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 `rustc_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;
18 CodeSuggestion, Diagnostic, DiagnosticId, Handler, Level, SubDiagnostic, SubstitutionHighlight,
22 use rustc_lint_defs::pluralize;
24 use rustc_data_structures::fx::FxHashMap;
25 use rustc_data_structures::sync::Lrc;
26 use rustc_span::hygiene::{ExpnKind, MacroKind};
28 use std::cmp::{max, min, Reverse};
30 use std::io::prelude::*;
33 use termcolor::{Ansi, BufferWriter, ColorChoice, ColorSpec, StandardStream};
34 use termcolor::{Buffer, Color, WriteColor};
37 /// Default column width, used in tests and when terminal dimensions cannot be determined.
38 const DEFAULT_COLUMN_WIDTH: usize = 140;
40 /// Describes the way the content of the `rendered` field of the json output is generated
41 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
42 pub enum HumanReadableErrorType {
44 AnnotateSnippet(ColorConfig),
48 impl HumanReadableErrorType {
49 /// Returns a (`short`, `color`) tuple
50 pub fn unzip(self) -> (bool, ColorConfig) {
52 HumanReadableErrorType::Default(cc) => (false, cc),
53 HumanReadableErrorType::Short(cc) => (true, cc),
54 HumanReadableErrorType::AnnotateSnippet(cc) => (false, cc),
59 dst: Box<dyn Write + Send>,
60 source_map: Option<Lrc<SourceMap>>,
62 terminal_width: Option<usize>,
63 macro_backtrace: bool,
65 let (short, color_config) = self.unzip();
66 let color = color_config.suggests_using_colors();
67 EmitterWriter::new(dst, source_map, short, teach, color, terminal_width, macro_backtrace)
71 #[derive(Clone, Copy, Debug)]
73 /// The available whitespace in the left that can be consumed when centering.
74 pub whitespace_left: usize,
75 /// The column of the beginning of left-most span.
77 /// The column of the end of right-most span.
78 pub span_right: usize,
79 /// The beginning of the line to be displayed.
80 pub computed_left: usize,
81 /// The end of the line to be displayed.
82 pub computed_right: usize,
83 /// The current width of the terminal. Uses value of `DEFAULT_COLUMN_WIDTH` constant by default
85 pub column_width: usize,
86 /// The end column of a span label, including the span. Doesn't account for labels not in the
87 /// same line as the span.
88 pub label_right: usize,
93 whitespace_left: usize,
100 // The 6 is padding to give a bit of room for `...` when displaying:
105 // 16 | ... fn foo(self) -> Self::Bar {
110 whitespace_left: whitespace_left.saturating_sub(6),
111 span_left: span_left.saturating_sub(6),
112 span_right: span_right + 6,
116 label_right: label_right + 6,
118 m.compute(max_line_len);
122 fn was_cut_left(&self) -> bool {
123 self.computed_left > 0
126 fn was_cut_right(&self, line_len: usize) -> bool {
128 if self.computed_right == self.span_right || self.computed_right == self.label_right {
129 // Account for the "..." padding given above. Otherwise we end up with code lines that
130 // do fit but end in "..." as if they were trimmed.
131 self.computed_right - 6
135 right < line_len && self.computed_left + self.column_width < line_len
138 fn compute(&mut self, max_line_len: usize) {
139 // When there's a lot of whitespace (>20), we want to trim it as it is useless.
140 self.computed_left = if self.whitespace_left > 20 {
141 self.whitespace_left - 16 // We want some padding.
145 // We want to show as much as possible, max_line_len is the right-most boundary for the
147 self.computed_right = max(max_line_len, self.computed_left);
149 if self.computed_right - self.computed_left > self.column_width {
150 // Trimming only whitespace isn't enough, let's get craftier.
151 if self.label_right - self.whitespace_left <= self.column_width {
152 // Attempt to fit the code window only trimming whitespace.
153 self.computed_left = self.whitespace_left;
154 self.computed_right = self.computed_left + self.column_width;
155 } else if self.label_right - self.span_left <= self.column_width {
156 // Attempt to fit the code window considering only the spans and labels.
157 let padding_left = (self.column_width - (self.label_right - self.span_left)) / 2;
158 self.computed_left = self.span_left.saturating_sub(padding_left);
159 self.computed_right = self.computed_left + self.column_width;
160 } else if self.span_right - self.span_left <= self.column_width {
161 // Attempt to fit the code window considering the spans and labels plus padding.
162 let padding_left = (self.column_width - (self.span_right - self.span_left)) / 5 * 2;
163 self.computed_left = self.span_left.saturating_sub(padding_left);
164 self.computed_right = self.computed_left + self.column_width;
166 // Mostly give up but still don't show the full line.
167 self.computed_left = self.span_left;
168 self.computed_right = self.span_right;
173 fn left(&self, line_len: usize) -> usize {
174 min(self.computed_left, line_len)
177 fn right(&self, line_len: usize) -> usize {
178 if line_len.saturating_sub(self.computed_left) <= self.column_width {
181 min(line_len, self.computed_right)
186 const ANONYMIZED_LINE_NUM: &str = "LL";
188 /// Emitter trait for emitting errors.
190 /// Emit a structured diagnostic.
191 fn emit_diagnostic(&mut self, diag: &Diagnostic);
193 /// Emit a notification that an artifact has been output.
194 /// This is currently only supported for the JSON format,
195 /// other formats can, and will, simply ignore it.
196 fn emit_artifact_notification(&mut self, _path: &Path, _artifact_type: &str) {}
198 fn emit_future_breakage_report(&mut self, _diags: Vec<Diagnostic>) {}
200 /// Emit list of unused externs
201 fn emit_unused_externs(&mut self, _lint_level: &str, _unused_externs: &[&str]) {}
203 /// Checks if should show explanations about "rustc --explain"
204 fn should_show_explain(&self) -> bool {
208 /// Checks if we can use colors in the current output stream.
209 fn supports_color(&self) -> bool {
213 fn source_map(&self) -> Option<&Lrc<SourceMap>>;
215 /// Formats the substitutions of the primary_span
217 /// The are a lot of conditions to this method, but in short:
219 /// * If the current `Diagnostic` has only one visible `CodeSuggestion`,
220 /// we format the `help` suggestion depending on the content of the
221 /// substitutions. In that case, we return the modified span only.
223 /// * If the current `Diagnostic` has multiple suggestions,
224 /// we return the original `primary_span` and the original suggestions.
225 fn primary_span_formatted<'a>(
227 diag: &'a Diagnostic,
228 ) -> (MultiSpan, &'a [CodeSuggestion]) {
229 let mut primary_span = diag.span.clone();
230 if let Some((sugg, rest)) = diag.suggestions.split_first() {
231 if rest.is_empty() &&
232 // ^ if there is only one suggestion
233 // don't display multi-suggestions as labels
234 sugg.substitutions.len() == 1 &&
235 // don't display multipart suggestions as labels
236 sugg.substitutions[0].parts.len() == 1 &&
237 // don't display long messages as labels
238 sugg.msg.split_whitespace().count() < 10 &&
239 // don't display multiline suggestions as labels
240 !sugg.substitutions[0].parts[0].snippet.contains('\n') &&
242 // when this style is set we want the suggestion to be a message, not inline
243 SuggestionStyle::HideCodeAlways,
244 // trivial suggestion for tooling's sake, never shown
245 SuggestionStyle::CompletelyHidden,
246 // subtle suggestion, never shown inline
247 SuggestionStyle::ShowAlways,
248 ].contains(&sugg.style)
250 let substitution = &sugg.substitutions[0].parts[0].snippet.trim();
251 let msg = if substitution.is_empty() || sugg.style.hide_inline() {
252 // This substitution is only removal OR we explicitly don't want to show the
253 // code inline (`hide_inline`). Therefore, we don't show the substitution.
