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 macro_backtrace: bool,
59 let (short, color_config) = self.unzip();
60 let color = color_config.suggests_using_colors();
61 EmitterWriter::new(dst, source_map, short, teach, color, terminal_width, macro_backtrace)
65 #[derive(Clone, Copy, Debug)]
67 /// The available whitespace in the left that can be consumed when centering.
68 pub whitespace_left: usize,
69 /// The column of the beginning of left-most span.
71 /// The column of the end of right-most span.
72 pub span_right: usize,
73 /// The beginning of the line to be displayed.
74 pub computed_left: usize,
75 /// The end of the line to be displayed.
76 pub computed_right: usize,
77 /// The current width of the terminal. 140 by default and in tests.
78 pub column_width: usize,
79 /// The end column of a span label, including the span. Doesn't account for labels not in the
80 /// same line as the span.
81 pub label_right: usize,
86 whitespace_left: usize,
93 // The 6 is padding to give a bit of room for `...` when displaying:
98 // 16 | ... fn foo(self) -> Self::Bar {
103 whitespace_left: whitespace_left.saturating_sub(6),
104 span_left: span_left.saturating_sub(6),
105 span_right: span_right + 6,
109 label_right: label_right + 6,
111 m.compute(max_line_len);
115 fn was_cut_left(&self) -> bool {
116 self.computed_left > 0
119 fn was_cut_right(&self, line_len: usize) -> bool {
121 if self.computed_right == self.span_right || self.computed_right == self.label_right {
122 // Account for the "..." padding given above. Otherwise we end up with code lines that
123 // do fit but end in "..." as if they were trimmed.
124 self.computed_right - 6
128 right < line_len && self.computed_left + self.column_width < line_len
131 fn compute(&mut self, max_line_len: usize) {
132 // When there's a lot of whitespace (>20), we want to trim it as it is useless.
133 self.computed_left = if self.whitespace_left > 20 {
134 self.whitespace_left - 16 // We want some padding.
138 // We want to show as much as possible, max_line_len is the right-most boundary for the
140 self.computed_right = max(max_line_len, self.computed_left);
142 if self.computed_right - self.computed_left > self.column_width {
143 // Trimming only whitespace isn't enough, let's get craftier.
144 if self.label_right - self.whitespace_left <= self.column_width {
145 // Attempt to fit the code window only trimming whitespace.
146 self.computed_left = self.whitespace_left;
147 self.computed_right = self.computed_left + self.column_width;
148 } else if self.label_right - self.span_left <= self.column_width {
149 // Attempt to fit the code window considering only the spans and labels.
150 let padding_left = (self.column_width - (self.label_right - self.span_left)) / 2;
151 self.computed_left = self.span_left.saturating_sub(padding_left);
152 self.computed_right = self.computed_left + self.column_width;
153 } else if self.span_right - self.span_left <= self.column_width {
154 // Attempt to fit the code window considering the spans and labels plus padding.
155 let padding_left = (self.column_width - (self.span_right - self.span_left)) / 5 * 2;
156 self.computed_left = self.span_left.saturating_sub(padding_left);
157 self.computed_right = self.computed_left + self.column_width;
159 // Mostly give up but still don't show the full line.
160 self.computed_left = self.span_left;
161 self.computed_right = self.span_right;
166 fn left(&self, line_len: usize) -> usize {
167 min(self.computed_left, line_len)
170 fn right(&self, line_len: usize) -> usize {
171 if line_len.saturating_sub(self.computed_left) <= self.column_width {
174 min(line_len, self.computed_right)
179 const ANONYMIZED_LINE_NUM: &str = "LL";
181 /// Emitter trait for emitting errors.
183 /// Emit a structured diagnostic.
184 fn emit_diagnostic(&mut self, diag: &Diagnostic);
186 /// Emit a notification that an artifact has been output.
187 /// This is currently only supported for the JSON format,
188 /// other formats can, and will, simply ignore it.
189 fn emit_artifact_notification(&mut self, _path: &Path, _artifact_type: &str) {}
191 /// Checks if should show explanations about "rustc --explain"
192 fn should_show_explain(&self) -> bool {
196 fn source_map(&self) -> Option<&Lrc<SourceMap>>;
198 /// Formats the substitutions of the primary_span
200 /// The are a lot of conditions to this method, but in short:
202 /// * If the current `Diagnostic` has only one visible `CodeSuggestion`,
203 /// we format the `help` suggestion depending on the content of the
204 /// substitutions. In that case, we return the modified span only.
206 /// * If the current `Diagnostic` has multiple suggestions,
207 /// we return the original `primary_span` and the original suggestions.
208 fn primary_span_formatted<'a>(
210 diag: &'a Diagnostic,
211 ) -> (MultiSpan, &'a [CodeSuggestion]) {
212 let mut primary_span = diag.span.clone();
213 if let Some((sugg, rest)) = diag.suggestions.split_first() {
214 if rest.is_empty() &&
215 // ^ if there is only one suggestion
216 // don't display multi-suggestions as labels
217 sugg.substitutions.len() == 1 &&
218 // don't display multipart suggestions as labels
219 sugg.substitutions[0].parts.len() == 1 &&
220 // don't display long messages as labels
221 sugg.msg.split_whitespace().count() < 10 &&
222 // don't display multiline suggestions as labels
223 !sugg.substitutions[0].parts[0].snippet.contains('\n') &&
225 // when this style is set we want the suggestion to be a message, not inline
226 SuggestionStyle::HideCodeAlways,
227 // trivial suggestion for tooling's sake, never shown
228 SuggestionStyle::CompletelyHidden,
229 // subtle suggestion, never shown inline
230 SuggestionStyle::ShowAlways,
231 ].contains(&sugg.style)
233 let substitution = &sugg.substitutions[0].parts[0].snippet.trim();
234 let msg = if substitution.len() == 0 || sugg.style.hide_inline() {
235 // This substitution is only removal OR we explicitly don't want to show the
236 // code inline (`hide_inline`). Therefore, we don't show the substitution.
