src/librustc_errors/lib.rs

   1 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 #![crate_name = "rustc_errors"]
  12 #![unstable(feature = "rustc_private", issue = "27812")]
  13 #![crate_type = "dylib"]
  14 #![crate_type = "rlib"]
  15 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
  16       html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
  17       html_root_url = "https://doc.rust-lang.org/nightly/")]
  18 #![cfg_attr(not(stage0), deny(warnings))]
  19
  20 #![feature(custom_attribute)]
  21 #![allow(unused_attributes)]
  22 #![feature(rustc_private)]
  23 #![feature(staged_api)]
  24 #![feature(question_mark)]
  25 #![feature(range_contains)]
  26 #![feature(libc)]
  27 #![feature(unicode)]
  28
  29 extern crate serialize;
  30 extern crate term;
  31 #[macro_use] extern crate log;
  32 #[macro_use] extern crate libc;
  33 extern crate rustc_unicode;
  34 extern crate serialize as rustc_serialize; // used by deriving
  35 extern crate syntax_pos;
  36
  37 pub use emitter::ColorConfig;
  38
  39 use self::Level::*;
  40 use self::RenderSpan::*;
  41
  42 use emitter::{Emitter, EmitterWriter};
  43
  44 use std::cell::{RefCell, Cell};
  45 use std::{error, fmt};
  46 use std::rc::Rc;
  47 use std::thread::panicking;
  48
  49 pub mod emitter;
  50 pub mod snippet;
  51 pub mod registry;
  52 pub mod styled_buffer;
  53
  54 use syntax_pos::{BytePos, Loc, FileLinesResult, FileName, MultiSpan, Span, NO_EXPANSION };
  55 use syntax_pos::{MacroBacktrace};
  56
  57 #[derive(Clone)]
  58 pub enum RenderSpan {
  59     /// A FullSpan renders with both with an initial line for the
  60     /// message, prefixed by file:linenum, followed by a summary of
  61     /// the source code covered by the span.
  62     FullSpan(MultiSpan),
  63
  64     /// A suggestion renders with both with an initial line for the
  65     /// message, prefixed by file:linenum, followed by a summary
  66     /// of hypothetical source code, where each `String` is spliced
  67     /// into the lines in place of the code covered by each span.
  68     Suggestion(CodeSuggestion),
  69 }
  70
  71 #[derive(Clone)]
  72 pub struct CodeSuggestion {
  73     pub msp: MultiSpan,
  74     pub substitutes: Vec<String>,
  75 }
  76
  77 pub trait CodeMapper {
  78     fn lookup_char_pos(&self, pos: BytePos) -> Loc;
  79     fn span_to_lines(&self, sp: Span) -> FileLinesResult;
  80     fn span_to_string(&self, sp: Span) -> String;
  81     fn span_to_filename(&self, sp: Span) -> FileName;
  82     fn macro_backtrace(&self, span: Span) -> Vec<MacroBacktrace>;
  83 }
  84
  85 impl CodeSuggestion {
  86     /// Returns the assembled code suggestion.
  87     pub fn splice_lines(&self, cm: &CodeMapper) -> String {
  88         use syntax_pos::{CharPos, Loc, Pos};
  89
  90         fn push_trailing(buf: &mut String, line_opt: Option<&str>,
  91                          lo: &Loc, hi_opt: Option<&Loc>) {
  92             let (lo, hi_opt) = (lo.col.to_usize(), hi_opt.map(|hi|hi.col.to_usize()));
  93             if let Some(line) = line_opt {
  94                 if line.len() > lo {
  95                     buf.push_str(match hi_opt {
  96                         Some(hi) => &line[lo..hi],
  97                         None => &line[lo..],
  98                     });
  99                 }
 100                 if let None = hi_opt {
 101                     buf.push('\n');
 102                 }
 103             }
 104         }
 105
 106         let mut primary_spans = self.msp.primary_spans().to_owned();
 107
 108         assert_eq!(primary_spans.len(), self.substitutes.len());
 109         if primary_spans.is_empty() {
 110             return format!("");
 111         }
 112
 113         // Assumption: all spans are in the same file, and all spans
 114         // are disjoint. Sort in ascending order.
