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;
17 use crate::translation::{to_fluent_args, Translate};
19 diagnostic::DiagnosticLocation, CodeSuggestion, Diagnostic, DiagnosticId, DiagnosticMessage,
20 FluentBundle, Handler, LazyFallbackBundle, Level, MultiSpan, SubDiagnostic,
21 SubstitutionHighlight, SuggestionStyle,
23 use rustc_lint_defs::pluralize;
25 use rustc_data_structures::fx::{FxHashMap, FxIndexMap};
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};
31 use std::io::prelude::*;
32 use std::io::{self, IsTerminal};
35 use termcolor::{Ansi, BufferWriter, ColorChoice, ColorSpec, StandardStream};
36 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: LazyFallbackBundle,
65 diagnostic_width: Option<usize>,
66 macro_backtrace: bool,
67 track_diagnostics: bool,
69 let (short, color_config) = self.unzip();
70 let color = color_config.suggests_using_colors();
86 #[derive(Clone, Copy, Debug)]
88 /// The available whitespace in the left that can be consumed when centering.
89 pub whitespace_left: usize,
90 /// The column of the beginning of left-most span.
92 /// The column of the end of right-most span.
93 pub span_right: usize,
94 /// The beginning of the line to be displayed.
95 pub computed_left: usize,
96 /// The end of the line to be displayed.
97 pub computed_right: usize,
98 /// The current width of the terminal. Uses value of `DEFAULT_COLUMN_WIDTH` constant by default
100 pub column_width: usize,
101 /// The end column of a span label, including the span. Doesn't account for labels not in the
102 /// same line as the span.
103 pub label_right: usize,
108 whitespace_left: usize,
115 // The 6 is padding to give a bit of room for `...` when displaying:
120 // 16 | ... fn foo(self) -> Self::Bar {
125 whitespace_left: whitespace_left.saturating_sub(6),
126 span_left: span_left.saturating_sub(6),
127 span_right: span_right + 6,
131 label_right: label_right + 6,
133 m.compute(max_line_len);
137 fn was_cut_left(&self) -> bool {
138 self.computed_left > 0
141 fn was_cut_right(&self, line_len: usize) -> bool {
143 if self.computed_right == self.span_right || self.computed_right == self.label_right {
144 // Account for the "..." padding given above. Otherwise we end up with code lines that
145 // do fit but end in "..." as if they were trimmed.
146 self.computed_right - 6
150 right < line_len && self.computed_left + self.column_width < line_len
153 fn compute(&mut self, max_line_len: usize) {
154 // When there's a lot of whitespace (>20), we want to trim it as it is useless.
155 self.computed_left = if self.whitespace_left > 20 {
156 self.whitespace_left - 16 // We want some padding.
160 // We want to show as much as possible, max_line_len is the right-most boundary for the
162 self.computed_right = max(max_line_len, self.computed_left);
164 if self.computed_right - self.computed_left > self.column_width {
165 // Trimming only whitespace isn't enough, let's get craftier.
166 if self.label_right - self.whitespace_left <= self.column_width {
167 // Attempt to fit the code window only trimming whitespace.
168 self.computed_left = self.whitespace_left;
169 self.computed_right = self.computed_left + self.column_width;
170 } else if self.label_right - self.span_left <= self.column_width {
171 // Attempt to fit the code window considering only the spans and labels.
172 let padding_left = (self.column_width - (self.label_right - self.span_left)) / 2;
173 self.computed_left = self.span_left.saturating_sub(padding_left);
174 self.computed_right = self.computed_left + self.column_width;
175 } else if self.span_right - self.span_left <= self.column_width {
176 // Attempt to fit the code window considering the spans and labels plus padding.
177 let padding_left = (self.column_width - (self.span_right - self.span_left)) / 5 * 2;
178 self.computed_left = self.span_left.saturating_sub(padding_left);
179 self.computed_right = self.computed_left + self.column_width;
181 // Mostly give up but still don't show the full line.
182 self.computed_left = self.span_left;
183 self.computed_right = self.span_right;
188 fn left(&self, line_len: usize) -> usize {
189 min(self.computed_left, line_len)
192 fn right(&self, line_len: usize) -> usize {
193 if line_len.saturating_sub(self.computed_left) <= self.column_width {
196 min(line_len, self.computed_right)
201 const ANONYMIZED_LINE_NUM: &str = "LL";
203 /// Emitter trait for emitting errors.
204 pub trait Emitter: Translate {
205 /// Emit a structured diagnostic.
206 fn emit_diagnostic(&mut self, diag: &Diagnostic);
208 /// Emit a notification that an artifact has been output.
209 /// This is currently only supported for the JSON format,
210 /// other formats can, and will, simply ignore it.
211 fn emit_artifact_notification(&mut self, _path: &Path, _artifact_type: &str) {}
213 fn emit_future_breakage_report(&mut self, _diags: Vec<Diagnostic>) {}
215 /// Emit list of unused externs
216 fn emit_unused_externs(
218 _lint_level: rustc_lint_defs::Level,
219 _unused_externs: &[&str],
223 /// Checks if should show explanations about "rustc --explain"
224 fn should_show_explain(&self) -> bool {
228 /// Checks if we can use colors in the current output stream.
229 fn supports_color(&self) -> bool {
233 fn source_map(&self) -> Option<&Lrc<SourceMap>>;
235 /// Formats the substitutions of the primary_span
237 /// There are a lot of conditions to this method, but in short:
239 /// * If the current `Diagnostic` has only one visible `CodeSuggestion`,
240 /// we format the `help` suggestion depending on the content of the
241 /// substitutions. In that case, we return the modified span only.
243 /// * If the current `Diagnostic` has multiple suggestions,
244 /// we return the original `primary_span` and the original suggestions.
245 fn primary_span_formatted<'a>(
247 diag: &'a Diagnostic,
248 fluent_args: &FluentArgs<'_>,
249 ) -> (MultiSpan, &'a [CodeSuggestion]) {
250 let mut primary_span = diag.span.clone();
251 let suggestions = diag.suggestions.as_deref().unwrap_or(&[]);
252 if let Some((sugg, rest)) = suggestions.split_first() {
253 let msg = self.translate_message(&sugg.msg, fluent_args);
254 if rest.is_empty() &&
255 // ^ if there is only one suggestion
256 // don't display multi-suggestions as labels
257 sugg.substitutions.len() == 1 &&
258 // don't display multipart suggestions as labels
259 sugg.substitutions[0].parts.len() == 1 &&
260 // don't display long messages as labels
261 msg.split_whitespace().count() < 10 &&
262 // don't display multiline suggestions as labels
263 !sugg.substitutions[0].parts[0].snippet.contains('\n') &&
265 // when this style is set we want the suggestion to be a message, not inline
266 SuggestionStyle::HideCodeAlways,
267 // trivial suggestion for tooling's sake, never shown
268 SuggestionStyle::CompletelyHidden,
269 // subtle suggestion, never shown inline
270 SuggestionStyle::ShowAlways,
271 ].contains(&sugg.style)
273 let substitution = &sugg.substitutions[0].parts[0].snippet.trim();
274 let msg = if substitution.is_empty() || sugg.style.hide_inline() {
275 // This substitution is only removal OR we explicitly don't want to show the
276 // code inline (`hide_inline`). Therefore, we don't show the substitution.
277 format!("help: {}", &msg)
279 // Show the default suggestion text with the substitution
285 .map(|sm| is_case_difference(
288 sugg.substitutions[0].parts[0].span,
292 " (notice the capitalization)"
299 primary_span.push_span_label(sugg.substitutions[0].parts[0].span, msg);
301 // We return only the modified primary_span
304 // if there are multiple suggestions, print them all in full
305 // to be consistent. We could try to figure out if we can
306 // make one (or the first one) inline, but that would give
307 // undue importance to a semi-random suggestion
308 (primary_span, suggestions)
311 (primary_span, suggestions)
315 fn fix_multispans_in_extern_macros_and_render_macro_backtrace(
317 span: &mut MultiSpan,
318 children: &mut Vec<SubDiagnostic>,
322 // Check for spans in macros, before `fix_multispans_in_extern_macros`
323 // has a chance to replace them.
324 let has_macro_spans: Vec<_> = iter::once(&*span)
325 .chain(children.iter().map(|child| &child.span))
326 .flat_map(|span| span.primary_spans())
327 .flat_map(|sp| sp.macro_backtrace())
328 .filter_map(|expn_data| {
329 match expn_data.kind {
330 ExpnKind::Root => None,
332 // Skip past non-macro entries, just in case there
333 // are some which do actually involve macros.
