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::{FileLines, SourceFile, Span};
15 use crate::snippet::{Annotation, AnnotationType, Line, MultilineAnnotation, Style, StyledString};
16 use crate::styled_buffer::StyledBuffer;
17 use crate::translation::{to_fluent_args, Translate};
19 diagnostic::DiagnosticLocation, CodeSuggestion, Diagnostic, DiagnosticId, DiagnosticMessage,
20 FluentBundle, Handler, LazyFallbackBundle, Level, MultiSpan, SubDiagnostic,
21 SubstitutionHighlight, SuggestionStyle,
23 use rustc_lint_defs::pluralize;
25 use rustc_data_structures::fx::{FxHashMap, FxIndexMap};
26 use rustc_data_structures::sync::Lrc;
27 use rustc_error_messages::FluentArgs;
28 use rustc_span::hygiene::{ExpnKind, MacroKind};
30 use std::cmp::{max, min, Reverse};
32 use std::io::prelude::*;
35 use termcolor::{Ansi, BufferWriter, ColorChoice, ColorSpec, StandardStream};
36 use termcolor::{Buffer, Color, WriteColor};
38 /// Default column width, used in tests and when terminal dimensions cannot be determined.
39 const DEFAULT_COLUMN_WIDTH: usize = 140;
41 /// Describes the way the content of the `rendered` field of the json output is generated
42 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
43 pub enum HumanReadableErrorType {
45 AnnotateSnippet(ColorConfig),
49 impl HumanReadableErrorType {
50 /// Returns a (`short`, `color`) tuple
51 pub fn unzip(self) -> (bool, ColorConfig) {
53 HumanReadableErrorType::Default(cc) => (false, cc),
54 HumanReadableErrorType::Short(cc) => (true, cc),
55 HumanReadableErrorType::AnnotateSnippet(cc) => (false, cc),
60 dst: Box<dyn Write + Send>,
61 source_map: Option<Lrc<SourceMap>>,
62 bundle: Option<Lrc<FluentBundle>>,
63 fallback_bundle: LazyFallbackBundle,
65 diagnostic_width: Option<usize>,
66 macro_backtrace: bool,
67 track_diagnostics: bool,
69 let (short, color_config) = self.unzip();
70 let color = color_config.suggests_using_colors();
86 #[derive(Clone, Copy, Debug)]
88 /// The available whitespace in the left that can be consumed when centering.
89 pub whitespace_left: usize,
90 /// The column of the beginning of left-most span.
92 /// The column of the end of right-most span.
93 pub span_right: usize,
94 /// The beginning of the line to be displayed.
95 pub computed_left: usize,
96 /// The end of the line to be displayed.
97 pub computed_right: usize,
98 /// The current width of the terminal. Uses value of `DEFAULT_COLUMN_WIDTH` constant by default
100 pub column_width: usize,
101 /// The end column of a span label, including the span. Doesn't account for labels not in the
102 /// same line as the span.
103 pub label_right: usize,
108 whitespace_left: usize,
115 // The 6 is padding to give a bit of room for `...` when displaying:
120 // 16 | ... fn foo(self) -> Self::Bar {
125 whitespace_left: whitespace_left.saturating_sub(6),
126 span_left: span_left.saturating_sub(6),
127 span_right: span_right + 6,
131 label_right: label_right + 6,
133 m.compute(max_line_len);
137 fn was_cut_left(&self) -> bool {
138 self.computed_left > 0
141 fn was_cut_right(&self, line_len: usize) -> bool {
143 if self.computed_right == self.span_right || self.computed_right == self.label_right {
144 // Account for the "..." padding given above. Otherwise we end up with code lines that
145 // do fit but end in "..." as if they were trimmed.
146 self.computed_right - 6
150 right < line_len && self.computed_left + self.column_width < line_len
153 fn compute(&mut self, max_line_len: usize) {
154 // When there's a lot of whitespace (>20), we want to trim it as it is useless.
155 self.computed_left = if self.whitespace_left > 20 {
156 self.whitespace_left - 16 // We want some padding.
160 // We want to show as much as possible, max_line_len is the right-most boundary for the
162 self.computed_right = max(max_line_len, self.computed_left);
164 if self.computed_right - self.computed_left > self.column_width {
165 // Trimming only whitespace isn't enough, let's get craftier.
166 if self.label_right - self.whitespace_left <= self.column_width {
167 // Attempt to fit the code window only trimming whitespace.
168 self.computed_left = self.whitespace_left;
169 self.computed_right = self.computed_left + self.column_width;
170 } else if self.label_right - self.span_left <= self.column_width {
171 // Attempt to fit the code window considering only the spans and labels.
172 let padding_left = (self.column_width - (self.label_right - self.span_left)) / 2;
173 self.computed_left = self.span_left.saturating_sub(padding_left);
174 self.computed_right = self.computed_left + self.column_width;
175 } else if self.span_right - self.span_left <= self.column_width {
176 // Attempt to fit the code window considering the spans and labels plus padding.
177 let padding_left = (self.column_width - (self.span_right - self.span_left)) / 5 * 2;
178 self.computed_left = self.span_left.saturating_sub(padding_left);
179 self.computed_right = self.computed_left + self.column_width;
181 // Mostly give up but still don't show the full line.
182 self.computed_left = self.span_left;
183 self.computed_right = self.span_right;
188 fn left(&self, line_len: usize) -> usize {
189 min(self.computed_left, line_len)
192 fn right(&self, line_len: usize) -> usize {
193 if line_len.saturating_sub(self.computed_left) <= self.column_width {
196 min(line_len, self.computed_right)
201 const ANONYMIZED_LINE_NUM: &str = "LL";
203 /// Emitter trait for emitting errors.
204 pub trait Emitter: Translate {
205 /// Emit a structured diagnostic.
206 fn emit_diagnostic(&mut self, diag: &Diagnostic);
208 /// Emit a notification that an artifact has been output.
209 /// This is currently only supported for the JSON format,
210 /// other formats can, and will, simply ignore it.
211 fn emit_artifact_notification(&mut self, _path: &Path, _artifact_type: &str) {}
213 fn emit_future_breakage_report(&mut self, _diags: Vec<Diagnostic>) {}
215 /// Emit list of unused externs
216 fn emit_unused_externs(
218 _lint_level: rustc_lint_defs::Level,
219 _unused_externs: &[&str],
223 /// Checks if should show explanations about "rustc --explain"
224 fn should_show_explain(&self) -> bool {
228 /// Checks if we can use colors in the current output stream.
229 fn supports_color(&self) -> bool {
233 fn source_map(&self) -> Option<&Lrc<SourceMap>>;
235 /// Formats the substitutions of the primary_span
237 /// There are a lot of conditions to this method, but in short:
239 /// * If the current `Diagnostic` has only one visible `CodeSuggestion`,
240 /// we format the `help` suggestion depending on the content of the
241 /// substitutions. In that case, we return the modified span only.
243 /// * If the current `Diagnostic` has multiple suggestions,
244 /// we return the original `primary_span` and the original suggestions.
245 fn primary_span_formatted<'a>(
247 diag: &'a Diagnostic,
248 fluent_args: &FluentArgs<'_>,
249 ) -> (MultiSpan, &'a [CodeSuggestion]) {
250 let mut primary_span = diag.span.clone();
251 let suggestions = diag.suggestions.as_ref().map_or(&[][..], |suggestions| &suggestions[..]);
252 if let Some((sugg, rest)) = suggestions.split_first() {
253 let msg = self.translate_message(&sugg.msg, fluent_args);
254 if rest.is_empty() &&
255 // ^ if there is only one suggestion
256 // don't display multi-suggestions as labels
257 sugg.substitutions.len() == 1 &&
258 // don't display multipart suggestions as labels
259 sugg.substitutions[0].parts.len() == 1 &&
260 // don't display long messages as labels
261 msg.split_whitespace().count() < 10 &&
262 // don't display multiline suggestions as labels
263 !sugg.substitutions[0].parts[0].snippet.contains('\n') &&
265 // when this style is set we want the suggestion to be a message, not inline
266 SuggestionStyle::HideCodeAlways,
267 // trivial suggestion for tooling's sake, never shown
268 SuggestionStyle::CompletelyHidden,
269 // subtle suggestion, never shown inline
270 SuggestionStyle::ShowAlways,
271 ].contains(&sugg.style)
273 let substitution = &sugg.substitutions[0].parts[0].snippet.trim();
274 let msg = if substitution.is_empty() || sugg.style.hide_inline() {
275 // This substitution is only removal OR we explicitly don't want to show the
276 // code inline (`hide_inline`). Therefore, we don't show the substitution.
