1 //! The current rustc diagnostics emitter.
3 //! An `Emitter` takes care of generating the output from a `DiagnosticBuilder` struct.
5 //! There are various `Emitter` implementations that generate different output formats such as
6 //! JSON and human readable output.
8 //! The output types are defined in `rustc_session::config::ErrorOutputType`.
12 use rustc_span::source_map::SourceMap;
13 use rustc_span::{MultiSpan, SourceFile, Span};
15 use crate::snippet::{Annotation, AnnotationType, Line, MultilineAnnotation, Style, StyledString};
16 use crate::styled_buffer::StyledBuffer;
18 CodeSuggestion, Diagnostic, DiagnosticId, Handler, Level, SubDiagnostic, SubstitutionHighlight,
22 use rustc_lint_defs::pluralize;
24 use rustc_data_structures::fx::FxHashMap;
25 use rustc_data_structures::sync::Lrc;
26 use rustc_span::hygiene::{ExpnKind, MacroKind};
28 use std::cmp::{max, min, Reverse};
30 use std::io::prelude::*;
33 use termcolor::{Ansi, BufferWriter, ColorChoice, ColorSpec, StandardStream};
34 use termcolor::{Buffer, Color, WriteColor};
37 /// Default column width, used in tests and when terminal dimensions cannot be determined.
38 const DEFAULT_COLUMN_WIDTH: usize = 140;
40 /// Describes the way the content of the `rendered` field of the json output is generated
41 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
42 pub enum HumanReadableErrorType {
44 AnnotateSnippet(ColorConfig),
48 impl HumanReadableErrorType {
49 /// Returns a (`short`, `color`) tuple
50 pub fn unzip(self) -> (bool, ColorConfig) {
52 HumanReadableErrorType::Default(cc) => (false, cc),
53 HumanReadableErrorType::Short(cc) => (true, cc),
54 HumanReadableErrorType::AnnotateSnippet(cc) => (false, cc),
59 dst: Box<dyn Write + Send>,
60 source_map: Option<Lrc<SourceMap>>,
62 terminal_width: Option<usize>,
63 macro_backtrace: bool,
65 let (short, color_config) = self.unzip();
66 let color = color_config.suggests_using_colors();
67 EmitterWriter::new(dst, source_map, short, teach, color, terminal_width, macro_backtrace)
71 #[derive(Clone, Copy, Debug)]
73 /// The available whitespace in the left that can be consumed when centering.
74 pub whitespace_left: usize,
75 /// The column of the beginning of left-most span.
77 /// The column of the end of right-most span.
78 pub span_right: usize,
79 /// The beginning of the line to be displayed.
80 pub computed_left: usize,
81 /// The end of the line to be displayed.
82 pub computed_right: usize,
83 /// The current width of the terminal. Uses value of `DEFAULT_COLUMN_WIDTH` constant by default
85 pub column_width: usize,
86 /// The end column of a span label, including the span. Doesn't account for labels not in the
87 /// same line as the span.
88 pub label_right: usize,
93 whitespace_left: usize,
100 // The 6 is padding to give a bit of room for `...` when displaying:
105 // 16 | ... fn foo(self) -> Self::Bar {
110 whitespace_left: whitespace_left.saturating_sub(6),
111 span_left: span_left.saturating_sub(6),
112 span_right: span_right + 6,
116 label_right: label_right + 6,
118 m.compute(max_line_len);
122 fn was_cut_left(&self) -> bool {
123 self.computed_left > 0
126 fn was_cut_right(&self, line_len: usize) -> bool {
128 if self.computed_right == self.span_right || self.computed_right == self.label_right {
129 // Account for the "..." padding given above. Otherwise we end up with code lines that
130 // do fit but end in "..." as if they were trimmed.
131 self.computed_right - 6
135 right < line_len && self.computed_left + self.column_width < line_len
138 fn compute(&mut self, max_line_len: usize) {
139 // When there's a lot of whitespace (>20), we want to trim it as it is useless.
140 self.computed_left = if self.whitespace_left > 20 {
141 self.whitespace_left - 16 // We want some padding.
145 // We want to show as much as possible, max_line_len is the right-most boundary for the
147 self.computed_right = max(max_line_len, self.computed_left);
149 if self.computed_right - self.computed_left > self.column_width {
150 // Trimming only whitespace isn't enough, let's get craftier.
151 if self.label_right - self.whitespace_left <= self.column_width {
152 // Attempt to fit the code window only trimming whitespace.
153 self.computed_left = self.whitespace_left;
154 self.computed_right = self.computed_left + self.column_width;
155 } else if self.label_right - self.span_left <= self.column_width {
156 // Attempt to fit the code window considering only the spans and labels.
157 let padding_left = (self.column_width - (self.label_right - self.span_left)) / 2;
158 self.computed_left = self.span_left.saturating_sub(padding_left);
159 self.computed_right = self.computed_left + self.column_width;
160 } else if self.span_right - self.span_left <= self.column_width {
161 // Attempt to fit the code window considering the spans and labels plus padding.
162 let padding_left = (self.column_width - (self.span_right - self.span_left)) / 5 * 2;
163 self.computed_left = self.span_left.saturating_sub(padding_left);
164 self.computed_right = self.computed_left + self.column_width;
166 // Mostly give up but still don't show the full line.
167 self.computed_left = self.span_left;
168 self.computed_right = self.span_right;
173 fn left(&self, line_len: usize) -> usize {
174 min(self.computed_left, line_len)
177 fn right(&self, line_len: usize) -> usize {
178 if line_len.saturating_sub(self.computed_left) <= self.column_width {
181 min(line_len, self.computed_right)
186 const ANONYMIZED_LINE_NUM: &str = "LL";
188 /// Emitter trait for emitting errors.
190 /// Emit a structured diagnostic.
191 fn emit_diagnostic(&mut self, diag: &Diagnostic);
193 /// Emit a notification that an artifact has been output.
194 /// This is currently only supported for the JSON format,
195 /// other formats can, and will, simply ignore it.
196 fn emit_artifact_notification(&mut self, _path: &Path, _artifact_type: &str) {}
198 fn emit_future_breakage_report(&mut self, _diags: Vec<Diagnostic>) {}
200 /// Emit list of unused externs
201 fn emit_unused_externs(&mut self, _lint_level: &str, _unused_externs: &[&str]) {}
203 /// Checks if should show explanations about "rustc --explain"
204 fn should_show_explain(&self) -> bool {
208 /// Checks if we can use colors in the current output stream.
209 fn supports_color(&self) -> bool {
213 fn source_map(&self) -> Option<&Lrc<SourceMap>>;
215 /// Formats the substitutions of the primary_span
217 /// The are a lot of conditions to this method, but in short:
219 /// * If the current `Diagnostic` has only one visible `CodeSuggestion`,
220 /// we format the `help` suggestion depending on the content of the
221 /// substitutions. In that case, we return the modified span only.
223 /// * If the current `Diagnostic` has multiple suggestions,
224 /// we return the original `primary_span` and the original suggestions.
225 fn primary_span_formatted<'a>(
227 diag: &'a Diagnostic,
228 ) -> (MultiSpan, &'a [CodeSuggestion]) {
229 let mut primary_span = diag.span.clone();
230 if let Some((sugg, rest)) = diag.suggestions.split_first() {
231 if rest.is_empty() &&
232 // ^ if there is only one suggestion
233 // don't display multi-suggestions as labels
234 sugg.substitutions.len() == 1 &&
235 // don't display multipart suggestions as labels
236 sugg.substitutions[0].parts.len() == 1 &&
237 // don't display long messages as labels
238 sugg.msg.split_whitespace().count() < 10 &&
239 // don't display multiline suggestions as labels
240 !sugg.substitutions[0].parts[0].snippet.contains('\n') &&
242 // when this style is set we want the suggestion to be a message, not inline
243 SuggestionStyle::HideCodeAlways,
244 // trivial suggestion for tooling's sake, never shown
245 SuggestionStyle::CompletelyHidden,
246 // subtle suggestion, never shown inline
247 SuggestionStyle::ShowAlways,
248 ].contains(&sugg.style)
250 let substitution = &sugg.substitutions[0].parts[0].snippet.trim();
251 let msg = if substitution.is_empty() || sugg.style.hide_inline() {
252 // This substitution is only removal OR we explicitly don't want to show the
253 // code inline (`hide_inline`). Therefore, we don't show the substitution.
