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 #![deny(warnings)]
  19
  20 #![feature(custom_attribute)]
  21 #![allow(unused_attributes)]
  22 #![feature(rustc_private)]
  23 #![feature(staged_api)]
  24 #![feature(range_contains)]
  25 #![feature(libc)]
  26
  27 extern crate term;
  28 extern crate libc;
  29 extern crate syntax_pos;
  30
  31 pub use emitter::ColorConfig;
  32
  33 use self::Level::*;
  34
  35 use emitter::{Emitter, EmitterWriter};
  36
  37 use std::cell::{RefCell, Cell};
  38 use std::{error, fmt};
  39 use std::rc::Rc;
  40
  41 pub mod diagnostic;
  42 pub mod diagnostic_builder;
  43 pub mod emitter;
  44 pub mod snippet;
  45 pub mod registry;
  46 pub mod styled_buffer;
  47 mod lock;
  48
  49 use syntax_pos::{BytePos, Loc, FileLinesResult, FileName, MultiSpan, Span, NO_EXPANSION};
  50 use syntax_pos::MacroBacktrace;
  51
  52 #[derive(Clone, Debug, PartialEq)]
  53 pub enum RenderSpan {
  54     /// A FullSpan renders with both with an initial line for the
  55     /// message, prefixed by file:linenum, followed by a summary of
  56     /// the source code covered by the span.
  57     FullSpan(MultiSpan),
  58
  59     /// A suggestion renders with both with an initial line for the
  60     /// message, prefixed by file:linenum, followed by a summary
  61     /// of hypothetical source code, where each `String` is spliced
  62     /// into the lines in place of the code covered by each span.
  63     Suggestion(CodeSuggestion),
  64 }
  65
  66 #[derive(Clone, Debug, PartialEq)]
  67 pub struct CodeSuggestion {
  68     pub msp: MultiSpan,
  69     pub substitutes: Vec<String>,
  70 }
  71
  72 pub trait CodeMapper {
  73     fn lookup_char_pos(&self, pos: BytePos) -> Loc;
  74     fn span_to_lines(&self, sp: Span) -> FileLinesResult;
  75     fn span_to_string(&self, sp: Span) -> String;
  76     fn span_to_filename(&self, sp: Span) -> FileName;
  77     fn macro_backtrace(&self, span: Span) -> Vec<MacroBacktrace>;
  78     fn merge_spans(&self, sp_lhs: Span, sp_rhs: Span) -> Option<Span>;
  79 }
  80
  81 impl CodeSuggestion {
  82     /// Returns the assembled code suggestion.
  83     pub fn splice_lines(&self, cm: &CodeMapper) -> String {
  84         use syntax_pos::{CharPos, Loc, Pos};
  85
  86         fn push_trailing(buf: &mut String,
  87                          line_opt: Option<&str>,
  88                          lo: &Loc,
  89                          hi_opt: Option<&Loc>) {
  90             let (lo, hi_opt) = (lo.col.to_usize(), hi_opt.map(|hi| hi.col.to_usize()));
  91             if let Some(line) = line_opt {
  92                 if line.len() > lo {
  93                     buf.push_str(match hi_opt {
  94                         Some(hi) => &line[lo..hi],
  95                         None => &line[lo..],
  96                     });
  97                 }
  98                 if let None = hi_opt {
  99                     buf.push('\n');
 100                 }
 101             }
 102         }
 103
 104         let mut primary_spans = self.msp.primary_spans().to_owned();
 105
 106         assert_eq!(primary_spans.len(), self.substitutes.len());
 107         if primary_spans.is_empty() {
 108             return format!("");
 109         }
 110
 111         // Assumption: all spans are in the same file, and all spans
 112         // are disjoint. Sort in ascending order.
 113         primary_spans.sort_by_key(|sp| sp.lo);
 114
 115         // Find the bounding span.
