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::source_map::SourceMap;
13 use syntax_pos::{MultiSpan, SourceFile, Span};
15 use crate::snippet::{Annotation, AnnotationType, Line, MultilineAnnotation, Style, StyledString};
16 use crate::styled_buffer::StyledBuffer;
17 use crate::Level::Error;
19 pluralize, CodeSuggestion, Diagnostic, DiagnosticId, Level, SubDiagnostic, SuggestionStyle,
22 use rustc_data_structures::fx::FxHashMap;
23 use rustc_data_structures::sync::Lrc;
25 use std::cmp::{max, min, Reverse};
27 use std::io::prelude::*;
29 use termcolor::{Ansi, BufferWriter, ColorChoice, ColorSpec, StandardStream};
30 use termcolor::{Buffer, Color, WriteColor};
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<SourceMap>>,
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();
66 external_macro_backtrace,
71 #[derive(Clone, Copy, Debug)]
73 /// The available whitespace in the left that can be consumed when centering.
74 pub whitespace_left: usize,
75 /// The column of the beginning of left-most span.
77 /// The column of the end of right-most span.
78 pub span_right: usize,
79 /// The beginning of the line to be displayed.
80 pub computed_left: usize,
81 /// The end of the line to be displayed.
82 pub computed_right: usize,
83 /// The current width of the terminal. 140 by default and in tests.
84 pub column_width: usize,
85 /// The end column of a span label, including the span. Doesn't account for labels not in the
86 /// same line as the span.
87 pub label_right: usize,
92 whitespace_left: usize,
99 // The 6 is padding to give a bit of room for `...` when displaying:
104 // 16 | ... fn foo(self) -> Self::Bar {
109 whitespace_left: whitespace_left.saturating_sub(6),
110 span_left: span_left.saturating_sub(6),
111 span_right: span_right + 6,
115 label_right: label_right + 6,
117 m.compute(max_line_len);
121 fn was_cut_left(&self) -> bool {
122 self.computed_left > 0
125 fn was_cut_right(&self, line_len: usize) -> bool {
127 if self.computed_right == self.span_right || self.computed_right == self.label_right {
128 // Account for the "..." padding given above. Otherwise we end up with code lines that
129 // do fit but end in "..." as if they were trimmed.
130 self.computed_right - 6
134 right < line_len && self.computed_left + self.column_width < line_len
137 fn compute(&mut self, max_line_len: usize) {
138 // When there's a lot of whitespace (>20), we want to trim it as it is useless.
139 self.computed_left = if self.whitespace_left > 20 {
140 self.whitespace_left - 16 // We want some padding.
144 // We want to show as much as possible, max_line_len is the right-most boundary for the
146 self.computed_right = max(max_line_len, self.computed_left);
148 if self.computed_right - self.computed_left > self.column_width {
149 // Trimming only whitespace isn't enough, let's get craftier.
150 if self.label_right - self.whitespace_left <= self.column_width {
151 // Attempt to fit the code window only trimming whitespace.
152 self.computed_left = self.whitespace_left;
153 self.computed_right = self.computed_left + self.column_width;
154 } else if self.label_right - self.span_left <= self.column_width {
155 // Attempt to fit the code window considering only the spans and labels.
156 let padding_left = (self.column_width - (self.label_right - self.span_left)) / 2;
157 self.computed_left = self.span_left.saturating_sub(padding_left);
158 self.computed_right = self.computed_left + self.column_width;
159 } else if self.span_right - self.span_left <= self.column_width {
160 // Attempt to fit the code window considering the spans and labels plus padding.
161 let padding_left = (self.column_width - (self.span_right - self.span_left)) / 5 * 2;
162 self.computed_left = self.span_left.saturating_sub(padding_left);
163 self.computed_right = self.computed_left + self.column_width;
165 // Mostly give up but still don't show the full line.
166 self.computed_left = self.span_left;
167 self.computed_right = self.span_right;
172 fn left(&self, line_len: usize) -> usize {
173 min(self.computed_left, line_len)
176 fn right(&self, line_len: usize) -> usize {
177 if line_len.saturating_sub(self.computed_left) <= self.column_width {
180 min(line_len, self.computed_right)
185 const ANONYMIZED_LINE_NUM: &str = "LL";
187 /// Emitter trait for emitting errors.
189 /// Emit a structured diagnostic.
190 fn emit_diagnostic(&mut self, diag: &Diagnostic);
192 /// Emit a notification that an artifact has been output.
193 /// This is currently only supported for the JSON format,
194 /// other formats can, and will, simply ignore it.
195 fn emit_artifact_notification(&mut self, _path: &Path, _artifact_type: &str) {}
197 /// Checks if should show explanations about "rustc --explain"
198 fn should_show_explain(&self) -> bool {
202 fn source_map(&self) -> Option<&Lrc<SourceMap>>;
204 /// Formats the substitutions of the primary_span
206 /// The are a lot of conditions to this method, but in short:
208 /// * If the current `Diagnostic` has only one visible `CodeSuggestion`,
209 /// we format the `help` suggestion depending on the content of the
210 /// substitutions. In that case, we return the modified span only.
212 /// * If the current `Diagnostic` has multiple suggestions,
213 /// we return the original `primary_span` and the original suggestions.
214 fn primary_span_formatted<'a>(
216 diag: &'a Diagnostic,
217 ) -> (MultiSpan, &'a [CodeSuggestion]) {
218 let mut primary_span = diag.span.clone();
219 if let Some((sugg, rest)) = diag.suggestions.split_first() {
220 if rest.is_empty() &&
221 // ^ if there is only one suggestion
222 // don't display multi-suggestions as labels
223 sugg.substitutions.len() == 1 &&
224 // don't display multipart suggestions as labels
225 sugg.substitutions[0].parts.len() == 1 &&
226 // don't display long messages as labels
227 sugg.msg.split_whitespace().count() < 10 &&
228 // don't display multiline suggestions as labels
229 !sugg.substitutions[0].parts[0].snippet.contains('\n') &&
231 // when this style is set we want the suggestion to be a message, not inline
232 SuggestionStyle::HideCodeAlways,
233 // trivial suggestion for tooling's sake, never shown
234 SuggestionStyle::CompletelyHidden,
235 // subtle suggestion, never shown inline
236 SuggestionStyle::ShowAlways,
237 ].contains(&sugg.style)
239 let substitution = &sugg.substitutions[0].parts[0].snippet.trim();
240 let msg = if substitution.len() == 0 || sugg.style.hide_inline() {
241 // This substitution is only removal OR we explicitly don't want to show the
242 // code inline (`hide_inline`). Therefore, we don't show the substitution.