254 format!("help: {}", sugg.msg)
256 // Show the default suggestion text with the substitution
262 .map(|sm| is_case_difference(
265 sugg.substitutions[0].parts[0].span,
269 " (notice the capitalization)"
276 primary_span.push_span_label(sugg.substitutions[0].parts[0].span, msg);
278 // We return only the modified primary_span
281 // if there are multiple suggestions, print them all in full
282 // to be consistent. We could try to figure out if we can
283 // make one (or the first one) inline, but that would give
284 // undue importance to a semi-random suggestion
285 (primary_span, &diag.suggestions)
288 (primary_span, &diag.suggestions)
292 fn fix_multispans_in_extern_macros_and_render_macro_backtrace(
294 source_map: &Option<Lrc<SourceMap>>,
295 span: &mut MultiSpan,
296 children: &mut Vec<SubDiagnostic>,
300 // Check for spans in macros, before `fix_multispans_in_extern_macros`
301 // has a chance to replace them.
302 let has_macro_spans = iter::once(&*span)
303 .chain(children.iter().map(|child| &child.span))
304 .flat_map(|span| span.primary_spans())
305 .flat_map(|sp| sp.macro_backtrace())
306 .find_map(|expn_data| {
307 match expn_data.kind {
308 ExpnKind::Root => None,
310 // Skip past non-macro entries, just in case there
311 // are some which do actually involve macros.
312 ExpnKind::Inlined | ExpnKind::Desugaring(..) | ExpnKind::AstPass(..) => None,
314 ExpnKind::Macro(macro_kind, name) => Some((macro_kind, name)),
319 self.fix_multispans_in_extern_macros(source_map, span, children);
322 self.render_multispans_macro_backtrace(span, children, backtrace);
325 if let Some((macro_kind, name)) = has_macro_spans {
326 let descr = macro_kind.descr();
329 "this {level} originates in the {descr} `{name}` \
330 (in Nightly builds, run with -Z macro-backtrace for more info)",
333 children.push(SubDiagnostic {
335 message: vec![(msg, Style::NoStyle)],
336 span: MultiSpan::new(),
343 fn render_multispans_macro_backtrace(
345 span: &mut MultiSpan,
346 children: &mut Vec<SubDiagnostic>,
349 for span in iter::once(span).chain(children.iter_mut().map(|child| &mut child.span)) {
350 self.render_multispan_macro_backtrace(span, backtrace);
354 fn render_multispan_macro_backtrace(&self, span: &mut MultiSpan, always_backtrace: bool) {
355 let mut new_labels: Vec<(Span, String)> = vec![];
357 for &sp in span.primary_spans() {
362 // FIXME(eddyb) use `retain` on `macro_backtrace` to remove all the
363 // entries we don't want to print, to make sure the indices being
364 // printed are contiguous (or omitted if there's only one entry).
365 let macro_backtrace: Vec<_> = sp.macro_backtrace().collect();
366 for (i, trace) in macro_backtrace.iter().rev().enumerate() {
367 if trace.def_site.is_dummy() {
371 if always_backtrace && !matches!(trace.kind, ExpnKind::Inlined) {
375 "in this expansion of `{}`{}",
377 if macro_backtrace.len() > 1 {
378 // if macro_backtrace.len() == 1 it'll be
379 // pointed at by "in this macro invocation"
380 format!(" (#{})", i + 1)
388 // Don't add a label on the call site if the diagnostic itself
389 // already points to (a part of) that call site, as the label
390 // is meant for showing the relevant invocation when the actual
391 // diagnostic is pointing to some part of macro definition.
393 // This also handles the case where an external span got replaced
394 // with the call site span by `fix_multispans_in_extern_macros`.
396 // NB: `-Zmacro-backtrace` overrides this, for uniformity, as the
397 // "in this expansion of" label above is always added in that mode,
398 // and it needs an "in this macro invocation" label to match that.
399 let redundant_span = trace.call_site.contains(sp);
401 if !redundant_span || always_backtrace {
402 let msg: Cow<'static, _> = match trace.kind {
403 ExpnKind::Macro(MacroKind::Attr, _) => {
404 "this procedural macro expansion".into()
406 ExpnKind::Macro(MacroKind::Derive, _) => {
407 "this derive macro expansion".into()
409 ExpnKind::Macro(MacroKind::Bang, _) => "this macro invocation".into(),
410 ExpnKind::Inlined => "the inlined copy of this code".into(),
411 ExpnKind::Root => "in the crate root".into(),
412 ExpnKind::AstPass(kind) => kind.descr().into(),
413 ExpnKind::Desugaring(kind) => {
414 format!("this {} desugaring", kind.descr()).into()
422 if macro_backtrace.len() > 1 && always_backtrace {
423 // only specify order when the macro
424 // backtrace is multiple levels deep
425 format!(" (#{})", i + 1)
432 if !always_backtrace {
438 for (label_span, label_text) in new_labels {
439 span.push_span_label(label_span, label_text);
443 // This does a small "fix" for multispans by looking to see if it can find any that
444 // point directly at external macros. Since these are often difficult to read,
445 // this will change the span to point at the use site.
446 fn fix_multispans_in_extern_macros(
448 source_map: &Option<Lrc<SourceMap>>,
449 span: &mut MultiSpan,
450 children: &mut Vec<SubDiagnostic>,
452 let source_map = if let Some(ref sm) = source_map {
457 debug!("fix_multispans_in_extern_macros: before: span={:?} children={:?}", span, children);
458 self.fix_multispan_in_extern_macros(source_map, span);
459 for child in children.iter_mut() {
460 self.fix_multispan_in_extern_macros(source_map, &mut child.span);
462 debug!("fix_multispans_in_extern_macros: after: span={:?} children={:?}", span, children);
465 // This "fixes" MultiSpans that contain `Span`s pointing to locations inside of external macros.
466 // Since these locations are often difficult to read,
467 // we move these spans from the external macros to their corresponding use site.
468 fn fix_multispan_in_extern_macros(&self, source_map: &Lrc<SourceMap>, span: &mut MultiSpan) {
469 // First, find all the spans in external macros and point instead at their use site.
470 let replacements: Vec<(Span, Span)> = span
474 .chain(span.span_labels().iter().map(|sp_label| sp_label.span))
476 if !sp.is_dummy() && source_map.is_imported(sp) {
477 let maybe_callsite = sp.source_callsite();
478 if sp != maybe_callsite {
479 return Some((sp, maybe_callsite));
486 // After we have them, make sure we replace these 'bad' def sites with their use sites.
487 for (from, to) in replacements {
488 span.replace(from, to);
493 impl Emitter for EmitterWriter {
494 fn source_map(&self) -> Option<&Lrc<SourceMap>> {
498 fn emit_diagnostic(&mut self, diag: &Diagnostic) {
499 let mut children = diag.children.clone();
500 let (mut primary_span, suggestions) = self.primary_span_formatted(&diag);
501 debug!("emit_diagnostic: suggestions={:?}", suggestions);
503 self.fix_multispans_in_extern_macros_and_render_macro_backtrace(
508 self.macro_backtrace,
511 self.emit_messages_default(
513 &diag.styled_message(),
521 fn should_show_explain(&self) -> bool {
525 fn supports_color(&self) -> bool {
526 self.dst.supports_color()
530 /// An emitter that does nothing when emitting a non-fatal diagnostic.
531 /// Fatal diagnostics are forwarded to `fatal_handler` to avoid silent
532 /// failures of rustc, as witnessed e.g. in issue #89358.