334 ExpnKind::Inlined | ExpnKind::Desugaring(..) | ExpnKind::AstPass(..) => None,
336 ExpnKind::Macro(macro_kind, name) => Some((macro_kind, name)),
342 self.fix_multispans_in_extern_macros(span, children);
345 self.render_multispans_macro_backtrace(span, children, backtrace);
348 if let Some((macro_kind, name)) = has_macro_spans.first() {
349 // Mark the actual macro this originates from
350 let and_then = if let Some((macro_kind, last_name)) = has_macro_spans.last()
353 let descr = macro_kind.descr();
355 " which comes from the expansion of the {descr} `{last_name}`",
361 let descr = macro_kind.descr();
363 "this {level} originates in the {descr} `{name}`{and_then} \
364 (in Nightly builds, run with -Z macro-backtrace for more info)",
367 children.push(SubDiagnostic {
369 message: vec![(DiagnosticMessage::Str(msg), Style::NoStyle)],
370 span: MultiSpan::new(),
377 fn render_multispans_macro_backtrace(
379 span: &mut MultiSpan,
380 children: &mut Vec<SubDiagnostic>,
383 for span in iter::once(span).chain(children.iter_mut().map(|child| &mut child.span)) {
384 self.render_multispan_macro_backtrace(span, backtrace);
388 fn render_multispan_macro_backtrace(&self, span: &mut MultiSpan, always_backtrace: bool) {
389 let mut new_labels: Vec<(Span, String)> = vec![];
391 for &sp in span.primary_spans() {
396 // FIXME(eddyb) use `retain` on `macro_backtrace` to remove all the
397 // entries we don't want to print, to make sure the indices being
398 // printed are contiguous (or omitted if there's only one entry).
399 let macro_backtrace: Vec<_> = sp.macro_backtrace().collect();
400 for (i, trace) in macro_backtrace.iter().rev().enumerate() {
401 if trace.def_site.is_dummy() {
405 if always_backtrace && !matches!(trace.kind, ExpnKind::Inlined) {
409 "in this expansion of `{}`{}",
411 if macro_backtrace.len() > 1 {
412 // if macro_backtrace.len() == 1 it'll be
413 // pointed at by "in this macro invocation"
414 format!(" (#{})", i + 1)
422 // Don't add a label on the call site if the diagnostic itself
423 // already points to (a part of) that call site, as the label
424 // is meant for showing the relevant invocation when the actual
425 // diagnostic is pointing to some part of macro definition.
427 // This also handles the case where an external span got replaced
428 // with the call site span by `fix_multispans_in_extern_macros`.
430 // NB: `-Zmacro-backtrace` overrides this, for uniformity, as the
431 // "in this expansion of" label above is always added in that mode,
432 // and it needs an "in this macro invocation" label to match that.
433 let redundant_span = trace.call_site.contains(sp);
435 if !redundant_span || always_backtrace {
436 let msg: Cow<'static, _> = match trace.kind {
437 ExpnKind::Macro(MacroKind::Attr, _) => {
438 "this procedural macro expansion".into()
440 ExpnKind::Macro(MacroKind::Derive, _) => {
441 "this derive macro expansion".into()
443 ExpnKind::Macro(MacroKind::Bang, _) => "this macro invocation".into(),
444 ExpnKind::Inlined => "this inlined function call".into(),
445 ExpnKind::Root => "the crate root".into(),
446 ExpnKind::AstPass(kind) => kind.descr().into(),
447 ExpnKind::Desugaring(kind) => {
448 format!("this {} desugaring", kind.descr()).into()
456 if macro_backtrace.len() > 1 && always_backtrace {
457 // only specify order when the macro
458 // backtrace is multiple levels deep
459 format!(" (#{})", i + 1)
466 if !always_backtrace {
472 for (label_span, label_text) in new_labels {
473 span.push_span_label(label_span, label_text);
477 // This does a small "fix" for multispans by looking to see if it can find any that
478 // point directly at external macros. Since these are often difficult to read,
479 // this will change the span to point at the use site.
480 fn fix_multispans_in_extern_macros(
482 span: &mut MultiSpan,
483 children: &mut Vec<SubDiagnostic>,
485 debug!("fix_multispans_in_extern_macros: before: span={:?} children={:?}", span, children);
486 self.fix_multispan_in_extern_macros(span);
487 for child in children.iter_mut() {
488 self.fix_multispan_in_extern_macros(&mut child.span);
490 debug!("fix_multispans_in_extern_macros: after: span={:?} children={:?}", span, children);
493 // This "fixes" MultiSpans that contain `Span`s pointing to locations inside of external macros.
494 // Since these locations are often difficult to read,
495 // we move these spans from the external macros to their corresponding use site.
496 fn fix_multispan_in_extern_macros(&self, span: &mut MultiSpan) {
497 let Some(source_map) = self.source_map() else { return };
498 // First, find all the spans in external macros and point instead at their use site.
499 let replacements: Vec<(Span, Span)> = span
503 .chain(span.span_labels().iter().map(|sp_label| sp_label.span))
505 if !sp.is_dummy() && source_map.is_imported(sp) {
506 let maybe_callsite = sp.source_callsite();
507 if sp != maybe_callsite {
508 return Some((sp, maybe_callsite));
515 // After we have them, make sure we replace these 'bad' def sites with their use sites.
516 for (from, to) in replacements {
517 span.replace(from, to);
522 impl Translate for EmitterWriter {
523 fn fluent_bundle(&self) -> Option<&Lrc<FluentBundle>> {
524 self.fluent_bundle.as_ref()
527 fn fallback_fluent_bundle(&self) -> &FluentBundle {
528 &self.fallback_bundle
532 impl Emitter for EmitterWriter {
533 fn source_map(&self) -> Option<&Lrc<SourceMap>> {
537 fn emit_diagnostic(&mut self, diag: &Diagnostic) {
538 let fluent_args = to_fluent_args(diag.args());
540 let mut children = diag.children.clone();
541 let (mut primary_span, suggestions) = self.primary_span_formatted(diag, &fluent_args);
542 debug!("emit_diagnostic: suggestions={:?}", suggestions);
544 self.fix_multispans_in_extern_macros_and_render_macro_backtrace(
548 self.macro_backtrace,
551 self.emit_messages_default(
559 self.track_diagnostics.then_some(&diag.emitted_at),
563 fn should_show_explain(&self) -> bool {
567 fn supports_color(&self) -> bool {
568 self.dst.supports_color()
572 /// An emitter that does nothing when emitting a non-fatal diagnostic.
573 /// Fatal diagnostics are forwarded to `fatal_handler` to avoid silent
574 /// failures of rustc, as witnessed e.g. in issue #89358.
575 pub struct SilentEmitter {
576 pub fatal_handler: Handler,
577 pub fatal_note: Option<String>,
580 impl Translate for SilentEmitter {
581 fn fluent_bundle(&self) -> Option<&Lrc<FluentBundle>> {
585 fn fallback_fluent_bundle(&self) -> &FluentBundle {
586 panic!("silent emitter attempted to translate message")
590 impl Emitter for SilentEmitter {
591 fn source_map(&self) -> Option<&Lrc<SourceMap>> {
595 fn emit_diagnostic(&mut self, d: &Diagnostic) {
596 if d.level == Level::Fatal {
597 let mut d = d.clone();
598 if let Some(ref note) = self.fatal_note {
601 self.fatal_handler.emit_diagnostic(&mut d);
606 /// Maximum number of suggestions to be shown
608 /// Arbitrary, but taken from trait import suggestion limit
609 pub const MAX_SUGGESTIONS: usize = 4;
611 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
612 pub enum ColorConfig {
619 fn to_color_choice(self) -> ColorChoice {
621 ColorConfig::Always => {
622 if io::stderr().is_terminal() {
625 ColorChoice::AlwaysAnsi
628 ColorConfig::Never => ColorChoice::Never,
629 ColorConfig::Auto if io::stderr().is_terminal() => ColorChoice::Auto,
630 ColorConfig::Auto => ColorChoice::Never,
633 fn suggests_using_colors(self) -> bool {
635 ColorConfig::Always | ColorConfig::Auto => true,
636 ColorConfig::Never => false,
641 /// Handles the writing of `HumanReadableErrorType::Default` and `HumanReadableErrorType::Short`
642 pub struct EmitterWriter {
644 sm: Option<Lrc<SourceMap>>,
645 fluent_bundle: Option<Lrc<FluentBundle>>,
646 fallback_bundle: LazyFallbackBundle,
650 diagnostic_width: Option<usize>,
652 macro_backtrace: bool,
653 track_diagnostics: bool,
657 pub struct FileWithAnnotatedLines {
658 pub file: Lrc<SourceFile>,
659 pub lines: Vec<Line>,
660 multiline_depth: usize,
665 color_config: ColorConfig,
666 source_map: Option<Lrc<SourceMap>>,
667 fluent_bundle: Option<Lrc<FluentBundle>>,
668 fallback_bundle: LazyFallbackBundle,
671 diagnostic_width: Option<usize>,
672 macro_backtrace: bool,
673 track_diagnostics: bool,
675 let dst = Destination::from_stderr(color_config);
691 dst: Box<dyn Write + Send>,
692 source_map: Option<Lrc<SourceMap>>,
693 fluent_bundle: Option<Lrc<FluentBundle>>,
694 fallback_bundle: LazyFallbackBundle,
698 diagnostic_width: Option<usize>,
699 macro_backtrace: bool,
700 track_diagnostics: bool,
703 dst: Raw(dst, colored),
716 pub fn ui_testing(mut self, ui_testing: bool) -> Self {
717 self.ui_testing = ui_testing;
721 fn maybe_anonymized(&self, line_num: usize) -> Cow<'static, str> {
723 Cow::Borrowed(ANONYMIZED_LINE_NUM)
725 Cow::Owned(line_num.to_string())
731 buffer: &mut StyledBuffer,
739 // Tabs are assumed to have been replaced by spaces in calling code.