254 format!("help: {}", sugg.msg)
256 // Show the default suggestion text with the substitution
262 .map(|sm| is_case_difference(
265 sugg.substitutions[0].parts[0].span,
269 " (notice the capitalization)"
276 primary_span.push_span_label(sugg.substitutions[0].parts[0].span, msg);
278 // We return only the modified primary_span
281 // if there are multiple suggestions, print them all in full
282 // to be consistent. We could try to figure out if we can
283 // make one (or the first one) inline, but that would give
284 // undue importance to a semi-random suggestion
285 (primary_span, &diag.suggestions)
288 (primary_span, &diag.suggestions)
292 fn fix_multispans_in_extern_macros_and_render_macro_backtrace(
294 source_map: &Option<Lrc<SourceMap>>,
295 span: &mut MultiSpan,
296 children: &mut Vec<SubDiagnostic>,
300 // Check for spans in macros, before `fix_multispans_in_extern_macros`
301 // has a chance to replace them.
302 let has_macro_spans = iter::once(&*span)
303 .chain(children.iter().map(|child| &child.span))
304 .flat_map(|span| span.primary_spans())
305 .flat_map(|sp| sp.macro_backtrace())
306 .find_map(|expn_data| {
307 match expn_data.kind {
308 ExpnKind::Root => None,
310 // Skip past non-macro entries, just in case there
311 // are some which do actually involve macros.
312 ExpnKind::Inlined | ExpnKind::Desugaring(..) | ExpnKind::AstPass(..) => None,
314 ExpnKind::Macro(macro_kind, name) => Some((macro_kind, name)),
319 self.fix_multispans_in_extern_macros(source_map, span, children);
322 self.render_multispans_macro_backtrace(span, children, backtrace);
325 if let Some((macro_kind, name)) = has_macro_spans {
326 let descr = macro_kind.descr();
329 "this {level} originates in the {descr} `{name}` \
330 (in Nightly builds, run with -Z macro-backtrace for more info)",
333 children.push(SubDiagnostic {
335 message: vec![(msg, Style::NoStyle)],
336 span: MultiSpan::new(),
343 fn render_multispans_macro_backtrace(
345 span: &mut MultiSpan,
346 children: &mut Vec<SubDiagnostic>,
349 for span in iter::once(span).chain(children.iter_mut().map(|child| &mut child.span)) {
350 self.render_multispan_macro_backtrace(span, backtrace);
354 fn render_multispan_macro_backtrace(&self, span: &mut MultiSpan, always_backtrace: bool) {
355 let mut new_labels: Vec<(Span, String)> = vec![];
357 for &sp in span.primary_spans() {
362 // FIXME(eddyb) use `retain` on `macro_backtrace` to remove all the
363 // entries we don't want to print, to make sure the indices being
364 // printed are contiguous (or omitted if there's only one entry).
365 let macro_backtrace: Vec<_> = sp.macro_backtrace().collect();
366 for (i, trace) in macro_backtrace.iter().rev().enumerate() {
367 if trace.def_site.is_dummy() {
371 if always_backtrace && !matches!(trace.kind, ExpnKind::Inlined) {
375 "in this expansion of `{}`{}",
377 if macro_backtrace.len() > 1 {
378 // if macro_backtrace.len() == 1 it'll be
379 // pointed at by "in this macro invocation"
380 format!(" (#{})", i + 1)
388 // Don't add a label on the call site if the diagnostic itself
389 // already points to (a part of) that call site, as the label
390 // is meant for showing the relevant invocation when the actual
391 // diagnostic is pointing to some part of macro definition.
393 // This also handles the case where an external span got replaced
394 // with the call site span by `fix_multispans_in_extern_macros`.
396 // NB: `-Zmacro-backtrace` overrides this, for uniformity, as the
397 // "in this expansion of" label above is always added in that mode,
398 // and it needs an "in this macro invocation" label to match that.
399 let redundant_span = trace.call_site.contains(sp);
401 if !redundant_span || always_backtrace {
402 let msg: Cow<'static, _> = match trace.kind {
403 ExpnKind::Macro(MacroKind::Attr, _) => {
404 "this procedural macro expansion".into()
406 ExpnKind::Macro(MacroKind::Derive, _) => {
407 "this derive macro expansion".into()
409 ExpnKind::Macro(MacroKind::Bang, _) => "this macro invocation".into(),
410 ExpnKind::Inlined => "the inlined copy of this code".into(),
411 ExpnKind::Root => "in the crate root".into(),
412 ExpnKind::AstPass(kind) => kind.descr().into(),
413 ExpnKind::Desugaring(kind) => {
414 format!("this {} desugaring", kind.descr()).into()
422 if macro_backtrace.len() > 1 && always_backtrace {
423 // only specify order when the macro
424 // backtrace is multiple levels deep
425 format!(" (#{})", i + 1)
432 if !always_backtrace {
438 for (label_span, label_text) in new_labels {
439 span.push_span_label(label_span, label_text);
443 // This does a small "fix" for multispans by looking to see if it can find any that
444 // point directly at external macros. Since these are often difficult to read,
445 // this will change the span to point at the use site.
446 fn fix_multispans_in_extern_macros(
448 source_map: &Option<Lrc<SourceMap>>,
449 span: &mut MultiSpan,
450 children: &mut Vec<SubDiagnostic>,
452 let Some(source_map) = source_map else { return };
453 debug!("fix_multispans_in_extern_macros: before: span={:?} children={:?}", span, children);
454 self.fix_multispan_in_extern_macros(source_map, span);
455 for child in children.iter_mut() {
456 self.fix_multispan_in_extern_macros(source_map, &mut child.span);
458 debug!("fix_multispans_in_extern_macros: after: span={:?} children={:?}", span, children);
461 // This "fixes" MultiSpans that contain `Span`s pointing to locations inside of external macros.
462 // Since these locations are often difficult to read,
463 // we move these spans from the external macros to their corresponding use site.
464 fn fix_multispan_in_extern_macros(&self, source_map: &Lrc<SourceMap>, span: &mut MultiSpan) {
465 // First, find all the spans in external macros and point instead at their use site.
466 let replacements: Vec<(Span, Span)> = span
470 .chain(span.span_labels().iter().map(|sp_label| sp_label.span))
472 if !sp.is_dummy() && source_map.is_imported(sp) {
473 let maybe_callsite = sp.source_callsite();
474 if sp != maybe_callsite {
475 return Some((sp, maybe_callsite));
482 // After we have them, make sure we replace these 'bad' def sites with their use sites.
483 for (from, to) in replacements {
484 span.replace(from, to);
489 impl Emitter for EmitterWriter {
490 fn source_map(&self) -> Option<&Lrc<SourceMap>> {
494 fn emit_diagnostic(&mut self, diag: &Diagnostic) {
495 let mut children = diag.children.clone();
496 let (mut primary_span, suggestions) = self.primary_span_formatted(&diag);
497 debug!("emit_diagnostic: suggestions={:?}", suggestions);
499 self.fix_multispans_in_extern_macros_and_render_macro_backtrace(
504 self.macro_backtrace,
507 self.emit_messages_default(
509 &diag.styled_message(),
517 fn should_show_explain(&self) -> bool {
521 fn supports_color(&self) -> bool {
522 self.dst.supports_color()
526 /// An emitter that does nothing when emitting a non-fatal diagnostic.
527 /// Fatal diagnostics are forwarded to `fatal_handler` to avoid silent
528 /// failures of rustc, as witnessed e.g. in issue #89358.
529 pub struct SilentEmitter {
530 pub fatal_handler: Handler,
531 pub fatal_note: Option<String>,
534 impl Emitter for SilentEmitter {
535 fn source_map(&self) -> Option<&Lrc<SourceMap>> {
538 fn emit_diagnostic(&mut self, d: &Diagnostic) {
539 if d.level == Level::Fatal {
540 let mut d = d.clone();
541 if let Some(ref note) = self.fatal_note {
544 self.fatal_handler.emit_diagnostic(&d);
549 /// Maximum number of lines we will print for a multiline suggestion; arbitrary.
551 /// This should be replaced with a more involved mechanism to output multiline suggestions that
552 /// more closely mimics the regular diagnostic output, where irrelevant code lines are elided.