243 format!("help: {}", sugg.msg)
245 // Show the default suggestion text with the substitution
251 .map(|sm| is_case_difference(
254 sugg.substitutions[0].parts[0].span,
258 " (notice the capitalization)"
265 primary_span.push_span_label(sugg.substitutions[0].parts[0].span, msg);
267 // We return only the modified primary_span
270 // if there are multiple suggestions, print them all in full
271 // to be consistent. We could try to figure out if we can
272 // make one (or the first one) inline, but that would give
273 // undue importance to a semi-random suggestion
274 (primary_span, &diag.suggestions)
277 (primary_span, &diag.suggestions)
281 // This does a small "fix" for multispans by looking to see if it can find any that
282 // point directly at <*macros>. Since these are often difficult to read, this
283 // will change the span to point at the use site.
284 fn fix_multispans_in_std_macros(
286 source_map: &Option<Lrc<SourceMap>>,
287 span: &mut MultiSpan,
288 children: &mut Vec<SubDiagnostic>,
292 let mut spans_updated = self.fix_multispan_in_std_macros(source_map, span, backtrace);
293 for child in children.iter_mut() {
295 self.fix_multispan_in_std_macros(source_map, &mut child.span, backtrace);
297 let msg = if level == &Error {
298 "this error originates in a macro outside of the current crate \
299 (in Nightly builds, run with -Z external-macro-backtrace \
303 "this warning originates in a macro outside of the current crate \
304 (in Nightly builds, run with -Z external-macro-backtrace \
310 children.push(SubDiagnostic {
312 message: vec![(msg, Style::NoStyle)],
313 span: MultiSpan::new(),
319 // This "fixes" MultiSpans that contain Spans that are pointing to locations inside of
320 // <*macros>. Since these locations are often difficult to read, we move these Spans from
321 // <*macros> to their corresponding use site.
322 fn fix_multispan_in_std_macros(
324 source_map: &Option<Lrc<SourceMap>>,
325 span: &mut MultiSpan,
326 always_backtrace: bool,
328 let sm = match source_map {
330 None => return false,
333 let mut before_after: Vec<(Span, Span)> = vec![];
334 let mut new_labels: Vec<(Span, String)> = vec![];
336 // First, find all the spans in <*macros> and point instead at their use site
337 for sp in span.primary_spans() {
341 let call_sp = sm.call_span_if_macro(*sp);
342 if call_sp != *sp && !always_backtrace {
343 before_after.push((*sp, call_sp));
345 let backtrace_len = sp.macro_backtrace().len();
346 for (i, trace) in sp.macro_backtrace().iter().rev().enumerate() {
347 // Only show macro locations that are local
348 // and display them like a span_note
349 if trace.def_site_span.is_dummy() {
352 if always_backtrace {
356 "in this expansion of `{}`{}",
357 trace.macro_decl_name,
358 if backtrace_len > 2 {
359 // if backtrace_len == 1 it'll be pointed
360 // at by "in this macro invocation"
361 format!(" (#{})", i + 1)
368 // Check to make sure we're not in any <*macros>
369 if !sm.span_to_filename(trace.def_site_span).is_macros()
370 && !trace.macro_decl_name.starts_with("desugaring of ")
371 && !trace.macro_decl_name.starts_with("#[")
377 "in this macro invocation{}",
378 if backtrace_len > 2 && always_backtrace {
379 // only specify order when the macro
380 // backtrace is multiple levels deep
381 format!(" (#{})", i + 1)
387 if !always_backtrace {
393 for (label_span, label_text) in new_labels {
394 span.push_span_label(label_span, label_text);
396 for sp_label in span.span_labels() {
397 if sp_label.span.is_dummy() {
400 if sm.span_to_filename(sp_label.span.clone()).is_macros() && !always_backtrace {
401 let v = sp_label.span.macro_backtrace();
402 if let Some(use_site) = v.last() {
403 before_after.push((sp_label.span.clone(), use_site.call_site.clone()));
407 // After we have them, make sure we replace these 'bad' def sites with their use sites
408 let spans_updated = !before_after.is_empty();
409 for (before, after) in before_after {
410 span.replace(before, after);
417 impl Emitter for EmitterWriter {
418 fn source_map(&self) -> Option<&Lrc<SourceMap>> {
422 fn emit_diagnostic(&mut self, diag: &Diagnostic) {
423 let mut children = diag.children.clone();
424 let (mut primary_span, suggestions) = self.primary_span_formatted(&diag);
426 self.fix_multispans_in_std_macros(
431 self.external_macro_backtrace,
434 self.emit_messages_default(
436 &diag.styled_message(),
444 fn should_show_explain(&self) -> bool {
449 /// An emitter that does nothing when emitting a diagnostic.
450 pub struct SilentEmitter;
452 impl Emitter for SilentEmitter {
453 fn source_map(&self) -> Option<&Lrc<SourceMap>> {
456 fn emit_diagnostic(&mut self, _: &Diagnostic) {}
459 /// maximum number of lines we will print for each error; arbitrary.
460 pub const MAX_HIGHLIGHT_LINES: usize = 6;
461 /// maximum number of suggestions to be shown
463 /// Arbitrary, but taken from trait import suggestion limit
464 pub const MAX_SUGGESTIONS: usize = 4;
466 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
467 pub enum ColorConfig {
474 fn to_color_choice(self) -> ColorChoice {
476 ColorConfig::Always => {
477 if atty::is(atty::Stream::Stderr) {
480 ColorChoice::AlwaysAnsi
483 ColorConfig::Never => ColorChoice::Never,
484 ColorConfig::Auto if atty::is(atty::Stream::Stderr) => ColorChoice::Auto,
485 ColorConfig::Auto => ColorChoice::Never,
488 fn suggests_using_colors(self) -> bool {
490 ColorConfig::Always | ColorConfig::Auto => true,
491 ColorConfig::Never => false,
496 /// Handles the writing of `HumanReadableErrorType::Default` and `HumanReadableErrorType::Short`
497 pub struct EmitterWriter {
499 sm: Option<Lrc<SourceMap>>,
503 terminal_width: Option<usize>,
505 external_macro_backtrace: bool,
509 pub struct FileWithAnnotatedLines {
510 pub file: Lrc<SourceFile>,
511 pub lines: Vec<Line>,
512 multiline_depth: usize,
517 color_config: ColorConfig,
518 source_map: Option<Lrc<SourceMap>>,
521 terminal_width: Option<usize>,
522 external_macro_backtrace: bool,
524 let dst = Destination::from_stderr(color_config);
532 external_macro_backtrace,
537 dst: Box<dyn Write + Send>,
538 source_map: Option<Lrc<SourceMap>>,
542 terminal_width: Option<usize>,
543 external_macro_backtrace: bool,
546 dst: Raw(dst, colored),
552 external_macro_backtrace,
556 pub fn ui_testing(mut self, ui_testing: bool) -> Self {
557 self.ui_testing = ui_testing;
561 fn maybe_anonymized(&self, line_num: usize) -> String {
562 if self.ui_testing { ANONYMIZED_LINE_NUM.to_string() } else { line_num.to_string() }
567 buffer: &mut StyledBuffer,
575 let line_len = source_string.len();
576 // Create the source line we will highlight.
