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 `librustc::session::config::ErrorOutputType`.
12 use syntax_pos::{SourceFile, Span, MultiSpan};
13 use syntax_pos::source_map::SourceMap;
16 Level, CodeSuggestion, Diagnostic, SubDiagnostic, pluralize,
17 SuggestionStyle, DiagnosticId,
19 use crate::Level::Error;
20 use crate::snippet::{Annotation, AnnotationType, Line, MultilineAnnotation, StyledString, Style};
21 use crate::styled_buffer::StyledBuffer;
23 use rustc_data_structures::fx::FxHashMap;
24 use rustc_data_structures::sync::Lrc;
26 use std::io::prelude::*;
28 use std::cmp::{min, max, Reverse};
30 use termcolor::{StandardStream, ColorChoice, ColorSpec, BufferWriter, Ansi};
31 use termcolor::{WriteColor, Color, Buffer};
33 /// Describes the way the content of the `rendered` field of the json output is generated
34 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
35 pub enum HumanReadableErrorType {
37 AnnotateSnippet(ColorConfig),
41 impl HumanReadableErrorType {
42 /// Returns a (`short`, `color`) tuple
43 pub fn unzip(self) -> (bool, ColorConfig) {
45 HumanReadableErrorType::Default(cc) => (false, cc),
46 HumanReadableErrorType::Short(cc) => (true, cc),
47 HumanReadableErrorType::AnnotateSnippet(cc) => (false, cc),
52 dst: Box<dyn Write + Send>,
53 source_map: Option<Lrc<SourceMap>>,
55 terminal_width: Option<usize>,
56 external_macro_backtrace: bool,
58 let (short, color_config) = self.unzip();
59 let color = color_config.suggests_using_colors();
60 EmitterWriter::new(dst, source_map, short, teach, color, terminal_width,
61 external_macro_backtrace)
65 #[derive(Clone, Copy, Debug)]
67 /// The available whitespace in the left that can be consumed when centering.
68 pub whitespace_left: usize,
69 /// The column of the beginning of left-most span.
71 /// The column of the end of right-most span.
72 pub span_right: usize,
73 /// The beginning of the line to be displayed.
74 pub computed_left: usize,
75 /// The end of the line to be displayed.
76 pub computed_right: usize,
77 /// The current width of the terminal. 140 by default and in tests.
78 pub column_width: usize,
79 /// The end column of a span label, including the span. Doesn't account for labels not in the
80 /// same line as the span.
81 pub label_right: usize,
86 whitespace_left: usize,
93 // The 6 is padding to give a bit of room for `...` when displaying:
98 // 16 | ... fn foo(self) -> Self::Bar {
103 whitespace_left: whitespace_left.saturating_sub(6),
104 span_left: span_left.saturating_sub(6),
105 span_right: span_right + 6,
109 label_right: label_right + 6,
111 m.compute(max_line_len);
115 fn was_cut_left(&self) -> bool {
116 self.computed_left > 0
119 fn was_cut_right(&self, line_len: usize) -> bool {
120 let right = if self.computed_right == self.span_right ||
121 self.computed_right == self.label_right
123 // Account for the "..." padding given above. Otherwise we end up with code lines that
124 // do fit but end in "..." as if they were trimmed.
125 self.computed_right - 6
129 right < line_len && self.computed_left + self.column_width < line_len
132 fn compute(&mut self, max_line_len: usize) {
133 // When there's a lot of whitespace (>20), we want to trim it as it is useless.
134 self.computed_left = if self.whitespace_left > 20 {
135 self.whitespace_left - 16 // We want some padding.
139 // We want to show as much as possible, max_line_len is the right-most boundary for the
141 self.computed_right = max(max_line_len, self.computed_left);
143 if self.computed_right - self.computed_left > self.column_width {
144 // Trimming only whitespace isn't enough, let's get craftier.
145 if self.label_right - self.whitespace_left <= self.column_width {
146 // Attempt to fit the code window only trimming whitespace.
147 self.computed_left = self.whitespace_left;
148 self.computed_right = self.computed_left + self.column_width;
149 } else if self.label_right - self.span_left <= self.column_width {
150 // Attempt to fit the code window considering only the spans and labels.
151 let padding_left = (self.column_width - (self.label_right - self.span_left)) / 2;
152 self.computed_left = self.span_left.saturating_sub(padding_left);
153 self.computed_right = self.computed_left + self.column_width;
154 } else if self.span_right - self.span_left <= self.column_width {
155 // Attempt to fit the code window considering the spans and labels plus padding.
156 let padding_left = (self.column_width - (self.span_right - self.span_left)) / 5 * 2;
157 self.computed_left = self.span_left.saturating_sub(padding_left);
158 self.computed_right = self.computed_left + self.column_width;
159 } else { // Mostly give up but still don't show the full line.
160 self.computed_left = self.span_left;
161 self.computed_right = self.span_right;
166 fn left(&self, line_len: usize) -> usize {
167 min(self.computed_left, line_len)
170 fn right(&self, line_len: usize) -> usize {
171 if line_len.saturating_sub(self.computed_left) <= self.column_width {
174 min(line_len, self.computed_right)
179 const ANONYMIZED_LINE_NUM: &str = "LL";
181 /// Emitter trait for emitting errors.
183 /// Emit a structured diagnostic.
184 fn emit_diagnostic(&mut self, diag: &Diagnostic);
186 /// Emit a notification that an artifact has been output.
187 /// This is currently only supported for the JSON format,
188 /// other formats can, and will, simply ignore it.
189 fn emit_artifact_notification(&mut self, _path: &Path, _artifact_type: &str) {}
191 /// Checks if should show explanations about "rustc --explain"
192 fn should_show_explain(&self) -> bool {
196 fn source_map(&self) -> Option<&Lrc<SourceMap>>;
198 /// Formats the substitutions of the primary_span
200 /// The are a lot of conditions to this method, but in short:
202 /// * If the current `Diagnostic` has only one visible `CodeSuggestion`,
203 /// we format the `help` suggestion depending on the content of the
204 /// substitutions. In that case, we return the modified span only.
206 /// * If the current `Diagnostic` has multiple suggestions,
207 /// we return the original `primary_span` and the original suggestions.
208 fn primary_span_formatted<'a>(
210 diag: &'a Diagnostic,
211 ) -> (MultiSpan, &'a [CodeSuggestion]) {
212 let mut primary_span = diag.span.clone();
213 if let Some((sugg, rest)) = diag.suggestions.split_first() {
214 if rest.is_empty() &&
215 // ^ if there is only one suggestion
216 // don't display multi-suggestions as labels
217 sugg.substitutions.len() == 1 &&
218 // don't display multipart suggestions as labels
219 sugg.substitutions[0].parts.len() == 1 &&
220 // don't display long messages as labels
221 sugg.msg.split_whitespace().count() < 10 &&
222 // don't display multiline suggestions as labels
223 !sugg.substitutions[0].parts[0].snippet.contains('\n') &&
225 // when this style is set we want the suggestion to be a message, not inline
226 SuggestionStyle::HideCodeAlways,
227 // trivial suggestion for tooling's sake, never shown
228 SuggestionStyle::CompletelyHidden,
229 // subtle suggestion, never shown inline
230 SuggestionStyle::ShowAlways,
231 ].contains(&sugg.style)
233 let substitution = &sugg.substitutions[0].parts[0].snippet.trim();
234 let msg = if substitution.len() == 0 || sugg.style.hide_inline() {
235 // This substitution is only removal OR we explicitly don't want to show the
236 // code inline (`hide_inline`). Therefore, we don't show the substitution.