277 format!("help: {}", &msg)
279 // Show the default suggestion text with the substitution
285 .map(|sm| is_case_difference(
288 sugg.substitutions[0].parts[0].span,
292 " (notice the capitalization)"
299 primary_span.push_span_label(sugg.substitutions[0].parts[0].span, msg);
301 // We return only the modified primary_span
304 // if there are multiple suggestions, print them all in full
305 // to be consistent. We could try to figure out if we can
306 // make one (or the first one) inline, but that would give
307 // undue importance to a semi-random suggestion
308 (primary_span, suggestions)
311 (primary_span, suggestions)
315 fn fix_multispans_in_extern_macros_and_render_macro_backtrace(
317 source_map: &Option<Lrc<SourceMap>>,
318 span: &mut MultiSpan,
319 children: &mut Vec<SubDiagnostic>,
323 // Check for spans in macros, before `fix_multispans_in_extern_macros`
324 // has a chance to replace them.
325 let has_macro_spans: Vec<_> = iter::once(&*span)
326 .chain(children.iter().map(|child| &child.span))
327 .flat_map(|span| span.primary_spans())
328 .flat_map(|sp| sp.macro_backtrace())
329 .filter_map(|expn_data| {
330 match expn_data.kind {
331 ExpnKind::Root => None,
333 // Skip past non-macro entries, just in case there
334 // are some which do actually involve macros.
335 ExpnKind::Inlined | ExpnKind::Desugaring(..) | ExpnKind::AstPass(..) => None,
337 ExpnKind::Macro(macro_kind, name) => Some((macro_kind, name)),
343 self.fix_multispans_in_extern_macros(source_map, span, children);
346 self.render_multispans_macro_backtrace(span, children, backtrace);
349 if let Some((macro_kind, name)) = has_macro_spans.first() {
350 // Mark the actual macro this originates from
351 let and_then = if let Some((macro_kind, last_name)) = has_macro_spans.last()
354 let descr = macro_kind.descr();
356 " which comes from the expansion of the {descr} `{last_name}`",
362 let descr = macro_kind.descr();
364 "this {level} originates in the {descr} `{name}`{and_then} \
365 (in Nightly builds, run with -Z macro-backtrace for more info)",
368 children.push(SubDiagnostic {
370 message: vec![(DiagnosticMessage::Str(msg), Style::NoStyle)],
371 span: MultiSpan::new(),
378 fn render_multispans_macro_backtrace(
380 span: &mut MultiSpan,
381 children: &mut Vec<SubDiagnostic>,
384 for span in iter::once(span).chain(children.iter_mut().map(|child| &mut child.span)) {
385 self.render_multispan_macro_backtrace(span, backtrace);
389 fn render_multispan_macro_backtrace(&self, span: &mut MultiSpan, always_backtrace: bool) {
390 let mut new_labels: Vec<(Span, String)> = vec![];
392 for &sp in span.primary_spans() {
397 // FIXME(eddyb) use `retain` on `macro_backtrace` to remove all the
398 // entries we don't want to print, to make sure the indices being
399 // printed are contiguous (or omitted if there's only one entry).
400 let macro_backtrace: Vec<_> = sp.macro_backtrace().collect();
401 for (i, trace) in macro_backtrace.iter().rev().enumerate() {
402 if trace.def_site.is_dummy() {
406 if always_backtrace && !matches!(trace.kind, ExpnKind::Inlined) {
410 "in this expansion of `{}`{}",
412 if macro_backtrace.len() > 1 {
413 // if macro_backtrace.len() == 1 it'll be
414 // pointed at by "in this macro invocation"
415 format!(" (#{})", i + 1)
423 // Don't add a label on the call site if the diagnostic itself
424 // already points to (a part of) that call site, as the label
425 // is meant for showing the relevant invocation when the actual
426 // diagnostic is pointing to some part of macro definition.
428 // This also handles the case where an external span got replaced
429 // with the call site span by `fix_multispans_in_extern_macros`.
431 // NB: `-Zmacro-backtrace` overrides this, for uniformity, as the
432 // "in this expansion of" label above is always added in that mode,
433 // and it needs an "in this macro invocation" label to match that.
434 let redundant_span = trace.call_site.contains(sp);
436 if !redundant_span || always_backtrace {
437 let msg: Cow<'static, _> = match trace.kind {
438 ExpnKind::Macro(MacroKind::Attr, _) => {
439 "this procedural macro expansion".into()
441 ExpnKind::Macro(MacroKind::Derive, _) => {
442 "this derive macro expansion".into()
444 ExpnKind::Macro(MacroKind::Bang, _) => "this macro invocation".into(),
445 ExpnKind::Inlined => "this inlined function call".into(),
446 ExpnKind::Root => "the crate root".into(),
447 ExpnKind::AstPass(kind) => kind.descr().into(),
448 ExpnKind::Desugaring(kind) => {
449 format!("this {} desugaring", kind.descr()).into()
457 if macro_backtrace.len() > 1 && always_backtrace {
458 // only specify order when the macro
459 // backtrace is multiple levels deep
460 format!(" (#{})", i + 1)
467 if !always_backtrace {
473 for (label_span, label_text) in new_labels {
474 span.push_span_label(label_span, label_text);
478 // This does a small "fix" for multispans by looking to see if it can find any that
479 // point directly at external macros. Since these are often difficult to read,
480 // this will change the span to point at the use site.
481 fn fix_multispans_in_extern_macros(
483 source_map: &Option<Lrc<SourceMap>>,
484 span: &mut MultiSpan,
485 children: &mut Vec<SubDiagnostic>,
487 let Some(source_map) = source_map else { return };
488 debug!("fix_multispans_in_extern_macros: before: span={:?} children={:?}", span, children);
489 self.fix_multispan_in_extern_macros(source_map, span);
490 for child in children.iter_mut() {
491 self.fix_multispan_in_extern_macros(source_map, &mut child.span);
493 debug!("fix_multispans_in_extern_macros: after: span={:?} children={:?}", span, children);
496 // This "fixes" MultiSpans that contain `Span`s pointing to locations inside of external macros.
497 // Since these locations are often difficult to read,
498 // we move these spans from the external macros to their corresponding use site.
499 fn fix_multispan_in_extern_macros(&self, source_map: &Lrc<SourceMap>, span: &mut MultiSpan) {
500 // First, find all the spans in external macros and point instead at their use site.
501 let replacements: Vec<(Span, Span)> = span
505 .chain(span.span_labels().iter().map(|sp_label| sp_label.span))
507 if !sp.is_dummy() && source_map.is_imported(sp) {
508 let maybe_callsite = sp.source_callsite();
509 if sp != maybe_callsite {
510 return Some((sp, maybe_callsite));
517 // After we have them, make sure we replace these 'bad' def sites with their use sites.
518 for (from, to) in replacements {
519 span.replace(from, to);
524 impl Translate for EmitterWriter {
525 fn fluent_bundle(&self) -> Option<&Lrc<FluentBundle>> {
526 self.fluent_bundle.as_ref()
529 fn fallback_fluent_bundle(&self) -> &FluentBundle {
530 &**self.fallback_bundle
534 impl Emitter for EmitterWriter {
535 fn source_map(&self) -> Option<&Lrc<SourceMap>> {
539 fn emit_diagnostic(&mut self, diag: &Diagnostic) {
540 let fluent_args = to_fluent_args(diag.args());
542 let mut children = diag.children.clone();
543 let (mut primary_span, suggestions) = self.primary_span_formatted(&diag, &fluent_args);
544 debug!("emit_diagnostic: suggestions={:?}", suggestions);
546 self.fix_multispans_in_extern_macros_and_render_macro_backtrace(
551 self.macro_backtrace,
554 self.emit_messages_default(
562 self.track_diagnostics.then_some(&diag.emitted_at),
566 fn should_show_explain(&self) -> bool {
570 fn supports_color(&self) -> bool {
571 self.dst.supports_color()
575 /// An emitter that does nothing when emitting a non-fatal diagnostic.
576 /// Fatal diagnostics are forwarded to `fatal_handler` to avoid silent
577 /// failures of rustc, as witnessed e.g. in issue #89358.