740 debug_assert!(!source_string.contains('\t'));
741 let line_len = source_string.len();
742 // Create the source line we will highlight.
743 let left = margin.left(line_len);
744 let right = margin.right(line_len);
745 // On long lines, we strip the source line, accounting for unicode.
747 let code: String = source_string
751 // Make sure that the trimming on the right will fall within the terminal width.
752 // FIXME: `unicode_width` sometimes disagrees with terminals on how wide a `char` is.
753 // For now, just accept that sometimes the code line will be longer than desired.
754 let next = unicode_width::UnicodeWidthChar::width(*ch).unwrap_or(1);
755 if taken + next > right - left {
762 buffer.puts(line_offset, code_offset, &code, Style::Quotation);
763 if margin.was_cut_left() {
764 // We have stripped some code/whitespace from the beginning, make it clear.
765 buffer.puts(line_offset, code_offset, "...", Style::LineNumber);
767 if margin.was_cut_right(line_len) {
768 // We have stripped some code after the right-most span end, make it clear we did so.
769 buffer.puts(line_offset, code_offset + taken - 3, "...", Style::LineNumber);
771 buffer.puts(line_offset, 0, &self.maybe_anonymized(line_index), Style::LineNumber);
773 draw_col_separator_no_space(buffer, line_offset, width_offset - 2);
776 fn render_source_line(
778 buffer: &mut StyledBuffer,
779 file: Lrc<SourceFile>,
784 ) -> Vec<(usize, Style)> {
790 // | secondary span label
792 // ^^ ^ ^^^ ^^^^ ^^^ we don't care about code too far to the right of a span, we trim it
794 // | | | actual code found in your source code and the spans we use to mark it
795 // | | when there's too much wasted space to the left, trim it
796 // | vertical divider between the column number and the code
799 if line.line_index == 0 {
803 let source_string = match file.get_line(line.line_index - 1) {
804 Some(s) => normalize_whitespace(&s),
805 None => return Vec::new(),
808 let line_offset = buffer.num_lines();
811 let left = margin.left(source_string.len());
813 // Account for unicode characters of width !=0 that were removed.
814 let left = source_string
817 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
830 // Special case when there's only one annotation involved, it is the start of a multiline
831 // span and there's no text at the beginning of the code line. Instead of doing the whole
840 // we simplify the output to:
846 if let [ann] = &line.annotations[..] {
847 if let AnnotationType::MultilineStart(depth) = ann.annotation_type {
848 if source_string.chars().take(ann.start_col).all(|c| c.is_whitespace()) {
849 let style = if ann.is_primary {
850 Style::UnderlinePrimary
852 Style::UnderlineSecondary
854 buffer.putc(line_offset, width_offset + depth - 1, '/', style);
855 return vec![(depth, style)];
860 // We want to display like this:
862 // vec.push(vec.pop().unwrap());
863 // --- ^^^ - previous borrow ends here
865 // | error occurs here
866 // previous borrow of `vec` occurs here
868 // But there are some weird edge cases to be aware of:
870 // vec.push(vec.pop().unwrap());
871 // -------- - previous borrow ends here
873 // |this makes no sense
874 // previous borrow of `vec` occurs here
876 // For this reason, we group the lines into "highlight lines"
877 // and "annotations lines", where the highlight lines have the `^`.
879 // Sort the annotations by (start, end col)
880 // The labels are reversed, sort and then reversed again.
881 // Consider a list of annotations (A1, A2, C1, C2, B1, B2) where
882 // the letter signifies the span. Here we are only sorting by the
883 // span and hence, the order of the elements with the same span will
884 // not change. On reversing the ordering (|a, b| but b.cmp(a)), you get
885 // (C1, C2, B1, B2, A1, A2). All the elements with the same span are
886 // still ordered first to last, but all the elements with different
887 // spans are ordered by their spans in last to first order. Last to
888 // first order is important, because the jiggly lines and | are on
889 // the left, so the rightmost span needs to be rendered first,
890 // otherwise the lines would end up needing to go over a message.
892 let mut annotations = line.annotations.clone();
893 annotations.sort_by_key(|a| Reverse(a.start_col));
895 // First, figure out where each label will be positioned.
897 // In the case where you have the following annotations:
899 // vec.push(vec.pop().unwrap());
900 // -------- - previous borrow ends here [C]
902 // |this makes no sense [B]
903 // previous borrow of `vec` occurs here [A]
905 // `annotations_position` will hold [(2, A), (1, B), (0, C)].
907 // We try, when possible, to stick the rightmost annotation at the end
908 // of the highlight line:
910 // vec.push(vec.pop().unwrap());
911 // --- --- - previous borrow ends here
913 // But sometimes that's not possible because one of the other
914 // annotations overlaps it. For example, from the test
915 // `span_overlap_label`, we have the following annotations
916 // (written on distinct lines for clarity):
922 // In this case, we can't stick the rightmost-most label on
923 // the highlight line, or we would get:
930 // which is totally weird. Instead we want:
938 // which is...less weird, at least. In fact, in general, if
939 // the rightmost span overlaps with any other span, we should
940 // use the "hang below" version, so we can at least make it
941 // clear where the span *starts*. There's an exception for this
942 // logic, when the labels do not have a message:
957 let mut annotations_position = vec![];
958 let mut line_len = 0;
960 for (i, annotation) in annotations.iter().enumerate() {
961 for (j, next) in annotations.iter().enumerate() {
962 if overlaps(next, annotation, 0) // This label overlaps with another one and both
963 && annotation.has_label() // take space (they have text and are not
964 && j > i // multiline lines).
966 // We're currently on the first line, move the label one line down
968 // If we're overlapping with an un-labelled annotation with the same span
969 // we can just merge them in the output
970 if next.start_col == annotation.start_col
971 && next.end_col == annotation.end_col
977 // This annotation needs a new line in the output.
982 annotations_position.push((p, annotation));
983 for (j, next) in annotations.iter().enumerate() {
985 let l = next.label.as_ref().map_or(0, |label| label.len() + 2);
986 if (overlaps(next, annotation, l) // Do not allow two labels to be in the same
987 // line if they overlap including padding, to
988 // avoid situations like:
995 && annotation.has_label() // Both labels must have some text, otherwise
996 && next.has_label()) // they are not overlapping.
997 // Do not add a new line if this annotation
998 // or the next are vertical line placeholders.
999 || (annotation.takes_space() // If either this or the next annotation is
1000 && next.has_label()) // multiline start/end, move it to a new line
1001 || (annotation.has_label() // so as not to overlap the horizontal lines.
1002 && next.takes_space())
1003 || (annotation.takes_space() && next.takes_space())
1004 || (overlaps(next, annotation, l)
1005 && next.end_col <= annotation.end_col
1010 // This annotation needs a new line in the output.
1016 line_len = max(line_len, p);
1023 // If there are no annotations or the only annotations on this line are
1024 // MultilineLine, then there's only code being shown, stop processing.
1025 if line.annotations.iter().all(|a| a.is_line()) {
1029 // Write the column separator.
1031 // After this we will have:
1040 for pos in 0..=line_len {
1041 draw_col_separator(buffer, line_offset + pos + 1, width_offset - 2);
1044 // Write the horizontal lines for multiline annotations
1045 // (only the first and last lines need this).
1047 // After this we will have:
1056 for &(pos, annotation) in &annotations_position {
1057 let style = if annotation.is_primary {
1058 Style::UnderlinePrimary
1060 Style::UnderlineSecondary
1063 match annotation.annotation_type {
1064 AnnotationType::MultilineStart(depth) | AnnotationType::MultilineEnd(depth) => {
1069 width_offset + depth,
1070 (code_offset + annotation.start_col).saturating_sub(left),
1074 _ if self.teach => {
1075 buffer.set_style_range(
1077 (code_offset + annotation.start_col).saturating_sub(left),
1078 (code_offset + annotation.end_col).saturating_sub(left),
1080 annotation.is_primary,
1087 // Write the vertical lines for labels that are on a different line as the underline.
