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};
15 Level, CodeSuggestion, Diagnostic, SubDiagnostic, pluralize,
16 SuggestionStyle, SourceMapper, SourceMapperDyn, DiagnosticId,
18 use crate::Level::Error;
19 use crate::snippet::{Annotation, AnnotationType, Line, MultilineAnnotation, StyledString, Style};
20 use crate::styled_buffer::StyledBuffer;
22 use rustc_data_structures::fx::FxHashMap;
23 use rustc_data_structures::sync::Lrc;
25 use std::io::prelude::*;
27 use std::cmp::{min, max, Reverse};
29 use termcolor::{StandardStream, ColorChoice, ColorSpec, BufferWriter, Ansi};
30 use termcolor::{WriteColor, Color, Buffer};
32 /// Describes the way the content of the `rendered` field of the json output is generated
33 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
34 pub enum HumanReadableErrorType {
36 AnnotateSnippet(ColorConfig),
40 impl HumanReadableErrorType {
41 /// Returns a (`short`, `color`) tuple
42 pub fn unzip(self) -> (bool, ColorConfig) {
44 HumanReadableErrorType::Default(cc) => (false, cc),
45 HumanReadableErrorType::Short(cc) => (true, cc),
46 HumanReadableErrorType::AnnotateSnippet(cc) => (false, cc),
51 dst: Box<dyn Write + Send>,
52 source_map: Option<Lrc<SourceMapperDyn>>,
54 terminal_width: Option<usize>,
55 external_macro_backtrace: bool,
57 let (short, color_config) = self.unzip();
58 let color = color_config.suggests_using_colors();
59 EmitterWriter::new(dst, source_map, short, teach, color, terminal_width,
60 external_macro_backtrace)
64 #[derive(Clone, Copy, Debug)]
66 /// The available whitespace in the left that can be consumed when centering.
67 pub whitespace_left: usize,
68 /// The column of the beginning of left-most span.
70 /// The column of the end of right-most span.
71 pub span_right: usize,
72 /// The beginning of the line to be displayed.
73 pub computed_left: usize,
74 /// The end of the line to be displayed.
75 pub computed_right: usize,
76 /// The current width of the terminal. 140 by default and in tests.
77 pub column_width: usize,
78 /// The end column of a span label, including the span. Doesn't account for labels not in the
79 /// same line as the span.
80 pub label_right: usize,
85 whitespace_left: usize,
92 // The 6 is padding to give a bit of room for `...` when displaying:
97 // 16 | ... fn foo(self) -> Self::Bar {
102 whitespace_left: whitespace_left.saturating_sub(6),
103 span_left: span_left.saturating_sub(6),
104 span_right: span_right + 6,
108 label_right: label_right + 6,
110 m.compute(max_line_len);
114 fn was_cut_left(&self) -> bool {
115 self.computed_left > 0
118 fn was_cut_right(&self, line_len: usize) -> bool {
119 let right = if self.computed_right == self.span_right ||
120 self.computed_right == self.label_right
122 // Account for the "..." padding given above. Otherwise we end up with code lines that
123 // do fit but end in "..." as if they were trimmed.
124 self.computed_right - 6
128 right < line_len && self.computed_left + self.column_width < line_len
131 fn compute(&mut self, max_line_len: usize) {
132 // When there's a lot of whitespace (>20), we want to trim it as it is useless.
133 self.computed_left = if self.whitespace_left > 20 {
134 self.whitespace_left - 16 // We want some padding.
138 // We want to show as much as possible, max_line_len is the right-most boundary for the
140 self.computed_right = max(max_line_len, self.computed_left);
142 if self.computed_right - self.computed_left > self.column_width {
143 // Trimming only whitespace isn't enough, let's get craftier.
144 if self.label_right - self.whitespace_left <= self.column_width {
145 // Attempt to fit the code window only trimming whitespace.
146 self.computed_left = self.whitespace_left;
147 self.computed_right = self.computed_left + self.column_width;
148 } else if self.label_right - self.span_left <= self.column_width {
149 // Attempt to fit the code window considering only the spans and labels.
150 let padding_left = (self.column_width - (self.label_right - self.span_left)) / 2;
151 self.computed_left = self.span_left.saturating_sub(padding_left);
152 self.computed_right = self.computed_left + self.column_width;
153 } else if self.span_right - self.span_left <= self.column_width {
154 // Attempt to fit the code window considering the spans and labels plus padding.
155 let padding_left = (self.column_width - (self.span_right - self.span_left)) / 5 * 2;
156 self.computed_left = self.span_left.saturating_sub(padding_left);
157 self.computed_right = self.computed_left + self.column_width;
158 } else { // Mostly give up but still don't show the full line.
159 self.computed_left = self.span_left;
160 self.computed_right = self.span_right;
165 fn left(&self, line_len: usize) -> usize {
166 min(self.computed_left, line_len)
169 fn right(&self, line_len: usize) -> usize {
170 if line_len.saturating_sub(self.computed_left) <= self.column_width {
173 min(line_len, self.computed_right)
178 const ANONYMIZED_LINE_NUM: &str = "LL";
180 /// Emitter trait for emitting errors.
182 /// Emit a structured diagnostic.
183 fn emit_diagnostic(&mut self, diag: &Diagnostic);
185 /// Emit a notification that an artifact has been output.
186 /// This is currently only supported for the JSON format,
187 /// other formats can, and will, simply ignore it.
188 fn emit_artifact_notification(&mut self, _path: &Path, _artifact_type: &str) {}
190 /// Checks if should show explanations about "rustc --explain"
191 fn should_show_explain(&self) -> bool {
195 fn source_map(&self) -> Option<&Lrc<SourceMapperDyn>>;
197 /// Formats the substitutions of the primary_span
199 /// The are a lot of conditions to this method, but in short:
201 /// * If the current `Diagnostic` has only one visible `CodeSuggestion`,
202 /// we format the `help` suggestion depending on the content of the
203 /// substitutions. In that case, we return the modified span only.
205 /// * If the current `Diagnostic` has multiple suggestions,
206 /// we return the original `primary_span` and the original suggestions.
207 fn primary_span_formatted<'a>(
209 diag: &'a Diagnostic,
210 ) -> (MultiSpan, &'a [CodeSuggestion]) {
211 let mut primary_span = diag.span.clone();
212 if let Some((sugg, rest)) = diag.suggestions.split_first() {
213 if rest.is_empty() &&
214 // ^ if there is only one suggestion
215 // don't display multi-suggestions as labels
216 sugg.substitutions.len() == 1 &&
217 // don't display multipart suggestions as labels
218 sugg.substitutions[0].parts.len() == 1 &&
219 // don't display long messages as labels
220 sugg.msg.split_whitespace().count() < 10 &&
221 // don't display multiline suggestions as labels
222 !sugg.substitutions[0].parts[0].snippet.contains('\n') &&
224 // when this style is set we want the suggestion to be a message, not inline
225 SuggestionStyle::HideCodeAlways,
226 // trivial suggestion for tooling's sake, never shown
227 SuggestionStyle::CompletelyHidden,
228 // subtle suggestion, never shown inline
229 SuggestionStyle::ShowAlways,
230 ].contains(&sugg.style)
232 let substitution = &sugg.substitutions[0].parts[0].snippet.trim();
233 let msg = if substitution.len() == 0 || sugg.style.hide_inline() {
234 // This substitution is only removal OR we explicitly don't want to show the
235 // code inline (`hide_inline`). Therefore, we don't show the substitution.
