Auto merge of #88386 - estebank:unmatched-delims, r=jackh726

Point at unclosed delimiters as part of the primary MultiSpan

Both the place where the parser encounters a needed closed delimiter and
the unclosed opening delimiter are important, so they should get the
same level of highlighting in the output.

_Context: https://twitter.com/mwk4/status/1430631546432675840_

2 files changed, 18 insertions, 3 deletions

diff --git a/compiler/rustc_parse/src/parser/diagnostics.rs b/compiler/rustc_parse/src/parser/diagnostics.rs
index 273fbea3580..cdc1d1cf99f 100644
--- a/compiler/rustc_parse/src/parser/diagnostics.rs
+++ b/compiler/rustc_parse/src/parser/diagnostics.rs
@@ -1432,12 +1432,22 @@ impl<'a> Parser<'a> {
                 // the most sense, which is immediately after the last token:
                 //
                 //  {foo(bar {}}
-                //      -      ^
+                //      ^      ^
                 //      |      |
                 //      |      help: `)` may belong here
                 //      |
                 //      unclosed delimiter
                 if let Some(sp) = unmatched.unclosed_span {
+                    let mut primary_span: Vec<Span> =
+                        err.span.primary_spans().iter().cloned().collect();
+                    primary_span.push(sp);
+                    let mut primary_span: MultiSpan = primary_span.into();
+                    for span_label in err.span.span_labels() {
+                        if let Some(label) = span_label.label {
+                            primary_span.push_span_label(span_label.span, label);
+                        }
+                    }
+                    err.set_span(primary_span);
                     err.span_label(sp, "unclosed delimiter");
                 }
                 // Backticks should be removed to apply suggestions.
diff --git a/compiler/rustc_parse/src/parser/mod.rs b/compiler/rustc_parse/src/parser/mod.rs
index c34fd02e806..c4419e995ed 100644
--- a/compiler/rustc_parse/src/parser/mod.rs
+++ b/compiler/rustc_parse/src/parser/mod.rs
@@ -33,7 +33,7 @@ use rustc_data_structures::sync::Lrc;
 use rustc_errors::PResult;
 use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder, FatalError};
 use rustc_session::parse::ParseSess;
-use rustc_span::source_map::{Span, DUMMY_SP};
+use rustc_span::source_map::{MultiSpan, Span, DUMMY_SP};
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use tracing::debug;
 
@@ -1335,8 +1335,13 @@ crate fn make_unclosed_delims_error(
     // `None` here means an `Eof` was found. We already emit those errors elsewhere, we add them to
     // `unmatched_braces` only for error recovery in the `Parser`.
     let found_delim = unmatched.found_delim?;
+    let span: MultiSpan = if let Some(sp) = unmatched.unclosed_span {
+        vec![unmatched.found_span, sp].into()
+    } else {
+        unmatched.found_span.into()
+    };
     let mut err = sess.span_diagnostic.struct_span_err(
-        unmatched.found_span,
+        span,
         &format!(
             "mismatched closing delimiter: `{}`",
             pprust::token_kind_to_string(&token::CloseDelim(found_delim)),