577 let left = margin.left(line_len);
578 let right = margin.right(line_len);
579 // On long lines, we strip the source line, accounting for unicode.
581 let code: String = source_string
585 // Make sure that the trimming on the right will fall within the terminal width.
586 // FIXME: `unicode_width` sometimes disagrees with terminals on how wide a `char` is.
587 // For now, just accept that sometimes the code line will be longer than desired.
588 let next = unicode_width::UnicodeWidthChar::width(*ch).unwrap_or(1);
589 if taken + next > right - left {
596 buffer.puts(line_offset, code_offset, &code, Style::Quotation);
597 if margin.was_cut_left() {
598 // We have stripped some code/whitespace from the beginning, make it clear.
599 buffer.puts(line_offset, code_offset, "...", Style::LineNumber);
601 if margin.was_cut_right(line_len) {
602 // We have stripped some code after the right-most span end, make it clear we did so.
603 buffer.puts(line_offset, code_offset + taken - 3, "...", Style::LineNumber);
605 buffer.puts(line_offset, 0, &self.maybe_anonymized(line_index), Style::LineNumber);
607 draw_col_separator(buffer, line_offset, width_offset - 2);
610 fn render_source_line(
612 buffer: &mut StyledBuffer,
613 file: Lrc<SourceFile>,
618 ) -> Vec<(usize, Style)> {
624 // | secondary span label
626 // ^^ ^ ^^^ ^^^^ ^^^ we don't care about code too far to the right of a span, we trim it
628 // | | | actual code found in your source code and the spans we use to mark it
629 // | | when there's too much wasted space to the left, trim it
630 // | vertical divider between the column number and the code
633 if line.line_index == 0 {
637 let source_string = match file.get_line(line.line_index - 1) {
639 None => return Vec::new(),
642 let line_offset = buffer.num_lines();
644 let left = margin.left(source_string.len()); // Left trim
645 // Account for unicode characters of width !=0 that were removed.
646 let left = source_string
649 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
662 // Special case when there's only one annotation involved, it is the start of a multiline
663 // span and there's no text at the beginning of the code line. Instead of doing the whole
672 // we simplify the output to:
678 if let [ann] = &line.annotations[..] {
679 if let AnnotationType::MultilineStart(depth) = ann.annotation_type {
680 if source_string.chars().take(ann.start_col).all(|c| c.is_whitespace()) {
681 let style = if ann.is_primary {
682 Style::UnderlinePrimary
684 Style::UnderlineSecondary
686 buffer.putc(line_offset, width_offset + depth - 1, '/', style);
687 return vec![(depth, style)];
692 // We want to display like this:
694 // vec.push(vec.pop().unwrap());
695 // --- ^^^ - previous borrow ends here
697 // | error occurs here
698 // previous borrow of `vec` occurs here
700 // But there are some weird edge cases to be aware of:
702 // vec.push(vec.pop().unwrap());
703 // -------- - previous borrow ends here
705 // |this makes no sense
706 // previous borrow of `vec` occurs here
708 // For this reason, we group the lines into "highlight lines"
709 // and "annotations lines", where the highlight lines have the `^`.
711 // Sort the annotations by (start, end col)
712 // The labels are reversed, sort and then reversed again.
713 // Consider a list of annotations (A1, A2, C1, C2, B1, B2) where
714 // the letter signifies the span. Here we are only sorting by the
715 // span and hence, the order of the elements with the same span will
716 // not change. On reversing the ordering (|a, b| but b.cmp(a)), you get
717 // (C1, C2, B1, B2, A1, A2). All the elements with the same span are
718 // still ordered first to last, but all the elements with different
719 // spans are ordered by their spans in last to first order. Last to
720 // first order is important, because the jiggly lines and | are on
721 // the left, so the rightmost span needs to be rendered first,
722 // otherwise the lines would end up needing to go over a message.
724 let mut annotations = line.annotations.clone();
725 annotations.sort_by_key(|a| Reverse(a.start_col));
727 // First, figure out where each label will be positioned.
729 // In the case where you have the following annotations:
731 // vec.push(vec.pop().unwrap());
732 // -------- - previous borrow ends here [C]
734 // |this makes no sense [B]
735 // previous borrow of `vec` occurs here [A]
737 // `annotations_position` will hold [(2, A), (1, B), (0, C)].
739 // We try, when possible, to stick the rightmost annotation at the end
740 // of the highlight line:
742 // vec.push(vec.pop().unwrap());
743 // --- --- - previous borrow ends here
745 // But sometimes that's not possible because one of the other
746 // annotations overlaps it. For example, from the test
747 // `span_overlap_label`, we have the following annotations
748 // (written on distinct lines for clarity):
754 // In this case, we can't stick the rightmost-most label on
755 // the highlight line, or we would get:
762 // which is totally weird. Instead we want:
770 // which is...less weird, at least. In fact, in general, if
771 // the rightmost span overlaps with any other span, we should
772 // use the "hang below" version, so we can at least make it
773 // clear where the span *starts*. There's an exception for this
774 // logic, when the labels do not have a message:
789 let mut annotations_position = vec![];
790 let mut line_len = 0;
792 for (i, annotation) in annotations.iter().enumerate() {
793 for (j, next) in annotations.iter().enumerate() {
794 if overlaps(next, annotation, 0) // This label overlaps with another one and both
795 && annotation.has_label() // take space (they have text and are not
796 && j > i // multiline lines).
798 // We're currently on the first line, move the label one line down
800 // If we're overlapping with an un-labelled annotation with the same span
801 // we can just merge them in the output
802 if next.start_col == annotation.start_col
803 && next.end_col == annotation.end_col
809 // This annotation needs a new line in the output.
814 annotations_position.push((p, annotation));
815 for (j, next) in annotations.iter().enumerate() {
817 let l = next.label.as_ref().map_or(0, |label| label.len() + 2);
818 if (overlaps(next, annotation, l) // Do not allow two labels to be in the same
819 // line if they overlap including padding, to
820 // avoid situations like:
827 && annotation.has_label() // Both labels must have some text, otherwise
828 && next.has_label()) // they are not overlapping.
829 // Do not add a new line if this annotation
830 // or the next are vertical line placeholders.
831 || (annotation.takes_space() // If either this or the next annotation is
832 && next.has_label()) // multiline start/end, move it to a new line
833 || (annotation.has_label() // so as not to overlap the orizontal lines.
834 && next.takes_space())
835 || (annotation.takes_space() && next.takes_space())
836 || (overlaps(next, annotation, l)
837 && next.end_col <= annotation.end_col
842 // This annotation needs a new line in the output.
848 line_len = max(line_len, p);
855 // If there are no annotations or the only annotations on this line are
856 // MultilineLine, then there's only code being shown, stop processing.
857 if line.annotations.iter().all(|a| a.is_line()) {
861 // Write the column separator.
