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::{SourceFile, Span};
15 use crate::snippet::{Annotation, AnnotationType, Line, MultilineAnnotation, Style, StyledString};
16 use crate::styled_buffer::StyledBuffer;
18 CodeSuggestion, Diagnostic, DiagnosticArg, DiagnosticId, DiagnosticMessage, FluentBundle,
19 Handler, LazyFallbackBundle, Level, MultiSpan, SubDiagnostic, SubstitutionHighlight,
23 use rustc_lint_defs::pluralize;
25 use rustc_data_structures::fx::FxHashMap;
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};
39 /// Default column width, used in tests and when terminal dimensions cannot be determined.
40 const DEFAULT_COLUMN_WIDTH: usize = 140;
42 /// Describes the way the content of the `rendered` field of the json output is generated
43 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
44 pub enum HumanReadableErrorType {
46 AnnotateSnippet(ColorConfig),
50 impl HumanReadableErrorType {
51 /// Returns a (`short`, `color`) tuple
52 pub fn unzip(self) -> (bool, ColorConfig) {
54 HumanReadableErrorType::Default(cc) => (false, cc),
55 HumanReadableErrorType::Short(cc) => (true, cc),
56 HumanReadableErrorType::AnnotateSnippet(cc) => (false, cc),
61 dst: Box<dyn Write + Send>,
62 source_map: Option<Lrc<SourceMap>>,
63 bundle: Option<Lrc<FluentBundle>>,
64 fallback_bundle: LazyFallbackBundle,
66 terminal_width: Option<usize>,
67 macro_backtrace: bool,
69 let (short, color_config) = self.unzip();
70 let color = color_config.suggests_using_colors();
85 #[derive(Clone, Copy, Debug)]
87 /// The available whitespace in the left that can be consumed when centering.
88 pub whitespace_left: usize,
89 /// The column of the beginning of left-most span.
91 /// The column of the end of right-most span.
92 pub span_right: usize,
93 /// The beginning of the line to be displayed.
94 pub computed_left: usize,
95 /// The end of the line to be displayed.
96 pub computed_right: usize,
97 /// The current width of the terminal. Uses value of `DEFAULT_COLUMN_WIDTH` constant by default
99 pub column_width: usize,
100 /// The end column of a span label, including the span. Doesn't account for labels not in the
101 /// same line as the span.
102 pub label_right: usize,
107 whitespace_left: usize,
114 // The 6 is padding to give a bit of room for `...` when displaying:
119 // 16 | ... fn foo(self) -> Self::Bar {
124 whitespace_left: whitespace_left.saturating_sub(6),
125 span_left: span_left.saturating_sub(6),
126 span_right: span_right + 6,
130 label_right: label_right + 6,
132 m.compute(max_line_len);
136 fn was_cut_left(&self) -> bool {
137 self.computed_left > 0
140 fn was_cut_right(&self, line_len: usize) -> bool {
142 if self.computed_right == self.span_right || self.computed_right == self.label_right {
143 // Account for the "..." padding given above. Otherwise we end up with code lines that
144 // do fit but end in "..." as if they were trimmed.
145 self.computed_right - 6
149 right < line_len && self.computed_left + self.column_width < line_len
152 fn compute(&mut self, max_line_len: usize) {
153 // When there's a lot of whitespace (>20), we want to trim it as it is useless.
154 self.computed_left = if self.whitespace_left > 20 {
155 self.whitespace_left - 16 // We want some padding.
159 // We want to show as much as possible, max_line_len is the right-most boundary for the
161 self.computed_right = max(max_line_len, self.computed_left);
163 if self.computed_right - self.computed_left > self.column_width {
164 // Trimming only whitespace isn't enough, let's get craftier.
165 if self.label_right - self.whitespace_left <= self.column_width {
166 // Attempt to fit the code window only trimming whitespace.
167 self.computed_left = self.whitespace_left;
168 self.computed_right = self.computed_left + self.column_width;
169 } else if self.label_right - self.span_left <= self.column_width {
170 // Attempt to fit the code window considering only the spans and labels.
171 let padding_left = (self.column_width - (self.label_right - self.span_left)) / 2;
172 self.computed_left = self.span_left.saturating_sub(padding_left);
173 self.computed_right = self.computed_left + self.column_width;
174 } else if self.span_right - self.span_left <= self.column_width {
175 // Attempt to fit the code window considering the spans and labels plus padding.
176 let padding_left = (self.column_width - (self.span_right - self.span_left)) / 5 * 2;
177 self.computed_left = self.span_left.saturating_sub(padding_left);
178 self.computed_right = self.computed_left + self.column_width;
180 // Mostly give up but still don't show the full line.
181 self.computed_left = self.span_left;
182 self.computed_right = self.span_right;
187 fn left(&self, line_len: usize) -> usize {
188 min(self.computed_left, line_len)
191 fn right(&self, line_len: usize) -> usize {
192 if line_len.saturating_sub(self.computed_left) <= self.column_width {
195 min(line_len, self.computed_right)
200 const ANONYMIZED_LINE_NUM: &str = "LL";
202 /// Emitter trait for emitting errors.
204 /// Emit a structured diagnostic.
205 fn emit_diagnostic(&mut self, diag: &Diagnostic);
207 /// Emit a notification that an artifact has been output.
208 /// This is currently only supported for the JSON format,
209 /// other formats can, and will, simply ignore it.
210 fn emit_artifact_notification(&mut self, _path: &Path, _artifact_type: &str) {}
212 fn emit_future_breakage_report(&mut self, _diags: Vec<Diagnostic>) {}
214 /// Emit list of unused externs
215 fn emit_unused_externs(
217 _lint_level: rustc_lint_defs::Level,
218 _unused_externs: &[&str],
222 /// Checks if should show explanations about "rustc --explain"
223 fn should_show_explain(&self) -> bool {
227 /// Checks if we can use colors in the current output stream.
228 fn supports_color(&self) -> bool {
232 fn source_map(&self) -> Option<&Lrc<SourceMap>>;
234 /// Return `FluentBundle` with localized diagnostics for the locale requested by the user. If no
235 /// language was requested by the user then this will be `None` and `fallback_fluent_bundle`
237 fn fluent_bundle(&self) -> Option<&Lrc<FluentBundle>>;
239 /// Return `FluentBundle` with localized diagnostics for the default locale of the compiler.
240 /// Used when the user has not requested a specific language or when a localized diagnostic is
241 /// unavailable for the requested locale.
242 fn fallback_fluent_bundle(&self) -> &FluentBundle;
244 /// Convert diagnostic arguments (a rustc internal type that exists to implement
245 /// `Encodable`/`Decodable`) into `FluentArgs` which is necessary to perform translation.
247 /// Typically performed once for each diagnostic at the start of `emit_diagnostic` and then
248 /// passed around as a reference thereafter.
249 fn to_fluent_args<'arg>(&self, args: &[DiagnosticArg<'arg>]) -> FluentArgs<'arg> {
250 FromIterator::from_iter(args.to_vec().drain(..))
253 /// Convert `DiagnosticMessage`s to a string, performing translation if necessary.
254 fn translate_messages(
256 messages: &[(DiagnosticMessage, Style)],
257 args: &FluentArgs<'_>,
260 messages.iter().map(|(m, _)| self.translate_message(m, args)).collect::<String>(),
264 /// Convert a `DiagnosticMessage` to a string, performing translation if necessary.
265 fn translate_message<'a>(
267 message: &'a DiagnosticMessage,
268 args: &'a FluentArgs<'_>,
270 trace!(?message, ?args);
271 let (identifier, attr) = match message {
272 DiagnosticMessage::Str(msg) => return Cow::Borrowed(&msg),
273 DiagnosticMessage::FluentIdentifier(identifier, attr) => (identifier, attr),
276 let bundle = match self.fluent_bundle() {
277 Some(bundle) if bundle.has_message(&identifier) => bundle,
278 _ => self.fallback_fluent_bundle(),
281 let message = bundle.get_message(&identifier).expect("missing diagnostic in fluent bundle");
282 let value = match attr {
284 message.get_attribute(attr).expect("missing attribute in fluent message").value()
286 None => message.value().expect("missing value in fluent message"),
289 let mut err = vec![];
290 let translated = bundle.format_pattern(value, Some(&args), &mut err);
291 trace!(?translated, ?err);
294 "identifier: {:?}, args: {:?}, errors: {:?}",
302 /// Formats the substitutions of the primary_span
304 /// There are a lot of conditions to this method, but in short:
306 /// * If the current `Diagnostic` has only one visible `CodeSuggestion`,
307 /// we format the `help` suggestion depending on the content of the
308 /// substitutions. In that case, we return the modified span only.
