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::{FileLines, 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, LazyFallbackBundle, Level, MultiSpan, SubDiagnostic, SubstitutionHighlight,
23 use rustc_lint_defs::pluralize;
25 use rustc_data_structures::fx::FxHashMap;
26 use rustc_data_structures::sync::Lrc;
27 use rustc_error_messages::FluentArgs;
28 use rustc_span::hygiene::{ExpnKind, MacroKind};
30 use std::cmp::{max, min, Reverse};
32 use std::io::prelude::*;
35 use termcolor::{Ansi, BufferWriter, ColorChoice, ColorSpec, StandardStream};
36 use termcolor::{Buffer, Color, WriteColor};
39 /// Default column width, used in tests and when terminal dimensions cannot be determined.
40 const DEFAULT_COLUMN_WIDTH: usize = 140;
42 /// Describes the way the content of the `rendered` field of the json output is generated
43 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
44 pub enum HumanReadableErrorType {
46 AnnotateSnippet(ColorConfig),
50 impl HumanReadableErrorType {
51 /// Returns a (`short`, `color`) tuple
52 pub fn unzip(self) -> (bool, ColorConfig) {
54 HumanReadableErrorType::Default(cc) => (false, cc),
55 HumanReadableErrorType::Short(cc) => (true, cc),
56 HumanReadableErrorType::AnnotateSnippet(cc) => (false, cc),
61 dst: Box<dyn Write + Send>,
62 source_map: Option<Lrc<SourceMap>>,
63 bundle: Option<Lrc<FluentBundle>>,
64 fallback_bundle: LazyFallbackBundle,
66 diagnostic_width: Option<usize>,
67 macro_backtrace: bool,
69 let (short, color_config) = self.unzip();
70 let color = color_config.suggests_using_colors();
85 #[derive(Clone, Copy, Debug)]
87 /// The available whitespace in the left that can be consumed when centering.
88 pub whitespace_left: usize,
89 /// The column of the beginning of left-most span.
91 /// The column of the end of right-most span.
92 pub span_right: usize,
93 /// The beginning of the line to be displayed.
94 pub computed_left: usize,
95 /// The end of the line to be displayed.
96 pub computed_right: usize,
97 /// The current width of the terminal. Uses value of `DEFAULT_COLUMN_WIDTH` constant by default
99 pub column_width: usize,
100 /// The end column of a span label, including the span. Doesn't account for labels not in the
101 /// same line as the span.
102 pub label_right: usize,
107 whitespace_left: usize,
114 // The 6 is padding to give a bit of room for `...` when displaying:
119 // 16 | ... fn foo(self) -> Self::Bar {
124 whitespace_left: whitespace_left.saturating_sub(6),
125 span_left: span_left.saturating_sub(6),
126 span_right: span_right + 6,
130 label_right: label_right + 6,
132 m.compute(max_line_len);
136 fn was_cut_left(&self) -> bool {
137 self.computed_left > 0
140 fn was_cut_right(&self, line_len: usize) -> bool {
142 if self.computed_right == self.span_right || self.computed_right == self.label_right {
143 // Account for the "..." padding given above. Otherwise we end up with code lines that
144 // do fit but end in "..." as if they were trimmed.
145 self.computed_right - 6
149 right < line_len && self.computed_left + self.column_width < line_len
152 fn compute(&mut self, max_line_len: usize) {
153 // When there's a lot of whitespace (>20), we want to trim it as it is useless.
154 self.computed_left = if self.whitespace_left > 20 {
155 self.whitespace_left - 16 // We want some padding.
159 // We want to show as much as possible, max_line_len is the right-most boundary for the
161 self.computed_right = max(max_line_len, self.computed_left);
163 if self.computed_right - self.computed_left > self.column_width {
164 // Trimming only whitespace isn't enough, let's get craftier.
165 if self.label_right - self.whitespace_left <= self.column_width {
166 // Attempt to fit the code window only trimming whitespace.
167 self.computed_left = self.whitespace_left;
168 self.computed_right = self.computed_left + self.column_width;
169 } else if self.label_right - self.span_left <= self.column_width {
170 // Attempt to fit the code window considering only the spans and labels.
171 let padding_left = (self.column_width - (self.label_right - self.span_left)) / 2;
172 self.computed_left = self.span_left.saturating_sub(padding_left);
173 self.computed_right = self.computed_left + self.column_width;
174 } else if self.span_right - self.span_left <= self.column_width {
175 // Attempt to fit the code window considering the spans and labels plus padding.
176 let padding_left = (self.column_width - (self.span_right - self.span_left)) / 5 * 2;
177 self.computed_left = self.span_left.saturating_sub(padding_left);
178 self.computed_right = self.computed_left + self.column_width;
180 // Mostly give up but still don't show the full line.
181 self.computed_left = self.span_left;
182 self.computed_right = self.span_right;
187 fn left(&self, line_len: usize) -> usize {
188 min(self.computed_left, line_len)
191 fn right(&self, line_len: usize) -> usize {
192 if line_len.saturating_sub(self.computed_left) <= self.column_width {
195 min(line_len, self.computed_right)
200 const ANONYMIZED_LINE_NUM: &str = "LL";
202 /// Emitter trait for emitting errors.
204 /// Emit a structured diagnostic.
205 fn emit_diagnostic(&mut self, diag: &Diagnostic);
207 /// Emit a notification that an artifact has been output.
208 /// This is currently only supported for the JSON format,
209 /// other formats can, and will, simply ignore it.
210 fn emit_artifact_notification(&mut self, _path: &Path, _artifact_type: &str) {}
212 fn emit_future_breakage_report(&mut self, _diags: Vec<Diagnostic>) {}
214 /// Emit list of unused externs
215 fn emit_unused_externs(
217 _lint_level: rustc_lint_defs::Level,
218 _unused_externs: &[&str],
222 /// Checks if should show explanations about "rustc --explain"
223 fn should_show_explain(&self) -> bool {
227 /// Checks if we can use colors in the current output stream.
228 fn supports_color(&self) -> bool {
232 fn source_map(&self) -> Option<&Lrc<SourceMap>>;
234 /// Return `FluentBundle` with localized diagnostics for the locale requested by the user. If no
235 /// language was requested by the user then this will be `None` and `fallback_fluent_bundle`
237 fn fluent_bundle(&self) -> Option<&Lrc<FluentBundle>>;
239 /// Return `FluentBundle` with localized diagnostics for the default locale of the compiler.
240 /// Used when the user has not requested a specific language or when a localized diagnostic is
241 /// unavailable for the requested locale.
242 fn fallback_fluent_bundle(&self) -> &FluentBundle;
244 /// Convert diagnostic arguments (a rustc internal type that exists to implement
245 /// `Encodable`/`Decodable`) into `FluentArgs` which is necessary to perform translation.
247 /// Typically performed once for each diagnostic at the start of `emit_diagnostic` and then
248 /// passed around as a reference thereafter.
249 fn to_fluent_args<'arg>(&self, args: &[DiagnosticArg<'arg>]) -> FluentArgs<'arg> {
250 FromIterator::from_iter(args.to_vec().drain(..))
253 /// Convert `DiagnosticMessage`s to a string, performing translation if necessary.
254 fn translate_messages(
256 messages: &[(DiagnosticMessage, Style)],
257 args: &FluentArgs<'_>,
260 messages.iter().map(|(m, _)| self.translate_message(m, args)).collect::<String>(),
264 /// Convert a `DiagnosticMessage` to a string, performing translation if necessary.
265 fn translate_message<'a>(
267 message: &'a DiagnosticMessage,
268 args: &'a FluentArgs<'_>,
270 trace!(?message, ?args);
271 let (identifier, attr) = match message {
272 DiagnosticMessage::Str(msg) => return Cow::Borrowed(&msg),
273 DiagnosticMessage::FluentIdentifier(identifier, attr) => (identifier, attr),
276 let bundle = match self.fluent_bundle() {
277 Some(bundle) if bundle.has_message(&identifier) => bundle,
278 _ => self.fallback_fluent_bundle(),
281 let message = bundle.get_message(&identifier).expect("missing diagnostic in fluent bundle");
282 let value = match attr {
284 if let Some(attr) = message.get_attribute(attr) {
287 panic!("missing attribute `{attr}` in fluent message `{identifier}`")
291 if let Some(value) = message.value() {
294 panic!("missing value in fluent message `{identifier}`")
299 let mut err = vec![];
300 let translated = bundle.format_pattern(value, Some(&args), &mut err);
301 trace!(?translated, ?err);
304 "identifier: {:?}, args: {:?}, errors: {:?}",
312 /// Formats the substitutions of the primary_span
314 /// There are a lot of conditions to this method, but in short:
316 /// * If the current `Diagnostic` has only one visible `CodeSuggestion`,
317 /// we format the `help` suggestion depending on the content of the
318 /// substitutions. In that case, we return the modified span only.
320 /// * If the current `Diagnostic` has multiple suggestions,
321 /// we return the original `primary_span` and the original suggestions.
