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Remove a fourth DiagnosticBuilder::emit_without_consuming call.

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The old code was very hard to understand, involving an
`emit_without_consuming` call *and* a `delay_as_bug_without_consuming`
call.

With slight changes both calls can be avoided. Not creating the error
until later is crucial, as is the early return in the `if recovered`
block.

It took me some time to come up with this reworking -- it went through
intermediate states much further from the original code than this final
version -- and it's isn't obvious at a glance that it is equivalent. But
I think it is, and the unchanged test behaviour is good supporting
evidence.

The commit also changes `check_trailing_angle_brackets` to return
`Option<ErrorGuaranteed>`. This provides a stricter proof that it
emitted an error message than asserting `dcx.has_errors().is_some()`,
which would succeed if any error had previously been emitted anywhere.
This commit is contained in:
Nicholas Nethercote
2024-01-05 11:10:18 +11:00
parent 1b6c8e7533
commit c733a0216d
2 changed files with 21 additions and 31 deletions
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17
compiler/rustc_parse/src/parser/diagnostics.rs
View File

@@ -34,8 +34,8 @@ use rustc_ast::{
use rustc_ast_pretty::pprust;
use rustc_data_structures::fx::FxHashSet;
use rustc_errors::{
pluralize, AddToDiagnostic, Applicability, DiagCtxt, Diagnostic, DiagnosticBuilder, FatalError,
PErr, PResult,
pluralize, AddToDiagnostic, Applicability, DiagCtxt, Diagnostic, DiagnosticBuilder,
ErrorGuaranteed, FatalError, PErr, PResult,
};
use rustc_session::errors::ExprParenthesesNeeded;
use rustc_span::source_map::Spanned;
@@ -1049,9 +1049,9 @@ impl<'a> Parser<'a> {
&mut self,
segment: &PathSegment,
end: &[&TokenKind],
) -> bool {
) -> Option<ErrorGuaranteed> {
if !self.may_recover() {
return false;
return None;
}
// This function is intended to be invoked after parsing a path segment where there are two
@@ -1086,7 +1086,7 @@ impl<'a> Parser<'a> {
parsed_angle_bracket_args,
);
if !parsed_angle_bracket_args {
return false;
return None;
}
// Keep the span at the start so we can highlight the sequence of `>` characters to be
@@ -1124,7 +1124,7 @@ impl<'a> Parser<'a> {
number_of_gt, number_of_shr,
);
if number_of_gt < 1 && number_of_shr < 1 {
return false;
return None;
}
// Finally, double check that we have our end token as otherwise this is the
@@ -1139,10 +1139,9 @@ impl<'a> Parser<'a> {
let span = lo.until(self.token.span);
let num_extra_brackets = number_of_gt + number_of_shr * 2;
self.dcx().emit_err(UnmatchedAngleBrackets { span, num_extra_brackets });
return true;
return Some(self.dcx().emit_err(UnmatchedAngleBrackets { span, num_extra_brackets }));
}
false
None
}
/// Check if a method call with an intended turbofish has been written without surrounding