1 //! The current rustc diagnostics emitter.
3 //! An `Emitter` takes care of generating the output from a `DiagnosticBuilder` struct.
5 //! There are various `Emitter` implementations that generate different output formats such as
6 //! JSON and human readable output.
8 //! The output types are defined in `rustc_session::config::ErrorOutputType`.
12 use rustc_span::source_map::SourceMap;
13 use rustc_span::{SourceFile, Span};
15 use crate::snippet::{Annotation, AnnotationType, Line, MultilineAnnotation, Style, StyledString};
16 use crate::styled_buffer::StyledBuffer;
18 CodeSuggestion, Diagnostic, DiagnosticArg, DiagnosticId, DiagnosticMessage, FluentBundle,
19 Handler, Level, MultiSpan, SubDiagnostic, SubstitutionHighlight, SuggestionStyle,
22 use rustc_lint_defs::pluralize;
24 use rustc_data_structures::fx::FxHashMap;
25 use rustc_data_structures::sync::Lrc;
26 use rustc_error_messages::FluentArgs;
27 use rustc_span::hygiene::{ExpnKind, MacroKind};
29 use std::cmp::{max, min, Reverse};
31 use std::io::prelude::*;
34 use termcolor::{Ansi, BufferWriter, ColorChoice, ColorSpec, StandardStream};
35 use termcolor::{Buffer, Color, WriteColor};
38 /// Default column width, used in tests and when terminal dimensions cannot be determined.
39 const DEFAULT_COLUMN_WIDTH: usize = 140;
41 /// Describes the way the content of the `rendered` field of the json output is generated
42 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
43 pub enum HumanReadableErrorType {
45 AnnotateSnippet(ColorConfig),
49 impl HumanReadableErrorType {
50 /// Returns a (`short`, `color`) tuple
51 pub fn unzip(self) -> (bool, ColorConfig) {
53 HumanReadableErrorType::Default(cc) => (false, cc),
54 HumanReadableErrorType::Short(cc) => (true, cc),
55 HumanReadableErrorType::AnnotateSnippet(cc) => (false, cc),
60 dst: Box<dyn Write + Send>,
61 source_map: Option<Lrc<SourceMap>>,
62 bundle: Option<Lrc<FluentBundle>>,
63 fallback_bundle: Lrc<FluentBundle>,
65 terminal_width: Option<usize>,
66 macro_backtrace: bool,
68 let (short, color_config) = self.unzip();
69 let color = color_config.suggests_using_colors();
84 #[derive(Clone, Copy, Debug)]
86 /// The available whitespace in the left that can be consumed when centering.
87 pub whitespace_left: usize,
88 /// The column of the beginning of left-most span.
90 /// The column of the end of right-most span.
91 pub span_right: usize,
92 /// The beginning of the line to be displayed.
93 pub computed_left: usize,
94 /// The end of the line to be displayed.
95 pub computed_right: usize,
96 /// The current width of the terminal. Uses value of `DEFAULT_COLUMN_WIDTH` constant by default
98 pub column_width: usize,
99 /// The end column of a span label, including the span. Doesn't account for labels not in the
100 /// same line as the span.
101 pub label_right: usize,
106 whitespace_left: usize,
113 // The 6 is padding to give a bit of room for `...` when displaying:
118 // 16 | ... fn foo(self) -> Self::Bar {
123 whitespace_left: whitespace_left.saturating_sub(6),
124 span_left: span_left.saturating_sub(6),
125 span_right: span_right + 6,
129 label_right: label_right + 6,
131 m.compute(max_line_len);
135 fn was_cut_left(&self) -> bool {
136 self.computed_left > 0
139 fn was_cut_right(&self, line_len: usize) -> bool {
141 if self.computed_right == self.span_right || self.computed_right == self.label_right {
142 // Account for the "..." padding given above. Otherwise we end up with code lines that
143 // do fit but end in "..." as if they were trimmed.
144 self.computed_right - 6
148 right < line_len && self.computed_left + self.column_width < line_len
151 fn compute(&mut self, max_line_len: usize) {
152 // When there's a lot of whitespace (>20), we want to trim it as it is useless.
153 self.computed_left = if self.whitespace_left > 20 {
154 self.whitespace_left - 16 // We want some padding.
158 // We want to show as much as possible, max_line_len is the right-most boundary for the
160 self.computed_right = max(max_line_len, self.computed_left);
162 if self.computed_right - self.computed_left > self.column_width {
163 // Trimming only whitespace isn't enough, let's get craftier.
164 if self.label_right - self.whitespace_left <= self.column_width {
165 // Attempt to fit the code window only trimming whitespace.
166 self.computed_left = self.whitespace_left;
167 self.computed_right = self.computed_left + self.column_width;
168 } else if self.label_right - self.span_left <= self.column_width {
169 // Attempt to fit the code window considering only the spans and labels.
170 let padding_left = (self.column_width - (self.label_right - self.span_left)) / 2;
171 self.computed_left = self.span_left.saturating_sub(padding_left);
172 self.computed_right = self.computed_left + self.column_width;
173 } else if self.span_right - self.span_left <= self.column_width {
174 // Attempt to fit the code window considering the spans and labels plus padding.
175 let padding_left = (self.column_width - (self.span_right - self.span_left)) / 5 * 2;
176 self.computed_left = self.span_left.saturating_sub(padding_left);
177 self.computed_right = self.computed_left + self.column_width;
179 // Mostly give up but still don't show the full line.
180 self.computed_left = self.span_left;
181 self.computed_right = self.span_right;
186 fn left(&self, line_len: usize) -> usize {
187 min(self.computed_left, line_len)
190 fn right(&self, line_len: usize) -> usize {
191 if line_len.saturating_sub(self.computed_left) <= self.column_width {
194 min(line_len, self.computed_right)
199 const ANONYMIZED_LINE_NUM: &str = "LL";
201 /// Emitter trait for emitting errors.
203 /// Emit a structured diagnostic.
204 fn emit_diagnostic(&mut self, diag: &Diagnostic);
206 /// Emit a notification that an artifact has been output.
207 /// This is currently only supported for the JSON format,
208 /// other formats can, and will, simply ignore it.
209 fn emit_artifact_notification(&mut self, _path: &Path, _artifact_type: &str) {}
211 fn emit_future_breakage_report(&mut self, _diags: Vec<Diagnostic>) {}
213 /// Emit list of unused externs
214 fn emit_unused_externs(&mut self, _lint_level: &str, _unused_externs: &[&str]) {}
216 /// Checks if should show explanations about "rustc --explain"
217 fn should_show_explain(&self) -> bool {
221 /// Checks if we can use colors in the current output stream.
222 fn supports_color(&self) -> bool {
226 fn source_map(&self) -> Option<&Lrc<SourceMap>>;
228 /// Return `FluentBundle` with localized diagnostics for the locale requested by the user. If no
229 /// language was requested by the user then this will be `None` and `fallback_fluent_bundle`
231 fn fluent_bundle(&self) -> Option<&Lrc<FluentBundle>>;
233 /// Return `FluentBundle` with localized diagnostics for the default locale of the compiler.
234 /// Used when the user has not requested a specific language or when a localized diagnostic is
235 /// unavailable for the requested locale.
236 fn fallback_fluent_bundle(&self) -> &Lrc<FluentBundle>;
238 /// Convert diagnostic arguments (a rustc internal type that exists to implement
239 /// `Encodable`/`Decodable`) into `FluentArgs` which is necessary to perform translation.
241 /// Typically performed once for each diagnostic at the start of `emit_diagnostic` and then
242 /// passed around as a reference thereafter.
243 fn to_fluent_args<'arg>(&self, args: &[DiagnosticArg<'arg>]) -> FluentArgs<'arg> {
244 FromIterator::from_iter(args.to_vec().drain(..))
247 /// Convert `DiagnosticMessage`s to a string, performing translation if necessary.
248 fn translate_messages(
250 messages: &[(DiagnosticMessage, Style)],
251 args: &FluentArgs<'_>,
254 messages.iter().map(|(m, _)| self.translate_message(m, args)).collect::<String>(),
258 /// Convert a `DiagnosticMessage` to a string, performing translation if necessary.
