compiler/rustc_errors/src/lib.rs

   1 //! Diagnostics creation and emission for `rustc`.
   2 //!
   3 //! This module contains the code for creating and emitting diagnostics.
   4
   5 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
   6 #![feature(crate_visibility_modifier)]
   7 #![feature(backtrace)]
   8 #![feature(nll)]
   9
  10 #[macro_use]
  11 extern crate rustc_macros;
  12
  13 pub use emitter::ColorConfig;
  14
  15 use tracing::debug;
  16 use Level::*;
  17
  18 use emitter::{is_case_difference, Emitter, EmitterWriter};
  19 use registry::Registry;
  20 use rustc_data_structures::fx::{FxHashSet, FxIndexMap};
  21 use rustc_data_structures::stable_hasher::StableHasher;
  22 use rustc_data_structures::sync::{self, Lock, Lrc};
  23 use rustc_data_structures::AtomicRef;
  24 use rustc_span::source_map::SourceMap;
  25 use rustc_span::{Loc, MultiSpan, Span};
  26
  27 use std::borrow::Cow;
  28 use std::panic;
  29 use std::path::Path;
  30 use std::{error, fmt};
  31
  32 use termcolor::{Color, ColorSpec};
  33
  34 pub mod annotate_snippet_emitter_writer;
  35 mod diagnostic;
  36 mod diagnostic_builder;
  37 pub mod emitter;
  38 pub mod json;
  39 mod lock;
  40 pub mod registry;
  41 mod snippet;
  42 mod styled_buffer;
  43 pub use snippet::Style;
  44
  45 pub type PResult<'a, T> = Result<T, DiagnosticBuilder<'a>>;
  46
  47 // `PResult` is used a lot. Make sure it doesn't unintentionally get bigger.
  48 // (See also the comment on `DiagnosticBuilderInner`.)
  49 #[cfg(target_arch = "x86_64")]
  50 rustc_data_structures::static_assert_size!(PResult<'_, bool>, 16);
  51
  52 /// Indicates the confidence in the correctness of a suggestion.
  53 ///
  54 /// All suggestions are marked with an `Applicability`. Tools use the applicability of a suggestion
  55 /// to determine whether it should be automatically applied or if the user should be consulted
  56 /// before applying the suggestion.
  57 #[derive(Copy, Clone, Debug, PartialEq, Hash, Encodable, Decodable)]
  58 pub enum Applicability {
  59     /// The suggestion is definitely what the user intended. This suggestion should be
  60     /// automatically applied.
  61     MachineApplicable,
  62
  63     /// The suggestion may be what the user intended, but it is uncertain. The suggestion should
  64     /// result in valid Rust code if it is applied.
  65     MaybeIncorrect,
  66
  67     /// The suggestion contains placeholders like `(...)` or `{ /* fields */ }`. The suggestion
  68     /// cannot be applied automatically because it will not result in valid Rust code. The user
  69     /// will need to fill in the placeholders.
  70     HasPlaceholders,
  71
  72     /// The applicability of the suggestion is unknown.
  73     Unspecified,
  74 }
  75
  76 #[derive(Debug, PartialEq, Eq, Clone, Copy, Hash, Encodable, Decodable)]
  77 pub enum SuggestionStyle {
  78     /// Hide the suggested code when displaying this suggestion inline.
  79     HideCodeInline,
  80     /// Always hide the suggested code but display the message.
  81     HideCodeAlways,
  82     /// Do not display this suggestion in the cli output, it is only meant for tools.
  83     CompletelyHidden,
  84     /// Always show the suggested code.
  85     /// This will *not* show the code if the suggestion is inline *and* the suggested code is
  86     /// empty.
  87     ShowCode,
  88     /// Always show the suggested code independently.
  89     ShowAlways,
  90 }
  91
  92 impl SuggestionStyle {
  93     fn hide_inline(&self) -> bool {
  94         match *self {
  95             SuggestionStyle::ShowCode => false,
  96             _ => true,
  97         }
  98     }
  99 }
 100
 101 #[derive(Clone, Debug, PartialEq, Hash, Encodable, Decodable)]
 102 pub struct CodeSuggestion {
 103     /// Each substitute can have multiple variants due to multiple
 104     /// applicable suggestions
 105     ///
 106     /// `foo.bar` might be replaced with `a.b` or `x.y` by replacing
 107     /// `foo` and `bar` on their own:
 108     ///
 109     /// ```
 110     /// vec![
 111     ///     Substitution { parts: vec![(0..3, "a"), (4..7, "b")] },
 112     ///     Substitution { parts: vec![(0..3, "x"), (4..7, "y")] },
 113     /// ]
 114     /// ```
 115     ///
 116     /// or by replacing the entire span:
 117     ///
 118     /// ```
 119     /// vec![
 120     ///     Substitution { parts: vec![(0..7, "a.b")] },
 121     ///     Substitution { parts: vec![(0..7, "x.y")] },
 122     /// ]
 123     /// ```
 124     pub substitutions: Vec<Substitution>,
 125     pub msg: String,
 126     /// Visual representation of this suggestion.