863 // After this we will have:
872 for pos in 0..=line_len {
873 draw_col_separator(buffer, line_offset + pos + 1, width_offset - 2);
874 buffer.putc(line_offset + pos + 1, width_offset - 2, '|', Style::LineNumber);
877 // Write the horizontal lines for multiline annotations
878 // (only the first and last lines need this).
880 // After this we will have:
889 for &(pos, annotation) in &annotations_position {
890 let style = if annotation.is_primary {
891 Style::UnderlinePrimary
893 Style::UnderlineSecondary
896 match annotation.annotation_type {
897 AnnotationType::MultilineStart(depth) | AnnotationType::MultilineEnd(depth) => {
902 width_offset + depth,
903 code_offset + annotation.start_col - left,
908 buffer.set_style_range(
910 code_offset + annotation.start_col - left,
911 code_offset + annotation.end_col - left,
913 annotation.is_primary,
920 // Write the vertical lines for labels that are on a different line as the underline.
922 // After this we will have:
931 for &(pos, annotation) in &annotations_position {
932 let style = if annotation.is_primary {
933 Style::UnderlinePrimary
935 Style::UnderlineSecondary
939 if pos > 1 && (annotation.has_label() || annotation.takes_space()) {
940 for p in line_offset + 1..=line_offset + pos {
943 (code_offset + annotation.start_col).saturating_sub(left),
949 match annotation.annotation_type {
950 AnnotationType::MultilineStart(depth) => {
951 for p in line_offset + pos + 1..line_offset + line_len + 2 {
952 buffer.putc(p, width_offset + depth - 1, '|', style);
955 AnnotationType::MultilineEnd(depth) => {
956 for p in line_offset..=line_offset + pos {
957 buffer.putc(p, width_offset + depth - 1, '|', style);
964 // Write the labels on the annotations that actually have a label.
966 // After this we will have:
971 // | something about `foo`
975 for &(pos, annotation) in &annotations_position {
977 if annotation.is_primary { Style::LabelPrimary } else { Style::LabelSecondary };
978 let (pos, col) = if pos == 0 {
979 (pos + 1, (annotation.end_col + 1).saturating_sub(left))
981 (pos + 2, annotation.start_col.saturating_sub(left))
983 if let Some(ref label) = annotation.label {
984 buffer.puts(line_offset + pos, code_offset + col, &label, style);
988 // Sort from biggest span to smallest span so that smaller spans are
989 // represented in the output:
994 // | | something about `foo`
995 // | something about `fn foo()`
996 annotations_position.sort_by_key(|(_, ann)| {
997 // Decreasing order. When annotations share the same length, prefer `Primary`.
998 (Reverse(ann.len()), ann.is_primary)
1001 // Write the underlines.
1003 // After this we will have:
1008 // | something about `foo`
1012 for &(_, annotation) in &annotations_position {
1013 let (underline, style) = if annotation.is_primary {
1014 ('^', Style::UnderlinePrimary)
1016 ('-', Style::UnderlineSecondary)
1018 for p in annotation.start_col..annotation.end_col {
1021 (code_offset + p).saturating_sub(left),
1027 annotations_position
1029 .filter_map(|&(_, annotation)| match annotation.annotation_type {
1030 AnnotationType::MultilineStart(p) | AnnotationType::MultilineEnd(p) => {
1031 let style = if annotation.is_primary {
1034 Style::LabelSecondary
1040 .collect::<Vec<_>>()
1043 fn get_multispan_max_line_num(&mut self, msp: &MultiSpan) -> usize {
1044 let sm = match self.sm {
1050 for primary_span in msp.primary_spans() {
1051 if !primary_span.is_dummy() {
1052 let hi = sm.lookup_char_pos(primary_span.hi());
1053 max = (hi.line).max(max);
1056 if !self.short_message {
1057 for span_label in msp.span_labels() {
1058 if !span_label.span.is_dummy() {
1059 let hi = sm.lookup_char_pos(span_label.span.hi());
1060 max = (hi.line).max(max);
1068 fn get_max_line_num(&mut self, span: &MultiSpan, children: &[SubDiagnostic]) -> usize {
1069 let primary = self.get_multispan_max_line_num(span);
1072 .map(|sub| self.get_multispan_max_line_num(&sub.span))
1078 /// Adds a left margin to every line but the first, given a padding length and the label being
1079 /// displayed, keeping the provided highlighting.
1082 buffer: &mut StyledBuffer,
1083 msg: &[(String, Style)],
1086 override_style: Option<Style>,
1088 // The extra 5 ` ` is padding that's always needed to align to the `note: `:
1091 // --> file.rs:13:20
1096 // = note: multiline
1101 // | | length of label
1103 // `max_line_num_len`
1104 let padding = " ".repeat(padding + label.len() + 5);
1106 /// Returns `override` if it is present and `style` is `NoStyle` or `style` otherwise
1107 fn style_or_override(style: Style, override_: Option<Style>) -> Style {
1108 match (style, override_) {
1109 (Style::NoStyle, Some(override_)) => override_,
1114 let mut line_number = 0;
1116 // Provided the following diagnostic message:
1120 // ("highlighted multiline\nstring to\nsee how it ", Style::NoStyle),
1121 // ("looks", Style::Highlight),
1122 // ("with\nvery ", Style::NoStyle),
1123 // ("weird", Style::Highlight),
1124 // (" formats\n", Style::NoStyle),
1125 // ("see?", Style::Highlight),
1128 // the expected output on a note is (* surround the highlighted text)
1130 // = note: highlighted multiline
1132 // see how it *looks* with
1133 // very *weird* formats
1135 for &(ref text, ref style) in msg.iter() {
1136 let lines = text.split('\n').collect::<Vec<_>>();
1137 if lines.len() > 1 {
1138 for (i, line) in lines.iter().enumerate() {
1141 buffer.append(line_number, &padding, Style::NoStyle);
1143 buffer.append(line_number, line, style_or_override(*style, override_style));
1146 buffer.append(line_number, text, style_or_override(*style, override_style));
1151 fn emit_message_default(
1154 msg: &[(String, Style)],
1155 code: &Option<DiagnosticId>,
1157 max_line_num_len: usize,
1159 ) -> io::Result<()> {
1160 let mut buffer = StyledBuffer::new();
1161 let header_style = if is_secondary { Style::HeaderMsg } else { Style::MainHeaderMsg };
1163 if !msp.has_primary_spans() && !msp.has_span_labels() && is_secondary && !self.short_message
1165 // This is a secondary message with no span info
1166 for _ in 0..max_line_num_len {
1167 buffer.prepend(0, " ", Style::NoStyle);
1169 draw_note_separator(&mut buffer, 0, max_line_num_len + 1);
1170 if *level != Level::FailureNote {
1171 let level_str = level.to_string();
1172 if !level_str.is_empty() {
1173 buffer.append(0, &level_str, Style::MainHeaderMsg);
1174 buffer.append(0, ": ", Style::NoStyle);
1177 self.msg_to_buffer(&mut buffer, msg, max_line_num_len, "note", None);
1179 let level_str = level.to_string();
1180 // The failure note level itself does not provide any useful diagnostic information
1181 if *level != Level::FailureNote && !level_str.is_empty() {
1182 buffer.append(0, &level_str, Style::Level(level.clone()));
1184 // only render error codes, not lint codes
1185 if let Some(DiagnosticId::Error(ref code)) = *code {
1186 buffer.append(0, "[", Style::Level(level.clone()));
1187 buffer.append(0, &code, Style::Level(level.clone()));
1188 buffer.append(0, "]", Style::Level(level.clone()));
1190 if *level != Level::FailureNote && !level_str.is_empty() {
1191 buffer.append(0, ": ", header_style);
1193 for &(ref text, _) in msg.iter() {
1194 buffer.append(0, text, header_style);
1198 let mut annotated_files = FileWithAnnotatedLines::collect_annotations(msp, &self.sm);
1200 // Make sure our primary file comes first
1201 let (primary_lo, sm) = if let (Some(sm), Some(ref primary_span)) =
1202 (self.sm.as_ref(), msp.primary_span().as_ref())
1204 if !primary_span.is_dummy() {
1205 (sm.lookup_char_pos(primary_span.lo()), sm)
1207 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1211 // If we don't have span information, emit and exit
1212 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1216 annotated_files.binary_search_by(|x| x.file.name.cmp(&primary_lo.file.name))
1218 annotated_files.swap(0, pos);
1221 // Print out the annotate source lines that correspond with the error
1222 for annotated_file in annotated_files {
1223 // we can't annotate anything if the source is unavailable.