259 fn translate_message<'a>(
261 message: &'a DiagnosticMessage,
262 args: &'a FluentArgs<'_>,
264 trace!(?message, ?args);
265 let (identifier, attr) = match message {
266 DiagnosticMessage::Str(msg) => return Cow::Borrowed(&msg),
267 DiagnosticMessage::FluentIdentifier(identifier, attr) => (identifier, attr),
270 let bundle = match self.fluent_bundle() {
271 Some(bundle) if bundle.has_message(&identifier) => bundle,
272 _ => self.fallback_fluent_bundle(),
275 let message = bundle.get_message(&identifier).expect("missing diagnostic in fluent bundle");
276 let value = match attr {
278 message.get_attribute(attr).expect("missing attribute in fluent message").value()
280 None => message.value().expect("missing value in fluent message"),
283 let mut err = vec![];
284 let translated = bundle.format_pattern(value, Some(&args), &mut err);
285 trace!(?translated, ?err);
288 "identifier: {:?}, args: {:?}, errors: {:?}",
296 /// Formats the substitutions of the primary_span
298 /// There are a lot of conditions to this method, but in short:
300 /// * If the current `Diagnostic` has only one visible `CodeSuggestion`,
301 /// we format the `help` suggestion depending on the content of the
302 /// substitutions. In that case, we return the modified span only.
304 /// * If the current `Diagnostic` has multiple suggestions,
305 /// we return the original `primary_span` and the original suggestions.
306 fn primary_span_formatted<'a>(
308 diag: &'a Diagnostic,
309 fluent_args: &FluentArgs<'_>,
310 ) -> (MultiSpan, &'a [CodeSuggestion]) {
311 let mut primary_span = diag.span.clone();
312 let suggestions = diag.suggestions.as_ref().map_or(&[][..], |suggestions| &suggestions[..]);
313 if let Some((sugg, rest)) = suggestions.split_first() {
314 let msg = self.translate_message(&sugg.msg, fluent_args);
315 if rest.is_empty() &&
316 // ^ if there is only one suggestion
317 // don't display multi-suggestions as labels
318 sugg.substitutions.len() == 1 &&
319 // don't display multipart suggestions as labels
320 sugg.substitutions[0].parts.len() == 1 &&
321 // don't display long messages as labels
322 msg.split_whitespace().count() < 10 &&
323 // don't display multiline suggestions as labels
324 !sugg.substitutions[0].parts[0].snippet.contains('\n') &&
326 // when this style is set we want the suggestion to be a message, not inline
327 SuggestionStyle::HideCodeAlways,
328 // trivial suggestion for tooling's sake, never shown
329 SuggestionStyle::CompletelyHidden,
330 // subtle suggestion, never shown inline
331 SuggestionStyle::ShowAlways,
332 ].contains(&sugg.style)
334 let substitution = &sugg.substitutions[0].parts[0].snippet.trim();
335 let msg = if substitution.is_empty() || sugg.style.hide_inline() {
336 // This substitution is only removal OR we explicitly don't want to show the
337 // code inline (`hide_inline`). Therefore, we don't show the substitution.
338 format!("help: {}", &msg)
340 // Show the default suggestion text with the substitution
346 .map(|sm| is_case_difference(
349 sugg.substitutions[0].parts[0].span,
353 " (notice the capitalization)"
360 primary_span.push_span_label(sugg.substitutions[0].parts[0].span, msg);
362 // We return only the modified primary_span
365 // if there are multiple suggestions, print them all in full
366 // to be consistent. We could try to figure out if we can
367 // make one (or the first one) inline, but that would give
368 // undue importance to a semi-random suggestion
369 (primary_span, suggestions)
372 (primary_span, suggestions)
376 fn fix_multispans_in_extern_macros_and_render_macro_backtrace(
378 source_map: &Option<Lrc<SourceMap>>,
379 span: &mut MultiSpan,
380 children: &mut Vec<SubDiagnostic>,
384 // Check for spans in macros, before `fix_multispans_in_extern_macros`
385 // has a chance to replace them.
386 let has_macro_spans = iter::once(&*span)
387 .chain(children.iter().map(|child| &child.span))
388 .flat_map(|span| span.primary_spans())
389 .flat_map(|sp| sp.macro_backtrace())
390 .find_map(|expn_data| {
391 match expn_data.kind {
392 ExpnKind::Root => None,
394 // Skip past non-macro entries, just in case there
395 // are some which do actually involve macros.
396 ExpnKind::Inlined | ExpnKind::Desugaring(..) | ExpnKind::AstPass(..) => None,
398 ExpnKind::Macro(macro_kind, name) => Some((macro_kind, name)),
403 self.fix_multispans_in_extern_macros(source_map, span, children);
406 self.render_multispans_macro_backtrace(span, children, backtrace);
409 if let Some((macro_kind, name)) = has_macro_spans {
410 let descr = macro_kind.descr();
413 "this {level} originates in the {descr} `{name}` \
414 (in Nightly builds, run with -Z macro-backtrace for more info)",
417 children.push(SubDiagnostic {
419 message: vec![(DiagnosticMessage::Str(msg), Style::NoStyle)],
420 span: MultiSpan::new(),
427 fn render_multispans_macro_backtrace(
429 span: &mut MultiSpan,
430 children: &mut Vec<SubDiagnostic>,
433 for span in iter::once(span).chain(children.iter_mut().map(|child| &mut child.span)) {
434 self.render_multispan_macro_backtrace(span, backtrace);
438 fn render_multispan_macro_backtrace(&self, span: &mut MultiSpan, always_backtrace: bool) {
439 let mut new_labels: Vec<(Span, String)> = vec![];
441 for &sp in span.primary_spans() {
446 // FIXME(eddyb) use `retain` on `macro_backtrace` to remove all the
447 // entries we don't want to print, to make sure the indices being
448 // printed are contiguous (or omitted if there's only one entry).
449 let macro_backtrace: Vec<_> = sp.macro_backtrace().collect();
450 for (i, trace) in macro_backtrace.iter().rev().enumerate() {
451 if trace.def_site.is_dummy() {
455 if always_backtrace && !matches!(trace.kind, ExpnKind::Inlined) {
459 "in this expansion of `{}`{}",
461 if macro_backtrace.len() > 1 {
462 // if macro_backtrace.len() == 1 it'll be
463 // pointed at by "in this macro invocation"
464 format!(" (#{})", i + 1)
472 // Don't add a label on the call site if the diagnostic itself
473 // already points to (a part of) that call site, as the label
474 // is meant for showing the relevant invocation when the actual
475 // diagnostic is pointing to some part of macro definition.
477 // This also handles the case where an external span got replaced
478 // with the call site span by `fix_multispans_in_extern_macros`.
480 // NB: `-Zmacro-backtrace` overrides this, for uniformity, as the
481 // "in this expansion of" label above is always added in that mode,
482 // and it needs an "in this macro invocation" label to match that.
483 let redundant_span = trace.call_site.contains(sp);
485 if !redundant_span || always_backtrace {
486 let msg: Cow<'static, _> = match trace.kind {
487 ExpnKind::Macro(MacroKind::Attr, _) => {
488 "this procedural macro expansion".into()
490 ExpnKind::Macro(MacroKind::Derive, _) => {
491 "this derive macro expansion".into()
493 ExpnKind::Macro(MacroKind::Bang, _) => "this macro invocation".into(),
494 ExpnKind::Inlined => "this inlined function call".into(),
495 ExpnKind::Root => "the crate root".into(),
496 ExpnKind::AstPass(kind) => kind.descr().into(),
497 ExpnKind::Desugaring(kind) => {
498 format!("this {} desugaring", kind.descr()).into()
506 if macro_backtrace.len() > 1 && always_backtrace {
507 // only specify order when the macro
508 // backtrace is multiple levels deep
509 format!(" (#{})", i + 1)
516 if !always_backtrace {
522 for (label_span, label_text) in new_labels {
523 span.push_span_label(label_span, label_text);
527 // This does a small "fix" for multispans by looking to see if it can find any that
528 // point directly at external macros. Since these are often difficult to read,
529 // this will change the span to point at the use site.
530 fn fix_multispans_in_extern_macros(
532 source_map: &Option<Lrc<SourceMap>>,
533 span: &mut MultiSpan,
534 children: &mut Vec<SubDiagnostic>,
536 let Some(source_map) = source_map else { return };
537 debug!("fix_multispans_in_extern_macros: before: span={:?} children={:?}", span, children);
538 self.fix_multispan_in_extern_macros(source_map, span);
539 for child in children.iter_mut() {
540 self.fix_multispan_in_extern_macros(source_map, &mut child.span);
542 debug!("fix_multispans_in_extern_macros: after: span={:?} children={:?}", span, children);
545 // This "fixes" MultiSpans that contain `Span`s pointing to locations inside of external macros.
546 // Since these locations are often difficult to read,
547 // we move these spans from the external macros to their corresponding use site.
548 fn fix_multispan_in_extern_macros(&self, source_map: &Lrc<SourceMap>, span: &mut MultiSpan) {
549 // First, find all the spans in external macros and point instead at their use site.
550 let replacements: Vec<(Span, Span)> = span
554 .chain(span.span_labels().iter().map(|sp_label| sp_label.span))
556 if !sp.is_dummy() && source_map.is_imported(sp) {
557 let maybe_callsite = sp.source_callsite();
558 if sp != maybe_callsite {
559 return Some((sp, maybe_callsite));
566 // After we have them, make sure we replace these 'bad' def sites with their use sites.
