Rust: make Adt be generated

rust/ast-generator/src/main.rs

@@ -385,8 +385,8 @@ struct ExtractorInfo {
 }
 
 fn enum_to_extractor_info(node: &AstEnumSrc) -> Option<ExtractorEnumInfo> {
-    if node.name == "VariantDef" {
-        // currently defined but unused
+    if matches!(node.name.as_str(), "VariantDef" | "Adt") {
+        // these are not used as types of fields, so we don't need to generate extractors for them
         return None;
     }
     Some(ExtractorEnumInfo {
@@ -485,8 +485,6 @@ fn main() -> anyhow::Result<()> {
         .expect("Failed to parse grammar");
     let mut grammar = codegen::grammar::lower(&grammar);
 
-    grammar.enums.retain(|x| x.name != "Adt");
-
     let mut super_types: BTreeMap<String, BTreeSet<String>> = BTreeMap::new();
     for node in &grammar.enums {
         for variant in &node.variants {