1 //! Contains `ParseSess` which holds state living beyond what one `Parser` might.
2 //! It also serves as an input to the parser itself.
4 use crate::config::CheckCfg;
5 use crate::errors::{FeatureDiagnosticForIssue, FeatureDiagnosticHelp, FeatureGateError};
7 builtin::UNSTABLE_SYNTAX_PRE_EXPANSION, BufferedEarlyLint, BuiltinLintDiagnostics, Lint, LintId,
9 use rustc_ast::node_id::NodeId;
10 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexSet};
11 use rustc_data_structures::sync::{Lock, Lrc};
12 use rustc_errors::{emitter::SilentEmitter, ColorConfig, Handler};
14 fallback_fluent_bundle, Applicability, Diagnostic, DiagnosticBuilder, DiagnosticId,
15 DiagnosticMessage, EmissionGuarantee, ErrorGuaranteed, IntoDiagnostic, MultiSpan, StashKey,
17 use rustc_feature::{find_feature_issue, GateIssue, UnstableFeatures};
18 use rustc_span::edition::Edition;
19 use rustc_span::hygiene::ExpnId;
20 use rustc_span::source_map::{FilePathMapping, SourceMap};
21 use rustc_span::{Span, Symbol};
23 use rustc_ast::attr::AttrIdGenerator;
26 /// The set of keys (and, optionally, values) that define the compilation
27 /// environment of the crate, used to drive conditional compilation.
28 pub type CrateConfig = FxIndexSet<(Symbol, Option<Symbol>)>;
29 pub type CrateCheckConfig = CheckCfg<Symbol>;
31 /// Collected spans during parsing for places where a certain feature was
32 /// used and should be feature gated accordingly in `check_crate`.
34 pub struct GatedSpans {
35 pub spans: Lock<FxHashMap<Symbol, Vec<Span>>>,
39 /// Feature gate the given `span` under the given `feature`
40 /// which is same `Symbol` used in `active.rs`.
41 pub fn gate(&self, feature: Symbol, span: Span) {
42 self.spans.borrow_mut().entry(feature).or_default().push(span);
45 /// Ungate the last span under the given `feature`.
46 /// Panics if the given `span` wasn't the last one.
48 /// Using this is discouraged unless you have a really good reason to.
49 pub fn ungate_last(&self, feature: Symbol, span: Span) {
50 let removed_span = self.spans.borrow_mut().entry(feature).or_default().pop().unwrap();
51 debug_assert_eq!(span, removed_span);
54 /// Is the provided `feature` gate ungated currently?
56 /// Using this is discouraged unless you have a really good reason to.
57 pub fn is_ungated(&self, feature: Symbol) -> bool {
58 self.spans.borrow().get(&feature).map_or(true, |spans| spans.is_empty())
61 /// Prepend the given set of `spans` onto the set in `self`.
62 pub fn merge(&self, mut spans: FxHashMap<Symbol, Vec<Span>>) {
63 let mut inner = self.spans.borrow_mut();
64 for (gate, mut gate_spans) in inner.drain() {
65 spans.entry(gate).or_default().append(&mut gate_spans);
72 pub struct SymbolGallery {
73 /// All symbols occurred and their first occurrence span.
74 pub symbols: Lock<FxHashMap<Symbol, Span>>,
78 /// Insert a symbol and its span into symbol gallery.
79 /// If the symbol has occurred before, ignore the new occurrence.
80 pub fn insert(&self, symbol: Symbol, span: Span) {
81 self.symbols.lock().entry(symbol).or_insert(span);
85 /// Construct a diagnostic for a language feature error due to the given `span`.
86 /// The `feature`'s `Symbol` is the one you used in `active.rs` and `rustc_span::symbols`.
87 pub fn feature_err<'a>(
90 span: impl Into<MultiSpan>,
92 ) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
93 feature_err_issue(sess, feature, span, GateIssue::Language, explain)
96 /// Construct a diagnostic for a feature gate error.
98 /// This variant allows you to control whether it is a library or language feature.
99 /// Almost always, you want to use this for a language feature. If so, prefer `feature_err`.
100 pub fn feature_err_issue<'a>(
103 span: impl Into<MultiSpan>,
106 ) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
107 let span = span.into();
109 // Cancel an earlier warning for this same error, if it exists.
110 if let Some(span) = span.primary_span() {
112 .steal_diagnostic(span, StashKey::EarlySyntaxWarning)
113 .map(|err| err.cancel());
116 let mut err = sess.create_err(FeatureGateError { span, explain });
117 add_feature_diagnostics_for_issue(&mut err, sess, feature, issue);
121 /// Construct a future incompatibility diagnostic for a feature gate.
123 /// This diagnostic is only a warning and *does not cause compilation to fail*.
124 pub fn feature_warn<'a>(sess: &'a ParseSess, feature: Symbol, span: Span, explain: &str) {
125 feature_warn_issue(sess, feature, span, GateIssue::Language, explain);
128 /// Construct a future incompatibility diagnostic for a feature gate.