237 format!("help: {}", sugg.msg)
239 // Show the default suggestion text with the substitution
243 if self.source_map().map(|sm| is_case_difference(
246 sugg.substitutions[0].parts[0].span,
247 )).unwrap_or(false) {
248 " (notice the capitalization)"
255 primary_span.push_span_label(sugg.substitutions[0].parts[0].span, msg);
257 // We return only the modified primary_span
260 // if there are multiple suggestions, print them all in full
261 // to be consistent. We could try to figure out if we can
262 // make one (or the first one) inline, but that would give
263 // undue importance to a semi-random suggestion
264 (primary_span, &diag.suggestions)
267 (primary_span, &diag.suggestions)
271 // This does a small "fix" for multispans by looking to see if it can find any that
272 // point directly at <*macros>. Since these are often difficult to read, this
273 // will change the span to point at the use site.
274 fn fix_multispans_in_std_macros(&self,
275 source_map: &Option<Lrc<SourceMap>>,
276 span: &mut MultiSpan,
277 children: &mut Vec<SubDiagnostic>,
280 let mut spans_updated = self.fix_multispan_in_std_macros(source_map, span, backtrace);
281 for child in children.iter_mut() {
282 spans_updated |= self.fix_multispan_in_std_macros(
288 let msg = if level == &Error {
289 "this error originates in a macro outside of the current crate \
290 (in Nightly builds, run with -Z external-macro-backtrace \
291 for more info)".to_string()
293 "this warning originates in a macro outside of the current crate \
294 (in Nightly builds, run with -Z external-macro-backtrace \
295 for more info)".to_string()
299 children.push(SubDiagnostic {
305 span: MultiSpan::new(),
311 // This "fixes" MultiSpans that contain Spans that are pointing to locations inside of
312 // <*macros>. Since these locations are often difficult to read, we move these Spans from
313 // <*macros> to their corresponding use site.
314 fn fix_multispan_in_std_macros(&self,
315 source_map: &Option<Lrc<SourceMap>>,
316 span: &mut MultiSpan,
317 always_backtrace: bool) -> bool {
318 let sm = match source_map {
320 None => return false,
323 let mut before_after: Vec<(Span, Span)> = vec![];
324 let mut new_labels: Vec<(Span, String)> = vec![];
326 // First, find all the spans in <*macros> and point instead at their use site
327 for sp in span.primary_spans() {
331 let call_sp = sm.call_span_if_macro(*sp);
332 if call_sp != *sp && !always_backtrace {
333 before_after.push((*sp, call_sp));
335 let backtrace_len = sp.macro_backtrace().len();
336 for (i, trace) in sp.macro_backtrace().iter().rev().enumerate() {
337 // Only show macro locations that are local
338 // and display them like a span_note
339 if trace.def_site_span.is_dummy() {
342 if always_backtrace {
343 new_labels.push((trace.def_site_span,
344 format!("in this expansion of `{}`{}",
345 trace.macro_decl_name,
346 if backtrace_len > 2 {
347 // if backtrace_len == 1 it'll be pointed
348 // at by "in this macro invocation"
349 format!(" (#{})", i + 1)
354 // Check to make sure we're not in any <*macros>
355 if !sm.span_to_filename(trace.def_site_span).is_macros() &&
356 !trace.macro_decl_name.starts_with("desugaring of ") &&
357 !trace.macro_decl_name.starts_with("#[") ||
359 new_labels.push((trace.call_site,
360 format!("in this macro invocation{}",
361 if backtrace_len > 2 && always_backtrace {
362 // only specify order when the macro
363 // backtrace is multiple levels deep
364 format!(" (#{})", i + 1)
368 if !always_backtrace {
374 for (label_span, label_text) in new_labels {
375 span.push_span_label(label_span, label_text);
377 for sp_label in span.span_labels() {
378 if sp_label.span.is_dummy() {
381 if sm.span_to_filename(sp_label.span.clone()).is_macros() &&
384 let v = sp_label.span.macro_backtrace();
385 if let Some(use_site) = v.last() {
386 before_after.push((sp_label.span.clone(), use_site.call_site.clone()));
390 // After we have them, make sure we replace these 'bad' def sites with their use sites
391 let spans_updated = !before_after.is_empty();
392 for (before, after) in before_after {
393 span.replace(before, after);
400 impl Emitter for EmitterWriter {
401 fn source_map(&self) -> Option<&Lrc<SourceMap>> {
405 fn emit_diagnostic(&mut self, diag: &Diagnostic) {
406 let mut children = diag.children.clone();
407 let (mut primary_span, suggestions) = self.primary_span_formatted(&diag);
409 self.fix_multispans_in_std_macros(&self.sm,
413 self.external_macro_backtrace);
415 self.emit_messages_default(&diag.level,
416 &diag.styled_message(),
423 fn should_show_explain(&self) -> bool {
428 /// An emitter that does nothing when emitting a diagnostic.
429 pub struct SilentEmitter;
431 impl Emitter for SilentEmitter {
432 fn source_map(&self) -> Option<&Lrc<SourceMap>> { None }
433 fn emit_diagnostic(&mut self, _: &Diagnostic) {}
436 /// maximum number of lines we will print for each error; arbitrary.
437 pub const MAX_HIGHLIGHT_LINES: usize = 6;
438 /// maximum number of suggestions to be shown
440 /// Arbitrary, but taken from trait import suggestion limit
441 pub const MAX_SUGGESTIONS: usize = 4;
443 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
444 pub enum ColorConfig {
451 fn to_color_choice(self) -> ColorChoice {
453 ColorConfig::Always => {
454 if atty::is(atty::Stream::Stderr) {
457 ColorChoice::AlwaysAnsi
460 ColorConfig::Never => ColorChoice::Never,
461 ColorConfig::Auto if atty::is(atty::Stream::Stderr) => {
464 ColorConfig::Auto => ColorChoice::Never,
467 fn suggests_using_colors(self) -> bool {
469 | ColorConfig::Always
472 ColorConfig::Never => false,
477 /// Handles the writing of `HumanReadableErrorType::Default` and `HumanReadableErrorType::Short`
478 pub struct EmitterWriter {
480 sm: Option<Lrc<SourceMap>>,
484 terminal_width: Option<usize>,
486 external_macro_backtrace: bool,
490 pub struct FileWithAnnotatedLines {
491 pub file: Lrc<SourceFile>,
492 pub lines: Vec<Line>,
493 multiline_depth: usize,
498 color_config: ColorConfig,
499 source_map: Option<Lrc<SourceMap>>,
502 terminal_width: Option<usize>,
503 external_macro_backtrace: bool,
505 let dst = Destination::from_stderr(color_config);
513 external_macro_backtrace,
518 dst: Box<dyn Write + Send>,
519 source_map: Option<Lrc<SourceMap>>,
523 terminal_width: Option<usize>,
524 external_macro_backtrace: bool,
527 dst: Raw(dst, colored),
533 external_macro_backtrace,
537 pub fn ui_testing(mut self, ui_testing: bool) -> Self {
538 self.ui_testing = ui_testing;
542 fn maybe_anonymized(&self, line_num: usize) -> String {
544 ANONYMIZED_LINE_NUM.to_string()
552 buffer: &mut StyledBuffer,
560 let line_len = source_string.len();
561 // Create the source line we will highlight.
