2 use crate::DiagnosticId;
3 use crate::DiagnosticStyledString;
4 use crate::Applicability;
8 use std::fmt::{self, Debug};
9 use std::ops::{Deref, DerefMut};
10 use std::thread::panicking;
11 use syntax_pos::{MultiSpan, Span};
14 /// Used for emitting structured error messages and other diagnostic information.
16 /// If there is some state in a downstream crate you would like to
17 /// access in the methods of `DiagnosticBuilder` here, consider
18 /// extending `HandlerFlags`, accessed via `self.handler.flags`.
21 pub struct DiagnosticBuilder<'a> {
22 pub handler: &'a Handler,
23 diagnostic: Diagnostic,
24 allow_suggestions: bool,
27 /// In general, the `DiagnosticBuilder` uses deref to allow access to
28 /// the fields and methods of the embedded `diagnostic` in a
29 /// transparent way. *However,* many of the methods are intended to
30 /// be used in a chained way, and hence ought to return `self`. In
31 /// that case, we can't just naively forward to the method on the
32 /// `diagnostic`, because the return type would be a `&Diagnostic`
33 /// instead of a `&DiagnosticBuilder<'a>`. This `forward!` macro makes
34 /// it easy to declare such methods on the builder.
35 macro_rules! forward {
36 // Forward pattern for &self -> &Self
39 pub fn $n:ident(&self, $($name:ident: $ty:ty),* $(,)*) -> &Self
42 pub fn $n(&self, $($name: $ty),*) -> &Self {
43 self.diagnostic.$n($($name),*);
48 // Forward pattern for &mut self -> &mut Self
51 pub fn $n:ident(&mut self, $($name:ident: $ty:ty),* $(,)*) -> &mut Self
54 pub fn $n(&mut self, $($name: $ty),*) -> &mut Self {
55 self.diagnostic.$n($($name),*);
60 // Forward pattern for &mut self -> &mut Self, with S: Into<MultiSpan>
61 // type parameter. No obvious way to make this more generic.
64 pub fn $n:ident<S: Into<MultiSpan>>(
66 $($name:ident: $ty:ty),*
71 pub fn $n<S: Into<MultiSpan>>(&mut self, $($name: $ty),*) -> &mut Self {
72 self.diagnostic.$n($($name),*);
78 impl<'a> Deref for DiagnosticBuilder<'a> {
79 type Target = Diagnostic;
81 fn deref(&self) -> &Diagnostic {
86 impl<'a> DerefMut for DiagnosticBuilder<'a> {
87 fn deref_mut(&mut self) -> &mut Diagnostic {
92 impl<'a> DiagnosticBuilder<'a> {
93 /// Emit the diagnostic.
94 pub fn emit(&mut self) {
99 self.handler.emit_db(&self);
103 /// Buffers the diagnostic for later emission, unless handler
104 /// has disabled such buffering.
105 pub fn buffer(mut self, buffered_diagnostics: &mut Vec<Diagnostic>) {
106 if self.handler.flags.dont_buffer_diagnostics || self.handler.flags.treat_err_as_bug {
111 // We need to use `ptr::read` because `DiagnosticBuilder`
112 // implements `Drop`.
115 diagnostic = std::ptr::read(&self.diagnostic);
116 std::mem::forget(self);
118 // Logging here is useful to help track down where in logs an error was
120 debug!("buffer: diagnostic={:?}", diagnostic);
121 buffered_diagnostics.push(diagnostic);
124 /// Convenience function for internal use, clients should use one of the
125 /// span_* methods instead.
126 pub fn sub<S: Into<MultiSpan>>(
132 let span = span.map(|s| s.into()).unwrap_or_else(|| MultiSpan::new());
133 self.diagnostic.sub(level, message, span, None);
137 /// Delay emission of this diagnostic as a bug.
139 /// This can be useful in contexts where an error indicates a bug but
140 /// typically this only happens when other compilation errors have already
141 /// happened. In those cases this can be used to defer emission of this
142 /// diagnostic as a bug in the compiler only if no other errors have been
145 /// In the meantime, though, callsites are required to deal with the "bug"
146 /// locally in whichever way makes the most sense.
147 pub fn delay_as_bug(&mut self) {
148 self.level = Level::Bug;
149 self.handler.delay_as_bug(self.diagnostic.clone());
153 /// Add a span/label to be included in the resulting snippet.