578 pub struct SilentEmitter {
579 pub fatal_handler: Handler,
580 pub fatal_note: Option<String>,
583 impl Translate for SilentEmitter {
584 fn fluent_bundle(&self) -> Option<&Lrc<FluentBundle>> {
588 fn fallback_fluent_bundle(&self) -> &FluentBundle {
589 panic!("silent emitter attempted to translate message")
593 impl Emitter for SilentEmitter {
594 fn source_map(&self) -> Option<&Lrc<SourceMap>> {
598 fn emit_diagnostic(&mut self, d: &Diagnostic) {
599 if d.level == Level::Fatal {
600 let mut d = d.clone();
601 if let Some(ref note) = self.fatal_note {
604 self.fatal_handler.emit_diagnostic(&mut d);
609 /// Maximum number of suggestions to be shown
611 /// Arbitrary, but taken from trait import suggestion limit
612 pub const MAX_SUGGESTIONS: usize = 4;
614 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
615 pub enum ColorConfig {
622 fn to_color_choice(self) -> ColorChoice {
624 ColorConfig::Always => {
625 if atty::is(atty::Stream::Stderr) {
628 ColorChoice::AlwaysAnsi
631 ColorConfig::Never => ColorChoice::Never,
632 ColorConfig::Auto if atty::is(atty::Stream::Stderr) => ColorChoice::Auto,
633 ColorConfig::Auto => ColorChoice::Never,
636 fn suggests_using_colors(self) -> bool {
638 ColorConfig::Always | ColorConfig::Auto => true,
639 ColorConfig::Never => false,
644 /// Handles the writing of `HumanReadableErrorType::Default` and `HumanReadableErrorType::Short`
645 pub struct EmitterWriter {
647 sm: Option<Lrc<SourceMap>>,
648 fluent_bundle: Option<Lrc<FluentBundle>>,
649 fallback_bundle: LazyFallbackBundle,
653 diagnostic_width: Option<usize>,
655 macro_backtrace: bool,
656 track_diagnostics: bool,
660 pub struct FileWithAnnotatedLines {
661 pub file: Lrc<SourceFile>,
662 pub lines: Vec<Line>,
663 multiline_depth: usize,
668 color_config: ColorConfig,
669 source_map: Option<Lrc<SourceMap>>,
670 fluent_bundle: Option<Lrc<FluentBundle>>,
671 fallback_bundle: LazyFallbackBundle,
674 diagnostic_width: Option<usize>,
675 macro_backtrace: bool,
676 track_diagnostics: bool,
678 let dst = Destination::from_stderr(color_config);
694 dst: Box<dyn Write + Send>,
695 source_map: Option<Lrc<SourceMap>>,
696 fluent_bundle: Option<Lrc<FluentBundle>>,
697 fallback_bundle: LazyFallbackBundle,
701 diagnostic_width: Option<usize>,
702 macro_backtrace: bool,
703 track_diagnostics: bool,
706 dst: Raw(dst, colored),
719 pub fn ui_testing(mut self, ui_testing: bool) -> Self {
720 self.ui_testing = ui_testing;
724 fn maybe_anonymized(&self, line_num: usize) -> Cow<'static, str> {
726 Cow::Borrowed(ANONYMIZED_LINE_NUM)
728 Cow::Owned(line_num.to_string())
734 buffer: &mut StyledBuffer,
742 // Tabs are assumed to have been replaced by spaces in calling code.
743 debug_assert!(!source_string.contains('\t'));
744 let line_len = source_string.len();
745 // Create the source line we will highlight.
746 let left = margin.left(line_len);
747 let right = margin.right(line_len);
748 // On long lines, we strip the source line, accounting for unicode.
750 let code: String = source_string
754 // Make sure that the trimming on the right will fall within the terminal width.
755 // FIXME: `unicode_width` sometimes disagrees with terminals on how wide a `char` is.
756 // For now, just accept that sometimes the code line will be longer than desired.
757 let next = unicode_width::UnicodeWidthChar::width(*ch).unwrap_or(1);
758 if taken + next > right - left {
765 buffer.puts(line_offset, code_offset, &code, Style::Quotation);
766 if margin.was_cut_left() {
767 // We have stripped some code/whitespace from the beginning, make it clear.
768 buffer.puts(line_offset, code_offset, "...", Style::LineNumber);
770 if margin.was_cut_right(line_len) {
771 // We have stripped some code after the right-most span end, make it clear we did so.
772 buffer.puts(line_offset, code_offset + taken - 3, "...", Style::LineNumber);
774 buffer.puts(line_offset, 0, &self.maybe_anonymized(line_index), Style::LineNumber);
776 draw_col_separator_no_space(buffer, line_offset, width_offset - 2);
779 fn render_source_line(
781 buffer: &mut StyledBuffer,
782 file: Lrc<SourceFile>,
787 ) -> Vec<(usize, Style)> {
793 // | secondary span label
795 // ^^ ^ ^^^ ^^^^ ^^^ we don't care about code too far to the right of a span, we trim it
797 // | | | actual code found in your source code and the spans we use to mark it
798 // | | when there's too much wasted space to the left, trim it
799 // | vertical divider between the column number and the code
802 if line.line_index == 0 {
806 let source_string = match file.get_line(line.line_index - 1) {
807 Some(s) => normalize_whitespace(&*s),
808 None => return Vec::new(),
811 let line_offset = buffer.num_lines();
814 let left = margin.left(source_string.len());
816 // Account for unicode characters of width !=0 that were removed.
817 let left = source_string
820 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
833 // Special case when there's only one annotation involved, it is the start of a multiline
834 // span and there's no text at the beginning of the code line. Instead of doing the whole
843 // we simplify the output to:
849 if let [ann] = &line.annotations[..] {
850 if let AnnotationType::MultilineStart(depth) = ann.annotation_type {
851 if source_string.chars().take(ann.start_col).all(|c| c.is_whitespace()) {
852 let style = if ann.is_primary {
853 Style::UnderlinePrimary
855 Style::UnderlineSecondary
857 buffer.putc(line_offset, width_offset + depth - 1, '/', style);
858 return vec![(depth, style)];
863 // We want to display like this:
865 // vec.push(vec.pop().unwrap());
866 // --- ^^^ - previous borrow ends here
868 // | error occurs here
869 // previous borrow of `vec` occurs here
871 // But there are some weird edge cases to be aware of:
873 // vec.push(vec.pop().unwrap());
874 // -------- - previous borrow ends here
876 // |this makes no sense
877 // previous borrow of `vec` occurs here
879 // For this reason, we group the lines into "highlight lines"
880 // and "annotations lines", where the highlight lines have the `^`.
882 // Sort the annotations by (start, end col)
883 // The labels are reversed, sort and then reversed again.
884 // Consider a list of annotations (A1, A2, C1, C2, B1, B2) where
885 // the letter signifies the span. Here we are only sorting by the
886 // span and hence, the order of the elements with the same span will
887 // not change. On reversing the ordering (|a, b| but b.cmp(a)), you get
888 // (C1, C2, B1, B2, A1, A2). All the elements with the same span are
889 // still ordered first to last, but all the elements with different
890 // spans are ordered by their spans in last to first order. Last to
891 // first order is important, because the jiggly lines and | are on
892 // the left, so the rightmost span needs to be rendered first,
893 // otherwise the lines would end up needing to go over a message.
895 let mut annotations = line.annotations.clone();
896 annotations.sort_by_key(|a| Reverse(a.start_col));
898 // First, figure out where each label will be positioned.
900 // In the case where you have the following annotations:
902 // vec.push(vec.pop().unwrap());
903 // -------- - previous borrow ends here [C]
905 // |this makes no sense [B]
906 // previous borrow of `vec` occurs here [A]
908 // `annotations_position` will hold [(2, A), (1, B), (0, C)].
910 // We try, when possible, to stick the rightmost annotation at the end
911 // of the highlight line:
913 // vec.push(vec.pop().unwrap());
914 // --- --- - previous borrow ends here
916 // But sometimes that's not possible because one of the other
917 // annotations overlaps it. For example, from the test
918 // `span_overlap_label`, we have the following annotations
919 // (written on distinct lines for clarity):
925 // In this case, we can't stick the rightmost-most label on
926 // the highlight line, or we would get:
933 // which is totally weird. Instead we want:
941 // which is...less weird, at least. In fact, in general, if
942 // the rightmost span overlaps with any other span, we should
943 // use the "hang below" version, so we can at least make it
944 // clear where the span *starts*. There's an exception for this
945 // logic, when the labels do not have a message:
960 let mut annotations_position = vec![];
961 let mut line_len = 0;
963 for (i, annotation) in annotations.iter().enumerate() {
964 for (j, next) in annotations.iter().enumerate() {
965 if overlaps(next, annotation, 0) // This label overlaps with another one and both
966 && annotation.has_label() // take space (they have text and are not
967 && j > i // multiline lines).
969 // We're currently on the first line, move the label one line down
971 // If we're overlapping with an un-labelled annotation with the same span
972 // we can just merge them in the output
973 if next.start_col == annotation.start_col
974 && next.end_col == annotation.end_col
980 // This annotation needs a new line in the output.
985 annotations_position.push((p, annotation));
986 for (j, next) in annotations.iter().enumerate() {
988 let l = next.label.as_ref().map_or(0, |label| label.len() + 2);
989 if (overlaps(next, annotation, l) // Do not allow two labels to be in the same
990 // line if they overlap including padding, to
991 // avoid situations like:
998 && annotation.has_label() // Both labels must have some text, otherwise
999 && next.has_label()) // they are not overlapping.
1000 // Do not add a new line if this annotation
1001 // or the next are vertical line placeholders.
1002 || (annotation.takes_space() // If either this or the next annotation is
1003 && next.has_label()) // multiline start/end, move it to a new line
1004 || (annotation.has_label() // so as not to overlap the horizontal lines.