310 /// * If the current `Diagnostic` has multiple suggestions,
311 /// we return the original `primary_span` and the original suggestions.
312 fn primary_span_formatted<'a>(
314 diag: &'a Diagnostic,
315 fluent_args: &FluentArgs<'_>,
316 ) -> (MultiSpan, &'a [CodeSuggestion]) {
317 let mut primary_span = diag.span.clone();
318 let suggestions = diag.suggestions.as_ref().map_or(&[][..], |suggestions| &suggestions[..]);
319 if let Some((sugg, rest)) = suggestions.split_first() {
320 let msg = self.translate_message(&sugg.msg, fluent_args);
321 if rest.is_empty() &&
322 // ^ if there is only one suggestion
323 // don't display multi-suggestions as labels
324 sugg.substitutions.len() == 1 &&
325 // don't display multipart suggestions as labels
326 sugg.substitutions[0].parts.len() == 1 &&
327 // don't display long messages as labels
328 msg.split_whitespace().count() < 10 &&
329 // don't display multiline suggestions as labels
330 !sugg.substitutions[0].parts[0].snippet.contains('\n') &&
332 // when this style is set we want the suggestion to be a message, not inline
333 SuggestionStyle::HideCodeAlways,
334 // trivial suggestion for tooling's sake, never shown
335 SuggestionStyle::CompletelyHidden,
336 // subtle suggestion, never shown inline
337 SuggestionStyle::ShowAlways,
338 ].contains(&sugg.style)
340 let substitution = &sugg.substitutions[0].parts[0].snippet.trim();
341 let msg = if substitution.is_empty() || sugg.style.hide_inline() {
342 // This substitution is only removal OR we explicitly don't want to show the
343 // code inline (`hide_inline`). Therefore, we don't show the substitution.
344 format!("help: {}", &msg)
346 // Show the default suggestion text with the substitution
352 .map(|sm| is_case_difference(
355 sugg.substitutions[0].parts[0].span,
359 " (notice the capitalization)"
366 primary_span.push_span_label(sugg.substitutions[0].parts[0].span, msg);
368 // We return only the modified primary_span
371 // if there are multiple suggestions, print them all in full
372 // to be consistent. We could try to figure out if we can
373 // make one (or the first one) inline, but that would give
374 // undue importance to a semi-random suggestion
375 (primary_span, suggestions)
378 (primary_span, suggestions)
382 fn fix_multispans_in_extern_macros_and_render_macro_backtrace(
384 source_map: &Option<Lrc<SourceMap>>,
385 span: &mut MultiSpan,
386 children: &mut Vec<SubDiagnostic>,
390 // Check for spans in macros, before `fix_multispans_in_extern_macros`
391 // has a chance to replace them.
392 let has_macro_spans = iter::once(&*span)
393 .chain(children.iter().map(|child| &child.span))
394 .flat_map(|span| span.primary_spans())
395 .flat_map(|sp| sp.macro_backtrace())
396 .find_map(|expn_data| {
397 match expn_data.kind {
398 ExpnKind::Root => None,
400 // Skip past non-macro entries, just in case there
401 // are some which do actually involve macros.
402 ExpnKind::Inlined | ExpnKind::Desugaring(..) | ExpnKind::AstPass(..) => None,
404 ExpnKind::Macro(macro_kind, name) => Some((macro_kind, name)),
409 self.fix_multispans_in_extern_macros(source_map, span, children);
412 self.render_multispans_macro_backtrace(span, children, backtrace);
415 if let Some((macro_kind, name)) = has_macro_spans {
416 let descr = macro_kind.descr();
419 "this {level} originates in the {descr} `{name}` \
420 (in Nightly builds, run with -Z macro-backtrace for more info)",
423 children.push(SubDiagnostic {
425 message: vec![(DiagnosticMessage::Str(msg), Style::NoStyle)],
426 span: MultiSpan::new(),
433 fn render_multispans_macro_backtrace(
435 span: &mut MultiSpan,
436 children: &mut Vec<SubDiagnostic>,
439 for span in iter::once(span).chain(children.iter_mut().map(|child| &mut child.span)) {
440 self.render_multispan_macro_backtrace(span, backtrace);
444 fn render_multispan_macro_backtrace(&self, span: &mut MultiSpan, always_backtrace: bool) {
445 let mut new_labels: Vec<(Span, String)> = vec![];
447 for &sp in span.primary_spans() {
452 // FIXME(eddyb) use `retain` on `macro_backtrace` to remove all the
453 // entries we don't want to print, to make sure the indices being
454 // printed are contiguous (or omitted if there's only one entry).
455 let macro_backtrace: Vec<_> = sp.macro_backtrace().collect();
456 for (i, trace) in macro_backtrace.iter().rev().enumerate() {
457 if trace.def_site.is_dummy() {
461 if always_backtrace && !matches!(trace.kind, ExpnKind::Inlined) {
465 "in this expansion of `{}`{}",
467 if macro_backtrace.len() > 1 {
468 // if macro_backtrace.len() == 1 it'll be
469 // pointed at by "in this macro invocation"
470 format!(" (#{})", i + 1)
478 // Don't add a label on the call site if the diagnostic itself
479 // already points to (a part of) that call site, as the label
480 // is meant for showing the relevant invocation when the actual
481 // diagnostic is pointing to some part of macro definition.
483 // This also handles the case where an external span got replaced
484 // with the call site span by `fix_multispans_in_extern_macros`.
486 // NB: `-Zmacro-backtrace` overrides this, for uniformity, as the
487 // "in this expansion of" label above is always added in that mode,
488 // and it needs an "in this macro invocation" label to match that.
489 let redundant_span = trace.call_site.contains(sp);
491 if !redundant_span || always_backtrace {
492 let msg: Cow<'static, _> = match trace.kind {
493 ExpnKind::Macro(MacroKind::Attr, _) => {
494 "this procedural macro expansion".into()
496 ExpnKind::Macro(MacroKind::Derive, _) => {
497 "this derive macro expansion".into()
499 ExpnKind::Macro(MacroKind::Bang, _) => "this macro invocation".into(),
500 ExpnKind::Inlined => "this inlined function call".into(),
501 ExpnKind::Root => "the crate root".into(),
502 ExpnKind::AstPass(kind) => kind.descr().into(),
503 ExpnKind::Desugaring(kind) => {
504 format!("this {} desugaring", kind.descr()).into()
512 if macro_backtrace.len() > 1 && always_backtrace {
513 // only specify order when the macro
514 // backtrace is multiple levels deep
515 format!(" (#{})", i + 1)
522 if !always_backtrace {
528 for (label_span, label_text) in new_labels {
529 span.push_span_label(label_span, label_text);
533 // This does a small "fix" for multispans by looking to see if it can find any that
534 // point directly at external macros. Since these are often difficult to read,
535 // this will change the span to point at the use site.
536 fn fix_multispans_in_extern_macros(
538 source_map: &Option<Lrc<SourceMap>>,
539 span: &mut MultiSpan,
540 children: &mut Vec<SubDiagnostic>,
542 let Some(source_map) = source_map else { return };
543 debug!("fix_multispans_in_extern_macros: before: span={:?} children={:?}", span, children);
544 self.fix_multispan_in_extern_macros(source_map, span);
545 for child in children.iter_mut() {
546 self.fix_multispan_in_extern_macros(source_map, &mut child.span);
548 debug!("fix_multispans_in_extern_macros: after: span={:?} children={:?}", span, children);
551 // This "fixes" MultiSpans that contain `Span`s pointing to locations inside of external macros.
552 // Since these locations are often difficult to read,
553 // we move these spans from the external macros to their corresponding use site.
554 fn fix_multispan_in_extern_macros(&self, source_map: &Lrc<SourceMap>, span: &mut MultiSpan) {
555 // First, find all the spans in external macros and point instead at their use site.
556 let replacements: Vec<(Span, Span)> = span
560 .chain(span.span_labels().iter().map(|sp_label| sp_label.span))
562 if !sp.is_dummy() && source_map.is_imported(sp) {
563 let maybe_callsite = sp.source_callsite();
564 if sp != maybe_callsite {
565 return Some((sp, maybe_callsite));
572 // After we have them, make sure we replace these 'bad' def sites with their use sites.