553 pub const MAX_SUGGESTION_HIGHLIGHT_LINES: usize = 6;
554 /// Maximum number of suggestions to be shown
556 /// Arbitrary, but taken from trait import suggestion limit
557 pub const MAX_SUGGESTIONS: usize = 4;
559 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
560 pub enum ColorConfig {
567 fn to_color_choice(self) -> ColorChoice {
569 ColorConfig::Always => {
570 if atty::is(atty::Stream::Stderr) {
573 ColorChoice::AlwaysAnsi
576 ColorConfig::Never => ColorChoice::Never,
577 ColorConfig::Auto if atty::is(atty::Stream::Stderr) => ColorChoice::Auto,
578 ColorConfig::Auto => ColorChoice::Never,
581 fn suggests_using_colors(self) -> bool {
583 ColorConfig::Always | ColorConfig::Auto => true,
584 ColorConfig::Never => false,
589 /// Handles the writing of `HumanReadableErrorType::Default` and `HumanReadableErrorType::Short`
590 pub struct EmitterWriter {
592 sm: Option<Lrc<SourceMap>>,
596 terminal_width: Option<usize>,
598 macro_backtrace: bool,
602 pub struct FileWithAnnotatedLines {
603 pub file: Lrc<SourceFile>,
604 pub lines: Vec<Line>,
605 multiline_depth: usize,
610 color_config: ColorConfig,
611 source_map: Option<Lrc<SourceMap>>,
614 terminal_width: Option<usize>,
615 macro_backtrace: bool,
617 let dst = Destination::from_stderr(color_config);
630 dst: Box<dyn Write + Send>,
631 source_map: Option<Lrc<SourceMap>>,
635 terminal_width: Option<usize>,
636 macro_backtrace: bool,
639 dst: Raw(dst, colored),
649 pub fn ui_testing(mut self, ui_testing: bool) -> Self {
650 self.ui_testing = ui_testing;
654 fn maybe_anonymized(&self, line_num: usize) -> String {
655 if self.ui_testing { ANONYMIZED_LINE_NUM.to_string() } else { line_num.to_string() }
660 buffer: &mut StyledBuffer,
668 // Tabs are assumed to have been replaced by spaces in calling code.
669 debug_assert!(!source_string.contains('\t'));
670 let line_len = source_string.len();
671 // Create the source line we will highlight.
672 let left = margin.left(line_len);
673 let right = margin.right(line_len);
674 // On long lines, we strip the source line, accounting for unicode.
676 let code: String = source_string
680 // Make sure that the trimming on the right will fall within the terminal width.
681 // FIXME: `unicode_width` sometimes disagrees with terminals on how wide a `char` is.
682 // For now, just accept that sometimes the code line will be longer than desired.
683 let next = unicode_width::UnicodeWidthChar::width(*ch).unwrap_or(1);
684 if taken + next > right - left {
691 buffer.puts(line_offset, code_offset, &code, Style::Quotation);
692 if margin.was_cut_left() {
693 // We have stripped some code/whitespace from the beginning, make it clear.
694 buffer.puts(line_offset, code_offset, "...", Style::LineNumber);
696 if margin.was_cut_right(line_len) {
697 // We have stripped some code after the right-most span end, make it clear we did so.
698 buffer.puts(line_offset, code_offset + taken - 3, "...", Style::LineNumber);
700 buffer.puts(line_offset, 0, &self.maybe_anonymized(line_index), Style::LineNumber);
702 draw_col_separator(buffer, line_offset, width_offset - 2);
705 fn render_source_line(
707 buffer: &mut StyledBuffer,
708 file: Lrc<SourceFile>,
713 ) -> Vec<(usize, Style)> {
719 // | secondary span label
721 // ^^ ^ ^^^ ^^^^ ^^^ we don't care about code too far to the right of a span, we trim it
723 // | | | actual code found in your source code and the spans we use to mark it
724 // | | when there's too much wasted space to the left, trim it
725 // | vertical divider between the column number and the code
728 if line.line_index == 0 {
732 let source_string = match file.get_line(line.line_index - 1) {
733 Some(s) => normalize_whitespace(&*s),
734 None => return Vec::new(),
737 let line_offset = buffer.num_lines();
739 let left = margin.left(source_string.len()); // Left trim
740 // Account for unicode characters of width !=0 that were removed.
741 let left = source_string
744 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
757 // Special case when there's only one annotation involved, it is the start of a multiline
758 // span and there's no text at the beginning of the code line. Instead of doing the whole
767 // we simplify the output to:
773 if let [ann] = &line.annotations[..] {
774 if let AnnotationType::MultilineStart(depth) = ann.annotation_type {
775 if source_string.chars().take(ann.start_col).all(|c| c.is_whitespace()) {
776 let style = if ann.is_primary {
777 Style::UnderlinePrimary
779 Style::UnderlineSecondary
781 buffer.putc(line_offset, width_offset + depth - 1, '/', style);
782 return vec![(depth, style)];
787 // We want to display like this:
789 // vec.push(vec.pop().unwrap());
790 // --- ^^^ - previous borrow ends here
792 // | error occurs here
793 // previous borrow of `vec` occurs here
795 // But there are some weird edge cases to be aware of:
797 // vec.push(vec.pop().unwrap());
798 // -------- - previous borrow ends here
800 // |this makes no sense
801 // previous borrow of `vec` occurs here
803 // For this reason, we group the lines into "highlight lines"
804 // and "annotations lines", where the highlight lines have the `^`.
806 // Sort the annotations by (start, end col)
807 // The labels are reversed, sort and then reversed again.
808 // Consider a list of annotations (A1, A2, C1, C2, B1, B2) where
809 // the letter signifies the span. Here we are only sorting by the
810 // span and hence, the order of the elements with the same span will
811 // not change. On reversing the ordering (|a, b| but b.cmp(a)), you get
812 // (C1, C2, B1, B2, A1, A2). All the elements with the same span are
813 // still ordered first to last, but all the elements with different
814 // spans are ordered by their spans in last to first order. Last to
815 // first order is important, because the jiggly lines and | are on
816 // the left, so the rightmost span needs to be rendered first,
817 // otherwise the lines would end up needing to go over a message.
819 let mut annotations = line.annotations.clone();
820 annotations.sort_by_key(|a| Reverse(a.start_col));
822 // First, figure out where each label will be positioned.
824 // In the case where you have the following annotations:
826 // vec.push(vec.pop().unwrap());
827 // -------- - previous borrow ends here [C]
829 // |this makes no sense [B]
830 // previous borrow of `vec` occurs here [A]
832 // `annotations_position` will hold [(2, A), (1, B), (0, C)].
834 // We try, when possible, to stick the rightmost annotation at the end
835 // of the highlight line:
837 // vec.push(vec.pop().unwrap());
838 // --- --- - previous borrow ends here
840 // But sometimes that's not possible because one of the other
841 // annotations overlaps it. For example, from the test
842 // `span_overlap_label`, we have the following annotations
843 // (written on distinct lines for clarity):
849 // In this case, we can't stick the rightmost-most label on
850 // the highlight line, or we would get:
857 // which is totally weird. Instead we want:
865 // which is...less weird, at least. In fact, in general, if
866 // the rightmost span overlaps with any other span, we should
867 // use the "hang below" version, so we can at least make it
868 // clear where the span *starts*. There's an exception for this
869 // logic, when the labels do not have a message:
884 let mut annotations_position = vec![];
885 let mut line_len = 0;
887 for (i, annotation) in annotations.iter().enumerate() {
888 for (j, next) in annotations.iter().enumerate() {
889 if overlaps(next, annotation, 0) // This label overlaps with another one and both
890 && annotation.has_label() // take space (they have text and are not
891 && j > i // multiline lines).
893 // We're currently on the first line, move the label one line down
895 // If we're overlapping with an un-labelled annotation with the same span
896 // we can just merge them in the output
897 if next.start_col == annotation.start_col
898 && next.end_col == annotation.end_col
904 // This annotation needs a new line in the output.