533 pub struct SilentEmitter {
534 pub fatal_handler: Handler,
535 pub fatal_note: Option<String>,
538 impl Emitter for SilentEmitter {
539 fn source_map(&self) -> Option<&Lrc<SourceMap>> {
542 fn emit_diagnostic(&mut self, d: &Diagnostic) {
543 if d.level == Level::Fatal {
544 let mut d = d.clone();
545 if let Some(ref note) = self.fatal_note {
548 self.fatal_handler.emit_diagnostic(&d);
553 /// Maximum number of lines we will print for a multiline suggestion; arbitrary.
555 /// This should be replaced with a more involved mechanism to output multiline suggestions that
556 /// more closely mimics the regular diagnostic output, where irrelevant code lines are elided.
557 pub const MAX_SUGGESTION_HIGHLIGHT_LINES: usize = 6;
558 /// Maximum number of suggestions to be shown
560 /// Arbitrary, but taken from trait import suggestion limit
561 pub const MAX_SUGGESTIONS: usize = 4;
563 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
564 pub enum ColorConfig {
571 fn to_color_choice(self) -> ColorChoice {
573 ColorConfig::Always => {
574 if atty::is(atty::Stream::Stderr) {
577 ColorChoice::AlwaysAnsi
580 ColorConfig::Never => ColorChoice::Never,
581 ColorConfig::Auto if atty::is(atty::Stream::Stderr) => ColorChoice::Auto,
582 ColorConfig::Auto => ColorChoice::Never,
585 fn suggests_using_colors(self) -> bool {
587 ColorConfig::Always | ColorConfig::Auto => true,
588 ColorConfig::Never => false,
593 /// Handles the writing of `HumanReadableErrorType::Default` and `HumanReadableErrorType::Short`
594 pub struct EmitterWriter {
596 sm: Option<Lrc<SourceMap>>,
600 terminal_width: Option<usize>,
602 macro_backtrace: bool,
606 pub struct FileWithAnnotatedLines {
607 pub file: Lrc<SourceFile>,
608 pub lines: Vec<Line>,
609 multiline_depth: usize,
614 color_config: ColorConfig,
615 source_map: Option<Lrc<SourceMap>>,
618 terminal_width: Option<usize>,
619 macro_backtrace: bool,
621 let dst = Destination::from_stderr(color_config);
634 dst: Box<dyn Write + Send>,
635 source_map: Option<Lrc<SourceMap>>,
639 terminal_width: Option<usize>,
640 macro_backtrace: bool,
643 dst: Raw(dst, colored),
653 pub fn ui_testing(mut self, ui_testing: bool) -> Self {
654 self.ui_testing = ui_testing;
658 fn maybe_anonymized(&self, line_num: usize) -> String {
659 if self.ui_testing { ANONYMIZED_LINE_NUM.to_string() } else { line_num.to_string() }
664 buffer: &mut StyledBuffer,
672 // Tabs are assumed to have been replaced by spaces in calling code.
673 debug_assert!(!source_string.contains('\t'));
674 let line_len = source_string.len();
675 // Create the source line we will highlight.
676 let left = margin.left(line_len);
677 let right = margin.right(line_len);
678 // On long lines, we strip the source line, accounting for unicode.
680 let code: String = source_string
684 // Make sure that the trimming on the right will fall within the terminal width.
685 // FIXME: `unicode_width` sometimes disagrees with terminals on how wide a `char` is.
686 // For now, just accept that sometimes the code line will be longer than desired.
687 let next = unicode_width::UnicodeWidthChar::width(*ch).unwrap_or(1);
688 if taken + next > right - left {
695 buffer.puts(line_offset, code_offset, &code, Style::Quotation);
696 if margin.was_cut_left() {
697 // We have stripped some code/whitespace from the beginning, make it clear.
698 buffer.puts(line_offset, code_offset, "...", Style::LineNumber);
700 if margin.was_cut_right(line_len) {
701 // We have stripped some code after the right-most span end, make it clear we did so.
702 buffer.puts(line_offset, code_offset + taken - 3, "...", Style::LineNumber);
704 buffer.puts(line_offset, 0, &self.maybe_anonymized(line_index), Style::LineNumber);
706 draw_col_separator(buffer, line_offset, width_offset - 2);
709 fn render_source_line(
711 buffer: &mut StyledBuffer,
712 file: Lrc<SourceFile>,
717 ) -> Vec<(usize, Style)> {
723 // | secondary span label
725 // ^^ ^ ^^^ ^^^^ ^^^ we don't care about code too far to the right of a span, we trim it
727 // | | | actual code found in your source code and the spans we use to mark it
728 // | | when there's too much wasted space to the left, trim it
729 // | vertical divider between the column number and the code
732 if line.line_index == 0 {
736 let source_string = match file.get_line(line.line_index - 1) {
737 Some(s) => replace_tabs(&*s),
738 None => return Vec::new(),
741 let line_offset = buffer.num_lines();
743 let left = margin.left(source_string.len()); // Left trim
744 // Account for unicode characters of width !=0 that were removed.
745 let left = source_string
748 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
761 // Special case when there's only one annotation involved, it is the start of a multiline
762 // span and there's no text at the beginning of the code line. Instead of doing the whole
771 // we simplify the output to:
777 if let [ann] = &line.annotations[..] {
778 if let AnnotationType::MultilineStart(depth) = ann.annotation_type {
779 if source_string.chars().take(ann.start_col).all(|c| c.is_whitespace()) {
780 let style = if ann.is_primary {
781 Style::UnderlinePrimary
783 Style::UnderlineSecondary
785 buffer.putc(line_offset, width_offset + depth - 1, '/', style);
786 return vec![(depth, style)];
791 // We want to display like this:
793 // vec.push(vec.pop().unwrap());
794 // --- ^^^ - previous borrow ends here
796 // | error occurs here
797 // previous borrow of `vec` occurs here
799 // But there are some weird edge cases to be aware of:
801 // vec.push(vec.pop().unwrap());
802 // -------- - previous borrow ends here
804 // |this makes no sense
805 // previous borrow of `vec` occurs here
807 // For this reason, we group the lines into "highlight lines"
808 // and "annotations lines", where the highlight lines have the `^`.
810 // Sort the annotations by (start, end col)
811 // The labels are reversed, sort and then reversed again.
812 // Consider a list of annotations (A1, A2, C1, C2, B1, B2) where
813 // the letter signifies the span. Here we are only sorting by the
814 // span and hence, the order of the elements with the same span will
815 // not change. On reversing the ordering (|a, b| but b.cmp(a)), you get
816 // (C1, C2, B1, B2, A1, A2). All the elements with the same span are
817 // still ordered first to last, but all the elements with different
818 // spans are ordered by their spans in last to first order. Last to
819 // first order is important, because the jiggly lines and | are on
820 // the left, so the rightmost span needs to be rendered first,
821 // otherwise the lines would end up needing to go over a message.
823 let mut annotations = line.annotations.clone();
824 annotations.sort_by_key(|a| Reverse(a.start_col));
826 // First, figure out where each label will be positioned.
828 // In the case where you have the following annotations:
830 // vec.push(vec.pop().unwrap());
831 // -------- - previous borrow ends here [C]
833 // |this makes no sense [B]
834 // previous borrow of `vec` occurs here [A]
836 // `annotations_position` will hold [(2, A), (1, B), (0, C)].
838 // We try, when possible, to stick the rightmost annotation at the end
839 // of the highlight line:
841 // vec.push(vec.pop().unwrap());
842 // --- --- - previous borrow ends here
844 // But sometimes that's not possible because one of the other
845 // annotations overlaps it. For example, from the test
846 // `span_overlap_label`, we have the following annotations
847 // (written on distinct lines for clarity):
853 // In this case, we can't stick the rightmost-most label on
854 // the highlight line, or we would get:
861 // which is totally weird. Instead we want:
869 // which is...less weird, at least. In fact, in general, if
870 // the rightmost span overlaps with any other span, we should
871 // use the "hang below" version, so we can at least make it
872 // clear where the span *starts*. There's an exception for this
873 // logic, when the labels do not have a message:
888 let mut annotations_position = vec![];
889 let mut line_len = 0;
891 for (i, annotation) in annotations.iter().enumerate() {
892 for (j, next) in annotations.iter().enumerate() {
893 if overlaps(next, annotation, 0) // This label overlaps with another one and both
894 && annotation.has_label() // take space (they have text and are not
895 && j > i // multiline lines).
