1 files changed, 5 insertions, 0 deletions
diff --git a/tvix/eval/src/errors.rs b/tvix/eval/src/errors.rs
index ad4acd479e05..b87555d06d52 100644
--- a/tvix/eval/src/errors.rs
+++ b/tvix/eval/src/errors.rs
@@ -58,6 +58,11 @@ pub enum ErrorKind {
     /// An error occured while forcing a thunk, and needs to be
     /// chained up.
     ThunkForce(Box<Error>),
+
+    /// Tvix internal warning for features triggered by users that are
+    /// not actually implemented yet, and without which eval can not
+    /// proceed.
+    NotImplemented(&'static str),
 }
 
 #[derive(Clone, Debug)]