322 fn primary_span_formatted<'a>(
324 diag: &'a Diagnostic,
325 fluent_args: &FluentArgs<'_>,
326 ) -> (MultiSpan, &'a [CodeSuggestion]) {
327 let mut primary_span = diag.span.clone();
328 let suggestions = diag.suggestions.as_ref().map_or(&[][..], |suggestions| &suggestions[..]);
329 if let Some((sugg, rest)) = suggestions.split_first() {
330 let msg = self.translate_message(&sugg.msg, fluent_args);
331 if rest.is_empty() &&
332 // ^ if there is only one suggestion
333 // don't display multi-suggestions as labels
334 sugg.substitutions.len() == 1 &&
335 // don't display multipart suggestions as labels
336 sugg.substitutions[0].parts.len() == 1 &&
337 // don't display long messages as labels
338 msg.split_whitespace().count() < 10 &&
339 // don't display multiline suggestions as labels
340 !sugg.substitutions[0].parts[0].snippet.contains('\n') &&
342 // when this style is set we want the suggestion to be a message, not inline
343 SuggestionStyle::HideCodeAlways,
344 // trivial suggestion for tooling's sake, never shown
345 SuggestionStyle::CompletelyHidden,
346 // subtle suggestion, never shown inline
347 SuggestionStyle::ShowAlways,
348 ].contains(&sugg.style)
350 let substitution = &sugg.substitutions[0].parts[0].snippet.trim();
351 let msg = if substitution.is_empty() || sugg.style.hide_inline() {
352 // This substitution is only removal OR we explicitly don't want to show the
353 // code inline (`hide_inline`). Therefore, we don't show the substitution.
354 format!("help: {}", &msg)
356 // Show the default suggestion text with the substitution
362 .map(|sm| is_case_difference(
365 sugg.substitutions[0].parts[0].span,
369 " (notice the capitalization)"
376 primary_span.push_span_label(sugg.substitutions[0].parts[0].span, msg);
378 // We return only the modified primary_span
381 // if there are multiple suggestions, print them all in full
382 // to be consistent. We could try to figure out if we can
383 // make one (or the first one) inline, but that would give
384 // undue importance to a semi-random suggestion
385 (primary_span, suggestions)
388 (primary_span, suggestions)
392 fn fix_multispans_in_extern_macros_and_render_macro_backtrace(
394 source_map: &Option<Lrc<SourceMap>>,
395 span: &mut MultiSpan,
396 children: &mut Vec<SubDiagnostic>,
400 // Check for spans in macros, before `fix_multispans_in_extern_macros`
401 // has a chance to replace them.
402 let has_macro_spans: Vec<_> = iter::once(&*span)
403 .chain(children.iter().map(|child| &child.span))
404 .flat_map(|span| span.primary_spans())
405 .flat_map(|sp| sp.macro_backtrace())
406 .filter_map(|expn_data| {
407 match expn_data.kind {
408 ExpnKind::Root => None,
410 // Skip past non-macro entries, just in case there
411 // are some which do actually involve macros.
412 ExpnKind::Inlined | ExpnKind::Desugaring(..) | ExpnKind::AstPass(..) => None,
414 ExpnKind::Macro(macro_kind, name) => Some((macro_kind, name)),
420 self.fix_multispans_in_extern_macros(source_map, span, children);
423 self.render_multispans_macro_backtrace(span, children, backtrace);
426 if let Some((macro_kind, name)) = has_macro_spans.first() {
427 // Mark the actual macro this originates from
428 let and_then = if let Some((macro_kind, last_name)) = has_macro_spans.last()
431 let descr = macro_kind.descr();
433 " which comes from the expansion of the {descr} `{last_name}`",
439 let descr = macro_kind.descr();
441 "this {level} originates in the {descr} `{name}`{and_then} \
442 (in Nightly builds, run with -Z macro-backtrace for more info)",
445 children.push(SubDiagnostic {
447 message: vec![(DiagnosticMessage::Str(msg), Style::NoStyle)],
448 span: MultiSpan::new(),
455 fn render_multispans_macro_backtrace(
457 span: &mut MultiSpan,
458 children: &mut Vec<SubDiagnostic>,
461 for span in iter::once(span).chain(children.iter_mut().map(|child| &mut child.span)) {
462 self.render_multispan_macro_backtrace(span, backtrace);
466 fn render_multispan_macro_backtrace(&self, span: &mut MultiSpan, always_backtrace: bool) {
467 let mut new_labels: Vec<(Span, String)> = vec![];
469 for &sp in span.primary_spans() {
474 // FIXME(eddyb) use `retain` on `macro_backtrace` to remove all the
475 // entries we don't want to print, to make sure the indices being
476 // printed are contiguous (or omitted if there's only one entry).
477 let macro_backtrace: Vec<_> = sp.macro_backtrace().collect();
478 for (i, trace) in macro_backtrace.iter().rev().enumerate() {
479 if trace.def_site.is_dummy() {
483 if always_backtrace && !matches!(trace.kind, ExpnKind::Inlined) {
487 "in this expansion of `{}`{}",
489 if macro_backtrace.len() > 1 {
490 // if macro_backtrace.len() == 1 it'll be
491 // pointed at by "in this macro invocation"
492 format!(" (#{})", i + 1)
500 // Don't add a label on the call site if the diagnostic itself
501 // already points to (a part of) that call site, as the label
502 // is meant for showing the relevant invocation when the actual
503 // diagnostic is pointing to some part of macro definition.
505 // This also handles the case where an external span got replaced
506 // with the call site span by `fix_multispans_in_extern_macros`.
508 // NB: `-Zmacro-backtrace` overrides this, for uniformity, as the
509 // "in this expansion of" label above is always added in that mode,
510 // and it needs an "in this macro invocation" label to match that.
511 let redundant_span = trace.call_site.contains(sp);
513 if !redundant_span || always_backtrace {
514 let msg: Cow<'static, _> = match trace.kind {
515 ExpnKind::Macro(MacroKind::Attr, _) => {
516 "this procedural macro expansion".into()
518 ExpnKind::Macro(MacroKind::Derive, _) => {
519 "this derive macro expansion".into()
521 ExpnKind::Macro(MacroKind::Bang, _) => "this macro invocation".into(),
522 ExpnKind::Inlined => "this inlined function call".into(),
523 ExpnKind::Root => "the crate root".into(),
524 ExpnKind::AstPass(kind) => kind.descr().into(),
525 ExpnKind::Desugaring(kind) => {
526 format!("this {} desugaring", kind.descr()).into()
534 if macro_backtrace.len() > 1 && always_backtrace {
535 // only specify order when the macro
536 // backtrace is multiple levels deep
537 format!(" (#{})", i + 1)
544 if !always_backtrace {
550 for (label_span, label_text) in new_labels {
551 span.push_span_label(label_span, label_text);
555 // This does a small "fix" for multispans by looking to see if it can find any that
556 // point directly at external macros. Since these are often difficult to read,
557 // this will change the span to point at the use site.
558 fn fix_multispans_in_extern_macros(
560 source_map: &Option<Lrc<SourceMap>>,
561 span: &mut MultiSpan,
562 children: &mut Vec<SubDiagnostic>,
564 let Some(source_map) = source_map else { return };
565 debug!("fix_multispans_in_extern_macros: before: span={:?} children={:?}", span, children);
566 self.fix_multispan_in_extern_macros(source_map, span);
567 for child in children.iter_mut() {
568 self.fix_multispan_in_extern_macros(source_map, &mut child.span);
570 debug!("fix_multispans_in_extern_macros: after: span={:?} children={:?}", span, children);
573 // This "fixes" MultiSpans that contain `Span`s pointing to locations inside of external macros.
574 // Since these locations are often difficult to read,
575 // we move these spans from the external macros to their corresponding use site.
576 fn fix_multispan_in_extern_macros(&self, source_map: &Lrc<SourceMap>, span: &mut MultiSpan) {
577 // First, find all the spans in external macros and point instead at their use site.
578 let replacements: Vec<(Span, Span)> = span
582 .chain(span.span_labels().iter().map(|sp_label| sp_label.span))
584 if !sp.is_dummy() && source_map.is_imported(sp) {
585 let maybe_callsite = sp.source_callsite();
586 if sp != maybe_callsite {
587 return Some((sp, maybe_callsite));
594 // After we have them, make sure we replace these 'bad' def sites with their use sites.
595 for (from, to) in replacements {
596 span.replace(from, to);
601 impl Emitter for EmitterWriter {
602 fn source_map(&self) -> Option<&Lrc<SourceMap>> {
606 fn fluent_bundle(&self) -> Option<&Lrc<FluentBundle>> {
607 self.fluent_bundle.as_ref()
610 fn fallback_fluent_bundle(&self) -> &FluentBundle {
611 &**self.fallback_bundle
614 fn emit_diagnostic(&mut self, diag: &Diagnostic) {
615 let fluent_args = self.to_fluent_args(diag.args());
617 let mut children = diag.children.clone();
618 let (mut primary_span, suggestions) = self.primary_span_formatted(&diag, &fluent_args);
619 debug!("emit_diagnostic: suggestions={:?}", suggestions);
621 self.fix_multispans_in_extern_macros_and_render_macro_backtrace(
626 self.macro_backtrace,
629 self.emit_messages_default(
640 fn should_show_explain(&self) -> bool {
644 fn supports_color(&self) -> bool {
645 self.dst.supports_color()
649 /// An emitter that does nothing when emitting a non-fatal diagnostic.
