2 files changed, 8 insertions, 1 deletions
diff --git a/mingling_core/src/renderer/structural/error.rs b/mingling_core/src/renderer/structural/error.rs
index a7fbc75..63ded81 100644
--- a/mingling_core/src/renderer/structural/error.rs
+++ b/mingling_core/src/renderer/structural/error.rs
@@ -9,6 +9,7 @@ pub struct StructuralRendererSerializeError {
 }
 
 impl StructuralRendererSerializeError {
+    /// Creates a new `StructuralRendererSerializeError` with the given error message.
     #[must_use]
     pub fn new(error: String) -> Self {
         Self { error }
diff --git a/mingling_core/src/renderer/structural/structural_data.rs b/mingling_core/src/renderer/structural/structural_data.rs
index 1cafac3..583808c 100644
--- a/mingling_core/src/renderer/structural/structural_data.rs
+++ b/mingling_core/src/renderer/structural/structural_data.rs
@@ -1,5 +1,7 @@
 use serde::Serialize;
 
+use crate::ProgramCollect;
+
 /// Marker trait for types that support structured output (JSON / YAML / TOML / RON).
 ///
 /// This trait is a **supertrait** of `serde::Serialize` and is sealed via
@@ -12,4 +14,8 @@ use serde::Serialize;
 /// These entry points also register the type in the global `STRUCTURED_TYPES`
 /// registry, which is required for the `structural_render` match arm to be generated.
 #[doc(hidden)]
-pub trait StructuralData: Serialize + crate::__private::StructuralDataSealed {}
+pub trait StructuralData<C>: Serialize + crate::__private::StructuralDataSealed<C>
+where
+    C: ProgramCollect<Enum = C>,
+{
+}