236 format!("help: {}", sugg.msg)
238 // Show the default suggestion text with the substitution
242 if self.source_map().map(|sm| is_case_difference(
245 sugg.substitutions[0].parts[0].span,
246 )).unwrap_or(false) {
247 " (notice the capitalization)"
254 primary_span.push_span_label(sugg.substitutions[0].parts[0].span, msg);
256 // We return only the modified primary_span
259 // if there are multiple suggestions, print them all in full
260 // to be consistent. We could try to figure out if we can
261 // make one (or the first one) inline, but that would give
262 // undue importance to a semi-random suggestion
263 (primary_span, &diag.suggestions)
266 (primary_span, &diag.suggestions)
270 // This does a small "fix" for multispans by looking to see if it can find any that
271 // point directly at <*macros>. Since these are often difficult to read, this
272 // will change the span to point at the use site.
273 fn fix_multispans_in_std_macros(&self,
274 source_map: &Option<Lrc<SourceMapperDyn>>,
275 span: &mut MultiSpan,
276 children: &mut Vec<SubDiagnostic>,
279 let mut spans_updated = self.fix_multispan_in_std_macros(source_map, span, backtrace);
280 for child in children.iter_mut() {
281 spans_updated |= self.fix_multispan_in_std_macros(
287 let msg = if level == &Error {
288 "this error originates in a macro outside of the current crate \
289 (in Nightly builds, run with -Z external-macro-backtrace \
290 for more info)".to_string()
292 "this warning originates in a macro outside of the current crate \
293 (in Nightly builds, run with -Z external-macro-backtrace \
294 for more info)".to_string()
298 children.push(SubDiagnostic {
304 span: MultiSpan::new(),
310 // This "fixes" MultiSpans that contain Spans that are pointing to locations inside of
311 // <*macros>. Since these locations are often difficult to read, we move these Spans from
312 // <*macros> to their corresponding use site.
313 fn fix_multispan_in_std_macros(&self,
314 source_map: &Option<Lrc<SourceMapperDyn>>,
315 span: &mut MultiSpan,
316 always_backtrace: bool) -> bool {
317 let sm = match source_map {
319 None => return false,
322 let mut before_after: Vec<(Span, Span)> = vec![];
323 let mut new_labels: Vec<(Span, String)> = vec![];
325 // First, find all the spans in <*macros> and point instead at their use site
326 for sp in span.primary_spans() {
330 let call_sp = sm.call_span_if_macro(*sp);
331 if call_sp != *sp && !always_backtrace {
332 before_after.push((*sp, call_sp));
334 let backtrace_len = sp.macro_backtrace().len();
335 for (i, trace) in sp.macro_backtrace().iter().rev().enumerate() {
336 // Only show macro locations that are local
337 // and display them like a span_note
338 if trace.def_site_span.is_dummy() {
341 if always_backtrace {
342 new_labels.push((trace.def_site_span,
343 format!("in this expansion of `{}`{}",
344 trace.macro_decl_name,
345 if backtrace_len > 2 {
346 // if backtrace_len == 1 it'll be pointed
347 // at by "in this macro invocation"
348 format!(" (#{})", i + 1)
353 // Check to make sure we're not in any <*macros>
354 if !sm.span_to_filename(trace.def_site_span).is_macros() &&
355 !trace.macro_decl_name.starts_with("desugaring of ") &&
356 !trace.macro_decl_name.starts_with("#[") ||
358 new_labels.push((trace.call_site,
359 format!("in this macro invocation{}",
360 if backtrace_len > 2 && always_backtrace {
361 // only specify order when the macro
362 // backtrace is multiple levels deep
363 format!(" (#{})", i + 1)
367 if !always_backtrace {
373 for (label_span, label_text) in new_labels {
374 span.push_span_label(label_span, label_text);
376 for sp_label in span.span_labels() {
377 if sp_label.span.is_dummy() {
380 if sm.span_to_filename(sp_label.span.clone()).is_macros() &&
383 let v = sp_label.span.macro_backtrace();
384 if let Some(use_site) = v.last() {
385 before_after.push((sp_label.span.clone(), use_site.call_site.clone()));
389 // After we have them, make sure we replace these 'bad' def sites with their use sites
390 let spans_updated = !before_after.is_empty();
391 for (before, after) in before_after {
392 span.replace(before, after);
399 impl Emitter for EmitterWriter {
400 fn source_map(&self) -> Option<&Lrc<SourceMapperDyn>> {
404 fn emit_diagnostic(&mut self, diag: &Diagnostic) {
405 let mut children = diag.children.clone();
406 let (mut primary_span, suggestions) = self.primary_span_formatted(&diag);
408 self.fix_multispans_in_std_macros(&self.sm,
412 self.external_macro_backtrace);
414 self.emit_messages_default(&diag.level,
415 &diag.styled_message(),
422 fn should_show_explain(&self) -> bool {
427 /// An emitter that does nothing when emitting a diagnostic.
428 pub struct SilentEmitter;
430 impl Emitter for SilentEmitter {
431 fn source_map(&self) -> Option<&Lrc<SourceMapperDyn>> { None }
432 fn emit_diagnostic(&mut self, _: &Diagnostic) {}
435 /// maximum number of lines we will print for each error; arbitrary.
436 pub const MAX_HIGHLIGHT_LINES: usize = 6;
437 /// maximum number of suggestions to be shown
439 /// Arbitrary, but taken from trait import suggestion limit
440 pub const MAX_SUGGESTIONS: usize = 4;
442 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
443 pub enum ColorConfig {
450 fn to_color_choice(self) -> ColorChoice {
452 ColorConfig::Always => {
453 if atty::is(atty::Stream::Stderr) {
456 ColorChoice::AlwaysAnsi
459 ColorConfig::Never => ColorChoice::Never,
460 ColorConfig::Auto if atty::is(atty::Stream::Stderr) => {
463 ColorConfig::Auto => ColorChoice::Never,
466 fn suggests_using_colors(self) -> bool {
468 | ColorConfig::Always
471 ColorConfig::Never => false,
476 /// Handles the writing of `HumanReadableErrorType::Default` and `HumanReadableErrorType::Short`
477 pub struct EmitterWriter {
479 sm: Option<Lrc<SourceMapperDyn>>,
483 terminal_width: Option<usize>,
485 external_macro_backtrace: bool,
489 pub struct FileWithAnnotatedLines {
490 pub file: Lrc<SourceFile>,
491 pub lines: Vec<Line>,
492 multiline_depth: usize,
497 color_config: ColorConfig,
498 source_map: Option<Lrc<SourceMapperDyn>>,
501 terminal_width: Option<usize>,
502 external_macro_backtrace: bool,
504 let dst = Destination::from_stderr(color_config);
512 external_macro_backtrace,
517 dst: Box<dyn Write + Send>,
518 source_map: Option<Lrc<SourceMapperDyn>>,
522 terminal_width: Option<usize>,
523 external_macro_backtrace: bool,
526 dst: Raw(dst, colored),
532 external_macro_backtrace,
536 pub fn ui_testing(mut self, ui_testing: bool) -> Self {
537 self.ui_testing = ui_testing;
541 fn maybe_anonymized(&self, line_num: usize) -> String {
543 ANONYMIZED_LINE_NUM.to_string()
551 buffer: &mut StyledBuffer,
559 let line_len = source_string.len();
560 // Create the source line we will highlight.