650 /// Fatal diagnostics are forwarded to `fatal_handler` to avoid silent
651 /// failures of rustc, as witnessed e.g. in issue #89358.
652 pub struct SilentEmitter {
653 pub fatal_handler: Handler,
654 pub fatal_note: Option<String>,
657 impl Emitter for SilentEmitter {
658 fn source_map(&self) -> Option<&Lrc<SourceMap>> {
662 fn fluent_bundle(&self) -> Option<&Lrc<FluentBundle>> {
666 fn fallback_fluent_bundle(&self) -> &FluentBundle {
667 panic!("silent emitter attempted to translate message")
670 fn emit_diagnostic(&mut self, d: &Diagnostic) {
671 if d.level == Level::Fatal {
672 let mut d = d.clone();
673 if let Some(ref note) = self.fatal_note {
676 self.fatal_handler.emit_diagnostic(&mut d);
681 /// Maximum number of suggestions to be shown
683 /// Arbitrary, but taken from trait import suggestion limit
684 pub const MAX_SUGGESTIONS: usize = 4;
686 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
687 pub enum ColorConfig {
694 fn to_color_choice(self) -> ColorChoice {
696 ColorConfig::Always => {
697 if atty::is(atty::Stream::Stderr) {
700 ColorChoice::AlwaysAnsi
703 ColorConfig::Never => ColorChoice::Never,
704 ColorConfig::Auto if atty::is(atty::Stream::Stderr) => ColorChoice::Auto,
705 ColorConfig::Auto => ColorChoice::Never,
708 fn suggests_using_colors(self) -> bool {
710 ColorConfig::Always | ColorConfig::Auto => true,
711 ColorConfig::Never => false,
716 /// Handles the writing of `HumanReadableErrorType::Default` and `HumanReadableErrorType::Short`
717 pub struct EmitterWriter {
719 sm: Option<Lrc<SourceMap>>,
720 fluent_bundle: Option<Lrc<FluentBundle>>,
721 fallback_bundle: LazyFallbackBundle,
725 diagnostic_width: Option<usize>,
727 macro_backtrace: bool,
731 pub struct FileWithAnnotatedLines {
732 pub file: Lrc<SourceFile>,
733 pub lines: Vec<Line>,
734 multiline_depth: usize,
739 color_config: ColorConfig,
740 source_map: Option<Lrc<SourceMap>>,
741 fluent_bundle: Option<Lrc<FluentBundle>>,
742 fallback_bundle: LazyFallbackBundle,
745 diagnostic_width: Option<usize>,
746 macro_backtrace: bool,
748 let dst = Destination::from_stderr(color_config);
763 dst: Box<dyn Write + Send>,
764 source_map: Option<Lrc<SourceMap>>,
765 fluent_bundle: Option<Lrc<FluentBundle>>,
766 fallback_bundle: LazyFallbackBundle,
770 diagnostic_width: Option<usize>,
771 macro_backtrace: bool,
774 dst: Raw(dst, colored),
786 pub fn ui_testing(mut self, ui_testing: bool) -> Self {
787 self.ui_testing = ui_testing;
791 fn maybe_anonymized(&self, line_num: usize) -> Cow<'static, str> {
793 Cow::Borrowed(ANONYMIZED_LINE_NUM)
795 Cow::Owned(line_num.to_string())
801 buffer: &mut StyledBuffer,
809 // Tabs are assumed to have been replaced by spaces in calling code.
810 debug_assert!(!source_string.contains('\t'));
811 let line_len = source_string.len();
812 // Create the source line we will highlight.
813 let left = margin.left(line_len);
814 let right = margin.right(line_len);
815 // On long lines, we strip the source line, accounting for unicode.
817 let code: String = source_string
821 // Make sure that the trimming on the right will fall within the terminal width.
822 // FIXME: `unicode_width` sometimes disagrees with terminals on how wide a `char` is.
823 // For now, just accept that sometimes the code line will be longer than desired.
824 let next = unicode_width::UnicodeWidthChar::width(*ch).unwrap_or(1);
825 if taken + next > right - left {
832 buffer.puts(line_offset, code_offset, &code, Style::Quotation);
833 if margin.was_cut_left() {
834 // We have stripped some code/whitespace from the beginning, make it clear.
835 buffer.puts(line_offset, code_offset, "...", Style::LineNumber);
837 if margin.was_cut_right(line_len) {
838 // We have stripped some code after the right-most span end, make it clear we did so.
839 buffer.puts(line_offset, code_offset + taken - 3, "...", Style::LineNumber);
841 buffer.puts(line_offset, 0, &self.maybe_anonymized(line_index), Style::LineNumber);
843 draw_col_separator_no_space(buffer, line_offset, width_offset - 2);
846 fn render_source_line(
848 buffer: &mut StyledBuffer,
849 file: Lrc<SourceFile>,
854 ) -> Vec<(usize, Style)> {
860 // | secondary span label
862 // ^^ ^ ^^^ ^^^^ ^^^ we don't care about code too far to the right of a span, we trim it
864 // | | | actual code found in your source code and the spans we use to mark it
865 // | | when there's too much wasted space to the left, trim it
866 // | vertical divider between the column number and the code
869 if line.line_index == 0 {
873 let source_string = match file.get_line(line.line_index - 1) {
874 Some(s) => normalize_whitespace(&*s),
875 None => return Vec::new(),
878 let line_offset = buffer.num_lines();
881 let left = margin.left(source_string.len());
883 // Account for unicode characters of width !=0 that were removed.
884 let left = source_string
887 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
900 // Special case when there's only one annotation involved, it is the start of a multiline
901 // span and there's no text at the beginning of the code line. Instead of doing the whole
910 // we simplify the output to:
916 if let [ann] = &line.annotations[..] {
917 if let AnnotationType::MultilineStart(depth) = ann.annotation_type {
918 if source_string.chars().take(ann.start_col).all(|c| c.is_whitespace()) {
919 let style = if ann.is_primary {
920 Style::UnderlinePrimary
922 Style::UnderlineSecondary
924 buffer.putc(line_offset, width_offset + depth - 1, '/', style);
925 return vec![(depth, style)];
930 // We want to display like this:
932 // vec.push(vec.pop().unwrap());
933 // --- ^^^ - previous borrow ends here
935 // | error occurs here
936 // previous borrow of `vec` occurs here
938 // But there are some weird edge cases to be aware of:
940 // vec.push(vec.pop().unwrap());
941 // -------- - previous borrow ends here
943 // |this makes no sense
944 // previous borrow of `vec` occurs here
946 // For this reason, we group the lines into "highlight lines"
947 // and "annotations lines", where the highlight lines have the `^`.
949 // Sort the annotations by (start, end col)
950 // The labels are reversed, sort and then reversed again.
951 // Consider a list of annotations (A1, A2, C1, C2, B1, B2) where
952 // the letter signifies the span. Here we are only sorting by the
953 // span and hence, the order of the elements with the same span will
954 // not change. On reversing the ordering (|a, b| but b.cmp(a)), you get
955 // (C1, C2, B1, B2, A1, A2). All the elements with the same span are
956 // still ordered first to last, but all the elements with different
957 // spans are ordered by their spans in last to first order. Last to
958 // first order is important, because the jiggly lines and | are on
959 // the left, so the rightmost span needs to be rendered first,
960 // otherwise the lines would end up needing to go over a message.
962 let mut annotations = line.annotations.clone();
963 annotations.sort_by_key(|a| Reverse(a.start_col));
965 // First, figure out where each label will be positioned.
967 // In the case where you have the following annotations:
969 // vec.push(vec.pop().unwrap());
970 // -------- - previous borrow ends here [C]
972 // |this makes no sense [B]
973 // previous borrow of `vec` occurs here [A]
975 // `annotations_position` will hold [(2, A), (1, B), (0, C)].
977 // We try, when possible, to stick the rightmost annotation at the end
978 // of the highlight line:
980 // vec.push(vec.pop().unwrap());
981 // --- --- - previous borrow ends here
983 // But sometimes that's not possible because one of the other
984 // annotations overlaps it. For example, from the test
985 // `span_overlap_label`, we have the following annotations
986 // (written on distinct lines for clarity):
992 // In this case, we can't stick the rightmost-most label on
993 // the highlight line, or we would get:
1000 // which is totally weird. Instead we want:
1008 // which is...less weird, at least. In fact, in general, if
1009 // the rightmost span overlaps with any other span, we should
1010 // use the "hang below" version, so we can at least make it
1011 // clear where the span *starts*. There's an exception for this
1012 // logic, when the labels do not have a message:
1027 let mut annotations_position = vec![];
1028 let mut line_len = 0;
1030 for (i, annotation) in annotations.iter().enumerate() {
1031 for (j, next) in annotations.iter().enumerate() {
1032 if overlaps(next, annotation, 0) // This label overlaps with another one and both
1033 && annotation.has_label() // take space (they have text and are not
1034 && j > i // multiline lines).
