feat(core): add generic parameter `C` to `StructuralData` trait

Make `StructuralData` and `StructuralDataSealed` generic over a program
collector type to bypass the orphan rule for `group_structural!`. This
enables external types to implement `StructuralData<crate::ThisProgram>`
without violating coherence.

1 files changed, 7 insertions, 1 deletions

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>,
+{
+}