1089 // After this we will have:
1098 for &(pos, annotation) in &annotations_position {
1099 let style = if annotation.is_primary {
1100 Style::UnderlinePrimary
1102 Style::UnderlineSecondary
1106 if pos > 1 && (annotation.has_label() || annotation.takes_space()) {
1107 for p in line_offset + 1..=line_offset + pos {
1110 (code_offset + annotation.start_col).saturating_sub(left),
1116 match annotation.annotation_type {
1117 AnnotationType::MultilineStart(depth) => {
1118 for p in line_offset + pos + 1..line_offset + line_len + 2 {
1119 buffer.putc(p, width_offset + depth - 1, '|', style);
1122 AnnotationType::MultilineEnd(depth) => {
1123 for p in line_offset..=line_offset + pos {
1124 buffer.putc(p, width_offset + depth - 1, '|', style);
1131 // Write the labels on the annotations that actually have a label.
1133 // After this we will have:
1138 // | something about `foo`
1142 for &(pos, annotation) in &annotations_position {
1144 if annotation.is_primary { Style::LabelPrimary } else { Style::LabelSecondary };
1145 let (pos, col) = if pos == 0 {
1146 (pos + 1, (annotation.end_col + 1).saturating_sub(left))
1148 (pos + 2, annotation.start_col.saturating_sub(left))
1150 if let Some(ref label) = annotation.label {
1151 buffer.puts(line_offset + pos, code_offset + col, label, style);
1155 // Sort from biggest span to smallest span so that smaller spans are
1156 // represented in the output:
1161 // | | something about `foo`
1162 // | something about `fn foo()`
1163 annotations_position.sort_by_key(|(_, ann)| {
1164 // Decreasing order. When annotations share the same length, prefer `Primary`.
1165 (Reverse(ann.len()), ann.is_primary)
1168 // Write the underlines.
1170 // After this we will have:
1175 // | something about `foo`
1179 for &(_, annotation) in &annotations_position {
1180 let (underline, style) = if annotation.is_primary {
1181 ('^', Style::UnderlinePrimary)
1183 ('-', Style::UnderlineSecondary)
1185 for p in annotation.start_col..annotation.end_col {
1188 (code_offset + p).saturating_sub(left),
1194 annotations_position
1196 .filter_map(|&(_, annotation)| match annotation.annotation_type {
1197 AnnotationType::MultilineStart(p) | AnnotationType::MultilineEnd(p) => {
1198 let style = if annotation.is_primary {
1201 Style::LabelSecondary
1207 .collect::<Vec<_>>()
1210 fn get_multispan_max_line_num(&mut self, msp: &MultiSpan) -> usize {
1211 let Some(ref sm) = self.sm else {
1215 let will_be_emitted = |span: Span| {
1216 !span.is_dummy() && {
1217 let file = sm.lookup_source_file(span.hi());
1218 sm.ensure_source_file_source_present(file)
1223 for primary_span in msp.primary_spans() {
1224 if will_be_emitted(*primary_span) {
1225 let hi = sm.lookup_char_pos(primary_span.hi());
1226 max = (hi.line).max(max);
1229 if !self.short_message {
1230 for span_label in msp.span_labels() {
1231 if will_be_emitted(span_label.span) {
1232 let hi = sm.lookup_char_pos(span_label.span.hi());
1233 max = (hi.line).max(max);
1241 fn get_max_line_num(&mut self, span: &MultiSpan, children: &[SubDiagnostic]) -> usize {
1242 let primary = self.get_multispan_max_line_num(span);
1245 .map(|sub| self.get_multispan_max_line_num(&sub.span))
1251 /// Adds a left margin to every line but the first, given a padding length and the label being
1252 /// displayed, keeping the provided highlighting.
1255 buffer: &mut StyledBuffer,
1256 msg: &[(DiagnosticMessage, Style)],
1257 args: &FluentArgs<'_>,
1260 override_style: Option<Style>,
1262 // The extra 5 ` ` is padding that's always needed to align to the `note: `:
1265 // --> file.rs:13:20
1270 // = note: multiline
1275 // | | length of label
1277 // `max_line_num_len`
1278 let padding = " ".repeat(padding + label.len() + 5);
1280 /// Returns `override` if it is present and `style` is `NoStyle` or `style` otherwise
1281 fn style_or_override(style: Style, override_: Option<Style>) -> Style {
1282 match (style, override_) {
1283 (Style::NoStyle, Some(override_)) => override_,
1288 let mut line_number = 0;
1290 // Provided the following diagnostic message:
1294 // ("highlighted multiline\nstring to\nsee how it ", Style::NoStyle),
1295 // ("looks", Style::Highlight),
1296 // ("with\nvery ", Style::NoStyle),
1297 // ("weird", Style::Highlight),
1298 // (" formats\n", Style::NoStyle),
1299 // ("see?", Style::Highlight),
1302 // the expected output on a note is (* surround the highlighted text)
1304 // = note: highlighted multiline
1306 // see how it *looks* with
1307 // very *weird* formats
1309 for &(ref text, ref style) in msg.iter() {
1310 let text = self.translate_message(text, args);
1311 let lines = text.split('\n').collect::<Vec<_>>();
1312 if lines.len() > 1 {
1313 for (i, line) in lines.iter().enumerate() {
1316 buffer.append(line_number, &padding, Style::NoStyle);
1318 buffer.append(line_number, line, style_or_override(*style, override_style));
1321 buffer.append(line_number, &text, style_or_override(*style, override_style));
1326 fn emit_message_default(
1329 msg: &[(DiagnosticMessage, Style)],
1330 args: &FluentArgs<'_>,
1331 code: &Option<DiagnosticId>,
1333 max_line_num_len: usize,
1335 emitted_at: Option<&DiagnosticLocation>,
1336 ) -> io::Result<()> {
1337 let mut buffer = StyledBuffer::new();
1339 if !msp.has_primary_spans() && !msp.has_span_labels() && is_secondary && !self.short_message
1341 // This is a secondary message with no span info
1342 for _ in 0..max_line_num_len {
1343 buffer.prepend(0, " ", Style::NoStyle);
1345 draw_note_separator(&mut buffer, 0, max_line_num_len + 1);
1346 if *level != Level::FailureNote {
1347 buffer.append(0, level.to_str(), Style::MainHeaderMsg);
1348 buffer.append(0, ": ", Style::NoStyle);
1350 self.msg_to_buffer(&mut buffer, msg, args, max_line_num_len, "note", None);
1352 let mut label_width = 0;
1353 // The failure note level itself does not provide any useful diagnostic information
1354 if *level != Level::FailureNote {
1355 buffer.append(0, level.to_str(), Style::Level(*level));
1356 label_width += level.to_str().len();
1358 // only render error codes, not lint codes
1359 if let Some(DiagnosticId::Error(ref code)) = *code {
1360 buffer.append(0, "[", Style::Level(*level));
1361 buffer.append(0, code, Style::Level(*level));
1362 buffer.append(0, "]", Style::Level(*level));
1363 label_width += 2 + code.len();
1365 let header_style = if is_secondary { Style::HeaderMsg } else { Style::MainHeaderMsg };
1366 if *level != Level::FailureNote {
1367 buffer.append(0, ": ", header_style);
1370 for &(ref text, _) in msg.iter() {
1371 let text = self.translate_message(text, args);
1372 // Account for newlines to align output to its label.
1373 for (line, text) in normalize_whitespace(&text).lines().enumerate() {
1378 if line == 0 { String::new() } else { " ".repeat(label_width) },
1386 let mut annotated_files = FileWithAnnotatedLines::collect_annotations(self, args, msp);
1388 // Make sure our primary file comes first
1389 let (primary_lo, sm) = if let (Some(sm), Some(ref primary_span)) =
1390 (self.sm.as_ref(), msp.primary_span().as_ref())
1392 if !primary_span.is_dummy() {
1393 (sm.lookup_char_pos(primary_span.lo()), sm)
1395 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1399 // If we don't have span information, emit and exit
1400 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1404 annotated_files.binary_search_by(|x| x.file.name.cmp(&primary_lo.file.name))
1406 annotated_files.swap(0, pos);
1409 // Print out the annotate source lines that correspond with the error
1410 for annotated_file in annotated_files {
1411 // we can't annotate anything if the source is unavailable.
