diff --git a/meshmode/discretization/connection/__init__.py b/meshmode/discretization/connection/__init__.py
index 7d17be88ed122ccf5b9ee1d1098fe9da79899bb4..0143a9499f3ca5dafae4454d3d628a997e7a6f29 100644
--- a/meshmode/discretization/connection/__init__.py
+++ b/meshmode/discretization/connection/__init__.py
@@ -451,7 +451,7 @@ class DirectDiscretizationConnection(DiscretizationConnection):
             return lp.tag_inames(knl, dict(k="g.0"))
 
         if not isinstance(vec, cl.array.Array):
-            return vec
+            raise TypeError("non-array passed to discretization connection")
 
         if self.is_surjective:
             result = self.to_discr.empty(dtype=vec.dtype)