Rollup merge of #139653 - nnethercote:fix-139495, r=petrochenkov

Handle a negated literal in `eat_token_lit`.

Fixes #139495.

r? `@petrochenkov`

1 files changed, 9 insertions, 4 deletions

diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index 9c457f150a3..d52e36fcfac 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -2166,10 +2166,15 @@ impl<'a> Parser<'a> {
                 let expr = self
                     .eat_metavar_seq(mv_kind, |this| this.parse_expr())
                     .expect("metavar seq expr");
-                let ast::ExprKind::Lit(token_lit) = expr.kind else {
-                    panic!("didn't reparse an expr");
-                };
-                Some(token_lit)
+                if let ast::ExprKind::Lit(token_lit) = expr.kind {
+                    Some(token_lit)
+                } else if let ast::ExprKind::Unary(UnOp::Neg, inner) = &expr.kind
+                    && let ast::Expr { kind: ast::ExprKind::Lit(_), .. } = **inner
+                {
+                    None
+                } else {
+                    panic!("unexpected reparsed expr: {:?}", expr.kind);
+                }
             }
             _ => None,
         }