1412 if !sm.ensure_source_file_source_present(annotated_file.file.clone()) {
1416 // print out the span location and spacer before we print the annotated source
1417 // to do this, we need to know if this span will be primary
1418 let is_primary = primary_lo.file.name == annotated_file.file.name;
1420 let loc = primary_lo.clone();
1421 if !self.short_message {
1422 // remember where we are in the output buffer for easy reference
1423 let buffer_msg_line_offset = buffer.num_lines();
1425 buffer.prepend(buffer_msg_line_offset, "--> ", Style::LineNumber);
1427 buffer_msg_line_offset,
1430 sm.filename_for_diagnostics(&loc.file.name),
1431 sm.doctest_offset_line(&loc.file.name, loc.line),
1434 Style::LineAndColumn,
1436 for _ in 0..max_line_num_len {
1437 buffer.prepend(buffer_msg_line_offset, " ", Style::NoStyle);
1444 sm.filename_for_diagnostics(&loc.file.name),
1445 sm.doctest_offset_line(&loc.file.name, loc.line),
1448 Style::LineAndColumn,
1451 } else if !self.short_message {
1452 // remember where we are in the output buffer for easy reference
1453 let buffer_msg_line_offset = buffer.num_lines();
1456 draw_col_separator_no_space(
1458 buffer_msg_line_offset,
1459 max_line_num_len + 1,
1462 // Then, the secondary file indicator
1463 buffer.prepend(buffer_msg_line_offset + 1, "::: ", Style::LineNumber);
1464 let loc = if let Some(first_line) = annotated_file.lines.first() {
1465 let col = if let Some(first_annotation) = first_line.annotations.first() {
1466 format!(":{}", first_annotation.start_col + 1)
1472 sm.filename_for_diagnostics(&annotated_file.file.name),
1473 sm.doctest_offset_line(&annotated_file.file.name, first_line.line_index),
1477 format!("{}", sm.filename_for_diagnostics(&annotated_file.file.name))
1479 buffer.append(buffer_msg_line_offset + 1, &loc, Style::LineAndColumn);
1480 for _ in 0..max_line_num_len {
1481 buffer.prepend(buffer_msg_line_offset + 1, " ", Style::NoStyle);
1485 if !self.short_message {
1486 // Put in the spacer between the location and annotated source
1487 let buffer_msg_line_offset = buffer.num_lines();
1488 draw_col_separator_no_space(
1490 buffer_msg_line_offset,
1491 max_line_num_len + 1,
1494 // Contains the vertical lines' positions for active multiline annotations
1495 let mut multilines = FxIndexMap::default();
1497 // Get the left-side margin to remove it
1498 let mut whitespace_margin = usize::MAX;
1499 for line_idx in 0..annotated_file.lines.len() {
1500 let file = annotated_file.file.clone();
1501 let line = &annotated_file.lines[line_idx];
1502 if let Some(source_string) = file.get_line(line.line_index - 1) {
1503 let leading_whitespace = source_string
1505 .take_while(|c| c.is_whitespace())
1508 // Tabs are displayed as 4 spaces
1514 if source_string.chars().any(|c| !c.is_whitespace()) {
1515 whitespace_margin = min(whitespace_margin, leading_whitespace);
1519 if whitespace_margin == usize::MAX {
1520 whitespace_margin = 0;
1523 // Left-most column any visible span points at.
1524 let mut span_left_margin = usize::MAX;
1525 for line in &annotated_file.lines {
1526 for ann in &line.annotations {
1527 span_left_margin = min(span_left_margin, ann.start_col);
1528 span_left_margin = min(span_left_margin, ann.end_col);
1531 if span_left_margin == usize::MAX {
1532 span_left_margin = 0;
1535 // Right-most column any visible span points at.
1536 let mut span_right_margin = 0;
1537 let mut label_right_margin = 0;
1538 let mut max_line_len = 0;
1539 for line in &annotated_file.lines {
1542 annotated_file.file.get_line(line.line_index - 1).map_or(0, |s| s.len()),
1544 for ann in &line.annotations {
1545 span_right_margin = max(span_right_margin, ann.start_col);
1546 span_right_margin = max(span_right_margin, ann.end_col);
1547 // FIXME: account for labels not in the same line
1548 let label_right = ann.label.as_ref().map_or(0, |l| l.len() + 1);
1549 label_right_margin = max(label_right_margin, ann.end_col + label_right);
1553 let width_offset = 3 + max_line_num_len;
1554 let code_offset = if annotated_file.multiline_depth == 0 {
1557 width_offset + annotated_file.multiline_depth + 1
1560 let column_width = if let Some(width) = self.diagnostic_width {
1561 width.saturating_sub(code_offset)
1562 } else if self.ui_testing {
1563 DEFAULT_COLUMN_WIDTH
1565 termize::dimensions()
1566 .map(|(w, _)| w.saturating_sub(code_offset))
1567 .unwrap_or(DEFAULT_COLUMN_WIDTH)
1570 let margin = Margin::new(
1579 // Next, output the annotate source for this file
1580 for line_idx in 0..annotated_file.lines.len() {
1581 let previous_buffer_line = buffer.num_lines();
1583 let depths = self.render_source_line(
1585 annotated_file.file.clone(),
1586 &annotated_file.lines[line_idx],
1592 let mut to_add = FxHashMap::default();
1594 for (depth, style) in depths {
1595 if multilines.remove(&depth).is_none() {
1596 to_add.insert(depth, style);
1600 // Set the multiline annotation vertical lines to the left of
1601 // the code in this line.
1602 for (depth, style) in &multilines {
1603 for line in previous_buffer_line..buffer.num_lines() {
1604 draw_multiline_line(&mut buffer, line, width_offset, *depth, *style);
1607 // check to see if we need to print out or elide lines that come between
1608 // this annotated line and the next one.
1609 if line_idx < (annotated_file.lines.len() - 1) {
1610 let line_idx_delta = annotated_file.lines[line_idx + 1].line_index
1611 - annotated_file.lines[line_idx].line_index;
1612 if line_idx_delta > 2 {
1613 let last_buffer_line_num = buffer.num_lines();
1614 buffer.puts(last_buffer_line_num, 0, "...", Style::LineNumber);
1616 // Set the multiline annotation vertical lines on `...` bridging line.
1617 for (depth, style) in &multilines {
1618 draw_multiline_line(
1620 last_buffer_line_num,
1626 } else if line_idx_delta == 2 {
1627 let unannotated_line = annotated_file
1629 .get_line(annotated_file.lines[line_idx].line_index)
1630 .unwrap_or_else(|| Cow::from(""));
1632 let last_buffer_line_num = buffer.num_lines();
1636 &normalize_whitespace(&unannotated_line),
1637 annotated_file.lines[line_idx + 1].line_index - 1,
1638 last_buffer_line_num,
1644 for (depth, style) in &multilines {
1645 draw_multiline_line(
1647 last_buffer_line_num,
1656 multilines.extend(&to_add);
1661 if let Some(tracked) = emitted_at {
1662 let track = format!("-Ztrack-diagnostics: created at {tracked}");
1663 let len = buffer.num_lines();
1664 buffer.append(len, &track, Style::NoStyle);
1667 // final step: take our styled buffer, render it, then output it
1668 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1673 fn emit_suggestion_default(
1676 suggestion: &CodeSuggestion,
1677 args: &FluentArgs<'_>,
1679 max_line_num_len: usize,
1680 ) -> io::Result<()> {
1681 let Some(ref sm) = self.sm else {
1685 // Render the replacements for each suggestion
1686 let suggestions = suggestion.splice_lines(sm);
1687 debug!("emit_suggestion_default: suggestions={:?}", suggestions);
1689 if suggestions.is_empty() {
1690 // Suggestions coming from macros can have malformed spans. This is a heavy handed
1691 // approach to avoid ICEs by ignoring the suggestion outright.
1695 let mut buffer = StyledBuffer::new();
1697 // Render the suggestion message
1698 buffer.append(0, level.to_str(), Style::Level(*level));
1699 buffer.append(0, ": ", Style::HeaderMsg);
1703 &[(suggestion.msg.to_owned(), Style::NoStyle)],
1707 Some(Style::HeaderMsg),
1710 let mut row_num = 2;
1711 draw_col_separator_no_space(&mut buffer, 1, max_line_num_len + 1);
1712 let mut notice_capitalization = false;
1713 for (complete, parts, highlights, only_capitalization) in
1714 suggestions.iter().take(MAX_SUGGESTIONS)
1716 notice_capitalization |= only_capitalization;
1718 let has_deletion = parts.iter().any(|p| p.is_deletion(sm));
1719 let is_multiline = complete.lines().count() > 1;
1721 if let Some(span) = span.primary_span() {
1722 // Compare the primary span of the diagnostic with the span of the suggestion
1723 // being emitted. If they belong to the same file, we don't *need* to show the
1724 // file name, saving in verbosity, but if it *isn't* we do need it, otherwise we're
1725 // telling users to make a change but not clarifying *where*.