561 let left = margin.left(line_len);
562 let right = margin.right(line_len);
563 // On long lines, we strip the source line, accounting for unicode.
565 let code: String = source_string.chars().skip(left).take_while(|ch| {
566 // Make sure that the trimming on the right will fall within the terminal width.
567 // FIXME: `unicode_width` sometimes disagrees with terminals on how wide a `char` is.
568 // For now, just accept that sometimes the code line will be longer than desired.
569 let next = unicode_width::UnicodeWidthChar::width(*ch).unwrap_or(1);
570 if taken + next > right - left {
576 buffer.puts(line_offset, code_offset, &code, Style::Quotation);
577 if margin.was_cut_left() {
578 // We have stripped some code/whitespace from the beginning, make it clear.
579 buffer.puts(line_offset, code_offset, "...", Style::LineNumber);
581 if margin.was_cut_right(line_len) {
582 // We have stripped some code after the right-most span end, make it clear we did so.
583 buffer.puts(line_offset, code_offset + taken - 3, "...", Style::LineNumber);
585 buffer.puts(line_offset, 0, &self.maybe_anonymized(line_index), Style::LineNumber);
587 draw_col_separator(buffer, line_offset, width_offset - 2);
590 fn render_source_line(
592 buffer: &mut StyledBuffer,
593 file: Lrc<SourceFile>,
598 ) -> Vec<(usize, Style)> {
604 // | secondary span label
606 // ^^ ^ ^^^ ^^^^ ^^^ we don't care about code too far to the right of a span, we trim it
608 // | | | actual code found in your source code and the spans we use to mark it
609 // | | when there's too much wasted space to the left, trim it
610 // | vertical divider between the column number and the code
613 if line.line_index == 0 {
617 let source_string = match file.get_line(line.line_index - 1) {
619 None => return Vec::new(),
622 let line_offset = buffer.num_lines();
624 let left = margin.left(source_string.len()); // Left trim
625 // Account for unicode characters of width !=0 that were removed.
626 let left = source_string.chars().take(left)
627 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
640 // Special case when there's only one annotation involved, it is the start of a multiline
641 // span and there's no text at the beginning of the code line. Instead of doing the whole
650 // we simplify the output to:
656 if let [ann] = &line.annotations[..] {
657 if let AnnotationType::MultilineStart(depth) = ann.annotation_type {
658 if source_string.chars().take(ann.start_col).all(|c| c.is_whitespace()) {
659 let style = if ann.is_primary {
660 Style::UnderlinePrimary
662 Style::UnderlineSecondary
664 buffer.putc(line_offset, width_offset + depth - 1, '/', style);
665 return vec![(depth, style)];
670 // We want to display like this:
672 // vec.push(vec.pop().unwrap());
673 // --- ^^^ - previous borrow ends here
675 // | error occurs here
676 // previous borrow of `vec` occurs here
678 // But there are some weird edge cases to be aware of:
680 // vec.push(vec.pop().unwrap());
681 // -------- - previous borrow ends here
683 // |this makes no sense
684 // previous borrow of `vec` occurs here
686 // For this reason, we group the lines into "highlight lines"
687 // and "annotations lines", where the highlight lines have the `^`.
689 // Sort the annotations by (start, end col)
690 // The labels are reversed, sort and then reversed again.
691 // Consider a list of annotations (A1, A2, C1, C2, B1, B2) where
692 // the letter signifies the span. Here we are only sorting by the
693 // span and hence, the order of the elements with the same span will
694 // not change. On reversing the ordering (|a, b| but b.cmp(a)), you get
695 // (C1, C2, B1, B2, A1, A2). All the elements with the same span are
696 // still ordered first to last, but all the elements with different
697 // spans are ordered by their spans in last to first order. Last to
698 // first order is important, because the jiggly lines and | are on
699 // the left, so the rightmost span needs to be rendered first,
700 // otherwise the lines would end up needing to go over a message.
702 let mut annotations = line.annotations.clone();
703 annotations.sort_by_key(|a| Reverse(a.start_col));
705 // First, figure out where each label will be positioned.
707 // In the case where you have the following annotations:
709 // vec.push(vec.pop().unwrap());
710 // -------- - previous borrow ends here [C]
712 // |this makes no sense [B]
713 // previous borrow of `vec` occurs here [A]
715 // `annotations_position` will hold [(2, A), (1, B), (0, C)].
717 // We try, when possible, to stick the rightmost annotation at the end
718 // of the highlight line:
720 // vec.push(vec.pop().unwrap());
721 // --- --- - previous borrow ends here
723 // But sometimes that's not possible because one of the other
724 // annotations overlaps it. For example, from the test
725 // `span_overlap_label`, we have the following annotations
726 // (written on distinct lines for clarity):
732 // In this case, we can't stick the rightmost-most label on
733 // the highlight line, or we would get:
740 // which is totally weird. Instead we want:
748 // which is...less weird, at least. In fact, in general, if
749 // the rightmost span overlaps with any other span, we should
750 // use the "hang below" version, so we can at least make it
751 // clear where the span *starts*. There's an exception for this
752 // logic, when the labels do not have a message:
767 let mut annotations_position = vec![];
768 let mut line_len = 0;
770 for (i, annotation) in annotations.iter().enumerate() {
771 for (j, next) in annotations.iter().enumerate() {
772 if overlaps(next, annotation, 0) // This label overlaps with another one and both
773 && annotation.has_label() // take space (they have text and are not
774 && j > i // multiline lines).
775 && p == 0 // We're currently on the first line, move the label one line down
777 // If we're overlapping with an un-labelled annotation with the same span
778 // we can just merge them in the output
779 if next.start_col == annotation.start_col
780 && next.end_col == annotation.end_col
786 // This annotation needs a new line in the output.
791 annotations_position.push((p, annotation));
792 for (j, next) in annotations.iter().enumerate() {
794 let l = next.label.as_ref().map_or(0, |label| label.len() + 2);
795 if (overlaps(next, annotation, l) // Do not allow two labels to be in the same
796 // line if they overlap including padding, to
797 // avoid situations like:
804 && annotation.has_label() // Both labels must have some text, otherwise
805 && next.has_label()) // they are not overlapping.
806 // Do not add a new line if this annotation
807 // or the next are vertical line placeholders.