909 annotations_position.push((p, annotation));
910 for (j, next) in annotations.iter().enumerate() {
912 let l = next.label.as_ref().map_or(0, |label| label.len() + 2);
913 if (overlaps(next, annotation, l) // Do not allow two labels to be in the same
914 // line if they overlap including padding, to
915 // avoid situations like:
922 && annotation.has_label() // Both labels must have some text, otherwise
923 && next.has_label()) // they are not overlapping.
924 // Do not add a new line if this annotation
925 // or the next are vertical line placeholders.
926 || (annotation.takes_space() // If either this or the next annotation is
927 && next.has_label()) // multiline start/end, move it to a new line
928 || (annotation.has_label() // so as not to overlap the horizontal lines.
929 && next.takes_space())
930 || (annotation.takes_space() && next.takes_space())
931 || (overlaps(next, annotation, l)
932 && next.end_col <= annotation.end_col
937 // This annotation needs a new line in the output.
943 line_len = max(line_len, p);
950 // If there are no annotations or the only annotations on this line are
951 // MultilineLine, then there's only code being shown, stop processing.
952 if line.annotations.iter().all(|a| a.is_line()) {
956 // Write the column separator.
958 // After this we will have:
967 for pos in 0..=line_len {
968 draw_col_separator(buffer, line_offset + pos + 1, width_offset - 2);
971 // Write the horizontal lines for multiline annotations
972 // (only the first and last lines need this).
974 // After this we will have:
983 for &(pos, annotation) in &annotations_position {
984 let style = if annotation.is_primary {
985 Style::UnderlinePrimary
987 Style::UnderlineSecondary
990 match annotation.annotation_type {
991 AnnotationType::MultilineStart(depth) | AnnotationType::MultilineEnd(depth) => {
996 width_offset + depth,
997 (code_offset + annotation.start_col).saturating_sub(left),
1001 _ if self.teach => {
1002 buffer.set_style_range(
1004 (code_offset + annotation.start_col).saturating_sub(left),
1005 (code_offset + annotation.end_col).saturating_sub(left),
1007 annotation.is_primary,
1014 // Write the vertical lines for labels that are on a different line as the underline.
1016 // After this we will have:
1025 for &(pos, annotation) in &annotations_position {
1026 let style = if annotation.is_primary {
1027 Style::UnderlinePrimary
1029 Style::UnderlineSecondary
1033 if pos > 1 && (annotation.has_label() || annotation.takes_space()) {
1034 for p in line_offset + 1..=line_offset + pos {
1037 (code_offset + annotation.start_col).saturating_sub(left),
1043 match annotation.annotation_type {
1044 AnnotationType::MultilineStart(depth) => {
1045 for p in line_offset + pos + 1..line_offset + line_len + 2 {
1046 buffer.putc(p, width_offset + depth - 1, '|', style);
1049 AnnotationType::MultilineEnd(depth) => {
1050 for p in line_offset..=line_offset + pos {
1051 buffer.putc(p, width_offset + depth - 1, '|', style);
1058 // Write the labels on the annotations that actually have a label.
1060 // After this we will have:
1065 // | something about `foo`
1069 for &(pos, annotation) in &annotations_position {
1071 if annotation.is_primary { Style::LabelPrimary } else { Style::LabelSecondary };
1072 let (pos, col) = if pos == 0 {
1073 (pos + 1, (annotation.end_col + 1).saturating_sub(left))
1075 (pos + 2, annotation.start_col.saturating_sub(left))
1077 if let Some(ref label) = annotation.label {
1078 buffer.puts(line_offset + pos, code_offset + col, &label, style);
1082 // Sort from biggest span to smallest span so that smaller spans are
1083 // represented in the output:
1088 // | | something about `foo`
1089 // | something about `fn foo()`
1090 annotations_position.sort_by_key(|(_, ann)| {
1091 // Decreasing order. When annotations share the same length, prefer `Primary`.
1092 (Reverse(ann.len()), ann.is_primary)
1095 // Write the underlines.
1097 // After this we will have:
1102 // | something about `foo`
1106 for &(_, annotation) in &annotations_position {
1107 let (underline, style) = if annotation.is_primary {
1108 ('^', Style::UnderlinePrimary)
1110 ('-', Style::UnderlineSecondary)
1112 for p in annotation.start_col..annotation.end_col {
1115 (code_offset + p).saturating_sub(left),
1121 annotations_position
1123 .filter_map(|&(_, annotation)| match annotation.annotation_type {
1124 AnnotationType::MultilineStart(p) | AnnotationType::MultilineEnd(p) => {
1125 let style = if annotation.is_primary {
1128 Style::LabelSecondary
1134 .collect::<Vec<_>>()
1137 fn get_multispan_max_line_num(&mut self, msp: &MultiSpan) -> usize {
1138 let sm = match self.sm {
1144 for primary_span in msp.primary_spans() {
1145 if !primary_span.is_dummy() {
1146 let hi = sm.lookup_char_pos(primary_span.hi());
1147 max = (hi.line).max(max);
1150 if !self.short_message {
1151 for span_label in msp.span_labels() {
1152 if !span_label.span.is_dummy() {
1153 let hi = sm.lookup_char_pos(span_label.span.hi());
1154 max = (hi.line).max(max);
1162 fn get_max_line_num(&mut self, span: &MultiSpan, children: &[SubDiagnostic]) -> usize {
1163 let primary = self.get_multispan_max_line_num(span);
1166 .map(|sub| self.get_multispan_max_line_num(&sub.span))
1172 /// Adds a left margin to every line but the first, given a padding length and the label being
1173 /// displayed, keeping the provided highlighting.
1176 buffer: &mut StyledBuffer,
1177 msg: &[(String, Style)],
1180 override_style: Option<Style>,
1182 // The extra 5 ` ` is padding that's always needed to align to the `note: `:
1185 // --> file.rs:13:20
1190 // = note: multiline
1195 // | | length of label
1197 // `max_line_num_len`
1198 let padding = " ".repeat(padding + label.len() + 5);
1200 /// Returns `override` if it is present and `style` is `NoStyle` or `style` otherwise
1201 fn style_or_override(style: Style, override_: Option<Style>) -> Style {
1202 match (style, override_) {
1203 (Style::NoStyle, Some(override_)) => override_,
1208 let mut line_number = 0;
1210 // Provided the following diagnostic message:
1214 // ("highlighted multiline\nstring to\nsee how it ", Style::NoStyle),
1215 // ("looks", Style::Highlight),
1216 // ("with\nvery ", Style::NoStyle),
1217 // ("weird", Style::Highlight),
1218 // (" formats\n", Style::NoStyle),
1219 // ("see?", Style::Highlight),
1222 // the expected output on a note is (* surround the highlighted text)
1224 // = note: highlighted multiline
1226 // see how it *looks* with
1227 // very *weird* formats
1229 for &(ref text, ref style) in msg.iter() {
1230 let lines = text.split('\n').collect::<Vec<_>>();
1231 if lines.len() > 1 {
1232 for (i, line) in lines.iter().enumerate() {
1235 buffer.append(line_number, &padding, Style::NoStyle);
1237 buffer.append(line_number, line, style_or_override(*style, override_style));
1240 buffer.append(line_number, text, style_or_override(*style, override_style));
1245 fn emit_message_default(
1248 msg: &[(String, Style)],
1249 code: &Option<DiagnosticId>,
1251 max_line_num_len: usize,
1253 ) -> io::Result<()> {
1254 let mut buffer = StyledBuffer::new();
1256 if !msp.has_primary_spans() && !msp.has_span_labels() && is_secondary && !self.short_message
1258 // This is a secondary message with no span info
1259 for _ in 0..max_line_num_len {
1260 buffer.prepend(0, " ", Style::NoStyle);
1262 draw_note_separator(&mut buffer, 0, max_line_num_len + 1);
1263 if *level != Level::FailureNote {
1264 buffer.append(0, level.to_str(), Style::MainHeaderMsg);
1265 buffer.append(0, ": ", Style::NoStyle);
1267 self.msg_to_buffer(&mut buffer, msg, max_line_num_len, "note", None);
1269 let mut label_width = 0;
1270 // The failure note level itself does not provide any useful diagnostic information
1271 if *level != Level::FailureNote {
1272 buffer.append(0, level.to_str(), Style::Level(*level));
1273 label_width += level.to_str().len();
1275 // only render error codes, not lint codes
1276 if let Some(DiagnosticId::Error(ref code)) = *code {
1277 buffer.append(0, "[", Style::Level(*level));
1278 buffer.append(0, &code, Style::Level(*level));
1279 buffer.append(0, "]", Style::Level(*level));
1280 label_width += 2 + code.len();
1282 let header_style = if is_secondary { Style::HeaderMsg } else { Style::MainHeaderMsg };
1283 if *level != Level::FailureNote {
1284 buffer.append(0, ": ", header_style);
1287 for &(ref text, _) in msg.iter() {
1288 // Account for newlines to align output to its label.
