UNIT - 1)?;
1804                         self.ibox(0)?;
1805                         self.s.word(" else if let ")?;
1806                         self.print_pats(pats)?;
1807                         self.s.space()?;
1808                         self.word_space("=")?;
1809                         self.print_expr_as_cond(expr)?;
1810                         self.s.space()?;
1811                         self.print_block(then)?;
1812                         self.print_else(e.as_ref().map(|e| &**e))
1813                     }
1814                     // "final else"
1815                     ast::ExprKind::Block(ref b, _) => {
1816                         self.cbox(INDENT_UNIT - 1)?;
1817                         self.ibox(0)?;
1818                         self.s.word(" else ")?;
1819                         self.print_block(b)
1820                     }
1821                     // BLEAH, constraints would be great here
1822                     _ => {
1823                         panic!("print_if saw if with weird alternative");
1824                     }
1825                 }
1826             }
1827             _ => Ok(())
1828         }
1829     }
1830
1831     pub fn print_if(&mut self, test: &ast::Expr, blk: &ast::Block,
1832                     elseopt: Option<&ast::Expr>) -> io::Result<()> {
1833         self.head("if")?;
1834         self.print_expr_as_cond(test)?;
1835         self.s.space()?;
1836         self.print_block(blk)?;
1837         self.print_else(elseopt)
1838     }
1839
1840     pub fn print_if_let(&mut self, pats: &[P<ast::Pat>], expr: &ast::Expr, blk: &ast::Block,
1841                         elseopt: Option<&ast::Expr>) -> io::Result<()> {
1842         self.head("if let")?;
1843         self.print_pats(pats)?;
1844         self.s.space()?;
1845         self.word_space("=")?;
1846         self.print_expr_as_cond(expr)?;
1847         self.s.space()?;
1848         self.print_block(blk)?;
1849         self.print_else(elseopt)
1850     }
1851
1852     pub fn print_mac(&mut self, m: &ast::Mac) -> io::Result<()> {
1853         self.print_path(&m.node.path, false, 0)?;
1854         self.s.word("!")?;
1855         match m.node.delim {
1856             MacDelimiter::Parenthesis => self.popen()?,
1857             MacDelimiter::Bracket => self.s.word("[")?,
1858             MacDelimiter::Brace => {
1859                 self.head("")?;
1860                 self.bopen()?;
1861             }
1862         }
1863         self.print_tts(m.node.stream())?;
1864         match m.node.delim {
1865             MacDelimiter::Parenthesis => self.pclose(),
1866             MacDelimiter::Bracket => self.s.word("]"),
1867             MacDelimiter::Brace => self.bclose(m.span),
1868         }
1869     }
1870
1871
1872     fn print_call_post(&mut self, args: &[P<ast::Expr>]) -> io::Result<()> {
1873         self.popen()?;
1874         self.commasep_exprs(Inconsistent, args)?;
1875         self.pclose()
1876     }
1877
1878     pub fn print_expr_maybe_paren(&mut self, expr: &ast::Expr, prec: i8) -> io::Result<()> {
1879         let needs_par = expr.precedence().order() < prec;
1880         if needs_par {
1881             self.popen()?;
1882         }
1883         self.print_expr(expr)?;
1884         if needs_par {
1885             self.pclose()?;
1886         }
1887         Ok(())
1888     }
1889
1890     /// Print an expr using syntax that's acceptable in a condition position, such as the `cond` in
1891     /// `if cond { ... }`.
1892     pub fn print_expr_as_cond(&mut self, expr: &ast::Expr) -> io::Result<()> {
1893         let needs_par = match expr.node {
1894             // These cases need parens due to the parse error observed in #26461: `if return {}`
1895             // parses as the erroneous construct `if (return {})`, not `if (return) {}`.
1896             ast::ExprKind::Closure(..) |
1897             ast::ExprKind::Ret(..) |
1898             ast::ExprKind::Break(..) => true,
1899
1900             _ => parser::contains_exterior_struct_lit(expr),
1901         };
1902
1903         if needs_par {
1904             self.popen()?;
1905         }
1906         self.print_expr(expr)?;
1907         if needs_par {
1908             self.pclose()?;
1909         }
1910         Ok(())
1911     }
1912
1913     fn print_expr_vec(&mut self, exprs: &[P<ast::Expr>],
1914                       attrs: &[Attribute]) -> io::Result<()> {
1915         self.ibox(INDENT_UNIT)?;
1916         self.s.word("[")?;
1917         self.print_inner_attributes_inline(attrs)?;
1918         self.commasep_exprs(Inconsistent, &exprs[..])?;
1919         self.s.word("]")?;
1920         self.end()
1921     }
1922
1923     fn print_expr_repeat(&mut self,
1924                          element: &ast::Expr,
1925                          count: &ast::AnonConst,
1926                          attrs: &[Attribute]) -> io::Result<()> {
1927         self.ibox(INDENT_UNIT)?;
1928         self.s.word("[")?;
1929         self.print_inner_attributes_inline(attrs)?;
1930         self.print_expr(element)?;
1931         self.word_space(";")?;
1932         self.print_expr(&count.value)?;
1933         self.s.word("]")?;
1934         self.end()
1935     }
1936
1937     fn print_expr_struct(&mut self,
1938                          path: &ast::Path,
1939                          fields: &[ast::Field],
1940                          wth: &Option<P<ast::Expr>>,
1941                          attrs: &[Attribute]) -> io::Result<()> {
1942         self.print_path(path, true, 0)?;
1943         self.s.word("{")?;
1944         self.print_inner_attributes_inline(attrs)?;
1945         self.commasep_cmnt(
1946             Consistent,
1947             &fields[..],
1948             |s, field| {
1949                 s.ibox(INDENT_UNIT)?;
1950                 if !field.is_shorthand {
1951                     s.print_ident(field.ident)?;
1952                     s.word_space(":")?;
1953                 }
1954                 s.print_expr(&field.expr)?;
1955                 s.end()
1956             },
1957             |f| f.span)?;
1958         match *wth {
1959             Some(ref expr) => {
1960                 self.ibox(INDENT_UNIT)?;
1961                 if !fields.is_empty() {
1962                     self.s.word(",")?;
1963                     self.s.space()?;
1964                 }
1965                 self.s.word("..")?;
1966                 self.print_expr(expr)?;
1967                 self.end()?;
1968             }
1969             _ => if !fields.is_empty() {
1970                 self.s.word(",")?
