Fix mbe fail to pass expr with attr

crates/mbe/src/tests.rs

@@ -760,6 +760,18 @@ fn test_last_expr() {
     );
 }
 
+#[test]
+fn test_expr_with_attr() {
+    parse_macro(
+        r#"
+macro_rules! m {
+    ($a:expr) => {0}
+}
+"#,
+    )
+    .assert_expand_items("m!(#[allow(a)]())", "0");
+}
+
 #[test]
 fn test_ty() {
     parse_macro(

crates/parser/src/grammar.rs

@@ -59,7 +59,7 @@ pub(crate) mod fragments {
     };
 
     pub(crate) fn expr(p: &mut Parser) {
-        let _ = expressions::expr(p);
+        let _ = expressions::expr_with_attrs(p);
     }
 
     pub(crate) fn stmt(p: &mut Parser) {