bjoernager/rust
bjoernager/rust
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add doc comments

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This commit is contained in:
Takayuki Maeda 2022-03-10 19:34:42 +09:00
parent 3ded25204b
commit 2db8236857
2 changed files with 14 additions and 5 deletions
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15
compiler/rustc_parse/src/parser/diagnostics.rs
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@ -156,6 +156,9 @@ impl AttemptLocalParseRecovery {
} }
} }
// SnapshotParser is used to create a snapshot of the parser
// without causing duplicate errors being emitted when the `Parser`
// is dropped.
pub(super) struct SnapshotParser<'a> { pub(super) struct SnapshotParser<'a> {
parser: Parser<'a>, parser: Parser<'a>,
unclosed_delims: Vec<UnmatchedBrace>, unclosed_delims: Vec<UnmatchedBrace>,
@ -200,15 +203,21 @@ impl<'a> Parser<'a> {
&self.sess.span_diagnostic &self.sess.span_diagnostic
} }
pub(super) fn restore(&mut self, snapshot: SnapshotParser<'a>) { /// Relace `self` with `snapshot.parser` and extend `unclosed_delims` with `snapshot.unclosed_delims`.
/// This is to avoid losing unclosed delims errors `create_snapshot_for_diagnostic` clears.
pub(super) fn restore_snapshot(&mut self, snapshot: SnapshotParser<'a>) {
*self = snapshot.parser; *self = snapshot.parser;
self.unclosed_delims.extend(snapshot.unclosed_delims.clone()); self.unclosed_delims.extend(snapshot.unclosed_delims.clone());
} }
pub(super) fn diagnostic_snapshot(&self) -> SnapshotParser<'a> { /// Create a snapshot of the `Parser`.
pub(super) fn create_snapshot_for_diagnostic(&self) -> SnapshotParser<'a> {
let mut snapshot = self.clone(); let mut snapshot = self.clone();
let unclosed_delims = self.unclosed_delims.clone(); let unclosed_delims = self.unclosed_delims.clone();
// initialize unclosed_delims to avoid duplicate errors. // Clear `unclosed_delims` in snapshot to avoid
// duplicate errors being emitted when the `Parser`
// is dropped (which may or may not happen, depending
// if the parsing the snapshot is created for is successful)
snapshot.unclosed_delims.clear(); snapshot.unclosed_delims.clear();
SnapshotParser { parser: snapshot, unclosed_delims } SnapshotParser { parser: snapshot, unclosed_delims }
} }

4
compiler/rustc_parse/src/parser/path.rs
View file

@ -625,14 +625,14 @@ impl<'a> Parser<'a> {
} else if self.check_type() { } else if self.check_type() {
// Parse type argument. // Parse type argument.
let is_const_fn = self.look_ahead(1, |t| t.kind == token::OpenDelim(token::Paren)); let is_const_fn = self.look_ahead(1, |t| t.kind == token::OpenDelim(token::Paren));
let mut snapshot = self.diagnostic_snapshot(); let mut snapshot = self.create_snapshot_for_diagnostic();
match self.parse_ty() { match self.parse_ty() {
Ok(ty) => GenericArg::Type(ty), Ok(ty) => GenericArg::Type(ty),
Err(err) => { Err(err) => {
if is_const_fn { if is_const_fn {
if let Ok(expr) = (*snapshot).parse_expr_res(Restrictions::CONST_EXPR, None) if let Ok(expr) = (*snapshot).parse_expr_res(Restrictions::CONST_EXPR, None)
{ {
self.restore(snapshot); self.restore_snapshot(snapshot);
return Ok(Some(self.dummy_const_arg_needs_braces(err, expr.span))); return Ok(Some(self.dummy_const_arg_needs_braces(err, expr.span)));
} }
} }