573 for (from, to) in replacements {
574 span.replace(from, to);
579 impl Emitter for EmitterWriter {
580 fn source_map(&self) -> Option<&Lrc<SourceMap>> {
584 fn fluent_bundle(&self) -> Option<&Lrc<FluentBundle>> {
585 self.fluent_bundle.as_ref()
588 fn fallback_fluent_bundle(&self) -> &FluentBundle {
589 &**self.fallback_bundle
592 fn emit_diagnostic(&mut self, diag: &Diagnostic) {
593 let fluent_args = self.to_fluent_args(diag.args());
595 let mut children = diag.children.clone();
596 let (mut primary_span, suggestions) = self.primary_span_formatted(&diag, &fluent_args);
597 debug!("emit_diagnostic: suggestions={:?}", suggestions);
599 self.fix_multispans_in_extern_macros_and_render_macro_backtrace(
604 self.macro_backtrace,
607 self.emit_messages_default(
618 fn should_show_explain(&self) -> bool {
622 fn supports_color(&self) -> bool {
623 self.dst.supports_color()
627 /// An emitter that does nothing when emitting a non-fatal diagnostic.
628 /// Fatal diagnostics are forwarded to `fatal_handler` to avoid silent
629 /// failures of rustc, as witnessed e.g. in issue #89358.
630 pub struct SilentEmitter {
631 pub fatal_handler: Handler,
632 pub fatal_note: Option<String>,
635 impl Emitter for SilentEmitter {
636 fn source_map(&self) -> Option<&Lrc<SourceMap>> {
640 fn fluent_bundle(&self) -> Option<&Lrc<FluentBundle>> {
644 fn fallback_fluent_bundle(&self) -> &FluentBundle {
645 panic!("silent emitter attempted to translate message")
648 fn emit_diagnostic(&mut self, d: &Diagnostic) {
649 if d.level == Level::Fatal {
650 let mut d = d.clone();
651 if let Some(ref note) = self.fatal_note {
654 self.fatal_handler.emit_diagnostic(&mut d);
659 /// Maximum number of lines we will print for a multiline suggestion; arbitrary.
661 /// This should be replaced with a more involved mechanism to output multiline suggestions that
662 /// more closely mimics the regular diagnostic output, where irrelevant code lines are elided.
663 pub const MAX_SUGGESTION_HIGHLIGHT_LINES: usize = 6;
664 /// Maximum number of suggestions to be shown
666 /// Arbitrary, but taken from trait import suggestion limit
667 pub const MAX_SUGGESTIONS: usize = 4;
669 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
670 pub enum ColorConfig {
677 fn to_color_choice(self) -> ColorChoice {
679 ColorConfig::Always => {
680 if atty::is(atty::Stream::Stderr) {
683 ColorChoice::AlwaysAnsi
686 ColorConfig::Never => ColorChoice::Never,
687 ColorConfig::Auto if atty::is(atty::Stream::Stderr) => ColorChoice::Auto,
688 ColorConfig::Auto => ColorChoice::Never,
691 fn suggests_using_colors(self) -> bool {
693 ColorConfig::Always | ColorConfig::Auto => true,
694 ColorConfig::Never => false,
699 /// Handles the writing of `HumanReadableErrorType::Default` and `HumanReadableErrorType::Short`
700 pub struct EmitterWriter {
702 sm: Option<Lrc<SourceMap>>,
703 fluent_bundle: Option<Lrc<FluentBundle>>,
704 fallback_bundle: LazyFallbackBundle,
708 terminal_width: Option<usize>,
710 macro_backtrace: bool,
714 pub struct FileWithAnnotatedLines {
715 pub file: Lrc<SourceFile>,
716 pub lines: Vec<Line>,
717 multiline_depth: usize,
722 color_config: ColorConfig,
723 source_map: Option<Lrc<SourceMap>>,
724 fluent_bundle: Option<Lrc<FluentBundle>>,
725 fallback_bundle: LazyFallbackBundle,
728 terminal_width: Option<usize>,
729 macro_backtrace: bool,
731 let dst = Destination::from_stderr(color_config);
746 dst: Box<dyn Write + Send>,
747 source_map: Option<Lrc<SourceMap>>,
748 fluent_bundle: Option<Lrc<FluentBundle>>,
749 fallback_bundle: LazyFallbackBundle,
753 terminal_width: Option<usize>,
754 macro_backtrace: bool,
757 dst: Raw(dst, colored),
769 pub fn ui_testing(mut self, ui_testing: bool) -> Self {
770 self.ui_testing = ui_testing;
774 fn maybe_anonymized(&self, line_num: usize) -> String {
775 if self.ui_testing { ANONYMIZED_LINE_NUM.to_string() } else { line_num.to_string() }
780 buffer: &mut StyledBuffer,
788 // Tabs are assumed to have been replaced by spaces in calling code.
789 debug_assert!(!source_string.contains('\t'));
790 let line_len = source_string.len();
791 // Create the source line we will highlight.
792 let left = margin.left(line_len);
793 let right = margin.right(line_len);
794 // On long lines, we strip the source line, accounting for unicode.
796 let code: String = source_string
800 // Make sure that the trimming on the right will fall within the terminal width.
801 // FIXME: `unicode_width` sometimes disagrees with terminals on how wide a `char` is.
802 // For now, just accept that sometimes the code line will be longer than desired.
803 let next = unicode_width::UnicodeWidthChar::width(*ch).unwrap_or(1);
804 if taken + next > right - left {
811 buffer.puts(line_offset, code_offset, &code, Style::Quotation);
812 if margin.was_cut_left() {
813 // We have stripped some code/whitespace from the beginning, make it clear.
814 buffer.puts(line_offset, code_offset, "...", Style::LineNumber);
816 if margin.was_cut_right(line_len) {
817 // We have stripped some code after the right-most span end, make it clear we did so.
818 buffer.puts(line_offset, code_offset + taken - 3, "...", Style::LineNumber);
820 buffer.puts(line_offset, 0, &self.maybe_anonymized(line_index), Style::LineNumber);
822 draw_col_separator(buffer, line_offset, width_offset - 2);
825 fn render_source_line(
827 buffer: &mut StyledBuffer,
828 file: Lrc<SourceFile>,
833 ) -> Vec<(usize, Style)> {
839 // | secondary span label
841 // ^^ ^ ^^^ ^^^^ ^^^ we don't care about code too far to the right of a span, we trim it
843 // | | | actual code found in your source code and the spans we use to mark it
844 // | | when there's too much wasted space to the left, trim it
845 // | vertical divider between the column number and the code
848 if line.line_index == 0 {
852 let source_string = match file.get_line(line.line_index - 1) {
853 Some(s) => normalize_whitespace(&*s),
854 None => return Vec::new(),
857 let line_offset = buffer.num_lines();
860 let left = margin.left(source_string.len());
862 // Account for unicode characters of width !=0 that were removed.
863 let left = source_string
866 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
879 // Special case when there's only one annotation involved, it is the start of a multiline
880 // span and there's no text at the beginning of the code line. Instead of doing the whole
889 // we simplify the output to:
895 if let [ann] = &line.annotations[..] {
896 if let AnnotationType::MultilineStart(depth) = ann.annotation_type {
897 if source_string.chars().take(ann.start_col).all(|c| c.is_whitespace()) {
898 let style = if ann.is_primary {
899 Style::UnderlinePrimary
901 Style::UnderlineSecondary
903 buffer.putc(line_offset, width_offset + depth - 1, '/', style);
904 return vec![(depth, style)];
909 // We want to display like this:
911 // vec.push(vec.pop().unwrap());
912 // --- ^^^ - previous borrow ends here
914 // | error occurs here
915 // previous borrow of `vec` occurs here
917 // But there are some weird edge cases to be aware of:
919 // vec.push(vec.pop().unwrap());
920 // -------- - previous borrow ends here
922 // |this makes no sense
923 // previous borrow of `vec` occurs here
925 // For this reason, we group the lines into "highlight lines"
926 // and "annotations lines", where the highlight lines have the `^`.
928 // Sort the annotations by (start, end col)
929 // The labels are reversed, sort and then reversed again.
930 // Consider a list of annotations (A1, A2, C1, C2, B1, B2) where
931 // the letter signifies the span. Here we are only sorting by the
932 // span and hence, the order of the elements with the same span will
933 // not change. On reversing the ordering (|a, b| but b.cmp(a)), you get
934 // (C1, C2, B1, B2, A1, A2). All the elements with the same span are
935 // still ordered first to last, but all the elements with different
936 // spans are ordered by their spans in last to first order. Last to
937 // first order is important, because the jiggly lines and | are on
938 // the left, so the rightmost span needs to be rendered first,
939 // otherwise the lines would end up needing to go over a message.
941 let mut annotations = line.annotations.clone();
942 annotations.sort_by_key(|a| Reverse(a.start_col));
944 // First, figure out where each label will be positioned.
946 // In the case where you have the following annotations:
948 // vec.push(vec.pop().unwrap());
949 // -------- - previous borrow ends here [C]
951 // |this makes no sense [B]
952 // previous borrow of `vec` occurs here [A]
954 // `annotations_position` will hold [(2, A), (1, B), (0, C)].