1971             }
1972         }
1973         self.s.word("}")?;
1974         Ok(())
1975     }
1976
1977     fn print_expr_tup(&mut self, exprs: &[P<ast::Expr>],
1978                       attrs: &[Attribute]) -> io::Result<()> {
1979         self.popen()?;
1980         self.print_inner_attributes_inline(attrs)?;
1981         self.commasep_exprs(Inconsistent, &exprs[..])?;
1982         if exprs.len() == 1 {
1983             self.s.word(",")?;
1984         }
1985         self.pclose()
1986     }
1987
1988     fn print_expr_call(&mut self,
1989                        func: &ast::Expr,
1990                        args: &[P<ast::Expr>]) -> io::Result<()> {
1991         let prec =
1992             match func.node {
1993                 ast::ExprKind::Field(..) => parser::PREC_FORCE_PAREN,
1994                 _ => parser::PREC_POSTFIX,
1995             };
1996
1997         self.print_expr_maybe_paren(func, prec)?;
1998         self.print_call_post(args)
1999     }
2000
2001     fn print_expr_method_call(&mut self,
2002                               segment: &ast::PathSegment,
2003                               args: &[P<ast::Expr>]) -> io::Result<()> {
2004         let base_args = &args[1..];
2005         self.print_expr_maybe_paren(&args[0], parser::PREC_POSTFIX)?;
2006         self.s.word(".")?;
2007         self.print_ident(segment.ident)?;
2008         if let Some(ref args) = segment.args {
2009             self.print_generic_args(args, true)?;
2010         }
2011         self.print_call_post(base_args)
2012     }
2013
2014     fn print_expr_binary(&mut self,
2015                          op: ast::BinOp,
2016                          lhs: &ast::Expr,
2017                          rhs: &ast::Expr) -> io::Result<()> {
2018         let assoc_op = AssocOp::from_ast_binop(op.node);
2019         let prec = assoc_op.precedence() as i8;
2020         let fixity = assoc_op.fixity();
2021
2022         let (left_prec, right_prec) = match fixity {
2023             Fixity::Left => (prec, prec + 1),
2024             Fixity::Right => (prec + 1, prec),
2025             Fixity::None => (prec + 1, prec + 1),
2026         };
2027
2028         let left_prec = match (&lhs.node, op.node) {
2029             // These cases need parens: `x as i32 < y` has the parser thinking that `i32 < y` is
2030             // the beginning of a path type. It starts trying to parse `x as (i32 < y ...` instead
2031             // of `(x as i32) < ...`. We need to convince it _not_ to do that.
2032             (&ast::ExprKind::Cast { .. }, ast::BinOpKind::Lt) |
2033             (&ast::ExprKind::Cast { .. }, ast::BinOpKind::Shl) => parser::PREC_FORCE_PAREN,
2034             _ => left_prec,
2035         };
2036
2037         self.print_expr_maybe_paren(lhs, left_prec)?;
2038         self.s.space()?;
2039         self.word_space(op.node.to_string())?;
2040         self.print_expr_maybe_paren(rhs, right_prec)
2041     }
2042
2043     fn print_expr_unary(&mut self,
2044                         op: ast::UnOp,
2045                         expr: &ast::Expr) -> io::Result<()> {
2046         self.s.word(ast::UnOp::to_string(op))?;
2047         self.print_expr_maybe_paren(expr, parser::PREC_PREFIX)
2048     }
2049
2050     fn print_expr_addr_of(&mut self,
2051                           mutability: ast::Mutability,
2052                           expr: &ast::Expr) -> io::Result<()> {
2053         self.s.word("&")?;
2054         self.print_mutability(mutability)?;
2055         self.print_expr_maybe_paren(expr, parser::PREC_PREFIX)
2056     }
2057
2058     pub fn print_expr(&mut self, expr: &ast::Expr) -> io::Result<()> {
2059         self.print_expr_outer_attr_style(expr, true)
2060     }
2061
2062     fn print_expr_outer_attr_style(&mut self,
2063                                   expr: &ast::Expr,
2064                                   is_inline: bool) -> io::Result<()> {
2065         self.maybe_print_comment(expr.span.lo())?;
2066
2067         let attrs = &expr.attrs;
2068         if is_inline {
2069             self.print_outer_attributes_inline(attrs)?;
2070         } else {
2071             self.print_outer_attributes(attrs)?;
2072         }
2073
2074         self.ibox(INDENT_UNIT)?;
2075         self.ann.pre(self, AnnNode::Expr(expr))?;
2076         match expr.node {
2077             ast::ExprKind::Box(ref expr) => {
2078                 self.word_space("box")?;
2079                 self.print_expr_maybe_paren(expr, parser::PREC_PREFIX)?;
2080             }
2081             ast::ExprKind::ObsoleteInPlace(ref place, ref expr) => {
2082                 let prec = AssocOp::ObsoleteInPlace.precedence() as i8;
2083                 self.print_expr_maybe_paren(place, prec + 1)?;
2084                 self.s.space()?;
2085                 self.word_space("<-")?;
2086                 self.print_expr_maybe_paren(expr, prec)?;
2087             }
2088             ast::ExprKind::Array(ref exprs) => {
2089                 self.print_expr_vec(&exprs[..], attrs)?;
2090             }
2091             ast::ExprKind::Repeat(ref element, ref count) => {
2092                 self.print_expr_repeat(element, count, attrs)?;
2093             }
2094             ast::ExprKind::Struct(ref path, ref fields, ref wth) => {
2095                 self.print_expr_struct(path, &fields[..], wth, attrs)?;
2096             }
2097             ast::ExprKind::Tup(ref exprs) => {
2098                 self.print_expr_tup(&exprs[..], attrs)?;
2099             }
2100             ast::ExprKind::Call(ref func, ref args) => {
2101                 self.print_expr_call(func, &args[..])?;
2102             }
2103             ast::ExprKind::MethodCall(ref segment, ref args) => {
2104                 self.print_expr_method_call(segment, &args[..])?;
2105             }
2106             ast::ExprKind::Binary(op, ref lhs, ref rhs) => {
2107                 self.print_expr_binary(op, lhs, rhs)?;
2108             }
2109             ast::ExprKind::Unary(op, ref expr) => {
2110                 self.print_expr_unary(op, expr)?;
2111             }
2112             ast::ExprKind::AddrOf(m, ref expr) => {
2113                 self.print_expr_addr_of(m, expr)?;
2114             }
2115             ast::ExprKind::Lit(ref lit) => {
2116                 self.print_literal(lit)?;
2117             }
2118             ast::ExprKind::Cast(ref expr, ref ty) => {
2119                 let prec = AssocOp::As.precedence() as i8;
2120                 self.print_expr_maybe_paren(expr, prec)?;
2121                 self.s.space()?;
2122                 self.word_space("as")?;
2123                 self.print_type(ty)?;
2124             }
2125             ast::ExprKind::Type(ref expr, ref ty) => {
2126                 let prec = AssocOp::Colon.precedence() as i8;
2127                 self.print_expr_maybe_paren(expr, prec)?;
2128                 self.word_space(":")?;
2129                 self.print_type(ty)?;
2130             }
2131             ast::ExprKind::If(ref test, ref blk, ref elseopt) => {
2132                 self.print_if(test, blk, elseopt.as_ref().map(|e| &**e))?;
2133             }
2134             ast::ExprKind::IfLet(ref pats, ref expr, ref blk, ref elseopt) => {
2135                 self.print_if_let(pats, expr, blk, elseopt.as_ref().map(|e| &**e))?;
2136             }
2137             ast::ExprKind::While(ref test, ref blk, opt_label) => {
2138                 if let Some(label) = opt_label {
2139                     self.print_ident(label.ident)?;
2140                     self.word_space(":")?;
2141                 }
2142                 self.head("while")?;
2143                 self.print_expr_as_cond(test)?;
