--- a/crates/jrsonnet-evaluator/src/builtin/manifest.rs
+++ b/crates/jrsonnet-evaluator/src/builtin/manifest.rs
@@ -80,6 +80,7 @@
 			buf.push(']');
 		}
 		Val::Obj(obj) => {
+			obj.run_assertions()?;
 			buf.push('{');
 			let fields = obj.fields();
 			if !fields.is_empty() {