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 rustc_span::source_map::SourceMap;
13 use rustc_span::{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,
23 use rustc_data_structures::fx::FxHashMap;
24 use rustc_data_structures::sync::Lrc;
25 use rustc_span::hygiene::{ExpnKind, MacroKind};
27 use std::cmp::{max, min, Reverse};
29 use std::io::prelude::*;
31 use termcolor::{Ansi, BufferWriter, ColorChoice, ColorSpec, StandardStream};
32 use termcolor::{Buffer, Color, WriteColor};
34 /// Describes the way the content of the `rendered` field of the json output is generated
35 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
36 pub enum HumanReadableErrorType {
38 AnnotateSnippet(ColorConfig),
42 impl HumanReadableErrorType {
43 /// Returns a (`short`, `color`) tuple
44 pub fn unzip(self) -> (bool, ColorConfig) {
46 HumanReadableErrorType::Default(cc) => (false, cc),
47 HumanReadableErrorType::Short(cc) => (true, cc),
48 HumanReadableErrorType::AnnotateSnippet(cc) => (false, cc),
53 dst: Box<dyn Write + Send>,
54 source_map: Option<Lrc<SourceMap>>,
56 terminal_width: Option<usize>,
57 external_macro_backtrace: bool,
59 let (short, color_config) = self.unzip();
60 let color = color_config.suggests_using_colors();
68 external_macro_backtrace,
73 #[derive(Clone, Copy, Debug)]
75 /// The available whitespace in the left that can be consumed when centering.
76 pub whitespace_left: usize,
77 /// The column of the beginning of left-most span.
79 /// The column of the end of right-most span.
80 pub span_right: usize,
81 /// The beginning of the line to be displayed.
82 pub computed_left: usize,
83 /// The end of the line to be displayed.
84 pub computed_right: usize,
85 /// The current width of the terminal. 140 by default and in tests.
86 pub column_width: usize,
87 /// The end column of a span label, including the span. Doesn't account for labels not in the
88 /// same line as the span.
89 pub label_right: usize,
94 whitespace_left: usize,
101 // The 6 is padding to give a bit of room for `...` when displaying:
106 // 16 | ... fn foo(self) -> Self::Bar {
111 whitespace_left: whitespace_left.saturating_sub(6),
112 span_left: span_left.saturating_sub(6),
113 span_right: span_right + 6,
117 label_right: label_right + 6,
119 m.compute(max_line_len);
123 fn was_cut_left(&self) -> bool {
124 self.computed_left > 0
127 fn was_cut_right(&self, line_len: usize) -> bool {
129 if self.computed_right == self.span_right || self.computed_right == self.label_right {
130 // Account for the "..." padding given above. Otherwise we end up with code lines that
131 // do fit but end in "..." as if they were trimmed.
132 self.computed_right - 6
136 right < line_len && self.computed_left + self.column_width < line_len
139 fn compute(&mut self, max_line_len: usize) {
140 // When there's a lot of whitespace (>20), we want to trim it as it is useless.
141 self.computed_left = if self.whitespace_left > 20 {
142 self.whitespace_left - 16 // We want some padding.
146 // We want to show as much as possible, max_line_len is the right-most boundary for the
148 self.computed_right = max(max_line_len, self.computed_left);
150 if self.computed_right - self.computed_left > self.column_width {
151 // Trimming only whitespace isn't enough, let's get craftier.
152 if self.label_right - self.whitespace_left <= self.column_width {
153 // Attempt to fit the code window only trimming whitespace.
154 self.computed_left = self.whitespace_left;
155 self.computed_right = self.computed_left + self.column_width;
156 } else if self.label_right - self.span_left <= self.column_width {
157 // Attempt to fit the code window considering only the spans and labels.
158 let padding_left = (self.column_width - (self.label_right - self.span_left)) / 2;
159 self.computed_left = self.span_left.saturating_sub(padding_left);
160 self.computed_right = self.computed_left + self.column_width;
161 } else if self.span_right - self.span_left <= self.column_width {
162 // Attempt to fit the code window considering the spans and labels plus padding.
163 let padding_left = (self.column_width - (self.span_right - self.span_left)) / 5 * 2;
164 self.computed_left = self.span_left.saturating_sub(padding_left);
165 self.computed_right = self.computed_left + self.column_width;
167 // Mostly give up but still don't show the full line.
168 self.computed_left = self.span_left;
169 self.computed_right = self.span_right;
174 fn left(&self, line_len: usize) -> usize {
175 min(self.computed_left, line_len)
178 fn right(&self, line_len: usize) -> usize {
179 if line_len.saturating_sub(self.computed_left) <= self.column_width {
182 min(line_len, self.computed_right)
187 const ANONYMIZED_LINE_NUM: &str = "LL";
189 /// Emitter trait for emitting errors.
191 /// Emit a structured diagnostic.
192 fn emit_diagnostic(&mut self, diag: &Diagnostic);
194 /// Emit a notification that an artifact has been output.
195 /// This is currently only supported for the JSON format,
196 /// other formats can, and will, simply ignore it.
197 fn emit_artifact_notification(&mut self, _path: &Path, _artifact_type: &str) {}
199 /// Checks if should show explanations about "rustc --explain"
200 fn should_show_explain(&self) -> bool {
204 fn source_map(&self) -> Option<&Lrc<SourceMap>>;
206 /// Formats the substitutions of the primary_span
208 /// The are a lot of conditions to this method, but in short:
210 /// * If the current `Diagnostic` has only one visible `CodeSuggestion`,
211 /// we format the `help` suggestion depending on the content of the
212 /// substitutions. In that case, we return the modified span only.
214 /// * If the current `Diagnostic` has multiple suggestions,
215 /// we return the original `primary_span` and the original suggestions.
216 fn primary_span_formatted<'a>(
218 diag: &'a Diagnostic,
219 ) -> (MultiSpan, &'a [CodeSuggestion]) {
220 let mut primary_span = diag.span.clone();
221 if let Some((sugg, rest)) = diag.suggestions.split_first() {
222 if rest.is_empty() &&
223 // ^ if there is only one suggestion
224 // don't display multi-suggestions as labels
225 sugg.substitutions.len() == 1 &&
226 // don't display multipart suggestions as labels
227 sugg.substitutions[0].parts.len() == 1 &&
228 // don't display long messages as labels
229 sugg.msg.split_whitespace().count() < 10 &&
230 // don't display multiline suggestions as labels
231 !sugg.substitutions[0].parts[0].snippet.contains('\n') &&
233 // when this style is set we want the suggestion to be a message, not inline
234 SuggestionStyle::HideCodeAlways,
235 // trivial suggestion for tooling's sake, never shown
236 SuggestionStyle::CompletelyHidden,
237 // subtle suggestion, never shown inline
238 SuggestionStyle::ShowAlways,
239 ].contains(&sugg.style)
241 let substitution = &sugg.substitutions[0].parts[0].snippet.trim();
242 let msg = if substitution.len() == 0 || sugg.style.hide_inline() {
243 // This substitution is only removal OR we explicitly don't want to show the
244 // code inline (`hide_inline`). Therefore, we don't show the substitution.