 115         primary_spans.sort_by_key(|sp| sp.lo);
 116
 117         // Find the bounding span.
 118         let lo = primary_spans.iter().map(|sp| sp.lo).min().unwrap();
 119         let hi = primary_spans.iter().map(|sp| sp.hi).min().unwrap();
 120         let bounding_span = Span { lo: lo, hi: hi, expn_id: NO_EXPANSION };
 121         let lines = cm.span_to_lines(bounding_span).unwrap();
 122         assert!(!lines.lines.is_empty());
 123
 124         // To build up the result, we do this for each span:
 125         // - push the line segment trailing the previous span
 126         //   (at the beginning a "phantom" span pointing at the start of the line)
 127         // - push lines between the previous and current span (if any)
 128         // - if the previous and current span are not on the same line
 129         //   push the line segment leading up to the current span
 130         // - splice in the span substitution
 131         //
 132         // Finally push the trailing line segment of the last span
 133         let fm = &lines.file;
 134         let mut prev_hi = cm.lookup_char_pos(bounding_span.lo);
 135         prev_hi.col = CharPos::from_usize(0);
 136
 137         let mut prev_line = fm.get_line(lines.lines[0].line_index);
 138         let mut buf = String::new();
 139
 140         for (sp, substitute) in primary_spans.iter().zip(self.substitutes.iter()) {
 141             let cur_lo = cm.lookup_char_pos(sp.lo);
 142             if prev_hi.line == cur_lo.line {
 143                 push_trailing(&mut buf, prev_line, &prev_hi, Some(&cur_lo));
 144             } else {
 145                 push_trailing(&mut buf, prev_line, &prev_hi, None);
 146                 // push lines between the previous and current span (if any)
 147                 for idx in prev_hi.line..(cur_lo.line - 1) {
 148                     if let Some(line) = fm.get_line(idx) {
 149                         buf.push_str(line);
 150                         buf.push('\n');
 151                     }
 152                 }
 153                 if let Some(cur_line) = fm.get_line(cur_lo.line - 1) {
 154                     buf.push_str(&cur_line[.. cur_lo.col.to_usize()]);
 155                 }
 156             }
 157             buf.push_str(substitute);
 158             prev_hi = cm.lookup_char_pos(sp.hi);
 159             prev_line = fm.get_line(prev_hi.line - 1);
 160         }
 161         push_trailing(&mut buf, prev_line, &prev_hi, None);
 162         // remove trailing newline
 163         buf.pop();
 164         buf
 165     }
 166 }
 167
 168 /// Used as a return value to signify a fatal error occurred. (It is also
 169 /// used as the argument to panic at the moment, but that will eventually
 170 /// not be true.)
 171 #[derive(Copy, Clone, Debug)]
 172 #[must_use]
 173 pub struct FatalError;
 174
 175 impl fmt::Display for FatalError {
 176     fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
 177         write!(f, "parser fatal error")
 178     }
 179 }
 180
 181 impl error::Error for FatalError {
 182     fn description(&self) -> &str {
 183         "The parser has encountered a fatal error"
 184     }
 185 }
 186
 187 /// Signifies that the compiler died with an explicit call to `.bug`
 188 /// or `.span_bug` rather than a failed assertion, etc.
 189 #[derive(Copy, Clone, Debug)]
 190 pub struct ExplicitBug;
 191
 192 impl fmt::Display for ExplicitBug {
 193     fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
 194         write!(f, "parser internal bug")
 195     }
 196 }
 197
 198 impl error::Error for ExplicitBug {
 199     fn description(&self) -> &str {
 200         "The parser has encountered an internal bug"
 201     }
 202 }
 203
 204 /// Used for emitting structured error messages and other diagnostic information.
 205 #[must_use]
 206 #[derive(Clone)]
 207 pub struct DiagnosticBuilder<'a> {
 208     handler: &'a Handler,
 209     pub level: Level,
 210     pub message: String,
 211     pub code: Option<String>,
 212     pub span: MultiSpan,
 213     pub children: Vec<SubDiagnostic>,
 214 }
 215
 216 /// For example a note attached to an error.