 127     pub style: SuggestionStyle,
 128     /// Whether or not the suggestion is approximate
 129     ///
 130     /// Sometimes we may show suggestions with placeholders,
 131     /// which are useful for users but not useful for
 132     /// tools like rustfix
 133     pub applicability: Applicability,
 134 }
 135
 136 #[derive(Clone, Debug, PartialEq, Hash, Encodable, Decodable)]
 137 /// See the docs on `CodeSuggestion::substitutions`
 138 pub struct Substitution {
 139     pub parts: Vec<SubstitutionPart>,
 140 }
 141
 142 #[derive(Clone, Debug, PartialEq, Hash, Encodable, Decodable)]
 143 pub struct SubstitutionPart {
 144     pub span: Span,
 145     pub snippet: String,
 146 }
 147
 148 impl CodeSuggestion {
 149     /// Returns the assembled code suggestions, whether they should be shown with an underline
 150     /// and whether the substitution only differs in capitalization.
 151     pub fn splice_lines(&self, sm: &SourceMap) -> Vec<(String, Vec<SubstitutionPart>, bool)> {
 152         use rustc_span::{CharPos, Pos};
 153
 154         fn push_trailing(
 155             buf: &mut String,
 156             line_opt: Option<&Cow<'_, str>>,
 157             lo: &Loc,
 158             hi_opt: Option<&Loc>,
 159         ) {
 160             let (lo, hi_opt) = (lo.col.to_usize(), hi_opt.map(|hi| hi.col.to_usize()));
 161             if let Some(line) = line_opt {
 162                 if let Some(lo) = line.char_indices().map(|(i, _)| i).nth(lo) {
 163                     let hi_opt = hi_opt.and_then(|hi| line.char_indices().map(|(i, _)| i).nth(hi));
 164                     match hi_opt {
 165                         Some(hi) if hi > lo => buf.push_str(&line[lo..hi]),
 166                         Some(_) => (),
 167                         None => buf.push_str(&line[lo..]),
 168                     }
 169                 }
 170                 if hi_opt.is_none() {
 171                     buf.push('\n');
 172                 }
 173             }
 174         }
 175
 176         assert!(!self.substitutions.is_empty());
 177
 178         self.substitutions
 179             .iter()
 180             .filter(|subst| {
 181                 // Suggestions coming from macros can have malformed spans. This is a heavy
 182                 // handed approach to avoid ICEs by ignoring the suggestion outright.
 183                 let invalid = subst.parts.iter().any(|item| sm.is_valid_span(item.span).is_err());
 184                 if invalid {
 185                     debug!("splice_lines: suggestion contains an invalid span: {:?}", subst);
 186                 }
 187                 !invalid
 188             })
 189             .cloned()
 190             .filter_map(|mut substitution| {
 191                 // Assumption: all spans are in the same file, and all spans
 192                 // are disjoint. Sort in ascending order.
 193                 substitution.parts.sort_by_key(|part| part.span.lo());
 194
 195                 // Find the bounding span.
 196                 let lo = substitution.parts.iter().map(|part| part.span.lo()).min()?;
 197                 let hi = substitution.parts.iter().map(|part| part.span.hi()).max()?;
 198                 let bounding_span = Span::with_root_ctxt(lo, hi);
 199                 // The different spans might belong to different contexts, if so ignore suggestion.
 200                 let lines = sm.span_to_lines(bounding_span).ok()?;
 201                 assert!(!lines.lines.is_empty() || bounding_span.is_dummy());
 202
 203                 // We can't splice anything if the source is unavailable.
 204                 if !sm.ensure_source_file_source_present(lines.file.clone()) {
 205                     return None;
 206                 }
 207
 208                 // To build up the result, we do this for each span:
 209                 // - push the line segment trailing the previous span
 210                 //   (at the beginning a "phantom" span pointing at the start of the line)
 211                 // - push lines between the previous and current span (if any)
 212                 // - if the previous and current span are not on the same line
 213                 //   push the line segment leading up to the current span
 214                 // - splice in the span substitution
 215                 //
 216                 // Finally push the trailing line segment of the last span
 217                 let sf = &lines.file;
 218                 let mut prev_hi = sm.lookup_char_pos(bounding_span.lo());
 219                 prev_hi.col = CharPos::from_usize(0);
 220                 let mut prev_line =
 221                     lines.lines.get(0).and_then(|line0| sf.get_line(line0.line_index));
 222                 let mut buf = String::new();
 223
 224                 for part in &substitution.parts {
 225                     let cur_lo = sm.lookup_char_pos(part.span.lo());
 226                     if prev_hi.line == cur_lo.line {
 227                         push_trailing(&mut buf, prev_line.as_ref(), &prev_hi, Some(&cur_lo));
 228                     } else {
 229                         push_trailing(&mut buf, prev_line.as_ref(), &prev_hi, None);
 230                         // push lines between the previous and current span (if any)
 231                         for idx in prev_hi.line..(cur_lo.line - 1) {
 232                             if let Some(line) = sf.get_line(idx) {
 233                                 buf.push_str(line.as_ref());
 234                                 buf.push('\n');
 235                             }
 236                         }
 237                         if let Some(cur_line) = sf.get_line(cur_lo.line - 1) {
 238                             let end = match cur_line.char_indices().nth(cur_lo.col.to_usize()) {
 239                                 Some((i, _)) => i,
 240                                 None => cur_line.len(),
 241                             };
 242                             buf.push_str(&cur_line[..end]);
 243                         }
 244                     }
 245                     buf.push_str(&part.snippet);
 246                     prev_hi = sm.lookup_char_pos(part.span.hi());
 247                     prev_line = sf.get_line(prev_hi.line - 1);
 248                 }
 249                 let only_capitalization = is_case_difference(sm, &buf, bounding_span);
 250                 // if the replacement already ends with a newline, don't print the next line
 251                 if !buf.ends_with('\n') {
 252                     push_trailing(&mut buf, prev_line.as_ref(), &prev_hi, None);
 253                 }
 254                 // remove trailing newlines
 255                 while buf.ends_with('\n') {
 256                     buf.pop();
 257                 }
 258                 Some((buf, substitution.parts, only_capitalization))
 259             })
 260             .collect()
 261     }
 262 }
 263
 264 pub use rustc_span::fatal_error::{FatalError, FatalErrorMarker};
 265
 266 /// Signifies that the compiler died with an explicit call to `.bug`
 267 /// or `.span_bug` rather than a failed assertion, etc.