562 let left = margin.left(line_len);
563 let right = margin.right(line_len);
564 // On long lines, we strip the source line, accounting for unicode.
566 let code: String = source_string.chars().skip(left).take_while(|ch| {
567 // Make sure that the trimming on the right will fall within the terminal width.
568 // FIXME: `unicode_width` sometimes disagrees with terminals on how wide a `char` is.
569 // For now, just accept that sometimes the code line will be longer than desired.
570 let next = unicode_width::UnicodeWidthChar::width(*ch).unwrap_or(1);
571 if taken + next > right - left {
577 buffer.puts(line_offset, code_offset, &code, Style::Quotation);
578 if margin.was_cut_left() {
579 // We have stripped some code/whitespace from the beginning, make it clear.
580 buffer.puts(line_offset, code_offset, "...", Style::LineNumber);
582 if margin.was_cut_right(line_len) {
583 // We have stripped some code after the right-most span end, make it clear we did so.
584 buffer.puts(line_offset, code_offset + taken - 3, "...", Style::LineNumber);
586 buffer.puts(line_offset, 0, &self.maybe_anonymized(line_index), Style::LineNumber);
588 draw_col_separator(buffer, line_offset, width_offset - 2);
591 fn render_source_line(
593 buffer: &mut StyledBuffer,
594 file: Lrc<SourceFile>,
599 ) -> Vec<(usize, Style)> {
605 // | secondary span label
607 // ^^ ^ ^^^ ^^^^ ^^^ we don't care about code too far to the right of a span, we trim it
609 // | | | actual code found in your source code and the spans we use to mark it
610 // | | when there's too much wasted space to the left, trim it
611 // | vertical divider between the column number and the code
614 if line.line_index == 0 {
618 let source_string = match file.get_line(line.line_index - 1) {
620 None => return Vec::new(),
623 let line_offset = buffer.num_lines();
625 let left = margin.left(source_string.len()); // Left trim
626 // Account for unicode characters of width !=0 that were removed.
627 let left = source_string.chars().take(left)
628 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
641 // Special case when there's only one annotation involved, it is the start of a multiline
642 // span and there's no text at the beginning of the code line. Instead of doing the whole
651 // we simplify the output to:
657 if let [ann] = &line.annotations[..] {
658 if let AnnotationType::MultilineStart(depth) = ann.annotation_type {
659 if source_string.chars().take(ann.start_col).all(|c| c.is_whitespace()) {
660 let style = if ann.is_primary {
661 Style::UnderlinePrimary
663 Style::UnderlineSecondary
665 buffer.putc(line_offset, width_offset + depth - 1, '/', style);
666 return vec![(depth, style)];
671 // We want to display like this:
673 // vec.push(vec.pop().unwrap());
674 // --- ^^^ - previous borrow ends here
676 // | error occurs here
677 // previous borrow of `vec` occurs here
679 // But there are some weird edge cases to be aware of:
681 // vec.push(vec.pop().unwrap());
682 // -------- - previous borrow ends here
684 // |this makes no sense
685 // previous borrow of `vec` occurs here
687 // For this reason, we group the lines into "highlight lines"
688 // and "annotations lines", where the highlight lines have the `^`.
690 // Sort the annotations by (start, end col)
691 // The labels are reversed, sort and then reversed again.
692 // Consider a list of annotations (A1, A2, C1, C2, B1, B2) where
693 // the letter signifies the span. Here we are only sorting by the
694 // span and hence, the order of the elements with the same span will
695 // not change. On reversing the ordering (|a, b| but b.cmp(a)), you get
696 // (C1, C2, B1, B2, A1, A2). All the elements with the same span are
697 // still ordered first to last, but all the elements with different
698 // spans are ordered by their spans in last to first order. Last to
699 // first order is important, because the jiggly lines and | are on
700 // the left, so the rightmost span needs to be rendered first,
701 // otherwise the lines would end up needing to go over a message.
703 let mut annotations = line.annotations.clone();
704 annotations.sort_by_key(|a| Reverse(a.start_col));
706 // First, figure out where each label will be positioned.
708 // In the case where you have the following annotations:
710 // vec.push(vec.pop().unwrap());
711 // -------- - previous borrow ends here [C]
713 // |this makes no sense [B]
714 // previous borrow of `vec` occurs here [A]
716 // `annotations_position` will hold [(2, A), (1, B), (0, C)].
718 // We try, when possible, to stick the rightmost annotation at the end
719 // of the highlight line:
721 // vec.push(vec.pop().unwrap());
722 // --- --- - previous borrow ends here
724 // But sometimes that's not possible because one of the other
725 // annotations overlaps it. For example, from the test
726 // `span_overlap_label`, we have the following annotations
727 // (written on distinct lines for clarity):
733 // In this case, we can't stick the rightmost-most label on
734 // the highlight line, or we would get:
741 // which is totally weird. Instead we want:
749 // which is...less weird, at least. In fact, in general, if
750 // the rightmost span overlaps with any other span, we should
751 // use the "hang below" version, so we can at least make it
752 // clear where the span *starts*. There's an exception for this
753 // logic, when the labels do not have a message:
768 let mut annotations_position = vec![];
769 let mut line_len = 0;
771 for (i, annotation) in annotations.iter().enumerate() {
772 for (j, next) in annotations.iter().enumerate() {
773 if overlaps(next, annotation, 0) // This label overlaps with another one and both
774 && annotation.has_label() // take space (they have text and are not
775 && j > i // multiline lines).
776 && p == 0 // We're currently on the first line, move the label one line down
778 // If we're overlapping with an un-labelled annotation with the same span
779 // we can just merge them in the output
780 if next.start_col == annotation.start_col
781 && next.end_col == annotation.end_col
787 // This annotation needs a new line in the output.
792 annotations_position.push((p, annotation));
793 for (j, next) in annotations.iter().enumerate() {
795 let l = next.label.as_ref().map_or(0, |label| label.len() + 2);
796 if (overlaps(next, annotation, l) // Do not allow two labels to be in the same
797 // line if they overlap including padding, to
798 // avoid situations like:
805 && annotation.has_label() // Both labels must have some text, otherwise
806 && next.has_label()) // they are not overlapping.
807 // Do not add a new line if this annotation
808 // or the next are vertical line placeholders.
