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::lint::{BufferedEarlyLint, BuiltinLintDiagnostics, Lint, LintId};
5 use rustc_ast::node_id::NodeId;
6 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
7 use rustc_data_structures::sync::{Lock, Lrc};
8 use rustc_errors::{emitter::SilentEmitter, ColorConfig, Handler};
9 use rustc_errors::{error_code, Applicability, DiagnosticBuilder};
10 use rustc_feature::{find_feature_issue, GateIssue, UnstableFeatures};
11 use rustc_span::edition::Edition;
12 use rustc_span::hygiene::ExpnId;
13 use rustc_span::source_map::{FilePathMapping, SourceMap};
14 use rustc_span::{MultiSpan, Span, Symbol};
18 /// The set of keys (and, optionally, values) that define the compilation
19 /// environment of the crate, used to drive conditional compilation.
20 pub type CrateConfig = FxHashSet<(Symbol, Option<Symbol>)>;
22 /// Collected spans during parsing for places where a certain feature was
23 /// used and should be feature gated accordingly in `check_crate`.
25 pub struct GatedSpans {
26 pub spans: Lock<FxHashMap<Symbol, Vec<Span>>>,
30 /// Feature gate the given `span` under the given `feature`
31 /// which is same `Symbol` used in `active.rs`.
32 pub fn gate(&self, feature: Symbol, span: Span) {
33 self.spans.borrow_mut().entry(feature).or_default().push(span);
36 /// Ungate the last span under the given `feature`.
37 /// Panics if the given `span` wasn't the last one.
39 /// Using this is discouraged unless you have a really good reason to.
40 pub fn ungate_last(&self, feature: Symbol, span: Span) {
41 let removed_span = self.spans.borrow_mut().entry(feature).or_default().pop().unwrap();
42 debug_assert_eq!(span, removed_span);
45 /// Is the provided `feature` gate ungated currently?
47 /// Using this is discouraged unless you have a really good reason to.
48 pub fn is_ungated(&self, feature: Symbol) -> bool {
49 self.spans.borrow().get(&feature).map_or(true, |spans| spans.is_empty())
52 /// Prepend the given set of `spans` onto the set in `self`.
53 pub fn merge(&self, mut spans: FxHashMap<Symbol, Vec<Span>>) {
54 let mut inner = self.spans.borrow_mut();
55 for (gate, mut gate_spans) in inner.drain() {
56 spans.entry(gate).or_default().append(&mut gate_spans);
63 pub struct SymbolGallery {
64 /// All symbols occurred and their first occurrence span.
65 pub symbols: Lock<FxHashMap<Symbol, Span>>,
69 /// Insert a symbol and its span into symbol gallery.
70 /// If the symbol has occurred before, ignore the new occurance.
71 pub fn insert(&self, symbol: Symbol, span: Span) {
72 self.symbols.lock().entry(symbol).or_insert(span);
76 /// Construct a diagnostic for a language feature error due to the given `span`.
77 /// The `feature`'s `Symbol` is the one you used in `active.rs` and `rustc_span::symbols`.
78 pub fn feature_err<'a>(
81 span: impl Into<MultiSpan>,
83 ) -> DiagnosticBuilder<'a> {
84 feature_err_issue(sess, feature, span, GateIssue::Language, explain)
87 /// Construct a diagnostic for a feature gate error.
89 /// This variant allows you to control whether it is a library or language feature.
90 /// Almost always, you want to use this for a language feature. If so, prefer `feature_err`.
91 pub fn feature_err_issue<'a>(
94 span: impl Into<MultiSpan>,
97 ) -> DiagnosticBuilder<'a> {
98 let mut err = sess.span_diagnostic.struct_span_err_with_code(span, explain, error_code!(E0658));
100 if let Some(n) = find_feature_issue(feature, issue) {
102 "see issue #{} <https://github.com/rust-lang/rust/issues/{}> for more information",
107 // #23973: do not suggest `#![feature(...)]` if we are in beta/stable
108 if sess.unstable_features.is_nightly_build() {
109 err.help(&format!("add `#![feature({})]` to the crate attributes to enable", feature));
115 /// Info about a parsing session.
116 pub struct ParseSess {
117 pub span_diagnostic: Handler,
118 pub unstable_features: UnstableFeatures,
119 pub config: CrateConfig,
120 pub edition: Edition,
121 pub missing_fragment_specifiers: Lock<FxHashMap<Span, NodeId>>,
122 /// Places where raw identifiers were used. This is used for feature-gating raw identifiers.
