Check type before sending #value message to predicate

The previous implementation was giving for granted that every predicate
respond  to `#value`, but that doesn't seem to be the case at least when
having a `Arel::SelectManager`.

by simply inverting the terms of the existing AND check we can fix the issue
without introducing unknown side effects.

In order to test the change, a new ransacker has been added to the Person model.

lib/ransack/nodes/condition.rb

@@ -339,7 +339,7 @@ def in_predicate?(predicate)
       end
 
       def casted_array?(predicate)
-        predicate.value.is_a?(Array) && predicate.is_a?(Arel::Nodes::Casted)
+        predicate.is_a?(Arel::Nodes::Casted) && predicate.value.is_a?(Array)
       end
 
       def format_values_for(predicate)

spec/ransack/adapters/active_record/base_spec.rb

@@ -408,6 +408,15 @@ def self.simple_escaping?
               expect(s.result.map(&:id)).to eq [3, 2, 1]
             end
 
+            it 'should function correctly with HABTM associations' do
+              article = Article.first
+              tag = article.tags.first
+              s = Person.ransack(article_tags_in: [tag.id])
+
+              expect(s.result.count).to be 1
+              expect(s.result.map(&:id)).to eq [article.person.id]
+            end
+
             it 'should function correctly when passing an array of strings' do
               a, b = Person.select(:id).order(:id).limit(2).map { |a| a.id.to_s }
 

spec/support/schema.rb

@@ -126,6 +126,17 @@ class Person < ApplicationRecord
     Arel.sql(query)
   end
 
+  ransacker :article_tags, formatter: proc { |id|
+    if Tag.exists?(id)
+      joins(articles: :tags)
+        .where(tags: { id: id })
+        .distinct
+        .select(:id).arel
+    end
+  } do |parent|
+    parent.table[:id]
+  end
+
   def self.ransackable_attributes(auth_object = nil)
     if auth_object == :admin
       authorizable_ransackable_attributes - ['only_sort']