237 format!("help: {}", sugg.msg)
239 // Show the default suggestion text with the substitution
245 .map(|sm| is_case_difference(
248 sugg.substitutions[0].parts[0].span,
252 " (notice the capitalization)"
259 primary_span.push_span_label(sugg.substitutions[0].parts[0].span, msg);
261 // We return only the modified primary_span
264 // if there are multiple suggestions, print them all in full
265 // to be consistent. We could try to figure out if we can
266 // make one (or the first one) inline, but that would give
267 // undue importance to a semi-random suggestion
268 (primary_span, &diag.suggestions)
271 (primary_span, &diag.suggestions)
275 fn render_multispans_macro_backtrace_and_fix_extern_macros(
277 source_map: &Option<Lrc<SourceMap>>,
278 span: &mut MultiSpan,
279 children: &mut Vec<SubDiagnostic>,
283 self.render_multispans_macro_backtrace(source_map, span, children, backtrace);
286 if self.fix_multispans_in_extern_macros(source_map, span, children) {
287 let msg = if level == &Error {
288 "this error originates in a macro outside of the current crate \
289 (in Nightly builds, run with -Z macro-backtrace \
293 "this warning originates in a macro outside of the current crate \
294 (in Nightly builds, run with -Z macro-backtrace \
299 children.push(SubDiagnostic {
301 message: vec![(msg, Style::NoStyle)],
302 span: MultiSpan::new(),
309 fn render_multispans_macro_backtrace(
311 source_map: &Option<Lrc<SourceMap>>,
312 span: &mut MultiSpan,
313 children: &mut Vec<SubDiagnostic>,
316 self.render_multispan_macro_backtrace(source_map, span, backtrace);
317 for child in children.iter_mut() {
318 self.render_multispan_macro_backtrace(source_map, &mut child.span, backtrace);
322 fn render_multispan_macro_backtrace(
324 source_map: &Option<Lrc<SourceMap>>,
325 span: &mut MultiSpan,
326 always_backtrace: bool,
328 let sm = match source_map {
333 let mut new_labels: Vec<(Span, String)> = vec![];
335 // First, find all the spans in <*macros> and point instead at their use site
336 for &sp in span.primary_spans() {
340 let macro_backtrace: Vec<_> = sp.macro_backtrace().collect();
341 for (i, trace) in macro_backtrace.iter().rev().enumerate() {
342 // Only show macro locations that are local
343 // and display them like a span_note
344 if trace.def_site.is_dummy() {
347 if always_backtrace {
351 "in this expansion of `{}`{}",
353 if macro_backtrace.len() > 2 {
354 // if macro_backtrace.len() == 1 it'll be
355 // pointed at by "in this macro invocation"
356 format!(" (#{})", i + 1)
363 // Check to make sure we're not in any <*macros>
364 if !sm.span_to_filename(trace.def_site).is_macros()
365 && matches!(trace.kind, ExpnKind::Macro(MacroKind::Bang, _))
371 "in this macro invocation{}",
372 if macro_backtrace.len() > 2 && always_backtrace {
373 // only specify order when the macro
374 // backtrace is multiple levels deep
375 format!(" (#{})", i + 1)
381 if !always_backtrace {
387 for (label_span, label_text) in new_labels {
388 span.push_span_label(label_span, label_text);
392 // This does a small "fix" for multispans by looking to see if it can find any that
393 // point directly at <*macros>. Since these are often difficult to read, this
394 // will change the span to point at the use site.
395 fn fix_multispans_in_extern_macros(
397 source_map: &Option<Lrc<SourceMap>>,
398 span: &mut MultiSpan,
399 children: &mut Vec<SubDiagnostic>,
401 let mut spans_updated = self.fix_multispan_in_extern_macros(source_map, span);
402 for child in children.iter_mut() {
403 spans_updated |= self.fix_multispan_in_extern_macros(source_map, &mut child.span);
408 // This "fixes" MultiSpans that contain Spans that are pointing to locations inside of
409 // <*macros>. Since these locations are often difficult to read, we move these Spans from
410 // <*macros> to their corresponding use site.
411 fn fix_multispan_in_extern_macros(
413 source_map: &Option<Lrc<SourceMap>>,
414 span: &mut MultiSpan,
416 let sm = match source_map {
418 None => return false,
421 // First, find all the spans in <*macros> and point instead at their use site
422 let replacements: Vec<(Span, Span)> = span
426 .chain(span.span_labels().iter().map(|sp_label| sp_label.span))
428 if !sp.is_dummy() && sm.span_to_filename(sp).is_macros() {
429 let maybe_callsite = sp.source_callsite();
430 if sp != maybe_callsite {
431 return Some((sp, maybe_callsite));
438 // After we have them, make sure we replace these 'bad' def sites with their use sites
439 let spans_updated = !replacements.is_empty();
440 for (from, to) in replacements {
441 span.replace(from, to);
448 impl Emitter for EmitterWriter {
449 fn source_map(&self) -> Option<&Lrc<SourceMap>> {
453 fn emit_diagnostic(&mut self, diag: &Diagnostic) {
454 let mut children = diag.children.clone();
455 let (mut primary_span, suggestions) = self.primary_span_formatted(&diag);
457 self.render_multispans_macro_backtrace_and_fix_extern_macros(
462 self.macro_backtrace,
465 self.emit_messages_default(
467 &diag.styled_message(),
475 fn should_show_explain(&self) -> bool {
480 /// An emitter that does nothing when emitting a diagnostic.
481 pub struct SilentEmitter;
483 impl Emitter for SilentEmitter {
484 fn source_map(&self) -> Option<&Lrc<SourceMap>> {
487 fn emit_diagnostic(&mut self, _: &Diagnostic) {}
490 /// Maximum number of lines we will print for each error; arbitrary.
491 pub const MAX_HIGHLIGHT_LINES: usize = 6;
492 /// Maximum number of lines we will print for a multiline suggestion; arbitrary.
494 /// This should be replaced with a more involved mechanism to output multiline suggestions that
495 /// more closely mimmics the regular diagnostic output, where irrelevant code lines are elided.
496 pub const MAX_SUGGESTION_HIGHLIGHT_LINES: usize = 6;
497 /// Maximum number of suggestions to be shown
499 /// Arbitrary, but taken from trait import suggestion limit
500 pub const MAX_SUGGESTIONS: usize = 4;
502 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
503 pub enum ColorConfig {
510 fn to_color_choice(self) -> ColorChoice {
512 ColorConfig::Always => {
513 if atty::is(atty::Stream::Stderr) {
516 ColorChoice::AlwaysAnsi
519 ColorConfig::Never => ColorChoice::Never,
520 ColorConfig::Auto if atty::is(atty::Stream::Stderr) => ColorChoice::Auto,
521 ColorConfig::Auto => ColorChoice::Never,
524 fn suggests_using_colors(self) -> bool {
526 ColorConfig::Always | ColorConfig::Auto => true,
527 ColorConfig::Never => false,
532 /// Handles the writing of `HumanReadableErrorType::Default` and `HumanReadableErrorType::Short`
533 pub struct EmitterWriter {
535 sm: Option<Lrc<SourceMap>>,
539 terminal_width: Option<usize>,
541 macro_backtrace: bool,
545 pub struct FileWithAnnotatedLines {
546 pub file: Lrc<SourceFile>,
547 pub lines: Vec<Line>,
548 multiline_depth: usize,
553 color_config: ColorConfig,
554 source_map: Option<Lrc<SourceMap>>,
557 terminal_width: Option<usize>,
558 macro_backtrace: bool,
560 let dst = Destination::from_stderr(color_config);
573 dst: Box<dyn Write + Send>,
574 source_map: Option<Lrc<SourceMap>>,
578 terminal_width: Option<usize>,
579 macro_backtrace: bool,
582 dst: Raw(dst, colored),
592 pub fn ui_testing(mut self, ui_testing: bool) -> Self {
593 self.ui_testing = ui_testing;
597 fn maybe_anonymized(&self, line_num: usize) -> String {
598 if self.ui_testing { ANONYMIZED_LINE_NUM.to_string() } else { line_num.to_string() }
603 buffer: &mut StyledBuffer,
611 let line_len = source_string.len();
612 // Create the source line we will highlight.