 217 #[derive(Clone)]
 218 pub struct SubDiagnostic {
 219     pub level: Level,
 220     pub message: String,
 221     pub span: MultiSpan,
 222     pub render_span: Option<RenderSpan>,
 223 }
 224
 225 impl<'a> DiagnosticBuilder<'a> {
 226     /// Emit the diagnostic.
 227     pub fn emit(&mut self) {
 228         if self.cancelled() {
 229             return;
 230         }
 231
 232         self.handler.emitter.borrow_mut().emit(&self);
 233         self.cancel();
 234         self.handler.panic_if_treat_err_as_bug();
 235
 236         // if self.is_fatal() {
 237         //     panic!(FatalError);
 238         // }
 239     }
 240
 241     /// Cancel the diagnostic (a structured diagnostic must either be emitted or
 242     /// cancelled or it will panic when dropped).
 243     /// BEWARE: if this DiagnosticBuilder is an error, then creating it will
 244     /// bump the error count on the Handler and cancelling it won't undo that.
 245     /// If you want to decrement the error count you should use `Handler::cancel`.
 246     pub fn cancel(&mut self) {
 247         self.level = Level::Cancelled;
 248     }
 249
 250     pub fn cancelled(&self) -> bool {
 251         self.level == Level::Cancelled
 252     }
 253
 254     pub fn is_fatal(&self) -> bool {
 255         self.level == Level::Fatal
 256     }
 257
 258     /// Add a span/label to be included in the resulting snippet.
 259     /// This is pushed onto the `MultiSpan` that was created when the
 260     /// diagnostic was first built. If you don't call this function at
 261     /// all, and you just supplied a `Span` to create the diagnostic,
 262     /// then the snippet will just include that `Span`, which is
 263     /// called the primary span.
 264     pub fn span_label(&mut self, span: Span, label: &fmt::Display)
 265                       -> &mut DiagnosticBuilder<'a> {
 266         self.span.push_span_label(span, format!("{}", label));
 267         self
 268     }
 269
 270     pub fn note_expected_found(&mut self,
 271                                label: &fmt::Display,
 272                                expected: &fmt::Display,
 273                                found: &fmt::Display)
 274                                -> &mut DiagnosticBuilder<'a>
 275     {
 276         // For now, just attach these as notes
 277         self.note(&format!("expected {} `{}`", label, expected));
 278         self.note(&format!("   found {} `{}`", label, found));
 279         self
 280     }
 281
 282     pub fn note(&mut self, msg: &str) -> &mut DiagnosticBuilder<'a> {
 283         self.sub(Level::Note, msg, MultiSpan::new(), None);
 284         self
 285     }
 286     pub fn span_note<S: Into<MultiSpan>>(&mut self,
 287                                          sp: S,
 288                                          msg: &str)
 289                                          -> &mut DiagnosticBuilder<'a> {
 290         self.sub(Level::Note, msg, sp.into(), None);
 291         self
 292     }
 293     pub fn warn(&mut self, msg: &str) -> &mut DiagnosticBuilder<'a> {
 294         self.sub(Level::Warning, msg, MultiSpan::new(), None);
 295         self
 296     }
 297     pub fn span_warn<S: Into<MultiSpan>>(&mut self,
 298                                          sp: S,
 299                                          msg: &str)
 300                                          -> &mut DiagnosticBuilder<'a> {
 301         self.sub(Level::Warning, msg, sp.into(), None);
 302         self
 303     }
 304     pub fn help(&mut self , msg: &str) -> &mut DiagnosticBuilder<'a> {
 305         self.sub(Level::Help, msg, MultiSpan::new(), None);
 306         self
 307     }
 308     pub fn span_help<S: Into<MultiSpan>>(&mut self,
 309                                          sp: S,
 310                                          msg: &str)
 311                                          -> &mut DiagnosticBuilder<'a> {
 312         self.sub(Level::Help, msg, sp.into(), None);
 313         self
 314     }
 315     /// Prints out a message with a suggested edit of the code.