567 for (from, to) in replacements {
568 span.replace(from, to);
573 impl Emitter for EmitterWriter {
574 fn source_map(&self) -> Option<&Lrc<SourceMap>> {
578 fn fluent_bundle(&self) -> Option<&Lrc<FluentBundle>> {
579 self.fluent_bundle.as_ref()
582 fn fallback_fluent_bundle(&self) -> &Lrc<FluentBundle> {
583 &self.fallback_bundle
586 fn emit_diagnostic(&mut self, diag: &Diagnostic) {
587 let fluent_args = self.to_fluent_args(diag.args());
589 let mut children = diag.children.clone();
590 let (mut primary_span, suggestions) = self.primary_span_formatted(&diag, &fluent_args);
591 debug!("emit_diagnostic: suggestions={:?}", suggestions);
593 self.fix_multispans_in_extern_macros_and_render_macro_backtrace(
598 self.macro_backtrace,
601 self.emit_messages_default(
612 fn should_show_explain(&self) -> bool {
616 fn supports_color(&self) -> bool {
617 self.dst.supports_color()
621 /// An emitter that does nothing when emitting a non-fatal diagnostic.
622 /// Fatal diagnostics are forwarded to `fatal_handler` to avoid silent
623 /// failures of rustc, as witnessed e.g. in issue #89358.
624 pub struct SilentEmitter {
625 pub fatal_handler: Handler,
626 pub fatal_note: Option<String>,
629 impl Emitter for SilentEmitter {
630 fn source_map(&self) -> Option<&Lrc<SourceMap>> {
634 fn fluent_bundle(&self) -> Option<&Lrc<FluentBundle>> {
638 fn fallback_fluent_bundle(&self) -> &Lrc<FluentBundle> {
639 panic!("silent emitter attempted to translate message")
642 fn emit_diagnostic(&mut self, d: &Diagnostic) {
643 if d.level == Level::Fatal {
644 let mut d = d.clone();
645 if let Some(ref note) = self.fatal_note {
648 self.fatal_handler.emit_diagnostic(&mut d);
653 /// Maximum number of lines we will print for a multiline suggestion; arbitrary.
655 /// This should be replaced with a more involved mechanism to output multiline suggestions that
656 /// more closely mimics the regular diagnostic output, where irrelevant code lines are elided.
657 pub const MAX_SUGGESTION_HIGHLIGHT_LINES: usize = 6;
658 /// Maximum number of suggestions to be shown
660 /// Arbitrary, but taken from trait import suggestion limit
661 pub const MAX_SUGGESTIONS: usize = 4;
663 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
664 pub enum ColorConfig {
671 fn to_color_choice(self) -> ColorChoice {
673 ColorConfig::Always => {
674 if atty::is(atty::Stream::Stderr) {
677 ColorChoice::AlwaysAnsi
680 ColorConfig::Never => ColorChoice::Never,
681 ColorConfig::Auto if atty::is(atty::Stream::Stderr) => ColorChoice::Auto,
682 ColorConfig::Auto => ColorChoice::Never,
685 fn suggests_using_colors(self) -> bool {
687 ColorConfig::Always | ColorConfig::Auto => true,
688 ColorConfig::Never => false,
693 /// Handles the writing of `HumanReadableErrorType::Default` and `HumanReadableErrorType::Short`
694 pub struct EmitterWriter {
696 sm: Option<Lrc<SourceMap>>,
697 fluent_bundle: Option<Lrc<FluentBundle>>,
698 fallback_bundle: Lrc<FluentBundle>,
702 terminal_width: Option<usize>,
704 macro_backtrace: bool,
708 pub struct FileWithAnnotatedLines {
709 pub file: Lrc<SourceFile>,
710 pub lines: Vec<Line>,
711 multiline_depth: usize,
716 color_config: ColorConfig,
717 source_map: Option<Lrc<SourceMap>>,
718 fluent_bundle: Option<Lrc<FluentBundle>>,
719 fallback_bundle: Lrc<FluentBundle>,
722 terminal_width: Option<usize>,
723 macro_backtrace: bool,
725 let dst = Destination::from_stderr(color_config);
740 dst: Box<dyn Write + Send>,
741 source_map: Option<Lrc<SourceMap>>,
742 fluent_bundle: Option<Lrc<FluentBundle>>,
743 fallback_bundle: Lrc<FluentBundle>,
747 terminal_width: Option<usize>,
748 macro_backtrace: bool,
751 dst: Raw(dst, colored),
763 pub fn ui_testing(mut self, ui_testing: bool) -> Self {
764 self.ui_testing = ui_testing;
768 fn maybe_anonymized(&self, line_num: usize) -> String {
769 if self.ui_testing { ANONYMIZED_LINE_NUM.to_string() } else { line_num.to_string() }
774 buffer: &mut StyledBuffer,
782 // Tabs are assumed to have been replaced by spaces in calling code.
783 debug_assert!(!source_string.contains('\t'));
784 let line_len = source_string.len();
785 // Create the source line we will highlight.
786 let left = margin.left(line_len);
787 let right = margin.right(line_len);
788 // On long lines, we strip the source line, accounting for unicode.
790 let code: String = source_string
794 // Make sure that the trimming on the right will fall within the terminal width.
795 // FIXME: `unicode_width` sometimes disagrees with terminals on how wide a `char` is.
796 // For now, just accept that sometimes the code line will be longer than desired.
797 let next = unicode_width::UnicodeWidthChar::width(*ch).unwrap_or(1);
798 if taken + next > right - left {
805 buffer.puts(line_offset, code_offset, &code, Style::Quotation);
806 if margin.was_cut_left() {
807 // We have stripped some code/whitespace from the beginning, make it clear.
808 buffer.puts(line_offset, code_offset, "...", Style::LineNumber);
810 if margin.was_cut_right(line_len) {
811 // We have stripped some code after the right-most span end, make it clear we did so.
812 buffer.puts(line_offset, code_offset + taken - 3, "...", Style::LineNumber);
814 buffer.puts(line_offset, 0, &self.maybe_anonymized(line_index), Style::LineNumber);
816 draw_col_separator(buffer, line_offset, width_offset - 2);
819 fn render_source_line(
821 buffer: &mut StyledBuffer,
822 file: Lrc<SourceFile>,
827 ) -> Vec<(usize, Style)> {
833 // | secondary span label
835 // ^^ ^ ^^^ ^^^^ ^^^ we don't care about code too far to the right of a span, we trim it
837 // | | | actual code found in your source code and the spans we use to mark it
838 // | | when there's too much wasted space to the left, trim it
839 // | vertical divider between the column number and the code
842 if line.line_index == 0 {
846 let source_string = match file.get_line(line.line_index - 1) {
847 Some(s) => normalize_whitespace(&*s),
848 None => return Vec::new(),
851 let line_offset = buffer.num_lines();
854 let left = margin.left(source_string.len());
856 // Account for unicode characters of width !=0 that were removed.
857 let left = source_string
860 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
873 // Special case when there's only one annotation involved, it is the start of a multiline
874 // span and there's no text at the beginning of the code line. Instead of doing the whole
883 // we simplify the output to:
889 if let [ann] = &line.annotations[..] {
890 if let AnnotationType::MultilineStart(depth) = ann.annotation_type {
891 if source_string.chars().take(ann.start_col).all(|c| c.is_whitespace()) {
892 let style = if ann.is_primary {
893 Style::UnderlinePrimary
895 Style::UnderlineSecondary
897 buffer.putc(line_offset, width_offset + depth - 1, '/', style);
898 return vec![(depth, style)];
903 // We want to display like this:
905 // vec.push(vec.pop().unwrap());
906 // --- ^^^ - previous borrow ends here
908 // | error occurs here
909 // previous borrow of `vec` occurs here
911 // But there are some weird edge cases to be aware of:
913 // vec.push(vec.pop().unwrap());
914 // -------- - previous borrow ends here
916 // |this makes no sense
917 // previous borrow of `vec` occurs here
919 // For this reason, we group the lines into "highlight lines"
920 // and "annotations lines", where the highlight lines have the `^`.
922 // Sort the annotations by (start, end col)
923 // The labels are reversed, sort and then reversed again.
924 // Consider a list of annotations (A1, A2, C1, C2, B1, B2) where
925 // the letter signifies the span. Here we are only sorting by the
926 // span and hence, the order of the elements with the same span will
927 // not change. On reversing the ordering (|a, b| but b.cmp(a)), you get
928 // (C1, C2, B1, B2, A1, A2). All the elements with the same span are
929 // still ordered first to last, but all the elements with different
930 // spans are ordered by their spans in last to first order. Last to
931 // first order is important, because the jiggly lines and | are on
932 // the left, so the rightmost span needs to be rendered first,
933 // otherwise the lines would end up needing to go over a message.