 268 #[derive(Copy, Clone, Debug)]
 269 pub struct ExplicitBug;
 270
 271 impl fmt::Display for ExplicitBug {
 272     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 273         write!(f, "parser internal bug")
 274     }
 275 }
 276
 277 impl error::Error for ExplicitBug {}
 278
 279 pub use diagnostic::{Diagnostic, DiagnosticId, DiagnosticStyledString, SubDiagnostic};
 280 pub use diagnostic_builder::DiagnosticBuilder;
 281
 282 /// A handler deals with errors and other compiler output.
 283 /// Certain errors (fatal, bug, unimpl) may cause immediate exit,
 284 /// others log errors for later reporting.
 285 pub struct Handler {
 286     flags: HandlerFlags,
 287     inner: Lock<HandlerInner>,
 288 }
 289
 290 /// This inner struct exists to keep it all behind a single lock;
 291 /// this is done to prevent possible deadlocks in a multi-threaded compiler,
 292 /// as well as inconsistent state observation.
 293 struct HandlerInner {
 294     flags: HandlerFlags,
 295     /// The number of errors that have been emitted, including duplicates.
 296     ///
 297     /// This is not necessarily the count that's reported to the user once
 298     /// compilation ends.
 299     err_count: usize,
 300     warn_count: usize,
 301     deduplicated_err_count: usize,
 302     emitter: Box<dyn Emitter + sync::Send>,
 303     delayed_span_bugs: Vec<Diagnostic>,
 304     delayed_good_path_bugs: Vec<Diagnostic>,
 305
 306     /// This set contains the `DiagnosticId` of all emitted diagnostics to avoid
 307     /// emitting the same diagnostic with extended help (`--teach`) twice, which
 308     /// would be uneccessary repetition.
 309     taught_diagnostics: FxHashSet<DiagnosticId>,
 310
 311     /// Used to suggest rustc --explain <error code>
 312     emitted_diagnostic_codes: FxHashSet<DiagnosticId>,
 313
 314     /// This set contains a hash of every diagnostic that has been emitted by
 315     /// this handler. These hashes is used to avoid emitting the same error
 316     /// twice.
 317     emitted_diagnostics: FxHashSet<u128>,
 318
 319     /// Stashed diagnostics emitted in one stage of the compiler that may be
 320     /// stolen by other stages (e.g. to improve them and add more information).
 321     /// The stashed diagnostics count towards the total error count.
 322     /// When `.abort_if_errors()` is called, these are also emitted.
 323     stashed_diagnostics: FxIndexMap<(Span, StashKey), Diagnostic>,
 324
 325     /// The warning count, used for a recap upon finishing
 326     deduplicated_warn_count: usize,
 327 }
 328
 329 /// A key denoting where from a diagnostic was stashed.
 330 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
 331 pub enum StashKey {
 332     ItemNoType,
 333 }
 334
 335 fn default_track_diagnostic(_: &Diagnostic) {}
 336
 337 pub static TRACK_DIAGNOSTICS: AtomicRef<fn(&Diagnostic)> =
 338     AtomicRef::new(&(default_track_diagnostic as fn(&_)));
 339
 340 #[derive(Copy, Clone, Default)]
 341 pub struct HandlerFlags {
 342     /// If false, warning-level lints are suppressed.
 343     /// (rustc: see `--allow warnings` and `--cap-lints`)
 344     pub can_emit_warnings: bool,
 345     /// If true, error-level diagnostics are upgraded to bug-level.
 346     /// (rustc: see `-Z treat-err-as-bug`)
 347     pub treat_err_as_bug: Option<usize>,
 348     /// If true, immediately emit diagnostics that would otherwise be buffered.
 349     /// (rustc: see `-Z dont-buffer-diagnostics` and `-Z treat-err-as-bug`)
 350     pub dont_buffer_diagnostics: bool,
 351     /// If true, immediately print bugs registered with `delay_span_bug`.
 352     /// (rustc: see `-Z report-delayed-bugs`)
 353     pub report_delayed_bugs: bool,
 354     /// Show macro backtraces.
 355     /// (rustc: see `-Z macro-backtrace`)
 356     pub macro_backtrace: bool,
 357     /// If true, identical diagnostics are reported only once.
