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 CodeSuggestion, Diagnostic, DiagnosticId, DiagnosticMessage, FluentBundle, Handler,
20 LazyFallbackBundle, Level, MultiSpan, SubDiagnostic, 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,
68 let (short, color_config) = self.unzip();
69 let color = color_config.suggests_using_colors();
84 #[derive(Clone, Copy, Debug)]
86 /// The available whitespace in the left that can be consumed when centering.
87 pub whitespace_left: usize,
88 /// The column of the beginning of left-most span.
90 /// The column of the end of right-most span.
91 pub span_right: usize,
92 /// The beginning of the line to be displayed.
93 pub computed_left: usize,
94 /// The end of the line to be displayed.
95 pub computed_right: usize,
96 /// The current width of the terminal. Uses value of `DEFAULT_COLUMN_WIDTH` constant by default
98 pub column_width: usize,
99 /// The end column of a span label, including the span. Doesn't account for labels not in the
100 /// same line as the span.
101 pub label_right: usize,
106 whitespace_left: usize,
113 // The 6 is padding to give a bit of room for `...` when displaying:
118 // 16 | ... fn foo(self) -> Self::Bar {
123 whitespace_left: whitespace_left.saturating_sub(6),
124 span_left: span_left.saturating_sub(6),
125 span_right: span_right + 6,
129 label_right: label_right + 6,
131 m.compute(max_line_len);
135 fn was_cut_left(&self) -> bool {
136 self.computed_left > 0
139 fn was_cut_right(&self, line_len: usize) -> bool {
141 if self.computed_right == self.span_right || self.computed_right == self.label_right {
142 // Account for the "..." padding given above. Otherwise we end up with code lines that
143 // do fit but end in "..." as if they were trimmed.
144 self.computed_right - 6
148 right < line_len && self.computed_left + self.column_width < line_len
151 fn compute(&mut self, max_line_len: usize) {
152 // When there's a lot of whitespace (>20), we want to trim it as it is useless.
153 self.computed_left = if self.whitespace_left > 20 {
154 self.whitespace_left - 16 // We want some padding.
158 // We want to show as much as possible, max_line_len is the right-most boundary for the
160 self.computed_right = max(max_line_len, self.computed_left);
162 if self.computed_right - self.computed_left > self.column_width {
163 // Trimming only whitespace isn't enough, let's get craftier.
164 if self.label_right - self.whitespace_left <= self.column_width {
165 // Attempt to fit the code window only trimming whitespace.
166 self.computed_left = self.whitespace_left;
167 self.computed_right = self.computed_left + self.column_width;
168 } else if self.label_right - self.span_left <= self.column_width {
169 // Attempt to fit the code window considering only the spans and labels.
170 let padding_left = (self.column_width - (self.label_right - self.span_left)) / 2;
171 self.computed_left = self.span_left.saturating_sub(padding_left);
172 self.computed_right = self.computed_left + self.column_width;
173 } else if self.span_right - self.span_left <= self.column_width {
174 // Attempt to fit the code window considering the spans and labels plus padding.
175 let padding_left = (self.column_width - (self.span_right - self.span_left)) / 5 * 2;
176 self.computed_left = self.span_left.saturating_sub(padding_left);
177 self.computed_right = self.computed_left + self.column_width;
179 // Mostly give up but still don't show the full line.
180 self.computed_left = self.span_left;
181 self.computed_right = self.span_right;
186 fn left(&self, line_len: usize) -> usize {
187 min(self.computed_left, line_len)
190 fn right(&self, line_len: usize) -> usize {
191 if line_len.saturating_sub(self.computed_left) <= self.column_width {
194 min(line_len, self.computed_right)
199 const ANONYMIZED_LINE_NUM: &str = "LL";
201 /// Emitter trait for emitting errors.
202 pub trait Emitter: Translate {
203 /// Emit a structured diagnostic.
204 fn emit_diagnostic(&mut self, diag: &Diagnostic);
206 /// Emit a notification that an artifact has been output.
207 /// This is currently only supported for the JSON format,
208 /// other formats can, and will, simply ignore it.
209 fn emit_artifact_notification(&mut self, _path: &Path, _artifact_type: &str) {}
211 fn emit_future_breakage_report(&mut self, _diags: Vec<Diagnostic>) {}
213 /// Emit list of unused externs
214 fn emit_unused_externs(
216 _lint_level: rustc_lint_defs::Level,
217 _unused_externs: &[&str],
221 /// Checks if should show explanations about "rustc --explain"
222 fn should_show_explain(&self) -> bool {
226 /// Checks if we can use colors in the current output stream.
227 fn supports_color(&self) -> bool {
231 fn source_map(&self) -> Option<&Lrc<SourceMap>>;
233 /// Formats the substitutions of the primary_span
235 /// There are a lot of conditions to this method, but in short:
237 /// * If the current `Diagnostic` has only one visible `CodeSuggestion`,
238 /// we format the `help` suggestion depending on the content of the
239 /// substitutions. In that case, we return the modified span only.
241 /// * If the current `Diagnostic` has multiple suggestions,
242 /// we return the original `primary_span` and the original suggestions.
243 fn primary_span_formatted<'a>(
245 diag: &'a Diagnostic,
246 fluent_args: &FluentArgs<'_>,
247 ) -> (MultiSpan, &'a [CodeSuggestion]) {
248 let mut primary_span = diag.span.clone();
249 let suggestions = diag.suggestions.as_ref().map_or(&[][..], |suggestions| &suggestions[..]);
250 if let Some((sugg, rest)) = suggestions.split_first() {
251 let msg = self.translate_message(&sugg.msg, fluent_args);
252 if rest.is_empty() &&
253 // ^ if there is only one suggestion
254 // don't display multi-suggestions as labels
255 sugg.substitutions.len() == 1 &&
256 // don't display multipart suggestions as labels
257 sugg.substitutions[0].parts.len() == 1 &&
258 // don't display long messages as labels
259 msg.split_whitespace().count() < 10 &&
260 // don't display multiline suggestions as labels
261 !sugg.substitutions[0].parts[0].snippet.contains('\n') &&
263 // when this style is set we want the suggestion to be a message, not inline
264 SuggestionStyle::HideCodeAlways,
265 // trivial suggestion for tooling's sake, never shown
266 SuggestionStyle::CompletelyHidden,
267 // subtle suggestion, never shown inline
268 SuggestionStyle::ShowAlways,
269 ].contains(&sugg.style)
271 let substitution = &sugg.substitutions[0].parts[0].snippet.trim();
272 let msg = if substitution.is_empty() || sugg.style.hide_inline() {
273 // This substitution is only removal OR we explicitly don't want to show the
274 // code inline (`hide_inline`). Therefore, we don't show the substitution.
275 format!("help: {}", &msg)
277 // Show the default suggestion text with the substitution
283 .map(|sm| is_case_difference(
286 sugg.substitutions[0].parts[0].span,
290 " (notice the capitalization)"
297 primary_span.push_span_label(sugg.substitutions[0].parts[0].span, msg);
299 // We return only the modified primary_span
302 // if there are multiple suggestions, print them all in full
303 // to be consistent. We could try to figure out if we can
304 // make one (or the first one) inline, but that would give
305 // undue importance to a semi-random suggestion
306 (primary_span, suggestions)
309 (primary_span, suggestions)
313 fn fix_multispans_in_extern_macros_and_render_macro_backtrace(
315 source_map: &Option<Lrc<SourceMap>>,
316 span: &mut MultiSpan,
317 children: &mut Vec<SubDiagnostic>,
321 // Check for spans in macros, before `fix_multispans_in_extern_macros`
322 // has a chance to replace them.
323 let has_macro_spans: Vec<_> = iter::once(&*span)
324 .chain(children.iter().map(|child| &child.span))
325 .flat_map(|span| span.primary_spans())
326 .flat_map(|sp| sp.macro_backtrace())
327 .filter_map(|expn_data| {
328 match expn_data.kind {
329 ExpnKind::Root => None,
331 // Skip past non-macro entries, just in case there
332 // are some which do actually involve macros.