935 let mut annotations = line.annotations.clone();
936 annotations.sort_by_key(|a| Reverse(a.start_col));
938 // First, figure out where each label will be positioned.
940 // In the case where you have the following annotations:
942 // vec.push(vec.pop().unwrap());
943 // -------- - previous borrow ends here [C]
945 // |this makes no sense [B]
946 // previous borrow of `vec` occurs here [A]
948 // `annotations_position` will hold [(2, A), (1, B), (0, C)].
950 // We try, when possible, to stick the rightmost annotation at the end
951 // of the highlight line:
953 // vec.push(vec.pop().unwrap());
954 // --- --- - previous borrow ends here
956 // But sometimes that's not possible because one of the other
957 // annotations overlaps it. For example, from the test
958 // `span_overlap_label`, we have the following annotations
959 // (written on distinct lines for clarity):
965 // In this case, we can't stick the rightmost-most label on
966 // the highlight line, or we would get:
973 // which is totally weird. Instead we want:
981 // which is...less weird, at least. In fact, in general, if
982 // the rightmost span overlaps with any other span, we should
983 // use the "hang below" version, so we can at least make it
984 // clear where the span *starts*. There's an exception for this
985 // logic, when the labels do not have a message:
1000 let mut annotations_position = vec![];
1001 let mut line_len = 0;
1003 for (i, annotation) in annotations.iter().enumerate() {
1004 for (j, next) in annotations.iter().enumerate() {
1005 if overlaps(next, annotation, 0) // This label overlaps with another one and both
1006 && annotation.has_label() // take space (they have text and are not
1007 && j > i // multiline lines).
1009 // We're currently on the first line, move the label one line down
1011 // If we're overlapping with an un-labelled annotation with the same span
1012 // we can just merge them in the output
1013 if next.start_col == annotation.start_col
1014 && next.end_col == annotation.end_col
1015 && !next.has_label()
1020 // This annotation needs a new line in the output.
1025 annotations_position.push((p, annotation));
1026 for (j, next) in annotations.iter().enumerate() {
1028 let l = next.label.as_ref().map_or(0, |label| label.len() + 2);
1029 if (overlaps(next, annotation, l) // Do not allow two labels to be in the same
1030 // line if they overlap including padding, to
1031 // avoid situations like:
1038 && annotation.has_label() // Both labels must have some text, otherwise
1039 && next.has_label()) // they are not overlapping.
1040 // Do not add a new line if this annotation
1041 // or the next are vertical line placeholders.
1042 || (annotation.takes_space() // If either this or the next annotation is
1043 && next.has_label()) // multiline start/end, move it to a new line
1044 || (annotation.has_label() // so as not to overlap the horizontal lines.
1045 && next.takes_space())
1046 || (annotation.takes_space() && next.takes_space())
1047 || (overlaps(next, annotation, l)
1048 && next.end_col <= annotation.end_col
1053 // This annotation needs a new line in the output.
1059 line_len = max(line_len, p);
1066 // If there are no annotations or the only annotations on this line are
1067 // MultilineLine, then there's only code being shown, stop processing.
1068 if line.annotations.iter().all(|a| a.is_line()) {
1072 // Write the column separator.
1074 // After this we will have:
1083 for pos in 0..=line_len {
1084 draw_col_separator(buffer, line_offset + pos + 1, width_offset - 2);
1087 // Write the horizontal lines for multiline annotations
1088 // (only the first and last lines need this).
1090 // After this we will have:
1099 for &(pos, annotation) in &annotations_position {
1100 let style = if annotation.is_primary {
1101 Style::UnderlinePrimary
1103 Style::UnderlineSecondary
1106 match annotation.annotation_type {
1107 AnnotationType::MultilineStart(depth) | AnnotationType::MultilineEnd(depth) => {
1112 width_offset + depth,
1113 (code_offset + annotation.start_col).saturating_sub(left),
1117 _ if self.teach => {
1118 buffer.set_style_range(
1120 (code_offset + annotation.start_col).saturating_sub(left),
1121 (code_offset + annotation.end_col).saturating_sub(left),
1123 annotation.is_primary,
1130 // Write the vertical lines for labels that are on a different line as the underline.
1132 // After this we will have:
1141 for &(pos, annotation) in &annotations_position {
1142 let style = if annotation.is_primary {
1143 Style::UnderlinePrimary
1145 Style::UnderlineSecondary
1149 if pos > 1 && (annotation.has_label() || annotation.takes_space()) {
1150 for p in line_offset + 1..=line_offset + pos {
1153 (code_offset + annotation.start_col).saturating_sub(left),
1159 match annotation.annotation_type {
1160 AnnotationType::MultilineStart(depth) => {
1161 for p in line_offset + pos + 1..line_offset + line_len + 2 {
1162 buffer.putc(p, width_offset + depth - 1, '|', style);
1165 AnnotationType::MultilineEnd(depth) => {
1166 for p in line_offset..=line_offset + pos {
1167 buffer.putc(p, width_offset + depth - 1, '|', style);
1174 // Write the labels on the annotations that actually have a label.
1176 // After this we will have:
1181 // | something about `foo`
1185 for &(pos, annotation) in &annotations_position {
1187 if annotation.is_primary { Style::LabelPrimary } else { Style::LabelSecondary };
1188 let (pos, col) = if pos == 0 {
1189 (pos + 1, (annotation.end_col + 1).saturating_sub(left))
1191 (pos + 2, annotation.start_col.saturating_sub(left))
1193 if let Some(ref label) = annotation.label {
1194 buffer.puts(line_offset + pos, code_offset + col, &label, style);
1198 // Sort from biggest span to smallest span so that smaller spans are
1199 // represented in the output:
1204 // | | something about `foo`
1205 // | something about `fn foo()`
1206 annotations_position.sort_by_key(|(_, ann)| {
1207 // Decreasing order. When annotations share the same length, prefer `Primary`.
1208 (Reverse(ann.len()), ann.is_primary)
1211 // Write the underlines.
1213 // After this we will have:
1218 // | something about `foo`
1222 for &(_, annotation) in &annotations_position {
1223 let (underline, style) = if annotation.is_primary {
1224 ('^', Style::UnderlinePrimary)
1226 ('-', Style::UnderlineSecondary)
1228 for p in annotation.start_col..annotation.end_col {
1231 (code_offset + p).saturating_sub(left),
1237 annotations_position
1239 .filter_map(|&(_, annotation)| match annotation.annotation_type {
1240 AnnotationType::MultilineStart(p) | AnnotationType::MultilineEnd(p) => {
1241 let style = if annotation.is_primary {
1244 Style::LabelSecondary
1250 .collect::<Vec<_>>()
1253 fn get_multispan_max_line_num(&mut self, msp: &MultiSpan) -> usize {
1254 let Some(ref sm) = self.sm else {
1259 for primary_span in msp.primary_spans() {
1260 if !primary_span.is_dummy() {
1261 let hi = sm.lookup_char_pos(primary_span.hi());
1262 max = (hi.line).max(max);
1265 if !self.short_message {
1266 for span_label in msp.span_labels() {
1267 if !span_label.span.is_dummy() {
1268 let hi = sm.lookup_char_pos(span_label.span.hi());
1269 max = (hi.line).max(max);
1277 fn get_max_line_num(&mut self, span: &MultiSpan, children: &[SubDiagnostic]) -> usize {
1278 let primary = self.get_multispan_max_line_num(span);
1281 .map(|sub| self.get_multispan_max_line_num(&sub.span))
1287 /// Adds a left margin to every line but the first, given a padding length and the label being
1288 /// displayed, keeping the provided highlighting.