1005 && next.takes_space())
1006 || (annotation.takes_space() && next.takes_space())
1007 || (overlaps(next, annotation, l)
1008 && next.end_col <= annotation.end_col
1013 // This annotation needs a new line in the output.
1019 line_len = max(line_len, p);
1026 // If there are no annotations or the only annotations on this line are
1027 // MultilineLine, then there's only code being shown, stop processing.
1028 if line.annotations.iter().all(|a| a.is_line()) {
1032 // Write the column separator.
1034 // After this we will have:
1043 for pos in 0..=line_len {
1044 draw_col_separator(buffer, line_offset + pos + 1, width_offset - 2);
1047 // Write the horizontal lines for multiline annotations
1048 // (only the first and last lines need this).
1050 // After this we will have:
1059 for &(pos, annotation) in &annotations_position {
1060 let style = if annotation.is_primary {
1061 Style::UnderlinePrimary
1063 Style::UnderlineSecondary
1066 match annotation.annotation_type {
1067 AnnotationType::MultilineStart(depth) | AnnotationType::MultilineEnd(depth) => {
1072 width_offset + depth,
1073 (code_offset + annotation.start_col).saturating_sub(left),
1077 _ if self.teach => {
1078 buffer.set_style_range(
1080 (code_offset + annotation.start_col).saturating_sub(left),
1081 (code_offset + annotation.end_col).saturating_sub(left),
1083 annotation.is_primary,
1090 // Write the vertical lines for labels that are on a different line as the underline.
1092 // After this we will have:
1101 for &(pos, annotation) in &annotations_position {
1102 let style = if annotation.is_primary {
1103 Style::UnderlinePrimary
1105 Style::UnderlineSecondary
1109 if pos > 1 && (annotation.has_label() || annotation.takes_space()) {
1110 for p in line_offset + 1..=line_offset + pos {
1113 (code_offset + annotation.start_col).saturating_sub(left),
1119 match annotation.annotation_type {
1120 AnnotationType::MultilineStart(depth) => {
1121 for p in line_offset + pos + 1..line_offset + line_len + 2 {
1122 buffer.putc(p, width_offset + depth - 1, '|', style);
1125 AnnotationType::MultilineEnd(depth) => {
1126 for p in line_offset..=line_offset + pos {
1127 buffer.putc(p, width_offset + depth - 1, '|', style);
1134 // Write the labels on the annotations that actually have a label.
1136 // After this we will have:
1141 // | something about `foo`
1145 for &(pos, annotation) in &annotations_position {
1147 if annotation.is_primary { Style::LabelPrimary } else { Style::LabelSecondary };
1148 let (pos, col) = if pos == 0 {
1149 (pos + 1, (annotation.end_col + 1).saturating_sub(left))
1151 (pos + 2, annotation.start_col.saturating_sub(left))
1153 if let Some(ref label) = annotation.label {
1154 buffer.puts(line_offset + pos, code_offset + col, &label, style);
1158 // Sort from biggest span to smallest span so that smaller spans are
1159 // represented in the output:
1164 // | | something about `foo`
1165 // | something about `fn foo()`
1166 annotations_position.sort_by_key(|(_, ann)| {
1167 // Decreasing order. When annotations share the same length, prefer `Primary`.
1168 (Reverse(ann.len()), ann.is_primary)
1171 // Write the underlines.
1173 // After this we will have:
1178 // | something about `foo`
1182 for &(_, annotation) in &annotations_position {
1183 let (underline, style) = if annotation.is_primary {
1184 ('^', Style::UnderlinePrimary)
1186 ('-', Style::UnderlineSecondary)
1188 for p in annotation.start_col..annotation.end_col {
1191 (code_offset + p).saturating_sub(left),
1197 annotations_position
1199 .filter_map(|&(_, annotation)| match annotation.annotation_type {
1200 AnnotationType::MultilineStart(p) | AnnotationType::MultilineEnd(p) => {
1201 let style = if annotation.is_primary {
1204 Style::LabelSecondary
1210 .collect::<Vec<_>>()
1213 fn get_multispan_max_line_num(&mut self, msp: &MultiSpan) -> usize {
1214 let Some(ref sm) = self.sm else {
1218 let will_be_emitted = |span: Span| {
1219 !span.is_dummy() && {
1220 let file = sm.lookup_source_file(span.hi());
1221 sm.ensure_source_file_source_present(file)
1226 for primary_span in msp.primary_spans() {
1227 if will_be_emitted(*primary_span) {
1228 let hi = sm.lookup_char_pos(primary_span.hi());
1229 max = (hi.line).max(max);
1232 if !self.short_message {
1233 for span_label in msp.span_labels() {
1234 if will_be_emitted(span_label.span) {
1235 let hi = sm.lookup_char_pos(span_label.span.hi());
1236 max = (hi.line).max(max);
1244 fn get_max_line_num(&mut self, span: &MultiSpan, children: &[SubDiagnostic]) -> usize {
1245 let primary = self.get_multispan_max_line_num(span);
1248 .map(|sub| self.get_multispan_max_line_num(&sub.span))
1254 /// Adds a left margin to every line but the first, given a padding length and the label being
1255 /// displayed, keeping the provided highlighting.
1258 buffer: &mut StyledBuffer,
1259 msg: &[(DiagnosticMessage, Style)],
1260 args: &FluentArgs<'_>,
1263 override_style: Option<Style>,
1265 // The extra 5 ` ` is padding that's always needed to align to the `note: `:
1268 // --> file.rs:13:20
1273 // = note: multiline
1278 // | | length of label
1280 // `max_line_num_len`
1281 let padding = " ".repeat(padding + label.len() + 5);
1283 /// Returns `override` if it is present and `style` is `NoStyle` or `style` otherwise
1284 fn style_or_override(style: Style, override_: Option<Style>) -> Style {
1285 match (style, override_) {
1286 (Style::NoStyle, Some(override_)) => override_,
1291 let mut line_number = 0;
1293 // Provided the following diagnostic message:
1297 // ("highlighted multiline\nstring to\nsee how it ", Style::NoStyle),
1298 // ("looks", Style::Highlight),
1299 // ("with\nvery ", Style::NoStyle),
1300 // ("weird", Style::Highlight),
1301 // (" formats\n", Style::NoStyle),
1302 // ("see?", Style::Highlight),
1305 // the expected output on a note is (* surround the highlighted text)
1307 // = note: highlighted multiline
1309 // see how it *looks* with
1310 // very *weird* formats
1312 for &(ref text, ref style) in msg.iter() {
1313 let text = self.translate_message(text, args);
1314 let lines = text.split('\n').collect::<Vec<_>>();
1315 if lines.len() > 1 {
1316 for (i, line) in lines.iter().enumerate() {
1319 buffer.append(line_number, &padding, Style::NoStyle);
1321 buffer.append(line_number, line, style_or_override(*style, override_style));
1324 buffer.append(line_number, &text, style_or_override(*style, override_style));
1329 fn emit_message_default(
1332 msg: &[(DiagnosticMessage, Style)],
1333 args: &FluentArgs<'_>,
1334 code: &Option<DiagnosticId>,
1336 max_line_num_len: usize,
1338 emitted_at: Option<&DiagnosticLocation>,
1339 ) -> io::Result<()> {
1340 let mut buffer = StyledBuffer::new();
1342 if !msp.has_primary_spans() && !msp.has_span_labels() && is_secondary && !self.short_message
1344 // This is a secondary message with no span info
1345 for _ in 0..max_line_num_len {
1346 buffer.prepend(0, " ", Style::NoStyle);
1348 draw_note_separator(&mut buffer, 0, max_line_num_len + 1);
1349 if *level != Level::FailureNote {
1350 buffer.append(0, level.to_str(), Style::MainHeaderMsg);
1351 buffer.append(0, ": ", Style::NoStyle);
1353 self.msg_to_buffer(&mut buffer, msg, args, max_line_num_len, "note", None);
1355 let mut label_width = 0;
1356 // The failure note level itself does not provide any useful diagnostic information
1357 if *level != Level::FailureNote {
1358 buffer.append(0, level.to_str(), Style::Level(*level));
1359 label_width += level.to_str().len();
1361 // only render error codes, not lint codes
1362 if let Some(DiagnosticId::Error(ref code)) = *code {
1363 buffer.append(0, "[", Style::Level(*level));
1364 buffer.append(0, &code, Style::Level(*level));
1365 buffer.append(0, "]", Style::Level(*level));
1366 label_width += 2 + code.len();
1368 let header_style = if is_secondary { Style::HeaderMsg } else { Style::MainHeaderMsg };
1369 if *level != Level::FailureNote {
1370 buffer.append(0, ": ", header_style);
1373 for &(ref text, _) in msg.iter() {
1374 let text = self.translate_message(text, args);
1375 // Account for newlines to align output to its label.