897 // We're currently on the first line, move the label one line down
899 // If we're overlapping with an un-labelled annotation with the same span
900 // we can just merge them in the output
901 if next.start_col == annotation.start_col
902 && next.end_col == annotation.end_col
908 // This annotation needs a new line in the output.
913 annotations_position.push((p, annotation));
914 for (j, next) in annotations.iter().enumerate() {
916 let l = next.label.as_ref().map_or(0, |label| label.len() + 2);
917 if (overlaps(next, annotation, l) // Do not allow two labels to be in the same
918 // line if they overlap including padding, to
919 // avoid situations like:
926 && annotation.has_label() // Both labels must have some text, otherwise
927 && next.has_label()) // they are not overlapping.
928 // Do not add a new line if this annotation
929 // or the next are vertical line placeholders.
930 || (annotation.takes_space() // If either this or the next annotation is
931 && next.has_label()) // multiline start/end, move it to a new line
932 || (annotation.has_label() // so as not to overlap the horizontal lines.
933 && next.takes_space())
934 || (annotation.takes_space() && next.takes_space())
935 || (overlaps(next, annotation, l)
936 && next.end_col <= annotation.end_col
941 // This annotation needs a new line in the output.
947 line_len = max(line_len, p);
954 // If there are no annotations or the only annotations on this line are
955 // MultilineLine, then there's only code being shown, stop processing.
956 if line.annotations.iter().all(|a| a.is_line()) {
960 // Write the column separator.
962 // After this we will have:
971 for pos in 0..=line_len {
972 draw_col_separator(buffer, line_offset + pos + 1, width_offset - 2);
975 // Write the horizontal lines for multiline annotations
976 // (only the first and last lines need this).
978 // After this we will have:
987 for &(pos, annotation) in &annotations_position {
988 let style = if annotation.is_primary {
989 Style::UnderlinePrimary
991 Style::UnderlineSecondary
994 match annotation.annotation_type {
995 AnnotationType::MultilineStart(depth) | AnnotationType::MultilineEnd(depth) => {
1000 width_offset + depth,
1001 (code_offset + annotation.start_col).saturating_sub(left),
1005 _ if self.teach => {
1006 buffer.set_style_range(
1008 (code_offset + annotation.start_col).saturating_sub(left),
1009 (code_offset + annotation.end_col).saturating_sub(left),
1011 annotation.is_primary,
1018 // Write the vertical lines for labels that are on a different line as the underline.
1020 // After this we will have:
1029 for &(pos, annotation) in &annotations_position {
1030 let style = if annotation.is_primary {
1031 Style::UnderlinePrimary
1033 Style::UnderlineSecondary
1037 if pos > 1 && (annotation.has_label() || annotation.takes_space()) {
1038 for p in line_offset + 1..=line_offset + pos {
1041 (code_offset + annotation.start_col).saturating_sub(left),
1047 match annotation.annotation_type {
1048 AnnotationType::MultilineStart(depth) => {
1049 for p in line_offset + pos + 1..line_offset + line_len + 2 {
1050 buffer.putc(p, width_offset + depth - 1, '|', style);
1053 AnnotationType::MultilineEnd(depth) => {
1054 for p in line_offset..=line_offset + pos {
1055 buffer.putc(p, width_offset + depth - 1, '|', style);
1062 // Write the labels on the annotations that actually have a label.
1064 // After this we will have:
1069 // | something about `foo`
1073 for &(pos, annotation) in &annotations_position {
1075 if annotation.is_primary { Style::LabelPrimary } else { Style::LabelSecondary };
1076 let (pos, col) = if pos == 0 {
1077 (pos + 1, (annotation.end_col + 1).saturating_sub(left))
1079 (pos + 2, annotation.start_col.saturating_sub(left))
1081 if let Some(ref label) = annotation.label {
1082 buffer.puts(line_offset + pos, code_offset + col, &label, style);
1086 // Sort from biggest span to smallest span so that smaller spans are
1087 // represented in the output:
1092 // | | something about `foo`
1093 // | something about `fn foo()`
1094 annotations_position.sort_by_key(|(_, ann)| {
1095 // Decreasing order. When annotations share the same length, prefer `Primary`.
1096 (Reverse(ann.len()), ann.is_primary)
1099 // Write the underlines.
1101 // After this we will have:
1106 // | something about `foo`
1110 for &(_, annotation) in &annotations_position {
1111 let (underline, style) = if annotation.is_primary {
1112 ('^', Style::UnderlinePrimary)
1114 ('-', Style::UnderlineSecondary)
1116 for p in annotation.start_col..annotation.end_col {
1119 (code_offset + p).saturating_sub(left),
1125 annotations_position
1127 .filter_map(|&(_, annotation)| match annotation.annotation_type {
1128 AnnotationType::MultilineStart(p) | AnnotationType::MultilineEnd(p) => {
1129 let style = if annotation.is_primary {
1132 Style::LabelSecondary
1138 .collect::<Vec<_>>()
1141 fn get_multispan_max_line_num(&mut self, msp: &MultiSpan) -> usize {
1142 let sm = match self.sm {
1148 for primary_span in msp.primary_spans() {
1149 if !primary_span.is_dummy() {
1150 let hi = sm.lookup_char_pos(primary_span.hi());
1151 max = (hi.line).max(max);
1154 if !self.short_message {
1155 for span_label in msp.span_labels() {
1156 if !span_label.span.is_dummy() {
1157 let hi = sm.lookup_char_pos(span_label.span.hi());
1158 max = (hi.line).max(max);
1166 fn get_max_line_num(&mut self, span: &MultiSpan, children: &[SubDiagnostic]) -> usize {
1167 let primary = self.get_multispan_max_line_num(span);
1170 .map(|sub| self.get_multispan_max_line_num(&sub.span))
1176 /// Adds a left margin to every line but the first, given a padding length and the label being
1177 /// displayed, keeping the provided highlighting.