 358     pub deduplicate_diagnostics: bool,
 359 }
 360
 361 impl Drop for HandlerInner {
 362     fn drop(&mut self) {
 363         self.emit_stashed_diagnostics();
 364
 365         if !self.has_errors() {
 366             let bugs = std::mem::replace(&mut self.delayed_span_bugs, Vec::new());
 367             self.flush_delayed(bugs, "no errors encountered even though `delay_span_bug` issued");
 368         }
 369
 370         if !self.has_any_message() {
 371             let bugs = std::mem::replace(&mut self.delayed_good_path_bugs, Vec::new());
 372             self.flush_delayed(
 373                 bugs,
 374                 "no warnings or errors encountered even though `delayed_good_path_bugs` issued",
 375             );
 376         }
 377     }
 378 }
 379
 380 impl Handler {
 381     pub fn with_tty_emitter(
 382         color_config: ColorConfig,
 383         can_emit_warnings: bool,
 384         treat_err_as_bug: Option<usize>,
 385         sm: Option<Lrc<SourceMap>>,
 386     ) -> Self {
 387         Self::with_tty_emitter_and_flags(
 388             color_config,
 389             sm,
 390             HandlerFlags { can_emit_warnings, treat_err_as_bug, ..Default::default() },
 391         )
 392     }
 393
 394     pub fn with_tty_emitter_and_flags(
 395         color_config: ColorConfig,
 396         sm: Option<Lrc<SourceMap>>,
 397         flags: HandlerFlags,
 398     ) -> Self {
 399         let emitter = Box::new(EmitterWriter::stderr(
 400             color_config,
 401             sm,
 402             false,
 403             false,
 404             None,
 405             flags.macro_backtrace,
 406         ));
 407         Self::with_emitter_and_flags(emitter, flags)
 408     }
 409
 410     pub fn with_emitter(
 411         can_emit_warnings: bool,
 412         treat_err_as_bug: Option<usize>,
 413         emitter: Box<dyn Emitter + sync::Send>,
 414     ) -> Self {
 415         Handler::with_emitter_and_flags(
 416             emitter,
 417             HandlerFlags { can_emit_warnings, treat_err_as_bug, ..Default::default() },
 418         )
 419     }
 420
 421     pub fn with_emitter_and_flags(
 422         emitter: Box<dyn Emitter + sync::Send>,
 423         flags: HandlerFlags,
 424     ) -> Self {
 425         Self {
 426             flags,
 427             inner: Lock::new(HandlerInner {
 428                 flags,
 429                 err_count: 0,
 430                 warn_count: 0,
 431                 deduplicated_err_count: 0,
 432                 deduplicated_warn_count: 0,
 433                 emitter,
 434                 delayed_span_bugs: Vec::new(),
 435                 delayed_good_path_bugs: Vec::new(),
 436                 taught_diagnostics: Default::default(),
 437                 emitted_diagnostic_codes: Default::default(),
 438                 emitted_diagnostics: Default::default(),
 439                 stashed_diagnostics: Default::default(),
 440             }),
 441         }
 442     }
 443
 444     // This is here to not allow mutation of flags;
 445     // as of this writing it's only used in tests in librustc_middle.
 446     pub fn can_emit_warnings(&self) -> bool {
 447         self.flags.can_emit_warnings
 448     }
 449
 450     /// Resets the diagnostic error count as well as the cached emitted diagnostics.
 451     ///
 452     /// NOTE: *do not* call this function from rustc. It is only meant to be called from external
 453     /// tools that want to reuse a `Parser` cleaning the previously emitted diagnostics as well as
 454     /// the overall count of emitted error diagnostics.
 455     pub fn reset_err_count(&self) {
 456         let mut inner = self.inner.borrow_mut();
 457         inner.err_count = 0;
 458         inner.warn_count = 0;
 459         inner.deduplicated_err_count = 0;
 460         inner.deduplicated_warn_count = 0;
 461
 462         // actually free the underlying memory (which `clear` would not do)
 463         inner.delayed_span_bugs = Default::default();
 464         inner.delayed_good_path_bugs = Default::default();
 465         inner.taught_diagnostics = Default::default();
 466         inner.emitted_diagnostic_codes = Default::default();
 467         inner.emitted_diagnostics = Default::default();
 468         inner.stashed_diagnostics = Default::default();
 469     }
 470
 471     /// Stash a given diagnostic with the given `Span` and `StashKey` as the key for later stealing.
 472     pub fn stash_diagnostic(&self, span: Span, key: StashKey, diag: Diagnostic) {
 473         let mut inner = self.inner.borrow_mut();
 474         // FIXME(Centril, #69537): Consider reintroducing panic on overwriting a stashed diagnostic
 475         // if/when we have a more robust macro-friendly replacement for `(span, key)` as a key.
 476         // See the PR for a discussion.
 477         inner.stashed_diagnostics.insert((span, key), diag);
 478     }
 479
 480     /// Steal a previously stashed diagnostic with the given `Span` and `StashKey` as the key.
 481     pub fn steal_diagnostic(&self, span: Span, key: StashKey) -> Option<DiagnosticBuilder<'_>> {
 482         self.inner
 483             .borrow_mut()
 484             .stashed_diagnostics
 485             .remove(&(span, key))
 486             .map(|diag| DiagnosticBuilder::new_diagnostic(self, diag))
 487     }
 488
 489     /// Emit all stashed diagnostics.
 490     pub fn emit_stashed_diagnostics(&self) {
 491         self.inner.borrow_mut().emit_stashed_diagnostics();
 492     }
 493
 494     /// Construct a dummy builder with `Level::Cancelled`.
 495     ///
 496     /// Using this will neither report anything to the user (e.g. a warning),
 497     /// nor will compilation cancel as a result.
 498     pub fn struct_dummy(&self) -> DiagnosticBuilder<'_> {
 499         DiagnosticBuilder::new(self, Level::Cancelled, "")
 500     }
 501
 502     /// Construct a builder at the `Warning` level at the given `span` and with the `msg`.
 503     pub fn struct_span_warn(&self, span: impl Into<MultiSpan>, msg: &str) -> DiagnosticBuilder<'_> {
 504         let mut result = self.struct_warn(msg);
 505         result.set_span(span);
 506         result
 507     }
 508
 509     /// Construct a builder at the `Warning` level at the given `span` and with the `msg`.