1376 for (line, text) in normalize_whitespace(&text).lines().enumerate() {
1381 if line == 0 { String::new() } else { " ".repeat(label_width) },
1389 let mut annotated_files = FileWithAnnotatedLines::collect_annotations(self, args, msp);
1391 // Make sure our primary file comes first
1392 let (primary_lo, sm) = if let (Some(sm), Some(ref primary_span)) =
1393 (self.sm.as_ref(), msp.primary_span().as_ref())
1395 if !primary_span.is_dummy() {
1396 (sm.lookup_char_pos(primary_span.lo()), sm)
1398 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1402 // If we don't have span information, emit and exit
1403 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1407 annotated_files.binary_search_by(|x| x.file.name.cmp(&primary_lo.file.name))
1409 annotated_files.swap(0, pos);
1412 // Print out the annotate source lines that correspond with the error
1413 for annotated_file in annotated_files {
1414 // we can't annotate anything if the source is unavailable.
1415 if !sm.ensure_source_file_source_present(annotated_file.file.clone()) {
1419 // print out the span location and spacer before we print the annotated source
1420 // to do this, we need to know if this span will be primary
1421 let is_primary = primary_lo.file.name == annotated_file.file.name;
1423 let loc = primary_lo.clone();
1424 if !self.short_message {
1425 // remember where we are in the output buffer for easy reference
1426 let buffer_msg_line_offset = buffer.num_lines();
1428 buffer.prepend(buffer_msg_line_offset, "--> ", Style::LineNumber);
1430 buffer_msg_line_offset,
1433 sm.filename_for_diagnostics(&loc.file.name),
1434 sm.doctest_offset_line(&loc.file.name, loc.line),
1437 Style::LineAndColumn,
1439 for _ in 0..max_line_num_len {
1440 buffer.prepend(buffer_msg_line_offset, " ", Style::NoStyle);
1447 sm.filename_for_diagnostics(&loc.file.name),
1448 sm.doctest_offset_line(&loc.file.name, loc.line),
1451 Style::LineAndColumn,
1454 } else if !self.short_message {
1455 // remember where we are in the output buffer for easy reference
1456 let buffer_msg_line_offset = buffer.num_lines();
1459 draw_col_separator_no_space(
1461 buffer_msg_line_offset,
1462 max_line_num_len + 1,
1465 // Then, the secondary file indicator
1466 buffer.prepend(buffer_msg_line_offset + 1, "::: ", Style::LineNumber);
1467 let loc = if let Some(first_line) = annotated_file.lines.first() {
1468 let col = if let Some(first_annotation) = first_line.annotations.first() {
1469 format!(":{}", first_annotation.start_col + 1)
1475 sm.filename_for_diagnostics(&annotated_file.file.name),
1476 sm.doctest_offset_line(&annotated_file.file.name, first_line.line_index),
1480 format!("{}", sm.filename_for_diagnostics(&annotated_file.file.name))
1482 buffer.append(buffer_msg_line_offset + 1, &loc, Style::LineAndColumn);
1483 for _ in 0..max_line_num_len {
1484 buffer.prepend(buffer_msg_line_offset + 1, " ", Style::NoStyle);
1488 if !self.short_message {
1489 // Put in the spacer between the location and annotated source
1490 let buffer_msg_line_offset = buffer.num_lines();
1491 draw_col_separator_no_space(
1493 buffer_msg_line_offset,
1494 max_line_num_len + 1,
1497 // Contains the vertical lines' positions for active multiline annotations
1498 let mut multilines = FxIndexMap::default();
1500 // Get the left-side margin to remove it
1501 let mut whitespace_margin = usize::MAX;
1502 for line_idx in 0..annotated_file.lines.len() {
1503 let file = annotated_file.file.clone();
1504 let line = &annotated_file.lines[line_idx];
1505 if let Some(source_string) = file.get_line(line.line_index - 1) {
1506 let leading_whitespace = source_string
1508 .take_while(|c| c.is_whitespace())
1511 // Tabs are displayed as 4 spaces
1517 if source_string.chars().any(|c| !c.is_whitespace()) {
1518 whitespace_margin = min(whitespace_margin, leading_whitespace);
1522 if whitespace_margin == usize::MAX {
1523 whitespace_margin = 0;
1526 // Left-most column any visible span points at.
1527 let mut span_left_margin = usize::MAX;
1528 for line in &annotated_file.lines {
1529 for ann in &line.annotations {
1530 span_left_margin = min(span_left_margin, ann.start_col);
1531 span_left_margin = min(span_left_margin, ann.end_col);
1534 if span_left_margin == usize::MAX {
1535 span_left_margin = 0;
1538 // Right-most column any visible span points at.
1539 let mut span_right_margin = 0;
1540 let mut label_right_margin = 0;
1541 let mut max_line_len = 0;
1542 for line in &annotated_file.lines {
1545 annotated_file.file.get_line(line.line_index - 1).map_or(0, |s| s.len()),
1547 for ann in &line.annotations {
1548 span_right_margin = max(span_right_margin, ann.start_col);
1549 span_right_margin = max(span_right_margin, ann.end_col);
1550 // FIXME: account for labels not in the same line
1551 let label_right = ann.label.as_ref().map_or(0, |l| l.len() + 1);
1552 label_right_margin = max(label_right_margin, ann.end_col + label_right);
1556 let width_offset = 3 + max_line_num_len;
1557 let code_offset = if annotated_file.multiline_depth == 0 {
1560 width_offset + annotated_file.multiline_depth + 1
1563 let column_width = if let Some(width) = self.diagnostic_width {
1564 width.saturating_sub(code_offset)
1565 } else if self.ui_testing {
1566 DEFAULT_COLUMN_WIDTH
1568 termize::dimensions()
1569 .map(|(w, _)| w.saturating_sub(code_offset))
1570 .unwrap_or(DEFAULT_COLUMN_WIDTH)
1573 let margin = Margin::new(
1582 // Next, output the annotate source for this file
1583 for line_idx in 0..annotated_file.lines.len() {
1584 let previous_buffer_line = buffer.num_lines();
1586 let depths = self.render_source_line(
1588 annotated_file.file.clone(),
1589 &annotated_file.lines[line_idx],
1595 let mut to_add = FxHashMap::default();
1597 for (depth, style) in depths {
1598 if multilines.remove(&depth).is_none() {
1599 to_add.insert(depth, style);
1603 // Set the multiline annotation vertical lines to the left of
1604 // the code in this line.
1605 for (depth, style) in &multilines {
1606 for line in previous_buffer_line..buffer.num_lines() {
1607 draw_multiline_line(&mut buffer, line, width_offset, *depth, *style);
1610 // check to see if we need to print out or elide lines that come between
1611 // this annotated line and the next one.
1612 if line_idx < (annotated_file.lines.len() - 1) {
1613 let line_idx_delta = annotated_file.lines[line_idx + 1].line_index
1614 - annotated_file.lines[line_idx].line_index;
1615 if line_idx_delta > 2 {
1616 let last_buffer_line_num = buffer.num_lines();
1617 buffer.puts(last_buffer_line_num, 0, "...", Style::LineNumber);
1619 // Set the multiline annotation vertical lines on `...` bridging line.
1620 for (depth, style) in &multilines {
1621 draw_multiline_line(
1623 last_buffer_line_num,
1629 } else if line_idx_delta == 2 {
1630 let unannotated_line = annotated_file
1632 .get_line(annotated_file.lines[line_idx].line_index)
1633 .unwrap_or_else(|| Cow::from(""));
1635 let last_buffer_line_num = buffer.num_lines();
1639 &normalize_whitespace(&unannotated_line),
1640 annotated_file.lines[line_idx + 1].line_index - 1,
1641 last_buffer_line_num,
1647 for (depth, style) in &multilines {
1648 draw_multiline_line(
1650 last_buffer_line_num,
1659 multilines.extend(&to_add);
1664 if let Some(tracked) = emitted_at {
1665 let track = format!("-Ztrack-diagnostics: created at {tracked}");
1666 let len = buffer.num_lines();
1667 buffer.append(len, &track, Style::NoStyle);
1670 // final step: take our styled buffer, render it, then output it
1671 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1676 fn emit_suggestion_default(
1679 suggestion: &CodeSuggestion,
1680 args: &FluentArgs<'_>,
1682 max_line_num_len: usize,
1683 ) -> io::Result<()> {
1684 let Some(ref sm) = self.sm else {
1688 // Render the replacements for each suggestion
1689 let suggestions = suggestion.splice_lines(&**sm);
1690 debug!("emit_suggestion_default: suggestions={:?}", suggestions);
1692 if suggestions.is_empty() {
1693 // Suggestions coming from macros can have malformed spans. This is a heavy handed
1694 // approach to avoid ICEs by ignoring the suggestion outright.