808 || (annotation.takes_space() // If either this or the next annotation is
809 && next.has_label()) // multiline start/end, move it to a new line
810 || (annotation.has_label() // so as not to overlap the orizontal lines.
811 && next.takes_space())
812 || (annotation.takes_space() && next.takes_space())
813 || (overlaps(next, annotation, l)
814 && next.end_col <= annotation.end_col
816 && p == 0) // Avoid #42595.
818 // This annotation needs a new line in the output.
824 line_len = max(line_len, p);
831 // If there are no annotations or the only annotations on this line are
832 // MultilineLine, then there's only code being shown, stop processing.
833 if line.annotations.iter().all(|a| a.is_line()) {
837 // Write the colunmn separator.
839 // After this we will have:
848 for pos in 0..=line_len {
849 draw_col_separator(buffer, line_offset + pos + 1, width_offset - 2);
850 buffer.putc(line_offset + pos + 1,
856 // Write the horizontal lines for multiline annotations
857 // (only the first and last lines need this).
859 // After this we will have:
868 for &(pos, annotation) in &annotations_position {
869 let style = if annotation.is_primary {
870 Style::UnderlinePrimary
872 Style::UnderlineSecondary
875 match annotation.annotation_type {
876 AnnotationType::MultilineStart(depth) |
877 AnnotationType::MultilineEnd(depth) => {
882 width_offset + depth,
883 code_offset + annotation.start_col - left,
888 buffer.set_style_range(
890 code_offset + annotation.start_col - left,
891 code_offset + annotation.end_col - left,
893 annotation.is_primary,
900 // Write the vertical lines for labels that are on a different line as the underline.
902 // After this we will have:
911 for &(pos, annotation) in &annotations_position {
912 let style = if annotation.is_primary {
913 Style::UnderlinePrimary
915 Style::UnderlineSecondary
919 if pos > 1 && (annotation.has_label() || annotation.takes_space()) {
920 for p in line_offset + 1..=line_offset + pos {
922 code_offset + annotation.start_col - margin.computed_left,
927 match annotation.annotation_type {
928 AnnotationType::MultilineStart(depth) => {
929 for p in line_offset + pos + 1..line_offset + line_len + 2 {
931 width_offset + depth - 1,
936 AnnotationType::MultilineEnd(depth) => {
937 for p in line_offset..=line_offset + pos {
939 width_offset + depth - 1,
948 // Write the labels on the annotations that actually have a label.
950 // After this we will have:
955 // | something about `foo`
959 for &(pos, annotation) in &annotations_position {
960 let style = if annotation.is_primary {
963 Style::LabelSecondary
965 let (pos, col) = if pos == 0 {
966 (pos + 1, (annotation.end_col + 1).saturating_sub(left))
968 (pos + 2, annotation.start_col.saturating_sub(left))
970 if let Some(ref label) = annotation.label {
971 buffer.puts(line_offset + pos, code_offset + col, &label, style);
975 // Sort from biggest span to smallest span so that smaller spans are
976 // represented in the output:
981 // | | something about `foo`
982 // | something about `fn foo()`
983 annotations_position.sort_by_key(|(_, ann)| {
984 // Decreasing order. When annotations share the same length, prefer `Primary`.
985 (Reverse(ann.len()), ann.is_primary)
988 // Write the underlines.
990 // After this we will have:
995 // | something about `foo`
999 for &(_, annotation) in &annotations_position {
1000 let (underline, style) = if annotation.is_primary {
1001 ('^', Style::UnderlinePrimary)
1003 ('-', Style::UnderlineSecondary)
1005 for p in annotation.start_col..annotation.end_col {
1008 (code_offset + p).saturating_sub(left),
1014 annotations_position.iter().filter_map(|&(_, annotation)| {
1015 match annotation.annotation_type {
1016 AnnotationType::MultilineStart(p) | AnnotationType::MultilineEnd(p) => {
1017 let style = if annotation.is_primary {
1020 Style::LabelSecondary
1027 }).collect::<Vec<_>>()
1030 fn get_multispan_max_line_num(&mut self, msp: &MultiSpan) -> usize {
1031 let sm = match self.sm {
1037 for primary_span in msp.primary_spans() {
1038 if !primary_span.is_dummy() {
1039 let hi = sm.lookup_char_pos(primary_span.hi());
1040 max = (hi.line).max(max);
1043 if !self.short_message {
1044 for span_label in msp.span_labels() {
1045 if !span_label.span.is_dummy() {
1046 let hi = sm.lookup_char_pos(span_label.span.hi());
1047 max = (hi.line).max(max);
1055 fn get_max_line_num(&mut self, span: &MultiSpan, children: &[SubDiagnostic]) -> usize {
1056 let primary = self.get_multispan_max_line_num(span);
1058 .map(|sub| self.get_multispan_max_line_num(&sub.span))
1064 /// Adds a left margin to every line but the first, given a padding length and the label being
1065 /// displayed, keeping the provided highlighting.
1066 fn msg_to_buffer(&self,
1067 buffer: &mut StyledBuffer,
1068 msg: &[(String, Style)],
1071 override_style: Option<Style>) {
1073 // The extra 5 ` ` is padding that's always needed to align to the `note: `:
1076 // --> file.rs:13:20
1081 // = note: multiline
1086 // | | length of label
1088 // `max_line_num_len`
1089 let padding = " ".repeat(padding + label.len() + 5);
1091 /// Returns `override` if it is present and `style` is `NoStyle` or `style` otherwise
1092 fn style_or_override(style: Style, override_: Option<Style>) -> Style {
1093 match (style, override_) {
1094 (Style::NoStyle, Some(override_)) => override_,
1099 let mut line_number = 0;
1101 // Provided the following diagnostic message:
1105 // ("highlighted multiline\nstring to\nsee how it ", Style::NoStyle),
1106 // ("looks", Style::Highlight),
1107 // ("with\nvery ", Style::NoStyle),
1108 // ("weird", Style::Highlight),
1109 // (" formats\n", Style::NoStyle),
1110 // ("see?", Style::Highlight),
1113 // the expected output on a note is (* surround the highlighted text)
1115 // = note: highlighted multiline
1117 // see how it *looks* with
1118 // very *weird* formats
1120 for &(ref text, ref style) in msg.iter() {
1121 let lines = text.split('\n').collect::<Vec<_>>();
1122 if lines.len() > 1 {
1123 for (i, line) in lines.iter().enumerate() {
1126 buffer.append(line_number, &padding, Style::NoStyle);
1128 buffer.append(line_number, line, style_or_override(*style, override_style));
1131 buffer.append(line_number, text, style_or_override(*style, override_style));
1136 fn emit_message_default(
1139 msg: &[(String, Style)],
1140 code: &Option<DiagnosticId>,
1142 max_line_num_len: usize,
1144 ) -> io::Result<()> {
1145 let mut buffer = StyledBuffer::new();
1146 let header_style = if is_secondary {
1149 Style::MainHeaderMsg
1152 if !msp.has_primary_spans() && !msp.has_span_labels() && is_secondary
1153 && !self.short_message {
1154 // This is a secondary message with no span info
1155 for _ in 0..max_line_num_len {