809 || (annotation.takes_space() // If either this or the next annotation is
810 && next.has_label()) // multiline start/end, move it to a new line
811 || (annotation.has_label() // so as not to overlap the orizontal lines.
812 && next.takes_space())
813 || (annotation.takes_space() && next.takes_space())
814 || (overlaps(next, annotation, l)
815 && next.end_col <= annotation.end_col
817 && p == 0) // Avoid #42595.
819 // This annotation needs a new line in the output.
825 line_len = max(line_len, p);
832 // If there are no annotations or the only annotations on this line are
833 // MultilineLine, then there's only code being shown, stop processing.
834 if line.annotations.iter().all(|a| a.is_line()) {
838 // Write the colunmn separator.
840 // After this we will have:
849 for pos in 0..=line_len {
850 draw_col_separator(buffer, line_offset + pos + 1, width_offset - 2);
851 buffer.putc(line_offset + pos + 1,
857 // Write the horizontal lines for multiline annotations
858 // (only the first and last lines need this).
860 // After this we will have:
869 for &(pos, annotation) in &annotations_position {
870 let style = if annotation.is_primary {
871 Style::UnderlinePrimary
873 Style::UnderlineSecondary
876 match annotation.annotation_type {
877 AnnotationType::MultilineStart(depth) |
878 AnnotationType::MultilineEnd(depth) => {
883 width_offset + depth,
884 code_offset + annotation.start_col - left,
889 buffer.set_style_range(
891 code_offset + annotation.start_col - left,
892 code_offset + annotation.end_col - left,
894 annotation.is_primary,
901 // Write the vertical lines for labels that are on a different line as the underline.
903 // After this we will have:
912 for &(pos, annotation) in &annotations_position {
913 let style = if annotation.is_primary {
914 Style::UnderlinePrimary
916 Style::UnderlineSecondary
920 if pos > 1 && (annotation.has_label() || annotation.takes_space()) {
921 for p in line_offset + 1..=line_offset + pos {
923 code_offset + annotation.start_col - margin.computed_left,
928 match annotation.annotation_type {
929 AnnotationType::MultilineStart(depth) => {
930 for p in line_offset + pos + 1..line_offset + line_len + 2 {
932 width_offset + depth - 1,
937 AnnotationType::MultilineEnd(depth) => {
938 for p in line_offset..=line_offset + pos {
940 width_offset + depth - 1,
949 // Write the labels on the annotations that actually have a label.
951 // After this we will have:
956 // | something about `foo`
960 for &(pos, annotation) in &annotations_position {
961 let style = if annotation.is_primary {
964 Style::LabelSecondary
966 let (pos, col) = if pos == 0 {
967 (pos + 1, (annotation.end_col + 1).saturating_sub(left))
969 (pos + 2, annotation.start_col.saturating_sub(left))
971 if let Some(ref label) = annotation.label {
972 buffer.puts(line_offset + pos, code_offset + col, &label, style);
976 // Sort from biggest span to smallest span so that smaller spans are
977 // represented in the output:
982 // | | something about `foo`
983 // | something about `fn foo()`
984 annotations_position.sort_by_key(|(_, ann)| {
985 // Decreasing order. When annotations share the same length, prefer `Primary`.
986 (Reverse(ann.len()), ann.is_primary)
989 // Write the underlines.
991 // After this we will have:
996 // | something about `foo`
1000 for &(_, annotation) in &annotations_position {
1001 let (underline, style) = if annotation.is_primary {
1002 ('^', Style::UnderlinePrimary)
1004 ('-', Style::UnderlineSecondary)
1006 for p in annotation.start_col..annotation.end_col {
1009 (code_offset + p).saturating_sub(left),
1015 annotations_position.iter().filter_map(|&(_, annotation)| {
1016 match annotation.annotation_type {
1017 AnnotationType::MultilineStart(p) | AnnotationType::MultilineEnd(p) => {
1018 let style = if annotation.is_primary {
1021 Style::LabelSecondary
1028 }).collect::<Vec<_>>()
1031 fn get_multispan_max_line_num(&mut self, msp: &MultiSpan) -> usize {
1032 let sm = match self.sm {
1038 for primary_span in msp.primary_spans() {
1039 if !primary_span.is_dummy() {
1040 let hi = sm.lookup_char_pos(primary_span.hi());
1041 max = (hi.line).max(max);
1044 if !self.short_message {
1045 for span_label in msp.span_labels() {
1046 if !span_label.span.is_dummy() {
1047 let hi = sm.lookup_char_pos(span_label.span.hi());
1048 max = (hi.line).max(max);
1056 fn get_max_line_num(&mut self, span: &MultiSpan, children: &[SubDiagnostic]) -> usize {
1057 let primary = self.get_multispan_max_line_num(span);
1059 .map(|sub| self.get_multispan_max_line_num(&sub.span))
1065 /// Adds a left margin to every line but the first, given a padding length and the label being
1066 /// displayed, keeping the provided highlighting.