1036 // We're currently on the first line, move the label one line down
1038 // If we're overlapping with an un-labelled annotation with the same span
1039 // we can just merge them in the output
1040 if next.start_col == annotation.start_col
1041 && next.end_col == annotation.end_col
1042 && !next.has_label()
1047 // This annotation needs a new line in the output.
1052 annotations_position.push((p, annotation));
1053 for (j, next) in annotations.iter().enumerate() {
1055 let l = next.label.as_ref().map_or(0, |label| label.len() + 2);
1056 if (overlaps(next, annotation, l) // Do not allow two labels to be in the same
1057 // line if they overlap including padding, to
1058 // avoid situations like:
1065 && annotation.has_label() // Both labels must have some text, otherwise
1066 && next.has_label()) // they are not overlapping.
1067 // Do not add a new line if this annotation
1068 // or the next are vertical line placeholders.
1069 || (annotation.takes_space() // If either this or the next annotation is
1070 && next.has_label()) // multiline start/end, move it to a new line
1071 || (annotation.has_label() // so as not to overlap the horizontal lines.
1072 && next.takes_space())
1073 || (annotation.takes_space() && next.takes_space())
1074 || (overlaps(next, annotation, l)
1075 && next.end_col <= annotation.end_col
1080 // This annotation needs a new line in the output.
1086 line_len = max(line_len, p);
1093 // If there are no annotations or the only annotations on this line are
1094 // MultilineLine, then there's only code being shown, stop processing.
1095 if line.annotations.iter().all(|a| a.is_line()) {
1099 // Write the column separator.
1101 // After this we will have:
1110 for pos in 0..=line_len {
1111 draw_col_separator(buffer, line_offset + pos + 1, width_offset - 2);
1114 // Write the horizontal lines for multiline annotations
1115 // (only the first and last lines need this).
1117 // After this we will have:
1126 for &(pos, annotation) in &annotations_position {
1127 let style = if annotation.is_primary {
1128 Style::UnderlinePrimary
1130 Style::UnderlineSecondary
1133 match annotation.annotation_type {
1134 AnnotationType::MultilineStart(depth) | AnnotationType::MultilineEnd(depth) => {
1139 width_offset + depth,
1140 (code_offset + annotation.start_col).saturating_sub(left),
1144 _ if self.teach => {
1145 buffer.set_style_range(
1147 (code_offset + annotation.start_col).saturating_sub(left),
1148 (code_offset + annotation.end_col).saturating_sub(left),
1150 annotation.is_primary,
1157 // Write the vertical lines for labels that are on a different line as the underline.
1159 // After this we will have:
1168 for &(pos, annotation) in &annotations_position {
1169 let style = if annotation.is_primary {
1170 Style::UnderlinePrimary
1172 Style::UnderlineSecondary
1176 if pos > 1 && (annotation.has_label() || annotation.takes_space()) {
1177 for p in line_offset + 1..=line_offset + pos {
1180 (code_offset + annotation.start_col).saturating_sub(left),
1186 match annotation.annotation_type {
1187 AnnotationType::MultilineStart(depth) => {
1188 for p in line_offset + pos + 1..line_offset + line_len + 2 {
1189 buffer.putc(p, width_offset + depth - 1, '|', style);
1192 AnnotationType::MultilineEnd(depth) => {
1193 for p in line_offset..=line_offset + pos {
1194 buffer.putc(p, width_offset + depth - 1, '|', style);
1201 // Write the labels on the annotations that actually have a label.
1203 // After this we will have:
1208 // | something about `foo`
1212 for &(pos, annotation) in &annotations_position {
1214 if annotation.is_primary { Style::LabelPrimary } else { Style::LabelSecondary };
1215 let (pos, col) = if pos == 0 {
1216 (pos + 1, (annotation.end_col + 1).saturating_sub(left))
1218 (pos + 2, annotation.start_col.saturating_sub(left))
1220 if let Some(ref label) = annotation.label {
1221 buffer.puts(line_offset + pos, code_offset + col, &label, style);
1225 // Sort from biggest span to smallest span so that smaller spans are
1226 // represented in the output:
1231 // | | something about `foo`
1232 // | something about `fn foo()`
1233 annotations_position.sort_by_key(|(_, ann)| {
1234 // Decreasing order. When annotations share the same length, prefer `Primary`.
1235 (Reverse(ann.len()), ann.is_primary)
1238 // Write the underlines.
1240 // After this we will have:
1245 // | something about `foo`
1249 for &(_, annotation) in &annotations_position {
1250 let (underline, style) = if annotation.is_primary {
1251 ('^', Style::UnderlinePrimary)
1253 ('-', Style::UnderlineSecondary)
1255 for p in annotation.start_col..annotation.end_col {
1258 (code_offset + p).saturating_sub(left),
1264 annotations_position
1266 .filter_map(|&(_, annotation)| match annotation.annotation_type {
1267 AnnotationType::MultilineStart(p) | AnnotationType::MultilineEnd(p) => {
1268 let style = if annotation.is_primary {
1271 Style::LabelSecondary
1277 .collect::<Vec<_>>()
1280 fn get_multispan_max_line_num(&mut self, msp: &MultiSpan) -> usize {
1281 let Some(ref sm) = self.sm else {
1285 let will_be_emitted = |span: Span| {
1286 !span.is_dummy() && {
1287 let file = sm.lookup_source_file(span.hi());
1288 sm.ensure_source_file_source_present(file)
1293 for primary_span in msp.primary_spans() {
1294 if will_be_emitted(*primary_span) {
1295 let hi = sm.lookup_char_pos(primary_span.hi());
1296 max = (hi.line).max(max);
1299 if !self.short_message {
1300 for span_label in msp.span_labels() {
1301 if will_be_emitted(span_label.span) {
1302 let hi = sm.lookup_char_pos(span_label.span.hi());
1303 max = (hi.line).max(max);
1311 fn get_max_line_num(&mut self, span: &MultiSpan, children: &[SubDiagnostic]) -> usize {
1312 let primary = self.get_multispan_max_line_num(span);
1315 .map(|sub| self.get_multispan_max_line_num(&sub.span))
1321 /// Adds a left margin to every line but the first, given a padding length and the label being
1322 /// displayed, keeping the provided highlighting.
1325 buffer: &mut StyledBuffer,
1326 msg: &[(DiagnosticMessage, Style)],
1327 args: &FluentArgs<'_>,
1330 override_style: Option<Style>,
1332 // The extra 5 ` ` is padding that's always needed to align to the `note: `:
1335 // --> file.rs:13:20
1340 // = note: multiline
1345 // | | length of label
1347 // `max_line_num_len`
1348 let padding = " ".repeat(padding + label.len() + 5);
1350 /// Returns `override` if it is present and `style` is `NoStyle` or `style` otherwise
1351 fn style_or_override(style: Style, override_: Option<Style>) -> Style {
1352 match (style, override_) {
1353 (Style::NoStyle, Some(override_)) => override_,
1358 let mut line_number = 0;
1360 // Provided the following diagnostic message:
1364 // ("highlighted multiline\nstring to\nsee how it ", Style::NoStyle),
1365 // ("looks", Style::Highlight),
1366 // ("with\nvery ", Style::NoStyle),
1367 // ("weird", Style::Highlight),
1368 // (" formats\n", Style::NoStyle),
1369 // ("see?", Style::Highlight),
1372 // the expected output on a note is (* surround the highlighted text)
1374 // = note: highlighted multiline
1376 // see how it *looks* with
1377 // very *weird* formats
1379 for &(ref text, ref style) in msg.iter() {
1380 let text = self.translate_message(text, args);
1381 let lines = text.split('\n').collect::<Vec<_>>();
1382 if lines.len() > 1 {
1383 for (i, line) in lines.iter().enumerate() {
1386 buffer.append(line_number, &padding, Style::NoStyle);
1388 buffer.append(line_number, line, style_or_override(*style, override_style));
1391 buffer.append(line_number, &text, style_or_override(*style, override_style));
1396 fn emit_message_default(
1399 msg: &[(DiagnosticMessage, Style)],
1400 args: &FluentArgs<'_>,
1401 code: &Option<DiagnosticId>,
1403 max_line_num_len: usize,
1405 ) -> io::Result<()> {
1406 let mut buffer = StyledBuffer::new();
1408 if !msp.has_primary_spans() && !msp.has_span_labels() && is_secondary && !self.short_message
1410 // This is a secondary message with no span info
1411 for _ in 0..max_line_num_len {
1412 buffer.prepend(0, " ", Style::NoStyle);
1414 draw_note_separator(&mut buffer, 0, max_line_num_len + 1);
1415 if *level != Level::FailureNote {
1416 buffer.append(0, level.to_str(), Style::MainHeaderMsg);
1417 buffer.append(0, ": ", Style::NoStyle);
1419 self.msg_to_buffer(&mut buffer, msg, args, max_line_num_len, "note", None);
1421 let mut label_width = 0;
1422 // The failure note level itself does not provide any useful diagnostic information
1423 if *level != Level::FailureNote {
1424 buffer.append(0, level.to_str(), Style::Level(*level));
1425 label_width += level.to_str().len();
1427 // only render error codes, not lint codes
1428 if let Some(DiagnosticId::Error(ref code)) = *code {
1429 buffer.append(0, "[", Style::Level(*level));
1430 buffer.append(0, &code, Style::Level(*level));
1431 buffer.append(0, "]", Style::Level(*level));
1432 label_width += 2 + code.len();
1434 let header_style = if is_secondary { Style::HeaderMsg } else { Style::MainHeaderMsg };
1435 if *level != Level::FailureNote {
1436 buffer.append(0, ": ", header_style);
1439 for &(ref text, _) in msg.iter() {
1440 let text = self.translate_message(text, args);
1441 // Account for newlines to align output to its label.