 116         let lo = primary_spans.iter().map(|sp| sp.lo).min().unwrap();
 117         let hi = primary_spans.iter().map(|sp| sp.hi).min().unwrap();
 118         let bounding_span = Span {
 119             lo: lo,
 120             hi: hi,
 121             expn_id: NO_EXPANSION,
 122         };
 123         let lines = cm.span_to_lines(bounding_span).unwrap();
 124         assert!(!lines.lines.is_empty());
 125
 126         // To build up the result, we do this for each span:
 127         // - push the line segment trailing the previous span
 128         //   (at the beginning a "phantom" span pointing at the start of the line)
 129         // - push lines between the previous and current span (if any)
 130         // - if the previous and current span are not on the same line
 131         //   push the line segment leading up to the current span
 132         // - splice in the span substitution
 133         //
 134         // Finally push the trailing line segment of the last span
 135         let fm = &lines.file;
 136         let mut prev_hi = cm.lookup_char_pos(bounding_span.lo);
 137         prev_hi.col = CharPos::from_usize(0);
 138
 139         let mut prev_line = fm.get_line(lines.lines[0].line_index);
 140         let mut buf = String::new();
 141
 142         for (sp, substitute) in primary_spans.iter().zip(self.substitutes.iter()) {
 143             let cur_lo = cm.lookup_char_pos(sp.lo);
 144             if prev_hi.line == cur_lo.line {
 145                 push_trailing(&mut buf, prev_line, &prev_hi, Some(&cur_lo));
 146             } else {
 147                 push_trailing(&mut buf, prev_line, &prev_hi, None);
 148                 // push lines between the previous and current span (if any)
 149                 for idx in prev_hi.line..(cur_lo.line - 1) {
 150                     if let Some(line) = fm.get_line(idx) {
 151                         buf.push_str(line);
 152                         buf.push('\n');
 153                     }
 154                 }
 155                 if let Some(cur_line) = fm.get_line(cur_lo.line - 1) {
 156                     buf.push_str(&cur_line[..cur_lo.col.to_usize()]);
 157                 }
 158             }
 159             buf.push_str(substitute);
 160             prev_hi = cm.lookup_char_pos(sp.hi);
 161             prev_line = fm.get_line(prev_hi.line - 1);
 162         }
 163         push_trailing(&mut buf, prev_line, &prev_hi, None);
 164         // remove trailing newline
 165         buf.pop();
 166         buf
 167     }
 168 }
 169
 170 /// Used as a return value to signify a fatal error occurred. (It is also
 171 /// used as the argument to panic at the moment, but that will eventually
 172 /// not be true.)
 173 #[derive(Copy, Clone, Debug)]
 174 #[must_use]
 175 pub struct FatalError;
 176
 177 impl fmt::Display for FatalError {
 178     fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
 179         write!(f, "parser fatal error")
 180     }
 181 }
 182
 183 impl error::Error for FatalError {
 184     fn description(&self) -> &str {
 185         "The parser has encountered a fatal error"
 186     }
 187 }
 188
 189 /// Signifies that the compiler died with an explicit call to `.bug`
 190 /// or `.span_bug` rather than a failed assertion, etc.
 191 #[derive(Copy, Clone, Debug)]
 192 pub struct ExplicitBug;
 193
 194 impl fmt::Display for ExplicitBug {
 195     fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
 196         write!(f, "parser internal bug")
 197     }
 198 }
 199
 200 impl error::Error for ExplicitBug {
 201     fn description(&self) -> &str {
 202         "The parser has encountered an internal bug"
 203     }
 204 }
 205
 206 pub use diagnostic::{Diagnostic, SubDiagnostic};
 207 pub use diagnostic_builder::DiagnosticBuilder;
 208
 209 /// A handler deals with errors; certain errors
 210 /// (fatal, bug, unimpl) may cause immediate exit,
 211 /// others log errors for later reporting.
