1 use crate::{Diagnostic, DiagnosticId, DiagnosticStyledString};
2 use crate::{Handler, Level, StashKey};
3 use rustc_lint_defs::Applicability;
5 use rustc_span::{MultiSpan, Span};
6 use std::fmt::{self, Debug};
7 use std::ops::{Deref, DerefMut};
8 use std::thread::panicking;
11 /// Used for emitting structured error messages and other diagnostic information.
13 /// If there is some state in a downstream crate you would like to
14 /// access in the methods of `DiagnosticBuilder` here, consider
15 /// extending `HandlerFlags`, accessed via `self.handler.flags`.
18 pub struct DiagnosticBuilder<'a>(Box<DiagnosticBuilderInner<'a>>);
20 /// This is a large type, and often used as a return value, especially within
21 /// the frequently-used `PResult` type. In theory, return value optimization
22 /// (RVO) should avoid unnecessary copying. In practice, it does not (at the
23 /// time of writing). The split between `DiagnosticBuilder` and
24 /// `DiagnosticBuilderInner` exists to avoid many `memcpy` calls.
27 struct DiagnosticBuilderInner<'a> {
29 diagnostic: Diagnostic,
30 allow_suggestions: bool,
33 /// This is a helper macro for [`forward!`] that allows automatically adding documentation
34 /// that uses tokens from [`forward!`]'s input.
35 macro_rules! forward_inner_docs {
36 ($e:expr => $i:item) => {
42 /// In general, the `DiagnosticBuilder` uses deref to allow access to
43 /// the fields and methods of the embedded `diagnostic` in a
44 /// transparent way. *However,* many of the methods are intended to
45 /// be used in a chained way, and hence ought to return `self`. In
46 /// that case, we can't just naively forward to the method on the
47 /// `diagnostic`, because the return type would be a `&Diagnostic`
48 /// instead of a `&DiagnosticBuilder<'a>`. This `forward!` macro makes
49 /// it easy to declare such methods on the builder.
50 macro_rules! forward {
51 // Forward pattern for &self -> &Self
54 pub fn $n:ident(&self, $($name:ident: $ty:ty),* $(,)?) -> &Self
57 forward_inner_docs!(concat!("See [`Diagnostic::", stringify!($n), "()`].") =>
58 pub fn $n(&self, $($name: $ty),*) -> &Self {
59 self.diagnostic.$n($($name),*);
64 // Forward pattern for &mut self -> &mut Self
67 pub fn $n:ident(&mut self, $($name:ident: $ty:ty),* $(,)?) -> &mut Self
70 forward_inner_docs!(concat!("See [`Diagnostic::", stringify!($n), "()`].") =>
71 pub fn $n(&mut self, $($name: $ty),*) -> &mut Self {
72 self.0.diagnostic.$n($($name),*);
77 // Forward pattern for &mut self -> &mut Self, with generic parameters.
80 pub fn $n:ident<$($generic:ident: $bound:path),*>(
82 $($name:ident: $ty:ty),*
87 forward_inner_docs!(concat!("See [`Diagnostic::", stringify!($n), "()`].") =>
88 pub fn $n<$($generic: $bound),*>(&mut self, $($name: $ty),*) -> &mut Self {
89 self.0.diagnostic.$n($($name),*);
95 impl<'a> Deref for DiagnosticBuilder<'a> {
96 type Target = Diagnostic;
98 fn deref(&self) -> &Diagnostic {
103 impl<'a> DerefMut for DiagnosticBuilder<'a> {
104 fn deref_mut(&mut self) -> &mut Diagnostic {
105 &mut self.0.diagnostic
109 impl<'a> DiagnosticBuilder<'a> {
110 /// Emit the diagnostic.
111 pub fn emit(&mut self) {
112 self.0.handler.emit_diagnostic(&self);
116 /// Emit the diagnostic unless `delay` is true,
117 /// in which case the emission will be delayed as a bug.
119 /// See `emit` and `delay_as_bug` for details.
120 pub fn emit_unless(&mut self, delay: bool) {
128 /// Stashes diagnostic for possible later improvement in a different,
129 /// later stage of the compiler. The diagnostic can be accessed with
130 /// the provided `span` and `key` through [`Handler::steal_diagnostic()`].
132 /// As with `buffer`, this is unless the handler has disabled such buffering.
133 pub fn stash(self, span: Span, key: StashKey) {
134 if let Some((diag, handler)) = self.into_diagnostic() {
135 handler.stash_diagnostic(span, key, diag);
139 /// Converts the builder to a `Diagnostic` for later emission,
140 /// unless handler has disabled such buffering.