1291 buffer: &mut StyledBuffer,
1292 msg: &[(DiagnosticMessage, Style)],
1293 args: &FluentArgs<'_>,
1296 override_style: Option<Style>,
1298 // The extra 5 ` ` is padding that's always needed to align to the `note: `:
1301 // --> file.rs:13:20
1306 // = note: multiline
1311 // | | length of label
1313 // `max_line_num_len`
1314 let padding = " ".repeat(padding + label.len() + 5);
1316 /// Returns `override` if it is present and `style` is `NoStyle` or `style` otherwise
1317 fn style_or_override(style: Style, override_: Option<Style>) -> Style {
1318 match (style, override_) {
1319 (Style::NoStyle, Some(override_)) => override_,
1324 let mut line_number = 0;
1326 // Provided the following diagnostic message:
1330 // ("highlighted multiline\nstring to\nsee how it ", Style::NoStyle),
1331 // ("looks", Style::Highlight),
1332 // ("with\nvery ", Style::NoStyle),
1333 // ("weird", Style::Highlight),
1334 // (" formats\n", Style::NoStyle),
1335 // ("see?", Style::Highlight),
1338 // the expected output on a note is (* surround the highlighted text)
1340 // = note: highlighted multiline
1342 // see how it *looks* with
1343 // very *weird* formats
1345 for &(ref text, ref style) in msg.iter() {
1346 let text = self.translate_message(text, args);
1347 let lines = text.split('\n').collect::<Vec<_>>();
1348 if lines.len() > 1 {
1349 for (i, line) in lines.iter().enumerate() {
1352 buffer.append(line_number, &padding, Style::NoStyle);
1354 buffer.append(line_number, line, style_or_override(*style, override_style));
1357 buffer.append(line_number, &text, style_or_override(*style, override_style));
1362 fn emit_message_default(
1365 msg: &[(DiagnosticMessage, Style)],
1366 args: &FluentArgs<'_>,
1367 code: &Option<DiagnosticId>,
1369 max_line_num_len: usize,
1371 ) -> io::Result<()> {
1372 let mut buffer = StyledBuffer::new();
1374 if !msp.has_primary_spans() && !msp.has_span_labels() && is_secondary && !self.short_message
1376 // This is a secondary message with no span info
1377 for _ in 0..max_line_num_len {
1378 buffer.prepend(0, " ", Style::NoStyle);
1380 draw_note_separator(&mut buffer, 0, max_line_num_len + 1);
1381 if *level != Level::FailureNote {
1382 buffer.append(0, level.to_str(), Style::MainHeaderMsg);
1383 buffer.append(0, ": ", Style::NoStyle);
1385 self.msg_to_buffer(&mut buffer, msg, args, max_line_num_len, "note", None);
1387 let mut label_width = 0;
1388 // The failure note level itself does not provide any useful diagnostic information
1389 if *level != Level::FailureNote {
1390 buffer.append(0, level.to_str(), Style::Level(*level));
1391 label_width += level.to_str().len();
1393 // only render error codes, not lint codes
1394 if let Some(DiagnosticId::Error(ref code)) = *code {
1395 buffer.append(0, "[", Style::Level(*level));
1396 buffer.append(0, &code, Style::Level(*level));
1397 buffer.append(0, "]", Style::Level(*level));
1398 label_width += 2 + code.len();
1400 let header_style = if is_secondary { Style::HeaderMsg } else { Style::MainHeaderMsg };
1401 if *level != Level::FailureNote {
1402 buffer.append(0, ": ", header_style);
1405 for &(ref text, _) in msg.iter() {
1406 let text = self.translate_message(text, args);
1407 // Account for newlines to align output to its label.
1408 for (line, text) in normalize_whitespace(&text).lines().enumerate() {
1413 if line == 0 { String::new() } else { " ".repeat(label_width) },
1422 let mut annotated_files = FileWithAnnotatedLines::collect_annotations(self, args, msp);
1424 // Make sure our primary file comes first
1425 let (primary_lo, sm) = if let (Some(sm), Some(ref primary_span)) =
1426 (self.sm.as_ref(), msp.primary_span().as_ref())
1428 if !primary_span.is_dummy() {
1429 (sm.lookup_char_pos(primary_span.lo()), sm)
1431 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1435 // If we don't have span information, emit and exit
1436 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1440 annotated_files.binary_search_by(|x| x.file.name.cmp(&primary_lo.file.name))
1442 annotated_files.swap(0, pos);
1445 // Print out the annotate source lines that correspond with the error
1446 for annotated_file in annotated_files {
1447 // we can't annotate anything if the source is unavailable.
1448 if !sm.ensure_source_file_source_present(annotated_file.file.clone()) {
1452 // print out the span location and spacer before we print the annotated source
1453 // to do this, we need to know if this span will be primary
1454 let is_primary = primary_lo.file.name == annotated_file.file.name;
1456 let loc = primary_lo.clone();
1457 if !self.short_message {
1458 // remember where we are in the output buffer for easy reference
1459 let buffer_msg_line_offset = buffer.num_lines();
1461 buffer.prepend(buffer_msg_line_offset, "--> ", Style::LineNumber);
1463 buffer_msg_line_offset,
1466 sm.filename_for_diagnostics(&loc.file.name),
1467 sm.doctest_offset_line(&loc.file.name, loc.line),
1470 Style::LineAndColumn,
1472 for _ in 0..max_line_num_len {
1473 buffer.prepend(buffer_msg_line_offset, " ", Style::NoStyle);
1480 sm.filename_for_diagnostics(&loc.file.name),
1481 sm.doctest_offset_line(&loc.file.name, loc.line),
1484 Style::LineAndColumn,
1487 } else if !self.short_message {
1488 // remember where we are in the output buffer for easy reference
1489 let buffer_msg_line_offset = buffer.num_lines();
1492 draw_col_separator_no_space(
1494 buffer_msg_line_offset,
1495 max_line_num_len + 1,
1498 // Then, the secondary file indicator
1499 buffer.prepend(buffer_msg_line_offset + 1, "::: ", Style::LineNumber);
1500 let loc = if let Some(first_line) = annotated_file.lines.first() {
1501 let col = if let Some(first_annotation) = first_line.annotations.first() {
1502 format!(":{}", first_annotation.start_col + 1)
1508 sm.filename_for_diagnostics(&annotated_file.file.name),
1509 sm.doctest_offset_line(&annotated_file.file.name, first_line.line_index),
1513 format!("{}", sm.filename_for_diagnostics(&annotated_file.file.name))
1515 buffer.append(buffer_msg_line_offset + 1, &loc, Style::LineAndColumn);
1516 for _ in 0..max_line_num_len {
1517 buffer.prepend(buffer_msg_line_offset + 1, " ", Style::NoStyle);
1521 if !self.short_message {
1522 // Put in the spacer between the location and annotated source
1523 let buffer_msg_line_offset = buffer.num_lines();
1524 draw_col_separator_no_space(
1526 buffer_msg_line_offset,
1527 max_line_num_len + 1,
1530 // Contains the vertical lines' positions for active multiline annotations
1531 let mut multilines = FxHashMap::default();
1533 // Get the left-side margin to remove it
1534 let mut whitespace_margin = usize::MAX;
1535 for line_idx in 0..annotated_file.lines.len() {
1536 let file = annotated_file.file.clone();
1537 let line = &annotated_file.lines[line_idx];
1538 if let Some(source_string) = file.get_line(line.line_index - 1) {
1539 let leading_whitespace = source_string
1541 .take_while(|c| c.is_whitespace())
1544 // Tabs are displayed as 4 spaces
1550 if source_string.chars().any(|c| !c.is_whitespace()) {
1551 whitespace_margin = min(whitespace_margin, leading_whitespace);
1555 if whitespace_margin == usize::MAX {
1556 whitespace_margin = 0;
1559 // Left-most column any visible span points at.
1560 let mut span_left_margin = usize::MAX;
1561 for line in &annotated_file.lines {
1562 for ann in &line.annotations {
1563 span_left_margin = min(span_left_margin, ann.start_col);
1564 span_left_margin = min(span_left_margin, ann.end_col);
1567 if span_left_margin == usize::MAX {
1568 span_left_margin = 0;
1571 // Right-most column any visible span points at.
1572 let mut span_right_margin = 0;
1573 let mut label_right_margin = 0;
1574 let mut max_line_len = 0;
1575 for line in &annotated_file.lines {
1578 annotated_file.file.get_line(line.line_index - 1).map_or(0, |s| s.len()),
1580 for ann in &line.annotations {
1581 span_right_margin = max(span_right_margin, ann.start_col);
1582 span_right_margin = max(span_right_margin, ann.end_col);
1583 // FIXME: account for labels not in the same line
1584 let label_right = ann.label.as_ref().map_or(0, |l| l.len() + 1);
1585 label_right_margin = max(label_right_margin, ann.end_col + label_right);
1589 let width_offset = 3 + max_line_num_len;
1590 let code_offset = if annotated_file.multiline_depth == 0 {
1593 width_offset + annotated_file.multiline_depth + 1
1596 let column_width = if let Some(width) = self.terminal_width {
1597 width.saturating_sub(code_offset)
1598 } else if self.ui_testing {
1599 DEFAULT_COLUMN_WIDTH
1601 termize::dimensions()
1602 .map(|(w, _)| w.saturating_sub(code_offset))
1603 .unwrap_or(DEFAULT_COLUMN_WIDTH)
1606 let margin = Margin::new(
1615 // Next, output the annotate source for this file
1616 for line_idx in 0..annotated_file.lines.len() {
1617 let previous_buffer_line = buffer.num_lines();
1619 let depths = self.render_source_line(
1621 annotated_file.file.clone(),
1622 &annotated_file.lines[line_idx],
1628 let mut to_add = FxHashMap::default();
1630 for (depth, style) in depths {
1631 if multilines.remove(&depth).is_none() {
1632 to_add.insert(depth, style);
1636 // Set the multiline annotation vertical lines to the left of
1637 // the code in this line.