123 pub raw_identifier_spans: Lock<Vec<Span>>,
124 source_map: Lrc<SourceMap>,
125 pub buffered_lints: Lock<Vec<BufferedEarlyLint>>,
126 /// Contains the spans of block expressions that could have been incomplete based on the
127 /// operation token that followed it, but that the parser cannot identify without further
129 pub ambiguous_block_expr_parse: Lock<FxHashMap<Span, Span>>,
130 pub gated_spans: GatedSpans,
131 pub symbol_gallery: SymbolGallery,
132 /// The parser has reached `Eof` due to an unclosed brace. Used to silence unnecessary errors.
133 pub reached_eof: Lock<bool>,
134 /// Environment variables accessed during the build and their values when they exist.
135 pub env_depinfo: Lock<FxHashSet<(Symbol, Option<Symbol>)>>,
136 /// All the type ascriptions expressions that have had a suggestion for likely path typo.
137 pub type_ascription_path_suggestions: Lock<FxHashSet<Span>>,
138 /// Whether cfg(version) should treat the current release as incomplete
139 pub assume_incomplete_release: bool,
140 /// Spans passed to `proc_macro::quote_span`. Each span has a numerical
141 /// identifier represented by its position in the vector.
142 pub proc_macro_quoted_spans: Lock<Vec<Span>>,
146 /// Used for testing.
147 pub fn new(file_path_mapping: FilePathMapping) -> Self {
148 let sm = Lrc::new(SourceMap::new(file_path_mapping));
149 let handler = Handler::with_tty_emitter(ColorConfig::Auto, true, None, Some(sm.clone()));
150 ParseSess::with_span_handler(handler, sm)
153 pub fn with_span_handler(handler: Handler, source_map: Lrc<SourceMap>) -> Self {
155 span_diagnostic: handler,
156 unstable_features: UnstableFeatures::from_environment(None),
157 config: FxHashSet::default(),
158 edition: ExpnId::root().expn_data().edition,
159 missing_fragment_specifiers: Default::default(),
160 raw_identifier_spans: Lock::new(Vec::new()),
162 buffered_lints: Lock::new(vec![]),
163 ambiguous_block_expr_parse: Lock::new(FxHashMap::default()),
164 gated_spans: GatedSpans::default(),
165 symbol_gallery: SymbolGallery::default(),
166 reached_eof: Lock::new(false),
167 env_depinfo: Default::default(),
168 type_ascription_path_suggestions: Default::default(),
169 assume_incomplete_release: false,
170 proc_macro_quoted_spans: Default::default(),
174 pub fn with_silent_emitter() -> Self {
175 let sm = Lrc::new(SourceMap::new(FilePathMapping::empty()));
176 let handler = Handler::with_emitter(false, None, Box::new(SilentEmitter));
177 ParseSess::with_span_handler(handler, sm)
181 pub fn source_map(&self) -> &SourceMap {
185 pub fn clone_source_map(&self) -> Lrc<SourceMap> {
186 self.source_map.clone()
192 span: impl Into<MultiSpan>,
196 self.buffered_lints.with_lock(|buffered_lints| {
197 buffered_lints.push(BufferedEarlyLint {
201 lint_id: LintId::of(lint),
202 diagnostic: BuiltinLintDiagnostics::Normal,
207 pub fn buffer_lint_with_diagnostic(
210 span: impl Into<MultiSpan>,
213 diagnostic: BuiltinLintDiagnostics,
215 self.buffered_lints.with_lock(|buffered_lints| {
216 buffered_lints.push(BufferedEarlyLint {
220 lint_id: LintId::of(lint),
226 /// Extend an error with a suggestion to wrap an expression with parentheses to allow the
227 /// parser to continue parsing the following operation as part of the same expression.
228 pub fn expr_parentheses_needed(
230 err: &mut DiagnosticBuilder<'_>,
232 alt_snippet: Option<String>,
234 if let Some(snippet) = self.source_map().span_to_snippet(span).ok().or(alt_snippet) {
237 "parentheses are required to parse this as an expression",
238 format!("({})", snippet),
239 Applicability::MachineApplicable,
244 pub fn save_proc_macro_span(&self, span: Span) -> usize {
245 let mut spans = self.proc_macro_quoted_spans.lock();
247 return spans.len() - 1;
250 pub fn proc_macro_quoted_spans(&self) -> Vec<Span> {
251 self.proc_macro_quoted_spans.lock().clone()