1442 for (line, text) in normalize_whitespace(&text).lines().enumerate() {
1447 if line == 0 { String::new() } else { " ".repeat(label_width) },
1456 let mut annotated_files = FileWithAnnotatedLines::collect_annotations(self, args, msp);
1458 // Make sure our primary file comes first
1459 let (primary_lo, sm) = if let (Some(sm), Some(ref primary_span)) =
1460 (self.sm.as_ref(), msp.primary_span().as_ref())
1462 if !primary_span.is_dummy() {
1463 (sm.lookup_char_pos(primary_span.lo()), sm)
1465 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1469 // If we don't have span information, emit and exit
1470 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1474 annotated_files.binary_search_by(|x| x.file.name.cmp(&primary_lo.file.name))
1476 annotated_files.swap(0, pos);
1479 // Print out the annotate source lines that correspond with the error
1480 for annotated_file in annotated_files {
1481 // we can't annotate anything if the source is unavailable.
1482 if !sm.ensure_source_file_source_present(annotated_file.file.clone()) {
1486 // print out the span location and spacer before we print the annotated source
1487 // to do this, we need to know if this span will be primary
1488 let is_primary = primary_lo.file.name == annotated_file.file.name;
1490 let loc = primary_lo.clone();
1491 if !self.short_message {
1492 // remember where we are in the output buffer for easy reference
1493 let buffer_msg_line_offset = buffer.num_lines();
1495 buffer.prepend(buffer_msg_line_offset, "--> ", Style::LineNumber);
1497 buffer_msg_line_offset,
1500 sm.filename_for_diagnostics(&loc.file.name),
1501 sm.doctest_offset_line(&loc.file.name, loc.line),
1504 Style::LineAndColumn,
1506 for _ in 0..max_line_num_len {
1507 buffer.prepend(buffer_msg_line_offset, " ", Style::NoStyle);
1514 sm.filename_for_diagnostics(&loc.file.name),
1515 sm.doctest_offset_line(&loc.file.name, loc.line),
1518 Style::LineAndColumn,
1521 } else if !self.short_message {
1522 // remember where we are in the output buffer for easy reference
1523 let buffer_msg_line_offset = buffer.num_lines();
1526 draw_col_separator_no_space(
1528 buffer_msg_line_offset,
1529 max_line_num_len + 1,
1532 // Then, the secondary file indicator
1533 buffer.prepend(buffer_msg_line_offset + 1, "::: ", Style::LineNumber);
1534 let loc = if let Some(first_line) = annotated_file.lines.first() {
1535 let col = if let Some(first_annotation) = first_line.annotations.first() {
1536 format!(":{}", first_annotation.start_col + 1)
1542 sm.filename_for_diagnostics(&annotated_file.file.name),
1543 sm.doctest_offset_line(&annotated_file.file.name, first_line.line_index),
1547 format!("{}", sm.filename_for_diagnostics(&annotated_file.file.name))
1549 buffer.append(buffer_msg_line_offset + 1, &loc, Style::LineAndColumn);
1550 for _ in 0..max_line_num_len {
1551 buffer.prepend(buffer_msg_line_offset + 1, " ", Style::NoStyle);
1555 if !self.short_message {
1556 // Put in the spacer between the location and annotated source
1557 let buffer_msg_line_offset = buffer.num_lines();
1558 draw_col_separator_no_space(
1560 buffer_msg_line_offset,
1561 max_line_num_len + 1,
1564 // Contains the vertical lines' positions for active multiline annotations
1565 let mut multilines = FxHashMap::default();
1567 // Get the left-side margin to remove it
1568 let mut whitespace_margin = usize::MAX;
1569 for line_idx in 0..annotated_file.lines.len() {
1570 let file = annotated_file.file.clone();
1571 let line = &annotated_file.lines[line_idx];
1572 if let Some(source_string) = file.get_line(line.line_index - 1) {
1573 let leading_whitespace = source_string
1575 .take_while(|c| c.is_whitespace())
1578 // Tabs are displayed as 4 spaces
1584 if source_string.chars().any(|c| !c.is_whitespace()) {
1585 whitespace_margin = min(whitespace_margin, leading_whitespace);
1589 if whitespace_margin == usize::MAX {
1590 whitespace_margin = 0;
1593 // Left-most column any visible span points at.
1594 let mut span_left_margin = usize::MAX;
1595 for line in &annotated_file.lines {
1596 for ann in &line.annotations {
1597 span_left_margin = min(span_left_margin, ann.start_col);
1598 span_left_margin = min(span_left_margin, ann.end_col);
1601 if span_left_margin == usize::MAX {
1602 span_left_margin = 0;
1605 // Right-most column any visible span points at.
1606 let mut span_right_margin = 0;
1607 let mut label_right_margin = 0;
1608 let mut max_line_len = 0;
1609 for line in &annotated_file.lines {
1612 annotated_file.file.get_line(line.line_index - 1).map_or(0, |s| s.len()),
1614 for ann in &line.annotations {
1615 span_right_margin = max(span_right_margin, ann.start_col);
1616 span_right_margin = max(span_right_margin, ann.end_col);
1617 // FIXME: account for labels not in the same line
1618 let label_right = ann.label.as_ref().map_or(0, |l| l.len() + 1);
1619 label_right_margin = max(label_right_margin, ann.end_col + label_right);
1623 let width_offset = 3 + max_line_num_len;
1624 let code_offset = if annotated_file.multiline_depth == 0 {
1627 width_offset + annotated_file.multiline_depth + 1
1630 let column_width = if let Some(width) = self.diagnostic_width {
1631 width.saturating_sub(code_offset)
1632 } else if self.ui_testing {
1633 DEFAULT_COLUMN_WIDTH
1635 termize::dimensions()
1636 .map(|(w, _)| w.saturating_sub(code_offset))
1637 .unwrap_or(DEFAULT_COLUMN_WIDTH)
1640 let margin = Margin::new(
1649 // Next, output the annotate source for this file
1650 for line_idx in 0..annotated_file.lines.len() {
1651 let previous_buffer_line = buffer.num_lines();
1653 let depths = self.render_source_line(
1655 annotated_file.file.clone(),
1656 &annotated_file.lines[line_idx],
1662 let mut to_add = FxHashMap::default();
1664 for (depth, style) in depths {
1665 if multilines.remove(&depth).is_none() {
1666 to_add.insert(depth, style);
1670 // Set the multiline annotation vertical lines to the left of
1671 // the code in this line.
1672 for (depth, style) in &multilines {
1673 for line in previous_buffer_line..buffer.num_lines() {
1674 draw_multiline_line(&mut buffer, line, width_offset, *depth, *style);
1677 // check to see if we need to print out or elide lines that come between
1678 // this annotated line and the next one.
1679 if line_idx < (annotated_file.lines.len() - 1) {
1680 let line_idx_delta = annotated_file.lines[line_idx + 1].line_index
1681 - annotated_file.lines[line_idx].line_index;
1682 if line_idx_delta > 2 {
1683 let last_buffer_line_num = buffer.num_lines();
1684 buffer.puts(last_buffer_line_num, 0, "...", Style::LineNumber);
1686 // Set the multiline annotation vertical lines on `...` bridging line.
1687 for (depth, style) in &multilines {
1688 draw_multiline_line(
1690 last_buffer_line_num,
1696 } else if line_idx_delta == 2 {
1697 let unannotated_line = annotated_file
1699 .get_line(annotated_file.lines[line_idx].line_index)
1700 .unwrap_or_else(|| Cow::from(""));
1702 let last_buffer_line_num = buffer.num_lines();
1706 &normalize_whitespace(&unannotated_line),
1707 annotated_file.lines[line_idx + 1].line_index - 1,
1708 last_buffer_line_num,
1714 for (depth, style) in &multilines {
1715 draw_multiline_line(
1717 last_buffer_line_num,
1726 multilines.extend(&to_add);
1731 // final step: take our styled buffer, render it, then output it
1732 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1737 fn emit_suggestion_default(
1740 suggestion: &CodeSuggestion,
1741 args: &FluentArgs<'_>,
1743 max_line_num_len: usize,
1744 ) -> io::Result<()> {
1745 let Some(ref sm) = self.sm else {
1749 // Render the replacements for each suggestion
1750 let suggestions = suggestion.splice_lines(&**sm);
1751 debug!("emit_suggestion_default: suggestions={:?}", suggestions);
1753 if suggestions.is_empty() {
1754 // Suggestions coming from macros can have malformed spans. This is a heavy handed
1755 // approach to avoid ICEs by ignoring the suggestion outright.