613 let left = margin.left(line_len);
614 let right = margin.right(line_len);
615 // On long lines, we strip the source line, accounting for unicode.
617 let code: String = source_string
621 // Make sure that the trimming on the right will fall within the terminal width.
622 // FIXME: `unicode_width` sometimes disagrees with terminals on how wide a `char` is.
623 // For now, just accept that sometimes the code line will be longer than desired.
624 let next = unicode_width::UnicodeWidthChar::width(*ch).unwrap_or(1);
625 if taken + next > right - left {
632 buffer.puts(line_offset, code_offset, &code, Style::Quotation);
633 if margin.was_cut_left() {
634 // We have stripped some code/whitespace from the beginning, make it clear.
635 buffer.puts(line_offset, code_offset, "...", Style::LineNumber);
637 if margin.was_cut_right(line_len) {
638 // We have stripped some code after the right-most span end, make it clear we did so.
639 buffer.puts(line_offset, code_offset + taken - 3, "...", Style::LineNumber);
641 buffer.puts(line_offset, 0, &self.maybe_anonymized(line_index), Style::LineNumber);
643 draw_col_separator(buffer, line_offset, width_offset - 2);
646 fn render_source_line(
648 buffer: &mut StyledBuffer,
649 file: Lrc<SourceFile>,
654 ) -> Vec<(usize, Style)> {
660 // | secondary span label
662 // ^^ ^ ^^^ ^^^^ ^^^ we don't care about code too far to the right of a span, we trim it
664 // | | | actual code found in your source code and the spans we use to mark it
665 // | | when there's too much wasted space to the left, trim it
666 // | vertical divider between the column number and the code
669 if line.line_index == 0 {
673 let source_string = match file.get_line(line.line_index - 1) {
675 None => return Vec::new(),
678 let line_offset = buffer.num_lines();
680 let left = margin.left(source_string.len()); // Left trim
681 // Account for unicode characters of width !=0 that were removed.
682 let left = source_string
685 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
698 // Special case when there's only one annotation involved, it is the start of a multiline
699 // span and there's no text at the beginning of the code line. Instead of doing the whole
708 // we simplify the output to:
714 if let [ann] = &line.annotations[..] {
715 if let AnnotationType::MultilineStart(depth) = ann.annotation_type {
716 if source_string.chars().take(ann.start_col).all(|c| c.is_whitespace()) {
717 let style = if ann.is_primary {
718 Style::UnderlinePrimary
720 Style::UnderlineSecondary
722 buffer.putc(line_offset, width_offset + depth - 1, '/', style);
723 return vec![(depth, style)];
728 // We want to display like this:
730 // vec.push(vec.pop().unwrap());
731 // --- ^^^ - previous borrow ends here
733 // | error occurs here
734 // previous borrow of `vec` occurs here
736 // But there are some weird edge cases to be aware of:
738 // vec.push(vec.pop().unwrap());
739 // -------- - previous borrow ends here
741 // |this makes no sense
742 // previous borrow of `vec` occurs here
744 // For this reason, we group the lines into "highlight lines"
745 // and "annotations lines", where the highlight lines have the `^`.
747 // Sort the annotations by (start, end col)
748 // The labels are reversed, sort and then reversed again.
749 // Consider a list of annotations (A1, A2, C1, C2, B1, B2) where
750 // the letter signifies the span. Here we are only sorting by the
751 // span and hence, the order of the elements with the same span will
752 // not change. On reversing the ordering (|a, b| but b.cmp(a)), you get
753 // (C1, C2, B1, B2, A1, A2). All the elements with the same span are
754 // still ordered first to last, but all the elements with different
755 // spans are ordered by their spans in last to first order. Last to
756 // first order is important, because the jiggly lines and | are on
757 // the left, so the rightmost span needs to be rendered first,
758 // otherwise the lines would end up needing to go over a message.
760 let mut annotations = line.annotations.clone();
761 annotations.sort_by_key(|a| Reverse(a.start_col));
763 // First, figure out where each label will be positioned.
765 // In the case where you have the following annotations:
767 // vec.push(vec.pop().unwrap());
768 // -------- - previous borrow ends here [C]
770 // |this makes no sense [B]
771 // previous borrow of `vec` occurs here [A]
773 // `annotations_position` will hold [(2, A), (1, B), (0, C)].
775 // We try, when possible, to stick the rightmost annotation at the end
776 // of the highlight line:
778 // vec.push(vec.pop().unwrap());
779 // --- --- - previous borrow ends here
781 // But sometimes that's not possible because one of the other
782 // annotations overlaps it. For example, from the test
783 // `span_overlap_label`, we have the following annotations
784 // (written on distinct lines for clarity):
790 // In this case, we can't stick the rightmost-most label on
791 // the highlight line, or we would get:
798 // which is totally weird. Instead we want:
806 // which is...less weird, at least. In fact, in general, if
807 // the rightmost span overlaps with any other span, we should
808 // use the "hang below" version, so we can at least make it
809 // clear where the span *starts*. There's an exception for this
810 // logic, when the labels do not have a message:
825 let mut annotations_position = vec![];
826 let mut line_len = 0;
828 for (i, annotation) in annotations.iter().enumerate() {
829 for (j, next) in annotations.iter().enumerate() {
830 if overlaps(next, annotation, 0) // This label overlaps with another one and both
831 && annotation.has_label() // take space (they have text and are not
832 && j > i // multiline lines).
834 // We're currently on the first line, move the label one line down
836 // If we're overlapping with an un-labelled annotation with the same span
837 // we can just merge them in the output
838 if next.start_col == annotation.start_col
839 && next.end_col == annotation.end_col
845 // This annotation needs a new line in the output.
850 annotations_position.push((p, annotation));
851 for (j, next) in annotations.iter().enumerate() {
853 let l = next.label.as_ref().map_or(0, |label| label.len() + 2);
854 if (overlaps(next, annotation, l) // Do not allow two labels to be in the same
855 // line if they overlap including padding, to
856 // avoid situations like:
863 && annotation.has_label() // Both labels must have some text, otherwise
864 && next.has_label()) // they are not overlapping.
865 // Do not add a new line if this annotation
866 // or the next are vertical line placeholders.
867 || (annotation.takes_space() // If either this or the next annotation is
868 && next.has_label()) // multiline start/end, move it to a new line
869 || (annotation.has_label() // so as not to overlap the orizontal lines.
870 && next.takes_space())
871 || (annotation.takes_space() && next.takes_space())
872 || (overlaps(next, annotation, l)
873 && next.end_col <= annotation.end_col
878 // This annotation needs a new line in the output.
884 line_len = max(line_len, p);
891 // If there are no annotations or the only annotations on this line are
892 // MultilineLine, then there's only code being shown, stop processing.