956 // We try, when possible, to stick the rightmost annotation at the end
957 // of the highlight line:
959 // vec.push(vec.pop().unwrap());
960 // --- --- - previous borrow ends here
962 // But sometimes that's not possible because one of the other
963 // annotations overlaps it. For example, from the test
964 // `span_overlap_label`, we have the following annotations
965 // (written on distinct lines for clarity):
971 // In this case, we can't stick the rightmost-most label on
972 // the highlight line, or we would get:
979 // which is totally weird. Instead we want:
987 // which is...less weird, at least. In fact, in general, if
988 // the rightmost span overlaps with any other span, we should
989 // use the "hang below" version, so we can at least make it
990 // clear where the span *starts*. There's an exception for this
991 // logic, when the labels do not have a message:
1006 let mut annotations_position = vec![];
1007 let mut line_len = 0;
1009 for (i, annotation) in annotations.iter().enumerate() {
1010 for (j, next) in annotations.iter().enumerate() {
1011 if overlaps(next, annotation, 0) // This label overlaps with another one and both
1012 && annotation.has_label() // take space (they have text and are not
1013 && j > i // multiline lines).
1015 // We're currently on the first line, move the label one line down
1017 // If we're overlapping with an un-labelled annotation with the same span
1018 // we can just merge them in the output
1019 if next.start_col == annotation.start_col
1020 && next.end_col == annotation.end_col
1021 && !next.has_label()
1026 // This annotation needs a new line in the output.
1031 annotations_position.push((p, annotation));
1032 for (j, next) in annotations.iter().enumerate() {
1034 let l = next.label.as_ref().map_or(0, |label| label.len() + 2);
1035 if (overlaps(next, annotation, l) // Do not allow two labels to be in the same
1036 // line if they overlap including padding, to
1037 // avoid situations like:
1044 && annotation.has_label() // Both labels must have some text, otherwise
1045 && next.has_label()) // they are not overlapping.
1046 // Do not add a new line if this annotation
1047 // or the next are vertical line placeholders.
1048 || (annotation.takes_space() // If either this or the next annotation is
1049 && next.has_label()) // multiline start/end, move it to a new line
1050 || (annotation.has_label() // so as not to overlap the horizontal lines.
1051 && next.takes_space())
1052 || (annotation.takes_space() && next.takes_space())
1053 || (overlaps(next, annotation, l)
1054 && next.end_col <= annotation.end_col
1059 // This annotation needs a new line in the output.
1065 line_len = max(line_len, p);
1072 // If there are no annotations or the only annotations on this line are
1073 // MultilineLine, then there's only code being shown, stop processing.
1074 if line.annotations.iter().all(|a| a.is_line()) {
1078 // Write the column separator.
1080 // After this we will have:
1089 for pos in 0..=line_len {
1090 draw_col_separator(buffer, line_offset + pos + 1, width_offset - 2);
1093 // Write the horizontal lines for multiline annotations
1094 // (only the first and last lines need this).
1096 // After this we will have:
1105 for &(pos, annotation) in &annotations_position {
1106 let style = if annotation.is_primary {
1107 Style::UnderlinePrimary
1109 Style::UnderlineSecondary
1112 match annotation.annotation_type {
1113 AnnotationType::MultilineStart(depth) | AnnotationType::MultilineEnd(depth) => {
1118 width_offset + depth,
1119 (code_offset + annotation.start_col).saturating_sub(left),
1123 _ if self.teach => {
1124 buffer.set_style_range(
1126 (code_offset + annotation.start_col).saturating_sub(left),
1127 (code_offset + annotation.end_col).saturating_sub(left),
1129 annotation.is_primary,
1136 // Write the vertical lines for labels that are on a different line as the underline.
1138 // After this we will have:
1147 for &(pos, annotation) in &annotations_position {
1148 let style = if annotation.is_primary {
1149 Style::UnderlinePrimary
1151 Style::UnderlineSecondary
1155 if pos > 1 && (annotation.has_label() || annotation.takes_space()) {
1156 for p in line_offset + 1..=line_offset + pos {
1159 (code_offset + annotation.start_col).saturating_sub(left),
1165 match annotation.annotation_type {
1166 AnnotationType::MultilineStart(depth) => {
1167 for p in line_offset + pos + 1..line_offset + line_len + 2 {
1168 buffer.putc(p, width_offset + depth - 1, '|', style);
1171 AnnotationType::MultilineEnd(depth) => {
1172 for p in line_offset..=line_offset + pos {
1173 buffer.putc(p, width_offset + depth - 1, '|', style);
1180 // Write the labels on the annotations that actually have a label.
1182 // After this we will have:
1187 // | something about `foo`
1191 for &(pos, annotation) in &annotations_position {
1193 if annotation.is_primary { Style::LabelPrimary } else { Style::LabelSecondary };
1194 let (pos, col) = if pos == 0 {
1195 (pos + 1, (annotation.end_col + 1).saturating_sub(left))
1197 (pos + 2, annotation.start_col.saturating_sub(left))
1199 if let Some(ref label) = annotation.label {
1200 buffer.puts(line_offset + pos, code_offset + col, &label, style);
1204 // Sort from biggest span to smallest span so that smaller spans are
1205 // represented in the output:
1210 // | | something about `foo`
1211 // | something about `fn foo()`
1212 annotations_position.sort_by_key(|(_, ann)| {
1213 // Decreasing order. When annotations share the same length, prefer `Primary`.
1214 (Reverse(ann.len()), ann.is_primary)
1217 // Write the underlines.
1219 // After this we will have:
1224 // | something about `foo`
1228 for &(_, annotation) in &annotations_position {
1229 let (underline, style) = if annotation.is_primary {
1230 ('^', Style::UnderlinePrimary)
1232 ('-', Style::UnderlineSecondary)
1234 for p in annotation.start_col..annotation.end_col {
1237 (code_offset + p).saturating_sub(left),
1243 annotations_position
1245 .filter_map(|&(_, annotation)| match annotation.annotation_type {
1246 AnnotationType::MultilineStart(p) | AnnotationType::MultilineEnd(p) => {
1247 let style = if annotation.is_primary {
1250 Style::LabelSecondary
1256 .collect::<Vec<_>>()
1259 fn get_multispan_max_line_num(&mut self, msp: &MultiSpan) -> usize {
1260 let Some(ref sm) = self.sm else {
1264 let will_be_emitted = |span: Span| {
1265 !span.is_dummy() && {
1266 let file = sm.lookup_source_file(span.hi());
1267 sm.ensure_source_file_source_present(file)
1272 for primary_span in msp.primary_spans() {
1273 if will_be_emitted(*primary_span) {
1274 let hi = sm.lookup_char_pos(primary_span.hi());
1275 max = (hi.line).max(max);
1278 if !self.short_message {
1279 for span_label in msp.span_labels() {
1280 if will_be_emitted(span_label.span) {
1281 let hi = sm.lookup_char_pos(span_label.span.hi());
1282 max = (hi.line).max(max);
1290 fn get_max_line_num(&mut self, span: &MultiSpan, children: &[SubDiagnostic]) -> usize {
1291 let primary = self.get_multispan_max_line_num(span);
1294 .map(|sub| self.get_multispan_max_line_num(&sub.span))
1300 /// Adds a left margin to every line but the first, given a padding length and the label being
1301 /// displayed, keeping the provided highlighting.