1759 let mut buffer = StyledBuffer::new();
1761 // Render the suggestion message
1762 buffer.append(0, level.to_str(), Style::Level(*level));
1763 buffer.append(0, ": ", Style::HeaderMsg);
1767 &[(suggestion.msg.to_owned(), Style::NoStyle)],
1771 Some(Style::HeaderMsg),
1774 let mut row_num = 2;
1775 draw_col_separator_no_space(&mut buffer, 1, max_line_num_len + 1);
1776 let mut notice_capitalization = false;
1777 for (complete, parts, highlights, only_capitalization) in
1778 suggestions.iter().take(MAX_SUGGESTIONS)
1780 notice_capitalization |= only_capitalization;
1782 let has_deletion = parts.iter().any(|p| p.is_deletion());
1783 let is_multiline = complete.lines().count() > 1;
1785 if let Some(span) = span.primary_span() {
1786 // Compare the primary span of the diagnostic with the span of the suggestion
1787 // being emitted. If they belong to the same file, we don't *need* to show the
1788 // file name, saving in verbosity, but if it *isn't* we do need it, otherwise we're
1789 // telling users to make a change but not clarifying *where*.
1790 let loc = sm.lookup_char_pos(parts[0].span.lo());
1791 if loc.file.name != sm.span_to_filename(span) && loc.file.name.is_real() {
1792 buffer.puts(row_num - 1, 0, "--> ", Style::LineNumber);
1797 sm.filename_for_diagnostics(&loc.file.name),
1798 sm.doctest_offset_line(&loc.file.name, loc.line),
1801 Style::LineAndColumn,
1803 for _ in 0..max_line_num_len {
1804 buffer.prepend(row_num - 1, " ", Style::NoStyle);
1809 let show_code_change = if has_deletion && !is_multiline {
1810 DisplaySuggestion::Diff
1811 } else if (parts.len() != 1 || parts[0].snippet.trim() != complete.trim())
1814 DisplaySuggestion::Underline
1816 DisplaySuggestion::None
1819 if let DisplaySuggestion::Diff = show_code_change {
1824 .span_to_lines(parts[0].span)
1825 .expect("span_to_lines failed when emitting suggestion");
1827 assert!(!file_lines.lines.is_empty() || parts[0].span.is_dummy());
1829 let line_start = sm.lookup_char_pos(parts[0].span.lo()).line;
1830 draw_col_separator_no_space(&mut buffer, row_num - 1, max_line_num_len + 1);
1831 let mut lines = complete.lines();
1832 if lines.clone().next().is_none() {
1833 // Account for a suggestion to completely remove a line(s) with whitespace (#94192).
1834 let line_end = sm.lookup_char_pos(parts[0].span.hi()).line;
1835 for line in line_start..=line_end {
1837 row_num - 1 + line - line_start,
1839 &self.maybe_anonymized(line),
1843 row_num - 1 + line - line_start,
1844 max_line_num_len + 1,
1849 row_num - 1 + line - line_start,
1850 max_line_num_len + 3,
1851 &normalize_whitespace(&*file_lines.file.get_line(line - 1).unwrap()),
1855 row_num += line_end - line_start;
1857 let mut unhighlighted_lines = Vec::new();
1858 for (line_pos, (line, highlight_parts)) in lines.by_ref().zip(highlights).enumerate() {
1859 debug!(%line_pos, %line, ?highlight_parts);
1861 // Remember lines that are not highlighted to hide them if needed
1862 if highlight_parts.is_empty() {
1863 unhighlighted_lines.push((line_pos, line));
1867 match unhighlighted_lines.len() {
1869 // Since we show first line, "..." line and last line,
1870 // There is no reason to hide if there are 3 or less lines
1871 // (because then we just replace a line with ... which is
1873 n if n <= 3 => unhighlighted_lines.drain(..).for_each(|(p, l)| {
1874 self.draw_code_line(
1887 // Print first unhighlighted line, "..." and last unhighlighted line, like so:
1889 // LL | this line was highlighted
1890 // LL | this line is just for context
1892 // LL | this line is just for context
1893 // LL | this line was highlighted
1895 let last_line = unhighlighted_lines.pop();
1896 let first_line = unhighlighted_lines.drain(..).next();
1898 first_line.map(|(p, l)| {
1899 self.draw_code_line(
1913 buffer.puts(row_num, max_line_num_len - 1, "...", Style::LineNumber);
1916 last_line.map(|(p, l)| {
1917 self.draw_code_line(
1933 self.draw_code_line(
1947 // This offset and the ones below need to be signed to account for replacement code
1948 // that is shorter than the original code.
1949 let mut offsets: Vec<(usize, isize)> = Vec::new();
1950 // Only show an underline in the suggestions if the suggestion is not the
1951 // entirety of the code being shown and the displayed code is not multiline.
1952 if let DisplaySuggestion::Diff | DisplaySuggestion::Underline = show_code_change {
1953 draw_col_separator_no_space(&mut buffer, row_num, max_line_num_len + 1);
1955 let span_start_pos = sm.lookup_char_pos(part.span.lo()).col_display;
1956 let span_end_pos = sm.lookup_char_pos(part.span.hi()).col_display;
1958 // Do not underline the leading...
1959 let start = part.snippet.len().saturating_sub(part.snippet.trim_start().len());
1960 // ...or trailing spaces. Account for substitutions containing unicode
1962 let sub_len: usize = part
1966 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
1969 let offset: isize = offsets
1972 |(start, v)| if span_start_pos <= *start { None } else { Some(v) },
1975 let underline_start = (span_start_pos + start) as isize + offset;
1976 let underline_end = (span_start_pos + start + sub_len) as isize + offset;
1977 assert!(underline_start >= 0 && underline_end >= 0);
1978 let padding: usize = max_line_num_len + 3;
1979 for p in underline_start..underline_end {
1980 if let DisplaySuggestion::Underline = show_code_change {
1981 // If this is a replacement, underline with `^`, if this is an addition
1982 // underline with `+`.
1985 (padding as isize + p) as usize,
1986 if part.is_addition(&sm) { '+' } else { '~' },
1991 if let DisplaySuggestion::Diff = show_code_change {
1992 // Colorize removal with red in diff format.
1993 buffer.set_style_range(
1995 (padding as isize + span_start_pos as isize) as usize,
1996 (padding as isize + span_end_pos as isize) as usize,
2002 // length of the code after substitution
2003 let full_sub_len = part
2006 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
2007 .sum::<usize>() as isize;
2009 // length of the code to be substituted
2010 let snippet_len = span_end_pos as isize - span_start_pos as isize;
2011 // For multiple substitutions, use the position *after* the previous
2012 // substitutions have happened, only when further substitutions are
2013 // located strictly after.
2014 offsets.push((span_end_pos, full_sub_len - snippet_len));
2019 // if we elided some lines, add an ellipsis
2020 if lines.next().is_some() {
2021 buffer.puts(row_num, max_line_num_len - 1, "...", Style::LineNumber);
2022 } else if let DisplaySuggestion::None = show_code_change {
2023 draw_col_separator_no_space(&mut buffer, row_num, max_line_num_len + 1);
2027 if suggestions.len() > MAX_SUGGESTIONS {
2028 let others = suggestions.len() - MAX_SUGGESTIONS;
2029 let msg = format!("and {} other candidate{}", others, pluralize!(others));
2030 buffer.puts(row_num, max_line_num_len + 3, &msg, Style::NoStyle);
2031 } else if notice_capitalization {
2032 let msg = "notice the capitalization difference";
2033 buffer.puts(row_num, max_line_num_len + 3, &msg, Style::NoStyle);
2035 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
2039 fn emit_messages_default(
2042 message: &[(DiagnosticMessage, Style)],
2043 args: &FluentArgs<'_>,
2044 code: &Option<DiagnosticId>,
2046 children: &[SubDiagnostic],
2047 suggestions: &[CodeSuggestion],
2049 let max_line_num_len = if self.ui_testing {
2050 ANONYMIZED_LINE_NUM.len()
2052 let n = self.get_max_line_num(span, children);
2053 num_decimal_digits(n)
2056 match self.emit_message_default(span, message, args, code, level, max_line_num_len, false) {
2058 if !children.is_empty()
2059 || suggestions.iter().any(|s| s.style != SuggestionStyle::CompletelyHidden)
2061 let mut buffer = StyledBuffer::new();
2062 if !self.short_message {
2063 draw_col_separator_no_space(&mut buffer, 0, max_line_num_len + 1);
2065 if let Err(e) = emit_to_destination(
2071 panic!("failed to emit error: {}", e)
2074 if !self.short_message {
2075 for child in children {
2076 let span = child.render_span.as_ref().unwrap_or(&child.span);
2077 if let Err(err) = self.emit_message_default(
2086 panic!("failed to emit error: {}", err);
2089 for sugg in suggestions {
2090 if sugg.style == SuggestionStyle::CompletelyHidden {
2091 // do not display this suggestion, it is meant only for tools
2092 } else if sugg.style == SuggestionStyle::HideCodeAlways {
2093 if let Err(e) = self.emit_message_default(
2095 &[(sugg.msg.to_owned(), Style::HeaderMsg)],
2102 panic!("failed to emit error: {}", e);
2104 } else if let Err(e) = self.emit_suggestion_default(
2111 panic!("failed to emit error: {}", e);
2116 Err(e) => panic!("failed to emit error: {}", e),
2119 let mut dst = self.dst.writable();
2120 match writeln!(dst) {
2121 Err(e) => panic!("failed to emit error: {}", e),
2123 if let Err(e) = dst.flush() {
2124 panic!("failed to emit error: {}", e)
2132 buffer: &mut StyledBuffer,
2133 row_num: &mut usize,
2134 highlight_parts: &Vec<SubstitutionHighlight>,
2138 show_code_change: DisplaySuggestion,
2139 max_line_num_len: usize,
2140 file_lines: &FileLines,
2143 // Print the span column to avoid confusion
2144 buffer.puts(*row_num, 0, &self.maybe_anonymized(line_start + line_pos), Style::LineNumber);
2145 if let DisplaySuggestion::Diff = show_code_change {
2146 // Add the line number for both addition and removal to drive the point home.