893 if line.annotations.iter().all(|a| a.is_line()) {
897 // Write the column separator.
899 // After this we will have:
908 for pos in 0..=line_len {
909 draw_col_separator(buffer, line_offset + pos + 1, width_offset - 2);
910 buffer.putc(line_offset + pos + 1, width_offset - 2, '|', Style::LineNumber);
913 // Write the horizontal lines for multiline annotations
914 // (only the first and last lines need this).
916 // After this we will have:
925 for &(pos, annotation) in &annotations_position {
926 let style = if annotation.is_primary {
927 Style::UnderlinePrimary
929 Style::UnderlineSecondary
932 match annotation.annotation_type {
933 AnnotationType::MultilineStart(depth) | AnnotationType::MultilineEnd(depth) => {
938 width_offset + depth,
939 code_offset + annotation.start_col - left,
944 buffer.set_style_range(
946 code_offset + annotation.start_col - left,
947 code_offset + annotation.end_col - left,
949 annotation.is_primary,
956 // Write the vertical lines for labels that are on a different line as the underline.
958 // After this we will have:
967 for &(pos, annotation) in &annotations_position {
968 let style = if annotation.is_primary {
969 Style::UnderlinePrimary
971 Style::UnderlineSecondary
975 if pos > 1 && (annotation.has_label() || annotation.takes_space()) {
976 for p in line_offset + 1..=line_offset + pos {
979 (code_offset + annotation.start_col).saturating_sub(left),
985 match annotation.annotation_type {
986 AnnotationType::MultilineStart(depth) => {
987 for p in line_offset + pos + 1..line_offset + line_len + 2 {
988 buffer.putc(p, width_offset + depth - 1, '|', style);
991 AnnotationType::MultilineEnd(depth) => {
992 for p in line_offset..=line_offset + pos {
993 buffer.putc(p, width_offset + depth - 1, '|', style);
1000 // Write the labels on the annotations that actually have a label.
1002 // After this we will have:
1007 // | something about `foo`
1011 for &(pos, annotation) in &annotations_position {
1013 if annotation.is_primary { Style::LabelPrimary } else { Style::LabelSecondary };
1014 let (pos, col) = if pos == 0 {
1015 (pos + 1, (annotation.end_col + 1).saturating_sub(left))
1017 (pos + 2, annotation.start_col.saturating_sub(left))
1019 if let Some(ref label) = annotation.label {
1020 buffer.puts(line_offset + pos, code_offset + col, &label, style);
1024 // Sort from biggest span to smallest span so that smaller spans are
1025 // represented in the output:
1030 // | | something about `foo`
1031 // | something about `fn foo()`
1032 annotations_position.sort_by_key(|(_, ann)| {
1033 // Decreasing order. When annotations share the same length, prefer `Primary`.
1034 (Reverse(ann.len()), ann.is_primary)
1037 // Write the underlines.
1039 // After this we will have:
1044 // | something about `foo`
1048 for &(_, annotation) in &annotations_position {
1049 let (underline, style) = if annotation.is_primary {
1050 ('^', Style::UnderlinePrimary)
1052 ('-', Style::UnderlineSecondary)
1054 for p in annotation.start_col..annotation.end_col {
1057 (code_offset + p).saturating_sub(left),
1063 annotations_position
1065 .filter_map(|&(_, annotation)| match annotation.annotation_type {
1066 AnnotationType::MultilineStart(p) | AnnotationType::MultilineEnd(p) => {
1067 let style = if annotation.is_primary {
1070 Style::LabelSecondary
1076 .collect::<Vec<_>>()
1079 fn get_multispan_max_line_num(&mut self, msp: &MultiSpan) -> usize {
1080 let sm = match self.sm {
1086 for primary_span in msp.primary_spans() {
1087 if !primary_span.is_dummy() {
1088 let hi = sm.lookup_char_pos(primary_span.hi());
1089 max = (hi.line).max(max);
1092 if !self.short_message {
1093 for span_label in msp.span_labels() {
1094 if !span_label.span.is_dummy() {
1095 let hi = sm.lookup_char_pos(span_label.span.hi());
1096 max = (hi.line).max(max);
1104 fn get_max_line_num(&mut self, span: &MultiSpan, children: &[SubDiagnostic]) -> usize {
1105 let primary = self.get_multispan_max_line_num(span);
1108 .map(|sub| self.get_multispan_max_line_num(&sub.span))
1114 /// Adds a left margin to every line but the first, given a padding length and the label being
1115 /// displayed, keeping the provided highlighting.
1118 buffer: &mut StyledBuffer,
1119 msg: &[(String, Style)],
1122 override_style: Option<Style>,
1124 // The extra 5 ` ` is padding that's always needed to align to the `note: `:
1127 // --> file.rs:13:20
1132 // = note: multiline
1137 // | | length of label
1139 // `max_line_num_len`
1140 let padding = " ".repeat(padding + label.len() + 5);
1142 /// Returns `override` if it is present and `style` is `NoStyle` or `style` otherwise
1143 fn style_or_override(style: Style, override_: Option<Style>) -> Style {
1144 match (style, override_) {
1145 (Style::NoStyle, Some(override_)) => override_,
1150 let mut line_number = 0;
1152 // Provided the following diagnostic message:
1156 // ("highlighted multiline\nstring to\nsee how it ", Style::NoStyle),
1157 // ("looks", Style::Highlight),
1158 // ("with\nvery ", Style::NoStyle),
1159 // ("weird", Style::Highlight),
1160 // (" formats\n", Style::NoStyle),
1161 // ("see?", Style::Highlight),
1164 // the expected output on a note is (* surround the highlighted text)
1166 // = note: highlighted multiline
1168 // see how it *looks* with
1169 // very *weird* formats
1171 for &(ref text, ref style) in msg.iter() {
1172 let lines = text.split('\n').collect::<Vec<_>>();
1173 if lines.len() > 1 {
1174 for (i, line) in lines.iter().enumerate() {
1177 buffer.append(line_number, &padding, Style::NoStyle);
1179 buffer.append(line_number, line, style_or_override(*style, override_style));
1182 buffer.append(line_number, text, style_or_override(*style, override_style));
1187 fn emit_message_default(
1190 msg: &[(String, Style)],
1191 code: &Option<DiagnosticId>,
1193 max_line_num_len: usize,
1195 ) -> io::Result<()> {
1196 let mut buffer = StyledBuffer::new();
1197 let header_style = if is_secondary { Style::HeaderMsg } else { Style::MainHeaderMsg };
1199 if !msp.has_primary_spans() && !msp.has_span_labels() && is_secondary && !self.short_message
1201 // This is a secondary message with no span info
1202 for _ in 0..max_line_num_len {
1203 buffer.prepend(0, " ", Style::NoStyle);
1205 draw_note_separator(&mut buffer, 0, max_line_num_len + 1);
1206 if *level != Level::FailureNote {
1207 let level_str = level.to_string();
1208 if !level_str.is_empty() {
1209 buffer.append(0, &level_str, Style::MainHeaderMsg);
1210 buffer.append(0, ": ", Style::NoStyle);
1213 self.msg_to_buffer(&mut buffer, msg, max_line_num_len, "note", None);
1215 let level_str = level.to_string();
1216 // The failure note level itself does not provide any useful diagnostic information
1217 if *level != Level::FailureNote && !level_str.is_empty() {
1218 buffer.append(0, &level_str, Style::Level(*level));
1220 // only render error codes, not lint codes
1221 if let Some(DiagnosticId::Error(ref code)) = *code {
1222 buffer.append(0, "[", Style::Level(*level));
1223 buffer.append(0, &code, Style::Level(*level));
1224 buffer.append(0, "]", Style::Level(*level));
1226 if *level != Level::FailureNote && !level_str.is_empty() {
1227 buffer.append(0, ": ", header_style);
1229 for &(ref text, _) in msg.iter() {
1230 buffer.append(0, text, header_style);
1234 let mut annotated_files = FileWithAnnotatedLines::collect_annotations(msp, &self.sm);
1236 // Make sure our primary file comes first
1237 let (primary_lo, sm) = if let (Some(sm), Some(ref primary_span)) =
1238 (self.sm.as_ref(), msp.primary_span().as_ref())
1240 if !primary_span.is_dummy() {
1241 (sm.lookup_char_pos(primary_span.lo()), sm)
1243 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1247 // If we don't have span information, emit and exit
1248 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1252 annotated_files.binary_search_by(|x| x.file.name.cmp(&primary_lo.file.name))
1254 annotated_files.swap(0, pos);
1257 // Print out the annotate source lines that correspond with the error
1258 for annotated_file in annotated_files {
1259 // we can't annotate anything if the source is unavailable.
