Expose native implementation identity for verified host fast paths

crates/objects/src/native.rs

@@ -222,7 +222,7 @@ impl CallSignature {
     }
 }
 
-pub trait NativeCallable: fmt::Debug + Send + Sync + 'static {
+pub trait NativeCallable: fmt::Debug + Send + Sync + std::any::Any {
     /// Immutable resolved types; referenced definitions must be traced by the
     /// payload. ContextNativeFunction snapshots and traces them automatically.
     fn signature(&self) -> Option<CallSignature> {
@@ -453,6 +453,14 @@ pub struct ContextNativeFunction {
 }
 
 impl ContextNativeFunction {
+    /// Borrow the concrete host implementation for intrinsic dispatch checks.
+    /// Function identity or a mutable class-table slot alone is not proof that
+    /// its current payload still implements a host intrinsic.
+    pub fn implementation<T: NativeCallable>(&self) -> Option<&T> {
+        let implementation: &dyn std::any::Any = self.callable.as_ref();
+        implementation.downcast_ref()
+    }
+
     pub fn new(
         name: &'static str,
         callable: impl NativeCallable,