1638 for (depth, style) in &multilines {
1639 for line in previous_buffer_line..buffer.num_lines() {
1640 draw_multiline_line(&mut buffer, line, width_offset, *depth, *style);
1643 // check to see if we need to print out or elide lines that come between
1644 // this annotated line and the next one.
1645 if line_idx < (annotated_file.lines.len() - 1) {
1646 let line_idx_delta = annotated_file.lines[line_idx + 1].line_index
1647 - annotated_file.lines[line_idx].line_index;
1648 if line_idx_delta > 2 {
1649 let last_buffer_line_num = buffer.num_lines();
1650 buffer.puts(last_buffer_line_num, 0, "...", Style::LineNumber);
1652 // Set the multiline annotation vertical lines on `...` bridging line.
1653 for (depth, style) in &multilines {
1654 draw_multiline_line(
1656 last_buffer_line_num,
1662 } else if line_idx_delta == 2 {
1663 let unannotated_line = annotated_file
1665 .get_line(annotated_file.lines[line_idx].line_index)
1666 .unwrap_or_else(|| Cow::from(""));
1668 let last_buffer_line_num = buffer.num_lines();
1672 &normalize_whitespace(&unannotated_line),
1673 annotated_file.lines[line_idx + 1].line_index - 1,
1674 last_buffer_line_num,
1680 for (depth, style) in &multilines {
1681 draw_multiline_line(
1683 last_buffer_line_num,
1692 multilines.extend(&to_add);
1697 // final step: take our styled buffer, render it, then output it
1698 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1703 fn emit_suggestion_default(
1705 suggestion: &CodeSuggestion,
1706 args: &FluentArgs<'_>,
1708 max_line_num_len: usize,
1709 ) -> io::Result<()> {
1710 let Some(ref sm) = self.sm else {
1714 // Render the replacements for each suggestion
1715 let suggestions = suggestion.splice_lines(&**sm);
1716 debug!("emit_suggestion_default: suggestions={:?}", suggestions);
1718 if suggestions.is_empty() {
1719 // Suggestions coming from macros can have malformed spans. This is a heavy handed
1720 // approach to avoid ICEs by ignoring the suggestion outright.
1724 let mut buffer = StyledBuffer::new();
1726 // Render the suggestion message
1727 buffer.append(0, level.to_str(), Style::Level(*level));
1728 buffer.append(0, ": ", Style::HeaderMsg);
1732 &[(suggestion.msg.to_owned(), Style::NoStyle)],
1736 Some(Style::HeaderMsg),
1739 let mut row_num = 2;
1740 draw_col_separator_no_space(&mut buffer, 1, max_line_num_len + 1);
1741 let mut notice_capitalization = false;
1742 for (complete, parts, highlights, only_capitalization) in
1743 suggestions.iter().take(MAX_SUGGESTIONS)
1745 notice_capitalization |= only_capitalization;
1747 let has_deletion = parts.iter().any(|p| p.is_deletion());
1748 let is_multiline = complete.lines().count() > 1;
1750 enum DisplaySuggestion {
1756 let show_code_change = if has_deletion && !is_multiline {
1757 DisplaySuggestion::Diff
1758 } else if (parts.len() != 1 || parts[0].snippet.trim() != complete.trim())
1761 DisplaySuggestion::Underline
1763 DisplaySuggestion::None
1766 if let DisplaySuggestion::Diff = show_code_change {
1771 .span_to_lines(parts[0].span)
1772 .expect("span_to_lines failed when emitting suggestion");
1774 assert!(!file_lines.lines.is_empty() || parts[0].span.is_dummy());
1776 let line_start = sm.lookup_char_pos(parts[0].span.lo()).line;
1777 draw_col_separator_no_space(&mut buffer, 1, max_line_num_len + 1);
1778 let mut lines = complete.lines();
1779 if lines.clone().next().is_none() {
1780 // Account for a suggestion to completely remove a line(s) with whitespace (#94192).
1781 let line_end = sm.lookup_char_pos(parts[0].span.hi()).line;
1782 for line in line_start..=line_end {
1784 row_num - 1 + line - line_start,
1786 &self.maybe_anonymized(line),
1790 row_num - 1 + line - line_start,
1791 max_line_num_len + 1,
1796 row_num - 1 + line - line_start,
1797 max_line_num_len + 3,
1798 &normalize_whitespace(&*file_lines.file.get_line(line - 1).unwrap()),
1802 row_num += line_end - line_start;
1804 for (line_pos, (line, highlight_parts)) in
1805 lines.by_ref().zip(highlights).take(MAX_SUGGESTION_HIGHLIGHT_LINES).enumerate()
1807 // Print the span column to avoid confusion
1811 &self.maybe_anonymized(line_start + line_pos),
1814 if let DisplaySuggestion::Diff = show_code_change {
1815 // Add the line number for both addition and removal to drive the point home.
1817 // N - fn foo<A: T>(bar: A) {
1818 // N + fn foo(bar: impl T) {
1822 &self.maybe_anonymized(line_start + line_pos),
1825 buffer.puts(row_num - 1, max_line_num_len + 1, "- ", Style::Removal);
1828 max_line_num_len + 3,
1829 &normalize_whitespace(
1832 .get_line(file_lines.lines[line_pos].line_index)
1837 buffer.puts(row_num, max_line_num_len + 1, "+ ", Style::Addition);
1838 } else if is_multiline {
1839 match &highlight_parts[..] {
1840 [SubstitutionHighlight { start: 0, end }] if *end == line.len() => {
1841 buffer.puts(row_num, max_line_num_len + 1, "+ ", Style::Addition);
1844 draw_col_separator(&mut buffer, row_num, max_line_num_len + 1);
1847 buffer.puts(row_num, max_line_num_len + 1, "~ ", Style::Addition);
1851 draw_col_separator(&mut buffer, row_num, max_line_num_len + 1);
1854 // print the suggestion
1855 buffer.append(row_num, &normalize_whitespace(line), Style::NoStyle);
1857 // Colorize addition/replacements with green.
1858 for &SubstitutionHighlight { start, end } in highlight_parts {
1859 // Account for tabs when highlighting (#87972).
1860 let tabs: usize = line
1863 .map(|ch| match ch {
1868 buffer.set_style_range(
1870 max_line_num_len + 3 + start + tabs,
1871 max_line_num_len + 3 + end + tabs,
1879 // This offset and the ones below need to be signed to account for replacement code
1880 // that is shorter than the original code.
1881 let mut offsets: Vec<(usize, isize)> = Vec::new();
1882 // Only show an underline in the suggestions if the suggestion is not the
1883 // entirety of the code being shown and the displayed code is not multiline.
1884 if let DisplaySuggestion::Diff | DisplaySuggestion::Underline = show_code_change {
1885 draw_col_separator(&mut buffer, row_num, max_line_num_len + 1);
1887 let span_start_pos = sm.lookup_char_pos(part.span.lo()).col_display;
1888 let span_end_pos = sm.lookup_char_pos(part.span.hi()).col_display;
1890 // Do not underline the leading...
1891 let start = part.snippet.len().saturating_sub(part.snippet.trim_start().len());
1892 // ...or trailing spaces. Account for substitutions containing unicode
1894 let sub_len: usize = part
1898 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
1901 let offset: isize = offsets
1904 |(start, v)| if span_start_pos <= *start { None } else { Some(v) },
1907 let underline_start = (span_start_pos + start) as isize + offset;
1908 let underline_end = (span_start_pos + start + sub_len) as isize + offset;
1909 assert!(underline_start >= 0 && underline_end >= 0);
1910 let padding: usize = max_line_num_len + 3;
1911 for p in underline_start..underline_end {
1912 if let DisplaySuggestion::Underline = show_code_change {
1913 // If this is a replacement, underline with `^`, if this is an addition
1914 // underline with `+`.
1917 (padding as isize + p) as usize,
1918 if part.is_addition(&sm) { '+' } else { '~' },
1923 if let DisplaySuggestion::Diff = show_code_change {
1924 // Colorize removal with red in diff format.
1925 buffer.set_style_range(
1927 (padding as isize + span_start_pos as isize) as usize,
1928 (padding as isize + span_end_pos as isize) as usize,
1934 // length of the code after substitution
1935 let full_sub_len = part
1938 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
1939 .sum::<usize>() as isize;
1941 // length of the code to be substituted
1942 let snippet_len = span_end_pos as isize - span_start_pos as isize;
1943 // For multiple substitutions, use the position *after* the previous
1944 // substitutions have happened, only when further substitutions are
1945 // located strictly after.
