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, OnceCell}
;
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}
;
16 use std
::path
::PathBuf
;
19 /// The set of keys (and, optionally, values) that define the compilation
20 /// environment of the crate, used to drive conditional compilation.
21 pub type CrateConfig
= FxHashSet
<(Symbol
, Option
<Symbol
>)>;
23 /// Collected spans during parsing for places where a certain feature was
24 /// used and should be feature gated accordingly in `check_crate`.
26 pub struct GatedSpans
{
27 pub spans
: Lock
<FxHashMap
<Symbol
, Vec
<Span
>>>,
31 /// Feature gate the given `span` under the given `feature`
32 /// which is same `Symbol` used in `active.rs`.
33 pub fn gate(&self, feature
: Symbol
, span
: Span
) {
34 self.spans
.borrow_mut().entry(feature
).or_default().push(span
);
37 /// Ungate the last span under the given `feature`.
38 /// Panics if the given `span` wasn't the last one.
40 /// Using this is discouraged unless you have a really good reason to.
41 pub fn ungate_last(&self, feature
: Symbol
, span
: Span
) {
42 let removed_span
= self.spans
.borrow_mut().entry(feature
).or_default().pop().unwrap();
43 debug_assert_eq
!(span
, removed_span
);
46 /// Is the provided `feature` gate ungated currently?
48 /// Using this is discouraged unless you have a really good reason to.
49 pub fn is_ungated(&self, feature
: Symbol
) -> bool
{
50 self.spans
.borrow().get(&feature
).map_or(true, |spans
| spans
.is_empty())
53 /// Prepend the given set of `spans` onto the set in `self`.
54 pub fn merge(&self, mut spans
: FxHashMap
<Symbol
, Vec
<Span
>>) {
55 let mut inner
= self.spans
.borrow_mut();
56 for (gate
, mut gate_spans
) in inner
.drain() {
57 spans
.entry(gate
).or_default().append(&mut gate_spans
);
64 pub struct SymbolGallery
{
65 /// All symbols occurred and their first occurrence span.
66 pub symbols
: Lock
<FxHashMap
<Symbol
, Span
>>,
70 /// Insert a symbol and its span into symbol gallery.
71 /// If the symbol has occurred before, ignore the new occurance.
72 pub fn insert(&self, symbol
: Symbol
, span
: Span
) {
73 self.symbols
.lock().entry(symbol
).or_insert(span
);
77 /// Construct a diagnostic for a language feature error due to the given `span`.
78 /// The `feature`'s `Symbol` is the one you used in `active.rs` and `rustc_span::symbols`.
79 pub fn feature_err
<'a
>(
82 span
: impl Into
<MultiSpan
>,
84 ) -> DiagnosticBuilder
<'a
> {
85 feature_err_issue(sess
, feature
, span
, GateIssue
::Language
, explain
)
88 /// Construct a diagnostic for a feature gate error.
90 /// This variant allows you to control whether it is a library or language feature.
91 /// Almost always, you want to use this for a language feature. If so, prefer `feature_err`.
92 pub fn feature_err_issue
<'a
>(
95 span
: impl Into
<MultiSpan
>,
98 ) -> DiagnosticBuilder
<'a
> {
99 let mut err
= sess
.span_diagnostic
.struct_span_err_with_code(span
, explain
, error_code
!(E0658
));
101 if let Some(n
) = find_feature_issue(feature
, issue
) {
103 "see issue #{} <https://github.com/rust-lang/rust/issues/{}> for more information",
108 // #23973: do not suggest `#![feature(...)]` if we are in beta/stable
109 if sess
.unstable_features
.is_nightly_build() {
110 err
.help(&format
!("add `#![feature({})]` to the crate attributes to enable", feature
));
116 /// Info about a parsing session.
117 pub struct ParseSess
{
118 pub span_diagnostic
: Handler
,
119 pub unstable_features
: UnstableFeatures
,
120 pub config
: CrateConfig
,
121 pub edition
: Edition
,
122 pub missing_fragment_specifiers
: Lock
<FxHashMap
<Span
, NodeId
>>,
123 /// Places where raw identifiers were used. This is used for feature-gating raw identifiers.