1260 if !sm.ensure_source_file_source_present(annotated_file.file.clone()) {
1264 // print out the span location and spacer before we print the annotated source
1265 // to do this, we need to know if this span will be primary
1266 let is_primary = primary_lo.file.name == annotated_file.file.name;
1268 let loc = primary_lo.clone();
1269 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();
1273 buffer.prepend(buffer_msg_line_offset, "--> ", Style::LineNumber);
1275 buffer_msg_line_offset,
1279 sm.doctest_offset_line(&loc.file.name, loc.line),
1282 Style::LineAndColumn,
1284 for _ in 0..max_line_num_len {
1285 buffer.prepend(buffer_msg_line_offset, " ", Style::NoStyle);
1293 sm.doctest_offset_line(&loc.file.name, loc.line),
1296 Style::LineAndColumn,
1299 } else if !self.short_message {
1300 // remember where we are in the output buffer for easy reference
1301 let buffer_msg_line_offset = buffer.num_lines();
1304 draw_col_separator(&mut buffer, buffer_msg_line_offset, max_line_num_len + 1);
1306 // Then, the secondary file indicator
1307 buffer.prepend(buffer_msg_line_offset + 1, "::: ", Style::LineNumber);
1308 let loc = if let Some(first_line) = annotated_file.lines.first() {
1309 let col = if let Some(first_annotation) = first_line.annotations.first() {
1310 format!(":{}", first_annotation.start_col + 1)
1316 annotated_file.file.name,
1317 sm.doctest_offset_line(&annotated_file.file.name, first_line.line_index),
1321 annotated_file.file.name.to_string()
1323 buffer.append(buffer_msg_line_offset + 1, &loc, Style::LineAndColumn);
1324 for _ in 0..max_line_num_len {
1325 buffer.prepend(buffer_msg_line_offset + 1, " ", Style::NoStyle);
1329 if !self.short_message {
1330 // Put in the spacer between the location and annotated source
1331 let buffer_msg_line_offset = buffer.num_lines();
1332 draw_col_separator_no_space(
1334 buffer_msg_line_offset,
1335 max_line_num_len + 1,
1338 // Contains the vertical lines' positions for active multiline annotations
1339 let mut multilines = FxHashMap::default();
1341 // Get the left-side margin to remove it
1342 let mut whitespace_margin = std::usize::MAX;
1343 for line_idx in 0..annotated_file.lines.len() {
1344 let file = annotated_file.file.clone();
1345 let line = &annotated_file.lines[line_idx];
1346 if let Some(source_string) = file.get_line(line.line_index - 1) {
1347 let leading_whitespace =
1348 source_string.chars().take_while(|c| c.is_whitespace()).count();
1349 if source_string.chars().any(|c| !c.is_whitespace()) {
1350 whitespace_margin = min(whitespace_margin, leading_whitespace);
1354 if whitespace_margin == std::usize::MAX {
1355 whitespace_margin = 0;
1358 // Left-most column any visible span points at.
1359 let mut span_left_margin = std::usize::MAX;
1360 for line in &annotated_file.lines {
1361 for ann in &line.annotations {
1362 span_left_margin = min(span_left_margin, ann.start_col);
1363 span_left_margin = min(span_left_margin, ann.end_col);
1366 if span_left_margin == std::usize::MAX {
1367 span_left_margin = 0;
1370 // Right-most column any visible span points at.
1371 let mut span_right_margin = 0;
1372 let mut label_right_margin = 0;
1373 let mut max_line_len = 0;
1374 for line in &annotated_file.lines {
1377 annotated_file.file.get_line(line.line_index - 1).map_or(0, |s| s.len()),
1379 for ann in &line.annotations {
1380 span_right_margin = max(span_right_margin, ann.start_col);
1381 span_right_margin = max(span_right_margin, ann.end_col);
1382 // FIXME: account for labels not in the same line
1383 let label_right = ann.label.as_ref().map_or(0, |l| l.len() + 1);
1384 label_right_margin = max(label_right_margin, ann.end_col + label_right);
1388 let width_offset = 3 + max_line_num_len;
1389 let code_offset = if annotated_file.multiline_depth == 0 {
1392 width_offset + annotated_file.multiline_depth + 1
1395 let column_width = if let Some(width) = self.terminal_width {
1396 width.saturating_sub(code_offset)
1397 } else if self.ui_testing {
1400 termize::dimensions()
1401 .map(|(w, _)| w.saturating_sub(code_offset))
1402 .unwrap_or(std::usize::MAX)
1405 let margin = Margin::new(
1414 // Next, output the annotate source for this file
1415 for line_idx in 0..annotated_file.lines.len() {
1416 let previous_buffer_line = buffer.num_lines();
1418 let depths = self.render_source_line(
1420 annotated_file.file.clone(),
1421 &annotated_file.lines[line_idx],
1427 let mut to_add = FxHashMap::default();
1429 for (depth, style) in depths {
1430 if multilines.get(&depth).is_some() {
1431 multilines.remove(&depth);
1433 to_add.insert(depth, style);
1437 // Set the multiline annotation vertical lines to the left of
1438 // the code in this line.
1439 for (depth, style) in &multilines {
1440 for line in previous_buffer_line..buffer.num_lines() {
1441 draw_multiline_line(&mut buffer, line, width_offset, *depth, *style);
1444 // check to see if we need to print out or elide lines that come between
1445 // this annotated line and the next one.