333 ExpnKind::Inlined | ExpnKind::Desugaring(..) | ExpnKind::AstPass(..) => None,
335 ExpnKind::Macro(macro_kind, name) => Some((macro_kind, name)),
341 self.fix_multispans_in_extern_macros(source_map, span, children);
344 self.render_multispans_macro_backtrace(span, children, backtrace);
347 if let Some((macro_kind, name)) = has_macro_spans.first() {
348 // Mark the actual macro this originates from
349 let and_then = if let Some((macro_kind, last_name)) = has_macro_spans.last()
352 let descr = macro_kind.descr();
354 " which comes from the expansion of the {descr} `{last_name}`",
360 let descr = macro_kind.descr();
362 "this {level} originates in the {descr} `{name}`{and_then} \
363 (in Nightly builds, run with -Z macro-backtrace for more info)",
366 children.push(SubDiagnostic {
368 message: vec![(DiagnosticMessage::Str(msg), Style::NoStyle)],
369 span: MultiSpan::new(),
376 fn render_multispans_macro_backtrace(
378 span: &mut MultiSpan,
379 children: &mut Vec<SubDiagnostic>,
382 for span in iter::once(span).chain(children.iter_mut().map(|child| &mut child.span)) {
383 self.render_multispan_macro_backtrace(span, backtrace);
387 fn render_multispan_macro_backtrace(&self, span: &mut MultiSpan, always_backtrace: bool) {
388 let mut new_labels: Vec<(Span, String)> = vec![];
390 for &sp in span.primary_spans() {
395 // FIXME(eddyb) use `retain` on `macro_backtrace` to remove all the
396 // entries we don't want to print, to make sure the indices being
397 // printed are contiguous (or omitted if there's only one entry).
398 let macro_backtrace: Vec<_> = sp.macro_backtrace().collect();
399 for (i, trace) in macro_backtrace.iter().rev().enumerate() {
400 if trace.def_site.is_dummy() {
404 if always_backtrace && !matches!(trace.kind, ExpnKind::Inlined) {
408 "in this expansion of `{}`{}",
410 if macro_backtrace.len() > 1 {
411 // if macro_backtrace.len() == 1 it'll be
412 // pointed at by "in this macro invocation"
413 format!(" (#{})", i + 1)
421 // Don't add a label on the call site if the diagnostic itself
422 // already points to (a part of) that call site, as the label
423 // is meant for showing the relevant invocation when the actual
424 // diagnostic is pointing to some part of macro definition.
426 // This also handles the case where an external span got replaced
427 // with the call site span by `fix_multispans_in_extern_macros`.
429 // NB: `-Zmacro-backtrace` overrides this, for uniformity, as the
430 // "in this expansion of" label above is always added in that mode,
431 // and it needs an "in this macro invocation" label to match that.
432 let redundant_span = trace.call_site.contains(sp);
434 if !redundant_span || always_backtrace {
435 let msg: Cow<'static, _> = match trace.kind {
436 ExpnKind::Macro(MacroKind::Attr, _) => {
437 "this procedural macro expansion".into()
439 ExpnKind::Macro(MacroKind::Derive, _) => {
440 "this derive macro expansion".into()
442 ExpnKind::Macro(MacroKind::Bang, _) => "this macro invocation".into(),
443 ExpnKind::Inlined => "this inlined function call".into(),
444 ExpnKind::Root => "the crate root".into(),
445 ExpnKind::AstPass(kind) => kind.descr().into(),
446 ExpnKind::Desugaring(kind) => {
447 format!("this {} desugaring", kind.descr()).into()
455 if macro_backtrace.len() > 1 && always_backtrace {
456 // only specify order when the macro
457 // backtrace is multiple levels deep
458 format!(" (#{})", i + 1)
465 if !always_backtrace {
471 for (label_span, label_text) in new_labels {
472 span.push_span_label(label_span, label_text);
476 // This does a small "fix" for multispans by looking to see if it can find any that
477 // point directly at external macros. Since these are often difficult to read,
478 // this will change the span to point at the use site.
479 fn fix_multispans_in_extern_macros(
481 source_map: &Option<Lrc<SourceMap>>,
482 span: &mut MultiSpan,
483 children: &mut Vec<SubDiagnostic>,
485 let Some(source_map) = source_map else { return };
486 debug!("fix_multispans_in_extern_macros: before: span={:?} children={:?}", span, children);
487 self.fix_multispan_in_extern_macros(source_map, span);
488 for child in children.iter_mut() {
489 self.fix_multispan_in_extern_macros(source_map, &mut child.span);
491 debug!("fix_multispans_in_extern_macros: after: span={:?} children={:?}", span, children);
494 // This "fixes" MultiSpans that contain `Span`s pointing to locations inside of external macros.
495 // Since these locations are often difficult to read,
496 // we move these spans from the external macros to their corresponding use site.
497 fn fix_multispan_in_extern_macros(&self, source_map: &Lrc<SourceMap>, span: &mut MultiSpan) {
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(
549 self.macro_backtrace,
552 self.emit_messages_default(
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 atty::is(atty::Stream::Stderr) {
625 ColorChoice::AlwaysAnsi
628 ColorConfig::Never => ColorChoice::Never,
629 ColorConfig::Auto if atty::is(atty::Stream::Stderr) => 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,
656 pub struct FileWithAnnotatedLines {
657 pub file: Lrc<SourceFile>,
658 pub lines: Vec<Line>,
659 multiline_depth: usize,
664 color_config: ColorConfig,
665 source_map: Option<Lrc<SourceMap>>,
666 fluent_bundle: Option<Lrc<FluentBundle>>,
667 fallback_bundle: LazyFallbackBundle,
670 diagnostic_width: Option<usize>,
671 macro_backtrace: bool,
673 let dst = Destination::from_stderr(color_config);
688 dst: Box<dyn Write + Send>,
689 source_map: Option<Lrc<SourceMap>>,
690 fluent_bundle: Option<Lrc<FluentBundle>>,
691 fallback_bundle: LazyFallbackBundle,
695 diagnostic_width: Option<usize>,
696 macro_backtrace: bool,
699 dst: Raw(dst, colored),
711 pub fn ui_testing(mut self, ui_testing: bool) -> Self {
712 self.ui_testing = ui_testing;
716 fn maybe_anonymized(&self, line_num: usize) -> Cow<'static, str> {
718 Cow::Borrowed(ANONYMIZED_LINE_NUM)
720 Cow::Owned(line_num.to_string())
726 buffer: &mut StyledBuffer,
734 // Tabs are assumed to have been replaced by spaces in calling code.
735 debug_assert!(!source_string.contains('\t'));
736 let line_len = source_string.len();
737 // Create the source line we will highlight.
738 let left = margin.left(line_len);
739 let right = margin.right(line_len);
740 // On long lines, we strip the source line, accounting for unicode.
742 let code: String = source_string
746 // Make sure that the trimming on the right will fall within the terminal width.
747 // FIXME: `unicode_width` sometimes disagrees with terminals on how wide a `char` is.
748 // For now, just accept that sometimes the code line will be longer than desired.
749 let next = unicode_width::UnicodeWidthChar::width(*ch).unwrap_or(1);
750 if taken + next > right - left {
757 buffer.puts(line_offset, code_offset, &code, Style::Quotation);
758 if margin.was_cut_left() {
759 // We have stripped some code/whitespace from the beginning, make it clear.
760 buffer.puts(line_offset, code_offset, "...", Style::LineNumber);
762 if margin.was_cut_right(line_len) {
763 // We have stripped some code after the right-most span end, make it clear we did so.
764 buffer.puts(line_offset, code_offset + taken - 3, "...", Style::LineNumber);
766 buffer.puts(line_offset, 0, &self.maybe_anonymized(line_index), Style::LineNumber);
768 draw_col_separator_no_space(buffer, line_offset, width_offset - 2);
771 fn render_source_line(
773 buffer: &mut StyledBuffer,
774 file: Lrc<SourceFile>,
779 ) -> Vec<(usize, Style)> {
785 // | secondary span label
787 // ^^ ^ ^^^ ^^^^ ^^^ we don't care about code too far to the right of a span, we trim it
789 // | | | actual code found in your source code and the spans we use to mark it
790 // | | when there's too much wasted space to the left, trim it
791 // | vertical divider between the column number and the code
794 if line.line_index == 0 {
798 let source_string = match file.get_line(line.line_index - 1) {
799 Some(s) => normalize_whitespace(&*s),
800 None => return Vec::new(),
803 let line_offset = buffer.num_lines();
806 let left = margin.left(source_string.len());
808 // Account for unicode characters of width !=0 that were removed.
809 let left = source_string
812 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
825 // Special case when there's only one annotation involved, it is the start of a multiline
826 // span and there's no text at the beginning of the code line. Instead of doing the whole
835 // we simplify the output to:
841 if let [ann] = &line.annotations[..] {
842 if let AnnotationType::MultilineStart(depth) = ann.annotation_type {
843 if source_string.chars().take(ann.start_col).all(|c| c.is_whitespace()) {
844 let style = if ann.is_primary {
845 Style::UnderlinePrimary
847 Style::UnderlineSecondary
849 buffer.putc(line_offset, width_offset + depth - 1, '/', style);
850 return vec![(depth, style)];
855 // We want to display like this:
857 // vec.push(vec.pop().unwrap());
858 // --- ^^^ - previous borrow ends here
860 // | error occurs here
861 // previous borrow of `vec` occurs here
863 // But there are some weird edge cases to be aware of:
865 // vec.push(vec.pop().unwrap());
866 // -------- - previous borrow ends here
868 // |this makes no sense
869 // previous borrow of `vec` occurs here
871 // For this reason, we group the lines into "highlight lines"
872 // and "annotations lines", where the highlight lines have the `^`.
874 // Sort the annotations by (start, end col)
875 // The labels are reversed, sort and then reversed again.
876 // Consider a list of annotations (A1, A2, C1, C2, B1, B2) where
877 // the letter signifies the span. Here we are only sorting by the
878 // span and hence, the order of the elements with the same span will
879 // not change. On reversing the ordering (|a, b| but b.cmp(a)), you get
880 // (C1, C2, B1, B2, A1, A2). All the elements with the same span are
881 // still ordered first to last, but all the elements with different
882 // spans are ordered by their spans in last to first order. Last to
883 // first order is important, because the jiggly lines and | are on
884 // the left, so the rightmost span needs to be rendered first,
885 // otherwise the lines would end up needing to go over a message.
887 let mut annotations = line.annotations.clone();
888 annotations.sort_by_key(|a| Reverse(a.start_col));
890 // First, figure out where each label will be positioned.
892 // In the case where you have the following annotations:
894 // vec.push(vec.pop().unwrap());
895 // -------- - previous borrow ends here [C]
897 // |this makes no sense [B]
898 // previous borrow of `vec` occurs here [A]
900 // `annotations_position` will hold [(2, A), (1, B), (0, C)].
902 // We try, when possible, to stick the rightmost annotation at the end
903 // of the highlight line:
905 // vec.push(vec.pop().unwrap());
906 // --- --- - previous borrow ends here
908 // But sometimes that's not possible because one of the other
909 // annotations overlaps it. For example, from the test
910 // `span_overlap_label`, we have the following annotations
911 // (written on distinct lines for clarity):
917 // In this case, we can't stick the rightmost-most label on
918 // the highlight line, or we would get:
925 // which is totally weird. Instead we want:
933 // which is...less weird, at least. In fact, in general, if
934 // the rightmost span overlaps with any other span, we should
935 // use the "hang below" version, so we can at least make it
936 // clear where the span *starts*. There's an exception for this
937 // logic, when the labels do not have a message:
952 let mut annotations_position = vec![];
953 let mut line_len = 0;
955 for (i, annotation) in annotations.iter().enumerate() {
956 for (j, next) in annotations.iter().enumerate() {
957 if overlaps(next, annotation, 0) // This label overlaps with another one and both
958 && annotation.has_label() // take space (they have text and are not
959 && j > i // multiline lines).
961 // We're currently on the first line, move the label one line down
963 // If we're overlapping with an un-labelled annotation with the same span
964 // we can just merge them in the output
965 if next.start_col == annotation.start_col
966 && next.end_col == annotation.end_col
972 // This annotation needs a new line in the output.
977 annotations_position.push((p, annotation));
978 for (j, next) in annotations.iter().enumerate() {
980 let l = next.label.as_ref().map_or(0, |label| label.len() + 2);
981 if (overlaps(next, annotation, l) // Do not allow two labels to be in the same
982 // line if they overlap including padding, to
983 // avoid situations like:
990 && annotation.has_label() // Both labels must have some text, otherwise
991 && next.has_label()) // they are not overlapping.
992 // Do not add a new line if this annotation
993 // or the next are vertical line placeholders.
994 || (annotation.takes_space() // If either this or the next annotation is
995 && next.has_label()) // multiline start/end, move it to a new line
996 || (annotation.has_label() // so as not to overlap the horizontal lines.
997 && next.takes_space())
998 || (annotation.takes_space() && next.takes_space())
999 || (overlaps(next, annotation, l)
1000 && next.end_col <= annotation.end_col
1005 // This annotation needs a new line in the output.
1011 line_len = max(line_len, p);
1018 // If there are no annotations or the only annotations on this line are
1019 // MultilineLine, then there's only code being shown, stop processing.
1020 if line.annotations.iter().all(|a| a.is_line()) {
1024 // Write the column separator.
1026 // After this we will have:
1035 for pos in 0..=line_len {
1036 draw_col_separator(buffer, line_offset + pos + 1, width_offset - 2);
1039 // Write the horizontal lines for multiline annotations
1040 // (only the first and last lines need this).
1042 // After this we will have:
1051 for &(pos, annotation) in &annotations_position {
1052 let style = if annotation.is_primary {
1053 Style::UnderlinePrimary
1055 Style::UnderlineSecondary
1058 match annotation.annotation_type {
1059 AnnotationType::MultilineStart(depth) | AnnotationType::MultilineEnd(depth) => {
1064 width_offset + depth,
1065 (code_offset + annotation.start_col).saturating_sub(left),
1069 _ if self.teach => {
1070 buffer.set_style_range(
1072 (code_offset + annotation.start_col).saturating_sub(left),
1073 (code_offset + annotation.end_col).saturating_sub(left),
1075 annotation.is_primary,
1082 // Write the vertical lines for labels that are on a different line as the underline.
1084 // After this we will have:
1093 for &(pos, annotation) in &annotations_position {
1094 let style = if annotation.is_primary {
1095 Style::UnderlinePrimary
1097 Style::UnderlineSecondary
1101 if pos > 1 && (annotation.has_label() || annotation.takes_space()) {
1102 for p in line_offset + 1..=line_offset + pos {
1105 (code_offset + annotation.start_col).saturating_sub(left),
1111 match annotation.annotation_type {
1112 AnnotationType::MultilineStart(depth) => {
1113 for p in line_offset + pos + 1..line_offset + line_len + 2 {
1114 buffer.putc(p, width_offset + depth - 1, '|', style);
1117 AnnotationType::MultilineEnd(depth) => {
1118 for p in line_offset..=line_offset + pos {
1119 buffer.putc(p, width_offset + depth - 1, '|', style);
1126 // Write the labels on the annotations that actually have a label.
1128 // After this we will have:
1133 // | something about `foo`
1137 for &(pos, annotation) in &annotations_position {
1139 if annotation.is_primary { Style::LabelPrimary } else { Style::LabelSecondary };
1140 let (pos, col) = if pos == 0 {
1141 (pos + 1, (annotation.end_col + 1).saturating_sub(left))
1143 (pos + 2, annotation.start_col.saturating_sub(left))
1145 if let Some(ref label) = annotation.label {
1146 buffer.puts(line_offset + pos, code_offset + col, &label, style);
1150 // Sort from biggest span to smallest span so that smaller spans are
1151 // represented in the output:
1156 // | | something about `foo`
1157 // | something about `fn foo()`
1158 annotations_position.sort_by_key(|(_, ann)| {
1159 // Decreasing order. When annotations share the same length, prefer `Primary`.
1160 (Reverse(ann.len()), ann.is_primary)
1163 // Write the underlines.
1165 // After this we will have:
1170 // | something about `foo`
1174 for &(_, annotation) in &annotations_position {
1175 let (underline, style) = if annotation.is_primary {
1176 ('^', Style::UnderlinePrimary)
1178 ('-', Style::UnderlineSecondary)
1180 for p in annotation.start_col..annotation.end_col {
1183 (code_offset + p).saturating_sub(left),
1189 annotations_position
1191 .filter_map(|&(_, annotation)| match annotation.annotation_type {
1192 AnnotationType::MultilineStart(p) | AnnotationType::MultilineEnd(p) => {
1193 let style = if annotation.is_primary {
1196 Style::LabelSecondary
1202 .collect::<Vec<_>>()
1205 fn get_multispan_max_line_num(&mut self, msp: &MultiSpan) -> usize {
1206 let Some(ref sm) = self.sm else {
1210 let will_be_emitted = |span: Span| {
1211 !span.is_dummy() && {
1212 let file = sm.lookup_source_file(span.hi());
1213 sm.ensure_source_file_source_present(file)
1218 for primary_span in msp.primary_spans() {
1219 if will_be_emitted(*primary_span) {
1220 let hi = sm.lookup_char_pos(primary_span.hi());
1221 max = (hi.line).max(max);
1224 if !self.short_message {
1225 for span_label in msp.span_labels() {
1226 if will_be_emitted(span_label.span) {
1227 let hi = sm.lookup_char_pos(span_label.span.hi());
1228 max = (hi.line).max(max);
1236 fn get_max_line_num(&mut self, span: &MultiSpan, children: &[SubDiagnostic]) -> usize {
1237 let primary = self.get_multispan_max_line_num(span);
1240 .map(|sub| self.get_multispan_max_line_num(&sub.span))
1246 /// Adds a left margin to every line but the first, given a padding length and the label being
1247 /// displayed, keeping the provided highlighting.
1250 buffer: &mut StyledBuffer,
1251 msg: &[(DiagnosticMessage, Style)],
1252 args: &FluentArgs<'_>,
1255 override_style: Option<Style>,
1257 // The extra 5 ` ` is padding that's always needed to align to the `note: `:
1260 // --> file.rs:13:20
1265 // = note: multiline
1270 // | | length of label
1272 // `max_line_num_len`
1273 let padding = " ".repeat(padding + label.len() + 5);
1275 /// Returns `override` if it is present and `style` is `NoStyle` or `style` otherwise
1276 fn style_or_override(style: Style, override_: Option<Style>) -> Style {
1277 match (style, override_) {
1278 (Style::NoStyle, Some(override_)) => override_,
1283 let mut line_number = 0;
1285 // Provided the following diagnostic message:
1289 // ("highlighted multiline\nstring to\nsee how it ", Style::NoStyle),
1290 // ("looks", Style::Highlight),
1291 // ("with\nvery ", Style::NoStyle),
1292 // ("weird", Style::Highlight),
1293 // (" formats\n", Style::NoStyle),
1294 // ("see?", Style::Highlight),
1297 // the expected output on a note is (* surround the highlighted text)
1299 // = note: highlighted multiline
1301 // see how it *looks* with
1302 // very *weird* formats
1304 for &(ref text, ref style) in msg.iter() {
1305 let text = self.translate_message(text, args);
1306 let lines = text.split('\n').collect::<Vec<_>>();
1307 if lines.len() > 1 {
1308 for (i, line) in lines.iter().enumerate() {
1311 buffer.append(line_number, &padding, Style::NoStyle);
1313 buffer.append(line_number, line, style_or_override(*style, override_style));
1316 buffer.append(line_number, &text, style_or_override(*style, override_style));
1321 fn emit_message_default(
1324 msg: &[(DiagnosticMessage, Style)],
1325 args: &FluentArgs<'_>,
1326 code: &Option<DiagnosticId>,
1328 max_line_num_len: usize,
1330 ) -> io::Result<()> {
1331 let mut buffer = StyledBuffer::new();
1333 if !msp.has_primary_spans() && !msp.has_span_labels() && is_secondary && !self.short_message
1335 // This is a secondary message with no span info
1336 for _ in 0..max_line_num_len {
1337 buffer.prepend(0, " ", Style::NoStyle);
1339 draw_note_separator(&mut buffer, 0, max_line_num_len + 1);
1340 if *level != Level::FailureNote {
1341 buffer.append(0, level.to_str(), Style::MainHeaderMsg);
1342 buffer.append(0, ": ", Style::NoStyle);
1344 self.msg_to_buffer(&mut buffer, msg, args, max_line_num_len, "note", None);
1346 let mut label_width = 0;
1347 // The failure note level itself does not provide any useful diagnostic information
1348 if *level != Level::FailureNote {
1349 buffer.append(0, level.to_str(), Style::Level(*level));
1350 label_width += level.to_str().len();
1352 // only render error codes, not lint codes
1353 if let Some(DiagnosticId::Error(ref code)) = *code {
1354 buffer.append(0, "[", Style::Level(*level));
1355 buffer.append(0, &code, Style::Level(*level));
1356 buffer.append(0, "]", Style::Level(*level));
1357 label_width += 2 + code.len();
1359 let header_style = if is_secondary { Style::HeaderMsg } else { Style::MainHeaderMsg };
1360 if *level != Level::FailureNote {
1361 buffer.append(0, ": ", header_style);
1364 for &(ref text, _) in msg.iter() {
1365 let text = self.translate_message(text, args);
1366 // Account for newlines to align output to its label.
1367 for (line, text) in normalize_whitespace(&text).lines().enumerate() {
1372 if line == 0 { String::new() } else { " ".repeat(label_width) },
1381 let mut annotated_files = FileWithAnnotatedLines::collect_annotations(self, args, msp);
1383 // Make sure our primary file comes first
1384 let (primary_lo, sm) = if let (Some(sm), Some(ref primary_span)) =
1385 (self.sm.as_ref(), msp.primary_span().as_ref())
1387 if !primary_span.is_dummy() {
1388 (sm.lookup_char_pos(primary_span.lo()), sm)
1390 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1394 // If we don't have span information, emit and exit
1395 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1399 annotated_files.binary_search_by(|x| x.file.name.cmp(&primary_lo.file.name))
1401 annotated_files.swap(0, pos);
1404 // Print out the annotate source lines that correspond with the error
1405 for annotated_file in annotated_files {
1406 // we can't annotate anything if the source is unavailable.
1407 if !sm.ensure_source_file_source_present(annotated_file.file.clone()) {
1411 // print out the span location and spacer before we print the annotated source
1412 // to do this, we need to know if this span will be primary
1413 let is_primary = primary_lo.file.name == annotated_file.file.name;
1415 let loc = primary_lo.clone();
1416 if !self.short_message {
1417 // remember where we are in the output buffer for easy reference
1418 let buffer_msg_line_offset = buffer.num_lines();
1420 buffer.prepend(buffer_msg_line_offset, "--> ", Style::LineNumber);
1422 buffer_msg_line_offset,
1425 sm.filename_for_diagnostics(&loc.file.name),
1426 sm.doctest_offset_line(&loc.file.name, loc.line),
1429 Style::LineAndColumn,
1431 for _ in 0..max_line_num_len {
1432 buffer.prepend(buffer_msg_line_offset, " ", Style::NoStyle);
1439 sm.filename_for_diagnostics(&loc.file.name),
1440 sm.doctest_offset_line(&loc.file.name, loc.line),
1443 Style::LineAndColumn,
1446 } else if !self.short_message {
1447 // remember where we are in the output buffer for easy reference
1448 let buffer_msg_line_offset = buffer.num_lines();
1451 draw_col_separator_no_space(
1453 buffer_msg_line_offset,
1454 max_line_num_len + 1,
1457 // Then, the secondary file indicator
1458 buffer.prepend(buffer_msg_line_offset + 1, "::: ", Style::LineNumber);
1459 let loc = if let Some(first_line) = annotated_file.lines.first() {
1460 let col = if let Some(first_annotation) = first_line.annotations.first() {
1461 format!(":{}", first_annotation.start_col + 1)
1467 sm.filename_for_diagnostics(&annotated_file.file.name),
1468 sm.doctest_offset_line(&annotated_file.file.name, first_line.line_index),
1472 format!("{}", sm.filename_for_diagnostics(&annotated_file.file.name))
1474 buffer.append(buffer_msg_line_offset + 1, &loc, Style::LineAndColumn);
1475 for _ in 0..max_line_num_len {
1476 buffer.prepend(buffer_msg_line_offset + 1, " ", Style::NoStyle);
1480 if !self.short_message {
1481 // Put in the spacer between the location and annotated source
1482 let buffer_msg_line_offset = buffer.num_lines();
1483 draw_col_separator_no_space(
1485 buffer_msg_line_offset,
1486 max_line_num_len + 1,
1489 // Contains the vertical lines' positions for active multiline annotations
1490 let mut multilines = FxIndexMap::default();
1492 // Get the left-side margin to remove it
1493 let mut whitespace_margin = usize::MAX;
1494 for line_idx in 0..annotated_file.lines.len() {
1495 let file = annotated_file.file.clone();
1496 let line = &annotated_file.lines[line_idx];
1497 if let Some(source_string) = file.get_line(line.line_index - 1) {
1498 let leading_whitespace = source_string
1500 .take_while(|c| c.is_whitespace())
1503 // Tabs are displayed as 4 spaces
1509 if source_string.chars().any(|c| !c.is_whitespace()) {
1510 whitespace_margin = min(whitespace_margin, leading_whitespace);
1514 if whitespace_margin == usize::MAX {
1515 whitespace_margin = 0;
1518 // Left-most column any visible span points at.
1519 let mut span_left_margin = usize::MAX;
1520 for line in &annotated_file.lines {
1521 for ann in &line.annotations {
1522 span_left_margin = min(span_left_margin, ann.start_col);
1523 span_left_margin = min(span_left_margin, ann.end_col);
1526 if span_left_margin == usize::MAX {
1527 span_left_margin = 0;
1530 // Right-most column any visible span points at.
1531 let mut span_right_margin = 0;
1532 let mut label_right_margin = 0;
1533 let mut max_line_len = 0;
1534 for line in &annotated_file.lines {
1537 annotated_file.file.get_line(line.line_index - 1).map_or(0, |s| s.len()),
1539 for ann in &line.annotations {
1540 span_right_margin = max(span_right_margin, ann.start_col);
1541 span_right_margin = max(span_right_margin, ann.end_col);
1542 // FIXME: account for labels not in the same line
1543 let label_right = ann.label.as_ref().map_or(0, |l| l.len() + 1);
1544 label_right_margin = max(label_right_margin, ann.end_col + label_right);
1548 let width_offset = 3 + max_line_num_len;
1549 let code_offset = if annotated_file.multiline_depth == 0 {
1552 width_offset + annotated_file.multiline_depth + 1
1555 let column_width = if let Some(width) = self.diagnostic_width {
1556 width.saturating_sub(code_offset)
1557 } else if self.ui_testing {
1558 DEFAULT_COLUMN_WIDTH
1560 termize::dimensions()
1561 .map(|(w, _)| w.saturating_sub(code_offset))
1562 .unwrap_or(DEFAULT_COLUMN_WIDTH)
1565 let margin = Margin::new(
1574 // Next, output the annotate source for this file
1575 for line_idx in 0..annotated_file.lines.len() {
1576 let previous_buffer_line = buffer.num_lines();
1578 let depths = self.render_source_line(
1580 annotated_file.file.clone(),
1581 &annotated_file.lines[line_idx],
1587 let mut to_add = FxHashMap::default();
1589 for (depth, style) in depths {
1590 if multilines.remove(&depth).is_none() {
1591 to_add.insert(depth, style);
1595 // Set the multiline annotation vertical lines to the left of
1596 // the code in this line.
1597 for (depth, style) in &multilines {
1598 for line in previous_buffer_line..buffer.num_lines() {
1599 draw_multiline_line(&mut buffer, line, width_offset, *depth, *style);
1602 // check to see if we need to print out or elide lines that come between
1603 // this annotated line and the next one.
1604 if line_idx < (annotated_file.lines.len() - 1) {
1605 let line_idx_delta = annotated_file.lines[line_idx + 1].line_index
1606 - annotated_file.lines[line_idx].line_index;
1607 if line_idx_delta > 2 {
1608 let last_buffer_line_num = buffer.num_lines();
1609 buffer.puts(last_buffer_line_num, 0, "...", Style::LineNumber);
1611 // Set the multiline annotation vertical lines on `...` bridging line.
1612 for (depth, style) in &multilines {
1613 draw_multiline_line(
1615 last_buffer_line_num,
1621 } else if line_idx_delta == 2 {
1622 let unannotated_line = annotated_file
1624 .get_line(annotated_file.lines[line_idx].line_index)
1625 .unwrap_or_else(|| Cow::from(""));
1627 let last_buffer_line_num = buffer.num_lines();
1631 &normalize_whitespace(&unannotated_line),
1632 annotated_file.lines[line_idx + 1].line_index - 1,
1633 last_buffer_line_num,
1639 for (depth, style) in &multilines {
1640 draw_multiline_line(
1642 last_buffer_line_num,
1651 multilines.extend(&to_add);
1656 // final step: take our styled buffer, render it, then output it
1657 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1662 fn emit_suggestion_default(
1665 suggestion: &CodeSuggestion,
1666 args: &FluentArgs<'_>,
1668 max_line_num_len: usize,
1669 ) -> io::Result<()> {
1670 let Some(ref sm) = self.sm else {
1674 // Render the replacements for each suggestion
1675 let suggestions = suggestion.splice_lines(&**sm);
1676 debug!("emit_suggestion_default: suggestions={:?}", suggestions);
1678 if suggestions.is_empty() {
1679 // Suggestions coming from macros can have malformed spans. This is a heavy handed
1680 // approach to avoid ICEs by ignoring the suggestion outright.
1684 let mut buffer = StyledBuffer::new();
1686 // Render the suggestion message
1687 buffer.append(0, level.to_str(), Style::Level(*level));
1688 buffer.append(0, ": ", Style::HeaderMsg);
1692 &[(suggestion.msg.to_owned(), Style::NoStyle)],
1696 Some(Style::HeaderMsg),
1699 let mut row_num = 2;
1700 draw_col_separator_no_space(&mut buffer, 1, max_line_num_len + 1);
1701 let mut notice_capitalization = false;
1702 for (complete, parts, highlights, only_capitalization) in
1703 suggestions.iter().take(MAX_SUGGESTIONS)
1705 notice_capitalization |= only_capitalization;
1707 let has_deletion = parts.iter().any(|p| p.is_deletion(sm));
1708 let is_multiline = complete.lines().count() > 1;
1710 if let Some(span) = span.primary_span() {
1711 // Compare the primary span of the diagnostic with the span of the suggestion
1712 // being emitted. If they belong to the same file, we don't *need* to show the
1713 // file name, saving in verbosity, but if it *isn't* we do need it, otherwise we're
1714 // telling users to make a change but not clarifying *where*.
1715 let loc = sm.lookup_char_pos(parts[0].span.lo());
1716 if loc.file.name != sm.span_to_filename(span) && loc.file.name.is_real() {
1717 buffer.puts(row_num - 1, 0, "--> ", Style::LineNumber);
1722 sm.filename_for_diagnostics(&loc.file.name),
1723 sm.doctest_offset_line(&loc.file.name, loc.line),
1726 Style::LineAndColumn,
1728 for _ in 0..max_line_num_len {
1729 buffer.prepend(row_num - 1, " ", Style::NoStyle);
1734 let show_code_change = if has_deletion && !is_multiline {
1735 DisplaySuggestion::Diff
1736 } else if (parts.len() != 1 || parts[0].snippet.trim() != complete.trim())
1739 DisplaySuggestion::Underline
1741 DisplaySuggestion::None
1744 if let DisplaySuggestion::Diff = show_code_change {
1749 .span_to_lines(parts[0].span)
1750 .expect("span_to_lines failed when emitting suggestion");
1752 assert!(!file_lines.lines.is_empty() || parts[0].span.is_dummy());
1754 let line_start = sm.lookup_char_pos(parts[0].span.lo()).line;
1755 draw_col_separator_no_space(&mut buffer, row_num - 1, max_line_num_len + 1);
1756 let mut lines = complete.lines();
1757 if lines.clone().next().is_none() {
1758 // Account for a suggestion to completely remove a line(s) with whitespace (#94192).
1759 let line_end = sm.lookup_char_pos(parts[0].span.hi()).line;
1760 for line in line_start..=line_end {
1762 row_num - 1 + line - line_start,
1764 &self.maybe_anonymized(line),
1768 row_num - 1 + line - line_start,
1769 max_line_num_len + 1,
1774 row_num - 1 + line - line_start,
1775 max_line_num_len + 3,
1776 &normalize_whitespace(&*file_lines.file.get_line(line - 1).unwrap()),
1780 row_num += line_end - line_start;
1782 let mut unhighlighted_lines = Vec::new();
1783 for (line_pos, (line, highlight_parts)) in lines.by_ref().zip(highlights).enumerate() {
1784 debug!(%line_pos, %line, ?highlight_parts);
1786 // Remember lines that are not highlighted to hide them if needed
1787 if highlight_parts.is_empty() {
1788 unhighlighted_lines.push((line_pos, line));
1792 match unhighlighted_lines.len() {
1794 // Since we show first line, "..." line and last line,
1795 // There is no reason to hide if there are 3 or less lines
1796 // (because then we just replace a line with ... which is
1798 n if n <= 3 => unhighlighted_lines.drain(..).for_each(|(p, l)| {
1799 self.draw_code_line(
1812 // Print first unhighlighted line, "..." and last unhighlighted line, like so:
1814 // LL | this line was highlighted
1815 // LL | this line is just for context
1817 // LL | this line is just for context
1818 // LL | this line was highlighted
1820 let last_line = unhighlighted_lines.pop();
1821 let first_line = unhighlighted_lines.drain(..).next();
1823 first_line.map(|(p, l)| {
1824 self.draw_code_line(
1838 buffer.puts(row_num, max_line_num_len - 1, "...", Style::LineNumber);
1841 last_line.map(|(p, l)| {
1842 self.draw_code_line(
1858 self.draw_code_line(
1872 // This offset and the ones below need to be signed to account for replacement code
1873 // that is shorter than the original code.
1874 let mut offsets: Vec<(usize, isize)> = Vec::new();
1875 // Only show an underline in the suggestions if the suggestion is not the
1876 // entirety of the code being shown and the displayed code is not multiline.
1877 if let DisplaySuggestion::Diff | DisplaySuggestion::Underline = show_code_change {
1878 draw_col_separator_no_space(&mut buffer, row_num, max_line_num_len + 1);
1880 let span_start_pos = sm.lookup_char_pos(part.span.lo()).col_display;
1881 let span_end_pos = sm.lookup_char_pos(part.span.hi()).col_display;
1883 // If this addition is _only_ whitespace, then don't trim it,
1884 // or else we're just not rendering anything.
1885 let is_whitespace_addition = part.snippet.trim().is_empty();
1887 // Do not underline the leading...
1888 let start = if is_whitespace_addition {
1891 part.snippet.len().saturating_sub(part.snippet.trim_start().len())
1893 // ...or trailing spaces. Account for substitutions containing unicode
1895 let sub_len: usize =
1896 if is_whitespace_addition { &part.snippet } else { part.snippet.trim() }
1898 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
1901 let offset: isize = offsets
1904 |(start, v)| if span_start_pos <= *start { None } else { Some(v) },
1907 let underline_start = (span_start_pos + start) as isize + offset;
1908 let underline_end = (span_start_pos + start + sub_len) as isize + offset;
1909 assert!(underline_start >= 0 && underline_end >= 0);
1910 let padding: usize = max_line_num_len + 3;
1911 for p in underline_start..underline_end {
1912 if let DisplaySuggestion::Underline = show_code_change {
1913 // If this is a replacement, underline with `^`, if this is an addition
1914 // underline with `+`.
1917 (padding as isize + p) as usize,
1918 if part.is_addition(&sm) { '+' } else { '~' },
1923 if let DisplaySuggestion::Diff = show_code_change {
1924 // Colorize removal with red in diff format.
1925 buffer.set_style_range(
1927 (padding as isize + span_start_pos as isize) as usize,
1928 (padding as isize + span_end_pos as isize) as usize,
1934 // length of the code after substitution
1935 let full_sub_len = part
1938 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
1939 .sum::<usize>() as isize;
1941 // length of the code to be substituted
1942 let snippet_len = span_end_pos as isize - span_start_pos as isize;
1943 // For multiple substitutions, use the position *after* the previous
1944 // substitutions have happened, only when further substitutions are
1945 // located strictly after.
1946 offsets.push((span_end_pos, full_sub_len - snippet_len));
1951 // if we elided some lines, add an ellipsis
1952 if lines.next().is_some() {
1953 buffer.puts(row_num, max_line_num_len - 1, "...", Style::LineNumber);
1954 } else if let DisplaySuggestion::None = show_code_change {
1955 draw_col_separator_no_space(&mut buffer, row_num, max_line_num_len + 1);
1959 if suggestions.len() > MAX_SUGGESTIONS {
1960 let others = suggestions.len() - MAX_SUGGESTIONS;
1961 let msg = format!("and {} other candidate{}", others, pluralize!(others));
1962 buffer.puts(row_num, max_line_num_len + 3, &msg, Style::NoStyle);
1963 } else if notice_capitalization {
1964 let msg = "notice the capitalization difference";
1965 buffer.puts(row_num, max_line_num_len + 3, &msg, Style::NoStyle);
1967 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1971 fn emit_messages_default(
1974 message: &[(DiagnosticMessage, Style)],
1975 args: &FluentArgs<'_>,
1976 code: &Option<DiagnosticId>,
1978 children: &[SubDiagnostic],
1979 suggestions: &[CodeSuggestion],
1981 let max_line_num_len = if self.ui_testing {
1982 ANONYMIZED_LINE_NUM.len()
1984 let n = self.get_max_line_num(span, children);
1985 num_decimal_digits(n)
1988 match self.emit_message_default(span, message, args, code, level, max_line_num_len, false) {
1990 if !children.is_empty()
1991 || suggestions.iter().any(|s| s.style != SuggestionStyle::CompletelyHidden)
1993 let mut buffer = StyledBuffer::new();
1994 if !self.short_message {
1995 draw_col_separator_no_space(&mut buffer, 0, max_line_num_len + 1);
1997 if let Err(e) = emit_to_destination(
2003 panic!("failed to emit error: {}", e)
2006 if !self.short_message {
2007 for child in children {
2008 let span = child.render_span.as_ref().unwrap_or(&child.span);
2009 if let Err(err) = self.emit_message_default(
2018 panic!("failed to emit error: {}", err);
2021 for sugg in suggestions {
2022 if sugg.style == SuggestionStyle::CompletelyHidden {
2023 // do not display this suggestion, it is meant only for tools
2024 } else if sugg.style == SuggestionStyle::HideCodeAlways {
2025 if let Err(e) = self.emit_message_default(
2027 &[(sugg.msg.to_owned(), Style::HeaderMsg)],
2034 panic!("failed to emit error: {}", e);
2036 } else if let Err(e) = self.emit_suggestion_default(
2043 panic!("failed to emit error: {}", e);
2048 Err(e) => panic!("failed to emit error: {}", e),
2051 let mut dst = self.dst.writable();
2052 match writeln!(dst) {
2053 Err(e) => panic!("failed to emit error: {}", e),
2055 if let Err(e) = dst.flush() {
2056 panic!("failed to emit error: {}", e)
2064 buffer: &mut StyledBuffer,
2065 row_num: &mut usize,
2066 highlight_parts: &Vec<SubstitutionHighlight>,
2070 show_code_change: DisplaySuggestion,
2071 max_line_num_len: usize,
2072 file_lines: &FileLines,
2075 // Print the span column to avoid confusion
2076 buffer.puts(*row_num, 0, &self.maybe_anonymized(line_start + line_pos), Style::LineNumber);
2077 if let DisplaySuggestion::Diff = show_code_change {
2078 // Add the line number for both addition and removal to drive the point home.