1698 let mut buffer = StyledBuffer::new();
1700 // Render the suggestion message
1701 buffer.append(0, level.to_str(), Style::Level(*level));
1702 buffer.append(0, ": ", Style::HeaderMsg);
1706 &[(suggestion.msg.to_owned(), Style::NoStyle)],
1710 Some(Style::HeaderMsg),
1713 let mut row_num = 2;
1714 draw_col_separator_no_space(&mut buffer, 1, max_line_num_len + 1);
1715 let mut notice_capitalization = false;
1716 for (complete, parts, highlights, only_capitalization) in
1717 suggestions.iter().take(MAX_SUGGESTIONS)
1719 notice_capitalization |= only_capitalization;
1721 let has_deletion = parts.iter().any(|p| p.is_deletion(sm));
1722 let is_multiline = complete.lines().count() > 1;
1724 if let Some(span) = span.primary_span() {
1725 // Compare the primary span of the diagnostic with the span of the suggestion
1726 // being emitted. If they belong to the same file, we don't *need* to show the
1727 // file name, saving in verbosity, but if it *isn't* we do need it, otherwise we're
1728 // telling users to make a change but not clarifying *where*.
1729 let loc = sm.lookup_char_pos(parts[0].span.lo());
1730 if loc.file.name != sm.span_to_filename(span) && loc.file.name.is_real() {
1731 buffer.puts(row_num - 1, 0, "--> ", Style::LineNumber);
1736 sm.filename_for_diagnostics(&loc.file.name),
1737 sm.doctest_offset_line(&loc.file.name, loc.line),
1740 Style::LineAndColumn,
1742 for _ in 0..max_line_num_len {
1743 buffer.prepend(row_num - 1, " ", Style::NoStyle);
1748 let show_code_change = if has_deletion && !is_multiline {
1749 DisplaySuggestion::Diff
1750 } else if (parts.len() != 1 || parts[0].snippet.trim() != complete.trim())
1753 DisplaySuggestion::Underline
1755 DisplaySuggestion::None
1758 if let DisplaySuggestion::Diff = show_code_change {
1763 .span_to_lines(parts[0].span)
1764 .expect("span_to_lines failed when emitting suggestion");
1766 assert!(!file_lines.lines.is_empty() || parts[0].span.is_dummy());
1768 let line_start = sm.lookup_char_pos(parts[0].span.lo()).line;
1769 draw_col_separator_no_space(&mut buffer, row_num - 1, max_line_num_len + 1);
1770 let mut lines = complete.lines();
1771 if lines.clone().next().is_none() {
1772 // Account for a suggestion to completely remove a line(s) with whitespace (#94192).
1773 let line_end = sm.lookup_char_pos(parts[0].span.hi()).line;
1774 for line in line_start..=line_end {
1776 row_num - 1 + line - line_start,
1778 &self.maybe_anonymized(line),
1782 row_num - 1 + line - line_start,
1783 max_line_num_len + 1,
1788 row_num - 1 + line - line_start,
1789 max_line_num_len + 3,
1790 &normalize_whitespace(&*file_lines.file.get_line(line - 1).unwrap()),
1794 row_num += line_end - line_start;
1796 let mut unhighlighted_lines = Vec::new();
1797 for (line_pos, (line, highlight_parts)) in lines.by_ref().zip(highlights).enumerate() {
1798 debug!(%line_pos, %line, ?highlight_parts);
1800 // Remember lines that are not highlighted to hide them if needed
1801 if highlight_parts.is_empty() {
1802 unhighlighted_lines.push((line_pos, line));
1806 match unhighlighted_lines.len() {
1808 // Since we show first line, "..." line and last line,
1809 // There is no reason to hide if there are 3 or less lines
1810 // (because then we just replace a line with ... which is
1812 n if n <= 3 => unhighlighted_lines.drain(..).for_each(|(p, l)| {
1813 self.draw_code_line(
1826 // Print first unhighlighted line, "..." and last unhighlighted line, like so:
1828 // LL | this line was highlighted
1829 // LL | this line is just for context
1831 // LL | this line is just for context
1832 // LL | this line was highlighted
1834 let last_line = unhighlighted_lines.pop();
1835 let first_line = unhighlighted_lines.drain(..).next();
1837 first_line.map(|(p, l)| {
1838 self.draw_code_line(
1852 buffer.puts(row_num, max_line_num_len - 1, "...", Style::LineNumber);
1855 last_line.map(|(p, l)| {
1856 self.draw_code_line(
1872 self.draw_code_line(
1886 // This offset and the ones below need to be signed to account for replacement code
1887 // that is shorter than the original code.
1888 let mut offsets: Vec<(usize, isize)> = Vec::new();
1889 // Only show an underline in the suggestions if the suggestion is not the
1890 // entirety of the code being shown and the displayed code is not multiline.
1891 if let DisplaySuggestion::Diff | DisplaySuggestion::Underline = show_code_change {
1892 draw_col_separator_no_space(&mut buffer, row_num, max_line_num_len + 1);
1894 let span_start_pos = sm.lookup_char_pos(part.span.lo()).col_display;
1895 let span_end_pos = sm.lookup_char_pos(part.span.hi()).col_display;
1897 // If this addition is _only_ whitespace, then don't trim it,
1898 // or else we're just not rendering anything.
1899 let is_whitespace_addition = part.snippet.trim().is_empty();
1901 // Do not underline the leading...
1902 let start = if is_whitespace_addition {
1905 part.snippet.len().saturating_sub(part.snippet.trim_start().len())
1907 // ...or trailing spaces. Account for substitutions containing unicode
1909 let sub_len: usize =
1910 if is_whitespace_addition { &part.snippet } else { part.snippet.trim() }
1912 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
1915 let offset: isize = offsets
1918 |(start, v)| if span_start_pos <= *start { None } else { Some(v) },
1921 let underline_start = (span_start_pos + start) as isize + offset;
1922 let underline_end = (span_start_pos + start + sub_len) as isize + offset;
1923 assert!(underline_start >= 0 && underline_end >= 0);
1924 let padding: usize = max_line_num_len + 3;
1925 for p in underline_start..underline_end {
1926 if let DisplaySuggestion::Underline = show_code_change {
1927 // If this is a replacement, underline with `^`, if this is an addition
1928 // underline with `+`.
1931 (padding as isize + p) as usize,
1932 if part.is_addition(&sm) { '+' } else { '~' },
1937 if let DisplaySuggestion::Diff = show_code_change {
1938 // Colorize removal with red in diff format.
1939 buffer.set_style_range(
1941 (padding as isize + span_start_pos as isize) as usize,
1942 (padding as isize + span_end_pos as isize) as usize,
1948 // length of the code after substitution
1949 let full_sub_len = part
1952 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
1953 .sum::<usize>() as isize;
1955 // length of the code to be substituted
1956 let snippet_len = span_end_pos as isize - span_start_pos as isize;
1957 // For multiple substitutions, use the position *after* the previous
1958 // substitutions have happened, only when further substitutions are
1959 // located strictly after.
1960 offsets.push((span_end_pos, full_sub_len - snippet_len));
1965 // if we elided some lines, add an ellipsis
1966 if lines.next().is_some() {
1967 buffer.puts(row_num, max_line_num_len - 1, "...", Style::LineNumber);
1968 } else if let DisplaySuggestion::None = show_code_change {
1969 draw_col_separator_no_space(&mut buffer, row_num, max_line_num_len + 1);
1973 if suggestions.len() > MAX_SUGGESTIONS {
1974 let others = suggestions.len() - MAX_SUGGESTIONS;
1975 let msg = format!("and {} other candidate{}", others, pluralize!(others));
1976 buffer.puts(row_num, max_line_num_len + 3, &msg, Style::NoStyle);
1977 } else if notice_capitalization {
1978 let msg = "notice the capitalization difference";
1979 buffer.puts(row_num, max_line_num_len + 3, &msg, Style::NoStyle);
1981 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1985 fn emit_messages_default(
1988 message: &[(DiagnosticMessage, Style)],
1989 args: &FluentArgs<'_>,
1990 code: &Option<DiagnosticId>,
1992 children: &[SubDiagnostic],
1993 suggestions: &[CodeSuggestion],
1994 emitted_at: Option<&DiagnosticLocation>,
1996 let max_line_num_len = if self.ui_testing {
1997 ANONYMIZED_LINE_NUM.len()
1999 let n = self.get_max_line_num(span, children);
2000 num_decimal_digits(n)
2003 match self.emit_message_default(
2014 if !children.is_empty()
2015 || suggestions.iter().any(|s| s.style != SuggestionStyle::CompletelyHidden)
2017 let mut buffer = StyledBuffer::new();
2018 if !self.short_message {
2019 draw_col_separator_no_space(&mut buffer, 0, max_line_num_len + 1);
2021 if let Err(e) = emit_to_destination(
2027 panic!("failed to emit error: {}", e)
2030 if !self.short_message {
2031 for child in children {
2032 let span = child.render_span.as_ref().unwrap_or(&child.span);
2033 if let Err(err) = self.emit_message_default(
2043 panic!("failed to emit error: {}", err);
2046 for sugg in suggestions {
2047 if sugg.style == SuggestionStyle::CompletelyHidden {
2048 // do not display this suggestion, it is meant only for tools
2049 } else if sugg.style == SuggestionStyle::HideCodeAlways {
2050 if let Err(e) = self.emit_message_default(
2052 &[(sugg.msg.to_owned(), Style::HeaderMsg)],
2060 panic!("failed to emit error: {}", e);
2062 } else if let Err(e) = self.emit_suggestion_default(
2069 panic!("failed to emit error: {}", e);
2074 Err(e) => panic!("failed to emit error: {}", e),
2077 let mut dst = self.dst.writable();
2078 match writeln!(dst) {
2079 Err(e) => panic!("failed to emit error: {}", e),
2081 if let Err(e) = dst.flush() {
2082 panic!("failed to emit error: {}", e)
2090 buffer: &mut StyledBuffer,
2091 row_num: &mut usize,
2092 highlight_parts: &Vec<SubstitutionHighlight>,
2096 show_code_change: DisplaySuggestion,
2097 max_line_num_len: usize,
2098 file_lines: &FileLines,
2101 // Print the span column to avoid confusion
2102 buffer.puts(*row_num, 0, &self.maybe_anonymized(line_start + line_pos), Style::LineNumber);
2103 if let DisplaySuggestion::Diff = show_code_change {
2104 // Add the line number for both addition and removal to drive the point home.
