Add assertion that second argument of cast_func is of type pymbolics.data_type.Type

pystencils/data_types.py

@@ -54,6 +54,7 @@ class cast_func(sp.Function):
         # rhs = cast_func(0, 'int')
         # print( sp.Ne(lhs, rhs) ) # would give true if all cast_funcs are booleans
         # -> thus a separate class boolean_cast_func is introduced
+        assert isinstance(args[1], Type), "Second argument of cast_func must be of type pymbolics.data_type.Type"
         if isinstance(args[0], Boolean):
             cls = boolean_cast_func
         return sp.Function.__new__(cls, *args, **kwargs)