130 /// This diagnostic is only a warning and *does not cause compilation to fail*.
132 /// This variant allows you to control whether it is a library or language feature.
133 /// Almost always, you want to use this for a language feature. If so, prefer `feature_warn`.
134 #[allow(rustc::diagnostic_outside_of_impl)]
135 #[allow(rustc::untranslatable_diagnostic)]
136 pub fn feature_warn_issue<'a>(
143 let mut err = sess.span_diagnostic.struct_span_warn(span, explain);
144 add_feature_diagnostics_for_issue(&mut err, sess, feature, issue);
146 // Decorate this as a future-incompatibility lint as in rustc_middle::lint::struct_lint_level
147 let lint = UNSTABLE_SYNTAX_PRE_EXPANSION;
148 let future_incompatible = lint.future_incompatible.as_ref().unwrap();
149 err.code(DiagnosticId::Lint {
150 name: lint.name_lower(),
151 has_future_breakage: false,
152 is_force_warn: false,
155 err.note(format!("for more information, see {}", future_incompatible.reference));
157 // A later feature_err call can steal and cancel this warning.
158 err.stash(span, StashKey::EarlySyntaxWarning);
161 /// Adds the diagnostics for a feature to an existing error.
162 pub fn add_feature_diagnostics<'a>(err: &mut Diagnostic, sess: &'a ParseSess, feature: Symbol) {
163 add_feature_diagnostics_for_issue(err, sess, feature, GateIssue::Language);
166 /// Adds the diagnostics for a feature to an existing error.
168 /// This variant allows you to control whether it is a library or language feature.
169 /// Almost always, you want to use this for a language feature. If so, prefer
170 /// `add_feature_diagnostics`.
171 pub fn add_feature_diagnostics_for_issue<'a>(
172 err: &mut Diagnostic,
177 if let Some(n) = find_feature_issue(feature, issue) {
178 err.subdiagnostic(FeatureDiagnosticForIssue { n });
181 // #23973: do not suggest `#![feature(...)]` if we are in beta/stable
182 if sess.unstable_features.is_nightly_build() {
183 err.subdiagnostic(FeatureDiagnosticHelp { feature });
187 /// Info about a parsing session.
188 pub struct ParseSess {
189 pub span_diagnostic: Handler,
190 pub unstable_features: UnstableFeatures,
191 pub config: CrateConfig,
192 pub check_config: CrateCheckConfig,
193 pub edition: Edition,
194 /// Places where raw identifiers were used. This is used to avoid complaining about idents
195 /// clashing with keywords in new editions.
196 pub raw_identifier_spans: Lock<Vec<Span>>,
197 /// Places where identifiers that contain invalid Unicode codepoints but that look like they
198 /// should be. Useful to avoid bad tokenization when encountering emoji. We group them to
199 /// provide a single error per unique incorrect identifier.
200 pub bad_unicode_identifiers: Lock<FxHashMap<Symbol, Vec<Span>>>,
201 source_map: Lrc<SourceMap>,
202 pub buffered_lints: Lock<Vec<BufferedEarlyLint>>,
203 /// Contains the spans of block expressions that could have been incomplete based on the
204 /// operation token that followed it, but that the parser cannot identify without further
206 pub ambiguous_block_expr_parse: Lock<FxHashMap<Span, Span>>,
207 pub gated_spans: GatedSpans,
208 pub symbol_gallery: SymbolGallery,
209 /// The parser has reached `Eof` due to an unclosed brace. Used to silence unnecessary errors.
210 pub reached_eof: Lock<bool>,
211 /// Environment variables accessed during the build and their values when they exist.
212 pub env_depinfo: Lock<FxHashSet<(Symbol, Option<Symbol>)>>,
213 /// File paths accessed during the build.
214 pub file_depinfo: Lock<FxHashSet<Symbol>>,
215 /// All the type ascriptions expressions that have had a suggestion for likely path typo.
216 pub type_ascription_path_suggestions: Lock<FxHashSet<Span>>,
217 /// Whether cfg(version) should treat the current release as incomplete
218 pub assume_incomplete_release: bool,
219 /// Spans passed to `proc_macro::quote_span`. Each span has a numerical
220 /// identifier represented by its position in the vector.
221 pub proc_macro_quoted_spans: Lock<Vec<Span>>,
222 /// Used to generate new `AttrId`s. Every `AttrId` is unique.
223 pub attr_id_generator: AttrIdGenerator,
227 /// Used for testing.
