Allow enum with undeclared variants as long as it has explicit repr
diff --git a/syntax/mod.rs b/syntax/mod.rs
index 2a3790c..475cec1 100644
--- a/syntax/mod.rs
+++ b/syntax/mod.rs
@@ -91,6 +91,7 @@
     pub variants: Vec<Variant>,
     pub repr: Atom,
     pub repr_type: Type,
+    pub explicit_repr: bool,
 }
 
 pub struct ExternFn {