1304 buffer: &mut StyledBuffer,
1305 msg: &[(DiagnosticMessage, Style)],
1306 args: &FluentArgs<'_>,
1309 override_style: Option<Style>,
1311 // The extra 5 ` ` is padding that's always needed to align to the `note: `:
1314 // --> file.rs:13:20
1319 // = note: multiline
1324 // | | length of label
1326 // `max_line_num_len`
1327 let padding = " ".repeat(padding + label.len() + 5);
1329 /// Returns `override` if it is present and `style` is `NoStyle` or `style` otherwise
1330 fn style_or_override(style: Style, override_: Option<Style>) -> Style {
1331 match (style, override_) {
1332 (Style::NoStyle, Some(override_)) => override_,
1337 let mut line_number = 0;
1339 // Provided the following diagnostic message:
1343 // ("highlighted multiline\nstring to\nsee how it ", Style::NoStyle),
1344 // ("looks", Style::Highlight),
1345 // ("with\nvery ", Style::NoStyle),
1346 // ("weird", Style::Highlight),
1347 // (" formats\n", Style::NoStyle),
1348 // ("see?", Style::Highlight),
1351 // the expected output on a note is (* surround the highlighted text)
1353 // = note: highlighted multiline
1355 // see how it *looks* with
1356 // very *weird* formats
1358 for &(ref text, ref style) in msg.iter() {
1359 let text = self.translate_message(text, args);
1360 let lines = text.split('\n').collect::<Vec<_>>();
1361 if lines.len() > 1 {
1362 for (i, line) in lines.iter().enumerate() {
1365 buffer.append(line_number, &padding, Style::NoStyle);
1367 buffer.append(line_number, line, style_or_override(*style, override_style));
1370 buffer.append(line_number, &text, style_or_override(*style, override_style));
1375 fn emit_message_default(
1378 msg: &[(DiagnosticMessage, Style)],
1379 args: &FluentArgs<'_>,
1380 code: &Option<DiagnosticId>,
1382 max_line_num_len: usize,
1384 ) -> io::Result<()> {
1385 let mut buffer = StyledBuffer::new();
1387 if !msp.has_primary_spans() && !msp.has_span_labels() && is_secondary && !self.short_message
1389 // This is a secondary message with no span info
1390 for _ in 0..max_line_num_len {
1391 buffer.prepend(0, " ", Style::NoStyle);
1393 draw_note_separator(&mut buffer, 0, max_line_num_len + 1);
1394 if *level != Level::FailureNote {
1395 buffer.append(0, level.to_str(), Style::MainHeaderMsg);
1396 buffer.append(0, ": ", Style::NoStyle);
1398 self.msg_to_buffer(&mut buffer, msg, args, max_line_num_len, "note", None);
1400 let mut label_width = 0;
1401 // The failure note level itself does not provide any useful diagnostic information
1402 if *level != Level::FailureNote {
1403 buffer.append(0, level.to_str(), Style::Level(*level));
1404 label_width += level.to_str().len();
1406 // only render error codes, not lint codes
1407 if let Some(DiagnosticId::Error(ref code)) = *code {
1408 buffer.append(0, "[", Style::Level(*level));
1409 buffer.append(0, &code, Style::Level(*level));
1410 buffer.append(0, "]", Style::Level(*level));
1411 label_width += 2 + code.len();
1413 let header_style = if is_secondary { Style::HeaderMsg } else { Style::MainHeaderMsg };
1414 if *level != Level::FailureNote {
1415 buffer.append(0, ": ", header_style);
1418 for &(ref text, _) in msg.iter() {
1419 let text = self.translate_message(text, args);
1420 // Account for newlines to align output to its label.
1421 for (line, text) in normalize_whitespace(&text).lines().enumerate() {
1426 if line == 0 { String::new() } else { " ".repeat(label_width) },
1435 let mut annotated_files = FileWithAnnotatedLines::collect_annotations(self, args, msp);
1437 // Make sure our primary file comes first
1438 let (primary_lo, sm) = if let (Some(sm), Some(ref primary_span)) =
1439 (self.sm.as_ref(), msp.primary_span().as_ref())
1441 if !primary_span.is_dummy() {
1442 (sm.lookup_char_pos(primary_span.lo()), sm)
1444 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1448 // If we don't have span information, emit and exit
1449 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1453 annotated_files.binary_search_by(|x| x.file.name.cmp(&primary_lo.file.name))
1455 annotated_files.swap(0, pos);
1458 // Print out the annotate source lines that correspond with the error
1459 for annotated_file in annotated_files {
1460 // we can't annotate anything if the source is unavailable.
1461 if !sm.ensure_source_file_source_present(annotated_file.file.clone()) {
1465 // print out the span location and spacer before we print the annotated source
1466 // to do this, we need to know if this span will be primary
1467 let is_primary = primary_lo.file.name == annotated_file.file.name;
1469 let loc = primary_lo.clone();
1470 if !self.short_message {
1471 // remember where we are in the output buffer for easy reference
1472 let buffer_msg_line_offset = buffer.num_lines();
1474 buffer.prepend(buffer_msg_line_offset, "--> ", Style::LineNumber);
1476 buffer_msg_line_offset,
1479 sm.filename_for_diagnostics(&loc.file.name),
1480 sm.doctest_offset_line(&loc.file.name, loc.line),
1483 Style::LineAndColumn,
1485 for _ in 0..max_line_num_len {
1486 buffer.prepend(buffer_msg_line_offset, " ", Style::NoStyle);
1493 sm.filename_for_diagnostics(&loc.file.name),
1494 sm.doctest_offset_line(&loc.file.name, loc.line),
1497 Style::LineAndColumn,
1500 } else if !self.short_message {
1501 // remember where we are in the output buffer for easy reference
1502 let buffer_msg_line_offset = buffer.num_lines();
1505 draw_col_separator_no_space(
1507 buffer_msg_line_offset,
1508 max_line_num_len + 1,
1511 // Then, the secondary file indicator
1512 buffer.prepend(buffer_msg_line_offset + 1, "::: ", Style::LineNumber);
1513 let loc = if let Some(first_line) = annotated_file.lines.first() {
1514 let col = if let Some(first_annotation) = first_line.annotations.first() {
1515 format!(":{}", first_annotation.start_col + 1)
1521 sm.filename_for_diagnostics(&annotated_file.file.name),
1522 sm.doctest_offset_line(&annotated_file.file.name, first_line.line_index),
1526 format!("{}", sm.filename_for_diagnostics(&annotated_file.file.name))
1528 buffer.append(buffer_msg_line_offset + 1, &loc, Style::LineAndColumn);
1529 for _ in 0..max_line_num_len {
1530 buffer.prepend(buffer_msg_line_offset + 1, " ", Style::NoStyle);
1534 if !self.short_message {
1535 // Put in the spacer between the location and annotated source
1536 let buffer_msg_line_offset = buffer.num_lines();
1537 draw_col_separator_no_space(
1539 buffer_msg_line_offset,
1540 max_line_num_len + 1,
1543 // Contains the vertical lines' positions for active multiline annotations
1544 let mut multilines = FxHashMap::default();
1546 // Get the left-side margin to remove it
1547 let mut whitespace_margin = usize::MAX;
1548 for line_idx in 0..annotated_file.lines.len() {
1549 let file = annotated_file.file.clone();
1550 let line = &annotated_file.lines[line_idx];
1551 if let Some(source_string) = file.get_line(line.line_index - 1) {
1552 let leading_whitespace = source_string
1554 .take_while(|c| c.is_whitespace())
1557 // Tabs are displayed as 4 spaces
1563 if source_string.chars().any(|c| !c.is_whitespace()) {
1564 whitespace_margin = min(whitespace_margin, leading_whitespace);
1568 if whitespace_margin == usize::MAX {
1569 whitespace_margin = 0;
1572 // Left-most column any visible span points at.
1573 let mut span_left_margin = usize::MAX;
1574 for line in &annotated_file.lines {
1575 for ann in &line.annotations {
1576 span_left_margin = min(span_left_margin, ann.start_col);
1577 span_left_margin = min(span_left_margin, ann.end_col);
1580 if span_left_margin == usize::MAX {
1581 span_left_margin = 0;
1584 // Right-most column any visible span points at.
1585 let mut span_right_margin = 0;
1586 let mut label_right_margin = 0;
1587 let mut max_line_len = 0;
1588 for line in &annotated_file.lines {
1591 annotated_file.file.get_line(line.line_index - 1).map_or(0, |s| s.len()),
1593 for ann in &line.annotations {
1594 span_right_margin = max(span_right_margin, ann.start_col);
1595 span_right_margin = max(span_right_margin, ann.end_col);
1596 // FIXME: account for labels not in the same line
1597 let label_right = ann.label.as_ref().map_or(0, |l| l.len() + 1);
1598 label_right_margin = max(label_right_margin, ann.end_col + label_right);
1602 let width_offset = 3 + max_line_num_len;
1603 let code_offset = if annotated_file.multiline_depth == 0 {
1606 width_offset + annotated_file.multiline_depth + 1
1609 let column_width = if let Some(width) = self.terminal_width {
1610 width.saturating_sub(code_offset)
1611 } else if self.ui_testing {
1612 DEFAULT_COLUMN_WIDTH
1614 termize::dimensions()
1615 .map(|(w, _)| w.saturating_sub(code_offset))
1616 .unwrap_or(DEFAULT_COLUMN_WIDTH)
1619 let margin = Margin::new(
1628 // Next, output the annotate source for this file
1629 for line_idx in 0..annotated_file.lines.len() {
1630 let previous_buffer_line = buffer.num_lines();
1632 let depths = self.render_source_line(
1634 annotated_file.file.clone(),
1635 &annotated_file.lines[line_idx],
1641 let mut to_add = FxHashMap::default();
1643 for (depth, style) in depths {
1644 if multilines.remove(&depth).is_none() {
1645 to_add.insert(depth, style);
1649 // Set the multiline annotation vertical lines to the left of
1650 // the code in this line.
1651 for (depth, style) in &multilines {
1652 for line in previous_buffer_line..buffer.num_lines() {
1653 draw_multiline_line(&mut buffer, line, width_offset, *depth, *style);
1656 // check to see if we need to print out or elide lines that come between
1657 // this annotated line and the next one.