2144                 self.s.space()?;
2145                 self.print_block_with_attrs(blk, attrs)?;
2146             }
2147             ast::ExprKind::WhileLet(ref pats, ref expr, ref blk, opt_label) => {
2148                 if let Some(label) = opt_label {
2149                     self.print_ident(label.ident)?;
2150                     self.word_space(":")?;
2151                 }
2152                 self.head("while let")?;
2153                 self.print_pats(pats)?;
2154                 self.s.space()?;
2155                 self.word_space("=")?;
2156                 self.print_expr_as_cond(expr)?;
2157                 self.s.space()?;
2158                 self.print_block_with_attrs(blk, attrs)?;
2159             }
2160             ast::ExprKind::ForLoop(ref pat, ref iter, ref blk, opt_label) => {
2161                 if let Some(label) = opt_label {
2162                     self.print_ident(label.ident)?;
2163                     self.word_space(":")?;
2164                 }
2165                 self.head("for")?;
2166                 self.print_pat(pat)?;
2167                 self.s.space()?;
2168                 self.word_space("in")?;
2169                 self.print_expr_as_cond(iter)?;
2170                 self.s.space()?;
2171                 self.print_block_with_attrs(blk, attrs)?;
2172             }
2173             ast::ExprKind::Loop(ref blk, opt_label) => {
2174                 if let Some(label) = opt_label {
2175                     self.print_ident(label.ident)?;
2176                     self.word_space(":")?;
2177                 }
2178                 self.head("loop")?;
2179                 self.s.space()?;
2180                 self.print_block_with_attrs(blk, attrs)?;
2181             }
2182             ast::ExprKind::Match(ref expr, ref arms) => {
2183                 self.cbox(INDENT_UNIT)?;
2184                 self.ibox(4)?;
2185                 self.word_nbsp("match")?;
2186                 self.print_expr_as_cond(expr)?;
2187                 self.s.space()?;
2188                 self.bopen()?;
2189                 self.print_inner_attributes_no_trailing_hardbreak(attrs)?;
2190                 for arm in arms {
2191                     self.print_arm(arm)?;
2192                 }
2193                 self.bclose_(expr.span, INDENT_UNIT)?;
2194             }
2195             ast::ExprKind::Closure(
2196                 capture_clause, asyncness, movability, ref decl, ref body, _) => {
2197                 self.print_movability(movability)?;
2198                 self.print_asyncness(asyncness)?;
2199                 self.print_capture_clause(capture_clause)?;
2200
2201                 self.print_fn_block_args(decl)?;
2202                 self.s.space()?;
2203                 self.print_expr(body)?;
2204                 self.end()?; // need to close a box
2205
2206                 // a box will be closed by print_expr, but we didn't want an overall
2207                 // wrapper so we closed the corresponding opening. so create an
2208                 // empty box to satisfy the close.
2209                 self.ibox(0)?;
2210             }
2211             ast::ExprKind::Block(ref blk, opt_label) => {
2212                 if let Some(label) = opt_label {
2213                     self.print_ident(label.ident)?;
2214                     self.word_space(":")?;
2215                 }
2216                 // containing cbox, will be closed by print-block at }
2217                 self.cbox(INDENT_UNIT)?;
2218                 // head-box, will be closed by print-block after {
2219                 self.ibox(0)?;
2220                 self.print_block_with_attrs(blk, attrs)?;
2221             }
2222             ast::ExprKind::Async(capture_clause, _, ref blk) => {
2223                 self.word_nbsp("async")?;
2224                 self.print_capture_clause(capture_clause)?;
2225                 self.s.space()?;
2226                 // cbox/ibox in analogy to the `ExprKind::Block` arm above
2227                 self.cbox(INDENT_UNIT)?;
2228                 self.ibox(0)?;
2229                 self.print_block_with_attrs(blk, attrs)?;
2230             }
2231             ast::ExprKind::Assign(ref lhs, ref rhs) => {
2232                 let prec = AssocOp::Assign.precedence() as i8;
2233                 self.print_expr_maybe_paren(lhs, prec + 1)?;
2234                 self.s.space()?;
2235                 self.word_space("=")?;
2236                 self.print_expr_maybe_paren(rhs, prec)?;
2237             }
2238             ast::ExprKind::AssignOp(op, ref lhs, ref rhs) => {
2239                 let prec = AssocOp::Assign.precedence() as i8;
2240                 self.print_expr_maybe_paren(lhs, prec + 1)?;
2241                 self.s.space()?;
2242                 self.s.word(op.node.to_string())?;
2243                 self.word_space("=")?;
2244                 self.print_expr_maybe_paren(rhs, prec)?;
2245             }
2246             ast::ExprKind::Field(ref expr, ident) => {
2247                 self.print_expr_maybe_paren(expr, parser::PREC_POSTFIX)?;
2248                 self.s.word(".")?;
2249                 self.print_ident(ident)?;
2250             }
2251             ast::ExprKind::Index(ref expr, ref index) => {
2252                 self.print_expr_maybe_paren(expr, parser::PREC_POSTFIX)?;
2253                 self.s.word("[")?;
2254                 self.print_expr(index)?;
2255                 self.s.word("]")?;
2256             }
2257             ast::ExprKind::Range(ref start, ref end, limits) => {
2258                 // Special case for `Range`.  `AssocOp` claims that `Range` has higher precedence
2259                 // than `Assign`, but `x .. x = x` gives a parse error instead of `x .. (x = x)`.
2260                 // Here we use a fake precedence value so that any child with lower precedence than
2261                 // a "normal" binop gets parenthesized.  (`LOr` is the lowest-precedence binop.)
2262                 let fake_prec = AssocOp::LOr.precedence() as i8;
2263                 if let Some(ref e) = *start {
2264                     self.print_expr_maybe_paren(e, fake_prec)?;
2265                 }
2266                 if limits == ast::RangeLimits::HalfOpen {
2267                     self.s.word("..")?;
2268                 } else {
2269                     self.s.word("..=")?;
2270                 }
2271                 if let Some(ref e) = *end {
2272                     self.print_expr_maybe_paren(e, fake_prec)?;
2273                 }
2274             }
2275             ast::ExprKind::Path(None, ref path) => {
2276                 self.print_path(path, true, 0)?
2277             }
2278             ast::ExprKind::Path(Some(ref qself), ref path) => {
2279                 self.print_qpath(path, qself, true)?
2280             }
2281             ast::ExprKind::Break(opt_label, ref opt_expr) => {
2282                 self.s.word("break")?;
2283                 self.s.space()?;
2284                 if let Some(label) = opt_label {
2285                     self.print_ident(label.ident)?;
2286                     self.s.space()?;
2287                 }
2288                 if let Some(ref expr) = *opt_expr {
2289                     self.print_expr_maybe_paren(expr, parser::PREC_JUMP)?;
2290                     self.s.space()?;
2291                 }
2292             }
2293             ast::ExprKind::Continue(opt_label) => {
2294                 self.s.word("continue")?;
2295                 self.s.space()?;
2296                 if let Some(label) = opt_label {
2297                     self.print_ident(label.ident)?;
2298                     self.s.space()?