 510     /// Also include a code.
 511     pub fn struct_span_warn_with_code(
 512         &self,
 513         span: impl Into<MultiSpan>,
 514         msg: &str,
 515         code: DiagnosticId,
 516     ) -> DiagnosticBuilder<'_> {
 517         let mut result = self.struct_span_warn(span, msg);
 518         result.code(code);
 519         result
 520     }
 521
 522     /// Construct a builder at the `Warning` level with the `msg`.
 523     pub fn struct_warn(&self, msg: &str) -> DiagnosticBuilder<'_> {
 524         let mut result = DiagnosticBuilder::new(self, Level::Warning, msg);
 525         if !self.flags.can_emit_warnings {
 526             result.cancel();
 527         }
 528         result
 529     }
 530
 531     /// Construct a builder at the `Error` level at the given `span` and with the `msg`.
 532     pub fn struct_span_err(&self, span: impl Into<MultiSpan>, msg: &str) -> DiagnosticBuilder<'_> {
 533         let mut result = self.struct_err(msg);
 534         result.set_span(span);
 535         result
 536     }
 537
 538     /// Construct a builder at the `Error` level at the given `span`, with the `msg`, and `code`.
 539     pub fn struct_span_err_with_code(
 540         &self,
 541         span: impl Into<MultiSpan>,
 542         msg: &str,
 543         code: DiagnosticId,
 544     ) -> DiagnosticBuilder<'_> {
 545         let mut result = self.struct_span_err(span, msg);
 546         result.code(code);
 547         result
 548     }
 549
 550     /// Construct a builder at the `Error` level with the `msg`.
 551     // FIXME: This method should be removed (every error should have an associated error code).
 552     pub fn struct_err(&self, msg: &str) -> DiagnosticBuilder<'_> {
 553         DiagnosticBuilder::new(self, Level::Error, msg)
 554     }
 555
 556     /// Construct a builder at the `Error` level with the `msg` and the `code`.
 557     pub fn struct_err_with_code(&self, msg: &str, code: DiagnosticId) -> DiagnosticBuilder<'_> {
 558         let mut result = self.struct_err(msg);
 559         result.code(code);
 560         result
 561     }
 562
 563     /// Construct a builder at the `Fatal` level at the given `span` and with the `msg`.
 564     pub fn struct_span_fatal(
 565         &self,
 566         span: impl Into<MultiSpan>,
 567         msg: &str,
 568     ) -> DiagnosticBuilder<'_> {
 569         let mut result = self.struct_fatal(msg);
 570         result.set_span(span);
 571         result
 572     }
 573
 574     /// Construct a builder at the `Fatal` level at the given `span`, with the `msg`, and `code`.
 575     pub fn struct_span_fatal_with_code(
 576         &self,
 577         span: impl Into<MultiSpan>,
 578         msg: &str,
 579         code: DiagnosticId,
 580     ) -> DiagnosticBuilder<'_> {
 581         let mut result = self.struct_span_fatal(span, msg);
 582         result.code(code);
 583         result
 584     }
 585
 586     /// Construct a builder at the `Error` level with the `msg`.
 587     pub fn struct_fatal(&self, msg: &str) -> DiagnosticBuilder<'_> {
 588         DiagnosticBuilder::new(self, Level::Fatal, msg)
 589     }
 590
 591     /// Construct a builder at the `Help` level with the `msg`.
 592     pub fn struct_help(&self, msg: &str) -> DiagnosticBuilder<'_> {
 593         DiagnosticBuilder::new(self, Level::Help, msg)
 594     }
 595
 596     /// Construct a builder at the `Note` level with the `msg`.
 597     pub fn struct_note_without_error(&self, msg: &str) -> DiagnosticBuilder<'_> {
 598         DiagnosticBuilder::new(self, Level::Note, msg)
 599     }
 600
 601     pub fn span_fatal(&self, span: impl Into<MultiSpan>, msg: &str) -> FatalError {
 602         self.emit_diag_at_span(Diagnostic::new(Fatal, msg), span);
 603         FatalError
 604     }
 605
 606     pub fn span_fatal_with_code(
 607         &self,
 608         span: impl Into<MultiSpan>,
 609         msg: &str,
 610         code: DiagnosticId,
 611     ) -> FatalError {
 612         self.emit_diag_at_span(Diagnostic::new_with_code(Fatal, Some(code), msg), span);
 613         FatalError
 614     }
 615
 616     pub fn span_err(&self, span: impl Into<MultiSpan>, msg: &str) {
 617         self.emit_diag_at_span(Diagnostic::new(Error, msg), span);
 618     }
 619
 620     pub fn span_err_with_code(&self, span: impl Into<MultiSpan>, msg: &str, code: DiagnosticId) {
 621         self.emit_diag_at_span(Diagnostic::new_with_code(Error, Some(code), msg), span);
 622     }
 623
 624     pub fn span_warn(&self, span: impl Into<MultiSpan>, msg: &str) {
 625         self.emit_diag_at_span(Diagnostic::new(Warning, msg), span);
 626     }
 627
 628     pub fn span_warn_with_code(&self, span: impl Into<MultiSpan>, msg: &str, code: DiagnosticId) {
 629         self.emit_diag_at_span(Diagnostic::new_with_code(Warning, Some(code), msg), span);
 630     }
 631
 632     pub fn span_bug(&self, span: impl Into<MultiSpan>, msg: &str) -> ! {
 633         self.inner.borrow_mut().span_bug(span, msg)
 634     }