1726 let loc = sm.lookup_char_pos(parts[0].span.lo());
1727 if loc.file.name != sm.span_to_filename(span) && loc.file.name.is_real() {
1728 buffer.puts(row_num - 1, 0, "--> ", Style::LineNumber);
1733 sm.filename_for_diagnostics(&loc.file.name),
1734 sm.doctest_offset_line(&loc.file.name, loc.line),
1737 Style::LineAndColumn,
1739 for _ in 0..max_line_num_len {
1740 buffer.prepend(row_num - 1, " ", Style::NoStyle);
1745 let show_code_change = if has_deletion && !is_multiline {
1746 DisplaySuggestion::Diff
1747 } else if (parts.len() != 1 || parts[0].snippet.trim() != complete.trim())
1750 DisplaySuggestion::Underline
1752 DisplaySuggestion::None
1755 if let DisplaySuggestion::Diff = show_code_change {
1760 .span_to_lines(parts[0].span)
1761 .expect("span_to_lines failed when emitting suggestion");
1763 assert!(!file_lines.lines.is_empty() || parts[0].span.is_dummy());
1765 let line_start = sm.lookup_char_pos(parts[0].span.lo()).line;
1766 draw_col_separator_no_space(&mut buffer, row_num - 1, max_line_num_len + 1);
1767 let mut lines = complete.lines();
1768 if lines.clone().next().is_none() {
1769 // Account for a suggestion to completely remove a line(s) with whitespace (#94192).
1770 let line_end = sm.lookup_char_pos(parts[0].span.hi()).line;
1771 for line in line_start..=line_end {
1773 row_num - 1 + line - line_start,
1775 &self.maybe_anonymized(line),
1779 row_num - 1 + line - line_start,
1780 max_line_num_len + 1,
1785 row_num - 1 + line - line_start,
1786 max_line_num_len + 3,
1787 &normalize_whitespace(&file_lines.file.get_line(line - 1).unwrap()),
1791 row_num += line_end - line_start;
1793 let mut unhighlighted_lines = Vec::new();
1794 for (line_pos, (line, highlight_parts)) in lines.by_ref().zip(highlights).enumerate() {
1795 debug!(%line_pos, %line, ?highlight_parts);
1797 // Remember lines that are not highlighted to hide them if needed
1798 if highlight_parts.is_empty() {
1799 unhighlighted_lines.push((line_pos, line));
1803 match unhighlighted_lines.len() {
1805 // Since we show first line, "..." line and last line,
1806 // There is no reason to hide if there are 3 or less lines
1807 // (because then we just replace a line with ... which is
1809 n if n <= 3 => unhighlighted_lines.drain(..).for_each(|(p, l)| {
1810 self.draw_code_line(
1823 // Print first unhighlighted line, "..." and last unhighlighted line, like so:
1825 // LL | this line was highlighted
1826 // LL | this line is just for context
1828 // LL | this line is just for context
1829 // LL | this line was highlighted
1831 let last_line = unhighlighted_lines.pop();
1832 let first_line = unhighlighted_lines.drain(..).next();
1834 first_line.map(|(p, l)| {
1835 self.draw_code_line(
1849 buffer.puts(row_num, max_line_num_len - 1, "...", Style::LineNumber);
1852 last_line.map(|(p, l)| {
1853 self.draw_code_line(
1869 self.draw_code_line(
1883 // This offset and the ones below need to be signed to account for replacement code
1884 // that is shorter than the original code.
1885 let mut offsets: Vec<(usize, isize)> = Vec::new();
1886 // Only show an underline in the suggestions if the suggestion is not the
1887 // entirety of the code being shown and the displayed code is not multiline.
1888 if let DisplaySuggestion::Diff | DisplaySuggestion::Underline = show_code_change {
1889 draw_col_separator_no_space(&mut buffer, row_num, max_line_num_len + 1);
1891 let span_start_pos = sm.lookup_char_pos(part.span.lo()).col_display;
1892 let span_end_pos = sm.lookup_char_pos(part.span.hi()).col_display;
1894 // If this addition is _only_ whitespace, then don't trim it,
1895 // or else we're just not rendering anything.
1896 let is_whitespace_addition = part.snippet.trim().is_empty();
1898 // Do not underline the leading...
1899 let start = if is_whitespace_addition {
1902 part.snippet.len().saturating_sub(part.snippet.trim_start().len())
1904 // ...or trailing spaces. Account for substitutions containing unicode
1906 let sub_len: usize =
1907 if is_whitespace_addition { &part.snippet } else { part.snippet.trim() }
1909 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
1912 let offset: isize = offsets
1915 |(start, v)| if span_start_pos <= *start { None } else { Some(v) },
1918 let underline_start = (span_start_pos + start) as isize + offset;
1919 let underline_end = (span_start_pos + start + sub_len) as isize + offset;
1920 assert!(underline_start >= 0 && underline_end >= 0);
1921 let padding: usize = max_line_num_len + 3;
1922 for p in underline_start..underline_end {
1923 if let DisplaySuggestion::Underline = show_code_change {
1924 // If this is a replacement, underline with `^`, if this is an addition
1925 // underline with `+`.
1928 (padding as isize + p) as usize,
1929 if part.is_addition(sm) { '+' } else { '~' },
1934 if let DisplaySuggestion::Diff = show_code_change {
1935 // Colorize removal with red in diff format.
1936 buffer.set_style_range(
1938 (padding as isize + span_start_pos as isize) as usize,
1939 (padding as isize + span_end_pos as isize) as usize,
1945 // length of the code after substitution
1946 let full_sub_len = part
1949 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
1950 .sum::<usize>() as isize;
1952 // length of the code to be substituted
1953 let snippet_len = span_end_pos as isize - span_start_pos as isize;
1954 // For multiple substitutions, use the position *after* the previous
1955 // substitutions have happened, only when further substitutions are
1956 // located strictly after.
1957 offsets.push((span_end_pos, full_sub_len - snippet_len));
1962 // if we elided some lines, add an ellipsis
1963 if lines.next().is_some() {
1964 buffer.puts(row_num, max_line_num_len - 1, "...", Style::LineNumber);
1965 } else if let DisplaySuggestion::None = show_code_change {
1966 draw_col_separator_no_space(&mut buffer, row_num, max_line_num_len + 1);
1970 if suggestions.len() > MAX_SUGGESTIONS {
1971 let others = suggestions.len() - MAX_SUGGESTIONS;
1972 let msg = format!("and {} other candidate{}", others, pluralize!(others));
1973 buffer.puts(row_num, max_line_num_len + 3, &msg, Style::NoStyle);
1974 } else if notice_capitalization {
1975 let msg = "notice the capitalization difference";
1976 buffer.puts(row_num, max_line_num_len + 3, msg, Style::NoStyle);
1978 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1982 fn emit_messages_default(
1985 message: &[(DiagnosticMessage, Style)],
1986 args: &FluentArgs<'_>,
1987 code: &Option<DiagnosticId>,
1989 children: &[SubDiagnostic],
1990 suggestions: &[CodeSuggestion],
1991 emitted_at: Option<&DiagnosticLocation>,
1993 let max_line_num_len = if self.ui_testing {
1994 ANONYMIZED_LINE_NUM.len()
1996 let n = self.get_max_line_num(span, children);
1997 num_decimal_digits(n)
2000 match self.emit_message_default(
2011 if !children.is_empty()
2012 || suggestions.iter().any(|s| s.style != SuggestionStyle::CompletelyHidden)
2014 let mut buffer = StyledBuffer::new();
2015 if !self.short_message {
2016 draw_col_separator_no_space(&mut buffer, 0, max_line_num_len + 1);
2018 if let Err(e) = emit_to_destination(
2024 panic!("failed to emit error: {}", e)
2027 if !self.short_message {
2028 for child in children {
2029 let span = child.render_span.as_ref().unwrap_or(&child.span);
2030 if let Err(err) = self.emit_message_default(
2040 panic!("failed to emit error: {}", err);
2043 for sugg in suggestions {
2044 if sugg.style == SuggestionStyle::CompletelyHidden {
2045 // do not display this suggestion, it is meant only for tools
2046 } else if sugg.style == SuggestionStyle::HideCodeAlways {
2047 if let Err(e) = self.emit_message_default(
2049 &[(sugg.msg.to_owned(), Style::HeaderMsg)],
2057 panic!("failed to emit error: {}", e);
2059 } else if let Err(e) = self.emit_suggestion_default(
2066 panic!("failed to emit error: {}", e);
2071 Err(e) => panic!("failed to emit error: {}", e),
2074 let mut dst = self.dst.writable();
2075 match writeln!(dst) {
2076 Err(e) => panic!("failed to emit error: {}", e),
2078 if let Err(e) = dst.flush() {
2079 panic!("failed to emit error: {}", e)
2087 buffer: &mut StyledBuffer,
2088 row_num: &mut usize,
2089 highlight_parts: &Vec<SubstitutionHighlight>,
2093 show_code_change: DisplaySuggestion,
2094 max_line_num_len: usize,
2095 file_lines: &FileLines,
2098 // Print the span column to avoid confusion
2099 buffer.puts(*row_num, 0, &self.maybe_anonymized(line_start + line_pos), Style::LineNumber);
2100 if let DisplaySuggestion::Diff = show_code_change {
2101 // Add the line number for both addition and removal to drive the point home.