245 format!("help: {}", sugg.msg)
247 // Show the default suggestion text with the substitution
253 .map(|sm| is_case_difference(
256 sugg.substitutions[0].parts[0].span,
260 " (notice the capitalization)"
267 primary_span.push_span_label(sugg.substitutions[0].parts[0].span, msg);
269 // We return only the modified primary_span
272 // if there are multiple suggestions, print them all in full
273 // to be consistent. We could try to figure out if we can
274 // make one (or the first one) inline, but that would give
275 // undue importance to a semi-random suggestion
276 (primary_span, &diag.suggestions)
279 (primary_span, &diag.suggestions)
283 // This does a small "fix" for multispans by looking to see if it can find any that
284 // point directly at <*macros>. Since these are often difficult to read, this
285 // will change the span to point at the use site.
286 fn fix_multispans_in_std_macros(
288 source_map: &Option<Lrc<SourceMap>>,
289 span: &mut MultiSpan,
290 children: &mut Vec<SubDiagnostic>,
294 let mut spans_updated = self.fix_multispan_in_std_macros(source_map, span, backtrace);
295 for child in children.iter_mut() {
297 self.fix_multispan_in_std_macros(source_map, &mut child.span, backtrace);
299 let msg = if level == &Error {
300 "this error originates in a macro outside of the current crate \
301 (in Nightly builds, run with -Z external-macro-backtrace \
305 "this warning originates in a macro outside of the current crate \
306 (in Nightly builds, run with -Z external-macro-backtrace \
312 children.push(SubDiagnostic {
314 message: vec![(msg, Style::NoStyle)],
315 span: MultiSpan::new(),
321 // This "fixes" MultiSpans that contain Spans that are pointing to locations inside of
322 // <*macros>. Since these locations are often difficult to read, we move these Spans from
323 // <*macros> to their corresponding use site.
324 fn fix_multispan_in_std_macros(
326 source_map: &Option<Lrc<SourceMap>>,
327 span: &mut MultiSpan,
328 always_backtrace: bool,
330 let sm = match source_map {
332 None => return false,
335 let mut before_after: Vec<(Span, Span)> = vec![];
336 let mut new_labels: Vec<(Span, String)> = vec![];
338 // First, find all the spans in <*macros> and point instead at their use site
339 for sp in span.primary_spans() {
343 let call_sp = sm.call_span_if_macro(*sp);
344 if call_sp != *sp && !always_backtrace {
345 before_after.push((*sp, call_sp));
347 let macro_backtrace: Vec<_> = sp.macro_backtrace().collect();
348 let backtrace_len = macro_backtrace.len();
349 for (i, trace) in macro_backtrace.iter().rev().enumerate() {
350 // Only show macro locations that are local
351 // and display them like a span_note
352 if trace.def_site.is_dummy() {
355 if always_backtrace {
359 "in this expansion of `{}`{}",
361 if backtrace_len > 2 {
362 // if backtrace_len == 1 it'll be pointed
363 // at by "in this macro invocation"
364 format!(" (#{})", i + 1)
371 // Check to make sure we're not in any <*macros>
372 if !sm.span_to_filename(trace.def_site).is_macros()
373 && matches!(trace.kind, ExpnKind::Macro(MacroKind::Bang, _))
379 "in this macro invocation{}",
380 if backtrace_len > 2 && always_backtrace {
381 // only specify order when the macro
382 // backtrace is multiple levels deep
383 format!(" (#{})", i + 1)
389 if !always_backtrace {
395 for (label_span, label_text) in new_labels {
396 span.push_span_label(label_span, label_text);
398 for sp_label in span.span_labels() {
399 if sp_label.span.is_dummy() {
402 if sm.span_to_filename(sp_label.span.clone()).is_macros() && !always_backtrace {
403 if let Some(use_site) = sp_label.span.macro_backtrace().last() {
404 before_after.push((sp_label.span, use_site.call_site));
408 // After we have them, make sure we replace these 'bad' def sites with their use sites
409 let spans_updated = !before_after.is_empty();
410 for (before, after) in before_after {
411 span.replace(before, after);
418 impl Emitter for EmitterWriter {
419 fn source_map(&self) -> Option<&Lrc<SourceMap>> {
423 fn emit_diagnostic(&mut self, diag: &Diagnostic) {
424 let mut children = diag.children.clone();
425 let (mut primary_span, suggestions) = self.primary_span_formatted(&diag);
427 self.fix_multispans_in_std_macros(
432 self.external_macro_backtrace,
435 self.emit_messages_default(
437 &diag.styled_message(),
445 fn should_show_explain(&self) -> bool {
450 /// An emitter that does nothing when emitting a diagnostic.
451 pub struct SilentEmitter;
453 impl Emitter for SilentEmitter {
454 fn source_map(&self) -> Option<&Lrc<SourceMap>> {
457 fn emit_diagnostic(&mut self, _: &Diagnostic) {}
460 /// Maximum number of lines we will print for each error; arbitrary.
461 pub const MAX_HIGHLIGHT_LINES: usize = 6;
462 /// Maximum number of lines we will print for a multiline suggestion; arbitrary.
464 /// This should be replaced with a more involved mechanism to output multiline suggestions that
465 /// more closely mimmics the regular diagnostic output, where irrelevant code lines are elided.
466 pub const MAX_SUGGESTION_HIGHLIGHT_LINES: usize = 6;
467 /// Maximum number of suggestions to be shown
469 /// Arbitrary, but taken from trait import suggestion limit
470 pub const MAX_SUGGESTIONS: usize = 4;
472 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
473 pub enum ColorConfig {
480 fn to_color_choice(self) -> ColorChoice {
482 ColorConfig::Always => {
483 if atty::is(atty::Stream::Stderr) {
486 ColorChoice::AlwaysAnsi
489 ColorConfig::Never => ColorChoice::Never,
490 ColorConfig::Auto if atty::is(atty::Stream::Stderr) => ColorChoice::Auto,
491 ColorConfig::Auto => ColorChoice::Never,
494 fn suggests_using_colors(self) -> bool {
496 ColorConfig::Always | ColorConfig::Auto => true,
497 ColorConfig::Never => false,
502 /// Handles the writing of `HumanReadableErrorType::Default` and `HumanReadableErrorType::Short`
503 pub struct EmitterWriter {
505 sm: Option<Lrc<SourceMap>>,
509 terminal_width: Option<usize>,
511 external_macro_backtrace: bool,
515 pub struct FileWithAnnotatedLines {
516 pub file: Lrc<SourceFile>,
517 pub lines: Vec<Line>,
518 multiline_depth: usize,
523 color_config: ColorConfig,
524 source_map: Option<Lrc<SourceMap>>,
527 terminal_width: Option<usize>,
528 external_macro_backtrace: bool,
530 let dst = Destination::from_stderr(color_config);
538 external_macro_backtrace,
543 dst: Box<dyn Write + Send>,
544 source_map: Option<Lrc<SourceMap>>,
548 terminal_width: Option<usize>,
549 external_macro_backtrace: bool,
552 dst: Raw(dst, colored),
558 external_macro_backtrace,
562 pub fn ui_testing(mut self, ui_testing: bool) -> Self {
563 self.ui_testing = ui_testing;
567 fn maybe_anonymized(&self, line_num: usize) -> String {
568 if self.ui_testing { ANONYMIZED_LINE_NUM.to_string() } else { line_num.to_string() }
573 buffer: &mut StyledBuffer,
581 let line_len = source_string.len();
582 // Create the source line we will highlight.