1180 buffer: &mut StyledBuffer,
1181 msg: &[(String, Style)],
1184 override_style: Option<Style>,
1186 // The extra 5 ` ` is padding that's always needed to align to the `note: `:
1189 // --> file.rs:13:20
1194 // = note: multiline
1199 // | | length of label
1201 // `max_line_num_len`
1202 let padding = " ".repeat(padding + label.len() + 5);
1204 /// Returns `override` if it is present and `style` is `NoStyle` or `style` otherwise
1205 fn style_or_override(style: Style, override_: Option<Style>) -> Style {
1206 match (style, override_) {
1207 (Style::NoStyle, Some(override_)) => override_,
1212 let mut line_number = 0;
1214 // Provided the following diagnostic message:
1218 // ("highlighted multiline\nstring to\nsee how it ", Style::NoStyle),
1219 // ("looks", Style::Highlight),
1220 // ("with\nvery ", Style::NoStyle),
1221 // ("weird", Style::Highlight),
1222 // (" formats\n", Style::NoStyle),
1223 // ("see?", Style::Highlight),
1226 // the expected output on a note is (* surround the highlighted text)
1228 // = note: highlighted multiline
1230 // see how it *looks* with
1231 // very *weird* formats
1233 for &(ref text, ref style) in msg.iter() {
1234 let lines = text.split('\n').collect::<Vec<_>>();
1235 if lines.len() > 1 {
1236 for (i, line) in lines.iter().enumerate() {
1239 buffer.append(line_number, &padding, Style::NoStyle);
1241 buffer.append(line_number, line, style_or_override(*style, override_style));
1244 buffer.append(line_number, text, style_or_override(*style, override_style));
1249 fn emit_message_default(
1252 msg: &[(String, Style)],
1253 code: &Option<DiagnosticId>,
1255 max_line_num_len: usize,
1257 ) -> io::Result<()> {
1258 let mut buffer = StyledBuffer::new();
1260 if !msp.has_primary_spans() && !msp.has_span_labels() && is_secondary && !self.short_message
1262 // This is a secondary message with no span info
1263 for _ in 0..max_line_num_len {
1264 buffer.prepend(0, " ", Style::NoStyle);
1266 draw_note_separator(&mut buffer, 0, max_line_num_len + 1);
1267 if *level != Level::FailureNote {
1268 buffer.append(0, level.to_str(), Style::MainHeaderMsg);
1269 buffer.append(0, ": ", Style::NoStyle);
1271 self.msg_to_buffer(&mut buffer, msg, max_line_num_len, "note", None);
1273 // The failure note level itself does not provide any useful diagnostic information
1274 if *level != Level::FailureNote {
1275 buffer.append(0, level.to_str(), Style::Level(*level));
1277 // only render error codes, not lint codes
1278 if let Some(DiagnosticId::Error(ref code)) = *code {
1279 buffer.append(0, "[", Style::Level(*level));
1280 buffer.append(0, &code, Style::Level(*level));
1281 buffer.append(0, "]", Style::Level(*level));
1283 let header_style = if is_secondary { Style::HeaderMsg } else { Style::MainHeaderMsg };
1284 if *level != Level::FailureNote {
1285 buffer.append(0, ": ", header_style);
1287 for &(ref text, _) in msg.iter() {
1288 buffer.append(0, &replace_tabs(text), header_style);
1292 let mut annotated_files = FileWithAnnotatedLines::collect_annotations(msp, &self.sm);
1294 // Make sure our primary file comes first
1295 let (primary_lo, sm) = if let (Some(sm), Some(ref primary_span)) =
1296 (self.sm.as_ref(), msp.primary_span().as_ref())
1298 if !primary_span.is_dummy() {
1299 (sm.lookup_char_pos(primary_span.lo()), sm)
1301 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1305 // If we don't have span information, emit and exit
1306 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1310 annotated_files.binary_search_by(|x| x.file.name.cmp(&primary_lo.file.name))
1312 annotated_files.swap(0, pos);
1315 // Print out the annotate source lines that correspond with the error
1316 for annotated_file in annotated_files {
1317 // we can't annotate anything if the source is unavailable.
1318 if !sm.ensure_source_file_source_present(annotated_file.file.clone()) {
1322 // print out the span location and spacer before we print the annotated source
1323 // to do this, we need to know if this span will be primary
1324 let is_primary = primary_lo.file.name == annotated_file.file.name;
1326 let loc = primary_lo.clone();
1327 if !self.short_message {
1328 // remember where we are in the output buffer for easy reference
1329 let buffer_msg_line_offset = buffer.num_lines();
1331 buffer.prepend(buffer_msg_line_offset, "--> ", Style::LineNumber);
1333 buffer_msg_line_offset,
1336 sm.filename_for_diagnostics(&loc.file.name),
1337 sm.doctest_offset_line(&loc.file.name, loc.line),
1340 Style::LineAndColumn,
1342 for _ in 0..max_line_num_len {
1343 buffer.prepend(buffer_msg_line_offset, " ", Style::NoStyle);
1350 sm.filename_for_diagnostics(&loc.file.name),
1351 sm.doctest_offset_line(&loc.file.name, loc.line),
1354 Style::LineAndColumn,
1357 } else if !self.short_message {
1358 // remember where we are in the output buffer for easy reference
1359 let buffer_msg_line_offset = buffer.num_lines();
1362 draw_col_separator_no_space(
1364 buffer_msg_line_offset,
1365 max_line_num_len + 1,
1368 // Then, the secondary file indicator
1369 buffer.prepend(buffer_msg_line_offset + 1, "::: ", Style::LineNumber);
1370 let loc = if let Some(first_line) = annotated_file.lines.first() {
1371 let col = if let Some(first_annotation) = first_line.annotations.first() {
1372 format!(":{}", first_annotation.start_col + 1)
1378 sm.filename_for_diagnostics(&annotated_file.file.name),
1379 sm.doctest_offset_line(&annotated_file.file.name, first_line.line_index),
1383 format!("{}", sm.filename_for_diagnostics(&annotated_file.file.name))
1385 buffer.append(buffer_msg_line_offset + 1, &loc, Style::LineAndColumn);
1386 for _ in 0..max_line_num_len {
1387 buffer.prepend(buffer_msg_line_offset + 1, " ", Style::NoStyle);
1391 if !self.short_message {
1392 // Put in the spacer between the location and annotated source
1393 let buffer_msg_line_offset = buffer.num_lines();
1394 draw_col_separator_no_space(
1396 buffer_msg_line_offset,
1397 max_line_num_len + 1,
1400 // Contains the vertical lines' positions for active multiline annotations
1401 let mut multilines = FxHashMap::default();
1403 // Get the left-side margin to remove it
1404 let mut whitespace_margin = usize::MAX;
1405 for line_idx in 0..annotated_file.lines.len() {
1406 let file = annotated_file.file.clone();
1407 let line = &annotated_file.lines[line_idx];
1408 if let Some(source_string) = file.get_line(line.line_index - 1) {
1409 let leading_whitespace = source_string
1411 .take_while(|c| c.is_whitespace())
1414 // Tabs are displayed as 4 spaces
1420 if source_string.chars().any(|c| !c.is_whitespace()) {
1421 whitespace_margin = min(whitespace_margin, leading_whitespace);
1425 if whitespace_margin == usize::MAX {
1426 whitespace_margin = 0;
1429 // Left-most column any visible span points at.
1430 let mut span_left_margin = usize::MAX;
1431 for line in &annotated_file.lines {
1432 for ann in &line.annotations {
1433 span_left_margin = min(span_left_margin, ann.start_col);
1434 span_left_margin = min(span_left_margin, ann.end_col);
1437 if span_left_margin == usize::MAX {
1438 span_left_margin = 0;
1441 // Right-most column any visible span points at.
1442 let mut span_right_margin = 0;
1443 let mut label_right_margin = 0;
1444 let mut max_line_len = 0;
1445 for line in &annotated_file.lines {
1448 annotated_file.file.get_line(line.line_index - 1).map_or(0, |s| s.len()),
1450 for ann in &line.annotations {
1451 span_right_margin = max(span_right_margin, ann.start_col);
1452 span_right_margin = max(span_right_margin, ann.end_col);
1453 // FIXME: account for labels not in the same line
1454 let label_right = ann.label.as_ref().map_or(0, |l| l.len() + 1);
1455 label_right_margin = max(label_right_margin, ann.end_col + label_right);
1459 let width_offset = 3 + max_line_num_len;
1460 let code_offset = if annotated_file.multiline_depth == 0 {
1463 width_offset + annotated_file.multiline_depth + 1
1466 let column_width = if let Some(width) = self.terminal_width {
1467 width.saturating_sub(code_offset)
1468 } else if self.ui_testing {
1469 DEFAULT_COLUMN_WIDTH
1471 termize::dimensions()
1472 .map(|(w, _)| w.saturating_sub(code_offset))
1473 .unwrap_or(DEFAULT_COLUMN_WIDTH)
1476 let margin = Margin::new(
1485 // Next, output the annotate source for this file
1486 for line_idx in 0..annotated_file.lines.len() {
1487 let previous_buffer_line = buffer.num_lines();
1489 let depths = self.render_source_line(
1491 annotated_file.file.clone(),
1492 &annotated_file.lines[line_idx],
1498 let mut to_add = FxHashMap::default();
1500 for (depth, style) in depths {
1501 if multilines.remove(&depth).is_none() {
1502 to_add.insert(depth, style);
1506 // Set the multiline annotation vertical lines to the left of
1507 // the code in this line.
1508 for (depth, style) in &multilines {
1509 for line in previous_buffer_line..buffer.num_lines() {
1510 draw_multiline_line(&mut buffer, line, width_offset, *depth, *style);
1513 // check to see if we need to print out or elide lines that come between
1514 // this annotated line and the next one.
