diff --git a/src/protocol/ast.rs b/src/protocol/ast.rs
index ac14cd4da6bc831eaa42b9634a9685e8e0df4e7c..963ce83536af446eea6ce31f725582b268763a18 100644
--- a/src/protocol/ast.rs
+++ b/src/protocol/ast.rs
@@ -733,7 +733,7 @@ impl StructDefinition {
     }
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, Copy)]
 pub enum EnumVariantValue {
     None,
     Integer(i64),
@@ -766,17 +766,11 @@ impl EnumDefinition {
     }
 }
 
-#[derive(Debug, Clone)]
-pub enum UnionVariantValue {
-    None,
-    Embedded(Vec<ParserType>),
-}
-
 #[derive(Debug, Clone)]
 pub struct UnionVariantDefinition {
     pub span: InputSpan,
     pub identifier: Identifier,
-    pub value: UnionVariantValue,
+    pub value: Vec<ParserType>, // if empty, then union variant does not contain any embedded types
 }
 
 #[derive(Debug, Clone)]