check if snippet is )

compiler/rustc_parse/src/parser/expr.rs

@@ -1210,8 +1210,13 @@ impl<'a> Parser<'a> {
                         // `Enum::Foo { a: 3, b: 4 }` or `Enum::Foo(3, 4)`.
                         self.restore_snapshot(snapshot);
                         let close_paren = self.prev_token.span;
-                        let span = lo.to(self.prev_token.span);
+                        let span = lo.to(close_paren);
-                        if !fields.is_empty() {
+                        if !fields.is_empty() &&
+                            // `token.kind` should not be compared here.
+                            // This is because the `snapshot.token.kind` is treated as the same as
+                            // that of the open delim in `TokenTreesReader::parse_token_tree`, even if they are different.
+                            self.span_to_snippet(close_paren).map_or(false, |snippet| snippet == ")")
+                        {
                             let mut replacement_err = errors::ParenthesesWithStructFields {
                                 span,
                                 r#type: path,

tests/ui/parser/issue-107705.rs

@@ -0,0 +1,3 @@
+// compile-flags: -C debug-assertions
+
+fn f() {a(b:&, //~ ERROR this file contains an unclosed delimiter

tests/ui/parser/issue-107705.stderr

@@ -0,0 +1,10 @@
+error: this file contains an unclosed delimiter
+  --> $DIR/issue-107705.rs:3:67
+   |
+LL | fn f() {a(b:&,
+   |        - - unclosed delimiter                                     ^
+   |        |
+   |        unclosed delimiter
+
+error: aborting due to previous error
+