1946 offsets.push((span_end_pos, full_sub_len - snippet_len));
1951 // if we elided some lines, add an ellipsis
1952 if lines.next().is_some() {
1953 buffer.puts(row_num, max_line_num_len - 1, "...", Style::LineNumber);
1954 } else if let DisplaySuggestion::None = show_code_change {
1955 draw_col_separator_no_space(&mut buffer, row_num, max_line_num_len + 1);
1959 if suggestions.len() > MAX_SUGGESTIONS {
1960 let others = suggestions.len() - MAX_SUGGESTIONS;
1961 let msg = format!("and {} other candidate{}", others, pluralize!(others));
1962 buffer.puts(row_num, max_line_num_len + 3, &msg, Style::NoStyle);
1963 } else if notice_capitalization {
1964 let msg = "notice the capitalization difference";
1965 buffer.puts(row_num, max_line_num_len + 3, &msg, Style::NoStyle);
1967 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1971 fn emit_messages_default(
1974 message: &[(DiagnosticMessage, Style)],
1975 args: &FluentArgs<'_>,
1976 code: &Option<DiagnosticId>,
1978 children: &[SubDiagnostic],
1979 suggestions: &[CodeSuggestion],
1981 let max_line_num_len = if self.ui_testing {
1982 ANONYMIZED_LINE_NUM.len()
1984 let n = self.get_max_line_num(span, children);
1985 num_decimal_digits(n)
1988 match self.emit_message_default(span, message, args, code, level, max_line_num_len, false) {
1990 if !children.is_empty()
1991 || suggestions.iter().any(|s| s.style != SuggestionStyle::CompletelyHidden)
1993 let mut buffer = StyledBuffer::new();
1994 if !self.short_message {
1995 draw_col_separator_no_space(&mut buffer, 0, max_line_num_len + 1);
1997 if let Err(e) = emit_to_destination(
2003 panic!("failed to emit error: {}", e)
2006 if !self.short_message {
2007 for child in children {
2008 let span = child.render_span.as_ref().unwrap_or(&child.span);
2009 if let Err(err) = self.emit_message_default(
2018 panic!("failed to emit error: {}", err);
2021 for sugg in suggestions {
2022 if sugg.style == SuggestionStyle::CompletelyHidden {
2023 // do not display this suggestion, it is meant only for tools
2024 } else if sugg.style == SuggestionStyle::HideCodeAlways {
2025 if let Err(e) = self.emit_message_default(
2027 &[(sugg.msg.to_owned(), Style::HeaderMsg)],
2034 panic!("failed to emit error: {}", e);
2036 } else if let Err(e) =
2037 self.emit_suggestion_default(sugg, args, &Level::Help, max_line_num_len)
2039 panic!("failed to emit error: {}", e);
2044 Err(e) => panic!("failed to emit error: {}", e),
2047 let mut dst = self.dst.writable();
2048 match writeln!(dst) {
2049 Err(e) => panic!("failed to emit error: {}", e),
2051 if let Err(e) = dst.flush() {
2052 panic!("failed to emit error: {}", e)
2059 impl FileWithAnnotatedLines {
2060 /// Preprocess all the annotations so that they are grouped by file and by line number
2061 /// This helps us quickly iterate over the whole message (including secondary file spans)
2062 pub fn collect_annotations(
2063 emitter: &dyn Emitter,
2064 args: &FluentArgs<'_>,
2066 ) -> Vec<FileWithAnnotatedLines> {
2067 fn add_annotation_to_file(
2068 file_vec: &mut Vec<FileWithAnnotatedLines>,
2069 file: Lrc<SourceFile>,
2073 for slot in file_vec.iter_mut() {
2074 // Look through each of our files for the one we're adding to
2075 if slot.file.name == file.name {
2076 // See if we already have a line for it
2077 for line_slot in &mut slot.lines {
2078 if line_slot.line_index == line_index {
2079 line_slot.annotations.push(ann);
2083 // We don't have a line yet, create one
2084 slot.lines.push(Line { line_index, annotations: vec![ann] });
2089 // This is the first time we're seeing the file
2090 file_vec.push(FileWithAnnotatedLines {
2092 lines: vec![Line { line_index, annotations: vec![ann] }],
2097 let mut output = vec![];
2098 let mut multiline_annotations = vec![];
2100 if let Some(ref sm) = emitter.source_map() {
2101 for span_label in msp.span_labels() {
2102 if span_label.span.is_dummy() {
2106 let lo = sm.lookup_char_pos(span_label.span.lo());
2107 let mut hi = sm.lookup_char_pos(span_label.span.hi());
2109 // Watch out for "empty spans". If we get a span like 6..6, we
2110 // want to just display a `^` at 6, so convert that to
2111 // 6..7. This is degenerate input, but it's best to degrade
2112 // gracefully -- and the parser likes to supply a span like
2113 // that for EOF, in particular.
2115 if lo.col_display == hi.col_display && lo.line == hi.line {
2116 hi.col_display += 1;
2119 if lo.line != hi.line {
2120 let ml = MultilineAnnotation {
2122 line_start: lo.line,
2124 start_col: lo.col_display,
2125 end_col: hi.col_display,
2126 is_primary: span_label.is_primary,
2130 .map(|m| emitter.translate_message(m, args).to_string()),
2131 overlaps_exactly: false,
2133 multiline_annotations.push((lo.file, ml));
2135 let ann = Annotation {
2136 start_col: lo.col_display,
2137 end_col: hi.col_display,
2138 is_primary: span_label.is_primary,
2142 .map(|m| emitter.translate_message(m, args).to_string()),
2143 annotation_type: AnnotationType::Singleline,
2145 add_annotation_to_file(&mut output, lo.file, lo.line, ann);
2150 // Find overlapping multiline annotations, put them at different depths
2151 multiline_annotations.sort_by_key(|&(_, ref ml)| (ml.line_start, ml.line_end));
2152 for (_, ann) in multiline_annotations.clone() {
2153 for (_, a) in multiline_annotations.iter_mut() {
2154 // Move all other multiline annotations overlapping with this one
2155 // one level to the right.
2156 if !(ann.same_span(a))
2157 && num_overlap(ann.line_start, ann.line_end, a.line_start, a.line_end, true)
2160 } else if ann.same_span(a) && &ann != a {
2161 a.overlaps_exactly = true;
2168 let mut max_depth = 0; // max overlapping multiline spans
2169 for (file, ann) in multiline_annotations {
2170 max_depth = max(max_depth, ann.depth);
2171 let mut end_ann = ann.as_end();
2172 if !ann.overlaps_exactly {
2173 // avoid output like
2195 add_annotation_to_file(&mut output, file.clone(), ann.line_start, ann.as_start());
2196 // 4 is the minimum vertical length of a multiline span when presented: two lines
2197 // of code and two lines of underline. This is not true for the special case where
2198 // the beginning doesn't have an underline, but the current logic seems to be
2199 // working correctly.
2200 let middle = min(ann.line_start + 4, ann.line_end);
2201 for line in ann.line_start + 1..middle {
2202 // Every `|` that joins the beginning of the span (`___^`) to the end (`|__^`).
2203 add_annotation_to_file(&mut output, file.clone(), line, ann.as_line());
2205 let line_end = ann.line_end - 1;
2206 if middle < line_end {
2207 add_annotation_to_file(&mut output, file.clone(), line_end, ann.as_line());
2210 end_ann.annotation_type = AnnotationType::Singleline;
2212 add_annotation_to_file(&mut output, file, ann.line_end, end_ann);
2214 for file_vec in output.iter_mut() {
2215 file_vec.multiline_depth = max_depth;
2221 // instead of taking the String length or dividing by 10 while > 0, we multiply a limit by 10 until
2222 // we're higher. If the loop isn't exited by the `return`, the last multiplication will wrap, which
2223 // is OK, because while we cannot fit a higher power of 10 in a usize, the loop will end anyway.
2224 // This is also why we need the max number of decimal digits within a `usize`.
2225 fn num_decimal_digits(num: usize) -> usize {
2226 #[cfg(target_pointer_width = "64")]
2227 const MAX_DIGITS: usize = 20;
2229 #[cfg(target_pointer_width = "32")]
2230 const MAX_DIGITS: usize = 10;
2232 #[cfg(target_pointer_width = "16")]
2233 const MAX_DIGITS: usize = 5;
2236 for num_digits in 1..MAX_DIGITS {
2240 lim = lim.wrapping_mul(10);
2245 // We replace some characters so the CLI output is always consistent and underlines aligned.
2246 const OUTPUT_REPLACEMENTS: &[(char, &str)] = &[
2247 ('\t', " "), // We do our own tab replacement
2248 ('\u{200D}', ""), // Replace ZWJ with nothing for consistent terminal output of grapheme clusters.
2249 ('\u{202A}', ""), // The following unicode text flow control characters are inconsistently
2250 ('\u{202B}', ""), // supported across CLIs and can cause confusion due to the bytes on disk
2251 ('\u{202D}', ""), // not corresponding to the visible source code, so we replace them always.