141 pub fn into_diagnostic(mut self) -> Option<(Diagnostic, &'a Handler)> {
142 if self.0.handler.flags.dont_buffer_diagnostics
143 || self.0.handler.flags.treat_err_as_bug.is_some()
149 let handler = self.0.handler;
151 // We must use `Level::Cancelled` for `dummy` to avoid an ICE about an
152 // unused diagnostic.
153 let dummy = Diagnostic::new(Level::Cancelled, "");
154 let diagnostic = std::mem::replace(&mut self.0.diagnostic, dummy);
156 // Logging here is useful to help track down where in logs an error was
158 debug!("buffer: diagnostic={:?}", diagnostic);
160 Some((diagnostic, handler))
163 /// Buffers the diagnostic for later emission,
164 /// unless handler has disabled such buffering.
165 pub fn buffer(self, buffered_diagnostics: &mut Vec<Diagnostic>) {
166 buffered_diagnostics.extend(self.into_diagnostic().map(|(diag, _)| diag));
169 /// Convenience function for internal use, clients should use one of the
170 /// span_* methods instead.
171 pub fn sub<S: Into<MultiSpan>>(
177 let span = span.map(|s| s.into()).unwrap_or_else(MultiSpan::new);
178 self.0.diagnostic.sub(level, message, span, None);
182 /// Delay emission of this diagnostic as a bug.
184 /// This can be useful in contexts where an error indicates a bug but
185 /// typically this only happens when other compilation errors have already
186 /// happened. In those cases this can be used to defer emission of this
187 /// diagnostic as a bug in the compiler only if no other errors have been
190 /// In the meantime, though, callsites are required to deal with the "bug"
191 /// locally in whichever way makes the most sense.
192 pub fn delay_as_bug(&mut self) {
193 self.level = Level::Bug;
194 self.0.handler.delay_as_bug(self.0.diagnostic.clone());
198 /// Appends a labeled span to the diagnostic.
200 /// Labels are used to convey additional context for the diagnostic's primary span. They will
201 /// be shown together with the original diagnostic's span, *not* with spans added by
202 /// `span_note`, `span_help`, etc. Therefore, if the primary span is not displayable (because
203 /// the span is `DUMMY_SP` or the source code isn't found), labels will not be displayed
206 /// Implementation-wise, the label span is pushed onto the [`MultiSpan`] that was created when
207 /// the diagnostic was constructed. However, the label span is *not* considered a
208 /// ["primary span"][`MultiSpan`]; only the `Span` supplied when creating the diagnostic is
210 pub fn span_label(&mut self, span: Span, label: impl Into<String>) -> &mut Self {
211 self.0.diagnostic.span_label(span, label);
215 /// Labels all the given spans with the provided label.
216 /// See [`Diagnostic::span_label()`] for more information.
219 spans: impl IntoIterator<Item = Span>,
220 label: impl AsRef<str>,
222 let label = label.as_ref();
224 self.0.diagnostic.span_label(span, label);
229 forward!(pub fn note_expected_found(
231 expected_label: &dyn fmt::Display,
232 expected: DiagnosticStyledString,
233 found_label: &dyn fmt::Display,
234 found: DiagnosticStyledString,
237 forward!(pub fn note_expected_found_extra(
239 expected_label: &dyn fmt::Display,
240 expected: DiagnosticStyledString,
241 found_label: &dyn fmt::Display,
242 found: DiagnosticStyledString,
243 expected_extra: &dyn fmt::Display,
244 found_extra: &dyn fmt::Display,
247 forward!(pub fn note_unsuccessful_coercion(
249 expected: DiagnosticStyledString,
250 found: DiagnosticStyledString,
253 forward!(pub fn note(&mut self, msg: &str) -> &mut Self);
254 forward!(pub fn span_note<S: Into<MultiSpan>>(
259 forward!(pub fn warn(&mut self, msg: &str) -> &mut Self);
260 forward!(pub fn span_warn<S: Into<MultiSpan>>(&mut self, sp: S, msg: &str) -> &mut Self);
261 forward!(pub fn help(&mut self, msg: &str) -> &mut Self);
262 forward!(pub fn span_help<S: Into<MultiSpan>>(
268 /// See [`Diagnostic::multipart_suggestion()`].
269 pub fn multipart_suggestion(
272 suggestion: Vec<(Span, String)>,
273 applicability: Applicability,
275 if !self.0.allow_suggestions {
278 self.0.diagnostic.multipart_suggestion(msg, suggestion, applicability);
282 /// See [`Diagnostic::multipart_suggestions()`].
283 pub fn multipart_suggestions(
286 suggestions: Vec<Vec<(Span, String)>>,
287 applicability: Applicability,
289 if !self.0.allow_suggestions {
292 self.0.diagnostic.multipart_suggestions(msg, suggestions, applicability);
296 /// See [`Diagnostic::tool_only_multipart_suggestion()`].