1224 if !sm.ensure_source_file_source_present(annotated_file.file.clone()) {
1228 // print out the span location and spacer before we print the annotated source
1229 // to do this, we need to know if this span will be primary
1230 let is_primary = primary_lo.file.name == annotated_file.file.name;
1232 let loc = primary_lo.clone();
1233 if !self.short_message {
1234 // remember where we are in the output buffer for easy reference
1235 let buffer_msg_line_offset = buffer.num_lines();
1237 buffer.prepend(buffer_msg_line_offset, "--> ", Style::LineNumber);
1239 buffer_msg_line_offset,
1243 sm.doctest_offset_line(&loc.file.name, loc.line),
1246 Style::LineAndColumn,
1248 for _ in 0..max_line_num_len {
1249 buffer.prepend(buffer_msg_line_offset, " ", Style::NoStyle);
1257 sm.doctest_offset_line(&loc.file.name, loc.line),
1260 Style::LineAndColumn,
1263 } else if !self.short_message {
1264 // remember where we are in the output buffer for easy reference
1265 let buffer_msg_line_offset = buffer.num_lines();
1268 draw_col_separator(&mut buffer, buffer_msg_line_offset, max_line_num_len + 1);
1270 // Then, the secondary file indicator
1271 buffer.prepend(buffer_msg_line_offset + 1, "::: ", Style::LineNumber);
1272 let loc = if let Some(first_line) = annotated_file.lines.first() {
1273 let col = if let Some(first_annotation) = first_line.annotations.first() {
1274 format!(":{}", first_annotation.start_col + 1)
1280 annotated_file.file.name,
1281 sm.doctest_offset_line(&annotated_file.file.name, first_line.line_index),
1285 annotated_file.file.name.to_string()
1287 buffer.append(buffer_msg_line_offset + 1, &loc, Style::LineAndColumn);
1288 for _ in 0..max_line_num_len {
1289 buffer.prepend(buffer_msg_line_offset + 1, " ", Style::NoStyle);
1293 if !self.short_message {
1294 // Put in the spacer between the location and annotated source
1295 let buffer_msg_line_offset = buffer.num_lines();
1296 draw_col_separator_no_space(
1298 buffer_msg_line_offset,
1299 max_line_num_len + 1,
1302 // Contains the vertical lines' positions for active multiline annotations
1303 let mut multilines = FxHashMap::default();
1305 // Get the left-side margin to remove it
1306 let mut whitespace_margin = std::usize::MAX;
1307 for line_idx in 0..annotated_file.lines.len() {
1308 let file = annotated_file.file.clone();
1309 let line = &annotated_file.lines[line_idx];
1310 if let Some(source_string) = file.get_line(line.line_index - 1) {
1311 let leading_whitespace =
1312 source_string.chars().take_while(|c| c.is_whitespace()).count();
1313 if source_string.chars().any(|c| !c.is_whitespace()) {
1314 whitespace_margin = min(whitespace_margin, leading_whitespace);
1318 if whitespace_margin == std::usize::MAX {
1319 whitespace_margin = 0;
1322 // Left-most column any visible span points at.
1323 let mut span_left_margin = std::usize::MAX;
1324 for line in &annotated_file.lines {
1325 for ann in &line.annotations {
1326 span_left_margin = min(span_left_margin, ann.start_col);
1327 span_left_margin = min(span_left_margin, ann.end_col);
1330 if span_left_margin == std::usize::MAX {
1331 span_left_margin = 0;
1334 // Right-most column any visible span points at.
1335 let mut span_right_margin = 0;
1336 let mut label_right_margin = 0;
1337 let mut max_line_len = 0;
1338 for line in &annotated_file.lines {
1341 annotated_file.file.get_line(line.line_index - 1).map_or(0, |s| s.len()),
1343 for ann in &line.annotations {
1344 span_right_margin = max(span_right_margin, ann.start_col);
1345 span_right_margin = max(span_right_margin, ann.end_col);
1346 // FIXME: account for labels not in the same line
1347 let label_right = ann.label.as_ref().map_or(0, |l| l.len() + 1);
1348 label_right_margin = max(label_right_margin, ann.end_col + label_right);
1352 let width_offset = 3 + max_line_num_len;
1353 let code_offset = if annotated_file.multiline_depth == 0 {
1356 width_offset + annotated_file.multiline_depth + 1
1359 let column_width = if let Some(width) = self.terminal_width {
1360 width.saturating_sub(code_offset)
1361 } else if self.ui_testing {
1364 term_size::dimensions()
1365 .map(|(w, _)| w.saturating_sub(code_offset))
1366 .unwrap_or(std::usize::MAX)
1369 let margin = Margin::new(
1378 // Next, output the annotate source for this file
1379 for line_idx in 0..annotated_file.lines.len() {
1380 let previous_buffer_line = buffer.num_lines();
1382 let depths = self.render_source_line(
1384 annotated_file.file.clone(),
1385 &annotated_file.lines[line_idx],
1391 let mut to_add = FxHashMap::default();
1393 for (depth, style) in depths {
1394 if multilines.get(&depth).is_some() {
1395 multilines.remove(&depth);
1397 to_add.insert(depth, style);
1401 // Set the multiline annotation vertical lines to the left of
1402 // the code in this line.