2080 // N - fn foo<A: T>(bar: A) {
2081 // N + fn foo(bar: impl T) {
2085 &self.maybe_anonymized(line_start + line_pos),
2088 buffer.puts(*row_num - 1, max_line_num_len + 1, "- ", Style::Removal);
2091 max_line_num_len + 3,
2092 &normalize_whitespace(
2093 &*file_lines.file.get_line(file_lines.lines[line_pos].line_index).unwrap(),
2097 buffer.puts(*row_num, max_line_num_len + 1, "+ ", Style::Addition);
2098 } else if is_multiline {
2099 match &highlight_parts[..] {
2100 [SubstitutionHighlight { start: 0, end }] if *end == line.len() => {
2101 buffer.puts(*row_num, max_line_num_len + 1, "+ ", Style::Addition);
2104 draw_col_separator(buffer, *row_num, max_line_num_len + 1);
2107 buffer.puts(*row_num, max_line_num_len + 1, "~ ", Style::Addition);
2111 draw_col_separator(buffer, *row_num, max_line_num_len + 1);
2114 // print the suggestion
2115 buffer.append(*row_num, &normalize_whitespace(line), Style::NoStyle);
2117 // Colorize addition/replacements with green.
2118 for &SubstitutionHighlight { start, end } in highlight_parts {
2119 // Account for tabs when highlighting (#87972).
2120 let tabs: usize = line
2123 .map(|ch| match ch {
2128 buffer.set_style_range(
2130 max_line_num_len + 3 + start + tabs,
2131 max_line_num_len + 3 + end + tabs,
2140 #[derive(Clone, Copy, Debug)]
2141 enum DisplaySuggestion {
2147 impl FileWithAnnotatedLines {
2148 /// Preprocess all the annotations so that they are grouped by file and by line number
2149 /// This helps us quickly iterate over the whole message (including secondary file spans)
2150 pub fn collect_annotations(
2151 emitter: &dyn Emitter,
2152 args: &FluentArgs<'_>,
2154 ) -> Vec<FileWithAnnotatedLines> {
2155 fn add_annotation_to_file(
2156 file_vec: &mut Vec<FileWithAnnotatedLines>,
2157 file: Lrc<SourceFile>,
2161 for slot in file_vec.iter_mut() {
2162 // Look through each of our files for the one we're adding to
2163 if slot.file.name == file.name {
2164 // See if we already have a line for it
2165 for line_slot in &mut slot.lines {
2166 if line_slot.line_index == line_index {
2167 line_slot.annotations.push(ann);
2171 // We don't have a line yet, create one
2172 slot.lines.push(Line { line_index, annotations: vec![ann] });
2177 // This is the first time we're seeing the file
2178 file_vec.push(FileWithAnnotatedLines {
2180 lines: vec![Line { line_index, annotations: vec![ann] }],
2185 let mut output = vec![];
2186 let mut multiline_annotations = vec![];
2188 if let Some(ref sm) = emitter.source_map() {
2189 for span_label in msp.span_labels() {
2190 if span_label.span.is_dummy() {
2194 let lo = sm.lookup_char_pos(span_label.span.lo());
2195 let mut hi = sm.lookup_char_pos(span_label.span.hi());
2197 // Watch out for "empty spans". If we get a span like 6..6, we
2198 // want to just display a `^` at 6, so convert that to
2199 // 6..7. This is degenerate input, but it's best to degrade
2200 // gracefully -- and the parser likes to supply a span like
2201 // that for EOF, in particular.
2203 if lo.col_display == hi.col_display && lo.line == hi.line {
2204 hi.col_display += 1;
2207 if lo.line != hi.line {
2208 let ml = MultilineAnnotation {
2210 line_start: lo.line,
2212 start_col: lo.col_display,
2213 end_col: hi.col_display,
2214 is_primary: span_label.is_primary,
2218 .map(|m| emitter.translate_message(m, args).to_string()),
2219 overlaps_exactly: false,
2221 multiline_annotations.push((lo.file, ml));
2223 let ann = Annotation {
2224 start_col: lo.col_display,
2225 end_col: hi.col_display,
2226 is_primary: span_label.is_primary,
2230 .map(|m| emitter.translate_message(m, args).to_string()),
2231 annotation_type: AnnotationType::Singleline,
2233 add_annotation_to_file(&mut output, lo.file, lo.line, ann);
2238 // Find overlapping multiline annotations, put them at different depths
2239 multiline_annotations.sort_by_key(|&(_, ref ml)| (ml.line_start, ml.line_end));
2240 for (_, ann) in multiline_annotations.clone() {
2241 for (_, a) in multiline_annotations.iter_mut() {
2242 // Move all other multiline annotations overlapping with this one
2243 // one level to the right.
2244 if !(ann.same_span(a))
2245 && num_overlap(ann.line_start, ann.line_end, a.line_start, a.line_end, true)
2248 } else if ann.same_span(a) && &ann != a {
2249 a.overlaps_exactly = true;
2256 let mut max_depth = 0; // max overlapping multiline spans
2257 for (file, ann) in multiline_annotations {
2258 max_depth = max(max_depth, ann.depth);
2259 let mut end_ann = ann.as_end();
2260 if !ann.overlaps_exactly {
2261 // avoid output like
2283 add_annotation_to_file(&mut output, file.clone(), ann.line_start, ann.as_start());
2284 // 4 is the minimum vertical length of a multiline span when presented: two lines
2285 // of code and two lines of underline. This is not true for the special case where
2286 // the beginning doesn't have an underline, but the current logic seems to be
2287 // working correctly.
2288 let middle = min(ann.line_start + 4, ann.line_end);
2289 for line in ann.line_start + 1..middle {
2290 // Every `|` that joins the beginning of the span (`___^`) to the end (`|__^`).
2291 add_annotation_to_file(&mut output, file.clone(), line, ann.as_line());
2293 let line_end = ann.line_end - 1;
2294 if middle < line_end {
2295 add_annotation_to_file(&mut output, file.clone(), line_end, ann.as_line());
2298 end_ann.annotation_type = AnnotationType::Singleline;
2300 add_annotation_to_file(&mut output, file, ann.line_end, end_ann);
2302 for file_vec in output.iter_mut() {
2303 file_vec.multiline_depth = max_depth;
2309 // instead of taking the String length or dividing by 10 while > 0, we multiply a limit by 10 until
2310 // we're higher. If the loop isn't exited by the `return`, the last multiplication will wrap, which
2311 // is OK, because while we cannot fit a higher power of 10 in a usize, the loop will end anyway.
2312 // This is also why we need the max number of decimal digits within a `usize`.
2313 fn num_decimal_digits(num: usize) -> usize {
2314 #[cfg(target_pointer_width = "64")]
2315 const MAX_DIGITS: usize = 20;
2317 #[cfg(target_pointer_width = "32")]
2318 const MAX_DIGITS: usize = 10;
2320 #[cfg(target_pointer_width = "16")]
2321 const MAX_DIGITS: usize = 5;
2324 for num_digits in 1..MAX_DIGITS {
2328 lim = lim.wrapping_mul(10);
2333 // We replace some characters so the CLI output is always consistent and underlines aligned.
2334 const OUTPUT_REPLACEMENTS: &[(char, &str)] = &[
2335 ('\t', " "), // We do our own tab replacement
2336 ('\u{200D}', ""), // Replace ZWJ with nothing for consistent terminal output of grapheme clusters.
2337 ('\u{202A}', ""), // The following unicode text flow control characters are inconsistently
2338 ('\u{202B}', ""), // supported across CLIs and can cause confusion due to the bytes on disk
2339 ('\u{202D}', ""), // not corresponding to the visible source code, so we replace them always.