154 /// This is pushed onto the `MultiSpan` that was created when the
155 /// diagnostic was first built. If you don't call this function at
156 /// all, and you just supplied a `Span` to create the diagnostic,
157 /// then the snippet will just include that `Span`, which is
158 /// called the primary span.
159 pub fn span_label<T: Into<String>>(&mut self, span: Span, label: T) -> &mut Self {
160 self.diagnostic.span_label(span, label);
164 forward!(pub fn note_expected_found(&mut self,
165 label: &dyn fmt::Display,
166 expected: DiagnosticStyledString,
167 found: DiagnosticStyledString,
170 forward!(pub fn note_expected_found_extra(&mut self,
171 label: &dyn fmt::Display,
172 expected: DiagnosticStyledString,
173 found: DiagnosticStyledString,
174 expected_extra: &dyn fmt::Display,
175 found_extra: &dyn fmt::Display,
178 forward!(pub fn note(&mut self, msg: &str) -> &mut Self);
179 forward!(pub fn span_note<S: Into<MultiSpan>>(&mut self,
183 forward!(pub fn warn(&mut self, msg: &str) -> &mut Self);
184 forward!(pub fn span_warn<S: Into<MultiSpan>>(&mut self, sp: S, msg: &str) -> &mut Self);
185 forward!(pub fn help(&mut self , msg: &str) -> &mut Self);
186 forward!(pub fn span_help<S: Into<MultiSpan>>(&mut self,
191 pub fn multipart_suggestion(
194 suggestion: Vec<(Span, String)>,
195 applicability: Applicability,
197 if !self.allow_suggestions {
200 self.diagnostic.multipart_suggestion(
208 pub fn span_suggestion(
213 applicability: Applicability,
215 if !self.allow_suggestions {
218 self.diagnostic.span_suggestion(
227 pub fn span_suggestions(
231 suggestions: impl Iterator<Item = String>,
232 applicability: Applicability,
234 if !self.allow_suggestions {
237 self.diagnostic.span_suggestions(
246 pub fn span_suggestion_short(
251 applicability: Applicability,
253 if !self.allow_suggestions {
256 self.diagnostic.span_suggestion_short(
265 pub fn span_suggestion_hidden(
270 applicability: Applicability,
272 if !self.allow_suggestions {
275 self.diagnostic.span_suggestion_hidden(
284 pub fn tool_only_span_suggestion(
289 applicability: Applicability,
291 if !self.allow_suggestions {
294 self.diagnostic.tool_only_span_suggestion(
303 forward!(pub fn set_span<S: Into<MultiSpan>>(&mut self, sp: S) -> &mut Self);
304 forward!(pub fn code(&mut self, s: DiagnosticId) -> &mut Self);
306 pub fn allow_suggestions(&mut self, allow: bool) -> &mut Self {
307 self.allow_suggestions = allow;
311 /// Convenience function for internal use, clients should use one of the
312 /// struct_* methods on Handler.
313 pub fn new(handler: &'a Handler, level: Level, message: &str) -> DiagnosticBuilder<'a> {
314 DiagnosticBuilder::new_with_code(handler, level, None, message)
317 /// Convenience function for internal use, clients should use one of the
318 /// struct_* methods on Handler.
319 pub fn new_with_code(handler: &'a Handler,
321 code: Option<DiagnosticId>,
323 -> DiagnosticBuilder<'a> {
324 let diagnostic = Diagnostic::new_with_code(level, code, message);
325 DiagnosticBuilder::new_diagnostic(handler, diagnostic)
328 /// Creates a new `DiagnosticBuilder` with an already constructed
330 pub fn new_diagnostic(handler: &'a Handler, diagnostic: Diagnostic)
331 -> DiagnosticBuilder<'a> {
335 allow_suggestions: true,
340 impl<'a> Debug for DiagnosticBuilder<'a> {
341 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
342 self.diagnostic.fmt(f)
346 /// Destructor bomb - a `DiagnosticBuilder` must be either emitted or canceled
347 /// or we emit a bug.
348 impl<'a> Drop for DiagnosticBuilder<'a> {
350 if !panicking() && !self.cancelled() {
351 let mut db = DiagnosticBuilder::new(self.handler,
353 "Error constructed but not emitted");