583 let left = margin.left(line_len);
584 let right = margin.right(line_len);
585 // On long lines, we strip the source line, accounting for unicode.
587 let code: String = source_string
591 // Make sure that the trimming on the right will fall within the terminal width.
592 // FIXME: `unicode_width` sometimes disagrees with terminals on how wide a `char` is.
593 // For now, just accept that sometimes the code line will be longer than desired.
594 let next = unicode_width::UnicodeWidthChar::width(*ch).unwrap_or(1);
595 if taken + next > right - left {
602 buffer.puts(line_offset, code_offset, &code, Style::Quotation);
603 if margin.was_cut_left() {
604 // We have stripped some code/whitespace from the beginning, make it clear.
605 buffer.puts(line_offset, code_offset, "...", Style::LineNumber);
607 if margin.was_cut_right(line_len) {
608 // We have stripped some code after the right-most span end, make it clear we did so.
609 buffer.puts(line_offset, code_offset + taken - 3, "...", Style::LineNumber);
611 buffer.puts(line_offset, 0, &self.maybe_anonymized(line_index), Style::LineNumber);
613 draw_col_separator(buffer, line_offset, width_offset - 2);
616 fn render_source_line(
618 buffer: &mut StyledBuffer,
619 file: Lrc<SourceFile>,
624 ) -> Vec<(usize, Style)> {
630 // | secondary span label
632 // ^^ ^ ^^^ ^^^^ ^^^ we don't care about code too far to the right of a span, we trim it
634 // | | | actual code found in your source code and the spans we use to mark it
635 // | | when there's too much wasted space to the left, trim it
636 // | vertical divider between the column number and the code
639 if line.line_index == 0 {
643 let source_string = match file.get_line(line.line_index - 1) {
645 None => return Vec::new(),
648 let line_offset = buffer.num_lines();
650 let left = margin.left(source_string.len()); // Left trim
651 // Account for unicode characters of width !=0 that were removed.
652 let left = source_string
655 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
668 // Special case when there's only one annotation involved, it is the start of a multiline
669 // span and there's no text at the beginning of the code line. Instead of doing the whole
678 // we simplify the output to:
684 if let [ann] = &line.annotations[..] {
685 if let AnnotationType::MultilineStart(depth) = ann.annotation_type {
686 if source_string.chars().take(ann.start_col).all(|c| c.is_whitespace()) {
687 let style = if ann.is_primary {
688 Style::UnderlinePrimary
690 Style::UnderlineSecondary
692 buffer.putc(line_offset, width_offset + depth - 1, '/', style);
693 return vec![(depth, style)];
698 // We want to display like this:
700 // vec.push(vec.pop().unwrap());
701 // --- ^^^ - previous borrow ends here
703 // | error occurs here
704 // previous borrow of `vec` occurs here
706 // But there are some weird edge cases to be aware of:
708 // vec.push(vec.pop().unwrap());
709 // -------- - previous borrow ends here
711 // |this makes no sense
712 // previous borrow of `vec` occurs here
714 // For this reason, we group the lines into "highlight lines"
715 // and "annotations lines", where the highlight lines have the `^`.
717 // Sort the annotations by (start, end col)
718 // The labels are reversed, sort and then reversed again.
719 // Consider a list of annotations (A1, A2, C1, C2, B1, B2) where
720 // the letter signifies the span. Here we are only sorting by the
721 // span and hence, the order of the elements with the same span will
722 // not change. On reversing the ordering (|a, b| but b.cmp(a)), you get
723 // (C1, C2, B1, B2, A1, A2). All the elements with the same span are
724 // still ordered first to last, but all the elements with different
725 // spans are ordered by their spans in last to first order. Last to
726 // first order is important, because the jiggly lines and | are on
727 // the left, so the rightmost span needs to be rendered first,
728 // otherwise the lines would end up needing to go over a message.
730 let mut annotations = line.annotations.clone();
731 annotations.sort_by_key(|a| Reverse(a.start_col));
733 // First, figure out where each label will be positioned.
735 // In the case where you have the following annotations:
737 // vec.push(vec.pop().unwrap());
738 // -------- - previous borrow ends here [C]
740 // |this makes no sense [B]
741 // previous borrow of `vec` occurs here [A]
743 // `annotations_position` will hold [(2, A), (1, B), (0, C)].
745 // We try, when possible, to stick the rightmost annotation at the end
746 // of the highlight line:
748 // vec.push(vec.pop().unwrap());
749 // --- --- - previous borrow ends here
751 // But sometimes that's not possible because one of the other
752 // annotations overlaps it. For example, from the test
753 // `span_overlap_label`, we have the following annotations
754 // (written on distinct lines for clarity):
760 // In this case, we can't stick the rightmost-most label on
761 // the highlight line, or we would get:
768 // which is totally weird. Instead we want:
776 // which is...less weird, at least. In fact, in general, if
777 // the rightmost span overlaps with any other span, we should
778 // use the "hang below" version, so we can at least make it
779 // clear where the span *starts*. There's an exception for this
780 // logic, when the labels do not have a message:
795 let mut annotations_position = vec![];
796 let mut line_len = 0;
798 for (i, annotation) in annotations.iter().enumerate() {
799 for (j, next) in annotations.iter().enumerate() {
800 if overlaps(next, annotation, 0) // This label overlaps with another one and both
801 && annotation.has_label() // take space (they have text and are not
802 && j > i // multiline lines).
804 // We're currently on the first line, move the label one line down
806 // If we're overlapping with an un-labelled annotation with the same span
807 // we can just merge them in the output
808 if next.start_col == annotation.start_col
809 && next.end_col == annotation.end_col
815 // This annotation needs a new line in the output.
820 annotations_position.push((p, annotation));
821 for (j, next) in annotations.iter().enumerate() {
823 let l = next.label.as_ref().map_or(0, |label| label.len() + 2);
824 if (overlaps(next, annotation, l) // Do not allow two labels to be in the same
825 // line if they overlap including padding, to
826 // avoid situations like:
833 && annotation.has_label() // Both labels must have some text, otherwise
834 && next.has_label()) // they are not overlapping.
835 // Do not add a new line if this annotation
836 // or the next are vertical line placeholders.
837 || (annotation.takes_space() // If either this or the next annotation is
838 && next.has_label()) // multiline start/end, move it to a new line
839 || (annotation.has_label() // so as not to overlap the orizontal lines.
840 && next.takes_space())
841 || (annotation.takes_space() && next.takes_space())
842 || (overlaps(next, annotation, l)
843 && next.end_col <= annotation.end_col
848 // This annotation needs a new line in the output.