2148 // N - fn foo<A: T>(bar: A) {
2149 // N + fn foo(bar: impl T) {
2153 &self.maybe_anonymized(line_start + line_pos),
2156 buffer.puts(*row_num - 1, max_line_num_len + 1, "- ", Style::Removal);
2159 max_line_num_len + 3,
2160 &normalize_whitespace(
2161 &*file_lines.file.get_line(file_lines.lines[line_pos].line_index).unwrap(),
2165 buffer.puts(*row_num, max_line_num_len + 1, "+ ", Style::Addition);
2166 } else if is_multiline {
2167 match &highlight_parts[..] {
2168 [SubstitutionHighlight { start: 0, end }] if *end == line.len() => {
2169 buffer.puts(*row_num, max_line_num_len + 1, "+ ", Style::Addition);
2172 draw_col_separator(buffer, *row_num, max_line_num_len + 1);
2175 buffer.puts(*row_num, max_line_num_len + 1, "~ ", Style::Addition);
2179 draw_col_separator(buffer, *row_num, max_line_num_len + 1);
2182 // print the suggestion
2183 buffer.append(*row_num, &normalize_whitespace(line), Style::NoStyle);
2185 // Colorize addition/replacements with green.
2186 for &SubstitutionHighlight { start, end } in highlight_parts {
2187 // Account for tabs when highlighting (#87972).
2188 let tabs: usize = line
2191 .map(|ch| match ch {
2196 buffer.set_style_range(
2198 max_line_num_len + 3 + start + tabs,
2199 max_line_num_len + 3 + end + tabs,
2208 #[derive(Clone, Copy)]
2209 enum DisplaySuggestion {
2215 impl FileWithAnnotatedLines {
2216 /// Preprocess all the annotations so that they are grouped by file and by line number
2217 /// This helps us quickly iterate over the whole message (including secondary file spans)
2218 pub fn collect_annotations(
2219 emitter: &dyn Emitter,
2220 args: &FluentArgs<'_>,
2222 ) -> Vec<FileWithAnnotatedLines> {
2223 fn add_annotation_to_file(
2224 file_vec: &mut Vec<FileWithAnnotatedLines>,
2225 file: Lrc<SourceFile>,
2229 for slot in file_vec.iter_mut() {
2230 // Look through each of our files for the one we're adding to
2231 if slot.file.name == file.name {
2232 // See if we already have a line for it
2233 for line_slot in &mut slot.lines {
2234 if line_slot.line_index == line_index {
2235 line_slot.annotations.push(ann);
2239 // We don't have a line yet, create one
2240 slot.lines.push(Line { line_index, annotations: vec![ann] });
2245 // This is the first time we're seeing the file
2246 file_vec.push(FileWithAnnotatedLines {
2248 lines: vec![Line { line_index, annotations: vec![ann] }],
2253 let mut output = vec![];
2254 let mut multiline_annotations = vec![];
2256 if let Some(ref sm) = emitter.source_map() {
2257 for span_label in msp.span_labels() {
2258 if span_label.span.is_dummy() {
2262 let lo = sm.lookup_char_pos(span_label.span.lo());
2263 let mut hi = sm.lookup_char_pos(span_label.span.hi());
2265 // Watch out for "empty spans". If we get a span like 6..6, we
2266 // want to just display a `^` at 6, so convert that to
2267 // 6..7. This is degenerate input, but it's best to degrade
2268 // gracefully -- and the parser likes to supply a span like
2269 // that for EOF, in particular.
2271 if lo.col_display == hi.col_display && lo.line == hi.line {
2272 hi.col_display += 1;
2275 if lo.line != hi.line {
2276 let ml = MultilineAnnotation {
2278 line_start: lo.line,
2280 start_col: lo.col_display,
2281 end_col: hi.col_display,
2282 is_primary: span_label.is_primary,
2286 .map(|m| emitter.translate_message(m, args).to_string()),
2287 overlaps_exactly: false,
2289 multiline_annotations.push((lo.file, ml));
2291 let ann = Annotation {
2292 start_col: lo.col_display,
2293 end_col: hi.col_display,
2294 is_primary: span_label.is_primary,
2298 .map(|m| emitter.translate_message(m, args).to_string()),
2299 annotation_type: AnnotationType::Singleline,
2301 add_annotation_to_file(&mut output, lo.file, lo.line, ann);
2306 // Find overlapping multiline annotations, put them at different depths
2307 multiline_annotations.sort_by_key(|&(_, ref ml)| (ml.line_start, ml.line_end));
2308 for (_, ann) in multiline_annotations.clone() {
2309 for (_, a) in multiline_annotations.iter_mut() {
2310 // Move all other multiline annotations overlapping with this one
2311 // one level to the right.
2312 if !(ann.same_span(a))
2313 && num_overlap(ann.line_start, ann.line_end, a.line_start, a.line_end, true)
2316 } else if ann.same_span(a) && &ann != a {
2317 a.overlaps_exactly = true;
2324 let mut max_depth = 0; // max overlapping multiline spans
2325 for (file, ann) in multiline_annotations {
2326 max_depth = max(max_depth, ann.depth);
2327 let mut end_ann = ann.as_end();
2328 if !ann.overlaps_exactly {
2329 // avoid output like
2351 add_annotation_to_file(&mut output, file.clone(), ann.line_start, ann.as_start());
2352 // 4 is the minimum vertical length of a multiline span when presented: two lines
2353 // of code and two lines of underline. This is not true for the special case where
2354 // the beginning doesn't have an underline, but the current logic seems to be
2355 // working correctly.
2356 let middle = min(ann.line_start + 4, ann.line_end);
2357 for line in ann.line_start + 1..middle {
2358 // Every `|` that joins the beginning of the span (`___^`) to the end (`|__^`).
2359 add_annotation_to_file(&mut output, file.clone(), line, ann.as_line());
2361 let line_end = ann.line_end - 1;
2362 if middle < line_end {
2363 add_annotation_to_file(&mut output, file.clone(), line_end, ann.as_line());
2366 end_ann.annotation_type = AnnotationType::Singleline;
2368 add_annotation_to_file(&mut output, file, ann.line_end, end_ann);
2370 for file_vec in output.iter_mut() {
2371 file_vec.multiline_depth = max_depth;
2377 // instead of taking the String length or dividing by 10 while > 0, we multiply a limit by 10 until
2378 // we're higher. If the loop isn't exited by the `return`, the last multiplication will wrap, which
2379 // is OK, because while we cannot fit a higher power of 10 in a usize, the loop will end anyway.
2380 // This is also why we need the max number of decimal digits within a `usize`.
2381 fn num_decimal_digits(num: usize) -> usize {
2382 #[cfg(target_pointer_width = "64")]
2383 const MAX_DIGITS: usize = 20;
2385 #[cfg(target_pointer_width = "32")]
2386 const MAX_DIGITS: usize = 10;
2388 #[cfg(target_pointer_width = "16")]
2389 const MAX_DIGITS: usize = 5;
2392 for num_digits in 1..MAX_DIGITS {
2396 lim = lim.wrapping_mul(10);
2401 // We replace some characters so the CLI output is always consistent and underlines aligned.
2402 const OUTPUT_REPLACEMENTS: &[(char, &str)] = &[
2403 ('\t', " "), // We do our own tab replacement
2404 ('\u{200D}', ""), // Replace ZWJ with nothing for consistent terminal output of grapheme clusters.