1658 if line_idx < (annotated_file.lines.len() - 1) {
1659 let line_idx_delta = annotated_file.lines[line_idx + 1].line_index
1660 - annotated_file.lines[line_idx].line_index;
1661 if line_idx_delta > 2 {
1662 let last_buffer_line_num = buffer.num_lines();
1663 buffer.puts(last_buffer_line_num, 0, "...", Style::LineNumber);
1665 // Set the multiline annotation vertical lines on `...` bridging line.
1666 for (depth, style) in &multilines {
1667 draw_multiline_line(
1669 last_buffer_line_num,
1675 } else if line_idx_delta == 2 {
1676 let unannotated_line = annotated_file
1678 .get_line(annotated_file.lines[line_idx].line_index)
1679 .unwrap_or_else(|| Cow::from(""));
1681 let last_buffer_line_num = buffer.num_lines();
1685 &normalize_whitespace(&unannotated_line),
1686 annotated_file.lines[line_idx + 1].line_index - 1,
1687 last_buffer_line_num,
1693 for (depth, style) in &multilines {
1694 draw_multiline_line(
1696 last_buffer_line_num,
1705 multilines.extend(&to_add);
1710 // final step: take our styled buffer, render it, then output it
1711 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1716 fn emit_suggestion_default(
1718 suggestion: &CodeSuggestion,
1719 args: &FluentArgs<'_>,
1721 max_line_num_len: usize,
1722 ) -> io::Result<()> {
1723 let Some(ref sm) = self.sm else {
1727 // Render the replacements for each suggestion
1728 let suggestions = suggestion.splice_lines(&**sm);
1729 debug!("emit_suggestion_default: suggestions={:?}", suggestions);
1731 if suggestions.is_empty() {
1732 // Suggestions coming from macros can have malformed spans. This is a heavy handed
1733 // approach to avoid ICEs by ignoring the suggestion outright.
1737 let mut buffer = StyledBuffer::new();
1739 // Render the suggestion message
1740 buffer.append(0, level.to_str(), Style::Level(*level));
1741 buffer.append(0, ": ", Style::HeaderMsg);
1745 &[(suggestion.msg.to_owned(), Style::NoStyle)],
1749 Some(Style::HeaderMsg),
1752 let mut row_num = 2;
1753 draw_col_separator_no_space(&mut buffer, 1, max_line_num_len + 1);
1754 let mut notice_capitalization = false;
1755 for (complete, parts, highlights, only_capitalization) in
1756 suggestions.iter().take(MAX_SUGGESTIONS)
1758 notice_capitalization |= only_capitalization;
1760 let has_deletion = parts.iter().any(|p| p.is_deletion());
1761 let is_multiline = complete.lines().count() > 1;
1763 enum DisplaySuggestion {
1769 let show_code_change = if has_deletion && !is_multiline {
1770 DisplaySuggestion::Diff
1771 } else if (parts.len() != 1 || parts[0].snippet.trim() != complete.trim())
1774 DisplaySuggestion::Underline
1776 DisplaySuggestion::None
1779 if let DisplaySuggestion::Diff = show_code_change {
1784 .span_to_lines(parts[0].span)
1785 .expect("span_to_lines failed when emitting suggestion");
1787 assert!(!file_lines.lines.is_empty() || parts[0].span.is_dummy());
1789 let line_start = sm.lookup_char_pos(parts[0].span.lo()).line;
1790 draw_col_separator_no_space(&mut buffer, 1, max_line_num_len + 1);
1791 let mut lines = complete.lines();
1792 if lines.clone().next().is_none() {
1793 // Account for a suggestion to completely remove a line(s) with whitespace (#94192).
1794 let line_end = sm.lookup_char_pos(parts[0].span.hi()).line;
1795 for line in line_start..=line_end {
1797 row_num - 1 + line - line_start,
1799 &self.maybe_anonymized(line),
1803 row_num - 1 + line - line_start,
1804 max_line_num_len + 1,
1809 row_num - 1 + line - line_start,
1810 max_line_num_len + 3,
1811 &normalize_whitespace(&*file_lines.file.get_line(line - 1).unwrap()),
1815 row_num += line_end - line_start;
1817 for (line_pos, (line, highlight_parts)) in
1818 lines.by_ref().zip(highlights).take(MAX_SUGGESTION_HIGHLIGHT_LINES).enumerate()
1820 // Print the span column to avoid confusion
1824 &self.maybe_anonymized(line_start + line_pos),
1827 if let DisplaySuggestion::Diff = show_code_change {
1828 // Add the line number for both addition and removal to drive the point home.
1830 // N - fn foo<A: T>(bar: A) {
1831 // N + fn foo(bar: impl T) {
1835 &self.maybe_anonymized(line_start + line_pos),
1838 buffer.puts(row_num - 1, max_line_num_len + 1, "- ", Style::Removal);
1841 max_line_num_len + 3,
1842 &normalize_whitespace(
1845 .get_line(file_lines.lines[line_pos].line_index)
1850 buffer.puts(row_num, max_line_num_len + 1, "+ ", Style::Addition);
1851 } else if is_multiline {
1852 match &highlight_parts[..] {
1853 [SubstitutionHighlight { start: 0, end }] if *end == line.len() => {
1854 buffer.puts(row_num, max_line_num_len + 1, "+ ", Style::Addition);
1857 draw_col_separator(&mut buffer, row_num, max_line_num_len + 1);
1860 buffer.puts(row_num, max_line_num_len + 1, "~ ", Style::Addition);
1864 draw_col_separator(&mut buffer, row_num, max_line_num_len + 1);
1867 // print the suggestion
1868 buffer.append(row_num, &normalize_whitespace(line), Style::NoStyle);
1870 // Colorize addition/replacements with green.
1871 for &SubstitutionHighlight { start, end } in highlight_parts {
1872 // Account for tabs when highlighting (#87972).
1873 let tabs: usize = line
1876 .map(|ch| match ch {
1881 buffer.set_style_range(
1883 max_line_num_len + 3 + start + tabs,
1884 max_line_num_len + 3 + end + tabs,
1892 // This offset and the ones below need to be signed to account for replacement code
1893 // that is shorter than the original code.
1894 let mut offsets: Vec<(usize, isize)> = Vec::new();
1895 // Only show an underline in the suggestions if the suggestion is not the
1896 // entirety of the code being shown and the displayed code is not multiline.
1897 if let DisplaySuggestion::Diff | DisplaySuggestion::Underline = show_code_change {
1898 draw_col_separator(&mut buffer, row_num, max_line_num_len + 1);
1900 let span_start_pos = sm.lookup_char_pos(part.span.lo()).col_display;
1901 let span_end_pos = sm.lookup_char_pos(part.span.hi()).col_display;
1903 // Do not underline the leading...
1904 let start = part.snippet.len().saturating_sub(part.snippet.trim_start().len());
1905 // ...or trailing spaces. Account for substitutions containing unicode
1907 let sub_len: usize = part
1911 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
1914 let offset: isize = offsets
1917 |(start, v)| if span_start_pos <= *start { None } else { Some(v) },
1920 let underline_start = (span_start_pos + start) as isize + offset;
1921 let underline_end = (span_start_pos + start + sub_len) as isize + offset;
1922 assert!(underline_start >= 0 && underline_end >= 0);
1923 let padding: usize = max_line_num_len + 3;
1924 for p in underline_start..underline_end {
1925 if let DisplaySuggestion::Underline = show_code_change {
1926 // If this is a replacement, underline with `^`, if this is an addition
1927 // underline with `+`.
1930 (padding as isize + p) as usize,
1931 if part.is_addition(&sm) { '+' } else { '~' },
1936 if let DisplaySuggestion::Diff = show_code_change {
1937 // Colorize removal with red in diff format.
1938 buffer.set_style_range(
1940 (padding as isize + span_start_pos as isize) as usize,
1941 (padding as isize + span_end_pos as isize) as usize,
1947 // length of the code after substitution
1948 let full_sub_len = part
1951 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
1952 .sum::<usize>() as isize;
1954 // length of the code to be substituted
1955 let snippet_len = span_end_pos as isize - span_start_pos as isize;
1956 // For multiple substitutions, use the position *after* the previous
1957 // substitutions have happened, only when further substitutions are
1958 // located strictly after.