297 pub fn tool_only_multipart_suggestion(
300 suggestion: Vec<(Span, String)>,
301 applicability: Applicability,
303 if !self.0.allow_suggestions {
306 self.0.diagnostic.tool_only_multipart_suggestion(msg, suggestion, applicability);
310 /// See [`Diagnostic::span_suggestion()`].
311 pub fn span_suggestion(
316 applicability: Applicability,
318 if !self.0.allow_suggestions {
321 self.0.diagnostic.span_suggestion(sp, msg, suggestion, applicability);
325 /// See [`Diagnostic::span_suggestions()`].
326 pub fn span_suggestions(
330 suggestions: impl Iterator<Item = String>,
331 applicability: Applicability,
333 if !self.0.allow_suggestions {
336 self.0.diagnostic.span_suggestions(sp, msg, suggestions, applicability);
340 /// See [`Diagnostic::span_suggestion_short()`].
341 pub fn span_suggestion_short(
346 applicability: Applicability,
348 if !self.0.allow_suggestions {
351 self.0.diagnostic.span_suggestion_short(sp, msg, suggestion, applicability);
355 /// See [`Diagnostic::span_suggestion_verbose()`].
356 pub fn span_suggestion_verbose(
361 applicability: Applicability,
363 if !self.0.allow_suggestions {
366 self.0.diagnostic.span_suggestion_verbose(sp, msg, suggestion, applicability);
370 /// See [`Diagnostic::span_suggestion_hidden()`].
371 pub fn span_suggestion_hidden(
376 applicability: Applicability,
378 if !self.0.allow_suggestions {
381 self.0.diagnostic.span_suggestion_hidden(sp, msg, suggestion, applicability);
385 /// See [`Diagnostic::tool_only_span_suggestion()`] for more information.
386 pub fn tool_only_span_suggestion(
391 applicability: Applicability,
393 if !self.0.allow_suggestions {
396 self.0.diagnostic.tool_only_span_suggestion(sp, msg, suggestion, applicability);
400 forward!(pub fn set_primary_message<M: Into<String>>(&mut self, msg: M) -> &mut Self);
401 forward!(pub fn set_span<S: Into<MultiSpan>>(&mut self, sp: S) -> &mut Self);
402 forward!(pub fn code(&mut self, s: DiagnosticId) -> &mut Self);
404 /// Allow attaching suggestions this diagnostic.
405 /// If this is set to `false`, then any suggestions attached with the `span_suggestion_*`
406 /// methods after this is set to `false` will be ignored.
407 pub fn allow_suggestions(&mut self, allow: bool) -> &mut Self {
408 self.0.allow_suggestions = allow;
412 /// Convenience function for internal use, clients should use one of the
413 /// `struct_*` methods on [`Handler`].
414 crate fn new(handler: &'a Handler, level: Level, message: &str) -> DiagnosticBuilder<'a> {
415 DiagnosticBuilder::new_with_code(handler, level, None, message)
418 /// Convenience function for internal use, clients should use one of the
419 /// `struct_*` methods on [`Handler`].
420 crate fn new_with_code(
421 handler: &'a Handler,
423 code: Option<DiagnosticId>,
425 ) -> DiagnosticBuilder<'a> {
426 let diagnostic = Diagnostic::new_with_code(level, code, message);
427 DiagnosticBuilder::new_diagnostic(handler, diagnostic)
430 /// Creates a new `DiagnosticBuilder` with an already constructed
432 crate fn new_diagnostic(handler: &'a Handler, diagnostic: Diagnostic) -> DiagnosticBuilder<'a> {
433 debug!("Created new diagnostic");
434 DiagnosticBuilder(Box::new(DiagnosticBuilderInner {
437 allow_suggestions: true,
442 impl<'a> Debug for DiagnosticBuilder<'a> {
443 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
444 self.0.diagnostic.fmt(f)
448 /// Destructor bomb - a `DiagnosticBuilder` must be either emitted or canceled
449 /// or we emit a bug.
450 impl<'a> Drop for DiagnosticBuilder<'a> {
452 if !panicking() && !self.cancelled() {
453 let mut db = DiagnosticBuilder::new(
456 "the following error was constructed but not emitted",
466 macro_rules! struct_span_err {
467 ($session:expr, $span:expr, $code:ident, $($message:tt)*) => ({
468 $session.struct_span_err_with_code(
470 &format!($($message)*),
471 $crate::error_code!($code),
477 macro_rules! error_code {
478 ($code:ident) => {{ $crate::DiagnosticId::Error(stringify!($code).to_owned()) }};