 635
 636     #[track_caller]
 637     pub fn delay_span_bug(&self, span: impl Into<MultiSpan>, msg: &str) {
 638         self.inner.borrow_mut().delay_span_bug(span, msg)
 639     }
 640
 641     pub fn delay_good_path_bug(&self, msg: &str) {
 642         self.inner.borrow_mut().delay_good_path_bug(msg)
 643     }
 644
 645     pub fn span_bug_no_panic(&self, span: impl Into<MultiSpan>, msg: &str) {
 646         self.emit_diag_at_span(Diagnostic::new(Bug, msg), span);
 647     }
 648
 649     pub fn span_note_without_error(&self, span: impl Into<MultiSpan>, msg: &str) {
 650         self.emit_diag_at_span(Diagnostic::new(Note, msg), span);
 651     }
 652
 653     pub fn span_note_diag(&self, span: Span, msg: &str) -> DiagnosticBuilder<'_> {
 654         let mut db = DiagnosticBuilder::new(self, Note, msg);
 655         db.set_span(span);
 656         db
 657     }
 658
 659     pub fn failure(&self, msg: &str) {
 660         self.inner.borrow_mut().failure(msg);
 661     }
 662
 663     pub fn fatal(&self, msg: &str) -> FatalError {
 664         self.inner.borrow_mut().fatal(msg)
 665     }
 666
 667     pub fn err(&self, msg: &str) {
 668         self.inner.borrow_mut().err(msg);
 669     }
 670
 671     pub fn warn(&self, msg: &str) {
 672         let mut db = DiagnosticBuilder::new(self, Warning, msg);
 673         db.emit();
 674     }
 675
 676     pub fn note_without_error(&self, msg: &str) {
 677         DiagnosticBuilder::new(self, Note, msg).emit();
 678     }
 679
 680     pub fn bug(&self, msg: &str) -> ! {
 681         self.inner.borrow_mut().bug(msg)
 682     }
 683
 684     pub fn err_count(&self) -> usize {
 685         self.inner.borrow().err_count()
 686     }
 687
 688     pub fn has_errors(&self) -> bool {
 689         self.inner.borrow().has_errors()
 690     }
 691     pub fn has_errors_or_delayed_span_bugs(&self) -> bool {
 692         self.inner.borrow().has_errors_or_delayed_span_bugs()
 693     }
 694
 695     pub fn print_error_count(&self, registry: &Registry) {
 696         self.inner.borrow_mut().print_error_count(registry)
 697     }
 698
 699     pub fn abort_if_errors(&self) {
 700         self.inner.borrow_mut().abort_if_errors()
 701     }
 702
 703     /// `true` if we haven't taught a diagnostic with this code already.
 704     /// The caller must then teach the user about such a diagnostic.
 705     ///
 706     /// Used to suppress emitting the same error multiple times with extended explanation when
 707     /// calling `-Zteach`.
 708     pub fn must_teach(&self, code: &DiagnosticId) -> bool {
 709         self.inner.borrow_mut().must_teach(code)
 710     }
 711
 712     pub fn force_print_diagnostic(&self, db: Diagnostic) {
 713         self.inner.borrow_mut().force_print_diagnostic(db)
 714     }
 715
 716     pub fn emit_diagnostic(&self, diagnostic: &Diagnostic) {
 717         self.inner.borrow_mut().emit_diagnostic(diagnostic)
 718     }
 719
 720     fn emit_diag_at_span(&self, mut diag: Diagnostic, sp: impl Into<MultiSpan>) {
 721         let mut inner = self.inner.borrow_mut();
 722         inner.emit_diagnostic(diag.set_span(sp));
 723     }
 724
 725     pub fn emit_artifact_notification(&self, path: &Path, artifact_type: &str) {
 726         self.inner.borrow_mut().emit_artifact_notification(path, artifact_type)
 727     }
 728
 729     pub fn delay_as_bug(&self, diagnostic: Diagnostic) {
 730         self.inner.borrow_mut().delay_as_bug(diagnostic)
 731     }
 732 }
 733
 734 impl HandlerInner {
 735     fn must_teach(&mut self, code: &DiagnosticId) -> bool {
 736         self.taught_diagnostics.insert(code.clone())
 737     }
 738
 739     fn force_print_diagnostic(&mut self, db: Diagnostic) {
 740         self.emitter.emit_diagnostic(&db);
 741     }
 742
 743     /// Emit all stashed diagnostics.
 744     fn emit_stashed_diagnostics(&mut self) {
 745         let diags = self.stashed_diagnostics.drain(..).map(|x| x.1).collect::<Vec<_>>();
 746         diags.iter().for_each(|diag| self.emit_diagnostic(diag));
 747     }
 748
 749     fn emit_diagnostic(&mut self, diagnostic: &Diagnostic) {
 750         if diagnostic.cancelled() {
 751             return;
 752         }
 753
 754         if diagnostic.level == Warning && !self.flags.can_emit_warnings {
 755             return;
 756         }
 757
 758         (*TRACK_DIAGNOSTICS)(diagnostic);
 759
 760         if let Some(ref code) = diagnostic.code {
 761             self.emitted_diagnostic_codes.insert(code.clone());
 762         }
 763
 764         let already_emitted = |this: &mut Self| {
 765             use std::hash::Hash;
 766             let mut hasher = StableHasher::new();
 767             diagnostic.hash(&mut hasher);
 768             let diagnostic_hash = hasher.finish();
 769             !this.emitted_diagnostics.insert(diagnostic_hash)
 770         };
 771
 772         // Only emit the diagnostic if we've been asked to deduplicate and
 773         // haven't already emitted an equivalent diagnostic.