1067 fn msg_to_buffer(&self,
1068 buffer: &mut StyledBuffer,
1069 msg: &[(String, Style)],
1072 override_style: Option<Style>) {
1074 // The extra 5 ` ` is padding that's always needed to align to the `note: `:
1077 // --> file.rs:13:20
1082 // = note: multiline
1087 // | | length of label
1089 // `max_line_num_len`
1090 let padding = " ".repeat(padding + label.len() + 5);
1092 /// Returns `override` if it is present and `style` is `NoStyle` or `style` otherwise
1093 fn style_or_override(style: Style, override_: Option<Style>) -> Style {
1094 match (style, override_) {
1095 (Style::NoStyle, Some(override_)) => override_,
1100 let mut line_number = 0;
1102 // Provided the following diagnostic message:
1106 // ("highlighted multiline\nstring to\nsee how it ", Style::NoStyle),
1107 // ("looks", Style::Highlight),
1108 // ("with\nvery ", Style::NoStyle),
1109 // ("weird", Style::Highlight),
1110 // (" formats\n", Style::NoStyle),
1111 // ("see?", Style::Highlight),
1114 // the expected output on a note is (* surround the highlighted text)
1116 // = note: highlighted multiline
1118 // see how it *looks* with
1119 // very *weird* formats
1121 for &(ref text, ref style) in msg.iter() {
1122 let lines = text.split('\n').collect::<Vec<_>>();
1123 if lines.len() > 1 {
1124 for (i, line) in lines.iter().enumerate() {
1127 buffer.append(line_number, &padding, Style::NoStyle);
1129 buffer.append(line_number, line, style_or_override(*style, override_style));
1132 buffer.append(line_number, text, style_or_override(*style, override_style));
1137 fn emit_message_default(
1140 msg: &[(String, Style)],
1141 code: &Option<DiagnosticId>,
1143 max_line_num_len: usize,
1145 ) -> io::Result<()> {
1146 let mut buffer = StyledBuffer::new();
1147 let header_style = if is_secondary {
1150 Style::MainHeaderMsg
1153 if !msp.has_primary_spans() && !msp.has_span_labels() && is_secondary
1154 && !self.short_message {
1155 // This is a secondary message with no span info
1156 for _ in 0..max_line_num_len {
1157 buffer.prepend(0, " ", Style::NoStyle);
1159 draw_note_separator(&mut buffer, 0, max_line_num_len + 1);
1160 if *level != Level::FailureNote {
1161 let level_str = level.to_string();
1162 if !level_str.is_empty() {
1163 buffer.append(0, &level_str, Style::MainHeaderMsg);
1164 buffer.append(0, ": ", Style::NoStyle);
1167 self.msg_to_buffer(&mut buffer, msg, max_line_num_len, "note", None);
1169 let level_str = level.to_string();
1170 // The failure note level itself does not provide any useful diagnostic information
1171 if *level != Level::FailureNote && !level_str.is_empty() {
1172 buffer.append(0, &level_str, Style::Level(level.clone()));
1174 // only render error codes, not lint codes
1175 if let Some(DiagnosticId::Error(ref code)) = *code {
1176 buffer.append(0, "[", Style::Level(level.clone()));
1177 buffer.append(0, &code, Style::Level(level.clone()));
1178 buffer.append(0, "]", Style::Level(level.clone()));
1180 if *level != Level::FailureNote && !level_str.is_empty() {
1181 buffer.append(0, ": ", header_style);
1183 for &(ref text, _) in msg.iter() {
1184 buffer.append(0, text, header_style);
1188 let mut annotated_files = FileWithAnnotatedLines::collect_annotations(msp, &self.sm);
1190 // Make sure our primary file comes first
1191 let (primary_lo, sm) = if let (Some(sm), Some(ref primary_span)) =
1192 (self.sm.as_ref(), msp.primary_span().as_ref()) {
1193 if !primary_span.is_dummy() {
1194 (sm.lookup_char_pos(primary_span.lo()), sm)
1196 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1200 // If we don't have span information, emit and exit
1201 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1205 annotated_files.binary_search_by(|x| x.file.name.cmp(&primary_lo.file.name)) {
1206 annotated_files.swap(0, pos);
1209 // Print out the annotate source lines that correspond with the error
1210 for annotated_file in annotated_files {
1211 // we can't annotate anything if the source is unavailable.
1212 if !sm.ensure_source_file_source_present(annotated_file.file.clone()) {
1216 // print out the span location and spacer before we print the annotated source
1217 // to do this, we need to know if this span will be primary
1218 let is_primary = primary_lo.file.name == annotated_file.file.name;
1220 let loc = primary_lo.clone();
1221 if !self.short_message {
1222 // remember where we are in the output buffer for easy reference
1223 let buffer_msg_line_offset = buffer.num_lines();
1225 buffer.prepend(buffer_msg_line_offset, "--> ", Style::LineNumber);
1227 buffer_msg_line_offset,
1231 sm.doctest_offset_line(&loc.file.name, loc.line),
1234 Style::LineAndColumn,
1236 for _ in 0..max_line_num_len {
1237 buffer.prepend(buffer_msg_line_offset, " ", Style::NoStyle);
1245 sm.doctest_offset_line(&loc.file.name, loc.line),
1248 Style::LineAndColumn,
1251 } else if !self.short_message {
1252 // remember where we are in the output buffer for easy reference
1253 let buffer_msg_line_offset = buffer.num_lines();
1256 draw_col_separator(&mut buffer, buffer_msg_line_offset, max_line_num_len + 1);
1258 // Then, the secondary file indicator
1259 buffer.prepend(buffer_msg_line_offset + 1, "::: ", Style::LineNumber);
1260 let loc = if let Some(first_line) = annotated_file.lines.first() {
1261 let col = if let Some(first_annotation) = first_line.annotations.first() {
1262 format!(":{}", first_annotation.start_col + 1)
1267 annotated_file.file.name,
1268 sm.doctest_offset_line(
1269 &annotated_file.file.name, first_line.line_index),
1272 annotated_file.file.name.to_string()
1274 buffer.append(buffer_msg_line_offset + 1,
1276 Style::LineAndColumn);
1277 for _ in 0..max_line_num_len {
1278 buffer.prepend(buffer_msg_line_offset + 1, " ", Style::NoStyle);
1282 if !self.short_message {
1283 // Put in the spacer between the location and annotated source
1284 let buffer_msg_line_offset = buffer.num_lines();
1285 draw_col_separator_no_space(&mut buffer,
1286 buffer_msg_line_offset,
1287 max_line_num_len + 1);
1289 // Contains the vertical lines' positions for active multiline annotations
1290 let mut multilines = FxHashMap::default();
1292 // Get the left-side margin to remove it
1293 let mut whitespace_margin = std::usize::MAX;
1294 for line_idx in 0..annotated_file.lines.len() {
1295 let file = annotated_file.file.clone();
1296 let line = &annotated_file.lines[line_idx];
1297 if let Some(source_string) = file.get_line(line.line_index - 1) {
1298 let leading_whitespace = source_string
1300 .take_while(|c| c.is_whitespace())
1302 if source_string.chars().any(|c| !c.is_whitespace()) {
1303 whitespace_margin = min(
1310 if whitespace_margin == std::usize::MAX {
1311 whitespace_margin = 0;
1314 // Left-most column any visible span points at.
1315 let mut span_left_margin = std::usize::MAX;
1316 for line in &annotated_file.lines {
1317 for ann in &line.annotations {
1318 span_left_margin = min(span_left_margin, ann.start_col);
1319 span_left_margin = min(span_left_margin, ann.end_col);
1322 if span_left_margin == std::usize::MAX {
1323 span_left_margin = 0;
1326 // Right-most column any visible span points at.
1327 let mut span_right_margin = 0;
1328 let mut label_right_margin = 0;
1329 let mut max_line_len = 0;
1330 for line in &annotated_file.lines {
1331 max_line_len = max(max_line_len, annotated_file.file
1332 .get_line(line.line_index - 1)
1333 .map_or(0, |s| s.len()));
1334 for ann in &line.annotations {
1335 span_right_margin = max(span_right_margin, ann.start_col);
1336 span_right_margin = max(span_right_margin, ann.end_col);
1337 // FIXME: account for labels not in the same line
1338 let label_right = ann.label.as_ref().map_or(0, |l| l.len() + 1);
1339 label_right_margin = max(label_right_margin, ann.end_col + label_right);
1343 let width_offset = 3 + max_line_num_len;
1344 let code_offset = if annotated_file.multiline_depth == 0 {
1347 width_offset + annotated_file.multiline_depth + 1
1350 let column_width = if let Some(width) = self.terminal_width {
1351 width.saturating_sub(code_offset)
1352 } else if self.ui_testing {
1355 term_size::dimensions()
1356 .map(|(w, _)| w.saturating_sub(code_offset))
1357 .unwrap_or(std::usize::MAX)
1360 let margin = Margin::new(
1369 // Next, output the annotate source for this file
1370 for line_idx in 0..annotated_file.lines.len() {
1371 let previous_buffer_line = buffer.num_lines();
1373 let depths = self.render_source_line(
1375 annotated_file.file.clone(),
1376 &annotated_file.lines[line_idx],
1382 let mut to_add = FxHashMap::default();
1384 for (depth, style) in depths {
1385 if multilines.get(&depth).is_some() {
1386 multilines.remove(&depth);
1388 to_add.insert(depth, style);
1392 // Set the multiline annotation vertical lines to the left of
1393 // the code in this line.