228 pub fn new(file_path_mapping: FilePathMapping) -> Self {
229 let fallback_bundle = fallback_fluent_bundle(rustc_errors::DEFAULT_LOCALE_RESOURCES, false);
230 let sm = Lrc::new(SourceMap::new(file_path_mapping));
231 let handler = Handler::with_tty_emitter(
239 ParseSess::with_span_handler(handler, sm)
242 pub fn with_span_handler(handler: Handler, source_map: Lrc<SourceMap>) -> Self {
244 span_diagnostic: handler,
245 unstable_features: UnstableFeatures::from_environment(None),
246 config: FxIndexSet::default(),
247 check_config: CrateCheckConfig::default(),
248 edition: ExpnId::root().expn_data().edition,
249 raw_identifier_spans: Lock::new(Vec::new()),
250 bad_unicode_identifiers: Lock::new(Default::default()),
252 buffered_lints: Lock::new(vec![]),
253 ambiguous_block_expr_parse: Lock::new(FxHashMap::default()),
254 gated_spans: GatedSpans::default(),
255 symbol_gallery: SymbolGallery::default(),
256 reached_eof: Lock::new(false),
257 env_depinfo: Default::default(),
258 file_depinfo: Default::default(),
259 type_ascription_path_suggestions: Default::default(),
260 assume_incomplete_release: false,
261 proc_macro_quoted_spans: Default::default(),
262 attr_id_generator: AttrIdGenerator::new(),
266 pub fn with_silent_emitter(fatal_note: Option<String>) -> Self {
267 let fallback_bundle = fallback_fluent_bundle(rustc_errors::DEFAULT_LOCALE_RESOURCES, false);
268 let sm = Lrc::new(SourceMap::new(FilePathMapping::empty()));
270 Handler::with_tty_emitter(ColorConfig::Auto, false, None, None, None, fallback_bundle);
271 let handler = Handler::with_emitter(
274 Box::new(SilentEmitter { fatal_handler, fatal_note }),
276 ParseSess::with_span_handler(handler, sm)
280 pub fn source_map(&self) -> &SourceMap {
284 pub fn clone_source_map(&self) -> Lrc<SourceMap> {
285 self.source_map.clone()
291 span: impl Into<MultiSpan>,
295 self.buffered_lints.with_lock(|buffered_lints| {
296 buffered_lints.push(BufferedEarlyLint {
300 lint_id: LintId::of(lint),
301 diagnostic: BuiltinLintDiagnostics::Normal,
306 pub fn buffer_lint_with_diagnostic(
309 span: impl Into<MultiSpan>,
312 diagnostic: BuiltinLintDiagnostics,
314 self.buffered_lints.with_lock(|buffered_lints| {
315 buffered_lints.push(BufferedEarlyLint {
319 lint_id: LintId::of(lint),
325 /// Extend an error with a suggestion to wrap an expression with parentheses to allow the
326 /// parser to continue parsing the following operation as part of the same expression.
327 pub fn expr_parentheses_needed(&self, err: &mut Diagnostic, span: Span) {
328 err.multipart_suggestion(
329 "parentheses are required to parse this as an expression",
330 vec![(span.shrink_to_lo(), "(".to_string()), (span.shrink_to_hi(), ")".to_string())],
331 Applicability::MachineApplicable,
335 pub fn save_proc_macro_span(&self, span: Span) -> usize {
336 let mut spans = self.proc_macro_quoted_spans.lock();
338 return spans.len() - 1;
341 pub fn proc_macro_quoted_spans(&self) -> Vec<Span> {
342 self.proc_macro_quoted_spans.lock().clone()
345 pub fn create_err<'a>(
347 err: impl IntoDiagnostic<'a>,
348 ) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
349 err.into_diagnostic(&self.span_diagnostic)
352 pub fn emit_err<'a>(&'a self, err: impl IntoDiagnostic<'a>) -> ErrorGuaranteed {
353 self.create_err(err).emit()
356 pub fn create_warning<'a>(
358 warning: impl IntoDiagnostic<'a, ()>,
359 ) -> DiagnosticBuilder<'a, ()> {
360 warning.into_diagnostic(&self.span_diagnostic)
363 pub fn emit_warning<'a>(&'a self, warning: impl IntoDiagnostic<'a, ()>) {
364 self.create_warning(warning).emit()
367 pub fn create_fatal<'a>(
369 fatal: impl IntoDiagnostic<'a, !>,
370 ) -> DiagnosticBuilder<'a, !> {
371 fatal.into_diagnostic(&self.span_diagnostic)
374 pub fn emit_fatal<'a>(&'a self, fatal: impl IntoDiagnostic<'a, !>) -> ! {
375 self.create_fatal(fatal).emit()
378 #[rustc_lint_diagnostics]
381 msg: impl Into<DiagnosticMessage>,
382 ) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
383 self.span_diagnostic.struct_err(msg)
386 #[rustc_lint_diagnostics]
387 pub fn struct_warn(&self, msg: impl Into<DiagnosticMessage>) -> DiagnosticBuilder<'_, ()> {
388 self.span_diagnostic.struct_warn(msg)
391 #[rustc_lint_diagnostics]
392 pub fn struct_fatal(&self, msg: impl Into<DiagnosticMessage>) -> DiagnosticBuilder<'_, !> {
393 self.span_diagnostic.struct_fatal(msg)
396 #[rustc_lint_diagnostics]
397 pub fn struct_diagnostic<G: EmissionGuarantee>(
399 msg: impl Into<DiagnosticMessage>,
400 ) -> DiagnosticBuilder<'_, G> {
401 self.span_diagnostic.struct_diagnostic(msg)