1515 if line_idx < (annotated_file.lines.len() - 1) {
1516 let line_idx_delta = annotated_file.lines[line_idx + 1].line_index
1517 - annotated_file.lines[line_idx].line_index;
1518 if line_idx_delta > 2 {
1519 let last_buffer_line_num = buffer.num_lines();
1520 buffer.puts(last_buffer_line_num, 0, "...", Style::LineNumber);
1522 // Set the multiline annotation vertical lines on `...` bridging line.
1523 for (depth, style) in &multilines {
1524 draw_multiline_line(
1526 last_buffer_line_num,
1532 } else if line_idx_delta == 2 {
1533 let unannotated_line = annotated_file
1535 .get_line(annotated_file.lines[line_idx].line_index)
1536 .unwrap_or_else(|| Cow::from(""));
1538 let last_buffer_line_num = buffer.num_lines();
1542 &replace_tabs(&unannotated_line),
1543 annotated_file.lines[line_idx + 1].line_index - 1,
1544 last_buffer_line_num,
1550 for (depth, style) in &multilines {
1551 draw_multiline_line(
1553 last_buffer_line_num,
1562 multilines.extend(&to_add);
1567 // final step: take our styled buffer, render it, then output it
1568 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1573 fn emit_suggestion_default(
1575 suggestion: &CodeSuggestion,
1577 max_line_num_len: usize,
1578 ) -> io::Result<()> {
1579 let sm = match self.sm {
1581 None => return Ok(()),
1584 // Render the replacements for each suggestion
1585 let suggestions = suggestion.splice_lines(&**sm);
1586 debug!("emit_suggestion_default: suggestions={:?}", suggestions);
1588 if suggestions.is_empty() {
1589 // Suggestions coming from macros can have malformed spans. This is a heavy handed
1590 // approach to avoid ICEs by ignoring the suggestion outright.
1594 let mut buffer = StyledBuffer::new();
1596 // Render the suggestion message
1597 buffer.append(0, level.to_str(), Style::Level(*level));
1598 buffer.append(0, ": ", Style::HeaderMsg);
1602 &[(suggestion.msg.to_owned(), Style::NoStyle)],
1605 Some(Style::HeaderMsg),
1608 let mut row_num = 2;
1609 draw_col_separator_no_space(&mut buffer, 1, max_line_num_len + 1);
1610 let mut notice_capitalization = false;
1611 for (complete, parts, highlights, only_capitalization) in
1612 suggestions.iter().take(MAX_SUGGESTIONS)
1614 notice_capitalization |= only_capitalization;
1615 // Only show underline if the suggestion spans a single line and doesn't cover the
1616 // entirety of the code output. If you have multiple replacements in the same line
1617 // of code, show the underline.
1618 let show_underline = !(parts.len() == 1 && parts[0].snippet.trim() == complete.trim())
1619 && complete.lines().count() == 1;
1621 let has_deletion = parts.iter().any(|p| p.is_deletion());
1622 let is_multiline = complete.lines().count() > 1;
1624 let show_diff = has_deletion && !is_multiline;
1631 .span_to_lines(parts[0].span)
1632 .expect("span_to_lines failed when emitting suggestion");
1634 assert!(!file_lines.lines.is_empty() || parts[0].span.is_dummy());
1636 let line_start = sm.lookup_char_pos(parts[0].span.lo()).line;
1637 draw_col_separator_no_space(&mut buffer, 1, max_line_num_len + 1);
1638 let mut lines = complete.lines();
1639 for (line_pos, (line, highlight_parts)) in
1640 lines.by_ref().zip(highlights).take(MAX_SUGGESTION_HIGHLIGHT_LINES).enumerate()
1642 // Print the span column to avoid confusion
1646 &self.maybe_anonymized(line_start + line_pos),
1650 // Add the line number for both addition and removal to drive the point home.
1652 // N - fn foo<A: T>(bar: A) {
1653 // N + fn foo(bar: impl T) {
1657 &self.maybe_anonymized(line_start + line_pos),
1660 buffer.puts(row_num - 1, max_line_num_len + 1, "- ", Style::Removal);
1663 max_line_num_len + 3,
1667 .get_line(file_lines.lines[line_pos].line_index)
1672 buffer.puts(row_num, max_line_num_len + 1, "+ ", Style::Addition);
1673 } else if is_multiline {
1674 match &highlight_parts[..] {
1675 [SubstitutionHighlight { start: 0, end }] if *end == line.len() => {
1676 buffer.puts(row_num, max_line_num_len + 1, "+ ", Style::Addition);
1679 draw_col_separator(&mut buffer, row_num, max_line_num_len + 1);
1682 buffer.puts(row_num, max_line_num_len + 1, "~ ", Style::Addition);
1686 draw_col_separator(&mut buffer, row_num, max_line_num_len + 1);
1689 // print the suggestion
1690 buffer.append(row_num, &replace_tabs(line), Style::NoStyle);
1692 // Colorize addition/replacements with green.
1693 for &SubstitutionHighlight { start, end } in highlight_parts {
1694 // Account for tabs when highlighting (#87972).
1695 let tabs: usize = line
1698 .map(|ch| match ch {
1703 buffer.set_style_range(
1705 max_line_num_len + 3 + start + tabs,
1706 max_line_num_len + 3 + end + tabs,
1714 // This offset and the ones below need to be signed to account for replacement code
1715 // that is shorter than the original code.
1716 let mut offsets: Vec<(usize, isize)> = Vec::new();
1717 // Only show an underline in the suggestions if the suggestion is not the
1718 // entirety of the code being shown and the displayed code is not multiline.
1720 draw_col_separator(&mut buffer, row_num, max_line_num_len + 1);
1722 let span_start_pos = sm.lookup_char_pos(part.span.lo()).col_display;
1723 let span_end_pos = sm.lookup_char_pos(part.span.hi()).col_display;
1725 // Do not underline the leading...
1726 let start = part.snippet.len().saturating_sub(part.snippet.trim_start().len());
1727 // ...or trailing spaces. Account for substitutions containing unicode
1729 let sub_len: usize = part
1733 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
1736 let offset: isize = offsets
1739 |(start, v)| if span_start_pos <= *start { None } else { Some(v) },
1742 let underline_start = (span_start_pos + start) as isize + offset;
1743 let underline_end = (span_start_pos + start + sub_len) as isize + offset;
1744 assert!(underline_start >= 0 && underline_end >= 0);
1745 let padding: usize = max_line_num_len + 3;
1746 for p in underline_start..underline_end {
1748 // If this is a replacement, underline with `^`, if this is an addition
1749 // underline with `+`.
1752 (padding as isize + p) as usize,
1753 if part.is_addition(&sm) { '+' } else { '~' },
1759 // Colorize removal with red in diff format.
1760 buffer.set_style_range(
1762 (padding as isize + span_start_pos as isize) as usize,
1763 (padding as isize + span_end_pos as isize) as usize,
1769 // length of the code after substitution
1770 let full_sub_len = part
1773 .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
1774 .sum::<usize>() as isize;
1776 // length of the code to be substituted
1777 let snippet_len = span_end_pos as isize - span_start_pos as isize;
1778 // For multiple substitutions, use the position *after* the previous
1779 // substitutions have happened, only when further substitutions are
1780 // located strictly after.