 316     ///
 317     /// See `diagnostic::RenderSpan::Suggestion` for more information.
 318     pub fn span_suggestion<S: Into<MultiSpan>>(&mut self,
 319                                                sp: S,
 320                                                msg: &str,
 321                                                suggestion: String)
 322                                                -> &mut DiagnosticBuilder<'a> {
 323         self.sub(Level::Help, msg, MultiSpan::new(), Some(Suggestion(CodeSuggestion {
 324             msp: sp.into(),
 325             substitutes: vec![suggestion],
 326         })));
 327         self
 328     }
 329
 330     pub fn set_span<S: Into<MultiSpan>>(&mut self, sp: S) -> &mut Self {
 331         self.span = sp.into();
 332         self
 333     }
 334
 335     pub fn code(&mut self, s: String) -> &mut Self {
 336         self.code = Some(s);
 337         self
 338     }
 339
 340     pub fn message(&self) -> &str {
 341         &self.message
 342     }
 343
 344     pub fn level(&self) -> Level {
 345         self.level
 346     }
 347
 348     /// Convenience function for internal use, clients should use one of the
 349     /// struct_* methods on Handler.
 350     fn new(handler: &'a Handler,
 351            level: Level,
 352            message: &str) -> DiagnosticBuilder<'a> {
 353         DiagnosticBuilder::new_with_code(handler, level, None, message)
 354     }
 355
 356     /// Convenience function for internal use, clients should use one of the
 357     /// struct_* methods on Handler.
 358     fn new_with_code(handler: &'a Handler,
 359            level: Level,
 360            code: Option<String>,
 361            message: &str) -> DiagnosticBuilder<'a> {
 362         DiagnosticBuilder {
 363             handler: handler,
 364             level: level,
 365             message: message.to_owned(),
 366             code: code,
 367             span: MultiSpan::new(),
 368             children: vec![],
 369         }
 370     }
 371
 372     /// Convenience function for internal use, clients should use one of the
 373     /// public methods above.
 374     fn sub(&mut self,
 375            level: Level,
 376            message: &str,
 377            span: MultiSpan,
 378            render_span: Option<RenderSpan>) {
 379         let sub = SubDiagnostic {
 380             level: level,
 381             message: message.to_owned(),
 382             span: span,
 383             render_span: render_span,
 384         };
 385         self.children.push(sub);
 386     }
 387 }
 388
 389 impl<'a> fmt::Debug for DiagnosticBuilder<'a> {
 390     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 391         self.message.fmt(f)
 392     }
 393 }
 394
 395 /// Destructor bomb - a DiagnosticBuilder must be either emitted or cancelled or
 396 /// we emit a bug.
 397 impl<'a> Drop for DiagnosticBuilder<'a> {
 398     fn drop(&mut self) {
 399         if !panicking() && !self.cancelled() {
 400             let mut db = DiagnosticBuilder::new(self.handler,
 401                                                 Bug,
 402                                                 "Error constructed but not emitted");
 403             db.emit();
 404             panic!();
 405         }
 406     }
 407 }
 408
 409 /// A handler deals with errors; certain errors
 410 /// (fatal, bug, unimpl) may cause immediate exit,
 411 /// others log errors for later reporting.
