Highlight broken code path

python/dune/perftool/sumfact/quadrature.py

@@ -236,5 +236,8 @@ def pymbolic_indexed_quadrature_position(index, visitor):
 
 @backend(interface="qp_in_cell", name="sumfact")
 def pymbolic_quadrature_position_in_cell(restriction):
+    # TODO: This code path is broken at the moment.
+    assert False
+
     from dune.perftool.pdelab.geometry import to_cell_coordinates
     return to_cell_coordinates(pymbolic_quadrature_position(), restriction)