2405 ('\u{202A}', ""), // The following unicode text flow control characters are inconsistently
2406 ('\u{202B}', ""), // supported across CLIs and can cause confusion due to the bytes on disk
2407 ('\u{202D}', ""), // not corresponding to the visible source code, so we replace them always.
2416 fn normalize_whitespace(str: &str) -> String {
2417 let mut s = str.to_string();
2418 for (c, replacement) in OUTPUT_REPLACEMENTS {
2419 s = s.replace(*c, replacement);
2424 fn draw_col_separator(buffer: &mut StyledBuffer, line: usize, col: usize) {
2425 buffer.puts(line, col, "| ", Style::LineNumber);
2428 fn draw_col_separator_no_space(buffer: &mut StyledBuffer, line: usize, col: usize) {
2429 draw_col_separator_no_space_with_style(buffer, line, col, Style::LineNumber);
2432 fn draw_col_separator_no_space_with_style(
2433 buffer: &mut StyledBuffer,
2438 buffer.putc(line, col, '|', style);
2442 buffer: &mut StyledBuffer,
2449 for col in col_from..col_to {
2450 buffer.putc(line, col, symbol, style);
2454 fn draw_note_separator(buffer: &mut StyledBuffer, line: usize, col: usize) {
2455 buffer.puts(line, col, "= ", Style::LineNumber);
2458 fn draw_multiline_line(
2459 buffer: &mut StyledBuffer,
2465 buffer.putc(line, offset + depth - 1, '|', style);
2475 let extra = if inclusive { 1 } else { 0 };
2476 (b_start..b_end + extra).contains(&a_start) || (a_start..a_end + extra).contains(&b_start)
2478 fn overlaps(a1: &Annotation, a2: &Annotation, padding: usize) -> bool {
2479 num_overlap(a1.start_col, a1.end_col + padding, a2.start_col, a2.end_col, false)
2482 fn emit_to_destination(
2483 rendered_buffer: &[Vec<StyledString>],
2485 dst: &mut Destination,
2486 short_message: bool,
2487 ) -> io::Result<()> {
2490 let mut dst = dst.writable();
2492 // In order to prevent error message interleaving, where multiple error lines get intermixed
2493 // when multiple compiler processes error simultaneously, we emit errors with additional
2496 // On Unix systems, we write into a buffered terminal rather than directly to a terminal. When
2497 // the .flush() is called we take the buffer created from the buffered writes and write it at
2498 // one shot. Because the Unix systems use ANSI for the colors, which is a text-based styling
2499 // scheme, this buffered approach works and maintains the styling.
2501 // On Windows, styling happens through calls to a terminal API. This prevents us from using the
2502 // same buffering approach. Instead, we use a global Windows mutex, which we acquire long
2503 // enough to output the full error message, then we release.
2504 let _buffer_lock = lock::acquire_global_lock("rustc_errors");
2505 for (pos, line) in rendered_buffer.iter().enumerate() {
2507 dst.apply_style(*lvl, part.style)?;
2508 write!(dst, "{}", part.text)?;
2511 if !short_message && (!lvl.is_failure_note() || pos != rendered_buffer.len() - 1) {
2519 pub enum Destination {
2520 Terminal(StandardStream),
2521 Buffered(BufferWriter),
2522 // The bool denotes whether we should be emitting ansi color codes or not
2523 Raw(Box<(dyn Write + Send)>, bool),
2526 pub enum WritableDst<'a> {
2527 Terminal(&'a mut StandardStream),
2528 Buffered(&'a mut BufferWriter, Buffer),
2529 Raw(&'a mut (dyn Write + Send)),
2530 ColoredRaw(Ansi<&'a mut (dyn Write + Send)>),
2534 fn from_stderr(color: ColorConfig) -> Destination {
2535 let choice = color.to_color_choice();
2536 // On Windows we'll be performing global synchronization on the entire
2537 // system for emitting rustc errors, so there's no need to buffer
2540 // On non-Windows we rely on the atomicity of `write` to ensure errors
2541 // don't get all jumbled up.
2543 Terminal(StandardStream::stderr(choice))
2545 Buffered(BufferWriter::stderr(choice))
2549 fn writable(&mut self) -> WritableDst<'_> {
2551 Destination::Terminal(ref mut t) => WritableDst::Terminal(t),
2552 Destination::Buffered(ref mut t) => {
2553 let buf = t.buffer();
2554 WritableDst::Buffered(t, buf)
2556 Destination::Raw(ref mut t, false) => WritableDst::Raw(t),
2557 Destination::Raw(ref mut t, true) => WritableDst::ColoredRaw(Ansi::new(t)),
2561 fn supports_color(&self) -> bool {
2563 Self::Terminal(ref stream) => stream.supports_color(),
2564 Self::Buffered(ref buffer) => buffer.buffer().supports_color(),
2565 Self::Raw(_, supports_color) => supports_color,
2570 impl<'a> WritableDst<'a> {
2571 fn apply_style(&mut self, lvl: Level, style: Style) -> io::Result<()> {
2572 let mut spec = ColorSpec::new();
2574 Style::Addition => {
2575 spec.set_fg(Some(Color::Green)).set_intense(true);
2578 spec.set_fg(Some(Color::Red)).set_intense(true);
2580 Style::LineAndColumn => {}
2581 Style::LineNumber => {
2582 spec.set_bold(true);
2583 spec.set_intense(true);
2585 spec.set_fg(Some(Color::Cyan));
2587 spec.set_fg(Some(Color::Blue));
2590 Style::Quotation => {}
2591 Style::MainHeaderMsg => {
2592 spec.set_bold(true);
2594 spec.set_intense(true).set_fg(Some(Color::White));
2597 Style::UnderlinePrimary | Style::LabelPrimary => {
2599 spec.set_bold(true);
2601 Style::UnderlineSecondary | Style::LabelSecondary => {
2602 spec.set_bold(true).set_intense(true);
2604 spec.set_fg(Some(Color::Cyan));
2606 spec.set_fg(Some(Color::Blue));
2609 Style::HeaderMsg | Style::NoStyle => {}
2610 Style::Level(lvl) => {
2612 spec.set_bold(true);
2614 Style::Highlight => {
2615 spec.set_bold(true);
2618 self.set_color(&spec)
2621 fn set_color(&mut self, color: &ColorSpec) -> io::Result<()> {
2623 WritableDst::Terminal(ref mut t) => t.set_color(color),
2624 WritableDst::Buffered(_, ref mut t) => t.set_color(color),
2625 WritableDst::ColoredRaw(ref mut t) => t.set_color(color),
2626 WritableDst::Raw(_) => Ok(()),
2630 fn reset(&mut self) -> io::Result<()> {
2632 WritableDst::Terminal(ref mut t) => t.reset(),
2633 WritableDst::Buffered(_, ref mut t) => t.reset(),
2634 WritableDst::ColoredRaw(ref mut t) => t.reset(),
2635 WritableDst::Raw(_) => Ok(()),
2640 impl<'a> Write for WritableDst<'a> {
2641 fn write(&mut self, bytes: &[u8]) -> io::Result<usize> {
2643 WritableDst::Terminal(ref mut t) => t.write(bytes),
2644 WritableDst::Buffered(_, ref mut buf) => buf.write(bytes),
2645 WritableDst::Raw(ref mut w) => w.write(bytes),
2646 WritableDst::ColoredRaw(ref mut t) => t.write(bytes),
2650 fn flush(&mut self) -> io::Result<()> {
2652 WritableDst::Terminal(ref mut t) => t.flush(),
2653 WritableDst::Buffered(_, ref mut buf) => buf.flush(),
2654 WritableDst::Raw(ref mut w) => w.flush(),
2655 WritableDst::ColoredRaw(ref mut w) => w.flush(),
2660 impl<'a> Drop for WritableDst<'a> {
2661 fn drop(&mut self) {
2662 if let WritableDst::Buffered(ref mut dst, ref mut buf) = self {
2663 drop(dst.print(buf));
2668 /// Whether the original and suggested code are visually similar enough to warrant extra wording.
2669 pub fn is_case_difference(sm: &SourceMap, suggested: &str, sp: Span) -> bool {
2670 // FIXME: this should probably be extended to also account for `FO0` → `FOO` and unicode.
2671 let found = match sm.span_to_snippet(sp) {
2672 Ok(snippet) => snippet,
2674 warn!(error = ?e, "Invalid span {:?}", sp);
2678 let ascii_confusables = &['c', 'f', 'i', 'k', 'o', 's', 'u', 'v', 'w', 'x', 'y', 'z'];
2679 // All the chars that differ in capitalization are confusable (above):
2680 let confusable = iter::zip(found.chars(), suggested.chars())
2681 .filter(|(f, s)| f != s)
2682 .all(|(f, s)| (ascii_confusables.contains(&f) || ascii_confusables.contains(&s)));
2683 confusable && found.to_lowercase() == suggested.to_lowercase()
2684 // FIXME: We sometimes suggest the same thing we already have, which is a
2685 // bug, but be defensive against that here.
2686 && found != suggested