1446 if line_idx < (annotated_file.lines.len() - 1) {
1447 let line_idx_delta = annotated_file.lines[line_idx + 1].line_index
1448 - annotated_file.lines[line_idx].line_index;
1449 if line_idx_delta > 2 {
1450 let last_buffer_line_num = buffer.num_lines();
1451 buffer.puts(last_buffer_line_num, 0, "...", Style::LineNumber);
1453 // Set the multiline annotation vertical lines on `...` bridging line.
1454 for (depth, style) in &multilines {
1455 draw_multiline_line(
1457 last_buffer_line_num,
1463 } else if line_idx_delta == 2 {
1464 let unannotated_line = annotated_file
1466 .get_line(annotated_file.lines[line_idx].line_index)
1467 .unwrap_or_else(|| Cow::from(""));
1469 let last_buffer_line_num = buffer.num_lines();
1474 annotated_file.lines[line_idx + 1].line_index - 1,
1475 last_buffer_line_num,
1481 for (depth, style) in &multilines {
1482 draw_multiline_line(
1484 last_buffer_line_num,
1493 multilines.extend(&to_add);
1498 // final step: take our styled buffer, render it, then output it
1499 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1504 fn emit_suggestion_default(
1506 suggestion: &CodeSuggestion,
1508 max_line_num_len: usize,
1509 ) -> io::Result<()> {
1510 let sm = match self.sm {
1512 None => return Ok(()),
1515 // Render the replacements for each suggestion
1516 let suggestions = suggestion.splice_lines(&**sm);
1518 if suggestions.is_empty() {
1519 // Suggestions coming from macros can have malformed spans. This is a heavy handed
1520 // approach to avoid ICEs by ignoring the suggestion outright.
1524 let mut buffer = StyledBuffer::new();
1526 // Render the suggestion message
1527 let level_str = level.to_string();
1528 if !level_str.is_empty() {
1529 buffer.append(0, &level_str, Style::Level(*level));
1530 buffer.append(0, ": ", Style::HeaderMsg);
1534 &[(suggestion.msg.to_owned(), Style::NoStyle)],
1537 Some(Style::HeaderMsg),
1540 let mut row_num = 2;
1541 let mut notice_capitalization = false;
1542 for (complete, parts, only_capitalization) in suggestions.iter().take(MAX_SUGGESTIONS) {
1543 notice_capitalization |= only_capitalization;
1544 // Only show underline if the suggestion spans a single line and doesn't cover the
1545 // entirety of the code output. If you have multiple replacements in the same line
1546 // of code, show the underline.
1547 let show_underline = !(parts.len() == 1 && parts[0].snippet.trim() == complete.trim())
1548 && complete.lines().count() == 1;
1551 .span_to_lines(parts[0].span)
1552 .expect("span_to_lines failed when emitting suggestion");
1554 assert!(!lines.lines.is_empty());
1556 let line_start = sm.lookup_char_pos(parts[0].span.lo()).line;
1557 draw_col_separator_no_space(&mut buffer, 1, max_line_num_len + 1);
1558 let mut line_pos = 0;
1559 let mut lines = complete.lines();
1560 for line in lines.by_ref().take(MAX_SUGGESTION_HIGHLIGHT_LINES) {
1561 // Print the span column to avoid confusion
1565 &self.maybe_anonymized(line_start + line_pos),
1568 // print the suggestion
1569 draw_col_separator(&mut buffer, row_num, max_line_num_len + 1);
1570 buffer.append(row_num, line, Style::NoStyle);
1575 // This offset and the ones below need to be signed to account for replacement code
1576 // that is shorter than the original code.
1577 let mut offsets: Vec<(usize, isize)> = Vec::new();
1578 // Only show an underline in the suggestions if the suggestion is not the
1579 // entirety of the code being shown and the displayed code is not multiline.
1581 draw_col_separator(&mut buffer, row_num, max_line_num_len + 1);
1583 let span_start_pos = sm.lookup_char_pos(part.span.lo()).col_display;
1584 let span_end_pos = sm.lookup_char_pos(part.span.hi()).col_display;
1586 // Do not underline the leading...
1587 let start = part.snippet.len().saturating_sub(part.snippet.trim_start().len());
1588 // ...or trailing spaces. Account for substitutions containing unicode
1590 let sub_len: usize = part
1594 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
1597 let offset: isize = offsets
1600 |(start, v)| if span_start_pos <= *start { None } else { Some(v) },
1603 let underline_start = (span_start_pos + start) as isize + offset;
1604 let underline_end = (span_start_pos + start + sub_len) as isize + offset;
1605 assert!(underline_start >= 0 && underline_end >= 0);
1606 for p in underline_start..underline_end {
1609 ((max_line_num_len + 3) as isize + p) as usize,
1611 Style::UnderlinePrimary,
1614 // underline removals too
1615 if underline_start == underline_end {
1616 for p in underline_start - 1..underline_start + 1 {
1619 ((max_line_num_len + 3) as isize + p) as usize,
1621 Style::UnderlineSecondary,
1626 // length of the code after substitution
1627 let full_sub_len = part
1630 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
1631 .sum::<usize>() as isize;
1633 // length of the code to be substituted
1634 let snippet_len = span_end_pos as isize - span_start_pos as isize;
1635 // For multiple substitutions, use the position *after* the previous
1636 // substitutions have happened, only when further substitutions are
1637 // located strictly after.