 212 pub struct Handler {
 213     err_count: Cell<usize>,
 214     emitter: RefCell<Box<Emitter>>,
 215     pub can_emit_warnings: bool,
 216     treat_err_as_bug: bool,
 217     continue_after_error: Cell<bool>,
 218     delayed_span_bug: RefCell<Option<(MultiSpan, String)>>,
 219 }
 220
 221 impl Handler {
 222     pub fn with_tty_emitter(color_config: ColorConfig,
 223                             can_emit_warnings: bool,
 224                             treat_err_as_bug: bool,
 225                             cm: Option<Rc<CodeMapper>>)
 226                             -> Handler {
 227         let emitter = Box::new(EmitterWriter::stderr(color_config, cm));
 228         Handler::with_emitter(can_emit_warnings, treat_err_as_bug, emitter)
 229     }
 230
 231     pub fn with_emitter(can_emit_warnings: bool,
 232                         treat_err_as_bug: bool,
 233                         e: Box<Emitter>)
 234                         -> Handler {
 235         Handler {
 236             err_count: Cell::new(0),
 237             emitter: RefCell::new(e),
 238             can_emit_warnings: can_emit_warnings,
 239             treat_err_as_bug: treat_err_as_bug,
 240             continue_after_error: Cell::new(true),
 241             delayed_span_bug: RefCell::new(None),
 242         }
 243     }
 244
 245     pub fn set_continue_after_error(&self, continue_after_error: bool) {
 246         self.continue_after_error.set(continue_after_error);
 247     }
 248
 249     pub fn struct_dummy<'a>(&'a self) -> DiagnosticBuilder<'a> {
 250         DiagnosticBuilder::new(self, Level::Cancelled, "")
 251     }
 252
 253     pub fn struct_span_warn<'a, S: Into<MultiSpan>>(&'a self,
 254                                                     sp: S,
 255                                                     msg: &str)
 256                                                     -> DiagnosticBuilder<'a> {
 257         let mut result = DiagnosticBuilder::new(self, Level::Warning, msg);
 258         result.set_span(sp);
 259         if !self.can_emit_warnings {
 260             result.cancel();
 261         }
 262         result
 263     }
 264     pub fn struct_span_warn_with_code<'a, S: Into<MultiSpan>>(&'a self,
 265                                                               sp: S,
 266                                                               msg: &str,
 267                                                               code: &str)
 268                                                               -> DiagnosticBuilder<'a> {
 269         let mut result = DiagnosticBuilder::new(self, Level::Warning, msg);
 270         result.set_span(sp);
 271         result.code(code.to_owned());
 272         if !self.can_emit_warnings {
 273             result.cancel();
 274         }
 275         result
 276     }
 277     pub fn struct_warn<'a>(&'a self, msg: &str) -> DiagnosticBuilder<'a> {
 278         let mut result = DiagnosticBuilder::new(self, Level::Warning, msg);
 279         if !self.can_emit_warnings {
 280             result.cancel();
 281         }
 282         result
 283     }
 284     pub fn struct_span_err<'a, S: Into<MultiSpan>>(&'a self,
 285                                                    sp: S,
 286                                                    msg: &str)
 287                                                    -> DiagnosticBuilder<'a> {
 288         let mut result = DiagnosticBuilder::new(self, Level::Error, msg);
 289         result.set_span(sp);
 290         result
 291     }
 292     pub fn struct_span_err_with_code<'a, S: Into<MultiSpan>>(&'a self,
 293                                                              sp: S,
 294                                                              msg: &str,
 295                                                              code: &str)
 296                                                              -> DiagnosticBuilder<'a> {
 297         let mut result = DiagnosticBuilder::new(self, Level::Error, msg);
 298         result.set_span(sp);
 299         result.code(code.to_owned());
 300         result
 301     }
 302     pub fn struct_err<'a>(&'a self, msg: &str) -> DiagnosticBuilder<'a> {
 303         DiagnosticBuilder::new(self, Level::Error, msg)
 304     }
 305     pub fn struct_span_fatal<'a, S: Into<MultiSpan>>(&'a self,
 306                                                      sp: S,
