Syntax error for two-level list comprehension with condition

[pmbethe09]

genrule(
name = "test",
outs = [
"%s/%s.txt" % (dictionary["folder_name"], file_name)
for dictionary in DICTIONARIES if dictionary["enabled"]
for file_name in dictionary["file_names"]
],
cmd = "touch $(OUTS)",
)

Is valid in bazel, but not buildifier's grammar.