diff --git a/pystencils/astnodes.py b/pystencils/astnodes.py
index b24138286c024d0e7b546488289e552620a6d125..a0ca26fdd9efb9be827ef5ffbf2deed9d5a79a1f 100644
--- a/pystencils/astnodes.py
+++ b/pystencils/astnodes.py
@@ -569,7 +569,9 @@ class SympyAssignment(Node):
 class ResolvedFieldAccess(sp.Indexed):
     def __new__(cls, base, linearized_index, field, offsets, idx_coordinate_values):
         if not isinstance(base, sp.IndexedBase):
+            assert isinstance(base, TypedSymbol)
             base = sp.IndexedBase(base, shape=(1,))
+            assert isinstance(base.label, TypedSymbol)
         obj = super(ResolvedFieldAccess, cls).__new__(cls, base, linearized_index)
         obj.field = field
         obj.offsets = offsets