 412 pub struct Handler {
 413     err_count: Cell<usize>,
 414     emitter: RefCell<Box<Emitter>>,
 415     pub can_emit_warnings: bool,
 416     treat_err_as_bug: bool,
 417     continue_after_error: Cell<bool>,
 418     delayed_span_bug: RefCell<Option<(MultiSpan, String)>>,
 419 }
 420
 421 impl Handler {
 422     pub fn with_tty_emitter(color_config: ColorConfig,
 423                             can_emit_warnings: bool,
 424                             treat_err_as_bug: bool,
 425                             cm: Option<Rc<CodeMapper>>)
 426                             -> Handler {
 427         let emitter = Box::new(EmitterWriter::stderr(color_config, cm));
 428         Handler::with_emitter(can_emit_warnings, treat_err_as_bug, emitter)
 429     }
 430
 431     pub fn with_emitter(can_emit_warnings: bool,
 432                         treat_err_as_bug: bool,
 433                         e: Box<Emitter>) -> Handler {
 434         Handler {
 435             err_count: Cell::new(0),
 436             emitter: RefCell::new(e),
 437             can_emit_warnings: can_emit_warnings,
 438             treat_err_as_bug: treat_err_as_bug,
 439             continue_after_error: Cell::new(true),
 440             delayed_span_bug: RefCell::new(None),
 441         }
 442     }
 443
 444     pub fn set_continue_after_error(&self, continue_after_error: bool) {
 445         self.continue_after_error.set(continue_after_error);
 446     }
 447
 448     pub fn struct_dummy<'a>(&'a self) -> DiagnosticBuilder<'a> {
 449         DiagnosticBuilder::new(self, Level::Cancelled, "")
 450     }
 451
 452     pub fn struct_span_warn<'a, S: Into<MultiSpan>>(&'a self,
 453                                                     sp: S,
 454                                                     msg: &str)
 455                                                     -> DiagnosticBuilder<'a> {
 456         let mut result = DiagnosticBuilder::new(self, Level::Warning, msg);
 457         result.set_span(sp);
 458         if !self.can_emit_warnings {
 459             result.cancel();
 460         }
 461         result
 462     }
 463     pub fn struct_span_warn_with_code<'a, S: Into<MultiSpan>>(&'a self,
 464                                                               sp: S,
 465                                                               msg: &str,
 466                                                               code: &str)
 467                                                               -> DiagnosticBuilder<'a> {
 468         let mut result = DiagnosticBuilder::new(self, Level::Warning, msg);
 469         result.set_span(sp);
 470         result.code(code.to_owned());
 471         if !self.can_emit_warnings {
 472             result.cancel();
 473         }
 474         result
 475     }
 476     pub fn struct_warn<'a>(&'a self, msg: &str) -> DiagnosticBuilder<'a> {
 477         let mut result = DiagnosticBuilder::new(self, Level::Warning, msg);
 478         if !self.can_emit_warnings {
 479             result.cancel();
 480         }
 481         result
 482     }
 483     pub fn struct_span_err<'a, S: Into<MultiSpan>>(&'a self,
 484                                                    sp: S,
 485                                                    msg: &str)
 486                                                    -> DiagnosticBuilder<'a> {
 487         self.bump_err_count();
 488         let mut result = DiagnosticBuilder::new(self, Level::Error, msg);
 489         result.set_span(sp);
 490         result
 491     }
 492     pub fn struct_span_err_with_code<'a, S: Into<MultiSpan>>(&'a self,
 493                                                              sp: S,
 494                                                              msg: &str,
 495                                                              code: &str)
 496                                                              -> DiagnosticBuilder<'a> {
 497         self.bump_err_count();
 498         let mut result = DiagnosticBuilder::new(self, Level::Error, msg);
 499         result.set_span(sp);
 500         result.code(code.to_owned());
 501         result
 502     }
 503     pub fn struct_err<'a>(&'a self, msg: &str) -> DiagnosticBuilder<'a> {
 504         self.bump_err_count();
 505         DiagnosticBuilder::new(self, Level::Error, msg)
 506     }
 507     pub fn struct_span_fatal<'a, S: Into<MultiSpan>>(&'a self,
 508                                                      sp: S,
 509                                                      msg: &str)
 510                                                      -> DiagnosticBuilder<'a> {
 511         self.bump_err_count();
