$ egrep -rl ', r.Err = c\.[A-Z][a-z]+\('
openstack/networking/v2/extensions/fwaas_v2/groups/requests.go
openstack/networking/v2/extensions/fwaas_v2/policies/requests.go
The code was added in #2050 after the #1942 was merged.
Maybe we can implement a linter to avoid such cases?