1289 for (line, text) in normalize_whitespace(text).lines().enumerate() {
1294 if line == 0 { String::new() } else { " ".repeat(label_width) },
1303 let mut annotated_files = FileWithAnnotatedLines::collect_annotations(msp, &self.sm);
1305 // Make sure our primary file comes first
1306 let (primary_lo, sm) = if let (Some(sm), Some(ref primary_span)) =
1307 (self.sm.as_ref(), msp.primary_span().as_ref())
1309 if !primary_span.is_dummy() {
1310 (sm.lookup_char_pos(primary_span.lo()), sm)
1312 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1316 // If we don't have span information, emit and exit
1317 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1321 annotated_files.binary_search_by(|x| x.file.name.cmp(&primary_lo.file.name))
1323 annotated_files.swap(0, pos);
1326 // Print out the annotate source lines that correspond with the error
1327 for annotated_file in annotated_files {
1328 // we can't annotate anything if the source is unavailable.
1329 if !sm.ensure_source_file_source_present(annotated_file.file.clone()) {
1333 // print out the span location and spacer before we print the annotated source
1334 // to do this, we need to know if this span will be primary
1335 let is_primary = primary_lo.file.name == annotated_file.file.name;
1337 let loc = primary_lo.clone();
1338 if !self.short_message {
1339 // remember where we are in the output buffer for easy reference
1340 let buffer_msg_line_offset = buffer.num_lines();
1342 buffer.prepend(buffer_msg_line_offset, "--> ", Style::LineNumber);
1344 buffer_msg_line_offset,
1347 sm.filename_for_diagnostics(&loc.file.name),
1348 sm.doctest_offset_line(&loc.file.name, loc.line),
1351 Style::LineAndColumn,
1353 for _ in 0..max_line_num_len {
1354 buffer.prepend(buffer_msg_line_offset, " ", Style::NoStyle);
1361 sm.filename_for_diagnostics(&loc.file.name),
1362 sm.doctest_offset_line(&loc.file.name, loc.line),
1365 Style::LineAndColumn,
1368 } else if !self.short_message {
1369 // remember where we are in the output buffer for easy reference
1370 let buffer_msg_line_offset = buffer.num_lines();
1373 draw_col_separator_no_space(
1375 buffer_msg_line_offset,
1376 max_line_num_len + 1,
1379 // Then, the secondary file indicator
1380 buffer.prepend(buffer_msg_line_offset + 1, "::: ", Style::LineNumber);
1381 let loc = if let Some(first_line) = annotated_file.lines.first() {
1382 let col = if let Some(first_annotation) = first_line.annotations.first() {
1383 format!(":{}", first_annotation.start_col + 1)
1389 sm.filename_for_diagnostics(&annotated_file.file.name),
1390 sm.doctest_offset_line(&annotated_file.file.name, first_line.line_index),
1394 format!("{}", sm.filename_for_diagnostics(&annotated_file.file.name))
1396 buffer.append(buffer_msg_line_offset + 1, &loc, Style::LineAndColumn);
1397 for _ in 0..max_line_num_len {
1398 buffer.prepend(buffer_msg_line_offset + 1, " ", Style::NoStyle);
1402 if !self.short_message {
1403 // Put in the spacer between the location and annotated source
1404 let buffer_msg_line_offset = buffer.num_lines();
1405 draw_col_separator_no_space(
1407 buffer_msg_line_offset,
1408 max_line_num_len + 1,
1411 // Contains the vertical lines' positions for active multiline annotations
1412 let mut multilines = FxHashMap::default();
1414 // Get the left-side margin to remove it
1415 let mut whitespace_margin = usize::MAX;
1416 for line_idx in 0..annotated_file.lines.len() {
1417 let file = annotated_file.file.clone();
1418 let line = &annotated_file.lines[line_idx];
1419 if let Some(source_string) = file.get_line(line.line_index - 1) {
1420 let leading_whitespace = source_string
1422 .take_while(|c| c.is_whitespace())
1425 // Tabs are displayed as 4 spaces
1431 if source_string.chars().any(|c| !c.is_whitespace()) {
1432 whitespace_margin = min(whitespace_margin, leading_whitespace);
1436 if whitespace_margin == usize::MAX {
1437 whitespace_margin = 0;
1440 // Left-most column any visible span points at.
1441 let mut span_left_margin = usize::MAX;
1442 for line in &annotated_file.lines {
1443 for ann in &line.annotations {
1444 span_left_margin = min(span_left_margin, ann.start_col);
1445 span_left_margin = min(span_left_margin, ann.end_col);
1448 if span_left_margin == usize::MAX {
1449 span_left_margin = 0;
1452 // Right-most column any visible span points at.
1453 let mut span_right_margin = 0;
1454 let mut label_right_margin = 0;
1455 let mut max_line_len = 0;
1456 for line in &annotated_file.lines {
1459 annotated_file.file.get_line(line.line_index - 1).map_or(0, |s| s.len()),
1461 for ann in &line.annotations {
1462 span_right_margin = max(span_right_margin, ann.start_col);
1463 span_right_margin = max(span_right_margin, ann.end_col);
1464 // FIXME: account for labels not in the same line
1465 let label_right = ann.label.as_ref().map_or(0, |l| l.len() + 1);
1466 label_right_margin = max(label_right_margin, ann.end_col + label_right);
1470 let width_offset = 3 + max_line_num_len;
1471 let code_offset = if annotated_file.multiline_depth == 0 {
1474 width_offset + annotated_file.multiline_depth + 1
1477 let column_width = if let Some(width) = self.terminal_width {
1478 width.saturating_sub(code_offset)
1479 } else if self.ui_testing {
1480 DEFAULT_COLUMN_WIDTH
1482 termize::dimensions()
1483 .map(|(w, _)| w.saturating_sub(code_offset))
1484 .unwrap_or(DEFAULT_COLUMN_WIDTH)
1487 let margin = Margin::new(
1496 // Next, output the annotate source for this file
1497 for line_idx in 0..annotated_file.lines.len() {
1498 let previous_buffer_line = buffer.num_lines();
1500 let depths = self.render_source_line(
1502 annotated_file.file.clone(),
1503 &annotated_file.lines[line_idx],
1509 let mut to_add = FxHashMap::default();
1511 for (depth, style) in depths {
1512 if multilines.remove(&depth).is_none() {
1513 to_add.insert(depth, style);
1517 // Set the multiline annotation vertical lines to the left of
1518 // the code in this line.
1519 for (depth, style) in &multilines {
1520 for line in previous_buffer_line..buffer.num_lines() {
1521 draw_multiline_line(&mut buffer, line, width_offset, *depth, *style);
1524 // check to see if we need to print out or elide lines that come between
1525 // this annotated line and the next one.
1526 if line_idx < (annotated_file.lines.len() - 1) {
1527 let line_idx_delta = annotated_file.lines[line_idx + 1].line_index
1528 - annotated_file.lines[line_idx].line_index;
1529 if line_idx_delta > 2 {
1530 let last_buffer_line_num = buffer.num_lines();
1531 buffer.puts(last_buffer_line_num, 0, "...", Style::LineNumber);
1533 // Set the multiline annotation vertical lines on `...` bridging line.