 512         let mut result = DiagnosticBuilder::new(self, Level::Fatal, msg);
 513         result.set_span(sp);
 514         result
 515     }
 516     pub fn struct_span_fatal_with_code<'a, S: Into<MultiSpan>>(&'a self,
 517                                                                sp: S,
 518                                                                msg: &str,
 519                                                                code: &str)
 520                                                                -> DiagnosticBuilder<'a> {
 521         self.bump_err_count();
 522         let mut result = DiagnosticBuilder::new(self, Level::Fatal, msg);
 523         result.set_span(sp);
 524         result.code(code.to_owned());
 525         result
 526     }
 527     pub fn struct_fatal<'a>(&'a self, msg: &str) -> DiagnosticBuilder<'a> {
 528         self.bump_err_count();
 529         DiagnosticBuilder::new(self, Level::Fatal, msg)
 530     }
 531
 532     pub fn cancel(&self, err: &mut DiagnosticBuilder) {
 533         if err.level == Level::Error || err.level == Level::Fatal {
 534             self.err_count.set(
 535                 self.err_count.get().checked_sub(1)
 536                     .expect("cancelled an error but err_count is 0")
 537             );
 538         }
 539         err.cancel();
 540     }
 541
 542     fn panic_if_treat_err_as_bug(&self) {
 543         if self.treat_err_as_bug {
 544             panic!("encountered error with `-Z treat_err_as_bug");
 545         }
 546     }
 547
 548     pub fn span_fatal<S: Into<MultiSpan>>(&self, sp: S, msg: &str)
 549                                           -> FatalError {
 550         self.emit(&sp.into(), msg, Fatal);
 551         self.bump_err_count();
 552         self.panic_if_treat_err_as_bug();
 553         return FatalError;
 554     }
 555     pub fn span_fatal_with_code<S: Into<MultiSpan>>(&self, sp: S, msg: &str, code: &str)
 556                                                     -> FatalError {
 557         self.emit_with_code(&sp.into(), msg, code, Fatal);
 558         self.bump_err_count();
 559         self.panic_if_treat_err_as_bug();
 560         return FatalError;
 561     }
 562     pub fn span_err<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
 563         self.emit(&sp.into(), msg, Error);
 564         self.bump_err_count();
 565         self.panic_if_treat_err_as_bug();
 566     }
 567     pub fn span_err_with_code<S: Into<MultiSpan>>(&self, sp: S, msg: &str, code: &str) {
 568         self.emit_with_code(&sp.into(), msg, code, Error);
 569         self.bump_err_count();
 570         self.panic_if_treat_err_as_bug();
 571     }
 572     pub fn span_warn<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
 573         self.emit(&sp.into(), msg, Warning);
 574     }
 575     pub fn span_warn_with_code<S: Into<MultiSpan>>(&self, sp: S, msg: &str, code: &str) {
 576         self.emit_with_code(&sp.into(), msg, code, Warning);
 577     }
 578     pub fn span_bug<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
 579         self.emit(&sp.into(), msg, Bug);
 580         panic!(ExplicitBug);
 581     }
 582     pub fn delay_span_bug<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
 583         let mut delayed = self.delayed_span_bug.borrow_mut();
 584         *delayed = Some((sp.into(), msg.to_string()));
 585     }
 586     pub fn span_bug_no_panic<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
 587         self.emit(&sp.into(), msg, Bug);
 588         self.bump_err_count();
 589     }
 590     pub fn span_note_without_error<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
 591         self.emit(&sp.into(), msg, Note);
 592     }
 593     pub fn span_unimpl<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
 594         self.span_bug(sp, &format!("unimplemented {}", msg));
 595     }
 596     pub fn fatal(&self, msg: &str) -> FatalError {
 597         if self.treat_err_as_bug {
 598             self.bug(msg);
 599         }
 600         let mut db = DiagnosticBuilder::new(self,
 601                                             Fatal,
 602                                             msg);
 603         db.emit();
 604         self.bump_err_count();
 605         FatalError
 606     }
 607     pub fn err(&self, msg: &str) {
 608         if self.treat_err_as_bug {
 609             self.bug(msg);
 610         }
 611         let mut db = DiagnosticBuilder::new(self,
 612                                             Error,
 613                                             msg);
 614         db.emit();
 615         self.bump_err_count();
 616     }