2299                 }
2300             }
2301             ast::ExprKind::Ret(ref result) => {
2302                 self.s.word("return")?;
2303                 if let Some(ref expr) = *result {
2304                     self.s.word(" ")?;
2305                     self.print_expr_maybe_paren(expr, parser::PREC_JUMP)?;
2306                 }
2307             }
2308             ast::ExprKind::InlineAsm(ref a) => {
2309                 self.s.word("asm!")?;
2310                 self.popen()?;
2311                 self.print_string(&a.asm.as_str(), a.asm_str_style)?;
2312                 self.word_space(":")?;
2313
2314                 self.commasep(Inconsistent, &a.outputs, |s, out| {
2315                     let constraint = out.constraint.as_str();
2316                     let mut ch = constraint.chars();
2317                     match ch.next() {
2318                         Some('=') if out.is_rw => {
2319                             s.print_string(&format!("+{}", ch.as_str()),
2320                                            ast::StrStyle::Cooked)?
2321                         }
2322                         _ => s.print_string(&constraint, ast::StrStyle::Cooked)?
2323                     }
2324                     s.popen()?;
2325                     s.print_expr(&out.expr)?;
2326                     s.pclose()?;
2327                     Ok(())
2328                 })?;
2329                 self.s.space()?;
2330                 self.word_space(":")?;
2331
2332                 self.commasep(Inconsistent, &a.inputs, |s, &(co, ref o)| {
2333                     s.print_string(&co.as_str(), ast::StrStyle::Cooked)?;
2334                     s.popen()?;
2335                     s.print_expr(o)?;
2336                     s.pclose()?;
2337                     Ok(())
2338                 })?;
2339                 self.s.space()?;
2340                 self.word_space(":")?;
2341
2342                 self.commasep(Inconsistent, &a.clobbers,
2343                                    |s, co| {
2344                     s.print_string(&co.as_str(), ast::StrStyle::Cooked)?;
2345                     Ok(())
2346                 })?;
2347
2348                 let mut options = vec![];
2349                 if a.volatile {
2350                     options.push("volatile");
2351                 }
2352                 if a.alignstack {
2353                     options.push("alignstack");
2354                 }
2355                 if a.dialect == ast::AsmDialect::Intel {
2356                     options.push("intel");
2357                 }
2358
2359                 if !options.is_empty() {
2360                     self.s.space()?;
2361                     self.word_space(":")?;
2362                     self.commasep(Inconsistent, &options,
2363                                   |s, &co| {
2364                                       s.print_string(co, ast::StrStyle::Cooked)?;
2365                                       Ok(())
2366                                   })?;
2367                 }
2368
2369                 self.pclose()?;
2370             }
2371             ast::ExprKind::Mac(ref m) => self.print_mac(m)?,
2372             ast::ExprKind::Paren(ref e) => {
2373                 self.popen()?;
2374                 self.print_inner_attributes_inline(attrs)?;
2375                 self.print_expr(e)?;
2376                 self.pclose()?;
2377             },
2378             ast::ExprKind::Yield(ref e) => {
2379                 self.s.word("yield")?;
2380                 match *e {
2381                     Some(ref expr) => {
2382                         self.s.space()?;
2383                         self.print_expr_maybe_paren(expr, parser::PREC_JUMP)?;
2384                     }
2385                     _ => ()
2386                 }
2387             }
2388             ast::ExprKind::Try(ref e) => {
2389                 self.print_expr_maybe_paren(e, parser::PREC_POSTFIX)?;
2390                 self.s.word("?")?
2391             }
2392             ast::ExprKind::TryBlock(ref blk) => {
2393                 self.head("try")?;
2394                 self.s.space()?;
2395                 self.print_block_with_attrs(blk, attrs)?
2396             }
2397             ast::ExprKind::Err => {
2398                 self.popen()?;
2399                 self.s.word("/*ERROR*/")?;
2400                 self.pclose()?
2401             }
2402         }
2403         self.ann.post(self, AnnNode::Expr(expr))?;
2404         self.end()
2405     }
2406
2407     pub fn print_local_decl(&mut self, loc: &ast::Local) -> io::Result<()> {
2408         self.print_pat(&loc.pat)?;
2409         if let Some(ref ty) = loc.ty {
2410             self.word_space(":")?;
2411             self.print_type(ty)?;
2412         }
2413         Ok(())
2414     }
2415
2416     pub fn print_ident(&mut self, ident: ast::Ident) -> io::Result<()> {
2417         if ident.is_raw_guess() {
2418             self.s.word(format!("r#{}", ident))?;
2419         } else {
2420             self.s.word(ident.as_str().get())?;
2421         }
2422         self.ann.post(self, AnnNode::Ident(&ident))
2423     }
2424
2425     pub fn print_usize(&mut self, i: usize) -> io::Result<()> {
2426         self.s.word(i.to_string())
2427     }
2428
2429     pub fn print_name(&mut self, name: ast::Name) -> io::Result<()> {
2430         self.s.word(name.as_str().get())?;
2431         self.ann.post(self, AnnNode::Name(&name))
2432     }
2433
2434     pub fn print_for_decl(&mut self, loc: &ast::Local,
2435                           coll: &ast::Expr) -> io::Result<()> {
2436         self.print_local_decl(loc)?;
2437         self.s.space()?;
2438         self.word_space("in")?;
2439         self.print_expr(coll)
2440     }
2441
2442     fn print_path(&mut self,
2443                   path: &ast::Path,
2444                   colons_before_params: bool,
2445                   depth: usize)
2446                   -> io::Result<()>
2447     {
2448         self.maybe_print_comment(path.span.lo())?;
2449
2450         for (i, segment) in path.segments[..path.segments.len() - depth].iter().enumerate() {
2451             if i > 0 {
2452                 self.s.word("::")?
2453             }
2454             self.print_path_segment(segment, colons_before_params)?;
2455         }
2456
2457         Ok(())
2458     }
2459
2460     fn print_path_segment(&mut self,
2461                           segment: &ast::PathSegment,
2462                           colons_before_params: bool)
2463                           -> io::Result<()>
2464     {
2465         if segment.ident.name != keywords::PathRoot.name() {
2466             if segment.ident.name == keywords::DollarCrate.name() {
2467                 self.print_dollar_crate(segment.ident)?;
2468             } else {
2469                 self.print_ident(segment.ident)?;
2470             }
2471             if let Some(ref args) = segment.args {
2472                 self.print_generic_args(args, colons_before_params)?;
2473             }
2474         }
2475         Ok(())
2476     }
2477
2478     fn print_qpath(&mut self,
2479                    path: &ast::Path,
2480                    qself: &ast::QSelf,
2481                    colons_before_params: bool)
2482                    -> io::Result<()>
2483     {
2484         self.s.word("<")?;
2485         self.print_type(&qself.ty)?;
2486         if qself.position > 0 {
2487             self.s.space()?;
2488             self.word_space("as")?;
2489             let depth = path.segments.len() - qself.position;
2490             self.print_path(path, false, depth)?;
2491         }
2492         self.s.word(">")?;
2493         self.s.word("::")?;
2494         let item_segment = path.segments.last().unwrap();
2495         self.print_ident(item_segment.ident)?;
2496         match item_segment.args {
2497             Some(ref args) => self.print_generic_args(args, colons_before_params),
2498             None => Ok(()),
2499         }
2500     }
2501
2502     fn print_generic_args(&mut self,
2503                           args: &ast::GenericArgs,
2504                           colons_before_params: bool)
2505                           -> io::Result<()>
2506     {
2507         if colons_before_params {
2508             self.s.word("::")?