2106 // N - fn foo<A: T>(bar: A) {
2107 // N + fn foo(bar: impl T) {
2111 &self.maybe_anonymized(line_start + line_pos),
2114 buffer.puts(*row_num - 1, max_line_num_len + 1, "- ", Style::Removal);
2117 max_line_num_len + 3,
2118 &normalize_whitespace(
2119 &*file_lines.file.get_line(file_lines.lines[line_pos].line_index).unwrap(),
2123 buffer.puts(*row_num, max_line_num_len + 1, "+ ", Style::Addition);
2124 } else if is_multiline {
2125 match &highlight_parts[..] {
2126 [SubstitutionHighlight { start: 0, end }] if *end == line.len() => {
2127 buffer.puts(*row_num, max_line_num_len + 1, "+ ", Style::Addition);
2130 draw_col_separator(buffer, *row_num, max_line_num_len + 1);
2133 buffer.puts(*row_num, max_line_num_len + 1, "~ ", Style::Addition);
2137 draw_col_separator(buffer, *row_num, max_line_num_len + 1);
2140 // print the suggestion
2141 buffer.append(*row_num, &normalize_whitespace(line), Style::NoStyle);
2143 // Colorize addition/replacements with green.
2144 for &SubstitutionHighlight { start, end } in highlight_parts {
2145 // Account for tabs when highlighting (#87972).
2146 let tabs: usize = line
2149 .map(|ch| match ch {
2154 buffer.set_style_range(
2156 max_line_num_len + 3 + start + tabs,
2157 max_line_num_len + 3 + end + tabs,
2166 #[derive(Clone, Copy, Debug)]
2167 enum DisplaySuggestion {
2173 impl FileWithAnnotatedLines {
2174 /// Preprocess all the annotations so that they are grouped by file and by line number
2175 /// This helps us quickly iterate over the whole message (including secondary file spans)
2176 pub fn collect_annotations(
2177 emitter: &dyn Emitter,
2178 args: &FluentArgs<'_>,
2180 ) -> Vec<FileWithAnnotatedLines> {
2181 fn add_annotation_to_file(
2182 file_vec: &mut Vec<FileWithAnnotatedLines>,
2183 file: Lrc<SourceFile>,
2187 for slot in file_vec.iter_mut() {
2188 // Look through each of our files for the one we're adding to
2189 if slot.file.name == file.name {
2190 // See if we already have a line for it
2191 for line_slot in &mut slot.lines {
2192 if line_slot.line_index == line_index {
2193 line_slot.annotations.push(ann);
2197 // We don't have a line yet, create one
2198 slot.lines.push(Line { line_index, annotations: vec![ann] });
2203 // This is the first time we're seeing the file
2204 file_vec.push(FileWithAnnotatedLines {
2206 lines: vec![Line { line_index, annotations: vec![ann] }],
2211 let mut output = vec![];
2212 let mut multiline_annotations = vec![];
2214 if let Some(ref sm) = emitter.source_map() {
2215 for span_label in msp.span_labels() {
2216 if span_label.span.is_dummy() {
2220 let lo = sm.lookup_char_pos(span_label.span.lo());
2221 let mut hi = sm.lookup_char_pos(span_label.span.hi());
2223 // Watch out for "empty spans". If we get a span like 6..6, we
2224 // want to just display a `^` at 6, so convert that to
2225 // 6..7. This is degenerate input, but it's best to degrade
2226 // gracefully -- and the parser likes to supply a span like
2227 // that for EOF, in particular.
2229 if lo.col_display == hi.col_display && lo.line == hi.line {
2230 hi.col_display += 1;
2233 if lo.line != hi.line {
2234 let ml = MultilineAnnotation {
2236 line_start: lo.line,
2238 start_col: lo.col_display,
2239 end_col: hi.col_display,
2240 is_primary: span_label.is_primary,
2244 .map(|m| emitter.translate_message(m, args).to_string()),
2245 overlaps_exactly: false,
2247 multiline_annotations.push((lo.file, ml));
2249 let ann = Annotation {
2250 start_col: lo.col_display,
2251 end_col: hi.col_display,
2252 is_primary: span_label.is_primary,
2256 .map(|m| emitter.translate_message(m, args).to_string()),
2257 annotation_type: AnnotationType::Singleline,
2259 add_annotation_to_file(&mut output, lo.file, lo.line, ann);
2264 // Find overlapping multiline annotations, put them at different depths
2265 multiline_annotations.sort_by_key(|&(_, ref ml)| (ml.line_start, ml.line_end));
2266 for (_, ann) in multiline_annotations.clone() {
2267 for (_, a) in multiline_annotations.iter_mut() {
2268 // Move all other multiline annotations overlapping with this one
2269 // one level to the right.
2270 if !(ann.same_span(a))
2271 && num_overlap(ann.line_start, ann.line_end, a.line_start, a.line_end, true)
2274 } else if ann.same_span(a) && &ann != a {
2275 a.overlaps_exactly = true;
2282 let mut max_depth = 0; // max overlapping multiline spans
2283 for (file, ann) in multiline_annotations {
2284 max_depth = max(max_depth, ann.depth);
2285 let mut end_ann = ann.as_end();
2286 if !ann.overlaps_exactly {
2287 // avoid output like
2309 add_annotation_to_file(&mut output, file.clone(), ann.line_start, ann.as_start());
2310 // 4 is the minimum vertical length of a multiline span when presented: two lines
2311 // of code and two lines of underline. This is not true for the special case where
2312 // the beginning doesn't have an underline, but the current logic seems to be
2313 // working correctly.
2314 let middle = min(ann.line_start + 4, ann.line_end);
2315 for line in ann.line_start + 1..middle {
2316 // Every `|` that joins the beginning of the span (`___^`) to the end (`|__^`).
2317 add_annotation_to_file(&mut output, file.clone(), line, ann.as_line());
2319 let line_end = ann.line_end - 1;
2320 if middle < line_end {
2321 add_annotation_to_file(&mut output, file.clone(), line_end, ann.as_line());
2324 end_ann.annotation_type = AnnotationType::Singleline;
2326 add_annotation_to_file(&mut output, file, ann.line_end, end_ann);
2328 for file_vec in output.iter_mut() {
2329 file_vec.multiline_depth = max_depth;
2335 // instead of taking the String length or dividing by 10 while > 0, we multiply a limit by 10 until
2336 // we're higher. If the loop isn't exited by the `return`, the last multiplication will wrap, which
2337 // is OK, because while we cannot fit a higher power of 10 in a usize, the loop will end anyway.
2338 // This is also why we need the max number of decimal digits within a `usize`.
2339 fn num_decimal_digits(num: usize) -> usize {
2340 #[cfg(target_pointer_width = "64")]
2341 const MAX_DIGITS: usize = 20;
2343 #[cfg(target_pointer_width = "32")]
2344 const MAX_DIGITS: usize = 10;
2346 #[cfg(target_pointer_width = "16")]
2347 const MAX_DIGITS: usize = 5;
2350 for num_digits in 1..MAX_DIGITS {
2354 lim = lim.wrapping_mul(10);
2359 // We replace some characters so the CLI output is always consistent and underlines aligned.
2360 const OUTPUT_REPLACEMENTS: &[(char, &str)] = &[
2361 ('\t', " "), // We do our own tab replacement
2362 ('\u{200D}', ""), // Replace ZWJ with nothing for consistent terminal output of grapheme clusters.
2363 ('\u{202A}', ""), // The following unicode text flow control characters are inconsistently
2364 ('\u{202B}', ""), // supported across CLIs and can cause confusion due to the bytes on disk
2365 ('\u{202D}', ""), // not corresponding to the visible source code, so we replace them always.
