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, SpanLabel};
28 use rustc_span::hygiene::{ExpnKind, MacroKind};
30 use std::cmp::{max, min, Reverse};
31 use std::io::prelude::*;
32 use std::io::{self, IsTerminal};
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_deref().unwrap_or(&[]);
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 span: &mut MultiSpan,
318 children: &mut Vec<SubDiagnostic>,
322 // Check for spans in macros, before `fix_multispans_in_extern_macros`
323 // has a chance to replace them.
324 let has_macro_spans: Vec<_> = iter::once(&*span)
325 .chain(children.iter().map(|child| &child.span))
326 .flat_map(|span| span.primary_spans())
327 .flat_map(|sp| sp.macro_backtrace())
328 .filter_map(|expn_data| {
329 match expn_data.kind {
330 ExpnKind::Root => None,
332 // Skip past non-macro entries, just in case there
333 // are some which do actually involve macros.
334 ExpnKind::Inlined | ExpnKind::Desugaring(..) | ExpnKind::AstPass(..) => None,
336 ExpnKind::Macro(macro_kind, name) => Some((macro_kind, name)),
342 self.fix_multispans_in_extern_macros(span, children);
345 self.render_multispans_macro_backtrace(span, children, backtrace);
348 if let Some((macro_kind, name)) = has_macro_spans.first() {
349 // Mark the actual macro this originates from
350 let and_then = if let Some((macro_kind, last_name)) = has_macro_spans.last()
353 let descr = macro_kind.descr();
355 " which comes from the expansion of the {descr} `{last_name}`",
361 let descr = macro_kind.descr();
363 "this {level} originates in the {descr} `{name}`{and_then} \
364 (in Nightly builds, run with -Z macro-backtrace for more info)",
367 children.push(SubDiagnostic {
369 message: vec![(DiagnosticMessage::Str(msg), Style::NoStyle)],
370 span: MultiSpan::new(),
377 fn render_multispans_macro_backtrace(
379 span: &mut MultiSpan,
380 children: &mut Vec<SubDiagnostic>,
383 for span in iter::once(span).chain(children.iter_mut().map(|child| &mut child.span)) {
384 self.render_multispan_macro_backtrace(span, backtrace);
388 fn render_multispan_macro_backtrace(&self, span: &mut MultiSpan, always_backtrace: bool) {
389 let mut new_labels: Vec<(Span, String)> = vec![];
391 for &sp in span.primary_spans() {
396 // FIXME(eddyb) use `retain` on `macro_backtrace` to remove all the
397 // entries we don't want to print, to make sure the indices being
398 // printed are contiguous (or omitted if there's only one entry).
399 let macro_backtrace: Vec<_> = sp.macro_backtrace().collect();
400 for (i, trace) in macro_backtrace.iter().rev().enumerate() {
401 if trace.def_site.is_dummy() {
405 if always_backtrace && !matches!(trace.kind, ExpnKind::Inlined) {
409 "in this expansion of `{}`{}",
411 if macro_backtrace.len() > 1 {
412 // if macro_backtrace.len() == 1 it'll be
413 // pointed at by "in this macro invocation"
414 format!(" (#{})", i + 1)
422 // Don't add a label on the call site if the diagnostic itself
423 // already points to (a part of) that call site, as the label
424 // is meant for showing the relevant invocation when the actual
425 // diagnostic is pointing to some part of macro definition.
427 // This also handles the case where an external span got replaced
428 // with the call site span by `fix_multispans_in_extern_macros`.
430 // NB: `-Zmacro-backtrace` overrides this, for uniformity, as the
431 // "in this expansion of" label above is always added in that mode,
432 // and it needs an "in this macro invocation" label to match that.
433 let redundant_span = trace.call_site.contains(sp);
435 if !redundant_span || always_backtrace {
436 let msg: Cow<'static, _> = match trace.kind {
437 ExpnKind::Macro(MacroKind::Attr, _) => {
438 "this procedural macro expansion".into()
440 ExpnKind::Macro(MacroKind::Derive, _) => {
441 "this derive macro expansion".into()
443 ExpnKind::Macro(MacroKind::Bang, _) => "this macro invocation".into(),
444 ExpnKind::Inlined => "this inlined function call".into(),
445 ExpnKind::Root => "the crate root".into(),
446 ExpnKind::AstPass(kind) => kind.descr().into(),
447 ExpnKind::Desugaring(kind) => {
448 format!("this {} desugaring", kind.descr()).into()
456 if macro_backtrace.len() > 1 && always_backtrace {
457 // only specify order when the macro
458 // backtrace is multiple levels deep
459 format!(" (#{})", i + 1)
466 if !always_backtrace {
472 for (label_span, label_text) in new_labels {
473 span.push_span_label(label_span, label_text);
477 // This does a small "fix" for multispans by looking to see if it can find any that
478 // point directly at external macros. Since these are often difficult to read,
479 // this will change the span to point at the use site.
480 fn fix_multispans_in_extern_macros(
482 span: &mut MultiSpan,
483 children: &mut Vec<SubDiagnostic>,
485 debug!("fix_multispans_in_extern_macros: before: span={:?} children={:?}", span, children);
486 self.fix_multispan_in_extern_macros(span);
487 for child in children.iter_mut() {
488 self.fix_multispan_in_extern_macros(&mut child.span);
490 debug!("fix_multispans_in_extern_macros: after: span={:?} children={:?}", span, children);
493 // This "fixes" MultiSpans that contain `Span`s pointing to locations inside of external macros.
494 // Since these locations are often difficult to read,
495 // we move these spans from the external macros to their corresponding use site.
496 fn fix_multispan_in_extern_macros(&self, span: &mut MultiSpan) {
497 let Some(source_map) = self.source_map() else { return };
498 // First, find all the spans in external macros and point instead at their use site.
499 let replacements: Vec<(Span, Span)> = span
503 .chain(span.span_labels().iter().map(|sp_label| sp_label.span))
505 if !sp.is_dummy() && source_map.is_imported(sp) {
506 let maybe_callsite = sp.source_callsite();
507 if sp != maybe_callsite {
508 return Some((sp, maybe_callsite));
515 // After we have them, make sure we replace these 'bad' def sites with their use sites.
516 for (from, to) in replacements {
517 span.replace(from, to);
522 impl Translate for EmitterWriter {
523 fn fluent_bundle(&self) -> Option<&Lrc<FluentBundle>> {
524 self.fluent_bundle.as_ref()
527 fn fallback_fluent_bundle(&self) -> &FluentBundle {
528 &self.fallback_bundle
532 impl Emitter for EmitterWriter {
533 fn source_map(&self) -> Option<&Lrc<SourceMap>> {
537 fn emit_diagnostic(&mut self, diag: &Diagnostic) {
538 let fluent_args = to_fluent_args(diag.args());
540 let mut children = diag.children.clone();
541 let (mut primary_span, suggestions) = self.primary_span_formatted(diag, &fluent_args);
542 debug!("emit_diagnostic: suggestions={:?}", suggestions);
544 self.fix_multispans_in_extern_macros_and_render_macro_backtrace(
548 self.macro_backtrace,
551 self.emit_messages_default(
559 self.track_diagnostics.then_some(&diag.emitted_at),
563 fn should_show_explain(&self) -> bool {
567 fn supports_color(&self) -> bool {
568 self.dst.supports_color()
572 /// An emitter that does nothing when emitting a non-fatal diagnostic.
573 /// Fatal diagnostics are forwarded to `fatal_handler` to avoid silent
574 /// failures of rustc, as witnessed e.g. in issue #89358.
575 pub struct SilentEmitter {
576 pub fatal_handler: Handler,
577 pub fatal_note: Option<String>,
580 impl Translate for SilentEmitter {
581 fn fluent_bundle(&self) -> Option<&Lrc<FluentBundle>> {
585 fn fallback_fluent_bundle(&self) -> &FluentBundle {
586 panic!("silent emitter attempted to translate message")
590 impl Emitter for SilentEmitter {
591 fn source_map(&self) -> Option<&Lrc<SourceMap>> {
595 fn emit_diagnostic(&mut self, d: &Diagnostic) {
596 if d.level == Level::Fatal {
597 let mut d = d.clone();
598 if let Some(ref note) = self.fatal_note {
601 self.fatal_handler.emit_diagnostic(&mut d);
606 /// Maximum number of suggestions to be shown
608 /// Arbitrary, but taken from trait import suggestion limit
609 pub const MAX_SUGGESTIONS: usize = 4;
611 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
612 pub enum ColorConfig {
619 fn to_color_choice(self) -> ColorChoice {
621 ColorConfig::Always => {
622 if io::stderr().is_terminal() {
625 ColorChoice::AlwaysAnsi
628 ColorConfig::Never => ColorChoice::Never,
629 ColorConfig::Auto if io::stderr().is_terminal() => ColorChoice::Auto,
630 ColorConfig::Auto => ColorChoice::Never,
633 fn suggests_using_colors(self) -> bool {
635 ColorConfig::Always | ColorConfig::Auto => true,
636 ColorConfig::Never => false,
641 /// Handles the writing of `HumanReadableErrorType::Default` and `HumanReadableErrorType::Short`
642 pub struct EmitterWriter {
644 sm: Option<Lrc<SourceMap>>,
645 fluent_bundle: Option<Lrc<FluentBundle>>,
646 fallback_bundle: LazyFallbackBundle,
650 diagnostic_width: Option<usize>,
652 macro_backtrace: bool,
653 track_diagnostics: bool,
657 pub struct FileWithAnnotatedLines {
658 pub file: Lrc<SourceFile>,
659 pub lines: Vec<Line>,
660 multiline_depth: usize,
665 color_config: ColorConfig,
666 source_map: Option<Lrc<SourceMap>>,
667 fluent_bundle: Option<Lrc<FluentBundle>>,
668 fallback_bundle: LazyFallbackBundle,
671 diagnostic_width: Option<usize>,
672 macro_backtrace: bool,
673 track_diagnostics: bool,
675 let dst = Destination::from_stderr(color_config);
691 dst: Box<dyn Write + Send>,
692 source_map: Option<Lrc<SourceMap>>,
693 fluent_bundle: Option<Lrc<FluentBundle>>,
694 fallback_bundle: LazyFallbackBundle,
698 diagnostic_width: Option<usize>,
699 macro_backtrace: bool,
700 track_diagnostics: bool,
703 dst: Raw(dst, colored),
716 pub fn ui_testing(mut self, ui_testing: bool) -> Self {
717 self.ui_testing = ui_testing;
721 fn maybe_anonymized(&self, line_num: usize) -> Cow<'static, str> {
723 Cow::Borrowed(ANONYMIZED_LINE_NUM)
725 Cow::Owned(line_num.to_string())
731 buffer: &mut StyledBuffer,
739 // Tabs are assumed to have been replaced by spaces in calling code.
740 debug_assert!(!source_string.contains('\t'));
741 let line_len = source_string.len();
742 // Create the source line we will highlight.
743 let left = margin.left(line_len);
744 let right = margin.right(line_len);
745 // On long lines, we strip the source line, accounting for unicode.
747 let code: String = source_string
751 // Make sure that the trimming on the right will fall within the terminal width.
752 // FIXME: `unicode_width` sometimes disagrees with terminals on how wide a `char` is.
753 // For now, just accept that sometimes the code line will be longer than desired.
754 let next = unicode_width::UnicodeWidthChar::width(*ch).unwrap_or(1);
755 if taken + next > right - left {
762 buffer.puts(line_offset, code_offset, &code, Style::Quotation);
763 if margin.was_cut_left() {
764 // We have stripped some code/whitespace from the beginning, make it clear.
765 buffer.puts(line_offset, code_offset, "...", Style::LineNumber);
767 if margin.was_cut_right(line_len) {
768 // We have stripped some code after the right-most span end, make it clear we did so.
769 buffer.puts(line_offset, code_offset + taken - 3, "...", Style::LineNumber);
771 buffer.puts(line_offset, 0, &self.maybe_anonymized(line_index), Style::LineNumber);
773 draw_col_separator_no_space(buffer, line_offset, width_offset - 2);
776 #[instrument(level = "trace", skip(self), ret)]
777 fn render_source_line(
779 buffer: &mut StyledBuffer,
780 file: Lrc<SourceFile>,
785 ) -> Vec<(usize, Style)> {
791 // | secondary span label
793 // ^^ ^ ^^^ ^^^^ ^^^ we don't care about code too far to the right of a span, we trim it
795 // | | | actual code found in your source code and the spans we use to mark it
796 // | | when there's too much wasted space to the left, trim it
797 // | vertical divider between the column number and the code
800 if line.line_index == 0 {
804 let source_string = match file.get_line(line.line_index - 1) {
805 Some(s) => normalize_whitespace(&s),
806 None => return Vec::new(),
808 trace!(?source_string);
810 let line_offset = buffer.num_lines();
813 let left = margin.left(source_string.len());
815 // Account for unicode characters of width !=0 that were removed.
816 let left = source_string
819 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
832 // Special case when there's only one annotation involved, it is the start of a multiline
833 // span and there's no text at the beginning of the code line. Instead of doing the whole
842 // we simplify the output to:
848 if let [ann] = &line.annotations[..] {
849 if let AnnotationType::MultilineStart(depth) = ann.annotation_type {
850 if source_string.chars().take(ann.start_col).all(|c| c.is_whitespace()) {
851 let style = if ann.is_primary {
852 Style::UnderlinePrimary
854 Style::UnderlineSecondary
856 buffer.putc(line_offset, width_offset + depth - 1, '/', style);
857 return vec![(depth, style)];
862 // We want to display like this:
864 // vec.push(vec.pop().unwrap());
865 // --- ^^^ - previous borrow ends here
867 // | error occurs here
868 // previous borrow of `vec` occurs here
870 // But there are some weird edge cases to be aware of:
872 // vec.push(vec.pop().unwrap());
873 // -------- - previous borrow ends here
875 // |this makes no sense
876 // previous borrow of `vec` occurs here
878 // For this reason, we group the lines into "highlight lines"
879 // and "annotations lines", where the highlight lines have the `^`.
881 // Sort the annotations by (start, end col)
882 // The labels are reversed, sort and then reversed again.
883 // Consider a list of annotations (A1, A2, C1, C2, B1, B2) where
884 // the letter signifies the span. Here we are only sorting by the
885 // span and hence, the order of the elements with the same span will
886 // not change. On reversing the ordering (|a, b| but b.cmp(a)), you get
887 // (C1, C2, B1, B2, A1, A2). All the elements with the same span are
888 // still ordered first to last, but all the elements with different
889 // spans are ordered by their spans in last to first order. Last to
890 // first order is important, because the jiggly lines and | are on
891 // the left, so the rightmost span needs to be rendered first,
892 // otherwise the lines would end up needing to go over a message.
894 let mut annotations = line.annotations.clone();
895 annotations.sort_by_key(|a| Reverse(a.start_col));
897 // First, figure out where each label will be positioned.
899 // In the case where you have the following annotations:
901 // vec.push(vec.pop().unwrap());
902 // -------- - previous borrow ends here [C]
904 // |this makes no sense [B]
905 // previous borrow of `vec` occurs here [A]
907 // `annotations_position` will hold [(2, A), (1, B), (0, C)].
909 // We try, when possible, to stick the rightmost annotation at the end
910 // of the highlight line:
912 // vec.push(vec.pop().unwrap());
913 // --- --- - previous borrow ends here
915 // But sometimes that's not possible because one of the other
916 // annotations overlaps it. For example, from the test
917 // `span_overlap_label`, we have the following annotations
918 // (written on distinct lines for clarity):
924 // In this case, we can't stick the rightmost-most label on
925 // the highlight line, or we would get:
932 // which is totally weird. Instead we want:
940 // which is...less weird, at least. In fact, in general, if
941 // the rightmost span overlaps with any other span, we should
942 // use the "hang below" version, so we can at least make it
943 // clear where the span *starts*. There's an exception for this
944 // logic, when the labels do not have a message:
959 let mut annotations_position = vec![];
960 let mut line_len = 0;
962 for (i, annotation) in annotations.iter().enumerate() {
963 for (j, next) in annotations.iter().enumerate() {
964 if overlaps(next, annotation, 0) // This label overlaps with another one and both
965 && annotation.has_label() // take space (they have text and are not
966 && j > i // multiline lines).
968 // We're currently on the first line, move the label one line down
970 // If we're overlapping with an un-labelled annotation with the same span
971 // we can just merge them in the output
972 if next.start_col == annotation.start_col
973 && next.end_col == annotation.end_col
979 // This annotation needs a new line in the output.
984 annotations_position.push((p, annotation));
985 for (j, next) in annotations.iter().enumerate() {
987 let l = next.label.as_ref().map_or(0, |label| label.len() + 2);
988 if (overlaps(next, annotation, l) // Do not allow two labels to be in the same
989 // line if they overlap including padding, to
990 // avoid situations like:
997 && annotation.has_label() // Both labels must have some text, otherwise
998 && next.has_label()) // they are not overlapping.
999 // Do not add a new line if this annotation
1000 // or the next are vertical line placeholders.
1001 || (annotation.takes_space() // If either this or the next annotation is
1002 && next.has_label()) // multiline start/end, move it to a new line
1003 || (annotation.has_label() // so as not to overlap the horizontal lines.
1004 && next.takes_space())
1005 || (annotation.takes_space() && next.takes_space())
1006 || (overlaps(next, annotation, l)
1007 && next.end_col <= annotation.end_col
1012 // This annotation needs a new line in the output.
1018 line_len = max(line_len, p);
1025 // If there are no annotations or the only annotations on this line are
1026 // MultilineLine, then there's only code being shown, stop processing.
1027 if line.annotations.iter().all(|a| a.is_line()) {
1031 // Write the column separator.
1033 // After this we will have:
1042 for pos in 0..=line_len {
1043 draw_col_separator(buffer, line_offset + pos + 1, width_offset - 2);
1046 // Write the horizontal lines for multiline annotations
1047 // (only the first and last lines need this).
1049 // After this we will have:
1058 for &(pos, annotation) in &annotations_position {
1059 let style = if annotation.is_primary {
1060 Style::UnderlinePrimary
1062 Style::UnderlineSecondary
1065 match annotation.annotation_type {
1066 AnnotationType::MultilineStart(depth) | AnnotationType::MultilineEnd(depth) => {
1071 width_offset + depth,
1072 (code_offset + annotation.start_col).saturating_sub(left),
1076 _ if self.teach => {
1077 buffer.set_style_range(
1079 (code_offset + annotation.start_col).saturating_sub(left),
1080 (code_offset + annotation.end_col).saturating_sub(left),
1082 annotation.is_primary,
1089 // Write the vertical lines for labels that are on a different line as the underline.
1091 // After this we will have:
1100 for &(pos, annotation) in &annotations_position {
1101 let style = if annotation.is_primary {
1102 Style::UnderlinePrimary
1104 Style::UnderlineSecondary
1108 if pos > 1 && (annotation.has_label() || annotation.takes_space()) {
1109 for p in line_offset + 1..=line_offset + pos {
1112 (code_offset + annotation.start_col).saturating_sub(left),
1118 match annotation.annotation_type {
1119 AnnotationType::MultilineStart(depth) => {
1120 for p in line_offset + pos + 1..line_offset + line_len + 2 {
1121 buffer.putc(p, width_offset + depth - 1, '|', style);
1124 AnnotationType::MultilineEnd(depth) => {
1125 for p in line_offset..=line_offset + pos {
1126 buffer.putc(p, width_offset + depth - 1, '|', style);
1133 // Write the labels on the annotations that actually have a label.
1135 // After this we will have:
1140 // | something about `foo`
1144 for &(pos, annotation) in &annotations_position {
1146 if annotation.is_primary { Style::LabelPrimary } else { Style::LabelSecondary };
1147 let (pos, col) = if pos == 0 {
1148 (pos + 1, (annotation.end_col + 1).saturating_sub(left))
1150 (pos + 2, annotation.start_col.saturating_sub(left))
1152 if let Some(ref label) = annotation.label {
1153 buffer.puts(line_offset + pos, code_offset + col, label, style);
1157 // Sort from biggest span to smallest span so that smaller spans are
1158 // represented in the output:
1163 // | | something about `foo`
1164 // | something about `fn foo()`
1165 annotations_position.sort_by_key(|(_, ann)| {
1166 // Decreasing order. When annotations share the same length, prefer `Primary`.
1167 (Reverse(ann.len()), ann.is_primary)
1170 // Write the underlines.
1172 // After this we will have:
1177 // | something about `foo`
1181 for &(_, annotation) in &annotations_position {
1182 let (underline, style) = if annotation.is_primary {
1183 ('^', Style::UnderlinePrimary)
1185 ('-', Style::UnderlineSecondary)
1187 for p in annotation.start_col..annotation.end_col {
1190 (code_offset + p).saturating_sub(left),
1196 annotations_position
1198 .filter_map(|&(_, annotation)| match annotation.annotation_type {
1199 AnnotationType::MultilineStart(p) | AnnotationType::MultilineEnd(p) => {
1200 let style = if annotation.is_primary {
1203 Style::LabelSecondary
1209 .collect::<Vec<_>>()
1212 fn get_multispan_max_line_num(&mut self, msp: &MultiSpan) -> usize {
1213 let Some(ref sm) = self.sm else {
1217 let will_be_emitted = |span: Span| {
1218 !span.is_dummy() && {
1219 let file = sm.lookup_source_file(span.hi());
1220 sm.ensure_source_file_source_present(file)
1225 for primary_span in msp.primary_spans() {
1226 if will_be_emitted(*primary_span) {
1227 let hi = sm.lookup_char_pos(primary_span.hi());
1228 max = (hi.line).max(max);
1231 if !self.short_message {
1232 for span_label in msp.span_labels() {
1233 if will_be_emitted(span_label.span) {
1234 let hi = sm.lookup_char_pos(span_label.span.hi());
1235 max = (hi.line).max(max);
1243 fn get_max_line_num(&mut self, span: &MultiSpan, children: &[SubDiagnostic]) -> usize {
1244 let primary = self.get_multispan_max_line_num(span);
1247 .map(|sub| self.get_multispan_max_line_num(&sub.span))
1253 /// Adds a left margin to every line but the first, given a padding length and the label being
1254 /// displayed, keeping the provided highlighting.
1257 buffer: &mut StyledBuffer,
1258 msg: &[(DiagnosticMessage, Style)],
1259 args: &FluentArgs<'_>,
1262 override_style: Option<Style>,
1264 // The extra 5 ` ` is padding that's always needed to align to the `note: `:
1267 // --> file.rs:13:20
1272 // = note: multiline
1277 // | | length of label
1279 // `max_line_num_len`
1280 let padding = " ".repeat(padding + label.len() + 5);
1282 /// Returns `override` if it is present and `style` is `NoStyle` or `style` otherwise
1283 fn style_or_override(style: Style, override_: Option<Style>) -> Style {
1284 match (style, override_) {
1285 (Style::NoStyle, Some(override_)) => override_,
1290 let mut line_number = 0;
1292 // Provided the following diagnostic message:
1296 // ("highlighted multiline\nstring to\nsee how it ", Style::NoStyle),
1297 // ("looks", Style::Highlight),
1298 // ("with\nvery ", Style::NoStyle),
1299 // ("weird", Style::Highlight),
1300 // (" formats\n", Style::NoStyle),
1301 // ("see?", Style::Highlight),
1304 // the expected output on a note is (* surround the highlighted text)
1306 // = note: highlighted multiline
1308 // see how it *looks* with
1309 // very *weird* formats
1311 for (text, style) in msg.iter() {
1312 let text = self.translate_message(text, args);
1313 let lines = text.split('\n').collect::<Vec<_>>();
1314 if lines.len() > 1 {
1315 for (i, line) in lines.iter().enumerate() {
1318 buffer.append(line_number, &padding, Style::NoStyle);
1320 buffer.append(line_number, line, style_or_override(*style, override_style));
1323 buffer.append(line_number, &text, style_or_override(*style, override_style));
1328 #[instrument(level = "trace", skip(self, args), ret)]
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 (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);
1390 trace!("{annotated_files:#?}");
1392 // Make sure our primary file comes first
1393 let primary_span = msp.primary_span().unwrap_or_default();
1394 let (Some(sm), false) = (self.sm.as_ref(), primary_span.is_dummy()) else {
1395 // If we don't have span information, emit and exit
1396 return emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message);
1398 let primary_lo = sm.lookup_char_pos(primary_span.lo());
1400 annotated_files.binary_search_by(|x| x.file.name.cmp(&primary_lo.file.name))
1402 annotated_files.swap(0, pos);
1405 // Print out the annotate source lines that correspond with the error
1406 for annotated_file in annotated_files {
1407 // we can't annotate anything if the source is unavailable.
1408 if !sm.ensure_source_file_source_present(annotated_file.file.clone()) {
1409 if !self.short_message {
1410 // We'll just print an unannotated message.
1411 for (annotation_id, line) in annotated_file.lines.iter().enumerate() {
1412 let mut annotations = line.annotations.clone();
1413 annotations.sort_by_key(|a| Reverse(a.start_col));
1414 let mut line_idx = buffer.num_lines();
1416 let labels: Vec<_> = annotations
1418 .filter_map(|a| Some((a.label.as_ref()?, a.is_primary)))
1419 .filter(|(l, _)| !l.is_empty())
1422 if annotation_id == 0 || !labels.is_empty() {
1427 sm.filename_for_diagnostics(&annotated_file.file.name),
1428 sm.doctest_offset_line(
1429 &annotated_file.file.name,
1432 annotations[0].start_col + 1,
1434 Style::LineAndColumn,
1436 if annotation_id == 0 {
1437 buffer.prepend(line_idx, "--> ", Style::LineNumber);
1439 buffer.prepend(line_idx, "::: ", Style::LineNumber);
1441 for _ in 0..max_line_num_len {
1442 buffer.prepend(line_idx, " ", Style::NoStyle);
1446 for (label, is_primary) in labels.into_iter() {
1447 let style = if is_primary {
1450 Style::LabelSecondary
1452 buffer.prepend(line_idx, " |", Style::LineNumber);
1453 for _ in 0..max_line_num_len {
1454 buffer.prepend(line_idx, " ", Style::NoStyle);
1457 buffer.append(line_idx, " = note: ", style);
1458 for _ in 0..max_line_num_len {
1459 buffer.prepend(line_idx, " ", Style::NoStyle);
1461 buffer.append(line_idx, label, style);
1469 // print out the span location and spacer before we print the annotated source
1470 // to do this, we need to know if this span will be primary
1471 let is_primary = primary_lo.file.name == annotated_file.file.name;
1473 let loc = primary_lo.clone();
1474 if !self.short_message {
1475 // remember where we are in the output buffer for easy reference
1476 let buffer_msg_line_offset = buffer.num_lines();
1478 buffer.prepend(buffer_msg_line_offset, "--> ", Style::LineNumber);
1480 buffer_msg_line_offset,
1483 sm.filename_for_diagnostics(&loc.file.name),
1484 sm.doctest_offset_line(&loc.file.name, loc.line),
1487 Style::LineAndColumn,
1489 for _ in 0..max_line_num_len {
1490 buffer.prepend(buffer_msg_line_offset, " ", Style::NoStyle);
1497 sm.filename_for_diagnostics(&loc.file.name),
1498 sm.doctest_offset_line(&loc.file.name, loc.line),
1501 Style::LineAndColumn,
1504 } else if !self.short_message {
1505 // remember where we are in the output buffer for easy reference
1506 let buffer_msg_line_offset = buffer.num_lines();
1509 draw_col_separator_no_space(
1511 buffer_msg_line_offset,
1512 max_line_num_len + 1,
1515 // Then, the secondary file indicator
1516 buffer.prepend(buffer_msg_line_offset + 1, "::: ", Style::LineNumber);
1517 let loc = if let Some(first_line) = annotated_file.lines.first() {
1518 let col = if let Some(first_annotation) = first_line.annotations.first() {
1519 format!(":{}", first_annotation.start_col + 1)
1525 sm.filename_for_diagnostics(&annotated_file.file.name),
1526 sm.doctest_offset_line(&annotated_file.file.name, first_line.line_index),
1530 format!("{}", sm.filename_for_diagnostics(&annotated_file.file.name))
1532 buffer.append(buffer_msg_line_offset + 1, &loc, Style::LineAndColumn);
1533 for _ in 0..max_line_num_len {
1534 buffer.prepend(buffer_msg_line_offset + 1, " ", Style::NoStyle);
1538 if !self.short_message {
1539 // Put in the spacer between the location and annotated source
1540 let buffer_msg_line_offset = buffer.num_lines();
1541 draw_col_separator_no_space(
1543 buffer_msg_line_offset,
1544 max_line_num_len + 1,
1547 // Contains the vertical lines' positions for active multiline annotations
1548 let mut multilines = FxIndexMap::default();
1550 // Get the left-side margin to remove it
1551 let mut whitespace_margin = usize::MAX;
1552 for line_idx in 0..annotated_file.lines.len() {
1553 let file = annotated_file.file.clone();
1554 let line = &annotated_file.lines[line_idx];
1555 if let Some(source_string) = file.get_line(line.line_index - 1) {
1556 let leading_whitespace = source_string
1558 .take_while(|c| c.is_whitespace())
1561 // Tabs are displayed as 4 spaces
1567 if source_string.chars().any(|c| !c.is_whitespace()) {
1568 whitespace_margin = min(whitespace_margin, leading_whitespace);
1572 if whitespace_margin == usize::MAX {
1573 whitespace_margin = 0;
1576 // Left-most column any visible span points at.
1577 let mut span_left_margin = usize::MAX;
1578 for line in &annotated_file.lines {
1579 for ann in &line.annotations {
1580 span_left_margin = min(span_left_margin, ann.start_col);
1581 span_left_margin = min(span_left_margin, ann.end_col);
1584 if span_left_margin == usize::MAX {
1585 span_left_margin = 0;
1588 // Right-most column any visible span points at.
1589 let mut span_right_margin = 0;
1590 let mut label_right_margin = 0;
1591 let mut max_line_len = 0;
1592 for line in &annotated_file.lines {
1595 annotated_file.file.get_line(line.line_index - 1).map_or(0, |s| s.len()),
1597 for ann in &line.annotations {
1598 span_right_margin = max(span_right_margin, ann.start_col);
1599 span_right_margin = max(span_right_margin, ann.end_col);
1600 // FIXME: account for labels not in the same line
1601 let label_right = ann.label.as_ref().map_or(0, |l| l.len() + 1);
1602 label_right_margin = max(label_right_margin, ann.end_col + label_right);
1606 let width_offset = 3 + max_line_num_len;
1607 let code_offset = if annotated_file.multiline_depth == 0 {
1610 width_offset + annotated_file.multiline_depth + 1
1613 let column_width = if let Some(width) = self.diagnostic_width {
1614 width.saturating_sub(code_offset)
1615 } else if self.ui_testing {
1616 DEFAULT_COLUMN_WIDTH
1618 termize::dimensions()
1619 .map(|(w, _)| w.saturating_sub(code_offset))
1620 .unwrap_or(DEFAULT_COLUMN_WIDTH)
1623 let margin = Margin::new(
1632 // Next, output the annotate source for this file
1633 for line_idx in 0..annotated_file.lines.len() {
1634 let previous_buffer_line = buffer.num_lines();
1636 let depths = self.render_source_line(
1638 annotated_file.file.clone(),
1639 &annotated_file.lines[line_idx],
1645 let mut to_add = FxHashMap::default();
1647 for (depth, style) in depths {
1648 if multilines.remove(&depth).is_none() {
1649 to_add.insert(depth, style);
1653 // Set the multiline annotation vertical lines to the left of
1654 // the code in this line.
1655 for (depth, style) in &multilines {
1656 for line in previous_buffer_line..buffer.num_lines() {
1657 draw_multiline_line(&mut buffer, line, width_offset, *depth, *style);
1660 // check to see if we need to print out or elide lines that come between
1661 // this annotated line and the next one.
1662 if line_idx < (annotated_file.lines.len() - 1) {
1663 let line_idx_delta = annotated_file.lines[line_idx + 1].line_index
1664 - annotated_file.lines[line_idx].line_index;
1665 if line_idx_delta > 2 {
1666 let last_buffer_line_num = buffer.num_lines();
1667 buffer.puts(last_buffer_line_num, 0, "...", Style::LineNumber);
1669 // Set the multiline annotation vertical lines on `...` bridging line.
1670 for (depth, style) in &multilines {
1671 draw_multiline_line(
1673 last_buffer_line_num,
1679 } else if line_idx_delta == 2 {
1680 let unannotated_line = annotated_file
1682 .get_line(annotated_file.lines[line_idx].line_index)
1683 .unwrap_or_else(|| Cow::from(""));
1685 let last_buffer_line_num = buffer.num_lines();
1689 &normalize_whitespace(&unannotated_line),
1690 annotated_file.lines[line_idx + 1].line_index - 1,
1691 last_buffer_line_num,
1697 for (depth, style) in &multilines {
1698 draw_multiline_line(
1700 last_buffer_line_num,
1709 multilines.extend(&to_add);
1712 trace!("buffer: {:#?}", buffer.render());
1715 if let Some(tracked) = emitted_at {
1716 let track = format!("-Ztrack-diagnostics: created at {tracked}");
1717 let len = buffer.num_lines();
1718 buffer.append(len, &track, Style::NoStyle);
1721 // final step: take our styled buffer, render it, then output it
1722 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1727 fn emit_suggestion_default(
1730 suggestion: &CodeSuggestion,
1731 args: &FluentArgs<'_>,
1733 max_line_num_len: usize,
1734 ) -> io::Result<()> {
1735 let Some(ref sm) = self.sm else {
1739 // Render the replacements for each suggestion
1740 let suggestions = suggestion.splice_lines(sm);
1741 debug!("emit_suggestion_default: suggestions={:?}", suggestions);
1743 if suggestions.is_empty() {
1744 // Suggestions coming from macros can have malformed spans. This is a heavy handed
1745 // approach to avoid ICEs by ignoring the suggestion outright.
1749 let mut buffer = StyledBuffer::new();
1751 // Render the suggestion message
1752 buffer.append(0, level.to_str(), Style::Level(*level));
1753 buffer.append(0, ": ", Style::HeaderMsg);
1757 &[(suggestion.msg.to_owned(), Style::NoStyle)],
1761 Some(Style::HeaderMsg),
1764 let mut row_num = 2;
1765 draw_col_separator_no_space(&mut buffer, 1, max_line_num_len + 1);
1766 let mut notice_capitalization = false;
1767 for (complete, parts, highlights, only_capitalization) in
1768 suggestions.iter().take(MAX_SUGGESTIONS)
1770 notice_capitalization |= only_capitalization;
1772 let has_deletion = parts.iter().any(|p| p.is_deletion(sm));
1773 let is_multiline = complete.lines().count() > 1;
1775 if let Some(span) = span.primary_span() {
1776 // Compare the primary span of the diagnostic with the span of the suggestion
1777 // being emitted. If they belong to the same file, we don't *need* to show the
1778 // file name, saving in verbosity, but if it *isn't* we do need it, otherwise we're
1779 // telling users to make a change but not clarifying *where*.
1780 let loc = sm.lookup_char_pos(parts[0].span.lo());
1781 if loc.file.name != sm.span_to_filename(span) && loc.file.name.is_real() {
1782 buffer.puts(row_num - 1, 0, "--> ", Style::LineNumber);
1787 sm.filename_for_diagnostics(&loc.file.name),
1788 sm.doctest_offset_line(&loc.file.name, loc.line),
1791 Style::LineAndColumn,
1793 for _ in 0..max_line_num_len {
1794 buffer.prepend(row_num - 1, " ", Style::NoStyle);
1799 let show_code_change = if has_deletion && !is_multiline {
1800 DisplaySuggestion::Diff
1801 } else if (parts.len() != 1 || parts[0].snippet.trim() != complete.trim())
1804 DisplaySuggestion::Underline
1806 DisplaySuggestion::None
1809 if let DisplaySuggestion::Diff = show_code_change {
1814 .span_to_lines(parts[0].span)
1815 .expect("span_to_lines failed when emitting suggestion");
1817 assert!(!file_lines.lines.is_empty() || parts[0].span.is_dummy());
1819 let line_start = sm.lookup_char_pos(parts[0].span.lo()).line;
1820 draw_col_separator_no_space(&mut buffer, row_num - 1, max_line_num_len + 1);
1821 let mut lines = complete.lines();
1822 if lines.clone().next().is_none() {
1823 // Account for a suggestion to completely remove a line(s) with whitespace (#94192).
1824 let line_end = sm.lookup_char_pos(parts[0].span.hi()).line;
1825 for line in line_start..=line_end {
1827 row_num - 1 + line - line_start,
1829 &self.maybe_anonymized(line),
1833 row_num - 1 + line - line_start,
1834 max_line_num_len + 1,
1839 row_num - 1 + line - line_start,
1840 max_line_num_len + 3,
1841 &normalize_whitespace(&file_lines.file.get_line(line - 1).unwrap()),
1845 row_num += line_end - line_start;
1847 let mut unhighlighted_lines = Vec::new();
1848 for (line_pos, (line, highlight_parts)) in lines.by_ref().zip(highlights).enumerate() {
1849 debug!(%line_pos, %line, ?highlight_parts);
1851 // Remember lines that are not highlighted to hide them if needed
1852 if highlight_parts.is_empty() {
1853 unhighlighted_lines.push((line_pos, line));
1857 match unhighlighted_lines.len() {
1859 // Since we show first line, "..." line and last line,
1860 // There is no reason to hide if there are 3 or less lines
1861 // (because then we just replace a line with ... which is
1863 n if n <= 3 => unhighlighted_lines.drain(..).for_each(|(p, l)| {
1864 self.draw_code_line(
1877 // Print first unhighlighted line, "..." and last unhighlighted line, like so:
1879 // LL | this line was highlighted
1880 // LL | this line is just for context
1882 // LL | this line is just for context
1883 // LL | this line was highlighted
1885 let last_line = unhighlighted_lines.pop();
1886 let first_line = unhighlighted_lines.drain(..).next();
1888 first_line.map(|(p, l)| {
1889 self.draw_code_line(
1903 buffer.puts(row_num, max_line_num_len - 1, "...", Style::LineNumber);
1906 last_line.map(|(p, l)| {
1907 self.draw_code_line(
1923 self.draw_code_line(
1937 // This offset and the ones below need to be signed to account for replacement code
1938 // that is shorter than the original code.
1939 let mut offsets: Vec<(usize, isize)> = Vec::new();
1940 // Only show an underline in the suggestions if the suggestion is not the
1941 // entirety of the code being shown and the displayed code is not multiline.
1942 if let DisplaySuggestion::Diff | DisplaySuggestion::Underline = show_code_change {
1943 draw_col_separator_no_space(&mut buffer, row_num, max_line_num_len + 1);
1945 let span_start_pos = sm.lookup_char_pos(part.span.lo()).col_display;
1946 let span_end_pos = sm.lookup_char_pos(part.span.hi()).col_display;
1948 // If this addition is _only_ whitespace, then don't trim it,
1949 // or else we're just not rendering anything.
1950 let is_whitespace_addition = part.snippet.trim().is_empty();
1952 // Do not underline the leading...
1953 let start = if is_whitespace_addition {
1956 part.snippet.len().saturating_sub(part.snippet.trim_start().len())
1958 // ...or trailing spaces. Account for substitutions containing unicode
1960 let sub_len: usize =
1961 if is_whitespace_addition { &part.snippet } else { part.snippet.trim() }
1963 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
1966 let offset: isize = offsets
1969 |(start, v)| if span_start_pos <= *start { None } else { Some(v) },
1972 let underline_start = (span_start_pos + start) as isize + offset;
1973 let underline_end = (span_start_pos + start + sub_len) as isize + offset;
1974 assert!(underline_start >= 0 && underline_end >= 0);
1975 let padding: usize = max_line_num_len + 3;
1976 for p in underline_start..underline_end {
1977 if let DisplaySuggestion::Underline = show_code_change {
1978 // If this is a replacement, underline with `^`, if this is an addition
1979 // underline with `+`.
1982 (padding as isize + p) as usize,
1983 if part.is_addition(sm) { '+' } else { '~' },
1988 if let DisplaySuggestion::Diff = show_code_change {
1989 // Colorize removal with red in diff format.
1990 buffer.set_style_range(
1992 (padding as isize + span_start_pos as isize) as usize,
1993 (padding as isize + span_end_pos as isize) as usize,
1999 // length of the code after substitution
2000 let full_sub_len = part
2003 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
2004 .sum::<usize>() as isize;
2006 // length of the code to be substituted
2007 let snippet_len = span_end_pos as isize - span_start_pos as isize;
2008 // For multiple substitutions, use the position *after* the previous
2009 // substitutions have happened, only when further substitutions are
2010 // located strictly after.
2011 offsets.push((span_end_pos, full_sub_len - snippet_len));
2016 // if we elided some lines, add an ellipsis
2017 if lines.next().is_some() {
2018 buffer.puts(row_num, max_line_num_len - 1, "...", Style::LineNumber);
2019 } else if let DisplaySuggestion::None = show_code_change {
2020 draw_col_separator_no_space(&mut buffer, row_num, max_line_num_len + 1);
2024 if suggestions.len() > MAX_SUGGESTIONS {
2025 let others = suggestions.len() - MAX_SUGGESTIONS;
2026 let msg = format!("and {} other candidate{}", others, pluralize!(others));
2027 buffer.puts(row_num, max_line_num_len + 3, &msg, Style::NoStyle);
2028 } else if notice_capitalization {
2029 let msg = "notice the capitalization difference";
2030 buffer.puts(row_num, max_line_num_len + 3, msg, Style::NoStyle);
2032 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
2036 #[instrument(level = "trace", skip(self, args, code, children, suggestions))]
2037 fn emit_messages_default(
2040 message: &[(DiagnosticMessage, Style)],
2041 args: &FluentArgs<'_>,
2042 code: &Option<DiagnosticId>,
2044 children: &[SubDiagnostic],
2045 suggestions: &[CodeSuggestion],
2046 emitted_at: Option<&DiagnosticLocation>,
2048 let max_line_num_len = if self.ui_testing {
2049 ANONYMIZED_LINE_NUM.len()
2051 let n = self.get_max_line_num(span, children);
2052 num_decimal_digits(n)
2055 match self.emit_message_default(
2066 if !children.is_empty()
2067 || suggestions.iter().any(|s| s.style != SuggestionStyle::CompletelyHidden)
2069 let mut buffer = StyledBuffer::new();
2070 if !self.short_message {
2071 draw_col_separator_no_space(&mut buffer, 0, max_line_num_len + 1);
2073 if let Err(e) = emit_to_destination(
2079 panic!("failed to emit error: {}", e)
2082 if !self.short_message {
2083 for child in children {
2084 let span = child.render_span.as_ref().unwrap_or(&child.span);
2085 if let Err(err) = self.emit_message_default(
2095 panic!("failed to emit error: {}", err);
2098 for sugg in suggestions {
2099 if sugg.style == SuggestionStyle::CompletelyHidden {
2100 // do not display this suggestion, it is meant only for tools
2101 } else if sugg.style == SuggestionStyle::HideCodeAlways {
2102 if let Err(e) = self.emit_message_default(
2104 &[(sugg.msg.to_owned(), Style::HeaderMsg)],
2112 panic!("failed to emit error: {}", e);
2114 } else if let Err(e) = self.emit_suggestion_default(
2121 panic!("failed to emit error: {}", e);
2126 Err(e) => panic!("failed to emit error: {}", e),
2129 let mut dst = self.dst.writable();
2130 match writeln!(dst) {
2131 Err(e) => panic!("failed to emit error: {}", e),
2133 if let Err(e) = dst.flush() {
2134 panic!("failed to emit error: {}", e)
2142 buffer: &mut StyledBuffer,
2143 row_num: &mut usize,
2144 highlight_parts: &Vec<SubstitutionHighlight>,
2148 show_code_change: DisplaySuggestion,
2149 max_line_num_len: usize,
2150 file_lines: &FileLines,
2153 // Print the span column to avoid confusion
2154 buffer.puts(*row_num, 0, &self.maybe_anonymized(line_start + line_pos), Style::LineNumber);
2155 if let DisplaySuggestion::Diff = show_code_change {
2156 // Add the line number for both addition and removal to drive the point home.
2158 // N - fn foo<A: T>(bar: A) {
2159 // N + fn foo(bar: impl T) {
2163 &self.maybe_anonymized(line_start + line_pos),
2166 buffer.puts(*row_num - 1, max_line_num_len + 1, "- ", Style::Removal);
2169 max_line_num_len + 3,
2170 &normalize_whitespace(
2171 &file_lines.file.get_line(file_lines.lines[line_pos].line_index).unwrap(),
2175 buffer.puts(*row_num, max_line_num_len + 1, "+ ", Style::Addition);
2176 } else if is_multiline {
2177 match &highlight_parts[..] {
2178 [SubstitutionHighlight { start: 0, end }] if *end == line.len() => {
2179 buffer.puts(*row_num, max_line_num_len + 1, "+ ", Style::Addition);
2182 draw_col_separator(buffer, *row_num, max_line_num_len + 1);
2185 buffer.puts(*row_num, max_line_num_len + 1, "~ ", Style::Addition);
2189 draw_col_separator(buffer, *row_num, max_line_num_len + 1);
2192 // print the suggestion
2193 buffer.append(*row_num, &normalize_whitespace(line), Style::NoStyle);
2195 // Colorize addition/replacements with green.
2196 for &SubstitutionHighlight { start, end } in highlight_parts {
2197 // Account for tabs when highlighting (#87972).
2198 let tabs: usize = line
2201 .map(|ch| match ch {
2206 buffer.set_style_range(
2208 max_line_num_len + 3 + start + tabs,
2209 max_line_num_len + 3 + end + tabs,
2218 #[derive(Clone, Copy, Debug)]
2219 enum DisplaySuggestion {
2225 impl FileWithAnnotatedLines {
2226 /// Preprocess all the annotations so that they are grouped by file and by line number
2227 /// This helps us quickly iterate over the whole message (including secondary file spans)
2228 pub fn collect_annotations(
2229 emitter: &dyn Emitter,
2230 args: &FluentArgs<'_>,
2232 ) -> Vec<FileWithAnnotatedLines> {
2233 fn add_annotation_to_file(
2234 file_vec: &mut Vec<FileWithAnnotatedLines>,
2235 file: Lrc<SourceFile>,
2239 for slot in file_vec.iter_mut() {
2240 // Look through each of our files for the one we're adding to
2241 if slot.file.name == file.name {
2242 // See if we already have a line for it
2243 for line_slot in &mut slot.lines {
2244 if line_slot.line_index == line_index {
2245 line_slot.annotations.push(ann);
2249 // We don't have a line yet, create one
2250 slot.lines.push(Line { line_index, annotations: vec![ann] });
2255 // This is the first time we're seeing the file
2256 file_vec.push(FileWithAnnotatedLines {
2258 lines: vec![Line { line_index, annotations: vec![ann] }],
2263 let mut output = vec![];
2264 let mut multiline_annotations = vec![];
2266 if let Some(ref sm) = emitter.source_map() {
2267 for SpanLabel { span, is_primary, label } in msp.span_labels() {
2268 // If we don't have a useful span, pick the primary span if that exists.
2269 // Worst case we'll just print an error at the top of the main file.
2270 let span = match (span.is_dummy(), msp.primary_span()) {
2271 (_, None) | (false, _) => span,
2272 (true, Some(span)) => span,
2275 let lo = sm.lookup_char_pos(span.lo());
2276 let mut hi = sm.lookup_char_pos(span.hi());
2278 // Watch out for "empty spans". If we get a span like 6..6, we
2279 // want to just display a `^` at 6, so convert that to
2280 // 6..7. This is degenerate input, but it's best to degrade
2281 // gracefully -- and the parser likes to supply a span like
2282 // that for EOF, in particular.
2284 if lo.col_display == hi.col_display && lo.line == hi.line {
2285 hi.col_display += 1;
2288 let label = label.as_ref().map(|m| emitter.translate_message(m, args).to_string());
2290 if lo.line != hi.line {
2291 let ml = MultilineAnnotation {
2293 line_start: lo.line,
2295 start_col: lo.col_display,
2296 end_col: hi.col_display,
2299 overlaps_exactly: false,
2301 multiline_annotations.push((lo.file, ml));
2303 let ann = Annotation {
2304 start_col: lo.col_display,
2305 end_col: hi.col_display,
2308 annotation_type: AnnotationType::Singleline,
2310 add_annotation_to_file(&mut output, lo.file, lo.line, ann);
2315 // Find overlapping multiline annotations, put them at different depths
2316 multiline_annotations.sort_by_key(|&(_, ref ml)| (ml.line_start, usize::MAX - ml.line_end));
2317 for (_, ann) in multiline_annotations.clone() {
2318 for (_, a) in multiline_annotations.iter_mut() {
2319 // Move all other multiline annotations overlapping with this one
2320 // one level to the right.
2321 if !(ann.same_span(a))
2322 && num_overlap(ann.line_start, ann.line_end, a.line_start, a.line_end, true)
2325 } else if ann.same_span(a) && &ann != a {
2326 a.overlaps_exactly = true;
2333 let mut max_depth = 0; // max overlapping multiline spans
2334 for (_, ann) in &multiline_annotations {
2335 max_depth = max(max_depth, ann.depth);
2337 // Change order of multispan depth to minimize the number of overlaps in the ASCII art.
2338 for (_, a) in multiline_annotations.iter_mut() {
2339 a.depth = max_depth - a.depth + 1;
2341 for (file, ann) in multiline_annotations {
2342 let mut end_ann = ann.as_end();
2343 if !ann.overlaps_exactly {
2344 // avoid output like
2366 add_annotation_to_file(&mut output, file.clone(), ann.line_start, ann.as_start());
2367 // 4 is the minimum vertical length of a multiline span when presented: two lines
2368 // of code and two lines of underline. This is not true for the special case where
2369 // the beginning doesn't have an underline, but the current logic seems to be
2370 // working correctly.
2371 let middle = min(ann.line_start + 4, ann.line_end);
2372 for line in ann.line_start + 1..middle {
2373 // Every `|` that joins the beginning of the span (`___^`) to the end (`|__^`).
2374 add_annotation_to_file(&mut output, file.clone(), line, ann.as_line());
2376 let line_end = ann.line_end - 1;
2377 if middle < line_end {
2378 add_annotation_to_file(&mut output, file.clone(), line_end, ann.as_line());
2381 end_ann.annotation_type = AnnotationType::Singleline;
2383 add_annotation_to_file(&mut output, file, ann.line_end, end_ann);
2385 for file_vec in output.iter_mut() {
2386 file_vec.multiline_depth = max_depth;
2392 // instead of taking the String length or dividing by 10 while > 0, we multiply a limit by 10 until
2393 // we're higher. If the loop isn't exited by the `return`, the last multiplication will wrap, which
2394 // is OK, because while we cannot fit a higher power of 10 in a usize, the loop will end anyway.
2395 // This is also why we need the max number of decimal digits within a `usize`.
2396 fn num_decimal_digits(num: usize) -> usize {
2397 #[cfg(target_pointer_width = "64")]
2398 const MAX_DIGITS: usize = 20;
2400 #[cfg(target_pointer_width = "32")]
2401 const MAX_DIGITS: usize = 10;
2403 #[cfg(target_pointer_width = "16")]
2404 const MAX_DIGITS: usize = 5;
2407 for num_digits in 1..MAX_DIGITS {
2411 lim = lim.wrapping_mul(10);
2416 // We replace some characters so the CLI output is always consistent and underlines aligned.
2417 const OUTPUT_REPLACEMENTS: &[(char, &str)] = &[
2418 ('\t', " "), // We do our own tab replacement
2419 ('\u{200D}', ""), // Replace ZWJ with nothing for consistent terminal output of grapheme clusters.
2420 ('\u{202A}', ""), // The following unicode text flow control characters are inconsistently
2421 ('\u{202B}', ""), // supported across CLIs and can cause confusion due to the bytes on disk
2422 ('\u{202D}', ""), // not corresponding to the visible source code, so we replace them always.