854 line_len = max(line_len, p);
861 // If there are no annotations or the only annotations on this line are
862 // MultilineLine, then there's only code being shown, stop processing.
863 if line.annotations.iter().all(|a| a.is_line()) {
867 // Write the column separator.
869 // After this we will have:
878 for pos in 0..=line_len {
879 draw_col_separator(buffer, line_offset + pos + 1, width_offset - 2);
880 buffer.putc(line_offset + pos + 1, width_offset - 2, '|', Style::LineNumber);
883 // Write the horizontal lines for multiline annotations
884 // (only the first and last lines need this).
886 // After this we will have:
895 for &(pos, annotation) in &annotations_position {
896 let style = if annotation.is_primary {
897 Style::UnderlinePrimary
899 Style::UnderlineSecondary
902 match annotation.annotation_type {
903 AnnotationType::MultilineStart(depth) | AnnotationType::MultilineEnd(depth) => {
908 width_offset + depth,
909 code_offset + annotation.start_col - left,
914 buffer.set_style_range(
916 code_offset + annotation.start_col - left,
917 code_offset + annotation.end_col - left,
919 annotation.is_primary,
926 // Write the vertical lines for labels that are on a different line as the underline.
928 // After this we will have:
937 for &(pos, annotation) in &annotations_position {
938 let style = if annotation.is_primary {
939 Style::UnderlinePrimary
941 Style::UnderlineSecondary
945 if pos > 1 && (annotation.has_label() || annotation.takes_space()) {
946 for p in line_offset + 1..=line_offset + pos {
949 (code_offset + annotation.start_col).saturating_sub(left),
955 match annotation.annotation_type {
956 AnnotationType::MultilineStart(depth) => {
957 for p in line_offset + pos + 1..line_offset + line_len + 2 {
958 buffer.putc(p, width_offset + depth - 1, '|', style);
961 AnnotationType::MultilineEnd(depth) => {
962 for p in line_offset..=line_offset + pos {
963 buffer.putc(p, width_offset + depth - 1, '|', style);
970 // Write the labels on the annotations that actually have a label.
972 // After this we will have:
977 // | something about `foo`
981 for &(pos, annotation) in &annotations_position {
983 if annotation.is_primary { Style::LabelPrimary } else { Style::LabelSecondary };
984 let (pos, col) = if pos == 0 {
985 (pos + 1, (annotation.end_col + 1).saturating_sub(left))
987 (pos + 2, annotation.start_col.saturating_sub(left))
989 if let Some(ref label) = annotation.label {
990 buffer.puts(line_offset + pos, code_offset + col, &label, style);
994 // Sort from biggest span to smallest span so that smaller spans are
995 // represented in the output:
1000 // | | something about `foo`
1001 // | something about `fn foo()`
1002 annotations_position.sort_by_key(|(_, ann)| {
1003 // Decreasing order. When annotations share the same length, prefer `Primary`.
1004 (Reverse(ann.len()), ann.is_primary)
1007 // Write the underlines.
1009 // After this we will have:
1014 // | something about `foo`
1018 for &(_, annotation) in &annotations_position {
1019 let (underline, style) = if annotation.is_primary {
1020 ('^', Style::UnderlinePrimary)
1022 ('-', Style::UnderlineSecondary)
1024 for p in annotation.start_col..annotation.end_col {
1027 (code_offset + p).saturating_sub(left),
1033 annotations_position
1035 .filter_map(|&(_, annotation)| match annotation.annotation_type {
1036 AnnotationType::MultilineStart(p) | AnnotationType::MultilineEnd(p) => {
1037 let style = if annotation.is_primary {
1040 Style::LabelSecondary
1046 .collect::<Vec<_>>()
1049 fn get_multispan_max_line_num(&mut self, msp: &MultiSpan) -> usize {
1050 let sm = match self.sm {
1056 for primary_span in msp.primary_spans() {
1057 if !primary_span.is_dummy() {
1058 let hi = sm.lookup_char_pos(primary_span.hi());
1059 max = (hi.line).max(max);
1062 if !self.short_message {
1063 for span_label in msp.span_labels() {
1064 if !span_label.span.is_dummy() {
1065 let hi = sm.lookup_char_pos(span_label.span.hi());
1066 max = (hi.line).max(max);
1074 fn get_max_line_num(&mut self, span: &MultiSpan, children: &[SubDiagnostic]) -> usize {
1075 let primary = self.get_multispan_max_line_num(span);
1078 .map(|sub| self.get_multispan_max_line_num(&sub.span))
1084 /// Adds a left margin to every line but the first, given a padding length and the label being
1085 /// displayed, keeping the provided highlighting.
1088 buffer: &mut StyledBuffer,
1089 msg: &[(String, Style)],
1092 override_style: Option<Style>,
1094 // The extra 5 ` ` is padding that's always needed to align to the `note: `:
1097 // --> file.rs:13:20
1102 // = note: multiline
1107 // | | length of label
1109 // `max_line_num_len`
1110 let padding = " ".repeat(padding + label.len() + 5);
1112 /// Returns `override` if it is present and `style` is `NoStyle` or `style` otherwise
1113 fn style_or_override(style: Style, override_: Option<Style>) -> Style {
1114 match (style, override_) {
1115 (Style::NoStyle, Some(override_)) => override_,
1120 let mut line_number = 0;
1122 // Provided the following diagnostic message:
1126 // ("highlighted multiline\nstring to\nsee how it ", Style::NoStyle),
1127 // ("looks", Style::Highlight),
1128 // ("with\nvery ", Style::NoStyle),
1129 // ("weird", Style::Highlight),
1130 // (" formats\n", Style::NoStyle),
1131 // ("see?", Style::Highlight),
1134 // the expected output on a note is (* surround the highlighted text)
1136 // = note: highlighted multiline
1138 // see how it *looks* with
1139 // very *weird* formats
1141 for &(ref text, ref style) in msg.iter() {
1142 let lines = text.split('\n').collect::<Vec<_>>();
1143 if lines.len() > 1 {
1144 for (i, line) in lines.iter().enumerate() {
1147 buffer.append(line_number, &padding, Style::NoStyle);
1149 buffer.append(line_number, line, style_or_override(*style, override_style));
1152 buffer.append(line_number, text, style_or_override(*style, override_style));
1157 fn emit_message_default(
1160 msg: &[(String, Style)],
1161 code: &Option<DiagnosticId>,
1163 max_line_num_len: usize,
1165 ) -> io::Result<()> {
1166 let mut buffer = StyledBuffer::new();
1167 let header_style = if is_secondary { Style::HeaderMsg } else { Style::MainHeaderMsg };
1169 if !msp.has_primary_spans() && !msp.has_span_labels() && is_secondary && !self.short_message
1171 // This is a secondary message with no span info
1172 for _ in 0..max_line_num_len {
1173 buffer.prepend(0, " ", Style::NoStyle);
1175 draw_note_separator(&mut buffer, 0, max_line_num_len + 1);
1176 if *level != Level::FailureNote {
1177 let level_str = level.to_string();
1178 if !level_str.is_empty() {
1179 buffer.append(0, &level_str, Style::MainHeaderMsg);
1180 buffer.append(0, ": ", Style::NoStyle);
1183 self.msg_to_buffer(&mut buffer, msg, max_line_num_len, "note", None);
1185 let level_str = level.to_string();
1186 // The failure note level itself does not provide any useful diagnostic information
1187 if *level != Level::FailureNote && !level_str.is_empty() {
1188 buffer.append(0, &level_str, Style::Level(*level));
1190 // only render error codes, not lint codes
1191 if let Some(DiagnosticId::Error(ref code)) = *code {
1192 buffer.append(0, "[", Style::Level(*level));
1193 buffer.append(0, &code, Style::Level(*level));
1194 buffer.append(0, "]", Style::Level(*level));
1196 if *level != Level::FailureNote && !level_str.is_empty() {
1197 buffer.append(0, ": ", header_style);
1199 for &(ref text, _) in msg.iter() {
1200 buffer.append(0, text, header_style);
1204 let mut annotated_files = FileWithAnnotatedLines::collect_annotations(msp, &self.sm);
1206 // Make sure our primary file comes first
1207 let (primary_lo, sm) = if let (Some(sm), Some(ref primary_span)) =
1208 (self.sm.as_ref(), msp.primary_span().as_ref())
1210 if !primary_span.is_dummy() {
1211 (sm.lookup_char_pos(primary_span.lo()), sm)
1213 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1217 // If we don't have span information, emit and exit
1218 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1222 annotated_files.binary_search_by(|x| x.file.name.cmp(&primary_lo.file.name))
1224 annotated_files.swap(0, pos);
1227 // Print out the annotate source lines that correspond with the error
1228 for annotated_file in annotated_files {
1229 // we can't annotate anything if the source is unavailable.