2509         }
2510
2511         match *args {
2512             ast::GenericArgs::AngleBracketed(ref data) => {
2513                 self.s.word("<")?;
2514
2515                 self.commasep(Inconsistent, &data.args, |s, generic_arg| {
2516                     s.print_generic_arg(generic_arg)
2517                 })?;
2518
2519                 let mut comma = data.args.len() != 0;
2520
2521                 for binding in data.bindings.iter() {
2522                     if comma {
2523                         self.word_space(",")?
2524                     }
2525                     self.print_ident(binding.ident)?;
2526                     self.s.space()?;
2527                     self.word_space("=")?;
2528                     self.print_type(&binding.ty)?;
2529                     comma = true;
2530                 }
2531
2532                 self.s.word(">")?
2533             }
2534
2535             ast::GenericArgs::Parenthesized(ref data) => {
2536                 self.s.word("(")?;
2537                 self.commasep(
2538                     Inconsistent,
2539                     &data.inputs,
2540                     |s, ty| s.print_type(ty))?;
2541                 self.s.word(")")?;
2542
2543                 if let Some(ref ty) = data.output {
2544                     self.space_if_not_bol()?;
2545                     self.word_space("->")?;
2546                     self.print_type(ty)?;
2547                 }
2548             }
2549         }
2550
2551         Ok(())
2552     }
2553
2554     pub fn print_pat(&mut self, pat: &ast::Pat) -> io::Result<()> {
2555         self.maybe_print_comment(pat.span.lo())?;
2556         self.ann.pre(self, AnnNode::Pat(pat))?;
2557         /* Pat isn't normalized, but the beauty of it
2558          is that it doesn't matter */
2559         match pat.node {
2560             PatKind::Wild => self.s.word("_")?,
2561             PatKind::Ident(binding_mode, ident, ref sub) => {
2562                 match binding_mode {
2563                     ast::BindingMode::ByRef(mutbl) => {
2564                         self.word_nbsp("ref")?;
2565                         self.print_mutability(mutbl)?;
2566                     }
2567                     ast::BindingMode::ByValue(ast::Mutability::Immutable) => {}
2568                     ast::BindingMode::ByValue(ast::Mutability::Mutable) => {
2569                         self.word_nbsp("mut")?;
2570                     }
2571                 }
2572                 self.print_ident(ident)?;
2573                 if let Some(ref p) = *sub {
2574                     self.s.word("@")?;
2575                     self.print_pat(p)?;
2576                 }
2577             }
2578             PatKind::TupleStruct(ref path, ref elts, ddpos) => {
2579                 self.print_path(path, true, 0)?;
2580                 self.popen()?;
2581                 if let Some(ddpos) = ddpos {
2582                     self.commasep(Inconsistent, &elts[..ddpos], |s, p| s.print_pat(p))?;
2583                     if ddpos != 0 {
2584                         self.word_space(",")?;
2585                     }
2586                     self.s.word("..")?;
2587                     if ddpos != elts.len() {
2588                         self.s.word(",")?;
2589                         self.commasep(Inconsistent, &elts[ddpos..], |s, p| s.print_pat(p))?;
2590                     }
2591                 } else {
2592                     self.commasep(Inconsistent, &elts[..], |s, p| s.print_pat(p))?;
2593                 }
2594                 self.pclose()?;
2595             }
2596             PatKind::Path(None, ref path) => {
2597                 self.print_path(path, true, 0)?;
2598             }
2599             PatKind::Path(Some(ref qself), ref path) => {
2600                 self.print_qpath(path, qself, false)?;
2601             }
2602             PatKind::Struct(ref path, ref fields, etc) => {
2603                 self.print_path(path, true, 0)?;
2604                 self.nbsp()?;
2605                 self.word_space("{")?;
2606                 self.commasep_cmnt(
2607                     Consistent, &fields[..],
2608                     |s, f| {
2609                         s.cbox(INDENT_UNIT)?;
2610                         if !f.node.is_shorthand {
2611                             s.print_ident(f.node.ident)?;
2612                             s.word_nbsp(":")?;
2613                         }
2614                         s.print_pat(&f.node.pat)?;
2615                         s.end()
2616                     },
2617                     |f| f.node.pat.span)?;
2618                 if etc {
2619                     if !fields.is_empty() { self.word_space(",")?; }
2620                     self.s.word("..")?;
2621                 }
2622                 self.s.space()?;
2623                 self.s.word("}")?;
2624             }
2625             PatKind::Tuple(ref elts, ddpos) => {
2626                 self.popen()?;
2627                 if let Some(ddpos) = ddpos {
2628                     self.commasep(Inconsistent, &elts[..ddpos], |s, p| s.print_pat(p))?;
2629                     if ddpos != 0 {
2630                         self.word_space(",")?;
2631                     }
2632                     self.s.word("..")?;
2633                     if ddpos != elts.len() {
2634                         self.s.word(",")?;
2635                         self.commasep(Inconsistent, &elts[ddpos..], |s, p| s.print_pat(p))?;
2636                     }
2637                 } else {
2638                     self.commasep(Inconsistent, &elts[..], |s, p| s.print_pat(p))?;
2639                     if elts.len() == 1 {
2640                         self.s.word(",")?;
2641                     }
2642                 }
2643                 self.pclose()?;
2644             }
2645             PatKind::Box(ref inner) => {
2646                 self.s.word("box ")?;
2647                 self.print_pat(inner)?;
2648             }
2649             PatKind::Ref(ref inner, mutbl) => {
2650                 self.s.word("&")?;
2651                 if mutbl == ast::Mutability::Mutable {
2652                     self.s.word("mut ")?;
2653                 }
2654                 self.print_pat(inner)?;
2655             }
2656             PatKind::Lit(ref e) => self.print_expr(&**e)?,
2657             PatKind::Range(ref begin, ref end, Spanned { node: ref end_kind, .. }) => {
2658                 self.print_expr(begin)?;
2659                 self.s.space()?;
2660                 match *end_kind {
2661                     RangeEnd::Included(RangeSyntax::DotDotDot) => self.s.word("...")?,
2662                     RangeEnd::Included(RangeSyntax::DotDotEq) => self.s.word("..=")?,
2663                     RangeEnd::Excluded => self.s.word("..")?,
2664                 }
2665                 self.print_expr(end)?;
2666             }
2667             PatKind::Slice(ref before, ref slice, ref after) => {
2668                 self.s.word("[")?;
2669                 self.commasep(Inconsistent,
2670                                    &before[..],
2671                                    |s, p| s.print_pat(p))?;
2672                 if let Some(ref p) = *slice {
2673                     if !before.is_empty() { self.word_space(",")?; }
2674                     if let PatKind::Wild = p.node {
2675                         // Print nothing
2676                     } else {
2677                         self.print_pat(p)?;
2678                     }
2679                     self.s.word("..")?;
2680                     if !after.is_empty() { self.word_space(",")?; }
