rails/rails — pull request #12401 by airlok (2013-10-07 17:06:06+00:00)
Title: Inconsistent Association#include?

**What happens:** Calling `include?` on Association objects sometimes returns an integer, sometimes a boolean.
**Expected:** `include?` should always return true or false.
**Occurs using:** Ruby 2.0.0p247, Rails 4.0.0

### To reproduce
1. Create association: **user has_many locations**
2. Run this:

```ruby
user.locations.include?(location)
=> 1

puts user.locations
=> #
user.locations.include?(location)
=> true
```

`puts` is required to get the expected output with Association#include?