Merge branch 'custom-fields-different-size-in-transformations' into 'master'

Allow `CUSTOM_FIELD`s to have a different size in transformations.py

See merge request pycodegen/pystencils!107

pystencils/transformations.py

@@ -168,7 +168,7 @@ def make_loop_over_domain(body, iteration_slice=None, ghost_layers=None, loop_or
     field_accesses = {e for e in field_accesses if not e.is_absolute_access}
 
     # exclude accesses to buffers from field_list, because buffers are treated separately
-    field_list = [e.field for e in field_accesses if not FieldType.is_buffer(e.field)]
+    field_list = [e.field for e in field_accesses if not (FieldType.is_buffer(e.field) or FieldType.is_custom(e.field))]
     fields = set(field_list)
 
     if loop_order is None: