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//! Contains `ParseSess` which holds state living beyond what one `Parser` might.
//! It also serves as an input to the parser itself.
use crate::ast::{CrateConfig, NodeId};
use crate::early_buffered_lints::{BufferedEarlyLint, BufferedEarlyLintId};
use crate::source_map::{SourceMap, FilePathMapping};
use crate::feature_gate::UnstableFeatures;
use errors::{Applicability, Handler, ColorConfig, DiagnosticBuilder};
use rustc_data_structures::fx::{FxHashSet, FxHashMap};
use rustc_data_structures::sync::{Lrc, Lock, Once};
use syntax_pos::{Symbol, Span, MultiSpan};
use syntax_pos::edition::Edition;
use syntax_pos::hygiene::ExpnId;
use std::path::PathBuf;
use std::str;
/// Collected spans during parsing for places where a certain feature was
/// used and should be feature gated accordingly in `check_crate`.
#[derive(Default)]
crate struct GatedSpans {
/// Spans collected for gating `let_chains`, e.g. `if a && let b = c {}`.
crate let_chains: Lock<Vec<Span>>,
/// Spans collected for gating `async_closure`, e.g. `async || ..`.
crate async_closure: Lock<Vec<Span>>,
/// Spans collected for gating `yield e?` expressions (`generators` gate).
crate yields: Lock<Vec<Span>>,
/// Spans collected for gating `or_patterns`, e.g. `Some(Foo | Bar)`.
crate or_patterns: Lock<Vec<Span>>,
/// Spans collected for gating `const_extern_fn`, e.g. `const extern fn foo`.
crate const_extern_fn: Lock<Vec<Span>>,
/// Spans collected for gating `trait_alias`, e.g. `trait Foo = Ord + Eq;`.
pub trait_alias: Lock<Vec<Span>>,
/// Spans collected for gating `associated_type_bounds`, e.g. `Iterator<Item: Ord>`.
pub associated_type_bounds: Lock<Vec<Span>>,
/// Spans collected for gating `crate_visibility_modifier`, e.g. `crate fn`.
pub crate_visibility_modifier: Lock<Vec<Span>>,
/// Spans collected for gating `const_generics`, e.g. `const N: usize`.
pub const_generics: Lock<Vec<Span>>,
/// Spans collected for gating `decl_macro`, e.g. `macro m() {}`.
pub decl_macro: Lock<Vec<Span>>,
/// Spans collected for gating `box_patterns`, e.g. `box 0`.
pub box_patterns: Lock<Vec<Span>>,
/// Spans collected for gating `exclusive_range_pattern`, e.g. `0..2`.
pub exclusive_range_pattern: Lock<Vec<Span>>,
/// Spans collected for gating `try_blocks`, e.g. `try { a? + b? }`.
pub try_blocks: Lock<Vec<Span>>,
/// Spans collected for gating `label_break_value`, e.g. `'label: { ... }`.
pub label_break_value: Lock<Vec<Span>>,
/// Spans collected for gating `box_syntax`, e.g. `box $expr`.
pub box_syntax: Lock<Vec<Span>>,
/// Spans collected for gating `type_ascription`, e.g. `42: usize`.
pub type_ascription: Lock<Vec<Span>>,
}
/// Info about a parsing session.
pub struct ParseSess {
pub span_diagnostic: Handler,
crate unstable_features: UnstableFeatures,
pub config: CrateConfig,
pub edition: Edition,
pub missing_fragment_specifiers: Lock<FxHashSet<Span>>,
/// Places where raw identifiers were used. This is used for feature-gating raw identifiers.
pub raw_identifier_spans: Lock<Vec<Span>>,
/// Used to determine and report recursive module inclusions.
pub(super) included_mod_stack: Lock<Vec<PathBuf>>,
source_map: Lrc<SourceMap>,
pub buffered_lints: Lock<Vec<BufferedEarlyLint>>,
/// Contains the spans of block expressions that could have been incomplete based on the
/// operation token that followed it, but that the parser cannot identify without further
/// analysis.
pub ambiguous_block_expr_parse: Lock<FxHashMap<Span, Span>>,
pub injected_crate_name: Once<Symbol>,
crate gated_spans: GatedSpans,
/// The parser has reached `Eof` due to an unclosed brace. Used to silence unnecessary errors.
pub reached_eof: Lock<bool>,
}
impl ParseSess {
pub fn new(file_path_mapping: FilePathMapping) -> Self {
let cm = Lrc::new(SourceMap::new(file_path_mapping));
let handler = Handler::with_tty_emitter(
ColorConfig::Auto,
true,
None,
Some(cm.clone()),
);
ParseSess::with_span_handler(handler, cm)
}
pub fn with_span_handler(handler: Handler, source_map: Lrc<SourceMap>) -> Self {
Self {
span_diagnostic: handler,
unstable_features: UnstableFeatures::from_environment(),
config: FxHashSet::default(),
edition: ExpnId::root().expn_data().edition,
missing_fragment_specifiers: Lock::new(FxHashSet::default()),
raw_identifier_spans: Lock::new(Vec::new()),
included_mod_stack: Lock::new(vec![]),
source_map,
buffered_lints: Lock::new(vec![]),
ambiguous_block_expr_parse: Lock::new(FxHashMap::default()),
injected_crate_name: Once::new(),
gated_spans: GatedSpans::default(),
reached_eof: Lock::new(false),
}
}
#[inline]
pub fn source_map(&self) -> &SourceMap {
&self.source_map
}
pub fn buffer_lint(
&self,
lint_id: BufferedEarlyLintId,
span: impl Into<MultiSpan>,
id: NodeId,
msg: &str,
) {
self.buffered_lints.with_lock(|buffered_lints| {
buffered_lints.push(BufferedEarlyLint{
span: span.into(),
id,
msg: msg.into(),
lint_id,
});
});
}
/// Extend an error with a suggestion to wrap an expression with parentheses to allow the
/// parser to continue parsing the following operation as part of the same expression.
pub fn expr_parentheses_needed(
&self,
err: &mut DiagnosticBuilder<'_>,
span: Span,
alt_snippet: Option<String>,
) {
if let Some(snippet) = self.source_map().span_to_snippet(span).ok().or(alt_snippet) {
err.span_suggestion(
span,
"parentheses are required to parse this as an expression",
format!("({})", snippet),
Applicability::MachineApplicable,
);
}
}
}
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