Test nested fields with AssociationProxy mockup & fix AssociationProxy support in form helper
clearer conditional in constraint match check
Covering untested methods for ActiveModel::Errors
Merge pull request #8623 from virusman/form_helpers_collectionproxy_fix

Fixed nested fields bug when called with AssociationProxy
Merge pull request #8866 from adomokos/adding_more_tests_to_errors_test

Adding tests to cover untested methods in errors_tests.rb
Merge pull request #8882 from goshakkk/clearer-conditional

Clearer conditional in constraint match check