1394 for (depth, style) in &multilines {
1395 for line in previous_buffer_line..buffer.num_lines() {
1396 draw_multiline_line(&mut buffer,
1403 // check to see if we need to print out or elide lines that come between
1404 // this annotated line and the next one.
1405 if line_idx < (annotated_file.lines.len() - 1) {
1406 let line_idx_delta = annotated_file.lines[line_idx + 1].line_index -
1407 annotated_file.lines[line_idx].line_index;
1408 if line_idx_delta > 2 {
1409 let last_buffer_line_num = buffer.num_lines();
1410 buffer.puts(last_buffer_line_num, 0, "...", Style::LineNumber);
1412 // Set the multiline annotation vertical lines on `...` bridging line.
1413 for (depth, style) in &multilines {
1414 draw_multiline_line(&mut buffer,
1415 last_buffer_line_num,
1420 } else if line_idx_delta == 2 {
1421 let unannotated_line = annotated_file.file
1422 .get_line(annotated_file.lines[line_idx].line_index)
1423 .unwrap_or_else(|| Cow::from(""));
1425 let last_buffer_line_num = buffer.num_lines();
1430 annotated_file.lines[line_idx + 1].line_index - 1,
1431 last_buffer_line_num,
1437 for (depth, style) in &multilines {
1438 draw_multiline_line(
1440 last_buffer_line_num,
1449 multilines.extend(&to_add);
1454 // final step: take our styled buffer, render it, then output it
1455 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1461 fn emit_suggestion_default(
1463 suggestion: &CodeSuggestion,
1465 max_line_num_len: usize,
1466 ) -> io::Result<()> {
1467 let sm = match self.sm {
1469 None => return Ok(())
1472 let mut buffer = StyledBuffer::new();
1474 // Render the suggestion message
1475 let level_str = level.to_string();
1476 if !level_str.is_empty() {
1477 buffer.append(0, &level_str, Style::Level(level.clone()));
1478 buffer.append(0, ": ", Style::HeaderMsg);
1482 &[(suggestion.msg.to_owned(), Style::NoStyle)],
1485 Some(Style::HeaderMsg),
1488 // Render the replacements for each suggestion
1489 let suggestions = suggestion.splice_lines(&**sm);
1491 let mut row_num = 2;
1492 let mut notice_capitalization = false;
1493 for (complete, parts, only_capitalization) in suggestions.iter().take(MAX_SUGGESTIONS) {
1494 notice_capitalization |= only_capitalization;
1495 // Only show underline if the suggestion spans a single line and doesn't cover the
1496 // entirety of the code output. If you have multiple replacements in the same line
1497 // of code, show the underline.
1498 let show_underline = !(parts.len() == 1
1499 && parts[0].snippet.trim() == complete.trim())
1500 && complete.lines().count() == 1;
1502 let lines = sm.span_to_lines(parts[0].span).unwrap();
1504 assert!(!lines.lines.is_empty());
1506 let line_start = sm.lookup_char_pos(parts[0].span.lo()).line;
1507 draw_col_separator_no_space(&mut buffer, 1, max_line_num_len + 1);
1508 let mut line_pos = 0;
1509 let mut lines = complete.lines();
1510 for line in lines.by_ref().take(MAX_HIGHLIGHT_LINES) {
1511 // Print the span column to avoid confusion
1512 buffer.puts(row_num,
1514 &self.maybe_anonymized(line_start + line_pos),
1516 // print the suggestion
1517 draw_col_separator(&mut buffer, row_num, max_line_num_len + 1);
1518 buffer.append(row_num, line, Style::NoStyle);
1523 // This offset and the ones below need to be signed to account for replacement code
1524 // that is shorter than the original code.
1525 let mut offset: isize = 0;
1526 // Only show an underline in the suggestions if the suggestion is not the
1527 // entirety of the code being shown and the displayed code is not multiline.
1529 draw_col_separator(&mut buffer, row_num, max_line_num_len + 1);
1531 let span_start_pos = sm.lookup_char_pos(part.span.lo()).col_display;
1532 let span_end_pos = sm.lookup_char_pos(part.span.hi()).col_display;
1534 // Do not underline the leading...
1535 let start = part.snippet.len()
1536 .saturating_sub(part.snippet.trim_start().len());
1537 // ...or trailing spaces. Account for substitutions containing unicode
1539 let sub_len: usize = part.snippet.trim().chars()
1540 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
1543 let underline_start = (span_start_pos + start) as isize + offset;
1544 let underline_end = (span_start_pos + start + sub_len) as isize + offset;
1545 for p in underline_start..underline_end {
1546 buffer.putc(row_num,
1547 max_line_num_len + 3 + p as usize,
1549 Style::UnderlinePrimary);
1551 // underline removals too
1552 if underline_start == underline_end {
1553 for p in underline_start-1..underline_start+1 {
1554 buffer.putc(row_num,
1555 max_line_num_len + 3 + p as usize,
1557 Style::UnderlineSecondary);
1561 // length of the code after substitution
1562 let full_sub_len = part.snippet.chars()
1563 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
1564 .sum::<usize>() as isize;
1566 // length of the code to be substituted
1567 let snippet_len = span_end_pos as isize - span_start_pos as isize;
1568 // For multiple substitutions, use the position *after* the previous
1569 // substitutions have happened.