1230 if !sm.ensure_source_file_source_present(annotated_file.file.clone()) {
1234 // print out the span location and spacer before we print the annotated source
1235 // to do this, we need to know if this span will be primary
1236 let is_primary = primary_lo.file.name == annotated_file.file.name;
1238 let loc = primary_lo.clone();
1239 if !self.short_message {
1240 // remember where we are in the output buffer for easy reference
1241 let buffer_msg_line_offset = buffer.num_lines();
1243 buffer.prepend(buffer_msg_line_offset, "--> ", Style::LineNumber);
1245 buffer_msg_line_offset,
1249 sm.doctest_offset_line(&loc.file.name, loc.line),
1252 Style::LineAndColumn,
1254 for _ in 0..max_line_num_len {
1255 buffer.prepend(buffer_msg_line_offset, " ", Style::NoStyle);
1263 sm.doctest_offset_line(&loc.file.name, loc.line),
1266 Style::LineAndColumn,
1269 } else if !self.short_message {
1270 // remember where we are in the output buffer for easy reference
1271 let buffer_msg_line_offset = buffer.num_lines();
1274 draw_col_separator(&mut buffer, buffer_msg_line_offset, max_line_num_len + 1);
1276 // Then, the secondary file indicator
1277 buffer.prepend(buffer_msg_line_offset + 1, "::: ", Style::LineNumber);
1278 let loc = if let Some(first_line) = annotated_file.lines.first() {
1279 let col = if let Some(first_annotation) = first_line.annotations.first() {
1280 format!(":{}", first_annotation.start_col + 1)
1286 annotated_file.file.name,
1287 sm.doctest_offset_line(&annotated_file.file.name, first_line.line_index),
1291 annotated_file.file.name.to_string()
1293 buffer.append(buffer_msg_line_offset + 1, &loc, Style::LineAndColumn);
1294 for _ in 0..max_line_num_len {
1295 buffer.prepend(buffer_msg_line_offset + 1, " ", Style::NoStyle);
1299 if !self.short_message {
1300 // Put in the spacer between the location and annotated source
1301 let buffer_msg_line_offset = buffer.num_lines();
1302 draw_col_separator_no_space(
1304 buffer_msg_line_offset,
1305 max_line_num_len + 1,
1308 // Contains the vertical lines' positions for active multiline annotations
1309 let mut multilines = FxHashMap::default();
1311 // Get the left-side margin to remove it
1312 let mut whitespace_margin = std::usize::MAX;
1313 for line_idx in 0..annotated_file.lines.len() {
1314 let file = annotated_file.file.clone();
1315 let line = &annotated_file.lines[line_idx];
1316 if let Some(source_string) = file.get_line(line.line_index - 1) {
1317 let leading_whitespace =
1318 source_string.chars().take_while(|c| c.is_whitespace()).count();
1319 if source_string.chars().any(|c| !c.is_whitespace()) {
1320 whitespace_margin = min(whitespace_margin, leading_whitespace);
1324 if whitespace_margin == std::usize::MAX {
1325 whitespace_margin = 0;
1328 // Left-most column any visible span points at.
1329 let mut span_left_margin = std::usize::MAX;
1330 for line in &annotated_file.lines {
1331 for ann in &line.annotations {
1332 span_left_margin = min(span_left_margin, ann.start_col);
1333 span_left_margin = min(span_left_margin, ann.end_col);
1336 if span_left_margin == std::usize::MAX {
1337 span_left_margin = 0;
1340 // Right-most column any visible span points at.
1341 let mut span_right_margin = 0;
1342 let mut label_right_margin = 0;
1343 let mut max_line_len = 0;
1344 for line in &annotated_file.lines {
1347 annotated_file.file.get_line(line.line_index - 1).map_or(0, |s| s.len()),
1349 for ann in &line.annotations {
1350 span_right_margin = max(span_right_margin, ann.start_col);
1351 span_right_margin = max(span_right_margin, ann.end_col);
1352 // FIXME: account for labels not in the same line
1353 let label_right = ann.label.as_ref().map_or(0, |l| l.len() + 1);
1354 label_right_margin = max(label_right_margin, ann.end_col + label_right);
1358 let width_offset = 3 + max_line_num_len;
1359 let code_offset = if annotated_file.multiline_depth == 0 {
1362 width_offset + annotated_file.multiline_depth + 1
1365 let column_width = if let Some(width) = self.terminal_width {
1366 width.saturating_sub(code_offset)
1367 } else if self.ui_testing {
1370 termize::dimensions()
1371 .map(|(w, _)| w.saturating_sub(code_offset))
1372 .unwrap_or(std::usize::MAX)
1375 let margin = Margin::new(
1384 // Next, output the annotate source for this file
1385 for line_idx in 0..annotated_file.lines.len() {
1386 let previous_buffer_line = buffer.num_lines();
1388 let depths = self.render_source_line(
1390 annotated_file.file.clone(),
1391 &annotated_file.lines[line_idx],
1397 let mut to_add = FxHashMap::default();
1399 for (depth, style) in depths {
1400 if multilines.get(&depth).is_some() {
1401 multilines.remove(&depth);
1403 to_add.insert(depth, style);
1407 // Set the multiline annotation vertical lines to the left of
1408 // the code in this line.