1403 for (depth, style) in &multilines {
1404 for line in previous_buffer_line..buffer.num_lines() {
1405 draw_multiline_line(&mut buffer, line, width_offset, *depth, *style);
1408 // check to see if we need to print out or elide lines that come between
1409 // this annotated line and the next one.
1410 if line_idx < (annotated_file.lines.len() - 1) {
1411 let line_idx_delta = annotated_file.lines[line_idx + 1].line_index
1412 - annotated_file.lines[line_idx].line_index;
1413 if line_idx_delta > 2 {
1414 let last_buffer_line_num = buffer.num_lines();
1415 buffer.puts(last_buffer_line_num, 0, "...", Style::LineNumber);
1417 // Set the multiline annotation vertical lines on `...` bridging line.
1418 for (depth, style) in &multilines {
1419 draw_multiline_line(
1421 last_buffer_line_num,
1427 } else if line_idx_delta == 2 {
1428 let unannotated_line = annotated_file
1430 .get_line(annotated_file.lines[line_idx].line_index)
1431 .unwrap_or_else(|| Cow::from(""));
1433 let last_buffer_line_num = buffer.num_lines();
1438 annotated_file.lines[line_idx + 1].line_index - 1,
1439 last_buffer_line_num,
1445 for (depth, style) in &multilines {
1446 draw_multiline_line(
1448 last_buffer_line_num,
1457 multilines.extend(&to_add);
1462 // final step: take our styled buffer, render it, then output it
1463 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1468 fn emit_suggestion_default(
1470 suggestion: &CodeSuggestion,
1472 max_line_num_len: usize,
1473 ) -> io::Result<()> {
1474 let sm = match self.sm {
1476 None => return Ok(()),
1479 let mut buffer = StyledBuffer::new();
1481 // Render the suggestion message
1482 let level_str = level.to_string();
1483 if !level_str.is_empty() {
1484 buffer.append(0, &level_str, Style::Level(level.clone()));
1485 buffer.append(0, ": ", Style::HeaderMsg);
1489 &[(suggestion.msg.to_owned(), Style::NoStyle)],
1492 Some(Style::HeaderMsg),
1495 // Render the replacements for each suggestion
1496 let suggestions = suggestion.splice_lines(&**sm);
1498 let mut row_num = 2;
1499 let mut notice_capitalization = false;
1500 for (complete, parts, only_capitalization) in suggestions.iter().take(MAX_SUGGESTIONS) {
1501 notice_capitalization |= only_capitalization;
1502 // Only show underline if the suggestion spans a single line and doesn't cover the
1503 // entirety of the code output. If you have multiple replacements in the same line
1504 // of code, show the underline.
1505 let show_underline = !(parts.len() == 1 && parts[0].snippet.trim() == complete.trim())
1506 && complete.lines().count() == 1;
1508 let lines = sm.span_to_lines(parts[0].span).unwrap();
1510 assert!(!lines.lines.is_empty());
1512 let line_start = sm.lookup_char_pos(parts[0].span.lo()).line;
1513 draw_col_separator_no_space(&mut buffer, 1, max_line_num_len + 1);
1514 let mut line_pos = 0;
1515 let mut lines = complete.lines();
1516 for line in lines.by_ref().take(MAX_HIGHLIGHT_LINES) {
1517 // Print the span column to avoid confusion
1521 &self.maybe_anonymized(line_start + line_pos),
1524 // print the suggestion
1525 draw_col_separator(&mut buffer, row_num, max_line_num_len + 1);
1526 buffer.append(row_num, line, Style::NoStyle);
1531 // This offset and the ones below need to be signed to account for replacement code
1532 // that is shorter than the original code.
1533 let mut offset: isize = 0;
1534 // Only show an underline in the suggestions if the suggestion is not the
1535 // entirety of the code being shown and the displayed code is not multiline.
1537 draw_col_separator(&mut buffer, row_num, max_line_num_len + 1);
1539 let span_start_pos = sm.lookup_char_pos(part.span.lo()).col_display;
1540 let span_end_pos = sm.lookup_char_pos(part.span.hi()).col_display;
1542 // Do not underline the leading...
1543 let start = part.snippet.len().saturating_sub(part.snippet.trim_start().len());
1544 // ...or trailing spaces. Account for substitutions containing unicode
1546 let sub_len: usize = part
1550 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
1553 let underline_start = (span_start_pos + start) as isize + offset;
1554 let underline_end = (span_start_pos + start + sub_len) as isize + offset;
1555 for p in underline_start..underline_end {
1558 max_line_num_len + 3 + p as usize,
1560 Style::UnderlinePrimary,
1563 // underline removals too
1564 if underline_start == underline_end {
1565 for p in underline_start - 1..underline_start + 1 {
1568 max_line_num_len + 3 + p as usize,
1570 Style::UnderlineSecondary,
1575 // length of the code after substitution
1576 let full_sub_len = part
1579 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
1580 .sum::<usize>() as isize;
1582 // length of the code to be substituted
1583 let snippet_len = span_end_pos as isize - span_start_pos as isize;
1584 // For multiple substitutions, use the position *after* the previous
1585 // substitutions have happened.