1534 for (depth, style) in &multilines {
1535 draw_multiline_line(
1537 last_buffer_line_num,
1543 } else if line_idx_delta == 2 {
1544 let unannotated_line = annotated_file
1546 .get_line(annotated_file.lines[line_idx].line_index)
1547 .unwrap_or_else(|| Cow::from(""));
1549 let last_buffer_line_num = buffer.num_lines();
1553 &normalize_whitespace(&unannotated_line),
1554 annotated_file.lines[line_idx + 1].line_index - 1,
1555 last_buffer_line_num,
1561 for (depth, style) in &multilines {
1562 draw_multiline_line(
1564 last_buffer_line_num,
1573 multilines.extend(&to_add);
1578 // final step: take our styled buffer, render it, then output it
1579 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1584 fn emit_suggestion_default(
1586 suggestion: &CodeSuggestion,
1588 max_line_num_len: usize,
1589 ) -> io::Result<()> {
1590 let sm = match self.sm {
1592 None => return Ok(()),
1595 // Render the replacements for each suggestion
1596 let suggestions = suggestion.splice_lines(&**sm);
1597 debug!("emit_suggestion_default: suggestions={:?}", suggestions);
1599 if suggestions.is_empty() {
1600 // Suggestions coming from macros can have malformed spans. This is a heavy handed
1601 // approach to avoid ICEs by ignoring the suggestion outright.
1605 let mut buffer = StyledBuffer::new();
1607 // Render the suggestion message
1608 buffer.append(0, level.to_str(), Style::Level(*level));
1609 buffer.append(0, ": ", Style::HeaderMsg);
1613 &[(suggestion.msg.to_owned(), Style::NoStyle)],
1616 Some(Style::HeaderMsg),
1619 let mut row_num = 2;
1620 draw_col_separator_no_space(&mut buffer, 1, max_line_num_len + 1);
1621 let mut notice_capitalization = false;
1622 for (complete, parts, highlights, only_capitalization) in
1623 suggestions.iter().take(MAX_SUGGESTIONS)
1625 notice_capitalization |= only_capitalization;
1626 // Only show underline if the suggestion spans a single line and doesn't cover the
1627 // entirety of the code output. If you have multiple replacements in the same line
1628 // of code, show the underline.
1629 let show_underline = !(parts.len() == 1 && parts[0].snippet.trim() == complete.trim())
1630 && complete.lines().count() == 1;
1632 let has_deletion = parts.iter().any(|p| p.is_deletion());
1633 let is_multiline = complete.lines().count() > 1;
1635 let show_diff = has_deletion && !is_multiline;
1642 .span_to_lines(parts[0].span)
1643 .expect("span_to_lines failed when emitting suggestion");
1645 assert!(!file_lines.lines.is_empty() || parts[0].span.is_dummy());
1647 let line_start = sm.lookup_char_pos(parts[0].span.lo()).line;
1648 draw_col_separator_no_space(&mut buffer, 1, max_line_num_len + 1);
1649 let mut lines = complete.lines();
1650 for (line_pos, (line, highlight_parts)) in
1651 lines.by_ref().zip(highlights).take(MAX_SUGGESTION_HIGHLIGHT_LINES).enumerate()
1653 // Print the span column to avoid confusion
1657 &self.maybe_anonymized(line_start + line_pos),
1661 // Add the line number for both addition and removal to drive the point home.
1663 // N - fn foo<A: T>(bar: A) {
1664 // N + fn foo(bar: impl T) {
1668 &self.maybe_anonymized(line_start + line_pos),
1671 buffer.puts(row_num - 1, max_line_num_len + 1, "- ", Style::Removal);
1674 max_line_num_len + 3,
1675 &normalize_whitespace(
1678 .get_line(file_lines.lines[line_pos].line_index)
1683 buffer.puts(row_num, max_line_num_len + 1, "+ ", Style::Addition);
1684 } else if is_multiline {
1685 match &highlight_parts[..] {
1686 [SubstitutionHighlight { start: 0, end }] if *end == line.len() => {
1687 buffer.puts(row_num, max_line_num_len + 1, "+ ", Style::Addition);
1690 draw_col_separator(&mut buffer, row_num, max_line_num_len + 1);
1693 buffer.puts(row_num, max_line_num_len + 1, "~ ", Style::Addition);
1697 draw_col_separator(&mut buffer, row_num, max_line_num_len + 1);
1700 // print the suggestion
1701 buffer.append(row_num, &normalize_whitespace(line), Style::NoStyle);
1703 // Colorize addition/replacements with green.
1704 for &SubstitutionHighlight { start, end } in highlight_parts {
1705 // Account for tabs when highlighting (#87972).
1706 let tabs: usize = line
1709 .map(|ch| match ch {
1714 buffer.set_style_range(
1716 max_line_num_len + 3 + start + tabs,
1717 max_line_num_len + 3 + end + tabs,
1725 // This offset and the ones below need to be signed to account for replacement code
1726 // that is shorter than the original code.
1727 let mut offsets: Vec<(usize, isize)> = Vec::new();
1728 // Only show an underline in the suggestions if the suggestion is not the
1729 // entirety of the code being shown and the displayed code is not multiline.
1731 draw_col_separator(&mut buffer, row_num, max_line_num_len + 1);
1733 let span_start_pos = sm.lookup_char_pos(part.span.lo()).col_display;
1734 let span_end_pos = sm.lookup_char_pos(part.span.hi()).col_display;
1736 // Do not underline the leading...
1737 let start = part.snippet.len().saturating_sub(part.snippet.trim_start().len());
1738 // ...or trailing spaces. Account for substitutions containing unicode
1740 let sub_len: usize = part
1744 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
1747 let offset: isize = offsets
1750 |(start, v)| if span_start_pos <= *start { None } else { Some(v) },
1753 let underline_start = (span_start_pos + start) as isize + offset;
1754 let underline_end = (span_start_pos + start + sub_len) as isize + offset;
1755 assert!(underline_start >= 0 && underline_end >= 0);
1756 let padding: usize = max_line_num_len + 3;
1757 for p in underline_start..underline_end {
1759 // If this is a replacement, underline with `^`, if this is an addition
1760 // underline with `+`.
1763 (padding as isize + p) as usize,
1764 if part.is_addition(&sm) { '+' } else { '~' },
1770 // Colorize removal with red in diff format.
1771 buffer.set_style_range(
1773 (padding as isize + span_start_pos as isize) as usize,
1774 (padding as isize + span_end_pos as isize) as usize,
1780 // length of the code after substitution
1781 let full_sub_len = part
1784 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
1785 .sum::<usize>() as isize;
1787 // length of the code to be substituted
1788 let snippet_len = span_end_pos as isize - span_start_pos as isize;
1789 // For multiple substitutions, use the position *after* the previous
1790 // substitutions have happened, only when further substitutions are
1791 // located strictly after.
