bjoernager/rust
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Recover ternary expression as error

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This commit is contained in:
clubby789 2023-10-26 11:35:11 +00:00
parent 041f0313cf
commit e81a5c65d9
3 changed files with 22 additions and 139 deletions
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20
compiler/rustc_parse/src/parser/diagnostics.rs
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@ -504,8 +504,10 @@ impl<'a> Parser<'a> {
// Special-case "expected `;`" errors
if expected.contains(&TokenType::Token(token::Semi)) {
if self.prev_token == token::Question && self.maybe_recover_from_ternary_operator() {
return Ok(true);
// If the user is trying to write a ternary expression, recover it and
// return an Err to prevent a cascade of irrelevant diagnostics
if self.prev_token == token::Question && let Err(e) = self.maybe_recover_from_ternary_operator() {
return Err(e);
}
if self.token.span == DUMMY_SP || self.prev_token.span == DUMMY_SP {
@ -1428,10 +1430,10 @@ impl<'a> Parser<'a> {
/// Rust has no ternary operator (`cond ? then : else`). Parse it and try
/// to recover from it if `then` and `else` are valid expressions. Returns
/// whether it was a ternary operator.
pub(super) fn maybe_recover_from_ternary_operator(&mut self) -> bool {
/// an err if this appears to be a ternary expression.
pub(super) fn maybe_recover_from_ternary_operator(&mut self) -> PResult<'a, ()> {
if self.prev_token != token::Question {
return false;
return PResult::Ok(());
}
let lo = self.prev_token.span.lo();
@ -1449,8 +1451,9 @@ impl<'a> Parser<'a> {
if self.eat_noexpect(&token::Colon) {
match self.parse_expr() {
Ok(_) => {
self.sess.emit_err(TernaryOperator { span: self.token.span.with_lo(lo) });
return true;
return Err(self
.sess
.create_err(TernaryOperator { span: self.token.span.with_lo(lo) }));
}
Err(err) => {
err.cancel();
@ -1459,8 +1462,7 @@ impl<'a> Parser<'a> {
}
}
self.restore_snapshot(snapshot);
false
Ok(())
}
pub(super) fn maybe_recover_from_bad_type_plus(&mut self, ty: &Ty) -> PResult<'a, ()> {