1638 offsets.push((span_end_pos, full_sub_len - snippet_len));
1643 // if we elided some lines, add an ellipsis
1644 if lines.next().is_some() {
1645 buffer.puts(row_num, max_line_num_len - 1, "...", Style::LineNumber);
1646 } else if !show_underline {
1647 draw_col_separator_no_space(&mut buffer, row_num, max_line_num_len + 1);
1651 if suggestions.len() > MAX_SUGGESTIONS {
1652 let others = suggestions.len() - MAX_SUGGESTIONS;
1653 let msg = format!("and {} other candidate{}", others, pluralize!(others));
1654 buffer.puts(row_num, max_line_num_len + 3, &msg, Style::NoStyle);
1655 } else if notice_capitalization {
1656 let msg = "notice the capitalization difference";
1657 buffer.puts(row_num, max_line_num_len + 3, &msg, Style::NoStyle);
1659 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1663 fn emit_messages_default(
1666 message: &[(String, Style)],
1667 code: &Option<DiagnosticId>,
1669 children: &[SubDiagnostic],
1670 suggestions: &[CodeSuggestion],
1672 let max_line_num_len = if self.ui_testing {
1673 ANONYMIZED_LINE_NUM.len()
1675 self.get_max_line_num(span, children).to_string().len()
1678 match self.emit_message_default(span, message, code, level, max_line_num_len, false) {
1680 if !children.is_empty()
1681 || suggestions.iter().any(|s| s.style != SuggestionStyle::CompletelyHidden)
1683 let mut buffer = StyledBuffer::new();
1684 if !self.short_message {
1685 draw_col_separator_no_space(&mut buffer, 0, max_line_num_len + 1);
1687 match emit_to_destination(
1694 Err(e) => panic!("failed to emit error: {}", e),
1697 if !self.short_message {
1698 for child in children {
1699 let span = child.render_span.as_ref().unwrap_or(&child.span);
1700 match self.emit_message_default(
1702 &child.styled_message(),
1708 Err(e) => panic!("failed to emit error: {}", e),
1712 for sugg in suggestions {
1713 if sugg.style == SuggestionStyle::CompletelyHidden {
1714 // do not display this suggestion, it is meant only for tools
1715 } else if sugg.style == SuggestionStyle::HideCodeAlways {
1716 match self.emit_message_default(
1718 &[(sugg.msg.to_owned(), Style::HeaderMsg)],
1724 Err(e) => panic!("failed to emit error: {}", e),
1728 match self.emit_suggestion_default(sugg, &Level::Help, max_line_num_len)
1730 Err(e) => panic!("failed to emit error: {}", e),
1737 Err(e) => panic!("failed to emit error: {}", e),
1740 let mut dst = self.dst.writable();
1741 match writeln!(dst) {
1742 Err(e) => panic!("failed to emit error: {}", e),
1743 _ => match dst.flush() {
1744 Err(e) => panic!("failed to emit error: {}", e),
1751 impl FileWithAnnotatedLines {
1752 /// Preprocess all the annotations so that they are grouped by file and by line number
1753 /// This helps us quickly iterate over the whole message (including secondary file spans)
1754 pub fn collect_annotations(
1756 source_map: &Option<Lrc<SourceMap>>,
1757 ) -> Vec<FileWithAnnotatedLines> {
1758 fn add_annotation_to_file(
1759 file_vec: &mut Vec<FileWithAnnotatedLines>,
1760 file: Lrc<SourceFile>,
1764 for slot in file_vec.iter_mut() {
1765 // Look through each of our files for the one we're adding to
1766 if slot.file.name == file.name {
1767 // See if we already have a line for it
1768 for line_slot in &mut slot.lines {
1769 if line_slot.line_index == line_index {
1770 line_slot.annotations.push(ann);
1774 // We don't have a line yet, create one
1775 slot.lines.push(Line { line_index, annotations: vec![ann] });
1780 // This is the first time we're seeing the file
1781 file_vec.push(FileWithAnnotatedLines {
1783 lines: vec![Line { line_index, annotations: vec![ann] }],
1788 let mut output = vec![];
1789 let mut multiline_annotations = vec![];
1791 if let Some(ref sm) = source_map {
1792 for span_label in msp.span_labels() {
1793 if span_label.span.is_dummy() {
1797 let lo = sm.lookup_char_pos(span_label.span.lo());
1798 let mut hi = sm.lookup_char_pos(span_label.span.hi());
1800 // Watch out for "empty spans". If we get a span like 6..6, we
1801 // want to just display a `^` at 6, so convert that to
1802 // 6..7. This is degenerate input, but it's best to degrade
1803 // gracefully -- and the parser likes to supply a span like
1804 // that for EOF, in particular.
1806 if lo.col_display == hi.col_display && lo.line == hi.line {
1807 hi.col_display += 1;
1810 if lo.line != hi.line {
1811 let ml = MultilineAnnotation {
1813 line_start: lo.line,
1815 start_col: lo.col_display,
1816 end_col: hi.col_display,
1817 is_primary: span_label.is_primary,
1818 label: span_label.label,
1819 overlaps_exactly: false,
1821 multiline_annotations.push((lo.file, ml));
1823 let ann = Annotation {
1824 start_col: lo.col_display,
1825 end_col: hi.col_display,
1826 is_primary: span_label.is_primary,
1827 label: span_label.label,
1828 annotation_type: AnnotationType::Singleline,
1830 add_annotation_to_file(&mut output, lo.file, lo.line, ann);
1835 // Find overlapping multiline annotations, put them at different depths
1836 multiline_annotations.sort_by_key(|&(_, ref ml)| (ml.line_start, ml.line_end));
1837 for (_, ann) in multiline_annotations.clone() {
1838 for (_, a) in multiline_annotations.iter_mut() {
1839 // Move all other multiline annotations overlapping with this one
1840 // one level to the right.
1841 if !(ann.same_span(a))
1842 && num_overlap(ann.line_start, ann.line_end, a.line_start, a.line_end, true)
1845 } else if ann.same_span(a) && &ann != a {
1846 a.overlaps_exactly = true;
1853 let mut max_depth = 0; // max overlapping multiline spans
1854 for (file, ann) in multiline_annotations {
1855 max_depth = max(max_depth, ann.depth);
1856 let mut end_ann = ann.as_end();
1857 if !ann.overlaps_exactly {
1858 // avoid output like
1880 add_annotation_to_file(&mut output, file.clone(), ann.line_start, ann.as_start());
1881 // 4 is the minimum vertical length of a multiline span when presented: two lines
1882 // of code and two lines of underline. This is not true for the special case where
1883 // the beginning doesn't have an underline, but the current logic seems to be
1884 // working correctly.
1885 let middle = min(ann.line_start + 4, ann.line_end);
1886 for line in ann.line_start + 1..middle {
1887 // Every `|` that joins the beginning of the span (`___^`) to the end (`|__^`).
1888 add_annotation_to_file(&mut output, file.clone(), line, ann.as_line());
1890 let line_end = ann.line_end - 1;
1891 if middle < line_end {
1892 add_annotation_to_file(&mut output, file.clone(), line_end, ann.as_line());
1895 end_ann.annotation_type = AnnotationType::Singleline;
1897 add_annotation_to_file(&mut output, file, ann.line_end, end_ann);
1899 for file_vec in output.iter_mut() {
1900 file_vec.multiline_depth = max_depth;
1906 fn draw_col_separator(buffer: &mut StyledBuffer, line: usize, col: usize) {
1907 buffer.puts(line, col, "| ", Style::LineNumber);
1910 fn draw_col_separator_no_space(buffer: &mut StyledBuffer, line: usize, col: usize) {
1911 draw_col_separator_no_space_with_style(buffer, line, col, Style::LineNumber);
1914 fn draw_col_separator_no_space_with_style(
1915 buffer: &mut StyledBuffer,
1920 buffer.putc(line, col, '|', style);
1924 buffer: &mut StyledBuffer,
1931 for col in col_from..col_to {
1932 buffer.putc(line, col, symbol, style);
1936 fn draw_note_separator(buffer: &mut StyledBuffer, line: usize, col: usize) {
1937 buffer.puts(line, col, "= ", Style::LineNumber);
1940 fn draw_multiline_line(
1941 buffer: &mut StyledBuffer,
1947 buffer.putc(line, offset + depth - 1, '|', style);
1957 let extra = if inclusive { 1 } else { 0 };
1958 (b_start..b_end + extra).contains(&a_start) || (a_start..a_end + extra).contains(&b_start)
1960 fn overlaps(a1: &Annotation, a2: &Annotation, padding: usize) -> bool {
1961 num_overlap(a1.start_col, a1.end_col + padding, a2.start_col, a2.end_col, false)
1964 fn emit_to_destination(
1965 rendered_buffer: &[Vec<StyledString>],
1967 dst: &mut Destination,
1968 short_message: bool,
1969 ) -> io::Result<()> {
1972 let mut dst = dst.writable();
1974 // In order to prevent error message interleaving, where multiple error lines get intermixed
1975 // when multiple compiler processes error simultaneously, we emit errors with additional
1978 // On Unix systems, we write into a buffered terminal rather than directly to a terminal. When
1979 // the .flush() is called we take the buffer created from the buffered writes and write it at
1980 // one shot. Because the Unix systems use ANSI for the colors, which is a text-based styling
1981 // scheme, this buffered approach works and maintains the styling.