1792 offsets.push((span_end_pos, full_sub_len - snippet_len));
1797 // if we elided some lines, add an ellipsis
1798 if lines.next().is_some() {
1799 buffer.puts(row_num, max_line_num_len - 1, "...", Style::LineNumber);
1800 } else if !show_underline {
1801 draw_col_separator_no_space(&mut buffer, row_num, max_line_num_len + 1);
1805 if suggestions.len() > MAX_SUGGESTIONS {
1806 let others = suggestions.len() - MAX_SUGGESTIONS;
1807 let msg = format!("and {} other candidate{}", others, pluralize!(others));
1808 buffer.puts(row_num, max_line_num_len + 3, &msg, Style::NoStyle);
1809 } else if notice_capitalization {
1810 let msg = "notice the capitalization difference";
1811 buffer.puts(row_num, max_line_num_len + 3, &msg, Style::NoStyle);
1813 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1817 fn emit_messages_default(
1820 message: &[(String, Style)],
1821 code: &Option<DiagnosticId>,
1823 children: &[SubDiagnostic],
1824 suggestions: &[CodeSuggestion],
1826 let max_line_num_len = if self.ui_testing {
1827 ANONYMIZED_LINE_NUM.len()
1829 let n = self.get_max_line_num(span, children);
1830 num_decimal_digits(n)
1833 match self.emit_message_default(span, message, code, level, max_line_num_len, false) {
1835 if !children.is_empty()
1836 || suggestions.iter().any(|s| s.style != SuggestionStyle::CompletelyHidden)
1838 let mut buffer = StyledBuffer::new();
1839 if !self.short_message {
1840 draw_col_separator_no_space(&mut buffer, 0, max_line_num_len + 1);
1842 if let Err(e) = emit_to_destination(
1848 panic!("failed to emit error: {}", e)
1851 if !self.short_message {
1852 for child in children {
1853 let span = child.render_span.as_ref().unwrap_or(&child.span);
1854 if let Err(err) = self.emit_message_default(
1856 &child.styled_message(),
1862 panic!("failed to emit error: {}", err);
1865 for sugg in suggestions {
1866 if sugg.style == SuggestionStyle::CompletelyHidden {
1867 // do not display this suggestion, it is meant only for tools
1868 } else if sugg.style == SuggestionStyle::HideCodeAlways {
1869 if let Err(e) = self.emit_message_default(
1871 &[(sugg.msg.to_owned(), Style::HeaderMsg)],
1877 panic!("failed to emit error: {}", e);
1879 } else if let Err(e) =
1880 self.emit_suggestion_default(sugg, &Level::Help, max_line_num_len)
1882 panic!("failed to emit error: {}", e);
1887 Err(e) => panic!("failed to emit error: {}", e),
1890 let mut dst = self.dst.writable();
1891 match writeln!(dst) {
1892 Err(e) => panic!("failed to emit error: {}", e),
1894 if let Err(e) = dst.flush() {
1895 panic!("failed to emit error: {}", e)
1902 impl FileWithAnnotatedLines {
1903 /// Preprocess all the annotations so that they are grouped by file and by line number
1904 /// This helps us quickly iterate over the whole message (including secondary file spans)
1905 pub fn collect_annotations(
1907 source_map: &Option<Lrc<SourceMap>>,
1908 ) -> Vec<FileWithAnnotatedLines> {
1909 fn add_annotation_to_file(
1910 file_vec: &mut Vec<FileWithAnnotatedLines>,
1911 file: Lrc<SourceFile>,
1915 for slot in file_vec.iter_mut() {
1916 // Look through each of our files for the one we're adding to
1917 if slot.file.name == file.name {
1918 // See if we already have a line for it
1919 for line_slot in &mut slot.lines {
1920 if line_slot.line_index == line_index {
1921 line_slot.annotations.push(ann);
1925 // We don't have a line yet, create one
1926 slot.lines.push(Line { line_index, annotations: vec![ann] });
1931 // This is the first time we're seeing the file
1932 file_vec.push(FileWithAnnotatedLines {
1934 lines: vec![Line { line_index, annotations: vec![ann] }],
1939 let mut output = vec![];
1940 let mut multiline_annotations = vec![];
1942 if let Some(ref sm) = source_map {
1943 for span_label in msp.span_labels() {
1944 if span_label.span.is_dummy() {
1948 let lo = sm.lookup_char_pos(span_label.span.lo());
1949 let mut hi = sm.lookup_char_pos(span_label.span.hi());
1951 // Watch out for "empty spans". If we get a span like 6..6, we
1952 // want to just display a `^` at 6, so convert that to
1953 // 6..7. This is degenerate input, but it's best to degrade
1954 // gracefully -- and the parser likes to supply a span like
1955 // that for EOF, in particular.
1957 if lo.col_display == hi.col_display && lo.line == hi.line {
1958 hi.col_display += 1;
1961 if lo.line != hi.line {
1962 let ml = MultilineAnnotation {
1964 line_start: lo.line,
1966 start_col: lo.col_display,
1967 end_col: hi.col_display,
1968 is_primary: span_label.is_primary,
1969 label: span_label.label,
1970 overlaps_exactly: false,
1972 multiline_annotations.push((lo.file, ml));
1974 let ann = Annotation {
1975 start_col: lo.col_display,
1976 end_col: hi.col_display,
1977 is_primary: span_label.is_primary,
1978 label: span_label.label,
1979 annotation_type: AnnotationType::Singleline,
1981 add_annotation_to_file(&mut output, lo.file, lo.line, ann);
1986 // Find overlapping multiline annotations, put them at different depths
1987 multiline_annotations.sort_by_key(|&(_, ref ml)| (ml.line_start, ml.line_end));
1988 for (_, ann) in multiline_annotations.clone() {
1989 for (_, a) in multiline_annotations.iter_mut() {
1990 // Move all other multiline annotations overlapping with this one
1991 // one level to the right.
1992 if !(ann.same_span(a))
1993 && num_overlap(ann.line_start, ann.line_end, a.line_start, a.line_end, true)
1996 } else if ann.same_span(a) && &ann != a {
1997 a.overlaps_exactly = true;
2004 let mut max_depth = 0; // max overlapping multiline spans
2005 for (file, ann) in multiline_annotations {
2006 max_depth = max(max_depth, ann.depth);
2007 let mut end_ann = ann.as_end();
2008 if !ann.overlaps_exactly {
2009 // avoid output like
2031 add_annotation_to_file(&mut output, file.clone(), ann.line_start, ann.as_start());
2032 // 4 is the minimum vertical length of a multiline span when presented: two lines
2033 // of code and two lines of underline. This is not true for the special case where
2034 // the beginning doesn't have an underline, but the current logic seems to be
2035 // working correctly.
2036 let middle = min(ann.line_start + 4, ann.line_end);
2037 for line in ann.line_start + 1..middle {
2038 // Every `|` that joins the beginning of the span (`___^`) to the end (`|__^`).
2039 add_annotation_to_file(&mut output, file.clone(), line, ann.as_line());
2041 let line_end = ann.line_end - 1;
2042 if middle < line_end {
2043 add_annotation_to_file(&mut output, file.clone(), line_end, ann.as_line());
2046 end_ann.annotation_type = AnnotationType::Singleline;
2048 add_annotation_to_file(&mut output, file, ann.line_end, end_ann);
2050 for file_vec in output.iter_mut() {
2051 file_vec.multiline_depth = max_depth;
2057 // instead of taking the String length or dividing by 10 while > 0, we multiply a limit by 10 until
2058 // we're higher. If the loop isn't exited by the `return`, the last multiplication will wrap, which
2059 // is OK, because while we cannot fit a higher power of 10 in a usize, the loop will end anyway.
2060 // This is also why we need the max number of decimal digits within a `usize`.
2061 fn num_decimal_digits(num: usize) -> usize {
2062 #[cfg(target_pointer_width = "64")]
2063 const MAX_DIGITS: usize = 20;
2065 #[cfg(target_pointer_width = "32")]
2066 const MAX_DIGITS: usize = 10;
2068 #[cfg(target_pointer_width = "16")]
2069 const MAX_DIGITS: usize = 5;
2072 for num_digits in 1..MAX_DIGITS {
2076 lim = lim.wrapping_mul(10);
2081 // We replace some characters so the CLI output is always consistent and underlines aligned.
2082 const OUTPUT_REPLACEMENTS: &[(char, &str)] = &[
2083 ('\t', " "), // We do our own tab replacement
2084 ('\u{200D}', ""), // Replace ZWJ with nothing for consistent terminal output of grapheme clusters.
2085 ('\u{202A}', ""), // The following unicode text flow control characters are inconsistently
2086 ('\u{202B}', ""), // supported accross CLIs and can cause confusion due to the bytes on disk
2087 ('\u{202D}', ""), // not corresponding to the visible source code, so we replace them always.
