Rollup merge of #141318 - nnethercote:fix-140884, r=compiler-errors

Avoid creating an empty identifer in `Symbol::to_ident_string`.

Because that causes an assertion failure in debug builds.

Fixes #140884.

r? `@oli-obk`

1 files changed, 2 insertions, 1 deletions

diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index efae6250b07..fbe3b4ca6f5 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -2592,7 +2592,8 @@ impl Symbol {
     /// (`token_to_string`, `Ident::to_string`), except that symbols don't keep the rawness flag
     /// or edition, so we have to guess the rawness using the global edition.
     pub fn to_ident_string(self) -> String {
-        Ident::with_dummy_span(self).to_string()
+        // Avoid creating an empty identifier, because that asserts in debug builds.
+        if self == kw::Empty { String::new() } else { Ident::with_dummy_span(self).to_string() }
     }
 }