1586 offset += full_sub_len - snippet_len;
1591 // if we elided some lines, add an ellipsis
1592 if lines.next().is_some() {
1593 buffer.puts(row_num, max_line_num_len - 1, "...", Style::LineNumber);
1594 } else if !show_underline {
1595 draw_col_separator_no_space(&mut buffer, row_num, max_line_num_len + 1);
1599 if suggestions.len() > MAX_SUGGESTIONS {
1600 let others = suggestions.len() - MAX_SUGGESTIONS;
1601 let msg = format!("and {} other candidate{}", others, pluralize!(others));
1602 buffer.puts(row_num, max_line_num_len + 3, &msg, Style::NoStyle);
1603 } else if notice_capitalization {
1604 let msg = "notice the capitalization difference";
1605 buffer.puts(row_num, max_line_num_len + 3, &msg, Style::NoStyle);
1607 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1611 fn emit_messages_default(
1614 message: &[(String, Style)],
1615 code: &Option<DiagnosticId>,
1617 children: &[SubDiagnostic],
1618 suggestions: &[CodeSuggestion],
1620 let max_line_num_len = if self.ui_testing {
1621 ANONYMIZED_LINE_NUM.len()
1623 self.get_max_line_num(span, children).to_string().len()
1626 match self.emit_message_default(span, message, code, level, max_line_num_len, false) {
1628 if !children.is_empty()
1629 || suggestions.iter().any(|s| s.style != SuggestionStyle::CompletelyHidden)
1631 let mut buffer = StyledBuffer::new();
1632 if !self.short_message {
1633 draw_col_separator_no_space(&mut buffer, 0, max_line_num_len + 1);
1635 match emit_to_destination(
1642 Err(e) => panic!("failed to emit error: {}", e),
1645 if !self.short_message {
1646 for child in children {
1647 let span = child.render_span.as_ref().unwrap_or(&child.span);
1648 match self.emit_message_default(
1650 &child.styled_message(),
1656 Err(e) => panic!("failed to emit error: {}", e),
1660 for sugg in suggestions {
1661 if sugg.style == SuggestionStyle::CompletelyHidden {
1662 // do not display this suggestion, it is meant only for tools
1663 } else if sugg.style == SuggestionStyle::HideCodeAlways {
1664 match self.emit_message_default(
1666 &[(sugg.msg.to_owned(), Style::HeaderMsg)],
1672 Err(e) => panic!("failed to emit error: {}", e),
1676 match self.emit_suggestion_default(sugg, &Level::Help, max_line_num_len)
1678 Err(e) => panic!("failed to emit error: {}", e),
1685 Err(e) => panic!("failed to emit error: {}", e),
1688 let mut dst = self.dst.writable();
1689 match writeln!(dst) {
1690 Err(e) => panic!("failed to emit error: {}", e),
1691 _ => match dst.flush() {
1692 Err(e) => panic!("failed to emit error: {}", e),
1699 impl FileWithAnnotatedLines {
1700 /// Preprocess all the annotations so that they are grouped by file and by line number
1701 /// This helps us quickly iterate over the whole message (including secondary file spans)
1702 pub fn collect_annotations(
1704 source_map: &Option<Lrc<SourceMap>>,
1705 ) -> Vec<FileWithAnnotatedLines> {
1706 fn add_annotation_to_file(
1707 file_vec: &mut Vec<FileWithAnnotatedLines>,
1708 file: Lrc<SourceFile>,
1712 for slot in file_vec.iter_mut() {
1713 // Look through each of our files for the one we're adding to
1714 if slot.file.name == file.name {
1715 // See if we already have a line for it
1716 for line_slot in &mut slot.lines {
1717 if line_slot.line_index == line_index {
1718 line_slot.annotations.push(ann);
1722 // We don't have a line yet, create one
1723 slot.lines.push(Line { line_index, annotations: vec![ann] });
1728 // This is the first time we're seeing the file
1729 file_vec.push(FileWithAnnotatedLines {
1731 lines: vec![Line { line_index, annotations: vec![ann] }],
1736 let mut output = vec![];
1737 let mut multiline_annotations = vec![];
1739 if let Some(ref sm) = source_map {
1740 for span_label in msp.span_labels() {
1741 if span_label.span.is_dummy() {
1745 let lo = sm.lookup_char_pos(span_label.span.lo());
1746 let mut hi = sm.lookup_char_pos(span_label.span.hi());
1748 // Watch out for "empty spans". If we get a span like 6..6, we
1749 // want to just display a `^` at 6, so convert that to
1750 // 6..7. This is degenerate input, but it's best to degrade
1751 // gracefully -- and the parser likes to supply a span like
1752 // that for EOF, in particular.
1754 if lo.col_display == hi.col_display && lo.line == hi.line {
1755 hi.col_display += 1;
1758 if lo.line != hi.line {
1759 let ml = MultilineAnnotation {
1761 line_start: lo.line,
1763 start_col: lo.col_display,
1764 end_col: hi.col_display,
1765 is_primary: span_label.is_primary,
1766 label: span_label.label,
1767 overlaps_exactly: false,
1769 multiline_annotations.push((lo.file, ml));
1771 let ann = Annotation {
1772 start_col: lo.col_display,
1773 end_col: hi.col_display,
1774 is_primary: span_label.is_primary,
1775 label: span_label.label,
1776 annotation_type: AnnotationType::Singleline,
1778 add_annotation_to_file(&mut output, lo.file, lo.line, ann);
1783 // Find overlapping multiline annotations, put them at different depths
1784 multiline_annotations.sort_by_key(|&(_, ref ml)| (ml.line_start, ml.line_end));
1785 for (_, ann) in multiline_annotations.clone() {
1786 for (_, a) in multiline_annotations.iter_mut() {
1787 // Move all other multiline annotations overlapping with this one
1788 // one level to the right.
1789 if !(ann.same_span(a))
1790 && num_overlap(ann.line_start, ann.line_end, a.line_start, a.line_end, true)
1793 } else if ann.same_span(a) && &ann != a {
1794 a.overlaps_exactly = true;
1801 let mut max_depth = 0; // max overlapping multiline spans
1802 for (file, ann) in multiline_annotations {
1803 max_depth = max(max_depth, ann.depth);
1804 let mut end_ann = ann.as_end();
1805 if !ann.overlaps_exactly {
1806 // avoid output like
1828 add_annotation_to_file(&mut output, file.clone(), ann.line_start, ann.as_start());
1829 // 4 is the minimum vertical length of a multiline span when presented: two lines
1830 // of code and two lines of underline. This is not true for the special case where
1831 // the beginning doesn't have an underline, but the current logic seems to be
1832 // working correctly.
1833 let middle = min(ann.line_start + 4, ann.line_end);
1834 for line in ann.line_start + 1..middle {
1835 // Every `|` that joins the beginning of the span (`___^`) to the end (`|__^`).
1836 add_annotation_to_file(&mut output, file.clone(), line, ann.as_line());
1838 let line_end = ann.line_end - 1;
1839 if middle < line_end {
1840 add_annotation_to_file(&mut output, file.clone(), line_end, ann.as_line());
1843 end_ann.annotation_type = AnnotationType::Singleline;
1845 add_annotation_to_file(&mut output, file, ann.line_end, end_ann);
1847 for file_vec in output.iter_mut() {
1848 file_vec.multiline_depth = max_depth;
1854 fn draw_col_separator(buffer: &mut StyledBuffer, line: usize, col: usize) {
1855 buffer.puts(line, col, "| ", Style::LineNumber);
1858 fn draw_col_separator_no_space(buffer: &mut StyledBuffer, line: usize, col: usize) {
1859 draw_col_separator_no_space_with_style(buffer, line, col, Style::LineNumber);
1862 fn draw_col_separator_no_space_with_style(
1863 buffer: &mut StyledBuffer,
1868 buffer.putc(line, col, '|', style);
1872 buffer: &mut StyledBuffer,
1879 for col in col_from..col_to {
1880 buffer.putc(line, col, symbol, style);
1884 fn draw_note_separator(buffer: &mut StyledBuffer, line: usize, col: usize) {
1885 buffer.puts(line, col, "= ", Style::LineNumber);
1888 fn draw_multiline_line(
1889 buffer: &mut StyledBuffer,
1895 buffer.putc(line, offset + depth - 1, '|', style);
1905 let extra = if inclusive { 1 } else { 0 };
1906 (b_start..b_end + extra).contains(&a_start) || (a_start..a_end + extra).contains(&b_start)
1908 fn overlaps(a1: &Annotation, a2: &Annotation, padding: usize) -> bool {
1909 num_overlap(a1.start_col, a1.end_col + padding, a2.start_col, a2.end_col, false)
1912 fn emit_to_destination(
1913 rendered_buffer: &[Vec<StyledString>],
1915 dst: &mut Destination,
1916 short_message: bool,
1917 ) -> io::Result<()> {
1920 let mut dst = dst.writable();
1922 // In order to prevent error message interleaving, where multiple error lines get intermixed
1923 // when multiple compiler processes error simultaneously, we emit errors with additional
1926 // On Unix systems, we write into a buffered terminal rather than directly to a terminal. When
1927 // the .flush() is called we take the buffer created from the buffered writes and write it at
1928 // one shot. Because the Unix systems use ANSI for the colors, which is a text-based styling
1929 // scheme, this buffered approach works and maintains the styling.