 774         if !(self.flags.deduplicate_diagnostics && already_emitted(self)) {
 775             self.emitter.emit_diagnostic(diagnostic);
 776             if diagnostic.is_error() {
 777                 self.deduplicated_err_count += 1;
 778             } else if diagnostic.level == Warning {
 779                 self.deduplicated_warn_count += 1;
 780             }
 781         }
 782         if diagnostic.is_error() {
 783             self.bump_err_count();
 784         } else {
 785             self.bump_warn_count();
 786         }
 787     }
 788
 789     fn emit_artifact_notification(&mut self, path: &Path, artifact_type: &str) {
 790         self.emitter.emit_artifact_notification(path, artifact_type);
 791     }
 792
 793     fn treat_err_as_bug(&self) -> bool {
 794         self.flags.treat_err_as_bug.map(|c| self.err_count() >= c).unwrap_or(false)
 795     }
 796
 797     fn print_error_count(&mut self, registry: &Registry) {
 798         self.emit_stashed_diagnostics();
 799
 800         let warnings = match self.deduplicated_warn_count {
 801             0 => String::new(),
 802             1 => "1 warning emitted".to_string(),
 803             count => format!("{} warnings emitted", count),
 804         };
 805         let errors = match self.deduplicated_err_count {
 806             0 => String::new(),
 807             1 => "aborting due to previous error".to_string(),
 808             count => format!("aborting due to {} previous errors", count),
 809         };
 810         if self.treat_err_as_bug() {
 811             return;
 812         }
 813
 814         match (errors.len(), warnings.len()) {
 815             (0, 0) => return,
 816             (0, _) => self.emit_diagnostic(&Diagnostic::new(Level::Warning, &warnings)),
 817             (_, 0) => {
 818                 let _ = self.fatal(&errors);
 819             }
 820             (_, _) => {
 821                 let _ = self.fatal(&format!("{}; {}", &errors, &warnings));
 822             }
 823         }
 824
 825         let can_show_explain = self.emitter.should_show_explain();
 826         let are_there_diagnostics = !self.emitted_diagnostic_codes.is_empty();
 827         if can_show_explain && are_there_diagnostics {
 828             let mut error_codes = self
 829                 .emitted_diagnostic_codes
 830                 .iter()
 831                 .filter_map(|x| match &x {
 832                     DiagnosticId::Error(s) => {
 833                         if let Ok(Some(_explanation)) = registry.try_find_description(s) {
 834                             Some(s.clone())
 835                         } else {
 836                             None
 837                         }
 838                     }
 839                     _ => None,
 840                 })
 841                 .collect::<Vec<_>>();
 842             if !error_codes.is_empty() {
 843                 error_codes.sort();
 844                 if error_codes.len() > 1 {
 845                     let limit = if error_codes.len() > 9 { 9 } else { error_codes.len() };
 846                     self.failure(&format!(
 847                         "Some errors have detailed explanations: {}{}",
 848                         error_codes[..limit].join(", "),
 849                         if error_codes.len() > 9 { "..." } else { "." }
 850                     ));
 851                     self.failure(&format!(
 852                         "For more information about an error, try \
 853                          `rustc --explain {}`.",
 854                         &error_codes[0]
 855                     ));
 856                 } else {
 857                     self.failure(&format!(
 858                         "For more information about this error, try \
 859                          `rustc --explain {}`.",
 860                         &error_codes[0]
 861                     ));
 862                 }
 863             }
 864         }
 865     }
 866
 867     fn err_count(&self) -> usize {
 868         self.err_count + self.stashed_diagnostics.len()
 869     }
 870
 871     fn has_errors(&self) -> bool {
 872         self.err_count() > 0
 873     }
 874     fn has_errors_or_delayed_span_bugs(&self) -> bool {
 875         self.has_errors() || !self.delayed_span_bugs.is_empty()
 876     }
 877     fn has_any_message(&self) -> bool {
 878         self.err_count() > 0 || self.warn_count > 0
 879     }
 880
 881     fn abort_if_errors(&mut self) {
 882         self.emit_stashed_diagnostics();
 883
 884         if self.has_errors() {
 885             FatalError.raise();
 886         }
 887     }
 888
 889     fn span_bug(&mut self, sp: impl Into<MultiSpan>, msg: &str) -> ! {
 890         self.emit_diag_at_span(Diagnostic::new(Bug, msg), sp);
 891         panic!(ExplicitBug);
 892     }
 893
 894     fn emit_diag_at_span(&mut self, mut diag: Diagnostic, sp: impl Into<MultiSpan>) {
 895         self.emit_diagnostic(diag.set_span(sp));
 896     }
 897
 898     #[track_caller]
 899     fn delay_span_bug(&mut self, sp: impl Into<MultiSpan>, msg: &str) {
 900         // This is technically `self.treat_err_as_bug()` but `delay_span_bug` is called before
 901         // incrementing `err_count` by one, so we need to +1 the comparing.
 902         // FIXME: Would be nice to increment err_count in a more coherent way.