1409 for (depth, style) in &multilines {
1410 for line in previous_buffer_line..buffer.num_lines() {
1411 draw_multiline_line(&mut buffer, line, width_offset, *depth, *style);
1414 // check to see if we need to print out or elide lines that come between
1415 // this annotated line and the next one.
1416 if line_idx < (annotated_file.lines.len() - 1) {
1417 let line_idx_delta = annotated_file.lines[line_idx + 1].line_index
1418 - annotated_file.lines[line_idx].line_index;
1419 if line_idx_delta > 2 {
1420 let last_buffer_line_num = buffer.num_lines();
1421 buffer.puts(last_buffer_line_num, 0, "...", Style::LineNumber);
1423 // Set the multiline annotation vertical lines on `...` bridging line.
1424 for (depth, style) in &multilines {
1425 draw_multiline_line(
1427 last_buffer_line_num,
1433 } else if line_idx_delta == 2 {
1434 let unannotated_line = annotated_file
1436 .get_line(annotated_file.lines[line_idx].line_index)
1437 .unwrap_or_else(|| Cow::from(""));
1439 let last_buffer_line_num = buffer.num_lines();
1444 annotated_file.lines[line_idx + 1].line_index - 1,
1445 last_buffer_line_num,
1451 for (depth, style) in &multilines {
1452 draw_multiline_line(
1454 last_buffer_line_num,
1463 multilines.extend(&to_add);
1468 // final step: take our styled buffer, render it, then output it
1469 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1474 fn emit_suggestion_default(
1476 suggestion: &CodeSuggestion,
1478 max_line_num_len: usize,
1479 ) -> io::Result<()> {
1480 let sm = match self.sm {
1482 None => return Ok(()),
1485 // Render the replacements for each suggestion
1486 let suggestions = suggestion.splice_lines(&**sm);
1488 if suggestions.is_empty() {
1489 // Suggestions coming from macros can have malformed spans. This is a heavy handed
1490 // approach to avoid ICEs by ignoring the suggestion outright.
1494 let mut buffer = StyledBuffer::new();
1496 // Render the suggestion message
1497 let level_str = level.to_string();
1498 if !level_str.is_empty() {
1499 buffer.append(0, &level_str, Style::Level(*level));
1500 buffer.append(0, ": ", Style::HeaderMsg);
1504 &[(suggestion.msg.to_owned(), Style::NoStyle)],
1507 Some(Style::HeaderMsg),
1510 let mut row_num = 2;
1511 let mut notice_capitalization = false;
1512 for (complete, parts, only_capitalization) in suggestions.iter().take(MAX_SUGGESTIONS) {
1513 notice_capitalization |= only_capitalization;
1514 // Only show underline if the suggestion spans a single line and doesn't cover the
1515 // entirety of the code output. If you have multiple replacements in the same line
1516 // of code, show the underline.
1517 let show_underline = !(parts.len() == 1 && parts[0].snippet.trim() == complete.trim())
1518 && complete.lines().count() == 1;
1521 .span_to_lines(parts[0].span)
1522 .expect("span_to_lines failed when emitting suggestion");
1524 assert!(!lines.lines.is_empty());
1526 let line_start = sm.lookup_char_pos(parts[0].span.lo()).line;
1527 draw_col_separator_no_space(&mut buffer, 1, max_line_num_len + 1);
1528 let mut line_pos = 0;
1529 let mut lines = complete.lines();
1530 for line in lines.by_ref().take(MAX_SUGGESTION_HIGHLIGHT_LINES) {
1531 // Print the span column to avoid confusion
1535 &self.maybe_anonymized(line_start + line_pos),
1538 // print the suggestion
1539 draw_col_separator(&mut buffer, row_num, max_line_num_len + 1);
1540 buffer.append(row_num, line, Style::NoStyle);
1545 // This offset and the ones below need to be signed to account for replacement code
1546 // that is shorter than the original code.
1547 let mut offsets: Vec<(usize, isize)> = Vec::new();
1548 // Only show an underline in the suggestions if the suggestion is not the
1549 // entirety of the code being shown and the displayed code is not multiline.
1551 draw_col_separator(&mut buffer, row_num, max_line_num_len + 1);
1553 let span_start_pos = sm.lookup_char_pos(part.span.lo()).col_display;
1554 let span_end_pos = sm.lookup_char_pos(part.span.hi()).col_display;
1556 // Do not underline the leading...
1557 let start = part.snippet.len().saturating_sub(part.snippet.trim_start().len());
1558 // ...or trailing spaces. Account for substitutions containing unicode
1560 let sub_len: usize = part
1564 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
1567 let offset: isize = offsets
1570 |(start, v)| if span_start_pos <= *start { None } else { Some(v) },
1573 let underline_start = (span_start_pos + start) as isize + offset;
1574 let underline_end = (span_start_pos + start + sub_len) as isize + offset;
1575 assert!(underline_start >= 0 && underline_end >= 0);
1576 for p in underline_start..underline_end {
1579 ((max_line_num_len + 3) as isize + p) as usize,
1581 Style::UnderlinePrimary,
1584 // underline removals too
1585 if underline_start == underline_end {
1586 for p in underline_start - 1..underline_start + 1 {
1589 ((max_line_num_len + 3) as isize + p) as usize,
1591 Style::UnderlineSecondary,
1596 // length of the code after substitution
1597 let full_sub_len = part
1600 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
1601 .sum::<usize>() as isize;
1603 // length of the code to be substituted
1604 let snippet_len = span_end_pos as isize - span_start_pos as isize;
1605 // For multiple substitutions, use the position *after* the previous
1606 // substitutions have happened, only when further substitutions are
1607 // located strictly after.