1781 offsets.push((span_end_pos, full_sub_len - snippet_len));
1786 // if we elided some lines, add an ellipsis
1787 if lines.next().is_some() {
1788 buffer.puts(row_num, max_line_num_len - 1, "...", Style::LineNumber);
1789 } else if !show_underline {
1790 draw_col_separator_no_space(&mut buffer, row_num, max_line_num_len + 1);
1794 if suggestions.len() > MAX_SUGGESTIONS {
1795 let others = suggestions.len() - MAX_SUGGESTIONS;
1796 let msg = format!("and {} other candidate{}", others, pluralize!(others));
1797 buffer.puts(row_num, max_line_num_len + 3, &msg, Style::NoStyle);
1798 } else if notice_capitalization {
1799 let msg = "notice the capitalization difference";
1800 buffer.puts(row_num, max_line_num_len + 3, &msg, Style::NoStyle);
1802 emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
1806 fn emit_messages_default(
1809 message: &[(String, Style)],
1810 code: &Option<DiagnosticId>,
1812 children: &[SubDiagnostic],
1813 suggestions: &[CodeSuggestion],
1815 let max_line_num_len = if self.ui_testing {
1816 ANONYMIZED_LINE_NUM.len()
1818 let n = self.get_max_line_num(span, children);
1819 num_decimal_digits(n)
1822 match self.emit_message_default(span, message, code, level, max_line_num_len, false) {
1824 if !children.is_empty()
1825 || suggestions.iter().any(|s| s.style != SuggestionStyle::CompletelyHidden)
1827 let mut buffer = StyledBuffer::new();
1828 if !self.short_message {
1829 draw_col_separator_no_space(&mut buffer, 0, max_line_num_len + 1);
1831 if let Err(e) = emit_to_destination(
1837 panic!("failed to emit error: {}", e)
1840 if !self.short_message {
1841 for child in children {
1842 let span = child.render_span.as_ref().unwrap_or(&child.span);
1843 if let Err(err) = self.emit_message_default(
1845 &child.styled_message(),
1851 panic!("failed to emit error: {}", err);
1854 for sugg in suggestions {
1855 if sugg.style == SuggestionStyle::CompletelyHidden {
1856 // do not display this suggestion, it is meant only for tools
1857 } else if sugg.style == SuggestionStyle::HideCodeAlways {
1858 if let Err(e) = self.emit_message_default(
1860 &[(sugg.msg.to_owned(), Style::HeaderMsg)],
1866 panic!("failed to emit error: {}", e);
1868 } else if let Err(e) =
1869 self.emit_suggestion_default(sugg, &Level::Help, max_line_num_len)
1871 panic!("failed to emit error: {}", e);
1876 Err(e) => panic!("failed to emit error: {}", e),
1879 let mut dst = self.dst.writable();
1880 match writeln!(dst) {
1881 Err(e) => panic!("failed to emit error: {}", e),
1883 if let Err(e) = dst.flush() {
1884 panic!("failed to emit error: {}", e)
1891 impl FileWithAnnotatedLines {
1892 /// Preprocess all the annotations so that they are grouped by file and by line number
1893 /// This helps us quickly iterate over the whole message (including secondary file spans)
1894 pub fn collect_annotations(
1896 source_map: &Option<Lrc<SourceMap>>,
1897 ) -> Vec<FileWithAnnotatedLines> {
1898 fn add_annotation_to_file(
1899 file_vec: &mut Vec<FileWithAnnotatedLines>,
1900 file: Lrc<SourceFile>,
1904 for slot in file_vec.iter_mut() {
1905 // Look through each of our files for the one we're adding to
1906 if slot.file.name == file.name {
1907 // See if we already have a line for it
1908 for line_slot in &mut slot.lines {
1909 if line_slot.line_index == line_index {
1910 line_slot.annotations.push(ann);
1914 // We don't have a line yet, create one
1915 slot.lines.push(Line { line_index, annotations: vec![ann] });
1920 // This is the first time we're seeing the file
1921 file_vec.push(FileWithAnnotatedLines {
1923 lines: vec![Line { line_index, annotations: vec![ann] }],
1928 let mut output = vec![];
1929 let mut multiline_annotations = vec![];
1931 if let Some(ref sm) = source_map {
1932 for span_label in msp.span_labels() {
1933 if span_label.span.is_dummy() {
1937 let lo = sm.lookup_char_pos(span_label.span.lo());
1938 let mut hi = sm.lookup_char_pos(span_label.span.hi());
1940 // Watch out for "empty spans". If we get a span like 6..6, we
1941 // want to just display a `^` at 6, so convert that to
1942 // 6..7. This is degenerate input, but it's best to degrade
1943 // gracefully -- and the parser likes to supply a span like
1944 // that for EOF, in particular.
1946 if lo.col_display == hi.col_display && lo.line == hi.line {
1947 hi.col_display += 1;
1950 if lo.line != hi.line {
1951 let ml = MultilineAnnotation {
1953 line_start: lo.line,
1955 start_col: lo.col_display,
1956 end_col: hi.col_display,
1957 is_primary: span_label.is_primary,
1958 label: span_label.label,
1959 overlaps_exactly: false,
1961 multiline_annotations.push((lo.file, ml));
1963 let ann = Annotation {
1964 start_col: lo.col_display,
1965 end_col: hi.col_display,
1966 is_primary: span_label.is_primary,
1967 label: span_label.label,
1968 annotation_type: AnnotationType::Singleline,
1970 add_annotation_to_file(&mut output, lo.file, lo.line, ann);
1975 // Find overlapping multiline annotations, put them at different depths
1976 multiline_annotations.sort_by_key(|&(_, ref ml)| (ml.line_start, ml.line_end));
1977 for (_, ann) in multiline_annotations.clone() {
1978 for (_, a) in multiline_annotations.iter_mut() {
1979 // Move all other multiline annotations overlapping with this one
1980 // one level to the right.
1981 if !(ann.same_span(a))
1982 && num_overlap(ann.line_start, ann.line_end, a.line_start, a.line_end, true)
1985 } else if ann.same_span(a) && &ann != a {
1986 a.overlaps_exactly = true;
1993 let mut max_depth = 0; // max overlapping multiline spans
1994 for (file, ann) in multiline_annotations {
1995 max_depth = max(max_depth, ann.depth);
1996 let mut end_ann = ann.as_end();
1997 if !ann.overlaps_exactly {
1998 // avoid output like
2020 add_annotation_to_file(&mut output, file.clone(), ann.line_start, ann.as_start());
2021 // 4 is the minimum vertical length of a multiline span when presented: two lines
2022 // of code and two lines of underline. This is not true for the special case where
2023 // the beginning doesn't have an underline, but the current logic seems to be
2024 // working correctly.
2025 let middle = min(ann.line_start + 4, ann.line_end);
2026 for line in ann.line_start + 1..middle {
2027 // Every `|` that joins the beginning of the span (`___^`) to the end (`|__^`).
2028 add_annotation_to_file(&mut output, file.clone(), line, ann.as_line());
2030 let line_end = ann.line_end - 1;
2031 if middle < line_end {
2032 add_annotation_to_file(&mut output, file.clone(), line_end, ann.as_line());
2035 end_ann.annotation_type = AnnotationType::Singleline;
2037 add_annotation_to_file(&mut output, file, ann.line_end, end_ann);
2039 for file_vec in output.iter_mut() {
2040 file_vec.multiline_depth = max_depth;
2046 // instead of taking the String length or dividing by 10 while > 0, we multiply a limit by 10 until
2047 // we're higher. If the loop isn't exited by the `return`, the last multiplication will wrap, which
2048 // is OK, because while we cannot fit a higher power of 10 in a usize, the loop will end anyway.
2049 // This is also why we need the max number of decimal digits within a `usize`.