 307                                                      msg: &str)
 308                                                      -> DiagnosticBuilder<'a> {
 309         let mut result = DiagnosticBuilder::new(self, Level::Fatal, msg);
 310         result.set_span(sp);
 311         result
 312     }
 313     pub fn struct_span_fatal_with_code<'a, S: Into<MultiSpan>>(&'a self,
 314                                                                sp: S,
 315                                                                msg: &str,
 316                                                                code: &str)
 317                                                                -> DiagnosticBuilder<'a> {
 318         let mut result = DiagnosticBuilder::new(self, Level::Fatal, msg);
 319         result.set_span(sp);
 320         result.code(code.to_owned());
 321         result
 322     }
 323     pub fn struct_fatal<'a>(&'a self, msg: &str) -> DiagnosticBuilder<'a> {
 324         DiagnosticBuilder::new(self, Level::Fatal, msg)
 325     }
 326
 327     pub fn cancel(&self, err: &mut DiagnosticBuilder) {
 328         err.cancel();
 329     }
 330
 331     fn panic_if_treat_err_as_bug(&self) {
 332         if self.treat_err_as_bug {
 333             panic!("encountered error with `-Z treat_err_as_bug");
 334         }
 335     }
 336
 337     pub fn span_fatal<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> FatalError {
 338         self.emit(&sp.into(), msg, Fatal);
 339         self.panic_if_treat_err_as_bug();
 340         return FatalError;
 341     }
 342     pub fn span_fatal_with_code<S: Into<MultiSpan>>(&self,
 343                                                     sp: S,
 344                                                     msg: &str,
 345                                                     code: &str)
 346                                                     -> FatalError {
 347         self.emit_with_code(&sp.into(), msg, code, Fatal);
 348         self.panic_if_treat_err_as_bug();
 349         return FatalError;
 350     }
 351     pub fn span_err<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
 352         self.emit(&sp.into(), msg, Error);
 353         self.panic_if_treat_err_as_bug();
 354     }
 355     pub fn mut_span_err<'a, S: Into<MultiSpan>>(&'a self,
 356                                                 sp: S,
 357                                                 msg: &str)
 358                                                 -> DiagnosticBuilder<'a> {
 359         let mut result = DiagnosticBuilder::new(self, Level::Error, msg);
 360         result.set_span(sp);
 361         result
 362     }
 363     pub fn span_err_with_code<S: Into<MultiSpan>>(&self, sp: S, msg: &str, code: &str) {
 364         self.emit_with_code(&sp.into(), msg, code, Error);
 365         self.panic_if_treat_err_as_bug();
 366     }
 367     pub fn span_warn<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
 368         self.emit(&sp.into(), msg, Warning);
 369     }
 370     pub fn span_warn_with_code<S: Into<MultiSpan>>(&self, sp: S, msg: &str, code: &str) {
 371         self.emit_with_code(&sp.into(), msg, code, Warning);
 372     }
 373     pub fn span_bug<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
 374         self.emit(&sp.into(), msg, Bug);
 375         panic!(ExplicitBug);
 376     }
 377     pub fn delay_span_bug<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
 378         let mut delayed = self.delayed_span_bug.borrow_mut();
 379         *delayed = Some((sp.into(), msg.to_string()));
 380     }
 381     pub fn span_bug_no_panic<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
 382         self.emit(&sp.into(), msg, Bug);
 383     }
 384     pub fn span_note_without_error<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
 385         self.emit(&sp.into(), msg, Note);
 386     }
 387     pub fn span_unimpl<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
 388         self.span_bug(sp, &format!("unimplemented {}", msg));
 389     }
 390     pub fn fatal(&self, msg: &str) -> FatalError {
 391         if self.treat_err_as_bug {
 392             self.bug(msg);
 393         }
 394         let mut db = DiagnosticBuilder::new(self, Fatal, msg);
 395         db.emit();
 396         FatalError
 397     }
 398     pub fn err(&self, msg: &str) {
 399         if self.treat_err_as_bug {
 400             self.bug(msg);