2431 fn normalize_whitespace(str: &str) -> String {
2432 let mut s = str.to_string();
2433 for (c, replacement) in OUTPUT_REPLACEMENTS {
2434 s = s.replace(*c, replacement);
2439 fn draw_col_separator(buffer: &mut StyledBuffer, line: usize, col: usize) {
2440 buffer.puts(line, col, "| ", Style::LineNumber);
2443 fn draw_col_separator_no_space(buffer: &mut StyledBuffer, line: usize, col: usize) {
2444 draw_col_separator_no_space_with_style(buffer, line, col, Style::LineNumber);
2447 fn draw_col_separator_no_space_with_style(
2448 buffer: &mut StyledBuffer,
2453 buffer.putc(line, col, '|', style);
2457 buffer: &mut StyledBuffer,
2464 for col in col_from..col_to {
2465 buffer.putc(line, col, symbol, style);
2469 fn draw_note_separator(buffer: &mut StyledBuffer, line: usize, col: usize) {
2470 buffer.puts(line, col, "= ", Style::LineNumber);
2473 fn draw_multiline_line(
2474 buffer: &mut StyledBuffer,
2480 buffer.putc(line, offset + depth - 1, '|', style);
2490 let extra = if inclusive { 1 } else { 0 };
2491 (b_start..b_end + extra).contains(&a_start) || (a_start..a_end + extra).contains(&b_start)
2493 fn overlaps(a1: &Annotation, a2: &Annotation, padding: usize) -> bool {
2494 num_overlap(a1.start_col, a1.end_col + padding, a2.start_col, a2.end_col, false)
2497 fn emit_to_destination(
2498 rendered_buffer: &[Vec<StyledString>],
2500 dst: &mut Destination,
2501 short_message: bool,
2502 ) -> io::Result<()> {
2505 let mut dst = dst.writable();
2507 // In order to prevent error message interleaving, where multiple error lines get intermixed
2508 // when multiple compiler processes error simultaneously, we emit errors with additional
2511 // On Unix systems, we write into a buffered terminal rather than directly to a terminal. When
2512 // the .flush() is called we take the buffer created from the buffered writes and write it at
2513 // one shot. Because the Unix systems use ANSI for the colors, which is a text-based styling
2514 // scheme, this buffered approach works and maintains the styling.
2516 // On Windows, styling happens through calls to a terminal API. This prevents us from using the
2517 // same buffering approach. Instead, we use a global Windows mutex, which we acquire long
2518 // enough to output the full error message, then we release.
2519 let _buffer_lock = lock::acquire_global_lock("rustc_errors");
2520 for (pos, line) in rendered_buffer.iter().enumerate() {
2522 dst.apply_style(*lvl, part.style)?;
2523 write!(dst, "{}", part.text)?;
2526 if !short_message && (!lvl.is_failure_note() || pos != rendered_buffer.len() - 1) {
2534 pub enum Destination {
2535 Terminal(StandardStream),
2536 Buffered(BufferWriter),
2537 // The bool denotes whether we should be emitting ansi color codes or not
2538 Raw(Box<(dyn Write + Send)>, bool),
2541 pub enum WritableDst<'a> {
2542 Terminal(&'a mut StandardStream),
2543 Buffered(&'a mut BufferWriter, Buffer),
2544 Raw(&'a mut (dyn Write + Send)),
2545 ColoredRaw(Ansi<&'a mut (dyn Write + Send)>),
2549 fn from_stderr(color: ColorConfig) -> Destination {
2550 let choice = color.to_color_choice();
2551 // On Windows we'll be performing global synchronization on the entire
2552 // system for emitting rustc errors, so there's no need to buffer
2555 // On non-Windows we rely on the atomicity of `write` to ensure errors
2556 // don't get all jumbled up.
2558 Terminal(StandardStream::stderr(choice))
2560 Buffered(BufferWriter::stderr(choice))
2564 fn writable(&mut self) -> WritableDst<'_> {
2566 Destination::Terminal(ref mut t) => WritableDst::Terminal(t),
2567 Destination::Buffered(ref mut t) => {
2568 let buf = t.buffer();
2569 WritableDst::Buffered(t, buf)
2571 Destination::Raw(ref mut t, false) => WritableDst::Raw(t),
2572 Destination::Raw(ref mut t, true) => WritableDst::ColoredRaw(Ansi::new(t)),
2576 fn supports_color(&self) -> bool {
2578 Self::Terminal(ref stream) => stream.supports_color(),
2579 Self::Buffered(ref buffer) => buffer.buffer().supports_color(),
2580 Self::Raw(_, supports_color) => supports_color,
2585 impl<'a> WritableDst<'a> {
2586 fn apply_style(&mut self, lvl: Level, style: Style) -> io::Result<()> {
2587 let mut spec = ColorSpec::new();
2589 Style::Addition => {
2590 spec.set_fg(Some(Color::Green)).set_intense(true);
2593 spec.set_fg(Some(Color::Red)).set_intense(true);
2595 Style::LineAndColumn => {}
2596 Style::LineNumber => {
2597 spec.set_bold(true);
2598 spec.set_intense(true);
2600 spec.set_fg(Some(Color::Cyan));
2602 spec.set_fg(Some(Color::Blue));
2605 Style::Quotation => {}
2606 Style::MainHeaderMsg => {
2607 spec.set_bold(true);
2609 spec.set_intense(true).set_fg(Some(Color::White));
2612 Style::UnderlinePrimary | Style::LabelPrimary => {
2614 spec.set_bold(true);
2616 Style::UnderlineSecondary | Style::LabelSecondary => {
2617 spec.set_bold(true).set_intense(true);
2619 spec.set_fg(Some(Color::Cyan));
2621 spec.set_fg(Some(Color::Blue));
2624 Style::HeaderMsg | Style::NoStyle => {}
2625 Style::Level(lvl) => {
2627 spec.set_bold(true);
2629 Style::Highlight => {
2630 spec.set_bold(true);
2633 self.set_color(&spec)
2636 fn set_color(&mut self, color: &ColorSpec) -> io::Result<()> {
2638 WritableDst::Terminal(ref mut t) => t.set_color(color),
2639 WritableDst::Buffered(_, ref mut t) => t.set_color(color),
2640 WritableDst::ColoredRaw(ref mut t) => t.set_color(color),
2641 WritableDst::Raw(_) => Ok(()),
2645 fn reset(&mut self) -> io::Result<()> {
2647 WritableDst::Terminal(ref mut t) => t.reset(),
2648 WritableDst::Buffered(_, ref mut t) => t.reset(),
2649 WritableDst::ColoredRaw(ref mut t) => t.reset(),
2650 WritableDst::Raw(_) => Ok(()),
2655 impl<'a> Write for WritableDst<'a> {
2656 fn write(&mut self, bytes: &[u8]) -> io::Result<usize> {
2658 WritableDst::Terminal(ref mut t) => t.write(bytes),
2659 WritableDst::Buffered(_, ref mut buf) => buf.write(bytes),
2660 WritableDst::Raw(ref mut w) => w.write(bytes),
2661 WritableDst::ColoredRaw(ref mut t) => t.write(bytes),
2665 fn flush(&mut self) -> io::Result<()> {
2667 WritableDst::Terminal(ref mut t) => t.flush(),
2668 WritableDst::Buffered(_, ref mut buf) => buf.flush(),
2669 WritableDst::Raw(ref mut w) => w.flush(),
2670 WritableDst::ColoredRaw(ref mut w) => w.flush(),
2675 impl<'a> Drop for WritableDst<'a> {
2676 fn drop(&mut self) {
2677 if let WritableDst::Buffered(ref mut dst, ref mut buf) = self {
2678 drop(dst.print(buf));
2683 /// Whether the original and suggested code are visually similar enough to warrant extra wording.
2684 pub fn is_case_difference(sm: &SourceMap, suggested: &str, sp: Span) -> bool {
2685 // FIXME: this should probably be extended to also account for `FO0` → `FOO` and unicode.
2686 let found = match sm.span_to_snippet(sp) {
2687 Ok(snippet) => snippet,
2689 warn!(error = ?e, "Invalid span {:?}", sp);
2693 let ascii_confusables = &['c', 'f', 'i', 'k', 'o', 's', 'u', 'v', 'w', 'x', 'y', 'z'];
2694 // All the chars that differ in capitalization are confusable (above):
2695 let confusable = iter::zip(found.chars(), suggested.chars())
2696 .filter(|(f, s)| f != s)
2697 .all(|(f, s)| (ascii_confusables.contains(&f) || ascii_confusables.contains(&s)));
2698 confusable && found.to_lowercase() == suggested.to_lowercase()
2699 // FIXME: We sometimes suggest the same thing we already have, which is a
2700 // bug, but be defensive against that here.
2701 && found != suggested