1570 offset += full_sub_len - snippet_len;
1575 // if we elided some lines, add an ellipsis
1576 if lines.next().is_some() {
1577 buffer.puts(row_num, max_line_num_len - 1, "...", Style::LineNumber);
1578 } else if !show_underline {
1579 draw_col_separator_no_space(&mut buffer, row_num, max_line_num_len + 1);
1583 if suggestions.len() > MAX_SUGGESTIONS {
1584 let others = suggestions.len() - MAX_SUGGESTIONS;
1585 let msg = format!("and {} other candidate{}", others, pluralize!(others));
1586 buffer.puts(row_num, max_line_num_len + 3, &msg, Style::NoStyle);
1587 } else if notice_capitalization {
1588 let msg = "notice the capitalization difference";
1589 buffer.puts(row_num, max_line_num_len + 3, &msg, Style::NoStyle);
1591 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1595 fn emit_messages_default(
1598 message: &[(String, Style)],
1599 code: &Option<DiagnosticId>,
1601 children: &[SubDiagnostic],
1602 suggestions: &[CodeSuggestion],
1604 let max_line_num_len = if self.ui_testing {
1605 ANONYMIZED_LINE_NUM.len()
1607 self.get_max_line_num(span, children).to_string().len()
1610 match self.emit_message_default(span, message, code, level, max_line_num_len, false) {
1612 if !children.is_empty() || suggestions.iter().any(|s| {
1613 s.style != SuggestionStyle::CompletelyHidden
1615 let mut buffer = StyledBuffer::new();
1616 if !self.short_message {
1617 draw_col_separator_no_space(&mut buffer, 0, max_line_num_len + 1);
1619 match emit_to_destination(&buffer.render(), level, &mut self.dst,
1620 self.short_message) {
1622 Err(e) => panic!("failed to emit error: {}", e)
1625 if !self.short_message {
1626 for child in children {
1627 let span = child.render_span.as_ref().unwrap_or(&child.span);
1628 match self.emit_message_default(
1630 &child.styled_message(),
1636 Err(e) => panic!("failed to emit error: {}", e),
1640 for sugg in suggestions {
1641 if sugg.style == SuggestionStyle::CompletelyHidden {
1642 // do not display this suggestion, it is meant only for tools
1643 } else if sugg.style == SuggestionStyle::HideCodeAlways {
1644 match self.emit_message_default(
1646 &[(sugg.msg.to_owned(), Style::HeaderMsg)],
1652 Err(e) => panic!("failed to emit error: {}", e),
1656 match self.emit_suggestion_default(
1661 Err(e) => panic!("failed to emit error: {}", e),
1668 Err(e) => panic!("failed to emit error: {}", e),
1671 let mut dst = self.dst.writable();
1672 match writeln!(dst) {
1673 Err(e) => panic!("failed to emit error: {}", e),
1676 Err(e) => panic!("failed to emit error: {}", e),
1684 impl FileWithAnnotatedLines {
1685 /// Preprocess all the annotations so that they are grouped by file and by line number
1686 /// This helps us quickly iterate over the whole message (including secondary file spans)
1687 pub fn collect_annotations(
1689 source_map: &Option<Lrc<SourceMap>>
1690 ) -> Vec<FileWithAnnotatedLines> {
1691 fn add_annotation_to_file(file_vec: &mut Vec<FileWithAnnotatedLines>,
1692 file: Lrc<SourceFile>,
1696 for slot in file_vec.iter_mut() {
1697 // Look through each of our files for the one we're adding to
1698 if slot.file.name == file.name {
1699 // See if we already have a line for it
1700 for line_slot in &mut slot.lines {
1701 if line_slot.line_index == line_index {
1702 line_slot.annotations.push(ann);
1706 // We don't have a line yet, create one
1707 slot.lines.push(Line {
1709 annotations: vec![ann],
1715 // This is the first time we're seeing the file
1716 file_vec.push(FileWithAnnotatedLines {
1720 annotations: vec![ann],
1726 let mut output = vec![];
1727 let mut multiline_annotations = vec![];
1729 if let Some(ref sm) = source_map {
1730 for span_label in msp.span_labels() {
1731 if span_label.span.is_dummy() {
1735 let lo = sm.lookup_char_pos(span_label.span.lo());
1736 let mut hi = sm.lookup_char_pos(span_label.span.hi());
1738 // Watch out for "empty spans". If we get a span like 6..6, we
1739 // want to just display a `^` at 6, so convert that to
1740 // 6..7. This is degenerate input, but it's best to degrade
1741 // gracefully -- and the parser likes to supply a span like
1742 // that for EOF, in particular.
1744 if lo.col_display == hi.col_display && lo.line == hi.line {
1745 hi.col_display += 1;
1748 if lo.line != hi.line {
1749 let ml = MultilineAnnotation {
1751 line_start: lo.line,
1753 start_col: lo.col_display,
1754 end_col: hi.col_display,
1755 is_primary: span_label.is_primary,
1756 label: span_label.label,
1757 overlaps_exactly: false,
1759 multiline_annotations.push((lo.file, ml));
1761 let ann = Annotation {
1762 start_col: lo.col_display,
1763 end_col: hi.col_display,
1764 is_primary: span_label.is_primary,
1765 label: span_label.label,
1766 annotation_type: AnnotationType::Singleline,
1768 add_annotation_to_file(&mut output, lo.file, lo.line, ann);
1773 // Find overlapping multiline annotations, put them at different depths
1774 multiline_annotations.sort_by_key(|&(_, ref ml)| (ml.line_start, ml.line_end));
1775 for (_, ann) in multiline_annotations.clone() {
1776 for (_, a) in multiline_annotations.iter_mut() {
1777 // Move all other multiline annotations overlapping with this one
1778 // one level to the right.
1779 if !(ann.same_span(a)) &&
1780 num_overlap(ann.line_start, ann.line_end, a.line_start, a.line_end, true)
1783 } else if ann.same_span(a) && &ann != a {
1784 a.overlaps_exactly = true;
1791 let mut max_depth = 0; // max overlapping multiline spans
1792 for (file, ann) in multiline_annotations {
1793 max_depth = max(max_depth, ann.depth);
1794 let mut end_ann = ann.as_end();
1795 if !ann.overlaps_exactly {
1796 // avoid output like
1818 add_annotation_to_file(&mut output, file.clone(), ann.line_start, ann.as_start());
1819 // 4 is the minimum vertical length of a multiline span when presented: two lines
1820 // of code and two lines of underline. This is not true for the special case where
1821 // the beginning doesn't have an underline, but the current logic seems to be
1822 // working correctly.
1823 let middle = min(ann.line_start + 4, ann.line_end);
1824 for line in ann.line_start + 1..middle {
1825 // Every `|` that joins the beginning of the span (`___^`) to the end (`|__^`).
1826 add_annotation_to_file(&mut output, file.clone(), line, ann.as_line());
1828 let line_end = ann.line_end - 1;
1829 if middle < line_end {
1830 add_annotation_to_file(&mut output, file.clone(), line_end, ann.as_line());
1833 end_ann.annotation_type = AnnotationType::Singleline;
1835 add_annotation_to_file(&mut output, file, ann.line_end, end_ann);
1837 for file_vec in output.iter_mut() {
1838 file_vec.multiline_depth = max_depth;
1844 fn draw_col_separator(buffer: &mut StyledBuffer, line: usize, col: usize) {
1845 buffer.puts(line, col, "| ", Style::LineNumber);
1848 fn draw_col_separator_no_space(buffer: &mut StyledBuffer, line: usize, col: usize) {
1849 draw_col_separator_no_space_with_style(buffer, line, col, Style::LineNumber);
1852 fn draw_col_separator_no_space_with_style(buffer: &mut StyledBuffer,
1856 buffer.putc(line, col, '|', style);
1859 fn draw_range(buffer: &mut StyledBuffer, symbol: char, line: usize,
1860 col_from: usize, col_to: usize, style: Style) {
1861 for col in col_from..col_to {
1862 buffer.putc(line, col, symbol, style);
1866 fn draw_note_separator(buffer: &mut StyledBuffer, line: usize, col: usize) {
1867 buffer.puts(line, col, "= ", Style::LineNumber);
1870 fn draw_multiline_line(buffer: &mut StyledBuffer,
1876 buffer.putc(line, offset + depth - 1, '|', style);
1879 fn num_overlap(a_start: usize, a_end: usize, b_start: usize, b_end:usize, inclusive: bool) -> bool {
1880 let extra = if inclusive {
1885 (b_start..b_end + extra).contains(&a_start) ||
1886 (a_start..a_end + extra).contains(&b_start)
1888 fn overlaps(a1: &Annotation, a2: &Annotation, padding: usize) -> bool {
1889 num_overlap(a1.start_col, a1.end_col + padding, a2.start_col, a2.end_col, false)
1892 fn emit_to_destination(rendered_buffer: &[Vec<StyledString>],
1894 dst: &mut Destination,
1895 short_message: bool)
1899 let mut dst = dst.writable();
1901 // In order to prevent error message interleaving, where multiple error lines get intermixed
1902 // when multiple compiler processes error simultaneously, we emit errors with additional
1905 // On Unix systems, we write into a buffered terminal rather than directly to a terminal. When
1906 // the .flush() is called we take the buffer created from the buffered writes and write it at
1907 // one shot. Because the Unix systems use ANSI for the colors, which is a text-based styling
1908 // scheme, this buffered approach works and maintains the styling.