2096 fn normalize_whitespace(str: &str) -> String {
2097 let mut s = str.to_string();
2098 for (c, replacement) in OUTPUT_REPLACEMENTS {
2099 s = s.replace(*c, replacement);
2104 fn draw_col_separator(buffer: &mut StyledBuffer, line: usize, col: usize) {
2105 buffer.puts(line, col, "| ", Style::LineNumber);
2108 fn draw_col_separator_no_space(buffer: &mut StyledBuffer, line: usize, col: usize) {
2109 draw_col_separator_no_space_with_style(buffer, line, col, Style::LineNumber);
2112 fn draw_col_separator_no_space_with_style(
2113 buffer: &mut StyledBuffer,
2118 buffer.putc(line, col, '|', style);
2122 buffer: &mut StyledBuffer,
2129 for col in col_from..col_to {
2130 buffer.putc(line, col, symbol, style);
2134 fn draw_note_separator(buffer: &mut StyledBuffer, line: usize, col: usize) {
2135 buffer.puts(line, col, "= ", Style::LineNumber);
2138 fn draw_multiline_line(
2139 buffer: &mut StyledBuffer,
2145 buffer.putc(line, offset + depth - 1, '|', style);
2155 let extra = if inclusive { 1 } else { 0 };
2156 (b_start..b_end + extra).contains(&a_start) || (a_start..a_end + extra).contains(&b_start)
2158 fn overlaps(a1: &Annotation, a2: &Annotation, padding: usize) -> bool {
2159 num_overlap(a1.start_col, a1.end_col + padding, a2.start_col, a2.end_col, false)
2162 fn emit_to_destination(
2163 rendered_buffer: &[Vec<StyledString>],
2165 dst: &mut Destination,
2166 short_message: bool,
2167 ) -> io::Result<()> {
2170 let mut dst = dst.writable();
2172 // In order to prevent error message interleaving, where multiple error lines get intermixed
2173 // when multiple compiler processes error simultaneously, we emit errors with additional
2176 // On Unix systems, we write into a buffered terminal rather than directly to a terminal. When
2177 // the .flush() is called we take the buffer created from the buffered writes and write it at
2178 // one shot. Because the Unix systems use ANSI for the colors, which is a text-based styling
2179 // scheme, this buffered approach works and maintains the styling.
2181 // On Windows, styling happens through calls to a terminal API. This prevents us from using the
2182 // same buffering approach. Instead, we use a global Windows mutex, which we acquire long
2183 // enough to output the full error message, then we release.
2184 let _buffer_lock = lock::acquire_global_lock("rustc_errors");
2185 for (pos, line) in rendered_buffer.iter().enumerate() {
2187 dst.apply_style(*lvl, part.style)?;
2188 write!(dst, "{}", part.text)?;
2191 if !short_message && (!lvl.is_failure_note() || pos != rendered_buffer.len() - 1) {
2199 pub enum Destination {
2200 Terminal(StandardStream),
2201 Buffered(BufferWriter),
2202 // The bool denotes whether we should be emitting ansi color codes or not
2203 Raw(Box<(dyn Write + Send)>, bool),
2206 pub enum WritableDst<'a> {
2207 Terminal(&'a mut StandardStream),
2208 Buffered(&'a mut BufferWriter, Buffer),
2209 Raw(&'a mut (dyn Write + Send)),
2210 ColoredRaw(Ansi<&'a mut (dyn Write + Send)>),
2214 fn from_stderr(color: ColorConfig) -> Destination {
2215 let choice = color.to_color_choice();
2216 // On Windows we'll be performing global synchronization on the entire
2217 // system for emitting rustc errors, so there's no need to buffer
2220 // On non-Windows we rely on the atomicity of `write` to ensure errors
2221 // don't get all jumbled up.
2223 Terminal(StandardStream::stderr(choice))
2225 Buffered(BufferWriter::stderr(choice))
2229 fn writable(&mut self) -> WritableDst<'_> {
2231 Destination::Terminal(ref mut t) => WritableDst::Terminal(t),
2232 Destination::Buffered(ref mut t) => {
2233 let buf = t.buffer();
2234 WritableDst::Buffered(t, buf)
2236 Destination::Raw(ref mut t, false) => WritableDst::Raw(t),
2237 Destination::Raw(ref mut t, true) => WritableDst::ColoredRaw(Ansi::new(t)),
2241 fn supports_color(&self) -> bool {
2243 Self::Terminal(ref stream) => stream.supports_color(),
2244 Self::Buffered(ref buffer) => buffer.buffer().supports_color(),
2245 Self::Raw(_, supports_color) => supports_color,
2250 impl<'a> WritableDst<'a> {
2251 fn apply_style(&mut self, lvl: Level, style: Style) -> io::Result<()> {
2252 let mut spec = ColorSpec::new();
2254 Style::Addition => {
2255 spec.set_fg(Some(Color::Green)).set_intense(true);
2258 spec.set_fg(Some(Color::Red)).set_intense(true);
2260 Style::LineAndColumn => {}
2261 Style::LineNumber => {
2262 spec.set_bold(true);
2263 spec.set_intense(true);
2265 spec.set_fg(Some(Color::Cyan));
2267 spec.set_fg(Some(Color::Blue));
2270 Style::Quotation => {}
2271 Style::MainHeaderMsg => {
2272 spec.set_bold(true);
2274 spec.set_intense(true).set_fg(Some(Color::White));
2277 Style::UnderlinePrimary | Style::LabelPrimary => {
2279 spec.set_bold(true);
2281 Style::UnderlineSecondary | Style::LabelSecondary => {
2282 spec.set_bold(true).set_intense(true);
2284 spec.set_fg(Some(Color::Cyan));
2286 spec.set_fg(Some(Color::Blue));
2289 Style::HeaderMsg | Style::NoStyle => {}
2290 Style::Level(lvl) => {
2292 spec.set_bold(true);
2294 Style::Highlight => {
2295 spec.set_bold(true);
2298 self.set_color(&spec)
2301 fn set_color(&mut self, color: &ColorSpec) -> io::Result<()> {
2303 WritableDst::Terminal(ref mut t) => t.set_color(color),
2304 WritableDst::Buffered(_, ref mut t) => t.set_color(color),
2305 WritableDst::ColoredRaw(ref mut t) => t.set_color(color),
2306 WritableDst::Raw(_) => Ok(()),
2310 fn reset(&mut self) -> io::Result<()> {
2312 WritableDst::Terminal(ref mut t) => t.reset(),
2313 WritableDst::Buffered(_, ref mut t) => t.reset(),
2314 WritableDst::ColoredRaw(ref mut t) => t.reset(),
2315 WritableDst::Raw(_) => Ok(()),
2320 impl<'a> Write for WritableDst<'a> {
2321 fn write(&mut self, bytes: &[u8]) -> io::Result<usize> {
2323 WritableDst::Terminal(ref mut t) => t.write(bytes),
2324 WritableDst::Buffered(_, ref mut buf) => buf.write(bytes),
2325 WritableDst::Raw(ref mut w) => w.write(bytes),
2326 WritableDst::ColoredRaw(ref mut t) => t.write(bytes),
2330 fn flush(&mut self) -> io::Result<()> {
2332 WritableDst::Terminal(ref mut t) => t.flush(),
2333 WritableDst::Buffered(_, ref mut buf) => buf.flush(),
2334 WritableDst::Raw(ref mut w) => w.flush(),
2335 WritableDst::ColoredRaw(ref mut w) => w.flush(),
2340 impl<'a> Drop for WritableDst<'a> {
2341 fn drop(&mut self) {
2342 if let WritableDst::Buffered(ref mut dst, ref mut buf) = self {
2343 drop(dst.print(buf));
2348 /// Whether the original and suggested code are visually similar enough to warrant extra wording.
2349 pub fn is_case_difference(sm: &SourceMap, suggested: &str, sp: Span) -> bool {
2350 // FIXME: this should probably be extended to also account for `FO0` → `FOO` and unicode.
2351 let found = match sm.span_to_snippet(sp) {
2352 Ok(snippet) => snippet,
2354 warn!(error = ?e, "Invalid span {:?}", sp);
2358 let ascii_confusables = &['c', 'f', 'i', 'k', 'o', 's', 'u', 'v', 'w', 'x', 'y', 'z'];
2359 // All the chars that differ in capitalization are confusable (above):
2360 let confusable = iter::zip(found.chars(), suggested.chars())
2361 .filter(|(f, s)| f != s)
2362 .all(|(f, s)| (ascii_confusables.contains(&f) || ascii_confusables.contains(&s)));
2363 confusable && found.to_lowercase() == suggested.to_lowercase()
2364 // FIXME: We sometimes suggest the same thing we already have, which is a
2365 // bug, but be defensive against that here.
2366 && found != suggested