2681                 }
2682                 self.commasep(Inconsistent,
2683                                    &after[..],
2684                                    |s, p| s.print_pat(p))?;
2685                 self.s.word("]")?;
2686             }
2687             PatKind::Paren(ref inner) => {
2688                 self.popen()?;
2689                 self.print_pat(inner)?;
2690                 self.pclose()?;
2691             }
2692             PatKind::Mac(ref m) => self.print_mac(m)?,
2693         }
2694         self.ann.post(self, AnnNode::Pat(pat))
2695     }
2696
2697     fn print_pats(&mut self, pats: &[P<ast::Pat>]) -> io::Result<()> {
2698         let mut first = true;
2699         for p in pats {
2700             if first {
2701                 first = false;
2702             } else {
2703                 self.s.space()?;
2704                 self.word_space("|")?;
2705             }
2706             self.print_pat(p)?;
2707         }
2708         Ok(())
2709     }
2710
2711     fn print_arm(&mut self, arm: &ast::Arm) -> io::Result<()> {
2712         // I have no idea why this check is necessary, but here it
2713         // is :(
2714         if arm.attrs.is_empty() {
2715             self.s.space()?;
2716         }
2717         self.cbox(INDENT_UNIT)?;
2718         self.ibox(0)?;
2719         self.maybe_print_comment(arm.pats[0].span.lo())?;
2720         self.print_outer_attributes(&arm.attrs)?;
2721         self.print_pats(&arm.pats)?;
2722         self.s.space()?;
2723         if let Some(ref g) = arm.guard {
2724             match g {
2725                 ast::Guard::If(ref e) => {
2726                     self.word_space("if")?;
2727                     self.print_expr(e)?;
2728                     self.s.space()?;
2729                 }
2730             }
2731         }
2732         self.word_space("=>")?;
2733
2734         match arm.body.node {
2735             ast::ExprKind::Block(ref blk, opt_label) => {
2736                 if let Some(label) = opt_label {
2737                     self.print_ident(label.ident)?;
2738                     self.word_space(":")?;
2739                 }
2740
2741                 // the block will close the pattern's ibox
2742                 self.print_block_unclosed_indent(blk, INDENT_UNIT)?;
2743
2744                 // If it is a user-provided unsafe block, print a comma after it
2745                 if let BlockCheckMode::Unsafe(ast::UserProvided) = blk.rules {
2746                     self.s.word(",")?;
2747                 }
2748             }
2749             _ => {
2750                 self.end()?; // close the ibox for the pattern
2751                 self.print_expr(&arm.body)?;
2752                 self.s.word(",")?;
2753             }
2754         }
2755         self.end() // close enclosing cbox
2756     }
2757
2758     fn print_explicit_self(&mut self, explicit_self: &ast::ExplicitSelf) -> io::Result<()> {
2759         match explicit_self.node {
2760             SelfKind::Value(m) => {
2761                 self.print_mutability(m)?;
2762                 self.s.word("self")
2763             }
2764             SelfKind::Region(ref lt, m) => {
2765                 self.s.word("&")?;
2766                 self.print_opt_lifetime(lt)?;
2767                 self.print_mutability(m)?;
2768                 self.s.word("self")
2769             }
2770             SelfKind::Explicit(ref typ, m) => {
2771                 self.print_mutability(m)?;
2772                 self.s.word("self")?;
2773                 self.word_space(":")?;
2774                 self.print_type(typ)
2775             }
2776         }
2777     }
2778
2779     pub fn print_fn(&mut self,
2780                     decl: &ast::FnDecl,
2781                     header: ast::FnHeader,
2782                     name: Option<ast::Ident>,
2783                     generics: &ast::Generics,
2784                     vis: &ast::Visibility) -> io::Result<()> {
2785         self.print_fn_header_info(header, vis)?;
2786
2787         if let Some(name) = name {
2788             self.nbsp()?;
2789             self.print_ident(name)?;
2790         }
2791         self.print_generic_params(&generics.params)?;
2792         self.print_fn_args_and_ret(decl)?;
2793         self.print_where_clause(&generics.where_clause)
2794     }
2795
2796     pub fn print_fn_args_and_ret(&mut self, decl: &ast::FnDecl)
2797         -> io::Result<()> {
2798         self.popen()?;
2799         self.commasep(Inconsistent, &decl.inputs, |s, arg| s.print_arg(arg, false))?;
2800         if decl.variadic {
2801             self.s.word(", ...")?;
2802         }
2803         self.pclose()?;
2804
2805         self.print_fn_output(decl)
2806     }
2807
2808     pub fn print_fn_block_args(
2809             &mut self,
2810             decl: &ast::FnDecl)
2811             -> io::Result<()> {
2812         self.s.word("|")?;
2813         self.commasep(Inconsistent, &decl.inputs, |s, arg| s.print_arg(arg, true))?;
2814         self.s.word("|")?;
2815
2816         if let ast::FunctionRetTy::Default(..) = decl.output {
2817             return Ok(());
2818         }
2819
2820         self.space_if_not_bol()?;
2821         self.word_space("->")?;
2822         match decl.output {
2823             ast::FunctionRetTy::Ty(ref ty) => {
2824                 self.print_type(ty)?;
2825                 self.maybe_print_comment(ty.span.lo())
2826             }
2827             ast::FunctionRetTy::Default(..) => unreachable!(),
2828         }
2829     }
2830
2831     pub fn print_movability(&mut self, movability: ast::Movability)
2832                                 -> io::Result<()> {
2833         match movability {
2834             ast::Movability::Static => self.word_space("static"),
2835             ast::Movability::Movable => Ok(()),
2836         }
2837     }
2838
2839     pub fn print_asyncness(&mut self, asyncness: ast::IsAsync)
2840                                 -> io::Result<()> {
2841         if asyncness.is_async() {
2842             self.word_nbsp("async")?;
2843         }
2844         Ok(())
2845     }
2846
2847     pub fn print_capture_clause(&mut self, capture_clause: ast::CaptureBy)
2848                                 -> io::Result<()> {
2849         match capture_clause {
2850             ast::CaptureBy::Value => self.word_space("move"),
2851             ast::CaptureBy::Ref => Ok(()),
2852         }
2853     }
2854
2855     pub fn print_type_bounds(&mut self, prefix: &'static str, bounds: &[ast::GenericBound])
2856                              -> io::Result<()> {
2857         if !bounds.is_empty() {
2858             self.s.word(prefix)?;
2859             let mut first = true;
2860             for bound in bounds {
2861                 if !(first && prefix.is_empty()) {
2862                     self.nbsp()?;
2863                 }
2864                 if first {
2865                     first = false;
2866                 } else {
2867                     self.word_space("+")?;
2868                 }
2869
2870                 match bound {
2871                     GenericBound::Trait(tref, modifier) => {
2872                         if modifier == &TraitBoundModifier::Maybe {
2873                             self.s.word("?")?;
2874                         }
2875                         self.print_poly_trait_ref(tref)?;
2876                     }
2877                     GenericBound::Outlives(lt) => self.print_lifetime(*lt)?,
2878                 }
2879             }
2880         }
2881         Ok(())
2882     }
2883
2884     pub fn print_lifetime(&mut self, lifetime: ast::Lifetime) -> io::Result<()> {