2103 // N - fn foo<A: T>(bar: A) {
2104 // N + fn foo(bar: impl T) {
2108 &self.maybe_anonymized(line_start + line_pos),
2111 buffer.puts(*row_num - 1, max_line_num_len + 1, "- ", Style::Removal);
2114 max_line_num_len + 3,
2115 &normalize_whitespace(
2116 &file_lines.file.get_line(file_lines.lines[line_pos].line_index).unwrap(),
2120 buffer.puts(*row_num, max_line_num_len + 1, "+ ", Style::Addition);
2121 } else if is_multiline {
2122 match &highlight_parts[..] {
2123 [SubstitutionHighlight { start: 0, end }] if *end == line.len() => {
2124 buffer.puts(*row_num, max_line_num_len + 1, "+ ", Style::Addition);
2127 draw_col_separator(buffer, *row_num, max_line_num_len + 1);
2130 buffer.puts(*row_num, max_line_num_len + 1, "~ ", Style::Addition);
2134 draw_col_separator(buffer, *row_num, max_line_num_len + 1);
2137 // print the suggestion
2138 buffer.append(*row_num, &normalize_whitespace(line), Style::NoStyle);
2140 // Colorize addition/replacements with green.
2141 for &SubstitutionHighlight { start, end } in highlight_parts {
2142 // Account for tabs when highlighting (#87972).
2143 let tabs: usize = line
2146 .map(|ch| match ch {
2151 buffer.set_style_range(
2153 max_line_num_len + 3 + start + tabs,
2154 max_line_num_len + 3 + end + tabs,
2163 #[derive(Clone, Copy, Debug)]
2164 enum DisplaySuggestion {
2170 impl FileWithAnnotatedLines {
2171 /// Preprocess all the annotations so that they are grouped by file and by line number
2172 /// This helps us quickly iterate over the whole message (including secondary file spans)
2173 pub fn collect_annotations(
2174 emitter: &dyn Emitter,
2175 args: &FluentArgs<'_>,
2177 ) -> Vec<FileWithAnnotatedLines> {
2178 fn add_annotation_to_file(
2179 file_vec: &mut Vec<FileWithAnnotatedLines>,
2180 file: Lrc<SourceFile>,
2184 for slot in file_vec.iter_mut() {
2185 // Look through each of our files for the one we're adding to
2186 if slot.file.name == file.name {
2187 // See if we already have a line for it
2188 for line_slot in &mut slot.lines {
2189 if line_slot.line_index == line_index {
2190 line_slot.annotations.push(ann);
2194 // We don't have a line yet, create one
2195 slot.lines.push(Line { line_index, annotations: vec![ann] });
2200 // This is the first time we're seeing the file
2201 file_vec.push(FileWithAnnotatedLines {
2203 lines: vec![Line { line_index, annotations: vec![ann] }],
2208 let mut output = vec![];
2209 let mut multiline_annotations = vec![];
2211 if let Some(ref sm) = emitter.source_map() {
2212 for span_label in msp.span_labels() {
2213 let fixup_lo_hi = |span: Span| {
2214 let lo = sm.lookup_char_pos(span.lo());
2215 let mut hi = sm.lookup_char_pos(span.hi());
2217 // Watch out for "empty spans". If we get a span like 6..6, we
2218 // want to just display a `^` at 6, so convert that to
2219 // 6..7. This is degenerate input, but it's best to degrade
2220 // gracefully -- and the parser likes to supply a span like
2221 // that for EOF, in particular.
2223 if lo.col_display == hi.col_display && lo.line == hi.line {
2224 hi.col_display += 1;
2229 if span_label.span.is_dummy() {
2230 if let Some(span) = msp.primary_span() {
2231 // if we don't know where to render the annotation, emit it as a note
2232 // on the primary span.
2234 let (lo, hi) = fixup_lo_hi(span);
2236 let ann = Annotation {
2237 start_col: lo.col_display,
2238 end_col: hi.col_display,
2239 is_primary: span_label.is_primary,
2243 .map(|m| emitter.translate_message(m, args).to_string()),
2244 annotation_type: AnnotationType::Singleline,
2246 add_annotation_to_file(&mut output, lo.file, lo.line, ann);
2251 let (lo, hi) = fixup_lo_hi(span_label.span);
2253 if lo.line != hi.line {
2254 let ml = MultilineAnnotation {
2256 line_start: lo.line,
2258 start_col: lo.col_display,
2259 end_col: hi.col_display,
2260 is_primary: span_label.is_primary,
2264 .map(|m| emitter.translate_message(m, args).to_string()),
2265 overlaps_exactly: false,
2267 multiline_annotations.push((lo.file, ml));
2269 let ann = Annotation {
2270 start_col: lo.col_display,
2271 end_col: hi.col_display,
2272 is_primary: span_label.is_primary,
2276 .map(|m| emitter.translate_message(m, args).to_string()),
2277 annotation_type: AnnotationType::Singleline,
2279 add_annotation_to_file(&mut output, lo.file, lo.line, ann);
2284 // Find overlapping multiline annotations, put them at different depths
2285 multiline_annotations.sort_by_key(|&(_, ref ml)| (ml.line_start, usize::MAX - ml.line_end));
2286 for (_, ann) in multiline_annotations.clone() {
2287 for (_, a) in multiline_annotations.iter_mut() {
2288 // Move all other multiline annotations overlapping with this one
2289 // one level to the right.
2290 if !(ann.same_span(a))
2291 && num_overlap(ann.line_start, ann.line_end, a.line_start, a.line_end, true)
2294 } else if ann.same_span(a) && &ann != a {
2295 a.overlaps_exactly = true;
2302 let mut max_depth = 0; // max overlapping multiline spans
2303 for (_, ann) in &multiline_annotations {
2304 max_depth = max(max_depth, ann.depth);
2306 // Change order of multispan depth to minimize the number of overlaps in the ASCII art.
2307 for (_, a) in multiline_annotations.iter_mut() {
2308 a.depth = max_depth - a.depth + 1;
2310 for (file, ann) in multiline_annotations {
2311 let mut end_ann = ann.as_end();
2312 if !ann.overlaps_exactly {
2313 // avoid output like
2335 add_annotation_to_file(&mut output, file.clone(), ann.line_start, ann.as_start());
2336 // 4 is the minimum vertical length of a multiline span when presented: two lines
2337 // of code and two lines of underline. This is not true for the special case where
2338 // the beginning doesn't have an underline, but the current logic seems to be
2339 // working correctly.
2340 let middle = min(ann.line_start + 4, ann.line_end);
2341 for line in ann.line_start + 1..middle {
2342 // Every `|` that joins the beginning of the span (`___^`) to the end (`|__^`).
2343 add_annotation_to_file(&mut output, file.clone(), line, ann.as_line());
2345 let line_end = ann.line_end - 1;
2346 if middle < line_end {
2347 add_annotation_to_file(&mut output, file.clone(), line_end, ann.as_line());
2350 end_ann.annotation_type = AnnotationType::Singleline;
2352 add_annotation_to_file(&mut output, file, ann.line_end, end_ann);
2354 for file_vec in output.iter_mut() {
2355 file_vec.multiline_depth = max_depth;
2361 // instead of taking the String length or dividing by 10 while > 0, we multiply a limit by 10 until
2362 // we're higher. If the loop isn't exited by the `return`, the last multiplication will wrap, which
2363 // is OK, because while we cannot fit a higher power of 10 in a usize, the loop will end anyway.
2364 // This is also why we need the max number of decimal digits within a `usize`.
2365 fn num_decimal_digits(num: usize) -> usize {
2366 #[cfg(target_pointer_width = "64")]
2367 const MAX_DIGITS: usize = 20;
2369 #[cfg(target_pointer_width = "32")]
2370 const MAX_DIGITS: usize = 10;
2372 #[cfg(target_pointer_width = "16")]
2373 const MAX_DIGITS: usize = 5;
2376 for num_digits in 1..MAX_DIGITS {
2380 lim = lim.wrapping_mul(10);
2385 // We replace some characters so the CLI output is always consistent and underlines aligned.
2386 const OUTPUT_REPLACEMENTS: &[(char, &str)] = &[
2387 ('\t', " "), // We do our own tab replacement
2388 ('\u{200D}', ""), // Replace ZWJ with nothing for consistent terminal output of grapheme clusters.
2389 ('\u{202A}', ""), // The following unicode text flow control characters are inconsistently
2390 ('\u{202B}', ""), // supported across CLIs and can cause confusion due to the bytes on disk
2391 ('\u{202D}', ""), // not corresponding to the visible source code, so we replace them always.