1156 buffer.prepend(0, " ", Style::NoStyle);
1158 draw_note_separator(&mut buffer, 0, max_line_num_len + 1);
1159 if *level != Level::FailureNote {
1160 let level_str = level.to_string();
1161 if !level_str.is_empty() {
1162 buffer.append(0, &level_str, Style::MainHeaderMsg);
1163 buffer.append(0, ": ", Style::NoStyle);
1166 self.msg_to_buffer(&mut buffer, msg, max_line_num_len, "note", None);
1168 let level_str = level.to_string();
1169 // The failure note level itself does not provide any useful diagnostic information
1170 if *level != Level::FailureNote && !level_str.is_empty() {
1171 buffer.append(0, &level_str, Style::Level(level.clone()));
1173 // only render error codes, not lint codes
1174 if let Some(DiagnosticId::Error(ref code)) = *code {
1175 buffer.append(0, "[", Style::Level(level.clone()));
1176 buffer.append(0, &code, Style::Level(level.clone()));
1177 buffer.append(0, "]", Style::Level(level.clone()));
1179 if *level != Level::FailureNote && !level_str.is_empty() {
1180 buffer.append(0, ": ", header_style);
1182 for &(ref text, _) in msg.iter() {
1183 buffer.append(0, text, header_style);
1187 let mut annotated_files = FileWithAnnotatedLines::collect_annotations(msp, &self.sm);
1189 // Make sure our primary file comes first
1190 let (primary_lo, sm) = if let (Some(sm), Some(ref primary_span)) =
1191 (self.sm.as_ref(), msp.primary_span().as_ref()) {
1192 if !primary_span.is_dummy() {
1193 (sm.lookup_char_pos(primary_span.lo()), sm)
1195 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1199 // If we don't have span information, emit and exit
1200 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1204 annotated_files.binary_search_by(|x| x.file.name.cmp(&primary_lo.file.name)) {
1205 annotated_files.swap(0, pos);
1208 // Print out the annotate source lines that correspond with the error
1209 for annotated_file in annotated_files {
1210 // we can't annotate anything if the source is unavailable.
1211 if !sm.ensure_source_file_source_present(annotated_file.file.clone()) {
1215 // print out the span location and spacer before we print the annotated source
1216 // to do this, we need to know if this span will be primary
1217 let is_primary = primary_lo.file.name == annotated_file.file.name;
1219 let loc = primary_lo.clone();
1220 if !self.short_message {
1221 // remember where we are in the output buffer for easy reference
1222 let buffer_msg_line_offset = buffer.num_lines();
1224 buffer.prepend(buffer_msg_line_offset, "--> ", Style::LineNumber);
1226 buffer_msg_line_offset,
1230 sm.doctest_offset_line(&loc.file.name, loc.line),
1233 Style::LineAndColumn,
1235 for _ in 0..max_line_num_len {
1236 buffer.prepend(buffer_msg_line_offset, " ", Style::NoStyle);
1244 sm.doctest_offset_line(&loc.file.name, loc.line),
1247 Style::LineAndColumn,
1250 } else if !self.short_message {
1251 // remember where we are in the output buffer for easy reference
1252 let buffer_msg_line_offset = buffer.num_lines();
1255 draw_col_separator(&mut buffer, buffer_msg_line_offset, max_line_num_len + 1);
1257 // Then, the secondary file indicator
1258 buffer.prepend(buffer_msg_line_offset + 1, "::: ", Style::LineNumber);
1259 let loc = if let Some(first_line) = annotated_file.lines.first() {
1260 let col = if let Some(first_annotation) = first_line.annotations.first() {
1261 format!(":{}", first_annotation.start_col + 1)
1266 annotated_file.file.name,
1267 sm.doctest_offset_line(
1268 &annotated_file.file.name, first_line.line_index),
1271 annotated_file.file.name.to_string()
1273 buffer.append(buffer_msg_line_offset + 1,
1275 Style::LineAndColumn);
1276 for _ in 0..max_line_num_len {
1277 buffer.prepend(buffer_msg_line_offset + 1, " ", Style::NoStyle);
1281 if !self.short_message {
1282 // Put in the spacer between the location and annotated source
1283 let buffer_msg_line_offset = buffer.num_lines();
1284 draw_col_separator_no_space(&mut buffer,
1285 buffer_msg_line_offset,
1286 max_line_num_len + 1);
1288 // Contains the vertical lines' positions for active multiline annotations
1289 let mut multilines = FxHashMap::default();
1291 // Get the left-side margin to remove it
1292 let mut whitespace_margin = std::usize::MAX;
1293 for line_idx in 0..annotated_file.lines.len() {
1294 let file = annotated_file.file.clone();
1295 let line = &annotated_file.lines[line_idx];
1296 if let Some(source_string) = file.get_line(line.line_index - 1) {
1297 let leading_whitespace = source_string
1299 .take_while(|c| c.is_whitespace())
1301 if source_string.chars().any(|c| !c.is_whitespace()) {
1302 whitespace_margin = min(
1309 if whitespace_margin == std::usize::MAX {
1310 whitespace_margin = 0;
1313 // Left-most column any visible span points at.
1314 let mut span_left_margin = std::usize::MAX;
1315 for line in &annotated_file.lines {
1316 for ann in &line.annotations {
1317 span_left_margin = min(span_left_margin, ann.start_col);
1318 span_left_margin = min(span_left_margin, ann.end_col);
1321 if span_left_margin == std::usize::MAX {
1322 span_left_margin = 0;
1325 // Right-most column any visible span points at.
1326 let mut span_right_margin = 0;
1327 let mut label_right_margin = 0;
1328 let mut max_line_len = 0;
1329 for line in &annotated_file.lines {
1330 max_line_len = max(max_line_len, annotated_file.file
1331 .get_line(line.line_index - 1)
1332 .map_or(0, |s| s.len()));
1333 for ann in &line.annotations {
1334 span_right_margin = max(span_right_margin, ann.start_col);
1335 span_right_margin = max(span_right_margin, ann.end_col);
1336 // FIXME: account for labels not in the same line
1337 let label_right = ann.label.as_ref().map_or(0, |l| l.len() + 1);
1338 label_right_margin = max(label_right_margin, ann.end_col + label_right);
1342 let width_offset = 3 + max_line_num_len;
1343 let code_offset = if annotated_file.multiline_depth == 0 {
1346 width_offset + annotated_file.multiline_depth + 1
1349 let column_width = if let Some(width) = self.terminal_width {
1350 width.saturating_sub(code_offset)
1351 } else if self.ui_testing {
1354 term_size::dimensions()
1355 .map(|(w, _)| w.saturating_sub(code_offset))
1356 .unwrap_or(std::usize::MAX)
1359 let margin = Margin::new(
1368 // Next, output the annotate source for this file
1369 for line_idx in 0..annotated_file.lines.len() {
1370 let previous_buffer_line = buffer.num_lines();
1372 let depths = self.render_source_line(
1374 annotated_file.file.clone(),
1375 &annotated_file.lines[line_idx],
1381 let mut to_add = FxHashMap::default();
1383 for (depth, style) in depths {
1384 if multilines.get(&depth).is_some() {
1385 multilines.remove(&depth);
1387 to_add.insert(depth, style);
1391 // Set the multiline annotation vertical lines to the left of
1392 // the code in this line.
