rails/rails — pull request #16503 by bogdan (2014-08-14 15:42:31+00:00)
Title: Fixed AR::Relation#where edge case with Hash and other Relation

Example:

Author.where(posts: { author_id: Author.where(country_id: 1) }).joins(:posts)

Conflicts:
activerecord/lib/active_record/relation/query_methods.rb