1959 offsets.push((span_end_pos, full_sub_len - snippet_len));
1964 // if we elided some lines, add an ellipsis
1965 if lines.next().is_some() {
1966 buffer.puts(row_num, max_line_num_len - 1, "...", Style::LineNumber);
1967 } else if let DisplaySuggestion::None = show_code_change {
1968 draw_col_separator_no_space(&mut buffer, row_num, max_line_num_len + 1);
1972 if suggestions.len() > MAX_SUGGESTIONS {
1973 let others = suggestions.len() - MAX_SUGGESTIONS;
1974 let msg = format!("and {} other candidate{}", others, pluralize!(others));
1975 buffer.puts(row_num, max_line_num_len + 3, &msg, Style::NoStyle);
1976 } else if notice_capitalization {
1977 let msg = "notice the capitalization difference";
1978 buffer.puts(row_num, max_line_num_len + 3, &msg, Style::NoStyle);
1980 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1984 fn emit_messages_default(
1987 message: &[(DiagnosticMessage, Style)],
1988 args: &FluentArgs<'_>,
1989 code: &Option<DiagnosticId>,
1991 children: &[SubDiagnostic],
1992 suggestions: &[CodeSuggestion],
1994 let max_line_num_len = if self.ui_testing {
1995 ANONYMIZED_LINE_NUM.len()
1997 let n = self.get_max_line_num(span, children);
1998 num_decimal_digits(n)
2001 match self.emit_message_default(span, message, args, code, level, max_line_num_len, false) {
2003 if !children.is_empty()
2004 || suggestions.iter().any(|s| s.style != SuggestionStyle::CompletelyHidden)
2006 let mut buffer = StyledBuffer::new();
2007 if !self.short_message {
2008 draw_col_separator_no_space(&mut buffer, 0, max_line_num_len + 1);
2010 if let Err(e) = emit_to_destination(
2016 panic!("failed to emit error: {}", e)
2019 if !self.short_message {
2020 for child in children {
2021 let span = child.render_span.as_ref().unwrap_or(&child.span);
2022 if let Err(err) = self.emit_message_default(
2031 panic!("failed to emit error: {}", err);
2034 for sugg in suggestions {
2035 if sugg.style == SuggestionStyle::CompletelyHidden {
2036 // do not display this suggestion, it is meant only for tools
2037 } else if sugg.style == SuggestionStyle::HideCodeAlways {
2038 if let Err(e) = self.emit_message_default(
2040 &[(sugg.msg.to_owned(), Style::HeaderMsg)],
2047 panic!("failed to emit error: {}", e);
2049 } else if let Err(e) =
2050 self.emit_suggestion_default(sugg, args, &Level::Help, max_line_num_len)
2052 panic!("failed to emit error: {}", e);
2057 Err(e) => panic!("failed to emit error: {}", e),
2060 let mut dst = self.dst.writable();
2061 match writeln!(dst) {
2062 Err(e) => panic!("failed to emit error: {}", e),
2064 if let Err(e) = dst.flush() {
2065 panic!("failed to emit error: {}", e)
2072 impl FileWithAnnotatedLines {
2073 /// Preprocess all the annotations so that they are grouped by file and by line number
2074 /// This helps us quickly iterate over the whole message (including secondary file spans)
2075 pub fn collect_annotations(
2076 emitter: &dyn Emitter,
2077 args: &FluentArgs<'_>,
2079 ) -> Vec<FileWithAnnotatedLines> {
2080 fn add_annotation_to_file(
2081 file_vec: &mut Vec<FileWithAnnotatedLines>,
2082 file: Lrc<SourceFile>,
2086 for slot in file_vec.iter_mut() {
2087 // Look through each of our files for the one we're adding to
2088 if slot.file.name == file.name {
2089 // See if we already have a line for it
2090 for line_slot in &mut slot.lines {
2091 if line_slot.line_index == line_index {
2092 line_slot.annotations.push(ann);
2096 // We don't have a line yet, create one
2097 slot.lines.push(Line { line_index, annotations: vec![ann] });
2102 // This is the first time we're seeing the file
2103 file_vec.push(FileWithAnnotatedLines {
2105 lines: vec![Line { line_index, annotations: vec![ann] }],
2110 let mut output = vec![];
2111 let mut multiline_annotations = vec![];
2113 if let Some(ref sm) = emitter.source_map() {
2114 for span_label in msp.span_labels() {
2115 if span_label.span.is_dummy() {
2119 let lo = sm.lookup_char_pos(span_label.span.lo());
2120 let mut hi = sm.lookup_char_pos(span_label.span.hi());
2122 // Watch out for "empty spans". If we get a span like 6..6, we
2123 // want to just display a `^` at 6, so convert that to
2124 // 6..7. This is degenerate input, but it's best to degrade
2125 // gracefully -- and the parser likes to supply a span like
2126 // that for EOF, in particular.
2128 if lo.col_display == hi.col_display && lo.line == hi.line {
2129 hi.col_display += 1;
2132 if lo.line != hi.line {
2133 let ml = MultilineAnnotation {
2135 line_start: lo.line,
2137 start_col: lo.col_display,
2138 end_col: hi.col_display,
2139 is_primary: span_label.is_primary,
2143 .map(|m| emitter.translate_message(m, args).to_string()),
2144 overlaps_exactly: false,
2146 multiline_annotations.push((lo.file, ml));
2148 let ann = Annotation {
2149 start_col: lo.col_display,
2150 end_col: hi.col_display,
2151 is_primary: span_label.is_primary,
2155 .map(|m| emitter.translate_message(m, args).to_string()),
2156 annotation_type: AnnotationType::Singleline,
2158 add_annotation_to_file(&mut output, lo.file, lo.line, ann);
2163 // Find overlapping multiline annotations, put them at different depths
2164 multiline_annotations.sort_by_key(|&(_, ref ml)| (ml.line_start, ml.line_end));
2165 for (_, ann) in multiline_annotations.clone() {
2166 for (_, a) in multiline_annotations.iter_mut() {
2167 // Move all other multiline annotations overlapping with this one
2168 // one level to the right.
2169 if !(ann.same_span(a))
2170 && num_overlap(ann.line_start, ann.line_end, a.line_start, a.line_end, true)
2173 } else if ann.same_span(a) && &ann != a {
2174 a.overlaps_exactly = true;
2181 let mut max_depth = 0; // max overlapping multiline spans
2182 for (file, ann) in multiline_annotations {
2183 max_depth = max(max_depth, ann.depth);
2184 let mut end_ann = ann.as_end();
2185 if !ann.overlaps_exactly {
2186 // avoid output like
2208 add_annotation_to_file(&mut output, file.clone(), ann.line_start, ann.as_start());
2209 // 4 is the minimum vertical length of a multiline span when presented: two lines
2210 // of code and two lines of underline. This is not true for the special case where
2211 // the beginning doesn't have an underline, but the current logic seems to be
2212 // working correctly.
2213 let middle = min(ann.line_start + 4, ann.line_end);
2214 for line in ann.line_start + 1..middle {
2215 // Every `|` that joins the beginning of the span (`___^`) to the end (`|__^`).
2216 add_annotation_to_file(&mut output, file.clone(), line, ann.as_line());
2218 let line_end = ann.line_end - 1;
2219 if middle < line_end {
2220 add_annotation_to_file(&mut output, file.clone(), line_end, ann.as_line());
2223 end_ann.annotation_type = AnnotationType::Singleline;
2225 add_annotation_to_file(&mut output, file, ann.line_end, end_ann);
2227 for file_vec in output.iter_mut() {
2228 file_vec.multiline_depth = max_depth;
2234 // instead of taking the String length or dividing by 10 while > 0, we multiply a limit by 10 until
2235 // we're higher. If the loop isn't exited by the `return`, the last multiplication will wrap, which
2236 // is OK, because while we cannot fit a higher power of 10 in a usize, the loop will end anyway.
2237 // This is also why we need the max number of decimal digits within a `usize`.
2238 fn num_decimal_digits(num: usize) -> usize {
2239 #[cfg(target_pointer_width = "64")]
2240 const MAX_DIGITS: usize = 20;
2242 #[cfg(target_pointer_width = "32")]
2243 const MAX_DIGITS: usize = 10;
2245 #[cfg(target_pointer_width = "16")]
2246 const MAX_DIGITS: usize = 5;
2249 for num_digits in 1..MAX_DIGITS {
2253 lim = lim.wrapping_mul(10);
2258 // We replace some characters so the CLI output is always consistent and underlines aligned.
2259 const OUTPUT_REPLACEMENTS: &[(char, &str)] = &[
2260 ('\t', " "), // We do our own tab replacement
2261 ('\u{200D}', ""), // Replace ZWJ with nothing for consistent terminal output of grapheme clusters.
2262 ('\u{202A}', ""), // The following unicode text flow control characters are inconsistently
2263 ('\u{202B}', ""), // supported across CLIs and can cause confusion due to the bytes on disk
2264 ('\u{202D}', ""), // not corresponding to the visible source code, so we replace them always.