1983 // On Windows, styling happens through calls to a terminal API. This prevents us from using the
1984 // same buffering approach. Instead, we use a global Windows mutex, which we acquire long
1985 // enough to output the full error message, then we release.
1986 let _buffer_lock = lock::acquire_global_lock("rustc_errors");
1987 for (pos, line) in rendered_buffer.iter().enumerate() {
1989 dst.apply_style(lvl.clone(), part.style)?;
1990 write!(dst, "{}", part.text)?;
1993 if !short_message && (!lvl.is_failure_note() || pos != rendered_buffer.len() - 1) {
2001 pub enum Destination {
2002 Terminal(StandardStream),
2003 Buffered(BufferWriter),
2004 // The bool denotes whether we should be emitting ansi color codes or not
2005 Raw(Box<(dyn Write + Send)>, bool),
2008 pub enum WritableDst<'a> {
2009 Terminal(&'a mut StandardStream),
2010 Buffered(&'a mut BufferWriter, Buffer),
2011 Raw(&'a mut (dyn Write + Send)),
2012 ColoredRaw(Ansi<&'a mut (dyn Write + Send)>),
2016 fn from_stderr(color: ColorConfig) -> Destination {
2017 let choice = color.to_color_choice();
2018 // On Windows we'll be performing global synchronization on the entire
2019 // system for emitting rustc errors, so there's no need to buffer
2022 // On non-Windows we rely on the atomicity of `write` to ensure errors
2023 // don't get all jumbled up.
2025 Terminal(StandardStream::stderr(choice))
2027 Buffered(BufferWriter::stderr(choice))
2031 fn writable(&mut self) -> WritableDst<'_> {
2033 Destination::Terminal(ref mut t) => WritableDst::Terminal(t),
2034 Destination::Buffered(ref mut t) => {
2035 let buf = t.buffer();
2036 WritableDst::Buffered(t, buf)
2038 Destination::Raw(ref mut t, false) => WritableDst::Raw(t),
2039 Destination::Raw(ref mut t, true) => WritableDst::ColoredRaw(Ansi::new(t)),
2044 impl<'a> WritableDst<'a> {
2045 fn apply_style(&mut self, lvl: Level, style: Style) -> io::Result<()> {
2046 let mut spec = ColorSpec::new();
2048 Style::LineAndColumn => {}
2049 Style::LineNumber => {
2050 spec.set_bold(true);
2051 spec.set_intense(true);
2053 spec.set_fg(Some(Color::Cyan));
2055 spec.set_fg(Some(Color::Blue));
2058 Style::Quotation => {}
2059 Style::MainHeaderMsg => {
2060 spec.set_bold(true);
2062 spec.set_intense(true).set_fg(Some(Color::White));
2065 Style::UnderlinePrimary | Style::LabelPrimary => {
2067 spec.set_bold(true);
2069 Style::UnderlineSecondary | Style::LabelSecondary => {
2070 spec.set_bold(true).set_intense(true);
2072 spec.set_fg(Some(Color::Cyan));
2074 spec.set_fg(Some(Color::Blue));
2077 Style::HeaderMsg | Style::NoStyle => {}
2078 Style::Level(lvl) => {
2080 spec.set_bold(true);
2082 Style::Highlight => {
2083 spec.set_bold(true);
2086 self.set_color(&spec)
2089 fn set_color(&mut self, color: &ColorSpec) -> io::Result<()> {
2091 WritableDst::Terminal(ref mut t) => t.set_color(color),
2092 WritableDst::Buffered(_, ref mut t) => t.set_color(color),
2093 WritableDst::ColoredRaw(ref mut t) => t.set_color(color),
2094 WritableDst::Raw(_) => Ok(()),
2098 fn reset(&mut self) -> io::Result<()> {
2100 WritableDst::Terminal(ref mut t) => t.reset(),
2101 WritableDst::Buffered(_, ref mut t) => t.reset(),
2102 WritableDst::ColoredRaw(ref mut t) => t.reset(),
2103 WritableDst::Raw(_) => Ok(()),
2108 impl<'a> Write for WritableDst<'a> {
2109 fn write(&mut self, bytes: &[u8]) -> io::Result<usize> {
2111 WritableDst::Terminal(ref mut t) => t.write(bytes),
2112 WritableDst::Buffered(_, ref mut buf) => buf.write(bytes),
2113 WritableDst::Raw(ref mut w) => w.write(bytes),
2114 WritableDst::ColoredRaw(ref mut t) => t.write(bytes),
2118 fn flush(&mut self) -> io::Result<()> {
2120 WritableDst::Terminal(ref mut t) => t.flush(),
2121 WritableDst::Buffered(_, ref mut buf) => buf.flush(),
2122 WritableDst::Raw(ref mut w) => w.flush(),
2123 WritableDst::ColoredRaw(ref mut w) => w.flush(),
2128 impl<'a> Drop for WritableDst<'a> {
2129 fn drop(&mut self) {
2131 WritableDst::Buffered(ref mut dst, ref mut buf) => {
2132 drop(dst.print(buf));
2139 /// Whether the original and suggested code are visually similar enough to warrant extra wording.
2140 pub fn is_case_difference(sm: &SourceMap, suggested: &str, sp: Span) -> bool {
2141 // FIXME: this should probably be extended to also account for `FO0` → `FOO` and unicode.
2142 let found = match sm.span_to_snippet(sp) {
2143 Ok(snippet) => snippet,
2145 warn!("Invalid span {:?}. Err={:?}", sp, e);
2149 let ascii_confusables = &['c', 'f', 'i', 'k', 'o', 's', 'u', 'v', 'w', 'x', 'y', 'z'];
2150 // All the chars that differ in capitalization are confusable (above):
2151 let confusable = found
2153 .zip(suggested.chars())
2154 .filter(|(f, s)| f != s)
2155 .all(|(f, s)| (ascii_confusables.contains(&f) || ascii_confusables.contains(&s)));
2156 confusable && found.to_lowercase() == suggested.to_lowercase()
2157 // FIXME: We sometimes suggest the same thing we already have, which is a
2158 // bug, but be defensive against that here.
2159 && found != suggested