2885         self.print_name(lifetime.ident.name)
2886     }
2887
2888     pub fn print_lifetime_bounds(&mut self, lifetime: ast::Lifetime, bounds: &ast::GenericBounds)
2889         -> io::Result<()>
2890     {
2891         self.print_lifetime(lifetime)?;
2892         if !bounds.is_empty() {
2893             self.s.word(": ")?;
2894             for (i, bound) in bounds.iter().enumerate() {
2895                 if i != 0 {
2896                     self.s.word(" + ")?;
2897                 }
2898                 match bound {
2899                     ast::GenericBound::Outlives(lt) => self.print_lifetime(*lt)?,
2900                     _ => panic!(),
2901                 }
2902             }
2903         }
2904         Ok(())
2905     }
2906
2907     pub fn print_generic_params(
2908         &mut self,
2909         generic_params: &[ast::GenericParam]
2910     ) -> io::Result<()> {
2911         if generic_params.is_empty() {
2912             return Ok(());
2913         }
2914
2915         self.s.word("<")?;
2916
2917         self.commasep(Inconsistent, &generic_params, |s, param| {
2918             match param.kind {
2919                 ast::GenericParamKind::Lifetime => {
2920                     s.print_outer_attributes_inline(&param.attrs)?;
2921                     let lt = ast::Lifetime { id: param.id, ident: param.ident };
2922                     s.print_lifetime_bounds(lt, &param.bounds)
2923                 },
2924                 ast::GenericParamKind::Type { ref default } => {
2925                     s.print_outer_attributes_inline(&param.attrs)?;
2926                     s.print_ident(param.ident)?;
2927                     s.print_type_bounds(":", &param.bounds)?;
2928                     match default {
2929                         Some(ref default) => {
2930                             s.s.space()?;
2931                             s.word_space("=")?;
2932                             s.print_type(default)
2933                         }
2934                         _ => Ok(())
2935                     }
2936                 }
2937             }
2938         })?;
2939
2940         self.s.word(">")?;
2941         Ok(())
2942     }
2943
2944     pub fn print_where_clause(&mut self, where_clause: &ast::WhereClause)
2945                               -> io::Result<()> {
2946         if where_clause.predicates.is_empty() {
2947             return Ok(())
2948         }
2949
2950         self.s.space()?;
2951         self.word_space("where")?;
2952
2953         for (i, predicate) in where_clause.predicates.iter().enumerate() {
2954             if i != 0 {
2955                 self.word_space(",")?;
2956             }
2957
2958             match *predicate {
2959                 ast::WherePredicate::BoundPredicate(ast::WhereBoundPredicate {
2960                     ref bound_generic_params,
2961                     ref bounded_ty,
2962                     ref bounds,
2963                     ..
2964                 }) => {
2965                     self.print_formal_generic_params(bound_generic_params)?;
2966                     self.print_type(bounded_ty)?;
2967                     self.print_type_bounds(":", bounds)?;
2968                 }
2969                 ast::WherePredicate::RegionPredicate(ast::WhereRegionPredicate{ref lifetime,
2970                                                                                ref bounds,
2971                                                                                ..}) => {
2972                     self.print_lifetime_bounds(*lifetime, bounds)?;
2973                 }
2974                 ast::WherePredicate::EqPredicate(ast::WhereEqPredicate{ref lhs_ty,
2975                                                                        ref rhs_ty,
2976                                                                        ..}) => {
2977                     self.print_type(lhs_ty)?;
2978                     self.s.space()?;
2979                     self.word_space("=")?;
2980                     self.print_type(rhs_ty)?;
2981                 }
2982             }
2983         }
2984
2985         Ok(())
2986     }
2987
2988     pub fn print_use_tree(&mut self, tree: &ast::UseTree) -> io::Result<()> {
2989         match tree.kind {
2990             ast::UseTreeKind::Simple(rename, ..) => {
2991                 self.print_path(&tree.prefix, false, 0)?;
2992                 if let Some(rename) = rename {
2993                     self.s.space()?;
2994                     self.word_space("as")?;
2995                     self.print_ident(rename)?;
2996                 }
2997             }
2998             ast::UseTreeKind::Glob => {
2999                 if !tree.prefix.segments.is_empty() {
3000                     self.print_path(&tree.prefix, false, 0)?;
3001                     self.s.word("::")?;
3002                 }
3003                 self.s.word("*")?;
3004             }
3005             ast::UseTreeKind::Nested(ref items) => {
3006                 if tree.prefix.segments.is_empty() {
3007                     self.s.word("{")?;
3008                 } else {
3009                     self.print_path(&tree.prefix, false, 0)?;
3010                     self.s.word("::{")?;
3011                 }
3012                 self.commasep(Inconsistent, &items[..], |this, &(ref tree, _)| {
3013                     this.print_use_tree(tree)
3014                 })?;
3015                 self.s.word("}")?;
3016             }
3017         }
3018
3019         Ok(())
3020     }
3021
3022     pub fn print_mutability(&mut self,
3023                             mutbl: ast::Mutability) -> io::Result<()> {
3024         match mutbl {
3025             ast::Mutability::Mutable => self.word_nbsp("mut"),
3026             ast::Mutability::Immutable => Ok(()),
3027         }
3028     }
3029
3030     pub fn print_mt(&mut self, mt: &ast::MutTy) -> io::Result<()> {
3031         self.print_mutability(mt.mutbl)?;
3032         self.print_type(&mt.ty)
3033     }
3034
3035     pub fn print_arg(&mut self, input: &ast::Arg, is_closure: bool) -> io::Result<()> {
3036         self.ibox(INDENT_UNIT)?;
3037         match input.ty.node {
3038             ast::TyKind::Infer if is_closure => self.print_pat(&input.pat)?,
3039             _ => {
3040                 if let Some(eself) = input.to_self() {
3041                     self.print_explicit_self(&eself)?;
3042                 } else {
3043                     let invalid = if let PatKind::Ident(_, ident, _) = input.pat.node {
3044                         ident.name == keywords::Invalid.name()
3045                     } else {
3046                         false
3047                     };
3048                     if !invalid {
3049                         self.print_pat(&input.pat)?;
3050                         self.s.word(":")?;
3051                         self.s.space()?;
3052                     }
3053                     self.print_type(&input.ty)?;
3054                 }
3055             }
3056         }
3057         self.end()
3058     }
3059
3060     pub fn print_fn_output(&mut self, decl: &ast::FnDecl) -> io::Result<()> {
3061         if let ast::FunctionRetTy::Default(..) = decl.output {
3062             return Ok(());
3063         }
3064
3065         self.space_if_not_bol()?;
3066         self.ibox(INDENT_UNIT)?;
3067         self.word_space("->")?;
3068         match decl.output {
3069             ast::FunctionRetTy::Default(..) => unreachable!(),
3070             ast::FunctionRetTy::Ty(ref ty) =>
3071                 self.print_type(ty)?