1393 for (depth, style) in &multilines {
1394 for line in previous_buffer_line..buffer.num_lines() {
1395 draw_multiline_line(&mut buffer,
1402 // check to see if we need to print out or elide lines that come between
1403 // this annotated line and the next one.
1404 if line_idx < (annotated_file.lines.len() - 1) {
1405 let line_idx_delta = annotated_file.lines[line_idx + 1].line_index -
1406 annotated_file.lines[line_idx].line_index;
1407 if line_idx_delta > 2 {
1408 let last_buffer_line_num = buffer.num_lines();
1409 buffer.puts(last_buffer_line_num, 0, "...", Style::LineNumber);
1411 // Set the multiline annotation vertical lines on `...` bridging line.
1412 for (depth, style) in &multilines {
1413 draw_multiline_line(&mut buffer,
1414 last_buffer_line_num,
1419 } else if line_idx_delta == 2 {
1420 let unannotated_line = annotated_file.file
1421 .get_line(annotated_file.lines[line_idx].line_index)
1422 .unwrap_or_else(|| Cow::from(""));
1424 let last_buffer_line_num = buffer.num_lines();
1429 annotated_file.lines[line_idx + 1].line_index - 1,
1430 last_buffer_line_num,
1436 for (depth, style) in &multilines {
1437 draw_multiline_line(
1439 last_buffer_line_num,
1448 multilines.extend(&to_add);
1453 // final step: take our styled buffer, render it, then output it
1454 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1460 fn emit_suggestion_default(
1462 suggestion: &CodeSuggestion,
1464 max_line_num_len: usize,
1465 ) -> io::Result<()> {
1466 let sm = match self.sm {
1468 None => return Ok(())
1471 let mut buffer = StyledBuffer::new();
1473 // Render the suggestion message
1474 let level_str = level.to_string();
1475 if !level_str.is_empty() {
1476 buffer.append(0, &level_str, Style::Level(level.clone()));
1477 buffer.append(0, ": ", Style::HeaderMsg);
1481 &[(suggestion.msg.to_owned(), Style::NoStyle)],
1484 Some(Style::HeaderMsg),
1487 // Render the replacements for each suggestion
1488 let suggestions = suggestion.splice_lines(&**sm);
1490 let mut row_num = 2;
1491 let mut notice_capitalization = false;
1492 for (complete, parts, only_capitalization) in suggestions.iter().take(MAX_SUGGESTIONS) {
1493 notice_capitalization |= only_capitalization;
1494 // Only show underline if the suggestion spans a single line and doesn't cover the
1495 // entirety of the code output. If you have multiple replacements in the same line
1496 // of code, show the underline.
1497 let show_underline = !(parts.len() == 1
1498 && parts[0].snippet.trim() == complete.trim())
1499 && complete.lines().count() == 1;
1501 let lines = sm.span_to_lines(parts[0].span).unwrap();
1503 assert!(!lines.lines.is_empty());
1505 let line_start = sm.lookup_char_pos(parts[0].span.lo()).line;
1506 draw_col_separator_no_space(&mut buffer, 1, max_line_num_len + 1);
1507 let mut line_pos = 0;
1508 let mut lines = complete.lines();
1509 for line in lines.by_ref().take(MAX_HIGHLIGHT_LINES) {
1510 // Print the span column to avoid confusion
1511 buffer.puts(row_num,
1513 &self.maybe_anonymized(line_start + line_pos),
1515 // print the suggestion
1516 draw_col_separator(&mut buffer, row_num, max_line_num_len + 1);
1517 buffer.append(row_num, line, Style::NoStyle);
1522 // This offset and the ones below need to be signed to account for replacement code
1523 // that is shorter than the original code.
1524 let mut offset: isize = 0;
1525 // Only show an underline in the suggestions if the suggestion is not the
1526 // entirety of the code being shown and the displayed code is not multiline.
1528 draw_col_separator(&mut buffer, row_num, max_line_num_len + 1);
1530 let span_start_pos = sm.lookup_char_pos(part.span.lo()).col_display;
1531 let span_end_pos = sm.lookup_char_pos(part.span.hi()).col_display;
1533 // Do not underline the leading...
1534 let start = part.snippet.len()
1535 .saturating_sub(part.snippet.trim_start().len());
1536 // ...or trailing spaces. Account for substitutions containing unicode
1538 let sub_len: usize = part.snippet.trim().chars()
1539 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
1542 let underline_start = (span_start_pos + start) as isize + offset;
1543 let underline_end = (span_start_pos + start + sub_len) as isize + offset;
1544 for p in underline_start..underline_end {
1545 buffer.putc(row_num,
1546 max_line_num_len + 3 + p as usize,
1548 Style::UnderlinePrimary);
1550 // underline removals too
1551 if underline_start == underline_end {
1552 for p in underline_start-1..underline_start+1 {
1553 buffer.putc(row_num,
1554 max_line_num_len + 3 + p as usize,
1556 Style::UnderlineSecondary);
1560 // length of the code after substitution
1561 let full_sub_len = part.snippet.chars()
1562 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
1563 .sum::<usize>() as isize;
1565 // length of the code to be substituted
1566 let snippet_len = span_end_pos as isize - span_start_pos as isize;
1567 // For multiple substitutions, use the position *after* the previous
1568 // substitutions have happened.