2400 fn normalize_whitespace(str: &str) -> String {
2401 let mut s = str.to_string();
2402 for (c, replacement) in OUTPUT_REPLACEMENTS {
2403 s = s.replace(*c, replacement);
2408 fn draw_col_separator(buffer: &mut StyledBuffer, line: usize, col: usize) {
2409 buffer.puts(line, col, "| ", Style::LineNumber);
2412 fn draw_col_separator_no_space(buffer: &mut StyledBuffer, line: usize, col: usize) {
2413 draw_col_separator_no_space_with_style(buffer, line, col, Style::LineNumber);
2416 fn draw_col_separator_no_space_with_style(
2417 buffer: &mut StyledBuffer,
2422 buffer.putc(line, col, '|', style);
2426 buffer: &mut StyledBuffer,
2433 for col in col_from..col_to {
2434 buffer.putc(line, col, symbol, style);
2438 fn draw_note_separator(buffer: &mut StyledBuffer, line: usize, col: usize) {
2439 buffer.puts(line, col, "= ", Style::LineNumber);
2442 fn draw_multiline_line(
2443 buffer: &mut StyledBuffer,
2449 buffer.putc(line, offset + depth - 1, '|', style);
2459 let extra = if inclusive { 1 } else { 0 };
2460 (b_start..b_end + extra).contains(&a_start) || (a_start..a_end + extra).contains(&b_start)
2462 fn overlaps(a1: &Annotation, a2: &Annotation, padding: usize) -> bool {
2463 num_overlap(a1.start_col, a1.end_col + padding, a2.start_col, a2.end_col, false)
2466 fn emit_to_destination(
2467 rendered_buffer: &[Vec<StyledString>],
2469 dst: &mut Destination,
2470 short_message: bool,
2471 ) -> io::Result<()> {
2474 let mut dst = dst.writable();
2476 // In order to prevent error message interleaving, where multiple error lines get intermixed
2477 // when multiple compiler processes error simultaneously, we emit errors with additional
2480 // On Unix systems, we write into a buffered terminal rather than directly to a terminal. When
2481 // the .flush() is called we take the buffer created from the buffered writes and write it at
2482 // one shot. Because the Unix systems use ANSI for the colors, which is a text-based styling
2483 // scheme, this buffered approach works and maintains the styling.
2485 // On Windows, styling happens through calls to a terminal API. This prevents us from using the
2486 // same buffering approach. Instead, we use a global Windows mutex, which we acquire long
2487 // enough to output the full error message, then we release.
2488 let _buffer_lock = lock::acquire_global_lock("rustc_errors");
2489 for (pos, line) in rendered_buffer.iter().enumerate() {
2491 dst.apply_style(*lvl, part.style)?;
2492 write!(dst, "{}", part.text)?;
2495 if !short_message && (!lvl.is_failure_note() || pos != rendered_buffer.len() - 1) {
2503 pub enum Destination {
2504 Terminal(StandardStream),
2505 Buffered(BufferWriter),
2506 // The bool denotes whether we should be emitting ansi color codes or not
2507 Raw(Box<(dyn Write + Send)>, bool),
2510 pub enum WritableDst<'a> {
2511 Terminal(&'a mut StandardStream),
2512 Buffered(&'a mut BufferWriter, Buffer),
2513 Raw(&'a mut (dyn Write + Send)),
2514 ColoredRaw(Ansi<&'a mut (dyn Write + Send)>),
2518 fn from_stderr(color: ColorConfig) -> Destination {
2519 let choice = color.to_color_choice();
2520 // On Windows we'll be performing global synchronization on the entire
2521 // system for emitting rustc errors, so there's no need to buffer
2524 // On non-Windows we rely on the atomicity of `write` to ensure errors
2525 // don't get all jumbled up.
2527 Terminal(StandardStream::stderr(choice))
2529 Buffered(BufferWriter::stderr(choice))
2533 fn writable(&mut self) -> WritableDst<'_> {
2535 Destination::Terminal(ref mut t) => WritableDst::Terminal(t),
2536 Destination::Buffered(ref mut t) => {
2537 let buf = t.buffer();
2538 WritableDst::Buffered(t, buf)
2540 Destination::Raw(ref mut t, false) => WritableDst::Raw(t),
2541 Destination::Raw(ref mut t, true) => WritableDst::ColoredRaw(Ansi::new(t)),
2545 fn supports_color(&self) -> bool {
2547 Self::Terminal(ref stream) => stream.supports_color(),
2548 Self::Buffered(ref buffer) => buffer.buffer().supports_color(),
2549 Self::Raw(_, supports_color) => supports_color,
2554 impl<'a> WritableDst<'a> {
2555 fn apply_style(&mut self, lvl: Level, style: Style) -> io::Result<()> {
2556 let mut spec = ColorSpec::new();
2558 Style::Addition => {
2559 spec.set_fg(Some(Color::Green)).set_intense(true);
2562 spec.set_fg(Some(Color::Red)).set_intense(true);
2564 Style::LineAndColumn => {}
2565 Style::LineNumber => {
2566 spec.set_bold(true);
2567 spec.set_intense(true);
2569 spec.set_fg(Some(Color::Cyan));
2571 spec.set_fg(Some(Color::Blue));
2574 Style::Quotation => {}
2575 Style::MainHeaderMsg => {
2576 spec.set_bold(true);
2578 spec.set_intense(true).set_fg(Some(Color::White));
2581 Style::UnderlinePrimary | Style::LabelPrimary => {
2583 spec.set_bold(true);
2585 Style::UnderlineSecondary | Style::LabelSecondary => {
2586 spec.set_bold(true).set_intense(true);
2588 spec.set_fg(Some(Color::Cyan));
2590 spec.set_fg(Some(Color::Blue));
2593 Style::HeaderMsg | Style::NoStyle => {}
2594 Style::Level(lvl) => {
2596 spec.set_bold(true);
2598 Style::Highlight => {
2599 spec.set_bold(true);
2602 self.set_color(&spec)
2605 fn set_color(&mut self, color: &ColorSpec) -> io::Result<()> {
2607 WritableDst::Terminal(ref mut t) => t.set_color(color),
2608 WritableDst::Buffered(_, ref mut t) => t.set_color(color),
2609 WritableDst::ColoredRaw(ref mut t) => t.set_color(color),
2610 WritableDst::Raw(_) => Ok(()),
2614 fn reset(&mut self) -> io::Result<()> {
2616 WritableDst::Terminal(ref mut t) => t.reset(),
2617 WritableDst::Buffered(_, ref mut t) => t.reset(),
2618 WritableDst::ColoredRaw(ref mut t) => t.reset(),
2619 WritableDst::Raw(_) => Ok(()),
2624 impl<'a> Write for WritableDst<'a> {
2625 fn write(&mut self, bytes: &[u8]) -> io::Result<usize> {
2627 WritableDst::Terminal(ref mut t) => t.write(bytes),
2628 WritableDst::Buffered(_, ref mut buf) => buf.write(bytes),
2629 WritableDst::Raw(ref mut w) => w.write(bytes),
2630 WritableDst::ColoredRaw(ref mut t) => t.write(bytes),
2634 fn flush(&mut self) -> io::Result<()> {
2636 WritableDst::Terminal(ref mut t) => t.flush(),
2637 WritableDst::Buffered(_, ref mut buf) => buf.flush(),
2638 WritableDst::Raw(ref mut w) => w.flush(),
2639 WritableDst::ColoredRaw(ref mut w) => w.flush(),
2644 impl<'a> Drop for WritableDst<'a> {
2645 fn drop(&mut self) {
2646 if let WritableDst::Buffered(ref mut dst, ref mut buf) = self {
2647 drop(dst.print(buf));
2652 /// Whether the original and suggested code are visually similar enough to warrant extra wording.
2653 pub fn is_case_difference(sm: &SourceMap, suggested: &str, sp: Span) -> bool {
2654 // FIXME: this should probably be extended to also account for `FO0` → `FOO` and unicode.
2655 let found = match sm.span_to_snippet(sp) {
2656 Ok(snippet) => snippet,
2658 warn!(error = ?e, "Invalid span {:?}", sp);
2662 let ascii_confusables = &['c', 'f', 'i', 'k', 'o', 's', 'u', 'v', 'w', 'x', 'y', 'z'];
2663 // All the chars that differ in capitalization are confusable (above):
2664 let confusable = iter::zip(found.chars(), suggested.chars())
2665 .filter(|(f, s)| f != s)
2666 .all(|(f, s)| (ascii_confusables.contains(&f) || ascii_confusables.contains(&s)));
2667 confusable && found.to_lowercase() == suggested.to_lowercase()
2668 // FIXME: We sometimes suggest the same thing we already have, which is a
2669 // bug, but be defensive against that here.
2670 && found != suggested