3072         }
3073         self.end()?;
3074
3075         match decl.output {
3076             ast::FunctionRetTy::Ty(ref output) => self.maybe_print_comment(output.span.lo()),
3077             _ => Ok(())
3078         }
3079     }
3080
3081     pub fn print_ty_fn(&mut self,
3082                        abi: abi::Abi,
3083                        unsafety: ast::Unsafety,
3084                        decl: &ast::FnDecl,
3085                        name: Option<ast::Ident>,
3086                        generic_params: &[ast::GenericParam])
3087                        -> io::Result<()> {
3088         self.ibox(INDENT_UNIT)?;
3089         if !generic_params.is_empty() {
3090             self.s.word("for")?;
3091             self.print_generic_params(generic_params)?;
3092         }
3093         let generics = ast::Generics {
3094             params: Vec::new(),
3095             where_clause: ast::WhereClause {
3096                 id: ast::DUMMY_NODE_ID,
3097                 predicates: Vec::new(),
3098                 span: syntax_pos::DUMMY_SP,
3099             },
3100             span: syntax_pos::DUMMY_SP,
3101         };
3102         self.print_fn(decl,
3103                       ast::FnHeader { unsafety, abi, ..ast::FnHeader::default() },
3104                       name,
3105                       &generics,
3106                       &source_map::dummy_spanned(ast::VisibilityKind::Inherited))?;
3107         self.end()
3108     }
3109
3110     pub fn maybe_print_trailing_comment(&mut self, span: syntax_pos::Span,
3111                                         next_pos: Option<BytePos>)
3112         -> io::Result<()> {
3113         let cm = match self.cm {
3114             Some(cm) => cm,
3115             _ => return Ok(())
3116         };
3117         if let Some(ref cmnt) = self.next_comment() {
3118             if cmnt.style != comments::Trailing { return Ok(()) }
3119             let span_line = cm.lookup_char_pos(span.hi());
3120             let comment_line = cm.lookup_char_pos(cmnt.pos);
3121             let next = next_pos.unwrap_or_else(|| cmnt.pos + BytePos(1));
3122             if span.hi() < cmnt.pos && cmnt.pos < next && span_line.line == comment_line.line {
3123                 self.print_comment(cmnt)?;
3124             }
3125         }
3126         Ok(())
3127     }
3128
3129     pub fn print_remaining_comments(&mut self) -> io::Result<()> {
3130         // If there aren't any remaining comments, then we need to manually
3131         // make sure there is a line break at the end.
3132         if self.next_comment().is_none() {
3133             self.s.hardbreak()?;
3134         }
3135         while let Some(ref cmnt) = self.next_comment() {
3136             self.print_comment(cmnt)?;
3137         }
3138         Ok(())
3139     }
3140
3141     pub fn print_opt_abi_and_extern_if_nondefault(&mut self,
3142                                                   opt_abi: Option<Abi>)
3143         -> io::Result<()> {
3144         match opt_abi {
3145             Some(Abi::Rust) => Ok(()),
3146             Some(abi) => {
3147                 self.word_nbsp("extern")?;
3148                 self.word_nbsp(abi.to_string())
3149             }
3150             None => Ok(())
3151         }
3152     }
3153
3154     pub fn print_extern_opt_abi(&mut self,
3155                                 opt_abi: Option<Abi>) -> io::Result<()> {
3156         match opt_abi {
3157             Some(abi) => {
3158                 self.word_nbsp("extern")?;
3159                 self.word_nbsp(abi.to_string())
3160             }
3161             None => Ok(())
3162         }
3163     }
3164
3165     pub fn print_fn_header_info(&mut self,
3166                                 header: ast::FnHeader,
3167                                 vis: &ast::Visibility) -> io::Result<()> {
3168         self.s.word(visibility_qualified(vis, ""))?;
3169
3170         match header.constness.node {
3171             ast::Constness::NotConst => {}
3172             ast::Constness::Const => self.word_nbsp("const")?
3173         }
3174
3175         self.print_asyncness(header.asyncness)?;
3176         self.print_unsafety(header.unsafety)?;
3177
3178         if header.abi != Abi::Rust {
3179             self.word_nbsp("extern")?;
3180             self.word_nbsp(header.abi.to_string())?;
3181         }
3182
3183         self.s.word("fn")
3184     }
3185
3186     pub fn print_unsafety(&mut self, s: ast::Unsafety) -> io::Result<()> {
3187         match s {
3188             ast::Unsafety::Normal => Ok(()),
3189             ast::Unsafety::Unsafe => self.word_nbsp("unsafe"),
3190         }
3191     }
3192
3193     pub fn print_is_auto(&mut self, s: ast::IsAuto) -> io::Result<()> {
3194         match s {
3195             ast::IsAuto::Yes => self.word_nbsp("auto"),
3196             ast::IsAuto::No => Ok(()),
3197         }
3198     }
3199 }
3200
3201 #[cfg(test)]
3202 mod tests {
3203     use super::*;
3204
3205     use ast;
3206     use source_map;
3207     use syntax_pos;
3208     use with_globals;
3209
3210     #[test]
3211     fn test_fun_to_string() {
3212         with_globals(|| {
3213             let abba_ident = ast::Ident::from_str("abba");
3214
3215             let decl = ast::FnDecl {
3216                 inputs: Vec::new(),
3217                 output: ast::FunctionRetTy::Default(syntax_pos::DUMMY_SP),
3218                 variadic: false
3219             };
3220             let generics = ast::Generics::default();
3221             assert_eq!(
3222                 fun_to_string(
3223                     &decl,
3224                     ast::FnHeader {
3225                         unsafety: ast::Unsafety::Normal,
3226                         constness: source_map::dummy_spanned(ast::Constness::NotConst),
3227                         asyncness: ast::IsAsync::NotAsync,
3228                         abi: Abi::Rust,
3229                     },
3230                     abba_ident,
3231                     &generics
3232                 ),
3233                 "fn abba()"
3234             );
3235         })
3236     }
3237
3238     #[test]
3239     fn test_variant_to_string() {
3240         with_globals(|| {
3241             let ident = ast::Ident::from_str("principal_skinner");
3242
3243             let var = source_map::respan(syntax_pos::DUMMY_SP, ast::Variant_ {
3244                 ident,
3245                 attrs: Vec::new(),
3246                 // making this up as I go.... ?
3247                 data: ast::VariantData::Unit(ast::DUMMY_NODE_ID),
3248                 disr_expr: None,
3249             });
3250
3251             let varstr = variant_to_string(&var);
3252             assert_eq!(varstr, "principal_skinner");
3253         })
3254     }
3255 }