1569 offset += full_sub_len - snippet_len;
1574 // if we elided some lines, add an ellipsis
1575 if lines.next().is_some() {
1576 buffer.puts(row_num, max_line_num_len - 1, "...", Style::LineNumber);
1577 } else if !show_underline {
1578 draw_col_separator_no_space(&mut buffer, row_num, max_line_num_len + 1);
1582 if suggestions.len() > MAX_SUGGESTIONS {
1583 let others = suggestions.len() - MAX_SUGGESTIONS;
1584 let msg = format!("and {} other candidate{}", others, pluralize!(others));
1585 buffer.puts(row_num, max_line_num_len + 3, &msg, Style::NoStyle);
1586 } else if notice_capitalization {
1587 let msg = "notice the capitalization difference";
1588 buffer.puts(row_num, max_line_num_len + 3, &msg, Style::NoStyle);
1590 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1594 fn emit_messages_default(
1597 message: &[(String, Style)],
1598 code: &Option<DiagnosticId>,
1600 children: &[SubDiagnostic],
1601 suggestions: &[CodeSuggestion],
1603 let max_line_num_len = if self.ui_testing {
1604 ANONYMIZED_LINE_NUM.len()
1606 self.get_max_line_num(span, children).to_string().len()
1609 match self.emit_message_default(span, message, code, level, max_line_num_len, false) {
1611 if !children.is_empty() || suggestions.iter().any(|s| {
1612 s.style != SuggestionStyle::CompletelyHidden
1614 let mut buffer = StyledBuffer::new();
1615 if !self.short_message {
1616 draw_col_separator_no_space(&mut buffer, 0, max_line_num_len + 1);
1618 match emit_to_destination(&buffer.render(), level, &mut self.dst,
1619 self.short_message) {
1621 Err(e) => panic!("failed to emit error: {}", e)
1624 if !self.short_message {
1625 for child in children {
1626 let span = child.render_span.as_ref().unwrap_or(&child.span);
1627 match self.emit_message_default(
1629 &child.styled_message(),
1635 Err(e) => panic!("failed to emit error: {}", e),
1639 for sugg in suggestions {
1640 if sugg.style == SuggestionStyle::CompletelyHidden {
1641 // do not display this suggestion, it is meant only for tools
1642 } else if sugg.style == SuggestionStyle::HideCodeAlways {
1643 match self.emit_message_default(
1645 &[(sugg.msg.to_owned(), Style::HeaderMsg)],
1651 Err(e) => panic!("failed to emit error: {}", e),
1655 match self.emit_suggestion_default(
1660 Err(e) => panic!("failed to emit error: {}", e),
1667 Err(e) => panic!("failed to emit error: {}", e),
1670 let mut dst = self.dst.writable();
1671 match writeln!(dst) {
1672 Err(e) => panic!("failed to emit error: {}", e),
1675 Err(e) => panic!("failed to emit error: {}", e),
1683 impl FileWithAnnotatedLines {
1684 /// Preprocess all the annotations so that they are grouped by file and by line number
1685 /// This helps us quickly iterate over the whole message (including secondary file spans)
1686 pub fn collect_annotations(
1688 source_map: &Option<Lrc<SourceMapperDyn>>
1689 ) -> Vec<FileWithAnnotatedLines> {
1690 fn add_annotation_to_file(file_vec: &mut Vec<FileWithAnnotatedLines>,
1691 file: Lrc<SourceFile>,
1695 for slot in file_vec.iter_mut() {
1696 // Look through each of our files for the one we're adding to
1697 if slot.file.name == file.name {
1698 // See if we already have a line for it
1699 for line_slot in &mut slot.lines {
1700 if line_slot.line_index == line_index {
1701 line_slot.annotations.push(ann);
1705 // We don't have a line yet, create one
1706 slot.lines.push(Line {
1708 annotations: vec![ann],
1714 // This is the first time we're seeing the file
1715 file_vec.push(FileWithAnnotatedLines {
1719 annotations: vec![ann],
1725 let mut output = vec![];
1726 let mut multiline_annotations = vec![];
1728 if let Some(ref sm) = source_map {
1729 for span_label in msp.span_labels() {
1730 if span_label.span.is_dummy() {
1734 let lo = sm.lookup_char_pos(span_label.span.lo());
1735 let mut hi = sm.lookup_char_pos(span_label.span.hi());
1737 // Watch out for "empty spans". If we get a span like 6..6, we
1738 // want to just display a `^` at 6, so convert that to
1739 // 6..7. This is degenerate input, but it's best to degrade
1740 // gracefully -- and the parser likes to supply a span like
1741 // that for EOF, in particular.
1743 if lo.col_display == hi.col_display && lo.line == hi.line {
1744 hi.col_display += 1;
1747 if lo.line != hi.line {
1748 let ml = MultilineAnnotation {
1750 line_start: lo.line,
1752 start_col: lo.col_display,
1753 end_col: hi.col_display,
1754 is_primary: span_label.is_primary,
1755 label: span_label.label,
1756 overlaps_exactly: false,
1758 multiline_annotations.push((lo.file, ml));
1760 let ann = Annotation {
1761 start_col: lo.col_display,
1762 end_col: hi.col_display,
1763 is_primary: span_label.is_primary,
1764 label: span_label.label,
1765 annotation_type: AnnotationType::Singleline,
1767 add_annotation_to_file(&mut output, lo.file, lo.line, ann);
1772 // Find overlapping multiline annotations, put them at different depths
1773 multiline_annotations.sort_by_key(|&(_, ref ml)| (ml.line_start, ml.line_end));
1774 for (_, ann) in multiline_annotations.clone() {
1775 for (_, a) in multiline_annotations.iter_mut() {
1776 // Move all other multiline annotations overlapping with this one
1777 // one level to the right.
1778 if !(ann.same_span(a)) &&
1779 num_overlap(ann.line_start, ann.line_end, a.line_start, a.line_end, true)
1782 } else if ann.same_span(a) && &ann != a {
1783 a.overlaps_exactly = true;
1790 let mut max_depth = 0; // max overlapping multiline spans
1791 for (file, ann) in multiline_annotations {
1792 max_depth = max(max_depth, ann.depth);
1793 let mut end_ann = ann.as_end();
1794 if !ann.overlaps_exactly {
1795 // avoid output like
1817 add_annotation_to_file(&mut output, file.clone(), ann.line_start, ann.as_start());
1818 // 4 is the minimum vertical length of a multiline span when presented: two lines
1819 // of code and two lines of underline. This is not true for the special case where
1820 // the beginning doesn't have an underline, but the current logic seems to be
1821 // working correctly.
1822 let middle = min(ann.line_start + 4, ann.line_end);
1823 for line in ann.line_start + 1..middle {
1824 // Every `|` that joins the beginning of the span (`___^`) to the end (`|__^`).
1825 add_annotation_to_file(&mut output, file.clone(), line, ann.as_line());
1827 let line_end = ann.line_end - 1;
1828 if middle < line_end {
1829 add_annotation_to_file(&mut output, file.clone(), line_end, ann.as_line());
1832 end_ann.annotation_type = AnnotationType::Singleline;
1834 add_annotation_to_file(&mut output, file, ann.line_end, end_ann);
1836 for file_vec in output.iter_mut() {
1837 file_vec.multiline_depth = max_depth;
1843 fn draw_col_separator(buffer: &mut StyledBuffer, line: usize, col: usize) {
1844 buffer.puts(line, col, "| ", Style::LineNumber);
1847 fn draw_col_separator_no_space(buffer: &mut StyledBuffer, line: usize, col: usize) {
1848 draw_col_separator_no_space_with_style(buffer, line, col, Style::LineNumber);
1851 fn draw_col_separator_no_space_with_style(buffer: &mut StyledBuffer,
1855 buffer.putc(line, col, '|', style);
1858 fn draw_range(buffer: &mut StyledBuffer, symbol: char, line: usize,
1859 col_from: usize, col_to: usize, style: Style) {
1860 for col in col_from..col_to {
1861 buffer.putc(line, col, symbol, style);
1865 fn draw_note_separator(buffer: &mut StyledBuffer, line: usize, col: usize) {
1866 buffer.puts(line, col, "= ", Style::LineNumber);
1869 fn draw_multiline_line(buffer: &mut StyledBuffer,
1875 buffer.putc(line, offset + depth - 1, '|', style);
1878 fn num_overlap(a_start: usize, a_end: usize, b_start: usize, b_end:usize, inclusive: bool) -> bool {
1879 let extra = if inclusive {
1884 (b_start..b_end + extra).contains(&a_start) ||
1885 (a_start..a_end + extra).contains(&b_start)
1887 fn overlaps(a1: &Annotation, a2: &Annotation, padding: usize) -> bool {
1888 num_overlap(a1.start_col, a1.end_col + padding, a2.start_col, a2.end_col, false)
1891 fn emit_to_destination(rendered_buffer: &[Vec<StyledString>],
1893 dst: &mut Destination,
1894 short_message: bool)
1898 let mut dst = dst.writable();
1900 // In order to prevent error message interleaving, where multiple error lines get intermixed
1901 // when multiple compiler processes error simultaneously, we emit errors with additional
1904 // On Unix systems, we write into a buffered terminal rather than directly to a terminal. When
1905 // the .flush() is called we take the buffer created from the buffered writes and write it at
1906 // one shot. Because the Unix systems use ANSI for the colors, which is a text-based styling
1907 // scheme, this buffered approach works and maintains the styling.