124 pub raw_identifier_spans
: Lock
<Vec
<Span
>>,
125 /// Used to determine and report recursive module inclusions.
126 pub included_mod_stack
: Lock
<Vec
<PathBuf
>>,
127 source_map
: Lrc
<SourceMap
>,
128 pub buffered_lints
: Lock
<Vec
<BufferedEarlyLint
>>,
129 /// Contains the spans of block expressions that could have been incomplete based on the
130 /// operation token that followed it, but that the parser cannot identify without further
132 pub ambiguous_block_expr_parse
: Lock
<FxHashMap
<Span
, Span
>>,
133 pub injected_crate_name
: OnceCell
<Symbol
>,
134 pub gated_spans
: GatedSpans
,
135 pub symbol_gallery
: SymbolGallery
,
136 /// The parser has reached `Eof` due to an unclosed brace. Used to silence unnecessary errors.
137 pub reached_eof
: Lock
<bool
>,
138 /// Environment variables accessed during the build and their values when they exist.
139 pub env_depinfo
: Lock
<FxHashSet
<(Symbol
, Option
<Symbol
>)>>,
140 /// All the type ascriptions expressions that have had a suggestion for likely path typo.
141 pub type_ascription_path_suggestions
: Lock
<FxHashSet
<Span
>>,
145 pub fn new(file_path_mapping
: FilePathMapping
) -> Self {
146 let sm
= Lrc
::new(SourceMap
::new(file_path_mapping
));
147 let handler
= Handler
::with_tty_emitter(ColorConfig
::Auto
, true, None
, Some(sm
.clone()));
148 ParseSess
::with_span_handler(handler
, sm
)
151 pub fn with_span_handler(handler
: Handler
, source_map
: Lrc
<SourceMap
>) -> Self {
153 span_diagnostic
: handler
,
154 unstable_features
: UnstableFeatures
::from_environment(),
155 config
: FxHashSet
::default(),
156 edition
: ExpnId
::root().expn_data().edition
,
157 missing_fragment_specifiers
: Default
::default(),
158 raw_identifier_spans
: Lock
::new(Vec
::new()),
159 included_mod_stack
: Lock
::new(vec
![]),
161 buffered_lints
: Lock
::new(vec
![]),
162 ambiguous_block_expr_parse
: Lock
::new(FxHashMap
::default()),
163 injected_crate_name
: OnceCell
::new(),
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(),
172 pub fn with_silent_emitter() -> Self {
173 let sm
= Lrc
::new(SourceMap
::new(FilePathMapping
::empty()));
174 let handler
= Handler
::with_emitter(false, None
, Box
::new(SilentEmitter
));
175 ParseSess
::with_span_handler(handler
, sm
)
179 pub fn source_map(&self) -> &SourceMap
{
183 pub fn clone_source_map(&self) -> Lrc
<SourceMap
> {
184 self.source_map
.clone()
190 span
: impl Into
<MultiSpan
>,
194 self.buffered_lints
.with_lock(|buffered_lints
| {
195 buffered_lints
.push(BufferedEarlyLint
{
199 lint_id
: LintId
::of(lint
),
200 diagnostic
: BuiltinLintDiagnostics
::Normal
,
205 pub fn buffer_lint_with_diagnostic(
208 span
: impl Into
<MultiSpan
>,
211 diagnostic
: BuiltinLintDiagnostics
,
213 self.buffered_lints
.with_lock(|buffered_lints
| {
214 buffered_lints
.push(BufferedEarlyLint
{
218 lint_id
: LintId
::of(lint
),
224 /// Extend an error with a suggestion to wrap an expression with parentheses to allow the
225 /// parser to continue parsing the following operation as part of the same expression.
226 pub fn expr_parentheses_needed(
228 err
: &mut DiagnosticBuilder
<'_
>,
230 alt_snippet
: Option
<String
>,
232 if let Some(snippet
) = self.source_map().span_to_snippet(span
).ok().or(alt_snippet
) {
235 "parentheses are required to parse this as an expression",
236 format
!("({})", snippet
),
237 Applicability
::MachineApplicable
,