 903         if self.flags.treat_err_as_bug.map(|c| self.err_count() + 1 >= c).unwrap_or(false) {
 904             // FIXME: don't abort here if report_delayed_bugs is off
 905             self.span_bug(sp, msg);
 906         }
 907         let mut diagnostic = Diagnostic::new(Level::Bug, msg);
 908         diagnostic.set_span(sp.into());
 909         diagnostic.note(&format!("delayed at {}", std::panic::Location::caller()));
 910         self.delay_as_bug(diagnostic)
 911     }
 912
 913     fn delay_good_path_bug(&mut self, msg: &str) {
 914         let mut diagnostic = Diagnostic::new(Level::Bug, msg);
 915         if self.flags.report_delayed_bugs {
 916             self.emit_diagnostic(&diagnostic);
 917         }
 918         diagnostic.note(&format!("delayed at {}", std::backtrace::Backtrace::force_capture()));
 919         self.delayed_good_path_bugs.push(diagnostic);
 920     }
 921
 922     fn failure(&mut self, msg: &str) {
 923         self.emit_diagnostic(&Diagnostic::new(FailureNote, msg));
 924     }
 925
 926     fn fatal(&mut self, msg: &str) -> FatalError {
 927         self.emit_error(Fatal, msg);
 928         FatalError
 929     }
 930
 931     fn err(&mut self, msg: &str) {
 932         self.emit_error(Error, msg);
 933     }
 934
 935     /// Emit an error; level should be `Error` or `Fatal`.
 936     fn emit_error(&mut self, level: Level, msg: &str) {
 937         if self.treat_err_as_bug() {
 938             self.bug(msg);
 939         }
 940         self.emit_diagnostic(&Diagnostic::new(level, msg));
 941     }
 942
 943     fn bug(&mut self, msg: &str) -> ! {
 944         self.emit_diagnostic(&Diagnostic::new(Bug, msg));
 945         panic!(ExplicitBug);
 946     }
 947
 948     fn delay_as_bug(&mut self, diagnostic: Diagnostic) {
 949         if self.flags.report_delayed_bugs {
 950             self.emit_diagnostic(&diagnostic);
 951         }
 952         self.delayed_span_bugs.push(diagnostic);
 953     }
 954
 955     fn flush_delayed(&mut self, bugs: Vec<Diagnostic>, explanation: &str) {
 956         let has_bugs = !bugs.is_empty();
 957         for bug in bugs {
 958             self.emit_diagnostic(&bug);
 959         }
 960         if has_bugs {
 961             panic!("{}", explanation);
 962         }
 963     }
 964
 965     fn bump_err_count(&mut self) {
 966         self.err_count += 1;
 967         self.panic_if_treat_err_as_bug();
 968     }
 969
 970     fn bump_warn_count(&mut self) {
 971         self.warn_count += 1;
 972     }
 973
 974     fn panic_if_treat_err_as_bug(&self) {
 975         if self.treat_err_as_bug() {
 976             match (self.err_count(), self.flags.treat_err_as_bug.unwrap_or(0)) {
 977                 (1, 1) => panic!("aborting due to `-Z treat-err-as-bug=1`"),
 978                 (0, _) | (1, _) => {}
 979                 (count, as_bug) => panic!(
 980                     "aborting after {} errors due to `-Z treat-err-as-bug={}`",
 981                     count, as_bug,
 982                 ),
 983             }
 984         }
 985     }
 986 }
 987
 988 #[derive(Copy, PartialEq, Clone, Hash, Debug, Encodable, Decodable)]
 989 pub enum Level {
 990     Bug,
 991     Fatal,
 992     Error,
 993     Warning,
 994     Note,
 995     Help,
 996     Cancelled,
 997     FailureNote,
 998 }
 999
1000 impl fmt::Display for Level {
1001     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1002         self.to_str().fmt(f)
1003     }
1004 }
1005
1006 impl Level {
1007     fn color(self) -> ColorSpec {
1008         let mut spec = ColorSpec::new();
1009         match self {
1010             Bug | Fatal | Error => {
1011                 spec.set_fg(Some(Color::Red)).set_intense(true);
1012             }
1013             Warning => {
1014                 spec.set_fg(Some(Color::Yellow)).set_intense(cfg!(windows));
1015             }
1016             Note => {
1017                 spec.set_fg(Some(Color::Green)).set_intense(true);
1018             }
1019             Help => {
1020                 spec.set_fg(Some(Color::Cyan)).set_intense(true);
1021             }
1022             FailureNote => {}
1023             Cancelled => unreachable!(),
1024         }
1025         spec
1026     }
1027
1028     pub fn to_str(self) -> &'static str {
1029         match self {
1030             Bug => "error: internal compiler error",
1031             Fatal | Error => "error",
1032             Warning => "warning",
1033             Note => "note",
1034             Help => "help",
1035             FailureNote => "failure-note",
1036             Cancelled => panic!("Shouldn't call on cancelled error"),
1037         }
1038     }
1039
1040     pub fn is_failure_note(&self) -> bool {
1041         match *self {
1042             FailureNote => true,
1043             _ => false,
1044         }
1045     }
1046 }
1047
1048 #[macro_export]
1049 macro_rules! pluralize {
1050     ($x:expr) => {
1051         if $x != 1 { "s" } else { "" }
1052     };
1053 }
1054
1055 // Useful type to use with `Result<>` indicate that an error has already
1056 // been reported to the user, so no need to continue checking.
1057 #[derive(Clone, Copy, Debug, Encodable, Decodable, Hash, PartialEq, Eq)]
1058 pub struct ErrorReported;
1059
1060 rustc_data_structures::impl_stable_hash_via_hash!(ErrorReported);