 617     pub fn warn(&self, msg: &str) {
 618         let mut db = DiagnosticBuilder::new(self,
 619                                             Warning,
 620                                             msg);
 621         db.emit();
 622     }
 623     pub fn note_without_error(&self, msg: &str) {
 624         let mut db = DiagnosticBuilder::new(self,
 625                                             Note,
 626                                             msg);
 627         db.emit();
 628     }
 629     pub fn bug(&self, msg: &str) -> ! {
 630         let mut db = DiagnosticBuilder::new(self,
 631                                             Bug,
 632                                             msg);
 633         db.emit();
 634         panic!(ExplicitBug);
 635     }
 636     pub fn unimpl(&self, msg: &str) -> ! {
 637         self.bug(&format!("unimplemented {}", msg));
 638     }
 639
 640     pub fn bump_err_count(&self) {
 641         self.err_count.set(self.err_count.get() + 1);
 642     }
 643
 644     pub fn err_count(&self) -> usize {
 645         self.err_count.get()
 646     }
 647
 648     pub fn has_errors(&self) -> bool {
 649         self.err_count.get() > 0
 650     }
 651     pub fn abort_if_errors(&self) {
 652         let s;
 653         match self.err_count.get() {
 654             0 => {
 655                 let delayed_bug = self.delayed_span_bug.borrow();
 656                 match *delayed_bug {
 657                     Some((ref span, ref errmsg)) => {
 658                         self.span_bug(span.clone(), errmsg);
 659                     },
 660                     _ => {}
 661                 }
 662
 663                 return;
 664             }
 665             1 => s = "aborting due to previous error".to_string(),
 666             _  => {
 667                 s = format!("aborting due to {} previous errors",
 668                             self.err_count.get());
 669             }
 670         }
 671
 672         panic!(self.fatal(&s));
 673     }
 674     pub fn emit(&self,
 675                 msp: &MultiSpan,
 676                 msg: &str,
 677                 lvl: Level) {
 678         if lvl == Warning && !self.can_emit_warnings { return }
 679         let mut db = DiagnosticBuilder::new(self, lvl, msg);
 680         db.set_span(msp.clone());
 681         db.emit();
 682         if !self.continue_after_error.get() { self.abort_if_errors(); }
 683     }
 684     pub fn emit_with_code(&self,
 685                           msp: &MultiSpan,
 686                           msg: &str,
 687                           code: &str,
 688                           lvl: Level) {
 689         if lvl == Warning && !self.can_emit_warnings { return }
 690         let mut db = DiagnosticBuilder::new_with_code(self,
 691                                                       lvl,
 692                                                       Some(code.to_owned()),
 693                                                       msg);
 694         db.set_span(msp.clone());
 695         db.emit();
 696         if !self.continue_after_error.get() { self.abort_if_errors(); }
 697     }
 698 }
 699
 700
 701 #[derive(Copy, PartialEq, Clone, Debug)]
 702 pub enum Level {
 703     Bug,
 704     Fatal,
 705     // An error which while not immediately fatal, should stop the compiler
 706     // progressing beyond the current phase.
 707     PhaseFatal,
 708     Error,
 709     Warning,
 710     Note,
 711     Help,
 712     Cancelled,
 713 }
 714
 715 impl fmt::Display for Level {
 716     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 717         self.to_str().fmt(f)
 718     }
 719 }
 720
 721 impl Level {
 722     pub fn color(self) -> term::color::Color {
 723         match self {
 724             Bug | Fatal | PhaseFatal | Error => term::color::BRIGHT_RED,
 725             Warning => term::color::YELLOW,
 726             Note => term::color::BRIGHT_GREEN,
 727             Help => term::color::BRIGHT_CYAN,
 728             Cancelled => unreachable!(),
 729         }
 730     }
 731
 732     pub fn to_str(self) -> &'static str {
 733         match self {
 734             Bug => "error: internal compiler error",
 735             Fatal | PhaseFatal | Error => "error",
 736             Warning => "warning",
 737             Note => "note",
 738             Help => "help",
 739             Cancelled => panic!("Shouldn't call on cancelled error"),
 740         }
 741     }
 742 }
 743
 744 pub fn expect<T, M>(diag: &Handler, opt: Option<T>, msg: M) -> T where
 745     M: FnOnce() -> String,
 746 {
 747     match opt {
 748         Some(t) => t,
 749         None => diag.bug(&msg()),
 750     }
 751 }