1608 offsets.push((span_end_pos, full_sub_len - snippet_len));
1613 // if we elided some lines, add an ellipsis
1614 if lines.next().is_some() {
1615 buffer.puts(row_num, max_line_num_len - 1, "...", Style::LineNumber);
1616 } else if !show_underline {
1617 draw_col_separator_no_space(&mut buffer, row_num, max_line_num_len + 1);
1621 if suggestions.len() > MAX_SUGGESTIONS {
1622 let others = suggestions.len() - MAX_SUGGESTIONS;
1623 let msg = format!("and {} other candidate{}", others, pluralize!(others));
1624 buffer.puts(row_num, max_line_num_len + 3, &msg, Style::NoStyle);
1625 } else if notice_capitalization {
1626 let msg = "notice the capitalization difference";
1627 buffer.puts(row_num, max_line_num_len + 3, &msg, Style::NoStyle);
1629 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1633 fn emit_messages_default(
1636 message: &[(String, Style)],
1637 code: &Option<DiagnosticId>,
1639 children: &[SubDiagnostic],
1640 suggestions: &[CodeSuggestion],
1642 let max_line_num_len = if self.ui_testing {
1643 ANONYMIZED_LINE_NUM.len()
1645 self.get_max_line_num(span, children).to_string().len()
1648 match self.emit_message_default(span, message, code, level, max_line_num_len, false) {
1650 if !children.is_empty()
1651 || suggestions.iter().any(|s| s.style != SuggestionStyle::CompletelyHidden)
1653 let mut buffer = StyledBuffer::new();
1654 if !self.short_message {
1655 draw_col_separator_no_space(&mut buffer, 0, max_line_num_len + 1);
1657 match emit_to_destination(
1664 Err(e) => panic!("failed to emit error: {}", e),
1667 if !self.short_message {
1668 for child in children {
1669 let span = child.render_span.as_ref().unwrap_or(&child.span);
1670 match self.emit_message_default(
1672 &child.styled_message(),
1678 Err(e) => panic!("failed to emit error: {}", e),
1682 for sugg in suggestions {
1683 if sugg.style == SuggestionStyle::CompletelyHidden {
1684 // do not display this suggestion, it is meant only for tools
1685 } else if sugg.style == SuggestionStyle::HideCodeAlways {
1686 match self.emit_message_default(
1688 &[(sugg.msg.to_owned(), Style::HeaderMsg)],
1694 Err(e) => panic!("failed to emit error: {}", e),
1698 match self.emit_suggestion_default(sugg, &Level::Help, max_line_num_len)
1700 Err(e) => panic!("failed to emit error: {}", e),
1707 Err(e) => panic!("failed to emit error: {}", e),
1710 let mut dst = self.dst.writable();
1711 match writeln!(dst) {
1712 Err(e) => panic!("failed to emit error: {}", e),
1713 _ => match dst.flush() {
1714 Err(e) => panic!("failed to emit error: {}", e),
1721 impl FileWithAnnotatedLines {
1722 /// Preprocess all the annotations so that they are grouped by file and by line number
1723 /// This helps us quickly iterate over the whole message (including secondary file spans)
1724 pub fn collect_annotations(
1726 source_map: &Option<Lrc<SourceMap>>,
1727 ) -> Vec<FileWithAnnotatedLines> {
1728 fn add_annotation_to_file(
1729 file_vec: &mut Vec<FileWithAnnotatedLines>,
1730 file: Lrc<SourceFile>,
1734 for slot in file_vec.iter_mut() {
1735 // Look through each of our files for the one we're adding to
1736 if slot.file.name == file.name {
1737 // See if we already have a line for it
1738 for line_slot in &mut slot.lines {
1739 if line_slot.line_index == line_index {
1740 line_slot.annotations.push(ann);
1744 // We don't have a line yet, create one
1745 slot.lines.push(Line { line_index, annotations: vec![ann] });
1750 // This is the first time we're seeing the file
1751 file_vec.push(FileWithAnnotatedLines {
1753 lines: vec![Line { line_index, annotations: vec![ann] }],
1758 let mut output = vec![];
1759 let mut multiline_annotations = vec![];
1761 if let Some(ref sm) = source_map {
1762 for span_label in msp.span_labels() {
1763 if span_label.span.is_dummy() {
1767 let lo = sm.lookup_char_pos(span_label.span.lo());
1768 let mut hi = sm.lookup_char_pos(span_label.span.hi());
1770 // Watch out for "empty spans". If we get a span like 6..6, we
1771 // want to just display a `^` at 6, so convert that to
1772 // 6..7. This is degenerate input, but it's best to degrade
1773 // gracefully -- and the parser likes to supply a span like
1774 // that for EOF, in particular.
1776 if lo.col_display == hi.col_display && lo.line == hi.line {
1777 hi.col_display += 1;
1780 if lo.line != hi.line {
1781 let ml = MultilineAnnotation {
1783 line_start: lo.line,
1785 start_col: lo.col_display,
1786 end_col: hi.col_display,
1787 is_primary: span_label.is_primary,
1788 label: span_label.label,
1789 overlaps_exactly: false,
1791 multiline_annotations.push((lo.file, ml));
1793 let ann = Annotation {
1794 start_col: lo.col_display,
1795 end_col: hi.col_display,
1796 is_primary: span_label.is_primary,
1797 label: span_label.label,
1798 annotation_type: AnnotationType::Singleline,
1800 add_annotation_to_file(&mut output, lo.file, lo.line, ann);
1805 // Find overlapping multiline annotations, put them at different depths
1806 multiline_annotations.sort_by_key(|&(_, ref ml)| (ml.line_start, ml.line_end));
1807 for (_, ann) in multiline_annotations.clone() {
1808 for (_, a) in multiline_annotations.iter_mut() {
1809 // Move all other multiline annotations overlapping with this one
1810 // one level to the right.
1811 if !(ann.same_span(a))
1812 && num_overlap(ann.line_start, ann.line_end, a.line_start, a.line_end, true)
1815 } else if ann.same_span(a) && &ann != a {
1816 a.overlaps_exactly = true;
1823 let mut max_depth = 0; // max overlapping multiline spans
1824 for (file, ann) in multiline_annotations {
1825 max_depth = max(max_depth, ann.depth);
1826 let mut end_ann = ann.as_end();
1827 if !ann.overlaps_exactly {
1828 // avoid output like
1850 add_annotation_to_file(&mut output, file.clone(), ann.line_start, ann.as_start());
1851 // 4 is the minimum vertical length of a multiline span when presented: two lines
1852 // of code and two lines of underline. This is not true for the special case where
1853 // the beginning doesn't have an underline, but the current logic seems to be
1854 // working correctly.
1855 let middle = min(ann.line_start + 4, ann.line_end);
1856 for line in ann.line_start + 1..middle {
1857 // Every `|` that joins the beginning of the span (`___^`) to the end (`|__^`).
1858 add_annotation_to_file(&mut output, file.clone(), line, ann.as_line());
1860 let line_end = ann.line_end - 1;
1861 if middle < line_end {
1862 add_annotation_to_file(&mut output, file.clone(), line_end, ann.as_line());
1865 end_ann.annotation_type = AnnotationType::Singleline;
1867 add_annotation_to_file(&mut output, file, ann.line_end, end_ann);
1869 for file_vec in output.iter_mut() {
1870 file_vec.multiline_depth = max_depth;
1876 fn draw_col_separator(buffer: &mut StyledBuffer, line: usize, col: usize) {
1877 buffer.puts(line, col, "| ", Style::LineNumber);
1880 fn draw_col_separator_no_space(buffer: &mut StyledBuffer, line: usize, col: usize) {
1881 draw_col_separator_no_space_with_style(buffer, line, col, Style::LineNumber);
1884 fn draw_col_separator_no_space_with_style(
1885 buffer: &mut StyledBuffer,
1890 buffer.putc(line, col, '|', style);
1894 buffer: &mut StyledBuffer,
1901 for col in col_from..col_to {
1902 buffer.putc(line, col, symbol, style);
1906 fn draw_note_separator(buffer: &mut StyledBuffer, line: usize, col: usize) {
1907 buffer.puts(line, col, "= ", Style::LineNumber);
1910 fn draw_multiline_line(
1911 buffer: &mut StyledBuffer,
1917 buffer.putc(line, offset + depth - 1, '|', style);
1927 let extra = if inclusive { 1 } else { 0 };
1928 (b_start..b_end + extra).contains(&a_start) || (a_start..a_end + extra).contains(&b_start)
1930 fn overlaps(a1: &Annotation, a2: &Annotation, padding: usize) -> bool {
1931 num_overlap(a1.start_col, a1.end_col + padding, a2.start_col, a2.end_col, false)
1934 fn emit_to_destination(
1935 rendered_buffer: &[Vec<StyledString>],
1937 dst: &mut Destination,
1938 short_message: bool,
1939 ) -> io::Result<()> {
1942 let mut dst = dst.writable();
1944 // In order to prevent error message interleaving, where multiple error lines get intermixed
1945 // when multiple compiler processes error simultaneously, we emit errors with additional
1948 // On Unix systems, we write into a buffered terminal rather than directly to a terminal. When
1949 // the .flush() is called we take the buffer created from the buffered writes and write it at
1950 // one shot. Because the Unix systems use ANSI for the colors, which is a text-based styling
1951 // scheme, this buffered approach works and maintains the styling.