2273 fn normalize_whitespace(str: &str) -> String {
2274 let mut s = str.to_string();
2275 for (c, replacement) in OUTPUT_REPLACEMENTS {
2276 s = s.replace(*c, replacement);
2281 fn draw_col_separator(buffer: &mut StyledBuffer, line: usize, col: usize) {
2282 buffer.puts(line, col, "| ", Style::LineNumber);
2285 fn draw_col_separator_no_space(buffer: &mut StyledBuffer, line: usize, col: usize) {
2286 draw_col_separator_no_space_with_style(buffer, line, col, Style::LineNumber);
2289 fn draw_col_separator_no_space_with_style(
2290 buffer: &mut StyledBuffer,
2295 buffer.putc(line, col, '|', style);
2299 buffer: &mut StyledBuffer,
2306 for col in col_from..col_to {
2307 buffer.putc(line, col, symbol, style);
2311 fn draw_note_separator(buffer: &mut StyledBuffer, line: usize, col: usize) {
2312 buffer.puts(line, col, "= ", Style::LineNumber);
2315 fn draw_multiline_line(
2316 buffer: &mut StyledBuffer,
2322 buffer.putc(line, offset + depth - 1, '|', style);
2332 let extra = if inclusive { 1 } else { 0 };
2333 (b_start..b_end + extra).contains(&a_start) || (a_start..a_end + extra).contains(&b_start)
2335 fn overlaps(a1: &Annotation, a2: &Annotation, padding: usize) -> bool {
2336 num_overlap(a1.start_col, a1.end_col + padding, a2.start_col, a2.end_col, false)
2339 fn emit_to_destination(
2340 rendered_buffer: &[Vec<StyledString>],
2342 dst: &mut Destination,
2343 short_message: bool,
2344 ) -> io::Result<()> {
2347 let mut dst = dst.writable();
2349 // In order to prevent error message interleaving, where multiple error lines get intermixed
2350 // when multiple compiler processes error simultaneously, we emit errors with additional
2353 // On Unix systems, we write into a buffered terminal rather than directly to a terminal. When
2354 // the .flush() is called we take the buffer created from the buffered writes and write it at
2355 // one shot. Because the Unix systems use ANSI for the colors, which is a text-based styling
2356 // scheme, this buffered approach works and maintains the styling.
2358 // On Windows, styling happens through calls to a terminal API. This prevents us from using the
2359 // same buffering approach. Instead, we use a global Windows mutex, which we acquire long
2360 // enough to output the full error message, then we release.
2361 let _buffer_lock = lock::acquire_global_lock("rustc_errors");
2362 for (pos, line) in rendered_buffer.iter().enumerate() {
2364 dst.apply_style(*lvl, part.style)?;
2365 write!(dst, "{}", part.text)?;
2368 if !short_message && (!lvl.is_failure_note() || pos != rendered_buffer.len() - 1) {
2376 pub enum Destination {
2377 Terminal(StandardStream),
2378 Buffered(BufferWriter),
2379 // The bool denotes whether we should be emitting ansi color codes or not
2380 Raw(Box<(dyn Write + Send)>, bool),
2383 pub enum WritableDst<'a> {
2384 Terminal(&'a mut StandardStream),
2385 Buffered(&'a mut BufferWriter, Buffer),
2386 Raw(&'a mut (dyn Write + Send)),
2387 ColoredRaw(Ansi<&'a mut (dyn Write + Send)>),
2391 fn from_stderr(color: ColorConfig) -> Destination {
2392 let choice = color.to_color_choice();
2393 // On Windows we'll be performing global synchronization on the entire
2394 // system for emitting rustc errors, so there's no need to buffer
2397 // On non-Windows we rely on the atomicity of `write` to ensure errors
2398 // don't get all jumbled up.
2400 Terminal(StandardStream::stderr(choice))
2402 Buffered(BufferWriter::stderr(choice))
2406 fn writable(&mut self) -> WritableDst<'_> {
2408 Destination::Terminal(ref mut t) => WritableDst::Terminal(t),
2409 Destination::Buffered(ref mut t) => {
2410 let buf = t.buffer();
2411 WritableDst::Buffered(t, buf)
2413 Destination::Raw(ref mut t, false) => WritableDst::Raw(t),
2414 Destination::Raw(ref mut t, true) => WritableDst::ColoredRaw(Ansi::new(t)),
2418 fn supports_color(&self) -> bool {
2420 Self::Terminal(ref stream) => stream.supports_color(),
2421 Self::Buffered(ref buffer) => buffer.buffer().supports_color(),
2422 Self::Raw(_, supports_color) => supports_color,
2427 impl<'a> WritableDst<'a> {
2428 fn apply_style(&mut self, lvl: Level, style: Style) -> io::Result<()> {
2429 let mut spec = ColorSpec::new();
2431 Style::Addition => {
2432 spec.set_fg(Some(Color::Green)).set_intense(true);
2435 spec.set_fg(Some(Color::Red)).set_intense(true);
2437 Style::LineAndColumn => {}
2438 Style::LineNumber => {
2439 spec.set_bold(true);
2440 spec.set_intense(true);
2442 spec.set_fg(Some(Color::Cyan));
2444 spec.set_fg(Some(Color::Blue));
2447 Style::Quotation => {}
2448 Style::MainHeaderMsg => {
2449 spec.set_bold(true);
2451 spec.set_intense(true).set_fg(Some(Color::White));
2454 Style::UnderlinePrimary | Style::LabelPrimary => {
2456 spec.set_bold(true);
2458 Style::UnderlineSecondary | Style::LabelSecondary => {
2459 spec.set_bold(true).set_intense(true);
2461 spec.set_fg(Some(Color::Cyan));
2463 spec.set_fg(Some(Color::Blue));
2466 Style::HeaderMsg | Style::NoStyle => {}
2467 Style::Level(lvl) => {
2469 spec.set_bold(true);
2471 Style::Highlight => {
2472 spec.set_bold(true);
2475 self.set_color(&spec)
2478 fn set_color(&mut self, color: &ColorSpec) -> io::Result<()> {
2480 WritableDst::Terminal(ref mut t) => t.set_color(color),
2481 WritableDst::Buffered(_, ref mut t) => t.set_color(color),
2482 WritableDst::ColoredRaw(ref mut t) => t.set_color(color),
2483 WritableDst::Raw(_) => Ok(()),
2487 fn reset(&mut self) -> io::Result<()> {
2489 WritableDst::Terminal(ref mut t) => t.reset(),
2490 WritableDst::Buffered(_, ref mut t) => t.reset(),
2491 WritableDst::ColoredRaw(ref mut t) => t.reset(),
2492 WritableDst::Raw(_) => Ok(()),
2497 impl<'a> Write for WritableDst<'a> {
2498 fn write(&mut self, bytes: &[u8]) -> io::Result<usize> {
2500 WritableDst::Terminal(ref mut t) => t.write(bytes),
2501 WritableDst::Buffered(_, ref mut buf) => buf.write(bytes),
2502 WritableDst::Raw(ref mut w) => w.write(bytes),
2503 WritableDst::ColoredRaw(ref mut t) => t.write(bytes),
2507 fn flush(&mut self) -> io::Result<()> {
2509 WritableDst::Terminal(ref mut t) => t.flush(),
2510 WritableDst::Buffered(_, ref mut buf) => buf.flush(),
2511 WritableDst::Raw(ref mut w) => w.flush(),
2512 WritableDst::ColoredRaw(ref mut w) => w.flush(),
2517 impl<'a> Drop for WritableDst<'a> {
2518 fn drop(&mut self) {
2519 if let WritableDst::Buffered(ref mut dst, ref mut buf) = self {
2520 drop(dst.print(buf));
2525 /// Whether the original and suggested code are visually similar enough to warrant extra wording.
2526 pub fn is_case_difference(sm: &SourceMap, suggested: &str, sp: Span) -> bool {
2527 // FIXME: this should probably be extended to also account for `FO0` → `FOO` and unicode.
2528 let found = match sm.span_to_snippet(sp) {
2529 Ok(snippet) => snippet,
2531 warn!(error = ?e, "Invalid span {:?}", sp);
2535 let ascii_confusables = &['c', 'f', 'i', 'k', 'o', 's', 'u', 'v', 'w', 'x', 'y', 'z'];
2536 // All the chars that differ in capitalization are confusable (above):
2537 let confusable = iter::zip(found.chars(), suggested.chars())
2538 .filter(|(f, s)| f != s)
2539 .all(|(f, s)| (ascii_confusables.contains(&f) || ascii_confusables.contains(&s)));
2540 confusable && found.to_lowercase() == suggested.to_lowercase()
2541 // FIXME: We sometimes suggest the same thing we already have, which is a
2542 // bug, but be defensive against that here.
2543 && found != suggested