2260 fn normalize_whitespace(str: &str) -> String {
2261 let mut s = str.to_string();
2262 for (c, replacement) in OUTPUT_REPLACEMENTS {
2263 s = s.replace(*c, replacement);
2268 fn draw_col_separator(buffer: &mut StyledBuffer, line: usize, col: usize) {
2269 buffer.puts(line, col, "| ", Style::LineNumber);
2272 fn draw_col_separator_no_space(buffer: &mut StyledBuffer, line: usize, col: usize) {
2273 draw_col_separator_no_space_with_style(buffer, line, col, Style::LineNumber);
2276 fn draw_col_separator_no_space_with_style(
2277 buffer: &mut StyledBuffer,
2282 buffer.putc(line, col, '|', style);
2286 buffer: &mut StyledBuffer,
2293 for col in col_from..col_to {
2294 buffer.putc(line, col, symbol, style);
2298 fn draw_note_separator(buffer: &mut StyledBuffer, line: usize, col: usize) {
2299 buffer.puts(line, col, "= ", Style::LineNumber);
2302 fn draw_multiline_line(
2303 buffer: &mut StyledBuffer,
2309 buffer.putc(line, offset + depth - 1, '|', style);
2319 let extra = if inclusive { 1 } else { 0 };
2320 (b_start..b_end + extra).contains(&a_start) || (a_start..a_end + extra).contains(&b_start)
2322 fn overlaps(a1: &Annotation, a2: &Annotation, padding: usize) -> bool {
2323 num_overlap(a1.start_col, a1.end_col + padding, a2.start_col, a2.end_col, false)
2326 fn emit_to_destination(
2327 rendered_buffer: &[Vec<StyledString>],
2329 dst: &mut Destination,
2330 short_message: bool,
2331 ) -> io::Result<()> {
2334 let mut dst = dst.writable();
2336 // In order to prevent error message interleaving, where multiple error lines get intermixed
2337 // when multiple compiler processes error simultaneously, we emit errors with additional
2340 // On Unix systems, we write into a buffered terminal rather than directly to a terminal. When
2341 // the .flush() is called we take the buffer created from the buffered writes and write it at
2342 // one shot. Because the Unix systems use ANSI for the colors, which is a text-based styling
2343 // scheme, this buffered approach works and maintains the styling.
2345 // On Windows, styling happens through calls to a terminal API. This prevents us from using the
2346 // same buffering approach. Instead, we use a global Windows mutex, which we acquire long
2347 // enough to output the full error message, then we release.
2348 let _buffer_lock = lock::acquire_global_lock("rustc_errors");
2349 for (pos, line) in rendered_buffer.iter().enumerate() {
2351 dst.apply_style(*lvl, part.style)?;
2352 write!(dst, "{}", part.text)?;
2355 if !short_message && (!lvl.is_failure_note() || pos != rendered_buffer.len() - 1) {
2363 pub enum Destination {
2364 Terminal(StandardStream),
2365 Buffered(BufferWriter),
2366 // The bool denotes whether we should be emitting ansi color codes or not
2367 Raw(Box<(dyn Write + Send)>, bool),
2370 pub enum WritableDst<'a> {
2371 Terminal(&'a mut StandardStream),
2372 Buffered(&'a mut BufferWriter, Buffer),
2373 Raw(&'a mut (dyn Write + Send)),
2374 ColoredRaw(Ansi<&'a mut (dyn Write + Send)>),
2378 fn from_stderr(color: ColorConfig) -> Destination {
2379 let choice = color.to_color_choice();
2380 // On Windows we'll be performing global synchronization on the entire
2381 // system for emitting rustc errors, so there's no need to buffer
2384 // On non-Windows we rely on the atomicity of `write` to ensure errors
2385 // don't get all jumbled up.
2387 Terminal(StandardStream::stderr(choice))
2389 Buffered(BufferWriter::stderr(choice))
2393 fn writable(&mut self) -> WritableDst<'_> {
2395 Destination::Terminal(ref mut t) => WritableDst::Terminal(t),
2396 Destination::Buffered(ref mut t) => {
2397 let buf = t.buffer();
2398 WritableDst::Buffered(t, buf)
2400 Destination::Raw(ref mut t, false) => WritableDst::Raw(t),
2401 Destination::Raw(ref mut t, true) => WritableDst::ColoredRaw(Ansi::new(t)),
2405 fn supports_color(&self) -> bool {
2407 Self::Terminal(ref stream) => stream.supports_color(),
2408 Self::Buffered(ref buffer) => buffer.buffer().supports_color(),
2409 Self::Raw(_, supports_color) => supports_color,
2414 impl<'a> WritableDst<'a> {
2415 fn apply_style(&mut self, lvl: Level, style: Style) -> io::Result<()> {
2416 let mut spec = ColorSpec::new();
2418 Style::Addition => {
2419 spec.set_fg(Some(Color::Green)).set_intense(true);
2422 spec.set_fg(Some(Color::Red)).set_intense(true);
2424 Style::LineAndColumn => {}
2425 Style::LineNumber => {
2426 spec.set_bold(true);
2427 spec.set_intense(true);
2429 spec.set_fg(Some(Color::Cyan));
2431 spec.set_fg(Some(Color::Blue));
2434 Style::Quotation => {}
2435 Style::MainHeaderMsg => {
2436 spec.set_bold(true);
2438 spec.set_intense(true).set_fg(Some(Color::White));
2441 Style::UnderlinePrimary | Style::LabelPrimary => {
2443 spec.set_bold(true);
2445 Style::UnderlineSecondary | Style::LabelSecondary => {
2446 spec.set_bold(true).set_intense(true);
2448 spec.set_fg(Some(Color::Cyan));
2450 spec.set_fg(Some(Color::Blue));
2453 Style::HeaderMsg | Style::NoStyle => {}
2454 Style::Level(lvl) => {
2456 spec.set_bold(true);
2458 Style::Highlight => {
2459 spec.set_bold(true);
2462 self.set_color(&spec)
2465 fn set_color(&mut self, color: &ColorSpec) -> io::Result<()> {
2467 WritableDst::Terminal(ref mut t) => t.set_color(color),
2468 WritableDst::Buffered(_, ref mut t) => t.set_color(color),
2469 WritableDst::ColoredRaw(ref mut t) => t.set_color(color),
2470 WritableDst::Raw(_) => Ok(()),
2474 fn reset(&mut self) -> io::Result<()> {
2476 WritableDst::Terminal(ref mut t) => t.reset(),
2477 WritableDst::Buffered(_, ref mut t) => t.reset(),
2478 WritableDst::ColoredRaw(ref mut t) => t.reset(),
2479 WritableDst::Raw(_) => Ok(()),
2484 impl<'a> Write for WritableDst<'a> {
2485 fn write(&mut self, bytes: &[u8]) -> io::Result<usize> {
2487 WritableDst::Terminal(ref mut t) => t.write(bytes),
2488 WritableDst::Buffered(_, ref mut buf) => buf.write(bytes),
2489 WritableDst::Raw(ref mut w) => w.write(bytes),
2490 WritableDst::ColoredRaw(ref mut t) => t.write(bytes),
2494 fn flush(&mut self) -> io::Result<()> {
2496 WritableDst::Terminal(ref mut t) => t.flush(),
2497 WritableDst::Buffered(_, ref mut buf) => buf.flush(),
2498 WritableDst::Raw(ref mut w) => w.flush(),
2499 WritableDst::ColoredRaw(ref mut w) => w.flush(),
2504 impl<'a> Drop for WritableDst<'a> {
2505 fn drop(&mut self) {
2506 if let WritableDst::Buffered(ref mut dst, ref mut buf) = self {
2507 drop(dst.print(buf));
2512 /// Whether the original and suggested code are visually similar enough to warrant extra wording.
2513 pub fn is_case_difference(sm: &SourceMap, suggested: &str, sp: Span) -> bool {
2514 // FIXME: this should probably be extended to also account for `FO0` → `FOO` and unicode.
2515 let found = match sm.span_to_snippet(sp) {
2516 Ok(snippet) => snippet,
2518 warn!(error = ?e, "Invalid span {:?}", sp);
2522 let ascii_confusables = &['c', 'f', 'i', 'k', 'o', 's', 'u', 'v', 'w', 'x', 'y', 'z'];
2523 // All the chars that differ in capitalization are confusable (above):
2524 let confusable = iter::zip(found.chars(), suggested.chars())
2525 .filter(|(f, s)| f != s)
2526 .all(|(f, s)| (ascii_confusables.contains(&f) || ascii_confusables.contains(&s)));
2527 confusable && found.to_lowercase() == suggested.to_lowercase()
2528 // FIXME: We sometimes suggest the same thing we already have, which is a
2529 // bug, but be defensive against that here.
2530 && found != suggested