 401         }
 402         let mut db = DiagnosticBuilder::new(self, Error, msg);
 403         db.emit();
 404     }
 405     pub fn warn(&self, msg: &str) {
 406         let mut db = DiagnosticBuilder::new(self, Warning, msg);
 407         db.emit();
 408     }
 409     pub fn note_without_error(&self, msg: &str) {
 410         let mut db = DiagnosticBuilder::new(self, Note, msg);
 411         db.emit();
 412     }
 413     pub fn bug(&self, msg: &str) -> ! {
 414         let mut db = DiagnosticBuilder::new(self, Bug, msg);
 415         db.emit();
 416         panic!(ExplicitBug);
 417     }
 418     pub fn unimpl(&self, msg: &str) -> ! {
 419         self.bug(&format!("unimplemented {}", msg));
 420     }
 421
 422     pub fn bump_err_count(&self) {
 423         self.err_count.set(self.err_count.get() + 1);
 424     }
 425
 426     pub fn err_count(&self) -> usize {
 427         self.err_count.get()
 428     }
 429
 430     pub fn has_errors(&self) -> bool {
 431         self.err_count.get() > 0
 432     }
 433     pub fn abort_if_errors(&self) {
 434         let s;
 435         match self.err_count.get() {
 436             0 => {
 437                 let delayed_bug = self.delayed_span_bug.borrow();
 438                 match *delayed_bug {
 439                     Some((ref span, ref errmsg)) => {
 440                         self.span_bug(span.clone(), errmsg);
 441                     }
 442                     _ => {}
 443                 }
 444
 445                 return;
 446             }
 447             1 => s = "aborting due to previous error".to_string(),
 448             _ => {
 449                 s = format!("aborting due to {} previous errors", self.err_count.get());
 450             }
 451         }
 452
 453         panic!(self.fatal(&s));
 454     }
 455     pub fn emit(&self, msp: &MultiSpan, msg: &str, lvl: Level) {
 456         if lvl == Warning && !self.can_emit_warnings {
 457             return;
 458         }
 459         let mut db = DiagnosticBuilder::new(self, lvl, msg);
 460         db.set_span(msp.clone());
 461         db.emit();
 462         if !self.continue_after_error.get() {
 463             self.abort_if_errors();
 464         }
 465     }
 466     pub fn emit_with_code(&self, msp: &MultiSpan, msg: &str, code: &str, lvl: Level) {
 467         if lvl == Warning && !self.can_emit_warnings {
 468             return;
 469         }
 470         let mut db = DiagnosticBuilder::new_with_code(self, lvl, Some(code.to_owned()), msg);
 471         db.set_span(msp.clone());
 472         db.emit();
 473         if !self.continue_after_error.get() {
 474             self.abort_if_errors();
 475         }
 476     }
 477 }
 478
 479
 480 #[derive(Copy, PartialEq, Clone, Debug)]
 481 pub enum Level {
 482     Bug,
 483     Fatal,
 484     // An error which while not immediately fatal, should stop the compiler
 485     // progressing beyond the current phase.
 486     PhaseFatal,
 487     Error,
 488     Warning,
 489     Note,
 490     Help,
 491     Cancelled,
 492 }
 493
 494 impl fmt::Display for Level {
 495     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 496         self.to_str().fmt(f)
 497     }
 498 }
 499
 500 impl Level {
 501     pub fn color(self) -> term::color::Color {
 502         match self {
 503             Bug | Fatal | PhaseFatal | Error => term::color::BRIGHT_RED,
 504             Warning => {
 505                 if cfg!(windows) {
 506                     term::color::BRIGHT_YELLOW
 507                 } else {
 508                     term::color::YELLOW
 509                 }
 510             }
 511             Note => term::color::BRIGHT_GREEN,
 512             Help => term::color::BRIGHT_CYAN,
 513             Cancelled => unreachable!(),
 514         }
 515     }
 516
 517     pub fn to_str(self) -> &'static str {
 518         match self {
 519             Bug => "error: internal compiler error",
 520             Fatal | PhaseFatal | Error => "error",
 521             Warning => "warning",
 522             Note => "note",
 523             Help => "help",
 524             Cancelled => panic!("Shouldn't call on cancelled error"),
 525         }
 526     }
 527 }
 528
 529 pub fn expect<T, M>(diag: &Handler, opt: Option<T>, msg: M) -> T
 530     where M: FnOnce() -> String
 531 {
 532     match opt {
 533         Some(t) => t,
 534         None => diag.bug(&msg()),
 535     }
 536 }