1910 // On Windows, styling happens through calls to a terminal API. This prevents us from using the
1911 // same buffering approach. Instead, we use a global Windows mutex, which we acquire long
1912 // enough to output the full error message, then we release.
1913 let _buffer_lock = lock::acquire_global_lock("rustc_errors");
1914 for (pos, line) in rendered_buffer.iter().enumerate() {
1916 dst.apply_style(lvl.clone(), part.style)?;
1917 write!(dst, "{}", part.text)?;
1920 if !short_message && (!lvl.is_failure_note() || pos != rendered_buffer.len() - 1) {
1928 pub enum Destination {
1929 Terminal(StandardStream),
1930 Buffered(BufferWriter),
1931 // The bool denotes whether we should be emitting ansi color codes or not
1932 Raw(Box<(dyn Write + Send)>, bool),
1935 pub enum WritableDst<'a> {
1936 Terminal(&'a mut StandardStream),
1937 Buffered(&'a mut BufferWriter, Buffer),
1938 Raw(&'a mut (dyn Write + Send)),
1939 ColoredRaw(Ansi<&'a mut (dyn Write + Send)>),
1943 fn from_stderr(color: ColorConfig) -> Destination {
1944 let choice = color.to_color_choice();
1945 // On Windows we'll be performing global synchronization on the entire
1946 // system for emitting rustc errors, so there's no need to buffer
1949 // On non-Windows we rely on the atomicity of `write` to ensure errors
1950 // don't get all jumbled up.
1952 Terminal(StandardStream::stderr(choice))
1954 Buffered(BufferWriter::stderr(choice))
1958 fn writable(&mut self) -> WritableDst<'_> {
1960 Destination::Terminal(ref mut t) => WritableDst::Terminal(t),
1961 Destination::Buffered(ref mut t) => {
1962 let buf = t.buffer();
1963 WritableDst::Buffered(t, buf)
1965 Destination::Raw(ref mut t, false) => WritableDst::Raw(t),
1966 Destination::Raw(ref mut t, true) => WritableDst::ColoredRaw(Ansi::new(t)),
1971 impl<'a> WritableDst<'a> {
1972 fn apply_style(&mut self, lvl: Level, style: Style) -> io::Result<()> {
1973 let mut spec = ColorSpec::new();
1975 Style::LineAndColumn => {}
1976 Style::LineNumber => {
1977 spec.set_bold(true);
1978 spec.set_intense(true);
1980 spec.set_fg(Some(Color::Cyan));
1982 spec.set_fg(Some(Color::Blue));
1985 Style::Quotation => {}
1986 Style::MainHeaderMsg => {
1987 spec.set_bold(true);
1989 spec.set_intense(true)
1990 .set_fg(Some(Color::White));
1993 Style::UnderlinePrimary | Style::LabelPrimary => {
1995 spec.set_bold(true);
1997 Style::UnderlineSecondary |
1998 Style::LabelSecondary => {
2002 spec.set_fg(Some(Color::Cyan));
2004 spec.set_fg(Some(Color::Blue));
2008 Style::NoStyle => {}
2009 Style::Level(lvl) => {
2011 spec.set_bold(true);
2013 Style::Highlight => {
2014 spec.set_bold(true);
2017 self.set_color(&spec)
2020 fn set_color(&mut self, color: &ColorSpec) -> io::Result<()> {
2022 WritableDst::Terminal(ref mut t) => t.set_color(color),
2023 WritableDst::Buffered(_, ref mut t) => t.set_color(color),
2024 WritableDst::ColoredRaw(ref mut t) => t.set_color(color),
2025 WritableDst::Raw(_) => Ok(())
2029 fn reset(&mut self) -> io::Result<()> {
2031 WritableDst::Terminal(ref mut t) => t.reset(),
2032 WritableDst::Buffered(_, ref mut t) => t.reset(),
2033 WritableDst::ColoredRaw(ref mut t) => t.reset(),
2034 WritableDst::Raw(_) => Ok(()),
2039 impl<'a> Write for WritableDst<'a> {
2040 fn write(&mut self, bytes: &[u8]) -> io::Result<usize> {
2042 WritableDst::Terminal(ref mut t) => t.write(bytes),
2043 WritableDst::Buffered(_, ref mut buf) => buf.write(bytes),
2044 WritableDst::Raw(ref mut w) => w.write(bytes),
2045 WritableDst::ColoredRaw(ref mut t) => t.write(bytes),
2049 fn flush(&mut self) -> io::Result<()> {
2051 WritableDst::Terminal(ref mut t) => t.flush(),
2052 WritableDst::Buffered(_, ref mut buf) => buf.flush(),
2053 WritableDst::Raw(ref mut w) => w.flush(),
2054 WritableDst::ColoredRaw(ref mut w) => w.flush(),
2059 impl<'a> Drop for WritableDst<'a> {
2060 fn drop(&mut self) {
2062 WritableDst::Buffered(ref mut dst, ref mut buf) => {
2063 drop(dst.print(buf));
2070 /// Whether the original and suggested code are visually similar enough to warrant extra wording.
2071 pub fn is_case_difference(sm: &SourceMap, suggested: &str, sp: Span) -> bool {
2072 // FIXME: this should probably be extended to also account for `FO0` → `FOO` and unicode.
2073 let found = sm.span_to_snippet(sp).unwrap();
2074 let ascii_confusables = &['c', 'f', 'i', 'k', 'o', 's', 'u', 'v', 'w', 'x', 'y', 'z'];
2075 // All the chars that differ in capitalization are confusable (above):
2076 let confusable = found.chars().zip(suggested.chars()).filter(|(f, s)| f != s).all(|(f, s)| {
2077 (ascii_confusables.contains(&f) || ascii_confusables.contains(&s))
2079 confusable && found.to_lowercase() == suggested.to_lowercase()
2080 // FIXME: We sometimes suggest the same thing we already have, which is a
2081 // bug, but be defensive against that here.
2082 && found != suggested