1909 // On Windows, styling happens through calls to a terminal API. This prevents us from using the
1910 // same buffering approach. Instead, we use a global Windows mutex, which we acquire long
1911 // enough to output the full error message, then we release.
1912 let _buffer_lock = lock::acquire_global_lock("rustc_errors");
1913 for (pos, line) in rendered_buffer.iter().enumerate() {
1915 dst.apply_style(lvl.clone(), part.style)?;
1916 write!(dst, "{}", part.text)?;
1919 if !short_message && (!lvl.is_failure_note() || pos != rendered_buffer.len() - 1) {
1927 pub enum Destination {
1928 Terminal(StandardStream),
1929 Buffered(BufferWriter),
1930 // The bool denotes whether we should be emitting ansi color codes or not
1931 Raw(Box<(dyn Write + Send)>, bool),
1934 pub enum WritableDst<'a> {
1935 Terminal(&'a mut StandardStream),
1936 Buffered(&'a mut BufferWriter, Buffer),
1937 Raw(&'a mut (dyn Write + Send)),
1938 ColoredRaw(Ansi<&'a mut (dyn Write + Send)>),
1942 fn from_stderr(color: ColorConfig) -> Destination {
1943 let choice = color.to_color_choice();
1944 // On Windows we'll be performing global synchronization on the entire
1945 // system for emitting rustc errors, so there's no need to buffer
1948 // On non-Windows we rely on the atomicity of `write` to ensure errors
1949 // don't get all jumbled up.
1951 Terminal(StandardStream::stderr(choice))
1953 Buffered(BufferWriter::stderr(choice))
1957 fn writable(&mut self) -> WritableDst<'_> {
1959 Destination::Terminal(ref mut t) => WritableDst::Terminal(t),
1960 Destination::Buffered(ref mut t) => {
1961 let buf = t.buffer();
1962 WritableDst::Buffered(t, buf)
1964 Destination::Raw(ref mut t, false) => WritableDst::Raw(t),
1965 Destination::Raw(ref mut t, true) => WritableDst::ColoredRaw(Ansi::new(t)),
1970 impl<'a> WritableDst<'a> {
1971 fn apply_style(&mut self, lvl: Level, style: Style) -> io::Result<()> {
1972 let mut spec = ColorSpec::new();
1974 Style::LineAndColumn => {}
1975 Style::LineNumber => {
1976 spec.set_bold(true);
1977 spec.set_intense(true);
1979 spec.set_fg(Some(Color::Cyan));
1981 spec.set_fg(Some(Color::Blue));
1984 Style::Quotation => {}
1985 Style::MainHeaderMsg => {
1986 spec.set_bold(true);
1988 spec.set_intense(true)
1989 .set_fg(Some(Color::White));
1992 Style::UnderlinePrimary | Style::LabelPrimary => {
1994 spec.set_bold(true);
1996 Style::UnderlineSecondary |
1997 Style::LabelSecondary => {
2001 spec.set_fg(Some(Color::Cyan));
2003 spec.set_fg(Some(Color::Blue));
2007 Style::NoStyle => {}
2008 Style::Level(lvl) => {
2010 spec.set_bold(true);
2012 Style::Highlight => {
2013 spec.set_bold(true);
2016 self.set_color(&spec)
2019 fn set_color(&mut self, color: &ColorSpec) -> io::Result<()> {
2021 WritableDst::Terminal(ref mut t) => t.set_color(color),
2022 WritableDst::Buffered(_, ref mut t) => t.set_color(color),
2023 WritableDst::ColoredRaw(ref mut t) => t.set_color(color),
2024 WritableDst::Raw(_) => Ok(())
2028 fn reset(&mut self) -> io::Result<()> {
2030 WritableDst::Terminal(ref mut t) => t.reset(),
2031 WritableDst::Buffered(_, ref mut t) => t.reset(),
2032 WritableDst::ColoredRaw(ref mut t) => t.reset(),
2033 WritableDst::Raw(_) => Ok(()),
2038 impl<'a> Write for WritableDst<'a> {
2039 fn write(&mut self, bytes: &[u8]) -> io::Result<usize> {
2041 WritableDst::Terminal(ref mut t) => t.write(bytes),
2042 WritableDst::Buffered(_, ref mut buf) => buf.write(bytes),
2043 WritableDst::Raw(ref mut w) => w.write(bytes),
2044 WritableDst::ColoredRaw(ref mut t) => t.write(bytes),
2048 fn flush(&mut self) -> io::Result<()> {
2050 WritableDst::Terminal(ref mut t) => t.flush(),
2051 WritableDst::Buffered(_, ref mut buf) => buf.flush(),
2052 WritableDst::Raw(ref mut w) => w.flush(),
2053 WritableDst::ColoredRaw(ref mut w) => w.flush(),
2058 impl<'a> Drop for WritableDst<'a> {
2059 fn drop(&mut self) {
2061 WritableDst::Buffered(ref mut dst, ref mut buf) => {
2062 drop(dst.print(buf));
2069 /// Whether the original and suggested code are visually similar enough to warrant extra wording.
2070 pub fn is_case_difference(sm: &dyn SourceMapper, suggested: &str, sp: Span) -> bool {
2071 // FIXME: this should probably be extended to also account for `FO0` → `FOO` and unicode.
2072 let found = sm.span_to_snippet(sp).unwrap();
2073 let ascii_confusables = &['c', 'f', 'i', 'k', 'o', 's', 'u', 'v', 'w', 'x', 'y', 'z'];
2074 // All the chars that differ in capitalization are confusable (above):
2075 let confusable = found.chars().zip(suggested.chars()).filter(|(f, s)| f != s).all(|(f, s)| {
2076 (ascii_confusables.contains(&f) || ascii_confusables.contains(&s))
2078 confusable && found.to_lowercase() == suggested.to_lowercase()
2079 // FIXME: We sometimes suggest the same thing we already have, which is a
2080 // bug, but be defensive against that here.
2081 && found != suggested