1 files changed, 15 insertions, 0 deletions

diff --git a/xtask/src/codegen/gen_syntax.rs b/xtask/src/codegen/gen_syntax.rs
index d9f358513..059538696 100644
--- a/xtask/src/codegen/gen_syntax.rs
+++ b/xtask/src/codegen/gen_syntax.rs
@@ -579,6 +579,21 @@ fn lower_rule(acc: &mut Vec<Field>, grammar: &Grammar, label: Option<&String>, r
         }
         Rule::Labeled { label: l, rule } => {
             assert!(label.is_none());
+            let manually_implemented = matches!(
+                l.as_str(),
+                "lhs"
+                    | "rhs"
+                    | "then_branch"
+                    | "else_branch"
+                    | "start"
+                    | "end"
+                    | "op"
+                    | "index"
+                    | "base"
+            );
+            if manually_implemented {
+                return;
+            }
             lower_rule(acc, grammar, Some(l), rule);
         }
         Rule::Seq(rules) | Rule::Alt(rules) => {