2374 fn normalize_whitespace(str: &str) -> String {
2375 let mut s = str.to_string();
2376 for (c, replacement) in OUTPUT_REPLACEMENTS {
2377 s = s.replace(*c, replacement);
2382 fn draw_col_separator(buffer: &mut StyledBuffer, line: usize, col: usize) {
2383 buffer.puts(line, col, "| ", Style::LineNumber);
2386 fn draw_col_separator_no_space(buffer: &mut StyledBuffer, line: usize, col: usize) {
2387 draw_col_separator_no_space_with_style(buffer, line, col, Style::LineNumber);
2390 fn draw_col_separator_no_space_with_style(
2391 buffer: &mut StyledBuffer,
2396 buffer.putc(line, col, '|', style);
2400 buffer: &mut StyledBuffer,
2407 for col in col_from..col_to {
2408 buffer.putc(line, col, symbol, style);
2412 fn draw_note_separator(buffer: &mut StyledBuffer, line: usize, col: usize) {
2413 buffer.puts(line, col, "= ", Style::LineNumber);
2416 fn draw_multiline_line(
2417 buffer: &mut StyledBuffer,
2423 buffer.putc(line, offset + depth - 1, '|', style);
2433 let extra = if inclusive { 1 } else { 0 };
2434 (b_start..b_end + extra).contains(&a_start) || (a_start..a_end + extra).contains(&b_start)
2436 fn overlaps(a1: &Annotation, a2: &Annotation, padding: usize) -> bool {
2437 num_overlap(a1.start_col, a1.end_col + padding, a2.start_col, a2.end_col, false)
2440 fn emit_to_destination(
2441 rendered_buffer: &[Vec<StyledString>],
2443 dst: &mut Destination,
2444 short_message: bool,
2445 ) -> io::Result<()> {
2448 let mut dst = dst.writable();
2450 // In order to prevent error message interleaving, where multiple error lines get intermixed
2451 // when multiple compiler processes error simultaneously, we emit errors with additional
2454 // On Unix systems, we write into a buffered terminal rather than directly to a terminal. When
2455 // the .flush() is called we take the buffer created from the buffered writes and write it at
2456 // one shot. Because the Unix systems use ANSI for the colors, which is a text-based styling
2457 // scheme, this buffered approach works and maintains the styling.
2459 // On Windows, styling happens through calls to a terminal API. This prevents us from using the
2460 // same buffering approach. Instead, we use a global Windows mutex, which we acquire long
2461 // enough to output the full error message, then we release.
2462 let _buffer_lock = lock::acquire_global_lock("rustc_errors");
2463 for (pos, line) in rendered_buffer.iter().enumerate() {
2465 dst.apply_style(*lvl, part.style)?;
2466 write!(dst, "{}", part.text)?;
2469 if !short_message && (!lvl.is_failure_note() || pos != rendered_buffer.len() - 1) {
2477 pub enum Destination {
2478 Terminal(StandardStream),
2479 Buffered(BufferWriter),
2480 // The bool denotes whether we should be emitting ansi color codes or not
2481 Raw(Box<(dyn Write + Send)>, bool),
2484 pub enum WritableDst<'a> {
2485 Terminal(&'a mut StandardStream),
2486 Buffered(&'a mut BufferWriter, Buffer),
2487 Raw(&'a mut (dyn Write + Send)),
2488 ColoredRaw(Ansi<&'a mut (dyn Write + Send)>),
2492 fn from_stderr(color: ColorConfig) -> Destination {
2493 let choice = color.to_color_choice();
2494 // On Windows we'll be performing global synchronization on the entire
2495 // system for emitting rustc errors, so there's no need to buffer
2498 // On non-Windows we rely on the atomicity of `write` to ensure errors
2499 // don't get all jumbled up.
2501 Terminal(StandardStream::stderr(choice))
2503 Buffered(BufferWriter::stderr(choice))
2507 fn writable(&mut self) -> WritableDst<'_> {
2509 Destination::Terminal(ref mut t) => WritableDst::Terminal(t),
2510 Destination::Buffered(ref mut t) => {
2511 let buf = t.buffer();
2512 WritableDst::Buffered(t, buf)
2514 Destination::Raw(ref mut t, false) => WritableDst::Raw(t),
2515 Destination::Raw(ref mut t, true) => WritableDst::ColoredRaw(Ansi::new(t)),
2519 fn supports_color(&self) -> bool {
2521 Self::Terminal(ref stream) => stream.supports_color(),
2522 Self::Buffered(ref buffer) => buffer.buffer().supports_color(),
2523 Self::Raw(_, supports_color) => supports_color,
2528 impl<'a> WritableDst<'a> {
2529 fn apply_style(&mut self, lvl: Level, style: Style) -> io::Result<()> {
2530 let mut spec = ColorSpec::new();
2532 Style::Addition => {
2533 spec.set_fg(Some(Color::Green)).set_intense(true);
2536 spec.set_fg(Some(Color::Red)).set_intense(true);
2538 Style::LineAndColumn => {}
2539 Style::LineNumber => {
2540 spec.set_bold(true);
2541 spec.set_intense(true);
2543 spec.set_fg(Some(Color::Cyan));
2545 spec.set_fg(Some(Color::Blue));
2548 Style::Quotation => {}
2549 Style::MainHeaderMsg => {
2550 spec.set_bold(true);
2552 spec.set_intense(true).set_fg(Some(Color::White));
2555 Style::UnderlinePrimary | Style::LabelPrimary => {
2557 spec.set_bold(true);
2559 Style::UnderlineSecondary | Style::LabelSecondary => {
2560 spec.set_bold(true).set_intense(true);
2562 spec.set_fg(Some(Color::Cyan));
2564 spec.set_fg(Some(Color::Blue));
2567 Style::HeaderMsg | Style::NoStyle => {}
2568 Style::Level(lvl) => {
2570 spec.set_bold(true);
2572 Style::Highlight => {
2573 spec.set_bold(true);
2576 self.set_color(&spec)
2579 fn set_color(&mut self, color: &ColorSpec) -> io::Result<()> {
2581 WritableDst::Terminal(ref mut t) => t.set_color(color),
2582 WritableDst::Buffered(_, ref mut t) => t.set_color(color),
2583 WritableDst::ColoredRaw(ref mut t) => t.set_color(color),
2584 WritableDst::Raw(_) => Ok(()),
2588 fn reset(&mut self) -> io::Result<()> {
2590 WritableDst::Terminal(ref mut t) => t.reset(),
2591 WritableDst::Buffered(_, ref mut t) => t.reset(),
2592 WritableDst::ColoredRaw(ref mut t) => t.reset(),
2593 WritableDst::Raw(_) => Ok(()),
2598 impl<'a> Write for WritableDst<'a> {
2599 fn write(&mut self, bytes: &[u8]) -> io::Result<usize> {
2601 WritableDst::Terminal(ref mut t) => t.write(bytes),
2602 WritableDst::Buffered(_, ref mut buf) => buf.write(bytes),
2603 WritableDst::Raw(ref mut w) => w.write(bytes),
2604 WritableDst::ColoredRaw(ref mut t) => t.write(bytes),
2608 fn flush(&mut self) -> io::Result<()> {
2610 WritableDst::Terminal(ref mut t) => t.flush(),
2611 WritableDst::Buffered(_, ref mut buf) => buf.flush(),
2612 WritableDst::Raw(ref mut w) => w.flush(),
2613 WritableDst::ColoredRaw(ref mut w) => w.flush(),
2618 impl<'a> Drop for WritableDst<'a> {
2619 fn drop(&mut self) {
2620 if let WritableDst::Buffered(ref mut dst, ref mut buf) = self {
2621 drop(dst.print(buf));
2626 /// Whether the original and suggested code are visually similar enough to warrant extra wording.
2627 pub fn is_case_difference(sm: &SourceMap, suggested: &str, sp: Span) -> bool {
2628 // FIXME: this should probably be extended to also account for `FO0` → `FOO` and unicode.
2629 let found = match sm.span_to_snippet(sp) {
2630 Ok(snippet) => snippet,
2632 warn!(error = ?e, "Invalid span {:?}", sp);
2636 let ascii_confusables = &['c', 'f', 'i', 'k', 'o', 's', 'u', 'v', 'w', 'x', 'y', 'z'];
2637 // All the chars that differ in capitalization are confusable (above):
2638 let confusable = iter::zip(found.chars(), suggested.chars())
2639 .filter(|(f, s)| f != s)
2640 .all(|(f, s)| (ascii_confusables.contains(&f) || ascii_confusables.contains(&s)));
2641 confusable && found.to_lowercase() == suggested.to_lowercase()
2642 // FIXME: We sometimes suggest the same thing we already have, which is a
2643 // bug, but be defensive against that here.
2644 && found != suggested