2050 fn num_decimal_digits(num: usize) -> usize {
2051 #[cfg(target_pointer_width = "64")]
2052 const MAX_DIGITS: usize = 20;
2054 #[cfg(target_pointer_width = "32")]
2055 const MAX_DIGITS: usize = 10;
2057 #[cfg(target_pointer_width = "16")]
2058 const MAX_DIGITS: usize = 5;
2061 for num_digits in 1..MAX_DIGITS {
2065 lim = lim.wrapping_mul(10);
2070 fn replace_tabs(str: &str) -> String {
2071 str.replace('\t', " ")
2074 fn draw_col_separator(buffer: &mut StyledBuffer, line: usize, col: usize) {
2075 buffer.puts(line, col, "| ", Style::LineNumber);
2078 fn draw_col_separator_no_space(buffer: &mut StyledBuffer, line: usize, col: usize) {
2079 draw_col_separator_no_space_with_style(buffer, line, col, Style::LineNumber);
2082 fn draw_col_separator_no_space_with_style(
2083 buffer: &mut StyledBuffer,
2088 buffer.putc(line, col, '|', style);
2092 buffer: &mut StyledBuffer,
2099 for col in col_from..col_to {
2100 buffer.putc(line, col, symbol, style);
2104 fn draw_note_separator(buffer: &mut StyledBuffer, line: usize, col: usize) {
2105 buffer.puts(line, col, "= ", Style::LineNumber);
2108 fn draw_multiline_line(
2109 buffer: &mut StyledBuffer,
2115 buffer.putc(line, offset + depth - 1, '|', style);
2125 let extra = if inclusive { 1 } else { 0 };
2126 (b_start..b_end + extra).contains(&a_start) || (a_start..a_end + extra).contains(&b_start)
2128 fn overlaps(a1: &Annotation, a2: &Annotation, padding: usize) -> bool {
2129 num_overlap(a1.start_col, a1.end_col + padding, a2.start_col, a2.end_col, false)
2132 fn emit_to_destination(
2133 rendered_buffer: &[Vec<StyledString>],
2135 dst: &mut Destination,
2136 short_message: bool,
2137 ) -> io::Result<()> {
2140 let mut dst = dst.writable();
2142 // In order to prevent error message interleaving, where multiple error lines get intermixed
2143 // when multiple compiler processes error simultaneously, we emit errors with additional
2146 // On Unix systems, we write into a buffered terminal rather than directly to a terminal. When
2147 // the .flush() is called we take the buffer created from the buffered writes and write it at
2148 // one shot. Because the Unix systems use ANSI for the colors, which is a text-based styling
2149 // scheme, this buffered approach works and maintains the styling.
2151 // On Windows, styling happens through calls to a terminal API. This prevents us from using the
2152 // same buffering approach. Instead, we use a global Windows mutex, which we acquire long
2153 // enough to output the full error message, then we release.
2154 let _buffer_lock = lock::acquire_global_lock("rustc_errors");
2155 for (pos, line) in rendered_buffer.iter().enumerate() {
2157 dst.apply_style(*lvl, part.style)?;
2158 write!(dst, "{}", part.text)?;
2161 if !short_message && (!lvl.is_failure_note() || pos != rendered_buffer.len() - 1) {
2169 pub enum Destination {
2170 Terminal(StandardStream),
2171 Buffered(BufferWriter),
2172 // The bool denotes whether we should be emitting ansi color codes or not
2173 Raw(Box<(dyn Write + Send)>, bool),
2176 pub enum WritableDst<'a> {
2177 Terminal(&'a mut StandardStream),
2178 Buffered(&'a mut BufferWriter, Buffer),
2179 Raw(&'a mut (dyn Write + Send)),
2180 ColoredRaw(Ansi<&'a mut (dyn Write + Send)>),
2184 fn from_stderr(color: ColorConfig) -> Destination {
2185 let choice = color.to_color_choice();
2186 // On Windows we'll be performing global synchronization on the entire
2187 // system for emitting rustc errors, so there's no need to buffer
2190 // On non-Windows we rely on the atomicity of `write` to ensure errors
2191 // don't get all jumbled up.
2193 Terminal(StandardStream::stderr(choice))
2195 Buffered(BufferWriter::stderr(choice))
2199 fn writable(&mut self) -> WritableDst<'_> {
2201 Destination::Terminal(ref mut t) => WritableDst::Terminal(t),
2202 Destination::Buffered(ref mut t) => {
2203 let buf = t.buffer();
2204 WritableDst::Buffered(t, buf)
2206 Destination::Raw(ref mut t, false) => WritableDst::Raw(t),
2207 Destination::Raw(ref mut t, true) => WritableDst::ColoredRaw(Ansi::new(t)),
2211 fn supports_color(&self) -> bool {
2213 Self::Terminal(ref stream) => stream.supports_color(),
2214 Self::Buffered(ref buffer) => buffer.buffer().supports_color(),
2215 Self::Raw(_, supports_color) => supports_color,
2220 impl<'a> WritableDst<'a> {
2221 fn apply_style(&mut self, lvl: Level, style: Style) -> io::Result<()> {
2222 let mut spec = ColorSpec::new();
2224 Style::Addition => {
2225 spec.set_fg(Some(Color::Green)).set_intense(true);
2228 spec.set_fg(Some(Color::Red)).set_intense(true);
2230 Style::LineAndColumn => {}
2231 Style::LineNumber => {
2232 spec.set_bold(true);
2233 spec.set_intense(true);
2235 spec.set_fg(Some(Color::Cyan));
2237 spec.set_fg(Some(Color::Blue));
2240 Style::Quotation => {}
2241 Style::MainHeaderMsg => {
2242 spec.set_bold(true);
2244 spec.set_intense(true).set_fg(Some(Color::White));
2247 Style::UnderlinePrimary | Style::LabelPrimary => {
2249 spec.set_bold(true);
2251 Style::UnderlineSecondary | Style::LabelSecondary => {
2252 spec.set_bold(true).set_intense(true);
2254 spec.set_fg(Some(Color::Cyan));
2256 spec.set_fg(Some(Color::Blue));
2259 Style::HeaderMsg | Style::NoStyle => {}
2260 Style::Level(lvl) => {
2262 spec.set_bold(true);
2264 Style::Highlight => {
2265 spec.set_bold(true);
2268 self.set_color(&spec)
2271 fn set_color(&mut self, color: &ColorSpec) -> io::Result<()> {
2273 WritableDst::Terminal(ref mut t) => t.set_color(color),
2274 WritableDst::Buffered(_, ref mut t) => t.set_color(color),
2275 WritableDst::ColoredRaw(ref mut t) => t.set_color(color),
2276 WritableDst::Raw(_) => Ok(()),
2280 fn reset(&mut self) -> io::Result<()> {
2282 WritableDst::Terminal(ref mut t) => t.reset(),
2283 WritableDst::Buffered(_, ref mut t) => t.reset(),
2284 WritableDst::ColoredRaw(ref mut t) => t.reset(),
2285 WritableDst::Raw(_) => Ok(()),
2290 impl<'a> Write for WritableDst<'a> {
2291 fn write(&mut self, bytes: &[u8]) -> io::Result<usize> {
2293 WritableDst::Terminal(ref mut t) => t.write(bytes),
2294 WritableDst::Buffered(_, ref mut buf) => buf.write(bytes),
2295 WritableDst::Raw(ref mut w) => w.write(bytes),
2296 WritableDst::ColoredRaw(ref mut t) => t.write(bytes),
2300 fn flush(&mut self) -> io::Result<()> {
2302 WritableDst::Terminal(ref mut t) => t.flush(),
2303 WritableDst::Buffered(_, ref mut buf) => buf.flush(),
2304 WritableDst::Raw(ref mut w) => w.flush(),
2305 WritableDst::ColoredRaw(ref mut w) => w.flush(),
2310 impl<'a> Drop for WritableDst<'a> {
2311 fn drop(&mut self) {
2312 if let WritableDst::Buffered(ref mut dst, ref mut buf) = self {
2313 drop(dst.print(buf));
2318 /// Whether the original and suggested code are visually similar enough to warrant extra wording.
2319 pub fn is_case_difference(sm: &SourceMap, suggested: &str, sp: Span) -> bool {
2320 // FIXME: this should probably be extended to also account for `FO0` → `FOO` and unicode.
2321 let found = match sm.span_to_snippet(sp) {
2322 Ok(snippet) => snippet,
2324 warn!("Invalid span {:?}. Err={:?}", sp, e);
2328 let ascii_confusables = &['c', 'f', 'i', 'k', 'o', 's', 'u', 'v', 'w', 'x', 'y', 'z'];
2329 // All the chars that differ in capitalization are confusable (above):
2330 let confusable = iter::zip(found.chars(), suggested.chars())
2331 .filter(|(f, s)| f != s)
2332 .all(|(f, s)| (ascii_confusables.contains(&f) || ascii_confusables.contains(&s)));
2333 confusable && found.to_lowercase() == suggested.to_lowercase()
2334 // FIXME: We sometimes suggest the same thing we already have, which is a
2335 // bug, but be defensive against that here.
2336 && found != suggested