2348 fn normalize_whitespace(str: &str) -> String {
2349 let mut s = str.to_string();
2350 for (c, replacement) in OUTPUT_REPLACEMENTS {
2351 s = s.replace(*c, replacement);
2356 fn draw_col_separator(buffer: &mut StyledBuffer, line: usize, col: usize) {
2357 buffer.puts(line, col, "| ", Style::LineNumber);
2360 fn draw_col_separator_no_space(buffer: &mut StyledBuffer, line: usize, col: usize) {
2361 draw_col_separator_no_space_with_style(buffer, line, col, Style::LineNumber);
2364 fn draw_col_separator_no_space_with_style(
2365 buffer: &mut StyledBuffer,
2370 buffer.putc(line, col, '|', style);
2374 buffer: &mut StyledBuffer,
2381 for col in col_from..col_to {
2382 buffer.putc(line, col, symbol, style);
2386 fn draw_note_separator(buffer: &mut StyledBuffer, line: usize, col: usize) {
2387 buffer.puts(line, col, "= ", Style::LineNumber);
2390 fn draw_multiline_line(
2391 buffer: &mut StyledBuffer,
2397 buffer.putc(line, offset + depth - 1, '|', style);
2407 let extra = if inclusive { 1 } else { 0 };
2408 (b_start..b_end + extra).contains(&a_start) || (a_start..a_end + extra).contains(&b_start)
2410 fn overlaps(a1: &Annotation, a2: &Annotation, padding: usize) -> bool {
2411 num_overlap(a1.start_col, a1.end_col + padding, a2.start_col, a2.end_col, false)
2414 fn emit_to_destination(
2415 rendered_buffer: &[Vec<StyledString>],
2417 dst: &mut Destination,
2418 short_message: bool,
2419 ) -> io::Result<()> {
2422 let mut dst = dst.writable();
2424 // In order to prevent error message interleaving, where multiple error lines get intermixed
2425 // when multiple compiler processes error simultaneously, we emit errors with additional
2428 // On Unix systems, we write into a buffered terminal rather than directly to a terminal. When
2429 // the .flush() is called we take the buffer created from the buffered writes and write it at
2430 // one shot. Because the Unix systems use ANSI for the colors, which is a text-based styling
2431 // scheme, this buffered approach works and maintains the styling.
2433 // On Windows, styling happens through calls to a terminal API. This prevents us from using the
2434 // same buffering approach. Instead, we use a global Windows mutex, which we acquire long
2435 // enough to output the full error message, then we release.
2436 let _buffer_lock = lock::acquire_global_lock("rustc_errors");
2437 for (pos, line) in rendered_buffer.iter().enumerate() {
2439 dst.apply_style(*lvl, part.style)?;
2440 write!(dst, "{}", part.text)?;
2443 if !short_message && (!lvl.is_failure_note() || pos != rendered_buffer.len() - 1) {
2451 pub enum Destination {
2452 Terminal(StandardStream),
2453 Buffered(BufferWriter),
2454 // The bool denotes whether we should be emitting ansi color codes or not
2455 Raw(Box<(dyn Write + Send)>, bool),
2458 pub enum WritableDst<'a> {
2459 Terminal(&'a mut StandardStream),
2460 Buffered(&'a mut BufferWriter, Buffer),
2461 Raw(&'a mut (dyn Write + Send)),
2462 ColoredRaw(Ansi<&'a mut (dyn Write + Send)>),
2466 fn from_stderr(color: ColorConfig) -> Destination {
2467 let choice = color.to_color_choice();
2468 // On Windows we'll be performing global synchronization on the entire
2469 // system for emitting rustc errors, so there's no need to buffer
2472 // On non-Windows we rely on the atomicity of `write` to ensure errors
2473 // don't get all jumbled up.
2475 Terminal(StandardStream::stderr(choice))
2477 Buffered(BufferWriter::stderr(choice))
2481 fn writable(&mut self) -> WritableDst<'_> {
2483 Destination::Terminal(ref mut t) => WritableDst::Terminal(t),
2484 Destination::Buffered(ref mut t) => {
2485 let buf = t.buffer();
2486 WritableDst::Buffered(t, buf)
2488 Destination::Raw(ref mut t, false) => WritableDst::Raw(t),
2489 Destination::Raw(ref mut t, true) => WritableDst::ColoredRaw(Ansi::new(t)),
2493 fn supports_color(&self) -> bool {
2495 Self::Terminal(ref stream) => stream.supports_color(),
2496 Self::Buffered(ref buffer) => buffer.buffer().supports_color(),
2497 Self::Raw(_, supports_color) => supports_color,
2502 impl<'a> WritableDst<'a> {
2503 fn apply_style(&mut self, lvl: Level, style: Style) -> io::Result<()> {
2504 let mut spec = ColorSpec::new();
2506 Style::Addition => {
2507 spec.set_fg(Some(Color::Green)).set_intense(true);
2510 spec.set_fg(Some(Color::Red)).set_intense(true);
2512 Style::LineAndColumn => {}
2513 Style::LineNumber => {
2514 spec.set_bold(true);
2515 spec.set_intense(true);
2517 spec.set_fg(Some(Color::Cyan));
2519 spec.set_fg(Some(Color::Blue));
2522 Style::Quotation => {}
2523 Style::MainHeaderMsg => {
2524 spec.set_bold(true);
2526 spec.set_intense(true).set_fg(Some(Color::White));
2529 Style::UnderlinePrimary | Style::LabelPrimary => {
2531 spec.set_bold(true);
2533 Style::UnderlineSecondary | Style::LabelSecondary => {
2534 spec.set_bold(true).set_intense(true);
2536 spec.set_fg(Some(Color::Cyan));
2538 spec.set_fg(Some(Color::Blue));
2541 Style::HeaderMsg | Style::NoStyle => {}
2542 Style::Level(lvl) => {
2544 spec.set_bold(true);
2546 Style::Highlight => {
2547 spec.set_bold(true);
2550 self.set_color(&spec)
2553 fn set_color(&mut self, color: &ColorSpec) -> io::Result<()> {
2555 WritableDst::Terminal(ref mut t) => t.set_color(color),
2556 WritableDst::Buffered(_, ref mut t) => t.set_color(color),
2557 WritableDst::ColoredRaw(ref mut t) => t.set_color(color),
2558 WritableDst::Raw(_) => Ok(()),
2562 fn reset(&mut self) -> io::Result<()> {
2564 WritableDst::Terminal(ref mut t) => t.reset(),
2565 WritableDst::Buffered(_, ref mut t) => t.reset(),
2566 WritableDst::ColoredRaw(ref mut t) => t.reset(),
2567 WritableDst::Raw(_) => Ok(()),
2572 impl<'a> Write for WritableDst<'a> {
2573 fn write(&mut self, bytes: &[u8]) -> io::Result<usize> {
2575 WritableDst::Terminal(ref mut t) => t.write(bytes),
2576 WritableDst::Buffered(_, ref mut buf) => buf.write(bytes),
2577 WritableDst::Raw(ref mut w) => w.write(bytes),
2578 WritableDst::ColoredRaw(ref mut t) => t.write(bytes),
2582 fn flush(&mut self) -> io::Result<()> {
2584 WritableDst::Terminal(ref mut t) => t.flush(),
2585 WritableDst::Buffered(_, ref mut buf) => buf.flush(),
2586 WritableDst::Raw(ref mut w) => w.flush(),
2587 WritableDst::ColoredRaw(ref mut w) => w.flush(),
2592 impl<'a> Drop for WritableDst<'a> {
2593 fn drop(&mut self) {
2594 if let WritableDst::Buffered(ref mut dst, ref mut buf) = self {
2595 drop(dst.print(buf));
2600 /// Whether the original and suggested code are visually similar enough to warrant extra wording.
2601 pub fn is_case_difference(sm: &SourceMap, suggested: &str, sp: Span) -> bool {
2602 // FIXME: this should probably be extended to also account for `FO0` → `FOO` and unicode.
2603 let found = match sm.span_to_snippet(sp) {
2604 Ok(snippet) => snippet,
2606 warn!(error = ?e, "Invalid span {:?}", sp);
2610 let ascii_confusables = &['c', 'f', 'i', 'k', 'o', 's', 'u', 'v', 'w', 'x', 'y', 'z'];
2611 // All the chars that differ in capitalization are confusable (above):
2612 let confusable = iter::zip(found.chars(), suggested.chars())
2613 .filter(|(f, s)| f != s)
2614 .all(|(f, s)| (ascii_confusables.contains(&f) || ascii_confusables.contains(&s)));
2615 confusable && found.to_lowercase() == suggested.to_lowercase()
2616 // FIXME: We sometimes suggest the same thing we already have, which is a
2617 // bug, but be defensive against that here.
2618 && found != suggested