1953 // On Windows, styling happens through calls to a terminal API. This prevents us from using the
1954 // same buffering approach. Instead, we use a global Windows mutex, which we acquire long
1955 // enough to output the full error message, then we release.
1956 let _buffer_lock = lock::acquire_global_lock("rustc_errors");
1957 for (pos, line) in rendered_buffer.iter().enumerate() {
1959 dst.apply_style(lvl.clone(), part.style)?;
1960 write!(dst, "{}", part.text)?;
1963 if !short_message && (!lvl.is_failure_note() || pos != rendered_buffer.len() - 1) {
1971 pub enum Destination {
1972 Terminal(StandardStream),
1973 Buffered(BufferWriter),
1974 // The bool denotes whether we should be emitting ansi color codes or not
1975 Raw(Box<(dyn Write + Send)>, bool),
1978 pub enum WritableDst<'a> {
1979 Terminal(&'a mut StandardStream),
1980 Buffered(&'a mut BufferWriter, Buffer),
1981 Raw(&'a mut (dyn Write + Send)),
1982 ColoredRaw(Ansi<&'a mut (dyn Write + Send)>),
1986 fn from_stderr(color: ColorConfig) -> Destination {
1987 let choice = color.to_color_choice();
1988 // On Windows we'll be performing global synchronization on the entire
1989 // system for emitting rustc errors, so there's no need to buffer
1992 // On non-Windows we rely on the atomicity of `write` to ensure errors
1993 // don't get all jumbled up.
1995 Terminal(StandardStream::stderr(choice))
1997 Buffered(BufferWriter::stderr(choice))
2001 fn writable(&mut self) -> WritableDst<'_> {
2003 Destination::Terminal(ref mut t) => WritableDst::Terminal(t),
2004 Destination::Buffered(ref mut t) => {
2005 let buf = t.buffer();
2006 WritableDst::Buffered(t, buf)
2008 Destination::Raw(ref mut t, false) => WritableDst::Raw(t),
2009 Destination::Raw(ref mut t, true) => WritableDst::ColoredRaw(Ansi::new(t)),
2014 impl<'a> WritableDst<'a> {
2015 fn apply_style(&mut self, lvl: Level, style: Style) -> io::Result<()> {
2016 let mut spec = ColorSpec::new();
2018 Style::LineAndColumn => {}
2019 Style::LineNumber => {
2020 spec.set_bold(true);
2021 spec.set_intense(true);
2023 spec.set_fg(Some(Color::Cyan));
2025 spec.set_fg(Some(Color::Blue));
2028 Style::Quotation => {}
2029 Style::MainHeaderMsg => {
2030 spec.set_bold(true);
2032 spec.set_intense(true).set_fg(Some(Color::White));
2035 Style::UnderlinePrimary | Style::LabelPrimary => {
2037 spec.set_bold(true);
2039 Style::UnderlineSecondary | Style::LabelSecondary => {
2040 spec.set_bold(true).set_intense(true);
2042 spec.set_fg(Some(Color::Cyan));
2044 spec.set_fg(Some(Color::Blue));
2047 Style::HeaderMsg | Style::NoStyle => {}
2048 Style::Level(lvl) => {
2050 spec.set_bold(true);
2052 Style::Highlight => {
2053 spec.set_bold(true);
2056 self.set_color(&spec)
2059 fn set_color(&mut self, color: &ColorSpec) -> io::Result<()> {
2061 WritableDst::Terminal(ref mut t) => t.set_color(color),
2062 WritableDst::Buffered(_, ref mut t) => t.set_color(color),
2063 WritableDst::ColoredRaw(ref mut t) => t.set_color(color),
2064 WritableDst::Raw(_) => Ok(()),
2068 fn reset(&mut self) -> io::Result<()> {
2070 WritableDst::Terminal(ref mut t) => t.reset(),
2071 WritableDst::Buffered(_, ref mut t) => t.reset(),
2072 WritableDst::ColoredRaw(ref mut t) => t.reset(),
2073 WritableDst::Raw(_) => Ok(()),
2078 impl<'a> Write for WritableDst<'a> {
2079 fn write(&mut self, bytes: &[u8]) -> io::Result<usize> {
2081 WritableDst::Terminal(ref mut t) => t.write(bytes),
2082 WritableDst::Buffered(_, ref mut buf) => buf.write(bytes),
2083 WritableDst::Raw(ref mut w) => w.write(bytes),
2084 WritableDst::ColoredRaw(ref mut t) => t.write(bytes),
2088 fn flush(&mut self) -> io::Result<()> {
2090 WritableDst::Terminal(ref mut t) => t.flush(),
2091 WritableDst::Buffered(_, ref mut buf) => buf.flush(),
2092 WritableDst::Raw(ref mut w) => w.flush(),
2093 WritableDst::ColoredRaw(ref mut w) => w.flush(),
2098 impl<'a> Drop for WritableDst<'a> {
2099 fn drop(&mut self) {
2101 WritableDst::Buffered(ref mut dst, ref mut buf) => {
2102 drop(dst.print(buf));
2109 /// Whether the original and suggested code are visually similar enough to warrant extra wording.
2110 pub fn is_case_difference(sm: &SourceMap, suggested: &str, sp: Span) -> bool {
2111 // FIXME: this should probably be extended to also account for `FO0` → `FOO` and unicode.
2112 let found = match sm.span_to_snippet(sp) {
2113 Ok(snippet) => snippet,
2115 warn!("Invalid span {:?}. Err={:?}", sp, e);
2119 let ascii_confusables = &['c', 'f', 'i', 'k', 'o', 's', 'u', 'v', 'w', 'x', 'y', 'z'];
2120 // All the chars that differ in capitalization are confusable (above):
2121 let confusable = found
2123 .zip(suggested.chars())
2124 .filter(|(f, s)| f != s)
2125 .all(|(f, s)| (ascii_confusables.contains(&f) || ascii_confusables.contains(&s)));
2126 confusable && found.to_lowercase() == suggested.to_lowercase()
2127 // FIXME: We sometimes suggest the same thing we already have, which is a
2128 // bug, but be defensive against that here.
2129 && found != suggested