1931 // On Windows, styling happens through calls to a terminal API. This prevents us from using the
1932 // same buffering approach. Instead, we use a global Windows mutex, which we acquire long
1933 // enough to output the full error message, then we release.
1934 let _buffer_lock = lock::acquire_global_lock("rustc_errors");
1935 for (pos, line) in rendered_buffer.iter().enumerate() {
1937 dst.apply_style(lvl.clone(), part.style)?;
1938 write!(dst, "{}", part.text)?;
1941 if !short_message && (!lvl.is_failure_note() || pos != rendered_buffer.len() - 1) {
1949 pub enum Destination {
1950 Terminal(StandardStream),
1951 Buffered(BufferWriter),
1952 // The bool denotes whether we should be emitting ansi color codes or not
1953 Raw(Box<(dyn Write + Send)>, bool),
1956 pub enum WritableDst<'a> {
1957 Terminal(&'a mut StandardStream),
1958 Buffered(&'a mut BufferWriter, Buffer),
1959 Raw(&'a mut (dyn Write + Send)),
1960 ColoredRaw(Ansi<&'a mut (dyn Write + Send)>),
1964 fn from_stderr(color: ColorConfig) -> Destination {
1965 let choice = color.to_color_choice();
1966 // On Windows we'll be performing global synchronization on the entire
1967 // system for emitting rustc errors, so there's no need to buffer
1970 // On non-Windows we rely on the atomicity of `write` to ensure errors
1971 // don't get all jumbled up.
1973 Terminal(StandardStream::stderr(choice))
1975 Buffered(BufferWriter::stderr(choice))
1979 fn writable(&mut self) -> WritableDst<'_> {
1981 Destination::Terminal(ref mut t) => WritableDst::Terminal(t),
1982 Destination::Buffered(ref mut t) => {
1983 let buf = t.buffer();
1984 WritableDst::Buffered(t, buf)
1986 Destination::Raw(ref mut t, false) => WritableDst::Raw(t),
1987 Destination::Raw(ref mut t, true) => WritableDst::ColoredRaw(Ansi::new(t)),
1992 impl<'a> WritableDst<'a> {
1993 fn apply_style(&mut self, lvl: Level, style: Style) -> io::Result<()> {
1994 let mut spec = ColorSpec::new();
1996 Style::LineAndColumn => {}
1997 Style::LineNumber => {
1998 spec.set_bold(true);
1999 spec.set_intense(true);
2001 spec.set_fg(Some(Color::Cyan));
2003 spec.set_fg(Some(Color::Blue));
2006 Style::Quotation => {}
2007 Style::MainHeaderMsg => {
2008 spec.set_bold(true);
2010 spec.set_intense(true).set_fg(Some(Color::White));
2013 Style::UnderlinePrimary | Style::LabelPrimary => {
2015 spec.set_bold(true);
2017 Style::UnderlineSecondary | Style::LabelSecondary => {
2018 spec.set_bold(true).set_intense(true);
2020 spec.set_fg(Some(Color::Cyan));
2022 spec.set_fg(Some(Color::Blue));
2025 Style::HeaderMsg | Style::NoStyle => {}
2026 Style::Level(lvl) => {
2028 spec.set_bold(true);
2030 Style::Highlight => {
2031 spec.set_bold(true);
2034 self.set_color(&spec)
2037 fn set_color(&mut self, color: &ColorSpec) -> io::Result<()> {
2039 WritableDst::Terminal(ref mut t) => t.set_color(color),
2040 WritableDst::Buffered(_, ref mut t) => t.set_color(color),
2041 WritableDst::ColoredRaw(ref mut t) => t.set_color(color),
2042 WritableDst::Raw(_) => Ok(()),
2046 fn reset(&mut self) -> io::Result<()> {
2048 WritableDst::Terminal(ref mut t) => t.reset(),
2049 WritableDst::Buffered(_, ref mut t) => t.reset(),
2050 WritableDst::ColoredRaw(ref mut t) => t.reset(),
2051 WritableDst::Raw(_) => Ok(()),
2056 impl<'a> Write for WritableDst<'a> {
2057 fn write(&mut self, bytes: &[u8]) -> io::Result<usize> {
2059 WritableDst::Terminal(ref mut t) => t.write(bytes),
2060 WritableDst::Buffered(_, ref mut buf) => buf.write(bytes),
2061 WritableDst::Raw(ref mut w) => w.write(bytes),
2062 WritableDst::ColoredRaw(ref mut t) => t.write(bytes),
2066 fn flush(&mut self) -> io::Result<()> {
2068 WritableDst::Terminal(ref mut t) => t.flush(),
2069 WritableDst::Buffered(_, ref mut buf) => buf.flush(),
2070 WritableDst::Raw(ref mut w) => w.flush(),
2071 WritableDst::ColoredRaw(ref mut w) => w.flush(),
2076 impl<'a> Drop for WritableDst<'a> {
2077 fn drop(&mut self) {
2079 WritableDst::Buffered(ref mut dst, ref mut buf) => {
2080 drop(dst.print(buf));
2087 /// Whether the original and suggested code are visually similar enough to warrant extra wording.
2088 pub fn is_case_difference(sm: &SourceMap, suggested: &str, sp: Span) -> bool {
2089 // FIXME: this should probably be extended to also account for `FO0` → `FOO` and unicode.
2090 let found = sm.span_to_snippet(sp).unwrap();
2091 let ascii_confusables = &['c', 'f', 'i', 'k', 'o', 's', 'u', 'v', 'w', 'x', 'y', 'z'];
2092 // All the chars that differ in capitalization are confusable (above):
2093 let confusable = found
2095 .zip(suggested.chars())
2096 .filter(|(f, s)| f != s)
2097 .all(|(f, s)| (ascii_confusables.contains(&f) || ascii_confusables.contains(&s)));
2098 confusable && found.to_lowercase() == suggested.to_lowercase()
2099 // FIXME: We sometimes suggest the same thing we already have, which is a
2100 // bug, but be defensive against that here.
2101 && found != suggested